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Sample records for polarimeter signals correlated

  1. Intrinsic coincident full-Stokes polarimeter using stacked organic photovoltaics and architectural comparison of polarimeter techniques

    Science.gov (United States)

    Yang, Ruonan; Sen, Pratik; O'Connor, B. T.; Kudenov, M. W.

    2017-08-01

    An intrinsic coincident full-Stokes polarimeter is demonstrated by using stain-aligned polymer-based organic photovoltaics (OPVs) which can preferentially absorb certain polarized states of incident light. The photovoltaic-based polarimeter is capable of measuring four stokes parameters by cascading four semitransparent OPVs in series along the same optical axis. Two wave plates were incorporated into the system to modulate the S3 stokes parameter so as to reduce the condition number of the measurement matrix. The model for the full-Stokes polarimeter was established and validated, demonstrating an average RMS error of 0.84%. The optimization, based on minimizing the condition number of the 4-cell OPV design, showed that a condition number of 2.4 is possible. Performance of this in-line polarimeter concept was compared to other polarimeter architectures, including Division of Time (DoT), Division of Amplitude (DoAm), Division of Focal Plane (DoFP), and Division of Aperture (DoA) from signal-to-noise ratio (SNR) perspective. This in-line polarimeter concept has the potential to enable both high temporal (as compared with a DoT polarimeter) and high spatial resolution (as compared with DoFP and DoA polarimeters). We conclude that the intrinsic design has the same √2 SNR advantage as the DoAm polarimeter, but with greater compactness.

  2. Correlation lifetimes of quiet and magnetic granulation from the SOUP instrument on Spacelab 2. [Solar Optical Universal Polarimeter

    Science.gov (United States)

    Title, A.; Tarbell, T.; Topka, K.; Acton, L.; Duncan, D.

    1988-01-01

    The time sequences of diffraction limited granulation images obtained by the Solar Optical Universal Polarimeter on Spacelab 2 are presented. The uncorrection autocorrelation limetime in magnetic regions is dominated by the 5-min oscillation. The removal of this oscillation causes the autocorrelation lifetime to increase by more than a factor of 2. The results suggest that a significant fraction of granule lifetimes are terminated by nearby explosions. Horizontal displacements and transverse velocities in the intensity field are measured. Lower limits to the lifetime in the quiet and magnetic sun are set at 440 s and 950 s, respectively.

  3. The Penn Polarimeters

    Directory of Open Access Journals (Sweden)

    Robert H. Koch

    2012-03-01

    Full Text Available This report describes the inception, development and extensive use over 30 years of elliptical polarimeters at the University of Pennsylvania. The initial Mark I polarimeter design utilized oriented retarder plates and a calcite Foster-Clarke prism as the analyzer. The Mark I polarimeter was used on the Kitt Peak 0.9 m in 1969-70 to accomplish a survey of approximately 70 objects before the device was relocated to the 0.72 m reflector at the Flower and Cook Observatory. Successive generations of automation and improvements included the early-80’s optical redesign to utilize a photoelastic modulated wave plate and an Ithaco lock-in amplifier–the photoelastic modulating polarimeter. The final design in 2000 concluded with a fully remote operable device. The legacy of the polarimetric programs includes studies of close binaries, pulsating hot stars, and luminous late-type variables.

  4. HERTZ, A Submillimeter Polarimeter

    Science.gov (United States)

    Schleuning, D. A.; Dowell, C. D.; Hildebrand, R. H.; Platt, S. R.; Novak, G.

    1997-03-01

    We describe a 32 pixel polarimeter, Hertz, for use at the Caltech Submillimeter Observatory. We present polarization maps of the Orion molecular cloud (OMC-1) at 350 \\mum (46 detections) and 450 \\mum (19 detections) with 3\\sigma or better statistical significance. The 350 \\mum polarization ranges from 1.4 to 6.8% with a median value of 3.3%. The position angles are fairly uniform across the souce at an angle of \\sim30 degrees (east of north). We describe the design and performance characteristics of the polarimeter and discuss systematic effects due to telescope and instrumental polarization, atmospheric fluctuations, and reference beam flux. (SECTION: Astronomical Instrumentation)

  5. Metasurface-Based Polarimeters

    Directory of Open Access Journals (Sweden)

    Fei Ding

    2018-04-01

    Full Text Available The state of polarization (SOP is an inherent property of light that can be used to gain crucial information about the composition and structure of materials interrogated with light. However, the SOP is difficult to experimentally determine since it involves phase information between orthogonal polarization states, and is uncorrelated with the light intensity and frequency, which can be easily determined with photodetectors and spectrometers. Rapid progress on optical gradient metasurfaces has resulted in the development of conceptually new approaches to the SOP characterization. In this paper, we review the fundamentals of and recent developments within metasurface-based polarimeters. Starting by introducing the concepts of generalized Snell’s law and Stokes parameters, we explain the Pancharatnam–Berry phase (PB-phase which is instrumental for differentiating between orthogonal circular polarizations. Then we review the recent progress in metasurface-based polarimeters, including polarimeters, spectropolarimeters, orbital angular momentum (OAM spectropolarimeters, and photodetector integrated polarimeters. The review is ended with a short conclusion and perspective for future developments.

  6. Correlation anlaysis of plasma fluctuation signals

    International Nuclear Information System (INIS)

    Wan Baonian; Wang Zhaoshen

    1987-01-01

    The application of correlation analysis to identify waves and instabilities in plasma is presented. First, the principle of correlation analysis and its application to diagnose plasma fluctuation signals are given. Then, the data acqusition system, application program and calibration method are described. Finally, experimental results from a mirror device are given

  7. PEM-based polarimeters for industrial applications

    Science.gov (United States)

    Wang, Baoliang

    2010-11-01

    A polarimeter is an optical instrument used in the transmissive mode for determining the polarization state of a light beam, or the polarization-altering properties of a sample, such as diattenuation, retardation and depolarizion.1 (Reflective "polarimeters" are typically called ellipsometers.) Polarimeters can, thus, be broadly categorized as either light-measuring polarimeters or sample-measuring polarimeters. A light-measuring polarimeter is also known as a Stokes polarimeter, which measures the polarization state of a light beam as described by the Stokes parameters. A sample-measuring polarimeter is also known as a Mueller polarimeter, which measures the complete set or a subset of polarization-altering properties of a sample. Polarimeters can also be categorized by whether they measure the complete set of polarization properties. If a Stokes polarimeter measures all four Stokes parameters, it is called a complete Stokes polarimeter; otherwise, an incomplete or a special Stokes polarimeter. Similarly, there are complete and incomplete Mueller polarimeters. Nearly all samplemeasuring polarimeters are incomplete or special polarimeters, particularly for industrial applications. These special polarimeters bear different names. For example, a circular dichroism spectrometer, which measures the differential absorption between left and right circularly polarized light (▵A= AL - AR), is a special polarimeter for measuring the circular diattenuation of a sample; a linear birefringence measurement system is a special polarimeter for measuring the linear retardation of a sample. Polarimeters have a broad range of applications in both academic research and industrial metrology. Polarimeters are applied to chemistry, biology, physics, astronomy, material science and many other scientific areas. Polarimeters are used as metrology tools in the semiconductor, fiber telecommunication, flat panel display, pharmaceutical and many other industries. Different branches of

  8. Proton polarimeters for spin transfer experiments

    International Nuclear Information System (INIS)

    McNaughton, M.W.

    1985-01-01

    The design and use of proton polarimeters for spin transfer (Wolfenstein parameter) measurements is discussed. Polarimeters are compared with polarized targets for spin dependent experiments. 32 refs., 4 figs

  9. Spectral line polarimetry with a channeled polarimeter.

    Science.gov (United States)

    van Harten, Gerard; Snik, Frans; Rietjens, Jeroen H H; Martijn Smit, J; Keller, Christoph U

    2014-07-01

    Channeled spectropolarimetry or spectral polarization modulation is an accurate technique for measuring the continuum polarization in one shot with no moving parts. We show how a dual-beam implementation also enables spectral line polarimetry at the intrinsic resolution, as in a classic beam-splitting polarimeter. Recording redundant polarization information in the two spectrally modulated beams of a polarizing beam-splitter even provides the possibility to perform a postfacto differential transmission correction that improves the accuracy of the spectral line polarimetry. We perform an error analysis to compare the accuracy of spectral line polarimetry to continuum polarimetry, degraded by a residual dark signal and differential transmission, as well as to quantify the impact of the transmission correction. We demonstrate the new techniques with a blue sky polarization measurement around the oxygen A absorption band using the groundSPEX instrument, yielding a polarization in the deepest part of the band of 0.160±0.010, significantly different from the polarization in the continuum of 0.2284±0.0004. The presented methods are applicable to any dual-beam channeled polarimeter, including implementations for snapshot imaging polarimetry.

  10. No-signaling, perfect bipartite dichotomic correlations and local randomness

    International Nuclear Information System (INIS)

    Seevinck, M. P.

    2011-01-01

    The no-signaling constraint on bi-partite correlations is reviewed. It is shown that in order to obtain non-trivial Bell-type inequalities that discern no-signaling correlations from more general ones, one must go beyond considering expectation values of products of observables only. A new set of nontrivial no-signaling inequalities is derived which have a remarkably close resemblance to the CHSH inequality, yet are fundamentally different. A set of inequalities by Roy and Singh and Avis et al., which is claimed to be useful for discerning no-signaling correlations, is shown to be trivially satisfied by any correlation whatsoever. Finally, using the set of newly derived no-signaling inequalities a result with potential cryptographic consequences is proven: if different parties use identical devices, then, once they have perfect correlations at spacelike separation between dichotomic observables, they know that because of no-signaling the local marginals cannot but be completely random.

  11. Signal and noise in financial correlation matrices

    Science.gov (United States)

    Burda, Zdzisław; Jurkiewicz, Jerzy

    2004-12-01

    Using Random Matrix Theory one can derive exact relations between the eigenvalue spectrum of the covariance matrix and the eigenvalue spectrum of its estimator (experimentally measured correlation matrix). These relations will be used to analyze a particular case of the correlations in financial series and to show that contrary to earlier claims, correlations can be measured also in the “random” part of the spectrum. Implications for the portfolio optimization are briefly discussed.

  12. Performance of neutron polarimeter SMART-NPOL

    International Nuclear Information System (INIS)

    Noji, S.; Miki, K.; Yako, K.; Kawabata, T.; Kuboki, H.; Sakai, H.; Sekiguchi, K.; Suda, K.

    2007-01-01

    The neutron polarimeter SMART-NPOL has been constructed at the RIKEN Accelerator Research Facility for measuring polarization correlations of proton-neutron systems. The SMART-NPOL system consists of 12 parallel neutron counter planes of two dimensionally position-sensitive plastic scintillators with a size of 60x60x3.0cm 3 . Polarimetry measurements were made using the analyzing power of the H1(n-vector,n)H1 reaction occurring in the plastic scintillators. The effective analyzing power of SMART-NPOL was measured with polarized neutrons from the zero-degree Li6(d-vector,n-vector) reaction with an incident deuteron energy of 135MeV/A. The effective analyzing power thus obtained was 0.26±0.01 stat ±0.03 syst and the double scattering efficiency was 1.1x10 -3

  13. Spectral Correlation of Multicarrier Modulated Signals and Its Application for Signal Detection

    Directory of Open Access Journals (Sweden)

    Zhang Haijian

    2010-01-01

    Full Text Available Spectral correlation theory for cyclostationary time-series signals has been studied for decades. Explicit formulas of spectral correlation function for various types of analog-modulated and digital-modulated signals are already derived. In this paper, we investigate and exploit the cyclostationarity characteristics for two kinds of multicarrier modulated (MCM signals: conventional OFDM and filter bank based multicarrier (FBMC signals. The spectral correlation characterization of MCM signal can be described by a special linear periodic time-variant (LPTV system. Using this LPTV description, we have derived the explicit theoretical formulas of nonconjugate and conjugate cyclic autocorrelation function (CAF and spectral correlation function (SCF for OFDM and FBMC signals. According to theoretical spectral analysis, Cyclostationary Signatures (CS are artificially embedded into MCM signal and a low-complexity signature detector is, therefore, presented for detecting MCM signal. Theoretical analysis and simulation results demonstrate the efficiency and robustness of this CS detector compared to traditionary energy detector.

  14. Processor operated correlator with applications to laser Doppler signals

    DEFF Research Database (Denmark)

    Bisgaard, C.; Johnsen, B.; Hassager, Ole

    1984-01-01

    A 64-channel correlator is designed with application to the processing of laser Doppler anemometry signals in the range 200 Hz to 250 kHz. The correlator is processor operated to enable the consecutive sampling of 448 correlation functions at a rate up to 500 Hz. Software is described to identify...

  15. Multichannel heterodyning for wideband interferometry, correlation and signal processing

    Science.gov (United States)

    Erskine, David J.

    1999-01-01

    A method of signal processing a high bandwidth signal by coherently subdividing it into many narrow bandwidth channels which are individually processed at lower frequencies in a parallel manner. Autocorrelation and correlations can be performed using reference frequencies which may drift slowly with time, reducing cost of device. Coordinated adjustment of channel phases alters temporal and spectral behavior of net signal process more precisely than a channel used individually. This is a method of implementing precision long coherent delays, interferometers, and filters for high bandwidth optical or microwave signals using low bandwidth electronics. High bandwidth signals can be recorded, mathematically manipulated, and synthesized.

  16. Laser-based capillary polarimeter.

    Science.gov (United States)

    Swinney, K; Hankins, J; Bornhop, D J

    1999-01-01

    A laser-based capillary polarimeter has been configured to allow for the detection of optically active molecules in capillary tubes with a characteristic inner diameter of 250 microm and a 39-nL (10(-9)) sample volume. The simple optical configuration consists of a HeNe laser, polarizing optic, fused-silica capillary, and charge-coupled device (CCD) camera in communication with a laser beam analyzer. The capillary scale polarimeter is based on the interaction between a polarized laser beam and a capillary tube, which results in a 360 degree fan of scattered light. This array of scattered light contains a set of interference fringe, which respond in a reproducible manner to changes in solute optical activity. The polarimetric utility of the instrument will be demonstrated by the analysis of two optically active solutes, R-mandelic acid and D-glucose, in addition to the nonoptically active control, glycerol. The polarimetric response of the system is quantifiable with detection limits facilitating 1.7 x 10(-3) M or 68 x 10(-12) nmol (7 psi 10(-9) g) sensitivity.

  17. SAR image enhancement via post-correlation signal processing

    Science.gov (United States)

    Matthews, N. D.; Kaupp, V. H.; Waite, W. P.; Macdonald, H. C.

    1984-01-01

    Seventeen interpreters ranked sets of computer-generated radar imagery to assess the value of post-correlation processing on the interpretability of SAR (synthetic aperture radar) imagery. The post-correlation processing evaluated amounts to a nonlinear mapping of the signal exiting a digital correlator and allows full use of signal bandwidth for improving the spatial resolution or for noise reduction. The results indicate that it is reasonable to hypothesize an optimal SAR presentation format for specific applications even though this study was too limited to be specific.

  18. Simple modification of Compton polarimeter to redirect synchrotron radiation

    Directory of Open Access Journals (Sweden)

    J. Benesch

    2015-11-01

    Full Text Available Synchrotron radiation produced as an electron beam passes through a bending magnet is a significant source of background in many experiments. Using modeling, we show that simple modifications of the magnet geometry can reduce this background by orders of magnitude in some circumstances. Specifically, we examine possible modifications of the four dipole magnets used in Jefferson Lab’s Hall A Compton polarimeter chicane. This Compton polarimeter has been a crucial part of experiments with polarized beams and the next generation of experiments will utilize increased beam energies, up to 11 GeV, requiring a corresponding increase in Compton dipole field to 1.5 T. In consequence, the synchrotron radiation (SR from the dipole chicane will be greatly increased. Three possible modifications of the chicane dipoles are studied; each design moves about 2% of the integrated bending field to provide a gentle bend in critical regions along the beam trajectory which, in turn, greatly reduces the synchrotron radiation within the acceptance of the Compton polarimeter photon detector. Each of the modifications studied also softens the SR energy spectrum at the detector sufficiently to allow shielding with 5 mm of lead. Simulations show that these designs are each capable of reducing the background signal due to SR by three orders of magnitude. The three designs considered vary in their need for vacuum vessel changes and in their effectiveness.

  19. MHD marking using the MSE polarimeter optics in ILW JET plasmas

    CERN Document Server

    Reyes Cortes, S.; Alves, D.; Baruzzo, M.; Bernardo, J.; Buratti, P.; Coelho, R.; Challis, C.; Chapman, I.; Hawkes, N.; Hender, T.C.; Hobirk, J.; Joffrin, E.

    2016-01-01

    In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms. A variety of experimental examples in JET ITER-Like Wall (ILW) plasmas are presented, providing an adequate picture and interpretation for the MSE optics polarimeter technique.

  20. Compressed Sensing with Linear Correlation Between Signal and Measurement Noise

    DEFF Research Database (Denmark)

    Arildsen, Thomas; Larsen, Torben

    2014-01-01

    Existing convex relaxation-based approaches to reconstruction in compressed sensing assume that noise in the measurements is independent of the signal of interest. We consider the case of noise being linearly correlated with the signal and introduce a simple technique for improving compressed...... sensing reconstruction from such measurements. The technique is based on a linear model of the correlation of additive noise with the signal. The modification of the reconstruction algorithm based on this model is very simple and has negligible additional computational cost compared to standard......-rate quantization of compressed measurements, which is known to introduce correlated noise, and improvements in reconstruction error compared to ordinary Basis Pursuit De-Noising of up to approximately 7 dB are observed for 1 bit/sample quantization. Furthermore, the proposed method is compared to Binary Iterative...

  1. Hard X-ray Photoelectric Polarimeter

    Data.gov (United States)

    National Aeronautics and Space Administration — Our objective is to determine the gas mixtures and pressures that would enable a sensitive, hard X-ray polarimeter using existing flight components with the goal of...

  2. The Compton polarimeter at ELSA

    International Nuclear Information System (INIS)

    Doll, D.

    1998-06-01

    In order to measure the degree of transverse polarization of the stored electron beam in the Electron Stretcher Accelerator ELSA a compton polarimeter is built up. The measurement is based on the polarization dependent cross section for the compton scattering of circular polarized photons off polarized electrons. Using a high power laser beam and detecting the scattered photons a measuring time of two minutes with a statistical error of 5% is expected from numerical simulations. The design and the results of a computer controlled feedback system to enhance the laser beam stability at the interaction point in ELSA are presented. The detection of the scattered photons is based on a lead converter and a silicon-microstrip detector. The design and test results of the detector module including readout electronic and computer control are discussed. (orig.)

  3. Polarimeter for the General Fusion SPECTOR machine

    Energy Technology Data Exchange (ETDEWEB)

    Carle, Patrick, E-mail: patrick.carle@generalfusion.com; Froese, Aaron; Wong, Adrian; Howard, Stephen; O’Shea, Peter; Laberge, Michel [General Fusion, Inc., Burnaby, British Columbia V3N4T5 (Canada)

    2016-11-15

    A polarimeter has been designed to measure Faraday rotation and help to understand the profile of its safety factor, q, on the recently built SPECTOR magnetized target fusion machine at General Fusion. The polarimeter uses two counter-rotating, circularly polarized, 118.8 μm beams to probe the plasma. Grad-Shafranov simulations have been used to investigate the effect of measurement error and chord geometry.

  4. Correlation analysis of respiratory signals by using parallel coordinate plots.

    Science.gov (United States)

    Saatci, Esra

    2018-01-01

    The understanding of the bonds and the relationships between the respiratory signals, i.e. the airflow, the mouth pressure, the relative temperature and the relative humidity during breathing may provide the improvement on the measurement methods of respiratory mechanics and sensor designs or the exploration of the several possible applications in the analysis of respiratory disorders. Therefore, the main objective of this study was to propose a new combination of methods in order to determine the relationship between respiratory signals as a multidimensional data. In order to reveal the coupling between the processes two very different methods were used: the well-known statistical correlation analysis (i.e. Pearson's correlation and cross-correlation coefficient) and parallel coordinate plots (PCPs). Curve bundling with the number intersections for the correlation analysis, Least Mean Square Time Delay Estimator (LMS-TDE) for the point delay detection and visual metrics for the recognition of the visual structures were proposed and utilized in PCP. The number of intersections was increased when the correlation coefficient changed from high positive to high negative correlation between the respiratory signals, especially if whole breath was processed. LMS-TDE coefficients plotted in PCP indicated well-matched point delay results to the findings in the correlation analysis. Visual inspection of PCB by visual metrics showed range, dispersions, entropy comparisons and linear and sinusoidal-like relationships between the respiratory signals. It is demonstrated that the basic correlation analysis together with the parallel coordinate plots perceptually motivates the visual metrics in the display and thus can be considered as an aid to the user analysis by providing meaningful views of the data. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Role of the null space of the DRM in the performance of modulated polarimeters.

    Science.gov (United States)

    LaCasse, Charles F; Tyo, J Scott; Chipman, Russell A

    2012-03-15

    Imaging polarimeters infer the spatial distribution of the polarization state of the optical field as a function of time and/or wavelength. A polarimeter indirectly determines the polarization state by first modulating the intensity of the light field and then demodulating the measured data to infer the polarization parameters. This Letter considers passive Stokes parameter polarimeters and their inversion methods. The most widely used method is the data reduction matrix (DRM), which builds up a matrix equation that can be inverted to find the polarization state from a set of intensity measurements. An alternate strategy uses linear system formulations that allow band limited reconstruction through a filtering perspective. Here we compare these two strategies for overdetermined polarimeters and find that design of the null space of the inversion operator provides degrees of freedom to optimize the trade off between accuracy and signal-to-noise ratio. We further describe adaptive filtering techniques that could optimize the reconstruction for a particular experimental configuration. This Letter considers time-varying Stokes parameters, but the methods apply equally to polarimeters that are modulated in space or in wavelength.

  6. Calibration of Correlation Radiometers Using Pseudo-Random Noise Signals

    Directory of Open Access Journals (Sweden)

    Sebastián Pantoja

    2009-08-01

    Full Text Available The calibration of correlation radiometers, and particularly aperture synthesis interferometric radiometers, is a critical issue to ensure their performance. Current calibration techniques are based on the measurement of the cross-correlation of receivers’ outputs when injecting noise from a common noise source requiring a very stable distribution network. For large interferometric radiometers this centralized noise injection approach is very complex from the point of view of mass, volume and phase/amplitude equalization. Distributed noise injection techniques have been proposed as a feasible alternative, but are unable to correct for the so-called “baseline errors” associated with the particular pair of receivers forming the baseline. In this work it is proposed the use of centralized Pseudo-Random Noise (PRN signals to calibrate correlation radiometers. PRNs are sequences of symbols with a long repetition period that have a flat spectrum over a bandwidth which is determined by the symbol rate. Since their spectrum resembles that of thermal noise, they can be used to calibrate correlation radiometers. At the same time, since these sequences are deterministic, new calibration schemes can be envisaged, such as the correlation of each receiver’s output with a baseband local replica of the PRN sequence, as well as new distribution schemes of calibration signals. This work analyzes the general requirements and performance of using PRN sequences for the calibration of microwave correlation radiometers, and particularizes the study to a potential implementation in a large aperture synthesis radiometer using an optical distribution network.

  7. Hard X-ray Imaging Polarimeter for PolariS

    Science.gov (United States)

    Hayashida, Kiyoshi

    2016-07-01

    We present the current status of development of hard X-ray imaging polarimeters for the small satellite mission PolariS. The primary aim of PolariS is hard X-ray (10-80keV) polarimetry of sources brighter than 10mCrab. Its targets include stellar black holes, neutron stars, super nova remnants, and active galactic nuclei. This aim is enabled with three sets of hard X-ray telescopes and imaging polarimeters installed on their focal planes. The imaging polarimeter consists of two kinds of (plastic and GSO) scintillator pillars and multi-anode photo multiplier tubes (MAPMTs). When an X-ray photon incident to a plastic scintillator cause a Compton scattering, a recoiled electron makes a signal on the corresponding MAPMT pixel, and a scatted X-rays absorbed in surrounding GSO makes another signal. This provide information on the incident position and the scattered direction. The latter information is employed for polarimetry. For 20keV X-ray incidence, the recoiled electron energy is as low as 1keV. Thus, the performance of this imaging polarimeter is primarily determined by the efficiency that we can detect low level signal of recoiled electrons generated in plastic scintillators. The efficiency could depend on multiple factors, e.g. quenching of light in scintillators, electric noise, pedestal error, cross talk of the lights to adjacent MAPMT pixels, MAPMT dark current etc. In this paper, we examined these process experimentally and optimize the event selection algorithm, in which single photo-electron events are selected. We then performed an X-ray (10-80keV monochromatic polarized beam) irradiation test at a synchrotron facility. The modulation contrast (M) is about 60% in 15-80keV range. We succeeded in detecting recoiled electrons for 10-80keV X-ray incidence, though detection efficiency is lower at lowest end of the energy range. Expected MDP will also be shown.

  8. Neural correlates of success and failure signals during neurofeedback learning.

    Science.gov (United States)

    Radua, Joaquim; Stoica, Teodora; Scheinost, Dustin; Pittenger, Christopher; Hampson, Michelle

    2016-04-05

    Feedback-driven learning, observed across phylogeny and of clear adaptive value, is frequently operationalized in simple operant conditioning paradigms, but it can be much more complex, driven by abstract representations of success and failure. This study investigates the neural processes involved in processing success and failure during feedback learning, which are not well understood. Data analyzed were acquired during a multisession neurofeedback experiment in which ten participants were presented with, and instructed to modulate, the activity of their orbitofrontal cortex with the aim of decreasing their anxiety. We assessed the regional blood-oxygenation-level-dependent response to the individualized neurofeedback signals of success and failure across twelve functional runs acquired in two different magnetic resonance sessions in each of ten individuals. Neurofeedback signals of failure correlated early during learning with deactivation in the precuneus/posterior cingulate and neurofeedback signals of success correlated later during learning with deactivation in the medial prefrontal/anterior cingulate cortex. The intensity of the latter deactivations predicted the efficacy of the neurofeedback intervention in the reduction of anxiety. These findings indicate a role for regulation of the default mode network during feedback learning, and suggest a higher sensitivity to signals of failure during the early feedback learning and to signals of success subsequently. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  9. Correlation of Respiratory Signals and Electrocardiogram Signals via Empirical Mode Decomposition

    KAUST Repository

    El Fiky, Ahmed Osama

    2011-05-24

    Recently Electrocardiogram (ECG) signals are being broadly used as an essential diagnosing tool in different clinical applications as they carry a reliable representation not only for cardiac activities, but also for other associated biological processes, like respiration. However, the process of recording and collecting them has usually suffered from the presence of some undesired noises, which in turn affects the reliability of such representations.Therefore, de-noising ECG signals became a hot research field for signal processing experts to ensure better and clear representation of the different cardiac activities. Given the nonlinear and non-stationary properties of ECGs, it is not a simple task to cancel the undesired noise terms without affecting the biological physics of them. In this study, we are interested in correlating the ECG signals with respiratory parameters, specifically the lung volume and lung pressure. We have focused on the concept of de-noising ECG signals by means of signal decomposition using an algorithm called the Empirical Mode Decomposition (EMD) where the original ECG signals are being decomposed into a set of intrinsic mode functions (IMF). Then, we have provided criteria based on which some of these IMFs have been adapted to reconstruct de-noised ECG version. Finally, we have utilized de-noised ECGs as well as IMFs for to study the correlation with lung volume and lung pressure. These correlation studies have showed some clear resemblance especially between the oscillations of ECGs and lung pressures.

  10. A Burst Chasing X-ray Polarimeter

    Science.gov (United States)

    Hill, Joanne; Hill, Joe; Barthelmy, S.; Black, K.; Deines-Jones, P.; Jahoda, K.; Sakamoto, T.; Kaaret, P.; McConnell, M.; Bloser, P.; hide

    2007-01-01

    Tihs is a viewgraph presentation of a discussion of the X-ray Polarimeter. Gamma-ray bursts are one of the most powerful explosions in the universe and have been detected out to distances of almost 13 billion light years. The exact origin of these energetic explosions is still unknown but the resulting huge release of energy is thought to create a highly relativistic jet of material and a power-law distribution of electrons. There are several theories describing the origin of the prompt GRB emission that currently cannot be distinguished. Measurements of the linear polarization would provide unique and important constraints on the mechanisms thought to drive these powerful explosions. We present the design of a sensitive, and extremely versatile gamma-ray burst polarimeter. The instrument is a photoelectric polarimeter based on a time-projection chamber. The photoelectric time-projection technique combines high sensitivity with broad band-pass and is potentially the most powerful method between 2 and 100 keV where the photoelectric effect is the dominant interaction process We present measurements of polarized and unpolarized X-rays obtained with a prototype detector and describe the two mission concepts, the Gamma-Ray Burst Polarimeter (GRBP) for thc U S Naval Academy satellite MidSTAR-2, and thc Low Energy Polarimeter (LEP) onboard POET, a broadband polarimetry concept for a small explorer mission.

  11. Methodological Framework for Estimating the Correlation Dimension in HRV Signals

    Directory of Open Access Journals (Sweden)

    Juan Bolea

    2014-01-01

    Full Text Available This paper presents a methodological framework for robust estimation of the correlation dimension in HRV signals. It includes (i a fast algorithm for on-line computation of correlation sums; (ii log-log curves fitting to a sigmoidal function for robust maximum slope estimation discarding the estimation according to fitting requirements; (iii three different approaches for linear region slope estimation based on latter point; and (iv exponential fitting for robust estimation of saturation level of slope series with increasing embedded dimension to finally obtain the correlation dimension estimate. Each approach for slope estimation leads to a correlation dimension estimate, called D^2, D^2⊥, and D^2max. D^2 and D^2max estimate the theoretical value of correlation dimension for the Lorenz attractor with relative error of 4%, and D^2⊥ with 1%. The three approaches are applied to HRV signals of pregnant women before spinal anesthesia for cesarean delivery in order to identify patients at risk for hypotension. D^2 keeps the 81% of accuracy previously described in the literature while D^2⊥ and D^2max approaches reach 91% of accuracy in the same database.

  12. A CAMAC-resident microprocessor for the monitoring of polarimeter spin states

    International Nuclear Information System (INIS)

    Reid, D.; DuPlantis, D.; Yoder, N.; Dale, D.

    1992-01-01

    A CAMAC module for the reporting of polarimeter spin states is being developed using a resident microcontroller. The module will allow experimenters at the Indiana University Cyclotron Facility to monitor spin states and correlate spin information with other experimental data. The use of a microprocessor allows for adaptation of the module as new requirements ensue without change to the printed circuit board layout. (author)

  13. PoET: Polarimeters for Energetic Transients

    Science.gov (United States)

    McConnell, Mark; Barthelmy, Scott; Hill, Joanne

    2008-01-01

    This presentation focuses on PoET (Polarimeters for Energetic Transients): a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment - GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The PoET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. PoET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  14. Microprocessor Card for Cuban Series polarimeters Laserpol

    International Nuclear Information System (INIS)

    Arista Romeu, E.; Mora Mazorra, W.

    2012-01-01

    We present the design consists of a card based on a micro-processor 8-bit adds new software components and their basic living, which allow to deliver new services and expand the possibilities for use in other applications of the polarimeter LASERPOL series, as the polarimetric detection. Given the limitations of the original card it was necessary to introduce a series of changes that would allow to address new user requirements, and expand the possible applications of the instruments. This was done the expansion of the capacity of the EPROM and RAM memory, the decoder circuit was implemented memory map using a programmable integrated circuit, and introduced a real time clock with nonvolatile RAM, these features are exploited to the introduction of new features such as the realization of the polarimeter calibration by the user from a sample pattern or a calibration pattern used as a reference, and the incorporation of the time and date to the reports of measurements required industry for quality control processes. Card that is achieved along with the rest of the components is compatible with polarimeters LASERPOL 101M Series, 3M and LP4, pin to pin, which facilitates their incorporation into the polarimeters in operation in the industry 'in situ' replacement cards from previous models, allowing to extend the possibilities of statistical processing, precision and accuracy of the instruments. Improved measurements in the industry, resulting in significant savings by elimination of losses in production and raw materials. The improved response speed of reading the polarimeters LASERPOL Use and polarimetric detectors. (Author)

  15. Fluctuations of noiselike signals reflected from a rough surface at the output of a correlation receiver

    Science.gov (United States)

    Gulin, E. P.

    2005-11-01

    The frequency and time averaging of the fluctuations that occur in the cross-correlation function of a radiated noiselike acoustic signal with the signal received after its reflection from a rough water surface is considered. The variance and temporal correlation function are calculated for the output effect of a correlation receiver for different ratios between the averaging time and the time correlation interval of fluctuations, the band width of the radiated signal, and the frequency correlation interval of the transfer function fluctuations.

  16. Use of proportional tubes in a muon polarimeter

    International Nuclear Information System (INIS)

    Kenney, C.J.; Eckhause, M.; Ginkel, J.F.

    1988-01-01

    A prototype muon polarimeter was built to study the feasibility of measuring the positive muon polarization in the decay K/sub L/ → μ + μ/sup /minus//. The system consisted of alternating layers of extruded aluminum gas proportional tubes and polarization-retaining absorber plates of either aluminum or marble. Longitudinally polarized positive muons from the Stopped Muon Channel at the Clinton P. Anderson Meson Physics Facility (LAMPF) were stopped in the absorber plates where they precessed in a field of 60 gauss. Decay times were recorded in 100 ns first-in-first-out memories for all wires hit during a 12.8 μs period centered about the muon stop trigger. The performance of the system was studied for different beam rates and absorber thicknesses. The value of imposing time and spacial cuts on track data to enhance the precession signal was also investigated. 7 refs., 4 figs., 1 tab

  17. Patterns statistical correlation between electrocardiographic signals and phonocardiographic

    OpenAIRE

    Rodriguez, Jose Luis; Garcia, Julio Cesar

    2006-01-01

     Research in the field of bio-signals has spread largely to the digital signal processing, which currently offers powerful tools that enable development and evolution, which is why in recent decades have implemented various techniques in analyzing biomedical signals that allow diagnoses that were not possible before. In the following article statistical analysis it was performed such that signal segments corresponding to ECG and PCG (SCG), in order to find common patterns between them and sub...

  18. Imaging polarimetry of circumstellar environments with the Extreme Polarimeter

    NARCIS (Netherlands)

    Rodenhuis, M.; Canovas, H.; Jeffers, S.V.; Min, M.; Keller, C.U.

    2010-01-01

    Three successful observation campaigns have been conducted with the Extreme Polarimeter, an imaging polarimeter for the study of circumstellar environments in scattered light at visible wavelengths. A contrast ratio between the central star and the circumstellar source of 10-5 can be achieved with

  19. SPIDER: Probing the Early Universe with a Suborbital Polarimeter

    Science.gov (United States)

    Fraisse, Aurélien A.; SPIDER Collaboration

    2012-01-01

    SPIDER is a balloon-borne polarimeter designed to detect a divergence-free polarization pattern ("B-modes") in the Cosmic Microwave Background (CMB). In the inflationary scenario, the spectrum of the tensor perturbations that generate this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. The expected level of systematic error in the SPIDER instrument is significantly below the amplitude of an interesting cosmological B-mode signal with r=0.03. An optimized scanning strategy enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while providing access to a relatively wide range of angular scales. In the SPIDER field, the polarized emission from interstellar dust is as bright or brighter than the cosmological r=0.03 B-mode signal at all SPIDER frequencies (90, 150, and 280 GHz), a situation similar to that found in the "Southern Hole." Despite this foreground contamination, two 20-day flights of the SPIDER instrument will constrain the amplitude of the B-mode signal to rAPRA-NNX07AL64G), the National Science Foundation (ANT-1043515), the Gordon and Betty Moore Foundation, and the David and Lucile Packard Foundation. Support in Canada is provided by NSERC, the Canadian Space Agency, the Canada Foundation for Innovation, and CIFAR.

  20. Cryogenic system for liquid hydrogen polarimeter

    International Nuclear Information System (INIS)

    Kitami, T.; Chiba, M.; Hirabayashi, H.; Ishii, T.; Kato, S.

    1979-01-01

    A cryogenic system has been constructed for a liquid hydrogen polarimeter in order to measure polarization of high energy proton at the 1.3 GeV electron synchrotron of Institute for Nuclear Study, University of Tokyo. The system principally consists of a cryogenerator with a cryogenic transfer line, a liquid hydrogen cryostat, and a 14.5 l target container of thin aluminum alloy where liquid hydrogen is served for the experiment. The refrigeration capacity is about 54 W at 20.4 K without a target container. (author)

  1. Multichannel far-infrared interferometer/polarimeter

    International Nuclear Information System (INIS)

    Young, P.E.

    1984-01-01

    Studies of the time development of the current density profile in a tokamak plasma have been incomplete due to the lack of adequate, direct measurements of the internal magnetic field. Experimental confirmation of anomalous current penetration during the startup phase of a tokamak discharge and the detailed study of major disruptions and their relation to the presence of tearing modes are needed to complete the understanding of tokamak confinement properties. The major obstacle to studies of the tokamak current density profile has been the lack of a reliable, nonperturbing diagnostic. This dissertation describes a multichannel interferometer/polarimeter that was developed for this purpose

  2. The atmosphere- and hydrosphere-correlated signals in GPS observations

    Science.gov (United States)

    Bogusz, Janusz; Boy, Jean-Paul; Klos, Anna; Figurski, Mariusz

    2015-04-01

    analysis of satellite data was performed twofold: firstly, the time series from network solution (NS) processed in Bernese 5.0 software by the Military University of Technology EPN Local Analysis Centre, secondly, the ones from PPP (Precise Point Positioning) from JPL (Jet Propulsion Laboratory) processing in Gipsy-Oasis were analyzed. Both were modelled with wavelet decomposition with Meyer orthogonal mother wavelet. Here, nine levels of decomposition were applied and eighth detail of it was interpreted as changes close to one year. In this way, both NS and PPP time series where presented as curves with annual period with amplitudes and phases changeable in time. The same analysis was performed for atmospheric (ATM) and hydrospheric (HYDR) models. All annual curves (modelled from NS, PPP, ATM and HYDR) were then compared to each other to investigate whether GPS observations contain the atmosphere and hydrosphere correlated signals and in what way the amplitudes of them may disrupt the GPS time series.

  3. A fast Stokes polarimeter: preliminary design

    Science.gov (United States)

    Vaughn, Israel J.; Alenin, Andrey S.; Tyo, J. Scott

    2017-09-01

    Designing polarimetric systems directly in the channel space has provided insight into how to design new types of polarimetric systems, including systems which use carriers in hybrid domains of space, time, or spectrum. Utilizing linear systems theory, we present a full Stokes imaging polarimeter design which has the potential to operate at half the frame rate of the imaging sensor of the system by utilizing a hybrid spatio-temporal carrier design. The design places channels on the faces and the edges of the Nyquist cube resulting in the potential for half the Nyquist limit to be achieved, provided that the spatial frequency of the objects being imaged are bandlimited to less than 0.25 cycles per pixel. If the objects are not spatially bandlimited, then the achievable temporal bandwidth is more difficult to analyze. However, a spatio-temporal tradeoff still exists allowing for increased temporal bandwidth. We present the design of a "Fast Stokes'' polarimeter and some simulated images using this design.

  4. Active polarimeter optical system laser hazard analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Augustoni, Arnold L.

    2005-07-01

    A laser hazard analysis was performed for the SNL Active Polarimeter Optical System based on the ANSI Standard Z136.1-2000, American National Standard for Safe Use of Lasers and the ANSI Standard Z136.6-2000, American National Standard for Safe Use of Lasers Outdoors. The Active Polarimeter Optical System (APOS) uses a pulsed, near-infrared, chromium doped lithium strontium aluminum fluoride (Cr:LiSAF) crystal laser in conjunction with a holographic diffuser and lens to illuminate a scene of interest. The APOS is intended for outdoor operations. The system is mounted on a height adjustable platform (6 feet to 40 feet) and sits atop a tripod that points the beam downward. The beam can be pointed from nadir to as much as 60 degrees off of nadir producing an illuminating spot geometry that can vary from circular (at nadir) to elliptical in shape (off of nadir). The JP Innovations crystal Cr:LiSAF laser parameters are presented in section II. The illuminating laser spot size is variable and can be adjusted by adjusting the separation distance between the lens and the holographic diffuser. The system is adjusted while platform is at the lowest level. The laser spot is adjusted for a particular spot size at a particular distance (elevation) from the laser by adjusting the separation distance (d{sub diffuser}) to predetermined values. The downward pointing angle is also adjusted before the platform is raised to the selected operation elevation.

  5. Analysis, optimization and implementation of a variable retardance based polarimeter

    Directory of Open Access Journals (Sweden)

    Moreno I.

    2010-06-01

    Full Text Available We present a comprehensive analysis, optimization and implementation of a Stokes polarimeter based on two liquid crystals acting as variable retarders. For the optimization process, the Conditional Number or the Equally Weighted Variance indicators are applied and compared as a function of different number of polarization analyzers. Moreover, some of the optimized polarimeter configurations are experimentally implemented and the influence of small experimental deviations from the optimized configuration values on the amplification of the Stokes component error is also studied. Some experimental results obtained by using the implemented polarimeters, when measuring different incidence states of polarization, are provided.

  6. BILF1 Mediated Transformation Correlates with Constitutive Signaling

    DEFF Research Database (Denmark)

    Lyngaa, Rikke Birgitte

    2009-01-01

    BIFL1 is a G protein-coupled receptor encoded by human EBV. It signals constitutively through G_alpha_i and is an orphan receptor known to down regulate MHCI expression. BILF1 also engage in dimerization with several chemokine receptors and it induced the activity of NF-kappa beta and inhibits...... the phosphorylation of PKR. My research on BILF1 has contributed to increase the knowledge of BILF1 signaling and has identified BILF1 as a potential oncogene. During the proteomics study NFAT was identified as being up-regulated in BILF1 expressing cells eventually revealing an increased NFAT activity induced...

  7. MAPK signaling correlates with the antidepressant effects of ketamine.

    Science.gov (United States)

    Réus, Gislaine Z; Vieira, Flavio Geraldo; Abelaira, Helena M; Michels, Monique; Tomaz, Débora B; dos Santos, Maria Augusta B; Carlessi, Anelise S; Neotti, Morgana V; Matias, Beatriz I; Luz, Jaíne R; Dal-Pizzol, Felipe; Quevedo, João

    2014-08-01

    Studies have pointed to a relationship between MAPK kinase (MEK) signaling and the behavioral effects of antidepressant drugs. So, in the present study we examined the behavioral and molecular effects of ketamine, an antagonist of the N-methyl-d-aspartate receptor (NMDA), which has been shown to have an antidepressant effect after the inhibition of MEK signaling in Wistar rats. Our results showed that acute administration of the MEK inhibitor PD184161, produced depressive-like behavior and stopped antidepressant-like effects of ketamine in the forced swimming test. The phosphorylation of extracellular signal-regulated kinase 1/2 (pERK 1/2) was decreased by PD184161 in the amygdala and nucleus accumbens, and the effects of ketamine on pERK 1/2 in the prefrontal cortex and hippocampus were inhibited by PD184161. The ERK 2 levels were decreased by PD184161 in the nucleus accumbens; and the effects of ketamine were blocked in this brain area. The p38 protein kinase (p38MAPK) and proBDNF were inhibited by PD184161, and the MEK inhibitor prevented the effects of ketamine in the nucleus accumbens. In addition, ketamine increased pro-BDNF levels in the hippocampus. In conclusion, our findings demonstrated that an acute blockade of MAPK signaling lead to depressive-like behavior and stopped the antidepressant response of ketamine, suggesting that the effects of ketamine could be mediated, at least in part, by the regulation of MAPK signaling in these specific brain areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Statistical measures of Planck scale signal correlations in interferometers

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Craig J. [Univ. of Chicago, Chicago, IL (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Kwon, Ohkyung [Univ. of Chicago, Chicago, IL (United States)

    2015-06-22

    A model-independent statistical framework is presented to interpret data from systems where the mean time derivative of positional cross correlation between world lines, a measure of spreading in a quantum geometrical wave function, is measured with a precision smaller than the Planck time. The framework provides a general way to constrain possible departures from perfect independence of classical world lines, associated with Planck scale bounds on positional information. A parametrized candidate set of possible correlation functions is shown to be consistent with the known causal structure of the classical geometry measured by an apparatus, and the holographic scaling of information suggested by gravity. Frequency-domain power spectra are derived that can be compared with interferometer data. As a result, simple projections of sensitivity for specific experimental set-ups suggests that measurements will directly yield constraints on a universal time derivative of the correlation function, and thereby confirm or rule out a class of Planck scale departures from classical geometry.

  9. Optical polarimeter based on Fourier analysis and electronic control

    International Nuclear Information System (INIS)

    Vilardy, J; Salas, V.; Torres, C.

    2016-01-01

    In this paper, we show the design and implementation of an optical polarimeter using electronic control and the Fourier analysis. The polarimeter prototype will be used as a main tool for the students of the Universidad Popular del Cesar that belong to the following university programs: Electronics engineering (optoelectronics area), Math and Physics degree and the Master in Physics Sciences, in order to learning the theory and experimental aspects of the state of optical polarization via the Stokes vector measurement. Using the electronic polarimeter proposed in this paper, the students will be able to observe (in an optical bench) and understand the different interactions of the states of optical polarization when the optical waves pass through to the polarizers and retarder waves plates. The electronic polarimeter has a software that captures the optical intensity measurement and evaluates the Stokes vector. (Author)

  10. Electro-Optic Imaging Fourier Transform Spectral Polarimeter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Boulder Nonlinear Systems, Inc. (BNS) proposes to develop an Electro-Optic Imaging Fourier Transform Spectral Polarimeter (E-O IFTSP). The polarimetric system is...

  11. Gamma-Ray Imager Polarimeter for Solar Flares Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose here to develop the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS), the next-generation instrument for high-energy solar observations. GRIPS will...

  12. MOPTOP: Multi-colour Optimised Optical Polarimeter

    Science.gov (United States)

    Jermak, Helen; Steele, Iain A.; Smith, Robert J.

    Polarimetric measurements are essential for the study of jetted sources associated with black holes, such as γ-ray bursts and blazars. The relativistic jets launched from regions close to the black hole are threaded with magnetic fields, which produce synchrotron emission, and can be studied with polarimetric measurements. The multi-colour, optimised, optical polarimeter (MOPTOP) is a multi-band imaging instrument designed for use on the Liverpool Telescope. By replacing the rotating polaroid with a half wave plate and beam splitter, the instrument utilises twice as much of the incoming beam of light from the telescope compared to its predecessor, Ringo3. MOPTOP also builds on the successful introduction of dichroic mirrors to perform simultaneous multi-waveband polarimetric and photometric analysis in Ringo3, and enhances the sensitivity of the instrument with sCMOS cameras to use all photons as efficiently as possible.

  13. The SLAC E-154 {sup 3}He polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, E.W. [California Institute of Technology, Pasadena, California 91125 (United States); Chupp, T.E.; Coulter, K.P.; Smith, T.B.; Welsh, R. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Thompson, A.K. [National Institute of Standards and Technology, Gainesville, Maryland 20899 (United States); Romalis, M.V.; Bogorad, P.L.; Cates, G.D.; Kumar, K.S. [Princeton University, Princeton, New Jersey 08544 (United States); Johnson, J.R. [University of Wisconsin, Madison, Wisconsin 53706 (United States)

    1998-01-01

    We describe the NMR and Rb Zeeman frequency shift polarimeters used for determining the {sup 3}He polarization in a recent precision measurement of the neutron spin structure function g{sub 1} at SLAC (E-154). We performed a detailed study of the systematic errors associated with the calibration of the NMR polarimeter. A new technique was used for determining the {sup 3}He polarization from the frequency shift of the Rb Zeeman resonance. {copyright} {ital 1998 American Institute of Physics.}

  14. Hand gesture recognition based on signals cross-correlation

    OpenAIRE

    Adda, Mo; Lekova, Anna

    2015-01-01

    Interactive gestures and body movements let us control and interact mobile devices, screens and robots. Vision-based gesture recognition systems analyze the detected infrared and visible light after converting them into some measurable signal, e.g. voltage or current. Since, infrared and visible light are electromagnetic waves (EMW) with particular wavelength between 0.4 and 1.6μm, we introduce a concept of a new kind of sensor for direct perception of EMW to see objects. We propose a novel f...

  15. Optoelectronic polarimeter controlled by a graphical user interface of Matlab

    International Nuclear Information System (INIS)

    Vilardy, J M; Torres, R; Jimenez, C J

    2017-01-01

    We show the design and implementation of an optical polarimeter using electronic control. The polarimeter has a software with a graphical user interface (GUI) that controls the optoelectronic setup and captures the optical intensity measurement, and finally, this software evaluates the Stokes vector of a state of polarization (SOP) by means of the synchronous detection of optical waves. The proposed optoelectronic polarimeter can determine the Stokes vector of a SOP in a rapid and efficient way. Using the polarimeter proposed in this paper, the students will be able to observe (in an optical bench) and understand the different interactions of the SOP when the optical waves pass through to the linear polarizers and retarder waves plates. The polarimeter prototype could be used as a main tool for the students in order to learn the theory and experimental aspects of the SOP for optical waves via the Stokes vector measurement. The proposed polarimeter controlled by a GUI of Matlab is more attractive and suitable to teach and to learn the polarization of optical waves. (paper)

  16. Adaptive endpoint detection of seismic signal based on auto-correlated function

    International Nuclear Information System (INIS)

    Fan Wanchun; Shi Ren

    2001-01-01

    Based on the analysis of auto-correlation function, the notion of the distance between auto-correlation function was quoted, and the characterization of the noise and the signal with noise were discussed by using the distance. Then, the method of auto- adaptable endpoint detection of seismic signal based on auto-correlated similarity was summed up. The steps of implementation and determining of the thresholds were presented in detail. The experimental results that were compared with the methods based on artificial detecting show that this method has higher sensitivity even in a low signal with noise ratio circumstance

  17. Correlation characteristics of signals reflected by the wavy surface of ocean in mirror direction

    Science.gov (United States)

    Zhitkovskiy, Y. Y.; Nosov, A. V.; Savelyev, V. V.

    1985-06-01

    An experimental study was carried out to determine the correlation characteristics of pseudonoise signals reflected from a wave-covered surface in the mirror direction. The major measured quantity was the reciprocal correlation coefficient between the transmitted signal and the reflected signal. The transmitter was lowered from a ship on a 150 m cable. The receiver and preamplifier were lowered to the same depth from a buoy which was allowed to drift from the ship to a distance of 100-500 m, the changing distance changing the angle of the beam reflected from the surface of the ocean back down to the hydrophone. The radiator transmitted a pulsed signal with a pseudonoise carrier. The results were interpreted within the framework of ordinary correlation theory by processing several recordings, calculating the sign and ordinary correlation coefficients to determine the variation in sign correlation coefficient as a function of the ordinary correlation coefficient. Graphs of the average variation are presented. It was found that the medium did not distort the signal as it propagated through the water mass (within the limits of experimental accuracy). The correlation coefficient between the transmitted and reflected signals is thus determined entirely by the characteristics of reradiation of the sound by the wavecovered surface.

  18. Correlation analyses between volatiles and glucosinolates show no evidence for chemical defense signaling in Brassica rapa

    Directory of Open Access Journals (Sweden)

    Florian Paul Schiestl

    2014-04-01

    Full Text Available Positive correlations between volatile organic compounds (VOCs and defense chemicals indicate signaling of defense status. Such aposematic signaling has been hypothesized to be widespread in plants, however, it has up to now only been shown for visual signals. Correlations between identical compounds in different plant tissues, on the other hand, can be informative about the (co-regulation of their biosynthesis or emission. Here I use Brassica rapa to investigate 1 correlations between identical metabolites (volatiles, glucosinolates in leaf and flower tissue, and 2 correlations between volatiles and glucosinolates in the same plant organs (flowers and leaves. Whereas the amounts of many glucosinolates were positively correlated in leaves and flower tissue, identical leaf and floral VOCs showed no such correlations, indicating independent regulation of emission. None of the leaf or flower volatiles showed positive correlations with the two major glucosinolates (gluconapin, glucobrassicanapin or the sum of all glucosinolates in either leaves or flowers. Some VOCs, however, showed positive correlations with minor glucosinolates which, however, represented less than one percent of the total amounts of glucosinolates. Some leaf monoterpenes showed negative associations with gluconapin. The lack of consistent positive correlations between VOCs and major defense compounds suggests that plants do not chemically signal their defense status. This could be adaptive as it may avoid eavesdropping by specialist herbivores to locate their host plants. Negative correlations likely indicate chemical trade-offs in the synthesis of secondary metabolites.

  19. Super-resolution for imagery from integrated microgrid polarimeters.

    Science.gov (United States)

    Hardie, Russell C; LeMaster, Daniel A; Ratliff, Bradley M

    2011-07-04

    Imagery from microgrid polarimeters is obtained by using a mosaic of pixel-wise micropolarizers on a focal plane array (FPA). Each distinct polarization image is obtained by subsampling the full FPA image. Thus, the effective pixel pitch for each polarization channel is increased and the sampling frequency is decreased. As a result, aliasing artifacts from such undersampling can corrupt the true polarization content of the scene. Here we present the first multi-channel multi-frame super-resolution (SR) algorithms designed specifically for the problem of image restoration in microgrid polarization imagers. These SR algorithms can be used to address aliasing and other degradations, without sacrificing field of view or compromising optical resolution with an anti-aliasing filter. The new SR methods are designed to exploit correlation between the polarimetric channels. One of the new SR algorithms uses a form of regularized least squares and has an iterative solution. The other is based on the faster adaptive Wiener filter SR method. We demonstrate that the new multi-channel SR algorithms are capable of providing significant enhancement of polarimetric imagery and that they outperform their independent channel counterparts.

  20. Correlation techniques for the improvement of signal-to-noise ratio in measurements with stochastic processes

    CERN Document Server

    Reddy, V R; Reddy, T G; Reddy, P Y; Reddy, K R

    2003-01-01

    An AC modulation technique is described to convert stochastic signal variations into an amplitude variation and its retrieval through Fourier analysis. It is shown that this AC detection of signals of stochastic processes when processed through auto- and cross-correlation techniques improve the signal-to-noise ratio; the correlation techniques serve a similar purpose of frequency and phase filtering as that of phase-sensitive detection. A few model calculations applied to nuclear spectroscopy measurements such as Angular Correlations, Mossbauer spectroscopy and Pulse Height Analysis reveal considerable improvement in the sensitivity of signal detection. Experimental implementation of the technique is presented in terms of amplitude variations of harmonics representing the derivatives of normal spectra. Improved detection sensitivity to spectral variations is shown to be significant. These correlation techniques are general and can be made applicable to all the fields of particle counting where measurements ar...

  1. Correlation of Solar X-ray Flux and SID Modified VLF Signal Strength

    Science.gov (United States)

    2015-03-26

    the 1930s by Hans Mögel, a German physicist working for Transradio in Berlin [ Mitra 1974]. This type of event causes degradation of received signals ...also lost in the signal fluctuations. All of this had to be considered in processing and analysis, to distinguish valid SID data from erroneous data...copyright protection in the United States. AFIT-ENP-MS-15-M-077 CORRELATION OF SOLAR X-RAY FLUX AND SID MODIFIED VLF SIGNAL STRENGTH

  2. Cross-correlation of bio-signals using continuous wavelet transform and genetic algorithm.

    Science.gov (United States)

    Sukiennik, Piotr; Białasiewicz, Jan T

    2015-05-30

    Continuous wavelet transform allows to obtain time-frequency representation of a signal and analyze short-lived temporal interaction of concurrent processes. That offers good localization in both time and frequency domain. Scalogram and coscalogram analysis of two signal interaction dynamics gives an indication of the cross-correlation of analyzed signals in both domains. We have used genetic algorithm with a fitness function based on signals convolution to find time delay between investigated signals. Two methods of cross-correlation are proposed: one that finds single delay for analyzed signals, and one returns a vector of delay values for each of wavelet transform sub-band center frequencies. Algorithms were implemented using MATLAB. We have extracted the data of simultaneously recorded encephalogram and arterial blood pressure and have investigated their interaction dynamics. We found time delay whose value cannot be precisely determined by scalograms and coscalogram inspection. The biomedical signals used come from MIMIC database. Cross-correlation of two complex signals is commonly performed using fast Fourier transform. It works well for signals with invariant frequency content. We have determined the time delay between analyzed signals using wavelet scalograms and we have accordingly shifted one of them, aligning associated events. Their coscalogram indicates the cross-correlation of the associated events. Introducing new methods of wavelet transform in cross-correlation analysis has proven to be beneficial to the gain of the information about process interaction. Introduced solutions could be used to reason about causality between processes and gain bigger insight regarding analyzed systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Performance of the PRAXyS X-ray polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Iwakiri, W.B., E-mail: wataru.iwakiri@riken.jp [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Black, J.K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Rock Creek Scientific, 1400 East-West Hwy, Silver Spring, MD 20910 (United States); Cole, R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Enoto, T. [The Hakubi Center for Advanced Research, Kyoto University, Kyoto 606-8302 (Japan); Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Hayato, A. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hill, J.E.; Jahoda, K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kaaret, P. [University of Iowa, Iowa City, IA 52242 (United States); Kitaguchi, T. [Department of Physical Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kubota, M. [Department of Physics, Tokyo University of Science, 3-1 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan. (Japan); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Marlowe, H.; McCurdy, R. [University of Iowa, Iowa City, IA 52242 (United States); Takeuchi, Y. [Department of Physics, Tokyo University of Science, 3-1 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan. (Japan); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tamagawa, T. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, Tokyo University of Science, 3-1 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan. (Japan)

    2016-12-01

    The performance of the Time Projection Chamber (TPC) polarimeter for the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) Small Explorer was evaluated using polarized and unpolarized X-ray sources. The PRAXyS mission will enable exploration of the universe through X-ray polarimetry in the 2–10 keV energy band. We carried out performance tests of the polarimeter at the Brookhaven National Laboratory, National Synchrotron Light Source (BNL-NSLS) and at NASA's Goddard Space Flight Center. The polarimeter was tested with linearly polarized, monochromatic X-rays at 11 different energies between 2.5 and 8.0 keV. At maximum sensitivity, the measured modulation factors at 2.7, 4.5 and 8.0 keV are 27%, 43% and 59%, respectively and the measured angle of polarization is consistent with the expected value at all energies. Measurements with a broadband, unpolarized X-ray source placed a limit of less than 1% on false polarization in the PRAXyS polarimeter.

  4. The rocket experiment demonstration of a soft x-ray polarimeter (REDSoX Polarimeter)

    Science.gov (United States)

    Marshall, Herman L.; Schulz, Norbert S.; Trowbridge Heine, Sarah N.; Heilmann, Ralf K.; Günther, H. Moritz; Egan, Mark; Hellickson, Tim; Schattenburg, Mark; Chakrabarty, Deepto; Windt, David L.; Gullikson, Eric M.; Ramsey, Brian D.; Weisskopf, Martin; Tagliaferri, Gianpiero; Pareschi, Giovanni; Marscher, Alan; Jorstad, Svetlana

    2017-08-01

    The Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX Polarimeter) is a sounding rocket instrument that can make the first measurement of the linear X-ray polarization of an extragalactic source in the 0.2-0.8 keV band as low as 10%. We employ multilayer-coated mirrors as Bragg reflectors at the Brewster angle. By matching the dispersion of a spectrometer using replicated optics from MSFC and critical angle transmission gratings from MIT to three laterally graded multilayer mirrors (LGMLs), we achieve polarization modulation factors over 90%. We present a novel arrangement of gratings, designed optimally for the purpose of polarimetry with a converging beam. The entrance aperture is divided into six equal sectors; pairs of blazed gratings from opposite sectors are oriented to disperse to the same LGML. The LGML position angles are 120 degrees to each other. CCD detectors then measure the intensities of the dispersed spectra after reflection and polarizing by the LGMLs, giving the three Stokes parameters needed to determine a source's linear polarization fraction and orientation. A current grant is funding further development to improve the LGMLs. Sample gratings for the project have been fabricated at MIT and the development team continues to improve them under separate funding. Our technological approach is the basis for a possible orbital mission

  5. Low Computational Signal Acquisition for GNSS Receivers Using a Resampling Strategy and Variable Circular Correlation Time

    Science.gov (United States)

    Zhang, Yeqing; Wang, Meiling; Li, Yafeng

    2018-01-01

    For the objective of essentially decreasing computational complexity and time consumption of signal acquisition, this paper explores a resampling strategy and variable circular correlation time strategy specific to broadband multi-frequency GNSS receivers. In broadband GNSS receivers, the resampling strategy is established to work on conventional acquisition algorithms by resampling the main lobe of received broadband signals with a much lower frequency. Variable circular correlation time is designed to adapt to different signal strength conditions and thereby increase the operation flexibility of GNSS signal acquisition. The acquisition threshold is defined as the ratio of the highest and second highest correlation results in the search space of carrier frequency and code phase. Moreover, computational complexity of signal acquisition is formulated by amounts of multiplication and summation operations in the acquisition process. Comparative experiments and performance analysis are conducted on four sets of real GPS L2C signals with different sampling frequencies. The results indicate that the resampling strategy can effectively decrease computation and time cost by nearly 90–94% with just slight loss of acquisition sensitivity. With circular correlation time varying from 10 ms to 20 ms, the time cost of signal acquisition has increased by about 2.7–5.6% per millisecond, with most satellites acquired successfully. PMID:29495301

  6. Low Computational Signal Acquisition for GNSS Receivers Using a Resampling Strategy and Variable Circular Correlation Time

    Directory of Open Access Journals (Sweden)

    Yeqing Zhang

    2018-02-01

    Full Text Available For the objective of essentially decreasing computational complexity and time consumption of signal acquisition, this paper explores a resampling strategy and variable circular correlation time strategy specific to broadband multi-frequency GNSS receivers. In broadband GNSS receivers, the resampling strategy is established to work on conventional acquisition algorithms by resampling the main lobe of received broadband signals with a much lower frequency. Variable circular correlation time is designed to adapt to different signal strength conditions and thereby increase the operation flexibility of GNSS signal acquisition. The acquisition threshold is defined as the ratio of the highest and second highest correlation results in the search space of carrier frequency and code phase. Moreover, computational complexity of signal acquisition is formulated by amounts of multiplication and summation operations in the acquisition process. Comparative experiments and performance analysis are conducted on four sets of real GPS L2C signals with different sampling frequencies. The results indicate that the resampling strategy can effectively decrease computation and time cost by nearly 90–94% with just slight loss of acquisition sensitivity. With circular correlation time varying from 10 ms to 20 ms, the time cost of signal acquisition has increased by about 2.7–5.6% per millisecond, with most satellites acquired successfully.

  7. Low Computational Signal Acquisition for GNSS Receivers Using a Resampling Strategy and Variable Circular Correlation Time.

    Science.gov (United States)

    Zhang, Yeqing; Wang, Meiling; Li, Yafeng

    2018-02-24

    For the objective of essentially decreasing computational complexity and time consumption of signal acquisition, this paper explores a resampling strategy and variable circular correlation time strategy specific to broadband multi-frequency GNSS receivers. In broadband GNSS receivers, the resampling strategy is established to work on conventional acquisition algorithms by resampling the main lobe of received broadband signals with a much lower frequency. Variable circular correlation time is designed to adapt to different signal strength conditions and thereby increase the operation flexibility of GNSS signal acquisition. The acquisition threshold is defined as the ratio of the highest and second highest correlation results in the search space of carrier frequency and code phase. Moreover, computational complexity of signal acquisition is formulated by amounts of multiplication and summation operations in the acquisition process. Comparative experiments and performance analysis are conducted on four sets of real GPS L2C signals with different sampling frequencies. The results indicate that the resampling strategy can effectively decrease computation and time cost by nearly 90-94% with just slight loss of acquisition sensitivity. With circular correlation time varying from 10 ms to 20 ms, the time cost of signal acquisition has increased by about 2.7-5.6% per millisecond, with most satellites acquired successfully.

  8. Signal void dots on T2-weighted brain MR imaging: correlation with hypertensive brain lesions

    International Nuclear Information System (INIS)

    Yoo, Dong Soo; Jeong, Chun Keun; Kim, Sang Joon; Lee, Young Seok; Kim, Jae Il; Kwon, Ho Jang

    1998-01-01

    To evaluate the relationship of signal void dots seen on T2-weighted images with hypertension, hypertensive intracerebral hemorrhage and infarction. MR images of 73 consecutive patients with signal void dots on T2-weighted images were reviewed. Seventy-three randomly selected age-matched patients without signal void dot lesion were also reviewed. We evaluated 1) the location and number of signal void dots;2) the frequency of hypertension among patients and controls; 3) the frequency of associated brain parenchymal abnormalities (hypertensive intracerebra hemorrhage, microangiopathy and infarction) in both groups; 4) the relationship between the number of signal void dots and associated brain lesions in the patient group. Signal void dots numbered 1-50(average, 12), and were found mostly in the thalamus, basal ganglis, and the pons. Hypertension(97.1%), hypertensive ICH(43.8%) and microangiopathy(96%) were frequent in patients with signal void dots, the number of which correlated with the severity of microangiopathy. Infarction(13.7%), however, did not correlate with dots. Signal void dots correlate closely with hypertension, hypertensive ICH, and microangiopathy. They may indicate hypertensive brain change.=20

  9. An improvement in SAR image interpretability provided by post-correlation signal processing

    Science.gov (United States)

    Matthews, N. D.; Kaupp, V. H.; Waite, W. P.; Macdonald, H. C.

    1983-01-01

    A presentation on the basis of subjective analysis of computer-generated SAR imagery depicts the improvement in interpretability obtained by post-correlation signal processing. A parametric study was conducted to determine the improvement in interpretability obtained by the application of signal weighting functions on the post-processed returns. The results suggest that a marked improvement in interpretability results from symmetrizing the exponential distribution of the fading signal. Preliminary analysis indicates that signal weighting improves the contrast ratio between the mean value of adjacent homogeneous regions in a SAR scene.

  10. Design of a polarimeter for slow e sup + beams

    CERN Document Server

    Kumita, T; Hamatsu, R; Hirose, M; Hirose, T; Irako, M; Kawasaki, N; Yang, J

    2000-01-01

    A polarimeter which utilizes ortho-positronium quenching in a magnetic field is used to measure polarization of slow positron beams. This polarimeter is employed for a polarization measurement at an e sup + beam system where the beam is provided from the beta sup + decay of sup 2 sup 7 Si produced via the sup 2 sup 7 Al(p,n) sup 2 sup 7 Si reaction caused by proton irradiation. The beam polarization is determined to be 38.4+-4.0(statistical)+-8.7(systematic)%.

  11. A variable energy Moeller polarimeter at the S-DALINAC

    Energy Technology Data Exchange (ETDEWEB)

    Barday, Roman; Enders, Joachim [Institut fuer Kernphysik, TU Darmstadt (Germany); Mueller, Wolfgang; Steiner, Bastian [Institut fuer Theorie Elektromagnetischer Felder, TU Darmstadt (Germany)

    2008-07-01

    A coincidence Moeller polarimeter is designed for both cw and pulsed beam of the Superconducting Darmstadt Linear Accelerator S-DALINAC where polarized electron beams will become available in 2008. The designed polarimeter covers an energy region between 15 and 130 MeV. The beam polarisation at currents of up to 1 {mu}A is inferred from measurement of the asymmetry in polarized electron-electron scattering from the Fe-Co foil. The influence of the atomic motion of the target electrons on the polarisation, the so-called Levchuk effect was investigated.

  12. Non-linear canonical correlation for joint analysis of MEG signals from two subjects

    Directory of Open Access Journals (Sweden)

    Cristina eCampi

    2013-06-01

    Full Text Available We consider the problem of analysing magnetoencephalography (MEG data measured from two persons undergoing the same experiment, and we propose a method that searches for sources with maximally correlated energies. Our method is based on canonical correlation analysis (CCA, which provides linear transformations, one for each subject, such that the correlation between the transformed MEG signals is maximized. Here, we present a nonlinear version of CCA which measures the correlation of energies. Furthermore, we introduce a delay parameter in the modelto analyse, e.g., leader-follower changes in experiments where the two subjects are engaged in social interaction.

  13. Gating based on internal/external signals with dynamic correlation updates

    Energy Technology Data Exchange (ETDEWEB)

    Wu Huanmei [Purdue School of Engineering and Technology, Indiana University School of Informatics, IUPUI, Indianapolis, IN (United States); Zhao Qingya [School of Health Sciences, Purdue University, West Lafayette, IN (United States); Berbeco, Ross I [Department of Radiation Oncology, Dana-Farber/Brigham and Womens Cancer Center and Harvard Medical School, Boston, MA (United States); Nishioka, Seiko [NTT East-Japan Sapporo Hospital, Sapporo (Japan); Shirato, Hiroki [Hokkaido University Graduate School of Medicine, Sapporo (Japan); Jiang, Steve B [Department of Radiation Oncology, School of Medicine, University of California, San Diego, CA (United States)], E-mail: hw9@iupui.edu, E-mail: sbjiang@ucsd.edu

    2008-12-21

    Precise localization of mobile tumor positions in real time is critical to the success of gated radiotherapy. Tumor positions are usually derived from either internal or external surrogates. Fluoroscopic gating based on internal surrogates, such as implanted fiducial markers, is accurate however requiring a large amount of imaging dose. Gating based on external surrogates, such as patient abdominal surface motion, is non-invasive however less accurate due to the uncertainty in the correlation between tumor location and external surrogates. To address these complications, we propose to investigate an approach based on hybrid gating with dynamic internal/external correlation updates. In this approach, the external signal is acquired at high frequency (such as 30 Hz) while the internal signal is sparsely acquired (such as 0.5 Hz or less). The internal signal is used to validate and update the internal/external correlation during treatment. Tumor positions are derived from the external signal based on the newly updated correlation. Two dynamic correlation updating algorithms are introduced. One is based on the motion amplitude and the other is based on the motion phase. Nine patients with synchronized internal/external motion signals are simulated retrospectively to evaluate the effectiveness of hybrid gating. The influences of different clinical conditions on hybrid gating, such as the size of gating windows, the optimal timing for internal signal acquisition and the acquisition frequency are investigated. The results demonstrate that dynamically updating the internal/external correlation in or around the gating window will reduce false positive with relatively diminished treatment efficiency. This improvement will benefit patients with mobile tumors, especially greater for early stage lung cancers, for which the tumors are less attached or freely floating in the lung.

  14. Detection of non-stationary leak signals at NPP primary circuit by cross-correlation analysis

    International Nuclear Information System (INIS)

    Shimanskij, S.B.

    2007-01-01

    A leak-detection system employing high-temperature microphones has been developed for the RBMK and ATR (Japan) reactors. Further improvement of the system focused on using cross-correlation analysis of the spectral components of the signal to detect a small leak at an early stage of development. Since envelope processes are less affected by distortions than are wave processes, they give a higher-degree of correlation and can be used to detect leaks with lower signal-noise ratios. Many simulation tests performed at nuclear power plants have shown that the proposed methods can be used to detect and find the location of a small leak [ru

  15. A 400ch SCPC signal demodulator using chirp transform and correlation detection scheme

    Science.gov (United States)

    Kohri, Takeharu; Morikura, Masahiro; Kato, Shuzo

    A group demodulator for PSK-FDMA (phase-shift-keyed frequency-division multiple access) signals using a chirp transform is proposed for hardware and power consumption reduction of demodulators at a hub station. The proposed demodulator uses a chirp filter for FDM/TDM transform of received PSK-FDMA signals and demodulates TDM transform signals by recovering each channel carrier and clock. Since the chirp filter works as an analog correlator, the transform TDM signals have the maximum S/N (signal-to-noise) ratio at the sampling instant, achieving 2 b/s/Hz frequency utilization efficiency with a QPSK (quadrature phase-shift keyed) modulation scheme. The feasibility test results on the prototype 400-channel demodulator show a good agreement with theory. The proposed group demodulator can contribute to reduce significantly hardware size and power consumption of hub stations.

  16. MRI of intracranial meningiomas: correlations with T2 signal intensity and histopathologic findings

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Oh Keun; Kim, Chang Soo; Lee, Seung Ro; Hong, Eun Kyung; Hahm, Chang Kok [College of Medicine, Hanyang University, Seoul (Korea, Republic of)

    1995-05-15

    To correlate histologic subtypes with MR signal intensity in meningioma and to find etiologic factors responsible for the signal characteristics of T2WI. We reviewed MRIs and histopathologic studies in 35 cases of meningioma. MR signal intensity was measured with respect to cerebral cortex (gray matter) as hypointense, isointense, or hyperintense. Pathologically, meningioma was classified into subtypes, according to the new WHO classification or brain tumors. The degree of cellularity, collagen, and vascularity was graded from 1 to 3, and presence or absence of psammoma bodies, microcysts, micronecrosis and microhemorrhage was observed. Multiple linear regression analysis was done to find relationship between the pathologic findings and MR signal intensity of T2WI. Even in the same subtype, cellularity, collagen and vascularity of the tumor were different. T1WI was not useful in discriminating pathologic subtype because most tumors were isointense or hypointense to the cortex regardless of histologic type. Most tumors showed various signal intensity on T2WI, but T2WI were not useful, either. Exceptionally, all five cases of microcystic meningiomas were hyperintense on T2W1. In analysing the relationship between MR signal intensity and pathologic factor, increased collagen content produced decreased signal intensity ({rho} < 0.01) and the existence of microcyst resulted in high signal intensity ({rho} < 0.01). Cellularity, vascularity, microcalcification, micronecrosis and microhemorrhage had no relationship with signal intensity on T2WI. Except for the five microcystic meningiomas with hyperintensity on T2WI there was no relationship between MR signal intensity and subtype of meningiomas. Pathologic factors influencing T2 signal intensity were microcyst and collagen. Even in the same subtypes of meningiomas, the T2 signal intensity was different. This may be due to different ratio of microcyst and collagen.

  17. The Skylab ten color photoelectric polarimeter. [sky brightness

    Science.gov (United States)

    Weinberg, J. L.; Hahn, R. C.; Sparrow, J. G.

    1975-01-01

    A 10-color photoelectric polarimeter was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, and the spacecraft corona. A description is given of the instrument and observing routines together with initial results on the spacecraft corona and polarization of the zodiacal light.

  18. Polarisation at HERA. Reanalysis of the HERA II polarimeter data

    Energy Technology Data Exchange (ETDEWEB)

    Sobloher, B.; Behnke, T.; Olsson, J.; Pitzl, D.; Schmitt, S.; Tomaszewska, J.; Fabbri, R.

    2012-01-15

    In this technical note we briefly present the analysis of the HERA polarimeters (transversal and longitudinal) as of summer 2011. We present the final reanalysis of the TPOL data, and discuss the systematic uncertainties. A procedure to combine and average LPOL and TPOL data is presented. (orig.)

  19. Polarisation at HERA. Reanalysis of the HERA II polarimeter data

    International Nuclear Information System (INIS)

    Sobloher, B.; Behnke, T.; Olsson, J.; Pitzl, D.; Schmitt, S.; Tomaszewska, J.; Fabbri, R.

    2012-01-01

    In this technical note we briefly present the analysis of the HERA polarimeters (transversal and longitudinal) as of summer 2011. We present the final reanalysis of the TPOL data, and discuss the systematic uncertainties. A procedure to combine and average LPOL and TPOL data is presented. (orig.)

  20. An optimized photoelectron track reconstruction method for photoelectric X-ray polarimeters

    Science.gov (United States)

    Kitaguchi, Takao; Black, Kevin; Enoto, Teruaki; Fukazawa, Yasushi; Hayato, Asami; Hill, Joanne E.; Iwakiri, Wataru B.; Jahoda, Keith; Kaaret, Philip; McCurdy, Ross; Mizuno, Tsunefumi; Nakano, Toshio; Tamagawa, Toru

    2018-02-01

    We present a data processing algorithm for angular reconstruction and event selection applied to 2-D photoelectron track images from X-ray polarimeters. The method reconstructs the initial emission angle of a photoelectron from the initial portion of the track, which is obtained by continuously cutting a track until the image moments or number of pixels fall below tunable thresholds. In addition, event selection which rejects round tracks quantified with eccentricity and circularity is performed so that polarimetry sensitivity considering a trade-off between the modulation factor and signal acceptance is maximized. The modulation factors with applying track selection are 26 . 6 ± 0 . 4, 46 . 1 ± 0 . 4, 62 . 3 ± 0 . 4, and 61 . 8 ± 0 . 3% at 2.7, 4.5, 6.4, and 8.0 keV, respectively, using the same data previously analyzed by Iwakiri et al. (2016), where the corresponding numbers are 26 . 9 ± 0 . 4, 43 . 4 ± 0 . 4, 54 . 4 ± 0 . 3, and 59 . 1 ± 0 . 3%. The method improves polarimeter sensitivity by 5%-10% at the high energy end of the band previously presented (Iwakiri et al. 2016).

  1. A Michelson interferometer/polarimeter on the Tokamak Fusion Test Reactor (TFTR)

    International Nuclear Information System (INIS)

    Park, H.K.; Mansfield, D.K.; Johnson, L.C.; Ma, C.H.

    1987-01-01

    A multichannel interferometer/polarimeter for the Tokamak Fusion Test Reactor (TFTR) has been developed in order to study the time dependent plasma current density (J/sub p/) and electron density (n/sub e/) profile simultaneously. The goal of the TFTR is demonstration of breakeven via dueuterium and tritium (DT) plasma. In order to be operated and maintained during DT operation phase, the system is designed based on the Michelson geometry which possesses intrinsic standing wave problems. So far, there has been no observable signals due to these standing waves. However, a standing wave resulted from the beam path design to achieve a optimum use of the laser power was found. This standing wave has not prevented initial 10 channel interferometer operation. However, a single channel polarimeter test indicated this standing wave was fatal for Faraday notation measurements. Techniques employing 1/2 wave plates and polarizers have been applied to eliminate this standing wave problem. The completion of 10 channel Faraday rotation measurements may be feasible in the near future

  2. Developmental changes of BOLD signal correlations with global human EEG power and synchronization during working memory.

    Directory of Open Access Journals (Sweden)

    Lars Michels

    Full Text Available In humans, theta band (5-7 Hz power typically increases when performing cognitively demanding working memory (WM tasks, and simultaneous EEG-fMRI recordings have revealed an inverse relationship between theta power and the BOLD (blood oxygen level dependent signal in the default mode network during WM. However, synchronization also plays a fundamental role in cognitive processing, and the level of theta and higher frequency band synchronization is modulated during WM. Yet, little is known about the link between BOLD, EEG power, and EEG synchronization during WM, and how these measures develop with human brain maturation or relate to behavioral changes. We examined EEG-BOLD signal correlations from 18 young adults and 15 school-aged children for age-dependent effects during a load-modulated Sternberg WM task. Frontal load (in-dependent EEG theta power was significantly enhanced in children compared to adults, while adults showed stronger fMRI load effects. Children demonstrated a stronger negative correlation between global theta power and the BOLD signal in the default mode network relative to adults. Therefore, we conclude that theta power mediates the suppression of a task-irrelevant network. We further conclude that children suppress this network even more than adults, probably from an increased level of task-preparedness to compensate for not fully mature cognitive functions, reflected in lower response accuracy and increased reaction time. In contrast to power, correlations between instantaneous theta global field synchronization and the BOLD signal were exclusively positive in both age groups but only significant in adults in the frontal-parietal and posterior cingulate cortices. Furthermore, theta synchronization was weaker in children and was--in contrast to EEG power--positively correlated with response accuracy in both age groups. In summary we conclude that theta EEG-BOLD signal correlations differ between spectral power and

  3. Ranging accuracy improvement of time-correlated signal-photon counting lidar

    Science.gov (United States)

    Zhang, Zijing; Zhao, Yuan; Zhang, Jiandong; Cen, Longzhu; Li, Shuo; Sun, Yifei; Wang, Feng

    2017-11-01

    Lidar based on Geiger-mode Avalanche Photodiode Detector (Gm-APD), also called Gm-APD Lidar for short, has the advantages of the ultra-high sensitivity and ranging accuracy, and therefore it is widely used in the weak signal detection over a long distance. Time-Correlated Single Photon Counting (TCSPC) is a more commonly used signal processing method of Gm-APD Lidar. However, after each avalanche response, Gm-APD needs a certain time to quench avalanche current, which is called the dead time. In the dead time, Gm-APD can't response any signal. This will result in the uneven response by Gm-APD, and the response probability of the front of the echo pulse signal is higher than that of the back of the echo pulse signal. The peak of photon counting results will deviate from the real peak of the echo signal, and this deviation will become larger with the increase of the echo pulse width. In many application environments (for example, underwater, battlefield smoke, fog and dust, etc.), the broadening effect of the echo pulse signal is obvious, and this will seriously impact the ranging accuracy of Gm-APD Lidar. In this paper, an improved method uses the multi-gate detection to response the complete waveform of the echo pulse signal, and thus improves the ranging accuracy of GmAPD due to obtaining more accurate echo pulse peak.

  4. An Adaptive Model for Calculating the Correlation Degree of Multiple Adjacent Signalized Intersections

    Directory of Open Access Journals (Sweden)

    Linhong Wang

    2013-01-01

    Full Text Available As an important component of the urban adaptive traffic control system, subarea partition algorithm divides the road network into some small subareas and then determines the optimal signal control mode for each signalized intersection. Correlation model is the core of subarea partition algorithm because it can quantify the correlation degree of adjacent signalized intersections and decides whether these intersections can be grouped into one subarea. In most cases, there are more than two intersections in one subarea. However, current researches only focus on the correlation model for two adjacent intersections. The objective of this study is to develop a model which can calculate the correlation degree of multiple intersections adaptively. The cycle lengths, link lengths, number of intersections, and path flow between upstream and downstream coordinated phases were selected as the contributing factors of the correlation model. Their jointly impacts on the performance of the coordinated control mode relative to the isolated control mode were further studied using numerical experiments. The paper then proposed a correlation index (CI as an alternative to relative performance. The relationship between CI and the four contributing factors was established in order to predict the correlation, which determined whether adjacent intersections could be partitioned into one subarea. A value of 0 was set as the threshold of CI. If CI was larger than 0, multiple intersections could be partitioned into one subarea; otherwise, they should be separated. Finally, case studies were conducted in a real-life signalized network to evaluate the performance of the model. The results show that the CI simulates the relative performance well and could be a reliable index for subarea partition.

  5. Performance of Narrowband Signal Detection under Correlated Rayleigh Fading Based on Synthetic Array

    Directory of Open Access Journals (Sweden)

    Ali Broumandan

    2009-01-01

    design parameters of probability of detection (Pd and probability of false alarm (Pfa. An optimum detector based on Estimator-Correlator (EC is developed, and its performance is compared with that of suboptimal Equal-Gain (EG combiner in different channel correlation scenarios. It is shown that in moderate channel correlation scenarios the detection performance of EC and EG is identical. The sensitivity of the proposed method to knowledge of motion parameters is also investigated. An extensive set of measurements based on CDMA-2000 pilot signals using the static antenna and synthetic array are used to experimentally verify these theoretical findings.

  6. Liquid sodium flow rate measurement by means of fluctuating signal cross correlation

    International Nuclear Information System (INIS)

    Zbinden, M.; Dutilleul, M.; Rastoix, M.

    1985-01-01

    Liquid sodium flow rate measurement by means of transit time calculation is a method whose development could be amplified by progresses in design of digital correlators. Transit time between two sensors separated by a known distance is measured with a cross correlation of two flow-dependant fluctuations and is generally estimated by the maximum of the correlation function. In the study discussed below one used signals provided by either thermocouples or electromagnetic flowmeters. This work has been done at the LISOR laboratory (Laboratoire d'Instrumentation Sodium des Renardieres) [fr

  7. Method and apparatus for a single channel digital communications system. [synchronization of received PCM signal by digital correlation with reference signal

    Science.gov (United States)

    Couvillon, L. A., Jr.; Carl, C.; Goldstein, R. M.; Posner, E. C.; Green, R. R. (Inventor)

    1973-01-01

    A method and apparatus are described for synchronizing a received PCM communications signal without requiring a separate synchronizing channel. The technique provides digital correlation of the received signal with a reference signal, first with its unmodulated subcarrier and then with a bit sync code modulated subcarrier, where the code sequence length is equal in duration to each data bit.

  8. Adaptive endpoint detection of seismic signal based on auto-correlated function

    International Nuclear Information System (INIS)

    Fan Wanchun; Shi Ren

    2000-01-01

    There are certain shortcomings for the endpoint detection by time-waveform envelope and/or by checking the travel table (both labelled as the artificial detection method). Based on the analysis of the auto-correlation function, the notion of the distance between auto-correlation functions was quoted, and the characterizations of the noise and the signal with noise were discussed by using the distance. Then, the method of auto-adaptable endpoint detection of seismic signal based on auto-correlated similarity was summed up. The steps of implementation and determining of the thresholds were presented in detail. The experimental results that were compared with the methods based on artificial detecting show that this method has higher sensitivity even in a low SNR circumstance

  9. Photoplethysmogram signal quality estimation using repeated Gaussian filters and cross-correlation

    International Nuclear Information System (INIS)

    Karlen, W; Kobayashi, K; Dumont, G A; Ansermino, J M

    2012-01-01

    Pulse oximeters are monitors that noninvasively measure heart rate and blood oxygen saturation (SpO 2 ). Unfortunately, pulse oximetry is prone to artifacts which negatively impact the accuracy of the measurement and can cause a significant number of false alarms. We have developed an algorithm to segment pulse oximetry signals into pulses and estimate the signal quality in real time. The algorithm iteratively calculates a signal quality index (SQI) ranging from 0 to 100. In the presence of artifacts and irregular signal morphology, the algorithm outputs a low SQI number. The pulse segmentation algorithm uses the derivative of the signal to find pulse slopes and an adaptive set of repeated Gaussian filters to select the correct slopes. Cross-correlation of consecutive pulse segments is used to estimate signal quality. Experimental results using two different benchmark data sets showed a good pulse detection rate with a sensitivity of 96.21% and a positive predictive value of 99.22%, which was equivalent to the available reference algorithm. The novel SQI algorithm was effective and produced significantly lower SQI values in the presence of artifacts compared to SQI values during clean signals. The SQI algorithm may help to guide untrained pulse oximeter users and also help in the design of advanced algorithms for generating smart alarms. (paper)

  10. Photoplethysmogram signal quality estimation using repeated Gaussian filters and cross-correlation.

    Science.gov (United States)

    Karlen, W; Kobayashi, K; Ansermino, J M; Dumont, G A

    2012-10-01

    Pulse oximeters are monitors that noninvasively measure heart rate and blood oxygen saturation (SpO2). Unfortunately, pulse oximetry is prone to artifacts which negatively impact the accuracy of the measurement and can cause a significant number of false alarms. We have developed an algorithm to segment pulse oximetry signals into pulses and estimate the signal quality in real time. The algorithm iteratively calculates a signal quality index (SQI) ranging from 0 to 100. In the presence of artifacts and irregular signal morphology, the algorithm outputs a low SQI number. The pulse segmentation algorithm uses the derivative of the signal to find pulse slopes and an adaptive set of repeated Gaussian filters to select the correct slopes. Cross-correlation of consecutive pulse segments is used to estimate signal quality. Experimental results using two different benchmark data sets showed a good pulse detection rate with a sensitivity of 96.21% and a positive predictive value of 99.22%, which was equivalent to the available reference algorithm. The novel SQI algorithm was effective and produced significantly lower SQI values in the presence of artifacts compared to SQI values during clean signals. The SQI algorithm may help to guide untrained pulse oximeter users and also help in the design of advanced algorithms for generating smart alarms.

  11. Muscle MRI STIR signal intensity and atrophy are correlated to focal lower limb neuropathy severity

    Energy Technology Data Exchange (ETDEWEB)

    Deroide, N.; Mambre, L.; Kubis, Nathalie [Service de Physiologie Clinique-Explorations Fonctionnelles, AP-HP, Hopital Lariboisiere, Paris (France); Universite Paris Diderot, Sorbonne Paris Cite France, Paris (France); Bousson, V.; Laredo, J.D. [Universite Paris Diderot, Sorbonne Paris Cite France, Paris (France); Radiologie Osteo-articulaire, AP-HP, Hopital Lariboisiere, Paris (France); Vicaut, E. [Universite Paris Diderot, Sorbonne Paris Cite France, Paris (France); URC, AP-HP, Hopital Lariboisiere, Paris (France)

    2014-09-26

    The objective is to determine if muscle MRI is useful for assessing neuropathy severity. Clinical, MRI and electromyography (EMG) examinations were performed in 17 patients with focal lower limb neuropathies. MRI Short Tau Inversion Recovery (STIR) signal intensity, amyotrophy, and muscle fatty infiltration measured after T1-weighted image acquisition, EMG spontaneous activity (SA), and maximal voluntary contraction (MVC) were graded using semiquantitative scores and quantitative scores for STIR signal intensity and were correlated to the Medical Research Council (MRC) score for testing muscle strength. Within this population, subgroups were selected according to severity (mild versus severe), duration (subacute versus chronic), and topography (distal versus proximal) of the neuropathy. EMG SA and MVC MRI amyotrophy and quantitative scoring of muscle STIR intensity were correlated with the MRC score. Moreover, MRI amyotrophy was significantly increased in severe, chronic, and proximal neuropathies along with fatty infiltration in chronic lesions. Muscle MRI atrophy and quantitative evaluation of signal intensity were correlated to MRC score in our study. Semiquantitative evaluation of muscle STIR signal was sensitive enough for detection of topography of the nerve lesion but was not suitable to assess severity. Muscle MRI could support EMG in chronic and proximal neuropathy, which showed poor sensitivity in these patients. (orig.)

  12. Zero-error classical channel capacity and simulation cost assisted by quantum non-signalling correlations

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Andreas [Universitat Autonoma de Barcelona (Spain)

    2014-07-01

    We describe quantum non-signalling correlations as two-input and two-output completely positive and trace preserving maps with linear constraints determining non-signalling. We then study the one-shot zero-error classical capacity of a quantum channel assisted by quantum non-signalling correlations, and the reverse problem of simulation. Both lead to simple semidefinite programmings (SDPs) whose solutions can be given in terms of the conditional min-entropies and depend only on the Kraus operator space of the channel. In particular, we show that the asymptotic zero-error classical simulation cost is precisely the conditional min-entropy of the Choi-Jamiolkowski matrix of the given channel. The asymptotic zero-error classical capacity is given by the regularization of a sequence of SDPs, and generally has no simple form. Interestingly, for the class of classical-quantum channels, we show that the asymptotic capacity is reduced to the solution of a rather simple SDP, which coincides with a quantum version of the fractional packing number suggested by Aram Harrow. This further gives an operational interpretation of the celebrated Lovasz number of a classical graph as the zero-error classical capacity of the graph assisted by quantum non-signalling correlations.

  13. Analysis of cross-correlations in electroencephalogram signals as an approach to proactive diagnosis of schizophrenia

    Science.gov (United States)

    Timashev, Serge F.; Panischev, Oleg Yu.; Polyakov, Yuriy S.; Demin, Sergey A.; Kaplan, Alexander Ya.

    2012-02-01

    We apply flicker-noise spectroscopy (FNS), a time series analysis method operating on structure functions and power spectrum estimates, to study the clinical electroencephalogram (EEG) signals recorded in children/adolescents (11 to 14 years of age) with diagnosed schizophrenia-spectrum symptoms at the National Center for Psychiatric Health (NCPH) of the Russian Academy of Medical Sciences. The EEG signals for these subjects were compared with the signals for a control sample of chronically depressed children/adolescents. The purpose of the study is to look for diagnostic signs of subjects' susceptibility to schizophrenia in the FNS parameters for specific electrodes and cross-correlations between the signals simultaneously measured at different points on the scalp. Our analysis of EEG signals from scalp-mounted electrodes at locations F3 and F4, which are symmetrically positioned in the left and right frontal areas of cerebral cortex, respectively, demonstrates an essential role of frequency-phase synchronization, a phenomenon representing specific correlations between the characteristic frequencies and phases of excitations in the brain. We introduce quantitative measures of frequency-phase synchronization and systematize the values of FNS parameters for the EEG data. The comparison of our results with the medical diagnoses for 84 subjects performed at NCPH makes it possible to group the EEG signals into 4 categories corresponding to different risk levels of subjects' susceptibility to schizophrenia. We suggest that the introduced quantitative characteristics and classification of cross-correlations may be used for the diagnosis of schizophrenia at the early stages of its development.

  14. Correlation Between Electromagnetic Signals and Seismic Events on Central Colombia Region to Establish Seismic Precursors Existence

    Science.gov (United States)

    Caneva, A.; Vargas Jiménez, C. A.; Solano Fino, J. M.

    2017-12-01

    It was already shown by several authors around the world some kinds of correlation between electric and magnetic signals and seismic events looking for precursors to the last ones emitted from the seismic source. This investigation tends to establish a correlation between electro-magnetic (EM) signals on the ground surface and seismic events on the Colombian lithospheric system. The events correlation was made with data from the Seismological Network of the Sabana de Bogotá (RSSB for its acronym in Spanish), a temporal seismological network on Chichimene (Acacías, Meta, Colombia) and the National Seismological Network of Colombia (RSNC, for its acronym in Spanish). The project involved the design, construction and preliminary tests for the necessary instruments added to the RSSB as multi-parameter stations with seismic broadband, electric polarizing and non-polarizing dipoles and Earth's magnetic field sensors. Correlations were made considering time, frequency and `natural time' domains with filtering and preprocessing algorithms. Among the main results are the almost complete lack of electric disturbances known as Seismic Electric Signals (SES) and very few of the magnetic kind. However, another kind of long period magnetic disturbances for some stations and events where found. More instruments have to be deployed in order to get a better understanding of these disturbances and develop a robust model.

  15. Real-Time EEG Signal Enhancement Using Canonical Correlation Analysis and Gaussian Mixture Clustering

    Directory of Open Access Journals (Sweden)

    Chin-Teng Lin

    2018-01-01

    Full Text Available Electroencephalogram (EEG signals are usually contaminated with various artifacts, such as signal associated with muscle activity, eye movement, and body motion, which have a noncerebral origin. The amplitude of such artifacts is larger than that of the electrical activity of the brain, so they mask the cortical signals of interest, resulting in biased analysis and interpretation. Several blind source separation methods have been developed to remove artifacts from the EEG recordings. However, the iterative process for measuring separation within multichannel recordings is computationally intractable. Moreover, manually excluding the artifact components requires a time-consuming offline process. This work proposes a real-time artifact removal algorithm that is based on canonical correlation analysis (CCA, feature extraction, and the Gaussian mixture model (GMM to improve the quality of EEG signals. The CCA was used to decompose EEG signals into components followed by feature extraction to extract representative features and GMM to cluster these features into groups to recognize and remove artifacts. The feasibility of the proposed algorithm was demonstrated by effectively removing artifacts caused by blinks, head/body movement, and chewing from EEG recordings while preserving the temporal and spectral characteristics of the signals that are important to cognitive research.

  16. Dynamic spectro-polarimeter based on a modified Michelson interferometric scheme.

    Science.gov (United States)

    Dembele, Vamara; Jin, Moonseob; Baek, Byung-Joon; Kim, Daesuk

    2016-06-27

    A simple dynamic spectro-polarimeter based on a modified Michelson interferometric scheme is described. The proposed system can extract a spectral Stokes vector of a transmissive anisotropic object. Detail theoretical background is derived and experiments are conducted to verify the feasibility of the proposed novel snapshot spectro-polarimeter. The proposed dynamic spectro-polarimeter enables us to extract highly accurate spectral Stokes vector of any transmissive anisotropic object with a frame rate of more than 20Hz.

  17. Correlation between laser-induced breakdown spectroscopy signal and moisture content

    International Nuclear Information System (INIS)

    Liu, Yuan; Gigant, Lionel; Baudelet, Matthieu; Richardson, Martin

    2012-01-01

    The possibility of using Laser-Induced Breakdown Spectroscopy (LIBS) for measuring the moisture content of fresh food samples is studied. The normalized line emission of oxygen is highly correlated with the moisture content of the sample, cheese in our case, and can be used as a moisture marker in situations where oxygen interference from the matrix is not a critical issue. The linear correlation between the oxygen signal and the moisture content in the sample shows great potential for using LIBS as an alternative spectroscopic method for moisture monitoring. - Highlights: ► Quantitative moisture measurement by LIBS. ► Use of matrix effects and normalization for physical information on the sample. ► Use of signal from oxygen and CN radical in air background for moisture measurement.

  18. Correlated and uncorrelated invisible temporal white noise alters mesopic rod signaling.

    Science.gov (United States)

    Hathibelagal, Amithavikram R; Feigl, Beatrix; Kremers, Jan; Zele, Andrew J

    2016-03-01

    We determined how rod signaling at mesopic light levels is altered by extrinsic temporal white noise that is correlated or uncorrelated with the activity of one (magnocellular, parvocellular, or koniocellular) postreceptoral pathway. Rod and cone photoreceptor excitations were independently controlled using a four-primary photostimulator. Psychometric (Weibull) functions were measured for incremental rod pulses (50 to 250 ms) in the presence (or absence; control) of perceptually invisible subthreshold extrinsic noise. Uncorrelated (rod) noise facilitates rod detection. Correlated postreceptoral pathway noise produces differential changes in rod detection thresholds and decreases the slope of the psychometric functions. We demonstrate that invisible extrinsic noise changes rod-signaling characteristics within the three retinogeniculate pathways at mesopic illumination depending on the temporal profile of the rod stimulus and the extrinsic noise type.

  19. Correlation between laser-induced breakdown spectroscopy signal and moisture content

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuan [Townes Laser Institute, CREOL - The College of Optics and Photonics, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816 (United States); Gigant, Lionel [Townes Laser Institute, CREOL - The College of Optics and Photonics, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816 (United States); Universite Bordeaux 1, 351 cours de la Liberation 33405 Talence Cedex (France); Baudelet, Matthieu, E-mail: baudelet@creol.ucf.edu [Townes Laser Institute, CREOL - The College of Optics and Photonics, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816 (United States); Richardson, Martin [Townes Laser Institute, CREOL - The College of Optics and Photonics, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816 (United States)

    2012-07-15

    The possibility of using Laser-Induced Breakdown Spectroscopy (LIBS) for measuring the moisture content of fresh food samples is studied. The normalized line emission of oxygen is highly correlated with the moisture content of the sample, cheese in our case, and can be used as a moisture marker in situations where oxygen interference from the matrix is not a critical issue. The linear correlation between the oxygen signal and the moisture content in the sample shows great potential for using LIBS as an alternative spectroscopic method for moisture monitoring. - Highlights: Black-Right-Pointing-Pointer Quantitative moisture measurement by LIBS. Black-Right-Pointing-Pointer Use of matrix effects and normalization for physical information on the sample. Black-Right-Pointing-Pointer Use of signal from oxygen and CN radical in air background for moisture measurement.

  20. Full-field wrist pulse signal acquisition and analysis by 3D Digital Image Correlation

    Science.gov (United States)

    Xue, Yuan; Su, Yong; Zhang, Chi; Xu, Xiaohai; Gao, Zeren; Wu, Shangquan; Zhang, Qingchuan; Wu, Xiaoping

    2017-11-01

    Pulse diagnosis is an essential part in four basic diagnostic methods (inspection, listening, inquiring and palpation) in traditional Chinese medicine, which depends on longtime training and rich experience, so computerized pulse acquisition has been proposed and studied to ensure the objectivity. To imitate the process that doctors using three fingertips with different pressures to feel fluctuations in certain areas containing three acupoints, we established a five dimensional pulse signal acquisition system adopting a non-contacting optical metrology method, 3D digital image correlation, to record the full-field displacements of skin fluctuations under different pressures. The system realizes real-time full-field vibration mode observation with 10 FPS. The maximum sample frequency is 472 Hz for detailed post-processing. After acquisition, the signals are analyzed according to the amplitude, pressure, and pulse wave velocity. The proposed system provides a novel optical approach for digitalizing pulse diagnosis and massive pulse signal data acquisition for various types of patients.

  1. An upgraded interferometer-polarimeter system for broadband fluctuation measurements

    International Nuclear Information System (INIS)

    Parke, E.; Ding, W. X.; Brower, D. L.; Duff, J.

    2016-01-01

    Measuring high-frequency fluctuations (above tearing mode frequencies) is important for diagnosing instabilities and transport phenomena. The Madison Symmetric Torus interferometer-polarimeter system has been upgraded to utilize improved planar-diode mixer technology. The new mixers reduce phase noise and allow more sensitive measurements of fluctuations at high frequency. Typical polarimeter rms phase noise values of 0.05°–0.07° are obtained with 400 kHz bandwidth. The low phase noise enables the resolution of fluctuations up to 250 kHz for polarimetry and 600 kHz for interferometry. The importance of probe beam alignment for polarimetry is also verified; previously reported tolerances of ≤0.1 mm displacement for equilibrium and tearing mode measurements minimize contamination due to spatial misalignment to within acceptable levels for chords near the magnetic axis.

  2. An upgraded interferometer-polarimeter system for broadband fluctuation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Parke, E., E-mail: eparke@ucla.edu; Ding, W. X.; Brower, D. L. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States); Duff, J. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2016-11-15

    Measuring high-frequency fluctuations (above tearing mode frequencies) is important for diagnosing instabilities and transport phenomena. The Madison Symmetric Torus interferometer-polarimeter system has been upgraded to utilize improved planar-diode mixer technology. The new mixers reduce phase noise and allow more sensitive measurements of fluctuations at high frequency. Typical polarimeter rms phase noise values of 0.05°–0.07° are obtained with 400 kHz bandwidth. The low phase noise enables the resolution of fluctuations up to 250 kHz for polarimetry and 600 kHz for interferometry. The importance of probe beam alignment for polarimetry is also verified; previously reported tolerances of ≤0.1 mm displacement for equilibrium and tearing mode measurements minimize contamination due to spatial misalignment to within acceptable levels for chords near the magnetic axis.

  3. Single image super-resolution via regularized extreme learning regression for imagery from microgrid polarimeters

    Science.gov (United States)

    Sargent, Garrett C.; Ratliff, Bradley M.; Asari, Vijayan K.

    2017-08-01

    The advantage of division of focal plane imaging polarimeters is their ability to obtain temporally synchronized intensity measurements across a scene; however, they sacrifice spatial resolution in doing so due to their spatially modulated arrangement of the pixel-to-pixel polarizers and often result in aliased imagery. Here, we propose a super-resolution method based upon two previously trained extreme learning machines (ELM) that attempt to recover missing high frequency and low frequency content beyond the spatial resolution of the sensor. This method yields a computationally fast and simple way of recovering lost high and low frequency content from demosaicing raw microgrid polarimetric imagery. The proposed method outperforms other state-of-the-art single-image super-resolution algorithms in terms of structural similarity and peak signal-to-noise ratio.

  4. A Detection Algorithm for the BOC Signal Based on Quadrature Channel Correlation

    Directory of Open Access Journals (Sweden)

    Bo Qian

    2018-01-01

    Full Text Available In order to solve the problem of detecting a BOC signal, which uses a long-period pseudo random sequence, an algorithm is presented based on quadrature channel correlation. The quadrature channel correlation method eliminates the autocorrelation component of the carrier wave, allowing for the extraction of the absolute autocorrelation peaks of the BOC sequence. If the same lag difference and height difference exist for the adjacent peaks, the BOC signal can be detected effectively using a statistical analysis of the multiple autocorrelation peaks. The simulation results show that the interference of the carrier wave component is eliminated and the autocorrelation peaks of the BOC sequence are obtained effectively without demodulation. The BOC signal can be detected effectively when the SNR is greater than −12 dB. The detection ability can be improved further by increasing the number of sampling points. The higher the ratio of the square wave subcarrier speed to the pseudo random sequence speed is, the greater the detection ability is with a lower SNR. The algorithm presented in this paper is superior to the algorithm based on the spectral correlation.

  5. PHYSICS WITH A FOCAL PLANE PROTON POLARIMETER FOR HALL A AT CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Ron Gilman; F.T. Baker; Louis Bimbot; Ed Brash; Charles Glashausser; Mark Jones; Gerfried Kumbartzki; Sirish Nanda; Charles F. Perdrisat; Vina Punjabi; Ronald Ransome; Paul Rutt

    1994-09-01

    A focal plane polarimeter intended for the CEBAF Hall A high resolution hadron spectrometer is under construction at Rutgers University and the College of William and Mary. Experiments with focal plane polarimeters are only now beginning at electron accelerators; they play a prominent role in the list of approved experiments for Hall A. Construction of the polarimeter is in progress, it is expected to be brought to CEBAF in spring 1995. Several coincidence (e,e'p) and singles (gamma, p) measurements by the Hall A Collaboration are expected to start in 1996. In this paper we describe the polarimeter and the physics program planned for it.

  6. The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    Science.gov (United States)

    Ishikawa, Shin-nosuke; Kano, R.; Kobayashi, K.; Bando, T.; Narukage, N..; Ishikawa, R.; Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Hara, H.; hide

    2014-01-01

    To Understand energy release process in the Sun including solar flares, it is essentially important to measure the magnetic field of the atmosphere of the Sun. Magnetic field measurement of the upper layers (upper chromosphere and above) was technically difficult and not well investigated yet. Upper chromosphere and transition region magnetic field measurement by Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) sounding rocket to be launched in 2015. The proposal is already selected and developments of the flight components are going.

  7. Use of the Far Infrared Tangential Interferometer/Polarimeter diagnostic for the study of rf driven plasma waves on NSTX.

    Science.gov (United States)

    Kim, J; Lee, K C; Kaita, R; Phillips, C K; Domier, C W; Valeo, E; Luhmann, N C; Bonoli, P T; Park, H

    2010-10-01

    A rf detection system for waves in the 30 MHz range has been constructed for the Far Infrared Tangential Interferometer/Polarimeter on National Spherical Torus Experiment (NSTX). It is aimed at monitoring high frequency density fluctuations driven by 30 MHz high harmonic fast wave fields. The levels of density fluctuations at various radial chords and antenna phase angles can be estimated using the electric field calculated by TORIC code and linearized continuity equation for the electron density. In this paper, the experimental arrangement for the detection of rf signal and preliminary results of simulation will be discussed.

  8. Automatic detection of noisy channels in fNIRS signal based on correlation analysis.

    Science.gov (United States)

    Guerrero-Mosquera, Carlos; Borragán, Guillermo; Peigneux, Philippe

    2016-09-15

    fNIRS signals can be contaminated by distinct sources of noise. While most of the noise can be corrected using digital filters, optimized experimental paradigms or pre-processing methods, few approaches focus on the automatic detection of noisy channels. In the present study, we propose a new method that detect automatically noisy fNIRS channels by combining the global correlations of the signal obtained from sliding windows (Cui et al., 2010) with correlation coefficients extracted experimental conditions defined by triggers. The validity of the method was evaluated on test data from 17 participants, for a total of 16 NIRS channels per subject, positioned over frontal, dorsolateral prefrontal, parietal and occipital areas. Additionally, the detection of noisy channels was tested in the context of different levels of cognitive requirement in a working memory N-back paradigm. Bad channels detection accuracy, defined as the proportion of bad NIRS channels correctly detected among the total number of channels examined, was close to 91%. Under different cognitive conditions the area under the Receiver Operating Curve (AUC) increased from 60.5% (global correlations) to 91.2% (local correlations). Our results show that global correlations are insufficient for detecting potentially noisy channels when the whole data signal is included in the analysis. In contrast, adding specific local information inherent to the experimental paradigm (e.g., cognitive conditions in a block or event-related design), improved detection performance for noisy channels. Also, we show that automated fNIRS channel detection can be achieved with high accuracy at low computational cost. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. The Polarimeter for Relativistic Astrophysical X-ray Sources

    Science.gov (United States)

    Jahoda, Keith; Kallman, Timothy R.; Kouveliotou, Chryssa; Angelini, Lorella; Black, J. Kevin; Hill, Joanne E.; Jaeger, Theodore; Kaaret, Philip E.; Markwardt, Craig B.; Okajima, Takashi; Petre, Robert; Schnittman, Jeremy; Soong, Yang; Strohmayer, Tod E.; Tamagawa, Toru; Tawara, Yuzuru

    2016-07-01

    The Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) is one of three Small Explorer (SMEX) missions selected by NASA for Phase A study, with a launch date in 2020. The PRAXyS Observatory exploits grazing incidence X-ray mirrors and Time Projection Chamber Polarimeters capable of measuring the linear polarization of cosmic X-ray sources in the 2-10 keV band. PRAXyS combines well-characterized instruments with spacecraft rotation to ensure low systematic errors. The PRAXyS payload is developed at the Goddard Space Flight Center with the Johns Hopkins University Applied Physics Laboratory, University of Iowa, and RIKEN (JAXA) collaborating on the Polarimeter Assembly. The LEOStar-2 spacecraft bus is developed by Orbital ATK, which also supplies the extendable optical bench that enables the Observatory to be compatible with a Pegasus class launch vehicle. A nine month primary mission will provide sensitive observations of multiple black hole and neutron star sources, where theory predicts polarization is a strong diagnostic, as well as exploratory observations of other high energy sources. The primary mission data will be released to the community rapidly and a Guest Observer extended mission will be vigorously proposed.

  10. X-Ray Spectro-Polarimetry with Photoelectric Polarimeters

    Science.gov (United States)

    Strohmayer, T. E.

    2017-01-01

    We derive a generalization of forward fitting for X-ray spectroscopy to include linear polarization of X-ray sources, appropriate for the anticipated next generation of space-based photoelectric polarimeters. We show that the inclusion of polarization sensitivity requires joint fitting to three observed spectra, one for each of the Stokes parameters, I(E), U(E), and Q(E). The equations for StokesI (E) (the total intensity spectrum) are identical to the familiar case with no polarization sensitivity, and for which the model-predicted spectrum is obtained by a convolution of the source spectrum, F (E), with the familiar energy response function,(E) R(E,E), where (E) and R(E,E) are the effective area and energy redistribution matrix, respectively. In addition to the energy spectrum, the two new relations for U(E) and Q(E) include the source polarization fraction and position angle versus energy, a(E), and 0(E), respectively, and the model-predicted spectra for these relations are obtained by a convolution with the modulated energy response function, (E)(E) R(E,E), where(E) is the energy-dependent modulation fraction that quantifies a polarimeters angular response to 100 polarized radiation. We present results of simulations with response parameters appropriate for the proposed PRAXyS Small Explorer observatory to illustrate the procedures and methods, and we discuss some aspects of photoelectric polarimeters with relevance to understanding their calibration and operation.

  11. Frequency averaging of fluctuations in the cross-correlation reception of noiselike signals reflected from a rough sea surface

    Science.gov (United States)

    Baranov, V. F.; Gerasimova, T. I.; Gulin, É. P.

    2007-04-01

    For noiselike signals reflected from a rough sea surface and received by a correlation receiver, the effect achieved at the receiver output as a result of frequency averaging of signal fluctuations is considered. Expressions characterizing the effect of frequency averaging are derived by using the generalized two-scale model describing the frequency correlation of strong fluctuations of the transfer function. Results of numerical calculations for the variance of fluctuations at the output of the correlation receiver are presented for different relative values of the frequency bandwidth of noiselike signals and the frequency correlation scales for the cases of both weak and strong fluctuations.

  12. Correlation dynamics and enhanced signals for the identification of serial biomolecules and DNA bases

    International Nuclear Information System (INIS)

    Ahmed, Towfiq; Haraldsen, Jason T; Balatsky, Alexander V; Rehr, John J; Di Ventra, Massimiliano; Schuller, Ivan

    2014-01-01

    Nanopore-based sequencing has demonstrated a significant potential for the development of fast, accurate, and cost-efficient fingerprinting techniques for next generation molecular detection and sequencing. We propose a specific multilayered graphene-based nanopore device architecture for the recognition of single biomolecules. Molecular detection and analysis can be accomplished through the detection of transverse currents as the molecule or DNA base translocates through the nanopore. To increase the overall signal-to-noise ratio and the accuracy, we implement a new ‘multi-point cross-correlation’ technique for identification of DNA bases or other molecules on the single molecular level. We demonstrate that the cross-correlations between each nanopore will greatly enhance the transverse current signal for each molecule. We implement first-principles transport calculations for DNA bases surveyed across a multilayered graphene nanopore system to illustrate the advantages of the proposed geometry. A time-series analysis of the cross-correlation functions illustrates the potential of this method for enhancing the signal-to-noise ratio. This work constitutes a significant step forward in facilitating fingerprinting of single biomolecules using solid state technology. (paper)

  13. Correlation dynamics and enhanced signals for the identification of serial biomolecules and DNA bases

    Science.gov (United States)

    Ahmed, Towfiq; Haraldsen, Jason T.; Rehr, John J.; Di Ventra, Massimiliano; Schuller, Ivan; Balatsky, Alexander V.

    2014-03-01

    Nanopore-based sequencing has demonstrated a significant potential for the development of fast, accurate, and cost-efficient fingerprinting techniques for next generation molecular detection and sequencing. We propose a specific multilayered graphene-based nanopore device architecture for the recognition of single biomolecules. Molecular detection and analysis can be accomplished through the detection of transverse currents as the molecule or DNA base translocates through the nanopore. To increase the overall signal-to-noise ratio and the accuracy, we implement a new ‘multi-point cross-correlation’ technique for identification of DNA bases or other molecules on the single molecular level. We demonstrate that the cross-correlations between each nanopore will greatly enhance the transverse current signal for each molecule. We implement first-principles transport calculations for DNA bases surveyed across a multilayered graphene nanopore system to illustrate the advantages of the proposed geometry. A time-series analysis of the cross-correlation functions illustrates the potential of this method for enhancing the signal-to-noise ratio. This work constitutes a significant step forward in facilitating fingerprinting of single biomolecules using solid state technology.

  14. Mechanomyography signals in spastic muscle and the correlation with the modified Ashworth scale.

    Science.gov (United States)

    Santos, E L; Santos, M C; Krueger, E; Nogueira-Neto, G N; Nohama, P

    2016-08-01

    The modified Ashworth scale (MAS) is the most widely used measurement technique to assess levels of spasticity. In MAS, the evaluator graduates spasticity considering his/her subjective analysis of the muscular endurance during passive stretching. Therefore, it is a subjective scale. Mechanomyography (MMG) allows registering the vibrations generated by muscle contraction and stretching events that propagate through the tissue until the surface of the skin. With this in mind, this study aimed to investigate possible correlations between MMG signal and muscle spasticity levels determined by MAS. We evaluated 34 limbs considered spastic by MAS, including upper and lower limbs of 22 individuals of both sexes. Simultaneously, the MMG signals of the spastic muscle group (agonists) were acquired. The features investigated involved, in the time domain, the median energy (MMGME) of the MMG Z-axis (perpendicular to the muscle fibers) and, in the frequency domain, the median frequency (MMG mf ). The Kruskal-Wallis test (p<;0.001) determined that there were significant differences between intergroup MAS spasticity levels for MMG me . There was a high linear correlation between the MMG me and MAS (R 2 =0.9557) and also a high correlation as indicated by Spearman test (ρ=0.9856; p<;0.001). In spectral analysis, the Kruskal-Wallis test (p = 0.0059) showed that MMG mf did not present significant differences between MAS spasticity levels. There was moderate linear correlation between MAS and MMG mf (R 2 =0.4883 and Spearman test [ρ = 0.4590; p <; 0.001]). Between the two investigated features, we conclude that the median energy is the most viable feature to evaluate spasticity due to strong correlations with the MAS.

  15. Modified Multilook Cross Correlation technique for Doppler centroid estimation in SAR image signal processing

    Science.gov (United States)

    Bee Cheng, Sew

    Synthetic Aperture Radar (SAR) is one of the widely used remote sensing sensors which produces high resolution image by using advance signal processing technique. SAR managed to operate in all sorts of weather and cover wide range of area. To produce a high-quality image, accurate parameters such as Doppler centroid are required for precise SAR signal processing. In the azimuth matched filtering of SAR signal processing, Doppler centroid is an important azimuth parameter that helps to focus the image pixels. Doppler centroid has always been overlooked during SAR signal processing. It is due to the fact that estimation of Doppler centroid involved complicated calculation and increased computational load. Therefore, researcher used to apply only the approximate Doppler value which is not precise and cause defocus effort in the generated SAR image. In this study, several conventional Doppler centroid estimation algorithms are reviewed and developed using Matlab software program to extract the Doppler parameter from received SAR data, namely Spectrum Fit Algorithm, Wavelength Diversity Algorithm (WDA), Multilook Cross Correlation Algorithm (MLCC), and Multilook Beat Frequency Algorithm (MLBF). Two sets of SAR data are employed to evaluate the performance of each estimator, i.e. simulated point target data and RADARSAT-1 Vancouver scene raw data. These experiments gave a sense of accuracy for the estimated results together with computational time consumption. Point target is simulated to generate ideal case SAR data with pre-defined SAR system parameters.

  16. Control mechanism to prevent correlated message arrivals from degrading signaling no. 7 network performance

    Science.gov (United States)

    Kosal, Haluk; Skoog, Ronald A.

    1994-04-01

    Signaling System No. 7 (SS7) is designed to provide a connection-less transfer of signaling messages of reasonable length. Customers having access to user signaling bearer capabilities as specified in the ANSI T1.623 and CCITT Q.931 standards can send bursts of correlated messages (e.g., by doing a file transfer that results in the segmentation of a block of data into a number of consecutive signaling messages) through SS7 networks. These message bursts with short interarrival times could have an adverse impact on the delay performance of the SS7 networks. A control mechanism, Credit Manager, is investigated in this paper to regulate incoming traffic to the SS7 network by imposing appropriate time separation between messages when the incoming stream is too bursty. The credit manager has a credit bank where credits accrue at a fixed rate up to a prespecified credit bank capacity. When a message arrives, the number of octets in that message is compared to the number of credits in the bank. If the number of credits is greater than or equal to the number of octets, then the message is accepted for transmission and the number of credits in the bank is decremented by the number of octets. If the number of credits is less than the number of octets, then the message is delayed until enough credits are accumulated. This paper presents simulation results showing delay performance of the SS7 ISUP and TCAP message traffic with a range of correlated message traffic, and control parameters of the credit manager (i.e., credit generation rate and bank capacity) are determined that ensure the traffic entering the SS7 network is acceptable. The results show that control parameters can be set so that for any incoming traffic stream there is no detrimental impact on the SS7 ISUP and TCAP message delay, and the credit manager accepts a wide range of traffic patterns without causing significant delay.

  17. A New Cost-Effective Diode Laser Polarimeter Apparatus Constructed by Undergraduate Students

    Science.gov (United States)

    Lisboa, Pedro; Sotomayor, Joo; Ribeiro, Paulo

    2010-01-01

    The construction of a diode laser polarimeter apparatus by undergraduate students is described. The construction of the modular apparatus by undergraduate students gives them an insight into how it works and how the measurement of a physical or chemical property is conducted. The students use the polarimeter to obtain rotation angle values for the…

  18. Calibration of a neutron polarimeter in the 0.2-1.1GeV region

    International Nuclear Information System (INIS)

    Semenov, A.Yu.; Zhang, W.M.; Madey, R.; Ahmidouch, A.; Anderson, B.D.; Assamagan, K.; Avery, S.; Baldwin, A.R.; Crowell, A.S.; Eden, T.; Manley, D.M.; Markowitz, P.; Milleret, G.; Prout, D.; Reichelt, T.; Semenova, I.A.; Ulmer, P.E.; Voutier, E.; Watson, J.W.; Wells, S.P.

    2006-01-01

    We measured the analyzing power and the efficiency of a neutron polarimeter at the Saturne National Laboratory in France with central energies of the neutron beam of 261,533,752,922, and 1057MeV. This polarimeter was a prototype designed to measure G E n , the neutron electric form factor, at the Thomas Jefferson National Accelerator Facility

  19. The 270 MeV deuteron beam polarimeter at the Nuclotron Internal Target Station

    Energy Technology Data Exchange (ETDEWEB)

    Kurilkin, P.K. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Moscow State Institute of Radio-engineering Electronics and Automation (Technical University), Moscow (Russian Federation); Ladygin, V.P., E-mail: vladygin@jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Moscow State Institute of Radio-engineering Electronics and Automation (Technical University), Moscow (Russian Federation); Uesaka, T. [Center for Nuclear Study, University of Tokyo, Tokyo 113-0033 (Japan); Suda, K. [RIKEN Nishina Center, Saitama (Japan); Gurchin, Yu.V.; Isupov, A.Yu. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Itoh, K. [Department of Physics, Saitama University, Saitama (Japan); Janek, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Physics Department, University of Zilina, 010 26 Zilina (Slovakia); Karachuk, J.-T. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Advanced Research Institute for Electrical Engineering, Bucharest (Romania); Kawabata, T. [Center for Nuclear Study, University of Tokyo, Tokyo 113-0033 (Japan); Khrenov, A.N.; Kiselev, A.S.; Kizka, V.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kliman, J. [Institute of Physics of Slovak Academy of Sciences, Bratislava (Slovakia); Krasnov, V.A.; Livanov, A.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Nuclear Research, Moscow (Russian Federation); Maeda, Y. [Kyushi University, Hakozaki (Japan); Malakhov, A.I. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Matousek, V.; Morhach, M. [Institute of Physics of Slovak Academy of Sciences, Bratislava (Slovakia)

    2011-06-21

    A deuteron beam polarimeter has been constructed at the Internal Target Station at the Nuclotron of JINR. The polarimeter is based on spin-asymmetry measurements in the d-p elastic scattering at large angles and the deuteron kinetic energy of 270 MeV. It allows to measure vector and tensor components of the deuteron beam polarization simultaneously.

  20. A Shoebox Polarimeter: An Inexpensive Analytical Tool for Teachers and Students

    Science.gov (United States)

    Mehta, Akash; Greenbowe, Thomas J.

    2011-01-01

    A polarimeter can determine the optical activity of an organic or inorganic compound by providing information about the optical rotation of plane-polarized light when transmitted through that compound. This "Journal" has reported various construction methods for polarimeters. We report a unique construction using a shoebox, recycled office…

  1. Correlating optical, microwave and thermal remote sensing signals with groundwater head measurement time series

    Science.gov (United States)

    Sutanudjaja, E. H.; de Jong, S.; van Geer, F.; Bierkens, M. F.

    2010-12-01

    Due to global climate change, population growth and an ever increasing demand for fresh water, monitoring groundwater changes over large areas becomes very important. Current groundwater monitoring still heavily depends on groundwater head data that are often not available for large parts of the non-western world. Consequently, groundwater assessment, especially for large areas comprising several aquifers and basins, is very complex and not very accurate. The main research question of this study is to check whether optical, microwave and thermal remote sensing signals carry information on groundwater levels. The advantage of remote sensing data is that it provides synoptic overview of semi-quantitative maps of surface properties, such as vegetation, surface temperature, and soil moisture signals, where we seek the relation with shallow groundwater tables. In this study, we analyze and compare groundwater head measurement data and various remote sensing signals. Our datasets comprise over 5000 groundwater head measurement points in the Rhine-Meuse basin. These groundwater head data are compared to the signals of soil moisture (AMSR-E and ERS), thermal (MODIS land surface temperature) and vegetation (MODIS NDVI, LAI and FPAR). We investigated the correlation among these variables by performing straightforward statistical analyses, such as scatter-plots, multiple regression techniques and analyses of temporal variability between the variables. Results show that particularly the soil moisture demonstrates significant relations with groundwater depth, specifically for shallow water table depths and areas with sparse vegetation. We argue that remote sensing signals should be considered as important information for groundwater assessment in data-poor environments.

  2. Lumber intervertebral disk; Correlation with the signal intensity of magnetic resonance imaging and the histological changes

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Ryusei; Takahashi, Sadao; Ando, Tadashi; Kumano, Kiyoshi; Hiranuma, Kenji; Kanazawa, Yousuke; Konishi, Seiji; Eguchi, Masanobu; Tanioka, Hisaya (KantoRosai Hospital, Kawasaki, Kanagawa (Japan))

    1989-11-01

    We studied to provide precise correlations between the intensity of MRI signals and the degenerative changes of the nucleus pulposes of the L4/5 intervertebral disk herniations. 23 cases with the L4/5 intervertebral disk herniations having surgical treatment were examined using Magnetom H 15 (1.5 tesla) with surface coil. The images were obtained with T2 images (long TR (1000{approx}1600 msec), TE (60{approx}90 msec)). The intensity was measured using FUJI densitometer FD 101 at the lumber vertebral body and the intervertebral disk. We calculated the L4/5 intervertebral disk degeneration ratio (determined by comparing the modified L4/5 MR signal intensity with the modified L2/3 MR signal itensity). Histological changes were examined in the cellular components of the nucleus pulposus (such as the number of the nucleus cells, nucleus cell nesting and HE stainability of the nucleus cell) and the matrics substance (such as fibrillation, hyaline degeneration and granular degeneration). Histochemical studies were performed using Scott's Method (AB-0.4 M MgCl{sub 2} Alcinophilia, AB-09 M, MgCl{sub 2} Alcinophilia) to investigate glycosaminoglycans of the nucleus pulposus. We compared the histological and histochemical changes with the MR L4/5 intervetebral disk degeneration ratio. The decreasing MRI signal intensity of the nucleous pulposus was (1) corresponded to the pathological changes such as the increasing number of the cell nesting, fibrillation and hyaline degeneration of the nucleus polposus. (2) corresponded to the decrease in the total glycosaminoglycans of the nucleus pulposus. (3) corresponded to the early stage of degeneration of the nucleus polposus, but in aging when all levels of intervertebral disk degeneration appeared, we could not know the degree of the disk degeneration from the signal intensity of MRI. (J.P.N.).

  3. Characterizing the Hertz-VPM Polarimeter

    Science.gov (United States)

    Krejny; Novak; Chuss; Voellmer; Moseley; Wollack; Benford; Stauguhn; Jackson; Loewenstein; hide

    2008-01-01

    We present preliminary results from engineering tests conducted at Northwestern U. and the Submillimeter Telescope Observatory (SMTO) on Mt. Graham, AZ. The VPM provides a new method for modulating incoming polarization signals, using small linear translations instead of rotational motion. Our dual grid-mirror design has several advantages over the currently favored technology, the half-wave plate. The VPM appears to successfully modulate submillimeter polarization, with high efficiencies and low instrumental polarization. We briefly discuss feasibility of use for air- and space-born applications.

  4. The level of CD147 expression correlates with cyclophilin-induced signalling and chemotaxis

    Directory of Open Access Journals (Sweden)

    Constant Stephanie

    2011-10-01

    Full Text Available Abstract Background Previous studies identified CD147 as the chemotactic receptor on inflammatory leukocytes for extracellular cyclophilins (eCyp. However, CD147 is not known to associate with signal transducing molecules, so other transmembrane proteins, such as proteoglycans, integrins, and CD98, were suggested as receptor or co-receptor for eCyp. CD147 is ubiquitously expressed on many cell types, but relationship between the level of CD147 expression and cellular responses to eCyp has never been analyzed. Given the role of eCyp in pathogenesis of many diseases, it is important to know whether cellular responses to eCyp are regulated at the level of CD147 expression. Results Here, we manipulated CD147 expression levels on HeLa cells using RNAi and investigated the signalling and chemotactic responses to eCypA. Both Erk activation and chemotaxis correlated with the level of CD147 expression, with cells exhibiting low level expression being practically unresponsive to eCypA. Conclusions Our results provide the first demonstration of a chemotactic response of HeLa cells to eCypA, establish a correlation between the level of CD147 expression and the magnitude of cellular responses to eCypA, and indicate that CD147 may be a limiting factor in the receptor complex determining cyclophilin-induced Erk activation and cell migration.

  5. LEAP - A Large Area GRB Polarimeter for the ISS

    Science.gov (United States)

    McConnell, Mark L.; Baring, Matthew G.; Bloser, Peter F.; Briggs, Michael Stephen; Connaughton, Valerie; Dwyer, Joseph; Gaskin, Jessica; Grove, J. Eric; Gunji, Shuichi; Hartmann, Dieter; Hayashida, Kiyoshi; Hill, Joanne E.; Kippen, R. Marc; Kishimoto, Shunji; Kishimoto, Yuji; Krizmanic, John F.; Lundman, Christoffer; Mattingly, David; McBreen, Sheila; Meegan, Charles A.; Mihara, Tatehiro; Nakamori, Takeshi; Pearce, Mark; Phlips, Bernard; Preece, Robert D.; Produit, Nicolas; Ryan, James M.; Ryde, Felix; Sakamoto, Takanori; Strickman, Mark Samuel; Sturner, Steven J.; Takahashi, Hiromitsu; Toma, Kenji; Vestrand, W. Thomas; Wilson-Hodge, Colleen A.; yatsu, Yoichi; Yonetoku, Daisuke; Zhang, Bing

    2017-08-01

    The LargE Area burst Polarimeter (LEAP) is a mission concept for a wide FOV Compton scatter polarimeter instrument that would be mounted as an external payload on the International Space Station (ISS) in 2022. It has recently been proposed as an astrophysics Mission of Opportunity (MoO), with the primary objective of measuring polarization of the prompt emission of Gamma Ray Bursts (GRBs). It will achieve its science objectives with a simple mission design that features a single instrument based entirely on well-established, flight-proven scintillator-photomultiplier tube (PMT) technologies. LEAP will provide GRB polarization measurements from 30-500 keV and GRB spectroscopy from 5 keV up to 5 MeV, and will self-sufficiently provide the source localization that is required for analysis of the polarization data. The instrument consists of 9 independent polarimeter modules and associated electronics. Each module is a 12 x 12 array of independent plastic and CsI(Tl) scintillator elements, each with individual PMT readout, to identify and measure Compton scatter events. It will provide coverage of GRB spectra over a range that includes most values of Ep. With a total geometric scintillator area of 5000 cm2, LEAP will provide a total effective area for polarization (double scatter) events of ~500 cm2. LEAP will trigger on >200 GRBs within its FOV during a two-year mission. At least 120 GRBs will have sufficient counts to enable localization with an error of MDP) better than 30%. If GRBs are polarized at levels >50%, as suggested by published results, LEAP will provide definitive polarization measurements on ~100 GRBs. These data will allow LEAP to differentiate between the intrinsic and geometric classes of GRB models and further distinguish between two geometric models at the 95% confidence level. Detailed time-resolved and/or energy-resolved studies will be conducted for the brightest GRBs.

  6. Correlation Between X-ray And Microwave (sz) Signals From The Warm-hot Intergalactic Medium

    Science.gov (United States)

    Galeazzi, Massimiliano; Gupta, A.; Huffenberger, K.; Ursino, E.

    2010-05-01

    A large fraction of the low redshift baryons is believed to reside in a warm-hot filamentary gas in the intergalactic medium (WHIM). In the past we have successfully used XMM-Newton data to identify and characterize the WHIM angular signature using the autocorrelation function [Galeazzi 2009, 695, 1127]. Using the output of large scale hydrodynamic simulations we have also investigated the correlation between low energy X-ray emission and SZ effect from WHIM filaments. The largest of the current SZ surveys (with the South Pole Telescope [Ruhl 2004, Proc. SPIE, 5498, 11] and the Atacama Cosmology Telescope [Kosowsky 2004, NAR 47, 939; 2006, NAR 50, 969]) are mapping hundreds of square degrees at arcminute resolution at bands in 100-300 GHz, and have started identifying clusters detected by their SZ signature alone [e.g. Staniszewski 2009, ApJ, 701,32; Hincks 2009, arXiv:0907.0461]. Although the bulk of the total luminosity in the SZ effect is associated with collapsed structures like clusters, our work indicates that a significant fraction comes from unbound objects, mostly from overdense regions, like the WHIM. Due to the unique emission mechanism, the X-ray and SZ correlation provides additional constraints on the structure of the intergalactic gas. Adopting an adiabatic, polytropic model the SZ signal goes as ne1.2, compared with the x-ray emission that goes roughly as ne2 (slightly modified by the cooling function). In this paper we will discuss the result of our investigation on the correlation between X-ray emission and SZ signals and the implications for current X-ray and SZ observatories. We will also present our preliminary applications using actual data.

  7. LYSO crystal testing for an EDM polarimeter

    Science.gov (United States)

    Müller, F.; Keshelashvili, I.; Mchedlishvili, D.; JEDI Collaboration

    2017-11-01

    Four detector modules, built from three different LYSO crystals and two different types of light sensors (PMTs and SiPM arrays), have been tested with a deuteron beam from 100 MeV - 270 MeV at the COSY accelerator facility for the srEDM project at the Forschungszentrum Jülich in Germany. The detector modules were arranged in a cluster hand mounted on a positioning table. The deuteron beam was targeted at the center of each individual crystal for data analysis. The signals were digitized using a 14 bit, 250 MS/s flash ADC. Further, the energy spectra were calibrated using the known beam energies from the accelerator. From the calibrated spectra, the energy resolution was calculated. A resolution of 3% for the low energies and down to 1% for the high energy of 270 MeV was achieved. A deuteron reconstruction efficiency of almost 100% for low energies and around 70% for high energies was achieved. The SiPM light sensor showed a very good performance and will be used for the next generation of detector modules.

  8. Investigating the time-correlation properties in self-potential signals recorded in a seismic area of Irpinia, southern Italy

    International Nuclear Information System (INIS)

    Telesca, Luciano; Balasco, Marianna; Lapenna, Vincenzo

    2007-01-01

    Recent studies have shown that many natural phenomena are characterized by temporal fluctuations with long-range power-law correlations, suggesting a fractal geometry of the underlying dynamical system. The presence of power-law correlations are detected in four time series of self-potential signals, measured in a seismic area of southern Italy, by means of the Detrended Fluctuation Analysis (DFA), a method that permits the detection of long-range correlations in nonstationary time series. Results show scaling behaviour for all the signals recorded, indicating the presence of fractal features expressing a long-term correlation quantified by the numerical value of the scaling exponents. Our findings suggest a possible correlation between the earthquakes occurred in the area investigated and the relative maxima/minima of the mean and the standard deviation of the scaling exponents. Furthermore, the normalized average and standard deviation curves for all the signals tend to converge in correspondence with an earthquake

  9. Design of an adaptable Stokes polarimeter for exploring chromospheric magnetism

    Science.gov (United States)

    Louis, Rohan E.; Bayanna, A. Raja; Socas Navarro, Héctor

    2017-10-01

    The chromosphere is a highly complex and dynamic layer of the Sun, that serves as a conduit for mass and energy supply between two, very distinct regions of the solar atmosphere, namely, the photosphere and corona. Inferring magnetic fields in the chromosphere, has thus become an important topic, that can be addressed with large-aperture solar telescopes to carry out highly sensitive polarimetric measurements. In this article, we present a design of a polarimeter for investigating the chromospheric magnetic field. The instrument consists of a number of lenses, two ferro-electric liquid crystals, a Wollaston prism, and a CCD camera. The optical design is similar to that of a commercial zoom lens which allows a variable f# while maintaining focus and aberrations well within the Airy disc. The optical design of the Adaptable ChRomOspheric POLarimeter (ACROPOL) makes use of off-the-shelf components and is described for the 70 cm Vacuum Tower Telescope and the 1.5 m GREGOR telescope at Observatorio del Teide, Tenerife, Spain. Our design shows that the optical train can be separated into two units where the first unit, consisting of a single lens, has to be changed while going from the VTT to the GREGOR configuration. We also discuss the tolerances within which, diffraction limited performance can be achieved with our design.

  10. Liquid Water Cloud Properties During the Polarimeter Definition Experiment (PODEX)

    Science.gov (United States)

    Alexandrov, Mikhail D.; Cairns, Brian; Wasilewski, Andrzei P.; Ackerman, Andrew S.; McGill, Matthew J.; Yorks, John E.; Hlavka, Dennis L.; Platnick, Steven; Arnold, George; Van Diedenhoven, Bastiaan; hide

    2015-01-01

    We present retrievals of water cloud properties from the measurements made by the Research Scanning Polarimeter (RSP) during the Polarimeter Definition Experiment (PODEX) held between January 14 and February 6, 2013. The RSP was onboard the high-altitude NASA ER-2 aircraft based at NASA Dryden Aircraft Operation Facility in Palmdale, California. The retrieved cloud characteristics include cloud optical thickness, effective radius and variance of cloud droplet size distribution derived using a parameter-fitting technique, as well as the complete droplet size distribution function obtained by means of Rainbow Fourier Transform. Multi-modal size distributions are decomposed into several modes and the respective effective radii and variances are computed. The methodology used to produce the retrieval dataset is illustrated on the examples of a marine stratocumulus deck off California coast and stratus/fog over California's Central Valley. In the latter case the observed bimodal droplet size distributions were attributed to two-layer cloud structure. All retrieval data are available online from NASA GISS website.

  11. SHARP: the SHARC-II polarimeter for CSO

    Science.gov (United States)

    Li, H.; Attard, M.; Dowell, C. D.; Hildebrand, R. H.; Houde, M.; Kirby, L.; Novak, G.; Vaillancourt, J. E.

    2006-06-01

    SHARC-II is a 32 × 12 pixel submillimeter camera that is used with the ten-meter diameter Caltech Submillimeter Observatory (CSO) on Mauna Kea. This camera can be operated at either 350 or 450 microns. We developed a module that is installed at the CSO Nasmyth focus in order to convert SHARC-II into a sensitive imaging polarimeter, which we refer to as "SHARP". SHARP splits the incident beam into two orthogonal polarized beams that are then re-imaged onto different halves of the SHARC-II bolometer array. When this removable polarimetry module is in use, SHARC-II becomes a dual-beam 12 × 12 pixel polarimeter. Sky noise is a significant source of error for submillimeter continuum observations. Because SHARP will simultaneously observe two orthogonal polarization components, we are able to eliminate or greatly reduce this source of error. Here we describe the design of SHARP and report preliminary results of tests and observations carried out during our first two runs at CSO in August 2005 and January 2006.

  12. Correlation of GOLPH3 Gene with Wnt Signaling Pathway in Human Colon Cancer Cells.

    Science.gov (United States)

    Qiu, Cheng-Zhi; Wang, Ming-Zhen; Yu, Wai-Shi; Guo, Yan-Ta; Wang, Chun-Xiao; Yang, Xiao-Feng

    2016-01-01

    Overexpression of GOLPH3 in colorectal cancer tissue may promote cell proliferation and activate the Wnt signaling pathway. We investigated the correlation between GOLPH3 gene expression and the Wnt signaling pathway to explore the mechanism of the overexpression of GOLPH3 gene which promotes proliferation in human colon cancer cells. We measured expression of GOLPH3 mRNA in the human colon cancer cell lines HCT116, HT29, SW480 and SW620 by RT-PCR, and the cells with the highest expression were selected and divided into four groups: negative control, GOLPH3 siRNA transfection (siRNA-GOLPH3), Akt inhibitor (Tricinbine), and glycogen synthase kinase (GSK)-3β inhibitor (TWS119). After human colon cancer cells were transfected with siRNA-GOLPH3, we used RT-PCR to investigate the silencing effect of GOLPH3 gene. We assessed the activity of the Wnt signaling pathway in all groups using the Topflash method. Proliferation and apoptosis of colon cancer SW620 cells were detected by MTT assay, colony formation assay and flow cytometry. Expression of Golgi phosphoprotein (GOLPH)3, β-catenin, GSK-3β and pS9-GSK-3β in cancer cells was determined by Western blotting. SW620 cells expressed the highest level of GOLPH3 mRNA, and the silence effect was good after they were transfected with siRNA-GOLPH3. The relative luminescence units (RLU) values in the experimental groups were significantly lower than in the negative control group (P 0.05). The growth inhibition ratio and apoptosis rate of cancer cells in each experimental group were significantly higher than those in the control group, and the cell colony count in the experimental group was significantly lower than in the control group (Pcancer cells did not differ significantly between each two experimental groups. Western blotting showed that, compared with the control group, expression of β-catenin and pS9-GSK3 proteins were significantly decreased in the experimental group. Expression of GSK-3β in the experimental group

  13. Development of a Wien filter electron polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Dowlatshahi, N.M

    1999-04-01

    According to current ideas only left-handed fermion currents participate in the weak interaction. However there exist left-right symmetric variants of electroweak theory with right-handed currents which couple with equal intrinsic strength, whose contribution is suppressed by the presumed relatively greater mass of the mediating vector bosons. One route to detecting the presence of right-handed currents is to measure the velocity-dependence of the polarization of electrons from mixed Fermi/Gamow-Teller {beta}-transitions. This thesis describes the theory, construction and operation of a Wien filter which is a system of crossed uniform electric and magnetic fields which transmits electrons of velocity v = E/B, and is therefore an ideal instrument for precise velocity measurements. The filter is based on a 2.5 meter long uniform field electromagnet purpose built at Oak Ridge some thirty years ago to study the electric and magnetic dipole moments of the neutron. The thesis comes in two parts: the first part presents the exact theory of relativistic electron motion in an ideal crossed field system, together with numerical programs for examining the effects of imperfections of which electric field non-uniformity and remnant magnetism turn out to be the most important. This is followed by the constructional details of the velocity filter including electric and magnetic field measurements, vacuum performance and the method for detecting and processing electron signals. This part concludes with an account of the successful testing of the filter using 62.5 keV and 84.5 keV internal conversion electrons from an electron-capture source of 453 day {sup 109}Cd. The second part of the thesis deals with the dynamics of electron spin motion in crossed fields; in particular with spin rotation from longitudinal to transverse orientation which is necessary for applying the method of Mott scattering from heavy nuclei for electron polarization determination. This part also describes

  14. Unique electron polarimeter analyzing power comparison and precision spin-based energy measurement

    International Nuclear Information System (INIS)

    Joseph Grames; Charles Sinclair; Joseph Mitchell; Eugene Chudakov; Howard Fenker; Arne Freyberger; Douglas Higinbotham; Poelker, B.; Michael Steigerwald; Michael Tiefenback; Christian Cavata; Stephanie Escoffier; Frederic Marie; Thierry Pussieux; Pascal Vernin; Samuel Danagoulian; Kahanawita Dharmawardane; Renee Fatemi; Kyungseon Joo; Markus Zeier; Viktor Gorbenko; Rakhsha Nasseripour; Brian Raue; Riad Suleiman; Benedikt Zihlmann

    2004-01-01

    Precision measurements of the relative analyzing powers of five electron beam polarimeters, based on Compton, Moller, and Mott scattering, have been performed using the CEBAF accelerator at the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory). A Wien filter in the 100 keV beamline of the injector was used to vary the electron spin orientation exiting the injector. High statistical precision measurements of the scattering asymmetry as a function of the spin orientation were made with each polarimeter. Since each polarimeter receives beam with the same magnitude of polarization, these asymmetry measurements permit a high statistical precision comparison of the relative analyzing powers of the five polarimeters. This is the first time a precise comparison of the analyzing powers of Compton, Moller, and Mott scattering polarimeters has been made. Statistically significant disagreements among the values of the beam polarization calculated from the asymmetry measurements made with each polarimeter reveal either errors in the values of the analyzing power, or failure to correctly include all systematic effects. The measurements reported here represent a first step toward understanding the systematic effects of these electron polarimeters. Such studies are necessary to realize high absolute accuracy (ca. 1%) electron polarization measurements, as required for some parity violation measurements planned at Jefferson Laboratory. Finally, a comparison of the value of the spin orientation exiting the injector that provides maximum longitudinal polarization in each experimental hall leads to an independent and very precise (better than 10-4) absolute measurement of the final electron beam energy

  15. Correlations between the signal complexity of cerebral and cardiac electrical activity: a multiscale entropy analysis.

    Directory of Open Access Journals (Sweden)

    Pei-Feng Lin

    Full Text Available The heart begins to beat before the brain is formed. Whether conventional hierarchical central commands sent by the brain to the heart alone explain all the interplay between these two organs should be reconsidered. Here, we demonstrate correlations between the signal complexity of brain and cardiac activity. Eighty-seven geriatric outpatients with healthy hearts and varied cognitive abilities each provided a 24-hour electrocardiography (ECG and a 19-channel eye-closed routine electroencephalography (EEG. Multiscale entropy (MSE analysis was applied to three epochs (resting-awake state, photic stimulation of fast frequencies (fast-PS, and photic stimulation of slow frequencies (slow-PS of EEG in the 1-58 Hz frequency range, and three RR interval (RRI time series (awake-state, sleep and that concomitant with the EEG for each subject. The low-to-high frequency power (LF/HF ratio of RRI was calculated to represent sympatho-vagal balance. With statistics after Bonferroni corrections, we found that: (a the summed MSE value on coarse scales of the awake RRI (scales 11-20, RRI-MSE-coarse were inversely correlated with the summed MSE value on coarse scales of the resting-awake EEG (scales 6-20, EEG-MSE-coarse at Fp2, C4, T6 and T4; (b the awake RRI-MSE-coarse was inversely correlated with the fast-PS EEG-MSE-coarse at O1, O2 and C4; (c the sleep RRI-MSE-coarse was inversely correlated with the slow-PS EEG-MSE-coarse at Fp2; (d the RRI-MSE-coarse and LF/HF ratio of the awake RRI were correlated positively to each other; (e the EEG-MSE-coarse at F8 was proportional to the cognitive test score; (f the results conform to the cholinergic hypothesis which states that cognitive impairment causes reduction in vagal cardiac modulation; (g fast-PS significantly lowered the EEG-MSE-coarse globally. Whether these heart-brain correlations could be fully explained by the central autonomic network is unknown and needs further exploration.

  16. Aconitase regulation of erythropoiesis correlates with a novel licensing function in erythropoietin-induced ERK signaling.

    Directory of Open Access Journals (Sweden)

    Anne-Laure Talbot

    Full Text Available Erythroid development requires the action of erythropoietin (EPO on committed progenitors to match red cell output to demand. In this process, iron acts as a critical cofactor, with iron deficiency blunting EPO-responsiveness of erythroid progenitors. Aconitase enzymes have recently been identified as possible signal integration elements that couple erythropoiesis with iron availability. In the current study, a regulatory role for aconitase during erythropoiesis was ascertained using a direct inhibitory strategy.In C57BL/6 mice, infusion of an aconitase active-site inhibitor caused a hypoplastic anemia and suppressed responsiveness to hemolytic challenge. In a murine model of polycythemia vera, aconitase inhibition rapidly normalized red cell counts, but did not perturb other lineages. In primary erythroid progenitor cultures, aconitase inhibition impaired proliferation and maturation but had no effect on viability or ATP levels. This inhibition correlated with a blockade in EPO signal transmission specifically via ERK, with preservation of JAK2-STAT5 and Akt activation. Correspondingly, a physical interaction between ERK and mitochondrial aconitase was identified and found to be sensitive to aconitase inhibition.Direct aconitase inhibition interferes with erythropoiesis in vivo and in vitro, confirming a lineage-selective regulatory role involving its enzymatic activity. This inhibition spares metabolic function but impedes EPO-induced ERK signaling and disturbs a newly identified ERK-aconitase physical interaction. We propose a model in which aconitase functions as a licensing factor in ERK-dependent proliferation and differentiation, thereby providing a regulatory input for iron in EPO-dependent erythropoiesis. Directly targeting aconitase may provide an alternative to phlebotomy in the treatment of polycythemia vera.

  17. Characterizing and Modeling the Noise and Complex Impedance of Feedhorn-Coupled TES Polarimeters

    Science.gov (United States)

    Appel, J. W.; Austermann, J. E.; Beall, J. A.; Becker, D.; Benson, B. A.; Bleem, L. E.; Britton, J.; Chang, C. L.; Carlstrom, J. E.; Cho, H. M.; Crites, A. T.; Essinger-Hileman, T.; Everett, W.; Halverson, N. W.; Henning, J. W.; Hilton, G. C.; Irwin, K. D.; McMahon, J.; Mehl, J.; Meyer, S. S.; Niemack, M. D.; Parker, L. P.; Simon, S. M.; Staggs, S. T.; Visnjic, C.; Yoon, K. W.; Zhao, Y.

    2009-12-01

    We present results from modeling the electrothermal performance of feedhorn-coupled transition edge sensor (TES) polarimeters under development for use in cosmic microwave background (CMB) polarization experiments. Each polarimeter couples radiation from a corrugated feedhorn through a planar orthomode transducer, which transmits power from orthogonal polarization modes to two TES bolometers. We model our TES with two- and three-block thermal architectures. We fit the complex impedance data at multiple points in the TES transition. From the fits, we predict the noise spectra. We present comparisons of these predictions to the data for two TESes on a prototype polarimeter.

  18. The MESA polarimetry chain and the status of its double scattering polarimeter

    International Nuclear Information System (INIS)

    Aulenbacher, K.; Bartolomé, P. Aguar; Molitor, M.; Tioukine, V.

    2013-01-01

    We plan to have two independent polarimetry systems at MESA based on totally different physical processes. A first one tries to minimize the systematic uncertainties in double polarized Mo/ller scattering, which is to be achieved by stored hydrogen atoms in an atomic trap (Hydro-Mo/ller-Polarimeter). The other one relies on the equality of polarizing and analyzing power which allows to measure the effective analyzing power of a polarimeter with very high accuracy. Since the status of Hydro-Mo/ller is presented in a separate paper we concentrate on the double scattering polarimeter in this article

  19. On the investigation of the neurophysiological correlates of knowledge worker mental fatigue using the EEG signal.

    Science.gov (United States)

    Okogbaa, O G; Shell, R L; Filipusic, D

    1994-12-01

    Technological trends and advances in automation have underscored the importance of task performance of certain jobs requiring mental functions such as information processing and decision analyses. Most experts agree that such work environments produce increased mental activities, with profound implications for mental fatigue and stress. Consequently, productivity measurement and improvement for white collar or 'knowledge worker' occupations remains a major challenge and concern. This investigation defines an experimental approach that examines the neurophysiological correlates of white collar worker mental fatigue using the EEG signal. A 6 h laboratory experiment was conducted to simulate work output. The methods of assessing fatigue employed were mental tests and physiological measurements. The experiment involved reading of standardized texts, finding solutions to arithmetic-logical problems and a combination of both task types. Two primary performance measures were obtained, work output and brain waves. Fast Fourier transform and correlation analyses are used to quantify the relationship between certain brain waves and mental fatigue. This research is a major step towards the development of a model that explores the relationship between mental fatigue and factors associated with output performance, optimal recuperation periods and related variables. Such a model would be useful in human reliability prediction based on task parameters and worker profiles.

  20. WWC3 downregulation correlates with poor prognosis and inhibition of Hippo signaling in human gastric cancer

    Directory of Open Access Journals (Sweden)

    Hou J

    2017-06-01

    Full Text Available Jiabin Hou, Jin Zhou The First Affiliated Hospital, Harbin Medical University, Harbin, People’s Republic of China Abstract: The aim of this study was to investigate the clinicopathological significance and biological roles of WWC3 in human gastric cancer (GC. Clinical significance of WWC3 in human GCs was examined by using immunohistochemistry (IHC. WWC3 was downregulated in 48 of 111 human GCs, and its downregulation was associated with advanced stage, positive nodal status, and higher relapse rate. Importantly, WWC3 downregulation correlated with poor survival. It was also found that WWC3 protein expression was downregulated in GC cell lines compared with normal cell line GES-1. On one hand, WWC3 overexpression inhibited the cell growth rate and invading ability in HGC-27 cell line. On the other hand, depleting WWC3 by small interfering RNA (siRNA promoted proliferation rate and invading ability in the SGC-7901 cell line. In addition, cell cycle analysis showed that WWC3 overexpression inhibited while its depletion accelerated cell cycle progression at the G1/S transition. Western blot (WB analysis demonstrated that WWC3 repressed cyclin D1 and cyclin E while upregulated p27 expression. Luciferase reporter assay showed that WWC3 activated Hippo signaling pathway by suppressing TEAD transcription activity, with downregulation of total and nuclear YAP and its target CTGF. WWC3 siRNA depletion exhibited the opposite effects. In conclusion, this study indicates that WWC3 serves as a tumor suppressor in GC by activating Hippo signaling. Keywords: WWC3, gastric cancer, cell cycle, Hippo, YAP

  1. Validation of a raw data-based synchronization signal (kymogram) for phase-correlated cardiac image reconstruction

    International Nuclear Information System (INIS)

    Ertel, Dirk; Kachelriess, Marc; Kalender, Willi A.; Pflederer, Tobias; Achenbach, Stephan; Steffen, Peter

    2008-01-01

    Phase-correlated reconstruction is commonly used in computed tomography (CT)-based cardiac imaging. Alternatively to the commonly used ECG, the raw data-based kymogram function can be used as a synchronization signal. We used raw data of 100 consecutive patient exams to compare the performance of kymogram function to the ECG signal. For objective validation the correlation of the ECG and the kymogram was assessed. Additionally, we performed a double-blinded comparison of ECG-based and kymogram-based phase-correlated images. The two synchronization signals showed good correlation indicated by a mean difference in the detected heart rate of negligible 0.2 bpm. The mean image quality score was 2.0 points for kymogram-correlated images and 2.3 points for ECG-correlated images, respectively (3: best; 0: worst). The kymogram and the ECG provided images adequate for diagnosis for 93 and 97 patients, respectively. For 50% of the datasets the kymogram provided an equivalent or even higher image quality compared with the ECG signal. We conclude that an acceptable image quality can be assured in most cases by the kymogram. Improvements of image quality by the kymogram function were observed in a noticeable number of cases. The kymogram can serve as a backup solution when an ECG is not available or lacking in quality. (orig.)

  2. Passive New UV Polarimeter for Remote Surface and Atmospheric Sensing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Our imaging polarimeter concept makes available for the first time, the passive remote imagery of all four Stokes vector components at UV wavelengths shorter than...

  3. Development of the GEM-TPC X-ray Polarimeter with the Scalable Readout System

    Directory of Open Access Journals (Sweden)

    Kitaguchi Takao

    2018-01-01

    Full Text Available We have developed a gaseous Time Projection Chamber (TPC containing a single-layered foil of a gas electron multiplier (GEM to open up a new window on cosmic X-ray polarimetry in the 2–10 keV band. The micro-pattern TPC polarimeter in combination with the Scalable Readout System produced by the RD51 collaboration has been built as an engineering model to optimize detector parameters and improve polarimeter sensitivity. The polarimeter was characterized with unpolarized X-rays from an X-ray generator in a laboratory and polarized X-rays on the BL32B2 beamline at the SPring-8 synchrotron radiation facility. Preliminary results show that the polarimeter has a comparable modulation factor to a prototype of the flight one.

  4. The Hertz/VPM Polarimeter: Design and First Light Observations

    Science.gov (United States)

    Krejny, Megan; Chuss, David; d'Aubigny, Christian Drouet; Golish, Dathon; Houde, Martin; Hui, Howard; Kulesa, Craig; Loewenstein, Robert F.; Moseley, Harvey; Novak, Giles; hide

    2008-01-01

    We present first results of Hertz/VPM, the first submillimeter polarimeter employing the dual Variable-delay Polarization Modulator (dual-VPM). This device differs from previously used polarization modulators in that it, operates in translation rather than mechanical rotation. We discuss the basic theory behind this device, and its potential advantages over the commonly used half wave plate (HFVP). The dual-VPM was tested both at the Submillimeter Telescope Observatory (SMTO) and in the lab. In each case we present a detailed description of the setup. We discovered nonideal behavior in the system. This is at least in part due to properties of the VPM wire grids (diameter, spacing) employed in our experiment. Despite this, we found that the dual-VPM system is robust, operating with high efficiency and low instrumental polarization. This device is well suited for air and space-borne applications.

  5. Interpolation strategies for reducing IFOV artifacts in microgrid polarimeter imagery.

    Science.gov (United States)

    Ratliff, Bradley M; LaCasse, Charles F; Tyo, J Scott

    2009-05-25

    Microgrid polarimeters are composed of an array of micro-polarizing elements overlaid upon an FPA sensor. In the past decade systems have been designed and built in all regions of the optical spectrum. These systems have rugged, compact designs and the ability to obtain a complete set of polarimetric measurements during a single image capture. However, these systems acquire the polarization measurements through spatial modulation and each measurement has a varying instantaneous field-of-view (IFOV). When these measurements are combined to estimate the polarization images, strong edge artifacts are present that severely degrade the estimated polarization imagery. These artifacts can be reduced when interpolation strategies are first applied to the intensity data prior to Stokes vector estimation. Here we formally study IFOV error and the performance of several bilinear interpolation strategies used for reducing it.

  6. Rocket Experiment Demonstration of a Soft X-ray Polarimeter

    Science.gov (United States)

    Marshall, Herman

    This proposal is the lead proposal. Boston University will submit, via NSPIRES, a Co-I proposal, per instructions for Suborbital proposals for multiple-award. Our scientific goal of the Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX Polarimeter) is to make the first measurement of the linear X-ray polarization of an extragalactic source in the 0.2-0.8 keV band. The first flight of the REDSoX Polarimeter would target Mk 421, which is commonly modeled as a highly relativistic jet aimed nearly along the line of sight. Such sources are likely to be polarized at a level of 30-60%, so the goal is to obtain a significant detection even if it is as low as 10%. Significant revisions to the models of jets emanating from black holes at the cores of active galaxies would be required if the polarization fraction lower than 10%. We employ multilayer-coated mirrors as Bragg reflectors at the Brewster angle. By matching to the dispersion of a spectrometer, one may take advantage of high multilayer reflectivities and achieve polarization modulation factors over 90%. Using replicated foil mirrors from MSFC and gratings made at MIT, we construct a spectrometer that disperses to three laterally graded multilayer mirrors (LGMLs). The lateral grading changes the wavelength of the Bragg peak for 45 degree reflections linearly across the mirror, matching the dispersion of the spectrometer. By dividing the entrance aperture into six equal sectors, pairs of blazed gratings from opposite sectors are oriented to disperse to the same LGML. The position angles for the LGMLs are 120 degrees to each other. CCD detectors then measure the intensities of the dispersed spectra after reflection and polarizing by the LGMLs, giving the three Stokes parameters needed to determine the source polarization. We will rely on components whose performance has been verified in the laboratory or in space. The CCD detectors are based on Chandra and Suzaku heritage. The mirror fabrication team

  7. CLASP2: The Chromospheric LAyer Spectro-Polarimeter

    Science.gov (United States)

    Rachmeler, Laurel; E McKenzie, David; Ishikawa, Ryohko; Trujillo Bueno, Javier; Auchère, Frédéric; Kobayashi, Ken; Winebarger, Amy; Bethge, Christian; Kano, Ryouhei; Kubo, Masahito; Song, Donguk; Narukage, Noriyuki; Ishikawa, Shin-nosuke; De Pontieu, Bart; Carlsson, Mats; Yoshida, Masaki; Belluzzi, Luca; Stepan, Jiri; del Pino Alemná, Tanausú; Ballester, Ernest Alsina; Asensio Ramos, Andres

    2017-08-01

    We present the instrument, science case, and timeline of the CLASP2 sounding rocket mission. The successful CLASP (Chromospheric Lyman-Alpha Spectro-Polarimeter) sounding rocket flight in 2015 resulted in the first-ever linear polarization measurements of solar hydrogen Lyman-alpha line, which is sensitive to the Hanle effect and can be used to constrain the magnetic field and geometric complexity of the upper chromosphere. Ly-alpha is one of several upper chromospheric lines that contain magnetic information. In the spring of 2019, we will re-fly the modified CLASP telescope to measure the full Stokes profile of Mg II h & k near 280 nm. This set of lines is sensitive to the upper chromospheric magnetic field via both the Hanle and the Zeeman effects.

  8. Faraday rotation calculations for a FIR polarimeter on ITER

    International Nuclear Information System (INIS)

    Nieswand, C.

    1997-01-01

    The measurement of the safety factor profile has been considered as an essential diagnostics for ITER. Without the presence of a neutral beam, the only reliable diagnostics which can fulfill the requirements for the q-profile determination is at present the polarimetry. This paper presents the results of calculations of the Faraday rotation and the Cotton-Mouton effect for various plasma configurations (considered as typical) and various beam geometries which can eventually be realized in spite of the restricted access. The calculations should help to find a decision for the wavelength and the number and the position of the observation chords of a possible polarimeter system on ITER. The paper does not deal with technical questions concerning the implementation of such a system on ITER. The potential use of internal retro-reflectors or waveguides for the beams is not discussed. (author) 4 figs., 3 refs

  9. Analysis of AGS polarimeter data at G gamma=7.5.

    CERN Document Server

    Huang, H; Spinka, H M; Underwood, D G

    2003-01-01

    Data were collected with the AGS internal polarimeter at G gamma = 7.5 during the recent FY02 polarized proton run. The addition of new forward scintillation counters permitted an absolute calibration of the polarimeter for both nylon and carbon targets. The results are summarized, and the polarization measured at G gamma = 7.5 is compared to that at 200 MeV.

  10. Unambiguous Tracking Method Based on Combined Correlation Functions for sine/cosine-BOC CBOC and AltBOC Modulated Signals

    OpenAIRE

    J.W. Ren; G.T. Yang; W.M. Jia; M.L. Yao

    2014-01-01

    Unambiguous tracking for Binary Offset Carrier (BOC) modulated signals is an important requirement of modern Global Navigation Satellite System (GNSS) receivers. An unambiguous tracking method based on combined correlation functions for even/odd order sine/cosine-BOC, Composite BOC(CBOC) and Alternate BOC(AltBOC) modulated signals is proposed. Firstly, a unitary mathematical formulation for all kinds of BOC modulations is introduced. Then an unambiguous tracking method is proposed based on th...

  11. Photoacoustic signal characterization of cancer treatment response: Correlation with changes in tumor oxygenation

    Directory of Open Access Journals (Sweden)

    Eno Hysi

    2017-03-01

    Full Text Available Frequency analysis of the photoacoustic radiofrequency signals and oxygen saturation estimates were used to monitor the in-vivo response of a novel, thermosensitive liposome treatment. The liposome encapsulated doxorubicin (HaT-DOX releasing it rapidly (<20 s when the tumor was exposed to mild hyperthermia (43 °C. Photoacoustic imaging (VevoLAZR, 750/850 nm, 40 MHz of EMT-6 breast cancer tumors was performed 30 min pre- and post-treatment and up to 7 days post-treatment (at 2/5/24 h timepoints. HaT-DOX-treatment responders exhibited on average a 22% drop in oxygen saturation 2 h post-treatment and a decrease (45% at 750 nm and 73% at 850 nm in the slope of the normalized PA frequency spectra. The spectral slope parameter correlated with treatment-induced hemorrhaging which increased the optical absorber effective size via interstitial red blood cell leakage. Combining frequency analysis and oxygen saturation estimates differentiated treatment responders from non-responders/control animals by probing the treatment-induced structural changes of blood vessel.

  12. Passive correlation ranging of a geostationary satellite using DVB-S payload signals.

    Science.gov (United States)

    Shakun, Leonid; Shulga, Alexandr; Sybiryakova, Yevgeniya; Bushuev, Felix; Kaliuzhnyi, Mykola; Bezrukovs, Vladislavs; Moskalenko, Sergiy; Kulishenko, Vladislav; Balagura, Oleg

    2016-07-01

    Passive correlation ranging (PaCoRa) for geostationary satellites is now considered as an alternate to tone-ranging (https://artes.esa.int/search/node/PaCoRa). The PaCoRa method has been employed in the Research Institute "Nikolaev astronomical observatory" since the first experiment in August 2011 with two stations spatially separated on 150 km. The PaCoRa has been considered as an independent method for tracking the future Ukrainian geostationary satellite "Lybid'. Now a radio engineering complex (RC) for passive ranging consists of five spatially separated stations of receiving digital satellite television and a data processing center located in Mykolaiv. The stations are located in Kyiv, Kharkiv, Mukacheve, Mykolaiv (Ukraine) and in Ventspils (Latvia). Each station has identical equipment. The equipment allows making synchronous recording of fragments of the DVB-S signal from the quadrature detector output of a satellite television receiver. The fragments are recorded every second. Synchronization of the stations is performed using GPS receivers. Samples of the complex signal obtained in this way are archived and are sent to the data processing center over the Internet. Here the time differences of arrival (TDOA) for pairs of the stations are determined as a result of correlation processing of received signals. The values of the TDOA that measured every second are used for orbit determination (OD) of the satellite. The results of orbit determination of the geostationary telecommunication satellite "Eutelsat-13B" (13º East) obtained during about four months of observations in 2015 are presented in the report. The TDOA and OD accuracies are also given. Single-measurement error (1 sigma) of the TDOA is equal about 8.7 ns for all pairs of the stations. Standard deviations and average values of the residuals between the observed TDOA and the TDOA computed using the orbit elements obtained from optical measurements are estimated for the pairs Kharkiv-Mykolaiv and

  13. Effects of stray lights on Faraday rotation measurement for polarimeter-interferometer system on EAST

    Science.gov (United States)

    Zou, Z. Y.; Liu, H. Q.; Ding, W. X.; Chen, J.; Brower, D. L.; Lian, H.; Wang, S. X.; Li, W. M.; Yao, Y.; Zeng, L.; Jie, Y. X.

    2018-01-01

    A double-pass radially view 11 chords polarimeter-interferometer system has been operated on the experimental advanced superconducting tokamak and provides important current profile information for plasma control. Stray light originating from spurious reflections along the optical path (unwanted reflections from various optical components/mounts and transmissive optical elements such as windows, waveplates, and lens as well as the detectors) and also direct feedback from the retro-reflector used to realize the double-pass configuration can both contribute to contamination of the Faraday rotation measurement accuracy. Modulation of the Faraday rotation signal due to the interference from multiple reflections is observable when the interferometer phase (plasma density) varies with time. Direct reflection from the detector itself can be suppressed by employing an optical isolator consisting of a λ/4-waveplate and polarizer positioned in front of the mixer. A Faraday angle oscillation during the density ramping up (or down) can be reduced from 5°-10° to 1°-2° by eliminating reflections from the detector. Residual modulation arising from misalignment and stray light from other sources must be minimized to achieve accurate measurements of Faraday rotation.

  14. Squids, snakes, and polarimeters: A new technique for measuring the magnetic moments of polarized beams

    International Nuclear Information System (INIS)

    Cameron, P.R.; Luccio, A.U.; Shea, T.J.; Tsoupas, N.; Goldberg, D.A.

    1997-01-01

    Effective polarimetry at high energies in hadron and lepton synchrotrons has been a long-standing and difficult problem. In synchrotrons with polarized beams it is possible to cause the direction of the polarization vector of a given bunch to alternate at a frequency which is some subharmonic of the rotation frequency. This can result in the presence of lines in the beam spectrum which are due only to the magnetic moment of the beam and which are well removed from the various lines due to the charge of the beam. The magnitude of these lines can be calculated from first principles. They are many orders of magnitude weaker than the Schottky signals. Measurement of the magnitude of one of these lines would be an absolute measurement of beam polarization. For measuring magnetic field, the Superconducting Quantum Interference Device, or squid, is about five orders of magnitude more sensitive than any other transducer. Using a squid, such a measurement might be accomplished with the proper combination of shielding, pickup loop design, and filtering. The resulting instrument would be fast, non-destructive, and comparatively cheap. In addition, techniques developed in the creation of such an instrument could be used to measure the Schottky spectrum in unprecedented detail. We present specifics of a polarimeter design for the Relativistic Heavy Ion Collider (RHIC) and briefly discuss the possibility of using this technique to measure polarization at high-energy electron machines like LEP and HERA. copyright 1997 American Institute of Physics

  15. Scanning polarimeter for measurement of the poloidal magnetic field in a tokamak

    International Nuclear Information System (INIS)

    Wroblewski, D.; Huang, L.K.; Moos, H.W.

    1988-01-01

    The internal magnetic field in a magnetically confined plasma may be deduced from the analysis of circular polarization of spectral lines emitted by the plasma. The theory of the measurement and a detailed design of a polarimeter constructed to measure the poloidal field profile in the Texas Experimental Tokamak (TEXT) are presented. The instrument measures the difference between left-hand and right-hand circularly polarized line profiles, a quantity directly proportional to the magnetic field component in the direction of observation. The high throughput of the Fabry--Perot interferometer employed in this design, combined with efficient light-collecting optics and lock-in detection of the polarization signal, allows measurement of the fractional circular polarization of the magnetic dipole line Ti XVII 3834 A with an accuracy on the order of 10 -3 . The line-of-sight averaged poloidal field is determined with uncertainty as small as 50 G. The line emission used in the present measurement is not well localized in the plasma, necessitating the use of a spatial inversion procedure to obtain the local values of the field

  16. The Primordial Inflation Explorer (PIXIE): A Nulling Polarimeter for Cosmic Microwave Background Observations

    Science.gov (United States)

    Kogut, Alan J.; Fixsen, D. J.; Chuss, D. T.; Dotson, J.; Dwek, E.; Halpern, M.; Hinshaw, G. F.; Meyer, S. M.; Moseley, S. H.; Seiffert, M. D.; hide

    2011-01-01

    The Primordial Inflation Explorer (PIXIE) is a concept for an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. The instrument consists of a polarizing Michelson interferometer configured as a nulling polarimeter to measure the difference spectrum between orthogonal linear polarizations from two co-aligned beams. Either input can view the sky or a temperature-controlled absolute reference blackbody calibrator. Rhe proposed instrument can map the absolute intensity and linear polarization (Stokes I, Q, and U parameters) over the full sky in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded optics provide background-limited sensitivity using only 4 detectors, while the highly symmetric design and multiple signal modulations provide robust rejection of potential systematic errors. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r < 10..3 at 5 standard deviations. The rich PIXIE data set can also constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy.

  17. Noise reduction in Lidar signal using correlation-based EMD combined with soft thresholding and roughness penalty

    Science.gov (United States)

    Chang, Jianhua; Zhu, Lingyan; Li, Hongxu; Xu, Fan; Liu, Binggang; Yang, Zhenbo

    2018-01-01

    Empirical mode decomposition (EMD) is widely used to analyze the non-linear and non-stationary signals for noise reduction. In this study, a novel EMD-based denoising method, referred to as EMD with soft thresholding and roughness penalty (EMD-STRP), is proposed for the Lidar signal denoising. With the proposed method, the relevant and irrelevant intrinsic mode functions are first distinguished via a correlation coefficient. Then, the soft thresholding technique is applied to the irrelevant modes, and the roughness penalty technique is applied to the relevant modes to extract as much information as possible. The effectiveness of the proposed method was evaluated using three typical signals contaminated by white Gaussian noise. The denoising performance was then compared to the denoising capabilities of other techniques, such as correlation-based EMD partial reconstruction, correlation-based EMD hard thresholding, and wavelet transform. The use of EMD-STRP on the measured Lidar signal resulted in the noise being efficiently suppressed, with an improved signal to noise ratio of 22.25 dB and an extended detection range of 11 km.

  18. Magnetic Resonance Signal, Rather Than Tendon Volume, Correlates to Pain and Functional Impairment in Chronic Achilles Tendinopathy

    Energy Technology Data Exchange (ETDEWEB)

    Gaerdin, A.; Bruno, J.; Movin, T.; Kristoffersen-Wiberg, M.; Shalabi, A. [Karolinska Univ. Hospital, Stockholm (Sweden). Depts. of Radiology and Orthopedics

    2006-09-15

    Purpose: To depict abnormal tendon matrix composition using magnetic resonance imaging (MRI) in chronic Achilles tendinopathy, and correlate intratendinous signal alterations to pain and functional impairment. Material and Methods: MRI of the Achilles tendon was performed on 25 patients with chronic Achilles tendinopathy (median age 50, range 37-71 years). All patients suffered from pain in the mid-portion of the Achilles tendon. Intratendinous signal was calculated from five different sagittal sequences, using a computerized 3D seed-growing technique. Pain and functional impairment were evaluated using a questionnaire completed by patients. Results: Severity of pain and functional impairment correlated to increased mean intratendinous signal in the painful tendon in all MR sequences (P 0.05). Difference in mean intratendinous signal between symptomatic and contralateral asymptomatic tendons was highly significant in all sequences (P <0.05) except on T2-weighted images (P = 0.6). Conclusion: Severity of pain and disability correlated to increased MR signal rather than to tendon volume in patients with unilateral mid-portion chronic Achilles tendinopathy.

  19. Harmful intrusion detection algorithm of optical fiber pre-warning system based on correlation of orthogonal polarization signals

    Science.gov (United States)

    Bi, Fukun; Feng, Chong; Qu, Hongquan; Zheng, Tong; Wang, Chonglei

    2017-09-01

    At present, advanced researches of optical fiber intrusion measurement are based on the constant false alarm rate (CFAR) algorithm. Although these conventional methods overcome the interference of non-stationary random signals, there are still a large number of false alarms in practical applications. This is because there is no specific study on orthogonal polarization signals of false alarm and intrusion. In order to further reduce false alarms, we analyze the correlation of optical fiber signals using birefringence of single-mode fiber. This paper proposes the harmful intrusion detection algorithm based on the correlation of two orthogonal polarization signals. The proposed method uses correlation coefficient to distinguish false alarms and intrusions, which can decrease false alarms. Experiments on real data, which are collected from the practical environment, demonstrate that the difference in correlation is a robust feature. Furthermore, the results show that the proposed algorithm can reduce the false alarms and ensure the detection performance when it is used in optical fiber pre-warning system (OFPS).

  20. Ultralow-Power Digital Correlator for Microwave Polarimetry

    Science.gov (United States)

    Piepmeier, Jeffrey R.; Hass, K. Joseph

    2004-01-01

    A recently developed high-speed digital correlator is especially well suited for processing readings of a passive microwave polarimeter. This circuit computes the autocorrelations of, and the cross-correlations among, data in four digital input streams representing samples of in-phase (I) and quadrature (Q) components of two intermediate-frequency (IF) signals, denoted A and B, that are generated in heterodyne reception of two microwave signals. The IF signals arriving at the correlator input terminals have been digitized to three levels (-1,0,1) at a sampling rate up to 500 MHz. Two bits (representing sign and magnitude) are needed to represent the instantaneous datum in each input channel; hence, eight bits are needed to represent the four input signals during any given cycle of the sampling clock. The accumulation (integration) time for the correlation is programmable in increments of 2(exp 8) cycles of the sampling clock, up to a maximum of 2(exp 24) cycles. The basic functionality of the correlator is embodied in 16 correlation slices, each of which contains identical logic circuits and counters (see figure). The first stage of each correlation slice is a logic gate that computes one of the desired correlations (for example, the autocorrelation of the I component of A or the negative of the cross-correlation of the I component of A and the Q component of B). The sampling of the output of the logic gate output is controlled by the sampling-clock signal, and an 8-bit counter increments in every clock cycle when the logic gate generates output. The most significant bit of the 8-bit counter is sampled by a 16-bit counter with a clock signal at 2(exp 8) the frequency of the sampling clock. The 16-bit counter is incremented every time the 8-bit counter rolls over.

  1. Analysis of Correlation in MEMS Gyroscope Array and its Influence on Accuracy Improvement for the Combined Angular Rate Signal

    Directory of Open Access Journals (Sweden)

    Liang Xue

    2018-01-01

    Full Text Available Obtaining a correlation factor is a prerequisite for fusing multiple outputs of a mircoelectromechanical system (MEMS gyroscope array and evaluating accuracy improvement. In this paper, a mathematical statistics method is established to analyze and obtain the practical correlation factor of a MEMS gyroscope array, which solves the problem of determining the Kalman filter (KF covariance matrix Q and fusing the multiple gyroscope signals. The working principle and mathematical model of the sensor array fusion is briefly described, and then an optimal estimate of input rate signal is achieved by using of a steady-state KF gain in an off-line estimation approach. Both theoretical analysis and simulation show that the negative correlation factor has a favorable influence on accuracy improvement. Additionally, a four-gyro array system composed of four discrete individual gyroscopes was developed to test the correlation factor and its influence on KF accuracy improvement. The result showed that correlation factors have both positive and negative values; in particular, there exist differences for correlation factor between the different units in the array. The test results also indicated that the Angular Random Walk (ARW of 1.57°/h0.5 and bias drift of 224.2°/h for a single gyroscope were reduced to 0.33°/h0.5 and 47.8°/h with some negative correlation factors existing in the gyroscope array, making a noise reduction factor of about 4.7, which is higher than that of a uncorrelated four-gyro array. The overall accuracy of the combined angular rate signal can be further improved if the negative correlation factors in the gyroscope array become larger.

  2. Design, construction and calibration of a polarimeter for gamma radiation

    International Nuclear Information System (INIS)

    Macchiavelli, A.O.; Marti, G.V.; Gimenez, C.R.; Laffranchi, J.A.; Behar, M.

    1980-01-01

    Information on different nuclear states can be obtained from the analysis of the angular distribution of the emitted gamma radiation. When the information is not sufficient to determine certain relevant parameters, or is ambiguous, a measurement of the linear polarization of radiation together with the angular distribution allows, in many cases, to resolve this ambiguity. This in turn, necessitates of a detector radiation: this is a Ge(Li) planar detector with a width d of the compensated zone smaller than the length L (L/d greater than 1), built from a germanium block with a square section of 33 mm side, compensated with lithium up to 3 mm depth, by means of usual techniques. The detector characteristics, measured by conventional electronics, were: system's total resolution (Full Width at Half Maximum) 2.4 keV; pico-Compton relation of 6/1 and relative efficiency of 0. for γ rays of 1.33 MeV from 60 Co. Using γ-γ fast-slow coincidence techniques (Ge(Li)-INa system), the curve of polarization efficiency in the 0.1.5 MeV energy range was determined and a polarization efficiency of approximately 17% was obtained for said energy range. This value is comparable to the results obtained in previous works for polarimeters of similar dimensions and can be used to determine multipolarity of nuclear states. (M.E.L.) [es

  3. Magnitude and sign of long-range correlated time series: Decomposition and surrogate signal generation.

    Science.gov (United States)

    Gómez-Extremera, Manuel; Carpena, Pedro; Ivanov, Plamen Ch; Bernaola-Galván, Pedro A

    2016-04-01

    We systematically study the scaling properties of the magnitude and sign of the fluctuations in correlated time series, which is a simple and useful approach to distinguish between systems with different dynamical properties but the same linear correlations. First, we decompose artificial long-range power-law linearly correlated time series into magnitude and sign series derived from the consecutive increments in the original series, and we study their correlation properties. We find analytical expressions for the correlation exponent of the sign series as a function of the exponent of the original series. Such expressions are necessary for modeling surrogate time series with desired scaling properties. Next, we study linear and nonlinear correlation properties of series composed as products of independent magnitude and sign series. These surrogate series can be considered as a zero-order approximation to the analysis of the coupling of magnitude and sign in real data, a problem still open in many fields. We find analytical results for the scaling behavior of the composed series as a function of the correlation exponents of the magnitude and sign series used in the composition, and we determine the ranges of magnitude and sign correlation exponents leading to either single scaling or to crossover behaviors. Finally, we obtain how the linear and nonlinear properties of the composed series depend on the correlation exponents of their magnitude and sign series. Based on this information we propose a method to generate surrogate series with controlled correlation exponent and multifractal spectrum.

  4. Lifetime estimation of a time projection chamber x-ray polarimeter

    Science.gov (United States)

    Hill, Joanne E.; Black, J. Kevin; Brieda, Lubos; Dickens, Patsy L.; Montt de Garcia, Kristina; Hawk, Douglas L.; Hayato, Asami; Jahoda, Keith; Mohammed, Jelila

    2013-09-01

    The Gravity and Extreme Magnetism Small Explorer (GEMS) X-ray polarimeter Instrument (XPI) was designed to measure the polarization of 23 sources over the course of its 9 month mission. The XPI design consists of two telescopes each with a polarimeter assembly at the focus of a grazing incidence mirror. To make sensitive polarization measurements the GEMS Polarimeter Assembly (PA) employed a gas detection system based on a Time Projection Chamber (TPC) technique. Gas detectors are inherently at risk of degraded performance arising from contamination from outgassing of internal detector components or due to loss of gas. This paper describes the design and the materials used to build a prototype of the flight polarimeter with the required GEMS lifetime. We report the results from outgassing measurements of the polarimeter subassemblies and assemblies, enclosure seal tests, life tests, and performance tests that demonstrate that the GEMS lifetime is achievable. Finally we report performance measurements and the lifetime enhancement from the use of a getter.

  5. Run05 Proton Beam Polarization Measurements by pC-Polarimeter (ver. 1.1)

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa,I.; Alekseev, I.; Bazilevsky, A.; Bravar, A.; Bunce, G.; Dhawan, S.; Eyser, K.O.; Gill, R.; Haeberli, W.; Huang, H.; Makdisi, Y.; Nass, A.; Okada, H.; Stephenson, E.; Svirida, D.N.; Wise, T.; Wood, J.; Yip, K.; Zelenski, A.

    2008-07-01

    The polarization of the proton beams [1, 2] at the Relativistic Heavy Ion Collider (RHIC)[3] RHIC ring. The H-Jet polarimeter is located at the collision point allowing measurements of absolute normalization is provided by the hydrogen polarimeter, which measures over 1 {approx} 2 another measurement rather than measuring the absolute polarization. both beams. Two identical pC-polarimeters are equipped in the yellow and blue rings, where carbon ribbon target, providing fast feedback to beam operations and experiments. The days to obtain {approx} 5% statistical uncertainty (in Run05). Thus, the operation of the carbon is measured using both an atomic beam source hydrogen gas jet (H-Jet)[4, 5] and proton-carbon polarimeters was focused on better control of relative stability between one measurement to statistical accuracy within 20 to 30 seconds using an ultra-thin (typically 6 {approx} 8 {micro}g/cm{sup 2}) the rings are separated. The pC-polarimeter measures relative polarization to a few percent.

  6. Airborne Polarimeter Intercomparison for the NASA Aerosols-Clouds-Ecosystems (ACE) Mission

    Science.gov (United States)

    Knobelspiesse, Kirk; Redemann, Jens

    2014-01-01

    The Aerosols-Clouds-Ecosystems (ACE) mission, recommended by the National Research Council's Decadal Survey, calls for a multi-angle, multi-spectral polarimeter devoted to observations of atmospheric aerosols and clouds. In preparation for ACE, NASA funds the deployment of airborne polarimeters, including the Airborne Multi-angle SpectroPolarimeter Imager (AirMSPI), the Passive Aerosol and Cloud Suite (PACS) and the Research Scanning Polarimeter (RSP). These instruments have been operated together on NASA's ER-2 high altitude aircraft as part of field campaigns such as the POlarimeter DEfinition EXperiment (PODEX) (California, early 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, California and Texas, summer 2013). Our role in these efforts has been to serve as an assessment team performing level 1 (calibrated radiance, polarization) and level 2 (retrieved geophysical parameter) instrument intercomparisons, and to promote unified and generalized calibration, uncertainty assessment and retrieval techniques. We will present our progress in this endeavor thus far and describe upcoming research in 2015.

  7. Progress in Airborne Polarimeter Inter Comparison for the NASA Aerosols-Clouds-Ecosystems (ACE) Mission

    Science.gov (United States)

    Knobelspiesse, Kirk; Redemann, Jens

    2014-01-01

    The Aerosols-Clouds-Ecosystems (ACE) mission, recommended by the National Research Council's Decadal Survey, calls for a multi-angle, multi-spectral polarimeter devoted to observations of atmospheric aerosols and clouds. In preparation for ACE, NASA funds the deployment of airborne polarimeters, including the Airborne Multiangle SpectroPolarimeter Imager (AirMSPI), the Passive Aerosol and Cloud Suite (PACS) and the Research Scanning Polarimeter (RSP). These instruments have been operated together on NASA's ER-2 high altitude aircraft as part of field campaigns such as the POlarimeter DEfinition EXperiment (PODEX) (California, early 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, California and Texas, summer 2013). Our role in these efforts has been to serve as an assessment team performing level 1 (calibrated radiance, polarization) and level 2 (retrieved geophysical parameter) instrument intercomparisons, and to promote unified and generalized calibration, uncertainty assessment and retrieval techniques. We will present our progress in this endeavor thus far and describe upcoming research in 2015.

  8. Atypical Diabetic Foot Ulcer Keratinocyte Protein Signaling Correlates with Impaired Wound Healing

    Directory of Open Access Journals (Sweden)

    Glenn D. Hoke

    2016-01-01

    Full Text Available Diabetes mellitus is associated with chronic diabetic foot ulcers (DFUs and wound infections often resulting in lower extremity amputations. The protein signaling architecture of the mechanisms responsible for impaired DFU healing has not been characterized. In this preliminary clinical study, the intracellular levels of proteins involved in signal transduction networks relevant to wound healing were non-biasedly measured using reverse-phase protein arrays (RPPA in keratinocytes isolated from DFU wound biopsies. RPPA allows for the simultaneous documentation and assessment of the signaling pathways active in each DFU. Thus, RPPA provides for the accurate mapping of wound healing pathways associated with apoptosis, proliferation, senescence, survival, and angiogenesis. From the study data, we have identified potential diagnostic, or predictive, biomarkers for DFU wound healing derived from the ratios of quantified signaling protein expressions within interconnected pathways. These biomarkers may allow physicians to personalize therapeutic strategies for DFU management on an individual basis based upon the signaling architecture present in each wound. Additionally, we have identified altered, interconnected signaling pathways within DFU keratinocytes that may help guide the development of therapeutics to modulate these dysregulated pathways, many of which parallel the therapeutic targets which are the hallmarks of molecular therapies for treating cancer.

  9. Calibration of the Gamma-RAy Polarimeter Experiment (GRAPE) at a polarized hard X-ray beam

    International Nuclear Information System (INIS)

    Bloser, P.F.; Legere, J.S.; McConnell, M.L.; Macri, J.R.; Bancroft, C.M.; Connor, T.P.; Ryan, J.M.

    2009-01-01

    The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50-500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module containing a single CsI(Na) calorimeter element, at the center of the MAPMT, surrounded by 60 plastic elements. The prototype has been combined with custom readout electronics and software to create a complete 'engineering model' of the GRAPE instrument. This engineering model has been calibrated using a nearly 100% polarized hard X-ray beam at the Advanced Photon Source at Argonne National Laboratory. We find modulation factors of 0.46±0.06 and 0.48±0.03 at 69.5 and 129.5 keV, respectively, in good agreement with Monte Carlo simulations. In this paper we present details of the beam test, data analysis, and simulations, and discuss the implications of our results for the further development of the GRAPE concept.

  10. Using a polarizing film in the manufacture of panoramic Stokes polarimeters at the Main Astronomical Observatory of NAS of Ukraine

    Science.gov (United States)

    Syniavskyi, I.; Ivanov, Yu.; Vidmachenko, A. P.; Sergeev, A.

    2015-08-01

    The construction of an imaging Stokes-polarimeter in the MAO NAS of Ukraine is proposed. It allows measuring the three components of the Stokes vector simultaneously in large FOV without restrictions on the relative aperture of the system. Moreover, the polarimeter can be converted to a low resolution spectropolarimeter by placement into optical axis of the transparence diffraction grating.

  11. [A possible correlation between "anomalous" signals in the Wheatstone bridge and positions of planets].

    Science.gov (United States)

    Sizov, A D

    2001-01-01

    Current fluctuations in diagonal of nonbalanced Wheatstone bridge were investigated. Correlations of parameters of these fluctuations with culmination times of Moon, Sun and some planet configurations were revealed. The probably biological importance of these phenomena is discussed.

  12. Comparing Infants' Preference for Correlated Audiovisual Speech with Signal-Level Computational Models

    Science.gov (United States)

    Hollich, George; Prince, Christopher G.

    2009-01-01

    How much of infant behaviour can be accounted for by signal-level analyses of stimuli? The current paper directly compares the moment-by-moment behaviour of 8-month-old infants in an audiovisual preferential looking task with that of several computational models that use the same video stimuli as presented to the infants. One type of model…

  13. Origins Space Telescope: The Far Infrared Imager and Polarimeter FIP

    Science.gov (United States)

    Staguhn, Johannes G.; Chuss, David; Howard, Joseph; Meixner, Margaret; Vieira, Joaquin; Amatucci, Edward; Bradley, Damon; Carter, Ruth; Cooray, Asantha; Flores, Anel; Leisawitz, David; Moseley, Samuel Harvey; Wollack, Edward; Origins Space Telescope Study Team

    2018-01-01

    The Origins Space Telescope (OST)* is the mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies of NASA Headquarters for the 2020 Astronomy and Astrophysics Decadal survey. The current "concept 1", which envisions a cold (4K) 9m space telescope, includes 5 instruments, providing a wavelength coverage ranging from 6um and 667um. The achievable sensitivity of the observatory will provide three to four orders of magnitude of improvement in sensitivity over current observational capabilities, allowing to address a wide range of new and so far inaccessible scientific questions, ranging from bio-signatures on exo-planets to mapping primordial H_2 from the "dark ages" before the universe went through the phase of re-ionization.Here we present the Far Infrared Imager and Polarimeter (FIP) for OST. The cameral will cover four bands, 40um, 80um, 120um, and 240um. It will allow for differential polarimetry in those bands with the ability to observe two colors in polarimtery mode simultaneously, while all four bands can be observed simultaneously in total power mode. While the confusion limit will be reached in only 32ms at 240um, at 40um the source density on the sky is so low, that at the angular resolution of 1" of OST at this wavelength there will be no source confusion, even for the longest integration times. Science topics that can be addressed by FIP include but are not limited to galactic and extragalactic magnetic field studies, Deep Galaxy Surveys, and Outer Solar System objects..*Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. We welcome you to contact the Science and Technology Definition Team (STDT) with your science needs and ideas by emailing us at ost_info@lists.ipac.caltech.edu

  14. Measurement of the nuclear polarization of hydrogen and deuterium molecules using a Lamb-shift polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Engels, Ralf, E-mail: r.w.engels@fz-juelich.de; Gorski, Robert; Grigoryev, Kiril; Mikirtychyants, Maxim; Rathmann, Frank; Seyfarth, Hellmut; Ströher, Hans; Weiss, Philipp [Institut für Kernphysik, Forschungszentrum Jülich, Wilhelm-Johnen-Str. 1, 52428 Jülich (Germany); Kochenda, Leonid; Kravtsov, Peter; Trofimov, Viktor; Tschernov, Nikolay; Vasilyev, Alexander; Vznuzdaev, Marat [Laboratory of Cryogenic and Superconductive Technique, Petersburg Nuclear Physics Institute, Orlova Roscha 1, 188300 Gatchina (Russian Federation); Schieck, Hans Paetz gen. [Institut für Kernphysik, Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany)

    2014-10-15

    Lamb-shift polarimeters are used to measure the nuclear polarization of protons and deuterons at energies of a few keV. In combination with an ionizer, the polarization of hydrogen and deuterium atoms was determined after taking into account the loss of polarization during the ionization process. The present work shows that the nuclear polarization of hydrogen or deuterium molecules can be measured as well, by ionizing the molecules and injecting the H{sub 2}{sup +} (or D{sub 2}{sup +}) ions into the Lamb-shift polarimeter.

  15. Multilayer based soft-x-ray polarimeter at MAX IV Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Grizolli, Walan; Laksman, Joakim; Hennies, Franz; Jensen, Brian Norsk; Nyholm, Ralf; Sankari, Rami, E-mail: rami.sankari@maxlab.lu.se [MAX IV Laboratory, P.O. Box 118, SE-22100 Lund (Sweden)

    2016-02-15

    A high precision five rotation-axes polarimeter using transmission multilayers as polarizers and reflection multilayers as analyzers has been designed and manufactured. To cover the extreme ultraviolet regime, Mo/Si, Cr/C, Sc/Cr, and W/B{sub 4}C multilayers for transmission and reflection have also been designed and produced. The polarimeter mechanics is supported on a hexapod to simplify the alignment relative to photon beam. The instrument is designed so that it can be easily transferred between different beamlines.

  16. Detection of sub-threshold periodic signal by multiplicative and additive cross-correlated sine-Wiener noises in the FitzHugh-Nagumo neuron

    Science.gov (United States)

    Yao, Yuangen; Ma, Chengzhang; Wang, Canjun; Yi, Ming; Gui, Rong

    2018-02-01

    We study the effects of multiplicative and additive cross-correlated sine-Wiener (CCSW) noises on the performance of sub-threshold periodic signal detection in the FitzHugh-Nagumo (FHN) neuron by calculating Fourier coefficients Q for measuring synchronization between sub-threshold input signal and the response of system. CCSW noises-induced transitions of electrical activity in the FHN neuron model can be observed. Moreover, the performance of sub-threshold periodic signal detection is achieved at moderate noise strength, cross-correlation time and cross-correlation strength of CCSW noises, which indicate the occurrence of CCSW noises-induced stochastic resonance. Furthermore, the performance of sub-threshold signal detection is strongly sensitive to cross-correlation time of CCSW noises. Therefore, the performance can be effectively controlled by regulating cross-correlation time of CCSW noises. These results provide a possible mechanism for amplifying or detecting the sub-threshold signal in the nervous system.

  17. MRI signal changes of the bone marrow in HIV-infected patients with lipodystrophy: correlation with clinical parameters

    International Nuclear Information System (INIS)

    Garcia, Ana I.; Tomas, Xavier; Pomes, Jaume; Amo, Montserrat del; Milinkovic, Ana; Perez, Inaki; Mallolas, Josep; Rios, Jose; Vidal-Sicart, Sergi

    2011-01-01

    To assess the prevalence, imaging appearance, and clinical significance, of bone marrow MR signal changes in a group of human immunodeficiency virus (HIV)-infected patients with lipodystrophy syndrome. Twenty-eight HIV-infected patients with lipodystrophy syndrome treated with highly active antiretroviral therapy, and 12 HIV-negative controls underwent MRI of the legs. Whole-body MRI, SPECT/CT, and a complete radiographic skeletal survey were obtained in subjects with signal changes in bone marrow. MRI and clinical evaluations were reviewed 6 months after baseline to determine changes after switching from thymidine analogs (TA) to tenofovir-DF (TDF). MRI results correlated with clinical parameters. We observed foci of a serous-like pattern (low signal and no enhancement on T1-weighted, high signal on T2-weighted images) in 4 out of 28 patients (14.3%) and an intermediate signal on T1-weighted images in 4 out of 28 patients (14.3%). Serous-like lesions were located in the lower limbs and scattered in the talus, calcaneus, femurs, and humeral bones; they showed slight uptake on SPECT bone scans and were normal on CT and radiographs. Patients with serous-like lesions had significantly lower peripheral and total fat at baseline than other groups (P < 0.05). No changes at 6 months were observed on MRI, and the serous-like lesion group showed good peripheral fat recovery after changing drug treatment. A serous-like MRI pattern is observed in the peripheral skeletons of HIV-infected patients with lipodystrophy, which correlates with peripheral lipoatrophy, and should not be misdiagnosed as malignant or infectious diseases. Although the MR lesions did not improve after switching the treatment, there was evidence of lipoatrophy recovery. (orig.)

  18. Remote Sensing of Cloud Top Heights Using the Research Scanning Polarimeter

    Science.gov (United States)

    Sinclair, Kenneth; van Diedenhoven, Bastiaan; Cairns, Brian; Yorks, John; Wasilewski, Andrzej

    2015-01-01

    Clouds cover roughly two thirds of the globe and act as an important regulator of Earth's radiation budget. Of these, multilayered clouds occur about half of the time and are predominantly two-layered. Changes in cloud top height (CTH) have been predicted by models to have a globally averaged positive feedback, however observational changes in CTH have shown uncertain results. Additional CTH observations are necessary to better and quantify the effect. Improved CTH observations will also allow for improved sub-grid parameterizations in large-scale models and accurate CTH information is important when studying variations in freezing point and cloud microphysics. NASA's airborne Research Scanning Polarimeter (RSP) is able to measure cloud top height using a novel multi-angular contrast approach. RSP scans along the aircraft track and obtains measurements at 152 viewing angles at any aircraft location. The approach presented here aggregates measurements from multiple scans to a single location at cloud altitude using a correlation function designed to identify the location-distinct features in each scan. During NASAs SEAC4RS air campaign, the RSP was mounted on the ER-2 aircraft along with the Cloud Physics Lidar (CPL), which made simultaneous measurements of CTH. The RSPs unique method of determining CTH is presented. The capabilities of using single and combinations of channels within the approach are investigated. A detailed comparison of RSP retrieved CTHs with those of CPL reveal the accuracy of the approach. Results indicate a strong ability for the RSP to accurately identify cloud heights. Interestingly, the analysis reveals an ability for the approach to identify multiple cloud layers in a single scene and estimate the CTH of each layer. Capabilities and limitations of identifying single and multiple cloud layers heights are explored. Special focus is given to sources of error in the method including optically thin clouds, physically thick clouds, multi

  19. Correlation functions and power spectra of Doppler response signals in ultrasonic medical applications.

    Science.gov (United States)

    Skresanova, Iryna V; Barannik, Evgen A

    2012-07-01

    Ultrasound Doppler methods are widely used in clinical practice as prospective investigational tool to study the vascular system and soft biological tissues. Meanwhile, the most general relationship between the power Doppler spectra, spectral characteristics of the scattering fluctuations and the probing ultrasound field parameters for some clinical implementations are still unexplored. Based upon the continuum model of scattering inhomogeneities, a set of the closed-form expressions for the correlation functions and the spectra of Doppler response of soft tissues and blood have been derived. The influence of the correlation among inhomogeneities and the diffusion processes on the Doppler power spectra formed by stationary flows have been examined. Computer simulations of Doppler spectra were performed for different values of correlation radius and diffusion coefficient. With simulation results the effects of the correlation among inhomogeneities and the diffusion processes on the spectral width and mean frequency are established and discussed in respect to turbulent flows. Closed-form expressions for correlation functions and Doppler spectra for the vibrational sonoelastography technique for visualizing malignant tumors in tissues have been derived. Based on the peculiarities of the obtained Doppler spectra, it is shown that the differentiation of soft tissues with respect to the amplitude value of constrained oscillations is feasible. The expressions were derived for the cases of non-stationary accelerated blood movement. It has been found that the frequency dependence reveals solely at a finite time of observation and depends on the initial phase of the accelerated movement. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Time dependent auto-correlation, autospectrum and decay ratio estimation of transient signals in JET soft X-ray records

    International Nuclear Information System (INIS)

    Por, G.

    1999-08-01

    A program package was developed to estimate the time dependent auto-correlation function (ACF) from the time signals of soft X-ray records taken along the various lines-of-sights in JET-SHOTS, and also to estimate the time dependent Decay Ratio (DR) from that. On the basis of ACF the time dependent auto-power spectral density (APSD) was also calculated. The steps and objectives of this work were: eliminating the white detection noise, trends and slow variation from the time signals, since ordinary methods can give good estimate of the time dependent ACF and DR only for 'nearly' stationary signals, developing an automatic algorithm for finding the maxima and minima of ACF, since they are the basis for DR estimation, evaluating and testing different DR estimators for JET-SHOT, with the aim of finding parts of the signals, where the oscillating character is strong, estimating time dependent ACF and APSD that can follow the relatively fast variation in the time signal. The methods that we have developed for data processing of transient signals are: White detection noise removal and preparation for trend removal - weak components, white detection noise and high frequency components are filtered from the signal using the so-called soft-threshold wavelet filter. Removal of trends and slow variation - Three-point differentiation of the pre-filtered signal is used to remove trends and slow variation. Here we made use of the DERIV function of IDL program language. This leads to a filtered signal that has zero mean value in each time step. Calculation of the time dependent ACF - The signal treated by the two previous steps is used as the input. Calculated ACF value is added in each new time step, but the previously accumulated ACF value is multiplied by a weighting factor. Thus the new sample has 100% contribution, while the contributions from the previous samples are forgotten quickly. DR calculation - DR is a measure of the decay of oscillating ACF. This parameter was shown

  1. Correlation between the electric and acoustic signals emitted during compression of brittle materials

    Directory of Open Access Journals (Sweden)

    Ermioni D. Pasiou

    2017-04-01

    Full Text Available An experimental protocol is described including a series of uni¬axial compression tests of three brittle materials (marble, mortar and glass. The Acoustic Emission (AE technique and the Pressure Stimulated Currents (PSC one are used since the recordings of both techniques are strongly related to the formation of cracking in brittle materials. In the present paper, the correlation of these techniques is investigated, which is finally proven to be very satisfactory.

  2. SOLPOL: A Solar Polarimeter for Hard X-Rays and Gamma-Rays

    Science.gov (United States)

    McConnell, Michael L.

    1999-01-01

    Th goal of this project was to continue the development of a hard X-ray polarimeter for studying solar flares. In earlier work (funded by a previous SR&T grant), we had already achieved several goals, including the following: 1) development of a means of producing a polarized radiation source in the lab that could be used for prototype development; 2) demonstrated the basic Compton scatter polarimeter concept using a simple laboratory setup; 3) used the laboratory results to verify our Monte Carlo simulations; and 4) investigated various detector technologies that could be incorporated into the polarimeter design. For the current one-year program, we wanted to fabricate and test a laboratory science model based on our SOLPOL (Solar Polarimeter) design. The long-term goal of this effort is to develop and test a prototype design that could be used to study flare emissions from either a balloon- or space-borne platform. The current program has achieved its goal of fabricating and testing a science model of the SOLPOL design, although additional testing of the design (and detailed comparison with Monte Carlo simulations) is still desired. This one-year program was extended by six months (no-cost extension) to cover the summer of 1999, when undergraduate student support was available to complete some of the laboratory testing.

  3. The ZIMPOL high-contrast imaging polarimeter for SPHERE: design, manufacturing, and testing

    NARCIS (Netherlands)

    Roelfsema, R.; Schmid, H.M.; Pragt, J.; Gisler, D.; Waters, R.; Bazzon, A.; Baruffolo, A.; Beuzit, J.-L.; Boccaletti, A.; Charton, J.; Cumani, C.; Dohlen, K.; Downing, M.; Elswijk, E.; Feldt, M.; Groothuis, C.; de Haan, M.; Hanenburg, H.; Hubin, N.; Joos, F.; Kasper, M.; Keller, C.; Kragt, J.; Lizon, J.-L.; Mouillet, D.; Pavlov, A.; Rigal, F.; Rochat, S.; Salasnich, B.; Steiner, P.; Thalmann, C.; Venema, L.; Wildi, F.

    2010-01-01

    ZIMPOL is the high contrast imaging polarimeter subsystem of the ESO SPHERE instrument. ZIMPOL is dedicated to detect the very faint reflected and hence polarized visible light from extrasolar planets. ZIMPOL is located behind an extreme AO system (SAXO) and a stellar coronagraph. SPHERE is foreseen

  4. SHARP: The SHARC-II polarimeter at the Caltech Submillimeter Observatory

    Science.gov (United States)

    Vaillancourt, John E.; Attard, M.; Dowell, C. D.; Hildebrand, R. H.; Houde, M.; Kirby, L.; Krejny, M.; Li, H.; Novak, G.; Shinnaga, H.

    2006-12-01

    The Submillimeter High Angular Resolution Camera II (SHARC-II) is a 12 × 32 pixel camera used with the 10 meter diameter Caltech Submillimeter Observatory (CSO). We have deployed an optics module between the telescope and camera which converts SHARC-II into a sensitive imaging polarimeter, "SHARP." The camera and polarimeter currently operate at wavelengths of 350 and 450 μm we are planning an additional passband at 620 μm. The incident beam is split into two orthogonally polarized components by the SHARP optics module and re-imaged onto opposite ends of the SHARC-II array. The result is a dual-beam 12 × 12 pixel polarimeter. The modular nature of the optics design allows the user to easily switch between polarimeter and camera modes during a single observing session. Here we review the optical design of SHARP, report on the instrument's performance, and review our data reduction methodology. SHARP will be used to study the magnetic field structure and dust emission properties in young stellar objects, Galactic clouds, and external galaxies. We present the first polarimetric maps of celestial sources made from SHARP observations and compare them to previous results. This work has been supported by NSF grants AST 02-41356 and 05-05230 to Northwestern University and 05-05124 to the University of Chicago.

  5. Exploring a possible origin of a 14 deg y-normal spin tilt at RHIC polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-06-15

    A possible origin of a 14 deg y-normal spin n0 tilt at the polarimeter is in snake angle defects. This possible cause is investigated by scanning the snake axis angle µ, and the spin rotation angle at the snake, φ, in the vicinity of their nominal values.

  6. Robust Frame Synchronization for Low Signal-to-Noise Ratio Channels Using Energy-Corrected Differential Correlation

    Directory of Open Access Journals (Sweden)

    Kim Pansoo

    2009-01-01

    Full Text Available Recent standards for wireless transmission require reliable synchronization for channels with low signal-to-noise ratio (SNR as well as with a large amount of frequency offset, which necessitates a robust correlator structure for the initial frame synchronization process. In this paper, a new correlation strategy especially targeted for low SNR regions is proposed and its performance is analyzed. By utilizing a modified energy correction term, the proposed method effectively reduces the variance of the decision variable to enhance the detection performance. Most importantly, the method is demonstrated to outperform all previously reported schemes by a significant margin, for SNRs below 5 dB regardless of the existence of the frequency offsets. A variation of the proposed method is also presented for further enhancement over the channels with small frequency errors. The particular application considered for the performance verification is the second generation digital video broadcasting system for satellites (DVB-S2.

  7. Iron accumulation in deep cortical layers accounts for MRI signal abnormalities in ALS: correlating 7 tesla MRI and pathology.

    Directory of Open Access Journals (Sweden)

    Justin Y Kwan

    Full Text Available Amyotrophic lateral sclerosis (ALS is a progressive neurodegenerative disorder characterized by cortical and spinal motor neuron dysfunction. Routine magnetic resonance imaging (MRI studies have previously shown hypointense signal in the motor cortex on T(2-weighted images in some ALS patients, however, the cause of this finding is unknown. To investigate the utility of this MR signal change as a marker of cortical motor neuron degeneration, signal abnormalities on 3T and 7T MR images of the brain were compared, and pathology was obtained in two ALS patients to determine the origin of the motor cortex hypointensity. Nineteen patients with clinically probable or definite ALS by El Escorial criteria and 19 healthy controls underwent 3T MRI. A 7T MRI scan was carried out on five ALS patients who had motor cortex hypointensity on the 3T FLAIR sequence and on three healthy controls. Postmortem 7T MRI of the brain was performed in one ALS patient and histological studies of the brains and spinal cords were obtained post-mortem in two patients. The motor cortex hypointensity on 3T FLAIR images was present in greater frequency in ALS patients. Increased hypointensity correlated with greater severity of upper motor neuron impairment. Analysis of 7T T(2(*-weighted gradient echo imaging localized the signal alteration to the deeper layers of the motor cortex in both ALS patients. Pathological studies showed increased iron accumulation in microglial cells in areas corresponding to the location of the signal changes on the 3T and 7T MRI of the motor cortex. These findings indicate that the motor cortex hypointensity on 3T MRI FLAIR images in ALS is due to increased iron accumulation by microglia.

  8. From correlation to causation: Estimating effective connectivity from zero-lag covariances of brain signals.

    Science.gov (United States)

    Schiefer, Jonathan; Niederbühl, Alexander; Pernice, Volker; Lennartz, Carolin; Hennig, Jürgen; LeVan, Pierre; Rotter, Stefan

    2018-03-01

    Knowing brain connectivity is of great importance both in basic research and for clinical applications. We are proposing a method to infer directed connectivity from zero-lag covariances of neuronal activity recorded at multiple sites. This allows us to identify causal relations that are reflected in neuronal population activity. To derive our strategy, we assume a generic linear model of interacting continuous variables, the components of which represent the activity of local neuronal populations. The suggested method for inferring connectivity from recorded signals exploits the fact that the covariance matrix derived from the observed activity contains information about the existence, the direction and the sign of connections. Assuming a sparsely coupled network, we disambiguate the underlying causal structure via L1-minimization, which is known to prefer sparse solutions. In general, this method is suited to infer effective connectivity from resting state data of various types. We show that our method is applicable over a broad range of structural parameters regarding network size and connection probability of the network. We also explored parameters affecting its activity dynamics, like the eigenvalue spectrum. Also, based on the simulation of suitable Ornstein-Uhlenbeck processes to model BOLD dynamics, we show that with our method it is possible to estimate directed connectivity from zero-lag covariances derived from such signals. In this study, we consider measurement noise and unobserved nodes as additional confounding factors. Furthermore, we investigate the amount of data required for a reliable estimate. Additionally, we apply the proposed method on full-brain resting-state fast fMRI datasets. The resulting network exhibits a tendency for close-by areas being connected as well as inter-hemispheric connections between corresponding areas. In addition, we found that a surprisingly large fraction of more than one third of all identified connections were of

  9. Revealing the Eruptive History of Volcanoes from Massive Cross-Correlation of Seismic Signal at Global Scale

    Science.gov (United States)

    Dupont, A.; Gaillard, P.; Grenouille, A.; Bui-Quang, P.; Guilhem, A.; Bobrov, D.; Kitov, I. O.; Rozhkov, M.

    2015-12-01

    We propose here a massive cross-correlation technique applied to seismic events located around volcanoes and recorded at teleseismic distance. Multichannel cross-correlations are performed between 2002 to 2012 using seismic templates occurring at the time of moderate to large volcanic eruptions. The volcanic periods are reported from the Global Volcanism Program database while the waveform data are obtained from the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). The temporal distribution of new seismic events, built from the association of teleseismic detections reveals acceleration patterns, which are highly correlated to the past eruptive activities. These newly detected events are relocated using Bayesian approach and leads to preliminary interpretation of the volcanic plumbing system. Two examples are presented. First, the large 2008 eruption (Volcanic Explosivity Index, VEI4) of Kasatochi (Aleutian Islands, 52.10°N/175.31°W) is used to demonstrate that only few seismic templates (~3) help to reveal the time scale of the eruption. Results are compared to hydroacoustic signal, which is highly correlated to the distribution of new seismic events prior and during eruption. We also show that after the peaked seismic activity (i.e., ~ 100 seismic events in 1 hour) the infrasound signal starts and signs the volcanic plume activity. The second case example reveals with success seven past volcanic eruptions of lower magnitude (VEI1 to VEI2) of the Karangetang volcano (Siau Island in Indonesia, 2.46°N/125.24°E). We show the potential of this method to detect volcanic eruptions in isolated areas. This is of special interest especially when there is no volcano observatory to monitor the volcanic activity, or when the last eruptive period is unknown.

  10. Real-time algorithm for the measurement of liquid metal coolant flow velocity with correlated thermal signals

    International Nuclear Information System (INIS)

    Moazzeni, Taleb; Jiang, Yingtao; Ma, Jian; Li, Ning

    2009-01-01

    One flow meter was developed especially for the environment of high irradiation, pressure, and temperature. The transit time of natural random temperature fluctuation in process, for example nuclear reactor, can be obtained based on the cross-correlation method, which has already been shown that it is capable in situations where no other flow meter can be used. Thereby, the flow rate can be derived in pipe flow if the area of cross-section is known. In practice, the evaluation of the integrals over the measurement time in cross-correlation method will lead errors caused by peak detection from flat cross correlation coefficient distribution or additional peaks. One Auto-Adaptive Impulse Response Function estimation is introduced and significantly narrower peak will be obtained. Fiber optic sensors are advantageous for temperature measurements in the reactor pressure vessels. However, the corrosive coolant (as liquid lead/lead alloy or molten salt coolant) is a barrier of the optic sensor in such application. Thermocouple with grounded stainless steel shielding material would have same life time with structure material in reactor, although thermocouple has relatively slow response. The degradation due to corrosion/erosion will not introduce measurement error or necessary calibration, because only the correlation between signals is taken into consideration during measurements. Experiments conducted in a testing hydraulic facility approved the considerable improvement of accuracy by this new algorithm using thermocouple temperature sensors. (author)

  11. Correlation-Based Amplitude Estimation of Coincident Partials in Monaural Musical Signals

    Directory of Open Access Journals (Sweden)

    Jayme Garcia Arnal Barbedo

    2010-01-01

    Full Text Available This paper presents a method for estimating the amplitude of coincident partials generated by harmonic musical sources (instruments and vocals. It was developed as an alternative to the commonly used interpolation approach, which has several limitations in terms of performance and applicability. The strategy is based on the following observations: (a the parameters of partials vary with time; (b such a variation tends to be correlated when the partials belong to the same source; (c the presence of an interfering coincident partial reduces the correlation; and (d such a reduction is proportional to the relative amplitude of the interfering partial. Besides the improved accuracy, the proposed technique has other advantages over its predecessors: it works properly even if the sources have the same fundamental frequency, it is able to estimate the first partial (fundamental, which is not possible using the conventional interpolation method, it can estimate the amplitude of a given partial even if its neighbors suffer intense interference from other sources, it works properly under noisy conditions, and it is immune to intraframe permutation errors. Experimental results show that the strategy clearly outperforms the interpolation approach.

  12. Correlation methods for the analysis of X-ray polarimetric signals

    Science.gov (United States)

    Massaro, E.; Fabiani, S.; Campana, R.; Costa, E.; Del Monte, E.; Muleri, F.; Soffitta, P.

    2018-03-01

    X-ray polarimetric measurements are based on studying the distribution of the directions of scattered photons or photoelectrons and on the search of a sinusoidal modulation with a period of π. We developed two tools for investigating these angular distributions based on the correlations between counts in phase bins separated by fixed phase distances. In one case we use the correlation between data separated by half of the bin number (one period) which is expected to give a linear pattern. In the other case, the scatter plot obtained by shifting by 1/8 of the bin number (1/4 of period) transforms the sinusoid in a circular pattern whose radius is equal to the amplitude of the modulation. For unpolarized radiation these plots are reduced to a random point distribution centred at the mean count level. This new methods provide direct visual and simple statistical tools for evaluating the quality of polarization measurements and for estimating the polarization parameters. Furthermore they are useful for investigating distortions due to systematic effects.

  13. Adiposity and postural balance control: correlations between bioelectrical impedance and stabilometric signals in elderly Brazilian women

    Directory of Open Access Journals (Sweden)

    Míriam Raquel Meira Mainenti

    2011-01-01

    Full Text Available OBJECTIVE: The purpose of this study was to investigate the correlation between body adiposity and postural control in elderly women. INTRODUCTION: Aging and obesity account for a significant portion of healthcare spending. Life expectancy is increasing worldwide, and Rio de Janeiro has the largest proportion of elderly residents of all Brazilian states. METHODS: A total of 45 women underwent bioelectrical impedance analysis, waist circumference measurements, weight and height measurements, and stabilometric tests in eight different stance conditions (opened and closed bases with both eyes opened and closed and right and left tandem and unilateral stances with eyes opened. During unilateral stances, the number of hand or foot contacts was counted. RESULTS: Weight, body mass index, waist circumference, fat percentage, and fat mass showed statistically significant (p,0.05 and positive correlations with the number of contacts made during unilateral stances. The subjects with greater fat mass showed significantly higher anterior-posterior standard deviation and range when their eyes were closed. The sway area was also greater for this group in opened base when their eyes were closed. DISCUSSION: The results relating body adiposity and postural control can be explained by the difficulty of maintaining a greater quantity of body fat mass within the limits of the individual support base, especially while assuming a unilateral stance. CONCLUSION: The subjects with a greater fat mass exhibited poor balance control, indicating that body adiposity level was associated with postural control in the elderly women examined in the present study.

  14. Adiposity and postural balance control: Correlations between bioelectrical impedance and stabilometric signals in elderly Brazilian women

    Science.gov (United States)

    Mainenti, Míriam Raquel Meira; de Carvalho Rodrigues, Érika; de Oliveira, Juliana Flávia; de Sá Ferreira, Arthur; Dias, Cristina Márcia; dos Santos Silva, André Luís

    2011-01-01

    OBJECTIVE: The purpose of this study was to investigate the correlation between body adiposity and postural control in elderly women. INTRODUCTION: Aging and obesity account for a significant portion of healthcare spending. Life expectancy is increasing worldwide, and Rio de Janeiro has the largest proportion of elderly residents of all Brazilian states. METHODS: A total of 45 women underwent bioelectrical impedance analysis, waist circumference measurements, weight and height measurements, and stabilometric tests in eight different stance conditions (opened and closed bases with both eyes opened and closed and right and left tandem and unilateral stances with eyes opened). During unilateral stances, the number of hand or foot contacts was counted. RESULTS: Weight, body mass index, waist circumference, fat percentage, and fat mass showed statistically significant (p<0.05) and positive correlations with the number of contacts made during unilateral stances. The subjects with greater fat mass showed significantly higher anterior-posterior standard deviation and range when their eyes were closed. The sway area was also greater for this group in opened base when their eyes were closed. DISCUSSION: The results relating body adiposity and postural control can be explained by the difficulty of maintaining a greater quantity of body fat mass within the limits of the individual support base, especially while assuming a unilateral stance. CONCLUSION: The subjects with a greater fat mass exhibited poor balance control, indicating that body adiposity level was associated with postural control in the elderly women examined in the present study. PMID:22179151

  15. Correlating phosphoproteomic signaling with castration resistant prostate cancer survival through regression analysis.

    Science.gov (United States)

    Lescarbeau, Reynald; Kaplan, David L

    2014-03-04

    Prostate cancer most commonly presents as initially castration dependent, however in a minority of patients the disease will progress to a state of castration resistance. Here, approaches for correlating alterations in the phosphoproteome with androgen independent cell survival in the LNCaP, PC3, and MDa-PCa-2b cell lines are discussed. The performance of the regression techniques multiple linear, ridge, principal component, and partial least squares regression is compared. The predictive performance of these algorithms over randomized data sets and using the Akaike Information Criterion is explored, and principal component and partial least squares regression are found to outperform other regression approaches. The effect of altering the number of features versus observations on the R(2) value and predictive performance is also examined using the partial least squares regression model. Utilizing these approaches "drivers" of castration resistant disease can be identified whose modulation alters phenotypic outcomes. These data provide an empirical comparison of the various considerations when statistically analyzing phosphorylation data with the aim of correlating with phenotypic outcomes.

  16. The expression of ER, PR in endometrial cancer and analysis of their correlation with ERK signaling pathway.

    Science.gov (United States)

    Luo, Lan; Xu, Lina; Tang, Liang

    2017-12-12

    Endometrial carcinoma (EC) is a common malignant tumor in gynecology. Its incidence and development are closely associated with the levels of estrogenic and progesterone hormone. Extracellular signal-regulated kinase (ERK) signaling pathway abnormity is associated with a variety of tumors. This study detected estrogen receptor (ER), progesterone receptor (PR), ERK1, and ERK2 expression in EC and analyzed their correlations. A total of 40 EC patients in our hospital were selected as test group, while another 40 healthy volunteers were enrolled as control group. ER, PR, ERK1, and ERK2 expression in EC tissue, para-carcinoma tissue, and normal endometrial tissue were detected by immunohistochemistry and Western blot. The positive rate of ER, PR, ERK1, and ERK2 in the test group was 50%, 40%, 60%, and 65%, respectively, which were significantly higher than those in the control (PPR, ERK1, and ERK2 protein expressions in EC cell were significantly higher than those in the control (PPR (PPR, which were correlated with higher levels of ERK1 and ERK2, suggesting they might be involved in the pathogenesis of EC.

  17. Correlative Evaluation of Mental and Physical Workload of Laparoscopic Surgeons Based on Surface Electromyography and Eye-tracking Signals.

    Science.gov (United States)

    Zhang, Jian-Yang; Liu, Sheng-Lin; Feng, Qing-Min; Gao, Jia-Qi; Zhang, Qiang

    2017-09-11

    Surgeons' mental and physical workloads are major focuses of operating room (OR) ergonomics, and studies on this topic have generally focused on either mental workload or physical workload, ignoring the interaction between them. Previous studies have shown that physically demanding work may affect mental performance and may be accompanied by impaired mental processing and decreased performance. In this study, 14 participants were recruited to perform laparoscopic cholecystectomy (LC) procedures in a virtual simulator. Surface electromyography (sEMG) signals of the bilateral trapezius, bicipital, brachioradialis and flexor carpi ulnaris (FCU) muscles and eye-tracking signals were acquired during the experiment. The results showed that the least square means of muscle activity during the LC phases of surgery in an all-participants mixed effects model were 0.79, 0.81, and 0.98, respectively. The observed muscle activities in the different phases exhibited some similarity, while marked differences were found between the forearm bilateral muscles. Regarding mental workload, significant differences were observed in pupil dilation between the three phases of laparoscopic surgery. The mental and physical workloads of laparoscopic surgeons do not appear to be generally correlated, although a few significant negative correlations were found. This result further indicates that mental fatigue does markedly interfere with surgeons' operating movements.

  18. Evolution of Diffusion-Weighted Magnetic Resonance Imaging Signal Abnormality in Sporadic Creutzfeldt-Jakob Disease, With Histopathological Correlation.

    Science.gov (United States)

    Eisenmenger, Laura; Porter, Marie-Claire; Carswell, Christopher J; Thompson, Andrew; Mead, Simon; Rudge, Peter; Collinge, John; Brandner, Sebastian; Jäger, Hans R; Hyare, Harpreet

    2016-01-01

    Prion diseases represent the archetype of brain diseases caused by protein misfolding, with the most common subtype being sporadic Creutzfeldt-Jakob disease (sCJD), a rapidly progressive dementia. Diffusion-weighted imaging (DWI) has emerged as the most sensitive magnetic resonance imaging (MRI) sequence for the diagnosis of sCJD, but few studies have assessed the evolution of MRI signal as the disease progresses. To assess the natural history of the MRI signal abnormalities on DWI in sCJD to improve our understanding of the pathogenesis and to investigate the potential of DWI as a biomarker of disease progression, with histopathological correlation. Gray matter involvement on DWI was assessed among 37 patients with sCJD in 26 cortical and 5 subcortical subdivisions per hemisphere using a semiquantitative scoring system of 0 to 2 at baseline and follow-up. A total brain score was calculated as the summed scores in the individual regions. In 7 patients, serial mean diffusivity measurements were obtained. Age at baseline MRI, disease duration, atrophy, codon 129 methionine valine polymorphism, Medical Research Council Rating Scale score, and histopathological findings were documented. The study setting was the National Prion Clinic, London, England. All participants had a probable or definite diagnosis of sCJD and had at least 2 MRI studies performed during the course of their illness. The study dates were October 1, 2008 to April 1, 2012. The dates of our analysis were January 19 to April 20, 2012. Correlation of regional and total brain scores with disease duration. Among the 37 patients with sCJD in this study there was a significant increase in the number of regions demonstrating signal abnormality during the study period, with 59 of 62 regions showing increased signal intensity (SI) at follow-up, most substantially in the caudate and putamen (P disease duration (r = 0.47, P = .003 at baseline and r = 0.35, P = .03 at follow-up), and the left

  19. Multiphasic On/Off Pheromone Signalling in Moths as Neural Correlates of a Search Strategy

    Science.gov (United States)

    Martinez, Dominique; Chaffiol, Antoine; Voges, Nicole; Gu, Yuqiao; Anton, Sylvia; Rospars, Jean-Pierre; Lucas, Philippe

    2013-01-01

    Insects and robots searching for odour sources in turbulent plumes face the same problem: the random nature of mixing causes fluctuations and intermittency in perception. Pheromone-tracking male moths appear to deal with discontinuous flows of information by surging upwind, upon sensing a pheromone patch, and casting crosswind, upon losing the plume. Using a combination of neurophysiological recordings, computational modelling and experiments with a cyborg, we propose a neuronal mechanism that promotes a behavioural switch between surge and casting. We show how multiphasic On/Off pheromone-sensitive neurons may guide action selection based on signalling presence or loss of the pheromone. A Hodgkin-Huxley-type neuron model with a small-conductance calcium-activated potassium (SK) channel reproduces physiological On/Off responses. Using this model as a command neuron and the antennae of tethered moths as pheromone sensors, we demonstrate the efficiency of multiphasic patterning in driving a robotic searcher toward the source. Taken together, our results suggest that multiphasic On/Off responses may mediate olfactory navigation and that SK channels may account for these responses. PMID:23613816

  20. Multiphasic on/off pheromone signalling in moths as neural correlates of a search strategy.

    Directory of Open Access Journals (Sweden)

    Dominique Martinez

    Full Text Available Insects and robots searching for odour sources in turbulent plumes face the same problem: the random nature of mixing causes fluctuations and intermittency in perception. Pheromone-tracking male moths appear to deal with discontinuous flows of information by surging upwind, upon sensing a pheromone patch, and casting crosswind, upon losing the plume. Using a combination of neurophysiological recordings, computational modelling and experiments with a cyborg, we propose a neuronal mechanism that promotes a behavioural switch between surge and casting. We show how multiphasic On/Off pheromone-sensitive neurons may guide action selection based on signalling presence or loss of the pheromone. A Hodgkin-Huxley-type neuron model with a small-conductance calcium-activated potassium (SK channel reproduces physiological On/Off responses. Using this model as a command neuron and the antennae of tethered moths as pheromone sensors, we demonstrate the efficiency of multiphasic patterning in driving a robotic searcher toward the source. Taken together, our results suggest that multiphasic On/Off responses may mediate olfactory navigation and that SK channels may account for these responses.

  1. Auto-correlation in the motor/imaginary human EEG signals: A vision about the FDFA fluctuations.

    Science.gov (United States)

    Zebende, Gilney Figueira; Oliveira Filho, Florêncio Mendes; Leyva Cruz, Juan Alberto

    2017-01-01

    In this paper we analyzed, by the FDFA root mean square fluctuation (rms) function, the motor/imaginary human activity produced by a 64-channel electroencephalography (EEG). We utilized the Physionet on-line databank, a publicly available database of human EEG signals, as a standardized reference database for this study. Herein, we report the use of detrended fluctuation analysis (DFA) method for EEG analysis. We show that the complex time series of the EEG exhibits characteristic fluctuations depending on the analyzed channel in the scalp-recorded EEG. In order to demonstrate the effectiveness of the proposed technique, we analyzed four distinct channels represented here by F332, F637 (frontal region of the head) and P349, P654 (parietal region of the head). We verified that the amplitude of the FDFA rms function is greater for the frontal channels than for the parietal. To tabulate this information in a better way, we define and calculate the difference between FDFA (in log scale) for the channels, thus defining a new path for analysis of EEG signals. Finally, related to the studied EEG signals, we obtain the auto-correlation exponent, αDFA by DFA method, that reveals self-affinity at specific time scale. Our results shows that this strategy can be applied to study the human brain activity in EEG processing.

  2. Auto-correlation in the motor/imaginary human EEG signals: A vision about the FDFA fluctuations.

    Directory of Open Access Journals (Sweden)

    Gilney Figueira Zebende

    Full Text Available In this paper we analyzed, by the FDFA root mean square fluctuation (rms function, the motor/imaginary human activity produced by a 64-channel electroencephalography (EEG. We utilized the Physionet on-line databank, a publicly available database of human EEG signals, as a standardized reference database for this study. Herein, we report the use of detrended fluctuation analysis (DFA method for EEG analysis. We show that the complex time series of the EEG exhibits characteristic fluctuations depending on the analyzed channel in the scalp-recorded EEG. In order to demonstrate the effectiveness of the proposed technique, we analyzed four distinct channels represented here by F332, F637 (frontal region of the head and P349, P654 (parietal region of the head. We verified that the amplitude of the FDFA rms function is greater for the frontal channels than for the parietal. To tabulate this information in a better way, we define and calculate the difference between FDFA (in log scale for the channels, thus defining a new path for analysis of EEG signals. Finally, related to the studied EEG signals, we obtain the auto-correlation exponent, αDFA by DFA method, that reveals self-affinity at specific time scale. Our results shows that this strategy can be applied to study the human brain activity in EEG processing.

  3. Correlation of radiation induced cellular signal transduction events with LET-selective thermoluminescence dosimetry

    International Nuclear Information System (INIS)

    Fuerweger, C.; Hajek, M.; Vana, N.; Kodym, R.; Okayasu, Ryuichi

    2006-01-01

    In order to obtain a deeper insight into the molecular mechanism controlling the cellular response to high-linear energy transfer (LET) radiation we observed early signal transduction events after low dose exposure to charged particles. Normal human fibroblasts were irradiated with ions of varying energy and LET (Helium, Carbon, Neon, Silicon and Iron, from 2, 2 up to 300 keV/μm) at the National Institute of Radiological Sciences (NIRS)-Heavy Ion Medical Accelerator in Chiba (HIMAC)-facility. For exposure, a low particle fluence of approx. 7, 3 * 10 4 particles/cm 2 (corresponding to 1 hit nucleus in 7 cells) was chosen. Doses and LET were verified with thermoluminescence detectors (LiF: Mg, Ti) evaluated according to the high-temperature-ratio (HTR)-method. In FY 2005, we focused on investigating the activation of ataxia telangiectasia mutated (ATM) and several of its substrates 2-3 hours after irradiation using immunofluorescence and immunohistochemical staining techniques. So far, we found that the number of pATM (S1981)-foci per nucleus was higher in cells irradiated with higher-LET beams. Especially Fe-ions (500 MeV/u) yielded twice the number of foci than mock or He (150 MeV/u) irradiated cells. Furthermore, for Fe-ions the number of cells with radiation induced γH2aX-foci exceeded the number of cells with nucleus hits, indicating a bystander effect. These data show that the early cellular response to high-LET radiation is modulated by the energy deposition of the particle. (author)

  4. Correlation of pre-earthquake electromagnetic signals with laboratory and field rock experiments

    Directory of Open Access Journals (Sweden)

    T. Bleier

    2010-09-01

    rock stressing results and the 30 October 2007 M5.4 Alum Rock earthquake field data.

    The second part of this paper examined other California earthquakes, prior to the Alum Rock earthquake, to see if magnetic pulsations were also present prior to those events. A search for field examples of medium earthquakes was performed to identify earthquakes where functioning magnetometers were present within 20 km, the expected detection range of the magnetometers. Two earthquakes identified in the search included the 12 August 1998 M5.1 San Juan Bautista (Hollister Ca. earthquake and the 28 September 2004 M6.0 Parkfield Ca. earthquake. Both of these data sets were recorded using EMI Corp. Model BF4 induction magnetometers, installed in equipment owned and operated by UC Berkeley. Unfortunately, no air conductivity or IR data were available for these earthquake examples. This new analysis of old data used the raw time series data (40 samples per s, and examined the data for short duration pulsations that exceeded the normal background noise levels at each site, similar to the technique used at Alum Rock. Analysis of Hollister magnetometer, positioned 2 km from the epicenter, showed a significant increase in magnetic pulsations above quiescient threshold levels several weeks prior, and especially 2 days prior to the quake. The pattern of positive and negative pulsations observed at Hollister, were similar, but not identical to Alum Rock in that the pattern of pulsations were interspersed with Pc 1 pulsation trains, and did not start 2 weeks prior to the quake, but rather 2 days prior. The Parkfield data (magnetometer positioned 19 km from the epicenter showed much smaller pre-earthquake pulsations, but the area had significantly higher conductivity (which attenuates the signals. More interesting was the fact that significant pulsations occurred between the aftershock sequences of quakes as the crustal stress patterns were migrating.

    Comparing

  5. Correlation of pre-earthquake electromagnetic signals with laboratory and field rock experiments

    Science.gov (United States)

    Bleier, T.; Dunson, C.; Alvarez, C.; Freund, F.; Dahlgren, R.

    2010-09-01

    October 2007 M5.4 Alum Rock earthquake field data. The second part of this paper examined other California earthquakes, prior to the Alum Rock earthquake, to see if magnetic pulsations were also present prior to those events. A search for field examples of medium earthquakes was performed to identify earthquakes where functioning magnetometers were present within 20 km, the expected detection range of the magnetometers. Two earthquakes identified in the search included the 12 August 1998 M5.1 San Juan Bautista (Hollister Ca.) earthquake and the 28 September 2004 M6.0 Parkfield Ca. earthquake. Both of these data sets were recorded using EMI Corp. Model BF4 induction magnetometers, installed in equipment owned and operated by UC Berkeley. Unfortunately, no air conductivity or IR data were available for these earthquake examples. This new analysis of old data used the raw time series data (40 samples per s), and examined the data for short duration pulsations that exceeded the normal background noise levels at each site, similar to the technique used at Alum Rock. Analysis of Hollister magnetometer, positioned 2 km from the epicenter, showed a significant increase in magnetic pulsations above quiescient threshold levels several weeks prior, and especially 2 days prior to the quake. The pattern of positive and negative pulsations observed at Hollister, were similar, but not identical to Alum Rock in that the pattern of pulsations were interspersed with Pc 1 pulsation trains, and did not start 2 weeks prior to the quake, but rather 2 days prior. The Parkfield data (magnetometer positioned 19 km from the epicenter) showed much smaller pre-earthquake pulsations, but the area had significantly higher conductivity (which attenuates the signals). More interesting was the fact that significant pulsations occurred between the aftershock sequences of quakes as the crustal stress patterns were migrating. Comparing laboratory, field experiments with a boulder, and earthquake events

  6. Correlation of SO2 Gas Emissions, Seismicity and Thermal Signals at Santiaguito, Guatemala

    Science.gov (United States)

    Branan, Y. K.; Watson, I.; Harris, A. J.; Rose, W.; Bluth, G. J.; Chigna, G.; Mota, M.

    2003-12-01

    With vertical explosions occurring approximately every 40-50 minutes, the Santiaguito dome at Santa Maria Volcano is an ideal system for examining short-term data patterns. A 3-week long field experiment was performed in January 2003 at the Santiaguito Volcano Observatory in order to record high temporal resolution measurements of volcanic activity. We collected digital seismic data from a single vertical component seismometer located approximately 4 km southeast of the active Caliente vent. A portable infrared thermal monitoring unit was deployed daily to record the temperature of the plume as it left the vent at an acquisition rate of 300 measurements per minute. A miniature ultraviolet spectrometer (MUSE) was also deployed daily to measure the SO2 gas emissions just above the vent. This instrument is based on the differential optical absorption spectroscopy (DOAS) technique and allowed for continuous readings at a rate of 36 measurements per minute from approximately 6.5 km south of the Caliente vent. At abstract time, the seismic data is not analyzed, but there is a strong correlation between the SO2 emission and thermal data showing that the expulsed gas heats the dome extensively as it is emitted, with a possibility of different signatures indicating certain types of activity such as pyroclastic flows. It is expected that, with the addition of seismic data and the application of analysis of periodicity using Fourier Transforms, the data will elucidate conduit processes, providing additional vital constraints to sub-surface models.

  7. Anti-inflammatory effects of escin are correlated with the glucocorticoid receptor/NF-κB signaling pathway, but not the COX/PGF2α signaling pathway.

    Science.gov (United States)

    Wang, Hongsheng; Zhang, Leiming; Jiang, Na; Wang, Zhenhua; Chong, Yating; Fu, Fenghua

    2013-08-01

    In China, escin has been widely used in the clinic as a potent anti-inflammatory drug. Previous studies have indicated that escin exerts its anti-inflammatory effect by enhancing the release of glucocorticoids (GCs) and prostaglandin-F2α (PGF2α), and this has been documented in the drug description. However, our previous studies demonstrated that escin did not increase the secretion of GCs, but instead elevated the protein expression of the GC receptor (GR), which may have repressed nuclear factor (NF)-κB-mediated gene expression. The aim of this study was to determine the functions of NF-κB and PGF2α with regard to the anti-inflammatory effect of escin. We investigated the anti-inflammatory effects of dexamethasone, diclofenac and escin against carrageenan-induced paw edema in rats, and observed that escin exerted a GC-like anti-inflammatory effect. In addition, we studied the role of PGF2α in the anti-inflammatory effect exerted by escin in an acetic acid-induced capillary permeability model in mice. The results revealed that the coadministration of escin and diclofenac, a potent prostaglandin-synthesis inhibitor, did not affect the anti-inflammatory effect of escin. Furthermore, we investigated the function of NF-κB with regard to the anti-inflammatory effect exerted by escin in lipopolysaccharide (LPS)-treated mice, and demonstrated that escin significantly inhibited the expression of NF-κB. These results suggest that escin has a GC-like anti-inflammatory effect, and that its mechanisms may be correlated with the GC receptor/NF-κB signaling pathway, but not the COX/PGF2α signaling pathway.

  8. DAQ system for high energy polarimeter at the LHE, JINR: implementation based on the qdpb (data processing with branchpoints) system

    International Nuclear Information System (INIS)

    Isupov, A.Yu.

    2001-01-01

    Online data acquisition (DAQ) system's implementation for the High Energy Polarimeter (HEP) at the LHE, JINR is described. HEP DAQ is based on the qdpb system. Software modules specific for such implementation (HEP data and hardware dependent) are discussed

  9. Activation of parallel fiber feedback by spatially diffuse stimuli reduces signal and noise correlations via independent mechanisms in a cerebellum-like structure.

    Directory of Open Access Journals (Sweden)

    Benjamin Simmonds

    2015-01-01

    Full Text Available Correlations between the activities of neighboring neurons are observed ubiquitously across systems and species and are dynamically regulated by several factors such as the stimulus' spatiotemporal extent as well as by the brain's internal state. Using the electrosensory system of gymnotiform weakly electric fish, we recorded the activities of pyramidal cell pairs within the electrosensory lateral line lobe (ELL under spatially localized and diffuse stimulation. We found that both signal and noise correlations were markedly reduced (>40% under the latter stimulation. Through a network model incorporating key anatomical features of the ELL, we reveal how activation of diffuse parallel fiber feedback from granule cells by spatially diffuse stimulation can explain both the reduction in signal as well as the reduction in noise correlations seen experimentally through independent mechanisms. First, we show that burst-timing dependent plasticity, which leads to a negative image of the stimulus and thereby reduces single neuron responses, decreases signal but not noise correlations. Second, we show trial-to-trial variability in the responses of single granule cells to sensory input reduces noise but not signal correlations. Thus, our model predicts that the same feedback pathway can simultaneously reduce both signal and noise correlations through independent mechanisms. To test this prediction experimentally, we pharmacologically inactivated parallel fiber feedback onto ELL pyramidal cells. In agreement with modeling predictions, we found that inactivation increased both signal and noise correlations but that there was no significant relationship between magnitude of the increase in signal correlations and the magnitude of the increase in noise correlations. The mechanisms reported in this study are expected to be generally applicable to the cerebellum as well as other cerebellum-like structures. We further discuss the implications of such

  10. Retrievals of Cloud Droplet Size from the Research Scanning Polarimeter Data: Validation Using in Situ Measurements

    Science.gov (United States)

    Alexandrov, M. D.; Cairns, B.; Sinclair, K.; Wasilewski, A. P.; Ziemba, L. D.; Crosbie, E.; Hair, J. W.; Hu, Y.; Hostetler, C. A.; Stamnes, S.

    2016-12-01

    We present comparisons of cloud droplet size distributions retrieved from the Research Scanning Polarimeter (RSP) data with correlative in situ measurements made during the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES). This field experiment was based at St. John's airport, Newfoundland, Canada with the latest deployment in May - June 2016. RSP was onboard the NASA C-130 aircraft together with an array of in situ and other remote sensing instrumentation. The RSP is an along-track scanner measuring polarized and total reflectances in 9 spectral channels. Its unique high angular resolution allows for characterization of liquid water droplet size using the rainbow structure observed in the polarized reflectances in the scattering angle range between 135 and 165 degrees. A parametric fitting algorithm applied to the polarized reflectances provides retrievals of the droplet effective radius and variance assuming a prescribed size distribution shape (gamma distribution). In addition to this, we use a non-parametric method, Rainbow Fourier Transform (RFT), which allows us to retrieve the droplet size distribution (DSD) itself. The latter is important in the case of clouds with complex structure, which results in multi-modal DSDs. During NAAMES the aircraft performed a number of flight patterns specifically designed for comparison of remote sensing retrievals and in situ measurements. These patterns consisted of two flight segments above the same straight ground track. One of these segments was flown above clouds allowing for remote sensing measurements, while the other was at the cloud top where cloud droplets were sampled. We compare the DSDs retrieved from the RSP data with in situ measurements made by the Cloud Droplet Probe (CDP). The comparisons show generally good agreement with deviations explainable by the position of the aircraft within cloud and by presence of additional cloud layers in RSP view that do not contribute to the in situ DSDs. In the

  11. Human papillomavirus infection correlates with inflammatory Stat3 signaling activity and IL-17 level in patients with colorectal cancer.

    Directory of Open Access Journals (Sweden)

    Yi Xin Li

    Full Text Available Colorectal cancer (CRC is a major burden of public health and healthcare worldwide. Microbiota has been suggested in promoting chronic inflammation in the intestine which, in turn, promotes tumor development. This study focuses on possible correlations of human papillomavirus (HPV infection with proinflammatory Stat3 signaling activities and the resulting levels of its downstream proinflammatory cytokine IL-17 in CRC patients.HPV was examined using HPV Genotyping Chip technology and constitutively active Stat3 (p-Stat3 and IL-17 levels were tested using immunohistochemistry (IHC in paraffin-embedded cancerous and adjacent normal tissues (ANT from a cohort of 95 CRC patients. Correlation analyses were performed between HPV infection and clinicopathological characteristics, Stat3 activities and IL-17 levels among these CRC patients.Three major findings were observed: (1 HPV infection existed in a high rate of CRC cases (48.4%, 46/95, of which 45 cases (45/46, 97.8% were high-risk HPV16-positive and only one case was HPV53-positive. (2 HPV infection correlated with poorer clinical stages (III+IV of CRC. (3 HPV infection strongly correlated with both constitutively higher Stat3 activities (P<0.01 and higher IL-17 levels (P<0.01 only in CRC tissues but not in ANT tissues.HPV infection is common in CRC patients suggesting potentially preventive effectiveness of HPV vaccination among high-risk young individuals. We have for the first time revealed a tri-lateral relationship among HPV infection, constitutive Stat3 activity and IL-17 level, whose collaborative act may orchestrate a proinflammatory microenvironment in the colorectum that, in turn, may promote carcinogenesis and possibly facilitate progression of CRC.

  12. Correlation of body mass index with Th1/Th2 balance, adhesion molecules and insulin signal transduction in infertile patients

    Directory of Open Access Journals (Sweden)

    Hui-Juan Zhang

    2017-11-01

    Full Text Available Objective: To study the correlation of body mass index with Th1/Th2 balance, adhesion molecules and insulin signal transduction in infertile patients. Methods: A total of 132 patients who received diagnostic curettage due to infertility in Tangshan Maternal and Child Health Hospital between June 2015 and March 2016 were selected as the research subjects and divided into the normal group with BMI 30 kg/m 2 according to BMI, and the levels of Th1/ Th2 cytokines in serum as well as the expression of Th1/Th2 transcription factors, adhesion molecules and insulin signal pathway molecules in endometrial tissue were detected. Results: IFN-γ and TNF-α levels in serum of obesity group and overweight group were significantly higher than those of control group while IL-4, IL-5 and IL-13 levels in serum as well as CD44V6, N-cadherin, FAK, ICAM-1, GLUT-4, IRS-1, PI3K and AKT mRNA expression in endometrial tissue were significantly lower than those of control group; IFN-γ and TNF-α levels in serum of obesity group were significantly higher than those of overweight group while IL-4, IL-5 and IL-13 levels in serum as well as CD44V6, N-cadherin, FAK, ICAM-1, GLUT-4, IRS-1, PI3K and AKT mRNA expression in endometrial tissue were significantly lower than those of overweight group. Conclusion: Weight gain can aggravate the Th1/Th2 disorder, reduce the adhesion molecule expression and hinder the insulin signal transduction in infertile patients.

  13. Development of a hard x-ray polarimeter for gamma-ray bursts

    International Nuclear Information System (INIS)

    McConnell, M. L.; Forrest, D. J.; Macri, J.; Ryan, J. M.; Vestrand, W. T.

    1998-01-01

    We describe recent work on the development of a Compton scatter polarimeter for measuring the polarization of hard X-rays (100-300 keV) from astrophysical sources. Results from measurements with a laboratory prototype are summarized, along with comparisons to Monte Carlo simulations. We also present a new design concept that envisions a complete polarimeter module on the front end of a 5-inch position-sensitive PMT. Although the emphasis of our effort is measuring hard X-ray polarization in solar flares, our design has the advantage that it is sensitive over a rather large FoV (>1 sr), a feature that makes the design especially attractive for γ-ray burst studies

  14. High-precision soft x-ray polarimeter at Diamond Light Source.

    Science.gov (United States)

    Wang, H; Dhesi, S S; Maccherozzi, F; Cavill, S; Shepherd, E; Yuan, F; Deshmukh, R; Scott, S; van der Laan, G; Sawhney, K J S

    2011-12-01

    The development and performance of a high-precision polarimeter for the polarization analysis in the soft x-ray region is presented. This versatile, high-vacuum compatible instrument is supported on a hexapod to simplify the alignment with a resolution less than 5 μrad, and can be moved with its own independent control system easily between different beamlines and synchrotron facilities. The polarimeter can also be used for the characterization of reflection and transmission properties of optical elements. A W/B(4)C multilayer phase retarder was used to characterize the polarization state up to 1200 eV. A fast and accurate alignment procedure was developed, and complete polarization analysis of the APPLE II undulator at 712 eV has been performed.

  15. Non-uniformity calibration for MWIR polarization imagery obtained with integrated microgrid polarimeters

    Science.gov (United States)

    Liu, Hai-Zheng; Shi, Ze-Lin; Feng, Bin; Hui, Bin; Zhao, Yao-Hong

    2016-03-01

    Integrating microgrid polarimeters on focal plane array (FPA) of an infrared detector causes non-uniformity of polarization response. In order to reduce the effect of polarization non-uniformity, this paper constructs an experimental setup for capturing raw flat-field images and proposes a procedure for acquiring non-uniform calibration (NUC) matrix and calibrating raw polarization images. The proposed procedure takes the incident radiation as a polarization vector and offers a calibration matrix for each pixel. Both our matrix calibration and two-point calibration are applied to our mid-wavelength infrared (MWIR) polarization imaging system with integrated microgrid polarimeters. Compared with two point calibration, our matrix calibration reduces non-uniformity by 30 40% under condition of flat-field data test with polarization. The ourdoor scene observation experiment indicates that our calibration can effectively reduce polarization non-uniformity and improve the image quality of our MWIR polarization imaging system.

  16. Design and Deployment of a Multichroic Polarimeter Array on the Atacama Cosmology Telescope

    Science.gov (United States)

    Datta, R.; Austermann, J.; Beall, J. A.; Becker, D.; Coughlin, K. P.; Duff, S. M.; Gallardo, P.A.; Grace, E.; Hasselfield, M.; Henderson, S. W.; hide

    2016-01-01

    We present the design and the preliminary on-sky performance with respect to beams and pass bands of a multichroic polarimeter array covering the 90 and 146 GHz cosmic microwave background bands and its enabling broad-band optical system recently deployed on the Atacama Cosmology Telescope (ACT). The constituent pixels are feedhorn-coupled multichroic polarimeters fabricated at NIST. This array is coupled to the ACT telescope via a set of three silicon lenses incorporating novel broad-band metamaterial anti-reflection coatings. This receiver represents the first multichroic detector array deployed for a CMB experiment and paves the way for the extensive use of multichroic detectors and broad-band optical systems in the next generation of CMB experiments.

  17. A novel comparison of Møller and Compton electron-beam polarimeters

    Directory of Open Access Journals (Sweden)

    J.A. Magee

    2017-03-01

    Full Text Available We have performed a novel comparison between electron-beam polarimeters based on Møller and Compton scattering. A sequence of electron-beam polarization measurements were performed at low beam currents (<5 μA during the Qweak experiment in Hall-C at Jefferson Lab. These low current measurements were bracketed by the regular high current (180 μA operation of the Compton polarimeter. All measurements were found to be consistent within experimental uncertainties of 1% or less, demonstrating that electron polarization does not depend significantly on the beam current. This result lends confidence to the common practice of applying Møller measurements made at low beam currents to physics experiments performed at higher beam currents. The agreement between two polarimetry techniques based on independent physical processes sets an important benchmark for future precision asymmetry measurements that require sub-1% precision in polarimetry.

  18. Statistical Signal Processing by Using the Higher-Order Correlation between Sound and Vibration and Its Application to Fault Detection of Rotational Machine

    OpenAIRE

    Masuike, Hisako; Ikuta, Akira

    2008-01-01

    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...

  19. Optimal configuration of partial Mueller matrix polarimeter for measuring the ellipsometric parameters in the presence of Poisson shot noise and Gaussian noise

    Science.gov (United States)

    Quan, Naicheng; Zhang, Chunmin; Mu, Tingkui

    2018-05-01

    We address the optimal configuration of a partial Mueller matrix polarimeter used to determine the ellipsometric parameters in the presence of additive Gaussian noise and signal-dependent shot noise. The numerical results show that, for the PSG/PSA consisting of a variable retarder and a fixed polarizer, the detection process immune to these two types of noise can be optimally composed by 121.2° retardation with a pair of azimuths ±71.34° and a 144.48° retardation with a pair of azimuths ±31.56° for four Mueller matrix elements measurement. Compared with the existing configurations, the configuration presented in this paper can effectively decrease the measurement variance and thus statistically improve the measurement precision of the ellipsometric parameters.

  20. Global DNA cytosine methylation as an evolving trait: phylogenetic signal and correlated evolution with genome size in Angiosperms

    Directory of Open Access Journals (Sweden)

    Conchita eAlonso

    2015-01-01

    Full Text Available DNA cytosine methylation is a widespread epigenetic mechanism in eukaryotes, and plant genomes commonly are densely methylated. Genomic methylation can be associated with functional consequences such as mutational events, genomic instability or altered gene expression, but little is known on interspecific variation in global cytosine methylation in plants. In this paper, we compare global cytosine methylation estimates obtained by HPLC and use a phylogenetically-informed analytical approach to test for significance of evolutionary signatures of this trait across 54 angiosperm species in 25 families. We evaluate whether interspecific variation in global cytosine methylation is statistically related to phylogenetic distance and also whether it is evolutionarily correlated with genome size (C-value. Global cytosine methylation varied widely between species, ranging between 5.3% (Arabidopsis and 39.2% (Narcissus. Differences between species were related to their evolutionary trajectories, as denoted by the strong phylogenetic signal underlying interspecific variation. Global cytosine methylation and genome size were evolutionarily correlated, as revealed by the significant relationship between the corresponding phylogenetically independent contrasts. On average, a ten-fold increase in genome size entailed an increase of about 10% in global cytosine methylation. Results show that global cytosine methylation is an evolving trait in angiosperms whose evolutionary trajectory is significantly linked to changes in genome size, and suggest that the evolutionary implications of epigenetic mechanisms are likely to vary between plant lineages.

  1. Source levels of echolocation signals vary in correlation with wingbeat cycle in landing big brown bats (Eptesicus fuscus).

    Science.gov (United States)

    Koblitz, Jens C; Stilz, Peter; Schnitzler, Hans-Ulrich

    2010-10-01

    Recordings of the echolocation signals of landing big brown bats with a two-dimensional 16-microphone array revealed that the source level reduction of 7 dB per halving of distance is superimposed by a variation of up to 12 dB within single call groups emitted during the approach. This variation correlates with the wingbeat cycle. The timing of call emission correlates with call group size. First pulses of groups containing many calls are emitted earlier than first calls in groups with fewer calls or single calls. This suggests that the emission of pulse groups follows a fixed motor pattern where the information gained from the preceding pulse group determines how many calls will be emitted in the next group. Single calls and call groups are centred at the middle of the upstroke. Expiration is indicated by call emission. The pause between groups is centred at the middle of the downstroke and indicates inspiration. The hypothesis that the source level variation could be caused by changes in the subglottic pressure due to the contraction of the major flight muscles is discussed.

  2. Radiometric and Polarimetric Accuracy Assessment and Calibration of the Hyper-Angular Rainbow Polarimeter (HARP) Instrument

    Science.gov (United States)

    McBride, B.; Martins, J. V.; Fernandez Borda, R. A.; Barbosa, H. M.

    2017-12-01

    The Laboratory for Aerosols, Clouds, and Optics (LACO) at the University of Maryland, Baltimore County (UMBC) present a novel, wide FOV, hyper-angular imaging polarimeter for the microphysical sampling of clouds and aerosols from aircraft and space. The instrument, the Hyper-Angular Rainbow Polarimeter (HARP), is a precursor to the multi-angle imaging polarimeter solicited by the upcoming NASA Aerosols, Clouds, and Ecosystems (ACE) mission. HARP currently operates in two forms: a spaceborne CubeSat slated for a January 2018 launch to the ISS orbit, and an identical aircraft platform that participated in the Lake Michigan Ozone Study (LMOS) and Aerosol Characterization from Polarimeter and Lidar (ACEPOL) NASA campaigns in 2017. To ensure and validate the instrument's ability to produce high quality Level 2 cloud and aerosol microphysical products, a comprehensive calibration scheme that accounts for flatfielding, radiometry, and all optical interference processes that contribute to the retrieval of Stokes parameters I, Q, and U, is applied across the entirety of HARP's 114° FOV. We present an innovative calibration algorithm that convolves incident polarization from a linear polarization state generator with intensity information observed at three distinct linear polarizations. The retrieved results are pixel-level, modified Mueller matrices that characterize the entire HARP optical assembly, without the need to characterize every individual element or perform ellipsometric studies. Here we show results from several pre- and post- LMOS campaign radiometric calibrations at NASA GSFC and polarimetric calibration using a "polarization dome" that allows for full-FOV characterization of Stokes parameters I, Q, and U. The polarization calibration is verified by passing unpolarized light through partially-polarized, tilted glass plates with well-characterized degree of linear polarization (DoLP). We apply this calibration to a stratocumulous cloud deck case observed

  3. The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz Detector Array of Bolometric Polarimeters

    Science.gov (United States)

    Appel, John W.; Ali, Aamir; Amiri, Mandana; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T.; Colazo, Felipe; hide

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.

  4. The multichannel triple-laser interferometer/polarimeter system at RTP

    NARCIS (Netherlands)

    Rommers, J. H.; Donne, A. J. H.; Karelse, F. A.; Howard, J.

    1997-01-01

    yA 19-channel combined interferometer and polarimeter system has recently become operational at the Rijnhuizen Tokamak Project (a = 0.164 m, R = 0.72 m, B-tor less than or equal to 2.5 T, I-p less than or equal to 150 kA, plasma pulse duration less than or equal to 500 ms), in order to determine the

  5. POLARIMETER: A Soft X-Ray 8-Axis UHV-Diffractometer at BESSY II

    Directory of Open Access Journals (Sweden)

    Andrey Sokolov

    2016-11-01

    Full Text Available A versatile UHV-polarimeter for the EUV XUV spectral range is described which incorporates two optical elements: a phase retarder and a reflection analyzer. Both optics are azimuthally rotatable around the incident synchrotron radiation beam and the incidence angle is freely selectable. This allows for a variety of reflectometry, polarimetry and ellipsometry applications on magnetic or non-magnetic samples and multilayer optical elements.

  6. Instrumentations in x-ray plasma polarization spectroscopy. Crystal spectrometer, polarimeter and detectors for astronomical observations

    Energy Technology Data Exchange (ETDEWEB)

    Baronova, Elena O.; Stepanenko, Mikhail M. [RRC Kurchatov Institute, Nuclear Fusion Institute, Moscow (Russian Federation); Jakubowski, Lech [Soltan Institute for Nuclear Studies, Swierk-Otwock (Poland); Tsunemi, Hiroshi [Osaka Univ., Graduate School of Science, Osaka (Japan)

    2002-08-01

    This report discusses the various problems which are encountered when a crystal spectrometer is used for the purpose of observing polarized x-ray lines. A polarimeter is proposed based on the novel idea of using two series of equivalent atomic planes in a single crystal. The present status of the astronomical x-ray detection techniques are described with emphasis on two dimensional detectors which are polarization sensitive. (author)

  7. POMME: A medium energy deuteron polarimeter based on semi-inclusive d-carbon scattering

    International Nuclear Information System (INIS)

    Bonin, B.; Boudard, A.; Fanet, H.; Fergerson, R.W.; Garcon, M.; Giorgetti, C.; Habault, J.; Le Meur, J.; Lombard, R.M.; Lugol, J.C.; Mayer, B.; Mouly, J.P.; Tomasi-Gustafsson, E.; Morlet, M.; Wiele, J. van de; Willis, A.; Greeniaus, G.; British Columbia Univ., Vancouver; Gaillard, G.; Markowitz, P.; Perdrisat, C.F.; Abegg, R.; Hutcheon, D.A.

    1990-01-01

    POMME is the first calibrated deuteron polarimeter using a d + carbon semi-inclusive scattering reaction. We present the results of its calibration in the region T d =150-700 MeV, with the polarized deuteron beam from the synchrotron Saturne. A parametrization of the measured analyzing powers, and a discussion of the obtained efficiency and figure of merit are also given. (orig.)

  8. Development of a Hydrogen Møller Polarimeter for Precision Parity-Violating Electron Scattering

    Science.gov (United States)

    Gray, Valerie M.

    2013-10-01

    Parity-violating electron scattering experiments allow for testing the Standard Model at low energy accelerators. Future parity-violating electron scattering experiments, like the P2 experiment at the Johannes Gutenberg University, Mainz, Germany, and the MOLLER and SoLID experiments at Jefferson Lab will measure observables predicted by the Standard Model to high precision. In order to make these measurements, we will need to determine the polarization of the electron beam to sub-percent precision. The present way of measuring the polarization, with Møller scattering in iron foils or using Compton laser backscattering, will not easily be able to reach this precision. The novel Hydrogen Møller Polarimeter presents a non-invasive way to measure the electron polarization by scattering the electron beam off of atomic hydrogen gas polarized in a 7 Tesla solenoidal magnetic trap. This apparatus is expected to be operational by 2016 in Mainz. Currently, simulations of the polarimeter are used to develop the detection system at College of William & Mary, while the hydrogen trap and superconducting solenoid magnet are being developed at the Johannes Gutenberg University, Mainz. I will discuss the progress of the design and development of this novel polarimeter system. This material is based upon work supported by the National Science Foundation under Grant No. PHY-1206053.

  9. Silicon photomultipliers as readout elements for a Compton effect polarimeter: the COMPASS project

    CERN Document Server

    Del Monte, E; Brandonisio, A; Muleri, F; Soffitta, P; Costa, E; di Persio, G; Cosimo, S Di; Massaro, E; Morbidini, A; Morelli, E; Pacciani, L; Fabiani, S; Michilli, D; Giarrusso, S; Catalano, O; Impiombato, D; Mineo, T; Sottile, G; Billotta, S

    2016-01-01

    COMpton Polarimeter with Avalanche Silicon readout (COMPASS) is a research and development project that aims to measure the polarization of X-ray photons through Compton Scattering. The measurement is obtained by using a set of small rods of fast scintillation materials with both low-Z (as active scatterer) and high-Z (as absorber), all read-out with Silicon Photomultipliers. By this method we can operate scattering and absorbing elements in coincidence, in order to reduce the background. In the laboratory we are characterising the SiPMs using different types of scintillators and we are optimising the performances in terms of energy resolution, energy threshold and photon tagging efficiency. We aim to study the design of two types of satellite-borne instruments: a focal plane polarimeter to be coupled with multilayer optics for hard X-rays and a large area and wide field of view polarimeter for transients and Gamma Ray Bursts. In this paper we describe the status of the COMPASS project, we report about the la...

  10. First results from the J-TEXT high-resolution three-wave polarimeter-interferometera)

    Science.gov (United States)

    Chen, J.; Zhuang, G.; Wang, Z. J.; Gao, L.; Li, Q.; Chen, W.; Brower, D. L.; Ding, W. X.

    2012-10-01

    A laser-based far-infrared polarimeter-interferometer system utilizing the three-wave technique has been implemented on the J-TEXT tokamak. The polarimeter determines the Faraday effect by measuring the phase difference between two collinear, counter-rotating, circularly polarized laser beams. The first results of the polarimeter-interferometer designed for J-TEXT have been obtained in the most recent J-TEXT experimental campaign. Simultaneous polarimetric and interferometric measurement is achieved, with phase resolution up to 0.1°, at bandwidth of 50 kHz. The temporal resolution, which is dependent on the laser's frequency offset, is ˜1 μs. Continual spatial measurement covering 45 cm (80% of the plasma cross-section) is realized by utilizing 1D parabolic beam expansion optics. Three initial test chords are installed and future plans call for expansion up to 30 chords with 1.5 cm chord spacing, providing high spatial resolution for measurement of electron density and current density profiles. Reliability of both polarimetric and interferometric measurement is confirmed by comparison with computation and data from a hydrocyanic acid (HCN) interferometer. With the high temporal and phase resolution, perturbations associated with the sawtooth cycle and MHD activity have been observed.

  11. Reliability of the two-point measurement of the spatial correlation length from Gaussian-shaped fluctuating signals in fusion-grade plasmas

    Science.gov (United States)

    Kim, Jaewook; Nam, Y. U.; Lampert, M.; Ghim, Y.-C.

    2016-10-01

    A statistical method for the estimation of the spatial correlation lengths of Gaussian-shaped fluctuating signals with two measurement points is examined to quantitatively evaluate its reliability (variance) and accuracy (bias error). The standard deviation of the correlation value is analytically derived for randomly distributed Gaussian shaped fluctuations satisfying stationarity and homogeneity, allowing us to evaluate, as a function of fluctuation-to-noise ratios, the sizes of averaging time windows and the ratios of the distance between the two measurement points to the true correlation length, and the goodness of the two-point measurement for estimating the spatial correlation length. Analytic results are confirmed with numerically generated synthetic data and real experimental data obtained with the KSTAR beam emission spectroscopy diagnostic. Our results can be applied to Gaussian-shaped fluctuating signals where a correlation length must be measured with only two measurement points.

  12. Comparison of Bioradiolocation and Respiratory Plethysmography Signals in Time and Frequency Domains on the Base of Cross-Correlation and Spectral Analysis

    Directory of Open Access Journals (Sweden)

    Maksim Alekhin

    2013-01-01

    Full Text Available Comparison of bioradiolocation and standard respiratory plethysmography signals during simultaneous registration of different types of the human breathing movements is performed in both time and frequency domains. For all couples of synchronized signals corresponding to bioradiolocation and respiratory plethysmography methods, the cross-correlation and spectral functions are calculated, and estimates of their generalized characteristics are defined. The obtained results consider bioradiolocation to be a reliable remote sensing technique for noncontact monitoring of breathing pattern in medical applications.

  13. Using optical fibers with different modes to improve the signal-to-noise ratio of diffuse correlation spectroscopy flow-oximeter measurements

    OpenAIRE

    He, Lian; Lin, Yu; Shang, Yu; Shelton, Brent J.; Yu, Guoqiang

    2013-01-01

    The dual-wavelength diffuse correlation spectroscopy (DCS) flow-oximeter is an emerging technique enabling simultaneous measurements of blood flow and blood oxygenation changes in deep tissues. High signal-to-noise ratio (SNR) is crucial when applying DCS technologies in the study of human tissues where the detected signals are usually very weak. In this study, single-mode, few-mode, and multimode fibers are compared to explore the possibility of improving the SNR of DCS flow-oximeter measure...

  14. Detectability of 21cm-signal during the Epoch of Reionization with 21cm-Lyman-{\\alpha} emitter cross-correlation. II. Foreground contamination

    OpenAIRE

    Yoshiura, S.; Line, J. L. B.; Kubota, K.; Hasegawa, K.; Takahashi, K.

    2017-01-01

    Cross-correlation between the redshifted 21 cm signal and Lyman-{\\alpha} emitters (LAEs) is powerful tool to probe the Epoch of Reionization (EoR). Although the cross-power spectrum (PS) has an advantage of not correlating with foregrounds much brighter than the 21 cm signal, the galactic and extra-galactic foregrounds prevent detection since they contribute to the variance of the cross PS. Therefore, strategies for mitigating foregrounds are required. In this work, we study the impact of for...

  15. Foci of decreased signal on T2-weighted MR images in leiomyosarcomas of soft tissue: correlation between MR and histological findings

    Energy Technology Data Exchange (ETDEWEB)

    Pilavaki, M. E-mail: mayiapil@otenet.gr; Drevelegas, A.; Nenopoulou, H.; Scordalaki, A.; Chourmouzi, D.; Sofroniadis, I.; Dimitriadis, A.S

    2004-09-01

    Objective: Leiomyosarcomas are rare soft tissue sarcomas with varying MR signal characteristics and histologic pictures. The purpose of this study was to investigate the histological features of foci, which showed decreased signal on T2-weighted images in leiomyosarcomas of soft tissue. Material and methods: We reviewed the MR images of six histologically proved cases of leiomyosarcomas of soft tissue and correlated the foci, which showed decreased signal on T2-weighted images with the histologic findings. Result: Microscopic examination revealed that these foci were composed of hyalinization of neoplastic tissue, internal septations, deposition of hemosiderin, or corresponded to metaplastic bone. Conclusion: The authors explain that the foci of decreased signal on T2-weighted MR images correspond to tissue components of the lesion, particularly fibrous tissue, hemosiderin and metaplastic bone. So, the suggestion is that leiomyosarcoma should be considered in the differential diagnosis of soft-tissue tumors that show foci of decreased signal on T2-weighted MR images.

  16. Carotid plaque signal differences among four kinds of T1-weighted magnetic resonance imaging techniques: A histopathological correlation study

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Ayumi; Narumi, Shinsuke; Ohba, Hideki; Yamaguchi, Mao; Terayama, Yasuo [Iwate Medical University, Department of Neurology and Gerontology, Morioka (Japan); Sasaki, Makoto; Kudo, Kohsuke [Iwate Medical University, Institute for Biomedical Sciences, Morioka (Japan); Ogasawara, Kuniaki; Kobayashi, Masakazu [Iwate Medical University, Department of Neurosurgery, Morioka (Japan); Hitomi, Jiro [Iwate Medical University, Department of Anatomy, Morioka (Japan)

    2012-11-15

    Several magnetic resonance (MR) imaging techniques are used to examine atherosclerotic plaque of carotid arteries; however, the best technique for visualizing intraplaque characteristics has yet to be determined. Here, we directly compared four kinds of T1-weighted (T1W) imaging techniques with pathological findings in patients with carotid stenosis. A total of 31 patients who were candidates for carotid endarterectomy were prospectively examined using a 1.5-T MRI scanner, which produced four kinds of T1W images, including non-gated spin echo (SE), cardiac-gated black-blood (BB) fast-SE (FSE), magnetization-prepared rapid acquisition with gradient echo (MPRAGE), and source image of three-dimensional time-of-flight MR angiography (SI-MRA). The signal intensity of the carotid plaque was manually measured, and the contrast ratio (CR) against the adjacent muscle was calculated. CRs from the four imaging techniques were compared to each other and correlated with histopathological specimens. CRs of the carotid plaques mainly containing fibrous tissue, lipid/necrosis, and hemorrhage were significantly different with little overlaps (range: 0.92-1.15, 1.22-1.52, and 1.55-2.30, respectively) on non-gated SE. However, BB-FSE showed remarkable overlaps among the three groups (0.89-1.10, 1.07-1.23, and 1.01-1.42, respectively). MPRAGE could discriminate fibrous plaques from hemorrhagic plaques but not from lipid/necrosis-rich plaques: (0.77-1.07, 1.45-2.43, and 0.85-1.42, respectively). SI-MRA showed the same tendencies (1.01-1.39, 1.45-2.57, and 1.12-1.39, respectively). Among T1W MR imaging techniques, non-gated SE images can more accurately characterize intraplaque components in patients who underwent CEA when compared with cardiac-gated BB-FSE, MPRAGE, and SI-MRA images. (orig.)

  17. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter

    Science.gov (United States)

    Champey, P.; Kobayashi, K.; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, D.; Beabout, B.; Stewart, M.

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1 percent in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1 percent polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30 percent) quantum efficiency at the Lyman-alpha line. The CLASP cameras were designed to operate with 10 e-/pixel/second dark current, 25 e- read noise, a gain of 2.0 +/- 0.5 and 1.0 percent residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  18. Laser Polarimeter for Measurement of Optical Activity of Biological Objects

    Science.gov (United States)

    Protasov, E. A.; Protasov, D. E.; Ryzhkova, A. V.

    In this paper has been described the polarimetric device for measurement of optical activity of biological tissues, where the source of radiation is an infrared laser with a wave λ=0.808 micron. The polarizers used are polarizing prisms of Glan - Taylor. To obtain required angular resolution (0.180/cm) has been developed a device that converts the angle of rotation of the analyzer into electrical signal, which is fed to the appropriate scan digital oscilloscope. The passage of the polarized light through the fingers of the hand was established and the angles of rotation of the polarization vector of the transmitted radiation were measured, the values of which may be determined by the content of hemoglobin in the blood.

  19. Imaging as a tool for the characterization of the gas pixel detector photoelectric polarimeter

    Science.gov (United States)

    Fabiani, Sergio

    2017-08-01

    The Gas Pixel Detector (GPD) is an X-ray polarimeter exploiting the photoelectric effect both to measure polarization and to obtain the image of astrophysical sources. This detector is on board the IXPE (Imaging X-ray Polarimetry Explorer) mission selected by NASA in the framework of the Explorer program. We report on the imaging capability of the GPD as a tool to perform a full detector characterization. The analysis of a radiation beam penetrating inclined in the gas cell is discussed showing how this measurement can be used to study different properties of the gas.

  20. Total elimination of sampling errors in polarization imagery obtained with integrated microgrid polarimeters.

    Science.gov (United States)

    Tyo, J Scott; LaCasse, Charles F; Ratliff, Bradley M

    2009-10-15

    Microgrid polarimeters operate by integrating a focal plane array with an array of micropolarizers. The Stokes parameters are estimated by comparing polarization measurements from pixels in a neighborhood around the point of interest. The main drawback is that the measurements used to estimate the Stokes vector are made at different locations, leading to a false polarization signature owing to instantaneous field-of-view (IFOV) errors. We demonstrate for the first time, to our knowledge, that spatially band limited polarization images can be ideally reconstructed with no IFOV error by using a linear system framework.

  1. Algorithm Validation of the Current Profile Reconstruction of EAST Based on Polarimeter/Interferometer

    International Nuclear Information System (INIS)

    Qian Jinping; Ren Qilong; Wan Baonian; Liu Haiqin; Zeng Long; Luo Zhengping; Chen Dalong; Shi Tonghui; Sun Youwen; Shen Biao; Xiao Bingjia; Lao, L. L.; Hanada, K.

    2015-01-01

    The method of plasma current profile reconstruction using the polarimeter/interferometer (POINT) data from a simulated equilibrium is explored and validated. It is shown that the safety factor (q) profile can be generally reconstructed from the external magnetic and POINT data. The reconstructed q profile is found to reasonably agree with the initial equilibriums. Comparisons of reconstructed q and density profiles using the magnetic data and the POINT data with 3%, 5% and 10% random errors are investigated. The result shows that the POINT data could be used to a reasonably accurate determination of the q profile. (fusion engineering)

  2. CLASP2: The Chromospheric LAyer Spectro-Polarimeter

    Science.gov (United States)

    McKenzie, D. E.; Ishikawa, R.; Bueno, J. Trujillo; Auchere, F.; Rachmeler, L; Kudo, M.; Kobayashi, K.; Winebarger, A.; Bethge, C.; Narukage, N.; hide

    2017-01-01

    A major remaining challenge for heliophysicsis to decipher the magnetic structure of the chromosphere, due to its 'large role in defining how energy is transported into the corona and solar wind' (NASA's Heliophysics Roadmap). Recent observational advances enabled by the Interface Region Imaging Spectrometer (IRIS) have revolutionized our view of the critical role this highly dynamic interface between the photosphere and corona plays in energizing and structuring the outer solar atmosphere. Despite these advances, a major impediment to better understanding the solar atmosphere is our lack of empirical knowledge regarding the direction and strength of the magnetic field in the upper chromosphere. Such measurements are crucial to address several major unresolved issues in solar physics: for example, to constrain the energy flux carried by the Alfven waves propagating through the chromosphere (De Pontieuet al., 2014), and to determine the height at which the plasma ß = 1 transition occurs, which has important consequences for the braiding of magnetic fields (Cirtainet al., 2013; Guerreiroet al., 2014), for propagation and mode conversion of waves (Tian et al., 2014a; Straus et al., 2008) and for non-linear force-free extrapolation methods that are key to determining what drives instabilities such as flares or coronal mass ejections (e.g., De Rosa et al., 2009). The most reliable method used to determine the solar magnetic field vector is the observation and interpretation of polarization signals in spectral lines, associated with the Zeeman and Hanle effects. Magnetically sensitive ultraviolet spectral lines formed in the upper chromosphere and transition region provide a powerful tool with which to probe this key boundary region (e.g., Trujillo Bueno, 2014). Probing the magnetic nature of the chromosphere requires measurement of the Stokes I, Q, U and V profiles of the relevant spectral lines (of which Q, U and V encode the magnetic field information).

  3. Ultrasonic distance and velocity measurement using a pair of LPM signals for cross-correlation method: improvement of Doppler-shift compensation and examination of Doppler velocity estimation.

    Science.gov (United States)

    Hirata, Shinnosuke; Kurosawa, Minoru Kuribayashi

    2012-09-01

    Real-time distance measurement of a moving object with high accuracy and high resolution using an ultrasonic wave is difficult due to the influence of the Doppler effect or the limit of the calculation cost of signal processing. An over-sampling signal processing method using a pair of LPM signals has been proposed for ultrasonic distance and velocity measurement of moving objects with high accuracy and high resolution. The proposed method consists of cross correlation by single-bit signal processing, high-resolution Doppler velocity estimation with wide measurement range and low-calculation-cost Doppler-shift compensation. The over-sampling cross-correlation function is obtained from cross correlation by single-bit signal processing with low calculation cost. The Doppler velocity and distance of the object are determined from the peak interval and peak form in the cross-correlation function by the proposed method of Doppler velocity estimation and Doppler-shift compensation. In this paper, the proposed method of Doppler-shift compensation is improved. Accuracy of the determined distance was improved from approximately within ±140μm in the previous method to approximately within ±10μm in computer simulations. Then, the proposed method of Doppler velocity estimation is evaluated. In computer simulations, accuracy of the determined Doppler velocity and distance were demonstrated within ±8.471mm/s and ±13.87μm. In experiments, Doppler velocities of the motorized stage could be determined within ±27.9mm/s. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Compact acousto-optic imaging spectro-polarimeter for mineralogical investigations in the near infrared.

    Science.gov (United States)

    Belyaev, Denis A; Yushkov, Konstantin B; Anikin, Sergey P; Dobrolenskiy, Yuri S; Laskin, Aleksander; Mantsevich, Sergey N; Molchanov, Vladimir Ya; Potanin, Sergey A; Korablev, Oleg I

    2017-10-16

    Spectral imaging in the near infrared is a promising method for mineralogy analysis, in particular well-suited for airless celestial objects or those with faint atmospheres. Additional information about structure and composition of minerals can be obtained using spectral polarimetry with high spatial resolution. We report design and performance of laboratory prototype for a compact near infrared acousto-optic imaging spectro-polarimeter, which may be implemented for remote or close-up analysis of planetary surfaces. The prototype features telecentric optics, apochromatic design over the bandwidth of 0.8-1.75 µm, and simultaneous imaging of two orthogonal linear polarizations of the same scene with a single FPA detector. When validating the scheme, reflectance spectra of several minerals were measured with the spectral resolution of 100 cm -1 (10 nm passband at 1 µm). When imaging samples, the spatial resolution of 0.6 mm at the target distance of one meter was reached. It corresponds to 100 by 100 diffraction-limited elements resolved at the focal plane array (FPA) for each of the two light polarizations. A similar prototype is also being designed for the spectral range from 1.7 to 3.5 µm. This type of the spectro-polarimeter is considered as a potential reconnaissance and analysis tool for future planetary or moon landers and rovers.

  5. A Wavefront Division Polarimeter for the Measurements of Solute Concentrations in Solutions

    Directory of Open Access Journals (Sweden)

    Sergio Calixto

    2017-12-01

    Full Text Available Polarimeters are useful instruments that measure concentrations of optically active substances in a given solution. The conventional polarimetric principle consists of measuring the rotation angle of linearly polarized light. Here, we present a novel polarimeter based on the study of interference patterns. A Mach–Zehnder interferometer with linearly polarized light at the input is used. One beam passes through the liquid sample and the other is a reference beam. As the linearly polarized sample beam propagates through the optically active solution the vibration plane of the electric field will rotate. As a result, the visibility of the interference pattern at the interferometer output will decrease. Fringe contrast will be maximum when both beams present a polarization perpendicular to the plane of incidence. However, minimum visibility is obtained when, after propagation through the sample the polarization of the sample beam is oriented parallel to the plane of incidence. By using different solute concentrations, a calibration plot is obtained showing the behavior of visibility.

  6. First results of the J-TEXT high-resolution 3-wave polarimeter-interferometer system

    Science.gov (United States)

    Zhuang, G.; Chen, J.; Li, Q.; Gao, L.; Wang, Z. J.; Liu, Y.; Chen, W.

    2013-10-01

    A far-infrared laser polarimeter-interferometer system based on Three-wave technique has been established on the J-TEXT tokamak. The system determines Faraday angle by measuring phase difference between two collinear, counter-rotating, circularly polarized laser beams, and acquires line-integrated electron density simultaneously by phase comparison between the two beams and a third local oscilate (LO) beam. Three seperately pumped HCOOH lasers at 432 μm are adopted as sources, suppling more than 100 mW power output in sum. Parabolic mirrors are used to expand probe beams to 450 mm wide, covering ~ 80% of plasma cross section, which allows profile measurement with high spatial resolution. First experimental results of the polarimeter-interferometer have been obtained. 12 chords (3 cm chord spacing) simultaneous polarimetric and interferometric measurements are achieved, with phase resolution up to 0.1° at bandwidth of 50 kHz. With the high temporal and phase resolution, perturbations associated with the sawtooth cycle and MHD activity have been observed.

  7. A polarimeter for GeV protons of recirculating synchrotron beams

    CERN Document Server

    Bauer, F

    1999-01-01

    A polarimeter for use in recirculating beams of proton synchrotrons with energies from 300 MeV up to several GeV has been developed. The polarimetry is based on the asymmetry measurement of elastic p->p scattering on an internal CH sub 2 fiber target. The forward going protons are detected with two scintillator systems on either side of the beam pipe close to the angle THETA sub f of maximum analyzing power A sub N. Each one operates in coincidence with a broad (DELTA THETA sub b =21.4 deg. ), segmented detector system for the recoil proton of kinematically varying direction THETA sub b; this position resolution is also used for a concurrent measurement of the p->C and nonelastic p->p background. The CH sub 2 fiber can be replaced by a carbon fiber for detailed background studies; 'false' asymmetries are accounted for with a rotation of the polarimeter around the beam axis. Polarimetry has been performed in the internal beam of the Cooler Synchrotron COSY at fixed energies as well as during proton acceleratio...

  8. Performance Verification of the Gravity and Extreme Magnetism Small Explorer GEMS X-Ray Polarimeter

    Science.gov (United States)

    Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kanako, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi; hide

    2014-01-01

    olarimetry is a powerful tool for astrophysical observations that has yet to be exploited in the X-ray band. For satellite-borne and sounding rocket experiments, we have developed a photoelectric gas polarimeter to measure X-ray polarization in the 2-10 keV range utilizing a time projection chamber (TPC) and advanced micro-pattern gas electron multiplier (GEM) techniques. We carried out performance verification of a flight equivalent unit (1/4 model) which was planned to be launched on the NASA Gravity and Extreme Magnetism Small Explorer (GEMS) satellite. The test was performed at Brookhaven National Laboratory, National Synchrotron Light Source (NSLS) facility in April 2013. The polarimeter was irradiated with linearly-polarized monochromatic X-rays between 2.3 and 10.0 keV and scanned with a collimated beam at 5 different detector positions. After a systematic investigation of the detector response, a modulation factor greater than or equal to 35% above 4 keV was obtained with the expected polarization angle. At energies below 4 keV where the photoelectron track becomes short, diffusion in the region between the GEM and readout strips leaves an asymmetric photoelectron image. A correction method retrieves an expected modulation angle, and the expected modulation factor, approximately 20% at 2.7 keV. Folding the measured values of modulation through an instrument model gives sensitivity, parameterized by minimum detectable polarization (MDP), nearly identical to that assumed at the preliminary design review (PDR).

  9. Musical groove is correlated with properties of the audio signal as revealed by computational modelling, depending on musical style

    OpenAIRE

    Madison, Guy; Gouyon, Fabien; Ullén, Fredrik

    2009-01-01

    With groove we mean the subjective experience of wanting to move rhythmically when listening to music. Previous research has indicated that physical properties of the sound signal contribute to groove - as opposed to mere association due to previous exposure, for example. Here, a number of quantitative descriptors of rhythmic and temporal properties were derived from the audio signal by means of computational modelling methods. The music examples were 100 samples from 5 distinct music styles,...

  10. Weak signal acquisition enhancement in software GPS receivers – Pre-filtering combined post-correlation detection approach

    Directory of Open Access Journals (Sweden)

    G. Arul Elango

    2017-01-01

    Full Text Available The Civilian Global Positioning System (GPS receivers often encounter problems of interference and noise which degrade the receiver performance. The conventional methods of parallel code phase search acquisition with coherent, non-coherent and differential coherent detection for weak signal acquisition fail to enhance the signal for all conditions especially, when the Carrier to Noise ratio (C/N0 falls below 15 dB-Hz. Hence, the GPS receiver has to employ sophisticated techniques to excise the noise and to improve the Signal-to-Noise Ratio (SNR of the signal for further processing. In this paper, a pre-filtering technique of reduced rank Singular Spectral Analysis (SSA is proposed for noise excision and is processed through coherent, non-coherent and differential detection postcorrelation methods to retrieve the signal embedded in noise. Monte Carlo simulations carried out to examine the acquisition sensitivity at various power levels with the different postcorrelation approaches indicate that the SSA combined with differential detection approach provides a significant performance improvement with lesser mean acquisition time. It has 96% probability of detection at a worst signal power level of −159 dBm (i.e. C/N0 15 dB-Hz, compared to other conventional methods.

  11. Measurement of the inclusive p-C analyzing power and cross section in the 1 GeV region and calibration of the new polarimeter POMME

    International Nuclear Information System (INIS)

    Bonin, B.; Boudard, A.; Fanet, H.; Fergerson, R.W.; Garcon, M.; Giorgetti, C.; Habault, J.; Le Meur, J.; Lombard, R.M.; Lugol, J.C.; Mayer, B.; Mouly, J.P.; Tomasi-Gustafsson, E.; Morlet, M.; Wiele, J. van de; Willis, A.; Greeniaus, G.; British Columbia Univ., Vancouver; Gaillard, G.; Markowitz, P.; Perdrisat, C.F.; Abegg, R.; Hutcheon, D.A.

    1990-01-01

    We describe the polarimeter POMME, and give the results of its calibration in the region 200-1200 MeV, using the Saturne polarized proton beam. The high energy part of this domain (800-1200 MeV) was previously unexplored. Parametrizations of the inclusive p-C analyzing power and polarimeter efficiency as a function of scattering angle and incident energy are given, completing the data already available at lower energies. The optimization of proton polarimeters in this energy domain is also discussed. (orig.)

  12. Detectability of 21cm-signal during the Epoch of Reionization with 21cm-Lyman-$\\alpha$ emitter cross-correlation. I

    OpenAIRE

    Kubota, Kenji; Yoshiura, Shintaro; Takahashi, Keitaro; Hasegawa, Kenji; Yajima, Hidenobu; Ouchi, Masami; Pindor, B.; Webster, R. L.

    2017-01-01

    Detection of the redshifted 21cm-line signal from neutral hydrogen in the intergalactic medium (IGM) during the Epoch of Reionization (EoR) is complicated by intense foregrounds such as galactic synchrotron and extragalactic radio galaxies. The 21cm-Lyman-$\\alpha$ emitter(LAE) cross-correlation is one of the tools available to reduce the foregrounds because the foreground emission from such radio sources is statistically independent of LAE distribution. LAE surveys during the EoR at redshifts...

  13. Fringe-jump corrected far infrared tangential interferometer/polarimeter for a real-time density feedback control system of NSTX plasmas.

    Science.gov (United States)

    Juhn, J-W; Lee, K C; Hwang, Y S; Domier, C W; Luhmann, N C; Leblanc, B P; Mueller, D; Gates, D A; Kaita, R

    2010-10-01

    The far infrared tangential interferometer/polarimeter (FIReTIP) of the National Spherical Torus Experiment (NSTX) has been set up to provide reliable electron density signals for a real-time density feedback control system. This work consists of two main parts: suppression of the fringe jumps that have been prohibiting the plasma density from use in the direct feedback to actuators and the conceptual design of a density feedback control system including the FIReTIP, control hardware, and software that takes advantage of the NSTX plasma control system (PCS). By investigating numerous shot data after July 2009 when the new electronics were installed, fringe jumps in the FIReTIP are well characterized, and consequently the suppressing algorithms are working properly as shown in comparisons with the Thomson scattering diagnostic. This approach is also applicable to signals taken at a 5 kHz sampling rate, which is a fundamental constraint imposed by the digitizers providing inputs to the PCS. The fringe jump correction algorithm, as well as safety and feedback modules, will be included as submodules either in the gas injection system category or a new category of density in the PCS.

  14. 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.

  15. Analysis of low energy AGS polarimeter data and potential consequences for RHIC spin physics

    International Nuclear Information System (INIS)

    Cadman, R.; Krueger, K.; Spinka, H.; Underwood, D.; Yokosawa, A.; Huang, H.

    2001-01-01

    The small asymmetries measured at G γ = 7.5 during the RHIC spin commissioning were a serious concern. In earlier runs, asymmetries double those from the spin commissioning time (September 2000) had sometimes been observed, and there had been few changes to the AGS polarimeter hardware or operating conditions. Recently, the observed changes in the asymmetries measured at G γ = 7:5 have been ascribed to contamination of the carbon target asymmetry with that from the fishline target and vice-versa, because of the sizeable beam spot size compared to the separation of the targets. This note addresses this hypothesis using the observed asymmetries. This problem could directly impact spin physics at RHIC

  16. Characterization of a high-temperature superconducting bearing for use in a cosmic microwave background polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R [Energy Technology Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Hanany, Shaul [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Matsumura, Tomotake [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Johnson, Bradley [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Jones, Terry [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2005-02-01

    We have previously presented a design for a cosmic microwave background (CMB) polarimeter in which a cryogenically cooled half-wave plate rotates by means of a high-temperature superconducting (HTS) bearing. Here, a prototype bearing, consisting of a commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We measured its coefficient of friction and vibrational property as a function of several parameters, including temperature between 15 and 83 K, rotation frequency between 0.3 and 3.5 Hz, levitation distance between 6 and 10 mm and ambient pressure of {approx}10{sup -7} Torr. We concluded that the low rotational drag of the HTS bearing would allow rotations for long periods with minimal input power and negligible wear and tear, thus making this technology suitable for a future satellite mission.

  17. A Spin-Light Polarimeter for Multi-GeV Longitudinally Polarized Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Mohanmurthy, Prajwal [Mississippi State University, Starkville, MS (United States); Dutta, Dipangkar [Mississippi State University, Starkville, MS (United States) and Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-02-01

    The physics program at the upgraded Jefferson Lab (JLab) and the physics program envisioned for the proposed electron-ion collider (EIC) include large efforts to search for interactions beyond the Standard Model (SM) using parity violation in electroweak interactions. These experiments require precision electron polarimetry with an uncertainty of < 0.5 %. The spin dependent Synchrotron radiation, called "spin-light," can be used to monitor the electron beam polarization. In this article we develop a conceptual design for a "spin-light" polarimeter that can be used at a high intensity, multi-GeV electron accelerator. We have also built a Geant4 based simulation for a prototype device and report some of the results from these simulations.

  18. Design and Tests of the Hard X-Ray Polarimeter X-Calibur

    Science.gov (United States)

    Beilicke, M.; Baring, M. G.; Barthelmy, S.; Binns, W. R.; Buckley, J.; Cowsik, R.; Dowkontt, P.; Garson, A.; Guo, Q.; Haba, Y.; hide

    2012-01-01

    X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOC(mu)S grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10 - 80 keY X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.

  19. Derivation of Cumulus Cloud Dimensions and Shape from the Airborne Measurements by the Research Scanning Polarimeter

    Science.gov (United States)

    Alexandrov, Mikhail D.; Cairns, Brian; Emde, Claudia; Ackerman, Andrew S.; Ottaviani, Matteo; Wasilewski, Andrzej P.

    2016-01-01

    The Research Scanning Polarimeter (RSP) is an airborne instrument, whose measurements have been extensively used for retrievals of microphysical properties of clouds. In this study we show that for cumulus clouds the information content of the RSP data can be extended by adding the macroscopic parameters of the cloud, such as its geometric shape, dimensions, and height above the ground. This extension is possible by virtue of the high angular resolution and high frequency of the RSP measurements, which allow for geometric constraint of the cloud's 2D cross section between a number of tangent lines of view. The retrieval method is tested on realistic 3D radiative transfer simulations and applied to actual RSP data.

  20. A three-cell liquid hydrogen target for an extended focal plane polarimeter

    International Nuclear Information System (INIS)

    Golovanov, L.B.; Chesny, P.; Gheller, J.M.; Guillier, G.; Ladygin, V.P.; Theure, Ph.; Tomasi-Gustafsson, E.

    1996-01-01

    This article describes the design and working principle of a three-cell liquid hydrogen target produced for the high-energy deuteron polarimeter HYPOM. This target uses liquid helium as a cooling agent. After a general description of the apparatus, tests and operating modes are thoroughly explained. In particular the air controlled self-regulation of helium flow in the cryostat to stabilize the liquid hydrogen level is presented. The main feature of this target is the simplicity of the design as well as its safeness towards any incident. Results of cooling down, filling up of the target and stabilization regime were processed during one experiment of physics at synchrotron Saturne II. (orig.)

  1. In-line phase retarder and polarimeter for conversion of linear to circular polarization

    Energy Technology Data Exchange (ETDEWEB)

    Kortright, J.B.; Smith, N.V.; Denlinger, J.D. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    An in-line polarimeter including phase retarder and linear polarizer was designed and commissioned on undulator beamline 7.0 for the purpose of converting linear to circular polarization for experiments downstream. In commissioning studies, Mo/Si multilayers at 95 eV were used both as the upstream, freestanding phase retarder and the downstream linear polarized. The polarization properties of the phase retarder were characterized by direct polarimetry and by collecting MCD spectra in photoemission from Gd and other magnetic surfaces. The resonant birefringence of transmission multilayers results from differing distributions of s- and p-component wave fields in the multilayer when operating near a structural (Bragg) interference condition. The resulting phase retardation is especially strong when the interference is at or near the Brewster angle, which is roughly 45{degrees} in the EUV and soft x-ray ranges.

  2. Design and Tests of the Hard X-ray Polarimeter X-Calibur

    Directory of Open Access Journals (Sweden)

    M. Beilicke

    2014-12-01

    Full Text Available X-ray polarimetry promises to give qualitatively new information bout high-energy astrophysical sources, such as binary black hole  systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested ahard X-ray polarimeter, X-Calibur, to be used in the focal plane of the InFOCuS grazing incidence hard X-ray telescope.X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 20−60 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation; in principal, a similar space-borne experiment could be operated in the 5−100 keV regime. X-Calibur achieves a high detection efficiency of order unity.

  3. Two-dimensional polarimeter with a charge-coupled-device image sensor and a piezoelastic modulator.

    Science.gov (United States)

    Povel, H P; Keller, C U; Yadigaroglu, I A

    1994-07-01

    We present the first measurements and scientific observations of the solar photosphere obtained with a new two-dimensional polarimeter based on piezoelastic modulators and synchronous demodulation in a CCD imager. This instrument, which is developed for precision solar-vector polarimetry, contains a specially masked CCD that has every second row covered with an opaque mask. During exposure the charges are shifted back and forth between covered and light-sensitive rows synchronized with the modulation. In this way Stokes I and one of the other Stokes parameters can be recorded. Since the charge shifting is performed at frequencies well above the seeing frequencies and both polarization states are measured with the same pixel, highly sensitive and accurate polarimetry is achieved. We have tested the instrument in laboratory conditions as well as at three solar telescopes.

  4. Measurement errors induced by deformation of optical axes of achromatic waveplate retarders in RRFP Stokes polarimeters.

    Science.gov (United States)

    Dong, Hui; Tang, Ming; Gong, Yandong

    2012-11-19

    The optical axes of achromatic waveplate retarders (AWR) may deform from ideal linear eigenpolarizations and be frequency-dependent owing to the imperfect design and fabrication. Such deformations result in the ellipticity error and the orientation error of an AWR away from the nominal values. In this paper, we address the measurement errors of Stokes parameters induced by deformation of optical axes of AWRs in roatatable retarder fixed polarizer (RRFP) Stokes polarimeters. A set of theoretical formulas is derived to reveal that such measurement errors actually depend on both retardance and angular orientations of the AWR in use, as well as the state of polarization (SOP) under test. We demonstrate that,by rotating the AWR to N (N≥5) uniformly spaced angles with the angle step of 180°/N or 360°/N, the measurement errors of Stokes parameters induced by the ellipticity error of the AWR can be suppressed compared with the result using any set of four specific angles, especially when the SOP under test is nearly circular. On the other hand, the measurement errors induced by the orientation error of the AWR have more complicated relationships with the angular orientations of the AWR: 1) when the SOP under test is nearly circular, above-mentioned N (N≥5) uniformly spaced angles also lead to much smaller measurement errors than any set of four specific angles; 2) when the SOP under test is nearly linear, N (N≥5) uniformly spaced angles result in smaller or larger measurement errors, depending on the SOP under test, compared with the usually-recommended sets of four specific angles. By theoretical calculations and numerical simulations, we can conclude that the RRFP Stokes polarimeters employing angle sets of N (N≥5) uniformly spaced angles, ( ± 90°, -54°, -18°, 18°, 54°) for instance, can effectively reduce the measurement errors of Stokes parameters induced by the optical axes deformation of the AWR.

  5. Determination of the Kinematics of the Qweak Experiment and Investigation of an Atomic Hydrogen Moller Polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Valerie M. [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2018-01-01

    The Qweak experiment has tested the Standard Model through making a precise measurement of the weak charge of the proton (QpW). This was done through measuring the parity-violating asymmetry for polarized electrons scattering off of unpolarized protons. The parity-violating asymmetry measured is directly proportional to the four-momentum transfer (Q^2) from the electron to the proton. The extraction of QpW from the measured asymmetry requires a precise Q^2 determination. The Qweak experiment had a Q^2 = 24.8 ± 0.1 m(GeV^2) which achieved the goal of an uncertainty of <= 0.5%. From the measured asymmetry and Q^2, QpW was determined to be 0.0719 ± 0.0045, which is in good agreement with the Standard Model prediction. This puts a 7.5 TeV lower limit on possible "new physics". This dissertation describes the analysis of Q^2 for the Qweak experiment. Future parity-violating electron scattering experiments similar to the Qweak experiment will measure asymmetries to high precision in order to test the Standard Model. These measurements will require the beam polarization to be measured to sub-0.5% precision. Presently the electron beam polarization is measured through Moller scattering off of a ferromagnetic foil or through using Compton scattering, both of which can have issues reaching this precision. A novel Atomic Hydrogen Moller Polarimeter has been proposed as a non-invasive way to measure the polarization of an electron beam via Moller scattering off of polarized monatomic hydrogen gas. This dissertation describes the development and initial analysis of a Monte Carlo simulation of an Atomic Hydrogen Moller Polarimeter.

  6. Low signal intensity in motor cortex on susceptibility-weighted MR imaging is correlated with clinical signs of amyotrophic lateral sclerosis: a pilot study.

    Science.gov (United States)

    Endo, Hironobu; Sekiguchi, Kenji; Shimada, Hitoshi; Ueda, Takehiro; Kowa, Hisatomo; Kanda, Fumio; Toda, Tatsushi

    2018-03-01

    There is no reliable objective indicator for upper motor neuron dysfunction in amyotrophic lateral sclerosis (ALS). To determine the clinical significance and potential utility of magnetic resonance (MR) signals, we investigated the relationship between clinical symptoms and susceptibility changes in the motor cortex measured using susceptibility-weighted MR imaging taken by readily available 3-T MRI in clinical practice. Twenty-four ALS patients and 14 control subjects underwent 3-T MR T1-weighted imaging and susceptibility-weighted MR imaging with the principles of echo-shifting with a train of observations (PRESTO) sequence. We analysed relationships between relative susceptibility changes in the motor cortex assessed using voxel-based analysis (VBA) and clinical scores, including upper motor neuron score, ALS functional rating scale revised score, and Medical Research Council sum score on physical examination. Patients with ALS exhibited significantly lower signal intensity in the precentral gyrus on susceptibility-weighted MR imaging compared with controls. Clinical scores were significantly correlated with susceptibility changes. Importantly, the extent of the susceptibility changes in the bilateral precentral gyri was significantly correlated with upper motor neuron scores. The results of our pilot study using VBA indicated that low signal intensity in motor cortex on susceptibility-weighted MR imaging may correspond to clinical symptoms, particularly upper motor neuron dysfunction. Susceptibility-weighted MR imaging may be a useful diagnostic tool as an objective indicator of upper motor neuron dysfunction.

  7. Determination of electron beam polarization using electron detector in Compton polarimeter with less than 1% statistical and systematic uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Amrendra [Mississippi State Univ., Mississippi State, MS (United States)

    2015-05-01

    The Q-weak experiment aims to measure the weak charge of proton with a precision of 4.2%. The proposed precision on weak charge required a 2.5% measurement of the parity violating asymmetry in elastic electron - proton scattering. Polarimetry was the largest experimental contribution to this uncertainty and a new Compton polarimeter was installed in Hall C at Jefferson Lab to make the goal achievable. In this polarimeter the electron beam collides with green laser light in a low gain Fabry-Perot Cavity; the scattered electrons are detected in 4 planes of a novel diamond micro strip detector while the back scattered photons are detected in lead tungstate crystals. This diamond micro-strip detector is the first such device to be used as a tracking detector in a nuclear and particle physics experiment. The diamond detectors are read out using custom built electronic modules that include a preamplifier, a pulse shaping amplifier and a discriminator for each detector micro-strip. We use field programmable gate array based general purpose logic modules for event selection and histogramming. Extensive Monte Carlo simulations and data acquisition simulations were performed to estimate the systematic uncertainties. Additionally, the Moller and Compton polarimeters were cross calibrated at low electron beam currents using a series of interleaved measurements. In this dissertation, we describe all the subsystems of the Compton polarimeter with emphasis on the electron detector. We focus on the FPGA based data acquisition system built by the author and the data analysis methods implemented by the author. The simulations of the data acquisition and the polarimeter that helped rigorously establish the systematic uncertainties of the polarimeter are also elaborated, resulting in the first sub 1% measurement of low energy (?1 GeV) electron beam polarization with a Compton electron detector. We have demonstrated that diamond based micro-strip detectors can be used for tracking in a

  8. A note on errors and signal to noise ratio of binary cross-correlation measurements of system impulse response

    International Nuclear Information System (INIS)

    Cummins, J.D.

    1964-02-01

    The sources of error in the measurement of system impulse response using test signals of a discrete interval binary nature are considered. Methods of correcting for the errors due to theoretical imperfections are given and the variance of the estimate of the system impulse response due to random noise is determined. Several topics related to the main topic are considered e.g. determination of a theoretical model from experimental results. General conclusions about the magnitude of the errors due to the theoretical imperfections are made. (author)

  9. Microembolic signal monitoring and the prediction of thromboembolic events following coil embolization of unruptured intracranial aneurysms: diffusion-weighted imaging correlation.

    Science.gov (United States)

    Cho, Jae-Hoon; Kang, Dong-Hun; Kim, Yong-Won; Park, Jaechan; Kim, Yong-Sun

    2015-02-01

    Microembolic signal (MES) monitoring with transcranial Doppler ultrasonography (TCD) may allow for early prediction of thromboembolisms following endovascular coiling of unruptured intracranial aneurysms (UIAs). However, the method has not gained widespread use and may benefit from correlation with diffusion-weighted imaging (DWI) of acute ischemic lesions after coiling. This purposed to evaluate the relationship between MESs and DWI-positive lesions more precisely. We conducted a prospective study on 45 consecutive patients. TCD was performed over the artery that is dependent on the site of aneurysm, but seven patients (15.6%) could not be examined due to the lack of an adequate cranial window. Consequently, 38 patients were available to detect MESs immediately (MES-1) and 24 h (MES-2) after coiling for UIAs. We also checked DWI 1 day after the coiling and analyzed correlations between the TCD and DWI findings. MES-1 and MES-2 were positive in 25 (65.7%) and 14 (36.8%) patients, respectively. DWI-positive lesions were seen in 20 (52.6%) patients, and only 1 (2.6%) patient was symptomatic. MES-1 and MES-2 were strongly correlated with the number of DWI-positive lesions (Spearman's correlation coefficient = 0.79 and 0.70, P < 0.01 and P < 0.01, respectively). Additionally, there was a significant correlation between MES-1 and MES-2 (Spearman's correlation coefficient = 0.70). Based upon the significant correlation between MES and DWI findings, MES may have a role for early detection of ischemic complications after coiling of UIAs. In addition, future study for further validation with clinical application seems requiring.

  10. (Modic) signal alterations of vertebral endplates and their correlation to a minimally invasive treatment of lumbar disc herniation using epidural injections

    International Nuclear Information System (INIS)

    Liphofer, J.P.; Becker, G.T.; Koester, O.; Theodoridis, T.; Schmid, G.

    2006-01-01

    Purpose: To study the influence of (Modic) signal alterations (SA) of the cartilage endplate (CEP) of vertebrae L3-S1 on the outcome of an in-patient minimally invasive treatment (MIT), using epidural injections on patients with lumbar disc herniation (LDH). Materials and Methods: The MR images of 59 consecutive patients with LDH within segments L3/L4-L5/S1 undergoing in-patient minimally invasive treatment with epidural injections were evaluated in a clinical study. The (Modic) signal alterations of the CEP were recorded using T1- and T2-weighted sagittal images. On the basis of the T2-weighted sagittal images, the extension and distribution of the SA were measured by dividing each CEP into 9 areas. The outcome of the MIT was recorded using the Oswestry Disability Index (ODI) before and after therapy and in a 3-month follow-up. Within a subgroup of patients (n=35), the distribution and extension of the signal alterations were correlated with the development of the ODI. Results: Segments with LDH showed significantly more (p<0.001) SA of the CEP than segments without LDH. Although the extension of the SA was not dependent on sex, it did increase significantly with age (p=0.017). The outcome after MIT did not depend on the sex and age of the patients or on the type od LDH. The SA extension tended to have a negative correlation with the outcome after MIT after 3 months (p=0.071). A significant negative correlation could be established between the SA extension in the central section of the upper endplate and the outcome after 3 months (p=0.019). (orig.)

  11. High resolution polarimeter-interferometer system for fast equilibrium dynamics and MHD instability studies on Joint-TEXT tokamak (invited)a)

    Science.gov (United States)

    Chen, J.; Zhuang, G.; Li, Q.; Liu, Y.; Gao, L.; Zhou, Y. N.; Jian, X.; Xiong, C. Y.; Wang, Z. J.; Brower, D. L.; Ding, W. X.

    2014-11-01

    A high-performance Faraday-effect polarimeter-interferometer system has been developed for the J-TEXT tokamak. This system has time response up to 1 μs, phase resolution perturbations associated with intrinsic Magneto-Hydro-Dynamic (MHD) instabilities and external coil-induced Resonant Magnetic Perturbations (RMP). The 3-wave technique, in which the line-integrated Faraday angle and electron density are measured simultaneously by three laser beams with specific polarizations and frequency offsets, is used. In order to achieve optimum resolution, three frequency-stabilized HCOOH lasers (694 GHz, >35 mW per cavity) and sensitive Planar Schottky Diode mixers are used, providing stable intermediate-frequency signals (0.5-3 MHz) with S/N > 50. The collinear R- and L-wave probe beams, which propagate through the plasma poloidal cross section (a = 0.25-0.27 m) vertically, are expanded using parabolic mirrors to cover the entire plasma column. Sources of systematic errors, e.g., stemming from mechanical vibration, beam non-collinearity, and beam polarization distortion are individually examined and minimized to ensure measurement accuracy. Simultaneous density and Faraday measurements have been successfully achieved for 14 chords. Based on measurements, temporal evolution of safety factor profile, current density profile, and electron density profile are resolved. Core magnetic and density perturbations associated with MHD tearing instabilities are clearly detected. Effects of non-axisymmetric 3D RMP in ohmically heated plasmas are directly observed by polarimetry for the first time.

  12. First attempt of the measurement of the beam polarization at an accelerator with the optical electron polarimeter POLO

    CERN Document Server

    Collin, B; Essabaa, S; Frascaria, R; Gacougnolle, R; Kunne, Ronald Alexander; Aulenbacher, K; Tioukine, V

    2004-01-01

    The conventional methods for measuring the polarization of electron beams are either time consuming, invasive or accurate only to a few percent. We developped a method to measure electron beam polarization by observing the light emitted by argon atoms following their excitation by the impact of polarized electrons. The degree of circular polarization of the emitted fluorescence is directly related to the electron polarization. We tested the polarimeter on a test GaAs source available at the MAMI electron accelerator in Mainz, Germany. The polarimeter determines the polarization of a 50 keV electron beam decelerated to a few eV and interacting with an effusive argon gas jet. The resulting decay of the excited states produces the emission of a circularly polarized radiation line at 811.5 nm which is observed and analyzed.

  13. Double-wedged Wollaston-type polarimeter design and integration to RTT150-TFOSC; initial tests, calibration, and characteristics

    Science.gov (United States)

    Helhel, S.; Khamitov, I.; Kahya, G.; Bayar, C.; Kaynar, S.; Gumerov, R.

    2015-10-01

    Photometric and spectroscopic observation capabilities of 1.5-m Russian-Turkish Telescope RTT150 has been broadened with the integration of presented polarimeter. The well-known double-wedged Wollaston-type dual-beam technique was preferred and applied to design and produce it. The designed polarimeter was integrated into the telescope detector TFOSC, and called TFOSC-WP. Its capabilities and limitations were attempted to be determined by a number of observation sets. Non-polarized and strongly polarized stars were observed to determine its limitations as well as its linearity. An instrumental intrinsic polarization was determined for the 1 × 5 arcmin field of view in equatorial coordinate system, the systematic error of polarization degree as 0.2 %, and position angle as 1.9∘. These limitations and capabilities are denoted as good enough to satisfy telescopes' present and future astrophysical space missions related to GAIA and SRG projects.

  14. A Cross-Correlational Analysis between Electroencephalographic and End-Tidal Carbon Dioxide Signals: Methodological Issues in the Presence of Missing Data and Real Data Results

    Directory of Open Access Journals (Sweden)

    Maria Sole Morelli

    2016-10-01

    Full Text Available Electroencephalographic (EEG irreducible artifacts are common and the removal of corrupted segments from the analysis may be required. The present study aims at exploring the effects of different EEG Missing Data Segment (MDS distributions on cross-correlation analysis, involving EEG and physiological signals. The reliability of cross-correlation analysis both at single subject and at group level as a function of missing data statistics was evaluated using dedicated simulations. Moreover, a Bayesian-based approach for combining the single subject results at group level by considering each subject’s reliability was introduced. Starting from the above considerations, the cross-correlation function between EEG Global Field Power (GFP in delta band and end-tidal CO2 (PETCO2 during rest and voluntary breath-hold was evaluated in six healthy subjects. The analysis of simulated data results at single subject level revealed a worsening of precision and accuracy in the cross-correlation analysis in the presence of MDS. At the group level, a large improvement in the results’ reliability with respect to single subject analysis was observed. The proposed Bayesian approach showed a slight improvement with respect to simple average results. Real data results were discussed in light of the simulated data tests and of the current physiological findings.

  15. Thermal Preference Ranges Correlate with Stable Signals of Universal Stress Markers in Lake Baikal Endemic and Holarctic Amphipods.

    Directory of Open Access Journals (Sweden)

    Denis Axenov-Gribanov

    Full Text Available Temperature is the most pervasive abiotic environmental factor for aquatic organisms. Fluctuations in temperature range lead to changes in metabolic performance. Here, we aimed to identify whether surpassing the thermal preference zones is correlated with shifts in universal cellular stress markers of protein integrity, responses to oxidative stress and lactate content, as indicators of anaerobic metabolism. Exposure of the Lake Baikal endemic amphipod species Eulimnogammarus verrucosus (Gerstfeldt, 1858, Ommatogammarus flavus (Dybowski, 1874 and of the Holarctic amphipod Gammarus lacustris Sars 1863 (Amphipoda, Crustacea to increasing temperatures resulted in elevated heat shock protein 70 (Hsp70 and lactate content, elevated antioxidant enzyme activities (i.e., catalase and peroxidase, and reduced lactate dehydrogenase and glutathione S-transferase activities. Thus, the zone of stability (absence of any significant changes of the studied molecular and biochemical markers correlated with the behaviorally preferred temperatures. We conclude that the thermal behavioral responses of the studied amphipods are directly related to metabolic processes at the cellular level. Thus, the determined thermal ranges may possibly correspond to the thermal optima. This relationship between species-specific behavioral reactions and stress response metabolism may have significant ecological consequences that result in a thermal zone-specific distribution (i.e., depths, feed spectrum, etc. of species. As a consequence, by separating species with different temperature preferences, interspecific competition is reduced, which, in turn, increases a species' Darwinian fitness in its environment.

  16. Design and initial performance of SHARP, a polarimeter for the SHARC-II camera at the Caltech Submillimeter Observatory

    Science.gov (United States)

    Li, H.; Dowell, C. D.; Kirby, L.; Novak, G.; Vaillancourt, J. E.

    2008-01-01

    We have developed a foreoptics module that converts the Submillimeter High Angular Resolution Camera generation II (SHARC-II) camera at the Caltech Submillimeter Observatory into a sensitive imaging polarimeter at wavelengths of 350 and 450 μm. We refer to this module as "SHARP." SHARP splits the incident radiation into two orthogonally polarized beams that are then reimaged onto opposite ends of the 32×12 pixel detector array in SHARC-II. A rotating half-wave plate is used just upstream from the polarization-splitting optics. The effect of SHARP is to convert SHARC-II into a dual-beam 12×12 pixel polarimeter. A novel feature of SHARP's design is the use of a crossed grid in a submillimeter polarimeter. Here we describe the detailed optical design of SHARP and present results of tests carried out during our first few observing runs. At 350 μm, the beam size (9 arc sec), throughput (75%), and instrumental polarization (<1%) are all very close to our design goals.

  17. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chuyu [Peking Univ., Beijing (China)

    2012-12-31

    Beam diagnostics is an essential constituent of any accelerator, so that it is named as "organs of sense" or "eyes of the accelerator." Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the

  18. Gravitational waves and red shifts - A space experiment for testing relativistic gravity using multiple time-correlated radio signals

    Science.gov (United States)

    Smarr, L. L.; Vessot, R. F. C.; Lundquist, C. A.; Decher, R.; Piran, T.

    1983-01-01

    A two-step satellite mission for improving the accuracy of gravitational wave detection and for observing actual gravity waveforms is proposed. The spacecraft would carry both a highly stable hydrogen maser, which would control a transmitter sending signals to earth, and a Doppler transponder operating in the two-way mode. The use of simultaneous one- and two-way Doppler transmissions offers four time records of frequency pulsations, which can reveal gravitational radiation at 1-10 MHz with an amplitude accuracy of a factor of six. The first mission phase would consist of a Shuttle launch into a highly eccentric orbit to obtain measurements of the gravitational redshift using gravitational potentials of different earth regions to establish that gravity is describable by a metric theory. Then, after a boost into a heliocentric orbit at 6 AU, the earth-satellite system could detect gravitational waves in the solar system, as well as bursts emitted by the collisions of supermassive black holes.

  19. Endocannabinod Signal Dysregulation in Autism Spectrum Disorders: A Correlation Link between Inflammatory State and Neuro-Immune Alterations

    Directory of Open Access Journals (Sweden)

    Anna Lisa Brigida

    2017-07-01

    Full Text Available Several studies highlight a key involvement of endocannabinoid (EC system in autism pathophysiology. The EC system is a complex network of lipid signaling pathways comprised of arachidonic acid-derived compounds (anandamide, AEA and 2-arachidonoyl glycerol (2-AG, their G-protein-coupled receptors (cannabinoid receptors CB1 and CB2 and the associated enzymes. In addition to autism, the EC system is also involved in several other psychiatric disorders (i.e., anxiety, major depression, bipolar disorder and schizophrenia. This system is a key regulator of metabolic and cellular pathways involved in autism, such as food intake, energy metabolism and immune system control. Early studies in autism animal models have demonstrated alterations in the brain’s EC system. Autism is also characterized by immune system dysregulation. This alteration includes differential monocyte and macrophage responses, and abnormal cytokine and T cell levels. EC system dysfunction in a monocyte and macrophagic cellular model of autism has been demonstrated by showing that the mRNA and protein for CB2 receptor and EC enzymes were significantly dysregulated, further indicating the involvement of the EC system in autism-associated immunological disruptions. Taken together, these new findings offer a novel perspective in autism research and indicate that the EC system could represent a novel target option for autism pharmacotherapy.

  20. Combined retrievals of boreal forest fire aerosol properties with a polarimeter and lidar

    Directory of Open Access Journals (Sweden)

    K. Knobelspiesse

    2011-07-01

    Full Text Available Absorbing aerosols play an important, but uncertain, role in the global climate. Much of this uncertainty is due to a lack of adequate aerosol measurements. While great strides have been made in observational capability in the previous years and decades, it has become increasingly apparent that this development must continue. Scanning polarimeters have been designed to help resolve this issue by making accurate, multi-spectral, multi-angle polarized observations. This work involves the use of the Research Scanning Polarimeter (RSP. The RSP was designed as the airborne prototype for the Aerosol Polarimetery Sensor (APS, which was due to be launched as part of the (ultimately failed NASA Glory mission. Field observations with the RSP, however, have established that simultaneous retrievals of aerosol absorption and vertical distribution over bright land surfaces are quite uncertain. We test a merger of RSP and High Spectral Resolution Lidar (HSRL data with observations of boreal forest fire smoke, collected during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS. During ARCTAS, the RSP and HSRL instruments were mounted on the same aircraft, and validation data were provided by instruments on an aircraft flying a coordinated flight pattern. We found that the lidar data did indeed improve aerosol retrievals using an optimal estimation method, although not primarily because of the contraints imposed on the aerosol vertical distribution. The more useful piece of information from the HSRL was the total column aerosol optical depth, which was used to select the initial value (optimization starting point of the aerosol number concentration. When ground based sun photometer network climatologies of number concentration were used as an initial value, we found that roughly half of the retrievals had unrealistic sizes and imaginary indices, even though the retrieved spectral optical depths agreed within

  1. Combined Retrievals of Boreal Forest Fire Aerosol Properties with a Polarimeter and Lidar

    Science.gov (United States)

    Knobelspiesse, K.; Cairns, B.; Ottaviani, M.; Ferrare, R.; Haire, J.; Hostetler, C.; Obland, M.; Rogers, R.; Redemann, J.; Shinozuka, Y.; hide

    2011-01-01

    Absorbing aerosols play an important, but uncertain, role in the global climate. Much of this uncertainty is due to a lack of adequate aerosol measurements. While great strides have been made in observational capability in the previous years and decades, it has become increasingly apparent that this development must continue. Scanning polarimeters have been designed to help resolve this issue by making accurate, multi-spectral, multi-angle polarized observations. This work involves the use of the Research Scanning Polarimeter (RSP). The RSP was designed as the airborne prototype for the Aerosol Polarimetery Sensor (APS), which was due to be launched as part of the (ultimately failed) NASA Glory mission. Field observations with the RSP, however, have established that simultaneous retrievals of aerosol absorption and vertical distribution over bright land surfaces are quite uncertain. We test a merger of RSP and High Spectral Resolution Lidar (HSRL) data with observations of boreal forest fire smoke, collected during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS). During ARCTAS, the RSP and HSRL instruments were mounted on the same aircraft, and validation data were provided by instruments on an aircraft flying a coordinated flight pattern. We found that the lidar data did indeed improve aerosol retrievals using an optimal estimation method, although not primarily because of the constraints imposed on the aerosol vertical distribution. The more useful piece of information from the HSRL was the total column aerosol optical depth, which was used to select the initial value (optimization starting point) of the aerosol number concentration. When ground based sun photometer network climatologies of number concentration were used as an initial value, we found that roughly half of the retrievals had unrealistic sizes and imaginary indices, even though the retrieved spectral optical depths agreed within uncertainties to

  2. Concept and realization of the A4 Compton backscattering polarimeter at MAMI

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Han

    2008-12-15

    The main concern of the A4 parity violation experiment at the Mainzer Microtron accelerator facility is to study the electric and magnetic contributions of strange quarks to the charge and magnetism of the nucleons at the low momentum transfer region. More precisely, the A4 collaboration investigates the strange quarks' contribution to the electric and magnetic vector form factors of the nucleons. Thus, it is important that the A4 experiment uses an adequate and precise non-destructive online monitoring tool for the electron beam polarization when measuring single spin asymmetries in elastic scattering of polarized electrons from unpolarized nucleons. As a consequence, the A4 Compton backscattering polarimeter was designed and installed such that we can take the absolute measurement of the electron beam polarization without interruption to the parity violation experiment. The present study shows the development of an electron beam line that is called the chicane for the A4 Compton backscattering polarimeter. The chicane is an electron beam transport line and provides an interaction region where the electron beam and the laser beam overlap. After studying the properties of beam line components carefully, we developed an electron beam control system that makes a beam overlap between the electron beam and the laser beam. Using the system, we can easily achieve the beam overlap in a short time. The electron control system, of which the performance is outstanding, is being used in production beam times. And the study presents the development of a scintillating fiber electron detector that reduces the statistical error in the electron polarization measurement. We totally redesigned the scintillating fiber detector. The data that were taken during a 2008 beam time shows a huge background suppression, approximately 80 percent, while leaving the Compton spectra almost unchanged when a coincidence between the fiber detector and the photon detector is used. Thus, the

  3. Correlation of increased fundus autofluorescence signals at closed macula with visual prognosis after successful macular hole surgery.

    Science.gov (United States)

    Shiragami, Chieko; Shiraga, Fumio; Nitta, Eri; Fukuda, Kouki; Yamaji, Hidetaka

    2012-02-01

    To study the significance of the increased fundus autofluorescence (FAF) signals at closed macula with spectral-domain optical coherence tomography and visual prognosis after successful surgery in eyes with idiopathic full-thickness macular holes (MHs). Seventy-eight eyes of 78 consecutive patients with full-thickness MHs underwent successful standard vitrectomy, with internal limiting membrane peeling and followed by 10% sulfur hexafluoride gas injection. Simultaneous FAF and optical coherence tomography images were recorded at 10 days, and 1, 3, and 6 months postoperatively, using a combined spectral-domain optical coherence tomography-fluorescein angiography device (Spectralis™/HRA Heidelberg Retina Angiograph 2). The appearance of increased FAF in the macula postoperatively and the relationship of FAF and optical coherence tomography findings to best-corrected visual acuity were examined. Stage 2, 3, and 4 MHs were present in 31, 29, and 18 eyes, respectively. The median patient age was 66 years, with a range of 54 to 79 years. In all patients, the MHs were successfully closed, and the preoperative increased FAF corresponding to MH disappeared 10 days after surgery. In 36 eyes (46.2%), however, hyperautofluorescence again appeared in the macular area 1 month postoperatively. This hyperautofluorescence was significantly associated with the recovery of the external limiting membrane lines at the fovea 1 month after surgery (P = 0.001, multiple logistic regression analysis). Also, this recovery of the external limiting membrane lines 1 month postoperatively was significantly associated with the recovery of photoreceptor inner and outer segment junction line 3 months postoperatively at the fovea (P macula 1 month postoperatively, the recovery of the photoreceptor inner and outer segment lines at the fovea 3 months postoperatively, and preoperative good visual acuity (P macula 1 month after successful MH surgery. This hyperautofluorescence could be a sign of good

  4. Classification of THz pulse signals using two-dimensional cross-correlation feature extraction and non-linear classifiers.

    Science.gov (United States)

    Siuly; Yin, Xiaoxia; Hadjiloucas, Sillas; Zhang, Yanchun

    2016-04-01

    This work provides a performance comparison of four different machine learning classifiers: multinomial logistic regression with ridge estimators (MLR) classifier, k-nearest neighbours (KNN), support vector machine (SVM) and naïve Bayes (NB) as applied to terahertz (THz) transient time domain sequences associated with pixelated images of different powder samples. The six substances considered, although have similar optical properties, their complex insertion loss at the THz part of the spectrum is significantly different because of differences in both their frequency dependent THz extinction coefficient as well as differences in their refractive index and scattering properties. As scattering can be unquantifiable in many spectroscopic experiments, classification solely on differences in complex insertion loss can be inconclusive. The problem is addressed using two-dimensional (2-D) cross-correlations between background and sample interferograms, these ensure good noise suppression of the datasets and provide a range of statistical features that are subsequently used as inputs to the above classifiers. A cross-validation procedure is adopted to assess the performance of the classifiers. Firstly the measurements related to samples that had thicknesses of 2mm were classified, then samples at thicknesses of 4mm, and after that 3mm were classified and the success rate and consistency of each classifier was recorded. In addition, mixtures having thicknesses of 2 and 4mm as well as mixtures of 2, 3 and 4mm were presented simultaneously to all classifiers. This approach provided further cross-validation of the classification consistency of each algorithm. The results confirm the superiority in classification accuracy and robustness of the MLR (least accuracy 88.24%) and KNN (least accuracy 90.19%) algorithms which consistently outperformed the SVM (least accuracy 74.51%) and NB (least accuracy 56.86%) classifiers for the same number of feature vectors across all studies

  5. Cross-correlation of motor activity signals from dc-magnetoencephalography, near-infrared spectroscopy, and electromyography.

    Science.gov (United States)

    Sander, Tilmann H; Leistner, Stefanie; Wabnitz, Heidrun; Mackert, Bruno-Marcel; Macdonald, Rainer; Trahms, Lutz

    2010-01-01

    Neuronal and vascular responses due to finger movements were synchronously measured using dc-magnetoencephalography (dcMEG) and time-resolved near-infrared spectroscopy (trNIRS). The finger movements were monitored with electromyography (EMG). Cortical responses related to the finger movement sequence were extracted by independent component analysis from both the dcMEG and the trNIRS data. The temporal relations between EMG rate, dcMEG, and trNIRS responses were assessed pairwise using the cross-correlation function (CCF), which does not require epoch averaging. A positive lag on a scale of seconds was found for the maximum of the CCF between dcMEG and trNIRS. A zero lag is observed for the CCF between dcMEG and EMG. Additionally this CCF exhibits oscillations at the frequency of individual finger movements. These findings show that the dcMEG with a bandwidth up to 8 Hz records both slow and faster neuronal responses, whereas the vascular response is confirmed to change on a scale of seconds.

  6. First Results from BISTRO: A SCUBA-2 Polarimeter Survey of the Gould Belt

    Energy Technology Data Exchange (ETDEWEB)

    Ward-Thompson, Derek; Pattle, Kate; Kirk, Jason M. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Bastien, Pierre; Coudé, Simon [Centre de recherche en astrophysique du Québec and département de physique, Université de Montréal, C.P. 6128, Succ. Centre-ville, Montréal, QC, H3C 3J7 (Canada); Furuya, Ray S. [Tokushima University, Minami Jousanajima-machi 1-1, Tokushima 770-8502 (Japan); Kwon, Woojin; Choi, Minho; Hoang, Thiem [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055 (Korea, Republic of); Lai, Shih-Ping [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Qiu, Keping [School of Astronomy and Space Science, Nanjing University, 163 Xianlin Avenue, Nanjing 210023 (China); Berry, David; Friberg, Per; Graves, Sarah F. [East Asian Observatory, 660 N. A‘ohōkū Place, University Park, Hilo, HI 96720 (United States); Francesco, James Di; Johnstone, Doug [NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Franzmann, Erica [Department of Physics and Astronomy, The University of Manitoba, Winnipeg, Manitoba R3T2N2 (Canada); Greaves, Jane S. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff, CF24 3AA (United Kingdom); Houde, Martin [Department of Physics and Astronomy, The University of Western Ontario, 1151 Richmond Street, London N6A 3K7 (Canada); Koch, Patrick M., E-mail: dward-thompson@uclan.ac.uk, E-mail: kmpattle@uclan.ac.uk, E-mail: jmkirk@uclan.ac.uk, E-mail: spseyres@uclan.ac.uk [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); and others

    2017-06-10

    We present the first results from the B-fields In STar-forming Region Observations (BISTRO) survey, using the Sub-millimetre Common-User Bolometer Array 2 camera, with its associated polarimeter (POL-2), on the James Clerk Maxwell Telescope in Hawaii. We discuss the survey’s aims and objectives. We describe the rationale behind the survey, and the questions that the survey will aim to answer. The most important of these is the role of magnetic fields in the star formation process on the scale of individual filaments and cores in dense regions. We describe the data acquisition and reduction processes for POL-2, demonstrating both repeatability and consistency with previous data. We present a first-look analysis of the first results from the BISTRO survey in the OMC 1 region. We see that the magnetic field lies approximately perpendicular to the famous “integral filament” in the densest regions of that filament. Furthermore, we see an “hourglass” magnetic field morphology extending beyond the densest region of the integral filament into the less-dense surrounding material, and discuss possible causes for this. We also discuss the more complex morphology seen along the Orion Bar region. We examine the morphology of the field along the lower-density northeastern filament. We find consistency with previous theoretical models that predict magnetic fields lying parallel to low-density, non-self-gravitating filaments, and perpendicular to higher-density, self-gravitating filaments.

  7. Performance Characterization of the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) CCD Cameras

    Science.gov (United States)

    Joiner, Reyann; Kobayashi, Ken; Winebarger, Amy; Champey, Patrick

    2014-01-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding rocket instrument currently being developed by NASA's Marshall Space Flight Center (MSFC), the National Astronomical Observatory of Japan (NAOJ), and other partners. The goal of this instrument is to observe and detect the Hanle effect in the scattered Lyman-Alpha UV (121.6nm) light emitted by the Sun's chromosphere. The polarized spectrum imaged by the CCD cameras will capture information about the local magnetic field, allowing for measurements of magnetic strength and structure. In order to make accurate measurements of this effect, the performance characteristics of the three on- board charge-coupled devices (CCDs) must meet certain requirements. These characteristics include: quantum efficiency, gain, dark current, read noise, and linearity. Each of these must meet predetermined requirements in order to achieve satisfactory performance for the mission. The cameras must be able to operate with a gain of 2.0+/- 0.5 e--/DN, a read noise level less than 25e-, a dark current level which is less than 10e-/pixel/s, and a residual non- linearity of less than 1%. Determining these characteristics involves performing a series of tests with each of the cameras in a high vacuum environment. Here we present the methods and results of each of these performance tests for the CLASP flight cameras.

  8. First Results from BISTRO: A SCUBA-2 Polarimeter Survey of the Gould Belt

    Science.gov (United States)

    Ward-Thompson, Derek; Pattle, Kate; Bastien, Pierre; Furuya, Ray S.; Kwon, Woojin; Lai, Shih-Ping; Qiu, Keping; Berry, David; Choi, Minho; Coudé, Simon; Di Francesco, James; Hoang, Thiem; Franzmann, Erica; Friberg, Per; Graves, Sarah F.; Greaves, Jane S.; Houde, Martin; Johnstone, Doug; Kirk, Jason M.; Koch, Patrick M.; Kwon, Jungmi; Lee, Chang Won; Li, Di; Matthews, Brenda C.; Mottram, Joseph C.; Parsons, Harriet; Pon, Andy; Rao, Ramprasad; Rawlings, Mark; Shinnaga, Hiroko; Sadavoy, Sarah; van Loo, Sven; Aso, Yusuke; Byun, Do-Young; Eswaraiah, Chakali; Chen, Huei-Ru; Chen, Mike C.-Y.; Chen, Wen Ping; Ching, Tao-Chung; Cho, Jungyeon; Chrysostomou, Antonio; Chung, Eun Jung; Doi, Yasuo; Drabek-Maunder, Emily; Eyres, Stewart P. S.; Fiege, Jason; Friesen, Rachel K.; Fuller, Gary; Gledhill, Tim; Griffin, Matt J.; Gu, Qilao; Hasegawa, Tetsuo; Hatchell, Jennifer; Hayashi, Saeko S.; Holland, Wayne; Inoue, Tsuyoshi; Inutsuka, Shu-ichiro; Iwasaki, Kazunari; Jeong, Il-Gyo; Kang, Ji-hyun; Kang, Miju; Kang, Sung-ju; Kawabata, Koji S.; Kemper, Francisca; Kim, Gwanjeong; Kim, Jongsoo; Kim, Kee-Tae; Kim, Kyoung Hee; Kim, Mi-Ryang; Kim, Shinyoung; Lacaille, Kevin M.; Lee, Jeong-Eun; Lee, Sang-Sung; Li, Dalei; Li, Hua-bai; Liu, Hong-Li; Liu, Junhao; Liu, Sheng-Yuan; Liu, Tie; Lyo, A.-Ran; Mairs, Steve; Matsumura, Masafumi; Moriarty-Schieven, Gerald H.; Nakamura, Fumitaka; Nakanishi, Hiroyuki; Ohashi, Nagayoshi; Onaka, Takashi; Peretto, Nicolas; Pyo, Tae-Soo; Qian, Lei; Retter, Brendan; Richer, John; Rigby, Andrew; Robitaille, Jean-François; Savini, Giorgio; Scaife, Anna M. M.; Soam, Archana; Tamura, Motohide; Tang, Ya-Wen; Tomisaka, Kohji; Wang, Hongchi; Wang, Jia-Wei; Whitworth, Anthony P.; Yen, Hsi-Wei; Yoo, Hyunju; Yuan, Jinghua; Zhang, Chuan-Peng; Zhang, Guoyin; Zhou, Jianjun; Zhu, Lei; André, Philippe; Dowell, C. Darren; Falle, Sam; Tsukamoto, Yusuke

    2017-06-01

    We present the first results from the B-fields In STar-forming Region Observations (BISTRO) survey, using the Sub-millimetre Common-User Bolometer Array 2 camera, with its associated polarimeter (POL-2), on the James Clerk Maxwell Telescope in Hawaii. We discuss the survey’s aims and objectives. We describe the rationale behind the survey, and the questions that the survey will aim to answer. The most important of these is the role of magnetic fields in the star formation process on the scale of individual filaments and cores in dense regions. We describe the data acquisition and reduction processes for POL-2, demonstrating both repeatability and consistency with previous data. We present a first-look analysis of the first results from the BISTRO survey in the OMC 1 region. We see that the magnetic field lies approximately perpendicular to the famous “integral filament” in the densest regions of that filament. Furthermore, we see an “hourglass” magnetic field morphology extending beyond the densest region of the integral filament into the less-dense surrounding material, and discuss possible causes for this. We also discuss the more complex morphology seen along the Orion Bar region. We examine the morphology of the field along the lower-density northeastern filament. We find consistency with previous theoretical models that predict magnetic fields lying parallel to low-density, non-self-gravitating filaments, and perpendicular to higher-density, self-gravitating filaments.

  9. The First Multichroic Polarimeter Array on the Atacama Cosmology Telescope: Characterization and Performance

    Science.gov (United States)

    Ho, S. P.; Pappas, C. G.; Austermann, J.; Beall, J. A.; Becker, D.; Choi, S. K.; Datta, R.; Duff, S. M.; Gallardo, P. A.; Grace, E.; hide

    2016-01-01

    The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive receiver for the 6-meter Atacama Cosmology Telescope (ACT) and measures the small angular scale polarization anisotropies in the cosmic microwave background (CMB). The full focal plane is composed of three detector arrays, containing over 3000 transition edge sensors (TES detectors) in total. The first two detector arrays, observing at 146 gigahertz, were deployed in 2013 and 2014, respectively. The third and final array is composed of multichroic pixels sensitive to both 90 and 146 gigahertz and saw first light in February 2015. Fabricated at NIST, this dichroic array consists of 255 pixels, with a total of 1020 polarization sensitive bolometers and is coupled to the telescope with a monolithic array of broad-band silicon feedhorns. The detectors are read out using time-division SQUID multiplexing and cooled by a dilution refrigerator at 110 meter Kelvins. We present an overview of the assembly and characterization of this multichroic array in the lab, and the initial detector performance in Chile. The detector array has a TES detector electrical yield of 85 percent, a total array sensitivity of less than 10 microns Kelvin root mean square speed, and detector time constants and saturation powers suitable for ACT CMB observations.

  10. Diffusion-weighted magnetic resonance imaging for the initial characterization of non-fatty soft tissue tumors: correlation between T2 signal intensity and ADC values

    Energy Technology Data Exchange (ETDEWEB)

    Gondim Teixeira, Pedro Augusto [Service d' Imagerie Guilloz, CHU Nancy, Nancy (France); Universite de Lorraine, IADI, UMR S 947, Vandoeuvre-les-Nancy (France); Gay, Frederique; Blum, Alain [Service d' Imagerie Guilloz, CHU Nancy, Nancy (France); Chen, Bailiang; Felblinger, Jacques [Universite de Lorraine, IADI, UMR S 947, Vandoeuvre-les-Nancy (France); Zins, Marie [University Versailles St-Quentin, Versailles (France); Inserm, Centre for research in Epidemiology and Population Health (CESP), U1018, Villejuif (France); Sirveaux, Francois [Centre Chirurgical Emile Galle, Service de Chirurgie Traumatologique et Orthopedique, Nancy (France)

    2016-02-15

    To evaluate the performance of quantitative diffusion-weighted imaging (DWI) correlated with T2 signal in differentiating non-fatty benign from malignant tumors. A total of 76 patients with a histologically confirmed non-fatty soft tissue tumors (46 benign and 30 malignant) were prospectively included in this ethics committee approved study. All patients signed an informed consent and underwent MRI with DWI with two b values (0 and 600). ADC values from the solid components of these tumors were obtained and were correlated with the lesion's signal intensity on T2-weighted fat-saturated sequences. ADC values were obtained from adjacent normal muscle to allow calculation of tumor/muscle ADC ratios. There were 58 hyperintense and 18 iso or hypointense lesions. All hypointense lesions were benign. The mean ADC values for benign and malignant tumors were 1.47 ± 0.54 x 10{sup -3} and 1.17 ± 0.38 x 10{sup -3} mm{sup 2}/s respectively (p < 0.005). The mean ADC ratio in benign iso or hypointense tumors was significantly lower than that of hyperintense ones (0.76 ± 0.21 versus 1.58 ± 0.82 - p < 0.0001). An ADC ratio lower than 0.915 was highly specific for malignancy (96.4 %), whereas an ADC ratio higher than 1.32 was highly sensitive for benign lesions (90 %). ADC analysis can be useful in the initial characterization of T2 hyperintense non-fatty soft tissue masses, although this technique alone is not likely to change patient management. (orig.)

  11. Study of sub-pixel position resolution with time-correlated transient signals in 3D pixelated CdZnTe detectors with varying pixel sizes

    Science.gov (United States)

    Ocampo Giraldo, L.; Bolotnikov, A. E.; Camarda, G. S.; De Geronimo, G.; Fried, J.; Gul, R.; Hodges, D.; Hossain, A.; Ünlü, K.; Vernon, E.; Yang, G.; James, R. B.

    2018-03-01

    We evaluated the sub-pixel position resolution achievable in large-volume CdZnTe pixelated detectors with conventional pixel patterns and for several different pixel sizes: 2.8 mm, 1.72 mm, 1.4 mm and 0.8 mm. Achieving position resolution below the physical dimensions of pixels (sub-pixel resolution) is a practical path for making high-granularity position-sensitive detectors, important for improving the imaging capability of CZT gamma cameras. It also allows for making more accurate corrections of response non-uniformities caused by crystal defects, thus enabling use of standard-grade (unselected) and less expensive CZT crystals for producing large-volume position-sensitive CZT detectors feasible for many practical applications. We analyzed the digitized charge signals from a representative 9 pixels and the cathode, generated using a pulsed-laser light beam focused down to 10 μm (650 nm) to scan over a selected 3 × 3 pixel area. We applied our digital pulse processing technique to the time-correlated signals captured from adjacent pixels to achieve and evaluate the capability for sub-pixel position resolution. As an example, we also demonstrated an application of 3D corrections to improve the energy resolution and positional information of the events for the tested detectors.

  12. Using optical fibers with different modes to improve the signal-to-noise ratio of diffuse correlation spectroscopy flow-oximeter measurements

    Science.gov (United States)

    He, Lian; Lin, Yu; Shang, Yu; Shelton, Brent J.; Yu, Guoqiang

    2013-03-01

    The dual-wavelength diffuse correlation spectroscopy (DCS) flow-oximeter is an emerging technique enabling simultaneous measurements of blood flow and blood oxygenation changes in deep tissues. High signal-to-noise ratio (SNR) is crucial when applying DCS technologies in the study of human tissues where the detected signals are usually very weak. In this study, single-mode, few-mode, and multimode fibers are compared to explore the possibility of improving the SNR of DCS flow-oximeter measurements. Experiments on liquid phantom solutions and in vivo muscle tissues show only slight improvements in flow measurements when using the few-mode fiber compared with using the single-mode fiber. However, light intensities detected by the few-mode and multimode fibers are increased, leading to significant SNR improvements in detections of phantom optical property and tissue blood oxygenation. The outcomes from this study provide useful guidance for the selection of optical fibers to improve DCS flow-oximeter measurements.

  13. Regulation of angiogenesis by vascular endothelial growth factor and angiopoietin-1 in the rat aorta model: distinct temporal patterns of intracellular signaling correlate with induction of angiogenic sprouting.

    Science.gov (United States)

    Zhu, Wen-Hui; MacIntyre, Angela; Nicosia, Roberto Francesco

    2002-09-01

    Vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) promote the spontaneous angiogenic response of freshly cut rat aortic rings. When VEGF and Ang-1 were tested in cultures of 14-day-old rings, which are quiescent and unable to spontaneously produce neovessels, only VEGF was capable of inducing an angiogenic response. Ang-1 failed to initiate angiogenesis in this system, but significantly potentiated VEGF-induced neovessel sprouting. Potential differences in cell signaling triggered by VEGF and Ang-1 were evaluated in cultures of quiescent rings. VEGF induced biphasic and prolonged (15 minutes and 4 to 24 hours) phosphorylation of p44/42 MAPK and Akt, while the effect of Ang-1 was transient and monophasic (15 minutes). Both VEGF and Ang-1 induced rapid, monophasic (15 minutes) phosphorylation of p38 MAPK. When VEGF and Ang-1 were administered together, the second peak of VEGF-induced p44/42 MAPK phosphorylation was markedly reduced. The effect of the VEGF/Ang-1 combination on AKT phosphorylation was, instead, additive over time, and sustained over a 24-hour period. The VEGF/Ang-1 combination caused an additive effect also on p38 MAPK phosphorylation at 1 hour. Confocal microscopy of VEGF-, Ang-1, or VEGF/Ang-1-stimulated aortic rings double stained at time points of maximal phosphorylation for cell markers and signal transduction proteins demonstrated phosphorylated p44/42 MAPK, p38 MAPK, and Akt predominantly in endothelial cells. Experiments with specific inhibitors demonstrated that p44/42 MAPK and Akt, but not p38 MAPK, are necessary for neovessel sprouting. These results identify p44/42 MAPK and Akt as critical intracellular mediators of angiogenesis, whose transient phosphorylation is, however, not sufficient for the initiation of this process. The observation that sustained phosphorylation of these signaling pathways, particularly of Akt, correlates with induction of angiogenesis suggests that the duration of phosphorylation signals

  14. MEASUREMENT OF LOW ENERGY DETECTION EFFICIENCY OF A PLASTIC SCINTILLATOR: IMPLICATIONS ON THE LOWER ENERGY LIMIT AND SENSITIVITY OF A HARD X-RAY FOCAL PLANE COMPTON POLARIMETER

    International Nuclear Information System (INIS)

    Chattopadhyay, T.; Vadawale, S. V.; Shanmugam, M.; Goyal, S. K.

    2014-01-01

    The polarization measurements in X-rays offer a unique opportunity for the study of physical processes under the extreme conditions prevalent at compact X-ray sources, including gravitation, magnetic field, and temperature. Unfortunately, there has been no real progress in observational X-ray polarimetry thus far. Although photoelectron tracking-based X-ray polarimeters provide realistic prospects of polarimetric observations, they are effective in the soft X-rays only. With the advent of hard X-ray optics, it has become possible to design sensitive X-ray polarimeters in hard X-rays based on Compton scattering. An important point that should be carefully considered for the Compton polarimeters is the lower energy threshold of the active scatterer, which typically consists of a plastic scintillator due to its lowest effective atomic number. Therefore, an accurate understanding of the plastic scintillators energy threshold is essential to make a realistic estimate of the energy range and sensitivity of any Compton polarimeter. In this context, we set up an experiment to investigate the plastic scintillators behavior for very low energy deposition events. The experiment involves the detection of Compton scattered photons from a long, thin, plastic scintillator (a similar configuration as the eventual Compton polarimeter) by a high resolution CdTe detector at different scattering angles. We find that it is possible to detect energy deposition well below 1 keV, though with decreasing efficiency. We present detailed semianalytical modeling of our experimental setup and discuss the results in the context of the energy range and sensitivity of the Compton polarimeter involving plastic scintillators

  15. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    Science.gov (United States)

    Champey, Patrick; Kobayashi, Ken; Winebarger, Amy; Cirtin, Jonathan; Hyde, David; Robertson, Bryan; Beabout, Brent; Beabout, Dyana; Stewart, Mike

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1% in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1% polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30%) quantum efficiency at the Lyman-$\\alpha$ line. The CLASP cameras were designed to operate with =10 e- /pixel/second dark current, = 25 e- read noise, a gain of 2.0 and =0.1% residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  16. Development and manufacturing of panoramic Stokes polarimeter using the polarization films in the Main Astronomical Observatory of NAS of Ukraine

    Science.gov (United States)

    Vidmachenko, A. P.; Ivanov, Yu. S.; Syniavskyi, I. I.; Sergeev, A. V.

    2015-08-01

    In the Main Astronomical Observatory of NAS of Ukraine is proposed and implemented the concept of the imaging Stokes polarimeter [1-5]. This device allows carrying out measurements of the four Stokes vector components at the same time, in a wide field, and without any restrictions on the relative aperture of the optical system. Its scheme is developed so that only by turning wheel with replaceable elements, photopolarimeter could be transformed into a low resolution spectropolarimeter. The device has four film's polarizers with positional angles 0°, 45°, 90°, 135°. The device uses a system of special deflecting prisms in each channel. These prisms were achromatizing in the spectral range of 420-850 nm [2], the distortion of the polarimeter optical system is less than 0.65%. In manufacturing version of spectropolarimeter provided for the possibility of using working on passing the diffraction grating with a frequency up to 100 lines/mm. Has begun the laboratory testing of instrument. References. 1. Sinyavskii I.I., Ivanov Yu. S., Vidmachenko Anatoliy P., Karpov N.V. Panoramic Stokes-polarimeter // Ecological bulettin of research centers of the Black Sea Economic Cooperation. - 2013. - V. 3, No 4. - P. 123-127. 2. Sinyavskii I. I., Ivanov Yu. S., Vil'machenko A. P. Concept of the construction, of the optical setup of a panoramic Stokes polarimeter for small telescopes // Journal of Optical Technology. - 2013. - V. 80, Issue 9. - P. 545-548. 3. Vidmachenko A. P., Ivanov Yu. S., Morozhenko A. V., Nevodovsky E. P., Syniavskyi I. I., Sosonkin M. G. Spectropolarimeter of ground-based accompanying for the space experiment "Planetary Monitoring" // Kosmichna Nauka i Tekhnologiya. - 2007. - V. 13, No. 1, p. 63 - 70. 4. Yatskiv Ya. S., Vidmachenko A. P., Morozhenko A. V., Sosonkin M. G., Ivanov Yu. S., Syniavskyi I. I. Spectropolarimetric device for overatmospheric investigations of Solar System bodies // Kosmichna Nauka i Tekhnologiya. - 2008. - V. 14, No. 2. - P. 56

  17. Preliminary Neutronics Analysis of the ITER Toroidal Interferometer and Polarimeter Diagnostic Corner Cube Retroreflectors

    Energy Technology Data Exchange (ETDEWEB)

    Tresemer, K. R.

    2015-07-01

    ITER is an international project under construction in France that will demonstrate nuclear fusion at a power plant-relevant scale. The Toroidal Interferometer and Polarimeter (TIP) Diagnostic will be used to measure the plasma electron line density along 5 laser-beam chords. This line-averaged density measurement will be input to the ITER feedback-control system. The TIP is considered the primary diagnostic for these measurements, which are needed for basic ITER machine control. Therefore, system reliability & accuracy is a critical element in TIP’s design. There are two major challenges to the reliability of the TIP system. First is the survivability and performance of in-vessel optics and second is maintaining optical alignment over long optical paths and large vessel movements. Both of these issues greatly depend on minimizing the overall distortion due to neutron & gamma heating of the Corner Cube Retroreflectors (CCRs). These are small optical mirrors embedded in five first wall locations around the vacuum vessel, corresponding to certain plasma tangency radii. During the development of the design and location of these CCRs, several iterations of neutronics analyses were performed to determine and minimize the total distortion due to nuclear heating of the CCRs. The CCR corresponding to TIP Channel 2 was chosen for analysis as a good middle-road case, being an average distance from the plasma (of the five channels) and having moderate neutron shielding from its blanket shield housing. Results show that Channel 2 meets the requirements of the TIP Diagnostic, but barely. These results suggest other CCRs might be at risk of exceeding thermal deformation due to nuclear heating.

  18. Performance measurement of HARPO: A time projection chamber as a gamma-ray telescope and polarimeter

    Science.gov (United States)

    Gros, P.; Amano, S.; Attié, D.; Baron, P.; Baudin, D.; Bernard, D.; Bruel, P.; Calvet, D.; Colas, P.; Daté, S.; Delbart, A.; Frotin, M.; Geerebaert, Y.; Giebels, B.; Götz, D.; Hashimoto, S.; Horan, D.; Kotaka, T.; Louzir, M.; Magniette, F.; Minamiyama, Y.; Miyamoto, S.; Ohkuma, H.; Poilleux, P.; Semeniouk, I.; Sizun, P.; Takemoto, A.; Yamaguchi, M.; Yonamine, R.; Wang, S.

    2018-01-01

    We analyse the performance of a gas time projection chamber (TPC) as a high-performance gamma-ray telescope and polarimeter in the e+e- pair-creation regime. We use data collected at a gamma-ray beam of known polarisation. The TPC provides two orthogonal projections (x, z) and (y, z) of the tracks induced by each conversion in the gas volume. We use a simple vertex finder in which vertices and pseudo-tracks exiting from them are identified. We study the various contributions to the single-photon angular resolution using Monte Carlo simulations, compare them with the experimental data and find that they are in excellent agreement. The distribution of the azimuthal angle of pair conversions shows a bias due to the non-cylindrical-symmetric structure of the detector. This bias would average out for a long duration exposure on a space mission, but for this pencil-beam characterisation we have ensured its accurate simulation by a double systematics-control scheme, data taking with the detector rotated at several angles with respect to the beam polarisation direction and systematics control with a non-polarised beam. We measure, for the first time, the polarisation asymmetry of a linearly polarised gamma-ray beam in the low energy pair-creation regime. This sub-GeV energy range is critical for cosmic sources as their spectra are power laws which fall quickly as a function of increasing energy. This work could pave the way to extending polarised gamma-ray astronomy beyond the MeV energy regime.

  19. THE IMAGING PROPERTIES OF THE GAS PIXEL DETECTOR AS A FOCAL PLANE POLARIMETER

    International Nuclear Information System (INIS)

    Fabiani, S.; Costa, E.; Del Monte, E.; Muleri, F.; Soffitta, P.; Rubini, A.; Bellazzini, R.; Brez, A.; De Ruvo, L.; Minuti, M.; Pinchera, M.; Sgró, C.; Spandre, G.; Spiga, D.; Tagliaferri, G.; Pareschi, G.; Basso, S.; Citterio, O.; Burwitz, V.; Burkert, W.

    2014-01-01

    X-rays are particularly suited to probing the physics of extreme objects. However, despite the enormous improvements of X-ray astronomy in imaging, spectroscopy, and timing, polarimetry remains largely unexplored. We propose the photoelectric polarimeter Gas Pixel Detector (GPD) as a candidate instrument to fill the gap created by more than 30 yr without measurements. The GPD, in the focus of a telescope, will increase the sensitivity of orders of magnitude. Moreover, since it can measure the energy, the position, the arrival time, and the polarization angle of every single photon, it allows us to perform polarimetry of subsets of data singled out from the spectrum, the light curve, or an image of the source. The GPD has an intrinsic, very fine imaging capability, and in this work we report on the calibration campaign carried out in 2012 at the PANTER X-ray testing facility of the Max-Planck-Institut für extraterrestrische Physik of Garching (Germany) in which, for the first time, we coupled it with a JET-X optics module with a focal length of 3.5 m and an angular resolution of 18 arcsec at 4.5 keV. This configuration was proposed in 2012 aboard the X-ray Imaging Polarimetry Explorer (XIPE) in response to the ESA call for a small mission. We derived the imaging and polarimetric performance for extended sources like pulsar wind nebulae and supernova remnants as case studies for the XIPE configuration and also discuss possible improvements by coupling the detector with advanced optics that have a finer angular resolution and larger effective areas to study extended objects with more detail

  20. DAQ systems for the high energy and nuclotron internal target polarimeters with network access to polarization calculation results and raw data

    International Nuclear Information System (INIS)

    Isupov, A.Yu.

    2004-01-01

    On-line data acquisition (DAQ) system for the Nuclotron Internal Target Polarimeter (ITP) at the LHE, JINR, is explained in respect of design and implementation, based on the distributed data acquisition and processing system qdpb. Software modules specific for this implementation (dependent on ITP data contents and hardware layout) are discussed briefly in comparison with those for the High Energy Polarimeter (HEP) at the LHE, JINR. User access methods both to raw data and to results of polarization calculations of the ITP and HEP are discussed

  1. Calibration and performance studies of the balloon-borne hard X-ray polarimeter PoGO+

    Science.gov (United States)

    Chauvin, M.; Friis, M.; Jackson, M.; Kawano, T.; Kiss, M.; Mikhalev, V.; Ohashi, N.; Stana, T.; Takahashi, H.; Pearce, M.

    2017-07-01

    Polarimetric observations of celestial sources in the hard X-ray band stand to provide new information on emission mechanisms and source geometries. PoGO+ is a Compton scattering polarimeter (20-150 keV) optimised for the observation of the Crab (pulsar and wind nebula) and Cygnus X-1 (black hole binary), from a stratospheric balloon-borne platform launched from the Esrange Space Centre in summer 2016. Prior to flight, the response of the polarimeter has been studied with polarised and unpolarised X-rays allowing a Geant4-based simulation model to be validated. The expected modulation factor for Crab observations is found to be MCrab = (41.75 ± 0.85) % , resulting in an expected Minimum Detectable Polarisation (MDP) of 7.3% for a 7 day flight. This will allow a measurement of the Crab polarisation parameters with at least 5 σ statistical significance assuming a polarisation fraction ∼ 20 % - a significant improvement over the PoGOLite Pathfinder mission which flew in 2013 and from which the PoGO+ design is developed.

  2. Measurement errors resulted from misalignment errors of the retarder in a rotating-retarder complete Stokes polarimeter.

    Science.gov (United States)

    Dai, Hu; Yan, Changxiang

    2014-05-19

    Rotatable retarder fixed polarizer (RRFP) Stokes polarimeters, which employ uniformly spaced angles over 180° or 360°, are most commonly used to detect the state of polarization (SOP) of an electromagnetic (EM) wave. The misalignment error of the retarder is one of the major error sources. We suppose that the misalignment errors of the retarder obey a uniform normal distribution and are independent of each other. Then, we derive analytically the covariance matrices of the measurement errors. Based on the covariance matrices derived, we can conclude that 1) the measurement errors are independent of the incident intensity s0, but seriously depend on the Stokes parameters (s1, s2, s3) and the retardance of the retarder δ; 2) for any mean incident SOP, the optimal initial angle and retardance to minimize the measurement error both can be achieved; 3) when N = 5, 10, 12, the initial orienting angle could be used as an added degree of freedom to strengthen the immunity of RRFP Stokes polarimeters to the misalignment error. Finally, a series of simulations are performed to verify these theoretical results.

  3. Using a polarizing film in the manufacture of panoramic Stokes polarimeters at the Main Astronomical Observatory of the National Academy of Sciences of Ukraine

    Science.gov (United States)

    Sinyavskiy, I. I.; Ivanov, Yu. S.; Vidmachenko, A. P.; Sergeev, A. V.

    2013-09-01

    MAO of NASU proposed and implemented the concept [1] of imaging Stokes polarimeter, which allows to measure four components of the Stokes vector at the same time, in a wide field, and without restrictions on the relative aperture of the system. And polarimeter can be converted into low-resolution spectropolarimeter by rotation of the wheel with replaceable elements. To full utilization of the CCD area in the device installed four film's polarizer with positional angles 0°, 45°, 90°, 135°. In each channel of this device installed the system of special deflecting prisms, which achromatize for the spectral range 420-850 nm [2]. Distortion is less than 0.65%. Also have the opportunity the use of the diffraction grating with a frequency up to 100 lines / mm, working on the transmission. References. 1. Sinyavskii I.I., Ivanov Yu.S., Vidmachenko A.P., Karpov N.V. Panoramic Stokes polarimeter // Ecological Bulletin of Research Centers of the Black Sea Economic Cooperation, ISSN: 1729-5459. - 2013 - V. 3, No 4. - P. 123-127. 2. Sinyavskii, I. I.; Ivanov, Yu. S.; Vil'machenko, A. P. Concept of the construction, of the optical setup of a panoramic Stokes polarimeter for small telescopes // Journal of Optical Technology. - 2013. - V. 80, Issue 9. - P. 545-548.

  4. PEPSI: The high-resolution échelle spectrograph and polarimeter for the Large Binocular Telescope

    Science.gov (United States)

    Strassmeier, K. G.; Ilyin, I.; Järvinen, A.; Weber, M.; Woche, M.; Barnes, S. I.; Bauer, S.-M.; Beckert, E.; Bittner, W.; Bredthauer, R.; Carroll, T. A.; Denker, C.; Dionies, F.; DiVarano, I.; Döscher, D.; Fechner, T.; Feuerstein, D.; Granzer, T.; Hahn, T.; Harnisch, G.; Hofmann, A.; Lesser, M.; Paschke, J.; Pankratow, S.; Plank, V.; Plüschke, D.; Popow, E.; Sablowski, D.

    2015-05-01

    PEPSI is the bench-mounted, two-arm, fibre-fed and stabilized Potsdam Echelle Polarimetric and Spectroscopic Instrument for the 2×8.4 m Large Binocular Telescope (LBT). Three spectral resolutions of either 43 000, 120 000 or 270 000 can cover the entire optical/red wavelength range from 383 to 907 nm in three exposures. Two 10.3k×10.3k CCDs with 9-μm pixels and peak quantum efficiencies of 94-96 % record a total of 92 échelle orders. We introduce a new variant of a wave-guide image slicer with 3, 5, and 7 slices and peak efficiencies between 92-96 %. A total of six cross dispersers cover the six wavelength settings of the spectrograph, two of them always simultaneously. These are made of a VPH-grating sandwiched by two prisms. The peak efficiency of the system, including the telescope, is 15 % at 650 nm, and still 11 % and 10 % at 390 nm and 900 nm, respectively. In combination with the 110 m2 light-collecting capability of the LBT, we expect a limiting magnitude of ≈ 20th mag in V in the low-resolution mode. The R = 120 000 mode can also be used with two, dual-beam Stokes IQUV polarimeters. The 270 000-mode is made possible with the 7-slice image slicer and a 100-μm fibre through a projected sky aperture of 0.74 arcsec, comparable to the median seeing of the LBT site. The 43 000-mode with 12-pixel sampling per resolution element is our bad seeing or faint-object mode. Any of the three resolution modes can either be used with sky fibers for simultaneous sky exposures or with light from a stabilized Fabry-Pérot étalon for ultra-precise radial velocities. CCD-image processing is performed with the dedicated data-reduction and analysis package PEPSI-S4S. Its full error propagation through all image-processing steps allows an adaptive selection of parameters by using statistical inferences and robust estimators. A solar feed makes use of PEPSI during day time and a 500-m feed from the 1.8 m VATT can be used when the LBT is busy otherwise. In this paper, we

  5. Radiation, smoke and clouds observed in the southeastern Atlantic with the Research Scanning Polarimeter

    Science.gov (United States)

    Sinclair, K.; Cairns, B.; Stamnes, S.; Chowdhary, J.; Ferrare, R. A.; Hostetler, C. A.; Burton, S. P.

    2017-12-01

    The ObseRvations of Aerosols above Clouds and their interactions (ORACLES) project is making a series of field deployments to the southeastern Atlantic with NASA ER-2 and P3 aircraft to acquire both detailed remote sensing observations and in situ measurements of the aerosols and clouds in that region. This area is home to one of the largest low-level cloud decks on Earth that is seasonally affected by vast plumes of smoke from biomass burning, which in effect provides a natural experiment testing the radiative and microphysical interactions between the smoke and the clouds. The downward solar radiation at the surface, or cloud top, is always reduced by the presence of smoke. However, whether the amount of sunlight reflected back out to space is increased, or decreased by the presence of smoke is sensitively dependent on the brightness of the clouds and the fraction of light that the smoke absorbs each time light hits a smoke particle. In this study we use data from the Research Scanning Polarimeter, an along track scanning instrument, that provides measurements of the Stokes parameters I, Q and U at 410, 470, 555, 670, 865, 960, 1590, 1880 and 2260 nm at 150 viewing angles over a range of ±60° from nadir for each contiguous sub-aircraft pixel ( 300 m in size). A retrieval algorithm is applied to the data acquired with a table look up technique, similar to that of the operational POLDER algorithm, to provide a first guess of the complex refractive index, optical depth and size distribution of the smoke particles together with cloud droplet size and optical depth. A subsequent iterative fitting procedure, where the fact that the doubling/adding method allows the construction of the Green's function for the radiative transfer equation, is used to obtain an efficient and statistically optimal estimate of the aerosol and cloud retrieval parameters. These retrieval parameters are evaluated against in situ observations, when available, and the optical depth and

  6. Applications of the Hyper Angular Rainbow Polarimeter (HARP) instrument from aircraft and from space

    Science.gov (United States)

    Martins, J. V.; Fernandez Borda, R. A.; McBride, B.; Remer, L. A.; Barbosa, H. M.; Dubovik, O.

    2017-12-01

    The remote sensing of aerosol and cloud microphysics is essential for the global assessment of aerosol and cloud properties. Current spectral techniques utilized by MODIS, VIIRS and similar sensors lack details on the retrieval of the cloud and aerosol particle microphysical properties desired by the scientific community. Multi-spectral hyperangular polarization measurements provide enough information for this additional microphysical retrievals. The HARP (HyperAngular Rainbow Polarimeter) is a compact and modular imaging instrument with wide Field Of View (94 deg cross track and up to 114 degrees along track) and up to 60 along track viewing angles. Spectrally, HARP is envisioned to have modules in the UV, VNIR and SWIR ranges. Currently there are two existing HARP VNIR sensors, for airborne (AirHARP) and space-borne applications respectively, both with 4 wavelengths centered at 440, 550, 670, and 865nm. The space-borne HARP sensor has been designed for a 3U CubeSat satellite currently scheduled for launch to the International Space Station in January 2018 and to be released as a free flying satellite shortly after. At this orbit HARP will provide pixel resolution at the ground of about 400m, which will be binned to coarse resolutions (e.g. 2.5 Km) for data rate reduction. The AirHARP instrument has recently flown in the NASA Langley UC12 aircraft during the LMOS (Lake Michigan Ozone Study) collecting a large data set on aerosol, clouds, and surface properties. AirHARP will also fly in the ACEPOL campaign on board the NASA ER2 aircraft in October/November 2017. These campaigns are supporting HARP's algorithm development and validation in preparation to HARP's Cubesat launch and possibly other HARP space-borne missions. This presentation will describe details of the HARP and AirHARP instruments, as well and preliminary results with level 1 and level 2 data collected during the LMOS and the ACEPOL aircraft campaigns showing clouds and aerosol retrieval results.

  7. Evidence of correlation between TGFBR2 gene expression mediated by NF-kB signaling pathways and Kawasaki disease in children.

    Science.gov (United States)

    Gao, Qinling; Yuan, Shuhua; Yuan, Dawei

    2017-09-15

    We explored the correlation between the TGFBR2 gene that is mediated by NF-kb signaling pathways and the pathogenesis of Kawasaki disease in children. In this study, 43 children with Kawasaki disease from April 2014 to January 2016 at our hospital were selected as the observation group, and 42 healthy children were selected as the control group. The mRNA expression levels of NF-kb gene and TGFBR2 gene in different groups were detected using fluorescence quantitative PCR. The protein expression levels of the NF-kb and TGFBR2 were detected using enzyme-linked immunosorbent assay (ELISA) in different groups. The expression levels of NF-kb and TGFBR2 in the observation group and the control group were detected using immunohistochemistry. Compared to the control group, the mRNA expression levels of NF-kb and TGFBR2 were 12.3 times and 27.5 times as high as those in the control group respectively and there were significant differences between the two groups (p<0.05). ELISA results showed that there were significant differences between the protein expression levels of NF-kb and TGFBR2 in the control group (0.87±0.12, 1.25±0.18) ug/l and those in the observation group (3.27±0.17, 8.16±0.22) ug/l (p<0.05). Western-blotting results showed that the expression levels of the NF-kB and TGFBR2 in children with Kawasaki disease were significantly higher than those in healthy subjects (p<0.05). Immunohistochemistry results showed that the positive cell rate of TGFBR2 (89.7%) was significantly higher in children with Kawasaki disease than that in healthy children (4.5%); there was significant difference between the two groups (p<0.05). The TGFBR2 may be involved in the pathogenesis of Kawasaki disease in children through NF-kB signaling pathways.

  8. Development of fast data processing electronics for a stacked x-ray detector system with application as a polarimeter

    Science.gov (United States)

    Maier, Daniel; Dick, Jürgen; Distratis, Giuseppe; Kendziorra, Eckhard; Santangelo, Andrea; Schanz, Thomas; Tenzer, Christoph; Warth, Gabriele

    2012-09-01

    We have assembled a stacked setup consisting of a soft and hard X-ray detector with cooling capability and control-, readout-, and data processing electronics at the Institut für Astronomie und Astrophysik Tübingen (IAAT). The detector system is a 64 ×64 DePFET-Matrix in front of a CdTe-Caliste module. The detectors were developed at the Max-Planck Institute Semiconductor Laboratory (HLL) in Neuperlach and the Commissariat a l'Energie Atomique (CEA) in Saclay, respectively. In this combined structure the DePFET detector works as Low Energy Detector (LED) while the Caliste module (HED) only detects the high energy photons that have passed through the LED. In this work we present the current status of the setup. Furthermore, an intended application of the detector system as a polarimeter is described.

  9. A solar magnetic and velocity field measurement system for Spacelab 2: The solar optical universal polarimeter (SOUP)

    Science.gov (United States)

    Tarbell, Theodore D.; Title, Alan M.

    1992-08-01

    The Solar Optical Universal Polarimeter flew on the Shuttle Mission Spacelab 2 (STS-51F) in August, 1985, and collected historic solar observations. SOUP is the only solar telescope on either a spacecraft or balloon which has delivered long sequences of diffraction-limited images. These movies led to several discoveries about the solar atmosphere which were published in the scientific journals. After Spacelab 2, reflights were planned on the Space Shuttle Sunlab Mission, which was cancelled after the Challenger disaster, and on balloon flights, which were also cancelled for funding reasons. In the meantime, the instrument was used in a productive program of ground-based observing, which collected excellent scientific data and served as instrument tests. This report gives an overview of the history of the SOUP program, the scientific discoveries, and the instrument design and performance.

  10. The IMaX polarimeter for the solar telescope SUNRISE of the NASA long duration balloon program

    Science.gov (United States)

    Alvarez-Herrero, A.; Martínez-Pillet, V.; Del Toro Iniesta, J. C.; Domingo, V.

    2010-06-01

    On June 8th 2009 the SUNRISE mission was successfully launched. This mission consisted of a 1m aperture solar telescope on board of a stratospheric balloon within the Long Duration Balloon NASA program. The flight followed the foreseen circumpolar trajectory over the Artic and the duration was 5 days and 17 hours. One of the two postfocal instruments onboard was IMaX, the Imaging Magnetograph eXperiment. This instrument is a solar magnetograph which is a diffraction limited imager capable to resolve 100 km on the solar surface, and simultaneously a high sensitivity polarimeter (Aeroespacial field and it is an important precedent for future space missions such as Solar Orbiter from ESA. Among these novel technologies the utilization of Liquid Crystal Variable Retarders (LCVRs) as polarization modulators and a LiNbO3 etalon as tunable spectral filter are remarkable. Currently the data obtained is being analyzed and the preliminary results show unprecedented information about the solar dynamics.

  11. Overexpression of LncRNA AC067945.2 Down-Regulates Collagen Expression in Skin Fibroblasts and Possibly Correlates with the VEGF and Wnt Signalling Pathways.

    Science.gov (United States)

    Chen, Ling; Li, Jingyun; Li, Qian; Li, Xue; Gao, Yanli; Hua, Xiangdong; Zhou, Bei; Li, Jun

    2018-01-01

    Long non-coding RNAs (lncRNAs) are thought to play crucial roles in human diseases. However, the function of lncRNAs in hypertrophic scar formation remains poorly understood. Utilizing qRT-PCR, we explored the expression changes of AC067945.2. Overexpression of AC067945.2 in normal skin fibroblasts was performed by transient plasmid transfection. Western blot was used to check the proteins' expression changes. Cell Counting Kit-8 (CCK-8) assay and Annexin V/7-AAD staining were used to examine cell proliferation and apoptosis, respectively. mRNA-seq was applied to dissect the differentially expressed mRNAs in AC067945.2 overexpressed cells. We also performed ELISA to detect the VEGF secretion. AC067945.2 was down-regulated in hypertrophic scar tissues. Overexpression of AC067945.2 did not affect cell proliferation, but it mildly promoted early apoptosis in normal skin fibroblasts. Furthermore, AC067945.2 overexpression inhibited the expression of COL1A1, COL1A2, COL3A1 and α-SMA proteins. Transforming growth factor-β1 (TGF-β1) could inhibit the expression of AC067945.2. Based on mRNA-seq data, compared with mRNAs in the control group, 138 mRNAs were differentially expressed, including 14 up-regulated and 124 down-regulated transcripts, in the AC067945.2 overexpression group. Gene ontology and pathway analyses revealed that AC067945.2 overexpression was correlated with developmental processes, binding, extracellular region, and the vascular endothelial cell growth factor (VEGF) and Wnt signalling pathways. ELISA confirmed that AC067945.2 overexpression could repress VEGF secretion. Taken together, our data uncovered the functions of a novel lncRNA AC067945.2, which might help us understand the mechanisms regulated by AC067945.2 in the pathogenesis of hypertrophic scar formation. © 2018 The Author(s). Published by S. Karger AG, Basel.

  12. Geometric correlations and multifractals

    International Nuclear Information System (INIS)

    Amritkar, R.E.

    1991-07-01

    There are many situations where the usual statistical methods are not adequate to characterize correlations in the system. To characterize such situations we introduce mutual correlation dimensions which describe geometric correlations in the system. These dimensions allow us to distinguish between variables which are perfectly correlated with or without a phase lag, variables which are uncorrelated and variables which are partially correlated. We demonstrate the utility of our formalism by considering two examples from dynamical systems. The first example is about the loss of memory in chaotic signals and describes auto-correlations while the second example is about synchronization of chaotic signals and describes cross-correlations. (author). 19 refs, 6 figs

  13. Analiza kontinualnih frekvencijski modulisanih radarskih signala primenom vremensko-frekvencijskih transformacija i korelacionih tehnika / FMCW radar signal analysis by time-frequency representations and correlation techniques

    Directory of Open Access Journals (Sweden)

    Slobodan Simić

    2007-10-01

    Full Text Available U radu su analizirana dva metoda za detekciju i procenu parametara radarskih signala s malom verovatnoćom presretanja, pri čemu ne postoji saradnja između prijemnika i predajnika. Prvi algoritam čini analiza signala pomoću vremensko-frekvencijskih transformacija zajedno sa tehnikama za prepoznavanje oblika. U osnovi drugog algoritma detekcije je procena periodične autokorelacione funkcije. Analizirani su kontinualni frekvencijski modulisani radarski signali (FMCW, često primenjivani u radarima s malom verovatnoćom presretanja. Korišćeni su test-signali, dobijeni eksperimentalnim putem. Realizovan je eksperiment s realnim predajnikom i prijemnikom FMCW signala, a rezultati obrade primljenih signala prikazani su u radu. / Two LPI signal detection and parameter estimation methods are analyzed in a non-cooperative context. The first method is based on the time-frequency signal analysis along with pattern recognition techniques. The second one is based on the estimation of a periodic autocorrelation function. Frequency modulation continuous wave (FMCW signals are analyzed as a class of waveforms often used in LPI radars. Experimentally obtained signals are used in tests. An experiment with a real FMCW signal transceiver and a receiver is carried out and the obtained signal analysis results are presented.

  14. Statistics of the derivatives of complex signal derived from Riesz transform and its application to pseudo-Stokes vector correlation for speckle displacement measurement

    DEFF Research Database (Denmark)

    Zhang, Shun; Yang, Yi; Hanson, Steen Grüner

    2015-01-01

    As an improvement of the well-known intensity correlation used in conventional electronic speckle photography, we have proposed a new technique, to the best of our knowledge, for displacement measurement referred to as pseudo-Stokes vector correlation (PSVC). To provide a theoretical background f...

  15. Driving gradual endogenous c-myc overexpression by flow-sorting: intracellular signaling and tumor cell phenotype correlate with oncogene expression

    DEFF Research Database (Denmark)

    Knudsen, Kasper Jermiin; Holm, G.M.N.; Krabbe, J.S.

    2009-01-01

    cells than in the nonsorted cell population. To our knowledge, this is the first in vitro system allowing functional coupling between mitogenic signaling by a well-defined growth factor and gradual overexpression of the normal, endogenous c-myc gene. Thus, our flow-sorting approach provides...

  16. Multichannel spin polarimeter for energy- and angle-dispersive photoemission measurements; Vielkanal-Spinpolarimeter fuer energie- und winkeldispersive Photoemissionsmessungen

    Energy Technology Data Exchange (ETDEWEB)

    Kolbe, Michaela

    2011-09-09

    Spin polarization measurements of free electrons remain challenging since their first realization by Mott. The relevant quantity of a spin polarimeter is its figure of merit, FoM=S{sup 2}I/I{sub 0}, with the asymmetry function S and the ratio between scattered and primary intensity I/I{sub 0}. State-of-the-art devices are based on single-channel scattering (spin-orbit or exchange interaction) which is characterized by FoM {approx_equal}10{sup -4}. On the other hand, modern hemispherical analyzers feature an efficient multichannel detection of spin-integral intensity with more than 10{sup 4} data points simultaneously. In comparison between spin-resolved and spin-integral electron spectroscopy we are thus faced with a difference in counting efficiency by 8 orders of magnitude. The present work concentrates on the development and investigation of a novel technique for increasing the efficiency in spin-resolved electron spectroscopy by multichannel detection. The spin detector was integrated in a {mu}-metal shielded UHV-chamber and mounted behind a conventional hemispherical analyzer. The electrostatic lens system's geometry was determined by electron-optical simulations. The basic concept is the k {sub parallel} -conserving elastic scattering of the (0,0)-beam on a W(100) scattering crystal under 45 impact angle. It could be demonstrated that app. 960 data points (15 energy and 64 angular points) could be displayed simultaneously on a delayline detector in an energy interval of {approx_equal}3 eV. This leads to a two-dimensional figure of merit of FoM{sub 2D}=1.7. Compared to conventional spin detectors, the new type is thus characterized by a gain in efficiency of 4 orders of magnitude. The operational reliability of the new spin polarimeter could be proven by measurements with a Fe/MgO(100) and O p(1 x 1)/Fe(100)-sample, where results from the literature were reproduced with strongly decreased measuring time. Due to the high intensity it becomes possible, to

  17. Optical Alignment of the Chromospheric Lyman-Alpha SpectroPolarimeter using Sophisticated Methods to Minimize Activities under Vacuum

    Science.gov (United States)

    Giono, G.; Katsukawa, Y.; Ishikawa, R.; Narukage, N.; Kano, R.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.; hide

    2016-01-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding-rocket instrument developed at the National Astronomical Observatory of Japan (NAOJ) as a part of an international collaboration. The in- strument main scientific goal is to achieve polarization measurement of the Lyman-alpha line at 121.56 nm emitted from the solar upper-chromosphere and transition region with an unprecedented 0.1% accuracy. For this purpose, the optics are composed of a Cassegrain telescope coated with a "cold mirror" coating optimized for UV reflection and a dual-channel spectrograph allowing for simultaneous observation of the two orthogonal states of polarization. Although the polarization sensitivity is the most important aspect of the instrument, the spatial and spectral resolutions of the instrument are also crucial to observe the chromospheric features and resolve the Ly- pro les. A precise alignment of the optics is required to ensure the resolutions, but experiments under vacuum conditions are needed since Ly-alpha is absorbed by air, making the alignment experiments difficult. To bypass this issue, we developed methods to align the telescope and the spectrograph separately in visible light. We will explain these methods and present the results for the optical alignment of the CLASP telescope and spectrograph. We will then discuss the combined performances of both parts to derive the expected resolutions of the instrument, and compare them with the flight observations performed on September 3rd 2015.

  18. Combined neural network/Phillips–Tikhonov approach to aerosol retrievals over land from the NASA Research Scanning Polarimeter

    Directory of Open Access Journals (Sweden)

    A. Di Noia

    2017-11-01

    Full Text Available In this paper, an algorithm for the retrieval of aerosol and land surface properties from airborne spectropolarimetric measurements – combining neural networks and an iterative scheme based on Phillips–Tikhonov regularization – is described. The algorithm – which is an extension of a scheme previously designed for ground-based retrievals – is applied to measurements from the Research Scanning Polarimeter (RSP on board the NASA ER-2 aircraft. A neural network, trained on a large data set of synthetic measurements, is applied to perform aerosol retrievals from real RSP data, and the neural network retrievals are subsequently used as a first guess for the Phillips–Tikhonov retrieval. The resulting algorithm appears capable of accurately retrieving aerosol optical thickness, fine-mode effective radius and aerosol layer height from RSP data. Among the advantages of using a neural network as initial guess for an iterative algorithm are a decrease in processing time and an increase in the number of converging retrievals.

  19. The IMaX polarimeter for the solar telescope SUNRISE of the NASA long duration balloon program

    Directory of Open Access Journals (Sweden)

    Domingo V.

    2010-06-01

    Full Text Available On June 8th 2009 the SUNRISE mission was successfully launched. This mission consisted of a 1m aperture solar telescope on board of a stratospheric balloon within the Long Duration Balloon NASA program. The flight followed the foreseen circumpolar trajectory over the Artic and the duration was 5 days and 17 hours. One of the two postfocal instruments onboard was IMaX, the Imaging Magnetograph eXperiment. This instrument is a solar magnetograph which is a diffraction limited imager capable to resolve 100 km on the solar surface, and simultaneously a high sensitivity polarimeter (<10-3 and a high resolution spectrograph (bandwidth <70mÅ. The magnetic vectorial map can be extracted thanks to the well-know Zeeman effect, which takes place in the solar atoms, allowing to relate polarization and spectral measurements to magnetic fields. The technological challenge of the IMaX development has a special relevance due to the utilization of innovative technologies in the Aeroespacial field and it is an important precedent for future space missions such as Solar Orbiter from ESA. Among these novel technologies the utilization of Liquid Crystal Variable Retarders (LCVRs as polarization modulators and a LiNbO3 etalon as tunable spectral filter are remarkable. Currently the data obtained is being analyzed and the preliminary results show unprecedented information about the solar dynamics.

  20. The Effect of Trifluoroethanol and Glycerol on the Thermal Properties of Collagen Using Optical Displacement-Enhanced Heterodyne Polarimeter

    Directory of Open Access Journals (Sweden)

    Chien-Ming Wu

    2015-11-01

    Full Text Available An angular displacement-enhanced heterodyne polarimeter has been employed to investigate the interplay between trifluoroethanol (TFE and glycerol on the thermal denaturation of type I collagen. The concentration of the collagen solution was fixed at 0.341 (mg/mL, and was heated from 25 °C to 55 °C. TFE solutions with concentrations of 5%, 10%, 15%, 20%, 40% and 80% (v/v were prepared and the phase change was recorded for the determination of thermal denaturation. It was observed that the thermal denaturation temperature (Td is decreased with increasing TFE concentration due to the partial cleavage of the triple-helical structure. With TFE concentration higher than 20% (v/v, the degree of optical rotation appears to be nearly the same, reflecting that the collagen triple helices have been completely destructed. Moreover, the addition of glycerol in inhibiting the thermal denaturation of collagen is investigated. It has been shown that glycerol can improve the thermal denaturation of both collagen and TFE-mixed collagen. Experimental results show that, in the presence of 2 M glycerol, the Td of collagen remained at around 41.9 °C, meanwhile the Td of 20% (v/v TFE-mixed collagen is significantly restored to 32.8 °C.

  1. Is there any correlation between model-based perfusion parameters and model-free parameters of time-signal intensity curve on dynamic contrast enhanced MRI in breast cancer patients?

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Boram; Kang, Doo Kyoung; Kim, Tae Hee [Ajou University School of Medicine, Department of Radiology, Suwon, Gyeonggi-do (Korea, Republic of); Yoon, Dukyong [Ajou University School of Medicine, Department of Biomedical Informatics, Suwon (Korea, Republic of); Jung, Yong Sik; Kim, Ku Sang [Ajou University School of Medicine, Department of Surgery, Suwon (Korea, Republic of); Yim, Hyunee [Ajou University School of Medicine, Department of Pathology, Suwon (Korea, Republic of)

    2014-05-15

    To find out any correlation between dynamic contrast-enhanced (DCE) model-based parameters and model-free parameters, and evaluate correlations between perfusion parameters with histologic prognostic factors. Model-based parameters (Ktrans, Kep and Ve) of 102 invasive ductal carcinomas were obtained using DCE-MRI and post-processing software. Correlations between model-based and model-free parameters and between perfusion parameters and histologic prognostic factors were analysed. Mean Kep was significantly higher in cancers showing initial rapid enhancement (P = 0.002) and a delayed washout pattern (P = 0.001). Ve was significantly lower in cancers showing a delayed washout pattern (P = 0.015). Kep significantly correlated with time to peak enhancement (TTP) (ρ = -0.33, P < 0.001) and washout slope (ρ = 0.39, P = 0.002). Ve was significantly correlated with TTP (ρ = 0.33, P = 0.002). Mean Kep was higher in tumours with high nuclear grade (P = 0.017). Mean Ve was lower in tumours with high histologic grade (P = 0.005) and in tumours with negative oestrogen receptor status (P = 0.047). TTP was shorter in tumours with negative oestrogen receptor status (P = 0.037). We could acquire general information about the tumour vascular physiology, interstitial space volume and pathologic prognostic factors by analyzing time-signal intensity curve without a complicated acquisition process for the model-based parameters. (orig.)

  2. Increased signal intensity at the proximal patellar tendon: correlation between MR imaging and histology in eight cadavers and clinical MR imaging studies

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Seong Jong; Jin, Wook; Yoon, So Hee; Park, So Young [Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Department of Radiology, Seoul (Korea, Republic of); Park, Yong-Koo [Kyung Hee University Medical Center, Department of Pathology, Seoul (Korea, Republic of); Kim, Gou Young [Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Department of Pathology, Seoul (Korea, Republic of); Lee, Jung Eun; Park, Ji Seon; Ryu, Kyung Nam [Kyung Hee University Medical Center, Department of Radiology, Seoul (Korea, Republic of)

    2015-10-15

    We set out to investigate the cause of persistently increased signal intensity (SI) in the posterior portion of the proximal patellar tendon (pPT) on T1-weighted images (T1WI). MR imaging was performed in eight cadavers, followed by gross histological examination. In addition, 84 patients without trauma history or anterior knee pain were included to compare the SI of the PTs. The patients were divided according to their age, sex, and Kellgren-Lawrence (KL) grades. The length and thickness of the increased SI portion in the pPT and whole PT (wPT) on T1WI were recorded. Histological specimens demonstrated that the adipose tissue, vessels, and perivascular connective tissue invaginated into the posterior portion of the pPT. This histological anatomy corresponded to the pPT signal change on MR imaging. There was linear and interdigitating increased SI of the pPT in all of the 84 patients (100 %). There were no differences in the lengths and thicknesses of the increased SI portion of pPTs and wPTs according to age, sex, and KL grade (all p > 0.05). The increased SI of the pPT on T1WI and fluid-sensitive MR images results from invaginating fat, vessels, and perivascular connective tissue. It is not pathological, but a normal and common finding. (orig.)

  3. Constitutive activation of jasmonate signaling in an Arabidopsis mutant correlates with enhanced resistance to Erysiphe cichoracearum, Pseudomonas syringae, and Myzus persicae.

    Science.gov (United States)

    Ellis, Christine; Karafyllidis, Ioannis; Turner, John G

    2002-10-01

    In Arabidopsis spp., the jasmonate (JA) response pathway generally is required for defenses against necrotrophic pathogens and chewing insects, while the salicylic acid (SA) response pathway is generally required for specific, resistance (R) gene-mediated defenses against both biotrophic and necrotrophic pathogens. For example, SA-dependent defenses are required for resistance to the biotrophic fungal pathogen Erysiphe cichoracearum UCSC1 and the bacterial pathogen Pseudomonas syringae pv. maculicola, and also are expressed during response to the green peach aphid Myzus persicae. However, recent evidence indicates that the expression of JA-dependent defenses also may confer resistance to E. cichoracearum. To confirm and to extend this observation, we have compared the disease and pest resistance of wild-type Arabidopsis plants with that of the mutants coil, which is insensitive to JA, and cev1, which has constitutive JA signaling. Measurements of the colonization of these plants by E. cichoracearum, P. syringae pv. maculicola, and M. persicae indicated that activation of the JA signal pathway enhanced resistance, and was associated with the activation of JA-dependent defense genes and the suppression of SA-dependent defense genes. We conclude that JA and SA induce alternative defense pathways that can confer resistance to the same pathogens and pests.

  4. (Modic) signal alterations of vertebral endplates and their correlation to a minimally invasive treatment of lumbar disc herniation using epidural injections; (Modic-)Signalveraenderungen vertebraler Endplatten und ihr Bezug zu einer minimalinvasiven Injektionstherapie lumbaler Bandscheibenvorfaelle

    Energy Technology Data Exchange (ETDEWEB)

    Liphofer, J.P.; Becker, G.T.; Koester, O. [Inst. fuer Diagnostische und Interventionelle Radiologie und Nuklearmedizin, St. Josef-Hospital Bochum (Germany); Theodoridis, T. [Klinik fuer Orthopaedie und Unfallchirurgie, St. Josef-Hospital Bochum (Germany); Schmid, G. [Klinik fuer Diagnostische und Interventionelle Radiologie, Johanna-Etienne-Krankenhaus Neuss (Germany)

    2006-11-15

    Purpose: To study the influence of (Modic) signal alterations (SA) of the cartilage endplate (CEP) of vertebrae L3-S1 on the outcome of an in-patient minimally invasive treatment (MIT), using epidural injections on patients with lumbar disc herniation (LDH). Materials and Methods: The MR images of 59 consecutive patients with LDH within segments L3/L4-L5/S1 undergoing in-patient minimally invasive treatment with epidural injections were evaluated in a clinical study. The (Modic) signal alterations of the CEP were recorded using T1- and T2-weighted sagittal images. On the basis of the T2-weighted sagittal images, the extension and distribution of the SA were measured by dividing each CEP into 9 areas. The outcome of the MIT was recorded using the Oswestry Disability Index (ODI) before and after therapy and in a 3-month follow-up. Within a subgroup of patients (n=35), the distribution and extension of the signal alterations were correlated with the development of the ODI. Results: Segments with LDH showed significantly more (p<0.001) SA of the CEP than segments without LDH. Although the extension of the SA was not dependent on sex, it did increase significantly with age (p=0.017). The outcome after MIT did not depend on the sex and age of the patients or on the type od LDH. The SA extension tended to have a negative correlation with the outcome after MIT after 3 months (p=0.071). A significant negative correlation could be established between the SA extension in the central section of the upper endplate and the outcome after 3 months (p=0.019). (orig.)

  5. Temporal Patterns in Sheep Fetal Heart Rate Variability Correlate to Systemic Cytokine Inflammatory Response: A Methodological Exploration of Monitoring Potential Using Complex Signals Bioinformatics.

    Directory of Open Access Journals (Sweden)

    Christophe L Herry

    Full Text Available Fetal inflammation is associated with increased risk for postnatal organ injuries. No means of early detection exist. We hypothesized that systemic fetal inflammation leads to distinct alterations of fetal heart rate variability (fHRV. We tested this hypothesis deploying a novel series of approaches from complex signals bioinformatics. In chronically instrumented near-term fetal sheep, we induced an inflammatory response with lipopolysaccharide (LPS injected intravenously (n = 10 observing it over 54 hours; seven additional fetuses served as controls. Fifty-one fHRV measures were determined continuously every 5 minutes using Continuous Individualized Multi-organ Variability Analysis (CIMVA. CIMVA creates an fHRV measures matrix across five signal-analytical domains, thus describing complementary properties of fHRV. We implemented, validated and tested methodology to obtain a subset of CIMVA fHRV measures that matched best the temporal profile of the inflammatory cytokine IL-6. In the LPS group, IL-6 peaked at 3 hours. For the LPS, but not control group, a sharp increase in standardized difference in variability with respect to baseline levels was observed between 3 h and 6 h abating to baseline levels, thus tracking closely the IL-6 inflammatory profile. We derived fHRV inflammatory index (FII consisting of 15 fHRV measures reflecting the fetal inflammatory response with prediction accuracy of 90%. Hierarchical clustering validated the selection of 14 out of 15 fHRV measures comprising FII. We developed methodology to identify a distinctive subset of fHRV measures that tracks inflammation over time. The broader potential of this bioinformatics approach is discussed to detect physiological responses encoded in HRV measures.

  6. Site-specific glycoprofiling of N-linked glycopeptides using MALDI-TOF MS: strong correlation between signal strength and glycoform quantities

    DEFF Research Database (Denmark)

    Thaysen-Andersen, Morten; Mysling, Simon; Højrup, Peter

    2009-01-01

    Site-specific glycoprofiling of N-linked glycopeptides using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an emerging technique, but its quantitative accuracy lacks documentation. Thus, a systematic study of widely different glycopeptides was perf......Site-specific glycoprofiling of N-linked glycopeptides using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an emerging technique, but its quantitative accuracy lacks documentation. Thus, a systematic study of widely different glycopeptides...... quantitation (correlation coefficient r = 0.9958, n = 5) when evaluated against a normal phase HPLC 2-AB glycan profile. Similarly, precise quantitation was observed for various forms of N-glycans (free, permethylated, and fluorescence-labeled) using MS. In addition, three different sialoglycopeptides from...... fetuin were site-specifically profiled, and good correlation between peak intensities and relative abundances was found with only a minor loss of sialic acids (r = 0.9664, n = 5). For glycopeptide purification, a range of hydrophilic and graphite materials packed in microcolumn format proved capable...

  7. Moeller scattering with unpolarized electrons for the development of a Moeller polarimeter at ELSA

    International Nuclear Information System (INIS)

    Hueffer, C.

    1992-07-01

    In future experiments with polarized electrons are planned at ELSA, so it is necessary to measure the polarisation of the extracted electron beam. One possibility is to use the method of Moeller-scattering. A suitable arrangement with two lucite Cerenkov-detectors has been investigated and Moeller-scattering with unpolarized electrons has been studied. A low noise-to-signal-ratio in the time spectra allowed to separate Moeller events from background. Therefore it was possible to observe the linear dependence of Moeller-scattering-events on the atomic number of the target foil and on the current of the extracted electron beam. With regard to planned experiments it was important to show that the separation of the Moeller-electrons from the primary beam by the use of one single dipole magnet has been succesful. (orig.) [de

  8. Design and Testing of the MIT-Bates Stern-Gerlach Polarimeter Cavity

    CERN Document Server

    Cameron, P; Luccio, A U; MacKay, W W

    2005-01-01

    Historically, beam polarization measurement has been accomplished by scattering experiments, with the attendant complexity of target and detector installation and operation, and smallness and uncertainty of analyzing powers. The purpose of the present effort is to accomplish fast and accurate polarization measurement not as a scattering experiment, but rather as conventional beam instrumentation, with a resonant cavity pickup. This requires that the coupling of the beam magnetic moment to the pickup be enhanced to bring the signal above the noise floor, and that coupling of the beam charge to the pickup be diminished to reduce the dynamic range problem. We discuss details of cavity design that have been implemented to accomplish these ends. Presently, it is planned to install the cavity in the Bates Ring in early May of this year. Beyond polarimetry, successful polarization measurement will verify the underlying principles, and by pickup/kicker reciprocity will open the serious consideration of the possibilit...

  9. Design of the Telescope Truss and Gondola for the Balloon-Borne X-ray Polarimeter X-Calibur

    Science.gov (United States)

    Kislat, Fabian; Beheshtipour, Banafsheh; Dowkontt, Paul; Guarino, Victor; Lanzi, R. James; Okajima, Takashi; Braun, Dana; Cannon, Scott; de Geronimo, Gialuigi; Heatwole, Scott; Hoorman, Janie; Li, Shaorui; Mori, Hideyuki; Shreves, Christopher M.; Stuchlik, David; Krawczynski, Henric

    X-ray polarimetry has seen a growing interest in recent years. Improvements in detector technology and focusing X-ray optics now enable sensitive astrophysical X-ray polarization measurements. These measurements will provide new insights into the processes at work in accreting black holes, the emission of X-rays from neutron stars and magnetars, and the structure of AGN jets. X-Calibur is a balloon-borne hard X-ray scattering polarimeter. An X-ray mirror with a focal length of 8m focuses X-rays onto the detector, which consists of a plastic scattering element surrounded by Cadmium-Zinc-Telluride detectors, which absorb and record the scattered X-rays. Since X-rays preferentially scatter perpendicular to their polarization direction, the polarization properties of an X-ray beam can be inferred from the azimuthal distribution of scattered X-rays. A close alignment of the X-ray focal spot with the center of the detector is required in order to reduce systematic uncertainties and to maintain a high photon detection efficiency. This places stringent requirements on the mechanical and thermal stability of the telescope structure. During the flight on a stratospheric balloon, X-Calibur makes use of the Wallops Arc-Second Pointer (WASP) to point the telescope at astrophysical sources. In this paper, we describe the design, construction, and test of the telescope structure, as well as its performance during a 25-h flight from Ft. Sumner, New Mexico. The carbon fiber-aluminum composite structure met the requirements set by X-Calibur and its design can easily be adapted for other types of experiments, such as X-ray imaging or spectroscopic telescopes.

  10. Individual variation and hormonal modulation of a sodium channel beta subunit in the electric organ correlate with variation in a social signal.

    Science.gov (United States)

    Liu, He; Wu, Ming-Ming; Zakon, Harold H

    2007-09-01

    The sodium channel beta1 subunit affects sodium channel gating and surface density, but little is known about the factors that regulate beta1 expression or its participation in the fine control of cellular excitability. In this study we examined whether graded expression of the beta1 subunit contributes to the gradient in sodium current inactivation, which is tightly controlled and directly related to a social behavior, the electric organ discharge (EOD), in a weakly electric fish Sternopygus macrurus. We found the mRNA and protein levels of beta1 in the electric organ both correlate with EOD frequency. We identified a novel mRNA splice form of this gene and found the splicing preference for this novel splice form also correlates with EOD frequency. Androgen implants lowered EOD frequency and decreased the beta1 mRNA level but did not affect splicing. Coexpression of each splice form in Xenopus oocytes with either the human muscle sodium channel gene, hNav1.4, or a Sternopygus ortholog, smNav1.4b, sped the rate of inactivation of the sodium current and shifted the steady-state inactivation toward less negative membrane potentials. The translational product of the novel mRNA splice form lacks a previously identified important tyrosine residue but still functions normally. The properties of the fish alpha and coexpressed beta1 subunits in the oocyte replicate those of the electric organ's endogenous sodium current. These data highlight the role of ion channel beta subunits in regulating cellular excitability.

  11. Gas-correlation lidar

    OpenAIRE

    Edner, H; Svanberg, Sune; Uneus, L; Wendt, W

    1984-01-01

    Basic principles for the extension of gas-correlation techniques to the lidar situation are discussed. Favorable signal-to-noise ratios and relaxed laser requirements characterize the technique. Preliminary experiments on atomic mercury are reported.

  12. Does basal metabolic rate contain a useful signal? Mammalian BMR allometry and correlations with a selection of physiological, ecological, and life-history variables.

    Science.gov (United States)

    White, Craig R; Seymour, Roger S

    2004-01-01

    Basal metabolic rate (BMR, mL O2 h(-1)) is a useful measurement only if standard conditions are realised. We present an analysis of the relationship between mammalian body mass (M, g) and BMR that accounts for variation associated with body temperature, digestive state, and phylogeny. In contrast to the established paradigm that BMR proportional to M3/4, data from 619 species, representing 19 mammalian orders and encompassing five orders of magnitude variation in M, show that BMR proportional to M2/3. If variation associated with body temperature and digestive state are removed, the BMRs of eutherians, marsupials, and birds do not differ, and no significant allometric exponent heterogeneity remains between orders. The usefulness of BMR as a general measurement is supported by the observation that after the removal of body mass effects, the residuals of BMR are significantly correlated with the residuals for a variety of physiological and ecological variables, including maximum metabolic rate, field metabolic rate, resting heart rate, life span, litter size, and population density.

  13. Design and testing of the MIT-bates Stern-Gerlach polarimeter cavity

    International Nuclear Information System (INIS)

    Cameron, P.; D'Imperio, N.; Luccio, A.U.; MacKay, W.W.; Conte, M.; Franklin, W.A.; Ihloff, E.; Zwart, T.; Goldberg, D.A.

    2005-01-01

    The full text of publication follows. Historically, beam polarization measurement has been accomplished by scattering experiments, with the attendant complexity of target and detector installation and operation, and smallness and uncertainty of analyzing powers. The purpose of the present effort is to accomplish fast and accurate polarization measurement not as a scattering experiment, but rather as conventional beam instrumentation, with a resonant cavity pickup. This requires that the coupling of the beam magnetic moment to the pickup be enhanced to bring the signal above the noise floor, and that coupling of the beam charge to the pickup be diminished to reduce the dynamic range problem. We discuss details of cavity design that have been implemented to accomplish these ends. Presently, it is planned to install the cavity in the Bates Ring in early May of this year. Beyond polarimetry, successful polarization measurement will verify the underlying principles, and by pickup/kicker reciprocity will open the serious consideration of the possibility of polarizing the full-energy LHC proton beams in-situ. (authors)

  14. Neurobehavioral Deficits in a Rat Model of Recurrent Neonatal Seizures Are Prevented by a Ketogenic Diet and Correlate with Hippocampal Zinc/Lipid Transporter Signals.

    Science.gov (United States)

    Tian, Tian; Ni, Hong; Sun, Bao-liang

    2015-10-01

    The ketogenic diet (KD) has been shown to be effective as an antiepileptic therapy in adults, but it has not been extensively tested for its efficacy in neonatal seizure-induced brain damage. We have previously shown altered expression of zinc/lipid metabolism-related genes in hippocampus following penicillin-induced developmental model of epilepsy. In this study, we further investigated the effect of KD on the neurobehavioral and cognitive deficits, as well as if KD has any influence in the activity of zinc/lipid transporters such as zinc transporter 3 (ZnT-3), MT-3, ApoE, ApoJ (clusterin), and ACAT-1 activities in neonatal rats submitted to flurothyl-induced recurrent seizures. Postnatal day 9 (P9), 48 Sprague-Dawley rats were randomly assigned to two groups: flurothyl-induced recurrent seizure group (EXP) and control group (CONT). On P28, they were further randomly divided into the seizure group without ketogenic diet (EXP1), seizure plus ketogenic diet (EXP2), the control group without ketogenic diet (CONT1), and the control plus ketogenic diet (CONT2). Neurological behavioral parameters of brain damage (plane righting reflex, cliff avoidance reflex, and open field test) were observed from P35 to P49. Morris water maze test was performed during P51-P57. Then hippocampal mossy fiber sprouting and the protein levels of ZnT3, MT3, ApoE, CLU, and ACAT-1 were detected by Timm staining and Western blot analysis, respectively. Flurothyl-induced neurobehavioral toxicology and aberrant mossy fiber sprouting were blocked by KD. In parallel with these behavioral changes, rats treated with KD (EXP2) showed a significant down-regulated expression of ZnT-3, MT-3, ApoE, clusterin, and ACAT-1 in hippocampus when compared with the non-KD-treated EXP1 group. Our findings provide support for zinc/lipid transporter signals being potential targets for the treatment of neonatal seizure-induced brain damage by KD.

  15. Spatial Autocorrelation Can Generate Stronger Correlations between Range Size and Climatic Niches Than the Biological Signal - A Demonstration Using Bird and Mammal Range Maps.

    Science.gov (United States)

    Boucher-Lalonde, Véronique; Currie, David J

    2016-01-01

    Species' geographic ranges could primarily be physiological tolerances drawn in space. Alternatively, geographic ranges could be only broadly constrained by physiological climatic tolerances: there could generally be much more proximate constraints on species' ranges (dispersal limitation, biotic interactions, etc.) such that species often occupy a small and unpredictable subset of tolerable climates. In the literature, species' climatic tolerances are typically estimated from the set of conditions observed within their geographic range. Using this method, studies have concluded that broader climatic niches permit larger ranges. Similarly, other studies have investigated the biological causes of incomplete range filling. But, when climatic constraints are measured directly from species' ranges, are correlations between species' range size and climate necessarily consistent with a causal link? We evaluated the extent to which variation in range size among 3277 bird and 1659 mammal species occurring in the Americas is statistically related to characteristics of species' realized climatic niches. We then compared how these relationships differed from the ones expected in the absence of a causal link. We used a null model that randomizes the predictor variables (climate), while retaining their broad spatial autocorrelation structure, thereby removing any causal relationship between range size and climate. We found that, although range size is strongly positively related to climatic niche breadth, range filling and, to a lesser extent, niche position in nature, the observed relationships are not always stronger than expected from spatial autocorrelation alone. Thus, we conclude that equally strong relationships between range size and climate would result from any processes causing ranges to be highly spatially autocorrelated.

  16. Spatial Autocorrelation Can Generate Stronger Correlations between Range Size and Climatic Niches Than the Biological Signal — A Demonstration Using Bird and Mammal Range Maps

    Science.gov (United States)

    Boucher-Lalonde, Véronique; Currie, David J.

    2016-01-01

    Species’ geographic ranges could primarily be physiological tolerances drawn in space. Alternatively, geographic ranges could be only broadly constrained by physiological climatic tolerances: there could generally be much more proximate constraints on species’ ranges (dispersal limitation, biotic interactions, etc.) such that species often occupy a small and unpredictable subset of tolerable climates. In the literature, species’ climatic tolerances are typically estimated from the set of conditions observed within their geographic range. Using this method, studies have concluded that broader climatic niches permit larger ranges. Similarly, other studies have investigated the biological causes of incomplete range filling. But, when climatic constraints are measured directly from species’ ranges, are correlations between species’ range size and climate necessarily consistent with a causal link? We evaluated the extent to which variation in range size among 3277 bird and 1659 mammal species occurring in the Americas is statistically related to characteristics of species’ realized climatic niches. We then compared how these relationships differed from the ones expected in the absence of a causal link. We used a null model that randomizes the predictor variables (climate), while retaining their broad spatial autocorrelation structure, thereby removing any causal relationship between range size and climate. We found that, although range size is strongly positively related to climatic niche breadth, range filling and, to a lesser extent, niche position in nature, the observed relationships are not always stronger than expected from spatial autocorrelation alone. Thus, we conclude that equally strong relationships between range size and climate would result from any processes causing ranges to be highly spatially autocorrelated. PMID:27855201

  17. Correlation Functions and Power Spectra

    DEFF Research Database (Denmark)

    Larsen, Jan

    2006-01-01

    The present lecture note is a supplement to the textbook Digital Signal Processing by J. Proakis and D.G. Manolakis used in the IMM/DTU course 02451 Digital Signal Processing and provides an extended discussion of correlation functions and power spectra. The definitions of correlation functions....... It is possible to define correlation functions and associated spectra for aperiodic, periodic and random signals although the interpretation is different. Moreover, we will discuss correlation functions when mixing these basic signal types. In addition, the note include several examples for the purpose...

  18. Correlação entre sinais e sintomas de olho seco em pacientes portadores da síndrome de Sjögren Correlation between signals and symptoms of dry eye in Sjögren's syndrome patients

    Directory of Open Access Journals (Sweden)

    Marcello Novoa Colombo Barboza

    2008-08-01

    Full Text Available OBJETIVO: Estudar, numa determinada população de portadores da síndrome de Sjögren, a correlação entre os sinais e sintomas de olho seco. MÉTODOS: Foi constituído o Grupo Caso, formado por 17 pacientes portadores da síndrome de Sjögren e o Grupo Controle, formado por 25 pacientes normais. Para avaliação dos sintomas foi aplicado o questionário "Ocular Surface Disease Index (OSDI" nos pacientes de ambos os grupos e, em seguida, todos os indivíduos foram submetidos à realização dos testes de Schirmer I e II, coloração da superfície ocular com corante rosa bengala, paquimetria e estesiometria. Para análise das correlações entre sinais e sintomas foi utilizado o teste de correlação de Spearman e para comparação das médias dos valores encontrados no questionário "Ocular Surface Disease Index (OSDI" e nos testes clínicos entre os pacientes dos Grupos, foi utilizado teste t de Student para amostras independentes. RESULTADOS: Os resultados deste estudo evidenciaram fraca correlação entre os sintomas avaliados pelo questionário "Ocular Surface Disease Index (OSDI" e os testes oculares, o que indica que nem todos os pacientes que apresentavam sintomas exuberantes, exibiam testes proporcionalmente alterados. A média da sensibilidade da córnea de ambos os olhos dos pacientes do Grupo Caso esteve estatisticamente reduzida quando comparada à do Grupo Controle. Todos os parâmetros estudados no Grupo Caso apresentaram diferenças estatisticamente significantes (pPURPOSE: To study the correlation between the signals and symptoms of dry eye in Sjögren's syndrome patients. METHODS: We formed the case group with 17 Sjögren's syndrome patients and the control group with 25 normal patients. For evaluation of the symptoms the "Ocular Surface Disease Index (OSDI" questionnaire was applied to both groups and, after that, all the individuals were submitted to the ocular tests: Schirmer I and II, coloration of the ocular surface with

  19. Correlation ion mobility spectroscopy

    Science.gov (United States)

    Pfeifer, Kent B [Los Lunas, NM; Rohde, Steven B [Corrales, NM

    2008-08-26

    Correlation ion mobility spectrometry (CIMS) uses gating modulation and correlation signal processing to improve IMS instrument performance. Closely spaced ion peaks can be resolved by adding discriminating codes to the gate and matched filtering for the received ion current signal, thereby improving sensitivity and resolution of an ion mobility spectrometer. CIMS can be used to improve the signal-to-noise ratio even for transient chemical samples. CIMS is especially advantageous for small geometry IMS drift tubes that can otherwise have poor resolution due to their small size.

  20. Spectral analysis by correlation

    International Nuclear Information System (INIS)

    Fauque, J.M.; Berthier, D.; Max, J.; Bonnet, G.

    1969-01-01

    The spectral density of a signal, which represents its power distribution along the frequency axis, is a function which is of great importance, finding many uses in all fields concerned with the processing of the signal (process identification, vibrational analysis, etc...). Amongst all the possible methods for calculating this function, the correlation method (correlation function calculation + Fourier transformation) is the most promising, mainly because of its simplicity and of the results it yields. The study carried out here will lead to the construction of an apparatus which, coupled with a correlator, will constitute a set of equipment for spectral analysis in real time covering the frequency range 0 to 5 MHz. (author) [fr

  1. Retrograde signaling

    DEFF Research Database (Denmark)

    Kleine, Tatjana; Leister, Dario Michael

    2016-01-01

    The term retrograde signaling refers to the fact that chloroplasts and mitochondria utilize specific signaling molecules to convey information on their developmental and physiological states to the nucleus and modulate the expression of nuclear genes accordingly. Signals emanating from plastids...... of retrograde signaling has since been extended and revised. Elements of several 'operational' signaling circuits have come to light, including metabolites, signaling cascades in the cytosol and transcription factors. Here, we review recent advances in the identification and characterization of retrograde...

  2. Increasing signal intensity within the dentate nucleus and globus pallidus on unenhanced T1W magnetic resonance images in patients with relapsing-remitting multiple sclerosis: correlation with cumulative dose of a macrocyclic gadolinium-based contrast agent, gadobutrol

    International Nuclear Information System (INIS)

    Stojanov, Dragan A.; Aracki-Trenkic, Aleksandra; Vojinovic, Slobodan; Ljubisavljevic, Srdjan; Benedeto-Stojanov, Daniela

    2016-01-01

    To evaluate correlation between cumulative dose of gadobutrol and signal intensity (SI) within dentate nucleus and globus pallidus on unenhanced T1-weighted images in patients with relapsing-remitting multiple sclerosis (RRMS). Dentate nucleus-to-pons and globus pallidus-to-thalamus SI ratios, and renal and liver functions, were evaluated after multiple intravenous administrations of 0.1 mmol/kg gadobutrol at 27, 96-98, and 168 weeks. We compared SI ratios based on the number of administrations, total amount of gadobutrol administered, and time between injections. Globus pallidus-to-thalamus (p = 0.025) and dentate nucleus-to-pons (p < 0.001) SI ratios increased after multiple gadobutrol administrations, correlated with the number of administrations (ρ = 0.263, p = 0.046, respectively) and depended on the length of administration (p = 0.017, p = 0.037, respectively). Patients receiving gadobutrol at 27 weeks showed the greatest increase in both SI ratios (p = 0.006; p = 0.014, respectively, versus 96-98 weeks). GGT increased at the end of the study (p = 0.004). In patients with RRMS, SI within the dentate nucleus and globus pallidus increased on unenhanced T1-weighted images after multiple gadobutrol injections. Administration of the same total amount of gadobutrol over a shorter period caused greater SI increase. (orig.)

  3. Increasing signal intensity within the dentate nucleus and globus pallidus on unenhanced T1W magnetic resonance images in patients with relapsing-remitting multiple sclerosis: correlation with cumulative dose of a macrocyclic gadolinium-based contrast agent, gadobutrol

    Energy Technology Data Exchange (ETDEWEB)

    Stojanov, Dragan A. [University of Nis, Faculty of Medicine, Nis (Serbia); Clinical Center Nis, Center for Radiology, Nis (Serbia); Aracki-Trenkic, Aleksandra [Clinical Center Nis, Center for Radiology, Nis (Serbia); Vojinovic, Slobodan; Ljubisavljevic, Srdjan [University of Nis, Faculty of Medicine, Nis (Serbia); Clinical Center Nis, Clinic for Neurology, Nis (Serbia); Benedeto-Stojanov, Daniela [University of Nis, Faculty of Medicine, Nis (Serbia)

    2016-03-15

    To evaluate correlation between cumulative dose of gadobutrol and signal intensity (SI) within dentate nucleus and globus pallidus on unenhanced T1-weighted images in patients with relapsing-remitting multiple sclerosis (RRMS). Dentate nucleus-to-pons and globus pallidus-to-thalamus SI ratios, and renal and liver functions, were evaluated after multiple intravenous administrations of 0.1 mmol/kg gadobutrol at 27, 96-98, and 168 weeks. We compared SI ratios based on the number of administrations, total amount of gadobutrol administered, and time between injections. Globus pallidus-to-thalamus (p = 0.025) and dentate nucleus-to-pons (p < 0.001) SI ratios increased after multiple gadobutrol administrations, correlated with the number of administrations (ρ = 0.263, p = 0.046, respectively) and depended on the length of administration (p = 0.017, p = 0.037, respectively). Patients receiving gadobutrol at 27 weeks showed the greatest increase in both SI ratios (p = 0.006; p = 0.014, respectively, versus 96-98 weeks). GGT increased at the end of the study (p = 0.004). In patients with RRMS, SI within the dentate nucleus and globus pallidus increased on unenhanced T1-weighted images after multiple gadobutrol injections. Administration of the same total amount of gadobutrol over a shorter period caused greater SI increase. (orig.)

  4. Residual signal auto-correlation to evaluate speech in Parkinson’s disease patients Auto-correlação do sinal residual para avaliação da fala em pacientes com doença de Parkinson

    Directory of Open Access Journals (Sweden)

    José Carlos Pereira

    2006-12-01

    Full Text Available OBJECTIVE: To evaluate the maximum residual signal auto-correlation also known as pitch amplitude (PA values in patients with Parkinson’s disease (PD patients. METHOD: The signals of 21 Parkinson’s patients were compared with 15 healthy individuals, divided according age and gender. RESULTS: Statistical difference was seen between groups for PA, 0.39 for controls and 0.25 for PD. Normal value threshold was set as 0.3; (pOBJETIVO: Avaliar autocorrelação do sinal residual também denominado como amplitude do pitch (PA em pacientes com doença de Parkinson (PD. MÉTODO: Os valores de PA, estratificados de acordo com idade e sexo, em 21 pacientes com doença de Parkinson foram analisados e comparados aos dados obtidos em 15 indivíduos sadios. RESULTADOS: Foi determinada diferença estatística para a PA entre os dois grupos (p0,3. Nos pacientes com PD 80,77% dos pacientes tinham a PA <0,3, enquanto que entre os controles somente 12,28% apresentavam valores abaixo de 0,3. O diagrama de dispersão para idade e sexo para os doentes com PD mostraram um p=0,001 e r=0,54. Não houve diferença em relação a sexo e idade entre os grupos. CONCLUSÃO: A significativa diferença da PA entre pacientes com PD e controles demonstra a especificidade da análise. Os resultados apontam para a necessidade de estudos controlados, prospectivos, para implementar o uso e indicações da determinação da amplitude do pitch na avaliação da fala em pacientes com doença de Parkinson.

  5. Accounting for the water-leaving radiance in the simultaneous retrieval of atmosphere and ocean properties from collocated polarimeters and lidar measurements: results for the SABOR campaign

    Science.gov (United States)

    Chowdhary, J.; Brian, C.; Stamnes, S.; Hostetler, C. A.; Cetinic, I.; Slade, W. H.; Hu, Y.

    2017-12-01

    Ocean spectra typically contribute less than 10% to top-of-atmosphere (TOA) radiance observations in the visible (VIS). The remaining 90% of TOA radiance originates from scattering in the atmosphere which needs to be removed (i.e. corrected) but varies substantially with the aerosol present at the time of observation. The traditional approach for atmospheric correction (AC), used for ocean color sensors such as SeaWiFS, MODIS, and VIIRS, estimates aerosol scattering properties from TOA radiance observations in the near-infrared/short-wave infrared (NIR/SWIR) where the ocean becomes dark. The aerosol model is subsequently used to compute the atmospheric scattering contribution to the TOA radiance in the VIS. The final step is to subtract this computed scattering contribution from the real (i.e. observed) TOA radiance. As an alternative to the traditional approach for AC, we retrieve the atmosphere (i.e., aerosol) and ocean (i.e., color) properties simultaneously from measurements in the VIS. To separate the information content for the atmosphere and ocean, we use lidar measurements and multi-angle polarization measurements. Lidar and polarimeter measurements are powerful tools to enhance the ocean product retrievals from conventional ocean color sensors, and are under consideration to accompany future generation ocean color sensors. Here, we present results of simultaneous atmosphere-ocean retrievals using collocated airborne lidar and polarimeter data that were acquired during the Ship-Aircraft Bio-Optical Research (SABOR) campaign. We discuss 2 hydrosol models (which differ in number of free parameters) that were used for these inversions. We then compare our ocean retrievals with measurements obtained from the accompanying cruise ship. Finally, we touch upon a next generation of hydrosol models that accommodates the unique sensitivity of ocean lidar profiles to plankton morphology.

  6. Imaging Polarimeter for a Sub-MeV Gamma-Ray All-sky Survey Using an Electron-tracking Compton Camera

    Energy Technology Data Exchange (ETDEWEB)

    Komura, S.; Takada, A.; Mizumura, Y.; Miyamoto, S.; Takemura, T.; Kishimoto, T.; Kubo, H.; Matsuoka, Y.; Mizumoto, T.; Nakamasu, Y.; Nakamura, K.; Oda, M.; Parker, J. D.; Sonoda, S.; Tanimori, T.; Tomono, D.; Yoshikawa, K. [Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502 (Japan); Kurosawa, S. [New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Miyagi, 980-8579 (Japan); Miuchi, K. [Department of Physics, Kobe University, Kobe, Hyogo, 658-8501 (Japan); Sawano, T., E-mail: komura@cr.scphys.kyoto-u.ac.jp [College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kanazawa, Ishikawa, 920-1192 (Japan)

    2017-04-10

    X-ray and gamma-ray polarimetry is a promising tool to study the geometry and the magnetic configuration of various celestial objects, such as binary black holes or gamma-ray bursts (GRBs). However, statistically significant polarizations have been detected in few of the brightest objects. Even though future polarimeters using X-ray telescopes are expected to observe weak persistent sources, there are no effective approaches to survey transient and serendipitous sources with a wide field of view (FoV). Here we present an electron-tracking Compton camera (ETCC) as a highly sensitive gamma-ray imaging polarimeter. The ETCC provides powerful background rejection and a high modulation factor over an FoV of up to 2 π sr thanks to its excellent imaging based on a well-defined point-spread function. Importantly, we demonstrated for the first time the stability of the modulation factor under realistic conditions of off-axis incidence and huge backgrounds using the SPring-8 polarized X-ray beam. The measured modulation factor of the ETCC was 0.65 ± 0.01 at 150 keV for an off-axis incidence with an oblique angle of 30° and was not degraded compared to the 0.58 ± 0.02 at 130 keV for on-axis incidence. These measured results are consistent with the simulation results. Consequently, we found that the satellite-ETCC proposed in Tanimori et al. would provide all-sky surveys of weak persistent sources of 13 mCrab with 10% polarization for a 10{sup 7} s exposure and over 20 GRBs down to a 6 × 10{sup −6} erg cm{sup −2} fluence and 10% polarization during a one-year observation.

  7. Expression profiles of carp IRF-3/-7 correlate with the up-regulation of RIG-I/MAVS/TRAF3/TBK1, four pivotal molecules in RIG-I signaling pathway.

    Science.gov (United States)

    Feng, Hong; Liu, Hong; Kong, Renqiu; Wang, Lu; Wang, Yaping; Hu, Wei; Guo, Qionglin

    2011-01-01

    The cytoplasmic helicase protein RIG-I (retinoic acid-inducible gene I) and downstream signaling molecules, MAVS (mitochondrial antiviral signaling protein), TRAF3 (TNF-receptor-associated factor 3) and TBK1 (TANK-binding kinase 1), have significant roles in the recognition of cytoplasmic 5'-triphosphate ssRNA and short dsRNA, and phosphorylation of IRF-3 (interferon regulatory factor 3) and IRF-7 which is responsible for the induction of type I interferons (IFN). In the present study, the full-length cDNAs of RIG-I, MAVS, TRAF3 and TBK1 were cloned and identified in common carp (Cyprinus carpio L.). The deduced protein of carp RIG-I is of 946 aa (amino acids), consisting of two CARDs (caspase-recruitment domain), a DEXDc (DExD/H box-containing domain), a HELICc (helicase superfamily c-terminal domain) and a RD (regulatory domain). Carp MAVS is of 585 aa, containing a CARD, a proline-rich region and a TM (transmembrane domain). Carp TRAF3 encodes a protein of 573 aa, including a RING (really interesting new gene), two TRAF-type zinc fingers, a coiled coil and a MATH-TRAF3 (meprin and TRAF homology) domain. Carp TBK1 is of 727 aa and contains a S_TKc domain (Serine/Threonine protein kinases, catalytic domain). Carp RIG-I, MAVS, TRAF3 and TBK1 mRNAs are ubiquitously expressed in all tissues examined. In response to SVCV infection, carp RIG-I and MAVS mRNAs were up-regulated at different levels in spleen, head kidney and intestine tissues at different time points. Similarly, both carp IRF-3 and IRF-7 mRNAs were significantly up-regulated in the detected tissues. Especially in intestine, the IRF-3 and IRF-7 mRNAs of carp increased and reached 25.3-fold (at 3 dpi) and 224.7-fold (at 5 dpi). Noteworthily, a significant growth of carp TRAF3 and TBK1 mRNA was also mainly found in intestine (7.0-fold and 11.3-fold at 5 dpi, respectively). These data implied that the expression profiles of IRF-3/-7 mRNAs in carp correlate with the up-regulation of RIG-I/MAVS/TRAF3/TBK, and

  8. Learning efficient correlated equilibria

    KAUST Repository

    Borowski, Holly P.

    2014-12-15

    The majority of distributed learning literature focuses on convergence to Nash equilibria. Correlated equilibria, on the other hand, can often characterize more efficient collective behavior than even the best Nash equilibrium. However, there are no existing distributed learning algorithms that converge to specific correlated equilibria. In this paper, we provide one such algorithm which guarantees that the agents\\' collective joint strategy will constitute an efficient correlated equilibrium with high probability. The key to attaining efficient correlated behavior through distributed learning involves incorporating a common random signal into the learning environment.

  9. Signal detection

    International Nuclear Information System (INIS)

    Tholomier, M.

    1985-01-01

    In a scanning electron microscope, whatever is the measured signal, the same set is found: incident beam, sample, signal detection, signal amplification. The resulting signal is used to control the spot luminosity with the observer cathodoscope. This is synchronized with the beam scanning on the sample; on the cathodoscope, the image in secondary electrons, backscattered electrons,... of the sample surface is reconstituted. The best compromise must be found between a register time low enough to remove eventual variations (under the incident beam) of the nature of the observed phenomenon, and a good spatial resolution of the image and a signal-to-noise ratio high enough. The noise is one of the basic limitations of the scanning electron microscope performance. The whose measurement line must be optimized to reduce it [fr

  10. Queen signaling in social wasps

    DEFF Research Database (Denmark)

    van Zweden, Jelle Stijn; Bonckaert, Wim; Wenseleers, Tom

    2014-01-01

    , thereby arguing against fast evolution of signals as a result of a queen-worker arms race ensuing from queen control. Lastly, levels of worker reproduction in these species correspond well with their average colony kin structures, as predicted by the queen signaling hypothesis but not the queen control...... hypothesis. Altogether, this correlative yet comprehensive analysis provides compelling evidence that honest signaling explains levels of reproductive division of labor in social wasps....

  11. Polarization Calibration of the Chromospheric Lyman-Alpha SpectroPolarimeter for a 0.1% Polarization Sensitivity in the VUV Range. Part II: In-Flight Calibration

    Science.gov (United States)

    Giono, G.; Ishikawa, R.; Narukage, N.; Kano, R.; Katsukawa, Y.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.; Winebarger, A.; Kobayashi, K.; Auchère, F.; Trujillo Bueno, J.; Tsuneta, S.; Shimizu, T.; Sakao, T.; Cirtain, J.; Champey, P.; Asensio Ramos, A.; Štěpán, J.; Belluzzi, L.; Manso Sainz, R.; De Pontieu, B.; Ichimoto, K.; Carlsson, M.; Casini, R.; Goto, M.

    2017-04-01

    The Chromospheric Lyman-Alpha SpectroPolarimeter is a sounding rocket instrument designed to measure for the first time the linear polarization of the hydrogen Lyman-{α} line (121.6 nm). The instrument was successfully launched on 3 September 2015 and observations were conducted at the solar disc center and close to the limb during the five-minutes flight. In this article, the disc center observations are used to provide an in-flight calibration of the instrument spurious polarization. The derived in-flight spurious polarization is consistent with the spurious polarization levels determined during the pre-flight calibration and a statistical analysis of the polarization fluctuations from solar origin is conducted to ensure a 0.014% precision on the spurious polarization. The combination of the pre-flight and the in-flight polarization calibrations provides a complete picture of the instrument response matrix, and a proper error transfer method is used to confirm the achieved polarization accuracy. As a result, the unprecedented 0.1% polarization accuracy of the instrument in the vacuum ultraviolet is ensured by the polarization calibration.

  12. Calibration of the Breit-Rabi Polarimeter for the PAX Spin-Filtering Experiment at COSY/Jülich and AD/CERN

    CERN Document Server

    Barschel, Colin

    2010-01-01

    The PAX(PolarizedAntiproton eXperiment) experiment is proposed to polarize a stored antiproton beam for use at the planned High Energy Storage Ring (HESR) of the FAIR facility at GSI (Darmstadt, Germany). The polarization build-up will be achieved by spin-filtering, i.e., by a repetitive passage of the antiproton beam through a polarized atomic hydrogen or deuterium gas target. The experimental setup requires a Polarized Internal gas Target (PIT) surrounded with silicon detectors. The PIT includes an Atomic Beam Source (ABS), the target cell and a Breit-Rabi Polarimeter (BRP). The first phase of the Spin-Filtering Studies for PAX covers the commissioning of the PIT components and themeasurement of an absolute calibration standard for the BRP at the COSY ring in Jülich. The spin-filtering with protons aim at confirming the results of the FILTEX experiment and determine the pp hadronic spin dependent cross sections at 50MeV.The second phase will be realized in the Antiproton Decelerator ring (AD) at CERN to po...

  13. An efficient, FPGA-based, cluster detection algorithm implementation for a strip detector readout system in a Time Projection Chamber polarimeter

    Science.gov (United States)

    Gregory, Kyle J.; Hill, Joanne E.; Black, J. Kevin; Baumgartner, Wayne H.; Jahoda, Keith

    2016-05-01

    A fundamental challenge in a spaceborne application of a gas-based Time Projection Chamber (TPC) for observation of X-ray polarization is handling the large amount of data collected. The TPC polarimeter described uses the APV-25 Application Specific Integrated Circuit (ASIC) to readout a strip detector. Two dimensional photo- electron track images are created with a time projection technique and used to determine the polarization of the incident X-rays. The detector produces a 128x30 pixel image per photon interaction with each pixel registering 12 bits of collected charge. This creates challenging requirements for data storage and downlink bandwidth with only a modest incidence of photons and can have a significant impact on the overall mission cost. An approach is described for locating and isolating the photoelectron track within the detector image, yielding a much smaller data product, typically between 8x8 pixels and 20x20 pixels. This approach is implemented using a Microsemi RT-ProASIC3-3000 Field-Programmable Gate Array (FPGA), clocked at 20 MHz and utilizing 10.7k logic gates (14% of FPGA), 20 Block RAMs (17% of FPGA), and no external RAM. Results will be presented, demonstrating successful photoelectron track cluster detection with minimal impact to detector dead-time.

  14. Phosphoinositide signaling.

    Science.gov (United States)

    Boss, Wendy F; Im, Yang Ju

    2012-01-01

    "All things flow and change…even in the stillest matter there is unseen flux and movement." Attributed to Heraclitus (530-470 BC), from The Story of Philosophy by Will Durant. Heraclitus, a Greek philosopher, was thinking on a much larger scale than molecular signaling; however, his visionary comments are an important reminder for those studying signaling today. Even in unstimulated cells, signaling pathways are in constant metabolic flux and provide basal signals that travel throughout the organism. In addition, negatively charged phospholipids, such as the polyphosphorylated inositol phospholipids, provide a circuit board of on/off switches for attracting or repelling proteins that define the membranes of the cell. This template of charged phospholipids is sensitive to discrete changes and metabolic fluxes-e.g., in pH and cations-which contribute to the oscillating signals in the cell. The inherent complexities of a constantly fluctuating system make understanding how plants integrate and process signals challenging. In this review we discuss one aspect of lipid signaling: the inositol family of negatively charged phospholipids and their functions as molecular sensors and regulators of metabolic flux in plants.

  15. Understanding volatility correlation behavior with a magnitude cross-correlation function

    Science.gov (United States)

    Jun, Woo Cheol; Oh, Gabjin; Kim, Seunghwan

    2006-06-01

    We propose an approach for analyzing the basic relation between correlation properties of the original signal and its magnitude fluctuations by decomposing the original signal into its positive and negative fluctuation components. We use this relation to understand the following phenomenon found in many naturally occurring time series: the magnitude of the signal exhibits long-range correlation, whereas the original signal is short-range correlated. The applications of our approach to heart rate variability signals and high-frequency foreign exchange rates reveal that the difference between the correlation properties of the original signal and its magnitude fluctuations is induced by the time organization structure of the correlation function between the magnitude fluctuations of positive and negative components. We show that this correlation function can be described well by a stretched-exponential function and is related to the nonlinearity and the multifractal structure of the signals.

  16. Scanning image correlation spectroscopy.

    Science.gov (United States)

    Digman, Michelle A; Gratton, Enrico

    2012-05-01

    Molecular interactions are at the origin of life. How molecules get at different locations in the cell and how they locate their partners is a major and partially unresolved question in biology that is paramount to signaling. Spatio-temporal correlations of fluctuating fluorescently tagged molecules reveal how they move, interact, and bind in the different cellular compartments. Methods based on fluctuations represent a remarkable technical advancement in biological imaging. Here we discuss image analysis methods based on spatial and temporal correlation of fluctuations, raster image correlation spectroscopy, number and brightness, and spatial cross-correlations that give us information about how individual molecules move in cells and interact with partners at the single molecule level. These methods can be implemented with a standard laser scanning microscope and produce a cellular level spatio-temporal map of molecular interactions. Copyright © 2012 WILEY Periodicals, Inc.

  17. Signal integrity characterization techniques

    CERN Document Server

    Bogatin, Eric

    2009-01-01

    "Signal Integrity Characterization Techniques" addresses the gap between traditional digital and microwave curricula all while focusing on a practical and intuitive understanding of signal integrity effects within the data transmission channel. High-speed interconnects such as connectors, PCBs, cables, IC packages, and backplanes are critical elements of differential channels that must be designed using today's most powerful analysis and characterization tools.Both measurements and simulation must be done on the device under test, and both activities must yield data that correlates with each other. Most of this book focuses on real-world applications of signal integrity measurements - from backplane for design challenges to error correction techniques to jitter measurement technologies. The authors' approach wisely addresses some of these new high-speed technologies, and it also provides valuable insight into its future direction and will teach the reader valuable lessons on the industry.

  18. Score Correlation

    Czech Academy of Sciences Publication Activity Database

    Fabián, Zdeněk

    2010-01-01

    Roč. 20, č. 6 (2010), s. 793-798 ISSN 1210-0552 R&D Projects: GA ČR GA205/09/1079 Institutional research plan: CEZ:AV0Z10300504 Keywords : score function * correlation * rank correlation coefficient * heavy tails Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.511, year: 2010

  19. Signal Processing

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Signal processing techniques, extensively used nowadays to maximize the performance of audio and video equipment, have been a key part in the design of hardware and software for high energy physics detectors since pioneering applications in the UA1 experiment at CERN in 1979

  20. Quantum mechanics and the theories of local hidden variables: an experimental test by measuring the spin correlation function in p-p scattering

    International Nuclear Information System (INIS)

    Lamehi-Rachti, Mohammad.

    1976-01-01

    The Einstein-Podolsky-Rosen paradox is briefly exposed with the Bell theorem on hidden variables and the locality principle. The conditions for an ideal experiment are discussed and the results from γ-γ correlation experiments are given. The principle of an experimental measurement of the spin correlation function predicted by the quantum mechanics theory is derived, new hypotheses to be introduced are discussed. The formula giving the dependence of the counting asymmetry on the spin correlation function, polarimeter analyzing power, and geometric correlation is developed. The principle of a Monte Carlo calculation is also exposed. The experimental device is described with the methods for measuring the subsidiary quantities and experimental results are analyzed [fr

  1. Linearity Analysis and Efficiency Testing of The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) Science Cameras for Flight

    Science.gov (United States)

    Walker, S. C.; Rachmeler, L.; Winebarger, A. R.; Champey, P. R.; Bethge, C.

    2017-12-01

    To unveil the complexity of the solar atmosphere, measurement of the magnetic field in the upper chromosphere and transition region is fundamentally important, as this is where the forces transition from plasma to magnetic field dominated. Measurements of the field are also needed to shed light on the energy transport from the lower atmospheric regions to the corona beyond. Such an advance in heliospheric knowledge became possible with the first flight of the international solar sounding rocket mission, CLASP. For the first time, linear polarization was measured in H Lyman-Alpha at 121.60 nm in September 2015. For linear polarization measurements in this line, high sensitivity is required due to the relatively weak polarization signal compared to the intensity. To achieve this high sensitivity, a low-noise sensor is required with good knowledge of its characterization, including linearity. This work presents further refinement of the linearity characterization of the cameras flown in 2015. We compared the current from a photodiode in the light path to the digital response of the detectors. Pre-flight CCD linearity measurements were taken for all three flight cameras and calculations of the linear fits and residuals were performed. However, the previous calculations included a smearing pattern and a digital saturation region on the detectors which were not properly taken into account. The calculations have been adjusted and were repeated for manually chosen sub-regions on the detectors that were found not to be affected. We present a brief overview of the instrument, the calibration data and procedures, and a comparison of the old and new linearity results. The CLASP cameras will be reused for the successor mission, CLASP2, which will measure the Mg II h & k lines between 279.45 nm and 280.35 nm. The new approach will help to better prepare for and to improve the camera characterization for CLASP2.

  2. Linearity Analysis and Efficiency Testing of The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) Science Cameras for Flight

    Science.gov (United States)

    Walker, Salma C.; Rachmeler, Laurel; Winebarger, Amy; Champey, Patrick; Bethge, Christian

    2018-01-01

    To unveil the complexity of the solar atmosphere, measurement of the magnetic field in the upper chromosphere and transition region is fundamentally important, as this is where the forces transition from plasma to magnetic field dominated. Measurements of the field are also needed to elucidate the energy transport from the lower atmospheric regions to the corona beyond. Such an advance in heliospheric knowledge became possible with the first flight of the international solar sounding rocket mission, CLASP. For the first time, linear polarization was measured in Hydrogen Lyman-Alpha at 121.60 nm in September 2015. For linear polarization measurements in this emission line, high sensitivity is required due to the relatively weak polarization signal compared to the intensity. To achieve this high sensitivity, a low-noise sensor is required with good knowledge of its characterization, including linearity. This work presents further refinement of the linearity characterization of the cameras flown in 2015. We compared the current from a photodiode in the light path to the digital response of the detectors. Pre-flight CCD linearity measurements were taken for all three flight cameras and calculations of the linear fits and residuals were performed. However, the previous calculations included a smearing pattern and a digital saturation region on the detectors which were not properly taken into account. The calculations have been adjusted and were repeated for manually chosen sub-regions on the detectors that were found not to be affected. We present a brief overview of the instrument, the calibration data and procedures, and a comparison of the old and new linearity results. The CLASP cameras will be reused for the successor mission, CLASP2, which will measure the Magnesium II h & k emission lines between 279.45 nm and 280.35 nm. The new approach will help to better prepare for and to improve the camera characterization for CLASP2.

  3. Study of the polarization dependence of the photoelectric effect in the soft X-ray band - A focal plane photoelectric stellar X-ray polarimeter for the Spectrum-X-Gamma mission

    International Nuclear Information System (INIS)

    Heckler, A.; Blaer, A.; Kaaret, P.; Novick, R.

    1989-01-01

    An experimental study of the polarization dependence of the photoelectric effect in cesium iodide in the soft X-ray band was started (Heckler et al., 1989). At a grazing angle of 10 degrees and a photon energy of 2.6 keV, it is found that the photoelectric yield from a thin layer of evaporated cesium iodide varies by 12.4 percent as the polarization vector of the incident X-ray beam is rotated about the line-of-sight. The rotation angle corresponding to the maximum photoyield is displaced by 16 degrees from the normal to the photocathode. This modulation and phase shift are in good agreement with the results recently reported by Fraser, et al. (1989) It is shown that a focal plane stellar X-ray polarimeter based on this photoelectric effect will be substantially more efficient than convential X-ray polarimeters such as those based on either Bragg reflection or scattering from low atomic number targets. 7 refs

  4. Prosocial Signalling

    DEFF Research Database (Denmark)

    Kahsay, Goytom Abraha

    signalling can cause reverse price reactions resembling the crowding-out of pre-existing motives for prosocial behavior seen in situations of volunteering and charitable giving. Using a unique combination of questionnaire and purchase panel data, it presents evidence of such reputation-driven reverse price...... reactions in the Danish market for organic milk. The second paper proposes a self-image model to account consumers’ behaviour under PWYW. It finds that when a good’s fixed price is lower than an exogenously given threshold fair value, PWYW can lead to a lower utility, which may lead to lower purchase rate...

  5. Ultrasound imaging using coded signals

    DEFF Research Database (Denmark)

    Misaridis, Athanasios

    coded excitation can be used for increasing the frame rate. The work includes both simulated results using Field II, and experimental results based on measurements on phantoms as well as clinical images. Initially a mathematical foundation of signal modulation is given. Pulse compression based...... is described. Application of coded excitation in array imaging is evaluated through simulations in Field II. The low degree of the orthogonality among coded signals for ultrasound systems is first discussed, and the effect of mismatched filtering in the cross-correlation properties of the signals is evaluated...... emissions. Finally, a novel coding technique which uses pulse train excitation is presented....

  6. Signal focusing through active transport

    Science.gov (United States)

    Godec, Aljaž; Metzler, Ralf

    2015-07-01

    The accuracy of molecular signaling in biological cells and novel diagnostic devices is ultimately limited by the counting noise floor imposed by the thermal diffusion. Motivated by the fact that messenger RNA and vesicle-engulfed signaling molecules transiently bind to molecular motors and are actively transported in biological cells, we show here that the random active delivery of signaling particles to within a typical diffusion distance to the receptor generically reduces the correlation time of the counting noise. Considering a variety of signaling particle sizes from mRNA to vesicles and cell sizes from prokaryotic to eukaryotic cells, we show that the conditions for active focusing—faster and more precise signaling—are indeed compatible with observations in living cells. Our results improve the understanding of molecular cellular signaling and novel diagnostic devices.

  7. Compressive sensing and entropy in seismic signals

    Science.gov (United States)

    Marinho, Eberton S.; Rocha, Tiago C.; Corso, Gilberto; Lucena, Liacir S.

    2017-09-01

    This work analyzes the correlation between the seismic signal entropy and the Compressive Sensing (CS) recovery index. The recovery index measures the quality of a signal reconstructed by the CS method. We analyze the performance of two CS algorithms: the ℓ1-MAGIC and the Fast Bayesian Compressive Sensing (BCS). We have observed a negative correlation between the performance of CS and seismic signal entropy. Signals with low entropy have small recovery index in their reconstruction by CS. The rationale behind our finding is: a sparse signal is easy to recover by CS and, besides, a sparse signal has low entropy. In addition, ℓ1-MAGIC shows a more significant correlation between entropy and CS performance than Fast BCS.

  8. Erratum: Efficiency of the cross-correlation statistic for gravitational wave stochastic background signals with non-Gaussian noise and heterogeneous detector sensitivities [Phys. Rev. D 92, 104025 (2015)

    Science.gov (United States)

    Martellini, Lionel; Regimbau, Tania

    2018-02-01

    We present an erratum with respect to the paper. The results presented are based on an incorrect expression for the standard detection statistic, which does not include the correction to the cross-correlation term that is required when the detector sensitivities are assumed to be known. We are grateful to Joe Romano for pointing out the problem and providing helpful feedback in the revision efforts.

  9. Interleukin-1 (IL-1) signaling in intestinal stromal cells controls KC/ CXCL1 secretion, which correlates with recruitment of IL-22- secreting neutrophils at early stages of Citrobacter rodentium infection.

    Science.gov (United States)

    Lee, Yong-Soo; Yang, Hyungjun; Yang, Jin-Young; Kim, Yeji; Lee, Su-Hyun; Kim, Ji Heui; Jang, Yong Ju; Vallance, Bruce A; Kweon, Mi-Na

    2015-08-01

    Attaching and effacing pathogens, including enterohemorrhagic Escherichia coli in humans and Citrobacter rodentium in mice, raise serious public health concerns. Here we demonstrate that interleukin-1 receptor (IL-1R) signaling is indispensable for protection against C. rodentium infection in mice. Four days after infection with C. rodentium, there were significantly fewer neutrophils (CD11b+ Ly6C+ Ly6G+) in the colons of IL-1R−/− mice than in wild-type mice. Levels of mRNA and protein of KC/CXCL1 were also significantly reduced in colon homogenates of infected IL-1R−/− mice relative to wild-type mice. Of note, infiltrated CD11b+ Ly6C+ Ly6G+ neutrophils were the main source of IL-22 secretion after C. rodentium infection. Interestingly, intestinal stromal cells isolated from IL-1R−/− mice secreted lower levels of KC/CXCL1 than stromal cells from wild-type mice during C. rodentium infection. Similar effects were found when mouse intestinal stromal cells and human nasal polyp stromal cells were treated with IL-1R antagonists (i.e., anakinra) in vitro. These results suggest that IL-1 signaling plays a pivotal role in activating mucosal stromal cells to secrete KC/CXCL1, which is essential for infiltration of IL-22-secreting neutrophils upon bacterial infection.

  10. Co-expression of ILT4/HLA-G in human non-small cell lung cancer correlates with poor prognosis and ILT4-HLA-G interaction activates ERK signaling.

    Science.gov (United States)

    Zhang, Yanwen; Zhao, Jianqiang; Qiu, Lijun; Zhang, Pei; Li, Juan; Yang, Dong; Wei, Xiaojuan; Han, Yali; Nie, Siyue; Sun, Yuping

    2016-08-01

    Non-small cell lung cancer (NSCLC) is the most common malignant tumor in the world, of which prognosis is generally poor due to insufficient mechanistic understanding. To explore the molecular pathogenesis of NSCLC, the co-expression of immunoglobulin-like transcript 4 (ILT4) and its ligand human leukocyte antigen G (HLA-G) in NSCLC tissues and cells were investigated. Here, we detected the expression of ILT4 and HLA-G in 81 tumor specimens from primary NSCLC patients, and we found that co-expression of ILT4/HLA-G was significantly associated with regional lymph node involvement, advanced stages, and the overall survival of patients. In NSCLC cell lines, HLA-G expression increased/decreased accordingly when ILT4 was up-/down-regulated, and ILT4 expression increased in a concentration-dependent manner via the stimulation of HLA-G fusion protein. Interestingly, HLA-G fusion protein could also up-regulate the phospho-ERK1/2 expression, which means the activation of extracellular signal-regulated kinase (ERK) signaling. All in all, our results indicate that the ILT4-HLA-G interaction might play an important role in NSCLC progression. Identification of ILT4 and HLA-G expression may provide an indicator to predict prognosis and guide prevention and treatment of NSCLC.

  11. Why Waveform Correlation Sometimes Fails

    Science.gov (United States)

    Carmichael, J.

    2015-12-01

    Waveform correlation detectors used in explosion monitoring scan noisy geophysical data to test two competing hypotheses: either (1) an amplitude-scaled version of a template waveform is present, or, (2) no signal is present at all. In reality, geophysical wavefields that are monitored for explosion signatures include waveforms produced by non-target sources that are partially correlated with the waveform template. Such signals can falsely trigger correlation detectors, particularly at low thresholds required to monitor for smaller target explosions. This challenge is particularly formidable when monitoring known test sites for seismic disturbances, since uncatalogued natural seismicity is (generally) more prevalent at lower magnitudes, and could be mistaken for small explosions. To address these challenges, we identify real examples in which correlation detectors targeting explosions falsely trigger on both site-proximal earthquakes (Figure 1, below) and microseismic "noise". Motivated by these examples, we quantify performance loss when applying these detectors, and re-evaluate the correlation-detector's hypothesis test. We thereby derive new detectors from more general hypotheses that admit unknown background seismicity, and apply these to real data. From our treatment, we derive "rules of thumb'' for proper template and threshold selection in heavily cluttered signal environments. Last, we answer the question "what is the probability of falsely detecting an earthquake collocated at a test site?", using correlation detectors that include explosion-triggered templates. Figure Top: An eight-channel data stream (black) recorded from an earthquake near a mine. Red markers indicate a detection. Middle: The correlation statistic computed by scanning the template against the data stream at top. The red line indicates the threshold for event declaration, determined by a false-alarm on noise probability constraint, as computed from the signal-absent distribution using

  12. Signals, systems, transforms, and digital signal processing with Matlab

    CERN Document Server

    Corinthios, Michael

    2009-01-01

    Continuous-Time and Discrete-Time Signals and SystemsIntroductionContinuous-Time SignalsPeriodic FunctionsUnit Step FunctionGraphical Representation of FunctionsEven and Odd Parts of a FunctionDirac-Delta ImpulseBasic Properties of the Dirac-Delta ImpulseOther Important Properties of the ImpulseContinuous-Time SystemsCausality, StabilityExamples of Electrical Continuous-Time SystemsMechanical SystemsTransfer Function and Frequency ResponseConvolution and CorrelationA Right-Sided and a Left-Sided FunctionConvolution with an Impulse and Its DerivativesAdditional Convolution PropertiesCorrelation FunctionProperties of the Correlation FunctionGraphical InterpretationCorrelation of Periodic FunctionsAverage, Energy and Power of Continuous-Time SignalsDiscrete-Time SignalsPeriodicityDifference EquationsEven/Odd DecompositionAverage Value, Energy and Power SequencesCausality, StabilityProblemsAnswers to Selected ProblemsFourier Series ExpansionTrigonometric Fourier SeriesExponential Fourier SeriesExponential versus ...

  13. Inability of NS1 protein from an H5N1 influenza virus to activate PI3K/Akt signaling pathway correlates to the enhanced virus replication upon PI3K inhibition

    Directory of Open Access Journals (Sweden)

    Li Weizhong

    2012-04-01

    Full Text Available Abstract Background Phosphatidylinositol 3-kinase (PI3K/Akt signaling pathway, activated during influenza A virus infection, can promote viral replication via multiple mechanisms. Direct binding of NS1 protein to p85β subunit of PI3K is required for activation of PI3K/Akt signaling. Binding and subsequent activation of PI3K is believed to be a conserved character of influenza A virus NS1 protein. Sequence variation of NS1 proteins in different influenza A viruses led us to investigate possible deviation from the conservativeness. Results In the present study, NS1 proteins from four different influenza A virus subtypes/strains were tested for their ability to bind p85β subunit of PI3K and to activate PI3K/Akt. All NS1 proteins efficiently bound to p85β and activated PI3K/Akt, with the exception of NS1 protein from an H5N1 virus (A/Chicken/Guangdong/1/05, abbreviated as GD05, which bound to p85β but failed to activate PI3K/Akt, implying that as-yet-unidentified domain(s in NS1 may alternatively mediate the activation of PI3K. Moreover, PI3K inhibitor, LY294002, did not suppress but significantly increased the replication of GD05 virus. Conclusions Our study indicates that activation of PI3K/Akt by NS1 protein is not highly conserved among influenza A viruses and inhibition of the PI3K/Akt pathway as an anti-influenza strategy may not work for all influenza A viruses.

  14. Correlation spectrometer

    Science.gov (United States)

    Sinclair, Michael B [Albuquerque, NM; Pfeifer, Kent B [Los Lunas, NM; Flemming, Jeb H [Albuquerque, NM; Jones, Gary D [Tijeras, NM; Tigges, Chris P [Albuquerque, NM

    2010-04-13

    A correlation spectrometer can detect a large number of gaseous compounds, or chemical species, with a species-specific mask wheel. In this mode, the spectrometer is optimized for the direct measurement of individual target compounds. Additionally, the spectrometer can measure the transmission spectrum from a given sample of gas. In this mode, infrared light is passed through a gas sample and the infrared transmission signature of the gasses present is recorded and measured using Hadamard encoding techniques. The spectrometer can detect the transmission or emission spectra in any system where multiple species are present in a generally known volume.

  15. Intracellular signal modulation by nanomaterials.

    Science.gov (United States)

    Hussain, Salik; Garantziotis, Stavros; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Baeza-Squiban, Armelle; Boland, Sonja

    2014-01-01

    A thorough understanding of the interactions of nanomaterials with biological systems and the resulting activation of signal transduction pathways is essential for the development of safe and consumer friendly nanotechnology. Here we present an overview of signaling pathways induced by nanomaterial exposures and describe the possible correlation of their physicochemical characteristics with biological outcomes. In addition to the hierarchical oxidative stress model and a review of the intrinsic and cell-mediated mechanisms of reactive oxygen species (ROS) generating capacities of nanomaterials, we also discuss other oxidative stress dependent and independent cellular signaling pathways. Induction of the inflammasome, calcium signaling, and endoplasmic reticulum stress are reviewed. Furthermore, the uptake mechanisms can be of crucial importance for the cytotoxicity of nanomaterials and membrane-dependent signaling pathways have also been shown to be responsible for cellular effects of nanomaterials. Epigenetic regulation by nanomaterials, effects of nanoparticle-protein interactions on cell signaling pathways, and the induction of various cell death modalities by nanomaterials are described. We describe the common trigger mechanisms shared by various nanomaterials to induce cell death pathways and describe the interplay of different modalities in orchestrating the final outcome after nanomaterial exposures. A better understanding of signal modulations induced by nanomaterials is not only essential for the synthesis and design of safer nanomaterials but will also help to discover potential nanomedical applications of these materials. Several biomedical applications based on the different signaling pathways induced by nanomaterials are already proposed and will certainly gain a great deal of attraction in the near future.

  16. On statistical significance of signal

    International Nuclear Information System (INIS)

    Zhu Yongsheng

    2006-01-01

    A definition for the statistical significance of a signal in an experiment is proposed by establishing a correlation between the observed p-value and the normal distribution integral probability, which is suitable for both counting experiment and continuous test statistics. The explicit expressions to calculate the statistical significance for both cases are given. (author)

  17. Correlation between Focal Nodular Low Signal Changes in Hoffa’s Fat Pad Adjacent to Anterior Femoral Cartilage and Focal Cartilage Defect Underlying This Region and Its Possible Implication

    Directory of Open Access Journals (Sweden)

    Chermaine Deepa Antony

    2016-01-01

    Full Text Available Purpose. This study investigates the association between focal nodular mass with low signal in Hoffa’s fat pad adjacent to anterior femoral cartilage of the knee (FNMHF and focal cartilage abnormality in this region. Method. The magnetic resonance fast imaging employing steady-state acquisition sequence (MR FIESTA sagittal and axial images of the B1 and C1 region (described later of 148 patients were independently evaluated by two reviewers and categorized into four categories: normal, FNMHF with underlying focal cartilage abnormality, FNMHF with normal cartilage, and cartilage abnormality with no FNMHF. Results. There was a significant association (p=0.00 between FNMHF and immediate adjacent focal cartilage abnormality with high interobserver agreement. The absence of focal nodular lesions next to the anterior femoral cartilage has a very high negative predictive value for chondral injury (97.8%. Synovial biopsy of focal nodular lesion done during arthroscopy revealed some fibrocollagenous tissue and no inflammatory cells. Conclusion. We postulate that the FNMHF adjacent to the cartilage defects is a form of normal healing response to the cartilage damage. One patient with FHMHF and underlying cartilage abnormality was rescanned six months later. In this patient, the FNMHF disappeared and normal cartilage was observed in the adjacent region which may support this theory.

  18. Use of sparker signal to classify seafloor sediment

    Digital Repository Service at National Institute of Oceanography (India)

    Pathak, D.; Ranade, G.; Sudhakar, T.

    During the cruise 190 of R.V. Gaveshani, the sparker signal was recorded in the analog form on audio cassettes. This signal has been digitized and a statistical computation, viz. the normalized cross-correlation function between successive echoes...

  19. Oxygen-glucose deprivation enhancement of cell death/apoptosis in PC12 cells and hippocampal neurons correlates with changes in neuronal excitatory amino acid neurotransmitter signaling and potassium currents.

    Science.gov (United States)

    Wang, Yu-Xiang; Zhang, Feng; Ma, Xue-Ling; He, Cong-Cong; Tian, Kun; Wang, Hong-Gang; An, Di; Heng, Bin; Xie, Lai-Hua; Liu, Yan-Qiang

    2016-05-25

    Neuronal death is a pathophysiological process that is often caused by hypoxia/ischemia. However, the causes of hypoxia/ischemia-induced neuronal death are debated, and additional experimental data are needed to resolve this debate. In the present study, we applied oxygen-glucose deprivation (OGD) to PC12 cells and hippocampal neurons to establish a hypoxia/ischemia model. We evaluated the effects of OGD on cell death/apoptosis and on the levels of two excitatory amino acid neurotransmitters, aspartic acid and glutamic acid, in both hippocampal neurons and the medium used to culture the hippocampal neurons. We also evaluated GluR2 expression in hippocampal neurons as well as the effects of OGD on whole-cell potassium currents in PC12 cells and hippocampal neurons. Our experimental results showed that OGD significantly decreased cell viability and markedly enhanced apoptosis in PC12 cells and hippocampal neurons. OGD treatment for 3 h increased the levels of Asp and Glu in the medium used to culture hippocampal neurons, but decreased both the levels of Asp and Glu and GluR2 expression in hippocampal neurons. Furthermore, OGD altered the electrophysiological properties of voltage-dependent potassium channels in PC12 cells and hippocampal neurons in different ways; OGD decreased the voltage-dependent potassium current in PC12 cells, but increased this current in hippocampal neurons. On the basis of these results, we concluded that OGD enhanced neuronal cell death/apoptosis in addition to altering neuronal excitatory amino acid neurotransmitter signaling and whole-cell voltage-dependent potassium currents.

  20. Invited Article: A novel calibration method for the JET real-time far infrared polarimeter and integration of polarimetry-based line-integrated density measurements for machine protection of a fusion plant.

    Science.gov (United States)

    Boboc, A; Bieg, B; Felton, R; Dalley, S; Kravtsov, Yu

    2015-09-01

    In this paper, we present the work in the implementation of a new calibration for the JET real-time polarimeter based on the complex amplitude ratio technique and a new self-validation mechanism of data. This allowed easy integration of the polarimetry measurements into the JET plasma density control (gas feedback control) and as well as machine protection systems (neutral beam injection heating safety interlocks). The new addition was used successfully during 2014 JET Campaign and is envisaged that will operate routinely from 2015 campaign onwards in any plasma condition (including ITER relevant scenarios). This mode of operation elevated the importance of the polarimetry as a diagnostic tool in the view of future fusion experiments.

  1. Invited Article: A novel calibration method for the JET real-time far infrared polarimeter and integration of polarimetry-based line-integrated density measurements for machine protection of a fusion plant

    International Nuclear Information System (INIS)

    Boboc, A.; Felton, R.; Dalley, S.; Bieg, B.; Kravtsov, Yu.

    2015-01-01

    In this paper, we present the work in the implementation of a new calibration for the JET real-time polarimeter based on the complex amplitude ratio technique and a new self-validation mechanism of data. This allowed easy integration of the polarimetry measurements into the JET plasma density control (gas feedback control) and as well as machine protection systems (neutral beam injection heating safety interlocks). The new addition was used successfully during 2014 JET Campaign and is envisaged that will operate routinely from 2015 campaign onwards in any plasma condition (including ITER relevant scenarios). This mode of operation elevated the importance of the polarimetry as a diagnostic tool in the view of future fusion experiments

  2. [The correlation between the concentrations of VEGF and PEDF and Ca2+-PKC signaling pathways in human retinal pigment epithelial cells cultured in vitro after exposuring to blue light].

    Science.gov (United States)

    Wang, Limin; Cai, Shanjun; Wu, Zhipeng; Gong, Xin; Lyu, Jianping; Su, Gang; Wang, Lili

    2015-11-01

    To investigate the concentrations of vascular endothelial growth factor (VEGF), pigment epithelium-derived factor (PEDF), inositol triphosphate (IP3) and diacylglycerol (DAG) in human retinal pigment epithelium (RPE) cells after exposuring to blue light, and to explore the relationship with Ca2+-PKC signaling pathways, to evaluate the role of Ca2+-PKC signaling pathways of blue-light irradiation induced apoptosis in RPE cells. The fourth generation human RPE cells in vitro were exposured to blue light (2000±500 lux) for 6 hours, 24 hours prolongation of post-exposure culture. The concentrations of VEGF, PEDF, IP3 and DAG were assayed by enzyme linked immunosorbent assay (ELISA). Cells were randomly divided into 6 groups, group A (control), group B (exposure to blue light), group C (exposure to blue light+PMA), group D (exposure to blue light+Calphostin C), group E (exposure to blue light+Nifedipine), group F (exposure to blue light+Calphostin C+Nifedipine). Flow cytometry was used to detect the apoptosis rate of human RPE cells in A, B and F group. Comparing with group A (584.38±10.66), the concentration of VEGF in group B (700.70±5.88), group C (698.21±6.66) and group E (648.30±4.91) was higher, the difference was statistically significant (P=0.002, 0.002, 0.016). Comparing with group B (700.70±5.88), the concentration of VEGF in Group D (623.87±3.12) and E (648.30±4.91) was lower (P=0.001, 0.002). Comparing with group A (75.96±1.70), the concentration of PEDF in Group B (71.82±1.67) and C (72.43±0.58) was lower (P=0.004, 0.011), but the concentration of PEDF in Group D (86.31±1.35) and E (93.72±1.24) was higher (P=0.000, 0.000). Comparing with group B (71.82±1.67), the concentration of PEDF in Group D (86.31±1.35) and E (93.72±1.24) was higher (P=0.000, 0.000). Comparing with group A (7.70±0.29), the ratio of VEGF to PEDF in Group B (9.85±0.34) and Croup C (9.64±0.02) was higher (P=0.008, 0.027) Comparing with group B, The ratio of VEGF to PEDF

  3. A new polarimeter scheme based on solid state semiconductors Un nuevo esquema para polarímetros basado en semiconductor de estado sólido

    Directory of Open Access Journals (Sweden)

    Heiner Castro Gutierrez

    2012-12-01

    Full Text Available A new kind of polarimeter scheme is suggested using solid state semiconductors. The new approach is based on the modulation over the intensities of the diffracted beams through a two-dimensional chiral grating, reported recently. It will be demonstrated that at least four intensity measurements of no equivalent diffracted beams are needed in order to estimate the polarization state of the incident beam. The incident beam azimuth was varied by routing a linear polarizer lens mounting in a stepped motor. The intensities of four diffracted beams were measured using a screen, a CCD camera and some algorithms running in a computer. The LabVIEW development environment software was used for controlling the hardware and for presenting the results. MATLAB© was used for calculating the intensities of the diffracted beams and computing the azimuth of the incident beam. Although both the azimuth and ellipticity should be estimated, the experiments show that only the azimuth estimation yields accurate results. The ellipticity cannot be estimated with precision. The error on the azimuth estimation depends on the variation in the power of the incident beam. It was found that the azimuth estimation is accurate between [0,140 and (150,180] degrees. The cause of huge errors in the azimuth found between 140 and 150 degrees are kept unknown.Un nuevo esquema de polarímetro es sugerido usando semiconductores de estado sólido. La nueva aproximación está basada en la modulación sobre las intensidades de los rayos difractados a través de una rejilla quiral de dos dimensiones reportado recientemente. Será demostrado que al menos cuatro mediciones de intensidades de rayos difractados no equivalentes son necesarios para estimar el estado de polarización del rayo incidente. El azimut del rayo incidente es variado, rotando un lente polarizador lineal montado en un motor paso a paso. La intensidad de cuatro rayos difractados es medida por medio de una peque

  4. Low-energy deuteron polarimeter

    NARCIS (Netherlands)

    Bellos, A; Kalantar-Nayestanaki, N; Kremers, HR; Messchendorp, JG; KalantarNayestanaki, N; Timmermans, RGE; Bakker, BLG

    2005-01-01

    Polarized beams or targets are used in nuclear few-body experiments to extract observables such as analyzing powers and spin-transfer coefficients. These measured observables can be compared to theoretical models to study, for example, three-body interactions, or, the properties of the spin-orbit

  5. Digital Signal Processor For GPS Receivers

    Science.gov (United States)

    Thomas, J. B.; Meehan, T. K.; Srinivasan, J. M.

    1989-01-01

    Three innovative components combined to produce all-digital signal processor with superior characteristics: outstanding accuracy, high-dynamics tracking, versatile integration times, lower loss-of-lock signal strengths, and infrequent cycle slips. Three components are digital chip advancer, digital carrier downconverter and code correlator, and digital tracking processor. All-digital signal processor intended for use in receivers of Global Positioning System (GPS) for geodesy, geodynamics, high-dynamics tracking, and ionospheric calibration.

  6. Variable angle correlation spectroscopy

    International Nuclear Information System (INIS)

    Lee, Y.K.; Lawrence Berkeley Lab., CA

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13 C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system

  7. Variable angle correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Kyo [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

  8. Signal recovery in imaging photoplethysmography

    International Nuclear Information System (INIS)

    Holton, Benjamin D; Mannapperuma, Kavan; Lesniewski, Peter J; Thomas, John C

    2013-01-01

    Imaging photoplethysmography is an emerging technique for the extraction of biometric information from people using video recordings. The focus is on extracting the cardiac heart rate of the subject by analysing the luminance of the colour video signal and identifying periodic components. Advanced signal processing is needed to recover the information required. In this paper, independent component analysis (ICA), principal component analysis, auto- and cross-correlation are investigated and compared with respect to their effectiveness in extracting the relevant information from video recordings. Results obtained are compared with those recorded by a modern commercial finger pulse oximeter. It is found that ICA produces the most consistent results. (paper)

  9. Signal recovery in imaging photoplethysmography.

    Science.gov (United States)

    Holton, Benjamin D; Mannapperuma, Kavan; Lesniewski, Peter J; Thomas, John C

    2013-11-01

    Imaging photoplethysmography is an emerging technique for the extraction of biometric information from people using video recordings. The focus is on extracting the cardiac heart rate of the subject by analysing the luminance of the colour video signal and identifying periodic components. Advanced signal processing is needed to recover the information required. In this paper, independent component analysis (ICA), principal component analysis, auto- and cross-correlation are investigated and compared with respect to their effectiveness in extracting the relevant information from video recordings. Results obtained are compared with those recorded by a modern commercial finger pulse oximeter. It is found that ICA produces the most consistent results.

  10. Microsystem for signal processing applications

    Science.gov (United States)

    Frankenstein, B.; Froehlich, K.-J.; Hentschel, D.; Reppe, G.

    2005-05-01

    Acoustic monitoring of technological processes requires methods that eliminate noise as much as possible. Sensor-near signal evaluation can contribute substantially. Frequently, a further necessity exists to integrate the measuring technique in the monitored structure. The solution described contains components for analog preprocessing of acoustic signals, their digitization, algorithms for data reduction, and digital communication. The core component is a digital signal processor (DSP). Digital signal processors perform the algorithms necessary for filtering, down sampling, FFT computation and correlation of spectral components particularly effective. A compact, sensor-near signal processing structure was realized. It meets the Match-X standard, which as specified by the German Association for Mechanical and Plant Engineering (VDMA) for development of micro-technical modules, which can be combined to applicaiton specific systems. The solution is based on AL2O3 ceramic components including different signal processing modules as ADC, as well as memory and power supply. An arbitrary waveform generator has been developed and combined with a power amplifier for piezoelectric transducers in a special module. A further module interfaces to these transducers. It contains a multi-channel preamplifier, some high-pass filters for analog signal processing and an ADC-driver. A Bluetooth communication chip for wireless data transmission and a DiscOnChip module are under construction. As a first application, the combustion behavior of safety-relevant contacts is monitored. A special waveform up to 5MHz is produced and sent to the monitored object. The resulting signal form is evaluated with special algorithms, which extract significant parameters of the signal, and transmitted via CAN-bus.

  11. Experimental angular correlation test of time reversal invariance in neon 19 β decay

    International Nuclear Information System (INIS)

    Schneider, M.B.

    1983-01-01

    The results of a new test of time reversal invariance in 19 Ne nuclear β decay are reported. The triple angular correlation was investigated by observing the decay of polarized 19 Ne. This correlation, whose amplitude is given by the R coefficient, should be zero if time reversal is a good symmetry, neglecting final state interactions. 19 Ne was produced on line through the reaction 19 F(p,n) 19 Ne with 12 MeV protons from the Princeton Cyclotron. The sample was polarized through an atomic beam method and the beta polarimetry was performed with four identical Mott scattering polarimeters. The upper limit for the R coefficient, is 0.079 +/- 0.053 marginally consistent with time reversal invariance. This first measurement of this correlation in nuclear β decay puts a corresponding limit on the value of Im (C/sub S/C/sub A/*) of 0.192 +/- 0.128. The quoted errors are purely statistical, one standard deviation errors. The principal systematic errors, both due to final state electromagnetic interactions and instrumental limitations are discussed. The possibilities for improvements in this experiment, principally in the area of more efficient methods of polarizing 19 Ne, which could improve the result by as much as two orders of magnitude, are discussed

  12. Basic digital signal processing

    CERN Document Server

    Lockhart, Gordon B

    1985-01-01

    Basic Digital Signal Processing describes the principles of digital signal processing and experiments with BASIC programs involving the fast Fourier theorem (FFT). The book reviews the fundamentals of the BASIC program, continuous and discrete time signals including analog signals, Fourier analysis, discrete Fourier transform, signal energy, power. The text also explains digital signal processing involving digital filters, linear time-variant systems, discrete time unit impulse, discrete-time convolution, and the alternative structure for second order infinite impulse response (IIR) sections.

  13. Correlated binomial models and correlation structures

    International Nuclear Information System (INIS)

    Hisakado, Masato; Kitsukawa, Kenji; Mori, Shintaro

    2006-01-01

    We discuss a general method to construct correlated binomial distributions by imposing several consistent relations on the joint probability function. We obtain self-consistency relations for the conditional correlations and conditional probabilities. The beta-binomial distribution is derived by a strong symmetric assumption on the conditional correlations. Our derivation clarifies the 'correlation' structure of the beta-binomial distribution. It is also possible to study the correlation structures of other probability distributions of exchangeable (homogeneous) correlated Bernoulli random variables. We study some distribution functions and discuss their behaviours in terms of their correlation structures

  14. Neural correlates of quality perception for complex speech signals

    CERN Document Server

    Antons, Jan-Niklas

    2015-01-01

    This book interconnects two essential disciplines to study the perception of speech: Neuroscience and Quality of Experience, which to date have rarely been used together for the purposes of research on speech quality perception. In five key experiments, the book demonstrates the application of standard clinical methods in neurophysiology on the one hand, and of methods used in fields of research concerned with speech quality perception on the other. Using this combination, the book shows that speech stimuli with different lengths and different quality impairments are accompanied by physiological reactions related to quality variations, e.g., a positive peak in an event-related potential. Furthermore, it demonstrates that – in most cases – quality impairment intensity has an impact on the intensity of physiological reactions.

  15. Visualizing confusion matrices for multidimensional signal detection correlational methods

    Science.gov (United States)

    Zhou, Yue; Wischgoll, Thomas; Blaha, Leslie M.; Smith, Ross; Vickery, Rhonda J.

    2013-12-01

    Advances in modeling and simulation for General Recognition Theory have produced more data than can be easily visualized using traditional techniques. In this area of psychological modeling, domain experts are struggling to find effective ways to compare large-scale simulation results. This paper describes methods that adapt the web-based D3 visualization framework combined with pre-processing tools to enable domain specialists to more easily interpret their data. The D3 framework utilizes Javascript and scalable vector graphics (SVG) to generate visualizations that can run readily within the web browser for domain specialists. Parallel coordinate plots and heat maps were developed for identification-confusion matrix data, and the results were shown to a GRT expert for an informal evaluation of their utility. There is a clear benefit to model interpretation from these visualizations when researchers need to interpret larger amounts of simulated data.

  16. Signal Processing and Restoration

    NARCIS (Netherlands)

    Biemond, J.; Slump, C.H.; Lagendijk, R.L.; Tolhuizen, L.M.G.M.; de With, P.H.N.

    2004-01-01

    Digital Signal Processing (DSP) concerns the theoretical and practical aspects of representing information-bearing signals in digital form and the use of processors or special purpose hardware to extract that information or to transform the signals in useful ways. Areas where digital signal

  17. Retroactive signaling in short signaling pathways.

    Directory of Open Access Journals (Sweden)

    Jacques-Alexandre Sepulchre

    Full Text Available In biochemical signaling pathways without explicit feedback connections, the core signal transduction is usually described as a one-way communication, going from upstream to downstream in a feedforward chain or network of covalent modification cycles. In this paper we explore the possibility of a new type of signaling called retroactive signaling, offered by the recently demonstrated property of retroactivity in signaling cascades. The possibility of retroactive signaling is analysed in the simplest case of the stationary states of a bicyclic cascade of signaling cycles. In this case, we work out the conditions for which variables of the upstream cycle are affected by a change of the total amount of protein in the downstream cycle, or by a variation of the phosphatase deactivating the same protein. Particularly, we predict the characteristic ranges of the downstream protein, or of the downstream phosphatase, for which a retroactive effect can be observed on the upstream cycle variables. Next, we extend the possibility of retroactive signaling in short but nonlinear signaling pathways involving a few covalent modification cycles.

  18. Signal verification can promote reliable signalling.

    Science.gov (United States)

    Broom, Mark; Ruxton, Graeme D; Schaefer, H Martin

    2013-11-22

    The central question in communication theory is whether communication is reliable, and if so, which mechanisms select for reliability. The primary approach in the past has been to attribute reliability to strategic costs associated with signalling as predicted by the handicap principle. Yet, reliability can arise through other mechanisms, such as signal verification; but the theoretical understanding of such mechanisms has received relatively little attention. Here, we model whether verification can lead to reliability in repeated interactions that typically characterize mutualisms. Specifically, we model whether fruit consumers that discriminate among poor- and good-quality fruits within a population can select for reliable fruit signals. In our model, plants either signal or they do not; costs associated with signalling are fixed and independent of plant quality. We find parameter combinations where discriminating fruit consumers can select for signal reliability by abandoning unprofitable plants more quickly. This self-serving behaviour imposes costs upon plants as a by-product, rendering it unprofitable for unrewarding plants to signal. Thus, strategic costs to signalling are not a prerequisite for reliable communication. We expect verification to more generally explain signal reliability in repeated consumer-resource interactions that typify mutualisms but also in antagonistic interactions such as mimicry and aposematism.

  19. Quantitative evaluation of signal integrity for magnetocardiography

    International Nuclear Information System (INIS)

    Zhang Shulin; Wang Yongliang; Wang Huiwu; Xie Xiaoming; Jiang Shiqin

    2009-01-01

    Magnetocardiography (MCG) is a non-invasive diagnostic tool used to investigate the activity of the heart. For applications in an unshielded environment, in order to extract the very weak signal of interest from the much higher background noise, dedicated hardware configuration and sophisticated signal processing techniques have been developed during the last decades. Being powerful in noise rejection, the signal processing may introduce signal distortions, if not properly designed and applied. However, there is a lack of an effective tool to quantitatively evaluate the signal integrity for MCG at present. In this paper, we have introduced a very simple method by using a small coil driven by a human ECG signal to generate a simulated MCG signal. Three key performance indexes were proposed, which are correlation in time domain, relative heights of different peaks and correlation in frequency domain, to evaluate the MCG system performance quantitatively. This evaluation method was applied to a synthetic gradiometer consisting of a second-order axial gradiometer and three orthogonal reference magnetometers. The evaluation turned out to be very effective in optimizing the parameters for signal processing. In addition, the method can serve as a useful tool for hardware improvement.

  20. Learning to Play Efficient Coarse Correlated Equilibria

    KAUST Repository

    Borowski, Holly P.

    2018-03-10

    The majority of the distributed learning literature focuses on convergence to Nash equilibria. Coarse correlated equilibria, on the other hand, can often characterize more efficient collective behavior than even the best Nash equilibrium. However, there are no existing distributed learning algorithms that converge to specific coarse correlated equilibria. In this paper, we provide one such algorithm, which guarantees that the agents’ collective joint strategy will constitute an efficient coarse correlated equilibrium with high probability. The key to attaining efficient correlated behavior through distributed learning involves incorporating a common random signal into the learning environment.

  1. Clinicopathological correlates of hyperparathyroidism.

    Science.gov (United States)

    Duan, Kai; Gomez Hernandez, Karen; Mete, Ozgur

    2015-10-01

    Hyperparathyroidism is a common endocrine disorder with potential complications on the skeletal, renal, neurocognitive and cardiovascular systems. While most cases (95%) occur sporadically, about 5% are associated with a hereditary syndrome: multiple endocrine neoplasia syndromes (MEN-1, MEN-2A, MEN-4), hyperparathyroidism-jaw tumour syndrome (HPT-JT), familial hypocalciuric hypercalcaemia (FHH-1, FHH-2, FHH-3), familial hypercalciuric hypercalcaemia, neonatal severe hyperparathyroidism and isolated familial hyperparathyroidism. Recently, molecular mechanisms underlying possible tumour suppressor genes (MEN1, CDC73/HRPT2, CDKIs, APC, SFRPs, GSK3β, RASSF1A, HIC1, RIZ1, WT1, CaSR, GNA11, AP2S1) and proto-oncogenes (CCND1/PRAD1, RET, ZFX, CTNNB1, EZH2) have been uncovered in the pathogenesis of hyperparathyroidism. While bi-allelic inactivation of CDC73/HRPT2 seems unique to parathyroid malignancy, aberrant activation of cyclin D1 and Wnt/β-catenin signalling has been reported in benign and malignant parathyroid tumours. Clinicopathological correlates of primary hyperparathyroidism include parathyroid adenoma (80-85%), hyperplasia (10-15%) and carcinoma (hyperparathyroidism generally presents with diffuse parathyroid hyperplasia, whereas tertiary hyperparathyroidism reflects the emergence of autonomous parathyroid hormone (PTH)-producing neoplasm(s) from secondary parathyroid hyperplasia. Surgical resection of abnormal parathyroid tissue remains the only curative treatment in primary hyperparathyroidism, and parathyroidectomy specimens are frequently encountered in this setting. Clinical and biochemical features, including intraoperative PTH levels, number, weight and size of the affected parathyroid gland(s), are crucial parameters to consider when rendering an accurate diagnosis of parathyroid proliferations. This review provides an update on the expanding knowledge of hyperparathyroidism and highlights the clinicopathological correlations of this prevalent

  2. Unmixing binocular signals

    Directory of Open Access Journals (Sweden)

    Sidney R Lehky

    2011-08-01

    Full Text Available Incompatible images presented to the two eyes lead to perceptual oscillations in which one image at a time is visible. Early models portrayed this binocular rivalry as involving reciprocal inhibition between monocular representations of images, occurring at an early visual stage prior to binocular mixing. However, psychophysical experiments found conditions where rivalry could also occur at a higher, more abstract level of representation. In those cases, the rivalry was between image representations dissociated from eye-of-origin information, rather than between monocular representations from the two eyes. Moreover, neurophysiological recordings found the strongest rivalry correlate in inferotemporal cortex, a high-level, predominantly binocular visual area involved in object recognition, rather than early visual structures. An unresolved issue is how can the separate identities of the two images be maintained after binocular mixing in order for rivalry to be possible at higher levels? Here we demonstrate that after the two images are mixed, they can be unmixed at any subsequent stage using a physiologically plausible nonlinear signal-processing algorithm, non-negative matrix factorization, previously proposed for parsing object parts during object recognition. The possibility that unmixed left and right images can be regenerated at late stages within the visual system provides a mechanism for creating various binocular representations and interactions de novo in different cortical areas for different purposes, rather than inheriting then from early areas. This is a clear example how nonlinear algorithms can lead to highly non-intuitive behavior in neural information processing.

  3. Signal Enhancement with Variable Span Linear Filters

    DEFF Research Database (Denmark)

    Benesty, Jacob; Christensen, Mads Græsbøll; Jensen, Jesper Rindom

    . Variable span filters combine the ideas of optimal linear filters with those of subspace methods, as they involve the joint diagonalization of the correlation matrices of the desired signal and the noise. The book shows how some well-known filter designs, e.g. the minimum distortion, maximum signal...... the time and STFT domains, and, lastly, in time-domain binaural enhancement. In these contexts, the properties of these filters are analyzed in terms of their noise reduction capabilities and desired signal distortion, and the analyses are validated and further explored in simulations....

  4. Signal Processing in the Linear Statistical Model

    Science.gov (United States)

    1994-11-04

    Covariance Bounds," Proc 07th Asilo - mar Conf on Signals, Systems, and Computers, Pacific Grove, CA (November 1993). [MuS9l] C. T. Mullis and L. L. Scharf...Transforms," Proc Asilo - mar Con. on Signals, Systems, and Computers, Asilomar, CA (November 1991). [SpS94] M. Spurbeck and L. L. Scharf, "Least Squares...McWhorter and L. L. Scharf, "Multiwindow Estimators of Correlation," Proc 28th Annual Asilo - mar Conf on Signals, Systems, and Computers, Asilomar, CA

  5. Signal sciences workshop. Proceedings

    International Nuclear Information System (INIS)

    Candy, J.V.

    1997-01-01

    This meeting is aimed primarily at signal processing and controls. The technical program for the 1997 Workshop includes a variety of efforts in the Signal Sciences with applications in the Microtechnology Area a new program at LLNL and a future area of application for both Signal/Image Sciences. Special sessions organized by various individuals in Seismic and Optical Signal Processing as well as Micro-Impulse Radar Processing highlight the program, while the speakers at the Signal Processing Applications session discuss various applications of signal processing/control to real world problems. For the more theoretical, a session on Signal Processing Algorithms was organized as well as for the more pragmatic, featuring a session on Real-Time Signal Processing

  6. Traffic signal timing manual

    Science.gov (United States)

    2008-06-01

    This report serves as a comprehensive guide to traffic signal timing and documents the tasks completed in association with its development. The focus of this document is on traffic signal control principles, practices, and procedures. It describes th...

  7. Signal sciences workshop proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.

    1997-05-01

    This meeting is aimed primarily at signal processing and controls. The technical program for the 1997 Workshop includes a variety of efforts in the Signal Sciences with applications in the Microtechnology Area a new program at LLNL and a future area of application for both Signal/Image Sciences. Special sessions organized by various individuals in Seismic and Optical Signal Processing as well as Micro-Impulse Radar Processing highlight the program, while the speakers at the Signal Processing Applications session discuss various applications of signal processing/control to real world problems. For the more theoretical, a session on Signal Processing Algorithms was organized as well as for the more pragmatic, featuring a session on Real-Time Signal Processing.

  8. Sonic Hedgehog signaling in advanced prostate cancer.

    Science.gov (United States)

    Datta, S; Datta, M W

    2006-02-01

    The Hedgehog family of growth factors activate a highly conserved signaling system for cell-cell communication that regulates cell proliferation and differentiation during development. Abnormal activation of the Hedgehog pathway has been demonstrated in a variety of human tumors, including those of the skin, brain, lung and digestive tract. Hedgehog pathway activity in these tumors is required for cancer cell proliferation and tumor growth. Recent studies have uncovered the role for Hedgehog signaling in advanced prostate cancer and demonstrated that autocrine signaling by tumor cells is required for proliferation, viability, and invasive behavior. The level of Hedgehog activity correlates with the severity of the tumor and is both necessary and sufficient for metastatic behavior. Blockade of Hedgehog signaling leads to tumor shrinkage and remission in preclinical tumor xenograft models. Thus, Hedgehog signaling represents a novel pathway in prostate cancer that offers opportunities for prognostic biomarker development, drug targeting and therapeutic response monitoring.

  9. Low power digital signal processing

    DEFF Research Database (Denmark)

    Paker, Ozgun

    2003-01-01

    This thesis introduces a novel approach to programmable and low power platform design for audio signal processing, in particular hearing aids. The proposed programmable platform is a heterogeneous multiprocessor architecture consisting of small and simple instruction set processors called mini......-cores as well as standard DSP/CPU-cores that communicate using message passing. The work has been based on a study of the algorithm suite covering the application domain. The observation of dominant tasks for certain algorithms (FIR, IIR, correlation, etc.) that require custom computational units and special...... data addressing capabilities lead to the design of low power mini-cores. The algorithm suite also consisted of less demanding and/or irregular algorithms (LMS, compression) that required subsample rate signal processing justifying the use of a DSP/CPU-core. The thesis also contributes to the recent...

  10. Biomedical signal processing

    CERN Document Server

    Akay, Metin

    1994-01-01

    Sophisticated techniques for signal processing are now available to the biomedical specialist! Written in an easy-to-read, straightforward style, Biomedical Signal Processing presents techniques to eliminate background noise, enhance signal detection, and analyze computer data, making results easy to comprehend and apply. In addition to examining techniques for electrical signal analysis, filtering, and transforms, the author supplies an extensive appendix with several computer programs that demonstrate techniques presented in the text.

  11. Quantitative measurement of intervertebral disc signal using MRI

    International Nuclear Information System (INIS)

    Niemelaeinen, R.; Videman, T.; Dhillon, S.S.; Battie, M.C.

    2008-01-01

    Aim: To investigate the spinal cord as an alternative intra-body reference to cerebrospinal fluid (CSF) in evaluating thoracic disc signal intensity. Materials and methods: T2-weighted magnetic resonance imaging (MRI) images of T6-T12 were obtained using 1.5 T machines for a population-based sample of 523 men aged 35-70 years. Quantitative data on the signal intensities were acquired using an image analysis program (SpEx (copy right) ). A random sample of 30 subjects and intraclass correlation coeffcients (ICC) were used to examine the repeatability of the spinal cord measurements. The validity of using the spinal cord as a reference was examined by correlating cord and CSF samples. Finally, thoracic disc signal was validated by correlating it with age without adjustment and adjusting for either cord or CSF. Pearson's r was used for correlational analyses. Results: The repeatability of the spinal cord signal measurements was extremely high (≥0.99). The correlations between the signals of spinal cord and CSF by level were all above 0.9. The spinal cord-adjusted disc signal and age correlated similarly with CSF-adjusted disc signal and age (r = -0.30 to -0.40 versus r = -0.26 to -0.36). Conclusion: Adjacent spinal cord is a good alternative reference to the current reference standard, CSF, for quantitative measurements of disc signal intensity. Clearly fewer levels were excluded when using spinal cord as compared to CSF due to missing reference samples

  12. Optimal Signal Quality Index for Photoplethysmogram Signals

    Directory of Open Access Journals (Sweden)

    Mohamed Elgendi

    2016-09-01

    Full Text Available A photoplethysmogram (PPG is a noninvasive circulatory signal related to the pulsatile volume of blood in tissue and is typically collected by pulse oximeters. PPG signals collected via mobile devices are prone to artifacts that negatively impact measurement accuracy, which can lead to a significant number of misleading diagnoses. Given the rapidly increased use of mobile devices to collect PPG signals, developing an optimal signal quality index (SQI is essential to classify the signal quality from these devices. Eight SQIs were developed and tested based on: perfusion, kurtosis, skewness, relative power, non-stationarity, zero crossing, entropy, and the matching of systolic wave detectors. Two independent annotators annotated all PPG data (106 recordings, 60 s each and a third expert conducted the adjudication of differences. The independent annotators labeled each PPG signal with one of the following labels: excellent, acceptable or unfit for diagnosis. All indices were compared using Mahalanobis distance, linear discriminant analysis, quadratic discriminant analysis, and support vector machine with leave-one-out cross-validation. The skewness index outperformed the other seven indices in differentiating between excellent PPG and acceptable, acceptable combined with unfit, and unfit recordings, with overall F 1 scores of 86.0%, 87.2%, and 79.1%, respectively.

  13. Optimal Signal Quality Index for Photoplethysmogram Signals.

    Science.gov (United States)

    Elgendi, Mohamed

    2016-09-22

    A photoplethysmogram (PPG) is a noninvasive circulatory signal related to the pulsatile volume of blood in tissue and is typically collected by pulse oximeters. PPG signals collected via mobile devices are prone to artifacts that negatively impact measurement accuracy, which can lead to a significant number of misleading diagnoses. Given the rapidly increased use of mobile devices to collect PPG signals, developing an optimal signal quality index (SQI) is essential to classify the signal quality from these devices. Eight SQIs were developed and tested based on: perfusion, kurtosis, skewness, relative power, non-stationarity, zero crossing, entropy, and the matching of systolic wave detectors. Two independent annotators annotated all PPG data (106 recordings, 60 s each) and a third expert conducted the adjudication of differences. The independent annotators labeled each PPG signal with one of the following labels: excellent, acceptable or unfit for diagnosis. All indices were compared using Mahalanobis distance, linear discriminant analysis, quadratic discriminant analysis, and support vector machine with leave-one-out cross-validation. The skewness index outperformed the other seven indices in differentiating between excellent PPG and acceptable, acceptable combined with unfit, and unfit recordings, with overall F 1 scores of 86.0%, 87.2%, and 79.1%, respectively.

  14. Location Verification Systems Under Spatially Correlated Shadowing

    OpenAIRE

    Yan, Shihao; Nevat, Ido; Peters, Gareth W.; Malaney, Robert

    2014-01-01

    The verification of the location information utilized in wireless communication networks is a subject of growing importance. In this work we formally analyze, for the first time, the performance of a wireless Location Verification System (LVS) under the realistic setting of spatially correlated shadowing. Our analysis illustrates that anticipated levels of correlated shadowing can lead to a dramatic performance improvement of a Received Signal Strength (RSS)-based LVS. We also analyze the per...

  15. Cross-correlation in flow-injection analysis with parallel flow streams and amperometric detection.

    Science.gov (United States)

    McKean, R E; Curran, D J

    1992-03-01

    Cross-correlation was implemented for flow-injection analysis by using two parallel flow lines, each with amperometric detectors, and driven by peristaltic pumps. One flow line was used to generate the reference signal for an analog correlator circuit and the other to generate the analyte signal. Cross-correlation was performed by multiplying these signals together at a time delay of zero, followed by low pass filtering. Using dopamine as a test system, improvements in signal-to-noise ratios of about two orders of magnitude were found for the correlation signal over the direct measurement of the electrode current.

  16. The Signal Distribution System

    CERN Document Server

    Belohrad, D; CERN. Geneva. AB Department

    2005-01-01

    For the purpose of LHC signal observation and high frequency signal distribution, the Signal Distribution System (SDS) was built. The SDS can contain up to 5 switching elements, where each element allows the user to switch between one of the maximum 8 bi-directional signals. The coaxial relays are used to switch the signals. Depending of the coaxial relay type used, the transfer bandwidth can go up to 18GHz. The SDS is controllable via TCP/IP, parallel port, or locally by rotary switch.

  17. Acoustic Signals and Systems

    DEFF Research Database (Denmark)

    2008-01-01

    The Handbook of Signal Processing in Acoustics will compile the techniques and applications of signal processing as they are used in the many varied areas of Acoustics. The Handbook will emphasize the interdisciplinary nature of signal processing in acoustics. Each Section of the Handbook...... will present topics on signal processing which are important in a specific area of acoustics. These will be of interest to specialists in these areas because they will be presented from their technical perspective, rather than a generic engineering approach to signal processing. Non-specialists, or specialists...

  18. Method of signal analysis

    International Nuclear Information System (INIS)

    Berthomier, Charles

    1975-01-01

    A method capable of handling the amplitude and the frequency time laws of a certain kind of geophysical signals is described here. This method is based upon the analytical signal idea of Gabor and Ville, which is constructed either in the time domain by adding an imaginary part to the real signal (in-quadrature signal), or in the frequency domain by suppressing negative frequency components. The instantaneous frequency of the initial signal is then defined as the time derivative of the phase of the analytical signal, and his amplitude, or envelope, as the modulus of this complex signal. The method is applied to three types of magnetospheric signals: chorus, whistlers and pearls. The results obtained by analog and numerical calculations are compared to results obtained by classical systems using filters, i.e. based upon a different definition of the concept of frequency. The precision with which the frequency-time laws are determined leads then to the examination of the principle of the method and to a definition of instantaneous power density spectrum attached to the signal, and to the first consequences of this definition. In this way, a two-dimensional representation of the signal is introduced which is less deformed by the analysis system properties than the usual representation, and which moreover has the advantage of being obtainable practically in real time [fr

  19. Photon correlation holography.

    Science.gov (United States)

    Naik, Dinesh N; Singh, Rakesh Kumar; Ezawa, Takahiro; Miyamoto, Yoko; Takeda, Mitsuo

    2011-01-17

    Unconventional holography called photon correlation holography is proposed and experimentally demonstrated. Using photon correlation, i.e. intensity correlation or fourth order correlation of optical field, a 3-D image of the object recorded in a hologram is reconstructed stochastically with illumination through a random phase screen. Two different schemes for realizing photon correlation holography are examined by numerical simulations, and the experiment was performed for one of the reconstruction schemes suitable for the experimental proof of the principle. The technique of photon correlation holography provides a new insight into how the information is embedded in the spatial as well as temporal correlation of photons in the stochastic pseudo thermal light.

  20. Bayesian Correlation Analysis for Sequence Count Data.

    Directory of Open Access Journals (Sweden)

    Daniel Sánchez-Taltavull

    Full Text Available Evaluating the similarity of different measured variables is a fundamental task of statistics, and a key part of many bioinformatics algorithms. Here we propose a Bayesian scheme for estimating the correlation between different entities' measurements based on high-throughput sequencing data. These entities could be different genes or miRNAs whose expression is measured by RNA-seq, different transcription factors or histone marks whose expression is measured by ChIP-seq, or even combinations of different types of entities. Our Bayesian formulation accounts for both measured signal levels and uncertainty in those levels, due to varying sequencing depth in different experiments and to varying absolute levels of individual entities, both of which affect the precision of the measurements. In comparison with a traditional Pearson correlation analysis, we show that our Bayesian correlation analysis retains high correlations when measurement confidence is high, but suppresses correlations when measurement confidence is low-especially for entities with low signal levels. In addition, we consider the influence of priors on the Bayesian correlation estimate. Perhaps surprisingly, we show that naive, uniform priors on entities' signal levels can lead to highly biased correlation estimates, particularly when different experiments have widely varying sequencing depths. However, we propose two alternative priors that provably mitigate this problem. We also prove that, like traditional Pearson correlation, our Bayesian correlation calculation constitutes a kernel in the machine learning sense, and thus can be used as a similarity measure in any kernel-based machine learning algorithm. We demonstrate our approach on two RNA-seq datasets and one miRNA-seq dataset.

  1. Echoes in correlated neural systems

    International Nuclear Information System (INIS)

    Helias, M; Tetzlaff, T; Diesmann, M

    2013-01-01

    Correlations are employed in modern physics to explain microscopic and macroscopic phenomena, like the fractional quantum Hall effect and the Mott insulator state in high temperature superconductors and ultracold atoms. Simultaneously probed neurons in the intact brain reveal correlations between their activity, an important measure to study information processing in the brain that also influences the macroscopic signals of neural activity, like the electroencephalogram (EEG). Networks of spiking neurons differ from most physical systems: the interaction between elements is directed, time delayed, mediated by short pulses and each neuron receives events from thousands of neurons. Even the stationary state of the network cannot be described by equilibrium statistical mechanics. Here we develop a quantitative theory of pairwise correlations in finite-sized random networks of spiking neurons. We derive explicit analytic expressions for the population-averaged cross correlation functions. Our theory explains why the intuitive mean field description fails, how the echo of single action potentials causes an apparent lag of inhibition with respect to excitation and how the size of the network can be scaled while maintaining its dynamical state. Finally, we derive a new criterion for the emergence of collective oscillations from the spectrum of the time-evolution propagator. (paper)

  2. Phase synchronization of instrumental music signals

    Science.gov (United States)

    Mukherjee, Sayan; Palit, Sanjay Kumar; Banerjee, Santo; Ariffin, M. R. K.; Bhattacharya, D. K.

    2014-06-01

    Signal analysis is one of the finest scientific techniques in communication theory. Some quantitative and qualitative measures describe the pattern of a music signal, vary from one to another. Same musical recital, when played by different instrumentalists, generates different types of music patterns. The reason behind various patterns is the psycho-acoustic measures - Dynamics, Timber, Tonality and Rhythm, varies in each time. However, the psycho-acoustic study of the music signals does not reveal any idea about the similarity between the signals. For such cases, study of synchronization of long-term nonlinear dynamics may provide effective results. In this context, phase synchronization (PS) is one of the measures to show synchronization between two non-identical signals. In fact, it is very critical to investigate any other kind of synchronization for experimental condition, because those are completely non identical signals. Also, there exists equivalence between the phases and the distances of the diagonal line in Recurrence plot (RP) of the signals, which is quantifiable by the recurrence quantification measure τ-recurrence rate. This paper considers two nonlinear music signals based on same raga played by two eminent sitar instrumentalists as two non-identical sources. The psycho-acoustic study shows how the Dynamics, Timber, Tonality and Rhythm vary for the two music signals. Then, long term analysis in the form of phase space reconstruction is performed, which reveals the chaotic phase spaces for both the signals. From the RP of both the phase spaces, τ-recurrence rate is calculated. Finally by the correlation of normalized tau-recurrence rate of their 3D phase spaces and the PS of the two music signals has been established. The numerical results well support the analysis.

  3. Hadron correlations from recombination

    Energy Technology Data Exchange (ETDEWEB)

    Fries, Rainer J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2005-01-01

    Quark recombination is a successful model to describe the hadronization of a deconfined quark gluon plasma. Jet-like dihadron correlations measured at RHIC provide a challenge for this picture. We discuss how correlations between hadrons can arise from correlations between partons before hadronization. An enhancement of correlations through the recombination process, similar to the enhancement of elliptic flow is found. Hot spots from completely or partially quenched jets are a likely source of such parton correlations.

  4. Fourier-correlation imaging

    Science.gov (United States)

    Braun, Daniel; Monjid, Younes; Rougé, Bernard; Kerr, Yann

    2018-02-01

    We investigated whether correlations between the Fourier components at slightly shifted frequencies of the fluctuations of the electric field measured with a one-dimensional antenna array on board a satellite flying over a plane allow one to measure the two-dimensional brightness temperature as a function of position in the plane. We found that the achievable spatial resolution that resulted from just two antennas is on the order of h χ , with χ = c / ( Δ r ω 0 ) , both in the direction of the flight of the satellite and in the direction perpendicular to it, where Δ r is the distance between the antennas, ω0 is the central frequency, h is the height of the satellite over the plane, and c is the speed of light. Two antennas separated by a distance of about 100 m on a satellite flying with a speed of a few km/s at a height of the order of 1000 km and a central frequency of order GHz allow, therefore, the imaging of the brightness temperature on the surface of Earth with a resolution of the order of 1 km. For a single point source, the relative radiometric resolution is on the order of √{ χ} , but, for a uniform temperature field in a half plane left or right of the satellite track, it is only on the order of 1 / χ 3 / 2 , which indicates that two antennas do not suffice for a precise reconstruction of the temperature field. Several ideas are discussed regarding how the radiometric resolution could be enhanced. In particular, having N antennas all separated by at least a distance on the order of the wave-length allows one to increase the signal-to-noise ratio by a factor of order N but requires averaging over N2 temperature profiles obtained from as many pairs of antennas.

  5. Correlation control theory of chaotic laser systems

    International Nuclear Information System (INIS)

    Li Fuli.

    1986-04-01

    A novel control theory of chaotic systems is studied. The correlation functions are calculated and used as feedback signals of the chaotic lasers. Computer experiments have shown that in this way the chaotic systems can be controlled to have time-independent output when the external control parameters are in chaotic domain. (author)

  6. Wnt signaling in cancer

    Science.gov (United States)

    Zhan, T; Rindtorff, N; Boutros, M

    2017-01-01

    Wnt signaling is one of the key cascades regulating development and stemness, and has also been tightly associated with cancer. The role of Wnt signaling in carcinogenesis has most prominently been described for colorectal cancer, but aberrant Wnt signaling is observed in many more cancer entities. Here, we review current insights into novel components of Wnt pathways and describe their impact on cancer development. Furthermore, we highlight expanding functions of Wnt signaling for both solid and liquid tumors. We also describe current findings how Wnt signaling affects maintenance of cancer stem cells, metastasis and immune control. Finally, we provide an overview of current strategies to antagonize Wnt signaling in cancer and challenges that are associated with such approaches. PMID:27617575

  7. MRI of the breast - histopathologic correlation

    International Nuclear Information System (INIS)

    Heywang, S.H.; Fenzl, G.; Hahn, D.; Beck, R.; Krischke, I.; Bassermann, R.; Nathrath, W.; Eiermann, W.

    1987-01-01

    132 solid breast masses have been examined at our institution by MR and have consequently been histopathologically correlated. T1- and T2-weighted SE and multiecho sequences have been evaluated visually. It was found that signal intensities of tissues on T2-weighted images correlated with the contents of fibrosis, cells or water. Thus in some lesions (which consisted of different tissue components), a characteristic internal structure was visible on T2-weighted images, reflecting their histopathologic structure. Corresponding to their different composition, differences of signal intensity have also been noted between those fibroadenomas with a high contents of fibrosis and all other well-circumscribed breast lesions (fibroadenomas, carcinomas). However, for the majority of lesions with irregular contours a discrimination based on signal intensities or calculated T1- and T2-values did not seem possible. This overlap can also be explained by the macroscopically similar composition (amount of fibrosis, water or cells) of benign and malignant irregular lesions. (orig.)

  8. Conception and fabrication of a real time automatic correlator (multi-correlator)

    International Nuclear Information System (INIS)

    Berthier, D.

    1967-10-01

    The purpose of this work is to elaborate a specific computer able to display the real.time correlation function of two variables represented by two electrical signals. The various functions to be done are dealt with the best suited technology: delays from numerical method, hybrid multiplication, analog integration. This method proved very versatile so that it has been possible to modify the circuits with more performing components without changing the general conception of the whole system. In particular, the bandwidth, which was originally 125 kHz (1966) is now 1 MHz and will be 5 MHz, January 1968. Many results are obtained from the correlator such as: - determination of pulse responses of linear systems (1. and 2. order filters, oscillating circuits); - extraction of signals from noise; - measurement of time and space correlation in a turbulent plasma; - treatment of electro-biological signals. (author) [fr

  9. Biomedical signals and systems

    CERN Document Server

    Tranquillo, Joseph V

    2013-01-01

    Biomedical Signals and Systems is meant to accompany a one-semester undergraduate signals and systems course. It may also serve as a quick-start for graduate students or faculty interested in how signals and systems techniques can be applied to living systems. The biological nature of the examples allows for systems thinking to be applied to electrical, mechanical, fluid, chemical, thermal and even optical systems. Each chapter focuses on a topic from classic signals and systems theory: System block diagrams, mathematical models, transforms, stability, feedback, system response, control, time

  10. Digital signal processing

    CERN Document Server

    O'Shea, Peter; Hussain, Zahir M

    2011-01-01

    In three parts, this book contributes to the advancement of engineering education and that serves as a general reference on digital signal processing. Part I presents the basics of analog and digital signals and systems in the time and frequency domain. It covers the core topics: convolution, transforms, filters, and random signal analysis. It also treats important applications including signal detection in noise, radar range estimation for airborne targets, binary communication systems, channel estimation, banking and financial applications, and audio effects production. Part II considers sel

  11. Geolocation of RF signals

    CERN Document Server

    Progri, Ilir

    2011-01-01

    ""Geolocation of RF Signals - Principles and Simulations"" offers an overview of the best practices and innovative techniques in the art and science of geolocation over the last twenty years. It covers all research and development aspects including theoretical analysis, RF signals, geolocation techniques, key block diagrams, and practical principle simulation examples in the frequency band from 100 MHz to 18 GHz or even 60 GHz. Starting with RF signals, the book progressively examines various signal bands - such as VLF, LF, MF, HF, VHF, UHF, L, S, C, X, Ku, and, K and the corresponding geoloca

  12. An Analog Correlator for Ultra-Wideband Receivers

    Directory of Open Access Journals (Sweden)

    Tu Chunjiang

    2005-01-01

    Full Text Available We present a new analog circuit exhibiting high bandwidth and low distortion, specially designed for signal correlation in an ultra-wideband receiver front end. The ultra-wideband short impulse signals are correlated with a local pulse template by the correlator. A comparator then samples the output for signal detection. A typical Gilbert mixer core is adopted for multiplication of broadband signals up to . As a result of synchronization of the received signal and the local template, the output voltage level after integration and sampling can reach up to , which is sufficient for detection by the comparator. The circuit dissipates about from double voltage supplies of and using SiGe BiCMOS technology. Simulation results are presented to show the feasibility of this circuit design for use in ultra-wideband receivers.

  13. AR Signaling in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Bilal Rahim

    2017-02-01

    Full Text Available Androgen receptor (AR, a member of the steroid hormone receptor family status has become increasingly important as both a prognostic marker and potential therapeutic target in breast cancer. AR is expressed in up to 90% of estrogen receptor (ER positive breast cancer, and to a lesser degree, human epidermal growth factor 2 (HER2 amplified tumors. In the former, AR signaling has been correlated with a better prognosis given its inhibitory activity in estrogen dependent disease, though conversely has also been shown to increase resistance to anti-estrogen therapies such as tamoxifen. AR blockade can mitigate this resistance, and thus serves as a potential target in ER-positive breast cancer. In HER2 amplified breast cancer, studies are somewhat conflicting, though most show either no effect or are associated with poorer survival. Much of the available data on AR signaling is in triple-negative breast cancer (TNBC, which is an aggressive disease with inferior outcomes comparative to other breast cancer subtypes. At present, there are no approved targeted therapies in TNBC, making study of the AR signaling pathway compelling. Gene expression profiling studies have also identified a luminal androgen receptor (LAR subtype that is dependent on AR signaling in TNBC. Regardless, there seems to be an association between AR expression and improved outcomes in TNBC. Despite lower pathologic complete response (pCR rates with neoadjuvant therapy, patients with AR-expressing TNBC have been shown to have a better prognosis than those that are AR-negative. Clinical studies targeting AR have shown somewhat promising results. In this paper we review the literature on the biology of AR in breast cancer and its prognostic and predictive roles. We also present our thoughts on therapeutic strategies.

  14. Signaling in symbiosis

    NARCIS (Netherlands)

    Limpens, E.H.M.; Bisseling, T.

    2003-01-01

    In recent years, the major focus in nodulation research has been on the genetic dissection of Nod-factor signaling. Components of this pathway appear to be shared with signaling processes that are induced during the formation of mycorrhiza. With the cloning of orthologs of the NIN and DMI2 genes

  15. SignalR blueprints

    CERN Document Server

    Ingebrigtsen, Einar

    2015-01-01

    This book is designed for software developers, primarily those with knowledge of C#, .NET, and JavaScript. Good knowledge and understanding of SignalR is assumed to allow efficient programming of core elements and applications in SignalR.

  16. Digital Signal Processors

    Indian Academy of Sciences (India)

    A computer controlling the motion of a satellite should acquire signals from the satellite while it is in motion, compute corrections (if required) to the trajectory and send control signals back within a specified time for effective control. Delays may be fatal to ..... emulators and system evaluation tools have facilitated concurrent.

  17. Ubiquitination in apoptosis signaling

    NARCIS (Netherlands)

    van de Kooij, L.W.

    2014-01-01

    The work described in this thesis focuses on ubiquitination and protein degradation, with an emphasis on how these processes regulate apoptosis signaling. More specifically, our aims were: 1. To increase the understanding of ubiquitin-mediated regulation of apoptosis signaling. 2. To identify the E3

  18. Second-hand signals

    DEFF Research Database (Denmark)

    Bergenholtz, Carsten

    2014-01-01

    used by various agents in their search for and assessment of products and firms. I conclude by arguing how this second‐hand nature of signals goes beyond a simple dyadic focus on senders and receivers of signals, and thus elucidates the more complex interrelations of the various types of agents...

  19. Quantum cloning without signaling

    OpenAIRE

    Gisin, Nicolas

    1998-01-01

    Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\\v{z}ek-Hillery QCM.

  20. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital

  1. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2010-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital

  2. Optimal fault signal estimation

    NARCIS (Netherlands)

    Stoorvogel, Antonie Arij; Niemann, H.H.; Saberi, A.; Sannuti, P.

    2002-01-01

    We consider here both fault identification and fault signal estimation. Regarding fault identification, we seek either exact or almost fault identification. On the other hand, regarding fault signal estimation, we seek either $H_2$ optimal, $H_2$ suboptimal or Hinfinity suboptimal estimation. By

  3. Macroevolution of perfume signalling in orchid bees.

    Science.gov (United States)

    Weber, Marjorie G; Mitko, Lukasz; Eltz, Thomas; Ramírez, Santiago R

    2016-11-01

    Theory predicts that both stabilising selection and diversifying selection jointly contribute to the evolution of sexual signalling traits by (1) maintaining the integrity of communication signals within species and (2) promoting the diversification of traits among lineages. However, for many important signalling traits, little is known about whether these dynamics translate into predictable macroevolutionary signatures. Here, we test for macroevolutionary patterns consistent with sexual signalling theory in the perfume signals of neotropical orchid bees, a group well studied for their chemical sexual communication. Our results revealed both high species-specificity and elevated rates of evolution in perfume signals compared to nonsignalling traits. Perfume complexity was correlated with the number of congeners in a species' range, suggesting that perfume evolution may be tied to the remarkably high number of orchid bee species coexisting together in some neotropical communities. Finally, sister-pair comparisons were consistent with both rapid divergence at speciation and character displacement upon secondary contact. Together, our results provide new insight into the macroevolution of sexual signalling in insects. © 2016 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  4. Correlation of near-Earth proton enhancements >100 MeV with parameters of solar microwave bursts

    Science.gov (United States)

    Grechnev, Victor; Kiselev, Valentin; Meshalkina, Nataliya; Chertok, Ilya

    2017-09-01

    We analyze the relations between various combinations of peak fluxes and fluences of solar microwave bursts at 35 GHz recorded with the Nobeyama Radio Polarimeters during 1990–2015, and corresponding parameters of proton enhancements with E>100 MeV exceeding 0.1 pfu registered by GOES monitors in near-Earth environment. The highest correlation has been found between the microwave and proton fluences. This fact reflects a dependence of the total number of protons on the total duration of the acceleration process. In the events with strong flares, the correlation coefficients of proton fluences with microwave and soft X-ray fluences are higher than those with speeds of coronal mass ejections. The results indicate a statistically larger contribution of flare processes to acceleration of high-energy protons. Acceleration by shock waves seems to be less important at high energies in events associated with strong flares, although its contribution probably prevails in weaker events. The probability of a detectable proton enhancement was found to directly depend on the peak flux and duration of a microwave burst. This can be used for diagnostics of proton enhancements based on microwave observations.

  5. Neutron signal transfer analysis

    CERN Document Server

    Pleinert, H; Lehmann, E

    1999-01-01

    A new method called neutron signal transfer analysis has been developed for quantitative determination of hydrogenous distributions from neutron radiographic measurements. The technique is based on a model which describes the detector signal obtained in the measurement as a result of the action of three different mechanisms expressed by signal transfer functions. The explicit forms of the signal transfer functions are determined by Monte Carlo computer simulations and contain only the distribution as a variable. Therefore an unknown distribution can be determined from the detector signal by recursive iteration. This technique provides a simple and efficient tool for analysis of this type while also taking into account complex effects due to the energy dependency of neutron interaction and single and multiple scattering. Therefore this method provides an efficient tool for precise quantitative analysis using neutron radiography, as for example quantitative determination of moisture distributions in porous buil...

  6. Molecular and Cellular Signaling

    CERN Document Server

    Beckerman, Martin

    2005-01-01

    A small number of signaling pathways, no more than a dozen or so, form a control layer that is responsible for all signaling in and between cells of the human body. The signaling proteins belonging to the control layer determine what kinds of cells are made during development and how they function during adult life. Malfunctions in the proteins belonging to the control layer are responsible for a host of human diseases ranging from neurological disorders to cancers. Most drugs target components in the control layer, and difficulties in drug design are intimately related to the architecture of the control layer. Molecular and Cellular Signaling provides an introduction to molecular and cellular signaling in biological systems with an emphasis on the underlying physical principles. The text is aimed at upper-level undergraduates, graduate students and individuals in medicine and pharmacology interested in broadening their understanding of how cells regulate and coordinate their core activities and how diseases ...

  7. Adaptive signal processor

    Energy Technology Data Exchange (ETDEWEB)

    Walz, H.V.

    1980-07-01

    An experimental, general purpose adaptive signal processor system has been developed, utilizing a quantized (clipped) version of the Widrow-Hoff least-mean-square adaptive algorithm developed by Moschner. The system accommodates 64 adaptive weight channels with 8-bit resolution for each weight. Internal weight update arithmetic is performed with 16-bit resolution, and the system error signal is measured with 12-bit resolution. An adapt cycle of adjusting all 64 weight channels is accomplished in 8 ..mu..sec. Hardware of the signal processor utilizes primarily Schottky-TTL type integrated circuits. A prototype system with 24 weight channels has been constructed and tested. This report presents details of the system design and describes basic experiments performed with the prototype signal processor. Finally some system configurations and applications for this adaptive signal processor are discussed.

  8. Adaptive signal processor

    International Nuclear Information System (INIS)

    Walz, H.V.

    1980-07-01

    An experimental, general purpose adaptive signal processor system has been developed, utilizing a quantized (clipped) version of the Widrow-Hoff least-mean-square adaptive algorithm developed by Moschner. The system accommodates 64 adaptive weight channels with 8-bit resolution for each weight. Internal weight update arithmetic is performed with 16-bit resolution, and the system error signal is measured with 12-bit resolution. An adapt cycle of adjusting all 64 weight channels is accomplished in 8 μsec. Hardware of the signal processor utilizes primarily Schottky-TTL type integrated circuits. A prototype system with 24 weight channels has been constructed and tested. This report presents details of the system design and describes basic experiments performed with the prototype signal processor. Finally some system configurations and applications for this adaptive signal processor are discussed

  9. Defective Suppressor of Cytokine Signaling 1 Signaling Contributes to the Pathogenesis of Systemic Lupus Erythematosus

    Directory of Open Access Journals (Sweden)

    Huixia Wang

    2017-10-01

    Full Text Available Systemic lupus erythematosus (SLE is a complex autoimmune disease involving injuries in multiple organs and systems. Exaggerated inflammatory responses are characterized as end-organ damage in patients with SLE. Although the explicit pathogenesis of SLE remains unclear, increasing evidence suggests that dysregulation of cytokine signals contributes to the progression of SLE through the Janus kinase/signal transducer and activator of transcription (STAT signaling pathway. Activated STAT proteins translocate to the cell nucleus and induce transcription of target genes, which regulate downstream cytokine production and inflammatory cell infiltration. The suppressor of cytokine signaling 1 (SOCS1 is considered as a classical inhibitor of cytokine signaling. Recent studies have demonstrated that SOCS1 expression is decreased in patients with SLE and in murine lupus models, and this negatively correlates with the magnitude of inflammation. Dysregulation of SOCS1 signals participates in various pathological processes of SLE such as hematologic abnormalities and autoantibody generation. Lupus nephritis is one of the most serious complications of SLE, and it correlates with suppressed SOCS1 signals in renal tissues. Moreover, SOCS1 insufficiency affects the function of several other organs, including skin, central nervous system, liver, and lungs. Therefore, SOCS1 aberrancy contributes to the development of both systemic and local inflammation in SLE patients. In this review, we discuss recent studies regarding the roles of SOCS1 in the pathogenesis of SLE and its therapeutic implications.

  10. Angular correlation methods

    International Nuclear Information System (INIS)

    Ferguson, A.J.

    1974-01-01

    An outline of the theory of angular correlations is presented, and the difference between the modern density matrix method and the traditional wave function method is stressed. Comments are offered on particular angular correlation theoretical techniques. A brief discussion is given of recent studies of gamma ray angular correlations of reaction products recoiling with high velocity into vacuum. Two methods for optimization to obtain the most accurate expansion coefficients of the correlation are discussed. (1 figure, 53 references) (U.S.)

  11. Processing of dual-orthogonal cw polarimetric radar signals

    NARCIS (Netherlands)

    Babur, G.

    2009-01-01

    The thesis consists of two parts. The first part is devoted to the theory of dual-orthogonal polarimetric radar signals with continuous waveforms. The thesis presents a comparison of the signal compression techniques, namely correlation and de-ramping methods, for the dual-orthogonal sophisticated

  12. On-Chip Correlator for Passive Wireless SAW Multisensor Systems

    Directory of Open Access Journals (Sweden)

    Liqiang Xie

    2016-01-01

    Full Text Available For decoding the asynchronous superposition of response signals from different sensors, it is a challenge to achieve correlation in a code division multiplexing (CDM based passive wireless surface acoustic wave (SAW multisensor system. Therefore, an on-chip correlator scheme is developed in this paper. In contrast to conventional CDM-based systems, this novel scheme enables the correlations to be operated at the SAW sensors, instead of the reader. Thus, the response signals arriving at the reader are the result of cross-correlation on the chips. It is then easy for the reader to distinguish the sensor that is matched with the interrogating signal. The operation principle, signal analysis, and simulation of the novel scheme are described in the paper. The simulation results show the response signals from the correlations of the sensors. A clear spike pulse is presented in the response signals, when a sensor code is matched with the interrogating code. Simulations verify the feasibility of the on-chip correlator concept.

  13. Correlations in Werner States

    International Nuclear Information System (INIS)

    Luo Shunlong; Li Nan

    2008-01-01

    Werner states are paradigmatic examples of quantum states and play an innovative role in quantum information theory. In investigating the correlating capability of Werner states, we find the curious phenomenon that quantum correlations, as quantified by the entanglement of formation, may exceed the total correlations, as measured by the quantum mutual information. Consequently, though the entanglement of formation is so widely used in quantifying entanglement, it cannot be interpreted as a consistent measure of quantum correlations per se if we accept the folklore that total correlations are measured (or rather upper bounded) by the quantum mutual information.

  14. Orexin/Hypocretin Signaling.

    Science.gov (United States)

    Kukkonen, Jyrki P

    Orexin/hypocretin peptide (orexin-A and orexin-B) signaling is believed to take place via the two G-protein-coupled receptors (GPCRs), named OX 1 and OX 2 orexin receptors, as described in the previous chapters. Signaling of orexin peptides has been investigated in diverse endogenously orexin receptor-expressing cells - mainly neurons but also other types of cells - and in recombinant cells expressing the receptors in a heterologous manner. Findings in the different systems are partially convergent but also indicate cellular background-specific signaling. The general picture suggests an inherently high degree of diversity in orexin receptor signaling.In the current chapter, I present orexin signaling on the cellular and molecular levels. Discussion of the connection to (potential) physiological orexin responses is only brief since these are in focus of other chapters in this book. The same goes for the post-synaptic signaling mechanisms, which are dealt with in Burdakov: Postsynaptic actions of orexin. The current chapter is organized according to the tissue type, starting from the central nervous system. Finally, receptor signaling pathways are discussed across tissues, cell types, and even species.

  15. Signal flow analysis

    CERN Document Server

    Abrahams, J R; Hiller, N

    1965-01-01

    Signal Flow Analysis provides information pertinent to the fundamental aspects of signal flow analysis. This book discusses the basic theory of signal flow graphs and shows their relation to the usual algebraic equations.Organized into seven chapters, this book begins with an overview of properties of a flow graph. This text then demonstrates how flow graphs can be applied to a wide range of electrical circuits that do not involve amplification. Other chapters deal with the parameters as well as circuit applications of transistors. This book discusses as well the variety of circuits using ther

  16. Microseism Directivity from Noise Cross-correlation

    Science.gov (United States)

    Chen, Z.; Gerstoft, P.; Bromirski, P. D.

    2015-12-01

    The direction of microseisms (0.05-0.35 Hz) is determined from noise cross-correlation with conventional pre-processing, where only earthquakes and local cultural transients (e.g. trawling, fish hitting) are removed. Noise cross-correlation has been successfully used to obtain accurate travel times, generally by retaining the phase (but not the amplitude) using one-bit or running-absolute-mean pre-processing. These methods give cross-correlation functions with modified amplitudes, and tend to accentuate long duration signals, thereby biasing the dominant source direction. Here, to avoid introducing bias, the microseism source direction in the Cascadia region was determined from cross-correlation functions for OBS data using conventional pre-processing. No significantly dominant (in the sense of total energy) microseism source directions are detected. Moreover, pelagic-generated signals tend to be weaker but have longer duration, in contrast to coastally-generated signals that tend to be stronger but have shorter duration.

  17. Purinergic signalling and diabetes

    DEFF Research Database (Denmark)

    Burnstock, Geoffrey; Novak, Ivana

    2013-01-01

    The pancreas is an organ with a central role in nutrient breakdown, nutrient sensing and release of hormones regulating whole body nutrient homeostasis. In diabetes mellitus, the balance is broken-cells can be starving in the midst of plenty. There are indications that the incidence of diabetes...... molecules in purinergic signalling cascades. This signalling takes place at the level of the pancreas, where the close apposition of various cells-endocrine, exocrine, stromal and immune cells-contributes to the integrated function. Following an introduction to diabetes, the pancreas and purinergic...... signalling, we will focus on the role of purinergic signalling and its changes associated with diabetes in the pancreas and selected tissues/organ systems affected by hyperglycaemia and other stress molecules of diabetes. Since this is the first review of this kind, a comprehensive historical angle is taken...

  18. Topological signal processing

    CERN Document Server

    Robinson, Michael

    2014-01-01

    Signal processing is the discipline of extracting information from collections of measurements. To be effective, the measurements must be organized and then filtered, detected, or transformed to expose the desired information.  Distortions caused by uncertainty, noise, and clutter degrade the performance of practical signal processing systems. In aggressively uncertain situations, the full truth about an underlying signal cannot be known.  This book develops the theory and practice of signal processing systems for these situations that extract useful, qualitative information using the mathematics of topology -- the study of spaces under continuous transformations.  Since the collection of continuous transformations is large and varied, tools which are topologically-motivated are automatically insensitive to substantial distortion. The target audience comprises practitioners as well as researchers, but the book may also be beneficial for graduate students.

  19. Transmembrane Signalling: Membrane messengers

    Science.gov (United States)

    Cockroft, Scott L.

    2017-05-01

    Life has evolved elaborate means of communicating essential chemical information across cell membranes. Inspired by biology, two new artificial mechanisms have now been developed that use synthetic messenger molecules to relay chemical signals into or across lipid membranes.

  20. Ultrahigh bandwidth signal processing

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo

    2016-01-01

    Optical time lenses have proven to be very versatile for advanced optical signal processing. Based on a controlled interplay between dispersion and phase-modulation by e.g. four-wave mixing, the processing is phase-preserving, an hence useful for all types of data signals including coherent multi......-level modulation founats. This has enabled processing of phase-modulated spectrally efficient data signals, such as orthogonal frequency division multiplexed (OFDM) signa In that case, a spectral telescope system was used, using two time lenses with different focal lengths (chirp rates), yielding a spectral...... regeneratio These operations require a broad bandwidth nonlinear platform, and novel photonic integrated nonlinear platform like aluminum gallium arsenide nano-waveguides used for 1.28 Tbaud optical signal processing will be described....

  1. Acoustic MIMO signal processing

    CERN Document Server

    Huang, Yiteng; Chen, Jingdong

    2006-01-01

    A timely and important book addressing a variety of acoustic signal processing problems under multiple-input multiple-output (MIMO) scenarios. It uniquely investigates these problems within a unified framework offering a novel and penetrating analysis.

  2. Signals and systems

    CERN Document Server

    Rao, K Deergha

    2018-01-01

    This textbook covers the fundamental theories of signals and systems analysis, while incorporating recent developments from integrated circuits technology into its examples. Starting with basic definitions in signal theory, the text explains the properties of continuous-time and discrete-time systems and their representation by differential equations and state space. From those tools, explanations for the processes of Fourier analysis, the Laplace transform, and the z-Transform provide new ways of experimenting with different kinds of time systems. The text also covers the separate classes of analog filters and their uses in signal processing applications. Intended for undergraduate electrical engineering students, chapter sections include exercise for review and practice for the systems concepts of each chapter. Along with exercises, the text includes MATLAB-based examples to allow readers to experiment with signals and systems code on their own. An online repository of the MATLAB code from this textbook can...

  3. Signal Station Inspection Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Handwritten reports resulting from detailed inspections of US Army Signal Service Stations, 1871-1889. Features reported included instrument exposure and condition,...

  4. Foundations of signal processing

    CERN Document Server

    Vetterli, Martin; Goyal, Vivek K

    2014-01-01

    This comprehensive and engaging textbook introduces the basic principles and techniques of signal processing, from the fundamental ideas of signals and systems theory to real-world applications. Students are introduced to the powerful foundations of modern signal processing, including the basic geometry of Hilbert space, the mathematics of Fourier transforms, and essentials of sampling, interpolation, approximation and compression. The authors discuss real-world issues and hurdles to using these tools, and ways of adapting them to overcome problems of finiteness and localisation, the limitations of uncertainty and computational costs. Standard engineering notation is used throughout, making mathematical examples easy for students to follow, understand and apply. It includes over 150 homework problems and over 180 worked examples, specifically designed to test and expand students' understanding of the fundamentals of signal processing, and is accompanied by extensive online materials designed to aid learning, ...

  5. Traffic Signal Cycle Lengths

    Data.gov (United States)

    Town of Chapel Hill, North Carolina — Traffic signal location list for the town of Chapel Hill. This data set includes light cycle information as well as as intersection information.The Town of Chapel...

  6. Final Technical Report for Interagency Agreement No. DE-SC0005453 “Characterizing Aerosol Distributions, Types, and Optical and Microphysical Properties using the NASA Airborne High Spectral Resolution Lidar (HSRL) and the Research Scanning Polarimeter (RSP)”

    Energy Technology Data Exchange (ETDEWEB)

    Hostetler, Chris [NASA Langley Research Center, Hampton, VA (United States); Ferrare, Richard [NASA Langley Research Center, Hampton, VA (United States)

    2015-01-13

    Measurements of the vertical profile of atmospheric aerosols and aerosol optical and microphysical characteristics are required to: 1) determine aerosol direct and indirect radiative forcing, 2) compute radiative flux and heating rate profiles, 3) assess model simulations of aerosol distributions and types, and 4) establish the ability of surface and space-based remote sensors to measure the indirect effect. Consequently the ASR program calls for a combination of remote sensing and in situ measurements to determine aerosol properties and aerosol influences on clouds and radiation. As part of our previous DOE ASP project, we deployed the NASA Langley airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 King Air aircraft during major field experiments in 2006 (MILAGRO and MaxTEX), 2007 (CHAPS), 2009 (RACORO), and 2010 (CalNex and CARES). The HSRL provided measurements of aerosol extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm). These measurements were typically made in close temporal and spatial coincidence with measurements made from DOE-funded and other participating aircraft and ground sites. On the RACORO, CARES, and CalNEX missions, we also deployed the NASA Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP). RSP provided intensity and degree of linear polarization over a broad spectral and angular range enabling column-average retrievals of aerosol optical and microphysical properties. Under this project, we analyzed observations and model results from RACORO, CARES, and CalNex and accomplished the following objectives. 1. Identified aerosol types, characterize the vertical distribution of the aerosol types, and partition aerosol optical depth by type, for CARES and CalNex using HSRL data as we have done for previous missions. 2. Investigated aerosol microphysical and macrophysical properties using the RSP. 3. Used the aerosol backscatter and extinction profiles measured by the HSRL

  7. Calibration of Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) polarization measurements, and in-flight comparisons with the Research Scanning Polarimeter (RSP) and the Spectropolarimeter for Planetary EXploration (SPEX)

    Science.gov (United States)

    van Harten, G.; Diner, D. J.; Rheingans, B. E.; Daugherty, B. J.; Xu, F.; Bull, M. A.; Tkatcheva, I. N.; Garay, M. J.; Seidel, F.; Chipman, R. A.; Smit, M.

    2016-12-01

    The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) is a remote sensing instrument for the characterization of atmospheric aerosols and clouds. AirMSPI, flying onboard the NASA ER-2 aircraft at 20 km altitude, participates in field campaigns since 2013, including ORACLES (2016). The pushbroom camera is mounted on a programmable, motorized gimbal for multi-angle observations at 10x10 m2 resolution. Eight spectral bands within 355-935 nm are recorded, 3 of which also measure linear polarization. Photoelastic modulators (PEMs) encode the polarized and total intensities in each polarimetric pixel as the amplitude and offset of a modulated intensity pattern, such that the ratio of the two is insensitive to pixel-to-pixel differences. This technique, developed to enable the high-accuracy imaging polarimetry required for aerosol species discrimination, will also be applied in the Multi-Angle Imager for Aerosols (MAIA) satellite instrument. We present the calibration and accuracy validation of AirMSPI polarization measurements. The main calibration, describing the instrument's response to any degree (DoLP) and angle of linear polarization, is performed in the lab using a recently updated, carefully designed and characterized polarization state generator (PSG-2). Validation measurements using an independent polarimeter show agreement in DoLP to within 0.001 for several DoLPs across the 0-1 range. The PEMs' retardances and phases, which are different and not necessarily stable in flight, are extracted from measurements of the on-board validator, a partially polarized light source located inside the instrument housing, which is viewed before and after each target. Although this calibration does not rely on the validator's DoLP, and the validator was not designed for DoLP calibration, the frequent measurements of its DoLP provide an upper limit for AirMSPI's in-flight polarimetric stability, which is 0.001. A correction for the actual PEM retardances and phases in the

  8. Detection and Localization of Random Signals

    DEFF Research Database (Denmark)

    Sporring, Jon; Olsen, Niels Holm; Nielsen, Mads

    2003-01-01

    Object detection and localization are common tasks in image analysis. Correlation based detection algorithms are known to work well, when dealing with objects with known geometry in Gaussianly distributed additive noise. In the Bayes’ view, correlation is linearly related to the logarithm...... filtering techniques. It is therefore interesting to extend the application to objects with many but small degrees of freedom in their geometry. These geometric variations deteriorate the linear correlation signal, both regarding its strength and localization with multiple peaks from a single object....... Localization is typically preferred over detection, and Bayesian localization may be obtained as local integration of the probability density. In this work, Gaussian kernels of the exponentiated correlation are studied, and the use of Linear Scale-Space allows us to extend the Bayes detection with a well...

  9. Redox signaling in plants.

    Science.gov (United States)

    Foyer, Christine H; Noctor, Graham

    2013-06-01

    Our aim is to deliver an authoritative and challenging perspective of current concepts in plant redox signaling, focusing particularly on the complex interface between the redox and hormone-signaling pathways that allow precise control of plant growth and defense in response to metabolic triggers and environmental constraints and cues. Plants produce significant amounts of singlet oxygen and other reactive oxygen species (ROS) as a result of photosynthetic electron transport and metabolism. Such pathways contribute to the compartment-specific redox-regulated signaling systems in plant cells that convey information to the nucleus to regulate gene expression. Like the chloroplasts and mitochondria, the apoplast-cell wall compartment makes a significant contribution to the redox signaling network, but unlike these organelles, the apoplast has a low antioxidant-buffering capacity. The respective roles of ROS, low-molecular antioxidants, redox-active proteins, and antioxidant enzymes are considered in relation to the functions of plant hormones such as salicylic acid, jasmonic acid, and auxin, in the composite control of plant growth and defense. Regulation of redox gradients between key compartments in plant cells such as those across the plasma membrane facilitates flexible and multiple faceted opportunities for redox signaling that spans the intracellular and extracellular environments. In conclusion, plants are recognized as masters of the art of redox regulation that use oxidants and antioxidants as flexible integrators of signals from metabolism and the environment.

  10. Signal processing: opportunities for superconductive circuits

    International Nuclear Information System (INIS)

    Ralston, R.W.

    1985-01-01

    Prime motivators in the evolution of increasingly sophisticated communication and detection systems are the needs for handling ever wider signal bandwidths and higher data processing speeds. These same needs drive the development of electronic device technology. Until recently the superconductive community has been tightly focused on digital devices for high speed computers. The purpose of this paper is to describe opportunities and challenges which exist for both analog and digital devices in a less familiar area, that of wideband signal processing. The function and purpose of analog signal-processing components, including matched filters, correlators and Fourier transformers, will be described and examples of superconductive implementations given. A canonic signal-processing system is then configured using these components in combination with analog/digital converters and digital output circuits to highlight the important issues of dynamic range, accuracy and equivalent computation rate. Superconductive circuits hold promise for processing signals of 10-GHz bandwidth. Signal processing systems, however, can be properly designed and implemented only through a synergistic combination of the talents of device physicists, circuit designers, algorithm architects and system engineers. An immediate challenge to the applied superconductivity community is to begin sharing ideas with these other researchers

  11. Whiteheadian approach to Bell's correlations

    International Nuclear Information System (INIS)

    Malin, S.

    1988-01-01

    Certain properties of the Bell-type correlations and, in particular, the impossibility of using them to transmit signals faster than light, are investigated from the point of view of the conceptual structure of quantum mechanics and of Whitehead's process philosophy. The collapses of quantum states are shown to correspond to perspectives of different frames of reference on a Whiteheadian process of self creation of actual entities. The analysis suggests a fundamental limitation on the capacity to describe the propagation of influences among the results of measurements at space-like separation. It is further shown that, if Whitehead's framework is modified in a specific way, it accounts very well for the apparent existence of superluminal influences, and for the impossibility of using them for superluminal communication

  12. Effective capacity of correlated MISO channels

    KAUST Repository

    Zhong, Caijun

    2011-06-01

    This paper presents an analytical performance investigation of the capacity limits of correlated multiple-input single-output (MISO) channels in the presence of quality-of-service (QoS) requirements. Exact closed-form expression for the effective capacity of correlated MISO channels is derived. In addition, simple expressions are obtained at the asymptotic high and low signal-to-noise ratio (SNR) regimes, which provide insights into the impact of various system parameters on the effective capacity of the system. Also, a complete characterization of the impact of spatial correlation on the effective capacity is provided with the aid of a majorization theory result. The findings suggest that antenna correlation reduce the effective capacity of the channels. Moreover, a stringent QoS requirement causes a significant reduction in the effective capacity but this can be effectively alleviated by increasing the number of antennas. © 2011 IEEE.

  13. Digital Signal Processing applied to Physical Signals

    CERN Document Server

    Alberto, Diego; Musa, L

    2011-01-01

    It is well known that many of the scientific and technological discoveries of the XXI century will depend on the capability of processing and understanding a huge quantity of data. With the advent of the digital era, a fully digital and automated treatment can be designed and performed. From data mining to data compression, from signal elaboration to noise reduction, a processing is essential to manage and enhance features of interest after every data acquisition (DAQ) session. In the near future, science will go towards interdisciplinary research. In this work there will be given an example of the application of signal processing to different fields of Physics from nuclear particle detectors to biomedical examinations. In Chapter 1 a brief description of the collaborations that allowed this thesis is given, together with a list of the publications co-produced by the author in these three years. The most important notations, definitions and acronyms used in the work are also provided. In Chapter 2, the last r...

  14. Intercorporate Security Event Correlation

    Directory of Open Access Journals (Sweden)

    D. O. Kovalev

    2010-03-01

    Full Text Available Security controls are prone to false positives and false negatives which can lead to unwanted reputation losses for the bank. The reputational database within the security operations center (SOC and intercorporate correlation of security events are offered as a solution to increase attack detection fidelity. The theses introduce the definition and structure of the reputation, architectures of reputational exchange and the place of intercorporate correlation in overall SOC correlation analysis.

  15. Correlation Reconstruction Tomographic PIV

    Science.gov (United States)

    La Foy, Roderick; Vlachos, Pavlos

    2017-11-01

    A new volumetric Particle Image Velocimetry technique was developed that outputs accurate velocity measurements up to very high seeding densities while requiring lower computational expenditure. This technique combines the tomographic and cross-correlation steps by directly reconstructing the 3D cross-correlation volumes. Since many particles contribute to a single correlation peak, this decreases the noise contributions from ghost reconstructions, allowing accurate velocity measurements to be made at exceptionally high seeding densities. Additionally the overall computational cost is lowered by combining the reconstruction and cross-correlation steps. Results comparing the errors of the new technique applied to both simulated and experimental data will be presented.

  16. Particle Correlations at LEP

    CERN Document Server

    Kress, Thomas

    2002-01-01

    Particle correlations are extensively studied to obtain information about the dynamics of hadron production. From 1989 to 2000 the four LEP collaborations recorded more than 16 million hadronic Z0 decays and several thousand W+W- events. In Z0 decays, two-particle correlations were analysed in detail to study Bose-Einstein and Fermi-Dirac correlations for various particle species. In fully-hadronic W+W- decays, particle correlations were used to study whether the two W bosons decay independently. A review of selected results is presented.

  17. Correlation engine prototype

    CERN Document Server

    Pose, V

    2003-01-01

    The CERN monitoring prototype, part of the fabric management work package (WP4) of the DataGrid project, task Monitoring, collects monitoring data from farm nodes in CERN into a central monitoring database. Performing correlations on the data in the monitoring database should help to foresee exceptions on individual nodes or node groups and to analyze performance of the farm. The Correlation Engine Prototype has been developed to provide easy adding of new correlations of monitoring data and actions triggered in case of exceptions. The current prototype is written in Perl. The results of the correlation engine can be accessed through a web-interface.

  18. Correlated Electromagnetic Levitation Actuator

    Data.gov (United States)

    National Aeronautics and Space Administration — Approach is to first characterize the capabilities of correlated electromagnets by developing a prototype with readily available materials and manufacturing...

  19. Dual template optical correlator for pattern recognition

    Science.gov (United States)

    Chin, Freddie Y. H.; Somekh, Michael G.; Valera, M. S.; Crowe, John A.

    1992-08-01

    A new coherent optical correlator system has been developed for intended application to breast cancer screening. Such a system must have an inherent capability to deal with patterns that have high degrees of similarity between the desired and rejected classes, due to the overall similarity between benign and malignant cells. Consequently, effort has been directed toward achieving this goal. This paper presents an optical configuration that contains two coherent optical processors (COPs) working in parallel and utilizes phase-stepping detection at the output to multiply the two correlation signals. It is shown how this scheme offers an excellent compromise between good discrimination and immunity from noise added in the input plane

  20. Quantitative measurement of intervertebral disc signal using MRI

    Energy Technology Data Exchange (ETDEWEB)

    Niemelaeinen, R. [Faculty of Rehabilitation Medicine, University of Alberta, Edmonton (Canada)], E-mail: riikka.niemelainen@ualberta.ca; Videman, T. [Faculty of Rehabilitation Medicine, University of Alberta, Edmonton (Canada); Dhillon, S.S. [Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton (Canada); Battie, M.C. [Faculty of Rehabilitation Medicine, University of Alberta, Edmonton (Canada)

    2008-03-15

    Aim: To investigate the spinal cord as an alternative intra-body reference to cerebrospinal fluid (CSF) in evaluating thoracic disc signal intensity. Materials and methods: T2-weighted magnetic resonance imaging (MRI) images of T6-T12 were obtained using 1.5 T machines for a population-based sample of 523 men aged 35-70 years. Quantitative data on the signal intensities were acquired using an image analysis program (SpEx (copy right) ). A random sample of 30 subjects and intraclass correlation coeffcients (ICC) were used to examine the repeatability of the spinal cord measurements. The validity of using the spinal cord as a reference was examined by correlating cord and CSF samples. Finally, thoracic disc signal was validated by correlating it with age without adjustment and adjusting for either cord or CSF. Pearson's r was used for correlational analyses. Results: The repeatability of the spinal cord signal measurements was extremely high ({>=}0.99). The correlations between the signals of spinal cord and CSF by level were all above 0.9. The spinal cord-adjusted disc signal and age correlated similarly with CSF-adjusted disc signal and age (r = -0.30 to -0.40 versus r = -0.26 to -0.36). Conclusion: Adjacent spinal cord is a good alternative reference to the current reference standard, CSF, for quantitative measurements of disc signal intensity. Clearly fewer levels were excluded when using spinal cord as compared to CSF due to missing reference samples.

  1. Cellular signalling properties in microcircuits

    DEFF Research Database (Denmark)

    Toledo-Rodriguez, Maria; El Manira, Abdeljabbar; Wallén, Peter

    2005-01-01

    Molecules and cells are the signalling elements in microcircuits. Recent studies have uncovered bewildering diversity in postsynaptic signalling properties in all areas of the vertebrate nervous system. Major effort is now being invested in establishing the specialized signalling properties...

  2. Financial signal processing and machine learning

    CERN Document Server

    Kulkarni,Sanjeev R; Dmitry M. Malioutov

    2016-01-01

    The modern financial industry has been required to deal with large and diverse portfolios in a variety of asset classes often with limited market data available. Financial Signal Processing and Machine Learning unifies a number of recent advances made in signal processing and machine learning for the design and management of investment portfolios and financial engineering. This book bridges the gap between these disciplines, offering the latest information on key topics including characterizing statistical dependence and correlation in high dimensions, constructing effective and robust risk measures, and their use in portfolio optimization and rebalancing. The book focuses on signal processing approaches to model return, momentum, and mean reversion, addressing theoretical and implementation aspects. It highlights the connections between portfolio theory, sparse learning and compressed sensing, sparse eigen-portfolios, robust optimization, non-Gaussian data-driven risk measures, graphical models, causal analy...

  3. Signal processing for distributed readout using TESs

    International Nuclear Information System (INIS)

    Smith, Stephen J.; Whitford, Chris H.; Fraser, George W.

    2006-01-01

    We describe optimal filtering algorithms for determining energy and position resolution in position-sensitive Transition Edge Sensor (TES) Distributed Read-Out Imaging Devices (DROIDs). Improved algorithms, developed using a small-signal finite-element model, are based on least-squares minimisation of the total noise power in the correlated dual TES DROID. Through numerical simulations we show that significant improvements in energy and position resolution are theoretically possible over existing methods

  4. Array enhanced stochastic resonance and spatially correlated noises

    OpenAIRE

    Gora, P. F.

    2003-01-01

    We discuss the role of spatial correlations of the noise in the array enhanced stochastic resonance. We show numerically that the noises with negative correlations between different sites lead to significantly larger values of the signal-to-noise ratio than the uncorrelated noises or noises with positive correlations. If the noise is global, the system displays only the conventional stochastic resonance, without any array enhancement.

  5. VLSI signal processing technology

    CERN Document Server

    Swartzlander, Earl

    1994-01-01

    This book is the first in a set of forthcoming books focussed on state-of-the-art development in the VLSI Signal Processing area. It is a response to the tremendous research activities taking place in that field. These activities have been driven by two factors: the dramatic increase in demand for high speed signal processing, especially in consumer elec­ tronics, and the evolving microelectronic technologies. The available technology has always been one of the main factors in determining al­ gorithms, architectures, and design strategies to be followed. With every new technology, signal processing systems go through many changes in concepts, design methods, and implementation. The goal of this book is to introduce the reader to the main features of VLSI Signal Processing and the ongoing developments in this area. The focus of this book is on: • Current developments in Digital Signal Processing (DSP) pro­ cessors and architectures - several examples and case studies of existing DSP chips are discussed in...

  6. Correlates of Academic Procrastination.

    Science.gov (United States)

    Milgram, Norman A.; And Others

    1993-01-01

    Investigated concurrent correlates of academic procrastination in Israeli college preparatory students (n=113). Procrastination in one course of study was found to be moderately correlated with procrastination in another but not to procrastination in routine tasks of daily living. Procrastination was weakly related to emotional upset about it and…

  7. Quantum correlation games

    International Nuclear Information System (INIS)

    Iqbal, Azhar; Weigert, Stefan

    2004-01-01

    A new approach to play games quantum mechanically is proposed. We consider two players who perform measurements in an EPR-type setting. The payoff relations are defined as functions of correlations, i.e. without reference to classical or quantum mechanics. Classical bi-matrix games are reproduced if the input states are classical and perfectly anti-correlated, that is, for a classical correlation game. However, for a quantum correlation game, with an entangled singlet state as input, qualitatively different solutions are obtained. For example, the Prisoners' Dilemma acquires a Nash equilibrium if both players apply a mixed strategy. It appears to be conceptually impossible to reproduce the properties of quantum correlation games within the framework of classical games

  8. Quantum correlation games

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Azhar; Weigert, Stefan [HuMP-Hull Mathematical Physics, Department of Mathematics, University of Hull (United Kingdom)

    2004-06-04

    A new approach to play games quantum mechanically is proposed. We consider two players who perform measurements in an EPR-type setting. The payoff relations are defined as functions of correlations, i.e. without reference to classical or quantum mechanics. Classical bi-matrix games are reproduced if the input states are classical and perfectly anti-correlated, that is, for a classical correlation game. However, for a quantum correlation game, with an entangled singlet state as input, qualitatively different solutions are obtained. For example, the Prisoners' Dilemma acquires a Nash equilibrium if both players apply a mixed strategy. It appears to be conceptually impossible to reproduce the properties of quantum correlation games within the framework of classical games.

  9. Meson Correlators in Finite Temperature Lattice QCD

    CERN Document Server

    De Forcrand, Philippe; Hashimoto, T; Hioki, S; Matsufuru, H; Miyamura, O; Nakamura, A; Takaishi, T; Umeda, T; Stamatescu, I O; CERN. Geneva; Forcrand, Ph. de

    2001-01-01

    We analyze temporal and spatial meson correlators in quenched lattice QCD at T>0. Below T_c we observe little change in the meson properties as compared with T=0. Above T_c we observe new features: chiral symmetry restoration and signals of plasma formation, but also indication of persisting mesonic (metastable) states and different temporal and spatial masses in the mesonic channels. This suggests a complex picture of QGP in the region 1 - 1.5 T_c.

  10. Visible light optical coherence correlation spectroscopy.

    Science.gov (United States)

    Broillet, Stephane; Szlag, Daniel; Bouwens, Arno; Maurizi, Lionel; Hofmann, Heinrich; Lasser, Theo; Leutenegger, Marcel

    2014-09-08

    Optical coherence correlation spectroscopy (OCCS) allows studying kinetic processes at the single particle level using the backscattered light of nanoparticles. We extend the possibilities of this technique by increasing its signal-to-noise ratio by a factor of more than 25 and by generalizing the method to solutions containing multiple nanoparticle species. We applied these improvements by measuring protein adsorption and formation of a protein monolayer on superparamagnetic iron oxide nanoparticles under physiological conditions.

  11. Honest signalling with costly gambles.

    Science.gov (United States)

    Meacham, Frazer; Perlmutter, Aaron; Bergstrom, Carl T

    2013-10-06

    Costly signalling theory is commonly invoked as an explanation for how honest communication can be stable when interests conflict. However, the signal costs predicted by costly signalling models often turn out to be unrealistically high. These models generally assume that signal cost is determinate. Here, we consider the case where signal cost is instead stochastic. We examine both discrete and continuous signalling games and show that, under reasonable assumptions, stochasticity in signal costs can decrease the average cost at equilibrium for all individuals. This effect of stochasticity for decreasing signal costs is a fundamental mechanism that probably acts in a wide variety of circumstances.

  12. Non-signaling boxes and quantum logics

    International Nuclear Information System (INIS)

    Tylec, T I; Kuś, M

    2015-01-01

    Using a quantum logic approach we analyze the structure of the so-called non-signaling theories respecting relativistic causality, but allowing correlations violating bounds imposed by quantum mechanics such as CHSH inequality. We discuss the relations among such theories, quantum mechanics, and classical physics. Our main result is the construction of a probability theory adequate for the simplest instance of a non-signaling theory—the two non-signaling boxes world—in which we exhibit its differences in comparison with classical and quantum probabilities. We show that the question of whether such a theory can be treated as a kind of ‘generalization’ of the quantum theory of the two-qubit system cannot be answered positively. Some of its features put it closer to the quantum world—on the one hand, for example, the measurements are destructive, though on the other hand the Heisenberg uncertainty relations are not satisfied. Another interesting property contrasting it from quantum mechanics is that the subset of ‘classically correlated states’, i.e. the states with only classical correlations, does not reproduce the classical world of the two two-state systems. Our results establish a new link between quantum information theory and the well-developed theory of quantum logics. (paper)

  13. Simultaneous multichannel signal transfers via chaos in a recurrent neural network.

    Science.gov (United States)

    Soma, Ken-ichiro; Mori, Ryota; Sato, Ryuichi; Furumai, Noriyuki; Nara, Shigetoshi

    2015-05-01

    We propose neural network model that demonstrates the phenomenon of signal transfer between separated neuron groups via other chaotic neurons that show no apparent correlations with the input signal. The model is a recurrent neural network in which it is supposed that synchronous behavior between small groups of input and output neurons has been learned as fragments of high-dimensional memory patterns, and depletion of neural connections results in chaotic wandering dynamics. Computer experiments show that when a strong oscillatory signal is applied to an input group in the chaotic regime, the signal is successfully transferred to the corresponding output group, although no correlation is observed between the input signal and the intermediary neurons. Signal transfer is also observed when multiple signals are applied simultaneously to separate input groups belonging to different memory attractors. In this sense simultaneous multichannel communications are realized, and the chaotic neural dynamics acts as a signal transfer medium in which the signal appears to be hidden.

  14. Quantum signaling game

    International Nuclear Information System (INIS)

    Frackiewicz, Piotr

    2014-01-01

    We present a quantum approach to a signaling game; a special kind of extensive game of incomplete information. Our model is based on quantum schemes for games in strategic form where players perform unitary operators on their own qubits of some fixed initial state and the payoff function is given by a measurement on the resulting final state. We show that the quantum game induced by our scheme coincides with a signaling game as a special case and outputs nonclassical results in general. As an example, we consider a quantum extension of the signaling game in which the chance move is a three-parameter unitary operator whereas the players' actions are equivalent to classical ones. In this case, we study the game in terms of Nash equilibria and refine the pure Nash equilibria adapting to the quantum game the notion of a weak perfect Bayesian equilibrium. (paper)

  15. PKD signaling and pancreatitis

    Science.gov (United States)

    Yuan, Jingzhen; Pandol, Stephen J.

    2016-01-01

    Background Acute pancreatitis is a serious medical disorder with no current therapies directed to the molecular pathogenesis of the disorder. Inflammation, inappropriate intracellular activation of digestive enzymes, and parenchymal acinar cell death by necrosis are the critical pathophysiologic processes of acute pancreatitis. Thus, it is necessary to elucidate the key molecular signals that mediate these pathobiologic processes and develop new therapeutic strategies to attenuate the appropriate signaling pathways in order to improve outcomes for this disease. A novel serine/threonine protein kinase D (PKD) family has emerged as key participants in signal transduction, and this family is increasingly being implicated in the regulation of multiple cellular functions and diseases. Methods This review summarizes recent findings of our group and others regarding the signaling pathway and the biological roles of the PKD family in pancreatic acinar cells. In particular, we highlight our studies of the functions of PKD in several key pathobiologic processes associated with acute pancreatitis in experimental models. Results Our findings reveal that PKD signaling is required for NF-κB activation/inflammation, intracellular zymogen activation, and acinar cell necrosis in rodent experimental pancreatitis. Novel small-molecule PKD inhibitors attenuate the severity of pancreatitis in both in vitro and in vivo experimental models. Further, this review emphasizes our latest advances in the therapeutic application of PKD inhibitors to experimental pancreatitis after the initiation of pancreatitis. Conclusions These novel findings suggest that PKD signaling is a necessary modulator in key initiating pathobiologic processes of pancreatitis, and that it constitutes a novel therapeutic target for treatments of this disorder. PMID:26879861

  16. Electronic signal conditioning

    CERN Document Server

    NEWBY, BRUCE

    1994-01-01

    At technician level, brief references to signal conditioning crop up in a fragmented way in various textbooks, but there has been no single textbook, until now!More advanced texts do exist but they are more mathematical and presuppose a higher level of understanding of electronics and statistics. Electronic Signal Conditioning is designed for HNC/D students and City & Guilds Electronics Servicing 2240 Parts 2 & 3. It will also be useful for BTEC National, Advanced GNVQ, A-level electronics and introductory courses at degree level.

  17. Purinergic Signalling: Therapeutic Developments

    OpenAIRE

    Burnstock, Geoffrey

    2017-01-01

    Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990’s when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine) receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and ...

  18. Genomic signal processing

    CERN Document Server

    Shmulevich, Ilya

    2007-01-01

    Genomic signal processing (GSP) can be defined as the analysis, processing, and use of genomic signals to gain biological knowledge, and the translation of that knowledge into systems-based applications that can be used to diagnose and treat genetic diseases. Situated at the crossroads of engineering, biology, mathematics, statistics, and computer science, GSP requires the development of both nonlinear dynamical models that adequately represent genomic regulation, and diagnostic and therapeutic tools based on these models. This book facilitates these developments by providing rigorous mathema

  19. TOR signalling in plants.

    Science.gov (United States)

    Rexin, Daniel; Meyer, Christian; Robaglia, Christophe; Veit, Bruce

    2015-08-15

    Although the eukaryotic TOR (target of rapamycin) kinase signalling pathway has emerged as a key player for integrating nutrient-, energy- and stress-related cues with growth and metabolic outputs, relatively little is known of how this ancient regulatory mechanism has been adapted in higher plants. Drawing comparisons with the substantial knowledge base around TOR kinase signalling in fungal and animal systems, functional aspects of this pathway in plants are reviewed. Both conserved and divergent elements are discussed in relation to unique aspects associated with an autotrophic mode of nutrition and adaptive strategies for multicellular development exhibited by plants. © 2015 Authors; published by Portland Press Limited.

  20. Flash signal evolution in Photinus fireflies: character displacement and signal exploitation in a visual communication system.

    Science.gov (United States)

    Stanger-Hall, Kathrin F; Lloyd, James E

    2015-03-01

    Animal communication is an intriguing topic in evolutionary biology. In this comprehensive study of visual signal evolution, we used a phylogenetic approach to study the evolution of the flash communication system of North American fireflies. The North American firefly genus Photinus contains 35 described species with simple ON-OFF visual signals, and information on habitat types, sympatric congeners, and predators. This makes them an ideal study system to test hypotheses on the evolution of male and female visual signal traits. Our analysis of 34 Photinus species suggests two temporal pattern generators: one for flash duration and one for flash intervals. Reproductive character displacement was a main factor for signal divergence in male flash duration among sympatric Photinus species. Male flash pattern intervals (i.e., the duration of the dark periods between signals) were positively correlated with the number of sympatric Photuris fireflies, which include predators of Photinus. Females of different Photinus species differ in their response preferences to male traits. As in other communication systems, firefly male sexual signals seem to be a compromise between optimizing mating success (sexual selection) and minimizing predation risk (natural selection). An integrative model for Photinus signal evolution is proposed. © 2015 The Author(s).