Estimation of Time-Varying Coherence and Its Application in Understanding Brain Functional Connectivity

Directory of Open Access Journals (Sweden)

Cheng Liu

2010-01-01

Full Text Available Time-varying coherence is a powerful tool for revealing functional dynamics between different regions in the brain. In this paper, we address ways of estimating evolutionary spectrum and coherence using the general Cohen's class distributions. We show that the intimate connection between the Cohen's class-based spectra and the evolutionary spectra defined on the locally stationary time series can be linked by the kernel functions of the Cohen's class distributions. The time-varying spectra and coherence are further generalized with the Stockwell transform, a multiscale time-frequency representation. The Stockwell measures can be studied in the framework of the Cohen's class distributions with a generalized frequency-dependent kernel function. A magnetoencephalography study using the Stockwell coherence reveals an interesting temporal interaction between contralateral and ipsilateral motor cortices under the multisource interference task.

Coherent optical effect on time-resolved vibrational SFG spectrum of adsorbates

Science.gov (United States)

Ueba, H.; Sawabu, T.; Mii, T.

2002-04-01

We present a theory to study the influence of the coherent mixing between pump-infrared and probe-visible pulse on a time-resolved sum-frequency generation (TR-SFG) spectrum for vibrations at surfaces. The general formula of the time-dependent and its Fourier transform of the SFG polarization and its Fourier transform allows us to calculate the time-resolved vibrational SFG spectrum and the transient characteristics of the SFG intensity as a function of the delay time td between the pump-infrared and probe-visible pulse. It is found the coherent optical effect manifests itself in the broadening and narrowing of the SFG spectrum with the intrinsic width of T2 at negative and positive td, respectively, being in qualitative agreement with recent experimental results. The influence of the coherent mixing on the transient behavior of the SFG intensity is also discussed in conjunction to the T2 determination.

Prolonged multifocal electroretinographic implicit times in the ocular ischemic syndrome

DEFF Research Database (Denmark)

Kofoed, Peter Kristian; Munch, Inger Christine; Sander, Birgit

2010-01-01

.4 +/- 1.7 mm Hg, respectively. Summed mfERG implicit times (N1, P1, N2) were prolonged in eyes with OIS, by 7.6%, 6.2%, and 7.5%, respectively, compared with fellow eyes (P macula, whereas the assessment of responses from...

Coherent combining pulse bursts in time domain

Science.gov (United States)

Galvanauskas, Almantas

2018-01-09

A beam combining and pulse stacking technique is provided that enhances laser pulse energy by coherent stacking pulse bursts (i.e. non-periodic pulsed signals) in time domain. This energy enhancement is achieved by using various configurations of Fabry-Perot, Gires-Tournois and other types of resonant cavities, so that a multiple-pulse burst incident at either a single input or multiple inputs of the system produces an output with a solitary pulse, which contains the summed energy of the incident multiple pulses from all beams. This disclosure provides a substantial improvement over conventional coherent-combining methods in that it achieves very high pulse energies using a relatively small number of combined laser systems, thus providing with orders of magnitude reduction in system size, complexity, and cost compared to current combining approaches.

On the possibility of superconducting phase coherence through time barriers

International Nuclear Information System (INIS)

Barone, A.; Kulik, I.O.

1993-01-01

The possibility of the occurrence of weak coupling between the superconducting order parameters in a single superconductor before and after an ultrashot quenching of superconductivity, is analyzed. The time barrier corresponding to such a quenching of the order parameter has to be shorter than, or comparable with, the characteristic 'coherence time' τ ∼ = Δ. Such an effect is somewhat analogous to a Josephson effect in which phase difference is now considered in the time domain rather than in space. A qualitative derivation of the constitutive relation for such a weak time correlation is obtained which gives, by the duality condition, a dependence of the supercharge on the time phase difference. The role of high-T c superconductors in the detection of this coherent transient response appears to be quite relevant. 21 refs., 4 figs

Real time 1.55 μm VCSEL-based coherent detection link

DEFF Research Database (Denmark)

Rodes Lopez, Roberto; Parekh, D.; Jensen, Jesper Bevensee

2012-01-01

This paper presents an experimental demonstration of VCSEL-based PON with simplified real-time coherent receiver at 2.5 Gbps. Receiver sensitivity of −37 dBm is achieved proving splitting ratio up to 2048 after 17 km fiber transmission.......This paper presents an experimental demonstration of VCSEL-based PON with simplified real-time coherent receiver at 2.5 Gbps. Receiver sensitivity of −37 dBm is achieved proving splitting ratio up to 2048 after 17 km fiber transmission....

Progress in coherent laser radar

Science.gov (United States)

Vaughan, J. M.

1986-01-01

Considerable progress with coherent laser radar has been made over the last few years, most notably perhaps in the available range of high performance devices and components and the confidence with which systems may now be taken into the field for prolonged periods of operation. Some of this increasing maturity was evident at the 3rd Topical Meeting on Coherent Laser Radar: Technology and Applications. Topics included in discussions were: mesoscale wind fields, nocturnal valley drainage and clear air down bursts; airborne Doppler lidar studies and comparison of ground and airborne wind measurement; wind measurement over the sea for comparison with satellite borne microwave sensors; transport of wake vortices at airfield; coherent DIAL methods; a newly assembled Nd-YAG coherent lidar system; backscatter profiles in the atmosphere and wavelength dependence over the 9 to 11 micrometer region; beam propagation; rock and soil classification with an airborne 4-laser system; technology of a global wind profiling system; target calibration; ranging and imaging with coherent pulsed and CW system; signal fluctuations and speckle. Some of these activities are briefly reviewed.

Quantum Coherence, Time-Translation Symmetry, and Thermodynamics

Directory of Open Access Journals (Sweden)

Matteo Lostaglio

2015-04-01

Full Text Available The first law of thermodynamics imposes not just a constraint on the energy content of systems in extreme quantum regimes but also symmetry constraints related to the thermodynamic processing of quantum coherence. We show that this thermodynamic symmetry decomposes any quantum state into mode operators that quantify the coherence present in the state. We then establish general upper and lower bounds for the evolution of quantum coherence under arbitrary thermal operations, valid for any temperature. We identify primitive coherence manipulations and show that the transfer of coherence between energy levels manifests irreversibility not captured by free energy. Moreover, the recently developed thermomajorization relations on block-diagonal quantum states are observed to be special cases of this symmetry analysis.

Paternal work stress and prolonged time to pregnancy.

Science.gov (United States)

Lee, Mi-Sun; Paek, Domyung; Eum, Ki-Do; Siegrist, Johannes; Li, Jian; Lee, Hye-Eun; Cho, Sung-Il

2009-01-01

The aim of this study was to explore an association between psychosocial stress at work in married men and their spouses' prolonged time to pregnancy (TTP). All married male workers of a large Korean petrochemical enterprise and their wives fulfilling the selection criteria were included. Main selection criteria were lack of use of contraceptives and experienced pregnancy in recent past. Data were available from 322 couples. Psychosocial stress at work was measured by the effort-reward imbalance questionnaire. Prolonged TTP was measured by the "TTP questionnaire". After adjustment for confounding effects of demographic and life-style characteristics and benzene exposure, delayed TTP, defined by frequency of first-cycle pregnancy, was associated with one standard deviation (SD) increase of the effort-reward ratio in the chronically stressed group of married men (OR = 0.47; 95% CI = 0.22-0.99) in logistic regression analysis. A similar, but somewhat weaker effect, was found for the overall group (OR = 0.67; 95% CI = 0.47-0.94). Paternal stress at work, as measured by effort-reward imbalance, seemed to be associated with a decreased number of conceptions in the first menstrual cycle.

Coherent exciton transport in dendrimers and continuous-time quantum walks

Science.gov (United States)

Mülken, Oliver; Bierbaum, Veronika; Blumen, Alexander

2006-03-01

We model coherent exciton transport in dendrimers by continuous-time quantum walks. For dendrimers up to the second generation the coherent transport shows perfect recurrences when the initial excitation starts at the central node. For larger dendrimers, the recurrence ceases to be perfect, a fact which resembles results for discrete quantum carpets. Moreover, depending on the initial excitation site, we find that the coherent transport to certain nodes of the dendrimer has a very low probability. When the initial excitation starts from the central node, the problem can be mapped onto a line which simplifies the computational effort. Furthermore, the long time average of the quantum mechanical transition probabilities between pairs of nodes shows characteristic patterns and allows us to classify the nodes into clusters with identical limiting probabilities. For the (space) average of the quantum mechanical probability to be still or to be again at the initial site, we obtain, based on the Cauchy-Schwarz inequality, a simple lower bound which depends only on the eigenvalue spectrum of the Hamiltonian.

10 Gb/s Real-Time All-VCSEL Low Complexity Coherent scheme for PONs

DEFF Research Database (Denmark)

Rodes Lopez, Roberto; Cheng, Ning; Jensen, Jesper Bevensee

2012-01-01

Real time demodulation of a 10 Gb/s all-VCSEL based coherent PON link with a simplified coherent receiver scheme is demonstrated. Receiver sensitivity of −33 dBm is achieved providing high splitting ratio and link reach....

Coherent states for FLRW space-times in loop quantum gravity

International Nuclear Information System (INIS)

Magliaro, Elena; Perini, Claudio; Marciano, Antonino

2011-01-01

We construct a class of coherent spin-network states that capture properties of curved space-times of the Friedmann-Lamaitre-Robertson-Walker type on which they are peaked. The data coded by a coherent state are associated to a cellular decomposition of a spatial (t=const) section with a dual graph given by the complete five-vertex graph, though the construction can be easily generalized to other graphs. The labels of coherent states are complex SL(2,C) variables, one for each link of the graph, and are computed through a smearing process starting from a continuum extrinsic and intrinsic geometry of the canonical surface. The construction covers both Euclidean and Lorentzian signatures; in the Euclidean case and in the limit of flat space we reproduce the simplicial 4-simplex semiclassical states used in spin foams.

Prolonged operative time increases infection rate in tibial plateau fractures.

Science.gov (United States)

Colman, Matthew; Wright, Adam; Gruen, Gary; Siska, Peter; Pape, Hans-Christoph; Tarkin, Ivan

2013-02-01

Fractures of the tibial plateau present a treatment challenge and are susceptible to both prolonged operative times and high postoperative infection rates. For those fractures treated with open plating, we sought to identify the relationship between surgical site infection and prolonged operative time as well as to identify other surgical risk factors. We performed a retrospective controlled analysis of 309 consecutive unicondylar and bicondylar tibial plateau fractures treated with open plate osteosynthesis at our institution's level I trauma centre during a recent 5-year period. We recorded operative times, injury characteristics, surgical treatment, and need for operative debridement due to infection. Operative times of infected cases were compared to uncomplicated surgical cases. Multivariable logistic regression analysis was performed to identify independent risk factors for postoperative infection. Mean operative time in the infection group was 2.8h vs. 2.2h in the non-infected group (p=0.005). 15 fractures (4.9%) underwent four compartment fasciotomies as part of their treatment, with a significantly higher infection rate than those not undergoing fasciotomy (26.7% vs. 6.8%, p=0.01). Open fracture grade was also significantly related to infection rate (closed fractures: 5.3%, grade 1: 14.3%, grade 2: 40%, grade 3: 50%, pinfection rates (13.9% vs. 8.7%, p=0.36). Multivariable logistic regression analysis of the entire study group identified longer operative times (OR 1.78, p=0.013) and open fractures (OR 7.02, psite infection. Operative times approaching 3h and open fractures are related to an increased overall risk for surgical site infection after open plating of the tibial plateau. Dual incision approaches with bicolumnar plating do not appear to expose the patient to increased risk compared to single incision approaches. Copyright © 2012 Elsevier Ltd. All rights reserved.

Nonadiabatic Dynamics May Be Probed through Electronic Coherence in Time-Resolved Photoelectron Spectroscopy.

Science.gov (United States)

Bennett, Kochise; Kowalewski, Markus; Mukamel, Shaul

2016-02-09

We present a hierarchy of Fermi golden rules (FGRs) that incorporate strongly coupled electronic/nuclear dynamics in time-resolved photoelectron spectroscopy (TRPES) signals at different levels of theory. Expansion in the joint electronic and nuclear eigenbasis yields the numerically most challenging exact FGR (eFGR). The quasistatic Fermi Golden Rule (qsFGR) neglects nuclear motion during the photoionization process but takes into account electronic coherences as well as populations initially present in the pumped matter as well as those generated internally by coupling between electronic surfaces. The standard semiclassical Fermi Golden Rule (scFGR) neglects the electronic coherences and the nuclear kinetic energy during the ionizing pulse altogether, yielding the classical Condon approximation. The coherence contributions depend on the phase-profile of the ionizing field, allowing coherent control of TRPES signals. The photoelectron spectrum from model systems is simulated using these three levels of theory. The eFGR and the qsFGR show temporal oscillations originating from the electronic or vibrational coherences generated as the nuclear wave packet traverses a conical intersection. These oscillations, which are missed by the scFGR, directly reveal the time-evolving splitting between electronic states of the neutral molecule in the curve-crossing regime.

Pulsed EPR study of spin coherence time of P donors in isotopically controlled Si

International Nuclear Information System (INIS)

Abe, Eisuke; Isoya, Junichi; Itoh, Kohei M.

2006-01-01

We investigate spin coherence time of electrons bound to phosphorus donors in silicon single crystals. The samples are isotopically controlled so that they may possess various concentrations (from 4.7% to 99.2%) of 29 Si, which is the only non-zero-spin stable isotope of silicon. The orientation dependence of electron-spin coherence times are presented, and electron spin echo envelope modulation is analyzed in time-frequency space

Donor Diabetes and Prolonged Cold Ischemia Time Synergistically Increase the Risk of Graft Failure After Liver Transplantation

NARCIS (Netherlands)

Brüggenwirth, Isabel M A; Dolgin, Natasha H; Porte, Robert J; Bozorgzadeh, Adel; Martins, Paulo N A

BACKGROUND: Both prolonged cold ischemia time (CIT) and donor history of diabetes mellitus (DM) are associated with reduced graft survival after liver transplantation. However, it is unknown whether the adverse effect of prolonged CIT on posttransplant graft survival is more pronounced after

Associations between prolonged sedentary time and breaks in sedentary time with cardiometabolic risk in 10-14-year-old children: The HAPPY study.

Science.gov (United States)

Bailey, Daniel P; Charman, Sarah J; Ploetz, Thomas; Savory, Louise A; Kerr, Catherine J

2017-11-01

This study examines the association between prolonged sedentary time and breaks in sedentary time with cardiometabolic risk in 10-14-year-old children. This cross-sectional design study analysed accelerometry-determined sedentary behaviour and physical activity collected over 7 days from 111 (66 girls) UK schoolchildren. Objective outcome measures included waist circumference, fasting lipids, fasting glucose, blood pressure, and cardiorespiratory fitness. Logistic regression was used for the main data analysis. After adjustment for confounders, the odds of having hypertriglyceridaemia (P = 0.03) and an increased clustered cardiometabolic risk score (P = 0.05) were significantly higher in children who engaged in more prolonged sedentary bouts per day. The number of breaks in sedentary time per day was not associated with any cardiometabolic risk factor, but longer mean duration of daily breaks in sedentary time were associated with a lower odds of having abdominal adiposity (P = 0.04) and elevated diastolic blood pressure (P = 0.01). These associations may be mediated by engagement in light activity. This study provides evidence that avoiding periods of prolonged uninterrupted sedentary time may be important for reducing cardiometabolic disease risk in children.

Quantum coherence and entanglement control for atom-cavity systems

Science.gov (United States)

Shu, Wenchong

Coherence and entanglement play a significant role in the quantum theory. Ideal quantum systems, "closed" to the outside world, remain quantum forever and thus manage to retain coherence and entanglement. Real quantum systems, however, are open to the environment and are therefore susceptible to the phenomenon of decoherence and disentanglement which are major hindrances to the effectiveness of quantum information processing tasks. In this thesis we have theoretically studied the evolution of coherence and entanglement in quantum systems coupled to various environments. We have also studied ways and means of controlling the decay of coherence and entanglement. We have studied the exact qubit entanglement dynamics of some interesting initial states coupled to a high-Q cavity containing zero photon, one photon, two photons and many photons respectively. We have found that an initially correlated environmental state can serve as an enhancer for entanglement decay or generation processes. More precisely, we have demonstrated that the degree of entanglement, including its collapse as well as its revival times, can be significantly modified by the correlated structure of the environmental modes. We have also studied dynamical decoupling (DD) technique --- a prominent strategy of controlling decoherence and preserving entanglement in open quantum systems. We have analyzed several DD control methods applied to qubit systems that can eliminate the system-environment coupling and prolong the quantum coherence time. Particularly, we have proposed a new DD sequence consisting a set of designed control operators that can universally protected an unknown qutrit state against colored phase and amplitude environment noises. In addition, in a non-Markovian regime, we have reformulated the quantum state diffusion (QSD) equation to incorporate the effect of the external control fields. Without any assumptions on the system-environment coupling and the size of environment, we have

An MLS coherence function and its performance in measurements on time-varying systems

DEFF Research Database (Denmark)

Liu, Jiyuan; Jacobsen, Finn

1999-01-01

A new MLS coherence function has been developed and tested in various room acoustic measurements. The new measure, which takes values between zero and unity just as the ordinary coherence, can be used only if averaging over several periods of the MLS signal is carried out. It indicates possible...... contamination by extraneous noise in the same manner as the the ordinary coherence function does in measurements with FFT analysers. It is also very sensitive to disturbances such as reflections caused by moving surfaces during the measurement. Very weak time-variance effects caused by a small change...

Effect of prolonging radiation delivery time on retention of gammaH2AX

International Nuclear Information System (INIS)

Moiseenko, Vitali; Banáth, Judit P; Duzenli, Cheryl; Olive, Peggy L

2008-01-01

Compared to conventional external beam radiotherapy, IMRT requires significantly more time to deliver the dose. Prolonging dose delivery potentially increases DNA repair which would reduce the biological effect. We questioned whether retention of γH2AX, a measure of lack of repair of DNA damage, would decrease when dose delivery was protracted. Exponentially growing SiHa cervical carinoma cells were irradiated with 6 MV photons in a water tank using a VarianEX linear accelerator. Cells held at 37°C received 2 Gy in 0.5 min and 4 Gy in 1 min. To evaluate effect of dose delivery prolongation, 2 and 4 Gy were delivered in 30 and 60 min. After 24 h recovery, cells were analyzed for clonogenic survival and for residual γH2AX as measured using flow cytometry. Increasing the dose delivery time from 0.5 or 1 min to 30 or 60 min produced a signficant increase in cell survival from 0.45 to 0.48 after 2 Gy, and from 0.17 to 0.20 after 4 Gy. Expression of residual γH2AX decreased from 1.27 to 1.22 relative to background after 2 Gy and 1.46 to 1.39 relative to background after 4 Gy, but differences were not statistically significant. The relative differences in the slopes of residual γH2AX versus dose for acute versus prolonged irradiation bordered on significant (p = 0.055), and the magnitude of the change was consistent with the observed increase in surviving fraction. These results support the concept that DNA repair underlies the increase in survival observed when dose delivery is prolonged. They also help to establish the limits of sensitivity of residual γH2AX, as measured using flow cytometry, for detecting differences in response to irradiation

Electron Spin Coherence Times in Si/SiGe Quantum Dots

Science.gov (United States)

Jock, R. M.; He, Jianhua; Tyryshkin, A. M.; Lyon, S. A.; Lee, C.-H.; Huang, S.-H.; Liu, C. W.

2014-03-01

Single electron spin states in silicon have shown a great deal of promise as qubits due to their long spin relaxation (T1) and coherence (T2) times. Recent results exhibit a T2 of 250 us for electrons confined in Si/SiGe quantum dots at 350 mK. These experiments used conventional X-band (10 GHz) pulsed Electron Spin Resonance on a large area (3.5 mm x 20 mm), dual-gated, undoped Si/SiGe heterostructure quantum dots. These dots are induced in a natural Si quantum well by e-beam defined gates having a lithographic radius of 150 nm and pitch of 700 nm. The relatively large size of these dots led to closely spaced energy levels and long T2's could only be measured at sub-Kelvin temperatures. At 2K confined electrons displayed a 3 us T2, which is comparable to that of 2D electrons at that temperature. Decreasing the quantum dot size increases the electron confinement and reduces the effects of valley-splitting and spin-orbit coupling on the electron spin coherence times. We will report results on dots with 80 nm lithographic radii and a 375 nm pitch. This device displays an extended electron coherence time of 30 us at 2K, suggesting tighter confinement of electrons. Further measurements at lower temperatures are in progress. This work was supported in part by NSF through the Materials World Network program (DMR-1107606) and the Princeton MRSEC (DMR-0819860), and in part by the U.S. Army Research Office (W911NF-13-1-0179).

Time-resolved measurements of coherent structures in the turbulent boundary layer

Science.gov (United States)

LeHew, J. A.; Guala, M.; McKeon, B. J.

2013-04-01

Time-resolved particle image velocimetry was used to examine the structure and evolution of swirling coherent structure (SCS), one interpretation of which is a marker for a three-dimensional coherent vortex structure, in wall-parallel planes of a turbulent boundary layer with a large field of view, 4.3 δ × 2.2 δ. Measurements were taken at four different wall-normal locations ranging from y/ δ = 0.08-0.48 at a friction Reynolds number, Re τ = 410. The data set yielded statistically converged results over a larger field of view than typically observed in the literature. The method for identifying and tracking swirling coherent structure is discussed, and the resulting trajectories, convection velocities, and lifespan of these structures are analyzed at each wall-normal location. The ability of a model in which the entirety of an individual SCS travels at a single convection velocity, consistent with the attached eddy hypothesis of Townsend (The structure of turbulent shear flows. Cambridge University Press, Cambridge, 1976), to describe the data is investigated. A methodology for determining whether such structures are "attached" or "detached" from the wall is also proposed and used to measure the lifespan and convection velocity distributions of these different structures. SCS were found to persist for longer periods of time further from the wall, particularly those inferred to be "detached" from the wall, which could be tracked for longer than 5 eddy turnover times.

On the estimation of wall pressure coherence using time-resolved tomographic PIV

Science.gov (United States)

Pröbsting, Stefan; Scarano, Fulvio; Bernardini, Matteo; Pirozzoli, Sergio

2013-07-01

Three-dimensional time-resolved velocity field measurements are obtained using a high-speed tomographic Particle Image Velocimetry (PIV) system on a fully developed flat plate turbulent boundary layer for the estimation of wall pressure fluctuations. The work focuses on the applicability of tomographic PIV to compute the coherence of pressure fluctuations, with attention to the estimation of the stream and spanwise coherence length. The latter is required for estimations of aeroacoustic noise radiation by boundary layers and trailing edge flows, but is also of interest for vibro-structural problems. The pressure field is obtained by solving the Poisson equation for incompressible flows, where the source terms are provided by time-resolved velocity field measurements. Measured 3D velocity data is compared to results obtained from planar PIV, and a Direct Numerical Simulation (DNS) at similar Reynolds number. An improved method for the estimation of the material based on a least squares estimator of the velocity derivative along a particle trajectory is proposed and applied. Computed surface pressure fluctuations are further verified by means of simultaneous measurements by a pinhole microphone and compared to the DNS results and a semi-empirical model available from literature. The correlation coefficient for the reconstructed pressure time series with respect to pinhole microphone measurements attains approximately 0.5 for the band-pass filtered signal over the range of frequencies resolved by the velocity field measurements. Scaled power spectra of the pressure at a single point compare favorably to the DNS results and those available from literature. Finally, the coherence of surface pressure fluctuations and the resulting span- and streamwise coherence lengths are estimated and compared to semi-empirical models and DNS results.

Real-time determination of the signal-to-noise ratio of partly coherent seismic time series

DEFF Research Database (Denmark)

Kjeldsen, Peter Møller

1994-01-01

it is of great practical interest to be able to monitor the S/N while the traces are recorded an approach for fast real-time determination of the S/N of seismic time series is proposed. The described method is based on an iterative procedure utilizing the trace-to-trace coherence, but unlike procedures known so...... far it uses calculated initial guesses and stop criterions. This significantly reduces the computational burden of the procedure so that real-time capabilities are obtained...

The in vivo study on the radiobiologic effect of prolonged delivery time to tumor control in C57BL mice implanted with Lewis lung cancer

International Nuclear Information System (INIS)

Wang, Xin; Xiong, Xiao-Peng; Lu, Jiade; Zhu, Guo-Pei; He, Shao-Qin; Hu, Chao-Su; Ying, Hong-Mei

2011-01-01

High-precision radiation therapy techniques such as IMRT or sterotactic radiosurgery, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The purpose of this work is to explore the radiobiologic effect of prolonged fraction delivery time on tumor response and survival in vivo. 1-cm-diameter Lewis lung cancer tumors growing in the legs of C57BL mice were used. To evaluate effect of dose delivery prolongation, 18 Gy was divided into different subfractions. 48 mice were randomized into 6 groups: the normal control group, the single fraction with 18 Gy group, the two subfractions with 30 min interval group, the seven subfractions with 5 min interval group, the two subfractions with 60 min interval group and the seven subfractions with 10 min interval group. The tumor growth tendency, the tumor growth delay and the mice survival time were analyzed. The tumor growth delay of groups with prolonged delivery time was shorter than the group with single fraction of 18 Gy (P < 0.05). The tumor grow delay of groups with prolonged delivery time 30 min was longer than that of groups with prolonged delivery time 60 min P < 0.05). There was no significant difference between groups with same delivery time (P > 0.05). Compared to the group with single fraction of 18 Gy, the groups with prolonged delivery time shorten the mice survival time while there was no significant difference between the groups with prolonged delivery time 30 min and the groups with prolonged delivery time 60 min. The prolonged delivery time with same radiation dose shorten the tumor growth delay and survival time in the mice implanted with Lewis lung cancer. The anti-tumor effect decreased with elongation of the total interfractional time

Linearity of Air-Biased Coherent Detection for Terahertz Time-Domain Spectroscopy

DEFF Research Database (Denmark)

Wang, Tianwu; Iwaszczuk, Krzysztof; Wrisberg, Emil Astrup

2016-01-01

The performance of air-biased coherent detection (ABCD) in a broadband two-color laser-induced air plasma system for terahertz time-domain spectroscopy (THz-TDS) has been investigated. Fundamental parameters of the ABCD detection, including signal-to-noise ratio (SNR), dynamic range (DR), and lin...

Coherence resonance in an excitable system with time delay

International Nuclear Information System (INIS)

Sethia, Gautam C.; Kurths, Juergen; Sen, Abhijit

2007-01-01

We study the noise activated dynamics of a model excitable system that consists of a subcritical Hopf oscillator with a time delayed nonlinear feedback. The coherence of the noise driven pulses of the system exhibits a novel double peaked structure as a function of the noise amplitude. The two peaks correspond to separate optimal noise levels for excitation of single spikes and multiple spikes (bursts) respectively. The relative magnitudes of these peaks are found to be a sensitive function of time delay. The physical significance of our results and its practical implications in various real life systems are discussed

Predicting time on prolonged benefits for injured workers with acute back pain.

Science.gov (United States)

Steenstra, Ivan A; Busse, Jason W; Tolusso, David; Davilmar, Arold; Lee, Hyunmi; Furlan, Andrea D; Amick, Ben; Hogg-Johnson, Sheilah

2015-06-01

Some workers with work-related compensated back pain (BP) experience a troubling course of disability. Factors associated with delayed recovery among workers with work-related compensated BP were explored. This is a cohort study of workers with compensated BP in 2005 in Ontario, Canada. Follow up was 2 years. Data was collected from employers, employees and health-care providers by the Workplace Safety and Insurance Board (WSIB). Exclusion criteria were: (1) no-lost-time claims, (2) >30 days between injury and claim filing, (3) benefits duration, and (4) age >65 years. Using proportional hazard models, we examined the prognostic value of information collected in the first 4 weeks after injury. Outcome measures were time on benefits during the first episode and time until recurrence after the first episode. Of 6,657 workers, 1,442 were still on full benefits after 4 weeks. Our final model containing age, physical demands, opioid prescription, union membership, availability of a return-to-work program, employer doubt about work-relatedness of injury, worker's recovery expectations, participation in a rehabilitation program and communication of functional ability was able to identify prolonged claims to a fair degree [area under the curve (AUC) = .79, 95% confidence interval (CI) .74-.84]. A model containing age, sex, physical demands, opioid prescription and communication of functional ability was less successful at predicting time until recurrence (AUC = .61, 95% CI .57, .65). Factors contained in information currently collected by the WSIB during the first 4 weeks on benefits can predict prolonged claims, but not recurrent claims.

Sub-Riemannian geometry and time optimal control of three spin systems: Quantum gates and coherence transfer

International Nuclear Information System (INIS)

Khaneja, Navin; Brockett, Roger; Glaser, Steffen J.

2002-01-01

Radio-frequency pulses are used in nuclear-magnetic-resonance spectroscopy to produce unitary transfer of states. Pulse sequences that accomplish a desired transfer should be as short as possible in order to minimize the effects of relaxation, and to optimize the sensitivity of the experiments. Many coherence-transfer experiments in NMR, involving a network of coupled spins, use temporary spin decoupling to produce desired effective Hamiltonians. In this paper, we demonstrate that significant time can be saved in producing an effective Hamiltonian if spin decoupling is avoided. We provide time-optimal pulse sequences for producing an important class of effective Hamiltonians in three-spin networks. These effective Hamiltonians are useful for coherence-transfer experiments in three-spin systems and implementation of indirect swap and Λ 2 (U) gates in the context of NMR quantum computing. It is shown that computing these time-optimal pulses can be reduced to geometric problems that involve computing sub-Riemannian geodesics. Using these geometric ideas, explicit expressions for the minimum time required for producing these effective Hamiltonians, transfer of coherence, and implementation of indirect swap gates, in a three-spin network are derived (Theorems 1 and 2). It is demonstrated that geometric control techniques provide a systematic way of finding time-optimal pulse sequences for transferring coherence and synthesizing unitary transformations in quantum networks, with considerable time savings (e.g., 42.3% for constructing indirect swap gates)

Impact of Azithromycin on Pregnancy Prolongation in Women at Risk of Preterm Labor: A Time-to-Event Analysis.

Science.gov (United States)

Goyer, Isabelle; Ferland, Gabrielle; Ruo, Ni; Morin, Caroline; Brochet, Marie-Sophie; Morin, Lucie; Ferreira, Ema

2016-09-13

Since 2006, the empiric use of azithromycin in women at risk of premature birth has become prevalent in our institution without any evidence of its efficacy. Although antibiotics can prolong pregnancy in preterm prolonged rupture of membranes, no published data are available for women with intact membranes. To describe the purpose of adding azithromycin to the usual treatments (cerclage, tocolysis, rest, etc.) to prolong pregnancy in women with intact membranes who are at risk of or already in preterm labour. A retrospective observational cohort study was done at a Mother-Child University Hospital Centre. Patients admitted to obstetric ward who received azithromycin between January 1 st , 2006 and August 1 st , 2010 were included. A total of 127 exposed women were matched to 127 controls through medical records and pharmacy software. A time-to-event analysis was done to compare gestational age at the time of the recorded composite event (delivery, or rupture of membranes, or second intervention to prolong pregnancy). To compare proportions of composite event at different time points, χ 2 tests were used. Patients who received azithromycin had a more severe condition at presentation. Once adjusted for confounding factors, prolongation of pregnancy (HR =1.049; CI 95%: 0.774-1.421 [p=0.758]) and gestational age at the event (HR=1.200; CI 95%: 0.894-1.609 [p=0.225]) did not differ between the groups. The proportions of women with an event ≥7 days post-diagnosis or ≥37 gestational weeks were similar. Azithromycin was added to medical therapy in a more at-risk population and no clear benefit was measured.

Femtosecond time-resolved studies of coherent vibrational Raman scattering in large gas-phase molecules

International Nuclear Information System (INIS)

Hayden, C.C.; Chandler, D.W.

1995-01-01

Results are presented from femtosecond time-resolved coherent Raman experiments in which we excite and monitor vibrational coherence in gas-phase samples of benzene and 1,3,5-hexatriene. Different physical mechanisms for coherence decay are seen in these two molecules. In benzene, where the Raman polarizability is largely isotropic, the Q branch of the vibrational Raman spectrum is the primary feature excited. Molecules in different rotational states have different Q-branch transition frequencies due to vibration--rotation interaction. Thus, the macroscopic polarization that is observed in these experiments decays because it has many frequency components from molecules in different rotational states, and these frequency components go out of phase with each other. In 1,3,5-hexatriene, the Raman excitation produces molecules in a coherent superposition of rotational states, through (O, P, R, and S branch) transitions that are strong due to the large anisotropy of the Raman polarizability. The coherent superposition of rotational states corresponds to initially spatially oriented, vibrationally excited, molecules that are freely rotating. The rotation of molecules away from the initial orientation is primarily responsible for the coherence decay in this case. These experiments produce large (∼10% efficiency) Raman shifted signals with modest excitation pulse energies (10 μJ) demonstrating the feasibility of this approach for a variety of gas phase studies. copyright 1995 American Institute of Physics

Coherent hybrid electromagnetic field imaging

Science.gov (United States)

Cooke, Bradly J [Jemez Springs, NM; Guenther, David C [Los Alamos, NM

2008-08-26

An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

Progranulin inhibits platelet aggregation and prolongs bleeding time in rats.

Science.gov (United States)

Al-Yahya, A M; Al-Masri, A A; El Eter, E A; Hersi, A; Lateef, R; Mawlana, O

2018-05-01

Several adipokines secreted by adipose tissue have an anti-thrombotic and anti-atherosclerotic function. Recently identified adipokine progranulin was found to play a protective role in atherosclerosis. Bearing in mind the central role of platelets in inflammation and atherosclerosis, we aimed, in this study, to examine the effect of progranulin on platelet function and coagulation profile in rats. Healthy male albino Wistar rats weighing (250-300 g) were divided into 4 groups. Three groups were given increasing doses of progranulin (0.001 µg, 0.01 µg, and 0.1 µg) intraperitoneally, while the control group received phosphate-buffered saline (PBS). Bleeding time, prothrombin time, activated partial thromboplastin time and platelet aggregation responses to adenosine diphosphate and arachidonic acid were assessed. Administration of progranulin resulted in a significant inhibition of platelet aggregation in response to both adenosine diphosphate, and arachidonic acid. Bleeding time, prothrombin time and activated partial thromboplastin time were significantly prolonged in all groups that received progranulin, in particular, the 0.1 µg dose, in comparison to the control group. This preliminary data is first suggesting that the antiplatelet and anticoagulant action of progranulin could have a physiological protective function against thrombotic disorders associated with obesity and atherosclerosis. However, these results merit further exploration.

The in vivo study on the radiobiologic effect of prolonged delivery time to tumor control in C57BL mice implanted with Lewis lung cancer

Directory of Open Access Journals (Sweden)

Zhu Guo-Pei

2011-01-01

Full Text Available Abstract Background High-precision radiation therapy techniques such as IMRT or sterotactic radiosurgery, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The purpose of this work is to explore the radiobiologic effect of prolonged fraction delivery time on tumor response and survival in vivo. Methods 1-cm-diameter Lewis lung cancer tumors growing in the legs of C57BL mice were used. To evaluate effect of dose delivery prolongation, 18 Gy was divided into different subfractions. 48 mice were randomized into 6 groups: the normal control group, the single fraction with 18 Gy group, the two subfractions with 30 min interval group, the seven subfractions with 5 min interval group, the two subfractions with 60 min interval group and the seven subfractions with 10 min interval group. The tumor growth tendency, the tumor growth delay and the mice survival time were analyzed. Results The tumor growth delay of groups with prolonged delivery time was shorter than the group with single fraction of 18 Gy (P 0.05. Compared to the group with single fraction of 18 Gy, the groups with prolonged delivery time shorten the mice survival time while there was no significant difference between the groups with prolonged delivery time 30 min and the groups with prolonged delivery time 60 min. Conclusions The prolonged delivery time with same radiation dose shorten the tumor growth delay and survival time in the mice implanted with Lewis lung cancer. The anti-tumor effect decreased with elongation of the total interfractional time.

Effect of prolonged gelling time on the intrinsic properties of barium alginate microcapsules and its biocompatibility.

Science.gov (United States)

Vaithilingam, Vijayaganapathy; Kollarikova, Gabriella; Qi, Meirigeng; Lacik, Igor; Oberholzer, Jose; Guillemin, Gilles J; Tuch, Bernard E

2011-01-01

Pericapsular fibrotic overgrowth (PFO) may be attributed to an immune response against microcapsules themselves or to antigen shedding through microcapsule pores from encapsulated islet tissue. Modification of microcapsules aimed at reducing pore size should prevent PFO and improve graft survival. This study investigated the effect of increased gelling time (20 vs. 2 min) in barium chloride on intrinsic properties of alginate microcapsules and tested their biocompatibility in vivo. Prolonged gelling time affected neither permeability nor size of the microcapsules. However, prolonged gelling time for 20 min produced brittle microcapsules compared to 2 min during compression test. Encapsulation of human islets in both types of microcapsules affected neither islet viability nor function. The presence of PFO when transplanted into a large animal model such as baboon and its absence in small animal models such as rodents suggest that the host immune response towards alginate microcapsules is species rather than alginate specific.

9. Nuclear power plant service life prolongation

International Nuclear Information System (INIS)

Evropin, S.V.

1998-01-01

The problem of prolongation of nuclear power plant service life duration is discussed. A schematic diagram of the program developed in the course of activities dealing with NPP service time prolongation is shown and analyzed in details. It is shown that the basic moment when determining the strategy for NPP service time prolongation is the positive confirmation of the agreement between the NPP safety provisions and modern safety requirements. The other very important aspect of the problem is engineering substantiation of the measures assuring the reactor operation prolongation. The conclusion is made that available methods of recovering reactor materials properties, main components repair and replacement, the modern techniques for nondestructive testing of metals and NPP pipelines, as well as the developed approaches to reactor facility safety improvements make the prolongation of the Russian NPP service lifetimes possible from engineering viewpoint and economically desirable

Brains striving for coherence: Long-term cumulative plot formation in the default mode network.

Science.gov (United States)

Tylén, K; Christensen, P; Roepstorff, A; Lund, T; Østergaard, S; Donald, M

2015-11-01

Many everyday activities, such as engaging in conversation or listening to a story, require us to sustain attention over a prolonged period of time while integrating and synthesizing complex episodic content into a coherent mental model. Humans are remarkably capable of navigating and keeping track of all the parallel social activities of everyday life even when confronted with interruptions or changes in the environment. However, the underlying cognitive and neurocognitive mechanisms of such long-term integration and profiling of information remain a challenge to neuroscience. While brain activity is generally traceable within the short time frame of working memory (milliseconds to seconds), these integrative processes last for minutes, hours or even days. Here we report two experiments on story comprehension. Experiment I establishes a cognitive dissociation between our comprehension of plot and incidental facts in narratives: when episodic material allows for long-term integration in a coherent plot, we recall fewer factual details. However, when plot formation is challenged, we pay more attention to incidental facts. Experiment II investigates the neural underpinnings of plot formation. Results suggest a central role for the brain's default mode network related to comprehension of coherent narratives while incoherent episodes rather activate the frontoparietal control network. Moreover, an analysis of cortical activity as a function of the cumulative integration of narrative material into a coherent story reveals to linear modulations of right hemisphere posterior temporal and parietal regions. Together these findings point to key neural mechanisms involved in the fundamental human capacity for cumulative plot formation. Copyright © 2015 Elsevier Inc. All rights reserved.

Photodetection-induced relative timing jitter in synchronized time-lens source for coherent Raman scattering microscopy

Directory of Open Access Journals (Sweden)

Jiaqi Wang

2017-09-01

Full Text Available Synchronized time-lens source is a novel method to generate synchronized optical pulses to mode-locked lasers, and has found widespread applications in coherent Raman scattering microscopy. Relative timing jitter between the mode-locked laser and the synchronized time-lens source is a key parameter for evaluating the synchronization performance of such synchronized laser systems. However, the origins of the relative timing jitter in such systems are not fully determined, which in turn prevents the experimental efforts to optimize the synchronization performance. Here, we demonstrate, through theoretical modeling and numerical simulation, that the photodetection could be one physical origin of the relative timing jitter. Comparison with relative timing jitter due to the intrinsic timing jitter of the mode-locked laser is also demonstrated, revealing different qualitative and quantitative behaviors. Based on the nature of this photodetection-induced timing jitter, we further propose several strategies to reduce the relative timing jitter. Our theoretical results will provide guidelines for optimizing synchronization performance in experiments.

Coherence-generating power of quantum dephasing processes

Science.gov (United States)

Styliaris, Georgios; Campos Venuti, Lorenzo; Zanardi, Paolo

2018-03-01

We provide a quantification of the capability of various quantum dephasing processes to generate coherence out of incoherent states. The measures defined, admitting computable expressions for any finite Hilbert-space dimension, are based on probabilistic averages and arise naturally from the viewpoint of coherence as a resource. We investigate how the capability of a dephasing process (e.g., a nonselective orthogonal measurement) to generate coherence depends on the relevant bases of the Hilbert space over which coherence is quantified and the dephasing process occurs, respectively. We extend our analysis to include those Lindblad time evolutions which, in the infinite-time limit, dephase the system under consideration and calculate their coherence-generating power as a function of time. We further identify specific families of such time evolutions that, although dephasing, have optimal (over all quantum processes) coherence-generating power for some intermediate time. Finally, we investigate the coherence-generating capability of random dephasing channels.

Prolonged sedentary time and physical activity in workplace and non-work contexts: a cross-sectional study of office, customer service and call centre employees.

Science.gov (United States)

Thorp, Alicia A; Healy, Genevieve N; Winkler, Elisabeth; Clark, Bronwyn K; Gardiner, Paul A; Owen, Neville; Dunstan, David W

2012-10-26

To examine sedentary time, prolonged sedentary bouts and physical activity in Australian employees from different workplace settings, within work and non-work contexts. A convenience sample of 193 employees working in offices (131), call centres (36) and customer service (26) was recruited. Actigraph GT1M accelerometers were used to derive percentages of time spent sedentary (customer service workers were typically the least sedentary and the most active at work. The workplace is a key setting for prolonged sedentary time, especially for some occupational groups, and the potential health risk burden attached requires investigation. Future workplace regulations and health promotion initiatives for sedentary occupations to reduce prolonged sitting time should be considered.

Oscillatory dynamics of vasoconstriction and vasodilation identified by time-localized phase coherence

International Nuclear Information System (INIS)

Sheppard, L W; McClintock, P V E; Stefanovska, A; Vuksanovic, V

2011-01-01

We apply wavelet-based time-localized phase coherence to investigate the relationship between blood flow and skin temperature, and between blood flow and instantaneous heart rate (IHR), during vasoconstriction and vasodilation provoked by local cooling or heating of the skin. A temperature-controlled metal plate (∼10 cm 2 ) placed on the volar side of the left arm was used to provide the heating and cooling. Beneath the plate, the blood flow was measured by laser Doppler flowmetry and the adjacent skin temperature by a thermistor. Two 1 h datasets were collected from each of the ten subjects. In each case a 30 min basal recording was followed by a step change in plate temperature, to either 24 deg. C or 42 deg. C. The IHR was derived from simultaneously recorded ECG. We confirm the changes in the energy and frequency of blood flow oscillations during cooling and heating reported earlier. That is, during cooling, there was a significant decrease in the average frequency of myogenic blood flow oscillations (p < 0.05) and the myogenic spectral peak became more prominent. During heating, there was a significant (p < 0.05) general increase in spectral energy, associated with vasodilation, except in the myogenic interval. Weak phase coherence between temperature and blood flow was observed for unperturbed skin, but it increased in all frequency intervals as a result of heating. It was not significantly affected by cooling. We also show that significant (p < 0.05) phase coherence exists between blood flow and IHR in the respiratory and myogenic frequency intervals. Cooling did not affect this phase coherence in any of the frequency intervals, whereas heating enhanced the phase coherence in the respiratory and myogenic intervals. This can be explained by the reduction in vascular resistance produced by heating, a process where myogenic mechanisms play a key role. We conclude that the mechanisms of vasodilation and vasoconstriction, in response to temperature change, are

Time series analysis of continuous-wave coherent Doppler Lidar wind measurements

International Nuclear Information System (INIS)

Sjoeholm, M; Mikkelsen, T; Mann, J; Enevoldsen, K; Courtney, M

2008-01-01

The influence of spatial volume averaging of a focused 1.55 μm continuous-wave coherent Doppler Lidar on observed wind turbulence measured in the atmospheric surface layer over homogeneous terrain is described and analysed. Comparison of Lidar-measured turbulent spectra with spectra simultaneously obtained from a mast-mounted sonic anemometer at 78 meters height at the test station for large wind turbines at Hoevsoere in Western Jutland, Denmark is presented for the first time

Digital coherent detection research on Brillouin optical time domain reflectometry with simplex pulse codes

International Nuclear Information System (INIS)

Hao Yun-Qi; Ye Qing; Pan Zheng-Qing; Cai Hai-Wen; Qu Rong-Hui

2014-01-01

The digital coherent detection technique has been investigated without any frequency-scanning device in the Brillouin optical time domain reflectometry (BOTDR), where the simplex pulse codes are applied in the sensing system. The time domain signal of every code sequence is collected by the data acquisition card (DAQ). A shift-averaging technique is applied in the frequency domain for the reason that the local oscillator (LO) in the coherent detection is fix-frequency deviated from the primary source. With the 31-bit simplex code, the signal-to-noise ratio (SNR) has 3.5-dB enhancement with the same single pulse traces, accordant with the theoretical analysis. The frequency fluctuation for simplex codes is 14.01 MHz less than that for a single pulse as to 4-m spatial resolution. The results are believed to be beneficial for the BOTDR performance improvement. (general)

Partially coherent isodiffracting pulsed beams

Science.gov (United States)

Koivurova, Matias; Ding, Chaoliang; Turunen, Jari; Pan, Liuzhan

2018-02-01

We investigate a class of isodiffracting pulsed beams, which are superpositions of transverse modes supported by spherical-mirror laser resonators. By employing modal weights that, for stationary light, produce a Gaussian Schell-model beam, we extend this standard model to pulsed beams. We first construct the two-frequency cross-spectral density function that characterizes the spatial coherence in the space-frequency domain. By assuming a power-exponential spectral profile, we then employ the generalized Wiener-Khintchine theorem for nonstationary light to derive the two-time mutual coherence function that describes the space-time coherence of the ensuing beams. The isodiffracting nature of the laser resonator modes permits all (paraxial-domain) calculations at any propagation distance to be performed analytically. Significant spatiotemporal coupling is revealed in subcycle, single-cycle, and few-cycle domains, where the partial spatial coherence also leads to reduced temporal coherence even though full spectral coherence is assumed.

An Application of the Coherent Noise Model for the Prediction of Aftershock Magnitude Time Series

Directory of Open Access Journals (Sweden)

Stavros-Richard G. Christopoulos

2017-01-01

Full Text Available Recently, the study of the coherent noise model has led to a simple (binary prediction algorithm for the forthcoming earthquake magnitude in aftershock sequences. This algorithm is based on the concept of natural time and exploits the complexity exhibited by the coherent noise model. Here, using the relocated catalogue from Southern California Seismic Network for 1981 to June 2011, we evaluate the application of this algorithm for the aftershocks of strong earthquakes of magnitude M≥6. The study is also extended by using the Global Centroid Moment Tensor Project catalogue to the case of the six strongest earthquakes in the Earth during the last almost forty years. The predictor time series exhibits the ubiquitous 1/f noise behavior.

Developing community based rehabilitation for cancer survivors: Organizing for coordination and coherence in practice

DEFF Research Database (Denmark)

la Cour, Karen; Cutchin, Malcolm

2013-01-01

Background. Increasing incidence of cancer combined with prolonged survival have raised the need for developing community based rehabilitation. The objectives of the analysis were to describe and interpret the key issues related to coordination and coherence of community-based cancer rehabilitation......-based organization, and informal relationships were fundamental for developing coordination and coherence. Conclusions. Coordination and coherence in community-based rehabilitation relies on increased collaboration, which may best be optimized by use of shared frameworks within and across systems. Results highlight...... in Denmark and to provide insights relevant for other contexts. Methods. Twenty-seven rehabilitation managers across 15 municipalities in Denmark comprised the sample. The study was designed with a combination of data collection methods including questionnaires, individual interviews, and focus groups...

Long-lived coherence in carotenoids

Energy Technology Data Exchange (ETDEWEB)

Davis, J A; Cannon, E; Van Dao, L; Hannaford, P [ARC Centre of Excellence for Coherent X-ray Science, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Victoria 3122 (Australia); Quiney, H M; Nugent, K A, E-mail: jdavis@swin.edu.a [ARC Centre of Excellence for Coherent X-ray Science, School of Physics, University of Melbourne, Victoria 3010 (Australia)

2010-08-15

We use two-colour vibronic coherence spectroscopy to observe long-lived vibrational coherences in the ground electronic state of carotenoid molecules, with decoherence times in excess of 1 ps. Lycopene and spheroidene were studied isolated in solution, and within the LH2 light-harvesting complex extracted from purple bacteria. The vibrational coherence time is shown to increase significantly for the carotenoid in the complex, providing further support to previous assertions that long-lived electronic coherences in light-harvesting complexes are facilitated by in-phase motion of the chromophores and surrounding proteins. Using this technique, we are also able to follow the evolution of excited state coherences and find that for carotenoids in the light-harvesting complex the (S{sub 2}|S{sub 0}) superposition remains coherent for more than 70 fs. In addition to the implications of this long electronic decoherence time, the extended coherence allows us to observe the evolution of the excited state wavepacket. These experiments reveal an enhancement of the vibronic coupling to the first vibrational level of the C-C stretching mode and/or methyl-rocking mode in the ground electronic state 70 fs after the initial excitation. These observations open the door to future experiments and modelling that may be able to resolve the relaxation dynamics of carotenoids in solution and in natural light-harvesting systems.

Long-lived coherence in carotenoids

International Nuclear Information System (INIS)

Davis, J A; Cannon, E; Van Dao, L; Hannaford, P; Quiney, H M; Nugent, K A

2010-01-01

We use two-colour vibronic coherence spectroscopy to observe long-lived vibrational coherences in the ground electronic state of carotenoid molecules, with decoherence times in excess of 1 ps. Lycopene and spheroidene were studied isolated in solution, and within the LH2 light-harvesting complex extracted from purple bacteria. The vibrational coherence time is shown to increase significantly for the carotenoid in the complex, providing further support to previous assertions that long-lived electronic coherences in light-harvesting complexes are facilitated by in-phase motion of the chromophores and surrounding proteins. Using this technique, we are also able to follow the evolution of excited state coherences and find that for carotenoids in the light-harvesting complex the (S 2 |S 0 ) superposition remains coherent for more than 70 fs. In addition to the implications of this long electronic decoherence time, the extended coherence allows us to observe the evolution of the excited state wavepacket. These experiments reveal an enhancement of the vibronic coupling to the first vibrational level of the C-C stretching mode and/or methyl-rocking mode in the ground electronic state 70 fs after the initial excitation. These observations open the door to future experiments and modelling that may be able to resolve the relaxation dynamics of carotenoids in solution and in natural light-harvesting systems.

Ringer's lactate, but not hydroxyethyl starch, prolongs the food intolerance time after major abdominal surgery; an open-labelled clinical trial.

Science.gov (United States)

Li, Yuhong; He, Rui; Ying, Xiaojiang; Hahn, Robert G

2015-05-06

The infusion of large amounts of Ringer's lactate prolongs the functional gastrointestinal recovery time and increases the number of complications after open abdominal surgery. We performed an open-labelled clinical trial to determine whether hydroxyethyl starch or Ringer's lactate exerts these adverse effects when the surgery is performed by laparoscopy. Eighty-eight patients scheduled for major abdominal cancer surgery (83% by laparoscopy) received a first-line fluid treatment with 9 ml/kg of either 6% hydroxyethyl starch 130/0.4 (Voluven) or Ringer's lactate, just after induction of anaesthesia; this was followed by a second-line infusion with 12 ml/kg of either starch or Ringer's lactate over 1 hour. Further therapy was managed at the discretion of the attending anaesthetist. Outcome data consisted of postoperative gastrointestinal recovery time, complications and length of hospital stay. The order of the infusions had no impact on the outcome. Both the administration of ≥ 2 L of Ringer's lactate and the development of a surgical complication were associated with a longer time period of paralytic ileus and food intolerance (two-way ANOVA, P food intolerance time amounted to 2 days each. The infusion of ≥ 1 L of hydroxyethyl starch did not adversely affect gastrointestinal recovery. Ringer's lactate, but not hydroxyethyl starch, prolonged the gastrointestinal recovery time in patients undergoing laparoscopic cancer surgery. Surgical complications prolonged the hospital stay.

Identifying finite-time coherent sets from limited quantities of Lagrangian data

Energy Technology Data Exchange (ETDEWEB)

Williams, Matthew O. [Program in Applied and Computational Mathematics, Princeton University, New Jersey 08544 (United States); Rypina, Irina I. [Department of Physical Oceanography, Woods Hole Oceanographic Institute, Massachusetts 02543 (United States); Rowley, Clarence W. [Department of Mechanical and Aerospace Engineering, Princeton University, New Jersey 08544 (United States)

2015-08-15

A data-driven procedure for identifying the dominant transport barriers in a time-varying flow from limited quantities of Lagrangian data is presented. Our approach partitions state space into coherent pairs, which are sets of initial conditions chosen to minimize the number of trajectories that “leak” from one set to the other under the influence of a stochastic flow field during a pre-specified interval in time. In practice, this partition is computed by solving an optimization problem to obtain a pair of functions whose signs determine set membership. From prior experience with synthetic, “data rich” test problems, and conceptually related methods based on approximations of the Perron-Frobenius operator, we observe that the functions of interest typically appear to be smooth. We exploit this property by using the basis sets associated with spectral or “mesh-free” methods, and as a result, our approach has the potential to more accurately approximate these functions given a fixed amount of data. In practice, this could enable better approximations of the coherent pairs in problems with relatively limited quantities of Lagrangian data, which is usually the case with experimental geophysical data. We apply this method to three examples of increasing complexity: The first is the double gyre, the second is the Bickley Jet, and the third is data from numerically simulated drifters in the Sulu Sea.

Identifying finite-time coherent sets from limited quantities of Lagrangian data

International Nuclear Information System (INIS)

Williams, Matthew O.; Rypina, Irina I.; Rowley, Clarence W.

2015-01-01

A data-driven procedure for identifying the dominant transport barriers in a time-varying flow from limited quantities of Lagrangian data is presented. Our approach partitions state space into coherent pairs, which are sets of initial conditions chosen to minimize the number of trajectories that “leak” from one set to the other under the influence of a stochastic flow field during a pre-specified interval in time. In practice, this partition is computed by solving an optimization problem to obtain a pair of functions whose signs determine set membership. From prior experience with synthetic, “data rich” test problems, and conceptually related methods based on approximations of the Perron-Frobenius operator, we observe that the functions of interest typically appear to be smooth. We exploit this property by using the basis sets associated with spectral or “mesh-free” methods, and as a result, our approach has the potential to more accurately approximate these functions given a fixed amount of data. In practice, this could enable better approximations of the coherent pairs in problems with relatively limited quantities of Lagrangian data, which is usually the case with experimental geophysical data. We apply this method to three examples of increasing complexity: The first is the double gyre, the second is the Bickley Jet, and the third is data from numerically simulated drifters in the Sulu Sea

Identifying finite-time coherent sets from limited quantities of Lagrangian data.

Science.gov (United States)

Williams, Matthew O; Rypina, Irina I; Rowley, Clarence W

2015-08-01

A data-driven procedure for identifying the dominant transport barriers in a time-varying flow from limited quantities of Lagrangian data is presented. Our approach partitions state space into coherent pairs, which are sets of initial conditions chosen to minimize the number of trajectories that "leak" from one set to the other under the influence of a stochastic flow field during a pre-specified interval in time. In practice, this partition is computed by solving an optimization problem to obtain a pair of functions whose signs determine set membership. From prior experience with synthetic, "data rich" test problems, and conceptually related methods based on approximations of the Perron-Frobenius operator, we observe that the functions of interest typically appear to be smooth. We exploit this property by using the basis sets associated with spectral or "mesh-free" methods, and as a result, our approach has the potential to more accurately approximate these functions given a fixed amount of data. In practice, this could enable better approximations of the coherent pairs in problems with relatively limited quantities of Lagrangian data, which is usually the case with experimental geophysical data. We apply this method to three examples of increasing complexity: The first is the double gyre, the second is the Bickley Jet, and the third is data from numerically simulated drifters in the Sulu Sea.

Coherent Waves in Seismic Researches

Science.gov (United States)

Emanov, A.; Seleznev, V. S.

2013-05-01

Development of digital processing algorithms of seismic wave fields for the purpose of useful event picking to study environment and other objects is the basis for the establishment of new seismic techniques. In the submitted paper a fundamental property of seismic wave field coherence is used. The authors extended conception of coherence types of observed wave fields and devised a technique of coherent component selection from observed wave field. Time coherence and space coherence are widely known. In this paper conception "parameter coherence" has been added. The parameter by which wave field is coherent can be the most manifold. The reason is that the wave field is a multivariate process described by a set of parameters. Coherence in the first place means independence of linear connection in wave field of parameter. In seismic wave fields, recorded in confined space, in building-blocks and stratified mediums time coherent standing waves are formed. In prospecting seismology at observation systems with multiple overlapping head waves are coherent by parallel correlation course or, in other words, by one measurement on generalized plane of observation system. For detail prospecting seismology at observation systems with multiple overlapping on basis of coherence property by one measurement of area algorithms have been developed, permitting seismic records to be converted to head wave time sections which have neither reflected nor other types of waves. Conversion in time section is executed on any specified observation base. Energy storage of head waves relative to noise on basis of multiplicity of observation system is realized within area of head wave recording. Conversion on base below the area of wave tracking is performed with lack of signal/noise ratio relative to maximum of this ratio, fit to observation system. Construction of head wave time section and dynamic plots a basis of automatic processing have been developed, similar to CDP procedure in method of

Coherent Coupled Qubits for Quantum Annealing

Science.gov (United States)

Weber, Steven J.; Samach, Gabriel O.; Hover, David; Gustavsson, Simon; Kim, David K.; Melville, Alexander; Rosenberg, Danna; Sears, Adam P.; Yan, Fei; Yoder, Jonilyn L.; Oliver, William D.; Kerman, Andrew J.

2017-07-01

Quantum annealing is an optimization technique which potentially leverages quantum tunneling to enhance computational performance. Existing quantum annealers use superconducting flux qubits with short coherence times limited primarily by the use of large persistent currents Ip. Here, we examine an alternative approach using qubits with smaller Ip and longer coherence times. We demonstrate tunable coupling, a basic building block for quantum annealing, between two flux qubits with small (approximately 50-nA) persistent currents. Furthermore, we characterize qubit coherence as a function of coupler setting and investigate the effect of flux noise in the coupler loop on qubit coherence. Our results provide insight into the available design space for next-generation quantum annealers with improved coherence.

In vivo relaxation time measurements on a murine tumor model--prolongation of T1 after photodynamic therapy.

Science.gov (United States)

Liu, Y H; Hawk, R M; Ramaprasad, S

1995-01-01

RIF tumors implanted on mice feet were investigated for changes in relaxation times (T1 and T2) after photodynamic therapy (PDT). Photodynamic therapy was performed using Photofrin II as the photosensitizer and laser light at 630 nm. A home-built proton solenoid coil in the balanced configuration was used to accommodate the tumors, and the relaxation times were measured before, immediately after, and up to several hours after therapy. Several control experiments were performed untreated tumors, tumors treated with Photofrin II alone, or tumors treated with laser light alone. Significant increases in T1s of water protons were observed after PDT treatment. In all experiments, 31P spectra were recorded before and after the therapy to study the tumor status and to confirm the onset of PDT. These studies show significant prolongation of T1s after the PDT treatment. The spin-spin relaxation measurements, on the other hand, did not show such prolongation in T2 values after PDT treatment.

Store operations to maintain cache coherence

Energy Technology Data Exchange (ETDEWEB)

Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

2017-08-01

In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

Store operations to maintain cache coherence

Energy Technology Data Exchange (ETDEWEB)

Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

2017-09-12

In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

Time-variant coherence between heart rate variability and EEG activity in epileptic patients: an advanced coupling analysis between physiological networks

International Nuclear Information System (INIS)

Piper, D; Schiecke, K; Pester, B; Witte, H; Benninger, F; Feucht, M

2014-01-01

Time-variant coherence analysis between the heart rate variability (HRV) and the channel-related envelopes of adaptively selected EEG components was used as an indicator for the occurrence of (correlative) couplings between the central autonomic network (CAN) and the epileptic network before, during and after epileptic seizures. Two groups of patients were investigated, a group with left and a group with right hemispheric temporal lobe epilepsy. The individual EEG components were extracted by a signal-adaptive approach, the multivariate empirical mode decomposition, and the envelopes of each resulting intrinsic mode function (IMF) were computed by using Hilbert transform. Two IMFs, whose envelopes were strongly correlated with the HRV’s low-frequency oscillation (HRV-LF; ≈0.1 Hz) before and after the seizure were identified. The frequency ranges of these IMFs correspond to the EEG delta-band. The time-variant coherence was statistically quantified and tensor decomposition of the time-frequency coherence maps was applied to explore the topography-time-frequency characteristics of the coherence analysis. Results allow the hypothesis that couplings between the CAN, which controls the cardiovascular-cardiorespiratory system, and the ‘epileptic neural network’ exist. Additionally, our results confirm the hypothesis of a right hemispheric lateralization of sympathetic cardiac control of the HRV-LF. (paper)

Coherence time of over a second in a telecom-compatible quantum memory storage material

Science.gov (United States)

Rančić, Miloš; Hedges, Morgan P.; Ahlefeldt, Rose L.; Sellars, Matthew J.

2018-01-01

Quantum memories for light will be essential elements in future long-range quantum communication networks. These memories operate by reversibly mapping the quantum state of light onto the quantum transitions of a material system. For networks, the quantum coherence times of these transitions must be long compared to the network transmission times, approximately 100 ms for a global communication network. Due to a lack of a suitable storage material, a quantum memory that operates in the 1,550 nm optical fibre communication band with a storage time greater than 1 μs has not been demonstrated. Here we describe the spin dynamics of 167Er3+: Y2SiO5 in a high magnetic field and demonstrate that this material has the characteristics for a practical quantum memory in the 1,550 nm communication band. We observe a hyperfine coherence time of 1.3 s. We also demonstrate efficient spin pumping of the entire ensemble into a single hyperfine state, a requirement for broadband spin-wave storage. With an absorption of 70 dB cm-1 at 1,538 nm and Λ transitions enabling spin-wave storage, this material is the first candidate identified for an efficient, broadband quantum memory at telecommunication wavelengths.

Real-time Optical Coherence Tomography Incorporated in the Operating Microscope during Cataract Surgery.

Science.gov (United States)

Almutlak, Mohammed A; Aloniazan, Turki; May, William

2017-01-01

A 55-year-old male presented with reduced vision due to senile cataract. The patient consented to undergo real-time intraoperative anterior segment-optical coherence tomography (AS-OCT) during phacoemulsification with intraocular lens (IOL) implantation. Images were captured at various points during the surgery. The use of AS-OCT incorporated into the surgical microscope was evaluated as an adjunct to cataract surgery. We were able to successfully evaluate, in real-time, wound architecture, the attachment of Descemet's membrane, the posterior capsule, and IOL position. Real-time AS-OCT can be used to proactively address potential complications and verify IOL placement intraoperatively.

Dependence of high density nitrogen-vacancy center ensemble coherence on electron irradiation doses and annealing time

Science.gov (United States)

Zhang, C.; Yuan, H.; Zhang, N.; Xu, L. X.; Li, B.; Cheng, G. D.; Wang, Y.; Gui, Q.; Fang, J. C.

2017-12-01

Negatively charged nitrogen-vacancy (NV-) center ensembles in diamond have proved to have great potential for use in highly sensitive, small-package solid-state quantum sensors. One way to improve sensitivity is to produce a high-density NV- center ensemble on a large scale with a long coherence lifetime. In this work, the NV- center ensemble is prepared in type-Ib diamond using high energy electron irradiation and annealing, and the transverse relaxation time of the ensemble—T 2—was systematically investigated as a function of the irradiation electron dose and annealing time. Dynamical decoupling sequences were used to characterize T 2. To overcome the problem of low signal-to-noise ratio in T 2 measurement, a coupled strip lines waveguide was used to synchronously manipulate NV- centers along three directions to improve fluorescence signal contrast. Finally, NV- center ensembles with a high concentration of roughly 1015 mm-3 were manipulated within a ~10 µs coherence time. By applying a multi-coupled strip-lines waveguide to improve the effective volume of the diamond, a sub-femtotesla sensitivity for AC field magnetometry can be achieved. The long-coherence high-density large-scale NV- center ensemble in diamond means that types of room-temperature micro-sized solid-state quantum sensors with ultra-high sensitivity can be further developed in the near future.

Nuclear energy as a 'golden bridge'? Constitutional legal problems of the negotiation of the prolongation of the running time against skimming of profits

International Nuclear Information System (INIS)

Waldhoff, Christian; Aswege, Hanka von

2010-01-01

The coalition agreement of Christian Demographic Union (CDU), Christian Social Union (CSU) and Free Democratic Party (FDP) from 26th October, 2009 characterizes the nuclear energy as a bridge technology. The coalition parties explain to prolong the running times of German nuclear power stations up to a reliable replacement by renewable energies. The conditions for the prolongation of the running times are to be regulated in agreement with energy supply companies. In the contribution under consideration, the authors report on the fiscal legal problems of the skimming of profits. Constitutional legal problems of the earmaking of a skimming of profits as well as a consensual agreement are discussed in this contribution. In the result, a financial constitutionally reliable way for the skimming of added profits due to prolongation of the running time is not evident. The legal earmaking of the duty advent for the promotion of renewable energies increases the constitutional doubts.

Optical Coherence Tomography

DEFF Research Database (Denmark)

Fercher, A.F.; Andersen, Peter E.

2017-01-01

Optical coherence tomography (OCT) is a technique that is used to peer inside a body noninvasively. Tissue structure defined by tissue absorption and scattering coefficients, and the speed of blood flow, are derived from the characteristics of light remitted by the body. Singly backscattered light...... detected by partial coherence interferometry (PCI) is used to synthesize the tomographic image coded in false colors. A prerequisite of this technique is a low time-coherent but high space-coherent light source, for example, a superluminescent diode or a supercontinuum source. Alternatively, the imaging...... technique can be realized by using ultrafast wavelength scanning light sources. For tissue imaging, the light source wavelengths are restricted to the red and near-infrared (NIR) region from about 600 to 1300 nm, the so-called therapeutic window, where absorption (μa ≈ 0.01 mm−1) is small enough. Transverse...

Coherent systems with multistate components

International Nuclear Information System (INIS)

Caldarola, L.

1980-01-01

The basic rules of the Boolean algebra with restrictions on variables are briefly recalled. This special type of Boolean algebra allows one to handle fault trees of systems made of multistate (two or more than two states) components. Coherent systems are defined in the case of multistate components. This definition is consistent with that originally suggested by Barlow in the case of binary (two states) components. The basic properties of coherence are described and discussed. Coherent Boolean functions are also defined. It is shown that these functions are irredundant, that is they have only one base which is at the same time complete and irredundant. However, irredundant functions are not necessarily coherent. Finally a simplified algorithm for the calculation of the base of a coherent function is described. In the case that the function is not coherent, the algorithm can be used to reduce the size of the normal disjunctive form of the function. This in turn eases the application of the Nelson algorithm to calculate the complete base of the function. The simplified algorithm has been built in the computer program MUSTAFA-1. In a sample case the use of this algorithm caused a reduction of the CPU time by a factor of about 20. (orig.)

Parental Internet Use and Lifestyle Factors as Correlates of Prolonged Screen Time of Children in Japan: Results From the Super Shokuiku School Project.

Science.gov (United States)

Yamada, Masaaki; Sekine, Michikazu; Tatsuse, Takashi

2018-03-24

Prolonged screen time (ST), which includes TV viewing and gaming on smartphones and computers, is linked to poor health. Our aim was to explore the associations between school children with prolonged ST and parental internet use (IU) and lifestyles in Japan. Children aged 6 to 13 years from the Super Shokuiku School Project, were surveyed using questionnaires in 2016. The survey assessed the grade, sex, and lifestyle of 1,659 children and parental internet use (IU) and lifestyle using Breslow's seven health behaviors. IU consisted of internet surfing and gaming on personal computers (PC), smartphones, or consoles. Three or more hours of ST was defined as prolonged ST, and its correlates were analyzed using logistic regression. Of all, 643 (38.8%) children spent ≥2 hours/day of ST on a week day, whilst 153 (9.2%) children spent ≥3 hours/day. Prolonged ST was significantly associated with children in higher grade (odds ratio [OR] 1.74; 95% confidence interval [CI], 1.20-2.51), boys (OR 2.16; 95% CI, 1.49-3.14), skipping breakfast (OR 1.88; 95% CI, 1.05-3.35), late bedtime (OR 1.80; 95% CI, 1.15-2.82), physical inactivity (OR 1.79; 95% CI, 1.12-2.87), father's IU ≥2 hours/day (OR 2.35; 95% CI, 1.52-3.63), mother's prolonged IU ≥2 hours/day (OR 2.55; 95% CI, 1.43-4.52), mothers with unhealthy behaviors (OR 1.81; 95% CI, 1.05-3.13), no rule setting governing screen time (OR 2.41; 95% CI, 1.63-3.58), and mothers with full-time employment (OR 1.95; 95% CI, 1.06-3.64). Prolonged ST among Japanese children was strongly associated with parental IU, no set rules for ST, and mother's unhealthy lifestyles. To reduce children's ST, parental engagement is warranted in the intervention strategy.

Coherent Raman scattering: Applications in imaging and sensing

Science.gov (United States)

Cui, Meng

In this thesis, I discuss the theory, implementation and applications of coherent Raman scattering to imaging and sensing. A time domain interferometric method has been developed to collect high resolution shot-noise-limited Raman spectra over the Raman fingerprint regime and completely remove the electronic background signal in coherent Raman scattering. Compared with other existing coherent Raman microscopy methods, this time domain approach is proved to be simpler and more robust in rejecting background signal. We apply this method to image polymers and biological samples and demonstrate that the same setup can be used to collect two photon fluorescence and self phase modulation signals. A signal to noise ratio analysis is performed to show that this time domain method has a comparable signal to noise ratio to spectral domain methods, which we confirm experimentally. The coherent Raman method is also compared with spontaneous Raman scattering. The conditions under which coherent methods provide signal enhancement are discussed and experiments are performed to compare coherent Raman scattering with spontaneous Raman scattering under typical biological imaging conditions. A critical power, above which coherent Raman scattering is more sensitive than spontaneous Raman scattering, is experimentally determined to be ˜1mW in samples of high molecule concentration with a 75MHz laser system. This finding is contrary to claims that coherent methods provide many orders of magnitude enhancement under comparable conditions. In addition to the far field applications, I also discuss the combination of our time domain coherent Raman method with near field enhancement to explore the possibility of sensing and near field imaging. We report the first direct time-resolved coherent Raman measurement performed on a nanostructured substrate for molecule sensing. The preliminary results demonstrate that sub 20 fs pulses can be used to obtain coherent Raman spectra from a small number

Position-dependent radiative transfer as a tool for studying Anderson localization: Delay time, time-reversal and coherent backscattering

Science.gov (United States)

van Tiggelen, B. A.; Skipetrov, S. E.; Page, J. H.

2017-05-01

Previous work has established that the localized regime of wave transport in open media is characterized by a position-dependent diffusion coefficient. In this work we study how the concept of position-dependent diffusion affects the delay time, the transverse confinement, the coherent backscattering, and the time reversal of waves. Definitions of energy transport velocity of localized waves are proposed. We start with a phenomenological model of radiative transfer and then present a novel perturbational approach based on the self-consistent theory of localization. The latter allows us to obtain results relevant for realistic experiments in disordered quasi-1D wave guides and 3D slabs.

Real-time three-dimensional imaging of epidermal splitting and removal by high-definition optical coherence tomography

DEFF Research Database (Denmark)

Boone, Marc; Draye, Jean Pierre; Verween, Gunther

2014-01-01

While real-time 3-D evaluation of human skin constructs is needed, only 2-D non-invasive imaging techniques are available. The aim of this paper is to evaluate the potential of high-definition optical coherence tomography (HD-OCT) for real-time 3-D assessment of the epidermal splitting and decell......While real-time 3-D evaluation of human skin constructs is needed, only 2-D non-invasive imaging techniques are available. The aim of this paper is to evaluate the potential of high-definition optical coherence tomography (HD-OCT) for real-time 3-D assessment of the epidermal splitting...... before and after incubation. Real-time 3-D HD-OCT assessment was compared with 2-D en face assessment by reflectance confocal microscopy (RCM). (Immuno) histopathology was used as control. HD-OCT imaging allowed real-time 3-D visualization of the impact of selected agents on epidermal splitting, dermo......-epidermal junction, dermal architecture, vascular spaces and cellularity. RCM has a better resolution (1 μm) than HD-OCT (3 μm), permitting differentiation of different collagen fibres, but HD-OCT imaging has deeper penetration (570 μm) than RCM imaging (200 μm). Dispase II and NaCl treatments were found...

Coherent control of photoelectron wavepacket angular interferograms

International Nuclear Information System (INIS)

Hockett, P; Wollenhaupt, M; Baumert, T

2015-01-01

Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process, where the final (time-integrated) observable coherently samples all instantaneous states of the light–matter interaction. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable. (paper)

Coherent control of photoelectron wavepacket angular interferograms

Science.gov (United States)

Hockett, P.; Wollenhaupt, M.; Baumert, T.

2015-11-01

Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process, where the final (time-integrated) observable coherently samples all instantaneous states of the light-matter interaction. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.

Coherence-based Time Series Clustering for Brain Connectivity Visualization

KAUST Repository

Euan, Carolina

2017-11-19

We develop the hierarchical cluster coherence (HCC) method for brain signals, a procedure for characterizing connectivity in a network by clustering nodes or groups of channels that display high level of coordination as measured by

Coherence-based Time Series Clustering for Brain Connectivity Visualization

KAUST Repository

Euan, Carolina; Sun, Ying; Ombao, Hernando

2017-01-01

We develop the hierarchical cluster coherence (HCC) method for brain signals, a procedure for characterizing connectivity in a network by clustering nodes or groups of channels that display high level of coordination as measured by

Theory of coherent resonance energy transfer

International Nuclear Information System (INIS)

Jang, Seogjoo; Cheng, Y.-C.; Reichman, David R.; Eaves, Joel D.

2008-01-01

A theory of coherent resonance energy transfer is developed combining the polaron transformation and a time-local quantum master equation formulation, which is valid for arbitrary spectral densities including common modes. The theory contains inhomogeneous terms accounting for nonequilibrium initial preparation effects and elucidates how quantum coherence and nonequilibrium effects manifest themselves in the coherent energy transfer dynamics beyond the weak resonance coupling limit of the Foerster and Dexter (FD) theory. Numerical tests show that quantum coherence can cause significant changes in steady state donor/acceptor populations from those predicted by the FD theory and illustrate delicate cooperation of nonequilibrium and quantum coherence effects on the transient population dynamics.

Photonic compressive sensing enabled data efficient time stretch optical coherence tomography

Science.gov (United States)

Mididoddi, Chaitanya K.; Wang, Chao

2018-03-01

Photonic time stretch (PTS) has enabled real time spectral domain optical coherence tomography (OCT). However, this method generates a torrent of massive data at GHz stream rate, which requires capturing as per Nyquist principle. If the OCT interferogram signal is sparse in Fourier domain, which is always true for samples with limited number of layers, it can be captured at lower (sub-Nyquist) acquisition rate as per compressive sensing method. In this work we report a data compressed PTS-OCT system based on photonic compressive sensing with 66% compression with low acquisition rate of 50MHz and measurement speed of 1.51MHz per depth profile. A new method has also been proposed to improve the system with all-optical random pattern generation, which completely avoids electronic bottleneck in traditional binary pseudorandom binary sequence (PRBS) generators.

Temperature Measurements in Reacting Flows Using Time-Resolved Femtosecond Coherent Anti-Stokes Raman Scattering (fs-CARS) Spectroscopy (Postprint)

National Research Council Canada - National Science Library

Roy, Sukesh; Kinnius, Paul J; Lucht, Robert P; Gord, James R

2007-01-01

Time-resolved femtosecond coherent anti-Stokes Raman scattering (fs-CARS) spectroscopy of the nitrogen molecule is used for the measurement of temperature in atmospheric-pressure, near-adiabatic, hydrogen-air diffusion flames...

Time series analysis of continuous-wave coherent Doppler Lidar wind measurements

DEFF Research Database (Denmark)

Sjöholm, Mikael; Mikkelsen, Torben; Mann, Jakob

2008-01-01

The influence of spatial volume averaging of a focused 1.55 mu m continuous-wave coherent Doppler Lidar on observed wind turbulence measured in the atmospheric surface layer over homogeneous terrain is described and analysed. Comparison of Lidar-measured turbulent spectra with spectra simultaneou......The influence of spatial volume averaging of a focused 1.55 mu m continuous-wave coherent Doppler Lidar on observed wind turbulence measured in the atmospheric surface layer over homogeneous terrain is described and analysed. Comparison of Lidar-measured turbulent spectra with spectra...

The analysis of false prolongation of the activated partial thromboplastin time (activator: silica): Interference of C-reactive protein.

Science.gov (United States)

Liu, Jie; Li, Fanfan; Shu, Kuangyi; Chen, Tao; Wang, Xiaoou; Xie, Yaoqi; Li, Shanshan; Zhang, Zhaohua; Jin, Susu; Jiang, Minghua

2018-05-13

To investigate the effect of C-reactive protein on the activated partial thromboplastin time (APTT) (different activators) in different detecting systems. The C-reactive protein and coagulation test of 112 patients with the infectious disease were determined by automation protein analyzer IMMAG 800 and automation coagulation analyzer STA-R Evolution, respectively. The pooled plasma APTT with different concentrations of C-reactive protein was measured by different detecting system: STA-R Evolution (activator: silica, kaolin), Sysmex CS-2000i (activator: ellagic acid), and ACL TOP 700 (activator: colloidal silica). In addition, the self-made platelet lysate (phospholipid) was added to correct the APTT prolonged by C-reactive protein (150 mg/L) on STA-R Evolution (activator: silica) system. The good correlation between C-reactive protein and APTT was found on the STA-R Evolution (activator: silica) system. The APTT on the STA-R Evolution (activator: silica) system was prolonged by 24.6 second, along with increasing C-reactive protein concentration. And the APTT of plasma containing 150 mg/L C-reactive protein was shortened by 3.4-6.9 second when the plasma was mixed with self-made platelet lysate. However, the APTT was prolonged unobviously on other detecting systems including STA-R Evolution (activator: kaolin), Sysmex CS-2000i, and ACL TOP 700. C-reactive protein interferes with the detection of APTT, especially in STA-R Evolution (activator: silica) system. The increasing in C-reactive protein results in a false prolongation of the APTT (activator: silica), and it is most likely that C-reactive protein interferes the coagulable factor binding of phospholipid. © 2018 Wiley Periodicals, Inc.

Characterisation of dispersive systems using a coherer

Directory of Open Access Journals (Sweden)

Nikolić Pantelija M.

2002-01-01

Full Text Available The possibility of characterization of aluminium powders using a horizontal coherer has been considered. Al powders of known dimension were treated with a high frequency electromagnetic field or with a DC electric field, which were increased until a dielectric breakdown occurred. Using a multifunctional card PC-428 Electronic Design and a suitable interface between the coherer and PC, the activation time of the coherer was measured as a function of powder dimension and the distance between the coherer electrodes. It was also shown that the average dimension of powders of unknown size could be determined using the coherer.

SAR image effects on coherence and coherence estimation.

Energy Technology Data Exchange (ETDEWEB)

Bickel, Douglas Lloyd

2014-01-01

Radar coherence is an important concept for imaging radar systems such as synthetic aperture radar (SAR). This document quantifies some of the effects in SAR which modify the coherence. Although these effects can disrupt the coherence within a single SAR image, this report will focus on the coherence between separate images, such as for coherent change detection (CCD) processing. There have been other presentations on aspects of this material in the past. The intent of this report is to bring various issues that affect the coherence together in a single report to support radar engineers in making decisions about these matters.

Prolonged unexplained fatigue in paediatrics

NARCIS (Netherlands)

Bakker, R.J.

2010-01-01

Prolonged Unexplained Fatigue in Paediatrics. Fatigue, as the result of mental or physical exertion, will disappear after rest, drinks and food. Fatigue as a symptom of illness will recover with the recovering of the illness. But when fatigue is ongoing for a long time, and not the result of

Anatomy of a digital coherent receiver

DEFF Research Database (Denmark)

Borkowski, Robert; Zibar, Darko; Tafur Monroy, Idelfonso

2014-01-01

, orthonormaliation, chromatic dispersion compensation/nonlinear compensation, resampling a nd timing recovery, polarization demultiplexing and equalization, frequency and phase recovery, digital demodulation. We also describe novel subsystems of a digital coherent receiver: modulation format recognition......Digital coherent receivers have gained significant attention in the last decade. The reason for this is that coherent detection, along with digital signal processing (DSP) allows for substantial increase of the channel capacity by employing advanced detection techniques. In this paper, we first...

Integrated coherent matter wave circuits

International Nuclear Information System (INIS)

Ryu, C.; Boshier, M. G.

2015-01-01

An integrated coherent matter wave circuit is a single device, analogous to an integrated optical circuit, in which coherent de Broglie waves are created and then launched into waveguides where they can be switched, divided, recombined, and detected as they propagate. Applications of such circuits include guided atom interferometers, atomtronic circuits, and precisely controlled delivery of atoms. We report experiments demonstrating integrated circuits for guided coherent matter waves. The circuit elements are created with the painted potential technique, a form of time-averaged optical dipole potential in which a rapidly moving, tightly focused laser beam exerts forces on atoms through their electric polarizability. Moreover, the source of coherent matter waves is a Bose-Einstein condensate (BEC). Finally, we launch BECs into painted waveguides that guide them around bends and form switches, phase coherent beamsplitters, and closed circuits. These are the basic elements that are needed to engineer arbitrarily complex matter wave circuitry

A method for characterization of coherent backgrounds in real time and its application in gravitational wave data analysis

International Nuclear Information System (INIS)

Daw, E J; Hewitson, M R

2008-01-01

Many experiments, and in particular gravitational wave detectors, produce continuous streams of data whose frequency representations contain discrete, relatively narrowband coherent features at high amplitude. We discuss the application of digital Fourier transforms (DFTs) to characterization of these features, hereafter frequently referred to as lines. Application of DFTs to continuously produced time-domain data is achieved through an algorithm, hereafter referred to as EFC , for efficient time-domain determination of the Fourier coefficients of a data set. We first define EFC and discuss parameters relating to the algorithm that determine its properties and action on the data. In gravitational wave interferometers, these lines are commonly due to parasitic sources of coherent background interference coupling into the instrument. Using GEO 600 data, we next demonstrate that time-domain subtraction of lines can proceed without detrimental effects either on features at frequencies separated from that of the subtracted line, or on features at the frequency of the line but having different stationarity properties

Prolonged response without prolonged chemotherapy: a lesson from PCV chemotherapy in low-grade gliomas

Science.gov (United States)

Peyre, Matthieu; Cartalat-Carel, Stéphanie; Meyronet, David; Ricard, Damien; Jouvet, Anne; Pallud, Johan; Mokhtari, Karima; Guyotat, Jacques; Jouanneau, Emmanuel; Sunyach, Marie-Pierre; Frappaz, Didier; Honnorat, Jérôme; Ducray, François

2010-01-01

Previous studies with temozolomide suggest that a prolonged duration of chemotherapy is important for treating low-grade gliomas (LGGs). PCV (procarbazine, CCNU, vincristine) chemotherapy has demonstrated efficacy in treating LGGs, but this therapy cannot be used for a prolonged period because of the cumulative toxicity. The aim of the present study was to evaluate the impact of first-line PCV chemotherapy on LGGs growth kinetics. The mean tumor diameter (MTD) of 21 LGGs was measured on serial magnetic resonance images before (n=13), during, and after PCV onset (n=21). During PCV treatment, a decrease in the MTD was observed in all patients. After PCV discontinuation, an ongoing decrease in MTD was observed in 20 of the 21 patients. Median duration of the MTD decrease was 3.4 years (range, 0.8–7.7) after PCV onset and 2.7 years (range, 0–7) after the end of PCV treatment with 60% of LGGs, demonstrating an ongoing and prolonged (>2 years) response despite chemotherapy no longer being administered. According to McDonald's criteria, the rates of partial and minor responses were 5% and 38% at the end of PCV but 38% and 42% at the time of maximal MTD decrease, which occurred after a median period of 3.4 years after PCV onset. These results challenge the idea that a prolonged duration of chemotherapy is necessary for treating LGGs and raise the issue of understanding the mechanisms involved in the persistent tumor volume decrease once chemotherapy is terminated. PMID:20488959

Saline Flush After Rocuronium Bolus Reduces Onset Time and Prolongs Duration of Effect: A Randomized Clinical Trial.

Science.gov (United States)

Ishigaki, Sayaka; Masui, Kenichi; Kazama, Tomiei

2016-03-01

Circulatory factors modify the onset time of neuromuscular-blocking drugs. Therefore, we hypothesized that infusion of a saline flush immediately after rocuronium administration would shorten the onset time without influencing the duration of the rocuronium effect. Forty-eight patients were randomly allocated to the control or saline flush group. Anesthesia was induced and maintained with propofol and remifentanil, and all patients received 0.6 mg/kg rocuronium in 10 mL of normal saline. In the saline flush group, 20 mL normal saline was immediately infused after rocuronium administration. Neuromuscular blockade was assessed using acceleromyography at the adductor pollicis muscle with train-of-four (TOF) stimulation. The neuromuscular indices for rocuronium were calculated as follows: the latent onset time, defined as the time from the start of rocuronium infusion until first occurrence of depression of the first twitch of the TOF (T1) ≥5%; onset time, defined as the time from the start of rocuronium infusion until first occurrence of depression of the T1 ≥95%; clinical duration, defined as the time from the start of rocuronium administration until T1 recovered to 25% of the final T1 value; recovery index, defined as the time for recovery of T1 from 25% to 75% of the final T1 value; and the total recovery time, defined as the time from the start of rocuronium administration until reaching a TOF ratio of 0.9. Significance was designated at P rocuronium bolus by 17%, 24%, and 14%, respectively. In addition, the recovery phase was significantly prolonged in the saline flush group. The mean clinical duration (5th-95th percentile range) in the saline flush group and control group was 35 minutes (27-63 minutes) and 31 minutes (19-48 minutes; P = 0.032), respectively; the recovery index was 13 minutes (8-25 minutes) and 10 minutes (7-19 minutes; P = 0.019), respectively; and the total recovery time was 61 minutes (44-108 minutes) and 50 minutes (35-93 minutes; P = 0

Prolonged sitting in cars: prevalence, socio-demographic variations, and trends.

Science.gov (United States)

Sugiyama, Takemi; Merom, Dafna; van der Ploeg, Hidde P; Corpuz, Grace; Bauman, Adrian; Owen, Neville

2012-10-01

Prolonged sitting is detrimentally associated with health outcomes. However, the prevalence and characteristics of those who sit in cars for long periods are not well understood. This study examined the population prevalence, socio-demographic variations, and trends for prolonged sitting in cars among adults. Using the Sydney Greater Metropolitan Area Household Travel Survey, the prevalence of prolonged sitting time in cars (≥2 h/day) was calculated for four 3-year periods (1997-99, 2000-02, 2003-05, and 2006-08) for each population subgroup. Trends were calculated as the mean change in prevalence between adjacent survey periods. Cars were used for 66% of the total trips recorded (n=336,505). The prevalence of prolonged sitting time in cars was 16-18% in men, and 10-12% in women. Relatively higher prevalence rates were found among middle-age groups (men: 20-22%, women: 12-15%), full-time workers (men: 21-24%, women: 14-15%), those with higher income (men: 21-25%, women: 14-16%), couples with children (men: 20-21%, women: 12-14%), and those living in outer suburbs (men: 20-23%, women: 12-13%). Trends were stable in men, but increasing in women. Several subgroups (older age; living in regional suburbs) also showed increasing trends. These findings provide evidence to inform integrated approaches to measurement and policy development on prolonged car use among the public health, urban planning, and transport sectors. Copyright © 2012 Elsevier Inc. All rights reserved.

Coherent laser vision system

International Nuclear Information System (INIS)

Sebastion, R.L.

1995-01-01

The Coherent Laser Vision System (CLVS) is being developed to provide precision real-time 3D world views to support site characterization and robotic operations and during facilities Decontamination and Decommissioning. Autonomous or semiautonomous robotic operations requires an accurate, up-to-date 3D world view. Existing technologies for real-time 3D imaging, such as AM laser radar, have limited accuracy at significant ranges and have variability in range estimates caused by lighting or surface shading. Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no-moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic to coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system

Coherent laser vision system

Energy Technology Data Exchange (ETDEWEB)

Sebastion, R.L. [Coleman Research Corp., Springfield, VA (United States)

1995-10-01

The Coherent Laser Vision System (CLVS) is being developed to provide precision real-time 3D world views to support site characterization and robotic operations and during facilities Decontamination and Decommissioning. Autonomous or semiautonomous robotic operations requires an accurate, up-to-date 3D world view. Existing technologies for real-time 3D imaging, such as AM laser radar, have limited accuracy at significant ranges and have variability in range estimates caused by lighting or surface shading. Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no-moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic to coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

Integral ceramic superstructure evaluation using time domain optical coherence tomography

Science.gov (United States)

Sinescu, Cosmin; Bradu, Adrian; Topala, Florin I.; Negrutiu, Meda Lavinia; Duma, Virgil-Florin; Podoleanu, Adrian G.

2014-02-01

Optical Coherence Tomography (OCT) is a non-invasive low coherence interferometry technique that includes several technologies (and the corresponding devices and components), such as illumination and detection, interferometry, scanning, adaptive optics, microscopy and endoscopy. From its large area of applications, we consider in this paper a critical aspect in dentistry - to be investigated with a Time Domain (TD) OCT system. The clinical situation of an edentulous mandible is considered; it can be solved by inserting 2 to 6 implants. On these implants a mesostructure will be manufactured and on it a superstructure is needed. This superstructure can be integral ceramic; in this case materials defects could be trapped inside the ceramic layers and those defects could lead to fractures of the entire superstructure. In this paper we demonstrate that a TD-OCT imaging system has the potential to properly evaluate the presence of the defects inside the ceramic layers and those defects can be fixed before inserting the prosthesis inside the oral cavity. Three integral ceramic superstructures were developed by using a CAD/CAM technology. After the milling, the ceramic layers were applied on the core. All the three samples were evaluated by a TD-OCT system working at 1300 nm. For two of the superstructures evaluated, no defects were found in the most stressed areas. The third superstructure presented four ceramic defects in the mentioned areas. Because of those defects the superstructure may fracture. The integral ceramic prosthesis was send back to the dental laboratory to fix the problems related to the material defects found. Thus, TD-OCT proved to be a valuable method for diagnosing the ceramic defects inside the integral ceramic superstructures in order to prevent fractures at this level.

Stimulated coherent transition radiation

International Nuclear Information System (INIS)

Hung-chi Lihn.

1996-03-01

Coherent radiation emitted from a relativistic electron bunch consists of wavelengths longer than or comparable to the bunch length. The intensity of this radiation out-numbers that of its incoherent counterpart, which extends to wavelengths shorter than the bunch length, by a factor equal to the number of electrons in the bunch. In typical accelerators, this factor is about 8 to 11 orders of magnitude. The spectrum of the coherent radiation is determined by the Fourier transform of the electron bunch distribution and, therefore, contains information of the bunch distribution. Coherent transition radiation emitted from subpicosecond electron bunches at the Stanford SUNSHINE facility is observed in the far-infrared regime through a room-temperature pyroelectric bolometer and characterized through the electron bunch-length study. To measure the bunch length, a new frequency-resolved subpicosecond bunch-length measuring system is developed. This system uses a far-infrared Michelson interferometer to measure the spectrum of coherent transition radiation through optical autocorrelation with resolution far better than existing time-resolved methods. Hence, the radiation spectrum and the bunch length are deduced from the autocorrelation measurement. To study the stimulation of coherent transition radiation, a special cavity named BRAICER is invented. Far-infrared light pulses of coherent transition radiation emitted from electron bunches are delayed and circulated in the cavity to coincide with subsequent incoming electron bunches. This coincidence of light pulses with electron bunches enables the light to do work on electrons, and thus stimulates more radiated energy. The possibilities of extending the bunch-length measuring system to measure the three-dimensional bunch distribution and making the BRAICER cavity a broadband, high-intensity, coherent, far-infrared light source are also discussed

Optical coherence tomography of the newborn airway.

Science.gov (United States)

Ridgway, James M; Su, Jianping; Wright, Ryan; Guo, Shuguang; Kim, David C; Barretto, Roberto; Ahuja, Gurpreet; Sepehr, Ali; Perez, Jorge; Sills, Jack H; Chen, Zhongping; Wong, Brian J F

2008-05-01

Acquired subglottic stenosis in a newborn is often associated with prolonged endotracheal intubation. This condition is generally diagnosed during operative endoscopy after airway injury has occurred. Unfortunately, endoscopy is unable to characterize the submucosal changes observed in such airway injuries. Other modalities, such as magnetic resonance imaging, computed tomography, and ultrasound, do not possess the necessary level of resolution to differentiate scar, neocartilage, and edema. Optical coherence tomography (OCT) is an imaging modality that produces high-resolution, cross-sectional images of living tissue (8 to 20 microm). We examined the ability of this noninvasive technique to characterize the newborn airway in a prospective clinical trial. Twelve newborn patients who required ventilatory support underwent OCT airway imaging. Comparative analysis of intubated and non-intubated states was performed. Imaging of the supraglottis, glottis, subglottis, and trachea was performed in 12 patients, revealing unique tissue characteristics as related to turbidity, signal backscattering, and architecture. Multiple structures were identified, including the vocal folds, cricoid cartilage, tracheal rings, ducts, glands, and vessels. Optical coherence tomography clearly identifies in vivo tissue layers and regional architecture while offering detailed information concerning tissue microstructures. The diagnostic potential of this technology makes OCT a promising modality in the study and surveillance of the neonatal airway.

Characteristics of scrub typhus, murine typhus, and Q fever among elderly patients: Prolonged prothrombin time as a predictor for severity.

Science.gov (United States)

Chang, Ko; Lee, Nan-Yao; Ko, Wen-Chien; Lin, Wei-Ru; Chen, Yen-Hsu; Tsai, Jih-Jin; Chen, Tun-Chieh; Lin, Chun-Yu; Chang, Ya-Ting; Lu, Po-Liang

2017-06-22

The clinical manifestations of scrub typhus, murine typhus and acute Q fever in the elderly are not clear. We conducted a retrospective study to identify the characteristics of the elderly aged ≥65 years with a comparison group aged 18-64 years among patients with scrub typhus, murine typhus, or acute Q fever who were serologically confirmed at three hospitals in Taiwan during 2002-2011. Among 441 cases, including 187 cases of scrub typhus, 166 acute Q fever, and 88 murine typhus, 68 (15.4%) cases were elderly patients. The elderly had a higher severe complication rate (10.3% vs. 3.5%, p = 0.022), but did not have a significantly higher mortality rate (1.47% vs. 0.54%, p = 0.396). Compared with those without severe complications, we found the elderly (p = 0.022), dyspnea (p = 0.006), less relative bradycardia (p = 0.004), less febrile illness (p = 0.004), prolonged prothrombin time (PT) (p = 0.002), higher levels of initial C-reactive protein (p = 0.039), blood leukocyte counts (p = 0.01), and lower platelet counts (p = 0.012) are significantly associated with severe complications. Only prolonged prothrombin time was associated with severe complications in multivariate analysis (p = 0.018, CI 95% 0.01-0.66). Among clinical symptoms and laboratory data, multivariate analysis revealed chills was less frequently occurred in the elderly (p = 0.012, 95% confidence interval [CI]: 1.33-9.99). The elderly cases with scrub typhus, murine typhus, or acute Q fever would be more likely to have severe complications, for which prothrombin time prolongation is an important predictor for severe complications. Copyright © 2017. Published by Elsevier B.V.

MO-F-CAMPUS-I-04: Characterization of Fan Beam Coded Aperture Coherent Scatter Spectral Imaging Methods for Differentiation of Normal and Neoplastic Breast Structures

Energy Technology Data Exchange (ETDEWEB)

Morris, R; Albanese, K; Lakshmanan, M; Greenberg, J; Kapadia, A [Duke University Medical Center, Durham, NC, Carl E Ravin Advanced Imaging Laboratories, Durham, NC (United States)

2015-06-15

Purpose: This study intends to characterize the spectral and spatial resolution limits of various fan beam geometries for differentiation of normal and neoplastic breast structures via coded aperture coherent scatter spectral imaging techniques. In previous studies, pencil beam raster scanning methods using coherent scatter computed tomography and selected volume tomography have yielded excellent results for tumor discrimination. However, these methods don’t readily conform to clinical constraints; primarily prolonged scan times and excessive dose to the patient. Here, we refine a fan beam coded aperture coherent scatter imaging system to characterize the tradeoffs between dose, scan time and image quality for breast tumor discrimination. Methods: An X-ray tube (125kVp, 400mAs) illuminated the sample with collimated fan beams of varying widths (3mm to 25mm). Scatter data was collected via two linear-array energy-sensitive detectors oriented parallel and perpendicular to the beam plane. An iterative reconstruction algorithm yields images of the sample’s spatial distribution and respective spectral data for each location. To model in-vivo tumor analysis, surgically resected breast tumor samples were used in conjunction with lard, which has a form factor comparable to adipose (fat). Results: Quantitative analysis with current setup geometry indicated optimal performance for beams up to 10mm wide, with wider beams producing poorer spatial resolution. Scan time for a fixed volume was reduced by a factor of 6 when scanned with a 10mm fan beam compared to a 1.5mm pencil beam. Conclusion: The study demonstrates the utility of fan beam coherent scatter spectral imaging for differentiation of normal and neoplastic breast tissues has successfully reduced dose and scan times whilst sufficiently preserving spectral and spatial resolution. Future work to alter the coded aperture and detector geometries could potentially allow the use of even wider fans, thereby making coded

Partially coherent imaging and spatial coherence wavelets

International Nuclear Information System (INIS)

Castaneda, Roman

2003-03-01

A description of spatially partially coherent imaging based on the propagation of second order spatial coherence wavelets and marginal power spectra (Wigner distribution functions) is presented. In this dynamics, the spatial coherence wavelets will be affected by the system through its elementary transfer function. The consistency of the model with the both extreme cases of full coherent and incoherent imaging was proved. In the last case we obtained the classical concept of optical transfer function as a simple integral of the elementary transfer function. Furthermore, the elementary incoherent response function was introduced as the Fourier transform of the elementary transfer function. It describes the propagation of spatial coherence wavelets form each object point to each image point through a specific point on the pupil planes. The point spread function of the system was obtained by a simple integral of the elementary incoherent response function. (author)

Quantum coherence in the reflection of above barrier wavepackets

Science.gov (United States)

Petersen, Jakob; Pollak, Eli

2018-02-01

The quantum phenomenon of above barrier reflection is investigated from a time-dependent perspective using Gaussian wavepackets. The transition path time distribution, which in principle is experimentally measurable, is used to study the mean flight times ⟨t⟩R and ⟨t⟩T associated with the reflection and the transmission over the barrier paying special attention to their dependence on the width of the barrier. Both flight times, and their difference Δt, exhibit two distinct regimes depending on the ratio of the spatial width of the incident wavepacket and the length of the barrier. When the ratio is larger than unity, the reflection and transmission dynamics are coherent and dominated by the resonances above the barrier. The flight times ⟨t⟩R/T and the flight time difference Δt oscillate as a function of the barrier width (almost in phase with the transmission probability). These oscillations reflect a momentum filtering effect related to the coherent superposition of the reflected and transmitted waves. For a ratio less than unity, the barrier reflection and transmission dynamics are incoherent and the oscillations are absent. The barrier width which separates the coherent and incoherent regimes is identified analytically. The oscillatory structure of the time difference Δt as a function of the barrier width in the coherent regime is absent when considered in terms of the Wigner phase time delays for reflection and transmission. We conclude that the Wigner phase time does not correctly describe the temporal properties of above barrier reflection. We also find that the structure of the reflected and transmitted wavepackets depends on the coherence of the process. In the coherent regime, the wavepackets can have an overlapping peak structure, but the peaks are not fully resolved. In the incoherent regime, the wavepackets split in time into distinct separated Gaussian like waves, each one reflecting the number of times the wavepacket crosses the barrier

Exergy of partially coherent thermal radiation

International Nuclear Information System (INIS)

Wijewardane, S.; Goswami, Yogi

2012-01-01

Exergy of electromagnetic radiation has been studied by a number of researchers for well over four decades in order to estimate the maximum conversion efficiencies of thermal radiation. As these researchers primarily dealt with solar and blackbody radiation, which have a low degree of coherence, they did not consider the partial coherence properties of thermal radiation. With the recent development of surface structures, which can emit radiation with high degree of coherence, the importance of considering the partial coherent properties in exergy calculation has become a necessity as the coherence properties directly influence the entropy of the wave field. Here in this paper we derive an expression for the exergy of quasi-monochromatic radiation using statistical thermodynamics and show that it is identical with the expressions derived using classical thermodynamics. We also present a method to calculate the entropy, thereby the exergy of partially coherent radiation using statistical thermodynamics and a method called matrix treatment of wave field. -- Highlights: ► Considered partial coherence of radiation for the first time to calculate exergy. ► The importance of this method is emphasized with energy conversion examples. ► Derived an expression for the exergy of radiation using statistical thermodynamics. ► Adopted a method to calculate intensity of statistically independent principle wave.

Analysis of NPP pipes and equipment damage in life time prolongation

International Nuclear Information System (INIS)

Tkachev, V.V.; Zheltukhin, K.K.

2008-01-01

Paper describes a procedure to calculate the probability of pipes and equipment failure taking account of both the service records of the structures under various conditions and their aging. The parameters characterizing applied loads, failures, as well as metal strength, mechanical and thermal properties serve as the arbitrary values used in the described procedure. Paper presents an example of the probability calculation of failure of the RBMK emergency feed pump recirculation pipes when their service life is prolonged [ru

Quantum Coherent Dynamics Enhanced by Synchronization with Nonequilibrium Environments

Science.gov (United States)

Ishikawa, Akira; Okada, Ryo; Uchiyama, Kazuharu; Hori, Hirokazu; Kobayashi, Kiyoshi

2018-05-01

We report the discovery of the anomalous enhancement of quantum coherent dynamics (CD) due to a non-Markovian mechanism originating from not thermal-equilibrium phonon baths but nonequilibrium coherent phonons. CD is an elementary process for quantum phenomena in nanosystems, such as excitation transfer (ET) in semiconductor nanostructures and light-harvesting systems. CD occurs in homogeneous nanosystems because system inhomogeneity typically destroys coherence. In real systems, however, nanosystems behave as open systems surrounded by environments such as phonon systems. Typically, CD in inhomogeneous nanosystems is enhanced by the absorption and emission of thermal-equilibrium phonons, and the enhancement is described by the conventional master equation. On the other hand, CD is also enhanced by synchronization between population dynamics in nanosystems and coherent phonons; namely, coherent phonons, which are self-consistently induced by phase matching with Rabi oscillation, are fed back to enhance CD. This anomalous enhancement of CD essentially originates from the nonequilibrium and dynamical non-Markovian nature of coherent phonon environments, and the enhancement is firstly predicted by applying time-dependent projection operators to nonequilibrium and dynamical environments. Moreover, CD is discussed by considering ET from a donor to an acceptor. It is found that the enhancement of ET by synchronization with coherent phonons depends on the competition between the output time from a system to an acceptor and the formation time of coherent phonons. These findings in this study will stimulate the design and manipulation of CD via structured environments from the viewpoint of application to nano-photoelectronic devices.

Vision and Vestibular System Dysfunction Predicts Prolonged Concussion Recovery in Children.

Science.gov (United States)

Master, Christina L; Master, Stephen R; Wiebe, Douglas J; Storey, Eileen P; Lockyer, Julia E; Podolak, Olivia E; Grady, Matthew F

2018-03-01

Up to one-third of children with concussion have prolonged symptoms lasting beyond 4 weeks. Vision and vestibular dysfunction is common after concussion. It is unknown whether such dysfunction predicts prolonged recovery. We sought to determine which vision or vestibular problems predict prolonged recovery in children. A retrospective cohort of pediatric patients with concussion. A subspecialty pediatric concussion program. Four hundred thirty-two patient records were abstracted. Presence of vision or vestibular dysfunction upon presentation to the subspecialty concussion program. The main outcome of interest was time to clinical recovery, defined by discharge from clinical follow-up, including resolution of acute symptoms, resumption of normal physical and cognitive activity, and normalization of physical examination findings to functional levels. Study subjects were 5 to 18 years (median = 14). A total of 378 of 432 subjects (88%) presented with vision or vestibular problems. A history of motion sickness was associated with vestibular dysfunction. Younger age, public insurance, and presence of headache were associated with later presentation for subspecialty concussion care. Vision and vestibular problems were associated within distinct clusters. Provocable symptoms with vestibulo-ocular reflex (VOR) and smooth pursuits and abnormal balance and accommodative amplitude (AA) predicted prolonged recovery time. Vision and vestibular problems predict prolonged concussion recovery in children. A history of motion sickness may be an important premorbid factor. Public insurance status may represent problems with disparities in access to concussion care. Vision assessments in concussion must include smooth pursuits, saccades, near point of convergence (NPC), and accommodative amplitude (AA). A comprehensive, multidomain assessment is essential to predict prolonged recovery time and enable active intervention with specific school accommodations and targeted rehabilitation.

The global coherence initiative: creating a coherent planetary standing wave.

Science.gov (United States)

McCraty, Rollin; Deyhle, Annette; Childre, Doc

2012-03-01

The much anticipated year of 2012 is now here. Amidst the predictions and cosmic alignments that many are aware of, one thing is for sure: it will be an interesting and exciting year as the speed of change continues to increase, bringing both chaos and great opportunity. One benchmark of these times is a shift in many people from a paradigm of competition to one of greater cooperation. All across the planet, increasing numbers of people are practicing heart-based living, and more groups are forming activities that support positive change and creative solutions for manifesting a better world. The Global Coherence Initiative (GCI) is a science-based, co-creative project to unite people in heart-focused care and intention. GCI is working in concert with other initiatives to realize the increased power of collective intention and consciousness. The convergence of several independent lines of evidence provides strong support for the existence of a global information field that connects all living systems and consciousness. Every cell in our bodies is bathed in an external and internal environment of fluctuating invisible magnetic forces that can affect virtually every cell and circuit in biological systems. Therefore, it should not be surprising that numerous physiological rhythms in humans and global collective behaviors are not only synchronized with solar and geomagnetic activity, but disruptions in these fields can create adverse effects on human health and behavior. The most likely mechanism for explaining how solar and geomagnetic influences affect human health and behavior are a coupling between the human nervous system and resonating geomagnetic frequencies, called Schumann resonances, which occur in the earth-ionosphere resonant cavity and Alfvén waves. It is well established that these resonant frequencies directly overlap with those of the human brain and cardiovascular system. If all living systems are indeed interconnected and communicate with each other

The Significance of Prolonged and Saddleback Fever in Hospitalised Adult Dengue.

Directory of Open Access Journals (Sweden)

Deborah Hl Ng

Full Text Available Dengue fever is gaining importance in Singapore with an increase in the number of cases and mortality in recent years. Although prolonged and saddleback fever have been reported in dengue fever, there are no specific studies on their significance in dengue. This study aims to examine the prevalence of prolonged and saddleback fever in dengue as well as their associations with dengue severity. A total of 2843 polymerase-chain reaction (PCR confirmed dengue patients admitted to Tan Tock Seng Hospital from 2004 to 2008 were included in the study. Sixty-nine percent of them were male with a median age of 34 years. Prolonged fever (fever > 7 days duration was present in 572 (20.1% of patients. Dengue hemorrhagic fever (DHF, dengue shock syndrome (DSS and severe dengue (SD were significantly more likely to occur in patients with prolonged fever. Mucosal bleeding, anorexia, diarrhea, abdominal pain, nausea or vomiting, lethargy, rash, clinical fluid accumulation, hepatomegaly, nosocomial infection, leukopenia, higher neutrophil count, higher hematocrit, higher alanine transaminase (ALT and aspartate transaminase (AST, higher creatinine, lower protein and prolonged activated partial thromboplastin time (APTT were significantly associated with prolonged fever but not platelet count or prothrombin time (PT. Saddleback fever was present in 165 (5.8%. Although DHF and SD were more likely to occur in patients in those with saddleback fever, DSS was not. Compared with prolonged fever, saddleback fever did not show many significant associations except for diarrhea, abdominal pain, clinical fluid accumulation, hematocrit and platelet change, and lower systolic blood pressure. This study demonstrates that prolonged fever may be associated with various warning signs and more severe forms of dengue (SD, DSS, DHF, while saddleback fever showed associations with DHF and SD but not DSS. The presence of prolonged or saddleback fever in dengue patients should therefore

Coherence properties and quantum state transportation in an optical conveyor belt.

Science.gov (United States)

Kuhr, S; Alt, W; Schrader, D; Dotsenko, I; Miroshnychenko, Y; Rosenfeld, W; Khudaverdyan, M; Gomer, V; Rauschenbeutel, A; Meschede, D

2003-11-21

We have prepared and detected quantum coherences of trapped cesium atoms with long dephasing times. Controlled transport by an "optical conveyor belt" over macroscopic distances preserves the atomic coherence with slight reduction of coherence time. The limiting dephasing effects are experimentally identified, and we present an analytical model of the reversible and irreversible dephasing mechanisms. Our experimental methods are applicable at the single-atom level. Coherent quantum bit operations along with quantum state transport open the route towards a "quantum shift register" of individual neutral atoms.

Design of FBG En/decoders in Coherent 2-D Time-polarization OCDMA Systems

Science.gov (United States)

Hou, Fen-fei; Yang, Ming

2012-12-01

A novel fiber Bragg grating (FBG)-based en/decoder for the two-dimensional (2-D) time-spreading and polarization multiplexer optical coding is proposed. Compared with other 2-D en/decoders, the proposed en/decoding for an optical code-division multiple-access (OCDMA) system uses a single phase-encoded FBG and coherent en/decoding. Furthermore, combined with reconstruction-equivalent-chirp technology, such en/decoders can be realized with a conventional simple fabrication setup. Experimental results of such en/decoders and the corresponding system test at a data rate of 5 Gbit/s demonstrate that this kind of 2-D FBG-based en/decoders could improve the performances of OCDMA systems.

Analytic coherent states for generalized potentials

International Nuclear Information System (INIS)

Nieto, M.M.; Simmons, L.M. Jr.

1978-01-01

A prescription is given for finding coherent states in generalized potentials. By coherent states is meant states which in time follow the motion that a classical particle would. This prescription is based upon finding those natural classical variables which vary as the sine and the cosine of the classical ω/sub c/t. As an example, the symmetric Rosen--Morse potential is discussed in detail

Role of initial coherence on entanglement dynamics of two qubit X states

Science.gov (United States)

V, Namitha C.; Satyanarayana, S. V. M.

2018-02-01

Bipartite entanglement is a necessary resource in most processes in quantum information science. Decoherence resulting from the interaction of the bipartite system with environment not only degrades the entanglement, but can result in abrupt disentanglement, known as entanglement sudden death (ESD). In some cases, a subsequent revival of entanglement is also possible. ESD is an undesirable feature for the state to be used as a resource in applications. In order to delay or avoid ESD, it is necessary to understand its origin. In this work we investigate the role of initial coherence on entanglement dynamics of a spatially separated two qubit system in a common vacuum reservoir with dipolar interaction. We construct two classes of X states, namely, states with one photon coherence (X 1) and states with two photon coherence (X 2). Considering them as initial states, we study entanglement dynamics under Markov approximation. We find for states in X 1, ESD time, revival time and time over which the state remains disentangled increase with increase in coherence. On the other hand for states in X 2, with increase in coherence ESD time increases, revival time remains same and time of disentanglement decreases. Thus, states with two photon coherence are better resources for applications since their entanglement is robust against decoherence compared to states with one photon coherence.

Developing community based rehabilitation for cancer survivors: organizing for coordination and coherence in practice

Science.gov (United States)

2013-01-01

Background Increasing incidences of cancer combined with prolonged survival have raised the need for developing community based rehabilitation. The objectives of the analysis were to describe and interpret the key issues related to coordination and coherence of community-based cancer rehabilitation in Denmark and to provide insights relevant for other contexts. Methods Twenty-seven rehabilitation managers across 15 municipalities in Denmark comprised the sample. The study was designed with a combination of data collection methods including questionnaires, individual interviews, and focus groups. A Grounded Theory approach was used to analyze the data. Results A lack of shared cultures among health care providers and systems of delivery was a primary barrier to collaboration which was essential for establishing coordination of care. Formal multidisciplinary steering committees, team-based organization, and informal relationships were fundamental for developing coordination and coherence. Conclusions Coordination and coherence in community-based rehabilitation relies on increased collaboration, which may best be optimized by use of shared frameworks within and across systems. Results highlight the challenges faced in practical implementation of community rehabilitation and point to possible strategies for its enhancement. PMID:24004881

Prolonged warm ischemia time is associated with graft failure and mortality after kidney transplantation.

Science.gov (United States)

Tennankore, Karthik K; Kim, S Joseph; Alwayn, Ian P J; Kiberd, Bryce A

2016-03-01

Warm ischemia time is a potentially modifiable insult to transplanted kidneys, but little is known about its effect on long-term outcomes. Here we conducted a study of United States kidney transplant recipients (years 2000-2013) to determine the association between warm ischemia time (the time from organ removal from cold storage to reperfusion with warm blood) and death/graft failure. Times under 10 minutes were potentially attributed to coding error. Therefore, the 10-to-under-20-minute interval was chosen as the reference group. The primary outcome was mortality and graft failure (return to chronic dialysis or preemptive retransplantation) adjusted for recipient, donor, immunologic, and surgical factors. The study included 131,677 patients with 35,901 events. Relative to the reference patients, times of 10 to under 20, 20 to under 30, 30 to under 40, 40 to under 50, 50 to under 60, and 60 and more minutes were associated with hazard ratios of 1.07 (95% confidence interval, 0.99-1.15), 1.13 (1.06-1.22), 1.17 (1.09-1.26), 1.20 (1.12-1.30), and 1.23 (1.15-1.33) for the composite event, respectively. Association between prolonged warm ischemia time and death/graft failure persisted after stratification by donor type (living vs. deceased donor) and delayed graft function status. Thus, warm ischemia time is associated with adverse long-term patient and graft survival after kidney transplantation. Identifying strategies to reduce warm ischemia time is an important consideration for future study. Copyright © 2015 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Polarization Sensitive Coherent Raman Measurements of DCVJ

Science.gov (United States)

Anderson, Josiah; Cooper, Nathan; Lawhead, Carlos; Shiver, Tegan; Ujj, Laszlo

2014-03-01

Coherent Raman spectroscopy which recently developed into coherent Raman microscopy has been used to produce label free imaging of thin layers of material and find the spatial distributions of certain chemicals within samples, e.g. cancer cells.(1) Not all aspects of coherent scattering have been used for imaging. Among those for example are special polarization sensitive measurements. Therefore we have investigated the properties of polarization sensitive CARS spectra of a highly fluorescent molecule, DCVJ.(2) Spectra has been recorded by using parallel polarized and perpendicular polarized excitations. A special polarization arrangement was developed to suppress the non-resonant background scattering from the sample. These results can be used to improve the imaging properties of a coherent Raman microscope in the future. This is the first time coherent Raman polarization sensitive measurements have been used to characterize the vibrational modes of DCVJ. 1: K. I. Gutkowski, et al., ``Fluorescence of dicyanovinyl julolidine in a room temperature ionic liquid '' Chemical Physics Letters 426 (2006) 329 - 333 2: Fouad El-Diasty, ``Coherent anti-Stokes Raman scattering: Spectroscopy and microscopy'' Vibrational Spectroscopy 55 (2011) 1-37

arXiv Quantum coherence of cosmological perturbations

CERN Document Server

Giovannini, Massimo

2017-10-26

In this paper, the degrees of quantum coherence of cosmological perturbations of different spins are computed in the large-scale limit and compared with the standard results holding for a single mode of the electromagnetic field in an optical cavity. The degree of second-order coherence of curvature inhomogeneities (and, more generally, of the scalar modes of the geometry) reproduces faithfully the optical limit. For the vector and tensor fluctuations, the numerical values of the normalized degrees of second-order coherence in the zero time-delay limit are always larger than unity (which is the Poisson benchmark value) but differ from the corresponding expressions obtainable in the framework of the single-mode approximation. General lessons are drawn on the quantum coherence of large-scale cosmological fluctuations.

Time-dependent Wigner distribution function employed in coherent Schroedinger cat states: |Ψ(t))=N-1/2(|α)+eiφ|-α))

International Nuclear Information System (INIS)

Choi, Jeong Ryeol; Yeon, Kyu Hwang

2008-01-01

The Wigner distribution function for the time-dependent quadratic Hamiltonian system in the coherent Schroedinger cat state is investigated. The type of state we consider is a superposition of two coherent states, which are by an angle of π out of phase with each other. The exact Wigner distribution function of the system is evaluated under a particular choice of phase, δ c,q . Our development is employed for two special cases, namely, the Caldirola-Kanai oscillator and the frequency stable damped harmonic oscillator. On the basis of the diverse values of the Wigner distribution function that were plotted, we analyze the nonclassical behavior of the systems.

Geometric phases for nonlinear coherent and squeezed states

International Nuclear Information System (INIS)

Yang Dabao; Chen Ying; Chen Jingling; Zhang Fulin

2011-01-01

The geometric phases for standard coherent states which are widely used in quantum optics have attracted considerable attention. Nevertheless, few physicists consider the counterparts of nonlinear coherent states, which are useful in the description of the motion of a trapped ion. In this paper, the non-unitary and non-cyclic geometric phases for two nonlinear coherent and one squeezed states are formulated, respectively. Moreover, some of their common properties are discussed, such as gauge invariance, non-locality and nonlinear effects. The nonlinear functions have dramatic impacts on the evolution of the corresponding geometric phases. They speed the evolution up or down. So this property may have an application in controlling or measuring geometric phase. For the squeezed case, when the squeezed parameter r → ∞, the limiting value of the geometric phase is also determined by a nonlinear function at a given time and angular velocity. In addition, the geometric phases for standard coherent and squeezed states are obtained under a particular condition. When the time evolution undergoes a period, their corresponding cyclic geometric phases are achieved as well. And the distinction between the geometric phases of the two coherent states may be regarded as a geometric criterion.

Coherence characteristics of random lasing in a dye doped hybrid powder

Energy Technology Data Exchange (ETDEWEB)

García-Revilla, S. [Departamento de Física Aplicada I, Escuela Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alda. Urquijo s/n, 48013, Bilbao (Spain); Material Physics Center CSIC-UPV/EHU and Donostia International Physics Center, 20018, San Sebastián (Spain); Fernández, J., E-mail: wupferoj@bi.ehu.es [Departamento de Física Aplicada I, Escuela Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alda. Urquijo s/n, 48013, Bilbao (Spain); Material Physics Center CSIC-UPV/EHU and Donostia International Physics Center, 20018, San Sebastián (Spain); Barredo-Zuriarrain, M. [Departamento de Física Aplicada I, Escuela Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alda. Urquijo s/n, 48013, Bilbao (Spain); Pecoraro, E. [Instituto de Telecomunicações, University of Aveiro, 3810-193, Aveiro (Portugal); Institute of Chemisty, São Paulo State University–UNESP, 14800-900, Araraquara (Brazil); Arriandiaga, M.A. [Departamento de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apartado 644, Bilbao (Spain); Iparraguirre, I.; Azkargorta, J. [Departamento de Física Aplicada I, Escuela Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alda. Urquijo s/n, 48013, Bilbao (Spain); and others

2016-01-15

The photon statistics of the random laser emission of a Rhodamine B doped di-ureasil hybrid powder is investigated to evaluate its degree of coherence above threshold. Although the random laser emission is a weighted average of spatially uncorrelated radiation emitted at different positions in the sample, a spatial coherence control was achieved due to an improved detection configuration based on spatial filtering. By using this experimental approach, which also allows for fine mode discrimination and time-resolved analysis of uncoupled modes from mode competition, an area not larger than the expected coherence size of the random laser is probed. Once the spectral and temporal behavior of non-overlapping modes is characterized, an assessment of the photon-number probability distribution and the resulting second-order correlation coefficient as a function of time delay and wavelength was performed. The outcome of our single photon counting measurements revealed a high degree of temporal coherence at the time of maximum pump intensity and at wavelengths around the Rhodamine B gain maximum. - Highlights: • The photon statistics of a diffusive random laser is explored. • The laser sample is a RhB doped di-ureasil hybrid powder. • The detection configuration allows for mode discrimination and time-resolved analysis. • The time and wavelength variation of the temporal coherence is examined. • A high degree of temporal coherence is found.

Cohering power of quantum operations

Energy Technology Data Exchange (ETDEWEB)

Bu, Kaifeng, E-mail: bkf@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China); Kumar, Asutosh, E-mail: asukumar@hri.res.in [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Zhang, Lin, E-mail: linyz@zju.edu.cn [Institute of Mathematics, Hangzhou Dianzi University, Hangzhou 310018 (China); Wu, Junde, E-mail: wjd@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China)

2017-05-18

Highlights: • Quantum coherence. • Cohering power: production of quantum coherence by quantum operations. • Study of cohering power and generalized cohering power, and their comparison for differentmeasures of quantum coherence. • Operational interpretation of cohering power. • Bound on cohering power of a generic quantum operation. - Abstract: Quantum coherence and entanglement, which play a crucial role in quantum information processing tasks, are usually fragile under decoherence. Therefore, the production of quantum coherence by quantum operations is important to preserve quantum correlations including entanglement. In this paper, we study cohering power–the ability of quantum operations to produce coherence. First, we provide an operational interpretation of cohering power. Then, we decompose a generic quantum operation into three basic operations, namely, unitary, appending and dismissal operations, and show that the cohering power of any quantum operation is upper bounded by the corresponding unitary operation. Furthermore, we compare cohering power and generalized cohering power of quantum operations for different measures of coherence.

Coherent electron cooling

Energy Technology Data Exchange (ETDEWEB)

Litvinenko,V.

2009-05-04

Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

Coherent betatron instability in the Tevatron

International Nuclear Information System (INIS)

Bogacz, S.A.; Harrison, M.; Ng, K.Y.

1988-01-01

The coherent betatron instability was first observed during the recent 1987-88 Tevatron fixed target run. In this operating mode 1000 consecutive bunches are loaded into the machine at 150 GeV with a bunch spacing of 18.8 /times/ 10 -9 sec (53 MHz). The normalized transverse emittance is typically 15 π /times/ 10 -6 m rad in each plane with a longitudinal emittance of about 1.5 eV-sec. The beam is accelerated to 800 GeV in 13 sec. and then it is resonantly extracted during a 23 sec flat top. As the run progressed the bunch intensities were increased until at about 1.4 /times/ 10 10 ppb (protons per bunch) we experienced the onset of a coherent horizontal oscillation taking place in the later stages of the acceleration cycle (>600 GeV). This rapidly developing coherent instability results in a significant emittance growth, which limits machine performance and in a catastrophic scenario it even prevents extraction of the beam. In this paper we will present a simple analytic description of the observed instability. We will show that a combination of a resistive wall coupled bunch effect and a single bunch slow head-tail instability is consistent with the above observations. Finally, a systematic numerical analysis of our model (growth-time vs chromaticity plots) points to the existence of the ≥1 slow head-tail modes as a plausible mechanism for the observed coherent instability. This last claim, as mentioned before, does not have conclusive experimental evidence, although it is based on a very good agreement between the measured values of the instability growth-time and the ones calculated on the basis of our model. 4 refs., 3 figs

Prolongation of bleeding time and inhibition of platelet aggregation by low-dose acetylsalicylic acid in patients with cerebrovascular disease

DEFF Research Database (Denmark)

Boysen, G; Boss, A H; Ødum, Niels

1984-01-01

the bleeding time averaged 11.2 minutes in contrast to 7.0 minutes in the placebo group, p less than 0.001. This study confirms our previous findings of platelet inhibition by low-dose acetylsalicylic acid in patients with cerebrovascular disease. The prolongation of the bleeding time demonstrates that we......Platelet aggregation and bleeding time was measured in 43 cerebrovascular patients participating in a controlled double-blind study of low-dose acetylsalicylic acid. In 19 patients with satisfactory inhibition of the platelet aggregation obtained by 50 to 70 mg acetylsalicylic acid per day...... are dealing not merely with an in vitro phenomenon but with a significant in vivo effect. The study provides the rationale for clinical evaluations of low-dose acetylsalicylic acid in stroke prophylaxis....

Nuclear spin cooling by electric dipole spin resonance and coherent population trapping

Science.gov (United States)

Li, Ai-Xian; Duan, Su-Qing; Zhang, Wei

2017-09-01

Nuclear spin fluctuation suppression is a key issue in preserving electron coherence for quantum information/computation. We propose an efficient way of nuclear spin cooling in semiconductor quantum dots (QDs) by the coherent population trapping (CPT) and the electric dipole spin resonance (EDSR) induced by optical fields and ac electric fields. The EDSR can enhance the spin flip-flop rate and may bring out bistability under certain conditions. By tuning the optical fields, we can avoid the EDSR induced bistability and obtain highly polarized nuclear spin state, which results in long electron coherence time. With the help of CPT and EDSR, an enhancement of 1500 times of the electron coherence time can been obtained after a 500 ns preparation time.

Spin Coherence in Semiconductor Nanostructures

National Research Council Canada - National Science Library

Flatte, Michael E

2006-01-01

... dots, tuning of spin coherence times for electron spin, tuning of dipolar magnetic fields for nuclear spin, spontaneous spin polarization generation and new designs for spin-based teleportation and spin transistors...

Hippocampal Abnormalities after Prolonged Febrile Convulsions

Directory of Open Access Journals (Sweden)

J Gordon Millichap

2003-11-01

Full Text Available Hippocampal volume and T2 relaxation times were determined in an MRI study of 14 children with prolonged febrile convulsions (PFC who were investigated, 1 within 5 days of a PFC, and 2 at follow-up 4-8 months after the acute study, at the Institute of Child Health, University College, and Great Ormond Street Hospital, London, UK.

Spectral coherent combination of ultrashort pulses

International Nuclear Information System (INIS)

Ursescu, D.; Banici, R.; Ionel, L.; Rusen, L.; Sandel, S.; Blanaru, C.

2010-01-01

Complete text of publication follows. The coherent beam combination was chosen in several laser systems, including ELI, as a solution to increase the final attainable intensity. However, the coherent beam combination it is also a difficult technique while it has to combine coherently in space and in time several beams amplified in different laser chains. That means in particular that the beams should be in phase in every point of the amplified beam so the spatial beam profiling techniques have to be mastered with high accuracy for all the combined beams. Here it is proposed an alternative coherent beam combination than the use of identical ultrashort pulses. The idea is to spectrally combine laser pulses with complementary spectra. Collinear and non-collinear approaches have been modelled. Ongoing experimental development, including the demonstration of the rephasing for two spectrally complementary ultrashort pulses will be presented. Acknowledgements. The research leading to these results has received funding from the EC's Seventh Framework Programme (LASERLAB-EUROPE, grant agreement no. 228334).

Cold atoms near superconductors: atomic spin coherence beyond the Johnson noise limit

International Nuclear Information System (INIS)

Kasch, B; Hattermann, H; Cano, D; Judd, T E; Zimmermann, C; Kleiner, R; Koelle, D; Fortagh, J; Scheel, S

2010-01-01

We report on the measurement of atomic spin coherence near the surface of a superconducting niobium wire. As compared to normal conducting metal surfaces, the atomic spin coherence is maintained for time periods beyond the Johnson noise limit. The result provides experimental evidence that magnetic near-field noise near the superconductor is strongly suppressed. Such long atomic spin coherence times near superconductors open the way towards the development of coherently coupled cold atom/solid state hybrid quantum systems with potential applications in quantum information processing and precision force sensing.

SALIVARY ANTIMICROBIAL PROTEIN RESPONSE TO PROLONGED RUNNING

Directory of Open Access Journals (Sweden)

Suzanne Schneider

2013-01-01

Full Text Available Prolonged exercise may compromise immunity through a reduction of salivary antimicrobial proteins (AMPs. Salivary IgA (IgA has been extensively studied, but little is known about the effect of acute, prolonged exercise on AMPs including lysozyme (Lys and lactoferrin (Lac. Objective: To determine the effect of a 50-km trail race on salivary cortisol (Cort, IgA, Lys, and Lac. Methods: 14 subjects: (6 females, 8 males completed a 50km ultramarathon. Saliva was collected pre, immediately after (post and 1.5 hrs post race ( 1.5. Results: Lac concentration was higher at 1.5 hrs post race compared to post exercise (p0.05. IgA concentration, secretion rate, and IgA/Osm were lower 1.5 hrs post compared to pre race (p<0.05. Cort concentration was higher at post compared to 1.5 (p<0.05, but was unaltered from pre race levels. Subjects finished in 7.81 ± 1.2 hrs. Saliva flow rate did not differ between time points. Saliva Osm increased at post (p<0.05 compared to pre race. Conclusions: The intensity could have been too low to alter Lys and Lac secretion rates and thus, may not be as sensitive as IgA to changes in response to prolonged running. Results expand our understanding of the mucosal immune system and may have implications for predicting illness after prolonged running.

Spatial variability of excess mortality during prolonged dust events in a high-density city: a time-stratified spatial regression approach.

Science.gov (United States)

Wong, Man Sing; Ho, Hung Chak; Yang, Lin; Shi, Wenzhong; Yang, Jinxin; Chan, Ta-Chien

2017-07-24

Dust events have long been recognized to be associated with a higher mortality risk. However, no study has investigated how prolonged dust events affect the spatial variability of mortality across districts in a downwind city. In this study, we applied a spatial regression approach to estimate the district-level mortality during two extreme dust events in Hong Kong. We compared spatial and non-spatial models to evaluate the ability of each regression to estimate mortality. We also compared prolonged dust events with non-dust events to determine the influences of community factors on mortality across the city. The density of a built environment (estimated by the sky view factor) had positive association with excess mortality in each district, while socioeconomic deprivation contributed by lower income and lower education induced higher mortality impact in each territory planning unit during a prolonged dust event. Based on the model comparison, spatial error modelling with the 1st order of queen contiguity consistently outperformed other models. The high-risk areas with higher increase in mortality were located in an urban high-density environment with higher socioeconomic deprivation. Our model design shows the ability to predict spatial variability of mortality risk during an extreme weather event that is not able to be estimated based on traditional time-series analysis or ecological studies. Our spatial protocol can be used for public health surveillance, sustainable planning and disaster preparation when relevant data are available.

Smoking prolongs the infectivity of patients with tuberculosis.

LENUS (Irish Health Repository)

Siddiqui, U A

2010-10-01

We sought to establish if smokers on anti-tuberculosis treatment are more likely to have a prolonged period of infectivity, compared to non-smoking tuberculosis patients, in a low tuberculosis prevalence country. We conducted a cross-sectional, retrospective study in Ireland that recruited 53 microbiologically confirmed cases of pulmonary tuberculosis (PTB). The age-sex adjusted odds ratios (AOR) suggest that the infectivity status of PTB on treatment was four times more likely to be prolonged beyond 6-8 weeks, if the cases had a smoking history (AOR: 4.42; 95% CI: 1.23; 15.9). Smoking was associated with delayed sputum smear conversion in PTB patients on treatment.

Coherent Dynamics of a Hybrid Quantum Spin-Mechanical Oscillator System

Science.gov (United States)

Lee, Kenneth William, III

A fully functional quantum computer must contain at least two important components: a quantum memory for storing and manipulating quantum information and a quantum data bus to securely transfer information between quantum memories. Typically, a quantum memory is composed of a matter system, such as an atom or an electron spin, due to their prolonged quantum coherence. Alternatively, a quantum data bus is typically composed of some propagating degree of freedom, such as a photon, which can retain quantum information over long distances. Therefore, a quantum computer will likely be a hybrid quantum device, consisting of two or more disparate quantum systems. However, there must be a reliable and controllable quantum interface between the memory and bus in order to faithfully interconvert quantum information. The current engineering challenge for quantum computers is scaling the device to large numbers of controllable quantum systems, which will ultimately depend on the choice of the quantum elements and interfaces utilized in the device. In this thesis, we present and characterize a hybrid quantum device comprised of single nitrogen-vacancy (NV) centers embedded in a high quality factor diamond mechanical oscillator. The electron spin of the NV center is a leading candidate for the realization of a quantum memory due to its exceptional quantum coherence times. On the other hand, mechanical oscillators are highly sensitive to a wide variety of external forces, and have the potential to serve as a long-range quantum bus between quantum systems of disparate energy scales. These two elements are interfaced through crystal strain generated by vibrations of the mechanical oscillator. Importantly, a strain interface allows for a scalable architecture, and furthermore, opens the door to integration into a larger quantum network through coupling to an optical interface. There are a few important engineering challenges associated with this device. First, there have been no

COMPARISON OF SOLAR SURFACE FLOWS INFERRED FROM TIME-DISTANCE HELIOSEISMOLOGY AND COHERENT STRUCTURE TRACKING USING HMI/SDO OBSERVATIONS

International Nuclear Information System (INIS)

Švanda, Michal; Roudier, Thierry; Rieutord, Michel; Burston, Raymond; Gizon, Laurent

2013-01-01

We compare measurements of horizontal flows on the surface of the Sun using helioseismic time-distance inversions and coherent structure tracking of solar granules. Tracking provides two-dimensional horizontal flows on the solar surface, whereas the time-distance inversions estimate the full three-dimensional velocity flows in the shallow near-surface layers. Both techniques use Helioseismic and Magnetic Imager observations as input. We find good correlations between the various measurements resulting from the two techniques. Further, we find a good agreement between these measurements and the time-averaged Doppler line-of-sight velocity, and also perform sanity checks on the vertical flow that resulted from the three-dimensional time-distance inversion.

Licence prolongations of US nuclear power plants; Les prolongations de licence des centrales nucleaires americaines

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-04-01

Licences of US nuclear reactors were initially attributed for a 40 years duration. However, the vast majority of the reactors can benefit of a licence prolongation for a period of 20 years maximum. This article recalls first the procedure to follow for the licence prolongation demands (safety analysis, components aging, environmental impact statement), and then it makes a status of the accepted prolongations, of the demands under examination, and of the demands that should be presented in the next 5 years. (J.S.)

Coherent Control of Photoelectron Wavepacket Angular Interferograms

OpenAIRE

Hockett, Paul; Wollenhaupt, Matthias; Baumert, Thomas

2015-01-01

Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the cohere...

Subchondral insufficiency fracture of the knee: a non-traumatic injury with prolonged recovery time.

Science.gov (United States)

Gourlay, Margaret L; Renner, Jordan B; Spang, Jeffrey T; Rubin, Janet E

2015-06-08

Subchondral insufficiency fractures are non-traumatic fractures that occur immediately below the cartilage of a joint. Although low bone density may be present concurrently, it is not the underlying cause of subchondral insufficiency fractures in the majority of patients. Patients with subchondral insufficiency fracture characteristically have unremarkable plain radiographs, while MRI examination may reveal extensive bone marrow oedema and subchondral bone collapse. This article presents a 51-year-old postmenopausal woman, a physician, who had subchondral insufficiency fractures of the knee associated with prolonged standing during clinical work. She was treated with partial weight bearing on crutches until 14 months after the injury, viscosupplementation at 4 months to treat osteoarthritis and teriparatide treatment to improve bone healing at 7 months. By 26 months after the injury, she tolerated independent walking with a fabric knee support but still experienced mild posterolateral knee pain and numbness on prolonged standing. 2015 BMJ Publishing Group Ltd.

Prolonged bone marrow T1-relaxation in patients with polycythemia vera

DEFF Research Database (Denmark)

Jensen, K E; Grube, T; Thomsen, C

1988-01-01

In vitro as well as in vivo studies have shown prolonged T1 relaxation times in patients with acute leukemia. The mechanism behind this finding is not known. In order to evaluate if this was specific for leukemia we examined eight patients with polycythemia vera, representing a condition with a r......In vitro as well as in vivo studies have shown prolonged T1 relaxation times in patients with acute leukemia. The mechanism behind this finding is not known. In order to evaluate if this was specific for leukemia we examined eight patients with polycythemia vera, representing a condition...

Ultrafast optical responses of {beta}-carotene and lycopene probed by sub-20-fs time-resolved coherent spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Fujiwara, M.; Sugisaki, M. [CREST-JST and Department of Physics, Osaka City University, Osaka 558-8585 (Japan); Gall, A.; Robert, B. [CEA, Institut de Biologie et Technologies de Saclay, and CNRS, Gif-sur-Yvette F-91191 (France); Cogdell, R.J. [IBLS, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow G12 8QQ, Scotland (United Kingdom); Hashimoto, H., E-mail: hassy@sci.osaka-cu.ac.j [CREST-JST and Department of Physics, Osaka City University, Osaka 558-8585 (Japan)

2009-12-15

We investigate how structural distortions in carotenoid cause decoherences of its high-frequency vibrational modes by applying the sub-20-fs time-resolved transient grating spectroscopy to {beta}-carotene and lycopene. The results indicate that the C=C central stretching mode shows significant loss of coherence under the effects of the steric hindrance between {beta}-ionone ring and polyene backbone, whereas the other high-frequency modes do not show such dependency on the structural distortions.

Ultrafast optical responses of β-carotene and lycopene probed by sub-20-fs time-resolved coherent spectroscopy

International Nuclear Information System (INIS)

Fujiwara, M.; Sugisaki, M.; Gall, A.; Robert, B.; Cogdell, R.J.; Hashimoto, H.

2009-01-01

We investigate how structural distortions in carotenoid cause decoherences of its high-frequency vibrational modes by applying the sub-20-fs time-resolved transient grating spectroscopy to β-carotene and lycopene. The results indicate that the C=C central stretching mode shows significant loss of coherence under the effects of the steric hindrance between β-ionone ring and polyene backbone, whereas the other high-frequency modes do not show such dependency on the structural distortions.

Ways to Optimize Therapy of Prolonged Conjugation Jaundice in Infants

Directory of Open Access Journals (Sweden)

O.G. Shadrin

2015-09-01

Full Text Available The article is devoted to the optimization of the treatment of prolonged conjugation jaundice. Inclusion of ursodeoxycholic acid in the treatment of neonatal prolonged conjugation jaundice in a dose of 15–20 mg/kg of body mass per day increases the terms of regression of clinical and paraclinical signs of jaundice as much as 2 times and leads to cytolysis normalization. The preparation has a sufficient level of safety, there were not revealed side effects whilst its application.

Quality of drug label information on QT interval prolongation

DEFF Research Database (Denmark)

Warnier, Miriam J; Holtkamp, Frank A; Rutten, Frans H

2014-01-01

BACKGROUND: Information regarding QT-prolongation in the drug label may vary between products. This could lead to suboptimal risk minimization strategies. OBJECTIVE: To systematically assess the variation in the extent and content of information on QT prolongation in the summary of product......-prolongation'/'QT-prolongation') and the advice on cautionary measures pertaining to QT-prolongation in the label were examined, as well as their association. RESULTS: Of the 175 screened products, 44 contained information on QT in the SPC ('no QT-prolongation': 23%, 'unclear drug-QT association': 43%, 'possibly QT-prolongation': 16%, 'QT......-prolongation': 18%). 62% contained advices to act with caution in patients with additional risk factors for QT-prolongation. Products that more likely to have QT-prolonging properties according to the SPC provided more information on QT-prolongation in the SPC ('no prolongation': 10% and for the category 'QT...

Coherent Performance Analysis of the HJ-1-C Synthetic Aperture Radar

Directory of Open Access Journals (Sweden)

Li Hai-ying

2014-06-01

Full Text Available Synthetic Aperture Radar (SAR is a coherent imaging radar. Hence, coherence is critical in SAR imaging. In a coherent system, several sources can degrade performance. Based on the HJ-1-C SAR system implementation and sensor characteristics, this study evaluates the effect of frequency stability and pulse-to-pulse timing jitter on the SAR coherent performance. A stable crystal oscillator with short-term stability of 10×1.0−10 / 5 ms is used to generate the reference frequency by using a direct multiplier and divider. Azimuth ISLR degradation owing to the crystal oscillator phase noise is negligible. The standard deviation of the pulse-to-pulse timing jitter of HJ-1-C SAR is lower than 2ns (rms and the azimuth random phase error in the synthetic aperture time slightly degrades the side lobe of the azimuth impulse response. The mathematical expressions and simulation results are presented and suggest that the coherent performance of the HJ-1-C SAR system meets the requirements of synthetic aperture radar imaging.

Behavioral changes over time in post-traumatic stress disorder: Insights from a rat model of single prolonged stress.

Science.gov (United States)

Wu, Zhuoyun; Tian, Qing; Li, Feng; Gao, Junqiao; Liu, Yan; Mao, Meng; Liu, Jing; Wang, Shuyan; Li, Genmao; Ge, Dongyu; Mao, Yingqiu; Zhang, Wei; Liu, Zhaolan; Song, Yuehan

2016-03-01

Post-traumatic stress disorder (PTSD) is manifested as a persistent mental and emotional condition after potentially life-threatening events. Different animal models of PTSD have been developed for neuro-pathophysiology and pharmacological evaluations. A single prolonged stress (SPS) induced animal model has demonstrated to result in specific neuro-endocrinological dysregulation, and behavior abnormalities observed in PTSD. However, animal studies of PTSD have mostly been performed at one time point after SPS exposure. To better understand the development of PTSD-like behaviors in the SPS animal model, and to identify an optimal period of study, we examined depressive behavior, anxiety-like behavior, physical activity and body weight in SPS model rats for two weeks. Our results confirmed the SPS-induced PTSD-like behavior and physical activity observed in previous studies, and indicated that the most pronounced symptomatic behavior changes were observed on day 1 and 7 after SPS exposure, which may involve stress-induced acute hormone changes and unclear secondary neurobiological changes, respectively. These results provide a solid basis for further investigation into the neuro-pathophysiology of or neuropharmacology for PTSD using the SPS rat model. However, for chronic (pharmacological) studies longer than 7 days, a prolonged PTSD animal model should be developed, perhaps using enhanced stimulation. Copyright © 2016 Elsevier B.V. All rights reserved.

Time-varying Brain Potentials and Interhemispheric Coherences of Anterior and Posterior Regions during Repetitive Unimanual Finger Movements

Directory of Open Access Journals (Sweden)

Hsiao-Lung Chan

2007-06-01

Full Text Available Previous brain electrophysiological research has studied the interregionalconnectivity during the tapping task and found that inter-hemispheric alpha coherence wasmore significant under bimanual task conditions than that under unilateral conditions, butthe interregional connectivity situation in the unilateral tapping condition was not exploredclearly. We have designed a unilateral repetitive finger-tapping task to delineate the anteriorand posterior cortex contributions to unilateral finger movement. Sixteen right handedcollege students participated in this study. Event related potentials (ERPs and the strengthof event related coherence (ERCoh were analyzed to examine the antero-posterodominance of cortical activity in the phase of early visual process (75-120ms, pre-execution(175-260ms, execution (310-420ms and post-execution (420-620ms. Results showed thatthe occipital (Oz, O1 and O2, frontal (Fz, F3, and F4, fronto-central (Fz, Cz, F3 and C3,and parietal regions were the most pronounced in the early visual, pre-execution, execution,and post-execution phases, respectively. Moreover, among four inter-hemispheric pairs onlythe Coh (C3 and C4 was significantly correlated to reaction time (RT of tapping in theexecution phase. In conclusion, the aforementioned variability of electrophysiological data(ERPs and coherence and the change of antero-postero regional dominance with timereflect the relative importance of different mechanisms in different phases. The mechanismsof visual processing, motor planning, motor execution and feedback reward wereoperational, respectively.

Prolonging coherence in trapped ions

CSIR Research Space (South Africa)

Uys, H

2010-09-01

Full Text Available The authors study pulse sequences that dynamically decouple 9Be+ ions from their decohering environment. The noise environment the ions see is artificially synthesized to emulate a variety of physical systems. By incorporating measurement feedback...

Detecting multiple moving objects in crowded environments with coherent motion regions

Science.gov (United States)

Cheriyadat, Anil M.; Radke, Richard J.

2013-06-11

Coherent motion regions extend in time as well as space, enforcing consistency in detected objects over long time periods and making the algorithm robust to noisy or short point tracks. As a result of enforcing the constraint that selected coherent motion regions contain disjoint sets of tracks defined in a three-dimensional space including a time dimension. An algorithm operates directly on raw, unconditioned low-level feature point tracks, and minimizes a global measure of the coherent motion regions. At least one discrete moving object is identified in a time series of video images based on the trajectory similarity factors, which is a measure of a maximum distance between a pair of feature point tracks.

Partial coherence with application to the monotonicity problem of coherence involving skew information

Science.gov (United States)

Luo, Shunlong; Sun, Yuan

2017-08-01

Quantifications of coherence are intensively studied in the context of completely decoherent operations (i.e., von Neuamnn measurements, or equivalently, orthonormal bases) in recent years. Here we investigate partial coherence (i.e., coherence in the context of partially decoherent operations such as Lüders measurements). A bona fide measure of partial coherence is introduced. As an application, we address the monotonicity problem of K -coherence (a quantifier for coherence in terms of Wigner-Yanase skew information) [Girolami, Phys. Rev. Lett. 113, 170401 (2014), 10.1103/PhysRevLett.113.170401], which is introduced to realize a measure of coherence as axiomatized by Baumgratz, Cramer, and Plenio [Phys. Rev. Lett. 113, 140401 (2014), 10.1103/PhysRevLett.113.140401]. Since K -coherence fails to meet the necessary requirement of monotonicity under incoherent operations, it is desirable to remedy this monotonicity problem. We show that if we modify the original measure by taking skew information with respect to the spectral decomposition of an observable, rather than the observable itself, as a measure of coherence, then the problem disappears, and the resultant coherence measure satisfies the monotonicity. Some concrete examples are discussed and related open issues are indicated.

Measuring coherence with entanglement concurrence

Science.gov (United States)

Qi, Xianfei; Gao, Ting; Yan, Fengli

2017-07-01

Quantum coherence is a fundamental manifestation of the quantum superposition principle. Recently, Baumgratz et al (2014 Phys. Rev. Lett. 113 140401) presented a rigorous framework to quantify coherence from the view of theory of physical resource. Here we propose a new valid quantum coherence measure which is a convex roof measure, for a quantum system of arbitrary dimension, essentially using the generalized Gell-Mann matrices. Rigorous proof shows that the proposed coherence measure, coherence concurrence, fulfills all the requirements dictated by the resource theory of quantum coherence measures. Moreover, strong links between the resource frameworks of coherence concurrence and entanglement concurrence is derived, which shows that any degree of coherence with respect to some reference basis can be converted to entanglement via incoherent operations. Our work provides a clear quantitative and operational connection between coherence and entanglement based on two kinds of concurrence. This new coherence measure, coherence concurrence, may also be beneficial to the study of quantum coherence.

Primiparous women's preferences for care during a prolonged latent phase of labour.

Science.gov (United States)

Ängeby, Karin; Wilde-Larsson, Bodil; Hildingsson, Ingegerd; Sandin-Bojö, Ann-Kristin

2015-10-01

To investigate primiparous women's preferences for care during a prolonged latent phase of labour. A qualitative study based on focus groups and individual interviews and analysed with inductive content analysis. Sixteen primiparous women with a prolonged latent phase of labour >18 hours were interviewed in five focus groups (n = 11) or individually (n = 5). One main category emerged "Beyond normality - a need of individual adapted guidance in order to understand and manage an extended latent phase of labour" which covers the women's preferences during the prolonged latent phase. Five categories were generated from the data: "A welcoming manner and not being rejected", "Individually adapted care", "Important information which prepares for reality and coping", "Participation and need for feedback" and "Staying nearby the labour ward or being admitted for midwifery support". Women with a prolonged latent phase of labour sought to use their own resources, but their needs for professional support increased as time passed. A welcoming attitude from an available midwife during the latent phase created a feeling of security, and personally adapted care was perceived positively. Women with a prolonged latent phase of labour preferred woman-centred care. Midwives play an important role in supporting these women. Women's need for midwifery-support increases as the time spent in latent phase increases. Copyright © 2015 Elsevier B.V. All rights reserved.

Coupled Qubits for Next Generation Quantum Annealing: Improving Coherence

Science.gov (United States)

Weber, Steven; Samach, Gabriel; Hover, David; Rosenberg, Danna; Yoder, Jonilyn; Kim, David K.; Kerman, Andrew; Oliver, William D.

Quantum annealing is an optimization technique which potentially leverages quantum tunneling to enhance computational performance. Existing quantum annealers use superconducting flux qubits with short coherence times, limited primarily by the use of large persistent currents. Here, we examine an alternative approach, using flux qubits with smaller persistent currents and longer coherence times. We demonstrate tunable coupling, a basic building-block for quantum annealing, between two such qubits. Furthermore, we characterize qubit coherence as a function of coupler setting and investigate the effect of flux noise in the coupler loop on qubit coherence. Our results provide insight into the available design space for next-generation quantum annealers with improved coherence. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA) and by the Assistant Secretary of Defense for Research & Engineering under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

Optical Coherence Tomography (OCT for Time-Resolved Imaging of Alveolar Dynamics in Mechanically Ventilated Rats

Directory of Open Access Journals (Sweden)

Christian Schnabel

2017-03-01

Full Text Available Though artificial ventilation is an essential life-saving treatment, the mechanical behavior of lung tissue at the alveolar level is still unknown. Therefore, we need to understand the tissue response during artificial ventilation at this microscale in order to develop new and more protective ventilation methods. Optical coherence tomography (OCT combined with intravital microscopy (IVM is a promising tool for visualizing lung tissue dynamics with a high spatial and temporal resolution in uninterruptedly ventilated rats. We present a measurement setup using a custom-made animal ventilator and a gating technique for data acquisition of time-resolved sequences.

A real time multi-server multi-client coherent database for a new high voltage system

International Nuclear Information System (INIS)

Gorbics, M.; Green, M.

1995-01-01

A high voltage system has been designed to allow multiple users (clients) access to the database of measured values and settings. This database is actively maintained in real time for a given mainframe containing multiple modules each having their own database. With limited CPU nd memory resources the mainframe system provides a data coherency scheme for multiple clients which (1) allows the client to determine when and what values need to be updated, (2) allows for changes from one client to be detected by another client, and (3) does not depend on the mainframe system tracking client accesses

Population and coherence dynamics in light harvesting complex II (LH2).

Science.gov (United States)

Yeh, Shu-Hao; Zhu, Jing; Kais, Sabre

2012-08-28

The electronic excitation population and coherence dynamics in the chromophores of the photosynthetic light harvesting complex 2 (LH2) B850 ring from purple bacteria (Rhodopseudomonas acidophila) have been studied theoretically at both physiological and cryogenic temperatures. Similar to the well-studied Fenna-Matthews-Olson (FMO) protein, oscillations of the excitation population and coherence in the site basis are observed in LH2 by using a scaled hierarchical equation of motion approach. However, this oscillation time (300 fs) is much shorter compared to the FMO protein (650 fs) at cryogenic temperature. Both environment and high temperature are found to enhance the propagation speed of the exciton wave packet yet they shorten the coherence time and suppress the oscillation amplitude of coherence and the population. Our calculations show that a long-lived coherence between chromophore electronic excited states can exist in such a noisy biological environment.

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.

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.

Prolonged pregnancy: Methods, Causal Determinants and Outcome

DEFF Research Database (Denmark)

Olesen, Annette Wind

Summary Prolonged pregnancy, defined as a pregnancy with a gestational length of 294 days or more, is a frequent condition. It is associated with an increased risk of fetal and maternal complications. Little is known about the aetiology of prolonged pregnancy. The aims of the thesis were 1......) to study the incidence of prolonged pregnancy as a function of methods for determining gestational age; 2) to determine the risk of obstetrical and fetal complications in prolonged pregnancy; 3) to validate the self-reported gestational age in the National Birth Cohort; 4) to determine whether...... the risk of recurrence of prolonged pregnancy as a function of change in male partner and social conditions (IV). The National Birth Cohort provided data for the study on prenatal risk indicators of prolonged pregnancy in a follow-up design (V). The self-reported gestational ages from this database...

On the possibility of time-lapse ultrahigh-resolution optical coherence tomography for bladder cancer grading

Science.gov (United States)

Yuan, Zhijia; Chen, Bai; Ren, Hugang; Pan, Yingtian

2009-09-01

It has been recently demonstrated that the cellular details of bladder epithelium embedded in speckle noise can be uncovered with time-lapse ultrahigh-resolution optical coherence tomography (TL-uOCT) by proper time-lapse frame averaging that takes advantage of cellular micromotion in fresh biological tissue ex vivo. Here, spectral-domain 3-D TL-uOCT is reported to further improve the image fidelity, and new experimental evidence is presented to differentiate normal and cancerous nuclei of rodent bladder epithelia. Results of animal cancer study reveal that despite a slight overestimation (e.g., cancerous (e.g., high-grade DN''~13 μm) urothelia, which may potentially be very useful for enhancing the diagnosis of nonpapillary bladder cancer. More animal study is being conducted to examine the utility to differentiate hyperplasia, dysplasia, and carcinoma in situ.

Broadband demonstrations of true-time delay using linear sideband chirped programming and optical coherent transients

International Nuclear Information System (INIS)

Reibel, R.R.; Barber, Z.W.; Fischer, J.A.; Tian, M.; Babbitt, W.R.

2004-01-01

Linear sideband chirped (LSC) programming is introduced as a means of configuring spatial-spectral holographic gratings for optical coherent transient processors. Similar to linear frequency chirped programming, LSC programming allows the use of broadband integrated electro-optic phase modulators to produce chirps instead of using elaborate broadband chirped lasers. This approach has several advantages including the ability to use a stabilized laser for the optical carrier as well as stable, reproducible chirped optical signals when the modulator is driven digitally. Using LSC programming, we experimentally demonstrate broadband true-time delay as a proof of principle for the optical control of phased array radars. Here both cw phase modulated and binary phase shift keyed probe signals are true-time delayed with bandwidths of 1 GHz and delay resolutions better than 60 ps

Coherent Exciton Dynamics in GaAs-Based Semiconductor Structures

Science.gov (United States)

Colocci, M.; Bogani, F.; Ceccherini, S.; Gurioli, M.

We show that a very powerful tool in the investigation of the coherent exciton dynamics in semiconductors is provided by the study of the emitted light after resonant excitation from pairs of phase-locked femtosecond pulses. Under these conditions, not only the full dynamics of the coherent transients (dephasing times, quantum beat periods, etc.) can be obtained from linear experiments, but it can also be obtained a straightforward discrimination between the coherent or incoherent character of the emission by means of spectral filtering.

Prolonged CT urography in duplex kidney.

Science.gov (United States)

Gong, Honghan; Gao, Lei; Dai, Xi-Jian; Zhou, Fuqing; Zhang, Ning; Zeng, Xianjun; Jiang, Jian; He, Laichang

2016-05-13

Duplex kidney is a common anomaly that is frequently associated with multiple complications. Typical computed tomography urography (CTU) includes four phases (unenhanced, arterial, parenchymal and excretory) and has been suggested to considerably aid in the duplex kidney diagnosi. Unfortunately, regarding duplex kidney with prolonged dilatation, the affected parenchyma and tortuous ureters demonstrate a lack of or delayed excretory opacification. We used prolonged-delay CTU, which consists of another prolonged-delay phase (1- to 72-h delay; mean delay: 24 h) to opacify the duplicated ureters and affected parenchyma. Seventeen patients (9 males and 8 females; age range: 2.5-56 y; mean age: 40.4 y) with duplex kidney were included in this study. Unenhanced scans did not find typical characteristics of duplex kidney, except for irregular perirenal morphology. Duplex kidney could not be confirmed on typical four-phase CTU, whereas it could be easily diagnosed in axial and CT-3D reconstruction using prolonged CTU (prolonged-delay phase). Between January 2005 and October 2010, in this review board-approved study (with waived informed consent), 17 patients (9 males and 8 females; age range: 2.5 ~ 56 y; mean age: 40.4 y) with suspicious duplex kidney underwent prolonged CTU to opacify the duplicated ureters and confirm the diagnosis. Our results suggest the validity of prolonged CTU to aid in the evaluation of the function of the affected parenchyma and in the demonstration of urinary tract malformations.

Time-Resolved Speckle Analysis: A New Approach to Coherence and Dephasing of Optical Excitations in Solids

DEFF Research Database (Denmark)

Langbein, Wolfgang Werner; Hvam, Jørn Märcher; Zimmermann, R.

1999-01-01

). This method determines the decays of intensity and coherence separately, thus distinguishing lifetime from pure dephasing. The secondary emission of excitons in semiconductor quantum wells is investigated. Here the combination of static disorder and inelastic scattering leads to a partially coherent emission....... The temperature dependence is well explained by phonon scattering....

Regulatory risk coherence

International Nuclear Information System (INIS)

Remick, F.J.

1992-01-01

As one of the most progressive users of risk assessment in decision making, the US Nuclear Regulatory Commission (NRC) is in a position to play an important role in influencing the development of standard government wide policies for the application of risk assessment in decision making. The NRC, with the support of the nuclear industry, should use the opportunity provided by its experience with risk assessment to actively encourage the adoption of standard national and international health-based safety goals and at the same time accelerate its own efforts to implement the safety goals it has already developed for itself. There are signs of increased recognition of the need for consistency and coherence in the application of risk assessment in government decision making. The NRC and the nuclear industry have recently taken a great step toward establishing a consistant and coherent risk assessment-based culture in the US nuclear industry. As a result of Generic Letter 88-20, which asks each commercial nuclear power plant licensee to perform an individual plant examination by September 1992, for the first time a risk assessment characterizing initiating events in each plant will exist

Coherent Control of Ground State NaK Molecules

Science.gov (United States)

Yan, Zoe; Park, Jee Woo; Loh, Huanqian; Will, Sebastian; Zwierlein, Martin

2016-05-01

Ultracold dipolar molecules exhibit anisotropic, tunable, long-range interactions, making them attractive for the study of novel states of matter and quantum information processing. We demonstrate the creation and control of 23 Na40 K molecules in their rovibronic and hyperfine ground state. By applying microwaves, we drive coherent Rabi oscillations of spin-polarized molecules between the rotational ground state (J=0) and J=1. The control afforded by microwave manipulation allows us to pursue engineered dipolar interactions via microwave dressing. By driving a two-photon transition, we are also able to observe Ramsey fringes between different J=0 hyperfine states, with coherence times as long as 0.5s. The realization of long coherence times between different molecular states is crucial for applications in quantum information processing. NSF, AFOSR- MURI, Alfred P. Sloan Foundation, DARPA-OLE

Dynamic coherence in excitonic molecular complexes under various excitation conditions

Energy Technology Data Exchange (ETDEWEB)

Chenu, Aurélia; Malý, Pavel; Mančal, Tomáš, E-mail: mancal@karlov.mff.cuni.cz

2014-08-17

Highlights: • Dynamic coherence does not improve energy transfer efficiency in natural conditions. • Photo-induced quantum jumps are discussed in classical context. • Natural time scale of a light excitation event is identified. • Coherence in FMO complex averages out under excitation by neighboring antenna. • This result is valid even in absence of dissipation. - Abstract: We investigate the relevance of dynamic quantum coherence in the energy transfer efficiency of molecular aggregates. We derive the time evolution of the density matrix for an open quantum system excited by light or by a neighboring antenna. Unlike in the classical case, the quantum description does not allow for a formal decomposition of the dynamics into sudden jumps in an observable quantity – an expectation value. Rather, there is a natural finite time-scale associated with the excitation process. We propose a simple experiment to test the influence of this time scale on the yield of photosynthesis. We demonstrate, using typical parameters of the Fenna–Matthews–Olson (FMO) complex and a typical energy transfer rate from the chlorosome baseplate, that dynamic coherences are averaged out in the complex even when the FMO model is completely free of all dissipation and dephasing.

Coherent structures in tokamak plasmas workshop: Proceedings

International Nuclear Information System (INIS)

Koniges, A.E.; Craddock, G.G.

1992-08-01

Coherent structures have the potential to impact a variety of theoretical and experimental aspects of tokamak plasma confinement. This includes the basic processes controlling plasma transport, propagation and efficiency of external mechanisms such as wave heating and the accuracy of plasma diagnostics. While the role of coherent structures in fluid dynamics is better understood, this is a new topic for consideration by plasma physicists. This informal workshop arose out of the need to identify the magnitude of structures in tokamaks and in doing so, to bring together for the first time the surprisingly large number of plasma researchers currently involved in work relating to coherent structures. The primary purpose of the workshop, in addition to the dissemination of information, was to develop formal and informal collaborations, set the stage for future formation of a coherent structures working group or focus area under the heading of the Tokamak Transport Task Force, and to evaluate the need for future workshops on coherent structures. The workshop was concentrated in four basic areas with a keynote talk in each area as well as 10 additional presentations. The issues of discussion in each of these areas was as follows: Theory - Develop a definition of structures and coherent as it applies to plasmas. Experiment - Review current experiments looking for structures in tokamaks, discuss experimental procedures for finding structures, discuss new experiments and techniques. Fluids - Determine how best to utilize the resource of information available from the fluids community both on the theoretical and experimental issues pertaining to coherent structures in plasmas. Computation - Discuss computational aspects of studying coherent structures in plasmas as they relate to both experimental detection and theoretical modeling

Multiple coherence resonances and synchronization transitions by time delay in adaptive scale-free neuronal networks with spike-timing-dependent plasticity

International Nuclear Information System (INIS)

Xie, Huijuan; Gong, Yubing

2017-01-01

In this paper, we numerically study the effect of spike-timing-dependent plasticity (STDP) on multiple coherence resonances (MCR) and synchronization transitions (ST) induced by time delay in adaptive scale-free Hodgkin–Huxley neuronal networks. It is found that STDP has a big influence on MCR and ST induced by time delay and on the effect of network average degree on the MCR and ST. MCR is enhanced or suppressed as the adjusting rate A p of STDP decreases or increases, and there is optimal A p by which ST becomes strongest. As network average degree 〈k〉 increases, ST is enhanced and there is optimal 〈k〉 at which MCR becomes strongest. Moreover, for a larger A p value, ST is enhanced more rapidly with increasing 〈k〉 and the optimal 〈k〉 for MCR increases. These results show that STDP can either enhance or suppress MCR, and there is optimal STDP that can most strongly enhance ST induced by time delay in the adaptive neuronal networks. These findings could find potential implication for the information processing and transmission in neural systems.

Temporal and transverse coherence of self-amplified spontaneous emission

International Nuclear Information System (INIS)

Kim, K.J.

1997-06-01

The authors review the coherence properties of the self-amplified spontaneous emission (SASE). Temporally, SASE is similar to the spontaneous undulator radiation except that the spectral bandwidth is about ten times narrower compared with typical undulator radiation. The situation is quite different in the transverse dimension, where SASE is fully coherent

Wavelet coherence analysis of dynamic cerebral autoregulation in neonatal hypoxic–ischemic encephalopathy

Directory of Open Access Journals (Sweden)

Fenghua Tian

2016-01-01

Full Text Available Cerebral autoregulation represents the physiological mechanisms that keep brain perfusion relatively constant in the face of changes in blood pressure and thus plays an essential role in normal brain function. This study assessed cerebral autoregulation in nine newborns with moderate-to-severe hypoxic–ischemic encephalopathy (HIE. These neonates received hypothermic therapy during the first 72 h of life while mean arterial pressure (MAP and cerebral tissue oxygenation saturation (SctO2 were continuously recorded. Wavelet coherence analysis, which is a time-frequency domain approach, was used to characterize the dynamic relationship between spontaneous oscillations in MAP and SctO2. Wavelet-based metrics of phase, coherence and gain were derived for quantitative evaluation of cerebral autoregulation. We found cerebral autoregulation in neonates with HIE was time-scale-dependent in nature. Specifically, the spontaneous changes in MAP and SctO2 had in-phase coherence at time scales of less than 80 min (<0.0002 Hz in frequency, whereas they showed anti-phase coherence at time scales of around 2.5 h (~0.0001 Hz in frequency. Both the in-phase and anti-phase coherence appeared to be related to worse clinical outcomes. These findings suggest the potential clinical use of wavelet coherence analysis to assess dynamic cerebral autoregulation in neonatal HIE during hypothermia.

Enhanced performance for differential detection in coherent Brillouin optical time-domain analysis sensors

Science.gov (United States)

Shao, Liyang; Zhang, Yunpeng; Li, Zonglei; Zhang, Zhiyong; Zou, Xihua; Luo, Bin; Pan, Wei; Yan, Lianshan

2016-11-01

Logarithmic detectors (LogDs) have been used in coherent Brillouin optical time-domain analysis (BOTDA) sensors to reduce the effect of phase fluctuation, demodulation complexities, and measurement time. However, because of the inherent properties of LogDs, a DC component at the level of hundreds of millivolts that prohibits high-gain signal amplification (SA) could be generated, resulting in unacceptable data acquisition (DAQ) inaccuracies and decoding errors in the process of prototype integration. By generating a reference light at a level similar to the probe light, differential detection can be applied to remove the DC component automatically using a differential amplifier before the DAQ process. Therefore, high-gain SA can be employed to reduce quantization errors. The signal-to-noise ratio of the weak Brillouin gain signal is improved from ˜11.5 to ˜21.8 dB. A BOTDA prototype is implemented based on the proposed scheme. The experimental results show that the measurement accuracy of the Brillouin frequency shift (BFS) is improved from ±1.9 to ±0.8 MHz at the end of a 40-km sensing fiber.

Physiological coherence in healthy volunteers during laboratory-induced stress and controlled breathing.

Science.gov (United States)

Mejía-Mejía, Elisa; Torres, Robinson; Restrepo, Diana

2018-06-01

Physiological coherence has been related with a general sense of well-being and improvements in health and physical, social, and cognitive performance. The aim of this study was to evaluate the relationship between acute stress, controlled breathing, and physiological coherence, and the degree of body systems synchronization during a coherence-generation exercise. Thirty-four university employees were evaluated during a 20-min test consisting of four stages of 5-min duration each, during which basal measurements were obtained (Stage 1), acute stress was induced using validated mental stressors (Stroop test and mental arithmetic task, during Stage 2 and 3, respectively), and coherence states were generated using a controlled breathing technique (Stage 4). Physiological coherence and cardiorespiratory synchronization were assessed during each stage from heart rate variability, pulse transit time, and respiration. Coherence measurements derived from the three analyzed variables increased during controlled respiration. Moreover, signals synchronized during the controlled breathing stage, implying a cardiorespiratory synchronization was achieved by most participants. Hence, physiological coherence and cardiopulmonary synchronization, which could lead to improvements in health and better life quality, can be achieved using slow, controlled breathing exercises. Meanwhile, coherence measured during basal state and stressful situations did not show relevant differences using heart rate variability and pulse transit time. More studies are needed to evaluate the ability of coherence ratio to reflect acute stress. © 2017 Society for Psychophysiological Research.

Quantum coherence: Reciprocity and distribution

Energy Technology Data Exchange (ETDEWEB)

Kumar, Asutosh, E-mail: asukumar@hri.res.in [Harish-Chandra Research Institute, Allahabad-211019 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India)

2017-03-18

Quantum coherence is the outcome of the superposition principle. Recently, it has been theorized as a quantum resource, and is the premise of quantum correlations in multipartite systems. It is therefore interesting to study the coherence content and its distribution in a multipartite quantum system. In this work, we show analytically as well as numerically the reciprocity between coherence and mixedness of a quantum state. We find that this trade-off is a general feature in the sense that it is true for large spectra of measures of coherence and of mixedness. We also study the distribution of coherence in multipartite systems by looking at monogamy-type relation–which we refer to as additivity relation–between coherences of different parts of the system. We show that for the Dicke states, while the normalized measures of coherence violate the additivity relation, the unnormalized ones satisfy the same. - Highlights: • Quantum coherence. • Reciprocity between quantum coherence and mixedness. • Distribution of quantum coherence in multipartite quantum systems. • Additivity relation for distribution of quantum coherence in Dicke and “X” states.

Remote wind sensing with a CW diode laser lidar beyond the coherence regime

DEFF Research Database (Denmark)

Hu, Qi; Rodrigo, Peter John; Pedersen, Christian

2014-01-01

We experimentally demonstrate for the first time (to our knowledge) a coherent CW lidar system capable of wind speed measurement at a probing distance beyond the coherence regime of the light source. A side-by-side wind measurement was conducted on the field using two lidar systems with identical...... optical designs but different laser linewidths. While one system was operating within the coherence regime, the other was measuring at least 2.4 times the coherence range. The probing distance of both lidars is 85 m and the radial wind speed correlation was measured to be r2=0.965 between the two lidars...

Coherence techniques at extreme ultraviolet wavelengths

Energy Technology Data Exchange (ETDEWEB)

Chang, Chang [Univ. of California, Berkeley, CA (United States)

2002-01-01

The renaissance of Extreme Ultraviolet (EUV) and soft x-ray (SXR) optics in recent years is mainly driven by the desire of printing and observing ever smaller features, as in lithography and microscopy. This attribute is complemented by the unique opportunity for element specific identification presented by the large number of atomic resonances, essentially for all materials in this range of photon energies. Together, these have driven the need for new short-wavelength radiation sources (e.g. third generation synchrotron radiation facilities), and novel optical components, that in turn permit new research in areas that have not yet been fully explored. This dissertation is directed towards advancing this new field by contributing to the characterization of spatial coherence properties of undulator radiation and, for the first time, introducing Fourier optical elements to this short-wavelength spectral region. The first experiment in this dissertation uses the Thompson-Wolf two-pinhole method to characterize the spatial coherence properties of the undulator radiation at Beamline 12 of the Advanced Light Source. High spatial coherence EUV radiation is demonstrated with appropriate spatial filtering. The effects of small vertical source size and beamline apertures are observed. The difference in the measured horizontal and vertical coherence profile evokes further theoretical studies on coherence propagation of an EUV undulator beamline. A numerical simulation based on the Huygens-Fresnel principle is performed.

[Brain function recovery after prolonged posttraumatic coma].

Science.gov (United States)

Klimash, A V; Zhanaidarov, Z S

2016-01-01

To explore the characteristics of brain function recovery in patients after prolonged posttraumatic coma and with long-unconscious states. Eighty-seven patients after prolonged posttraumatic coma were followed-up for two years. An analysis of a clinical/neurological picture after a prolonged episode of coma was based on the dynamics of vital functions, neurological status and patient's reactions to external stimuli. Based on the dynamics of the clinical/neurological picture that shows the recovery of functions of the certain brain areas, three stages of brain function recovery after a prolonged episode of coma were singled out: brain stem areas, diencephalic areas and telencephalic areas. These functional/anatomic areas of brain function recovery after prolonged coma were compared to the present classifications.

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.

Study on the Fluid Flow Characteristics of Coherent Jets with CO2 and O2 Mixed Injection in Electric Arc Furnace Steelmaking Processes

Science.gov (United States)

Wei, Guangsheng; Zhu, Rong; Wu, Xuetao; Yang, Lingzhi; Dong, Kai; Cheng, Ting; Tang, Tianping

2018-06-01

As an efficient oxygen supplying technology, coherent jets are widely applied in electric arc furnace (EAF) steelmaking processes to strengthen chemical energy input, speed up smelting rhythm, and promote the uniformity of molten bath temperature and compositions. Recently, the coherent jet with CO2 and O2 mixed injection (COMI) was proposed and demonstrated great application potentiality in reducing the dust production in EAF steelmaking. In the present study, based on the eddy dissipation concept model, a computational fluid dynamics model of coherent jets with COMI was built with the overall and detailed chemical kinetic mechanisms (GRI-Mech 3.0). Compared with one-step combustion reaction, GRI-Mech 3.0 consists of 325 elementary reactions with 53 components and can predict more accurate results. The numerical simulation results were validated by the combustion experiment data. The jet behavior and the fluid flow characteristics of coherent jets with COMI under 298 K and 1700 K (25 °C and 1427 °C) were studied and the results showed that for coherent jets with COMI, the chemical effect of CO2 significantly weakened the shrouding combustion reactions of CH4 and the relative importance of the chemical effect of CO2 increases with CO2 concentration increasing. The potential core length of coherent jet decreases with the volume fraction of CO2 increasing. Moreover, it also can be found that the potential core length of coherent jets was prolonged with higher ambient temperature.

Study on the Fluid Flow Characteristics of Coherent Jets with CO2 and O2 Mixed Injection in Electric Arc Furnace Steelmaking Processes

Science.gov (United States)

Wei, Guangsheng; Zhu, Rong; Wu, Xuetao; Yang, Lingzhi; Dong, Kai; Cheng, Ting; Tang, Tianping

2018-03-01

As an efficient oxygen supplying technology, coherent jets are widely applied in electric arc furnace (EAF) steelmaking processes to strengthen chemical energy input, speed up smelting rhythm, and promote the uniformity of molten bath temperature and compositions. Recently, the coherent jet with CO2 and O2 mixed injection (COMI) was proposed and demonstrated great application potentiality in reducing the dust production in EAF steelmaking. In the present study, based on the eddy dissipation concept model, a computational fluid dynamics model of coherent jets with COMI was built with the overall and detailed chemical kinetic mechanisms (GRI-Mech 3.0). Compared with one-step combustion reaction, GRI-Mech 3.0 consists of 325 elementary reactions with 53 components and can predict more accurate results. The numerical simulation results were validated by the combustion experiment data. The jet behavior and the fluid flow characteristics of coherent jets with COMI under 298 K and 1700 K (25 °C and 1427 °C) were studied and the results showed that for coherent jets with COMI, the chemical effect of CO2 significantly weakened the shrouding combustion reactions of CH4 and the relative importance of the chemical effect of CO2 increases with CO2 concentration increasing. The potential core length of coherent jet decreases with the volume fraction of CO2 increasing. Moreover, it also can be found that the potential core length of coherent jets was prolonged with higher ambient temperature.

3D wide field-of-view Gabor-domain optical coherence microscopy advancing real-time in-vivo imaging and metrology

Science.gov (United States)

Canavesi, Cristina; Cogliati, Andrea; Hayes, Adam; Tankam, Patrice; Santhanam, Anand; Rolland, Jannick P.

2017-02-01

Real-time volumetric high-definition wide-field-of-view in-vivo cellular imaging requires micron-scale resolution in 3D. Compactness of the handheld device and distortion-free images with cellular resolution are also critically required for onsite use in clinical applications. By integrating a custom liquid lens-based microscope and a dual-axis MEMS scanner in a compact handheld probe, Gabor-domain optical coherence microscopy (GD-OCM) breaks the lateral resolution limit of optical coherence tomography through depth, overcoming the tradeoff between numerical aperture and depth of focus, enabling advances in biotechnology. Furthermore, distortion-free imaging with no post-processing is achieved with a compact, lightweight handheld MEMS scanner that obtained a 12-fold reduction in volume and 17-fold reduction in weight over a previous dual-mirror galvanometer-based scanner. Approaching the holy grail of medical imaging - noninvasive real-time imaging with histologic resolution - GD-OCM demonstrates invariant resolution of 2 μm throughout a volume of 1 x 1 x 0.6 mm3, acquired and visualized in less than 2 minutes with parallel processing on graphics processing units. Results on the metrology of manufactured materials and imaging of human tissue with GD-OCM are presented.

Influence of prolonged cold ischemia in renal transplantation.

NARCIS (Netherlands)

Vliet, J.A. van der; Warle, M.C.; Cheung, C.L.; Teerenstra, S.; Hoitsma, A.J.

2011-01-01

van der Vliet JA, Warle MC, Cheung CLS, Teerenstra S, Hoitsma AJ. Influence of prolonged cold ischemia in renal transplantation. Clin Transplant 2011: 25: E612-E616. (c) 2011 John Wiley & Sons A/S. Abstract: Aim: To determine to what extent current cold ischemia times (CITs) affect the results of

[Pathophysiology of prolonged hypokinesia].

Science.gov (United States)

Kovalenko, E A

1976-01-01

Hypokinesia is an important problem in modern medicine. In the pathogenetic effect of prolonged hypokinesia the main etiological factor is diminished motor activity; of major importance are disorders in the energy and plastic metabolism which affect the muscle system; the contributing factors are cardiovascular deconditioning and orthostatic intolerance. This is attributed to a decreased oxygen supply and eliminated hydrostatic influences during a prolonged recumbency. Blood redistribution in the vascular bed is related to the Gauer-Henry reflex and subsequent changes in the fluid-electrolyte balance. Decreased load on the bone system induces changes in the protein-phosphate-calcium metabolism, diminished bone density and increased calcium content in the blood and urine. Changes in the calcium metabolism are systemic. The activity of the higher nervous system and reflex functions is lowered. Changes in the function of the autonomic nervous system which include a noticeable decline of its adaptive-trophic role as a result of the decrease of afferent and efferent impulsation are of great importance. Changes in the hormonal function involve a peculiar stress-reaction which develops at an early stage of hypokinesia as a response to an unusual situation. Prolonged hypokinesia may result in a disturbed function of the pituitary-adrenal system. It is assumed that prolonged hypokinesia may induce a specific disease of hypokinesia during which man cannot lead a normal mode of life and work.

Coherent control of quantum dots

DEFF Research Database (Denmark)

Johansen, Jeppe; Lodahl, Peter; Hvam, Jørn Märcher

In recent years much effort has been devoted to the use of semiconductor quantum dotsystems as building blocks for solid-state-based quantum logic devices. One importantparameter for such devices is the coherence time, which determines the number ofpossible quantum operations. From earlier...

Coherent synchrotron radiation by an electron linear accelerator

International Nuclear Information System (INIS)

Nakazato, T.; Oyamada, M.; Niimura, N.

1990-01-01

Coherent effects in synchrotron radiation (SR) have been observed for the first time from 180 MeV short electron bunches of 1.7 mm using the Tohoku 300 MeV Linac. The intensity of the coherent SR was about 10 5 times as strong as that of incoherent SR at wavelengths of 0.33 to 2.0 mm. This enhancement factor roughly corresponds to the number of electrons in a bunch. The SR intensity showed a quadratic dependence on the electron beam current. The radiation was mainly polarized in the orbital plane. The possibility of induced rf in a vacuum chamber was excluded experimentally. An electron linear accelerator will be applied to a strong light source from infrared to millimeter wavelengths instead of the storage rings. The bunch length of shorter than 1 mm can be observed by the spectrum measurement of coherent SR. (author)

Self-Mixing Demodulation for Coherent Phase-Sensitive OTDR System

Directory of Open Access Journals (Sweden)

Haijun He

2016-05-01

Full Text Available Phase-sensitive optical time domain reflectometry (Ф-OTDR attracts much attention due to its capability of telling the type and position of an intrusion simultaneously. In recent decades, coherent Ф-OTDR has been demonstrated to realize long-distance detection. For coherent Ф-OTDR, there are three typical demodulation schemes in the reported studies. However, they still cannot realize real-time monitoring to satisfy practical demands. A simple and effective demodulation method based on self-mixing has been put forward to demodulate the beat signal in coherent Ф-OTDR. It not only saves a local electrical oscillator and frequency locked loop, but also demodulates the beat signal without residual frequency. Several vibrations with different frequency were separately applied at the same location of a 42.5 km fiber. The spatial resolution of 10 m and frequency response range from 8 Hz to 980 Hz have been achieved. The precise location with signal-to-noise ratio of 21.4 dB and broadband measurement demonstrate the self-mixing scheme can demodulate the coherent Ф-OTDR signal effectively.

Measurement of the spatial coherence of a soft x-ray laser

International Nuclear Information System (INIS)

Trebes, J.E.; Mrowka, S.; London, R.A.; Barbee, T.W.; Carter, M.R.; MacGowan, B.J.; Matthews, D.L.; Da Silva, L.B.; Stone, G.F.; Feit, M.D.; Nugent, K.A.

1991-01-01

The spatial coherence of a neon-like selenium x-ray laser operating at 206 and 210 Angstroems has been measured using a technique based on partially coherent x-ray diffraction. The time integrated spatial coherence of the selenium x-ray laser was determined to be equivalent to that of a quasi-monochromatic spatially incoherent disk source whose diameter is comparable to the line focus of the visible light laser pumping the x-ray laser. The spatial coherence was improved by narrowing the line focus width. 20 refs., 4 figs

Coherence in Magnetic Quantum Tunneling

Science.gov (United States)

Fernandez, Julio F.

2001-03-01

Crystals of single molecule magnets such as Mn_12 and Fe8 behave at low temperatures as a collection of independent spins. Magnetic anisotropy barriers slow down spin-flip processes. Their rate Γ becomes temperature independent at sufficiently low temperature. Quantum tunneling (QT) accounts for this behavior. Currently, spin QT in Mn_12 and Fe8 is assumed to proceed as an incoherent sum of small probability increments that occur whenever a bias field h(t) (arising from hyperfine interactions with nuclear spins) that varies with time t becomes sufficiently small, as in Landau-Zener transitions. Within a two-state model, we study the behavior of a suitably defined coherence time τ_φ and compare it with the correlation time τh for h(t). It turns out that τ_φ >τ_h, when τ_hδ h < hbar, where δ h is the rms deviation of h. We show what effect such coherence has on Γ. Its dependence on a static longitudinal applied field Hz is drastically affected. There is however no effect if the field is swept through resonance.

Analysis of detection limit to time-resolved coherent anti-Stokes Raman scattering nanoscopy

International Nuclear Information System (INIS)

Liu Wei; Liu Shuang-Long; Chen Dan-Ni; Niu Han-Ben

2014-01-01

In the implementation of CARS nanoscopy, signal strength decreases with focal volume size decreasing. A crucial problem that remains to be solved is whether the reduced signal generated in the suppressed focal volume can be detected. Here reported is a theoretical analysis of detection limit (DL) to time-resolved CARS (T-CARS) nanoscopy based on our proposed additional probe-beam-induced phonon depletion (APIPD) method for the low concentration samples. In order to acquire a detailed shot-noise limited signal-to-noise (SNR) and the involved parameters to evaluate DL, the T-CARS process is described with full quantum theory to estimate the extreme power density levels of the pump and Stokes beams determined by saturation behavior of coherent phonons, which are both actually on the order of ∼ 10 9 W/cm 2 . When the pump and Stokes intensities reach such values and the total intensity of the excitation beams arrives at a maximum tolerable by most biological samples in a certain suppressed focal volume (40-nm suppressed focal scale in APIPD method), the DL correspondingly varies with exposure time, for example, DL values are 10 3 and 10 2 when exposure times are 20 ms and 200 ms respectively. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Nanosecond retinal structure changes in K-590 during the room-temperature bacteriorhodopsin photocycle: picosecond time-resolved coherent anti-stokes Raman spectroscopy

OpenAIRE

Weidlich, O.; Ujj, L.; Jäger, F.; Atkinson, G.H.

1997-01-01

Time-resolved vibrational spectra are used to elucidate the structural changes in the retinal chromophore within the K-590 intermediate that precedes the formation of the L-550 intermediate in the room-temperature (RT) bacteriorhodopsin (BR) photocycle. Measured by picosecond time-resolved coherent anti-Stokes Raman scattering (PTR/CARS), these vibrational data are recorded within the 750 cm-1 to 1720 cm-1 spectral region and with time delays of 50-260 ns after the RT/BR photocycle is optical...

QT Prolongation due to Graves’ Disease

Directory of Open Access Journals (Sweden)

Zain Kulairi

2017-01-01

Full Text Available Hyperthyroidism is a highly prevalent disease affecting over 4 million people in the US. The disease is associated with many cardiac complications including atrial fibrillation and also less commonly with ventricular tachycardia and fibrillation. Many cardiac pathologies have been extensively studied; however, the relationship between hyperthyroidism and rate of ventricular repolarization manifesting as a prolonged QTc interval is not well known. Prolonged QTc interval regardless of thyroid status is a risk factor for cardiovascular mortality and life-threatening ventricular arrhythmia. The mechanism regarding the prolongation of the QT interval in a hyperthyroid patient has not been extensively investigated although its clinical implications are relevant. Herein, we describe a case of prolonged QTc in a patient who presented with signs of hyperthyroidism that was corrected with return to euthyroid status.

Remote wind sensing with a CW diode laser lidar beyond the coherence regime.

Science.gov (United States)

Hu, Qi; Rodrigo, Peter John; Pedersen, Christian

2014-08-15

We experimentally demonstrate for the first time (to our knowledge) a coherent CW lidar system capable of wind speed measurement at a probing distance beyond the coherence regime of the light source. A side-by-side wind measurement was conducted on the field using two lidar systems with identical optical designs but different laser linewidths. While one system was operating within the coherence regime, the other was measuring at least 2.4 times the coherence range. The probing distance of both lidars is 85 m and the radial wind speed correlation was measured to be r2=0.965 between the two lidars at a sampling rate of 2 Hz. Based on our experimental results, we describe a practical guideline for designing a wind lidar operating beyond the coherence regime.

Ordering states with various coherence measures

Science.gov (United States)

Yang, Long-Mei; Chen, Bin; Fei, Shao-Ming; Wang, Zhi-Xi

2018-04-01

Quantum coherence is one of the most significant theories in quantum physics. Ordering states with various coherence measures is an intriguing task in quantification theory of coherence. In this paper, we study this problem by use of four important coherence measures—the l_1 norm of coherence, the relative entropy of coherence, the geometric measure of coherence and the modified trace distance measure of coherence. We show that each pair of these measures give a different ordering of qudit states when d≥3. However, for single-qubit states, the l_1 norm of coherence and the geometric coherence provide the same ordering. We also show that the relative entropy of coherence and the geometric coherence give a different ordering for single-qubit states. Then we partially answer the open question proposed in Liu et al. (Quantum Inf Process 15:4189, 2016) whether all the coherence measures give a different ordering of states.

Atom lasers, coherent states, and coherence II. Maximally robust ensembles of pure states

International Nuclear Information System (INIS)

Wiseman, H.M.; Vaccaro, John A.

2002-01-01

As discussed in the preceding paper [Wiseman and Vaccaro, preceding paper, Phys. Rev. A 65, 043605 (2002)], the stationary state of an optical or atom laser far above threshold is a mixture of coherent field states with random phase, or, equivalently, a Poissonian mixture of number states. We are interested in which, if either, of these descriptions of ρ ss as a stationary ensemble of pure states, is more natural. In the preceding paper we concentrated upon the question of whether descriptions such as these are physically realizable (PR). In this paper we investigate another relevant aspect of these ensembles, their robustness. A robust ensemble is one for which the pure states that comprise it survive relatively unchanged for a long time under the system evolution. We determine numerically the most robust ensembles as a function of the parameters in the laser model: the self-energy χ of the bosons in the laser mode, and the excess phase noise ν. We find that these most robust ensembles are PR ensembles, or similar to PR ensembles, for all values of these parameters. In the ideal laser limit (ν=χ=0), the most robust states are coherent states. As the phase noise or phase dispersion is increased through ν or the self-interaction of the bosons χ, respectively, the most robust states become more and more amplitude squeezed. We find scaling laws for these states, and give analytical derivations for them. As the phase diffusion or dispersion becomes so large that the laser output is no longer quantum coherent, the most robust states become so squeezed that they cease to have a well-defined coherent amplitude. That is, the quantum coherence of the laser output is manifest in the most robust PR ensemble being an ensemble of states with a well-defined coherent amplitude. This lends support to our approach of regarding robust PR ensembles as the most natural description of the state of the laser mode. It also has interesting implications for atom lasers in particular

Coherent states of quantum systems. [Hamiltonians, variable magnetic field, adiabatic approximation

Energy Technology Data Exchange (ETDEWEB)

Trifonov, D A

1975-01-01

Time-evolution of coherent states and uncertainty relations for quantum systems are considered as well as the relation between the various types of coherent states. The most general form of the Hamiltonians that keep the uncertainty products at a minimum is found using the coherent states. The minimum uncertainty packets are shown to be coherent states of the type nonstationary-system coherent states. Two specific systems, namely that of a generalized N-dimensional oscillator and that of a charged particle moving in a variable magnetic field, are treated as examples. The adiabatic approximation to the uncertainty products for these systems is also discussed and the minimality is found to be retained with an exponential accuracy.

A fast BDD algorithm for large coherent fault trees analysis

International Nuclear Information System (INIS)

Jung, Woo Sik; Han, Sang Hoon; Ha, Jaejoo

2004-01-01

Although a binary decision diagram (BDD) algorithm has been tried to solve large fault trees until quite recently, they are not efficiently solved in a short time since the size of a BDD structure exponentially increases according to the number of variables. Furthermore, the truncation of If-Then-Else (ITE) connectives by the probability or size limit and the subsuming to delete subsets could not be directly applied to the intermediate BDD structure under construction. This is the motivation for this work. This paper presents an efficient BDD algorithm for large coherent systems (coherent BDD algorithm) by which the truncation and subsuming could be performed in the progress of the construction of the BDD structure. A set of new formulae developed in this study for AND or OR operation between two ITE connectives of a coherent system makes it possible to delete subsets and truncate ITE connectives with a probability or size limit in the intermediate BDD structure under construction. By means of the truncation and subsuming in every step of the calculation, large fault trees for coherent systems (coherent fault trees) are efficiently solved in a short time using less memory. Furthermore, the coherent BDD algorithm from the aspect of the size of a BDD structure is much less sensitive to variable ordering than the conventional BDD algorithm

Coherent Bichromatic Force Deflection of Molecules

Science.gov (United States)

Kozyryev, Ivan; Baum, Louis; Aldridge, Leland; Yu, Phelan; Eyler, Edward E.; Doyle, John M.

2018-02-01

We demonstrate the effect of the coherent optical bichromatic force on a molecule, the polar free radical strontium monohydroxide (SrOH). A dual-frequency retroreflected laser beam addressing the X˜2Σ+↔A˜2Π1 /2 electronic transition coherently imparts momentum onto a cryogenic beam of SrOH. This directional photon exchange creates a bichromatic force that transversely deflects the molecules. By adjusting the relative phase between the forward and counterpropagating laser beams we reverse the direction of the applied force. A momentum transfer of 70 ℏk is achieved with minimal loss of molecules to dark states. Modeling of the bichromatic force is performed via direct numerical solution of the time-dependent density matrix and is compared with experimental observations. Our results open the door to further coherent manipulation of molecular motion, including the efficient optical deceleration of diatomic and polyatomic molecules with complex level structures.

Exhaustion from prolonged gambling

Directory of Open Access Journals (Sweden)

Fatimah Lateef

2013-01-01

Full Text Available Complaints of fatigue and physical exhaustion are frequently seen in the acute medical setting, especially amongst athletes, army recruits and persons involved in strenuous and exertional physical activities. Stress-induced exhaustion, on the other hand, is less often seen, but can present with very similar symptoms to physical exhaustion. Recently, three patients were seen at the Department of Emergency Medicine, presenting with exhaustion from prolonged involvement in gambling activities. The cases serve to highlight some of the physical consequences of prolonged gambling.

Scalable coherent interface

International Nuclear Information System (INIS)

Alnaes, K.; Kristiansen, E.H.; Gustavson, D.B.; James, D.V.

1990-01-01

The Scalable Coherent Interface (IEEE P1596) is establishing an interface standard for very high performance multiprocessors, supporting a cache-coherent-memory model scalable to systems with up to 64K nodes. This Scalable Coherent Interface (SCI) will supply a peak bandwidth per node of 1 GigaByte/second. The SCI standard should facilitate assembly of processor, memory, I/O and bus bridge cards from multiple vendors into massively parallel systems with throughput far above what is possible today. The SCI standard encompasses two levels of interface, a physical level and a logical level. The physical level specifies electrical, mechanical and thermal characteristics of connectors and cards that meet the standard. The logical level describes the address space, data transfer protocols, cache coherence mechanisms, synchronization primitives and error recovery. In this paper we address logical level issues such as packet formats, packet transmission, transaction handshake, flow control, and cache coherence. 11 refs., 10 figs

The design of an energy harvesting device for prolonging the working time of DC equipment

Science.gov (United States)

Wen, Yayuan; Deng, Huaxia; Zhang, Jin; Yu, Liandong

2016-01-01

Energy harvesting (EH) derives from the idea of converting the ambient energy into electric energy, which can solve the problem of DC supply for some electronic equipment. PZT is a typical piezoelectric material of inorganic, which has been developed as EH devices to transfer ambient vibration energy into electric energy. However, these PZT devices require relatively violent excitation, and easy to be fatigue fracture under the resonance condition. In this paper, PVDF, which is a kind of soft piezoelectric polymer, is adopted for developing transducer. The PVDF devices are flexible and have longer life time than PZT devices under the harmonic environment. The EH researches are mainly focused on the development of energy transfer efficiency either by the mechanical structure of transducer or the improvement of circuit. However, the practicality and stability of the EH devices are important in the practical engineering applications. In this paper, a charge amplifier is introduced in the circuit in order to guarantee the stability of the battery charging under small ambient vibration conditions. The model of the mechanical structure of PVDF and the electric performance of circuit are developed. The experimental results and simulation show that the stability of battery charging is improved and the working time of DC equipment is prolonged.

Coherent detectors

International Nuclear Information System (INIS)

Lawrence, C R; Church, S; Gaier, T; Lai, R; Ruf, C; Wollack, E

2009-01-01

Coherent systems offer significant advantages in simplicity, testability, control of systematics, and cost. Although quantum noise sets the fundamental limit to their performance at high frequencies, recent breakthroughs suggest that near-quantum-limited noise up to 150 or even 200 GHz could be realized within a few years. If the demands of component separation can be met with frequencies below 200 GHz, coherent systems will be strong competitors for a space CMB polarization mission. The rapid development of digital correlator capability now makes space interferometers with many hundreds of elements possible. Given the advantages of coherent interferometers in suppressing systematic effects, such systems deserve serious study.

Coherent detectors

Energy Technology Data Exchange (ETDEWEB)

Lawrence, C R [M/C 169-327, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Church, S [Room 324 Varian Physics Bldg, 382 Via Pueblo Mall, Stanford, CA 94305-4060 (United States); Gaier, T [M/C 168-314, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Lai, R [Northrop Grumman Corporation, Redondo Beach, CA 90278 (United States); Ruf, C [1533 Space Research Building, The University of Michigan, Ann Arbor, MI 48109-2143 (United States); Wollack, E, E-mail: charles.lawrence@jpl.nasa.go [NASA/GSFC, Code 665, Observational Cosmology Laboratory, Greenbelt, MD 20771 (United States)

2009-03-01

Coherent systems offer significant advantages in simplicity, testability, control of systematics, and cost. Although quantum noise sets the fundamental limit to their performance at high frequencies, recent breakthroughs suggest that near-quantum-limited noise up to 150 or even 200 GHz could be realized within a few years. If the demands of component separation can be met with frequencies below 200 GHz, coherent systems will be strong competitors for a space CMB polarization mission. The rapid development of digital correlator capability now makes space interferometers with many hundreds of elements possible. Given the advantages of coherent interferometers in suppressing systematic effects, such systems deserve serious study.

Temporal coherence of the acoustic field forward propagated through a continental shelf with random internal waves.

Science.gov (United States)

Gong, Zheng; Chen, Tianrun; Ratilal, Purnima; Makris, Nicholas C

2013-11-01

An analytical model derived from normal mode theory for the accumulated effects of range-dependent multiple forward scattering is applied to estimate the temporal coherence of the acoustic field forward propagated through a continental-shelf waveguide containing random three-dimensional internal waves. The modeled coherence time scale of narrow band low-frequency acoustic field fluctuations after propagating through a continental-shelf waveguide is shown to decay with a power-law of range to the -1/2 beyond roughly 1 km, decrease with increasing internal wave energy, to be consistent with measured acoustic coherence time scales. The model should provide a useful prediction of the acoustic coherence time scale as a function of internal wave energy in continental-shelf environments. The acoustic coherence time scale is an important parameter in remote sensing applications because it determines (i) the time window within which standard coherent processing such as matched filtering may be conducted, and (ii) the number of statistically independent fluctuations in a given measurement period that determines the variance reduction possible by stationary averaging.

The x-ray laser coherence experiments in neon-like yttrium

International Nuclear Information System (INIS)

Shimkaveg, G.M.; Carter, M.R.; Walling, R.S.; Ticehurst, J.M.; Koch, J.A.; Mrowka, S.; Trebes, J.E.; MacGowan, B.J.; Da Silva, L.B.; Matthews, D.L.; London, R.A.; Stewart, R.E.

1992-01-01

We present recent results from neon-like x-ray laser experiments conducted at the Nova laser's Two-Beam Facility. This begins a series of experiments aimed at the characterization and control of the degree of spatial coherece in our soft x-ray laser beams, important to planned applications areas susch as microscopy and holography. New instrumentation developed for this effort include a fully time-resolved coherence diagnostic (which records a multiple-slit diffraction pattern) and wide-angle extreme ultraviolet spectrographs and beam divergence cameras. We present new measurements of beam profiles and gain, as well as spatial coherence data such as time-resolved multi-slit diffraction patterns. This new time-resolved coherence data exhibit aperture functions which increase in size during the time of the lasing. Also, some preliminary data is given from the first ''double-foil'' experiments, involving two x-ray amplifiers spatially separated by 29 cm and shot sequentially, in an ''oscillator-amplifier'' configuration

Teleportation of a Coherent Superposition State Via a nonmaximally Entangled Coherent Xhannel

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

@@ We investigate the problemm of teleportation of a superposition coherent state with nonmaximally entangled coherent channel. Two strategies are considered to complete the task. The first one uses entanglement concentration to purify the channel to a maximally entangled one. The second one teleports the state through the nonmaximally entangled coherent channel directly. We find that the probabilities of successful teleportations for the two strategies are depend on the amplitudes of the coherent states and the mean fidelity of teleportation using the first strategy is always less than that of the second strategy.

Prolonged ventilation post cardiac surgery - tips and pitfalls of the prediction game

Directory of Open Access Journals (Sweden)

Knapik Piotr

2011-11-01

Full Text Available Abstract Background Few available models aim to identify patients at risk of prolonged ventilation after cardiac surgery. We compared prediction models developed in ICU in two adjacent periods of time, when significant changes were observed both in population characteristics and the perioperative management. Methods We performed a retrospective review of two cohorts of patients in our department in two subsequent time periods (July 2007 - December 2008, n = 2165; January 2009 - July 2010, n = 2192. The study was approved by the Institutional Ethics Committee and the individual patient consent was not required. Patients were divided with regard to ventilation time of more or less than 48 hours. Preoperative and procedure-related variables for prolonged ventilation were identified and multivariate logistic regression analysis was performed separately for each cohort. Results Most recent patients were older, with more co-morbidities, more frequently undergoing off-pump surgery. At the beginning of 2009 we also changed the technique of postoperative ventilation. Percentage of patients with prolonged ventilation decreased from 5.7% to 2.4% (p Conclusions Prediction models for postoperative ventilation should be regularly updated, particularly when major changes are noted in patients' demographics and surgical or anaesthetic technique.

A COHERENT TIMING SOLUTION FOR THE NEARBY, THERMALLY EMITTING ISOLATED NEUTRON STAR RX J0420.0-5022

International Nuclear Information System (INIS)

Kaplan, D. L.; Van Kerkwijk, M. H.

2011-01-01

We present a phase-coherent timing solution for RX J0420.0-5022, the coolest (kT ≅ 45 eV) and fastest-spinning (P = 3.45 s) of the seven so-called isolated neutron stars (INSs). Using 14 observations with the XMM-Newton spacecraft in 2010 and 2011, we were able to measure a spin-down rate ν-dot = (-2.3 ± 0.2) x 10 15 Hz s -1 (P-dot =(2.8±0.3)x10 -14 s s -1 ), from which we infer a dipolar magnetic field of 1.0 x 10 13 G. With reasonable confidence we were able to extend the timing solution back to archival XMM-Newton from 2002 and 2003, giving the same solution but with considerably more precision. This gives RX J0420.0-5022 the lowest dipole magnetic field of the INSs. Our spectroscopy does not confirm the broad absorption feature at 0.3 keV hinted at in earlier observations, although difficulties in background subtraction near that energy make conclusions difficult. With this, all six of the INSs that have confirmed periodicities now have constrained spin-downs from coherent solutions. The evidence that the INSs are qualitatively different from rotation-powered pulsars now appears robust, with the likely conclusion that their characteristic ages are systematically older than their true ages, because their fields have decayed. The field decay probably also causes them to be systematically hotter than pulsars of the same (true) age.

q-deformed charged fermion coherent states and SU(3) charged, Hyper-charged fermion coherent states

International Nuclear Information System (INIS)

Hao Sanru; Li Guanghua; Long Junyan

1994-01-01

By virtue of the algebra of the q-deformed fermion oscillators, the q-deformed charged fermion coherent states and SU(3) charged, hyper-charged fermion coherent states are discussed. The explicit forms of the two kinds of coherent states mentioned above are obtained by making use of the completeness of base vectors in the q-fermion Fock space. By comparing the q-deformed results with the ordinary results, it is found that the q-deformed charged fermion coherent states and SU(3) charged, hyper-charged fermion coherent states are automatically reduced to the ordinary charged fermion coherent states and SU(3) charged hyper-charged fermion coherent states if the deformed parameter q→1

Safety information on QT-interval prolongation

DEFF Research Database (Denmark)

Warnier, Miriam J; Holtkamp, Frank A; Rutten, Frans H

2014-01-01

Prolongation of the QT interval can predispose to fatal ventricular arrhythmias. Differences in QT-labeling language can result in miscommunication and suboptimal risk mitigation. We systematically compared the phraseology used to communicate on QT-prolonging properties of 144 drugs newly approve...

Optimism in prolonged grief and depression following loss: A three-wave longitudinal study.

Science.gov (United States)

Boelen, Paul A

2015-06-30

There is considerable evidence that optimism, the predisposition to have generalized favorable expectancies for the future, is associated with numerous desirable outcomes. Few studies have examined the association of optimism with emotional distress following the death of a loved one. Doing so is important, because optimism may be an important target for interventions for post-loss psychopathology. In the current study, we examined the degree to which optimism, assessed in the first year post-loss (Time 1, T1), was associated with symptom levels of prolonged grief and depression six months (Time 2, T2) and fifteen months (Time 3, T3) later, controlling for baseline symptoms and also taking into account positive automatic cognitions at T1. Findings showed that higher optimism at T1 was associated with lower concurrent prolonged grief and depression severity. Higher optimism at T1 was also inversely related with depression symptom severity at T2 and T3, but not prolonged grief severity at T2 and T3. Implications of these findings are discussed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

In vivo assessment of catheter positioning accuracy and prolonged irradiation time on liver tolerance dose after single-fraction 192Ir high-dose-rate brachytherapy

Directory of Open Access Journals (Sweden)

Kropf Siegfried

2011-09-01

Full Text Available Abstract Background To assess brachytherapy catheter positioning accuracy and to evaluate the effects of prolonged irradiation time on the tolerance dose of normal liver parenchyma following single-fraction irradiation with 192 Ir. Materials and methods Fifty patients with 76 malignant liver tumors treated by computed tomography (CT-guided high-dose-rate brachytherapy (HDR-BT were included in the study. The prescribed radiation dose was delivered by 1 - 11 catheters with exposure times in the range of 844 - 4432 seconds. Magnetic resonance imaging (MRI datasets for assessing irradiation effects on normal liver tissue, edema, and hepatocyte dysfunction, obtained 6 and 12 weeks after HDR-BT, were merged with 3D dosimetry data. The isodose of the treatment plan covering the same volume as the irradiation effect was taken as a surrogate for the liver tissue tolerance dose. Catheter positioning accuracy was assessed by calculating the shift between the 3D center coordinates of the irradiation effect volume and the tolerance dose volume for 38 irradiation effects in 30 patients induced by catheters implanted in nearly parallel arrangement. Effects of prolonged irradiation were assessed in areas where the irradiation effect volume and tolerance dose volume did not overlap (mismatch areas by using a catheter contribution index. This index was calculated for 48 irradiation effects induced by at least two catheters in 44 patients. Results Positioning accuracy of the brachytherapy catheters was 5-6 mm. The orthogonal and axial shifts between the center coordinates of the irradiation effect volume and the tolerance dose volume in relation to the direction vector of catheter implantation were highly correlated and in first approximation identically in the T1-w and T2-w MRI sequences (p = 0.003 and p p = 0.001 and p = 0.004, respectively. There was a significant shift of the irradiation effect towards the catheter entry site compared with the planned dose

Perfect-crystal x-ray optics to treat x-ray coherence

International Nuclear Information System (INIS)

Yamazaki, Hiroshi; Ishikawa, Tetsuya

2007-01-01

X-ray diffraction of perfect crystals, which serve as x-ray monochromator and collimator, modifies coherence properties of x-ray beams. From the time-dependent Takagi-Taupin equations that x-ray wavefields obey in crystals, the reflected wavefield is formulated as an integral transform of a general incident wavefield with temporal and spatial inhomogeneity. A reformulation of rocking-curve profiles from the field solution of the Takagi-Taupin equations allows experimental evaluation of the mutual coherence function of x-ray beam. The rigorous relationship of the coherence functions between before and after reflection clarifies how the coherence is transferred by a crystal. These results will be beneficial to developers of beamline optics for the next generation synchrotron sources. (author)

Differences between time domain and Fourier domain optical coherence tomography in imaging tissues.

Science.gov (United States)

Gao, W; Wu, X

2017-11-01

It has been numerously demonstrated that both time domain and Fourier domain optical coherence tomography (OCT) can generate high-resolution depth-resolved images of living tissues and cells. In this work, we compare the common points and differences between two methods when the continuous and random properties of live tissue are taken into account. It is found that when relationships that exist between the scattered light and tissue structures are taken into account, spectral interference measurements in Fourier domain OCT (FDOCT) is more advantageous than interference fringe envelope measurements in time domain OCT (TDOCT) in the cases where continuous property of tissue is taken into account. It is also demonstrated that when random property of tissue is taken into account FDOCT measures the Fourier transform of the spatial correlation function of the refractive index and speckle phenomena will limit the effective limiting imaging resolution in both TDOCT and FDOCT. Finally, the effective limiting resolution of both TDOCT and FDOCT are given which can be used to estimate the effective limiting resolution in various practical applications. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Genetic influence on prolonged gestation

DEFF Research Database (Denmark)

Laursen, Maja; Bille, Camilla; Olesen, Annette Wind

2004-01-01

OBJECTIVE: The purpose of this study was to test a possible genetic component to prolonged gestation. STUDY DESIGN: The gestational duration of single, first pregnancies by both female and male twins was obtained by linking the Danish Twin Registry, The Danish Civil Registration System, and the D...... factors. CONCLUSION: Maternal genes influence prolonged gestation. However, a substantial paternal genetic influence through the fetus was not found....

Stochastic modeling of neurobiological time series: Power, coherence, Granger causality, and separation of evoked responses from ongoing activity

Science.gov (United States)

Chen, Yonghong; Bressler, Steven L.; Knuth, Kevin H.; Truccolo, Wilson A.; Ding, Mingzhou

2006-06-01

In this article we consider the stochastic modeling of neurobiological time series from cognitive experiments. Our starting point is the variable-signal-plus-ongoing-activity model. From this model a differentially variable component analysis strategy is developed from a Bayesian perspective to estimate event-related signals on a single trial basis. After subtracting out the event-related signal from recorded single trial time series, the residual ongoing activity is treated as a piecewise stationary stochastic process and analyzed by an adaptive multivariate autoregressive modeling strategy which yields power, coherence, and Granger causality spectra. Results from applying these methods to local field potential recordings from monkeys performing cognitive tasks are presented.

Topological Properties of Spatial Coherence Function

International Nuclear Information System (INIS)

Ji-Rong, Ren; Tao, Zhu; Yi-Shi, Duan

2008-01-01

The topological properties of the spatial coherence function are investigated rigorously. The phase singular structures (coherence vortices) of coherence function can be naturally deduced from the topological current, which is an abstract mathematical object studied previously. We find that coherence vortices are characterized by the Hopf index and Brouwer degree in topology. The coherence flux quantization and the linking of the closed coherence vortices are also studied from the topological properties of the spatial coherence function

Real-time three-dimensional imaging of epidermal splitting and removal by high-definition optical coherence tomography.

Science.gov (United States)

Boone, Marc; Draye, Jean Pierre; Verween, Gunther; Pirnay, Jean-Paul; Verbeken, Gilbert; De Vos, Daniel; Rose, Thomas; Jennes, Serge; Jemec, Gregor B E; Del Marmol, Véronique

2014-10-01

While real-time 3-D evaluation of human skin constructs is needed, only 2-D non-invasive imaging techniques are available. The aim of this paper is to evaluate the potential of high-definition optical coherence tomography (HD-OCT) for real-time 3-D assessment of the epidermal splitting and decellularization. Human skin samples were incubated with four different agents: Dispase II, NaCl 1 M, sodium dodecyl sulphate (SDS) and Triton X-100. Epidermal splitting, dermo-epidermal junction, acellularity and 3-D architecture of dermal matrices were evaluated by High-definition optical coherence tomography before and after incubation. Real-time 3-D HD-OCT assessment was compared with 2-D en face assessment by reflectance confocal microscopy (RCM). (Immuno) histopathology was used as control. HD-OCT imaging allowed real-time 3-D visualization of the impact of selected agents on epidermal splitting, dermo-epidermal junction, dermal architecture, vascular spaces and cellularity. RCM has a better resolution (1 μm) than HD-OCT (3 μm), permitting differentiation of different collagen fibres, but HD-OCT imaging has deeper penetration (570 μm) than RCM imaging (200 μm). Dispase II and NaCl treatments were found to be equally efficient in the removal of the epidermis from human split-thickness skin allografts. However, a different epidermal splitting level at the dermo-epidermal junction could be observed and confirmed by immunolabelling of collagen type IV and type VII. Epidermal splitting occurred at the level of the lamina densa with dispase II and above the lamina densa (in the lamina lucida) with NaCl. The 3-D architecture of dermal papillae and dermis was more affected by Dispase II on HD-OCT which corresponded with histopathologic (orcein staining) fragmentation of elastic fibres. With SDS treatment, the epidermal removal was incomplete as remnants of the epidermal basal cell layer remained attached to the basement membrane on the dermis. With Triton X-100 treatment

Coherent quantum dynamics of excitons in monolayer transition metal dichalcogenides

KAUST Repository

Moody, Galan

2016-03-14

Transition metal dichalcogenides (TMDs) have garnered considerable interest in recent years owing to their layer thickness-dependent optoelectronic properties. In monolayer TMDs, the large carrier effective masses, strong quantum confinement, and reduced dielectric screening lead to pronounced exciton resonances with remarkably large binding energies and coupled spin and valley degrees of freedom (valley excitons). Coherent control of valley excitons for atomically thin optoelectronics and valleytronics requires understanding and quantifying sources of exciton decoherence. In this work, we reveal how exciton-exciton and exciton-phonon scattering influence the coherent quantum dynamics of valley excitons in monolayer TMDs, specifically tungsten diselenide (WSe2), using two-dimensional coherent spectroscopy. Excitation-density and temperature dependent measurements of the homogeneous linewidth (inversely proportional to the optical coherence time) reveal that exciton-exciton and exciton-phonon interactions are significantly stronger compared to quasi-2D quantum wells and 3D bulk materials. The residual homogeneous linewidth extrapolated to zero excitation density and temperature is ~1:6 meV (equivalent to a coherence time of 0.4 ps), which is limited only by the population recombination lifetime in this sample. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Coherent quantum dynamics of excitons in monolayer transition metal dichalcogenides

KAUST Repository

Moody, Galan; Hao, Kai; Dass, Chandriker Kavir; Singh, Akshay; Xu, Lixiang; Tran, Kha; Chen, Chang-Hsiao; Li, Ming-yang; Li, Lain-Jong; Clark, Genevieve; Bergh ä user, Gunnar; Malic, Ermin; Knorr, Andreas; Xu, Xiaodong; Li, Xiaoqin

2016-01-01

Transition metal dichalcogenides (TMDs) have garnered considerable interest in recent years owing to their layer thickness-dependent optoelectronic properties. In monolayer TMDs, the large carrier effective masses, strong quantum confinement, and reduced dielectric screening lead to pronounced exciton resonances with remarkably large binding energies and coupled spin and valley degrees of freedom (valley excitons). Coherent control of valley excitons for atomically thin optoelectronics and valleytronics requires understanding and quantifying sources of exciton decoherence. In this work, we reveal how exciton-exciton and exciton-phonon scattering influence the coherent quantum dynamics of valley excitons in monolayer TMDs, specifically tungsten diselenide (WSe2), using two-dimensional coherent spectroscopy. Excitation-density and temperature dependent measurements of the homogeneous linewidth (inversely proportional to the optical coherence time) reveal that exciton-exciton and exciton-phonon interactions are significantly stronger compared to quasi-2D quantum wells and 3D bulk materials. The residual homogeneous linewidth extrapolated to zero excitation density and temperature is ~1:6 meV (equivalent to a coherence time of 0.4 ps), which is limited only by the population recombination lifetime in this sample. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Coherently combining data between detectors for all-sky semi-coherent continuous gravitational wave searches

International Nuclear Information System (INIS)

Goetz, E; Riles, K

2016-01-01

We present a method for coherently combining short data segments from gravitational-wave detectors to improve the sensitivity of semi-coherent searches for continuous gravitational waves. All-sky searches for continuous gravitational waves from unknown sources are computationally limited. The semi-coherent approach reduces the computational cost by dividing the entire observation timespan into short segments to be analyzed coherently, then combined together incoherently. Semi-coherent analyses that attempt to improve sensitivity by coherently combining data from multiple detectors face a computational challenge in accounting for uncertainties in signal parameters. In this article, we lay out a technique to meet this challenge using summed Fourier transform coefficients. Applying this technique to one all-sky search algorithm called TwoSpect, we confirm that the sensitivity of all-sky, semi-coherent searches can be improved by coherently combining the short data segments, e.g., by up to 42% over a single detector for an all-sky search. For misaligned detectors, however, this improvement requires careful attention when marginalizing over unknown polarization parameters. In addition, care must be taken in correcting for differential detector velocity due to the Earth’s rotation for high signal frequencies and widely separated detectors. (paper)

Coherent control of interfering wave packets in dissociating HD+ molecules: the role of phase and delay time

International Nuclear Information System (INIS)

Qin, Chaochao; Zhang, Lili; Zhang, Xianzhou; Liu, Yufang; Qiu, Xuejun

2016-01-01

The coherent control of interference between dissociating wave packets of the HD + molecules generated by a pair of time-delayed and phase-locked femtosecond laser pulses is theoretically studied by using the time-dependent quantum wave packet method. The density function in both coordinate and momentum representation are presented and discussed. It is demonstrated that the interference pattern is observed in both coordinate and momentum density functions. The interference undergoes a π-phase shift when the delay time between the two phase-locked femtosecond laser pulses is changed by half an optical period. In particular, the number of interference fringes, the fringe spacing in the R-dependent density distribution |ψ(R)| 2 , and the modulation period of the energy-dependent distribution of the fragments P(E) can be tuned by two phase-locked femtosecond pulses. (paper)

Coherent defects in superconducting circuits

International Nuclear Information System (INIS)

Mueller, Clemens

2011-01-01

The interaction of superconducting circuits with additional quantum systems is a topic that has found extensive study in the recent past. In the limit where the added system are incoherent, this is the standard field of decoherence and the system dynamics can be described by a simple master equation. In the other limit however, when the additional parts are coherent, the resulting time-evolution can become more complicated. In this thesis we have investigated the interaction of superconducting circuits with coherent and incoherent two-level defects. We have shown theoretical calculations characterizing this interaction for all relevant parameter regimes. In the weak coupling limit, the interaction can be described in an effective bath picture, where the TLS act as parts of a large, decohering environment. For strong coupling, however, the coherent dynamics of the full coupled system has to be considered. We show the calculations of the coupled time-evolution and again characterize the interaction by an effective decoherence rate. We also used experimental data to characterize the microscopic origin of the defects and the details of their interaction with the circuits. The results obtained by analyzing spectroscopic data allow us to place strong constraint on several microscopic models for the observed TLS. However, these calculations are not yet fully conclusive as to the physical nature of the TLS. We propose additional experiments to fully characterize the interaction part of the Hamiltonian, thus providing the answer to the question of the physical origin of the coupling. Additionally we have developed a method to directly drive individual defect states via virtual excitation of the qubit. This method allows one to directly probe the properties of single TLS and possibly make use of their superior coherence times for quantum information purposes. The last part of this thesis provided a way for a possible implementation of geometric quantum computation in

Time-variant partial directed coherence in analysis of the cardiovascular system. A methodological study

International Nuclear Information System (INIS)

Milde, T; Schwab, K; Walther, M; Eiselt, M; Witte, H; Schelenz, C; Voss, A

2011-01-01

Time-variant partial directed coherence (tvPDC) is used for the first time in a multivariate analysis of heart rate variability (HRV), respiratory movements (RMs) and (systolic) arterial blood pressure. It is shown that respiration-related HRV components which also occur at other frequencies besides the RM frequency (= respiratory sinus arrhythmia, RSA) can be identified. These additional components are known to be an effect of the 'half-the-mean-heart-rate-dilemma' ('cardiac aliasing' CA). These CA components may contaminate the entire frequency range of HRV and can lead to misinterpretation of the RSA analysis. TvPDC analysis of simulated and clinical data (full-term neonates and sedated patients) reveals these contamination effects and, in addition, the respiration-related CA components can be separated from the RSA component and the Traube–Hering–Mayer wave. It can be concluded that tvPDC can be beneficially applied to avoid misinterpretations in HRV analyses as well as to quantify partial correlative interaction properties between RM and RSA

Time line cell tracking for the approximation of lagrangian coherent structures with subgrid accuracy

KAUST Repository

Kuhn, Alexander

2013-12-05

Lagrangian coherent structures (LCSs) have become a widespread and powerful method to describe dynamic motion patterns in time-dependent flow fields. The standard way to extract LCS is to compute height ridges in the finite-time Lyapunov exponent field. In this work, we present an alternative method to approximate Lagrangian features for 2D unsteady flow fields that achieve subgrid accuracy without additional particle sampling. We obtain this by a geometric reconstruction of the flow map using additional material constraints for the available samples. In comparison to the standard method, this allows for a more accurate global approximation of LCS on sparse grids and for long integration intervals. The proposed algorithm works directly on a set of given particle trajectories and without additional flow map derivatives. We demonstrate its application for a set of computational fluid dynamic examples, as well as trajectories acquired by Lagrangian methods, and discuss its benefits and limitations. © 2013 The Authors Computer Graphics Forum © 2013 The Eurographics Association and John Wiley & Sons Ltd.

Real-time speckle variance swept-source optical coherence tomography using a graphics processing unit.

Science.gov (United States)

Lee, Kenneth K C; Mariampillai, Adrian; Yu, Joe X Z; Cadotte, David W; Wilson, Brian C; Standish, Beau A; Yang, Victor X D

2012-07-01

Advances in swept source laser technology continues to increase the imaging speed of swept-source optical coherence tomography (SS-OCT) systems. These fast imaging speeds are ideal for microvascular detection schemes, such as speckle variance (SV), where interframe motion can cause severe imaging artifacts and loss of vascular contrast. However, full utilization of the laser scan speed has been hindered by the computationally intensive signal processing required by SS-OCT and SV calculations. Using a commercial graphics processing unit that has been optimized for parallel data processing, we report a complete high-speed SS-OCT platform capable of real-time data acquisition, processing, display, and saving at 108,000 lines per second. Subpixel image registration of structural images was performed in real-time prior to SV calculations in order to reduce decorrelation from stationary structures induced by the bulk tissue motion. The viability of the system was successfully demonstrated in a high bulk tissue motion scenario of human fingernail root imaging where SV images (512 × 512 pixels, n = 4) were displayed at 54 frames per second.

Spectral coherence in windturbine wakes

Energy Technology Data Exchange (ETDEWEB)

Hojstrup, J. [Riso National Lab., Roskilde (Denmark)

1996-12-31

This paper describes an experiment at a Danish wind farm to investigate the lateral and vertical coherences in the nonequilibrium turbulence of a wind turbine wake. Two meteorological masts were instrumented for measuring profiles of mean speed, turbulence, and temperature. Results are provided graphically for turbulence intensities, velocity spectra, lateral coherence, and vertical coherence. The turbulence was somewhat influenced by the wake, or possibly from aggregated wakes further upstream, even at 14.5 diameters. Lateral coherence (separation 5m) seemed to be unaffected by the wake at 7.5 diameters, but the flow was less coherent in the near wake. The wake appeared to have little influence on vertical coherence (separation 13m). Simple, conventional models for coherence appeared to be adequate descriptions for wake turbulence except for the near wake situation. 3 refs., 7 figs., 1 tab.

Risk factors for QTc interval prolongation

NARCIS (Netherlands)

Heemskerk, Charlotte P.M.; Pereboom, Marieke; van Stralen, Karlijn; Berger, Florine A.; van den Bemt, Patricia M.L.A.; Kuijper, Aaf F.M.; van der Hoeven, Ruud T M; Mantel-Teeuwisse, Aukje K.; Becker, Matthijs L

2018-01-01

Purpose: Prolongation of the QTc interval may result in Torsade de Pointes, a ventricular arrhythmia. Numerous risk factors for QTc interval prolongation have been described, including the use of certain drugs. In clinical practice, there is much debate about the management of the risks involved. In

Sidestep and crossover lower limb kinematics during a prolonged sport-like agility test.

Science.gov (United States)

Potter, Danielle; Reidinger, Kellie; Szymialowicz, Rebecca; Martin, Thomas; Dione, Donald; Feinn, Richard; Wallace, David; Garbalosa, Juan C

2014-10-01

Non-contact anterior cruciate ligament (ACL) injuries in athletes occur more often towards the end of athletic competitions. However, the exact mechanisms of how prolonged activity increases the risk for ACL injuries are not clear. To determine the effect of prolonged activity on the hip and knee kinematics observed during self-selected cutting maneuvers performed in a timed agility test. Nineteen female Division I collegiate soccer players completed a self-selected cutting agility test until they were unable to meet a set performance time (one standard deviation of the average baseline trial). Using the 3D dimensional coordinate data the cut type was identified by the principle investigators. The 3D hip and knee angles at 32ms post heel strike were analyzed using a two-factor, linear mixed model to assess the effect of prolonged activity and cut type on the recorded mean hip and knee angles. Athletes performed either sidestep or crossover cuts. An effect of cut type and prolonged activity was seen at the hip and knee. During the prolonged activity trials, the knee was relatively more adducted and both the hip and knee were less flexed than during the baseline trials regardless of cut type. Regardless of activity status, during sidestep cuts, the hip was more internally rotated and abducted, and less flexed than during crossover cuts while the knee was more abducted and less flexed during the sidestep than crossover cuts. During a sport-like agility test, prolonged activity appears to predispose the athlete to position their knee in a more extended and abducted posture and their hip in a more extended posture. This position has been suggested to place stress on the ACL and potentially increase the risk for injury. Clinicians may want to consider the effects of prolonged activity on biomechanical risk factors for sustaining ACL injuries in the design of intervention strategies to prevent ACL injuries. Level 4.

Non-equilibrium coherence dynamics in one-dimensional Bose gases.

Science.gov (United States)

Hofferberth, S; Lesanovsky, I; Fischer, B; Schumm, T; Schmiedmayer, J

2007-09-20

Low-dimensional systems provide beautiful examples of many-body quantum physics. For one-dimensional (1D) systems, the Luttinger liquid approach provides insight into universal properties. Much is known of the equilibrium state, both in the weakly and strongly interacting regimes. However, it remains a challenge to probe the dynamics by which this equilibrium state is reached. Here we present a direct experimental study of the coherence dynamics in both isolated and coupled degenerate 1D Bose gases. Dynamic splitting is used to create two 1D systems in a phase coherent state. The time evolution of the coherence is revealed through local phase shifts of the subsequently observed interference patterns. Completely isolated 1D Bose gases are observed to exhibit universal sub-exponential coherence decay, in excellent agreement with recent predictions. For two coupled 1D Bose gases, the coherence factor is observed to approach a non-zero equilibrium value, as predicted by a Bogoliubov approach. This coupled-system decay to finite coherence is the matter wave equivalent of phase-locking two lasers by injection. The non-equilibrium dynamics of superfluids has an important role in a wide range of physical systems, such as superconductors, quantum Hall systems, superfluid helium and spin systems. Our experiments studying coherence dynamics show that 1D Bose gases are ideally suited for investigating this class of phenomena.

Doppler optical coherence microscopy and tomography applied to inner ear mechanics

Energy Technology Data Exchange (ETDEWEB)

Page, Scott; Freeman, Dennis M. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Ghaffari, Roozbeh [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States)

2015-12-31

While it is clear that cochlear traveling waves underlie the extraordinary sensitivity, frequency selectivity, and dynamic range of mammalian hearing, the underlying micromechanical mechanisms remain unresolved. Recent advances in low coherence measurement techniques show promise over traditional laser Doppler vibrometry and video microscopy, which are limited by low reflectivities of cochlear structures and restricted optical access. Doppler optical coherence tomography (DOCT) and Doppler optical coherence microscopy (DOCM) both utilize a broadband source to limit constructive interference of scattered light to a small axial depth called a coherence gate. The coherence gate can be swept axially to image and measure sub-nanometer motions of cochlear structures throughout the cochlear partition. The coherence gate of DOCT is generally narrower than the confocal gate of the focusing optics, enabling increased axial resolution (typically 15 μm) within optical sections of the cochlear partition. DOCM, frequently implemented in the time domain, centers the coherence gate on the focal plane, achieving enhanced lateral and axial resolution when the confocal gate is narrower than the coherence gate. We compare these two complementary systems and demonstrate their utility in studying cellular and micromechanical mechanisms involved in mammalian hearing.

COHERENTLY DEDISPERSED GATED IMAGING OF MILLISECOND PULSARS

International Nuclear Information System (INIS)

Roy, Jayanta; Bhattacharyya, Bhaswati

2013-01-01

Motivated by the need for rapid localization of newly discovered faint millisecond pulsars (MSPs), we have developed a coherently dedispersed gating correlator. This gating correlator accounts for the orbital motions of MSPs in binaries while folding the visibilities with a best-fit topocentric rotational model derived from a periodicity search in a simultaneously generated beamformer output. Unique applications of the gating correlator for sensitive interferometric studies of MSPs are illustrated using the Giant Metrewave Radio Telescope (GMRT) interferometric array. We could unambiguously localize five newly discovered Fermi MSPs in the on-off gated image plane with an accuracy of ±1''. Immediate knowledge of such a precise position enables the use of sensitive coherent beams of array telescopes for follow-up timing observations which substantially reduces the use of telescope time (∼20× for the GMRT). In addition, a precise a priori astrometric position reduces the effect of large covariances in the timing fit (with discovery position, pulsar period derivative, and an unknown binary model), which in-turn accelerates the convergence to the initial timing model. For example, while fitting with the precise a priori position (±1''), the timing model converges in about 100 days, accounting for the effect of covariance between the position and pulsar period derivative. Moreover, such accurate positions allow for rapid identification of pulsar counterparts at other wave bands. We also report a new methodology of in-beam phase calibration using the on-off gated image of the target pulsar, which provides optimal sensitivity of the coherent array removing possible temporal and spacial decoherences.

COHERENTLY DEDISPERSED GATED IMAGING OF MILLISECOND PULSARS

Energy Technology Data Exchange (ETDEWEB)

Roy, Jayanta; Bhattacharyya, Bhaswati [National Centre for Radio Astrophysics, Pune 411007 (India)

2013-03-10

Motivated by the need for rapid localization of newly discovered faint millisecond pulsars (MSPs), we have developed a coherently dedispersed gating correlator. This gating correlator accounts for the orbital motions of MSPs in binaries while folding the visibilities with a best-fit topocentric rotational model derived from a periodicity search in a simultaneously generated beamformer output. Unique applications of the gating correlator for sensitive interferometric studies of MSPs are illustrated using the Giant Metrewave Radio Telescope (GMRT) interferometric array. We could unambiguously localize five newly discovered Fermi MSPs in the on-off gated image plane with an accuracy of {+-}1''. Immediate knowledge of such a precise position enables the use of sensitive coherent beams of array telescopes for follow-up timing observations which substantially reduces the use of telescope time ({approx}20 Multiplication-Sign for the GMRT). In addition, a precise a priori astrometric position reduces the effect of large covariances in the timing fit (with discovery position, pulsar period derivative, and an unknown binary model), which in-turn accelerates the convergence to the initial timing model. For example, while fitting with the precise a priori position ({+-}1''), the timing model converges in about 100 days, accounting for the effect of covariance between the position and pulsar period derivative. Moreover, such accurate positions allow for rapid identification of pulsar counterparts at other wave bands. We also report a new methodology of in-beam phase calibration using the on-off gated image of the target pulsar, which provides optimal sensitivity of the coherent array removing possible temporal and spacial decoherences.

Testing aspects of advanced coherent electron cooling technique

Energy Technology Data Exchange (ETDEWEB)

Litvinenko, V.; Jing, Y.; Pinayev, I.; Wang, G.; Samulyak, R.; Ratner, D.

2015-05-03

An advanced version of the Coherent-electron Cooling (CeC) based on the micro-bunching instability was proposed. This approach promises significant increase in the bandwidth of the CeC system and, therefore, significant shortening of cooling time in high-energy hadron colliders. In this paper we present our plans of simulating and testing the key aspects of this proposed technique using the set-up of the coherent-electron-cooling proof-of-principle experiment at BNL.

Effect of angular-momentum dissipation and fluctuation on energy coherence lengths and time evolution in the dissipative collision 28Si+48Ti

International Nuclear Information System (INIS)

Kun, S.Yu.; WITS Univ., Johannesburg; Noerenberg, W.; TH Darmstadt; Papa, M.

1992-09-01

We analyze the energy autocorrelation functions and the energy coherence lengths in the strongly dissipative collision 28 Si(E lab = 130 MeV) + 4 8Ti for Z=11 and 12 reaction fragments. It is found that in order to obtain a good fit of both the energy averaged angular distributions and the angular dependence of the energy coherence lengths one has to take into account (i) the dissipation and fluctuation of the relative angular momentum of the dinucleus and (ii) the contribution from direct (fast) reactions in addition to the statistical (relatively slow) interaction processes. The established angular dependence is a direct consequence of the angular-momentum dissipation-fluctuation effects on the time-space evolution of the intermediate dinucleus. (orig.)

Intermedin A, a New Labdane Diterpene Isolated from Alpinia intermedia, Prolonged the Survival Time of P-388D1 Tumor-Bearing CDF1 Mice.

Science.gov (United States)

Chen, Lih-Geeng; Su, Pei-Jung; Tsai, Po-Wei; Yang, Ling-Ling; Wang, Ching-Chiung

2017-01-01

Eight ethanolic extracts of indigenous Taiwanese plants of the genus Alpinia were tested for tumor cytotoxicity against AGS, Hep G2, HeLa, KB, and HL-60 cells. Among the 50 % and 95 % EtOH extracts of eight Alpinia species, the cytotoxic effects of Alpinia intermedia leaves were the strongest. When the leaf extract of A. intermedia was partitioned using n -hexane and aqueous solvents, the n -hexane layer showed a greater cytotoxic effect and could prolong the survival time of P-388D 1 tumor-bearing CDF1 mice. Two new labdane diterpene derivatives, intermedin A ( 1 ) and intermedin B ( 2 ), and coronarin E ( 3 ) were isolated from the n -hexane layer of A. intermedia . Intermedin A induced apoptosis in HL-60 cells at 30 µg/mL and significantly prolonged the survival time of P-388D 1 tumor-bearing CDF 1 mice by 48.7 % at 20 mg/kg of body weight. We suggest that intermedin A is a major compound of A. intermedia and has a cytotoxic effect on HL-60 and P-388D 1 cells. Georg Thieme Verlag KG Stuttgart · New York.

Coherent states of non-relativistic electron in the magnetic-solenoid field

International Nuclear Information System (INIS)

Bagrov, V G; Gavrilov, S P; Filho, D P Meira; Gitman, D M

2010-01-01

In the present work we construct coherent states in the magnetic-solenoid field, which is a superposition of the Aharonov-Bohm field and a collinear uniform magnetic field. In the problem under consideration there are two kinds of coherent states, those which correspond to classical trajectories which embrace the solenoid and those which do not. The constructed coherent states reproduce exactly classical trajectories, maintain their form under the time evolution and form a complete set of functions, which can be useful in semiclassical calculations. In the absence of the solenoid field these states are reduced to the well known in the case of uniform magnetic field Malkin-Man'ko coherent states.

The influence of a consumer-wearable activity tracker on sedentary time and prolonged sedentary bouts: secondary analysis of a randomized controlled trial.

Science.gov (United States)

Sloan, Robert A; Kim, Youngdeok; Sahasranaman, Aarti; Müller-Riemenschneider, Falk; Biddle, Stuart J H; Finkelstein, Eric A

2018-03-22

A recent meta-analysis surmised pedometers were a useful panacea to independently reduce sedentary time (ST). To further test and expand on this deduction, we analyzed the ability of a consumer-wearable activity tracker to reduce ST and prolonged sedentary bouts (PSB). We originally conducted a 12-month randomized control trial where 800 employees from 13 organizations were assigned to control, activity tracker, or one of two activity tracker plus incentive groups designed to increase step count. The primary outcome was accelerometer measured moderate-to-vigorous physical activity. We conducted a secondary analysis on accelerometer measured daily ST and PSB bouts. A general linear mixed model was used to examine changes in ST and prolonged sedentary bouts, followed by between-group pairwise comparisons. Regression analyses were conducted to examine the association of changes in step counts with ST and PSB. The changes in ST and PSB were not statistically significant and not different between the groups (P consumer-wearable activity trackers as a means to reduce sedentary behavior. Trial registration NCT01855776 Registered: August 8, 2012.

Diet-consumer nitrogen isotope fractionation for prolonged fasting arthropods.

Science.gov (United States)

Mizota, Chitoshi; Yamanaka, Toshiro

2011-12-01

Nitrogen acquisition for cellular metabolism during diapause is a primary concern for herbivorous arthropods. Analyses of naturally occurring stable isotopes of nitrogen help elucidate the mechanism. Relevant articles have cited (58 times up to mid-June 2011) anomalously elevated δ(15)N (per mil deviation of (15)N/(14)N, relative to atmospheric nitrogen=0 ‰) values (diet-consumer nitrogen isotope fractionation; up to 12 ‰) for a prolonged fasting raspberry beetle (Byturus tomentosus Degeer (Coleoptera: Byturidae)), which feeds on red raspberries (Rubus idaeus: δ(15)N= ~ +2 ‰). Biologists have hypothesised that extensive recycling of amino acid nitrogen is responsible for the prolonged fasting. Since this hypothesis was proposed in 1995, scientists have integrated biochemical and molecular knowledge to support the mechanism of prolonged diapausing of animals. To test the validity of the recycling hypothesis, we analysed tissue nitrogen isotope ratios for four Japanese arthropods: the shield bug Parastrachia japonensis Scott (Hemiptera: Cydnidae), the burrower bug Canthophorus niveimarginatus Scott (Hemiptera: Cydnidae), leaf beetle Gastrophysa atrocyanea Motschulsky (Coleoptera: Chrysomelidae) and the Japanese oak silkworm Antheraea yamamai (Lepidoptera: Saturniidae), all of which fast for more than 6 months as part of their life-history strategy. Resulting diet-consumer nitrogen isotope discrimination during fasting ranged from 0 to 7‰, as in many commonly known terrestrial arthropods. We conclude that prolonged fasting of arthropods does not always result in anomalous diet-consumer nitrogen isotope fractionation, since the recycling process is closed or nearly closed with respect to nitrogen isotopes.

Intensity Ratio, Coherence and Phase of EEG during Sensory Focused Attention.

Science.gov (United States)

1981-09-01

intensity increases as reaction time increases. There have been fewer studies of the relation of EEG coherence to cognitive vari- ables. Busk and...RUGG, X.D.uAsymmtry in EEGalpha coherence and Power: Effects oftask and sex. Electroenceph. dlin. Neurophysiol. 45, 393-401, 1978. BUSK , J. and

Spiking Regularity and Coherence in Complex Hodgkin–Huxley Neuron Networks

International Nuclear Information System (INIS)

Zhi-Qiang, Sun; Ping, Xie; Wei, Li; Peng-Ye, Wang

2010-01-01

We study the effects of the strength of coupling between neurons on the spiking regularity and coherence in a complex network with randomly connected Hodgkin–Huxley neurons driven by colored noise. It is found that for the given topology realization and colored noise correlation time, there exists an optimal strength of coupling, at which the spiking regularity of the network reaches the best level. Moreover, when the temporal regularity reaches the best level, the spatial coherence of the system has already increased to a relatively high level. In addition, for the given number of neurons and noise correlation time, the values of average regularity and spatial coherence at the optimal strength of coupling are nearly independent of the topology realization. Furthermore, there exists an optimal value of colored noise correlation time at which the spiking regularity can reach its best level. These results may be helpful for understanding of the real neuron world. (cross-disciplinary physics and related areas of science and technology)

Prolongation of islet allograft survival

International Nuclear Information System (INIS)

Lacy, P.E.; Davie, J.M.; Finke, E.H.; Scharp, D.W.

1979-01-01

Pretreatment of donor rats with irradiation and silica followed by in vitro culture of the islets for 1 to 2 days prolonged survival of allografts across a minor histocompatibility barrier if hand-picked, clean islets were used for transplantation. Pretreatment of donor rats with irradiation and silica in conjunction with a single injection of antilymphocyte serum (ALS) into the recipient produced a prolongation of survival of hand-picked islets transplanted across a major histocompatibility barrier

Linear algebraic theory of partial coherence: discrete fields and measures of partial coherence.

Science.gov (United States)

Ozaktas, Haldun M; Yüksel, Serdar; Kutay, M Alper

2002-08-01

A linear algebraic theory of partial coherence is presented that allows precise mathematical definitions of concepts such as coherence and incoherence. This not only provides new perspectives and insights but also allows us to employ the conceptual and algebraic tools of linear algebra in applications. We define several scalar measures of the degree of partial coherence of an optical field that are zero for full incoherence and unity for full coherence. The mathematical definitions are related to our physical understanding of the corresponding concepts by considering them in the context of Young's experiment.

Dynamic isoperimetry and the geometry of Lagrangian coherent structures

International Nuclear Information System (INIS)

Froyland, Gary

2015-01-01

The study of transport and mixing processes in dynamical systems is particularly important for the analysis of mathematical models of physical systems. We propose a novel, direct geometric method to identify subsets of phase space that remain strongly coherent over a finite time duration. This new method is based on a dynamic extension of classical (static) isoperimetric problems; the latter are concerned with identifying submanifolds with the smallest boundary size relative to their volume.The present work introduces dynamic isoperimetric problems; the study of sets with small boundary size relative to volume as they are evolved by a general dynamical system. We formulate and prove dynamic versions of the fundamental (static) isoperimetric (in)equalities; a dynamic Federer–Fleming theorem and a dynamic Cheeger inequality. We introduce a new dynamic Laplace operator and describe a computational method to identify coherent sets based on eigenfunctions of the dynamic Laplacian.Our results include formal mathematical statements concerning geometric properties of finite-time coherent sets, whose boundaries can be regarded as Lagrangian coherent structures. The computational advantages of our new approach are a well-separated spectrum for the dynamic Laplacian, and flexibility in appropriate numerical approximation methods. Finally, we demonstrate that the dynamic Laplace operator can be realised as a zero-diffusion limit of a newly advanced probabilistic transfer operator method [9] for finding coherent sets, which is based on small diffusion. Thus, the present approach sits naturally alongside the probabilistic approach [9], and adds a formal geometric interpretation. (paper)

Prolonged pain and disability are common after rib fractures.

Science.gov (United States)

Fabricant, Loic; Ham, Bruce; Mullins, Richard; Mayberry, John

2013-05-01

The contribution of rib fractures to prolonged pain and disability may be underappreciated and undertreated. Clinicians are traditionally taught that the pain and disability of rib fractures resolves in 6 to 8 weeks. This study was a prospective observation of 203 patients with rib fractures at a level 1 trauma center. Chest wall pain was evaluated by the McGill Pain Questionnaire (MPQ) pain rating index (PRI) and present pain intensity (PPI). Prolonged pain was defined as a PRI of 8 or more at 2 months after injury. Prolonged disability was defined as a decrease in 1 or more levels of work or functional status at 2 months after injury. Predictors of prolonged pain and disability were determined by multivariate analysis. One hundred forty-five male patients and 58 female patients with a mean injury severity score (ISS) of 20 (range, 1 to 59) had a mean of 5.4 rib fractures (range, 1 to 29). Forty-four (22%) patients had bilateral fractures, 15 (7%) had flail chest, and 92 (45%) had associated injury. One hundred eighty-seven patients were followed 2 months or more. One hundred ten (59%) patients had prolonged chest wall pain and 142 (76%) had prolonged disability. Among 111 patients with isolated rib fractures, 67 (64%) had prolonged chest wall pain and 69 (66%) had prolonged disability. MPQ PPI was predictive of prolonged pain (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.4 to 2.5), and prolonged disability (OR, 2.2; 95% CI, 1.5 to 3.4). The presence of significant associated injuries was predictive of prolonged disability (OR, 5.9; 95% CI, 1.4 to 29). Prolonged chest wall pain is common, and the contribution of rib fractures to disability is greater than traditionally expected. Further investigation into more effective therapies that prevent prolonged pain and disability after rib fractures is needed. Copyright © 2013 Elsevier Inc. All rights reserved.

Mitigating prolonged QT interval in cancer nanodrug development for accelerated clinical translation.

Science.gov (United States)

Ranjan, Amalendu P; Mukerjee, Anindita; Helson, Lawrence; Vishwanatha, Jamboor K

2013-12-14

Cardiac toxicity is the foremost reason for drug discontinuation from development to clinical evaluation and post market surveillance [Fung 35:293-317, 2001; Piccini 158:317-326 2009]. The Food and Drug Administration (FDA) has rejected many potential pharmaceutical agents due to QT prolongation effects. Since drug development and FDA approval takes an enormous amount of time, money and effort with high failure rates, there is an increased focus on rescuing drugs that cause QT prolongation. If these otherwise safe and potent drugs were formulated in a unique way so as to mitigate the QT prolongation associated with them, these potent drugs may get FDA approval for clinical use. Rescuing these compounds not only benefit the patients who need them but also require much less time and money thus leading to faster clinical translation. In this study, we chose curcumin as our drug of choice since it has been shown to posses anti-tumor properties against various cancers with limited toxicity. The major limitations with this pharmacologically active drug are (a) its ability to prolong QT by inhibiting the hERG channel and (b) its low bioavailability. In our previous studies, we found that lipids have protective actions against hERG channel inhibition and therefore QT prolongation. Results of the manual patch clamp assay of HEK 293 cells clearly illustrated that our hybrid nanocurcumin formulation prevented the curcumin induced inhibition of hERG K+ channel at concentrations higher than the therapeutic concentrations of curcumin. Comparing the percent inhibition, the hybrid nanocurcumin limited inhibition to 24.8% at a high curcumin equivalent concentration of 18 μM. Liposomal curcumin could only decrease this inhibition upto 30% only at lower curcumin concentration of 6 μM but not at 18 μM concentration. Here we show a curcumin encapsulated lipopolymeric hybrid nanoparticle formulation which could protect against QT prolongation and also render increased

Analysis of interaction of some systems of the organism in the prolonged time after radiation exposure

International Nuclear Information System (INIS)

Akoev, I.G.

1978-01-01

Prolonged observations have been carried out of the composition of the form elements of white and red blood and hemoglobin content in dogs irradiated with the 400 R dose as well as of the nine factors of the punctate of bone marrow characterizing the division and ripening of red and white sprouts. On the base of comparison of dynamics of these fourteen indices the following conclusions on the sequence of inclusion and exclusion of hemopoiesis reserves have been made. The primacy of hemopoiesis to the red side exists always when there is an insufficient quantity of erythrocytes and hemoglobin in them important for organism. The first reserve to be mobilized and mostly used is the expansion of hemopoiesis spring-board, the second-accelerated passage of cells of the dividingand dividing-ripening pools. Later and for a very short time the number of mitoses increases in erythroblasts which directly reflects the reduction of their generative cycle

Optical Coherence and Quantum Optics

CERN Document Server

Mandel, Leonard

1995-01-01

This book presents a systematic account of optical coherence theory within the framework of classical optics, as applied to such topics as radiation from sources of different states of coherence, foundations of radiometry, effects of source coherence on the spectra of radiated fields, coherence theory of laser modes, and scattering of partially coherent light by random media. The book starts with a full mathematical introduction to the subject area and each chapter concludes with a set of exercises. The authors are renowned scientists and have made substantial contributions to many of the topi

On Longitudinal Spectral Coherence

DEFF Research Database (Denmark)

Kristensen, Leif

1979-01-01

It is demonstrated that the longitudinal spectral coherence differs significantly from the transversal spectral coherence in its dependence on displacement and frequency. An expression for the longitudinal coherence is derived and it is shown how the scale of turbulence, the displacement between ...... observation sites and the turbulence intensity influence the results. The limitations of the theory are discussed....

Non-Markovian response of ultrafast coherent electronic ring currents in chiral aromatic molecules in a condensed phase

International Nuclear Information System (INIS)

Mineo, H.; Lin, S. H.; Fujimura, Y.; Xu, J.; Xu, R. X.; Yan, Y. J.

2013-01-01

Results of a theoretical study on non-Markov response for femtosecond laser-driven coherent ring currents in chiral aromatic molecules embedded in a condensed phase are presented. Coherent ring currents are generated by coherent excitation of a pair of quasi-degenerated π-electronic excited states. The coherent electronic dynamical behaviors are strongly influenced by interactions between the electronic system and phonon bath in a condensed phase. Here, the bath correlation time is not instantaneous but should be taken to be a finite time in ultrashort time-resolved experiments. In such a case, Markov approximation breaks down. A hierarchical master equation approach for an improved semiclassical Drude dissipation model was adopted to examine the non-Markov effects on ultrafast coherent electronic ring currents of (P)-2,2 ′ -biphenol in a condensed phase. Time evolution of the coherent ring current derived in the hierarchical master equation approach was calculated and compared with those in the Drude model in the Markov approximation and in the static limit. The results show how non-Markovian behaviors in quantum beat signals of ring currents depend on the Drude bath damping constant. Effects of temperatures on ultrafast coherent electronic ring currents are also clarified

Prolonged delirium misdiagnosed as a mood disorder.

Science.gov (United States)

Cao, Fei; Salem, Haitham; Nagpal, Caesa; Teixeira, Antonio L

2017-01-01

Delirium can be conceptualized as an acute decline in cognitive function that typically lasts from hours to a few days. Prolonged delirium can also affect patients with multiple predisposing and/or precipitating factors. In clinical practice, prolonged delirium is often unrecognized, and can be misdiagnosed as other psychiatric disorders. We describe a case of a 59-year-old male presenting with behavioral and cognitive symptoms that was first misdiagnosed as a mood disorder in a general hospital setting. After prolonged delirium due to multiple factors was confirmed, the patient was treated accordingly with symptomatic management. He evolved with progressive improvement of his clinical status. Early diagnosis and management of prolonged delirium are important to improve patient prognosis and avoid iatrogenic measures.

Simultaneous measurements of global vibrational spectra and dephasing times of molecular vibrational modes by broadband time-resolved coherent anti-Stokes Raman scattering spectrography

International Nuclear Information System (INIS)

Yin Jun; Yu Ling-Yao; Liu Xing; Wan Hui; Lin Zi-Yang; Niu Han-Ben

2011-01-01

In broadband coherent anti-Stokes Raman scattering (CARS) spectroscopy with supercontinuum (SC), the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of various spectral components of SC in an enough bandwidth. By numerical simulations, the optimal experimental conditions for improving the SC are obtained. The broadband time-resolved CARS spectrography based on the SC with required temporal and spectral distributions is realised. The global molecular vibrational spectrum with well suppressed nonresonant background noise can be obtained in a single measurement. At the same time, the measurements of dephasing times of various molecular vibrational modes can be conveniently achieved from intensities of a sequence of time-resolved CARS signals. It will be more helpful to provide a complete picture of molecular vibrations, and to exhibit a potential to understand not only both the solvent dynamics and the solute-solvent interactions, but also the mechanisms of chemical reactions in the fields of biology, chemistry and material science. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Socio-demographic correlates of prolonged television viewing time in Australian men and women: the AusDiab study.

Science.gov (United States)

Clark, Bronwyn Kay; Sugiyama, Takemi; Healy, Genevieve N; Salmon, Jo; Dunstan, David W; Shaw, Jonathan E; Zimmet, Paul Z; Owen, Neville

2010-09-01

Sedentary behaviors, particularly television viewing (TV) time, are associated with adverse health outcomes in adults, independent of physical activity levels. These associations are stronger and more consistent for women than for men. Multivariate regression models examined the sociodemographic correlates of 2 categories of TV time (≥ 2 hours/day and ≥ 4 hours/day); in a large, population-based sample of Australian adults (4950 men, 6001 women; mean age 48.1 years, range 25-91) who participated in the 1999/2000 Australian Diabetes, Obesity, and Lifestyle (AusDiab) study. Some 46% of men and 40% of women watched ≥ 2 hours TV/day; 9% and 6% respectively watched ≥ 4 hours/day. For both men and women, ≥ 2 hours TV/day was associated with less than tertiary education, living outside of state capital cities, and having no paid employment. For women, mid and older age (45-64 and 65+) were also significant correlates of ≥ 2 hours TV/day. Similar patterns of association were observed in those viewing ≥ 4 hours/day. Prolonged TV time is associated with indices of social disadvantage and older age. These findings can inform the understanding of potential contextual influences and guide preventive initiatives.

Extensive deep vein thrombosis following prolonged gaming ('gamer's thrombosis'): a case report.

Science.gov (United States)

Chang, Hsien-Cheng Leon; Burbridge, Hayley; Wong, Conroy

2013-10-08

The average time spent playing video games is increasing. Prolonged immobility associated with gaming may therefore be an important risk factor for venous thromboembolism. We report a case of deep vein thrombosis associated with prolonged playing of PlayStation® games. A 31-year-old Caucasian man, an exterior painter, presented with a three-day history of left leg pain and swelling after playing PlayStation® games for almost eight hours a day for four consecutive days. Doppler ultrasound of the left leg confirmed extensive left leg deep venous thrombosis requiring thrombolysis and anticoagulation. Video gaming should be considered a risk factor for venous thromboembolism. Further studies are needed to estimate the degree of risk associated with prolonged periods of playing video games, and education for preventing venous thrombosis should be provided to gamers.

Dominant Lid Tectonics behaviour of continental lithosphere in Precambrian times: Palaeomagnetism confirms prolonged quasi-integrity and absence of supercontinent cycles

Directory of Open Access Journals (Sweden)

J.D.A. Piper

2018-01-01

Full Text Available Although Plate Tectonics cannot be effectively tested by palaeomagnetism in the Precambrian aeon due to the paucity of high precision poles spanning such a long time period, the possibility of Lid Tectonics is eminently testable because it seeks accordance of the wider dataset over prolonged intervals of time; deficiencies and complexities in the data merely contribute to dispersion. Accordance of palaeomagnetic poles across a quasi-integral continental crust for time periods of up to thousands of millions of years, together with recognition of very long intervals characterised by minimal polar motions (∼2.6–2.0, ∼1.5–1.25 and ∼0.75–0.6 Ga has been used to demonstrate that Lid Tectonics dominated this aeon. The new PALEOMAGIA database is used to refine a model for the Precambrian lid incorporating a large quasi-integral crescentric core running from South-Central Africa through Laurentia to Siberia with peripheral cratons subject to reorganisation at ∼2.1, ∼1.6 and ∼1.1 Ga. The model explains low levels of tidal friction, reduced heat balance, unique petrologic and isotopic signatures, and the prolonged crustal stability of Earth's “Middle Age”, whilst density concentrations of the palaeomagnetic poles show that the centre of the continental lid was persistently focussed near Earth's rotation axis from ∼2.8 to 0.6 Ga. The exception was the ∼2.7–2.2 Ga interval defined by ∼90° polar movements which translated the periphery of the lid to the rotation pole for this quasi-static period, a time characterised by glaciation and low levels of magmatic activity; the ∼2.7 Ga shift correlates with key interval of mid-Archaean crustal growth to some 60–70% of the present volume and REE signatures whilst the ∼2.2 Ga shift correlates with the Lomagundi δ13 C and Great Oxygenation events. The palaeomagnetic signature of breakup of the lid at ∼0.6 Ga is recorded by the world-wide Ediacaran development of passive

Multi-Channel Optical Coherence Elastography Using Relative and Absolute Shear-Wave Time of Flight

DEFF Research Database (Denmark)

Elyas, Eli; Grimwood, Alex; Erler, Janine Terra

2017-01-01

a commercial four-channel swept-source OCT system. Shear-wave time of arrival (TOA) was detected by tracking the axial OCT-speckle motion using cross-correlation methods. Shear-wave speed was then calculated from inter-channel differences of TOA for a single burst (the relative TOA method) and compared......Elastography, the imaging of elastic properties of soft tissues, is well developed for macroscopic clinical imaging of soft tissues and can provide useful information about various pathological processes which is complementary to that provided by the original modality. Scaling down...... of this technique should ply the field of cellular biology with valuable information with regard to elastic properties of cells and their environment. This paper evaluates the potential to develop such a tool by modifying a commercial optical coherence tomography (OCT) device to measure the speed of shear waves...

QT interval prolongation associated with sibutramine treatment

Science.gov (United States)

Harrison-Woolrych, Mira; Clark, David W J; Hill, Geraldine R; Rees, Mark I; Skinner, Jonathan R

2006-01-01

Aims To investigate a possible association of sibutramine with QT interval prolongation. Methods Post-marketing surveillance using prescription event monitoring in the New Zealand Intensive Medicines Monitoring Programme (IMMP) identified a case of QT prolongation and associated cardiac arrest in a patient taking sibutramine for 25 days. This patient was further investigated, including genotyping for long QT syndrome. Other IMMP case reports suggesting arrhythmias associated with sibutramine were assessed and further reports were obtained from the World Health Organisation (WHO) adverse drug reactions database. Results The index case displayed a novel mutation in a cardiac potassium channel subunit gene, KCNQ1, which is likely to prolong cardiac membrane depolarization and increase susceptibility to long QT intervals. Assessment of further IMMP reports identified five additional patients who experienced palpitations associated with syncope or presyncopal symptoms, one of whom had a QTc at the upper limit of normal. Assessment of reports from the WHO database identified three reports of QT prolongation and one fatal case of torsade de pointes in a patient also taking cisapride. Conclusions This case series suggests that sibutramine may be associated with QT prolongation and related dysrhythmias. Further studies are required, but in the meantime we would recommend that sibutramine should be avoided in patients with long QT syndrome and in patients taking other medicines that may prolong the QT interval. PMID:16542208

On P-coherent endomorphism rings

Indian Academy of Sciences (India)

A ring is called right -coherent if every principal right ideal is finitely presented. Let M R be a right -module. We study the -coherence of the endomorphism ring of M R . It is shown that is a right -coherent ring if and only if every endomorphism of M R has a pseudokernel in add M R ; S is a left -coherent ring if and ...

Coherent changes of multifractal properties of continuous acoustic emission at failure of heterogeneous materials

Science.gov (United States)

Panteleev, Ivan; Bayandin, Yuriy; Naimark, Oleg

2017-12-01

This work performs a correlation analysis of the statistical properties of continuous acoustic emission recorded in different parts of marble and fiberglass laminate samples under quasi-static deformation. A spectral coherent measure of time series, which is a generalization of the squared coherence spectrum on a multidimensional series, was chosen. The spectral coherent measure was estimated in a sliding time window for two parameters of the acoustic emission multifractal singularity spectrum: the spectrum width and the generalized Hurst exponent realizing the maximum of the singularity spectrum. It is shown that the preparation of the macrofracture focus is accompanied by the synchronization (coherent behavior) of the statistical properties of acoustic emission in allocated frequency intervals.

Array-Enhanced Coherence Resonance: Nontrivial Effects of Heterogeneity and Spatial Independence of Noise

International Nuclear Information System (INIS)

Zhou, Changsong; Kurths, Juergen; Hu, Bambi

2001-01-01

We demonstrate the effect of coherence resonance in a heterogeneous array of coupled Fitz Hugh--Nagumo neurons. It is shown that coupling of such elements leads to a significantly stronger coherence compared to that of a single element. We report nontrivial effects of parameter heterogeneity and spatial independence of noise on array-enhanced coherence resonance; especially, we find that (i) the coherence increases as spatial correlation of the noise decreases, and (ii) inhomogeneity in the parameters of the array enhances the coherence. Our results have the implication that generic heterogeneity and background noise can play a constructive role to enhance the time precision of firing in neural systems

Licence prolongations of US nuclear power plants

International Nuclear Information System (INIS)

2004-04-01

Licences of US nuclear reactors were initially attributed for a 40 years duration. However, the vast majority of the reactors can benefit of a licence prolongation for a period of 20 years maximum. This article recalls first the procedure to follow for the licence prolongation demands (safety analysis, components aging, environmental impact statement), and then it makes a status of the accepted prolongations, of the demands under examination, and of the demands that should be presented in the next 5 years. (J.S.)

A Study of Coherent Structures using Wavelet Analysis

Energy Technology Data Exchange (ETDEWEB)

Kaspersen, J H

1996-05-01

Turbulence is important in many fields of engineering, for example in estimating drag or minimizing drag on surfaces. It is known that turbulent flows contain coherent structures, which implies that a turbulent shear flow can be decomposed into coherent structures and random motion. It is generally accepted that coherent structures are responsible for significant transport of mass, heat and momentum. This doctoral thesis presents and discusses a new algorithm to detect coherent structures based on Wavelet transformations, a transform similar to the Fourier transform but providing information on both frequency and scale. The new detection scheme does not require any predefined threshold or integration time, and its general performance is found to be very good. Wind tunnel experiments were performed to obtain data for analysis. Scalograms resulting from the Wavelet transform show clearly that coherent structures exist in turbulent flows. These structures are shown to contribute considerably to the shear stresses. The contribution from the organized motion to the normal stresses close to the wall appears to be considerably smaller. Direct Navier Stokes (DNS) channel flow seems to be more organized than Zero Pressure Gradient (ZPG) flows. The topology of ZPG flows was studied using a multiple hot wire arrangement and conditionally averaged streamlines based on detections from the Wavelet method are presented. It is shown that the coherent structures produce large amounts of both vorticity and strain at the detection point. 56 refs., 92 figs., 3 tabs.

Driving a mechanical resonator into coherent states via random measurements

International Nuclear Information System (INIS)

Garcia, Ll; Wu, L-A; Chhajlany, R W; Li, Y

2013-01-01

We propose dynamical schemes to engineer coherent states of a mechanical resonator (MR) coupled to an ancillary, superconducting flux qubit. The flux qubit, when repeatedly projected on to its ground state, drives the MR into a coherent state in probabilistic, albeit heralded fashion. Assuming no operations on the state of the MR during the protocol, coherent states are successfully generated only up to a certain value of the displacement parameter. This restriction can be overcome at the cost of a one-time operation on the initial state of the MR. We discuss the possibility of experimental realization of the presented schemes. (paper)

Coherent states of non-relativistic electron in the magnetic-solenoid field

Energy Technology Data Exchange (ETDEWEB)

Bagrov, V G [Department of Physics, Tomsk State University, 634050, Tomsk (Russian Federation); Gavrilov, S P; Filho, D P Meira [Institute of Physics, University of Sao Paulo (Brazil); Gitman, D M, E-mail: bagrov@phys.tsu.r, E-mail: gavrilovsergeyp@yahoo.co, E-mail: gitman@dfn.if.usp.b, E-mail: dmeira@dfn.if.usp.b [Institute of Physics, University of Sao Paulo, CP 66318, CEP 05315-970 Sao Paulo (Brazil)

2010-09-03

In the present work we construct coherent states in the magnetic-solenoid field, which is a superposition of the Aharonov-Bohm field and a collinear uniform magnetic field. In the problem under consideration there are two kinds of coherent states, those which correspond to classical trajectories which embrace the solenoid and those which do not. The constructed coherent states reproduce exactly classical trajectories, maintain their form under the time evolution and form a complete set of functions, which can be useful in semiclassical calculations. In the absence of the solenoid field these states are reduced to the well known in the case of uniform magnetic field Malkin-Man'ko coherent states.

Tracking coherent structures in massively-separated and turbulent flows

Science.gov (United States)

Rockwood, Matthew; Huang, Yangzi; Green, Melissa

2018-01-01

Coherent vortex structures are tracked in simulations of massively-separated and turbulent flows. Topological Lagrangian saddle points are found using intersections of the positive and negative finite-time Lyapunov exponent ridges, and these points are then followed in order to track individual coherent structure motion both in a complex interacting three-dimensional flow (turbulent channel) and during vortex formation (two-dimensional bluff body shedding). For a simulation of wall-bounded turbulence in a channel flow, tracking Lagrangian saddles shows that the average structure convection speed exhibits a similar trend as a previously published result based on velocity and pressure correlations, giving validity to the method. When this tracking method is applied in a study of a circular cylinder in cross-flow it shows that Lagrangian saddles rapidly accelerate away from the cylinder surface as the vortex sheds. This saddle behavior is compared with the time-resolved static pressure distribution on the circular cylinder, yielding locations on a cylinder surface where common sensors could detect this phenomenon, which is not available from force measurements or vortex circulation calculations. The current method of tracking coherent structures yields insight into the behavior of the coherent structures in both of the diverse flows presented, highlighting the breadth of its potential application.

Electromagnetic spatial coherence wavelets

International Nuclear Information System (INIS)

Castaneda, R.; Garcia-Sucerquia, J.

2005-10-01

The recently introduced concept of spatial coherence wavelets is generalized for describing the propagation of electromagnetic fields in the free space. For this aim, the spatial coherence wavelet tensor is introduced as an elementary amount, in terms of which the formerly known quantities for this domain can be expressed. It allows analyzing the relationship between the spatial coherence properties and the polarization state of the electromagnetic wave. This approach is completely consistent with the recently introduced unified theory of coherence and polarization for random electromagnetic beams, but it provides a further insight about the causal relationship between the polarization states at different planes along the propagation path. (author)

Coherent states in quantum mechanics

CERN Document Server

Rodrigues, R D L; Fernandes, D

2001-01-01

We present a review work on the coherent states is non-relativistic quantum mechanics analysing the quantum oscillators in the coherent states. The coherent states obtained via a displacement operator that act on the wave function of ground state of the oscillator and the connection with Quantum Optics which were implemented by Glauber have also been considered. A possible generalization to the construction of new coherent states it is point out.

Predictive factors for oropharyngeal dysphagia after prolonged orotracheal intubation.

Science.gov (United States)

Oliveira, Ana Carolina Martins de; Friche, Amélia Augusta de Lima; Salomão, Marina Silva; Bougo, Graziela Chamarelli; Vicente, Laélia Cristina Caseiro

2017-09-13

Lesions in the oral cavity, pharynx and larynx due to endotracheal intubation can cause reduction in the local motility and sensitivity, impairing the swallowing process, resulting in oropharyngeal dysphagia. To verify the predictive factors for the development of oropharyngeal dysphagia and the risk of aspiration in patients with prolonged orotracheal intubation admitted to an intensive care unit. This is an observational, analytical, cross-sectional and retrospective data collection study of 181 electronic medical records of patients submitted to prolonged orotracheal intubation. Data on age; gender; underlying disease; associated comorbidities; time and reason for orotracheal intubation; Glasgow scale on the day of the Speech Therapist assessment; comprehension; vocal quality; presence and severity of dysphagia; risk of bronchoaspiration; and the suggested oral route were collected. The data were analyzed through logistic regression. The level of significance was set at 5%, with a 95% Confidence Interval. The prevalence of dysphagia in this study was 35.9% and the risk of aspiration was 24.9%. As the age increased, the altered vocal quality and the degree of voice impairment increased the risk of the presence of dysphagia by 5-; 45.4- and 6.7-fold, respectively, and of aspiration by 6-; 36.4- and 4.8-fold. The increase in the time of orotracheal intubation increased the risk of aspiration by 5.5-fold. Patients submitted to prolonged intubation who have risk factors associated with dysphagia and aspiration should be submitted to an early speech-language/audiology assessment and receive appropriate and timely treatment. The recognition of these predictive factors by the entire multidisciplinary team can minimize the possibility of clinical complications inherent to the risk of dysphagia and aspiration in extubated patients. Copyright © 2017. Published by Elsevier Editora Ltda.

Editor's Choice - Prolonged ICU Length of Stay after AAA Repair: Analysis of Time Trends and Long-term Outcome.

Science.gov (United States)

Gavali, H; Mani, K; Tegler, G; Kawati, R; Covaciu, L; Wanhainen, A

2017-08-01

The aim of the study was to investigate the frequency and outcome of prolonged intensive care unit (ICU) length of stay (LOS) after abdominal aortic aneurysm (AAA) repair in the endovascular era. All patients operated on for AAA between 1999 and 2013 at Uppsala University hospital were identified. Data were retrieved from the Swedish Vascular registry, the Swedish Intensive Care registry, the National Population registry, and case records. Prolonged ICU LOS was defined as ≥ 48 h during the primary hospital stay. Patients surviving ≥ 48 h after AAA surgery were included in the analysis. A total of 725 patients were identified, of whom 707 (97.5%) survived ≥ 48 h; 563 (79.6%) underwent intact AAA repair and 144 (20.4%) ruptured AAA repair. A total of 548 patients (77.5%) required AAA repairs in 1999 to 7.3% in 2013 (p < .001) whereas the use of endovascular aortic repair (EVAR) increased from 6.9% in 1999 to 78.0% in 2013 (p < .001). The 30 day survival rate was 98.2% for those with < 48 h ICU stay versus 93.0% for 2-6 days versus 81.8% for ≥ 7 days (p < .001); the corresponding 90 day survival was 97.1% versus 86.1% versus 63.6% (p < .001) respectively. For patients surviving 90 days after repair, there was no difference in long-term survival between the groups. During the period of progressively increasing use of EVAR, a simultaneous significant reduction in frequency of prolonged ICU LOS occurred. Although prolonged ICU LOS was associated with a high short-term mortality, long-term outcome among those surviving the initial 90 days was less affected. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Coherent combination of ultrafast fiber amplifiers

International Nuclear Information System (INIS)

Hanna, Marc; Guichard, Florent; Druon, Frédéric; Georges, Patrick; Zaouter, Yoann; Papadopoulos, Dimitris N

2016-01-01

We review recent progress in coherent combining of femtosecond pulses amplified in optical fibers as a way to scale the peak and average power of ultrafast sources. Different methods of achieving coherent pulse addition in space (beam combining) and time (divided pulse amplification) domains are described. These architectures can be widely classified into active methods, where the relative phases between pulses are subject to a servomechanism, and passive methods, where phase matching is inherent to the geometry. Other experiments that combine pulses with different spectral contents, pulses that have been nonlinearly broadened or successive pulses from a mode-locked laser oscillator, are then presented. All these techniques allow access to unprecedented parameter range for fiber ultrafast sources. (topical review)

From quantum coherence to quantum correlations

Science.gov (United States)

Sun, Yuan; Mao, Yuanyuan; Luo, Shunlong

2017-06-01

In quantum mechanics, quantum coherence of a state relative to a quantum measurement can be identified with the quantumness that has to be destroyed by the measurement. In particular, quantum coherence of a bipartite state relative to a local quantum measurement encodes quantum correlations in the state. If one takes minimization with respect to the local measurements, then one is led to quantifiers which capture quantum correlations from the perspective of coherence. In this vein, quantum discord, which quantifies the minimal correlations that have to be destroyed by quantum measurements, can be identified as the minimal coherence, with the coherence measured by the relative entropy of coherence. To advocate and formulate this idea in a general context, we first review coherence relative to Lüders measurements which extends the notion of coherence relative to von Neumann measurements (or equivalently, orthonomal bases), and highlight the observation that quantum discord arises as minimal coherence through two prototypical examples. Then, we introduce some novel measures of quantum correlations in terms of coherence, illustrate them through examples, investigate their fundamental properties and implications, and indicate their applications to quantum metrology.

Entropic cohering power in quantum operations

Science.gov (United States)

Xi, Zhengjun; Hu, Ming-Liang; Li, Yongming; Fan, Heng

2018-02-01

Coherence is a basic feature of quantum systems and a common necessary condition for quantum correlations. It is also an important physical resource in quantum information processing. In this paper, using relative entropy, we consider a more general definition of the cohering power of quantum operations. First, we calculate the cohering power of unitary quantum operations and show that the amount of distributed coherence caused by non-unitary quantum operations cannot exceed the quantum-incoherent relative entropy between system of interest and its environment. We then find that the difference between the distributed coherence and the cohering power is larger than the quantum-incoherent relative entropy. As an application, we consider the distributed coherence caused by purification.

Experimental generation of optical coherence lattices

Energy Technology Data Exchange (ETDEWEB)

Chen, Yahong; Cai, Yangjian, E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China); Ponomarenko, Sergey A., E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [Department of Electrical and Computer Engineering, Dalhousie University, Halifax, Nova Scotia B3J 2X4 (Canada)

2016-08-08

We report experimental generation and measurement of recently introduced optical coherence lattices. The presented optical coherence lattice realization technique hinges on a superposition of mutually uncorrelated partially coherent Schell-model beams with tailored coherence properties. We show theoretically that information can be encoded into and, in principle, recovered from the lattice degree of coherence. Our results can find applications to image transmission and optical encryption.

Hilbert and Blaschke phases in the temporal coherence function of stationary broadband light.

Science.gov (United States)

Fernández-Pousa, Carlos R; Maestre, Haroldo; Torregrosa, Adrián J; Capmany, Juan

2008-10-27

We show that the minimal phase of the temporal coherence function gamma (tau) of stationary light having a partially-coherent symmetric spectral peak can be computed as a relative logarithmic Hilbert transform of its amplitude with respect to its asymptotic behavior. The procedure is applied to experimental data from amplified spontaneous emission broadband sources in the 1.55 microm band with subpicosecond coherence times, providing examples of degrees of coherence with both minimal and non-minimal phase. In the latter case, the Blaschke phase is retrieved and the position of the Blaschke zeros determined.

Coherent states in quantum mechanics

International Nuclear Information System (INIS)

Rodrigues, R. de Lima; Fernandes Junior, Damasio; Batista, Sheyla Marques

2001-12-01

We present a review work on the coherent states is non-relativistic quantum mechanics analysing the quantum oscillators in the coherent states. The coherent states obtained via a displacement operator that act on the wave function of ground state of the oscillator and the connection with Quantum Optics which were implemented by Glauber have also been considered. A possible generalization to the construction of new coherent states it is point out. (author)

Microstructure evolution during the precipitation and growth of fully coherent DO{sub 22} superlattice in an Ni-Cr-W alloy

Energy Technology Data Exchange (ETDEWEB)

Gao, Xiangyu [Stake Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an 710072 (China); Hu, Rui, E-mail: rhu@nwpu.edu.cn [Stake Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an 710072 (China); Li, Xiaolin [Stake Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Luo, Gongliao [Stake Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an 710072 (China)

2016-08-15

The ordering transformation occurring in a model Ni-Cr-W superalloy during prolonged exposure to proper temperature has been investigated systematically. It is demonstrated that nanometer-sized precipitates with a DO{sub 22} structure can precipitate in the Ni-Cr-W alloy by means of simple aging treatment at 650–700 °C. The mechanism of transformation to DO{sub 22} superlattice has been determined to be continuous ordering based on the results of high resolution transmission electron microscopy investigation and variation trend in Vickers microhardness. Different variants of DO{sub 22} phase can coexist in the matrix with no signs of overaging as aging time increases, indicating it has a high thermal stability. The precipitates of DO{sub 22} superlattice has been found to be of ellipsoidal shape which results in the greatest reduction of strain energy. The interfaces between DO{sub 22} precipitates and matrix have been revealed to be coherent at the atomic scale, resulting in considerable coherency strain attributing to the lattice misfit between DO{sub 22} particle and matrix. Because of the high-density nanometer-sized DO{sub 22} phase, the microhardness of the alloy has been improved remarkably after aging treatment. - Graphical abstract: Different variants of the DO{sub 22} superlattice can coexist in the matrix, and the interface between precipitate and the matrix remain coherence at the atomic scale. The three dimensional form of the DO{sub 22} precipitates constructed from three mutually perpendicular projections is an ellipsoidal stick, and the directions of elongations are along the longest axis of the unit cell for DO{sub 22} phase. - Highlights: •The DO{sub 22} phase precipitated in the Ni-Cr-W alloy has a high thermal stability. •The morphology of DO{sub 22} superlattice has been determined to be ellipsoid. •The interface between DO{sub 22} phase and matrix are fully coherent at the atomic scale. •Different variants of DO{sub 22} phase occur

Coherent Detection of Wavelength Division Multiplexed Phase-Modulated Radio-over-Fibre Signals

DEFF Research Database (Denmark)

Zibar, Darko; Yu, Xianbin; Peucheret, Christophe

2008-01-01

A WDM phase-modulated Radio-over-Fibre link using digital coherent detection is experimentally demonstrated. 3 times 50 Mb/s WDM transmission of a BPSK modulated 5 GHz RF carrier is achieved over 25 km.......A WDM phase-modulated Radio-over-Fibre link using digital coherent detection is experimentally demonstrated. 3 times 50 Mb/s WDM transmission of a BPSK modulated 5 GHz RF carrier is achieved over 25 km....

High-speed asynchronous optical sampling for high-sensitivity detection of coherent phonons

International Nuclear Information System (INIS)

Dekorsy, T; Taubert, R; Hudert, F; Schrenk, G; Bartels, A; Cerna, R; Kotaidis, V; Plech, A; Koehler, K; Schmitz, J; Wagner, J

2007-01-01

A new optical pump-probe technique is implemented for the investigation of coherent acoustic phonon dynamics in the GHz to THz frequency range which is based on two asynchronously linked femtosecond lasers. Asynchronous optical sampling (ASOPS) provides the performance of on all-optical oscilloscope and allows us to record optically induced lattice dynamics over nanosecond times with femtosecond resolution at scan rates of 10 kHz without any moving part in the set-up. Within 1 minute of data acquisition time signal-to-noise ratios better than 10 7 are achieved. We present examples of the high-sensitivity detection of coherent phonons in superlattices and of the coherent acoustic vibration of metallic nanoparticles

Optical coherence tomography findings of quinine poisoning

Directory of Open Access Journals (Sweden)

John Christoforidis

2011-01-01

Full Text Available John Christoforidis, Robert Ricketts, Theodore Loizos, Susie ChangThe Ohio State University College of Medicine, Columbus, OH, USAPurpose: To report a case of acute quinine poisoning, document acute and chronic macular changes with optical coherence tomography imaging and fluorescein angiography (FA, and to review the literature on ocular toxicity of quinine.Methods: A 32-year-old white female presented to our Emergency Department after ingesting over 7.5 g of quinine. She underwent a complete ophthalmologic examination, fluorescein angiography, Stratus time-domain optical coherence tomography (OCT, and electroretinography at 72 hours and 15 months postingestion. Stratus time-domain and Cirrus spectral-domain OCT, fundus autofluorescence, and FA were obtained at 28 months postingestion.Results: Fluorescein angiography at 72 hours postingestion revealed normal filling times and vasculature. OCT showed marked thickening of the inner retina bilaterally. At 15 and 28 months follow-up, fundus photography and fluorescein angiography demonstrated optic nerve pallor, severely attenuated retinal vessels while OCT showed inner retinal atrophy. Fundus autofluorescence did not reveal any retinal pigmentary abnormalities.Conclusions: Quinine toxicity as seen by OCT reveals increased thickness with inner retinal hyperreflectivity acutely with development of significant retinal atrophy in the long-term. Fundus autofluorescence reveals an intact retinal pigment epithelial layer at 28 months. These findings suggest that quinine poisoning may produce a direct toxic effect on the inner retina in the acute phase resulting in long-term retinal atrophy.Keywords: retinal, optical coherence tomography, quinine toxicity 

Experimental study of coherence vortices: Local properties of phase singularities in a spatial coherence function

DEFF Research Database (Denmark)

Wang, W.; Duan, Z.H.; Hanson, Steen Grüner

2006-01-01

By controlling the irradiance of an extended quasimonochromatic, spatially incoherent source, an optical field is generated that exhibits spatial coherence with phase singularities, called coherence vortices. A simple optical geometry for direct visualization of coherence vortices is proposed, an...

Prolonged Activated Clotting Time after Protamine Administration Does Not Indicate Residual Heparinization after Cardiopulmonary Bypass in Pediatric Open Heart Surgery.

Science.gov (United States)

Yamamoto, Tomohiro; Wolf, Hans-Gerd; Sinzobahamvya, Nicodème; Asfour, Boulos; Hraska, Victor; Schindler, Ehrenfried

2015-08-01

In open heart surgery, heparinization is commonly neutralized using an empirical heparin:protamine ratio ranging between 1:1 and 1:1.5. However, these ratios may result in protamine overdose that should be avoided for its negative side effects on the coagulation system. This study aimed to indicate the appropriate treatment for prolonged activated clotting time (ACT) after protamine administration following cardiopulmonary bypass (CPB) in pediatric open heart surgery by investigating the underlying reasons for it. Twenty-seven children (open heart surgery were included. Heparin was administered only before CPB (400 IU/kg) and in the pump priming volume for CPB (2,000 IU) and was neutralized by 1:1 protamine after CPB. The blood heparin concentration was measured using anti-Xa assay. ACT and blood concentrations of heparin, coagulation factors, thrombin-antithrombin complex, and prothrombin fragment 1 + 2 were assessed. A rotational thromboelastometry (ROTEM; Tem International GmbH, München, Bayern, Germany) was used to confirm the coagulation status and residual heparin after protamine administration. Anti-Xa assay showed that there is no residual heparin in the blood after 1:1 protamine administration. Nevertheless, ACT (128.89 ± 3.09 seconds before heparin administration) remained prolonged (177.14 ± 5.43 seconds at 10 minutes after protamine, 182.00 ± 5.90 seconds at 30 minutes after protamine). The blood concentrations of coagulation factors were significantly lower than those before heparin administration (p < 0.01). The low FIBTEM MCF of ROTEM (4.43 ± 0.32 mm) at 10 minutes after protamine indicated low fibrinogen concentration. Prolonged ACT after heparin neutralization by 1:1 protamine administration does not necessarily indicate residual heparin, but low blood concentrations of coagulation factors should be considered as a reason as well. Accordingly, supply of coagulation factors instead of additional protamine should be

Prenatal risk indicators of a prolonged pregnancy

DEFF Research Database (Denmark)

Olesen, Annette Wind; Westergaard, Jes Grabow; Olsen, Jørn

2006-01-01

BACKGROUND: Few prenatal risk factors of prolonged pregnancy, a pregnancy of 42 weeks or more, are known. The objective was to examine whether sociodemographic, reproductive, toxicologic, or medical health conditions were associated with the risk of prolonged pregnancy. METHODS: Data from...

Identification of individual coherent sets associated with flow trajectories using coherent structure coloring

Science.gov (United States)

Schlueter-Kuck, Kristy L.; Dabiri, John O.

2017-09-01

We present a method for identifying the coherent structures associated with individual Lagrangian flow trajectories even where only sparse particle trajectory data are available. The method, based on techniques in spectral graph theory, uses the Coherent Structure Coloring vector and associated eigenvectors to analyze the distance in higher-dimensional eigenspace between a selected reference trajectory and other tracer trajectories in the flow. By analyzing this distance metric in a hierarchical clustering, the coherent structure of which the reference particle is a member can be identified. This algorithm is proven successful in identifying coherent structures of varying complexities in canonical unsteady flows. Additionally, the method is able to assess the relative coherence of the associated structure in comparison to the surrounding flow. Although the method is demonstrated here in the context of fluid flow kinematics, the generality of the approach allows for its potential application to other unsupervised clustering problems in dynamical systems such as neuronal activity, gene expression, or social networks.

Quantum key distribution with a single photon from a squeezed coherent state

International Nuclear Information System (INIS)

Matsuoka, Masahiro; Hirano, Takuya

2003-01-01

Squeezing of the coherent state by optical parametric amplifier is shown to efficiently produce single-photon states with reduced multiphoton probabilities compared with the weak coherent light. It can be a better source for a longer-distance quantum key distribution and also for other quantum optical experiments. The necessary condition for a secure quantum key distribution given by Brassard et al. is analyzed as functions of the coherent-state amplitude and squeeze parameter. Similarly, the rate of the gained secure bits G after error correction and privacy amplification given by Luetkenhaus is calculated. Compared with the weak coherent light, it is found that G is about ten times larger and its high level continues on about two times longer distance. By improvement of the detector efficiency it is shown that the distance extends further. Measurement of the intensity correlation function and the relation to photon antibunching are discussed for the experimental verification of the single-photon generation

Average intensity and coherence properties of a partially coherent Lorentz-Gauss beam propagating through oceanic turbulence

Science.gov (United States)

Liu, Dajun; Wang, Guiqiu; Wang, Yaochuan

2018-01-01

Based on the Huygens-Fresnel integral and the relationship of Lorentz distribution and Hermite-Gauss function, the average intensity and coherence properties of a partially coherent Lorentz-Gauss beam propagating through oceanic turbulence have been investigated by using numerical examples. The influences of beam parameters and oceanic turbulence on the propagation properties are also discussed in details. It is shown that the partially coherent Lorentz-Gauss beam with smaller coherence length will spread faster in oceanic turbulence, and the stronger oceanic turbulence will accelerate the spreading of partially coherent Lorentz-Gauss beam in oceanic turbulence.

Does UTI cause prolonged jaundice in otherwise well infants?

Science.gov (United States)

Chowdhury, Tanzila; Kisat, Hamudi; Tullus, Kjell

2015-07-01

The symptoms of urinary tract infections in infants are very non-specific and have historically included prolonged hyperbilirubinaemia. We studied the results of routine urine samples in 319 infants with prolonged jaundice. Convincing findings of UTI was not found in any of these children even if one of them was treated with antibiotics after four consecutive urine cultures with different bacteria. A urine culture might thus not be an appropriate investigation in a child with prolonged jaundice without any other symptoms of UTI. • The symptoms of UTI in infancy are very non-specific. • Old studies suggest that prolonged hyperbilirubinaemia is one such symptom; more modern studies give more conflicting results. What is New: • Our study could not confirm that children with prolonged jaundice have an increased risk of UTI. • Routine urine testing is thus not needed in otherwise healthy infants with prolonged jaundice.

Sequential Coherence in Sentence Pairs Enhances Imagery during Comprehension: An Individual Differences Study.

Directory of Open Access Journals (Sweden)

Carol Madden-Lombardi

Full Text Available The present study investigates how sequential coherence in sentence pairs (events in sequence vs. unrelated events affects the perceived ability to form a mental image of the sentences for both auditory and visual presentations. In addition, we investigated how the ease of event imagery affected online comprehension (word reading times in the case of sequentially coherent and incoherent sentence pairs. Two groups of comprehenders were identified based on their self-reported ability to form vivid mental images of described events. Imageability ratings were higher and faster for pairs of sentences that described events in coherent sequences rather than non-sequential events, especially for high imagers. Furthermore, reading times on individual words suggested different comprehension patterns with respect to sequence coherence for the two groups of imagers, with high imagers activating richer mental images earlier than low imagers. The present results offer a novel link between research on imagery and discourse coherence, with specific contributions to our understanding of comprehension patterns for high and low imagers.

Coherence Properties of Individual Femtosecond Pulses of an X-ray Free-Electron Laser

Energy Technology Data Exchange (ETDEWEB)

Vartanyants, I.A.; /DESY /Moscow Phys. Eng. Inst.; Singer, A.; Mancuso, A.P.; Yefanov, O.M.; /DESY; Sakdinawat, A.; Liu, Y.; Bang, E.; /UC, Berkeley; Williams, G.J.; /SLAC; Cadenazzi, G.; Abbey, B.; /Melbourne U.; Sinn, H.; /European XFEL, Hamburg; Attwood, D.; /UC, Berkeley; Nugent, K.A.; /Melbourne U.; Weckert, E.; /DESY; Wang, T.; Zhu, D.; Wu, B.; Graves, C.; Scherz, A.; Turner, J.J.; Schlotter, W.F.; /SLAC /LERMA, Ivry /Zurich, ETH /LBL, Berkeley /ANL, APS /Argonne /SLAC /LLNL, Livermore /Latrobe U. /SLAC /SLAC /European XFEL, Hamburg /SLAC /Hamburg U.

2012-06-06

Measurements of the spatial and temporal coherence of single, femtosecond x-ray pulses generated by the first hard x-ray free-electron laser, the Linac Coherent Light Source, are presented. Single-shot measurements were performed at 780 eV x-ray photon energy using apertures containing double pinholes in 'diffract-and-destroy' mode. We determined a coherence length of 17 {micro}m in the vertical direction, which is approximately the size of the focused Linac Coherent Light Source beam in the same direction. The analysis of the diffraction patterns produced by the pinholes with the largest separation yields an estimate of the temporal coherence time of 0.55 fs. We find that the total degree of transverse coherence is 56% and that the x-ray pulses are adequately described by two transverse coherent modes in each direction. This leads us to the conclusion that 78% of the total power is contained in the dominant mode.

Coherent communication with continuous quantum variables

Science.gov (United States)

Wilde, Mark M.; Krovi, Hari; Brun, Todd A.

2007-06-01

The coherent bit (cobit) channel is a resource intermediate between classical and quantum communication. It produces coherent versions of teleportation and superdense coding. We extend the cobit channel to continuous variables by providing a definition of the coherent nat (conat) channel. We construct several coherent protocols that use both a position-quadrature and a momentum-quadrature conat channel with finite squeezing. Finally, we show that the quality of squeezing diminishes through successive compositions of coherent teleportation and superdense coding.

Adaptive estimation of a time-varying phase with coherent states: Smoothing can give an unbounded improvement over filtering

Science.gov (United States)

Laverick, Kiarn T.; Wiseman, Howard M.; Dinani, Hossein T.; Berry, Dominic W.

2018-04-01

The problem of measuring a time-varying phase, even when the statistics of the variation is known, is considerably harder than that of measuring a constant phase. In particular, the usual bounds on accuracy, such as the 1 /(4 n ¯) standard quantum limit with coherent states, do not apply. Here, by restricting to coherent states, we are able to analytically obtain the achievable accuracy, the equivalent of the standard quantum limit, for a wide class of phase variation. In particular, we consider the case where the phase has Gaussian statistics and a power-law spectrum equal to κp -1/|ω| p for large ω , for some p >1 . For coherent states with mean photon flux N , we give the quantum Cramér-Rao bound on the mean-square phase error as [psin(π /p ) ] -1(4N /κ ) -(p -1 )/p . Next, we consider whether the bound can be achieved by an adaptive homodyne measurement in the limit N /κ ≫1 , which allows the photocurrent to be linearized. Applying the optimal filtering for the resultant linear Gaussian system, we find the same scaling with N , but with a prefactor larger by a factor of p . By contrast, if we employ optimal smoothing we can exactly obtain the quantum Cramér-Rao bound. That is, contrary to previously considered (p =2 ) cases of phase estimation, here the improvement offered by smoothing over filtering is not limited to a factor of 2 but rather can be unbounded by a factor of p . We also study numerically the performance of these estimators for an adaptive measurement in the limit where N /κ is not large and find a more complicated picture.

Volitional Control of Neuromagnetic Coherence

Directory of Open Access Journals (Sweden)

Matthew D Sacchet

2012-12-01

Full Text Available Coherence of neural activity between circumscribed brain regions has been implicated as an indicator of intracerebral communication in various cognitive processes. While neural activity can be volitionally controlled with neurofeedback, the volitional control of coherence has not yet been explored. Learned volitional control of coherence could elucidate mechanisms of associations between cortical areas and its cognitive correlates and may have clinical implications. Neural coherence may also provide a signal for brain-computer interfaces (BCI. In the present study we used the Weighted Overlapping Segment Averaging (WOSA method to assess coherence between bilateral magnetoencephalograph (MEG sensors during voluntary digit movement as a basis for BCI control. Participants controlled an onscreen cursor, with a success rate of 124 of 180 (68.9%, sign-test p < 0.001 and 84 out of 100 (84%, sign-test p < 0.001. The present findings suggest that neural coherence may be volitionally controlled and may have specific behavioral correlates.

Coherent Radiation of Electron Cloud

International Nuclear Information System (INIS)

Heifets, S.

2004-01-01

The electron cloud in positron storage rings is pinched when a bunch passes by. For short bunches, the radiation due to acceleration of electrons of the cloud is coherent. Detection of such radiation can be used to measure the density of the cloud. The estimate of the power and the time structure of the radiated signal is given in this paper

Coherence and dephasing in self-assembled quantum dots

DEFF Research Database (Denmark)

Hvam, Jørn Märcher; Leosson, K.; Birkedal, Dan

2003-01-01

We measured dephasing times in InGaAl/As self-assembled quantum dots at low temperature using degenerate four-wave mixing. At 0K, the coherence time of the quantum dots is lifetime limited, whereas at finite temperatures pure dephasing by exciton-phonon interactions governs the quantum dot...

Operational resource theory of total quantum coherence

Science.gov (United States)

Yang, Si-ren; Yu, Chang-shui

2018-01-01

Quantum coherence is an essential feature of quantum mechanics and is an important physical resource in quantum information. Recently, the resource theory of quantum coherence has been established parallel with that of entanglement. In the resource theory, a resource can be well defined if given three ingredients: the free states, the resource, the (restricted) free operations. In this paper, we study the resource theory of coherence in a different light, that is, we consider the total coherence defined by the basis-free coherence maximized among all potential basis. We define the distillable total coherence and the total coherence cost and in both the asymptotic regime and the single-copy regime show the reversible transformation between a state with certain total coherence and the state with the unit reference total coherence. Extensively, we demonstrate that the total coherence can also be completely converted to the total correlation with the equal amount by the free operations. We also provide the alternative understanding of the total coherence, respectively, based on the entanglement and the total correlation in a different way.

Simulation of partially coherent light propagation using parallel computing devices

Science.gov (United States)

Magalhães, Tiago C.; Rebordão, José M.

2017-08-01

Light acquires or loses coherence and coherence is one of the few optical observables. Spectra can be derived from coherence functions and understanding any interferometric experiment is also relying upon coherence functions. Beyond the two limiting cases (full coherence or incoherence) the coherence of light is always partial and it changes with propagation. We have implemented a code to compute the propagation of partially coherent light from the source plane to the observation plane using parallel computing devices (PCDs). In this paper, we restrict the propagation in free space only. To this end, we used the Open Computing Language (OpenCL) and the open-source toolkit PyOpenCL, which gives access to OpenCL parallel computation through Python. To test our code, we chose two coherence source models: an incoherent source and a Gaussian Schell-model source. In the former case, we divided into two different source shapes: circular and rectangular. The results were compared to the theoretical values. Our implemented code allows one to choose between the PyOpenCL implementation and a standard one, i.e using the CPU only. To test the computation time for each implementation (PyOpenCL and standard), we used several computer systems with different CPUs and GPUs. We used powers of two for the dimensions of the cross-spectral density matrix (e.g. 324, 644) and a significant speed increase is observed in the PyOpenCL implementation when compared to the standard one. This can be an important tool for studying new source models.

The Winter Procedure as Management for Prolonged Low-Flow Priapism: A Case Report

Directory of Open Access Journals (Sweden)

Hsi-Lin Hsiao

2007-10-01

Full Text Available Priapism is a prolonged penile erection that is not associated with sexual stimulation. Although the time course has not been formally defined, it is usually considered to be one that lasts for more than 4–6 hours. Low-flow (ischemic priapism is usually associated with sickle cell disease, hemoglobinopathies, neoplastic syndrome, anticoagulant therapy, psychotropic medication or idiopathic causes. Here, we report a case of prolonged low-flow priapism lasting for 2 weeks, which was successfully treated with the Winter procedure after several attempts of conservative treatment. Although the potency remains unclear and the patient needs a longer period of follow-up, the case reported here still shows that prolonged low-flow priapism can be successfully treated with the Winter procedure when conservative treatments fail.

High resolution coherence domain depth-resolved nailfold capillaroscopy based on correlation mapping optical coherence tomography

Science.gov (United States)

Subhash, Hrebesh M.; O'Gorman, Sean; Neuhaus, Kai; Leahy, Martin

2014-03-01

In this paper we demonstrate a novel application of correlation mapping optical coherence tomography (cm-OCT) for volumetric nailfold capillaroscopy (NFC). NFC is a widely used non-invasive diagnostic method to analyze capillary morphology and microvascular abnormalities of nailfold area for a range of disease conditions. However, the conventional NFC is incapable of providing volumetric imaging, when volumetric quantitative microangiopathic parameters such as plexus morphology, capillary density, and morphologic anomalies of the end row loops most critical. cm-OCT is a recently developed well established coherence domain magnitude based angiographic modality, which takes advantage of the time-varying speckle effect, which is normally dominant in the vicinity of vascular regions compared to static tissue region. It utilizes the correlation coefficient as a direct measurement of decorrelation between two adjacent B-frames to enhance the visibility of depth-resolved microcirculation.

Coherent counter-steaming electrostatic wave Raman interaction system utilizing opposing electron beams for the production of coherent microwaves in plasmas

International Nuclear Information System (INIS)

Leiby, C.C. Jr.; Prasad, B.

1977-01-01

The generation of controlled, electromagnetic, coherent, microwave radiation from a warm, uniform plasma at approximately twice the electron plasma frequency by means of two oppositely directed streams of high energy electrons and the coupling of the resulting coherent, electromagnetic radiation from a cavity resonator into external circuitry, wherein the two opposing streams of high energy electrons directed into the warm, uniform plasma result in a conversion of electron beam and plasma energies into transverse electromagnetic radiation from 10 to 100 times that which is possible with a single electron beam-plasma system. 7 claims, 4 figures

Pharmacokinetics of prolonged-release tacrolimus and implications for use in solid organ transplant recipients.

Science.gov (United States)

Tanzi, Maria G; Undre, Nasrullah; Keirns, James; Fitzsimmons, William E; Brown, Malcolm; First, M Roy

2016-08-01

Prolonged-release tacrolimus was developed as a once-daily formulation with ethylcellulose as the excipient, resulting in slower release and reduction in peak concentration (Cmax ) for a given dose compared with immediate-release tacrolimus, which is administered twice daily. This manuscript reviews pharmacokinetic information on prolonged-release tacrolimus in healthy subjects, in transplant recipients converted from immediate-release tacrolimus, and in de novo kidney and liver transplant recipients. As with the immediate-release formulation, prolonged-release tacrolimus shows a strong correlation between trough concentration (Cmin ) and area under the 24-hour time-concentration curve (AUC24 ), indicating that trough whole blood concentrations provide an accurate measure of drug exposure. We present the pharmacokinetic similarities and differences between the two formulations, so that prescribing physicians will have a better understanding of therapeutic drug monitoring in patients receiving prolonged-release tacrolimus. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Tailoring Quantum Dot Assemblies to Extend Exciton Coherence Times and Improve Exciton Transport

Science.gov (United States)

Seward, Kenton; Lin, Zhibin; Lusk, Mark

2012-02-01

The motion of excitons through nanostructured assemblies plays a central role in a wide range of physical phenomena including quantum computing, molecular electronics, photosynthetic processes, excitonic transistors and light emitting diodes. All of these technologies are severely handicapped, though, by quasi-particle lifetimes on the order of a nanosecond. The movement of excitons must therefore be as efficient as possible in order to move excitons meaningful distances. This is problematic for assemblies of small Si quantum dots (QDs), where excitons quickly localize and entangle with dot phonon modes. Ensuing exciton transport is then characterized by a classical random walk reduced to very short distances because of efficient recombination. We use a combination of master equation (Haken-Strobl) formalism and density functional theory to estimate the rate of decoherence in Si QD assemblies and its impact on exciton mobility. Exciton-phonon coupling and Coulomb interactions are calculated as a function of dot size, spacing and termination to minimize the rate of intra-dot phonon entanglement. This extends the time over which more efficient exciton transport, characterized by partial coherence, can be maintained.

Prolonged labour as indication for emergency caesarean section

DEFF Research Database (Denmark)

Maaløe, Nanna; Sorensen, B L; Onesmo, R

2012-01-01

To audit the quality of obstetric management preceding emergency caesarean sections for prolonged labour.......To audit the quality of obstetric management preceding emergency caesarean sections for prolonged labour....

Prolonged Pregnancy: Methods, Causal Determinants and Outcome

DEFF Research Database (Denmark)

Olesen, Annette Wind

) to study the incidence of prolonged pregnancy as a function of methods for determining gestational age; 2) to determine the risk of obstetrical and fetal complications in prolonged pregnancy; 3) to validate the self-reported gestational age in the National Birth Cohort; 4) to determine whether...... an ultrasound scan in the first or second trimester, or menstrual history was best at predicting the day of delivery; 5) to study the risk of recurrence of prolonged pregnancy as a function of change in male partner, social status and municipality; and 6) to detect prenatal risk indicators of prolonged...... of perinatal and obstetrical complications was high in post-term delivery compared to term delivery (OR between 1.2 and 3.1). The risk of perinatal death (OR=1.36 (1.08-1.72)) was also higher in the post-term group (I). The self-reported gestational ages in the National Birth Cohort correlated well with data...

Coherence in electron energy loss spectrometry

International Nuclear Information System (INIS)

Schattschneider, P.; Werner, W.S.M.

2005-01-01

Coherence effects in electron energy loss spectrometry (EELS) and in energy filtering are largely neglected although they occur frequently due to Bragg scattering in crystals. We discuss how coherence in the inelastically scattered wave field can be described by the mixed dynamic form factor (MDFF), and how it relates to the density matrix of the scattered electrons. Among the many aspects of 'inelastic coherence' are filtered high-resolution images, dipole-forbidden transitions, coherence in plasma excitations, errors in chemical microanalysis, coherent double plasmons, and circular dichroism

The effects of sodium bicarbonate during prolonged cardiopulmonary resuscitation.

Science.gov (United States)

Weng, Yi-Ming; Wu, Shih-Hao; Li, Wen-Cheng; Kuo, Chan-Wei; Chen, Shou-Yen; Chen, Jih-Chang

2013-03-01

This study was performed to determine the effects of sodium bicarbonate injection during prolonged cardiopulmonary resuscitation (for >15 minutes). The retrospective cohort study consisted of adult patients who presented to the emergency department (ED) with the diagnosis of cardiac arrest in 2009. Data were retrieved from the institutional database. A total of 92 patients were enrolled in the study. Patients were divided into 2 groups based on whether they were treated (group1, n = 30) or not treated (group 2, n = 62) with sodium bicarbonate. There were no significant differences in demographic characteristics between groups. The median time interval between the administration of CPR and sodium bicarbonate injection was 36.0 minutes (IQR: 30.5-41.8 minutes). The median amount of bicarbonate injection was 100.2 mEq (IQR: 66.8-104.4). Patients who received a sodium bicarbonate injection during prolonged CPR had a higher percentage of return of spontaneous circulation, but not statistical significant (ROSC, 40.0% vs. 32.3%; P = .465). Sustained ROSC was achieved by 2 (6.7%) patients in the sodium bicarbonate treatment group, with no survival to discharge. No significant differences in vital signs after ROSC were detected between the 2 groups (heart rate, P = .124; systolic blood pressure, P = .094). Sodium bicarbonate injection during prolonged CPR was not associated with ROSC after adjust for variables by regression analysis (Table 3; P = .615; odds ratio, 1.270; 95% confidence interval: 0.501-3.219) The administration of sodium bicarbonate during prolonged CPR did not significantly improve the rate of ROSC in out-of-hospital cardiac arrest. Copyright © 2013 Elsevier Inc. All rights reserved.

Description of quantum coherence in thermodynamic processes requires constraints beyond free energy

Science.gov (United States)

Lostaglio, Matteo; Jennings, David; Rudolph, Terry

2015-03-01

Recent studies have developed fundamental limitations on nanoscale thermodynamics, in terms of a set of independent free energy relations. Here we show that free energy relations cannot properly describe quantum coherence in thermodynamic processes. By casting time-asymmetry as a quantifiable, fundamental resource of a quantum state, we arrive at an additional, independent set of thermodynamic constraints that naturally extend the existing ones. These asymmetry relations reveal that the traditional Szilárd engine argument does not extend automatically to quantum coherences, but instead only relational coherences in a multipartite scenario can contribute to thermodynamic work. We find that coherence transformations are always irreversible. Our results also reveal additional structural parallels between thermodynamics and the theory of entanglement.

Wavelet coherence analysis: A new approach to distinguish organic and functional tremor types.

Science.gov (United States)

Kramer, G; Van der Stouwe, A M M; Maurits, N M; Tijssen, M A J; Elting, J W J

2018-01-01

To distinguish tremor subtypes using wavelet coherence analysis (WCA). WCA enables to detect variations in coherence and phase difference between two signals over time and might be especially useful in distinguishing functional from organic tremor. In this pilot study, polymyography recordings were studied retrospectively of 26 Parkinsonian (PT), 26 functional (FT), 26 essential (ET), and 20 enhanced physiological (EPT) tremor patients. Per patient one segment of 20 s in duration, in which tremor was present continuously in the same posture, was selected. We studied several coherence and phase related parameters, and analysed all possible muscle combinations of the flexor and extensor muscles of the upper and fore arm. The area under the receiver operating characteristic curve (AUC-ROC) was applied to compare WCA and standard coherence analysis to distinguish tremor subtypes. The percentage of time with significant coherence (PTSC) and the number of periods without significant coherence (NOV) proved the most discriminative parameters. FT could be discriminated from organic (PT, ET, EPT) tremor by high NOV (31.88 vs 21.58, 23.12 and 10.20 respectively) with an AUC-ROC of 0.809, while standard coherence analysis resulted in an AUC-ROC of 0.552. EMG-EMG WCA analysis might provide additional variables to distinguish functional from organic tremor. WCA might prove to be of additional value to discriminate between tremor types. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Coherent x-rays from PEP

International Nuclear Information System (INIS)

Baird, S.; Nuhn, H.-D.; Tatchyn, R.; Winick, H.; Fisher, A.S.; Gallardo, J.C.; Pellegrini, C.

1991-01-01

This paper explores the use of a large-circumference, high-energy, electron-positron collider such as PEP to drive a free-electron laser (FEL), producing high levels of coherent power at short wavelengths. The author consider Self-Amplified Spontaneous Emission (SASE), in which electron bunches with low emittance, high peak current and small energy spread radiate coherently in a single passthrough a long undulator. As the electron beam passes down the undulator, its interaction with the increasingly intense spontaneous radiation causes a bunch density modulation at the optical wavelength, resulting in stimulated emissional growth of coherent power in a single pass. The need for optical-cavity mirrors, which place a lower limit on the wavelength of a conventional FEL oscillator, is avoided. The authors explore various combinations of electron-beam and undulator parameters, as well as special undulator designs and optical klystrons (OK), to reach high average or peak coherent power at wavelengths around 40 angstrom by achieving significant exponential gain or full saturation. Examples are presented for devices that achieve high peak coherent power (up to about 400 MW) with lower average coherent power (about 20 mW) and other devices which produce a few watts of average coherent power

Tomographic reconstruction of melanin structures of optical coherence tomography via the finite-difference time-domain simulation

Science.gov (United States)

Huang, Shi-Hao; Wang, Shiang-Jiu; Tseng, Snow H.

2015-03-01

Optical coherence tomography (OCT) provides high resolution, cross-sectional image of internal microstructure of biological tissue. We use the Finite-Difference Time-Domain method (FDTD) to analyze the data acquired by OCT, which can help us reconstruct the refractive index of the biological tissue. We calculate the refractive index tomography and try to match the simulation with the data acquired by OCT. Specifically, we try to reconstruct the structure of melanin, which has complex refractive indices and is the key component of human pigment system. The results indicate that better reconstruction can be achieved for homogenous sample, whereas the reconstruction is degraded for samples with fine structure or with complex interface. Simulation reconstruction shows structures of the Melanin that may be useful for biomedical optics applications.

Coherent response of a semiconductor microcavity in the strong coupling regime

Science.gov (United States)

Cassabois, G.; Triques, A. L. C.; Ferreira, R.; Delalande, C.; Roussignol, Ph; Bogani, F.

2000-05-01

We have studied the coherent dynamics of a semiconductor microcavity by means of interferometric correlation measurements with subpicosecond time resolution in a backscattering geometry. Evidence is brought of the resolution of a homogeneous polariton line in an inhomogeneously broadened exciton system. Surprisingly, photon-like polaritons exhibit an inhomogeneous dephasing. Moreover, we observe an unexpected stationary coherence up to 8 ps for the lower polariton branch close to resonance. All these experimental results are well reproduced within the framework of a linear dispersion theory assuming a coherent superposition of the reflectivity and resonant Rayleigh scattering signals with a well-defined relative phase.

Risks predicting prolonged hospital discharge boarding in a regional acute care hospital.

Science.gov (United States)

Shaikh, Sajid A; Robinson, Richard D; Cheeti, Radhika; Rath, Shyamanand; Cowden, Chad D; Rosinia, Frank; Zenarosa, Nestor R; Wang, Hao

2018-01-30

Prolonged hospital discharge boarding can impact patient flow resulting in upstream Emergency Department crowding. We aim to determine the risks predicting prolonged hospital discharge boarding and their direct and indirect effects on patient flow. Retrospective review of a single hospital discharge database was conducted. Variables including type of disposition, disposition boarding time, case management consultation, discharge medications prescriptions, severity of illness, and patient homeless status were analyzed in a multivariate logistic regression model. Hospital charges, potential savings of hospital bed hours, and whether detailed discharge instructions provided adequate explanations to patients were also analyzed. A total of 11,527 admissions was entered into final analysis. The median discharge boarding time was approximately 2 h. Adjusted Odds Ratio (AOR) of patients transferring to other hospitals was 7.45 (95% CI 5.35-10.37), to court or law enforcement custody was 2.51 (95% CI 1.84-3.42), and to a skilled nursing facility was 2.48 (95% CI 2.10-2.93). AOR was 0.57 (95% CI 0.47-0.71) if the disposition order was placed during normal office hours (0800-1700). AOR of early case management consultation was 1.52 (95% CI 1.37-1.68) versus 1.73 (95% CI 1.03-2.89) for late consultation. Eighty-eight percent of patients experiencing discharge boarding times within 2 h of disposition expressed positive responses when questioned about the quality of explanations of discharge instructions and follow-up plans based on satisfaction surveys. Similar results (86% positive response) were noted among patients whose discharge boarding times were prolonged (> 2 h, p = 0.44). An average charge of $6/bed/h was noted in all hospital discharges. Maximizing early discharge boarding (≤ 2 h) would have resulted in 16,376 hospital bed hours saved thereby averting $98,256.00 in unnecessary dwell time charges in this study population alone. Type of disposition, case

Phase coherence among the Fourier modes and non-Gaussian characteristics in the Alfvén chaos system

Science.gov (United States)

Nariyuki, Yasuhiro; Sasaki, Makoto; Kasuya, Naohiro; Hada, Tohru; Yagi, Masatoshi

2017-03-01

Non-Gaussian characteristics in time series of the Alfvén chaos system are discussed. The phase coherence index, a measure defined by using the surrogate data method and the structure function, is used to evaluate the phase coherence among the Fourier modes. Through Monte Carlo significance testing, it is found that the phase coherence decays monotonically with increasing dissipative parameter and time scale. By applying the Mori projection operator method assuming the Markov process, a model equation for the time correlation function is derived from the generalized Langevin equation. As opposed to the result of the phase coherence analysis, it is concluded that the difference between the direct numerical simulation and the model equation becomes pronounced as the dissipative parameters are increased. This suggests that, even when the phase coherence index is not significant, the underlying physical system may be a non-Gaussian process.

Measurement of the Retention Time of Different Ophthalmic Formulations with Ultrahigh-Resolution Optical Coherence Tomography.

Science.gov (United States)

Gagliano, Caterina; Papa, Vincenzo; Amato, Roberta; Malaguarnera, Giulia; Avitabile, Teresio

2018-04-01

Purpose/aim of the study: The purpose of this study was to measure the pre-corneal retention time of two marketed formulations (eye drops and eye gel) of a steroid-antibiotic fixed combination (FC) containing 0.1% dexamethasone and 0.3% netilmicin. Pre-corneal retention time was evaluated in 16 healthy subjects using an ultrahigh-resolution anterior segment spectral domain optical coherence tomography (OCT). All subjects randomly received both formulations of the FC (Netildex, SIFI, Italy). Central tear film thickness (CTFT) was measured before instillation (time 0) and then after 1, 10, 20, 30, 40 50, 60 and 120 min. The pre-corneal retention time was calculated by plotting CTFT as a function of time. Differences between time points and groups were analyzed by Student's t-test. CTFT increased significantly after the instillation of the eye gel formulation (p < 0.001). CTFT reached its maximum value 1 min after instillation and returned to baseline after 60 min. No effect on CTFT was observed after the instillation of eye drops. The difference between the two formulations was statistically significant at time 1 min (p < 0.0001), 10 min (p < 0.001) and 20 min (p < 0.01). The FC formulated as eye gel was retained on the ocular surface longer than the corresponding eye drop solution. Consequently, the use of the eye gel might extend the interval between instillations and decrease the frequency of administration.

Bursts of Coherent Synchrotron Radiation in Electron Storage Rings: a Dynamical Model

Energy Technology Data Exchange (ETDEWEB)

Venturini, Marco

2002-09-17

Evidence of coherent synchrotron radiation (CSR) has been reported recently at the electron storage rings of several light source facilities. The main features of the observations are (i) a radiation wavelength short compared to the nominal bunch length, and (ii) a coherent signal showing recurrent bursts of duration much shorter than the radiation damping time, but with spacing equal to a substantial fraction of the damping time. We present a model of beam longitudinal dynamics that reproduces these features.

Geometric and dynamic perspectives on phase-coherent and noncoherent chaos.

Science.gov (United States)

Zou, Yong; Donner, Reik V; Kurths, Jürgen

2012-03-01

Statistically distinguishing between phase-coherent and noncoherent chaotic dynamics from time series is a contemporary problem in nonlinear sciences. In this work, we propose different measures based on recurrence properties of recorded trajectories, which characterize the underlying systems from both geometric and dynamic viewpoints. The potentials of the individual measures for discriminating phase-coherent and noncoherent chaotic oscillations are discussed. A detailed numerical analysis is performed for the chaotic Rössler system, which displays both types of chaos as one control parameter is varied, and the Mackey-Glass system as an example of a time-delay system with noncoherent chaos. Our results demonstrate that especially geometric measures from recurrence network analysis are well suited for tracing transitions between spiral- and screw-type chaos, a common route from phase-coherent to noncoherent chaos also found in other nonlinear oscillators. A detailed explanation of the observed behavior in terms of attractor geometry is given.

Prolonged ultraviolet light-induced erythema and the cutaneous carcinoma phenotype

International Nuclear Information System (INIS)

Tanenbaum, L.; Parrish, J.A.; Haynes, H.A.; Fitzpatrick, T.B.; Pathak, M.A.

1976-01-01

A considerable amount of evidence exists in support of the role of ultraviolet radiation as a major etiologic factor in human skin cancer, both melanoma and carcinoma types. On the basis of epidemiologic studies a phenotype has been described which helps to identify the persons who are more susceptible to skin cancer. In an attempt to further define this population, patients with cutaneous carcinoma and a normal control group were exposed to artificial ultraviolet light (UVL) and the erythema and tanning responses of each group were measured over a 21-day period. UVL-induced erythema was prolonged in a significantly higher percentage of patients with skin cancer than in control patients, lasting two to three weeks after single exposures to 6 and 8 times the patient's minimal erythema dose. The presence of prolonged erythema correlated with this history of previous skin cancer but did not correlate with other established risk factors for cutaneous carcinoma, i.e., fair skin, light hair and light eyes, easy sunburning and poor tanning, and Celtic ancestry. Prolonged erythema following UVL radiation may therefore represent an additional risk factor and help to identify the skin cancer-susceptible population

Subpicosecond Coherent Manipulation of X-Rays

International Nuclear Information System (INIS)

Adams, Bernhard W.

2004-01-01

The Takagi-Taupin theory is synthesized with the eikonal theory in a unified space-time approach, based upon microscopic electromagnetism. It is designed specifically to address x-ray diffraction in crystal structures being modified within down to a few femtosconds. Possible applications in the subpicosecond coherent manipulation of x-rays are given

Fluctuation theorems in feedback-controlled open quantum systems: Quantum coherence and absolute irreversibility

Science.gov (United States)

Murashita, Yûto; Gong, Zongping; Ashida, Yuto; Ueda, Masahito

2017-10-01

The thermodynamics of quantum coherence has attracted growing attention recently, where the thermodynamic advantage of quantum superposition is characterized in terms of quantum thermodynamics. We investigate the thermodynamic effects of quantum coherent driving in the context of the fluctuation theorem. We adopt a quantum-trajectory approach to investigate open quantum systems under feedback control. In these systems, the measurement backaction in the forward process plays a key role, and therefore the corresponding time-reversed quantum measurement and postselection must be considered in the backward process, in sharp contrast to the classical case. The state reduction associated with quantum measurement, in general, creates a zero-probability region in the space of quantum trajectories of the forward process, which causes singularly strong irreversibility with divergent entropy production (i.e., absolute irreversibility) and hence makes the ordinary fluctuation theorem break down. In the classical case, the error-free measurement ordinarily leads to absolute irreversibility, because the measurement restricts classical paths to the region compatible with the measurement outcome. In contrast, in open quantum systems, absolute irreversibility is suppressed even in the presence of the projective measurement due to those quantum rare events that go through the classically forbidden region with the aid of quantum coherent driving. This suppression of absolute irreversibility exemplifies the thermodynamic advantage of quantum coherent driving. Absolute irreversibility is shown to emerge in the absence of coherent driving after the measurement, especially in systems under time-delayed feedback control. We show that absolute irreversibility is mitigated by increasing the duration of quantum coherent driving or decreasing the delay time of feedback control.

Prolonged QRS Widening After Aripiprazole Overdose.

Science.gov (United States)

Mazer-Amirshahi, Maryann; Porter, Robert; Dewey, Kayla

2018-05-05

Aripiprazole is an atypical antipsychotic with a long half-life. Overdose can result in protracted somnolence and cardiac disturbances, particularly QT interval prolongation. This is a single case report of a 14-year-old boy who took an overdose of aripiprazole and developed QRS widening. A 14-year-old boy intentionally ingested 20 tablets of aripiprazole (5 mg). He was brought to the emergency department when his ingestion was discovered. The patient's vital signs were as follows: temperature, 37.7°C; heart rate, 108 beats/min; blood pressure, 138/98 mm Hg; and respirations, 16 breaths/min. Activated charcoal was administered within 90 minutes of ingestion. Initial electrocardiogram (EKG) showed sinus tachycardia, with a QRS of 138 ms and QT interval of 444 ms. QRS duration was 90 ms on an EKG performed 3 months earlier. A bolus of sodium bicarbonate was administered, and the patient was transferred to the pediatric intensive care unit. Repeat EKG demonstrated a QRS of 156 ms, and a sodium bicarbonate infusion was initiated. The patient continued to have QRS prolongation for the next 8 days, reaching a peak of 172 ms 3 days postingestion. Despite aggressive treatment with sodium bicarbonate, there was persistent QRS prolongation; however, the patient did not have any dysrhythmias and remained hemodynamically stable. The patient was discharged 9 days postingestion when the QRS duration normalized to 82 ms. Genetic testing revealed that the patient was a CYP2D6 poor metabolizer. This case suggests that aripiprazole toxicity may possibly be associated with QRS prolongation without associated dysrhythmias or cardiovascular compromise. In addition, toxicity may be prolonged in patients who are CYP2D6 poor metabolizers.

Cell response to quasi-monochromatic light with different coherence

Energy Technology Data Exchange (ETDEWEB)

Budagovsky, A V; Solovykh, N V [I.V.Michurin All-Russian Recearch Institute of Fruit Crops Genetics and Breeding (Russian Federation); Budagovskaya, O N [I.V.Michurin All-Russia Research and Development Institute of Gardening, Michurinsk, Tambov region (Russian Federation); Budagovsky, I A [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2015-04-30

The problem of the light coherence effect on the magnitude of the photoinduced cell response is discussed. The origins of ambiguous interpretation of the known experimental results are considered. Using the biological models, essentially differing in anatomy, morphology and biological functions (acrospires of radish, blackberry microsprouts cultivated in vitro, plum pollen), the effect of statistical properties of quasi-monochromatic light (λ{sub max} = 633 nm) on the magnitude of the photoinduced cell response is shown. It is found that for relatively low spatial coherence, the cell functional activity changes insignificantly. The maximal enhancement of growing processes (stimulating effect) is observed when the coherence length L{sub coh} and the correlation radius r{sub cor} are greater than the cell size, i.e., the entire cell fits into the field coherence volume. In this case, the representative indicators (germination of seeds and pollen, the spears length) exceeds those of non-irradiated objects by 1.7 – 3.9 times. For more correct assessment of the effect of light statistical properties on photocontrol processes, it is proposed to replace the qualitative description (coherent – incoherent) with the quantitative one, using the determination of spatial and temporal correlation functions and comparing them with the characteristic dimensions of the biological structures, e.g., the cell size. (biophotonics)

Qubit lattice coherence induced by electromagnetic pulses in superconducting metamaterials.

Science.gov (United States)

Ivić, Z; Lazarides, N; Tsironis, G P

2016-07-12

Quantum bits (qubits) are at the heart of quantum information processing schemes. Currently, solid-state qubits, and in particular the superconducting ones, seem to satisfy the requirements for being the building blocks of viable quantum computers, since they exhibit relatively long coherence times, extremely low dissipation, and scalability. The possibility of achieving quantum coherence in macroscopic circuits comprising Josephson junctions, envisioned by Legett in the 1980's, was demonstrated for the first time in a charge qubit; since then, the exploitation of macroscopic quantum effects in low-capacitance Josephson junction circuits allowed for the realization of several kinds of superconducting qubits. Furthermore, coupling between qubits has been successfully achieved that was followed by the construction of multiple-qubit logic gates and the implementation of several algorithms. Here it is demonstrated that induced qubit lattice coherence as well as two remarkable quantum coherent optical phenomena, i.e., self-induced transparency and Dicke-type superradiance, may occur during light-pulse propagation in quantum metamaterials comprising superconducting charge qubits. The generated qubit lattice pulse forms a compound "quantum breather" that propagates in synchrony with the electromagnetic pulse. The experimental confirmation of such effects in superconducting quantum metamaterials may open a new pathway to potentially powerful quantum computing.

Optical technologies for extreme-ultraviolet and soft X-ray coherent sources

International Nuclear Information System (INIS)

Canova, Federico; Poletto, Luca

2015-01-01

The book reviews the most recent achievements in optical technologies for XUV and X-ray coherent sources. Particular attention is given to free-electron-laser facilities, but also to other sources available at present, such as synchrotrons, high-order laser harmonics and X-ray lasers. The optical technologies relevant to each type of source are discussed. In addition, the main technologies used for photon handling and conditioning, namely multilayer mirrors, adaptive optics, crystals and gratings are explained. Experiments using coherent light received during the last decades a lot of attention for the X-ray regime. Strong efforts were taken for the realization of almost fully coherent sources, e.g. the free-electron lasers, both as independent sources in the femtosecond and attosecond regimes and as seeding sources for free-electron-lasers and X-ray gas lasers. In parallel to the development of sources, optical technologies for photon handling and conditioning of such coherent and intense X-ray beams advanced. New problems were faced for the realization of optical components of beamlines demanding to manage coherent X-ray photons, e.g. the preservation of coherence and time structure of ultra short pulses.

The COHERENT Experiment at the Spallation Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Elliott, Steven Ray [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

2015-09-30

The COHERENT collaboration's primary objective is to measure coherent elastic neutrino- nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. The CEvNS cross section is cleanly predicted in the standard model; hence its measurement provides a standard model test. It is relevant for supernova physics and supernova-neutrino detection, and enables validation of dark-matter detector background and detector-response models. In the long term, precision measurement of CEvNS will address questions of nuclear structure. COHERENT will deploy multiple detector technologies in a phased approach: a 14-kg CsI[Na] scintillating crystal, 15 kg of p-type point-contact germanium detectors, and 100 kg of liquid xenon in a two-phase time projection chamber. Following an extensive background measurement campaign, a location in the SNS basement has proven to be neutron-quiet and suitable for deployment of the COHERENT detector suite. The simultaneous deployment of the three COHERENT detector subsystems will test the N=2 dependence of the cross section and ensure an unambiguous discovery of CEvNS. This document describes concisely the COHERENT physics motivations, sensitivity and plans for measurements at the SNS to be accomplished on a four-year timescale.

Source coherence impairments in a direct detection direct sequence optical code-division multiple-access system.

Science.gov (United States)

Fsaifes, Ihsan; Lepers, Catherine; Lourdiane, Mounia; Gallion, Philippe; Beugin, Vincent; Guignard, Philippe

2007-02-01

We demonstrate that direct sequence optical code- division multiple-access (DS-OCDMA) encoders and decoders using sampled fiber Bragg gratings (S-FBGs) behave as multipath interferometers. In that case, chip pulses of the prime sequence codes generated by spreading in time-coherent data pulses can result from multiple reflections in the interferometers that can superimpose within a chip time duration. We show that the autocorrelation function has to be considered as the sum of complex amplitudes of the combined chip as the laser source coherence time is much greater than the integration time of the photodetector. To reduce the sensitivity of the DS-OCDMA system to the coherence time of the laser source, we analyze the use of sparse and nonperiodic quadratic congruence and extended quadratic congruence codes.

Source coherence impairments in a direct detection direct sequence optical code-division multiple-access system

Science.gov (United States)

Fsaifes, Ihsan; Lepers, Catherine; Lourdiane, Mounia; Gallion, Philippe; Beugin, Vincent; Guignard, Philippe

2007-02-01

We demonstrate that direct sequence optical code- division multiple-access (DS-OCDMA) encoders and decoders using sampled fiber Bragg gratings (S-FBGs) behave as multipath interferometers. In that case, chip pulses of the prime sequence codes generated by spreading in time-coherent data pulses can result from multiple reflections in the interferometers that can superimpose within a chip time duration. We show that the autocorrelation function has to be considered as the sum of complex amplitudes of the combined chip as the laser source coherence time is much greater than the integration time of the photodetector. To reduce the sensitivity of the DS-OCDMA system to the coherence time of the laser source, we analyze the use of sparse and nonperiodic quadratic congruence and extended quadratic congruence codes.

Coherence and Sense of Coherence

DEFF Research Database (Denmark)

Dau, Susanne

2014-01-01

Constraints in the implementation of models of blended learning can be explained by several causes, but in this paper, it is illustrated that lack of sense of coherence is a major factor of these constraints along with the referential whole of the perceived learning environments. The question exa...

Coherent states and rational surfaces

International Nuclear Information System (INIS)

Brody, Dorje C; Graefe, Eva-Maria

2010-01-01

The state spaces of generalized coherent states associated with special unitary groups are shown to form rational curves and surfaces in the space of pure states. These curves and surfaces are generated by the various Veronese embeddings of the underlying state space into higher dimensional state spaces. This construction is applied to the parameterization of generalized coherent states, which is useful for practical calculations, and provides an elementary combinatorial approach to the geometry of the coherent state space. The results are extended to Hilbert spaces with indefinite inner products, leading to the introduction of a new kind of generalized coherent states.

Prolonging the viability of Lactobacillus plantarum through the addition of prebiotics into the medium.

Science.gov (United States)

Altieri, Clelia; Bevilacqua, Antonio; Sinigaglia, Milena

2011-08-01

This article reports on the effects of prebiotics on the growth/death kinetics, metabolism, and biomass production by 2 strains of Lactobacillus plantarum (c19 and DSMZ 2601, isolated from table olives and purchased from a Public Collection, respectively). The research was divided into 3 different steps, in order to highlight the optimal combination for cell viability and experiments were performed under the conditions of an accelerated shelf life test; thus, 3 combinations were pointed out (fructooligosaccharides [FOS], 5 g/L; glucose + inulin, 2.5 + 2.5 g/L; glucose + FOS, 2.5 + 2.5 g/L). A sample containing only glucose was used as control. The results highlighted that the 3 combinations aforementioned prolonged cell viability over the time both under low and high inoculum conditions (3 and 9 log CFU/mL, respectively); however, FOS alone caused a reduction of biomass production, even if cell number was not affected by this compound. Therefore, as a final result of this research, the combination glucose + FOS could be proposed as a suitable mean to achieve an optimal production of biomass and prolong cell viability over the time. Food producers require a prolonged viability of probiotic bacteria in functional foods; this goal is usually achieved by refrigeration. In this article, the prolongation of cell viability through the addition of prebiotics was proposed. © 2011 Institute of Food Technologists®

Selective Coherent Excitation of Charged Density Waves

NARCIS (Netherlands)

Tsvetkov, A.A.; Sagar, D.M.; Loosdrecht, P.H.M. van; Marel, D. van der

2003-01-01

Real time femtosecond pump-probe spectroscopy is used to study collective and single particle excitations in the charge density wave state of the quasi-1D metal, blue bronze. Along with the previously observed collective amplitudon excitation, the spectra show several additional coherent features.

Fractal approach towards power-law coherency to measure cross-correlations between time series

Czech Academy of Sciences Publication Activity Database

Krištoufek, Ladislav

2017-01-01

Roč. 50, č. 1 (2017), s. 193-200 ISSN 1007-5704 R&D Projects: GA ČR(CZ) GP14-11402P Institutional support: RVO:67985556 Keywords : power- law coherency * power- law cross-correlations * correlations Subject RIV: AH - Economics OBOR OECD: Applied Economics, Econometrics Impact factor: 2.784, year: 2016 http://library.utia.cas.cz/separaty/2017/E/kristoufek-0473066.pdf

Higher coherent x-ray laser

International Nuclear Information System (INIS)

Hasegawa, Noboru; Nagashima, Keisuke; Kawachi, Tetsuya

2001-01-01

X-ray lasers generated by an ultra short pulse laser have advantages such as monochromatic, short pulse duration, small beam divergence, high intensity, and coherence. Spatial coherence is most important for applications, we have investigated the transient collisional excitation (TCE) scheme x-ray laser lasing from Ne-like titanium (31.6 nm), Ne-like silver (13.9 nm) and tin (11.9 nm). However, the spatial coherence was not so good with this scheme. We have been studying to improve the spatial coherence of the x-ray laser and have proposed to use coherent seed light tuned to the x-ray laser wavelength generated from higher harmonics generation (HHG), which is introduced to the x-ray laser medium (Ne-like titanium, Ni-like silver plasmas). We present about the theoretical study of the coupling efficiency HHG light with x-ray laser medium. (author)

Handbook of coherent domain optical methods biomedical diagnostics, environmental and material science

CERN Document Server

2004-01-01

For the first time in one set of books, coherent-domain optical methods are discussed in the framework of various applications, which are characterized by a strong light scattering. A few chapters describe basic research containing the updated results on coherent and polarized light non-destructive interactions with a scattering medium, in particular, diffraction, interference, and speckle formation at multiple scattering. These chapters allow for understanding coherent-domain diagnostic techniques presented in later chapters. A large portion of Volume I is dedicated to analysis of various aspects of optical coherence tomography (OCT) - a very new and growing field of coherent optics. Two chapters on laser scanning confocal microscopy give insight to recent extraordinary results on in vivo imaging and compare the possibilities and achievements of confocol, excitation multiphoton, and OCT microscopy. This two volume reference contains descriptions of holography, interferometry and optical heterodyning techniqu...

Optical coherence tomography in conjunction with bronchoscopy

International Nuclear Information System (INIS)

Rodrigues, Ascedio Jose; Takimura, Celso Kiyochi; Lemos Neto, Pedro Alves; Figueiredo, Viviane Rossi

2012-01-01

To evaluate the feasibility of and the potential for using optical coherence tomography in conjunction with conventional bronchoscopy in the evaluation of the airways. Methods: This was a pilot study based on an ex vivo experimental model involving three animals: one adult New Zealand rabbit and two Landrace pigs. An optical coherence tomography imaging catheter was inserted through the working channel of a flexible bronchoscope in order to reach the distal trachea of the animals. Images of the walls of the trachea were systematically taken along its entire length, from the distal to the proximal portion. Results: The imaging catheter was easily adapted to the working channel of the bronchoscope. High-resolution images of cross sections of the trachea were taken in real time, precisely delineating microstructures, such as the epithelium, submucosa, and cartilage, as well as the adventitia of the anterior and lateral tracheal walls. The corresponding layers of the epithelium, mucosa, and cartilage were clearly differentiated. The mucosa, submucosa, and trachealis muscle were clearly identified in the posterior wall. Conclusions: It is feasible to use an optical coherence tomography imaging catheter in combination with a flexible bronchoscope. Optical coherence tomography produces high resolution images that reveal the microanatomy of the trachea, including structures that are typically seen only on images produced by conventional histology. (author)

Optical coherence tomography in conjunction with bronchoscopy

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Ascedio Jose; Takimura, Celso Kiyochi; Lemos Neto, Pedro Alves; Figueiredo, Viviane Rossi, E-mail: ascedio@gmail.com [Servico de Endoscopia Respiratoria, Hospital das Clinicas, Universidade de Sao Paulo (FM/USP), SP (Brazil)

2012-07-01

To evaluate the feasibility of and the potential for using optical coherence tomography in conjunction with conventional bronchoscopy in the evaluation of the airways. Methods: This was a pilot study based on an ex vivo experimental model involving three animals: one adult New Zealand rabbit and two Landrace pigs. An optical coherence tomography imaging catheter was inserted through the working channel of a flexible bronchoscope in order to reach the distal trachea of the animals. Images of the walls of the trachea were systematically taken along its entire length, from the distal to the proximal portion. Results: The imaging catheter was easily adapted to the working channel of the bronchoscope. High-resolution images of cross sections of the trachea were taken in real time, precisely delineating microstructures, such as the epithelium, submucosa, and cartilage, as well as the adventitia of the anterior and lateral tracheal walls. The corresponding layers of the epithelium, mucosa, and cartilage were clearly differentiated. The mucosa, submucosa, and trachealis muscle were clearly identified in the posterior wall. Conclusions: It is feasible to use an optical coherence tomography imaging catheter in combination with a flexible bronchoscope. Optical coherence tomography produces high resolution images that reveal the microanatomy of the trachea, including structures that are typically seen only on images produced by conventional histology. (author)

Parametric imaging of viscoelasticity using optical coherence elastography

Science.gov (United States)

Wijesinghe, Philip; McLaughlin, Robert A.; Sampson, David D.; Kennedy, Brendan F.

2015-03-01

We demonstrate imaging of soft tissue viscoelasticity using optical coherence elastography. Viscoelastic creep deformation is induced in tissue using step-like compressive loading and the resulting time-varying deformation is measured using phase-sensitive optical coherence tomography. From a series of co-located B-scans, we estimate the local strain rate as a function of time, and parameterize it using a four-parameter Kelvin-Voigt model of viscoelastic creep. The estimated viscoelastic strain and time constant are used to visualize viscoelastic creep in 2D, dual-parameter viscoelastograms. We demonstrate our technique on six silicone tissue-simulating phantoms spanning a range of viscoelastic parameters. As an example in soft tissue, we report viscoelastic contrast between muscle and connective tissue in fresh, ex vivo rat gastrocnemius muscle and mouse abdominal transection. Imaging viscoelastic creep deformation has the potential to provide complementary contrast to existing imaging modalities, and may provide greater insight into disease pathology.

Effect of prolonged isothermal heat treatment on the mechanical behavior of advanced NANOBAIN steel

Science.gov (United States)

Avishan, Behzad

2017-09-01

The microstructural evolution and consequent changes in strength and ductility of advanced NANOBAIN steel during prolonged isothermal heat-treatment stages were investigated. The microstructure and mechanical properties of nanostructured bainite were not expected to be influenced by extending the heat-treatment time beyond the optimum value because of the autotempering phenomenon and high tempering resistance. However, experimental results indicated that the microstructure was thermodynamically unstable and that prolonged austempering resulted in carbon depletion from high-carbon retained austenite and carbide precipitations. Therefore, austenite became thermally less stable and partially transformed into martensite during cooling to room temperature. Prolonged austempering did not lead to the typical tempering sequence of bainite, and the sizes of the microstructural constituents were independent of the extended heat-treatment times. This independence, in turn, resulted in almost constant ultimate tensile strength values. However, microstructural variations enhanced the yield strength and the hardness of the material at extended isothermal heat-treatment stages. Finally, although microstructural changes decreased the total elongation and impact toughness, considerable combinations of mechanical properties could still be achieved.

Gain with and without population inversion via vacuum-induced coherence in a V-type atom without external coherent driving

International Nuclear Information System (INIS)

Xu Weihua; Wu Jinhui; Gao Jinyue

2006-01-01

In a three-level V-type atomic system without any external coherent driving, owing to the coherence that results from the vacuum of the radiation field, both the probe gain with and without population inversion can be achieved with very weak incoherent pumping. The gain is achieved in the absence of any external coherent driving field, so it is different from the gain without inversion in ordinary laser-driven schemes where a coherent driving field is necessary to create the coherence. The gain is also different from the conventional lasing gain because the population inversion is achieved via vacuum-induced coherence, which is dependent on the atomic coherence

Lagrangian motion, coherent structures, and lines of persistent material strain.

Science.gov (United States)

Samelson, R M

2013-01-01

Lagrangian motion in geophysical fluids may be strongly influenced by coherent structures that support distinct regimes in a given flow. The problems of identifying and demarcating Lagrangian regime boundaries associated with dynamical coherent structures in a given velocity field can be studied using approaches originally developed in the context of the abstract geometric theory of ordinary differential equations. An essential insight is that when coherent structures exist in a flow, Lagrangian regime boundaries may often be indicated as material curves on which the Lagrangian-mean principal-axis strain is large. This insight is the foundation of many numerical techniques for identifying such features in complex observed or numerically simulated ocean flows. The basic theoretical ideas are illustrated with a simple, kinematic traveling-wave model. The corresponding numerical algorithms for identifying candidate Lagrangian regime boundaries and lines of principal Lagrangian strain (also called Lagrangian coherent structures) are divided into parcel and bundle schemes; the latter include the finite-time and finite-size Lyapunov exponent/Lagrangian strain (FTLE/FTLS and FSLE/FSLS) metrics. Some aspects and results of oceanographic studies based on these approaches are reviewed, and the results are discussed in the context of oceanographic observations of dynamical coherent structures.

Coherent Smith-Purcell radiation: Theories and simulations

International Nuclear Information System (INIS)

Donohue, J.T.; Gardelle, J.

2008-01-01

Smith-Purcell (SP) radiation has been observed many times over the past fifty years, and several theories have been proposed to explain it. However, it is only quite recently that Andrews, Brau and collaborators made a considerable advance in understanding how coherent SP radiation may be produced from an initially continuous beam. Their work received support from 2-D simulations which were performed using the Particle-in-Cell (PIC) code 'MAGIC'. Here we present a review of our 2-D simulations of coherent SP and discuss how they relate to the model of Andrews and Brau. We also describe briefly a SP experiment in the microwave domain using a sheet beam that is planned for 2008

Coherent spin-rotational dynamics of oxygen superrotors

Science.gov (United States)

Milner, Alexander A.; Korobenko, Aleksey; Milner, Valery

2014-09-01

We use state- and time-resolved coherent Raman spectroscopy to study the rotational dynamics of oxygen molecules in ultra-high rotational states. While it is possible to reach rotational quantum numbers up to N≈ 50 by increasing the gas temperature to 1500 K, low population levels and gas densities result in correspondingly weak optical response. By spinning {{O}2} molecules with an optical centrifuge, we efficiently excite extreme rotational states with N≤slant 109 in high-density room temperature ensembles. Fast molecular rotation results in the enhanced robustness of the created rotational wave packets against collisions, enabling us to observe the effects of weak spin-rotation coupling in the coherent rotational dynamics of oxygen. The decay rate of spin-rotational coherence due to collisions is measured as a function of the molecular angular momentum and its dependence on the collisional adiabaticity parameter is discussed. We find that at high values of N, the rotational decoherence of oxygen is much faster than that of the previously studied non-magnetic nitrogen molecules, pointing at the effects of spin relaxation in paramagnetic gases.

VCSEL Based Coherent PONs

DEFF Research Database (Denmark)

Jensen, Jesper Bevensee; Rodes, Roberto; Caballero Jambrina, Antonio

2014-01-01

We present a review of research performed in the area of coherent access technologies employing vertical cavity surface emitting lasers (VCSELs). Experimental demonstrations of optical transmission over a passive fiber link with coherent detection using VCSEL local oscillators and directly modula...

Description of quantum coherence in thermodynamic processes requires constraints beyond free energy

Science.gov (United States)

Lostaglio, Matteo; Jennings, David; Rudolph, Terry

2015-01-01

Recent studies have developed fundamental limitations on nanoscale thermodynamics, in terms of a set of independent free energy relations. Here we show that free energy relations cannot properly describe quantum coherence in thermodynamic processes. By casting time-asymmetry as a quantifiable, fundamental resource of a quantum state, we arrive at an additional, independent set of thermodynamic constraints that naturally extend the existing ones. These asymmetry relations reveal that the traditional Szilárd engine argument does not extend automatically to quantum coherences, but instead only relational coherences in a multipartite scenario can contribute to thermodynamic work. We find that coherence transformations are always irreversible. Our results also reveal additional structural parallels between thermodynamics and the theory of entanglement. PMID:25754774

Nonlinear Coherent Structures, Microbursts and Turbulence

Science.gov (United States)

Lakhina, G. S.

2015-12-01

Nonlinear waves are found everywhere, in fluids, atmosphere, laboratory, space and astrophysical plasmas. The interplay of nonlinear effects, dispersion and dissipation in the medium can lead to a variety of nonlinear waves and turbulence. Two cases of coherent nonlinear waves: chorus and electrostatic solitary waves (ESWs) and their impact on modifying the plasma medium are discussed. Chorus is a right-hand, circularly-polarized electromagnetic plane wave. Dayside chorus is a bursty emission composed of rising frequency "elements" with duration of ~0.1 to 1.0 s. Each element is composed of coherent subelements with durations of ~1 to 100 ms or more. The cyclotron resonant interaction between energetic electrons and the coherent chorus waves is studied. An expression for the pitch angle transport due to this interaction is derived considering a Gaussian distribution for the time duration of the chorus elements. The rapid pitch scattering can provide an explanation for the ionospheric microbursts of ~0.1 to 0.5 s in bremsstrahlung x-rays formed by ~10-100 keV precipitating electrons. On the other hand, the ESWs are observed in the electric field component parallel to the background magnetic field, and are usually bipolar or tripolar. Generation of coherent ESWs has been explained in terms of nonlinear fluid models of ion- and electron-acoustic solitons and double layers (DLs) based on Sagdeev pseudopotential technique. Fast Fourier transform of electron- and ion-acoustic solitons/DLs produces broadband wave spectra which can explain the properties of the electrostatic turbulence observed in the magnetosheath and plasma sheet boundary layer, and in the solar wind, respectively.

Coherent storage of temporally multimode light using a spin-wave atomic frequency comb memory

International Nuclear Information System (INIS)

Gündoğan, M; Mazzera, M; Ledingham, P M; Cristiani, M; De Riedmatten, H

2013-01-01

We report on the coherent and multi-temporal mode storage of light using the full atomic frequency comb memory scheme. The scheme involves the transfer of optical atomic excitations in Pr 3+ :Y 2 SiO 5 to spin waves in hyperfine levels using strong single-frequency transfer pulses. Using this scheme, a total of five temporal modes are stored and recalled on-demand from the memory. The coherence of the storage and retrieval is characterized using a time-bin interference measurement resulting in visibilities higher than 80%, independent of the storage time. This coherent and multimode spin-wave memory is promising as a quantum memory for light. (paper)

Signatures of discrete breathers in coherent state quantum dynamics

International Nuclear Information System (INIS)

Igumenshchev, Kirill; Ovchinnikov, Misha; Prezhdo, Oleg; Maniadis, Panagiotis

2013-01-01

In classical mechanics, discrete breathers (DBs) – a spatial time-periodic localization of energy – are predicted in a large variety of nonlinear systems. Motivated by a conceptual bridging of the DB phenomena in classical and quantum mechanical representations, we study their signatures in the dynamics of a quantum equivalent of a classical mechanical point in phase space – a coherent state. In contrast to the classical point that exhibits either delocalized or localized motion, the coherent state shows signatures of both localized and delocalized behavior. The transition from normal to local modes have different characteristics in quantum and classical perspectives. Here, we get an insight into the connection between classical and quantum perspectives by analyzing the decomposition of the coherent state into system's eigenstates, and analyzing the spacial distribution of the wave-function density within these eigenstates. We find that the delocalized and localized eigenvalue components of the coherent state are separated by a mixed region, where both kinds of behavior can be observed. Further analysis leads to the following observations. Considered as a function of coupling, energy eigenstates go through avoided crossings between tunneling and non-tunneling modes. The dominance of tunneling modes in the high nonlinearity region is compromised by the appearance of new types of modes – high order tunneling modes – that are similar to the tunneling modes but have attributes of non-tunneling modes. Certain types of excitations preferentially excite higher order tunneling modes, allowing one to study their properties. Since auto-correlation functions decrease quickly in highly nonlinear systems, short-time dynamics are sufficient for modeling quantum DBs. This work provides a foundation for implementing modern semi-classical methods to model quantum DBs, bridging classical and quantum mechanical signatures of DBs, and understanding spectroscopic experiments

Telescope aperture optimization for spacebased coherent wind lidar

Science.gov (United States)

Ge, Xian-ying; Zhu, Jun; Cao, Qipeng; Zhang, Yinchao; Yin, Huan; Dong, Xiaojing; Wang, Chao; Zhang, Yongchao; Zhang, Ning

2015-08-01

Many studies have indicated that the optimum measurement approach for winds from space is a pulsed coherent wind lidar, which is an active remote sensing tool with the characteristics that high spatial and temporal resolutions, real-time detection, high mobility, facilitated control and so on. Because of the significant eye safety, efficiency, size, and lifetime advantage, 2μm wavelength solid-state laser lidar systems have attracted much attention in spacebased wind lidar plans. In this paper, the theory of coherent detection is presented and a 2μm wavelength solid-state laser lidar system is introduced, then the ideal aperture is calculated from signal-to-noise(SNR) view at orbit 400km. However, considering real application, even if the lidar hardware is perfectly aligned, the directional jitter of laser beam, the attitude change of the lidar in the long round trip time of the light from the atmosphere and other factors can bring misalignment angle. So the influence of misalignment angle is considered and calculated, and the optimum telescope diameter(0.45m) is obtained as the misalignment angle is 4 μrad. By the analysis of the optimum aperture required for spacebased coherent wind lidar system, we try to present the design guidance for the telescope.

Multi-channel coherent perfect absorbers

KAUST Repository

Bai, Ping

2016-05-18

The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

Multi-channel coherent perfect absorbers

KAUST Repository

Bai, Ping; Wu, Ying; Lai, Yun

2016-01-01

The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

Coherent Multistatic ISAR Imaging

NARCIS (Netherlands)

Dorp, Ph. van; Otten, M.P.G.; Verzeilberg, J.M.M.

2012-01-01

This paper presents methods for Coherent Multistatic Radar Imaging for Non Cooperative Target Recognition (NCTR) with a network of radar sensors. Coherent Multistatic Radar Imaging is based on an extension of existing monostatic ISAR algorithms to the multistatic environment. The paper describes the

Coherence and correspondence in engineering design

Directory of Open Access Journals (Sweden)

Konstantinos V. Katsikopoulos

2009-03-01

Full Text Available I show how the coherence/correspondence distinction can inform the conversation about decision methods for engineering design. Some engineers argue for the application of multi-attribute utility theory while others argue for what they call heuristics. To clarify the differences among methods, I first ask whether each method aims at achieving coherence or correspondence. By analyzing statements in the design literature, I argue that utility theory aims at achieving coherence and heuristics aim at achieving correspondence. Second, I ask if achieving coherence always implies achieving correspondence. It is important to provide an answer because while in design the objective is correspondence, it is difficult to assess it, and coherence that is easier to assess is used as a surrogate. I argue that coherence does not always imply correspondence in design and that this is also the case in problems studied in judgment and decision-making research. Uncovering the conditions under which coherence implies, or does not imply, correspondence is a topic where engineering design and judgment and decision-making research might connect.

Maintaining Web Cache Coherency

Directory of Open Access Journals (Sweden)

2000-01-01

Full Text Available Document coherency is a challenging problem for Web caching. Once the documents are cached throughout the Internet, it is often difficult to keep them coherent with the origin document without generating a new traffic that could increase the traffic on the international backbone and overload the popular servers. Several solutions have been proposed to solve this problem, among them two categories have been widely discussed: the strong document coherency and the weak document coherency. The cost and the efficiency of the two categories are still a controversial issue, while in some studies the strong coherency is far too expensive to be used in the Web context, in other studies it could be maintained at a low cost. The accuracy of these analysis is depending very much on how the document updating process is approximated. In this study, we compare some of the coherence methods proposed for Web caching. Among other points, we study the side effects of these methods on the Internet traffic. The ultimate goal is to study the cache behavior under several conditions, which will cover some of the factors that play an important role in the Web cache performance evaluation and quantify their impact on the simulation accuracy. The results presented in this study show indeed some differences in the outcome of the simulation of a Web cache depending on the workload being used, and the probability distribution used to approximate updates on the cached documents. Each experiment shows two case studies that outline the impact of the considered parameter on the performance of the cache.

Nuclear energy as a 'golden bridge'? Constitutional legal problems of the negotiation of the prolongation of the running time against skimming of profits; Kernenergie als 'goldene Bruecke'? Verfassungsrechtliche Probleme der Aushandlung von Laufzeitverlaengerungen gegen Gewinnabschoepfungen

Energy Technology Data Exchange (ETDEWEB)

Waldhoff, Christian; Aswege, Hanka von [Bonn Univ. (Germany). Lehrstuhl fuer Oeffentliches Recht

2010-07-15

The coalition agreement of Christian Demographic Union (CDU), Christian Social Union (CSU) and Free Democratic Party (FDP) from 26th October, 2009 characterizes the nuclear energy as a bridge technology. The coalition parties explain to prolong the running times of German nuclear power stations up to a reliable replacement by renewable energies. The conditions for the prolongation of the running times are to be regulated in agreement with energy supply companies. In the contribution under consideration, the authors report on the fiscal legal problems of the skimming of profits. Constitutional legal problems of the earmaking of a skimming of profits as well as a consensual agreement are discussed in this contribution. In the result, a financial constitutionally reliable way for the skimming of added profits due to prolongation of the running time is not evident. The legal earmaking of the duty advent for the promotion of renewable energies increases the constitutional doubts.

Optimization of a coherent soft x-ray beamline for coherent scattering experiments at NSLS-II

Energy Technology Data Exchange (ETDEWEB)

Shapiro D.; Chubar, O.; Kaznatcheev, K.; Reininger, R.; Sanchez-Hanke, C.; Wang, S.

2011-08-21

The coherent soft x-ray and full polarization control (CSX) beamline at the National Synchrotron Light Source - II (NSLS-II) will deliver 1013 coherent photons per second in the energy range of 0.2-2 keV with a resolving power of 2000. The source, a dual elliptically polarizing undulator (EPU), and beamline optics should be optimized to deliver the highest possible coherent flux in a 10-30 {micro}m spot for use in coherent scattering experiments. Using the computer code Synchrotron Radiation Workshop (SRW), we simulate the photon source and focusing optics in order to investigate the conditions which provide the highest usable coherent intensity on the sample. In particular, we find that an intermediate phasing magnet is needed to correct for the relative phase between the two EPUs and that the optimum phase setting produces a spectrum in which the desired wavelength is slightly red-shifted thus requiring a larger aperture than originally anticipated. This setting is distinct from that which produces an on-axis spectrum similar to a single long undulator. Furthermore, partial coherence calculations, utilizing a multiple electron approach, indicate that a high degree of spatial coherence is still obtained at the sample location when such an aperture is used. The aperture size which maximizes the signal-to-noise ratio of a double-slit experiment is explored. This combination of high coherence and intensity is ideally suited for x-ray ptychography experiments which reconstruct the scattering density from micro-diffraction patterns. This technique is briefly reviewed and the effects on the image quality of proximity to the beamline focus are explored.

Coherent, Short-Pulse X-ray Generation via Relativistic Flying Mirrors

Directory of Open Access Journals (Sweden)

Masaki Kando

2018-04-01

Full Text Available Coherent, Short X-ray pulses are demanded in material science and biology for the study of micro-structures. Currently, large-sized free-electron lasers are used; however, the available beam lines are limited because of the large construction cost. Here we review a novel method to downsize the system as well as providing fully (spatially and temporally coherent pulses. The method is based on the reflection of coherent laser light by a relativistically moving mirror (flying mirror. Due to the double Doppler effect, the reflected pulses are upshifted in frequency and compressed in time. Such mirrors are formed when an intense short laser pulse excites a strongly nonlinear plasma wave in tenuous plasma. Theory, proof-of-principle, experiments, and possible applications are addressed.

The separation of vibrational coherence from ground- and excited-electronic states in P3HT film

KAUST Repository

Song, Yin

2015-06-07

© 2015 AIP Publishing LLC. Concurrence of the vibrational coherence and ultrafast electron transfer has been observed in polymer/fullerene blends. However, it is difficult to experimentally investigate the role that the excited-state vibrational coherence plays during the electron transfer process since vibrational coherence from the ground- and excited-electronic states is usually temporally and spectrally overlapped. Here, we performed 2-dimensional electronic spectroscopy (2D ES) measurements on poly(3-hexylthiophene) (P3HT) films. By Fourier transforming the whole 2D ES datasets (S (λ 1, T∼ 2, λ 3)) along the population time (T∼ 2) axis, we develop and propose a protocol capable of separating vibrational coherence from the ground- and excited-electronic states in 3D rephasing and nonrephasing beating maps (S (λ 1, ν∼ 2, λ 3)). We found that the vibrational coherence from pure excited electronic states appears at positive frequency (+ ν∼ 2) in the rephasing beating map and at negative frequency (- ν∼ 2) in the nonrephasing beating map. Furthermore, we also found that vibrational coherence from excited electronic state had a long dephasing time of 244 fs. The long-lived excited-state vibrational coherence indicates that coherence may be involved in the electron transfer process. Our findings not only shed light on the mechanism of ultrafast electron transfer in organic photovoltaics but also are beneficial for the study of the coherence effect on photoexcited dynamics in other systems.

The separation of vibrational coherence from ground- and excited-electronic states in P3HT film

International Nuclear Information System (INIS)

Song, Yin; Hellmann, Christoph; Stingelin, Natalie; Scholes, Gregory D.

2015-01-01

Concurrence of the vibrational coherence and ultrafast electron transfer has been observed in polymer/fullerene blends. However, it is difficult to experimentally investigate the role that the excited-state vibrational coherence plays during the electron transfer process since vibrational coherence from the ground- and excited-electronic states is usually temporally and spectrally overlapped. Here, we performed 2-dimensional electronic spectroscopy (2D ES) measurements on poly(3-hexylthiophene) (P3HT) films. By Fourier transforming the whole 2D ES datasets (S(λ 1 ,T ~ 2 ,λ 3 )) along the population time (T ~ 2 ) axis, we develop and propose a protocol capable of separating vibrational coherence from the ground- and excited-electronic states in 3D rephasing and nonrephasing beating maps (S(λ 1 ,ν ~ 2 ,λ 3 )). We found that the vibrational coherence from pure excited electronic states appears at positive frequency (+ν ~ 2 ) in the rephasing beating map and at negative frequency (−ν ~ 2 ) in the nonrephasing beating map. Furthermore, we also found that vibrational coherence from excited electronic state had a long dephasing time of 244 fs. The long-lived excited-state vibrational coherence indicates that coherence may be involved in the electron transfer process. Our findings not only shed light on the mechanism of ultrafast electron transfer in organic photovoltaics but also are beneficial for the study of the coherence effect on photoexcited dynamics in other systems

[The sense of coherence and the quality of life of patients treated for breast cancer].

Science.gov (United States)

Motyka, Marek; Dziubak, Małgorzata; Patrycja, Jedrusik

2014-01-01

For women, breast cancer causes great mental stress and affects their functioning in the somatic and psychosocial domain both during the process of diagnostics and therapy, and for a long period of time after the received treatment. A high sense of coherence leads to being better at coping with stress and a can promote the quality of life. The objective of this study was to evaluate the effect of the sense of coherence on the satisfaction with life of post-mastectomy patients, and also on the time which passes between noticing the first symptoms of the disease and reporting to a doctor, and on the timely execution of medical recommendations. The study involved 60 women, age between 30 and 70 years, after a mastectomy procedure due to diagnosed breast cancer. The study used the method of diagnostic survey. The following tools were applied: the Satisfaction with Life Scale (SWLS--E. Diener et al.), the 13-item Sense of Coherence Scale (SOC 13), and a short questionnaire developed by the author. No statistically significant association was found between the level of the sense of coherence and the timely execution of medical recommendations, and the level of the satisfaction with life of the subjects p > 0.05. However, the existence of a statistically significant association was demonstrated between the sense of coherence and the time of reporting to a doctor after noticing disturbing symptoms p < 0.05.

Marked QTc prolongation and Torsades de Pointes in patients with chronic inflammatory arthritis

Directory of Open Access Journals (Sweden)

Pietro Enea Lazzerini

2016-09-01

Full Text Available Mounting evidence indicates that in chronic inflammatory arthritis (CIA, QTc prolongation is frequent and correlates with systemic inflammatory activation. Notably, basic studies demonstrated that inflammatory cytokines induce profound changes in potassium and calcium channels resulting in a prolonging effect on cardiomyocyte action potential duration (APD, thus on the QT interval on the electrocardiogram. Moreover, it has been demonstrated that in RA patients the risk of SCD is significantly increased when compared to non-RA subjects. Conversely, to date no data are available about Torsades de Pointes (TdP prevalence in CIA, and the few case reported considered CIA only an incidental concomitant disease, not contributing factor to TdP development.We report three patients with active CIA developing marked QTc prolongation, in two cases complicated with TdP degenerating to cardiac arrest. In these patients, a blood sample was obtained within 24h from TdP/marked QTc prolongation occurrence and levels of IL-6, TNF-alpha and IL-1 were evaluated. In all three cases, IL-6 was markedly elevated, ~10 to 100 times more than reference values. Moreover, one patient also showed high circulating levels of TNF-alpha and IL-1. In conclusion, active CIA may represent a currently overlooked QT-prolonging risk factor, potentially contributing in the presence of other classical risk factors to TdP occurrence. In particular, a relevant role may be played by elevated circulating IL-6 levels via direct electrophysiological effects on the heart. This observation should be carefully kept in mind, particularly when recognizable risk factors are already present and/or the addition of QT-prolonging drugs is required.

The coherent state variational algorithm and the QCD deconfinement phase transition

International Nuclear Information System (INIS)

Somsky, W.R.

1989-01-01

This thesis describes the coherent state variational algorithm, its implementation in a recently completed set of computer programs, and its application to the study of the QCD deconfinement phase transition. The coherent state variational algorithm is a computational method for studying the large-N limit of non-abelian gauge theories by direct exploitation of the classical nature of this limit. Unlike Monte Carlo methods, this technique is applicable to both euclidean and hamiltonian formulations of lattice gauge theories and is deterministic, rather than statistical, in nature. The first part of this thesis presents the theoretical basis of the coherent state algorithm and describes the application of the algorithm, to non-abelian lattice gauge theories. The second part describes the symbolic methods involved in the computer implementation of the coherent state algorithm and gives an overview of the programs which form the full coherent state implementation. The final part of this thesis discusses the application of the coherent state algorithm to the study of the QCD deconfinement phase transition at large N. The results obtained are indicative of a second-order transition for lattices of temporal extent N ν = 1 and N τ = 2 in both three and four space-time dimensions

Coherent states on Hilbert modules

International Nuclear Information System (INIS)

Ali, S Twareque; Bhattacharyya, T; Roy, S S

2011-01-01

We generalize the concept of coherent states, traditionally defined as special families of vectors on Hilbert spaces, to Hilbert modules. We show that Hilbert modules over C*-algebras are the natural settings for a generalization of coherent states defined on Hilbert spaces. We consider those Hilbert C*-modules which have a natural left action from another C*-algebra, say A. The coherent states are well defined in this case and they behave well with respect to the left action by A. Certain classical objects like the Cuntz algebra are related to specific examples of coherent states. Finally we show that coherent states on modules give rise to a completely positive definite kernel between two C*-algebras, in complete analogy to the Hilbert space situation. Related to this, there is a dilation result for positive operator-valued measures, in the sense of Naimark. A number of examples are worked out to illustrate the theory. Some possible physical applications are also mentioned.

Coherent states in quantum physics

CERN Document Server

Gazeau, Jean-Pierre

2009-01-01

This self-contained introduction discusses the evolution of the notion of coherent states, from the early works of Schrödinger to the most recent advances, including signal analysis. An integrated and modern approach to the utility of coherent states in many different branches of physics, it strikes a balance between mathematical and physical descriptions.Split into two parts, the first introduces readers to the most familiar coherent states, their origin, their construction, and their application and relevance to various selected domains of physics. Part II, mostly based on recent original results, is devoted to the question of quantization of various sets through coherent states, and shows the link to procedures in signal analysis. Title: Coherent States in Quantum Physics Print ISBN: 9783527407095 Author(s): Gazeau, Jean-Pierre eISBN: 9783527628292 Publisher: Wiley-VCH Dewey: 530.12 Publication Date: 23 Sep, 2009 Pages: 360 Category: Science, Science: Physics LCCN: Language: English Edition: N/A LCSH:

Coherent vs Incoherent Emission from Semiconductor Structures after Resonant Femtosecond Excitation

Science.gov (United States)

Gurioli, Massimo; Bogani, Franco; Ceccherini, Simone; Colocci, Marcello

1997-04-01

We show that an interferometric correlation measurement with fs time resolution provides an unambiguous discrimination between coherent and incoherent emission after resonant femtosecond excitation. The experiment directly probes the most important difference between the two emissions, that is, the phase correlation with the excitation pulse. The comparison with cw frequency resolved measurements demonstrates that the relationship between coherent and incoherent emission is similar under femtosecond and steady-state excitation.

Observation of a Time Quasicrystal and Its Transition to a Superfluid Time Crystal

Science.gov (United States)

Autti, S.; Eltsov, V. B.; Volovik, G. E.

2018-05-01

We report experimental realization of a quantum time quasicrystal and its transformation to a quantum time crystal. We study Bose-Einstein condensation of magnons, associated with coherent spin precession, created in a flexible trap in superfluid 3He-B . Under a periodic drive with an oscillating magnetic field, the coherent spin precession is stabilized at a frequency smaller than that of the drive, demonstrating spontaneous breaking of discrete time translation symmetry. The induced precession frequency is incommensurate with the drive, and hence, the obtained state is a time quasicrystal. When the drive is turned off, the self-sustained coherent precession lives a macroscopically long time, now representing a time crystal with broken symmetry with respect to continuous time translations. Additionally, the magnon condensate manifests spin superfluidity, justifying calling the obtained state a time supersolid or a time supercrystal.

Asymmetry and coherence weight of quantum states

Science.gov (United States)

Bu, Kaifeng; Anand, Namit; Singh, Uttam

2018-03-01

The asymmetry of quantum states is an important resource in quantum information processing tasks such as quantum metrology and quantum communication. In this paper, we introduce the notion of asymmetry weight—an operationally motivated asymmetry quantifier in the resource theory of asymmetry. We study the convexity and monotonicity properties of asymmetry weight and focus on its interplay with the corresponding semidefinite programming (SDP) forms along with its connection to other asymmetry measures. Since the SDP form of asymmetry weight is closely related to asymmetry witnesses, we find that the asymmetry weight can be regarded as a (state-dependent) asymmetry witness. Moreover, some specific entanglement witnesses can be viewed as a special case of an asymmetry witness—which indicates a potential connection between asymmetry and entanglement. We also provide an operationally meaningful coherence measure, which we term coherence weight, and investigate its relationship to other coherence measures like the robustness of coherence and the l1 norm of coherence. In particular, we show that for Werner states in any dimension d all three coherence quantifiers, namely, the coherence weight, the robustness of coherence, and the l1 norm of coherence, are equal and are given by a single letter formula.

Statistical and coherence properties of radiation from X-ray free electron lasers

International Nuclear Information System (INIS)

Saldin, E.L.; Schneidmiller, E.A.; Yurkov, M.V.

2009-12-01

We describe statistical and coherence properties of the radiation from X-ray free electron lasers (XFEL). It is shown that the X-ray FEL radiation before saturation is described with gaussian statistics. Particularly important is the case of the optimized X-ray FEL, studied in detail. Applying similarity techniques to the results of numerical simulations allowed us to find universal scaling relations for the main characteristics of an X-ray FEL operating in the saturation regime: efficiency, coherence time and degree of transverse coherence. We find that with an appropriate normalization of these quantities, they are functions of only the ratio of the geometrical emittance of the electron beam to the radiation wavelength. Statistical and coherence properties of the higher harmonics of the radiation are highlighted as well. (orig.)

Statistical and coherence properties of radiation from X-ray free electron lasers

Energy Technology Data Exchange (ETDEWEB)

Saldin, E L; Schneidmiller, E A; Yurkov, M V

2009-12-15

We describe statistical and coherence properties of the radiation from X-ray free electron lasers (XFEL). It is shown that the X-ray FEL radiation before saturation is described with gaussian statistics. Particularly important is the case of the optimized X-ray FEL, studied in detail. Applying similarity techniques to the results of numerical simulations allowed us to find universal scaling relations for the main characteristics of an X-ray FEL operating in the saturation regime: efficiency, coherence time and degree of transverse coherence. We find that with an appropriate normalization of these quantities, they are functions of only the ratio of the geometrical emittance of the electron beam to the radiation wavelength. Statistical and coherence properties of the higher harmonics of the radiation are highlighted as well. (orig.)

Coherent states: a contemporary panorama Coherent states: a contemporary panorama

Science.gov (United States)

Twareque Ali, S.; Antoine, Jean-Pierre; Bagarello, Fabio; Gazeau, Jean-Pierre

2012-06-01

Coherent states (CS) of the harmonic oscillator (also called canonical CS) were introduced in 1926 by Schrödinger in answer to a remark by Lorentz on the classical interpretation of the wave function. They were rediscovered in the early 1960s, first (somewhat implicitly) by Klauder in the context of a novel representation of quantum states, then by Glauber and Sudarshan for the description of coherence in lasers. Since then, CS have grown into an extremely rich domain that pervades almost every corner of physics and have also led to the development of several flourishing topics in mathematics. Along the way, a number of review articles have appeared in the literature, devoted to CS, notably the 1985 reprint volume of Klauder and Skagerstam [1], the 1990 review paper by Zhang et al [2], the 1993 Oak Ridge Conference [3] and the 1995 review paper by Ali et al [4]. Textbooks also have been published, among which one might mention the ground breaking text of Perelomov [5] focusing on the group-theoretical aspects, that of Ali et al [6]1 analyzing systematically the mathematical structure beyond the group-theoretical approach and also the relation to wavelet analysis, that of Dodonov and Man'ko [7] mostly devoted to quantum optics, that of Gazeau [8] more oriented towards the physical, probabilistic and quantization aspects, and finally the very recent one by Combescure and Robert [9]. In retrospect, one can see that the development of CS has gone through a two-phase transition. First, the (simultaneous) discovery in 1972 by Gilmore and Perelomov that CS were rooted in group theory, then the realization that CS can be defined in a purely algebraic way, as an eigenvalue problem or by a series expansion (Malkin and Man'ko 1969, Barut and Girardello 1971, Gazeau and Klauder 1999; references to the original articles may be found in the textbooks quoted above). Both facts resulted in an explosive expansion of the CS literature. We thought, therefore, that the time was ripe

Identification of individual coherent sets associated with flow trajectories using Coherent Structure Coloring

Science.gov (United States)

Schlueter-Kuck, Kristy; Dabiri, John

2017-11-01

In recent years, there has been a proliferation of techniques that aim to characterize fluid flow kinematics on the basis of Lagrangian trajectories of collections of tracer particles. Most of these techniques depend on presence of tracer particles that are initially closely-spaced, in order to compute local gradients of their trajectories. In many applications, the requirement of close tracer spacing cannot be satisfied, especially when the tracers are naturally occurring and their distribution is dictated by the underlying flow. Moreover, current methods often focus on determination of the boundaries of coherent sets, whereas in practice it is often valuable to identify the complete set of trajectories that are coherent with an individual trajectory of interest. We extend the concept of Coherent Structure Coloring to achieve identification of the coherent set associated with individual Lagrangian trajectories. This algorithm is proven successful in identifying coherent structures of varying complexities in canonical unsteady flows. Importantly, although the method is demonstrated here in the context of fluid flow kinematics, the generality of the approach allows for its potential application to other unsupervised clustering problems in dynamical systems. This work was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

High-speed optical coherence tomography signal processing on GPU

International Nuclear Information System (INIS)

Li Xiqi; Shi Guohua; Zhang Yudong

2011-01-01

The signal processing speed of spectral domain optical coherence tomography (SD-OCT) has become a bottleneck in many medical applications. Recently, a time-domain interpolation method was proposed. This method not only gets a better signal-to noise ratio (SNR) but also gets a faster signal processing time for the SD-OCT than the widely used zero-padding interpolation method. Furthermore, the re-sampled data is obtained by convoluting the acquired data and the coefficients in time domain. Thus, a lot of interpolations can be performed concurrently. So, this interpolation method is suitable for parallel computing. An ultra-high optical coherence tomography signal processing can be realized by using graphics processing unit (GPU) with computer unified device architecture (CUDA). This paper will introduce the signal processing steps of SD-OCT on GPU. An experiment is performed to acquire a frame SD-OCT data (400A-linesx2048 pixel per A-line) and real-time processed the data on GPU. The results show that it can be finished in 6.208 milliseconds, which is 37 times faster than that on Central Processing Unit (CPU).

Coherency Identification of Generators Using a PAM Algorithm for Dynamic Reduction of Power Systems

Directory of Open Access Journals (Sweden)

Seung-Il Moon

2012-11-01

Full Text Available This paper presents a new coherency identification method for dynamic reduction of a power system. To achieve dynamic reduction, coherency-based equivalence techniques divide generators into groups according to coherency, and then aggregate them. In order to minimize the changes in the dynamic response of the reduced equivalent system, coherency identification of the generators should be clearly defined. The objective of the proposed coherency identification method is to determine the optimal coherent groups of generators with respect to the dynamic response, using the Partitioning Around Medoids (PAM algorithm. For this purpose, the coherency between generators is first evaluated from the dynamic simulation time response, and in the proposed method this result is then used to define a dissimilarity index. Based on the PAM algorithm, the coherent generator groups are then determined so that the sum of the index in each group is minimized. This approach ensures that the dynamic characteristics of the original system are preserved, by providing the optimized coherency identification. To validate the effectiveness of the technique, simulated cases with an IEEE 39-bus test system are evaluated using PSS/E. The proposed method is compared with an existing coherency identification method, which uses the K-means algorithm, and is found to provide a better estimate of the original system. 

Spatial coherence of flood-rich and flood-poor periods across Germany

Science.gov (United States)

Merz, Bruno; Dung, Nguyen Viet; Apel, Heiko; Gerlitz, Lars; Schröter, Kai; Steirou, Eva; Vorogushyn, Sergiy

2018-04-01

Despite its societal relevance, the question whether fluctuations in flood occurrence or magnitude are coherent in space has hardly been addressed in quantitative terms. We investigate this question for Germany by analysing fluctuations in annual maximum series (AMS) values at 68 discharge gauges for the common time period 1932-2005. We find remarkable spatial coherence across Germany given its different flood regimes. For example, there is a tendency that flood-rich/-poor years in sub-catchments of the Rhine basin, which are dominated by winter floods, coincide with flood-rich/-poor years in the southern sub-catchments of the Danube basin, which have their dominant flood season in summer. Our findings indicate that coherence is caused rather by persistence in catchment wetness than by persistent periods of higher/lower event precipitation. Further, we propose to differentiate between event-type and non-event-type coherence. There are quite a number of hydrological years with considerable non-event-type coherence, i.e. AMS values of the 68 gauges are spread out through the year but in the same magnitude range. Years with extreme flooding tend to be of event-type and non-coherent, i.e. there is at least one precipitation event that affects many catchments to various degree. Although spatial coherence is a remarkable phenomenon, and large-scale flooding across Germany can lead to severe situations, extreme magnitudes across the whole country within one event or within one year were not observed in the investigated period.

Changes in tumor cell response due to prolonged dose delivery times in fractionated radiation therapy

International Nuclear Information System (INIS)

Paganetti, Harald

2005-01-01

Purpose: Dynamic radiation therapy, such as intensity-modulated radiation therapy, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The cellular damage after a full treatment may depend on the dose rate, because sublethal radiation damage can be repaired more efficiently during prolonged dose delivery. The goal of this study was to investigate the significance of this effect in fractionated radiation therapy. Methods and Materials: The lethal/potentially lethal model was used to calculate lesion induction rates for repairable and nonrepairable lesions. Dose rate effects were analyzed for 9 different cell lines (8 human tumor xenografts and a C3H10T1/2 cell line). The effects of single-fraction as well as fractionated irradiation for different dose rates were studied. Results: Significant differences can be seen for dose rates lower than about 0.1 Gy/min for all cell lines considered. For 60 Gy delivered in 30 fractions, the equivalent dose is reduced by between 1.3% and 12% comparing 2 Gy delivery over 30 min per fraction with 2 Gy delivery over 1 min per fraction. The effect is higher for higher doses per fraction. Furthermore, the results show that dose rate effects do not show a simple correlation with the α/β ratio for ratios between 3 Gy and 31 Gy. Conclusions: If the total dose delivery time for a treatment fraction in radiation therapy increases to about 20 min, a correction for dose rate effects may have to be considered in treatment planning. Adjustments in effective dose may be necessary when comparing intensity-modulated radiation therapy with conventional treatment plans

Time-dependent wave front propagation simulation of a hard x-ray split-and-delay unit: Towards a measurement of the temporal coherence properties of x-ray free electron lasers

Directory of Open Access Journals (Sweden)

S. Roling

2014-11-01

Full Text Available For the European x-ray free electron laser (XFEL a split-and-delay unit based on geometrical wavefront beam splitting and multilayer mirrors is built which covers the range of photon energies from 5 keV up to 20 keV. Maximum delays between Δτ=±2.5  ps at hν=20  keV and up to Δτ=±23  ps at hν=5  keV will be possible. Time-dependent wave-optics simulations have been performed by means of Synchrotron Radiation Workshop software for XFEL pulses at hν=5  keV. The XFEL radiation was simulated using results of time-dependent simulations applying the self-amplified spontaneous emission code FAST. Main features of the optical layout, including diffraction on the beam splitter edge and optics imperfections measured with a nanometer optic component measuring machine slope measuring profiler, were taken into account. The impact of these effects on the characterization of the temporal properties of XFEL pulses is analyzed. An approach based on fast Fourier transformation allows for the evaluation of the temporal coherence despite large wavefront distortions caused by the optics imperfections. In this way, the fringes resulting from time-dependent two-beam interference can be filtered and evaluated yielding a coherence time of τ_{c}=0.187  fs (HWHM for real, nonperfect mirrors, while for ideal mirrors a coherence time of τ_{c}=0.191  fs (HWHM is expected.

Cryptocurrency price drivers: Wavelet coherence analysis revisited.

Science.gov (United States)

Phillips, Ross C; Gorse, Denise

2018-01-01

Cryptocurrencies have experienced recent surges in interest and price. It has been discovered that there are time intervals where cryptocurrency prices and certain online and social media factors appear related. In addition it has been noted that cryptocurrencies are prone to experience intervals of bubble-like price growth. The hypothesis investigated here is that relationships between online factors and price are dependent on market regime. In this paper, wavelet coherence is used to study co-movement between a cryptocurrency price and its related factors, for a number of examples. This is used alongside a well-known test for financial asset bubbles to explore whether relationships change dependent on regime. The primary finding of this work is that medium-term positive correlations between online factors and price strengthen significantly during bubble-like regimes of the price series; this explains why these relationships have previously been seen to appear and disappear over time. A secondary finding is that short-term relationships between the chosen factors and price appear to be caused by particular market events (such as hacks / security breaches), and are not consistent from one time interval to another in the effect of the factor upon the price. In addition, for the first time, wavelet coherence is used to explore the relationships between different cryptocurrencies.

COHERENT Experiment: current status

International Nuclear Information System (INIS)

Akimov, D; Belov, V; Bolozdynya, A; Burenkov, A; Albert, J B; Del Valle Coello, M; D’Onofrio, M; Awe, C; Barbeau, P S; Cervantes, M; Becker, B; Cabrera-Palmer, B; Collar, J I; Cooper, R J; Cooper, R L; Cuesta, C; Detwiler, J; Eberhardt, A; Dean, D; Dolgolenko, A G

2017-01-01

The COHERENT Collaboration is realizing a long term neutrino physics research program. The main goals of the program are to detect and study elastic neutrino-nucleus scattering (CEνNS). This process is predicted by Standard Model but it has never been observed experimentally because of the very low energy of the recoil nucleus. COHERENT is using different detector technologies: CsI[Na] and NaI scintillator crystals, a single-phase liquid Ar and a Ge detectors. The placement of all the detector setups is in the basement of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The current status of the COHERENT experimental program is presented. (paper)

Quench of non-Markovian coherence in the deep sub-Ohmic spin–boson model: A unitary equilibration scheme

International Nuclear Information System (INIS)

Yao, Yao

2015-01-01

The deep sub-Ohmic spin–boson model shows a longstanding non-Markovian coherence at low temperature. Motivating to quench this robust coherence, the thermal effect is unitarily incorporated into the time evolution of the model, which is calculated by the adaptive time-dependent density matrix renormalization group algorithm combined with the orthogonal polynomials theory. Via introducing a unitary heating operator to the bosonic bath, the bath is heated up so that a majority portion of the bosonic excited states is occupied. It is found in this situation the coherence of the spin is quickly quenched even in the coherent regime, in which the non-Markovian feature dominates. With this finding we come up with a novel way to implement the unitary equilibration, the essential term of the eigenstate-thermalization hypothesis, through a short-time evolution of the model

Coherence-driven argumentation to norm consensus

NARCIS (Netherlands)

Joseph, S.; Prakken, H.

2009-01-01

In this paper coherence-based models are proposed as an alternative to logic-based BDI and argumentation models for the reasoning of normative agents. A model is provided for how two coherence-based agents can deliberate on how to regulate a domain of interest. First a deductive coherence model

Monitoring Bedfast Ice and Ice Phenology in Lakes of the Lena River Delta Using TerraSAR-X Backscatter and Coherence Time Series

Directory of Open Access Journals (Sweden)

Sofia Antonova

2016-11-01

Full Text Available Thermokarst lakes and ponds are major elements of permafrost landscapes, occupying up to 40% of the land area in some Arctic regions. Shallow lakes freeze to the bed, thus preventing permafrost thaw underneath them and limiting the length of the period with greenhouse gas production in the unfrozen lake sediments. Radar remote sensing permits to distinguish lakes with bedfast ice due to the difference in backscatter intensities from bedfast and floating ice. This study investigates the potential of a unique time series of three-year repeat-pass TerraSAR-X (TSX imagery with high temporal (11 days and spatial (10 m resolution for monitoring bedfast ice as well as ice phenology of lakes in the zone of continuous permafrost in the Lena River Delta, Siberia. TSX backscatter intensity is shown to be an excellent tool for monitoring floating versus bedfast lake ice as well as ice phenology. TSX-derived timing of ice grounding and the ice growth model CLIMo are used to retrieve the ice thicknesses of the bedfast ice at points where in situ ice thickness measurements were available. Comparison shows good agreement in the year of field measurements. Additionally, for the first time, an 11-day sequential interferometric coherence time series is analyzed as a supplementary approach for the bedfast ice monitoring. The coherence time series detects most of the ice grounding as well as spring snow/ice melt onset. Overall, the results show the great value of TSX time series for monitoring Arctic lake ice and provide a basis for various applications: for instance, derivation of shallow lakes bathymetry, evaluation of winter water resources and locating fish winter habitat as well as estimation of taliks extent in permafrost.

Coherent fine scale eddies in turbulence transition of spatially-developing mixing layer

International Nuclear Information System (INIS)

Wang, Y.; Tanahashi, M.; Miyauchi, T.

2007-01-01

To investigate the relationship between characteristics of the coherent fine scale eddy and a laminar-turbulent transition, a direct numerical simulation (DNS) of a spatially-developing turbulent mixing layer with Re ω,0 = 700 was conducted. On the onset of the transition, strong coherent fine scale eddies appears in the mixing layer. The most expected value of maximum azimuthal velocity of the eddy is 2.0 times Kolmogorov velocity (u k ), and decreases to 1.2u k , which is an asymptotic value in the fully-developed state, through the transition. The energy dissipation rate around the eddy is twice as high compared with that in the fully-developed state. However, the most expected diameter and eigenvalues ratio of strain rate acting on the coherent fine scale eddy are maintained to be 8 times Kolmogorov length (η) and α:β:γ = -5:1:4 in the transition process. In addition to Kelvin-Helmholtz rollers, rib structures do not disappear in the transition process and are composed of lots of coherent fine scale eddies in the fully-developed state instead of a single eddy observed in early stage of the transition or in laminar flow

Extensive deep vein thrombosis following prolonged gaming (‘gamer’s thrombosis’): a case report

Science.gov (United States)

2013-01-01

Introduction The average time spent playing video games is increasing. Prolonged immobility associated with gaming may therefore be an important risk factor for venous thromboembolism. We report a case of deep vein thrombosis associated with prolonged playing of PlayStation® games. Case presentation A 31-year-old Caucasian man, an exterior painter, presented with a three-day history of left leg pain and swelling after playing PlayStation® games for almost eight hours a day for four consecutive days. Doppler ultrasound of the left leg confirmed extensive left leg deep venous thrombosis requiring thrombolysis and anticoagulation. Conclusions Video gaming should be considered a risk factor for venous thromboembolism. Further studies are needed to estimate the degree of risk associated with prolonged periods of playing video games, and education for preventing venous thrombosis should be provided to gamers. PMID:24192285

Pharmacometabolomic approach to predict QT prolongation in guinea pigs.

Directory of Open Access Journals (Sweden)

Jeonghyeon Park

Full Text Available Drug-induced torsades de pointes (TdP, a life-threatening arrhythmia associated with prolongation of the QT interval, has been a significant reason for withdrawal of several medicines from the market. Prolongation of the QT interval is considered as the best biomarker for predicting the torsadogenic risk of a new chemical entity. Because of the difficulty assessing the risk for TdP during drug development, we evaluated the metabolic phenotype for predicting QT prolongation induced by sparfloxacin, and elucidated the metabolic pathway related to the QT prolongation. We performed electrocardiography analysis and liquid chromatography-mass spectroscopy-based metabolic profiling of plasma samples obtained from 15 guinea pigs after administration of sparfloxacin at doses of 33.3, 100, and 300 mg/kg. Principal component analysis and partial least squares modelling were conducted to select the metabolites that substantially contributed to the prediction of QT prolongation. QTc increased significantly with increasing dose (r = 0.93. From the PLS analysis, the key metabolites that showed the highest variable importance in the projection values (>1.5 were selected, identified, and used to determine the metabolic network. In particular, cytidine-5'-diphosphate (CDP, deoxycorticosterone, L-aspartic acid and stearic acid were found to be final metabolomic phenotypes for the prediction of QT prolongation. Metabolomic phenotypes for predicting drug-induced QT prolongation of sparfloxacin were developed and can be applied to cardiac toxicity screening of other drugs. In addition, this integrative pharmacometabolomic approach would serve as a good tool for predicting pharmacodynamic or toxicological effects caused by changes in dose.

Prolonged transition time between colostrum and mature milk in a bear, the giant panda, Ailuropoda melanoleuca

OpenAIRE

Griffiths, Katharine; Rong, Hou; Wang, Hairui; Zhang, Zhihe; Zhang, Tong; Watson, David G.; Burchmore, Richard; Loeffler, I.Kati; Kennedy, Malcolm

2015-01-01

Bears produce the most altricial neonates of any placental mammal. We hypothesized that the transition from colostrum to mature milk in bears reflects a temporal and biochemical adaptation for altricial development and immune protection. Comparison of bear milks with milks of other eutherians yielded distinctive protein profiles. Proteomic and metabolomic analysis of serial milk samples collected from six giant pandas showed a prolonged transition from colostrum to main-phase lactation over a...

Coherent quantum logic

International Nuclear Information System (INIS)

Finkelstein, D.

1987-01-01

The von Neumann quantum logic lacks two basic symmetries of classical logic, that between sets and classes, and that between lower and higher order predicates. Similarly, the structural parallel between the set algebra and linear algebra of Grassmann and Peano was left incomplete by them in two respects. In this work a linear algebra is constructed that completes this correspondence and is interpreted as a new quantum logic that restores these invariances, and as a quantum set theory. It applies to experiments with coherent quantum phase relations between the quantum and the apparatus. The quantum set theory is applied to model a Lorentz-invariant quantum time-space complex

Topical Drug Formulations for Prolonged Corneal Anesthesia

Science.gov (United States)

Wang, Liqiang; Shankarappa, Sahadev A.; Tong, Rong; Ciolino, Joseph B.; Tsui, Jonathan H.; Chiang, Homer H.; Kohane, Daniel S.

2013-01-01

Purpose Ocular local anesthetics (OLA’s) currently used in routine clinical practice for corneal anesthesia are short acting and their ability to delay corneal healing makes them unsuitable for long-term use. In this study, we examined the effect on the duration of corneal anesthesia of the site-1 sodium channel blocker tetrodotoxin (TTX), applied with either proparacaine or the chemical permeation enhancer OTAB. The effect of test solutions on corneal healing was also studied. Methods Solutions of TTX, proparacaine, and OTAB, singly or in combination were applied topically to the rat cornea. The blink response, an indirect measure of corneal sensitivity, was recorded using a Cochet-Bonnet esthesiometer, and the duration of corneal anesthesia calculated. The effect of test compounds on the rate of corneal epithelialization was studied in vivo following corneal debridement. Results Combination of TTX and proparacaine resulted in corneal anesthesia that was 8–10 times longer in duration than that from either drug administered alone, while OTAB did not prolong anesthesia. The rate of corneal healing was moderately delayed following co-administration of TTX and proparacaine. Conclusion Co-administration of TTX and proparacaine significantly prolonged corneal anesthesia but in view of delayed corneal re-epithelialization, caution is suggested in use of the combination. PMID:23615270

Effect of quantum lattice fluctuations on quantum coherent oscillations in a coherently driven quantum dot-cavity system

International Nuclear Information System (INIS)

Zhu, Ka-Di; Li, Wai-Sang

2003-01-01

The quantum coherent oscillations in a coherently driven quantum dot-cavity system with the presence of strong exciton-phonon interactions are investigated theoretically in a fully quantum treatment. It is shown that even at zero temperature, the strong exciton-phonon interactions still affect the quantum coherent oscillations significantly

Quantum coherence and correlations in quantum system

Science.gov (United States)

Xi, Zhengjun; Li, Yongming; Fan, Heng

2015-01-01

Criteria of measure quantifying quantum coherence, a unique property of quantum system, are proposed recently. In this paper, we first give an uncertainty-like expression relating the coherence and the entropy of quantum system. This finding allows us to discuss the relations between the entanglement and the coherence. Further, we discuss in detail the relations among the coherence, the discord and the deficit in the bipartite quantum system. We show that, the one-way quantum deficit is equal to the sum between quantum discord and the relative entropy of coherence of measured subsystem. PMID:26094795

Painlevé IV coherent states

Energy Technology Data Exchange (ETDEWEB)

Bermudez, David, E-mail: david.bermudez@weizmann.ac.il [Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100 (Israel); Departamento de Física, Cinvestav, A.P. 14-740, 07000 México D.F. (Mexico); Contreras-Astorga, Alonso, E-mail: aloncont@iun.edu [Department of Mathematics and Actuarial Science, Indiana University Northwest, 3400 Broadway, Gary IN 46408 (United States); Departamento de Física, Cinvestav, A.P. 14-740, 07000 México D.F. (Mexico); Fernández C, David J., E-mail: david@fis.cinvestav.mx [Departamento de Física, Cinvestav, A.P. 14-740, 07000 México D.F. (Mexico)

2014-11-15

A simple way to find solutions of the Painlevé IV equation is by identifying Hamiltonian systems with third-order differential ladder operators. Some of these systems can be obtained by applying supersymmetric quantum mechanics (SUSY QM) to the harmonic oscillator. In this work, we will construct families of coherent states for such subset of SUSY partner Hamiltonians which are connected with the Painlevé IV equation. First, these coherent states are built up as eigenstates of the annihilation operator, then as displaced versions of the extremal states, both involving the related third-order ladder operators, and finally as extremal states which are also displaced but now using the so called linearized ladder operators. To each SUSY partner Hamiltonian corresponds two families of coherent states: one inside the infinite subspace associated with the isospectral part of the spectrum and another one in the finite subspace generated by the states created through the SUSY technique. - Highlights: • We use SUSY QM to obtain Hamiltonians with third-order differential ladder operators. • We show that these systems are related with the Painlevé IV equation. • We apply different definitions of coherent states to these Hamiltonians using the third-order ladder operators and some linearized ones. • We construct families of coherent states for such systems, which we called Painlevé IV coherent states.

Painlevé IV coherent states

International Nuclear Information System (INIS)

Bermudez, David; Contreras-Astorga, Alonso; Fernández C, David J.

2014-01-01

A simple way to find solutions of the Painlevé IV equation is by identifying Hamiltonian systems with third-order differential ladder operators. Some of these systems can be obtained by applying supersymmetric quantum mechanics (SUSY QM) to the harmonic oscillator. In this work, we will construct families of coherent states for such subset of SUSY partner Hamiltonians which are connected with the Painlevé IV equation. First, these coherent states are built up as eigenstates of the annihilation operator, then as displaced versions of the extremal states, both involving the related third-order ladder operators, and finally as extremal states which are also displaced but now using the so called linearized ladder operators. To each SUSY partner Hamiltonian corresponds two families of coherent states: one inside the infinite subspace associated with the isospectral part of the spectrum and another one in the finite subspace generated by the states created through the SUSY technique. - Highlights: • We use SUSY QM to obtain Hamiltonians with third-order differential ladder operators. • We show that these systems are related with the Painlevé IV equation. • We apply different definitions of coherent states to these Hamiltonians using the third-order ladder operators and some linearized ones. • We construct families of coherent states for such systems, which we called Painlevé IV coherent states

Sense of Coherence and Gambling: Exploring the Relationship Between Sense of Coherence, Gambling Behaviour and Gambling-Related Harm.

Science.gov (United States)

Langham, Erika; Russell, Alex M T; Hing, Nerilee; Gainsbury, Sally M

2017-06-01

Understanding why some people experience problems with gambling whilst others are able to restrict gambling to recreational levels is still largely unexplained. One potential explanation is through salutogenesis, which is a health promotion approach of understanding factors which move people towards health rather than disease. An important aspect of salutogenesis is sense of coherence. Individuals with stronger sense of coherence perceive their environment as comprehensible, manageable and meaningful. The present study examined the relationship of individuals' sense of coherence on their gambling behaviour and experience of gambling related harm. This exploratory study utilised an archival dataset (n = 1236) from an online, cross sectional survey of people who had experienced negative consequences from gambling. In general, a stronger sense of coherence was related to lower problem gambling severity. When gambling behaviour was controlled for, sense of coherence was significantly related to the experience of individual gambling harms. A strong sense of coherence can be seen as a protective factor against problematic gambling behaviour, and subsequent gambling related harms. These findings support the value of both primary and tertiary prevention strategies that strengthen sense of coherence as a harm minimisation strategy. The present study demonstrates the potential value of, and provides clear direction for, considering sense of coherence in order to understand gambling-related issues.

Graphics processing unit accelerated intensity-based optical coherence tomography angiography using differential frames with real-time motion correction.

Science.gov (United States)

Watanabe, Yuuki; Takahashi, Yuhei; Numazawa, Hiroshi

2014-02-01

We demonstrate intensity-based optical coherence tomography (OCT) angiography using the squared difference of two sequential frames with bulk-tissue-motion (BTM) correction. This motion correction was performed by minimization of the sum of the pixel values using axial- and lateral-pixel-shifted structural OCT images. We extract the BTM-corrected image from a total of 25 calculated OCT angiographic images. Image processing was accelerated by a graphics processing unit (GPU) with many stream processors to optimize the parallel processing procedure. The GPU processing rate was faster than that of a line scan camera (46.9 kHz). Our OCT system provides the means of displaying structural OCT images and BTM-corrected OCT angiographic images in real time.

RD50 Prolongation Request 2018

CERN Document Server

Casse, Gianluigi

2018-01-01

With this document, we request the prolongation of the CERN RD50 research program for 5 years. A very brief historical review of the RD50 research program since the RD50 project approval by the Research Board in the year 2002 is presented and the biggest RD50 achievements are highlighted. The present composition of the collaboration, its organizational structure, and the research methodology are described. The role of RD50 in the present various upgrade and research programs of the LHC Experiments community is given and the overall work plan explained. Finally, a detailed 5-years work program with precise milestones and deliverables for the various research activities is presented. We conclude with our prolongation request towards the LHCC.

Quantum Processes Which Do Not Use Coherence

Directory of Open Access Journals (Sweden)

Benjamin Yadin

2016-11-01

Full Text Available A major signature of quantum mechanics beyond classical physics is coherence, the existence of superposition states. The recently developed resource theory of quantum coherence allows the formalization of incoherent operations—those operations which cannot create coherence. We identify the set of operations which additionally do not use coherence. These are such that coherence cannot be exploited by a classical observer, who measures incoherent properties of the system, to go beyond classical dynamics. We give a physical interpretation in terms of interferometry and prove a dilation theorem, showing how these operations can always be constructed by the system interacting, in an incoherent way, with an ancilla. Such a physical justification is not known for the incoherent operations; thus, our results lead to a physically well-motivated resource theory of coherence. Next, we investigate the implications for coherence in multipartite systems. We show that quantum correlations can be defined naturally with respect to a fixed basis, providing a link between coherence and quantum discord. We demonstrate the interplay between these two quantities in the operations that we study and suggest implications for the theory of quantum discord by relating these operations to those which cannot create discord.

Effects of quantum coherence on work statistics

Science.gov (United States)

Xu, Bao-Ming; Zou, Jian; Guo, Li-Sha; Kong, Xiang-Mu

2018-05-01

In the conventional two-point measurement scheme of quantum thermodynamics, quantum coherence is destroyed by the first measurement. But as we know the coherence really plays an important role in the quantum thermodynamics process, and how to describe the work statistics for a quantum coherent process is still an open question. In this paper, we use the full counting statistics method to investigate the effects of quantum coherence on work statistics. First, we give a general discussion and show that for a quantum coherent process, work statistics is very different from that of the two-point measurement scheme, specifically the average work is increased or decreased and the work fluctuation can be decreased by quantum coherence, which strongly depends on the relative phase, the energy level structure, and the external protocol. Then, we concretely consider a quenched one-dimensional transverse Ising model and show that quantum coherence has a more significant influence on work statistics in the ferromagnetism regime compared with that in the paramagnetism regime, so that due to the presence of quantum coherence the work statistics can exhibit the critical phenomenon even at high temperature.

High-dose radiation therapy alone for inoperable non-small cell lung cancer. Experience with prolonged overall treatment times

International Nuclear Information System (INIS)

Willers, H.; Wuerschmidt, F.; Buenemann, H.; Heilmann, H.P.

1998-01-01

The purpose of this study was to determine the impact of overall treatment time on long-term survival after high-dose radiation therapy alone for inoperable non-small cell lung cancer (NSCLC). Between 1978 and 1990, 229 patients with stage I-III disease and Karnofsky Performance Scores of 80-100 received a conventionally fractionated total dose of 70 Gy through a split-course technique. After a first treatment course of 40 or 50 Gy, a rest aging was performed and only patients without any contraindications, such as newly diagnosed distant metastases or serious deterioration of performance status, were given a second course. In 83% of patients this break lasted for 4-6 weeks. Overall treatment time ranged between 7 and 24 weeks (median 12 weeks). Median follow-up time was 6.6 years (range 4.0-9.3 years). Actuarial overall survival rates at 2 and 5 years were 28% and 7% respectively. Complete radiological tumor response was observed in 31% of patients, and was found to be the strongest positive predictor of survival with 2- and 5-year rates of 50% and 12% respectively compared with 17% and 4% for patients without complete response. Treatment duration was not found to be a significant prognostic factor in univariate or multivariate analysis. For overall treatment times of 7-11 weeks (n=50), 12 weeks (n=79) and >12 weeks (n=100), 5-year survival was 4%, 6%, and 8%, respectively (p=0.6). To conclude, in our experience and in contrast to other studies, prolonged overall treatment times in radiation therapy alone for inoperable NSCLC had no negative impact on long-term survival. It is hypothesized that accelerated tumor cell repopulation is absent in a significant number of these patients with the time-factor playing no apparent role for outcome of treatment. (orig.)

Fault Diagnosis from Raw Sensor Data Using Deep Neural Networks Considering Temporal Coherence.

Science.gov (United States)

Zhang, Ran; Peng, Zhen; Wu, Lifeng; Yao, Beibei; Guan, Yong

2017-03-09

Intelligent condition monitoring and fault diagnosis by analyzing the sensor data can assure the safety of machinery. Conventional fault diagnosis and classification methods usually implement pretreatments to decrease noise and extract some time domain or frequency domain features from raw time series sensor data. Then, some classifiers are utilized to make diagnosis. However, these conventional fault diagnosis approaches suffer from the expertise of feature selection and they do not consider the temporal coherence of time series data. This paper proposes a fault diagnosis model based on Deep Neural Networks (DNN). The model can directly recognize raw time series sensor data without feature selection and signal processing. It also takes advantage of the temporal coherence of the data. Firstly, raw time series training data collected by sensors are used to train the DNN until the cost function of DNN gets the minimal value; Secondly, test data are used to test the classification accuracy of the DNN on local time series data. Finally, fault diagnosis considering temporal coherence with former time series data is implemented. Experimental results show that the classification accuracy of bearing faults can get 100%. The proposed fault diagnosis approach is effective in recognizing the type of bearing faults.

Prolonged Remission in Neuromyelitis Optica Following Cessation of Rituximab Treatment.

Science.gov (United States)

Weinfurtner, Kelley; Graves, Jennifer; Ness, Jayne; Krupp, Lauren; Milazzo, Maria; Waubant, Emmanuelle

2015-09-01

Neuromyelitis optica is an autoimmune disease characterized by acute episodes of transverse myelitis and optic neuritis. Several small, open-label studies suggest rituximab, a monoclonal antibody against CD20, prevents relapses in neuromyelitis optica; however, there is little consensus on timing or duration of treatment. Here we report four patients with severe relapsing neuromyelitis optica who were stabilized on rituximab and, after discontinuing treatment, continued to experience prolonged remission of their disease. Remission ranged from 4.5 to 10.5 years total, including 3 to 9 years off all therapies. The patients had sustained clinical responses despite normal B-lymphocyte levels and, in at least 2 patients, continued seropositivity for aquaporin-4 antibodies. These cases suggest that rituximab may induce prolonged remission in certain neuromyelitis optica patients, and they highlight the need for further elucidation of rituximab's mechanism in neuromyelitis optica. © The Author(s) 2014.

Atraumatic femoral neck fracture secondary to prolonged lactation induced osteomalacia

Directory of Open Access Journals (Sweden)

Dhammapal Sahebrao Bhamare

2013-01-01

Full Text Available Presenting a case of atraumatic fracture neck femur secondary to 2 years of prolonged lactation. A 26-year-old lactating mother presented with pain in left hip from last 12 months. She was apparently alright before and during pregnancy. Plain radiograph showed a complete undisplaced fracture of femoral neck. Osteomalacia was diagnosed by radiological and serological investigations. The fracture was fixed using AO type cannulated cancellous screws. The fracture showed good clinical and radiological union at 3 months. Literature review shows that this is a first case of atraumatic fracture of neck femur due to prolonged lactational osteomalacia. It showed that even apparently healthy Indians are susceptible to osteomalacia, more so during pregnancy and lactation and can be presented as atraumatic fracture. Although considered relatively stable, a compression type incomplete fracture neck femur may progress to a complete fracture if not treated in time.

Brain mapping after prolonged cycling and during recovery in the heat.

Science.gov (United States)

De Pauw, Kevin; Roelands, Bart; Marusic, Uros; Tellez, Helio Fernandez; Knaepen, Kristel; Meeusen, Romain

2013-11-01

The aim of this study was to determine the effect of prolonged intensive cycling and postexercise recovery in the heat on brain sources of altered brain oscillations. After a max test and familiarization trial, nine trained male subjects (23 ± 3 yr; maximal oxygen uptake = 62.1 ± 5.3 ml·min(-1)·kg(-1)) performed three experimental trials in the heat (30°C; relative humidity 43.7 ± 5.6%). Each trial consisted of two exercise tasks separated by 1 h. The first was a 60-min constant-load trial, followed by a 30-min simulated time trial (TT1). The second comprised a 12-min simulated time trial (TT2). After TT1, active recovery (AR), passive rest (PR), or cold water immersion (CWI) was applied for 15 min. Electroencephalography was measured at baseline and during postexercise recovery. Standardized low-resolution brain electromagnetic tomography was applied to accurately pinpoint and localize altered electrical neuronal activity. After CWI, PR and AR subjects completed TT2 in 761 ± 42, 791 ± 76, and 794 ± 62 s, respectively. A prolonged intensive cycling performance in the heat decreased β activity across the whole brain. Postexercise AR and PR elicited no significant electrocortical differences, whereas CWI induced significantly increased β3 activity in Brodmann areas (BA) 13 (posterior margin of insular cortex) and BA 40 (supramarginal gyrus). Self-paced prolonged exercise in the heat seems to decrease β activity, hence representing decreased arousal. Postexercise CWI increased β3 activity at BA 13 and 40, brain areas involved in somatosensory information processing.

Manipulating quantum coherence of charge states in interacting double-dot Aharonov–Bohm interferometers

Science.gov (United States)

Jin, Jinshuang; Wang, Shikuan; Zhou, Jiahuan; Zhang, Wei-Min; Yan, YiJing

2018-04-01

We investigate the dynamics of charge-state coherence in a degenerate double-dot Aharonov–Bohm interferometer with finite inter-dot Coulomb interactions. The quantum coherence of the charge states is found to be sensitive to the transport setup configurations, involving both the single-electron impurity channels and the Coulomb-assisted ones. We numerically demonstrate the emergence of a complete coherence between the two charge states, with the relative phase being continuously controllable through the magnetic flux. Interestingly, a fully coherent charge qubit arises at the double-dots electron pair tunneling resonance condition, where the chemical potential of one electrode is tuned at the center between a single-electron impurity channel and the related Coulomb-assisted channel. This pure quantum state of charge qubit could be experimentally realized at the current–voltage characteristic turnover position, where differential conductance sign changes. We further elaborate the underlying mechanism for both the real-time and the stationary charge-states coherence in the double-dot systems of study.

Fermionic covariant prolongation structure theory for supernonlinear evolution equation

International Nuclear Information System (INIS)

Cheng Jipeng; Wang Shikun; Wu Ke; Zhao Weizhong

2010-01-01

We investigate the superprincipal bundle and its associated superbundle. The super(nonlinear)connection on the superfiber bundle is constructed. Then by means of the connection theory, we establish the fermionic covariant prolongation structure theory of the supernonlinear evolution equation. In this geometry theory, the fermionic covariant fundamental equations determining the prolongation structure are presented. As an example, the supernonlinear Schroedinger equation is analyzed in the framework of this fermionic covariant prolongation structure theory. We obtain its Lax pairs and Baecklund transformation.

Coherent photoluminescence excitation spectroscopy of semicrystalline polymeric semiconductors

Science.gov (United States)

Silva, Carlos; Grégoire, Pascal; Thouin, Félix

In polymeric semiconductors, the competition between through-bond (intrachain) and through-space (interchain) electronic coupling determines two-dimensional spatial coherence of excitons. The balance of intra- and interchain excitonic coupling depends very sensitively on solid-state microstructure of the polymer film (polycrystalline, semicrystalline with amorphous domains, etc.). Regioregular poly(3-hexylthiophene) has emerged as a model material because its photoluminescence (PL) spectral lineshape reveals intricate information on the magnitude of excitonic coupling, the extent of energetic disorder, and on the extent to which the disordered energy landscape is correlated. I discuss implementation of coherent two-dimensional electronic spectroscopy. We identify cross peaks between 0-0 and 0-1 excitation peaks, and we measure their time evolution, which we interpret within the context of a hybrid HJ aggregate model. By measurement of the homogeneous linewidth in diverse polymer microstructures, we address the nature of optical transitions within such hynbrid aggregate model. These depend strongly on sample processing, and I discuss the relationship between microstructure, steady-state absorption and PL spectral lineshape, and 2D coherent PL excitation spectral lineshapes.

The quantum coherence of disordered dipolar bosonic gas

International Nuclear Information System (INIS)

Wang Jiguo; Zhang Aixia; Tang Rongan; Gao Jimin; Xue Jukui

2013-01-01

We investigate the coherence of correlated dipolar gas in the presence of disorder within a three-site Bose–Hubbard model. We show that the interplay between the on-site interaction, the inter-site dipole–dipole interactions (DDI) and the disorder exhibits new and interesting coherence characters that cannot take place in a non-dipolar system. The ratio between the on-site interaction and DDI plays a dominant role in the phase coherence. The resonance character of the coherence against both disorder and interactions emerges. DDI can enhance the coherence at certain values of the disorder and on-site interaction. In the coherence region, the enhancement of the coherence by disorder in a dipolar system is more significant than that in a non-dipolar system. In particular, the on-site interaction and DDI together can enhance the coherence even in the clean dipolar system (i.e. a dipolar system without disorder). However, without the on-site interaction, disorder, DDI or both together suppress the coherence. Furthermore, the relationship between the coherence and the energy gap and the compressibility of the system is also discussed. (paper)

Inflammation and prolonged QT time: results from the Cardiovascular Disease, Living and Ageing in Halle (CARLA study.

Directory of Open Access Journals (Sweden)

Daniel Medenwald

Full Text Available Previous research found an association of CRP with QT time in population based samples. Even more, there is evidence of a substantial involvement of the tumor necrosis factor-alpha system in the pathophysiology of cardiac arrhythmia, while the role of Interleukin 6 remains inconclusive.To determine the association between inflammation with an abnormally prolonged QT-time (APQT in men and women of the elderly general population.Data descend from the baseline examination of the prospective, population-based Cardiovascular Disease, Living and Ageing in Halle (CARLA Study. After exclusion of subjects with atrial fibrillation and missing ECG recording the final study cohort consisted of 919 men and 797 women. Blood parameters of inflammation were the soluble TNF-Receptor 1 (sTNF-R1, the high-sensitive C-reactive protein (hsCRP, and Interleukin 6 (IL-6. In accordance with major cardiologic societies we defined an APQT above a QT time of 460 ms in women and 450 ms in men. Effect sizes and the corresponding 95% confidence intervals (CI were estimated by performing multiple linear and logistic regression analyses including the analysis of sex differences by interaction terms.After covariate adjustment we found an odds ratio (OR of 1.89 (95% CI: 1.13, 3.17 per 1000 pg/mL increase of sTNF-R1 in women, and 0.74 (95% CI: 0.48, 1.15 in men. In the covariate adjusted linear regression sTNF-R1 was again positively associated with QT time in women (5.75 ms per 1000 pg/mL, 95% CI: 1.32, 10.18, but not in men. Taking possible confounders into account IL-6 and hsCRP were not significantly related to APQT in both sexes.Our findings from cross-sectional analyses give evidence for an involvement of TNF-alpha in the pathology of APQT in women.

Simulation of coherent interactions between Rydberg atoms

International Nuclear Information System (INIS)

Robicheaux, F.; Hernandez, J.V.; Topcu, T.; Noordam, L.D.

2004-01-01

The results of a theoretical investigation of the coherent interaction between many Rydberg atoms are reported. The atoms are assumed to move very little during the time range we investigate. We describe the basic interaction between atoms and show that (contrary to previous theoretical studies) the interaction between the atoms can be coherent. The band structure for a perfect lattice of atoms and the density of states for an amorphous distribution of atoms are presented. We also give results for when the atoms are roughly positioned in a lattice. Finally, we performed detailed calculations to understand when the Rydberg interactions are too strong for an essential states type of approximation. The relevance of our results to previous measurements in a Rydberg gas and to possible future experiments is discussed

Portable atomic frequency standard based on coherent population trapping

Science.gov (United States)

Shi, Fan; Yang, Renfu; Nian, Feng; Zhang, Zhenwei; Cui, Yongshun; Zhao, Huan; Wang, Nuanrang; Feng, Keming

2015-05-01

In this work, a portable atomic frequency standard based on coherent population trapping is designed and demonstrated. To achieve a portable prototype, in the system, a single transverse mode 795nm VCSEL modulated by a 3.4GHz RF source is used as a pump laser which generates coherent light fields. The pump beams pass through a vapor cell containing atom gas and buffer gas. This vapor cell is surrounded by a magnetic shield and placed inside a solenoid which applies a longitudinal magnetic field to lift the Zeeman energy levels' degeneracy and to separate the resonance signal, which has no first-order magnetic field dependence, from the field-dependent resonances. The electrical control system comprises two control loops. The first one locks the laser wavelength to the minimum of the absorption spectrum; the second one locks the modulation frequency and output standard frequency. Furthermore, we designed the micro physical package and realized the locking of a coherent population trapping atomic frequency standard portable prototype successfully. The short-term frequency stability of the whole system is measured to be 6×10-11 for averaging times of 1s, and reaches 5×10-12 at an averaging time of 1000s.

Population coherent control of Rydberg potassium atom via adiabatic passage

International Nuclear Information System (INIS)

Jiang Li-Juan; Zhang Xian-Zhou; Jia Guang-Rui; Zhang Yong-Hui; Xia Li-Hua

2013-01-01

The time-dependent multilevel approach (TDMA) and B-spline expansion technique are used to study the coherent population transfer between the quantum states of a potassium atom by a single frequency-chirped microwave pulse. The Rydberg potassium atom energy levels of n = 6–15, l = 0–5 states in zero field are calculated and the results are in good agreement with other theoretical values. The time evolutions of the population transfer of the six states from n = 70 to n = 75 in different microwave fields are obtained. The results show that the coherent control of the population transfer from the lower states to the higher ones can be accomplished by optimizing the microwave pulse parameters. (atomic and molecular physics)

Prolonged Intermittent Renal Replacement Therapy.

Science.gov (United States)

Edrees, Fahad; Li, Tingting; Vijayan, Anitha

2016-05-01

Prolonged intermittent renal replacement therapy (PIRRT) is becoming an increasingly popular alternative to continuous renal replacement therapy in critically ill patients with acute kidney injury. There are significant practice variations in the provision of PIRRT across institutions, with respect to prescription, technology, and delivery of therapy. Clinical trials have generally demonstrated that PIRRT is non-inferior to continuous renal replacement therapy regarding patient outcomes. PIRRT offers cost-effective renal replacement therapy along with other advantages such as early patient mobilization and decreased nursing time. However, due to lack of standardization of the procedure, PIRRT still poses significant challenges, especially pertaining to appropriate drug dosing. Future guidelines and clinical trials should work toward developing consensus definitions for PIRRT and ensure optimal delivery of therapy. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Electron beam instrumentation techniques using coherent radiation

International Nuclear Information System (INIS)

Wang, D.X.

1997-01-01

Much progress has been made on coherent radiation research since coherent synchrotron radiation was first observed in 1989. The use of coherent radiation as a bunch length diagnostic tool has been studied by several groups. In this paper, brief introductions to coherent radiation and far-infrared measurement are given, the progress and status of their beam diagnostic application are reviewed, different techniques are described, and their advantages and limitations are discussed

Some remarks on quantum coherence theory

International Nuclear Information System (INIS)

Burzynski, A.

1982-01-01

This paper is devoted to the basic topics connected with coherence in quantum mechanics and quantum theory of radiation. In particular the formalism of the normal ordered coherence functions in cases of one and many degrees of freedom is described in detail. A few examples illustrate the analysis of the coherence properties of the various quantum states of the field of radiation. (author)

Manipulation of Zeeman coherence in solids at room temperature: Ramsey interference in the coherent-population-trapping spectrum of ruby

International Nuclear Information System (INIS)

Kolesov, Roman; Scully, Marlan O.; Kocharovskaya, Olga

2006-01-01

Coherent population trapping (CPT) in a three-level atomic medium pumped by two subsequent short optical pulses is considered under the condition of negligible population decay from the excited optical state. It is shown that the amount of atomic population transferred to the excited state by the combined action of the pulses strongly depends on the phase of the ground-state coherence excited by the first pulse at the arrival time of the second pulse. Oscillatory behavior of optical excitation efficiency on the time delay between the pulses is predicted. It is also shown that saturating optical pulses can produce population inversion in a resonantly pumped quasi-two-level system. A class of solid materials in which the predicted phenomena can be observed at room temperature is found. It includes some rare-earth and transition-metal doped dielectric crystals where Orbach relaxation between ground-state Zeeman states is suppressed: ruby, alexandrite, and several others. On the basis of the theoretical predictions, experimental observation of Ramsey fringes in CPT spectrum of ruby is reported

Optical Coherence Tomography

DEFF Research Database (Denmark)

Mogensen, Mette; Themstrup, Lotte; Banzhaf, Christina

2014-01-01

Optical coherence tomography (OCT) has developed rapidly since its first realisation in medicine and is currently an emerging technology in the diagnosis of skin disease. OCT is an interferometric technique that detects reflected and backscattered light from tissue and is often described as the o......Optical coherence tomography (OCT) has developed rapidly since its first realisation in medicine and is currently an emerging technology in the diagnosis of skin disease. OCT is an interferometric technique that detects reflected and backscattered light from tissue and is often described...

Coherence of light. 2. ed.

International Nuclear Information System (INIS)

Perina, J.

1985-01-01

This book puts the theory of coherence of light on a rigorous mathematical footing. It deals with the classical and quantum theories and with their inter-relationships, including many results from the author's own research. Particular attention is paid to the detection of optical fields, using the correlation functions, photocount statistics and coherent state. Radiometry with light fields of arbitrary states of coherence is discussed and the coherent state methods are demonstrated by photon statistics of radiation in random and nonlinear media, using the Heisenberg-Langevin and Fokker-Planck approaches to the interaction of radiation with matter. Many experimental and theoretical results are compared. A full list of references to theoretical and experimental literature is provided. The book is intended for researchers and postgraduate students in the fields of quantum optics, quantum electronics, statistical optics, nonlinear optics, optical communication and optoelectronics. (Auth.)

Perturbative coherence in field theory

International Nuclear Information System (INIS)

Aldrovandi, R.; Kraenkel, R.A.

1987-01-01

A general condition for coherent quantization by perturbative methods is given, because the basic field equations of a fild theory are not always derivable from a Lagrangian. It's seen that non-lagrangian models way have well defined vertices, provided they satisfy what they call the 'coherence condition', which is less stringent than the condition for the existence of a Lagrangian. They note that Lagrangian theories are perturbatively coherent, in the sense that they have well defined vertices, and that they satisfy automatically that condition. (G.D.F.) [pt

Models of coherent exciton condensation

International Nuclear Information System (INIS)

Littlewood, P B; Eastham, P R; Keeling, J M J; Marchetti, F M; Simons, B D; Szymanska, M H

2004-01-01

That excitons in solids might condense into a phase-coherent ground state was proposed about 40 years ago, and has been attracting experimental and theoretical attention ever since. Although experimental confirmation has been hard to come by, the concepts released by this phenomenon have been widely influential. This tutorial review discusses general aspects of the theory of exciton and polariton condensates, focusing on the reasons for coherence in the ground state wavefunction, the BCS to Bose crossover(s) for excitons and for polaritons, and the relationship of the coherent condensates to standard lasers

Models of coherent exciton condensation

Energy Technology Data Exchange (ETDEWEB)

Littlewood, P B [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Eastham, P R [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Keeling, J M J [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Marchetti, F M [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Simons, B D [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Szymanska, M H [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom)

2004-09-08

That excitons in solids might condense into a phase-coherent ground state was proposed about 40 years ago, and has been attracting experimental and theoretical attention ever since. Although experimental confirmation has been hard to come by, the concepts released by this phenomenon have been widely influential. This tutorial review discusses general aspects of the theory of exciton and polariton condensates, focusing on the reasons for coherence in the ground state wavefunction, the BCS to Bose crossover(s) for excitons and for polaritons, and the relationship of the coherent condensates to standard lasers.

Optimally cloned binary coherent states

Science.gov (United States)

Müller, C. R.; Leuchs, G.; Marquardt, Ch.; Andersen, U. L.

2017-10-01

Binary coherent state alphabets can be represented in a two-dimensional Hilbert space. We capitalize this formal connection between the otherwise distinct domains of qubits and continuous variable states to map binary phase-shift keyed coherent states onto the Bloch sphere and to derive their quantum-optimal clones. We analyze the Wigner function and the cumulants of the clones, and we conclude that optimal cloning of binary coherent states requires a nonlinearity above second order. We propose several practical and near-optimal cloning schemes and compare their cloning fidelity to the optimal cloner.

Interference due to coherence swapping

Indian Academy of Sciences (India)

particle is, its interaction with the beam splitter does not reveal this information .... If one shines a strong linearly polarised monochromatic laser beam, or a quasi .... to be a hindrance to coherence, can be suitably designed to create coherence.

Text Coherence in Translation

Science.gov (United States)

Zheng, Yanping

2009-01-01

In the thesis a coherent text is defined as a continuity of senses of the outcome of combining concepts and relations into a network composed of knowledge space centered around main topics. And the author maintains that in order to obtain the coherence of a target language text from a source text during the process of translation, a translator can…

Dynamics of quantum correlation and coherence for two atoms coupled with a bath of fluctuating massless scalar field

Energy Technology Data Exchange (ETDEWEB)

Huang, Zhiming, E-mail: 465609785@qq.com [School of Economics and Management, Wuyi University, Jiangmen 529020 (China); Situ, Haozhen, E-mail: situhaozhen@gmail.com [College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642 (China)

2017-02-15

In this article, the dynamics of quantum correlation and coherence for two atoms interacting with a bath of fluctuating massless scalar field in the Minkowski vacuum is investigated. We firstly derive the master equation that describes the system evolution with initial Bell-diagonal state. Then we discuss the system evolution for three cases of different initial states: non-zero correlation separable state, maximally entangled state and zero correlation state. For non-zero correlation initial separable state, quantum correlation and coherence can be protected from vacuum fluctuations during long time evolution when the separation between the two atoms is relatively small. For maximally entangled initial state, quantum correlation and coherence overall decrease with evolution time. However, for the zero correlation initial state, quantum correlation and coherence are firstly generated and then drop with evolution time; when separation is sufficiently small, they can survive from vacuum fluctuations. For three cases, quantum correlation and coherence first undergo decline and then fluctuate to relatively stable values with the increasing distance between the two atoms. Specially, for the case of zero correlation initial state, quantum correlation and coherence occur periodically revival at fixed zero points and revival amplitude declines gradually with increasing separation of two atoms.

Dynamics of quantum correlation and coherence for two atoms coupled with a bath of fluctuating massless scalar field

International Nuclear Information System (INIS)

Huang, Zhiming; Situ, Haozhen

2017-01-01

In this article, the dynamics of quantum correlation and coherence for two atoms interacting with a bath of fluctuating massless scalar field in the Minkowski vacuum is investigated. We firstly derive the master equation that describes the system evolution with initial Bell-diagonal state. Then we discuss the system evolution for three cases of different initial states: non-zero correlation separable state, maximally entangled state and zero correlation state. For non-zero correlation initial separable state, quantum correlation and coherence can be protected from vacuum fluctuations during long time evolution when the separation between the two atoms is relatively small. For maximally entangled initial state, quantum correlation and coherence overall decrease with evolution time. However, for the zero correlation initial state, quantum correlation and coherence are firstly generated and then drop with evolution time; when separation is sufficiently small, they can survive from vacuum fluctuations. For three cases, quantum correlation and coherence first undergo decline and then fluctuate to relatively stable values with the increasing distance between the two atoms. Specially, for the case of zero correlation initial state, quantum correlation and coherence occur periodically revival at fixed zero points and revival amplitude declines gradually with increasing separation of two atoms.

Coherent states and covariant semi-spectral measures

International Nuclear Information System (INIS)

Scutaru, H.

1976-01-01

The close connection between Mackey's theory of imprimitivity systems and the so called generalized coherent states introduced by Perelomov is established. Coherent states give a covariant description of the ''localization'' of a quantum system in the phase space in a similar way as the imprimitivity systems give a covariant description of the localization of a quantum system in the configuration space. The observation that for any system of coherent states one can define a covariant semi-spectral measure made possible a rigurous formulation of this idea. A generalization of the notion of coherent states is given. Covariant semi-spectral measures associated with systems of coherent states are defined and characterized. Necessary and sufficient conditions for a unitary representation of a Lie group to be i) a subrepresentation of an induced one and ii) a representation with coherent states are given (author)

[Evaluation of diabetic microangiopathy using optical coherence tomography angiography].

Science.gov (United States)

Czakó, Cecília; Sándor, Gábor László; Ecsedy, Mónika; Szepessy, Zsuzsanna; Borbándy, Ágnes; Resch, Miklós; Papp, András; Récsán, Zsuzsa; Horváth, Hajnalka; Nagy, Zoltán Zsolt; Kovács, Illés

2018-02-01

Optical coherence tomography angiography is a non-invasive imaging technique that is able to visualize the different retinal vascular layers using motion contrast to detect blood flow without intravenous dye injection. This method might help to assess microangiopathy in diabetic retinopathy during screening and follow-up. To quantify retinal microvasculature alterations in both eyes of diabetic patients in relation to systemic risk factors using optical coherence tomography angiography. Both eyes of 36 diabetic patients and 45 individuals without diabetes were examined. Duration of diabetes, insulin therapy, blood pressure, HbA 1c , dyslipidemia, axial length and the presence of diabetic retinopathy were recorded. Retinal vessel density was measured by optical coherence tomography angiography. The effect of risk factors on vessel density and between-eye asymmetry was assessed using multivariable regression analysis. Vessel density was significantly lower and between-eye difference was significantly higher in diabetic patients compared to controls (pdiabetes duration (pdiabetic retinopathy compared to control subjects (pdiabetes compared to healthy subjects. By using optical coherence tomography angiography, the detection of these microvascular alterations is possible before clinically detectable diabetic retinopathy and might serve as a useful tool in both screening and timing of treatment. Orv Hetil. 2018; 159(8): 320-326.

Geometry of spin coherent states

Science.gov (United States)

Chryssomalakos, C.; Guzmán-González, E.; Serrano-Ensástiga, E.

2018-04-01

Spin states of maximal projection along some direction in space are called (spin) coherent, and are, in many respects, the ‘most classical’ available. For any spin s, the spin coherent states form a 2-sphere in the projective Hilbert space \

Optical Coherence Tomography for the Assessment of Coronary Atherosclerosis and Vessel Response after Stent Implantation

NARCIS (Netherlands)

N. Gonzalo (Nieves)

2010-01-01

textabstractOptical Coherence Tomography (OCT) is a light-based imaging modality that can provide in vivo high-resolution images of the coronary artery with a level of resolution (axial 10-20 µm) ten times higher than intravascular ultrasound. The technique, uses low-coherent near infrarred light

Spatio-temporal coherence of free-electron laser radiation in the extreme ultraviolet determined by a Michelson interferometer

Energy Technology Data Exchange (ETDEWEB)

Hilbert, V.; Rödel, C.; Zastrau, U., E-mail: ulf.zastrau@uni-jena.de [Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena (Germany); Brenner, G.; Düsterer, S.; Dziarzhytski, S.; Harmand, M.; Przystawik, A.; Redlin, H.; Toleikis, S. [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Döppner, T.; Ma, T. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Fletcher, L. [Department of Physics, University of California, Berkeley, California 94720 (United States); Förster, E. [Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena (Germany); Helmholtz-Institut Jena, Fröbelstieg 3, 07743 Jena (Germany); Glenzer, S. H.; Lee, H. J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Hartley, N. J. [Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Kazak, L.; Komar, D.; Skruszewicz, S. [Institut für Physik, Universität Rostock, 18051 Rostock (Germany); and others

2014-09-08

A key feature of extreme ultraviolet (XUV) radiation from free-electron lasers (FELs) is its spatial and temporal coherence. We measured the spatio-temporal coherence properties of monochromatized FEL pulses at 13.5 nm using a Michelson interferometer. A temporal coherence time of (59±8) fs has been determined, which is in good agreement with the spectral bandwidth given by the monochromator. Moreover, the spatial coherence in vertical direction amounts to about 15% of the beam diameter and about 12% in horizontal direction. The feasibility of measuring spatio-temporal coherence properties of XUV FEL radiation using interferometric techniques advances machine operation and experimental studies significantly.

A detailed description of the short-term musculoskeletal and cognitive effects of prolonged standing for office computer work.

Science.gov (United States)

Baker, Richelle; Coenen, Pieter; Howie, Erin; Lee, Jeremy; Williamson, Ann; Straker, Leon

2018-07-01

Due to concerns about excessive sedentary exposure for office workers, alternate work positions such as standing are being trialled. However, prolonged standing may have health and productivity impacts, which this study assessed. Twenty adult participants undertook two hours of laboratory-based standing computer work to investigate changes in discomfort and cognitive function, along with muscle fatigue, movement, lower limb swelling and mental state. Over time, discomfort increased in all body areas (total body IRR [95% confidence interval]: 1.47[1.36-1.59]). Sustained attention reaction time (β = 18.25[8.00-28.51]) deteriorated, while creative problem solving improved (β = 0.89[0.29-1.49]). There was no change in erector spinae, rectus femoris, biceps femoris or tibialis anterior muscle fatigue; low back angle changed towards less  lordosis, pelvis movement increased, lower limb swelling increased and mental state decreased. Body discomfort was positively correlated with mental state. The observed changes suggest replacing office work sitting with standing should be done with caution. Practitioner Summary: Standing is being used to replace sitting by office workers; however, there are health risks associated with prolonged standing. In a laboratory study involving 2 h prolonged standing discomfort increased (all body areas), reaction time and mental state deteriorated while creative problem-solving improved. Prolonged standing should be undertaken with caution.

Dynamics of coherent states in regular and chaotic regimes of the non-integrable Dicke model

Science.gov (United States)

Lerma-Hernández, S.; Chávez-Carlos, J.; Bastarrachea-Magnani, M. A.; López-del-Carpio, B.; Hirsch, J. G.

2018-04-01

The quantum dynamics of initial coherent states is studied in the Dicke model and correlated with the dynamics, regular or chaotic, of their classical limit. Analytical expressions for the survival probability, i.e. the probability of finding the system in its initial state at time t, are provided in the regular regions of the model. The results for regular regimes are compared with those of the chaotic ones. It is found that initial coherent states in regular regions have a much longer equilibration time than those located in chaotic regions. The properties of the distributions for the initial coherent states in the Hamiltonian eigenbasis are also studied. It is found that for regular states the components with no negligible contribution are organized in sequences of energy levels distributed according to Gaussian functions. In the case of chaotic coherent states, the energy components do not have a simple structure and the number of participating energy levels is larger than in the regular cases.

Recurrence of the excited states of nuclei and time coherency of the de Broglie wave in 16O+n resonances

International Nuclear Information System (INIS)

Ohkubo, Makio

2003-01-01

From the requirement of the time periodicity of a (quasi) stable state, frequencies of the normal modes, which compose the state, are commensurable (integer ratios) with each other, and the excitation energies E x are written as a sum of inverse integers. We propose an expression: E x = GΣ1/n, where n = integers and G = 34.5 MeV. Recurrence time is defined as LCM(n j ) x τ o , where τ 0 = 2πℎ/G = 1.20 x 10 -22 s. LCM vs. E x are illustrated for all possible n j of 2 and 3 normal modes. In 16 O +n resonances, integer ratios are found between the recurrence frequencies of 17 O and the de Broglie wave frequencies of incident neutron, meaning time coherency between them. A simple branch pattern is found in 16 O +n resonance levels. (author)

Long lived coherence in self-assembled quantum dots

DEFF Research Database (Denmark)

Birkedal, Dan; Leosson, Kristjan; Hvam, Jørn Märcher

2001-01-01

We report measurements of ultralong coherence in self-assembled quantum dots. Transient four-wave mixing experiments at 5 K show an average dephasing time of 372 ps, corresponding to a homogeneous linewidth of 3.5 mu eV, which is significantly smaller than the linewidth observed in single...

Reduction of coherence of the human brain electric potentials

Science.gov (United States)

Novik, Oleg; Smirnov, Fedor

Plenty of technological processes are known to be damaged by magnetic storms. But technology is controlled by men and their functional systems may be damaged as well. We are going to consider the electro-neurophysiological aspect of the general problem: men surrounded by physical fields including ones of cosmic origination. Magnetic storms’ influence had been observed for a group of 13 students (practically healthy girls and boys from 18 to 23 years old, Moscow). To control the main functional systems of the examinees, their electroencephalograms (EEG) were being registered along with electrocardiograms, respiratory rhythms, arterial blood pressure and other characteristics during a year. All of these characteristics, save for the EEG, were within the normal range for all of the examinees during measurements. According to the EEG investigations by implementation of the computer proof-reading test in absence of magnetic storms, the values of the coherence function of time series of the theta-rhythm oscillations (f = 4 - 7.9 Hz, A = 20 μV) of electric potentials of the frontal-polar and occipital areas of the head belong to the interval [0.3, 0.8] for all of the students under investigation. (As the proof-reading test, it was necessary to choose given symbols from a random sequence of ones demonstrated at a monitor and to enter the number of the symbols discovered in a computer. Everyone was known that the time for determination of symbols is unlimited. On the other hand, nobody was known that the EEG and other registrations mentioned are connected with electromagnetic geophysical researches and geomagnetic storms). Let us formulate the main result: by implementation of the same test during a magnetic storm, 5 ≤ K ≤ 6, or no later then 24 hours after its beginning (different types of moderate magnetic storms occurred, the data of IZMIRAN were used), the values of the theta-rhythm frontal - occipital coherence function of all of the students of the group under

Coherent light microscopy

CERN Document Server

Ferraro, Pietro; Zalevsky, Zeev

2011-01-01

This book deals with the latest achievements in the field of optical coherent microscopy. While many other books exist on microscopy and imaging, this book provides a unique resource dedicated solely to this subject. Similarly, many books describe applications of holography, interferometry and speckle to metrology but do not focus on their use for microscopy. The coherent light microscopy reference provided here does not focus on the experimental mechanics of such techniques but instead is meant to provide a users manual to illustrate the strengths and capabilities of developing techniques. Th

Entropy coherent and entropy convex measures of risk

NARCIS (Netherlands)

Laeven, R.J.A.; Stadje, M.

2013-01-01

We introduce two subclasses of convex measures of risk, referred to as entropy coherent and entropy convex measures of risk. Entropy coherent and entropy convex measures of risk are special cases of φ-coherent and φ-convex measures of risk. Contrary to the classical use of coherent and convex

An unusual case of prolonged post-endoscopic retrograde cholangiopancreatography jaundice.

Science.gov (United States)

Tziatzios, Georgios; Gkolfakis, Paraskevas; Papanikolaou, Ioannis S; Dimitriadis, George; Triantafyllou, Konstantinos

2016-04-01

Despite the effectiveness of endoscopic retrograde cholangiopancreatography (ERCP) for the treatment of choledocholithiasis, various complications have been described. We herein report the first case of prolonged post-ERCP jaundice due to toxicity of the contrast agent Iobitridol (®XENETIX, Guerbet, Roissy CdG Cedex, France) in a patient who underwent ERCP with sphincterectomy and common bile duct stone removal. While clinical improvement and normalization of aminotransferases and cholestatic enzymes after the procedure, an unexplained increase of direct bilirubin was noticed. A second ERCP was performed one week later, excluding possible remaining choledocholithiasis. Nevertheless, serum direct bilirubin increased further up to 15 mg/dL. Other potential causes of direct hyperbilirubinemia were ruled out and patient's liver biopsy was compatible with drug-induced liver toxicity. Additionally, the cause-result time connection between the use of Iobitridol and bilirubin increase indicated the possibility of a toxic effect related to the repeated use of the particular contrast agent. Iobitridol, a contrast agent, can induce prolonged direct hyperbilirubinemia.

Evolution of perceived footwear comfort over a prolonged running session.

Science.gov (United States)

Hintzy, F; Cavagna, J; Horvais, N

2015-12-01

The purpose of this study was to investigate the subjective perception of overall footwear comfort over a prolonged running session. Ten runners performed two similar sessions consisting of a 13-km trail run (5 laps of 2.6 km) as fast as possible. The overall footwear comfort was evaluated before running and at the end of each lap with a 150-mm visual analogic scale, as well as speed, heart rate and rate of perceived exertion. The results showed that both overall footwear comfort and speed decreased consistently during the run session, and significantly after 44 min of running (i.e. the 3rd lap). It could be hypothesized that the deterioration of overall footwear comfort was explained by mechanical and energetical parameter changes with time and/or fatigue occurring at the whole body, foot and footwear levels. These results justify the use of a prolonged running test for running footwear comfort evaluation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Real-time processing for full-range Fourier-domain optical-coherence tomography with zero-filling interpolation using multiple graphic processing units.

Science.gov (United States)

Watanabe, Yuuki; Maeno, Seiya; Aoshima, Kenji; Hasegawa, Haruyuki; Koseki, Hitoshi

2010-09-01

The real-time display of full-range, 2048?axial pixelx1024?lateral pixel, Fourier-domain optical-coherence tomography (FD-OCT) images is demonstrated. The required speed was achieved by using dual graphic processing units (GPUs) with many stream processors to realize highly parallel processing. We used a zero-filling technique, including a forward Fourier transform, a zero padding to increase the axial data-array size to 8192, an inverse-Fourier transform back to the spectral domain, a linear interpolation from wavelength to wavenumber, a lateral Hilbert transform to obtain the complex spectrum, a Fourier transform to obtain the axial profiles, and a log scaling. The data-transfer time of the frame grabber was 15.73?ms, and the processing time, which includes the data transfer between the GPU memory and the host computer, was 14.75?ms, for a total time shorter than the 36.70?ms frame-interval time using a line-scan CCD camera operated at 27.9?kHz. That is, our OCT system achieved a processed-image display rate of 27.23 frames/s.

Implementation of Prolonged Exposure in the Army: Is Consultation Necessary for Effective Dissemination

Science.gov (United States)

2015-10-01

to hiring websites and local advertisements , and several candidates were identified. An initial part-time offer was made to Loreli Leos, LPC in July...2015). Prolonged exposure vs eye movement desensitization and reprocessing vs waiting list for posttraumatic stress disorder in patients with a

Management of prolonged pregnancy

International Nuclear Information System (INIS)

Iqbal, S.

2004-01-01

Objective: To compare two strategies for management of prolonged pregnancy (= or >294 days) i.e. induction (intervention) versus expectant management (non-intervention) and evaluate the associated feto-maternal risks. Subjects and Methods: One hundred cases of uncomplicated prolonged gestation were selected. The gestational age was confirmed by ultrasound in first trimester. One group (50 patients) was managed by intervention i.e. induction of labour (group A) and other group (50 patients) by non-intervention i.e. expectant management (group B). In group A intervention was done at 42 weeks. In expectant group, the methods of monitoring were fetal kick charting recorded daily by the patient, and ultrasound for amniotic fluid index. The biophysical profile score and NST (non stress test) were performed once a week till 42 weeks and then twice weekly. Results: The frequency of prolonged pregnancy was found to be 10.9%. There was no significant difference in the number of spontaneous vaginal deliveries between the two groups. The rate of LSCS (lower segment caesarean section) was higher in intervention group ( 30% versus 18% ). The neonatal depression at birth was more in group B ( 10% versus 4%) and at 5 minutes almost same between two groups (4% versus 2%). There were 11 cases of meconium aspiration syndrome, leading to one neonatal death. Among nine perinatal deaths two were neonatal deaths. Seven cases of intrauterine deaths in which antepartum deaths occurred because of non compliance of patients. No cause could be detected for the other three fetuses. Conclusion: There was increased LSCS rate in group A. However in expectant group B perinatal mortality was about twice more as compared to intervention group. Active early intervention at 42 weeks is warranted to reduce perinatal morbidity and mortality. (author)