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Sample records for rotational correlation time

  1. Rotationally invariant correlation filtering

    International Nuclear Information System (INIS)

    Schils, G.F.; Sweeney, D.W.

    1985-01-01

    A method is presented for analyzing and designing optical correlation filters that have tailored rotational invariance properties. The concept of a correlation of an image with a rotation of itself is introduced. A unified theory of rotation-invariant filtering is then formulated. The unified approach describes matched filters (with no rotation invariance) and circular-harmonic filters (with full rotation invariance) as special cases. The continuum of intermediate cases is described in terms of a cyclic convolution operation over angle. The angular filtering approach allows an exact choice for the continuous trade-off between loss of the correlation energy (or specificity regarding the image) and the amount of rotational invariance desired

  2. Statistical model of exotic rotational correlations in emergent space-time

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Craig; Kwon, Ohkyung; Richardson, Jonathan

    2017-06-06

    A statistical model is formulated to compute exotic rotational correlations that arise as inertial frames and causal structure emerge on large scales from entangled Planck scale quantum systems. Noncommutative quantum dynamics are represented by random transverse displacements that respect causal symmetry. Entanglement is represented by covariance of these displacements in Planck scale intervals defined by future null cones of events on an observer's world line. Light that propagates in a nonradial direction inherits a projected component of the exotic rotational correlation that accumulates as a random walk in phase. A calculation of the projection and accumulation leads to exact predictions for statistical properties of exotic Planck scale correlations in an interferometer of any configuration. The cross-covariance for two nearly co-located interferometers is shown to depart only slightly from the autocovariance. Specific examples are computed for configurations that approximate realistic experiments, and show that the model can be rigorously tested.

  3. Counterclockwise and Clockwise Rotation of QRS Transitional Zone: Prospective Correlates of Change and Time-Varying Associations With Cardiovascular Outcomes.

    Science.gov (United States)

    Patel, Siddharth; Kwak, Lucia; Agarwal, Sunil K; Tereshchenko, Larisa G; Coresh, Josef; Soliman, Elsayed Z; Matsushita, Kunihiro

    2017-11-03

    A few studies have recently reported clockwise and counterclockwise rotations of QRS transition zone as predictors of mortality. However, their prospective correlates and associations with individual cardiovascular disease (CVD) outcomes are yet to be investigated. Among 13 567 ARIC (Atherosclerosis Risk in Communities) study participants aged 45 to 64 years, we studied key correlates of changes in the status of clockwise and counterclockwise rotation over time as well as the association of rotation status with incidence of coronary heart disease (2408 events), heart failure (2196 events), stroke (991 events), composite CVD (4124 events), 898 CVD deaths, and 3469 non-CVD deaths over 23 years of follow-up. At baseline, counterclockwise rotation was most prevalent (52.9%), followed by no (40.5%) and clockwise (6.6%) rotation. Of patients with no rotation, 57.9% experienced counterclockwise or clockwise rotation during follow-up, with diabetes mellitus and black race significantly predicting clockwise and counterclockwise conversion, respectively. Clockwise rotation was significantly associated with higher risk of heart failure (hazard ratio, 1.20; 95% confidence interval [CI], 1.02-1.41) and non-CVD death (hazard ratio, 1.28; 95% CI, 1.12-1.46) after adjusting for potential confounders including other ECG parameters. On the contrary, counterclockwise rotation was significantly related to lower risk of composite CVD (hazard ratio, 0.93; 95% CI, 0.87-0.99]), CVD mortality (hazard ratio, 0.76; 95% CI, 0.65-0.88), and non-CVD deaths (hazard ratio, 0.92; 95% CI, 0.85-0.99 [borderline significance with heart failure]). Counterclockwise rotation, the most prevalent QRS transition zone pattern, demonstrated the lowest risk of CVD and mortality, whereas clockwise rotation was associated with the highest risk of heart failure and non-CVD mortality. These results have implications on how to interpret QRS transition zone rotation when ECG was recorded. © 2017 The Authors

  4. Optimization of multi-slice helical respiration-correlated CT: the effects of table speed and rotation time

    International Nuclear Information System (INIS)

    Wink, Nicole M; McNitt-Gray, Michael F; Solberg, Timothy D

    2005-01-01

    While respiration-correlated CT is gaining acceptance in clinical radiotherapy, the effect of scanning parameters on the image quality has yet to be addressed. The intent of this study was to characterize the effects of gantry rotation and table speed on various image quality characteristics in multi-slice, helical, retrospectively-gated CT images. Images of stationary and moving phantoms were obtained in helical mode on a 20-slice CT scanner. Motion was generated by a computer-controlled platform capable of moving simultaneously in two dimensions. Motion was monitored using a pressure gauge inserted inside an adjustable belt. Selected scans were retrospectively gated into ten phases based on the monitored motion. Gantry rotation speeds of 0.5 s and 1.0 s were evaluated with pitches ranging from 0.1 to 0.45. Several parameters, including calculated object volumes, trajectory (movement from peak to trough), deformation (actual volume divided by volume created with the maximum diameter of contoured object) and z-axis resolution, were used to characterize image quality. These studies indicate that for objects in the peak phase of a movement pattern that simulates breathing, retrospectively gated scans using fast gantry rotation speeds produce volume, trajectory, deformation and z-axis resolution results comparable with those of a stationary object

  5. Learning Rotation for Kernel Correlation Filter

    KAUST Repository

    Hamdi, Abdullah; Ghanem, Bernard

    2017-01-01

    . This paper tries to tackle the problem of rotation by reformulating the optimization problem for learning the correlation filter. This modification (RKCF) includes learning rotation filter that utilizes circulant structure of HOG feature to guesstimate

  6. Learning Rotation for Kernel Correlation Filter

    KAUST Repository

    Hamdi, Abdullah

    2017-08-11

    Kernel Correlation Filters have shown a very promising scheme for visual tracking in terms of speed and accuracy on several benchmarks. However it suffers from problems that affect its performance like occlusion, rotation and scale change. This paper tries to tackle the problem of rotation by reformulating the optimization problem for learning the correlation filter. This modification (RKCF) includes learning rotation filter that utilizes circulant structure of HOG feature to guesstimate rotation from one frame to another and enhance the detection of KCF. Hence it gains boost in overall accuracy in many of OBT50 detest videos with minimal additional computation.

  7. Exotic rotational correlations in quantum geometry

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Craig

    2017-05-01

    It is argued by extrapolation of general relativity and quantum mechanics that a classical inertial frame corresponds to a statistically defined observable that rotationally fluctuates due to Planck scale indeterminacy. Physical effects of exotic nonlocal rotational correlations on large scale field states are estimated. Their entanglement with the strong interaction vacuum is estimated to produce a universal, statistical centrifugal acceleration that resembles the observed cosmological constant.

  8. Dynamical pairing correlations in rotating nuclei

    International Nuclear Information System (INIS)

    Szymanski, Z.

    1985-01-01

    When the atomic nucleus rotates fast enough the static pair correlations may be destroyed. In this situation the pair-vibrations become an important manifestation of the short-range attractive pairing force. The influence of this effect on nuclear properties at high spin is discussed. (orig.)

  9. Temperature dependent heterogeneous rotational correlation in lipids.

    Science.gov (United States)

    Dadashvand, Neda; Othon, Christina M

    2016-11-15

    Lipid structures exhibit complex and highly dynamic lateral structure; and changes in lipid density and fluidity are believed to play an essential role in membrane targeting and function. The dynamic structure of liquids on the molecular scale can exhibit complex transient density fluctuations. Here the lateral heterogeneity of lipid dynamics is explored in free standing lipid monolayers. As the temperature is lowered the probes exhibit increasingly broad and heterogeneous rotational correlation. This increase in heterogeneity appears to exhibit a critical onset, similar to those observed for glass forming fluids. We explore heterogeneous relaxation in in a single constituent lipid monolayer of 1, 2-dimyristoyl-sn-glycero-3-phosphocholine  by measuring the rotational diffusion of a fluorescent probe (1-palmitoyl-2-[1]-sn-glycero-3-phosphocholine), which is embedded in the lipid monolayer at low labeling density. Dynamic distributions are measured using wide-field time-resolved fluorescence anisotropy. The observed relaxation exhibits a narrow, liquid-like distribution at high temperatures (τ ∼ 2.4 ns), consistent with previous experimental measures (Dadashvand et al 2014 Struct. Dyn. 1 054701, Loura and Ramalho 2007 Biochim. Biophys. Acta 1768 467-478). However, as the temperature is quenched, the distribution broadens, and we observe the appearance of a long relaxation population (τ ∼ 16.5 ns). This supports the heterogeneity observed for lipids at high packing densities, and demonstrates that the nanoscale diffusion and reorganization in lipid structures can be significantly complex, even in the simplest amorphous architectures. Dynamical heterogeneity of this form can have a significant impact on the organization, permeability and energetics of lipid membrane structures.

  10. Energy correlations for mixed rotational bands

    International Nuclear Information System (INIS)

    Doessing, T.

    1985-01-01

    A schematic model for the mixing of rotational bands above the yrast line in well deformed nuclei is considered. Many-particle configurations of a rotating mean field form basis bands, and these are subsequently mixed due to a two body residual interaction. The energy interval over which a basis band is spread out increases with increasing excitation energy above the yrast line. Conversely, the B(E2) matrix element for rotational decay out of one of the mixed band states is spread over an interval which is predicted to become more narrow with increasing excitation energy. Finally, the implication of band mixing for γ-ray energy correlations is briefly discussed. (orig.)

  11. Vector correlations in rotationally inelastic molecular collisions

    International Nuclear Information System (INIS)

    Lemeshko, Mikhail

    2011-01-01

    The thesis presents an analytic model that describes scalar and vector properties of molecular collisions, both field-free and in fields. The model is based on the sudden approximation and treats molecular scattering as the Fraunhofer diffraction of matter waves from the hard-core part of the interaction potential. The theory has no fitting parameters and is inherently quantum, rendering fully state- and energy-resolved scattering amplitudes and all the quantities that unfold from them in analytic form. This allows to obtain complex polarization moments inherent to quantum stereodynamics, and to account for interference and other non-classical effects. The simplicity and analyticity of the model paves a way to understanding the origin of the features observed in experiment and exact computations, such as the angular oscillations in the state-to-state differential cross sections and the polarization moments, the rotational-state dependent variation of the integral cross sections, and change of these quantities as a function of the applied field. The theory was applied to study the k - k ' vector correlation (differential cross section) for the following collision systems: Ar-NO(X 2 Π) and Ne-OCS(X 1 Σ) in an electrostatic field, Na + -N 2 (X 1 Σ) in a laser field, and He-CaH( 2 Σ), He-O 2 (X 3 Σ), and He-OH(X 2 Π) in a magnetic field. The model was able to reproduce the behavior of the differential cross sections and their variation with field strength. Combining the Fraunhofer model with the quantum theory of vector correlations made it possible to study three- and four-vector properties. The model results for the k-k ' -j ' vector correlation in Ar-NO(X 2 Π) and He-NO(X 2 Π) scattering were found to be in good agreement with experiment and exact computations. This allowed to demonstrate that the stereodynamics of such collisions is contained solely in the diffractive part of the scattering amplitude which is governed by a single Legendre moment

  12. Vector correlations in rotationally inelastic molecular collisions

    Energy Technology Data Exchange (ETDEWEB)

    Lemeshko, Mikhail

    2011-04-13

    The thesis presents an analytic model that describes scalar and vector properties of molecular collisions, both field-free and in fields. The model is based on the sudden approximation and treats molecular scattering as the Fraunhofer diffraction of matter waves from the hard-core part of the interaction potential. The theory has no fitting parameters and is inherently quantum, rendering fully state- and energy-resolved scattering amplitudes and all the quantities that unfold from them in analytic form. This allows to obtain complex polarization moments inherent to quantum stereodynamics, and to account for interference and other non-classical effects. The simplicity and analyticity of the model paves a way to understanding the origin of the features observed in experiment and exact computations, such as the angular oscillations in the state-to-state differential cross sections and the polarization moments, the rotational-state dependent variation of the integral cross sections, and change of these quantities as a function of the applied field. The theory was applied to study the k - k{sup '} vector correlation (differential cross section) for the following collision systems: Ar-NO(X{sup 2}{pi}) and Ne-OCS(X{sup 1}{sigma}) in an electrostatic field, Na{sup +}-N{sub 2}(X{sup 1}{sigma}) in a laser field, and He-CaH({sup 2}{sigma}), He-O{sub 2}(X{sup 3}{sigma}), and He-OH(X{sup 2}{pi}) in a magnetic field. The model was able to reproduce the behavior of the differential cross sections and their variation with field strength. Combining the Fraunhofer model with the quantum theory of vector correlations made it possible to study three- and four-vector properties. The model results for the k-k{sup '}-j{sup '} vector correlation in Ar-NO(X{sup 2}{pi}) and He-NO(X{sup 2}{pi}) scattering were found to be in good agreement with experiment and exact computations. This allowed to demonstrate that the stereodynamics of such collisions is contained solely in the

  13. Time-dependent, Bianchi II, rotating universe

    International Nuclear Information System (INIS)

    Reboucas, M.J.

    1981-01-01

    An exact cosmological solution of Einstein's equations which has time-dependent rotation is presented. The t-constant sections are of Bianchi type II. The source of this geometry is a fluid which has not been thermalized. (Author) [pt

  14. Experimental use of iteratively designed rotation invariant correlation filters

    International Nuclear Information System (INIS)

    Sweeney, D.W.; Ochoa, E.; Schils, G.F.

    1987-01-01

    Iteratively designed filters are incorporated into an optical correlator for position, rotation, and intensity invariant recognition of target images. The filters exhibit excellent discrimination because they are designed to contain full information about the target image. Numerical simulations and experiments demonstrate detection of targets that are corrupted with random noise (SNR≅0.5) and also partially obscured by other objects. The complex valued filters are encoded in a computer generated hologram and fabricated directly using an electron-beam system. Experimental results using a liquid crystal spatial light modulator for real-time input show excellent agreement with analytical and numerical computations

  15. Ultrasound of the rotator cuff with MRI and anatomic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Rutten, Matthieu J.C.M. [Department of Radiology, Jeroen Bosch Hospital, Nieuwstraat 34, 5211 NL ' s-Hertogenbosch (Netherlands)]. E-mail: M.Rutten@JBZ.nl; Maresch, Bas J. [Department of Radiology, Hospital Gelderse Vallei, Willy Brandtlaan 10, 6710 HN Ede (Netherlands)]. E-mail: MareschB@zgv.nl; Jager, Gerrit J. [Department of Radiology, Jeroen Bosch Hospital, Nieuwstraat 34, 5211 NL ' s-Hertogenbosch (Netherlands)]. E-mail: G.Jager@JBZ.nl; Blickman, Johan G. [Department of Radiology, University Medical Center Nijmegen, Geert Grooteplein Zuid 18, 6500 HB Nijmegen (Netherlands)]. E-mail: J.Blickman@rad.umcn.nl; Holsbeeck, Marnix T. van [Department of Radiology, Henry Ford Hospital, 2799 W Grand Boulevard, Detroit, MI 48202 (United States)]. E-mail: vanholsbeeck@comcast.net

    2007-06-15

    Magnetic resonance imaging and high-resolution ultrasound (US) are frequently used for the detection of rotator cuff tears. The diagnostic yield of US is influenced by several factors as technique, knowledge of the imaging characteristics of anatomic and pathologic findings and of pitfalls. The purpose of this article is to illustrates that the standardized high-resolution US examination of the shoulder covers the entire rotator cuff and correlates with MR imaging and anatomic sections.

  16. Pair correlation of super-deformed rotation band

    International Nuclear Information System (INIS)

    Shimizu, Yoshio

    1989-01-01

    The effect of pair correlation, one of the most important residual interactions associated with the super-deformed rotation band, is discussed in terms of the characteristics of the rotation band (its effect on the moment of inertia in particular), and the tunneling into an normal deformed state in relation to its effect on the angular momentum dependence of the potential energy plane as a function of the deformation. The characteristics of the rotation band is discussed in terms of the kinematic and dynamic momenta of inertia. It is shown that the pair correlation in a super-deformed rotation band acts to decrease the former and increase the latter momentum mainly due to dynamic pair correlation. A theoretical approach that takes this effect into account can provide results that are consistent with measured momenta, although large differences can occur in some cases. Major conflicts include a large measured kinetic momentum of inertia compared to the theoretical value, and the absence of the abnormality (shape increase) generally seen in low-spin experiments. The former seems likely to be associated with the method of measuring the angular momentum. (N.K.)

  17. Rotational Invariance of the 2d Spin - Spin Correlation Function

    Science.gov (United States)

    Pinson, Haru

    2012-09-01

    At the critical temperature in the 2d Ising model on the square lattice, we establish the rotational invariance of the spin-spin correlation function using the asymptotics of the spin-spin correlation function along special directions (McCoy and Wu in the two dimensional Ising model. Harvard University Press, Cambridge, 1973) and the finite difference Hirota equation for which the spin-spin correlation function is shown to satisfy (Perk in Phys Lett A 79:3-5, 1980; Perk in Proceedings of III international symposium on selected topics in statistical mechanics, Dubna, August 22-26, 1984, JINR, vol II, pp 138-151, 1985).

  18. Fluctuations and correlations in rotating Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Baharian, Soheil; Baym, Gordon

    2010-01-01

    We investigate the effects of correlations on the properties of the ground state of the rotating harmonically trapped Bose gas by adding Bogoliubov fluctuations to the mean-field ground state of an N-particle single-vortex system. We demonstrate that the fluctuation-induced correlations lower the energy compared to that of the mean-field ground state, that the vortex core is pushed slightly away from the center of the trap, and that an unstable mode with negative energy (for rotations slower than a critical frequency) emerges in the energy spectrum, thus pointing to a better state for slow rotation. We construct mean-field ground states of zero-, one-, and two-vortex states as a function of rotation rate and determine the critical frequencies for transitions between these states, as well as the critical frequency for appearance of a metastable state with an off-center vortex and its image vortex in the evanescent tail of the cloud.

  19. M Dwarf Rotation from the K2 Young Clusters to the Field. I. A Mass-Rotation Correlation at 10 Myr

    Science.gov (United States)

    Somers, Garrett; Stauffer, John; Rebull, Luisa; Cody, Ann Marie; Pinsonneault, Marc

    2017-12-01

    Recent observations of the low-mass (0.1-0.6 {M}⊙ ) rotation distributions of the Pleiades and Praesepe clusters have revealed a ubiquitous correlation between mass and rotation, such that late M dwarfs rotate an order-of-magnitude faster than early M dwarfs. In this paper, we demonstrate that this mass-rotation correlation is present in the 10 Myr Upper Scorpius association, as revealed by new K2 rotation measurements. Using rotational evolution models, we show that the low-mass rotation distribution of the 125 Myr Pleiades cluster can only be produced if it hosted an equally strong mass-rotation correlation at 10 Myr. This suggests that physical processes important in the early pre-main sequence (PMS; star formation, accretion, disk-locking) are primarily responsible for the M dwarf rotation morphology, and not quirks of later angular momentum (AM) evolution. Such early mass trends must be taken into account when constructing initial conditions for future studies of stellar rotation. Finally, we show that the average M star loses ˜25%-40% of its AM between 10 and 125 Myr, a figure accurately and generically predicted by modern solar-calibrated wind models. Their success rules out a lossless PMS and validates the extrapolation of magnetic wind laws designed for solar-type stars to the low-mass regime at early times.

  20. MR Imaging of Rotator Cuff Tears: Correlation with Arthroscopy

    Science.gov (United States)

    Bhandary, Sudarshan; Khandige, Ganesh; Kabra, Utkarsh

    2017-01-01

    Introduction Rotator cuff tears are quite common and can cause significant disability. Magnetic Resonance Imaging (MRI) has now emerged as the modality of choice in the preoperative evaluation of patients with rotator cuff injuries, in view of its improved inherent soft tissue contrast and resolution. Aim To evaluate the diagnostic accuracy of routine MRI in the detection and characterisation of rotator cuff tears, by correlating the findings with arthroscopy. Materials and Methods This prospective study was carried out between July 2014 and August 2016 at the AJ Institute of Medical Sciences, Mangalore, Karnataka, India. A total of 82 patients were diagnosed with rotator cuff injury on MRI during this period, out of which 45 patients who underwent further evaluation with arthroscopy were included in this study. The data collected was analysed for significant correlation between MRI diagnosis and arthroscopic findings using kappa statistics. The sensitivity, specificity, predictive value and accuracy of MRI for the diagnosis of full and partial thickness tears were calculated using arthroscopic findings as the reference standard. Results There were 27 males and 18 females in this study. The youngest patient was 22 years and the oldest was 74 years. Majority of rotator cuff tears (78%) were seen in patients above the age of 40 years. MRI showed a sensitivity of 89.6%, specificity of 100%, positive predictive value of 100% and negative predictive value of 83.3% for the diagnosis of full thickness rotator cuff tears. For partial thickness tears, MRI showed a sensitivity of 100%, specificity of 86.6%, positive predictive value of 78.9% and negative predictive value of 100%. The accuracy was 93.1% for full thickness tears and 91.1% for partial thickness tears. The p-value was less than 0.01 for both full and partial thickness tears. There was good agreement between the MRI and arthroscopic findings, with kappa value of 0.85 for full thickness tears and 0.81 for partial

  1. A possible interrelation between Earth rotation and climatic variability at decadal time-scale

    Directory of Open Access Journals (Sweden)

    Leonid Zotov

    2016-05-01

    Full Text Available Using multichannel singular spectrum analysis (MSSA we decomposed climatic time series into principal components, and compared them with Earth rotation parameters. The global warming trends were initially subtracted. Similar quasi 60 and 20 year periodic oscillations have been found in the global mean Earth temperature anomaly (HadCRUT4 and global mean sea level (GMSL. Similar cycles were also found in Earth rotation variation. Over the last 160 years multi-decadal change of Earth's rotation velocity is correlated with the 60-year temperature anomaly, and Chandler wobble envelope reproduces the form of the 60-year oscillation noticed in GMSL. The quasi 20-year oscillation observed in GMSL is correlated with the Chandler wobble excitation. So, we assume that Earth's rotation and climate indexes are connected. Despite of all the clues hinting this connection, no sound conclusion can be done as far as ocean circulation modelling is not able to correctly catch angular momentum of the oscillatory modes.

  2. Time-Frequency Analysis of Signals Generated by Rotating Machines

    Directory of Open Access Journals (Sweden)

    R. Zetik

    1999-06-01

    Full Text Available This contribution is devoted to the higher order time-frequency analyses of signals. Firstly, time-frequency representations of higher order (TFRHO are defined. Then L-Wigner distribution (LWD is given as a special case of TFRHO. Basic properties of LWD are illustrated based on the analysis of mono-component and multi-component synthetic signals and acoustical signals generated by rotating machine. The obtained results confirm usefulness of LWD application for the purpose of rotating machine condition monitoring.

  3. Real-Time Rotational Activity Detection in Atrial Fibrillation

    Science.gov (United States)

    Ríos-Muñoz, Gonzalo R.; Arenal, Ángel; Artés-Rodríguez, Antonio

    2018-01-01

    Rotational activations, or spiral waves, are one of the proposed mechanisms for atrial fibrillation (AF) maintenance. We present a system for assessing the presence of rotational activity from intracardiac electrograms (EGMs). Our system is able to operate in real-time with multi-electrode catheters of different topologies in contact with the atrial wall, and it is based on new local activation time (LAT) estimation and rotational activity detection methods. The EGM LAT estimation method is based on the identification of the highest sustained negative slope of unipolar signals. The method is implemented as a linear filter whose output is interpolated on a regular grid to match any catheter topology. Its operation is illustrated on selected signals and compared to the classical Hilbert-Transform-based phase analysis. After the estimation of the LAT on the regular grid, the detection of rotational activity in the atrium is done by a novel method based on the optical flow of the wavefront dynamics, and a rotation pattern match. The methods have been validated using in silico and real AF signals. PMID:29593566

  4. Correlation of glenohumeral internal rotation deficit and total rotational motion to shoulder injuries in professional baseball pitchers.

    Science.gov (United States)

    Wilk, Kevin E; Macrina, Leonard C; Fleisig, Glenn S; Porterfield, Ronald; Simpson, Charles D; Harker, Paul; Paparesta, Nick; Andrews, James R

    2011-02-01

    Glenohumeral internal rotation deficit (GIRD) indicates a 20° or greater loss of internal rotation of the throwing shoulder compared with the nondominant shoulder. To determine whether GIRD and a deficit in total rotational motion (external rotation + internal rotation) compared with the nonthrowing shoulder correlate with shoulder injuries in professional baseball pitchers. Case series; Level of evidence, 4. Over 3 competitive seasons (2005 to 2007), passive range of motion measurements were evaluated on the dominant and nondominant shoulders for 170 pitcher-seasons. This included 122 professional pitchers during the 3 seasons of data collection, in which some pitchers were measured during multiple seasons. Ranges of motion were measured with a bubble goniometer during the preseason, by the same examiner each year. External and internal rotation of the glenohumeral joint was assessed with the participant supine and the arm abducted 90° in the plane of the scapula, with the scapula stabilized anteriorly at the coracoid process. The reproducibility of the test methods had an intraclass correlation coefficient of .81. Days in which the player was unable to participate because of injury or surgery were recorded during the season by the medical staff of the team and defined as an injury. Pitchers with GIRD (n = 40) were nearly twice as likely to be injured as those without but without statistical significance (P = .17). Pitchers with total rotational motion deficit greater than 5° had a higher rate of injury. Minor league pitchers were more likely than major league pitchers to be injured. However, when players were injured, major league pitchers missed a significantly greater number of games than minor league pitchers. Compared with pitchers without GIRD, pitchers with GIRD appear to be at a higher risk for injury and shoulder surgery.

  5. Sonographic Visualization of the Rotator Cable in Patients With Symptomatic Full-Thickness Rotator Cuff Tears: Correlation With Tear Size, Muscular Fatty Infiltration and Atrophy, and Functional Outcome.

    Science.gov (United States)

    Bureau, Nathalie J; Blain-Paré, Etienne; Tétreault, Patrice; Rouleau, Dominique M; Hagemeister, Nicola

    2016-09-01

    To assess the prevalence of sonographic visualization of the rotator cable in patients with symptomatic full-thickness rotator cuff tears and asymptomatic controls and to correlate rotator cable visualization with tear size, muscular fatty infiltration and atrophy, and the functional outcome in the patients with rotator cuff tears. Fifty-seven patients with rotator cuff tears and 30 asymptomatic volunteers underwent shoulder sonography for prospective assessment of the rotator cable and rotator cuff tear and responded to 2 functional outcome questionnaires (shortened Disabilities of the Arm, Shoulder, and Hand [QuickDASH] and Constant). In the patients with rotator cuff tears, appropriate tests were used to correlate rotator cable visualization with the tear size, functional outcome, muscular fatty infiltration, and atrophy. The patients with rotator cuff tears included 25 women and 32 men (mean age,57 years; range, 39-67 years), and the volunteers included 13 women and 17 men (mean age, 56 years; range, 35-64 years). The rotator cable was identified in 77% (23 of 30) of controls and 23% (13 of 57) of patients with rotator cuff tears. In the patients, nonvisualization of the rotator cable correlated with larger tears (P tears than asymptomatic controls and was associated with a larger tear size and greater supraspinatus fatty infiltration and atrophy. Diligent assessment of the supraspinatus muscle should be done in patients with rotator cuff tears without a visible rotator cable, as the integrity of these anatomic structures may be interdependent.

  6. Time-scales of stellar rotational variability and starspot diagnostics

    Science.gov (United States)

    Arkhypov, Oleksiy V.; Khodachenko, Maxim L.; Lammer, Helmut; Güdel, Manuel; Lüftinger, Teresa; Johnstone, Colin P.

    2018-01-01

    The difference in stability of starspot distribution on the global and hemispherical scales is studied in the rotational spot variability of 1998 main-sequence stars observed by Kepler mission. It is found that the largest patterns are much more stable than smaller ones for cool, slow rotators, whereas the difference is less pronounced for hotter stars and/or faster rotators. This distinction is interpreted in terms of two mechanisms: (1) the diffusive decay of long-living spots in activity complexes of stars with saturated magnetic dynamos, and (2) the spot emergence, which is modulated by gigantic turbulent flows in convection zones of stars with a weaker magnetism. This opens a way for investigation of stellar deep convection, which is yet inaccessible for asteroseismology. Moreover, a subdiffusion in stellar photospheres was revealed from observations for the first time. A diagnostic diagram was proposed that allows differentiation and selection of stars for more detailed studies of these phenomena.

  7. Failed healing of rotator cuff repair correlates with altered collagenase and gelatinase in supraspinatus and subscapularis tendons.

    Science.gov (United States)

    Robertson, Catherine M; Chen, Christopher T; Shindle, Michael K; Cordasco, Frank A; Rodeo, Scott A; Warren, Russell F

    2012-09-01

    Despite improvements in arthroscopic rotator cuff repair technique and technology, a significant rate of failed tendon healing persists. Improving the biology of rotator cuff repairs may be an important focus to decrease this failure rate. The objective of this study was to determine the mRNA biomarkers and histological characteristics of repaired rotator cuffs that healed or developed persistent defects as determined by postoperative ultrasound. Increased synovial inflammation and tendon degeneration at the time of surgery are correlated with the failed healing of rotator cuff tendons. Case-control study; Level of evidence, 3. Biopsy specimens from the subscapularis tendon, supraspinatus tendon, glenohumeral synovium, and subacromial bursa of 35 patients undergoing arthroscopic rotator cuff repair were taken at the time of surgery. Expression of proinflammatory cytokines, tissue remodeling genes, and angiogenesis factors was evaluated by quantitative real-time polymerase chain reaction. Histological characteristics of the affected tissue were also assessed. Postoperative (>6 months) ultrasound was used to evaluate the healing of the rotator cuff. General linear modeling with selected mRNA biomarkers was used to predict rotator cuff healing. Thirty patients completed all analyses, of which 7 patients (23%) had failed healing of the rotator cuff. No differences in demographic data were found between the defect and healed groups. American Shoulder and Elbow Surgeons shoulder scores collected at baseline and follow-up showed improvement in both groups, but there was no significant difference between groups. Increased expression of matrix metalloproteinase 1 (MMP-1) and MMP-9 was found in the supraspinatus tendon in the defect group versus the healed group (P = .006 and .02, respectively). Similar upregulation of MMP-9 was also found in the subscapularis tendon of the defect group (P = .001), which was consistent with the loss of collagen organization as determined by

  8. Correlation between physical examination and three-dimensional gait analysis in the assessment of rotational abnormalities in children with cerebral palsy.

    Science.gov (United States)

    Teixeira, Fernando Borge; Ramalho Júnior, Amancio; Morais Filho, Mauro César de; Speciali, Danielli Souza; Kawamura, Catia Miyuki; Lopes, José Augusto Fernandes; Blumetti, Francesco Camara

    2018-01-01

    Objective To evaluate the correlation between physical examination data concerning hip rotation and tibial torsion with transverse plane kinematics in children with cerebral palsy; and to determine which time points and events of the gait cycle present higher correlation with physical examination findings. Methods A total of 195 children with cerebral palsy seen at two gait laboratories from 2008 and 2016 were included in this study. Physical examination measurements included internal hip rotation, external hip rotation, mid-point hip rotation and the transmalleolar axis angle. Six kinematic parameters were selected for each segment to assess hip rotation and shank-based foot rotation. Correlations between physical examination and kinematic measures were analyzed by Spearman correlation coefficients, and a significance level of 5% was considered. Results Comparing physical examination measurements of hip rotation and hip kinematics, we found moderate to strong correlations for all variables (pphysical examination and hip rotation kinematics (rho range: 0.48-0.61). Moderate correlations were also found between the transmalleolar axis angle measurement on physical examination and foot rotation kinematics (rho range 0.44-0.56; p<0.001). Conclusion These findings may have clinical implications in the assessment and management of transverse plane gait deviations in children with cerebral palsy.

  9. Do Magnetic Resonance Imaging Characteristics of Full-Thickness Rotator Cuff Tears Correlate With Sleep Disturbance?

    Science.gov (United States)

    Reyes, Bryan A; Hull, Brandon R; Kurth, Alexander B; Kukowski, Nathan R; Mulligan, Edward P; Khazzam, Michael S

    2017-11-01

    Many patients with rotator cuff tears suffer from nocturnal shoulder pain, resulting in sleep disturbance. To determine whether rotator cuff tear size correlated with sleep disturbance in patients with full-thickness rotator cuff tears. Cross-sectional study; Level of evidence, 3. Patients with a diagnosis of unilateral full-thickness rotator cuff tears (diagnosed via magnetic resonance imaging [MRI]) completed the Pittsburgh Sleep Quality Index (PSQI), a visual analog scale (VAS) quantifying their shoulder pain, and the American Shoulder and Elbow Surgeons (ASES) questionnaire. Shoulder MRI scans were analyzed for anterior-posterior tear size (mm), tendon retraction (mm), Goutallier grade (0-4), number of tendons involved (1-4), muscle atrophy (none, mild, moderate, or severe), and humeral head rise (present or absent). Bivariate correlations were calculated between the MRI characteristics and baseline survey results. A total of 209 patients with unilateral full-thickness rotator cuff tears were included in this study: 112 (54%) female and 97 (46%) male (mean age, 64.1 years). On average, shoulder pain had been present for 24 months. The mean PSQI score was 9.8, and the mean VAS score was 5.0. No significant correlations were found between any of the rotator cuff tear characteristics and sleep quality. Only tendon retraction had a significant correlation with pain. Although rotator cuff tears are frequently associated with nocturnal pain and sleep disruption, this study demonstrated that morphological characteristics of full-thickness rotator cuff tears, such as size and tendon retraction, do not correlate with sleep disturbance and have little to no correlation with pain levels.

  10. Hybrid state-space time integration of rotating beams

    DEFF Research Database (Denmark)

    Krenk, Steen; Nielsen, Martin Bjerre

    2012-01-01

    An efficient time integration algorithm for the dynamic equations of flexible beams in a rotating frame of reference is presented. The equations of motion are formulated in a hybrid state-space format in terms of local displacements and local components of the absolute velocity. With inspiration...... of the system rotation enter via global operations with the angular velocity vector. The algorithm is based on an integrated form of the equations of motion with energy and momentum conserving properties, if a kinematically consistent non-linear formulation is used. A consistent monotonic scheme for algorithmic...... energy dissipation in terms of local displacements and velocities, typical of structural vibrations, is developed and implemented in the form of forward weighting of appropriate mean value terms in the algorithm. The algorithm is implemented for a beam theory with consistent quadratic non...

  11. Effects of pair correlation functions on intermolecular nuclear relaxation by translational and rotational diffusion in liquids

    International Nuclear Information System (INIS)

    Fries, P.

    1978-01-01

    In order to study the intermolecular relaxation due to magnetic dipolar interactions, we calculate the spectral densities resulting from random translational and rotational motions of spherical molecules carrying off-centre spins. The relative translational motion is treated in the frame-work of a general diffusion equation (the Smoluchowski equation) which takes into account the existence of effective forces between the molecules. This model implies a pair correlation function. i.e. a non unifom relative distribution of the molecules. The analytical calculations are carried out by taking correctly into account the hard sphere boundary conditions for the molecules. Explicit numerical calculations of the spectral densities are performed using finite difference methods and the pair correlation function of Verlet and Weiss obtained by computer experiments. The resulting calculations allow one to interpret the relaxation exhibited by benzene and some of its monohalogen derivatives which has been measured by Jonas et al. at various pressures. The effects of pair correlation and eccentricity contribute to a noticeable enhancement of the spectral densities, especially as the frequency increases. The translational correlation times calculated from the Stokes formula and those deduced from intermolecular relaxation studies are compared. It is shown that in order to distinguish which of the dynamical models is appropriate, measurements must be made as a function of frequency [fr

  12. A correlative study of aortic valve rotation angle and thoracic aortic sizes using ECG gated CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Saremi, Farhood, E-mail: fsaremi@usc.edu; Cen, Steven; Tayari, Nazila; Alizadeh, Houman; Emami, Amir; Lin, Leah; Fleischman, Fernando

    2017-04-15

    Objective: Various degrees of aortic valve rotation may be seen in individuals with no history of congenital cardiovascular malformations, but its association with aortic sizes has not been studied. Methods: Gated computed tomographic (CT angiograms in 217 patients were studied (66.7 ± 15; 22–97 years old)). Aortic diameters were determined at 5 anatomic locations. The length of the aorta from sinus to left subclavian artery was measured. The angle of valve rotation was recorded by measuring the angle between a line connecting the midpoint of the non-coronary sinus to the anterior commissure and another line along the interatrial septum. Rotation angles were correlated with aortic measurements. Patients were separated into two groups based on aortic sizes and into three groups based on age. The threshold for aortic dilatation was set at maximum ascending aorta diameter ≥40 mm (≥21 mm body surface area [BSA] indexed). Results: No significant difference in rotation angles was seen between the three age groups or between genders. Rotation angles were significantly correlated with maximal, average, and BSA adjustment of the aortic root and ascending aortic measurements. The aortic root angles were significantly different between the dilated versus nondilated aortas. There was no significant association between the rotation angles and age, length of ascending aorta, or diameters of descending aorta. Multivariate adaptive regression splines showed 25° of aortic root rotation as the diagnostic cut off for ascending aorta dilation. Above the 25° rotation, every 10° of increasing rotation was associated with a 3.78 ± 0.87 mm increase in aortic diameter (p < 0.01) and a 1.73 ± 0.25 times increased risk for having a dilated aorta (p < 0.01). Conclusion: Rotation angles of the aortic valve may be an independent non-invasive imaging marker for dilatation of the ascending aorta. Patients with increased rotation angle of the aortic valve may have higher risk for

  13. Correlations of the chemical shift on fasly rotating biological solids by means of NMR spectroscopy

    International Nuclear Information System (INIS)

    Herbst, Christian

    2010-01-01

    The basic aim of the thesis was the development and improvement of homo- and heteronuclear feedback sequences for the generation of correlation spectra of the chemical shift. In a first step the possibility of the acquisition of 13 C- 13 correlation spectra of the chemical shift by means of inversion pulses with low RF power factor was studied. Furthermore it was shown that broad-band phase-modulated inversion and universal rotational pulses can be constructed by means of global optimization procedures like the genetic algorithms under regardment of the available RF field strength. By inversion, universal rotational, and 360 pulses as starting values of the optimization efficient homonuclear CN n ν and RN n ν mixing sequences as well as heteronuclear RN n ν s ,ν k feedback sequences were generated. The satisfactory power of the numerically optimized sequences was shown by means of the simulation as well by means of correlation experiments of the chemical shift of L-histidine, L-arginine, and the (CUG) 97 -RNA. This thesis deals furthermore with the possibility to acquire simultaneously different signals with several receivers. By means of numerically optimized RN n ν s ,ν k pulse sequences both 15 N- 13 C and 13 C- 15 N correlation spectra were simultaneously generated. Furthermore it could be shown that the simultaneous acquisition of 3D- 15 N- 13 C- 13 C and 13 C- 15 N-( 1 H)- 1 H correlation spectra is possible. By this in only one measurement process resonance assignments can be met and studies of the global folding performed. A further application of several receivers is the simultaneous acquisition of CHHC, NHHN, NHHC, as well as CHHN spectra. By such experiments it is possible to characterize the hydrogen-bonding pattern and the glycosidic torsion angle χ in RNA. This was demonstrated by means of the (CUG) 97 -RNA. The simultaneous acquisition of all relevant crossing signals of the correlation spectra leads not only to an essential time saving, but

  14. Late-time dynamics of rapidly rotating black holes

    International Nuclear Information System (INIS)

    Glampedakis, K.; Andersson, N.

    2001-01-01

    We study the late-time behaviour of a dynamically perturbed rapidly rotating black hole. Considering an extreme Kerr black hole, we show that the large number of virtually undamped quasinormal modes (that exist for nonzero values of the azimuthal eigenvalue m) combine in such a way that the field (as observed at infinity) oscillates with an amplitude that decays as 1/t at late times. For a near extreme black hole, these modes, collectively, give rise to an exponentially decaying field which, however, is considerably 'long-lived'. Our analytic results are verified using numerical time-evolutions of the Teukolsky equation. Moreover, we argue that the physical mechanism behind the observed behaviour is the presence of a 'superradiance resonance cavity' immediately outside the black hole. We present this new feature in detail, and discuss whether it may be relevant for astrophysical black holes. (author)

  15. The Cherenkov correlated timing detector: materials, geometry and timing constraints

    International Nuclear Information System (INIS)

    Aronstein, D.; Bergfeld, T.; Horton, D.; Palmer, M.; Selen, M.; Thayer, G.; Boyer, V.; Honscheid, K.; Kichimi, H.; Sugaya, Y.; Yamaguchi, H.; Yoshimura, Y.; Kanda, S.; Olsen, S.; Ueno, K.; Tamura, N.; Yoshimura, K.; Lu, C.; Marlow, D.; Mindas, C.; Prebys, E.; Pomianowski, P.

    1996-01-01

    The key parameters of Cherenkov correlated timing (CCT) detectors are discussed. Measurements of radiator geometry, optical properties of radiator and coupling materials, and photon detector timing performance are presented. (orig.)

  16. TIME-DEPENDENT NONEXTENSIVITY ARISING FROM THE ROTATIONAL EVOLUTION OF SOLAR-TYPE STARS

    Energy Technology Data Exchange (ETDEWEB)

    Silva, J. R. P.; Nepomuceno, M. M. F.; Soares, B. B.; De Freitas, D. B., E-mail: joseronaldo@uern.br [Departamento de Física, Universidade do Estado do Rio Grande do Norte, Mossoró-RN (Brazil)

    2013-11-01

    Nonextensive formalism is a generalization of the Boltzmann-Gibbs statistics. In this formalism, the entropic index q is a quantity characterizing the degree of nonextensivity and is interpreted as a parameter of long-memory or long-range interactions between the components of the system. Since its proposition in 1988, this formalism has been applied to investigate a wide variety of natural phenomena. In stellar astrophysics, a theoretical distribution function based on nonextensive formalism (q distributions) has been successfully applied to reproduce the distribution of stellar radial and rotational velocity data. In this paper, we investigate the time variation of the entropic index q obtained from the distribution of rotation, Vsin i, for a sample of 254 rotational data for solar-type stars from 11 open clusters aged between 35.5 Myr and 2.6 Gyr. As a result, we have found an anti-correlation between the entropic index q and the age of clusters, and that the distribution of rotation Vsin i for these stars becomes extensive for an age greater than about 170 Myr. Assuming that the parameter q is associated with long-memory effects, we suggest that the memory of the initial angular momentum of solar-type stars can be scaled by the entropic index q. We also propose a physical link between the parameter q and the magnetic braking of stellar rotation.

  17. Long time correlations in standard mapping

    International Nuclear Information System (INIS)

    Rolland, P.

    1985-09-01

    Using an original method based on a statistics of runs, we have shown the existence of long time correlations in the Standard Mapping, as well as the role they play in the increase of the diffusion coefficient [fr

  18. Exponential time-dependent perturbation theory in rotationally inelastic scattering

    International Nuclear Information System (INIS)

    Cross, R.J.

    1983-01-01

    An exponential form of time-dependent perturbation theory (the Magnus approximation) is developed for rotationally inelastic scattering. A phase-shift matrix is calculated as an integral in time over the anisotropic part of the potential. The trajectory used for this integral is specified by the diagonal part of the potential matrix and the arithmetic average of the initial and final velocities and the average orbital angular momentum. The exponential of the phase-shift matrix gives the scattering matrix and the various cross sections. A special representation is used where the orbital angular momentum is either treated classically or may be frozen out to yield the orbital sudden approximation. Calculations on Ar+N 2 and Ar+TIF show that the theory generally gives very good agreement with accurate calculations, even where the orbital sudden approximation (coupled-states) results are seriously in error

  19. Characteristic time for halo current growth and rotation

    Energy Technology Data Exchange (ETDEWEB)

    Boozer, Allen H., E-mail: ahb17@columbia.edu [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

    2015-10-15

    A halo current flows for part of its path through the plasma edge and for part through the chamber walls and during tokamak disruptions can be as large as tenths of the plasma current. The primary interest in halo currents is the large force that they can exert on machine components particularly if the toriodal rotation of the halo current resonates with a natural oscillation frequency of the tokamak device. Halo currents arise when required to slow down the growth of a kink that is too unstable to be stabilized by the chamber walls. The width of the current channel in the halo plasma is comparable to the amplitude of the kink, and the halo current grows linearly, not exponentially, in time. The current density in the halo is comparable to that of the main plasma body. The rocket force due to plasma flowing out of the halo and recombining on the chamber walls can cause the non-axisymmetric magnetic structure produced by the kink to rotate toroidally at a speed comparable to the halo speed of sound. Gerhardt's observations of the halo current in NSTX shot 141 687 [Nucl. Fusion 53, 023005 (2013)] illustrate many features of the theory of halo currents and are discussed as a summary of the theory.

  20. Algebraic relaxation of a time correlation function

    International Nuclear Information System (INIS)

    Srivastava, S.; Kumar, C.N.; Tankeshwar, K.

    2004-06-01

    A second order non-linear differential equation obtained from Mori's integro- differential equation is shown to transform to another form which provides algebraic decay to a time correlation function. Involved parameters in algebraic formula are related to exact properties of the corresponding correlation function. The model has been used to study a sol-gel system which is known, experimentally, to exhibit a power law decay to stress auto-correlation function. The expression obtained for the viscosity shows a logarithmic divergence at some critical value of the parameter. Some features of the model have also been tested using available information about Lennard-Jones fluids. (author)

  1. Phase correlation of foreign exchange time series

    Science.gov (United States)

    Wu, Ming-Chya

    2007-03-01

    Correlation of foreign exchange rates in currency markets is investigated based on the empirical data of USD/DEM and USD/JPY exchange rates for a period from February 1 1986 to December 31 1996. The return of exchange time series is first decomposed into a number of intrinsic mode functions (IMFs) by the empirical mode decomposition method. The instantaneous phases of the resultant IMFs calculated by the Hilbert transform are then used to characterize the behaviors of pricing transmissions, and the correlation is probed by measuring the phase differences between two IMFs in the same order. From the distribution of phase differences, our results show explicitly that the correlations are stronger in daily time scale than in longer time scales. The demonstration for the correlations in periods of 1986-1989 and 1990-1993 indicates two exchange rates in the former period were more correlated than in the latter period. The result is consistent with the observations from the cross-correlation calculation.

  2. Portal pressure correlated to visceral circulation times

    Energy Technology Data Exchange (ETDEWEB)

    Friman, L [Serafimerlasarettet, Stockholm (Sweden)

    1979-01-01

    Visceral angiography was performed in 7 patients with normal portal pressure and in 10 with portal hypertension. Circulation times, size of vessels and portal pressure were determined. At celiac angiography, a direct correlation was found between time for maximum filling of portal vein and portal pressure, provided no vascular abnormalities existed. At superior mesenteric angiography such a correlation was not found; loss of flow by shunts in portal hypertension being one explanation. Portocaval shunts are common in the celiac system, but uncommon in the superior mesenteric system.

  3. Portal pressure correlated to visceral circulation times

    International Nuclear Information System (INIS)

    Friman, L.

    1979-01-01

    Visceral angiography was performed in 7 patients with normal portal pressure and in 10 with portal hypertension. Circulation times, size of vessels and portal pressure were determined. At celiac angiography, a direct correlation was found between time for maximum filling of portal vein and portal pressure, provided no vascular abnormalities existed. At superior mesenteric angiography such a correlation was not found; loss of flow by shunts in portal hypertension being one explanation. Portocaval shunts are common in the celiac system, but uncommon in the superior mesenteric system. (Auth.)

  4. Spin Chirality of Cu3 and V3 Nanomagnets. 1. Rotation Behavior of Vector Chirality, Scalar Chirality, and Magnetization in the Rotating Magnetic Field, Magnetochiral Correlations.

    Science.gov (United States)

    Belinsky, Moisey I

    2016-05-02

    The rotation behavior of the vector chirality κ, scalar chirality χ, and magnetization M in the rotating magnetic field H1 is considered for the V3 and Cu3 nanomagnets, in which the Dzialoshinsky-Moriya coupling is active. The polar rotation of the field H1 of the given strength H1 results in the energy spectrum characterized by different vector and scalar chiralities in the ground and excited states. The magnetochiral correlations between the vector and scalar chiralities, energy, and magnetization in the rotating field were considered. Under the uniform polar rotation of the field H1, the ground-state chirality vector κI performs sawtooth oscillations and the magnetization vector MI performs the sawtooth oscillating rotation that is accompanied by the correlated transformation of the scalar chirality χI. This demonstrates the magnetochiral effect of the joint rotation behavior and simultaneous frustrations of the spin chiralities and magnetization in the rotating field, which are governed by the correlation between the chiralities and magnetization.

  5. Correlation and multifractality in climatological time series

    International Nuclear Information System (INIS)

    Pedron, I T

    2010-01-01

    Climate can be described by statistical analysis of mean values of atmospheric variables over a period. It is possible to detect correlations in climatological time series and to classify its behavior. In this work the Hurst exponent, which can characterize correlation and persistence in time series, is obtained by using the Detrended Fluctuation Analysis (DFA) method. Data series of temperature, precipitation, humidity, solar radiation, wind speed, maximum squall, atmospheric pressure and randomic series are studied. Furthermore, the multifractality of such series is analyzed applying the Multifractal Detrended Fluctuation Analysis (MF-DFA) method. The results indicate presence of correlation (persistent character) in all climatological series and multifractality as well. A larger set of data, and longer, could provide better results indicating the universality of the exponents.

  6. Time-dependent correlations in electricity markets

    International Nuclear Information System (INIS)

    Alvarez-Ramirez, Jose; Escarela-Perez, Rafael

    2010-01-01

    In the last years, many electricity markets were subjected to deregulated operation where prices are set by the action of market participants. In this form, producers and consumers rely on demand and price forecasts to decide their bidding strategies, allocate assets, negotiate bilateral contracts, hedge risks, and plan facility investments. A basic feature of efficient market hypothesis is the absence of correlations between price increments over any time scale leading to random walk-type behavior of prices, so arbitrage is not possible. However, recent studies have suggested that this is not the case and correlations are present in the behavior of diverse electricity markets. In this paper, a temporal quantification of electricity market correlations is made by means of detrended fluctuation and Allan analyses. The approach is applied to two Canadian electricity markets, Ontario and Alberta. The results show the existence of correlations in both demand and prices, exhibiting complex time-dependent behavior with lower correlations in winter while higher in summer. Relatively steady annual cycles in demand but unstable cycles in prices are detected. On the other hand, the more significant nonlinear effects (measured in terms of a multifractality index) are found for winter months, while the converse behavior is displayed during the summer period. In terms of forecasting models, our results suggest that nonlinear recursive models (e.g., feedback NNs) should be used for accurate day-ahead price estimation. In contrast, linear models can suffice for demand forecasting purposes. (author)

  7. Long-time correlations in the stochastic regime

    International Nuclear Information System (INIS)

    Karney, C.F.F.

    1982-11-01

    The phase space for Hamiltonians of two degrees of freedom is usually divided into stochastic and integrable components. Even when well into the stochastic regime, integrable orbits may surround small stable regions or islands. The effect of these islands on the correlation function for the stochastic trajectories is examined. Depending on the value of the parameter describing the rotation number for the elliptic fixed point at the center of the island, the long-time correlation function may decay as t -5 or exponentially, but more commonly it decays much more slowly (roughly as t -1 ). As a consequence these small islands may have a profound effect on the properties such as the diffusion coefficient, of the stochastic orbits

  8. Unequal-time correlators for cosmology

    Science.gov (United States)

    Kitching, T. D.; Heavens, A. F.

    2017-03-01

    Measurements of the power spectrum from large-scale structure surveys have, to date, assumed an equal-time approximation, where the full cross-correlation power spectrum of the matter density field evaluated at different times (or distances) has been approximated either by the power spectrum at a fixed time or in an improved fashion, by a geometric mean P (k ;r1,r2)=[P (k ;r1)P (k ;r2)]1 /2 . In this paper we investigate the expected impact of the geometric mean ansatz and present an application in assessing the impact on weak-gravitational-lensing cosmological parameter inference, using a perturbative unequal time correlator. As one might expect, we find that the impact of this assumption is greatest at large separations in redshift Δ z ≳0.3 where the change in the amplitude of the matter power spectrum can be as much as 10 percent for k ≳5 h ⁢ Mpc-1 . However, of more concern is that the corrections for small separations, where the clustering is not close to zero, may not be negligibly small. In particular, we find that for a Euclid- or LSST-like weak lensing experiment, the assumption of equal-time correlators may result in biased predictions of the cosmic shear power spectrum, and that the impact is strongly dependent on the amplitude of the intrinsic alignment signal. To compute unequal-time correlations to sufficient accuracy will require advances in either perturbation theory to high k modes or extensive use of simulations.

  9. Wavelet Correlation Coefficient of 'strongly correlated' financial time series

    OpenAIRE

    Razdan, Ashok

    2003-01-01

    In this paper we use wavelet concepts to show that correlation coefficient between two financial data's is not constant but varies with scale from high correlation value to strongly anti-correlation value This studies is important because correlation coefficient is used to quantify degree of independence between two variables. In econophysics correlation coefficient forms important input to evolve hierarchial tree and minimum spanning tree of financial data.

  10. SOLAR CYCLE VARIABILITY AND SURFACE DIFFERENTIAL ROTATION FROM Ca II K-LINE TIME SERIES DATA

    Energy Technology Data Exchange (ETDEWEB)

    Scargle, Jeffrey D.; Worden, Simon P. [NASA Ames Research Center, Moffett Field, CA, 94035 (United States); Keil, Stephen L. [National Solar Observatory, P.O. Box 57, Sunspot, NM 88349 (United States)

    2013-07-01

    Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates 5 components of the variation of the 7 measured chromospheric parameters: (a) the solar cycle (period {approx} 11 yr), (b) quasi-periodic variations (periods {approx} 100 days), (c) a broadband stochastic process (wide range of periods), (d) rotational modulation, and (e) random observational errors, independent of (a)-(d). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these parameters. Time-frequency analysis illuminates periodic and quasi-periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (a) and (b) at timescales in the range {approx}0.1-10 yr. These results using only full-disk data suggest that similar analyses will be useful for detecting and characterizing differential rotation in stars from stellar light curves such as those being produced by NASA's Kepler observatory. Component (c) consists of variations over a range of timescales, in the manner of a 1/f random process with a power-law slope index that varies in a systematic way. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the more rapid variations of the stochastic process (c). Component (d) characterizes differential rotation of the active regions. Component (e) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The data analyzed in this paper can be found at the National Solar Observatory Web site http://nsosp.nso.edu/cak{sub m}on/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters.

  11. Time-dependent friction and solvation time correlation function

    International Nuclear Information System (INIS)

    Samanta, Alok; Ali, Sk Musharaf; Ghosh, Swapan K

    2005-01-01

    We have derived a new relation between the time-dependent friction and solvation time correlation function (STCF) for non-polar fluids. The friction values calculated using this relation and simulation results on STCF for a Lennard-Jones fluid are shown to have excellent agreement with the same obtained through mode-coupling theory. Also derived is a relation between the time-dependent dielectric friction and STCF for polar fluids. Routes are thus provided to obtain the time-dependent friction (non-polar as well as dielectric) from an experimentally measured quantity like STCF, even if the interparticle interaction potential is not known

  12. Nuclear disassembly time scales using space time correlations

    Energy Technology Data Exchange (ETDEWEB)

    Durand, D.; Colin, J.; Lecolley, J.F.; Meslin, C.; Aboufirassi, M.; Bougault, R.; Brou, R. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Bilwes, B.; Cosmo, F. [Strasbourg-1 Univ., 67 (France); Galin, J. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); and others

    1996-09-01

    The lifetime, {tau}, with respect to multifragmentation of highly excited nuclei is deduced from the analysis of strongly damped Pb+Au collisions at 29 MeV/u. The method is based on the study of space-time correlations induced by `proximity` effects between fragments emitted by the two primary products of the reaction and gives the time between the re-separation of the two primary products and the subsequent multifragment decay of one partner. (author). 2 refs.

  13. Nuclear disassembly time scales using space time correlations

    International Nuclear Information System (INIS)

    Durand, D.; Colin, J.; Lecolley, J.F.; Meslin, C.; Aboufirassi, M.; Bougault, R.; Brou, R.; Galin, J.; and others.

    1996-01-01

    The lifetime, τ, with respect to multifragmentation of highly excited nuclei is deduced from the analysis of strongly damped Pb+Au collisions at 29 MeV/u. The method is based on the study of space-time correlations induced by 'proximity' effects between fragments emitted by the two primary products of the reaction and gives the time between the re-separation of the two primary products and the subsequent multifragment decay of one partner. (author)

  14. Flexibility of internal and external glenohumeral rotation of junior female tennis players and its correlation with performance ranking.

    Science.gov (United States)

    Chiang, Ching-Cheng; Hsu, Chih-Chia; Chiang, Jinn-Yen; Chang, Weng-Cheng; Tsai, Jong-Chang

    2016-12-01

    [Purpose] The purpose of this study was to compare the internal and external rotation of the dominant and nondominant shoulders of adolescent female tennis players. The correlation between the shoulder rotation range of motion and the player's ranking was also analyzed. [Subjects and Methods] Twenty-one female junior tennis players who were 13 to 18 years old participated in this study. A standard goniometer was used to measure the internal and external rotation of both glenohumeral joints. The difference in internal and external rotation was calculated as the glenohumeral rotation deficit. The year-end ranking of each player was obtained from the Chinese Taipei Tennis Association. [Results] The internal rotation of the dominant shoulder was significantly smaller than that of the nondominant shoulder. Moreover, player ranking was significantly and negatively correlated with the internal rotation range of motion of both shoulders. On the other hand, the correlations of the internal and external rotation ranges of motion with the age, height, and weight were not significant. [Conclusion] The flexibility of the glenohumeral internal rotation is smaller in the dominant shoulder than of the nondominant shoulder in these junior female tennis players. Flexibility of the glenohumeral internal rotation may be a factor affecting performance in junior female tennis players.

  15. Symptoms of Pain Do Not Correlate with Rotator Cuff Tear Severity

    Science.gov (United States)

    Dunn, Warren R.; Kuhn, John E.; Sanders, Rosemary; An, Qi; Baumgarten, Keith M.; Bishop, Julie Y.; Brophy, Robert H.; Carey, James L.; Holloway, G. Brian; Jones, Grant L.; Ma, C. Benjamin; Marx, Robert G.; McCarty, Eric C.; Poddar, Sourav K.; Smith, Matthew V.; Spencer, Edwin E.; Vidal, Armando F.; Wolf, Brian R.; Wright, Rick W.

    2014-01-01

    Background: For many orthopaedic disorders, symptoms correlate with disease severity. The objective of this study was to determine if pain level is related to the severity of rotator cuff disorders. Methods: A cohort of 393 subjects with an atraumatic symptomatic full-thickness rotator-cuff tear treated with physical therapy was studied. Baseline pretreatment data were used to examine the relationship between the severity of rotator cuff disease and pain. Disease severity was determined by evaluating tear size, retraction, superior humeral head migration, and rotator cuff muscle atrophy. Pain was measured on the 10-point visual analog scale (VAS) in the patient-reported American Shoulder and Elbow Surgeons (ASES) score. A linear multiple regression model was constructed with use of the continuous VAS score as the dependent variable and measures of rotator cuff tear severity and other nonanatomic patient factors as the independent variables. Forty-eight percent of the patients were female, and the median age was sixty-one years. The dominant shoulder was involved in 69% of the patients. The duration of symptoms was less than one month for 8% of the patients, one to three months for 22%, four to six months for 20%, seven to twelve months for 15%, and more than a year for 36%. The tear involved only the supraspinatus in 72% of the patients; the supraspinatus and infraspinatus, with or without the teres minor, in 21%; and only the subscapularis in 7%. Humeral head migration was noted in 16%. Tendon retraction was minimal in 48%, midhumeral in 34%, glenohumeral in 13%, and to the glenoid in 5%. The median baseline VAS pain score was 4.4. Results: Multivariable modeling, controlling for other baseline factors, identified increased comorbidities (p = 0.002), lower education level (p = 0.004), and race (p = 0.041) as the only significant factors associated with pain on presentation. No measure of rotator cuff tear severity correlated with pain (p > 0.25). Conclusions

  16. Hydrogen bonding in protic ionic liquids: structural correlations, vibrational spectroscopy, and rotational dynamics of liquid ethylammonium nitrate

    Science.gov (United States)

    Zentel, Tobias; Overbeck, Viviane; Michalik, Dirk; Kühn, Oliver; Ludwig, Ralf

    2018-02-01

    The properties of the hydrogen bonds in ethylammonium nitrate (EAN) are analyzed by using molecular dynamics simulations and infrared as well as nuclear magnetic resonance experiments. EAN features a flexible three-dimensional network of hydrogen bonds with moderate strengths, which makes it distinct from related triethylammonium-based ionic liquids. First, the network’s flexibility is manifested in a not very pronounced correlation of the hydrogen bond geometries, which is caused by rapid interchanges of bonding partners. The large flexibility of the network also leads to a substantial broadening of the mid-IR absorption band, with the contributions due to N-H stretching motions ranging from 2800 to 3250 cm-1. Finally, the different dynamics are also seen in the rotational correlation of the N-H bond vector, where a correlation time as short as 16.1 ps is observed.

  17. Correlation to predict heat transfer characteristics of a radially rotating heat pipe at vertical position

    Energy Technology Data Exchange (ETDEWEB)

    Waowaew, N.; Terdtoon, P.; Kamonpet, P.; Klongpanich, W. [Chiang Mai University (Thailand). Dept. of Mechanical Engineering; Maezawa, S. [Seikei University (Japan). Dept. of Mechanical Engineering

    2003-06-01

    The heat transfer characteristics of a radially rotating heat pipe (RRHP) depend on a number of parameters. This paper is a study of the effects of these parameters. They are the inner diameter of the tube, aspect ratio, rotational acceleration, working fluid and the dimensionless parameters of heat transfer. RRHPs, made of copper tubes with inner diameters of 11, 26, and 50.4 mm, were used in the experiments. The aspect ratios were 5, 10, 20 and 40 respectively. The selected working fluids were water, ethanol and R123 (CHCI{sub 2}CF{sub 3}) with a filling ratio of 60% of evaporator volume. The experiments were conducted at inclination angles of 0-90{sup o} from horizontal axis and the rotational accelerations were lower, higher and equal to gravitational acceleration. The working temperature was 90{sup o}C. The evaporator section was heated by electric power while heat in the condenser section was removed naturally by air. The evaporator and adiabatic section of the RRHP were well insulated with ceramic fibers. The experimental results showed that the heat flux decreases with an increasing inner diameter, and decreases with an increasing aspect ratio. The heat flux increases with an increasing rotational acceleration and decreases with an increasing liquid density of the working fluid. A correlation to predict the heat transfer rate at vertical position can be established. Further research will investigate a visual study of internal flow pattern and the formulation of a mathematical model. (author)

  18. Faraday's Rotating Wire--The Homopolar Motor: Time to Update?

    Science.gov (United States)

    Auty, Geoff

    2010-01-01

    Answering some of the questions raised in the production of a previous article led to the development of a simple alternative design for the rotating wire demonstration. Significantly, this demonstration avoids the use of mercury as a conducting liquid. The attempt to explain variations in performance of another model and seeking the best…

  19. Space-time correlations in urban sprawl.

    Science.gov (United States)

    Hernando, A; Hernando, R; Plastino, A

    2014-02-06

    Understanding demographic and migrational patterns constitutes a great challenge. Millions of individual decisions, motivated by economic, political, demographic, rational and/or emotional reasons underlie the high complexity of demographic dynamics. Significant advances in quantitatively understanding such complexity have been registered in recent years, as those involving the growth of cities but many fundamental issues still defy comprehension. We present here compelling empirical evidence of a high level of regularity regarding time and spatial correlations in urban sprawl, unravelling patterns about the inertia in the growth of cities and their interaction with each other. By using one of the world's most exhaustive extant demographic data basis--that of the Spanish Government's Institute INE, with records covering 111 years and (in 2011) 45 million people, distributed among more than 8000 population nuclei--we show that the inertia of city growth has a characteristic time of 15 years, and its interaction with the growth of other cities has a characteristic distance of 80 km. Distance is shown to be the main factor that entangles two cities (60% of total correlations). The power of our current social theories is thereby enhanced.

  20. A flexible time recording and time correlation analysis system

    International Nuclear Information System (INIS)

    Shenhav, N.J.; Leiferman, G.; Segal, Y.; Notea, A.

    1983-01-01

    A system was developed to digitize and record the time intervals between detection event pulses, feed to its input channels from a detection device. The accumulated data is transferred continuously in real time to a disc through a PDP 11/34 minicomputer. Even though the system was designed for a specific scope, i.e., the comparative study of passive neutron nondestructive assay methods, it can be characterized by its features as a general purpose time series recorder. The time correlation analysis is performed by software after completion of the data accumulation. The digitizing clock period is selectable and any value, larger than a minimum of 100 ns, may be selected. Bursts of up to 128 events with a frequency up to 10 MHz may be recorded. With the present recorder-minicomputer combination, the maximal average recording frequency is 40 kHz. (orig.)

  1. Real-time estimation of prostate tumor rotation and translation with a kV imaging system based on an iterative closest point algorithm

    International Nuclear Information System (INIS)

    Tehrani, Joubin Nasehi; O’Brien, Ricky T; Keall, Paul; Poulsen, Per Rugaard

    2013-01-01

    Previous studies have shown that during cancer radiotherapy a small translation or rotation of the tumor can lead to errors in dose delivery. Current best practice in radiotherapy accounts for tumor translations, but is unable to address rotation due to a lack of a reliable real-time estimate. We have developed a method based on the iterative closest point (ICP) algorithm that can compute rotation from kilovoltage x-ray images acquired during radiation treatment delivery. A total of 11 748 kilovoltage (kV) images acquired from ten patients (one fraction for each patient) were used to evaluate our tumor rotation algorithm. For each kV image, the three dimensional coordinates of three fiducial markers inside the prostate were calculated. The three dimensional coordinates were used as input to the ICP algorithm to calculate the real-time tumor rotation and translation around three axes. The results show that the root mean square error was improved for real-time calculation of tumor displacement from a mean of 0.97 mm with the stand alone translation to a mean of 0.16 mm by adding real-time rotation and translation displacement with the ICP algorithm. The standard deviation (SD) of rotation for the ten patients was 2.3°, 0.89° and 0.72° for rotation around the right–left (RL), anterior–posterior (AP) and superior–inferior (SI) directions respectively. The correlation between all six degrees of freedom showed that the highest correlation belonged to the AP and SI translation with a correlation of 0.67. The second highest correlation in our study was between the rotation around RL and rotation around AP, with a correlation of −0.33. Our real-time algorithm for calculation of rotation also confirms previous studies that have shown the maximum SD belongs to AP translation and rotation around RL. ICP is a reliable and fast algorithm for estimating real-time tumor rotation which could create a pathway to investigational clinical treatment studies requiring

  2. Critical shoulder angle in an East Asian population: correlation to the incidence of rotator cuff tear and glenohumeral osteoarthritis.

    Science.gov (United States)

    Shinagawa, Kiyotsugu; Hatta, Taku; Yamamoto, Nobuyuki; Kawakami, Jun; Shiota, Yuki; Mineta, Mitsuyoshi; Itoi, Eiji

    2018-05-03

    Focus has recently been on the critical shoulder angle (CSA) as a factor related to rotator cuff tear and osteoarthritis (OA) in the European population. However, whether this relationship is observed in the Asian population is unclear. The correlation between the CSAs measured on anteroposterior radiographs and the presence or absence of rotator cuff tears or OA changes was assessed in 295 patients. Rotator cuff tears were diagnosed with magnetic resonance imaging or ultrasonography. OA findings were classified using the Samilson-Prieto classification. The CSAs among the patients with rotator cuff tears, OA changes, and those without pathologies were compared. Multivariable analyses were used to clarify the potential risks for these pathologies. The mean CSA with rotator cuff tear (33.9° ± 4.1°) was significantly greater than that without a rotator cuff tear (32.3° ± 4.5°; P = .002). Multivariable analysis also showed that a greater CSA had a significantly increased risk of rotator cuff tears, with the odds ratio of 1.08 per degree. OA findings showed no significant correlation to the CSAs. Our study demonstrates that the CSA is greater in those with a rotator cuff tear than in those without a tear or OA changes, which may be an independent risk factor for the incidence of rotator cuff tears in the Japanese population. Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  3. On the Rotating and Oscillating strings in $(AdS_3\\times S^3)_{\\varkappa}$

    CERN Document Server

    Banerjee, Aritra

    2014-01-01

    We study rigidly rotating strings in the $\\varkappa$-deformed $AdS_3 \\times S^3$ background. We find out two classes of solutions corresponding to the giant magnon and single spike solutions of the string rotating is two $S^2_{\\varkappa}$ subspace of rotations reduced along two different isometries. We verify that the dispersion relations reduce to the well known relation in the $\\varkappa\\rightarrow 0$ limit. We further study some oscillating string solutions in the $S^3_{\\varkappa}$ subspace.

  4. Supernova-regulated ISM. V. Space and Time Correlations

    Science.gov (United States)

    Hollins, J. F.; Sarson, G. R.; Shukurov, A.; Fletcher, A.; Gent, F. A.

    2017-11-01

    We apply correlation analysis to random fields in numerical simulations of the supernova-driven interstellar medium (ISM) with the magnetic field produced by dynamo action. We solve the magnetohydrodynamic (MHD) equations in a shearing Cartesian box representing a local region of the ISM, subject to thermal and kinetic energy injection by supernova explosions, and parameterized, optically thin radiative cooling. We consider the cold, warm, and hot phases of the ISM separately; the analysis mostly considers the warm gas, which occupies the bulk of the domain. Various physical variables have different correlation lengths in the warm phase: 40,50, and 60 {pc} for the random magnetic field, density, and velocity, respectively, in the midplane. The correlation time of the random velocity is comparable to the eddy turnover time, about {10}7 {year}, although it may be shorter in regions with a higher star formation rate. The random magnetic field is anisotropic, with the standard deviations of its components {b}x/{b}y/{b}z having approximate ratios 0.5/0.6/0.6 in the midplane. The anisotropy is attributed to the global velocity shear from galactic differential rotation and locally inhomogeneous outflow to the galactic halo. The correlation length of Faraday depth along the z axis, 120 {pc}, is greater than for electron density, 60{--}90 {pc}, and the vertical magnetic field, 60 {pc}. Such comparisons may be sensitive to the orientation of the line of sight. Uncertainties of the structure functions of synchrotron intensity rapidly increase with the scale. This feature is hidden in a power spectrum analysis, which can undermine the usefulness of power spectra for detailed studies of interstellar turbulence.

  5. Rotating Hele-Shaw cell with a time-dependent angular velocity

    Science.gov (United States)

    Anjos, Pedro H. A.; Alvarez, Victor M. M.; Dias, Eduardo O.; Miranda, José A.

    2017-12-01

    Despite the large number of existing studies of viscous flows in rotating Hele-Shaw cells, most investigations analyze rotational motion with a constant angular velocity, under vanishing Reynolds number conditions in which inertial effects can be neglected. In this work, we examine the linear and weakly nonlinear dynamics of the interface between two immiscible fluids in a rotating Hele-Shaw cell, considering the action of a time-dependent angular velocity, and taking into account the contribution of inertia. By using a generalized Darcy's law, we derive a second-order mode-coupling equation which describes the time evolution of the interfacial perturbation amplitudes. For arbitrary values of viscosity and density ratios, and for a range of values of a rotational Reynolds number, we investigate how the time-dependent angular velocity and inertia affect the important finger competition events that traditionally arise in rotating Hele-Shaw flows.

  6. Rotation in the Dynamic Factor Modeling of Multivariate Stationary Time Series.

    Science.gov (United States)

    Molenaar, Peter C. M.; Nesselroade, John R.

    2001-01-01

    Proposes a special rotation procedure for the exploratory dynamic factor model for stationary multivariate time series. The rotation procedure applies separately to each univariate component series of a q-variate latent factor series and transforms such a component, initially represented as white noise, into a univariate moving-average.…

  7. Rotation in the dynamic factor modeling of multivariate stationary time series.

    NARCIS (Netherlands)

    Molenaar, P.C.M.; Nesselroade, J.R.

    2001-01-01

    A special rotation procedure is proposed for the exploratory dynamic factor model for stationary multivariate time series. The rotation procedure applies separately to each univariate component series of a q-variate latent factor series and transforms such a component, initially represented as white

  8. Timing Solution and Single-pulse Properties for Eight Rotating Radio Transients

    Energy Technology Data Exchange (ETDEWEB)

    Cui, B.-Y.; McLaughlin, M. A. [Department of Physics and Astronomy West Virginia University Morgantown, WV 26506 (United States); Boyles, J. [Department of Physics and Astronomy West Kentucky University Bowling Green, KY 42101 (United States); Palliyaguru, N. [Physics and Astronomy Department Texas Tech University Lubbock, TX 79409-1051 (United States)

    2017-05-01

    Rotating radio transients (RRATs), loosely defined as objects that are discovered through only their single pulses, are sporadic pulsars that have a wide range of emission properties. For many of them, we must measure their periods and determine timing solutions relying on the timing of their individual pulses, while some of the less sporadic RRATs can be timed by using folding techniques as we do for other pulsars. Here, based on Parkes and Green Bank Telescope (GBT) observations, we introduce our results on eight RRATs including their timing-derived rotation parameters, positions, and dispersion measures (DMs), along with a comparison of the spin-down properties of RRATs and normal pulsars. Using data for 24 RRATs, we find that their period derivatives are generally larger than those of normal pulsars, independent of any intrinsic correlation with period, indicating that RRATs’ highly sporadic emission may be associated with intrinsically larger magnetic fields. We carry out Lomb–Scargle tests to search for periodicities in RRATs’ pulse detection times with long timescales. Periodicities are detected for all targets, with significant candidates of roughly 3.4 hr for PSR J1623−0841 and 0.7 hr for PSR J1839−0141. We also analyze their single-pulse amplitude distributions, finding that log-normal distributions provide the best fits, as is the case for most pulsars. However, several RRATs exhibit power-law tails, as seen for pulsars emitting giant pulses. This, along with consideration of the selection effects against the detection of weak pulses, imply that RRAT pulses generally represent the tail of a normal intensity distribution.

  9. Timing Solution and Single-pulse Properties for Eight Rotating Radio Transients

    Science.gov (United States)

    Cui, B.-Y.; Boyles, J.; McLaughlin, M. A.; Palliyaguru, N.

    2017-05-01

    Rotating radio transients (RRATs), loosely defined as objects that are discovered through only their single pulses, are sporadic pulsars that have a wide range of emission properties. For many of them, we must measure their periods and determine timing solutions relying on the timing of their individual pulses, while some of the less sporadic RRATs can be timed by using folding techniques as we do for other pulsars. Here, based on Parkes and Green Bank Telescope (GBT) observations, we introduce our results on eight RRATs including their timing-derived rotation parameters, positions, and dispersion measures (DMs), along with a comparison of the spin-down properties of RRATs and normal pulsars. Using data for 24 RRATs, we find that their period derivatives are generally larger than those of normal pulsars, independent of any intrinsic correlation with period, indicating that RRATs’ highly sporadic emission may be associated with intrinsically larger magnetic fields. We carry out Lomb-Scargle tests to search for periodicities in RRATs’ pulse detection times with long timescales. Periodicities are detected for all targets, with significant candidates of roughly 3.4 hr for PSR J1623-0841 and 0.7 hr for PSR J1839-0141. We also analyze their single-pulse amplitude distributions, finding that log-normal distributions provide the best fits, as is the case for most pulsars. However, several RRATs exhibit power-law tails, as seen for pulsars emitting giant pulses. This, along with consideration of the selection effects against the detection of weak pulses, imply that RRAT pulses generally represent the tail of a normal intensity distribution.

  10. MR patterns of rotator cuff impingement lesions and histopathologic correlation of cadaver tendons

    International Nuclear Information System (INIS)

    Rafii, M.; Firooznia, H.; Minkoff, J.; Sherman, O.; Schinella, R.; Weinreb, J.C.; Golimbu, C.; Zazlav, K.

    1989-01-01

    This paper reports shoulder MR examinations of 250 patients retrospectively evaluated and correlated with surgical/arthrographic results in 68 patients and with clinical data in all for assessment of the signal pattern and the configuration of rotator cuff lesions. MR-histopathologic evaluation of the supraspinatus tendon of 8 cadaver shoulders was also correlated with these findings. MR imaging had a sensitivity of 92% in the diagnosis of cuff tears. The most common and accurate criterion for a tear was a tendinous defect, characterized by intense signal on T2-weighted images; less often the torn region consisted of an extremely degenerated and attenuated tendon or was obscured by scar. Presence of secondary findings was mandatory for diagnosis in the latter group. Signal pattern associated with tendonitis varied, and in some simulated that of tendon degeneration (fatty infiltration and fibrillation) or cellular proliferation observed on anatomic specimens. Associated tendinous enlargement and subacromial-subdeltoid bursitis in these patients best correlated with the severity of clinical and surgical findings

  11. An immediate effect of axial neck rotation training with real time visual feedback using a smartphone inclinometer on improvement in axial neck rotation function.

    Science.gov (United States)

    Park, Kyue-Nam; Kwon, Oh-Yun; Kim, Si-Hyun; Jeon, In-Cheol

    2017-03-01

    The purpose of this study was to compare the immediate effects of axial neck rotation training (Axi-NRT) with and without real-time visual feedback (VF) using a smartphone inclinometer on the range of motion (ROM) for axial neck rotation and the onset of compensatory neck lateral bending and extension during active neck rotation. Twenty participants with restricted ROM for neck rotation but no neck pain (21.1 ± 1.6 years and 8 males, 12 females) were recruited for Axi-NRT with VF, and twenty age- and gender-matched participants with restricted ROM for neck rotation were recruited for Axi-NRT without VF. Changes in ROM for neck rotation and the onset time of compensatory neck movement during active neck rotation were measured using an electromagnetic tracking system. Axi-NRT with VF was more effective in increasing ROM for neck rotation and decreasing and delaying the onset of compensatory neck movements during active neck rotation compared with Axi-NRT without VF. Repeated Axi-NRT using VF is useful to educate participants in maintaining the axis of the cervical spine and to increase ROM for axial neck rotation with less compensatory neck motion in participants with a restricted range of neck rotations.

  12. Rotation stability of high speed neutron time-of-flight mechanical chopper

    International Nuclear Information System (INIS)

    Habib, N.; Adib, M.

    1998-01-01

    A modified rotation stabilization system has been designed to maintain the stability of a neutron time-of-flight (TOF) mechanical chopper rates from 460 rpm to 16000 rpm. The main principle of the system is based on comparing the chopper's rotation period with the preselected one from a quartz timer. The result of comparison is used to control the current driver of the chopper's motor. A 600 Hz three phase generator controlled by a magnetic amplifier was used as a current driver. The stability of the chopper's rotation rate at 16000 rpm was 0.02%. An improved method precise time scale calibration of the TOF spectrometer is applied

  13. Improvement of a new rotation function for molecular replacement by designing new scoring functions and dynamic correlation coefficient

    Science.gov (United States)

    Jiang, Fan; Ding, Wei

    2010-10-01

    A previously published new rotation function has been improved by using a dynamic correlation coefficient as well as two new scoring functions of relative entropy and mean-square-residues to make the rotation function more robust and independent of a specific set of weights for scoring and ranking. The previously described new rotation function calculates the rotation function of molecular replacement by matching the search model directly with the Patterson vector map. The signal-to-noise ratio for the correct match was increased by averaging all the matching peaks. Several matching scores were employed to evaluate the goodness of matching. These matching scores were then combined into a single total score by optimizing a set of weights using the linear regression method. It was found that there exists an optimal set of weights that can be applied to the global rotation search and the correct solution can be ranked in the top 100 or less. However, this set of optimal weights in general is dependent on the search models and the crystal structures with different space groups and cell parameters. In this work, we try to solve this problem by designing a dynamic correlation coefficient. It is shown that the dynamic correlation coefficient works for a variety of space groups and cell parameters in the global search of rotation function. We also introduce two new matching scores: relative entropy and mean-square-residues. Last but not least, we discussed a valid method for the optimization of the adjustable parameters for matching vectors.

  14. Numerical simulation in three space dimensions of time-dependent thermal convection in a rotating fluid

    International Nuclear Information System (INIS)

    Hathaway, D.H.; Somerville, R.C.J.; National Solar Observatory, Sunspot, NM; California Univ., La Jolla)

    1985-01-01

    Three-dimensional, time-dependent convection in a plane layer of fluid, uniformly heated from below and subject to vertical shear and to rotation about an axis tilted from the vertical, was simulated by the numerical solution of the Boussinesq equations, including all Coriolis terms. Rotation about a vertical axis produces smaller convection cells with diminished heat fluxes and considerable vorticity. When the rotation axis is tilted from the vertical to represent tropical latitudes, the convection cells become elongated in a N-S direction. Imposed flows with constant vertical shear produce convective rolls aligned with the mean flow. When the rotation vector is tilted from the vertical, the competing effects due to rotation and shear can stabilize the convective motions. 15 references

  15. 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.

  16. HIGH-RESOLUTION ULTRASONOGRAPHY OF SHOULDER FOR ROTATOR CUFF TEAR: CORRELATION WITH ARTHROSCOPIC FINDINGS

    OpenAIRE

    Vishnumurthy H. Y; Jagdeesh K. S; Anand K; Ranoji Mane; Sanath G. Kamte; Fathima Zohra; Banerji B. H; Sathish Servegar

    2016-01-01

    INTRODUCTION Rotator cuff disease is the most common cause of shoulder pain. Ultrasonography being non-invasive, widely available, more cost-effective method and is the first choice in imaging of rotator cuff tears. Arthroscopy of shoulder is considered as the gold standard for diagnosis of rotator cuff tears. Objective of this study was to compare the diagnostic accuracy of high-resolution ultrasonography of shoulder for rotator cuff tears with arthroscopy of shoulder. METHODS...

  17. Shoulder Rotator Muscle Dynamometry Characteristics: Side Asymmetry and Correlations with Ball-Throwing Speed in Adolescent Handball Players

    Science.gov (United States)

    Pontaga, Inese; Zidens, Janis

    2014-01-01

    The aim of the investigation was to: 1) compare shoulder external/internal rotator muscles’ peak torques and average power values and their ratios in the dominant and non-dominant arm; 2) determine correlations between shoulder rotator muscles’ peak torques, average power and ball-throwing speed in handball players. Fourteen 14 to 15-year-old male athletes with injury-free shoulders participated in the study (body height: 176 ± 7 cm, body mass 63 ± 9 kg). The tests were carried out by an isokinetic dynamometer system in the shoulder internal and external rotation movements at angular velocities of 60°/s, 90°/s and 240°/s during concentric contractions. The eccentric external– concentric internal rotator muscle contractions were performed at the velocity of 90°/s. The player threw a ball at maximal speed keeping both feet on the floor. The speed was recorded with reflected light rays. Training in handball does not cause significant side asymmetry in shoulder external/internal rotator muscle peak torques or the average power ratio. Positive correlations between isokinetic characteristics of the shoulder internal and external rotator muscles and ball-throwing speed were determined. The power produced by internal rotator muscles during concentric contractions after eccentric contractions of external rotator muscles was significantly greater in the dominant than in the non-dominant arm. Thus, it may be concluded that the shoulder eccentric external/concentric internal rotator muscle power ratio is significantly greater than this ratio in the concentric contractions of these muscles. PMID:25414738

  18. Shoulder Rotator Muscle Dynamometry Characteristics: Side Asymmetry and Correlations with Ball-Throwing Speed in Adolescent Handball Players

    Directory of Open Access Journals (Sweden)

    Pontaga Inese

    2014-10-01

    Full Text Available The aim of the investigation was to: 1 compare shoulder external/internal rotator muscles’ peak torques and average power values and their ratios in the dominant and non-dominant arm; 2 determine correlations between shoulder rotator muscles’ peak torques, average power and ball-throwing speed in handball players. Fourteen 14 to 15- year-old male athletes with injury-free shoulders participated in the study (body height: 176 ± 7 cm, body mass 63 ± 9 kg. The tests were carried out by an isokinetic dynamometer system in the shoulder internal and external rotation movements at angular velocities of 60°/s, 90°/s and 240°/s during concentric contractions. The eccentric external- concentric internal rotator muscle contractions were performed at the velocity of 90°/s. The player threw a ball at maximal speed keeping both feet on the floor. The speed was recorded with reflected light rays. Training in handball does not cause significant side asymmetry in shoulder external/internal rotator muscle peak torques or the average power ratio. Positive correlations between isokinetic characteristics of the shoulder internal and external rotator muscles and ball-throwing speed were determined. The power produced by internal rotator muscles during concentric contractions after eccentric contractions of external rotator muscles was significantly greater in the dominant than in the non-dominant arm. Thus, it may be concluded that the shoulder eccentric external/concentric internal rotator muscle power ratio is significantly greater than this ratio in the concentric contractions of these muscles

  19. Paleomagnetic constraints on the timing and distribution of Cenozoic rotations in Central and Eastern Anatolia

    Science.gov (United States)

    Gürer, Derya; van Hinsbergen, Douwe J. J.; Özkaptan, Murat; Creton, Iverna; Koymans, Mathijs R.; Cascella, Antonio; Langereis, Cornelis G.

    2018-03-01

    To quantitatively reconstruct the kinematic evolution of Central and Eastern Anatolia within the framework of Neotethyan subduction accommodating Africa-Eurasia convergence, we paleomagnetically assess the timing and amount of vertical axis rotations across the Ulukışla and Sivas regions. We show paleomagnetic results from ˜ 30 localities identifying a coherent rotation of a SE Anatolian rotating block comprised of the southern Kırşehir Block, the Ulukışla Basin, the Central and Eastern Taurides, and the southern part of the Sivas Basin. Using our new and published results, we compute an apparent polar wander path (APWP) for this block since the Late Cretaceous, showing that it experienced a ˜ 30-35° counterclockwise vertical axis rotation since the Oligocene time relative to Eurasia. Sediments in the northern Sivas region show clockwise rotations. We use the rotation patterns together with known fault zones to argue that the counterclockwise-rotating domain of south-central Anatolia was bounded by the Savcılı Thrust Zone and Deliler-Tecer Fault Zone in the north and by the African-Arabian trench in the south, the western boundary of which is poorly constrained and requires future study. Our new paleomagnetic constraints provide a key ingredient for future kinematic restorations of the Anatolian tectonic collage.

  20. Paleomagnetic constraints on the timing and distribution of Cenozoic rotations in Central and Eastern Anatolia

    Directory of Open Access Journals (Sweden)

    D. Gürer

    2018-03-01

    Full Text Available To quantitatively reconstruct the kinematic evolution of Central and Eastern Anatolia within the framework of Neotethyan subduction accommodating Africa–Eurasia convergence, we paleomagnetically assess the timing and amount of vertical axis rotations across the Ulukışla and Sivas regions. We show paleomagnetic results from ∼ 30 localities identifying a coherent rotation of a SE Anatolian rotating block comprised of the southern Kırşehir Block, the Ulukışla Basin, the Central and Eastern Taurides, and the southern part of the Sivas Basin. Using our new and published results, we compute an apparent polar wander path (APWP for this block since the Late Cretaceous, showing that it experienced a ∼ 30–35° counterclockwise vertical axis rotation since the Oligocene time relative to Eurasia. Sediments in the northern Sivas region show clockwise rotations. We use the rotation patterns together with known fault zones to argue that the counterclockwise-rotating domain of south-central Anatolia was bounded by the Savcılı Thrust Zone and Deliler–Tecer Fault Zone in the north and by the African–Arabian trench in the south, the western boundary of which is poorly constrained and requires future study. Our new paleomagnetic constraints provide a key ingredient for future kinematic restorations of the Anatolian tectonic collage.

  1. Time correlation in two-photon decay

    International Nuclear Information System (INIS)

    Hrasko, P.

    1979-11-01

    The relative time distribution of the photons emitted in a second order non-cascade process b→a+2γ is investigated under the assumption that only those photon pairs are detected which were emitted a sufficiently long time after the preparation of the decaying state. An anticorrelation between the photons is found and attributed to the propagation of one of the photons backward in time. (author)

  2. [Correlation of fine structures of distributions of amplitudes of a photomultiplier dark current fluctuations with the Earth rotations about its axis].

    Science.gov (United States)

    Fedorov, M V; Belousov, L V; Voeĭkov, V L; Zenchenko, K I; Zenchenko, T A; Konradov, A A; Shnol', S E

    2001-01-01

    The fine structures of distributions of photomultiplier dark current fluctuations measured in two laboratories 2000 km distant from other: in the international Institute of Biophysics (Neuss, Germany) and in the Moscow State University (Moscow, Russia) were compared. It is shown that similar forms of appropriate histograms are apparently more often realized at both locations at the same local time. This confirms the previous conclusion that the fine structure of distributions correlates with rotation of the Earth about its axis.

  3. Time-varying correlation and common structures in volatility

    NARCIS (Netherlands)

    Liu, Yang

    2016-01-01

    This thesis studies time series properties of the covariance structure of multivariate asset returns. First, the time-varying feature of correlation is investigated at the intraday level with a new correlation model incorporating the intraday correlation dynamics. Second, the thesis develops a

  4. Variations in VLT/UVES-based OH rotational temperatures for time scales from hours to 15 years

    Science.gov (United States)

    Noll, Stefan; Kimeswenger, Stefan; Proxauf, Bastian; Kausch, Wolfgang; Unterguggenberger, Stefanie; Jones, Amy M.

    2017-04-01

    Hydroxyl (OH) emission is an important tracer of the climate, chemistry, and dynamics of the Earth's mesopause region. However, the relation of intensity variations in different OH lines is not well understood yet. This is critical for the most popular use of OH lines: the estimate of ambient temperatures based on transitions at low rotational levels of the same band. It is possible that the measured variability of the derived rotational temperature does not coincide with changes in the ambient temperature. Such differences can be caused by varying deviations from the local thermodynamic equilibrium (LTE) for the population distribution over the considered rotational levels. The non-LTE effects depend on the ratio of the thermalising collisions (mostly related to molecular oxygen) and competing radiative transitions or collisions without thermalisation of the rotational level distribution. Therefore, significant changes in the vertical structure of excited OH and its main quenchers can affect the temperature measurements. We have investigated the variability of OH rotational temperatures and the corresponding contributions of non-LTE effects for different OH bands and time scales up to 15 years based on data of the high-resolution echelle spectrograph UVES at the Very Large Telescope at Cerro Paranal in Chile. In order to link the measured rotational temperatures with the structure of the OH emission layer, we have also studied OH emission and kinetic temperature profiles from the multi-channel radiometer SABER on the TIMED satellite taken between 2002 and 2015. The results show that non-LTE contributions can significantly affect the OH rotational temperatures. Their variations can be especially strong during the night and for high upper vibrational levels of the transitions, where amplitudes of several Kelvins can be measured. They appear to be weak if long-term variations such as those caused by the solar cycle are investigated. These differences in the response

  5. Rattleback dynamics and its reversal time of rotation

    Science.gov (United States)

    Kondo, Yoichiro; Nakanishi, Hiizu

    2017-06-01

    A rattleback is a rigid, semielliptic toy which exhibits unintuitive behavior; when it is spun in one direction, it soon begins pitching and stops spinning, then it starts to spin in the opposite direction, but in the other direction, it seems to spin just steadily. This puzzling behavior results from the slight misalignment between the principal axes for the inertia and those for the curvature; the misalignment couples the spinning with the pitching and the rolling oscillations. It has been shown that under the no-slip condition and without dissipation the spin can reverse in both directions, and Garcia and Hubbard obtained the formula for the time required for the spin reversal tr [Proc. R. Soc. Lond. A 418, 165 (1988), 10.1098/rspa.1988.0078]. In this work, we reformulate the rattleback dynamics in a physically transparent way and reduce it to a three-variable dynamics for spinning, pitching, and rolling. We obtain an expression of the Garcia-Hubbard formula for tr by a simple product of four factors: (1) the misalignment angle, (2) the difference in the inverses of inertia moment for the two oscillations, (3) that in the radii for the two principal curvatures, and (4) the squared frequency of the oscillation. We perform extensive numerical simulations to examine validity and limitation of the formula, and find that (1) the Garcia-Hubbard formula is good for both spinning directions in the small spin and small oscillation regime, but (2) in the fast spin regime especially for the steady direction, the rattleback may not reverse and shows a rich variety of dynamics including steady spinning, spin wobbling, and chaotic behavior reminiscent of chaos in a dissipative system.

  6. HIGH-RESOLUTION ULTRASONOGRAPHY OF SHOULDER FOR ROTATOR CUFF TEAR: CORRELATION WITH ARTHROSCOPIC FINDINGS

    Directory of Open Access Journals (Sweden)

    Vishnumurthy H. Y

    2016-09-01

    Full Text Available INTRODUCTION Rotator cuff disease is the most common cause of shoulder pain. Ultrasonography being non-invasive, widely available, more cost-effective method and is the first choice in imaging of rotator cuff tears. Arthroscopy of shoulder is considered as the gold standard for diagnosis of rotator cuff tears. Objective of this study was to compare the diagnostic accuracy of high-resolution ultrasonography of shoulder for rotator cuff tears with arthroscopy of shoulder. METHODS Thirty patients clinically suspected to have rotator cuff tear who underwent ultrasonography and arthroscopy of shoulder were included in the study. Duration of study was for two years. All ultrasonography examinations were conducted in ultrasound machine using GE Voluson 730 PRO high frequency (10-12 MHz linear array transducer done by two experienced radiologists. Arthroscopies were done by two experienced shoulder arthroscopic surgeons. RESULTS Age of the patients with rotator cuff tears ranged from 40 to 80 years. 57% were females and 43% were males among the patients who had rotator cuff tears. 71.43% of the rotator cuff tears were found in the dominant arm. 64.28% of patients with rotator cuff tear had given history of fall or trauma to the corresponding shoulder within 6 months prior to presentation. 39.28% of patients who had rotator cuff tears were known diabetics. Supraspinatus tendon was the most commonly affected tendon, followed by infraspinatus and subscapularis tendons. For overall detection of rotator cuff tears, ultrasonography in comparison with the arthroscopy has sensitivity and specificity of 92.85% and 100%. For detection of full thickness rotator cuff tear, its sensitivity and specificity was 94.73% and 100% and for partial thickness rotator cuff tears 76.92% and 100%. Ultrasonography has 100% sensitivity and specificity for detection of supraspinatus full thickness tear. For supraspinatus partial thickness tear, sensitivity and specificity was 88

  7. Determination of enoxaparin with rotational thrombelastometry using the prothrombinase-induced clotting time reagent.

    Science.gov (United States)

    Schaden, Eva; Schober, Andreas; Hacker, Stefan; Spiss, Christian; Chiari, Astrid; Kozek-Langenecker, Sibylle

    2010-04-01

    Drug monitoring of low molecular weight heparin is generally not recommended, but could be reasonable in critically ill patients, whose risk for bleeding or thrombosis shows a high interpatient variability. Anti-Xa assays are not available around the clock even in central hospitals, whereas rotational thrombelastometry (ROTEM) becomes increasingly used at the bedside. Prothrombinase-induced clotting time (PiCT) reagent allows determination of factor Xa-inhibition in plasma. The aim of our study was to evaluate enoxaparin determination in whole blood with the ROTEM using specific test modifications, including PiCT. After ethics committee's approval, citrated whole blood obtained from overall 16 healthy volunteers was incubated with enoxaparin at 16 different anti-Xa concentrations. Main endpoint was the clotting time (CT) in ROTEM representing initial activation of clot formation. CT was determined in the new PiCT-ROTEM test, in a low-tissue factor-activated modification (LowTF-ROTEM) as well as in the commercially available heparin-sensitive ROTEM assays (HEPTEM and INTEM). In the absence of enoxaparin, CT values were 168.6 +/- 6.1 s (PiCT-ROTEM), 247.3 +/- 18.6 s (LowTF-ROTEM), and -6.2 +/- 7.9 s (INTEM-HEPTEM). A linear dependency (P anti-Xa concentration and CT was found for PiCT-ROTEM, LowTF-ROTEM, and for INTEM-HEPTEM with correlation coefficients of 0.93 for PiCT-ROTEM, 0.94 for LowTF-ROTEM, and 0.81 for INTEM-HEPTEM. This in-vitro experiment demonstrates a strong correlation between enoxaparin anti-Xa concentrations and specific ROTEM tests. These promising assays should be further evaluated for monitoring anticoagulation in high-risk patients in clinical studies.

  8. Electronic structure and time-dependent description of rotational predissociation of LiH

    DEFF Research Database (Denmark)

    Jasik, P.; Sienkiewicz, J. E.; Domsta, J.

    2017-01-01

    parameters and the experimental ones. The dynamics of the rotational predissociation process of the 11Π state were studied by solving the time-dependent Schrödinger equation. The classical experiment of Velasco [Can. J. Phys., 1957, 35, 1204] on dissociation in the 11Π state is explained for the first time...

  9. Comparison of rotational temperature derived from ground-based OH airglow observations with TIMED/SABER to evaluate the Einstein Coefficients

    Science.gov (United States)

    Liu, W.; Xu, J.; Smith, A. K.; Yuan, W.

    2017-12-01

    Ground-based observations of the OH(9-4, 8-3, 6-2, 5-1, 3-0) band airglows over Xinglong, China (40°24'N, 117°35'E) from December 2011 to 2014 are used to calculate rotational temperatures. The temperatures are calculated using five commonly used Einstein coefficient datasets. The kinetic temperature from TIMED/SABER is completely independent of the OH rotational temperature. SABER temperatures are weighted vertically by weighting functions calculated for each emitting vibrational state from two SABER OH volume emission rate profiles. By comparing the ground-based OH rotational temperature with SABER's, five Einstein coefficient datasets are evaluated. The results show that temporal variations of the rotational temperatures are well correlated with SABER's; the linear correlation coefficients are higher than 0.72, but the slopes of the fit between the SABER and rotational temperatures are not equal to 1. The rotational temperatures calculated using each set of Einstein coefficients produce a different bias with respect to SABER; these are evaluated over each of vibrational levels to assess the best match. It is concluded that rotational temperatures determined using any of the available Einstein coefficient datasets have systematic errors. However, of the five sets of coefficients, the rotational temperature derived with the Langhoff et al.'s (1986) set is most consistent with SABER. In order to get a set of optimal Einstein coefficients for rotational temperature derivation, we derive the relative values from ground-based OH spectra and SABER temperatures statistically using three year data. The use of a standard set of Einstein coefficients will be beneficial for comparing rotational temperatures observed at different sites.

  10. Improvement of a new rotation function for molecular replacement by designing new scoring functions and dynamic correlation coefficient

    International Nuclear Information System (INIS)

    Fan, Jiang; Wei, Ding

    2010-01-01

    A previously published new rotation function has been improved by using a dynamic correlation coefficient as well as two new scoring functions of relative entropy and mean-square-residues to make the rotation function more robust and independent of a specific set of weights for scoring and ranking. The previously described new rotation function calculates the rotation function of molecular replacement by matching the search model directly with the Patterson vector map. The signal-to-noise ratio for the correct match was increased by averaging all the matching peaks. Several matching scores were employed to evaluate the goodness of matching. These matching scores were then combined into a single total score by optimizing a set of weights using the linear regression method. It was found that there exists an optimal set of weights that can be applied to the global rotation search and the correct solution can be ranked in the top 100 or less. However, this set of optimal weights in general is dependent on the search models and the crystal structures with different space groups and cell parameters. In this work, we try to solve this problem by designing a dynamic correlation coefficient. It is shown that the dynamic correlation coefficient works for a variety of space groups and cell parameters in the global search of rotation function. We also introduce two new matching scores: relative entropy and mean-square-residues. Last but not least, we discussed a valid method for the optimization of the adjustable parameters for matching vectors. (condensed matter: structure, thermal and mechanical properties)

  11. Magnetic cycles and rotation periods of late-type stars from photometric time series

    Science.gov (United States)

    Suárez Mascareño, A.; Rebolo, R.; González Hernández, J. I.

    2016-10-01

    Aims: We investigate the photometric modulation induced by magnetic activity cycles and study the relationship between rotation period and activity cycle(s) in late-type (FGKM) stars. Methods: We analysed light curves, spanning up to nine years, of 125 nearby stars provided by the All Sky Automated Survey (ASAS). The sample is mainly composed of low-activity, main-sequence late-A to mid-M-type stars. We performed a search for short (days) and long-term (years) periodic variations in the photometry. We modelled the light curves with combinations of sinusoids to measure the properties of these periodic signals. To provide a better statistical interpretation of our results, we complement our new results with results from previous similar works. Results: We have been able to measure long-term photometric cycles of 47 stars, out of which 39 have been derived with false alarm probabilities (FAP) of less than 0.1 per cent. Rotational modulation was also detected and rotational periods were measured in 36 stars. For 28 stars we have simultaneous measurements of activity cycles and rotational periods, 17 of which are M-type stars. We measured both photometric amplitudes and periods from sinusoidal fits. The measured cycle periods range from 2 to 14 yr with photometric amplitudes in the range of 5-20 mmag. We found that the distribution of cycle lengths for the different spectral types is similar, as the mean cycle is 9.5 yr for F-type stars, 6.7 yr for G-type stars, 8.5 yr for K-type stars, 6.0 yr for early M-type stars, and 7.1 yr for mid-M-type stars. On the other hand, the distribution of rotation periods is completely different, trending to longer periods for later type stars, from a mean rotation of 8.6 days for F-type stars to 85.4 days in mid-M-type stars. The amplitudes induced by magnetic cycles and rotation show a clear correlation. A trend of photometric amplitudes with rotation period is also outlined in the data. The amplitudes of the photometric variability

  12. Rotational and translational dynamics and their relation to hydrogen bond lifetimes in an ionic liquid by means of NMR relaxation time experiments and molecular dynamics simulation

    Science.gov (United States)

    Strate, Anne; Neumann, Jan; Overbeck, Viviane; Bonsa, Anne-Marie; Michalik, Dirk; Paschek, Dietmar; Ludwig, Ralf

    2018-05-01

    We report a concerted theoretical and experimental effort to determine the reorientational dynamics as well as hydrogen bond lifetimes for the doubly ionic hydrogen bond +OH⋯O- in the ionic liquid (2-hydroxyethyl)trimethylammonium bis(trifluoromethylsulfonyl)imide [Ch][NTf2] by using a combination of NMR relaxation time experiments, density functional theory (DFT) calculations, and molecular dynamics (MD) simulations. Due to fast proton exchange, the determination of rotational correlation times is challenging. For molecular liquids, 17O-enhanced proton relaxation time experiments have been used to determine the rotational correlation times for the OH vectors in water or alcohols. As an alternative to those expensive isotopic substitution experiments, we employed a recently introduced approach which is providing access to the rotational dynamics from a single NMR deuteron quadrupolar relaxation time experiment. Here, the deuteron quadrupole coupling constants (DQCCs) are obtained from a relation between the DQCC and the δ1H proton chemical shifts determined from a set of DFT calculated clusters in combination with experimentally determined proton chemical shifts. The NMR-obtained rotational correlation times were compared to those obtained from MD simulations and then related to viscosities for testing the applicability of popular hydrodynamic models. In addition, hydrogen bond lifetimes were derived, using hydrogen bond population correlation functions computed from MD simulations. Here, two different time domains were observed: The short-time contributions to the hydrogen lifetimes and the reorientational correlation times have roughly the same size and are located in the picosecond range, whereas the long-time contributions decay with relaxation times in the nanosecond regime and are related to rather slow diffusion processes. The computed average hydrogen bond lifetime is dominated by the long-time process, highlighting the importance and longevity of

  13. Cross-correlation time-of-flight analysis of molecular beam scattering

    International Nuclear Information System (INIS)

    Nowikow, C.V.; Grice, R.

    1979-01-01

    The theory of the cross-correlation method of time-of-flight analysis is presented in a form which highlights its formal similarity to the conventional method. A time-of-flight system for the analysis of crossed molecular beam scattering is described, which is based on a minicomputer interface and can operate in both the cross-correlation and conventional modes. The interface maintains the synchronisation of chopper disc rotation and channel advance indefinitely in the cross-correlation method and can acquire data in phase with the beam modulation in both methods. The shutter function of the cross-correlation method is determined and the deconvolution analysis of the data is discussed. (author)

  14. Time-gated Einstein-Podolsky-Rosen correlation

    International Nuclear Information System (INIS)

    Takei, Nobuyuki; Lee, Noriyuki; Furusawa, Akira; Moriyama, Daiki; Neergaard-Nielsen, J. S.

    2006-01-01

    We experimentally demonstrate the creation and characterization of Einstein-Podolsky-Rosen (EPR) correlation between optical beams in a time-gated fashion. The correlated beams are created with two independent continuous-wave optical parametric oscillators and a half beam splitter. We define the temporal modes using a square temporal filter with duration T and make time-resolved measurements on the generated state. We observe correlations between the relevant conjugate variables in the temporal mode which correspond to EPR correlation. Our scheme is extendable to continuous-variable quantum teleportation of a non-Gaussian state defined in the time domain such as a superposition of coherent states

  15. A conservative quaternion-based time integration algorithm for rigid body rotations with implicit constraints

    DEFF Research Database (Denmark)

    Nielsen, Martin Bjerre; Krenk, Steen

    2012-01-01

    A conservative time integration algorithm for rigid body rotations is presented in a purely algebraic form in terms of the four quaternions components and the four conjugate momentum variables via Hamilton’s equations. The introduction of an extended mass matrix leads to a symmetric set of eight...

  16. Paleomagnetic constraints on the timing and distribution of Cenozoic rotations in Central and Eastern Anatolia

    NARCIS (Netherlands)

    Gürer, Derya; Van Hinsbergen, Douwe J.J.; Özkaptan, Murat; Creton, Iverna; Koymans, Mathijs R.; Cascella, Antonio; Langereis, Cornelis G.

    2018-01-01

    To quantitatively reconstruct the kinematic evolution of Central and Eastern Anatolia within the framework of Neotethyan subduction accommodating Africa-Eurasia convergence, we paleomagnetically assess the timing and amount of vertical axis rotations across the Uluklisla and Sivas regions. We show

  17. Efficient use of correlation entropy for analysing time series data

    Indian Academy of Sciences (India)

    Abstract. The correlation dimension D2 and correlation entropy K2 are both important quantifiers in nonlinear time series analysis. However, use of D2 has been more common compared to K2 as a discriminating measure. One reason for this is that D2 is a static measure and can be easily evaluated from a time series.

  18. Time-dependent dynamical behavior of surface tension on rotating fluids under microgravity environment

    Science.gov (United States)

    Hung, R. J.; Tsao, Y. D.; Hong, B. B.; Leslie, F. W.

    1988-01-01

    Time dependent evolutions of the profile of free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations of the dynamics of bubble shapes have been carried out with the following situations: (1) linear functions of spin-up and spin-down in low and microgravity environments, (2) step functions of spin-up and spin-down in a low gravity environment, and (3) sinusoidal function oscillation of gravity environment in high and low rotating cylinder speeds.

  19. Time-of-flight mass spectrometer using an imaging detector and a rotating electric field

    International Nuclear Information System (INIS)

    Katayama, Atsushi; Kameo, Yutaka; Nakashima, Mikio

    2008-01-01

    A new technique for minor isotope analysis that uses a rotating electric field and an imaging detector is described. The rotating electric field is generated by six cylindrically arranged plane electrodes with multi-phase sinusoidal wave voltage. When ion packets that are discriminated by time-of-flight enter the rotating electric field, they are circularly deflected, rendering a spiral image on the fluorescent screen of the detector. This spiral image represents m/z values of ions as the position and abundance of ions as brightness. For minor isotopes analyses, the micro channel plate detector under gate control operation is used to eliminate the influence of high intensity of major isotopes. (author)

  20. The Diagnostic Reproducibility of Tomosynthesis for the Correlation between Acromiohumeral Distance and Rotator Cuff Size or Type.

    Science.gov (United States)

    Song, Yoonah; Lee, Seunghun; Lee, Bong Gun; Joo, Young Bin; Song, Soon-Young

    2018-01-01

    To correlate the acromiohumeral distance (AHD) using tomosynthesis and rotator cuff (RC) pathology and various anatomical indices and to assess the diagnostic reproducibility of tomosynthesis for the evaluation of subacromial impingement. A retrospective review of 63 patients with clinically suspected subacromial impingement was conducted. Two musculoskeletal radiologists independently measured the following quantitative data: the AHD on plain radiographs and the AHD at three compartments (anterior, middle, and posterior) using tomosynthesis, computed tomography (CT) arthrography, or magnetic resonance (MR) arthrography. To investigate the association between the AHD and RC pathology and various anatomical indices, we reviewed the arthroscopic operation record as the referenced standard. The size of rotator cuff tear (RCT) in full-thickness tears displayed a significant inverse correlation with the middle and the posterior tomosynthetic AHDs ( p tomosynthesis, and CT or MR arthrography ( p tomosynthesis is reproducible compared with other modalities.

  1. The coracoacromial arch: MR evaluation and correlation with rotator cuff pathology

    International Nuclear Information System (INIS)

    Farley, T.E.; Neumann, C.H.; Steinbach, L.S.; Petersen, S.A.

    1994-01-01

    The relative prevalence of various acromial shapes, appearance of the coracoacromial ligament and enthesophytes along the inferior aspect of the acromioclavicular joint in patients with and without rotator cuff tears were evaluated. Of 76 patients with clinical instability and impingement, 31 had a normal rotator cuff and 45 demonstrated a partial or full tear of the supraspinatus tendon at surgery. Results were compared with those from magnetic resonance (MR) scans of 57 asymptomatic volunteers. Of the 45 patients with a supraspinatus tear, 38% (17) had a flat acromial undersurface (type I), 40% (18) had a concave acromial undersurface (type II), 18% (8) had an anteriorly hooked acromion (type III), and 4% (2) had an inferiorly convex acromion (type IV). Among the 31 patients with a normal rotator cuff at surgery and the 57 asymptomatic volunteers, the respective prevalences of the type I acromion were 39% (12) and 44% (25), of type II 48% (15) and 35% (20), type III 3% (1) and 12% (7), and type IV 10% (3) and 9% (5). Shoulders with surgically proven rotator cuff tears showed a tendential association with a type III acromion (8/45) and statistically significant associations with a thickened coracoacromial ligament (17/45) and acromioclavicular enthesophytes (18/45). For the association between inferiorly directed acromioclavicular joint enthesophytes and rotator cuff tears, age appears to be a confounding factor. The type IV acromion, newly classified by this study, does not have a recognizable association with rotator cuff tears. Assessment of the osseous-ligamentous coracoacromial outlet by MR imaging provides useful diagnostic information and may prove helpful to the orthopedic surgeon in patients for whom surgical decompression is contemplated. (orig.)

  2. The coracoacromial arch: MR evaluation and correlation with rotator cuff pathology

    Energy Technology Data Exchange (ETDEWEB)

    Farley, T.E. [San Francisco Magnetic Resonance Center, San Francisco, CA (United States)]|[Florida Hospital, Dept. of Diagnostic Radiology, Orlando, FL (United States); Neumann, C.H. [San Francisco Magnetic Resonance Center, San Francisco, CA (United States)]|[Desert Hospital, Dept. of Radiology, Palm Springs, CA (United States)]|[Univ. of California San Francisco, Dept. of Radiology, San Francisco, CA (United States); Steinbach, L.S. [Univ. of California San Francisco, Dept. of Radiology, San Francisco, CA (United States); Petersen, S.A. [Wayne State Univ. School of Medicine, Dept. of Orthopedic Surgery, Detroit, MI (United States)

    1994-11-01

    The relative prevalence of various acromial shapes, appearance of the coracoacromial ligament and enthesophytes along the inferior aspect of the acromioclavicular joint in patients with and without rotator cuff tears were evaluated. Of 76 patients with clinical instability and impingement, 31 had a normal rotator cuff and 45 demonstrated a partial or full tear of the supraspinatus tendon at surgery. Results were compared with those from magnetic resonance (MR) scans of 57 asymptomatic volunteers. Of the 45 patients with a supraspinatus tear, 38% (17) had a flat acromial undersurface (type I), 40% (18) had a concave acromial undersurface (type II), 18% (8) had an anteriorly hooked acromion (type III), and 4% (2) had an inferiorly convex acromion (type IV). Among the 31 patients with a normal rotator cuff at surgery and the 57 asymptomatic volunteers, the respective prevalences of the type I acromion were 39% (12) and 44% (25), of type II 48% (15) and 35% (20), type III 3% (1) and 12% (7), and type IV 10% (3) and 9% (5). Shoulders with surgically proven rotator cuff tears showed a tendential association with a type III acromion (8/45) and statistically significant associations with a thickened coracoacromial ligament (17/45) and acromioclavicular enthesophytes (18/45). For the association between inferiorly directed acromioclavicular joint enthesophytes and rotator cuff tears, age appears to be a confounding factor. The type IV acromion, newly classified by this study, does not have a recognizable association with rotator cuff tears. Assessment of the osseous-ligamentous coracoacromial outlet by MR imaging provides useful diagnostic information and may prove helpful to the orthopedic surgeon in patients for whom surgical decompression is contemplated. (orig.)

  3. Modal Analysis in Periodic, Time-Varying Systems with emphasis to the Coupling between Flexible Rotating Beams and Non-Rotating Flexible Structures

    DEFF Research Database (Denmark)

    Saracho, C. M.; Santos, Ilmar

    2003-01-01

    The analysis of dynamical response of a system built by a non-rotating structure coupled to flexible rotating beams is the purpose of this work. The effect of rotational speed upon the beam natural frequencies is well-known, so that an increase in the angular speeds leads to an increase in beam...... natural frequencies, the so-called centrifugal stiffening. The equations of motion of such a global system present matrices with time-depending coefficients, which vary periodically with the angular rotor speed, and introduce parametric vibrations into the system response. The principles of modal analysis...... for time-invariant linear systems are expanded to investigate time-varying systems. Concepts as eigenvalues and eigenvectors, which in this special case are also time-varying, are used to analyse the dynamical response of global system. The time-varying frequencies and modes are also illustrated....

  4. Phase transition and angular momentum dependence of correlations in the rotational spectra of Ne20 and Ne22

    International Nuclear Information System (INIS)

    Satpathy, L.; Schmid, K.W.; Krewald, S.; Faessler, A.

    1974-01-01

    Multi-Configuration-Hartree-Fock (MCHF) calculations with angular momentum projection before the variation of the internal degree of freedom have been performed for the nuclei Ne 20 and Ne 22 . This procedure yields different correlated intrinsic states for the different members of a rotational band. Thus, the angular momentum dependence of correlations has been studied. Experimentally, the ground state spectra of Ne 20 and Ne 22 show properties similar to the phase transitions observed in some rare earth nuclei which have been well reproduced through the present calculations. The calculated spectra show a significant improvement compared to the ones obtained by variation before the angular momentum projection is effected. (author)

  5. Finite-correlation-time effects in the kinematic dynamo problem

    International Nuclear Information System (INIS)

    Schekochihin, Alexander A.; Kulsrud, Russell M.

    2001-01-01

    Most of the theoretical results on the kinematic amplification of small-scale magnetic fluctuations by turbulence have been confined to the model of white-noise-like (δ-correlated in time) advecting turbulent velocity field. In this work, the statistics of the passive magnetic field in the diffusion-free regime are considered for the case when the advecting flow is finite-time correlated. A new method is developed that allows one to systematically construct the correlation-time expansion for statistical characteristics of the field such as its probability density function or the complete set of its moments. The expansion is valid provided the velocity correlation time is smaller than the characteristic growth time of the magnetic fluctuations. This expansion is carried out up to first order in the general case of a d-dimensional arbitrarily compressible advecting flow. The growth rates for all moments of the magnetic-field strength are derived. The effect of the first-order corrections due to the finite correlation time is to reduce these growth rates. It is shown that introducing a finite correlation time leads to the loss of the small-scale statistical universality, which was present in the limit of the δ-correlated velocity field. Namely, the shape of the velocity time-correlation profile and the large-scale spatial structure of the flow become important. The latter is a new effect, that implies, in particular, that the approximation of a locally-linear shear flow does not fully capture the effect of nonvanishing correlation time. Physical applications of this theory include the small-scale kinematic dynamo in the interstellar medium and protogalactic plasmas

  6. Efficient quantum algorithm for computing n-time correlation functions.

    Science.gov (United States)

    Pedernales, J S; Di Candia, R; Egusquiza, I L; Casanova, J; Solano, E

    2014-07-11

    We propose a method for computing n-time correlation functions of arbitrary spinorial, fermionic, and bosonic operators, consisting of an efficient quantum algorithm that encodes these correlations in an initially added ancillary qubit for probe and control tasks. For spinorial and fermionic systems, the reconstruction of arbitrary n-time correlation functions requires the measurement of two ancilla observables, while for bosonic variables time derivatives of the same observables are needed. Finally, we provide examples applicable to different quantum platforms in the frame of the linear response theory.

  7. Comparisons of the Various Partial-Thickness Rotator Cuff Tears on MR Arthrography and Arthroscopic Correlation

    International Nuclear Information System (INIS)

    Chun, Kyung Ah; Kim, Min Sung; Kim, Young Joo

    2010-01-01

    To assess the diagnostic performance of MR arthrography in the diagnosis of the various types of partial-thickness rotator cuff tears by comparing the MR imaging findings with the arthroscopic findings. The series of MR arthrography studies included 202 patients consisting of 100 patients with partial-thickness rotator cuff tears proved by arthroscopy and a control group of 102 patients with arthroscopically intact rotator cuffs, which were reviewed in random order. At arthroscopy, 54 articularsided, 26 bursal-sided, 20 both articular- and bursal-sided partial-thickness tears were diagnosed. The MR arthrographies were analyzed by two radiologists for articular-sided tears, bursal-sided tears, and both articular- and bursal-sided tears of the rotator cuff. The sensitivity and specificity of each type of partial-thickness tears were determined. Kappa statistics was calculated to determine the interand intra-observer agreement of the diagnosis of partial-thickness rotator cuff tears. The sensitivity and specificity of the various types of rotator cuff tears were 85% and 90%, respectively for articular-sided tears, 62% and 95% for bursal- sided tears, as well as 45% and 99% for both articular- and bursal-sided tears. False-negative assessments were primarily observed in the diagnosis of bursal-sided tears. Conversely, both articular- and bursal-sided tears were overestimated as full-thickness tears. Inter-observer agreement was excellent for the diagnosis of articular-sided tears (k = 0.70), moderate (k = 0.59) for bursal-sided tears, and fair (k = 0.34) for both articular- and bursal-sided tears, respectively. Intra-observer agreement for the interpretation of articular- and bursal-sided tears was excellent and good, respectively, whereas intra-observer agreement for both articular- and bursal-sided tears was moderate. MR arthrography is a useful diagnostic tool for partial-thickness rotator cuff tears, but has limitations in that it has low sensitivity in bursal- and

  8. Comparisons of the Various Partial-Thickness Rotator Cuff Tears on MR Arthrography and Arthroscopic Correlation

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kyung Ah; Kim, Min Sung; Kim, Young Joo [Catholic University of Korea Uijeongbu St.Mary' s Hospital, Uijeongbu (Korea, Republic of)

    2010-10-15

    To assess the diagnostic performance of MR arthrography in the diagnosis of the various types of partial-thickness rotator cuff tears by comparing the MR imaging findings with the arthroscopic findings. The series of MR arthrography studies included 202 patients consisting of 100 patients with partial-thickness rotator cuff tears proved by arthroscopy and a control group of 102 patients with arthroscopically intact rotator cuffs, which were reviewed in random order. At arthroscopy, 54 articularsided, 26 bursal-sided, 20 both articular- and bursal-sided partial-thickness tears were diagnosed. The MR arthrographies were analyzed by two radiologists for articular-sided tears, bursal-sided tears, and both articular- and bursal-sided tears of the rotator cuff. The sensitivity and specificity of each type of partial-thickness tears were determined. Kappa statistics was calculated to determine the interand intra-observer agreement of the diagnosis of partial-thickness rotator cuff tears. The sensitivity and specificity of the various types of rotator cuff tears were 85% and 90%, respectively for articular-sided tears, 62% and 95% for bursal- sided tears, as well as 45% and 99% for both articular- and bursal-sided tears. False-negative assessments were primarily observed in the diagnosis of bursal-sided tears. Conversely, both articular- and bursal-sided tears were overestimated as full-thickness tears. Inter-observer agreement was excellent for the diagnosis of articular-sided tears (k = 0.70), moderate (k = 0.59) for bursal-sided tears, and fair (k = 0.34) for both articular- and bursal-sided tears, respectively. Intra-observer agreement for the interpretation of articular- and bursal-sided tears was excellent and good, respectively, whereas intra-observer agreement for both articular- and bursal-sided tears was moderate. MR arthrography is a useful diagnostic tool for partial-thickness rotator cuff tears, but has limitations in that it has low sensitivity in bursal- and

  9. Rotator cuff tears: assessment with MR arthrography in 275 patients with arthroscopic correlation

    International Nuclear Information System (INIS)

    Waldt, S.; Bruegel, M.; Mueller, D.; Holzapfel, K.; Rummeny, E.J.; Woertler, K.; Imhoff, A.B.

    2007-01-01

    We assessed the diagnostic performance of magnetic resonance (MR) arthrography in the diagnosis of articular-sided partial-thickness and full-thickness rotator cuff tears in a large symptomatic population. MR arthrograms obtained in 275 patients including a study group of 139 patients with rotator cuff tears proved by arthroscopy and a control group of 136 patients with arthroscopically intact rotator cuff tendons were reviewed in random order. MR imaging was performed on a 1.0 T system (Magnetom Expert, Siemens). MR arthrograms were analyzed by two radiologists in consensus for articular-sided partial-thickness and full-thickness tears of the supraspinatus, infraspinatus, and subscapularis tendons. At arthroscopy, 197 rotator cuff tears were diagnosed, including 105 partial-thickness (93 supraspinatus, nine infraspinatus, three subscapularis) and 92 full-thickness (43 supraspinatus, 20 infraspinatus, 29 subscapularis) tendon tears. For full-thickness tears, sensitivity, specificity, and accuracy were 96%, 99%, and 98%, respectively, and for partial tears 80%, 97%, and 95%, respectively. False negative and positive assessments in the diagnosis of articular-sided partial-thickness tears were predominantly [78% (35/45)] observed with small articular-sided (Ellman grade1) tendon tears. MR arthrography is highly accurate in the diagnosis of full-thickness rotator cuff tears and is accurate in the diagnosis of articular-sided partial-thickness tears. Limitations in the diagnosis of partial-thickness tears are mainly restricted to small articular-sided tears (Ellman grade 1) due to difficulties in differentiation between fiber tearing, tendinitis, synovitic changes, and superficial fraying at tendon margins. (orig.)

  10. Rotator cuff tears: assessment with MR arthrography in 275 patients with arthroscopic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Waldt, S.; Bruegel, M.; Mueller, D.; Holzapfel, K.; Rummeny, E.J.; Woertler, K. [Technische Universitaet Muenchen, Department of Radiology, Munich (Germany); Imhoff, A.B. [Technische Universitaet Muenchen, Department of Sports Orthopedics, Munich (Germany)

    2007-02-15

    We assessed the diagnostic performance of magnetic resonance (MR) arthrography in the diagnosis of articular-sided partial-thickness and full-thickness rotator cuff tears in a large symptomatic population. MR arthrograms obtained in 275 patients including a study group of 139 patients with rotator cuff tears proved by arthroscopy and a control group of 136 patients with arthroscopically intact rotator cuff tendons were reviewed in random order. MR imaging was performed on a 1.0 T system (Magnetom Expert, Siemens). MR arthrograms were analyzed by two radiologists in consensus for articular-sided partial-thickness and full-thickness tears of the supraspinatus, infraspinatus, and subscapularis tendons. At arthroscopy, 197 rotator cuff tears were diagnosed, including 105 partial-thickness (93 supraspinatus, nine infraspinatus, three subscapularis) and 92 full-thickness (43 supraspinatus, 20 infraspinatus, 29 subscapularis) tendon tears. For full-thickness tears, sensitivity, specificity, and accuracy were 96%, 99%, and 98%, respectively, and for partial tears 80%, 97%, and 95%, respectively. False negative and positive assessments in the diagnosis of articular-sided partial-thickness tears were predominantly [78% (35/45)] observed with small articular-sided (Ellman grade1) tendon tears. MR arthrography is highly accurate in the diagnosis of full-thickness rotator cuff tears and is accurate in the diagnosis of articular-sided partial-thickness tears. Limitations in the diagnosis of partial-thickness tears are mainly restricted to small articular-sided tears (Ellman grade 1) due to difficulties in differentiation between fiber tearing, tendinitis, synovitic changes, and superficial fraying at tendon margins. (orig.)

  11. Time-localized wavelet multiple regression and correlation

    Science.gov (United States)

    Fernández-Macho, Javier

    2018-02-01

    This paper extends wavelet methodology to handle comovement dynamics of multivariate time series via moving weighted regression on wavelet coefficients. The concept of wavelet local multiple correlation is used to produce one single set of multiscale correlations along time, in contrast with the large number of wavelet correlation maps that need to be compared when using standard pairwise wavelet correlations with rolling windows. Also, the spectral properties of weight functions are investigated and it is argued that some common time windows, such as the usual rectangular rolling window, are not satisfactory on these grounds. The method is illustrated with a multiscale analysis of the comovements of Eurozone stock markets during this century. It is shown how the evolution of the correlation structure in these markets has been far from homogeneous both along time and across timescales featuring an acute divide across timescales at about the quarterly scale. At longer scales, evidence from the long-term correlation structure can be interpreted as stable perfect integration among Euro stock markets. On the other hand, at intramonth and intraweek scales, the short-term correlation structure has been clearly evolving along time, experiencing a sharp increase during financial crises which may be interpreted as evidence of financial 'contagion'.

  12. Apparatus for Measurements of Time and Space Correlation

    Science.gov (United States)

    Favre, Alexandre; Gaviglio, J; Dumas, R

    1955-01-01

    A brief review is made of improvements to an experimental apparatus for time and space correlation designed for study of turbulence. Included is a description of the control of the measurements and a few particular applications.

  13. Optical rotation calculated with time-dependent density functional theory: the OR45 benchmark.

    Science.gov (United States)

    Srebro, Monika; Govind, Niranjan; de Jong, Wibe A; Autschbach, Jochen

    2011-10-13

    Time-dependent density functional theory (TDDFT) computations are performed for 42 organic molecules and three transition metal complexes, with experimental molar optical rotations ranging from 2 to 2 × 10(4) deg cm(2) dmol(-1). The performances of the global hybrid functionals B3LYP, PBE0, and BHLYP, and of the range-separated functionals CAM-B3LYP and LC-PBE0 (the latter being fully long-range corrected), are investigated. The performance of different basis sets is studied. When compared to liquid-phase experimental data, the range-separated functionals do, on average, not perform better than B3LYP and PBE0. Median relative deviations between calculations and experiment range from 25 to 29%. A basis set recently proposed for optical rotation calculations (LPol-ds) on average does not give improved results compared to aug-cc-pVDZ in TDDFT calculations with B3LYP. Individual cases are discussed in some detail, among them norbornenone for which the LC-PBE0 functional produced an optical rotation that is close to available data from coupled-cluster calculations, but significantly smaller in magnitude than the liquid-phase experimental value. Range-separated functionals and BHLYP perform well for helicenes and helicene derivatives. Metal complexes pose a challenge to first-principles calculations of optical rotation.

  14. Time-odd mean fields in covariant density functional theory: Rotating systems

    International Nuclear Information System (INIS)

    Afanasjev, A. V.; Abusara, H.

    2010-01-01

    Time-odd mean fields (nuclear magnetism) and their impact on physical observables in rotating nuclei are studied in the framework of covariant density functional theory (CDFT). It is shown that they have profound effect on the dynamic and kinematic moments of inertia. Particle number, configuration, and rotational frequency dependencies of their impact on the moments of inertia have been analyzed in a systematic way. Nuclear magnetism can also considerably modify the band crossing features such as crossing frequencies and the properties of the kinematic and dynamic moments of inertia in the band crossing region. The impact of time-odd mean fields on the moments of inertia in the regions away from band crossing only weakly depends on the relativistic mean-field parametrization, reflecting good localization of the properties of time-odd mean fields in CDFT. The moments of inertia of normal-deformed nuclei considerably deviate from the rigid-body value. On the contrary, superdeformed and hyperdeformed nuclei have the moments of inertia which are close to rigid-body value. The structure of the currents in rotating frame, their microscopic origin, and the relations to the moments of inertia have been systematically analyzed. The phenomenon of signature separation in odd-odd nuclei, induced by time-odd mean fields, has been analyzed in detail.

  15. Strategy correlations and timing of adaptation in Minority Games

    OpenAIRE

    Galla, Tobias; Sherrington, David

    2005-01-01

    We study the role of strategy correlations and timing of adaptation for the dynamics of Minority Games, both simulationally and analytically. Using the exact generating functional approach a la De Dominicis we compute the phase diagram and the behaviour of batch and on-line games with correlated strategies, complementing exisiting replica studies of their statics. It is shown that the timing of adaptation can be relevant; while conventional games with uncorrelated strategies are nearly insens...

  16. Robotic real-time translational and rotational head motion correction during frameless stereotactic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinmin; Belcher, Andrew H.; Grelewicz, Zachary; Wiersma, Rodney D., E-mail: rwiersma@uchicago.edu [Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois 60637 (United States)

    2015-06-15

    Purpose: To develop a control system to correct both translational and rotational head motion deviations in real-time during frameless stereotactic radiosurgery (SRS). Methods: A novel feedback control with a feed-forward algorithm was utilized to correct for the coupling of translation and rotation present in serial kinematic robotic systems. Input parameters for the algorithm include the real-time 6DOF target position, the frame pitch pivot point to target distance constant, and the translational and angular Linac beam off (gating) tolerance constants for patient safety. Testing of the algorithm was done using a 4D (XY Z + pitch) robotic stage, an infrared head position sensing unit and a control computer. The measured head position signal was processed and a resulting command was sent to the interface of a four-axis motor controller, through which four stepper motors were driven to perform motion compensation. Results: The control of the translation of a brain target was decoupled with the control of the rotation. For a phantom study, the corrected position was within a translational displacement of 0.35 mm and a pitch displacement of 0.15° 100% of the time. For a volunteer study, the corrected position was within displacements of 0.4 mm and 0.2° over 98.5% of the time, while it was 10.7% without correction. Conclusions: The authors report a control design approach for both translational and rotational head motion correction. The experiments demonstrated that control performance of the 4D robotic stage meets the submillimeter and subdegree accuracy required by SRS.

  17. Locally Rotationally Symmetric Bianchi Type-I Model with Time Varying Λ Term

    International Nuclear Information System (INIS)

    Tiwari, R. K.; Jha, Navin Kumar

    2009-01-01

    We investigate the locally rotationally symmetric (LRS) Bianchi type-I cosmological model for stiff matter and a vacuum solution with a cosmological term proportional to R −m (R is the scale factor and m is a positive constant). The cosmological term decreases with time. We obtain that for both the cases the present universe is accelerating with a large fraction of cosmological density in the form of a cosmological term

  18. Robotic real-time translational and rotational head motion correction during frameless stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Liu, Xinmin; Belcher, Andrew H.; Grelewicz, Zachary; Wiersma, Rodney D.

    2015-01-01

    Purpose: To develop a control system to correct both translational and rotational head motion deviations in real-time during frameless stereotactic radiosurgery (SRS). Methods: A novel feedback control with a feed-forward algorithm was utilized to correct for the coupling of translation and rotation present in serial kinematic robotic systems. Input parameters for the algorithm include the real-time 6DOF target position, the frame pitch pivot point to target distance constant, and the translational and angular Linac beam off (gating) tolerance constants for patient safety. Testing of the algorithm was done using a 4D (XY Z + pitch) robotic stage, an infrared head position sensing unit and a control computer. The measured head position signal was processed and a resulting command was sent to the interface of a four-axis motor controller, through which four stepper motors were driven to perform motion compensation. Results: The control of the translation of a brain target was decoupled with the control of the rotation. For a phantom study, the corrected position was within a translational displacement of 0.35 mm and a pitch displacement of 0.15° 100% of the time. For a volunteer study, the corrected position was within displacements of 0.4 mm and 0.2° over 98.5% of the time, while it was 10.7% without correction. Conclusions: The authors report a control design approach for both translational and rotational head motion correction. The experiments demonstrated that control performance of the 4D robotic stage meets the submillimeter and subdegree accuracy required by SRS

  19. Regularity of the Rotation Number for the One-Dimensional Time-Continuous Schroedinger Equation

    Energy Technology Data Exchange (ETDEWEB)

    Amor, Sana Hadj, E-mail: sana_hadjamor@yahoo.fr [Ecole Nationale d' Ingenieurs de Monastir (Tunisia)

    2012-12-15

    Starting from results already obtained for quasi-periodic co-cycles in SL(2, R), we show that the rotation number of the one-dimensional time-continuous Schroedinger equation with Diophantine frequencies and a small analytic potential has the behavior of a 1/2-Hoelder function. We give also a sub-exponential estimate of the length of the gaps which depends on its label given by the gap-labeling theorem.

  20. The hurst exponent and long-time correlation

    International Nuclear Information System (INIS)

    Wang, G.; Antar, G.; Devynck, P.

    1999-10-01

    The rescaled range statistics (R/S) method is applied to the ion saturation current fluctuations measured by Langmuir probe at edge on Tore Supra to evaluate the Hurst exponent. Data block randomization is carried out to the data sets in order to investigate the relationship between the Hurst exponent and long time correlation. It is observed that h is well above 0.5 in the long time self-similar range. However, it is found that the information which leads to H > 0.5 is totally contained in the short-time correlation and no link to long times is found. (authors)

  1. Test of rotating wheel system for measuring correlated α-decay

    International Nuclear Information System (INIS)

    Wu Xiaolei; Gan Zaiguo; Guo Junsheng; Fan Hongmei; Qin Zhi

    2005-01-01

    A rotating-wheel set-up used for measuring and studying the heavy nuclei with α-decay was built. This system was tested experimentally by using ion-beam from SFC. The test results prove that this set-up was useful and reliable. It provides simple and effective equipment and technique to synthesize and identify new nuclides of Z=107 in the near future. (authors)

  2. Statistical mechanics and correlation properties of a rotating two-dimensional flow of like-sign vortices

    International Nuclear Information System (INIS)

    Viecelli, J.A.

    1993-01-01

    The Hamiltonian flow of a set of point vortices of like sign and strength has a low-temperature phase consisting of a rotating triangular lattice of vortices, and a normal temperature turbulent phase consisting of random clusters of vorticity that orbit about a common center along random tracks. The mean-field flow in the normal temperature phase has similarities with turbulent quasi-two-dimensional rotating laboratory and geophysical flows, whereas the low-temperature phase displays effects associated with quantum fluids. In the normal temperature phase the vortices follow power-law clustering distributions, while in the time domain random interval modulation of the vortex orbit radii fluctuations produces singular fractional exponent power-law low-frequency spectra corresponding to time autocorrelation functions with fractional exponent power-law tails. Enhanced diffusion is present in the turbulent state, whereas in the solid-body rotation state vortices thermally diffuse across the lattice. Over the entire temperature range the interaction energy of a single vortex in the field of the rest of the vortices follows positive temperature Fermi--Dirac statistics, with the zero temperature limit corresponding to the rotating crystal phase, and the infinite temperature limit corresponding to a Maxwellian distribution. Analyses of weather records dependent on the large-scale quasi-two-dimensional atmospheric circulation suggest the presence of singular fractional exponent power-law spectra and fractional exponent power-law autocorrelation tails, consistent with the theory

  3. Finite correlation time effects in kinematic dynamo problem

    International Nuclear Information System (INIS)

    Schekochihin, A.A.; Kulsrud, R.M.

    2000-01-01

    One-point statistics of the magnetic fluctuations in kinematic regime with large Prandtl number and non delta-correlated in time advecting velocity field are studied. A perturbation expansion in the ratio of the velocity correlation time to the dynamo growth time is constructed in the spirit of the Kliatskin-Tatarskii functional method and carried out to first order. The convergence properties are improved compared to the commonly used van Kampen-Terwiel method. The zeroth-order growth rate of the magnetic energy is estimated to be reduced (in three dimensions) by approximately 40%. This reduction is quite close to existing numerical results

  4. Multi-frame pyramid correlation for time-resolved PIV

    NARCIS (Netherlands)

    Sciacchitano, A.; Scarano, F.; Wieneke, B.

    2012-01-01

    A novel technique is introduced to increase the precision and robustness of time-resolved particle image velocimetry (TR-PIV) measurements. The innovative element of the technique is the linear combination of the correlation signal computed at different separation time intervals. The domain of the

  5. Time-varying Entry Heating Profile Replication with a Rotating Arc Jet Test Article

    Science.gov (United States)

    Grinstead, Jay Henderson; Venkatapathy, Ethiraj; Noyes, Eric A.; Mach, Jeffrey J.; Empey, Daniel M.; White, Todd R.

    2014-01-01

    A new approach for arc jet testing of thermal protection materials at conditions approximating the time-varying conditions of atmospheric entry was developed and demonstrated. The approach relies upon the spatial variation of heat flux and pressure over a cylindrical test model. By slowly rotating a cylindrical arc jet test model during exposure to an arc jet stream, each point on the test model will experience constantly changing applied heat flux. The predicted temporal profile of heat flux at a point on a vehicle can be replicated by rotating the cylinder at a prescribed speed and direction. An electromechanical test model mechanism was designed, built, and operated during an arc jet test to demonstrate the technique.

  6. Inertial wave beams and inertial wave modes in a rotating cylinder with time-modulated rotation rate

    Science.gov (United States)

    Borcia, Ion D.; Ghasemi V., Abouzar; Harlander, Uwe

    2014-05-01

    Inertial gravity waves play an crucial role in atmospheres, oceans, and the fluid inside of planets and moons. In the atmosphere, the effect of rotation is neglected for small wavelength and the waves bear the character of internal gravity waves. For long waves, the hydrostatic assumption is made which in turn makes the atmosphere inelastic with respect to inertial motion. In contrast, in the Earth's interior, pure inertial waves are considered as an important fundamental part of the motion. Moreover, as the deep ocean is nearly homogeneous, there the inertial gravity waves bear the character of inertial waves. Excited at the oceans surface mainly due to weather systems the waves can propagate downward and influence the deep oceans motion. In the light of the aforesaid it is important to understand better fundamental inertial wave dynamics. We investigate inertial wave modes by experimental and numerical methods. Inertial modes are excited in a fluid filled rotating annulus by modulating the rotation rate of the outer cylinder and the upper and lower lids. This forcing leads to inertial wave beams emitted from the corner regions of the annulus due to periodic motions in the boundary layers (Klein et al., 2013). When the forcing frequency matches with the eigenfrequency of the rotating annulus the beam pattern amplitude is increasing, the beams broaden and mode structures can be observed (Borcia et al., 2013a). The eigenmodes are compared with analytical solutions of the corresponding inviscid problem (Borcia et al, 2013b). In particular for the pressure field a good agreement can be found. However, shear layers related to the excited wave beams are present for all frequencies. This becomes obvious in particular in the experimental visualizations that are done by using Kalliroscope particles, highlighting relative motion in the fluid. Comparing the eigenfrequencies we find that relative to the analytical frequencies, the experimental and numerical ones show a small

  7. Non-whole beat correlation method for the identification of an unbalance response of a dual-rotor system with a slight rotating speed difference

    Science.gov (United States)

    Zhang, Z. X.; Wang, L. Z.; Jin, Z. J.; Zhang, Q.; Li, X. L.

    2013-08-01

    The efficient identification of the unbalanced responses in the inner and outer rotors from the beat vibration is the key step in the dynamic balancing of a dual-rotor system with a slight rotating speed difference. This paper proposes a non-whole beat correlation method to identify the unbalance responses whose integral time is shorter than the whole beat correlation method. The principle, algorithm and parameter selection of the proposed method is emphatically demonstrated in this paper. From the numerical simulation and balancing experiment conducted on horizontal decanter centrifuge, conclusions can be drawn that the proposed approach is feasible and practicable. This method makes important sense in developing the field balancing equipment based on portable Single Chip Microcomputer (SCMC) with low expense.

  8. Correlation between the time-series of air temperature and incident solar radiation at Port Harcourt, Nigeria

    International Nuclear Information System (INIS)

    Adjepong, S.K.; Okujagu, C.

    1987-12-01

    We present the preliminary results of an investigation of the correlation between the temporal variations of the time-series of ground air temperature and incident solar radiation recorded at Port Harcourt (lat. 4 deg. 51' N, long. 7 deg. 01' E), Nigeria, during a five-year period (1981 through 1985). Computed cross-correlation functions of the daily time-series reveal correlation at time lags which are approximate harmonics of the 27-day solar rotation cycle. The cross-correlation function of the mean monthly series shows correlation at a time lag of 12 months implying a dominant annual-cycle component in the variation of either series. (author). 12 refs, 2 figs

  9. Testing for time-based correlates of perceived gender discrimination.

    Science.gov (United States)

    Blau, Gary; Tatum, Donna Surges; Ward-Cook, Kory; Dobria, Lidia; McCoy, Keith

    2005-01-01

    Using a sample of 201 medical technologists (MTs) over a five-year period, this study extends initial findings on perceived gender discrimination (PGD) by Blau and Tatum (2000) by applying organizational justice variables and internal-external locus of control as hypothesized correlates of PGD. Three types of organizational justice were measured: distributive, procedural, and interactional. General relationships found include locus of control being related to PGD such that internals perceived lower PGD. Also, distributive, procedural, and interactional justice were negatively related to PGD. However, increasing the time interval between these correlates weakened their relationships. The relationship of interactional justice to PGD remained the most "resistant" to attenuation over time.

  10. Time delay correlations in chaotic scattering and random matrix approach

    International Nuclear Information System (INIS)

    Lehmann, N.; Savin, D.V.; Sokolov, V.V.; Sommers, H.J.

    1994-01-01

    We study the correlations in the time delay a model of chaotic resonance scattering based on the random matrix approach. Analytical formulae which are valid for arbitrary number of open channels and arbitrary coupling strength between resonances and channels are obtained by the supersymmetry method. The time delay correlation function, through being not a Lorentzian, is characterized, similar to that of the scattering matrix, by the gap between the cloud of complex poles of the S-matrix and the real energy axis. 28 refs.; 4 figs

  11. Correlation measure to detect time series distances, whence economy globalization

    Science.gov (United States)

    Miśkiewicz, Janusz; Ausloos, Marcel

    2008-11-01

    An instantaneous time series distance is defined through the equal time correlation coefficient. The idea is applied to the Gross Domestic Product (GDP) yearly increments of 21 rich countries between 1950 and 2005 in order to test the process of economic globalisation. Some data discussion is first presented to decide what (EKS, GK, or derived) GDP series should be studied. Distances are then calculated from the correlation coefficient values between pairs of series. The role of time averaging of the distances over finite size windows is discussed. Three network structures are next constructed based on the hierarchy of distances. It is shown that the mean distance between the most developed countries on several networks actually decreases in time, -which we consider as a proof of globalization. An empirical law is found for the evolution after 1990, similar to that found in flux creep. The optimal observation time window size is found ≃15 years.

  12. Image correlation spectroscopy: mapping correlations in space, time, and reciprocal space.

    Science.gov (United States)

    Wiseman, Paul W

    2013-01-01

    This chapter presents an overview of two recent implementations of image correlation spectroscopy (ICS). The background theory is presented for spatiotemporal image correlation spectroscopy and image cross-correlation spectroscopy (STICS and STICCS, respectively) as well as k-(reciprocal) space image correlation spectroscopy (kICS). An introduction to the background theory is followed by sections outlining procedural aspects for properly implementing STICS, STICCS, and kICS. These include microscopy image collection, sampling in space and time, sample and fluorescent probe requirements, signal to noise, and background considerations that are all required to properly implement the ICS methods. Finally, procedural steps for immobile population removal and actual implementation of the ICS analysis programs to fluorescence microscopy image time stacks are described. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Investigation of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting radial Growth on a Rotating Disk

    Science.gov (United States)

    Clem, Michelle M.; Woike, Mark R.

    2013-01-01

    The Aeronautical Sciences Project under NASA`s Fundamental Aeronautics Program is extremely interested in the development of novel measurement technologies, such as optical surface measurements in the internal parts of a flow path, for in situ health monitoring of gas turbine engines. In situ health monitoring has the potential to detect flaws, i.e. cracks in key components, such as engine turbine disks, before the flaws lead to catastrophic failure. In the present study, a cross-correlation imaging technique is investigated in a proof-of-concept study as a possible optical technique to measure the radial growth and strain field on an already cracked sub-scale turbine engine disk under loaded conditions in the NASA Glenn Research Center`s High Precision Rotordynamics Laboratory. The optical strain measurement technique under investigation offers potential fault detection using an applied high-contrast random speckle pattern and imaging the pattern under unloaded and loaded conditions with a CCD camera. Spinning the cracked disk at high speeds induces an external load, resulting in a radial growth of the disk of approximately 50.0-im in the flawed region and hence, a localized strain field. When imaging the cracked disk under static conditions, the disk will be undistorted; however, during rotation the cracked region will grow radially, thus causing the applied particle pattern to be .shifted`. The resulting particle displacements between the two images will then be measured using the two-dimensional cross-correlation algorithms implemented in standard Particle Image Velocimetry (PIV) software to track the disk growth, which facilitates calculation of the localized strain field. In order to develop and validate this optical strain measurement technique an initial proof-of-concept experiment is carried out in a controlled environment. Using PIV optimization principles and guidelines, three potential speckle patterns, for future use on the rotating disk, are developed

  14. Segmentation of time series with long-range fractal correlations

    Science.gov (United States)

    Bernaola-Galván, P.; Oliver, J.L.; Hackenberg, M.; Coronado, A.V.; Ivanov, P.Ch.; Carpena, P.

    2012-01-01

    Segmentation is a standard method of data analysis to identify change-points dividing a nonstationary time series into homogeneous segments. However, for long-range fractal correlated series, most of the segmentation techniques detect spurious change-points which are simply due to the heterogeneities induced by the correlations and not to real nonstationarities. To avoid this oversegmentation, we present a segmentation algorithm which takes as a reference for homogeneity, instead of a random i.i.d. series, a correlated series modeled by a fractional noise with the same degree of correlations as the series to be segmented. We apply our algorithm to artificial series with long-range correlations and show that it systematically detects only the change-points produced by real nonstationarities and not those created by the correlations of the signal. Further, we apply the method to the sequence of the long arm of human chromosome 21, which is known to have long-range fractal correlations. We obtain only three segments that clearly correspond to the three regions of different G + C composition revealed by means of a multi-scale wavelet plot. Similar results have been obtained when segmenting all human chromosome sequences, showing the existence of previously unknown huge compositional superstructures in the human genome. PMID:23645997

  15. Segmentation of time series with long-range fractal correlations.

    Science.gov (United States)

    Bernaola-Galván, P; Oliver, J L; Hackenberg, M; Coronado, A V; Ivanov, P Ch; Carpena, P

    2012-06-01

    Segmentation is a standard method of data analysis to identify change-points dividing a nonstationary time series into homogeneous segments. However, for long-range fractal correlated series, most of the segmentation techniques detect spurious change-points which are simply due to the heterogeneities induced by the correlations and not to real nonstationarities. To avoid this oversegmentation, we present a segmentation algorithm which takes as a reference for homogeneity, instead of a random i.i.d. series, a correlated series modeled by a fractional noise with the same degree of correlations as the series to be segmented. We apply our algorithm to artificial series with long-range correlations and show that it systematically detects only the change-points produced by real nonstationarities and not those created by the correlations of the signal. Further, we apply the method to the sequence of the long arm of human chromosome 21, which is known to have long-range fractal correlations. We obtain only three segments that clearly correspond to the three regions of different G + C composition revealed by means of a multi-scale wavelet plot. Similar results have been obtained when segmenting all human chromosome sequences, showing the existence of previously unknown huge compositional superstructures in the human genome.

  16. Implementation of a two-qubit controlled-rotation gate based on unconventional geometric phase with a constant gating time

    International Nuclear Information System (INIS)

    Yabu-uti, B.F.C.; Roversi, J.A.

    2011-01-01

    We propose an alternative scheme to implement a two-qubit controlled-R (rotation) gate in the hybrid atom-CCA (coupled cavities array) system. Our scheme results in a constant gating time and, with an adjustable qubit-bus coupling (atom-resonator), one can specify a particular rotation R on the target qubit. We believe that this proposal may open promising perspectives for networking quantum information processors and implementing distributed and scalable quantum computation. -- Highlights: → We propose an alternative two-qubit controlled-rotation gate implementation. → Our gate is realized in a constant gating time for any rotation. → A particular rotation on the target qubit can be specified by an adjustable qubit-bus coupling. → Our proposal may open promising perspectives for implementing distributed and scalable quantum computation.

  17. Palaeomagnetic Constrains on the Timing and the Geographical Distribution of Tectonic Rotations in the Betic Chain, Southern Spain. A Review

    Science.gov (United States)

    Osete, M. L.; Villalain, J. J.; Pavon-Carrasco, F. J.; Palencia, A.

    2009-05-01

    The Betic Cordillera is the northern branch of the Betic-Rifean orogen, the westernmost segment of the Mediterranean Alpine orogenic system. Several palaeomagnetic studies have enhanced the important role that block rotations about vertical axes have played in the tectonic evolution of the region. In this work we present a review of published palaeomagnetic data. According with the rotational deformation, the Betics are divided into the central-western area and the eastern Betics. A sequence of rotations for the two regions is also proposed. In central and western Subbetics almost constant clockwise rotations of about 60 are documented in Jurassic limestones. The existence of a pervasive remagnetization of Jurassic limestones, which was coeval with the folding of the studied units and dated as post-Palaeogene, constrains the timing of tectonic rotations in western Subbetics. New palaeomagnetic data from Neogene sedimentary sequences in central Betics indicate that palaeomagnetic clockwise rotations continued after late Miocene. A similar pattern of 40 CW rotations occurred after 20-17 Ma was obtained from the study of the Ronda-Malaga peridotites (western Internal Betics). In eastern Subbetics a more heterogeneous pattern, including very high CW rotations has been observed. But recent rotational deformation in the Internal part of eastern Betics is CCW and related to the left-lateral strike-slip fault systems. Proposed kinematics models for the Betics are discussed under the light of the present available palaeomagnetic information.

  18. Time correlation between mononucleosis and initial symptoms of MS

    Science.gov (United States)

    Endriz, John; Ho, Peggy P.

    2017-01-01

    Objective: To determine the average age of MS onset vs the age at which Epstein-Barr infection has previously occurred and stratify this analysis by sex and the blood level of Epstein-Barr nuclear antigen 1 (EBNA1) antibody. Methods: Using infectious mononucleosis (IM) as a temporal marker in data from the Swedish epidemiologic investigation of MS, 259 adult IM/MS cases were identified and then augmented to account for “missing” childhood data so that the average age of MS onset could be determined for cases binned by age of IM (as stratified by sex and EBNA1 titer level). Results: Mean age of IM vs mean age of MS reveals a positive time correlation for all IM ages (from ∼5 to ∼30 years), with IM-to-MS delay decreasing with increased age. When bifurcated by sex or EBNA1 blood titer levels, males and high-titer subpopulations show even stronger positive time correlation, while females and low-titer populations show negative time correlation in early childhood (long IM/MS delay). The correlation becomes positive in females beyond puberty. Conclusions: IM/MS time correlation implies causality if IM is time random. Alternative confounding models seem implausible, in light of constraints imposed by time-invariant delay observed here. Childhood infection with Epstein-Barr virus (EBV) in females and/or those genetically prone to low EBNA1 blood titers will develop MS slowly. Males and/or high EBNA1-prone develop MS more rapidly following IM infection at all ages. For all, postpubescent EBV infection is critical for the initiation and rapid development of MS. PMID:28271078

  19. Ultrafast time-resolved faraday rotation in EuO thin films.

    Science.gov (United States)

    Liu, F; Makino, T; Yamasaki, T; Ueno, K; Tsukazaki, A; Fukumura, T; Kong, Y; Kawasaki, M

    2012-06-22

    We have investigated the ultrafast spin dynamics in EuO thin films by time-resolved Faraday rotation spectroscopy. The photoinduced magnetization is found to be increased in a transient manner, accompanied with subsequent demagnetization. The dynamical magnetization enhancement showed a maximum slightly below the Curie temperature with prolonged tails toward both lower and higher temperatures and dominates the demagnetization counterpart at 55 K. The magnetization enhancement component decays in ~1 ns. The realization of the transient collective ordering is attributable to the enhancement of the f-d exchange interaction.

  20. Distribution of diffusion times determined by fluorescence (lifetime) correlation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Pánek, Jiří; Loukotová, Lenka; Hrubý, Martin; Štěpánek, Petr

    2018-01-01

    Roč. 51, č. 8 (2018), s. 2796-2804 ISSN 0024-9297 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : polymer solution * fluorescence correlation spectroscopy * diffusion time distribution Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 5.835, year: 2016

  1. Time correlation functions and transport coefficients in a dilute superfluid

    International Nuclear Information System (INIS)

    Kirkpatrick, T.R.; Dorfman, J.R.

    1985-01-01

    Time correlation functions for the transport coefficients in the linear Landau-Khalatnikov equations are derived on the basis of a formal theory. These Green--Kubo expressions are then explicitly evaluated for a dilute superfluid and the resulting transport coefficiencts are shown to be identical to those obtained previously by using a distribution function method

  2. Correlation and disorder-enhanced nematic spin response in superconductors with weakly broken rotational symmetry

    DEFF Research Database (Denmark)

    Andersen, Brian Møller; Graser, S.; Hirschfeld, P. J.

    2012-01-01

    Recent experimental and theoretical studies have highlighted the possible role of an electronic nematic liquid in underdoped cuprate superconductors. We calculate, within a model of d-wave superconductor with Hubbard correlations, the spin susceptibility in the case of a small explicitly broken...

  3. Correlation of visual performance with quality of life and intraocular aberrometric profile in patients implanted with rotationally asymmetric multifocal IOLs.

    Science.gov (United States)

    Ramón, María L; Piñero, David P; Pérez-Cambrodí, Rafael J

    2012-02-01

    To examine the visual performance of a rotationally asymmetric multifocal intraocular lens (IOL) by correlating the defocus curve of the IOL-implanted eye with the intraocular aberrometric profile and impact on the quality of life. A prospective, consecutive, case series study including 26 eyes from 13 patients aged between 50 and 83 years (mean: 65.54±7.59 years) was conducted. All patients underwent bilateral cataract surgery with implantation of a rotationally asymmetric multifocal IOL (Lentis Mplus LS-312 MF30, Oculentis GmbH). Distance and near visual acuity outcomes, intraocular aberrations, defocus curve, and quality of life (assessed using the National Eye Institute Visual Functioning Questionnaire-25) were evaluated postoperatively (mean follow-up: 6.42±2.24 months). A significant improvement in distance visual acuity was found postoperatively (P<.01). Mean postoperative logMAR distance-corrected near visual acuity was 0.19±0.12 (∼20/30). Corrected distance visual acuity and near visual acuity of 20/20 or better were achieved by 30.8% and 7.7% of eyes, respectively. Of all eyes, 96.2% had a postoperative addition between 0 and 1.00 diopter (D). The defocus curve showed two peaks of maximum visual acuity (0 and 3.00 D of defocus), with an acceptable range of intermediate vision. LogMAR visual acuity corresponding to near defocus was directly correlated with some higher order intraocular aberrations (r⩾0.44, P⩽.04). Some difficulties evaluated with the quality of life test correlated directly with near and intermediate visual acuity (r⩾0.50, P⩽.01). The Lentis Mplus multifocal IOL provides good distance, intermediate, and near visual outcomes; however, the induced intraocular aberrometric profile may limit the potential visual benefit. Copyright 2012, SLACK Incorporated.

  4. 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

  5. Excitation of Earth Rotation Variations "Observed" by Time-Variable Gravity

    Science.gov (United States)

    Chao, Ben F.; Cox, C. M.

    2005-01-01

    Time variable gravity measurements have been made over the past two decades using the space geodetic technique of satellite laser ranging, and more recently by the GRACE satellite mission with improved spatial resolutions. The degree-2 harmonic components of the time-variable gravity contain important information about the Earth s length-of-day and polar motion excitation functions, in a way independent to the traditional "direct" Earth rotation measurements made by, for example, the very-long-baseline interferometry and GPS. In particular, the (degree=2, order= 1) components give the mass term of the polar motion excitation; the (2,O) component, under certain mass conservation conditions, gives the mass term of the length-of-day excitation. Combining these with yet another independent source of angular momentum estimation calculated from global geophysical fluid models (for example the atmospheric angular momentum, in both mass and motion terms), in principle can lead to new insights into the dynamics, particularly the role or the lack thereof of the cores, in the excitation processes of the Earth rotation variations.

  6. Hawking fluxes and anomalies in rotating regular black holes with a time-delay

    International Nuclear Information System (INIS)

    Takeuchi, Shingo

    2016-01-01

    Based on the anomaly cancellation method we compute the Hawking fluxes (the Hawking thermal flux and the total flux of energy-momentum tensor) from a four-dimensional rotating regular black hole with a time-delay. To this purpose, in the three metrics proposed in [1], we try to perform the dimensional reduction in which the anomaly cancellation method is feasible at the near-horizon region in a general scalar field theory. As a result we can demonstrate that the dimensional reduction is possible in two of those metrics. Hence we perform the anomaly cancellation method and compute the Hawking fluxes in those two metrics. Our Hawking fluxes involve three effects: (1) quantum gravity effect regularizing the core of the black holes, (2) rotation of the black hole, (3) time-delay. Further in this paper toward the metric in which the dimensional could not be performed, we argue that it would be some problematic metric, and mention its cause. The Hawking fluxes we compute in this study could be considered to correspond to more realistic Hawking fluxes. Further what Hawking fluxes can be obtained from the anomaly cancellation method would be interesting in terms of the relation between a consistency of quantum field theories and black hole thermodynamics. (paper)

  7. Optimization of time-correlated single photon counting spectrometer

    International Nuclear Information System (INIS)

    Zhang Xiufeng; Du Haiying; Sun Jinsheng

    2011-01-01

    The paper proposes a performance improving scheme for the conventional time-correlated single photon counting spectrometer and develops a high speed data acquisition card based on PCI bus and FPGA technologies. The card is used to replace the multi-channel analyzer to improve the capability and decrease the volume of the spectrometer. The process of operation is introduced along with the integration of the spectrometer system. Many standard samples are measured. The experimental results show that the sensitivity of the spectrometer is single photon counting, and the time resolution of fluorescence lifetime measurement can be picosecond level. The instrument could measure the time-resolved spectroscopy. (authors)

  8. A distributed timing system for synchronizing control and data correlation

    International Nuclear Information System (INIS)

    Stettler, M.; Thuot, M.; Dalesio, L.R.; Cole, R.; Fite, C.; Slentz, G.; Warren, D.

    1992-01-01

    Synchronization is necessary in experimental physics machines to provide positive control over related events. The Ground Test Accelerator (GTA) timing system provides this function through a distributed control system, known as the Experimental Physics and Industrial Control System (EPICS). The EPICS timing system was designed to take advantage of a distributed architecture, and provides time stamping for synchronous data correlation as well as event control. The system has been successfully demonstrated on over a dozen controller nodes for operation and data analysis. The design of the hardware, software, and operational results are discussed. (author). 2 refs., 4 figs

  9. A distributed timing system for sychronizing control and data correlation

    International Nuclear Information System (INIS)

    Stettler, M.; Thout, M.; Dalesio, L.R.; Cole, R.; Fite, C.; Slentz, G.; Warren, D.

    1992-01-01

    Synchronization is necessary in experimental physics machines to provide positive control over related events. The Ground Test Accelerator (GTA) timing system provides this function through a distributed control system, known as the Experimental Physics and Industrial Control System (EPICS). The EPICS timing system was designed to take advantage of a distributed architecture, and provides time stamping for synchronous data correlation as well as event control. The system has been successfully demonstrated on over a dozen controller nodes for operation and data analysis. The design of the hardware, software, and operational results are discussed

  10. Multi-relaxation-time Lattice Boltzman model for uniform-shear flow over a rotating circular cylinder

    Directory of Open Access Journals (Sweden)

    Nemati Hasan

    2011-01-01

    Full Text Available A numerical investigation of the two-dimensional laminar flow and heat transfer a rotating circular cylinder with uniform planar shear, where the free-stream velocity varies linearly across the cylinder using Multi-Relaxation-Time Lattice Boltzmann method is conducted. The effects of variation of Reynolds number, rotational speed ratio at shear rate 0.1, blockage ratio 0.1 and Prandtl number 0.71 are studied. The Reynolds number changing from 50 to 160 for three rotational speed ratios of 0, 0.5, 1 is investigated. Results show that flow and heat transfer depends significantly on the rotational speed ratio as well as the Reynolds number. The effect of Reynolds number on the vortex-shedding frequency and period-surface Nusselt numbers is overall very strong compared with rotational speed ratio. Flow and heat conditions characteristics such as lift and drag coefficients, Strouhal number and Nusselt numbers are studied.

  11. Multivariate Option Pricing with Time Varying Volatility and Correlations

    DEFF Research Database (Denmark)

    Rombouts, Jeroen V.K.; Stentoft, Lars Peter

    In recent years multivariate models for asset returns have received much attention, in particular this is the case for models with time varying volatility. In this paper we consider models of this class and examine their potential when it comes to option pricing. Specifically, we derive the risk...... neutral dynamics for a general class of multivariate heteroskedastic models, and we provide a feasible way to price options in this framework. Our framework can be used irrespective of the assumed underlying distribution and dynamics, and it nests several important special cases. We provide an application...... to options on the minimum of two indices. Our results show that not only is correlation important for these options but so is allowing this correlation to be dynamic. Moreover, we show that for the general model exposure to correlation risk carries an important premium, and when this is neglected option...

  12. Extinction Time of a Metapopulation Driven by Colored Correlated Noises

    International Nuclear Information System (INIS)

    Li Jiangcheng

    2010-01-01

    The simplified incidence function model which is driven by the colored correlated noises is employed to investigate the extinction time of a metapopulation perturbed by environments. The approximate Fokker-Planck Equation and the mean first passage time which denotes the extinction time (T ex ) are obtained by virtue of the Novikov theorem and the Fox approach. After introducing a noise intensity ratio and a dimensionless parameter R = D/α (D and α are the multiplicative and additive colored noise intensities respectively), and then performing numerical computations, the results indicate that: (i) The absolute value of correlation strength Λ and its correlation time τ 3 play opposite roles on the T ex ; (ii) For the case of 0 2 play opposite roles on the T ex in which R > 1 is the best condition, and there is one-peak structure on the T ex - D plot; (iii) For the case of -1 1 play opposite roles on the T ex in which R ex - τ 2 plot. (general)

  13. Comparison of correlation analysis techniques for irregularly sampled time series

    Directory of Open Access Journals (Sweden)

    K. Rehfeld

    2011-06-01

    Full Text Available Geoscientific measurements often provide time series with irregular time sampling, requiring either data reconstruction (interpolation or sophisticated methods to handle irregular sampling. We compare the linear interpolation technique and different approaches for analyzing the correlation functions and persistence of irregularly sampled time series, as Lomb-Scargle Fourier transformation and kernel-based methods. In a thorough benchmark test we investigate the performance of these techniques.

    All methods have comparable root mean square errors (RMSEs for low skewness of the inter-observation time distribution. For high skewness, very irregular data, interpolation bias and RMSE increase strongly. We find a 40 % lower RMSE for the lag-1 autocorrelation function (ACF for the Gaussian kernel method vs. the linear interpolation scheme,in the analysis of highly irregular time series. For the cross correlation function (CCF the RMSE is then lower by 60 %. The application of the Lomb-Scargle technique gave results comparable to the kernel methods for the univariate, but poorer results in the bivariate case. Especially the high-frequency components of the signal, where classical methods show a strong bias in ACF and CCF magnitude, are preserved when using the kernel methods.

    We illustrate the performances of interpolation vs. Gaussian kernel method by applying both to paleo-data from four locations, reflecting late Holocene Asian monsoon variability as derived from speleothem δ18O measurements. Cross correlation results are similar for both methods, which we attribute to the long time scales of the common variability. The persistence time (memory is strongly overestimated when using the standard, interpolation-based, approach. Hence, the Gaussian kernel is a reliable and more robust estimator with significant advantages compared to other techniques and suitable for large scale application to paleo-data.

  14. Three-dimensional real-time synthetic aperture imaging using a rotating phased array transducer

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav; Dufait, Remi; Schoisswohl, Armin

    2002-01-01

    phased array, which is rotated over the volume of interest. The data is acquired using coded signals and synthetic transmit aperture imaging. Only one group of elements transmits at a time. The delays are set such as to form a cylindrical wave. The back-scattered signal carries information not only from......Current 3D real-time imaging is done either with sparse 2D arrays, or with mechanically moved phased arrays. The former results in a poor resolution and contrast due to a limited amount of elements. The latter has the disadvantage of low frame rates due to the sequential acquisition of the volume...... line-by-line and plane-by-plane. This paper describes an approach which combines mechanically moved phased array with synthetic transmit aperture imaging, resulting in high volume acquisition rates without a trade-off in image quality. The scan method uses a conventional fully populated 64 element...

  15. Russian State Time and Earth Rotation Service: Observations, Eop Series, Prediction

    Science.gov (United States)

    Kaufman, M.; Pasynok, S.

    2010-01-01

    Russian State Time, Frequency and Earth Rotation Service provides the official EOP data and time for use in scientific, technical and metrological works in Russia. The observations of GLONASS and GPS on 30 stations in Russia, and also the Russian and worldwide observations data of VLBI (35 stations) and SLR (20 stations) are used now. To these three series of EOP the data calculated in two other Russian analysis centers are added: IAA (VLBI, GPS and SLR series) and MCC (SLR). Joint processing of these 7 series is carried out every day (the operational EOP data for the last day and the predicted values for 50 days). The EOP values are weekly refined and systematic errors of every individual series are corrected. The combined results become accessible on the VNIIFTRI server (ftp.imvp.ru) approximately at 6h UT daily.

  16. Correlations between the geomagnetic field variations, the fluctuations of the earth`s rotation and climate change

    Energy Technology Data Exchange (ETDEWEB)

    Greiner-Mai, H; Jochmann, H

    1995-03-01

    The amplitude spectra of global geophysical phenomena were investigated to motivate research of physical connections between them. The suggested causality was derived from comparison of the spectra, and from cross correlation functions. The following global parameters were discussed: For the earth rotation by the variations of the length of day, for the geomagnetic variation by the global field intensity, changes of the dipole axis and the westward drift, and for climate change by the atmospheric excitation function derived from air pressure variations, and temperature variations. The model of atmospheric excitation, which can be proved most exactly for the annual variations of length of day, is responsible for the 11 and 22 years periods, too. It failed for longer periods, e.g. partially for the 30 years periods and completely for the 60 to 80 years periods, which were also discovered in the mean temperature and geomagnetic field variations. Therefore, it was suggested that longer periods in climate change and in the variations of the earth`s rotation are caused independently by the same process in the earth core, provided that a physical influence of the geomagnetic field on climate will be accepted in future. The investigation was completed by comparison with the spectra of some local temperature variations in Europe. (orig.)

  17. Long-time tails of correlation and memory functions

    Science.gov (United States)

    Sawada, Isao

    2002-11-01

    We review the generalized Langevin equation, which is a transformation and reformulation of equation of motion, from the two viewpoints: the projection operator method developed by Mori and the recurrence relations method developed by Lee. The fluctuating forces acting on the Bloch electrons’ current are clarified the strongly colored quantum fluctuations with the spontaneous interband transitions leading to a long-time tail of 1/ t for the envelope of the memory function. The velocity autocorrelation functions in the coupled harmonic oscillator on the Bethe lattice have a long-time tail of 1/t t. The oscillation and the form of decay found in correlation functions affect transport coefficients given by the integrated intensity up to infinity. We also study the force-force correlation functions often used as an approximation to the memory function.

  18. A new quantum statistical evaluation method for time correlation functions

    International Nuclear Information System (INIS)

    Loss, D.; Schoeller, H.

    1989-01-01

    Considering a system of N identical interacting particles, which obey Fermi-Dirac or Bose-Einstein statistics, the authors derive new formulas for correlation functions of the type C(t) = i= 1 N A i (t) Σ j=1 N B j > (where B j is diagonal in the free-particle states) in the thermodynamic limit. Thereby they apply and extend a superoperator formalism, recently developed for the derivation of long-time tails in semiclassical systems. As an illustrative application, the Boltzmann equation value of the time-integrated correlation function C(t) is derived in a straight-forward manner. Due to exchange effects, the obtained t-matrix and the resulting scattering cross section, which occurs in the Boltzmann collision operator, are now functionals of the Fermi-Dirac or Bose-Einstein distribution

  19. Progress of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting Radial Growth on a Rotating Disk

    Science.gov (United States)

    Clem, Michelle M.; Abdul-Aziz, Ali; Woike, Mark R.; Fralick, Gustave C.

    2015-01-01

    The modern turbine engine operates in a harsh environment at high speeds and is repeatedly exposed to combined high mechanical and thermal loads. The cumulative effects of these external forces lead to high stresses and strains on the engine components, such as the rotating turbine disks, which may eventually lead to a catastrophic failure if left undetected. The operating environment makes it difficult to use conventional strain gauges, therefore, non-contact strain measurement techniques is of interest to NASA and the turbine engine community. This presentation describes one such approach; the use of cross correlation analysis to measure strain experienced by the engine turbine disk with the goal of assessing potential faults and damage.

  20. Design of a real-time spectroscopic rotating compensator ellipsometer without systematic errors

    Energy Technology Data Exchange (ETDEWEB)

    Broch, Laurent, E-mail: laurent.broch@univ-lorraine.fr [Laboratoire de Chimie Physique-Approche Multi-echelle des Milieux Complexes (LCP-A2MC, EA 4632), Universite de Lorraine, 1 boulevard Arago CP 87811, F-57078 Metz Cedex 3 (France); Stein, Nicolas [Institut Jean Lamour, Universite de Lorraine, UMR 7198 CNRS, 1 boulevard Arago CP 87811, F-57078 Metz Cedex 3 (France); Zimmer, Alexandre [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary BP 47870, F-21078 Dijon Cedex (France); Battie, Yann; Naciri, Aotmane En [Laboratoire de Chimie Physique-Approche Multi-echelle des Milieux Complexes (LCP-A2MC, EA 4632), Universite de Lorraine, 1 boulevard Arago CP 87811, F-57078 Metz Cedex 3 (France)

    2014-11-28

    We describe a spectroscopic ellipsometer in the visible domain (400–800 nm) based on a rotating compensator technology using two detectors. The classical analyzer is replaced by a fixed Rochon birefringent beamsplitter which splits the incidence light wave into two perpendicularly polarized waves, one oriented at + 45° and the other one at − 45° according to the plane of incidence. Both emergent optical signals are analyzed by two identical CCD detectors which are synchronized by an optical encoder fixed on the shaft of the step-by-step motor of the compensator. The final spectrum is the result of the two averaged Ψ and Δ spectra acquired by both detectors. We show that Ψ and Δ spectra are acquired without systematic errors on a spectral range fixed from 400 to 800 nm. The acquisition time can be adjusted down to 25 ms. The setup was validated by monitoring the first steps of bismuth telluride film electrocrystallization. The results exhibit that induced experimental growth parameters, such as film thickness and volumic fraction of deposited material can be extracted with a better trueness. - Highlights: • High-speed rotating compensator ellipsometer equipped with 2 detectors. • Ellipsometric angles without systematic errors • In-situ monitoring of electrocrystallization of bismuth telluride thin layer • High-accuracy of fitted physical parameters.

  1. Estimating the implicit component of visuomotor rotation learning by constraining movement preparation time.

    Science.gov (United States)

    Leow, Li-Ann; Gunn, Reece; Marinovic, Welber; Carroll, Timothy J

    2017-08-01

    When sensory feedback is perturbed, accurate movement is restored by a combination of implicit processes and deliberate reaiming to strategically compensate for errors. Here, we directly compare two methods used previously to dissociate implicit from explicit learning on a trial-by-trial basis: 1 ) asking participants to report the direction that they aim their movements, and contrasting this with the directions of the target and the movement that they actually produce, and 2 ) manipulating movement preparation time. By instructing participants to reaim without a sensory perturbation, we show that reaiming is possible even with the shortest possible preparation times, particularly when targets are narrowly distributed. Nonetheless, reaiming is effortful and comes at the cost of increased variability, so we tested whether constraining preparation time is sufficient to suppress strategic reaiming during adaptation to visuomotor rotation with a broad target distribution. The rate and extent of error reduction under preparation time constraints were similar to estimates of implicit learning obtained from self-report without time pressure, suggesting that participants chose not to apply a reaiming strategy to correct visual errors under time pressure. Surprisingly, participants who reported aiming directions showed less implicit learning according to an alternative measure, obtained during trials performed without visual feedback. This suggests that the process of reporting can affect the extent or persistence of implicit learning. The data extend existing evidence that restricting preparation time can suppress explicit reaiming and provide an estimate of implicit visuomotor rotation learning that does not require participants to report their aiming directions. NEW & NOTEWORTHY During sensorimotor adaptation, implicit error-driven learning can be isolated from explicit strategy-driven reaiming by subtracting self-reported aiming directions from movement directions, or

  2. Factors impacting arthroscopic rotator cuff repair operational throughput time at an ambulatory care center

    Directory of Open Access Journals (Sweden)

    Emily J. Curry

    2018-03-01

    Full Text Available Identifying patient factors influencing operational throughput time is becoming more imperative due to an increasing focus on value and cost savings in healthcare. The primary objective of this study was to determine patient factors influencing throughput time for primary rotator cuff repairs. Demographic information, medical history and operative reports of 318 patients from one ambulatory care center were retrospectively reviewed. Operating room set up, incision to closure and recovery room time were collected from anesthesia records. Univariate analysis was performed for both continuous and categorical variables. A stepwise, multivariable regression analysis was performed to determine factors associated with operating room time (incision to closure and recovery room time. Of the 318 patients, the mean age was 54.4±10.0 and 197 (61% were male. Male patients had a significantly longer OR time than females (115.5 vs. 100.8 minutes; P<0.001. Furthermore, patients set up in the beach chair position had a significantly longer OR time than patients positioned lateral decubitus (115.8 vs. 89.6 mins, P<0.0001. Number of tendons involved, and inclusion of distal clavicle excision, biceps tenodesis and labral debridement also added significant OR time. Type and number of support staff present also significantly affected OR time. Recovery room time was significantly longer patients who had surgery in the beach chair position (+9.61 minutes and for those who had a cardiac-related medical comorbidity (+11.7 minutes. Our study found that patients positioned in a beach chair spent significantly more time in the operating and recovery rooms. While ease of set up has been a stated advantage ofbeach chair position, we found the perceived ease of set up does not result in more efficient OR throughput.

  3. Feasibility of real-time calculation of correlation integral derived statistics applied to EGG time series

    NARCIS (Netherlands)

    van den Broek, PLC; van Egmond, J; van Rijn, CM; Takens, F; Coenen, AML; Booij, LHDJ

    2005-01-01

    Background: This study assessed the feasibility of online calculation of the correlation integral (C(r)) aiming to apply C(r)derived statistics. For real-time application it is important to reduce calculation time. It is shown how our method works for EEG time series. Methods: To achieve online

  4. Feasibility of real-time calculation of correlation integral derived statistics applied to EEG time series

    NARCIS (Netherlands)

    Broek, P.L.C. van den; Egmond, J. van; Rijn, C.M. van; Takens, F.; Coenen, A.M.L.; Booij, L.H.D.J.

    2005-01-01

    This study assessed the feasibility of online calculation of the correlation integral (C(r)) aiming to apply C(r)-derived statistics. For real-time application it is important to reduce calculation time. It is shown how our method works for EEG time series. Methods: To achieve online calculation of

  5. Global rotation

    International Nuclear Information System (INIS)

    Rosquist, K.

    1980-01-01

    Global rotation in cosmological models is defined on an observational basis. A theorem is proved saying that, for rigid motion, the global rotation is equal to the ordinary local vorticity. The global rotation is calculated in the space-time homogeneous class III models, with Godel's model as a special case. It is shown that, with the exception of Godel's model, the rotation in these models becomes infinite for finite affine parameter values. In some directions the rotation changes sign and becomes infinite in a direction opposite to the local vorticity. The points of infinite rotation are identified as conjugate points along the null geodesics. The physical interpretation of the infinite rotation is discussed, and a comparison with the behaviour of the area distance at conjugate points is given. (author)

  6. Do the correlates of screen time and sedentary time differ in preschool children?

    Directory of Open Access Journals (Sweden)

    Katherine L Downing

    2017-03-01

    Full Text Available Abstract Background Preschool children can spend up to 12 h a day in sedentary time and few meet current recommendations for screen time. Little is known about ecological correlates that could be targeted to decrease specific versus total sedentary behaviour. This study examined whether the correlates of screen time and sedentary time differ in preschool boys and girls. Methods Parents participating in the HAPPY Study in 2008/09 in Melbourne, Australia reported their child’s usual screen time and potential individual, social and physical environment correlates. Children wore ActiGraph GT1M accelerometers for eight days to objectively assess sedentary time (<100 counts.min−1. Multivariable linear regression analyses were performed, stratified by sex and controlling for child age, preschool/childcare attendance and clustering by centre of recruitment. Correlates significantly associated with screen time or sedentary time in individual models (p < 0.05 were included in final combined models. Results Children were sedentary for 301.1 (SD 34.1 minutes/day and spent 108.5 (SD 69.6 minutes/day in screen time. There were no sex differences in screen or sedentary time. In the final models, sleep duration was inversely associated with girls’ sedentary time and boys’ screen time. The only other consistent correlates for boys and girls were parental self-efficacy to limit screen time and screen time rules, which were inversely associated with screen time for both sexes. Parents reporting that they get bored watching their child play was inversely associated and maternal television viewing was positively associated with boys’ screen time. Paternal age was positively associated with boys’ sedentary time. Maternal ethnicity was inversely associated and paternal education, child preferences for sedentary behaviour, and parental concerns about child’s physical activity and sedentary behaviour were positively associated with girls’ screen time

  7. Real-time Monitoring System for Rotating Machinery with IoT-based Cloud Platform

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Haedong; Kim, Suhyun; Woo, Sunhee; Kim, Songhyun; Lee, Seungchul [Ulsan Nat’l Institute Science and Technology, Ulsan (Korea, Republic of)

    2017-06-15

    The objective of this research is to improve the efficiency of data collection from many machine components on smart factory floors using IoT(Internet of things) techniques and cloud platform, and to make it easy to update outdated diagnostic schemes through online deployment methods from cloud resources. The short-term analysis is implemented by a micro-controller, and it includes machine-learning algorithms for inferring snapshot information of the machine components. For long-term analysis, time-series and high-dimension data are used for root cause analysis by combining a cloud platform and multivariate analysis techniques. The diagnostic results are visualized in a webbased display dashboard for an unconstrained user access. The implementation is demonstrated to identify its performance in data acquisition and analysis for rotating machinery.

  8. Hybrid state‐space time integration in a rotating frame of reference

    DEFF Research Database (Denmark)

    Krenk, Steen; Nielsen, Martin Bjerre

    2011-01-01

    displacements and the global velocities are represented by the same shape functions. This leads to a simple generalization of the corresponding equations of motion in a stationary frame in which all inertial effects are represented via the classic global mass matrix. The formulation introduces two gyroscopic......A time integration algorithm is developed for the equations of motion of a flexible body in a rotating frame of reference. The equations are formulated in a hybrid state‐space, formed by the local displacement components and the global velocity components. In the spatial discretization the local...... terms, while the centrifugal forces are represented implicitly via the hybrid state‐space format. An angular momentum and energy conserving algorithm is developed, in which the angular velocity of the frame is represented by its mean value. A consistent algorithmic damping scheme is identified...

  9. Real-time Monitoring System for Rotating Machinery with IoT-based Cloud Platform

    International Nuclear Information System (INIS)

    Jeong, Haedong; Kim, Suhyun; Woo, Sunhee; Kim, Songhyun; Lee, Seungchul

    2017-01-01

    The objective of this research is to improve the efficiency of data collection from many machine components on smart factory floors using IoT(Internet of things) techniques and cloud platform, and to make it easy to update outdated diagnostic schemes through online deployment methods from cloud resources. The short-term analysis is implemented by a micro-controller, and it includes machine-learning algorithms for inferring snapshot information of the machine components. For long-term analysis, time-series and high-dimension data are used for root cause analysis by combining a cloud platform and multivariate analysis techniques. The diagnostic results are visualized in a webbased display dashboard for an unconstrained user access. The implementation is demonstrated to identify its performance in data acquisition and analysis for rotating machinery.

  10. Rotation commensurate echo of asymmetric molecules—Molecular fingerprints in the time domain

    Energy Technology Data Exchange (ETDEWEB)

    Chesnokov, E. N., E-mail: chesnok@kinetics.nsc.ru [Institute of Chemical Kinetics and Combustion, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Kubarev, V. V. [Budker Institute of Nuclear Physics, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Koshlyakov, P. V. [Institute of Chemical Kinetics and Combustion, Novosibirsk 630090 (Russian Federation)

    2014-12-29

    Using the pulses of terahertz free electron laser and ultra-fast Schottky diode detectors, we observed the coherent transients within a free induction decay of gaseous nitrogen dioxide NO{sub 2}. The laser excited different sub-bands of rotation spectra of NO{sub 2} containing about 50–70 lines. The free induction signal continued more than 30 ns and consisted of many echo-like bursts duration about 0.2 ns. Unlike the similar effect observed previously for linear and symmetric top molecules, the sequence of echo bursts is not periodic. The values for delay of individual echo are stable, and the set of these delays can be considered as a “molecular fingerprint” in the time domain.

  11. Correlations of the chemical shift on fasly rotating biological solids by means of NMR spectroscopy; Korrelationen der chemischen Verschiebung an schnell rotierenden biologischen Festkoerpern mittels NMR-Spektroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, Christian

    2010-04-27

    The basic aim of the thesis was the development and improvement of homo- and heteronuclear feedback sequences for the generation of correlation spectra of the chemical shift. In a first step the possibility of the acquisition of {sup 13}C-{sup 13} correlation spectra of the chemical shift by means of inversion pulses with low RF power factor was studied. Furthermore it was shown that broad-band phase-modulated inversion and universal rotational pulses can be constructed by means of global optimization procedures like the genetic algorithms under regardment of the available RF field strength. By inversion, universal rotational, and 360 pulses as starting values of the optimization efficient homonuclear CN{sub n}{sup {nu}} and RN{sub n}{sup {nu}} mixing sequences as well as heteronuclear RN{sub n}{sup {nu}{sub s},{nu}{sub k}} feedback sequences were generated. The satisfactory power of the numerically optimized sequences was shown by means of the simulation as well by means of correlation experiments of the chemical shift of L-histidine, L-arginine, and the (CUG){sub 97}-RNA. This thesis deals furthermore with the possibility to acquire simultaneously different signals with several receivers. By means of numerically optimized RN{sub n}{sup {nu}{sub s},{nu}{sub k}} pulse sequences both {sup 15}N-{sup 13}C and {sup 13}C-{sup 15}N correlation spectra were simultaneously generated. Furthermore it could be shown that the simultaneous acquisition of 3D-{sup 15}N-{sup 13}C-{sup 13}C and {sup 13}C-{sup 15}N-({sup 1}H)-{sup 1}H correlation spectra is possible. By this in only one measurement process resonance assignments can be met and studies of the global folding performed. A further application of several receivers is the simultaneous acquisition of CHHC, NHHN, NHHC, as well as CHHN spectra. By such experiments it is possible to characterize the hydrogen-bonding pattern and the glycosidic torsion angle {sup {chi}} in RNA. This was demonstrated by means of the (CUG){sub 97

  12. Grayscale optical correlator for real-time onboard ATR

    Science.gov (United States)

    Chao, Tien-Hsin; Zhou, Hanying; Reyes, George F.

    2001-03-01

    Jet Propulsion Laboratory has been developing grayscale optical correlator (GOC) for a variety of automatic target recognition (ATR) applications. As reported in previous papers, a 128 X 128 camcorder-sized GOC has been demonstrated for real-time field ATR demos. In this paper, we will report the recent development of a prototype 512 X 512 GOC utilizing a new miniature ferroelectric liquid crystal spatial light modulator with a 7-micrometers pixel pitch. Experimental demonstration of ATR applications using this new GOC will be presented. The potential of developing a matchbox-sized GOC will also be discussed. A new application of synthesizing new complex-valued correlation filters using this real-axis 512 X 512 SLM will also be included.

  13. Correlation filtering in financial time series (Invited Paper)

    Science.gov (United States)

    Aste, T.; Di Matteo, Tiziana; Tumminello, M.; Mantegna, R. N.

    2005-05-01

    We apply a method to filter relevant information from the correlation coefficient matrix by extracting a network of relevant interactions. This method succeeds to generate networks with the same hierarchical structure of the Minimum Spanning Tree but containing a larger amount of links resulting in a richer network topology allowing loops and cliques. In Tumminello et al.,1 we have shown that this method, applied to a financial portfolio of 100 stocks in the USA equity markets, is pretty efficient in filtering relevant information about the clustering of the system and its hierarchical structure both on the whole system and within each cluster. In particular, we have found that triangular loops and 4 element cliques have important and significant relations with the market structure and properties. Here we apply this filtering procedure to the analysis of correlation in two different kind of interest rate time series (16 Eurodollars and 34 US interest rates).

  14. Nonequilibrium Physics at Short Time Scales: Formation of Correlations

    International Nuclear Information System (INIS)

    Peliti, L

    2005-01-01

    It is a happy situation when similar concepts and theoretical techniques can be applied to widely different physical systems because of a deep similarity in the situations being studied. The book illustrates this well; it focuses on the description of correlations in quantum systems out of equilibrium at very short time scales, prompted by experiments with short laser pulses in semiconductors, and in complex reactions in heavy nuclei. In both cases the experiments are characterized by nonlinear dynamics and by strong correlations out of equilibrium. In some systems there are also important finite-size effects. The book comprises several independent contributions of moderate length, and I sometimes felt that a more intensive effort in cross-coordination of the different contributions could have been of help. It is divided almost equally between theory and experiment. In the theoretical part, there is a thorough discussion both of the kinematic aspects (description of correlations) and the dynamical ones (evaluation of correlations). The experimental part is naturally divided according to the nature of the system: the interaction of pulsed lasers with matter on the one hand, and the correlations in finite-size systems (nanoparticles and nuclei) on the other. There is also a discussion on the dynamics of superconductors, a subject currently of great interest. Although an effort has been made to keep each contribution self-contained, I must admit that reading level is uneven. However, there are a number of thorough and stimulating contributions that make this book a useful introduction to the topic at the level of graduate students or researchers acquainted with quantum statistical mechanics. (book review)

  15. Advanced time-correlated single photon counting applications

    CERN Document Server

    Becker, Wolfgang

    2015-01-01

    This book is an attempt to bridge the gap between the instrumental principles of multi-dimensional time-correlated single photon counting (TCSPC) and typical applications of the technique. Written by an originator of the technique and by sucessful users, it covers the basic principles of the technique, its interaction with optical imaging methods and its application to a wide range of experimental tasks in life sciences and clinical research. The book is recommended for all users of time-resolved detection techniques in biology, bio-chemistry, spectroscopy of live systems, live cell microscopy, clinical imaging, spectroscopy of single molecules, and other applications that require the detection of low-level light signals at single-photon sensitivity and picosecond time resolution.

  16. A Novel Adaptive Joint Time Frequency Algorithm by the Neural Network for the ISAR Rotational Compensation

    Directory of Open Access Journals (Sweden)

    Zisheng Wang

    2018-02-01

    Full Text Available We propose a novel adaptive joint time frequency algorithm combined with the neural network (AJTF-NN to focus the distorted inverse synthetic aperture radar (ISAR image. In this paper, a coefficient estimator based on the artificial neural network (ANN is firstly developed to solve the time-consuming rotational motion compensation (RMC polynomial phase coefficient estimation problem. The training method, the cost function and the structure of ANN are comprehensively discussed. In addition, we originally propose a method to generate training dataset sourcing from the ISAR signal models with randomly chosen motion characteristics. Then, prediction results of the ANN estimator is used to directly compensate the ISAR image, or to provide a more accurate initial searching range to the AJTF for possible low-performance scenarios. Finally, some simulation models including the ideal point scatterers and a realistic Airbus A380 are employed to comprehensively investigate properties of the AJTF-NN, such as the stability and the efficiency under different signal-to-noise ratios (SNRs. Results show that the proposed method is much faster than other prevalent improved searching methods, the acceleration ratio are even up to 424 times without the deterioration of compensated image quality. Therefore, the proposed method is potential to the real-time application in the RMC problem of the ISAR imaging.

  17. The correlation between urinary 5-hydroxyindoleacetic acid and sperm quality in infertile men and rotating shift workers.

    Science.gov (United States)

    Ortiz, Águeda; Espino, Javier; Bejarano, Ignacio; Lozano, Graciela M; Monllor, Fabián; García, Juan F; Pariente, José A; Rodríguez, Ana B

    2010-11-08

    Serotonin is a neurotransmitter that modulates a wide range of neuroendocrine functions. However, excessive circulating serotonin levels may induce harmful effects in the male reproductive system. The objective of this study was to evaluate whether the levels of urinary 5-hydroxyindoleacetic acid (5-HIIA), a major serotonin metabolite, correlate with different classical seminal parameters. Human ejaculates were obtained from 40 men attending infertility counselling and rotating shift workers by masturbation after 4-5 days of abstinence. Urinary 5- HIIA concentration was quantified by using a commercial ELISA kit. Forward motility was assessed by a computer-aided semen analysis (CASA) system. Sperm concentration was determined using the haemocytometer method. Sperm morphology was evaluated after Diff-Quik staining, while sperm vitality was estimated after Eosin-Nigrosin vital staining. Our results show that urinary 5-HIIA levels obtained from a set of 20 volunteers negatively correlated with sperm concentration, forward motility, morphology normal range and sperm vitality. On the other hand, we checked the relationship between male infertility and urinary 5-HIIA levels in 20 night shift workers. Thus, urinary 5-HIIA levels obtained from 10 recently-proven fathers were significantly lower than those found in 10 infertile males. Additionally, samples from recent fathers exhibited higher sperm concentration, as well as better forward motility and normal morphology rate. In the light of our findings, we concluded that high serotonin levels, indirectly measured as urinary 5-HIIA levels, appear to play a role as an infertility determinant in male subjects.

  18. Some measurements of time and space correlation in wind tunnel

    Science.gov (United States)

    Favre, A; Gaviglio, J; Dumas, R

    1955-01-01

    Results are presented of research obtained by means of an apparatus for measurement of time and space correlation and of a spectral analyzer in the study of the longitudinal component of turbulence velocities in a wind tunnel downstream of a grid of meshes. Application to the case of a flat-plate boundary layer is illustrated. These researches were made at the Laboratoire de Mecanique de l'Atmosphere de l'I.M.F.M. for the O.N.E.R.A.

  19. Correlates of First-Time Mothers' Postpartum Stress

    Directory of Open Access Journals (Sweden)

    Chich-Hsiu Hung

    2006-10-01

    Full Text Available The purpose of this study was to examine first-time mothers' postpartum stress and its correlates following discharge from the hospital or clinic after vaginal delivery. One hundred and eightythree first-time mothers were enrolled from hospitals and clinics in Kaohsiung City. All first-time mothers reported normal pregnancies and vaginal deliveries, delivered healthy infants at term, and were surveyed during their postpartum periods after discharge from hospitals or clinics. The Hung Postpartum Stress Scale was used to examine first-time mothers' postpartum stress and stressors during their postpartum periods. The top ten postpartum stressors perceived by the women were: “the baby getting sick suddenly”, “the flabby flesh of my belly”, “the unpredictability of the baby's schedule”, “interrupted sleep”, “the shape of the baby's head due to the sleeping position”, “not sleeping enough”, “lack of information regarding infant's growth and development”, “the baby's crying”, “my life is restricted”, and “the baby choking during feeding”. There were no significant differences between the first-time mothers' demographic characteristics and their postpartum stress and its three components (negative body changes, maternal role attainment, lack of social support, respectively. Insight into the study results of first-time mothers' post- partum stress and stressors provides a reference for health professionals that the development of programs and resources addressing primiparous women's unique needs are required.

  20. Precise timing correlation in telemetry recording and processing systems

    Science.gov (United States)

    Pickett, R. B.; Matthews, F. L.

    1973-01-01

    Independent PCM telemetry data signals received from missiles must be correlated to within + or - 100 microseconds for comparison with radar data. Tests have been conducted to determine RF antenna receiving system delays; delays associated with wideband analog tape recorders used in the recording, dubbing and repdocuing processes; and uncertainties associated with computer processed time tag data. Several methods used in the recording of timing are evaluated. Through the application of a special time tagging technique, the cumulative timing bias from all sources is determined and the bias removed from final data. Conclusions show that relative time differences in receiving, recording, playback and processing of two telemetry links can be accomplished with a + or - 4 microseconds accuracy. In addition, the absolute time tag error (with respect to UTC) can be reduced to less than 15 microseconds. This investigation is believed to be the first attempt to identify the individual error contributions within the telemetry system and to describe the methods of error reduction within the telemetry system and to describe the methods of error reduction and correction.

  1. Communication: importance sampling including path correlation in semiclassical initial value representation calculations for time correlation functions.

    Science.gov (United States)

    Pan, Feng; Tao, Guohua

    2013-03-07

    Full semiclassical (SC) initial value representation (IVR) for time correlation functions involves a double phase space average over a set of two phase points, each of which evolves along a classical path. Conventionally, the two initial phase points are sampled independently for all degrees of freedom (DOF) in the Monte Carlo procedure. Here, we present an efficient importance sampling scheme by including the path correlation between the two initial phase points for the bath DOF, which greatly improves the performance of the SC-IVR calculations for large molecular systems. Satisfactory convergence in the study of quantum coherence in vibrational relaxation has been achieved for a benchmark system-bath model with up to 21 DOF.

  2. Wavelet Denoising of Radio Observations of Rotating Radio Transients (RRATs): Improved Timing Parameters for Eight RRATs

    Science.gov (United States)

    Jiang, M.; Cui, B.-Y.; Schmid, N. A.; McLaughlin, M. A.; Cao, Z.-C.

    2017-09-01

    Rotating radio transients (RRATs) are sporadically emitting pulsars detectable only through searches for single pulses. While over 100 RRATs have been detected, only a small fraction (roughly 20%) have phase-connected timing solutions, which are critical for determining how they relate to other neutron star populations. Detecting more pulses in order to achieve solutions is key to understanding their physical nature. Astronomical signals collected by radio telescopes contain noise from many sources, making the detection of weak pulses difficult. Applying a denoising method to raw time series prior to performing a single-pulse search typically leads to a more accurate estimation of their times of arrival (TOAs). Taking into account some features of RRAT pulses and noise, we present a denoising method based on wavelet data analysis, an image-processing technique. Assuming that the spin period of an RRAT is known, we estimate the frequency spectrum components contributing to the composition of RRAT pulses. This allows us to suppress the noise, which contributes to other frequencies. We apply the wavelet denoising method including selective wavelet reconstruction and wavelet shrinkage to the de-dispersed time series of eight RRATs with existing timing solutions. The signal-to-noise ratio (S/N) of most pulses are improved after wavelet denoising. Compared to the conventional approach, we measure 12%–69% more TOAs for the eight RRATs. The new timing solutions for the eight RRATs show 16%–90% smaller estimation error of most parameters. Thus, we conclude that wavelet analysis is an effective tool for denoising RRATs signal.

  3. Wavelet Denoising of Radio Observations of Rotating Radio Transients (RRATs): Improved Timing Parameters for Eight RRATs

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, M.; Schmid, N. A.; Cao, Z.-C. [Lane Department of Computer Science and Electrical Engineering West Virginia University Morgantown, WV 26506 (United States); Cui, B.-Y.; McLaughlin, M. A. [Department of Physics and Astronomy West Virginia University Morgantown, WV 26506 (United States)

    2017-09-20

    Rotating radio transients (RRATs) are sporadically emitting pulsars detectable only through searches for single pulses. While over 100 RRATs have been detected, only a small fraction (roughly 20%) have phase-connected timing solutions, which are critical for determining how they relate to other neutron star populations. Detecting more pulses in order to achieve solutions is key to understanding their physical nature. Astronomical signals collected by radio telescopes contain noise from many sources, making the detection of weak pulses difficult. Applying a denoising method to raw time series prior to performing a single-pulse search typically leads to a more accurate estimation of their times of arrival (TOAs). Taking into account some features of RRAT pulses and noise, we present a denoising method based on wavelet data analysis, an image-processing technique. Assuming that the spin period of an RRAT is known, we estimate the frequency spectrum components contributing to the composition of RRAT pulses. This allows us to suppress the noise, which contributes to other frequencies. We apply the wavelet denoising method including selective wavelet reconstruction and wavelet shrinkage to the de-dispersed time series of eight RRATs with existing timing solutions. The signal-to-noise ratio (S/N) of most pulses are improved after wavelet denoising. Compared to the conventional approach, we measure 12%–69% more TOAs for the eight RRATs. The new timing solutions for the eight RRATs show 16%–90% smaller estimation error of most parameters. Thus, we conclude that wavelet analysis is an effective tool for denoising RRATs signal.

  4. Real time implementation of the parametric imaging correlation algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Bogorodski, Piotr; Wolek, Tomasz; Wasielewski, Jaroslaw; Piatkowski, Adam [Medical and Nuclear Electronics Division, Institute of Radioelectronics, Warsaw University of Technology, 00-665 Warsaw, Nowowiejska 15/19 (Poland)

    1999-12-31

    A novel method for functional image evaluation from image set obtained in contrast aided Ultrafast Computed Tomography and Magnetic Resonance Imaging will be presented. The method converts temporal set of images of first-pass transit of injected contrast, to a single parametric image. The main difference between proposed procedure and other widely accepted methods is fast, that our method applies correlation and discrimination analysis to each concentration-time curve, instead of fitting them to the given a priori tracer kinetics model. A stress will be put on execution speed (i.e. shortening of the time required to obtain a perfusion relevant image), and easiest user interface allowing the physician to utilize the system without any technical assistance. Both execution speed and user interface should satisfy requirements in the interventional procedures. (authors)

  5. Time gated phase-correlation distributed Brillouin fibre sensor

    Science.gov (United States)

    Denisov, Andrey; Soto, Marcelo A.; Thévenaz, Luc

    2013-05-01

    A random access distributed Brillouin fibre sensor is presented, based on phase modulation using a pseudo-random bit sequence (PRBS) together with time gating. The standard phase-correlation technique is known to show a noise level increasing linearly with the number of measured points due to weak gratings generated randomly along the whole sensing fibre. Here we show how intensity modulated pump and time gated detection significantly improve the signal-tonoise ratio (SNR) of the system with no impact on the spatial resolution. A measurement with 1.1 cm spatial resolution over 3.3 km is demonstrated, representing 300'000 equivalent points. The limitations of the proposed technique are discussed through the paper.

  6. Correlated continuous time random walk and option pricing

    Science.gov (United States)

    Lv, Longjin; Xiao, Jianbin; Fan, Liangzhong; Ren, Fuyao

    2016-04-01

    In this paper, we study a correlated continuous time random walk (CCTRW) with averaged waiting time, whose probability density function (PDF) is proved to follow stretched Gaussian distribution. Then, we apply this process into option pricing problem. Supposing the price of the underlying is driven by this CCTRW, we find this model captures the subdiffusive characteristic of financial markets. By using the mean self-financing hedging strategy, we obtain the closed-form pricing formulas for a European option with and without transaction costs, respectively. At last, comparing the obtained model with the classical Black-Scholes model, we find the price obtained in this paper is higher than that obtained from the Black-Scholes model. A empirical analysis is also introduced to confirm the obtained results can fit the real data well.

  7. Time evolution of quenched state and correlation to glassy effects

    International Nuclear Information System (INIS)

    Kilic, K.; Kilic, A.; Altinkok, A.; Yetis, H.; Cetin, O.; Durust, Y.

    2005-01-01

    In this work, dynamic changes generated by the driving current were studied in superconducting bulk polycrystalline YBCO sample via transport relaxation measurements (V-t curves). The evolution of nonlinear V-t curves was interpreted in terms of the formation of resistive and nonresistive flow channels and the spatial reorganization of the transport current in a multiply connected network of weak-link structure. The dynamic re-organization of driving current could cause an enhancement or suppression in the superconducting order parameter due to the magnitude of the driving current and coupling strength of weak-link structure along with the chemical and anisotropic states of the sample as the time proceeds. A nonzero voltage decaying with time, correlated to the quenched state, was recorded when the magnitude of initial driving current is reduced to a finite value. It was found that, after sufficiently long waiting time, the evolution of the quenched state could result in a superconducting state, depending on the magnitude of the driving current and temperature. We showed that the decays in voltage over time are consistent with an exponential time dependence which is related to the glassy state. Further, the effect of doping of organic material Bis dimethyl-glyoximato Copper (II) to YBCO could be monitored apparently via the comparison of the V-t curves corresponding to doped and undoped YBCO samples

  8. Spatial- and Time-Correlated Detection of Fission Fragments

    Directory of Open Access Journals (Sweden)

    Platkevic M.

    2012-02-01

    Full Text Available With the goal to measure angular correlations of fission fragments in rare fission decay (e.g. ternary and quaternary fission, a multi-detector coincidence system based on two and up to four position sensitive pixel detectors Timepix has been built. In addition to the high granularity, wide dynamic range and per pixel signal threshold, these devices are equipped with per pixel energy and time sensitivity providing more information (position, energy, time, enhances particle-type identification and selectivity of event-by-event detection. Operation of the device with the integrated USB 2.0 based readout interface FITPix and the control and data acquisition software tool Pixelman enables online visualization and flexible/adjustable operation for a different type of experiments. Spatially correlated fission fragments can be thus registered in coincidence. Similarly triggered measurements are performed using an integrated spectrometric module with analogue signal chain electronics. The current status of development together with demonstration of the technique with a 252Cf source is presented.

  9. Using service-time profiles for distributed planning of container barge rotations along terminals

    NARCIS (Netherlands)

    Douma, A.M.; Schuur, Peter; Schutten, Johannes M.J.

    2008-01-01

    We consider the barge rotation planning and quay scheduling problem in the Port of Rotterdam. This problem concerns the alignment of barge rotations and terminal quay schedules. We use a Multi-Agent based approach for the problem, since such a Multi-Agent based system can mirror to a large extent

  10. Correlates of objectively measured sedentary time and self-reported screen time in Canadian children.

    Science.gov (United States)

    LeBlanc, Allana G; Broyles, Stephanie T; Chaput, Jean-Philippe; Leduc, Geneviève; Boyer, Charles; Borghese, Michael M; Tremblay, Mark S

    2015-03-18

    Demographic, family, and home characteristics play an important role in determining childhood sedentary behaviour. The objective of this paper was to identify correlates of total sedentary time (SED) and correlates of self-reported screen time (ST) in Canadian children. Child- and parent-reported household, socio-demographic, behavioural, and diet related data were collected; directly measured anthropometric and accelerometer data were also collected for each child. Participants with complete demographic, anthropometric, and either SED (n=524, 41% boys) or ST (n=567, 42% boys) data from the Canadian site of the International Study of Childhood Obesity Lifestyle and the Environment (ISCOLE) were included in analysis. Sixteen potential correlates of SED and ST were examined using multilevel general linear models, adjusting for sex, ethnicity, number of siblings, and socio-economic status. All explanatory variables moderately associated (peducation, and unhealthy eating pattern score and negatively associated with healthy eating pattern score, and weekend breakfast consumption. Few common correlates existed between boys and girls. Several factors were identified as correlates of SED and/or of ST in Canadian children; however, few correlates were common for both SED and ST, and for both boys and girls. This suggests that a single strategy to reduce SED and ST is unlikely to be effective. Future work should examine a variety of other, non-screen based sedentary behaviours and their potential correlates in the hopes of creating tailored public health messages to reduce SED and ST in both boys, and girls.

  11. Out-of-Time-Ordered Density Correlators in Luttinger Liquids.

    Science.gov (United States)

    Dóra, Balázs; Moessner, Roderich

    2017-07-14

    Information scrambling and the butterfly effect in chaotic quantum systems can be diagnosed by out-of-time-ordered (OTO) commutators through an exponential growth and large late time value. We show that the latter feature shows up in a strongly correlated many-body system, a Luttinger liquid, whose density fluctuations we study at long and short wavelengths, both in equilibrium and after a quantum quench. We find rich behavior combining robustly universal and nonuniversal features. The OTO commutators display temperature- and initial-state-independent behavior and grow as t^{2} for short times. For the short-wavelength density operator, they reach a sizable value after the light cone only in an interacting Luttinger liquid, where the bare excitations break up into collective modes. This challenges the common interpretation of the OTO commutator in chaotic systems. We benchmark our findings numerically on an interacting spinless fermion model in 1D and find persistence of central features even in the nonintegrable case. As a nonuniversal feature, the short-time growth exhibits a distance-dependent power.

  12. The correlation between urinary 5-hydroxyindoleacetic acid and sperm quality in infertile men and rotating shift workers

    Directory of Open Access Journals (Sweden)

    Pariente José A

    2010-11-01

    Full Text Available Abstract Background Serotonin is a neurotransmitter that modulates a wide range of neuroendocrine functions. However, excessive circulating serotonin levels may induce harmful effects in the male reproductive system. The objective of this study was to evaluate whether the levels of urinary 5-hydroxyindoleacetic acid (5-HIIA, a major serotonin metabolite, correlate with different classical seminal parameters. Methods Human ejaculates were obtained from 40 men attending infertility counselling and rotating shift workers by masturbation after 4-5 days of abstinence. Urinary 5- HIIA concentration was quantified by using a commercial ELISA kit. Forward motility was assessed by a computer-aided semen analysis (CASA system. Sperm concentration was determined using the haemocytometer method. Sperm morphology was evaluated after Diff-Quik staining, while sperm vitality was estimated after Eosin-Nigrosin vital staining. Results Our results show that urinary 5-HIIA levels obtained from a set of 20 volunteers negatively correlated with sperm concentration, forward motility, morphology normal range and sperm vitality. On the other hand, we checked the relationship between male infertility and urinary 5-HIIA levels in 20 night shift workers. Thus, urinary 5-HIIA levels obtained from 10 recently-proven fathers were significantly lower than those found in 10 infertile males. Additionally, samples from recent fathers exhibited higher sperm concentration, as well as better forward motility and normal morphology rate. Conclusions In the light of our findings, we concluded that high serotonin levels, indirectly measured as urinary 5-HIIA levels, appear to play a role as an infertility determinant in male subjects.

  13. Rotator cuff tears: correlation between geometric tear patterns on MRI and arthroscopy and pre- and postoperative clinical findings.

    Science.gov (United States)

    Sela, Yaron; Eshed, Iris; Shapira, Shachar; Oran, Ariel; Vogel, Guy; Herman, Amir; Perry Pritsch, Moshe

    2015-02-01

    Magnetic resonance imaging (MRI) is considered to be the best non-invasive procedure for the evaluation of rotator cuff (RC) tendon tears. Burkhart's classification is a geometric classification of full-thickness RC tears on MRI. To correlate MRI and arthroscopic geometric full-thickness RC tears according to the Burkhart's classification with pre- and postoperative clinical findings. Patients who underwent arthroscopic RC repair between 2006 and 2010 were retrospectively evaluated. Preoperative MRI and arthroscopic surgical reports were reviewed for tear geometry (Burkhart's) by three (1 radiologist, 2 surgeons) and two (surgeons) readers. MRIs were also evaluated for tear size and change of tear size in successive sagittal sections and for muscle mass and fatty infiltration. Clinical examinations were performed preoperatively and at least 12 months afterwards. Postoperative function questionnaires were filled in by the patients. Forty-six patients (35 men, 11 women; mean age, 57 years; range, 41-72 years) were evaluated. Tears depicted on MRIs were classified as crescent in 11 patients (24%), longitudinal in three (6.5%), massive contracted in 29 (63%), and cuff arthropathy in three (6.5%). Muscle changes were noted almost exclusively in patients with massive tears and cuff arthropathy (16/32 patients, P = 0.013). MRIs and arthroscopic geometric classifications were in close agreement. Tear type did not correlate with pre- and postoperative physical examination or with postoperative clinical questionnaires scores. Geometric RC tear characterizations on preoperative MRIs were closely associated with arthroscopic findings. Postoperative results were not affected by the geometric pattern of the tears. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  14. SU-E-I-60: The Correct Selection of Pitch and Rotation Time for Optimal CT Scanning : The Big Misconception

    International Nuclear Information System (INIS)

    Ranallo, F; Szczykutowicz, T

    2014-01-01

    Purpose: To provide correct guidance in the proper selection of pitch and rotation time for optimal CT imaging with multi-slice scanners. Methods: There exists a widespread misconception concerning the role of pitch in patient dose with modern multi-slice scanners, particularly with the use of mA modulation techniques. We investigated the relationship of pitch and rotation time to image quality, dose, and scan duration, with CT scanners from different manufacturers in a way that clarifies this misconception. This source of this misconception may concern the role of pitch in single slice CT scanners. Results: We found that the image noise and dose are generally independent of the selected effective mAs (mA*time/ pitch) with manual mA technique settings and are generally independent of the selected pitch and /or rotation time with automatic mA modulation techniques. However we did find that on certain scanners the use of a pitch just above 0.5 provided images of equal image noise at a lower dose compared to the use of a pitch just below 1.0. Conclusion: The misconception that the use of a lower pitch over-irradiates patients by wasting dose is clearly false. The use of a lower pitch provides images of equal or better image quality at the same patient dose, whether using manual mA or automatic mA modulation techniques. By decreasing the pitch and the rotation times by equal amounts, both helical and patient motion artifacts can be reduced without affecting the exam time. The use of lower helical pitch also allows better scanning of larger patients by allowing a greater scan effective mAs, if the exam time can be extended. The one caution with the use of low pitch is not related to patient dose, but to the length of the scan time if the rotation time is not set short enough. Partial Research funding from GE HealthCare

  15. Quasiprobability behind the out-of-time-ordered correlator

    Science.gov (United States)

    Yunger Halpern, Nicole; Swingle, Brian; Dressel, Justin

    2018-04-01

    Two topics, evolving rapidly in separate fields, were combined recently: the out-of-time-ordered correlator (OTOC) signals quantum-information scrambling in many-body systems. The Kirkwood-Dirac (KD) quasiprobability represents operators in quantum optics. The OTOC was shown to equal a moment of a summed quasiprobability [Yunger Halpern, Phys. Rev. A 95, 012120 (2017), 10.1103/PhysRevA.95.012120]. That quasiprobability, we argue, is an extension of the KD distribution. We explore the quasiprobability's structure from experimental, numerical, and theoretical perspectives. First, we simplify and analyze Yunger Halpern's weak-measurement and interference protocols for measuring the OTOC and its quasiprobability. We decrease, exponentially in system size, the number of trials required to infer the OTOC from weak measurements. We also construct a circuit for implementing the weak-measurement scheme. Next, we calculate the quasiprobability (after coarse graining) numerically and analytically: we simulate a transverse-field Ising model first. Then, we calculate the quasiprobability averaged over random circuits, which model chaotic dynamics. The quasiprobability, we find, distinguishes chaotic from integrable regimes. We observe nonclassical behaviors: the quasiprobability typically has negative components. It becomes nonreal in some regimes. The onset of scrambling breaks a symmetry that bifurcates the quasiprobability, as in classical-chaos pitchforks. Finally, we present mathematical properties. We define an extended KD quasiprobability that generalizes the KD distribution. The quasiprobability obeys a Bayes-type theorem, for example, that exponentially decreases the memory required to calculate weak values, in certain cases. A time-ordered correlator analogous to the OTOC, insensitive to quantum-information scrambling, depends on a quasiprobability closer to a classical probability. This work not only illuminates the OTOC's underpinnings, but also generalizes

  16. Time-dependent importance sampling in semiclassical initial value representation calculations for time correlation functions.

    Science.gov (United States)

    Tao, Guohua; Miller, William H

    2011-07-14

    An efficient time-dependent importance sampling method is developed for the Monte Carlo calculation of time correlation functions via the initial value representation (IVR) of semiclassical (SC) theory. A prefactor-free time-dependent sampling function weights the importance of a trajectory based on the magnitude of its contribution to the time correlation function, and global trial moves are used to facilitate the efficient sampling the phase space of initial conditions. The method can be generally applied to sampling rare events efficiently while avoiding being trapped in a local region of the phase space. Results presented in the paper for two system-bath models demonstrate the efficiency of this new importance sampling method for full SC-IVR calculations.

  17. Harmonic spectral components in time sequences of Markov correlated events

    Science.gov (United States)

    Mazzetti, Piero; Carbone, Anna

    2017-07-01

    The paper concerns the analysis of the conditions allowing time sequences of Markov correlated events give rise to a line power spectrum having a relevant physical interest. It is found that by specializing the Markov matrix in order to represent closed loop sequences of events with arbitrary distribution, generated in a steady physical condition, a large set of line spectra, covering all possible frequency values, is obtained. The amplitude of the spectral lines is given by a matrix equation based on a generalized Markov matrix involving the Fourier transform of the distribution functions representing the time intervals between successive events of the sequence. The paper is a complement of a previous work where a general expression for the continuous power spectrum was given. In that case the Markov matrix was left in a more general form, thus preventing the possibility of finding line spectra of physical interest. The present extension is also suggested by the interest of explaining the emergence of a broad set of waves found in the electro and magneto-encephalograms, whose frequency ranges from 0.5 to about 40Hz, in terms of the effects produced by chains of firing neurons within the complex neural network of the brain. An original model based on synchronized closed loop sequences of firing neurons is proposed, and a few numerical simulations are reported as an application of the above cited equation.

  18. Investigating the effect of a targets time-varying doppler generating axis of rotation on isar image distortion

    CSIR Research Space (South Africa)

    Abdul Gaffar, MY

    2007-10-01

    Full Text Available , contributes to ISAR image blurring. Quaternion algebra is used to aid the characterisation of a time-varying Doppler generating axis of rotation on the migration through cross-range cells. Real motion data of a sailing yacht is used to examine the effects of 3...

  19. Mid-rotation silviculture timing influences nitrogen mineralization of loblolly pine plantations in the mid-south USA

    Science.gov (United States)

    Michael A. Blazier; D. Andrew Scott; Ryan Coleman

    2015-01-01

    Intensively managed loblolly pine (Pinus taeda L.) plantations often develop nutrient deficiencies near mid-rotation. Common silvicultural treatments for improving stand nutrition at this stage include thinning, fertilization, and vegetation control. It is important to better understand the influence of timing fertilization and vegetation control...

  20. Correlation between the bending strength and the thickness interlayer of alumina-mild steel friction welded at lower rotational speed

    International Nuclear Information System (INIS)

    Mohamad Zaky Noh; Luay Bakir Hussain; Zainal Arifin Ahmad

    2007-01-01

    The joining of ceramic-metal could be done through a few techniques: brazing, diffusion bonding, friction welding etc. However, the mechanism of ceramic-metal joining was still not properly understood. In this study, alumina rod was bonded to mild steel rod via friction welding technique by using Al 1100 sheet as interlayer. The diameter of the rods was 10 mm. Friction pressure of 20 MPa and forging pressure of 40 MPa were used. Rotational speeds were maintained at 900 rpm and friction times of 2 to 20 seconds were applied. The joining strength was determined through four point bending test. The maximum bending strength, 240 MPa was obtained at the friction times of 20 seconds. Under optical microscope and SEM observation, the deformation of the aluminum interface was clearly obtained. Mechanical interlocking and close contact between the alumina aluminum and aluminum-mild steel were observed at magnifications of 3000X. The strength of alumina-steel bonding is much dependent on the wettability of the alumina surface by the molten aluminum and the existing of mechanical interlocking between interlayer and sample materials. (Author)

  1. HADES RV programme with HARPS-N at TNG. VII. Rotation and activity of M-dwarfs from time-series high-resolution spectroscopy of chromospheric indicators

    Science.gov (United States)

    Mascareño, A. Suárez; Rebolo, R.; González Hernández, J. I.; Toledo-Padrón, B.; Perger, M.; Ribas, I.; Affer, L.; Micela, G.; Damasso, M.; Maldonado, J.; González-Alvarez, E.; Leto, G.; Pagano, I.; Scandariato, G.; Sozzetti, A.; Lanza, A. F.; Malavolta, L.; Claudi, R.; Cosentino, R.; Desidera, S.; Giacobbe, P.; Maggio, A.; Rainer, M.; Esposito, M.; Benatti, S.; Pedani, M.; Morales, J. C.; Herrero, E.; Lafarga, M.; Rosich, A.; Pinamonti, M.

    2018-05-01

    We aim to investigate the presence of signatures of magnetic cycles and rotation on a sample of 71 early M-dwarfs from the HADES RV programme using high-resolution time-series spectroscopy of the Ca II H&K and Hα chromospheric activity indicators, the radial velocity series, the parameters of the cross correlation function and the V -band photometry. We used mainly HARPS-N spectra, acquired over 4 yr, and add HARPS spectra from the public ESO database and ASAS photometry light-curves as support data, extending the baseline of the observations of some stars up to 12 yr. We provide log10(R'HK) measurements for all the stars in the sample, cycle length measurements for 13 stars, rotation periods for 33 stars and we are able to measure the semi-amplitude of the radial velocity signal induced by rotation in 16 stars. We complement our work with previous results and confirm and refine the previously reported relationships between the mean level of chromospheric emission, measured by the log10(R'HK), with the rotation period, and with the measured semi-amplitude of the activity induced radial velocity signal for early M-dwarfs. We searched for a possible relation between the measured rotation periods and the lengths of the magnetic cycle, finding a weak correlation between both quantities. Using previous v sin i measurements we estimated the inclinations of the star's poles to the line of sight for all the stars in the sample, and estimate the range of masses of the planets GJ 3998 b and c (2.5-4.9 and 6.3-12.5 M⊕), GJ 625 b (2.82 M⊕), GJ 3942 b (7.1-10.0 M⊕) and GJ 15A b (3.1-3.3 M⊕), assuming their orbits are coplanar with the stellar rotation. Based on: observations made with the Italian Telescopio Nazionale Galileo (TNG), operated on the island of La Palma by the INAF - Fundación Galileo Galilei at the Roche de Los Muchachos Observatory of the Instituto de Astrofísica de Canarias (IAC); observations made with the HARPS instrument on the ESO 3.6-m telescope

  2. On the linearity of cross-correlation delay times

    Science.gov (United States)

    Mercerat, E. D.; Nolet, G.

    2012-12-01

    We investigate the question whether a P-wave delay time Δ T estimated by locating the maximum of the cross-correlation function between data d(t) and a predicted test function s(t): γ (t) = ∫ t1t_2 s(τ ) d(τ -t) \\ {d}τ, provides an estimate of the Delta T that is (quasi-)linear with the relative velocity perturbation deltaln V_P}. Such linearity is intuitive if the data d(t) is an undeformed but delayed replica of the test signal, i.e. if d(t)=s(t-Delta T). Then the maximum of gamma (t) is shifted exactly by the delay Delta T, and linearity holds even for Delta T very large. In this case, we say that the body waves are in the ray theoretical regime and their delays, because of Fermat's Principle, depend quasi-linearly on the relative velocity (or slowness) perturbations deltaln V_P in the model. However, even if we correct for dispersion induced by the instrument response and by attenuation, body waves may show frequency dependent delay times that are caused by diffraction effects around lateral heterogeneities. It is not a-priori clear that linearity holds for Delta T, as is assumed in finite-frequency theory, if the waveforms of d(t) and s(t) differ substantially because of such dispersion. To test the linearity, we generate synthetic seismograms between two boreholes, and between the boreholes and the surface, in a 3D box of 200 × 120 × 120 m. The heterogeneity is a checkerboard with cubic anomalies of size 12 × 12 × 12 m. We test two different anomaly amplitudes: ± 2% and ± 5%, and measure Delta T using a test seismogram s(t) computed for an homogeneous medium. We also predict the delays for the 5% model from those in the 2% model by multiplying with 5/2. These predictions are in error by 10-20% of the delay, which is usually acceptable for tomography when compared with actual data errors. A slight bias in the prediction indicates that the Wielandt effect - the fact that negative delays suffer less wavefront healing than positive delays - is a

  3. Magnetostrictive patch sensor system for battery-less real-time measurement of torsional vibrations of rotating shafts

    Science.gov (United States)

    Lee, Jun Kyu; Seung, Hong Min; Park, Chung Il; Lee, Joo Kyung; Lim, Do Hyeong; Kim, Yoon Young

    2018-02-01

    Real-time uninterrupted measurement for torsional vibrations of rotating shafts is crucial for permanent health monitoring. So far, strain gauge systems with telemetry units have been used for real-time monitoring. However, they have a critical disadvantage in that shaft operations must be stopped intermittently to replace telemetry unit batteries. To find an alternative method to carry out battery-less real-time measurement for torsional vibrations of rotating shafts, a magnetostrictive patch sensor system was proposed in the present study. Since the proposed sensor does not use any powered telemetry system, no battery is needed and thus there is no need to stop rotating shafts for battery replacement. The proposed sensor consists of magnetostrictive patches and small magnets tightly bonded onto a shaft. A solenoid coil is placed around the shaft to convert magnetostrictive patch deformation by shaft torsional vibration into electric voltage output. For sensor design and characterization, investigations were performed in a laboratory on relatively small-sized stationary solid shaft. A magnetostrictive patch sensor system was then designed and installed on a large rotating propulsion shaft of an LPG carrier ship in operation. Vibration signals were measured using the proposed sensor system and compared to those measured with a telemetry unit-equipped strain gauge system.

  4. Effect of time step size and turbulence model on the open water hydrodynamic performance prediction of contra-rotating propellers

    Science.gov (United States)

    Wang, Zhan-zhi; Xiong, Ying

    2013-04-01

    A growing interest has been devoted to the contra-rotating propellers (CRPs) due to their high propulsive efficiency, torque balance, low fuel consumption, low cavitations, low noise performance and low hull vibration. Compared with the single-screw system, it is more difficult for the open water performance prediction because forward and aft propellers interact with each other and generate a more complicated flow field around the CRPs system. The current work focuses on the open water performance prediction of contra-rotating propellers by RANS and sliding mesh method considering the effect of computational time step size and turbulence model. The validation study has been performed on two sets of contra-rotating propellers developed by David W Taylor Naval Ship R & D center. Compared with the experimental data, it shows that RANS with sliding mesh method and SST k-ω turbulence model has a good precision in the open water performance prediction of contra-rotating propellers, and small time step size can improve the level of accuracy for CRPs with the same blade number of forward and aft propellers, while a relatively large time step size is a better choice for CRPs with different blade numbers.

  5. Probing early-time correlations in heavy ion collisions

    International Nuclear Information System (INIS)

    Gavin, Sean; Moschelli, George

    2013-01-01

    We investigate the common influence of correlations arising from initial state parton density fluctuations on measured multiplicity and momentum fluctuations as well as flow fluctuations. We calculate both a universal correlation scale in an initial stage Glasma flux tube picture and the modification to these correlations from later stage hydrodynamic flow. We find quantitative agreement with measurements over a range of collision systems and energies.

  6. Correlation, regression, and cointegration of nonstationary economic time series

    DEFF Research Database (Denmark)

    Johansen, Søren

    Yule (1926) introduced the concept of spurious or nonsense correlation, and showed by simulation that for some nonstationary processes, that the empirical correlations seem not to converge in probability even if the processes were independent. This was later discussed by Granger and Newbold (1974......), and Phillips (1986) found the limit distributions. We propose to distinguish between empirical and population correlation coeffients and show in a bivariate autoregressive model for nonstationary variables that the empirical correlation and regression coe¢ cients do not converge to the relevant population...

  7. The effects of time, temperature and rotation of water on the corrosion rate of different types of steels

    International Nuclear Information System (INIS)

    Muhamad Daud; Jamaliah Shariff.

    1984-01-01

    By using hot plate/magnetic stirrer and immersion technique, the steel corroded uniformly and their corrosion rates vary due to type of steel, time of immersion, temperature and rotation of water. Therefore the rate of general corrosion, or sealing, of steel alloys is influenced by a number of factors, those best established being the composition of the metal, time, temperature, velocity, cleanliness or roughness of the metal surface and direct contact with solutions of the other materials. (author)

  8. Long-time correlations of periodic, area-preserving maps

    International Nuclear Information System (INIS)

    Meiss, J.D.; Cary, J.R.; Grebogi, C.; Crawford, J.D.; Kaufman, A.N.; Abarbanel, H.D.I.

    1982-04-01

    A simple analytical decay law for correlation functions of periodic, area-preserving maps is obtained. This law is compared with numerical experiments on the standard map. The agreement between experiment and theory is good when islands are absent, but poor when islands are present. When islands are present, the correlations have a long, slowly decaying tail

  9. Correlation, Regression, and Cointegration of Nonstationary Economic Time Series

    DEFF Research Database (Denmark)

    Johansen, Søren

    ), and Phillips (1986) found the limit distributions. We propose to distinguish between empirical and population correlation coefficients and show in a bivariate autoregressive model for nonstationary variables that the empirical correlation and regression coefficients do not converge to the relevant population...... values, due to the trending nature of the data. We conclude by giving a simple cointegration analysis of two interests. The analysis illustrates that much more insight can be gained about the dynamic behavior of the nonstationary variables then simply by calculating a correlation coefficient......Yule (1926) introduced the concept of spurious or nonsense correlation, and showed by simulation that for some nonstationary processes, that the empirical correlations seem not to converge in probability even if the processes were independent. This was later discussed by Granger and Newbold (1974...

  10. Dynamic Time-Resolved Chirped-Pulse Rotational Spectroscopy of Vinyl Cyanide Photoproducts in a Room Temperature Flow Reactor

    Science.gov (United States)

    Zaleski, Daniel P.; Prozument, Kirill

    2017-06-01

    Chirped-pulsed (CP) Fourier transform rotational spectroscopy invented by Brooks Pate and coworkers a decade ago is an attractive tool for gas phase chemical dynamics and kinetics studies. A good reactor for such a purpose would have well-defined (and variable) temperature and pressure conditions to be amenable to accurate kinetic modeling. Furthermore, in low pressure samples with large enough number of molecular emitters, reaction dynamics can be observable directly, rather than mediated by supersonic expansion. In the present work, we are evaluating feasibility of in situ time-resolved CP spectroscopy in a room temperature flow tube reactor. Vinyl cyanide (CH_2CHCN), neat or mixed with inert gasses, flows through the reactor at pressures 1-50 μbar (0.76-38 mTorr) where it is photodissociated by a 193 nm laser. Millimeter-wave beam of the CP spectrometer co-propagates with the laser beam along the reactor tube and interacts with nascent photoproducts. Rotational transitions of HCN, HNC, and HCCCN are detected, with ≥10 μs time-steps for 500 ms following photolysis of CH_2CHCN. The post-photolysis evolution of the photoproducts' rotational line intensities is investigated for the effects of rotational and vibrational thermalization of energized photoproducts. Possible contributions from bimolecular and wall-mediated chemistry are evaluated as well.

  11. Ultrafast time measurements by time-correlated single photon counting coupled with superconducting single photon detector

    Energy Technology Data Exchange (ETDEWEB)

    Shcheslavskiy, V., E-mail: vis@becker-hickl.de; Becker, W. [Becker & Hickl GmbH, Nahmitzer Damm 30, 12277 Berlin (Germany); Morozov, P.; Divochiy, A. [Scontel, Rossolimo St., 5/22-1, Moscow 119021 (Russian Federation); Vakhtomin, Yu. [Scontel, Rossolimo St., 5/22-1, Moscow 119021 (Russian Federation); Moscow State Pedagogical University, 1/1 M. Pirogovskaya St., Moscow 119991 (Russian Federation); Smirnov, K. [Scontel, Rossolimo St., 5/22-1, Moscow 119021 (Russian Federation); Moscow State Pedagogical University, 1/1 M. Pirogovskaya St., Moscow 119991 (Russian Federation); National Research University Higher School of Economics, 20 Myasnitskaya St., Moscow 101000 (Russian Federation)

    2016-05-15

    Time resolution is one of the main characteristics of the single photon detectors besides quantum efficiency and dark count rate. We demonstrate here an ultrafast time-correlated single photon counting (TCSPC) setup consisting of a newly developed single photon counting board SPC-150NX and a superconducting NbN single photon detector with a sensitive area of 7 × 7 μm. The combination delivers a record instrument response function with a full width at half maximum of 17.8 ps and system quantum efficiency ∼15% at wavelength of 1560 nm. A calculation of the root mean square value of the timing jitter for channels with counts more than 1% of the peak value yielded about 7.6 ps. The setup has also good timing stability of the detector–TCSPC board.

  12. Protected Time for Research During Orthopaedic Residency Correlates with an Increased Number of Resident Publications.

    Science.gov (United States)

    Williams, Benjamin R; Agel, Julie A; Van Heest, Ann E

    2017-07-05

    The Accreditation Council for Graduate Medical Education (ACGME) requires orthopaedic residency programs to promote scholarship and research, which manifest differently among programs. We assess the impact of protected research time during orthopaedic residency on the number of resident publications. Rotation schedules and resident names were collected from 125 ACGME-accredited U.S. orthopaedic residency programs. Protected research time was classified as 1 of 3 types: (1) block time, (2) longitudinal time, or (3) no dedicated time. In April 2016, we searched residents in postgraduate year (PGY)-3 to PGY-5 on pubmed.gov to generate all orthopaedic publications with a PubMed identifier published during residency. Each publication's 2015 Thomson Reuters Journal Citation Reports 5-Year Journal Impact Factor and resident first authorship were noted. The number of PubMed identifiers for each program was summed and was divided by the number of residents in PGY-3 to PGY-5, giving a mean number of publications per resident. The relationship between output and program research time was compared using t tests and analysis of variance (ANOVA). A total of 1,690 residents were included, with an overall mean number (and standard deviation) of 1.2 ± 2.4 publications per resident. Eighty-seven programs reported block time, 14 programs reported longitudinal time, and 24 programs reported no time. There was a significant difference (p = 0.02) in the mean number of publications per resident when compared between programs with protected time (1.1 ± 1.2 publications) and programs with no protected time (0.6 ± 0.5 publication). One-way ANOVA demonstrated a significant mean difference across the 3 groups (p publications than block time at 1.0 ± 1.0 publication or no time at 0.6 ± 0.5 publication, a difference that persisted when adjusted to include only impact factors of >0 and exclude case reports (p = 0.0015). Both the presence of and the type of dedicated research time correlate

  13. Detecting PM2.5's Correlations between Neighboring Cities Using a Time-Lagged Cross-Correlation Coefficient.

    Science.gov (United States)

    Wang, Fang; Wang, Lin; Chen, Yuming

    2017-08-31

    In order to investigate the time-dependent cross-correlations of fine particulate (PM2.5) series among neighboring cities in Northern China, in this paper, we propose a new cross-correlation coefficient, the time-lagged q-L dependent height crosscorrelation coefficient (denoted by p q (τ, L)), which incorporates the time-lag factor and the fluctuation amplitude information into the analogous height cross-correlation analysis coefficient. Numerical tests are performed to illustrate that the newly proposed coefficient ρ q (τ, L) can be used to detect cross-correlations between two series with time lags and to identify different range of fluctuations at which two series possess cross-correlations. Applying the new coefficient to analyze the time-dependent cross-correlations of PM2.5 series between Beijing and the three neighboring cities of Tianjin, Zhangjiakou, and Baoding, we find that time lags between the PM2.5 series with larger fluctuations are longer than those between PM2.5 series withsmaller fluctuations. Our analysis also shows that cross-correlations between the PM2.5 series of two neighboring cities are significant and the time lags between two PM2.5 series of neighboring cities are significantly non-zero. These findings providenew scientific support on the view that air pollution in neighboring cities can affect one another not simultaneously but with a time lag.

  14. Scale and time dependence of serial correlations in word-length time series of written texts

    Science.gov (United States)

    Rodriguez, E.; Aguilar-Cornejo, M.; Femat, R.; Alvarez-Ramirez, J.

    2014-11-01

    This work considered the quantitative analysis of large written texts. To this end, the text was converted into a time series by taking the sequence of word lengths. The detrended fluctuation analysis (DFA) was used for characterizing long-range serial correlations of the time series. To this end, the DFA was implemented within a rolling window framework for estimating the variations of correlations, quantified in terms of the scaling exponent, strength along the text. Also, a filtering derivative was used to compute the dependence of the scaling exponent relative to the scale. The analysis was applied to three famous English-written literary narrations; namely, Alice in Wonderland (by Lewis Carrol), Dracula (by Bram Stoker) and Sense and Sensibility (by Jane Austen). The results showed that high correlations appear for scales of about 50-200 words, suggesting that at these scales the text contains the stronger coherence. The scaling exponent was not constant along the text, showing important variations with apparent cyclical behavior. An interesting coincidence between the scaling exponent variations and changes in narrative units (e.g., chapters) was found. This suggests that the scaling exponent obtained from the DFA is able to detect changes in narration structure as expressed by the usage of words of different lengths.

  15. Progress of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting Radial Growth on a Rotating Disk

    Science.gov (United States)

    Clem, Michelle M.; Woike, Mark R.; Abdul-Aziz, Ali

    2014-01-01

    The Aeronautical Sciences Project under NASA's Fundamental Aeronautics Program is interested in the development of novel measurement technologies, such as optical surface measurements for the in situ health monitoring of critical constituents of the internal flow path. In situ health monitoring has the potential to detect flaws, i.e. cracks in key components, such as engine turbine disks, before the flaws lead to catastrophic failure. The present study, aims to further validate and develop an optical strain measurement technique to measure the radial growth and strain field of an already cracked disk, mimicking the geometry of a sub-scale turbine engine disk, under loaded conditions in the NASA Glenn Research Center's High Precision Rotordynamics Laboratory. The technique offers potential fault detection by imaging an applied high-contrast random speckle pattern under unloaded and loaded conditions with a CCD camera. Spinning the cracked disk at high speeds (loaded conditions) induces an external load, resulting in a radial growth of the disk of approximately 50.0-µm in the flawed region and hence, a localized strain field. When imaging the cracked disk under static conditions, the disk will be undistorted; however, during rotation the cracked region will grow radially, thus causing the applied particle pattern to be 'shifted'. The resulting particle displacements between the two images is measured using the two-dimensional cross-correlation algorithms implemented in standard Particle Image Velocimetry (PIV) software to track the disk growth, which facilitates calculation of the localized strain field. A random particle distribution is adhered onto the surface of the cracked disk and two bench top experiments are carried out to evaluate the technique's ability to measure the induced particle displacements. The disk is shifted manually using a translation stage equipped with a fine micrometer and a hotplate is used to induce thermal growth of the disk, causing the

  16. Locking of iridium magnetic moments to the correlated rotation of oxygen octahedra in Sr2IrO4 revealed by x-ray resonant scattering

    DEFF Research Database (Denmark)

    Boseggia, S.; Walker, H. C.; Vale, J.

    2013-01-01

    Sr2IrO4 is a prototype of the class of Mott insulators in the strong spin–orbit interaction (SOI) limit described by a Jeff = 1/2 ground state. In Sr2IrO4, the strong SOI is predicted to manifest itself in the locking of the canting of the magnetic moments to the correlated rotation by 11.8(1)° o...

  17. Identifiability analysis of rotational diffusion tensor and electronic transition moments measured in time-resolved fluorescence depolarization experiment

    International Nuclear Information System (INIS)

    Szubiakowski, Jacek P.

    2014-01-01

    The subject of this paper is studies of the deterministic identifiability of molecular parameters, such as rotational diffusion tensor components and orientation of electronic transition moments, resulting from the time-resolved fluorescence anisotropy experiment. In the most general case considered, a pair of perpendicularly polarized emissions enables the unique determination of all the rotational diffusion tensor's principal components. The influence of the tensor's symmetry and the associated degeneration of its eigenvalues on the identifiability of the electronic transitions moments is systematically investigated. The analysis reveals that independently of the rotational diffusion tensor's symmetry, the transition moments involved in photoselection and emission processes cannot be uniquely identified without a priori information about their mutual orientation or their orientation with respect to the principal axes of the tensor. Moreover, it is shown that increasing the symmetry of the rotational diffusion tensor deteriorates the degree of the transition moments identifiability. To obtain these results analytically, a novel approach to solve bilinear system of equations for Markov parameters is applied. The effect of the additional information, obtained from fluorescence measurements for different molecular mobilities, to improve the identifiability at various levels of analysis is shown. The effectiveness and reliability of the target analysis method for experimental determination of the molecular parameters is also discussed

  18. Correlation of financial markets in times of crisis

    Science.gov (United States)

    Sandoval, Leonidas; Franca, Italo De Paula

    2012-01-01

    Using the eigenvalues and eigenvectors of correlations matrices of some of the main financial market indices in the world, we show that high volatility of markets is directly linked with strong correlations between them. This means that markets tend to behave as one during great crashes. In order to do so, we investigate financial market crises that occurred in the years 1987 (Black Monday), 1998 (Russian crisis), 2001 (Burst of the dot-com bubble and September 11), and 2008 (Subprime Mortgage Crisis), which mark some of the largest downturns of financial markets in the last three decades.

  19. Evaluation of time correlation functions from a generalized Enskog equation

    Energy Technology Data Exchange (ETDEWEB)

    Yip, S.; Alley, W.E.; Alder, B.J.

    1982-01-01

    Numerical results for the density and current correlation functions in dense hard-shape fluids are obtained from a kinetic equation which is the extension of the linearized Enskog equation to finite wavelengths in order to demonstrate the convergence of the method of solution. Comparison is made to a previously proposed approximate solution.

  20. Evaluation of time correlation functions from a generalized Enskog equation

    International Nuclear Information System (INIS)

    Yip, S.; Alley, W.E.; Alder, B.J.

    1982-01-01

    Numerical results for the density and current correlation functions in dense hard-shape fluids are obtained from a kinetic equation which is the extension of the linearized Enskog equation to finite wavelengths in order to demonstrate the convergence of the method of solution. Comparison is made to a previously proposed approximate solution

  1. Correlates of time to microvascular complications among diabetes ...

    African Journals Online (AJOL)

    Socio-demographic and clinical factors have been known to affect the time to microvascular complications and survival probabilities of diabetes mellitus patients. The objective of this study was to identify risk factors and estimate average survival times for the time to the development of microvascular complications of ...

  2. Modeling long correlation times using additive binary Markov chains: Applications to wind generation time series.

    Science.gov (United States)

    Weber, Juliane; Zachow, Christopher; Witthaut, Dirk

    2018-03-01

    Wind power generation exhibits a strong temporal variability, which is crucial for system integration in highly renewable power systems. Different methods exist to simulate wind power generation but they often cannot represent the crucial temporal fluctuations properly. We apply the concept of additive binary Markov chains to model a wind generation time series consisting of two states: periods of high and low wind generation. The only input parameter for this model is the empirical autocorrelation function. The two-state model is readily extended to stochastically reproduce the actual generation per period. To evaluate the additive binary Markov chain method, we introduce a coarse model of the electric power system to derive backup and storage needs. We find that the temporal correlations of wind power generation, the backup need as a function of the storage capacity, and the resting time distribution of high and low wind events for different shares of wind generation can be reconstructed.

  3. Modeling long correlation times using additive binary Markov chains: Applications to wind generation time series

    Science.gov (United States)

    Weber, Juliane; Zachow, Christopher; Witthaut, Dirk

    2018-03-01

    Wind power generation exhibits a strong temporal variability, which is crucial for system integration in highly renewable power systems. Different methods exist to simulate wind power generation but they often cannot represent the crucial temporal fluctuations properly. We apply the concept of additive binary Markov chains to model a wind generation time series consisting of two states: periods of high and low wind generation. The only input parameter for this model is the empirical autocorrelation function. The two-state model is readily extended to stochastically reproduce the actual generation per period. To evaluate the additive binary Markov chain method, we introduce a coarse model of the electric power system to derive backup and storage needs. We find that the temporal correlations of wind power generation, the backup need as a function of the storage capacity, and the resting time distribution of high and low wind events for different shares of wind generation can be reconstructed.

  4. A variational determination of multi-time correlation functions

    International Nuclear Information System (INIS)

    Balian, R.

    1993-01-01

    The purpose of this course is to present the general features of a work recently achieved with Marcel Veneroni. Part of the methods and results were already published in previous articles, but a synthesis has now been made, and a coherent though flexible scheme for evaluating correlations has emerged. We shall illustrate the approach by an example which leads to an elaborate extension of the mean-field theory for interacting fermions. Application to finite temperatures field theories may also be considered. (author)

  5. Correlated initial condition for an embedded process by time partitioning

    Czech Academy of Sciences Publication Activity Database

    Velický, Bedřich; Kalvová, Anděla; Špička, Václav

    2010-01-01

    Roč. 81, č. 23 (2010), 235116/1-235116/12 ISSN 1098-0121 R&D Projects: GA ČR GA202/08/0361 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100521 Keywords : non-equilibrium * Initial conditions * decay of correlations * Green's functions * quantum transport equations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010

  6. Stationary axially symmetric perturbations of a rotating black hole. [Space-time perturbation, Newman-Penrose formalism

    Energy Technology Data Exchange (ETDEWEB)

    Demianski, M [California Inst. of Tech., Pasadena (USA)

    1976-07-01

    A stationary axially symmetric perturbation of a rotating black hole due to a distribution of test matter is investigated. The Newman-Penrose spin coefficient formalism is used to derive a general set of equations describing the perturbed space-time. In a linear approximation it is shown that the mass and angular momentum of a rotating black hole is not affected by the perturbation. The metric perturbations near the horizon are given. It is concluded that given a perturbing test fluid distribution, one can always find a corresponding metric perturbation such that the mass and angular momentum of the black hole are not changed. It was also noticed that when a tends to M, those perturbed spin coefficients and components of the Weyl tensor which determine the intrinsic properties of the incoming null cone near the horizon grow indefinitely.

  7. A 32-channel photon counting module with embedded auto/cross-correlators for real-time parallel fluorescence correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gong, S.; Labanca, I.; Rech, I.; Ghioni, M. [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-10-15

    Fluorescence correlation spectroscopy (FCS) is a well-established technique to study binding interactions or the diffusion of fluorescently labeled biomolecules in vitro and in vivo. Fast FCS experiments require parallel data acquisition and analysis which can be achieved by exploiting a multi-channel Single Photon Avalanche Diode (SPAD) array and a corresponding multi-input correlator. This paper reports a 32-channel FPGA based correlator able to perform 32 auto/cross-correlations simultaneously over a lag-time ranging from 10 ns up to 150 ms. The correlator is included in a 32 × 1 SPAD array module, providing a compact and flexible instrument for high throughput FCS experiments. However, some inherent features of SPAD arrays, namely afterpulsing and optical crosstalk effects, may introduce distortions in the measurement of auto- and cross-correlation functions. We investigated these limitations to assess their impact on the module and evaluate possible workarounds.

  8. A 32-channel photon counting module with embedded auto/cross-correlators for real-time parallel fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Gong, S.; Labanca, I.; Rech, I.; Ghioni, M.

    2014-01-01

    Fluorescence correlation spectroscopy (FCS) is a well-established technique to study binding interactions or the diffusion of fluorescently labeled biomolecules in vitro and in vivo. Fast FCS experiments require parallel data acquisition and analysis which can be achieved by exploiting a multi-channel Single Photon Avalanche Diode (SPAD) array and a corresponding multi-input correlator. This paper reports a 32-channel FPGA based correlator able to perform 32 auto/cross-correlations simultaneously over a lag-time ranging from 10 ns up to 150 ms. The correlator is included in a 32 × 1 SPAD array module, providing a compact and flexible instrument for high throughput FCS experiments. However, some inherent features of SPAD arrays, namely afterpulsing and optical crosstalk effects, may introduce distortions in the measurement of auto- and cross-correlation functions. We investigated these limitations to assess their impact on the module and evaluate possible workarounds

  9. Correlating defect density with growth time in continuous graphene films.

    Science.gov (United States)

    Kang, Cheong; Jung, Da Hee; Nam, Ji Eun; Lee, Jin Seok

    2014-12-01

    We report that graphene flakes and films which were synthesized by copper-catalyzed atmospheric pressure chemical vapor deposition (APCVD) method using a mixture of Ar, H2, and CH4 gases. It was found that variations in the reaction parameters, such as reaction temperature, annealing time, and growth time, influenced the domain size of as-grown graphene. Besides, the reaction parameters influenced the number of layers, degree of defects and uniformity of the graphene films. The increase in growth temperature and annealing time tends to accelerate the graphene growth rate and increase the diffusion length, respectively, thereby increasing the average size of graphene domains. In addition, we confirmed that the number of pinholes reduced with increase in the growth time. Micro-Raman analysis of the as-grown graphene films confirmed that the continuous graphene monolayer film with low defects and high uniformity could be obtained with prolonged reaction time, under the appropriate annealing time and growth temperature.

  10. The two-week pediatric surgery rotation: is it time wasted?

    Science.gov (United States)

    Dutta, S; Wales, P W; Fecteau, A

    2004-05-01

    With increasing medical school emphasis on generalist training and decreasing enrollment in surgical residency, the authors assessed the adequacy of a 2-week pediatric surgery rotation on meeting the learning and competency objectives outlined in The Canadian Association of Pediatric Surgeons' Self-Directed Evaluation Tool. A prospective survey was conducted of 39 clinical clerks. An anonymous self-assessment scale measuring competency objectives (medical and psychosocial) was administered pre-and postrotation. Also, exposure to pediatric surgical conditions from a list of "essential" and "nonessential" learning objectives was measured. Statistical analysis was performed using paired t test with significance at.05 level. Response rate was 77% and 54% for the competency and learning objectives, respectively. Students reported improvement in medical (P awareness of the breadth of pediatric surgical practice (P <.0001; 95% CI 2.06, 3.18). A 2-week rotation in pediatric surgery appears adequate in fulfilling most competency and learning objectives, but discussion is needed about how to best assess student competency, which topics are considered essential, and the long-term effect on recruitment to the profession.

  11. Thermocouple correlation transit time flowmeter tests at WCL

    International Nuclear Information System (INIS)

    Lassahn, G.D.

    1976-11-01

    Scoping tests indicate the feasibility for using transit time flowmeters with thermocouple sensors in steam-water steady state flow. Conclusive results were not obtained. More conclusive results are expected from tests to be conducted in the semiscale facility with a redesigned transit time thermocouple sensor

  12. Social cognitive correlates of leisure time physical activity among Latinos.

    Science.gov (United States)

    Marquez, David X; McAuley, Edward

    2006-06-01

    Despite the well-documented benefits of leisure time physical activity, Latinos are reported to be highest among all ethnic groups in leisure time inactivity. The present study examined the relationship between leisure time physical activity and exercise self-efficacy, exercise barriers self-efficacy, exercise social support, and perceived importance of physical activity. Data were obtained from 153 Latinos (n = 86 female, n = 67 male). Comparisons were made between Latinos with high and low levels of leisure time physical activity and between men and women. Results revealed that Latinos high in leisure time physical activity had significantly greater exercise and barriers self-efficacy, received more social support from friends to exercise, and placed greater importance on physical activity outcomes than did Latinos low in leisure time physical activity. No significant differences were revealed for social support from family, nor between men and women on the psychosocial variables. Physical activity interventions targeting sources of self-efficacy, increasing social support, and emphasizing the importance of regular physical activity should be helpful in increasing leisure time physical activity of Latinos. Future research should examine the influence of environmental and cultural variables on the leisure time physical activity of Latinos and how they interact with psychosocial factors.

  13. Groundwater travel time uncertainty analysis. Sensitivity of results to model geometry, and correlations and cross correlations among input parameters

    International Nuclear Information System (INIS)

    Clifton, P.M.

    1985-03-01

    This study examines the sensitivity of the travel time distribution predicted by a reference case model to (1) scale of representation of the model parameters, (2) size of the model domain, (3) correlation range of log-transmissivity, and (4) cross correlations between transmissivity and effective thickness. The basis for the reference model is the preliminary stochastic travel time model previously documented by the Basalt Waste Isolation Project. Results of this study show the following. The variability of the predicted travel times can be adequately represented when the ratio between the size of the zones used to represent the model parameters and the log-transmissivity correlation range is less than about one-fifth. The size of the model domain and the types of boundary conditions can have a strong impact on the distribution of travel times. Longer log-transmissivity correlation ranges cause larger variability in the predicted travel times. Positive cross correlation between transmissivity and effective thickness causes a decrease in the travel time variability. These results demonstrate the need for a sound conceptual model prior to conducting a stochastic travel time analysis

  14. Time evolution of some quantum-mechanical systems. Wavefunction cloning in evolving rotating systems. Finite range boundary conditions for time dependent Schroedinger Equation

    International Nuclear Information System (INIS)

    Arvieu, R.; Carbonell, J.; Gignoux, C.; Mangin-Brinet, M.; Rozmej, P.

    1997-01-01

    The time evolution of coherent rotational wave packets associated to a diatomic molecule or to a deformed nucleus has been studied. Assuming a rigid body dynamics the J(J+1) law leads to a mechanism of cloning: the way function is divided into wave packets identical to the initial one at specific time. Applications are studied for a nuclear wave packed formed by Coulomb excitation. Exact boundary conditions at finite distance for the solution of the time-dependent Schroedinger equation are derived. A numerical scheme based on Crank-Nicholson method is proposed to illustrate its applicability in several examples. (authors)

  15. Neural correlates of time versus money in product evaluation

    Directory of Open Access Journals (Sweden)

    Sebastian eLehmann

    2012-10-01

    Full Text Available The common saying time is money reflects the widespread belief in many people’s everyday life that time is valuable like money. Psychologically and neurophysiologically, however, these concepts seem to be quite different. This research replicates prior behavioral investigations by showing that merely mentioning time (compared to merely mentioning money leads participants to evaluate a product more positively. Beyond this finding, the present functional magnetic resonance imaging (fMRI experiment provides novel insight into the neurophysiological underpinnings of this behavioral effect by showing that more positive product evaluations in the time primes (compared to money primes are preceded by increased activation in the insula. Our data, therefore, support the idea of a time mindset that is different from a money mindset. Studies on the functional neuroanatomy of the insula have implicated this brain area in distinct but related psychological phenomena such as urging, addiction, loss aversion, and love. These functions imply greater personal connection between the consumer and a target subject or object and, thus, help explain why time-primed consumers rate products more positively.

  16. Brain microstructural correlates of visuospatial choice reaction time in children

    DEFF Research Database (Denmark)

    Madsen, Kathrine Skak; Baaré, William F C; Skimminge, Arnold

    2011-01-01

    The corticospinal tracts and the basal ganglia continue to develop during childhood and adolescence, and indices of their maturation can be obtained using diffusion-weighted imaging. Here we show that a simple measure of visuomotor function is correlated with diffusion parameters...... anisotropy (FA) in the corticospinal tracts, after controlling for age, gender, and handedness. Mean MD and/or FA were extracted from the right and left corticospinal tracts, putamen, and caudate nuclei. As predicted, faster 5-choice RTs were associated with lower MD in the corticospinal tracts, putamen......, and caudate. MD effects on RT were bilateral in the corticospinal tracts and putamen, whilst right caudate MD was more strongly related to performance than was left caudate MD. Our results suggest a link between motor performance variability in children and diffusivity in the motor system, which may...

  17. The generalized correlation method for estimation of time delay in power plants

    International Nuclear Information System (INIS)

    Kostic, Lj.

    1981-01-01

    The generalized correlation estimation is developed for determining time delay between signals received at two spatially separated sensors in the presence of uncorrelated noise in a power plant. This estimator can be realized as a pair of receiver prefilters followed by a cross correlator. The time argument at which the correlator achieves a maximum is the delay estimate. (author)

  18. Rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada

    Science.gov (United States)

    Rood, Dylan H.; Burbank, Douglas W.; Herman, Scott W.; Bogue, Scott

    2011-10-01

    We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. Samples from the Upper Miocene (˜9 Ma) Eureka Valley Tuff suggest clockwise vertical-axis block rotations between NE-striking left-lateral faults in the Bridgeport and Mono Basins. Results in the Bodie Hills suggest clockwise rotations (R ± ΔR, 95% confidence limits) of 74 ± 8° since Early to Middle Miocene (˜12-20 Ma), 42 ± 11° since Late Miocene (˜8-9 Ma), and 14 ± 10° since Pliocene (˜3 Ma) time with no detectable northward translation. The data are compatible with a relatively steady rotation rate of 5 ± 2° Ma-1 (2σ) since the Middle Miocene over the three examined timescales. The average rotation rates have probably not varied by more than a factor of two over time spans equal to half of the total time interval. Our paleomagnetic data suggest that block rotations in the region of the Mina Deflection began prior to Late Miocene time (˜9 Ma), and perhaps since the Middle Miocene if rotation rates were relatively constant. Block rotation in the Bodie Hills is similar in age and long-term average rate to rotations in the Transverse Ranges of southern California associated with early transtensional dextral shear deformation. We speculate that the age of rotations in the Bodie Hills indicates dextral shear and strain accommodation within the central Walker Lane Belt resulting from coupling of the Pacific and North America plates.

  19. Long-time tails of the heat-conductivity time correlation functions for a magnetized plasma - a kinetic theory approach

    NARCIS (Netherlands)

    Schoolderman, A.J.; Suttorp, L.G.

    1989-01-01

    The long-time behaviour of the longitudinal and the transverse heat conductivity time correlation functions for a magnetized one-component plasma is studied by means of kinetic theory. To that end these correlation functions, which are defined as the inverse Laplace transforms of the dynamic heat

  20. Time-Resolved PIV for Space-Time Correlations in Hot Jets

    Science.gov (United States)

    Wernet, Mark P.

    2007-01-01

    Temporally Resolved Particle Image Velocimetry (TR-PIV) is being used to characterize the decay of turbulence in jet flows a critical element for understanding the acoustic properties of the flow. A TR-PIV system, developed in-house at the NASA Glenn Research Center, is capable of acquiring planar PIV image frame pairs at up to 10 kHz. The data reported here were collected at Mach numbers of 0.5 and 0.9 and at temperature ratios of 0.89 and 1.76. The field of view of the TR-PIV system covered 6 nozzle diameters along the lip line of the 50.8 mm diameter jet. The cold flow data at Mach 0.5 were compared with hotwire anemometry measurements in order to validate the new TR-PIV technique. The axial turbulence profiles measured across the shear layer using TR-PIV were thinner than those measured using hotwire anemometry and remained centered along the nozzle lip line. The collected TR-PIV data illustrate the differences in the single point statistical flow properties of cold and hot jet flows. The planar, time-resolved velocity records were then used to compute two-point space-time correlations of the flow at the Mach 0.9 flow condition. The TR-PIV results show that there are differences in the convective velocity and growth rate of the turbulent structures between cold and hot flows at the same Mach number.

  1. Multicontextual correlates of adolescent leisure-time physical activity.

    Science.gov (United States)

    Graham, Dan J; Wall, Melanie M; Larson, Nicole; Neumark-Sztainer, Dianne

    2014-06-01

    Adolescent moderate to vigorous physical activity (MVPA) is influenced by many factors. MVPA-promotion interventions would fare better if these multiple determinants were better understood. To simultaneously assess overall and relative contributions of factors from personal, family, friend, school, and neighborhood contexts to adolescent MVPA. It was hypothesized that (1) key correlates would emerge in each context and (2) factors from more- versus less-proximal contexts would relate more strongly to MVPA. Students in grades 6-12 (n=2,793; mean age=14.4 [SD=2.0] years; 53% girls) were recruited from 20 Minnesota public schools in 2009-2010 to participate in the Eating and Activity in Teens 2010 study. Regression analyses conducted in 2013 examined factors related to weekly MVPA. Data were collected from adolescent participants, their parents and friends, school teachers and administrators, and GIS sources. Fifty multicontextual factors explained 25% of MVPA variance for boys and 27% for girls. Personal factors (e.g., self-efficacy) were most predictive of MVPA, followed by social factors (e.g., support for PA); environmental factors (e.g., access to PA resources) were least predictive of adolescent PA. Gender differences emerged for several predictors (e.g., in mutually adjusted analyses, MVPA among girls, but not boys, related positively to distance to trails and MVPA among female friends and fathers, and related negatively to perceived barriers). Stronger linkages exist between adolescent MVPA and more-proximal (personal, family, and friend) factors compared to more-distal (school and neighborhood) factors, suggesting the importance of working with adolescents, their families, and friends to promote PA. Copyright © 2014 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  2. Prospects of real-time ion temperature and rotation profiles based on neural-network charge exchange analysis

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, R W.T.; Von Hellermann, M [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Svensson, J [Royal Inst. of Tech., Stockholm (Sweden)

    1994-07-01

    A back-propagation neural network technique is used at JET to extract plasma parameters like ion temperature, rotation velocities or spectral line intensities from charge exchange (CX) spectra. It is shown that in the case of the C VI CX spectra, neural networks can give a good estimation (better than +-20% accuracy) for the main plasma parameters (Ti, V{sub rot}). Since the neural network approach involves no iterations or initial guesses the speed with which a spectrum is processed is so high (0.2 ms/spectrum) that real time analysis will be achieved in the near future. 4 refs., 8 figs.

  3. Prospects of real-time ion temperature and rotation profiles based on neural-network charge exchange analysis

    International Nuclear Information System (INIS)

    Koenig, R.W.T.; Von Hellermann, M.

    1994-01-01

    A back-propagation neural network technique is used at JET to extract plasma parameters like ion temperature, rotation velocities or spectral line intensities from charge exchange (CX) spectra. It is shown that in the case of the C VI CX spectra, neural networks can give a good estimation (better than +-20% accuracy) for the main plasma parameters (Ti, V rot ). Since the neural network approach involves no iterations or initial guesses the speed with which a spectrum is processed is so high (0.2 ms/spectrum) that real time analysis will be achieved in the near future. 4 refs., 8 figs

  4. Time-correlated neutron analysis of a multiplying HEU source

    International Nuclear Information System (INIS)

    Miller, E.C.; Kalter, J.M.; Lavelle, C.M.; Watson, S.M.; Kinlaw, M.T.; Chichester, D.L.; Noonan, W.A.

    2015-01-01

    The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated 3 He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations

  5. Time-correlated neutron analysis of a multiplying HEU source

    Energy Technology Data Exchange (ETDEWEB)

    Miller, E.C., E-mail: Eric.Miller@jhuapl.edu [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Kalter, J.M.; Lavelle, C.M. [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Watson, S.M.; Kinlaw, M.T.; Chichester, D.L. [Idaho National Laboratory, Idaho Falls, ID (United States); Noonan, W.A. [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States)

    2015-06-01

    The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated {sup 3}He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations.

  6. Time-correlated neutron analysis of a multiplying HEU source

    Science.gov (United States)

    Miller, E. C.; Kalter, J. M.; Lavelle, C. M.; Watson, S. M.; Kinlaw, M. T.; Chichester, D. L.; Noonan, W. A.

    2015-06-01

    The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated 3He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations.

  7. Third-order correlator for measuring the time profile of petawatt laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Ginzburg, V N; Lozhkarev, V V; Luchinin, G A; Mironov, S Yu; Khazanov, Efim A; Yakovlev, I V [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation); Didenko, N V; Konyashchenko, Aleksandr V; Lutsenko, Andrei P [' Avesta-project' Ltd., Troitsk, Moscow Region (Russian Federation)

    2008-11-30

    A third-order correlator with a single-shot time window and a full dynamic range of 10{sup 8} is developed. The time contrast of radiation from the front-end system of a petawatt femtosecond laser complex measured with the correlator within time windows {+-}1 ps and {+-}100 ps was 10{sup 4} and more than 10{sup 8}, respectively. Based on the theoretical analysis of the cross-correlator operation, a number of requirements providing the optimal functioning of the cross-correlator are found. The reasons restricting the technical parameters of the correlator are discussed. (measurement of parameters of laser radiation)

  8. Third-order correlator for measuring the time profile of petawatt laser pulses

    International Nuclear Information System (INIS)

    Ginzburg, V N; Lozhkarev, V V; Luchinin, G A; Mironov, S Yu; Khazanov, Efim A; Yakovlev, I V; Didenko, N V; Konyashchenko, Aleksandr V; Lutsenko, Andrei P

    2008-01-01

    A third-order correlator with a single-shot time window and a full dynamic range of 10 8 is developed. The time contrast of radiation from the front-end system of a petawatt femtosecond laser complex measured with the correlator within time windows ±1 ps and ±100 ps was 10 4 and more than 10 8 , respectively. Based on the theoretical analysis of the cross-correlator operation, a number of requirements providing the optimal functioning of the cross-correlator are found. The reasons restricting the technical parameters of the correlator are discussed. (measurement of parameters of laser radiation)

  9. Active method of neutron time correlation coincidence measurement to authenticate mass and enrichment of uranium metal

    International Nuclear Information System (INIS)

    Zhang Songbai; Wu Jun; Zhu Jianyu; Tian Dongfeng; Xie Dong

    2011-01-01

    The active methodology of time correlation coincidence measurement of neutron is an effective verification means to authenticate uranium metal. A collimated 252 Cf neutron source was used to investigate mass and enrichment of uranium metal through the neutron transport simulation for different enrichments and different masses of uranium metal, then time correlation coincidence counts of them were obtained. By analyzing the characteristic of time correlation coincidence counts, the monotone relationships were founded between FWTH of time correlation coincidence and multiplication factor, between the total coincidence counts in FWTH for time correlation coincidence and mass of 235 U multiplied by multiplication factor, and between the ratio of neutron source penetration and mass of uranium metal. Thus the methodology to authenticate mass and enrichment of uranium metal was established with time correlation coincidence by active neutron investigation. (authors)

  10. Shell model for time-correlated random advection of passive scalars

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Muratore-Ginanneschi, P.

    1999-01-01

    We study a minimal shell model for the advection of a passive scalar by a Gaussian time-correlated velocity field. The anomalous scaling properties of the white noise limit are studied analytically. The effect of the time correlations are investigated using perturbation theory around the white...... noise limit and nonperturbatively by numerical integration. The time correlation of the velocity field is seen to enhance the intermittency of the passive scalar. [S1063-651X(99)07711-9]....

  11. Time Resolved PIV for Space-Time Correlations in Hot Jets

    Science.gov (United States)

    Wernet, Mark P.

    2007-01-01

    Temporally Resolved Particle Image Velocimetry (TR-PIV) is the newest and most exciting tool recently developed to support our continuing efforts to characterize and improve our understanding of the decay of turbulence in jet flows -- a critical element for understanding the acoustic properties of the flow. A new TR-PIV system has been developed at the NASA Glenn Research Center which is capable of acquiring planar PIV image frame pairs at up to 25 kHz. The data reported here were collected at Mach numbers of 0.5 and 0.9 and at temperature ratios of 0.89 and 1.76. The field of view of the TR-PIV system covered 6 nozzle diameters along the lip line of the 50.8 mm diameter jet. The cold flow data at Mach 0.5 were compared with hotwire anemometry measurements in order to validate the new TR-PIV technique. The axial turbulence profiles measured across the shear layer using TR-PIV were thinner than those measured using hotwire anemometry and remained centered along the nozzle lip line. The collected TR-PIV data illustrate the differences in the single point statistical flow properties of cold and hot jet flows. The planar, time-resolved velocity records were then used to compute two-point space-time correlations of the flow at the Mach 0.9 flow condition. The TR-PIV results show that there are differences in the convective velocity and growth rate of the turbulent structures between cold and hot flows at the same Mach number

  12. Rotating preventers

    International Nuclear Information System (INIS)

    Tangedahl, M.J.; Stone, C.R.

    1992-01-01

    This paper reports that recent changes in the oil and gas industry and ongoing developments in horizontal and underbalanced drilling necessitated development of a better rotating head. A new device called the rotating blowout preventer (RBOP) was developed by Seal-Tech. It is designed to replace the conventional rotating control head on top of BOP stacks and allows drilling operations to continue even on live (underbalanced) wells. Its low wear characteristics and high working pressure (1,500 psi) allow drilling rig crews to drill safely in slightly underbalanced conditions or handle severe well control problems during the time required to actuate other BOPs in the stack. Drilling with a RBOP allows wellbores to be completely closed in tat the drill floor rather than open as with conventional BOPs

  13. Computation by symmetry operations in a structured model of the brain: Recognition of rotational invariance and time reversal

    Science.gov (United States)

    McGrann, John V.; Shaw, Gordon L.; Shenoy, Krishna V.; Leng, Xiaodan; Mathews, Robert B.

    1994-06-01

    Symmetries have long been recognized as a vital component of physical and biological systems. What we propose here is that symmetry operations are an important feature of higher brain function and result from the spatial and temporal modularity of the cortex. These symmetry operations arise naturally in the trion model of the cortex. The trion model is a highly structured mathematical realization of the Mountcastle organizational principle [Mountcastle, in The Mindful Brain (MIT, Cambridge, 1978)] in which the cortical column is the basic neural network of the cortex and is comprised of subunit minicolumns, which are idealized as trions with three levels of firing. A columnar network of a small number of trions has a large repertoire of quasistable, periodic spatial-temporal firing magic patterns (MP's), which can be excited. The MP's are related by specific symmetries: Spatial rotation, parity, ``spin'' reversal, and time reversal as well as other ``global'' symmetry operations in this abstract internal language of the brain. These MP's can be readily enhanced (as well as inherent categories of MP's) by only a small change in connection strengths via a Hebb learning rule. Learning introduces small breaking of the symmetries in the connectivities which enables a symmetry in the patterns to be recognized in the Monte Carlo evolution of the MP's. Examples of the recognition of rotational invariance and of a time-reversed pattern are presented. We propose the possibility of building a logic device from the hardware implementation of a higher level architecture of trion cortical columns.

  14. Rotating Arc Jet Test Model: Time-Accurate Trajectory Heat Flux Replication in a Ground Test Environment

    Science.gov (United States)

    Laub, Bernard; Grinstead, Jay; Dyakonov, Artem; Venkatapathy, Ethiraj

    2011-01-01

    Though arc jet testing has been the proven method employed for development testing and certification of TPS and TPS instrumentation, the operational aspects of arc jets limit testing to selected, but constant, conditions. Flight, on the other hand, produces timevarying entry conditions in which the heat flux increases, peaks, and recedes as a vehicle descends through an atmosphere. As a result, we are unable to "test as we fly." Attempts to replicate the time-dependent aerothermal environment of atmospheric entry by varying the arc jet facility operating conditions during a test have proven to be difficult, expensive, and only partially successful. A promising alternative is to rotate the test model exposed to a constant-condition arc jet flow to yield a time-varying test condition at a point on a test article (Fig. 1). The model shape and rotation rate can be engineered so that the heat flux at a point on the model replicates the predicted profile for a particular point on a flight vehicle. This simple concept will enable, for example, calibration of the TPS sensors on the Mars Science Laboratory (MSL) aeroshell for anticipated flight environments.

  15. Study of water flowrate using time transient and cross-correlation techniques with 82Br radiotracer

    International Nuclear Information System (INIS)

    Salgado, William L.; Brandao, Luiz E.B.

    2013-01-01

    This paper aims to determinate the water flowrate using Time Transient and Cross-Correlation techniques. The detection system uses two NaI (T1) detectors adequately positioned on the outside of pipe and a gamma-ray source ( 82 Br radiotracer). The water flowrate measurements using Time Transient and Cross-Correlation techniques were compared to invasive conventional measurements of the flowrate previously installed in pipeline. Discrepancies between Time Transient and Cross-Correlation techniques flowmeter previously installed in pipeline. Discrepancies between Time Transient and Cross-Correlation techniques flowrate values were found to be less than 3% in relation to conventional ones. (author)

  16. Earth Rotation

    Science.gov (United States)

    Dickey, Jean O.

    1995-01-01

    The study of the Earth's rotation in space (encompassing Universal Time (UT1), length of day, polar motion, and the phenomena of precession and nutation) addresses the complex nature of Earth orientation changes, the mechanisms of excitation of these changes and their geophysical implications in a broad variety of areas. In the absence of internal sources of energy or interactions with astronomical objects, the Earth would move as a rigid body with its various parts (the crust, mantle, inner and outer cores, atmosphere and oceans) rotating together at a constant fixed rate. In reality, the world is considerably more complicated, as is schematically illustrated. The rotation rate of the Earth's crust is not constant, but exhibits complicated fluctuations in speed amounting to several parts in 10(exp 8) [corresponding to a variation of several milliseconds (ms) in the Length Of the Day (LOD) and about one part in 10(exp 6) in the orientation of the rotation axis relative to the solid Earth's axis of figure (polar motion). These changes occur over a broad spectrum of time scales, ranging from hours to centuries and longer, reflecting the fact that they are produced by a wide variety of geophysical and astronomical processes. Geodetic observations of Earth rotation changes thus provide insights into the geophysical processes illustrated, which are often difficult to obtain by other means. In addition, these measurements are required for engineering purposes. Theoretical studies of Earth rotation variations are based on the application of Euler's dynamical equations to the problem of finding the response of slightly deformable solid Earth to variety of surface and internal stresses.

  17. A key role for experimental task performance: effects of math talent, gender and performance on the neural correlates of mental rotation.

    Science.gov (United States)

    Hoppe, Christian; Fliessbach, Klaus; Stausberg, Sven; Stojanovic, Jelena; Trautner, Peter; Elger, Christian E; Weber, Bernd

    2012-02-01

    The neurophysiological mechanisms underlying superior cognitive performance are a research area of high interest. The majority of studies on the brain-performance relationship assessed the effects of capability-related group factors (e.g. talent, gender) on task-related brain activations while only few studies examined the effect of the inherent experimental task performance factor. In this functional MRI study, we combined both approaches and simultaneously assessed the effects of three relatively independent factors on the neurofunctional correlates of mental rotation in same-aged adolescents: math talent (gifted/controls: 17/17), gender (male/female: 16/18) and experimental task performance (median split on accuracy; high/low: 17/17). Better experimental task performance of mathematically gifted vs. control subjects and male vs. female subjects validated the selected paradigm. Activation of the inferior parietal lobule (IPL) was identified as a common effect of mathematical giftedness, gender and experimental task performance. However, multiple linear regression analyses (stepwise) indicated experimental task performance as the only predictor of parietal activations. In conclusion, increased activation of the IPL represents a positive neural correlate of mental rotation performance, irrespective of but consistent with the obtained neurocognitive and behavioral effects of math talent and gender. As experimental performance may strongly affect task-related activations this factor needs to be considered in capability-related group comparison studies on the brain-performance relationship. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Groundwater travel time uncertainty analysis: Sensitivity of results to model geometry, and correlations and cross correlations among input parameters

    International Nuclear Information System (INIS)

    Clifton, P.M.

    1984-12-01

    The deep basalt formations beneath the Hanford Site are being investigated for the Department of Energy (DOE) to assess their suitability as a host medium for a high level nuclear waste repository. Predicted performance of the proposed repository is an important part of the investigation. One of the performance measures being used to gauge the suitability of the host medium is pre-waste-emplacement groundwater travel times to the accessible environment. Many deterministic analyses of groundwater travel times have been completed by Rockwell and other independent organizations. Recently, Rockwell has completed a preliminary stochastic analysis of groundwater travel times. This document presents analyses that show the sensitivity of the results from the previous stochastic travel time study to: (1) scale of representation of model parameters, (2) size of the model domain, (3) correlation range of log-transmissivity, and (4) cross-correlation between transmissivity and effective thickness. 40 refs., 29 figs., 6 tabs

  19. Output-only cyclo-stationary linear-parameter time-varying stochastic subspace identification method for rotating machinery and spinning structures

    Science.gov (United States)

    Velazquez, Antonio; Swartz, R. Andrew

    2015-02-01

    Economical maintenance and operation are critical issues for rotating machinery and spinning structures containing blade elements, especially large slender dynamic beams (e.g., wind turbines). Structural health monitoring systems represent promising instruments to assure reliability and good performance from the dynamics of the mechanical systems. However, such devices have not been completely perfected for spinning structures. These sensing technologies are typically informed by both mechanistic models coupled with data-driven identification techniques in the time and/or frequency domain. Frequency response functions are popular but are difficult to realize autonomously for structures of higher order, especially when overlapping frequency content is present. Instead, time-domain techniques have shown to possess powerful advantages from a practical point of view (i.e. low-order computational effort suitable for real-time or embedded algorithms) and also are more suitable to differentiate closely-related modes. Customarily, time-varying effects are often neglected or dismissed to simplify this analysis, but such cannot be the case for sinusoidally loaded structures containing spinning multi-bodies. A more complex scenario is constituted when dealing with both periodic mechanisms responsible for the vibration shaft of the rotor-blade system and the interaction of the supporting substructure. Transformations of the cyclic effects on the vibrational data can be applied to isolate inertial quantities that are different from rotation-generated forces that are typically non-stationary in nature. After applying these transformations, structural identification can be carried out by stationary techniques via data-correlated eigensystem realizations. In this paper, an exploration of a periodic stationary or cyclo-stationary subspace identification technique is presented here for spinning multi-blade systems by means of a modified Eigensystem Realization Algorithm (ERA) via

  20. Multifractal detrended cross-correlation analysis on gold, crude oil and foreign exchange rate time series

    Science.gov (United States)

    Pal, Mayukha; Madhusudana Rao, P.; Manimaran, P.

    2014-12-01

    We apply the recently developed multifractal detrended cross-correlation analysis method to investigate the cross-correlation behavior and fractal nature between two non-stationary time series. We analyze the daily return price of gold, West Texas Intermediate and Brent crude oil, foreign exchange rate data, over a period of 18 years. The cross correlation has been measured from the Hurst scaling exponents and the singularity spectrum quantitatively. From the results, the existence of multifractal cross-correlation between all of these time series is found. We also found that the cross correlation between gold and oil prices possess uncorrelated behavior and the remaining bivariate time series possess persistent behavior. It was observed for five bivariate series that the cross-correlation exponents are less than the calculated average generalized Hurst exponents (GHE) for q0 and for one bivariate series the cross-correlation exponent is greater than GHE for all q values.

  1. Temporal and spectral manipulations of correlated photons using a time-lens

    OpenAIRE

    Mittal, Sunil; Orre, Venkata Vikram; Restelli, Alessandro; Salem, Reza; Goldschmidt, Elizabeth A.; Hafezi, Mohammad

    2017-01-01

    A common challenge in quantum information processing with photons is the limited ability to manipulate and measure correlated states. An example is the inability to measure picosecond scale temporal correlations of a multi-photon state, given state-of-the-art detectors have a temporal resolution of about 100 ps. Here, we demonstrate temporal magnification of time-bin entangled two-photon states using a time-lens, and measure their temporal correlation function which is otherwise not accessibl...

  2. Multi-time, multi-scale correlation functions in turbulence and in turbulent models

    NARCIS (Netherlands)

    Biferale, L.; Boffetta, G.; Celani, A.; Toschi, F.

    1999-01-01

    A multifractal-like representation for multi-time, multi-scale velocity correlation in turbulence and dynamical turbulent models is proposed. The importance of subleading contributions to time correlations is highlighted. The fulfillment of the dynamical constraints due to the equations of motion is

  3. An evaluation of the optimum timing for planting short rotation coppice

    Energy Technology Data Exchange (ETDEWEB)

    Turnbull, D.J.; Jefferies, R.; Parfitt, R.

    2004-07-01

    This report summarises the results of a project to determine the optimum timing for planting, evaluate problems due to late planting in the spring, and to study the planting of willows at different times during the autumn. Details are given of the site installation, previous research on the effect of planting date and storage, and assessment of the establishment and biomass productivity and the viability of cuttings in long-term storage. Charts illustrating biomass productivity are presented, and long-term storage of willow cuttings for autumn planting is discussed.

  4. Wavelet based correlation coefficient of time series of Saudi Meteorological Data

    International Nuclear Information System (INIS)

    Rehman, S.; Siddiqi, A.H.

    2009-01-01

    In this paper, wavelet concepts are used to study a correlation between pairs of time series of meteorological parameters such as pressure, temperature, rainfall, relative humidity and wind speed. The study utilized the daily average values of meteorological parameters of nine meteorological stations of Saudi Arabia located at different strategic locations. The data used in this study cover a period of 16 years between 1990 and 2005. Besides obtaining wavelet spectra, we also computed the wavelet correlation coefficients between two same parameters from two different locations and show that strong correlation or strong anti-correlation depends on scale. The cross-correlation coefficients of meteorological parameters between two stations were also calculated using statistical function. For coastal to costal pair of stations, pressure time series was found to be strongly correlated. In general, the temperature data were found to be strongly correlated for all pairs of stations and the rainfall data the least.

  5. The correlation between urinary 5-hydroxyindoleacetic acid and sperm quality in infertile men and rotating shift workers

    OpenAIRE

    Ortiz, ?gueda; Espino, Javier; Bejarano, Ignacio; Lozano, Graciela M; Monllor, Fabi?n; Garc?a, Juan F; Pariente, Jos? A; Rodr?guez, Ana B

    2010-01-01

    Abstract Background Serotonin is a neurotransmitter that modulates a wide range of neuroendocrine functions. However, excessive circulating serotonin levels may induce harmful effects in the male reproductive system. The objective of this study was to evaluate whether the levels of urinary 5-hydroxyindoleacetic acid (5-HIIA), a major serotonin metabolite, correlate with different classical seminal parameters. Methods Human ejaculates were obtained from 40 men attending infertility counselling...

  6. Spatially heterogeneous dynamics investigated via a time-dependent four-point density correlation function

    DEFF Research Database (Denmark)

    Lacevic, N.; Starr, F. W.; Schrøder, Thomas

    2003-01-01

    correlation function g4(r,t) and corresponding "structure factor" S4(q,t) which measure the spatial correlations between the local liquid density at two points in space, each at two different times, and so are sensitive to dynamical heterogeneity. We study g4(r,t) and S4(q,t) via molecular dynamics......Relaxation in supercooled liquids above their glass transition and below the onset temperature of "slow" dynamics involves the correlated motion of neighboring particles. This correlated motion results in the appearance of spatially heterogeneous dynamics or "dynamical heterogeneity." Traditional...... two-point time-dependent density correlation functions, while providing information about the transient "caging" of particles on cooling, are unable to provide sufficiently detailed information about correlated motion and dynamical heterogeneity. Here, we study a four-point, time-dependent density...

  7. Instability of the long head of the biceps tendon in patients with rotator cuff tear: evaluation on magnetic resonance arthrography of the shoulder with arthroscopic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yusuhn; Lee, Joon Woo; Ahn, Joong Mo; Lee, Eugene; Kang, Heung Sik [Seoul National University Bundang Hospital, Department of Radiology, Seongnam-si, Gyeonggi-do (Korea, Republic of)

    2017-10-15

    To evaluate the diagnostic value of MR arthrography (MRA) in diagnosing instability of the LHBT in patients with rotator cuff tendon tear. The MR arthrograms of 101 patients were retrospectively reviewed and correlated with arthroscopic findings as the standard reference. Images were evaluated for (1) the integrity of the LHBT, (2) the position of the LHBT (subluxation/dislocation on axial images, inferior displacement on oblique sagittal image) and (3) the integrity of the biceps pulley (SGHL, supraspinatus and subscapularis tendon adjacent to the rotator interval). The integrity of the LHBT was correctly classified in 74.3% (75/101) and 66.3% (67/101) by readers 1 and 2, respectively. The diagnosis of LHBT instability could be made on axial images with a sensitivity of 82.6% and 73.9% and specificity of 69.9% and 87.7%, whereas the displacement sign on sagittal images had a sensitivity of 73.9% and 78.3% and a specificity of 64.4% and 61.6%, respectively. Assessing the integrity of the SGHL had a sensitivity of 60.9 and 93.3% and a specificity of 70.4 and 75.0%, respectively. By combining the different image findings, the accuracy in assessing LHBT instability was 80.9 and 90.5% with a sensitivity of 60.9 and 86.7% and specificity of 83.1 and 91.8%, respectively. Individual image findings may have a limited role in diagnosing LHBT instability in patients with rotator cuff tendon tear. The accuracy of MRA may be improved by assessing the integrity of the biceps pulley structures along with the position of the LHBT on both axial and sagittal images. (orig.)

  8. Numerical study of time domain analogy applied to noise prediction from rotating blades

    Science.gov (United States)

    Fedala, D.; Kouidri, S.; Rey, R.

    2009-04-01

    Aeroacoustic formulations in time domain are frequently used to model the aerodynamic sound of airfoils, the time data being more accessible. The formulation 1A developed by Farassat, an integral solution of the Ffowcs Williams and Hawkings equation, holds great interest because of its ability to handle surfaces in arbitrary motion. The aim of this work is to study the numerical sensitivity of this model to specified parameters used in the calculation. The numerical algorithms, spatial and time discretizations, and approximations used for far-field acoustic simulation are presented. An approach of quantifying of the numerical errors resulting from implementation of formulation 1A is carried out based on Isom's and Tam's test cases. A helicopter blade airfoil, as defined by Farassat to investigate Isom's case, is used in this work. According to Isom, the acoustic response of a dipole source with a constant aerodynamic load, ρ0c02, is equal to the thickness noise contribution. Discrepancies are observed when the two contributions are computed numerically. In this work, variations of these errors, which depend on the temporal resolution, Mach number, source-observer distance, and interpolation algorithm type, are investigated. The results show that the spline interpolating algorithm gives the minimum error. The analysis is then extended to Tam's test case. Tam's test case has the advantage of providing an analytical solution for the first harmonic of the noise produced by a specific force distribution.

  9. Fano-Agarwal couplings and non-rotating wave approximation in single-photon timed Dicke subradiance

    Science.gov (United States)

    Mirza, Imran M.; Begzjav, Tuguldur

    2016-04-01

    Recently a new class of single-photon timed Dicke (TD) subradiant states has been introduced with possible applications in single-photon-based quantum information storage and on demand ultrafast retrieval (Scully M. O., Phys. Rev. Lett., 115 (2015) 243602). However, the influence of any kind of virtual processes on the decay of these new kind of subradiant states has been left as an open question. In the present paper, we focus on this problem in detail. In particular, we investigate how pure Fano-Agarwal couplings and other virtual processes arising from non-rotating wave approximation impact the decay of otherwise sub- and superradiant states. In addition to the overall virtual couplings among all TD states, we also focus on the dominant role played by the couplings between specific TD states.

  10. A Robust Pre-Filter and Power Loading Design for Time Reversal UWB Systems over Time-Correlated MIMO Channels

    Directory of Open Access Journals (Sweden)

    Sajjad Alizadeh

    2014-04-01

    Full Text Available Conventional Time Reversal (TR technique suffers from performance degradation in time varying Multiple-Input Multiple-Output Ultra-Wideband (MIMO-UWB systems due to outdating Channel State Information (CSI over time progressions. That is, the outdated CSI degrades the TR performance significantly in time varying channels. The correlation property of time correlated channels can improve the TR performance against other traditional TR designs. Based on this property, at first, we propose a robust TR-MIMO-UWB system design for a time-varying channel in which the CSI is updated only at the beginning of each block of data where the CSI is assumed to be known. As the channel varies over time, pre-processor blindly pre-equalizes the channel during the next symbol time by using the correlation property. Then, a novel recursive power allocation strategy is derived over time-correlated time-varying TR-MIMO-UWB channels. We show that the proposed power loading technique, considerably improves the BER performance of TR-MIMO-UWB system in imperfect CSI with robust pre-filter. The proposed algorithms lead to a cost-efficient CSI updating procedure for the TR optimization. Simulation results are provided to confirm the new design performance against traditional method.

  11. Exact time-dependent exchange-correlation potentials for strong-field electron dynamics

    International Nuclear Information System (INIS)

    Lein, Manfred; Kuemmel, Stephan

    2005-01-01

    By solving the time-dependent Schroedinger equation and inverting the time-dependent Kohn-Sham scheme we obtain the exact time-dependent exchange-correlation potential of density-functional theory for the strong-field dynamics of a correlated system. We demonstrate that essential features of the exact exchange-correlation potential can be related to derivative discontinuities in stationary density-functional theory. Incorporating the discontinuity in a time-dependent density-functional calculation greatly improves the description of the ionization process

  12. Correlations in Many-Body systems from two-time Greens functions

    International Nuclear Information System (INIS)

    Morawetz, K.; Kohler, H.S.

    2000-01-01

    The Kadanoff-Baym (KB) equations are solved numerically for infinite nuclear matter. In particular we calculate correlation energies and correlation times. Approximating the Green's functions in the KB collision kernel by the free Green's functions the Levinson equation is obtained. This approximation is valid for weak interactions and/or low densities. It relates to the extended quasi-particle approximation for the spectral function. The Levinson correlation energy reduces for large times to a second order Born approximation for the energy. Comparing the Levinson, Born and KB calculations allows for an estimate of higher order spectral corrections to the correlations. (authors)

  13. Correcting orbital drift signal in the time series of AVHRR derived convective cloud fraction using rotated empirical orthogonal function

    Directory of Open Access Journals (Sweden)

    A. Devasthale

    2012-02-01

    Full Text Available The Advanced Very High Resolution Radiometer (AVHRR instruments onboard the series of National Oceanic and Atmospheric Administration (NOAA satellites offer the longest available meteorological data records from space. These satellites have drifted in orbit resulting in shifts in the local time sampling during the life span of the sensors onboard. Depending upon the amplitude of the diurnal cycle of the geophysical parameters derived, orbital drift may cause spurious trends in their time series. We investigate tropical deep convective clouds, which show pronounced diurnal cycle amplitude, to estimate an upper bound of the impact of orbital drift on their time series. We carry out a rotated empirical orthogonal function analysis (REOF and show that the REOFs are useful in delineating orbital drift signal and, more importantly, in subtracting this signal in the time series of convective cloud amount. These results will help facilitate the derivation of homogenized data series of cloud amount from NOAA satellite sensors and ultimately analyzing trends from them. However, we suggest detailed comparison of various methods and rigorous testing thereof applying final orbital drift corrections.

  14. Field-measured drag area is a key correlate of level cycling time trial performance

    Directory of Open Access Journals (Sweden)

    James E. Peterman

    2015-08-01

    Full Text Available Drag area (Ad is a primary factor determining aerodynamic resistance during level cycling and is therefore a key determinant of level time trial performance. However, Ad has traditionally been difficult to measure. Our purpose was to determine the value of adding field-measured Ad as a correlate of level cycling time trial performance. In the field, 19 male cyclists performed a level (22.1 km time trial. Separately, field-determined Ad and rolling resistance were calculated for subjects along with projected frontal area assessed directly (AP and indirectly (Est AP. Also, a graded exercise test was performed to determine $\\dot {V}{O}_{2}$V̇O2 peak, lactate threshold (LT, and economy. $\\dot {V}{O}_{2}$V̇O2 peak ($\\mathrm{l}~\\min ^{-1}$lmin−1 and power at LT were significantly correlated to power measured during the time trial (r = 0.83 and 0.69, respectively but were not significantly correlated to performance time (r = − 0.42 and −0.45. The correlation with performance time improved significantly (p < 0.05 when these variables were normalized to Ad. Of note, Ad alone was better correlated to performance time (r = 0.85, p < 0.001 than any combination of non-normalized physiological measure. The best correlate with performance time was field-measured power output during the time trial normalized to Ad (r = − 0.92. AP only accounted for 54% of the variability in Ad. Accordingly, the correlation to performance time was significantly lower using power normalized to AP (r = − 0.75 or Est AP (r = − 0.71. In conclusion, unless normalized to Ad, level time trial performance in the field was not highly correlated to common laboratory measures. Furthermore, our field-measured Ad is easy to determine and was the single best predictor of level time trial performance.

  15. Local normalization: Uncovering correlations in non-stationary financial time series

    Science.gov (United States)

    Schäfer, Rudi; Guhr, Thomas

    2010-09-01

    The measurement of correlations between financial time series is of vital importance for risk management. In this paper we address an estimation error that stems from the non-stationarity of the time series. We put forward a method to rid the time series of local trends and variable volatility, while preserving cross-correlations. We test this method in a Monte Carlo simulation, and apply it to empirical data for the S&P 500 stocks.

  16. Functional correlates of the position of the axis of rotation of the mandible during chewing in non-human primates.

    Science.gov (United States)

    Iriarte-Diaz, Jose; Terhune, Claire E; Taylor, Andrea B; Ross, Callum F

    2017-10-01

    The location of the axis of rotation (AoR) of the mandible was quantified using the helical axis (HA) in eight individuals from three species of non-human primates: Papio anubis, Cebus apella, and Macaca mulatta. These data were used to test three hypotheses regarding the functional significance of anteroposterior condylar translation - an AoR located inferior to the temporomandibular joint (TMJ) - during chewing: minimizing impingement of the gonial region on cervical soft tissue structures during jaw opening; avoiding stretching of the inferior alveolar neurovascular bundle (IANB); and increasing jaw-elevator muscle torques. The results reveal that the HA is located near the occlusal plane in Papio and Cebus, but closer to the condyle in Macaca; is located anteroinferior to the TMJ during both opening and closing in Papio, as well as during opening in Macaca and Cebus; and varies in its location during closing in Macaca and Cebus. The impingement hypothesis is not supported by interspecific variation in HA location: species with larger gonial angles like Cebus do not have more inferiorly located HAs than species with more obtuse mandibular angles like Papio. However, intraspecific variation provides some support for the impingement hypothesis. The HA seldom passes near or through the lingula, falsifying the hypothesis that its location is determined by the sphenomandibular ligament, and the magnitudes of strain associated with a HA at the TMJ would not be large enough to cause problematic stretching of the IANB. HA location does affect muscle moment arms about the TMJ, with implications for the torque generation capability of the jaw-elevator muscles. In Cebus, a HA farther away from the TMJ is associated with larger jaw-elevator muscle moment arms about the joint than if it were at the TMJ. The effects of HA location on muscle strain and muscle moment arms are largest at large gapes and smallest at low gapes, suggesting that if HA location is of functional

  17. Muon spin rotation studies of magnetic order and strong magnetic correlations in magnetic and superconducting systems based on the high Tc copper oxide structures

    International Nuclear Information System (INIS)

    Rudnick, J.J.; Filipkowski, M.E.; Tan, Z.; Chamberland, B.; Niedermayer, C.; Weidinger, A.; Golnik, A.; Simon, R.; Rauer, M.; Recknagel, E.; Gluckler, H.; Baines, C.

    1990-01-01

    In this paper the authors review results of a series of muon spin rotation (μSR) studies extending down to milli Kelvin temperatures in order to explore the existence of magnetic correlations below T C in the La 2-x Sr x CuO 4 system. Evidence is presented for the existence of local magnetic fields thought to originate from Cu electronic moments in both superconducting La 2-x Sr x CuO 4 and in superconducting oxygen deficient YBa 2 Cu 3 O 6.6 . μSR results are also presented for oxygen deficient and superconducting GdBa 2 Cu 3 O 6+x samples. Some discussion of the relevance of these results to recent proposals for pairing mechanisms is presented

  18. Phase synchronization based minimum spanning trees for analysis of financial time series with nonlinear correlations

    Science.gov (United States)

    Radhakrishnan, Srinivasan; Duvvuru, Arjun; Sultornsanee, Sivarit; Kamarthi, Sagar

    2016-02-01

    The cross correlation coefficient has been widely applied in financial time series analysis, in specific, for understanding chaotic behaviour in terms of stock price and index movements during crisis periods. To better understand time series correlation dynamics, the cross correlation matrices are represented as networks, in which a node stands for an individual time series and a link indicates cross correlation between a pair of nodes. These networks are converted into simpler trees using different schemes. In this context, Minimum Spanning Trees (MST) are the most favoured tree structures because of their ability to preserve all the nodes and thereby retain essential information imbued in the network. Although cross correlations underlying MSTs capture essential information, they do not faithfully capture dynamic behaviour embedded in the time series data of financial systems because cross correlation is a reliable measure only if the relationship between the time series is linear. To address the issue, this work investigates a new measure called phase synchronization (PS) for establishing correlations among different time series which relate to one another, linearly or nonlinearly. In this approach the strength of a link between a pair of time series (nodes) is determined by the level of phase synchronization between them. We compare the performance of phase synchronization based MST with cross correlation based MST along selected network measures across temporal frame that includes economically good and crisis periods. We observe agreement in the directionality of the results across these two methods. They show similar trends, upward or downward, when comparing selected network measures. Though both the methods give similar trends, the phase synchronization based MST is a more reliable representation of the dynamic behaviour of financial systems than the cross correlation based MST because of the former's ability to quantify nonlinear relationships among time

  19. An interdimensional correlation framework for real-time estimation of six degree of freedom target motion using a single x-ray imager during radiotherapy

    Science.gov (United States)

    Nguyen, D. T.; Bertholet, J.; Kim, J.-H.; O'Brien, R.; Booth, J. T.; Poulsen, P. R.; Keall, P. J.

    2018-01-01

    Increasing evidence suggests that intrafraction tumour motion monitoring needs to include both 3D translations and 3D rotations. Presently, methods to estimate the rotation motion require the 3D translation of the target to be known first. However, ideally, translation and rotation should be estimated concurrently. We present the first method to directly estimate six-degree-of-freedom (6DoF) motion from the target’s projection on a single rotating x-ray imager in real-time. This novel method is based on the linear correlations between the superior-inferior translations and the motion in the other five degrees-of-freedom. The accuracy of the method was evaluated in silico with 81 liver tumour motion traces from 19 patients with three implanted markers. The ground-truth motion was estimated using the current gold standard method where each marker’s 3D position was first estimated using a Gaussian probability method, and the 6DoF motion was then estimated from the 3D positions using an iterative method. The 3D position of each marker was projected onto a gantry-mounted imager with an imaging rate of 11 Hz. After an initial 110° gantry rotation (200 images), a correlation model between the superior-inferior translations and the five other DoFs was built using a least square method. The correlation model was then updated after each subsequent frame to estimate 6DoF motion in real-time. The proposed algorithm had an accuracy (±precision) of  -0.03  ±  0.32 mm, -0.01  ±  0.13 mm and 0.03  ±  0.52 mm for translations in the left-right (LR), superior-inferior (SI) and anterior-posterior (AP) directions respectively; and, 0.07  ±  1.18°, 0.07  ±  1.00° and 0.06  ±  1.32° for rotations around the LR, SI and AP axes respectively on the dataset. The first method to directly estimate real-time 6DoF target motion from segmented marker positions on a 2D imager was devised. The algorithm was evaluated using 81

  20. General relativistic radiative transfer code in rotating black hole space-time: ARTIST

    Science.gov (United States)

    Takahashi, Rohta; Umemura, Masayuki

    2017-02-01

    We present a general relativistic radiative transfer code, ARTIST (Authentic Radiative Transfer In Space-Time), that is a perfectly causal scheme to pursue the propagation of radiation with absorption and scattering around a Kerr black hole. The code explicitly solves the invariant radiation intensity along null geodesics in the Kerr-Schild coordinates, and therefore properly includes light bending, Doppler boosting, frame dragging, and gravitational redshifts. The notable aspect of ARTIST is that it conserves the radiative energy with high accuracy, and is not subject to the numerical diffusion, since the transfer is solved on long characteristics along null geodesics. We first solve the wavefront propagation around a Kerr black hole that was originally explored by Hanni. This demonstrates repeated wavefront collisions, light bending, and causal propagation of radiation with the speed of light. We show that the decay rate of the total energy of wavefronts near a black hole is determined solely by the black hole spin in late phases, in agreement with analytic expectations. As a result, the ARTIST turns out to correctly solve the general relativistic radiation fields until late phases as t ˜ 90 M. We also explore the effects of absorption and scattering, and apply this code for a photon wall problem and an orbiting hotspot problem. All the simulations in this study are performed in the equatorial plane around a Kerr black hole. The ARTIST is the first step to realize the general relativistic radiation hydrodynamics.

  1. Fault Diagnosis of Rotating Machinery Based on Multisensor Information Fusion Using SVM and Time-Domain Features

    Directory of Open Access Journals (Sweden)

    Ling-li Jiang

    2014-01-01

    Full Text Available Multisensor information fusion, when applied to fault diagnosis, the time-space scope, and the quantity of information are expanded compared to what could be acquired by a single sensor, so the diagnostic object can be described more comprehensively. This paper presents a methodology of fault diagnosis in rotating machinery using multisensor information fusion that all the features are calculated using vibration data in time domain to constitute fusional vector and the support vector machine (SVM is used for classification. The effectiveness of the presented methodology is tested by three case studies: diagnostic of faulty gear, rolling bearing, and identification of rotor crack. For each case study, the sensibilities of the features are analyzed. The results indicate that the peak factor is the most sensitive feature in the twelve time-domain features for identifying gear defect, and the mean, amplitude square, root mean square, root amplitude, and standard deviation are all sensitive for identifying gear, rolling bearing, and rotor crack defect comparatively.

  2. A KST framework for correlation network construction from time series signals

    Science.gov (United States)

    Qi, Jin-Peng; Gu, Quan; Zhu, Ying; Zhang, Ping

    2018-04-01

    A KST (Kolmogorov-Smirnov test and T statistic) method is used for construction of a correlation network based on the fluctuation of each time series within the multivariate time signals. In this method, each time series is divided equally into multiple segments, and the maximal data fluctuation in each segment is calculated by a KST change detection procedure. Connections between each time series are derived from the data fluctuation matrix, and are used for construction of the fluctuation correlation network (FCN). The method was tested with synthetic simulations and the result was compared with those from using KS or T only for detection of data fluctuation. The novelty of this study is that the correlation analyses was based on the data fluctuation in each segment of each time series rather than on the original time signals, which would be more meaningful for many real world applications and for analysis of large-scale time signals where prior knowledge is uncertain.

  3. The time-oriented boundary states and the Lorentzian-spinfoam correlation functions

    International Nuclear Information System (INIS)

    Bianchi, Eugenio; Ding You

    2012-01-01

    A time-oriented semiclassical boundary state is introduced to calculate the correlation function in the Lorentzian Engle-Pereira-Rovelli-Livine spinfoam model. The resulting semiclassical correlation function is shown to match with the one in Regge calculus in a proper limit.

  4. Stationary echo canceling in velocity estimation by time-domain cross-correlation

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    1993-01-01

    The application of stationary echo canceling to ultrasonic estimation of blood velocities using time-domain cross-correlation is investigated. Expressions are derived that show the influence from the echo canceler on the signals that enter the cross-correlation estimator. It is demonstrated...

  5. Detrended partial cross-correlation analysis of two nonstationary time series influenced by common external forces

    Science.gov (United States)

    Qian, Xi-Yuan; Liu, Ya-Min; Jiang, Zhi-Qiang; Podobnik, Boris; Zhou, Wei-Xing; Stanley, H. Eugene

    2015-06-01

    When common factors strongly influence two power-law cross-correlated time series recorded in complex natural or social systems, using detrended cross-correlation analysis (DCCA) without considering these common factors will bias the results. We use detrended partial cross-correlation analysis (DPXA) to uncover the intrinsic power-law cross correlations between two simultaneously recorded time series in the presence of nonstationarity after removing the effects of other time series acting as common forces. The DPXA method is a generalization of the detrended cross-correlation analysis that takes into account partial correlation analysis. We demonstrate the method by using bivariate fractional Brownian motions contaminated with a fractional Brownian motion. We find that the DPXA is able to recover the analytical cross Hurst indices, and thus the multiscale DPXA coefficients are a viable alternative to the conventional cross-correlation coefficient. We demonstrate the advantage of the DPXA coefficients over the DCCA coefficients by analyzing contaminated bivariate fractional Brownian motions. We calculate the DPXA coefficients and use them to extract the intrinsic cross correlation between crude oil and gold futures by taking into consideration the impact of the U.S. dollar index. We develop the multifractal DPXA (MF-DPXA) method in order to generalize the DPXA method and investigate multifractal time series. We analyze multifractal binomial measures masked with strong white noises and find that the MF-DPXA method quantifies the hidden multifractal nature while the multifractal DCCA method fails.

  6. Generalized Correlation Coefficient for Non-Parametric Analysis of Microarray Time-Course Data.

    Science.gov (United States)

    Tan, Qihua; Thomassen, Mads; Burton, Mark; Mose, Kristian Fredløv; Andersen, Klaus Ejner; Hjelmborg, Jacob; Kruse, Torben

    2017-06-06

    Modeling complex time-course patterns is a challenging issue in microarray study due to complex gene expression patterns in response to the time-course experiment. We introduce the generalized correlation coefficient and propose a combinatory approach for detecting, testing and clustering the heterogeneous time-course gene expression patterns. Application of the method identified nonlinear time-course patterns in high agreement with parametric analysis. We conclude that the non-parametric nature in the generalized correlation analysis could be an useful and efficient tool for analyzing microarray time-course data and for exploring the complex relationships in the omics data for studying their association with disease and health.

  7. Correlation Between Contrast Time-Density Time on Digital Subtraction Angiography and Flow: An in Vitro Study.

    Science.gov (United States)

    Brunozzi, Denise; Shakur, Sophia F; Ismail, Rahim; Linninger, Andreas; Hsu, Chih-Yang; Charbel, Fady T; Alaraj, Ali

    2018-02-01

    Digital subtraction angiography (DSA) provides an excellent anatomic characterization of cerebral vasculature, but hemodynamic assessment is often qualitative and subjective. Various clinical algorithms have been produced to semiquantify flow from the data obtained from DSA, but few have tested them against reliable flow values. An arched flow model was created and injected with contrast material. Seventeen injections were acquired in anterior-posterior and lateral DSA projections, and 4 injections were acquired in oblique projection. Image intensity change over the angiogram cycle of each DSA run was analyzed through a custom MATLAB code. Time-density plots obtained were divided into 3 components (time-density times, TDTs): TDT 10%-100% (time needed for contrast material to change image intensity from 10% to 100%), TDT 100%-10% (time needed for contrast material to change image intensity from 100% to 10%), and TDT 25%-25% (time needed for contrast material to change from 25% image intensity to 25%). Time-density index (TDI) was defined as model cross-sectional area to TDT ratio, and it was measured against different flow rates. TDI 10%-100% , TDI 100%-10% , and TDI 25%-25% all correlated significantly with flow (P < 0.001). TDI 10%-100% , TDI 100%-10% , and TDI 25%-25% showed, respectively, a correlation coefficient of 0.91, 0.91, and 0.97 in the anterior-posterior DSA projections (P < 0.001). In the lateral DSA projection, TDI 100%-10% showed a weaker correlation (r = 0.57; P = 0.03). Also in the oblique DSA projection, TDIs correlated significantly with flow. TDI on DSA correlates significantly with flow. Although in vitro studies might overlook conditions that occur in patients, this method appears to correlate with the flow and could offer a semiquantitative method to evaluate the cerebral blood flow. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Autocorrelation and cross-correlation in time series of homicide and attempted homicide

    Science.gov (United States)

    Machado Filho, A.; da Silva, M. F.; Zebende, G. F.

    2014-04-01

    We propose in this paper to establish the relationship between homicides and attempted homicides by a non-stationary time-series analysis. This analysis will be carried out by Detrended Fluctuation Analysis (DFA), Detrended Cross-Correlation Analysis (DCCA), and DCCA cross-correlation coefficient, ρ(n). Through this analysis we can identify a positive cross-correlation between homicides and attempted homicides. At the same time, looked at from the point of view of autocorrelation (DFA), this analysis can be more informative depending on time scale. For short scale (days), we cannot identify auto-correlations, on the scale of weeks DFA presents anti-persistent behavior, and for long time scales (n>90 days) DFA presents a persistent behavior. Finally, the application of this new type of statistical analysis proved to be efficient and, in this sense, this paper can contribute to a more accurate descriptive statistics of crime.

  9. The unsteady flow of a nanofluid in the stagnation point region of a time-dependent rotating sphere

    Directory of Open Access Journals (Sweden)

    Malvandi Amir

    2015-01-01

    Full Text Available This paper deals with the unsteady boundary layer flow and heat transfer of nanofluid over a time-dependent rotating sphere where the free stream velocity varies continuously with time. The boundary layer equations were normalized via similarity variables and solved numerically. Best accuracy of the results has been obtained for regular fluid with previous studies. The nanofluid is treated as a two-component mixture (base fluid+nanoparticles that incorporates the effects of Brownian diffusion and thermophoresis simultaneously as the two most important mechanisms of slip velocity in laminar flows. Our outcomes indicated that as A and λ increase, surface shear stresses, heat transfer and concentration rates, climb up. Also, Increasing the thermophoresis Nt is found to decrease in the both values of heat transfer and concentration rates. This decrease supresses for higher thermophoresis number. In addition, it was observed that unlike the heat transfer rate, a rise in Brownian motion Nb, leads to an increase in concentration rate.

  10. Time-to-digital converter for a time-correlation analyzer

    International Nuclear Information System (INIS)

    Kumpf, S.

    1979-01-01

    An electronic circuit operating as a time-to-digital converter is described. It receives pulses from eight n-detectors on eight input channels which are converted into the first half of a 16-bit word. The work called 'label' is indicating the channel on which an event has arrived. Contemporarily a crystal controlled four stage 4-bit binary counter gives the time when the event arrives expressed in the form of a second 16-bit work called 'time'. These two words are fed via a FIFO-buffer and a DMA-control to a very fast minicomputer Miproc 16 from Plessey-Micro-Systems with a cycle time of 250 ns. The circuit is built in TTL-technique on two double Europa-format cards and is built into the card bay of the Miproc 16 and acts as a peripheral device

  11. Student Perceptions of Sectional CT/MRI Use in Teaching Veterinary Anatomy and the Correlation with Visual Spatial Ability: A Student Survey and Mental Rotations Test.

    Science.gov (United States)

    Delisser, Peter J; Carwardine, Darren

    2017-11-29

    Diagnostic imaging technology is becoming more advanced and widely available to veterinary patients with the growing popularity of veterinary-specific computed tomography (CT) and magnetic resonance imaging (MRI). Veterinary students must, therefore, be familiar with these technologies and understand the importance of sound anatomic knowledge for interpretation of the resultant images. Anatomy teaching relies heavily on visual perception of structures and their function. In addition, visual spatial ability (VSA) positively correlates with anatomy test scores. We sought to assess the impact of including more diagnostic imaging, particularly CT/MRI, in the teaching of veterinary anatomy on the students' perceived level of usefulness and ease of understanding content. Finally, we investigated survey answers' relationship to the students' inherent baseline VSA, measured by a standard Mental Rotations Test. Students viewed diagnostic imaging as a useful inclusion that provided clear links to clinical relevance, thus improving the students' perceived benefits in its use. Use of CT and MRI images was not viewed as more beneficial, more relevant, or more useful than the use of radiographs. Furthermore, students felt that the usefulness of CT/MRI inclusion was mitigated by the lack of prior formal instruction on the basics of CT/MRI image generation and interpretation. To be of significantly greater use, addition of learning resources labeling relevant anatomy in tomographical images would improve utility of this novel teaching resource. The present study failed to find any correlation between student perceptions of diagnostic imaging in anatomy teaching and their VSA.

  12. Real-Time Corrected Traffic Correlation Model for Traffic Flow Forecasting

    Directory of Open Access Journals (Sweden)

    Hua-pu Lu

    2015-01-01

    Full Text Available This paper focuses on the problems of short-term traffic flow forecasting. The main goal is to put forward traffic correlation model and real-time correction algorithm for traffic flow forecasting. Traffic correlation model is established based on the temporal-spatial-historical correlation characteristic of traffic big data. In order to simplify the traffic correlation model, this paper presents correction coefficients optimization algorithm. Considering multistate characteristic of traffic big data, a dynamic part is added to traffic correlation model. Real-time correction algorithm based on Fuzzy Neural Network is presented to overcome the nonlinear mapping problems. A case study based on a real-world road network in Beijing, China, is implemented to test the efficiency and applicability of the proposed modeling methods.

  13. Impacts of Earth rotation parameters on GNSS ultra-rapid orbit prediction: Derivation and real-time correction

    Science.gov (United States)

    Wang, Qianxin; Hu, Chao; Xu, Tianhe; Chang, Guobin; Hernández Moraleda, Alberto

    2017-12-01

    Analysis centers (ACs) for global navigation satellite systems (GNSSs) cannot accurately obtain real-time Earth rotation parameters (ERPs). Thus, the prediction of ultra-rapid orbits in the international terrestrial reference system (ITRS) has to utilize the predicted ERPs issued by the International Earth Rotation and Reference Systems Service (IERS) or the International GNSS Service (IGS). In this study, the accuracy of ERPs predicted by IERS and IGS is analyzed. The error of the ERPs predicted for one day can reach 0.15 mas and 0.053 ms in polar motion and UT1-UTC direction, respectively. Then, the impact of ERP errors on ultra-rapid orbit prediction by GNSS is studied. The methods for orbit integration and frame transformation in orbit prediction with introduced ERP errors dominate the accuracy of the predicted orbit. Experimental results show that the transformation from the geocentric celestial references system (GCRS) to ITRS exerts the strongest effect on the accuracy of the predicted ultra-rapid orbit. To obtain the most accurate predicted ultra-rapid orbit, a corresponding real-time orbit correction method is developed. First, orbits without ERP-related errors are predicted on the basis of ITRS observed part of ultra-rapid orbit for use as reference. Then, the corresponding predicted orbit is transformed from GCRS to ITRS to adjust for the predicted ERPs. Finally, the corrected ERPs with error slopes are re-introduced to correct the predicted orbit in ITRS. To validate the proposed method, three experimental schemes are designed: function extrapolation, simulation experiments, and experiments with predicted ultra-rapid orbits and international GNSS Monitoring and Assessment System (iGMAS) products. Experimental results show that using the proposed correction method with IERS products considerably improved the accuracy of ultra-rapid orbit prediction (except the geosynchronous BeiDou orbits). The accuracy of orbit prediction is enhanced by at least 50

  14. On the zero temperature limit of the Kubo-transformed quantum time correlation function

    Science.gov (United States)

    Hernández de la Peña, Lisandro

    2014-04-01

    The zero temperature limit of several quantum time correlation functions is analysed. It is shown that while the canonical quantum time correlation function retains the full dynamical information as temperature approaches zero, the Kubo-transformed and the thermally symmetrised quantum time correlation functions lose all dynamical information at this limit. This is shown to be a consequence of the projection onto the ground state, via the limiting process of the quantities ? and ?, either together as a product, or separately. Although these findings would seem to suggest that finite-temperature methods commonly used to estimate Kubo correlation functions would be incapable of retaining any ground state dynamics, we propose a route for recovering in principle all dynamical information at the ground state. It is first shown that the usual frequency space relation between canonical and Kubo correlation functions also holds for microcanonical time correlation functions. Since the Kubo-transformed microcanonical correlation function can be obtained from the usual finite-temperature function by including a projection onto the corresponding microcanonical ensemble, finite-temperature methods, properly modified to incorporate such a constraint, can be used to capture full quantum dynamics at any arbitrary energy state, including the ground state. This approach is illustrated with the application of centroid dynamics to the ground state dynamics of the harmonic oscillator.

  15. Approximate number and approximate time discrimination each correlate with school math abilities in young children.

    Science.gov (United States)

    Odic, Darko; Lisboa, Juan Valle; Eisinger, Robert; Olivera, Magdalena Gonzalez; Maiche, Alejandro; Halberda, Justin

    2016-01-01

    What is the relationship between our intuitive sense of number (e.g., when estimating how many marbles are in a jar), and our intuitive sense of other quantities, including time (e.g., when estimating how long it has been since we last ate breakfast)? Recent work in cognitive, developmental, comparative psychology, and computational neuroscience has suggested that our representations of approximate number, time, and spatial extent are fundamentally linked and constitute a "generalized magnitude system". But, the shared behavioral and neural signatures between number, time, and space may alternatively be due to similar encoding and decision-making processes, rather than due to shared domain-general representations. In this study, we investigate the relationship between approximate number and time in a large sample of 6-8 year-old children in Uruguay by examining how individual differences in the precision of number and time estimation correlate with school mathematics performance. Over four testing days, each child completed an approximate number discrimination task, an approximate time discrimination task, a digit span task, and a large battery of symbolic math tests. We replicate previous reports showing that symbolic math abilities correlate with approximate number precision and extend those findings by showing that math abilities also correlate with approximate time precision. But, contrary to approximate number and time sharing common representations, we find that each of these dimensions uniquely correlates with formal math: approximate number correlates more strongly with formal math compared to time and continues to correlate with math even when precision in time and individual differences in working memory are controlled for. These results suggest that there are important differences in the mental representations of approximate number and approximate time and further clarify the relationship between quantity representations and mathematics. Copyright

  16. Dual channel detection of ultra low concentration of bacteria in real time by scanning fluorescence correlation spectroscopy

    Science.gov (United States)

    Altamore, Ilaria; Lanzano, Luca; Gratton, Enrico

    2013-06-01

    We describe a novel method to detect very low concentrations of bacteria in water. Our device consists of a portable horizontal geometry small confocal microscope with large pinhole and a holder for cylindrical cuvettes containing the sample. Two motors provide fast rotational and slow vertical motion of the cuvette so the device looks like a simplified flow cytometer without flow. To achieve high sensitivity, the design has two detection channels. Bacteria are stained by two different nucleic acid dyes and excited with two different lasers. Data are analyzed with a correlation filter based on particle passage pattern recognition. The passage of a particle through the illumination volume is compared with a Gaussian pattern in both channels. The width of the Gaussian correlates with the time of passage of the particle so one particle is counted when the algorithm finds a match with a Gaussian in both channels. The concentration of particles in the sample is deduced from the total number of coincident hits and the total volume scanned. This portable setup provides higher sensitivity, low-cost advantage, and it can have a wide use ranging from clinical applications to pollution monitors and water and air quality control.

  17. Dual channel detection of ultra low concentration of bacteria in real time by scanning fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Altamore, Ilaria; Lanzano, Luca; Gratton, Enrico

    2013-01-01

    We describe a novel method to detect very low concentrations of bacteria in water. Our device consists of a portable horizontal geometry small confocal microscope with large pinhole and a holder for cylindrical cuvettes containing the sample. Two motors provide fast rotational and slow vertical motion of the cuvette so the device looks like a simplified flow cytometer without flow. To achieve high sensitivity, the design has two detection channels. Bacteria are stained by two different nucleic acid dyes and excited with two different lasers. Data are analyzed with a correlation filter based on particle passage pattern recognition. The passage of a particle through the illumination volume is compared with a Gaussian pattern in both channels. The width of the Gaussian correlates with the time of passage of the particle so one particle is counted when the algorithm finds a match with a Gaussian in both channels. The concentration of particles in the sample is deduced from the total number of coincident hits and the total volume scanned. This portable setup provides higher sensitivity, low-cost advantage, and it can have a wide use ranging from clinical applications to pollution monitors and water and air quality control. (paper)

  18. Decay of Complex-Time Determinantal and Pfaffian Correlation Functionals in Lattices

    Science.gov (United States)

    Aza, N. J. B.; Bru, J.-B.; de Siqueira Pedra, W.

    2018-06-01

    We supplement the determinantal and Pfaffian bounds of Sims and Warzel (Commun Math Phys 347:903-931, 2016) for many-body localization of quasi-free fermions, by considering the high dimensional case and complex-time correlations. Our proof uses the analyticity of correlation functions via the Hadamard three-line theorem. We show that the dynamical localization for the one-particle system yields the dynamical localization for the many-point fermionic correlation functions, with respect to the Hausdorff distance in the determinantal case. In Sims and Warzel (2016), a stronger notion of decay for many-particle configurations was used but only at dimension one and for real times. Considering determinantal and Pfaffian correlation functionals for complex times is important in the study of weakly interacting fermions.

  19. Decay of Complex-Time Determinantal and Pfaffian Correlation Functionals in Lattices

    Science.gov (United States)

    Aza, N. J. B.; Bru, J.-B.; de Siqueira Pedra, W.

    2018-04-01

    We supplement the determinantal and Pfaffian bounds of Sims and Warzel (Commun Math Phys 347:903-931, 2016) for many-body localization of quasi-free fermions, by considering the high dimensional case and complex-time correlations. Our proof uses the analyticity of correlation functions via the Hadamard three-line theorem. We show that the dynamical localization for the one-particle system yields the dynamical localization for the many-point fermionic correlation functions, with respect to the Hausdorff distance in the determinantal case. In Sims and Warzel (2016), a stronger notion of decay for many-particle configurations was used but only at dimension one and for real times. Considering determinantal and Pfaffian correlation functionals for complex times is important in the study of weakly interacting fermions.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  1. Paleomagnetism of Jurassic and Cretaceous rocks in central Patagonia: a key to constrain the timing of rotations during the breakup of southwestern Gondwana?

    Science.gov (United States)

    Geuna, Silvana E.; Somoza, Rubén; Vizán, Haroldo; Figari, Eduardo G.; Rinaldi, Carlos A.

    2000-08-01

    A paleomagnetic study in Jurassic and Cretaceous rocks from the Cañadón Asfalto basin, central Patagonia, indicates the occurrence of about 25-30° clockwise rotation in Upper Jurassic-lowermost Cretaceous rocks, whereas the overlying mid-Cretaceous rocks do not show evidence of rotation. This constrains the tectonic rotation to be related to a major regional unconformity in Patagonia, which in turn seems to be close in time with the early opening of the South Atlantic Ocean. The sense and probably the timing of this rotation are similar to those of other paleomagnetically detected rotations in different areas of southwestern Gondwana, suggesting a possible relationship between these and major tectonic processes related with fragmentation of the supercontinent. On the other hand, the mid-Cretaceous rocks in the region yield a paleopole located at Lat. 87° South, Long. 159° East, A95=3.8°. This pole position is consistent with coeval high-quality paleopoles of other plates when transferred to South American coordinates, implying it is an accurate determination of the Aptian (circa 116 Ma) geomagnetic field in South America.

  2. Integrated rotating-compensator polarimeter for real-time measurements and analysis of organometallic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Flock, K.; Kim, S.-J.; Asar, M.; Kim, I.K.; Aspnes, D.E

    2004-05-01

    We describe a single-beam rotating-compensator rotating-sample spectroscopic polarimeter (RCSSP) integrated with an organometallic chemical vapor deposition (OMCVD) reactor for in-situ diagnostics and control of epitaxial growth, and report representative results. The rotating compensator generates Fourier coefficients that provide information about layer thicknesses and compositions, while sample rotation provides information about optical anisotropy and therefore surface chemistry. We illustrate capabilities with various examples, including the simultaneous determination of <{epsilon}> and {alpha}{sub 10} during exposure of (001)GaAs to TMG, the heteroepitaxial growth of GaP on GaAs, and the growth of (001)GaSb with TMG and TMSb. Using a recently developed approach for quantitatively determining thickness and dielectric function of depositing layers, we find the presence of metallic Ga on TMG-exposed (001)GaAs. The (001)GaSb data show that Sb deposition is self-limiting, in contrast to expectations.

  3. Time Correlations of Lightning Flash Sequences in Thunderstorms Revealed by Fractal Analysis

    Science.gov (United States)

    Gou, Xueqiang; Chen, Mingli; Zhang, Guangshu

    2018-01-01

    By using the data of lightning detection and ranging system at the Kennedy Space Center, the temporal fractal and correlation of interevent time series of lightning flash sequences in thunderstorms have been investigated with Allan factor (AF), Fano factor (FF), and detrended fluctuation analysis (DFA) methods. AF, FF, and DFA methods are powerful tools to detect the time-scaling structures and correlations in point processes. Totally 40 thunderstorms with distinguishing features of a single-cell storm and apparent increase and decrease in the total flash rate were selected for the analysis. It is found that the time-scaling exponents for AF (αAF) and FF (αFF) analyses are 1.62 and 0.95 in average, respectively, indicating a strong time correlation of the lightning flash sequences. DFA analysis shows that there is a crossover phenomenon—a crossover timescale (τc) ranging from 54 to 195 s with an average of 114 s. The occurrence of a lightning flash in a thunderstorm behaves randomly at timescales τc but shows strong time correlation at scales >τc. Physically, these may imply that the establishment of an extensive strong electric field necessary for the occurrence of a lightning flash needs a timescale >τc, which behaves strongly time correlated. But the initiation of a lightning flash within a well-established extensive strong electric field may involve the heterogeneities of the electric field at a timescale τc, which behave randomly.

  4. Parent-Child Shared Time from Middle Childhood to Late Adolescence: Developmental Course and Adjustment Correlates

    Science.gov (United States)

    Lam, Chun Bun; McHale, Susan M.; Crouter, Ann C.

    2012-01-01

    The development and adjustment correlates of parent-child social (parent, child, and others present) and dyadic time (only parent and child present) from age 8 to 18 were examined. Mothers, fathers, and firstborns and secondborns from 188 White families participated in both home and nightly phone interviews. Social time declined across…

  5. The Cherenkov correlated timing detector: beam test results from quartz and acrylic bars

    International Nuclear Information System (INIS)

    Kichimi, H.; Sugaya, Y.; Yamaguchi, H.; Yoshimura, Y.; Kanda, S.; Olsen, S.; Ueno, K.; Varner, G.; Bergfeld, T.; Bialek, J.; Lorenc, J.; Palmer, M.; Rudnick, G.; Selen, M.; Auran, T.; Boyer, V.; Honscheid, K.; Tamura, N.; Yoshimura, K.; Lu, C.; Marlow, D.; Mindas, C.; Prebys, E.; Asai, M.; Kimura, A.; Hayashi, S.

    1996-01-01

    Several prototypes of a Cherenkov correlated timing (CCT) detector have been tested at the KEK-PS test beam line. We describe the results for Cherenkov light yields and timing characteristics from quartz and acrylic bar prototypes. A Cherenkov angle resolution is found to be 15 mrad at a propagation distance of 100 cm with a 2 cm thick quartz bar prototype. (orig.)

  6. Monitoring of unfractionated heparin with rotational thrombelastometry using the prothrombinase-induced clotting time reagent (PiCT®).

    Science.gov (United States)

    Schaden, E; Jilch, S; Hacker, S; Schober, A; Kozek-Langenecker, S

    2012-12-24

    To achieve sufficient and safe anticoagulation with unfractionated heparin (UFH) a close and reliable drug monitoring is necessary. In general, the activated partial thromboplastin time (APTT) is used for this purpose. In acute phase response, however, the APTT test procedure might be unreliable e.g. with false low results in the presence of elevated factor VIII. In this so called heparin resistance, measurement of anti-Xa activity is recommended over APTT to avoid potentially harmful dose escalation. A combination of anti-Xa measurement and global hemostatic testing with ROTEM® employing the anti-Xa sensitive PiCT® reagent showed high correlation with enoxaparin levels. This test modification could also be suitable for monitoring UFH. Aim of the study was to evaluate the correlation between PiCT®-ROTEM® and levels of UFH. In this in-vitro study blood samples from healthy volunteers were spiked with UFH and subjected to different ROTEM® tests. There was a linear correlation between UFH level and clotting time (CT) in the PiCT®-ROTEM® test with an excellent correlation coefficient of 0.92. Additional endpoints showed similar results (PiCT®-ROTEM® MaxVel r = -0.85 and PiCT®-ROTEM® t_MaxVel r = 0.88). As a point-of-care applicable tool ROTEM® is immediately at hand. If further clinical studies confirm sensitivity in heparin resistance, PiCT®-ROTEM® could permit rapid UFH dose adjustments especially required in critical illness with acute phase response. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Short-range correlations in an extended time-dependent mean-field theory

    International Nuclear Information System (INIS)

    Madler, P.

    1982-01-01

    A generalization is performed of the time-dependent mean-field theory by an explicit inclusion of strong short-range correlations on a level of microscopic reversibility relating them to realistic nucleon-nucleon forces. Invoking a least action principle for correlated trial wave functions, equations of motion for the correlation functions and the single-particle model wave function are derived in lowest order of the FAHT cluster expansion. Higher order effects as well as long-range correlations are consider only to the extent to which they contribute to the mean field via a readjusted phenomenological effective two-body interaction. The corresponding correlated stationary problem is investigated and appropriate initial conditions to describe a heavy ion reaction are proposed. The singleparticle density matrix is evaluated

  8. T2 relaxation time analysis in patients with multiple sclerosis: correlation with magnetization transfer ratio

    International Nuclear Information System (INIS)

    Papanikolaou, Nickolas; Papadaki, Eufrosini; Karampekios, Spyros; Maris, Thomas; Prassopoulos, Panos; Gourtsoyiannis, Nicholas; Spilioti, Martha

    2004-01-01

    The aim of the current study was to perform T2 relaxation time measurements in multiple sclerosis (MS) patients and correlate them with magnetization transfer ratio (MTR) measurements, in order to investigate in more detail the various histopathological changes that occur in lesions and normal-appearing white matter (NAWM). A total number of 291 measurements of MTR and T2 relaxation times were performed in 13 MS patients and 10 age-matched healthy volunteers. Measurements concerned MS plaques (105), NAWM (80), and ''dirty'' white matter (DWM; 30), evenly divided between the MS patients, and normal white matter (NWM; 76) in the healthy volunteers. Biexponential T2 relaxation-time analysis was performed, and also possible linearity between MTR and mean T2 relaxation times was evaluated using linear regression analysis in all subgroups. Biexponential relaxation was more pronounced in ''black-hole'' lesions (16.6%) and homogeneous enhancing plaques (10%), whereas DWM, NAWM, and mildly hypointense lesions presented biexponential behavior with a lower frequency(6.6, 5, and 3.1%, respectively). Non-enhancing isointense lesions and normal white matter did not reveal any biexponentional behavior. Linear regression analysis between monoexponential T2 relaxation time and MTR measurements demonstrated excellent correlation for DWM(r=-0.78, p<0.0001), very good correlation for black-hole lesions(r=-0.71, p=0.002), good correlation for isointense lesions(r=-0.60, p=0.005), moderate correlation for mildly hypointense lesions(r=-0.34, p=0.007), and non-significant correlation for homogeneous enhancing plaques, NAWM, and NWM. Biexponential T2 relaxation-time behavior is seen in only very few lesions (mainly on plaques with high degree of demyelination and axonal loss). A strong correlation between MTR and monoexponential T2 values was found in regions where either inflammation or demyelination predominates; however, when both pathological conditions coexist, this linear

  9. Time-dependent importance sampling in semiclassical initial value representation calculations for time correlation functions. II. A simplified implementation.

    Science.gov (United States)

    Tao, Guohua; Miller, William H

    2012-09-28

    An efficient time-dependent (TD) Monte Carlo (MC) importance sampling method has recently been developed [G. Tao and W. H. Miller, J. Chem. Phys. 135, 024104 (2011)] for the evaluation of time correlation functions using the semiclassical (SC) initial value representation (IVR) methodology. In this TD-SC-IVR method, the MC sampling uses information from both time-evolved phase points as well as their initial values, and only the "important" trajectories are sampled frequently. Even though the TD-SC-IVR was shown in some benchmark examples to be much more efficient than the traditional time-independent sampling method (which uses only initial conditions), the calculation of the SC prefactor-which is computationally expensive, especially for large systems-is still required for accepted trajectories. In the present work, we present an approximate implementation of the TD-SC-IVR method that is completely prefactor-free; it gives the time correlation function as a classical-like magnitude function multiplied by a phase function. Application of this approach to flux-flux correlation functions (which yield reaction rate constants) for the benchmark H + H(2) system shows very good agreement with exact quantum results. Limitations of the approximate approach are also discussed.

  10. Timing the tides: genetic control of diurnal and lunar emergence times is correlated in the marine midge Clunio marinus.

    Science.gov (United States)

    Kaiser, Tobias S; Neumann, Dietrich; Heckel, David G

    2011-05-20

    The intertidal zone of seacoasts, being affected by the superimposed tidal, diurnal and lunar cycles, is temporally the most complex environment on earth. Many marine organisms exhibit lunar rhythms in reproductive behaviour and some show experimental evidence of endogenous control by a circalunar clock, the molecular and genetic basis of which is unexplored. We examined the genetic control of lunar and diurnal rhythmicity in the marine midge Clunio marinus (Chironomidae, Diptera), a species for which the correct timing of adult emergence is critical in natural populations. We crossed two strains of Clunio marinus that differ in the timing of the diurnal and lunar rhythms of emergence. The phenotype distribution of the segregating backcross progeny indicates polygenic control of the lunar emergence rhythm. Diurnal timing of emergence is also under genetic control, and is influenced by two unlinked genes with major effects. Furthermore, the lunar and diurnal timing of emergence is correlated in the backcross generation. We show that both the lunar emergence time and its correlation to the diurnal emergence time are adaptive for the species in its natural environment. The correlation implies that the unlinked genes affecting lunar timing and the two unlinked genes affecting diurnal timing could be the same, providing an unexpectedly close interaction of the two clocks. Alternatively, the genes could be genetically linked in a two-by-two fashion, suggesting that evolution has shaped the genetic architecture to stabilize adaptive combinations of lunar and diurnal emergence times by tightening linkage. Our results, the first on genetic control of lunar rhythms, offer a new perspective to explore their molecular clockwork.

  11. Long-time correlation for the chaotic orbit in the two-wave Hamiltonian

    International Nuclear Information System (INIS)

    Hatori, Tadatsugu; Irie, Haruyuki.

    1987-03-01

    The time correlation function of velocity is found to decay with the power law for the orbit governed by a Hamiltonian, H = v 2 /2-M cos x - P cos[k(x - t)]. The renormalization group technique can predict the power of decay for the correlation function defined by the ensemble average. The power spectrum becomes the 1/f-type for a special case. (author)

  12. IBM PC based real time photon correlator [Paper No.:D2

    International Nuclear Information System (INIS)

    Kumaravadivelu, C.; Nageswaran, A.; Weling, S. A.

    1993-01-01

    The design aspects and development of IBM PC based real time photon correlator is presented. This system computes 64 auto-correlation functions in real time. Sample data is 4-bit wide. Correlation functions are computed in hard wired logic using discrete components. A combination of parallel and pipelined architecture is adopted to compute the correlation in realtime. A high speed controller generates the required control signals for the computing hardware and also provides handshake signals to IBM PC to access the computed results. IBM PC bus is extended and interfaced to correlation computing hardware. IBM PC collects the experimental parameters through user friendly menu and initiates the correlation hardware and continues to collect the correlation build ups and displays them on the screen. Extensive test and maintenance features are incorporated into the system. This system is developed for Material Science Division in Indira Gandhi Centre for Atomic Research (IGCAR) to study static and dynamic properties of macro molecules and colloidal particles in dispersion using light scattering technique. It can also be used to study the flow characteristics of sodium in nuclear reactors. It can be used in dynamic neutron scattering experiments. (author). 3 figs., 2 tabs

  13. Rotating flow

    CERN Document Server

    Childs, Peter R N

    2010-01-01

    Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows-which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circul...

  14. Rotational seismology

    Science.gov (United States)

    Lee, William H K.

    2016-01-01

    Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

  15. Vorticity vector-potential method based on time-dependent curvilinear coordinates for two-dimensional rotating flows in closed configurations

    Science.gov (United States)

    Fu, Yuan; Zhang, Da-peng; Xie, Xi-lin

    2018-04-01

    In this study, a vorticity vector-potential method for two-dimensional viscous incompressible rotating driven flows is developed in the time-dependent curvilinear coordinates. The method is applicable in both inertial and non-inertial frames of reference with the advantage of a fixed and regular calculation domain. The numerical method is applied to triangle and curved triangle configurations in constant and varying rotational angular velocity cases respectively. The evolutions of flow field are studied. The geostrophic effect, unsteady effect and curvature effect on the evolutions are discussed.

  16. Non-Gaussian lineshapes and dynamics of time-resolved linear and nonlinear (correlation) spectra.

    Science.gov (United States)

    Dinpajooh, Mohammadhasan; Matyushov, Dmitry V

    2014-07-17

    Signatures of nonlinear and non-Gaussian dynamics in time-resolved linear and nonlinear (correlation) 2D spectra are analyzed in a model considering a linear plus quadratic dependence of the spectroscopic transition frequency on a Gaussian nuclear coordinate of the thermal bath (quadratic coupling). This new model is contrasted to the commonly assumed linear dependence of the transition frequency on the medium nuclear coordinates (linear coupling). The linear coupling model predicts equality between the Stokes shift and equilibrium correlation functions of the transition frequency and time-independent spectral width. Both predictions are often violated, and we are asking here the question of whether a nonlinear solvent response and/or non-Gaussian dynamics are required to explain these observations. We find that correlation functions of spectroscopic observables calculated in the quadratic coupling model depend on the chromophore's electronic state and the spectral width gains time dependence, all in violation of the predictions of the linear coupling models. Lineshape functions of 2D spectra are derived assuming Ornstein-Uhlenbeck dynamics of the bath nuclear modes. The model predicts asymmetry of 2D correlation plots and bending of the center line. The latter is often used to extract two-point correlation functions from 2D spectra. The dynamics of the transition frequency are non-Gaussian. However, the effect of non-Gaussian dynamics is limited to the third-order (skewness) time correlation function, without affecting the time correlation functions of higher order. The theory is tested against molecular dynamics simulations of a model polar-polarizable chromophore dissolved in a force field water.

  17. TIME-SERIES PHOTOMETRY OF STARS IN AND AROUND THE LAGOON NEBULA. I. ROTATION PERIODS OF 290 LOW-MASS PRE-MAIN-SEQUENCE STARS IN NGC 6530

    International Nuclear Information System (INIS)

    Henderson, Calen B.; Stassun, Keivan G.

    2012-01-01

    We have conducted a long-term, wide-field, high-cadence photometric monitoring survey of ∼50,000 stars in the Lagoon Nebula H II region. This first paper presents rotation periods for 290 low-mass stars in NGC 6530, the young cluster illuminating the nebula, and for which we assemble a catalog of infrared and spectroscopic disk indicators, estimated masses and ages, and X-ray luminosities. The distribution of rotation periods we measure is broadly uniform for 0.5 days X /L bol ≈ –3.3). However, we find a significant positive correlation between L X /L bol and corotation radius, suggesting that the observed X-ray luminosities are regulated by centrifugal stripping of the stellar coronae. The period-mass relationship in NGC 6530 is broadly similar to that of the Orion Nebula Cluster (ONC), but the slope of the relationship among the slowest rotators differs from that in the ONC and other young clusters. We show that the slope of the period-mass relationship for the slowest rotators can be used as a proxy for the age of a young cluster, and we argue that NGC 6530 may be slightly younger than the ONC, making it a particularly important touchstone for models of angular momentum evolution in young, low-mass stars.

  18. Generalized Correlation Coefficient for Non-Parametric Analysis of Microarray Time-Course Data

    DEFF Research Database (Denmark)

    Tan, Qihua; Thomassen, Mads; Burton, Mark

    2017-01-01

    the heterogeneous time-course gene expression patterns. Application of the method identified nonlinear time-course patterns in high agreement with parametric analysis. We conclude that the non-parametric nature in the generalized correlation analysis could be an useful and efficient tool for analyzing microarray...... time-course data and for exploring the complex relationships in the omics data for studying their association with disease and health....

  19. Wide-field time-correlated single photon counting (TCSPC) microscopy with time resolution below the frame exposure time

    Energy Technology Data Exchange (ETDEWEB)

    Hirvonen, Liisa M. [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Petrášek, Zdeněk [Max Planck Institute of Biochemistry, Department of Cellular and Molecular Biophysics, Am Klopferspitz 18, D-82152 Martinsried (Germany); Suhling, Klaus, E-mail: klaus.suhling@kcl.ac.uk [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom)

    2015-07-01

    Fast frame rate CMOS cameras in combination with photon counting intensifiers can be used for fluorescence imaging with single photon sensitivity at kHz frame rates. We show here how the phosphor decay of the image intensifier can be exploited for accurate timing of photon arrival well below the camera exposure time. This is achieved by taking ratios of the intensity of the photon events in two subsequent frames, and effectively allows wide-field TCSPC. This technique was used for measuring decays of ruthenium compound Ru(dpp) with lifetimes as low as 1 μs with 18.5 μs frame exposure time, including in living HeLa cells, using around 0.1 μW excitation power. We speculate that by using an image intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could well be possible.

  20. Social correlates of leisure-time sedentary behaviours in Canadian adults.

    Science.gov (United States)

    Huffman, S; Szafron, M

    2017-03-01

    Research on the correlates of sedentary behaviour among adults is needed to design health interventions to modify this behaviour. This study explored the associations of social correlates with leisure-time sedentary behaviour of Canadian adults, and whether these associations differ between different types of sedentary behaviour. A sample of 12,021 Canadian adults was drawn from the 2012 Canadian Community Health Survey, and analyzed using binary logistic regression to model the relationships that marital status, the presence of children in the household, and social support have with overall time spent sitting, using a computer, playing video games, watching television, and reading during leisure time. Covariates included gender, age, education, income, employment status, perceived health, physical activity level, body mass index (BMI), and province or territory of residence. Extensive computer time was primarily negatively related to being in a common law relationship, and primarily positively related to being single/never married. Being single/never married was positively associated with extensive sitting time in men only. Having children under 12 in the household was protective against extensive video game and reading times. Increasing social support was negatively associated with extensive computer time in men and women, while among men increasing social support was positively associated with extensive sitting time. Computer, video game, television, and reading time have unique correlates among Canadian adults. Marital status, the presence of children in the household, and social support should be considered in future analyses of sedentary activities in adults.

  1. Social correlates of leisure-time sedentary behaviours in Canadian adults

    Directory of Open Access Journals (Sweden)

    S. Huffman

    2017-03-01

    Full Text Available Research on the correlates of sedentary behaviour among adults is needed to design health interventions to modify this behaviour. This study explored the associations of social correlates with leisure-time sedentary behaviour of Canadian adults, and whether these associations differ between different types of sedentary behaviour. A sample of 12,021 Canadian adults was drawn from the 2012 Canadian Community Health Survey, and analyzed using binary logistic regression to model the relationships that marital status, the presence of children in the household, and social support have with overall time spent sitting, using a computer, playing video games, watching television, and reading during leisure time. Covariates included gender, age, education, income, employment status, perceived health, physical activity level, body mass index (BMI, and province or territory of residence. Extensive computer time was primarily negatively related to being in a common law relationship, and primarily positively related to being single/never married. Being single/never married was positively associated with extensive sitting time in men only. Having children under 12 in the household was protective against extensive video game and reading times. Increasing social support was negatively associated with extensive computer time in men and women, while among men increasing social support was positively associated with extensive sitting time. Computer, video game, television, and reading time have unique correlates among Canadian adults. Marital status, the presence of children in the household, and social support should be considered in future analyses of sedentary activities in adults.

  2. Correlation between detrended fluctuation analysis and the Lempel-Ziv complexity in nonlinear time series analysis

    International Nuclear Information System (INIS)

    Tang You-Fu; Liu Shu-Lin; Jiang Rui-Hong; Liu Ying-Hui

    2013-01-01

    We study the correlation between detrended fluctuation analysis (DFA) and the Lempel-Ziv complexity (LZC) in nonlinear time series analysis in this paper. Typical dynamic systems including a logistic map and a Duffing model are investigated. Moreover, the influence of Gaussian random noise on both the DFA and LZC are analyzed. The results show a high correlation between the DFA and LZC, which can quantify the non-stationarity and the nonlinearity of the time series, respectively. With the enhancement of the random component, the exponent a and the normalized complexity index C show increasing trends. In addition, C is found to be more sensitive to the fluctuation in the nonlinear time series than α. Finally, the correlation between the DFA and LZC is applied to the extraction of vibration signals for a reciprocating compressor gas valve, and an effective fault diagnosis result is obtained

  3. 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.

  4. 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

  5. The EDGE-CALIFA survey: the influence of galactic rotation on the molecular depletion time across the Hubble sequence

    Science.gov (United States)

    Colombo, D.; Kalinova, V.; Utomo, D.; Rosolowsky, E.; Bolatto, A. D.; Levy, R. C.; Wong, T.; Sanchez, S. F.; Leroy, A. K.; Ostriker, E.; Blitz, L.; Vogel, S.; Mast, D.; García-Benito, R.; Husemann, B.; Dannerbauer, H.; Ellmeier, L.; Cao, Y.

    2018-04-01

    We present a kpc-scale analysis of the relationship between the molecular depletion time (τ^mol_dep) and the orbital time (τorb) across the field of 39 face-on local galaxies, selected from the EDGE-CALIFA sample. We find that, on average, 5 per cent of the available molecular gas is converted into stars per orbital time, or τ^mol_dep˜ 20 τ_orb. The resolved relation shows a scatter of ˜0.5 dex. The scatter is ascribable to galaxies of different morphologies that follow different τ^mol_dep-τorb relations which decrease in steepness from early- to late types. The morphologies appear to be linked with the star formation rate surface density, the molecular depletion time, and the orbital time, but they do not correlate with the molecular gas content of the galaxies in our sample. We speculate that in our molecular gas rich, early-type galaxies, the morphological quenching (in particular the disc stabilization via shear), rather than the absence of molecular gas, is the main factor responsible for their current inefficient star formation.

  6. Self-organized criticality, long-time correlations, and the standard transport paradigm

    International Nuclear Information System (INIS)

    Krommes, J.A.

    2000-01-01

    Some aspects of low-frequency, long-wavelength fluctuations are considered. A stochastic model is used to show that power-law time correlations need not arise from self-organized criticality. A formula for the frequency spectrum of uncorrelated, overlapping avalanches is shown to be a special case of the spectral balance equation of renormalized statistical turbulence theory. It is argued that there need be no contradiction between the presence of long-time correlations and the existence of local transport coefficients

  7. Heterogeneous dynamics of ionic liquids: A four-point time correlation function approach

    Science.gov (United States)

    Liu, Jiannan; Willcox, Jon A. L.; Kim, Hyung J.

    2018-05-01

    Many ionic liquids show behavior similar to that of glassy systems, e.g., large and long-lasted deviations from Gaussian dynamics and clustering of "mobile" and "immobile" groups of ions. Herein a time-dependent four-point density correlation function—typically used to characterize glassy systems—is implemented for the ionic liquids, choline acetate, and 1-butyl-3-methylimidazolium acetate. Dynamic correlation beyond the first ionic solvation shell on the time scale of nanoseconds is found in the ionic liquids, revealing the cooperative nature of ion motions. The traditional solvent, acetonitrile, on the other hand, shows a much shorter length-scale that decays after a few picoseconds.

  8. Time-of-flight camera via a single-pixel correlation image sensor

    Science.gov (United States)

    Mao, Tianyi; Chen, Qian; He, Weiji; Dai, Huidong; Ye, Ling; Gu, Guohua

    2018-04-01

    A time-of-flight imager based on single-pixel correlation image sensors is proposed for noise-free depth map acquisition in presence of ambient light. Digital micro-mirror device and time-modulated IR-laser provide spatial and temporal illumination on the unknown object. Compressed sensing and ‘four bucket principle’ method are combined to reconstruct the depth map from a sequence of measurements at a low sampling rate. Second-order correlation transform is also introduced to reduce the noise from the detector itself and direct ambient light. Computer simulations are presented to validate the computational models and improvement of reconstructions.

  9. Fluorescence decay time imaging using an imaging photon detector with a radio frequency photon correlation system

    Science.gov (United States)

    Morgan, Christopher G.; Mitchell, A. C.; Murray, J. G.

    1990-05-01

    An imaging photon detector has been modified to incorporate fast timing electronics coupled to a custom built photon correlator interfaced to a RISC computer. Using excitation with intensity- muodulated light, fluorescence images can be readily obtained where contrast is determined by the decay time of emission, rather than by intensity. This technology is readily extended to multifrequency phase/demodulation fluorescence imaging or to differential polarised phase fluorometry. The potential use of the correlator for confocal imaging with a laser scanner is also briefly discussed.

  10. Travel Cost Inference from Sparse, Spatio-Temporally Correlated Time Series Using Markov Models

    DEFF Research Database (Denmark)

    Yang, Bin; Guo, Chenjuan; Jensen, Christian S.

    2013-01-01

    of such time series offers insight into the underlying system and enables prediction of system behavior. While the techniques presented in the paper apply more generally, we consider the case of transportation systems and aim to predict travel cost from GPS tracking data from probe vehicles. Specifically, each...... road segment has an associated travel-cost time series, which is derived from GPS data. We use spatio-temporal hidden Markov models (STHMM) to model correlations among different traffic time series. We provide algorithms that are able to learn the parameters of an STHMM while contending...... with the sparsity, spatio-temporal correlation, and heterogeneity of the time series. Using the resulting STHMM, near future travel costs in the transportation network, e.g., travel time or greenhouse gas emissions, can be inferred, enabling a variety of routing services, e.g., eco-routing. Empirical studies...

  11. Analysis of neutron multiplicity measurements with allowance for dead-time losses between time-correlated detections

    International Nuclear Information System (INIS)

    Vincent, C.H.

    1992-01-01

    An exact solution is found for dead-time losses between detections occurring within a gate interval, with constant dead time and with allowance for time correlation between detections from the same spontaneous initial event. This is used to obtain a close approximation to the losses with a multi-channel detection system, with allowance for dead times briding the gate opening. This is applied, inversely, to calculate the true detection multiplicity rates from the distribution of the recorded counts within that interval. A suggestion is made for a circuit change to give a major reduction in dead-time effects. The unavoidable statistical errors that would remain are calculated. Their minimization and the limits of such minimization are discussed. (orig.)

  12. Asteroid rotation rates

    International Nuclear Information System (INIS)

    Binzel, R.P.; Farinella, P.

    1989-01-01

    Within the last decade the data base of asteroid rotation parameters (rotation rates and lightcurve amplitudes) has become sufficiently large to identify some definite rends and properties which can help us to interpret asteroid collisional evolution. Many significant correlations are found between rotation parameters and diameter, with distinct changes occurring near 125 km. The size range, which is also the diameter above which self-gravity may become important, perhaps represents a division between surviving primordial asteroids and collisional fragments. A Maxwellian is able to fit the observed rotation rate distributions of asteroids with D>125 km, implying that their rotation rates may be determined by collisional evolution. Asteroids with D<125 km show an excess of slow rotators and their non-Maxwellian distributions suggests that their rotation rates are more strongly influenced by other processes, such as the distribution resulting from their formation in catastrophic disruption events. Other correlations observed in the data set include different mean rotation rates for C, S and M type asteroids implying that their surface spectra are indicative of bulk properties

  13. Television Time among Brazilian Adolescents: Correlated Factors are Different between Boys and Girls

    Directory of Open Access Journals (Sweden)

    Diego Augusto Santos Silva

    2014-01-01

    Full Text Available Objective. The aim of this study was to identify the prevalence of excess television time and verify correlated factors in adolescent males and females. Methods. This cross-sectional study included 2,105 adolescents aged from 13 to 18 years from the city of Aracaju, Northeastern Brazil. Television time was self-reported, corresponding to the time spent watching television in a typical week. Several correlates were examined including age, skin color, socioeconomic status, parent education, physical activity level, consumption of fruits and vegetables, smoking status, alcohol use, and sports team participation. Results. The prevalence excess television time (≥2 hours/day in girls and boys was 70.9% and 66.2%, respectively. Girls with low socioeconomic status or inadequate consumption of fruits and vegetables were more likely to have excess television time. Among boys, those >16 years of age or with black skin color were more likely to have excess television time. Conclusions. Excess television time was observed in more than two-thirds of adolescents, being more evident in girls. Correlated factors differed according to sex. Efforts to reduce television time among Brazilian adolescents, and replace with more active pursuits, may yield desirable public health benefits.

  14. Television time among Brazilian adolescents: correlated factors are different between boys and girls.

    Science.gov (United States)

    Silva, Diego Augusto Santos; Tremblay, Mark Stephen; Gonçalves, Eliane Cristina de Andrade; Silva, Roberto Jerônimo dos Santos

    2014-01-01

    The aim of this study was to identify the prevalence of excess television time and verify correlated factors in adolescent males and females. This cross-sectional study included 2,105 adolescents aged from 13 to 18 years from the city of Aracaju, Northeastern Brazil. Television time was self-reported, corresponding to the time spent watching television in a typical week. Several correlates were examined including age, skin color, socioeconomic status, parent education, physical activity level, consumption of fruits and vegetables, smoking status, alcohol use, and sports team participation. The prevalence excess television time (≥ 2 hours/day) in girls and boys was 70.9% and 66.2%, respectively. Girls with low socioeconomic status or inadequate consumption of fruits and vegetables were more likely to have excess television time. Among boys, those >16 years of age or with black skin color were more likely to have excess television time. Excess television time was observed in more than two-thirds of adolescents, being more evident in girls. Correlated factors differed according to sex. Efforts to reduce television time among Brazilian adolescents, and replace with more active pursuits, may yield desirable public health benefits.

  15. Hypertrophy of the extra-articular tendon of the long head of biceps correlates with the location and size of a rotator cuff tear.

    Science.gov (United States)

    Takahashi, N; Sugaya, H; Matsuki, K; Miyauchi, H; Matsumoto, M; Tokai, M; Onishi, K; Hoshika, S; Ueda, Y

    2017-06-01

    The aim of this study was to assess hypertrophy of the extra-articular tendon of the long head of biceps (LHB) in patients with a rotator cuff tear. The study involved 638 shoulders in 334 patients (175 men, 159 women, mean age 62.6 years; 25 to 81) with unilateral symptomatic rotator cuff tears. The cross-sectional area (CSA) of the LHB tendon in the bicipital groove was measured pre-operatively in both shoulders using ultrasound. There were 154 asymptomatic rotator cuff tears in the contralateral shoulder. Comparisons were made between those with a symptomatic tear, an asymptomatic tear and those with no rotator cuff tear. In the affected shoulders, the CSAs were compared in relation to the location and size of the rotator cuff tear. The mean CSA was 21.0 mm 2 (4 to 71) in those with a symptomatic rotator cuff tear, 19.9 mm 2 (4 to 75) in those with an asymptomatic rotator cuff tear and 14.1 mm 2 (5 to 43) in those with no rotator cuff tear. The mean CSA in patients with both symptomatic and asymptomatic rotator cuff tears was significantly larger than in those with no rotator cuff tear (p cuff tear and those with an antero-superior cuff tear. Regardless of the symptoms, there was significant hypertrophy of the extra-articular LHB tendon in patients with a rotator cuff tear. The values were significantly related to the size of the tear. Cite this article: Bone Joint J 2017;99-B:806-11. ©2017 The British Editorial Society of Bone & Joint Surgery.

  16. Imaginary time density-density correlations for two-dimensional electron gases at high density

    Energy Technology Data Exchange (ETDEWEB)

    Motta, M.; Galli, D. E. [Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Moroni, S. [IOM-CNR DEMOCRITOS National Simulation Center and SISSA, Via Bonomea 265, 34136 Trieste (Italy); Vitali, E. [Department of Physics, College of William and Mary, Williamsburg, Virginia 23187-8795 (United States)

    2015-10-28

    We evaluate imaginary time density-density correlation functions for two-dimensional homogeneous electron gases of up to 42 particles in the continuum using the phaseless auxiliary field quantum Monte Carlo method. We use periodic boundary conditions and up to 300 plane waves as basis set elements. We show that such methodology, once equipped with suitable numerical stabilization techniques necessary to deal with exponentials, products, and inversions of large matrices, gives access to the calculation of imaginary time correlation functions for medium-sized systems. We discuss the numerical stabilization techniques and the computational complexity of the methodology and we present the limitations related to the size of the systems on a quantitative basis. We perform the inverse Laplace transform of the obtained density-density correlation functions, assessing the ability of the phaseless auxiliary field quantum Monte Carlo method to evaluate dynamical properties of medium-sized homogeneous fermion systems.

  17. Field transients of coherent terahertz synchrotron radiation accessed via time-resolving and correlation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pohl, A.; Hübers, H.-W. [Humboldt-Universität zu Berlin, Institute of Physics, Newtonstraße 15, 12489 Berlin (Germany); Institute of Optical Sensor Systems, German Aerospace Center (DLR), Rutherfordstrasse 29, 12489 Berlin (Germany); Semenov, A. [Institute of Optical Sensor Systems, German Aerospace Center (DLR), Rutherfordstrasse 29, 12489 Berlin (Germany); Hoehl, A.; Ulm, G. [Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin (Germany); Ries, M.; Wüstefeld, G. [Helmholz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Ilin, K.; Thoma, P.; Siegel, M. [Institute of Micro- and Nanoelectronic Systems, Karlsruhe Institute of Technology (KIT), Hertzstrasse 16, 76187 Karlsruhe (Germany)

    2016-03-21

    Decaying oscillations of the electric field in repetitive pulses of coherent synchrotron radiation in the terahertz frequency range was evaluated by means of time-resolving and correlation techniques. Comparative analysis of real-time voltage transients of the electrical response and interferograms, which were obtained with an ultrafast zero-bias Schottky diode detector and a Martin-Puplett interferometer, delivers close values of the pulse duration. Consistent results were obtained via the correlation technique with a pair of Golay Cell detectors and a pair of resonant polarisation-sensitive superconducting detectors integrated on one chip. The duration of terahertz synchrotron pulses does not closely correlate with the duration of single-cycle electric field expected for the varying size of electron bunches. We largely attribute the difference to the charge density oscillations in electron bunches and to the low-frequency spectral cut-off imposed by both the synchrotron beamline and the coupling optics of our detectors.

  18. Characterization of relaxation processes in interacting vortex matter through a time-dependent correlation length

    International Nuclear Information System (INIS)

    Pleimling, Michel; Täuber, Uwe C

    2015-01-01

    Vortex lines in type-II superconductors display complicated relaxation processes due to the intricate competition between their mutual repulsive interactions and pinning to attractive point or extended defects. We perform extensive Monte Carlo simulations for an interacting elastic line model with either point-like or columnar pinning centers. From measurements of the space- and time-dependent height-height correlation function for lateral flux line fluctuations, we extract a characteristic correlation length that we use to investigate different non-equilibrium relaxation regimes. The specific time dependence of this correlation length for different disorder configurations displays characteristic features that provide a novel diagnostic tool to distinguish between point-like pinning centers and extended columnar defects. (paper)

  19. Modes of correlated angular motion in live cells across three distinct time scales

    International Nuclear Information System (INIS)

    Harrison, Andrew W; Kenwright, David A; Woodman, Philip G; Allan, Victoria J; Waigh, Thomas A

    2013-01-01

    Particle tracking experiments with high speed digital microscopy yield the positions and trajectories of lipid droplets inside living cells. Angular correlation analysis shows that the lipid droplets have uncorrelated motion at short time scales (τ 10 ms, becomes persistent, indicating directed movement. The motion at all time scales is associated with the lipid droplets being tethered to and driven along the microtubule network. The point at which the angular correlation changes from anti-persistent to persistent motion corresponds to the cross over between sub-diffusive and super diffusive motion, as observed by mean square displacement analysis. Correct analysis of the angular correlations of the detector noise is found to be crucial in modelling the observed phenomena. (paper)

  20. Schizotypal perceptual aberrations of time: correlation between score, behavior and brain activity.

    Directory of Open Access Journals (Sweden)

    Shahar Arzy

    Full Text Available A fundamental trait of the human self is its continuum experience of space and time. Perceptual aberrations of this spatial and temporal continuity is a major characteristic of schizophrenia spectrum disturbances--including schizophrenia, schizotypal personality disorder and schizotypy. We have previously found the classical Perceptual Aberration Scale (PAS scores, related to body and space, to be positively correlated with both behavior and temporo-parietal activation in healthy participants performing a task involving self-projection in space. However, not much is known about the relationship between temporal perceptual aberration, behavior and brain activity. To this aim, we composed a temporal Perceptual Aberration Scale (tPAS similar to the traditional PAS. Testing on 170 participants suggested similar performance for PAS and tPAS. We then correlated tPAS and PAS scores to participants' performance and neural activity in a task of self-projection in time. tPAS scores correlated positively with reaction times across task conditions, as did PAS scores. Evoked potential mapping and electrical neuroimaging showed self-projection in time to recruit a network of brain regions at the left anterior temporal cortex, right temporo-parietal junction, and occipito-temporal cortex, and duration of activation in this network positively correlated with tPAS and PAS scores. These data demonstrate that schizotypal perceptual aberrations of both time and space, as reflected by tPAS and PAS scores, are positively correlated with performance and brain activation during self-projection in time in healthy individuals along the schizophrenia spectrum.

  1. Correlates of urban children's leisure-time physical activity and sedentary behaviors during school days.

    Science.gov (United States)

    Marques, Adilson; Sallis, James F; Martins, João; Diniz, José; Carreiro Da Costa, Francisco

    2014-01-01

    Understanding correlates of physical activity and sedentary behaviors may contribute to fostering active lifestyles. This study aimed to identify correlates of physical activity and sedentary behaviors in leisure-time among Portuguese urban children, during school days. A cross-sectional survey was conducted with 802 students (416 boys), aged 10-12 years. A questionnaire was used to collect data of physical activity, sedentary behaviors, psychological and behavioral variables related to physical activity and sedentary behaviors. Analyses were run separately for boys and girls. Television viewing occupied the most leisure-time of boys and girls, followed by computer usage, and video game playing. These behaviors occupied 259.7 min/day for boys and 208.6 for girls (P = 0.002). Reported moderate-to-vigorous physical activity was 23.7 min for boys and 12.8 min for girls (P time with joint physical activity time. Copyright © 2014 Wiley Periodicals, Inc.

  2. Quantifying NMR relaxation correlation and exchange in articular cartilage with time domain analysis

    Science.gov (United States)

    Mailhiot, Sarah E.; Zong, Fangrong; Maneval, James E.; June, Ronald K.; Galvosas, Petrik; Seymour, Joseph D.

    2018-02-01

    Measured nuclear magnetic resonance (NMR) transverse relaxation data in articular cartilage has been shown to be multi-exponential and correlated to the health of the tissue. The observed relaxation rates are dependent on experimental parameters such as solvent, data acquisition methods, data analysis methods, and alignment to the magnetic field. In this study, we show that diffusive exchange occurs in porcine articular cartilage and impacts the observed relaxation rates in T1-T2 correlation experiments. By using time domain analysis of T2-T2 exchange spectroscopy, the diffusive exchange time can be quantified by measurements that use a single mixing time. Measured characteristic times for exchange are commensurate with T1 in this material and so impacts the observed T1 behavior. The approach used here allows for reliable quantification of NMR relaxation behavior in cartilage in the presence of diffusive fluid exchange between two environments.

  3. Original article The effect of three-dimensional imaging of well-known objects on time and accuracy of mental rotation

    Directory of Open Access Journals (Sweden)

    Piotr Francuz

    2014-07-01

    Full Text Available Background The purpose of this study was to verify hypotheses concerning the effect of three-dimensional imaging and the canonicity of objects presented in the original position on the reaction time (RT and the accuracy (A of mental rotation task (MRT execution. The classical paradigm of MRT, developed by Shepard and Metzler (1971, was used in the experiment. Participants and procedure One hundred fifty-eight undergraduate students (88 female and 70 male, aged 18-30 years, participated in the experiment. All participants had normal vision or corrected vision, and reported no stereo blindness. The sequential version of the MRT was used in the experiment. Participants answered whether the object observed in the second position was only rotated or both rotated and mirror-reversed, in comparison to its original position. The answer (accuracy and its latency (RT were recorded. Results As predicted by the mental rotation model, both the “U”-shaped A-MRT distribution and the inverted “U”-shaped RT-MRT distribution were found, due to the angular disparity. For the RT-MRT, this effect was more pronounced when the objects were displayed stereoscopically than in a plane, and when the objects were presented in the original position from the canonical orientation rather than an unusual point of view. On the other hand, in the case of the A-MRT, an effect of the orientation of objects presented in the original position on strengthening the relationship between accuracy and angular disparity was found. Conclusions The results indicated that the interactions between the presentation of the objects in the mental rotation task (stereoscopically vs. in a plane and the orientation of the object in its original position (canonically vs. unusual are more complicated than would appear from predictions of classical theories of mental rotation. The results of this study are discussed in relation to the theories of recognition and categorization.

  4. In vivo time-gated diffuse correlation spectroscopy at quasi-null source-detector separation.

    Science.gov (United States)

    Pagliazzi, M; Sekar, S Konugolu Venkata; Di Sieno, L; Colombo, L; Durduran, T; Contini, D; Torricelli, A; Pifferi, A; Mora, A Dalla

    2018-06-01

    We demonstrate time domain diffuse correlation spectroscopy at quasi-null source-detector separation by using a fast time-gated single-photon avalanche diode without the need of time-tagging electronics. This approach allows for increased photon collection, simplified real-time instrumentation, and reduced probe dimensions. Depth discriminating, quasi-null distance measurement of blood flow in a human subject is presented. We envision the miniaturization and integration of matrices of optical sensors of increased spatial resolution and the enhancement of the contrast of local blood flow changes.

  5. Are the correlates of sport participation similar to those of screen time?

    Directory of Open Access Journals (Sweden)

    Mark S. Allen

    2015-01-01

    Conclusion: Our findings show that demographic, socioeconomic and environmental factors measured at age 4 predict sport participation and screen time at age 12, and that the correlates of childhood sport participation and childhood sedentary behavior may be more similar than previously estimated.

  6. A Concurrent Implementation of the Cascade-Correlation Algorithm, Using the Time Warp Operating System

    Science.gov (United States)

    Springer, P.

    1993-01-01

    This paper discusses the method in which the Cascade-Correlation algorithm was parallelized in such a way that it could be run using the Time Warp Operating System (TWOS). TWOS is a special purpose operating system designed to run parellel discrete event simulations with maximum efficiency on parallel or distributed computers.

  7. Physiological Correlations with Short, Medium, and Long Cycling Time-Trial Performance

    Science.gov (United States)

    Borszcz, Fernando K.; Tramontin, Artur F.; de Souza, Kristopher M.; Carminatti, Lorival J.; Costa, Vitor P.

    2018-01-01

    Purpose: Several studies have demonstrated that physiological variables predict cycling endurance performance. However, it is still unclear whether the predictors will change over different performance durations. The aim of this study was to assess the correlations between physiological variables and cycling time trials with different durations.…

  8. Volatility spillover and time-varying conditional correlation between DDGS, corn, and soybean meal markets

    NARCIS (Netherlands)

    Etienne, Xiaoli L.; Trujillo-Barrera, Andrés; Hoffman, Linwood A.

    2017-01-01

    We find distiller's dried grains with solubles (DDGS) prices to be positively correlated with both corn and soybean meal prices in the long run. However, neither corn nor soybean meal prices respond to deviations from this long-run relationship. We also identify strong time-varying dynamic

  9. Quantification of transuranic elements by time interval correlation spectroscopy of the detected neutrons

    Science.gov (United States)

    Baeten; Bruggeman; Paepen; Carchon

    2000-03-01

    The non-destructive quantification of transuranic elements in nuclear waste management or in safeguards verifications is commonly performed by passive neutron assay techniques. To minimise the number of unknown sample-dependent parameters, Neutron Multiplicity Counting (NMC) is applied. We developed a new NMC-technique, called Time Interval Correlation Spectroscopy (TICS), which is based on the measurement of Rossi-alpha time interval distributions. Compared to other NMC-techniques, TICS offers several advantages.

  10. Variability of OH rotational temperatures on time scales from hours to 15 years by kinetic temperature variations, emission layer changes, and non-LTE effects

    Science.gov (United States)

    Noll, Stefan

    2016-07-01

    Rotational temperatures derived from hydroxyl (OH) line emission are frequently used to study atmospheric temperatures at altitudes of about 87 km. While the measurement only requires intensities of a few bright lines of an OH band, the interpretation can be complicated. Ground-based temperatures are averages for the entire, typically 8 km wide emission layer. Variations in the rotational temperature are then caused by changes of the kinetic temperature and the OH emission profile. The latter can also be accompanied by differences in the layer-averaged efficiency of the thermalisation of the OH rotational level populations. Since this especially depends on the frequency of collisions with O_2, which is low at high altitudes, the non-local thermodynamic equilibrium (non-LTE) contribution to the measured temperatures can be significant and variable. In order to understand the impact of the different sources of OH rotational temperature variations from time scales of hours to a solar cycle, we have studied spectra from the astronomical echelle spectrographs X-shooter and UVES located at Cerro Paranal in Chile. While the X-shooter data spanning 3.5 years allowed us to measure temperatures for 25 OH and two O_2 bands, the UVES spectra cover no more than 10 OH bands simultaneously but a period of about 15 years. These data have been complemented by kinetic temperature and OH and O_2 emission profiles from the multi-channel radiometer SABER on the TIMED satellite. Taking the O_2 and SABER kinetic temperatures as reference and considering the different band-dependent emission profiles, we could evaluate the contribution of non-LTE effects to the measured OH rotational temperatures depending on line set, band, and time. Non-LTE contributions are significant for most bands and can exceed 10 K. The amplitudes of their average nocturnal and seasonal variation are of the order of 1 to 2 K.

  11. Variability of interconnected wind plants: correlation length and its dependence on variability time scale

    Science.gov (United States)

    St. Martin, Clara M.; Lundquist, Julie K.; Handschy, Mark A.

    2015-04-01

    The variability in wind-generated electricity complicates the integration of this electricity into the electrical grid. This challenge steepens as the percentage of renewably-generated electricity on the grid grows, but variability can be reduced by exploiting geographic diversity: correlations between wind farms decrease as the separation between wind farms increases. But how far is far enough to reduce variability? Grid management requires balancing production on various timescales, and so consideration of correlations reflective of those timescales can guide the appropriate spatial scales of geographic diversity grid integration. To answer ‘how far is far enough,’ we investigate the universal behavior of geographic diversity by exploring wind-speed correlations using three extensive datasets spanning continents, durations and time resolution. First, one year of five-minute wind power generation data from 29 wind farms span 1270 km across Southeastern Australia (Australian Energy Market Operator). Second, 45 years of hourly 10 m wind-speeds from 117 stations span 5000 km across Canada (National Climate Data Archive of Environment Canada). Finally, four years of five-minute wind-speeds from 14 meteorological towers span 350 km of the Northwestern US (Bonneville Power Administration). After removing diurnal cycles and seasonal trends from all datasets, we investigate dependence of correlation length on time scale by digitally high-pass filtering the data on 0.25-2000 h timescales and calculating correlations between sites for each high-pass filter cut-off. Correlations fall to zero with increasing station separation distance, but the characteristic correlation length varies with the high-pass filter applied: the higher the cut-off frequency, the smaller the station separation required to achieve de-correlation. Remarkable similarities between these three datasets reveal behavior that, if universal, could be particularly useful for grid management. For high

  12. Time and space-correlated plasma potential measurements in the near field of a coaxial Hall plasma discharge

    International Nuclear Information System (INIS)

    Smith, A. W.; Cappelli, M. A.

    2009-01-01

    Space- and time-correlated measurements of floating and plasma potential are made in the near field, external flow cathode region of a coaxial Hall plasma discharge using an emissive probe synchronized to quasicoherent fluctuations in discharge current. The luminous axial feature frequently observed in the near field of operating plasma accelerators is found to be concomitant with a spike in the plasma potential (and electron temperature). The structure of the plasma potential allows for multiple avenues for back-streaming ions to accelerate toward the discharge front pole and may pull some classes of ions toward the central axis. The fluctuations in plasma properties exhibit a complex structure at frequencies on the order of the so-called 'breathing mode' ionization instability often seen in these types of discharges. Most notably, the plasma potential appears to fluctuate in a helical fashion, resembling tilted drift waves rotating about the central axis. A simple analysis of these waves draws attention to the possible role that they may play in driving anomalous cross-field electron transport in the near field region.

  13. Reconstruction of 3D flow structures in a cylindrical cavity with a rotating lid using time-resolved stereo PIV

    DEFF Research Database (Denmark)

    Meyer, Knud Erik; Sørensen, Jens Nørkær; Naumov, Igor

    2009-01-01

    variations. The flow in a cylindrical cavity with a rotating lid of a height of three radii and a Reynolds number of about 3500 is used as example. The reconstruction identifies a series of flow structures including axisymmetric vortex breakdown and distinct vortex structures along the cylinder wall....

  14. A Note on Classification of Spatially Homogeneous Rotating Space-Times According to Their Teleparallel Killing Vector Fields in Teleparallel Theory of Gravitation

    International Nuclear Information System (INIS)

    Shabbir, Ghulam; Khan, Suhail; Ali, Amjad

    2011-01-01

    In this paper we classify spatially homogeneous rotating space-times according to their teleparallel Killing vector fields using direct integration technique. It turns out that the dimension of the teleparallel Killing vector fields is 5 or 10. In the case of 10 teleparallel Killing vector fields the space-time becomes Minkowski and all the torsion components are zero. Teleparallel Killing vector fields in this case are exactly the same as in general relativity. In the cases of 5 teleparallel Killing vector fields we get two more conservation laws in the teleparallel theory of gravitation. Here we also discuss some well-known examples of spatially homogeneous rotating space-times according to their teleparallel Killing vector fields. (general)

  15. Parent-Child Shared Time From Middle Childhood to Late Adolescence: Developmental Course and Adjustment Correlates

    Science.gov (United States)

    Lam, Chun Bun; McHale, Susan M.; Crouter, Ann C.

    2012-01-01

    The development and adjustment correlates of parent-child social (parent, child, and others present) and dyadic time (only parent and child present) from age 8 to 18 were examined. Mothers, fathers, and firstborns and secondborns from 188 White families participated in both home and nightly phone interviews. Social time declined across adolescence, but dyadic time with mothers and fathers peaked in early and middle adolescence, respectively. Additionally, secondborns’ social time declined more slowly than firstborns’, and gendered time use patterns were more pronounced in boys and in opposite-sex sibling dyads. Finally, youths who spent more dyadic time with their fathers, on average, had higher general self-worth, and changes in social time with fathers were positively linked to changes in social competence. PMID:22925042

  16. Parent-child shared time from middle childhood to late adolescence: developmental course and adjustment correlates.

    Science.gov (United States)

    Lam, Chun Bun; McHale, Susan M; Crouter, Ann C

    2012-11-01

    The development and adjustment correlates of parent-child social (parent, child, and others present) and dyadic time (only parent and child present) from age 8 to 18 were examined. Mothers, fathers, and firstborns and secondborns from 188 White families participated in both home and nightly phone interviews. Social time declined across adolescence, but dyadic time with mothers and fathers peaked in early and middle adolescence, respectively. In addition, secondborns' social time declined more slowly than firstborns', and gendered time use patterns were more pronounced in boys and in opposite-sex sibling dyads. Finally, youths who spent more dyadic time with their fathers, on average, had higher general self-worth, and changes in social time with fathers were positively linked to changes in social competence. © 2012 The Authors. Child Development © 2012 Society for Research in Child Development, Inc.

  17. Demographic correlates of screen time and objectively measured sedentary time and physical activity among toddlers: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Valerie Carson

    2017-02-01

    Full Text Available Abstract Background Determining the most important demographic correlates of sedentary behavior and physical activity will help identify the groups of children that are most in need of intervention. Little is known in regards to the demographic correlates of sedentary behavior and physical activity in toddlers (aged 12–35 months, where long-term behavioral patterns may initially be formed. Therefore, the objective of this study was to examine the associations between demographic correlates and specific types of sedentary behavior and physical activity in this age group. Methods Findings are based on 149 toddlers (19.0 ± 1.9 months and their parents (33.7 ± 4.7 years recruited from immunization clinics in Edmonton, Canada as part of the Parents’ Role in Establishing healthy Physical activity and Sedentary behavior habits (PREPS project. Toddlers’ and parental demographic characteristics and toddlers’ television viewing, video/computer games, and overall screen time were measured via the PREPS parental questionnaire. Toddlers’ objectively measured sedentary time and physical activity (light, moderate to vigorous, and total were accelerometer-derived using Actigraph wGT3X-BT monitors. Simple and multiple linear regression models were conducted to examine associations. Results In the multiple linear regression models, toddlers’ age, toddlers’ sex (female versus male, toddlers’ race/ethnicity (other versus European-Canadian/Caucasian, and household income ($50,001 to $100,000 versus > $100,000 were significantly positively associated, and main type of child care (child care center versus parental care was significantly negatively associated with screen time. Similar findings were observed with television viewing, except null associations were observed for toddlers’ sex. Toddlers’ race/ethnicity (other versus European-Canadian/Caucasian was significantly positively associated and main type of child care (child care

  18. Rotation and solvation of ammonium ion

    International Nuclear Information System (INIS)

    Perrin, C.L.; Gipe, R.K.

    1987-01-01

    From nitrogen-15 spin-lattice relaxation times and nuclear Overhauser enhancements, the rotational correlations time tau/sub c/ for 15 NH 4 + was determined in s series of solvents. Values of tau/sub c/ range from 0.46 to 20 picoseconds. The solvent dependent of tau/sub c/ cannot be explained in terms of solvent polarity, molecular dipole moment, solvent basicity, solvent dielectric relaxation, or solvent viscosity. The rapid rotation and the variation with solvent can be accounted for by a model that involves hydrogen bonding of an NH proton to more than one solvent molecule in a disordered solvation environment. 25 references, 1 table

  19. Amplitudes of solar p modes: Modelling of the eddy time-correlation function

    Energy Technology Data Exchange (ETDEWEB)

    Belkacem, K [Institut d' Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout 17-B 4000 Liege (Belgium); Samadi, R; Goupil, M J, E-mail: Kevin.Belkacem@ulg.ac.BE [LESIA, UMR8109, Universite Pierre et Marie Curie, Universite Denis Diderot, Obs. de Paris, 92195 Meudon Cedex (France)

    2011-01-01

    Modelling amplitudes of stochastically excited oscillations in stars is a powerful tool for understanding the properties of the convective zones. For instance, it gives us information on the way turbulent eddies are temporally correlated in a very large Reynolds number regime. We discuss the way the time correlation between eddies is modelled and we present recent theoretical developments as well as observational results. Eventually, we discuss the physical underlying meaning of the results by introducing the Ornstein-Uhlenbeck process, which is a sub-class of a Gaussian Markov process.

  20. Spectral density analysis of time correlation functions in lattice QCD using the maximum entropy method

    International Nuclear Information System (INIS)

    Fiebig, H. Rudolf

    2002-01-01

    We study various aspects of extracting spectral information from time correlation functions of lattice QCD by means of Bayesian inference with an entropic prior, the maximum entropy method (MEM). Correlator functions of a heavy-light meson-meson system serve as a repository for lattice data with diverse statistical quality. Attention is given to spectral mass density functions, inferred from the data, and their dependence on the parameters of the MEM. We propose to employ simulated annealing, or cooling, to solve the Bayesian inference problem, and discuss the practical issues of the approach

  1. Detection of rheumatoid arthritis by evaluation of normalized variances of fluorescence time correlation functions

    Science.gov (United States)

    Dziekan, Thomas; Weissbach, Carmen; Voigt, Jan; Ebert, Bernd; MacDonald, Rainer; Bahner, Malte L.; Mahler, Marianne; Schirner, Michael; Berliner, Michael; Berliner, Birgitt; Osel, Jens; Osel, Ilka

    2011-07-01

    Fluorescence imaging using the dye indocyanine green as a contrast agent was investigated in a prospective clinical study for the detection of rheumatoid arthritis. Normalized variances of correlated time series of fluorescence intensities describing the bolus kinetics of the contrast agent in certain regions of interest were analyzed to differentiate healthy from inflamed finger joints. These values are determined using a robust, parameter-free algorithm. We found that the normalized variance of correlation functions improves the differentiation between healthy joints of volunteers and joints with rheumatoid arthritis of patients by about 10% compared to, e.g., ratios of areas under the curves of raw data.

  2. How strongly do word reading times and lexical decision times correlate? Combining data from eye movement corpora and megastudies.

    Science.gov (United States)

    Kuperman, Victor; Drieghe, Denis; Keuleers, Emmanuel; Brysbaert, Marc

    2013-01-01

    We assess the amount of shared variance between three measures of visual word recognition latencies: eye movement latencies, lexical decision times, and naming times. After partialling out the effects of word frequency and word length, two well-documented predictors of word recognition latencies, we see that 7-44% of the variance is uniquely shared between lexical decision times and naming times, depending on the frequency range of the words used. A similar analysis of eye movement latencies shows that the percentage of variance they uniquely share either with lexical decision times or with naming times is much lower. It is 5-17% for gaze durations and lexical decision times in studies with target words presented in neutral sentences, but drops to 0.2% for corpus studies in which eye movements to all words are analysed. Correlations between gaze durations and naming latencies are lower still. These findings suggest that processing times in isolated word processing and continuous text reading are affected by specific task demands and presentation format, and that lexical decision times and naming times are not very informative in predicting eye movement latencies in text reading once the effect of word frequency and word length are taken into account. The difference between controlled experiments and natural reading suggests that reading strategies and stimulus materials may determine the degree to which the immediacy-of-processing assumption and the eye-mind assumption apply. Fixation times are more likely to exclusively reflect the lexical processing of the currently fixated word in controlled studies with unpredictable target words rather than in natural reading of sentences or texts.

  3. Neonatal periventricular leukomalacia: real-time sonographic diagnosis with CT correlation

    International Nuclear Information System (INIS)

    Chow, P.P.; Horgan, J.G.; Taylor, K.J.W.

    1985-01-01

    The utility of real-time sonography in the diagnosis of neonatal periventricular leukomalacia (PVL) has been described only recently. Six cases are reported of PVL diagnosed by serial real-time scanning. The sonographic findings were correlated with the computed tomographic findings and the clinical history. In five of six infants in whom scanning was performed, characteristic multiseptated periventricular cavitations developed 2-3 weeks after birth or later. A transition from normal to increased periventricular echogenicity was often observed before the development of the periventricular cavitations in nonhemorrhagic PVL. The parenchymal abnormality demonstrated by sonography correlated well with an abnormal neurologic outcome. It is suggested that serial real-time scanning be performed in neonates whose history suggests the possibility of hypoxic-ischemic brain injury. Nonspecific predictors of PVL include seizures, apnea, disturbed mental status, abnormal muscle tone, and leg weakness

  4. Phi-s correlation and dynamic time warping - Two methods for tracking ice floes in SAR images

    Science.gov (United States)

    Mcconnell, Ross; Kober, Wolfgang; Kwok, Ronald; Curlander, John C.; Pang, Shirley S.

    1991-01-01

    The authors present two algorithms for performing shape matching on ice floe boundaries in SAR (synthetic aperture radar) images. These algorithms quickly produce a set of ice motion and rotation vectors that can be used to guide a pixel value correlator. The algorithms match a shape descriptor known as the Phi-s curve. The first algorithm uses normalized correlation to match the Phi-s curves, while the second uses dynamic programming to compute an elastic match that better accommodates ice floe deformation. Some empirical data on the performance of the algorithms on Seasat SAR images are presented.

  5. Rates and timing of vertical-axis block rotations across the Sierra Nevada-Walker Lane transition in the Bodie Hills

    Science.gov (United States)

    Rood, D. H.; Herman, S.; Burbank, D.; Bogue, S.

    2008-12-01

    We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotation across the Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. In zones of continental deformation, block rotations are an important mechanism for permanent stain accommodation, and thus may be crucial to testing geodetic block models and resolving geologic-geodetic slip discrepancies. In our study, data included in the paleomagetic site means are high quality AF demagnetization results (least squared fits that generally include 5-7 points with MAD values less than 1). Thermal demagnetization results match the AF directions, and both thermal demag and rockmag results indicate strong ChRM, mostly carried by single domain magnetite. The site means used to calculate the VGPs all have a95 values less than 10 (mostly 2-5) and include 6-11 sites each. Each site (and thus site mean) has a reasonably well-known structural correction. The VGP scatter values range from 12 to 16 degrees, indicating that they include appropriate secular variation. The mean declinations and 95 percent confidence limits for each VGP timeslice are statistically distinct from one another (71 ± 9, 39 ± 13, and 11 ± 11 degrees). The slope of a linear regression fit to the age versus declination data gives a rate of vertical axis block rotation of approximately 3-4 degrees/Myr. Fitting two separate lines to the age vs. declination data would indicate an increase in the rates of rotation since ~10 Ma. Two possible interpretations of the data are: (1) the rotations began during or before the Middle Miocene, or (2) rates of rotation were high initially (e.g. ~10 Ma) and decelerated until the Pliocene. These data have implications for the (1) timing and spatial extent of distributed strain accumulation related to the initiation of the San Andreas Fault-Eastern California Shear Zone-Walker Lane transform plate boundary, (2) transfer of transform plate boundary

  6. A new methodology for measuring time correlations and excite states of atoms and nuclei

    International Nuclear Information System (INIS)

    Cavalcante, M.A.

    1989-01-01

    A system for measuring time correlation of physical phenomena events in the range of 10 -7 to 10 5 sec is proposed, and his results presented. This system, is based on a sequential time scale which is controlled by a precision quartz oscillator; the zero time of observation is set by means of a JK Flip-Flop, which is operated by a negative transition of pulse in coincidence with the pulse from a detector which marks the time zero of the event (precedent pulse). This electronic system (named digital chronoanalizer) was used in the measurement of excited states of nuclei as well as for the determination of time fluctuations in physical phenomena, such as the time lag in a halogen Geiger counter and is the measurement of the 60 KeV excited state of N P 237 . (author)

  7. The time-varying correlation between policy uncertainty and stock returns: Evidence from China

    Science.gov (United States)

    Xiong, Xiong; Bian, Yuxiang; Shen, Dehua

    2018-06-01

    In this paper, we use a new policy uncertainty index to investigate the time-varying correlation between economic policy uncertainty (EPU) and Chinese stock market returns. The correlation is examined in the period from January 1995 to December 2016. We show that absolute changes in EPU have a significant impact on stock market returns. Specifically, empirical results based on the DCC-GARCH model reveal that the correlation between EPU and stock returns has large fluctuations, especially during a financial crisis; in addition, the impact of EPU on the Shanghai stock market is greater than on the Shenzhen stock market. Robustness results reveal that the impact of EPU on state-owned enterprises is larger than on non-state enterprises. All of these results highlight the important role of EPU in the Chinese stock market, and shed light on such issues for future research.

  8. Time-varying correlations in global real estate markets: A multivariate GARCH with spatial effects approach

    Science.gov (United States)

    Gu, Huaying; Liu, Zhixue; Weng, Yingliang

    2017-04-01

    The present study applies the multivariate generalized autoregressive conditional heteroscedasticity (MGARCH) with spatial effects approach for the analysis of the time-varying conditional correlations and contagion effects among global real estate markets. A distinguishing feature of the proposed model is that it can simultaneously capture the spatial interactions and the dynamic conditional correlations compared with the traditional MGARCH models. Results reveal that the estimated dynamic conditional correlations have exhibited significant increases during the global financial crisis from 2007 to 2009, thereby suggesting contagion effects among global real estate markets. The analysis further indicates that the returns of the regional real estate markets that are in close geographic and economic proximities exhibit strong co-movement. In addition, evidence of significantly positive leverage effects in global real estate markets is also determined. The findings have significant implications on global portfolio diversification opportunities and risk management practices.

  9. Nonlinear Analysis on Cross-Correlation of Financial Time Series by Continuum Percolation System

    Science.gov (United States)

    Niu, Hongli; Wang, Jun

    We establish a financial price process by continuum percolation system, in which we attribute price fluctuations to the investors’ attitudes towards the financial market, and consider the clusters in continuum percolation as the investors share the same investment opinion. We investigate the cross-correlations in two return time series, and analyze the multifractal behaviors in this relationship. Further, we study the corresponding behaviors for the real stock indexes of SSE and HSI as well as the liquid stocks pair of SPD and PAB by comparison. To quantify the multifractality in cross-correlation relationship, we employ multifractal detrended cross-correlation analysis method to perform an empirical research for the simulation data and the real markets data.

  10. Neural correlates of belief-bias reasoning under time pressure: a near-infrared spectroscopy study.

    Science.gov (United States)

    Tsujii, Takeo; Watanabe, Shigeru

    2010-04-15

    The dual-process theory of reasoning explained the belief-bias effect, the tendency for human reasoning to be erroneously biased when logical conclusions are incongruent with belief about the world, by proposing a belief-based fast heuristic system and a logic-based slow analytic system. Although the claims were supported by behavioral findings that the belief-bias effect was enhanced when subjects were not given sufficient time for reasoning, the neural correlates were still unknown. The present study therefore examined the relationship between the time-pressure effect and activity in the inferior frontal cortex (IFC) during belief-bias reasoning using near-infrared spectroscopy (NIRS). Forty-eight subjects performed congruent and incongruent reasoning tasks, involving long-span (20 s) and short-span trials (10 s). Behavioral analysis found that only incongruent reasoning performance was impaired by the time-pressure of short-span trials. NIRS analysis found that the time-pressure decreased right IFC activity during incongruent trials. Correlation analysis showed that subjects with enhanced right IFC activity could perform better in incongruent trials, while subjects for whom the right IFC activity was impaired by the time-pressure could not maintain better reasoning performance. These findings suggest that the right IFC may be responsible for the time-pressure effect in conflicting reasoning processes. When the right IFC activity was impaired in the short-span trials in which subjects were not given sufficient time for reasoning, the subjects may rely on the fast heuristic system, which result in belief-bias responses. We therefore offer the first demonstration of neural correlates of time-pressure effect on the IFC activity in belief-bias reasoning. Copyright 2009 Elsevier Inc. All rights reserved.

  11. Econophysics — complex correlations and trend switchings in financial time series

    Science.gov (United States)

    Preis, T.

    2011-03-01

    This article focuses on the analysis of financial time series and their correlations. A method is used for quantifying pattern based correlations of a time series. With this methodology, evidence is found that typical behavioral patterns of financial market participants manifest over short time scales, i.e., that reactions to given price patterns are not entirely random, but that similar price patterns also cause similar reactions. Based on the investigation of the complex correlations in financial time series, the question arises, which properties change when switching from a positive trend to a negative trend. An empirical quantification by rescaling provides the result that new price extrema coincide with a significant increase in transaction volume and a significant decrease in the length of corresponding time intervals between transactions. These findings are independent of the time scale over 9 orders of magnitude, and they exhibit characteristics which one can also find in other complex systems in nature (and in physical systems in particular). These properties are independent of the markets analyzed. Trends that exist only for a few seconds show the same characteristics as trends on time scales of several months. Thus, it is possible to study financial bubbles and their collapses in more detail, because trend switching processes occur with higher frequency on small time scales. In addition, a Monte Carlo based simulation of financial markets is analyzed and extended in order to reproduce empirical features and to gain insight into their causes. These causes include both financial market microstructure and the risk aversion of market participants.

  12. [Working time and sleep in nursing staff employed in "3 x 8" and "2 x 12" fast rotating shift schedules].

    Science.gov (United States)

    Castellini, G; Anelli, M M; Punzi, S; Boari, P; Camerino, D; Costa, G

    2011-01-01

    The study is aimed at assessing, in 200 nurses shift workers, the impact on sleep of two different working areas ("emergency" and "hospitalization") having the same "3 x 8" shift system, and of two different shift schedules at quick rotation ("2 x 12" and "3 x 8") in the same working area ("emergency"). Night and morning shifts prove to interfere to a greater extent with sleep in relation to both "2 x 12" and "3 x 8" shift systems as well as to the two operative areas. Hence the importance to consider in shift work planning, the direction of shift rotation and the length of the duty period according to the type of activity.

  13. Correlating interfacial octahedral rotations with magnetism in (LaMnO3+δ)N/(SrTiO3)N superlattices.

    Science.gov (United States)

    Zhai, Xiaofang; Cheng, Long; Liu, Yang; Schlepütz, Christian M; Dong, Shuai; Li, Hui; Zhang, Xiaoqiang; Chu, Shengqi; Zheng, Lirong; Zhang, Jing; Zhao, Aidi; Hong, Hawoong; Bhattacharya, Anand; Eckstein, James N; Zeng, Changgan

    2014-07-09

    Lattice distortion due to oxygen octahedral rotations have a significant role in mediating the magnetism in oxides, and recently attracts a lot of interests in the study of complex oxides interface. However, the direct experimental evidence for the interrelation between octahedral rotation and magnetism at interface is scarce. Here we demonstrate that interfacial octahedral rotation are closely linked to the strongly modified ferromagnetism in (LaMnO3+δ)N/(SrTiO3)N superlattices. The maximized ferromagnetic moment in the N=6 superlattice is accompanied by a metastable structure (space group Imcm) featuring minimal octahedral rotations (a(-)a(-)c(-), α~4.2°, γ~0.5°). Quenched ferromagnetism for Nmagnetism. Our study demonstrates that engineering superlattices with controllable interfacial structures can be a feasible new route in realizing functional magnetic materials.

  14. Improving the counting efficiency in time-correlated single photon counting experiments by dead-time optimization

    Energy Technology Data Exchange (ETDEWEB)

    Peronio, P.; Acconcia, G.; Rech, I.; Ghioni, M. [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2015-11-15

    Time-Correlated Single Photon Counting (TCSPC) has been long recognized as the most sensitive method for fluorescence lifetime measurements, but often requiring “long” data acquisition times. This drawback is related to the limited counting capability of the TCSPC technique, due to pile-up and counting loss effects. In recent years, multi-module TCSPC systems have been introduced to overcome this issue. Splitting the light into several detectors connected to independent TCSPC modules proportionally increases the counting capability. Of course, multi-module operation also increases the system cost and can cause space and power supply problems. In this paper, we propose an alternative approach based on a new detector and processing electronics designed to reduce the overall system dead time, thus enabling efficient photon collection at high excitation rate. We present a fast active quenching circuit for single-photon avalanche diodes which features a minimum dead time of 12.4 ns. We also introduce a new Time-to-Amplitude Converter (TAC) able to attain extra-short dead time thanks to the combination of a scalable array of monolithically integrated TACs and a sequential router. The fast TAC (F-TAC) makes it possible to operate the system towards the upper limit of detector count rate capability (∼80 Mcps) with reduced pile-up losses, addressing one of the historic criticisms of TCSPC. Preliminary measurements on the F-TAC are presented and discussed.

  15. Only so Many Hours: Correlations between Personality and Daily Time Use in a Representative German Panel

    Directory of Open Access Journals (Sweden)

    Julia M. Rohrer

    2018-01-01

    Full Text Available Time is a finite resource, strictly limited to 24 hours a day. How people spend these resources is in many ways determined by necessities and external constraints, yet research on personality-situation transactions shows that people also choose their environments to resonate with their personality. This finding implies that daily time use and individual traits should be correlated. However, few studies have linked modern methods for assessing time use to individual differences in personality traits. In this study, we investigate correlations between the Big Five traits and time spent on various daily activities in the German Socio-Economic Panel (SOEP, including 5,456 days in the lives of 1,364 individuals. Results converged towards previously reported personality-situation transactions. For example, extraversion predicted whether or not respondents reported meeting their friends, whereas openness was correlated negatively with watching TV. Effects were modest in size, ranging from r~~.10 to .25. Taking together, our findings corroborate the notion that our personality is robustly associated with the way we spend our lives.

  16. Ignition delay time correlation of fuel blends based on Livengood-Wu description

    KAUST Repository

    Khaled, Fathi

    2017-08-17

    In this work, a universal methodology for ignition delay time (IDT) correlation of multicomponent fuel mixtures is reported. The method is applicable over wide ranges of temperatures, pressures, and equivalence ratios. n-Heptane, iso-octane, toluene, ethanol and their blends are investigated in this study because of their relevance to gasoline surrogate formulation. The proposed methodology combines benefits from the Livengood-Wu integral, the cool flame characteristics and the Arrhenius behavior of the high-temperature ignition delay time to suggest a simple and comprehensive formulation for correlating the ignition delay times of pure components and blends. The IDTs of fuel blends usually have complex dependences on temperature, pressure, equivalence ratio and composition of the blend. The Livengood-Wu integral is applied here to relate the NTC region and the cool flame phenomenon. The integral is further extended to obtain a relation between the IDTs of fuel blends and pure components. Ignition delay times calculated using the proposed methodology are in excellent agreement with those simulated using a detailed chemical kinetic model for n-heptane, iso-octane, toluene, ethanol and blends of these components. Finally, very good agreement is also observed for combustion phasing in homogeneous charge compression ignition (HCCI) predictions between simulations performed with detailed chemistry and calculations using the developed ignition delay correlation.

  17. Neuroanatomical correlates of time perspective: A voxel-based morphometry study.

    Science.gov (United States)

    Chen, Zhiyi; Guo, Yiqun; Feng, Tingyong

    2018-02-26

    Previous studies indicated that time perspective can affect many behaviors, such as decisions, risk taking, substance abuse and health behaviors. However, very little is known about the neural substrates of time perspective (TP). To address this question, we characterized different dimensions of TP (including the Past, Present, and Future TP) using standardized Zimbardo Time Perspective Inventory (ZTPI), and quantified the gray matter volume using voxel-based morphometry (VBM) method across two independent samples. Our whole-brain analysis (sample 1, N=150) revealed Past-Negative TP was positively correlated with the GMV of a cluster in LPFC whereas Past-Positive was negatively correlated with the GMV in OFC, and Future TP was negatively correlated with GMV in mPFC. Moreover, two present scales (Present-Hedonistic and Present-Fatalistic TPs) were positively correlated with the GMV of regions in MTG and precuneus, respectively. We further examined the reliability of these correlations between multidimensional TPs and neuroanatomical structures in another independent sample (sample 2, N=58). Results verified our findings that GMV in LPFC could predict Past-Negative TP while GMV in OFC could predict Past-Positive TP, and the GMV in MTG could predict Present-Hedonistic while the GMV in presuneus could predict Present-Fatalistic, as well as the GMV in mPFC could predict Future TP. Thus, our findings suggest that the existence of selective neural basis underlying TPs, and further provide the stable biomarkers for multidimensional TPs. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Lyapunov Exponent and Out-of-Time-Ordered Correlator's Growth Rate in a Chaotic System.

    Science.gov (United States)

    Rozenbaum, Efim B; Ganeshan, Sriram; Galitski, Victor

    2017-02-24

    It was proposed recently that the out-of-time-ordered four-point correlator (OTOC) may serve as a useful characteristic of quantum-chaotic behavior, because, in the semiclassical limit ℏ→0, its rate of exponential growth resembles the classical Lyapunov exponent. Here, we calculate the four-point correlator C(t) for the classical and quantum kicked rotor-a textbook driven chaotic system-and compare its growth rate at initial times with the standard definition of the classical Lyapunov exponent. Using both quantum and classical arguments, we show that the OTOC's growth rate and the Lyapunov exponent are, in general, distinct quantities, corresponding to the logarithm of the phase-space averaged divergence rate of classical trajectories and to the phase-space average of the logarithm, respectively. The difference appears to be more pronounced in the regime of low kicking strength K, where no classical chaos exists globally. In this case, the Lyapunov exponent quickly decreases as K→0, while the OTOC's growth rate may decrease much slower, showing a higher sensitivity to small chaotic islands in the phase space. We also show that the quantum correlator as a function of time exhibits a clear singularity at the Ehrenfest time t_{E}: transitioning from a time-independent value of t^{-1}lnC(t) at ttime at t>t_{E}. We note that the underlying physics here is the same as in the theory of weak (dynamical) localization [Aleiner and Larkin, Phys. Rev. B 54, 14423 (1996)PRBMDO0163-182910.1103/PhysRevB.54.14423; Tian, Kamenev, and Larkin, Phys. Rev. Lett. 93, 124101 (2004)PRLTAO0031-900710.1103/PhysRevLett.93.124101] and is due to a delay in the onset of quantum interference effects, which occur sharply at a time of the order of the Ehrenfest time.

  19. Hand-operated and rotary ProTaper instruments: a comparison of working time and number of rotations in simulated root canals.

    Science.gov (United States)

    Pasqualini, Damiano; Scotti, Nicola; Tamagnone, Lorenzo; Ellena, Federica; Berutti, Elio

    2008-03-01

    The aim of this study was to compare the effective shaping time and number of rotations required by an endodontist working with hand and rotary ProTaper instruments to completely shape simulated root canals. Eighty Endo Training Blocks (curved canal shape) were used. Manual preflaring was performed with K-Flexofiles #08-10-12-15-17 and #20 Nitiflex at a working length of 18 mm. Specimens were then randomly assigned to 2 different groups (n = 40); group 1 was shaped by using hand ProTaper and group 2 with ProTaper rotary. The number of rotations made in the canal and the effective time required to achieve complete canal shaping were recorded for each instrument. Differences between groups were analyzed with the nonparametric Mann-Whitney U test (P Hand ProTaper required significantly fewer rotations (P ProTaper, whereas the effective working time to fully shape the simulated canal was significantly higher (P hand ProTaper.

  20. Diffusion and superdiffusion of a particle in a random potential with finite correlation time

    International Nuclear Information System (INIS)

    Lebedev, N.; Maass, P.; Feng, S.

    1995-01-01

    We study theoretically the long time asymptotic of a quantum particle moving in a random time-dependent potential with finite correlation time, in d=1. By applying a new unitary numerical scheme we first show the minor importance of quantum interference and then derive an effective Langevin-type equation for the corresponding clasical problem in the limit of weak potential. We find that on intermediate time scales E kin (t)∼t 2/5 , while the true long time asymptotic is determined by a new friction term, which gives rise to a stationary power law velocity distribution, multifractality of the velocity moments, and a slowing down of the superdiffusive behavior

  1. Correlation between use time of machine and decline curve for emerging enterprise information systems

    Science.gov (United States)

    Chang, Yao-Chung; Lai, Chin-Feng; Chuang, Chi-Cheng; Hou, Cheng-Yu

    2018-04-01

    With the progress of science and technology, more and more machines are adpot to help human life better and more convenient. When the machines have been used for a longer period of time so that the machine components are getting old, the amount of power comsumption will increase and easily cause the machine to overheat. This also causes a waste of invisible resources. If the Internet of Everything (IoE) technologies are able to be applied into the enterprise information systems for monitoring the machines use time, it can not only make energy can be effectively used, but aslo create a safer living environment. To solve the above problem, the correlation predict model is established to collect the data of power consumption converted into power eigenvalues. This study takes the power eigenvalue as the independent variable and use time as the dependent variable in order to establish the decline curve. Ultimately, the scoring and estimation modules are employed to seek the best power eigenvalue as the independent variable. To predict use time, the correlation is discussed between the use time and the decline curve to improve the entire behavioural analysis of the facilitate recognition of the use time of machines.

  2. EEG correlates of cognitive time scales in the Necker-Zeno model for bistable perception.

    Science.gov (United States)

    Kornmeier, J; Friedel, E; Wittmann, M; Atmanspacher, H

    2017-08-01

    The Necker-Zeno model of bistable perception provides a formal relation between the average duration of meta-stable percepts (dwell times T) of ambiguous figures and two other basic time scales (t 0 , ΔT) underlying cognitive processing. The model predicts that dwell times T covary with t 0 , ΔT or both. We tested this prediction by exploiting that observers, in particular experienced meditators, can volitionally control dwell times T. Meditators and non-meditators observed bistable Necker cubes either passively or tried to hold their current percept. The latencies of a centro-parietal event-related potential (CPP) were recorded as a physiological correlate of t 0 . Dwell times T and the CPP latencies, correlated with t 0 , differed between conditions and observer groups, while ΔT remained constant in the range predicted by the model. The covariation of CPP latencies and dwell times, as well as their quadratic functional dependence extends previous psychophysical confirmation of the Necker-Zeno model to psychophysiological measures. Copyright © 2017. Published by Elsevier Inc.

  3. Time-of-flight spectrometer for the measurement of gamma correlated neutron spectra

    International Nuclear Information System (INIS)

    Andriashin, A.V.; Devkin, B.V.; Lychagin, A.A.; Minko, J.V.; Mironov, A.N.; Nesterenko, V.S.; Sztaricskai, T.; Petoe, G.; Vasvary, L.

    1986-01-01

    A time-of-flight spectrometer for the measurement of gamma correlated neutron spectra from (n,xnγ) reactions is described. The operation and the main parameters are discussed. The resolution in the neutron channel is 2.2 ns/m at the 150 keV neutron energy threshold. A simultaneous measurement of the time-of-flight and amplitude distributions makes it possible to study gamma correlated neutron spectra as well as the prompt gamma spectra in coincidence with selected energy neutrons. In order to test the spectrometer, measurements of the neutron spectrum in coincidence with the 846 keV gamma line of 56 Fe were carried out at an incident neutron energy of 14.1 MeV. (Auth.)

  4. Time-of-flight spectrometer for the measurement of gamma correlated neutron spectra

    International Nuclear Information System (INIS)

    Andryashin, A.V.; Devlein, B.V.; Lychagin, A.A.; Minko, Y.V.; Mironov, A.N.; Nesterenko, V.S.

    1986-01-01

    A time-of-flight spectrometer for the measurement of gamma correlated neutron spectra form (n,xnγ) reactions is described. The operation and the main parameters are discussed. The resolution in the neutron channel is 2.2 ns/m at the 150 keV neutron energy threshold. A simultaneous measurement of the time-of-flight and amplitude distributions makes it possible to study gamma correlated neutron spectra as well as the prompt gamma spectra in coincidence with selected energy neutrons. In order to test the spectrometer, measurements of the neutron spectrum in coincidence with the 846 keV gamma line of 56 Fe were carried out at an incident neutron energy of 14.1 MeV. (author). 3 figs., 6 refs

  5. Venous filling time using air-plethysmography correlates highly with great saphenous vein reflux time using duplex.

    Science.gov (United States)

    Lattimer, C R; Azzam, M; Kalodiki, E; Geroulakos, G

    2014-03-01

    Venous filling time (VFT90) is the time taken to reach 90% of the venous volume in the calf. It is recorded by air-plethysmography (APG(®)) and is assumed to measure global venous reflux duration. However, this has never been confirmed by duplex. The aim of the study was to compare VFT on APG to venous reflux time/duration (RT) measured simultaneously with duplex on the same patients. Twenty-six consecutive patients, M:F = 16:10, age (25-78), C1 = 1, C2 = 4, C3 = 8, C4a = 6, C4b = 4, C5 = 2, C6 = 1, underwent simultaneous APG with duplex. The venous filling index (VFI, mL/second), VFT90 (seconds), great saphenous vein (GSV) RT on duplex, averaged thigh GSV diameter and thigh length (length) between the APG sensor air-cuff and duplex transducer were recorded. The VFT100 was calculated by VFT90/0.9. The additional time taken to fill the thigh was achieved using the VFI, length and deep vein diameter (d), to determine the corrected reflux duration: CRD = VFT100 + (length × πd(2)/4 (1/VFI)). Twenty-five patients are presented. One patient with very mild reflux (VFT90 = 55.9 seconds) had an indeterminate endpoint on duplex and was excluded. The median (range) VFI and GSV diameter was 4.9(1.3-15.5) mL/second and 7(4-17) mm, respectively. The VFT90 and VFT100 both correlated with RT on duplex (Spearman, P duplex RT at 24 (16.9) versus 28 (20) seconds respectively, P duplex by performing simultaneous measurements. There was an excellent correlation between the VFT90 versus duplex RT, thereby comparing reverse flow in a single superficial vein against the legs overall venous haemodynamic status. These tests can both be used in the quantification of reflux.

  6. Time correlation measurements from extensive air showers detected by the EEE telescopes

    CERN Document Server

    Abbrescia, M; Fabbri, F L; Gnesi, I; Bressan, E; Tosello, F; Librizzi, F; Coccia, E; Paoletti, R; Yanez, G; Li, S; Votano, L; Scribano, A; Avanzini, C; Piragino, G; Perasso, L; Regano, A; Ferroli, R Baldini; De Gruttola, D; Sartorelli, G; Siddi, E; Cifarelli, L; Di Giovanni, A; Frolov, V; Serci, S; Selvi, M; Zouyevski, R; Dreucci, M; Squarcia, S; Righini, G C; Agocs, A; Zichichi, A; La Rocca, P; Pilo, F; Miozzi, S; Massai, M; Cicalo, C; D'Incecco, M; Panareo, M; Gemme, G; Garbini, M; Aiola, S; Riggi, F; Hatzifotiadou, D; Scapparone, E; Chiavassa, A; Maggiora, A; Bencivenni, G; Gustavino, C; Spandre, G; Taiuti, M; Williams, M C S; Bossini, E; De Pasquale, S

    2013-01-01

    Time correlated events due to cosmic muons from extensive air showers have been detected by means of telescope pairs of the EEE (Extreme Energy Events) Project array. The coincidence rate, properly normalized for detector acceptance, efficiency and altitude location, has been extracted as a function of the relative distance between the telescopes. The results have been also compared with additional measurements carried out by small scintillator detectors at various distances.

  7. Correlated continuous-time random walks—scaling limits and Langevin picture

    International Nuclear Information System (INIS)

    Magdziarz, Marcin; Metzler, Ralf; Szczotka, Wladyslaw; Zebrowski, Piotr

    2012-01-01

    In this paper we analyze correlated continuous-time random walks introduced recently by Tejedor and Metzler (2010 J. Phys. A: Math. Theor. 43 082002). We obtain the Langevin equations associated with this process and the corresponding scaling limits of their solutions. We prove that the limit processes are self-similar and display anomalous dynamics. Moreover, we extend the model to include external forces. Our results are confirmed by Monte Carlo simulations

  8. Correlates of Leisure-Time Physical Activity Participation Among Latino Children and Adolescents with Acanthosis Nigricans.

    Science.gov (United States)

    Wen, Ming; Su, Dejun

    2015-10-01

    Little is known about leisure-time physical activity (LTPA) correlates in high-risk youth prone to obesity, insulin resistance, and associated morbidities. This study examined LTPA correlates among Latino youth identified with acanthosis nigricans (AN), a skin condition typically caused by metabolic impairment. Data were collected on 305 AN-positive Latino youth of ages 5-15 and one of their biological parents in 2012 from Texas. Ordinal logit regression was performed to analyze the data. Five health and behavioral LTPA correlates were identified, including child time spent in TV watching or videogame playing (OR of highest quartile vs. lowest quartile = 0.45; p = 0.01), child fair/poor health (OR 0.42; p = 0.01), parent obesity (OR 0.63; p = 0.06), parent daily physical exercise for more than 30 min (OR 2.20; p < 0.01), and parent housework time (OR 0.76; p < 0.05). Parent socioeconomic status was insignificant. For at-risk Latino youth, physical activity intervention strategies should take both behavioral and health factors into account.

  9. Linearized semiclassical initial value time correlation functions with maximum entropy analytic continuation.

    Science.gov (United States)

    Liu, Jian; Miller, William H

    2008-09-28

    The maximum entropy analytic continuation (MEAC) method is used to extend the range of accuracy of the linearized semiclassical initial value representation (LSC-IVR)/classical Wigner approximation for real time correlation functions. LSC-IVR provides a very effective "prior" for the MEAC procedure since it is very good for short times, exact for all time and temperature for harmonic potentials (even for correlation functions of nonlinear operators), and becomes exact in the classical high temperature limit. This combined MEAC+LSC/IVR approach is applied here to two highly nonlinear dynamical systems, a pure quartic potential in one dimensional and liquid para-hydrogen at two thermal state points (25 and 14 K under nearly zero external pressure). The former example shows the MEAC procedure to be a very significant enhancement of the LSC-IVR for correlation functions of both linear and nonlinear operators, and especially at low temperature where semiclassical approximations are least accurate. For liquid para-hydrogen, the LSC-IVR is seen already to be excellent at T=25 K, but the MEAC procedure produces a significant correction at the lower temperature (T=14 K). Comparisons are also made as to how the MEAC procedure is able to provide corrections for other trajectory-based dynamical approximations when used as priors.

  10. Nonlinear stochastic exclusion financial dynamics modeling and time-dependent intrinsic detrended cross-correlation

    Science.gov (United States)

    Zhang, Wei; Wang, Jun

    2017-09-01

    In attempt to reproduce price dynamics of financial markets, a stochastic agent-based financial price model is proposed and investigated by stochastic exclusion process. The exclusion process, one of interacting particle systems, is usually thought of as modeling particle motion (with the conserved number of particles) in a continuous time Markov process. In this work, the process is utilized to imitate the trading interactions among the investing agents, in order to explain some stylized facts found in financial time series dynamics. To better understand the correlation behaviors of the proposed model, a new time-dependent intrinsic detrended cross-correlation (TDI-DCC) is introduced and performed, also, the autocorrelation analyses are applied in the empirical research. Furthermore, to verify the rationality of the financial price model, the actual return series are also considered to be comparatively studied with the simulation ones. The comparison results of return behaviors reveal that this financial price dynamics model can reproduce some correlation features of actual stock markets.

  11. A time correlation function theory describing static field enhanced third order optical effects at interfaces.

    Science.gov (United States)

    Neipert, Christine; Space, Brian

    2006-12-14

    Sum vibrational frequency spectroscopy, a second order optical process, is interface specific in the dipole approximation. At charged interfaces, there exists a static field, and as a direct consequence, the experimentally detected signal is a combination of enhanced second and static field induced third order contributions. There is significant evidence in the literature of the importance/relative magnitude of this third order contribution, but no previous molecularly detailed approach existed to separately calculate the second and third order contributions. Thus, for the first time, a molecularly detailed time correlation function theory is derived here that allows for the second and third order contributions to sum frequency vibrational spectra to be individually determined. Further, a practical, molecular dynamics based, implementation procedure for the derived correlation functions that describe the third order phenomenon is also presented. This approach includes a novel generalization of point atomic polarizability models to calculate the hyperpolarizability of a molecular system. The full system hyperpolarizability appears in the time correlation functions responsible for third order contributions in the presence of a static field.

  12. Empirical mode decomposition and long-range correlation analysis of sunspot time series

    International Nuclear Information System (INIS)

    Zhou, Yu; Leung, Yee

    2010-01-01

    Sunspots, which are the best known and most variable features of the solar surface, affect our planet in many ways. The number of sunspots during a period of time is highly variable and arouses strong research interest. When multifractal detrended fluctuation analysis (MF-DFA) is employed to study the fractal properties and long-range correlation of the sunspot series, some spurious crossover points might appear because of the periodic and quasi-periodic trends in the series. However many cycles of solar activities can be reflected by the sunspot time series. The 11-year cycle is perhaps the most famous cycle of the sunspot activity. These cycles pose problems for the investigation of the scaling behavior of sunspot time series. Using different methods to handle the 11-year cycle generally creates totally different results. Using MF-DFA, Movahed and co-workers employed Fourier truncation to deal with the 11-year cycle and found that the series is long-range anti-correlated with a Hurst exponent, H, of about 0.12. However, Hu and co-workers proposed an adaptive detrending method for the MF-DFA and discovered long-range correlation characterized by H≈0.74. In an attempt to get to the bottom of the problem in the present paper, empirical mode decomposition (EMD), a data-driven adaptive method, is applied to first extract the components with different dominant frequencies. MF-DFA is then employed to study the long-range correlation of the sunspot time series under the influence of these components. On removing the effects of these periods, the natural long-range correlation of the sunspot time series can be revealed. With the removal of the 11-year cycle, a crossover point located at around 60 months is discovered to be a reasonable point separating two different time scale ranges, H≈0.72 and H≈1.49. And on removing all cycles longer than 11 years, we have H≈0.69 and H≈0.28. The three cycle-removing methods—Fourier truncation, adaptive detrending and the

  13. Universal Earthquake-Occurrence Jumps, Correlations with Time, and Anomalous Diffusion

    International Nuclear Information System (INIS)

    Corral, Alvaro

    2006-01-01

    Spatiotemporal properties of seismicity are investigated for a worldwide (WW) catalog and for southern California in the stationary case (SC), showing a nearly universal scaling behavior. Distributions of distances between consecutive earthquakes (jumps) are magnitude independent and show two power-law regimes, separated by jump values about 200 (WW) and 15 km (SC). Distributions of waiting times conditioned to the value of jumps show that both variables are correlated, in general, but turn out to be independent when only short or long jumps are considered. Finally, diffusion profiles are found to be independent on the magnitude, contrary to what the waiting-time distributions suggest

  14. Exact Time-Dependent Exchange-Correlation Potential in Electron Scattering Processes

    Science.gov (United States)

    Suzuki, Yasumitsu; Lacombe, Lionel; Watanabe, Kazuyuki; Maitra, Neepa T.

    2017-12-01

    We identify peak and valley structures in the exact exchange-correlation potential of time-dependent density functional theory that are crucial for time-resolved electron scattering in a model one-dimensional system. These structures are completely missed by adiabatic approximations that, consequently, significantly underestimate the scattering probability. A recently proposed nonadiabatic approximation is shown to correctly capture the approach of the electron to the target when the initial Kohn-Sham state is chosen judiciously, and it is more accurate than standard adiabatic functionals but ultimately fails to accurately capture reflection. These results may explain the underestimation of scattering probabilities in some recent studies on molecules and surfaces.

  15. Correlation Between Timed Barium Esophagogram and Esophageal Transit Scintigraphy Results in Achalasia.

    Science.gov (United States)

    Park, Yoo Mi; Jeon, Han Ho; Park, Jae Jun; Kim, Jie-Hyun; Youn, Young Hoon; Park, Hyojin

    2015-08-01

    Timed barium esophagogram (TBE) and esophageal transit scintigraphy (ETS) have been adopted as useful ways to evaluate achalasia patients. TBE has merit as a simple, non-invasive, and convenient method. The study sought to compare the results of these two tests and verify their usefulness in evaluating treatment response. In addition, we assessed whether TBE could effectively replace ETS through correlation analysis. The medical records of 50 achalasia patients treated between September 2011 and June 2014 were reviewed retrospectively. The height and width of the barium column at 1, 2, and 5 min were measured by TBE. Half-life (T 1/2, min) and R 30 (percentage of remaining radioactivity 30 s after radioisotope ingestion) were measured by ETS. Both tests were performed before and after treatment, and the tests were carried out 1 and 2 days after procedures. And we analyzed the correlation between the parameters from the two tests. The parameters of TBE and ETS were improved after treatment (p treatment, the height and width results at 5 min from TBE positively correlated with the T 1/2 parameter from ETS (correlation coefficients of 0.59 and 0.75, respectively). After treatment, the correlation coefficients between the 5-min height and width of the barium column by TBE and T 1/2 by ETS were 0.55 and 0.46, respectively. Both TBE and ETS are useful modalities in assessing esophageal emptying and response to achalasia treatment. TBE and ETS results have a statistically significant correlation both pre- and post-treatment. We suggest that TBE could effectively replace ETS for the assessment of achalasia.

  16. Cerebellar Shaping of Motor Cortical Firing Is Correlated with Timing of Motor Actions

    Directory of Open Access Journals (Sweden)

    Abdulraheem Nashef

    2018-05-01

    Full Text Available Summary: In higher mammals, motor timing is considered to be dictated by cerebellar control of motor cortical activity, relayed through the cerebellar-thalamo-cortical (CTC system. Nonetheless, the way cerebellar information is integrated with motor cortical commands and affects their temporal properties remains unclear. To address this issue, we activated the CTC system in primates and found that it efficiently recruits motor cortical cells; however, the cortical response was dominated by prolonged inhibition that imposed a directional activation across the motor cortex. During task performance, cortical cells that integrated CTC information fired synchronous bursts at movement onset. These cells expressed a stronger correlation with reaction time than non-CTC cells. Thus, the excitation-inhibition interplay triggered by the CTC system facilitates transient recruitment of a cortical subnetwork at movement onset. The CTC system may shape neural firing to produce the required profile to initiate movements and thus plays a pivotal role in timing motor actions. : Nashef et al. identified a motor cortical subnetwork recruited by cerebellar volley that was transiently synchronized at movement onset. Cerebellar control of cortical firing was dominated by inhibition that shaped task-related firing of neurons and may dictate motor timing. Keywords: motor control, primates, cerebellar-thalamo-cortical, synchrony, noise correlation, reaction time

  17. Local wavelet correlation: applicationto timing analysis of multi-satellite CLUSTER data

    Directory of Open Access Journals (Sweden)

    J. Soucek

    2004-12-01

    Full Text Available Multi-spacecraft space observations, such as those of CLUSTER, can be used to infer information about local plasma structures by exploiting the timing differences between subsequent encounters of these structures by individual satellites. We introduce a novel wavelet-based technique, the Local Wavelet Correlation (LWC, which allows one to match the corresponding signatures of large-scale structures in the data from multiple spacecraft and determine the relative time shifts between the crossings. The LWC is especially suitable for analysis of strongly non-stationary time series, where it enables one to estimate the time lags in a more robust and systematic way than ordinary cross-correlation techniques. The technique, together with its properties and some examples of its application to timing analysis of bow shock and magnetopause crossing observed by CLUSTER, are presented. We also compare the performance and reliability of the technique with classical discontinuity analysis methods. Key words. Radio science (signal processing – Space plasma physics (discontinuities; instruments and techniques

  18. A general statistical test for correlations in a finite-length time series.

    Science.gov (United States)

    Hanson, Jeffery A; Yang, Haw

    2008-06-07

    The statistical properties of the autocorrelation function from a time series composed of independently and identically distributed stochastic variables has been studied. Analytical expressions for the autocorrelation function's variance have been derived. It has been found that two common ways of calculating the autocorrelation, moving-average and Fourier transform, exhibit different uncertainty characteristics. For periodic time series, the Fourier transform method is preferred because it gives smaller uncertainties that are uniform through all time lags. Based on these analytical results, a statistically robust method has been proposed to test the existence of correlations in a time series. The statistical test is verified by computer simulations and an application to single-molecule fluorescence spectroscopy is discussed.

  19. Attributions, future time perspective and career maturity in nursing undergraduates: correlational study design.

    Science.gov (United States)

    Cheng, Cheng; Yang, Liu; Chen, Yuxia; Zou, Huijing; Su, Yonggang; Fan, Xiuzhen

    2016-01-25

    Career maturity is an important parameter as nursing undergraduates prepare for their future careers. However, little is known regarding the relationships between attributions, future time perspective and career maturity among nursing undergraduates. The purpose of this study was to investigate the degree of career maturity and its relationship with attributions and future time perspective. A cross-sectional survey was designed. This survey was administered to 431 Chinese nursing undergraduates. Independent-sample t-tests and one-way ANOVA were performed to examine the mean differences between categories of binary and categorical demographic characteristics, respectively. Pearson correlations and multiple linear regressions were used to test the relationships between attributions, future time perspective and career maturity. The degree of career maturity was moderate among nursing undergraduates and that internal attributions of academic achievement, future efficacy and future purpose consciousness were positively associated with career maturity (all p time perspective and to facilitate their transition from school to clinical practice.

  20. Correlation between Chinese and international energy prices based on a HP filter and time difference analysis

    International Nuclear Information System (INIS)

    He, Yongxiu; Wang, Bing; Wang, Jianhui; Xiong, Wei; Xia, Tian

    2013-01-01

    To establish a reasonable system and mechanism for Chinese energy prices, we use the Granger causality test, Hodrick–Prescott (HP) filter and time difference analysis to research the pricing relationship between Chinese and international energy prices. We find that Chinese and international crude oil prices changed synchronously while Chinese refined oil prices follow the changes of international oil prices with the time difference being about 1 month to 2 months. Further, Australian coal prices Granger causes Chinese coal prices, and there is a high correlation between them. The U.S. electricity price is influenced by the WTI crude oil price, the U.S. gasoline price and the HenryHub gas price. Due to the unreasonable price-setting mechanism and regulation from the central government, China′s terminal market prices for both electricity and natural gas do not reflect the real supply–demand situation. This paper provides quantitative results on the correlation between Chinese and international energy prices to better predict the impact of international energy price fluctuations on China′s domestic energy supply and guide the design of more efficient energy pricing policies. Moreover, it provides references for developing countries to improve their energy market systems and trading, and to coordinate domestic and international energy markets. -- Highlights: •The Hodrick-Prescott filter and time difference analysis are used to research the correlation among energy prices. •Our study finds that the U.S. and British refined oil prices Granger cause the Chinese refined oil price. •Both Chinese and the Australian coal prices play an important role in the international coal market. •The Chinese terminal electric power and terminal natural gas prices are not highly correlated. •The results are useful for guiding the design of more efficient energy pricing policies in China

  1. Real-time finite-temperature correlators from AdS/CFT

    International Nuclear Information System (INIS)

    Barnes, Edwin; Vaman, Diana; Wu Chaolun; Arnold, Peter

    2010-01-01

    In this paper we use anti-de Sitter/conformal field theory correspondence ideas in conjunction with insights from finite-temperature real-time field theory formalism to compute 3-point correlators of N=4 super Yang-Mills operators, in real time and at finite temperature. To this end, we propose that the gravity field action is integrated only over the right and left quadrants of the Penrose diagram of the anti-de Sitter-Schwarzschild background, with a relative sign between the two terms. For concreteness we consider the case of a scalar field in the black hole background. Using the scalar field Schwinger-Keldysh bulk-to-boundary propagators, we give the general expression of a 3-point real-time Green's correlator. We then note that this particular prescription amounts to adapting the finite-temperature analog of Veltman's circling rules to tree-level Witten diagrams, and comment on the retarded and Feynman scalar bulk-to-boundary propagators. We subject our prescription to several checks: Kubo-Martin-Schwinger identities, the largest time equation, and the zero-temperature limit. When specializing to a particular retarded (causal) 3-point function, we find a very simple answer: the momentum-space correlator is given by three causal (two advanced and one retarded) bulk-to-boundary propagators, meeting at a vertex point which is integrated from spatial infinity to the horizon only. This result is expected based on analyticity, since the retarded n-point functions are obtained by analytic continuation from the imaginary-time Green's function, and based on causality considerations.

  2. Clustering and correlates of screen-time and eating behaviours among young adolescents

    Directory of Open Access Journals (Sweden)

    Natalie Pearson

    2017-05-01

    Full Text Available Abstract Background Screen-time and eating behaviours are associated in adolescents, but few studies have examined the clustering of these health behaviours in this age group. The identification of clustered health behaviours, and influences on adolescents’ clustered health behaviours, at the time when they are most likely to become habitual, is important for intervention design. The purpose of this study was to assess the prevalence and clustering of health behaviours in adolescents, and examine the sociodemographic, individual, behavioural, and home social and physical environmental correlates of clustered health behaviours. Methods Adolescents aged 11–12 years (n = 527, 48% boys completed a questionnaire during class-time which assessed screen-time (ST, fruit and vegetable (FV, and energy-dense (ED snack consumption using a Food Frequency Questionnaire. Health behaviours were categorised into high and low frequencies based on recommendations for FV and ST and median splits for ED snacks. Adolescents reported on their habits, self-efficacy, eating at the television (TV, eating and watching TV together with parents, restrictive parenting practices, and the availability and accessibility of foods within the home. Behavioural clustering was assessed using an observed over expected ratio (O/E. Correlates of clustered behaviours were examined using multivariate multinomial logistic regression. Results Approximately 70% reported having two or three health risk behaviours. Overall, O/E ratios were close to 1, which indicates clustering. The three risk behaviour combination of low FV, high ED, and high ST occurred more frequently than expected (O/E ratio = 1.06 95% CI 1.01, 1.15. Individual, behavioural, and social and physical home environmental correlates were differentially associated with behavioural clusters. Correlates consistently associated with clusters included eating ED snacks while watching TV, eating at the TV with parents, and

  3. Clustering and correlates of screen-time and eating behaviours among young adolescents.

    Science.gov (United States)

    Pearson, Natalie; Griffiths, Paula; Biddle, Stuart Jh; Johnston, Julie P; McGeorge, Sonia; Haycraft, Emma

    2017-05-31

    Screen-time and eating behaviours are associated in adolescents, but few studies have examined the clustering of these health behaviours in this age group. The identification of clustered health behaviours, and influences on adolescents' clustered health behaviours, at the time when they are most likely to become habitual, is important for intervention design. The purpose of this study was to assess the prevalence and clustering of health behaviours in adolescents, and examine the sociodemographic, individual, behavioural, and home social and physical environmental correlates of clustered health behaviours. Adolescents aged 11-12 years (n = 527, 48% boys) completed a questionnaire during class-time which assessed screen-time (ST), fruit and vegetable (FV), and energy-dense (ED) snack consumption using a Food Frequency Questionnaire. Health behaviours were categorised into high and low frequencies based on recommendations for FV and ST and median splits for ED snacks. Adolescents reported on their habits, self-efficacy, eating at the television (TV), eating and watching TV together with parents, restrictive parenting practices, and the availability and accessibility of foods within the home. Behavioural clustering was assessed using an observed over expected ratio (O/E). Correlates of clustered behaviours were examined using multivariate multinomial logistic regression. Approximately 70% reported having two or three health risk behaviours. Overall, O/E ratios were close to 1, which indicates clustering. The three risk behaviour combination of low FV, high ED, and high ST occurred more frequently than expected (O/E ratio = 1.06 95% CI 1.01, 1.15. Individual, behavioural, and social and physical home environmental correlates were differentially associated with behavioural clusters. Correlates consistently associated with clusters included eating ED snacks while watching TV, eating at the TV with parents, and the availability and accessibility of ED snack foods

  4. [Correlation factors of 127 times pre-crisis state in patients with myasthenia gravis].

    Science.gov (United States)

    Ou, C Y; Ran, H; Qiu, L; Huang, Z D; Lin, Z Z; Deng, J; Liu, W B

    2017-10-10

    Objective: To investigate the clinical features of the Pre-Crisis State and analyze the correlated risk factors of Pre-Crisis State of myasthenia crisis. Methods: We included 93 patients with myasthenia gravis (MG) who experienced 127 times Pre-Crisis State between October 2007 and July 2016. Those patients were hospitalized in the MG specialize center, Department of Neurological Science, first Affiliated Hospital of Sun Yat-sen University. The information of the general situation, the clinical manifestations and the blood gas analysis in those patients were collected using our innovated clinical research form. Statistic methods were applied including descriptive analysis, univariate logistic analysis, multivariate correlation logistic analysis, etc. Results: (1)The typical features of MG Pre-Crisis State included: dyspnea (127 times, 100% not requiring intubation or non-invasive ventilation), bulbar-muscle weakness (121 times, 95.28%), the increased blood partial pressure of carbon dioxide (PCO(2)) (94 times, 85.45%), expectoration weakness (99 times, 77.95%), sleep disorders (107 times, 84.25%) and the infection (99 times, 77.95%). The occurrence of dyspnea in combination with bulbar-muscle weakness ( P =0.002) or the increased blood PCO(2) ( P =0.042) often indicated the tendency of crisis. (2) The MG symptoms which were proportion to the occurrence of crisis includes: bulbar-muscle weakness ( P =0.028), fever ( P =0.028), malnutrition ( P =0.066), complications ( P =0.071), excess oropharyngeal secretions ( P =0.005) and the increased blood PCO(2) ( P =0.007). The perioperative period of thymectomy would not increase the risk of crisis. Conclusions: Dyspnea indicates the occurrence of the Pre-Crisis State of MG. In order to significantly reduce the morbidity of myasthenia crisis, the bulbar-muscle weakness, the increased blood PCO(2), expectoration weakness, sleep disorders, infection & fever and excess oropharyngeal secretions should be treated timely.

  5. Velocity landscape correlation resolves multiple flowing protein populations from fluorescence image time series.

    Science.gov (United States)

    Pandžić, Elvis; Abu-Arish, Asmahan; Whan, Renee M; Hanrahan, John W; Wiseman, Paul W

    2018-02-16

    Molecular, vesicular and organellar flows are of fundamental importance for the delivery of nutrients and essential components used in cellular functions such as motility and division. With recent advances in fluorescence/super-resolution microscopy modalities we can resolve the movements of these objects at higher spatio-temporal resolutions and with better sensitivity. Previously, spatio-temporal image correlation spectroscopy has been applied to map molecular flows by correlation analysis of fluorescence fluctuations in image series. However, an underlying assumption of this approach is that the sampled time windows contain one dominant flowing component. Although this was true for most of the cases analyzed earlier, in some situations two or more different flowing populations can be present in the same spatio-temporal window. We introduce an approach, termed velocity landscape correlation (VLC), which detects and extracts multiple flow components present in a sampled image region via an extension of the correlation analysis of fluorescence intensity fluctuations. First we demonstrate theoretically how this approach works, test the performance of the method with a range of computer simulated image series with varying flow dynamics. Finally we apply VLC to study variable fluxing of STIM1 proteins on microtubules connected to the plasma membrane of Cystic Fibrosis Bronchial Epithelial (CFBE) cells. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Timing of first sex before marriage and its correlates: evidence from India.

    Science.gov (United States)

    Santhya, K G; Acharya, Rajib; Jejeebhoy, Shireen J; Ram, Usha

    2011-03-01

    While several studies have documented the extent of pre-marital sexual experience among young people in India, little work has been done to explore the factors that are correlated with the timing of pre-marital sexual initiation. This paper examines age at initiation of pre-marital sex, circumstances in which first sex was experienced, nature of first sexual experience and correlates of age at initiation of pre-marital sex. Life table estimates suggest that pre-marital sexual initiation occurred in adolescence for 1 in 20 young women and 1 in 10 young men. For the majority of these young people, their first sex was with an opposite-sex romantic partner. First sex, moreover, was unprotected for the majority and forced for sizeable proportion of young women. A number of individual, family-, peer- and community-level factors were correlated with age at first pre-marital sex. Moreover, considerable gender differences were apparent in the correlates of age at first pre-marital sex, with peer- and parent-level factors found more often to be significant for young women than men.

  7. A non linear analysis of human gait time series based on multifractal analysis and cross correlations

    International Nuclear Information System (INIS)

    Munoz-Diosdado, A

    2005-01-01

    We analyzed databases with gait time series of adults and persons with Parkinson, Huntington and amyotrophic lateral sclerosis (ALS) diseases. We obtained the staircase graphs of accumulated events that can be bounded by a straight line whose slope can be used to distinguish between gait time series from healthy and ill persons. The global Hurst exponent of these series do not show tendencies, we intend that this is because some gait time series have monofractal behavior and others have multifractal behavior so they cannot be characterized with a single Hurst exponent. We calculated the multifractal spectra, obtained the spectra width and found that the spectra of the healthy young persons are almost monofractal. The spectra of ill persons are wider than the spectra of healthy persons. In opposition to the interbeat time series where the pathology implies loss of multifractality, in the gait time series the multifractal behavior emerges with the pathology. Data were collected from healthy and ill subjects as they walked in a roughly circular path and they have sensors in both feet, so we have one time series for the left foot and other for the right foot. First, we analyzed these time series separately, and then we compared both results, with direct comparison and with a cross correlation analysis. We tried to find differences in both time series that can be used as indicators of equilibrium problems

  8. A non linear analysis of human gait time series based on multifractal analysis and cross correlations

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Diosdado, A [Department of Mathematics, Unidad Profesional Interdisciplinaria de Biotecnologia, Instituto Politecnico Nacional, Av. Acueducto s/n, 07340, Mexico City (Mexico)

    2005-01-01

    We analyzed databases with gait time series of adults and persons with Parkinson, Huntington and amyotrophic lateral sclerosis (ALS) diseases. We obtained the staircase graphs of accumulated events that can be bounded by a straight line whose slope can be used to distinguish between gait time series from healthy and ill persons. The global Hurst exponent of these series do not show tendencies, we intend that this is because some gait time series have monofractal behavior and others have multifractal behavior so they cannot be characterized with a single Hurst exponent. We calculated the multifractal spectra, obtained the spectra width and found that the spectra of the healthy young persons are almost monofractal. The spectra of ill persons are wider than the spectra of healthy persons. In opposition to the interbeat time series where the pathology implies loss of multifractality, in the gait time series the multifractal behavior emerges with the pathology. Data were collected from healthy and ill subjects as they walked in a roughly circular path and they have sensors in both feet, so we have one time series for the left foot and other for the right foot. First, we analyzed these time series separately, and then we compared both results, with direct comparison and with a cross correlation analysis. We tried to find differences in both time series that can be used as indicators of equilibrium problems.

  9. Rotating Wavepackets

    Science.gov (United States)

    Lekner, John

    2008-01-01

    Any free-particle wavepacket solution of Schrodinger's equation can be converted by differentiations to wavepackets rotating about the original direction of motion. The angular momentum component along the motion associated with this rotation is an integral multiple of [h-bar]. It is an "intrinsic" angular momentum: independent of origin and…

  10. Rotating dryer

    International Nuclear Information System (INIS)

    Noe, C.

    1984-01-01

    Products to dry are introduced inside a rotating tube placed in an oven, the cross section of the tube is an arc of spiral. During clockwise rotation of the tube products are maintained inside and mixed, during anticlockwise products are removed. Application is made to drying of radioactive wastes [fr

  11. Correlation between weekly working time and burnout syndrome among anesthesiologists of Maceió-AL.

    Science.gov (United States)

    Barbosa, Fabiano Timbó; Eloi, Raissa Jardelino; Santos, Luciano Menezes Dos; Leão, Bruna Acioly; Lima, Fernando José Camelo de; Sousa-Rodrigues, Célio Fernando de

    The current jobs are insufficient to determine the causative agent, as well as to identify characteristic high risk profiles for BS, leaving a clear need for more studies to this end. This study objective was to evaluate the correlation between weekly workload and BS dimensions. An observational, descriptive, cross-sectional study performed with 43 anesthesiologists from Maceió-AL, with the application of Maslach Burnout Inventory (MBI) forms. Pearson's correlation coefficient r was used for the three dimensions and a 95% confidence interval for the prevalence of burnout syndrome and high scores in all three dimensions. Among the studied physicians, 51.16% were male and the average age was 49.82±12.05 years. For physicians who have been diagnosed with BS through the MBI, the average weekly working time 69.27±22.39h. The high level of frequency in at least one of the three dimensions was found in 67.44% of physicians, with this percentage being considered diagnostic for burnout syndrome in this population. This study showed no correlation between the weekly working time and the BS dimensions in this population. Copyright © 2016 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

  12. Socio-demographic correlates of leisure time physical activity among Portuguese adults

    Directory of Open Access Journals (Sweden)

    Adilson Marques

    2015-05-01

    Full Text Available This study aimed to identify socio-demographic correlates of leisure time physical activity among Portuguese adults. Subjects aged 31-60 years (1,076 males, 1,383 females were categorized into two groups according to recommended physical activities ranging from ≥ 10 or < 10 MET.hours.week-1. Leisure time physical activity data was self-reported, including activities, duration of each session and frequency. Chi-square and logistic regression analyses were applied to the results. Among men, having a high socioeconomic status (OR = 1.89; 95%CI: 1.30-2.76; p = 0.001 was associated with attaining the recommended level of physical activity. For women, middle education levels were associated with physical activity (OR = 1.36; 95%CI: 1.01-1.85. Moreover, middle socioeconomic status (OR = 1.45; 95%CI: 0.80-1.91; p = 0.009 was also positively associated with meeting physical activities recommendations in the unadjusted analysis. Men and women had different patterns of socio-demographic correlates. An intervention designed to improve the levels of physical activity among Portuguese adults may take these correlates into account.

  13. Cycling in São Paulo, Brazil (1997–2012: Correlates, time trends and health consequences

    Directory of Open Access Journals (Sweden)

    Thiago Hérick Sá

    2016-12-01

    Full Text Available The purpose of the study was to describe cyclists and cycling trips, and to explore correlates, time trends and health consequences of cycling in São Paulo, Brazil from 1997 to 2012. Cross-sectional analysis using repeated São Paulo Household Travel Surveys (HTS. At all time periods cycling was a minority travel mode in São Paulo (1174 people with cycling trips out of 214,719 people. Poisson regressions for individual correlates were estimated using the entire 2012 HTS sample. Men were six times more likely to cycle than women. We found rates of bicycle use rising over time among the richest quartile but total cycling rates dropped from 1997 to 2012 due to decreasing rates among the poor. Harms from air pollution would negate benefits from physical activity through cycling only at 1997 air pollution levels and at very high cycling levels (≥9 h of cycling per day. Exposure-based road injury risk decreased between 2007 and 2012, from 0.76 to 0.56 cyclist deaths per 1000 person-hours travelled. Policies to reduce spatial segregation, measures to tackle air pollution, improvements in dedicated cycling infrastructure, and integrating the bicycle with the public transport system in neighborhoods of all income levels could make cycling safer and prevent more individuals from abandoning the cycling mode in São Paulo.

  14. Tracking of multiple objects with time-adjustable composite correlation filters

    Science.gov (United States)

    Ruchay, Alexey; Kober, Vitaly; Chernoskulov, Ilya

    2017-09-01

    An algorithm for tracking of multiple objects in video based on time-adjustable adaptive composite correlation filtering is proposed. For each frame a bank of composite correlation filters are designed in such a manner to provide invariance to pose, occlusion, clutter, and illumination changes. The filters are synthesized with the help of an iterative algorithm, which optimizes the discrimination capability for each object. The filters are adapted to the objects changes online using information from the current and past scene frames. Results obtained with the proposed algorithm using real-life scenes are presented and compared with those obtained with state-of-the-art tracking methods in terms of detection efficiency, tracking accuracy, and speed of processing.

  15. Quantum correlations in Newtonian space and time: arbitrarily fast communication or nonlocality

    Science.gov (United States)

    Gisin, Nicolas

    2013-03-01

    Experimental violations of Bell inequalities using space-like separated measurements precludes the explanation of quantum correlations through causal influences propagating at subluminal speed. Yet, ``everything looks as if the two parties somehow communicate behind the scene.'' We investigate the assumption that they do so at a speed faster than light, though finite. Such an assumption doesn't respect the spirit of Einstein relativity. However, it is not crystal clear that such ``communication behind the scene'' would contradict relativity. Indeed, one could imagine that this communication remains for ever hidden to humans, i.e. that it could not be controlled by humans, only Nature exploits it to produce correlations that can't be explained by usual common causes. To define faster than light hidden communication requires a universal privileged reference frame in which this faster than light speed is defined. Again, such a universal privileged frame is not in the spirit of relativity, but it is also clearly not in contradiction: for example the reference frame in which the cosmic microwave background radiation is isotropic defines such a privileged frame. Hence, a priori, a hidden communication explanation is not more surprising than nonlocality. We prove that for any finite speed, such models predict correlations that can be exploited for faster-than-light communication. This superluminal communication doesn't require access to any hidden physical quantities, but only the manipulation of measurement devices at the level of our present-day description of quantum experiments. Consequently, all possible explanations of quantum correlations that satisfy the principle of continuity, which states that everything propagates gradually and continuously through space and time, or in other words, all combination of local common causes and direct causes that reproduce quantum correlations, lead to faster than light communication. Accordingly, either there is superluminal

  16. Gyrochronology relating star age to rotational period is derived from first principles through a novel time dual for thermodynamics, named lingerdynamics

    Science.gov (United States)

    Feria, Erlan H.

    2017-10-01

    Gyrochronology estimates the age of a low-mass star from its rotational period, which is found from changes in brightness caused by dark star spots. First revealed as an insight in (Skumanich, A. 1972, The Astrophysical Journal. 171: 565) it allows astronomers to find true sun-like stars that may harbor life in its planets (Meibom, S. et. al., Nature. 517: 589-591). Here a simple expression for the age of a star is derived through a novel linger thermo theory (LTT) integrating thermodynamics with its revealed time-dual, named lingerdynamics. This expression relates the star age to the ratio of past and present rotational period metrics (RPM) of lingerdynamics. LTT has been used earlier to derive a simple expression for the finding of the entropy of spherical-homogeneous mediums (Feria, E. H. Nov. 19, 2016, Linger Thermo Theory, IEEE Int’l Conf. on Smart Cloud, 18 pages, DOI 10.1109/SmartCloud.2016.57, Colombia Univ., N.Y., N.Y. and Feria, E. H. June 7th 2017, AAS 340th Meeting). In LTT the lifespan of system operation τ is given by: τ = (2Π /3v3)G2M2 x RPM where G is the gravitational constant, Π is the pace of mass-energy retention in s/m3 units (e.g., for our current sun it is given by 5 billion ‘future’ years over its volume), and v is the perpetual radial speed about the point-mass M. Since in LTT a star is modeled as a point mass at the center of its spherical volume, its RPM is not the same as the measured rotational period of an actual star. For instance, for our sun its equator rotational period is approximately 25.34 days, while in lingerdynamics it is a fraction of a day, i.e., 0.116 days, where this value is derived from the RPM expression 2πrsun/(GMsun / rsun)1/2 where 2πrsun is the circumference of the sun, (GMsun/rsun)1/2 is the perpetual radial speed v for our point-mass modeled sun, and rsun and Msun are the sun radius and point-mass, respectively. However, using conservation of angular momentum arguments it is assumed that the ratio of

  17. Dynamic Hebbian Cross-Correlation Learning Resolves the Spike Timing Dependent Plasticity Conundrum

    Directory of Open Access Journals (Sweden)

    Tjeerd V. olde Scheper

    2018-01-01

    Full Text Available Spike Timing-Dependent Plasticity has been found to assume many different forms. The classic STDP curve, with one potentiating and one depressing window, is only one of many possible curves that describe synaptic learning using the STDP mechanism. It has been shown experimentally that STDP curves may contain multiple LTP and LTD windows of variable width, and even inverted windows. The underlying STDP mechanism that is capable of producing such an extensive, and apparently incompatible, range of learning curves is still under investigation. In this paper, it is shown that STDP originates from a combination of two dynamic Hebbian cross-correlations of local activity at the synapse. The correlation of the presynaptic activity with the local postsynaptic activity is a robust and reliable indicator of the discrepancy between the presynaptic neuron and the postsynaptic neuron's activity. The second correlation is between the local postsynaptic activity with dendritic activity which is a good indicator of matching local synaptic and dendritic activity. We show that this simple time-independent learning rule can give rise to many forms of the STDP learning curve. The rule regulates synaptic strength without the need for spike matching or other supervisory learning mechanisms. Local differences in dendritic activity at the synapse greatly affect the cross-correlation difference which determines the relative contributions of different neural activity sources. Dendritic activity due to nearby synapses, action potentials, both forward and back-propagating, as well as inhibitory synapses will dynamically modify the local activity at the synapse, and the resulting STDP learning rule. The dynamic Hebbian learning rule ensures furthermore, that the resulting synaptic strength is dynamically stable, and that interactions between synapses do not result in local instabilities. The rule clearly demonstrates that synapses function as independent localized

  18. The rotating universe

    International Nuclear Information System (INIS)

    Ruben, G.; Treder, H.J.

    1987-01-01

    For a long time the question whether the universe rotates or not is discussed. Aspects of Huygens, Newton, Mach and other important historical scientists in this field are reported. The investigations of the mathematician Kurt Groedel in order to prove the rotation of the universe are illustrated. Kurt Groedel has shown that Einstein's gravitational equations of general relativity theory and the cosmological postulate of global homogeneity of cosmic matter (that is the Copernical principle) are not contradictionary to a rotating universe. Abberation measurements, position determination by means of radiointerferometry and methods for the determination of the rotation of the universe from the isotropy of the background radiation are presented. From these experiments it can be concluded that the universe seems not to rotate as already Einstein expected

  19. A study of pile-up in integrated time-correlated single photon counting systems.

    Science.gov (United States)

    Arlt, Jochen; Tyndall, David; Rae, Bruce R; Li, David D-U; Richardson, Justin A; Henderson, Robert K

    2013-10-01

    Recent demonstration of highly integrated, solid-state, time-correlated single photon counting (TCSPC) systems in CMOS technology is set to provide significant increases in performance over existing bulky, expensive hardware. Arrays of single photon single photon avalanche diode (SPAD) detectors, timing channels, and signal processing can be integrated on a single silicon chip with a degree of parallelism and computational speed that is unattainable by discrete photomultiplier tube and photon counting card solutions. New multi-channel, multi-detector TCSPC sensor architectures with greatly enhanced throughput due to minimal detector transit (dead) time or timing channel dead time are now feasible. In this paper, we study the potential for future integrated, solid-state TCSPC sensors to exceed the photon pile-up limit through analytic formula and simulation. The results are validated using a 10% fill factor SPAD array and an 8-channel, 52 ps resolution time-to-digital conversion architecture with embedded lifetime estimation. It is demonstrated that pile-up insensitive acquisition is attainable at greater than 10 times the pulse repetition rate providing over 60 dB of extended dynamic range to the TCSPC technique. Our results predict future CMOS TCSPC sensors capable of live-cell transient observations in confocal scanning microscopy, improved resolution of near-infrared optical tomography systems, and fluorescence lifetime activated cell sorting.

  20. Developmental patterns and parental correlates of youth leisure-time physical activity.

    Science.gov (United States)

    Lam, Chun Bun; McHale, Susan M

    2015-02-01

    This study examined the developmental patterns and parental correlates of youth leisure-time physical activity from middle childhood through adolescence. On 5 occasions across 7 years, fathers, mothers, and children who were first- and second born from 201 European American, working- and middle-class families participated in home and multiple nightly phone interviews. Multilevel modeling revealed that, controlling for family socioeconomic status, neighborhood characteristics, and youth overweight status and physical health, leisure-time physical activity increased during middle childhood and declined across adolescence, and the decline was more pronounced for girls than for boys. Moreover, controlling for time-varying, parental work hours and youth interest in sports and outdoor activities, on occasions when fathers and mothers spent proportionally more time on these activities with youth than usual, youth also spent more total time on these activities than usual. The within-person association between mother-youth joint involvement and youth's total involvement in leisure-time physical activity reached statistical significance at the transition to adolescence, and became stronger over time. Findings highlight the importance of maintaining adolescents', especially girls', physical activity levels and targeting both fathers' and mothers' involvement to promote youth's physical activity. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  1. Urban Link Travel Time Prediction Based on a Gradient Boosting Method Considering Spatiotemporal Correlations

    Directory of Open Access Journals (Sweden)

    Faming Zhang

    2016-11-01

    Full Text Available The prediction of travel times is challenging because of the sparseness of real-time traffic data and the intrinsic uncertainty of travel on congested urban road networks. We propose a new gradient–boosted regression tree method to accurately predict travel times. This model accounts for spatiotemporal correlations extracted from historical and real-time traffic data for adjacent and target links. This method can deliver high prediction accuracy by combining simple regression trees with poor performance. It corrects the error found in existing models for improved prediction accuracy. Our spatiotemporal gradient–boosted regression tree model was verified in experiments. The training data were obtained from big data reflecting historic traffic conditions collected by probe vehicles in Wuhan from January to May 2014. Real-time data were extracted from 11 weeks of GPS records collected in Wuhan from 5 May 2014 to 20 July 2014. Based on these data, we predicted link travel time for the period from 21 July 2014 to 25 July 2014. Experiments showed that our proposed spatiotemporal gradient–boosted regression tree model obtained better results than gradient boosting, random forest, or autoregressive integrated moving average approaches. Furthermore, these results indicate the advantages of our model for urban link travel time prediction.

  2. Time and spectrum-resolving multiphoton correlator for 300–900 nm

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Kelsey D.; Thibault, Marilyne; Jennewein, Thomas [Institute for Quantum Computing and Department for Physics and Astronomy, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1 (Canada); Kolenderski, Piotr, E-mail: kolenderski@fizyka.umk.pl [Institute for Quantum Computing and Department for Physics and Astronomy, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1 (Canada); Faculty of Physics, Astronomy and Informatics, Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Scarcella, Carmelo; Tosi, Alberto [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy)

    2014-10-14

    We demonstrate a single-photon sensitive spectrometer in the visible range, which allows us to perform time-resolved and multi-photon spectral correlation measurements at room temperature. It is based on a monochromator composed of two gratings, collimation optics, and an array of single photon avalanche diodes. The time resolution can reach 110 ps and the spectral resolution is 2 nm/pixel, limited by the design of the monochromator. This technique can easily be combined with commercial monochromators and can be useful for joint spectrum measurements of two photons emitted in the process of parametric down conversion, as well as time-resolved spectrum measurements in optical coherence tomography or medical physics applications.

  3. Foundations for a time reliability correlation system to quantify human reliability

    International Nuclear Information System (INIS)

    Dougherty, E.M. Jr.; Fragola, J.R.

    1988-01-01

    Time reliability correlations (TRCs) have been used in human reliability analysis (HRA) in conjunction with probabilistic risk assessment (PRA) to quantify post-initiator human failure events. The first TRCs were judgmental but recent data taken from simulators have provided evidence for development of a system of TRCs. This system has the equational form: t = tau R X tau U , where the first factor is the lognormally distributed random variable of successful response time, derived from the simulator data, and the second factor is a unitary lognormal random variable to account for uncertainty in the model. The first random variable is further factored into a median response time and a factor to account for the dominant type of behavior assumed to be involved in the response and a second factor to account for other influences on the reliability of the response

  4. Time-Shift Correlation Algorithm for P300 Event Related Potential Brain-Computer Interface Implementation

    Directory of Open Access Journals (Sweden)

    Ju-Chi Liu

    2016-01-01

    Full Text Available A high efficient time-shift correlation algorithm was proposed to deal with the peak time uncertainty of P300 evoked potential for a P300-based brain-computer interface (BCI. The time-shift correlation series data were collected as the input nodes of an artificial neural network (ANN, and the classification of four LED visual stimuli was selected as the output node. Two operating modes, including fast-recognition mode (FM and accuracy-recognition mode (AM, were realized. The proposed BCI system was implemented on an embedded system for commanding an adult-size humanoid robot to evaluate the performance from investigating the ground truth trajectories of the humanoid robot. When the humanoid robot walked in a spacious area, the FM was used to control the robot with a higher information transfer rate (ITR. When the robot walked in a crowded area, the AM was used for high accuracy of recognition to reduce the risk of collision. The experimental results showed that, in 100 trials, the accuracy rate of FM was 87.8% and the average ITR was 52.73 bits/min. In addition, the accuracy rate was improved to 92% for the AM, and the average ITR decreased to 31.27 bits/min. due to strict recognition constraints.

  5. Time-Shift Correlation Algorithm for P300 Event Related Potential Brain-Computer Interface Implementation.

    Science.gov (United States)

    Liu, Ju-Chi; Chou, Hung-Chyun; Chen, Chien-Hsiu; Lin, Yi-Tseng; Kuo, Chung-Hsien

    2016-01-01

    A high efficient time-shift correlation algorithm was proposed to deal with the peak time uncertainty of P300 evoked potential for a P300-based brain-computer interface (BCI). The time-shift correlation series data were collected as the input nodes of an artificial neural network (ANN), and the classification of four LED visual stimuli was selected as the output node. Two operating modes, including fast-recognition mode (FM) and accuracy-recognition mode (AM), were realized. The proposed BCI system was implemented on an embedded system for commanding an adult-size humanoid robot to evaluate the performance from investigating the ground truth trajectories of the humanoid robot. When the humanoid robot walked in a spacious area, the FM was used to control the robot with a higher information transfer rate (ITR). When the robot walked in a crowded area, the AM was used for high accuracy of recognition to reduce the risk of collision. The experimental results showed that, in 100 trials, the accuracy rate of FM was 87.8% and the average ITR was 52.73 bits/min. In addition, the accuracy rate was improved to 92% for the AM, and the average ITR decreased to 31.27 bits/min. due to strict recognition constraints.

  6. On a Correlation between the Ionospheric Electric Field and the Time Derivative of the Magnetic Field

    Directory of Open Access Journals (Sweden)

    R. R. Ilma

    2012-01-01

    Full Text Available A correlation of the ionospheric electric field and the time derivative of the magnetic field was noticed over thirty years ago and has yet to be explained. Here we report on another set of examples during the superstorm of November 2004. The electric field in the equatorial ionosphere, measured with the Jicamarca incoherent scatter radar, exhibited a 3 mV/m electric field pulse that was not seen in the interplanetary medium. It was, however, accompanied by a correlation with the time derivative of the magnetic field measured at two points in Peru. Our inclination was to assume that the field was inductive. However, the time scale of the pulse was too short for the magnetic field to penetrate the crust of the Earth. This means that the area threaded by ∂B/∂t was too small to create the observed electric field by induction. We suggest that the effect was caused by a modulation of the ring current location relative to the Earth due to the electric field. This electric field is required, as the magnetic field lines are considered frozen into the plasma in the magnetosphere. The closer location of the ring current to the Earth in turn increased the magnetic field at the surface.

  7. Combined use of correlation dimension and entropy as discriminating measures for time series analysis

    Science.gov (United States)

    Harikrishnan, K. P.; Misra, R.; Ambika, G.

    2009-09-01

    We show that the combined use of correlation dimension (D2) and correlation entropy (K2) as discriminating measures can extract a more accurate information regarding the different types of noise present in a time series data. For this, we make use of an algorithmic approach for computing D2 and K2 proposed by us recently [Harikrishnan KP, Misra R, Ambika G, Kembhavi AK. Physica D 2006;215:137; Harikrishnan KP, Ambika G, Misra R. Mod Phys Lett B 2007;21:129; Harikrishnan KP, Misra R, Ambika G. Pramana - J Phys, in press], which is a modification of the standard Grassberger-Proccacia scheme. While the presence of white noise can be easily identified by computing D2 of data and surrogates, K2 is a better discriminating measure to detect colored noise in the data. Analysis of time series from a real world system involving both white and colored noise is presented as evidence. To our knowledge, this is the first time that such a combined analysis is undertaken on a real world data.

  8. Record statistics of a strongly correlated time series: random walks and Lévy flights

    Science.gov (United States)

    Godrèche, Claude; Majumdar, Satya N.; Schehr, Grégory

    2017-08-01

    We review recent advances on the record statistics of strongly correlated time series, whose entries denote the positions of a random walk or a Lévy flight on a line. After a brief survey of the theory of records for independent and identically distributed random variables, we focus on random walks. During the last few years, it was indeed realized that random walks are a very useful ‘laboratory’ to test the effects of correlations on the record statistics. We start with the simple one-dimensional random walk with symmetric jumps (both continuous and discrete) and discuss in detail the statistics of the number of records, as well as of the ages of the records, i.e. the lapses of time between two successive record breaking events. Then we review the results that were obtained for a wide variety of random walk models, including random walks with a linear drift, continuous time random walks, constrained random walks (like the random walk bridge) and the case of multiple independent random walkers. Finally, we discuss further observables related to records, like the record increments, as well as some questions raised by physical applications of record statistics, like the effects of measurement error and noise.

  9. Uranium mass and neutron multiplication factor estimates from time-correlation coincidence counts

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wenxiong [China Academy of Engineering Physics, Center for Strategic Studies, Beijing 100088 (China); Li, Jiansheng [China Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang 621900 (China); Zhu, Jianyu [China Academy of Engineering Physics, Center for Strategic Studies, Beijing 100088 (China)

    2015-10-11

    Time-correlation coincidence counts of neutrons are an important means to measure attributes of nuclear material. The main deficiency in the analysis is that an attribute of an unknown component can only be assessed by comparing it with similar known components. There is a lack of a universal method of measurement suitable for the different attributes of the components. This paper presents a new method that uses universal relations to estimate the mass and neutron multiplication factor of any uranium component with known enrichment. Based on numerical simulations and analyses of 64 highly enriched uranium components with different thicknesses and average radii, the relations between mass, multiplication and coincidence spectral features have been obtained by linear regression analysis. To examine the validity of the method in estimating the mass of uranium components with different sizes, shapes, enrichment, and shielding, the features of time-correlation coincidence-count spectra for other objects with similar attributes are simulated. Most of the masses and multiplications for these objects could also be derived by the formulation. Experimental measurements of highly enriched uranium castings have also been used to verify the formulation. The results show that for a well-designed time-dependent coincidence-count measuring system of a uranium attribute, there are a set of relations dependent on the uranium enrichment by which the mass and multiplication of the measured uranium components of any shape and size can be estimated from the features of the source-detector coincidence-count spectrum.

  10. Clinical correlation to differences in ranibizumab and aflibercept vascular endothelial growth factor suppression times.

    Science.gov (United States)

    Fauser, Sascha; Muether, Philipp S

    2016-11-01

    To determine clinical correlations to intraocular vascular endothelial growth factor A (VEGF-A) suppression times (VSTs) on the treatment of neovascular age-related macular degeneration (nAMD) with ranibizumab (Lucentis) or aflibercept (Eylea). Seven of 89 treatment-naïve nAMD eyes showed persistent choroidal neovascular membrane (CNV) activity throughout a spectral domain optical coherence tomography (SD-OCT)-driven pro re nata (PRN) regimen of intravitreal ranibizumab injections over 28±4 months. The treatment was switched to PRN aflibercept injections and patients were followed for another 15±2 months. A total of 160 aqueous humour specimens were collected before the intravitreal injections, and their VEGF-A concentrations were assayed by Luminex multiplex bead analysis (Luminex, Austin, Texas, USA). Intraocular VEGF-A concentrations were correlated to CNV activity shown by SD-OCT. The mean duration of suppression of VEGF-A concentrations in aqueous humour below the lower limit of quantification of our assay was 34±5 (26-69) days for ranibizumab and 67±14 (49-89) days for aflibercept (p<0.001). The percentual reduction of central retinal volume (CRV) 6 weeks after injection was higher for aflibercept compared with ranibizumab (p=0.009). The time point of clinical re-activity occurred about 50% earlier than the respective VST for each ranibizumab and aflibercept. The VST under aflibercept treatment exceeded that under ranibizumab treatment by a factor of 2. This difference correlated with differential clinical CRV reduction 6 weeks after the respective injection. For both medications, clinical activity was found at a time point as early as 50% of the individual VST. NCT01213667, post-results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  11. The correlates of leisure time physical activity among an adults population from southern Taiwan.

    Science.gov (United States)

    Chen, Yi-Ju; Huang, Ying-Hsiang; Lu, Feng-Hwa; Wu, Jin-Shang; Lin, Linda L; Chang, Chih-Jen; Yang, Yi-Ching

    2011-06-03

    Assessing the correlates of practicing physical activity during leisure time is important with regard to planning and designing public health strategies to increase beneficial behaviors among adult populations. Although the importance of leisure time physical activity (LTPA) is highlighted in many Western countries, there are not many publications on physical activity patterns, and even less on their correlates, in non-Western societies. The goal of this study was thus to explore the determinants influencing adults' leisure time physical activity (LTPA) in a city in southern Taiwan. A cross-sectional population-based study was conducted in 2007, using a standardized questionnaire. Energy expenditure was dichotomized into two groups based on the recommended levels of moderate physical activity from LTPA: ≥10 or benefits of exercise (OR = 1.85;95%CI = 1.25-2.74), more sports media consumption (OR = 1.94;95%CI = 1.26-2.98), and higher self-efficacy (OR = 3.99;95%CI = 2.67-5.97) were more likely to engage in LTPA. Further analysis comparing different sources of social support showed only social support from friends had a significant positive association (OR = 1.73;95%CI = 1.14-2.63) with increased LTPA. LTPA in southern city of Taiwan showed some unique associations with age, socioeconomic status and media consumption that are not commonly reported in the Western World and similar associations with regards to psychosocial correlates of LTPA participation. Further studies from developing countries are warranted to highlight culture-specific differences in physical activity participation.

  12. Correlated electron dynamics and memory in time-dependent density functional theory

    International Nuclear Information System (INIS)

    Thiele, Mark

    2009-01-01

    Time-dependent density functional theory (TDDFT) is an exact reformulation of the time-dependent many-electron Schroedinger equation, where the problem of many interacting electrons is mapped onto the Kohn-Sham system of noninteracting particles which reproduces the exact electronic density. In the Kohn-Sham system all non-classical many-body effects are incorporated in the exchange-correlation potential which is in general unknown and needs to be approximated. It is the goal of this thesis to investigate the connection between memory effects and correlated electron dynamics in strong and weak fields. To this end one-dimensional two-electron singlet systems are studied. At the same time these systems include the onedimensional helium atom model, which is an established system to investigate the crucial effects of correlated electron dynamics in external fields. The studies presented in this thesis show that memory effects are negligible for typical strong field processes. Here the approximation of the spatial nonlocality is of primary importance. For the photoabsorption spectra on the other hand the neglect of memory effects leads to qualitative and quantitative errors, which are shown to be connected to transitions of double excitation character. To develop a better understanding of the conditions under which memory effects become important quantum fluid dynamics has been found to be especially suitable. It represents a further exact reformulation of the quantum mechanic many-body problem which is based on hydrodynamic quantities such as density and velocity. Memory effects are shown to be important whenever the velocity field develops strong gradients and dissipative effects contribute. (orig.)

  13. Correlated electron dynamics and memory in time-dependent density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Thiele, Mark

    2009-07-28

    Time-dependent density functional theory (TDDFT) is an exact reformulation of the time-dependent many-electron Schroedinger equation, where the problem of many interacting electrons is mapped onto the Kohn-Sham system of noninteracting particles which reproduces the exact electronic density. In the Kohn-Sham system all non-classical many-body effects are incorporated in the exchange-correlation potential which is in general unknown and needs to be approximated. It is the goal of this thesis to investigate the connection between memory effects and correlated electron dynamics in strong and weak fields. To this end one-dimensional two-electron singlet systems are studied. At the same time these systems include the onedimensional helium atom model, which is an established system to investigate the crucial effects of correlated electron dynamics in external fields. The studies presented in this thesis show that memory effects are negligible for typical strong field processes. Here the approximation of the spatial nonlocality is of primary importance. For the photoabsorption spectra on the other hand the neglect of memory effects leads to qualitative and quantitative errors, which are shown to be connected to transitions of double excitation character. To develop a better understanding of the conditions under which memory effects become important quantum fluid dynamics has been found to be especially suitable. It represents a further exact reformulation of the quantum mechanic many-body problem which is based on hydrodynamic quantities such as density and velocity. Memory effects are shown to be important whenever the velocity field develops strong gradients and dissipative effects contribute. (orig.)

  14. Effects of reagent rotational excitation on the H + CHD3 → H2 + CD3 reaction: A seven dimensional time-dependent wave packet study

    International Nuclear Information System (INIS)

    Zhang, Zhaojun; Zhang, Dong H.

    2014-01-01

    Seven-dimensional time-dependent wave packet calculations have been carried out for the title reaction to obtain reaction probabilities and cross sections for CHD 3 in J 0 = 1, 2 rotationally excited initial states with k 0 = 0 − J 0 (the projection of CHD 3 rotational angular momentum on its C 3 axis). Under the centrifugal sudden (CS) approximation, the initial states with the projection of the total angular momentum on the body fixed axis (K 0 ) equal to k 0 are found to be much more reactive, indicating strong dependence of reactivity on the orientation of the reagent CHD 3 with respect to the relative velocity between the reagents H and CHD 3 . However, at the coupled-channel (CC) level this dependence becomes much weak although in general the K 0 specified cross sections for the K 0 = k 0 initial states remain primary to the overall cross sections, implying the Coriolis coupling is important to the dynamics of the reaction. The calculated CS and CC integral cross sections obtained after K 0 averaging for the J 0 = 1, 2 initial states with all different k 0 are essentially identical to the corresponding CS and CC results for the J 0 = 0 initial state, meaning that the initial rotational excitation of CHD 3 up to J 0 = 2, regardless of its initial k 0 , does not have any effect on the total cross sections for the title reaction, and the errors introduced by the CS approximation on integral cross sections for the rotationally excited J 0 = 1, 2 initial states are the same as those for the J 0 = 0 initial state

  15. Factors influencing first-time fathers' involvement in their wives' pregnancy and childbirth: A correlational study.

    Science.gov (United States)

    Xue, Weilin Lynn; He, Hong-Gu; Chua, Ying Jie; Wang, Wenru; Shorey, Shefaly

    2018-03-20

    To examine factors influencing first-time fathers' involvement in their wives' pregnancy and childbirth in Singapore. A cross-sectional descriptive correlational study was conducted in a public tertiary hospital in Singapore. A total of 182 first-time fathers whose wives were hospitalized at four obstetric wards were recruited from November 2015 to January 2016. Data were collected by three newly developed and validated instruments, namely Father's Involvement in Pregnancy and Childbirth, Father's Informational and Sources of Support, and Father's Attitude Towards Involvement in Pregnancy and Childbirth, as well as the 16-item Couple Satisfaction Index and Family of Origin Questionnaire. The participants were generally involved in their wives' pregnancy and childbirth, with 35.2% being highly involved. There was no significant difference in fathers' levels of involvement between or among any sociodemographic subgroups. Significant Spearman's correlations were found between fathers' levels of involvement and levels of informational support as well as fathers' attitudes towards involvement. However, the logistic regression showed the level of informational support was the only significant factor that influenced first-time fathers' high levels of involvement in their wives' pregnancy and childbirth. The study revealed the importance of providing sufficient informational support to first-time fathers so that they can be highly involved in their wife's pregnancy and childbirth. Future studies can develop technology-based intervention programmes to improve fathers' involvement in their wife's pregnancy and childbirth. Healthcare professionals should examine and improve the existing informational support for first-time fathers and ensure its relevance and convenient access. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Is there a correlation between intravaginal ejaculatory latency time and enuresis? An exploratory study.

    Science.gov (United States)

    Koyuncu, Hakan; Serefoglu, Ege Can; Karacay, Safak; Ozdemir, Ahmet Tunc; Kalkan, Mehmet; Yencilek, Faruk

    2014-01-01

    Premature ejaculation (PE) is the most common male sexual dysfunction. Monosymptomatic enuresis (ME) is nocturnal bed wetting, without any daytime symptoms. Recent clinical studies report an association between lifelong PE and ME. The purpose of this study was to compare the intravaginal ejaculatory time (IELT) between lifelong PE in men with and without ME. The goal was to determine if there is an association between the severity of ME and of IELT. A total of 137 men with lifelong PE were included in this study. Subjects were asked if they had childhood ME. The characteristics and mean IELTs of patients with and without ME were compared using the student's t-test, and the correlation between severity of ME and IELT was assessed with trend test. Of the 137 lifelong PE patients, 57 reported ME. There was a strong negative correlation in patients with ME between the severity of enuresis and IELT, with IELT being shorter in patients with severe ME. A strong correlation between IELT and the severity of ME suggests a common underlying mechanism. Further studies are required to confirm these findings and elucidate the exact pathophysiology.

  17. Correlates of sedentary time in different age groups: results from a large cross sectional Dutch survey.

    Science.gov (United States)

    Bernaards, Claire M; Hildebrandt, Vincent H; Hendriksen, Ingrid J M

    2016-10-26

    Evidence shows that prolonged sitting is associated with an increased risk of mortality, independent of physical activity (PA). The aim of the study was to identify correlates of sedentary time (ST) in different age groups and day types (i.e. school-/work day versus non-school-/non-work day). The study sample consisted of 1895 Dutch children (4-11 years), 1131 adolescents (12-17 years), 8003 adults (18-64 years) and 1569 elderly (65 years and older) who enrolled in the Dutch continuous national survey 'Injuries and Physical Activity in the Netherlands' between 2006 and 2011. Respondents estimated the number of sitting hours during a regular school-/workday and a regular non-school/non-work day. Multiple linear regression analyses on cross-sectional data were used to identify correlates of ST. Significant positive associations with ST were observed for: higher age (4-to-17-year-olds and elderly), male gender (adults), overweight (children), higher education (adults ≥ 30 years), urban environment (adults), chronic disease (adults ≥ 30 years), sedentary work (adults), not meeting the moderate to vigorous PA (MVPA) guideline (children and adults ≥ 30 years) and not meeting the vigorous PA (VPA) guideline (4-to-17-year-olds). Correlates of ST that significantly differed between day types were working hours and meeting the VPA guideline. More working hours were associated with more ST on school-/work days. In children and adolescents, meeting the VPA guideline was associated with less ST on non-school/non-working days only. This study provides new insights in the correlates of ST in different age groups and thus possibilities for interventions in these groups. Correlates of ST appear to differ between age groups and to a lesser degree between day types. This implies that interventions to reduce ST should be age specific. Longitudinal studies are needed to draw conclusions on causality of the relationship between identified correlates and ST.

  18. Correlates of sedentary time in different age groups: results from a large cross sectional Dutch survey

    Directory of Open Access Journals (Sweden)

    Claire M. Bernaards

    2016-10-01

    Full Text Available Abstract Background Evidence shows that prolonged sitting is associated with an increased risk of mortality, independent of physical activity (PA. The aim of the study was to identify correlates of sedentary time (ST in different age groups and day types (i.e. school-/work day versus non-school-/non-work day. Methods The study sample consisted of 1895 Dutch children (4–11 years, 1131 adolescents (12–17 years, 8003 adults (18–64 years and 1569 elderly (65 years and older who enrolled in the Dutch continuous national survey ‘Injuries and Physical Activity in the Netherlands’ between 2006 and 2011. Respondents estimated the number of sitting hours during a regular school-/workday and a regular non-school/non-work day. Multiple linear regression analyses on cross-sectional data were used to identify correlates of ST. Results Significant positive associations with ST were observed for: higher age (4-to-17-year-olds and elderly, male gender (adults, overweight (children, higher education (adults ≥ 30 years, urban environment (adults, chronic disease (adults ≥ 30 years, sedentary work (adults, not meeting the moderate to vigorous PA (MVPA guideline (children and adults ≥ 30 years and not meeting the vigorous PA (VPA guideline (4-to-17-year-olds. Correlates of ST that significantly differed between day types were working hours and meeting the VPA guideline. More working hours were associated with more ST on school-/work days. In children and adolescents, meeting the VPA guideline was associated with less ST on non-school/non-working days only. Conclusions This study provides new insights in the correlates of ST in different age groups and thus possibilities for interventions in these groups. Correlates of ST appear to differ between age groups and to a lesser degree between day types. This implies that interventions to reduce ST should be age specific. Longitudinal studies are needed to draw conclusions on causality of

  19. Regression analysis of longitudinal data with correlated censoring and observation times.

    Science.gov (United States)

    Li, Yang; He, Xin; Wang, Haiying; Sun, Jianguo

    2016-07-01

    Longitudinal data occur in many fields such as the medical follow-up studies that involve repeated measurements. For their analysis, most existing approaches assume that the observation or follow-up times are independent of the response process either completely or given some covariates. In practice, it is apparent that this may not be true. In this paper, we present a joint analysis approach that allows the possible mutual correlations that can be characterized by time-dependent random effects. Estimating equations are developed for the parameter estimation and the resulted estimators are shown to be consistent and asymptotically normal. The finite sample performance of the proposed estimators is assessed through a simulation study and an illustrative example from a skin cancer study is provided.

  20. Post-event human decision errors: operator action tree/time reliability correlation

    Energy Technology Data Exchange (ETDEWEB)

    Hall, R E; Fragola, J; Wreathall, J

    1982-11-01

    This report documents an interim framework for the quantification of the probability of errors of decision on the part of nuclear power plant operators after the initiation of an accident. The framework can easily be incorporated into an event tree/fault tree analysis. The method presented consists of a structure called the operator action tree and a time reliability correlation which assumes the time available for making a decision to be the dominating factor in situations requiring cognitive human response. This limited approach decreases the magnitude and complexity of the decision modeling task. Specifically, in the past, some human performance models have attempted prediction by trying to emulate sequences of human actions, or by identifying and modeling the information processing approach applicable to the task. The model developed here is directed at describing the statistical performance of a representative group of hypothetical individuals responding to generalized situations.

  1. Post-event human decision errors: operator action tree/time reliability correlation

    International Nuclear Information System (INIS)

    Hall, R.E.; Fragola, J.; Wreathall, J.

    1982-11-01

    This report documents an interim framework for the quantification of the probability of errors of decision on the part of nuclear power plant operators after the initiation of an accident. The framework can easily be incorporated into an event tree/fault tree analysis. The method presented consists of a structure called the operator action tree and a time reliability correlation which assumes the time available for making a decision to be the dominating factor in situations requiring cognitive human response. This limited approach decreases the magnitude and complexity of the decision modeling task. Specifically, in the past, some human performance models have attempted prediction by trying to emulate sequences of human actions, or by identifying and modeling the information processing approach applicable to the task. The model developed here is directed at describing the statistical performance of a representative group of hypothetical individuals responding to generalized situations

  2. Estimating time-varying conditional correlations between stock and foreign exchange markets

    Science.gov (United States)

    Tastan, Hüseyin

    2006-02-01

    This study explores the dynamic interaction between stock market returns and changes in nominal exchange rates. Many financial variables are known to exhibit fat tails and autoregressive variance structure. It is well-known that unconditional covariance and correlation coefficients also vary significantly over time and multivariate generalized autoregressive model (MGARCH) is able to capture the time-varying variance-covariance matrix for stock market returns and changes in exchange rates. The model is applied to daily Euro-Dollar exchange rates and two stock market indexes from the US economy: Dow-Jones Industrial Average Index and S&P500 Index. The news impact surfaces are also drawn based on the model estimates to see the effects of idiosyncratic shocks in respective markets.

  3. Out-of-time-ordered correlators in a quantum Ising chain

    Science.gov (United States)

    Lin, Cheng-Ju; Motrunich, Olexei I.

    2018-04-01

    Out-of-time-ordered correlators (OTOC) have been proposed to characterize quantum chaos in generic systems. However, they can also show interesting behavior in integrable models, resembling the OTOC in chaotic systems in some aspects. Here we study the OTOC for different operators in the exactly-solvable one-dimensional quantum Ising spin chain. The OTOC for spin operators that are local in terms of the Jordan-Wigner fermions has a "shell-like" structure: After the wavefront passes, the OTOC approaches its original value in the long-time limit, showing no signature of scrambling; the approach is described by a t-1 power law at long time t . On the other hand, the OTOC for spin operators that are nonlocal in the Jordan-Wigner fermions has a "ball-like" structure, with its value reaching zero in the long-time limit, looking like a signature of scrambling; the approach to zero, however, is described by a slow power law t-1 /4 for the Ising model at the critical coupling. These long-time power-law behaviors in the lattice model are not captured by conformal field theory calculations. The mixed OTOC with both local and nonlocal operators in the Jordan-Wigner fermions also has a "ball-like" structure, but the limiting values and the decay behavior appear to be nonuniversal. In all cases, we are not able to define a parametrically large window around the wavefront to extract the Lyapunov exponent.

  4. Expansion and Compression of Time Correlate with Information Processing in an Enumeration Task.

    Directory of Open Access Journals (Sweden)

    Andreas Wutz

    Full Text Available Perception of temporal duration is subjective and is influenced by factors such as attention and context. For example, unexpected or emotional events are often experienced as if time subjectively expands, suggesting that the amount of information processed in a unit of time can be increased. Time dilation effects have been measured with an oddball paradigm in which an infrequent stimulus is perceived to last longer than standard stimuli in the rest of the sequence. Likewise, time compression for the oddball occurs when the duration of the standard items is relatively brief. Here, we investigated whether the amount of information processing changes when time is perceived as distorted. On each trial, an oddball stimulus of varying numerosity (1-14 items and duration was presented along with standard items that were either short (70 ms or long (1050 ms. Observers were instructed to count the number of dots within the oddball stimulus and to judge its relative duration with respect to the standards on that trial. Consistent with previous results, oddballs were reliably perceived as temporally distorted: expanded for longer standard stimuli blocks and compressed for shorter standards. The occurrence of these distortions of time perception correlated with perceptual processing; i.e. enumeration accuracy increased when time was perceived as expanded and decreased with temporal compression. These results suggest that subjective time distortions are not epiphenomenal, but reflect real changes in sensory processing. Such short-term plasticity in information processing rate could be evolutionarily advantageous in optimizing perception and action during critical moments.

  5. Time-correlated single-photon counting study of multiple photoluminescence lifetime components of silicon nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Diamare, D., E-mail: d.diamare@ee.ucl.ac.uk [Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom); Wojdak, M. [Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom); Lettieri, S. [Institute for Superconductors and Innovative Materials, National Council of Research (CNR-SPIN), Via Cintia 80126, Naples (Italy); Department of Physical Sciences, University of Naples “Federico II”, Via Cintia 80126, Naples (Italy); Kenyon, A.J. [Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom)

    2013-04-15

    We report time-resolved photoluminescence measurements of thin films of silica containing silicon nanoclusters (Si NCs), produced by PECVD and annealed at temperatures between 700 °C and 1150 °C. While the near infrared emission of Si NCs has long been studied, visible light emission has only recently attracted interest due to its very short decay times and its recently-reported redshift with decreasing NCs size. We analyse the PL decay dynamics in the range 450–700 nm with picosecond time resolution using Time Correlated Single Photon Counting. In the resultant multi-exponential decays two dominant components can clearly be distinguished: a very short component, in the range of hundreds of picoseconds, and a nanosecond component. In this wavelength range we do not detect the microsecond component generally associated with excitonic recombination. We associate the nanosecond component to defect relaxation: it decreases in intensity in the sample annealed at higher temperature, suggesting that the contribution from defects decreases with increasing temperature. The origin of the very fast PL component (ps time region) is also discussed. We show that it is consistent with the Auger recombination times of multiple excitons. Further work needs to be done in order to assess the contribution of the Auger-controlled recombinations to the defect-assisted mechanism of photoluminescence. -- Highlights: ► We report time-resolved PL measurements of Si-Ncs embedded in SiO{sub 2} matrix. ► Net decrease of PL with increasing the annealing temperature has been observed. ► Lifetime distribution analysis revealed a multiexponential decay with ns and ps components. ► Ps components are consistent with the lifetime range of the Auger recombination times. ► No evidence for a fast direct transition at the Brillouin zone centre.

  6. Measuring time-of-flight in an ultrasonic LPS system using generalized cross-correlation.

    Science.gov (United States)

    Villladangos, José Manuel; Ureña, Jesús; García, Juan Jesús; Mazo, Manuel; Hernández, Alvaro; Jiménez, Ana; Ruíz, Daniel; De Marziani, Carlos

    2011-01-01

    In this article, a time-of-flight detection technique in the frequency domain is described for an ultrasonic local positioning system (LPS) based on encoded beacons. Beacon transmissions have been synchronized and become simultaneous by means of the DS-CDMA (direct-sequence code Division multiple access) technique. Every beacon has been associated to a 255-bit Kasami code. The detection of signal arrival instant at the receiver, from which the distance to each beacon can be obtained, is based on the application of the generalized cross-correlation (GCC), by using the cross-spectral density between the received signal and the sequence to be detected. Prior filtering to enhance the frequency components around the carrier frequency (40 kHz) has improved estimations when obtaining the correlation function maximum, which implies an improvement in distance measurement precision. Positioning has been achieved by using hyperbolic trilateration, based on the time differences of arrival (TDOA) between a reference beacon and the others.

  7. Correlations of Eisenia fetida metabolic responses to extractable phenanthrene concentrations through time

    Energy Technology Data Exchange (ETDEWEB)

    McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda; Simpson, Andre J. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail, Toronto, Ontario, M1C 1A4 (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.c [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail, Toronto, Ontario, M1C 1A4 (Canada)

    2010-06-15

    Eisenia fetida earthworms were exposed to phenanthrene for thirty days to compare hydroxypropyl-beta-cyclodextrin (HPCD) extraction of soil and {sup 1}H NMR earthworm metabolomics as indicators of bioavailability. The phenanthrene 28-d LC{sub 50} value was 750 mg/kg (632-891, 95% confidence intervals) for the peat soil tested. The initial phenanthrene concentration was 319 mg/kg, which biodegraded to 16 mg/kg within 15 days, at which time HPCD extraction suggested that phenanthrene was no longer bioavailable. Multivariate statistical analysis of {sup 1}H NMR spectra for E. fetida tissue extracts indicated that phenanthrene exposed and control earthworms differed throughout the 30 day experiment despite the low phenanthrene concentrations present after 15 days. This metabolic response was better correlated to total phenanthrene concentrations (Q{sup 2} = 0.59) than HPCD-extractable phenanthrene concentrations (Q{sup 2} = 0.46) suggesting that {sup 1}H NMR metabolomics offers considerable promise as a novel, molecular-level method to directly monitor the bioavailability of contaminants to earthworms in the environment. - Metabolic responses of Eisenia fetida earthworms to phenanthrene exposure are better correlated to total phenanthrene concentrations than to cyclodextrin-extractable concentrations through time.

  8. Correlates of screen time among 8-19-year-old students in China.

    Science.gov (United States)

    Ye, Sunyue; Chen, Lijian; Wang, Qineng; Li, Qinggong

    2018-04-10

    Previous studies have shown that prolonged time spent on screen-based sedentary behavior was significantly associated with lower health status in children, independent of physical activity levels. The study aimed to explore the individual and environmental correlates of screen time (ST) among 8-19-year-old students in China. The study surveyed ST using a self-administered questionnaire in Chinese students aged 8-19 years; 1063 participants were included in the final analysis. Individual and environmental correlates of ST were assessed using a mixed-effects model (for continuous outcome variables) and multiple logistic regression model (for binary outcome variables). Prolonged ST was observed in 14.7% of boys and 8.9% of girls. Of the ST, weekend and mobile phone/tablet use represented 80% and 40%, respectively. A positive relationship was observed between media accessibility and ST in both boys and girls (p negative factor for longer ST (p mobile phone/tablet or a computer rather than viewing a TV, along with increased media accessibility, increased ST. These results indicate that greater media accessibility was positively associated and the presence of parents/others was negatively associated with prolonged ST in both Chinese boys and girls. Development of new and effective strategies against prolonged ST are required, especially for small screen device-based ST on weekends.

  9. Correlations of Eisenia fetida metabolic responses to extractable phenanthrene concentrations through time

    International Nuclear Information System (INIS)

    McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda; Simpson, Andre J.; Simpson, Myrna J.

    2010-01-01

    Eisenia fetida earthworms were exposed to phenanthrene for thirty days to compare hydroxypropyl-β-cyclodextrin (HPCD) extraction of soil and 1 H NMR earthworm metabolomics as indicators of bioavailability. The phenanthrene 28-d LC 50 value was 750 mg/kg (632-891, 95% confidence intervals) for the peat soil tested. The initial phenanthrene concentration was 319 mg/kg, which biodegraded to 16 mg/kg within 15 days, at which time HPCD extraction suggested that phenanthrene was no longer bioavailable. Multivariate statistical analysis of 1 H NMR spectra for E. fetida tissue extracts indicated that phenanthrene exposed and control earthworms differed throughout the 30 day experiment despite the low phenanthrene concentrations present after 15 days. This metabolic response was better correlated to total phenanthrene concentrations (Q 2 = 0.59) than HPCD-extractable phenanthrene concentrations (Q 2 = 0.46) suggesting that 1 H NMR metabolomics offers considerable promise as a novel, molecular-level method to directly monitor the bioavailability of contaminants to earthworms in the environment. - Metabolic responses of Eisenia fetida earthworms to phenanthrene exposure are better correlated to total phenanthrene concentrations than to cyclodextrin-extractable concentrations through time.

  10. Prevalence and correlates of drink driving within patrons of Australian night-time entertainment precincts.

    Science.gov (United States)

    Curtis, Ashlee; Coomber, Kerri; Hyder, Shannon; Droste, Nic; Pennay, Amy; Jenkinson, Rebecca; Mayshak, Richelle; Miller, Peter G

    2016-10-01

    Drink driving is a significant public health concern, and contributes to many road fatalities worldwide. The current study is the first to examine the prevalence and correlates of drink driving behavior in a sample of night-time entertainment precinct attendees in Australia. Interviews were conducted with 4214 night-time entertainment precinct attendees in two metropolitan and three regional cities in Australia. Seven correlates of self-reported drink driving were examined: gender, age, occupation, blood alcohol concentration (BAC), alcohol consumed prior to attending a licensed venue, energy drink consumption, and other drug consumption. Fourteen percent of night-time entertainment precinct attendees reported drink driving in the past three months. Bivariate logistic regression models indicated that males were significantly more likely than females to report drink driving in the past three months. Blue-collar workers and sales/clerical/administrative workers were significantly more likely to report drink driving behavior in the past three months than white-collar workers. The likelihood of reporting drink driving during the three months prior to interview significantly increased as BAC on the current night out increased, and when patrons reported engaging in pre-drinking or other drug use. The multivariate model presented a similar pattern of results, however BAC and pre-drinking on the night of the interview were no longer independent significant predictors. Males, blue collar/sales/clerical/administrative workers, and illicit drug consumers were more likely to report engaging in drink driving behavior than their counterparts. Interventions should focus on addressing the considerable proportion night-time entertainment precinct attendees who report engaging in drink driving behavior. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Rotating quantum Gaussian packets

    International Nuclear Information System (INIS)

    Dodonov, V V

    2015-01-01

    We study two-dimensional quantum Gaussian packets with a fixed value of mean angular momentum. This value is the sum of two independent parts: the ‘external’ momentum related to the motion of the packet center and the ‘internal’ momentum due to quantum fluctuations. The packets minimizing the mean energy of an isotropic oscillator with the fixed mean angular momentum are found. They exist for ‘co-rotating’ external and internal motions, and they have nonzero correlation coefficients between coordinates and momenta, together with some (moderate) amount of quadrature squeezing. Variances of angular momentum and energy are calculated, too. Differences in the behavior of ‘co-rotating’ and ‘anti-rotating’ packets are shown. The time evolution of rotating Gaussian packets is analyzed, including the cases of a charge in a homogeneous magnetic field and a free particle. In the latter case, the effect of initial shrinking of packets with big enough coordinate-momentum correlation coefficients (followed by the well known expansion) is discovered. This happens due to a competition of ‘focusing’ and ‘de-focusing’ in the orthogonal directions. (paper)

  12. Rotation, Stability and Transport

    Energy Technology Data Exchange (ETDEWEB)

    Connor, J. W.

    2007-07-01

    Tokamak plasmas can frequently exhibit high levels of rotation and rotation shear. This can usually be attributed to various sources: injection of momentum, e.g. through neutral beams, flows driven by plasma gradients or torques resulting from non-ambipolar particle loss; however, the source sometimes remains a mystery, such as the spontaneous rotation observed in Ohmic plasmas. The equilibrium rotation profile is given by the balance of these sources with transport and other losses; the edge boundary conditions can play an important role in determining this profile . Such plasma rotation, particularly sheared rotation, is predicted theoretically to have a significant influence on plasma behaviour. In the first place, sonic flows can significantly affect tokamak equilibria and neoclassical transport losses. However, the influence of rotation on plasma stability and turbulence is more profound. At the macroscopic level it affects the behaviour of the gross MHD modes that influence plasma operational limits. This includes sawteeth, the seeding of neoclassical tearing modes, resistive wall modes and the onset of disruptions through error fields, mode locking and reconnection. At the microscopic level it has a major effect on the stability of ballooning modes, both ideal MHD and drift wave instabilities such as ion temperature gradient (ITG) modes. In the non-linear state, as unstable drift waves evolve into turbulent structures, sheared rotation also tears apart eddies, thereby reducing the resulting transport. There is considerable experimental evidence for these effects on both MHD stability and plasma confinement. In particular, the appearance of improved confinement modes with transport barriers, such as edge H-mode barriers and internal transport barriers (ITBs) appears to correlate well with the presence of sheared plasma rotation. This talk will describe the theory underlying some of these phenomena involving plasma rotation, on both macroscopic and microscopic

  13. 8-Channel acquisition system for Time-Correlated Single-Photon Counting.

    Science.gov (United States)

    Antonioli, S; Miari, L; Cuccato, A; Crotti, M; Rech, I; Ghioni, M

    2013-06-01

    Nowadays, an increasing number of applications require high-performance analytical instruments capable to detect the temporal trend of weak and fast light signals with picosecond time resolution. The Time-Correlated Single-Photon Counting (TCSPC) technique is currently one of the preferable solutions when such critical optical signals have to be analyzed and it is fully exploited in biomedical and chemical research fields, as well as in security and space applications. Recent progress in the field of single-photon detector arrays is pushing research towards the development of high performance multichannel TCSPC systems, opening the way to modern time-resolved multi-dimensional optical analysis. In this paper we describe a new 8-channel high-performance TCSPC acquisition system, designed to be compact and versatile, to be used in modern TCSPC measurement setups. We designed a novel integrated circuit including a multichannel Time-to-Amplitude Converter with variable full-scale range, a D∕A converter, and a parallel adder stage. The latter is used to adapt each converter output to the input dynamic range of a commercial 8-channel Analog-to-Digital Converter, while the integrated DAC implements the dithering technique with as small as possible area occupation. The use of this monolithic circuit made the design of a scalable system of very small dimensions (95 × 40 mm) and low power consumption (6 W) possible. Data acquired from the TCSPC measurement are digitally processed and stored inside an FPGA (Field-Programmable Gate Array), while a USB transceiver allows real-time transmission of up to eight TCSPC histograms to a remote PC. Eventually, the experimental results demonstrate that the acquisition system performs TCSPC measurements with high conversion rate (up to 5 MHz/channel), extremely low differential nonlinearity (<0.04 peak-to-peak of the time bin width), high time resolution (down to 20 ps Full-Width Half-Maximum), and very low crosstalk between channels.

  14. Individual and environmental correlates of objectively measured sedentary time in Dutch and Belgian adults.

    Directory of Open Access Journals (Sweden)

    Femke van Nassau

    Full Text Available As the detrimental health effects of sedentary behaviour are well established, insight into the individual and environmental factors that influence adults' sedentary behaviour is needed. Most studies to date rely on self-reported measures of sedentary time. Therefore, the aim of the current study was to examine individual and environmental correlates of objectively measured sedentary time in Dutch and Belgian adults. Between March and August 2014, Belgian (n = 133 and Dutch (n = 223 adults, recruited as sub-sample of the SPOTLIGHT survey, wore an ActiGraph accelerometer to provide objectively measured sedentary and moderate to vigorous physical activity time. Participants completed a questionnaire assessing sociodemographic (country of residence, age, gender and educational level, lifestyle (sleep, smoking, sugar-containing beverage consumption, alcohol intake, health (body mass index, self-rated health, work (employment status and type of work, happiness, physical environmental (owning a car, number of screens, socioeconomic status and residential density and social environmental factors (social network, social cohesion. Univariate and multivariable regression analyses showed that Belgian participants had a lower odds of being sedentary for at least 9 hours per day compared to Dutch participants. Women, older participants and those meeting the WHO recommendation for physical activity were also less likely to sit for 9 hours or more per day. Participants doing (heavy manual work or being in education, homemaker, unemployed had lower odds of being sedentary for at least 9 hours per day compared to participants with a sitting job. Those with a higher self-reported social network also had lower odds for sedentary time. No associations between physical and other social environmental characteristics and sedentary time were found. Our findings add to the growing evidence of factors associated with prolonged sedentary time in adults. These findings may

  15. Effects of zonal flows on correlation between energy balance and energy conservation associated with nonlinear nonviscous atmospheric dynamics in a thin rotating spherical shell

    Science.gov (United States)

    Ibragimov, Ranis N.

    2018-03-01

    The nonlinear Euler equations are used to model two-dimensional atmosphere dynamics in a thin rotating spherical shell. The energy balance is deduced on the basis of two classes of functorially independent invariant solutions associated with the model. It it shown that the energy balance is exactly the conservation law for one class of the solutions whereas the second class of invariant solutions provides and asymptotic convergence of the energy balance to the conservation law.

  16. Scanless nonlinear optical microscope for image reconstruction and space-time correlation analysis

    Science.gov (United States)

    Ceffa, N. G.; Radaelli, F.; Pozzi, P.; Collini, M.; Sironi, L.; D'alfonso, L.; Chirico, G.

    2017-06-01

    Optical Microscopy has been applied to life science from its birth and reached widespread application due to its major advantages: limited perturbation of the biological tissue and the easy accessibility of the light sources. However, as the spatial and time resolution requirements and the time stability of the microscopes increase, researchers are struggling against some of its limitations: limited transparency and the refractivity of the living tissue to light and the field perturbations induced by the path in the tissue. We have developed a compact stand-alone, completely scan-less, optical setup that allows to acquire non-linear excitation images and to measure the sample dynamics simultaneously on an ensemble of arbitrary chosen regions of interests. The image is obtained by shining a square array of spots on the sample obtained by a spatial light modulator and by shifting it (10 ms refresh time) on the sample. The final image is computed from the superposition of (100-1000) images. Filtering procedures can be applied to the raw images of the excitation array before building the image. We discuss results that show how this setup can be used for the correction of wave front aberrations induced by turbid samples (such as living tissues) and for the computation of space-time cross-correlations in complex networks.

  17. Correlates of Leisure Time Physical Inactivity in a Scandinavian Population: A Basis for Interventions.

    Science.gov (United States)

    Bonn, Stephanie E; Alfredsson, Lars; Saevarsdottir, Saedis; Schelin, Maria E C

    2016-11-01

    Effective interventions are needed to increase physical activity in the general population. To target interventions, we need knowledge of insufficiently active groups in society. This study aims to identify demographic and health-related correlates of leisure-time physical inactivity in a general Scandinavian population. Study participants comprised 5734 control subjects, age 18 to 70 years, from 2 ongoing Swedish case-control studies. Participants self-reported their leisure-time physical activity level. The odds of being physically inactive were calculated using logistic regression. A total of 42% of participants were classified as physically inactive during leisure time. A lower prevalence of inactivity was associated with middle age, higher education, having previous experience of sports participation, following a low glycemic index/Mediterranean diet and having a light physical workload. A high prevalence of inactivity was associated with greater age, high body mass index, smoking, never drinking alcohol, having children, having a weak social network or lower levels of emotional support, and a low vegetable intake. Several factors were associated with leisure-time physical inactivity. Directing interventions to target groups defined by specific factors associated with physical inactivity could be an efficient way to increase activity and improve health in the general population.

  18. Particle correlation based measurement of the mean time between the deuteron and proton emissions

    International Nuclear Information System (INIS)

    Ghisalberti, C.; Lebrun, C.; Sezac, L.; Ardouin, D.; Erazmus, B.; Eudes, P.; Ghuilbault, F.; Lautridou, P.; Rahmani, J.A.; Reposeur, T.; Chbihi, A.; Galin, J.; Guerreau, D.; Morjean, M.; Peghaire, A.; Lednicky, R.; Pluta, J.; Quebert, J.; Siemssen, R.

    1997-01-01

    Proton-deuteron correlations at small relative momenta have been measured with the reaction 208 Pb + 93 Nb at 29 MeV per nucleon at GANIL using the ORION neutron calorimeter. By selecting the proton-deuteron pairs according to the angle between their relative velocity and the pair center of mass velocity of the emitting source one can determine the average value of the time delay between the emission of these particles. The results reported in this paper for the first time at GANIL energies agree with the values published before in the literature i.e. 600 and 1500 fm/c for deuteron and proton emission times, respectively, as obtained in the reactions Ar + Ag at E/A = 17 MeV. At higher energies measurements with a B.U.U. calorimeter recording the collisions 14 N + 27 Al at E/A = 75 MeV show that in this case the proton emission begins at 15 fm/c and decreases slowly in time, while the deuterons are emitted at 50 fm/c and present a steep falling. This result agrees with a negative average value of d - t p >. Thus, the method presented in this report for determining the order of emission is of great interest for checking the theoretical description of the particle emission all the way in the collision dynamical process

  19. U-shape rotating anti-cathode compact X-ray generator: 20 times stronger than the commercially available X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Sakabe, N., E-mail: sakabe-dsb@sbsp.jp; Sakabe, K. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801 (Japan); Foundation for Advancement of International Science (FAIS), Kasuga 3-chome, Tsukuba, Ibaraki 305-0821 (Japan); Ohsawa, S.; Sakai, T.; Kobayakawa, H.; Sugimura, T.; Ikeda, M.; Tawada, M. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Watanabe, N.; Sasaki, K. [Nagoya University, Chikusa, Nagoya, Aichi 464-8603 (Japan); Wakatsuki, M. [National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8568 (Japan)

    2013-11-01

    A new type of U-shape anti-cathode X-ray generator in which the inner surface of a cylindrical target is irradiated by an electron beam has been made by modifying a conventional rotating anti-cathode X-ray generator whose brightness in the catalog is 12 kW mm{sup −2}. A brightness of 129 kW mm{sup −2} was thereby obtained with this new U-shape-type X-ray generator. This new X-ray generator is expected to be of keen interest for applications in academia, industry and in hospitals. A new type of U-shape anti-cathode X-ray generator in which the inner surface of a cylindrical target is irradiated by an electron beam has been made by modifying a conventional rotating anti-cathode X-ray generator whose brightness in the catalog is 12 kW mm{sup −2}. The target material (Cu), target radius (50 mm) and rotating speed (6000 r.p.m.) were not changed in this modification. A brightness of 52 kW mm{sup −2} was obtained by this U-shape-type X-ray generator. This means that the brightness of the new type is 4.3 times greater than that of the old unmodified one. Furthermore, the new-type X-ray generator yielded a brightness of 129 kW mm{sup −2} by adding a carbon coating on the Cu target. This means an overall increase of brightness of ten times. The original generator has the highest brightness in the generators of the same class (having a radius of 50 mm and rotation speed of 6000 r.p.m.). Observations showed that Cu Kα counts at vertical incidence of the electron beam onto the surface of the new target, which is initially optically smooth, decrease as the surface is roughened by a severe thermal stress caused by strong electron beam exposure. Further observation reveals, however, that oblique incidence of the electron beam onto the roughened surface drastically increased the X-ray output and amounts to twice as much as that from a smooth surface at vertical incidence. Thus, at the present stage, an overall increase of brightness has been realised at a level 20 times

  20. Improved efficiency of maximum likelihood analysis of time series with temporally correlated errors

    Science.gov (United States)

    Langbein, John

    2017-08-01

    Most time series of geophysical phenomena have temporally correlated errors. From these measurements, various parameters are estimated. For instance, from geodetic measurements of positions, the rates and changes in rates are often estimated and are used to model tectonic processes. Along with the estimates of the size of the parameters, the error in these parameters needs to be assessed. If temporal correlations are not taken into account, or each observation is assumed to be independent, it is likely that any estimate of the error of these parameters will be too low and the estimated value of the parameter will be biased. Inclusion of better estimates of uncertainties is limited by several factors, including selection of the correct model for the background noise and the computational requirements to estimate the parameters of the selected noise model for cases where there are numerous observations. Here, I address the second problem of computational efficiency using maximum likelihood estimates (MLE). Most geophysical time series have background noise processes that can be represented as a combination of white and power-law noise, 1/f^{α } with frequency, f. With missing data, standard spectral techniques involving FFTs are not appropriate. Instead, time domain techniques involving construction and inversion of large data covariance matrices are employed. Bos et al. (J Geod, 2013. doi: 10.1007/s00190-012-0605-0) demonstrate one technique that substantially increases the efficiency of the MLE methods, yet is only an approximate solution for power-law indices >1.0 since they require the data covariance matrix to be Toeplitz. That restriction can be removed by simply forming a data filter that adds noise processes rather than combining them in quadrature. Consequently, the inversion of the data covariance matrix is simplified yet provides robust results for a wider range of power-law indices.

  1. Computational time-resolved and resonant x-ray scattering of strongly correlated materials

    Energy Technology Data Exchange (ETDEWEB)

    Bansil, Arun [Northeastern Univ., Boston, MA (United States)

    2016-11-09

    Basic-Energy Sciences of the Department of Energy (BES/DOE) has made large investments in x-ray sources in the U.S. (NSLS-II, LCLS, NGLS, ALS, APS) as powerful enabling tools for opening up unprecedented new opportunities for exploring properties of matter at various length and time scales. The coming online of the pulsed photon source, literally allows us to see and follow the dynamics of processes in materials at their natural timescales. There is an urgent need therefore to develop theoretical methodologies and computational models for understanding how x-rays interact with matter and the related spectroscopies of materials. The present project addressed aspects of this grand challenge of x-ray science. In particular, our Collaborative Research Team (CRT) focused on developing viable computational schemes for modeling x-ray scattering and photoemission spectra of strongly correlated materials in the time-domain. The vast arsenal of formal/numerical techniques and approaches encompassed by the members of our CRT were brought to bear through appropriate generalizations and extensions to model the pumped state and the dynamics of this non-equilibrium state, and how it can be probed via x-ray absorption (XAS), emission (XES), resonant and non-resonant x-ray scattering, and photoemission processes. We explored the conceptual connections between the time-domain problems and other second-order spectroscopies, such as resonant inelastic x-ray scattering (RIXS) because RIXS may be effectively thought of as a pump-probe experiment in which the incoming photon acts as the pump, and the fluorescent decay is the probe. Alternatively, when the core-valence interactions are strong, one can view K-edge RIXS for example, as the dynamic response of the material to the transient presence of a strong core-hole potential. Unlike an actual pump-probe experiment, here there is no mechanism for adjusting the time-delay between the pump and the probe. However, the core hole

  2. Preoperative diffusion-weighted imaging of single brain metastases correlates with patient survival times.

    Directory of Open Access Journals (Sweden)

    Anna Sophie Berghoff

    Full Text Available BACKGROUND: MRI-based diffusion-weighted imaging (DWI visualizes the local differences in water diffusion in vivo. The prognostic value of DWI signal intensities on the source images and apparent diffusion coefficient (ADC maps respectively has not yet been studied in brain metastases (BM. METHODS: We included into this retrospective analysis all patients operated for single BM at our institution between 2002 and 2010, in whom presurgical DWI and BM tissue samples were available. We recorded relevant clinical data, assessed DWI signal intensity and apparent diffusion coefficient (ADC values and performed histopathological analysis of BM tissues. Statistical analyses including uni- and multivariate survival analyses were performed. RESULTS: 65 patients (34 female, 31 male with a median overall survival time (OS of 15 months (range 0-99 months were available for this study. 19 (29.2% patients presented with hyper-, 3 (4.6% with iso-, and 43 (66.2% with hypointense DWI. ADCmean values could be determined in 32 (49.2% patients, ranged from 456.4 to 1691.8*10⁻⁶ mm²/s (median 969.5 and showed a highly significant correlation with DWI signal intensity. DWI hyperintensity correlated significantly with high amount of interstitial reticulin deposition. In univariate analysis, patients with hyperintense DWI (5 months and low ADCmean values (7 months had significantly worse OS than patients with iso/hypointense DWI (16 months and high ADCmean values (30 months, respectively. In multivariate survival analysis, high ADCmean values retained independent statistical significance. CONCLUSIONS: Preoperative DWI findings strongly and independently correlate with OS in patients operated for single BM and are related to interstitial fibrosis. Inclusion of DWI parameters into established risk stratification scores for BM patients should be considered.

  3. Leisure-time physical exercise : Prevalence, attitudinal correlates, and behavioral correlates among young Europeans from 21 countries

    NARCIS (Netherlands)

    Steptoe, A; Wardle, J; Fuller, R; Holte, A; Justo, J; Sanderman, R; Wichstrom, L; Wichstroem, L.

    1997-01-01

    Background. Increasing leisure time physical exercise is a major target of public health programs throughout the developed world, but few international comparisons of exercise habits among people from diverse cultures have been published, The objectives of this study were to assess the prevalence of

  4. Associated relaxation time and the correlation function for a tumor cell growth system subjected to color noises

    International Nuclear Information System (INIS)

    Wang Canjun; Wei Qun; Mei Dongcheng

    2008-01-01

    The associated relaxation time T c and the normalized correlation function C(s) for a tumor cell growth system subjected to color noises are investigated. Using the Novikov theorem and Fox approach, the steady probability distribution is obtained. Based on them, the expressions of T c and C(s) are derived by means of projection operator method, in which the effects of the memory kernels of the correlation function are taken into account. Performing the numerical computations, it is found: (1) With the cross-correlation intensity |λ|, the additive noise intensity α and the multiplicative noise self-correlation time τ 1 increasing, the tumor cell numbers can be restrained; And the cross-correlation time τ 3 , the multiplicative noise intensity D can induce the tumor cell numbers increasing; However, the additive noise self-correlation time τ 2 cannot affect the tumor cell numbers; The relaxation time T c is a stochastic resonant phenomenon, and the distribution curves exhibit a single-maximum structure with D increasing. (2) The cross-correlation strength λ weakens the related activity between two states of the tumor cell numbers at different time, and enhances the stability of the tumor cell growth system in the steady state; On the contrast, τ 1 and τ 3 enhance the related activity between two states at different time; However, τ 2 has no effect on the related activity between two states at different time

  5. Associated relaxation time and the correlation function for a tumor cell growth system subjected to color noises

    Science.gov (United States)

    Wang, Can-Jun; Wei, Qun; Mei, Dong-Cheng

    2008-03-01

    The associated relaxation time T and the normalized correlation function C(s) for a tumor cell growth system subjected to color noises are investigated. Using the Novikov theorem and Fox approach, the steady probability distribution is obtained. Based on them, the expressions of T and C(s) are derived by means of projection operator method, in which the effects of the memory kernels of the correlation function are taken into account. Performing the numerical computations, it is found: (1) With the cross-correlation intensity |λ|, the additive noise intensity α and the multiplicative noise self-correlation time τ increasing, the tumor cell numbers can be restrained; And the cross-correlation time τ, the multiplicative noise intensity D can induce the tumor cell numbers increasing; However, the additive noise self-correlation time τ cannot affect the tumor cell numbers; The relaxation time T is a stochastic resonant phenomenon, and the distribution curves exhibit a single-maximum structure with D increasing. (2) The cross-correlation strength λ weakens the related activity between two states of the tumor cell numbers at different time, and enhances the stability of the tumor cell growth system in the steady state; On the contrast, τ and τ enhance the related activity between two states at different time; However, τ has no effect on the related activity between two states at different time.

  6. A study of time management: the correlation between video game usage and academic performance markers.

    Science.gov (United States)

    Anand, Vivek

    2007-08-01

    This study analyzes the correlation between video game usage and academic performance. Scholastic Aptitude Test (SAT) and grade-point average (GPA) scores were used to gauge academic performance. The amount of time a student spends playing video games has a negative correlation with students' GPA and SAT scores. As video game usage increases, GPA and SAT scores decrease. A chi-squared analysis found a p value for video game usage and GPA was greater than a 95% confidence level (0.005 video game usage also returned a p value that was significant (0.01 video games may have a detrimental effect on an individual's GPA and possibly on SAT scores. Although these results show statistical dependence, proving cause and effect remains difficult, since SAT scores represent a single test on a given day. The effects of video games maybe be cumulative; however, drawing a conclusion is difficult because SAT scores represent a measure of general knowledge. GPA versus video games is more reliable because both involve a continuous measurement of engaged activity and performance. The connection remains difficult because of the complex nature of student life and academic performance. Also, video game usage may simply be a function of specific personality types and characteristics.

  7. Measurement system of correlation functions of microwave single photon source in real time

    Science.gov (United States)

    Korenkov, A.; Dmitriev, A.; Astafiev, O.

    2018-02-01

    Several quantum setups, such as quantum key distribution networks[1] and quantum simulators (e.g. boson sampling), by their design rely on single photon sources (SPSs). These quantum setups were demonstrated to operate in optical frequency domain. However, following the steady advances in circuit quantum electrodynamics, a proposal has been made recently[2] to demonstrate boson sampling with microwave photons. This in turn requires the development of reliable microwave SPS. It's one of the most important characteristics are the first-order and the second-order correlation functions g1 and g2. The measurement technique of g1 and g2 is significantly different from that in the optical domain [3],[4] because of the current unavailability of microwave single-photon detectors. In particular, due to high levels of noise present in the system a substantial amount of statistics in needed to be acquired. This work presents a platform for measurement of g1 and g2 that processes the incoming data in real time, maximizing the efficiency of data acquisition. The use of field-programmable gate array (FPGA) electronics, common in similar experiments[3] but complex in programming, is avoided; instead, the calculations are performed on a standard desktop computer. The platform is used to perform the measurements of the first-order and the second-order correlation functions of the microwave SPS.

  8. Evaluation of computed tomography coronary angiography in patients with a high heart rate using 16-slice spiral computed tomography with 0.37-s gantry rotation time

    International Nuclear Information System (INIS)

    Zhang, Shi-Zheng; Hu, Xiu-Hua; Zhang, Qiao-Wei; Huang, Wen-Xin

    2005-01-01

    The aim of our study is to evaluate computed tomography (CT) coronary angiography in patients with a high heart rate using 16-slice spiral CT with 0.37-s gantry rotation time. We compare the image quality of patients whose heart rates were over 70 beats per minute (bpm) with that of patients whose heart rates were 70 bpm or less. Sixty patients with various heart rates underwent retrospectively ECG-gated multislice spiral CT (MSCT) coronary angiography. Two experienced observers who were blind to the heart rates of the patients evaluated all the MSCT coronary angiographic images and calculated the assessable segments. A total of 620 out of 891 (69.6%) segments were satisfactorily visualized. On average, 10.3 coronary artery segments per patient could be evaluated. In 36 patients whose heart rates were below 70 bpm [mean 62.2 bpm±5.32 (standard deviation, SD)], the number of assessable segments was 10.72±2.02 (SD). In the other 24 patients whose heart rates were above 70 bpm [mean 78.6 bpm±8.24 (SD)], the corresponding number was 9.75±1.74 (SD). No statistically significant difference was found in these two subgroups' t test, P>0.05. The new generation of 16-slice spiral CT with 0.37-s rotation time can satisfactorily evaluate the coronary arteries of patients with high heart rates (above 70 bpm, up to 102 bpm). (orig.)

  9. A novel way to detect correlations on multi-time scales, with temporal evolution and for multi-variables

    Science.gov (United States)

    Yuan, Naiming; Xoplaki, Elena; Zhu, Congwen; Luterbacher, Juerg

    2016-06-01

    In this paper, two new methods, Temporal evolution of Detrended Cross-Correlation Analysis (TDCCA) and Temporal evolution of Detrended Partial-Cross-Correlation Analysis (TDPCCA), are proposed by generalizing DCCA and DPCCA. Applying TDCCA/TDPCCA, it is possible to study correlations on multi-time scales and over different periods. To illustrate their properties, we used two climatological examples: i) Global Sea Level (GSL) versus North Atlantic Oscillation (NAO); and ii) Summer Rainfall over Yangtze River (SRYR) versus previous winter Pacific Decadal Oscillation (PDO). We find significant correlations between GSL and NAO on time scales of 60 to 140 years, but the correlations are non-significant between 1865-1875. As for SRYR and PDO, significant correlations are found on time scales of 30 to 35 years, but the correlations are more pronounced during the recent 30 years. By combining TDCCA/TDPCCA and DCCA/DPCCA, we proposed a new correlation-detection system, which compared to traditional methods, can objectively show how two time series are related (on which time scale, during which time period). These are important not only for diagnosis of complex system, but also for better designs of prediction models. Therefore, the new methods offer new opportunities for applications in natural sciences, such as ecology, economy, sociology and other research fields.

  10. TIME SERIES ANALYSIS ON STOCK MARKET FOR TEXT MINING CORRELATION OF ECONOMY NEWS

    Directory of Open Access Journals (Sweden)

    Sadi Evren SEKER

    2014-01-01

    Full Text Available This paper proposes an information retrieval methodfor the economy news. Theeffect of economy news, are researched in the wordlevel and stock market valuesare considered as the ground proof.The correlation between stock market prices and economy news is an already ad-dressed problem for most of the countries. The mostwell-known approach is ap-plying the text mining approaches to the news and some time series analysis tech-niques over stock market closing values in order toapply classification or cluster-ing algorithms over the features extracted. This study goes further and tries to askthe question what are the available time series analysis techniques for the stockmarket closing values and which one is the most suitable? In this study, the newsand their dates are collected into a database and text mining is applied over thenews, the text mining part has been kept simple with only term frequency – in-verse document frequency method. For the time series analysis part, we havestudied 10 different methods such as random walk, moving average, acceleration,Bollinger band, price rate of change, periodic average, difference, momentum orrelative strength index and their variation. In this study we have also explainedthese techniques in a comparative way and we have applied the methods overTurkish Stock Market closing values for more than a2 year period. On the otherhand, we have applied the term frequency – inversedocument frequency methodon the economy news of one of the high-circulatingnewspapers in Turkey.

  11. Optical imaging through turbid media with a degenerate four wave mixing correlation time gate

    International Nuclear Information System (INIS)

    Sappey, A.D.

    1994-01-01

    A novel method for detection of ballistic light and rejection of unwanted diffusive light to image structures inside highly scattering media is demonstrated. Degenerate four wave mixing (DFWM) of a doubled YAG laser in Rhodamine 6G is used to provide an ultrafast correlation time gate to discriminate against light that has undergone multiple scattering and therefore lost memory of the structures inside the scattering medium. We present preliminary results that determine the nature of the DFWM grating, confirm the coherence time of the laser, prove the phase-conjugate nature of the signal beam, and determine the dependence of the signal (reflectivity) on dye concentration and laser intensity. Finally, we have obtained images of a test cross-hair pattern through highly turbid suspensions of whole milk in water that are opaque to the naked eye. These imaging experiments demonstrate the utility of DFWM for imaging through turbid media. Based on our results, the use of DFWM as an ultrafast time gate for the detection of ballistic light in optical mammography appears to hold great promise for improving the current state of the art

  12. Photoacoustic imaging in scattering media by combining a correlation matrix filter with a time reversal operator.

    Science.gov (United States)

    Rui, Wei; Tao, Chao; Liu, Xiaojun

    2017-09-18

    Acoustic scattering medium is a fundamental challenge for photoacoustic imaging. In this study, we reveal the different coherent properties of the scattering photoacoustic waves and the direct photoacoustic waves in a matrix form. Direct waves show a particular coherence on the antidiagonals of the matrix, whereas scattering waves do not. Based on this property, a correlation matrix filter combining with a time reversal operator is proposed to preserve the direct waves and recover the image behind a scattering layer. Both numerical simulations and photoacoustic imaging experiments demonstrate that the proposed approach effectively increases the image contrast and decreases the background speckles in a scattering medium. This study might improve the quality of photoacoustic imaging in an acoustic scattering environment and extend its applications.

  13. Relating Out-of-Time-Order Correlations to Entanglement via Multiple-Quantum Coherences.

    Science.gov (United States)

    Gärttner, Martin; Hauke, Philipp; Rey, Ana Maria

    2018-01-26

    Out-of-time-order correlations (OTOCs) characterize the scrambling, or delocalization, of quantum information over all the degrees of freedom of a system and thus have been proposed as a proxy for chaos in quantum systems. Recent experimental progress in measuring OTOCs calls for a more thorough understanding of how these quantities characterize complex quantum systems, most importantly in terms of the buildup of entanglement. Although a connection between OTOCs and entanglement entropy has been derived, the latter only quantifies entanglement in pure systems and is hard to access experimentally. In this work, we formally demonstrate that the multiple-quantum coherence spectra, a specific family of OTOCs well known in NMR, can be used as an entanglement witness and as a direct probe of multiparticle entanglement. Our results open a path to experimentally testing the fascinating idea that entanglement is the underlying glue that links thermodynamics, statistical mechanics, and quantum gravity.

  14. Correlation between real-time qPCR and development of strongyle eggs from cattle

    DEFF Research Database (Denmark)

    Drag, Markus; Nejsum, Peter; Höglund, Johan

    2014-01-01

    Differentiation of veterinary important parasitic strongyle eggs is time-consuming, because morphologically distinct third-stage larvae (L3) must be cultured for species/genus identification. A recently published qPCR technique provides a non-labour intensive method for detection and quantification...... of the two most important nematode eggs in cattle faeces. However, as quantification correlates with DNA content, quantification of copy numbers of the second internal transcribed spacer (ITS2) region is problematic as DNA content increases during egg development. The aim of this study was to assess...... the impact of oxygen availability and temperature on the multiplication of ITS2 copy numbers in O. ostertagi eggs. Fresh eggs were recovered from cattle faeces by sieving, flotation and entrapment in nylon-mesh filters and subsequently deposited in aliquots (n=18) of 5 ml distilled water with air circulation...

  15. Comparison of Solar and Wind Power Output and Correlation with Real-Time Pricing

    Science.gov (United States)

    Hoepfl, Kathryn E.; Compaan, Alvin D.; Solocha, Andrew

    2011-03-01

    This study presents a method that can be used to determine the least volatile power output of a wind and solar hybrid energy system in which wind and solar systems have the same peak power. Hourly data for wind and PV systems in Northwest Ohio are used to show that a combination of both types of sustainable energy sources produces a more stable power output and would be more valuable to the grid than either individually. This method could be used to determine the ideal ratio in any part of the country and should help convince electric utility companies to bring more renewable generation online. This study also looks at real-time market pricing and how each system (solar, wind, and hybrid) correlates with 2009 hourly pricing from the Midwest Interconnect. KEH acknowledges support from the NSF-REU grant PHY-1004649 to the Univ. of Toledo and Garland Energy Systems/Ohio Department of Development.

  16. Time Reversibility, Correlation Decay and the Steady State Fluctuation Relation for Dissipation

    Directory of Open Access Journals (Sweden)

    Denis J. Evans

    2013-04-01

    Full Text Available Steady state fluctuation relations for nonequilibrium systems are under intense investigation because of their important practical implications in nanotechnology and biology. However the precise conditions under which they hold need clarification. Using the dissipation function, which is related to the entropy production of linear irreversible thermodynamics, we show time reversibility, ergodic consistency and a recently introduced form of correlation decay, called T-mixing, are sufficient conditions for steady state fluctuation relations to hold. Our results are not restricted to a particular model and show that the steady state fluctuation relation for the dissipation function holds near or far from equilibrium subject to these conditions. The dissipation function thus plays a comparable role in nonequilibrium systems to thermodynamic potentials in equilibrium systems.

  17. Mean first-passage time of an asymmetric bistable system driven by colour-correlated noise

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiao-Yan; Xu Wei

    2007-01-01

    In this paper, the effect of every parameter (including p, q,r, λ,τ) on the mean first-passage time (MFPT) is investigated in an asymmetric bistable system driven by colour-correlated noise. The expression of MFPT has been obtained by applying the steepest-descent approximation. Numerical results show that (1) the intensity of multiplicative noise p and the intensity of additive noise q play different roles in the MFPT of the system, (2) suppression appears on the curve of the MFPT with small λ (e.g. λ< 0.5) but there is a peak on the curve of the MFPT when λ is big (e.g.λ> 0.5), and (3) with different values of r (e.g. r = 0.1, 0.5, 1.5), the effort of τ on the MFPT is diverse.

  18. In situ detection of warfarin using time-correlated single-photon counting

    Energy Technology Data Exchange (ETDEWEB)

    Rosengren, Annika M.; Karlsson, Bjoern C.G. [Bioorganic and Biophysical Chemistry Laboratory, School of Natural Sciences, Linnaeus University, SE-391 82 Kalmar (Sweden); Naeslund, Inga; Andersson, Per Ola [Swedish Defence Research Agency, FOI, CBRN Defence and Security, SE-901 82 Umea (Sweden); Nicholls, Ian A., E-mail: ian.a.nicholls@bioorg.uu.se [Bioorganic and Biophysical Chemistry Laboratory, School of Natural Sciences, Linnaeus University, SE-391 82 Kalmar (Sweden); Department of Biochemistry and Organic Chemistry Laboratory, Uppsala University, SE-751 23 Uppsala (Sweden)

    2011-04-01

    Highlights: {yields} Direct in situ measurement of specific isomeric forms of the anticoagulant warfarin. {yields} TCSPC spectroscopy in conjunction with synthetic Sudlow I binding site receptors. {yields} Development of sensor principle for use in clinical and environmental monitoring. -- Abstract: Here we report on a novel method for the direct in situ measurement of specific isomeric forms of the anticoagulant warfarin using time correlated single-photon counting (TCSPC) spectroscopy in conjunction with synthetic Sudlow I binding site receptors. The method is highly robust over the clinically significant concentration range, and demonstrates the potential of the binding site mimics in conjunction with the spectroscopic strategy employed here for the determination of this important pharmaceutical in clinical or even environmental samples.

  19. Thermal quantum time-correlation functions from classical-like dynamics

    Science.gov (United States)

    Hele, Timothy J. H.

    2017-07-01

    Thermal quantum time-correlation functions are of fundamental importance in quantum dynamics, allowing experimentally measurable properties such as reaction rates, diffusion constants and vibrational spectra to be computed from first principles. Since the exact quantum solution scales exponentially with system size, there has been considerable effort in formulating reliable linear-scaling methods involving exact quantum statistics and approximate quantum dynamics modelled with classical-like trajectories. Here, we review recent progress in the field with the development of methods including centroid molecular dynamics , ring polymer molecular dynamics (RPMD) and thermostatted RPMD (TRPMD). We show how these methods have recently been obtained from 'Matsubara dynamics', a form of semiclassical dynamics which conserves the quantum Boltzmann distribution. We also apply the Matsubara formalism to reaction rate theory, rederiving t → 0+ quantum transition-state theory (QTST) and showing that Matsubara-TST, like RPMD-TST, is equivalent to QTST. We end by surveying areas for future progress.

  20. Relating Out-of-Time-Order Correlations to Entanglement via Multiple-Quantum Coherences

    Science.gov (United States)

    Gärttner, Martin; Hauke, Philipp; Rey, Ana Maria

    2018-01-01

    Out-of-time-order correlations (OTOCs) characterize the scrambling, or delocalization, of quantum information over all the degrees of freedom of a system and thus have been proposed as a proxy for chaos in quantum systems. Recent experimental progress in measuring OTOCs calls for a more thorough understanding of how these quantities characterize complex quantum systems, most importantly in terms of the buildup of entanglement. Although a connection between OTOCs and entanglement entropy has been derived, the latter only quantifies entanglement in pure systems and is hard to access experimentally. In this work, we formally demonstrate that the multiple-quantum coherence spectra, a specific family of OTOCs well known in NMR, can be used as an entanglement witness and as a direct probe of multiparticle entanglement. Our results open a path to experimentally testing the fascinating idea that entanglement is the underlying glue that links thermodynamics, statistical mechanics, and quantum gravity.

  1. In situ detection of warfarin using time-correlated single-photon counting

    International Nuclear Information System (INIS)

    Rosengren, Annika M.; Karlsson, Bjoern C.G.; Naeslund, Inga; Andersson, Per Ola; Nicholls, Ian A.

    2011-01-01

    Highlights: → Direct in situ measurement of specific isomeric forms of the anticoagulant warfarin. → TCSPC spectroscopy in conjunction with synthetic Sudlow I binding site receptors. → Development of sensor principle for use in clinical and environmental monitoring. -- Abstract: Here we report on a novel method for the direct in situ measurement of specific isomeric forms of the anticoagulant warfarin using time correlated single-photon counting (TCSPC) spectroscopy in conjunction with synthetic Sudlow I binding site receptors. The method is highly robust over the clinically significant concentration range, and demonstrates the potential of the binding site mimics in conjunction with the spectroscopic strategy employed here for the determination of this important pharmaceutical in clinical or even environmental samples.

  2. Estimation of T2 relaxation time of breast cancer: Correlation with clinical, imaging and pathological features

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Mirinae; Sohn, Yu Mee [Dept. of Radiology, Kyung Hee University Hospital, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Ryu, Jung Kyu; Jahng, Geon Ho; Rhee, Sun Jung; Oh, Jang Hoon; Won, Kyu Yeoun [Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of)

    2017-01-15

    The purpose of this study was to estimate the T2* relaxation time in breast cancer, and to evaluate the association between the T2* value with clinical-imaging-pathological features of breast cancer. Between January 2011 and July 2013, 107 consecutive women with 107 breast cancers underwent multi-echo T2*-weighted imaging on a 3T clinical magnetic resonance imaging system. The Student's t test and one-way analysis of variance were used to compare the T2* values of cancer for different groups, based on the clinical-imaging-pathological features. In addition, multiple linear regression analysis was performed to find independent predictive factors associated with the T2* values. Of the 107 breast cancers, 92 were invasive and 15 were ductal carcinoma in situ (DCIS). The mean T2* value of invasive cancers was significantly longer than that of DCIS (p = 0.029). Signal intensity on T2-weighted imaging (T2WI) and histologic grade of invasive breast cancers showed significant correlation with T2* relaxation time in univariate and multivariate analysis. Breast cancer groups with higher signal intensity on T2WI showed longer T2* relaxation time (p = 0.005). Cancer groups with higher histologic grade showed longer T2* relaxation time (p = 0.017). The T2* value is significantly longer in invasive cancer than in DCIS. In invasive cancers, T2* relaxation time is significantly longer in higher histologic grades and high signal intensity on T2WI. Based on these preliminary data, quantitative T2* mapping has the potential to be useful in the characterization of breast cancer.

  3. Anomalous dispersion in correlated porous media: a coupled continuous time random walk approach

    Science.gov (United States)

    Comolli, Alessandro; Dentz, Marco

    2017-09-01

    We study the causes of anomalous dispersion in Darcy-scale porous media characterized by spatially heterogeneous hydraulic properties. Spatial variability in hydraulic conductivity leads to spatial variability in the flow properties through Darcy's law and thus impacts on solute and particle transport. We consider purely advective transport in heterogeneity scenarios characterized by broad distributions of heterogeneity length scales and point values. Particle transport is characterized in terms of the stochastic properties of equidistantly sampled Lagrangian velocities, which are determined by the flow and conductivity statistics. The persistence length scales of flow and transport velocities are imprinted in the spatial disorder and reflect the distribution of heterogeneity length scales. Particle transitions over the velocity length scales are kinematically coupled with the transition time through velocity. We show that the average particle motion follows a coupled continuous time random walk (CTRW), which is fully parameterized by the distribution of flow velocities and the medium geometry in terms of the heterogeneity length scales. The coupled CTRW provides a systematic framework for the investigation of the origins of anomalous dispersion in terms of heterogeneity correlation and the distribution of conductivity point values. We derive analytical expressions for the asymptotic scaling of the moments of the spatial particle distribution and first arrival time distribution (FATD), and perform numerical particle tracking simulations of the coupled CTRW to capture the full average transport behavior. Broad distributions of heterogeneity point values and lengths scales may lead to very similar dispersion behaviors in terms of the spatial variance. Their mechanisms, however are very different, which manifests in the distributions of particle positions and arrival times, which plays a central role for the prediction of the fate of dissolved substances in

  4. Energy-Efficient Optimization for HARQ Schemes over Time-Correlated Fading Channels

    KAUST Repository

    Shi, Zheng

    2018-03-19

    Energy efficiency of three common hybrid automatic repeat request (HARQ) schemes including Type I HARQ, HARQ with chase combining (HARQ-CC) and HARQ with incremental redundancy (HARQ-IR), is analyzed and joint power allocation and rate selection to maximize the energy efficiency is investigated in this paper. Unlike prior literature, time-correlated fading channels is considered and two widely concerned quality of service (QoS) constraints, i.e., outage and goodput constraints, are also considered in the optimization, which further differentiates this work from prior ones. Using a unified expression of asymptotic outage probabilities, optimal transmission powers and optimal rate are derived in closed-forms to maximize the energy efficiency while satisfying the QoS constraints. These closed-form solutions then enable a thorough analysis of the maximal energy efficiencies of various HARQ schemes. It is revealed that with low outage constraint, the maximal energy efficiency achieved by Type I HARQ is $\\\\frac{1}{4\\\\ln2}$ bits/J, while HARQ-CC and HARQ-IR can achieve the same maximal energy efficiency as $\\\\frac{\\\\kappa_\\\\infty}{4\\\\ln2}$ bits/J where $\\\\kappa_\\\\infty = 1.6617$. Moreover, time correlation in the fading channels has a negative impact on the energy efficiency, while large maximal allowable number of transmissions is favorable for the improvement of energy efficiency. The effectiveness of the energy-efficient optimization is verified by extensive simulations and the results also show that HARQ-CC can achieve the best tradeoff between energy efficiency and spectral efficiency among the three HARQ schemes.

  5. The correlation between fundamental characteristics and first-time performance in laparoscopic tasks.

    Science.gov (United States)

    Harrington, Cuan M; Bresler, Richard; Ryan, Donncha; Dicker, Patrick; Traynor, Oscar; Kavanagh, Dara O

    2018-04-01

    The ability of characteristics to predict first time performance in laparoscopic tasks is not well described. Videogame experience predicts positive performance in laparoscopic experiences but its mechanism and confounding-association with aptitude remains to be elucidated. This study sought to evaluate for innate predictors of laparoscopic performance in surgically naive individuals with minimal videogame exposure. Participants with no prior laparoscopic exposure and minimal videogaming experience were recruited consecutively from preclinical years at a medical university. Participants completed four visuospatial, one psychomotor aptitude test and an electronic survey, followed by four laparoscopic tasks on a validated Virtual Reality simulator (LAP Mentor™). Twenty eligible individuals participated with a mean age of 20.8 (±3.8) years. Significant intra-aptitude performance correlations were present amongst 75% of the visuospatial tests. These visuospatial aptitudes correlated significantly with multiple laparoscopic task metrics: number of movements of a dominant instrument (r s  ≥ -0.46), accuracy rate of clip placement (r s  ≥ 0.50) and time taken (r s  ≥ -0.47) (p < 0.05). Musical Instrument experience predicted higher average speed of instruments (r s  ≥ 0.47) (p < 0.05). Participant's revised competitive index level predicted lower proficiency in laparoscopic metrics including: pathlength, economy and number of movements of dominant instrument (r s  ≥ 0.46) (p < 0.05). Multiple visuospatial aptitudes and innate competitive level influenced baseline laparoscopic performances across several tasks in surgically naïve individuals. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Redesigning Schools to Reach Every Student with Excellent Teachers: Financial Planning for Time-Technology Swap--Rotation Model

    Science.gov (United States)

    Public Impact, 2012

    2012-01-01

    This brief shows how teachers in a Time-Technology swap school model may earn more, sustainably. In this model, schools use age-appropriate portions of digital learning (as little as about an hour daily per student) to free the time of excellent teachers to teach more students and potentially to collaborate with peers. By teaching more students,…

  7. Correlates of prolonged television viewing time in older Japanese men and women.

    Science.gov (United States)

    Kikuchi, Hiroyuki; Inoue, Shigeru; Sugiyama, Takemi; Owen, Neville; Oka, Koichiro; Shimomitsu, Teruichi

    2013-03-09

    (OR = 1.79, 95% CI 1.21-2.65), overweight (OR = 1.50, 95% CI: 1.00-2.24), and low MVPA (OR = 1.51. 95% CI: 1.05-2.17) were associated with prolonged TV time. These findings identify particular socio-demographic and behavioral characteristics related to TV time among Japanese older adults. It should be noted that correlates of prolonged TV time differed by gender. Women in living situations with limited transportation options tended to spend prolonged time watching TV. Health promotion initiatives for older adults, particularly for older women, may be more effective if they take these attributes into account.

  8. Time dependence of entropy flux and entropy production for a dynamical system driven by noises with coloured cross-correlation

    Institute of Scientific and Technical Information of China (English)

    Xie Wen-Xian; Xu Wei; Cai Li

    2007-01-01

    This paper shows the Fokker-Planck equation of a dynamical system driven by coloured cross-correlated white noises in the absence and presence of a small external force. Based on the Fokker-Planck equation and the definition of Shannon's information entropy, the time dependence of entropy flux and entropy production can be calculated. The present results can be used to explain the extremal behaviour of time dependence of entropy flux and entropy production in view of the dissipative parameter γ of the system, coloured cross-correlation time τ and coloured cross-correlation strength λ.

  9. A generic, time-resolved, integrated digital image correlation, identification approach

    NARCIS (Netherlands)

    Hoefnagels, J.P.M.; Neggers, J.; Blaysat, Benoît; Hild, François; Geers, M.G.D.; Jin, H.; Sciammarella, C.; Yoshida, S.; Lamberti, L.

    2015-01-01

    A generic one-step Integrated Digital Image Correlation (I-DIC) inverse parameter identification approach is introduced that enables direct identification of constitutive model parameters by intimately integrating a Finite Elements Method (FEM) with Digital Image Correlation (DIC), directly

  10. Measured time-correlated neutron-induced radiations in a sandstone formation. Final report

    International Nuclear Information System (INIS)

    Peters, C.; Karaoglan, E.; Ertel, J.; Brotzman, J.; Kennedy, C. Jr.

    1981-07-01

    The Grand Junction Operations Office, Department of Energy, via its contractor, The Bendix Field Engineering Corporation, is developing technologies to explore for uranium as a part of the National Uranium Resource Evaluation Program. This report is addressed to measurements of the inelastic- and capture-gamma rays induced by 14 MeV neutrons in uranium ore in a simulated sandstone formation. The associated-particle technique and timing correlation was used to measure the production of inelastic-gamma rays versus time and to separate the inelastic-gamma-ray energy spectrum from the capture-gamma-ray energy spectrum. The measurements of the fission-coincidence signal demonstrate that this technique appears to be very sensitive to the presence of uranium. These measurements indicate that the fission-coincidence signal would be improved for uranium assay by using a low-energy neutron source rather than 14-MeV neutrons. The results of these measurements demonstrate that the concept of the Borehole Neutron Diagnostic Probe is a promising new logging tool. Measurements for a wide variety of controlled borehole and formation parameters are needed to determine the optimum design and to calibrate the responses. These measurements should be performed with a prototype logging tool in formations that have densities closer to those found in the field than the simulated formation used in these measurements

  11. Conjugate gradient and cross-correlation based least-square reverse time migration and its application

    Science.gov (United States)

    Sun, Xiao-Dong; Ge, Zhong-Hui; Li, Zhen-Chun

    2017-09-01

    Although conventional reverse time migration can be perfectly applied to structural imaging it lacks the capability of enabling detailed delineation of a lithological reservoir due to irregular illumination. To obtain reliable reflectivity of the subsurface it is necessary to solve the imaging problem using inversion. The least-square reverse time migration (LSRTM) (also known as linearized reflectivity inversion) aims to obtain relatively high-resolution amplitude preserving imaging by including the inverse of the Hessian matrix. In practice, the conjugate gradient algorithm is proven to be an efficient iterative method for enabling use of LSRTM. The velocity gradient can be derived from a cross-correlation between observed data and simulated data, making LSRTM independent of wavelet signature and thus more robust in practice. Tests on synthetic and marine data show that LSRTM has good potential for use in reservoir description and four-dimensional (4D) seismic images compared to traditional RTM and Fourier finite difference (FFD) migration. This paper investigates the first order approximation of LSRTM, which is also known as the linear Born approximation. However, for more complex geological structures a higher order approximation should be considered to improve imaging quality.

  12. 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.

  13. Visuomotor mental rotation: the reaction time advantage for anti-pointing is not influenced by perceptual experience with the cardinal axes.

    Science.gov (United States)

    Neely, Kristina A; Heath, Matthew

    2010-03-01

    In the visuomotor mental rotation (VMR) paradigm, participants execute a center-out reaching movement to a location that deviates from a visual cue by a predetermined instruction angle. Previous work has demonstrated a linear increase in reaction time (RT) as a function of the amplitude of the instruction angle (Georgopoulos and Massey in Exp Brain Res 65:361-370, 1987). In contrast, we recently reported a RT advantage for an instruction angle of 180 degrees relative to a 90 degrees angle (Neely and Heath in Neurosci Lett 463:194-198, 2009). It is possible, however, that perceptual expertise with the cardinal axes, which are perceptually familiar reference frames, influenced the results of our previous investigation. To address this issue, we employed a VMR paradigm identical to that of our previous work, with the exception that the stimulus array was shifted 45 degrees from the horizontal and vertical meridians. Our results demonstrated that RTs were fastest and least variable when the instruction angle was 0 degrees, followed by 180 degrees, which in turn, was faster than 90 degrees. Such findings establish that the RT advantage for the 180 degrees instruction angle is not influenced by perceptual expertise with the cardinal axes. Moreover, the present results provide convergent evidence that RT is not determined by the angle of rotation; instead, they indicate that response latencies reflect computational differences in the complexity of response remapping.

  14. Evaluation of accuracy about 2D vs 3D real-time position management system based on couch rotation when non-coplanar respiratory gated radiation therapy

    International Nuclear Information System (INIS)

    Kwon, Kyung Tae; Kim, Jung Soo; Sim, Hyun Sun; Min, Jung Whan; Son, Soon Yong; Han, Dong Kyoon

    2016-01-01

    Because of non-coplanar therapy with couch rotation in respiratory gated radiation therapy, the recognition of marker movement due to the change in the distance between the infrared camera and the marker due to the rotation of the couch is called RPM (Real-time The purpose of this paper is to evaluate the accuracy of motion reflections (baseline changes) of 2D gating configuration (two dot marker block) and 3D gating configuration (six dot marker block). The motion was measured by varying the couch angle in the clockwise and counterclockwise directions by 10° in the 2D gating configuration. In the 3D gating configuration, the couch angle was changed by 10° in the clockwise direction and compared with the baseline at the reference 0°. The reference amplitude was 1.173 to 1.165, the couch angle at 20° was 1.132, and the couch angle at 1.0° was 1.083. At 350° counterclockwise, the reference amplitude was 1.168 to 1.157, the couch angle at 340° was 1.124, and the couch angle at 330° was 1.079. In this study, the phantom is used to quantitatively evaluate the value of the amplitude according to couch change

  15. Evaluation of accuracy about 2D vs 3D real-time position management system based on couch rotation when non-coplanar respiratory gated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Kyung Tae; Kim, Jung Soo [Dongnam Health University, Suwon (Korea, Republic of); Sim, Hyun Sun [College of Health Sciences, Korea University, Seoul (Korea, Republic of); Min, Jung Whan [Shingu University College, Sungnam (Korea, Republic of); Son, Soon Yong [Wonkwang Health Science University, Iksan (Korea, Republic of); Han, Dong Kyoon [College of Health Sciences, EulJi University, Daejeon (Korea, Republic of)

    2016-12-15

    Because of non-coplanar therapy with couch rotation in respiratory gated radiation therapy, the recognition of marker movement due to the change in the distance between the infrared camera and the marker due to the rotation of the couch is called RPM (Real-time The purpose of this paper is to evaluate the accuracy of motion reflections (baseline changes) of 2D gating configuration (two dot marker block) and 3D gating configuration (six dot marker block). The motion was measured by varying the couch angle in the clockwise and counterclockwise directions by 10° in the 2D gating configuration. In the 3D gating configuration, the couch angle was changed by 10° in the clockwise direction and compared with the baseline at the reference 0°. The reference amplitude was 1.173 to 1.165, the couch angle at 20° was 1.132, and the couch angle at 1.0° was 1.083. At 350° counterclockwise, the reference amplitude was 1.168 to 1.157, the couch angle at 340° was 1.124, and the couch angle at 330° was 1.079. In this study, the phantom is used to quantitatively evaluate the value of the amplitude according to couch change.

  16. Time-correlated pulse-height measurements of low-multiplying nuclear materials

    Energy Technology Data Exchange (ETDEWEB)

    Miller, E.C., E-mail: ericcm@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI (United States); Dolan, J.L.; Clarke, S.D.; Pozzi, S.A. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI (United States); Tomanin, A.; Peerani, P. [European Commission EC-JRC-IPSC, Ispra (Italy); Marleau, P. [Sandia National Laboratories, Livermore, CA (United States); Mattingly, J.K. [North Carolina State University, Raleigh, NC (United States)

    2013-11-21

    Methods for the determination of the subcritical neutron multiplication of nuclear materials are of interest in the field of nuclear nonproliferation and safeguards. A series of measurements were performed at the Joint Research Center facility in Ispra, Italy to investigate the possibility of using a time-correlated pulse-height (TCPH) analysis to estimate the sub-critical multiplication of nuclear material. The objective of the measurements was to evaluate the effectiveness of this technique, and to benchmark the simulation capabilities of MCNPX-PoliMi/MPPost. In this campaign, two low-multiplication samples were measured: a 1-kg mixed oxide (MOX) powder sample and several low-mass plutonium–gallium (PuGa) disks. The measured results demonstrated that the sensitivity of the TCPH technique could not clearly distinguish samples with very-low levels of multiplication. However, the simulated TCPH distributions agree well with the measured data, within 12% for all cases, validating the simulation capabilities of MCNPX-PoliMi/MPPost. To investigate the potential of the TCPH method for identifying high-multiplication samples, the validated MCNPX-PoliMi/MPPost codes were used to simulate sources of higher multiplications. Lastly, a characterization metric, the cumulative region integral (CRI), was introduced to estimate the level of multiplication in a source. However, this response was shown to be insensitive over the range of multiplications of interest. -- Highlights: •Present results of measurements of MOX fuel and PuGa disks. •Compared measurement results to simulations performed using MCNPX-Polimi and MPPost. •Investigated using correlated γ–n pairs to determine the multiplication of a system.

  17. Do Standard Bibliometric Measures Correlate with Academic Rank of Full-Time Pediatric Dentistry Faculty Members?

    Science.gov (United States)

    Susarla, Harlyn K; Dhar, Vineet; Karimbux, Nadeem Y; Tinanoff, Norman

    2017-04-01

    The aim of this cross-sectional study was to assess the relationship between quantitative measures of research productivity and academic rank for full-time pediatric dentistry faculty members in accredited U.S. and Canadian residency programs. For each pediatric dentist in the study group, academic rank and bibliometric factors derived from publicly available databases were recorded. Academic ranks were lecturer/instructor, assistant professor, associate professor, and professor. Bibliometric factors were mean total number of publications, mean total number of citations, maximum number of citations for a single work, and h-index (a measure of the impact of publications, determined by total number of publications h that had at least h citations each). The st