WorldWideScience

Sample records for higher detection frequencies

  1. [Detection of a higher incidence of pathologic somatic findings in globus sensation by use of high frequency cinematography].

    Science.gov (United States)

    Hannig, C; Wuttge-Hannig, A; Bockmeyer, M

    1987-07-01

    Since December 1984 303 patients have undergone examination in our Multidisciplinary Consultation Service for Swallowing Disorders; 117 of them were suffering from typical globus symptoms. We were able to increase the yield of detection of organic lesions by use of the technique of 35 mm film cineradiography with a rate of 50 frames/s. Frame-by-frame analysis and computer-assisted evaluation showed that 80% of the patients with globus symptoms suffered from one or more underlying organic diseases, which could often be treated later with success. We found an increased incidence of early hypopharyngeal diverticula, webs, and motility disorders of the upper esophageal sphincter often associated with gastro-esophageal reflux or weakness of the pharyngeal wall. Cineradiography proved to be a very important tool in the analysis of the pharyngeal swallow in globus pharyngis.

  2. Piping system damping data at higher frequencies

    International Nuclear Information System (INIS)

    Ware, A.G.

    1987-01-01

    Research has been performed at the Idaho National Engineering Laboratory (INEL) for the United States Nuclear Regulatory Commission (USNRC) to determine best-estimate damping values for dynamic analyses of nuclear piping systems excited in the 20 to 100 Hz frequency range. Vibrations in this frequency range are typical of fluid-induced transients, for which no formal pipe damping guidelines exist. The available data found in the open literature and the USNRC/INEL nuclear piping damping data bank were reviewed, and a series of tests on a straight 3-in. (76-mm) piping system and a 5-in. (127-mm) system with several bends and elbows were conducted as part of this research program. These two systems were supported with typical nuclear piping supports that could be changed from test to test during the series. The resulting damping values were ≥ those of the Pressure Vessel Research Committee (PVRC) proposal for unisulated piping. Extending the PVRC damping curve from 20 to 100 Hz at 3% of critical damping would give a satisfactory representation of the test data. This position has been endorsed by the PVRC Technical Committee on Piping Systems. 14 refs

  3. Amplitude modulation detection with concurrent frequency modulation.

    Science.gov (United States)

    Nagaraj, Naveen K

    2016-09-01

    Human speech consists of concomitant temporal modulations in amplitude and frequency that are crucial for speech perception. In this study, amplitude modulation (AM) detection thresholds were measured for 550 and 5000 Hz carriers with and without concurrent frequency modulation (FM), at AM rates crucial for speech perception. Results indicate that adding 40 Hz FM interferes with AM detection, more so for 5000 Hz carrier and for frequency deviations exceeding the critical bandwidth of the carrier frequency. These findings suggest that future cochlear implant processors, encoding speech fine-structures may consider limiting the FM to narrow bandwidth and to low frequencies.

  4. Frequency Based Fault Detection in Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2014-01-01

    In order to obtain lower cost of energy for wind turbines fault detection and accommodation is important. Expensive condition monitoring systems are often used to monitor the condition of rotating and vibrating system parts. One example is the gearbox in a wind turbine. This system is operated...... in parallel to the control system, using different computers and additional often expensive sensors. In this paper a simple filter based algorithm is proposed to detect changes in a resonance frequency in a system, exemplified with faults resulting in changes in the resonance frequency in the wind turbine...... gearbox. Only the generator speed measurement which is available in even simple wind turbine control systems is used as input. Consequently this proposed scheme does not need additional sensors and computers for monitoring the condition of the wind gearbox. The scheme is evaluated on a wide-spread wind...

  5. The potential for very high-frequency gravitational wave detection

    International Nuclear Information System (INIS)

    Cruise, A M

    2012-01-01

    The science case for observing gravitational waves at frequencies in the millihertz-kilohertz range using LIGO, VIRGO, GEO600 or LISA is very strong and the first results are expected at these frequencies. However, as gravitational wave astronomy progresses beyond the first detections, other frequency bands may be worth exploring. Early predictions of gravitational wave emission from discrete sources at very much higher frequencies (megahertz and above) have been published and more recent studies of cosmological signals from inflation, Kaluza-Klein modes from gravitational interactions in brane worlds and plasma instabilities surrounding violent astrophysical events, are all possible sources. This communication examines current observational possibilities and the detector technology required to make meaningful observations at these frequencies. (paper)

  6. Radio frequency plasma nitriding of aluminium at higher power levels

    International Nuclear Information System (INIS)

    Gredelj, Sabina; Kumar, Sunil; Gerson, Andrea R.; Cavallaro, Giuseppe P.

    2006-01-01

    Nitriding of aluminium 2011 using a radio frequency plasma at higher power levels (500 and 700 W) and lower substrate temperature (500 deg. C) resulted in higher AlN/Al 2 O 3 ratios than obtained at 100 W and 575 deg. C. AlN/Al 2 O 3 ratios derived from X-ray photoelectron spectroscopic analysis (and corroborated by heavy ion elastic recoil time of flight spectrometry) for treatments preformed at 100 (575 deg. C), 500 (500 deg. C) and 700 W (500 deg. C) were 1.0, 1.5 and 3.3, respectively. Scanning electron microscopy revealed that plasma nitrided surfaces obtained at higher power levels exhibited much finer nodular morphology than obtained at 100 W

  7. Extended Opacity Tables with Higher Temperature-Density-Frequency Resolution

    Science.gov (United States)

    Schillaci, Mark; Orban, Chris; Delahaye, Franck; Pinsonneault, Marc; Nahar, Sultana; Pradhan, Anil

    2015-05-01

    Theoretical models for plasma opacities underpin our understanding of radiation transport in many different astrophysical objects. These opacity models are also relevant to HEDP experiments such as ignition scale experiments on NIF. We present a significantly expanded set of opacity data from the widely utilized Opacity Project, and make these higher resolution data publicly available through OSU's portal with dropbox.com. This expanded data set is used to assess how accurate the interpolation of opacity data in temperature-density-frequency dimensions must be in order to adequately model the properties of most stellar types. These efforts are the beginning of a larger project to improve the theoretical opacity models in light of experimental results at the Sandia Z-pinch showing that the measured opacity of Iron disagrees strongly with all current models.

  8. Higher Eating Frequency Does Not Decrease Appetite in Healthy Adults.

    Science.gov (United States)

    Perrigue, Martine M; Drewnowski, Adam; Wang, Ching-Yun; Neuhouser, Marian L

    2016-01-01

    Consumption of small, frequent meals is suggested as an effective approach to control appetite and food intake and might be a strategy for weight loss or healthy weight maintenance. Despite much speculation on the topic, scientific evidence is limited to support such a relation in the absence of changes to diet composition. We examined the effects of high compared with low eating frequency (EF) on self-reported appetite as a secondary outcome in a controlled trial. We conducted a randomized, crossover intervention trial in 12 participants (4 men, 8 women) who completed 2 isocaloric 3-wk intervention phases of low EF (3 eating occasions/d) compared with high EF (8 eating occasions/d). On the last morning of each study phase, participants completed a 4-h appetite testing session. During the appetite testing session, participants completing the low EF phase consumed a meal at 0800. Participants completing the high EF intervention consumed the same meal spread evenly over 2 eating occasions at 0800 and 1030. Standardized ratings of hunger, desire to eat, fullness, thirst, and nausea were completed every 30 min with the use of paper-and-pencil semianchored 100-mm visual analog scales. A composite appetite score was calculated as the mean of hunger, desire to eat, and the inverse of fullness (calculated as 100-fullness rating). Linear regression analysis compared ratings between low EF and high EF conditions. The mean composite appetite score was higher in the high EF condition for the total testing period (baseline through 1200) (P appetite. This trial was registered at clinicaltrials.gov as NCT02548026. © 2016 American Society for Nutrition.

  9. Coral larvae settle at a higher frequency on red surfaces

    Science.gov (United States)

    Mason, B.; Beard, M.; Miller, M. W.

    2011-09-01

    Although chemical cues serve as the primary determinants of larval settlement and metamorphosis, light is also known to influence the behavior and the settlement of coral planulae. For example, Porites astreoides planulae settle preferentially on unconditioned red substrata. In order to test whether this behavior was a response to color and whether other species also demonstrate color preference, settlement choice experiments were conducted with P. astreoides and Acropora palmata. In these experiments, larvae were offered various types of plastic substrata representing three to seven different color choices. Both species consistently settled on red (or red and orange) substrata at a higher frequency than other colors. In one experiment, P. astreoides settled on 100% of red, plastic cable ties but failed to settle on green or white substrata. In a second experiment, 24% of larvae settled on red buttons, more than settled on six other colors combined. A. palmata settled on 80% of red and of orange cables ties but failed to settle on blue in one experiment and settled on a greater proportion of red acrylic squares than on four other colors or limestone controls in a second experiment. The consistency of the response across a variety of plastic materials suggests the response is related to long-wavelength photosensitivity. Fluorescence and reflectance spectra of experimental substrata demonstrated that the preferred substrata had spectra dominated by wavelengths greater than 550 nm with little or no reflection or emission of shorter wavelengths. These results suggest that some species of coral larvae may use spectral cues for fine-scale habitat selection during settlement. This behavior may be an adaptation to promote settlement in crustose coralline algae (CCA)-dominated habitats facilitating juvenile survival.

  10. Beat frequency ultrasonic microsphere contrast agent detection system

    Science.gov (United States)

    Pretlow, III, Robert A. (Inventor); Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

    1997-01-01

    A system for and method of detecting and measuring concentrations of an ultrasonically-reflective microsphere contrast agent involving detecting non-linear sum and difference beat frequencies produced by the microspheres when two impinging signals with non-identical frequencies are combined by mixing. These beat frequencies can be used for a variety of applications such as detecting the presence of and measuring the flow rates of biological fluids and industrial liquids, including determining the concentration level of microspheres in the myocardium.

  11. Higher frequency network activity flow predicts lower frequency node activity in intrinsic low-frequency BOLD fluctuations.

    Science.gov (United States)

    Bajaj, Sahil; Adhikari, Bhim Mani; Dhamala, Mukesh

    2013-01-01

    The brain remains electrically and metabolically active during resting conditions. The low-frequency oscillations (LFO) of the blood oxygen level-dependent (BOLD) signal of functional magnetic resonance imaging (fMRI) coherent across distributed brain regions are known to exhibit features of this activity. However, these intrinsic oscillations may undergo dynamic changes in time scales of seconds to minutes during resting conditions. Here, using wavelet-transform based time-frequency analysis techniques, we investigated the dynamic nature of default-mode networks from intrinsic BOLD signals recorded from participants maintaining visual fixation during resting conditions. We focused on the default-mode network consisting of the posterior cingulate cortex (PCC), the medial prefrontal cortex (mPFC), left middle temporal cortex (LMTC) and left angular gyrus (LAG). The analysis of the spectral power and causal flow patterns revealed that the intrinsic LFO undergo significant dynamic changes over time. Dividing the frequency interval 0 to 0.25 Hz of LFO into four intervals slow-5 (0.01-0.027 Hz), slow-4 (0.027-0.073 Hz), slow-3 (0.073-0.198 Hz) and slow-2 (0.198-0.25 Hz), we further observed significant positive linear relationships of slow-4 in-out flow of network activity with slow-5 node activity, and slow-3 in-out flow of network activity with slow-4 node activity. The network activity associated with respiratory related frequency (slow-2) was found to have no relationship with the node activity in any of the frequency intervals. We found that the net causal flow towards a node in slow-3 band was correlated with the number of fibers, obtained from diffusion tensor imaging (DTI) data, from the other nodes connecting to that node. These findings imply that so-called resting state is not 'entirely' at rest, the higher frequency network activity flow can predict the lower frequency node activity, and the network activity flow can reflect underlying structural

  12. Helper T lymphocyte precursor frequency analysis in alloreactivity detection

    International Nuclear Information System (INIS)

    Cukrova, V.; Dolezalova, L.; Loudova, M.; Vitek, A.

    1998-01-01

    The utility of IL-2 secreting helper T lymphocyte precursors (HTLp) frequency testing has been evaluated for detecting alloreactivity. The frequency of HTLp was approached by limiting dilution assay. High HTLp frequency was detected in 20 out of 30 HLA matched unrelated pairs (67%). The comparison of HTLp and CTLp (cytotoxic T lymphocyte precursors) frequencies in HLA matched unrelated pairs showed that the two examinations are not fully alternative in detecting alloreactivity. This could suggest the utility of combined testing of both HTLp and CTLp frequencies for alloreactivity assessment. In contrast, five positive HTLp values were only found among 28 HLA genotypic identical siblings (18%). Previous CTLp limiting dilution studies showed very low or undetectable CTLp frequency results in that group. For that, HTLp assay remains to be the only cellular in vitro technique detecting alloreactivity in these combinations. (authors)

  13. Low velocity target detection based on time-frequency image for high frequency ground wave radar

    Institute of Scientific and Technical Information of China (English)

    YAN Songhua; WU Shicai; WEN Biyang

    2007-01-01

    The Doppler spectral broadening resulted from non-stationary movement of target and radio-frequency interference will decrease the veracity of target detection by high frequency ground wave(HEGW)radar.By displaying the change of signal energy on two dimensional time-frequency images based on time-frequency analysis,a new mathematical morphology method to distinguish target from nonlinear time-frequency curves is presented.The analyzed results from the measured data verify that with this new method the target can be detected correctly from wide Doppler spectrum.

  14. Frequency of urogenital mycoplasma detection in women of Dnipropetrovsk

    Directory of Open Access Journals (Sweden)

    K. V. Bubalo

    2014-04-01

    Full Text Available The frequency of urogenital mycoplasmas detection in women of different ages was studied in culture with the help of DUO test-system in order to determine their etiological significance in the development of inflammatory processes of women urogenital tract. We identified the researched cultures Mycoplasma hominis, Ureaplasma urealyticum in the diagnostic titer >104 TEM/ml indicating severe contamination by microorganisms, and in the titer 104 TEM/ml, 104 TEM/ml was observed in 55 women (46% and 20 women (17%, respectively, and the titer of <103 CFU/ml U. urealyticum was observed in 20 women (17%, and M. hominis in 18 women (15%. Analysis of genital mycoplasmas distribution among women of different ages has shown that there was the certain correlation between the patient age and frequency of genital mycoplasmas detection: the highest detection rate was observed in women age of 24–29. The dominant pathogen of urogenital tract inflammatory processes in women in 24–29 age group is U. urealyticum. The comparison of DUO test-system and PCR data has shown that DUO test-system in culture allowed more sensitive quantitave characterization of mycoplasmas, however, for the more effective laboratory diagnostics it was necessary to use complex methods to increase the probability of pathogen detection. Incidence of mycoplasmas in women with the presence of inflammation was higher than in women having the inflammation in the genital tract. In this case, potential symptom-free carriers exist for the development of inflammation of urogenital tract of women. Scientists have proved that mycoplasma could cause vulvovaginitis, urethritis, paraurethritis, bartholinitis, adnexitis, salpingitis, endometritis, and ovaritis.

  15. Higher frequency of cholelithiasis in eosinophilic cholecystitis, an unusual finding

    International Nuclear Information System (INIS)

    Sarfraz, T.; Tariq, H.; Bashir, S.

    2015-01-01

    To determine the frequency of cholelithiasis in eosinophilic cholecystitis in our population. Study Design: Prospective descriptive study. Place and Duration of Study: Histopathology department, Combined Military Hospital (CMH), Peshawar (Pakistan) from Dec 2011 to Nov 2014. Material and Methods: Eighteen hundred (1800) cholecystectomy specimens were included in the study. The specimens which were properly fixed in 10% formalin were included in the specimen, while poorly fixed and autolysed specimens were excluded. The specimens were examined grossly, measured and block selection was done. The slides made were examined under light microscope by one histopathologist and findings were analyzed. Results: Out of 1800 cholecystectomy specimens, 25 cases (1.38%) were diagnosed as eosinophilic cholecystitis. Out of these 25 cases, 20 (80%) were females having an age range of 30-50 years, while 5 (20%) were males with an age range of 35-55 years. Out of these 25 cases of eosinophilic cholecystitis, 22 (88%) were having cholelithiasis, while 3 (12%) were acalculous eosiniophilic cholecystitis. Conclusion: Eosinophilic cholecystitis in our population is mostly calculous which is very significant finding contrary to data given in western literature, where most of eosinophilic cholecystitis is aclculous. This needs further evaluation to determine any genetic, geographic, environmental, dietary, microbiological or any other factor responsible in etiopathogenesis of calculous eosinophilic cholecystitis in our population, which could be helpful in prevention and management of this disease. (author)

  16. Investigating Strength and Frequency Effects in Recognition Memory Using Type-2 Signal Detection Theory

    Science.gov (United States)

    Higham, Philip A.; Perfect, Timothy J.; Bruno, Davide

    2009-01-01

    Criterion- versus distribution-shift accounts of frequency and strength effects in recognition memory were investigated with Type-2 signal detection receiver operating characteristic (ROC) analysis, which provides a measure of metacognitive monitoring. Experiment 1 demonstrated a frequency-based mirror effect, with a higher hit rate and lower…

  17. Measurement of optical-beat frequency in a photoconductive terahertz-wave generator using microwave higher harmonics.

    Science.gov (United States)

    Murasawa, Kengo; Sato, Koki; Hidaka, Takehiko

    2011-05-01

    A new method for measuring optical-beat frequencies in the terahertz (THz) region using microwave higher harmonics is presented. A microwave signal was applied to the antenna gap of a photoconductive (PC) device emitting a continuous electromagnetic wave at about 1 THz by the photomixing technique. The microwave higher harmonics with THz frequencies are generated in the PC device owing to the nonlinearity of the biased photoconductance, which is briefly described in this article. Thirteen nearly periodic peaks in the photocurrent were observed when the microwave was swept from 16 to 20 GHz at a power of -48 dBm. The nearly periodic peaks are generated by the homodyne detection of the optical beat with the microwave higher harmonics when the frequency of the harmonics coincides with the optical-beat frequency. Each peak frequency and its peak width were determined by fitting a Gaussian function, and the order of microwave harmonics was determined using a coarse (i.e., lower resolution) measurement of the optical-beat frequency. By applying the Kalman algorithm to the peak frequencies of the higher harmonics and their standard deviations, the optical-beat frequency near 1 THz was estimated to be 1029.81 GHz with the standard deviation of 0.82 GHz. The proposed method is applicable to a conventional THz-wave generator with a photomixer.

  18. Dispersive detection of radio-frequency-dressed states

    Science.gov (United States)

    Jammi, Sindhu; Pyragius, Tadas; Bason, Mark G.; Florez, Hans Marin; Fernholz, Thomas

    2018-04-01

    We introduce a method to dispersively detect alkali-metal atoms in radio-frequency-dressed states. In particular, we use dressed detection to measure populations and population differences of atoms prepared in their clock states. Linear birefringence of the atomic medium enables atom number detection via polarization homodyning, a form of common path interferometry. In order to achieve low technical noise levels, we perform optical sideband detection after adiabatic transformation of bare states into dressed states. The balanced homodyne signal then oscillates independently of field fluctuations at twice the dressing frequency, thus allowing for robust, phase-locked detection that circumvents low-frequency noise. Using probe pulses of two optical frequencies, we can detect both clock states simultaneously and obtain population difference as well as the total atom number. The scheme also allows for difference measurements by direct subtraction of the homodyne signals at the balanced detector, which should technically enable quantum noise limited measurements with prospects for the preparation of spin squeezed states. The method extends to other Zeeman sublevels and can be employed in a range of atomic clock schemes, atom interferometers, and other experiments using dressed atoms.

  19. Detecting high-frequency gravitational waves with optically levitated sensors.

    Science.gov (United States)

    Arvanitaki, Asimina; Geraci, Andrew A

    2013-02-15

    We propose a tunable resonant sensor to detect gravitational waves in the frequency range of 50-300 kHz using optically trapped and cooled dielectric microspheres or microdisks. The technique we describe can exceed the sensitivity of laser-based gravitational wave observatories in this frequency range, using an instrument of only a few percent of their size. Such a device extends the search volume for gravitational wave sources above 100 kHz by 1 to 3 orders of magnitude, and could detect monochromatic gravitational radiation from the annihilation of QCD axions in the cloud they form around stellar mass black holes within our galaxy due to the superradiance effect.

  20. Correcting length-frequency distributions for imperfect detection

    Science.gov (United States)

    Breton, André R.; Hawkins, John A.; Winkelman, Dana L.

    2013-01-01

    Sampling gear selects for specific sizes of fish, which may bias length-frequency distributions that are commonly used to assess population size structure, recruitment patterns, growth, and survival. To properly correct for sampling biases caused by gear and other sources, length-frequency distributions need to be corrected for imperfect detection. We describe a method for adjusting length-frequency distributions when capture and recapture probabilities are a function of fish length, temporal variation, and capture history. The method is applied to a study involving the removal of Smallmouth Bass Micropterus dolomieu by boat electrofishing from a 38.6-km reach on the Yampa River, Colorado. Smallmouth Bass longer than 100 mm were marked and released alive from 2005 to 2010 on one or more electrofishing passes and removed on all other passes from the population. Using the Huggins mark–recapture model, we detected a significant effect of fish total length, previous capture history (behavior), year, pass, year×behavior, and year×pass on capture and recapture probabilities. We demonstrate how to partition the Huggins estimate of abundance into length frequencies to correct for these effects. Uncorrected length frequencies of fish removed from Little Yampa Canyon were negatively biased in every year by as much as 88% relative to mark–recapture estimates for the smallest length-class in our analysis (100–110 mm). Bias declined but remained high even for adult length-classes (≥200 mm). The pattern of bias across length-classes was variable across years. The percentage of unadjusted counts that were below the lower 95% confidence interval from our adjusted length-frequency estimates were 95, 89, 84, 78, 81, and 92% from 2005 to 2010, respectively. Length-frequency distributions are widely used in fisheries science and management. Our simple method for correcting length-frequency estimates for imperfect detection could be widely applied when mark–recapture data

  1. Effect of higher frequency on the classification of steady-state visual evoked potentials

    Science.gov (United States)

    Won, Dong-Ok; Hwang, Han-Jeong; Dähne, Sven; Müller, Klaus-Robert; Lee, Seong-Whan

    2016-02-01

    Objective. Most existing brain-computer interface (BCI) designs based on steady-state visual evoked potentials (SSVEPs) primarily use low frequency visual stimuli (e.g., visual fatigue and no stimulus-related seizures. The fundamental objective of this study was to investigate the effect of stimulation frequency and duty-cycle on the usability of an SSVEP-based BCI system. Approach. We developed an SSVEP-based BCI speller using multiple LEDs flickering with low frequencies (6-14.9 Hz) with a duty-cycle of 50%, or higher frequencies (26-34.7 Hz) with duty-cycles of 50%, 60%, and 70%. The four different experimental conditions were tested with 26 subjects in order to investigate the impact of stimulation frequency and duty-cycle on performance and visual fatigue, and evaluated with a questionnaire survey. Resting state alpha powers were utilized to interpret our results from the neurophysiological point of view. Main results. The stimulation method employing higher frequencies not only showed less visual fatigue, but it also showed higher and more stable classification performance compared to that employing relatively lower frequencies. Different duty-cycles in the higher frequency stimulation conditions did not significantly affect visual fatigue, but a duty-cycle of 50% was a better choice with respect to performance. The performance of the higher frequency stimulation method was also less susceptible to resting state alpha powers, while that of the lower frequency stimulation method was negatively correlated with alpha powers. Significance. These results suggest that the use of higher frequency visual stimuli is more beneficial for performance improvement and stability as time passes when developing practical SSVEP-based BCI applications.

  2. Ultrasensitive detection of atmospheric trace gases using frequency modulation spectroscopy

    Science.gov (United States)

    Cooper, David E.

    1986-01-01

    Frequency modulation (FM) spectroscopy is a new technique that promises to significantly extend the state-of-the-art in point detection of atmospheric trace gases. FM spectroscopy is essentially a balanced bridge optical heterodyne approach in which a small optical absorption or dispersion from an atomic or molecular species of interest generates an easily detected radio frequency (RF) signal. This signal can be monitored using standard RF signal processing techniques and is, in principle, limited only by the shot noise generated in the photodetector by the laser source employed. The use of very high modulation frequencies which exceed the spectral width of the probed absorption line distinguishes this technique from the well-known derivative spectroscopy which makes use of low (kHz) modulation frequencies. FM spectroscopy was recently extended to the 10 micron infrared (IR) spectral region where numerous polyatomic molecules exhibit characteristic vibrational-rotational bands. In conjunction with tunable semiconductor diode lasers, the quantum-noise-limited sensitivity of the technique should allow for the detection of absorptions as small as .00000001 in the IR spectral region. This sensitivity would allow for the detection of H2O2 at concentrations as low as 1 pptv with an integration time of 10 seconds.

  3. Fault detection of gearbox using time-frequency method

    Science.gov (United States)

    Widodo, A.; Satrijo, Dj.; Prahasto, T.; Haryanto, I.

    2017-04-01

    This research deals with fault detection and diagnosis of gearbox by using vibration signature. In this work, fault detection and diagnosis are approached by employing time-frequency method, and then the results are compared with cepstrum analysis. Experimental work has been conducted for data acquisition of vibration signal thru self-designed gearbox test rig. This test-rig is able to demonstrate normal and faulty gearbox i.e., wears and tooth breakage. Three accelerometers were used for vibration signal acquisition from gearbox, and optical tachometer was used for shaft rotation speed measurement. The results show that frequency domain analysis using fast-fourier transform was less sensitive to wears and tooth breakage condition. However, the method of short-time fourier transform was able to monitor the faults in gearbox. Wavelet Transform (WT) method also showed good performance in gearbox fault detection using vibration signal after employing time synchronous averaging (TSA).

  4. Higher-Order Cyclostationarity Detection for Spectrum Sensing

    Directory of Open Access Journals (Sweden)

    Julien Renard

    2010-01-01

    Full Text Available Recent years have shown a growing interest in the concept of Cognitive Radios (CRs, able to access portions of the electromagnetic spectrum in an opportunistic operating way. Such systems require efficient detectors able to work in low Signal-to-Noise Ratio (SNR environments, with little or no information about the signals they are trying to detect. Energy detectors are widely used to perform such blind detection tasks, but quickly reach the so-called SNR wall below which detection becomes impossible Tandra (2005. Cyclostationarity detectors are an interesting alternative to energy detectors, as they exploit hidden periodicities present in man-made signals, but absent in noise. Such detectors use quadratic transformations of the signals to extract the hidden sine-waves. While most of the literature focuses on the second-order transformations of the signals, we investigate the potential of higher-order transformations of the signals. Using the theory of Higher-Order Cyclostationarity (HOCS, we derive a fourth-order detector that performs similarly to the second-order ones to detect linearly modulated signals, at SNR around 0 dB, which may be used if the signals of interest do not exhibit second-order cyclostationarity. More generally this paper reviews the relevant aspects of the cyclostationary and HOCS theory, and shows their potential for spectrum sensing.

  5. A Frequency-Based Approach to Intrusion Detection

    Directory of Open Access Journals (Sweden)

    Mian Zhou

    2004-06-01

    Full Text Available Research on network security and intrusion detection strategies presents many challenging issues to both theoreticians and practitioners. Hackers apply an array of intrusion and exploit techniques to cause disruption of normal system operations, but on the defense, firewalls and intrusion detection systems (IDS are typically only effective in defending known intrusion types using their signatures, and are far less than mature when faced with novel attacks. In this paper, we adapt the frequency analysis techniques such as the Discrete Fourier Transform (DFT used in signal processing to the design of intrusion detection algorithms. We demonstrate the effectiveness of the frequency-based detection strategy by running synthetic network intrusion data in simulated networks using the OPNET software. The simulation results indicate that the proposed intrusion detection strategy is effective in detecting anomalous traffic data that exhibit patterns over time, which include several types of DOS and probe attacks. The significance of this new strategy is that it does not depend on the prior knowledge of attack signatures, thus it has the potential to be a useful supplement to existing signature-based IDS and firewalls.

  6. A current drive by using the fast wave in frequency range higher than two timeslower hybrid resonance frequency on tokamaks

    Directory of Open Access Journals (Sweden)

    Kim Sun Ho

    2017-01-01

    Full Text Available An efficient current drive scheme in central or off-axis region is required for the steady state operation of tokamak fusion reactors. The current drive by using the fast wave in frequency range higher than two times lower hybrid resonance (w>2wlh could be such a scheme in high density, high temperature reactor-grade tokamak plasmas. First, it has relatively higher parallel electric field to the magnetic field favorable to the current generation, compared to fast waves in other frequency range. Second, it can deeply penetrate into high density plasmas compared to the slow wave in the same frequency range. Third, parasitic coupling to the slow wave can contribute also to the current drive avoiding parametric instability, thermal mode conversion and ion heating occured in the frequency range w<2wlh. In this study, the propagation boundary, accessibility, and the energy flow of the fast wave are given via cold dispersion relation and group velocity. The power absorption and current drive efficiency are discussed qualitatively through the hot dispersion relation and the polarization. Finally, those characteristics are confirmed with ray tracing code GENRAY for the KSTAR plasmas.

  7. CSI Frequency Domain Fingerprint-Based Passive Indoor Human Detection

    Directory of Open Access Journals (Sweden)

    Chong Han

    2018-04-01

    Full Text Available Passive indoor personnel detection technology is now a hot topic. Existing methods have been greatly influenced by environmental changes, and there are problems with the accuracy and robustness of detection. Passive personnel detection based on Wi-Fi not only solves the above problems, but also has the advantages of being low cost and easy to implement, and can be better applied to elderly care and safety monitoring. In this paper, we propose a passive indoor personnel detection method based on Wi-Fi, which we call FDF-PIHD (Frequency Domain Fingerprint-based Passive Indoor Human Detection. Through this method, fine-grained physical layer Channel State Information (CSI can be extracted to generate feature fingerprints so as to help determine the state in the scene by matching online fingerprints with offline fingerprints. In order to improve accuracy, we combine the detection results of three receiving antennas to obtain the final test result. The experimental results show that the detection rates of our proposed scheme all reach above 90%, no matter whether the scene is human-free, stationary or a moving human presence. In addition, it can not only detect whether there is a target indoors, but also determine the current state of the target.

  8. Frequency modulation detection atomic force microscopy in the liquid environment

    Science.gov (United States)

    Jarvis, S. P.; Ishida, T.; Uchihashi, T.; Nakayama, Y.; Tokumoto, H.

    True atomic resolution imaging using frequency modulation detection is already well established in ultra-high vacuum. In this paper we demonstrate that it also has great potential in the liquid environment. Using a combination of magnetic activation and high-aspect-ratio carbon nanotube probes, we show that imaging can be readily combined with point spectroscopy, revealing both the tip-sample interaction and the structure of the intermediate liquid.

  9. Higher balance task demands are associated with an increase in individual alpha peak frequency

    Directory of Open Access Journals (Sweden)

    Thorben eHülsdünker

    2016-01-01

    Full Text Available Balance control is fundamental for most daily motor activities, and its impairment is associated with an increased risk of falling. Growing evidence suggests the human cortex is essentially contributing to the control of standing balance. However, the exact mechanisms remain unclear and need further investigation. In a previous study we introduced a new protocol to identify electrocortical activity associated with performance of different continuous balance tasks with the eyes opened. The aim of this study was to extend our previous results by investigating the individual alpha peak frequency (iAPF, a neurophysiological marker of thalamo-cortical information transmission, which remained unconsidered so far in balance research. Thirty-seven subjects completed nine balance tasks varying in surface stability and base of support. Electroencephalography (EEG was recorded from 32 scalp locations throughout balancing with the eyes closed to ensure reliable identification of the iAPF. Balance performance was quantified as the sum of anterior-posterior and medio-lateral movements of the supporting platform. The iAPF, as well as power in the theta, lower alpha and upper alpha frequency bands were determined for each balance task after applying an ICA-based artifact rejection procedure. Higher demands on balance control were associated with a global increase in iAPF and a decrease in lower alpha power. These results may indicate increased thalamo-cortical information transfer and general cortical activation, respectively. In addition, a significant increase in upper alpha activity was observed in the fronto-central region whereas it decreased in the centro-parietal region. Furthermore, midline theta increased with higher task demands probably indicating activation of error detection/processing mechanisms. IAPF as well as theta and alpha power were correlated with platform movements. The results provide new insights into spectral and spatial characteristics

  10. High frequency write head measurement with the phase detection magnetic force microscope

    International Nuclear Information System (INIS)

    Abe, M.; Tanaka, Y.

    2001-01-01

    We demonstrated the measurement of the high frequency (HF) magnetic field of a write head with the phase detection magnetic force microscope. An amplitude-modulated current was applied to the head coil to detect the force gradient induced by the HF magnetic field. Spatial resolution of this method was higher than that of the deflection detection method previously proposed. By the phase detection method, dynamic HF magnetic fields at the poles of the write heads were clearly imaged. HF magnetic field leakage was observed along the P2 pole shape on the air-bearing surface. The frequency dependence of the write head dynamics up to 350 MHz was also investigated. [copyright] 2001 American Institute of Physics

  11. Scheme for efficient extraction of low-frequency signal beyond the quantum limit by frequency-shift detection.

    Science.gov (United States)

    Yang, R G; Zhang, J; Zhai, Z H; Zhai, S Q; Liu, K; Gao, J R

    2015-08-10

    Low-frequency (Hz~kHz) squeezing is very important in many schemes of quantum precision measurement. But it is more difficult than that at megahertz-frequency because of the introduction of laser low-frequency technical noise. In this paper, we propose a scheme to obtain a low-frequency signal beyond the quantum limit from the frequency comb in a non-degenerate frequency and degenerate polarization optical parametric amplifier (NOPA) operating below threshold with type I phase matching by frequency-shift detection. Low-frequency squeezing immune to laser technical noise is obtained by a detection system with a local beam of two-frequency intense laser. Furthermore, the low-frequency squeezing can be used for phase measurement in Mach-Zehnder interferometer, and the signal-to-noise ratio (SNR) can be enhanced greatly.

  12. Change detection using landsat time series: A review of frequencies, preprocessing, algorithms, and applications

    Science.gov (United States)

    Zhu, Zhe

    2017-08-01

    The free and open access to all archived Landsat images in 2008 has completely changed the way of using Landsat data. Many novel change detection algorithms based on Landsat time series have been developed We present a comprehensive review of four important aspects of change detection studies based on Landsat time series, including frequencies, preprocessing, algorithms, and applications. We observed the trend that the more recent the study, the higher the frequency of Landsat time series used. We reviewed a series of image preprocessing steps, including atmospheric correction, cloud and cloud shadow detection, and composite/fusion/metrics techniques. We divided all change detection algorithms into six categories, including thresholding, differencing, segmentation, trajectory classification, statistical boundary, and regression. Within each category, six major characteristics of different algorithms, such as frequency, change index, univariate/multivariate, online/offline, abrupt/gradual change, and sub-pixel/pixel/spatial were analyzed. Moreover, some of the widely-used change detection algorithms were also discussed. Finally, we reviewed different change detection applications by dividing these applications into two categories, change target and change agent detection.

  13. Improved Detection of Vowel Envelope Frequency Following Responses Using Hotelling's T2 Analysis.

    Science.gov (United States)

    Vanheusden, Frederique J; Bell, Steven L; Chesnaye, Michael A; Simpson, David M

    2018-05-11

    were generated. Performance of the algorithms was assessed based on the number of sets for which a response could be detected at each SNR. In simulation studies, HT2_3F significantly outperformed the other algorithms when detecting a vowel stimulus in noise. For simulations containing responses only at a single frequency, HT2_3F performs worse compared with other approaches applied in this study as the additional frequencies included do not contain additional information. For recorded EEG data, HT2_MC showed a significantly higher response detection rate compared with MSC and FA-F-Test. Both HT2_MC and HT2_F0 also showed a significant reduction in detection time compared with the FA-F-Test algorithm. Comparisons between different electrode locations confirmed a higher number of detections for electrodes close to Cz compared to more peripheral locations. The HT2 method is more sensitive than FA-F-Test and MSC in detecting responses to complex stimuli because it allows detection of multiple frequencies (HT2_F3) and multiple EEG channels (HT2_MC) simultaneously. This effect was shown in simulation studies for HT2_3F and in EEG data for the HT2_MC algorithm. The spread in detection time across subjects is also lower for the HT2 algorithm, with decision on the presence of an eFFR possible within 5 min.

  14. PageRank for low frequency earthquake detection

    Science.gov (United States)

    Aguiar, A. C.; Beroza, G. C.

    2013-12-01

    We have analyzed Hi-Net seismic waveform data during the April 2006 tremor episode in the Nankai Trough in SW Japan using the autocorrelation approach of Brown et al. (2008), which detects low frequency earthquakes (LFEs) based on pair-wise waveform matching. We have generalized this to exploit the fact that waveforms may repeat multiple times, on more than just a pair-wise basis. We are working towards developing a sound statistical basis for event detection, but that is complicated by two factors. First, the statistical behavior of the autocorrelations varies between stations. Analyzing one station at a time assures that the detection threshold will only depend on the station being analyzed. Second, the positive detections do not satisfy "closure." That is, if window A correlates with window B, and window B correlates with window C, then window A and window C do not necessarily correlate with one another. We want to evaluate whether or not a linked set of windows are correlated due to chance. To do this, we map our problem on to one that has previously been solved for web search, and apply Google's PageRank algorithm. PageRank is the probability of a 'random surfer' to visit a particular web page; it assigns a ranking for a webpage based on the amount of links associated with that page. For windows of seismic data instead of webpages, the windows with high probabilities suggest likely LFE signals. Once identified, we stack the matched windows to improve the snr and use these stacks as template signals to find other LFEs within continuous data. We compare the results among stations and declare a detection if they are found in a statistically significant number of stations, based on multinomial statistics. We compare our detections using the single-station method to detections found by Shelly et al. (2007) for the April 2006 tremor sequence in Shikoku, Japan. We find strong similarity between the results, as well as many new detections that were not found using

  15. Tsunami Arrival Detection with High Frequency (HF Radar

    Directory of Open Access Journals (Sweden)

    Donald Barrick

    2012-05-01

    Full Text Available Quantitative real-time observations of a tsunami have been limited to deep-water, pressure-sensor observations of changes in the sea surface elevation and observations of sea level fluctuations at the coast, which are essentially point measurements. Constrained by these data, models have been used for predictions and warning of the arrival of a tsunami, but to date no system exists for local detection of an actual incoming wave with a significant warning capability. Networks of coastal high frequency (HF-radars are now routinely observing surface currents in many countries. We report here on an empirical method for the detection of the initial arrival of a tsunami, and demonstrate its use with results from data measured by fourteen HF radar sites in Japan and USA following the magnitude 9.0 earthquake off Sendai, Japan, on 11 March 2011. The distance offshore at which the tsunami can be detected, and hence the warning time provided, depends on the bathymetry: the wider the shallow continental shelf, the greater this time. We compare arrival times at the radars with those measured by neighboring tide gauges. Arrival times measured by the radars preceded those at neighboring tide gauges by an average of 19 min (Japan and 15 min (USA The initial water-height increase due to the tsunami as measured by the tide gauges was moderate, ranging from 0.3 to 2 m. Thus it appears possible to detect even moderate tsunamis using this method. Larger tsunamis could obviously be detected further from the coast. We find that tsunami arrival within the radar coverage area can be announced 8 min (i.e., twice the radar spectral time resolution after its first appearance. This can provide advance warning of the tsunami approach to the coastline locations.

  16. Reducing Undue Conservatism in "Higher Frequency" Structural Design Loads in Aerospace Components

    Science.gov (United States)

    Knight, J. Brent

    2012-01-01

    This study is intended to investigate the frequency dependency of significant strain due to vibratory loads in aerospace vehicle components. The notion that "higher frequency" dynamic loads applied as static loads is inherently conservative is perceived as widely accepted. This effort is focused on demonstrating that principle and attempting to evolve methods to capitalize on it to mitigate undue conservatism. It has been suggested that observations of higher frequency modes that resulted in very low corresponding strain did so due to those modes not being significant. Two avionics boxes, one with its first significant mode at 341 Hz and the other at 857 Hz, were attached to a flat panel installed on a curved orthogrid panel which was driven acoustically in tests performed at NASA/MSFC. Strain and acceleration were measured at select locations on each of the boxes. When possible, strain gage rosettes and accelerometers were installed on either side of a given structural member so that measured strain and acceleration data would directly correspond to one another. Ultimately, a frequency above which vibratory loads can be disregarded for purposes of static structural analyses and sizing of typical robust aerospace components is sought.

  17. Species With Greater Aerial Maneuverability Have Higher Frequency of Collisions With Aircraft: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Esteban Fernández-Juricic

    2018-03-01

    Full Text Available Antipredator responses may appear unsuccessful when animals are exposed to approaching vehicles, often resulting in mortality. Recent studies have addressed whether certain biological traits are associated with variation in collision risk with cars, but not with higher speed-vehicles like aircraft. Our goal was to establish the association between different species traits (i.e., body mass, eye size, brain size, wing loading, wing aspect ratio and the frequency of bird collisions with aircraft (hereafter, bird strikes using a comparative approach controlling for the effects of shared ancestry. We proposed directional predictions as to how each of the species traits would affect the frequency of bird strikes. Considering 39 bird species with all traits represented, the model containing wing loading had the best fit to account for the variance in bird strikes across species. In another model with 54 species exploring the fit to different polynomial models but considering only wing loading, we found that wing loading was negatively and linearly associated with the frequency of bird strikes. Counterintuitively, species with lower wing loading (hence, greater maneuverability had a higher frequency of bird strikes. We discuss potential non-mutually exclusive explanations (e.g., high wing loading species fly faster, thus gaining some extra time to avoid the aircraft flight path; high wing loading species are hazed more intensively at airports, which could lower collisions, etc.. Ultimately, our findings uncovered that species with low wing loading get struck at a higher rate at airports, which reduces the safety risk for humans because these species tend not to cause damaging strikes, but the ecological consequences of their potentially higher local mortality are unknown.

  18. The effect of electric field maximum on the Rabi flopping and generated higher frequency spectra

    International Nuclear Information System (INIS)

    Niu Yueping; Cui Ni; Xiang Yang; Li Ruxin; Gong Shangqing; Xu Zhizhan

    2008-01-01

    We investigate the effect of the electric field maximum on the Rabi flopping and the generated higher frequency spectra properties by solving Maxwell-Bloch equations without invoking any standard approximations. It is found that the maximum of the electric field will lead to carrier-wave Rabi flopping (CWRF) through reversion dynamics which will be more evident when the applied field enters the sub-one-cycle regime. Therefore, under the interaction of sub-one-cycle pulses, the Rabi flopping follows the transient electric field tightly through the oscillation and reversion dynamics, which is in contrast to the conventional envelope Rabi flopping. Complete or incomplete population inversion can be realized through the control of the carrier-envelope phase (CEP). Furthermore, the generated higher frequency spectra will be changed from distinct to continuous or irregular with the variation of the CEP. Our results demonstrate that due to the evident maximum behavior of the electric field, pulses with different CEP give rise to different CWRFs, and then different degree of interferences lead to different higher frequency spectral features.

  19. Aircraft Fault Detection Using Real-Time Frequency Response Estimation

    Science.gov (United States)

    Grauer, Jared A.

    2016-01-01

    A real-time method for estimating time-varying aircraft frequency responses from input and output measurements was demonstrated. The Bat-4 subscale airplane was used with NASA Langley Research Center's AirSTAR unmanned aerial flight test facility to conduct flight tests and collect data for dynamic modeling. Orthogonal phase-optimized multisine inputs, summed with pilot stick and pedal inputs, were used to excite the responses. The aircraft was tested in its normal configuration and with emulated failures, which included a stuck left ruddervator and an increased command path latency. No prior knowledge of a dynamic model was used or available for the estimation. The longitudinal short period dynamics were investigated in this work. Time-varying frequency responses and stability margins were tracked well using a 20 second sliding window of data, as compared to a post-flight analysis using output error parameter estimation and a low-order equivalent system model. This method could be used in a real-time fault detection system, or for other applications of dynamic modeling such as real-time verification of stability margins during envelope expansion tests.

  20. Comparing the effects of age on amplitude modulation and frequency modulation detection.

    Science.gov (United States)

    Wallaert, Nicolas; Moore, Brian C J; Lorenzi, Christian

    2016-06-01

    Frequency modulation (FM) and amplitude modulation (AM) detection thresholds were measured at 40 dB sensation level for young (22-28 yrs) and older (44-66 yrs) listeners with normal audiograms for a carrier frequency of 500 Hz and modulation rates of 2 and 20 Hz. The number of modulation cycles, N, varied between 2 and 9. For FM detection, uninformative AM at the same rate as the FM was superimposed to disrupt excitation-pattern cues. For both groups, AM and FM detection thresholds were lower for the 2-Hz than for the 20-Hz rate, and AM and FM detection thresholds decreased with increasing N. Thresholds were higher for older than for younger listeners, especially for FM detection at 2 Hz, possibly reflecting the effect of age on the use of temporal-fine-structure cues for 2-Hz FM detection. The effect of increasing N was similar across groups for both AM and FM. However, at 20 Hz, older listeners showed a greater effect of increasing N than younger listeners for both AM and FM. The results suggest that ageing reduces sensitivity to both excitation-pattern and temporal-fine-structure cues for modulation detection, but more so for the latter, while sparing temporal integration of these cues at low modulation rates.

  1. The detection of higher-order acoustic transitions is reflected in the N1 ERP.

    Science.gov (United States)

    Weise, Annekathrin; Schröger, Erich; Horváth, János

    2018-01-30

    The auditory system features various types of dedicated change detectors enabling the rapid parsing of auditory stimulation into distinct events. The activity of such detectors is reflected by the N1 ERP. Interestingly, certain acoustic transitions show an asymmetric N1 elicitation pattern: whereas first-order transitions (e.g., a change from a segment of constant frequency to a frequency glide [c-to-g change]) elicit N1, higher-order transitions (e.g., glide-to-constant [g-to-c] changes) do not. Consensus attributes this asymmetry to the absence of any available sensory mechanism that is able to rapidly detect higher-order changes. In contrast, our study provides compelling evidence for such a mechanism. We collected electrophysiological and behavioral data in a transient-detection paradigm. In each condition, a random (50%-50%) sequence of two types of tones occurred, which did or did not contain a transition (e.g., c-to-g and constant stimuli or g-to-c and glide tones). Additionally, the rate of pitch change of the glide varied (i.e., 10 vs. 40 semitones per second) in order to increase the number of responding neural assemblies. The rate manipulation modulated transient ERPs and behavioral detection performance for g-to-c transitions much stronger than for c-to-g transitions. The topographic and tomographic analyses suggest that the N1 response to c-to-g and also to g-to-c transitions emerged from the superior temporal gyrus. This strongly supports a sensory mechanism that allows the fast detection of higher-order changes. © 2018 Society for Psychophysiological Research.

  2. Object Categorization in Finer Levels Relies More on Higher Spatial Frequencies and Takes Longer.

    Science.gov (United States)

    Ashtiani, Matin N; Kheradpisheh, Saeed R; Masquelier, Timothée; Ganjtabesh, Mohammad

    2017-01-01

    advantage of the superordinate (resp. basic) level to basic (resp. subordinate) level is mainly due to the computational constraints (the visual system processes higher spatial frequencies more slowly, and categorization in finer levels depends more on these higher spatial frequencies).

  3. HIGHER MODE FREQUENCY EFFECTS ON RESONANCE IN MACHINERY, STRUCTURES, AND PIPE SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Leishear, R.

    2010-05-02

    The complexities of resonance in multi-degree of freedom systems (multi-DOF) may be clarified using graphic presentations. Multi-DOF systems represent actual systems, such as beams or springs, where multiple, higher order, natural frequencies occur. Resonance occurs when a cyclic load is applied to a structure, and the frequency of the applied load equals one of the natural frequencies. Both equations and graphic presentations are available in the literature for single degree of freedom (SDOF) systems, which describe the response of spring-mass-damper systems to harmonically applied, or cyclic, loads. Loads may be forces, moments, or forced displacements applied to one end of a structure. Multi-DOF systems are typically described only by equations in the literature, and while equations certainly permit a case by case analysis for specific conditions, graphs provide an overall comprehension not gleaned from single equations. In fact, this collection of graphed equations provides novel results, which describe the interactions between multiple natural frequencies, as well as a comprehensive description of increased vibrations near resonance.

  4. Analysis of Higher Order Modes in Large Superconducting Radio Frequency Accelerating Structures

    CERN Document Server

    Galek, Tomasz; Brackebusch, Korinna; Van Rienen, Ursula

    2015-01-01

    Superconducting radio frequency cavities used for accelerating charged particle beams are commonly used in accelerator facilities around the world. The design and optimization of modern superconducting RF cavities requires intensive numerical simulations. Vast number of operational parameters must be calculated to ensure appropriate functioning of the accelerating structures. In this study, we primarily focus on estimation and behavior of higher order modes in superconducting RF cavities connected in chains. To calculate large RF models the state-space concatenation scheme, an efficient hybrid method, is employed.

  5. Wideband Radio Frequency Interference Detection for Microwave Radiometer Subsystem

    Data.gov (United States)

    National Aeronautics and Space Administration — Anthropogenic Radio-Frequency Interference (RFI) is threatening the quality and utility of multi-frequency passive microwave radiometry. The GPM Microwave Imager...

  6. Squeezed light for the interferometric detection of high-frequency gravitational waves

    Science.gov (United States)

    Schnabel, R.; Harms, J.; Strain, K. A.; Danzmann, K.

    2004-03-01

    The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 106dB/20dB ap 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 × 10-23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity.

  7. Squeezed light for the interferometric detection of high-frequency gravitational waves

    International Nuclear Information System (INIS)

    Schnabel, R; Harms, J; Strain, K A; Danzmann, K

    2004-01-01

    The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 10 6dB/20dB ∼ 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 x 10 -23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity

  8. Higher moments method for generalized Pareto distribution in flood frequency analysis

    Science.gov (United States)

    Zhou, C. R.; Chen, Y. F.; Huang, Q.; Gu, S. H.

    2017-08-01

    The generalized Pareto distribution (GPD) has proven to be the ideal distribution in fitting with the peak over threshold series in flood frequency analysis. Several moments-based estimators are applied to estimating the parameters of GPD. Higher linear moments (LH moments) and higher probability weighted moments (HPWM) are the linear combinations of Probability Weighted Moments (PWM). In this study, the relationship between them will be explored. A series of statistical experiments and a case study are used to compare their performances. The results show that if the same PWM are used in LH moments and HPWM methods, the parameter estimated by these two methods is unbiased. Particularly, when the same PWM are used, the PWM method (or the HPWM method when the order equals 0) shows identical results in parameter estimation with the linear Moments (L-Moments) method. Additionally, this phenomenon is significant when r ≥ 1 that the same order PWM are used in HPWM and LH moments method.

  9. Method of detecting system function by measuring frequency response

    Science.gov (United States)

    Morrison, John L [Butte, MT; Morrison, William H [Manchester, CT; Christophersen, Jon P [Idaho Falls, ID

    2012-04-03

    Real-time battery impedance spectrum is acquired using a one-time record. Fast Summation Transformation (FST) is a parallel method of acquiring a real-time battery impedance spectrum using a one-time record that enables battery diagnostics. An excitation current to a battery is a sum of equal amplitude sine waves of frequencies that are octave harmonics spread over a range of interest. A sample frequency is also octave and harmonically related to all frequencies in the sum. The time profile of this signal has a duration that is a few periods of the lowest frequency. The voltage response of the battery, average deleted, is the impedance of the battery in the time domain. Since the excitation frequencies are known and octave and harmonically related, a simple algorithm, FST, processes the time record by rectifying relative to the sine and cosine of each frequency. Another algorithm yields real and imaginary components for each frequency.

  10. Method of detecting system function by measuring frequency response

    Science.gov (United States)

    Morrison, John L.; Morrison, William H.; Christophersen, Jon P.; Motloch, Chester G.

    2013-01-08

    Methods of rapidly measuring an impedance spectrum of an energy storage device in-situ over a limited number of logarithmically distributed frequencies are described. An energy storage device is excited with a known input signal, and a response is measured to ascertain the impedance spectrum. An excitation signal is a limited time duration sum-of-sines consisting of a select number of frequencies. In one embodiment, magnitude and phase of each frequency of interest within the sum-of-sines is identified when the selected frequencies and sample rate are logarithmic integer steps greater than two. This technique requires a measurement with a duration of one period of the lowest frequency. In another embodiment, where selected frequencies are distributed in octave steps, the impedance spectrum can be determined using a captured time record that is reduced to a half-period of the lowest frequency.

  11. Frequency-agile THz-wave generation and detection system using nonlinear frequency conversion at room temperature.

    Science.gov (United States)

    Guo, Ruixiang; Ikar'i, Tomofumi; Zhang, Jun; Minamide, Hiroaki; Ito, Hiromasa

    2010-08-02

    A surface-emitting THz parametric oscillator is set up to generate a narrow-linewidth, nanosecond pulsed THz-wave radiation. The THz-wave radiation is coherently detected using the frequency up-conversion in MgO: LiNbO(3) crystal. Fast frequency tuning and automatic achromatic THz-wave detection are achieved through a special optical design, including a variable-angle mirror and 1:1 telescope devices in the pump and THz-wave beams. We demonstrate a frequency-agile THz-wave parametric generation and THz-wave coherent detection system. This system can be used as a frequency-domain THz-wave spectrometer operated at room-temperature, and there are a high possible to develop into a real-time two-dimensional THz spectral imaging system.

  12. Coherent radio-frequency detection for narrowband direct comb spectroscopy.

    Science.gov (United States)

    Anstie, James D; Perrella, Christopher; Light, Philip S; Luiten, Andre N

    2016-02-22

    We demonstrate a scheme for coherent narrowband direct optical frequency comb spectroscopy. An extended cavity diode laser is injection locked to a single mode of an optical frequency comb, frequency shifted, and used as a local oscillator to optically down-mix the interrogating comb on a fast photodetector. The high spectral coherence of the injection lock generates a microwave frequency comb at the output of the photodiode with very narrow features, enabling spectral information to be further down-mixed to RF frequencies, allowing optical transmittance and phase to be obtained using electronics commonly found in the lab. We demonstrate two methods for achieving this step: a serial mode-by-mode approach and a parallel dual-comb approach, with the Cs D1 transition at 894 nm as a test case.

  13. Detection of High Frequency Oscillations by Hybrid Depth Electrodes in Standard Clinical Intracranial EEG Recordings

    Directory of Open Access Journals (Sweden)

    Efstathios D Kondylis

    2014-08-01

    Full Text Available High frequency oscillations (HFOs have been proposed as a novel marker for epileptogenic tissue, spurring tremendous research interest into the characterization of these transient events. A wealth of continuously recorded intracranial electroencephalographic (iEEG data is currently available from patients undergoing invasive monitoring for the surgical treatment of epilepsy. In contrast to data recorded on research-customized recording systems, data from clinical acquisition systems remain an underutilized resource for HFO detection in most centers. The effective and reliable use of this clinically obtained data would be an important advance in the ongoing study of HFOs and their relationship to ictogenesis. The diagnostic utility of HFOs ultimately will be limited by the ability of clinicians to detect these brief, sporadic, and low amplitude events in an electrically noisy clinical environment. Indeed, one of the most significant factors limiting the use of such clinical recordings for research purposes is their low signal to noise ratio, especially in the higher frequency bands. In order to investigate the presence of HFOs in clinical data, we first obtained continuous intracranial recordings in a typical clinical environment using a commercially available, commonly utilized data acquisition system and off the shelf hybrid macro/micro depth electrodes. This data was then inspected for the presence of HFOs using semi-automated methods and expert manual review. With targeted removal of noise frequency content, HFOs were detected on both macro- and micro-contacts, and preferentially localized to seizure onset zones. HFOs detected by the offline, semi-automated method were also validated in the clinical viewer, demonstrating that 1 this clinical system allows for the visualization of HFOs, and 2 with effective signal processing, clinical recordings can yield valuable information for offline analysis.

  14. Investigating strength and frequency effects in recognition memory using type-2 signal detection theory.

    Science.gov (United States)

    Higham, Philip A; Perfect, Timothy J; Bruno, Davide

    2009-01-01

    Criterion- versus distribution-shift accounts of frequency and strength effects in recognition memory were investigated with Type-2 signal detection receiver operating characteristic (ROC) analysis, which provides a measure of metacognitive monitoring. Experiment 1 demonstrated a frequency-based mirror effect, with a higher hit rate and lower false alarm rate, for low frequency words compared with high frequency words. In Experiment 2, the authors manipulated item strength with repetition, which showed an increased hit rate but no effect on the false alarm rate. Whereas Type-1 indices were ambiguous as to whether these effects were based on a criterion- or distribution-shift model, the two models predict opposite effects on Type-2 distractor monitoring under some assumptions. Hence, Type-2 ROC analysis discriminated between potential models of recognition that could not be discriminated using Type-1 indices alone. In Experiment 3, the authors manipulated Type-1 response bias by varying the number of old versus new response categories to confirm the assumptions made in Experiments 1 and 2. The authors conclude that Type-2 analyses are a useful tool for investigating recognition memory when used in conjunction with more traditional Type-1 analyses.

  15. Development of radio frequency interference detection algorithms for passive microwave remote sensing

    Science.gov (United States)

    Misra, Sidharth

    Radio Frequency Interference (RFI) signals are man-made sources that are increasingly plaguing passive microwave remote sensing measurements. RFI is of insidious nature, with some signals low power enough to go undetected but large enough to impact science measurements and their results. With the launch of the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite in November 2009 and the upcoming launches of the new NASA sea-surface salinity measuring Aquarius mission in June 2011 and soil-moisture measuring Soil Moisture Active Passive (SMAP) mission around 2015, active steps are being taken to detect and mitigate RFI at L-band. An RFI detection algorithm was designed for the Aquarius mission. The algorithm performance was analyzed using kurtosis based RFI ground-truth. The algorithm has been developed with several adjustable location dependant parameters to control the detection statistics (false-alarm rate and probability of detection). The kurtosis statistical detection algorithm has been compared with the Aquarius pulse detection method. The comparative study determines the feasibility of the kurtosis detector for the SMAP radiometer, as a primary RFI detection algorithm in terms of detectability and data bandwidth. The kurtosis algorithm has superior detection capabilities for low duty-cycle radar like pulses, which are more prevalent according to analysis of field campaign data. Most RFI algorithms developed have generally been optimized for performance with individual pulsed-sinusoidal RFI sources. A new RFI detection model is developed that takes into account multiple RFI sources within an antenna footprint. The performance of the kurtosis detection algorithm under such central-limit conditions is evaluated. The SMOS mission has a unique hardware system, and conventional RFI detection techniques cannot be applied. Instead, an RFI detection algorithm for SMOS is developed and applied in the angular domain. This algorithm compares

  16. Detection of Dew-Point by substantial Raman Band Frequency Jumps (A new Method)

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

    Detection of Dew-Point by substantial Raman Band Frequency Jumps (A new Method). See poster at http://www.kemi.dtu.dk/~ajo/rolf/jumps.pdf......Detection of Dew-Point by substantial Raman Band Frequency Jumps (A new Method). See poster at http://www.kemi.dtu.dk/~ajo/rolf/jumps.pdf...

  17. Structural damage detection using higher-order finite elements and a scanning laser vibrometer

    Science.gov (United States)

    Jin, Si

    In contrast to conventional non-destructive evaluation methods, dynamics-based damage detection methods are capable of rapid integrity evaluation of large structures and have received considerable attention from aerospace, mechanical, and civil engineering communities in recent years. However, the identifiable damage size using dynamics-based methods is determined by the number of sensors used, level of measurement noise, accuracy of structural models, and signal processing techniques. In this thesis we study dynamics of structures with damage and then derive and experimentally verify new model-independent structural damage detection methods that can locate small damage to structures. To find sensitive damage detection parameters we develop a higher-order beam element that enforces the continuity of displacements, slopes, bending moments, and shear forces at all nodes, and a higher-order rectangular plate element that enforces the continuity of displacements, slopes, and bending and twisting moments at all nodes. These two elements are used to study the dynamics of beams and plates. Results show that high-order spatial derivatives of high-frequency modes are important sensitive parameters that can locate small structural damage. Unfortunately the most powerful and popular structural modeling technique, the finite element method, is not accurate in predicting high-frequency responses. Hence, a model-independent method using dynamic responses obtained from high density measurements is concluded to be the best approach. To increase measurement density and reduce noise a Polytec PI PSV-200 scanning laser vibrometer is used to provide non-contact, dense, and accurate measurements of structural vibration velocities. To avoid the use of structural models and to extract sensitive detection parameters from experimental data, a brand-new structural damage detection method named BED (Boundary-Effect Detection) is developed for pinpointing damage locations using Operational

  18. Robust detection of discordant sites in regional frequency analysis

    NARCIS (Netherlands)

    Neykov, N.M.; Neytchev, P.N.; Van Gelder, P.H.A.J.M.; Todorov, V.K.

    2007-01-01

    The discordancy measure in terms of the sample L?moment ratios (L?CV, L?skewness, L?kurtosis) of the at?site data is widely recommended in the screening process of atypical sites in the regional frequency analysis (RFA). The sample mean and the covariance matrix of the L?moments ratios, on which the

  19. Detection performance improvement of FMCW radar using frequency shift

    NARCIS (Netherlands)

    Wu, Y.; Linnartz, J.P.M.G.

    2011-01-01

    Frequency modulated continuous wave (FMCW) radars have been widely used for measuring target range and speed. In this paper, we present a mathematical model that quantifies the system-level performance of FMCW radar systems. In FMCW radar, the target range is measured through measuring the beat

  20. Rapid Fear Detection Relies on High Spatial Frequencies

    NARCIS (Netherlands)

    Stein, T.; Seymour, K.; Hebart, M.N.; Sterzer, P.

    Signals of threat—such as fearful faces—are processed with priority and have privileged access to awareness. This fear advantage is commonly believed to engage a specialized subcortical pathway to the amygdala that bypasses visual cortex and processes predominantly low-spatial-frequency information

  1. Extending the ICRF to Higher Radio Frequencies: 24 and 43 GHz Astrometry

    Science.gov (United States)

    Jacobs, Christopher S.; Charlot, Patrick; Fomalont, Ed B.; Gordon, David; Lanyi, Gabor E.; Ma, Chopo; Naudet, Charles J.; Sovers, Ojars J.; Zhang, Liwei D.; Kq VLBI Survey Collaboration

    2004-06-01

    Celestial reference frames have been constructed at K-band (24 GHz) and Q-band (43 GHz) based on VLBI astrometric survey observations of active galactic nuclei. Five VLBA observing sessions covered the full 24 hours of right ascension and declinations down to -44°. K-band's 230 sources have median formal position uncertainties of 150 and 290 μas in α cos δ and δ, respectively; the corresponding uncertainties for 132 Q-band sources are 215 and 360 μas, respectively. K-band weighted RMS (WRMS) residuals were 33 ps and 48 fs/s in delay and rate, respectively. Comparison of the K-band frame to the S/X-band ICRF shows WRMS agreement of 330 and 590 μas in α cos δ and δ, respectively. The motivations for extending the ICRF to higher frequencies are to use more compact sources to construct a more stable frame, to provide phase calibrators, and to support spacecraft navigation at Ka-band.

  2. Quench detection on a superconducting radio-frequency cavity

    OpenAIRE

    Lai, Ru-Yu; Spirn, Daniel

    2017-01-01

    We study quench detection in superconducting accelerator cavities cooled with He-II. A rigorous mathematical formula is derived to localize the quench position from dynamical data over a finite time interval at a second sound detector.

  3. A High-Precision Time-Frequency Entropy Based on Synchrosqueezing Generalized S-Transform Applied in Reservoir Detection

    Directory of Open Access Journals (Sweden)

    Hui Chen

    2018-06-01

    Full Text Available According to the fact that high frequency will be abnormally attenuated when seismic signals travel across reservoirs, a new method, which is named high-precision time-frequency entropy based on synchrosqueezing generalized S-transform, is proposed for hydrocarbon reservoir detection in this paper. First, the proposed method obtains the time-frequency spectra by synchrosqueezing generalized S-transform (SSGST, which are concentrated around the real instantaneous frequency of the signals. Then, considering the characteristics and effects of noises, we give a frequency constraint condition to calculate the entropy based on time-frequency spectra. The synthetic example verifies that the entropy will be abnormally high when seismic signals have an abnormal attenuation. Besides, comparing with the GST time-frequency entropy and the original SSGST time-frequency entropy in field data, the results of the proposed method show higher precision. Moreover, the proposed method can not only accurately detect and locate hydrocarbon reservoirs, but also effectively suppress the impact of random noises.

  4. Pattern-Directed Attention in Uncertain Frequency Detection.

    Science.gov (United States)

    1983-10-14

    performance when compared to a single frequency condition even if the listeners are aware that more than one signal can occur ( Creelman , 1960; Green...be missed. On the-other hand, the multiple band approach, introduced by Green (1958) and modified by Creelman (1960), assumes that listeners base...multiple-band approaches ( Creelman , 1960; Green, 1961; Macmillan & Schwartz, 1975). In general, the two views are difficult to distinguish empirically, and

  5. Across frequency processes involved in auditory detection of coloration

    DEFF Research Database (Denmark)

    Buchholz, Jörg; Kerketsos, P

    2008-01-01

    filterbank was designed to approximate auditory filter-shapes measured by Oxenham and Shera [JARO, 2003, 541-554], derived from forward masking data. The results of the present study demonstrate that a “purely” spectrum-based model approach can successfully describe auditory coloration detection even at high......When an early wall reflection is added to a direct sound, a spectral modulation is introduced to the signal's power spectrum. This spectral modulation typically produces an auditory sensation of coloration or pitch. Throughout this study, auditory spectral-integration effects involved in coloration...... detection are investigated. Coloration detection thresholds were therefore measured as a function of reflection delay and stimulus bandwidth. In order to investigate the involved auditory mechanisms, an auditory model was employed that was conceptually similar to the peripheral weighting model [Yost, JASA...

  6. Higher Eating Frequency Does Not Decrease Appetite in Healthy Adults12

    Science.gov (United States)

    Perrigue, Martine M; Drewnowski, Adam; Wang, Ching-Yun; Neuhouser, Marian L

    2016-01-01

    Background: Consumption of small, frequent meals is suggested as an effective approach to control appetite and food intake and might be a strategy for weight loss or healthy weight maintenance. Despite much speculation on the topic, scientific evidence is limited to support such a relation in the absence of changes to diet composition. Objective: We examined the effects of high compared with low eating frequency (EF) on self-reported appetite as a secondary outcome in a controlled trial. Methods: We conducted a randomized, crossover intervention trial in 12 participants (4 men, 8 women) who completed 2 isocaloric 3-wk intervention phases of low EF (3 eating occasions/d) compared with high EF (8 eating occasions/d). On the last morning of each study phase, participants completed a 4-h appetite testing session. During the appetite testing session, participants completing the low EF phase consumed a meal at 0800. Participants completing the high EF intervention consumed the same meal spread evenly over 2 eating occasions at 0800 and 1030. Standardized ratings of hunger, desire to eat, fullness, thirst, and nausea were completed every 30 min with the use of paper-and-pencil semianchored 100-mm visual analog scales. A composite appetite score was calculated as the mean of hunger, desire to eat, and the inverse of fullness (calculated as 100-fullness rating). Linear regression analysis compared ratings between low EF and high EF conditions. Results: The mean composite appetite score was higher in the high EF condition for the total testing period (baseline through 1200) (P appetite. This trial was registered at clinicaltrials.gov as NCT02548026. PMID:26561409

  7. FLEAD: online frequency likelihood estimation anomaly detection for mobile sensing

    NARCIS (Netherlands)

    Le Viet Duc, L Duc; Scholten, Johan; Havinga, Paul J.M.

    With the rise of smartphone platforms, adaptive sensing becomes an predominant key to overcome intricate constraints such as smartphone's capabilities and dynamic data. One way to do this is estimating the event probability based on anomaly detection to invoke heavy processes, such as switching on

  8. Small Displacement Detection of Biological Signals Using the Cyclic Frequency Method

    Directory of Open Access Journals (Sweden)

    Dan Zhang

    2015-01-01

    Full Text Available A new signal processing method called the Cyclic Frequency method is proposed for small displacement detection of vital signals such as heart rate and respiration using the CW radar method. We have presented experimental results of small displacement detection to confirm the validity of the method. The displacement amplitude 2.5 mm can be detected with a propagation frequency of 24.15 GHz. We may increase the propagation frequency for smaller displacement amplitude or target velocity.

  9. Focus: Two-dimensional electron-electron double resonance and molecular motions: The challenge of higher frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Franck, John M.; Chandrasekaran, Siddarth; Dzikovski, Boris; Dunnam, Curt R.; Freed, Jack H., E-mail: jhf3@cornell.edu [Department of Chemistry and Chemical Biology and National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York 14853 (United States)

    2015-06-07

    The development, applications, and current challenges of the pulsed ESR technique of two-dimensional Electron-Electron Double Resonance (2D ELDOR) are described. This is a three-pulse technique akin to 2D Exchange Nuclear Magnetic Resonance, but involving electron spins, usually in the form of spin-probes or spin-labels. As a result, it required the extension to much higher frequencies, i.e., microwaves, and much faster time scales, with π/2 pulses in the 2-3 ns range. It has proven very useful for studying molecular dynamics in complex fluids, and spectral results can be explained by fitting theoretical models (also described) that provide a detailed analysis of the molecular dynamics and structure. We discuss concepts that also appear in other forms of 2D spectroscopy but emphasize the unique advantages and difficulties that are intrinsic to ESR. Advantages include the ability to tune the resonance frequency, in order to probe different motional ranges, while challenges include the high ratio of the detection dead time vs. the relaxation times. We review several important 2D ELDOR studies of molecular dynamics. (1) The results from a spin probe dissolved in a liquid crystal are followed throughout the isotropic → nematic → liquid-like smectic → solid-like smectic → crystalline phases as the temperature is reduced and are interpreted in terms of the slowly relaxing local structure model. Here, the labeled molecule is undergoing overall motion in the macroscopically aligned sample, as well as responding to local site fluctuations. (2) Several examples involving model phospholipid membranes are provided, including the dynamic structural characterization of the boundary lipid that coats a transmembrane peptide dimer. Additionally, subtle differences can be elicited for the phospholipid membrane phases: liquid disordered, liquid ordered, and gel, and the subtle effects upon the membrane, of antigen cross-linking of receptors on the surface of plasma membrane

  10. Focus: Two-dimensional electron-electron double resonance and molecular motions: The challenge of higher frequencies

    International Nuclear Information System (INIS)

    Franck, John M.; Chandrasekaran, Siddarth; Dzikovski, Boris; Dunnam, Curt R.; Freed, Jack H.

    2015-01-01

    The development, applications, and current challenges of the pulsed ESR technique of two-dimensional Electron-Electron Double Resonance (2D ELDOR) are described. This is a three-pulse technique akin to 2D Exchange Nuclear Magnetic Resonance, but involving electron spins, usually in the form of spin-probes or spin-labels. As a result, it required the extension to much higher frequencies, i.e., microwaves, and much faster time scales, with π/2 pulses in the 2-3 ns range. It has proven very useful for studying molecular dynamics in complex fluids, and spectral results can be explained by fitting theoretical models (also described) that provide a detailed analysis of the molecular dynamics and structure. We discuss concepts that also appear in other forms of 2D spectroscopy but emphasize the unique advantages and difficulties that are intrinsic to ESR. Advantages include the ability to tune the resonance frequency, in order to probe different motional ranges, while challenges include the high ratio of the detection dead time vs. the relaxation times. We review several important 2D ELDOR studies of molecular dynamics. (1) The results from a spin probe dissolved in a liquid crystal are followed throughout the isotropic → nematic → liquid-like smectic → solid-like smectic → crystalline phases as the temperature is reduced and are interpreted in terms of the slowly relaxing local structure model. Here, the labeled molecule is undergoing overall motion in the macroscopically aligned sample, as well as responding to local site fluctuations. (2) Several examples involving model phospholipid membranes are provided, including the dynamic structural characterization of the boundary lipid that coats a transmembrane peptide dimer. Additionally, subtle differences can be elicited for the phospholipid membrane phases: liquid disordered, liquid ordered, and gel, and the subtle effects upon the membrane, of antigen cross-linking of receptors on the surface of plasma membrane

  11. An autocorrelation method to detect low frequency earthquakes within tremor

    Science.gov (United States)

    Brown, J.R.; Beroza, G.C.; Shelly, D.R.

    2008-01-01

    Recent studies have shown that deep tremor in the Nankai Trough under western Shikoku consists of a swarm of low frequency earthquakes (LFEs) that occur as slow shear slip on the down-dip extension of the primary seismogenic zone of the plate interface. The similarity of tremor in other locations suggests a similar mechanism, but the absence of cataloged low frequency earthquakes prevents a similar analysis. In this study, we develop a method for identifying LFEs within tremor. The method employs a matched-filter algorithm, similar to the technique used to infer that tremor in parts of Shikoku is comprised of LFEs; however, in this case we do not assume the origin times or locations of any LFEs a priori. We search for LFEs using the running autocorrelation of tremor waveforms for 6 Hi-Net stations in the vicinity of the tremor source. Time lags showing strong similarity in the autocorrelation represent either repeats, or near repeats, of LFEs within the tremor. We test the method on an hour of Hi-Net recordings of tremor and demonstrates that it extracts both known and previously unidentified LFEs. Once identified, we cross correlate waveforms to measure relative arrival times and locate the LFEs. The results are able to explain most of the tremor as a swarm of LFEs and the locations of newly identified events appear to fill a gap in the spatial distribution of known LFEs. This method should allow us to extend the analysis of Shelly et al. (2007a) to parts of the Nankai Trough in Shikoku that have sparse LFE coverage, and may also allow us to extend our analysis to other regions that experience deep tremor, but where LFEs have not yet been identified. Copyright 2008 by the American Geophysical Union.

  12. Detecting an atomic clock frequency anomaly using an adaptive Kalman filter algorithm

    Science.gov (United States)

    Song, Huijie; Dong, Shaowu; Wu, Wenjun; Jiang, Meng; Wang, Weixiong

    2018-06-01

    The abnormal frequencies of an atomic clock mainly include frequency jump and frequency drift jump. Atomic clock frequency anomaly detection is a key technique in time-keeping. The Kalman filter algorithm, as a linear optimal algorithm, has been widely used in real-time detection for abnormal frequency. In order to obtain an optimal state estimation, the observation model and dynamic model of the Kalman filter algorithm should satisfy Gaussian white noise conditions. The detection performance is degraded if anomalies affect the observation model or dynamic model. The idea of the adaptive Kalman filter algorithm, applied to clock frequency anomaly detection, uses the residuals given by the prediction for building ‘an adaptive factor’ the prediction state covariance matrix is real-time corrected by the adaptive factor. The results show that the model error is reduced and the detection performance is improved. The effectiveness of the algorithm is verified by the frequency jump simulation, the frequency drift jump simulation and the measured data of the atomic clock by using the chi-square test.

  13. Novel method for detecting weak magnetic fields at low frequencies

    Science.gov (United States)

    González-Martínez, S.; Castillo-Torres, J.; Mendoza-Santos, J. C.; Zamorano-Ulloa, R.

    2005-06-01

    A low-level-intensity magnetic field detection system has been designed and developed based on the amplification-selection process of signals. This configuration is also very sensitive to magnetic field changes produced by harmonic-like electrical currents transported in finite-length wires. Experimental and theoretical results of magnetic fields detection as low as 10-9T at 120Hz are also presented with an accuracy of around 13%. The assembled equipment is designed to measure an electromotive force induced in a free-magnetic-core coil in order to recover signals which are previously selected, despite the fact that their intensities are much lower than the environment electromagnetic radiation. The prototype has a signal-to-noise ratio of 60dB. This system also presents the advantage for using it as a portable unit of measurement. The concept and prototype may be applied, for example, as a nondestructive method to analyze any corrosion formation in metallic oil pipelines which are subjected to cathodic protection.

  14. Ulysses: accurate detection of low-frequency structural variations in large insert-size sequencing libraries.

    Science.gov (United States)

    Gillet-Markowska, Alexandre; Richard, Hugues; Fischer, Gilles; Lafontaine, Ingrid

    2015-03-15

    The detection of structural variations (SVs) in short-range Paired-End (PE) libraries remains challenging because SV breakpoints can involve large dispersed repeated sequences, or carry inherent complexity, hardly resolvable with classical PE sequencing data. In contrast, large insert-size sequencing libraries (Mate-Pair libraries) provide higher physical coverage of the genome and give access to repeat-containing regions. They can thus theoretically overcome previous limitations as they are becoming routinely accessible. Nevertheless, broad insert size distributions and high rates of chimerical sequences are usually associated to this type of libraries, which makes the accurate annotation of SV challenging. Here, we present Ulysses, a tool that achieves drastically higher detection accuracy than existing tools, both on simulated and real mate-pair sequencing datasets from the 1000 Human Genome project. Ulysses achieves high specificity over the complete spectrum of variants by assessing, in a principled manner, the statistical significance of each possible variant (duplications, deletions, translocations, insertions and inversions) against an explicit model for the generation of experimental noise. This statistical model proves particularly useful for the detection of low frequency variants. SV detection performed on a large insert Mate-Pair library from a breast cancer sample revealed a high level of somatic duplications in the tumor and, to a lesser extent, in the blood sample as well. Altogether, these results show that Ulysses is a valuable tool for the characterization of somatic mosaicism in human tissues and in cancer genomes. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. Single- and multi-frequency detection of surface displacements via scanning probe microscopy.

    Science.gov (United States)

    Romanyuk, Konstantin; Luchkin, Sergey Yu; Ivanov, Maxim; Kalinin, Arseny; Kholkin, Andrei L

    2015-02-01

    Piezoresponse force microscopy (PFM) provides a novel opportunity to detect picometer-level displacements induced by an electric field applied through a conducting tip of an atomic force microscope (AFM). Recently, it was discovered that superb vertical sensitivity provided by PFM is high enough to monitor electric-field-induced ionic displacements in solids, the technique being referred to as electrochemical strain microscopy (ESM). ESM has been implemented only in multi-frequency detection modes such as dual AC resonance tracking (DART) and band excitation, where the response is recorded within a finite frequency range, typically around the first contact resonance. In this paper, we analyze and compare signal-to-noise ratios of the conventional single-frequency method with multi-frequency regimes of measuring surface displacements. Single-frequency detection ESM is demonstrated using a commercial AFM.

  16. Improved CT-detection of acute bowel ischemia using frequency selective non-linear image blending.

    Science.gov (United States)

    Schneeweiss, Sven; Esser, Michael; Thaiss, Wolfgang; Boesmueller, Hans; Ditt, Hendrik; Nikolau, Konstantin; Horger, Marius

    2017-07-01

    Computed tomography (CT) as a fast and reliable diagnostic technique is the imaging modality of choice for acute bowel ischemia. However, diagnostic is often difficult mainly due to low attenuation differences between ischemic and perfused segments. To compare the diagnostic efficacy of a new post-processing tool based on frequency selective non-linear blending with that of conventional linear contrast-enhanced CT (CECT) image blending for the detection of bowel ischemia. Twenty-seven consecutive patients (19 women; mean age = 73.7 years, age range = 50-94 years) with acute bowel ischemia were scanned using multidetector CT (120 kV; 100-200 mAs). Pre-contrast and portal venous scans (65-70 s delay) were acquired. All patients underwent surgery for acute bowel ischemia and intraoperative diagnosis as well as histologic evaluation of explanted bowel segments was considered "gold standard." First, two radiologists read the conventional CECT images in which linear blending was adapted for optimal contrast, and second (three weeks later) the frequency selective non-linear blending (F-NLB) image. Attenuation values were compared, both in the involved and non-involved bowel segments creating ratios between unenhanced and CECT. The mean attenuation difference between ischemic and non-ischemic wall in the portal venous scan was 69.54 HU (reader 2 = 69.01 HU) higher for F-NLB compared with conventional CECT. Also, the attenuation ratio between contrast-enhanced and pre-contrast CT data for the non-ischemic walls showed significantly higher values for the F-NLB image (CECT: reader 1 = 2.11 (reader 2 = 3.36), F-NLB: reader 1 = 4.46 (reader 2 = 4.98)]. Sensitivity in detecting ischemic areas increased significantly for both readers using F-NLB (CECT: reader 1/2 = 53%/65% versus F-NLB: reader 1/2 = 62%/75%). Frequency selective non-linear blending improves detection of bowel ischemia compared with conventional CECT by increasing

  17. Bilinear Time-frequency Analysis for Lamb Wave Signal Detected by Electromagnetic Acoustic Transducer

    Science.gov (United States)

    Sun, Wenxiu; Liu, Guoqiang; Xia, Hui; Xia, Zhengwu

    2018-03-01

    Accurate acquisition of the detection signal travel time plays a very important role in cross-hole tomography. The experimental platform of aluminum plate under the perpendicular magnetic field is established and the bilinear time-frequency analysis methods, Wigner-Ville Distribution (WVD) and the pseudo-Wigner-Ville distribution (PWVD), are applied to analyse the Lamb wave signals detected by electromagnetic acoustic transducer (EMAT). By extracting the same frequency component of the time-frequency spectrum as the excitation frequency, the travel time information can be obtained. In comparison with traditional linear time-frequency analysis method such as short-time Fourier transform (STFT), the bilinear time-frequency analysis method PWVD is more appropriate in extracting travel time and recognizing patterns of Lamb wave.

  18. Time-Frequency Analysis of Terahertz Radar Signals for Rapid Heart and Breath Rate Detection

    National Research Council Canada - National Science Library

    Massar, Melody L

    2008-01-01

    We develop new time-frequency analytic techniques which facilitate the detection of a person's heart and breath rates from the Doppler shift the movement of their body induces in a terahertz radar signal...

  19. Head Injury and Intracranial Pressure Monitor Using Ultrasonic and Low-Frequency Acoustic (ULFA) Detection

    National Research Council Canada - National Science Library

    Vo-Dinh, Tuan

    2001-01-01

    The main objective of this research project is the development of a non-invasive method and instrument for head injury detection and monitoring using a new approach based on ultrasonic and low-frequency acoustic (ULFA...

  20. Head Injury and Intracranial Pressure Monitor Using Ultrasonic and Low-Frequency (ULFA) Detection

    National Research Council Canada - National Science Library

    Vo-Dinh, Tuan

    2000-01-01

    The main objective of this research project is the development of a non-invasive method and instrument for head injury detection and monitoring using a new approach based on ultrasonic and low-frequency acoustic (ULFA...

  1. Frequency hopping signal detection based on wavelet decomposition and Hilbert-Huang transform

    Science.gov (United States)

    Zheng, Yang; Chen, Xihao; Zhu, Rui

    2017-07-01

    Frequency hopping (FH) signal is widely adopted by military communications as a kind of low probability interception signal. Therefore, it is very important to research the FH signal detection algorithm. The existing detection algorithm of FH signals based on the time-frequency analysis cannot satisfy the time and frequency resolution requirement at the same time due to the influence of window function. In order to solve this problem, an algorithm based on wavelet decomposition and Hilbert-Huang transform (HHT) was proposed. The proposed algorithm removes the noise of the received signals by wavelet decomposition and detects the FH signals by Hilbert-Huang transform. Simulation results show the proposed algorithm takes into account both the time resolution and the frequency resolution. Correspondingly, the accuracy of FH signals detection can be improved.

  2. Gear-box fault detection using time-frequency based methods

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2015-01-01

    Gear-box fault monitoring and detection is important for optimization of power generation and availability of wind turbines. The current industrial approach is to use condition monitoring systems, which runs in parallel with the wind turbine control system, using expensive additional sensors...... in the gear-box resonance frequency can be detected. Two different time–frequency based approaches are presented in this paper. One is a filter based approach and the other is based on a Karhunen–Loeve basis. Both of them detect the gear-box fault with an acceptable detection delay of maximum 100s, which...... is neglectable compared with the fault developing time....

  3. Development of a heterodyne laser interferometer for very small high frequency displacements detection

    International Nuclear Information System (INIS)

    Baarmann, P.

    1992-10-01

    A heterodyne laser interferometer with detection electronics has been developed for measuring very small amplitude high frequency vibrations. A laser beam from HeNe-laser is focused and reflected in the vibrating surface and the generated phase shifts are after interference with a reference beam detected with a photo detector and evaluated in a demodulation system. The set-up is a prototype and techniques to improve the accuracy and sensitivity of the system are presented. The present system can detect vibration amplitude from around 1 Angstrom and is linear up to 250 Angstrom (±4%). Frequencies from a few tens of kHz up to tens of MHz are covered. The low frequency region can be greatly improved. The minimum detectable displacement may be improved by narrowing the bandwidth of the detection system to the region of interest

  4. Signal Detection Theory-Based Information Processing for the Detection of Breast Cancer at Microwave Frequencies

    National Research Council Canada - National Science Library

    Nolte, Loren

    2002-01-01

    The hypothesis is that one can use signal detection theory to improve the performance in detecting tumors in the breast by using this theory to develop task-oriented information processing techniques...

  5. Higher frequency of brain abnormalities in neuromyelitis optica spectrum disorder patients without primary Sjögren's syndrome.

    Science.gov (United States)

    Gu, Li-Na; Zhang, Min; Zhu, Hui; Liu, Jing-Yao

    2016-10-01

    Neuromyelitis optica spectrum disorder often co-exists with primary Sjögren's syndrome. We compared the clinical features of 16 neuromyelitis optica spectrum disorder patients with ( n = 6) or without primary Sjögren's syndrome ( n = 10). All patients underwent extensive clinical, laboratory, and MRI evaluations. There were no statistical differences in demographics or first neurological involvement at onset between neuromyelitis optica spectrum disorder patients with and without primary Sjögren's syndrome. The laboratory findings of cerebrospinal fluid oligoclonal banding, serum C-reactive protein, antinuclear autoantibody, anti-Sjögren's-syndrome-related antigen A antibodies, anti-Sjögren's-syndrome-related antigen B antibodies, and anti-Sm antibodies were significantly higher in patients with primary Sjögren's syndrome than those without. Anti-aquaporin 4 antibodies were detectable in 67% (4/6) of patients with primary Sjögren's syndrome and in 60% (6/10) of patients without primary Sjögren's syndrome. More brain abnormalities were observed in patients without primary Sjögren's syndrome than in those with primary Sjögren's syndrome. Segments lesions (> 3 centrum) were noted in 50% (5/10) of patients without primary Sjögren's syndrome and in 67% (4/6) of patients with primary Sjögren's syndrome. These findings indicate that the clinical characteristics of neuromyelitis optica spectrum disorder patients with and without primary Sjögren's syndrome are similar. However, neuromyelitis optica spectrum disorder patients without primary Sjögren's syndrome have a high frequency of brain abnormalities.

  6. A higher meal frequency may be associated with diminished weight loss after bariatric surgery

    OpenAIRE

    RIBEIRO, Angela Gadelha; COSTA, Maria José de Carvalho; FAINTUCH, Joel; DIAS, Maria Carolina Gonçalves

    2009-01-01

    OBJECTIVE: This study aimed to investigate the relationship between meal frequency, the occurrence of vomiting and weight loss among patients submitted to Roux-en-Y gastric bypass up to 9 months after surgery. METHODS: Female patients (n = 80) were followed at 3-month intervals for 9 months. Weight, BMI, 24-hour dietary recall, drug consumption and vomiting episodes were recorded and compared with nutritional outcome. RESULTS: The BMI values at 3, 6 and 9 months were 45.1 ± 9.7, 39.9 ± 7.6 an...

  7. Human-robot collision detection under modeling uncertainty using frequency boundary of manipulator dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Byung Jin; Koo, Ja Choon; Choi, Hyouk Ryeol; Moon, Hyung Pil [Sungkyunkwan University, Suwon (Korea, Republic of)

    2014-11-15

    This paper presents the development and experimental evaluation of a collision detection method for robotic manipulators sharing a workspace with humans. Fast and robust collision detection is important for guaranteeing safety and preventing false alarms. The main cause of a false alarm is modeling error. We use the characteristic of the maximum frequency boundary of the manipulator's dynamic model. The tendency of the frequency boundary's location in the frequency domain is applied to the collision detection algorithm using a band pass filter (band designed disturbance observer, BdDOB) with changing frequency windows. Thanks to the band pass filter, which considers the frequency boundary of the dynamic model, our collision detection algorithm can extract the collision caused by the disturbance from the mixed estimation signal. As a result, the collision was successfully detected under the usage conditions of faulty sensors and uncertain model data. The experimental result of a collision between a 7-DOF serial manipulator and a human body is reported.

  8. Frequency-domain interferometer simulation with higher-order spatial modes

    International Nuclear Information System (INIS)

    Freise, A; Heinzel, G; Lueck, H; Schilling, R; Willke, B; Danzmann, K

    2004-01-01

    FINESSE is a software simulation allowing one to compute the optical properties of laser interferometers used by interferometric gravitational-wave detectors today. This fast and versatile tool has already proven to be useful in the design and commissioning of gravitational-wave detectors. The basic algorithm of FINESSE numerically computes the light amplitudes inside an interferometer using Hermite-Gauss modes in the frequency domain. In addition, FINESSE provides a number of commands for easily generating and plotting the most common signals including power enhancement, error and control signals, transfer functions and shot-noise-limited sensitivities. Among the various simulation tools available to the gravitational wave community today, FINESSE provides an advanced and versatile optical simulation based on a general analysis of user-defined optical setups and is quick to install and easy to use

  9. The Influence of Higher Protein Intake and Greater Eating Frequency on Appetite Control in Overweight and Obese Men

    Science.gov (United States)

    Leidy, Heather J.; Armstrong, Cheryl L.H.; Tang, Minghua; Mattes, Richard D.; Campbell, Wayne W.

    2014-01-01

    The purpose of this study was to determine the effects of dietary protein intake and eating frequency on perceived appetite, satiety, and hormonal responses in overweight/obese men. Thirteen men (age 51 ± 4 years; BMI 31.3 ± 0.8 kg/m2) consumed eucaloric diets containing normal protein (79 ± 2 g protein/day; 14% of energy intake as protein) or higher protein (138 ± 3 g protein/day; 25% of energy intake as protein) equally divided among three eating occasions (3-EO; every 4 h) or six eating occasions (6-EO; every 2 h) on four separate days in randomized order. Hunger, fullness, plasma glucose, and hormonal responses were assessed throughout 11 h. No protein × eating frequency interactions were observed for any of the outcomes. Independent of eating frequency, higher protein led to greater daily fullness (P < 0.05) and peptide YY (PYY) concentrations (P < 0.05). In contrast, higher protein led to greater daily ghrelin concentrations (P < 0.05) vs. normal protein. Protein quantity did not influence daily hunger, glucose, or insulin concentrations. Independent of dietary protein, 6-EO led to lower daily fullness (P < 0.05) and PYY concentrations (P < 0.05). The 6-EO also led to lower glucose (P < 0.05) and insulin concentrations (P < 0.05) vs. 3-EO. Although the hunger-related perceived sensations and hormonal responses were conflicting, the fullness-related responses were consistently greater with higher protein intake but lower with increased eating frequency. Collectively, these data suggest that higher protein intake promotes satiety and challenge the concept that increasing the number of eating occasions enhances satiety in overweight and obese men. PMID:20339363

  10. Proposed Sandia frequency shift for anti-islanding detection method based on artificial immune system

    Directory of Open Access Journals (Sweden)

    A.Y. Hatata

    2018-03-01

    Full Text Available Sandia frequency shift (SFS is one of the active anti-islanding detection methods that depend on frequency drift to detect an islanding condition for inverter-based distributed generation. The non-detection zone (NDZ of the SFS method depends to a great extent on its parameters. Improper adjusting of these parameters may result in failure of the method. This paper presents a proposed artificial immune system (AIS-based technique to obtain optimal parameters of SFS anti-islanding detection method. The immune system is highly distributed, highly adaptive, and self-organizing in nature, maintains a memory of past encounters, and has the ability to continually learn about new encounters. The proposed method generates less total harmonic distortion (THD than the conventional SFS, which results in faster island detection and better non-detection zone. The performance of the proposed method is derived analytically and simulated using Matlab/Simulink. Two case studies are used to verify the proposed method. The first case includes a photovoltaic (PV connected to grid and the second includes a wind turbine connected to grid. The deduced optimized parameter setting helps to achieve the “non-islanding inverter” as well as least potential adverse impact on power quality. Keywords: Anti-islanding detection, Sandia frequency shift (SFS, Non-detection zone (NDZ, Total harmonic distortion (THD, Artificial immune system (AIS, Clonal selection algorithm

  11. Low frequency geomagnetic field fluctuations at low latitude during the passage of a higher pressure solar wind region

    Directory of Open Access Journals (Sweden)

    U. Villante

    1997-06-01

    Full Text Available The passage of a higher pressure solar wind region at the Earth's orbit marked the onset of low latitude (L=1.6 fluctuations in the frequency range (0.8–5.5 mHz for both the horizontal geomagnetic field components. Spectral peaks mostly occur at the same frequencies as the spectral enhancements which appeared in the long term analysis of experimental measurements from the same station and were tentatively interpreted in terms of ground signatures of global magnetospheric modes. A comparison with simultaneous observations discussed by previous investigations allows us to conclude that the same set of frequencies is enhanced in a wide portion of the Earth's magnetosphere.

  12. A higher meal frequency may be associated with diminished weight loss after bariatric surgery.

    Science.gov (United States)

    Ribeiro, Angela Gadelha; Costa, Maria José de Carvalho; Faintuch, Joel; Dias, Maria Carolina Gonçalves

    2009-01-01

    This study aimed to investigate the relationship between meal frequency, the occurrence of vomiting and weight loss among patients submitted to Roux-en-Y gastric bypass up to 9 months after surgery. Female patients (n = 80) were followed at 3-month intervals for 9 months. Weight, BMI, 24-hour dietary recall, drug consumption and vomiting episodes were recorded and compared with nutritional outcome. The BMI values at 3, 6 and 9 months were 45.1 +/- 9.7, 39.9 +/- 7.6 and 35.4 +/- 8.2 kg/m(2), respectively. The corresponding choleric intakes were 535.6 +/- 295.7, 677.1 +/- 314.7 and 828.6 +/- 398.2 kcal/day, and the numbers of daily meals were 5.0 +/- 2.5, 4.7 +/- 1.8 and 4.9 +/- 1.0, respectively. The peak of vomiting episodes occurred within 6 months; however, patients tolerated this complication despite its high prevalence. A significant negative correlation between weight loss and diet fractioning, but not vomiting, was observed throughout the entire postoperative period (P = 0.001). 1) Frequent small meals were associated with a reduction in weight loss after gastric bypass and a decrease in vomiting episodes at 6 months, and 2) vomiting did not interfere with nutritional outcome. Unless required because of vomiting or other reasons, multiple small meals may not be advantageous after such intervention.

  13. Francisella tularensis detection using magnetic labels and a magnetic biosensor based on frequency mixing

    International Nuclear Information System (INIS)

    Meyer, Martin H.F.; Krause, Hans-Joachim; Hartmann, Markus; Miethe, Peter; Oster, Juergen; Keusgen, Michael

    2007-01-01

    A biosensor that uses resonant coils with a special frequency-mixing technique and magnetic beads as detectable labels has been established for the detection of Francisella tularensis, the causative agent for tularemia. The detection principle is based on a sandwich immunoassay using an anti-Ft antibody for immunofiltration immobilized to ABICAP[reg] polyethylene filters, and biotinylated with streptavidin-coated magnetic beads as labels. The linear detection range of this biosensor was found to be 10 4 -10 6 cfu F. tularensis lipopolysaccharide (LPS) per ml. Tested sample matrices were physiological PBS buffer and rabbit serum

  14. Francisella tularensis detection using magnetic labels and a magnetic biosensor based on frequency mixing

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Martin H.F. [Institute for Pharmaceutical Chemistry, Philipps-Universitaet Marburg (Germany); Krause, Hans-Joachim [Institute of Bio-and Nanosystems (IBN-2), Research Center Juelich (Germany); Hartmann, Markus [Institute for Pharmaceutical Chemistry, Philipps-Universitaet Marburg (Germany); Miethe, Peter [SENOVA GmbH, Jena (Germany); Oster, Juergen [chemagen GmbH, Baesweiler (Germany); Keusgen, Michael [Institute for Pharmaceutical Chemistry, Philipps-Universitaet Marburg (Germany)]. E-mail: Keusgen@staff.uni-marburg.de

    2007-04-15

    A biosensor that uses resonant coils with a special frequency-mixing technique and magnetic beads as detectable labels has been established for the detection of Francisella tularensis, the causative agent for tularemia. The detection principle is based on a sandwich immunoassay using an anti-Ft antibody for immunofiltration immobilized to ABICAP[reg] polyethylene filters, and biotinylated with streptavidin-coated magnetic beads as labels. The linear detection range of this biosensor was found to be 10{sup 4}-10{sup 6} cfu F. tularensis lipopolysaccharide (LPS) per ml. Tested sample matrices were physiological PBS buffer and rabbit serum.

  15. Sinusoidal oscillators with lower gain requirements at higher frequencies based on an explicit tanh(x) nonlinearity

    KAUST Repository

    Elwakil, Ahmed S.

    2009-04-28

    Two novel sinusoidal oscillator structures with an explicit tanh(x) nonlinearity are proposed. The oscillators have the attractive feature: the higher the operating frequency, the lower the necessary gain required to start oscillations. A nonlinear model for the two oscillators is derived and verified numerically. Spice simulations using AMS BiCMOS 0.35 μ model parameters and experimental results are shown. Copyright © 2009 John Wiley & Sons, Ltd.

  16. A novel reduced-complexity group detection structure in MIMO frequency selective fading channels

    KAUST Repository

    Qaraqe, Khalid A.; Ahimian, Nariman R.; Alouini, Mohamed-Slim

    2010-01-01

    In this paper a novel reduced complexity detection method named modified symbol flipping method is introduced and its advantages on reducing the burden of the calculations at the receiver compared to the optimum maximum likelihood detection method on multiple input- multiple output frequency selective fading channels are explained. The initial concept of the symbol flipping method is derived from a preliminary detection scheme named bit flipping which was introduced in [1]. The detection structure employed in this paper is ing, detection, and cancellation. On the detection stage, the proposed method is employed and the results are compared to the group maximum likelihood detection scheme proposed in [2]. Simulation results show that a 6 dB performance gain can be achieved at the expense of a slight increase in complexity in comparison with the conventional symbol flipping scheme. © 2010 Crown.

  17. A novel reduced-complexity group detection structure in MIMO frequency selective fading channels

    KAUST Repository

    Qaraqe, Khalid A.

    2010-09-01

    In this paper a novel reduced complexity detection method named modified symbol flipping method is introduced and its advantages on reducing the burden of the calculations at the receiver compared to the optimum maximum likelihood detection method on multiple input- multiple output frequency selective fading channels are explained. The initial concept of the symbol flipping method is derived from a preliminary detection scheme named bit flipping which was introduced in [1]. The detection structure employed in this paper is ing, detection, and cancellation. On the detection stage, the proposed method is employed and the results are compared to the group maximum likelihood detection scheme proposed in [2]. Simulation results show that a 6 dB performance gain can be achieved at the expense of a slight increase in complexity in comparison with the conventional symbol flipping scheme. © 2010 Crown.

  18. Multi-beam synchronous measurement based on PSD phase detection using frequency-domain multiplexing

    Science.gov (United States)

    Duan, Ying; Qin, Lan; Xue, Lian; Xi, Feng; Mao, Jiubing

    2013-10-01

    According to the principle of centroid measurement, position-sensitive detectors (PSD) are commonly used for micro displacement detection. However, single-beam detection method cannot satisfy such tasks as multi-dimension position measurement, three dimension vision reconstruction, and robot precision positioning, which require synchronous measurement of multiple light beams. Consequently, we designed PSD phase detection method using frequency-domain multiplexing for synchronous detection of multiple modulated light beams. Compared to previous PSD amplitude detection method, the phase detection method using FDM has advantages of simplified measuring system, low cost, high capability of resistance to light interference as well as improved resolution. The feasibility of multi-beam synchronous measurement based on PSD phase detection using FDM was validated by multi-beam measuring experiments. The maximum non-linearity error of the multi-beam synchronous measurement is 6.62%.

  19. Higher frequency of isolated PMS2 loss in colorectal tumors in Colombian population: preliminary results

    Directory of Open Access Journals (Sweden)

    Shamekh R

    2016-08-01

    Full Text Available Rania Shamekh,1 Mauro Cives,2 Jaime Mejia,3 Domenico Coppola,4 1Department of Pathology, University of South Florida, 2Department of Gastrointestinal Oncology, Moffitt Cancer Center, Tampa, FL, USA; 3Department of Pathology, Institutode Patologia Mejia Jimenez, Cali, Colombia; 4Department of Anatomic Pathology, Moffitt Cancer Center, Tampa, FL, USA Abstract: Colorectal cancer (CRC is the third most common cancer and the fourth most common cause of death worldwide. It accounts for >9% of all cancers. One of the pathogenic factors of CRC is germline mutation, leading to alteration and inactivation in the mismatch repair (MMR genes. The aim of the study is to compare the frequency of alterations in MMR protein expression in Caucasian CRC patients with Colombian CRC patients. A total of 45 Colombians and 48 Caucasians with CRC were studied. The microsatellite instability status of tumors was determined in primary CRC by immunohistochemistry using the automated Ventana Ultra. The combined loss of MLH1 and PMS2 was the most common alteration in both Colombian (11%, five out of 45 and Caucasian (12%, six out of 48 CRC patients. Interestingly, the loss of PMS2 expression in the presence of intact MLH1 was the second most common alteration in Colombians (8%, four out of 45, which was never seen in the Caucasian cohort (P=0.05. The loss of MLH1 alone and the combined loss of MSH6 and PMS2 expression were only observed in one out of 45 (2% Colombians but not in Caucasians. The combined loss of MSH2 and MSH6 was not observed in any of the patients studied. The preliminary findings support a significant difference in alterations of MMR protein expression in Colombian CRC patients compared with Caucasian CRC patients. These findings are novel and warrant further studies in larger cohorts. Keywords: colon cancer, MSI, MMR, immunohistochemistry

  20. A higher meal frequency may be associated with diminished weight loss after bariatric surgery

    Directory of Open Access Journals (Sweden)

    Angela Gadelha Ribeiro

    2009-11-01

    Full Text Available OBJECTIVE: This study aimed to investigate the relationship between meal frequency, the occurrence of vomiting and weight loss among patients submitted to Roux-en-Y gastric bypass up to 9 months after surgery. METHODS: Female patients (n = 80 were followed at 3-month intervals for 9 months. Weight, BMI, 24-hour dietary recall, drug consumption and vomiting episodes were recorded and compared with nutritional outcome. RESULTS: The BMI values at 3, 6 and 9 months were 45.1 ± 9.7, 39.9 ± 7.6 and 35.4 ± 8.2 kg/m², respectively. The corresponding choleric intakes were 535.6 ± 295.7, 677.1 ± 314.7 and 828.6 ± 398.2 kcal/day, and the numbers of daily meals were 5.0 ± 2.5, 4.7 ± 1.8 and 4.9 ± 1.0, respectively. The peak of vomiting episodes occurred within 6 months; however, patients tolerated this complication despite its high prevalence. A significant negative correlation between weight loss and diet fractioning, but not vomiting, was observed throughout the entire postoperative period (P = 0.001. CONCLUSIONS: 1 Frequent small meals were associated with a reduction in weight loss after gastric bypass and a decrease in vomiting episodes at 6 months, and 2 vomiting did not interfere with nutritional outcome. Unless required because of vomiting or other reasons, multiple small meals may not be advantageous after such intervention.

  1. [Detection of endotoxins of Gram-negative bacteria on the basis of electromagnetic radiation frequency spectrum].

    Science.gov (United States)

    Likhoded, V G; Kuleshova, N V; Sergieva, N V; Konev, Iu V; Trubnikova, I A; Sudzhian, E V

    2007-01-01

    Method of Gram-negative bacteria endotoxins detection on the basis of their own spectrum of electromagnetic radiation frequency was developed. Frequency spectrum typical for chemotype Re glycolipid, which is a part of lypopolysaccharides in the majority of Gram-negative bacteria, was used. Two devices--"Mini- Expert-DT" (manufactured by IMEDIS, Moscow) and "Bicom" (manufactured by Regumed, Germany)--were used as generators of electromagnetic radiation. Detection of endotoxin using these devices was performed by electropuncture vegetative resonance test. Immunoenzyme reaction with antibodies to chemotype Re glycolipid was used during analysis of preparations for assessment of resonance-frequency method specificity. The study showed that resonance-frequency method can detect lypopolysaccharides of different enterobacteria in quantities up to 0.1 pg as well as bacteria which contain lypopolysaccharides. At the same time, this method does not detect such bacteria as Staphylococcus aureus, Bifidobacterium spp., Lactobacillus spp., and Candida albicans. The method does not require preliminary processing of blood samples and can be used for diagnostics of endotoxinemia, and detection of endotoxins in blood samples or injection solutions.

  2. Detection of horizontal transfer of individual genes by anomalous oligomer frequencies

    Directory of Open Access Journals (Sweden)

    Elhai Jeff

    2012-06-01

    Full Text Available Abstract Background Understanding the history of life requires that we understand the transfer of genetic material across phylogenetic boundaries. Detecting genes that were acquired by means other than vertical descent is a basic step in that process. Detection by discordant phylogenies is computationally expensive and not always definitive. Many have used easily computed compositional features as an alternative procedure. However, different compositional methods produce different predictions, and the effectiveness of any method is not well established. Results The ability of octamer frequency comparisons to detect genes artificially seeded in cyanobacterial genomes was markedly increased by using as a training set those genes that are highly conserved over all bacteria. Using a subset of octamer frequencies in such tests also increased effectiveness, but this depended on the specific target genome and the source of the contaminating genes. The presence of high frequency octamers and the GC content of the contaminating genes were important considerations. A method comprising best practices from these tests was devised, the Core Gene Similarity (CGS method, and it performed better than simple octamer frequency analysis, codon bias, or GC contrasts in detecting seeded genes or naturally occurring transposons. From a comparison of predictions with phylogenetic trees, it appears that the effectiveness of the method is confined to horizontal transfer events that have occurred recently in evolutionary time. Conclusions The CGS method may be an improvement over existing surrogate methods to detect genes of foreign origin.

  3. Prospects for detecting decreasing exoplanet frequency with main-sequence age using PLATO

    Science.gov (United States)

    Veras, D.; Brown, D. J. A.; Mustill, A. J.; Pollacco, D.

    2017-09-01

    The space mission PLATO will usher in a new era of exoplanetary science by expanding our current inventory of transiting systems and constraining host star ages, which are currently highly uncertain. This capability might allow PLATO to detect changes in planetary system architecture with time, particularly because planetary scattering due to Lagrange instability may be triggered long after the system was formed. Here, we utilize previously published instability time-scale prescriptions to determine PLATO's capability to detect a trend of decreasing planet frequency with age for systems with equal- mass planets. For two-planet systems, our results demonstrate that PLATO may detect a trend for planet masses which are at least as massive as super-Earths. For systems with three or more planets, we link their initial compactness to potentially detectable frequency trends in order to aid future investigations when these populations will be better characterized.

  4. Frequency-scanning MALDI linear ion trap mass spectrometer for large biomolecular ion detection.

    Science.gov (United States)

    Lu, I-Chung; Lin, Jung Lee; Lai, Szu-Hsueh; Chen, Chung-Hsuan

    2011-11-01

    This study presents the first report on the development of a matrix-assisted laser desorption ionization (MALDI) linear ion trap mass spectrometer for large biomolecular ion detection by frequency scan. We designed, installed, and tested this radio frequency (RF) scan linear ion trap mass spectrometer and its associated electronics to dramatically extend the mass region to be detected. The RF circuit can be adjusted from 300 to 10 kHz with a set of operation amplifiers. To trap the ions produced by MALDI, a high pressure of helium buffer gas was employed to quench extra kinetic energy of the heavy ions produced by MALDI. The successful detection of the singly charged secretory immunoglobulin A ions indicates that the detectable mass-to-charge ratio (m/z) of this system can reach ~385 000 or beyond.

  5. Detection of admittivity anomaly on high-contrast heterogeneous backgrounds using frequency difference EIT.

    Science.gov (United States)

    Jang, J; Seo, J K

    2015-06-01

    This paper describes a multiple background subtraction method in frequency difference electrical impedance tomography (fdEIT) to detect an admittivity anomaly from a high-contrast background conductivity distribution. The proposed method expands the use of the conventional weighted frequency difference EIT method, which has been used limitedly to detect admittivity anomalies in a roughly homogeneous background. The proposed method can be viewed as multiple weighted difference imaging in fdEIT. Although the spatial resolutions of the output images by fdEIT are very low due to the inherent ill-posedness, numerical simulations and phantom experiments of the proposed method demonstrate its feasibility to detect anomalies. It has potential application in stroke detection in a head model, which is highly heterogeneous due to the skull.

  6. Feasibility Studies on the Use of Higher Frequency Bands and Beamforming Selection Scheme for High Speed Train Communication

    Directory of Open Access Journals (Sweden)

    Ayotunde O. Laiyemo

    2017-01-01

    Full Text Available With increasing popularity of high speed trains and traffic forecast for future cellular networks, the need to provide improved data rates using higher frequency bands (HFBs for train passengers is becoming crucial. In this paper, we modify the OFDM frame structure for HST, taking into account the increasing sensitivity to speed at HFBs. A lower bound on the SNR/SINR for a given rate for reliable communication was derived considering the physical layer parameters from the OFDM frame. We also analyze different pathloss models in the context of examining the required gain needed to achieve the same performance as with microwave bands. Finally, we present a time-based analogue beamforming selection approach for HST. We observed that, irrespective of the pathloss models used, the required gains are within the same range. For the same SNR/SINR at different frequency bands, the achievable data rate varies with respect to the frequency bands. Our results show the potential of the use of HFBs. However, due to the increased sensitivity of some channel parameters, a maximum frequency band of 38 GHz is suggested. Evaluation of our proposed beamforming scheme indicates a close performance to the optimal SVD scheme with a marginal rate gap of less than 2 b/s/Hz.

  7. Complex Signal Kurtosis and Independent Component Analysis for Wideband Radio Frequency Interference Detection

    Science.gov (United States)

    Schoenwald, Adam; Mohammed, Priscilla; Bradley, Damon; Piepmeier, Jeffrey; Wong, Englin; Gholian, Armen

    2016-01-01

    Radio-frequency interference (RFI) has negatively implicated scientific measurements across a wide variation passive remote sensing satellites. This has been observed in the L-band radiometers SMOS, Aquarius and more recently, SMAP [1, 2]. RFI has also been observed at higher frequencies such as K band [3]. Improvements in technology have allowed wider bandwidth digital back ends for passive microwave radiometry. A complex signal kurtosis radio frequency interference detector was developed to help identify corrupted measurements [4]. This work explores the use of ICA (Independent Component Analysis) as a blind source separation technique to pre-process radiometric signals for use with the previously developed real and complex signal kurtosis detectors.

  8. Welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems using fundamental- and higher-resonance frequencies.

    Science.gov (United States)

    Tsujino, Jiromaru; Hongoh, Misugi; Yoshikuni, Masafumi; Hashii, Hidekazu; Ueoka, Tetsugi

    2004-04-01

    The welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems that are driven at only the fundamental-resonance frequency vibration were compared, and also those of the welding systems that were driven at the fundamental and several higher resonance frequencies simultaneously were studied. At high frequency, welding characteristics can be improved due to the larger vibration loss of plastic materials. For welding of rather thin or small specimens, as the fundamental frequency of these welding systems is higher and the numbers of driven higher frequencies are driven simultaneously, larger welded area and weld strength were obtained.

  9. Damage Detection Based on Cross-Term Extraction from Bilinear Time-Frequency Distributions

    Directory of Open Access Journals (Sweden)

    Ma Yuchao

    2014-01-01

    Full Text Available Abundant damage information is implicated in the bilinear time-frequency distribution of structural dynamic signals, which could provide effective support for structural damage identification. Signal time-frequency analysis methods are reviewed, and the characters of linear time-frequency distribution and bilinear time-frequency distribution typically represented by the Wigner-Ville distribution are compared. The existence of the cross-term and its application in structural damage detection are demonstrated. A method of extracting the dominant term is proposed, which combines the short-time Fourier spectrum and Wigner-Ville distribution; then two-dimensional time-frequency transformation matrix is constructed and the complete cross-term is extracted finally. The distribution character of which could be applied to the structural damage identification. Through theoretical analysis, model experiment and numerical simulation of the girder structure, the change rate of cross-term amplitude is validated to identify the damage location and degree. The effectiveness of the cross-term of bilinear time-frequency distribution for damage detection is confirmed and the analytical method of damage identification used in structural engineering is available.

  10. Change detection in quad and dual pol, single- and bi-frequency SAR data

    DEFF Research Database (Denmark)

    Nielsen, Allan Aasbjerg; Conradsen, Knut; Skriver, Henning

    2015-01-01

    -value are given. In a case study airborne EMISAR C- and L-band SAR images covering agricultural fields and wooded areas near Foulum, Denmark, are used in single- and bi-frequency, bi-temporal change detection with full and dual polarimetry data. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation...

  11. CoSMOS: Performance of Kurtosis Algorithm for Radio Frequency Interference Detection and Mitigation

    DEFF Research Database (Denmark)

    Misra, Sidharth; Kristensen, Steen Savstrup; Skou, Niels

    2007-01-01

    The performance of a previously developed algorithm for Radio Frequency Interference (RFI) detection and mitigation is experimentally evaluated. Results obtained from CoSMOS, an airborne campaign using a fully polarimetric L-band radiometer are analyzed for this purpose. Data is collected using two...

  12. Cantilever-detected high-frequency ESR measurement using a backward travelling wave oscillator

    International Nuclear Information System (INIS)

    Tokuda, Y; Hirano, S; Ohmichi, E; Ohta, H

    2012-01-01

    Our cantilever-detected electron spin resonance (ESR) technique is motivated for terahertz ESR spectroscopy of a tiny single crystal at low temperature. In this technique, ESR signal is detected as deflection of a sample-mounted cantilever, which is sensitively detected by built-in piezoresistors. So far, ESR detection at 315 GHz was succeeded using Gunn oscillator. In this study, we combine our ESR technique with a backward traveling wave oscillator (BWO), which can cover a wide frequency range 120-1200 GHz, to achieve better spectral resolution. Experiments were carried out at 4.2 K for a single crystal of Co Tutton salt with a newly constructed optical system. We successfully observed two ESR absorption lines in BWO frequencies up to 370 GHz. From multi-frequency measurements, the observed ESR lines shifted linearly with BWO frequency, being consistent with paramagnetic resonance. The estimated g values are g 1 = 3.00 and g 2 = 3.21. The spin sensitivity was estimated to ∼10 12 spins/gauss at 370 GHz.

  13. Prospects of Frequency-Time Correlation Analysis for Detecting Pipeline Leaks by Acoustic Emission Method

    International Nuclear Information System (INIS)

    Faerman, V A; Cheremnov, A G; Avramchuk, V V; Luneva, E E

    2014-01-01

    In the current work the relevance of nondestructive test method development applied for pipeline leak detection is considered. It was shown that acoustic emission testing is currently one of the most widely spread leak detection methods. The main disadvantage of this method is that it cannot be applied in monitoring long pipeline sections, which in its turn complicates and slows down the inspection of the line pipe sections of main pipelines. The prospects of developing alternative techniques and methods based on the use of the spectral analysis of signals were considered and their possible application in leak detection on the basis of the correlation method was outlined. As an alternative, the time-frequency correlation function calculation is proposed. This function represents the correlation between the spectral components of the analyzed signals. In this work, the technique of time-frequency correlation function calculation is described. The experimental data that demonstrate obvious advantage of the time-frequency correlation function compared to the simple correlation function are presented. The application of the time-frequency correlation function is more effective in suppressing the noise components in the frequency range of the useful signal, which makes maximum of the function more pronounced. The main drawback of application of the time- frequency correlation function analysis in solving leak detection problems is a great number of calculations that may result in a further increase in pipeline time inspection. However, this drawback can be partially reduced by the development and implementation of efficient algorithms (including parallel) of computing the fast Fourier transform using computer central processing unit and graphic processing unit

  14. Resolution improvement of low frequency AC magnetic field detection for modulated MR sensors.

    Science.gov (United States)

    Hu, Jinghua; Pan, Mengchun; Hu, Jiafei; Li, Sizhong; Chen, Dixiang; Tian, Wugang; Sun, Kun; Du, Qingfa; Wang, Yuan; Pan, Long; Zhou, Weihong; Zhang, Qi; Li, Peisen; Peng, Junping; Qiu, Weicheng; Zhou, Jikun

    2017-09-01

    Magnetic modulation methods especially Micro-Electro-Mechanical System (MEMS) modulation can improve the sensitivity of magnetoresistive (MR) sensors dramatically, and pT level detection of Direct Current (DC) magnetic field can be realized. While in a Low Frequency Alternate Current (LFAC) magnetic field measurement situation, frequency measurement is limited by a serious spectrum aliasing problem caused by the remanence in sensors and geomagnetic field, leading to target information loss because frequency indicates the magnetic target characteristics. In this paper, a compensation field produced with integrated coils is applied to the MR sensor to remove DC magnetic field distortion, and a LFAC magnetic field frequency estimation algorithm is proposed based on a search of the database, which is derived from the numerical model revealing the relationship of the LFAC frequency and determination factor [defined by the ratio of Discrete Fourier Transform (DFT) coefficients]. In this algorithm, an inverse modulation of sensor signals is performed to detect jumping-off point of LFAC in the time domain; this step is exploited to determine sampling points to be processed. A determination factor is calculated and taken into database to figure out frequency with a binary search algorithm. Experimental results demonstrate that the frequency measurement resolution of the LFAC magnetic field is improved from 12.2 Hz to 0.8 Hz by the presented method, which, within the signal band of a magnetic anomaly (0.04-2 Hz), indicates that the proposed method may expand the applications of magnetoresistive (MR) sensors to human healthcare and magnetic anomaly detection (MAD).

  15. Quantitative Assessment of Detection Frequency for the INL Ambient Air Monitoring Network

    Energy Technology Data Exchange (ETDEWEB)

    Sondrup, A. Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rood, Arthur S. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-11-01

    A quantitative assessment of the Idaho National Laboratory (INL) air monitoring network was performed using frequency of detection as the performance metric. The INL air monitoring network consists of 37 low-volume air samplers in 31 different locations. Twenty of the samplers are located on INL (onsite) and 17 are located off INL (offsite). Detection frequencies were calculated using both BEA and ESER laboratory minimum detectable activity (MDA) levels. The CALPUFF Lagrangian puff dispersion model, coupled with 1 year of meteorological data, was used to calculate time-integrated concentrations at sampler locations for a 1-hour release of unit activity (1 Ci) for every hour of the year. The unit-activity time-integrated concentration (TICu) values were calculated at all samplers for releases from eight INL facilities. The TICu values were then scaled and integrated for a given release quantity and release duration. All facilities modeled a ground-level release emanating either from the center of the facility or at a point where significant emissions are possible. In addition to ground-level releases, three existing stacks at the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and Material and Fuels Complex were also modeled. Meteorological data from the 35 stations comprising the INL Mesonet network, data from the Idaho Falls Regional airport, upper air data from the Boise airport, and three-dimensional gridded data from the weather research forecasting model were used for modeling. Three representative radionuclides identified as key radionuclides in INL’s annual National Emission Standards for Hazardous Air Pollutants evaluations were considered for the frequency of detection analysis: Cs-137 (beta-gamma emitter), Pu-239 (alpha emitter), and Sr-90 (beta emitter). Source-specific release quantities were calculated for each radionuclide, such that the maximum inhalation dose at any publicly accessible sampler or the National

  16. Buried Object Detection Method Using Optimum Frequency Range in Extremely Shallow Underground

    Science.gov (United States)

    Sugimoto, Tsuneyoshi; Abe, Touma

    2011-07-01

    We propose a new detection method for buried objects using the optimum frequency response range of the corresponding vibration velocity. Flat speakers and a scanning laser Doppler vibrometer (SLDV) are used for noncontact acoustic imaging in the extremely shallow underground. The exploration depth depends on the sound pressure, but it is usually less than 10 cm. Styrofoam, wood (silver fir), and acrylic boards of the same size, different size styrofoam boards, a hollow toy duck, a hollow plastic container, a plastic container filled with sand, a hollow steel can and an unglazed pot are used as buried objects which are buried in sand to about 2 cm depth. The imaging procedure of buried objects using the optimum frequency range is given below. First, the standardized difference from the average vibration velocity is calculated for all scan points. Next, using this result, underground images are made using a constant frequency width to search for the frequency response range of the buried object. After choosing an approximate frequency response range, the difference between the average vibration velocity for all points and that for several points that showed a clear response is calculated for the final confirmation of the optimum frequency range. Using this optimum frequency range, we can obtain the clearest image of the buried object. From the experimental results, we confirmed the effectiveness of our proposed method. In particular, a clear image of the buried object was obtained when the SLDV image was unclear.

  17. Design and Implementation of 1-2 GHz Stepped Frequency GPR for Buried Metal Detection

    Directory of Open Access Journals (Sweden)

    Joko Suryana

    2010-10-01

    Full Text Available In this paper, we describe the design and realization steps of 1 - 2 GHz SFGPR (Stepped Frequency Ground Penetrating Radar transceiver for metal detection under the ground. Before using prototyped GPR for detecting the metal under the ground, several of calibration processes must be performed, namely phase calibration and monocycle pulse waveform calibration. After completing the calibrations, this prototyped GPR would be ready for detecting a  hidden object such as a metal plate 5 cm under the ground in our small test range size 25 cm x 75 cm x 10 cm. From the calibration and detection results, we concluded that the prototyped SFGPR passed the technical specifications of the design and could perform the metal detection under the ground with high SNR.

  18. Microwave frequency sensor for detection of biological cells in microfluidic channels.

    Science.gov (United States)

    Nikolic-Jaric, M; Romanuik, S F; Ferrier, G A; Bridges, G E; Butler, M; Sunley, K; Thomson, D J; Freeman, M R

    2009-08-12

    We present details of an apparatus for capacitive detection of biomaterials in microfluidic channels operating at microwave frequencies where dielectric effects due to interfacial polarization are minimal. A circuit model is presented, which can be used to adapt this detection system for use in other microfluidic applications and to identify ones where it would not be suitable. The detection system is based on a microwave coupled transmission line resonator integrated into an interferometer. At 1.5 GHz the system is capable of detecting changes in capacitance of 650 zF with a 50 Hz bandwidth. This system is well suited to the detection of biomaterials in a variety of suspending fluids, including phosphate-buffered saline. Applications involving both model particles (polystyrene microspheres) and living cells-baker's yeast (Saccharomyces cerevisiae) and Chinese hamster ovary cells-are presented.

  19. System and method for constructing filters for detecting signals whose frequency content varies with time

    Science.gov (United States)

    Qian, S.; Dunham, M.E.

    1996-11-12

    A system and method are disclosed for constructing a bank of filters which detect the presence of signals whose frequency content varies with time. The present invention includes a novel system and method for developing one or more time templates designed to match the received signals of interest and the bank of matched filters use the one or more time templates to detect the received signals. Each matched filter compares the received signal x(t) with a respective, unique time template that has been designed to approximate a form of the signals of interest. The robust time domain template is assumed to be of the order of w(t)=A(t)cos(2{pi}{phi}(t)) and the present invention uses the trajectory of a joint time-frequency representation of x(t) as an approximation of the instantaneous frequency function {phi}{prime}(t). First, numerous data samples of the received signal x(t) are collected. A joint time frequency representation is then applied to represent the signal, preferably using the time frequency distribution series. The joint time-frequency transformation represents the analyzed signal energy at time t and frequency f, P(t,f), which is a three-dimensional plot of time vs. frequency vs. signal energy. Then P(t,f) is reduced to a multivalued function f(t), a two dimensional plot of time vs. frequency, using a thresholding process. Curve fitting steps are then performed on the time/frequency plot, preferably using Levenberg-Marquardt curve fitting techniques, to derive a general instantaneous frequency function {phi}{prime}(t) which best fits the multivalued function f(t). Integrating {phi}{prime}(t) along t yields {phi}{prime}(t), which is then inserted into the form of the time template equation. A suitable amplitude A(t) is also preferably determined. Once the time template has been determined, one or more filters are developed which each use a version or form of the time template. 7 figs.

  20. An integrative time-varying frequency detection and channel sounding method for dynamic plasma sheath

    Science.gov (United States)

    Shi, Lei; Yao, Bo; Zhao, Lei; Liu, Xiaotong; Yang, Min; Liu, Yanming

    2018-01-01

    The plasma sheath-surrounded hypersonic vehicle is a dynamic and time-varying medium and it is almost impossible to calculate time-varying physical parameters directly. The in-fight detection of the time-varying degree is important to understand the dynamic nature of the physical parameters and their effect on re-entry communication. In this paper, a constant envelope zero autocorrelation (CAZAC) sequence based on time-varying frequency detection and channel sounding method is proposed to detect the plasma sheath electronic density time-varying property and wireless channel characteristic. The proposed method utilizes the CAZAC sequence, which has excellent autocorrelation and spread gain characteristics, to realize dynamic time-varying detection/channel sounding under low signal-to-noise ratio in the plasma sheath environment. Theoretical simulation under a typical time-varying radio channel shows that the proposed method is capable of detecting time-variation frequency up to 200 kHz and can trace the channel amplitude and phase in the time domain well under -10 dB. Experimental results conducted in the RF modulation discharge plasma device verified the time variation detection ability in practical dynamic plasma sheath. Meanwhile, nonlinear phenomenon of dynamic plasma sheath on communication signal is observed thorough channel sounding result.

  1. Generation, detection and spectroscopic studies of high-frequency nonequilibrium phonons in crystals

    International Nuclear Information System (INIS)

    Dennis, W.M.; Yen, W.M.

    2007-01-01

    In this article we will review studies conducted in the past two decades on the dynamic properties of high-frequency (THz) phonons generated monochromatically with high power far infrared (FIR) laser pulses using defect-induced phonon absorption and detected using a vibronic sideband spectrometer fashioned after that devised by Kaplyanskii, the honoree of this special issue. The temporal and spectral evolution of the phonon signature provides information on the mechanisms that dominate the relaxation of high-frequency phonons in real crystals

  2. Acoustic feedwater heater leak detection: Industry application of low ampersand high frequency detection increases response and reliability

    International Nuclear Information System (INIS)

    Woyshner, W.S.; Bryson, T.; Robertson, M.O.

    1993-01-01

    The Electric Power Research Institute has sponsored research associated with acoustic Feedwater Heater Leak Detection since the early 1980s. Results indicate that this technology is economically beneficial and dependable. Recent research work has employed acoustic sensors and signal conditioning with wider frequency range response and background noise elimination techniques to provide increased accuracy and dependability. Dual frequency sensors have been applied at a few facilities to provide information on this application of dual frequency response. Sensor mounting methods and attenuation due to various mounting configurations are more conclusively understood. These are depicted and discussed in detail. The significance of trending certain plant parameters such as heat cycle flows, heater vent and drain valve position, proper relief valve operation, etc. is also addressed. Test data were collected at various facilities to monitor the effect of varying several related operational parameters. A group of FWHLD Users have been involved from the inception of the project and reports on their latest successes and failures, along with various data depicting early detection of FWHLD tube leaks, will be included. 3 refs., 12 figs., 1 tab

  3. Plants experiencing chronic internal exposure to ionizing radiation exhibit higher frequency of homologous recombination than acutely irradiated plants

    Energy Technology Data Exchange (ETDEWEB)

    Kovalchuk, O.; Kovalchuk, I.; Hohn, B. [Friedrich Miescher Institute, P.O. Box 2543, CH-4002 Basel (Switzerland); Arkhipov, A. [Chernobyl Scientific and Technical Center of International Research, Shkolnaya Str. 6, 255620 Chernobyl (Ukraine); Barylyak, I.; Karachov, I. [Ukrainian Scientific Genetics Center, Popudrenko Str. 50, 253660 Kiev (Ukraine); Titov, V. [Ivano-Frankivsk State Medical Academy, Galitska Str.2, 284000 Ivano-Frankivsk (Ukraine)

    2000-04-03

    different chemical composition, but equal radioactivity, exhibited different levels of HR, dependent upon the absorbed dose of radiation. Remarkably, we observed a much higher frequency of HR in plants exposed to chronic irradiation when compared to acutely irradiated plants. Although acute application of 0.1-0.5 Gy did not lead to an increase of frequency of HR, the chronic exposure of the plants to several orders of magnitude lower dose of 200 {mu}Gy led to a 5-6-fold induction of the frequency of HR as compared to the control.

  4. Active sources in the cutoff of centrifugal fans to reduce the blade tones at higher-order duct mode frequencies

    Science.gov (United States)

    Neise, W.; Koopmann, G. H.

    1991-01-01

    A previously developed (e.g., Neise and Koopmann, 1984; Koopmann et al., 1988) active noise control technique in which the unwanted acoustic signals from centrifugal fans are suppressed by placing two externally driven sources near the cutoff of the casing was applied to the frequency region where not only plane sound waves are propagational in the fan ducts but also higher-order acoustic modes. Using a specially designed fan noise testing facility, the performance of two fans (280-mm impeller diam and 508 mm diam) was monitored with static pressure taps mounted peripherally around the inlet nozzle. Experimental results show that the aerodynamically generated source pressure field around the cutoff is too complex to be successfully counterimaged by only two active sources introduced in this region. It is suggested that, for an efficient application of this noise control technique in the higher-order mode frequency regime, it is neccessary to use an active source involving larger number of individually driven loudspeakers.

  5. Detection of Fatigue Damage by Using High Frequency Nonlinear Laser Ultrasonic Signals

    International Nuclear Information System (INIS)

    Park, Seung Kyu; Park, Nak Kyu; Baik, Sung Hoon; Cheong, Yong Moo; Cha, Byung Heon

    2012-01-01

    The detection of fatigue damage for the components of a nuclear power plant is one of key techniques to prevent a catastrophic accident and the subsequent severe losses. Specifically, it is preferred to detect at an early stage of the fatigue damage. If the fatigue damage that is in danger of growing into a fracture is accurately detected, an appropriate treatment could be carried out to improve the condition. Although most engineers and designers take precautions against fatigue, some breakdowns of nuclear power plant components still occur due to fatigue damage. It is considered that ultrasound testing technique is the most promising method to detect the fatigue damage in many nondestructive testing methods. Laser ultrasound has attracted attention as a noncontact testing technique. Especially, laser ultrasonic signal has wide band frequency spectrum which can provide more accurate information for a testing material. The conventional linear ultrasonic technique is sensitive to gross defects or opened cracks whereas it is less sensitive to evenly distributed micro-cracks or degradation. An alternative technique to overcome this limitation is nonlinear ultrasound. The principal difference between linear and nonlinear technique is that in the latter the existence and characteristics of defects are often related to an acoustic signal whose frequency differs from that of the input signal. This is related to the radiation and propagation of finite amplitude, especially high power, ultrasound and its interaction with discontinuities, such as cracks, interfaces and voids. Since material failure or degradation is usually preceded by some kind of nonlinear mechanical behavior before significant plastic deformation or material damage occurs. The presence of nonlinear terms in the wave equation causes intense acoustic waves to generate new waves at frequencies which are multiples of the initial sound wave frequency. The nonlinear effect can exert a strong effect on the

  6. Optimising 4-D surface change detection: an approach for capturing rockfall magnitude-frequency

    Science.gov (United States)

    Williams, Jack G.; Rosser, Nick J.; Hardy, Richard J.; Brain, Matthew J.; Afana, Ashraf A.

    2018-02-01

    We present a monitoring technique tailored to analysing change from near-continuously collected, high-resolution 3-D data. Our aim is to fully characterise geomorphological change typified by an event magnitude-frequency relationship that adheres to an inverse power law or similar. While recent advances in monitoring have enabled changes in volume across more than 7 orders of magnitude to be captured, event frequency is commonly assumed to be interchangeable with the time-averaged event numbers between successive surveys. Where events coincide, or coalesce, or where the mechanisms driving change are not spatially independent, apparent event frequency must be partially determined by survey interval.The data reported have been obtained from a permanently installed terrestrial laser scanner, which permits an increased frequency of surveys. Surveying from a single position raises challenges, given the single viewpoint onto a complex surface and the need for computational efficiency associated with handling a large time series of 3-D data. A workflow is presented that optimises the detection of change by filtering and aligning scans to improve repeatability. An adaptation of the M3C2 algorithm is used to detect 3-D change to overcome data inconsistencies between scans. Individual rockfall geometries are then extracted and the associated volumetric errors modelled. The utility of this approach is demonstrated using a dataset of ˜ 9 × 103 surveys acquired at ˜ 1 h intervals over 10 months. The magnitude-frequency distribution of rockfall volumes generated is shown to be sensitive to monitoring frequency. Using a 1 h interval between surveys, rather than 30 days, the volume contribution from small (< 0.1 m3) rockfalls increases from 67 to 98 % of the total, and the number of individual rockfalls observed increases by over 3 orders of magnitude. High-frequency monitoring therefore holds considerable implications for magnitude-frequency derivatives, such as hazard return

  7. Optimising 4-D surface change detection: an approach for capturing rockfall magnitude–frequency

    Directory of Open Access Journals (Sweden)

    J. G. Williams

    2018-02-01

    Full Text Available We present a monitoring technique tailored to analysing change from near-continuously collected, high-resolution 3-D data. Our aim is to fully characterise geomorphological change typified by an event magnitude–frequency relationship that adheres to an inverse power law or similar. While recent advances in monitoring have enabled changes in volume across more than 7 orders of magnitude to be captured, event frequency is commonly assumed to be interchangeable with the time-averaged event numbers between successive surveys. Where events coincide, or coalesce, or where the mechanisms driving change are not spatially independent, apparent event frequency must be partially determined by survey interval.The data reported have been obtained from a permanently installed terrestrial laser scanner, which permits an increased frequency of surveys. Surveying from a single position raises challenges, given the single viewpoint onto a complex surface and the need for computational efficiency associated with handling a large time series of 3-D data. A workflow is presented that optimises the detection of change by filtering and aligning scans to improve repeatability. An adaptation of the M3C2 algorithm is used to detect 3-D change to overcome data inconsistencies between scans. Individual rockfall geometries are then extracted and the associated volumetric errors modelled. The utility of this approach is demonstrated using a dataset of  ∼  9  ×  103 surveys acquired at  ∼  1 h intervals over 10 months. The magnitude–frequency distribution of rockfall volumes generated is shown to be sensitive to monitoring frequency. Using a 1 h interval between surveys, rather than 30 days, the volume contribution from small (< 0.1 m3 rockfalls increases from 67 to 98 % of the total, and the number of individual rockfalls observed increases by over 3 orders of magnitude. High-frequency monitoring therefore holds considerable

  8. Boxcar detection for high-frequency modulation in stimulated Raman scattering microscopy

    Science.gov (United States)

    Fimpel, P.; Riek, C.; Ebner, L.; Leitenstorfer, A.; Brida, D.; Zumbusch, A.

    2018-04-01

    Stimulated Raman scattering (SRS) microscopy is an important non-linear optical technique for the investigation of unlabeled samples. The SRS signal manifests itself as a small intensity exchange between the laser pulses involved in coherent excitation of Raman modes. Usually, high-frequency modulation is applied in one pulse train, and the signal is then detected on the other pulse train via lock-in amplification. While allowing shot-noise limited detection sensitivity, lock-in detection, which corresponds to filtering the signal in the frequency domain, is not the most efficient way of using the excitation light. In this manuscript, we show that boxcar averaging, which is equivalent to temporal filtering, is better suited for the detection of low-duty-cycle signals as encountered in SRS microscopy. We demonstrate that by employing suitable gating windows, the signal-to-noise ratios achievable with lock-in detection can be realized in shorter time with boxcar averaging. Therefore, high-quality images are recorded at a faster rate and lower irradiance which is an important factor, e.g., for minimizing degradation of biological samples.

  9. Detection of Traveling Ionospheric Disturbances by Medium Frequency Doppler Sounding Using AM Radio Transmissions

    Science.gov (United States)

    Chilcote, M. A.; Labelle, J. W.; Lind, F. D.; Coster, A. J.; Galkin, I. A.; Miller, E.; Weatherwax, A. T.

    2013-12-01

    Nighttime traveling ionosphere disturbances (TIDs) propagating in the lower F region of the ionosphere were detected from time variations in the Doppler shifts of commercial AM radio broadcast stations. Three separately deployed receivers, components of the Intercepted Signals for Ionospheric Science (ISIS) Array software radio instrumentation network, recorded signals from two radio stations during eleven nights in March-April, 2012. Combining these measurements established that variations in the frequencies of the received signals, with amplitudes up to a few tenths of a Hertz, resulted from Doppler shifts produced by the ionosphere. At times, TIDs were detected as large amplitude variations in the Doppler shift with approximately 40-minute period correlated across the array. For one study interval, 0000-0400 UT on April 13, 2012, simultaneous GPS-TEC, digisonde, and superDARN coherent backscatter radar measurements confirmed the detection of TIDs with the same period. Detection of the AM signals at widely spaced receivers allowed the phase velocity and wavelength of the TIDs to be inferred, with some limitations due to differing reflection heights for the different frequencies. These measurements will be compared to phase velocities and wavelengths determined from combining an array of GPS receivers; discrepancies due to the altitude sensitivity of the techniques or other effects will be discussed. These results demonstrate that AM radio signals can be used for detection of nighttime TIDs.

  10. Use of Time- and Frequency-Domain Approaches for Damage Detection in Civil Engineering Structures

    Directory of Open Access Journals (Sweden)

    V. H. Nguyen

    2014-01-01

    Full Text Available The aim of this paper is to apply both time- and frequency-domain-based approaches on real-life civil engineering structures and to assess their capability for damage detection. The methodology is based on Principal Component Analysis of the Hankel matrix built from output-only measurements and of Frequency Response Functions. Damage detection is performed using the concept of subspace angles between a current (possibly damaged state and a reference (undamaged state. The first structure is the Champangshiehl Bridge located in Luxembourg. Several damage levels were intentionally created by cutting a growing number of prestressed tendons and vibration data were acquired by the University of Luxembourg for each damaged state. The second example consists in reinforced and prestressed concrete panels. Successive damages were introduced in the panels by loading heavy weights and by cutting steel wires. The illustrations show different consequences in damage identification by the considered techniques.

  11. The Effect of the Different Frequency on Skin Depth of GPR Detection

    Directory of Open Access Journals (Sweden)

    Mohammed Mejbel Salih

    2017-05-01

    Full Text Available Today the utilization of Ground Penetration Radar are increasing with development civil works , the requirement is increase a low cost technique, time and accuracy, all these should be founded in same time to achieve the project with fullest. In this study will use GPR instrument with three frequency(500,800,1000 MHz,and applying the experiments in various medium with different object's materials for pipe that expected founded object underground for the purpose of extract the fixed data that serve who work interest in this field. This technique will help in solve problem of underground detection ,such as water leakage in underground pipe for different depth that considered complex and expensive problem in same time in urban life .The study contribute in solve issue of utilizing the suitable frequency with penetration for detection, this is clarify through the result gotten that refer to excellent outcome.

  12. Islanding Detection of Synchronous Machine-Based DGs using Average Frequency Based Index

    Directory of Open Access Journals (Sweden)

    M. Bakhshi

    2013-06-01

    Full Text Available Identification of intentional and unintentional islanding situations of dispersed generators (DGs is one of the most important protection concerns in power systems. Considering safety and reliability problems of distribution networks, an exact diagnosis index is required to discriminate the loss of the main network from the existing parallel operation. Hence, this paper introduces a new islanding detection method for synchronous machine–based DGs. This method uses the average value of the generator frequency to calculate a new detection index. The proposed method is an effective supplement of the over/under frequency protection (OFP/UFP system. The analytical equations and simulation results are used to assess the performance of the proposed method under various scenarios such as different types of faults, load changes and capacitor bank switching. To show the effectiveness of the proposed method, it is compared with the performance of both ROCOF and ROCOFOP methods.

  13. Fault detection in finite frequency domain for Takagi-Sugeno fuzzy systems with sensor faults.

    Science.gov (United States)

    Li, Xiao-Jian; Yang, Guang-Hong

    2014-08-01

    This paper is concerned with the fault detection (FD) problem in finite frequency domain for continuous-time Takagi-Sugeno fuzzy systems with sensor faults. Some finite-frequency performance indices are initially introduced to measure the fault/reference input sensitivity and disturbance robustness. Based on these performance indices, an effective FD scheme is then presented such that the generated residual is designed to be sensitive to both fault and reference input for faulty cases, while robust against the reference input for fault-free case. As the additional reference input sensitivity for faulty cases is considered, it is shown that the proposed method improves the existing FD techniques and achieves a better FD performance. The theory is supported by simulation results related to the detection of sensor faults in a tunnel-diode circuit.

  14. Selectivity enhancement in photoacoustic gas analysis via phase-sensitive detection at high modulation frequency

    Science.gov (United States)

    Kosterev, Anatoliy (Inventor)

    2010-01-01

    A method for detecting a target fluid in a fluid sample comprising a first fluid and the target fluid using photoacoustic spectroscopy (PAS), comprises a) providing a light source configured to introduce an optical signal having at least one wavelength into the fluid sample; b) modulating the optical signal at a desired modulation frequency such that the optical signal generates an acoustic signal in the fluid sample; c) measuring the acoustic signal in a resonant acoustic detector; and d) using the phase of the acoustic signal to detect the presence of the target fluid.

  15. Internal Rot Detection with the Use of Low-Frequency Flaw Detector

    Science.gov (United States)

    Proskórnicki, Marek; Ligus, Grzegorz

    2014-12-01

    The issue of rot detection in standing timber or stocked wood is very important in forest management. Rot flaw detection used for that purpose is represented by invasive and non-invasive devices. Non-invasive devices are very accurate, but due to the cost and complicated operation they have not been applied on a large scale in forest management. Taking into account the practical needs of foresters a prototype of low-frequency flaw was developed. The principle of its operation is based on the difference in acoustic wave propagation in sound wood and wood with rot.

  16. Aircraft Detection from VHR Images Based on Circle-Frequency Filter and Multilevel Features

    Directory of Open Access Journals (Sweden)

    Feng Gao

    2013-01-01

    Full Text Available Aircraft automatic detection from very high-resolution (VHR images plays an important role in a wide variety of applications. This paper proposes a novel detector for aircraft detection from very high-resolution (VHR remote sensing images. To accurately distinguish aircrafts from background, a circle-frequency filter (CF-filter is used to extract the candidate locations of aircrafts from a large size image. A multi-level feature model is then employed to represent both local appearance and spatial layout of aircrafts by means of Robust Hue Descriptor and Histogram of Oriented Gradients. The experimental results demonstrate the superior performance of the proposed method.

  17. Detection and Classification of Low Probability of Intercept Radar Signals Using Parallel Filter Arrays and Higher Order Statistics

    National Research Council Canada - National Science Library

    Taboada, Fernando

    2002-01-01

    Low probability of intercept (LPI) is that property of an emitter that because of its low power, wide bandwidth, frequency variability, or other design attributes, makes it difficult to be detected or identified by means of passive...

  18. How does higher frequency monitoring data affect the calibration of a process-based water quality model?

    Science.gov (United States)

    Jackson-Blake, Leah; Helliwell, Rachel

    2015-04-01

    Process-based catchment water quality models are increasingly used as tools to inform land management. However, for such models to be reliable they need to be well calibrated and shown to reproduce key catchment processes. Calibration can be challenging for process-based models, which tend to be complex and highly parameterised. Calibrating a large number of parameters generally requires a large amount of monitoring data, spanning all hydrochemical conditions. However, regulatory agencies and research organisations generally only sample at a fortnightly or monthly frequency, even in well-studied catchments, often missing peak flow events. The primary aim of this study was therefore to investigate how the quality and uncertainty of model simulations produced by a process-based, semi-distributed catchment model, INCA-P (the INtegrated CAtchment model of Phosphorus dynamics), were improved by calibration to higher frequency water chemistry data. Two model calibrations were carried out for a small rural Scottish catchment: one using 18 months of daily total dissolved phosphorus (TDP) concentration data, another using a fortnightly dataset derived from the daily data. To aid comparability, calibrations were carried out automatically using the Markov Chain Monte Carlo - DiffeRential Evolution Adaptive Metropolis (MCMC-DREAM) algorithm. Calibration to daily data resulted in improved simulation of peak TDP concentrations and improved model performance statistics. Parameter-related uncertainty in simulated TDP was large when fortnightly data was used for calibration, with a 95% credible interval of 26 μg/l. This uncertainty is comparable in size to the difference between Water Framework Directive (WFD) chemical status classes, and would therefore make it difficult to use this calibration to predict shifts in WFD status. The 95% credible interval reduced markedly with the higher frequency monitoring data, to 6 μg/l. The number of parameters that could be reliably auto

  19. Comparison of three cell block techniques for detection of low frequency abnormal cells

    OpenAIRE

    McCormack M; Hecht SA

    2013-01-01

    Steven A Hecht, Matthew McCormackHologic Inc, Marlborough, MA, USABackground: The Cellient® Automated Cell Block System rapidly creates paraffin-embedded cell blocks by using vacuum filtration to deposit a layer of cells on a filter and infiltrate those cells with reagents and paraffin. This study used a “tracer” cell model to mimic low frequency abnormal cells and compare detection and representative sampling with simple sedimentation, Richard-Allan HistoGel&t...

  20. An automatized frequency analysis for vine plot detection and delineation in remote sensing

    OpenAIRE

    Delenne , Carole; Rabatel , G.; Deshayes , M.

    2008-01-01

    The availability of an automatic tool for vine plot detection, delineation, and characterization would be very useful for management purposes. An automatic and recursive process using frequency analysis (with Fourier transform and Gabor filters) has been developed to meet this need. This results in the determination of vine plot boundary and accurate estimation of interrow width and row orientation. To foster large-scale applications, tests and validation have been carried out on standard ver...

  1. Feasibility of Detecting Natural Frequencies of Hydraulic Turbines While in Operation, Using Strain Gauges.

    Science.gov (United States)

    Valentín, David; Presas, Alexandre; Bossio, Matias; Egusquiza, Mònica; Egusquiza, Eduard; Valero, Carme

    2018-01-10

    Nowadays, hydropower plays an essential role in the energy market. Due to their fast response and regulation capacity, hydraulic turbines operate at off-design conditions with a high number of starts and stops. In this situation, dynamic loads and stresses over the structure are high, registering some failures over time, especially in the runner. Therefore, it is important to know the dynamic response of the runner while in operation, i.e., the natural frequencies, damping and mode shapes, in order to avoid resonance and fatigue problems. Detecting the natural frequencies of hydraulic turbine runners while in operation is challenging, because they are inaccessible structures strongly affected by their confinement in water. Strain gauges are used to measure the stresses of hydraulic turbine runners in operation during commissioning. However, in this paper, the feasibility of using them to detect the natural frequencies of hydraulic turbines runners while in operation is studied. For this purpose, a large Francis turbine runner (444 MW) was instrumented with several strain gauges at different positions. First, a complete experimental strain modal testing (SMT) of the runner in air was performed using the strain gauges and accelerometers. Then, the natural frequencies of the runner were estimated during operation by means of analyzing accurately transient events or rough operating conditions.

  2. A Frequency-Weighted Energy Operator and complementary ensemble empirical mode decomposition for bearing fault detection

    Science.gov (United States)

    Imaouchen, Yacine; Kedadouche, Mourad; Alkama, Rezak; Thomas, Marc

    2017-01-01

    Signal processing techniques for non-stationary and noisy signals have recently attracted considerable attentions. Among them, the empirical mode decomposition (EMD) which is an adaptive and efficient method for decomposing signals from high to low frequencies into intrinsic mode functions (IMFs). Ensemble EMD (EEMD) is proposed to overcome the mode mixing problem of the EMD. In the present paper, the Complementary EEMD (CEEMD) is used for bearing fault detection. As a noise-improved method, the CEEMD not only overcomes the mode mixing, but also eliminates the residual of added white noise persisting into the IMFs and enhance the calculation efficiency of the EEMD method. Afterward, a selection method is developed to choose relevant IMFs containing information about defects. Subsequently, a signal is reconstructed from the sum of relevant IMFs and a Frequency-Weighted Energy Operator is tailored to extract both the amplitude and frequency modulations from the selected IMFs. This operator outperforms the conventional energy operator and the enveloping methods, especially in the presence of strong noise and multiple vibration interferences. Furthermore, simulation and experimental results showed that the proposed method improves performances for detecting the bearing faults. The method has also high computational efficiency and is able to detect the fault at an early stage of degradation.

  3. Detection beyond the Debye screening length in a high-frequency nanoelectronic biosensor.

    Science.gov (United States)

    Kulkarni, Girish S; Zhong, Zhaohui

    2012-02-08

    Nanosensors based on the unique electronic properties of nanotubes and nanowires offer high sensitivity and have the potential to revolutionize the field of Point-of-Care (POC) medical diagnosis. The direct current (dc) detection of a wide array of organic and inorganic molecules has been demonstrated on these devices. However, sensing mechanism based on measuring changes in dc conductance fails at high background salt concentrations, where the sensitivity of the devices suffers from the ionic screening due to mobile ions present in the solution. Here, we successfully demonstrate that the fundamental ionic screening effect can be mitigated by operating single-walled carbon nanotube field effect transistor as a high-frequency biosensor. The nonlinear mixing between the alternating current excitation field and the molecular dipole field can generate mixing current sensitive to the surface-bound biomolecules. Electrical detection of monolayer streptavidin binding to biotin in 100 mM buffer solution is achieved at a frequency beyond 1 MHz. Theoretical modeling confirms improved sensitivity at high frequency through mitigation of the ionic screening effect. The results should promise a new biosensing platform for POC detection, where biosensors functioning directly in physiologically relevant condition are desired. © 2012 American Chemical Society

  4. Spectrally efficient polarization multiplexed direct-detection OFDM system without frequency gap.

    Science.gov (United States)

    Wei, Chia-Chien; Zeng, Wei-Siang; Lin, Chun-Ting

    2016-01-25

    We experimentally demonstrate a spectrally efficient direct-detection orthogonal frequency-division multiplexing (DD-OFDM) system. In addition to polarization-division multiplexing, removing the frequency gap further improves the spectral efficiency of the OFDM system. The frequency gap between a reference carrier and OFDM subcarriers avoids subcarrier-to-subcarrier beating interference (SSBI) in traditional DD-OFDM systems. Without dynamic polarization control, the resulting interference after square-law direct detection in the proposed gap-less system is polarization-dependent and composed of linear inter-carrier interference (ICI) and nonlinear SSBI. Thus, this work proposes an iterative multiple-input multiple-output detection scheme to remove the mixed polarization-dependent interference. Compared to the previous scheme, which only removes ICI, the proposed scheme can further eliminate SSBI to achieve the improvement of ∼ 7 dB in signal-to-noise ratio. Without the need for polarization control, we successfully utilize 7-GHz bandwidth to transmit a 39.5-Gbps polarization multiplexed OFDM signal over 100 km.

  5. Sonic IR crack detection of aircraft turbine engine blades with multi-frequency ultrasound excitations

    International Nuclear Information System (INIS)

    Zhang, Ding; Han, Xiaoyan; Newaz, Golam

    2014-01-01

    Effectively and accurately detecting cracks or defects in critical engine components, such as turbine engine blades, is very important for aircraft safety. Sonic Infrared (IR) Imaging is such a technology with great potential for these applications. This technology combines ultrasound excitation and IR imaging to identify cracks and flaws in targets. In general, failure of engine components, such as blades, begins with tiny cracks. Since the attenuation of the ultrasound wave propagation in turbine engine blades is small, the efficiency of crack detection in turbine engine blades can be quite high. The authors at Wayne State University have been developing the technology as a reliable tool for the future field use in aircraft engines and engine parts. One part of the development is to use finite element modeling to assist our understanding of effects of different parameters on crack heating while experimentally hard to achieve. The development has been focused with single frequency ultrasound excitation and some results have been presented in a previous conference. We are currently working on multi-frequency excitation models. The study will provide results and insights of the efficiency of different frequency excitation sources to foster the development of the technology for crack detection in aircraft engine components

  6. An Islanding Detection Method by Using Frequency Positive Feedback Based on FLL for Single-Phase Microgrid

    DEFF Research Database (Denmark)

    Sun, Qinfei; Guerrero, Josep M.; Jing, Tianjun

    2017-01-01

    An active islanding detection method based on Frequency-Locked Loop (FLL) for constant power controlled inverter in single-phase microgrid is proposed. This method generates a phase shift comparing the instantaneous frequency obtained from FLL unit with the nominal frequency to modify the reference...

  7. RareVar: A Framework for Detecting Low-Frequency Single-Nucleotide Variants.

    Science.gov (United States)

    Hao, Yangyang; Xuei, Xiaoling; Li, Lang; Nakshatri, Harikrishna; Edenberg, Howard J; Liu, Yunlong

    2017-07-01

    Accurate identification of low-frequency somatic point mutations in tumor samples has important clinical utilities. Although high-throughput sequencing technology enables capturing such variants while sequencing primary tumor samples, our ability for accurate detection is compromised when the variant frequency is close to the sequencer error rate. Most current experimental and bioinformatic strategies target mutations with ≥5% allele frequency, which limits our ability to understand the cancer etiology and tumor evolution. We present an experimental and computational modeling framework, RareVar, to reliably identify low-frequency single-nucleotide variants from high-throughput sequencing data under standard experimental protocols. RareVar protocol includes a benchmark design by pooling DNAs from already sequenced individuals at various concentrations to target variants at desired frequencies, 0.5%-3% in our case. By applying a generalized, linear model-based, position-specific error model, followed by machine-learning-based variant calibration, our approach outperforms existing methods. Our method can be applied on most capture and sequencing platforms without modifying the experimental protocol.

  8. Frequency Mixing Magnetic Detection Scanner for Imaging Magnetic Particles in Planar Samples.

    Science.gov (United States)

    Hong, Hyobong; Lim, Eul-Gyoon; Jeong, Jae-Chan; Chang, Jiho; Shin, Sung-Woong; Krause, Hans-Joachim

    2016-06-09

    The setup of a planar Frequency Mixing Magnetic Detection (p-FMMD) scanner for performing Magnetic Particles Imaging (MPI) of flat samples is presented. It consists of two magnetic measurement heads on both sides of the sample mounted on the legs of a u-shaped support. The sample is locally exposed to a magnetic excitation field consisting of two distinct frequencies, a stronger component at about 77 kHz and a weaker field at 61 Hz. The nonlinear magnetization characteristics of superparamagnetic particles give rise to the generation of intermodulation products. A selected sum-frequency component of the high and low frequency magnetic field incident on the magnetically nonlinear particles is recorded by a demodulation electronics. In contrast to a conventional MPI scanner, p-FMMD does not require the application of a strong magnetic field to the whole sample because mixing of the two frequencies occurs locally. Thus, the lateral dimensions of the sample are just limited by the scanning range and the supports. However, the sample height determines the spatial resolution. In the current setup it is limited to 2 mm. As examples, we present two 20 mm × 25 mm p-FMMD images acquired from samples with 1 µm diameter maghemite particles in silanol matrix and with 50 nm magnetite particles in aminosilane matrix. The results show that the novel MPI scanner can be applied for analysis of thin biological samples and for medical diagnostic purposes.

  9. Structural Damage Detection Using Changes in Natural Frequencies: Theory and Applications

    Science.gov (United States)

    He, K.; Zhu, W. D.

    2011-07-01

    A vibration-based method that uses changes in natural frequencies of a structure to detect damage has advantages over conventional nondestructive tests in detecting various types of damage, including loosening of bolted joints, using minimum measurement data. Two major challenges associated with applications of the vibration-based damage detection method to engineering structures are addressed: accurate modeling of structures and the development of a robust inverse algorithm to detect damage, which are defined as the forward and inverse problems, respectively. To resolve the forward problem, new physics-based finite element modeling techniques are developed for fillets in thin-walled beams and for bolted joints, so that complex structures can be accurately modeled with a reasonable model size. To resolve the inverse problem, a logistical function transformation is introduced to convert the constrained optimization problem to an unconstrained one, and a robust iterative algorithm using a trust-region method, called the Levenberg-Marquardt method, is developed to accurately detect the locations and extent of damage. The new methodology can ensure global convergence of the iterative algorithm in solving under-determined system equations and deal with damage detection problems with relatively large modeling error and measurement noise. The vibration-based damage detection method is applied to various structures including lightning masts, a space frame structure and one of its components, and a pipeline. The exact locations and extent of damage can be detected in the numerical simulation where there is no modeling error and measurement noise. The locations and extent of damage can be successfully detected in experimental damage detection.

  10. Structural Damage Detection Using Changes in Natural Frequencies: Theory and Applications

    International Nuclear Information System (INIS)

    He, K; Zhu, W D

    2011-01-01

    A vibration-based method that uses changes in natural frequencies of a structure to detect damage has advantages over conventional nondestructive tests in detecting various types of damage, including loosening of bolted joints, using minimum measurement data. Two major challenges associated with applications of the vibration-based damage detection method to engineering structures are addressed: accurate modeling of structures and the development of a robust inverse algorithm to detect damage, which are defined as the forward and inverse problems, respectively. To resolve the forward problem, new physics-based finite element modeling techniques are developed for fillets in thin-walled beams and for bolted joints, so that complex structures can be accurately modeled with a reasonable model size. To resolve the inverse problem, a logistical function transformation is introduced to convert the constrained optimization problem to an unconstrained one, and a robust iterative algorithm using a trust-region method, called the Levenberg-Marquardt method, is developed to accurately detect the locations and extent of damage. The new methodology can ensure global convergence of the iterative algorithm in solving under-determined system equations and deal with damage detection problems with relatively large modeling error and measurement noise. The vibration-based damage detection method is applied to various structures including lightning masts, a space frame structure and one of its components, and a pipeline. The exact locations and extent of damage can be detected in the numerical simulation where there is no modeling error and measurement noise. The locations and extent of damage can be successfully detected in experimental damage detection.

  11. Recent sediment dynamics in hadal trenches: Evidence for the influence of higher-frequency (tidal, near-inertial) fluid dynamics

    DEFF Research Database (Denmark)

    Turnewitsch, Robert; Falahat, Saeed; Stehlikova, Jirina

    2014-01-01

    finds evidence for another mechanism that is superimposed on, and counteracts, the focussing mechanism. This superimposed mechanism is related to higher-frequency (tidal, near-inertial) fluid dynamics. In particular, there is evidence for a strong and negative relation between the intensity...... but significant influence on particulate-matter dynamics and food supply in hadal trenches in particular, but possibly also in the deep seas in general. A mechanism for the influence of internal tides on sediment dynamics is proposed. (C) 2014 Elsevier Ltd. All rights reserved.......In addition to high hydrostatic pressure, scarcity of food is viewed as a factor that limits the abundance and activity of heterotrophic organisms at great ocean depths, including hadal trenches. Supply of nutritious food largely relies on the flux of organic-rich particulate matter from...

  12. Poor glycemic control of diabetes mellitus is associated with higher risk of prostate cancer detection in a biopsy population.

    Directory of Open Access Journals (Sweden)

    Juhyun Park

    Full Text Available To evaluate the impact of glycemic control of diabetes mellitus (DM on prostate cancer detection in a biopsy population.We retrospectively reviewed the records of 1,368 men who underwent prostate biopsy at our institution. We divided our biopsy population into three groups according to their history of DM, and their Hemoglobin A1c (HbA1c level: a no-DM (DM- group; a good glycemic control (DM+GC group (HbA1c <6.5%; and a poor glycemic control (DM+PC group (HbA1c ≥6.5%. For sub-analyses, the DM+PC group was divided into a moderately poor glycemic control (DM+mPC group (6.5≤ HbA1c <7.5% and a severely poor glycemic control (DM+sPC group (HbA1c ≥7.5%.Among 1,368 men, 338 (24.7% had a history of DM, and 393 (28.7% had a positive biopsy. There was a significant difference in prostatic specific antigen density (PSAD (P = 0.037 and the frequency of abnormal DRE findings (P = 0.031 among three groups. The occurrence rate of overall prostate cancer (P<0.001 and high-grade prostate cancer (P = 0.016 also presented with a significantly difference. In the multivariate analysis, the DM+PC group was significantly associated with a higher rate of overall prostate cancer detection in biopsy subjects compared to the DM- group (OR = 2.313, P = 0.001 but the DM+PC group was not associated with a higher rate of high-grade (Gleason score ≥7 diseases detected during the biopsy (OR = 1.297, P = 0.376. However, in subgroup analysis, DM+sPC group was significantly related to a higher risk of high-grade diseases compared to the DM- group (OR = 2.446, P = 0.048.Poor glycemic control of DM was associated with a higher risk of prostate cancer detection, including high-grade disease, in the biopsy population.

  13. Transmission of High Frequency Vibrations in Rotating Systems. Application to Cavitation Detection in Hydraulic Turbines

    Directory of Open Access Journals (Sweden)

    David Valentín

    2018-03-01

    Full Text Available One of the main causes of damage in hydraulic turbines is cavitation. While not all cavitation appearing in a turbine is of a destructive type, erosive cavitation can severely affect the structure, thus increasing maintenance costs and reducing the remaining useful life of the machine. Of all types of cavitation, the maximum erosion occurs when clouds of bubbles collapse on the runner surface (cloud cavitation. When this occurs it is associated with a substantial increase in noise, and vibrations that are propagated everywhere throughout the machine. The generation of these cavitation clouds may occur naturally or it may be the response to a periodic pressure fluctuation, like the rotor/stator interaction in a hydraulic turbine. Erosive bubble cavitation generates high-frequency vibrations that are modulated by the shedding frequency. Therefore, the methods for the detection of erosive cavitation in hydraulic turbines are based on the measurement and demodulation of high-frequency vibrations. In this paper, the feasibility of detecting erosive cavitation in hydraulic turbines is investigated experimentally in a rotating disk system, which represents a simplified hydraulic turbine structure. The test rig used consists of a rotating disk submerged in a tank of water and confined with nearby axial and radial rigid surfaces. The excitation patterns produced by cloud cavitation are reproduced with a PZT (piezoelectric patch located on the disk. These patterns include pseudo-random excitations of different frequency bands modulated by one low carrier frequency, which model the erosive cavitation characteristics. Different types of sensors have been placed in the stationary and in the rotating parts (accelerometers, acoustic emission (AE, and a microphone in order to detect the excitation pattern. The results obtained for all the sensors tested have been compared in detail for the different excitation patterns applied to the disk. With this information

  14. Bearings fault detection in helicopters using frequency readjustment and cyclostationary analysis

    Science.gov (United States)

    Girondin, Victor; Pekpe, Komi Midzodzi; Morel, Herve; Cassar, Jean-Philippe

    2013-07-01

    The objective of this paper is to propose a vibration-based automated framework dealing with local faults occurring on bearings in the transmission of a helicopter. The knowledge of the shaft speed and kinematic computation provide theoretical frequencies that reveal deteriorations on the inner and outer races, on the rolling elements or on the cage. In practice, the theoretical frequencies of bearing faults may be shifted. They may also be masked by parasitical frequencies because the numerous noisy vibrations and the complexity of the transmission mechanics make the signal spectrum very profuse. Consequently, detection methods based on the monitoring of the theoretical frequencies may lead to wrong decisions. In order to deal with this drawback, we propose to readjust the fault frequencies from the theoretical frequencies using the redundancy introduced by the harmonics. The proposed method provides the confidence index of the readjusted frequency. Minor variations in shaft speed may induce random jitters. The change of the contact surface or of the transmission path brings also a random component in amplitude and phase. These random components in the signal destroy spectral localization of frequencies and thus hide the fault occurrence in the spectrum. Under the hypothesis that these random signals can be modeled as cyclostationary signals, the envelope spectrum can reveal that hidden patterns. In order to provide an indicator estimating fault severity, statistics are proposed. They make the hypothesis that the harmonics at the readjusted frequency are corrupted with an additive normally distributed noise. In this case, the statistics computed from the spectra are chi-square distributed and a signal-to-noise indicator is proposed. The algorithms are then tested with data from two test benches and from flight conditions. The bearing type and the radial load are the main differences between the experiences on the benches. The fault is mainly visible in the

  15. Enhanced detection of gametocytes by magnetic deposition microscopy predicts higher potential for Plasmodium falciparum transmission

    Directory of Open Access Journals (Sweden)

    Zborowski Maciej

    2008-04-01

    Full Text Available Abstract Background Aggregated haemozoin crystals within malaria-infected erythrocytes confer susceptibility of parasitized cells to a magnetic field. Here the utility of this method for diagnosis of human malaria is evaluated in a malaria-endemic region of Papua New Guinea (PNG. Methods and findings Individuals with Plasmodium falciparum malaria symptoms (n = 55 provided samples for conventional blood smear (CBS and magnetic deposition microscopy (MDM diagnosis. Standard Giemsa staining and light microscopy was performed to evaluate all preparations. Plasmodium falciparum parasitaemia observed on MDM slides was consistently higher than parasitaemia observed by (CBS for ring (CBS = 2.6 vs. MDM = 3.4%; t-test P-value = 0.13, trophozoite (CBS = 0.5 vs. MDM = 1.6%; t-test P-value = 0.01, schizont (CBS = 0.003 vs. MDM = 0.1%; t-test P-value = 0.08 and gametocyte (CBS = 0.001 vs. MDM = 0.4%; t-test P-value = 0.0002 parasitaemias. Gametocyte prevalence determined by CBS compared to MDM increased from 7.3% to 45%, respectively. Conclusion MDM increased detection sensitivity of P. falciparum-infected, haemozoin-containing erythrocytes from infected humans while maintaining detection of ring-stage parasites. Gametocyte prevalence five-fold higher than observed by CBS suggests higher malaria transmission potential in PNG endemic sites compared to previous estimates.

  16. Wavelet-based higher-order neural networks for mine detection in thermal IR imagery

    Science.gov (United States)

    Baertlein, Brian A.; Liao, Wen-Jiao

    2000-08-01

    An image processing technique is described for the detection of miens in RI imagery. The proposed technique is based on a third-order neural network, which processes the output of a wavelet packet transform. The technique is inherently invariant to changes in signature position, rotation and scaling. The well-known memory limitations that arise with higher-order neural networks are addressed by (1) the data compression capabilities of wavelet packets, (2) protections of the image data into a space of similar triangles, and (3) quantization of that 'triangle space'. Using these techniques, image chips of size 28 by 28, which would require 0(109) neural net weights, are processed by a network having 0(102) weights. ROC curves are presented for mine detection in real and simulated imagery.

  17. Increased Eating Frequency Is Associated with Lower Obesity Risk, But Higher Energy Intake in Adults: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Yue-Qiao Wang

    2016-06-01

    Full Text Available Body weight is regulated by energy intake which occurs several times a day in humans. In this meta-analysis, we evaluated whether eating frequency (EF is associated with obesity risk and energy intake in adults without any dietary restriction. Experimental and observational studies published before July 2015 were selected through English-language literature searches in several databases. These studies reported the association between EF and obesity risk (odd ratios, ORs in adults who were not in dietary restriction. R software was used to perform statistical analyses. Ten cross-sectional studies, consisting of 65,742 participants, were included in this analysis. ORs were considered as effect size for the analysis about the effect of EF on obesity risk. Results showed that the increase of EF was associated with 0.83 time lower odds of obesity (i.e., OR = 0.83, 95% confidence intervals (CI 0.70–0.99, p = 0.040. Analysis about the effect of EF on differences in participants’ energy intake revealed that increased EF was associated with higher energy intake (β = 125.36, 95% CI 21.76–228.97, p = 0.017. We conclude that increased EF may lead to lower obesity risk but higher energy intake. Clinical trials are warranted to confirm these results and to assess the clinical practice applicability.

  18. Odors pulsed at wing beat frequencies are tracked by primary olfactory networks and enhance odor detection

    Directory of Open Access Journals (Sweden)

    Shreejoy Tripathy

    2010-03-01

    Full Text Available Each down stroke of an insect’s wings accelerates axial airflow over the antennae. Modeling studies suggest that this can greatly enhance penetration of air and air-born odorants through the antennal sensilla thereby periodically increasing odorant-receptor interactions. Do these periodic changes result in entrainment of neural responses in the antenna and antennal lobe (AL? Does this entrainment affect olfactory acuity? To address these questions, we monitored antennal and AL responses in the moth Manduca sexta while odorants were pulsed at frequencies from 10-72 Hz, encompassing the natural wingbeat frequency. Power spectral density (PSD analysis was used to identify entrainment of neural activity. Statistical analysis of PSDs indicates that the antennal nerve tracked pulsed odor up to 30 Hz. Furthermore, at least 50% of AL local field potentials (LFPs and between 7-25% of unitary spiking responses also tracked pulsed odor up to 30 Hz in a frequency-locked manner. Application of bicuculline (200µM abolished pulse tracking in both LFP and unitary responses suggesting that GABAA receptor activation is necessary for pulse tracking within the AL. Finally, psychophysical measures of odor detection establish that detection thresholds are lowered when odor is pulsed at 20 Hz. These results suggest that AL networks can respond to the oscillatory dynamics of stimuli such as those imposed by the wing beat in a manner analogous to mammalian sniffing.

  19. Measurements of Low Frequency Noise of Infrared Photo-Detectors with Transimpedance Detection System

    Directory of Open Access Journals (Sweden)

    Ciura Łukasz

    2014-08-01

    Full Text Available The paper presents the method and results of low-frequency noise measurements of modern mid-wavelength infrared photodetectors. A type-II InAs/GaSb superlattice based detector with nBn barrier architecture is compared with a high operating temperature (HOT heterojunction HgCdTe detector. All experiments were made in the range 1 Hz - 10 kHz at various temperatures by using a transimpedance detection system, which is examined in detail. The power spectral density of the nBn’s dark current noise includes Lorentzians with different time constants while the HgCdTe photodiode has more uniform 1/f - shaped spectra. For small bias, the low-frequency noise power spectra of both devices were found to scale linearly with bias voltage squared and were connected with the fluctuations of the leakage resistance. Leakage resistance noise defines the lower noise limit of a photodetector. Other dark current components give raise to the increase of low-frequency noise above this limit. For the same voltage biasing devices, the absolute noise power densities at 1 Hz in nBn are 1 to 2 orders of magnitude lower than in a MCT HgCdTe detector. In spite of this, low-frequency performance of the HgCdTe detector at ~ 230K is still better than that of InAs/GaSb superlattice nBn detector.

  20. Hotspot detection using image pattern recognition based on higher-order local auto-correlation

    Science.gov (United States)

    Maeda, Shimon; Matsunawa, Tetsuaki; Ogawa, Ryuji; Ichikawa, Hirotaka; Takahata, Kazuhiro; Miyairi, Masahiro; Kotani, Toshiya; Nojima, Shigeki; Tanaka, Satoshi; Nakagawa, Kei; Saito, Tamaki; Mimotogi, Shoji; Inoue, Soichi; Nosato, Hirokazu; Sakanashi, Hidenori; Kobayashi, Takumi; Murakawa, Masahiro; Higuchi, Tetsuya; Takahashi, Eiichi; Otsu, Nobuyuki

    2011-04-01

    Below 40nm design node, systematic variation due to lithography must be taken into consideration during the early stage of design. So far, litho-aware design using lithography simulation models has been widely applied to assure that designs are printed on silicon without any error. However, the lithography simulation approach is very time consuming, and under time-to-market pressure, repetitive redesign by this approach may result in the missing of the market window. This paper proposes a fast hotspot detection support method by flexible and intelligent vision system image pattern recognition based on Higher-Order Local Autocorrelation. Our method learns the geometrical properties of the given design data without any defects as normal patterns, and automatically detects the design patterns with hotspots from the test data as abnormal patterns. The Higher-Order Local Autocorrelation method can extract features from the graphic image of design pattern, and computational cost of the extraction is constant regardless of the number of design pattern polygons. This approach can reduce turnaround time (TAT) dramatically only on 1CPU, compared with the conventional simulation-based approach, and by distributed processing, this has proven to deliver linear scalability with each additional CPU.

  1. Detection and Characterization of Flaws in Sprayed on Foam Insulation with Pulsed Terahertz Frequency Electromagnetic Waves

    Science.gov (United States)

    Winfree, William P.; Madaras, Eric I.

    2005-01-01

    The detection and repair of flaws such as voids and delaminations in the sprayed on foam insulation of the external tank reduces the probability of foam debris during shuttle ascent. The low density of sprayed on foam insulation along with it other physical properties makes detection of flaws difficult with conventional techniques. An emerging technology that has application for quantitative evaluation of flaws in the foam is pulsed electromagnetic waves at terahertz frequencies. The short wavelengths of these terahertz pulses make them ideal for imaging flaws in the foam. This paper examines the application of terahertz pulses for flaw detection in foam characteristic of the foam insulation of the external tank. Of particular interest is the detection of voids and delaminations, encapsulated in the foam or at the interface between the foam and a metal backing. The technique is shown to be capable of imaging small voids and delaminations through as much as 20 cm of foam. Methods for reducing the temporal responses of the terahertz pulses to improve flaw detection and yield quantitative characterizations of the size and location of the flaws are discussed.

  2. DynPeak: An Algorithm for Pulse Detection and Frequency Analysis in Hormonal Time Series

    Science.gov (United States)

    Vidal, Alexandre; Zhang, Qinghua; Médigue, Claire; Fabre, Stéphane; Clément, Frédérique

    2012-01-01

    The endocrine control of the reproductive function is often studied from the analysis of luteinizing hormone (LH) pulsatile secretion by the pituitary gland. Whereas measurements in the cavernous sinus cumulate anatomical and technical difficulties, LH levels can be easily assessed from jugular blood. However, plasma levels result from a convolution process due to clearance effects when LH enters the general circulation. Simultaneous measurements comparing LH levels in the cavernous sinus and jugular blood have revealed clear differences in the pulse shape, the amplitude and the baseline. Besides, experimental sampling occurs at a relatively low frequency (typically every 10 min) with respect to LH highest frequency release (one pulse per hour) and the resulting LH measurements are noised by both experimental and assay errors. As a result, the pattern of plasma LH may be not so clearly pulsatile. Yet, reliable information on the InterPulse Intervals (IPI) is a prerequisite to study precisely the steroid feedback exerted on the pituitary level. Hence, there is a real need for robust IPI detection algorithms. In this article, we present an algorithm for the monitoring of LH pulse frequency, basing ourselves both on the available endocrinological knowledge on LH pulse (shape and duration with respect to the frequency regime) and synthetic LH data generated by a simple model. We make use of synthetic data to make clear some basic notions underlying our algorithmic choices. We focus on explaining how the process of sampling affects drastically the original pattern of secretion, and especially the amplitude of the detectable pulses. We then describe the algorithm in details and perform it on different sets of both synthetic and experimental LH time series. We further comment on how to diagnose possible outliers from the series of IPIs which is the main output of the algorithm. PMID:22802933

  3. Overview of frequency bandwidth determination techniques of useful signal in case of leaks detection by correlation method

    International Nuclear Information System (INIS)

    Faerman, V A; Avramchuk, V S; Luneva, E E

    2014-01-01

    In this paper an overview of useful signal detection methods on the background of intense noise and limits determination methods of useful signal is presented. The following features are considered: peculiarities of usage of correlation analysis, cross-amplitude spectrum, coherence function, cross-phase spectrum, time-frequency correlation function in case of frequency limits determination as well as leaks detection in pipelines. The possibility of using time-frequency correlation function for solving above named issues is described. Time- frequency correlation function provides information about the signals correlation for each of the investigated frequency bands. Data about location of peaks on the surface plot of a time- frequency correlation function allows making an assumption about the spectral composition of useful signal and its frequency boundaries

  4. The Frequency Spectral Properties of Electrode-Skin Contact Impedance on Human Head and Its Frequency-Dependent Effects on Frequency-Difference EIT in Stroke Detection from 10Hz to 1MHz.

    Directory of Open Access Journals (Sweden)

    Lin Yang

    Full Text Available Frequency-difference electrical impedance tomography (fdEIT reconstructs frequency-dependent changes of a complex impedance distribution. It has a potential application in acute stroke detection because there are significant differences in impedance spectra between stroke lesions and normal brain tissues. However, fdEIT suffers from the influences of electrode-skin contact impedance since contact impedance varies greatly with frequency. When using fdEIT to detect stroke, it is critical to know the degree of measurement errors or image artifacts caused by contact impedance. To our knowledge, no study has systematically investigated the frequency spectral properties of electrode-skin contact impedance on human head and its frequency-dependent effects on fdEIT used in stroke detection within a wide frequency band (10 Hz-1 MHz. In this study, we first measured and analyzed the frequency spectral properties of electrode-skin contact impedance on 47 human subjects' heads within 10 Hz-1 MHz. Then, we quantified the frequency-dependent effects of contact impedance on fdEIT in stroke detection in terms of the current distribution beneath the electrodes and the contact impedance imbalance between two measuring electrodes. The results showed that the contact impedance at high frequencies (>100 kHz significantly changed the current distribution beneath the electrode, leading to nonnegligible errors in boundary voltages and artifacts in reconstructed images. The contact impedance imbalance at low frequencies (<1 kHz also caused significant measurement errors. We conclude that the contact impedance has critical frequency-dependent influences on fdEIT and further studies on reducing such influences are necessary to improve the application of fdEIT in stroke detection.

  5. The Frequency Spectral Properties of Electrode-Skin Contact Impedance on Human Head and Its Frequency-Dependent Effects on Frequency-Difference EIT in Stroke Detection from 10Hz to 1MHz.

    Science.gov (United States)

    Yang, Lin; Dai, Meng; Xu, Canhua; Zhang, Ge; Li, Weichen; Fu, Feng; Shi, Xuetao; Dong, Xiuzhen

    2017-01-01

    Frequency-difference electrical impedance tomography (fdEIT) reconstructs frequency-dependent changes of a complex impedance distribution. It has a potential application in acute stroke detection because there are significant differences in impedance spectra between stroke lesions and normal brain tissues. However, fdEIT suffers from the influences of electrode-skin contact impedance since contact impedance varies greatly with frequency. When using fdEIT to detect stroke, it is critical to know the degree of measurement errors or image artifacts caused by contact impedance. To our knowledge, no study has systematically investigated the frequency spectral properties of electrode-skin contact impedance on human head and its frequency-dependent effects on fdEIT used in stroke detection within a wide frequency band (10 Hz-1 MHz). In this study, we first measured and analyzed the frequency spectral properties of electrode-skin contact impedance on 47 human subjects' heads within 10 Hz-1 MHz. Then, we quantified the frequency-dependent effects of contact impedance on fdEIT in stroke detection in terms of the current distribution beneath the electrodes and the contact impedance imbalance between two measuring electrodes. The results showed that the contact impedance at high frequencies (>100 kHz) significantly changed the current distribution beneath the electrode, leading to nonnegligible errors in boundary voltages and artifacts in reconstructed images. The contact impedance imbalance at low frequencies (<1 kHz) also caused significant measurement errors. We conclude that the contact impedance has critical frequency-dependent influences on fdEIT and further studies on reducing such influences are necessary to improve the application of fdEIT in stroke detection.

  6. A Main Ring bunch length monitor by detecting two frequency components of the beam

    International Nuclear Information System (INIS)

    Ieiri, T.; Jackson, G.

    1989-01-01

    The bunch length is measured by detecting two revolution frequency harmonics of the beam and taking the ratio of their amplitudes. Two heterodyne receivers have been made to direct them, one at 53MHz and the other at 159MHz. These signals are picked-up by a stripline detector. An analog circuit provides a signal proportional to the bunch length. The monitor measures variation of the bunch length as a function of time in the Main Ring. The measured signal, which sometimes shows that the bunches are tumbling in phase space, can be damped by feedback to the RF amplitude modulator. 9 refs., 12 figs., 1 tab

  7. Electromagnetic characterization of superconducting radio-frequency cavities for gw detection

    Science.gov (United States)

    Ballantini, R.; Bernard, Ph; Chincarini, A.; Gemme, G.; Parodi, R.; Picasso, E.

    2004-03-01

    The electromagnetic properties of a prototype gravitational wave detector, based on two coupled superconducting microwave cavities, were tested. The radio-frequency (rf) detection system was carefully analysed. With the use of piezoelectric crystals small harmonic displacements of the cavity walls were induced and the parametric conversion of the electromagnetic field inside the cavities explored. Experimental results of bandwidth and sensitivity of the parametric converter versus stored energy and voltage applied to the piezoelectric crystal are reported. A rf control loop, developed to stabilize phase changes on signal paths, gave a 125 dBc rejection of the drive mode on a time scale of 1 h.

  8. Electromagnetic characterization of superconducting radio-frequency cavities for gw detection

    International Nuclear Information System (INIS)

    Ballantini, R; Bernard, Ph; Chincarini, A; Gemme, G; Parodi, R; Picasso, E

    2004-01-01

    The electromagnetic properties of a prototype gravitational wave detector, based on two coupled superconducting microwave cavities, were tested. The radio-frequency (rf) detection system was carefully analysed. With the use of piezoelectric crystals small harmonic displacements of the cavity walls were induced and the parametric conversion of the electromagnetic field inside the cavities explored. Experimental results of bandwidth and sensitivity of the parametric converter versus stored energy and voltage applied to the piezoelectric crystal are reported. A rf control loop, developed to stabilize phase changes on signal paths, gave a 125 dBc rejection of the drive mode on a time scale of 1 h

  9. Single Frequency Impedance Analysis on Reduced Graphene Oxide Screen-Printed Electrode for Biomolecular Detection.

    Science.gov (United States)

    Rajesh; Singal, Shobhita; Kotnala, Ravinder K

    2017-10-01

    A biofunctionalized reduced graphene oxide (rGO)-modified screen-printed carbon electrode (SPCE) was constructed as an immunosensor for C-reactive protein (CRP) detection, a biomarker released in early stage acute myocardial infarction. A different approach of single frequency analysis (SFA) study was utilized for the biomolecular sensing, by monitoring the response in phase angle changes obtained at an optimized frequency resulting from antigen-antibody interactions. A set of measurements were carried out to optimize a frequency where a maximum change in phase angle was observed, and in this case, we found it at around 10 Hz. The bioelectrode was characterized by contact angle measurements, scanning electron microscopy, and electrochemical techniques. A concentration-dependent response of immunosensor to CRP with the change in phase angle, at a fixed frequency of 10 Hz, was found to be in the range of 10 ng mL -1 to 10 μg mL -1 in PBS and was fit quantitative well with the Hill-Langmuir equation. Based on the concentration-response data, the dissociation constant (K d ) was found to be 3.5 nM (with a Hill coefficient n = 0.57), which indicated a negative cooperativity with high anti-CRP (antibody)-CRP (antigen) binding at the electrode surface. A low-frequency analysis of sensing with an ease of measurement on a disposable electroactive rGO-modified electrode with high selectivity and sensitivity makes it a potential tool for biological sensors.

  10. Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LAT

    International Nuclear Information System (INIS)

    Anderson, B.; Atwood, W.B.; Dormody, M.; Johnson, R.P.; Porter, T.A.; Primack, J.R.; Sadrozinski, H.F.W.; Parkinson, P.M.S.; Ziegler, M.; Abdo, A.A.; Dermer, C.D.; Grove, J.E.; Gwon, C.; Johnson, W.N.; Lovellette, M.N.; Makeev, A.; Ray, P.S.; Strickman, M.S.; Wolff, M.T.; Wood, K.S.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R.D.; Borgland, A.W.; Cameron, R.A.; Chiang, J.; Claus, R.; Digel, S.W.; Silva, E.D.E.; Drell, P.S.; Dubois, R.; Funk, S.; Glanzman, T.; Godfrey, G.; Hayashida, M.; Johannesson, G.; Kamae, T.; Kocian, M.L.; Lande, J.; Madejski, G.M.; Michelson, P.F.; Mitthumsiri, W.; Monzani, M.E.; Moskalenko, I.V.; Murgia, S.; Nolan, P.L.; Paneque, D.; Reimer, A.; Reimer, O.; Rochester, L.S.; Romani, R.W.; Tajima, H.; Tanaka, T.; Thayer, J.G.; Tramacere, A.; Uchiyama, Y.; Usher, T.L.; Van Etten, A.; Waite, A.P.; Wang, P.; Watters, K.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E.D.; Borgland, A.W.; Cameron, R.A.; Chiang, J.; Claus, R.; Digel, S.W.; Silva, E.D.E.; Drell, P.S.; Dubois, R.; Glanzman, T.; Godfrey, G.; Hayashida, M.; Johannesson, G.; Kamae, T.; Kocian, M.L.; Lande, J.; Madejski, G.M.; Michelson, P.F.; Mitthumsiri, W.; Monzani, M.E.; Moskalenko, I.V.; Murgia, S.; Nolan, P.L.; Paneque, D.; Reimer, A.; Reimer, O.; Rochester, L.S.; Romani, R.W.; Tajima, H.; Tanaka, T.; Thayer, J.G.; Tramacere, A.; Uchiyama, Y.; Usher, T.L.; Van Etten, A.; Waite, A.P.; Wang, P.; Watters, K.; Axelsson, M.; Conrad, J.; Meurer, C.; Ryde, F.; Ylinen, T.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Kuss, M.; Latronico, L.; Omodei, N.; Pesce-Rollins, M.; Razzano, M.; Sgro, C.; Spandre, G.; Ballet, J.; Casandjian, J.M.; Grenier, I.A.; Pierbattista, M.; Starck, J.L.

    2009-01-01

    Pulsars are rapidly rotating, highly magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there are more than 1800 known radio pulsars, until recently only seven were observed to pulse in gamma rays, and these were all discovered at other wavelengths. The Fermi Large Area Telescope (LAT) makes it possible to pinpoint neutron stars through their gamma-ray pulsations. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants. Direct detection of gamma-ray pulsars enables studies of emission mechanisms, population statistics, and the energetics of pulsar wind nebulae and supernova remnants. (authors)

  11. Detecting chaos in particle accelerators through the frequency map analysis method.

    Science.gov (United States)

    Papaphilippou, Yannis

    2014-06-01

    The motion of beams in particle accelerators is dominated by a plethora of non-linear effects, which can enhance chaotic motion and limit their performance. The application of advanced non-linear dynamics methods for detecting and correcting these effects and thereby increasing the region of beam stability plays an essential role during the accelerator design phase but also their operation. After describing the nature of non-linear effects and their impact on performance parameters of different particle accelerator categories, the theory of non-linear particle motion is outlined. The recent developments on the methods employed for the analysis of chaotic beam motion are detailed. In particular, the ability of the frequency map analysis method to detect chaotic motion and guide the correction of non-linear effects is demonstrated in particle tracking simulations but also experimental data.

  12. High-Throughput, Protein-Targeted Biomolecular Detection Using Frequency-Domain Faraday Rotation Spectroscopy.

    Science.gov (United States)

    Murdock, Richard J; Putnam, Shawn A; Das, Soumen; Gupta, Ankur; Chase, Elyse D Z; Seal, Sudipta

    2017-03-01

    A clinically relevant magneto-optical technique (fd-FRS, frequency-domain Faraday rotation spectroscopy) for characterizing proteins using antibody-functionalized magnetic nanoparticles (MNPs) is demonstrated. This technique distinguishes between the Faraday rotation of the solvent, iron oxide core, and functionalization layers of polyethylene glycol polymers (spacer) and model antibody-antigen complexes (anti-BSA/BSA, bovine serum albumin). A detection sensitivity of ≈10 pg mL -1 and broad detection range of 10 pg mL -1 ≲ c BSA ≲ 100 µg mL -1 are observed. Combining this technique with predictive analyte binding models quantifies (within an order of magnitude) the number of active binding sites on functionalized MNPs. Comparative enzyme-linked immunosorbent assay (ELISA) studies are conducted, reproducing the manufacturer advertised BSA ELISA detection limits from 1 ng mL -1 ≲ c BSA ≲ 500 ng mL -1 . In addition to the increased sensitivity, broader detection range, and similar specificity, fd-FRS can be conducted in less than ≈30 min, compared to ≈4 h with ELISA. Thus, fd-FRS is shown to be a sensitive optical technique with potential to become an efficient diagnostic in the chemical and biomolecular sciences. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Non-Linear Detection for Joint Space-Frequency Block Coding and Spatial Multiplexing in OFDM-MIMO Systems

    DEFF Research Database (Denmark)

    Rahman, Imadur Mohamed; Marchetti, Nicola; Fitzek, Frank

    2005-01-01

    (SIC) receiver where the detection is done on subcarrier by sub-carrier basis based on both Zero Forcing (ZF) and Minimum Mean Square Error (MMSE) nulling criterion for the system. In terms of Frame Error Rate (FER), MMSE based SIC receiver performs better than all other receivers compared......In this work, we have analyzed a joint spatial diversity and multiplexing transmission structure for MIMO-OFDM system, where Orthogonal Space-Frequency Block Coding (OSFBC) is used across all spatial multiplexing branches. We have derived a BLAST-like non-linear Successive Interference Cancellation...... in this paper. We have found that a linear two-stage receiver for the proposed system [1] performs very close to the non-linear receiver studied in this work. Finally, we compared the system performance in spatially correlated scenario. It is found that higher amount of spatial correlation at the transmitter...

  14. Masking of Time-Frequency Patterns in Applications of Passive Underwater Target Detection

    Directory of Open Access Journals (Sweden)

    Jüri Sildam

    2010-01-01

    Full Text Available Spectrogram analysis of acoustical sounds for underwater target classification is utilized when loud nonstationary interference sources overlap with a signal of interest in time but can be separated in time-frequency (TF domain. We propose a signal masking method which in a TF plane combines local statistical and morphological features of the signal of interest. A dissimilarity measure D of adjacent TF cells is used for local estimation of entropy H, followed by estimation of ΔH=Htc−Hfc entropy difference, where Hfc is calculated along the time axis at a mean frequency fc and Htc is calculated along the frequency axis at a mean time tc of the TF window, respectively. Due to a limited number of points used in ΔH estimation, the number of possible ΔH values, which define a primary mask, is also limited. A secondary mask is defined using morphological operators applied to, for example, H and ΔH. We demonstrate how primary and secondary masks can be used for signal detection and discrimination, respectively. We also show that the proposed approach can be generalized within the framework of Genetic Programming.

  15. Balanced homodyne detection of optical quantum states at audio-band frequencies and below

    International Nuclear Information System (INIS)

    Stefszky, M S; Mow-Lowry, C M; Chua, S S Y; Shaddock, D A; Buchler, B C; Lam, P K; McClelland, D E; Vahlbruch, H; Khalaidovski, A; Schnabel, R

    2012-01-01

    The advent of stable, highly squeezed states of light has generated great interest in the gravitational wave community as a means for improving the quantum-noise-limited performance of advanced interferometric detectors. To confidently measure these squeezed states, it is first necessary to measure the shot-noise across the frequency band of interest. Technical noise, such as non-stationary events, beam pointing, and parasitic interference, can corrupt shot-noise measurements at low Fourier frequencies, below tens of kilo-hertz. In this paper we present a qualitative investigation into all of the relevant noise sources and the methods by which they can be identified and mitigated in order to achieve quantum noise limited balanced homodyne detection. Using these techniques, flat shot-noise down to Fourier frequencies below 0.5 Hz is produced. This enables the direct observation of large magnitudes of squeezing across the entire audio-band, of particular interest for ground-based interferometric gravitational wave detectors. 11.6 dB of shot-noise suppression is directly observed, with more than 10 dB down to 10 Hz. (paper)

  16. Resonant Frequency Calculation and Optimal Design of Peano Fractal Antenna for Partial Discharge Detection

    Directory of Open Access Journals (Sweden)

    Jian Li

    2012-01-01

    Full Text Available Ultra-high-frequency (UHF approaches have caught increasing attention recently and have been considered as a promising technology for online monitoring partial discharge (PD signals. This paper presents a Peano fractal antenna for UHF PD online monitoring of transformer with small size and multiband. The approximate formula for calculating the first resonant frequency of the Peano fractal antenna is presented. The results show that the first resonant frequency of the Peano fractal antenna is smaller than the Hilbert fractal antenna when the outer dimensions are equivalent approximately. The optimal geometric parameters of the antenna were obtained through simulation. Actual PD experiments had been carried out for two typically artificial insulation defect models, while the proposed antenna and the existing Hilbert antenna were both used for the PD measurement. The experimental results show that Peano fractal antenna is qualified for PD online UHF monitoring and a little more suitable than the Hilbert fractal antenna for pattern recognition by analyzing the waveforms of detected UHF PD signals.

  17. High-Frequency X-ray Variability Detection in A Black Hole Transient with USA.

    Energy Technology Data Exchange (ETDEWEB)

    Shabad, Gayane

    2000-10-16

    Studies of high-frequency variability (above {approx}100 Hz) in X-ray binaries provide a unique opportunity to explore the fundamental physics of spacetime and matter, since the orbital timescale on the order of several milliseconds is a timescale of the motion of matter through the region located in close proximity to a compact stellar object. The detection of weak high-frequency signals in X-ray binaries depends on how well we understand the level of Poisson noise due to the photon counting statistics, i.e. how well we can understand and model the detector deadtime and other instrumental systematic effects. We describe the preflight timing calibration work performed on the Unconventional Stellar Aspect (USA) X-ray detector to study deadtime and timing issues. We developed a Monte Carlo deadtime model and deadtime correction methods for the USA experiment. The instrumental noise power spectrum can be estimated within {approx}0.1% accuracy in the case when no energy-dependent instrumental effect is present. We also developed correction techniques to account for an energy-dependent instrumental effect. The developed methods were successfully tested on USA Cas A and Cygnus X-1 data. This work allowed us to make a detection of a weak signal in a black hole candidate (BHC) transient.

  18. Quantitative Surface Chirality Detection with Sum Frequency Generation Vibrational Spectroscopy: Twin Polarization Angle Approach

    International Nuclear Information System (INIS)

    Wei, Feng; Xu, Yanyan; Guo, Yuan; Liu, Shi-lin; Wang, Hongfei

    2009-01-01

    Here we report a novel twin polarization angle (TPA) approach in the quantitative chirality detection with the surface sum-frequency generation vibrational spectroscopy (SFG-VS). Generally, the achiral contribution dominates the surface SFG-VS signal, and the pure chiral signal is usually two or three orders of magnitude smaller. Therefore, it has been difficult to make quantitative detection and analysis of the chiral contributions to the surface SFG-VS signal. In the TPA method, by varying together the polarization angles of the incoming visible light and the sum frequency signal at fixed s or p polarization of the incoming infrared beam, the polarization dependent SFG signal can give not only direct signature of the chiral contribution in the total SFG-VS signal, but also the accurate measurement of the chiral and achiral components in the surface SFG signal. The general description of the TPA method is presented and the experiment test of the TPA approach is also presented for the SFG-VS from the S- and R-limonene chiral liquid surfaces. The most accurate degree of chiral excess values thus obtained for the 2878 cm -1 spectral peak of the S- and R-limonene liquid surfaces are (23.7±0.4)% and (25.4±1.3)%, respectively.

  19. On-line low and high frequency acoustic leak detection and location for an automated steam generator protection system

    International Nuclear Information System (INIS)

    Gaubatz, D.C.; Gluekler, E.L.

    1990-01-01

    Two on-line acoustic leak detection systems were operated and installed on a 76 MW hockey stick steam generator in the Sodium Components Test Installation (SCTI) at the Energy Technology Engineering Center (ETEC) in Southern California. The low frequency system demonstrated the capability to detect and locate leaks, both intentional and unintentional. No false alarms were issued during the two year test program even with adjacent blasting activities, pneumatic drilling, shuttle rocket engine testing nearby, scrams of the SCTI facility, thermal/hydraulic transient testing, and pump/control valve operations. For the high frequency system the capability to detect water into sodium reactions was established utilizing frequencies as high as 300 kHz. The high frequency system appeared to be sensitive to noise generated by maintenance work and system valve operations. Subsequent development work which is incomplete as of this date showed much more promise for the high frequency system. (author). 13 figs

  20. Automated Bayesian model development for frequency detection in biological time series

    Directory of Open Access Journals (Sweden)

    Oldroyd Giles ED

    2011-06-01

    Full Text Available Abstract Background A first step in building a mathematical model of a biological system is often the analysis of the temporal behaviour of key quantities. Mathematical relationships between the time and frequency domain, such as Fourier Transforms and wavelets, are commonly used to extract information about the underlying signal from a given time series. This one-to-one mapping from time points to frequencies inherently assumes that both domains contain the complete knowledge of the system. However, for truncated, noisy time series with background trends this unique mapping breaks down and the question reduces to an inference problem of identifying the most probable frequencies. Results In this paper we build on the method of Bayesian Spectrum Analysis and demonstrate its advantages over conventional methods by applying it to a number of test cases, including two types of biological time series. Firstly, oscillations of calcium in plant root cells in response to microbial symbionts are non-stationary and noisy, posing challenges to data analysis. Secondly, circadian rhythms in gene expression measured over only two cycles highlights the problem of time series with limited length. The results show that the Bayesian frequency detection approach can provide useful results in specific areas where Fourier analysis can be uninformative or misleading. We demonstrate further benefits of the Bayesian approach for time series analysis, such as direct comparison of different hypotheses, inherent estimation of noise levels and parameter precision, and a flexible framework for modelling the data without pre-processing. Conclusions Modelling in systems biology often builds on the study of time-dependent phenomena. Fourier Transforms are a convenient tool for analysing the frequency domain of time series. However, there are well-known limitations of this method, such as the introduction of spurious frequencies when handling short and noisy time series, and

  1. Automated Bayesian model development for frequency detection in biological time series.

    Science.gov (United States)

    Granqvist, Emma; Oldroyd, Giles E D; Morris, Richard J

    2011-06-24

    A first step in building a mathematical model of a biological system is often the analysis of the temporal behaviour of key quantities. Mathematical relationships between the time and frequency domain, such as Fourier Transforms and wavelets, are commonly used to extract information about the underlying signal from a given time series. This one-to-one mapping from time points to frequencies inherently assumes that both domains contain the complete knowledge of the system. However, for truncated, noisy time series with background trends this unique mapping breaks down and the question reduces to an inference problem of identifying the most probable frequencies. In this paper we build on the method of Bayesian Spectrum Analysis and demonstrate its advantages over conventional methods by applying it to a number of test cases, including two types of biological time series. Firstly, oscillations of calcium in plant root cells in response to microbial symbionts are non-stationary and noisy, posing challenges to data analysis. Secondly, circadian rhythms in gene expression measured over only two cycles highlights the problem of time series with limited length. The results show that the Bayesian frequency detection approach can provide useful results in specific areas where Fourier analysis can be uninformative or misleading. We demonstrate further benefits of the Bayesian approach for time series analysis, such as direct comparison of different hypotheses, inherent estimation of noise levels and parameter precision, and a flexible framework for modelling the data without pre-processing. Modelling in systems biology often builds on the study of time-dependent phenomena. Fourier Transforms are a convenient tool for analysing the frequency domain of time series. However, there are well-known limitations of this method, such as the introduction of spurious frequencies when handling short and noisy time series, and the requirement for uniformly sampled data. Biological time

  2. The Effect of an Added Mass on the Frequency Shifts of a Clamped-Clamped Microbeam for Bio-Mass Detection

    KAUST Repository

    Bouchaala, Adam M.; Nayfeh, Ali H.; Younis, Mohammad I.

    2016-01-01

    We present analytical formulations to calculate the induced resonance frequency shifts of electrically actuated clamped-clamped microbeams due to an added mass. Based on the Euler-Bernoulli beam theory, we investigate the linear dynamic responses of the beams added masses, which are modeled as discrete point masses. Analytical expressions based on perturbation techniques and a one-mode Galerkin approximation are developed to calculate accurately the frequency shifts under a DC voltage as a function of the added mass and position. The analytical results are compared to numerical solution of the eigenvalue problem. Results are shown for the fundamental as well as the higher-order modes of the beams. The results indicate a significant increase in the frequency shift, and hence the sensitivity of detection, when scaling down to nano scale and using higher-order modes.

  3. The Effect of an Added Mass on the Frequency Shifts of a Clamped-Clamped Microbeam for Bio-Mass Detection

    KAUST Repository

    Bouchaala, Adam M.

    2016-12-05

    We present analytical formulations to calculate the induced resonance frequency shifts of electrically actuated clamped-clamped microbeams due to an added mass. Based on the Euler-Bernoulli beam theory, we investigate the linear dynamic responses of the beams added masses, which are modeled as discrete point masses. Analytical expressions based on perturbation techniques and a one-mode Galerkin approximation are developed to calculate accurately the frequency shifts under a DC voltage as a function of the added mass and position. The analytical results are compared to numerical solution of the eigenvalue problem. Results are shown for the fundamental as well as the higher-order modes of the beams. The results indicate a significant increase in the frequency shift, and hence the sensitivity of detection, when scaling down to nano scale and using higher-order modes.

  4. Consumption Frequency of Foods Away from Home Linked with Higher Body Mass Index and Lower Fruit and Vegetable Intake among Adults: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Rebecca A. Seguin

    2016-01-01

    Full Text Available Introduction. Consumption of foods prepared away from home (FAFH has grown steadily since the 1970s. We examined the relationship between FAFH and body mass index (BMI and fruit and vegetable (FV consumption. Methods. Frequency of FAFH, daily FV intake, height and weight, and sociodemographic data were collected using a telephone survey in 2008-2009. Participants included a representative sample of 2,001 adult men and women (mean age 54±15 years residing in King County, WA, with an analytical sample of 1,570. Frequency of FAFH was categorized as 0-1, 2–4, or 5+ times per week. BMI was calculated from self-reported height and weight. We examined the relationship between FAFH with FV consumption and BMI using multivariate models. Results. Higher frequency of FAFH was associated with higher BMI, after adjusting for age, income, education, race, smoking, marital status, and physical activity (women: p=0.001; men: p=0.003. There was a negative association between frequency of FAFH and FV consumption. FAFH frequency was significantly (p<0.001 higher among males than females (43.1% versus 54.0% eating out 0-1 meal per week, resp.. Females reported eating significantly (p<0.001 more FV than males. Conclusion. Among adults, higher frequency of FAFH was related to higher BMI and less FV consumption.

  5. Consumption Frequency of Foods Away from Home Linked with Higher Body Mass Index and Lower Fruit and Vegetable Intake among Adults: A Cross-Sectional Study

    Science.gov (United States)

    Seguin, Rebecca A.; Aggarwal, Anju; Vermeylen, Francoise; Drewnowski, Adam

    2016-01-01

    Introduction. Consumption of foods prepared away from home (FAFH) has grown steadily since the 1970s. We examined the relationship between FAFH and body mass index (BMI) and fruit and vegetable (FV) consumption. Methods. Frequency of FAFH, daily FV intake, height and weight, and sociodemographic data were collected using a telephone survey in 2008-2009. Participants included a representative sample of 2,001 adult men and women (mean age 54 ± 15 years) residing in King County, WA, with an analytical sample of 1,570. Frequency of FAFH was categorized as 0-1, 2–4, or 5+ times per week. BMI was calculated from self-reported height and weight. We examined the relationship between FAFH with FV consumption and BMI using multivariate models. Results. Higher frequency of FAFH was associated with higher BMI, after adjusting for age, income, education, race, smoking, marital status, and physical activity (women: p = 0.001; men: p = 0.003). There was a negative association between frequency of FAFH and FV consumption. FAFH frequency was significantly (p < 0.001) higher among males than females (43.1% versus 54.0% eating out 0-1 meal per week, resp.). Females reported eating significantly (p < 0.001) more FV than males. Conclusion. Among adults, higher frequency of FAFH was related to higher BMI and less FV consumption. PMID:26925111

  6. Recent sediment dynamics in hadal trenches: Evidence for the influence of higher-frequency (tidal, near-inertial) fluid dynamics

    Science.gov (United States)

    Turnewitsch, Robert; Falahat, Saeed; Stehlikova, Jirina; Oguri, Kazumasa; Glud, Ronnie N.; Middelboe, Mathias; Kitazato, Hiroshi; Wenzhöfer, Frank; Ando, Kojiro; Fujio, Shinzou; Yanagimoto, Daigo

    2014-08-01

    In addition to high hydrostatic pressure, scarcity of food is viewed as a factor that limits the abundance and activity of heterotrophic organisms at great ocean depths, including hadal trenches. Supply of nutritious food largely relies on the flux of organic-rich particulate matter from the surface ocean. It has been speculated that the shape of hadal trenches helps to ‘funnel' particulate matter into the deeper parts of the trench, leading to sediment ‘focussing' and improved benthic food supply. Here we investigate for five Northwest Pacific trenches the efficiency of sediment focussing by evaluating ratios of measured (sediment-derived) and expected (water-column-derived) sedimentary inventories of the naturally occurring and radioactive particulate-matter tracer 210Pbxs. The sites comprise a broad range of surface-ocean productivity and physical-oceanographic regimes. Across the five trench-axis settings the inventory ratio varies between 0.5 and 4.1, with four trench-axis settings having ratios>1 (sediment focussing) and one trench-axis setting a ratiowinnowing). Although the fluid- and sediment-dynamical forcing behind sediment focussing remains unclear, this study finds evidence for another mechanism that is superimposed on, and counteracts, the focussing mechanism. This superimposed mechanism is related to higher-frequency (tidal, near-inertial) fluid dynamics. In particular, there is evidence for a strong and negative relation between the intensity of propagating internal tides and the extent of sediment focussing in the trench-axis. The relation can be approximated by a power function and the most intense drop in sediment focussing already occurs at moderate internal-tide intensities. This suggests that propagating internal tides may have a subtle but significant influence on particulate-matter dynamics and food supply in hadal trenches in particular, but possibly also in the deep seas in general. A mechanism for the influence of internal tides on

  7. Detection and classification of defects in ultrasonic NDE signals using time-frequency representations

    Science.gov (United States)

    Qidwai, Uvais; Costa, Antonio H.; Chen, C. H.

    2000-05-01

    The ultrasonic wave, generated by a piezoelectric transducer coupled to the test specimen, propagates through the material and part of its energy is reflected when it encounters an non-homogeneity or discontinuity in its path, while the remainder is reflected by the back surface of the test specimen. Defect echo signals are masked by the characteristics of the measuring instruments, the propagation paths taken by the ultrasonic wave, and are corrupted by additive noise. This leads to difficulties in comparing and analyzing signals, particularly in automated defect identification systems employing different transducers. Further, the multi-component nature of material defects can add to the complexity of the defect identification criteria. With many one-dimensional (1-D) approaches, the multi-component defects can not be detected. Another drawback is that these techniques are not very robust for sharp ultrasonic peaks especially in a very hazardous environment. This paper proposes a technique based on the time-frequency representations (TFRs) of the real defect signals corresponding to artificially produced defects of various geometries in metals. Cohen's class (quadratic) TFRs with Gaussian kernels are then used to represent the signals in the time-frequency (TF) plane. Once the TFR is obtained, various image processing morphological techniques are applied to the TFR (e.g. region of interest masking, edge detection, and profile separation). Based on the results of these operations, a binary image is produced which, in turn, leads to a novel set of features. Using these new features, defects have not only been detected but also classified as flat-cut, angular-cut, and circular-drills. Moreover, with some modifications of the threshold levels of the TFR kernel design, our technique can be used in relatively hostile environments with SNRs as low as 0 dB. Another important characteristic of our approach is the detection of multiple defects. This consists of detection of

  8. Multichannel interictal spike activity detection using time-frequency entropy measure.

    Science.gov (United States)

    Thanaraj, Palani; Parvathavarthini, B

    2017-06-01

    Localization of interictal spikes is an important clinical step in the pre-surgical assessment of pharmacoresistant epileptic patients. The manual selection of interictal spike periods is cumbersome and involves a considerable amount of analysis workload for the physician. The primary focus of this paper is to automate the detection of interictal spikes for clinical applications in epilepsy localization. The epilepsy localization procedure involves detection of spikes in a multichannel EEG epoch. Therefore, a multichannel Time-Frequency (T-F) entropy measure is proposed to extract features related to the interictal spike activity. Least squares support vector machine is used to train the proposed feature to classify the EEG epochs as either normal or interictal spike period. The proposed T-F entropy measure, when validated with epilepsy dataset of 15 patients, shows an interictal spike classification accuracy of 91.20%, sensitivity of 100% and specificity of 84.23%. Moreover, the area under the curve of Receiver Operating Characteristics plot of 0.9339 shows the superior classification performance of the proposed T-F entropy measure. The results of this paper show a good spike detection accuracy without any prior information about the spike morphology.

  9. High temperature radio-frequency superconducting quantum interference device system for detection of magnetic nanoparticles

    International Nuclear Information System (INIS)

    Pretzell, Alf

    2012-01-01

    This doctoral thesis was aimed at establishing a set-up with high-temperature superconductor (HTS) radio-frequency (rf) superconducting quantum interference device (SQUID) technology for the detection of magnetic nanoparticles and in particular for testing applications of magnetic nanoparticle immunoassays. It was part of the EU-project ''Biodiagnostics'' running from 2005 to 2008. The method of magnetic binding assays was developed as an alternative to other methods of concentration determination like enzyme linked immunosorbent assay (ELISA), or fluorescent immunoassay. The ELISA has sensitivities down to analyte-concentrations of pg/ml. Multiple incubation and washing steps have to be performed for these techniques, the analyte has to diffuse to the site of binding. The magnetic assay uses magnetic nanoparticles as markers for the substance to be detected. It is being explored by current research and shows similar sensitivity compared to ELISA but in contrast - does not need any washing and can be read out directly after binding - can be applied in solution with opaque media, e.g. blood or muddy water - additionally allows magnetic separation or concentration - in combination with small magnetoresistive or Hall sensors, allows detection of only a few particles or even single beads. For medical or environmental samples, maybe opaque and containing a multitude of substances, it would be advantageous to devise an instrument, which allows to be read out quickly and with high sensitivity. Due to the mentioned items the magnetic assay might be a possibility here.

  10. Study of cumulative fatigue damage detection for used parts with nonlinear output frequency response functions based on NARMAX modelling

    Science.gov (United States)

    Huang, Honglan; Mao, Hanying; Mao, Hanling; Zheng, Weixue; Huang, Zhenfeng; Li, Xinxin; Wang, Xianghong

    2017-12-01

    Cumulative fatigue damage detection for used parts plays a key role in the process of remanufacturing engineering and is related to the service safety of the remanufactured parts. In light of the nonlinear properties of used parts caused by cumulative fatigue damage, the based nonlinear output frequency response functions detection approach offers a breakthrough to solve this key problem. First, a modified PSO-adaptive lasso algorithm is introduced to improve the accuracy of the NARMAX model under impulse hammer excitation, and then, an effective new algorithm is derived to estimate the nonlinear output frequency response functions under rectangular pulse excitation, and a based nonlinear output frequency response functions index is introduced to detect the cumulative fatigue damage in used parts. Then, a novel damage detection approach that integrates the NARMAX model and the rectangular pulse is proposed for nonlinear output frequency response functions identification and cumulative fatigue damage detection of used parts. Finally, experimental studies of fatigued plate specimens and used connecting rod parts are conducted to verify the validity of the novel approach. The obtained results reveal that the new approach can detect cumulative fatigue damages of used parts effectively and efficiently and that the various values of the based nonlinear output frequency response functions index can be used to detect the different fatigue damages or working time. Since the proposed new approach can extract nonlinear properties of systems by only a single excitation of the inspected system, it shows great promise for use in remanufacturing engineering applications.

  11. Combining Frequency Doubling Technology Perimetry and Scanning Laser Polarimetry for Glaucoma Detection.

    Science.gov (United States)

    Mwanza, Jean-Claude; Warren, Joshua L; Hochberg, Jessica T; Budenz, Donald L; Chang, Robert T; Ramulu, Pradeep Y

    2015-01-01

    To determine the ability of frequency doubling technology (FDT) and scanning laser polarimetry with variable corneal compensation (GDx-VCC) to detect glaucoma when used individually and in combination. One hundred ten normal and 114 glaucomatous subjects were tested with FDT C-20-5 screening protocol and the GDx-VCC. The discriminating ability was tested for each device individually and for both devices combined using GDx-NFI, GDx-TSNIT, number of missed points of FDT, and normal or abnormal FDT. Measures of discrimination included sensitivity, specificity, area under the curve (AUC), Akaike's information criterion (AIC), and prediction confidence interval lengths. For detecting glaucoma regardless of severity, the multivariable model resulting from the combination of GDx-TSNIT, number of abnormal points on FDT (NAP-FDT), and the interaction GDx-TSNIT×NAP-FDT (AIC: 88.28, AUC: 0.959, sensitivity: 94.6%, specificity: 89.5%) outperformed the best single-variable model provided by GDx-NFI (AIC: 120.88, AUC: 0.914, sensitivity: 87.8%, specificity: 84.2%). The multivariable model combining GDx-TSNIT, NAP-FDT, and interaction GDx-TSNIT×NAP-FDT consistently provided better discriminating abilities for detecting early, moderate, and severe glaucoma than the best single-variable models. The multivariable model including GDx-TSNIT, NAP-FDT, and the interaction GDx-TSNIT×NAP-FDT provides the best glaucoma prediction compared with all other multivariable and univariable models. Combining the FDT C-20-5 screening protocol and GDx-VCC improves glaucoma detection compared with using GDx or FDT alone.

  12. Mach-Zehnder interferometric photonic crystal fiber for low acoustic frequency detections

    Energy Technology Data Exchange (ETDEWEB)

    Pawar, Dnyandeo; Rao, Ch. N.; Kale, S. N., E-mail: sangeetakale2004@gmail.com [Department of Applied Physics, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411 025, Maharashtra (India); Choubey, Ravi Kant [Department of Applied Physics, Amity Institute of Applied Sciences, Amity University, Noida 201 313 (India)

    2016-01-25

    Low frequency under-water acoustic signal detections are challenging, especially for marine applications. A Mach-Zehnder interferometric hydrophone is demonstrated using polarization-maintaining photonic-crystal-fiber (PM-PCF), spliced between two single-mode-fibers, operated at 1550 nm source. These data are compared with standard hydrophone, single-mode and multimode fiber. The PM-PCF sensor shows the highest response with a power shift (2.32 dBm) and a wavelength shift (392.8 pm) at 200 Hz. High birefringence values and the effect of the imparted acoustic pressure on this fiber, introducing the difference between the fast and slow axis changes, owing to the phase change in the propagation waves, demonstrate the strain-optic properties of the sensor.

  13. Hotspots ampersand other hidden targets: Probability of detection, number, frequency and area

    International Nuclear Information System (INIS)

    Vita, C.L.

    1994-01-01

    Concepts and equations are presented for making probability-based estimates of the detection probability, and the number, frequency, and area of hidden targets, including hotspots, at a given site. Targets include hotspots, which are areas of extreme or particular contamination, and any object or feature that is hidden from direct visual observation--including buried objects and geologic or hydrologic details or anomalies. Being Bayesian, results are fundamentally consistent with observational methods. Results are tools for planning or interpreting exploration programs used in site investigation or characterization, remedial design, construction, or compliance monitoring, including site closure. Used skillfully and creatively, these tools can help streamline and expedite environmental restoration, reducing time and cost, making site exploration cost-effective, and providing acceptable risk at minimum cost. 14 refs., 4 figs

  14. Enhanced detection of a low-frequency signal by using broad squeezed light and a bichromatic local oscillator

    Science.gov (United States)

    Li, Wei; Jin, Yuanbin; Yu, Xudong; Zhang, Jing

    2017-08-01

    We experimentally study a protocol of using the broadband high-frequency squeezed vacuum to detect the low-frequency signal. In this scheme, the lower sideband field of the squeezed light carries the low-frequency modulation signal, and the two strong coherent light fields are applied as the bichromatic local oscillator in the homodyne detection to measure the quantum entanglement of the upper and lower sideband for the broadband squeezed light. The power of one of the local oscillators for detecting the upper sideband can be adjusted to optimize the conditional variance in the low-frequency regime by subtracting the photocurrent of the upper sideband field of the squeezed light from that of the lower sideband field. By means of the quantum correlation of the upper and lower sideband for the broadband squeezed light, the low-frequency signal beyond the standard quantum limit is measured. This scheme is appropriate for enhancing the sensitivity of the low-frequency signal by the aid of the broad squeezed light, such as gravitational waves detection, and does not need to directly produce the low-frequency squeezing in an optical parametric process.

  15. Modeling the frequency-dependent detective quantum efficiency of photon-counting x-ray detectors.

    Science.gov (United States)

    Stierstorfer, Karl

    2018-01-01

    To find a simple model for the frequency-dependent detective quantum efficiency (DQE) of photon-counting detectors in the low flux limit. Formula for the spatial cross-talk, the noise power spectrum and the DQE of a photon-counting detector working at a given threshold are derived. Parameters are probabilities for types of events like single counts in the central pixel, double counts in the central pixel and a neighboring pixel or single count in a neighboring pixel only. These probabilities can be derived in a simple model by extensive use of Monte Carlo techniques: The Monte Carlo x-ray propagation program MOCASSIM is used to simulate the energy deposition from the x-rays in the detector material. A simple charge cloud model using Gaussian clouds of fixed width is used for the propagation of the electric charge generated by the primary interactions. Both stages are combined in a Monte Carlo simulation randomizing the location of impact which finally produces the required probabilities. The parameters of the charge cloud model are fitted to the spectral response to a polychromatic spectrum measured with our prototype detector. Based on the Monte Carlo model, the DQE of photon-counting detectors as a function of spatial frequency is calculated for various pixel sizes, photon energies, and thresholds. The frequency-dependent DQE of a photon-counting detector in the low flux limit can be described with an equation containing only a small set of probabilities as input. Estimates for the probabilities can be derived from a simple model of the detector physics. © 2017 American Association of Physicists in Medicine.

  16. Dual fiber Bragg gratings configuration-based fiber acoustic sensor for low-frequency signal detection

    Science.gov (United States)

    Yang, Dong; Wang, Shun; Lu, Ping; Liu, Deming

    2014-11-01

    We propose and fabricate a new type fiber acoustic sensor based on dual fiber Bragg gratings (FBGs) configuration. The acoustic sensor head is constructed by putting the sensing cells enclosed in an aluminum cylinder space built by two Cband FBGs and a titanium diaphragm of 50 um thickness. One end of each FBG is longitudinally adhered to the diaphragm by UV glue. Both of the two FBGs are employed for reflecting light. The dual FBGs play roles not only as signal transmission system but also as sensing component, and they demodulate each other's optical signal mutually during the measurement. Both of the two FBGs are pre-strained and the output optical power experiences fluctuation in a linear relationship along with a variation of axial strain and surrounding acoustic interference. So a precise approach to measure the frequency and sound pressure of the acoustic disturbance is achieved. Experiments are performed and results show that a relatively flat frequency response in a range from 200 Hz to 1 kHz with the average signal-to-noise ratio (SNR) above 21 dB is obtained. The maximum sound pressure sensitivity of 11.35mV/Pa is achieved with the Rsquared value of 0.99131 when the sound pressure in the range of 87.7-106.6dB. It has potential applications in low frequency signal detection. Owing to its direct self-demodulation method, the sensing system reveals the advantages of easy to demodulate, good temperature stability and measurement reliability. Besides, performance of the proposed sensor could be improved by optimizing the parameters of the sensor, especially the diaphragm.

  17. Building Quakes: Detection of Weld Fractures in Buildings using High-Frequency Seismic Techniques

    Science.gov (United States)

    Heckman, V.; Kohler, M. D.; Heaton, T. H.

    2009-12-01

    Catastrophic fracture of welded beam-column connections in buildings was observed in the Northridge and Kobe earthquakes. Despite the structural importance of such connections, it can be difficult to locate damage in structural members underneath superficial building features. We have developed a novel technique to locate fracturing welds in buildings in real time using high-frequency information from seismograms. Numerical and experimental methods were used to investigate an approach for detecting the brittle fracture of welds of beam-column connections in instrumented steel moment-frame buildings through the use of time-reversed Green’s functions and wave propagation reciprocity. The approach makes use of a prerecorded catalogue of Green’s functions for an instrumented building to detect high-frequency failure events in the building during a later earthquake by screening continuous data for the presence of one or more of the events. This was explored experimentally by comparing structural responses of a small-scale laboratory structure under a variety of loading conditions. Experimentation was conducted on a polyvinyl chloride frame model structure with data recorded at a sample rate of 2000 Hz using piezoelectric accelerometers and a 24-bit digitizer. Green’s functions were obtained by applying impulsive force loads at various locations along the structure with a rubber-tipped force transducer hammer. We performed a blind test using cross-correlation techniques to determine if it was possible to use the catalogue of Green’s functions to pinpoint the absolute times and locations of subsequent, induced failure events in the structure. A finite-element method was used to simulate the response of the model structure to various source mechanisms in order to determine the types of elastic waves that were produced as well as to obtain a general understanding of the structural response to localized loading and fracture.

  18. Frequency interleaving towards spectrally efficient directly detected optical OFDM for next-generation optical access networks.

    Science.gov (United States)

    Mehedy, Lenin; Bakaul, Masuduzzaman; Nirmalathas, Ampalavanapillai

    2010-10-25

    In this paper, we theoretically analyze and demonstrate that spectral efficiency of a conventional direct detection based optical OFDM system (DDO-OFDM) can be improved significantly using frequency interleaving of adjacent DDO-OFDM channels where OFDM signal band of one channel occupies the spectral gap of other channel and vice versa. We show that, at optimum operating condition, the proposed technique can effectively improve the spectral efficiency of the conventional DDO-OFDM system as much as 50%. We also show that such a frequency interleaved DDO-OFDM system, with a bit rate of 48 Gb/s within 25 GHz bandwidth, achieves sufficient power budget after transmission over 25 km single mode fiber to be used in next-generation time-division-multiplexed passive optical networks (TDM-PON). Moreover, by applying 64- quadrature amplitude modulation (QAM), the system can be further scaled up to 96 Gb/s with a power budget sufficient for 1:16 split TDM-PON.

  19. Using Low-Frequency Phased Arrays to Detect Cracks in Cast Austenitic Piping Components

    International Nuclear Information System (INIS)

    Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

    2005-01-01

    As part of a multi-year program funded by the United States Nuclear Regulatory Commission (US NRC) to address NDE reliability of inservice inspection (ISI) programs, recent studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, have focused on assessing novel NDE approaches for the inspection of coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the US NRC on the utility, effectiveness and reliability of ultrasonic testing (UT) and eddy current testing (ET) inspection techniques as related to the ISI of primary piping components in pressurized water reactors (PWRs). This paper describes progress, recent developments and early results from an assessment of a portion of this work relating to the ultrasonic low frequency phased array inspection technique. Westinghouse Owner's Group (WOG) cast stainless steel pipe segments with thermal and mechanical fatigue cracks, PNNL samples containing thermal fatigue cracks and several blank vintage specimens having very coarse grains that are representative of early centrifugally cast piping installed in PWRs, are being used for assessing the inspection method. The phased array approach was implemented using an R/D Tech Tomoscan III system operating at 1.0 MHz and 500 kHz, providing composite volumetric images of the samples. Several dual, transmit-receive, custom designed low-frequency arrays are employed in laboratory trials. Results from laboratory studies for assessing detection of thermal and mechanical fatigue cracks in cast stainless steel piping welds are discussed

  20. Low Frequency Phased Array Application for Crack Detection in Cast Austenitic Piping

    International Nuclear Information System (INIS)

    Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

    2006-01-01

    As part of a multi-year program funded by the United States Nuclear Regulatory Commission (US NRC) to address nondestructive examination (NDE) reliability of inservice inspection (ISI) programs, studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, have focused on assessing novel NDE approaches for the inspection of coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the US NRC on the utility, effectiveness and reliability of ultrasonic testing (UT) as related to the ISI of primary piping components in US commercial nuclear power plants. This paper describes progress, recent developments and results from an assessment of a portion of the work relating to the ultrasonic low frequency phased array inspection technique. Westinghouse Owner's Group (WOG) cast stainless steel pipe segments with thermal and mechanical fatigue cracks, PNNL samples containing thermal fatigue cracks and several blank vintage specimens having very coarse grains that are representative of early centrifugally cast piping installed in PWRs, were used for assessing the inspection method. The phased array approach was implemented using an R/D Tech Tomoscan III system operating at 1.0 MHz and 500 kHz, providing composite volumetric images of the samples. Several dual, transmit-receive, custom designed low-frequency arrays were employed in laboratory trials. Results from laboratory studies for assessing detection, localization and length sizing effectiveness are discussed.

  1. Higher frequency of secretor phenotype in O blood group ? its benefits in prevention and/or treatment of some diseases

    OpenAIRE

    Jaff, Mohamad Salih

    2010-01-01

    Mohamad Salih JaffPathology Department, Hawler Medical University (Formerly Salahaddin University), Erbil, Kurdistan Region, IraqAbstract: ABO blood groups and secretor status are important in clinical and forensic medicine and in relation to some diseases. There are geographic and racial differences in their frequencies, but the frequency of secretor status in different ABO blood group systems has not been determined yet. Therefore, the aim of this study was mainly to determine this point. B...

  2. Combining time-frequency and spatial information for the detection of sleep spindles

    Directory of Open Access Journals (Sweden)

    Christian eO'Reilly

    2015-02-01

    Full Text Available EEG sleep spindles are short (0.5-2.0 s bursts of activity in the 11-16 Hz band occurring during non-rapid eye movement (NREM sleep. This sporadic activity is thought to play a role in memory consolidation, brain plasticity, and protection of sleep integrity. Many automatic detectors have been proposed to assist or replace experts for sleep spindle scoring. However, these algorithms usually detect too many events making it difficult to achieve a good tradeoff between sensitivity (Se and false detection rate (FDr. In this work, we propose a semi-automatic detector comprising a sensitivity phase based on well-established criteria followed by a specificity phase using spatial and spectral criteria.In the sensitivity phase, selected events are those which amplitude in the 10 – 16 Hz band and spectral ratio characteristics both reject a null hypothesis (p <0.1 stating that the considered event is not a spindle. This null hypothesis is constructed from events occurring during rapid eye movement (REM sleep epochs. In the specificity phase, a hierarchical clustering of the selected candidates is done based on events’ frequency and spatial position along the anterior-posterior axis. Only events from the classes grouping most (at least 80% spindles scored by an expert are kept. We obtain Se = 93.2% and FDr = 93.0% in the first phase and Se = 85.4% and FDr = 86.2% in the second phase. For these two phases, Matthew’s correlation coefficients are respectively 0.228 and 0.324. Results suggest that spindles are defined by specific spatio-spectral properties and that automatic detection methods can be improved by considering these features.

  3. Frequency-swept laser light source at 1050 nm with higher bandwidth due to multiple semiconductor optical amplifiers in series

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Thrane, Lars; Andersen, Peter E.

    2009-01-01

    We report on the development of an all-fiber frequency-swept laser light source in the 1050 nm range based on semiconductor optical amplifiers (SOA) with improved bandwidth due to multiple gain media. It is demonstrated that even two SOAs with nearly equal gain spectra can improve the performance...

  4. Signal existence verification (SEV) for GPS low received power signal detection using the time-frequency approach.

    Science.gov (United States)

    Jan, Shau-Shiun; Sun, Chih-Cheng

    2010-01-01

    The detection of low received power of global positioning system (GPS) signals in the signal acquisition process is an important issue for GPS applications. Improving the miss-detection problem of low received power signal is crucial, especially for urban or indoor environments. This paper proposes a signal existence verification (SEV) process to detect and subsequently verify low received power GPS signals. The SEV process is based on the time-frequency representation of GPS signal, and it can capture the characteristic of GPS signal in the time-frequency plane to enhance the GPS signal acquisition performance. Several simulations and experiments are conducted to show the effectiveness of the proposed method for low received power signal detection. The contribution of this work is that the SEV process is an additional scheme to assist the GPS signal acquisition process in low received power signal detection, without changing the original signal acquisition or tracking algorithms.

  5. A Robust Motion Artifact Detection Algorithm for Accurate Detection of Heart Rates From Photoplethysmographic Signals Using Time-Frequency Spectral Features.

    Science.gov (United States)

    Dao, Duy; Salehizadeh, S M A; Noh, Yeonsik; Chong, Jo Woon; Cho, Chae Ho; McManus, Dave; Darling, Chad E; Mendelson, Yitzhak; Chon, Ki H

    2017-09-01

    Motion and noise artifacts (MNAs) impose limits on the usability of the photoplethysmogram (PPG), particularly in the context of ambulatory monitoring. MNAs can distort PPG, causing erroneous estimation of physiological parameters such as heart rate (HR) and arterial oxygen saturation (SpO2). In this study, we present a novel approach, "TifMA," based on using the time-frequency spectrum of PPG to first detect the MNA-corrupted data and next discard the nonusable part of the corrupted data. The term "nonusable" refers to segments of PPG data from which the HR signal cannot be recovered accurately. Two sequential classification procedures were included in the TifMA algorithm. The first classifier distinguishes between MNA-corrupted and MNA-free PPG data. Once a segment of data is deemed MNA-corrupted, the next classifier determines whether the HR can be recovered from the corrupted segment or not. A support vector machine (SVM) classifier was used to build a decision boundary for the first classification task using data segments from a training dataset. Features from time-frequency spectra of PPG were extracted to build the detection model. Five datasets were considered for evaluating TifMA performance: (1) and (2) were laboratory-controlled PPG recordings from forehead and finger pulse oximeter sensors with subjects making random movements, (3) and (4) were actual patient PPG recordings from UMass Memorial Medical Center with random free movements and (5) was a laboratory-controlled PPG recording dataset measured at the forehead while the subjects ran on a treadmill. The first dataset was used to analyze the noise sensitivity of the algorithm. Datasets 2-4 were used to evaluate the MNA detection phase of the algorithm. The results from the first phase of the algorithm (MNA detection) were compared to results from three existing MNA detection algorithms: the Hjorth, kurtosis-Shannon entropy, and time-domain variability-SVM approaches. This last is an approach

  6. A comparison of two sleep spindle detection methods based on all night averages: individually adjusted versus fixed frequencies

    Directory of Open Access Journals (Sweden)

    Péter Przemyslaw Ujma

    2015-02-01

    Full Text Available Sleep spindles are frequently studied for their relationship with state and trait cognitive variables, and they are thought to play an important role in sleep-related memory consolidation. Due to their frequent occurrence in NREM sleep, the detection of sleep spindles is only feasible using automatic algorithms, of which a large number is available. We compared subject averages of the spindle parameters computed by a fixed frequency (11-13 Hz for slow spindles, 13-15 Hz for fast spindles automatic detection algorithm and the individual adjustment method (IAM, which uses individual frequency bands for sleep spindle detection. Fast spindle duration and amplitude are strongly correlated in the two algorithms, but there is little overlap in fast spindle density and slow spindle parameters in general. The agreement between fixed and manually determined sleep spindle frequencies is limited, especially in case of slow spindles. This is the most likely reason for the poor agreement between the two detection methods in case of slow spindle parameters. Our results suggest that while various algorithms may reliably detect fast spindles, a more sophisticated algorithm primed to individual spindle frequencies is necessary for the detection of slow spindles as well as individual variations in the number of spindles in general.

  7. Doppler Radar Vital Signs Detection Method Based on Higher Order Cyclostationary.

    Science.gov (United States)

    Yu, Zhibin; Zhao, Duo; Zhang, Zhiqiang

    2017-12-26

    Due to the non-contact nature, using Doppler radar sensors to detect vital signs such as heart and respiration rates of a human subject is getting more and more attention. However, the related detection-method research meets lots of challenges due to electromagnetic interferences, clutter and random motion interferences. In this paper, a novel third-order cyclic cummulant (TOCC) detection method, which is insensitive to Gaussian interference and non-cyclic signals, is proposed to investigate the heart and respiration rate based on continuous wave Doppler radars. The k -th order cyclostationary properties of the radar signal with hidden periodicities and random motions are analyzed. The third-order cyclostationary detection theory of the heart and respiration rate is studied. Experimental results show that the third-order cyclostationary approach has better estimation accuracy for detecting the vital signs from the received radar signal under low SNR, strong clutter noise and random motion interferences.

  8. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y., E-mail: thuzhangyu@foxmail.com; Huang, S. L., E-mail: huangsling@tsinghua.edu.cn; Wang, S.; Zhao, W. [State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China)

    2016-05-15

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert–Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of <1% and thus can act as a universal time-of-flight extraction method for narrowband Lamb wave detection signals.

  9. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals

    International Nuclear Information System (INIS)

    Zhang, Y.; Huang, S. L.; Wang, S.; Zhao, W.

    2016-01-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert–Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of <1% and thus can act as a universal time-of-flight extraction method for narrowband Lamb wave detection signals.

  10. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals.

    Science.gov (United States)

    Zhang, Y; Huang, S L; Wang, S; Zhao, W

    2016-05-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert-Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of wave detection signals.

  11. Bimodal atomic force microscopy driving the higher eigenmode in frequency-modulation mode: Implementation, advantages, disadvantages and comparison to the open-loop case.

    Science.gov (United States)

    Ebeling, Daniel; Solares, Santiago D

    2013-01-01

    We present an overview of the bimodal amplitude-frequency-modulation (AM-FM) imaging mode of atomic force microscopy (AFM), whereby the fundamental eigenmode is driven by using the amplitude-modulation technique (AM-AFM) while a higher eigenmode is driven by using either the constant-excitation or the constant-amplitude variant of the frequency-modulation (FM-AFM) technique. We also offer a comparison to the original bimodal AFM method, in which the higher eigenmode is driven with constant frequency and constant excitation amplitude. General as well as particular characteristics of the different driving schemes are highlighted from theoretical and experimental points of view, revealing the advantages and disadvantages of each. This study provides information and guidelines that can be useful in selecting the most appropriate operation mode to characterize different samples in the most efficient and reliable way.

  12. An Automated Measurement of Ciliary Beating Frequency using a Combined Optical Flow and Peak Detection.

    Science.gov (United States)

    Kim, Woojae; Han, Tae Hwa; Kim, Hyun Jun; Park, Man Young; Kim, Ku Sang; Park, Rae Woong

    2011-06-01

    The mucociliary transport system is a major defense mechanism of the respiratory tract. The performance of mucous transportation in the nasal cavity can be represented by a ciliary beating frequency (CBF). This study proposes a novel method to measure CBF by using optical flow. To obtain objective estimates of CBF from video images, an automated computer-based image processing technique is developed. This study proposes a new method based on optical flow for image processing and peak detection for signal processing. We compare the measuring accuracy of the method in various combinations of image processing (optical flow versus difference image) and signal processing (fast Fourier transform [FFT] vs. peak detection [PD]). The digital high-speed video method with a manual count of CBF in slow motion video play, is the gold-standard in CBF measurement. We obtained a total of fifty recorded ciliated sinonasal epithelium images to measure CBF from the Department of Otolaryngology. The ciliated sinonasal epithelium images were recorded at 50-100 frames per second using a charge coupled device camera with an inverted microscope at a magnification of ×1,000. The mean square errors and variance for each method were 1.24, 0.84 Hz; 11.8, 2.63 Hz; 3.22, 1.46 Hz; and 3.82, 1.53 Hz for optical flow (OF) + PD, OF + FFT, difference image [DI] + PD, and DI + FFT, respectively. Of the four methods, PD using optical flow showed the best performance for measuring the CBF of nasal mucosa. The proposed method was able to measure CBF more objectively and efficiently than what is currently possible.

  13. Eating frequency is higher in weight loss maintainers and normal-weight individuals than in overweight individuals.

    Science.gov (United States)

    Bachman, Jessica L; Phelan, Suzanne; Wing, Rena R; Raynor, Hollie A

    2011-11-01

    Eating frequency has been negatively related to body mass index (BMI). The relationship between eating frequency and weight loss maintenance is unknown. This secondary analysis examined eating frequency (self-reported meals and snacks consumed per day) in weight loss maintainers (WLM) who had reduced from overweight/obese to normal weight, normal weight (NW) individuals, and overweight (OW) individuals. Data collected July 2006 to March 2007 in Providence, RI, included three 24-hour dietary recalls (2 weekdays, 1 weekend day) analyzed using Nutrient Data System for Research software from 257 adults (WLM n=96, 83.3% women aged 50.0±11.8 years with BMI 22.1±1.7; NW n=80, 95.0% women aged 46.1±11.5 years with BMI 21.1±1.4; OW n=81, 53.1% women aged 51.4±9.0 years with BMI 34.2±4.1) with plausible intakes. Participant-defined meals and snacks were ≥50 kcal and separated by more than 1 hour. Self-reported physical activity was highest in WLM followed by NW, and then OW (3,097±2,572 kcal/week, 2,062±1,286 kcal/week, and 785±901 kcal/week, respectively; Pmeals consumed (2.7±0.4 meals/day). Eating frequency, particularly in regard to a pattern of three meals and two snacks per day, may be important in weight loss maintenance. Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

  14. Detrimental Effect Elimination of Laser Frequency Instability in Brillouin Optical Time Domain Reflectometer by Using Self-Heterodyne Detection

    Directory of Open Access Journals (Sweden)

    Yongqian Li

    2017-03-01

    Full Text Available A useful method for eliminating the detrimental effect of laser frequency instability on Brillouin signals by employing the self-heterodyne detection of Rayleigh and Brillouin scattering is presented. From the analysis of Brillouin scattering spectra from fibers with different lengths measured by heterodyne detection, the maximum usable pulse width immune to laser frequency instability is obtained to be about 4 µs in a self-heterodyne detection Brillouin optical time domain reflectometer (BOTDR system using a broad-band laser with low frequency stability. Applying the self-heterodyne detection of Rayleigh and Brillouin scattering in BOTDR system, we successfully demonstrate that the detrimental effect of laser frequency instability on Brillouin signals can be eliminated effectively. Employing the broad-band laser modulated by a 130-ns wide pulse driven electro-optic modulator, the observed maximum errors in temperatures measured by the local heterodyne and self-heterodyne detection BOTDR systems are 7.9 °C and 1.2 °C, respectively.

  15. Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI

    Science.gov (United States)

    Fish, Vincent L.; Doeleman, Sheperd S.; Broderick, Avery E.; Loeb, Abraham; Rogers, Alan E. E.

    2009-12-01

    Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center. In the submillimeter regime, Sgr A* exhibits time-variable linear polarization on timescales corresponding to errors. Although the source-integrated linear polarization fraction in the models is typically only a few percent, the linear polarization fraction on small angular scales can be much higher, enabling the detection of changes in the polarimetric structure of Sgr A* on a wide variety of baselines. The shortest baselines track the source-integrated linear polarization fraction, while longer baselines are sensitive to polarization substructures that are beam-diluted by connected-element interferometry. The detection of periodic variability in source polarization should not be significantly affected even if instrumental polarization terms cannot be calibrated out. As more antennas are included in the (sub)millimeter-VLBI array, observations with full polarization will provide important new diagnostics to help disentangle intrinsic source polarization from Faraday rotation effects in the accretion and outflow region close to the black hole event horizon.

  16. DETECTING CHANGING POLARIZATION STRUCTURES IN SAGITTARIUS A* WITH HIGH FREQUENCY VLBI

    Energy Technology Data Exchange (ETDEWEB)

    Fish, Vincent L; Doeleman, Sheperd S; Rogers, Alan E. E. [Massachusetts Institute of Technology, Haystack Observatory, Route 40, Westford, MA 01886 (United States); Broderick, Avery E [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Loeb, Abraham [Institute for Theory and Computation, Harvard University, Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2009-12-01

    Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center. In the submillimeter regime, Sgr A* exhibits time-variable linear polarization on timescales corresponding to <10 Schwarzschild radii of the presumed 4 x 10{sup 6} M {sub sun} black hole. In previous work, we demonstrated the potential for total-intensity (sub)millimeter-wavelength very long baseline interferometry (VLBI) to detect time-variable-and periodic-source structure changes in the Sgr A* black hole system using nonimaging analyses. Here, we extend this work to include full polarimetric VLBI observations. We simulate full-polarization (sub)millimeter VLBI data of Sgr A* using a hot spot model that is embedded within an accretion disk, with emphasis on nonimaging polarimetric data products that are robust against calibration errors. Although the source-integrated linear polarization fraction in the models is typically only a few percent, the linear polarization fraction on small angular scales can be much higher, enabling the detection of changes in the polarimetric structure of Sgr A* on a wide variety of baselines. The shortest baselines track the source-integrated linear polarization fraction, while longer baselines are sensitive to polarization substructures that are beam-diluted by connected-element interferometry. The detection of periodic variability in source polarization should not be significantly affected even if instrumental polarization terms cannot be calibrated out. As more antennas are included in the (sub)millimeter-VLBI array, observations with full polarization will provide important new diagnostics to help disentangle intrinsic source polarization from Faraday rotation effects in the accretion and outflow region close to the black hole event horizon.

  17. DETECTING CHANGING POLARIZATION STRUCTURES IN SAGITTARIUS A* WITH HIGH FREQUENCY VLBI

    International Nuclear Information System (INIS)

    Fish, Vincent L.; Doeleman, Sheperd S.; Rogers, Alan E. E.; Broderick, Avery E.; Loeb, Abraham

    2009-01-01

    Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center. In the submillimeter regime, Sgr A* exhibits time-variable linear polarization on timescales corresponding to 6 M sun black hole. In previous work, we demonstrated the potential for total-intensity (sub)millimeter-wavelength very long baseline interferometry (VLBI) to detect time-variable-and periodic-source structure changes in the Sgr A* black hole system using nonimaging analyses. Here, we extend this work to include full polarimetric VLBI observations. We simulate full-polarization (sub)millimeter VLBI data of Sgr A* using a hot spot model that is embedded within an accretion disk, with emphasis on nonimaging polarimetric data products that are robust against calibration errors. Although the source-integrated linear polarization fraction in the models is typically only a few percent, the linear polarization fraction on small angular scales can be much higher, enabling the detection of changes in the polarimetric structure of Sgr A* on a wide variety of baselines. The shortest baselines track the source-integrated linear polarization fraction, while longer baselines are sensitive to polarization substructures that are beam-diluted by connected-element interferometry. The detection of periodic variability in source polarization should not be significantly affected even if instrumental polarization terms cannot be calibrated out. As more antennas are included in the (sub)millimeter-VLBI array, observations with full polarization will provide important new diagnostics to help disentangle intrinsic source polarization from Faraday rotation effects in the accretion and outflow region close to the black hole event horizon.

  18. Using a higher criticism statistic to detect modest effects in a genome-wide study of rheumatoid arthritis

    Science.gov (United States)

    2009-01-01

    In high-dimensional studies such as genome-wide association studies, the correction for multiple testing in order to control total type I error results in decreased power to detect modest effects. We present a new analytical approach based on the higher criticism statistic that allows identification of the presence of modest effects. We apply our method to the genome-wide study of rheumatoid arthritis provided in the Genetic Analysis Workshop 16 Problem 1 data set. There is evidence for unknown bias in this study that could be explained by the presence of undetected modest effects. We compared the asymptotic and empirical thresholds for the higher criticism statistic. Using the asymptotic threshold we detected the presence of modest effects genome-wide. We also detected modest effects using 90th percentile of the empirical null distribution as a threshold; however, there is no such evidence when the 95th and 99th percentiles were used. While the higher criticism method suggests that there is some evidence for modest effects, interpreting individual single-nucleotide polymorphisms with significant higher criticism statistics is of undermined value. The goal of higher criticism is to alert the researcher that genetic effects remain to be discovered and to promote the use of more targeted and powerful studies to detect the remaining effects. PMID:20018032

  19. A comparative assessment of different frequency based damage detection in unidirectional composite plates using MFC sensors

    Science.gov (United States)

    de Medeiros, Ricardo; Sartorato, Murilo; Vandepitte, Dirk; Tita, Volnei

    2016-11-01

    The basic concept of the vibration based damage identification methods is that the dynamic behaviour of a structure can change if damage occurs. Damage in a structure can alter the structural integrity, and therefore, the physical properties like stiffness, mass and/or damping may change. The dynamic behaviour of a structure is a function of these physical properties and will, therefore, directly be affected by the damage. The dynamic behaviour can be described in terms of time, frequency and modal domain parameters. The changes in these parameters (or properties derived from these parameters) are used as indicators of damage. Hence, this work has two main objectives. The first one is to provide an overview of the structural vibration based damage identification methods. For this purpose, a fundamental description of the structural vibration based damage identification problem is given, followed by a short literature overview of the damage features, which are commonly addressed. The second objective is to create a damage identification method for detection of the damage in composite structures. To aid in this process, two basic principles are discussed, namely the effect of the potential damage case on the dynamic behaviour, and the consequences involved with the information reduction in the signal processing. Modal properties from the structural dynamic output response are obtained. In addition, experimental and computational results are presented for the application of modal analysis techniques applied to composite specimens with and without damage. The excitation of the structures is performed using an impact hammer and, for measuring the output data, accelerometers as well as piezoelectric sensors. Finite element models are developed by shell elements, and numerical results are compared to experimental data, showing good correlation for the response of the specimens in some specific frequency range. Finally, FRFs are analysed using suitable metrics, including a

  20. Host-Parasite Interactions in Individuals with Type 1 and 2 Diabetes Result in Higher Frequency of Ascaris lumbricoides and Giardia lamblia in Type 2 Diabetic Individuals

    Directory of Open Access Journals (Sweden)

    Eleuza Rodrigues Machado

    2018-01-01

    Full Text Available Host-parasite interactions in diabetic patients might influence diabetes complications and intestinal parasitosis. The aim was to investigate the occurrence of enteroparasites in individuals with diabetes types 1 and 2. A descriptive study was designed to estimate frequencies of parasites and to compare them in individuals with diabetes types 1 and 2 from two Health Centers and one hospital in the Federal District of Brazil. Patients were allocated to the study by convenience. Three fecal samples of 156 diabetic individuals (120 type 1 and 36 type 2 were analyzed using two parasitological methods. Enteroparasites or commensals frequency in diabetics was 64%. Diabetics infected with up to six species of intestinal parasites or commensals were found. Frequencies of Ascaris lumbricoides and Giardia lamblia were higher in individuals with type 2 diabetes. The lower frequency of A. lumbricoides found in type 1 diabetes may be related to a strong Th2 response to parasites. Autoimmune response developed in type 1 diabetic individuals characterized by the production of Th1 cytokines could explain low frequency of G. lamblia. High frequency of parasites found in type 2 diabetes emphasizes the importance of periodic parasitological examinations in these individuals.

  1. Exploiting Higher Order and Multi-modal Features for 3D Object Detection

    DEFF Research Database (Denmark)

    Kiforenko, Lilita

    that describe object visual appearance such as shape, colour, texture etc. This thesis focuses on robust object detection and pose estimation of rigid objects using 3D information. The thesis main contributions are novel feature descriptors together with object detection and pose estimation algorithms....... The initial work introduces a feature descriptor that uses edge categorisation in combination with a local multi-modal histogram descriptor in order to detect objects with little or no texture or surface variation. The comparison is performed with a state-of-the-art method, which is outperformed...... of the methods work well for one type of objects in a specific scenario, in another scenario or with different objects they might fail, therefore more robust solutions are required. The typical problem solution is the design of robust feature descriptors, where feature descriptors contain information...

  2. Comparison of three cell block techniques for detection of low frequency abnormal cells

    Directory of Open Access Journals (Sweden)

    McCormack M

    2013-01-01

    Full Text Available Steven A Hecht, Matthew McCormackHologic Inc, Marlborough, MA, USABackground: The Cellient® Automated Cell Block System rapidly creates paraffin-embedded cell blocks by using vacuum filtration to deposit a layer of cells on a filter and infiltrate those cells with reagents and paraffin. This study used a “tracer” cell model to mimic low frequency abnormal cells and compare detection and representative sampling with simple sedimentation, Richard-Allan HistoGel™, and Cellient cell block techniques.Methods: Tracer cells were a cultured cell line (CaSki fixed in methanol, prestained in solution with hematoxylin, and quantified using a hemacytometer. Tracer cells were diluted in a 10-fold dilution series ranging from 100 to 0.1 tracer/mL in a background of pooled clinical serous effusion specimens. Ten replicates of each dilution were processed using each cell block method, and the resulting blocks were cut to produce two slides from each block. The slides were deparaffinized, counterstained with eosin, cover-slipped, and screened for the presence of tracer cells. Blocks were considered to be representative of the specimen if tracer cells were detected on either of the slides. If no tracer cells were observed on either slide, the block was recut to generate a third slide. If tracer cells were seen on the third slide, the block was considered representative of the specimen.Results: Tracer cells were identified on the initial slides for 20 of 40 (50.0% simple sedimentation, 21 of 40 (52.5% of HistoGel, and 25 of 40 (62.5% of Cellient cell blocks. Representative sampling of the 1 tracer/mL specimen was 10.0% for simple sedimentation and 30.0% for HistoGel and Cellient. Only Cellient showed representative sampling of the 0.1 tracer/mL specimen.Conclusion: The Cellient System blocks demonstrated representative sampling at the lowest tracer cell concentration compared with simple sedimentation and HistoGel.Keywords: Cellient®, HistoGel™, simple

  3. Corrections to “Change Detection in Full and Dual Polarization, Single- and Multi-Frequency SAR Data”

    DEFF Research Database (Denmark)

    Nielsen, Allan Aasbjerg; Conradsen, Knut; Skriver, Henning

    2017-01-01

    of obtaining a smaller value of the test statistic are given. In a case study airborne EMISAR C- and L-band SAR images from the spring of 1998 covering agricultural fields and wooded areas near Foulum, Denmark, are used in single- and bi-frequency, bi-temporal change detection with full and dual polarimetry...

  4. Comparison of intensity discrimination, increment detection, and comodulation masking release in the envelope and audio-frequency domains

    DEFF Research Database (Denmark)

    Nelson, Paul C.; Ewert, Stephan; Carney, Laurel H.

    In the audio-frequency domain, the envelope apparently plays an important role in detection of intensity increments and in comodulation masking release (CMR). The current study addressed the question whether the second-order envelope ("venelope") contributes similarly for comparable experiments i...

  5. Detection of MPLW515L/K mutations and determination of allele frequencies with a single-tube PCR assay.

    Science.gov (United States)

    Takei, Hiraku; Morishita, Soji; Araki, Marito; Edahiro, Yoko; Sunami, Yoshitaka; Hironaka, Yumi; Noda, Naohiro; Sekiguchi, Yuji; Tsuneda, Satoshi; Ohsaka, Akimichi; Komatsu, Norio

    2014-01-01

    A gain-of-function mutation in the myeloproliferative leukemia virus (MPL) gene, which encodes the thrombopoietin receptor, has been identified in patients with essential thrombocythemia and primary myelofibrosis, subgroups of classic myeloproliferative neoplasms (MPNs). The presence of MPL gene mutations is a critical diagnostic criterion for these diseases. Here, we developed a rapid, simple, and cost-effective method of detecting two major MPL mutations, MPLW515L/K, in a single PCR assay; we termed this method DARMS (dual amplification refractory mutation system)-PCR. DARMS-PCR is designed to produce three different PCR products corresponding to MPLW515L, MPLW515K, and all MPL alleles. The amplicons are later detected and quantified using a capillary sequencer to determine the relative frequencies of the mutant and wild-type alleles. Applying DARMS-PCR to human specimens, we successfully identified MPL mutations in MPN patients, with the exception of patients bearing mutant allele frequencies below the detection limit (5%) of this method. The MPL mutant allele frequencies determined using DARMS-PCR correlated strongly with the values determined using deep sequencing. Thus, we demonstrated the potential of DARMS-PCR to detect MPL mutations and determine the allele frequencies in a timely and cost-effective manner.

  6. Detection of MPLW515L/K mutations and determination of allele frequencies with a single-tube PCR assay.

    Directory of Open Access Journals (Sweden)

    Hiraku Takei

    Full Text Available A gain-of-function mutation in the myeloproliferative leukemia virus (MPL gene, which encodes the thrombopoietin receptor, has been identified in patients with essential thrombocythemia and primary myelofibrosis, subgroups of classic myeloproliferative neoplasms (MPNs. The presence of MPL gene mutations is a critical diagnostic criterion for these diseases. Here, we developed a rapid, simple, and cost-effective method of detecting two major MPL mutations, MPLW515L/K, in a single PCR assay; we termed this method DARMS (dual amplification refractory mutation system-PCR. DARMS-PCR is designed to produce three different PCR products corresponding to MPLW515L, MPLW515K, and all MPL alleles. The amplicons are later detected and quantified using a capillary sequencer to determine the relative frequencies of the mutant and wild-type alleles. Applying DARMS-PCR to human specimens, we successfully identified MPL mutations in MPN patients, with the exception of patients bearing mutant allele frequencies below the detection limit (5% of this method. The MPL mutant allele frequencies determined using DARMS-PCR correlated strongly with the values determined using deep sequencing. Thus, we demonstrated the potential of DARMS-PCR to detect MPL mutations and determine the allele frequencies in a timely and cost-effective manner.

  7. Further detection of the optical low frequency QPO in the black hole transient MAXI J1820+070

    Science.gov (United States)

    Yu, Wenfei; Lin, Jie; Mao, Dongming; Zhang, Jujia; Yan, Zhen; Bai, Jinming

    2018-05-01

    We report on the optical photometric observation of MAXI J1820+070 with the 2.4m telescope at Lijiang Gaomeigu Station of Yunnan observatories with our Fast Optical Camera (FOC) on April 22, 2018, following the detection of low frequency QPO in the optical band (ATEL #11510).

  8. Polarization switching detection method using a ferroelectric liquid crystal for dichroic atomic vapor laser lock frequency stabilization techniques.

    Science.gov (United States)

    Dudzik, Grzegorz; Rzepka, Janusz; Abramski, Krzysztof M

    2015-04-01

    We present a concept of the polarization switching detection method implemented for frequency-stabilized lasers, called the polarization switching dichroic atomic vapor laser lock (PSDAVLL) technique. It is a combination of the well-known dichroic atomic vapor laser lock method for laser frequency stabilization with a synchronous detection system based on the surface-stabilized ferroelectric liquid crystal (SSFLC).The SSFLC is a polarization switch and quarter wave-plate component. This technique provides a 9.6 dB better dynamic range ratio (DNR) than the well-known two-photodiode detection configuration known as the balanced polarimeter. This paper describes the proposed method used practically in the VCSEL laser frequency stabilization system. The applied PSDAVLL method has allowed us to obtain a frequency stability of 2.7×10⁻⁹ and a reproducibility of 1.2×10⁻⁸, with a DNR of detected signals of around 81 dB. It has been shown that PSDAVLL might be successfully used as a method for spectra-stable laser sources.

  9. Higher plant availability and reduced reactor scram frequency in PWRs by appropriate system and I and C design

    International Nuclear Information System (INIS)

    Frei, G.; Weber, J.

    1987-01-01

    High plant availability and reliability are guaranteed by appropriate design of reactor and BOP systems, this including the plant I and C systems. It is of advantage to have design, construction and commissioning of the plant concentrated in the hands of a single company to avoid interface problems between the different areas of the plant. The integrated overall control concept developed by KWU with control, limitation and protection systems as well as optimized operational and monitoring systems assisted by instrumentation channel redundance and logic for selection of the second highest (or second lowest) signal value as appropriate for comparison with limitation setpoints, minimize the severity of transients. This results in a reduction in the frequency of reactor scrams and of unnecessary actuation of safety systems. Dynamic plant behavior is described for a number of examples where the improved plant behavior resulting from the above design features enhances plant availability

  10. Comparison of level discrimination, increment detection, and comodulation masking release in the audio- and envelope-frequency domains

    DEFF Research Database (Denmark)

    Nelson, Paul C.; Ewert, Stephan; Carney, Laurel H.

    2007-01-01

    In general, the temporal structure of stimuli must be considered to account for certain observations made in detection and masking experiments in the audio-frequency domain. Two such phenomena are (1) a heightened sensitivity to amplitude increments with a temporal fringe compared to gated level......-frequency domain. Pure-tone carrier amplitude-modulation (AM) depth-discrimination thresholds were found to be similar using both traditional gated stimuli and using a temporally modulated fringe for a fixed standard depth (ms=0.25) and a range of AM frequencies (4-64 Hz). In a second experiment, masked sinusoidal...... AM detection thresholds were compared in conditions with and without slow and regular fluctuations imposed on the instantaneous masker AM depth. Release from masking was obtained only for very slow masker fluctuations (less than 2 Hz). A physiologically motivated model that effectively acts...

  11. Does the Adoption of Plagiarism-Detection Software in Higher Education Reduce Plagiarism?

    Science.gov (United States)

    Youmans, Robert J.

    2011-01-01

    In two studies, students at California State University, Northridge wrote papers that were checked for plagiarism using plagiarism-detection software. In the first study, half of the students in two classes were randomly selected and told by the professor that their term papers would be scanned for plagiarism using the software. Students in the…

  12. Correlation analysis of extremely low-frequency variations of the natural electromagnetic Earth field and the problem of detecting periodical gravitational radiation

    International Nuclear Information System (INIS)

    Balakin, A.B.; Murzakhanov, Z.G.; Grunskaya, L.V.

    1994-01-01

    A proposal on the experimental detection of extremely low-frequency variations of the electromagnetic Earth field at the gravitational-wave frequency and method for correlation processing results of the experiments are described. 14 refs

  13. Edge Detection from High Resolution Remote Sensing Images using Two-Dimensional log Gabor Filter in Frequency Domain

    International Nuclear Information System (INIS)

    Wang, K; Yu, T; Meng, Q Y; Wang, G K; Li, S P; Liu, S H

    2014-01-01

    Edges are vital features to describe the structural information of images, especially high spatial resolution remote sensing images. Edge features can be used to define the boundaries between different ground objects in high spatial resolution remote sensing images. Thus edge detection is important in the remote sensing image processing. Even though many different edge detection algorithms have been proposed, it is difficult to extract the edge features from high spatial resolution remote sensing image including complex ground objects. This paper introduces a novel method to detect edges from the high spatial resolution remote sensing image based on frequency domain. Firstly, the high spatial resolution remote sensing images are Fourier transformed to obtain the magnitude spectrum image (frequency image) by FFT. Then, the frequency spectrum is analyzed by using the radius and angle sampling. Finally, two-dimensional log Gabor filter with optimal parameters is designed according to the result of spectrum analysis. Finally, dot product between the result of Fourier transform and the log Gabor filter is inverse Fourier transformed to obtain the detections. The experimental result shows that the proposed algorithm can detect edge features from the high resolution remote sensing image commendably

  14. A Technique for Real-Time Ionospheric Ranging Error Correction Based On Radar Dual-Frequency Detection

    Science.gov (United States)

    Lyu, Jiang-Tao; Zhou, Chen

    2017-12-01

    Ionospheric refraction is one of the principal error sources for limiting the accuracy of radar systems for space target detection. High-accuracy measurement of the ionospheric electron density along the propagation path of radar wave is the most important procedure for the ionospheric refraction correction. Traditionally, the ionospheric model and the ionospheric detection instruments, like ionosonde or GPS receivers, are employed for obtaining the electron density. However, both methods are not capable of satisfying the requirements of correction accuracy for the advanced space target radar system. In this study, we propose a novel technique for ionospheric refraction correction based on radar dual-frequency detection. Radar target range measurements at two adjacent frequencies are utilized for calculating the electron density integral exactly along the propagation path of the radar wave, which can generate accurate ionospheric range correction. The implementation of radar dual-frequency detection is validated by a P band radar located in midlatitude China. The experimental results present that the accuracy of this novel technique is more accurate than the traditional ionospheric model correction. The technique proposed in this study is very promising for the high-accuracy radar detection and tracking of objects in geospace.

  15. Noise Depression of Parasitic Capacitance for Frequency Detection of Micromechanical Bulk Disk Resonator

    DEFF Research Database (Denmark)

    Tang, Meng; Cagliani, Alberto; Escouflaire, Marie

    2010-01-01

    the frequency noise of the system. A capacitor cancellation circuit is used to subtract the parasitic capacitor. Measurements are conducted before and after the cancellation, and results show that after cancellation, the anti resonance is suppressed and the frequency noise is decreased, thus decreasing...

  16. Coherent laser radar with dual-frequency Doppler estimation and interferometric range detection

    NARCIS (Netherlands)

    Onori, D.; Scotti, F.; Laghezza, F.; Scaffardi, M.; Bogoni, A.

    2016-01-01

    The concept of a coherent interferometric dual frequency laser radar, that measures both the target range and velocity, is presented and experimentally demonstrated. The innovative architecture combines the dual frequency lidar concept, allowing a precise and robust Doppler estimation, with the

  17. Model-Based Fault Detection and Isolation of a Liquid-Cooled Frequency Converter on a Wind Turbine

    DEFF Research Database (Denmark)

    Li, Peng; Odgaard, Peter Fogh; Stoustrup, Jakob

    2012-01-01

    advanced fault detection and isolation schemes. In this paper, an observer-based fault detection and isolation method for the cooling system in a liquid-cooled frequency converter on a wind turbine which is built up in a scalar version in the laboratory is presented. A dynamic model of the scale cooling...... system is derived based on energy balance equation. A fault analysis is conducted to determine the severity and occurrence rate of possible component faults and their end effects in the cooling system. A method using unknown input observer is developed in order to detect and isolate the faults based...... on the developed dynamical model. The designed fault detection and isolation algorithm is applied on a set of measured experiment data in which different faults are artificially introduced to the scaled cooling system. The experimental results conclude that the different faults are successfully detected...

  18. Comparative Study of Time-Frequency Decomposition Techniques for Fault Detection in Induction Motors Using Vibration Analysis during Startup Transient

    Directory of Open Access Journals (Sweden)

    Paulo Antonio Delgado-Arredondo

    2015-01-01

    Full Text Available Induction motors are critical components for most industries and the condition monitoring has become necessary to detect faults. There are several techniques for fault diagnosis of induction motors and analyzing the startup transient vibration signals is not as widely used as other techniques like motor current signature analysis. Vibration analysis gives a fault diagnosis focused on the location of spectral components associated with faults. Therefore, this paper presents a comparative study of different time-frequency analysis methodologies that can be used for detecting faults in induction motors analyzing vibration signals during the startup transient. The studied methodologies are the time-frequency distribution of Gabor (TFDG, the time-frequency Morlet scalogram (TFMS, multiple signal classification (MUSIC, and fast Fourier transform (FFT. The analyzed vibration signals are one broken rotor bar, two broken bars, unbalance, and bearing defects. The obtained results have shown the feasibility of detecting faults in induction motors using the time-frequency spectral analysis applied to vibration signals, and the proposed methodology is applicable when it does not have current signals and only has vibration signals. Also, the methodology has applications in motors that are not fed directly to the supply line, in such cases the analysis of current signals is not recommended due to poor current signal quality.

  19. Sensitivity of new detection method for ultra-low frequency gravitational waves with pulsar spin-down rate statistics

    Science.gov (United States)

    Yonemaru, Naoyuki; Kumamoto, Hiroki; Takahashi, Keitaro; Kuroyanagi, Sachiko

    2018-04-01

    A new detection method for ultra-low frequency gravitational waves (GWs) with a frequency much lower than the observational range of pulsar timing arrays (PTAs) was suggested in Yonemaru et al. (2016). In the PTA analysis, ultra-low frequency GWs (≲ 10-10 Hz) which evolve just linearly during the observation time span are absorbed by the pulsar spin-down rates since both have the same effect on the pulse arrival time. Therefore, such GWs cannot be detected by the conventional method of PTAs. However, the bias on the observed spin-down rates depends on relative direction of a pulsar and GW source and shows a quadrupole pattern in the sky. Thus, if we divide the pulsars according to the position in the sky and see the difference in the statistics of the spin-down rates, ultra-low frequency GWs from a single source can be detected. In this paper, we evaluate the potential of this method by Monte-Carlo simulations and estimate the sensitivity, considering only the "Earth term" while the "pulsar term" acts like random noise for GW frequencies 10-13 - 10-10 Hz. We find that with 3,000 milli-second pulsars, which are expected to be discovered by a future survey with the Square Kilometre Array, GWs with the derivative of amplitude of about 3 × 10^{-19} {s}^{-1} can in principle be detected. Implications for possible supermassive binary black holes in Sgr* and M87 are also given.

  20. Will greenhouse gas-induced warming over the next 50 years lead to higher frequency and greater intensity of hurricanes?

    International Nuclear Information System (INIS)

    Bengtsson, L.; Botzet, M.; Esch, M.

    1994-01-01

    The use of a high resolution atmospheric model at T106 resolution, for studying the influence on greenhouse warming on tropical storm climatology, is investigated. The same method for identifying the storms has been used as in a previous study by Bengtsson et al (1994). The sea surface temperature anomalies have been taken from a previous climate change experiment, obtained with a low resolution ocean-atmosphere coupled model. The global distribution of the storms agree in their geographical position and seasonal variability with that of the present climate, but the number of storms is significantly reduced, particularly at the Southern hemisphere. The main reason to this is related to increased tropospheric stability, associated with increased warming at the upper troposphere and changes in the large scale circulation such as a weaker Hadley circulation and stronger upper air westerlies. The surface winds in the tropics are generally weaker and evaporation is also somewhat reduced, in spite of higher sea surface temperatures. (orig.)

  1. Study on the Application of an Ultra-High-Frequency Fractal Antenna to Partial Discharge Detection in Switchgears

    Directory of Open Access Journals (Sweden)

    Chenguo Yao

    2013-12-01

    Full Text Available The ultra-high-frequency (UHF method is used to analyze the insulation condition of electric equipment by detecting the UHF electromagnetic (EM waves excited by partial discharge (PD. As part of the UHF detection system, the UHF sensor determines the detection system performance in signal extraction and recognition. In this paper, a UHF antenna sensor with the fractal structure for PD detection in switchgears was designed by means of modeling, simulation and optimization. This sensor, with a flat-plate structure, had two resonance frequencies of 583 MHz and 732 MHz. In the laboratory, four kinds of insulation defect models were positioned in the testing switchgear for typical PD tests. The results show that the sensor could reproduce the electromagnetic waves well. Furthermore, to optimize the installation position of the inner sensor for achieving best detection performance, the precise simulation model of switchgear was developed to study the propagation characteristics of UHF signals in switchgear by finite-difference time-domain (FDTD method. According to the results of simulation and verification test, the sensor should be positioned at the right side of bottom plate in the front cabinet. This research established the foundation for the further study on the application of UHF technique in switchgear PD online detection.

  2. Real-time, high frequency QRS electrocardiograph with reduced amplitude zone detection

    Science.gov (United States)

    Schlegel, Todd T. (Inventor); DePalma, Jude L. (Inventor); Moradi, Saeed (Inventor)

    2009-01-01

    Real time cardiac electrical data are received from a patient, manipulated to determine various useful aspects of the ECG signal, and displayed in real time in a useful form on a computer screen or monitor. The monitor displays the high frequency data from the QRS complex in units of microvolts, juxtaposed with a display of conventional ECG data in units of millivolts or microvolts. The high frequency data are analyzed for their root mean square (RMS) voltage values and the discrete RMS values and related parameters are displayed in real time. The high frequency data from the QRS complex are analyzed with imbedded algorithms to determine the presence or absence of reduced amplitude zones, referred to herein as ''RAZs''. RAZs are displayed as ''go, no-go'' signals on the computer monitor. The RMS and related values of the high frequency components are displayed as time varying signals, and the presence or absence of RAZs may be similarly displayed over time.

  3. A C-Band Radio Frequency Interference (RFI) Detection and Mitigation Testbed, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Radio Frequency Interference (RFI) can render microwave radiometer measurements useless. We propose a method and an architecture that can be used to identify sources...

  4. Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

    International Nuclear Information System (INIS)

    Hu, M.; Bai, Y. Z.; Zhou, Z. B.; Li, Z. X.; Luo, J.

    2014-01-01

    The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided

  5. Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

    Energy Technology Data Exchange (ETDEWEB)

    Hu, M.; Bai, Y. Z., E-mail: abai@mail.hust.edu.cn; Zhou, Z. B., E-mail: zhouzb@mail.hust.edu.cn; Li, Z. X.; Luo, J. [MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-05-15

    The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided.

  6. Coronary artery calcification detected by a mobile helical CT unit in a mass screening. The frequency and relationship to coronary risk factors and coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Itani, Yasutaka; Watanabe, Shigeru; Masuda, Yoshiaki [Chiba Univ. (Japan). School of Medicine; Hanamura, Kazuhisa; Asakura, Kazuhiro; Sone, Shusuke; Sunami, Yuko; Shimura, Akimitsu; Miyamoto, Tadaaki

    2001-06-01

    A strong relationship is known to exist between coronary artery disease (CAD) and coronary artery calcification (CAC) detected by CT. In this study, we investigated the frequency of CAC and the relationship between coronary risk factors, CAD and CAC in a mass screening using a mobile helical CT unit. The total number of participants was 10008 people undergoing a medical examination for lung cancer and tuberculosis using a mobile helical CT unit. We measured the CT density of the coronary artery to detect CAC. The CT density threshold for determining CAC was above +110HU. The frequency of CAC was 16.0% in the overall patient population and significantly higher in males than in females (20.6% vs 10.7%). Frequency increased with age in both genders. Hypertension and diabetes mellitus were significantly related to CAC. Smoking showed a correlation with CAC only in males. A significant relationship was observed between CAD and CAC in males. In particular, the relationship between them was strongest in males under 60 years of age. Furthermore, the odds ratio of CAC in predicting CAD increased with increasing risk factors in both genders. (author)

  7. The simultaneous ex vivo detection of low-frequency antigen-specific CD4+ and CD8+ T-cell responses using overlapping peptide pools.

    Science.gov (United States)

    Singh, Satwinder Kaur; Meyering, Maaike; Ramwadhdoebe, Tamara H; Stynenbosch, Linda F M; Redeker, Anke; Kuppen, Peter J K; Melief, Cornelis J M; Welters, Marij J P; van der Burg, Sjoerd H

    2012-11-01

    The ability to measure antigen-specific T cells at the single-cell level by intracellular cytokine staining (ICS) is a promising immunomonitoring tool and is extensively applied in the evaluation of immunotherapy of cancer. The protocols used to detect antigen-specific CD8+ T-cell responses generally work for the detection of antigen-specific T cells in samples that have undergone at least one round of in vitro pre-stimulation. Application of a common protocol but now using long peptides as antigens was not suitable to simultaneously detect antigen-specific CD8+ and CD4+ T cells directly ex vivo in cryopreserved samples. CD8 T-cell reactivity to monocytes pulsed with long peptides as antigens ranged between 5 and 25 % of that observed against monocytes pulsed with a direct HLA class I fitting minimal CTL peptide epitope. Therefore, we adapted our ICS protocol and show that the use of tenfold higher concentration of long peptides to load APC, the use of IFN-α and poly(I:C) to promote antigen processing and improve T-cell stimulation, does allow for the ex vivo detection of low-frequency antigen-specific CD8+ and CD4+ T cells in an HLA-independent setting. While most of the improvements were related to increasing the ability to measure CD8+ T-cell reactivity following stimulation with long peptides to at least 50 % of the response detected when using a minimal peptide epitope, the final analysis of blood samples from vaccinated patients successfully showed that the adapted ICS protocol also increases the ability to ex vivo detect low-frequency p53-specific CD4+ T-cell responses in cryopreserved PBMC samples.

  8. The effects of frequency-encoding gradient upon detectability of the margins and height measurements of normal adult pituitary glands

    International Nuclear Information System (INIS)

    Taketomi, A.; Sato, N.; Aoki, J.; Endo, K.

    2004-01-01

    We investigated the effects of frequency-encoding gradient (FEG) upon detectability and height measurements of the normal adult pituitary gland. We obtained two sets of T1-weighted sagittal images of the pituitary gland from 70 adult subjects without known pituitary dysfunction using 1.5 tesla imagers; one with an inferior-superior FEG, and one with an anterior-posterior FEG. We classified the subjects into three types according to the distribution of fatty marrow in the clivus. Each set of images was assessed for pituitary height on midline sagittal images, and detectability of pituitary margins. Height measurements and detectability scores were evaluated for significant difference between the two FEGs. In subjects with fatty marrow in the clivus, there was significant difference between pituitary height measurements (P<0.005) and pituitary margin detectability (P<0.001). Care should be taken to image the pituitary gland using an anterior-posterior FEG. (orig.)

  9. A practical approach to tramway track condition monitoring: vertical track defects detection and identification using time-frequency processing technique

    Directory of Open Access Journals (Sweden)

    Bocz Péter

    2018-03-01

    Full Text Available This paper presents an automatic method for detecting vertical track irregularities on tramway operation using acceleration measurements on trams. For monitoring of tramway tracks, an unconventional measurement setup is developed, which records the data of 3-axes wireless accelerometers mounted on wheel discs. Accelerations are processed to obtain the vertical track irregularities to determine whether the track needs to be repaired. The automatic detection algorithm is based on time–frequency distribution analysis and determines the defect locations. Admissible limits (thresholds are given for detecting moderate and severe defects using statistical analysis. The method was validated on frequented tram lines in Budapest and accurately detected severe defects with a hit rate of 100%, with no false alarms. The methodology is also sensitive to moderate and small rail surface defects at the low operational speed.

  10. Single sources in the low-frequency gravitational wave sky: properties and time to detection by pulsar timing arrays

    Science.gov (United States)

    Kelley, Luke Zoltan; Blecha, Laura; Hernquist, Lars; Sesana, Alberto; Taylor, Stephen R.

    2018-06-01

    We calculate the properties, occurrence rates and detection prospects of individually resolvable `single sources' in the low-frequency gravitational wave (GW) spectrum. Our simulations use the population of galaxies and massive black hole binaries from the Illustris cosmological hydrodynamic simulations, coupled to comprehensive semi-analytic models of the binary merger process. Using mock pulsar timing arrays (PTA) with, for the first time, varying red-noise models, we calculate plausible detection prospects for GW single sources and the stochastic GW background (GWB). Contrary to previous results, we find that single sources are at least as detectable as the GW background. Using mock PTA, we find that these `foreground' sources (also `deterministic'/`continuous') are likely to be detected with ˜20 yr total observing baselines. Detection prospects, and indeed the overall properties of single sources, are only moderately sensitive to binary evolution parameters - namely eccentricity and environmental coupling, which can lead to differences of ˜5 yr in times to detection. Red noise has a stronger effect, roughly doubling the time to detection of the foreground between a white-noise only model (˜10-15 yr) and severe red noise (˜20-30 yr). The effect of red noise on the GWB is even stronger, suggesting that single source detections may be more robust. We find that typical signal-to-noise ratios for the foreground peak near f = 0.1 yr-1, and are much less sensitive to the continued addition of new pulsars to PTA.

  11. Sleep Deprivation in Young and Healthy Subjects Is More Sensitively Identified by Higher Frequencies of Electrodermal Activity than by Skin Conductance Level Evaluated in the Time Domain

    Directory of Open Access Journals (Sweden)

    Hugo F. Posada-Quintero

    2017-06-01

    Full Text Available We analyzed multiple measures of the autonomic nervous system (ANS based on electrodermal activity (EDA and heart rate variability (HRV for young healthy subjects undergoing 24-h sleep deprivation. In this study, we have utilized the error awareness test (EAT every 2 h (13 runs total, to evaluate the deterioration of performance. EAT consists of trials where the subject is presented words representing colors. Subjects are instructed to press a button (“Go” trials or withhold the response if the word presented and the color of the word mismatch (“Stroop No-Go” trial, or the screen is repeated (“Repeat No-Go” trials. We measured subjects' (N = 10 reaction time to the “Go” trials, and accuracy to the “Stroop No-Go” and “Repeat No-Go” trials. Simultaneously, changes in EDA and HRV indices were evaluated. Furthermore, the relationship between reactiveness and vigilance measures and indices of sympathetic control based on HRV were analyzed. We found the performance improved to a stable level from 6 through 16 h of deprivation, with a subsequently sustained impairment after 18 h. Indices of higher frequencies of EDA related more to vigilance measures, whereas lower frequencies index (skin conductance leve, SCL measured the reactiveness of the subject. We conclude that indices of EDA, including those of the higher frequencies, termed TVSymp, EDASymp, and NSSCRs, provide information to better understand the effect of sleep deprivation on subjects' autonomic response and performance.

  12. Robust fault detection for the dynamics of high-speed train with multi-source finite frequency interference.

    Science.gov (United States)

    Bai, Weiqi; Dong, Hairong; Yao, Xiuming; Ning, Bin

    2018-04-01

    This paper proposes a composite fault detection scheme for the dynamics of high-speed train (HST), using an unknown input observer-like (UIO-like) fault detection filter, in the presence of wind gust and operating noises which are modeled as disturbance generated by exogenous system and unknown multi-source disturbance within finite frequency domain. Using system input and system output measurements, the fault detection filter is designed to generate the needed residual signals. In order to decouple disturbance from residual signals without truncating the influence of faults, this paper proposes a method to partition the disturbance into two parts. One subset of the disturbance does not appear in residual dynamics, and the influence of the other subset is constrained by H ∞ performance index in a finite frequency domain. A set of detection subspaces are defined, and every different fault is assigned to its own detection subspace to guarantee the residual signals are diagonally affected promptly by the faults. Simulations are conducted to demonstrate the effectiveness and merits of the proposed method. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Effects of frequency and duration on psychometric functions for detection of increments and decrements in sinusoids in noise.

    Science.gov (United States)

    Moore, B C; Peters, R W; Glasberg, B R

    1999-12-01

    Psychometric functions for detecting increments or decrements in level of sinusoidal pedestals were measured for increment and decrement durations of 5, 10, 20, 50, 100, and 200 ms and for frequencies of 250, 1000, and 4000 Hz. The sinusoids were presented in background noise intended to mask spectral splatter. A three-interval, three-alternative procedure was used. The results indicated that, for increments, the detectability index d' was approximately proportional to delta I/I. For decrements, d' was approximately proportional to delta L. The slopes of the psychometric functions increased (indicating better performance) with increasing frequency for both increments and decrements. For increments, the slopes increased with increasing increment duration up to 200 ms at 250 and 1000 Hz, but at 4000 Hz they increased only up to 50 ms. For decrements, the slopes increased for durations up to 50 ms, and then remained roughly constant, for all frequencies. For a center frequency of 250 Hz, the slopes of the psychometric functions for increment detection increased with duration more rapidly than predicted by a "multiple-looks" hypothesis, i.e., more rapidly than the square root of duration, for durations up to 50 ms. For center frequencies of 1000 and 4000 Hz, the slopes increased less rapidly than predicted by a multiple-looks hypothesis, for durations greater than about 20 ms. The slopes of the psychometric functions for decrement detection increased with decrement duration at a rate slightly greater than the square root of duration, for durations up to 50 ms, at all three frequencies. For greater durations, the increase in slope was less than proportional to the square root of duration. The results were analyzed using a model incorporating a simulated auditory filter, a compressive nonlinearity, a sliding temporal integrator, and a decision device based on a template mechanism. The model took into account the effects of both the external noise and an assumed internal

  14. Detection of Second Sound in He-II for Thermal Quench Mapping of Superconducting Radio Frequency Accelerating Cavities

    CERN Document Server

    Stegmaier, Tobias; Kind, Matthias; Furci, Hernán; Koettig, Torsten; Peters, Benedikt

    The development of future particle accelerators requires intensive testing of superconducting radio frequency cavities with different sizes and geometries. Non-contact thermometry quench localisation techniques proved to be beneficial for the localisation of surface defects that can originate a quench (sudden loss of superconducting state). These techniques are based on the detection of second sound in helium II. Transition Edge Sensors (TES) are highly sensitive thin film thermometers with fast time response. In the present work, their capability as a thermal quench mapping device for superconducting radio frequency cavities is proven experimentally by detecting second sound waves emitted by SMD heaters in a He-II bath at saturated vapour pressure. A characterisation of the sensors at steady bath temperatures was conducted to calculate the thermal sensitivity. An intense metallurgical study of gold-tin TES with different compositions revealed important relations between the superconducting behaviour and the ...

  15. Detection of local birefringence in embedded fiber Bragg grating caused by concentrated transverse load using optical frequency domain reflectometry

    Science.gov (United States)

    Wada, D.; Murayama, H.; Igawa, H.

    2014-05-01

    We investigate the capability of local birefringence detection in an embedded fiber Bragg grating (FBG) using optical frequency domain reflectometry. We embed an FBG into carbon fiber reinforced plastic specimen, and conduct 3-point bending test. The cross-sectional stresses are applied to the FBG at the loading location in addition to the non-uniform longitudinal strain distribution over the length of the FBG. The local birefringence due to the cross-sectional stresses was successfully detected while the non-uniform longitudinal strain distribution was accurately measured.

  16. Comparison of low and high frequency transducers in the detection of liver metastases.

    Science.gov (United States)

    Schacherer, D; Wrede, C; Obermeier, F; Schölmerich, J; Schlottmann, K; Klebl, F

    2006-09-01

    To evaluate the benefit of the additional use of a high frequency ultrasound probe (7.5 MHz) in finding suspicious liver lesions compared to the examination using a 3.5-MHz transducer only. One hundred and fifty-seven patients with underlying malignant disease were examined with both transducers using one of three ultrasound machines (Siemens Sonoline Elegra, GE Healthcare Logic 9, or Hitachi EUB-8500). Findings on hepatic lesions were collected on a standardised documentation sheet and evaluated by descriptive statistics. Ninety-three patients (59.2% of all patients) showed no evident liver lesion on conventional ultrasound with the 3.5 MHz probe. In 29 patients (18.5%) new suspicious liver lesions were found by using the high frequency transducer. Thirteen of these 29 patients (44.8%) were suspected to suffer from diffuse infiltration of the liver with malignant lesions or at least 10 additional visible lesions. In 14 patients, no liver lesion had been known before high frequency ultrasound examination. The size of newly described liver lesions ranged from 2 mm to 1.5 cm. Time needed for the additional examination with the high frequency transducer ranged between 1 and 15 min with an average of 4.0 min. The additional use of a high frequency transducer in patients with underlying malignant disease slightly extends the examination time, but reveals new, potentially malignant hepatic lesions in almost every fifth patient.

  17. Damage detection in multi-span beams based on the analysis of frequency changes

    International Nuclear Information System (INIS)

    Gillich, G R; Ntakpe, J L; Praisach, Z I; Mimis, M C; Abdel Wahab, M

    2017-01-01

    Crack identification in multi-span beams is performed to determine whether the structure is healthy or not. Among all crack identification methods, these based on measured natural frequency changes present the advantage of simplicity and easy to use in practical engineering. To accurately identify the cracks characteristics for multi-span beam structure, a mathematical model is established, which can predict frequency changes for any boundary conditions, the intermediate supports being hinges. This relation is based on the modal strain energy concept. Since frequency changes are relative small, to obtain natural frequencies with high resolution, a signal processing algorithm based on superposing of numerous spectra is also proposed, which overcomes the disadvantage of Fast Fourier Transform in the aspect of frequency resolution. Based on above-mentioned mathematical model and signal processing algorithm, the method of identifying cracks on multi-span beams is presented. To verify the accuracy of this identification method, experimental examples are conducted on a two-span structure. The results demonstrate that the method proposed in this paper can accurately identify the crack position and depth. (paper)

  18. Detection of Second Sound in He-II for Thermal Quench Mapping of Superconducting Radio Frequency Accelerating Cavities

    OpenAIRE

    Stegmaier, Tobias; Grohmann, Steffen; Kind, Matthias; Furci, Hernán; Koettig, Torsten; Peters, Benedikt

    2018-01-01

    The development of future particle accelerators requires intensive testing of superconducting radio frequency cavities with different sizes and geometries. Non-contact thermometry quench localisation techniques proved to be beneficial for the localisation of surface defects that can originate a quench (sudden loss of superconducting state). These techniques are based on the detection of second sound in helium II. Transition Edge Sensors (TES) are highly sensitive thin film thermometers with f...

  19. Assessment of Crack Detection in Heavy-Walled Cast Stainless Steel Piping Welds Using Advanced Low-Frequency Ultrasonic Methods

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Michael T.; Crawford, Susan L.; Cumblidge, Stephen E.; Denslow, Kayte M.; Diaz, Aaron A.; Doctor, Steven R.

    2007-03-01

    Studies conducted at the Pacific Northwest National Laboratory in Richland, Washington, have focused on assessing the effectiveness and reliability of novel approaches to nondestructive examination (NDE) for inspecting coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the U.S. Nuclear Regulatory Commission on the effectiveness and reliability of advanced NDE methods as related to the inservice inspection of safety-related components in pressurized water reactors (PWRs). This report provides progress, recent developments, and results from an assessment of low frequency ultrasonic testing (UT) for detection of inside surface-breaking cracks in cast stainless steel reactor piping weldments as applied from the outside surface of the components. Vintage centrifugally cast stainless steel piping segments were examined to assess the capability of low-frequency UT to adequately penetrate challenging microstructures and determine acoustic propagation limitations or conditions that may interfere with reliable flaw detection. In addition, welded specimens containing mechanical and thermal fatigue cracks were examined. The specimens were fabricated using vintage centrifugally cast and statically cast stainless steel materials, which are typical of configurations installed in PWR primary coolant circuits. Ultrasonic studies on the vintage centrifugally cast stainless steel piping segments were conducted with a 400-kHz synthetic aperture focusing technique and phased array technology applied at 500 kHz, 750 kHz, and 1.0 MHz. Flaw detection and characterization on the welded specimens was performed with the phased array method operating at the frequencies stated above. This report documents the methodologies used and provides results from laboratory studies to assess baseline material noise, crack detection, and length-sizing capability for low-frequency UT in cast stainless steel piping.

  20. Selection of mother wavelets for the detection of the oscillation frequencies in power signals of nuclear reactors

    International Nuclear Information System (INIS)

    Amador G, R.; Castillo D, R.; Ortiz V, J.

    2007-01-01

    Diverse types of transitory events can lead to oscillations of power in nuclear reactors. In such events, the power monitors provide a signal that contains important characteristics of the transitory one, as the oscillation frequency, tendencies, changes and the instants or periods in those that important events are presented. This characteristics are detected by means of diverse analysis techniques, as Autoregressive methods, Fourier Transform, Fourier Transform in Short Time, Wavelets Transform, among others. Presently work is used the one Wavelets Continuous Transform because it allows to carry out studies of the stationary, quasi-stationary and transitory signals in the Time-scale and Time-scale-spectrum planes. Contrary to other similar works, this work describes a methodology for the selection of the scales and the Wavelet mother to be applied the one Wavelets Continuous Transform, with the objective of detecting to the dominant frequencies of the system. To prove the proposal a broadly well-known real signal of an event of power oscillations it has been used. The obtained results correspond to three families of Wavelets mothers that fulfilled the conditions of scales and central frequency of the proposal. The results show that the value of the certain frequency oscillation in this work is practically the same one reported in other studies with other techniques. (Author)

  1. Stretchable Complementary Split Ring Resonator (CSRR-Based Radio Frequency (RF Sensor for Strain Direction and Level Detection

    Directory of Open Access Journals (Sweden)

    Seunghyun Eom

    2016-10-01

    Full Text Available In this paper, we proposed a stretchable radio frequency (RF sensor to detect strain direction and level. The stretchable sensor is composed of two complementary split ring resonators (CSRR with microfluidic channels. In order to achieve stretchability, liquid metal (eutectic gallium-indium, EGaIn and Ecoflex substrate are used. Microfluidic channels are built by Ecoflex elastomer and microfluidic channel frames. A three-dimensional (3D printer is used for fabrication of microfluidic channel frames. Two CSRR resonators are designed to resonate 2.03 GHz and 3.68 GHz. When the proposed sensor is stretched from 0 to 8 mm along the +x direction, the resonant frequency is shifted from 3.68 GHz to 3.13 GHz. When the proposed sensor is stretched from 0 to 8 mm along the −x direction, the resonant frequency is shifted from 2.03 GHz to 1.78 GHz. Therefore, we can detect stretched length and direction from independent variation of two resonant frequencies.

  2. Comparison of spatial frequency domain features for the detection of side attack explosive ballistics in synthetic aperture acoustics

    Science.gov (United States)

    Dowdy, Josh; Anderson, Derek T.; Luke, Robert H.; Ball, John E.; Keller, James M.; Havens, Timothy C.

    2016-05-01

    Explosive hazards in current and former conflict zones are a threat to both military and civilian personnel. As a result, much effort has been dedicated to identifying automated algorithms and systems to detect these threats. However, robust detection is complicated due to factors like the varied composition and anatomy of such hazards. In order to solve this challenge, a number of platforms (vehicle-based, handheld, etc.) and sensors (infrared, ground penetrating radar, acoustics, etc.) are being explored. In this article, we investigate the detection of side attack explosive ballistics via a vehicle-mounted acoustic sensor. In particular, we explore three acoustic features, one in the time domain and two on synthetic aperture acoustic (SAA) beamformed imagery. The idea is to exploit the varying acoustic frequency profile of a target due to its unique geometry and material composition with respect to different viewing angles. The first two features build their angle specific frequency information using a highly constrained subset of the signal data and the last feature builds its frequency profile using all available signal data for a given region of interest (centered on the candidate target location). Performance is assessed in the context of receiver operating characteristic (ROC) curves on cross-validation experiments for data collected at a U.S. Army test site on different days with multiple target types and clutter. Our preliminary results are encouraging and indicate that the top performing feature is the unrolled two dimensional discrete Fourier transform (DFT) of SAA beamformed imagery.

  3. Early Detection of Atrophy of Foot Muscles in Chinese Patients of Type 2 Diabetes Mellitus by High-Frequency Ultrasonography

    Directory of Open Access Journals (Sweden)

    Xiaohui Wang

    2014-01-01

    Full Text Available The aim of this study was to evaluate the diagnostic value of high-frequency ultrasonography in detecting atrophy of foot muscles in Chinese patients of type 2 diabetes mellitus (T2DM. Chinese patients of T2DM with (n=56 or without (n=50 diabetic peripheral neuropathy (DPN and the control subjects (n=50 were enrolled. The nondominant foot of all subjects was examined with high-frequency ultrasonography. The transverse diameter, thickness, and cross-sectional area of the extensor digitorum brevis muscle (EDB and the thickness of the muscles of the first interstitium (MILs were measured. The results showed that the ultrasonographic transverse diameter, thickness, and cross-sectional area of EDB and the thickness of MILs in patients of T2DM with DPN were significantly smaller than those in patients of T2DM without DPN (all P<0.01 and those in the control subjects (all P<0.01. The transverse diameter and cross-sectional area of the EDB and thickness of MILs in patients of T2DM without DPN were significantly smaller than those of the control subjects (all P<0.01. In conclusion, the atrophy of foot muscle in Chinese T2DM patients can be detected by high-frequency ultrasonography. Notably, ultrasonography may detect early atrophy of foot muscles in patients without DPN.

  4. Radio Frequency Interference Detection and Mitigation Techniques Using Data from Ecosar 2014 Flight Campaign

    Science.gov (United States)

    Osmanoglu, Batuhan; Rincon, Rafael F.; Lee, SeungKuk; Fatoyinb, Temilola; Bollian, Tobias

    2016-01-01

    Radio frequency interference (RFI) has strong influence on wide band airborne radar systems, especially operaingat L-band (1-2 GHz) or lower frequencies. EcoSAR is a P-band digital beamforming radar system, and RFI has tobe removed from raw echoes to obtain science quality data. In this paper we describe the current methodologyused to tackle RFI with EcoSAR, and provide an example on its performance. Finally, we discuss the advantagesand disadvantages of the method and mention potential improvements.

  5. Detection of optic nerve lesions in optic neuritis using frequency-selective fat-saturation sequences

    International Nuclear Information System (INIS)

    Miller, D.H.; MacManus, D.G.; Bartlett, P.A.; Kapoor, R.; Morrissey, S.P.; Moseley, I.F.

    1993-01-01

    MRI was performed on seven patients with acute optic neuritis, using two sequences which suppress the signal from orbital fat: frequency-selective fat-saturation and inversion recovery with a short inversion time. Lesions were seen on both sequences in all the symptomatic optic nerves studied. (orig.)

  6. Implicit versus Explicit Frequency Comparisons: Two Mechanisms of Auditory Change Detection

    Science.gov (United States)

    Demany, Laurent; Semal, Catherine; Pressnitzer, Daniel

    2011-01-01

    Listeners had to compare, with respect to pitch (frequency), a pure tone (T) to a combination of pure tones presented subsequently (C). The elements of C were either synchronous, and therefore difficult to hear out individually, or asynchronous and therefore easier to hear out individually. In the "present/absent" condition, listeners had to judge…

  7. Experiments with a Ship-Mounted Low Frequency SAS for the Detection of Buried Objects

    NARCIS (Netherlands)

    Colin, M.E.G.D.; Quesson, B.A.J.; Hetet, A.; Groen, J.; Sabel, J.C.; Zerr, B.; Brusieux, M.; Legris, M.

    2004-01-01

    In September 2002, GESMA and TNO-FEL carried out a sea trial with a low frequency (20 kHz) sonar mounted on a mine hunter. The objective of the experiments was to collect sonar echoes from proud and buried objects for subsequent synthetic aperture processing. A large data set was collected,

  8. Identification and Level 1 Damage Detection of the Z24 Highway Bridge by Frequency Domain Decomposition

    DEFF Research Database (Denmark)

    Brincker, Rune; Andersen, P.; Cantieni, R.

    2001-01-01

    A series of 15 progressive damage tests were performed on a prestressed concrete highway bridge in Switzerland. The ambient response of the bridge was recorded for each damage case with a relatively large number of sensors. Changes in frequencies, damping ratios and MAC values were determined...

  9. High frequency microphone measurements for transition detection on airfoils. NACA-0015 appendix report

    DEFF Research Database (Denmark)

    Døssing, Mads

    Time series of pressure fluctuations has been obtained using high frequency microphones distributed over the surface of airfoils undergoing wind tunnel tests in the LM Windtunnel, owned by ’LM Glasfiber’, Denmark. The present report describes the dataanalysis, with special attention given to tran...

  10. Using high-frequency sampling to detect effects of atmospheric pollutants on stream chemistry

    Science.gov (United States)

    Stephen D. Sebestyen; James B. Shanley; Elizabeth W. Boyer

    2009-01-01

    We combined information from long-term (weekly over many years) and short-term (high-frequency during rainfall and snowmelt events) stream water sampling efforts to understand how atmospheric deposition affects stream chemistry. Water samples were collected at the Sleepers River Research Watershed, VT, a temperate upland forest site that receives elevated atmospheric...

  11. A hybrid polarization-selective atomic sensor for radio-frequency field detection with a passive resonant-cavity field amplifier

    OpenAIRE

    Anderson, David A.; Paradis, Eric G.; Raithel, Georg

    2018-01-01

    We present a hybrid atomic sensor that realizes radio-frequency electric field detection with intrinsic field amplification and polarization selectivity for robust high-sensitivity field measurement. The hybrid sensor incorporates a passive resonator element integrated with an atomic vapor cell that provides amplification and polarization selectivity for detection of incident radio-frequency fields. The amplified intra-cavity radio-frequency field is measured by atoms using a quantum-optical ...

  12. Stepped Frequency GPR for Utility Line Detection using Polarization Dependent Scattering

    DEFF Research Database (Denmark)

    Jensen, Ole Kiel; Gregersen, Ole

    2000-01-01

    A GPR for detection of buried cables and pipes is developed by Ekko Dome Production in cooperation with Aalborg University. The appearance is a "lawn mower" model including antennas, electronics and on-line data processing. A successful result is obtained by combining dedicated hardware and signa...... conditions, including sand, wet clay, pavements and grass covered soil. The results show reliable detection even when the conditions are difficult....

  13. An iterative detection method of MIMO over spatial correlated frequency selective channel: using list sphere decoding for simplification

    Science.gov (United States)

    Shi, Zhiping; Yan, Bing

    2010-08-01

    In multiple-input multiple-output(MIMO) wireless systems, combining good channel codes(e.g., Non-binary Repeat Accumulate codes) with adaptive turbo equalization is a good option to get better performance and lower complexity under Spatial Correlated Frequency Selective(SCFS) Channel. The key of this method is after joint antennas MMSE detection (JAD/MMSE) based on interruption cancelling using soft information, considering the detection result as an output of a Gaussian equivalent flat fading channel, and performing maximum likelihood detection(ML) to get more correct estimated result. But the using of ML brings great complexity increase, which is not allowed. In this paper, a low complexity method called list sphere decoding is introduced and applied to replace the ML in order to simplify the adaptive iterative turbo equalization system.

  14. Selective detection of crystalline cellulose in plant cell walls with sum-frequency-generation (SFG) vibration spectroscopy.

    Science.gov (United States)

    Barnette, Anna L; Bradley, Laura C; Veres, Brandon D; Schreiner, Edward P; Park, Yong Bum; Park, Junyeong; Park, Sunkyu; Kim, Seong H

    2011-07-11

    The selective detection of crystalline cellulose in biomass was demonstrated with sum-frequency-generation (SFG) vibration spectroscopy. SFG is a second-order nonlinear optical response from a system where the optical centrosymmetry is broken. In secondary plant cell walls that contain mostly cellulose, hemicellulose, and lignin with varying concentrations, only certain vibration modes in the crystalline cellulose structure can meet the noninversion symmetry requirements. Thus, SFG can be used to detect and analyze crystalline cellulose selectively in lignocellulosic biomass without extraction of noncellulosic species from biomass or deconvolution of amorphous spectra. The selective detection of crystalline cellulose in lignocellulosic biomass is not readily achievable with other techniques such as XRD, solid-state NMR, IR, and Raman analyses. Therefore, the SFG analysis presents a unique opportunity to reveal the cellulose crystalline structure in lignocellulosic biomass.

  15. The Relative Importance of Random Error and Observation Frequency in Detecting Trends in Upper Tropospheric Water Vapor

    Science.gov (United States)

    Whiteman, David N.; Vermeesch, Kevin C.; Oman, Luke D.; Weatherhead, Elizabeth C.

    2011-01-01

    Recent published work assessed the amount of time to detect trends in atmospheric water vapor over the coming century. We address the same question and conclude that under the most optimistic scenarios and assuming perfect data (i.e., observations with no measurement uncertainty) the time to detect trends will be at least 12 years at approximately 200 hPa in the upper troposphere. Our times to detect trends are therefore shorter than those recently reported and this difference is affected by data sources used, method of processing the data, geographic location and pressure level in the atmosphere where the analyses were performed. We then consider the question of how instrumental uncertainty plays into the assessment of time to detect trends. We conclude that due to the high natural variability in atmospheric water vapor, the amount of time to detect trends in the upper troposphere is relatively insensitive to instrumental random uncertainty and that it is much more important to increase the frequency of measurement than to decrease the random error in the measurement. This is put in the context of international networks such as the Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) and the Network for the Detection of Atmospheric Composition Change (NDACC) that are tasked with developing time series of climate quality water vapor data.

  16. High-resolution broadband terahertz spectroscopy via electronic heterodyne detection of photonically generated terahertz frequency comb.

    Science.gov (United States)

    Pavelyev, D G; Skryl, A S; Bakunov, M I

    2014-10-01

    We report an alternative approach to the terahertz frequency-comb spectroscopy (TFCS) based on nonlinear mixing of a photonically generated terahertz pulse train with a continuous wave signal from an electronic synthesizer. A superlattice is used as a nonlinear mixer. Unlike the standard TFCS technique, this approach does not require a complex double-laser system but retains the advantages of TFCS-high spectral resolution and wide bandwidth.

  17. Intracerebrally recorded high frequency oscillations: Simple visual assessment versus automated detection

    Czech Academy of Sciences Publication Activity Database

    Pail, M.; Halámek, Josef; Daniel, P.; Kuba, R.; Tyrlíková, I.; Chrastina, J.; Jurák, Pavel; Rektor, I.; Brázdil, M.

    2013-01-01

    Roč. 124, č. 10 (2013), s. 1935-1942 ISSN 1388-2457 R&D Projects: GA ČR GAP103/11/0933; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : High frequency oscillations * Spikes * Ripples * Temporal lobe epilepsy * Extratemporal lobe epilepsy * Seizure onset zone * Epileptogenic zone Subject RIV: FH - Neurology Impact factor: 2.979, year: 2013

  18. Detection and frequency of recombination in tomato-infecting begomoviruses of South and Southeast Asia

    Directory of Open Access Journals (Sweden)

    Rai Mathura

    2007-10-01

    Full Text Available Abstract Background Tomato-infecting begomoviruses are widely distributed across the world and cause diseases of high economic impact on wide range of agriculturally important crops. Though recombination plays a pivotal role in diversification and evolution of these viruses, it is currently unknown whether there are differences in the number and quality of recombination events amongst different tomato-infecting begomovirus species. To examine this we sought to characterize the recombination events, estimate the frequency of recombination, and map recombination hotspots in tomato-infecting begomoviruses of South and Southeast Asia. Results Different methods used for recombination breakpoint analysis provided strong evidence for presence of recombination events in majority of the sequences analyzed. However, there was a clear evidence for absence or low Recombination events in viruses reported from North India. In addition, we provide evidence for non-random distribution of recombination events with the highest frequency of recombination being mapped in the portion of the N-terminal portion of Rep. Conclusion The variable recombination observed in these viruses signified that all begomoviruses are not equally prone to recombination. Distribution of recombination hotspots was found to be reliant on the relatedness of the genomic region involved in the exchange. Overall the frequency of phylogenetic violations and number of recombination events decreased with increasing parental sequence diversity. These findings provide valuable new information for understanding the diversity and evolution of tomato-infecting begomoviruses in Asia.

  19. 3D versus 2D Systematic Transrectal Ultrasound-Guided Prostate Biopsy: Higher Cancer Detection Rate in Clinical Practice

    Directory of Open Access Journals (Sweden)

    Alexandre Peltier

    2013-01-01

    Full Text Available Objectives. To compare prostate cancer detection rates of extended 2D versus 3D biopsies and to further assess the clinical impact of this method in day-to-day practice. Methods. We analyzed the data of a cohort of 220 consecutive patients with no prior history of prostate cancer who underwent an initial prostate biopsy in daily practice due to an abnormal PSA and/or DRE using, respectively, the classical 2D and the new 3D systems. All the biopsies were done by a single experienced operator using the same standardized protocol. Results. There was no significant difference in terms of age, total PSA, or prostate volume between the two groups. However, cancer detection rate was significantly higher using the 3D versus the 2D system, 50% versus 34% (P<0.05. There was no statistically significant difference while comparing the 2 groups in term of nonsignificant cancer detection. Conclusion. There is reasonable evidence demonstrating the superiority of the 3D-guided biopsies in detecting prostate cancers that would have been missed using the 2D extended protocol.

  20. Females with paired occurrence of cancers in the UADT and genital region have a higher frequency of either Glutathione S-transferase M1/T1 null genotype

    Directory of Open Access Journals (Sweden)

    Jhavar Sameer G

    2005-03-01

    Full Text Available Abstract Upper Aero digestive Tract (UADT is the commonest site for the development of second cancer in females after primary cervical cancer. Glutathione S-transferase (GSTM1 and / or T1 null genotype modulates the risk of developing UADT cancer (primary as well as second cancer. The aim of this study was to evaluate the difference in GST null genotype frequencies in females with paired cancers in the UADT and genital region as compared to females with paired cancers in the UADT and non-genital region. Forty-nine females with a cancer in the UADT and another cancer (at all sites-genital and non-genital were identified from a database of patients with multiple primary neoplasms and were analyzed for the GSTM1 and T1 genotype in addition to known factors such as age, tobacco habits, alcohol habits and family history of cancer. Frequencies of GSTM1 null, GSTT1 null, and either GSTM1/T1 null were higher in females with paired occurrence of cancer in the UADT and genital site (54%, 33% and 75% respectively in comparison to females with paired occurrence of cancer in the UADT and non-genital sites (22%, 6% and 24% respectively. The significantly higher inherited frequency of either GSTM1/T1 null genotype in females with a paired occurrence of cancers in UADT and genital region (p = 0.01, suggests that these females are more susceptible to damage by carcinogens as compared to females who have UADT cancers in association with cancers at non-genital sites.

  1. Modeling panel detection frequencies by queuing system theory: an application in gas chromatography olfactometry.

    Science.gov (United States)

    Bult, Johannes H F; van Putten, Bram; Schifferstein, Hendrik N J; Roozen, Jacques P; Voragen, Alphons G J; Kroeze, Jan H A

    2004-10-01

    In continuous vigilance tasks, the number of coincident panel responses to stimuli provides an index of stimulus detectability. To determine whether this number is due to chance, panel noise levels have been approximated by the maximum coincidence level obtained in stimulus-free conditions. This study proposes an alternative method by which to assess noise levels, derived from queuing system theory (QST). Instead of critical coincidence levels, QST modeling estimates the duration of coinciding responses in the absence of stimuli. The proposed method has the advantage over previous approaches that it yields more reliable noise estimates and allows for statistical testing. The method was applied in an olfactory detection experiment using 16 panelists in stimulus-present and stimulus-free conditions. We propose that QST may be used as an alternative to signal detection theory for analyzing data from continuous vigilance tasks.

  2. Development and Testing of a Multiple Frequency Continuous Wave Radar for Target Detection and Classification

    Science.gov (United States)

    2007-03-01

    1 2’ VIH " 1 ’ 󈧏) (34) where is the modified Bessel function of zero order. Here is the conditional variance and is the conditional probability...10, the probability of detection is the area under the signal-plus-noise curve above the detection threshold co M vF (V 2+ A2)]10 ( vAPd= fnp~ju,( vIH ...Spectrogram O /STFT < 12 +J F Q’I " ’ " ""-’"’" -STFT TFRgram 2I1+ IST 21 U- •’j -/STFT,, I HP STFT ISTFTI Figure 19. 3FCW radar processing prior to

  3. Excitation of higher radial modes of azimuthal surface waves in the electron cyclotron frequency range by rotating relativistic flow of electrons in cylindrical waveguides partially filled by plasmas

    Science.gov (United States)

    Girka, Igor O.; Pavlenko, Ivan V.; Thumm, Manfred

    2018-05-01

    Azimuthal surface waves are electromagnetic eigenwaves of cylindrical plasma-dielectric waveguides which propagate azimuthally nearby the plasma-dielectric interface across an axial external stationary magnetic field. Their eigenfrequency in particular can belong to the electron cyclotron frequency range. Excitation of azimuthal surface waves by rotating relativistic electron flows was studied in detail recently in the case of the zeroth radial mode for which the waves' radial phase change within the layer where the electrons gyrate is small. In this case, just the plasma parameters cause the main influence on the waves' dispersion properties. In the case of the first and higher radial modes, the wave eigenfrequency is higher and the wavelength is shorter than in the case of the zeroth radial mode. This gain being of interest for practical applications can be achieved without any change in the device design. The possibility of effective excitation of the higher order radial modes of azimuthal surface waves is demonstrated here. Getting shorter wavelengths of the excited waves in the case of higher radial modes is shown to be accompanied by decreasing growth rates of the waves. The results obtained here are of interest for developing new sources of electromagnetic radiation, in nano-physics and in medical physics.

  4. Spatial frequency characteristics at image decision-point locations for observers with different radiological backgrounds in lung nodule detection

    Science.gov (United States)

    Pietrzyk, Mariusz W.; Manning, David J.; Dix, Alan; Donovan, Tim

    2009-02-01

    Aim: The goal of the study is to determine the spatial frequency characteristics at locations in the image of overt and covert observers' decisions and find out if there are any similarities in different observers' groups: the same radiological experience group or the same accuracy scored level. Background: The radiological task is described as a visual searching decision making procedure involving visual perception and cognitive processing. Humans perceive the world through a number of spatial frequency channels, each sensitive to visual information carried by different spatial frequency ranges and orientations. Recent studies have shown that particular physical properties of local and global image-based elements are correlated with the performance and the level of experience of human observers in breast cancer and lung nodule detections. Neurological findings in visual perception were an inspiration for wavelet applications in vision research because the methodology tries to mimic the brain processing algorithms. Methods: The wavelet approach to the set of postero-anterior chest radiographs analysis has been used to characterize perceptual preferences observers with different levels of experience in the radiological task. Psychophysical methodology has been applied to track eye movements over the image, where particular ROIs related to the observers' fixation clusters has been analysed in the spaces frame by Daubechies functions. Results: Significance differences have been found between the spatial frequency characteristics at the location of different decisions.

  5. On the performance of joint iterative detection and decoding in coherent optical channels with laser frequency fluctuations

    Science.gov (United States)

    Castrillón, Mario A.; Morero, Damián A.; Agazzi, Oscar E.; Hueda, Mario R.

    2015-08-01

    The joint iterative detection and decoding (JIDD) technique has been proposed by Barbieri et al. (2007) with the objective of compensating the time-varying phase noise and constant frequency offset experienced in satellite communication systems. The application of JIDD to optical coherent receivers in the presence of laser frequency fluctuations has not been reported in prior literature. Laser frequency fluctuations are caused by mechanical vibrations, power supply noise, and other mechanisms. They significantly degrade the performance of the carrier phase estimator in high-speed intradyne coherent optical receivers. This work investigates the performance of the JIDD algorithm in multi-gigabit optical coherent receivers. We present simulation results of bit error rate (BER) for non-differential polarization division multiplexing (PDM)-16QAM modulation in a 200 Gb/s coherent optical system that includes an LDPC code with 20% overhead and net coding gain of 11.3 dB at BER = 10-15. Our study shows that JIDD with a pilot rate ⩽ 5 % compensates for both laser phase noise and laser frequency fluctuation. Furthermore, since JIDD is used with non-differential modulation formats, we find that gains in excess of 1 dB can be achieved over existing solutions based on an explicit carrier phase estimator with differential modulation. The impact of the fiber nonlinearities in dense wavelength division multiplexing (DWDM) systems is also investigated. Our results demonstrate that JIDD is an excellent candidate for application in next generation high-speed optical coherent receivers.

  6. Efficient and Robust Detection of GFSK Signals under Dispersive Channel, Modulation Index, and Carrier Frequency Offset Conditions

    Directory of Open Access Journals (Sweden)

    Stephan Weiss

    2005-09-01

    Full Text Available Gaussian frequency shift keying is the modulation scheme specified for Bluetooth. Signal adversities typical in Bluetooth networks include AWGN, multipath propagation, carrier frequency, and modulation index offsets. In our effort to realise a robust but efficient Bluetooth receiver, we adopt a high-performance matched-filter-based detector, which is near optimal in AWGN, but requires a prohibitively costly filter bank for processing of K bits worth of the received signal. However, through filtering over a single bit period and performing phase propagation of intermediate results over successive single-bit stages, we eliminate redundancy involved in providing the matched filter outputs and reduce its complexity by up to 90% (for K=9. The constant modulus signal characteristic and the potential for carrier frequency offsets make the constant modulus algorithm (CMA suitable for channel equalisation, and we demonstrate its effectiveness in this paper. We also introduce a stochastic gradient-based algorithm for carrier frequency offset correction, and show that the relative rotation between successive intermediate filter outputs enables us to detect and correct offsets in modulation index.

  7. Towards Real-Time Detection of Gait Events on Different Terrains Using Time-Frequency Analysis and Peak Heuristics Algorithm.

    Science.gov (United States)

    Zhou, Hui; Ji, Ning; Samuel, Oluwarotimi Williams; Cao, Yafei; Zhao, Zheyi; Chen, Shixiong; Li, Guanglin

    2016-10-01

    Real-time detection of gait events can be applied as a reliable input to control drop foot correction devices and lower-limb prostheses. Among the different sensors used to acquire the signals associated with walking for gait event detection, the accelerometer is considered as a preferable sensor due to its convenience of use, small size, low cost, reliability, and low power consumption. Based on the acceleration signals, different algorithms have been proposed to detect toe off (TO) and heel strike (HS) gait events in previous studies. While these algorithms could achieve a relatively reasonable performance in gait event detection, they suffer from limitations such as poor real-time performance and are less reliable in the cases of up stair and down stair terrains. In this study, a new algorithm is proposed to detect the gait events on three walking terrains in real-time based on the analysis of acceleration jerk signals with a time-frequency method to obtain gait parameters, and then the determination of the peaks of jerk signals using peak heuristics. The performance of the newly proposed algorithm was evaluated with eight healthy subjects when they were walking on level ground, up stairs, and down stairs. Our experimental results showed that the mean F1 scores of the proposed algorithm were above 0.98 for HS event detection and 0.95 for TO event detection on the three terrains. This indicates that the current algorithm would be robust and accurate for gait event detection on different terrains. Findings from the current study suggest that the proposed method may be a preferable option in some applications such as drop foot correction devices and leg prostheses.

  8. Is interstellar detection of higher members of the linear radicals CnCH and CnN feasible?

    Science.gov (United States)

    Pauzat, F.; Ellinger, Y.; Mclean, A. D.

    1991-01-01

    Rotational constants and dipole moments for linear-chain radicals CnCH and CnN are estimated using a combinatiaon of ab initio molecular orbital calculations and observed data on the starting members of the series. CnCH with n = 0-5 have been observed by radioastronomy in carbon-rich interstellar clouds; higher members of the series have 2Pi ground states with large dipole moments and are strong candidates for observation. CN and C3N have also been observed by radioastronomy; higher members of the series, with the possible exception of C5N, have 2Pi ground states with near-zero dipole moments making their interstellar detection hopeless under present observational conditions. C5N can be a strong candidate only if it has a 2Sigma ground state, and best computations so far indicate that this is not the case.

  9. Is interstellar detection of higher members of the linear radicals CnCH and CnN feasible?

    International Nuclear Information System (INIS)

    Pauzat, F.; Ellinger, Y.; Mclean, A.D.

    1991-01-01

    Rotational constants and dipole moments for linear-chain radicals CnCH and CnN are estimated using a combinatiaon of ab initio molecular orbital calculations and observed data on the starting members of the series. CnCH with n = 0-5 have been observed by radioastronomy in carbon-rich interstellar clouds; higher members of the series have 2Pi ground states with large dipole moments and are strong candidates for observation. CN and C3N have also been observed by radioastronomy; higher members of the series, with the possible exception of C5N, have 2Pi ground states with near-zero dipole moments making their interstellar detection hopeless under present observational conditions. C5N can be a strong candidate only if it has a 2Sigma ground state, and best computations so far indicate that this is not the case. 20 refs

  10. Early Detection of Amyotrophic Lateral Sclerosis (ALS using the Gait Motor Signal Frequency Analysis

    Directory of Open Access Journals (Sweden)

    Behzad Abedi

    2016-06-01

    Full Text Available Abstract Background: ALS is a progressive neuro-muscular disease, which is characterized by motor neuron loss in the Central Nervous System (CNS and Peripheral Nervous System (PNS. Up to now, no accurate clinical method for diagnosis of the disease have been provided. In most cases, ALS patients are unable to walk normally due to abnormalities in the nervous system. For this reason, one of the most appropriate methods in the diagnosis of ALS from other neurological diseases or from healthy volunteers is the gait motor signal analysis. Materials and Methods: In this study, gait signals available in Physionet database have been used. The database consists of 13 patients with ALS (ALS1, ALS2, …, ALS13 and 16 normal subjects (CO1, CO2, …, CO16. The patients participating in this study had no history of any psychiatric disorders and did not use any assistive device for walking, like wheelchair. The power spectrum of stride, swing, and stance of normal subjects and patients was computed for both left and right legs. To provide appropriate inputs for the classifier, the frequency band of the power spectrum of all signals was divided into eight equal parts. The area of all regions was computed. Three frequency band of the lower range of power spectra selected as inputs of the classifier. Results: In this study, power spectra, as frequency attributes, were used to explore probable differences of time series in both patients and healthy subjects. Conclusion: Artificial Neural Network was used to classify normal and ALS groups with the accuracy of 83% for the test data set. It seems that the present algorithm can be used in discriminating patients from normal subjects in the early stages of the disease.

  11. Modeling of Buried Wire Detection by Radio-Frequency Electromagnetic Waves

    NARCIS (Netherlands)

    Naus, H.W.L.

    2013-01-01

    The detection of buried insulated wires of finite length with a transmitter–receiver electromagnetic induction sensor is theoretically investigated. The transmitter is modeled as a magnetic dipole. Its electric field induces a current in the cable. Analytical results for its Fourier transform are

  12. Effects of the interstellar medium on detection of low-frequency gravitational waves

    International Nuclear Information System (INIS)

    Stinebring, Dan

    2013-01-01

    Time variable delays due to radio wave propagation in the ionized interstellar medium are a substantial source of error in pulsar timing array efforts. We describe the physical origin of these effects, discussing dispersive and scattering effects separately. Where possible, we give estimates of the magnitude of timing errors produced by these effects and their scaling with radio frequency. Although there is general understanding of the interstellar medium propagation errors to be expected with pulsar timing array observations, detailed comparison between theory and practice is still in its infancy, particularly with regard to scattering effects. (paper)

  13. Atoms as nonlinear mixers for detection of quantum correlations at ultrahigh frequencies

    International Nuclear Information System (INIS)

    Georgiades, N.P.; Polzik, E.S.; Kimble, H.J.

    1997-01-01

    Measurements of quantum correlations are reported for a frequency difference of 25 THz between the signal and idler output fields generated by a subthreshold nondegenerate optical parametric oscillator. By simultaneously exciting a two-photon transition in atomic Cs by a combination of signal, idler, and open-quotes references oscillatorclose quotes fields, we record modulation of the excited-state population due to quantum interference between two alternative excitation pathways. The observed phase-sensitive modulation is proportional to the correlation function left-angle E s E i right-angle for the quantized signal and idler fields. copyright 1997 The American Physical Society

  14. Hail frequency estimation across Europe based on a combination of overshooting top detections and the ERA-INTERIM reanalysis

    Science.gov (United States)

    Punge, H. J.; Bedka, K. M.; Kunz, M.; Reinbold, A.

    2017-12-01

    This article presents a hail frequency estimation based on the detection of cold overshooting cloud tops (OTs) from the Meteosat Second Generation (MSG) operational weather satellites, in combination with a hail-specific filter derived from the ERA-INTERIM reanalysis. This filter has been designed based on the atmospheric properties in the vicinity of hail reports registered in the European Severe Weather Database (ESWD). These include Convective Available Potential Energy (CAPE), 0-6-km bulk wind shear and freezing level height, evaluated at the nearest time step and interpolated from the reanalysis grid to the location of the hail report. Regions highly exposed to hail events include Northern Italy, followed by South-Eastern Austria and Eastern Spain. Pronounced hail frequency is also found in large parts of Eastern Europe, around the Alps, the Czech Republic, Southern Germany, Southern and Eastern France, and in the Iberic and Apennine mountain ranges.

  15. A stationary wavelet transform and a time-frequency based spike detection algorithm for extracellular recorded data.

    Science.gov (United States)

    Lieb, Florian; Stark, Hans-Georg; Thielemann, Christiane

    2017-06-01

    Spike detection from extracellular recordings is a crucial preprocessing step when analyzing neuronal activity. The decision whether a specific part of the signal is a spike or not is important for any kind of other subsequent preprocessing steps, like spike sorting or burst detection in order to reduce the classification of erroneously identified spikes. Many spike detection algorithms have already been suggested, all working reasonably well whenever the signal-to-noise ratio is large enough. When the noise level is high, however, these algorithms have a poor performance. In this paper we present two new spike detection algorithms. The first is based on a stationary wavelet energy operator and the second is based on the time-frequency representation of spikes. Both algorithms are more reliable than all of the most commonly used methods. The performance of the algorithms is confirmed by using simulated data, resembling original data recorded from cortical neurons with multielectrode arrays. In order to demonstrate that the performance of the algorithms is not restricted to only one specific set of data, we also verify the performance using a simulated publicly available data set. We show that both proposed algorithms have the best performance under all tested methods, regardless of the signal-to-noise ratio in both data sets. This contribution will redound to the benefit of electrophysiological investigations of human cells. Especially the spatial and temporal analysis of neural network communications is improved by using the proposed spike detection algorithms.

  16. A stationary wavelet transform and a time-frequency based spike detection algorithm for extracellular recorded data

    Science.gov (United States)

    Lieb, Florian; Stark, Hans-Georg; Thielemann, Christiane

    2017-06-01

    Objective. Spike detection from extracellular recordings is a crucial preprocessing step when analyzing neuronal activity. The decision whether a specific part of the signal is a spike or not is important for any kind of other subsequent preprocessing steps, like spike sorting or burst detection in order to reduce the classification of erroneously identified spikes. Many spike detection algorithms have already been suggested, all working reasonably well whenever the signal-to-noise ratio is large enough. When the noise level is high, however, these algorithms have a poor performance. Approach. In this paper we present two new spike detection algorithms. The first is based on a stationary wavelet energy operator and the second is based on the time-frequency representation of spikes. Both algorithms are more reliable than all of the most commonly used methods. Main results. The performance of the algorithms is confirmed by using simulated data, resembling original data recorded from cortical neurons with multielectrode arrays. In order to demonstrate that the performance of the algorithms is not restricted to only one specific set of data, we also verify the performance using a simulated publicly available data set. We show that both proposed algorithms have the best performance under all tested methods, regardless of the signal-to-noise ratio in both data sets. Significance. This contribution will redound to the benefit of electrophysiological investigations of human cells. Especially the spatial and temporal analysis of neural network communications is improved by using the proposed spike detection algorithms.

  17. Detection of low frequency FGFR3 mutations in the urine of bladder cancer patients using next-generation deep sequencing

    Directory of Open Access Journals (Sweden)

    Millholl

    2012-06-01

    Full Text Available John M Millholland, Shuqiang Li, Cecilia A Fernandez, Anthony P ShuberPredictive Biosciences Inc, Lexington, MA, USAAbstract: Biological fluid-based noninvasive biomarker assays for monitoring and diagnosing disease are clinically powerful. A major technical hurdle for developing these assays is the requirement of high analytical sensitivity so that biomarkers present at very low levels can be consistently detected. In the case of biological fluid-based cancer diagnostic assays, sensitivities similar to those of tissue-based assays are difficult to achieve with DNA markers due to the high abundance of normal DNA background present in the sample. Here we describe a new urine-based assay that uses ultradeep sequencing technology to detect single mutant molecules of fibroblast growth factor receptor 3 (FGFR3 DNA that are indicative of bladder cancer. Detection of FGFR3 mutations in urine would provide clinicians with a noninvasive means of diagnosing early-stage bladder cancer. The single-molecule assay detects FGFR3 mutant DNA when present at as low as 0.02% of total urine DNA and results in 91% concordance with the frequency that FGFR3 mutations are detected in bladder cancer tumors, significantly improving diagnostic performance. To our knowledge, this is the first practical application of next-generation sequencing technology for noninvasive cancer diagnostics.Keywords: FGFR3, mutation, urine, single molecule, sequencing, bladder cancer

  18. Detection of low frequency multi-drug resistance and novel putative maribavir resistance in immunocompromised paediatric patients with cytomegalovirus

    Directory of Open Access Journals (Sweden)

    Charlotte Jane Houldcroft

    2016-09-01

    Full Text Available Human cytomegalovirus (HCMV is a significant pathogen in immunocompromised individuals, with the potential to cause fatal pneumonitis and colitis, as well as increasing the risk of organ rejection in transplant patients. With the advent of new anti-HCMV drugs there is therefore considerable interest in using virus sequence data to monitor emerging resistance to antiviral drugs in HCMV viraemia and disease, including the identification of putative new mutations. We used target-enrichment to deep sequence HCMV DNA from 11 immunosuppressed paediatric patients receiving single or combination anti-HCMV treatment, serially sampled over 1-27 weeks. Changes in consensus sequence and resistance mutations were analysed for three ORFs targeted by anti-HCMV drugs and the frequencies of drug resistance mutations monitored. Targeted-enriched sequencing of clinical material detected mutations occurring at frequencies of 2%. Seven patients showed no evidence of drug resistance mutations. Four patients developed drug resistance mutations a mean of 16 weeks after starting treatment. In two patients, multiple resistance mutations accumulated at frequencies of 20% or less, including putative maribavir and ganciclovir resistance mutations P522Q (UL54 and C480F (UL97. In one patient, resistance was detected 14 days earlier than by PCR. Phylogenetic analysis suggested recombination or superinfection in one patient. Deep sequencing of HCMV enriched from clinical samples excluded resistance in 7 of eleven subjects and identified resistance mutations earlier than conventional PCR-based resistance testing in 2 patients. Detection of multiple low level resistance mutations was associated with poor outcome.

  19. Frequency and significance of thoracic injuries detected on abdominal trauma CT scans

    International Nuclear Information System (INIS)

    Hareli, G.S.; Rhea, J.T.; Novelline, R.A.; Lawrason, N.; Sacknoff, R.; Oser, A.

    1987-01-01

    The authors have noted that in multiple trauma patients chest injuries inapparent on initial chest radiographs may be detected at abdominal CT. In an ongoing series of 112 patients to date, 50 chest injuries were detected in 33 patients (29%). The injuries included 15 bilateral hemothoraces, seven unilateral hemothoraces, seven posttraumatic atrelectasis, seven lung contusions, five pneumothoraces, four rib factures, two thoracic spine fractures, two chest wall emphysema, and one mediastinal emphysema. In 24 of the 33 patients (72%) the injury was not seen on the initial chest radiographs; in seven patients treatment of the chest injury was required. The authors have included screening cuts of the middle and upper chest as part of their abdominal CT protocol

  20. A power filter for the detection of burst events based on time-frequency spectrum estimation

    International Nuclear Information System (INIS)

    Guidi, G M; Cuoco, E; Vicere, A

    2004-01-01

    We propose as a statistic for the detection of bursts in a gravitational wave interferometer the 'energy' of the events estimated with a time-dependent calculation of the spectrum. This statistic has an asymptotic Gaussian distribution with known statistical moments, which makes it possible to perform a uniformly most powerful test (McDonough R N and Whalen A D 1995 Detection of Signals in Noise (New York: Academic)) on the energy mean. We estimate the receiver operating characteristic (ROC, from the same book) of this statistic for different levels of the signal-to-noise ratio in the specific case of a simulated noise having the spectral density expected for Virgo, using test signals taken from a library of possible waveforms emitted during the collapse of the core of type II supernovae

  1. Detection of intensity bursts using Hawkes processes: An application to high-frequency financial data

    Science.gov (United States)

    Rambaldi, Marcello; Filimonov, Vladimir; Lillo, Fabrizio

    2018-03-01

    Given a stationary point process, an intensity burst is defined as a short time period during which the number of counts is larger than the typical count rate. It might signal a local nonstationarity or the presence of an external perturbation to the system. In this paper we propose a procedure for the detection of intensity bursts within the Hawkes process framework. By using a model selection scheme we show that our procedure can be used to detect intensity bursts when both their occurrence time and their total number is unknown. Moreover, the initial time of the burst can be determined with a precision given by the typical interevent time. We apply our methodology to the midprice change in foreign exchange (FX) markets showing that these bursts are frequent and that only a relatively small fraction is associated with news arrival. We show lead-lag relations in intensity burst occurrence across different FX rates and we discuss their relation with price jumps.

  2. Glaucoma progression detection with frequency doubling technology (FDT) compared to standard automated perimetry (SAP) in the Groningen Longitudinal Glaucoma Study.

    Science.gov (United States)

    Wesselink, Christiaan; Jansonius, Nomdo M

    2017-09-01

    To determine the usefulness of frequency doubling perimetry (FDT) for progression detection in glaucoma, compared to standard automated perimetry (SAP). Data were used from 150 eyes of 150 glaucoma patients from the Groningen Longitudinal Glaucoma Study. After baseline, SAP was performed approximately yearly; FDT every other year. First and last visit had to contain both tests. Using linear regression, progression velocities were calculated for SAP (Humphrey Field Analyzer) mean deviation (MD) and FDT MD and the number of test locations with a total deviation probability below p glaucoma progression in patients who cannot perform SAP reliably. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

  3. Detection, Properties, and Frequency of Local Calcium Release from the Sarcoplasmic Reticulum in Teleost Cardiomyocytes

    OpenAIRE

    Llach, Anna; Molina, Cristina E.; Alvarez Lacalle, Enrique; Tort, Lluis; Benítez, Raul; Hove, Leif

    2011-01-01

    Calcium release from the sarcoplasmic reticulum (SR) plays a central role in the regulation of cardiac contraction and rhythm in mammals and humans but its role is controversial in teleosts. Since the zebrafish is an emerging model for studies of cardiovascular function and regeneration we here sought to determine if basic features of SR calcium release are phylogenetically conserved. Confocal calcium imaging was used to detect spontaneous calcium release (calcium sparks and waves) from...

  4. Detection of Fatigue Damage by Using Frequency Attenuation of a Laser Ultrasonic Longitudinal Wave

    International Nuclear Information System (INIS)

    Park, Seung-Kyu; Baik, Sung-Hoon; Jung, Hyun-Kyu; Joo, Young-Sang; Cha, Hyung-Ki; Kang, Young-June

    2006-01-01

    The measurement of fatigue damage in nuclear power plant components is very important to prevent a catastrophic accident and the subsequent severe losses. Specifically, it is preferred to detect at an early stage of the fatigue damage. If the fatigue damage that is in danger of growing into a fracture is accurately detected, an appropriate treatment could be carried out to improve the condition. Although most engineers and designers take precautions against fatigue, some breakdowns of nuclear power plant components still occur due to fatigue damage. It is considered that ultrasound testing technique is the most promising method to detect the fatigue damage in many nondestructive testing methods. Ultrasound testing method has a variety of elastic waves, such as a longitudinal wave, a shear wave, a surface wave and a lamb wave. Also we can use various analysis methods, such as a velocity variation and a signal attenuation. Laser ultrasonic testing has attracted attention as a non-contact testing technique. This system consists of a pulse laser to remotely generate ultrasound and a laser interferometer to remotely measure the surface displacement due to the generated ultrasound. This noncontact testing technique has the following advantages over the conventional piezoelectric transducers. Firstly, the inspection system can be remotely operated for a structure in hostile environments, such as in high radioactivity, high temperatures and narrow spaces. Secondly, we can obtain lots of information from the received ultrasonic waveforms because the laser ultrasonic technique does not require fluid couplant which disturbs the ultrasonic waveforms. Thirdly, laser ultrasound has a wideband spectrum and a high spatial resolution. Therefore, the laser ultrasound provides more accurate information for a testing material and has potential for the detection of fatigue damage in various metals composing a nuclear power plant

  5. Analytical Approach to Target Detection and Localization at High-Frequency Bands Using Multipath Propagation

    Science.gov (United States)

    2016-04-25

    ElectroMagnetic, Multipath propagation, Reflection-diffraction, SAR signal processing 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18...protection, and traffic surveillance, etc. With these above reasons, we are motivated to introduce a new approach to the target detection and...coherent integrating the backscattering signal , we propose a 3D propagation model that is useful not only in explaining the mechanisms of wave

  6. Damaged Watermarks Detection in Frequency Domain as a Primary Method for Video Concealment

    Directory of Open Access Journals (Sweden)

    Robert Hudec

    2011-01-01

    Full Text Available This paper deals with video transmission over lossy communication networks. The main idea is to develop video concealment method for information losses and errors correction. At the beginning, three main groups of video concealment methods, divided by encoder/decoder collaboration, are briefly described. The modified algorithm based on the detection and filtration of damaged watermark blocks encapsulated to the transmitted video was developed. Finally, the efficiency of developed algorithm is presented in experimental part of this paper.

  7. RIPPLELAB: A Comprehensive Application for the Detection, Analysis and Classification of High Frequency Oscillations in Electroencephalographic Signals.

    Directory of Open Access Journals (Sweden)

    Miguel Navarrete

    Full Text Available High Frequency Oscillations (HFOs in the brain have been associated with different physiological and pathological processes. In epilepsy, HFOs might reflect a mechanism of epileptic phenomena, serving as a biomarker of epileptogenesis and epileptogenicity. Despite the valuable information provided by HFOs, their correct identification is a challenging task. A comprehensive application, RIPPLELAB, was developed to facilitate the analysis of HFOs. RIPPLELAB provides a wide range of tools for HFOs manual and automatic detection and visual validation; all of them are accessible from an intuitive graphical user interface. Four methods for automated detection-as well as several options for visualization and validation of detected events-were implemented and integrated in the application. Analysis of multiple files and channels is possible, and new options can be added by users. All features and capabilities implemented in RIPPLELAB for automatic detection were tested through the analysis of simulated signals and intracranial EEG recordings from epileptic patients (n = 16; 3,471 analyzed hours. Visual validation was also tested, and detected events were classified into different categories. Unlike other available software packages for EEG analysis, RIPPLELAB uniquely provides the appropriate graphical and algorithmic environment for HFOs detection (visual and automatic and validation, in such a way that the power of elaborated detection methods are available to a wide range of users (experts and non-experts through the use of this application. We believe that this open-source tool will facilitate and promote the collaboration between clinical and research centers working on the HFOs field. The tool is available under public license and is accessible through a dedicated web site.

  8. DETECTING FLARING STRUCTURES IN SAGITTARIUS A* WITH HIGH-FREQUENCY VLBI

    International Nuclear Information System (INIS)

    Doeleman, Sheperd S.; Fish, Vincent L.; Rogers, Alan E. E.; Broderick, Avery E.; Loeb, Abraham

    2009-01-01

    The super-massive black hole candidate, Sagittarius A*, exhibits variability from radio to X-ray wavelengths on timescales that correspond to <10 Schwarzschild radii. We survey the potential of millimeter wavelength very long baseline interferometry (VLBI) to detect and constrain time-variable structures that could give rise to such variations, focusing on a model in which an orbiting hot spot is embedded in an accretion disk. Nonimaging algorithms are developed that use interferometric closure quantities to test for periodicity, and applied to an ensemble of hot spot models that sample a range of parameter space. We find that structural periodicity in a wide range of cases can be detected on most potential VLBI arrays using modern VLBI instrumentation. Future enhancements of millimeter/submillimeter VLBI arrays including phased-array processors to aggregate VLBI station collecting area, increased bandwidth recording, and addition of new VLBI sites all significantly aid periodicity detection. The methods described herein can be applied to other models of Sagittarius A*, including jet outflows and magnetohydrodynamic accretion simulations.

  9. Higher-Order Statistics for the Detection of Small Objects in a Noisy Background Application on Sonar Imaging

    Directory of Open Access Journals (Sweden)

    M. Amate

    2007-01-01

    Full Text Available An original algorithm for the detection of small objects in a noisy background is proposed. Its application to underwater objects detection by sonar imaging is addressed. This new method is based on the use of higher-order statistics (HOS that are locally estimated on the images. The proposed algorithm is divided into two steps. In a first step, HOS (skewness and kurtosis are estimated locally using a square sliding computation window. Small deterministic objects have different statistical properties from the background they are thus highlighted. The influence of the signal-to-noise ratio (SNR on the results is studied in the case of Gaussian noise. Mathematical expressions of the estimators and of the expected performances are derived and are experimentally confirmed. In a second step, the results are focused by a matched filter using a theoretical model. This enables the precise localization of the regions of interest. The proposed method generalizes to other statistical distributions and we derive the theoretical expressions of the HOS estimators in the case of a Weibull distribution (both when only noise is present or when a small deterministic object is present within the filtering window. This enables the application of the proposed technique to the processing of synthetic aperture sonar data containing underwater mines whose echoes have to be detected and located. Results on real data sets are presented and quantitatively evaluated using receiver operating characteristic (ROC curves.

  10. LISA and LISA PathFinder, the endeavour to detect low frequency GWs

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, H [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Boatella, C [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Chmeissani, M [Institut de Fisica d' Altes Energies (IFAE), Edifici C, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Conchillo, A [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Garcia-Berro, E [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Grimani, C [Universita degli Studi di Urbino, and INFN Florence, Istituto di Fisica, Via Santa Chiara 27, 61029 Urbino (Italy); Hajdas, W [Department of Particles and Matter, Paul Scherrer Institut, ODRA 120, 5232 Villigen (Switzerland); Lobo, A [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Martinez, L [AtIpic, Parc Tecnologic del Valles, 08290 Cerdanyola del Valles, Barcelona (Spain); Nofrarias, M [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Ortega, J A [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Puigdengoles, C [Institut de Fisica d' Altes Energies (IFAE), Edifici C, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Ramos-Castro, J [Departament d' Enginyeria Electronica, UPC, Campus Nord, Edif. C4, Jordi Girona 1-3, 08034 Barcelona (Spain); Sanjuan, J [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Wass, P [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Xirgu, X [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain)

    2007-05-15

    This is a review about LISA and its technology demonstrator, LISAPathFinder. We first describe the conceptual problems which need to be overcome in order to set up a working interferometric detector of low frequency Gravitational Waves (GW), then summarise the solutions to them as currently conceived by the LISA mission team. This will show that some of these solutions require new technological abilities which are still under development, and which need proper test before being fully implemented. LISAPathFinder (LPF) is the the testbed for such technologies. The final part of the paper will address the ideas and concepts behind the PathFinder as well as their impact on LISA.

  11. A technique for rocket-borne detection of electron bunching at megahertz frequencies

    International Nuclear Information System (INIS)

    Gough, M.P.

    1980-01-01

    Energetic electrons precipitating in the auroral ionosphere may be bunched at frequencies up to several megahertz as a result of local wave-particle interactions. A technique is described whereby this megahertz bunching can be observed using conventional rocket-borne energetic electron detectors counting at rates below 10 5 cps. Electron arrival time information is pre-processed on board the rocket and any bunching present can be realized by subsequent computer processing on the ground using only a modest data transmission rate from the rocket. Results of a pilot rocket experiment prove the value of the technique and lead on to formulating the design of a future experiment where the maximum amount of data processing is performed on the rocket. The technique should perform an important diagnostic role, helping us to understand the complex wave-particle interactions occurring in the auroral ionosphere. (orig.)

  12. Frequency-modulated impulse response photothermal detection through optical reflectance. 2: Experimental.

    Science.gov (United States)

    Power, J F; Mandelis, A

    1988-08-15

    A fast thermoreflectance impulse response photothermal imager was assembled and tested with several solid materials [quartz, stainless steel, and polyvinylidene difluoride (PVDF)I. The instrument was found to yield quantitative data in agreement with Green's function theoretical models of time domain heat conduction. The FM chirp laser intensity modulation technique used in these experiments gave wide bandwidth photothermal signals and was found to be only limited by the FFT instrumentation frequency response (100 kHz). Thermal diffusivities were calculated, while thermal lensing and thermoelastic effects were further observed. The imager was thus shown to be capable of replacing pulsed laser devices for truly nondestructive applications with materials with low damage threshold to optical pulses.

  13. Radial Photonic Crystal for detection of frequency and position of radiation sources.

    Science.gov (United States)

    Carbonell, J; Díaz-Rubio, A; Torrent, D; Cervera, F; Kirleis, M A; Piqué, A; Sánchez-Dehesa, J

    2012-01-01

    Based on the concepts of artificially microstructured materials, i.e. metamaterials, we present here the first practical realization of a radial wave crystal. This type of device was introduced as a theoretical proposal in the field of acoustics, and can be briefly defined as a structured medium with radial symmetry, where the constitutive parameters are invariant under radial geometrical translations. Our practical demonstration is realized in the electromagnetic microwave spectrum, because of the equivalence between the wave problems in both fields. A device has been designed, fabricated and experimentally characterized. It is able to perform beam shaping of punctual wave sources, and also to sense position and frequency of external radiators. Owing to the flexibility offered by the design concept, other possible applications are discussed.

  14. LISA and LISA PathFinder, the endeavour to detect low frequency GWs

    International Nuclear Information System (INIS)

    Araujo, H; Boatella, C; Chmeissani, M; Conchillo, A; Garcia-Berro, E; Grimani, C; Hajdas, W; Lobo, A; Martinez, L; Nofrarias, M; Ortega, J A; Puigdengoles, C; Ramos-Castro, J; Sanjuan, J; Wass, P; Xirgu, X

    2007-01-01

    This is a review about LISA and its technology demonstrator, LISAPathFinder. We first describe the conceptual problems which need to be overcome in order to set up a working interferometric detector of low frequency Gravitational Waves (GW), then summarise the solutions to them as currently conceived by the LISA mission team. This will show that some of these solutions require new technological abilities which are still under development, and which need proper test before being fully implemented. LISAPathFinder (LPF) is the the testbed for such technologies. The final part of the paper will address the ideas and concepts behind the PathFinder as well as their impact on LISA

  15. Contactless and absolute linear displacement detection based upon 3D printed magnets combined with passive radio-frequency identification

    Science.gov (United States)

    Windl, Roman; Abert, Claas; Bruckner, Florian; Huber, Christian; Vogler, Christoph; Weitensfelder, Herbert; Suess, Dieter

    2017-11-01

    Within this work a passive and wireless magnetic sensor, to monitor linear displacements, is proposed. We exploit recent advances in 3D printing and fabricate a polymer bonded magnet with a spatially linear magnetic field component corresponding to the length of the magnet. Regulating the magnetic compound fraction during printing allows specific shaping of the magnetic field distribution. A giant magnetoresistance magnetic field sensor is combined with a radio-frequency identification tag in order to passively monitor the exerted magnetic field of the printed magnet. Due to the tailored magnetic field, a displacement of the magnet with respect to the sensor can be detected within the sub-mm regime. The sensor design provides good flexibility by controlling the 3D printing process according to application needs. Absolute displacement detection using low cost components and providing passive operation, long term stability, and longevity renders the proposed sensor system ideal for structural health monitoring applications.

  16. Contactless and absolute linear displacement detection based upon 3D printed magnets combined with passive radio-frequency identification

    Directory of Open Access Journals (Sweden)

    Roman Windl

    2017-11-01

    Full Text Available Within this work a passive and wireless magnetic sensor, to monitor linear displacements, is proposed. We exploit recent advances in 3D printing and fabricate a polymer bonded magnet with a spatially linear magnetic field component corresponding to the length of the magnet. Regulating the magnetic compound fraction during printing allows specific shaping of the magnetic field distribution. A giant magnetoresistance magnetic field sensor is combined with a radio-frequency identification tag in order to passively monitor the exerted magnetic field of the printed magnet. Due to the tailored magnetic field, a displacement of the magnet with respect to the sensor can be detected within the sub-mm regime. The sensor design provides good flexibility by controlling the 3D printing process according to application needs. Absolute displacement detection using low cost components and providing passive operation, long term stability, and longevity renders the proposed sensor system ideal for structural health monitoring applications.

  17. Note of non-destructive detection of voids by a high frequency inversion technique

    International Nuclear Information System (INIS)

    Cohen, J.K.; Bleistein, N.

    1978-01-01

    An inverse method for nondestructive detection of scatterers of high contrast, such as voids or strongly reflecting inclusions, is described. The phase and range normalized far field scattering amplitude is shown to be directly proportional to the Fourier transform of the characteristic function of the scatterer. The characteristic function is equal to unity inside the region occupied by the scatterer and is zero outside. Thus, knowledge of this function provides a description of the scatterer. The method is applied to flaws in a sphere

  18. Warfarin maintenance dose in older patients: higher average dose and wider dose frequency distribution in patients of African ancestry than those of European ancestry.

    Science.gov (United States)

    Garwood, Candice L; Clemente, Jennifer L; Ibe, George N; Kandula, Vijay A; Curtis, Kristy D; Whittaker, Peter

    2010-06-15

    Studies report that warfarin doses required to maintain therapeutic anticoagulation decrease with age; however, these studies almost exclusively enrolled patients of European ancestry. Consequently, universal application of dosing paradigms based on such evidence may be confounded because ethnicity also influences dose. Therefore, we determined if warfarin dose decreased with age in Americans of African ancestry, if older African and European ancestry patients required different doses, and if their daily dose frequency distributions differed. Our chart review examined 170 patients of African ancestry and 49 patients of European ancestry cared for in our anticoagulation clinic. We calculated the average weekly dose required for each stable, anticoagulated patient to maintain an international normalized ratio of 2.0 to 3.0, determined dose averages for groups 80 years of age and plotted dose as a function of age. The maintenance dose in patients of African ancestry decreased with age (PAfrican ancestry required higher average weekly doses than patients of European ancestry: 33% higher in the 70- to 79-year-old group (38.2+/-1.9 vs. 28.8+/-1.7 mg; P=0.006) and 52% in the >80-year-old group (33.2+/-1.7 vs. 21.8+/-3.8 mg; P=0.011). Therefore, 43% of older patients of African ancestry required daily doses >5mg and hence would have been under-dosed using current starting-dose guidelines. The dose frequency distribution was wider for older patients of African ancestry compared to those of European ancestry (PAfrican ancestry indicate that strategies for initiating warfarin therapy based on studies of patients of European ancestry could result in insufficient anticoagulation and thereby potentially increase their thromboembolism risk. Copyright 2010 Elsevier Inc. All rights reserved.

  19. Investigation of Using Radio Frequency Identification (RFID) System for Gear Tooth Crack Detection

    Science.gov (United States)

    2014-06-01

    on a conveyor belt at a certain speed. When compared to the static application, moving tags spend less time in the read field and require a higher...However, it was found that wireless communication distances shrink dramatically when placed in metal-rich environments, even with large purpose- designed ...the antennas used for both reader and tag are generally based on a coil or loop design . To achieve wireless communication between the reader and the

  20. [Design of High Frequency Signal Detecting Circuit of Human Body Impedance Used for Ultrashort Wave Diathermy Apparatus].

    Science.gov (United States)

    Fan, Xu; Wang, Yunguang; Cheng, Haiping; Chong, Xiaochen

    2016-02-01

    The present circuit was designed to apply to human tissue impedance tuning and matching device in ultra-short wave treatment equipment. In order to judge if the optimum status of circuit parameter between energy emitter circuit and accepter circuit is in well syntony, we designed a high frequency envelope detect circuit to coordinate with automatic adjust device of accepter circuit, which would achieve the function of human tissue impedance matching and tuning. Using the sampling coil to receive the signal of amplitude-modulated wave, we compared the voltage signal of envelope detect circuit with electric current of energy emitter circuit. The result of experimental study was that the signal, which was transformed by the envelope detect circuit, was stable and could be recognized by low speed Analog to Digital Converter (ADC) and was proportional to the electric current signal of energy emitter circuit. It could be concluded that the voltage, transformed by envelope detect circuit can mirror the real circuit state of syntony and realize the function of human tissue impedance collecting.

  1. Structural Damage Detection using Frequency Response Function Index and Surrogate Model Based on Optimized Extreme Learning Machine Algorithm

    Directory of Open Access Journals (Sweden)

    R. Ghiasi

    2017-09-01

    Full Text Available Utilizing surrogate models based on artificial intelligence methods for detecting structural damages has attracted the attention of many researchers in recent decades. In this study, a new kernel based on Littlewood-Paley Wavelet (LPW is proposed for Extreme Learning Machine (ELM algorithm to improve the accuracy of detecting multiple damages in structural systems.  ELM is used as metamodel (surrogate model of exact finite element analysis of structures in order to efficiently reduce the computational cost through updating process. In the proposed two-step method, first a damage index, based on Frequency Response Function (FRF of the structure, is used to identify the location of damages. In the second step, the severity of damages in identified elements is detected using ELM. In order to evaluate the efficacy of ELM, the results obtained from the proposed kernel were compared with other kernels proposed for ELM as well as Least Square Support Vector Machine algorithm. The solved numerical problems indicated that ELM algorithm accuracy in detecting structural damages is increased drastically in case of using LPW kernel.

  2. Software Design and Implementation of a Next Generation GNSS Data Logger for Radio Frequency Interference Detection

    Science.gov (United States)

    Rivera, Sean

    The aim of this thesis is to implement a new GNSS interference detection system that extends the functionality of previous systems. This technology will be evaluated on the effectiveness of data collection in GPS L1, GPS L2C and all software changes required to implement it. Additionally there is discussion about extending the technology to log GLONASS L1 and GLONASS L2 data. This thesis is broken up into three sections. First, it describes the current state of GPS ASIC systems, using the SiGe receiver. It covers the reasons that this ASIC requires modernization as well as what behavior the system seeks to emulate. Next, it describes the new hardware that will make up the base of the new system. It covers what each component has been added for and its differences from the previous version. The focus is on the new ability of the receiver to receiver L2C simultaneously with L1 as well as the increased data rate which allows for better positioning. Finally, the thesis describes new software development effort centered around the new system. The thesis describes three test modes used, continuous logging, triggered logging and periodic logging. Extra attention is paid to the implementation of a real time networked version of the code. The final goal of the thesis is to build a low cost distributed system that is capable of detecting and localizing GPS and GLONASS interference on both the L1 and L2 bands.

  3. RIPPLELAB: A Comprehensive Application for the Detection, Analysis and Classification of High Frequency Oscillations in Electroencephalographic Signals

    Science.gov (United States)

    Alvarado-Rojas, Catalina; Le Van Quyen, Michel; Valderrama, Mario

    2016-01-01

    High Frequency Oscillations (HFOs) in the brain have been associated with different physiological and pathological processes. In epilepsy, HFOs might reflect a mechanism of epileptic phenomena, serving as a biomarker of epileptogenesis and epileptogenicity. Despite the valuable information provided by HFOs, their correct identification is a challenging task. A comprehensive application, RIPPLELAB, was developed to facilitate the analysis of HFOs. RIPPLELAB provides a wide range of tools for HFOs manual and automatic detection and visual validation; all of them are accessible from an intuitive graphical user interface. Four methods for automated detection—as well as several options for visualization and validation of detected events—were implemented and integrated in the application. Analysis of multiple files and channels is possible, and new options can be added by users. All features and capabilities implemented in RIPPLELAB for automatic detection were tested through the analysis of simulated signals and intracranial EEG recordings from epileptic patients (n = 16; 3,471 analyzed hours). Visual validation was also tested, and detected events were classified into different categories. Unlike other available software packages for EEG analysis, RIPPLELAB uniquely provides the appropriate graphical and algorithmic environment for HFOs detection (visual and automatic) and validation, in such a way that the power of elaborated detection methods are available to a wide range of users (experts and non-experts) through the use of this application. We believe that this open-source tool will facilitate and promote the collaboration between clinical and research centers working on the HFOs field. The tool is available under public license and is accessible through a dedicated web site. PMID:27341033

  4. Accounting for binaural detection as a function of masker interaural correlation: effects of center frequency and bandwidth.

    Science.gov (United States)

    Bernstein, Leslie R; Trahiotis, Constantine

    2014-12-01

    Binaural detection was measured as a function of the center frequency, bandwidth, and interaural correlation of masking noise. Thresholds were obtained for 500-Hz or 125-Hz Sπ tonal signals and for the latter stimuli (noise or signal-plus-noise) transposed to 4 kHz. A primary goal was assessment of the generality of van der Heijden and Trahiotis' [J. Acoust. Soc. Am. 101, 1019-1022 (1997)] hypothesis that thresholds could be accounted for by the "additive" masking effects of the underlying No and Nπ components of a masker having an interaural correlation of ρ. Results indicated that (1) the overall patterning of the data depended neither upon center frequency nor whether information was conveyed via the waveform or by its envelope; (2) thresholds for transposed stimuli improved relative to their low-frequency counterparts as bandwidth of the masker was increased; (3) the additivity approach accounted well for the data across stimulus conditions but consistently overestimated MLDs, especially for narrowband maskers; (4) a quantitative approach explicitly taking into account the distributions of time-varying ITD-based lateral positions produced by masker-alone and signal-plus-masker waveforms proved more successful, albeit while employing a larger set of assumptions, parameters, and computational complexity.

  5. Frequency of motor alterations detected through manometry in patients with esophageal symptoms and scleroderma.

    Science.gov (United States)

    Pérez Y López, N; Lugo-Zamudio, G; Barbosa-Cobos, R E; Wong-Lam, A; Torres-López, E

    Scleroderma can present with esophageal involvement causing important morbidity. To describe the manometric findings and clinical characteristics of patients with scleroderma and esophageal symptoms. Patients with scleroderma and esophageal symptoms were evaluated through esophageal manometry within the time frame of one year. Descriptive statistics were carried out and the continuous variables were expressed as means and standard deviation. Frequencies were expressed as percentages. The study included 24 female patients with a mean age of 53.5 years and mean disease progression of 7.84 years. The most frequent findings were short and hypotonic lower esophageal sphincter (mean length 1.58cm and mean tone 9.49mmHg) and ineffective esophageal motility (mean non-transmitted waves 92.91%, mean effective primary peristalsis 40.05%, and mean amplitude 13.11mmHg). The most frequent symptom was dysphagia. Scleroderma is associated with lower esophageal sphincter alterations and symptomatic ineffective esophageal motility. Copyright © 2017 Asociación Mexicana de Gastroenterología. Publicado por Masson Doyma México S.A. All rights reserved.

  6. MIR-difference-frequency laser spectrometer for CO detection in combustions

    Directory of Open Access Journals (Sweden)

    A. Khorsandi

    2003-06-01

    Full Text Available  Two continuous-wave (cw single mode diode-lasers (Toshiba TOLD 9150 and Sharp LT024MDO are applied as pump and signal sources to obtain difference-frequency generation (DFG in the mid-infrared (MIR region by using an AgGaS2 crystal with a length of 30 mm for 90° type I phase-matching. Tuneable MIR laser radiation around 5 µm is obtained with an output power in the order of hundred nW while the diode lasers are operated at 20 and 30 mW around their centre wavelengths 789 and 681 nm, respectively. To demonstrate the applicability of this MIR-DFG laser spectrometer we recorded the absorption spectrum of CO for the P(21 rotational line at 2055.4 cm-1 in a 10 cm long cell and in the flame of a McKenna burner in order to estimate the self-broadening coefficient of CO, the collisional-broadening of CO with CO2, and the CO concentration distribution in the flame.

  7. Detection of Local Temperature Change on HTS Cables via Time-Frequency Domain Reflectometry

    Science.gov (United States)

    Bang, Su Sik; Lee, Geon Seok; Kwon, Gu-Young; Lee, Yeong Ho; Ji, Gyeong Hwan; Sohn, Songho; Park, Kijun; Shin, Yong-June

    2017-07-01

    High temperature superconducting (HTS) cables are drawing attention as transmission and distribution cables in future grid, and related researches on HTS cables have been conducted actively. As HTS cables have come to the demonstration stage, failures of cooling systems inducing quench phenomenon of the HTS cables have become significant. Several diagnosis of the HTS cables have been developed but there are still some limitations of the experimental setup. In this paper, a non-destructive diagnostic technique for the detection of the local temperature change point is proposed. Also, a simulation model of HTS cables with a local temperature change point is suggested to verify the proposed diagnosis. The performance of the diagnosis is checked by comparative analysis between the proposed simulation results and experiment results of a real-world HTS cable. It is expected that the suggested simulation model and diagnosis will contribute to the commercialization of HTS cables in the power grid.

  8. Solar g-modes? Comparison of detected asymptotic g-mode frequencies with solar model predictions

    Science.gov (United States)

    Wood, Suzannah Rebecca; Guzik, Joyce Ann; Mussack, Katie; Bradley, Paul A.

    2018-06-01

    After many years of searching for solar gravity modes, Fossat et al. (2017) reported detection of the nearly equally spaced high-order g-modes periods using a 15-year time series of GOLF data from the SOHO spacecraft. Here we report progress towards and challenges associated with calculating and comparing g-mode period predictions for several previously published standard solar models using various abundance mixtures and opacities, as well as the predictions for some non-standard models incorporating early mass loss, and compare with the periods reported by Fossat et al (2017). Additionally, we have a side-by-side comparison of results of different stellar pulsation codes for calculating g-mode predictions. These comparisons will allow for testing of nonstandard physics input that affect the core, including an early more massive Sun and dynamic electron screening.

  9. Study of higher hydrocarbon production during ethylacetylene pyrolysis using laser-generated vacuum-ultraviolet photoionization detection

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, J.; Pfefferle, L. (Yale Univ., New Haven, CT (USA))

    1990-04-19

    Higher hydrocarbon formation during the pyrolysis of ethylacetylene in a microjet reactor was studied by vacuum-ultraviolet photoionization time-of-flight mass spectrometry. At the wavelength employed, this ionization technique allows for the simultaneous detection of both stable and intermediate polyatomic species with ionization potentials below 10.49 eV, including most hydrocarbons with two or more carbon atoms. Minimal fragmentation simplifies the determination of parent species and allows identification of probable reaction pathways involving hydrocarbon radicals as well as stable species. The pyrolysis of ethylacetylene was carried out in the fast-flow microjet reactor (residence times 1-2 ms) at temperatures from 300 to 1,600 K.

  10. Application of Frequency of Detection Methods in Design and Optimization of the INL Site Ambient Air Monitoring Network

    Energy Technology Data Exchange (ETDEWEB)

    Rood, Arthur S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sondrup, A. Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-11-01

    This report presents an evaluation of a hypothetical INL Site monitoring network and the existing INL air monitoring network using frequency of detection methods. The hypothetical network was designed to address the requirement in 40 CFR Part 61, Subpart H (2006) that “emissions of radionuclides to ambient air from U.S. DOE facilities shall not exceed those amounts that would cause any member of the public to receive in any year an effective dose equivalent exceeding 10 mrem/year.” To meet the requirement for monitoring only, “radionuclide releases that would result in an effective dose of 10% of the standard shall be readily detectable and distinguishable from background.” Thus, the hypothetical network consists of air samplers placed at residence locations that surround INL and at other locations where onsite livestock grazing takes place. Two exposure scenarios were used in this evaluation: a resident scenario and a shepherd/rancher scenario. The resident was assumed to be continuously present at their residence while the shepherd/rancher was assumed to be present 24-hours at a fixed location on the grazing allotment. Important radionuclides were identified from annual INL radionuclide National Emission Standards for Hazardous Pollutants reports. Important radionuclides were defined as those that potentially contribute 1% or greater to the annual total dose at the radionuclide National Emission Standards for Hazardous Pollutants maximally exposed individual location and include H-3, Am-241, Pu-238, Pu 239, Cs-137, Sr-90, and I-131. For this evaluation, the network performance objective was set at achieving a frequency of detection greater than or equal to 95%. Results indicated that the hypothetical network for the resident scenario met all performance objectives for H-3 and I-131 and most performance objectives for Cs-137 and Sr-90. However, all actinides failed to meet the performance objectives for most sources. The shepherd/rancher scenario showed

  11. Experimental high-frequency ultrasound can detect graft rejection after small bowel transplantation.

    Science.gov (United States)

    Yang, R; Liu, Q; Wu, E X; Pescovitz, M D; Collins, M H; Kopecky, K K; Grosfeld, J L

    1994-02-01

    Early diagnosis of graft rejection after small bowel transplantation (SBT) can allow prompt institution of vigorous immunosuppressive therapy, with resultant reversal of the rejection process. The current method for graft monitoring is random mucosal biopsy from a stomal site or through an endoscope. However, because early rejection often has a patchy distribution, it could be missed by random biopsy. We hypothesized that the pathological process of rejection would alter acoustic impedance of the tissue and thus change the ultrasonic patterns of the graft intestinal wall. If this hypothesis is correct, then high-frequency endoscopic ultrasound (US) could be used to monitor the entire transplanted bowel and guide the biopsy, with improved yields. This hypothesis was tested in a rat orthotopic SBT model. Sixty-two intestinal specimens (9 isografts, 12 allografts treated with cyclosporine A [CsA], 22 untreated allografts, and 19 intestines from normal rats) were collected for in vitro transluminal US imaging (30 MHz) and histopathologic study. The echo pattern of normal rat intestinal wall consisted of five echo layers that correlated spatially with the histological layers: the innermost hyperechoic layer 1, plus hypoechoic layer 2, corresponded to the mucosa; hyperechoic layer 3, the submucosa; anechoic layer 4, the muscularis propria; and hyperechoic layer 5, the serosa. The isografts and CsA-treated allografts were identical histologically and ultrasonically to normal intestine. However, the echo patterns of the untreated allografts had progressive loss of architectural stratification, with worsening rejection. The change began with patchy indistinctness and disruption of hyperechoic layers 1, 3 and 5, and progressed to total obliteration of the layers, with the intestinal wall becoming a nonstratified hypoechoic structure.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Water Exchange Produces Significantly Higher Adenoma Detection Rate Than Water Immersion: Pooled Data From 2 Multisite Randomized Controlled Trials.

    Science.gov (United States)

    Leung, Felix W; Koo, Malcolm; Cadoni, Sergio; Falt, Premysl; Hsieh, Yu-Hsi; Amato, Arnaldo; Erriu, Matteo; Fojtik, Petr; Gallittu, Paolo; Hu, Chi-Tan; Leung, Joseph W; Liggi, Mauro; Paggi, Silvia; Radaelli, Franco; Rondonotti, Emanuele; Smajstrla, Vit; Tseng, Chih-Wei; Urban, Ondrej

    2018-03-02

    To test the hypothesis that water exchange (WE) significantly increases adenoma detection rates (ADR) compared with water immersion (WI). Low ADR was linked to increased risk for interval colorectal cancers and related deaths. Two recent randomized controlled trials of head-to-head comparison of WE, WI, and traditional air insufflation (AI) each showed that WE achieved significantly higher ADR than AI, but not WI. The data were pooled from these 2 studies to test the above hypothesis. Two trials (5 sites, 14 colonoscopists) that randomized 1875 patients 1:1:1 to AI, WI, or WE were pooled and analyzed with ADR as the primary outcome. The ADR of AI (39.5%) and WI (42.4%) were comparable, significantly lower than that of WE (49.6%) (vs. AI P=0.001; vs. WI P=0.033). WE insertion time was 3 minutes longer than that of AI (Prate (vs. AI) of the >10 mm advanced adenomas. Right colon combined advanced and sessile serrated ADR of AI (3.4%) and WI (5%) were comparable and were significantly lower than that of WE (8.5%) (vs. AI P<0.001; vs. WI P=0.039). Compared with AI and WI, the superior ADR of WE offsets the drawback of a significantly longer insertion time. For quality improvement focused on increasing adenoma detection, WE is preferred over WI. The hypothesis that WE could lower the risk of interval colorectal cancers and related deaths should be tested.

  13. Application of site and haplotype-frequency based approaches for detecting selection signatures in cattle

    Directory of Open Access Journals (Sweden)

    Moore Stephen

    2011-06-01

    Full Text Available Abstract Background 'Selection signatures' delimit regions of the genome that are, or have been, functionally important and have therefore been under either natural or artificial selection. In this study, two different and complementary methods--integrated Haplotype Homozygosity Score (|iHS| and population differentiation index (FST--were applied to identify traces of decades of intensive artificial selection for traits of economic importance in modern cattle. Results We scanned the genome of a diverse set of dairy and beef breeds from Germany, Canada and Australia genotyped with a 50 K SNP panel. Across breeds, a total of 109 extreme |iHS| values exceeded the empirical threshold level of 5% with 19, 27, 9, 10 and 17 outliers in Holstein, Brown Swiss, Australian Angus, Hereford and Simmental, respectively. Annotating the regions harboring clustered |iHS| signals revealed a panel of interesting candidate genes like SPATA17, MGAT1, PGRMC2 and ACTC1, COL23A1, MATN2, respectively, in the context of reproduction and muscle formation. In a further step, a new Bayesian FST-based approach was applied with a set of geographically separated populations including Holstein, Brown Swiss, Simmental, North American Angus and Piedmontese for detecting differentiated loci. In total, 127 regions exceeding the 2.5 per cent threshold of the empirical posterior distribution were identified as extremely differentiated. In a substantial number (56 out of 127 cases the extreme FST values were found to be positioned in poor gene content regions which deviated significantly (p ST values were found in regions of some relevant genes such as SMCP and FGF1. Conclusions Overall, 236 regions putatively subject to recent positive selection in the cattle genome were detected. Both |iHS| and FST suggested selection in the vicinity of the Sialic acid binding Ig-like lectin 5 gene on BTA18. This region was recently reported to be a major QTL with strong effects on productive life

  14. Frequency of suspected cases of neurocysticercosis detected by computed skull tomography in Santa Maria, RS, Brazil.

    Science.gov (United States)

    Silva, J E; Diefenthäler, A P; Palma, J K

    2000-01-01

    Due to the lack of studies about neurocysticercosis in the South of Brazil, an investigation was conducted to determine the percentage of suspected cases of neurocysticercosis in computed tomography diagnoses in Santa Maria, RS, from January 1997 to December 1998. Of 6300 computed tomographies (CT) of the skull performed at the private Hospital de Caridade Astrogildo de Azevedo, 80, i.e., 1.27% were suspected of neurocysticercosis. Fifty were women (62.5%) and 30 were men (37.5%). The most frequent radiological manifestation indicating neurocysticercosis was the presence of calcifications (isolated or associated), with a 95% rate (76 cases), while the presence of hypodense lesions reached a 5% rate (4 cases). After routine analysis, each CT was evaluated again and the suspected cases were confirmed. The percentage of suspected cases of neurocysticercosis detected by CT in the present study carried out in Santa Maria was considered low (1.27%). This can be explained by the fact that tomography is not accessible to the economically underprivileged population of Santa Maria. We hope that the present study can alert the population and the professionals to the fact that neurocysticercosis is a more frequent disease than indicated by the few diagnoses made.

  15. Prevalence and evolution of low frequency HIV drug resistance mutations detected by ultra deep sequencing in patients experiencing first line antiretroviral therapy failure.

    Science.gov (United States)

    Vandenhende, Marie-Anne; Bellecave, Pantxika; Recordon-Pinson, Patricia; Reigadas, Sandrine; Bidet, Yannick; Bruyand, Mathias; Bonnet, Fabrice; Lazaro, Estibaliz; Neau, Didier; Fleury, Hervé; Dabis, François; Morlat, Philippe; Masquelier, Bernard

    2014-01-01

    Clinical relevance of low-frequency HIV-1 variants carrying drug resistance associated mutations (DRMs) is still unclear. We aimed to study the prevalence of low-frequency DRMs, detected by Ultra-Deep Sequencing (UDS) before antiretroviral therapy (ART) and at virological failure (VF), in HIV-1 infected patients experiencing VF on first-line ART. Twenty-nine ART-naive patients followed up in the ANRS-CO3 Aquitaine Cohort, having initiated ART between 2000 and 2009 and experiencing VF (2 plasma viral loads (VL) >500 copies/ml or one VL >1000 copies/ml) were included. Reverse transcriptase and protease DRMs were identified using Sanger sequencing (SS) and UDS at baseline (before ART initiation) and VF. Additional low-frequency variants with PI-, NNRTI- and NRTI-DRMs were found by UDS at baseline and VF, significantly increasing the number of detected DRMs by 1.35 fold (plow-frequency DRMs modified ARV susceptibility predictions to the prescribed treatment for 1 patient at baseline, in whom low-frequency DRM was found at high frequency at VF, and 6 patients at VF. DRMs found at VF were rarely detected as low-frequency DRMs prior to treatment. The rare low-frequency NNRTI- and NRTI-DRMs detected at baseline that correlated with the prescribed treatment were most often found at high-frequency at VF. Low frequency DRMs detected before ART initiation and at VF in patients experiencing VF on first-line ART can increase the overall burden of resistance to PI, NRTI and NNRTI.

  16. Giant magnetoimpedance and high frequency electrical detection of magnetic transition in La{sub 0.75}Sr{sub 0.25}MnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Barik, S K; Rebello, A; Tan, C L; Mahendiran, R [Department of Physics, Faculty of Science, National University of Singapore 2 Science Drive 3, Singapore-117542 (Singapore)

    2008-01-21

    We show that high frequency electrical transport is an efficient technique for detecting the magnetic transition hidden by the scattering of charges at grain boundaries in colossal magnetoresistive oxides, even in the absence of any external magnetic field. The dc resistivity which shows only a weak anomaly at the Curie temperature in La{sub 0.75}Sr{sub 0.25} MnO{sub 3} transforms into abrupt jumps in both resistive (Z') and reactive (Z-prime) parts of the ac impedance, Z(f, T, H) = Z'(f, T, H) + jZ-prime(f, T, H) at higher frequencies (f = 0.1-5 MHz). The anomaly in Z' and Z-prime at T{sub C} decreases as much as 19% and 15%, respectively, in a dc magnetic field of H 65 mT compared with 1% dc magnetoresistance, suggesting a possible giant low-field magnetoimpedance effect which could be exploited for room temperature practical applications. We interpret our observations due to changes in the magnetic penetration depth induced by the spontaneous ordering of spins and by the applied field. (fast track communication)

  17. Molecular Detection of Malaria at Delivery Reveals a High Frequency of Submicroscopic Infections and Associated Placental Damage in Pregnant Women from Northwest Colombia

    Science.gov (United States)

    Arango, Eliana M.; Samuel, Roshini; Agudelo, Olga M.; Carmona-Fonseca, Jaime; Maestre, Amanda; Yanow, Stephanie K.

    2013-01-01

    Plasmodium infection in pregnancy causes substantial maternal and infant morbidity and mortality. In Colombia, both P. falciparum and P. vivax are endemic, but the impact of either species on pregnancy is largely unknown in this country. A cross-sectional study was carried out with 96 pregnant women who delivered at their local hospital. Maternal, placental, and cord blood were tested for malaria infection by microscopy and real-time quantitative polymerase chain reaction (qPCR). A high frequency of infection was detected by qPCR (45%). These infections had low concentrations of parasite DNA, and 79% were submicroscopic. Submicroscopic infections were associated with placental villitis and intervillitis. In conclusion, the overall frequency of Plasmodium infection at delivery in Colombia is much higher than previously reported. These data prompt a re-examination of the local epidemiology of malaria using molecular diagnostics to establish the clinical relevance of submicroscopic infections during pregnancy as well as their consequences for mothers and newborns. PMID:23716408

  18. Surface electromyography based muscle fatigue detection using high-resolution time-frequency methods and machine learning algorithms.

    Science.gov (United States)

    Karthick, P A; Ghosh, Diptasree Maitra; Ramakrishnan, S

    2018-02-01

    Surface electromyography (sEMG) based muscle fatigue research is widely preferred in sports science and occupational/rehabilitation studies due to its noninvasiveness. However, these signals are complex, multicomponent and highly nonstationary with large inter-subject variations, particularly during dynamic contractions. Hence, time-frequency based machine learning methodologies can improve the design of automated system for these signals. In this work, the analysis based on high-resolution time-frequency methods, namely, Stockwell transform (S-transform), B-distribution (BD) and extended modified B-distribution (EMBD) are proposed to differentiate the dynamic muscle nonfatigue and fatigue conditions. The nonfatigue and fatigue segments of sEMG signals recorded from the biceps brachii of 52 healthy volunteers are preprocessed and subjected to S-transform, BD and EMBD. Twelve features are extracted from each method and prominent features are selected using genetic algorithm (GA) and binary particle swarm optimization (BPSO). Five machine learning algorithms, namely, naïve Bayes, support vector machine (SVM) of polynomial and radial basis kernel, random forest and rotation forests are used for the classification. The results show that all the proposed time-frequency distributions (TFDs) are able to show the nonstationary variations of sEMG signals. Most of the features exhibit statistically significant difference in the muscle fatigue and nonfatigue conditions. The maximum number of features (66%) is reduced by GA and BPSO for EMBD and BD-TFD respectively. The combination of EMBD- polynomial kernel based SVM is found to be most accurate (91% accuracy) in classifying the conditions with the features selected using GA. The proposed methods are found to be capable of handling the nonstationary and multicomponent variations of sEMG signals recorded in dynamic fatiguing contractions. Particularly, the combination of EMBD- polynomial kernel based SVM could be used to

  19. Epileptic seizure detection from EEG signals with phase-amplitude cross-frequency coupling and support vector machine

    Science.gov (United States)

    Liu, Yang; Wang, Jiang; Cai, Lihui; Chen, Yingyuan; Qin, Yingmei

    2018-03-01

    As a pattern of cross-frequency coupling (CFC), phase-amplitude coupling (PAC) depicts the interaction between the phase and amplitude of distinct frequency bands from the same signal, and has been proved to be closely related to the brain’s cognitive and memory activities. This work utilized PAC and support vector machine (SVM) classifier to identify the epileptic seizures from electroencephalogram (EEG) data. The entropy-based modulation index (MI) matrixes are used to express the strength of PAC, from which we extracted features as the input for classifier. Based on the Bonn database, which contains five datasets of EEG segments obtained from healthy volunteers and epileptic subjects, a 100% classification accuracy is achieved for identifying seizure ictal from healthy data, and an accuracy of 97.67% is reached in the classification of ictal EEG signals from inter-ictal EEGs. Based on the CHB-MIT database which is a group of continuously recorded epileptic EEGs by scalp electrodes, a 97.50% classification accuracy is obtained and a raising sign of MI value is found at 6s before seizure onset. The classification performance in this work is effective, and PAC can be considered as a useful tool for detecting and predicting the epileptic seizures and providing reference for clinical diagnosis.

  20. Exploring the performance of thin-film superconducting multilayers as kinetic inductance detectors for low-frequency detection

    Science.gov (United States)

    Zhao, Songyuan; Goldie, D. J.; Withington, S.; Thomas, C. N.

    2018-01-01

    We have solved numerically the diffusive Usadel equations that describe the spatially varying superconducting proximity effect in Ti-Al thin-film bi- and trilayers with thickness values that are suitable for kinetic inductance detectors (KIDs) to operate as photon detectors with detection thresholds in the frequency range of 50-90 GHz. Using Nam’s extension of the Mattis-Bardeen calculation of the superconductor complex conductivity, we show how to calculate the surface impedance for the spatially varying case, and hence the surface impedance quality factor. In addition, we calculate energy-and spatially-averaged quasiparticle lifetimes at temperatures well-below the transition temperature and compare to calculation in Al. Our results for the pair-breaking threshold demonstrate differences between bilayers and trilayers with the same total film thicknesses. We also predict high quality factors and long multilayer-averaged quasiparticle recombination times compared to thin-film Al. Our calculations give a route for designing KIDs to operate in this scientifically-important frequency regime.

  1. A Quadrature-Based Tunable Radio-Frequency Sensor for the Detection and Analysis of Aqueous Solutions.

    Science.gov (United States)

    Cui, Yan; He, Yuxi; Wang, Pingshan

    2014-07-01

    A highly tunable and sensitive radio-frequency (RF) sensor is presented for the measurement of aqueous-solution dielectric properties. Two quadrature hybrids are utilized to achieve destructive interference that eliminates the probing signals at both measurement ports. As a result, weak signals of material-under-test (MUT) are elevated for high sensitivity detections at different frequencies. The sensor is demonstrated through measuring 2-propanol-water solution permittivity at 0.01 mole fraction concentration level from ~4 GHz to ~12 GHz. De-ionized water and methanol-water solution are used to calibrate the sensor for quantitative MUT analysis through our proposed model. Micro-meter coplanar waveguides (CPW) are fabricated as RF sensing electrodes. A polydimethylsiloxane (PDMS) microfluidic channel is employed to introduce 250 nL liquid, of which ~1 nL is effectively the MUT. The permittivity and the relaxation time of 2-propanol-water solution are obtained. Compared with our power divider based sensors, the differential reflection coefficients in this work provide additional information that complements the transmission coefficient methods.

  2. DETECTION OF MENDELIAN AND GENOTYPE FREQUENCY OF GROWTH HORMONE GENE IN ONGOLE CROSSBRED CATTLE MATED BY THE ARTIFICIAL INSEMINATION TECHNIQUE

    Directory of Open Access Journals (Sweden)

    U. Paputungan

    2012-06-01

    Full Text Available The objectives of this study were to detect the Mendelian mode inheritance of growth hormone (GH and to establish genotype frequency of GH gene in Ongole-crossbred cattle mated by the artificial insemination (AI technique. Total of 76 blood samples were collected from Ongole-crossbred cows and bulls (G0, and their progenies (G1 at the Tumaratas AI service center in North Sulawesi province, Indonesia. All blood samples were screened for the presence of GH locus using a PCR-RFLP method involving restricted enzyme Msp1 on 1.2 % of agarose gel. Data were analyzed using statistical program function in Excel XP. The results showed that GH locus using alleles of Msp1+ and Msp1- enzyme restriction in Ongole-crossbred cows and bulls was inherited to their Ongole-crossbred progenies following the Mendelian mode inheritance. This Mendelian inheritance generated by AI technique was not under genetic equilibrium for the Msp1 genotype frequencies in groups of G0 and G1. The breeding program using genotypes of bulls and cows (G0 for generating the genotype of GH Msp1 enzyme restriction by AI technique should be maintained to increase these various allele dispersion rates for breeding under genetic equilibrium of the Ongole-crossbred cattle population.

  3. The frequency of genotypes for the SNP Ser/Ser in the studied population of Albanian women is higher in the Balkan region

    Directory of Open Access Journals (Sweden)

    Zafer Gashi

    2016-08-01

    Full Text Available In women undergoing natural cycles, just one oocyte is usually selected for ovulation, yet routine clinical techniques to support the development of multiple follicles using additional gonadotrophins result in numerous ovulations. Several parameters have been postulated as predictors of ovarian response (inhibin B, 17-β-estradiol and antiMüllerian hormone. Nevertheless, the FSH level on the day 3 of menstrual cycle remains, the most widely used biomarker due to its low cost, although, the genetic background of individuals seems to determine the response of patients to rFSH stimulation better than the stimulation design. Consequently, the variants of FSHR were explored and they may be involved in the role of FSH receptor in mediated signal transduction and with ovarian response in infertile women submitted to ovarian stimulation. In this study we examined, for the first time, the prevalence of genotype variants Asn680Ser in population Albanian women from Kosovo Dukagjin region who took part in IVF / ICSI program. The frequencies of the Asn680Ser genotype variants were as follows: Asn/Asn 22.1%, Asn/Ser 47.1%, and Ser/Ser 30.8%, respectively (Table 1. bE2 levels between the three genotype variants showed slight but statistically significant difference (p= 0.0308. No difference was also found between the genotype groups either in terms of AFC, amount of the FSH required for ovulation induction, stimulation length days, number of dominant follicles, oocyte retrieval number or endometrial thickness (Table 2. BMI was significantly higher in the Ser/Ser group as compared to those from the Asn/Ser or the Asn/Asn group (p= 0.0010 (Table 2. In the study population of Albanian women Dukagjin region of Kosovo had a higher incidence of Ser / SER genotype compared to Asn / Asn genotype. Our research results in the Albanian population differ from published data for other ethnic groups in the Balkans.

  4. Frequency and Clinical Implication of the R450H Mutation in the Thyrotropin Receptor Gene in the Japanese Population Detected by Smart Amplification Process 2

    Science.gov (United States)

    Yanagawa, Yoshimaro; Aoki, Tomoyuki; Morimura, Tadashi; Araki, Osamu; Kimura, Takao; Ogiwara, Takayuki; Kotajima, Nobuo; Yanagawa, Masumi; Murakami, Masami

    2014-01-01

    In Japanese pediatric patients with thyrotropin (TSH) resistance, the R450H mutation in TSH receptor gene (TSHR) is occasionally observed. We studied the frequency and clinical implication of the R450H mutation in TSHR in the general population of Japanese adults using smart amplification process 2 (SmartAmp2). We designed SmartAmp2 primer sets to detect this mutation using a drop of whole blood. We analyzed thyroid function, antithyroid antibodies, and this mutation in 429 Japanese participants who had not been found to have thyroid disease. Two cases without antithyroid antibodies were heterozygous for the R450H mutation in TSHR. Thus, the prevalence of this mutation was 0.47% in the general population and 0.63% among those without antithyroid antibodies. Their serum TSH concentrations were higher than the average TSH concentration not only in subjects without antithyroid antibodies but also in those with antithyroid antibodies. The R450H mutation in TSHR is relatively common in the Japanese population and potentially affects thyroid function. The present study demonstrates that the SmartAmp2 method is useful to detect the R450H mutation in TSHR, which is one of the common causes of TSH resistance in the Japanese population. PMID:24895636

  5. Detection and characterization of benthic filamentous algal stands (Cladophora sp.) on rocky substrata using a high-frequency echosounder

    Science.gov (United States)

    Depew, David C.; Stevens, Andrew W.; Smith, Ralph E.H.; Hecky, Robert E.

    2009-01-01

    A high-frequency echosounder was used to detect and characterize percent cover and stand height of the benthic filamentous green alga Cladophora sp. on rocky substratum of the Laurentian Great Lakes. Comparisons between in situ observations and estimates of the algal stand characteristics (percent cover, stand height) derived from the acoustic data show good agreement for algal stands that exceeded the height threshold for detection by acoustics (~7.5 cm). Backscatter intensity and volume scattering strength were unable to provide any predictive power for estimating algal biomass. A comparative analysis between the only current commercial software (EcoSAV™) and an alternate method using a graphical user interface (GUI) written in MATLAB® confirmed previous findings that EcoSAV functions poorly in conditions where the substrate is uneven and bottom depth changes rapidly. The GUI method uses a signal processing algorithm similar to that of EcoSAV but bases bottom depth classification and algal stand height classification on adjustable thresholds that can be visualized by a trained analyst. This study documents the successful characterization of nuisance quantities of filamentous algae on hard substrate using an acoustic system and demonstrates the potential to significantly increase the efficiency of collecting information on the distribution of nuisance macroalgae. This study also highlights the need for further development of more flexible classification algorithms that can be used in a variety of aquatic ecosystems.

  6. High frequency of human papillomavirus detection in the vagina before first vaginal intercourse among females enrolled in a longitudinal cohort study.

    Science.gov (United States)

    Shew, Marcia L; Weaver, Bree; Tu, Wanzhu; Tong, Yan; Fortenberry, J Dennis; Brown, Darron R

    2013-03-15

    Genital human papillomavirus (HPV) infection is believed to be primarily sexually transmitted. Few studies have documented the detection of HPV in the vagina before first vaginal intercourse. We used a longitudinally followed cohort of adolescent females without prior vaginal intercourse to examine the frequency of detection of vaginal HPV and the association between first reported HPV detection and noncoital sexual behaviors. HPV was detected in 45.5% of subjects (10 of 22) before first vaginal sex. Seven of these 10 subjects reported noncoital behaviors that, in part, might have explained genital transmission. HPV can be detected in the vagina before first sexual intercourse, highlighting the need for early vaccination.

  7. Ureaplasma parvum and Ureaplasma urealyticum detected with the same frequency among women with and without symptoms of urogenital tract infection.

    Science.gov (United States)

    Marovt, M; Keše, D; Kotar, T; Kmet, N; Miljković, J; Šoba, B; Matičič, M

    2015-06-01

    There is mounting evidence stating that Ureaplasma urealyticum causes non-gonococcal urethritis in males, whereas Ureaplasma parvum does not seem to be of clinical significance. However, the clinical role of U. parvum and U. urealyticum in lower urogenital tract infections in females remains unclear. The aim of the study was to determine the frequency of U. parvum and U. urealyticum among 145 Ureaplasma spp. culture-positive women with symptoms of lower urogenital tract infection (n = 75) and those without (n = 70), and to determine possible associations between the detection of U. parvum and U. urealyticum with selected characteristics. Endocervical, urethral, and vaginal swabs, and first voided urine were obtained. Polymerase chain reaction (PCR) was performed to differentiate ureaplasmas. No significant association between the detection of U. parvum or U. urealyticum and symptom status was found. Significantly more women aged 25 years and younger were infected with U. urealyticum (23.4 %) compared to those aged above 25 years (9.2 %) [odds ratio (OR) 3.0 (1.1; 8.1); p = 0.03] and significantly less women aged 25 years and younger (83.5 %) were infected with U. parvum compared to those aged above 25 years (95.5 %) [OR 0.2 (0.1; 0.9); p = 0.03]. The detection of Chlamydia trachomatis was significantly associated to both U. parvum and U. urealyticum (p = 0.021), and to U. parvum alone with borderline significance (p = 0.063). Although neither U. parvum nor U. urealyticum seem to cause symptoms in females, their role in the female urogenital tract remains unknown, taking into account their ubiquity, possible augmentation of the urogenital microenvironment, and ascending capability to the sterile upper reproductive tract.

  8. Lack of evidence of HPV etiology of prostate cancer following radical surgery and higher frequency of the Arg/Pro genotype in turkish men with prostate cancer

    Directory of Open Access Journals (Sweden)

    Merve Aydin

    Full Text Available ABSTRACT Objectives The aim of this study was to assess the possible role of HPV in the development of prostate cancer (PCa and investigate the distribution of the p53 codon 72 polymorphism in PCa in a Turkish population. Materials and methods A total of 96 tissues, which had been obtained using a radical surgery method, formalin-fixed and parafin-embedded, were used in this study. The study group consisted of 60 PCa tissues (open radical prostatectomy and the control group contained 36 benign prostatic hyperplasia tissues (BPH (transvesical open prostatectomy. The presence of HPV and the p53 codon 72 polymorphism was investigated in both groups using real-time PCR and pyrosequencing. Results The results of the real-time PCR showed no HPV DNA in any of the 36 BPH tissue samples. HPV-DNA was positive in only 1 of the 60 PCa samples (1.7%. The HPV type of this sample was identified as HPV-57. The distribution of the three genotypes, Arg/Arg, Arg/Pro and Pro/Pro was found to be 45.6, 45.6, and 8.8% in the PCa group and 57.1%, 34.3% and 8.6% in the control group, respectively. Compared with the control group, patients with PCa had a higher frequency of the Arg/Pro genotype and Proline allele (odds ratio (OR=1.67, 95% confidence interval (CI=0.68-4.09, p=0.044; OR=1.13, 95% CI=0.76-1.68, p=0.021, respectively. Conclusions The results of the study do not support the hyphothesis that prostate cancer is associated with HPV infection but indicated that Proline allele can be a risk factor in the development of PCa in the Turkish population.

  9. Multi-probe-based resonance-frequency electrical impedance spectroscopy for detection of suspicious breast lesions: improving performance using partial ROC optimization

    Science.gov (United States)

    Lederman, Dror; Zheng, Bin; Wang, Xingwei; Wang, Xiao Hui; Gur, David

    2011-03-01

    We have developed a multi-probe resonance-frequency electrical impedance spectroscope (REIS) system to detect breast abnormalities. Based on assessing asymmetry in REIS signals acquired between left and right breasts, we developed several machine learning classifiers to classify younger women (i.e., under 50YO) into two groups of having high and low risk for developing breast cancer. In this study, we investigated a new method to optimize performance based on the area under a selected partial receiver operating characteristic (ROC) curve when optimizing an artificial neural network (ANN), and tested whether it could improve classification performance. From an ongoing prospective study, we selected a dataset of 174 cases for whom we have both REIS signals and diagnostic status verification. The dataset includes 66 "positive" cases recommended for biopsy due to detection of highly suspicious breast lesions and 108 "negative" cases determined by imaging based examinations. A set of REIS-based feature differences, extracted from the two breasts using a mirror-matched approach, was computed and constituted an initial feature pool. Using a leave-one-case-out cross-validation method, we applied a genetic algorithm (GA) to train the ANN with an optimal subset of features. Two optimization criteria were separately used in GA optimization, namely the area under the entire ROC curve (AUC) and the partial area under the ROC curve, up to a predetermined threshold (i.e., 90% specificity). The results showed that although the ANN optimized using the entire AUC yielded higher overall performance (AUC = 0.83 versus 0.76), the ANN optimized using the partial ROC area criterion achieved substantially higher operational performance (i.e., increasing sensitivity level from 28% to 48% at 95% specificity and/ or from 48% to 58% at 90% specificity).

  10. Detection and Classification of Low Probability of Intercept Radar Signals Using Parallel Filter Arrays and Higher Order Statistics

    National Research Council Canada - National Science Library

    Taboada, Fernando

    2002-01-01

    ... intercept devices such as radar warning, electronic support and electronic intelligence receivers, In order to detect LPI radar waveforms new signal processing techniques are required This thesis first...

  11. Higher Physiotherapy Frequency Is Associated with Shorter Length of Stay and Greater Functional Recovery in Hospitalized Frail Older Adults: A Retrospective Observational Study.

    Science.gov (United States)

    Hartley, P; Adamson, J; Cunningham, C; Embleton, G; Romero-Ortuno, R

    2016-01-01

    Extra physiotherapy has been associated with better outcomes in hospitalized patients, but this remains an under-researched area in geriatric medicine wards. We retrospectively studied the association between average physiotherapy frequency and outcomes in hospitalized geriatric patients. High frequency physiotherapy (HFP) was defined as ≥0.5 contacts/day. Of 358 eligible patients, 131 (36.6%) received low, and 227 (63.4%) HFP. Functional improvement (discharge versus admission) in the modified Rankin scale was greater in the HFP group (1.1 versus 0.7 points, Pphysiotherapy frequency and intensity in geriatric wards.

  12. Radio-frequency surgical sponge detection: a new way to lower the odds of leaving sponges (and similar items) in patients.

    Science.gov (United States)

    2008-07-01

    Radio-frequency (RF) tags are now being embedded in items such as surgical sponges, towels, and pads to reduce the chances that these objects will be left in patients after a procedure. Find out how--and how well--RF sponge-detection systems work, including our view of the two systems currently on the market: ClearCount Medical's SmartSponge System, which counts sponges in addition to detecting them. RF Surgical's RF Surgical Detection System, which is a detect-only system.

  13. Higher physiotherapy frequency is associated with shorter length of stay and greater functional recovery in hospitalized frail older adults: a retrospective observational study

    OpenAIRE

    Hartley, Peter; Adamson, Jennifer; Cunningham, Carol; Embleton, Georgina; Romero-Ortuno, Roman

    2016-01-01

    Extra physiotherapy has been associated with better outcomes in hospitalized patients, but this remains an under-researched area in geriatric medicine wards. We retrospectively studied the association between average physiotherapy frequency and outcomes in hospitalized geriatric patients. High frequency physiotherapy (HFP) was defined as ≥0.5 contacts/day. Of 358 eligible patients, 131 (36.6%) received low, and 227 (63.4%) HFP. Functional improvement (discharge versus admission) in the modifi...

  14. Three-Dimensional High-Frequency Ultrasonography for Early Detection and Characterization of Embryo Implantation Site Development in the Mouse.

    Directory of Open Access Journals (Sweden)

    Mary C Peavey

    Full Text Available Ultrasonography is a powerful tool to non-invasively monitor in real time the development of the human fetus in utero. Although genetically engineered mice have served as valuable in vivo models to study both embryo implantation and pregnancy progression, such studies usually require sacrifice of parous mice for subsequent phenotypic analysis. To address this issue, we used three-dimensional (3-D reconstruction in silico of high-frequency ultrasound (HFUS imaging data for early detection and characterization of murine embryo implantation sites and their development in utero. With HFUS imaging followed by 3-D reconstruction, we were able to precisely quantify embryo implantation site number and embryonic developmental progression in pregnant C57BL6J/129S mice from as early as 5.5 days post coitus (d.p.c. through to 9.5 d.p.c. using a VisualSonics Vevo 2100 (MS550S transducer. In addition to measurements of implantation site number, location, volume and spacing, embryo viability via cardiac activity monitoring was also achieved. A total of 12 dams were imaged with HFUS with approximately 100 embryos examined per embryonic day. For the post-implantation period (5.5 to 8.5 d.p.c., 3-D reconstruction of the gravid uterus in mesh or solid overlay format enabled visual representation in silico of implantation site location, number, spacing distances, and site volume within each uterine horn. Therefore, this short technical report describes the feasibility of using 3-D HFUS imaging for early detection and analysis of post-implantation events in the pregnant mouse with the ability to longitudinally monitor the development of these early pregnancy events in a non-invasive manner. As genetically engineered mice continue to be used to characterize female reproductive phenotypes, we believe this reliable and non-invasive method to detect, quantify, and characterize early implantation events will prove to be an invaluable investigative tool for the study of

  15. Detection of superparamagnetic particles in soils developed on basalts using frequency- and amplitude-dependent magnetic susceptibility

    Science.gov (United States)

    Grison, H.; Petrovsky, E.; Kapicka, A.

    2016-12-01

    In rock, soil and environmental studies dealing with magnetic methods, the frequency-dependent magnetic susceptibility (κFD%) is parameter generally accepted as a tool for identification of ultrafine superparamagnetic (SP) particles. This parameter became an indicator of pedogenic magnetic fraction (increased pedogenesis). Despite the number of studies using this parameter, knowledge about threshold values of κFD% is not clear enough and this parameter may be misinterpreted. Moreover, in strongly magnetic soils, magnetic signal of the SP (mostly pedogenic) minerals may be masked by dominant lithological signal, carried by coarse-grain mineral fraction; therefore, influence of pedogenesis is hard to detect. The aim of this contribution is to compare results in determination of ultrafine SP magnetic particles in soils determined using different instruments: (a) Bartington MS2B dual-frequency meter, and (b) more sensitive AGICO Kappameter MFK1-FA. The values of the κFD % obtained by the Bartington MS2B varied from 0.9 to 5.8% (mass-specific magnetic susceptibility from 119 to 1533 × 10-8 m3/kg) while the AGICO MFK1-FA varied from 3.7 to 8.2% (mass-specific magnetic susceptibility from 295 to 1843 × 10-8 m3/kg). Although both instruments suggest significant portion of SP magnetic particles, the results can't be interpreted using the generally accepted threshold values based on Bartington data. However, our results suggest that relation between the mass-specific magnetic susceptibility and κFD% along whole soil profile may serve as suitable tool in discriminating between lithogenic and pedogenic control of magnetic fraction in the soil profile. Moreover, we propose new concept of identification of SP particles, based on field-dependent magnetic susceptibility. Its behaviour shows distinct features with significant change at amplitudes of about 100 A/m. Below this value, susceptibility decreases with increasing amplitude, reflecting saturation of magnetization due

  16. Physiologic Waveform Analysis for Early Detection of Hemorrhage during Transport and Higher Echelon Medical Care of Combat Casualties

    Science.gov (United States)

    2014-03-01

    area under the curve (ROC AUC ) values. (ROC AUC values range from 0 and 1 and indicate the probability of correct detection/discrimination...training set of the human LBNP data. Values are receiver operating characteristic area under the curves (ROC AUCs ) comparing the relative SV change...detection of hemorrhage is crucial for managing combat casualties. However, mean arterial blood pressure (ABP) and other vital signs are late indicators of

  17. Gap Detection in School-Age Children and Adults: Effects of Inherent Envelope Modulation and the Availability of Cues across Frequency

    Science.gov (United States)

    Buss, Emily; Hall, Joseph W., III; Porter, Heather; Grose, John H.

    2014-01-01

    Purpose: The present study evaluated the effects of inherent envelope modulation and the availability of cues across frequency on behavioral gap detection with noise-band stimuli in school-age children. Method: Listeners were 34 normal-hearing children (ages 5.2-15.6 years) and 12 normal-hearing adults (ages 18.5-28.8 years). Stimuli were…

  18. Detection of small-amplitude periodic surface pressure fluctuation by pressure-sensitive paint measurements using frequency-domain methods

    Science.gov (United States)

    Noda, Takahiro; Nakakita, Kazuyki; Wakahara, Masaki; Kameda, Masaharu

    2018-06-01

    Image measurement using pressure-sensitive paint (PSP) is an effective tool for analyzing the unsteady pressure field on the surface of a body in a low-speed air flow, which is associated with wind noise. In this study, the surface pressure fluctuation due to the tonal trailing edge (TE) noise for a two-dimensional NACA 0012 airfoil was quantitatively detected using a porous anodized aluminum PSP (AA-PSP). The emission from the PSP upon illumination by a blue laser diode was captured using a 12-bit high-speed complementary metal-oxide-semiconductor (CMOS) camera. The intensities of the captured images were converted to pressures using a standard intensity-based method. Three image-processing methods based on the fast Fourier transform (FFT) were tested to determine their efficiency in improving the signal-to-noise ratio (SNR) of the unsteady PSP data. In addition to two fundamental FFT techniques (the full data and ensemble averaging FFTs), a technique using the coherent output power (COP), which involves the cross correlation between the PSP data and the signal measured using a pointwise sound-level meter, was tested. Preliminary tests indicated that random photon shot noise dominates the intensity fluctuations in the captured PSP emissions above 200 Hz. Pressure fluctuations associated with the TE noise, whose dominant frequency is approximately 940 Hz, were successfully measured by analyzing 40,960 sequential PSP images recorded at 10 kfps. Quantitative validation using the power spectrum indicates that the COP technique is the most effective method of identification of the pressure fluctuation directly related to TE noise. It is possible to distinguish power differences with a resolution of 10 Pa^2 (4 Pa in amplitude) when the COP was employed without use of another wind-off data. This resolution cannot be achieved by the ensemble averaging FFT because of an insufficient elimination of the background noise.

  19. [Toxocara canis: frequency of detection and extent of infection in bitches of various breeds and husbandry and their litters in South Germany].

    Science.gov (United States)

    Gothe, R; Reichler, I

    1990-06-01

    Epidemiological investigations of 100 randomly selected dog families in Southern Germany revealed eggs of Toxocara canis in 67% of the litters and in 45% of the bitches. Eggs were isolated from litters at the earliest on the 16th day and at the latest on the 55th day post partum, in bitches on the 19th and 60th day respectively after giving birth. With regard to the coproscopically detected frequency of T. canis eggs in separate analyses of the dog breeds, only slight differences were found; very large breeds, however, revealed substantially a greater excretion extent. An evaluation exclusively concerned with the way the dog families were kept showed a higher percentage of 76.2% for litters from kennels than among those kept indoors, which amounted only to 51.4%. Relating the excretion extent to the number of additionally kept fully grown dogs/breeder, evident correlations were found, as the number of positive litters increased together with the number of additionally kept adult dogs/dog family. In comparison with dog families exclusively kept indoors, kennel dogs had a higher extent of excretion. Regarding the number of litters born per year/stock compared with excretion extent a positive correlation could be drawn for dog families up to 5 litters/year only. The number of litters born per bitch had no influence on the excretion extent of the litters. Correlations between the number of anthelminthic treatments of litters or bitches during and following pregnancy and the excretion extent of T. canis could not be deduced. The litters remained positive even after 5-8 treatments during the investigation period of 9 weeks and positive results continued after the puppies had been sold.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Low Frequency Waves Detected in a Large Wave Flume under Irregular Waves with Different Grouping Factor and Combination of Regular Waves

    Directory of Open Access Journals (Sweden)

    Luigia Riefolo

    2018-02-01

    Full Text Available This paper describes a set of experiments undertaken at Universitat Politècnica de Catalunya in the large wave flume of the Maritime Engineering Laboratory. The purpose of this study is to highlight the effects of wave grouping and long-wave short-wave combinations regimes on low frequency generations. An eigen-value decomposition has been performed to discriminate low frequencies. In particular, measured eigen modes, determined through the spectral analysis, have been compared with calculated modes by means of eigen analysis. The low frequencies detection appears to confirm the dependence on groupiness of the modal amplitudes generated in the wave flume. Some evidence of the influence of low frequency waves on runup and transport patterns are shown. In particular, the generation and evolution of secondary bedforms are consistent with energy transferred between the standing wave modes.

  1. Equivalence of Linear MMSE Detection in DS-CDMA and MC-CDMA Systems over Time and Frequency Selective Channels

    Directory of Open Access Journals (Sweden)

    Tamer A. Kadous

    2003-01-01

    Full Text Available The goal of this paper is to compare the performance of the linear minimum mean square error (MMSE detector for a class of code division multiple access (CDMA systems in time and frequency selective channels. Specifically, we consider direct sequence (DS-CDMA, multicarrier (MC-CDMA, and the MC-DS-CDMA systems. Two key tools are used in our development. First, a general time-frequency framework that includes the different CDMA systems as special cases. Second, the duality between time and frequency domains that is used to derive equivalences between the different CDMA systems operating over purely frequency selective and purely time selective channels. We then combine the insights obtained from these special cases to assess the performance of CDMA systems over time and frequency selective channels. We provide sufficient conditions for the codes employed by the CDMA systems for the equivalences to hold. Numerical results are presented to illustrate the results.

  2. A New Real-Time Cycle Slip Detection and Repair Method under High Ionospheric Activity for a Triple-Frequency GPS/BDS Receiver.

    Science.gov (United States)

    Liu, Wanke; Jin, Xueyuan; Wu, Mingkui; Hu, Jie; Wu, Yun

    2018-02-01

    Cycle slip detection and repair is a prerequisite for high-precision global navigation satellite system (GNSS)-based positioning. With the modernization and development of GNSS systems, more satellites are available to transmit triple-frequency signals, which allows the introduction of additional linear combinations and provides new opportunities for cycle slip detection and repair. In this paper, we present a new real-time cycle slip detection and repair method under high ionospheric activity for undifferenced Global Positioning System (GPS)/BeiDou Navigation Satellite System (BDS) triple-frequency observations collected with a single receiver. First, three optimal linearly independent geometry-free pseudorange minus phase combinations are selected to correctly and uniquely determine the cycle slips on the original triple-frequency carrier phase observations. Then, a second-order time-difference algorithm is employed for the pseudorange minus phase combinations to mitigate the impact of between-epoch ionospheric residuals on cycle slip detection, which is especially beneficial under high ionospheric activity. The performance of the approach is verified with static GPS/BDS triple-frequency observations that are collected with a 30 s sampling interval under active ionospheric conditions, and observations are manually inserted with simulated cycle slips. The results show that the method can correctly detect and repair cycle slips at a resolution as small as 1 cycle. Moreover, kinematic data collected from car-driven and airborne experiments are also processed to verify the performance of the method. The experimental results also demonstrate that the method is effective in processing kinematic data.

  3. Use of AUDIT, and measures of drinking frequency and patterns to detect associations between alcohol and sexual behaviour in male sex workers in Kenya

    Directory of Open Access Journals (Sweden)

    Temmerman Marleen

    2011-05-01

    Full Text Available Abstract Background Previous research has linked alcohol use with an increased number of sexual partners, inconsistent condom use and a raised incidence of sexually transmitted infections (STIs. However, alcohol measures have been poorly standardised, with many ill-suited to eliciting, with adequate precision, the relationship between alcohol use and sexual risk behaviour. This study investigates which alcohol indicator - single-item measures of frequency and patterns of drinking ( > = 6 drinks on 1 occasion, or the Alcohol Use Disorders Identification Test (AUDIT - can detect associations between alcohol use and unsafe sexual behaviour among male sex workers. Methods A cross-sectional survey in 2008 recruited male sex workers who sell sex to men from 65 venues in Mombasa district, Kenya, similar to a 2006 survey. Information was collected on socio-demographics, substance use, sexual behaviour, violence and STI symptoms. Multivariate models examined associations between the three measures of alcohol use and condom use, sexual violence, and penile or anal discharge. Results The 442 participants reported a median 2 clients/week (IQR = 1-3, with half using condoms consistently in the last 30 days. Of the approximately 70% of men who drink alcohol, half (50.5% drink two or more times a week. Binge drinking was common (38.9%. As defined by AUDIT, 35% of participants who drink had hazardous drinking, 15% harmful drinking and 21% alcohol dependence. Compared with abstinence, alcohol dependence was associated with inconsistent condom use (AOR = 2.5, 95%CI = 1.3-4.6, penile or anal discharge (AOR = 1.9, 95%CI = 1.0-3.8, and two-fold higher odds of sexual violence (AOR = 2.0, 95%CI = 0.9-4.9. Frequent drinking was associated with inconsistent condom use (AOR = 1.8, 95%CI = 1.1-3.0 and partner number, while binge drinking was only linked with inconsistent condom use (AOR = 1.6, 95%CI = 1.0-2.5. Conclusions Male sex workers have high levels of hazardous and

  4. Remote detection of electronic devices

    Science.gov (United States)

    Judd, Stephen L [Los Alamos, NM; Fortgang, Clifford M [Los Alamos, NM; Guenther, David C [Los Alamos, NM

    2012-09-25

    An apparatus and method for detecting solid-state electronic devices are described. Non-linear junction detection techniques are combined with spread-spectrum encoding and cross correlation to increase the range and sensitivity of the non-linear junction detection and to permit the determination of the distances of the detected electronics. Nonlinear elements are detected by transmitting a signal at a chosen frequency and detecting higher harmonic signals that are returned from responding devices.

  5. Effects of higher-coordination shells in garnets detected by XAS at the Al K-edge

    International Nuclear Information System (INIS)

    Marcelli, A.; Wu, Z.; Mottana, A.; Giuli, G.; Paris, E.; Seifert, F.

    1996-03-01

    The aluminium 1 s x-ray-absorption spectra of a series of garnets, pyrope, almandine, spessartine and grossular, are compared to full multiple-scattering calculation using cluster models. An overall good agreement between experiment and calculation, extended also to the edge region,is obtained in the energy range in up to 60 e V above the threshold, provided cluster containing at least 40 atoms are used. The analysis of these garnet XAS spectra provides clear evidence on the effect of probe, XANES spectroscopy at the edge of low Z elements appears to be a perfect tool to investigate the role played by atoms located in higher-coordination shells

  6. Effects of higher-coordination shells in garnets detected by XAS at the Al K-edge

    Energy Technology Data Exchange (ETDEWEB)

    Marcelli, A. [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati; Wu, Z. [CNRS UMR 110, Laboratoire de Chimie des Solides, Nantes Cedex (France). Institut de materiaux de Nantes; Mottana, A. [Roma III Univ., Rome (Italy). Dipartimento di Scienze Geologiche; Giuli, G.; Paris, E. [Camerino Univ., Camerino (Italy).Diparimento di Scienze della Terra; Seifert, F [Univ. Bayreuth, Bayreuth (Italy). Bayerisches Geoinstitut (Germany)

    1996-03-01

    The aluminium 1 s x-ray-absorption spectra of a series of garnets, pyrope, almandine, spessartine and grossular, are compared to full multiple-scattering calculation using cluster models. An overall good agreement between experiment and calculation, extended also to the edge region,is obtained in the energy range in up to 60 e V above the threshold, provided cluster containing at least 40 atoms are used. The analysis of these garnet XAS spectra provides clear evidence on the effect of probe, XANES spectroscopy at the edge of low Z elements appears to be a perfect tool to investigate the role played by atoms located in higher-coordination shells.

  7. A diode-laser optical frequency standard based on laser-cooled Ca atoms: sub-kilohertz spectroscopy by optical shelving detection

    International Nuclear Information System (INIS)

    Oates, C.W.; Bondu, F.; Fox, R.W.; Hollberg, L.

    1999-01-01

    We report an optical frequency standard at 657 nm based on laser-cooled/trapped Ca atoms. The system consists of a novel, compact magneto-optic trap which uses 50 mW of frequency-doubled diode laser light at 423 nm and can trap >10 7 Ca atoms in 20 ms. High resolution spectroscopy on this atomic sample using the narrow 657 nm intercombination line resolves linewidths (FWHM) as narrow as 400 Hz, the natural linewidth of the transition. The spectroscopic signal-to-noise ratio is enhanced by an order of magnitude with the implementation of a ''shelving'' detection scheme on the 423 nm transition. Our present apparatus achieves a fractional frequency instability of 5 x 10 -14 in 1 s with a potential atom shot-noise-limited performance of 10 -16 τ -1/2 and excellent prospects for high accuracy. (orig.)

  8. An intuitive method to automatically detect the common and not common frequencies for two or more time-varying signals

    International Nuclear Information System (INIS)

    Doca, C.; Paunoiu, C.; Doca, L.

    2013-01-01

    Sampling a time-varying signal and his spectral analysis are, both, subjected to theoretically compelling, such as Shannon's theorem and the objectively limiting of the frequencys resolution. After obtaining the signals (Fourier) spectrum, this is processed and interpreted usually by a scientist who, presumably, has sufficient prior information about the monitored signal to conclude, for example, on the significant frequencies. Obviously, processing and interpretation of individual spectra are routine tasks that can be automated by suitable software (PC application). The problems complicate if we need to compare two or more spectra corresponding to different signals and/or phenomena. In the above context, this paper presents an intuitive method for automatic identification of the common and not common frequencies for two or more congruent spectra. The method is illustrated by numerical simulations, and by the results obtained in the analysis of the noise from some experimental measured signals. (authors)

  9. Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications

    International Nuclear Information System (INIS)

    Morawski, Ireneusz; Spiegelberg, Richard; Korte, Stefan; Voigtländer, Bert

    2015-01-01

    A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. The high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations

  10. Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications

    Energy Technology Data Exchange (ETDEWEB)

    Morawski, Ireneusz [Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich (Germany); Institute of Experimental Physics, University of Wrocław, pl. M. Borna 9, 50-204 Wrocław (Poland); Spiegelberg, Richard; Korte, Stefan; Voigtländer, Bert [Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich (Germany)

    2015-12-15

    A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. The high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations.

  11. Quantifying detection performance of a passive low-frequency RFID system in an environmental preference chamber for laying hens

    Science.gov (United States)

    Radio Frequency Identification (RFID) systems have been widely used in production livestock systems for identifying, tracing, and registering animals and improving subsidy management. Adaptations have been made to extend RFID technology to animal behavior and welfare research. An RFID system was imp...

  12. Probing the negative permittivity perfect lens at optical frequencies using near-field optics and single molecule detection

    NARCIS (Netherlands)

    Moerland, R.J.; van Hulst, N.F.; Gersen, H.; Kuipers, L.

    2005-01-01

    Recently, the existence of a perfect lens has been predicted, made of an artificial material that has a negative electric permittivity and a negative magnetic permeability. For optical frequencies a poormans version is predicted to exist in the sub-wavelength limit. Then, only the permittivity has

  13. High frequency microphone measurements for transition detection on airfoils. Risø C2-18 appendix report

    DEFF Research Database (Denmark)

    Døssing, Mads

    Time series of pressure fluctuations has been obtained using high frequency microphones distributed over the surface of airfoils undergoing wind tunnel tests in the LM Windtunnel, owned by ’LM Glasfiber’, Denmark. The present report describes the dataanalysis, with special attention given to tran...

  14. High frequency microphone measurements for transition detection on airfoils. Risø B1-18 appendix report

    DEFF Research Database (Denmark)

    Døssing, Mads

    Time series of pressure fluctuations has been obtained using high frequency microphones distributed over the surface of airfoils undergoing wind tunnel tests in the LM Windtunnel, owned by ’LM Glasfiber’, Denmark. The present report describes the dataanalysis, with special attention given to tran...

  15. Response-only method for damage detection of beam-like structures using high accuracy frequencies with auxiliary mass spatial probing

    Science.gov (United States)

    Zhong, Shuncong; Oyadiji, S. Olutunde; Ding, Kang

    2008-04-01

    This paper proposes a new approach based on auxiliary mass spatial probing using spectral centre correction method (SCCM), to provide a simple solution for damage detection by just using the response time history of beam-like structures. The natural frequencies of a damaged beam with a traversing auxiliary mass change due to change in the inertia of the beam as the auxiliary mass is traversed along the beam, as well as the point-to-point variations in the flexibility of the beam. Therefore the auxiliary mass can enhance the effects of the crack on the dynamics of the beam and, therefore, facilitate the identification and location of damage in the beam. That is, the auxiliary mass can be used to probe the dynamic characteristic of the beam by traversing the mass from one end of the beam to the other. However, it is impossible to obtain accurate modal frequencies by the direct operation of the fast Fourier transform (FFT) of the response data of the structure because the frequency spectrum can be only calculated from limited sampled time data which results in the well-known leakage effect. SCCM is identical to the energy centrobaric correction method (ECCM) which is a practical and effective method used in rotating mechanical fault diagnosis and which resolves the shortcoming of FFT and can provide high accuracy estimate of frequency, amplitude and phase. In the present work, the modal responses of damaged simply supported beams with auxiliary mass are computed using the finite element method (FEM). The graphical plots of the natural frequencies calculated by SCCM versus axial location of auxiliary mass are obtained. However, it is difficult to locate the crack directly from the curve of natural frequencies. A simple and fast method, the derivatives of natural frequency curve, is proposed in the paper which can provide crack information for damage detection of beam-like structures. The efficiency and practicability of the proposed method is illustrated via numerical

  16. Anti-interleukin-1 alpha autoantibodies in humans: Characterization, isotype distribution, and receptor-binding inhibition--higher frequency in Schnitzler's syndrome (urticaria and macroglobulinemia)

    International Nuclear Information System (INIS)

    Saurat, J.H.; Schifferli, J.; Steiger, G.; Dayer, J.M.; Didierjean, L.

    1991-01-01

    Since autoantibodies (Abs) to cytokines may modify their biologic activities, high-affinity binding factors for interleukin-1 alpha (IL-1 alpha BF) were characterized in human sera. IL-1 alpha BF was identified as IgG (1) by sucrose density-gradient centrifugation followed by immunodiffusion autoradiography, (2) by ligand-blotting method, (3) by ligand binding to affinity-immobilized serum IgG, and (4) by IgG affinity purification followed by sucrose density-gradient centrifugation. IL-1 alpha binding activity resided in the F(ab)2 fragment. The apparent equilibrium constant was in the range of IgG found after immunization with conventional antigens (i.e., 10(-9) to 10(-10) mol/L). Anti-IL-1 alpha IgG auto-Abs represented only an extremely small fraction of total IgG (less than 1/10(-5)). Some sera with IL-1 alpha BF and purified IgG thereof were able to inhibit by 96% to 98% the binding of human recombinant IL-1 alpha to its receptor on murine thymoma EL4-6.1 cells, whereas other sera did not. When 125I-labeled anti-IL-1 alpha IgG complexes were injected into rats, they prolonged the plasma half-life of 125I-labeled IL-1 alpha several fold and altered its tissue distribution. The predominant class was IgG (12/19), mainly IgG4 (9/19), but in five of the sera, anti-IL-1 alpha IgA was also detected. In a screening of 271 sera, IL-1 alpha BF was detected in 17/98 normal subjects and was not more frequent in several control groups of patients, except in patients with Schnitzler's syndrome (fever, chronic urticaria, bone pain, and monoclonal IgM paraprotein) (6/9; p less than 0.005). The pathologic significance of these auto-Abs remains to be determined

  17. Higher frequency of cagA EPIYA-C Phosphorylation Sites in H. pylori strains from first-degree relatives of gastric cancer patients

    Directory of Open Access Journals (Sweden)

    Queiroz Dulciene MM

    2012-08-01

    Full Text Available Abstract Background To evaluate the prevalence of more virulent H. pylori genotypes in relatives of gastric cancer patients and in patients without family histories of gastric cancer. Methods We evaluated prospectively the prevalence of the infection by more virulent H. pylori strains in 60 relatives of gastric cancer patients comparing the results with those obtained from 49 patients without family histories of gastric cancer. H. pylori status was determined by the urease test, histology and presence of H. pylori ureA. The cytotoxin associated gene (cagA, the cagA-EPIYA and vacuolating cytotoxin gene (vacA were typed by PCR and the cagA EPIYA typing was confirmed by sequencing. Results The gastric cancer relatives were significant and independently more frequently colonized by H. pylori strains with higher numbers of CagA-EPIYA-C segments (OR = 4.23, 95%CI = 1.53–11.69 and with the most virulent s1m1 vacA genotype (OR = 2.80, 95%CI = 1.04–7.51. Higher numbers of EPIYA-C segments were associated with increased gastric corpus inflammation, foveolar hyperplasia and atrophy. Infection by s1m1 vacA genotype was associated with increased antral and corpus gastritis. Conclusions We demonstrated that relatives of gastric cancer patients are more frequently colonized by the most virulent H. pylori cagA and vacA genotypes, which may contribute to increase the risk of gastric cancer.

  18. An improved sensor for precision detection of in situ stem water content using a frequency domain fringing capacitor.

    Science.gov (United States)

    Zhou, Haiyang; Sun, Yurui; Tyree, Melvin T; Sheng, Wenyi; Cheng, Qiang; Xue, Xuzhang; Schumann, Henrik; Schulze Lammers, Peter

    2015-04-01

    One role of stems is that of water storage. The water content of stems increases and decreases as xylem water potential increases and decreases, respectively. Hence, a nondestructive method to measure stem water content (StWC) = (volume of water) : (volume of stem), could be useful in monitoring the drought stress status of plants. We introduce a frequency domain inner fringing capacitor-sensor for measuring StWC which operates at 100 MHz frequency. The capacitor-sensor consists of two wave guides (5-mm-wide braided metal) that snugly fit around the surface of a stem with a spacing of 4-5 mm between guides. Laboratory measurements on analog stems reveals that the DC signal output responds linearly to the relative dielectric constant of the analog stem, is most sensitive to water content between the waveguides to a depth of c. 3 mm from the stem surface, and calibrations based on the gravimetric water loss of excised stems of plants revealed a resolution in StWC of < ± 0.001 v/ v. The sensor performed very well on whole plants with a 100-fold increased resolution compared with previous frequency domain and time domain reflectometry methods and, hence, may be very useful for future research requiring nondestructive measurements of whole plants. © European Union 2014. New Phytologist © 2014 New Phytologist Trust.

  19. Real-Time 12-Lead High-Frequency QRS Electrocardiography for Enhanced Detection of Myocardial Ischemia and Coronary Artery Disease

    Science.gov (United States)

    Schlegel, Todd T.; Kulecz, Walter B.; DePalma, Jude L.; Feiveson, Alan H.; Wilson, John S.; Rahman, M. Atiar; Bungo, Michael W.

    2004-01-01

    Several studies have shown that diminution of the high-frequency (HF; 150-250 Hz) components present within the central portion of the QRS complex of an electrocardiogram (ECG) is a more sensitive indicator for the presence of myocardial ischemia than are changes in the ST segments of the conventional low-frequency ECG. However, until now, no device has been capable of displaying, in real time on a beat-to-beat basis, changes in these HF QRS ECG components in a continuously monitored patient. Although several software programs have been designed to acquire the HF components over the entire QRS interval, such programs have involved laborious off-line calculations and postprocessing, limiting their clinical utility. We describe a personal computer-based ECG software program developed recently at the National Aeronautics and Space Administration (NASA) that acquires, analyzes, and displays HF QRS components in each of the 12 conventional ECG leads in real time. The system also updates these signals and their related derived parameters in real time on a beat-to-beat basis for any chosen monitoring period and simultaneously displays the diagnostic information from the conventional (low-frequency) 12-lead ECG. The real-time NASA HF QRS ECG software is being evaluated currently in multiple clinical settings in North America. We describe its potential usefulness in the diagnosis of myocardial ischemia and coronary artery disease.

  20. Design, Fabrication and Characterization of MIM Diodes and Frequency Selective Thermal Emitters for Solar Energy Harvesting and Detection Devices

    Science.gov (United States)

    Sharma, Saumya

    Energy harvesting using rectennas for infrared radiation continues to be a challenge due to the lack of fast switching diodes capable of rectification at THz frequencies. Metal insulator metal diodes which may be used at 30 THz must show adequate nonlinearity for small signal rectification such as 30 mV. In a rectenna assembly, the voltage signal received as an output from a single nanoantenna can be as small as ~30microV. Thus, only a hybrid array of nanoantennas can be sufficient to provide a signal in the ~30mV range for the diode to be able to rectify around 30THz. A metal-insulator-metal diode with highly nonlinear I-V characteristics is required in order for such small signal rectification to be possible. Such diode fabrication was found to be faced with two major fabrication challenges. The first one being the lack of a precisely controlled deposition process to allow a pinhole free insulator deposition less than 3nm in thickness. Another major challenge is the deposition of a top metal contact on the underlying insulating thin film. As a part of this research study, most of the MIM diodes were fabricated using Langmuir Blodgett monolayers deposited on a thin Ni film that was sputter coated on a silicon wafer. UV induced polymerization of the Langmuir Blodgett thin film was used to allow intermolecular crosslinking. A metal top contact was sputtered onto the underlying Langmuir Blodgett film assembly. In addition to material characterization of all the individual films using IR, UV-VIS spectroscopy, electron microscopy and atomic force microscopy, the I-V characteristics, resistance, current density, rectification ratio and responsivity with respect to the bias voltage were also measured for the electrical characterization of these MIM diodes. Further improvement in the diode rectification ratio and responsivity was obtained with Langmuir Blodgett films grown by the use of horizontally oriented organic molecules, due to a smaller tunneling distance that

  1. High Frequency Voltage Injection Methods and Observer Design for Initial Position Detection of Permanent Magnet Synchronous Machines

    DEFF Research Database (Denmark)

    Jin, Xinhai; Ni, Ronggang; Chen, Wei

    2018-01-01

    The information of the initial rotor position is essential for smooth start up and robust control of Permanent Magnet Synchronous Machines (PMSMs). RoTating Voltage Injection (RTVI) methods in the stationary reference frame have been commonly adopted to detect the initial rotor position at stands......The information of the initial rotor position is essential for smooth start up and robust control of Permanent Magnet Synchronous Machines (PMSMs). RoTating Voltage Injection (RTVI) methods in the stationary reference frame have been commonly adopted to detect the initial rotor position...

  2. Determining Energies and Cross Sections of Individual Ions Using Higher-Order Harmonics in Fourier Transform Charge Detection Mass Spectrometry (FT-CDMS).

    Science.gov (United States)

    Harper, Conner C; Elliott, Andrew G; Lin, Haw-Wei; Williams, Evan R

    2018-06-02

    A general method for in situ measurements of the energy of individual ions trapped and weighed using charge detection mass spectrometry (CDMS) is described. Highly charged (> 300 e), individual polyethylene glycol (PEG) ions are trapped and oscillate within an electrostatic trap, producing a time domain signal. A segmented Fourier transform (FT) of this signal yields the temporal evolution of the fundamental and harmonic frequencies of ion motion throughout the 500-ms trap time. The ratio of the fundamental frequency and second harmonic (HAR) depends on the ion energy, which is an essential parameter for measuring ion mass in CDMS. This relationship is calibrated using simulated ion signals, and the calibration is compared to the HAR values measured for PEG ion signals where the ion energy was also determined using an independent method that requires that the ions be highly charged (> 300 e). The mean error of 0.6% between the two measurements indicates that the HAR method is an accurate means of ion energy determination that does not depend on ion size or charge. The HAR is determined dynamically over the entire trapping period, making it possible to observe the change in ion energy that takes place as solvent evaporates from the ion and collisions with background gas occur. This method makes it possible to measure mass changes, either from solvent evaporation or from molecular fragmentation (MS n ), as well as the cross sections of ions measured using CDMS. Graphical Abstract.

  3. Real-time monitoring for detection of retained surgical sponges and team motion in the surgical operation room using radio-frequency-identification (RFID) technology: a preclinical evaluation.

    Science.gov (United States)

    Kranzfelder, Michael; Zywitza, Dorit; Jell, Thomas; Schneider, Armin; Gillen, Sonja; Friess, Helmut; Feussner, Hubertus

    2012-06-15

    Technical progress in the surgical operating room (OR) increases constantly, facilitating the development of intelligent OR systems functioning as "safety backup" in the background of surgery. Precondition is comprehensive data retrieval to identify imminent risky situations and inaugurate adequate security mechanisms. Radio-frequency-identification (RFID) technology may have the potential to meet these demands. We set up a pilot study investigating feasibility and appliance reliability of a stationary RFID system for real-time surgical sponge monitoring (passive tagged sponges, position monitoring: mayo-stand/abdominal situs/waste bucket) and OR team tracking (active transponders, position monitoring: right/left side of OR table). In vitro: 20/20 sponges (100%) were detected on the mayo-stand and within the OR-phantom, however, real-time detection accuracy declined to 7/20 (33%) when the tags were moved simultaneously. All retained sponges were detected correctly. In vivo (animal): 7-10/10 sterilized sponges (70%-100%) were detected correctly within the abdominal cavity. OR-team: detection accuracy within the OR (surveillance antenna) and on both sides of the OR table (sector antenna) was 100%. Mean detection time for position change (left to right side and contrariwise) was 30-60 s. No transponder failure was noted. This is the first combined RFID system that has been developed for stationary use in the surgical OR. Preclinical evaluation revealed a reliable sponge tracking and correct detection of retained textiles (passive RFID) but also demonstrated feasibility of comprehensive data acquisition of team motion (active RFID). However, detection accuracy needs to be further improved before implementation into the surgical OR. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. The Use of Low-frequency Active Channel Signals in an Information Leakage Detection and Prevention Systems

    Directory of Open Access Journals (Sweden)

    A. V. Mamaev

    2011-06-01

    Full Text Available This article describes a solution for the protection of the temporary lifting of control over the target machine, while using information leakage detection and prevention systems. It is proposed to use a specially designed channel for alert’s signals through the computer’s power supply.

  5. The Hardware and Software Implementation of Low-Frequency Active Channel Signals in an Information Leakage Detection and Prevention Systems

    Directory of Open Access Journals (Sweden)

    A. V. Mamaev

    2011-12-01

    Full Text Available This article discusses a new way of developing a special channel for the alarms, through computer’s power supply network, to solve the problem of protection from removal of the temporary control over the victim’s machine, using information leakage detection and prevention systems.

  6. The JET Alfven Eigenmode Local Manager for the real-time detection and tracking of a frequency-degenerate spectrum of MHD instabilities

    International Nuclear Information System (INIS)

    Testa, D.; Carfantan, H.; Fasoli, A.; Goodyear, A.; King, Q.; Blanchard, P.; Klein, A.; Lavanchy, P.; Panis, T.

    2011-01-01

    We present the real-time VME system used to detect and track MHD instabilities, and particularly Alfven Eigenmodes, on the JET tokamak [J. Wesson, Tokamaks, 3rd ed., Oxford Science Publication, Oxford, 2003, p. 617]. This system runs on a 1 kHz clock cycle, and allows performing a real-time, unsupervised and blind detection, decomposition and tracking of the individual components in a frequency-degenerate, multi-harmonic spectrum, using a small number of input data which are unevenly sampled in the spatial domain. This makes it possible to follow in real-time the detected modes as the plasma background evolves, and measure in real-time their frequency, damping rate, toroidal mode-number and relative amplitude. The successful implementation of this system opens a clear path towards developing real-time control tools for electro-magnetic instabilities in future fusion devices aimed at achieving a net energy gain, such as ITER [J. Wesson, Tokamaks, 3rd ed., Oxford Science Publication, Oxford, 2003, p. 711].

  7. Superconducting electron tunneling as detection method for low frequency resonant vibration modes of interstitials in fcc lead

    International Nuclear Information System (INIS)

    Adrian, H.

    1981-01-01

    The influence of crystal defects on the phonon spectra was studied for fcc lead using superconducting tunneling spectroscopy. The theory predicts low frequency modes for the vibrational states of interstitials in (100) dumbbell configuration. Low temperature irradiation of superconducting point contacts with fast ions (point contact thickness small compared to the average ion range) showed radiation-induced structures in the low-energy part of the Eliashberg function for lead. These resonant modes are reduced by annealing at 18.5 K; they are attributed to small interstitial clusters. The radiation-induced structures are completely removed by room temperature annealing. (orig.)

  8. Micromachined silicon cantilevers with integrated high-frequency magnetoimpedance sensors for simultaneous strain and magnetic field detection

    Science.gov (United States)

    Buettel, G.; Joppich, J.; Hartmann, U.

    2017-12-01

    Giant magnetoimpedance (GMI) measurements in the high-frequency regime utilizing a coplanar waveguide with an integrated Permalloy multilayer and micromachined on a silicon cantilever are reported. The fabrication process is described in detail. The aspect ratio of the magnetic multilayer in the magnetoresistive and magnetostrictive device was varied. Tensile strain and compressive strain were applied. Vector network analyzer measurements in the range from the skin effect to ferromagnetic resonance confirm the technological potential of GMI-based micro-electro-mechanical devices for strain and magnetic field sensing applications. The strain-impedance gauge factor was quantified by finite element strain calculations and reaches a maximum value of almost 200.

  9. Detection of Very Low-Frequency Quasi-Periodic Oscillations in the 2015 Outburst of V404 Cygni

    DEFF Research Database (Denmark)

    Huppenkothen, D.; Younes, G.; Ingram, A.

    2016-01-01

    -ray missions: Swift/XRT, Fermi/GBM, Chandra/ACIS, INTEGRAL's IBIS/ISGRI and JEM-X, and NuSTAR. We report the detection of a QPO at 18 mHz simultaneously with both Fermi/GBM and Swift/XRT, another example of a rare but slowly growing new class of mHz-QPOs in BHXRBs linked to sources with a high orbital...

  10. Frequencies of X-ray and fast neutron induced chromosome translocations in human peripheral blood lymphocytes as detected by in situ hybridization using chromosome specific DNA libraries

    International Nuclear Information System (INIS)

    Natarajan, A.T.; Darroudi, F.; Vermeulen, S.; Wiegant, J.

    1992-01-01

    DNA libraries of six human chromosomes were used to detect translocations in human lymphocytes induced by different doses of X-rays and fast neutrons. Results show that with X-rays, one can detect about 1.5 to 2.0 fold more translocations in comparison to dicentrics, whereas following fast neutron irradiation, the difference between these two classes of aberrations are significantly different at high doses. In addition, triple fluorescent in situ hybridization technique was used to study the frequencies of radiation-induced translocations involving a specific chromosome. Chromosome number 1 was found to be involved in translocations more frequently than chromosomes number 2, 3, 4, 8 and X. (author). 10 refs., 1 fig., 2 tabs

  11. Very low frequency earthquakes (VLFEs) detected during episodic tremor and slip (ETS) events in Cascadia using a match filter method indicate repeating events

    Science.gov (United States)

    Hutchison, A. A.; Ghosh, A.

    2016-12-01

    Very low frequency earthquakes (VLFEs) occur in transitional zones of faults, releasing seismic energy in the 0.02-0.05 Hz frequency band over a 90 s duration and typically have magntitudes within the range of Mw 3.0-4.0. VLFEs can occur down-dip of the seismogenic zone, where they can transfer stress up-dip potentially bringing the locked zone closer to a critical failure stress. VLFEs also occur up-dip of the seismogenic zone in a region along the plate interface that can rupture coseismically during large megathrust events, such as the 2011 Tohoku-Oki earthquake [Ide et al., 2011]. VLFEs were first detected in Cascadia during the 2011 episodic tremor and slip (ETS) event, occurring coincidentally with tremor [Ghosh et al., 2015]. However, during the 2014 ETS event, VLFEs were spatially and temporally asynchronous with tremor activity [Hutchison and Ghosh, 2016]. Such contrasting behaviors remind us that the mechanics behind such events remain elusive, yet they are responsible for the largest portion of the moment release during an ETS event. Here, we apply a match filter method using known VLFEs as template events to detect additional VLFEs. Using a grid-search centroid moment tensor inversion method, we invert stacks of the resulting match filter detections to ensure moment tensor solutions are similar to that of the respective template events. Our ability to successfully employ a match filter method to VLFE detection in Cascadia intrinsically indicates that these events can be repeating, implying that the same asperities are likely responsible for generating multiple VLFEs.

  12. Novel Quantitative Real-Time LCR for the Sensitive Detection of SNP Frequencies in Pooled DNA: Method Development, Evaluation and Application

    Science.gov (United States)

    Psifidi, Androniki; Dovas, Chrysostomos; Banos, Georgios

    2011-01-01

    Background Single nucleotide polymorphisms (SNP) have proven to be powerful genetic markers for genetic applications in medicine, life science and agriculture. A variety of methods exist for SNP detection but few can quantify SNP frequencies when the mutated DNA molecules correspond to a small fraction of the wild-type DNA. Furthermore, there is no generally accepted gold standard for SNP quantification, and, in general, currently applied methods give inconsistent results in selected cohorts. In the present study we sought to develop a novel method for accurate detection and quantification of SNP in DNA pooled samples. Methods The development and evaluation of a novel Ligase Chain Reaction (LCR) protocol that uses a DNA-specific fluorescent dye to allow quantitative real-time analysis is described. Different reaction components and thermocycling parameters affecting the efficiency and specificity of LCR were examined. Several protocols, including gap-LCR modifications, were evaluated using plasmid standard and genomic DNA pools. A protocol of choice was identified and applied for the quantification of a polymorphism at codon 136 of the ovine PRNP gene that is associated with susceptibility to a transmissible spongiform encephalopathy in sheep. Conclusions The real-time LCR protocol developed in the present study showed high sensitivity, accuracy, reproducibility and a wide dynamic range of SNP quantification in different DNA pools. The limits of detection and quantification of SNP frequencies were 0.085% and 0.35%, respectively. Significance The proposed real-time LCR protocol is applicable when sensitive detection and accurate quantification of low copy number mutations in DNA pools is needed. Examples include oncogenes and tumour suppressor genes, infectious diseases, pathogenic bacteria, fungal species, viral mutants, drug resistance resulting from point mutations, and genetically modified organisms in food. PMID:21283808

  13. Raft and floating radio frequency identification (RFID) antenna systems for detecting and estimating abundance of PIT-tagged fish in rivers

    Science.gov (United States)

    Fetherman, Eric R.; Avila, Brian W.; Winkelman, Dana L.

    2016-01-01

    Portable radio frequency identification (RFID) PIT tag antenna systems are increasingly being used in studies examining aquatic animal movement, survival, and habitat use, and their design flexibility permits application in a wide variety of settings. We describe the construction, use, and performance of two portable floating RFID PIT tag antenna systems designed to detect fish that were unavailable for recapture using stationary antennas or electrofishing. A raft antenna system was designed to detect and locate PIT-tagged fish in relatively long (i.e., ≥10 km) river reaches, and consisted of two antennas: (1) a horizontal antenna (4 × 1.2 m) installed on the bottom of the raft and used to detect fish in shallower river reaches (<1 m), and (2) a vertical antenna (2.7 × 1.2 m) for detecting fish in deeper pools (≥1 m). Detection distances of the horizontal antenna were between 0.7 and 1.0 m, and detection probability was 0.32 ± 0.02 (mean ± SE) in a field test using rocks marked with 32-mm PIT tags. Detection probability of PIT-tagged fish in the Cache la Poudre River, Colorado, using the raft antenna system, which covered 21% of the wetted area, was 0.14 ± 0.14. A shore-deployed floating antenna (14.6 × 0.6 m), which covered 100% of the wetted area, was designed for use by two operators for detecting and locating PIT-tagged fish in shorter (i.e., <2 km) river reaches. Detection distances of the shore-deployed floating antenna were between 0.7 and 0.8 m, and detection probabilities during field deployment in the St. Vrain River exceeded 0.52. The shore-deployed floating antenna was also used to estimate abundance of PIT-tagged fish. Results suggest that the shore-deployed floating antenna could be used as an alternative to estimating abundance using traditional sampling methods such as electrofishing.

  14. Sensitivity and Frequencies of Dystrophin Gene Mutations in Thai DMD/BMD Patients As Detected by Multiplex PCR

    Directory of Open Access Journals (Sweden)

    Thanyachai Sura

    2008-01-01

    Full Text Available Background: Duchenne muscular dystrophy (DMD, a lethal X-linked disease affecting 1 in 3500 male births, and its more benign variant, Becker muscular dystrophy (BMD, are caused by mutations in the dystrophin gene. Because of its large size, analysing the whole gene is impractical. Methods have been developed to detect the commonest mutations i.e. the deletions of the exons. Although these tests are highly specific, their sensitivity is inherently limited by the prevalence of deletions, which differs among different populations.

  15. The Montreal Cognitive Assessment is superior to the Mini-Mental State Examination in detecting patients at higher risk of dementia.

    Science.gov (United States)

    Dong, YanHong; Lee, Wah Yean; Basri, Nur Adilah; Collinson, Simon Lowes; Merchant, Reshma A; Venketasubramanian, Narayanaswamy; Chen, Christopher Li-Hsian

    2012-11-01

    To examine the discriminant validity of the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE) in detecting patients with cognitive impairment at higher risk for dementia at a memory clinic setting. Memory clinic patients were administered the MoCA, MMSE, and a comprehensive formal neuropsychological battery. Mild cognitive impairment (MCI) subtypes were dichotomized into two groups: single domain-MCI (sd-MCI) and multiple domain-MCI (md-MCI). Area under the receiver operating characteristic curve (ROC) analysis was used to compare the discriminatory ability of the MoCA and the MMSE. Two hundred thirty patients were recruited, of which 136 (59.1%) were diagnosed with dementia, 61 (26.5%) with MCI, and 33 (14.3%) with no cognitive impairment (NCI). The majority of MCI patients had md-MCI (n = 36, 59%). The MoCA had significantly larger AUCs than the MMSE in discriminating md-MCI from the lower risk group for incident dementia (NCI and sd-MCI) [MoCA 0.92 (95% CI, 0.86-0.98) vs. MMSE 0.84 (95% CI, 0.75-0.92), p = 0.02). At their optimal cut-off points, the MoCA (19/20) remained superior to the MMSE (23/24) in detecting md-MCI [sensitivity: 0.83 vs. 0.72; specificity: 0.86 vs. 0.83; PPV: 0.79 vs. 0.72; NPV: 0.89 vs. 0.83; correctly classified: 85.1% vs. 78.7%]. The MoCA is superior to the MMSE in the detection of patients with cognitive impairment at higher risk for incident dementia at a memory clinic setting.

  16. Detection of increased frequency of thyroid hypoplasia in subjects irradiated in utero as the results of Chernobyl catastrophe

    Energy Technology Data Exchange (ETDEWEB)

    Drozd, V.; Danilova, L.; Lushchyk, M.; Leonova, T.; Platonova, T. [International Fund Arnica, Minsk (Belarus); Grigorovich, A.; Sivuda, V. [Brest Regional Endocrinological Dispensary, Brest (Belarus); Branovan, I. [Chernobyl Project, New-York (United States); Biko, I.; Reiners, C. [Clinic and Policlinic of Nuclear Medicine, University of Wurzburg, Wursburg (Germany)

    2012-07-01

    For the 24 years passed after the Chernobyl catastrophe a significant experience in estimation of medical consequences of thyroid irradiation among Belarus patients had been accumulated. The aim of our screening of ultrasonic examination was the detection of the thyroid hypoplasia prevalence in the regions affected with radionuclide fallout. Since 2004 to 2007 thyroid ultrasound with volume estimation was performed in 3311 Belarus subjects, living on the areas of Brest region with the different contamination rate density. Examined subjects were divided in 3 groups: 1) irradiated at the age of 1 to 3 years old at the moment of Chernobyl catastrophe, 2) irradiated in utero, and 3) born after the catastrophe. It was revealed that thyroid hypoplasia was detected in 3% of group 1 (out of 1876 persons), in 5, 8% of group 2 (out of 503 persons, P<0.05) and in 1, 7% of the third group (out of 932 persons). The separation of the irradiated in utero subjects (group 2) to subgroups in dependence of the gestation period, showed the highest prevalence of thyroid hypoplasia among the irradiated in the first trimester of gestation: 7, 7% (P<0.05), in the second trimester: 5, 3%, in the third trimester: 4, 7%

  17. Detection of increased frequency of thyroid hypoplasia in subjects irradiated in utero as the results of Chernobyl catastrophe

    International Nuclear Information System (INIS)

    Drozd, V.; Danilova, L.; Lushchyk, M.; Leonova, T.; Platonova, T.; Grigorovich, A.; Sivuda, V.; Branovan, I.; Biko, I.; Reiners, C.

    2012-01-01

    For the 24 years passed after the Chernobyl catastrophe a significant experience in estimation of medical consequences of thyroid irradiation among Belarus patients had been accumulated. The aim of our screening of ultrasonic examination was the detection of the thyroid hypoplasia prevalence in the regions affected with radionuclide fallout. Since 2004 to 2007 thyroid ultrasound with volume estimation was performed in 3311 Belarus subjects, living on the areas of Brest region with the different contamination rate density. Examined subjects were divided in 3 groups: 1) irradiated at the age of 1 to 3 years old at the moment of Chernobyl catastrophe, 2) irradiated in utero, and 3) born after the catastrophe. It was revealed that thyroid hypoplasia was detected in 3% of group 1 (out of 1876 persons), in 5, 8% of group 2 (out of 503 persons, P<0.05) and in 1, 7% of the third group (out of 932 persons). The separation of the irradiated in utero subjects (group 2) to subgroups in dependence of the gestation period, showed the highest prevalence of thyroid hypoplasia among the irradiated in the first trimester of gestation: 7, 7% (P<0.05), in the second trimester: 5, 3%, in the third trimester: 4, 7%

  18. DETECTION OF VERY LOW-FREQUENCY, QUASI-PERIODIC OSCILLATIONS IN THE 2015 OUTBURST OF V404 CYGNI

    Energy Technology Data Exchange (ETDEWEB)

    Huppenkothen, D. [Center for Data Science, New York University, 726 Broadway, 7th Floor, New York, NY 10003 (United States); Younes, G.; Kouveliotou, C. [Department of Physics, The George Washington University, Washington, DC 20052 (United States); Ingram, A.; Van der Klis, M. [Anton Pannekoek Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Göğüş, E. [Sabancı University, Orhanlı-Tuzla, İstanbul 34956 (Turkey); Bachetti, M. [INAF/Osservatorio Astronomico di Cagliari, via della Scienza 5, I-09047 Selargius (Italy); Sánchez-Fernández, C.; Kuulkers, E. [European Space Astronomy Centre (ESA/ESAC), Science Operations Department, E-28691 Villanueva de la Cañada, Madrid (Spain); Chenevez, J. [DTU Space—National Space Institute, Technical University of Denmark, Elektrovej 327-328, DK-2800 Lyngby (Denmark); Motta, S. [University of Oxford, Department of Physics, Astrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Raanana 43537 (Israel); Gehrels, N. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Tomsick, J. A. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Walton, D. J., E-mail: daniela.huppenkothen@nyu.edu [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)

    2017-01-01

    In 2015 June, the black hole X-ray binary (BHXRB) V404 Cygni went into outburst for the first time since 1989. Here, we present a comprehensive search for quasi-periodic oscillations (QPOs) of V404 Cygni during its recent outburst, utilizing data from six instruments on board five different X-ray missions: Swift /XRT, Fermi /GBM, Chandra /ACIS, INTEGRAL ’s IBIS/ISGRI and JEM-X, and NuSTAR . We report the detection of a QPO at 18 mHz simultaneously with both Fermi /GBM and Swift /XRT, another example of a rare but slowly growing new class of mHz-QPOs in BHXRBs linked to sources with a high orbital inclination. Additionally, we find a duo of QPOs in a Chandra /ACIS observation at 73 mHz and 1.03 Hz, as well as a QPO at 136 mHz in a single Swift /XRT observation that can be interpreted as standard Type-C QPOs. Aside from the detected QPOs, there is significant structure in the broadband power, with a strong feature observable in the Chandra observations between 0.1 and 1 Hz. We discuss our results in the context of current models for QPO formation.

  19. Frequency and Detection of Malingering in Homicide Defendants Undergoing Criminal Responsibility Evaluations Using the Schedule for Nonadaptive and Adaptive Personality

    Directory of Open Access Journals (Sweden)

    Wade C. Myers

    2016-04-01

    Full Text Available This retrospective study reports on (a the prevalence of malingering in a sample of 20 homicide defendants seen in jail settings for criminal responsibility evaluations, and (b the feasibility of the Schedule for Nonadaptive and Adaptive Personality (SNAP for malingering detection in this sample. Based on previous non-clinical simulation research, it was hypothesized that the SNAP validity scales would predict group membership for homicide defendants malingering psychopathology. Those with intellectual disabilities or psychotic disorders were excluded. Diagnostically, nearly one half of the sample had Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR personality and substance use disorders. Point prevalence of malingering was 30%. Using the criterion of any SNAP validity scale score in the clinical range (T ≥ 65, a reasonable sensitivity was demonstrated in the detection of malingering (83%, yet this outcome was hindered by a high false positive rate (64%. This study suggests further exploration of the SNAP for assessing malingering in forensic populations is warranted.

  20. An Asymmetry in the Automatic Detection of the Presence or Absence of a Frequency Modulation within a Tone: A Mismatch Negativity Study

    Science.gov (United States)

    Timm, Jana; Weise, Annekathrin; Grimm, Sabine; Schröger, Erich

    2011-01-01

    The infrequent occurrence of a transient feature (deviance; e.g., frequency modulation, FM) in one of the regular occurring sinusoidal tones (standards) elicits the deviance related mismatch negativity (MMN) component of the event-related brain potential. Based on a memory-based comparison, MMN reflects the mismatch between the representations of incoming and standard sounds. The present study investigated to what extent the infrequent exclusion of an FM is detected by the MMN system. For that purpose we measured MMN to deviances that either consisted of the exclusion or inclusion of an FM at an early or late position within the sound that was present or absent, respectively, in the standard. According to the information-content hypothesis, deviance detection relies on the difference in informational content of the deviant relative to that of the standard. As this difference between deviants with FM and standards without FM is the same as in the reversed case, comparable MMNs should be elicited to FM inclusions and exclusions. According to the feature-detector hypothesis, however, the deviance detection depends on the increased activation of feature detectors to additional sound features. Thus, rare exclusions of the FM should elicit no or smaller MMN than FM inclusions. In passive listening condition, MMN was obtained only for the early inclusion, but not for the exclusions nor for the late inclusion of an FM. This asymmetry in automatic deviance detection seems to partly reflect the contribution of feature detectors even though it cannot fully account for the missing MMN to late FM inclusions. Importantly, the behavioral deviance detection performance in the active listening condition did not reveal such an asymmetry, suggesting that the intentional detection of the deviants is based on the difference in informational content. On a more general level, the results partly support the “fresh-afferent” account or an extended memory-comparison based account of MMN

  1. Raft and floating radio frequency identification (RFID) antenna systems for detecting and estimating abundance of PIT-tagged fish in rivers

    Science.gov (United States)

    Fetherman, Eric R.; Avila, Brian W.; Winkelman, Dana L.

    2016-01-01

    Portable radio frequency identification (RFID) PIT tag antenna systems are increasingly being used in studies examining aquatic animal movement, survival, and habitat use, and their design flexibility permits application in a wide variety of settings. We describe the construction, use, and performance of two portable floating RFID PIT tag antenna systems designed to detect fish that were unavailable for recapture using stationary antennas or electrofishing. A raft antenna system was designed to detect and locate PIT-tagged fish in relatively long (i.e., ≥10 km) river reaches, and consisted of two antennas: (1) a horizontal antenna (4 × 1.2 m) installed on the bottom of the raft and used to detect fish in shallower river reaches (raft antenna system, which covered 21% of the wetted area, was 0.14 ± 0.14. A shore-deployed floating antenna (14.6 × 0.6 m), which covered 100% of the wetted area, was designed for use by two operators for detecting and locating PIT-tagged fish in shorter (i.e., <2 km) river reaches. Detection distances of the shore-deployed floating antenna were between 0.7 and 0.8 m, and detection probabilities during field deployment in the St. Vrain River exceeded 0.52. The shore-deployed floating antenna was also used to estimate abundance of PIT-tagged fish. Results suggest that the shore-deployed floating antenna could be used as an alternative to estimating abundance using traditional sampling methods such as electrofishing.

  2. Data-driven approach to detect common copy-number variations and frequency profiles in a population-based Korean cohort.

    Science.gov (United States)

    Moon, Sanghoon; Kim, Young Jin; Hong, Chang Bum; Kim, Dong-Joon; Lee, Jong-Young; Kim, Bong-Jo

    2011-11-01

    To date, hundreds of thousands of copy-number variation (CNV) data have been reported using various platforms. The proportion of Asians in these data is, however, relatively small as compared with that of other ethnic groups, such as Caucasians and Yorubas. Because of limitations in platform resolution and the high noise level in signal intensity, in most CNV studies (particularly those using single nucleotide polymorphism arrays), the average number of CNVs in an individual is less than the number of known CNVs. In this study, we ascertained reliable, common CNV regions (CNVRs) and identified actual frequency rates in the Korean population to provide more CNV information. We performed two-stage analyses for detecting structural variations with two platforms. We discovered 576 common CNVRs (88 CNV segments on average in an individual), and 87% (501 of 576) of these CNVRs overlapped by ≥1 bp with previously validated CNV events. Interestingly, from the frequency analysis of CNV profiles, 52 of 576 CNVRs had a frequency rate of population.

  3. Multi-Sensor Detection with Particle Swarm Optimization for Time-Frequency Coded Cooperative WSNs Based on MC-CDMA for Underground Coal Mines

    Directory of Open Access Journals (Sweden)

    Jingjing Xu

    2015-08-01

    Full Text Available In this paper, a wireless sensor network (WSN technology adapted to underground channel conditions is developed, which has important theoretical and practical value for safety monitoring in underground coal mines. According to the characteristics that the space, time and frequency resources of underground tunnel are open, it is proposed to constitute wireless sensor nodes based on multicarrier code division multiple access (MC-CDMA to make full use of these resources. To improve the wireless transmission performance of source sensor nodes, it is also proposed to utilize cooperative sensors with good channel conditions from the sink node to assist source sensors with poor channel conditions. Moreover, the total power of the source sensor and its cooperative sensors is allocated on the basis of their channel conditions to increase the energy efficiency of the WSN. To solve the problem that multiple access interference (MAI arises when multiple source sensors transmit monitoring information simultaneously, a kind of multi-sensor detection (MSD algorithm with particle swarm optimization (PSO, namely D-PSO, is proposed for the time-frequency coded cooperative MC-CDMA WSN. Simulation results show that the average bit error rate (BER performance of the proposed WSN in an underground coal mine is improved significantly by using wireless sensor nodes based on MC-CDMA, adopting time-frequency coded cooperative transmission and D-PSO algorithm with particle swarm optimization.

  4. Health State Monitoring of Bladed Machinery with Crack Growth Detection in BFG Power Plant Using an Active Frequency Shift Spectral Correction Method

    Directory of Open Access Journals (Sweden)

    Weifang Sun

    2017-08-01

    Full Text Available Power generation using waste-gas is an effective and green way to reduce the emission of the harmful blast furnace gas (BFG in pig-iron producing industry. Condition monitoring of mechanical structures in the BFG power plant is of vital importance to guarantee their safety and efficient operations. In this paper, we describe the detection of crack growth of bladed machinery in the BFG power plant via vibration measurement combined with an enhanced spectral correction technique. This technique enables high-precision identification of amplitude, frequency, and phase information (the harmonic information belonging to deterministic harmonic components within the vibration signals. Rather than deriving all harmonic information using neighboring spectral bins in the fast Fourier transform spectrum, this proposed active frequency shift spectral correction method makes use of some interpolated Fourier spectral bins and has a better noise-resisting capacity. We demonstrate that the identified harmonic information via the proposed method is of suppressed numerical error when the same level of noises is presented in the vibration signal, even in comparison with a Hanning-window-based correction method. With the proposed method, we investigated vibration signals collected from a centrifugal compressor. Spectral information of harmonic tones, related to the fundamental working frequency of the centrifugal compressor, is corrected. The extracted spectral information indicates the ongoing development of an impeller blade crack that occurred in the centrifugal compressor. This method proves to be a promising alternative to identify blade cracks at early stages.

  5. Multi-Sensor Detection with Particle Swarm Optimization for Time-Frequency Coded Cooperative WSNs Based on MC-CDMA for Underground Coal Mines.

    Science.gov (United States)

    Xu, Jingjing; Yang, Wei; Zhang, Linyuan; Han, Ruisong; Shao, Xiaotao

    2015-08-27

    In this paper, a wireless sensor network (WSN) technology adapted to underground channel conditions is developed, which has important theoretical and practical value for safety monitoring in underground coal mines. According to the characteristics that the space, time and frequency resources of underground tunnel are open, it is proposed to constitute wireless sensor nodes based on multicarrier code division multiple access (MC-CDMA) to make full use of these resources. To improve the wireless transmission performance of source sensor nodes, it is also proposed to utilize cooperative sensors with good channel conditions from the sink node to assist source sensors with poor channel conditions. Moreover, the total power of the source sensor and its cooperative sensors is allocated on the basis of their channel conditions to increase the energy efficiency of the WSN. To solve the problem that multiple access interference (MAI) arises when multiple source sensors transmit monitoring information simultaneously, a kind of multi-sensor detection (MSD) algorithm with particle swarm optimization (PSO), namely D-PSO, is proposed for the time-frequency coded cooperative MC-CDMA WSN. Simulation results show that the average bit error rate (BER) performance of the proposed WSN in an underground coal mine is improved significantly by using wireless sensor nodes based on MC-CDMA, adopting time-frequency coded cooperative transmission and D-PSO algorithm with particle swarm optimization.

  6. Health State Monitoring of Bladed Machinery with Crack Growth Detection in BFG Power Plant Using an Active Frequency Shift Spectral Correction Method.

    Science.gov (United States)

    Sun, Weifang; Yao, Bin; He, Yuchao; Chen, Binqiang; Zeng, Nianyin; He, Wangpeng

    2017-08-09

    Power generation using waste-gas is an effective and green way to reduce the emission of the harmful blast furnace gas (BFG) in pig-iron producing industry. Condition monitoring of mechanical structures in the BFG power plant is of vital importance to guarantee their safety and efficient operations. In this paper, we describe the detection of crack growth of bladed machinery in the BFG power plant via vibration measurement combined with an enhanced spectral correction technique. This technique enables high-precision identification of amplitude, frequency, and phase information (the harmonic information) belonging to deterministic harmonic components within the vibration signals. Rather than deriving all harmonic information using neighboring spectral bins in the fast Fourier transform spectrum, this proposed active frequency shift spectral correction method makes use of some interpolated Fourier spectral bins and has a better noise-resisting capacity. We demonstrate that the identified harmonic information via the proposed method is of suppressed numerical error when the same level of noises is presented in the vibration signal, even in comparison with a Hanning-window-based correction method. With the proposed method, we investigated vibration signals collected from a centrifugal compressor. Spectral information of harmonic tones, related to the fundamental working frequency of the centrifugal compressor, is corrected. The extracted spectral information indicates the ongoing development of an impeller blade crack that occurred in the centrifugal compressor. This method proves to be a promising alternative to identify blade cracks at early stages.

  7. Detecting new γ-ray sources based on multi-frequency data the case of 1WHSPJ031423.9+061956

    Science.gov (United States)

    Arsioli, Bruno; Chang, Yu Ling

    2015-12-01

    We use the Fermi Science Tools in an attempt to unveil faint γ-ray blazars that may be above the threshold for detectability with Fermi-LAT and are not identified by automated methods. Our search for new sources in the 100MeV-300GeV band is mainly driven by the 1/2WHSP catalogs, which list high synchrotron peaked blazars expected to be emitters of VHE photons. Here we present the γ-ray detection of 1WHSP J031423.9+061956, modelling its high energy spectrum as a power law. We describe an example where multi-frequency selection, performed at much lower energies (from radio to X-ray), helps to pin-point a high energy source. The 1/2WHSP catalogs are built with the aim of providing a list of TeV targets for the VHE arrays of Cherenkov telescopes. Moreover, these catalogs provide useful seeds for identifying new high energy sources within the raw-data from Fermi. With the aid of multi-frequency data, we can explore the very high energy domain in greater details, improving the description of the γ-ray sky.

  8. A novel approach using time-frequency analysis of pulse-oximeter data to detect progressive hypovolemia in spontaneously breathing healthy subjects.

    Science.gov (United States)

    Selvaraj, Nandakumar; Shelley, Kirk H; Silverman, David G; Stachenfeld, Nina; Galante, Nicholas; Florian, John P; Mendelson, Yitzhak; Chon, K

    2011-08-01

    Accurate and early detection of blood volume loss would greatly improve intraoperative and trauma care. This study has attempted to determine early diagnostic and quantitative markers for blood volume loss by analyzing photoplethysmogram (PPG) data from ear, finger and forehead sites with our high-resolution time-frequency spectral (TFS) technique in spontaneously breathing healthy subjects (n = 11) subjected to lower body negative pressure (LBNP). The instantaneous amplitude modulations present in heart rate (AM HR) and breathing rate (AMBR) band frequencies of PPG signals were calculated from the high-resolution TFS. Results suggested that the changes (P signals, respectively. The mean percent increase in AMBR values at 100% LBNP tolerance was 99.4% and 19.6% for ear and finger sites, respectively; AMBR values were not attainable for forehead PPG signal. Even without baseline AMHR values, our results suggest that hypovolemia detection is possible with specificity and sensitivity greater than 90% for the ear and forehead locations when LBNP tolerance is 100%. Therefore, the TFS analysis of noninvasive PPG waveforms is promising for early diagnosis and quantification of hypovolemia at levels not identified by vital signs in spontaneously breathing subjects.

  9. Aging phenomena of chitosan and chitosan-diclofenac sodium system detected by low-frequency dielectric spectroscopy.

    Science.gov (United States)

    Bodek, K H; Bak, G W

    1999-09-01

    The use of natural polymers for design of dosage form has received considerable attention recently, especially from the safety point of view. Among these polymers, chitosan shows very interesting biological, chemical and physical properties which makes it possible to use chitosan for various pharmaceutical applications. Microcrystalline chitosan (MCCh) is a special multifunctional polymeric material existing in the form of either of gelatinous water dispersion or a powder. Thermal aging of chitosan and chitosan-diclofenac sodium mixture have been studied using low-frequency dielectric measurements. The aging was carried out by annealing in ambient atmosphere in the temperature range between 25 degrees C and 100 degrees C. The dielectric losses in the aged samples proved to decrease by about one order of magnitude. The additional measurements of molecular weight distribution and infrared absorption were also carried out for better understanding of nature of the ageing phenomena. Partial evacuation of water, cross-linking and improvement of structural order may be suggested to be a result of thermal aging of the investigated materials.

  10. Optimal degree of protonation for {sup 1}H detection of aliphatic sites in randomly deuterated proteins as a function of the MAS frequency

    Energy Technology Data Exchange (ETDEWEB)

    Asami, Sam [Helmholtz-Zentrum Muenchen (HMGU), Deutsches Forschungszentrum fuer Gesundheit und Umwelt (HMGU) (Germany); Szekely, Kathrin; Schanda, Paul; Meier, Beat H. [Eidgenoessische Technische Hochschule Zuerich (ETH Zuerich) (Switzerland); Reif, Bernd, E-mail: reif@tum.de [Helmholtz-Zentrum Muenchen (HMGU), Deutsches Forschungszentrum fuer Gesundheit und Umwelt (HMGU) (Germany)

    2012-10-15

    The {sup 1}H dipolar network, which is the major obstacle for applying proton detection in the solid-state, can be reduced by deuteration, employing the RAP (Reduced Adjoining Protonation) labeling scheme, which yields random protonation at non-exchangeable sites. We present here a systematic study on the optimal degree of random sidechain protonation in RAP samples as a function of the MAS (magic angle spinning) frequency. In particular, we compare {sup 1}H sensitivity and linewidth of a microcrystalline protein, the SH3 domain of chicken {alpha}-spectrin, for samples, prepared with 5-25 % H{sub 2}O in the E. coli growth medium, in the MAS frequency range of 20-60 kHz. At an external field of 19.96 T (850 MHz), we find that using a proton concentration between 15 and 25 % in the M9 medium yields the best compromise in terms of sensitivity and resolution, with an achievable average {sup 1}H linewidth on the order of 40-50 Hz. Comparing sensitivities at a MAS frequency of 60 versus 20 kHz, a gain in sensitivity by a factor of 4-4.5 is observed in INEPT-based {sup 1}H detected 1D {sup 1}H,{sup 13}C correlation experiments. In total, we find that spectra recorded with a 1.3 mm rotor at 60 kHz have almost the same sensitivity as spectra recorded with a fully packed 3.2 mm rotor at 20 kHz, even though {approx}20 Multiplication-Sign less material is employed. The improved sensitivity is attributed to {sup 1}H line narrowing due to fast MAS and to the increased efficiency of the 1.3 mm coil.

  11. 2D heterodyne-detected sum frequency generation study on the ultrafast vibrational dynamics of H{sub 2}O and HOD water at charged interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Ken-ichi; Singh, Prashant C. [Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Nihonyanagi, Satoshi; Tahara, Tahei, E-mail: tahei@riken.jp [Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yamaguchi, Shoichi [Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Applied Chemistry, Saitama University, 255 Shimo-Okubo, Saitama 338-8570 (Japan)

    2015-06-07

    Two-dimensional heterodyne-detected vibrational sum-frequency generation (2D HD-VSFG) spectroscopy is applied to study the ultrafast vibrational dynamics of water at positively charged aqueous interfaces, and 2D HD-VSFG spectra of cetyltrimethylammonium bromide (CTAB)/water interfaces in the whole hydrogen-bonded OH stretch region (3000 cm{sup −1} ≤ ω{sub pump} ≤ 3600 cm{sup −1}) are measured. 2D HD-VSFG spectrum of the CTAB/isotopically diluted water (HOD-D{sub 2}O) interface exhibits a diagonally elongated bleaching lobe immediately after excitation, which becomes round with a time constant of ∼0.3 ps due to spectral diffusion. In contrast, 2D HD-VSFG spectrum of the CTAB/H{sub 2}O interface at 0.0 ps clearly shows two diagonal peaks and their cross peaks in the bleaching region, corresponding to the double peaks observed at 3230 cm{sup −1} and 3420 cm{sup −1} in the steady-state HD-VSFG spectrum. Horizontal slices of the 2D spectrum show that the relative intensity of the two peaks of the bleaching at the CTAB/H{sub 2}O interface gradually change with the change of the pump frequency. We simulate the pump-frequency dependence of the bleaching feature using a model that takes account of the Fermi resonance and inhomogeneity of the OH stretch vibration, and the simulated spectra reproduce the essential features of the 2D HD-VSFG spectra of the CTAB/H{sub 2}O interface. The present study demonstrates that heterodyne detection of the time-resolved VSFG is critically important for studying the ultrafast dynamics of water interfaces and for unveiling the underlying mechanism.

  12. Soil-embedded optical fiber sensing cable interrogated by Brillouin optical time-domain reflectometry (B-OTDR) and optical frequency-domain reflectometry (OFDR) for embedded cavity detection and sinkhole warning system

    International Nuclear Information System (INIS)

    Lanticq, V; Bourgeois, E; Delepine-Lesoille, S; Magnien, P; Dieleman, L; Vinceslas, G; Sang, A

    2009-01-01

    A soil-embedded optical fiber sensing cable is evaluated for an embedded cavity detection and sinkhole warning system in railway tunnels. Tests were performed on a decametric structure equipped with an embedded 110 m long fiber optic cable. Both Brillouin optical time-domain reflectometry (B-OTDR) and optical frequency-domain reflectometry (OFDR) sensing techniques were used for cable interrogation, yielding results that were in good qualitative agreement with finite-element calculations. Theoretical and experimental comparison enabled physical interpretation of the influence of ground properties, and the analysis of embedded cavity size and position. A 5 mm embedded cavity located 2 m away from the sensing cable was detected. The commercially available sensing cable remained intact after soil collapse. Specificities of each technique are analyzed in view of the application requirements. For tunnel monitoring, the OFDR technique was determined to be more viable than the B-OTDR due to higher spatial resolution, resulting in better detection and size determination of the embedded cavities. Conclusions of this investigation gave outlines for future field use of distributed strain-sensing methods under railways and more precisely enabled designing a warning system suited to the Ebersviller tunnel specificities

  13. Frequency of Chlamydia trachomatis among male patients with urethritis in northeast of Iran detected by polymerase chain reaction

    Directory of Open Access Journals (Sweden)

    Kiarash Ghazvini

    2012-01-01

    Full Text Available Planning for appropriate preventive measures against Chlamydia trachomatis, a common cause of sexually transmitted disease, requires knowledge of prevalence of infection so that interventions can be targeted in a cost-effective manner. This study was performed on 178 male patients presenting with urethritis in the Mashhad province to determine the prevalence of chlamydial infection in Northeast Iran. A cotton swab and first voided urine specimen were collected according to standard procedures. Polymerase chain reaction (PCR tests were used for the detection of C. trachomatis in the specimens collected and the results were analyzed using SPSS program. Results showed that 10.6% of male patients in this group were infected with C. trachomatis. This study provides strong evidence that prevalence of Chlamydia in the Northeast Iran is high and suggests that Chlamydia screening as a routine part of STD investigations is highly necessary in this area.

  14. Lipa, B. et al. Tsunami Arrival Detection with High Frequency (HF Radar. Remote Sens. 2012, 4, 1448-1461

    Directory of Open Access Journals (Sweden)

    Donald Barrick

    2012-11-01

    Full Text Available We neglected to state that the radar data from Tokushima and Anan is owned by the Ministry of Land, Infrastructure, Transport and Tourism, Shikoku Regional Development Bureau, Komatsushima port and airport office, Japan. Lipa et al. [1] describe results on tsunami detection using data measured by two radars located at Tokushima and Anan on the Kii channel. This data is owned by the Ministry of Land, Infrastructure, Transport and Tourism, Shikoku Regional Development Bureau, Komatsushima port and airport office, Japan. Locations of the radars are shown in Figure 4(a,c [1]. Results of the data analysis are given in Section 3.1.2, plotted in Figure 6 and listed in Table 1 [1].

  15. Gamma-Ray Loudness, Synchrotron Peak Frequency, and Parsec-scale Properties of Blazars Detected by the Fermi Large Area Telescope

    Science.gov (United States)

    Linford, J. D.; Taylor, G. B.; Schinzel, F. K.

    2012-09-01

    The parsec-scale radio properties of 232 active galactic nuclei, most of which are blazars, detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA) at 5 GHz. Data from both the first 11 months (1FGL) and the first 2 years (2FGL) of the Fermi mission were used to investigate these sources' γ-ray properties. We use the ratio of the γ-ray-to-radio luminosity as a measure of γ-ray loudness. We investigate the relationship of several radio properties to γ-ray loudness and to the synchrotron peak frequency. There is a tentative correlation between γ-ray loudness and synchrotron peak frequency for BL Lac objects in both 1FGL and 2FGL, and for flat-spectrum radio quasars (FSRQs) in 2FGL. We find that the apparent opening angle tentatively correlates with γ-ray loudness for FSRQs, but only when we use the 2FGL data. We also find that the total VLBA flux density correlates with the synchrotron peak frequency for BL Lac objects and FSRQs. The core brightness temperature also correlates with synchrotron peak frequency, but only for the BL Lac objects. The low-synchrotron-peaked (LSP) BL Lac object sample shows indications of contamination by FSRQs which happen to have undetectable emission lines. There is evidence that the LSP BL Lac objects are more strongly beamed than the rest of the BL Lac object population.

  16. GAMMA-RAY LOUDNESS, SYNCHROTRON PEAK FREQUENCY, AND PARSEC-SCALE PROPERTIES OF BLAZARS DETECTED BY THE FERMI LARGE AREA TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Linford, J. D.; Taylor, G. B.; Schinzel, F. K., E-mail: jlinford@unm.edu [Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131-0001 (United States)

    2012-09-20

    The parsec-scale radio properties of 232 active galactic nuclei, most of which are blazars, detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA) at 5 GHz. Data from both the first 11 months (1FGL) and the first 2 years (2FGL) of the Fermi mission were used to investigate these sources' {gamma}-ray properties. We use the ratio of the {gamma}-ray-to-radio luminosity as a measure of {gamma}-ray loudness. We investigate the relationship of several radio properties to {gamma}-ray loudness and to the synchrotron peak frequency. There is a tentative correlation between {gamma}-ray loudness and synchrotron peak frequency for BL Lac objects in both 1FGL and 2FGL, and for flat-spectrum radio quasars (FSRQs) in 2FGL. We find that the apparent opening angle tentatively correlates with {gamma}-ray loudness for FSRQs, but only when we use the 2FGL data. We also find that the total VLBA flux density correlates with the synchrotron peak frequency for BL Lac objects and FSRQs. The core brightness temperature also correlates with synchrotron peak frequency, but only for the BL Lac objects. The low-synchrotron-peaked (LSP) BL Lac object sample shows indications of contamination by FSRQs which happen to have undetectable emission lines. There is evidence that the LSP BL Lac objects are more strongly beamed than the rest of the BL Lac object population.

  17. GAMMA-RAY LOUDNESS, SYNCHROTRON PEAK FREQUENCY, AND PARSEC-SCALE PROPERTIES OF BLAZARS DETECTED BY THE FERMI LARGE AREA TELESCOPE

    International Nuclear Information System (INIS)

    Linford, J. D.; Taylor, G. B.; Schinzel, F. K.

    2012-01-01

    The parsec-scale radio properties of 232 active galactic nuclei, most of which are blazars, detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA) at 5 GHz. Data from both the first 11 months (1FGL) and the first 2 years (2FGL) of the Fermi mission were used to investigate these sources' γ-ray properties. We use the ratio of the γ-ray-to-radio luminosity as a measure of γ-ray loudness. We investigate the relationship of several radio properties to γ-ray loudness and to the synchrotron peak frequency. There is a tentative correlation between γ-ray loudness and synchrotron peak frequency for BL Lac objects in both 1FGL and 2FGL, and for flat-spectrum radio quasars (FSRQs) in 2FGL. We find that the apparent opening angle tentatively correlates with γ-ray loudness for FSRQs, but only when we use the 2FGL data. We also find that the total VLBA flux density correlates with the synchrotron peak frequency for BL Lac objects and FSRQs. The core brightness temperature also correlates with synchrotron peak frequency, but only for the BL Lac objects. The low-synchrotron-peaked (LSP) BL Lac object sample shows indications of contamination by FSRQs which happen to have undetectable emission lines. There is evidence that the LSP BL Lac objects are more strongly beamed than the rest of the BL Lac object population.

  18. Detection of the pedogenic magnetic fraction in volcanic soils developed on basalts using frequency-dependent magnetic susceptibility: comparison of two instruments

    Science.gov (United States)

    Grison, Hana; Petrovsky, Eduard; Kapicka, Ales; Hanzlikova, Hana

    2017-05-01

    In studies of the magnetic properties of soils, the frequency-dependent magnetic susceptibility percentage (χFD%) is often used for the identification of ultrafine magnetically superparamagnetic/stable single-domain (SP/SSD) particles. This parameter is commonly used as an indicator for increased pedogenesis. In strongly magnetic soils, the SP/SSD magnetic signal (mostly bio-pedogenic) may be masked by lithological signals; making pedogenesis hard to detect. In this study, we compare results for the detection of ultrafine SP/SSD magnetic particles in andic soils using two instruments: a Bartington MS2B dual-frequency meter and an AGICO Kappabridge MFK1-FA. In particular, the study focuses on the effect of pedogenesis by investigating the relationship between specific soil magnetic and chemical properties (soil organic carbon and pHH2O). The values of χFD% obtained with the MS2B varied from 2.4 to 5.9 per cent, and mass-specific magnetic susceptibility (χLF) from 283 to 1688 × 10-8 m3 kg-1, while values of χFD% and χLF obtained with the MFK1-FA varied from 2.7 to 8.2 per cent and from 299 to 1859 × 10-8 m3 kg-1, respectively. Our results suggest that the detection of the SP/SSD magnetic fraction can be accomplished by comparing relative trends of χFD% along the soil profile. Moreover, the discrimination between bio-pedogenic and lithogenic magnetic contributions in the SP/SSD fraction is possible by comparing the χFD% and χLF data determined in the fine earth (<2 mm) and the coarse fraction (4-10 mm) samples down the soil profile.

  19. Skeletal metastasis as detected by 18F-FDG PET with negative CT of the PET/CT: Frequency and impact on cancer staging and or management

    Directory of Open Access Journals (Sweden)

    Fatma Ahmed

    2016-10-01

    Full Text Available Objectives: The aim of our study is to assess the frequency of detection of PET positive CT negative skeletal metastases (SM and determine the impact of such detection on staging and/or management in patients who had FDG PET/CT as part of the cancer work up.Methods: We retrospectively reviewed 2000 18F-FDG PET/CT scans of known cancer patients. A log was kept to record cases of suspected SM with or without bone changes from the low-dose non-contrast CT. The presence or absence of SM was evaluated based on available pathological and clinical data. The impact of detection of such lesions on cancer staging and/or management was evaluated by a board certified oncologist.Results: Of the 2000 cases, 18F-FDG PET/CT suggested SM in 146/2000 (7.3%. Of those 146 cases, 105 (72% were positive on both PET and CT. The remaining 41 (28% had PET positive CT negative bone lesions. SM was confirmed in 36/41 (88% PET positive/CT negative cases. This was based on biopsy, imaging or clinical follow-up. The detection of PET positive CT negative SM did not change staging or management in 7/36 (19.4%. However, staging and/or management was affected in 29/36 (80.6%. Conclusions: SM is not uncommon in 18F-FDG PET/CT, as it accounts for 146/2000 (7.3% of cases. PET demonstrated FDG-avid SM without a CT abnormality in at least 36/146 (25%. Patients staging and or management changed in 29/36 (80.5%. We concluded that 18F-FDG PET is sensitive in detection of SM with significant impact on staging & or management. Key words18F-FDG PET/CT, Skeletal metastasis, PET positive, CT negative

  20. Frequency of suspected cases of neurocysticercosis detected by computed skull tomography in Santa Maria, Rio Grande do Sul State, Brazil

    International Nuclear Information System (INIS)

    Silva, Jose Edson Paz da

    2000-01-01

    Due to the lack of studies about neurocysticercosis in the South of Brazil, an investigation was conducted to determine the percentage cases of neurocysticercosis in computed tomography diagnoses in Santa Maria, RS, from January 1997 to December 1998. Of 6300 computed tomographs (CT) of the skull performed at the private Hospital de Caridade Astrogildo de Azevedo, 80, i.e. 1.27% were suspected of neurocysticercosis. Fifty were women (62.5%) and 30 were men (37.5). The most frequent radiological manifestation indicating neurocysticercosis was the presence of calcifications (isolated or associated), with a 95% rate (76 cases), while the presence of hypodense lesions reached a 5% rate (4 cases). After routine analysis, each CT was evaluated again and the suspected cases were confirmed. The percentage of suspected cases of neurocysticercosis detected by CT in the present study carried out in santa Maria was considered low (1.27%). This can be explained by the fact that tomography is not accessible to the economically underprivileged population of Santa Maria. We hope that the present study can alert the population and the professionals to the fact neurocysticercosis is a more frequent disease than indicated by the few diagnoses made. (author)

  1. Frequency of suspected cases of neurocysticercosis detected by computed skull tomography in Santa Maria, Rio Grande do Sul State, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jose Edson Paz da [Santa Maria Univ., RS (Brazil). Dept. de Analises Clinicas e Toxicologicas; Diefenthaeler, Ana Paula [Santa Maria Univ., RS (Brazil). Curso de Farmacia e Bioquimica; Palma, Jose Knoll [Hospital de Caridade Astrogildo de Azevedo, Santa Maria, RS (Brazil)

    2000-02-01

    Due to the lack of studies about neurocysticercosis in the South of Brazil, an investigation was conducted to determine the percentage cases of neurocysticercosis in computed tomography diagnoses in Santa Maria, RS, from January 1997 to December 1998. Of 6300 computed tomographs (CT) of the skull performed at the private Hospital de Caridade Astrogildo de Azevedo, 80, i.e. 1.27% were suspected of neurocysticercosis. Fifty were women (62.5%) and 30 were men (37.5). The most frequent radiological manifestation indicating neurocysticercosis was the presence of calcifications (isolated or associated), with a 95% rate (76 cases), while the presence of hypodense lesions reached a 5% rate (4 cases). After routine analysis, each CT was evaluated again and the suspected cases were confirmed. The percentage of suspected cases of neurocysticercosis detected by CT in the present study carried out in santa Maria was considered low (1.27%). This can be explained by the fact that tomography is not accessible to the economically underprivileged population of Santa Maria. We hope that the present study can alert the population and the professionals to the fact neurocysticercosis is a more frequent disease than indicated by the few diagnoses made. (author)

  2. Detection of high frequency of mutations in a breast and/or ovarian cancer cohort: implications of embracing a multi-gene panel in molecular diagnosis in India.

    Science.gov (United States)

    Mannan, Ashraf U; Singh, Jaya; Lakshmikeshava, Ravikiran; Thota, Nishita; Singh, Suhasini; Sowmya, T S; Mishra, Avshesh; Sinha, Aditi; Deshwal, Shivani; Soni, Megha R; Chandrasekar, Anbukayalvizhi; Ramesh, Bhargavi; Ramamurthy, Bharat; Padhi, Shila; Manek, Payal; Ramalingam, Ravi; Kapoor, Suman; Ghosh, Mithua; Sankaran, Satish; Ghosh, Arunabha; Veeramachaneni, Vamsi; Ramamoorthy, Preveen; Hariharan, Ramesh; Subramanian, Kalyanasundaram

    2016-06-01

    Breast and/or ovarian cancer (BOC) are among the most frequently diagnosed forms of hereditary cancers and leading cause of death in India. This emphasizes on the need for a cost-effective method for early detection of these cancers. We sequenced 141 unrelated patients and families with BOC using the TruSight Cancer panel, which includes 13 genes strongly associated with risk of inherited BOC. Multi-gene sequencing was done on the Illumina MiSeq platform. Genetic variations were identified using the Strand NGS software and interpreted using the StrandOmics platform. We were able to detect pathogenic mutations in 51 (36.2%) cases, out of which 19 were novel mutations. When we considered familial breast cancer cases only, the detection rate increased to 52%. When cases were stratified based on age of diagnosis into three categories, ⩽40 years, 40-50 years and >50 years, the detection rates were higher in the first two categories (44.4% and 53.4%, respectively) as compared with the third category, in which it was 26.9%. Our study suggests that next-generation sequencing-based multi-gene panels increase the sensitivity of mutation detection and help in identifying patients with a high risk of developing cancer as compared with sequential tests of individual genes.

  3. Sensitivity to Regional Earthquake Triggering and Magnitude-Frequency Characteristics of Microseismicity Detected via Matched-Filter Analysis, Central Southern Alps, New Zealand

    Science.gov (United States)

    Boese, C. M.; Townend, J.; Chamberlain, C. J.; Warren-Smith, E.

    2016-12-01

    Microseismicity recorded since 2008 by the Southern Alps Microseismicity Borehole Array (SAMBA) and other predominantly short-period seismic networks deployed in the central Southern Alps, New Zealand, reveals distinctive patterns of triggering in response to regional seismicity (magnitudes larger than 5, epicentral distances of 100-500 km). Using matched-filter detection methods implemented in the EQcorrscan package (Chamberlain et al., in prep.), we analyze microseismicity occurring in several geographically distinct swarms in order to examine the responses of specific microearthquake sources to earthquakes of different sizes occurring at different distances and azimuths. The swarms exhibit complex responses to regional seismicity which reveal that microearthquake triggering in these cases involves a combination of extrinsic factors (related to the dynamic stresses produced by the regional earthquake) and intrinsic factors (controlled by the local state of stress and possibly by hydrogeological processes). We find also that the microearthquakes detected by individual templates have Gutenberg-Richter magnitude-frequency characteristics. Since the detected events, by design, have very similar hypocentres and focal mechanisms, the observed scaling pertains to a restricted set of fault planes.

  4. Gait Event Detection in Real-World Environment for Long-Term Applications: Incorporating Domain Knowledge Into Time-Frequency Analysis.

    Science.gov (United States)

    Khandelwal, Siddhartha; Wickstrom, Nicholas

    2016-12-01

    Detecting gait events is the key to many gait analysis applications that would benefit from continuous monitoring or long-term analysis. Most gait event detection algorithms using wearable sensors that offer a potential for use in daily living have been developed from data collected in controlled indoor experiments. However, for real-word applications, it is essential that the analysis is carried out in humans' natural environment; that involves different gait speeds, changing walking terrains, varying surface inclinations and regular turns among other factors. Existing domain knowledge in the form of principles or underlying fundamental gait relationships can be utilized to drive and support the data analysis in order to develop robust algorithms that can tackle real-world challenges in gait analysis. This paper presents a novel approach that exhibits how domain knowledge about human gait can be incorporated into time-frequency analysis to detect gait events from long-term accelerometer signals. The accuracy and robustness of the proposed algorithm are validated by experiments done in indoor and outdoor environments with approximately 93 600 gait events in total. The proposed algorithm exhibits consistently high performance scores across all datasets in both, indoor and outdoor environments.

  5. Generation of poly-β-hydroxybutyrate from acetate in higher plants: Detection of acetoacetyl CoA reductase- and PHB synthase- activities in rice.

    Science.gov (United States)

    Tsuda, Hirohisa; Shiraki, Mari; Inoue, Eri; Saito, Terumi

    2016-08-20

    It has been reported that Poly-β-hydroxybutyrate (PHB) is generated from acetate in the rice root. However, no information is available about the biosynthetic pathway of PHB from acetate in plant cells. In the bacterium Ralstonia eutropha H16 (R. eutropha), PHB is synthesized from acetyl CoA by the consecutive reaction of three enzymes: β-ketothiolase (EC: 2.3.1.9), acetoacetyl CoA reductase (EC: 1.1.1.36) and PHB synthase (EC: 2.3.1.-). Thus, in this study, we examined whether the above three enzymatic activities were also detected in rice seedlings. The results clearly showed that the activities of the above three enzymes were all detected in rice. In particular, the PHB synthase activity was detected specifically in the sonicated particulate fractions (2000g 10min precipitate (ppt) and the 8000g 30min ppt) of rice roots and leaves. In addition to these enzyme activities, several new experimental results were obtained on PHB synthesis in higher plants: (a) (14)C-PHB generated from 2-(14)C-acetate was mainly localized in the 2000g 10min ppt and the 8000g 30min ppt of rice root. (b) Addition of acetate (0.1-10mM) to culture medium of rice seedlings did not increase the content of PHB in the rice root or leaf. (c) In addition to C3 plants, PHB was generated from acetate in a C4 plant (corn) and in a CAM plant (Bryophyllum pinnatum). d) Washing with ethylenediaminetetraacetic acid (EDTA) strongly suggested that the PHB synthesized from acetate was of plant origin and was not bacterial contamination. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. Higher-order statistical moments and a procedure that detects potentially anomalous years as two alternative methods describing alterations in continuous environmental data

    Science.gov (United States)

    Arismendi, Ivan; Johnson, Sherri L.; Dunham, Jason B.

    2015-01-01

    Statistics of central tendency and dispersion may not capture relevant or desired characteristics of the distribution of continuous phenomena and, thus, they may not adequately describe temporal patterns of change. Here, we present two methodological approaches that can help to identify temporal changes in environmental regimes. First, we use higher-order statistical moments (skewness and kurtosis) to examine potential changes of empirical distributions at decadal extents. Second, we adapt a statistical procedure combining a non-metric multidimensional scaling technique and higher density region plots to detect potentially anomalous years. We illustrate the use of these approaches by examining long-term stream temperature data from minimally and highly human-influenced streams. In particular, we contrast predictions about thermal regime responses to changing climates and human-related water uses. Using these methods, we effectively diagnose years with unusual thermal variability and patterns in variability through time, as well as spatial variability linked to regional and local factors that influence stream temperature. Our findings highlight the complexity of responses of thermal regimes of streams and reveal their differential vulnerability to climate warming and human-related water uses. The two approaches presented here can be applied with a variety of other continuous phenomena to address historical changes, extreme events, and their associated ecological responses.

  7. Lessons derived from two high-frequency sea level events in the Atlantic: implications for coastal risk analysis and tsunami detection

    Directory of Open Access Journals (Sweden)

    Begoña Pérez-Gómez

    2016-11-01

    Full Text Available The upgrade and enhancement of sea level networks worldwide for integration in sea level hazard warning systems have significantly increased the possibilities for measuring and analyzing high frequency sea level oscillations, with typical periods ranging from a few minutes to a few hours. Many tide gauges now afford 1 min or more frequent sampling and have shown such events to be a common occurrence. Their origins and spatial distribution are diverse and must be well understood in order to correctly design and interpret, for example, the automatic detection algorithms used by tsunami warning centers. Two events recorded recently in European Atlantic waters are analyzed here: possible wave-induced seiches that occurred along the North coast of Spain during the storms of January and February of 2014, and oscillations detected after an earthquake in the mid-Atlantic the 13th of February of 2015. The former caused significant flooding in towns and villages and a huge increase in wave-induced coastal damage that was reported in the media for weeks. The second was a smaller signal present in several tide gauges along the Atlantic coast that, that coincided with the occurrence of this earthquake, leading to a debate on the potential detection of a very small tsunami and how it might yield significant information for tsunami wave modelers and for the development of tsunami detection software. These kinds of events inform us about the limitations of automatic algorithms for tsunami warning and help to improve the information provided to tsunami warning centers, whilst also emphasizing the importance of other forcings in generating extreme sea levels and their associated potential for causing damage to infrastructure.

  8. Real-time monitoring of focused ultrasound blood-brain barrier opening via subharmonic acoustic emission detection: implementation of confocal dual-frequency piezoelectric transducers

    Science.gov (United States)

    Tsai, Chih-Hung; Zhang, Jia-Wei; Liao, Yi-Yi; Liu, Hao-Li

    2016-04-01

    Burst-tone focused ultrasound exposure in the presence of microbubbles has been demonstrated to be effective at inducing temporal and local opening of the blood-brain barrier (BBB), which promises significant clinical potential to deliver therapeutic molecules into the central nervous system (CNS). Traditional contrast-enhanced imaging confirmation after focused ultrasound (FUS) exposure serves as a post-operative indicator of the effectiveness of FUS-BBB opening, however, an indicator that can concurrently report the BBB status and BBB-opening effectiveness is required to provide effective feedback to implement this treatment clinically. In this study, we demonstrate the use of subharmonic acoustic emission detection with implementation on a confocal dual-frequency piezoelectric ceramic structure to perform real-time monitoring of FUS-BBB opening. A confocal dual-frequency (0.55 MHz/1.1 MHz) focused ultrasound transducer was designed. The 1.1 MHz spherically-curved ceramic was employed to deliver FUS exposure to induce BBB-opening, whereas the outer-ring 0.55 MHz ceramic was employed to detect the subharmonic acoustic emissions originating from the target position. In stage-1 experiments, we employed spectral analysis and performed an energy spectrum density (ESD) calculation. An optimized 0.55 MHz ESD level change was shown to effectively discriminate the occurrence of BBB-opening. Wideband acoustic emissions received from 0.55 MHz ceramics were also analyzed to evaluate its correlations with erythrocyte extravasations. In stage-2 real-time monitoring experiments, we applied the predetermined ESD change as a detection threshold in PC-controlled algorithm to predict the FUS exposure intra-operatively. In stage-1 experiment, we showed that subharmonic ESD presents distinguishable dynamics between intact BBB and opened BBB, and therefore a threshold ESD change level (5.5 dB) can be identified for BBB-opening prediction. Using this ESD change threshold detection as a

  9. Real-time monitoring of focused ultrasound blood-brain barrier opening via subharmonic acoustic emission detection: implementation of confocal dual-frequency piezoelectric transducers

    International Nuclear Information System (INIS)

    Tsai, Chih-Hung; Zhang, Jia-Wei; Liao, Yi-Yi; Liu, Hao-Li

    2016-01-01

    Burst-tone focused ultrasound exposure in the presence of microbubbles has been demonstrated to be effective at inducing temporal and local opening of the blood-brain barrier (BBB), which promises significant clinical potential to deliver therapeutic molecules into the central nervous system (CNS). Traditional contrast-enhanced imaging confirmation after focused ultrasound (FUS) exposure serves as a post-operative indicator of the effectiveness of FUS-BBB opening, however, an indicator that can concurrently report the BBB status and BBB-opening effectiveness is required to provide effective feedback to implement this treatment clinically. In this study, we demonstrate the use of subharmonic acoustic emission detection with implementation on a confocal dual-frequency piezoelectric ceramic structure to perform real-time monitoring of FUS-BBB opening. A confocal dual-frequency (0.55 MHz/1.1 MHz) focused ultrasound transducer was designed. The 1.1 MHz spherically-curved ceramic was employed to deliver FUS exposure to induce BBB-opening, whereas the outer-ring 0.55 MHz ceramic was employed to detect the subharmonic acoustic emissions originating from the target position. In stage-1 experiments, we employed spectral analysis and performed an energy spectrum density (ESD) calculation. An optimized 0.55 MHz ESD level change was shown to effectively discriminate the occurrence of BBB-opening. Wideband acoustic emissions received from 0.55 MHz ceramics were also analyzed to evaluate its correlations with erythrocyte extravasations. In stage-2 real-time monitoring experiments, we applied the predetermined ESD change as a detection threshold in PC-controlled algorithm to predict the FUS exposure intra-operatively. In stage-1 experiment, we showed that subharmonic ESD presents distinguishable dynamics between intact BBB and opened BBB, and therefore a threshold ESD change level (5.5 dB) can be identified for BBB-opening prediction. Using this ESD change threshold detection as a

  10. Frequency of left atrial thrombus detected by transesophageal echocardiography in patients of tight mitral stenosis having negative trans-thoracic echocardiography at gulab devi cardiac complex

    International Nuclear Information System (INIS)

    Fayyaz, A.; Iqbal, M.W.

    2014-01-01

    Introduction: Patients with mitral stenosis (MS) having atrial fibrillation (AF) are more prone to develop left atrial (LA) thrombus. Systemic embolism, related to LA thrombus is a well-known risk of Percutaneous Mitral Balloon Valvotomy (PMBV) of the mitral valve. Therefore presence of LA thrombus is a contraindication to PMBV. Objective: Objective of this study was to detect the frequency of LA thrombus by transesophageal echocardiography (TEE) in patients of tight MS in whom transthoracic echocardiography (TTE) could not detect any LA thrombus. Patients and Methods: In this cross sectional study, we took 100 indoor patients with tight MS on non-probability consecutive sampling. Data was collected after meeting inclusion criteria. Patients were taken in this study after acquiring written informed consent. Symptoms were inquired from all patients and functional status was assessed by New York Heart Association class. Unstable patients were medically managed before the procedure. TEE was done on the same day before undergoing PMBV to look for clot in LA. Results: The mean age of the patients was 32.20 years and SD was 11.3 years. There were 36(36%) male patients and 64(64%) female patients. LA thrombus was present in 40% of patients on TEE out of which 19 were male patients (52.77%) and 21 were female patients (32.81%). Conclusion: Patients with mitral stenosis having AF are more prone to develop LA thrombus. In this study, the frequency of LA thrombus was 40% recorded, which is high. Due to the potential risk of embolization, it is strongly recommended to perform TEE in patients with normal TTE study before undergoing PMBV. The presence of a LA thrombus should be considered a contraindication to the PMBV of the mitral valve. (author)

  11. Detecting vocal fatigue in student singers using acoustic measures of mean fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio

    Science.gov (United States)

    Sisakun, Siphan

    2000-12-01

    The purpose of this study is to explore the ability of four acoustic parameters, mean fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio, to detect vocal fatigue in student singers. The participants are 15 voice students, who perform two distinct tasks, data collection task and vocal fatiguing task. The data collection task includes the sustained vowel /a/, reading a standard passage, and self-rate on a vocal fatigue form. The vocal fatiguing task is the vocal practice of musical scores for a total of 45 minutes. The four acoustic parameters are extracted using the software EZVoicePlus. The data analyses are performed to answer eight research questions. The first four questions relate to correlations of the self-rating scale and each of the four parameters. The next four research questions relate to differences in the parameters over time using one-factor repeated measures analysis of variance (ANOVA). The result yields a proposed acoustic profile of vocal fatigue in student singers. This profile is characterized by increased fundamental frequency; slightly decreased jitter; slightly decreased shimmer; and slightly increased harmonics-to-noise ratio. The proposed profile requires further investigation.

  12. Adding a dimension to the infrared spectra of interfaces using heterodyne detected 2D sum-frequency generation (HD 2D SFG) spectroscopy.

    Science.gov (United States)

    Xiong, Wei; Laaser, Jennifer E; Mehlenbacher, Randy D; Zanni, Martin T

    2011-12-27

    In the last ten years, two-dimensional infrared spectroscopy has become an important technique for studying molecular structures and dynamics. We report the implementation of heterodyne detected two-dimensional sum-frequency generation (HD 2D SFG) spectroscopy, which is the analog of 2D infrared (2D IR) spectroscopy, but is selective to noncentrosymmetric systems such as interfaces. We implement the technique using mid-IR pulse shaping, which enables rapid scanning, phase cycling, and automatic phasing. Absorptive spectra are obtained, that have the highest frequency resolution possible, from which we extract the rephasing and nonrephasing signals that are sometimes preferred. Using this technique, we measure the vibrational mode of CO adsorbed on a polycrystalline Pt surface. The 2D spectrum reveals a significant inhomogenous contribution to the spectral line shape, which is quantified by simulations. This observation indicates that the surface conformation and environment of CO molecules is more complicated than the simple "atop" configuration assumed in previous work. Our method can be straightforwardly incorporated into many existing SFG spectrometers. The technique enables one to quantify inhomogeneity, vibrational couplings, spectral diffusion, chemical exchange, and many other properties analogous to 2D IR spectroscopy, but specifically for interfaces.

  13. Detection of high-sensitivity troponin in outpatients with stable pulmonary hypertension identifies a subgroup at higher risk of adverse outcomes.

    Science.gov (United States)

    Roy, Andrew K; McCullagh, Brian N; Segurado, Ricardo; McGorrian, Catherine; Keane, Elizabeth; Keaney, John; Fitzgibbon, Maria N; Mahon, Niall G; Murray, Patrick T; Gaine, Sean P

    2014-01-01

    The detection of elevations in cardiorenal biomarkers, such as troponins, B-type natriuretic peptides (BNPs), and neutrophil gelatinase-associated lipocalins, are associated with poor outcomes in patients hospitalized with acute heart failure. Less is known about the association of these markers with adverse events in chronic right ventricular dysfunction due to pulmonary hypertension, or whether their measurement may improve risk assessment in the outpatient setting. We performed a cohort study of 108 patients attending the National Pulmonary Hypertension Unit in Dublin, Ireland, from 2007 to 2009. Cox proportional hazards analysis and receiver operating characteristic curves were used to determine predictors of mortality and hospitalization. Death or hospitalization occurred in 50 patients (46.3%) during the median study period of 4.1 years. Independent predictors of mortality were: 1) decreasing 6-minute walk test (6MWT; hazard ratio [HR] 12.8; P < .001); 2) BNP (HR 6.68; P < .001); and 3) highly sensitive troponin (hsTnT; HR 5.48; P < .001). Adjusted hazard analyses remained significant when hsTnT was added to a model with BNP and 6MWT (HR 9.26, 95% CI 3.61-23.79), as did the predictive ability of the model for death and rehospitalization (area under the receiver operating characteristic curve 0.81, 95% CI 0.73-0.90). Detection of troponin using a highly sensitive assay identifies a pulmonary hypertension subgroup with a poorer prognosis. hsTnT may also be used in a risk prediction model to identify patients at higher risk who may require escalation of targeted pulmonary vasodilator therapies and closer clinical surveillance. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Tsunami detection by high-frequency radar in British Columbia: performance assessment of the time-correlation algorithm for synthetic and real events

    Science.gov (United States)

    Guérin, Charles-Antoine; Grilli, Stéphan T.; Moran, Patrick; Grilli, Annette R.; Insua, Tania L.

    2018-02-01

    The authors recently proposed a new method for detecting tsunamis using high-frequency (HF) radar observations, referred to as "time-correlation algorithm" (TCA; Grilli et al. Pure Appl Geophys 173(12):3895-3934, 2016a, 174(1): 3003-3028, 2017). Unlike standard algorithms that detect surface current patterns, the TCA is based on analyzing space-time correlations of radar signal time series in pairs of radar cells, which does not require inverting radial surface currents. This was done by calculating a contrast function, which quantifies the change in pattern of the mean correlation between pairs of neighboring cells upon tsunami arrival, with respect to a reference correlation computed in the recent past. In earlier work, the TCA was successfully validated based on realistic numerical simulations of both the radar signal and tsunami wave trains. Here, this algorithm is adapted to apply to actual data from a HF radar installed in Tofino, BC, for three test cases: (1) a simulated far-field tsunami generated in the Semidi Subduction Zone in the Aleutian Arc; (2) a simulated near-field tsunami from a submarine mass failure on the continental slope off of Tofino; and (3) an event believed to be a meteotsunami, which occurred on October 14th, 2016, off of the Pacific West Coast and was measured by the radar. In the first two cases, the synthetic tsunami signal is superimposed onto the radar signal by way of a current memory term; in the third case, the tsunami signature is present within the radar data. In light of these test cases, we develop a detection methodology based on the TCA, using a correlation contrast function, and show that in all three cases the algorithm is able to trigger a timely early warning.

  15. Tsunami detection by high-frequency radar in British Columbia: performance assessment of the time-correlation algorithm for synthetic and real events

    Science.gov (United States)

    Guérin, Charles-Antoine; Grilli, Stéphan T.; Moran, Patrick; Grilli, Annette R.; Insua, Tania L.

    2018-05-01

    The authors recently proposed a new method for detecting tsunamis using high-frequency (HF) radar observations, referred to as "time-correlation algorithm" (TCA; Grilli et al. Pure Appl Geophys 173(12):3895-3934, 2016a, 174(1): 3003-3028, 2017). Unlike standard algorithms that detect surface current patterns, the TCA is based on analyzing space-time correlations of radar signal time series in pairs of radar cells, which does not require inverting radial surface currents. This was done by calculating a contrast function, which quantifies the change in pattern of the mean correlation between pairs of neighboring cells upon tsunami arrival, with respect to a reference correlation computed in the recent past. In earlier work, the TCA was successfully validated based on realistic numerical simulations of both the radar signal and tsunami wave trains. Here, this algorithm is adapted to apply to actual data from a HF radar installed in Tofino, BC, for three test cases: (1) a simulated far-field tsunami generated in the Semidi Subduction Zone in the Aleutian Arc; (2) a simulated near-field tsunami from a submarine mass failure on the continental slope off of Tofino; and (3) an event believed to be a meteotsunami, which occurred on October 14th, 2016, off of the Pacific West Coast and was measured by the radar. In the first two cases, the synthetic tsunami signal is superimposed onto the radar signal by way of a current memory term; in the third case, the tsunami signature is present within the radar data. In light of these test cases, we develop a detection methodology based on the TCA, using a correlation contrast function, and show that in all three cases the algorithm is able to trigger a timely early warning.

  16. Differential requirements of CD4(+) T-cell signals for effector cytotoxic T-lymphocyte (CTL) priming and functional memory CTL development at higher CD8(+) T-cell precursor frequency.

    Science.gov (United States)

    Umeshappa, Channakeshava S; Nanjundappa, Roopa H; Xie, Yufeng; Freywald, Andrew; Xu, Qingyong; Xiang, Jim

    2013-04-01

    Increased CD8(+) T-cell precursor frequency (PF) precludes the requirement of CD4(+) helper T (Th) cells for primary CD8(+) cytotoxic T-lymphocyte (CTL) responses. However, the key questions of whether unhelped CTLs generated at higher PF are functional effectors, and whether unhelped CTLs can differentiate into functional memory cells at higher PF are unclear. In this study, ovalbumin (OVA) -pulsed dendritic cells (DC(OVA)) derived from C57BL/6, CD40 knockout (CD40(-/-)) or CD40 ligand knockout (CD40L(-/-)) mice were used to immunize C57BL/6, Ia(b-/-), CD40(-/-) or CD40L(-/-) mice, whose PF was previously increased with transfer of 1 × 10(6) CD8(+) T cells derived from OVA-specific T-cell receptor (TCR) transgenic OTI, OTI(CD40(-/-)) or OTI(CD40L(-/-)) mice. All the immunized mice were then assessed for effector and memory CTL responses. Following DC immunization, relatively comparable CTL priming occurred without CD4(+) T-cell help and Th-provided CD40/CD40L signalling. In addition, the unhelped CTLs were functional effectors capable of inducing therapeutic immunity against established OVA-expressing tumours. In contrast, the functional memory development of CTLs was severely impaired in the absence of CD4(+) T-cell help and CD40/CD40L signalling. Finally, unhelped memory CTLs failed to protect mice against lethal tumour challenge. Taken together, these results demonstrate that CD4(+) T-cell help at higher PF, is not required for effector CTL priming, but is required for functional memory CTL development against cancer. Our data may impact the development of novel preventive and therapeutic approaches in cancer patients with compromised CD4(+) T-cell functions. © 2012 Blackwell Publishing Ltd.

  17. Continuous time-resolved regional methane leak detection with on-line background estimation using a novel combination of dual frequency comb laser spectroscopy and atmospheric inversions

    Science.gov (United States)

    Alden, C. B.; Coburn, S.; Wright, R.; Baumann, E.; Cossel, K.; Sweeney, C.; Ghosh, S.; Newbury, N.; Prasad, K.; Coddington, I.; Rieker, G. B.

    2017-12-01

    Advances in natural gas extraction technology have led to increased US production and transport activity, and as a consequence, an increased need for monitoring of methane leaks. Current leak detection methods provide time snapshots, and not continuous, time-varying estimates of emissions. Most approaches also require specific atmospheric conditions, operators, or the use of a tracer gas, requiring site access. Given known intermittency in fugitive methane emissions, continuous monitoring is a critical need for emissions mitigation. We present a novel leak detection method that employs dual frequency comb spectrometry to offer continuous, autonomous, leak detection and quantification over square-km scale areas. The spectrometer is situated in a field of natural gas pads, and a series of retroreflectors around the field direct light back to a detector. The laser light spans 1620-1680 nm with 0.002 nm line spacing, measuring thousands of individual absorption features from multiple species. The result is high-stability trace gas (here CH4, CO2, and H2O) measurements over long (1 km+) open paths through the atmosphere. Measurements are used in an atmospheric inversion to estimate the time variability of emissions at each location of interest. Importantly, the measurement framework and inversion solve explicitly for background concentrations, which vary rapidly in fields of active oil and gas production. We present the results of controlled-leak field tests in rural Colorado. We demonstrate the ability to locate and size a leak located 1 km away from the spectrometer and varying in strength from 1.5 to 7.7 g/min, resulting in mean atmospheric enhancements of 20 ppb. The inversion correctly identifies when the leak turned on and off over a 24-hour period, and determines the mean leak strength to within 10% of the true controlled rate. We further demonstrate the ability of the system to correctly locate and size the start and end of simultaneous 2.7 to 4.8 g/min leaks

  18. HIV exposed seronegative (HESN compared to HIV infected individuals have higher frequencies of telomeric Killer Immunoglobulin-like Receptor (KIR B motifs; Contribution of KIR B motif encoded genes to NK cell responsiveness.

    Directory of Open Access Journals (Sweden)

    Elise Jackson

    Full Text Available Previously, we showed that Killer Immunoglobulin-like Receptor (KIR3DS1 homozygotes (hmz are more frequent in HIV exposed seronegative (HESN than in recently HIV infected (HIV+ individuals. KIR3DS1 encodes an activating Natural Killer (NK cell receptor (NKR. The link between KIR genotype and HIV outcomes likely arises from the function that NK cells acquire through expression of particular NKRs. An initial screen of 97 HESN and 123 HIV+ subjects for the frequency of KIR region gene carriage observed between-group differences for several telomeric KIR region loci. In a larger set of up to 106 HESN and 439 HIV+ individuals, more HESN than HIV+ subjects were KIR3DS1 homozygotes, lacked a full length KIR2DS4 gene and carried the telomeric group B KIR haplotype motif, TB01. TB01 is characterized by the presence of KIR3DS1, KIR2DL5A, KIR2DS3/5 and KIR2DS1, in linkage disequilibrium with each other. We assessed which of the TB01 encoded KIR gene products contributed to NK cell responsiveness by stimulating NK cells from 8 HIV seronegative KIR3DS1 and TB01 motif homozygotes with 721.221 HLA null cells and evaluating the frequency of KIR3DS1+/-KIR2DL5+/-, KIR3DS1+/-KIR2DS1+/-, KIR3DS1+/-KIR2DS5+/- NK cells secreting IFN-γ and/or expressing CD107a. A higher frequency of NK cells expressing, versus not, KIR3DS1 responded to 721.221 stimulation. KIR2DL5A+, KIR2DS1+ and KIR2DS5+ NK cells did not contribute to 721.221 responses or modulate those by KIR3DS1+ NK cells. Thus, of the TB01 KIR gene products, only KIR3DS1 conferred responsiveness to HLA-null stimulation, demonstrating its ligation can activate ex vivo NK cells.

  19. The Role of Radio Frequency Detection System Embedded Surgical Sponges in Preventing Retained Surgical Sponges: A Prospective Evaluation in Patients Undergoing Emergency Surgery.

    Science.gov (United States)

    Inaba, Kenji; Okoye, Obi; Aksoy, Hande; Skiada, Dimitra; Ault, Glenn; Sener, Stephen; Lam, Lydia; Benjamin, Elizabeth; Demetriades, Demetrios

    2016-10-01

    To prospectively evaluate the ability of radio frequency detection (RFD) system-embedded sponges to mitigate the incidence of retained surgical sponges (RSS) after emergency surgery. Emergency surgery patients are at high risk for retained foreign bodies. All emergent trauma and nontrauma cavitary operations over a 5-year period (January 2010-December 2014) were prospectively enrolled. For damage-control procedures, only the definitive closure was included. RFD sponges were used exclusively throughout the study period. Before closure, the sponge and instrument count was followed by RFD scanning and x-ray evaluation for retained sponges. RSS and near-misses averted using the RFD system were analyzed. In all, 2051 patients [median (range)], aged 41 (1-101) years, 72.2% male, 46.8% trauma patients, underwent 2148 operations (1824 laparotomy, 100 thoracotomy, 30 sternotomy, and 97 combined). RFD detected retained sponges in 11 (0.5%) patients (81.8%laparotomy, 18.2% sternotomy) before cavitary closure. All postclosure x-rays were negative. No retained sponges were missed by the RFD system. Body mass index was 29 (23-43), estimated blood loss 1.0 L (0-23), and operating room time 160 minutes (71-869). Procedures started after 18:00 to 06:00 hours in 45.5% of the patients. The sponge count was incorrect in 36.4%, not performed due to time constraints in 45.5%, and correct in 18.2%. The additional cost of using RFD-embedded disposables was $0.17 for a 4X18 laparotomy sponge and $0.46 for a 10 pack of 12ply, 4X8. Emergent surgical procedures are high-risk for retained sponges, even when sponge counts are performed and found to be correct. Implementation of a RFD system was effective in preventing this complication and should be considered for emergent operations in an effort to improve patient safety.

  20. Web Based Rapid Mapping of Disaster Areas using Satellite Images, Web Processing Service, Web Mapping Service, Frequency Based Change Detection Algorithm and J-iView

    Science.gov (United States)

    Bandibas, J. C.; Takarada, S.

    2013-12-01

    Timely identification of areas affected by natural disasters is very important for a successful rescue and effective emergency relief efforts. This research focuses on the development of a cost effective and efficient system of identifying areas affected by natural disasters, and the efficient distribution of the information. The developed system is composed of 3 modules which are the Web Processing Service (WPS), Web Map Service (WMS) and the user interface provided by J-iView (fig. 1). WPS is an online system that provides computation, storage and data access services. In this study, the WPS module provides online access of the software implementing the developed frequency based change detection algorithm for the identification of areas affected by natural disasters. It also sends requests to WMS servers to get the remotely sensed data to be used in the computation. WMS is a standard protocol that provides a simple HTTP interface for requesting geo-registered map images from one or more geospatial databases. In this research, the WMS component provides remote access of the satellite images which are used as inputs for land cover change detection. The user interface in this system is provided by J-iView, which is an online mapping system developed at the Geological Survey of Japan (GSJ). The 3 modules are seamlessly integrated into a single package using J-iView, which could rapidly generate a map of disaster areas that is instantaneously viewable online. The developed system was tested using ASTER images covering the areas damaged by the March 11, 2011 tsunami in northeastern Japan. The developed system efficiently generated a map showing areas devastated by the tsunami. Based on the initial results of the study, the developed system proved to be a useful tool for emergency workers to quickly identify areas affected by natural disasters.

  1. Detection of feline coronavirus in cheetah (Acinonyx jubatus) feces by reverse transcription-nested polymerase chain reaction in cheetahs with variable frequency of viral shedding.

    Science.gov (United States)

    Gaffney, Patricia M; Kennedy, Melissa; Terio, Karen; Gardner, Ian; Lothamer, Chad; Coleman, Kathleen; Munson, Linda

    2012-12-01

    Cheetahs (Acinonyx jubatus) are a highly threatened species because of habitat loss, human conflict, and high prevalence of disease in captivity. An epidemic of feline infectious peritonitis and concern for spread of infectious disease resulted in decreased movement of cheetahs between U.S. zoological facilities for managed captive breeding. Identifying the true feline coronavirus (FCoV) infection status of cheetahs is challenging because of inconsistent correlation between seropositivity and fecal viral shedding. Because the pattern of fecal shedding of FCoV is unknown in cheetahs, this study aimed to assess the frequency of detectable fecal viral shedding in a 30-day period and to determine the most efficient fecal sampling strategy to identify cheetahs shedding FCoV. Fecal samples were collected from 16 cheetahs housed at seven zoological facilities for 30 to 46 consecutive days; the samples were evaluated for the presence of FCoV by reverse transcription-nested polymerase chain reaction (RT-nPCR). Forty-four percent (7/16) of cheetahs had detectable FCoV in feces, and the proportion of positive samples for individual animals ranged from 13 to 93%. Cheetahs shed virus persistently, intermittently, or rarely over 30-46 days. Fecal RT-nPCR results were used to calculate the probability of correctly identifying a cheetah known to shed virus given multiple hypothetical fecal collection schedules. The most efficient hypothetical fecal sample collection schedule was evaluation of five individual consecutive fecal samples, resulting in a 90% probability of identifying a known shedder. Demographic and management risk factors were not significantly associated (P cheetahs shed virus intermittently to rarely, fecal sampling schedules meant to identify all known shedders would be impractical with current tests and eradication of virus from the population unreasonable. Managing the captive population as endemically infected with FCoV may be a more feasible approach.

  2. Water Orientation at Ceramide/Water Interfaces Studied by Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy and Molecular Dynamics Simulation

    KAUST Repository

    Adhikari, Aniruddha

    2016-10-10

    Lipid/water interaction is essential for many biological processes. The water structure at the nonionic lipid interface remains little known, and there is no scope of a priori prediction of water orientation at nonionic interfaces, either. Here, we report our study combining advanced nonlinear spectroscopy and molecular dynamics simulation on the water orientation at the ceramide/water interface. We measured χ spectrum in the OH stretch region of ceramide/isotopically diluted water interface using heterodyne-detected vibrational sum-frequency generation spectroscopy and found that the interfacial water prefers an overall hydrogen-up orientation. Molecular dynamics simulation indicates that this preferred hydrogen-up orientation of water is determined by a delicate balance between hydrogen-up and hydrogen-down orientation induced by lipid-water and intralipid hydrogen bonds. This mechanism also suggests that water orientation at neutral lipid interfaces depends highly on the chemical structure of the lipid headgroup, in contrast to the charged lipid interfaces where the net water orientation is determined solely by the charge of the lipid headgroup.

  3. Epileptic Seizure Detection based on Wavelet Transform Statistics Map and EMD Method for Hilbert-Huang Spectral Analyzing in Gamma Frequency Band of EEG Signals

    Directory of Open Access Journals (Sweden)

    Morteza Behnam

    2015-08-01

    Full Text Available Seizure detection using brain signal (EEG analysis is the important clinical methods in drug therapy and the decisions before brain surgery. In this paper, after signal conditioning using suitable filtering, the Gamma frequency band has been extracted and the other brain rhythms, ambient noises and the other bio-signal are canceled. Then, the wavelet transform of brain signal and the map of wavelet transform in multi levels are computed. By dividing the color map to different epochs, the histogram of each sub-image is obtained and the statistics of it based on statistical momentums and Negentropy values are calculated. Statistical feature vector using Principle Component Analysis (PCA is reduced to one dimension. By EMD algorithm and sifting procedure for analyzing the data by Intrinsic Mode Function (IMF and computing the residues of brain signal using spectrum of Hilbert transform and Hilbert – Huang spectrum forming, one spatial feature based on the Euclidian distance for signal classification is obtained. By K-Nearest Neighbor (KNN classifier and by considering the optimal neighbor parameter, EEG signals are classified in two classes, seizure and non-seizure signal, with the rate of accuracy 76.54% and with variance of error 0.3685 in the different tests.

  4. Extraction and Refinement Strategy for Detection of Autism in 18-Month-Olds: A Guarantee of Higher Sensitivity and Specificity in the Process of Mass Screening

    Science.gov (United States)

    Honda, Hideo; Shimizu, Yasuo; Nitto, Yukari; Imai, Miho; Ozawa, Takeshi; Iwasa, Mitsuaki; Shiga, Keiko; Hira, Tomoko

    2009-01-01

    Background: For early detection of autism, it is difficult to maintain an efficient level of sensitivity and specificity based on observational data from a single screening. The Extraction and Refinement (E&R) Strategy utilizes a public children's health surveillance program to produce maximum efficacy in early detection of autism. In the…

  5. Analysis on frequency response of trans-impedance amplifier (TIA) for signal-to-noise ratio (SNR) enhancement in optical signal detection system using lock-in amplifier (LIA)

    Science.gov (United States)

    Kim, Ji-Hoon; Jeon, Su-Jin; Ji, Myung-Gi; Park, Jun-Hee; Choi, Young-Wan

    2017-02-01

    Lock-in amplifier (LIA) has been widely used in optical signal detection systems because it can measure small signal under high noise level. Generally, The LIA used in optical signal detection system is composed of transimpedance amplifier (TIA), phase sensitive detector (PSD) and low pass filter (LPF). But commercial LIA using LPF is affected by flicker noise. To avoid flicker noise, there is 2ω detection LIA using BPF. To improve the dynamic reserve (DR) of the 2ω LIA, the signal to noise ratio (SNR) of the TIA should be improved. According to the analysis of frequency response of the TIA, the noise gain can be minimized by proper choices of input capacitor (Ci) and feed-back network in the TIA in a specific frequency range. In this work, we have studied how the SNR of the TIA can be improved by a proper choice of frequency range. We have analyzed the way to control this frequency range through the change of passive component in the TIA. The result shows that the variance of the passive component in the TIA can change the specific frequency range where the noise gain is minimized in the uniform gain region of the TIA.

  6. Remote life-detection criteria, habitable zone boundaries, and the frequency of Earth-like planets around M and late K stars.

    Science.gov (United States)

    Kasting, James F; Kopparapu, Ravikumar; Ramirez, Ramses M; Harman, Chester E

    2014-09-02

    The habitable zone (HZ) around a star is typically defined as the region where a rocky planet can maintain liquid water on its surface. That definition is appropriate, because this allows for the possibility that carbon-based, photosynthetic life exists on the planet in sufficient abundance to modify the planet's atmosphere in a way that might be remotely detected. Exactly what conditions are needed, however, to maintain liquid water remains a topic for debate. In the past, modelers have restricted themselves to water-rich planets with CO2 and H2O as the only important greenhouse gases. More recently, some researchers have suggested broadening the definition to include arid, "Dune" planets on the inner edge and planets with captured H2 atmospheres on the outer edge, thereby greatly increasing the HZ width. Such planets could exist, but we demonstrate that an inner edge limit of 0.59 AU or less is physically unrealistic. We further argue that conservative HZ definitions should be used for designing future space-based telescopes, but that optimistic definitions may be useful in interpreting the data from such missions. In terms of effective solar flux, S(eff), the recently recalculated HZ boundaries are: recent Venus--1.78; runaway greenhouse--1.04; moist greenhouse--1.01; maximum greenhouse--0.35; and early Mars--0.32. Based on a combination of different HZ definitions, the frequency of potentially Earth-like planets around late K and M stars observed by Kepler is in the range of 0.4-0.5.

  7. Higher Education

    African Journals Online (AJOL)

    Kunle Amuwo: Higher Education Transformation: A Paradigm Shilt in South Africa? ... ty of such skills, especially at the middle management levels within the higher ... istics and virtues of differentiation and diversity. .... may be forced to close shop for lack of capacity to attract ..... necessarily lead to racial and gender equity,.

  8. CpG Oligonucleotide and Interleukin 2 stimulation enables higher cytogenetic abnormality detection rates than 12-o-tetradecanolyphorbol-13-acetate in Asian patients with B-cell chronic lymphocytic leukemia (B-CLL).

    Science.gov (United States)

    Liaw, Fiona Pui San; Lau, Lai Ching; Lim, Alvin Soon Tiong; Lim, Tse Hui; Lee, Geok Yee; Tien, Sim Leng

    2014-12-01

    The present study was designed to compare abnormality detection rates using DSP30 + IL2 and 12-O-Tetradecanoylphorbol-13-acetate (TPA) in Asian patients with B-CLL. Hematological specimens from 47 patients (29 newly diagnosed, 18 relapsed) were established as 72 h-DSP30 + IL2 and TPA cultures. Standard methods were employed to identify clonal aberrations by conventional cytogenetics (CC). The B-CLL fluorescence in situ hybridization (FISH) panel comprised ATM, CEP12, D13S25, and TP53 probes. DSP30 + IL2 cultures had a higher chromosomal abnormality detection rate (67 %) compared to TPA (44 %, p 0.05). Thirteen cases with abnormalities were found exclusively in DSP30 + IL2 cultures compared to one found solely in TPA cultures. DSP30 + IL2 cultures were comparable to the FISH panel in detecting 11q-, +12 and 17p- but not 13q-. It also has a predilection for 11q- bearing leukemic cells compared to TPA. FISH had a higher abnormality detection rate (84.1 %) compared to CC (66.0 %) with borderline significance (p = 0.051), albeit limited by its coverage. In conclusion, DSP30 + IL2 showed a higher abnormality detection rate. However, FISH is indispensable to circumvent low mitotic indices and detect subtle abnormalities.

  9. Frequency Hopping Transceiver Multiplexer

    Science.gov (United States)

    1983-03-01

    ATC 17 ULR IHQ OCLI CPCTR ULTRA HIGH "OQS" UP TO 4X HIGHER THAN BEST INDUS- TRY STANDARD (ATC 100). MICROWAVE POWER, CURRENT. AND 0 RATINGS5...Q"W were assigned to element (FigC-2); which will be modelled into the transformer previously ment td . The center frequencies, "Q", frequency range...of the TD 1288 system. Temperature stability, change with time or storage. Flexure Frequency, or non-linear change over bandwidth. * Humidity

  10. Higher Education

    Science.gov (United States)

    & Development (LDRD) National Security Education Center (NSEC) Office of Science Programs Richard P Databases National Security Education Center (NSEC) Center for Nonlinear Studies Engineering Institute Scholarships STEM Education Programs Teachers (K-12) Students (K-12) Higher Education Regional Education

  11. Comparison of frequency difference reconstruction algorithms for the detection of acute stroke using EIT in a realistic head-shaped tank

    International Nuclear Information System (INIS)

    Packham, B; Koo, H; Romsauerova, A; Holder, D S; Ahn, S; Jun, S C; McEwan, A

    2012-01-01

    Imaging of acute stroke might be possible using multi-frequency electrical impedance tomography (MFEIT) but requires absolute or frequency difference imaging. Simple linear frequency difference reconstruction has been shown to be ineffective in imaging with a frequency-dependant background conductivity; this has been overcome with a weighted frequency difference approach with correction for the background but this has only been validated for a cylindrical and hemispherical tank. The feasibility of MFEIT for imaging of acute stroke in a realistic head geometry was examined by imaging a potato perturbation against a saline background and a carrot-saline frequency-dependant background conductivity, in a head-shaped tank with the UCLH Mk2.5 MFEIT system. Reconstruction was performed with time difference (TD), frequency difference (FD), FD adjacent (FDA), weighted FD (WFD) and weighted FDA (WFDA) linear algorithms. The perturbation in reconstructed images corresponded to the true position to <9.5% of image diameter with an image SNR of >5.4 for all algorithms in saline but only for TD, WFDA and WFD in the carrot-saline background. No reliable imaging was possible with FD and FDA. This indicates that the WFD approach is also effective for a realistic head geometry and supports its use for human imaging in the future. (paper)

  12. Comparison of a sentinel lymph node mapping algorithm and comprehensive lymphadenectomy in the detection of stage IIIC endometrial carcinoma at higher risk for nodal disease.

    Science.gov (United States)

    Ducie, Jennifer A; Eriksson, Ane Gerda Zahl; Ali, Narisha; McGree, Michaela E; Weaver, Amy L; Bogani, Giorgio; Cliby, William A; Dowdy, Sean C; Bakkum-Gamez, Jamie N; Soslow, Robert A; Keeney, Gary L; Abu-Rustum, Nadeem R; Mariani, Andrea; Leitao, Mario M

    2017-12-01

    To determine if a sentinel lymph node (SLN) mapping algorithm will detect metastatic nodal disease in patients with intermediate-/high-risk endometrial carcinoma. Patients were identified and surgically staged at two collaborating institutions. The historical cohort (2004-2008) at one institution included patients undergoing complete pelvic and paraaortic lymphadenectomy to the renal veins (LND cohort). At the second institution an SLN mapping algorithm, including pathologic ultra-staging, was performed (2006-2013) (SLN cohort). Intermediate-risk was defined as endometrioid histology (any grade), ≥50% myometrial invasion; high-risk as serous or clear cell histology (any myometrial invasion). Patients with gross peritoneal disease were excluded. Isolated tumor cells, micro-metastases, and macro-metastases were considered node-positive. We identified 210 patients in the LND cohort, 202 in the SLN cohort. Nodal assessment was performed for most patients. In the intermediate-risk group, stage IIIC disease was diagnosed in 30/107 (28.0%) (LND), 29/82 (35.4%) (SLN) (P=0.28). In the high-risk group, stage IIIC disease was diagnosed in 20/103 (19.4%) (LND), 26 (21.7%) (SLN) (P=0.68). Paraaortic lymph node (LN) assessment was performed significantly more often in intermediate-/high-risk groups in the LND cohort (P<0.001). In the intermediate-risk group, paraaortic LN metastases were detected in 20/96 (20.8%) (LND) vs. 3/28 (10.7%) (SLN) (P=0.23). In the high-risk group, paraaortic LN metastases were detected in 13/82 (15.9%) (LND) and 10/56 (17.9%) (SLN) (%, P=0.76). SLN mapping algorithm provides similar detection rates of stage IIIC endometrial cancer. The SLN algorithm does not compromise overall detection compared to standard LND. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Frequency tripling with multimode-lasers

    International Nuclear Information System (INIS)

    Langer, H.; Roehr, H.; Wrobel, W.G.

    1978-10-01

    The presence of different modes with random phases in a laser beam leads to fluctuations in nonlinear optical interactions. This paper describes the influence of the linewidth of a dye laser on the generation of intensive Lyman-alpha radiation by frequency tripling. Using this Lyman-alpha source for resonance scattering on strongly doppler-broadened lines in fusion plasmas the detection limit of neutral hydrogen is nearly two orders higher with the multimode than the singlemode dye laser. (orig.) [de

  14. Analysis of algorithms for detection of resonance frequencies in vibration measurements on super heater tubes; Analys av algoritmer foer detektering av resonansfrekvenser i vibrationsmaetningar paa oeverhettartuber

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Daniel

    2010-07-01

    Combustion of fuel in thermal power plants emits particles which creates coatings on the super heater tubes. The coatings isolate the tubes and impairs the efficiency of the heat transfer. Cleaning the tubes occurs while the power plant is running but without any knowledge of the actual coating. A change in frequency corresponds to a change in mass of the coatings. This thesis has been focusing in estimating resonance frequencies in vibration measurements made by strain gauges on the tubes. To improve the estimations a target tracking algorithm had been added. The results indicates that it is possible to estimate the resonance frequencies but the algorithms need to be verified on more signals.

  15. The attendance of women in mammographic early detection programme and the results of the observation of the breast glands condition. 1. The attendance of higher schools female employees in mammography examination

    International Nuclear Information System (INIS)

    Romejko, M.; Kleszczewska, J.; Liszek, A.; Tarlowska, L.; Wronkowski, Z.

    1993-01-01

    The aim of the first part of this work is to assess the attendance in the early detection (mammography) in female employees of Warsaw-based higher schools aged 40-69. During the 4.5 year period (1985-1989) 1325 female employees of higher schools (23.5% of the schools' total employment) turned up to the Female Cancer Prevention Center of The Higher Schools' Medical Center (ZOZ) in Warsaw. Observation of this group continued until June 30, 1992. Majority of the women (56.5%) showed up only once, 21.7% came twice, and 21.8% at least three times. Out of the 1021 women (77% of all the examined female employees) who showed no symptoms in the first test, only 37% came again for the second checkup. Out of the 305 women who had changes detected in their X-ray images, 66% turned up for the second test. 23 women (1.7%) had suspicious mammography results or typical cancer symptoms in the first test. The present work shows that the reason of the insufficient attendance of higher schools' female employees in early detection programs need to be investigated and that a more efficient early detection system must be developed. (author)

  16. Genotyping of friesian horses to detect a hydrocephalus-associated c.1423C>T mutation in B3GALNT2 using PCR-RFLP and PCR-PIRA methods: Frequency in stallion horses in México.

    Science.gov (United States)

    Ayala-Valdovinos, Miguel Angel; Galindo-García, Jorge; Sánchez-Chiprés, David; Duifhuis-Rivera, Theodor

    2017-04-01

    Hydrocephalus in Friesian horses is an autosomal recessive hereditary disease that can result in an abortion, a stillbirth, or euthanization of a newborn foal. Here, the hydrocephalus-associated c.1423C > T mutation in B3GALNT2 gene was detected with PCR-RFLP and PCR-PIRA methods for horse genotyping. A preliminary genotyping survey was performed on 83 randomly selected Friesian stallion horses to determine the current allele frequency in Mexico. The frequency of the mutant T allele was 9.6%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Additional lesions detected in therapeutic scans with 177Lu-DOTATATE reflect higher affinity of 177Lu-DOTATATE for somatostatin receptors.

    Science.gov (United States)

    Mirzaei, Siroos; Bastati, Brigitte; Lipp, Rainer W; Knoll, Peter; Zojer, Niklas; Ludwig, Heinz

    2011-01-01

    Peptide receptor-targeted radionuclide therapy (PRRT) of somatostatin receptor (SR)-expressing neuroendocrine tumors (NETs) has become an established therapeutic option in patients with advanced NETs. The aim of this study was to compare the lesion detection rate of (99m)Tc-EDDA/HYNIC-TOC, a newly developed tracer for NET imaging, with (177)Lu-DOTATATE used for PRRT. 8 patients (4 women, 4 men, age range 46-76 years) with histologically proven NETs, who showed high SR loads by (99m)Tc-EDDA/HYNIC-TOC scintigraphy, were treated with (177)Lu-DOTATATE. After treatment, all patients were subjected to whole-body scintigraphy with additional low-dose single-photon emission computed tomography (SPECT-CT) of the chest and abdomen. All patients demonstrated (177)Lu-DOTATATE accumulation in all lesions previously detected by (99m)Tc- EDDA/HYNIC-TOC scintigraphy. Three patients showed additional lesions in the liver and lungs. SPECT-CT after (177)Lu-DOTATATE therapy may be helpful in detecting additional lesions not seen using (99m)Tc-EDDA/HYNIC-TOC. This could reflect the broader affinity of (177)Lu-DOTATATE for SRs compared with (99m)Tc-EDDA/HYNIC-TOC. Copyright © 2011 S. Karger AG, Basel.

  18. Interphase fluorescence in situ hybridization analysis detects a much higher rate of thyroid tumors with clonal cytogenetic deviations of the main cytogenetic subgroups than conventional cytogenetics.

    Science.gov (United States)

    Drieschner, Norbert; Rippe, Volkhard; Laabs, Anne; Dittberner, Lea; Nimzyk, Rolf; Junker, Klaus; Rommel, Birgit; Kiefer, Yvonne; Belge, Gazanfer; Bullerdiek, Jörn; Sendt, Wolfgang

    2011-07-01

    In benign thyroid lesions, three main cytogenetic subgroups, characterized by trisomy 7 or structural aberrations involving either chromosomal region 19q13.4 or 2p21, can be distinguished by conventional cytogenetics (CC). As a rule, these aberrations seem to be mutually exclusive. Interphase fluorescence in situ hybridization (I-FISH) analysis on benign as well as malignant thyroid neoplasias has been performed in the past, but rarely in combination with CC. In the present paper, we have analyzed 161 benign thyroid lesions both with CC and I-FISH on touch preparations by using a multi-target, triple-color FISH assay as well as dual-color break-apart probes for detection of the main cytogenetic subgroups. Within the samples, I-FISH detected tumors belonging to either of the subgroups more frequently than CC (23 vs. 11.4%), either due to small subpopulations of aberrant cells or to cryptic chromosomal rearrangements (three cases). Thus, I-FISH seems to be more sensitive than CC, particularly in the detection of subpopulations of cells harboring cytogenetic aberrations that may be overlooked by CC. In summary, I-FISH on touch preparations of benign thyroid lesions seems to be a favorable method for cytogenetic subtyping of thyroid lesions. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Technical Note: Higher-order statistical moments and a procedure that detects potentially anomalous years as two alternative methods describing alterations in continuous environmental data

    Science.gov (United States)

    I. Arismendi; S. L. Johnson; J. B. Dunham

    2015-01-01

    Statistics of central tendency and dispersion may not capture relevant or desired characteristics of the distribution of continuous phenomena and, thus, they may not adequately describe temporal patterns of change. Here, we present two methodological approaches that can help to identify temporal changes in environmental regimes. First, we use higher-order statistical...

  20. Higher Education.

    Science.gov (United States)

    Hendrickson, Robert M.

    This chapter reports 1982 cases involving aspects of higher education. Interesting cases noted dealt with the federal government's authority to regulate state employees' retirement and raised the questions of whether Title IX covers employment, whether financial aid makes a college a program under Title IX, and whether sex segregated mortality…

  1. Modulation frequency as a cue for auditory speed perception.

    Science.gov (United States)

    Senna, Irene; Parise, Cesare V; Ernst, Marc O

    2017-07-12

    Unlike vision, the mechanisms underlying auditory motion perception are poorly understood. Here we describe an auditory motion illusion revealing a novel cue to auditory speed perception: the temporal frequency of amplitude modulation (AM-frequency), typical for rattling sounds. Naturally, corrugated objects sliding across each other generate rattling sounds whose AM-frequency tends to directly correlate with speed. We found that AM-frequency modulates auditory speed perception in a highly systematic fashion: moving sounds with higher AM-frequency are perceived as moving faster than sounds with lower AM-frequency. Even more interestingly, sounds with higher AM-frequency also induce stronger motion aftereffects. This reveals the existence of specialized neural mechanisms for auditory motion perception, which are sensitive to AM-frequency. Thus, in spatial hearing, the brain successfully capitalizes on the AM-frequency of rattling sounds to estimate the speed of moving objects. This tightly parallels previous findings in motion vision, where spatio-temporal frequency of moving displays systematically affects both speed perception and the magnitude of the motion aftereffects. Such an analogy with vision suggests that motion detection may rely on canonical computations, with similar neural mechanisms shared across the different modalities. © 2017 The Author(s).

  2. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  3. Unlocking higher harmonics in atomic force microscopy with gentle interactions.

    Science.gov (United States)

    Santos, Sergio; Barcons, Victor; Font, Josep; Verdaguer, Albert

    2014-01-01

    In dynamic atomic force microscopy, nanoscale properties are encoded in the higher harmonics. Nevertheless, when gentle interactions and minimal invasiveness are required, these harmonics are typically undetectable. Here, we propose to externally drive an arbitrary number of exact higher harmonics above the noise level. In this way, multiple contrast channels that are sensitive to compositional variations are made accessible. Numerical integration of the equation of motion shows that the external introduction of exact harmonic frequencies does not compromise the fundamental frequency. Thermal fluctuations are also considered within the detection bandwidth of interest and discussed in terms of higher-harmonic phase contrast in the presence and absence of an external excitation of higher harmonics. Higher harmonic phase shifts further provide the means to directly decouple the true topography from that induced by compositional heterogeneity.

  4. Detection and Analytical Capabilities for Trace Level of Carbon in High-Purity Metals by Laser-Induced Breakdown Spectroscopy with a Frequency Quintupled 213 nm Nd:YAG Laser

    Directory of Open Access Journals (Sweden)

    Masaki Ohata

    2017-01-01

    Full Text Available The laser-induced breakdown spectroscopy (LIBS with a frequency quintupled 213 nm Nd:YAG laser was examined to the analysis of trace level of carbon (C in high-purity metals and its detection and analytical capabilities were evaluated. Though C signal in a wavelength of 247.9 nm, which showed the highest sensitivity of C, could be obtained from Cd, Ti, and Zn ca. 7000 mg kg−1 C in Fe could not be detected due to the interferences from a lot of Fe spectra. Alternative C signal in a wavelength of 193.1 nm could not be also detected from Fe due to the insufficient laser output energy of the frequency quintupled 213 nm Nd:YAG laser. The depth analysis of C by LIBS was also demonstrated and the C in Cd and Zn was found to be contaminated in only surface area whereas the C in Ti was distributed in bulk. From these results, the frequency quintupled 213 nm Nd:YAG laser, which was adopted widely as a commercial laser ablation (LA system coupled with inductively coupled plasma mass spectrometry (ICPMS for trace element analysis in solid materials, could be used for C analysis to achieve simultaneous measurements for both C and trace elements in metals by LIBS and LA-ICPMS, respectively.

  5. Detection Of Cracks In Composite Materials Using Hybrid Non-Destructive Testing Method Based On Vibro-Thermography And Time-Frequency Analysis Of Ultrasonic Excitation Signal

    Directory of Open Access Journals (Sweden)

    Prokopowicz Wojciech

    2015-09-01

    Full Text Available The theme of the publication is to determine the possibility of diagnosing damage in composite materials using vibrio-thermography and frequency analysis and time-frequency of excitation signal. In order to verify the proposed method experiments were performed on a sample of the composite made in the technology of pressing prepregs. Analysis of the recorded signals and the thermograms were performed in MatLab environment. Hybrid non-destructive testing method based on thermogram and appropriate signal processing algorithm clearly showed damage in the sample composite material.

  6. The detection of structural defects in metallic materials and components using a non-destructive multi-frequency eddy current method

    International Nuclear Information System (INIS)

    Becker, R.

    1980-01-01

    Application of the multi-frequency method in eddy current testing is shown to be usefull for many important and complex problems in the field of non-destructive testing, which cannot be solved by the single frequency method because of principle reasons. Also in the presence of several perturbing signals the method can be applied successfully, thus very often difference coils can be replaced by absolute coils. Introducing the algorithm of multidimensional direction selection, the calibration of the test system is simpler, allowing automization of the calibration process. In addition, the test signals related with the defect parameters can be evaluated in an objective way. (orig./RW) [de

  7. A comparative analysis of molecular genetic and conventional cytogenetic detection of diagnostically important translocations in more than 400 cases of acute leukemia, highlighting the frequency of false-negative conventional cytogenetics.

    Science.gov (United States)

    King, Rebecca L; Naghashpour, Mojdeh; Watt, Christopher D; Morrissette, Jennifer J D; Bagg, Adam

    2011-06-01

    In this study, we correlated the results of concurrent molecular and cytogenetic detection of entity-defining translocations in adults with acute leukemia to determine the frequency of cryptic translocations missed by conventional cytogenetics (CC) and of recurrent, prognostically relevant translocations not detectable by multiplex reverse transcriptase-polymerase chain reaction (MRP). During a 5.5-year period, 442 diagnostic acute leukemia specimens were submitted for MRP-based detection of 7 common recurrent translocations: t(8;21), t(15;17), inv(16), t(9;22), t(12;21), t(4;11), and t(1;19), with a detection rate of 15.2% (67/442). CC was performed in 330 (74.7%) of 442 cases. In 7 of these 330 cases, CC missed the translocation detected by MRP. In 50 additional cases, CC revealed 1 of the MRP-detectable translocations (all were also MRP positive), yielding a false-negative rate of 12% (7/57) for the CC assay. The remaining 140 of 190 cases with clonal cytogenetic changes harbored abnormalities that were not targeted by the MRP assay, including 8 that define specific acute myeloid leukemia entities. This study revealed the frequent occurrence of false-negative, entity-defining CC analysis and highlighted the complementary nature of MRP and CC approaches in detecting genetic abnormalities in acute leukemia.

  8. Frequency Synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus M.W.; Breems, Lucien J.; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  9. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2010-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  10. Sound detection by the longfin squid (em>Loligo pealeiiem>) studied with auditory evoked potentials: sensitivity to low-frequency particle motion and not pressure

    DEFF Research Database (Denmark)

    Mooney, T. Aran; Hanlon, Roger T; Christensen-Dalsgaard, Jakob

    2010-01-01

    of two wave types: (1) rapid stimulus-following waves, and (2) slower, high-amplitude waves, similar to some fish AEPs. Responses were obtained between 30 and 500 Hz with lowest thresholds between 100 and 200 Hz. At the best frequencies, AEP amplitudes were often >20 µV. Evoked potentials were...

  11. Two-photon excited fluorescence from higher electronic states of chlorophylls in photosynthetic antenna complexes a new approach to detect strong excitonic chlorophyll a/b coupling

    CERN Document Server

    Leupold, D; Ehlert, J; Irrgang, K D; Renger, G; Lokstein, H

    2002-01-01

    Stepwise two-photon excitation of chlorophyll a and b in the higher plant main light-harvesting complex (LHC II) and the minor complex CP29 (as well as in organic solution) with 100-fs pulses in the Q/sub y/ region results in a weak blue fluorescence. The dependence of the spectral shape of the blue fluorescence on excitation wavelength offers a new approach to elucidate the long-standing problem of the origin of spectral "chlorophyll forms" in pigment-protein complexes, in particular the characterization of chlorophyll a/b-heterodimers. As a first result we present evidence for the existence of strong chlorophyll a/b-interactions (excitonically coupled transitions at 650 and 680 nm) in LHC II at ambient temperature. In comparison with LHC II, the experiments with CP29 provide further evidence that the lowest energy chlorophyll a transition (at ~680 nm) is not excitonically coupled to chlorophyll b. (22 refs).

  12. Statistical Signal Processing by Using the Higher-Order Correlation between Sound and Vibration and Its Application to Fault Detection of Rotational Machine

    Directory of Open Access Journals (Sweden)

    Hisako Masuike

    2008-01-01

    Full Text Available In this study, a stochastic diagnosis method based on the changing information of not only a linear correlation but also a higher-order nonlinear correlation is proposed in a form suitable for online signal processing in time domain by using a personal computer, especially in order to find minutely the mutual relationship between sound and vibration emitted from rotational machines. More specifically, a conditional probability hierarchically reflecting various types of correlation information is theoretically derived by introducing an expression on the multidimensional probability distribution in orthogonal expansion series form. The effectiveness of the proposed theory is experimentally confirmed by applying it to the observed data emitted from a rotational machine driven by an electric motor.

  13. A Geometry-Based Cycle Slip Detection and Repair Method with Time-Differenced Carrier Phase (TDCP for a Single Frequency Global Position System (GPS + BeiDou Navigation Satellite System (BDS Receiver

    Directory of Open Access Journals (Sweden)

    Chuang Qian

    2016-12-01

    Full Text Available As the field of high-precision applications based on carriers continues to expand, the development of low-cost, small, modular receivers and their application in diverse scenarios and situations with complex data quality has increased the requirements of carrier-phase data preprocessing. A new geometry-based cycle slip detection and repair method based on Global Position System (GPS + BeiDou Navigation Satellite System (BDS is proposed. The method uses a Time-differenced Carrier Phase (TDCP model, which eliminates the Inner-System Bias (ISB between GPS and BDS, and it is conducive to the effective combination of GPS and BDS. It avoids the interference of the noise of the pseudo-range with cycle slip detection, while the cycle slips are preserved as integers. This method does not limit the receiver frequency number, and it is applicable to single-frequency data. The process is divided into two steps to detect and repair cycle slip. The first step is cycle slip detection, using the Improved Local Analysis Method (ILAM to find satellites that have cycle slips; The second step is to repair the cycle slips, including estimating the float solution of changes in ambiguities at the satellites that have cycle slips with the least squares method and the integer solution of the cycle slips by rounding. In the process of rounding, in addition to the success probability, a decimal test is carried out to validate the result. Finally, experiments with filed test data are carried out to prove the effectiveness of this method. The results show that the detectable cycle slips number with GPS + BDS is much greater than that with GPS. The method can also detect the non-integer outliers while fixing the cycle slip. The maximum decimal bias in repair is less than that with GPS. It implies that this method takes full advantages of multi-system.

  14. Electric current - frequency converter

    International Nuclear Information System (INIS)

    Kumahara, Tadashi; Kinbana, Setsuro.

    1967-01-01

    Herein disclosed is an improved simple electric current-frequency converter, the input current and output frequency linearity of which is widened to a range of four to five figures while compensating, for temperature. The converter may be used for computor processing and for telemetering the output signals from a nuclear reactor. The converter is an astable multivibrator which includes charging circuits comprising emitter-voltage compensated NPN transistors, a charged voltage detecting circuit of temperature compensated field effect transistors, and a transistor switching circuit for generating switching pulses independent of temperature. The converter exhibited a 0.7% frequency change within a range of 5 - 45 0 C and less than a 0.1% frequency drift after six hours of operation when the input current was maintained constant. (Yamaguchi, T.)

  15. VirVarSeq: a low-frequency virus variant detection pipeline for Illumina sequencing using adaptive base-calling accuracy filtering.

    Science.gov (United States)

    Verbist, Bie M P; Thys, Kim; Reumers, Joke; Wetzels, Yves; Van der Borght, Koen; Talloen, Willem; Aerssens, Jeroen; Clement, Lieven; Thas, Olivier

    2015-01-01

    In virology, massively parallel sequencing (MPS) opens many opportunities for studying viral quasi-species, e.g. in HIV-1- and HCV-infected patients. This is essential for understanding pathways to resistance, which can substantially improve treatment. Although MPS platforms allow in-depth characterization of sequence variation, their measurements still involve substantial technical noise. For Illumina sequencing, single base substitutions are the main error source and impede powerful assessment of low-frequency mutations. Fortunately, base calls are complemented with quality scores (Qs) that are useful for differentiating errors from the real low-frequency mutations. A variant calling tool, Q-cpileup, is proposed, which exploits the Qs of nucleotides in a filtering strategy to increase specificity. The tool is imbedded in an open-source pipeline, VirVarSeq, which allows variant calling starting from fastq files. Using both plasmid mixtures and clinical samples, we show that Q-cpileup is able to reduce the number of false-positive findings. The filtering strategy is adaptive and provides an optimized threshold for individual samples in each sequencing run. Additionally, linkage information is kept between single-nucleotide polymorphisms as variants are called at the codon level. This enables virologists to have an immediate biological interpretation of the reported variants with respect to their antiviral drug responses. A comparison with existing SNP caller tools reveals that calling variants at the codon level with Q-cpileup results in an outstanding sensitivity while maintaining a good specificity for variants with frequencies down to 0.5%. The VirVarSeq is available, together with a user's guide and test data, at sourceforge: http://sourceforge.net/projects/virtools/?source=directory. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. Application of a novel measure of EEG non-stationarity as 'Shannon- entropy of the peak frequency shifting' for detecting residual abnormalities in concussed individuals.

    Science.gov (United States)

    Cao, Cheng; Slobounov, Semyon

    2011-07-01

    The aim of this report was to propose a novel measure of non-stationarity of EEG signals, named Shannon- entropy of the peak frequency shifting (SEPFS). The feasibility of this method was documented comparing this measure with traditional time domain assessment of non-stationarity and its application to EEG data sets obtained from student-athletes before and after suffering a single episode of mild traumatic brain injury (mTBI) with age-matched normal controls. Instead of assessing the power density distribution on the time-frequency plane, like previously proposed measures of signal non-stationarity, this new measure is based on the shift of the dominant frequency of the EEG signal over time. We applied SEPFS measure to assess the properties of EEG non-stationarity in subjects before and shortly after they suffered mTBI. Student-athletes at high risk for mTBI (n=265) were tested prior to concussive episodes as a baseline. From this subject pool, 30 athletes who suffered from mTBI were retested on day 30 post-injury. Additional subjects pool (student-athletes without history of concussion, n=30) were recruited and test-re-tested within the same 30 day interval. Thirty-two channels EEG signals were acquired in sitting eyes closed condition. The results showed that the SEPFS values significantly decreased in subjects suffering from mTBI. Specifically, reduced EEG non-stationarity was observed in occipital, temporal and central brain areas, indicating the possibility of residual brain dysfunctions in concussed individuals. A similar but less statistically significant trend was observed using traditional time domain analysis of EEG non-stationarity. The proposed measure has at least two merits of interest: (1) it is less affected by the limited resolution of time-frequency representation of the EEG signal; (2) it takes into account the neural characteristics of the EEG signal that have not been considered in previously proposed measures of non-stationarity. This new

  17. Frequency spirals

    International Nuclear Information System (INIS)

    Ottino-Löffler, Bertrand; Strogatz, Steven H.

    2016-01-01

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  18. Frequency spirals

    Energy Technology Data Exchange (ETDEWEB)

    Ottino-Löffler, Bertrand; Strogatz, Steven H., E-mail: strogatz@cornell.edu [Center for Applied Mathematics, Cornell University, Ithaca, New York 14853 (United States)

    2016-09-15

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  19. Towards terahertz detection and calibration through spontaneous parametric down-conversion in the terahertz idler-frequency range generated by a 795 nm diode laser system

    Directory of Open Access Journals (Sweden)

    Vladimir V. Kornienko

    2018-05-01

    Full Text Available We study a calibration scheme for terahertz wave nonlinear-optical detectors based on spontaneous parametric down-conversion. Contrary to the usual low wavelength pump in the green, we report here on the observation of spontaneous parametric down-conversion originating from an in-growth poled lithium niobate crystal pumped with a continuous wave 50 mW, 795 nm diode laser system, phase-matched to a terahertz frequency idler wave. Such a system is more compact and allows for longer poling periods as well as lower losses in the crystal. Filtering the pump radiation by a rubidium-87 vapor cell allowed the frequency-angular spectra to be obtained down to ∼0.5 THz or ∼1 nm shift from the pump radiation line. The presence of an amplified spontaneous emission “pedestal” in the diode laser radiation spectrum significantly hampers the observation of spontaneous parametric down-conversion spectra, in contrast to conventional narrowband gas lasers. Benefits of switching to longer pump wavelengths are pointed out, such as collinear optical-terahertz phase-matching in bulk crystals.

  20. The U2 snDNA Is a Useful Marker for B Chromosome Detection and Frequency Estimation in the Grasshopper Abracris flavolineata.

    Science.gov (United States)

    Milani, Diogo; Palacios-Gimenez, Octavio M; Cabral-de-Mello, Diogo C

    2017-01-01

    In this study, we describe a strategy to determine the presence of B chromosomes in the living grasshopper Abracris flavolineata by FISH using U2 snDNA as a probe in interphase hemolymph nuclei. In individuals without B chromosomes, (0B) 2 dot signals were noticed, corresponding to A complement U2 snDNA clusters. In +1B and +2B individuals, 4 or 8 additional signals were noticed, respectively. In all cases, the absence or presence of 1 or 2 B chromosomes correlated in hemolymph and in somatic or germline tissues, validating the efficiency of the marker. Our data suggest that the B chromosome of A. flavolineata is present in all somatic tissues. B-carrying individuals showed the same number of B chromosomes in germ and somatic cells, suggesting that the B is mitotically stable. The marker was used to compare B chromosome frequency in the analyzed population with a sample collected previously, in order to test for B frequency changes and differences of B chromosome prevalence among sexes, but no statistically significant differences were noticed. The identification of living animals harboring B chromosomes will be very useful in future studies of B chromosome transmission, as well as in functional studies involving RNA analysis, thus contributing to the understanding of evolutionary history and the possible role of the B chromosome in A. flavolineata. © 2017 S. Karger AG, Basel.

  1. High-frequency detection of cell activity of Physarum polycephalum by a planar open gate AlGaN/GaN HEMT

    International Nuclear Information System (INIS)

    Witte, Hartmut; Lippelt, Thomas; Warnke, Christian; Dadgar, Armin; Krost, Alois; Hauser, Marcus J B

    2014-01-01

    The dynamics of cells of the slime mould Physarum polycephalum are investigated with a planar AlGaN/GaN high electron mobility transistor (HEMT) without any gate metallization. The source–drain contacts are used in a two-electrode arrangement whereas the free gate surface area is occupied by the Physarum cell. In order to understand the measured signals, basic properties of the interface between the cell and the HEMT surface were analysed by impedance spectroscopy. At high frequencies the interface impedance is governed by the conductance of the cell due to a direct current through the HEMT/cell interface. The locomotive dynamics of Physarum were recorded by the source–drain impedance at 10 kHz in combination with simultaneous video imaging that monitored the degree of occupancy of the HEMT surface by the cell. A precise correlation was found between the impedance and the coverage of the HEMT surface by the cell. It is observed that the entire region between the contacts is sensitive to the cell activity. Well-resolved cellular oscillations were observed for all measured parameters. Their periods corresponded to the typical periods of the intracellular shuttle streaming of protoplasma in Physarum. This demonstrates that high-frequency impedance measurements with AlGaN/GaN HEMT structures are well suited for the analysis of both the static parts of single Physarum cells as well as of their dynamic behaviour, such as their expansion and motility. (paper)

  2. Towards terahertz detection and calibration through spontaneous parametric down-conversion in the terahertz idler-frequency range generated by a 795 nm diode laser system

    Science.gov (United States)

    Kornienko, Vladimir V.; Kitaeva, Galiya Kh.; Sedlmeir, Florian; Leuchs, Gerd; Schwefel, Harald G. L.

    2018-05-01

    We study a calibration scheme for terahertz wave nonlinear-optical detectors based on spontaneous parametric down-conversion. Contrary to the usual low wavelength pump in the green, we report here on the observation of spontaneous parametric down-conversion originating from an in-growth poled lithium niobate crystal pumped with a continuous wave 50 mW, 795 nm diode laser system, phase-matched to a terahertz frequency idler wave. Such a system is more compact and allows for longer poling periods as well as lower losses in the crystal. Filtering the pump radiation by a rubidium-87 vapor cell allowed the frequency-angular spectra to be obtained down to ˜0.5 THz or ˜1 nm shift from the pump radiation line. The presence of an amplified spontaneous emission "pedestal" in the diode laser radiation spectrum significantly hampers the observation of spontaneous parametric down-conversion spectra, in contrast to conventional narrowband gas lasers. Benefits of switching to longer pump wavelengths are pointed out, such as collinear optical-terahertz phase-matching in bulk crystals.

  3. Stable radio frequency dissemination by simple hybrid frequency modulation scheme.

    Science.gov (United States)

    Yu, Longqiang; Wang, Rong; Lu, Lin; Zhu, Yong; Wu, Chuanxin; Zhang, Baofu; Wang, Peizhang

    2014-09-15

    In this Letter, we propose a fiber-based stable radio frequency transfer system by a hybrid frequency modulation scheme. Creatively, two radio frequency signals are combined and simultaneously transferred by only one laser diode. One frequency component is used to detect the phase fluctuation, and the other one is the derivative compensated signal providing a stable frequency for the remote end. A proper ratio of the frequencies of the components is well maintained by parameter m to avoid interference between them. Experimentally, a stable 200 MHz signal is transferred over 100 km optical fiber with the help of a 1 GHz detecting signal, and fractional instability of 2×10(-17) at 10(5) s is achieved.

  4. Frogs Call at a Higher Pitch in Traffic Noise

    Directory of Open Access Journals (Sweden)

    Kirsten M. Parris

    2009-06-01

    Full Text Available Male frogs call to attract females for mating and to defend territories from rival males. Female frogs of some species prefer lower-pitched calls, which indicate larger, more experienced males. Acoustic interference occurs when background noise reduces the active distance or the distance over which an acoustic signal can be detected. Birds are known to call at a higher pitch or frequency in urban noise, decreasing acoustic interference from low-frequency noise. Using Bayesian linear regression, we investigated the effect of traffic noise on the pitch of advertisement calls in two species of frogs, the southern brown tree frog (Litoria ewingii and the common eastern froglet (Crinia signifera. We found evidence that L. ewingii calls at a higher pitch in traffic noise, with an average increase in dominant frequency of 4.1 Hz/dB of traffic noise, and a total effect size of 123 Hz. This frequency shift is smaller than that observed in birds, but is still large enough to be detected by conspecific frogs and confer a significant benefit to the caller. Mathematical modelling predicted a 24% increase in the active distance of a L. ewingii call in traffic noise with a frequency shift of this size. Crinia signifera may also call at a higher pitch in traffic noise, but more data are required to be confident of this effect. Because frog calls are innate rather than learned, the frequency shift demonstrated by L. ewingii may represent an evolutionary adaptation to noisy conditions. The phenomenon of frogs calling at a higher pitch in traffic noise could therefore constitute an intriguing trade-off between audibility and attractiveness to potential mates.

  5. Low frequency radioastronomy

    International Nuclear Information System (INIS)

    Zarka, Philippe; Cecconi, Baptiste; Tagger, Michel; Torchinsky, Steve; Picard, Philippe; Pezzani, Jacques; Cognard, Ismael; Boone, Frederic; Woan, Graham; Weber, Rodolphe; Gousset, Thierry; Lautridou, Pascal; Dallier, Richard

    2011-07-01

    Low frequency radioastronomy deals with the direct detection (below 100 MHz) and heterodyne detection (up to few GHz) of electromagnetic waves (phase and amplitude) followed by a time or spectral analysis. The 30. Goutelas school covered several aspects of radioastronomy involving various aspects of physics: non-thermal phenomena in plasmas and physics of magnetized plasmas, atomic and molecular physics, and particle physics. These proceedings comprise 17 lectures dealing with: 1 - Low-Frequency Radioastronomy Basics (P. Zarka); 2 - Radioastronomy Historical Highlights (S. A. Torchinsky); 3 - Antennas (P. Picard, J. Pezzani); 4 - Receptors (P. Picard, J. Pezzani); 5 - Pulsars chronometry: metrology in radioastronomy (I. Cognard); 6 - Interferometry as imaging technique (F. Boone); 7 - Radio propagation and scintillation (G. Woan); 8 - Square Kilometer Array (S. A. Torchinsky); 9 - Techniques against radio-electrical interferences in low-frequency radioastronomy (R. Weber); 10 - Introduction to poly-phase filtering (R. Weber); 11 - Three decades of Jupiter's radio-emission studies: from the Nancay deca-meter network to LOFAR (P. Zarka); 12 - Atmospheric showers and their radio counterpart (T. Gousset); 13 - From cosmic rays radio-detection to pulse radioastronomy (P. Lautridou, R. Dallier); 14 - The CODALEMA project (R. Dallier, P. Lautridou); 15 - Space-based radio measurements: Gonio-polarimetry (B. Cecconi); 16 - Radio astronomy from space (G. Woan); 17 - LOFAR: the Low Frequency Array and the French FLOW consortium (M. Tagger, P. Zarka)

  6. Detection of the adsorption of water monolayers through the ion oscillation frequency in the magnesium oxide lattice by means of low energy electron diffraction

    Directory of Open Access Journals (Sweden)

    M. Guevara-Bertsch

    2016-03-01

    Full Text Available We investigate the variation of the oscillation frequency of the Mg2+ and O2− ions in the magnesium oxide lattice due to the interactions of the surface with water monolayers by means of Low Energy Electron Diffraction. Our key result is a new technique to determine the adsorbate vibrations produced by the water monolayers on the surface lattice as a consequence of their change in the surface Debye temperature and its chemical shift. The latter was systematically investigated for different annealing times and for a constant external thermal perturbation in the range of 110–300 K in order to accomplish adsorption or desorption of water monolayers in the surface lattice.

  7. Iterative MMSE Detection for MIMO/BLAST DS-CDMA Systems in Frequency Selective Fading Channels - Achieving High Performance in Fully Loaded Systems

    Science.gov (United States)

    Silva, João Carlos; Souto, Nuno; Cercas, Francisco; Dinis, Rui

    A MMSE (Minimum Mean Square Error) DS-CDMA (Direct Sequence-Code Division Multiple Access) receiver coupled with a low-complexity iterative interference suppression algorithm was devised for a MIMO/BLAST (Multiple Input, Multiple Output / Bell Laboratories Layered Space Time) system in order to improve system performance, considering frequency selective fading channels. The scheme is compared against the simple MMSE receiver, for both QPSK and 16QAM modulations, under SISO (Single Input, Single Output) and MIMO systems, the latter with 2Tx by 2Rx and 4Tx by 4Rx (MIMO order 2 and 4 respectively) antennas. To assess its performance in an existing system, the uncoded UMTS HSDPA (High Speed Downlink Packet Access) standard was considered.

  8. Detection of the adsorption of water monolayers through the ion oscillation frequency in the magnesium oxide lattice by means of low energy electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Guevara-Bertsch, M.; Avendaño, E. [Escuela de Física, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Ramírez-Hidalgo, G. [Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Sección de Física Teórica, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Chavarría-Sibaja, A.; Araya-Pochet, J. A. [Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Herrera-Sancho, O. A., E-mail: oscar-andrey.herrera@uibk.ac.at [Escuela de Física, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstr. 21a, 6020 Innsbruck (Austria)

    2016-03-15

    We investigate the variation of the oscillation frequency of the Mg{sup 2+} and O{sup 2−} ions in the magnesium oxide lattice due to the interactions of the surface with water monolayers by means of Low Energy Electron Diffraction. Our key result is a new technique to determine the adsorbate vibrations produced by the water monolayers on the surface lattice as a consequence of their change in the surface Debye temperature and its chemical shift. The latter was systematically investigated for different annealing times and for a constant external thermal perturbation in the range of 110–300 K in order to accomplish adsorption or desorption of water monolayers in the surface lattice.

  9. Islanding detection technique using wavelet energy in grid-connected PV system

    Science.gov (United States)

    Kim, Il Song

    2016-08-01

    This paper proposes a new islanding detection method using wavelet energy in a grid-connected photovoltaic system. The method detects spectral changes in the higher-frequency components of the point of common coupling voltage and obtains wavelet coefficients by multilevel wavelet analysis. The autocorrelation of the wavelet coefficients can clearly identify islanding detection, even in the variations of the grid voltage harmonics during normal operating conditions. The advantage of the proposed method is that it can detect islanding condition the conventional under voltage/over voltage/under frequency/over frequency methods fail to detect. The theoretical method to obtain wavelet energies is evolved and verified by the experimental result.

  10. Impact of manure fertilization on the abundance of antibiotic-resistant bacteria and frequency of detection of antibiotic resistance genes in soil and on vegetables at harvest.

    Science.gov (United States)

    Marti, Romain; Scott, Andrew; Tien, Yuan-Ching; Murray, Roger; Sabourin, Lyne; Zhang, Yun; Topp, Edward

    2013-09-01

    Consumption of vegetables represents a route of direct human exposure to bacteria found in soil. The present study evaluated the complement of bacteria resistant to various antibiotics on vegetables often eaten raw (tomato, cucumber, pepper, carrot, radish, lettuce) and how this might vary with growth in soil fertilized inorganically or with dairy or swine manure. Vegetables were sown into field plots immediately following fertilization and harvested when of marketable quality. Vegetable and soil samples were evaluated for viable antibiotic-resistant bacteria by plate count on Chromocult medium supplemented with antibiotics at clinical breakpoint concentrations. DNA was extracted from soil and vegetables and evaluated by PCR for the presence of 46 gene targets associated with plasmid incompatibility groups, integrons, or antibiotic resistance genes. Soil receiving manure was enriched in antibiotic-resistant bacteria and various antibiotic resistance determinants. There was no coherent corresponding increase in the abundance of antibiotic-resistant bacteria enumerated from any vegetable grown in manure-fertilized soil. Numerous antibiotic resistance determinants were detected in DNA extracted from vegetables grown in unmanured soil. A smaller number of determinants were additionally detected on vegetables grown only in manured and not in unmanured soil. Overall, consumption of raw vegetables represents a route of human exposure to antibiotic-resistant bacteria and resistance determinants naturally present in soil. However, the detection of some determinants on vegetables grown only in freshly manured soil reinforces the advisability of pretreating manure through composting or other stabilization processes or mandating offset times between manuring and harvesting vegetables for human consumption.

  11. High frequency energy measurements

    International Nuclear Information System (INIS)

    Stotlar, S.C.

    1981-01-01

    High-frequency (> 100 MHz) energy measurements present special problems to the experimenter. Environment or available electronics often limit the applicability of a given detector type. The physical properties of many detectors are frequency dependent and in some cases, the physical effect employed can be frequency dependent. State-of-the-art measurements generally involve a detection scheme in association with high-speed electronics and a method of data recording. Events can be single or repetitive shot requiring real time, sampling, or digitizing data recording. Potential modification of the pulse by the detector and the associated electronics should not be overlooked. This presentation will review typical applications, methods of choosing a detector, and high-speed detectors. Special considerations and limitations of some applications and devices will be described

  12. High-Resolution Physical Properties Logging of the AND-1B Sediment Core - Opportunity for Detecting High-Frequency Signals of Paleoenvironmental Changes

    Science.gov (United States)

    Niessen, F.; Magens, D.; Kuhn, G.; Helling, D.

    2008-12-01

    . Values range over several orders of magnitude from diatomites to 8000 (10-5 SI) in single clasts (mainly dolerite). Synchronous minima and maxima in both WBD and MS support dramatic changes in the depositional environment, driven by oscillations in ice extent in response to global climate fluctuations on orbital timescales. Superimposed on this, small-amplitude variations of high frequency are found within diatomite units. A rhythmic pattern of probably millennial to centennial pacing proposes an additional non-orbital forcing as control on system dynamics, at least during interglacials.

  13. The ability of NT-proBNP to detect chronic heart failure and predict all-cause mortality is higher in elderly Chinese coronary artery disease patients with chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Fu S

    2013-04-01

    Full Text Available Shihui Fu, Leiming Luo, Ping Ye, Shuangyan Yi, Yuan Liu, Bing Zhu, Liang Wang, Tiehui Xiao, Yongyi Bai Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, People's Republic of China Objective: To analyze the relationship between N-terminal pro-brain natriuretic peptide (NT-proBNP and renal function, and compare the ability and cut-off thresholds of NT-proBNP to detect chronic heart failure (CHF and predict mortality in elderly Chinese coronary artery disease (CAD patients with and without chronic kidney disease (CKD. Methods: The study included 999 CAD patients older than 60 years. The endpoint was all-cause mortality over a mean follow-up period of 417 days. Results: The median age was 86 years (range: 60–104 years, and the median NT-proBNP level was 409.8 pg/mL. CKD was present in 358 patients. Three hundred and six patients were positive for CHF. One hundred and ten CKD patients and 105 non-CKD patients died. Not only CKD, but also estimated glomerular filtration rate independently affected NT-proBNP. NT-proBNP detected CHF with a cut-off value of 298.4 pg/mL in non-CKD patients and a cut-off value of 435.7 pg/mL in CKD patients. NT-proBNP predicted death with a cut-off value of 369.5 pg/mL in non-CKD patients and a cut-off value of 2584.1 pg/mL in CKD patients. The NT-proBNP level was significantly related to the prevalence of CHF and all-cause mortality in CAD patients with and without CKD; this effect persisted after adjustment. The crude and multiple adjusted hazard ratios of NT-proBNP to detect CHF and predict mortality were significantly higher in patients with CKD compared with the remainder of the population. The addition of NT-proBNP to the three-variable and six-variable models generated a significant increase in the C-statistic. Conclusion: Amongst elderly Chinese CAD patients, there was an independently inverse association between NT-proBNP and renal function. With the higher cutoff points, NT

  14. A dual spectroscopic fluorescence probe based on carbon dots for detection of 2,4,6-trinitrophenol/Fe (III) ion by fluorescence and frequency doubling scattering spectra and its analytical applications.

    Science.gov (United States)

    Xu, Jinxia; Bai, Zhangjun; Zu, Fanlin; Yan, Fanyong; Wei, Junfu; Zhang, Saihui; Luo, Yunmei

    2018-07-05

    A convenient, highly sensitive and reliable assay for 2,4,6‑trinitrophenol (TNP) and Fe (III) ion (Fe 3+ ) in the dual spectroscopic manner is developed based on novel carbon dots (CDs). The CDs with highly blue emitting fluorescent were easily prepared via the one-step potassium hydroxide-assisted reflux method from dextrin. The as-synthesized CDs exhibited the high crystalline quality, the excellent fluorescence characteristics with a high quantum yield of ~13.1%, and the narrow size distribution with an average diameter of 6.3±0.5nm. Fluorescence and frequency doubling scattering (FDS) spectra of CDs show the unique changes in the presence of TNP/Fe 3+ by different mechanism. The fluorescence of CDs decre