Algorithm Indicating Moment of P-Wave Arrival Based on Second-Moment Characteristic
Directory of Open Access Journals (Sweden)
Jakub Sokolowski
2016-01-01
Full Text Available The moment of P-wave arrival can provide us with many information about the nature of a seismic event. Without adequate knowledge regarding the onset moment, many properties of the events related to location, polarization of P-wave, and so forth are impossible to receive. In order to save time required to indicate P-wave arrival moment manually, one can benefit from automatic picking algorithms. In this paper two algorithms based on a method finding a regime switch point are applied to seismic event data in order to find P-wave arrival time. The algorithms are based on signals transformed via a basic transform rather than on raw recordings. They involve partitioning the transformed signal into two separate series and fitting logarithm function to the first subset (which corresponds to pure noise and therefore it is considered stationary, exponent or power function to the second subset (which corresponds to nonstationary seismic event, and finding the point at which these functions best fit the statistic in terms of sum of squared errors. Effectiveness of the algorithms is tested on seismic data acquired from O/ZG “Rudna” underground copper ore mine with moments of P-wave arrival initially picked by broadly known STA/LTA algorithm and then corrected by seismic station specialists. The results of proposed algorithms are compared to those obtained using STA/LTA.
Towards routine determination of focal mechanisms obtained from first motion P-wave arrivals
Lentas, K.
2018-03-01
The Bulletin of the International Seismological Centre (ISC) contains information on earthquake mechanisms collected from many different sources including national and global agencies, resulting in a satisfactory coverage over a wide magnitude range (M ˜2-9). Nevertheless, there are still a vast number of earthquakes with no reported source mechanisms especially for magnitudes up to 5. This study investigates the possibility of calculating earthquake focal mechanisms in a routine and systematic way based on P-wave first motion polarities. Any available parametric data in the ISC database is being used, as well as auto-picked polarities from waveform data up to teleseismic epicentral distances (90°) for stations that are not reported to the ISC. The determination of the earthquake mechanisms is carried out with a modified version of the HASH algorithm that is compatible with a wide range of epicentral distances and takes into account the ellipsoids defined by the ISC location errors, and the Earth's structure uncertainties. Initially, benchmark tests for a set of ISC reviewed earthquakes (mb > 4.5) are carried out and the HASH mechanism classification scheme is used to define the mechanism quality. Focal mechanisms of quality A, B and C with an azimuthal gap up to 90° compare well to the benchmark mechanisms. Nevertheless, the majority of the obtained mechanisms fall into class D as a result of limited polarity data from stations in local/regional epicentral distances. Specifically, the computation of the minimum rotation angle between the obtained mechanisms and the benchmarks, reveals that 41 per cent of the examined earthquakes show rotation angles up to 35°. Finally, the current technique is applied to a small set of earthquakes from the reviewed ISC bulletin where 62 earthquakes, with no previously reported source mechanisms, are successfully obtained.
Kodera, Yuki
2018-01-01
Large earthquakes with long rupture durations emit P wave energy throughout the rupture period. Incorporating late-onset P waves into earthquake early warning (EEW) algorithms could contribute to robust predictions of strong ground motion. Here I describe a technique to detect in real time P waves from growing ruptures to improve the timeliness of an EEW algorithm based on seismic wavefield estimation. The proposed P wave detector, which employs a simple polarization analysis, successfully detected P waves from strong motion generation areas of the 2011 Mw 9.0 Tohoku-oki earthquake rupture. An analysis using 23 large (M ≥ 7) events from Japan confirmed that seismic intensity predictions based on the P wave detector significantly increased lead times without appreciably decreasing the prediction accuracy. P waves from growing ruptures, being one of the fastest carriers of information on ongoing rupture development, have the potential to improve the performance of EEW systems.
Improvement of a picking algorithm real-time P-wave detection by kurtosis
Ishida, H.; Yamada, M.
2016-12-01
Earthquake early warning (EEW) requires fast and accurate P-wave detection. The current EEW system in Japan uses the STA/LTAalgorithm (Allen, 1978) to detect P-wave arrival.However, some stations did not trigger during the 2011 Great Tohoku Earthquake due to the emergent onset. In addition, accuracy of the P-wave detection is very important: on August 1, 2016, the EEW issued a false alarm with M9 in Tokyo region due to a thunder noise.To solve these problems, we use a P-wave detection method using kurtosis statistics. It detects the change of statistic distribution of the waveform amplitude. This method was recently developed (Saragiotis et al., 2002) and used for off-line analysis such as making seismic catalogs. To apply this method for EEW, we need to remove an acausal calculation and enable a real-time processing. Here, we propose a real-time P-wave detection method using kurtosis statistics with a noise filter.To avoid false triggering by a noise, we incorporated a simple filter to classify seismic signal and noise. Following Kong et al. (2016), we used the interquartilerange and zero cross rate for the classification. The interquartile range is an amplitude measure that is equal to the middle 50% of amplitude in a certain time window. The zero cross rate is a simple frequency measure that counts the number of times that the signal crosses baseline zero. A discriminant function including these measures was constructed by the linear discriminant analysis.To test this kurtosis method, we used strong motion records for 62 earthquakes between April, 2005 and July, 2015, which recorded the seismic intensity greater equal to 6 lower in the JMA intensity scale. The records with hypocentral distance picks. It shows that the median error is 0.13 sec and 0.035 sec for STA/LTA and kurtosis method. The kurtosis method tends to be more sensitive to small changes in amplitude.Our approach will contribute to improve the accuracy of source location determination of
Equilibrium Arrival Times to Queues
DEFF Research Database (Denmark)
Breinbjerg, Jesper; Østerdal, Lars Peter
We consider a non-cooperative queueing environment where a finite number of customers independently choose when to arrive at a queueing system that opens at a given point in time and serves customers on a last-come first-serve preemptive-resume (LCFS-PR) basis. Each customer has a service time...... requirement which is identically and independently distributed according to some general probability distribution, and they want to complete service as early as possible while minimizing the time spent in the queue. In this setting, we establish the existence of an arrival time strategy that constitutes...... a symmetric (mixed) Nash equilibrium, and show that there is at most one symmetric equilibrium. We provide a numerical method to compute this equilibrium and demonstrate by a numerical example that the social effciency can be lower than the effciency induced by a similar queueing system that serves customers...
Energy Technology Data Exchange (ETDEWEB)
Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh
2007-07-06
In this volume (I), all P-wave measurements are presented that were performed in Borehole C4993 at the Waste Treatment Plant (WTP) with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver. P-wave measurements were performed over the depth range of 370 to 1400 ft, typically in 10-ft intervals. However, in some interbeds, 5-ft depth intervals were used, while below about 1200 ft, depth intervals of 20 ft were used. Compression (P) waves were generated by moving the base plate of T-Rex for a given number of cycles at a fixed frequency as discussed in Section 2. This process was repeated so that signal averaging in the time domain was performed using 3 to about 15 averages, with 5 averages typically used. In addition to the LBNL 3-D geophone, called the lower receiver herein, a 3-D geophone from Redpath Geophysics was fixed at a depth of 22 ft in Borehole C4993, and a 3-D geophone from the University of Texas was embedded near the borehole at about 1.5 ft below the ground surface. This volume is organized into 12 sections as follows: Section 1: Introduction, Section 2: Explanation of Terminology, Section 3: Vp Profile at Borehole C4993, Sections 4 to 6: Unfiltered P-wave records of lower vertical receiver, reaction mass, and reference receiver, Sections 7 to 9: Filtered P-wave signals of lower vertical receiver, reaction mass and reference receiver, Section 10: Expanded and filtered P-wave signals of lower vertical receiver, and Sections 11 and 12: Waterfall plots of unfiltered and filtered lower vertical receiver signals.
Energy Technology Data Exchange (ETDEWEB)
Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh
2007-06-06
In this volume (III), all P-wave measurements are presented that were performed in Borehole C4997 at the Waste Treatment Plant (WTP) with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver. P-wave measurements were performed over the depth range of 390 to 1220 ft, typically in 10-ft intervals. However, in some interbeds, 5-ft depth intervals were used. Compression (P) waves were generated by moving the base plate of T-Rex for a given number of cycles at a fixed frequency as discussed in Section 2. This process was repeated so that signal averaging in the time domain was performed using 3 to about 15 averages, with 5 averages typically used. In addition to the LBNL 3-D geophone, called the lower receiver herein, a 3-D geophone from Redpath Geophysics was fixed at a depth of 40 ft (later relocated to 27.5 ft due to visibility in borehole after rain) in Borehole C4997, and a 3-D geophone from the University of Texas was embedded near the borehole at about 1.5 ft below the ground surface. This volume is organized into 12 sections as follows: Section 1: Introduction, Section 2: Explanation of Terminology, Section 3: Vp Profile at Borehole C4997, Sections 4 to 6: Unfiltered P-wave records of lower vertical receiver, reaction mass, and reference receiver, Sections 7 to 9: Filtered P-wave signals of lower vertical receiver, reaction mass and reference receiver, Section 10: Expanded and filtered P-wave signals of lower vertical receiver, and Sections 11 and 12: Waterfall plots of unfiltered and filtered lower vertical receiver signals.
Energy Technology Data Exchange (ETDEWEB)
Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh
2007-07-06
In this volume (II), all P-wave measurements are presented that were performed in Borehole C4996 at the Waste Treatment Plant (WTP) with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver. P-wave measurements were performed over the depth range of 360 to 1400 ft, typically in 10-ft intervals. However, in some interbeds, 5-ft depth intervals were used, while below about 1180 ft, depth intervals of 20 ft were used. Compression (P) waves were generated by moving the base plate of T-Rex for a given number of cycles at a fixed frequency as discussed in Section 2. This process was repeated so that signal averaging in the time domain was performed using 3 to about 15 averages, with 5 averages typically used. In addition to the LBNL 3-D geophone, called the lower receiver herein, a 3-D geophone from Redpath Geophysics was fixed at a depth of 22 ft in Borehole C4996, and a 3-D geophone from the University of Texas was embedded near the borehole at about 1.5 ft below the ground surface. This volume is organized into 12 sections as follows: Section 1: Introduction, Section 2: Explanation of Terminology, Section 3: Vp Profile at Borehole C4996, Sections 4 to 6: Unfiltered P-wave records of lower vertical receiver, reaction mass, and reference receiver, Sections 7 to 9: Filtered P-wave signals of lower vertical receiver, reaction mass and reference receiver, Section 10: Expanded and filtered P-wave signals of lower vertical receiver, and Sections 11 and 12: Waterfall plots of unfiltered and filtered lower vertical receiver signals.
Fan, Wenyuan; Shearer, Peter M.
2018-04-01
Teleseismic records of the 2012 Mw 7.2 Sumatra earthquake contain prominent phases in the P wave train, arriving about 50 to 100 s after the direct P arrival. Azimuthal variations in these arrivals, together with back-projection analysis, led Fan and Shearer (https://doi.org/10.1002/2016GL067785) to conclude that they originated from early aftershock(s), located ˜150 km northeast of the mainshock and landward of the trench. However, recently, Yue et al. (https://doi.org/10.1002/2017GL073254) argued that the anomalous arrivals are more likely water reverberations from the mainshock, based mostly on empirical Green's function analysis of a M6 earthquake near the mainshock and a water phase synthetic test. Here we present detailed back-projection and waveform analyses of three M6 earthquakes within 100 km of the Mw 7.2 earthquake, including the empirical Green's function event analyzed in Yue et al. (https://doi.org/10.1002/2017GL073254). In addition, we examine the waveforms of three M5.5 reverse-faulting earthquakes close to the inferred early aftershock location in Fan and Shearer (https://doi.org/10.1002/2016GL067785). These results suggest that the reverberatory character of the anomalous arrivals in the mainshock coda is consistent with water reverberations, but the origin of this energy is more likely an early aftershock rather than delayed and displaced water reverberations from the mainshock.
Determination of P – wave arrival time of acoustic events
Directory of Open Access Journals (Sweden)
Matěj Petružálek
2010-10-01
Full Text Available The new approach to the P-wave arrival time determination based on acoustic emission data from loading experiments is tested.The algorithm used in this paper is built on the STA/LTA function computed by a convolution that speeds up the computation processvery much. The picking process makes use of shifting of temporary onset until certain conditions are fulfill and as a main decisioncriterion on the threshold exceeding of the STA/LTA derivation function is used. The P-wave onset time is determined in a selectedinterval that corresponds to the theoretical propagation of elastic wave in the rock sample. Results obtained by our algorithm werecorrelated with data acquired manually and a high order statistic software as well.
Scaling relation between earthquake magnitude and the departure time from P wave similar growth
Noda, Shunta; Ellsworth, William L.
2016-01-01
We introduce a new scaling relation between earthquake magnitude (M) and a characteristic of initial P wave displacement. By examining Japanese K-NET data averaged in bins partitioned by Mw and hypocentral distance, we demonstrate that the P wave displacement briefly displays similar growth at the onset of rupture and that the departure time (Tdp), which is defined as the time of departure from similarity of the absolute displacement after applying a band-pass filter, correlates with the final M in a range of 4.5 ≤ Mw ≤ 7. The scaling relation between Mw and Tdp implies that useful information on the final M can be derived while the event is still in progress because Tdp occurs before the completion of rupture. We conclude that the scaling relation is important not only for earthquake early warning but also for the source physics of earthquakes.
Study on the P-wave feature time course as early predictors of paroxysmal atrial fibrillation
International Nuclear Information System (INIS)
Martínez, Arturo; Alcaraz, Raúl; Rieta, José J
2012-01-01
Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice, increasing the risk of stroke and all-cause mortality. Its mechanisms are poorly understood, thus leading to different theories and controversial interpretation of its behavior. In this respect, it is unknown why AF is self-terminating in certain individuals, which is called paroxysmal AF (PAF), and not in others. Within the context of biomedical signal analysis, predicting the onset of PAF with a reasonable advance has been a clinical challenge in recent years. By predicting arrhythmia onset, the loss of normal sinus rhythm could be addressed by means of preventive treatments, thus minimizing risks for the patients and improving their quality of life. Traditionally, the study of PAF onset has been undertaken through a variety of features characterizing P-wave spatial diversity from the standard 12-lead electrocardiogram (ECG) or from signal-averaged ECGs. However, the variability of features from the P-wave time course before PAF onset has not been exploited yet. This work introduces a new alternative to assess time diversity of the P-wave features from single-lead ECG recordings. Furthermore, the method is able to assess the risk of arrhythmia 1 h before its onset, which is a relevant advance in order to provide clinically useful PAF risk predictors. Results were in agreement with the electrophysiological changes taking place in the atria. Hence, P-wave features presented an increasing variability as PAF onset approximates, thus suggesting intermittently disturbed conduction in the atrial tissue. In addition, high PAF risk prediction accuracy, greater than 90%, has been reached in the two considered scenarios, i.e. discrimination between healthy individuals and PAF patients and between patients far from PAF and close to PAF onset. Nonetheless, more long-term studies have to be analyzed and validated in future works. (paper)
Bennington, N. L.; Thurber, C. H.; Peng, Z.; Zhao, P.
2012-12-01
We present a 3D P-wave velocity (Vp) model of the Parkfield region that utilizes existing P-wave arrival time data, including fault zone head waves (FZHW), plus new data from direct wave secondary arrivals (DWSA). The first-arrival and DWSA travel times are obtained as the global and local minimum travel time paths, respectively. The inclusion of DWSA results in as much as a 10% increase in the across-fault velocity contrast for the Vp model at Parkfield relative to Thurber et al. (2006). Viewed along strike, three pronounced velocity contrast regions are observed: a pair of strong positive velocity contrasts (SW fast), one NW of the 1966 Parkfield hypocenter and the other SE of the 2004 Parkfield hypocenter, and a strong negative velocity contrast (NE fast) between the two hypocenters. The negative velocity contrast partially to entirely encompasses peak coseismic slip estimated in several slip models for the 2004 earthquake, suggesting that the negative velocity contrast played a part in defining the rupture patch of the 2004 Parkfield earthquake. We expand on this work by modifying our seismic tomography algorithm to incorporate arrival polarizations (azimuths). Synthetic tests will be presented to demonstrate the improvements in velocity structure when arrival polarizations are incorporated. These tests will compare the synthetic model recovered when FZHW/DWSA arrivals as well as existing P-wave arrival time data are inverted to that recovered with the same dataset with the inclusion of arrival polarizations. We plan to extend this work to carry out a full scale seismic tomography/relocation inversion at Parkfield, CA utilizing arrival polarizations from all first-P arrivals, and FZHW/DWSA arrivals as well as existing P-wave arrival time data. This effort requires the determination of polarization data for all P-waves and FZHW's at Parkfield. To this end, we use changes in the arrival azimuth from fault normal to source-receiver direction to identify FZHW and
Hu, Jiangtao; Cao, Junxing; Wang, Huazhong; Wang, Xingjian; Jiang, Xudong
2017-12-01
First-arrival traveltime computation for quasi-P waves in transversely isotropic (TI) media is the key component of tomography and depth migration. It is appealing to use the fast marching method in isotropic media as it efficiently computes traveltime along an expanding wavefront. It uses the finite difference method to solve the eikonal equation. However, applying the fast marching method in anisotropic media faces challenges because the anisotropy introduces additional nonlinearity in the eikonal equation and solving this nonlinear eikonal equation with the finite difference method is challenging. To address this problem, we present a Fermat’s principle-based fast marching method to compute traveltime in two-dimensional TI media. This method is applicable in both vertical and tilted TI (VTI and TTI) media. It computes traveltime along an expanding wavefront using Fermat’s principle instead of the eikonal equation. Thus, it does not suffer from the nonlinearity of the eikonal equation in TI media. To compute traveltime using Fermat’s principle, the explicit expression of group velocity in TI media is required to describe the ray propagation. The moveout approximation is adopted to obtain the explicit expression of group velocity. Numerical examples on both VTI and TTI models show that the traveltime contour obtained by the proposed method matches well with the wavefront from the wave equation. This shows that the proposed method could be used in depth migration and tomography.
Imaging the Mediterranean upper mantle by p- wave travel time tomography
Directory of Open Access Journals (Sweden)
A. Morelli
1997-06-01
Full Text Available Travel times of P-waves in the Euro-Mediterranean region show strong and consistent lateral variations, which can be associated to structural heterogeneity in the underlying crust and mantle. We analyze regional and tele- seismic data from the International Seismological Centre data base to construct a three-dimensional velocity model of the upper mantle. We parameterize the model by a 3D grid of nodes -with approximately 50 km spacing -with a linear interpolation law, which constitutes a three-dimensional continuous representation of P-wave velocity. We construct summary travel time residuals between pairs of cells of the Earth's surface, both inside our study area and -with a broader spacing -on the whole globe. We account for lower mantle heterogeneity outside the modeled region by using empirical corrections to teleseismic travel times. The tomo- graphic images show generai agreement with other seismological studies of this area, with apparently higher detail attained in some locations. The signature of past and present lithospheric subduction, connected to Euro- African convergence, is a prominent feature. Active subduction under the Tyrrhenian and Hellenic arcs is clearly imaged as high-velocity bodies spanning the whole upper mantle. A clear variation of the lithospheric structure beneath the Northem and Southern Apennines is observed, with the boundary running in correspon- dence of the Ortona-Roccamonfina tectonic lineament. The western section of the Alps appears to have better developed roots than the eastern, possibly reflecting à difference in past subduction of the Tethyan lithosphere and subsequent continental collision.
Managing customer arrivals with time windows
DEFF Research Database (Denmark)
Chen, Gang; Jiang, Liping
2016-01-01
Due to increasing container traffic and mega-ships, many seaports face challenges of huge amounts of truck arrivals and congestion problem at terminal gates, which affect port efficiency and generate serious air pollution. To solve this congestion problem, we propose a solution of managing truck...... arrivals with time windows based on the truck-vessel service relationship, specifically trucks delivering containers for the same vessel share one common time window. Time windows can be optimized with different strategies. In this paper, we first propose a framework for installing this solution...
Quantum arrival times and operator normalization
International Nuclear Information System (INIS)
Hegerfeldt, Gerhard C.; Seidel, Dirk; Gonzalo Muga, J.
2003-01-01
A recent approach to arrival times used the fluorescence of an atom entering a laser illuminated region, and the resulting arrival-time distribution was close to the axiomatic distribution of Kijowski, but not exactly equal, neither in limiting cases nor after compensation of reflection losses by normalization on the level of expectation values. In this paper we employ a normalization on the level of operators, recently proposed in a slightly different context. We show that in this case the axiomatic arrival-time distribution of Kijowski is recovered as a limiting case. In addition, it is shown that Allcock's complex potential model is also a limit of the physically motivated fluorescence approach and connected to Kijowski's distribution through operator normalization
Advances on the automatic estimation of the P-wave onset time
Directory of Open Access Journals (Sweden)
Luz García
2016-09-01
Full Text Available This work describes the automatic picking of the P-phase arrivals of the 3*106 seismic registers originated during the TOMO-ETNA experiment. Air-gun shots produced by the vessel “Sarmiento de Gamboa” and contemporary passive seismicity occurring in the island are recorded by a dense network of stations deployed for the experiment. In such scenario, automatic processing is needed given: (i the enormous amount of data, (ii the low Signal-to-Noise ratio of many of the available registers and, (iii the accuracy needed for the velocity tomography resulting from the experiment. A preliminary processing is performed with the records obtained from all stations. Raw data formats from the different types of stations are unified, eliminating defective records and reducing noise through filtering in the band of interest for the phase picking. The Advanced Multiband Picking Algorithm (AMPA is then used to process the big database obtained and determine the travel times of the seismic phases. The approach of AMPA, based on frequency multiband denoising and enhancement of expected arrivals through optimum detectors, is detailed together with its calibration and quality assessment procedure. Examples of its usage for active and passive seismic events are presented.
True Time API Link (real time arrival info)
Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This link will take you to the site where you can create an account to access Port Authority's real time arrival information. To request access to Port Authority's...
Constraining dark matter late-time energy injection: decays and p-wave annihilations
Energy Technology Data Exchange (ETDEWEB)
Diamanti, Roberta; Mena, Olga; Palomares-Ruiz, Sergio; Vincent, Aaron C. [Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, Apartado de Correos 22085, E-46071 Valencia (Spain); Lopez-Honorez, Laura, E-mail: R.Diamanti@uva.nl, E-mail: llopezho@vub.ac.be, E-mail: omena@ific.uv.es, E-mail: sergio.palomares.ruiz@ific.uv.es, E-mail: vincent@ific.uv.es [Theoretische Natuurkunde Vrije Universiteit Brussel and The International Solvay Institutes Pleinlaan 2, B-1050 Brussels (Belgium)
2014-02-01
We use the latest cosmic microwave background (CMB) observations to provide updated constraints on the dark matter lifetime as well as on p-wave suppressed annihilation cross sections in the 1 MeV to 1 TeV mass range. In contrast to scenarios with an s-wave dominated annihilation cross section, which mainly affect the CMB close to the last scattering surface, signatures associated with these scenarios essentially appear at low redshifts (z∼<50) when structure began to form, and thus manifest at lower multipoles in the CMB power spectrum. We use data from Planck, WMAP9, SPT and ACT, as well as Lyman–α measurements of the matter temperature at z ∼ 4 to set a 95% confidence level lower bound on the dark matter lifetime of ∼ 4 × 10{sup 25} s for m{sub χ} = 100 MeV. This bound becomes lower by an order of magnitude at m{sub χ} = 1 TeV due to inefficient energy deposition into the intergalactic medium. We also show that structure formation can enhance the effect of p-wave suppressed annihilation cross sections by many orders of magnitude with respect to the background cosmological rate, although even with this enhancement, CMB constraints are not yet strong enough to reach the thermal relic value of the cross section.
Modelling tourists arrival using time varying parameter
Suciptawati, P.; Sukarsa, K. G.; Kencana, Eka N.
2017-06-01
The importance of tourism and its related sectors to support economic development and poverty reduction in many countries increase researchers’ attentions to study and model tourists’ arrival. This work is aimed to demonstrate time varying parameter (TVP) technique to model the arrival of Korean’s tourists to Bali. The number of Korean tourists whom visiting Bali for period January 2010 to December 2015 were used to model the number of Korean’s tourists to Bali (KOR) as dependent variable. The predictors are the exchange rate of Won to IDR (WON), the inflation rate in Korea (INFKR), and the inflation rate in Indonesia (INFID). Observing tourists visit to Bali tend to fluctuate by their nationality, then the model was built by applying TVP and its parameters were approximated using Kalman Filter algorithm. The results showed all of predictor variables (WON, INFKR, INFID) significantly affect KOR. For in-sample and out-of-sample forecast with ARIMA’s forecasted values for the predictors, TVP model gave mean absolute percentage error (MAPE) as much as 11.24 percent and 12.86 percent, respectively.
The arrival time distribution of muons in extensive air showers
International Nuclear Information System (INIS)
Van der Walt, D.J.
1984-01-01
An experiment was done to investigate the lateral dependence of the muon arrival time distribution in extensive air showers at small core distances. In the present experiment the muon arrival time distribution was investigated by measuring the relative arrival times between single muons in five fast Cerenkov detectors beneath 500g/cm 2 of concrete and at an atmospheric depth of 880g/cm 2 . It is shown that, although it is not possible to determine the arrival time distribution as such, it is possible to interpret the relative arrival times between muons in terms of the differences between the order statistics of a sample drawn from the arrival time distribution. The relationship between the arrival time distribution of muons relative to the first detected muon and the muon arrival time distribution is also derived. It was found that the dispersion of the muon arrival time distribution does not increase significantly with increasing core distance between 10m and 60m from the core. A comparison with theoretical distributions obtained from model calculations for proton initiated showers indicate that 1. the mean delay of muons with respect to the first detected muon is significantly larger than that expected from the model and 2. the observed dispersion is also significantly larger than the predicted dispersion for core distances between 10m and 60m
Estimating bus passenger waiting times from incomplete bus arrivals data
McLeod, F.N.
2007-01-01
This paper considers the problem of estimating bus passenger waiting times at bus stops using incomplete bus arrivals data. This is of importance to bus operators and regulators as passenger waiting time is a key performance measure. Average waiting times are usually estimated from bus headways, that is, time gaps between buses. It is both time-consuming and expensive to measure bus arrival times manually so methods using automatic vehicle location systems are attractive; however, these syste...
Estimated time of arrival and debiasing the time saving bias.
Eriksson, Gabriella; Patten, Christopher J D; Svenson, Ola; Eriksson, Lars
2015-01-01
The time saving bias predicts that the time saved when increasing speed from a high speed is overestimated, and underestimated when increasing speed from a slow speed. In a questionnaire, time saving judgements were investigated when information of estimated time to arrival was provided. In an active driving task, an alternative meter indicating the inverted speed was used to debias judgements. The simulated task was to first drive a distance at a given speed, and then drive the same distance again at the speed the driver judged was required to gain exactly 3 min in travel time compared with the first drive. A control group performed the same task with a speedometer and saved less than the targeted 3 min when increasing speed from a high speed, and more than 3 min when increasing from a low speed. Participants in the alternative meter condition were closer to the target. The two studies corroborate a time saving bias and show that biased intuitive judgements can be debiased by displaying the inverted speed. Practitioner Summary: Previous studies have shown a cognitive bias in judgements of the time saved by increasing speed. This simulator study aims to improve driver judgements by introducing a speedometer indicating the inverted speed in active driving. The results show that the bias can be reduced by presenting the inverted speed and this finding can be used when designing in-car information systems.
Molnar, P.; Chen, W.-P.
1984-01-01
S-P wave travel time residuals were measured in earthquakes in Tibet and the Himalaya in order to study lateral inhomogeneities in the earth's mantle. Average S-P residuals, measured with respect to Jeffrey-Bullen (J-B) tables for 11 earthquakes in the Himalaya are less than +1 second. Average J-B S-P from 10 of 11 earthquakes in Tibet, however, are greater than +1 second even when corrected for local crustal thickness. The largest values, ranging between 2.5 and 4.9 seconds are for five events in central and northern Tibet, and they imply that the average velocities in the crust and upper mantle in this part of Tibet are 4 to 10 percent lower than those beneath the Himalaya. On the basis of the data, it is concluded that it is unlikely that a shield structure lies beneath north central Tibet unless the S-P residuals are due to structural variations occurring deeper than 250 km.
Quantum arrival time formula from decoherent histories
International Nuclear Information System (INIS)
Halliwell, J.J.; Yearsley, J.M.
2009-01-01
We use the decoherent histories approach to quantum mechanics to compute the probability for a wave packet to cross the origin during a given time interval. We define class operators (sums of strings of projectors) characterizing quantum-mechanical crossing and simplify them using a semiclassical approximation. Using these class operators we find that histories crossing the origin during different time intervals are approximately decoherent for a variety of initial states. Probabilities may therefore be assigned and coincide with the flux of the wave packet (the standard semiclassical formula), and are positive. The known initial states for which the flux is negative (backflow states) are shown to correspond to non-decoherent sets of histories, so probabilities may not be assigned.
Quantum arrival-time distributions from intensity functions
DEFF Research Database (Denmark)
Wlodarz, Joachim
2002-01-01
is similar in nature to other time-dependent arrival-type processes occurring, e.g., in population biology or queue theory. A simple but illustrative example related to the well-known Wigner discussion of the time-energy uncertainty relation is given and the numerical results obtained are compared...
P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model
Directory of Open Access Journals (Sweden)
D. Draebing
2012-10-01
Full Text Available P-wave refraction seismics is a key method in permafrost research but its applicability to low-porosity rocks, which constitute alpine rock walls, has been denied in prior studies. These studies explain p-wave velocity changes in freezing rocks exclusively due to changing velocities of pore infill, i.e. water, air and ice. In existing models, no significant velocity increase is expected for low-porosity bedrock. We postulate, that mixing laws apply for high-porosity rocks, but freezing in confined space in low-porosity bedrock also alters physical rock matrix properties. In the laboratory, we measured p-wave velocities of 22 decimetre-large low-porosity (< 10% metamorphic, magmatic and sedimentary rock samples from permafrost sites with a natural texture (> 100 micro-fissures from 25 °C to −15 °C in 0.3 °C increments close to the freezing point. When freezing, p-wave velocity increases by 11–166% perpendicular to cleavage/bedding and equivalent to a matrix velocity increase from 11–200% coincident to an anisotropy decrease in most samples. The expansion of rigid bedrock upon freezing is restricted and ice pressure will increase matrix velocity and decrease anisotropy while changing velocities of the pore infill are insignificant. Here, we present a modified Timur's two-phase-equation implementing changes in matrix velocity dependent on lithology and demonstrate the general applicability of refraction seismics to differentiate frozen and unfrozen low-porosity bedrock.
Bennington, Ninfa L.; Thurber, Clifford; Peng, Zhigang; Zhang, Haijiang; Zhao, Peng
2013-03-01
We present a three-dimensional (3D) P wave velocity (Vp) model of the Parkfield region that utilizes existing P wave arrival time data, including fault zone head waves (FZHWs), and data from direct wave secondary arrivals (DWSAs). The first-arrival and DWSA travel times are obtained as the global- and local-minimum travel time paths, respectively. The inclusion of FZHWs and DWSAs results in as much as a 5% and a 10% increase in the across-fault velocity contrast, respectively, for the Vp model at Parkfield relative to that of Thurber et al. [2006]. Viewed along strike, three pronounced velocity contrast regions are observed: a pair of strong positive velocity contrasts (SW fast), one NW of the 1966 Parkfield earthquake hypocenter and the other SE of the 2004 Parkfield earthquake hypocenter, and a strong negative velocity contrast (NE fast) between the two hypocenters. The negative velocity contrast partially to entirely encompasses peak coseismic slip estimated in several slip models for the 2004 earthquake, suggesting that the negative velocity contrast played a part in defining the rupture patch of the 2004 Parkfield earthquake. Following Ampuero and Ben-Zion (2008), the pattern of velocity contrasts is consistent with the observed bilateral rupture propagation for the 2004 Parkfield earthquake. Although the velocity contrasts also suggest bilateral rupture propagation for the 1966 Parkfield earthquake, the fault is creeping to the NW here, i.e., exhibiting velocity-strengthening behavior. Thus, it is not surprising that rupture propagated only SE during this event.
Original Research Factors associated with hospital arrival time after ...
African Journals Online (AJOL)
Original Research. Factors associated with hospital arrival time after the onset of stroke symptoms: A cross-sectional study at two teaching hospitals in Harare, Zimbabwe .... hypertension causing small vessel disease which outweigh the causes of ..... Stroke Mechanism in Atherosclerotic Middle Cerebral Artery Disease:.
Spectral information for detection of acoustic time to arrival
DEFF Research Database (Denmark)
Gordon, Michael S.; Russo, Frank A.; MacDonald, Ewen
2013-01-01
The exponential increase of intensity for an approaching sound source provides salient information for a listener to make judgments of time to arrival (TTA). Specifically, a listener will experience a greater rate of increasing intensity for higher than for lower frequencies during a sound source...
Estimating epidemic arrival times using linear spreading theory
Chen, Lawrence M.; Holzer, Matt; Shapiro, Anne
2018-01-01
We study the dynamics of a spatially structured model of worldwide epidemics and formulate predictions for arrival times of the disease at any city in the network. The model is composed of a system of ordinary differential equations describing a meta-population susceptible-infected-recovered compartmental model defined on a network where each node represents a city and the edges represent the flight paths connecting cities. Making use of the linear determinacy of the system, we consider spreading speeds and arrival times in the system linearized about the unstable disease free state and compare these to arrival times in the nonlinear system. Two predictions are presented. The first is based upon expansion of the heat kernel for the linearized system. The second assumes that the dominant transmission pathway between any two cities can be approximated by a one dimensional lattice or a homogeneous tree and gives a uniform prediction for arrival times independent of the specific network features. We test these predictions on a real network describing worldwide airline traffic.
Energy Technology Data Exchange (ETDEWEB)
Simmons, N. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Myers, S. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Johannesson, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Matzel, E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2012-10-06
[1] We develop a global-scale P wave velocity model (LLNL-G3Dv3) designed to accurately predict seismic travel times at regional and teleseismic distances simultaneously. The model provides a new image of Earth's interior, but the underlying practical purpose of the model is to provide enhanced seismic event location capabilities. The LLNL-G3Dv3 model is based on ∼2.8 millionP and Pnarrivals that are re-processed using our global multiple-event locator called Bayesloc. We construct LLNL-G3Dv3 within a spherical tessellation based framework, allowing for explicit representation of undulating and discontinuous layers including the crust and transition zone layers. Using a multiscale inversion technique, regional trends as well as fine details are captured where the data allow. LLNL-G3Dv3 exhibits large-scale structures including cratons and superplumes as well numerous complex details in the upper mantle including within the transition zone. Particularly, the model reveals new details of a vast network of subducted slabs trapped within the transition beneath much of Eurasia, including beneath the Tibetan Plateau. We demonstrate the impact of Bayesloc multiple-event location on the resulting tomographic images through comparison with images produced without the benefit of multiple-event constraints (single-event locations). We find that the multiple-event locations allow for better reconciliation of the large set of direct P phases recorded at 0–97° distance and yield a smoother and more continuous image relative to the single-event locations. Travel times predicted from a 3-D model are also found to be strongly influenced by the initial locations of the input data, even when an iterative inversion/relocation technique is employed.
The Measurement and Interpretation of Surface Wave Group Arrival Times
Masters, G.; Kane, D.; Morrow, J.; Zhou, Y.; Tromp, J.
2005-12-01
We have recently developed an efficient technique for measuring the relative group arrival times of surface waves by using cross-correlation and cluster analysis of waveform envelope functions. Applying the analysis to minor arc Love and Rayleigh waves in the frequency band 7 to 35 mHz for all events over magnitude 5.5 results in a dataset of over 200,000 measurements at each frequency for long period Rayleigh waves (frequency less than 25 mHz) and about 100,000 measurements at the shorter periods. Analysis of transverse components results in about half as many Love wave measurements. Simple ray theory inversions of the relative arrival times for apparent group velocity produce maps which are accurate representations of the data (often over 90% variance reduction of the relative arrival times) and which show features strongly correlated with tectonics and crustal thickness. The apparent group velocity variations can be extremely large: 30% velocity variations for 20 mHz Rayleigh waves and 40% variations for 30 mHz Rayleigh waves and can have abrupt lateral changes. This raises the concern that non-ray theory effects could be important. Indeed, a recent analysis by Dahlen and Zhou (personal communication) suggests that the group arrival times should be a functions of both the group velocity AND the phase velocity. The simplest way to test the interpretation of the measurements is to perform the analysis on synthetic seismograms computed for a realistic model of the Earth. Here, we use the SEM with a model which incorporates realistic crust and mantle structure. We are currently computing synthetics for a suite of roughly 1000 events recorded globally that extend to a period of 18 seconds. We shall present the results of applying both ray-based and finite frequency inversions to the synthetic data as well as evaluating the effects of off path propagation at short periods using surface wave ray tracing.
Empirical estimation of the arrival time of ICME Shocks
Shaltout, Mosalam
Empirical estimation of the arrival time of ICME Shocks Mosalam Shaltout1 ,M.Youssef 1and R.Mawad2 1 National Research Institute of Astronomy and Geophysics (NRIAG) ,Helwan -Cairo-Egypt Email: mosalamshaltout@hotmail.com 2 Faculty of Science-Monifiia University-Physics Department-Shiben Al-Koum -Monifiia-Egypt We are got the Data of the SSC events from Preliminary Reports of the ISGI (Institut de Physique du Globe, France) .Also we are selected the same CME interval 1996-2005 from SOHO/LASCO/C2.We have estimated the arrival time of ICME shocks during solar cycle 23rd (1996-2005), we take the Sudden storm commencement SSC as a indicator of the arrival of CMEs at the Earth's Magnetosphere (ICME).Under our model ,we selected 203 ICME shock-SSC associated events, we got an imperial relation between CME velocity and their travel time, from which we obtained high correlation between them, R=0.75.
Li, Xinya; Deng, Zhiqun Daniel; Rauchenstein, Lynn T.; Carlson, Thomas J.
2016-04-01
Locating the position of fixed or mobile sources (i.e., transmitters) based on measurements obtained from sensors (i.e., receivers) is an important research area that is attracting much interest. In this paper, we review several representative localization algorithms that use time of arrivals (TOAs) and time difference of arrivals (TDOAs) to achieve high signal source position estimation accuracy when a transmitter is in the line-of-sight of a receiver. Circular (TOA) and hyperbolic (TDOA) position estimation approaches both use nonlinear equations that relate the known locations of receivers and unknown locations of transmitters. Estimation of the location of transmitters using the standard nonlinear equations may not be very accurate because of receiver location errors, receiver measurement errors, and computational efficiency challenges that result in high computational burdens. Least squares and maximum likelihood based algorithms have become the most popular computational approaches to transmitter location estimation. In this paper, we summarize the computational characteristics and position estimation accuracies of various positioning algorithms. By improving methods for estimating the time-of-arrival of transmissions at receivers and transmitter location estimation algorithms, transmitter location estimation may be applied across a range of applications and technologies such as radar, sonar, the Global Positioning System, wireless sensor networks, underwater animal tracking, mobile communications, and multimedia.
Automatic arrival time detection for earthquakes based on Modified Laplacian of Gaussian filter
Saad, Omar M.; Shalaby, Ahmed; Samy, Lotfy; Sayed, Mohammed S.
2018-04-01
Precise identification of onset time for an earthquake is imperative in the right figuring of earthquake's location and different parameters that are utilized for building seismic catalogues. P-wave arrival detection of weak events or micro-earthquakes cannot be precisely determined due to background noise. In this paper, we propose a novel approach based on Modified Laplacian of Gaussian (MLoG) filter to detect the onset time even in the presence of very weak signal-to-noise ratios (SNRs). The proposed algorithm utilizes a denoising-filter algorithm to smooth the background noise. In the proposed algorithm, we employ the MLoG mask to filter the seismic data. Afterward, we apply a Dual-threshold comparator to detect the onset time of the event. The results show that the proposed algorithm can detect the onset time for micro-earthquakes accurately, with SNR of -12 dB. The proposed algorithm achieves an onset time picking accuracy of 93% with a standard deviation error of 0.10 s for 407 field seismic waveforms. Also, we compare the results with short and long time average algorithm (STA/LTA) and the Akaike Information Criterion (AIC), and the proposed algorithm outperforms them.
Stochastic Resonance and First Arrival Time for Excitable Systems
Duki, Solomon Fekade; Taye, Mesfin Asfaw
2018-06-01
We study the noise induced thermally activated barrier crossing of Brownian particles that hop in a piecewise linear potential. Using the exact analytic solutions and via numerical simulations not only we explore the dependence for the first passage time of a single particle but also we calculate the first arrival time for one particle out of N particles. The first arrival time decreases as the number of particles increases as expected. We then explore the thermally activated barrier crossing rate of the system in the presence of time varying signal. The dependence of signal to noise ratio SNR as well as the power amplification (η ) on model parameters is explored. η and SNR depict a pronounced peak at particular noise strength. In the presence of N particles, η is considerably amplified as N steps up showing the weak periodic signal plays a vital role in controlling the noise induced dynamics of the system. Moreover, for the sake of generality, the viscous friction γ is considered to decrease exponentially when the temperature T of the medium increases (γ =Be^{-A T}) as proposed originally by Reynolds (Philos Trans R Soc Lond 177:157, 1886).
Time of arrival based location estimation for cooperative relay networks
Çelebi, Hasari Burak
2010-09-01
In this paper, we investigate the performance of a cooperative relay network performing location estimation through time of arrival (TOA). We derive Cramer-Rao lower bound (CRLB) for the location estimates using the relay network. The analysis is extended to obtain average CRLB considering the signal fluctuations in both relay and direct links. The effects of the channel fading of both relay and direct links and amplification factor and location of the relay node on average CRLB are investigated. Simulation results show that the channel fading of both relay and direct links and amplification factor and location of relay node affect the accuracy of TOA based location estimation. ©2010 IEEE.
Time of arrival based location estimation for cooperative relay networks
Ç elebi, Hasari Burak; Abdallah, Mohamed M.; Hussain, Syed Imtiaz; Qaraqe, Khalid A.; Alouini, Mohamed-Slim
2010-01-01
In this paper, we investigate the performance of a cooperative relay network performing location estimation through time of arrival (TOA). We derive Cramer-Rao lower bound (CRLB) for the location estimates using the relay network. The analysis is extended to obtain average CRLB considering the signal fluctuations in both relay and direct links. The effects of the channel fading of both relay and direct links and amplification factor and location of the relay node on average CRLB are investigated. Simulation results show that the channel fading of both relay and direct links and amplification factor and location of relay node affect the accuracy of TOA based location estimation. ©2010 IEEE.
Arrival-Time Detection and Ultrasonic Flow-Meter Applications
International Nuclear Information System (INIS)
Willatzen, Morten; Soendergaard, Peter; Latino, Carl; Voss, Frands; Andersen, Niels Lervad; Brokate, Martin; Bounaim, Aicha
2006-01-01
The Danfoss problem on ultrasonic flow measurement has been separated into three parts each handled by a subgroup of the authors listed above. The first subgroup deals with a presentation of modelling equations describing the physics of ultrasonic flow meters employing reciprocal ultrasonic transducer systems. The mathematical model presented allows the electrical output signal to be determined corresponding to any time-dependent electrical input signal. The transducers modelled consist of a piezoceramic material layer and a passive acoustic matching layer. The second subgroup analyzes the possibility of coding the input signal so as to simplify arrival-time detection by re.nding the coded input sequence in the received signal. The narrow-band nature of the transducers makes this problem non-trivial but suggestions for improvement are proposed. The analysis given is based on traditional autoand cross-correlation techniques. The third subgroup attempts to improve existing correlation methods in determining arrival-time detection of signals. A mathematical formulation of the problem is given and the application to a set of real signals provided by Danfoss A/S is performed with good results
Energy Technology Data Exchange (ETDEWEB)
Li, Xinya [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Deng, Zhiqun Daniel [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Rauchenstein, Lynn T. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Carlson, Thomas J. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
2016-04-01
Locating the position of fixed or mobile sources (i.e., transmitters) based on received measurements from sensors is an important research area that is attracting much research interest. In this paper, we present localization algorithms using time of arrivals (TOA) and time difference of arrivals (TDOA) to achieve high accuracy under line-of-sight conditions. The circular (TOA) and hyperbolic (TDOA) location systems both use nonlinear equations that relate the locations of the sensors and tracked objects. These nonlinear equations can develop accuracy challenges because of the existence of measurement errors and efficiency challenges that lead to high computational burdens. Least squares-based and maximum likelihood-based algorithms have become the most popular categories of location estimators. We also summarize the advantages and disadvantages of various positioning algorithms. By improving measurement techniques and localization algorithms, localization applications can be extended into the signal-processing-related domains of radar, sonar, the Global Positioning System, wireless sensor networks, underwater animal tracking, mobile communications, and multimedia.
Traffic Incident Clearance Time and Arrival Time Prediction Based on Hazard Models
Directory of Open Access Journals (Sweden)
Yang beibei Ji
2014-01-01
Full Text Available Accurate prediction of incident duration is not only important information of Traffic Incident Management System, but also an effective input for travel time prediction. In this paper, the hazard based prediction models are developed for both incident clearance time and arrival time. The data are obtained from the Queensland Department of Transport and Main Roads’ STREAMS Incident Management System (SIMS for one year ending in November 2010. The best fitting distributions are drawn for both clearance and arrival time for 3 types of incident: crash, stationary vehicle, and hazard. The results show that Gamma, Log-logistic, and Weibull are the best fit for crash, stationary vehicle, and hazard incident, respectively. The obvious impact factors are given for crash clearance time and arrival time. The quantitative influences for crash and hazard incident are presented for both clearance and arrival. The model accuracy is analyzed at the end.
Seasonality of P wave microseisms from NCF-based beamforming using ChinArray
Wang, Weitao; Gerstoft, Peter; Wang, Baoshan
2018-06-01
Teleseismic P wave microseisms produce interference signals with high apparent velocity in noise cross-correlation functions (NCFs). Sources of P wave microseisms can be located with NCFs from seismic arrays. Using the vertical-vertical component NCFs from a large-aperture array in southwestern China (ChinArray), we studied the P wave source locations and their seasonality of microseisms at two period bands (8-12 and 4-8 s) with an NCF-based beamforming method. The sources of P, PP and PKPbc waves are located. The ambiguity between P and PP source locations is analysed using averaged significant ocean wave height and sea surface pressure as constraints. The results indicate that the persistent P wave sources are mainly located in the deep oceans such as the North Atlantic, North Pacific and Southern Ocean, in agreement with previous studies. The Gulf of Alaska is found to generate P waves favouring the 8-12 s period band. The seasonality of P wave sources is consistent with the hemispheric storm pattern, which is stronger in local winter. Using the identified sources, arrival times of the interference signals are predicted and agree well with observations. The interference signals exhibit seasonal variation, indicating that body wave microseisms in southwestern China are from multiple seasonal sources.
Equilibrium arrival times to queues with general service times and non-linear utility functions
DEFF Research Database (Denmark)
Breinbjerg, Jesper
2017-01-01
by a general utility function which is decreasing in the waiting time and service completion time of each customer. Applications of such queueing games range from people choosing when to arrive at a grand opening sale to travellers choosing when to line up at the gate when boarding an airplane. We develop...
Chi Durán, R. K.; Comte, D.; Diaz, M. A.; Silva, J. F.
2017-12-01
In this work, new strategies for automatic identification of P- and S-wave arrival times from digital recorded local seismograms are proposed and analyzed. The database of arrival times previously identified by a human reader was compared with automatic identification techniques based on the Fourier transformation in reduced time (spectrograms), fractal analysis, and the basic matching pursuit algorithm. The first two techniques were used to identify the P-wave arrival times, while the third was used for the identification of the S-wave. For validation, the results were compared with the short-time average over long-time average (STA/LTA) of Rietbrock et al., Geophys Res Lett 39(8), (2012) for the database of aftershocks of the 2010 Maule Mw = 8.8 earthquake. The identifiers proposed in this work exhibit good results that outperform the STA/LTA identifier in many scenarios. The average difference from the reference picks (times obtained by the human reader) in P- and S-wave arrival times is 1 s.
CAT-PUMA: CME Arrival Time Prediction Using Machine learning Algorithms
Liu, Jiajia; Ye, Yudong; Shen, Chenglong; Wang, Yuming; Erdélyi, Robert
2018-04-01
CAT-PUMA (CME Arrival Time Prediction Using Machine learning Algorithms) quickly and accurately predicts the arrival of Coronal Mass Ejections (CMEs) of CME arrival time. The software was trained via detailed analysis of CME features and solar wind parameters using 182 previously observed geo-effective partial-/full-halo CMEs and uses algorithms of the Support Vector Machine (SVM) to make its predictions, which can be made within minutes of providing the necessary input parameters of a CME.
An Exact Solution of the Gamma Ray Burst Arrival Time Analysis ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
An Exact Solution of the Gamma Ray Burst Arrival Time Analysis. Problem. S. Sinha ISRO Satellite Center, Bangalore 560 017, India. Abstract. An analytical solution of the GRB arrival time analysis is presented. The errors in the position of the GRB resulting from timing and position errors of different satellites are calculated.
van der Spoel, Sjoerd; Amrit, Chintan Amrit; van Hillegersberg, Jos
2017-01-01
Distribution centres (DCs) are the hubs connecting transport streams in the supply chain. The synchronisation of coming and going cargo at a DC requires reliable arrival times. To achieve this, a reliable method to predict arrival times is needed. A literature review was performed to find the
Precise and accurate train run data: Approximation of actual arrival and departure times
DEFF Research Database (Denmark)
Richter, Troels; Landex, Alex; Andersen, Jonas Lohmann Elkjær
with the approximated actual arrival and departure times. As a result, all future statistics can now either be based on track circuit data with high precision or approximated actual arrival times with a high accuracy. Consequently, performance analysis will be more accurate, punctuality statistics more correct, KPI...
Obtaining location/arrival-time and location/outflow-quantity distributions for steady flow systems
International Nuclear Information System (INIS)
Anon.
1977-01-01
A steady, two-dimensional flow system is used to demonstrate the application of location/arrival-time and location/outflow-quantity curves in determining the environmental consequences of groundwater contamination. The subsurface geologic and hydrologic evaluations needed to obtain the arrival results involve a sequence of four phases: system identification, new potential determination, flow systems kinematics, and contaminant transport analysis. Once these phases are completed, they are effectively summarized and easily used to evaluate environmental consequences through the arrival distributions
Automatic pickup of arrival time of channel wave based on multi-channel constraints
Wang, Bao-Li
2018-03-01
Accurately detecting the arrival time of a channel wave in a coal seam is very important for in-seam seismic data processing. The arrival time greatly affects the accuracy of the channel wave inversion and the computed tomography (CT) result. However, because the signal-to-noise ratio of in-seam seismic data is reduced by the long wavelength and strong frequency dispersion, accurately timing the arrival of channel waves is extremely difficult. For this purpose, we propose a method that automatically picks up the arrival time of channel waves based on multi-channel constraints. We first estimate the Jaccard similarity coefficient of two ray paths, then apply it as a weight coefficient for stacking the multichannel dispersion spectra. The reasonableness and effectiveness of the proposed method is verified in an actual data application. Most importantly, the method increases the degree of automation and the pickup precision of the channel-wave arrival time.
On-line scheduling of two-machine open shops where jobs arrive over time
Chen, B.; Vestjens, A.P.A.; Woeginger, G.J.
1998-01-01
We investigate the problem of on-line scheduling two-machine open shops with the objective of minimizing the makespan.Jobs arrive independently over time, and the existence of a job is not known until its arrival. In the clairvoyant on-line model, the processing requirement of every job becomes
Dalmau Codina, Ramon; Prats Menéndez, Xavier
2017-01-01
Continuous descent operations with controlled times of arrival at one or several metering fixes could enable environmentally friendly procedures without compromising terminal airspace capacity. This paper focuses on controlled time of arrival updates once the descent has been already initiated, assessing the feasible time window (and associated fuel consumption) of continuous descent operations requiring neither thrust nor speed-brake usage along the whole descent (i.e. only elevator control ...
International Nuclear Information System (INIS)
Donos, Aristomenis; Gauntlett, Jerome P; Pantelidou, Christiana
2014-01-01
We construct electrically charged, asymptotically AdS 5 black hole solutions that are dual to d = 4 CFTs in a superfluid phase with either p-wave or (p + ip)-wave order. The two types of black holes have non-vanishing charged two-form in the bulk and appear at the same critical temperature in the unbroken phase. Both the p-wave and the (p + ip)-wave phase can be thermodynamically preferred, depending on the mass and charge of the two-form, and there can also be first order transitions between them. The p-wave black holes have a helical structure and some of them exhibit the phenomenon of pitch inversion as the temperature is decreased. Both the p-wave and the (p + ip)-wave black holes have zero entropy density ground states at zero temperature and we identify some new ground states which exhibit scaling symmetry, including a novel scenario for the emergence of conformal symmetry in the IR. (paper)
Sojourn time distributions in a Markovian G-queue with batch arrival and batch removal
Directory of Open Access Journals (Sweden)
Yang Woo Shin
1999-01-01
Full Text Available We consider a single server Markovian queue with two types of customers; positive and negative, where positive customers arrive in batches and arrivals of negative customers remove positive customers in batches. Only positive customers form a queue and negative customers just reduce the system congestion by removing positive ones upon their arrivals. We derive the LSTs of sojourn time distributions for a single server Markovian queue with positive customers and negative customers by using the first passage time arguments for Markov chains.
A review of the decoherent histories approach to the arrival time problem in quantum theory
International Nuclear Information System (INIS)
Yearsley, James M
2011-01-01
We review recent progress in understanding the arrival time problem in quantum mechanics, from the point of view of the decoherent histories approach to quantum theory. We begin by discussing the arrival time problem, focussing in particular on the role of the probability current in the expected classical solution. After a brief introduction to decoherent histories we review the use of complex potentials in the construction of appropriate class operators. We then discuss the arrival time problem for a particle coupled to an environment, and review how the arrival time probability can be expressed in terms of a POVM in this case. We turn finally to the question of decoherence of the corresponding histories, and we show that this can be achieved for simple states in the case of a free particle, and for general states for a particle coupled to an environment.
A fire management simulation model using stochastic arrival times
Eric L. Smith
1987-01-01
Fire management simulation models are used to predict the impact of changes in the fire management program on fire outcomes. As with all models, the goal is to abstract reality without seriously distorting relationships between variables of interest. One important variable of fire organization performance is the length of time it takes to get suppression units to the...
Analysing passenger arrivals rates and waiting time at bus stops
Kaparias, I.; Rossetti, C.; Trozzi, V.
2015-01-01
The present study investigates the rather under-explored topic of passenger waiting times at public transport facilities. Using data collected from part of London’s bus network by means of physical counts, measurements and observations, and complemented by on-site passenger interviews, the waiting behaviour is analysed for a number of bus stops served by different numbers of lines. The analysis employs a wide range of statistical methods and tools, and concentrates on three aspects: passenger...
Detection of time of arrival of ultrasonic pulses
International Nuclear Information System (INIS)
Latino, Carl D; Andersen, Niels Lervad; Voss, Frands
2006-01-01
Applications exist that employ transit-time measurements to determine distances to scattering objects. These include blood-flow measurements, fluid-level detection, nondestructive testing of materials, image processing of geometrical bodies etc. Many of these require extreme accuracy in measuring transit time through a medium. The system typically consists of a transmitter, a medium and a receiver. The signal sent must operate within the limitations imposed by this overall system. Under ideal conditions a finite duration pulse consisting of a sinusoidal signal is sent and received. If the transmitted signal contains an integer number of complete cycles of a single frequency, performing a correlation between transmitted and received signals can accurately recover the transit time information. The method has difficulties especially in the presence of noise. The problem is compounded if the desired accuracy is a small fraction of a single sinusoid period. Noise could cause the correlation results to be off by a complete cycle. For a one MHz signal, one cycle error corresponds to a one microsecond error. For applications requiring nanosecond accuracy, this is not acceptable. Varying the frequency content of the signal reduces the error but requires that the transmitter, receiver and medium all have a broader band spectrum. The improvements we propose here work within a narrow band while enhancing the chance of recovering the signal accurately
time of arrival 3-d position estimation using minimum ads-b receiver ...
African Journals Online (AJOL)
HOD
The location from which a signal is transmitted can be estimated using the time it takes to be detected at a receiver. The difference between transmission time and the detection time is known as time of arrival (TOA). In this work, an algorithm for 3-dimensional (3-D) position estimation (PE) of an emitter using the minimum ...
Does winter region affect spring arrival time and body mass of king eiders in northern Alaska?
Powell, Abby N.; Oppel, Steffen
2009-01-01
Events during the non-breeding season may affect the body condition of migratory birds and influence performance during the following breeding season. Migratory birds nesting in the Arctic often rely on endogenous nutrients for reproductive efforts, and are thus potentially subject to such carry-over effects. We tested whether king eider (Somateria spectabilis) arrival time and body mass upon arrival at breeding grounds in northern Alaska were affected by their choice of a winter region in the Bering Sea. We captured birds shortly after arrival on breeding grounds in early June 2002–2006 at two sites in northern Alaska and determined the region in which individuals wintered using satellite telemetry or stable isotope ratios of head feathers. We used generalized linear models to assess whether winter region explained variation in arrival body mass among individuals by accounting for sex, site, annual variation, and the date a bird was captured. We found no support for our hypothesis that either arrival time or arrival body mass of king eiders differed among winter regions. We conclude that wintering in different regions in the Bering Sea is unlikely to have reproductive consequences for king eiders in our study areas.
Managing truck arrivals with time windows to alleviate gate congestion at container terminals
DEFF Research Database (Denmark)
Chen, G.; Govindan, Kannan; Yang, Z.
2013-01-01
Long truck queues at gates often limit the efficiency of a container terminal and generate serious air pollution. To reduce the gate congestion, this paper proposes a method called'vessel dependent time windows (VDTWs)' to control truck arrivals, which involves partitioning truck entries into gro......Long truck queues at gates often limit the efficiency of a container terminal and generate serious air pollution. To reduce the gate congestion, this paper proposes a method called'vessel dependent time windows (VDTWs)' to control truck arrivals, which involves partitioning truck entries...... into groups and assigning different time windows to the groups. The proposed VDTWs method includes three steps: (1) predicting truck arrivals based on the time window assignment, (2) estimating the queue length of trucks, and (3) optimizing the arrangement of time windows to minimize the total cost...
Distribution of arrival times of muons with energy greater than 10 GeV
International Nuclear Information System (INIS)
Badino, G.; Bianco, P.; Dardo, M.; Fulgione, W.; Galeotti, P.; Periale, L.; Saavedra, O.
1982-01-01
Recent data on the arrival time distribution of EAS of primary energy >=10 14 eV, and of high energy muons detected at great depth (5000 mwe), seem to indicate an excess of short time intervals. We are using an apparatus, installed at 40 mwe underground, and a surface shower array to investigate the distributions of a) the time intervals between muon groups and b) the arrival times of muons with respect to the front of air showers. Preliminary results of this search are presented
Operator-normalized quantum arrival times in the presence of interactions
International Nuclear Information System (INIS)
Hegerfeldt, G.C.; Seidel, D.; Muga, J.G.; Navarro, B.
2004-01-01
We model ideal arrival-time measurements for free quantum particles and for particles subject to an external interaction by means of a narrow and weak absorbing potential. This approach is related to the operational approach of measuring the first photon emitted from a two-level atom illuminated by a laser. By operator normalizing the resulting time-of-arrival distribution, a distribution is obtained which for freely moving particles not only recovers the axiomatically derived distribution of Kijowski for states with purely positive momenta but is also applicable to general momentum components. For particles interacting with a square barrier the mean arrival time and corresponding 'tunneling time' obtained at the transmission side of the barrier become independent of the barrier width (Hartman effect) for arbitrarily wide barriers, i.e., without the transition to the ultraopaque, classical-like regime dominated by wave packet components above the barrier
A study on the impact of prioritising emergency department arrivals on the patient waiting time.
Van Bockstal, Ellen; Maenhout, Broos
2018-05-03
In the past decade, the crowding of the emergency department has gained considerable attention of researchers as the number of medical service providers is typically insufficient to fulfil the demand for emergency care. In this paper, we solve the stochastic emergency department workforce planning problem and consider the planning of nurses and physicians simultaneously for a real-life case study in Belgium. We study the patient arrival pattern of the emergency department in depth and consider different patient acuity classes by disaggregating the arrival pattern. We determine the personnel staffing requirements and the design of the shifts based on the patient arrival rates per acuity class such that the resource staffing cost and the weighted patient waiting time are minimised. In order to solve this multi-objective optimisation problem, we construct a Pareto set of optimal solutions via the -constraints method. For a particular staffing composition, the proposed model minimises the patient waiting time subject to upper bounds on the staffing size using the Sample Average Approximation Method. In our computational experiments, we discern the impact of prioritising the emergency department arrivals. Triaging results in lower patient waiting times for higher priority acuity classes and to a higher waiting time for the lowest priority class, which does not require immediate care. Moreover, we perform a sensitivity analysis to verify the impact of the arrival and service pattern characteristics, the prioritisation weights between different acuity classes and the incorporated shift flexibility in the model.
Arrival time and incidence angle distributions of extensive air showers (EAS) muons
International Nuclear Information System (INIS)
Brancus, I.M.; Duma, M.; Vulpescu, B.; Foeller, M.; Rebel, H.; Voelker, G.; Chilingarian, A.A.
1995-01-01
The arrival time distributions of the muons can be related to the longitudinal EAS development and may provide additional information about the nature of the primary. Based on EAS simulations using the Monte-Carlo code CORSIKA, the correlations between arrival time and incidence angle distributions have been investigated in a case of a set of ideal detectors (10 m x 10 m) placed at various distances from the shower core. Applying advanced statistical techniques based on Bayes decision rule and non-parametric multivariate analysing methods it turns out that the correlations of muon arrival time and incidence angle at various separating distances of about 50 m exhibit promising features for mass discrimination (author)
Sequencing games with Just-in-Time arrival, and related games
Lohmann, E.R.M.A.; Borm, P.E.M.; Slikker, M.
2014-01-01
In this paper sequencing situations with Just-in-Time (JiT) arrival are introduced. This new type of one-machine sequencing situations assumes that a job is available to be handled by the machine as soon as its predecessor is finished. A basic predecessor dependent set-up time is incorporated in the
First arrival time picking for microseismic data based on DWSW algorithm
Li, Yue; Wang, Yue; Lin, Hongbo; Zhong, Tie
2018-03-01
The first arrival time picking is a crucial step in microseismic data processing. When the signal-to-noise ratio (SNR) is low, however, it is difficult to get the first arrival time accurately with traditional methods. In this paper, we propose the double-sliding-window SW (DWSW) method based on the Shapiro-Wilk (SW) test. The DWSW method is used to detect the first arrival time by making full use of the differences between background noise and effective signals in the statistical properties. Specifically speaking, we obtain the moment corresponding to the maximum as the first arrival time of microseismic data when the statistic of our method reaches its maximum. Hence, in our method, there is no need to select the threshold, which makes the algorithm more facile when the SNR of microseismic data is low. To verify the reliability of the proposed method, a series of experiments is performed on both synthetic and field microseismic data. Our method is compared with the traditional short-time and long-time average (STA/LTA) method, the Akaike information criterion, and the kurtosis method. Analysis results indicate that the accuracy rate of the proposed method is superior to that of the other three methods when the SNR is as low as - 10 dB.
Energy Technology Data Exchange (ETDEWEB)
Takahashi, Ryuichi [Faculty of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561 (Japan)
2017-01-20
In this study we demonstrate that general relativity predicts arrival time differences between gravitational wave (GW) and electromagnetic (EM) signals caused by the wave effects in gravitational lensing. The GW signals can arrive earlier than the EM signals in some cases if the GW/EM signals have passed through a lens, even if both signals were emitted simultaneously by a source. GW wavelengths are much larger than EM wavelengths; therefore, the propagation of the GWs does not follow the laws of geometrical optics, including the Shapiro time delay, if the lens mass is less than approximately 10{sup 5} M {sub ⊙}( f /Hz){sup −1}, where f is the GW frequency. The arrival time difference can reach ∼0.1 s ( f /Hz){sup −1} if the signals have passed by a lens of mass ∼8000 M {sub ⊙}( f /Hz){sup −1} with the impact parameter smaller than the Einstein radius; therefore, it is more prominent for lower GW frequencies. For example, when a distant supermassive black hole binary (SMBHB) in a galactic center is lensed by an intervening galaxy, the time lag becomes of the order of 10 days. Future pulsar timing arrays including the Square Kilometre Array and X-ray detectors may detect several time lags by measuring the orbital phase differences between the GW/EM signals in the SMBHBs. Gravitational lensing imprints a characteristic modulation on a chirp waveform; therefore, we can deduce whether a measured arrival time lag arises from intrinsic source properties or gravitational lensing. Determination of arrival time differences would be extremely useful in multimessenger observations and tests of general relativity.
Directory of Open Access Journals (Sweden)
Ana Catarina Delgado de Souza
2002-10-01
Full Text Available Schistosoma mansoni is responsible for lesions that can alter the hemodinamic of the portal venous circulation, lung arterial and venous sistemic systems. Therefore, hemodinamic changes in the ocular circulation of mansonic schistosomotic patients with portal hypertension and hepatofugal venous blood flow is also probable. The purpose of this study was to determine the fluorescein contrast arrival time at the retina of young patients with the hepatosplenic form of schistosomiasis, clinically and surgically treated. The control group included 36 non schistosomotic patients, mean age of 17.3 years, and the case group was represented by 25 schistosomotic patients, mean age of 18.2 years, who were cared for at The University Hospital (Federal University of Pernambuco, Brazil, from 1990 to 2001. They underwent digital angiofluoresceinography and were evaluated for the contrast arrival time at the early retinal venous phase of the exam. Both groups were ophthalmologically examined at the same hospital (Altino Ventura Foundation, Recife, Brazil, using the same technique. There was retardation of the retinal contrast arrival time equal or more than 70 sec in the eyes of three schistosomotic patients (12% and in none of the control group, however, the mean contrast arrival time between the two groups were not statistically different. These findings lend support to the hypothesis that there could be a delay of the eye venous blood flow drainage.
Maximum Likelihood Time-of-Arrival Estimation of Optical Pulses via Photon-Counting Photodetectors
Erkmen, Baris I.; Moision, Bruce E.
2010-01-01
Many optical imaging, ranging, and communications systems rely on the estimation of the arrival time of an optical pulse. Recently, such systems have been increasingly employing photon-counting photodetector technology, which changes the statistics of the observed photocurrent. This requires time-of-arrival estimators to be developed and their performances characterized. The statistics of the output of an ideal photodetector, which are well modeled as a Poisson point process, were considered. An analytical model was developed for the mean-square error of the maximum likelihood (ML) estimator, demonstrating two phenomena that cause deviations from the minimum achievable error at low signal power. An approximation was derived to the threshold at which the ML estimator essentially fails to provide better than a random guess of the pulse arrival time. Comparing the analytic model performance predictions to those obtained via simulations, it was verified that the model accurately predicts the ML performance over all regimes considered. There is little prior art that attempts to understand the fundamental limitations to time-of-arrival estimation from Poisson statistics. This work establishes both a simple mathematical description of the error behavior, and the associated physical processes that yield this behavior. Previous work on mean-square error characterization for ML estimators has predominantly focused on additive Gaussian noise. This work demonstrates that the discrete nature of the Poisson noise process leads to a distinctly different error behavior.
Directory of Open Access Journals (Sweden)
Moon Ho Lee
2008-01-01
Full Text Available A multiserver queueing model that does not have a buffer but has batch arrival of customers is considered. In contrast to the standard batch arrival, in which the entire batch arrives at the system during a single epoch, we assume that the customers of a batch (flow arrive individually in exponentially distributed times. The service time is exponentially distributed. Flows arrive according to a stationary Poisson arrival process. The flow size distribution is geometric. The number of flows that can be simultaneously admitted to the system is under control. The loss of any customer from an admitted flow, with a fixed probability, implies termination of the flow arrival. Analysis of the sojourn time and loss probability of an arbitrary flow is performed.
Preliminary result of P-wave speed tomography beneath North Sumatera region
Energy Technology Data Exchange (ETDEWEB)
Jatnika, Jajat [Earth Science Study Program, Institute of Technology Bandung (Indonesia); Indonesian Meteorological, Climatological and Geophysical Agency (MCGA), Jakarta (Indonesia); Nugraha, Andri Dian, E-mail: nugraha@gf.itb.ac.id [Global Geophysical Research Group, Faculty of Mining and Petroleum Engineering, Insitute of Technology Bandung (Indonesia); Wandono [Indonesian Meteorological, Climatological and Geophysical Agency (MCGA), Jakarta (Indonesia)
2015-04-24
The structure of P-wave speed beneath the North Sumatra region was determined using P-wave arrival times compiled by MCGA from time periods of January 2009 to December 2012 combining with PASSCAL data for February to May 1995. In total, there are 2,246 local earthquake events with 10,666 P-wave phases from 63 stations seismic around the study area. Ray tracing to estimate travel time from source to receiver in this study by applying pseudo-bending method while the damped LSQR method was used for the tomographic inversion. Based on assessment of ray coverage, earthquakes and stations distribution, horizontal grid nodes was set up of 30×30 km2 for inside the study area and 80×80 km2 for outside the study area. The tomographic inversion results show low Vp anomaly beneath Toba caldera complex region and around the Sumatra Fault Zones (SFZ). These features are consistent with previous study. The low Vp anomaly beneath Toba caldera complex are observed around Mt. Pusuk Bukit at depths of 5 km down to 100 km. The interpretation is these anomalies may be associated with ascending hot materials from subduction processes at depths of 80 km down to 100 km. The obtained Vp structure from local tomography will give valuable information to enhance understanding of tectonic and volcanic in this study area.
International Nuclear Information System (INIS)
Xu Chaoyang; Liu Junmin; Fan Yanfang; Ji Guohua
2008-01-01
Joint time-frequency analysis is conducted to construct one joint density function of time and frequency. It can open out one signal's frequency components and their evolvements. It is the new evolvement of Fourier analysis. In this paper, according to the characteristic of seismic signal's noise, one estimation method of seismic signal's first arrival based on triple correlation of joint time-frequency spectrum is introduced, and the results of experiment and conclusion are presented. (authors)
International Nuclear Information System (INIS)
Shah, S.A.; Shah, W.; Shaikh, F.K.
2012-01-01
Flow time analysis is a powerful concept to analyze the flow time of any arriving customer in any system at any instant. A load management mechanism can be employed very effectively in any queueing system by utilizing a system which provides probability of dual service rate. In this paper, we develop and demonstrate the flow and service processes transition diagram to determine the flow time of a customer in a load management late arrival state dependent finite discrete time queueing system with dual service rate where customers are hypo geometrically distributed. We compute the probability mass function of each starting state and total probability mass function. The obtained analytical results are validated with simulation results for varying values of arrival and service probabilities. (author)
An Arrival and Departure Time Predictor for Scheduling Communication in Opportunistic IoT
Pozza, Riccardo; Georgoulas, Stylianos; Moessner, Klaus; Nati, Michele; Gluhak, Alexander; Krco, Srdjan
2016-01-01
In this article, an Arrival and Departure Time Predictor (ADTP) for scheduling communication in opportunistic Internet of Things (IoT) is presented. The proposed algorithm learns about temporal patterns of encounters between IoT devices and predicts future arrival and departure times, therefore future contact durations. By relying on such predictions, a neighbour discovery scheduler is proposed, capable of jointly optimizing discovery latency and power consumption in order to maximize communication time when contacts are expected with high probability and, at the same time, saving power when contacts are expected with low probability. A comprehensive performance evaluation with different sets of synthetic and real world traces shows that ADTP performs favourably with respect to previous state of the art. This prediction framework opens opportunities for transmission planners and schedulers optimizing not only neighbour discovery, but the entire communication process. PMID:27827909
An Arrival and Departure Time Predictor for Scheduling Communication in Opportunistic IoT.
Pozza, Riccardo; Georgoulas, Stylianos; Moessner, Klaus; Nati, Michele; Gluhak, Alexander; Krco, Srdjan
2016-11-04
In this article, an Arrival and Departure Time Predictor (ADTP) for scheduling communication in opportunistic Internet of Things (IoT) is presented. The proposed algorithm learns about temporal patterns of encounters between IoT devices and predicts future arrival and departure times, therefore future contact durations. By relying on such predictions, a neighbour discovery scheduler is proposed, capable of jointly optimizing discovery latency and power consumption in order to maximize communication time when contacts are expected with high probability and, at the same time, saving power when contacts are expected with low probability. A comprehensive performance evaluation with different sets of synthetic and real world traces shows that ADTP performs favourably with respect to previous state of the art. This prediction framework opens opportunities for transmission planners and schedulers optimizing not only neighbour discovery, but the entire communication process.
Monitoring molecular interactions using photon arrival-time interval distribution analysis
Laurence, Ted A [Livermore, CA; Weiss, Shimon [Los Angels, CA
2009-10-06
A method for analyzing/monitoring the properties of species that are labeled with fluorophores. A detector is used to detect photons emitted from species that are labeled with one or more fluorophores and located in a confocal detection volume. The arrival time of each of the photons is determined. The interval of time between various photon pairs is then determined to provide photon pair intervals. The number of photons that have arrival times within the photon pair intervals is also determined. The photon pair intervals are then used in combination with the corresponding counts of intervening photons to analyze properties and interactions of the molecules including brightness, concentration, coincidence and transit time. The method can be used for analyzing single photon streams and multiple photon streams.
Fang, Jing; Yan, Weihong; Jiang, Guo-Xin; Li, Wei; Cheng, Qi
2011-02-01
To observe the time interval between stroke onset and hospital arrival (time-to-hospital) in acute ischemic stroke patients and analyze its putatively associated factors. During the period from November 1, 2006 to August 31, 2008, patients with acute ischemic stroke admitted consecutively to the Department of Neurology, Ninth Hospital, Shanghai, were enrolled in the study. Information of the patients was registered including the time-to-hospital, demographic data, history of stroke, season at attack, neurological symptom at onset, etc. Characteristics of the patients were analyzed and logistic regression analyses were conducted to identify factors associated with the time-to-hospital. There were 536 patients in the study, 290 (54.1%) males and 246 (45.9%) females. The median time-to-hospital was 8h (ranged from 0.1 to 300 h) for all patients. Within 3h after the onset of stroke, 162 patients (30.2%) arrived at our hospital; and within 6h, 278 patients (51.9%). Patients with a history of stroke, unconsciousness at onset, or a high NIHSS score at admission had significantly less time-to-hospital. The time interval between stroke onset and hospital arrival was importance of seeking immediate medical help after stroke onset of patients and their relatives could significantly influence their actions. Copyright © 2010 Elsevier B.V. All rights reserved.
A FIFO based neutron arrival time collection technique for assay of plutonium
International Nuclear Information System (INIS)
Parthasarathy, R.; Saisubalakshmi, D.; Venkatasubramani, C.R.
2004-01-01
The system assays plutonium by counting the time correlated neutrons emitted by the spontaneous fissions of the even-even Pu isotopes in the presence of random neutron background, originating principally from (a,n) reactions in the material. The correlation technique discussed in this paper utilizes twofold neutron coincidence counting but the system is proposed to be enhanced for neutron multiplicity counting. A microcontroller based data acquisition system has been developed using a couple of fast FIFO 2kX9 bit memory ICs and a 16 bit counter for identifying time-correlated neutrons. Since the neutron pulses are arriving at a rapid rate, the incoming pulses are buffered in the FIFO and then transferred to PC by the microcontroller through the parallel port. The correlation analysis based on this time arrival information is done in the PC off-line. (author)
Two-Step Time of Arrival Estimation for Pulse-Based Ultra-Wideband Systems
Directory of Open Access Journals (Sweden)
H. Vincent Poor
2008-05-01
Full Text Available In cooperative localization systems, wireless nodes need to exchange accurate position-related information such as time-of-arrival (TOA and angle-of-arrival (AOA, in order to obtain accurate location information. One alternative for providing accurate position-related information is to use ultra-wideband (UWB signals. The high time resolution of UWB signals presents a potential for very accurate positioning based on TOA estimation. However, it is challenging to realize very accurate positioning systems in practical scenarios, due to both complexity/cost constraints and adverse channel conditions such as multipath propagation. In this paper, a two-step TOA estimation algorithm is proposed for UWB systems in order to provide accurate TOA estimation under practical constraints. In order to speed up the estimation process, the first step estimates a coarse TOA of the received signal based on received signal energy. Then, in the second step, the arrival time of the first signal path is estimated by considering a hypothesis testing approach. The proposed scheme uses low-rate correlation outputs and is able to perform accurate TOA estimation in reasonable time intervals. The simulation results are presented to analyze the performance of the estimator.
Uncertainty in Bus Arrival Time Predictions: Treating Heteroscedasticity With a Metamodel Approach
DEFF Research Database (Denmark)
O'Sullivan, Aidan; Pereira, Francisco Camara; Zhao, Jinhua
2016-01-01
Arrival time predictions for the next available bus or train are a key component of modern traveler information systems (TISs). A great deal of research has been conducted within the intelligent transportation system community in developing an assortment of different algorithms that seek...... sources. In this paper, we tackle the issue of uncertainty in bus arrival time predictions using an alternative approach. Rather than endeavor to develop a superior method for prediction, we take existing predictions from a TIS and treat the algorithm generating them as a black box. The presence...... of heteroscedasticity in the predictions is demonstrated and then a metamodel approach is deployed, which augments existing predictive systems using quantile regression to place bounds on the associated error. As a case study, this approach is applied to data from a real-world TIS in Boston. This method allows bounds...
AIMBAT: A Python/Matplotlib Tool for Measuring Teleseismic Arrival Times
Lou, X.; van der Lee, S.; Lloyd, S.
2013-12-01
Python is an open-source, platform-independent, and object-oriented scripting language. It became more popular in the seismologist community since the appearance of ObsPy (Beyreuther et al. 2010, Megies et al. 2011), which provides a powerful framework for seismic data access and processing. This study introduces a new Python-based tool named AIMBAT (Automated and Interactive Measurement of Body-wave Arrival Times) for measuring teleseismic body-wave arrival times on large-scale seismic event data (Lou et al. 2013). Compared to ObsPy, AIMBAT is a lighter tool that is more focused on a particular aspect of seismic data processing. It originates from the widely used MCCC (Multi-Channel Cross-Correlation) method developed by VanDecar and Crosson (1990). On top of the original MCCC procedure, AIMBAT is automated in initial phase picking and is interactive in quality control. The core cross-correlation function is implemented in Fortran to boost up performance in addition to Python. The GUI (graphical user interface) of AIMBAT depends on Matplotlib's GUI-neutral widgets and event-handling API. A number of sorting and (de)selecting options are designed to facilitate the quality control of seismograms. By using AIMBAT, both relative and absolute teleseismic body-wave arrival times are measured. AIMBAT significantly improves efficiency and quality of the measurements. User interaction is needed only to pick the target phase arrival and to set a time window on the array stack. The package is easy to install and use, open-source, and is publicly available. Graphical user interface of AIMBAT.
Paouris, Evangelos; Mavromichalaki, Helen
2017-12-01
In a previous work (Paouris and Mavromichalaki in Solar Phys. 292, 30, 2017), we presented a total of 266 interplanetary coronal mass ejections (ICMEs) with as much information as possible. We developed a new empirical model for estimating the acceleration of these events in the interplanetary medium from this analysis. In this work, we present a new approach on the effective acceleration model (EAM) for predicting the arrival time of the shock that preceds a CME, using data of a total of 214 ICMEs. For the first time, the projection effects of the linear speed of CMEs are taken into account in this empirical model, which significantly improves the prediction of the arrival time of the shock. In particular, the mean value of the time difference between the observed time of the shock and the predicted time was equal to +3.03 hours with a mean absolute error (MAE) of 18.58 hours and a root mean squared error (RMSE) of 22.47 hours. After the improvement of this model, the mean value of the time difference is decreased to -0.28 hours with an MAE of 17.65 hours and an RMSE of 21.55 hours. This improved version was applied to a set of three recent Earth-directed CMEs reported in May, June, and July of 2017, and we compare our results with the values predicted by other related models.
3D elastic full waveform inversion using P-wave excitation amplitude: Application to OBC field data
Oh, Juwon; Kalita, Mahesh; Alkhalifah, Tariq Ali
2017-01-01
We propose an efficient elastic full waveform inversion (FWI) based on the P-wave excitation amplitude (maximum energy arrival) approximation in the source wavefields. Because, based on the P-wave excitation approximation (ExA), the gradient direction is approximated by the cross-correlation of source and receiver wavefields at only excitation time, it estimates the gradient direction faster than its conventional counterpart. In addition to this computational speedup, the P-wave excitation approximation automatically ignores SP and SS correlations in the approximated gradient direction. In elastic FWI for ocean bottom cable (OBC) data, the descent direction for the S-wave velocity is often degraded by undesired long-wavelength features from the SS correlation. For this reason, the P-wave excitation approach increases the convergence rate of multi-parameter FWI compared to the conventional approach. The modified 2D Marmousi model with OBC acquisition is used to verify the differences between the conventional method and ExA. Finally, the feasibility of the proposed method is demonstrated on a real OBC data from North Sea.
3D elastic full waveform inversion using P-wave excitation amplitude: Application to OBC field data
Oh, Juwon
2017-12-05
We propose an efficient elastic full waveform inversion (FWI) based on the P-wave excitation amplitude (maximum energy arrival) approximation in the source wavefields. Because, based on the P-wave excitation approximation (ExA), the gradient direction is approximated by the cross-correlation of source and receiver wavefields at only excitation time, it estimates the gradient direction faster than its conventional counterpart. In addition to this computational speedup, the P-wave excitation approximation automatically ignores SP and SS correlations in the approximated gradient direction. In elastic FWI for ocean bottom cable (OBC) data, the descent direction for the S-wave velocity is often degraded by undesired long-wavelength features from the SS correlation. For this reason, the P-wave excitation approach increases the convergence rate of multi-parameter FWI compared to the conventional approach. The modified 2D Marmousi model with OBC acquisition is used to verify the differences between the conventional method and ExA. Finally, the feasibility of the proposed method is demonstrated on a real OBC data from North Sea.
Arrival-time picking method based on approximate negentropy for microseismic data
Li, Yue; Ni, Zhuo; Tian, Yanan
2018-05-01
Accurate and dependable picking of the first arrival time for microseismic data is an important part in microseismic monitoring, which directly affects analysis results of post-processing. This paper presents a new method based on approximate negentropy (AN) theory for microseismic arrival time picking in condition of much lower signal-to-noise ratio (SNR). According to the differences in information characteristics between microseismic data and random noise, an appropriate approximation of negentropy function is selected to minimize the effect of SNR. At the same time, a weighted function of the differences between maximum and minimum value of AN spectrum curve is designed to obtain a proper threshold function. In this way, the region of signal and noise is distinguished to pick the first arrival time accurately. To demonstrate the effectiveness of AN method, we make many experiments on a series of synthetic data with different SNR from -1 dB to -12 dB and compare it with previously published Akaike information criterion (AIC) and short/long time average ratio (STA/LTA) methods. Experimental results indicate that these three methods can achieve well picking effect when SNR is from -1 dB to -8 dB. However, when SNR is as low as -8 dB to -12 dB, the proposed AN method yields more accurate and stable picking result than AIC and STA/LTA methods. Furthermore, the application results of real three-component microseismic data also show that the new method is superior to the other two methods in accuracy and stability.
Fleischman, Ross J.; Lundquist, Mark; Jui, Jonathan; Newgard, Craig D.; Warden, Craig
2014-01-01
Objective To derive and validate a model that accurately predicts ambulance arrival time that could be implemented as a Google Maps web application. Methods This was a retrospective study of all scene transports in Multnomah County, Oregon, from January 1 through December 31, 2008. Scene and destination hospital addresses were converted to coordinates. ArcGIS Network Analyst was used to estimate transport times based on street network speed limits. We then created a linear regression model to improve the accuracy of these street network estimates using weather, patient characteristics, use of lights and sirens, daylight, and rush-hour intervals. The model was derived from a 50% sample and validated on the remainder. Significance of the covariates was determined by p times recorded by computer-aided dispatch. We then built a Google Maps-based web application to demonstrate application in real-world EMS operations. Results There were 48,308 included transports. Street network estimates of transport time were accurate within 5 minutes of actual transport time less than 16% of the time. Actual transport times were longer during daylight and rush-hour intervals and shorter with use of lights and sirens. Age under 18 years, gender, wet weather, and trauma system entry were not significant predictors of transport time. Our model predicted arrival time within 5 minutes 73% of the time. For lights and sirens transports, accuracy was within 5 minutes 77% of the time. Accuracy was identical in the validation dataset. Lights and sirens saved an average of 3.1 minutes for transports under 8.8 minutes, and 5.3 minutes for longer transports. Conclusions An estimate of transport time based only on a street network significantly underestimated transport times. A simple model incorporating few variables can predict ambulance time of arrival to the emergency department with good accuracy. This model could be linked to global positioning system data and an automated Google Maps web
Ready...go: Amplitude of the FMRI signal encodes expectation of cue arrival time.
Directory of Open Access Journals (Sweden)
Xu Cui
2009-08-01
Full Text Available What happens when the brain awaits a signal of uncertain arrival time, as when a sprinter waits for the starting pistol? And what happens just after the starting pistol fires? Using functional magnetic resonance imaging (fMRI, we have discovered a novel correlate of temporal expectations in several brain regions, most prominently in the supplementary motor area (SMA. Contrary to expectations, we found little fMRI activity during the waiting period; however, a large signal appears after the "go" signal, the amplitude of which reflects learned expectations about the distribution of possible waiting times. Specifically, the amplitude of the fMRI signal appears to encode a cumulative conditional probability, also known as the cumulative hazard function. The fMRI signal loses its dependence on waiting time in a "countdown" condition in which the arrival time of the go cue is known in advance, suggesting that the signal encodes temporal probabilities rather than simply elapsed time. The dependence of the signal on temporal expectation is present in "no-go" conditions, demonstrating that the effect is not a consequence of motor output. Finally, the encoding is not dependent on modality, operating in the same manner with auditory or visual signals. This finding extends our understanding of the relationship between temporal expectancy and measurable neural signals.
A New Tool for CME Arrival Time Prediction using Machine Learning Algorithms: CAT-PUMA
Liu, Jiajia; Ye, Yudong; Shen, Chenglong; Wang, Yuming; Erdélyi, Robert
2018-03-01
Coronal mass ejections (CMEs) are arguably the most violent eruptions in the solar system. CMEs can cause severe disturbances in interplanetary space and can even affect human activities in many aspects, causing damage to infrastructure and loss of revenue. Fast and accurate prediction of CME arrival time is vital to minimize the disruption that CMEs may cause when interacting with geospace. In this paper, we propose a new approach for partial-/full halo CME Arrival Time Prediction Using Machine learning Algorithms (CAT-PUMA). Via detailed analysis of the CME features and solar-wind parameters, we build a prediction engine taking advantage of 182 previously observed geo-effective partial-/full halo CMEs and using algorithms of the Support Vector Machine. We demonstrate that CAT-PUMA is accurate and fast. In particular, predictions made after applying CAT-PUMA to a test set unknown to the engine show a mean absolute prediction error of ∼5.9 hr within the CME arrival time, with 54% of the predictions having absolute errors less than 5.9 hr. Comparisons with other models reveal that CAT-PUMA has a more accurate prediction for 77% of the events investigated that can be carried out very quickly, i.e., within minutes of providing the necessary input parameters of a CME. A practical guide containing the CAT-PUMA engine and the source code of two examples are available in the Appendix, allowing the community to perform their own applications for prediction using CAT-PUMA.
THE NANOGRAV NINE-YEAR DATA SET: EXCESS NOISE IN MILLISECOND PULSAR ARRIVAL TIMES
Energy Technology Data Exchange (ETDEWEB)
Lam, M. T.; Jones, M. L.; McLaughlin, M. A.; Pennucci, T. T. [Department of Physics, West Virginia University, White Hall, Morgantown, WV 26506 (United States); Cordes, J. M.; Chatterjee, S. [Department of Astronomy and Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14853 (United States); Arzoumanian, Z. [Center for Research and Exploration in Space Science and Technology and X-Ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Crowter, K.; Fonseca, E.; Gonzalez, M. E. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Demorest, P. B. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM, 87801 (United States); Dolch, T. [Department of Physics, Hillsdale College, 33 E. College Street, Hillsdale, MI 49242 (United States); Ellis, J. A [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena CA, 91109 (United States); Ferdman, R. D. [Department of Physics, McGill University, 3600 rue Universite, Montreal, QC H3A 2T8 (Canada); Jones, G. [Department of Physics, Columbia University, 550 W. 120th Street, New York, NY 10027 (United States); Levin, L. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Madison, D. R.; Ransom, S. M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Nice, D. J. [Department of Physics, Lafayette College, Easton, PA 18042 (United States); Shannon, R. M., E-mail: michael.lam@mail.wvu.edu [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Box 76, Epping NSW 1710 (Australia); and others
2017-01-01
Gravitational wave (GW) astronomy using a pulsar timing array requires high-quality millisecond pulsars (MSPs), correctable interstellar propagation delays, and high-precision measurements of pulse times of arrival. Here we identify noise in timing residuals that exceeds that predicted for arrival time estimation for MSPs observed by the North American Nanohertz Observatory for Gravitational Waves. We characterize the excess noise using variance and structure function analyses. We find that 26 out of 37 pulsars show inconsistencies with a white-noise-only model based on the short timescale analysis of each pulsar, and we demonstrate that the excess noise has a red power spectrum for 15 pulsars. We also decompose the excess noise into chromatic (radio-frequency-dependent) and achromatic components. Associating the achromatic red-noise component with spin noise and including additional power-spectrum-based estimates from the literature, we estimate a scaling law in terms of spin parameters (frequency and frequency derivative) and data-span length and compare it to the scaling law of Shannon and Cordes. We briefly discuss our results in terms of detection of GWs at nanohertz frequencies.
Luo, B.; Bu, X.; Liu, S.; Gong, J.
2017-12-01
Coronal holes are sources of high-speed steams (HSS) of solar wind. When coronal holes appear at mid/low latitudes on the Sun, consequential HSSs may impact Earth and cause recurrent geospace environment disturbances, such as geomagnetic storms, relativistic electron enhancements at the geosynchronous orbit, and thermosphere density enhancements. Thus, it is of interests for space weather forecasters to predict when (arrival times), how long (time durations), and how severe (intensities) HSSs may impact Earth when they notice coronal holes on the sun and are anticipating their geoeffectiveness. In this study, relationship between coronal holes and high speed streams will be statistically investigated. Several coronal hole parameters, including passage times of solar central meridian, coronal hole longitudinal widths, intensities reflected by mean brightness, are derived using Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images for years 2011 to 2016. These parameters will be correlated with in-situ solar wind measurements measured at the L1 point by the ACE spacecraft, which can give some results that are useful for space weather forecaster in predicting the arrival times, durations, and intensities of coronal hole high-speed streams in about 3 days advance.
The Effect of Integration Policies on the Time until Regular Employment of Newly Arrived Immigrants:
DEFF Research Database (Denmark)
Clausen, Jens; Heinesen, Eskil; Hummelgaard, Hans
We analyse the effect of active labour-market programmes on the hazard rate into regular employment for newly arrived immigrants using the timing-of-events duration model. We take account of language course participation and progression in destination country language skills. We use rich...... administrative data from Denmark. We find substantial lock-in effects of participation in active labour-market programmes. Post programme effects on the hazard rate to regular employment are significantly positive for wage subsidy programmes, but not for other types of programmes. For language course...... participants, improvement in language proficiency has significant and substantial positive effects on the hazard rate to employment....
Prediction of the Critical Curvature for LX-17 with the Time of Arrival Data from DNS
Energy Technology Data Exchange (ETDEWEB)
Yao, Jin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fried, Laurence E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Moss, William C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2017-01-10
We extract the detonation shock front velocity, curvature and acceleration from time of arrival data measured at grid points from direct numerical simulations of a 50mm rate-stick lit by a disk-source, with the ignition and growth reaction model and a JWL equation of state calibrated for LX-17. We compute the quasi-steady (D, κ) relation based on the extracted properties and predicted the critical curvatures of LX-17. We also proposed an explicit formula that contains the failure turning point, obtained from optimization for the (D, κ) relation of LX-17.
Directory of Open Access Journals (Sweden)
R. Tondi
2004-06-01
Full Text Available We performed an analysis of refraction data recorded in Italy since 1968 in the frame of the numerous deep seismic sounding and wide-angle reflection/refraction projects. The aims of this study are to construct a parametric database including the recording geometric information relative to each profile, the phase pickings and the results of some kinematic analyses performed on the data, and to define a reference 1D velocity model for the Italian territory from all the available refraction data. As concerns the first goal, for each seismic section we picked the P-wave first-arrival-times, evaluated the uncertainties of the arrival-times pickings and determined from each travel time-offset curve the 1D velocity model. The study was performed on 419 seismic sections. Picking was carried out manually by an algorithm which includes the computation of three picking functions and the picking- error estimation. For each of the travel time-offset curves a 1D velocity model has been calculated. Actually, the 1D velocity-depth functions were estimated in three different ways which assume: a constant velocitygradient model, a varying velocity-gradient model and a layered model. As regards the second objective of this work, a mean 1D velocity model for the Italian crust was defined and compared with those used for earthquake hypocentre locations and seismic tomographic studies by different institutions operating in the Italian area, to assess the significance of the model obtained. This model can be used in future works as input for a next joint tomographic inversion of active and passive seismic data.
Sanders, Geoff; Sinclair, Kamila
2011-12-01
We report two Internet studies that investigated sex differences in the accuracy and precision of judging time to arrival. We used accuracy to mean the ability to match the actual time to arrival and precision to mean the consistency with which each participant made their judgments. Our task was presented as a computer game in which a toy UFO moved obliquely towards the participant through a virtual three-dimensional space on route to a docking station. The UFO disappeared before docking and participants pressed their space bar at the precise moment they thought the UFO would have docked. Study 1 showed it was possible to conduct quantitative studies of spatiotemporal judgments in virtual reality via the Internet and confirmed reports that men are more accurate because women underestimate, but found no difference in precision measured as intra-participant variation. Study 2 repeated Study 1 with five additional presentations of one condition to provide a better measure of precision. Again, men were more accurate than women but there were no sex differences in precision. However, within the coincidence-anticipation timing (CAT) literature, of those studies that report sex differences, a majority found that males are both more accurate and more precise than females. Noting that many CAT studies report no sex differences, we discuss appropriate interpretations of such null findings. While acknowledging that CAT performance may be influenced by experience we suggest that the sex difference may have originated among our ancestors with the evolutionary selection of men for hunting and women for gathering.
Zhou, Haiming; Hanson, Timothy; Knapp, Roland
2015-12-01
The global emergence of Batrachochytrium dendrobatidis (Bd) has caused the extinction of hundreds of amphibian species worldwide. It has become increasingly important to be able to precisely predict time to Bd arrival in a population. The data analyzed herein present a unique challenge in terms of modeling because there is a strong spatial component to Bd arrival time and the traditional proportional hazards assumption is grossly violated. To address these concerns, we develop a novel marginal Bayesian nonparametric survival model for spatially correlated right-censored data. This class of models assumes that the logarithm of survival times marginally follow a mixture of normal densities with a linear-dependent Dirichlet process prior as the random mixing measure, and their joint distribution is induced by a Gaussian copula model with a spatial correlation structure. To invert high-dimensional spatial correlation matrices, we adopt a full-scale approximation that can capture both large- and small-scale spatial dependence. An efficient Markov chain Monte Carlo algorithm with delayed rejection is proposed for posterior computation, and an R package spBayesSurv is provided to fit the model. This approach is first evaluated through simulations, then applied to threatened frog populations in Sequoia-Kings Canyon National Park. © 2015, The International Biometric Society.
Energy Technology Data Exchange (ETDEWEB)
Cho, Seung Hyun; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)
2008-12-15
Guided wave technology is advantageous for fast inspection of pipe wall thinning since the guided wave propagates long distance. In this investigation, the method to evaluate gradual wall thinning in a pipe based on the arrival time delay with magnetostrictive patch transducers is presented. Low frequency A0 Lamb waves were generated and measured by the present transducer and it was applied to arrival time delay measurement experiments on a test pipe having gradual wall thinnings artificially manufactured. From experiments, consistent results that wall thinning increases the arrival time delay of A0 waves were obtained. Consequently, the feasibility of the magnetostrictive patch transducers to evaluate wall thinning was verified
International Nuclear Information System (INIS)
Cho, Seung Hyun; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok
2008-01-01
Guided wave technology is advantageous for fast inspection of pipe wall thinning since the guided wave propagates long distance. In this investigation, the method to evaluate gradual wall thinning in a pipe based on the arrival time delay with magnetostrictive patch transducers is presented. Low frequency A0 Lamb waves were generated and measured by the present transducer and it was applied to arrival time delay measurement experiments on a test pipe having gradual wall thinnings artificially manufactured. From experiments, consistent results that wall thinning increases the arrival time delay of A0 waves were obtained. Consequently, the feasibility of the magnetostrictive patch transducers to evaluate wall thinning was verified
International Nuclear Information System (INIS)
Badea, A.F.; Brancus, I.M.; Haeusler, R.; Rebel, H.
2000-01-01
The muon arrival time distributions of Extensive Air Showers (EAS) have been studied in KASCADE experiment by data collected in the period October 1997 - April 1999 with more than 3.4 millions of reconstructed showers. The radial distance of the shower center from the central detector has been selected smaller than 110 m. The experimental muon arrival time distributions are compared with simulations of the air shower development, calculated with the Monte Carlo air shower simulation program CORSIKA. The actual calculations are based on the QGSJET model and cover an energy range of 5·10 14 - 3.06·10 16 eV (divided in 7 overlapping energy bins) and a zenith angle range of 0 angle - 40 angle. They are performed for three mass groups: H = light group, O = CNO group, Fe = heavy group) with an energy distribution of a spectral index of -2.7. The simulations comprise a set of ≅ 2000$ showers for each case, except for the bins of the highest energies (6.51·10 15 - 1.82·10 16 eV with ≅1000$ simulated showers and 1.09·10 16 - 3.06·10 16 eV with ≅ 500 simulated showers). The response of the KASCADE detector system and the timing qualities have been simulated using the CRES program, dedicatedly developed by the KASCADE group on the basis of the GEANT code. The particles of the simulated EAS are tracked through the detector setup and the timing response of the detectors are recorded for various core distances from the central detector facilities. Particularly, it should be noted that the timing depends on the energy deposit in the scintillation detectors and on the multiplicities of the muon samples spanning the arrival time distributions of the single EAS. Such effects slightly distorts the measured time distributions and have been corrected by introducing a corresponding correction procedure. The dependence of the experimental and simulated median time values on the N μ tr range, as being proportional to the primary energy, is presented. The good agreement of the
Positioning performance analysis of the time sum of arrival algorithm with error features
Gong, Feng-xun; Ma, Yan-qiu
2018-03-01
The theoretical positioning accuracy of multilateration (MLAT) with the time difference of arrival (TDOA) algorithm is very high. However, there are some problems in practical applications. Here we analyze the location performance of the time sum of arrival (TSOA) algorithm from the root mean square error ( RMSE) and geometric dilution of precision (GDOP) in additive white Gaussian noise (AWGN) environment. The TSOA localization model is constructed. Using it, the distribution of location ambiguity region is presented with 4-base stations. And then, the location performance analysis is started from the 4-base stations with calculating the RMSE and GDOP variation. Subsequently, when the location parameters are changed in number of base stations, base station layout and so on, the performance changing patterns of the TSOA location algorithm are shown. So, the TSOA location characteristics and performance are revealed. From the RMSE and GDOP state changing trend, the anti-noise performance and robustness of the TSOA localization algorithm are proved. The TSOA anti-noise performance will be used for reducing the blind-zone and the false location rate of MLAT systems.
National Research Council Canada - National Science Library
Streight, David
1997-01-01
.... The Applied Research Lab at the University of Texas at Austin (ARL:UT) has developed a prototype TDOA system, the Carry-on Multi-platform GPS Assisted Time Difference of Arrival System for the Naval Information Warfare Activity...
Seismicity and arrival-time residuals from the Victoria Earthquake of June 9, 1980
Energy Technology Data Exchange (ETDEWEB)
Wong, V.; Frez, J.
1981-01-01
Hypocenter distribution in space and time of the aftershock activity from the Victoria Earthquake of June 9, 1980 was studied. It was concluded that the main event excited aftershocks in several pre-existing nests at the northwest end of the Cerro Prieto Fault, but no significant activity occurred at the immediate neighborhood of the main event. The depth of the aftershocks increases with the distance from the northwest end of the fault and this feature might be related with the higher temperatures and the spreading center located between the ends of the Imperial and Cerro Prieto Faults. The significance of the arrival-times residuals for local and regional stations is discussed both for P and S-waves and the importance of obtaining station corrections is emphasized. The non-uniqueness in determining a structure which minimizes the residuals is illustrated. Two different structures which satisfy the local data are presented.
Becker, Peter H.; Dittmann, Tobias; Ludwigs, Jan-Dieter; Limmer, Bente; Ludwig, Sonja C.; Bauch, Christina; Braasch, Alexander; Wendeln, Helmut
2008-01-01
In long-lived vertebrates, individuals generally visit potential breeding areas or populations during one or more seasons before reproducing for the first time. During these years of prospecting, they select a future breeding site, colony, or mate and improve various skills and their physical condition to meet the requirements of reproduction. One precondition of successful reproduction is arrival in time on the breeding grounds. Here, we study the intricate links among the date of initial spring arrival, body mass, sex, and the age of first breeding in the common tern Sterna hirundo, a long-lived migratory colonial seabird. The study is based on a unique, individual-based, long-term dataset of sexed birds, marked with transponders, which allow recording their individual arrival, overall attendance, and clutch initiation remotely and automatically year by year over the entire lifetime at the natal colony site. We show that the seasonal date of initial arrival at the breeding grounds predicts the individual age at first reproduction, which mostly occurs years later. Late first-time arrivals remain delayed birds throughout subsequent years. Our findings reveal that timing of arrival at the site of reproduction and timing of reproduction itself are coherent parameters of individual quality, which are linked with the prospects of the breeding career and may have consequences for fitness. PMID:18711134
Spectral encoding method for measuring the relative arrival time between x-ray/optical pulses
International Nuclear Information System (INIS)
Bionta, M. R.; Hartmann, N.; Weaver, M.; French, D.; Glownia, J. M.; Bostedt, C.; Chollet, M.; Ding, Y.; Fritz, D. M.; Fry, A. R.; Krzywinski, J.; Lemke, H. T.; Messerschmidt, M.; Schorb, S.; Zhu, D.; White, W. E.; Nicholson, D. J.; Cryan, J. P.; Baker, K.; Kane, D. J.
2014-01-01
The advent of few femtosecond x-ray light sources brings promise of x-ray/optical pump-probe experiments that can measure chemical and structural changes in the 10–100 fs time regime. Widely distributed timing systems used at x-ray Free-Electron Laser facilities are typically limited to above 50 fs fwhm jitter in active x-ray/optical synchronization. The approach of single-shot timing measurements is used to sort results in the event processing stage. This has seen wide use to accommodate the insufficient precision of active stabilization schemes. In this article, we review the current technique for “measure-and-sort” at the Linac Coherent Light Source at the SLAC National Accelerator Laboratory. The relative arrival time between an x-ray pulse and an optical pulse is measured near the experimental interaction region as a spectrally encoded cross-correlation signal. The cross-correlation provides a time-stamp for filter-and-sort algorithms used for real-time sorting. Sub-10 fs rms resolution is common in this technique, placing timing precision at the same scale as the duration of the shortest achievable x-ray pulses
Directory of Open Access Journals (Sweden)
Michael Short
2017-07-01
Full Text Available Embedded systems consist of one or more processing units which are completely encapsulated by the devices under their control, and they often have stringent timing constraints associated with their functional specification. Previous research has considered the performance of different types of task scheduling algorithm and developed associated timing analysis techniques for such systems. Although preemptive scheduling techniques have traditionally been favored, rapid increases in processor speeds combined with improved insights into the behavior of non-preemptive scheduling techniques have seen an increased interest in their use for real-time applications such as multimedia, automation and control. However when non-preemptive scheduling techniques are employed there is a potential lack of error confinement should any timing errors occur in individual software tasks. In this paper, the focus is upon adding fault tolerance in systems using non-preemptive deadline-driven scheduling. Schedulability conditions are derived for fault-tolerant periodic and sporadic task sets experiencing bounded error arrivals under non-preemptive deadline scheduling. A timing analysis algorithm is presented based upon these conditions and its run-time properties are studied. Computational experiments show it to be highly efficient in terms of run-time complexity and competitive ratio when compared to previous approaches.
Han, Zifa; Leung, Chi Sing; So, Hing Cheung; Constantinides, Anthony George
2017-08-15
A commonly used measurement model for locating a mobile source is time-difference-of-arrival (TDOA). As each TDOA measurement defines a hyperbola, it is not straightforward to compute the mobile source position due to the nonlinear relationship in the measurements. This brief exploits the Lagrange programming neural network (LPNN), which provides a general framework to solve nonlinear constrained optimization problems, for the TDOA-based localization. The local stability of the proposed LPNN solution is also analyzed. Simulation results are included to evaluate the localization accuracy of the LPNN scheme by comparing with the state-of-the-art methods and the optimality benchmark of Cramér-Rao lower bound.
Pickup design for high bandwidth bunch arrival-time monitors in free-electron lasers
Energy Technology Data Exchange (ETDEWEB)
Angelovski, Aleksandar; Penirschke, Andreas; Jakoby, Rolf [TU Darmstadt (Germany). Institut fuer Mikrowellentechnik und Photonik; Kuhl, Alexander; Schnepp, Sascha [TU Darmstadt (Germany). Graduate School of Computational Engineering; Bock, Marie Kristin; Bousonville, Michael; Schlarb, Holger [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Weiland, Thomas [TU Darmstadt (Germany). Institut fuer Theorie Elektromagnetischer Felder
2012-07-01
The increased demands for low bunch charge operation mode in the free-electron lasers (FELs) require an upgrade of the existing synchronization equipment. As a part of the laser-based synchronization system, the bunch arrival-time monitors (BAMs) should have a sub-10 femtosecond precision for high and low bunch charge operation. In order to fulfill the resolution demands for both modes of operation, the bandwidth of such a BAM should be increased up to a cutoff frequency of 40 GHz. In this talk, we present the design and the realization of high bandwidth cone-shaped pickup electrodes as a part of the BAM for the FEL in Hamburg (FLASH) and the European X-ray free-electron laser (European XFEL). The proposed pickup was simulated with CST STUDIO SUITE, and a non-hermetic model was built up for radio frequency (rf) measurements.
DEFF Research Database (Denmark)
Bech, Camilla Nørgaard; Brabrand, Mikkel; Mikkelsen, Søren
2018-01-01
, 0-2 day, 3-7 day and 8-30 day mortality. The degree of acuteness at arrival defined by urgency-level, physician-assisted transfer to the Emergency Department and abnormal vital parameters are associated with 0-2 day mortality. High temperature at arrival shows no association in either mortality...
41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?
2010-07-01
... departure/arrival dates and times on my travel claim? 301-11.10 Section 301-11.10 Public Contracts and... dates and times on my travel claim? You must record the date of departure from, and arrival at, the... visited. You do not have to record departure/arrival times, but you must annotate your travel claim when...
Depth variations of P-wave azimuthal anisotropy beneath East Asia
Wei, W.; Zhao, D.; Xu, J.
2017-12-01
We present a new P-wave anisotropic tomographic model beneath East Asia by inverting a total of 1,488,531 P wave arrival-time data recorded by the regional seismic networks in East Asia and temporary seismic arrays deployed on the Tibetan Plateau. Our results provide important new insights into the subducting Indian, Pacific and Philippine Sea plates and mantle dynamics in East Asia. Our tomographic images show that the northern limit of the subducting Indian plate has reached the Jinsha River suture in eastern Tibet. A striking variation of P-wave azimuthal anisotropy is revealed in the Indian lithosphere: the fast velocity direction (FVD) is NE-SW beneath the Indian continent, whereas the FVD is arc parallel beneath the Himalaya and Tibetan Plateau, which may reflect re-orientation of minerals due to lithospheric extension, in response to the India-Eurasia collision. The FVD in the subducting Philippine Sea plate beneath the Ryukyu arc is NE-SW(trench parallel), which is consistent with the spreading direction of the West Philippine Basin during its initial opening stage, suggesting that it may reflect the fossil anisotropy. A circular pattern of FVDs is revealed around the Philippine Sea slab beneath SE China. We suggest that it reflects asthenospheric strain caused by toroidal mantle flow around the edge of the subducting slab. We find a striking variation of the FVD with depth in the subducting Pacific slab beneath the Northeast Japan arc. It may be caused by slab dehydration that changed elastic properties of the slab with depth. The FVD in the mantle wedge beneath the Northeast Japan and Ryukyu arcs is trench normal, which reflects subduction-induced convection. Beneath the Kuril and Izu-Bonin arcs where oblique subduction occurs, the FVD in the mantle wedge is nearly normal to the moving direction of the downgoing Pacific plate, suggesting that the oblique subduction together with the complex slab morphology have disturbed the mantle flow.
Rapid estimation of earthquake magnitude from the arrival time of the peak high‐frequency amplitude
Noda, Shunta; Yamamoto, Shunroku; Ellsworth, William L.
2016-01-01
We propose a simple approach to measure earthquake magnitude M using the time difference (Top) between the body‐wave onset and the arrival time of the peak high‐frequency amplitude in an accelerogram. Measured in this manner, we find that Mw is proportional to 2logTop for earthquakes 5≤Mw≤7, which is the theoretical proportionality if Top is proportional to source dimension and stress drop is scale invariant. Using high‐frequency (>2 Hz) data, the root mean square (rms) residual between Mw and MTop(M estimated from Top) is approximately 0.5 magnitude units. The rms residuals of the high‐frequency data in passbands between 2 and 16 Hz are uniformly smaller than those obtained from the lower‐frequency data. Top depends weakly on epicentral distance, and this dependence can be ignored for distances earthquake produces a final magnitude estimate of M 9.0 at 120 s after the origin time. We conclude that Top of high‐frequency (>2 Hz) accelerograms has value in the context of earthquake early warning for extremely large events.
International Nuclear Information System (INIS)
Kramme, Johanna; Diehl, Volker; Madai, Vince I.; Sobesky, Jan; Guenther, Matthias
2015-01-01
The improvement in Arterial Spin Labeling (ASL) perfusion quantification, especially for delayed bolus arrival times (BAT), with an acquisition redistribution scheme mitigating the T1 decay of the label in multi-TI ASL measurements is investigated. A multi inflow time (TI) 3D-GRASE sequence is presented which adapts the distribution of acquisitions accordingly, by keeping the scan time constant. The MR sequence increases the number of averages at long TIs and decreases their number at short TIs and thus compensating the T1 decay of the label. The improvement of perfusion quantification is evaluated in simulations as well as in-vivo in healthy volunteers and patients with prolonged BATs due to age or steno-occlusive disease. The improvement in perfusion quantification depends on BAT. At healthy BATs the differences are small, but become larger for longer BATs typically found in certain diseases. The relative error of perfusion is improved up to 30% at BATs > 1500 ms in comparison to the standard acquisition scheme. This adapted acquisition scheme improves the perfusion measurement in comparison to standard multi-TI ASL implementations. It provides relevant benefit in clinical conditions that cause prolonged BATs and is therefore of high clinical relevance for neuroimaging of steno-occlusive diseases.
The effect of patients’ time of arrival at the hospital on the rate of Thrombolytic therapy
Directory of Open Access Journals (Sweden)
Toba Kazemi
2013-01-01
Full Text Available The honorable editor-in-chief of the Journal of ARYA We read with interest the article of Dr. Maleki that has recently been published.1 We conducted a similar study in Birjand Vali-e-Asr Hospital in 2009-2010. This study was done on 125 patients with STEMI with a mean age of 59.2 ± 11.9 years. In this study, 65.6% of patients underwent thrombolytic therapy. This showed a crucial increase compared to the previous study in Birjand in 2003 that showed 17.3% of patients underwent thrombolytic therapy.2 Mean door to needle time was 74.8 ± 42.7 minutes (median 60 minutes. Thrombolytic therapy showed no difference for difference in sex (69.4% in males, and 51.9% in females, P = 0.08. However, in working staff (86.7% in employees, and 51.2% in farmers/workers, P = 0.003, in highly educated individuals (92.3% at university level, and 45.5% illiterate, P < 0.001, and in citizens (73.2% in urban, and 51.2% in rural citizens, P = 0.01 there was a higher percentage of thrombolytic therapy. The main reason for this difference between them is earlier arrival to the hospital since the onset of symptoms. The arrival time in the city's residents was 166.7 ± 179.6 minutes, but for villagers it was 221.6 ± 112 minutes (P = 0.001. Furthermore, the rate of thrombolytic therapy during the night was not significantly different compared to the rest of the day (73% during morning, 62.9% during afternoon, and 62.3% during night, P = 0.52. The patient's arrival time to the hospital at night was not different compared to the rest of the day (166.9 ± 174.7 minutes in the morning shift, and 148.2 ± 85.2 minutes during the night shift, P = 0.63. Visiting patients during the night shift was similar to other shifts; visit by intern was 12.3 ± 9.1 minutes during the morning shift, and 14.1 ± 9.3 minutes during the night shift (P = 0.73. The rate of thrombolytic therapy in our study was similar to the study by Dr. Maleki;1 however, door to needle time was longer. In our
Chen, Po-Fei; Huang, Bor-Shouh; Chiao, Ling-Yun
2011-01-01
Probing the lateral heterogeneity of the upper mantle seismic velocity structure beneath southern and central Taiwan is critical to understanding the local tectonics and orogeny. A linear broadband array that transects southern Taiwan, together with carefully selected teleseismic sources with the right azimuth provides useful constraints. They are capable of differentiating the lateral heterogeneity along the profile with systematic coverage of ray paths. We implement a scheme based on the genetic algorithm to simultaneously determine the relative delayed times of the teleseismic first arrivals of array data. The resulting patterns of the delayed times systematically vary as a function of the incident angle. Ray tracing attributes the observed variations to a high velocity anomaly dipping east in the mantle beneath the southeast of Taiwan. Combining the ray tracing analysis and a pseudo-spectral method to solve the 2-D wave propagations, we determine the extent of the anomaly that best fits the observations via the forward grid search. The east-dipping fast anomaly in the upper mantle beneath the southeast of Taiwan agrees with the results from several previous studies and indicates that the nature of the local ongoing arc-continent collision is likely characterized by the thin-skinned style.
Ishise, M.; Koketsu, K.; Miyake, H.; Oda, H.
2006-12-01
The Japan islands arc is located in the convergence zone of the North American (NA), Amurian (AM), Pacific (PAC) and Philippine Sea (PHS) plates, and its parts are exposed to various tectonic settings. For example, at the Kanto district in its central part, these four plates directly interact with each, so that disastrous future earthquakes are expected along the plate boundaries and within the inland areas. In order to understand this sort of complex tectonic setting, it is necessary to know the seismological structure in various perspectives. We investigate the seismic velocity structure beneath the Japan islands in view of P-wave anisotropy. We improved a hitherto-known P-wave tomography technique so that the 3-D structure of isotropic and anisotropic velocities and earthquake hypocenter locations are determined from P-wave arrival times of local earthquakes [Ishise and Oda, 2005]. In the tomography technique, P-wave anisotropy is assumed to hold hexagonal symmetry with horizontal symmetry axis. The P-wave arrival times used in this study are complied in the Japan University Network Earthquake Catalog. The results obtained are summarized as follows; (1) the upper crust anisotropy is governed by the present-day stress field arising from the interaction between the plates surrounding the Japan islands arc, (2) the mantle anisotropy is caused by the present-day mantle flow induced by slab subduction and continental plate motion, (3) the old PAC slab keeps its original slab anisotropy which was captured when the plate was formed, while the youngest part of the PHS slab has lost the original anisotropy during its subduction and has gained new anisotropy which is controlled by the present-day stress field. We also carried out a further study on high-resolution seismic tomography for understanding the specific characteristics of the Kanto district. We mostly focused on the elucidation of the dual subduction formed by the PHS and PAC slabs using seismological data
Su, Ho-Ming; Tsai, Wei-Chung; Lin, Tsung-Hsien; Hsu, Po-Chao; Lee, Wen-Hsien; Lin, Ming-Yen; Chen, Szu-Chia; Lee, Chee-Siong; Voon, Wen-Chol; Lai, Wen-Ter; Sheu, Sheng-Hsiung
2012-01-01
The P wave parameters measured by 12-lead electrocardiogram (ECG) are commonly used as noninvasive tools to assess for left atrial enlargement. There are limited studies to evaluate whether P wave parameters are independently associated with decline in renal function. Accordingly, the aim of this study is to assess whether P wave parameters are independently associated with progression to renal end point of ≥25% decline in estimated glomerular filtration rate (eGFR). This longitudinal study included 166 patients. The renal end point was defined as ≥25% decline in eGFR. We measured two ECG P wave parameters corrected by heart rate, i.e. corrected P wave dispersion (PWdisperC) and corrected P wave maximum duration (PWdurMaxC). Heart function and structure were measured from echocardiography. Clinical data, P wave parameters, and echocardiographic measurements were compared and analyzed. Forty-three patients (25.9%) reached renal end point. Kaplan-Meier curves for renal end point-free survival showed PWdisperC > median (63.0 ms) (log-rank P = 0.004) and PWdurMaxC > median (117.9 ms) (log-rank Pfunction decline.
P-wave velocity structure beneath the northern Antarctic Peninsula
Park, Y.; Kim, K.; Jin, Y.
2010-12-01
We have imaged tomographically the tree-dimensional velocity structure of the upper mantle beneath the northern Antarctic Peninsula using teleseismic P waves. The data came from the seven land stations of the Seismic Experiment in Patagonia and Antarctica (SEPA) campaigned during 1997-1999, a permanent IRIS/GSN station (PMSA), and 3 seismic stations installed at scientific bases, Esperanza (ESPZ), Jubany (JUBA), and King Sejong (KSJ), in South Shetland Islands. All of the seismic stations are located in coast area, and the signal to noise ratios (SNR) are very low. The P-wave model was inverted from 95 earthquakes resulting in 347 ray paths with P- and PKP-wave arrivals. The inverted model shows a strong low velocity anmaly beneath the Bransfield Strait, and a fast anomaly beneath the South Shetland Islands. The low velocity anomaly beneath the Bransfield might be due to a back arc extension, and the fast velocity anomaly beneath the South Shetland Islands could indicates the cold subducted slab.
Fault zone structure determined through the analysis of earthquake arrival times
Energy Technology Data Exchange (ETDEWEB)
Michelini, A.
1991-10-01
This thesis develops and applies a technique for the simultaneous determination of P and S wave velocity models and hypocenters from a set of arrival times. The velocity models are parameterized in terms of cubic B-splines basis functions which permit the retrieval of smooth models that can be used directly for generation of synthetic seismograms using the ray method. In addition, this type of smoothing limits the rise of instabilities related to the poor resolving power of the data. V{sub P}/V{sub S} ratios calculated from P and S models display generally instabilities related to the different ray-coverages of compressional and shear waves. However, V{sub P}/V{sub S} ratios are important for correct identification of rock types and this study introduces a new methodology based on adding some coupling (i.e., proportionality) between P and S models which stabilizes the V{sub P}/V{sub S} models around some average preset value determined from the data. Tests of the technique with synthetic data show that this additional coupling regularizes effectively the resulting models.
Fault zone structure determined through the analysis of earthquake arrival times
Energy Technology Data Exchange (ETDEWEB)
Michelini, Alberto [Univ. of California, Berkeley, CA (United States)
1991-10-01
This thesis develops and applies a technique for the simultaneous determination of P and S wave velocity models and hypocenters from a set of arrival times. The velocity models are parameterized in terms of cubic B-splines basis functions which permit the retrieval of smooth models that can be used directly for generation of synthetic seismograms using the ray method. In addition, this type of smoothing limits the rise of instabilities related to the poor resolving power of the data. V_{P}/V_{S} ratios calculated from P and S models display generally instabilities related to the different ray-coverages of compressional and shear waves. However, V_{P}/V_{S} ratios are important for correct identification of rock types and this study introduces a new methodology based on adding some coupling (i.e., proportionality) between P and S models which stabilizes the V_{P}/V_{S} models around some average preset value determined from the data. Tests of the technique with synthetic data show that this additional coupling regularizes effectively the resulting models.
Time difference of arrival estimation of microseismic signals based on alpha-stable distribution
Jia, Rui-Sheng; Gong, Yue; Peng, Yan-Jun; Sun, Hong-Mei; Zhang, Xing-Li; Lu, Xin-Ming
2018-05-01
Microseismic signals are generally considered to follow the Gauss distribution. A comparison of the dynamic characteristics of sample variance and the symmetry of microseismic signals with the signals which follow α-stable distribution reveals that the microseismic signals have obvious pulse characteristics and that the probability density curve of the microseismic signal is approximately symmetric. Thus, the hypothesis that microseismic signals follow the symmetric α-stable distribution is proposed. On the premise of this hypothesis, the characteristic exponent α of the microseismic signals is obtained by utilizing the fractional low-order statistics, and then a new method of time difference of arrival (TDOA) estimation of microseismic signals based on fractional low-order covariance (FLOC) is proposed. Upon applying this method to the TDOA estimation of Ricker wavelet simulation signals and real microseismic signals, experimental results show that the FLOC method, which is based on the assumption of the symmetric α-stable distribution, leads to enhanced spatial resolution of the TDOA estimation relative to the generalized cross correlation (GCC) method, which is based on the assumption of the Gaussian distribution.
Enhancing the estimation of blood pressure using pulse arrival time and two confounding factors
International Nuclear Information System (INIS)
Baek, Hyun Jae; Kim, Ko Keun; Kim, Jung Soo; Lee, Boreom; Park, Kwang Suk
2010-01-01
A new method of blood pressure (BP) estimation using multiple regression with pulse arrival time (PAT) and two confounding factors was evaluated in clinical and unconstrained monitoring situations. For the first analysis with clinical data, electrocardiogram (ECG), photoplethysmogram (PPG) and invasive BP signals were obtained by a conventional patient monitoring device during surgery. In the second analysis, ECG, PPG and non-invasive BP were measured using systems developed to obtain data under conditions in which the subject was not constrained. To enhance the performance of BP estimation methods, heart rate (HR) and arterial stiffness were considered as confounding factors in regression analysis. The PAT and HR were easily extracted from ECG and PPG signals. For arterial stiffness, the duration from the maximum derivative point to the maximum of the dicrotic notch in the PPG signal, a parameter called TDB, was employed. In two experiments that normally cause BP variation, the correlation between measured BP and the estimated BP was investigated. Multiple-regression analysis with the two confounding factors improved correlation coefficients for diastolic blood pressure and systolic blood pressure to acceptable confidence levels, compared to existing methods that consider PAT only. In addition, reproducibility for the proposed method was determined using constructed test sets. Our results demonstrate that non-invasive, non-intrusive BP estimation can be obtained using methods that can be applied in both clinical and daily healthcare situations
Enhancing the estimation of blood pressure using pulse arrival time and two confounding factors.
Baek, Hyun Jae; Kim, Ko Keun; Kim, Jung Soo; Lee, Boreom; Park, Kwang Suk
2010-02-01
A new method of blood pressure (BP) estimation using multiple regression with pulse arrival time (PAT) and two confounding factors was evaluated in clinical and unconstrained monitoring situations. For the first analysis with clinical data, electrocardiogram (ECG), photoplethysmogram (PPG) and invasive BP signals were obtained by a conventional patient monitoring device during surgery. In the second analysis, ECG, PPG and non-invasive BP were measured using systems developed to obtain data under conditions in which the subject was not constrained. To enhance the performance of BP estimation methods, heart rate (HR) and arterial stiffness were considered as confounding factors in regression analysis. The PAT and HR were easily extracted from ECG and PPG signals. For arterial stiffness, the duration from the maximum derivative point to the maximum of the dicrotic notch in the PPG signal, a parameter called TDB, was employed. In two experiments that normally cause BP variation, the correlation between measured BP and the estimated BP was investigated. Multiple-regression analysis with the two confounding factors improved correlation coefficients for diastolic blood pressure and systolic blood pressure to acceptable confidence levels, compared to existing methods that consider PAT only. In addition, reproducibility for the proposed method was determined using constructed test sets. Our results demonstrate that non-invasive, non-intrusive BP estimation can be obtained using methods that can be applied in both clinical and daily healthcare situations.
Zhou, Bang-Guo; Wang, Dan; Ren, Wei-Wei; Li, Xiao-Long; He, Ya-Ping; Liu, Bo-Ji; Wang, Qiao; Chen, Shi-Gao; Alizad, Azra; Xu, Hui-Xiong
2017-08-01
To evaluate the diagnostic performance of shear wave arrival time contour (SWATC) display for the diagnosis of breast lesions and to identify factors associated with the quality of shear wave propagation (QSWP) in breast lesions. This study included 277 pathologically confirmed breast lesions. Conventional B-mode ultrasound characteristics and shear wave elastography parameters were computed. Using the SWATC display, the QSWP of each lesion was assigned to a two-point scale: score 1 (low quality) and score 2 (high quality). Binary logistic regression analysis was performed to identify factors associated with QSWP. The area under the receiver operating characteristic curve (AUROC) for QSWP to differentiate benign from malignant lesions was 0.913, with a sensitivity of 91.9%, a specificity of 90.7%, a positive predictive value (PPV) of 74.0%, and a negative predictive value (NPV) of 97.5%. Compared with using the standard deviation of shear wave speed (SWS SD ) alone, SWS SD combined with QSWP increased the sensitivity from 75.8% to 93.5%, but decreased the specificity from 95.8% to 89.3% (P breast lesions.
Energy Technology Data Exchange (ETDEWEB)
Choi, Young Chul; Park, Tae Jin [KAERI, Daejeon (Korea, Republic of)
2016-05-15
Source localization in a dispersive medium has been carried out based on the time-of-arrival-differences (TOADs) method: a triangulation method and a circle intersection technique. Recent signal processing advances have led to calculation TOAD using a joint time-frequency analysis of the signal, where a short-time Fourier transform(STFT) and wavelet transform can be included as popular algorithms. The time-frequency analysis method is able to provide various information and more reliable results such as seismic-attenuation estimation, dispersive characteristics, a wave mode analysis, and temporal energy distribution of signals compared with previous methods. These algorithms, however, have their own limitations for signal processing. In this paper, the effective use of proposed algorithm in detecting crack wave arrival time and source localization in rock masses suggest that the evaluation and real-time monitoring on the intensity of damages related to the tunnels or other underground facilities is possible. Calculation of variances resulted from moving windows as a function of their size differentiates the signature from noise and from crack signal, which lead us to determine the crack wave arrival time. Then, the source localization is determined to be where the variance of crack wave velocities from real and virtual crack localization becomes a minimum. To validate our algorithm, we have performed experiments at the tunnel, which resulted in successful determination of the wave arrival time and crack localization.
Design and Performance Evaluation on Ultra-Wideband Time-Of-Arrival 3D Tracking System
Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Dusl, John
2012-01-01
A three-dimensional (3D) Ultra-Wideband (UWB) Time--of-Arrival (TOA) tracking system has been studied at NASA Johnson Space Center (JSC) to provide the tracking capability inside the International Space Station (ISS) modules for various applications. One of applications is to locate and report the location where crew experienced possible high level of carbon-dioxide and felt upset. In order to accurately locate those places in a multipath intensive environment like ISS modules, it requires a robust real-time location system (RTLS) which can provide the required accuracy and update rate. A 3D UWB TOA tracking system with two-way ranging has been proposed and studied. The designed system will be tested in the Wireless Habitat Testbed which simulates the ISS module environment. In this presentation, we discuss the 3D TOA tracking algorithm and the performance evaluation based on different tracking baseline configurations. The simulation results show that two configurations of the tracking baseline are feasible. With 100 picoseconds standard deviation (STD) of TOA estimates, the average tracking error 0.2392 feet (about 7 centimeters) can be achieved for configuration Twisted Rectangle while the average tracking error 0.9183 feet (about 28 centimeters) can be achieved for configuration Slightly-Twisted Top Rectangle . The tracking accuracy can be further improved with the improvement of the STD of TOA estimates. With 10 picoseconds STD of TOA estimates, the average tracking error 0.0239 feet (less than 1 centimeter) can be achieved for configuration "Twisted Rectangle".
Time of Arrival Estimation in Probability-Controlled Generalized CDMA Systems
Directory of Open Access Journals (Sweden)
Hagit Messer
2007-11-01
Full Text Available In recent years, more and more wireless communications systems are required to provide also a positioning measurement. In code division multiple access (CDMA communication systems, the positioning accuracy is significantly degraded by the multiple access interference (MAI caused by other users in the system. This MAI is commonly managed by a power control mechanism, and yet, MAI has a major effect on positioning accuracy. Probability control is a recently introduced interference management mechanism. In this mechanism, a user with excess power chooses not to transmit some of its symbols. The information in the nontransmitted symbols is recovered by an error-correcting code (ECC, while all other users receive a more reliable data during these quiet periods. Previous research had shown that the implementation of a probability control mechanism can significantly reduce the MAI. In this paper, we show that probability control also improves the positioning accuracy. We focus on time-of-arrival (TOA based positioning systems. We analyze the TOA estimation performance in a generalized CDMA system, in which the probability control mechanism is employed, where the transmitted signal is noncontinuous with a symbol transmission probability smaller than 1. The accuracy of the TOA estimation is determined using appropriate modifications of the Cramer-Rao bound on the delay estimation. Keeping the average transmission power constant, we show that the TOA accuracy of each user does not depend on its transmission probability, while being a nondecreasing function of the transmission probability of any other user. Therefore, a generalized, noncontinuous CDMA system with a probability control mechanism can always achieve better positioning performance, for all users in the network, than a conventional, continuous, CDMA system.
Arterial spin labelling reveals prolonged arterial arrival time in idiopathic Parkinson's disease.
Al-Bachari, Sarah; Parkes, Laura M; Vidyasagar, Rishma; Hanby, Martha F; Tharaken, Vivek; Leroi, Iracema; Emsley, Hedley C A
2014-01-01
Idiopathic Parkinson's disease (IPD) is the second most common neurodegenerative disease, yet effective disease modifying treatments are still lacking. Neurodegeneration involves multiple interacting pathological pathways. The extent to which neurovascular mechanisms are involved is not well defined in IPD. We aimed to determine whether novel magnetic resonance imaging (MRI) techniques, including arterial spin labelling (ASL) quantification of cerebral perfusion, can reveal altered neurovascular status (NVS) in IPD. Fourteen participants with IPD (mean ± SD age 65.1 ± 5.9 years) and 14 age and cardiovascular risk factor matched control participants (mean ± SD age 64.6 ± 4.2 years) underwent a 3T MRI scan protocol. ASL images were collected before, during and after a 6 minute hypercapnic challenge. FLAIR images were used to determine white matter lesion score. Quantitative images of cerebral blood flow (CBF) and arterial arrival time (AAT) were calculated from the ASL data both at rest and during hypercapnia. Cerebrovascular reactivity (CVR) images were calculated, depicting the change in CBF and AAT relative to the change in end-tidal CO2. A significant (p = 0.005) increase in whole brain averaged baseline AAT was observed in IPD participants (mean ± SD age 1532 ± 138 ms) compared to controls (mean ± SD age 1335 ± 165 ms). Voxel-wise analysis revealed this to be widespread across the brain. However, there were no statistically significant differences in white matter lesion score, CBF, or CVR between patients and controls. Regional CBF, but not AAT, in the IPD group was found to correlate positively with Montreal cognitive assessment (MoCA) scores. These findings provide further evidence of alterations in NVS in IPD.
International Nuclear Information System (INIS)
Brancus, I.; Duma, M.; Badea, A. F.; Aiftimiei, C.; Rebel, M. H.; Oehlschlaeger, J.
2001-01-01
By extensive Monte Carlo calculations, using the air shower simulation code CORSIKA, EAS muon arrival time distributions and EAS time profiles up to 320 m distances from the shower centre have been generated, for proton, oxygen and iron induced showers using different hadronic interaction models as Monte Carlo generators. The model dependence and mass discriminating features have been scrutinized for three energy ranges, (1-1.7783) 10 15 eV, (1.-1.78) 10 16 eV and (1.78-3.16) 10 16 eV, by use of non-parametric statistical inference method applied to multidimensional distributions, correlating the EAS time quantities with different other EAS observables. The correlations of local muon arrival times with the local muon density and the shower age indicate a good mass separation quality at larger shower distances. The best discrimination was obtained by adding the correlation with N μ tr quantity. The comparison between 'local times', with reference to the first registered muon and 'global times' with reference to the arrival time of the shower core, indicates a slightly better mass discrimination in the case of muon 'global' time distributions. (authors)
Plank, Jennifer L; Mundell, Nathan A; Frist, Audrey Y; LeGrone, Alison W; Kim, Thomas; Musser, Melissa A; Walter, Teagan J; Labosky, Patricia A
2011-01-15
Interactions between cells from the ectoderm and mesoderm influence development of the endodermally-derived pancreas. While much is known about how mesoderm regulates pancreatic development, relatively little is understood about how and when the ectodermally-derived neural crest regulates pancreatic development and specifically, beta cell maturation. A previous study demonstrated that signals from the neural crest regulate beta cell proliferation and ultimately, beta cell mass. Here, we expand on that work to describe timing of neural crest arrival at the developing pancreatic bud and extend our knowledge of the non-cell autonomous role for neural crest derivatives in the process of beta cell maturation. We demonstrated that murine neural crest entered the pancreatic mesenchyme between the 26 and 27 somite stages (approximately 10.0 dpc) and became intermingled with pancreatic progenitors as the epithelium branched into the surrounding mesenchyme. Using a neural crest-specific deletion of the Forkhead transcription factor Foxd3, we ablated neural crest cells that migrate to the pancreatic primordium. Consistent with previous data, in the absence of Foxd3, and therefore the absence of neural crest cells, proliferation of insulin-expressing cells and insulin-positive area are increased. Analysis of endocrine cell gene expression in the absence of neural crest demonstrated that, although the number of insulin-expressing cells was increased, beta cell maturation was significantly impaired. Decreased MafA and Pdx1 expression illustrated the defect in beta cell maturation; we discovered that without neural crest, there was a reduction in the percentage of insulin-positive cells that co-expressed Glut2 and Pdx1 compared to controls. In addition, transmission electron microscopy analyses revealed decreased numbers of characteristic insulin granules and the presence of abnormal granules in insulin-expressing cells from mutant embryos. Together, these data demonstrate that
P-wave and surface wave survey for permafrost analysis in alpine regions
Godio, A.; Socco, L. V.; Garofalo, F.; Arato, A.; Théodule, A.
2012-04-01
of seismic data involved the tomographic interpretation of traveltime P-wave first arrivals by considering the continuous refraction of the ray-paths. Several surface-wave dispersion curves were extracted in f-k domain along the seismic line and then inverted through a laterally constrained inversion algorithm to obtain a pseudo-2D section of S-wave velocity. Georadar investigation (about 2 km of georadar lines in the first site) confirmed the presence both of fine and coarse sediments in the uppermost layer; the seismic data allowed the moraines to be characterized down to 20-25 meters of depth. At the elevation of 2700 m asl, we observed a general decrease of the P-wave traveltimes collected in November, when the near surface layer was in frozen condition, respect to the data acquired in June. The frozen layer is responsible of the inversion of P-wave velocity with depth; the higher velocity layer (frozen) cannot be detected in the tomographic interpretation of refraction tomographic of the P-wave arrivals. Compressional wave velocity ranges from 700 m/s on the uppermost part, to 2000-2500 m/s in the internal part of the sediments reaching values higher than 5000 m/s at depth about 20 m. The analysis of surface wave permitted to estimate a slight increase from summer to winter of the S-wave velocity, in the depth range between 0 to 5 m.
Directory of Open Access Journals (Sweden)
Yogesh Tiwari
2014-01-01
Full Text Available Background: Emergency Department (ED of tertiary health care institute in India is mostly overcrowded, over utilized and inappropriately staffed. The challenges of overcrowded EDs and ill-managed patient flow and admission processes result in excessively long waits for patients. Aim: The objective of the present study was to analyze the patient flow system by assessing the arrival and waiting time distribution of patients in an Emergency out Patient Department (EOPD. Materials and Methods: This short cross-sectional descriptive study was conducted in the EOPD of a Tertiary level health care Institution in North India in the month of May, 2011. The data was obtained from 591 patients, who were present in the EOPD during the month of May, 2011. The waiting time, inter arrival time between two consecutive patients were calculated in addition to the daily census data (discharge rate, admission rate and transfer out rates etc. of the emergency. Results: Arrival time pattern of patients in the EOPD was highly stochastic with the peak arrival hours to be "9.00-12.00 h" in which around 26.3% patients arrived in the EOPD. The primary waiting areas of patients included patients "under observation" (29.6%; "waiting for routine diagnostic tests" (16.4% and "waiting for discharge" (14.6%. Around 71% patients were waiting due to reasons within emergency complex. Conclusion: The patient flow of the ED could only be addressed by multifaceted, multidisciplinary and hospital wide approach.
Wold, A. M.; Mays, M. L.; Taktakishvili, A.; Odstrcil, D.; MacNeice, P. J.; Jian, L. K.
2017-12-01
The Wang-Sheeley-Arge (WSA)-ENLIL+Cone model is used extensively in space weather operations world-wide to model CME propagation. As such, it is important to assess its performance. We present validation results of the WSA-ENLIL+Cone model installed at the Community Coordinated Modeling Center (CCMC) and executed in real-time by the CCMC/Space Weather Research Center (SWRC). CCMC/SWRC uses the WSA-ENLIL+Cone model to predict CME arrivals at NASA missions throughout the inner heliosphere. In this work we compare model predicted CME arrival-times to in-situ ICME leading edge measurements near Earth, STEREO-A and STEREO-B for simulations completed between March 2010-December 2016 (over 1,800 CMEs). We report hit, miss, false alarm, and correct rejection statistics for all three spacecraft. For all predicted CME arrivals, the hit rate is 0.5, and the false alarm rate is 0.1. For the 273 events where the CME was predicted to arrive at Earth, STEREO-A, or STEREO-B and we observed an arrival (hit), the mean absolute arrival-time prediction error was 10.4 ± 0.9 hours, with a tendency to early prediction error of -4.0 hours. We show the dependence of the arrival-time error on CME input parameters. We also explore the impact of the multi-spacecraft observations used to initialize the model CME inputs by comparing model verification results before and after the STEREO-B communication loss (since September 2014) and STEREO-A side-lobe operations (August 2014-December 2015). There is an increase of 1.7 hours in the CME arrival time error during single, or limited two-viewpoint periods, compared to the three-spacecraft viewpoint period. This trend would apply to a future space weather mission at L5 or L4 as another coronagraph viewpoint to reduce CME arrival time errors compared to a single L1 viewpoint.
International Nuclear Information System (INIS)
Hafemann, W.; Haeusler, R.; Rebel, H.; Mathes, H.J.
2000-01-01
The central detector of the KASCADE experiment is equipped with two layers of scintillation detectors with different area coverage. The scintillators of both detector systems have a good timing resolution of about 1.6 ns. With these two arrangements we performed extensive measurements of the arrival time differences at different energy thresholds of the electron and the muon component of EAS. The observed time structure of the shower profile is classified according to different EAS parameters. We furthermore present an analysis and comparism based on detailed MC simulations of the shower development. This comparism shows good agreement between experimental data and the expected behaviour of the different time distributions. (orig.)
Li, Xi-Bing; Wang, Ze-Wei; Dong, Long-Jun
2016-01-01
Microseismic monitoring systems using local location techniques tend to be timely, automatic and stable. One basic requirement of these systems is the automatic picking of arrival times. However, arrival times generated by automated techniques always contain large picking errors (LPEs), which may make the location solution unreliable and cause the integrated system to be unstable. To overcome the LPE issue, we propose the virtual field optimization method (VFOM) for locating single-point sources. In contrast to existing approaches, the VFOM optimizes a continuous and virtually established objective function to search the space for the common intersection of the hyperboloids, which is determined by sensor pairs other than the least residual between the model-calculated and measured arrivals. The results of numerical examples and in-site blasts show that the VFOM can obtain more precise and stable solutions than traditional methods when the input data contain LPEs. Furthermore, we discuss the impact of LPEs on objective functions to determine the LPE-tolerant mechanism, velocity sensitivity and stopping criteria of the VFOM. The proposed method is also capable of locating acoustic sources using passive techniques such as passive sonar detection and acoustic emission.
Zhu, Junxiao; Parvasi, Seyed Mohammad; Ho, Siu Chun Michael; Patil, Devendra; Ge, Maochen; Li, Hongnan; Song, Gangbing
2017-05-01
Lamb waves have great potential as a diagnostic tool in the application of structural health monitoring. Propagation properties of Lamb waves are affected by the state of the structure that the waves are traveling upon. Thus Lamb waves can carry information about the structure as they travel across a structure. However, the dispersive, multimodal and attenuation characteristics of Lamb waves make it difficult to determine the time of arrival of Lamb waves. To deal with these characteristics, an innovative method to automatically determine the time of arrival for impact-induced Lamb waves without human intervention is proposed in this paper. Lead zirconate titanate sensors mounted on the surface of an aluminum plate were used to measure the Lamb waves excited by an impact. The time of arrival was determined based on wavelet decomposition, Hilbert transform and statistics (Grubbs’ test and maximum likelihood estimation). Both of numerical analysis and physical measurements have verified the accuracy of this method for impacts on an aluminum plate.
Martínez, Arturo; Alcaraz, Raul; Rieta, Jose J
2014-01-01
The present work introduces the first study on the P-wave morphological variability two hours preceding the onset of paroxysmal atrial fibrillation (PAF). The development of non-invasive methods able to track P-wave alterations over time is a clinically relevant tool to anticipate as much as possible the envision of a new PAF episode. This information is essential for further improvement of preventive and patient-tailored treatment strategies, which could avert the loss of sinus rhythm. In this way, risks for the patients could be minimized and their quality of life improved. Recently, the P-wave morphological analysis is drawing increasing attention because differences in morphology can reflect different atrial activation patterns. Indeed, the P-wave morphology study has recently proved to be useful for determining the presence of an underlying pathophysiological condition in patients prone to atrial fibrillation. However, the P-wave morphology variability over time has not been studied yet. In this respect, the present work puts forward some parameters related to the P-wave shape and energy with the ability to quantify non-invasively the notable atrial conduction alterations preceding the onset of PAF. Results showed that P-wave fragmentation and area presented higher variability over time as the onset of PAF approximates. By properly combining these indices, an average global accuracy of 86.33% was achieved to discern between electrocardiogram segments from healthy subjects, far from a PAF episode and less than one hour close to a PAF episode. As a consequence, the P-wave morphology long-term analysis seems to be a useful tool for the non-invasive envision of PAF onset with a reasonable anticipation. Nonetheless, further research is required to corroborate this finding and to validate the capability of the proposed P-wave metrics in the earlier prediction of PAF onset.
International Nuclear Information System (INIS)
Martínez, Arturo; Alcaraz, Raul; Rieta, Jose J
2014-01-01
The present work introduces the first study on the P-wave morphological variability two hours preceding the onset of paroxysmal atrial fibrillation (PAF). The development of non-invasive methods able to track P-wave alterations over time is a clinically relevant tool to anticipate as much as possible the envision of a new PAF episode. This information is essential for further improvement of preventive and patient-tailored treatment strategies, which could avert the loss of sinus rhythm. In this way, risks for the patients could be minimized and their quality of life improved. Recently, the P-wave morphological analysis is drawing increasing attention because differences in morphology can reflect different atrial activation patterns. Indeed, the P-wave morphology study has recently proved to be useful for determining the presence of an underlying pathophysiological condition in patients prone to atrial fibrillation. However, the P-wave morphology variability over time has not been studied yet. In this respect, the present work puts forward some parameters related to the P-wave shape and energy with the ability to quantify non-invasively the notable atrial conduction alterations preceding the onset of PAF. Results showed that P-wave fragmentation and area presented higher variability over time as the onset of PAF approximates. By properly combining these indices, an average global accuracy of 86.33% was achieved to discern between electrocardiogram segments from healthy subjects, far from a PAF episode and less than one hour close to a PAF episode. As a consequence, the P-wave morphology long-term analysis seems to be a useful tool for the non-invasive envision of PAF onset with a reasonable anticipation. Nonetheless, further research is required to corroborate this finding and to validate the capability of the proposed P-wave metrics in the earlier prediction of PAF onset. (paper)
Holographic p-wave superconductor with disorder
International Nuclear Information System (INIS)
Areán, D.; Farahi, A.; Zayas, L.A. Pando; Landea, I. Salazar; Scardicchio, A.
2015-01-01
We implement the effects of disorder on a holographic p-wave superconductor by introducing a random chemical potential which defines the local energy of the charge carriers. Since there are various possibilities for the orientation of the vector order parameter, we explore the behavior of the condensate in the parallel and perpendicular directions to the introduced disorder. We clarify the nature of various branches representing competing solutions and construct the disordered phase diagram. We find that moderate disorder enhances superconductivity as determined by the value of the condensate. Though we mostly focus on uncorrelated noise, we also consider a disorder characterized by its spectral properties and study in detail its influence on the spectral properties of the condensate and charge density. We find fairly universal responses of the resulting power spectra characterized by linear functions of the disorder power spectrum.
Application of perturbation theory to a P-wave eikonal equation in orthorhombic media
Stovas, Alexey; Masmoudi, Nabil; Alkhalifah, Tariq Ali
2016-01-01
The P-wave eikonal equation for orthorhombic (ORT) anisotropic media is a highly nonlinear partial differential equation requiring the solution of a sixth-order polynomial to obtain traveltimes, resulting in complex and time-consuming numerical
Energy Technology Data Exchange (ETDEWEB)
Arzoumanian, Zaven [Center for Research and Exploration in Space Science and Technology and X-Ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Brazier, Adam; Chatterjee, Shami; Cordes, James M.; Dolch, Timothy [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Burke-Spolaor, Sarah; Demorest, Paul B. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Chamberlin, Sydney [Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States); Christy, Brian [Department of Physics and Astronomy, Franklin and Marshall College, P.O. Box 3003, Lancaster, PA 17604 (United States); Cornish, Neil [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Crowter, Kathryn; Fonseca, Emmanuel; Gonzalez, Marjorie E. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Ellis, Justin A. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr. Pasadena CA 91109 (United States); Ferdman, Robert D.; Kaspi, Victoria M. [Department of Physics, McGill University, 3600 rue Universite, Montreal, QC H3A 2T8 (Canada); Garver-Daniels, Nathan; Jones, Megan L. [Department of Physics, West Virginia University, P.O. Box 6315, Morgantown, WV 26505 (United States); Jenet, Fredrick A. [Center for Gravitational Wave Astronomy, University of Texas at Brownsville, Brownsville, TX 78520 (United States); Jones, Glenn, E-mail: pdemores@nrao.edu [Department of Physics, Columbia University, 550 W. 120th St. New York, NY 10027 (United States); Collaboration: NANOGrav Collaboration; and others
2015-11-01
We present high-precision timing observations spanning up to nine years for 37 millisecond pulsars monitored with the Green Bank and Arecibo radio telescopes as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project. We describe the observational and instrumental setups used to collect the data, and methodology applied for calculating pulse times of arrival; these include novel methods for measuring instrumental offsets and characterizing low signal-to-noise ratio timing results. The time of arrival data are fit to a physical timing model for each source, including terms that characterize time-variable dispersion measure and frequency-dependent pulse shape evolution. In conjunction with the timing model fit, we have performed a Bayesian analysis of a parameterized timing noise model for each source, and detect evidence for excess low-frequency, or “red,” timing noise in 10 of the pulsars. For 5 of these cases this is likely due to interstellar medium propagation effects rather than intrisic spin variations. Subsequent papers in this series will present further analysis of this data set aimed at detecting or limiting the presence of nanohertz-frequency gravitational wave signals.
Liu, Huawei; Li, Baoqing; Yuan, Xiaobing; Zhou, Qianwei; Huang, Jingchang
2018-03-27
Parameters estimation of sequential movement events of vehicles is facing the challenges of noise interferences and the demands of portable implementation. In this paper, we propose a robust direction-of-arrival (DOA) estimation method for the sequential movement events of vehicles based on a small Micro-Electro-Mechanical System (MEMS) microphone array system. Inspired by the incoherent signal-subspace method (ISM), the method that is proposed in this work employs multiple sub-bands, which are selected from the wideband signals with high magnitude-squared coherence to track moving vehicles in the presence of wind noise. The field test results demonstrate that the proposed method has a better performance in emulating the DOA of a moving vehicle even in the case of severe wind interference than the narrowband multiple signal classification (MUSIC) method, the sub-band DOA estimation method, and the classical two-sided correlation transformation (TCT) method.
Directory of Open Access Journals (Sweden)
Elibet Chávez
2011-07-01
Full Text Available Introducción: hace algunos años se viene estudiando la relación entre disfunción diastólica y dispersión de la onda P del electrocardiograma, y en este sentido, la ecocardiografía emerge como herramienta para mejorar la estratificación de riesgo en hipertensos leves. Objetivo: determinar la dependencia de la dispersión de la onda P del electrocardiograma de variables ecocardiográficas en una población pediátrica. Métodos: se estudiaron 400 niños, de un total de 450, pertenecientes a tres escuelas primarias, y se excluyeron aquellos cuyos padres no desearon que participaran en el estudio y a quienes tuvieran patologías congénitas conocidas. Se realizó electrocardiograma de superficie de doce derivaciones y se practicaron cuatro tomas de presión arterial. Se midieron los valores de P máxima y P mínima, y se calculó la dispersión de la onda P del electrocardiograma; además se hizo, ecocardiografía para mediciones estructurales y Doppler pulsado del flujo mitral. Resultados: los valores de media para la duración de la onda A del flujo mitral no muestran diferencias significativas; sin embargo, existe un coeficiente de correlación (r y p significativos entre la dispersión de la onda P y la duración de la onda A del flujo mitral para normotensos (r= - 0,117 p=0,05, prehipertensos (r= - 0,309 p=0,001 e hipertensos (r= - 0,586 p=0,001. Existen diferencias significativas entre las medias de dispersión de la onda P entre los grupos de diagnóstico. Conclusiones: se evidencia dependencia de la dispersión de la onda P, del electrocardiograma y de la duración de la onda A del flujo de entrada mitral, hechos que se relacionan con riesgo de fibrilación auricular en el adulto, por lo que quizás este resultado dé un acercamiento a predicciones de riesgo más tempranas en edades pediátricas.Introduction: the relationship between diastolic dysfunction and P wave dispersion in the electrocardiogram is being studied since some
Wold, Alexandra M.; Mays, M. Leila; Taktakishvili, Aleksandre; Jian, Lan K.; Odstrcil, Dusan; MacNeice, Peter
2018-03-01
The Wang-Sheeley-Arge (WSA)-ENLIL+Cone model is used extensively in space weather operations world-wide to model coronal mass ejection (CME) propagation. As such, it is important to assess its performance. We present validation results of the WSA-ENLIL+Cone model installed at the Community Coordinated Modeling Center (CCMC) and executed in real-time by the CCMC space weather team. CCMC uses the WSA-ENLIL+Cone model to predict CME arrivals at NASA missions throughout the inner heliosphere. In this work we compare model predicted CME arrival-times to in situ interplanetary coronal mass ejection leading edge measurements at Solar TErrestrial RElations Observatory-Ahead (STEREO-A), Solar TErrestrial RElations Observatory-Behind (STEREO-B), and Earth (Wind and ACE) for simulations completed between March 2010 and December 2016 (over 1,800 CMEs). We report hit, miss, false alarm, and correct rejection statistics for all three locations. For all predicted CME arrivals, the hit rate is 0.5, and the false alarm rate is 0.1. For the 273 events where the CME was predicted to arrive at Earth, STEREO-A, or STEREO-B, and was actually observed (hit event), the mean absolute arrival-time prediction error was 10.4 ± 0.9 h, with a tendency to early prediction error of -4.0 h. We show the dependence of the arrival-time error on CME input parameters. We also explore the impact of the multi-spacecraft observations used to initialize the model CME inputs by comparing model verification results before and after the STEREO-B communication loss (since September 2014) and STEREO-A sidelobe operations (August 2014-December 2015). There is an increase of 1.7 h in the CME arrival time error during single, or limited two-viewpoint periods, compared to the three-spacecraft viewpoint period. This trend would apply to a future space weather mission at L5 or L4 as another coronagraph viewpoint to reduce CME arrival time errors compared to a single L1 viewpoint.
International Nuclear Information System (INIS)
Supardiyono; Santosa, Bagus Jaya
2012-01-01
A one-dimensional (1-D) velocity model and station corrections for the West Java zone were computed by inverting P-wave arrival times recorded on a local seismic network of 14 stations. A total of 61 local events with a minimum of 6 P-phases, rms 0.56 s and a maximum gap of 299° were selected. Comparison with previous earthquake locations shows an improvement for the relocated earthquakes. Tests were carried out to verify the robustness of inversion results in order to corroborate the conclusions drawn out from our reasearch. The obtained minimum 1-D velocity model can be used to improve routine earthquake locations and represents a further step toward more detailed seismotectonic studies in this area of West Java.
Energy Technology Data Exchange (ETDEWEB)
Supardiyono; Santosa, Bagus Jaya [Physics Department, Faculty of Mathematics and Natural Sciences, State University of Surabaya, Surabaya (Indonesia) and Physics Department, Faculty of Mathematics and Natural Sciences, Sepuluh Nopember Institute of Technology, Surabaya (Indonesia); Physics Department, Faculty of Mathematics and Natural Sciences, Sepuluh Nopember Institute of Technology, Surabaya (Indonesia)
2012-06-20
A one-dimensional (1-D) velocity model and station corrections for the West Java zone were computed by inverting P-wave arrival times recorded on a local seismic network of 14 stations. A total of 61 local events with a minimum of 6 P-phases, rms 0.56 s and a maximum gap of 299 Degree-Sign were selected. Comparison with previous earthquake locations shows an improvement for the relocated earthquakes. Tests were carried out to verify the robustness of inversion results in order to corroborate the conclusions drawn out from our reasearch. The obtained minimum 1-D velocity model can be used to improve routine earthquake locations and represents a further step toward more detailed seismotectonic studies in this area of West Java.
Depth of source from long period P-waves
International Nuclear Information System (INIS)
Roy, Falguni
1986-01-01
Short period (SP) seismograms are much better than long period (LP) seismograms to get the time resolution needed for the focal depth estimation. However, complex scattering effects due to crustal inhomogeneities and also the multi-pathing of signals usually complicate the short period records. On the other hand the seismograms from long period signals demonstrate clear coherent body waves. Therefore, for intermediate depths (15-60 km) prediction error filtering of LP signals will be useful for identifying the depth phases. Such a study has been carried out in the first part of this report. In a group of 7 events, the p p phases have been extracted from LP signals and the depths so estimated compared well with the published data. For explosions at shallow depths (depth p phases will tend to cancel each other in LP seismograms. As the source depth increases, the cancellation becomes less effective. This feature can be used for the identification of an event as well as for getting an estimate of the source depth. This phenomenon can be successfully exploited for identifying multiple explosions, because at teleseismic distances (Δ > 30 o ) no LP (around 20s period) P waves will be seen in the seismogram due to such events whereas relatively strong SP signals and LP Rayleigh waves will be observed. This phenomenon has been studied for 16 events. For three of these events having m b as high as 6.1 and presumed to be underground explosions, one could not see any P wave on remaining 13 events (which were classified as earthquakes), it was possible to set a threshold value of m b above which an earthquake should produce LP P-wave signals at a given distance. (author)
Connecting speeds, directions and arrival times of 22 coronal mass ejections from the sun to 1 AU
Energy Technology Data Exchange (ETDEWEB)
Möstl, C.; Veronig, A. M.; Rollett, T.; Temmer, M.; Peinhart, V. [Kanzelhöhe Observatory-IGAM, Institute of Physics, University of Graz (Austria); Amla, K.; Hall, J. R.; Liewer, P. C.; De Jong, E. M. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA (United States); Colaninno, R. C. [Space Sciences Division, Naval Research Laboratory, Washington, DC (United States); Davies, J. A.; Harrison, R. A. [RAL Space, Harwell Oxford, Didcot (United Kingdom); Lugaz, N.; Farrugia, C. J.; Galvin, A. B. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH (United States); Liu, Y. D. [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China); Luhmann, J. G. [Space Science Laboratory, University of California, Berkeley, CA (United States); Vršnak, B., E-mail: christian.moestl@uni-graz.at [Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kačićeva 26, HR-10000, Zagreb (Croatia)
2014-06-01
Forecasting the in situ properties of coronal mass ejections (CMEs) from remote images is expected to strongly enhance predictions of space weather and is of general interest for studying the interaction of CMEs with planetary environments. We study the feasibility of using a single heliospheric imager (HI) instrument, imaging the solar wind density from the Sun to 1 AU, for connecting remote images to in situ observations of CMEs. We compare the predictions of speed and arrival time for 22 CMEs (in 2008-2012) to the corresponding interplanetary coronal mass ejection (ICME) parameters at in situ observatories (STEREO PLASTIC/IMPACT, Wind SWE/MFI). The list consists of front- and backsided, slow and fast CMEs (up to 2700 km s{sup –1}). We track the CMEs to 34.9 ± 7.1 deg elongation from the Sun with J maps constructed using the SATPLOT tool, resulting in prediction lead times of –26.4 ± 15.3 hr. The geometrical models we use assume different CME front shapes (fixed-Φ, harmonic mean, self-similar expansion) and constant CME speed and direction. We find no significant superiority in the predictive capability of any of the three methods. The absolute difference between predicted and observed ICME arrival times is 8.1 ± 6.3 hr (rms value of 10.9 hr). Speeds are consistent to within 284 ± 288 km s{sup –1}. Empirical corrections to the predictions enhance their performance for the arrival times to 6.1 ± 5.0 hr (rms value of 7.9 hr), and for the speeds to 53 ± 50 km s{sup –1}. These results are important for Solar Orbiter and a space weather mission positioned away from the Sun-Earth line.
Lisovski, Simeon; Fröhlich, Anne; von Tersch, Matthew; Klaassen, Marcel; Peter, Hans-Ulrich; Ritz, Markus S
2016-04-01
In migratory animals, protandry (earlier arrival of males on the breeding grounds) prevails over protogyny (females preceding males). In theory, sex differences in timing of arrival should be driven by the operational sex ratio, shifting toward protogyny in female-biased populations. However, empirical support for this hypothesis is, to date, lacking. To test this hypothesis, we analyzed arrival data from three populations of the long-distance migratory south polar skua (Catharacta maccormicki). These populations differed in their operational sex ratio caused by the unidirectional hybridization of male south polar skuas with female brown skuas (Catharacta antarctica lonnbergi). We found that arrival times were protandrous in allopatry, shifting toward protogyny in female-biased populations when breeding in sympatry. This unique observation is consistent with theoretical predictions that sex-specific arrival times should be influenced by sex ratio and that protogyny should be observed in populations with female-biased operational sex ratio.
Triplicated P-wave measurements for waveform tomography of the mantle transition zone
Directory of Open Access Journals (Sweden)
S. C. Stähler
2012-11-01
Full Text Available Triplicated body waves sample the mantle transition zone more extensively than any other wave type, and interact strongly with the discontinuities at 410 km and 660 km. Since the seismograms bear a strong imprint of these geodynamically interesting features, it is highly desirable to invert them for structure of the transition zone. This has rarely been attempted, due to a mismatch between the complex and band-limited data and the (ray-theoretical modelling methods. Here we present a data processing and modelling strategy to harness such broadband seismograms for finite-frequency tomography. We include triplicated P-waves (epicentral distance range between 14 and 30° across their entire broadband frequency range, for both deep and shallow sources. We show that is it possible to predict the complex sequence of arrivals in these seismograms, but only after a careful effort to estimate source time functions and other source parameters from data, variables that strongly influence the waveforms. Modelled and observed waveforms then yield decent cross-correlation fits, from which we measure finite-frequency traveltime anomalies. We discuss two such data sets, for North America and Europe, and conclude that their signal quality and azimuthal coverage should be adequate for tomographic inversion. In order to compute sensitivity kernels at the pertinent high body wave frequencies, we use fully numerical forward modelling of the seismic wavefield through a spherically symmetric Earth.
Chong, Ka Chun; Zee, Benny Chung Ying; Wang, Maggie Haitian
2018-04-10
In an influenza pandemic, arrival times of cases are a proxy of the epidemic size and disease transmissibility. Because of intense surveillance of travelers from infected countries, detection is more rapid and complete than on local surveillance. Travel information can provide a more reliable estimation of transmission parameters. We developed an Approximate Bayesian Computation algorithm to estimate the basic reproduction number (R 0 ) in addition to the reporting rate and unobserved epidemic start time, utilizing travel, and routine surveillance data in an influenza pandemic. A simulation was conducted to assess the sampling uncertainty. The estimation approach was further applied to the 2009 influenza A/H1N1 pandemic in Mexico as a case study. In the simulations, we showed that the estimation approach was valid and reliable in different simulation settings. We also found estimates of R 0 and the reporting rate to be 1.37 (95% Credible Interval [CI]: 1.26-1.42) and 4.9% (95% CI: 0.1%-18%), respectively, in the 2009 influenza pandemic in Mexico, which were robust to variations in the fixed parameters. The estimated R 0 was consistent with that in the literature. This method is useful for officials to obtain reliable estimates of disease transmissibility for strategic planning. We suggest that improvements to the flow of reporting for confirmed cases among patients arriving at different countries are required. Copyright © 2018 Elsevier Ltd. All rights reserved.
IEEE 802.15.4 ZigBee-Based Time-of-Arrival Estimation for Wireless Sensor Networks.
Cheon, Jeonghyeon; Hwang, Hyunsu; Kim, Dongsun; Jung, Yunho
2016-02-05
Precise time-of-arrival (TOA) estimation is one of the most important techniques in RF-based positioning systems that use wireless sensor networks (WSNs). Because the accuracy of TOA estimation is proportional to the RF signal bandwidth, using broad bandwidth is the most fundamental approach for achieving higher accuracy. Hence, ultra-wide-band (UWB) systems with a bandwidth of 500 MHz are commonly used. However, wireless systems with broad bandwidth suffer from the disadvantages of high complexity and high power consumption. Therefore, it is difficult to employ such systems in various WSN applications. In this paper, we present a precise time-of-arrival (TOA) estimation algorithm using an IEEE 802.15.4 ZigBee system with a narrow bandwidth of 2 MHz. In order to overcome the lack of bandwidth, the proposed algorithm estimates the fractional TOA within the sampling interval. Simulation results show that the proposed TOA estimation algorithm provides an accuracy of 0.5 m at a signal-to-noise ratio (SNR) of 8 dB and achieves an SNR gain of 5 dB as compared with the existing algorithm. In addition, experimental results indicate that the proposed algorithm provides accurate TOA estimation in a real indoor environment.
Energy Technology Data Exchange (ETDEWEB)
Penirschke, Andreas; Angelovski, Aleksandar; Jakoby, Rolf [TU Darmstadt, Institut fuer Mikrowellentechnik und Photonik, Merckstr. 25, 64283 Darmstadt (Germany); Sydlo, Cezary; Bousonville, Michael; Czwalinna, Marie Kristin; Schlarb, Holger [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kuhl, Alexander [University of Hamburg, Physics Department, Accelerator Physics Group (Germany); Weiland, Thomas [Technische Univ. Darmstadt (Germany). Inst. fuer Theorie Elektromagnetischer Felder
2013-07-01
High gain Free-Electron Lasers can generate ultra short X-ray pulses in the femtosecond range. For a stable operation of the FEL, the precise knowledge of the bunch arrival time is crucial. A novel high bandwidth Bunch Arrival time Monitor was recently installed at FLASH to allow a low charge operation mode with a sub-10 fs resolution for bunch charges of 20 pC or more. The BAM is equipped with cone shaped pickups for the precise measurement of both, the high and low bunch charge operation mode. For the extension of FLASH facility to FLASH II new pickups for the high bandwidth BAMs need to be developed. The new BAM needs to maximize the voltage level of the beam induced signal for low charge operation mode in order to provide sufficient signal strength for the subsequent electronics. In this talk, we present concepts to improve the signal strength at the electro-optic modulators for low charge operation at FLASH II and XFEL.
International Nuclear Information System (INIS)
Matsubara, Susumu; Uchida, Chiharu; Sato, Sei; Ishida, Junichi; Masuya, Ryozo; Makiguchi, Mako; Kanamori, Isao
2001-01-01
Hepatic arterial dominant phase in helical dynamic CT was optimized by measuring the arrival time of contrast media (ATCM) with time-density curve (TDC). Subjects were 1005 patients (577 males and 428 females) and 98 nodules diagnosed as advanced hepatocellular carcinoma (HCC). The CT was done with Toshiba 4MHU X-vision SP, ultrasonography with Toshiba SSH-160A and automatic infusion of the contrast medium, iopamidol or iohexol, with Nemotokyorindo Autoenhance A-50. ATCM was found correlated with pulse rate and with arterial diameter, and significantly different between the sex. Elevation slope of TDC was suggested to be made constant by a defined infusion time of the dose corrected by body weight. Fluctuation of TDC among patients , when normalized by ATCM, was found smaller and the TDC was suggested to be useful for better imaging of HCC of less than 10 mm diameter. (K.H.)
Fedorov, M. V.; Sysoeva, A. A.; Vintskevich, S. V.; Grigoriev, D. A.
2018-03-01
The well-known Hong-Ou-Mandel effect is revisited. Two physical reasons are discussed for the effect to be less pronounced or even to disappear: differing polarizations of photons coming to the beamsplitter and delay time of photons in one of two channels. For the latter we use the concepts of biphoton frequency and temporal wave functions depending, correspondingly, on two frequency continuous variables of photons and on two time variables t 1 and t 2 interpreted as the arrival times of photons to the beamsplitter. Explicit expressions are found for the probability densities and total probabilities for photon pairs to be split between two channels after the beamsplitter and to be unsplit, when two photons appear together in one of two channels.
Optimizing Time Windows For Managing Export Container Arrivals At Chinese Container Terminals
DEFF Research Database (Denmark)
Chen, Gang; Yang, Zhongzhen
2010-01-01
window management programme that is widely used in Chinese terminals to facilitate terminal and truck delivery operations. Firstly, the arrangement of time windows is assumed to follow the principle of minimizing transport costs. A cost function is defined that includes the costs of truck and driver...... waiting time, fuel consumption associated with truck idling, storage time of the containerized cargos and yard fee. Secondly, to minimize the total cost, a heuristic is developed based on a genetic algorithm to find a near optimal time window arrangement. The optimized solution involves the position...
OPTIMIZING TIME WINDOWS FOR MANAGING ARRIVALS OF EXPORT CONTAINERS AT CHINESE CONTAINER TERMINALS
DEFF Research Database (Denmark)
Chen, Gang; Yang, Zhongzhen
2009-01-01
of driver and truck waiting time, the cost of container cargo storage time, the truck idle cost and terminal yard fee. Secondly, to minimize the costs, a heuristic is developed based on a genetic algorithm to optimize the time window arrangement. The optimal solution involves the position and the length...... window management programme that is widely used in Chinese terminals to facilitate the terminal operations and the truck delivery operations. Firstly, the arrangement of time windows is assumed to follow the principle of minimizing the transport costs. A cost function is defined that includes the cost...
Earthquake early warning using P-waves that appear after initial S-waves
Kodera, Y.
2017-12-01
As measures for underprediction for large earthquakes with finite faults and overprediction for multiple simultaneous earthquakes, Hoshiba (2013), Hoshiba and Aoki (2015), and Kodera et al. (2016) proposed earthquake early warning (EEW) methods that directly predict ground motion by computing the wave propagation of observed ground motion. These methods are expected to predict ground motion with a high accuracy even for complicated scenarios because these methods do not need source parameter estimation. On the other hand, there is room for improvement in their rapidity because they predict strong motion prediction mainly based on the observation of S-waves and do not explicitly use P-wave information available before the S-waves. In this research, we propose a real-time P-wave detector to incorporate P-wave information into these wavefield-estimation approaches. P-waves within a few seconds from the P-onsets are commonly used in many existing EEW methods. In addition, we focus on P-waves that may appear in the later part of seismic waves. Kurahashi and Irikura (2013) mentioned that P-waves radiated from strong motion generation areas (SMGAs) were recognizable after S-waves of the initial rupture point in the 2011 off the Pacific coast of Tohoku earthquake (Mw 9.0) (the Tohoku-oki earthquake). Detecting these P-waves would enhance the rapidity of prediction for the peak ground motion generated by SMGAs. We constructed a real-time P-wave detector that uses a polarity analysis. Using acceleration records in boreholes of KiK-net (band-pass filtered around 0.5-10 Hz with site amplification correction), the P-wave detector performed the principal component analysis with a sliding window of 4 s and calculated P-filter values (e.g. Ross and Ben-Zion, 2014). The application to the Tohoku-oki earthquake (Mw 9.0) showed that (1) peaks of P-filter that corresponded to SMGAs appeared in several stations located near SMGAs and (2) real-time seismic intensities (Kunugi et al
Regional P-wave Tomography in the Caribbean Region for Plate Reconstruction
Li, X.; Bedle, H.; Suppe, J.
2017-12-01
The complex plate-tectonic interactions around the Caribbean Sea have been studied and interpreted by many researchers, but questions still remain regarding the formation and subduction history of the region. Here we report current progress towards creating a new regional tomographic model, with better lateral and spatial coverage and higher resolution than has been presented previously. This new model will provide improved constraints on the plate-tectonic evolution around the Caribbean Plate. Our three-dimensional velocity model is created using taut spline parameterization. The inversion is computed by the code of VanDecar (1991), which is based on the ray theory method. The seismic data used in this inversion are absolute P wave arrival times from over 700 global earthquakes that were recorded by over 400 near Caribbean stations. There are over 25000 arrival times that were picked and quality checked within frequency band of 0.01 - 0.6 Hz by using a MATLAB GUI-based software named Crazyseismic. The picked seismic delay time data are analyzed and compared with other studies ahead of doing the inversion model, in order to examine the quality of our dataset. From our initial observations of the delay time data, the more equalized the ray azimuth coverage, the smaller the deviation of the observed travel times from the theoretical travel time. Networks around the NE and SE side of the Caribbean Sea generally have better ray coverage, and smaller delay times. Specifically, seismic rays reaching SE Caribbean networks, such as XT network, generally pass through slabs under South American, Central American, Lesser Antilles, Southwest Caribbean, and the North Caribbean transform boundary, which leads to slightly positive average delay times. In contrast, the Puerto Rico network records seismic rays passing through regions that may lack slabs in the upper mantle and show slightly negative or near zero average delay times. These results agree with previous tomographic
Magnitude scaling relationship from the first P-wave arrivals on Canada's west coast
Eshaghi, A.; Tiampo, K. F.
2011-12-01
The empirical magnitude scaling relationship from ground-motion period parameter τc is derived using vertical waveforms recorded in the Cascadia Subduction Zone (CSZ) along Canada's west coast. A high-pass filtered displacement amplitude parameter, Pd, is calculated from the initial 3 s of the P waveforms and the empirical relationship between Pd and peak ground velocity, PGV, is derived using the same data set. We selected earthquakes of M >3.0 recorded during 1996-2009 by the seismic network stations in the region operated by National Resources Canada (NRCan). In total, 90 events were selected and the vertical components of the earthquakes signals were converted to ground velocity and displacement. The displacements were filtered with a one-way Butterworth high-pass filter with a cut-off frequency of 0.075 Hz. Pd and τc are computed from the vertical seismogram components. While the average magnitude error was approximately 0.70 magnitude units when using the individual record, the error dropped to approximately 0.5 magnitude units when using the average τc for each event. In case of PGV, the average error is approximately 0.3. These relationships may be used for initial steps in establishing an earthquake early warning system for the CSZ.
P-wave duration and the risk of atrial fibrillation
DEFF Research Database (Denmark)
Nielsen, Jonas B; Kühl, Jørgen T; Pietersen, Adrian
2015-01-01
BACKGROUND: Results on the association between P-wave duration and the risk of atrial fibrillation (AF) are conflicting. OBJECTIVE: The purpose of this study was to obtain a detailed description of the relationship between P-wave duration and the risk of AF. METHODS: Using computerized analysis o...
Waveform inversion for orthorhombic anisotropy with P waves: feasibility and resolution
Kazei, Vladimir; Alkhalifah, Tariq
2018-05-01
Various parametrizations have been suggested to simplify inversions of first arrivals, or P waves, in orthorhombic anisotropic media, but the number and type of retrievable parameters have not been decisively determined. We show that only six parameters can be retrieved from the dynamic linearized inversion of P waves. These parameters are different from the six parameters needed to describe the kinematics of P waves. Reflection-based radiation patterns from the P-P scattered waves are remapped into the spectral domain to allow for our resolution analysis based on the effective angle of illumination concept. Singular value decomposition of the spectral sensitivities from various azimuths, offset coverage scenarios and data bandwidths allows us to quantify the resolution of different parametrizations, taking into account the signal-to-noise ratio in a given experiment. According to our singular value analysis, when the primary goal of inversion is determining the velocity of the P waves, gradually adding anisotropy of lower orders (isotropic, vertically transversally isotropic and orthorhombic) in hierarchical parametrization is the best choice. Hierarchical parametrization reduces the trade-off between the parameters and makes gradual introduction of lower anisotropy orders straightforward. When all the anisotropic parameters affecting P-wave propagation need to be retrieved simultaneously, the classic parametrization of orthorhombic medium with elastic stiffness matrix coefficients and density is a better choice for inversion. We provide estimates of the number and set of parameters that can be retrieved from surface seismic data in different acquisition scenarios. To set up an inversion process, the singular values determine the number of parameters that can be inverted and the resolution matrices from the parametrizations can be used to ascertain the set of parameters that can be resolved.
Traffic Responsive Control of Intersections with Predicted Arrival Times: A Markovian Approach
Haijema, R.; Hendrix, E.M.T.
2014-01-01
The dynamic adaptive control of traffic lights can be formulated as a Markov decision problem (MDP). This framework is hardly used, as solving an MDP can be very time-consuming and is only possible for simple infrastructures with a small number of traffic flows. Nevertheless, we show that the MDP
An X-ray CCD signal generator with true random arrival time
International Nuclear Information System (INIS)
Huo Jia; Xu Yuming; Chen Yong; Cui Weiwei; Li Wei; Zhang Ziliang; Han Dawei; Wang Yusan; Wang Juan
2011-01-01
An FPGA-based true random signal generator with adjustable amplitude and exponential distribution of time interval is presented. Since traditional true random number generators (TRNG) are resource costly and difficult to transplant, we employed a method of random number generation based on jitter and phase noise in ring oscillators formed by gates in an FPGA. In order to improve the random characteristics, a combination of two different pseudo-random processing circuits is used for post processing. The effects of the design parameters, such as sample frequency are discussed. Statistical tests indicate that the generator can well simulate the timing behavior of random signals with Poisson distribution. The X-ray CCD signal generator will be used in debugging the CCD readout system of the Low Energy X-ray Instrument onboard the Hard X-ray Modulation Telescope (HXMT). (authors)
International Nuclear Information System (INIS)
Thompson, C.B.; McArthur, R.D.; Hutchinson, S.W.
1994-09-01
As part of the U.S. Department of Energy's Off-Site Radiation Exposure Review Project, the time of fallout arrival and the H+12 exposure rate were estimated for populated locations in Arizona, California, Nevada, and Utah that were affected by fallout from one or more nuclear tests at the Nevada Test Site. Estimates of exposure rate were derived from measured values recorded before and after each test by fallout monitors in the field. The estimate for a given location was obtained by retrieving from a data base all measurements made in the vicinity, decay-correcting them to H+12, and calculating an average. Estimates were also derived from maps produced after most events that show isopleths of exposure rate and time of fallout arrival. Both sets of isopleths on these maps were digitized, and kriging was used to interpolate values at the nodes of a 10-km grid covering the pattern. The values at any location within the grid were then estimated from the values at the surrounding grid nodes. Estimates of dispersion (standard deviation) were also calculated. The Town Data Base contains the estimates for all combinations of location and nuclear event for which the estimated mean H+12 exposure rate was greater than three times background. A listing of the data base is included as an appendix. The information was used by other project task groups to estimate the radiation dose that off-site populations and individuals may have received as a result of exposure to fallout from Nevada nuclear tests
Amini, Changeez; Taherpour, Abbas; Khattab, Tamer; Gazor, Saeed
2017-01-01
This paper presents an improved propagation channel model for the visible light in indoor environments. We employ this model to derive an enhanced positioning algorithm using on the relation between the time-of-arrivals (TOAs) and the distances for two cases either by assuming known or unknown transmitter and receiver vertical distances. We propose two estimators, namely the maximum likelihood estimator and an estimator by employing the method of moments. To have an evaluation basis for these methods, we calculate the Cramer-Rao lower bound (CRLB) for the performance of the estimations. We show that the proposed model and estimations result in a superior performance in positioning when the transmitter and receiver are perfectly synchronized in comparison to the existing state-of-the-art counterparts. Moreover, the corresponding CRLB of the proposed model represents almost about 20 dB reduction in the localization error bound in comparison with the previous model for some practical scenarios.
Tynell, Lena Lyngholt; Wimmelmann, Camilla Lawaetz; Jervelund, Signe Smith
2017-01-01
Objective: In most European countries, immigrants do not systematically learn about the host countries' healthcare system when arriving. This study investigated how newly arrived immigrants perceived the information they received about the Danish healthcare system. Methods: Immigrants attending a language school in Copenhagen in 2012 received…
Holographic p-wave superconductor models with Weyl corrections
Directory of Open Access Journals (Sweden)
Lu Zhang
2015-04-01
Full Text Available We study the effect of the Weyl corrections on the holographic p-wave dual models in the backgrounds of AdS soliton and AdS black hole via a Maxwell complex vector field model by using the numerical and analytical methods. We find that, in the soliton background, the Weyl corrections do not influence the properties of the holographic p-wave insulator/superconductor phase transition, which is different from that of the Yang–Mills theory. However, in the black hole background, we observe that similarly to the Weyl correction effects in the Yang–Mills theory, the higher Weyl corrections make it easier for the p-wave metal/superconductor phase transition to be triggered, which shows that these two p-wave models with Weyl corrections share some similar features for the condensation of the vector operator.
Abbattista, Teresa; Ridolfi, Francesco; Consalvo, Giovanni Traina; Brunelli, Eugenio
2016-10-01
To evaluate the performance of contrast-enhanced sonography with a second-generation contrast agent in assessing the severity of chronic diffuse liver disease and differentiating cirrhotic from noncirrhotic liver disease. Contrast-enhanced sonography was performed after intravenous bolus injection of a second-generation contrast agent in 14 healthy control participants and 160 consecutive patients with cirrhotic and noncirrhotic liver disease (n = 78 and 82, respectively) enrolled between March 2004 and April 2014. The intensity of enhancement in a main hepatic vein was used to determine hepatic vein arrival time, time to peak intensity, and peak contrast enhancement. The hepatic vein arrival time was lower in cirrhotic patients compared with both noncirrhotic patients and controls (mean ± SD, 15.0 ± 2.8, 21.5 ± 3.4, and 25.6 ± 4.7 seconds, respectively; P < .05). The hepatic vein arrival time in noncirrhotic patients was also significantly lower than that in controls (P < .05). The time to peak intensity was significantly lower in cirrhotic patients compared with noncirrhotic patients and controls (40.7 ± 13.7, 49.4 ± 12.8, and 51.2 ± 13.7 seconds; P < .05). A receiver operating characteristic curve analysis revealed that the hepatic vein arrival time more accurately excluded a diagnosis of liver cirrhosis than the time to peak intensity (area under the receiver operating characteristic curve, 0.953 versus 0.694). Specifically, a hepatic vein arrival time cutoff value of 17 seconds excluded liver cirrhosis with 91.1% sensitivity and 93.6% specificity. Contrast-enhanced sonography is a valid alternative method for noninvasive staging of liver diseases. The hepatic vein arrival time could be used to exclude liver cirrhosis in a clinical setting.
Fluid approximation analysis of a call center model with time-varying arrivals and after-call work
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Yosuke Kawai
2015-12-01
Full Text Available Important features to be included in queueing-theoretic models of the call center operation are multiple servers, impatient customers, time-varying arrival process, and operator’s after-call work (ACW. We propose a fluid approximation technique for the queueing model with these features by extending the analysis of a similar model without ACW recently developed by Liu and Whitt (2012. Our model assumes that the service for each quantum of fluid consists of a sequence of two stages, the first stage for the conversation with a customer and the second stage for the ACW. When the duration of each stage has exponential, hyperexponential or hypo-exponential distribution, we derive the time-dependent behavior of the content of fluid in each stage of service as well as that in the waiting room. Numerical examples are shown to illustrate the system performance for the cases in which the input rate and/or the number of servers vary in sinusoidal fashion as well as in adaptive ways and in stationary cases.
Simulation-based validation and arrival-time correction for Patlak analyses of Perfusion-CT scans
Bredno, Jörg; Hom, Jason; Schneider, Thomas; Wintermark, Max
2009-02-01
Blood-brain-barrier (BBB) breakdown is a hypothesized mechanism for hemorrhagic transformation in acute stroke. The Patlak analysis of a Perfusion Computed Tomography (PCT) scan measures the BBB permeability, but the method yields higher estimates when applied to the first pass of the contrast bolus compared to a delayed phase. We present a numerical phantom that simulates vascular and parenchymal time-attenuation curves to determine the validity of permeability measurements obtained with different acquisition protocols. A network of tubes represents the major cerebral arteries ipsi- and contralateral to an ischemic event. These tubes branch off into smaller segments that represent capillary beds. Blood flow in the phantom is freely defined and simulated as non-Newtonian tubular flow. Diffusion of contrast in the vessels and permeation through vessel walls is part of the simulation. The phantom allows us to compare the results of a permeability measurement to the simulated vessel wall status. A Patlak analysis reliably detects areas with BBB breakdown for acquisitions of 240s duration, whereas results obtained from the first pass are biased in areas of reduced blood flow. Compensating for differences in contrast arrival times reduces this bias and gives good estimates of BBB permeability for PCT acquisitions of 90-150s duration.
Neutron resonance spectroscopy on 113Cd: The p-wave levels
International Nuclear Information System (INIS)
Frankle, C.M.; Bowman, C.D.; Bowman, J.D.; Seestrom, S.J.; Sharapov, E.I.; Popov, Y.P.; Roberson, N.R.
1992-01-01
Weak levels in the compound nucleus 114 Cd were located by neutron time-of-flight spectroscopy techniques. Neutron capture measurements were performed with both a natural cadmium target and a highly enriched 113 Cd target. A total of 22 new resonances were located in the neutron energy interval 20-500 eV and were assumed to be p-wave. Resonance parameters, E 0 and gΓ n , are given for the newly identified levels. The p-wave strength function was determined to be 10 4 S 1 =2.8±0.8 and the average level spacing left-angle D 1 right-angle=14 eV. Comparison of the reduced widths with a Porter-Thomas distribution is consistent with having missed 15% of the p-wave levels
The offset-midpoint traveltime pyramid of P-waves in homogeneous orthorhombic media
Hao, Qi; Stovas, Alexey; Alkhalifah, Tariq Ali
2016-01-01
The offset-midpoint traveltime pyramid describes the diffraction traveltime of a point diffractor in homogeneous media. We have developed an analytic approximation for the P-wave offset-midpoint traveltime pyramid for homogeneous orthorhombic media. In this approximation, a perturbation method and the Shanks transform were implemented to derive the analytic expressions for the horizontal slowness components of P-waves in orthorhombic media. Numerical examples were shown to analyze the proposed traveltime pyramid formula and determined its accuracy and the application in calculating migration isochrones and reflection traveltime. The proposed offset-midpoint traveltime formula is useful for Kirchhoff prestack time migration and migration velocity analysis for orthorhombic media.
The offset-midpoint traveltime pyramid of P-waves in homogeneous orthorhombic media
Hao, Qi
2016-07-18
The offset-midpoint traveltime pyramid describes the diffraction traveltime of a point diffractor in homogeneous media. We have developed an analytic approximation for the P-wave offset-midpoint traveltime pyramid for homogeneous orthorhombic media. In this approximation, a perturbation method and the Shanks transform were implemented to derive the analytic expressions for the horizontal slowness components of P-waves in orthorhombic media. Numerical examples were shown to analyze the proposed traveltime pyramid formula and determined its accuracy and the application in calculating migration isochrones and reflection traveltime. The proposed offset-midpoint traveltime formula is useful for Kirchhoff prestack time migration and migration velocity analysis for orthorhombic media.
A P-wave velocity model of the upper crust of the Sannio region (Southern Apennines, Italy
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M. Cocco
1998-06-01
Full Text Available This paper describes the results of a seismic refraction profile conducted in October 1992 in the Sannio region, Southern Italy, to obtain a detailed P-wave velocity model of the upper crust. The profile, 75 km long, extended parallel to the Apenninic chain in a region frequently damaged in historical time by strong earthquakes. Six shots were fired at five sites and recorded by a number of seismic stations ranging from 41 to 71 with a spacing of 1-2 km along the recording line. We used a two-dimensional raytracing technique to model travel times and amplitudes of first and second arrivals. The obtained P-wave velocity model has a shallow structure with strong lateral variations in the southern portion of the profile. Near surface sediments of the Tertiary age are characterized by seismic velocities in the 3.0-4.1 km/s range. In the northern part of the profile these deposits overlie a layer with a velocity of 4.8 km/s that has been interpreted as a Mesozoic sedimentary succession. A high velocity body, corresponding to the limestones of the Western Carbonate Platform with a velocity of 6 km/s, characterizes the southernmost part of the profile at shallow depths. At a depth of about 4 km the model becomes laterally homogeneous showing a continuous layer with a thickness in the 3-4 km range and a velocity of 6 km/s corresponding to the Meso-Cenozoic limestone succession of the Apulia Carbonate Platform. This platform appears to be layered, as indicated by an increase in seismic velocity from 6 to 6.7 km/s at depths in the 6-8 km range, that has been interpreted as a lithological transition from limestones to Triassic dolomites and anhydrites of the Burano formation. A lower P-wave velocity of about 5.0-5.5 km/s is hypothesized at the bottom of the Apulia Platform at depths ranging from 10 km down to 12.5 km; these low velocities could be related to Permo-Triassic siliciclastic deposits of the Verrucano sequence drilled at the bottom of the Apulia
Energy Technology Data Exchange (ETDEWEB)
Ma, Jian; Casey, Cameron P.; Zheng, Xueyun; Ibrahim, Yehia M.; Wilkins, Christopher S.; Renslow, Ryan S.; Thomas, Dennis G.; Payne, Samuel H.; Monroe, Matthew E.; Smith, Richard D.; Teeguarden, Justin G.; Baker, Erin S.; Metz, Thomas O.
2017-05-15
Motivation: Drift tube ion mobility spectrometry (DTIMS) is increasingly implemented in high throughput omics workflows, and new informatics approaches are necessary for processing the associated data. To automatically extract arrival times for molecules measured by DTIMS coupled with mass spectrometry and compute their associated collisional cross sections (CCS) we created the PNNL Ion Mobility Cross Section Extractor (PIXiE). The primary application presented for this algorithm is the extraction of information necessary to create a reference library containing accu-rate masses, DTIMS arrival times and CCSs for use in high throughput omics analyses. Results: We demonstrate the utility of this approach by automatically extracting arrival times and calculating the associated CCSs for a set of endogenous metabolites and xenobiotics. The PIXiE-generated CCS values were identical to those calculated by hand and within error of those calcu-lated using commercially available instrument vendor software.
International Nuclear Information System (INIS)
Inoue, N.; Kaneko, T.; Yoshii, H.
1985-01-01
The longitudinal development of electrons in extensive air showers before the maximum has been studied by measuring the arrival time distributions of atmospheric Cerenkov light from air showers, with primary energies in the range 6 x 10 15 to 2 x 10 17 eV, in the Chacaltaya air-shower array. These arrival time distributions are consistent with those calculated using a model of particle interactions which contain Feynman scaling in the fragmentation region, an Esup(1/2) multiplicity law in the pionisation region and a rising cross section for primary protons. Such a model also reproduces the arrival time distributions of Cerenkov light measured in the Akeno air-shower array as described in the preceding paper, which implies a very fast development before the maximum and a slow development after the maximum. (author)
International Nuclear Information System (INIS)
Laros, J.G.; Hurley, K.C.; Fenimore, E.E.; Klebesadel, R.W.; Briggs, M.S.; Kouveliotou, C.; McCollough, M.L.; Fishman, G.J.; Meegan, C.A.; Cline, T.L.; Boer, M.; Niel, M.
1998-01-01
Between the Compton Gamma Ray Observatory (CGRO) launch in 1991 April and the Pioneer Venus Orbiter (PVO) demise in 1992 October, concurrent coverage by CGRO, PVO, and Ulysses was obtained for several hundred gamma-ray bursts (GRBs). Although most of these were below the PVO and Ulysses thresholds, 37 were positively detected by all three spacecraft, with data quality adequate for quantitative localization analysis. All were localized independently to ∼2 degree accuracy by the CGRO Burst and Transient Source Experiment (BATSE), and three were also localized by COMPTEL. We computed arrival-time error boxes, whose larger dimensions range from about 2' to several degrees and whose smaller dimensions are in the arcminute range. Twelve have areas less than 10 arcmin 2 , and only four have areas greater than 1 deg 2 . The area of the smallest box is 0.44 arcmin 2 . We find that the overall BATSE localization accuracy for these events is consistent with the most recent stated uncertainties. This work indicates that the ROSAT soft X-ray source found within a preliminary IPN error box for GB920501 (Trig 1576) (Hurley et al.) is less likely to be the GRB counterpart than previously reported. copyright copyright 1998. The American Astronomical Society
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Eugenio Marino Merlo
2017-10-01
Full Text Available Composite material structures are commonly used in many industrial sectors (aerospace, automotive, transportation, and can operate in harsh environments where impacts with other parts or debris may cause critical safety and functionality issues. This work presents a method for improving the accuracy of impact position determination using acoustic source triangulation schemes based on the data collected by piezoelectric sensors attached to the structure. A novel approach is used to estimate the Differential Time-of-Arrival (DToA between the impact response signals collected by a triplet of sensors, overcoming the limitations of classical methods that rely on amplitude thresholds calibrated for a specific sensor type. An experimental evaluation of the proposed technique was performed with specially made circular piezopolymer (PVDF sensors designed for Structural Health Monitoring (SHM applications, and compared with commercial piezoelectric SHM sensors of similar dimensions. Test impacts at low energies from 35 mJ to 600 mJ were generated in a laboratory by free-falling metal spheres on a 500 mm × 500 mm × 1.25 mm quasi-isotropic Carbon Fiber Reinforced Polymer (CFRP laminate plate. From the analysis of many impact signals, the resulting localization error was improved for all types of sensors and, in particular, for the circular PVDF sensor an average error of 20.3 mm and a standard deviation of 8.9 mm was obtained.
Muehlsteff, J; Aubert, X A; Morren, G
2008-01-01
There is an unmet need for cuff-less blood pressure (BP) monitoring especially, in personal healthcare applications. The pulse arrival time (PAT) approach might offer a suitable solution to enable comfortable BP monitoring even at beat-level. However, the methodology is based on hemodynamic surrogate measures, which are sensitive to patient activities such as posture changes, not necessarily related to blood pressure variations. In this paper, we analyze the impact of posture on the PAT measure and related hemodynamic parameters such as the pre-ejection period in well-defined procedures. Additionally, the PAT of a monitored subject is investigated in an unsupervised scenario illustrating the complexity of such a measurement. Our results show the failure of blood pressure inference based on simple calibration strategies using the PAT measure only. We discuss opportunities to compensate for the observed effects towards the realization of wearable cuff-less blood pressure monitoring. These findings emphasize the importance of accessing context information in personal healthcare applications, where vital sign monitoring is typically unsupervised.
International Nuclear Information System (INIS)
Almoza, Yeleine; Grimaldi, Salvador; Petroseli, Andrea; Santini, Monia; Nardi, Fernando
2008-01-01
Full text: Physics is closely related to the other natural sciences, and in certain mode covers all. For example, the geomorphology; hydrogeology and other so many branches of Physical geography, linking this science in the modelling of phenomena related with them. Watersheds are areas than by their topographic features are they identify and differ from other types of relief. Specifically in the Rigo basin of the region of Lazio, Italy, relief - flow of water - time relationship, was characterized by the physical relationship T = S/V where T is the time that it takes the water flow produced by a rain event on reaching the mouth or basin (sec.) limit, given the length is the flow to the mouth (m) and V is the speed you can have flow on the land (m/s). The determination of this time is of utmost importance in agriculture and in General for the management of natural disasters of character hydrological, by losses Economic and material which may cause large avenues of water flow in a way surprising and unexpected. Therefore the overall objective of this study is to determine the map of time of arrival of the flow along the entire basin Rigo to the mouth. In addition It has a target specific, compare two maps of time, one normally calculated with the variable speed in the field and another with constant speed. These physical magnitudes T, S, V, were determined in the information system Geographic ArcGIS 9.2 with ArcINFO extension, in an atmosphere of macro language AML of programming, on the basis of the model Digital of elevation (DEM) of the basin Rigo. Then is they were calculating on scales of pixels of 30 meters, different topographic attributes and hydrological. The determination of these attributes as the direction of the flow, Areas Cumulative drainage, drainage network, Horton parameters, among others were used to calculate per unit of map the length of the flow (S) to the mouth. Was subsequently calculated the speed the flow map on the ground since the law of
Arrival-time distribution of muons in extensive air showers at energies of 1017 eV to 1018 eV
International Nuclear Information System (INIS)
Blake, P.R.; Mann, D.M.; Nash, W.F.; O'Connell, B.; Strutt, R.B.
1982-01-01
The results of measurements of the rise-time of muon scintillator responses recorded from extensive air showers detected at Haverah Park are described. A high-speed storage oscilloscope recording system has been used to study both the average characteristics of muon time spreads and the fluctuations in arrival-time distributions between individual showers. The average muon time spreads are found to be a function of core distance, zenith angle and muon threshold energy. There is evidence that velocity delays are an important contribution to the muon rise-times for detectors with threshold energies < approximately 500 MeV. Significant fluctuations in the muon time spreads between individual showers are found. The average characteristics of the muon arrival-time distributions are also compared with the shower computer simulations. (author)
p-wave pion production from nucleon-nucleon collisions
International Nuclear Information System (INIS)
Baru, V.; Epelbaum, E.; Haidenbauer, J.; Hanhart, C.; Kudryavtsev, A. E.; Lensky, V.; Meissner, U.-G.
2009-01-01
We investigate p-wave pion production in nucleon-nucleon collisions up to next-to-next-to-leading order in chiral effective field theory. In particular, we show that it is possible to describe simultaneously the p-wave amplitudes in the pn→ppπ - , pp→pnπ + , pp→dπ + channels by adjusting a single low-energy constant accompanying the short-range operator that is available at this order. This study provides a nontrivial test of the applicability of chiral effective field theory to reactions of the type NN→NNπ.
Unal Guntekin; Yilmaz Gunes; Hakki Simsek; Mustafa Tuncer; Sevket Arslan
2009-01-01
Background: Prolonged P wave duration and P wave dispersion (PWD) have been associated with an increased risk for atrial fibrillation (AF). Hyperthytodism is a frequent cause of atrial fibrillation (AF). Methods: Forty-two patients with newly diagnosed overt hyperthyroidism and 20 healthy people were enrolled in the study. Transthoracic echocardiography, 12 lead surface ECG and thyroid hormone levels were studied at the time of enrollment and after achievement of euthyroid state with propylth...
Correlating P-wave Velocity with the Physico-Mechanical Properties of Different Rocks
Khandelwal, Manoj
2013-04-01
In mining and civil engineering projects, physico-mechanical properties of the rock affect both the project design and the construction operation. Determination of various physico-mechanical properties of rocks is expensive and time consuming, and sometimes it is very difficult to get cores to perform direct tests to evaluate the rock mass. The purpose of this work is to investigate the relationships between the different physico-mechanical properties of the various rock types with the P-wave velocity. Measurement of P-wave velocity is relatively cheap, non-destructive and easy to carry out. In this study, representative rock mass samples of igneous, sedimentary, and metamorphic rocks were collected from the different locations of India to obtain an empirical relation between P-wave velocity and uniaxial compressive strength, tensile strength, punch shear, density, slake durability index, Young's modulus, Poisson's ratio, impact strength index and Schmidt hammer rebound number. A very strong correlation was found between the P-wave velocity and different physico-mechanical properties of various rock types with very high coefficients of determination. To check the sensitivity of the empirical equations, Students t test was also performed, which confirmed the validity of the proposed correlations.
International Nuclear Information System (INIS)
Banghar, A.R.
1980-01-01
As a part of programme of seismic detection of underground nuclear explosions, step by step variations in the amplitude spectra and waveforms of P wave signal, as it propagates from source to receiver region, are investigated. Influences on the amplitude spectra and waveforms of teleseismic p waves due to : (1) variation in the shape of reduced displacement potential, (2) variation of mantle Q values, (3) change in depth, (4) various yields, (5) spalling, and (6) variation of crustal structure at source as well as at receiver are studied. The results show that for a yield of 85 kilotons, the time structure of seismograms is nearly same for four types of reduced displacement potentials considered here. The duration of waveforms is affected both by crustal structure at source as well as due to spalling. In general, effect of receiver crust on seismograms is found to be minor. Synthesized and observed P wave seismograms for Longshot, Milrow and Cannikin underground nuclear explosions are computed at various seismometer array stations of the UKAEA. Computed seismograms compare well with the recorded ones. It is seen that: (1) overburden P wave velocity inferred from seismograms is less as compared to its value obtained from on-site measurements, and (2) the source function, the source crust transfer function, the mantle transfer function and the spalling function are the most important factors that influence shaping of spectra and seismograms. (M.G.B.)
Magnetic manipulation of topological states in p-wave superconductors
DEFF Research Database (Denmark)
Mercaldo, Maria Teresa; Cuoco, Mario; Kotetes, Panagiotis
2018-01-01
Substantial experimental investigation has provided evidence for spin-triplet pairing in diverse classes of materials and in a variety of artificial heterostructures. One of the fundamental challenges in this framework is how to manipulate the topological behavior of p-wave superconductors (PSC...
Genetic determinants of P wave duration and PR segment
Verweij, Niek; Mateo Leach, Irene; van den Boogaard, Malou; van Veldhuisen, Dirk J.; Christoffels, Vincent M.; Hillege, Hans L.; van Gilst, Wiek H.; Barnett, Phil; de Boer, Rudolf A.; van der Harst, Pim
2014-01-01
The PR interval on the ECG reflects atrial depolarization and atrioventricular nodal delay which can be partially differentiated by P wave duration and PR segment, respectively. Genome-wide association studies have identified several genetic loci for PR interval, but it remains to be determined
Genetic Determinants of P Wave Duration and PR Segment
Verweij, Niek; Mateo Leach, Irene; van den Boogaard, Malou; van Veldhuisen, Dirk J.; Christoffels, Vincent M.; Hillege, Hans L.; van Gilst, Wiek H.; Barnett, Phil; de Boer, Rudolf A.; van der Harst, Pim
Background-The PR interval on the ECG reflects atrial depolarization and atrioventricular nodal delay which can be partially differentiated by P wave duration and PR segment, respectively. Genome-wide association studies have identified several genetic loci for PR interval, but it remains to be
Arrival metering fuel consumption analysis
2011-01-01
Arrival metering is a method of time-based traffic management that is used by the Federal Aviation Administration to plan and manage streams of arrival traffic during periods of : high demand at busy airports. The Traffic Management Advisor is an aut...
Directory of Open Access Journals (Sweden)
W. Sun
Full Text Available The Sun was extremely active during the "April Fool’s Day" epoch of 2001. We chose this period between a solar flare on 28 March 2001 to a final shock arrival at Earth on 21 April 2001. The activity consisted of two presumed helmet-streamer blowouts, seven M-class flares, and nine X-class flares, the last of which was behind the west limb. We have been experimenting since February 1997 with real-time, end-to-end forecasting of interplanetary coronal mass ejection (ICME shock arrival times. Since August 1998, these forecasts have been distributed in real-time by e-mail to a list of interested scientists and operational USAF and NOAA forecasters. They are made using three different solar wind models. We describe here the solar events observed during the April Fool’s 2001 epoch, along with the predicted and actual shock arrival times, and the ex post facto correction to the real-time coronal shock speed observations. It appears that the initial estimates of coronal shock speeds from Type II radio burst observations and coronal mass ejections were too high by as much as 30%. We conclude that a 3-dimensional coronal density model should be developed for application to observations of solar flares and their Type II radio burst observations.
Key words. Interplanetary physics (flare and stream dynamics; interplanetary shocks – Magnetosheric physics (storms and substorms
Kakimoto, F.; Tsuchimoto, I.; Enoki, T.; Suga, K.; Nishi, K.
1985-01-01
Detection of air showers with primary energies above 10 to the 19th power eV with sufficient statistics is extremely important in an astrophysical aspect related to the Greisen cut off and the origin of such high energy cosmic rays. Recently, a method is proposed to observe such giant air showers by measuring the arrival time distributions of air-shower particles at large core distances with a mini array. Experiments to measure the arrival time distributions of muons were started in 1981 and those of electrons in early 1983 in the Akeno air-shower array (930 gcm cm squared atmospheric depth, 900m above sea level). During the time of observation, the detection area of the Akeno array was expanded from 1 sq km to sq km in 1982 and to 20 sq km in 1984. Now the arrival time distribution of electrons and muons can be measured for showers with primary energies above 1019eV at large core distances.
C. M. Scoby; P. Musumeci; J. T. Moody; M. S. Gutierrez
2010-01-01
In this paper we study a new geometry setup for electro-optic sampling (EOS) where the electron beam runs parallel to the ⟨110⟩ face of a ZnTe crystal and the probe laser is perpendicular to it and to the beam path. The simple setup is used to encode the time-of-arrival information of a 3.5 MeV
Statistical analysis of P-wave neutron reduced widths
International Nuclear Information System (INIS)
Joshi, G.C.; Agrawal, H.M.
2000-01-01
The fluctuations of the p-wave neutron reduced widths for fifty one nuclei have been analyzed with emphasis on recent measurements by a statistical procedure which is based on the method of maximum likelihood. It is shown that the p-wave neutron reduced widths of even-even nuclei fallow single channel Porter Thomas distribution (χ 2 -distribution with degree of freedom ν=1) for most of the cases where there are no intermediate structure. It is emphasized that the distribution in nuclei other than even-even may differ from a χ 2 -distribution with one degree of freedom. Possible explanation and significance of this deviation from ν=1 is given. (author)
Directory of Open Access Journals (Sweden)
S. M. P. McKenna-Lawlor
2002-07-01
Full Text Available The arrival times at L1 of eleven travelling shocks associated both with X-ray flaring and with halo CMEs recorded aboard SOHO/LASCO have been considered. Close to the Sun the velocities of these events were estimated using either Type II radio records or CME speeds. Close to the Earth the shocks were detected in the data of various solar wind plasma, interplanetary magnetic field (IMF and energetic particle experiments aboard SOHO, ACE, WIND, INTERBALL-1 and IMP-8. The real-time shock arrival predictions of three numerical models, namely the Shock Time of Arrival Model (STOA, the Interplanetary Shock Propagation Model (ISPM and the Hakamada-Akasofu-Fry Solar Wind Model (HAFv.2 were tested against these observations. This is the first time that energetic protons (tens of keV to a few MeV have been used to complement plasma and IMF data in validating shock propagation models. The models were all generally successful in predicting shock arrivals. STOA provided the smallest values of the "predicted minus measured" arrival times and displayed a typical predictive precision better than about 8 h. The ratio of the calculated standard deviation of the transit times to Earth to the standard deviation of the measurements was estimated for each model (treating interacting events as composite shocks and these ratios turned out to be 0.60, 1.15 and 1.02 for STOA, ISPM and HAFv.2, respectively. If an event in the sample for which the shock velocity was not well known is omitted from consideration, these ratios become 0.36, 0.76 and 0.81, respectively. Larger statistical samples should now be tested. The ratio of the in situ shock velocity and the "Sun to L1" transit velocity (Vsh /Vtr was in the range of 0.7–0.9 for individual, non-interacting, shock events. HAFv.2 uniquely provided information on those changes in the COBpoint (the moving Connection point on the shock along the IMF to the OBserver which directly influenced energetic particle rise times
Renormalization group approach to a p-wave superconducting model
International Nuclear Information System (INIS)
Continentino, Mucio A.; Deus, Fernanda; Caldas, Heron
2014-01-01
We present in this work an exact renormalization group (RG) treatment of a one-dimensional p-wave superconductor. The model proposed by Kitaev consists of a chain of spinless fermions with a p-wave gap. It is a paradigmatic model of great actual interest since it presents a weak pairing superconducting phase that has Majorana fermions at the ends of the chain. Those are predicted to be useful for quantum computation. The RG allows to obtain the phase diagram of the model and to study the quantum phase transition from the weak to the strong pairing phase. It yields the attractors of these phases and the critical exponents of the weak to strong pairing transition. We show that the weak pairing phase of the model is governed by a chaotic attractor being non-trivial from both its topological and RG properties. In the strong pairing phase the RG flow is towards a conventional strong coupling fixed point. Finally, we propose an alternative way for obtaining p-wave superconductivity in a one-dimensional system without spin–orbit interaction.
P-wave dispersion in endogenous and exogenous subclinical hyperthyroidism.
Gen, R; Akbay, E; Camsari, A; Ozcan, T
2010-02-01
The aim of this study was to measure maximum P wave duration (Pmax) and P wave dispersion (PWD), which can be indicators for the risk of paroxysmal atrial fibrillation when increased, and to reveal their relationship with thyroid hormone levels in patients with endogenous and exogenous subclinical hyperthyroidism. Seventy-one patients with sublinical thyrotoxicosis (34 endogenous, 37 exogenous) and 69 healthy individuals were enrolled in the study. Pmax and minimum P wave duration (Pmin) on electrocardiogram recordings were measured and PWD was calculated as Pmax-Pmin. Pmax (pendogenous subclinical hyperthyroidism compared with the control group. Pmax (pexogenous subclinical thyrotoxicosis compared with the control group. Pmax (p=0.710) and PWD (p=0.127) were not significantly different in patients with endogenous subclinical hyperthyroidism compared with exogenous subclinical hyperthyroid patients. Pmax and PWD negatively associated with TSH in endogenous and exogenous subclinical hyperthyroidism. In the present study, we observed that Pmax and PWD were longer in patients with endogenous and exogenous subclinical hyperthyroidism. Lack of a difference in Pmax and PWD between patients with endogenous and exogenous subclinical hyperthyroidism seems to support the idea that hormone levels rather than the etiology of thyrotoxicosis affect the heart.
P-wave assignment of 232Th neutron resonances
International Nuclear Information System (INIS)
Corvi, F.; Pasquariello, G.; Veen, T. van der
1978-01-01
A method of p-wave assignment which exploits the parity dependence of the primary capture γ-ray spectrum was applied to the 232 Th resonance. The yield of capture γ-rays above 4.4 MeV from a 6 mm thick metallic thorium disk was measured in the neutron energy range 20-2200 eV and compared to a similar run with γ-rays in the range 3.7 - 4.4 MeV. A total of 58 resonances showing an enhancement of the high energy γ-ray yield were assigned as p-waves. Assuming that their reduced neutron widths follow a Porter-Thomas distribution, their average value and then the p-wave strength function S 1 were estimated with a maximum likelihood method. The results are: average neutron width=3.4(+0.8 or -0.6)meV; S 1 = 2.0 (+0.5 or -0.4).10 -4
Probing the P -wave charmonium decays of Bc meson
Rui, Zhou
2018-02-01
Motivated by the large number of Bc meson decay modes observed recently by several detectors at the LHC, we present a detailed analysis of the Bc meson decaying to the P -wave charmonium states and a light pseudoscalar (P ) or vector (V ) meson within the framework of perturbative QCD factorization. The P -wave charmonium distribution amplitudes are extracted from the n =2 , l =1 Schrödinger states for a Coulomb potential, which can be taken as the universal nonperturbative objects to analyze the hard exclusive processes with P -wave charmonium production. It is found that these decays have large branching ratios of the order of 10-5˜10-2 , which seem to be in the reach of future experiments. We also provide predictions for the polarization fractions and relative phases of Bc→(χc 1,χc 2,hc)V decays. It is expected that the longitudinal polarization amplitudes dominate the branching ratios according to the quark helicity analysis, and the magnitudes and phases of parallel polarization amplitude are approximately equal to the perpendicular ones. The obtained results are compared with available experimental data, our previous studies, and numbers from other approaches.
P-wave scattering and the distribution of heterogeneity around Etna volcano
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Toni Zieger
2016-09-01
Full Text Available Volcanoes and fault zones are areas of increased heterogeneity in the Earth crust that leads to strong scattering of seismic waves. For the understanding of the volcanic structure and the role of attenuation and scattering processes it is important to investigate the distribution of heterogeneity. We used the signals of air-gun shots to investigate the distribution of heterogeneity around Mount Etna. We devise a new methodology that is based on the coda energy ratio which we define as the ratio between the energy of the direct P-wave and the energy in a later coda window. This is based on the basic assumption that scattering caused by heterogeneity removes energy from the direct P-waves. We show that measurements of the energy ratio are stable with respect to changes of the details of the time windows definitions. As an independent proxy of the scattering strength along the ray path we measure the peak delay time of the direct P-wave. The peak delay time is well correlated with the coda energy ratio. We project the observation in the directions of the incident rays at the stations. Most notably is an area with increased wave scattering in the volcano and east of it. The strong heterogeneity found supports earlier observations and confirms the possibility to use P-wave sources for the determination of scattering properties. We interpret the extension of the highly heterogeneous zone towards the east as a potential signature of inelastic deformation processes induced by the eastward sliding of flank of the volcano.
P Wave Dispersion is Increased in Pulmonary Stenosis
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Namik Ozmen
2006-01-01
Full Text Available Aim: The right atrium pressure load is increased in pulmonary stenosis (PS that is a congenital anomaly and this changes the electrophysiological characteristics of the atria. However, there is not enough data on the issue of P wave dispersion (PWD in PS. Methods: Forty- two patients diagnosed as having valvular PS with echocardiography and 33 completely healthy individuals as the control group were included in the study. P wave duration, p wave maximum (p max and p minimum (p min were calculated from resting electrocariography (ECG obtained at the rate of 50 mm/sec. P wave dispersion was derived by subtracting p min from p max. The mean pressure gradient (MPG at the pulmonary valve, structure of the valve and diameters of the right and left atria were measured with echocardiography. The data from two groups were compared with the Mann-Whitney U test and correlation analysis was performed with the Pearson correlation technique. Results: There wasn’t any statistically significance in the comparison of age, left atrial diameter and p min between two groups. While the MPG at the pulmonary valve was 43.11 ± 18.8 mmHg in PS patients, it was 8.4 ± 4.5 mmHg in the control group. While p max was 107.1 ± 11.5 in PS group, it was 98.2 ± 5.1 in control group (p=0.01, PWD was 40.4 ± 1.2 in PS group, and 27.2 ± 9.3 in the control group (p=0.01Moreover, while the diameter of the right atrium in PS group was greater than that of the control group, (38.7 ± 3.9 vs 30.2 ± 2.5, p=0.02. We detected a correlation between PWD and pressure gradient in regression analysis. Conclusion: P wave dispersion and p max are increased in PS. While PWD was correlated with the pressure gradient that is the degree of narrowing, it was not correlated with the diameters of the right and left atria.
Alcaraz, Raúl; Martínez, Arturo; Rieta, José J
2015-04-01
A normal cardiac activation starts in the sinoatrial node and then spreads throughout the atrial myocardium, thus defining the P-wave of the electrocardiogram. However, when the onset of paroxysmal atrial fibrillation (PAF) approximates, a highly disturbed electrical activity occurs within the atria, thus provoking fragmented and eventually longer P-waves. Although this altered atrial conduction has been successfully quantified just before PAF onset from the signal-averaged P-wave spectral analysis, its evolution during the hours preceding the arrhythmia has not been assessed yet. This work focuses on quantifying the P-wave spectral content variability over the 2h preceding PAF onset with the aim of anticipating as much as possible the arrhythmic episode envision. For that purpose, the time course of several metrics estimating absolute energy and ratios of high- to low-frequency power in different bands between 20 and 200Hz has been computed from the P-wave autoregressive spectral estimation. All the analyzed metrics showed an increasing variability trend as PAF onset approximated, providing the P-wave high-frequency energy (between 80 and 150Hz) a diagnostic accuracy around 80% to discern between healthy subjects, patients far from PAF and patients less than 1h close to a PAF episode. This discriminant power was similar to that provided by the most classical time-domain approach, i.e., the P-wave duration. Furthermore, the linear combination of both metrics improved the diagnostic accuracy up to 88.07%, thus constituting a reliable noninvasive harbinger of PAF onset with a reasonable anticipation. The information provided by this methodology could be very useful in clinical practice either to optimize the antiarrhythmic treatment in patients at high-risk of PAF onset and to limit drug administration in low risk patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Application of perturbation theory to a P-wave eikonal equation in orthorhombic media
Stovas, Alexey
2016-10-12
The P-wave eikonal equation for orthorhombic (ORT) anisotropic media is a highly nonlinear partial differential equation requiring the solution of a sixth-order polynomial to obtain traveltimes, resulting in complex and time-consuming numerical solutions. To alleviate this complexity, we approximate the solution of this equation by applying a multiparametric perturbation approach. We also investigated the sensitivity of traveltime surfaces inORT mediawith respect to three anelliptic parameters. As a result, a simple and accurate P-wave traveltime approximation valid for ORT media was derived. Two different possible anelliptic parameterizations were compared. One of the parameterizations includes anelliptic parameters defined at zero offset: η1, η2, and ηxy. Another parameterization includes anelliptic parameters defined for all symmetry planes: η1, η2, and η3. The azimuthal behavior of sensitivity coefficients with different parameterizations was used to analyze the crosstalk between anelliptic parameters. © 2016 Society of Exploration Geophysicists.
Scattered P'P' waves observed at short distances
Earle, Paul S.; Rost, Sebastian; Shearer, Peter M.; Thomas, Christine
2011-01-01
We detect previously unreported 1 Hz scattered waves at epicentral distances between 30° and 50° and at times between 2300 and 2450 s after the earthquake origin. These waves likely result from off-azimuth scattering of PKPbc to PKPbc in the upper mantle and crust and provide a new tool for mapping variations in fine-scale (10 km) mantle heterogeneity. Array beams from the Large Aperture Seismic Array (LASA) clearly image the scattered energy gradually emerging from the noise and reaching its peak amplitude about 80 s later, and returning to the noise level after 150 s. Stacks of transverse versus radial slowness (ρt, ρr) show two peaks at about (2, -2) and (-2,-2) s/°, indicating the waves arrive along the major arc path (180° to 360°) and significantly off azimuth. We propose a mantle and surface PKPbc to PKPbc scattering mechanism for these observations because (1) it agrees with the initiation time and distinctive slowness signature of the scattered waves and (2) it follows a scattering path analogous to previously observed deep-mantle PK•KP scattering (Chang and Cleary, 1981). The observed upper-mantle scattered waves and PK•KP waves fit into a broader set of scattered waves that we call P′•d•P′, which can scatter from any depth, d, in the mantle.
Ichinose, G.; Woods, M.; Dwyer, J.
2014-03-01
We estimated the network-averaged mantle attenuation t*(total) of 0.5 s beneath the North Korea test site (NKTS) by use of P-wave spectra and normalized spectral stacks from the 25 May 2009 declared nuclear test (mb 4.5; IDC). This value was checked using P-waves from seven deep (580-600 km) earthquakes (4.8 test, which confirms the equality with the sum of t*(u) and t*(d). We included constraints on seismic moment, depth, and radiation pattern by using results from a moment tensor analysis and corner frequencies from modeling of P-wave spectra recorded at local distances. We also avoided finite-faulting effects by excluding earthquakes with complex source time functions. We assumed ω2 source models for earthquakes and explosions. The mantle attenuation beneath the NKTS is clearly different when compared with the network-averaged t* of 0.75 s for the western US and is similar to values of approximately 0.5 s for the Semipalatinsk test site within the 0.5-2 Hz range.
Dynamics of skyrmions and edge states in the resistive regime of mesoscopic p-wave superconductors
Energy Technology Data Exchange (ETDEWEB)
Fernández Becerra, V., E-mail: VictorLeonardo.FernandezBecerra@uantwerpen.be; Milošević, M.V., E-mail: milorad.milosevic@uantwerpen.be
2017-02-15
Highlights: • Voltage–current characterization of a mesoscopic p-wave superconducting sample. • Skyrmions and edge states are stabilized with an out-of-plane applied magnetic field. • In the resistive regime, moving skyrmions and the edge state behave distinctly different from the conventional kinematic vortices. - Abstract: In a mesoscopic sample of a chiral p-wave superconductor, novel states comprising skyrmions and edge states have been stabilized in out-of-plane applied magnetic field. Using the time-dependent Ginzburg–Landau equations we shed light on the dynamic response of such states to an external applied current. Three different regimes are obtained, namely, the superconducting (stationary), resistive (non-stationary) and normal regime, similarly to conventional s-wave superconductors. However, in the resistive regime and depending on the external current, we found that moving skyrmions and the edge state behave distinctly different from the conventional kinematic vortex, thereby providing new fingerprints for identification of p-wave superconductivity.
Castellaro, Marco; Peruzzo, Denis; Mehndiratta, Amit; Pillonetto, Gianluigi; Petersen, Esben Thade; Golay, Xavier; Chappell, Michael A; Bertoldo, Alessandra
2015-12-01
QUASAR arterial spin labeling (ASL) permits the application of deconvolution approaches for the absolute quantification of cerebral perfusion. Currently, oscillation index regularized singular value decomposition (oSVD) combined with edge-detection (ED) is the most commonly used method. Its major drawbacks are nonphysiological oscillations in the impulse response function and underestimation of perfusion. The aim of this work is to introduce a novel method to overcome these limitations. A system identification method, stable spline (SS), was extended to address ASL peculiarities such as the delay in arrival of the arterial blood in the tissue. The proposed framework was compared with oSVD + ED in both simulated and real data. SS was used to investigate the validity of using a voxel-wise tissue T1 value instead of using a single global value (of blood T1 ). SS outperformed oSVD + ED in 79.9% of simulations. When applied to real data, SS exhibited a physiologically realistic range for perfusion and a higher mean value with respect to oSVD + ED (55.5 ± 9.5 SS, 34.9 ± 5.2 oSVD + ED mL/100 g/min). SS can represent an alternative to oSVD + ED for the quantification of QUASAR ASL data. Analysis of the retrieved impulse response function revealed that using a voxel wise tissue T1 might be suboptimal. © 2014 Wiley Periodicals, Inc.
The Relationship Between Aging and P Wave Dispersion
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İrfan Barutçu
2009-12-01
Full Text Available Objective: Atrial fibrillation (AF, commonly observed in advanced ages, displays striking age dependent increase and increased P wave dispersion (PWD has been shown to be a predictor of AF. In this studywe sought to determine whether P wave duration and PWD increase with aging. Method and Results: Eighty-three elderly subjects (group-I mean age 75±8 years and 40 healthy young subjects (group-II, mean age 37±6 years participated in this study. 12-lead ECG recorded at a paper speed of 50mm/s was obtained from each participant. Maximum (Pmax and minimum P wave duration (Pmin was measured manually with a caliper and the difference between two values was defined asPWD. Pmax and PWD were significantly higher in group-I compared to group-II. (98±8 vs. 93±8 p=0.01, 41±12 vs. 34±13 p=0.002, respectively. Among the elderly population when those with cardiovascular disorders such as hypertension, coronary artery disease and heart failure were excluded, Pmax and PWD were still significantly higher than the young population. (Pmax: 98±7 vs. 93±7, p=0.02 and PWD: 42±11 vs. 34±13, p=0.002. Moreover, on correlation analysis a positive correlation was detected between Pmaxand PWD and aging. (r=0.29, p=0.004; r=0.30, p=0.003 respectively.Conclusion: PWD shows age dependent increase and may be a useful marker for estimation the risk of developing AF seen in advanced ages.
P-wave Feshbach resonances of ultracold 6Li
International Nuclear Information System (INIS)
Zhang, J.; Kempen, E.G.M. van; Bourdel, T.; Cubizolles, J.; Chevy, F.; Teichmann, M.; Tarruell, L.; Salomon, C.; Khaykovich, L.; Kokkelmans, S.J.J.M.F.
2004-01-01
We report the observation of three p-wave Feshbach resonances of 6 Li atoms in the lowest hyperfine state f=1/2. The positions of the resonances are in good agreement with theory. We study the lifetime of the cloud in the vicinity of the Feshbach resonances and show that, depending on the spin states, two- or three-body mechanisms are at play. In the case of dipolar losses, we observe a nontrivial temperature dependence that is well explained by a simple model
Guntekin, Unal; Gunes, Yilmaz; Simsek, Hakki; Tuncer, Mustafa; Arslan, Sevket
2009-09-01
Prolonged P wave duration and P wave dispersion (PWD) have been associated with an increased risk for atrial fibrillation (AF). Hyperthytodism is a frequent cause of atrial fibrillation (AF). Forty-two patients with newly diagnosed overt hyperthyroidism and 20 healthy people were enrolled in the study. Transthoracic echocardiography, 12 lead surface ECG and thyroid hormone levels were studied at the time of enrollment and after achievement of euthyroid state with propylthiouracil treatment. Maximum P wave duration (Pmax) (97.4+/-14.6 vs. 84.2+/-9.5 msec, phyperthyroid patients compared to control group. Pmax and PWD were significantly correlated with the presence of hyperthyroidism. Pmax (97.4+/-14.6 to 84.3+/-8.6 msec, phyperthyroidism. Diastolic dyfunction was seen in 5 patients at hyperthroid state but only in one patient at euthyroid state. Hyperthyroidism is associated with prolonged P wave duration and dispersion. Achievement of euthyroid state with propylthiouracil treatment results in shortening of P wave variables. Diastolic function may have a partial effect for the increased Pmax and PWD. Shortening of Pmax and PWD may be a marker for the prevention of AF with the anti-thyroid treatment.
Directory of Open Access Journals (Sweden)
J. Zhu
2016-05-01
Full Text Available The generation of ultrashort electron bunches with ultrasmall bunch arrival-time jitter is of vital importance for laser-plasma wakefield acceleration with external injection. We study the production of 100-MeV electron bunches with bunch durations of subfemtosecond (fs and bunch arrival-time jitters of less than 10 fs, in an S-band photoinjector by using a weak magnetic chicane with a slit collimator. The beam dynamics inside the chicane is simulated by using two codes with different self-force models. The first code separates the self-force into a three-dimensional (3D quasistatic space-charge model and a one-dimensional coherent synchrotron radiation (CSR model, while the other one starts from the first principle with a so-called 3D sub-bunch method. The simulations indicate that the CSR effect dominates the horizontal emittance growth and the 1D CSR model underestimates the final bunch duration and emittance because of the very large transverse-to-longitudinal aspect ratio of the sub-fs bunch. Particularly, the CSR effect is also strongly affected by the vertical bunch size. Due to the coupling between the horizontal and longitudinal phase spaces, the bunch duration at the entrance of the last dipole magnet of the chicane is still significantly longer than that at the exit of the chicane, which considerably mitigates the impact of space charge and CSR effects on the beam quality. Exploiting this effect, a bunch charge of up to 4.8 pC in a sub-fs bunch could be simulated. In addition, we analytically and numerically investigate the impact of different jitter sources on the bunch arrival-time jitter downstream of the chicane, and define the tolerance budgets assuming realistic values of the stability of the linac for different bunch charges and compression schemes.
Improved bag models of P-wave baryons
International Nuclear Information System (INIS)
Wang Fan; Wong Chunwa
1988-01-01
Problems in two previous bag-model calculations of P-wave baryon states are pointed out. The two-body matrix elements used in one of these models, the Myhrer-Wroldsen bag model, have now been revised and corrected by Myhrer, Umino and Wroldsen. We use their corrected matrix elements to construct simple bag models in which baryon masses are stabilized against collapse by using a finite pion size. We find that baryon masses in both ground and excited states can be fitted with the same model parameters. Models with small-bag baryons of the type proposed by Brown and Rho are then obtained. Typical bag radii are 0.5 fm for N, 0.6 fm for Δ and 0.7 fm for P-wave nonstrange baryons. In these models, the mixing angles are still unsatisfactory, while inadequacy in the treatment of center-of-mass motion found in an earlier paper persists. These results are briefly discussed. especially in connection with skyrmion models. (orig.)
Directory of Open Access Journals (Sweden)
S. M. P. McKenna-Lawlor
Full Text Available The arrival times at L1 of eleven travelling shocks associated both with X-ray flaring and with halo CMEs recorded aboard SOHO/LASCO have been considered. Close to the Sun the velocities of these events were estimated using either Type II radio records or CME speeds. Close to the Earth the shocks were detected in the data of various solar wind plasma, interplanetary magnetic field (IMF and energetic particle experiments aboard SOHO, ACE, WIND, INTERBALL-1 and IMP-8. The real-time shock arrival predictions of three numerical models, namely the Shock Time of Arrival Model (STOA, the Interplanetary Shock Propagation Model (ISPM and the Hakamada-Akasofu-Fry Solar Wind Model (HAFv.2 were tested against these observations. This is the first time that energetic protons (tens of keV to a few MeV have been used to complement plasma and IMF data in validating shock propagation models. The models were all generally successful in predicting shock arrivals. STOA provided the smallest values of the "predicted minus measured" arrival times and displayed a typical predictive precision better than about 8 h. The ratio of the calculated standard deviation of the transit times to Earth to the standard deviation of the measurements was estimated for each model (treating interacting events as composite shocks and these ratios turned out to be 0.60, 1.15 and 1.02 for STOA, ISPM and HAFv.2, respectively. If an event in the sample for which the shock velocity was not well known is omitted from consideration, these ratios become 0.36, 0.76 and 0.81, respectively. Larger statistical samples should now be tested. The ratio of the in situ shock velocity and the "Sun to L1" transit velocity (V_{sh} /V_{tr} was in the range of 0.7–0.9 for individual, non-interacting, shock events. HAFv.2 uniquely provided information on those changes in the COBpoint (the moving Connection point on the shock along the IMF to the OBserver which directly influenced energetic
Lourenco, Pedro M.; Kentie, Rosemarie; Schroeder, Julia; Groen, Niko M.; Piersma, Theunis; Bairlein, F.; Hooijmeijer, Jos C.E.W.
2011-01-01
When early breeding is advantageous, migrants underway to the breeding areas may be time stressed. The timing of sequential events such as migration and breeding is expected to be correlated because of a "domino effect", and would be of particular biological importance if timings are repeatable
Jang, S.; Moon, Y.; Na, H.
2012-12-01
We have made a comparison of CME-associated shock arrival times at the earth based on the WSA-ENLIL model with three cone models using 29 halo CMEs from 2001 to 2002. These halo CMEs have cone model parameters from Michalek et al. (2007) as well as their associated interplanetary (IP) shocks. For this study we consider three different cone models (an asymmetric cone model, an ice-cream cone model and an elliptical cone model) to determine CME cone parameters (radial velocity, angular width and source location), which are used for input parameters of the WSA-ENLIL model. The mean absolute error (MAE) of the arrival times for the elliptical cone model is 10 hours, which is about 2 hours smaller than those of the other models. However, this value is still larger than that (8.7 hours) of an empirical model by Kim et al. (2007). We are investigating several possibilities on relatively large errors of the WSA-ENLIL cone model, which may be caused by CME-CME interaction, background solar wind speed, and/or CME density enhancement.
Directory of Open Access Journals (Sweden)
C. M. Scoby
2010-02-01
Full Text Available In this paper we study a new geometry setup for electro-optic sampling (EOS where the electron beam runs parallel to the ⟨110⟩ face of a ZnTe crystal and the probe laser is perpendicular to it and to the beam path. The simple setup is used to encode the time-of-arrival information of a 3.5 MeV<10 pC electron bunch on the spatial profile of the laser pulse. The electric field lines inside the dielectric bend at an angle due to a relatively large (n∼3 index of refraction of the ZnTe crystal. We found theoretically and experimentally that the EOS signal can be maximized with a proper choice of incoming laser polarization angle. We achieved single-shot nondestructive measurement of the relative time of arrival between the pump and the probe beams thus improving the temporal resolution of ultrafast relativistic electron diffraction experiments.
DEFF Research Database (Denmark)
Ingvardson, Jesper Bláfoss; Nielsen, Otto Anker; Raveau, Sebastián
2018-01-01
Waiting time at public transport stops is perceived by passengers to be more onerous than in-vehicle time, hence it strongly influences the attractiveness and use of public transport. Transport models traditionally assume that average waiting times are half the service headway by assuming random...... Copenhagen Area covering metro, suburban, and regional rail stations thereby giving a range of service headways from 2 to 60 min. It was shown that the proposed mixture distribution is superior to other distributions proposed in the literature. This can improve waiting time estimations in public transport...
Entanglement entropy in a holographic p-wave superconductor model
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Li-Fang Li
2015-05-01
Full Text Available In a recent paper, arXiv:1309.4877, a holographic p-wave model has been proposed in an Einstein–Maxwell-complex vector field theory with a negative cosmological constant. The model exhibits rich phase structure depending on the mass and the charge of the vector field. We investigate the behavior of the entanglement entropy of dual field theory in this model. When the above two model parameters change, we observe the second order, first order and zeroth order phase transitions from the behavior of the entanglement entropy at some intermediate temperatures. These imply that the entanglement entropy can indicate not only the occurrence of the phase transition, but also the order of the phase transition. The entanglement entropy is indeed a good probe to phase transition. Furthermore, the “retrograde condensation” which is a sub-dominated phase is also reflected on the entanglement entropy.
Lifshitz effects on holographic p-wave superfluid
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Ya-Bo Wu
2015-02-01
Full Text Available In the probe limit, we numerically build a holographic p-wave superfluid model in the four-dimensional Lifshitz black hole coupled to a Maxwell-complex vector field. We observe the rich phase structure and find that the Lifshitz dynamical exponent z contributes evidently to the effective mass of the matter field and dimension of the gravitational background. Concretely, we obtain that the Cave of Winds appeared only in the five-dimensional anti-de Sitter (AdS spacetime, and the increasing z hinders not only the condensate but also the appearance of the first-order phase transition. Furthermore, our results agree with the Ginzburg–Landau results near the critical temperature. In addition, the previous AdS superfluid model is generalized to the Lifshitz spacetime. Keywords: Gauge/gravity duality, Holographic superconductor, Lifshitz black hole, Maxwell-complex vector field
Entanglement entropy in a holographic p-wave superconductor model
Energy Technology Data Exchange (ETDEWEB)
Li, Li-Fang, E-mail: lilf@itp.ac.cn [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Cai, Rong-Gen, E-mail: cairg@itp.ac.cn [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Li, Li, E-mail: liliphy@itp.ac.cn [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Shen, Chao, E-mail: sc@nssc.ac.cn [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China)
2015-05-15
In a recent paper, (arXiv:1309.4877), a holographic p-wave model has been proposed in an Einstein–Maxwell-complex vector field theory with a negative cosmological constant. The model exhibits rich phase structure depending on the mass and the charge of the vector field. We investigate the behavior of the entanglement entropy of dual field theory in this model. When the above two model parameters change, we observe the second order, first order and zeroth order phase transitions from the behavior of the entanglement entropy at some intermediate temperatures. These imply that the entanglement entropy can indicate not only the occurrence of the phase transition, but also the order of the phase transition. The entanglement entropy is indeed a good probe to phase transition. Furthermore, the “retrograde condensation” which is a sub-dominated phase is also reflected on the entanglement entropy.
Strong CMB constraint on P-wave annihilating dark matter
Directory of Open Access Journals (Sweden)
Haipeng An
2017-10-01
Full Text Available We consider a dark sector consisting of dark matter that is a Dirac fermion and a scalar mediator. This model has been extensively studied in the past. If the scalar couples to the dark matter in a parity conserving manner then dark matter annihilation to two mediators is dominated by the P-wave channel and hence is suppressed at very low momentum. The indirect detection constraint from the anisotropy of the Cosmic Microwave Background is usually thought to be absent in the model because of this suppression. In this letter we show that dark matter annihilation via bound state formation occurs through the S-wave and hence there is a constraint on the parameter space of the model from the Cosmic Microwave Background.
Square vortex lattice in p-wave superconductors
International Nuclear Information System (INIS)
Shiraishi, J.
1999-01-01
Making use of the Ginzburg Landau equation for isotropic p-wave superconductors, we construct the single vortex solution in part analytically. The fourfold symmetry breaking term arising from the tetragonal symmetry distortion of the Fermi surface is crucial, since this term indicates a fourfold distortion of the vortex core somewhat similar to the one found in d-wave superconductors. This fourfold distortion of the vortex core in turn favors the square vortex lattice as observed recently by small angle neutron scattering (SANS) experiment from Sr 2 RuO 4 . We find that the hexagonal vortex lattice at H = H c1 transforms into the square one for H = H cr = 0.26 H c2 . On the other hand the SANS data does not reveal such transition. The square vortex covers everywhere studied by the SANS implying H cr is very close to H c1 . Therefore some improvement in the present model is certainly desirable. (orig.)
Holographic p-wave superfluid in Gauss–Bonnet gravity
International Nuclear Information System (INIS)
Liu, Shancheng; Pan, Qiyuan; Jing, Jiliang
2017-01-01
We construct the holographic p-wave superfluid in Gauss–Bonnet gravity via a Maxwell complex vector field model and investigate the effect of the curvature correction on the superfluid phase transition in the probe limit. We obtain the rich phase structure and find that the higher curvature correction hinders the condensate of the vector field but makes it easier for the appearance of translating point from the second-order transition to the first-order one or for the emergence of the Cave of Winds. Moreover, for the supercurrents versus the superfluid velocity, we observe that our results near the critical temperature are independent of the Gauss–Bonnet parameter and agree well with the Ginzburg–Landau prediction.
Holographic p-wave superfluid in Gauss–Bonnet gravity
Energy Technology Data Exchange (ETDEWEB)
Liu, Shancheng [Department of Physics, Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, Hunan 410081 (China); Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081 (China); Pan, Qiyuan, E-mail: panqiyuan@126.com [Department of Physics, Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, Hunan 410081 (China); Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081 (China); Jing, Jiliang, E-mail: jljing@hunnu.edu.cn [Department of Physics, Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, Hunan 410081 (China); Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081 (China)
2017-02-10
We construct the holographic p-wave superfluid in Gauss–Bonnet gravity via a Maxwell complex vector field model and investigate the effect of the curvature correction on the superfluid phase transition in the probe limit. We obtain the rich phase structure and find that the higher curvature correction hinders the condensate of the vector field but makes it easier for the appearance of translating point from the second-order transition to the first-order one or for the emergence of the Cave of Winds. Moreover, for the supercurrents versus the superfluid velocity, we observe that our results near the critical temperature are independent of the Gauss–Bonnet parameter and agree well with the Ginzburg–Landau prediction.
Czech Academy of Sciences Publication Activity Database
Farra, V.; Pšenčík, Ivan; Jílek, P.
2016-01-01
Roč. 81, č. 2 (2016), C39-C59 ISSN 0016-8033 R&D Projects: GA ČR(CZ) GAP210/11/0117 Institutional support: RVO:67985530 Keywords : anisotropy * P-wave * travel time * moveout Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.391, year: 2016
Energy Technology Data Exchange (ETDEWEB)
Chavez, Marcus Alexander; Willis, Michael David; Covert, Timothy Todd
2014-09-01
The miniaturization of explosive components has driven the need for a corresponding miniaturization of the current diagnostic techniques available to measure the explosive phenomena. Laser interferometry and the use of spectrally coated optical windows have proven to be an essential interrogation technique to acquire particle velocity time history data in one- dimensional gas gun and relatively large-scale explosive experiments. A new diagnostic technique described herein allows for experimental measurement of apparent particle velocity time histories in microscale explosive configurations and can be applied to shocks/non-shocks in inert materials. The diagnostic, Embedded Fiber Optic Sensors (EFOS), has been tested in challenging microscopic experimental configurations that give confidence in the technique's ability to measure the apparent particle velocity time histories of an explosive with pressure outputs in the tenths of kilobars to several kilobars. Embedded Fiber Optic Sensors also allow for several measurements to be acquired in a single experiment because they are microscopic, thus reducing the number of experiments necessary. The future of EFOS technology will focus on further miniaturization, material selection appropriate for the operating pressure regime, and extensive hydrocode and optical analysis to transform apparent particle velocity time histories into true particle velocity time histories as well as the more meaningful pressure time histories.
Sawa, Y.; Yokoyama, T.; Tanaka, Y.; Golubov, Alexandre Avraamovitch
2007-01-01
We study the Josephson effect in chiral p-wave superconductor/diffusive normal metal (DN)/chiral p-wave superconductor (CP/DN/CP) junctions using quasiclassical Green's function formalism with proper boundary conditions. The px+ipy-wave symmetry of superconducting order parameter is chosen which is
Majorana zero modes in the hopping-modulated one-dimensional p-wave superconducting model.
Gao, Yi; Zhou, Tao; Huang, Huaixiang; Huang, Ran
2015-11-20
We investigate the one-dimensional p-wave superconducting model with periodically modulated hopping and show that under time-reversal symmetry, the number of the Majorana zero modes (MZMs) strongly depends on the modulation period. If the modulation period is odd, there can be at most one MZM. However if the period is even, the number of the MZMs can be zero, one and two. In addition, the MZMs will disappear as the chemical potential varies. We derive the condition for the existence of the MZMs and show that the topological properties in this model are dramatically different from the one with periodically modulated potential.
An acoustic wave equation for pure P wave in 2D TTI media
Zhan, Ge; Pestana, Reynam C.; Stoffa, Paul L.
2011-01-01
In this paper, a pure P wave equation for an acoustic 2D TTI media is derived. Compared with conventional TTI coupled equations, the resulting equation is unconditionally stable due to the complete isolation of the SV wave mode. To avoid numerical dispersion and produce high quality images, the rapid expansion method REM is employed for numerical implementation. Synthetic results validate the proposed equation and show that it is a stable algorithm for modeling and reverse time migration RTM in a TTI media for any anisotropic parameter values. © 2011 Society of Exploration Geophysicists.
Elastic pion-nucleon P-wave scattering in soliton models
International Nuclear Information System (INIS)
Holzwarth, G.
1990-01-01
The equivalence of low-energy P-wave πN scattering in soliton models with the well-established Δ-isobar model is shown to hold even if all constraints on redundant collective variables are ignored. This provides strong support for the unusual (time-derivative) form of meson-baryon coupling in such models, and for the expectation that the soliton description of πN-scattering can be reliably extended down to pion threshold energies in a technically simple way. (orig.)
Directory of Open Access Journals (Sweden)
María Inés Zaldívar Ovalle
2014-11-01
Full Text Available In the context of the Relación, by Francisco de Borja y Aragón, this paper will report on the exploratory travels —named Arrival and Conquests— of Spanish encomenderos and soldiers between 1615 and 1621. In this context, the present study highlights some of the difficulties Esquilache faced in the exercise of power as head of the Viceroyalty of Peru. We focus our attention on the specific event named Spanish Government. The reasons discussed this time, are closely related to the battle between soldiers and trustees to obtain personal profit. The latter was a current struggle, dating from the origins of the viceroyalty. However, at the time of the events, such conflicts had worsened due to a complex political and economic situation.
Kakimoto, F.; Tsuchimoto, I.; Enoki, T.; Suga, K.; Nishi, K.
1985-01-01
The arrival time distributions of muons with energies above 1.0GeV and 0.5GeV have been measured in the Akeno air-shower array to study the longitudinal development of muons in air showers with primary energies in the range 10 to the 17th power to 10 to the 18th power ev. The average rise times of muons with energies above 1.0GeV at large core distances are consistent with those expected from very high multiplicity models and, on the contrary, with those expected from the low multiplicity models at small core distances. This implies that the longitudinal development at atmospheric depth smaller than 500 cm square is very fast and that at larger atmospheric depths is rather slow.
Girish, B. S.; Pandey, Deepak; Ramachandran, Hema
2017-08-01
We present a compact, inexpensive multichannel module, APODAS (Avalanche Photodiode Output Data Acquisition System), capable of detecting 0.8 billion photons per second and providing real-time recording on a computer hard-disk, of channel- and time-tagged information of the arrival of upto 0.4 billion photons per second. Built around a Virtex-5 Field Programmable Gate Array (FPGA) unit, APODAS offers a temporal resolution of 5 nanoseconds with zero deadtime in data acquisition, utilising an efficient scheme for time and channel tagging and employing Gigabit ethernet for the transfer of data. Analysis tools have been developed on a Linux platform for multi-fold coincidence studies and time-delayed intensity interferometry. As illustrative examples, the second-order intensity correlation function ( g 2) of light from two commonly used sources in quantum optics —a coherent laser source and a dilute atomic vapour emitting spontaneously, constituting a thermal source— are presented. With easy reconfigurability and with no restriction on the total record length, APODAS can be readily used for studies over various time scales. This is demonstrated by using APODAS to reveal Rabi oscillations on nanosecond time scales in the emission of ultracold atoms, on the one hand, and, on the other hand, to measure the second-order correlation function on the millisecond time scales from tailored light sources. The efficient and versatile performance of APODAS promises its utility in diverse fields, like quantum optics, quantum communication, nuclear physics, astrophysics and biology.
Kareiva, Peter; Morse, Douglass H; Eccleston, Jill
1989-03-01
We compared the patch-choice performances of an ambush predator, the crab spider Misumena vatia (Thomisidae) hunting on common milkweed Asclepias syriaca (Asclepiadaceae) umbles, with two stochastic rule-of-thumb simulation models: one that employed a threshold giving-up time and one that assumed a fixed probability of moving. Adult female Misumena were placed on milkweed plants with three umbels, each with markedly different numbers of flower-seeking prey. Using a variety of visitation regimes derived from observed visitation patterns of insect prey, we found that decreases in among-umbel variance in visitation rates or increases in overall mean visitation rates reduced the "clarity of the optimum" (the difference in the yield obtained as foraging behavior changes), both locally and globally. Yield profiles from both models were extremely flat or jagged over a wide range of prey visitation regimes; thus, differences between optimal and "next-best" strategies differed only modestly over large parts of the "foraging landscape". Although optimal yields from fixed probability simulations were one-third to one-half those obtained from threshold simulations, spiders appear to depart umbels in accordance with the fixed probability rule.
Estimating the Wet-Rock P-Wave Velocity from the Dry-Rock P-Wave Velocity for Pyroclastic Rocks
Kahraman, Sair; Fener, Mustafa; Kilic, Cumhur Ozcan
2017-07-01
Seismic methods are widely used for the geotechnical investigations in volcanic areas or for the determination of the engineering properties of pyroclastic rocks in laboratory. Therefore, developing a relation between the wet- and dry-rock P-wave velocities will be helpful for engineers when evaluating the formation characteristics of pyroclastic rocks. To investigate the predictability of the wet-rock P-wave velocity from the dry-rock P-wave velocity for pyroclastic rocks P-wave velocity measurements were conducted on 27 different pyroclastic rocks. In addition, dry-rock S-wave velocity measurements were conducted. The test results were modeled using Gassmann's and Wood's theories and it was seen that estimates for saturated P-wave velocity from the theories fit well measured data. For samples having values of less and greater than 20%, practical equations were derived for reliably estimating wet-rock P-wave velocity as function of dry-rock P-wave velocity.
Bayır, Pınar Türker; Güray, Ümit; Duyuler, Serkan; Demirkan, Burcu; Kayaalp, Oya; Kanat, Selçuk; Güray, Yeşim
2016-02-01
Polycystic ovary syndrome (PCOS) is associated with increased cardiovascular risk, including ischemic stroke. Prolonged atrial electromechanical interval (EMI) is related to increased atrial fibrillation (AF) risk. The aim of the study is to evaluate atrial EMI and electrocardiographic P-wave indices related to increased AF risk in patients with PCOS. Forty PCOS patients diagnosed on the basis of the Rotterdam criteria and 20 age-matched controls were prospectively included. patients with atrioventricular or intraventricular conduction abnormalities, dysrhythmia or taking antiarrhythmic drugs, atherosclerotic heart disease, cardiomyopathies, valvular lesions, pericardial disease, a history of pulmonary emboli or pulmonary hypertension, and abnormal thyroid function were excluded. Intra and interatrial EMI were measured by tissue Doppler imaging and P-wave dispersion (Pd) was calculated on 12-lead electrocardiography (ECG). The Isovolumetric relaxation time was the interval between the aortic valve closure artifact at the end of the LV outflow envelope and the mitral valve opening artifact at the beginning of the mitral E wave. Patients with PCOS had significantly higher interatrial [38 (24-65) ms vs. 16 (9-19) ms pPCOS group compared with control group [45 (27-60) ms vs. 30 (26-38) ms, pPCOS. PCOS is associated with prolonged inter- and intra-atrial conduction times, which are related to increased AF risk.
Abubakari, A R; Lauder, W; Jones, M C; Kirk, A; Agyemang, C; Bhopal, R S
2009-09-01
To determine the prevalence and distribution of, and trends in, physical inactivity and diabetes in adult West African populations. Systematic review and meta-analysis. Literature searches were conducted using four electronic databases. Journal hand searches and examination of citations of relevant articles were also undertaken. To be included, studies had to be population based, use clearly defined criteria for measuring diabetes and physical inactivity, present data that allowed calculation of the prevalence of diabetes or physical inactivity, and sample adult participants. Studies retrieved were appraised critically. Meta-analysis was performed using the DerSimonian-Laird random effect model. Twenty-one reports were retrieved for diabetes and 15 reports were retrieved for physical in/activity. Most studies (10 for diabetes and six for physical activity) were conducted solely among urban populations. The prevalence of diabetes in West Africa was approximately 4.0% [95% confidence interval (CI) 2.0-9.0] in urban adults and 2.6% (95%CI 1.5-4.4) in rural adults, and was similar in men and women [prevalence ratio (PR) 1.36, 95%CI 0.96-1.92]. Cumulative time trend analyses suggested an increase in the prevalence of diabetes among adults in urban West Africa, from approximately 3.0% (95%CI 1.0-7.0) to 4.0% (95%CI 2.0-9.0) in the past 10 years. The prevalence of inactivity in West Africa was 13% (95%CI 9.0-18.0). An association was found between physical inactivity and being older (> or = 50 years) (PR 1.82, 95%CI 1.36-2.44), female gender (PR 1.62, 95%CI 1.41-1.87) and urban residence (PR 2.04, 95%CI 1.58-2.63). Diabetes and physical inactivity are important public health issues in urban West Africa, with similar prevalences to wealthy industrialized countries. There is an urgent need for policy makers, politicians and health promotion experts to put measures in place to encourage active lifestyles and control diabetes in urban West Africa.
Energy Technology Data Exchange (ETDEWEB)
Brauchler, R.; Doetsch, J.; Dietrich, P.; Sauter, M.
2012-01-10
In this study, hydraulic and seismic tomographic measurements were used to derive a site-specific relationship between the geophysical parameter p-wave velocity and the hydraulic parameters, diffusivity and specific storage. Our field study includes diffusivity tomograms derived from hydraulic travel time tomography, specific storage tomograms, derived from hydraulic attenuation tomography, and p-wave velocity tomograms, derived from seismic tomography. The tomographic inversion was performed in all three cases with the SIRT (Simultaneous Iterative Reconstruction Technique) algorithm, using a ray tracing technique with curved trajectories. The experimental set-up was designed such that the p-wave velocity tomogram overlaps the hydraulic tomograms by half. The experiments were performed at a wellcharacterized sand and gravel aquifer, located in the Leine River valley near Göttingen, Germany. Access to the shallow subsurface was provided by direct-push technology. The high spatial resolution of hydraulic and seismic tomography was exploited to derive representative site-specific relationships between the hydraulic and geophysical parameters, based on the area where geophysical and hydraulic tests were performed. The transformation of the p-wave velocities into hydraulic properties was undertaken using a k-means cluster analysis. Results demonstrate that the combination of hydraulic and geophysical tomographic data is a promising approach to improve hydrogeophysical site characterization.
Increased P-wave dispersion a risk for atrial fibrillation in adolescents with anorexia nervosa.
Ertuğrul, İlker; Akgül, Sinem; Derman, Orhan; Karagöz, Tevfik; Kanbur, Nuray
2016-01-01
Studies have shown that a prolonged P-wave dispersion is a risk factor for the development of atrial fibrillation. The aim of this study was to evaluate P-wave dispersion in adolescents with anorexia nervosa at diagnosis. We evaluated electrocardiographic findings, particularly the P-wave dispersion, at initial assessment in 47 adolescents with anorexia nervosa. Comparison of P-wave dispersion between adolescents with anorexia nervosa and controls showed a statistically significant higher P-wave dispersion in patients with anorexia nervosa (72 ± 16.3 msec) when compared to the control group (43.8 ± 9.5 msec). Percent of body weight lost, lower body mass index, and higher weight loss rate in the patients with anorexia nervosa had no effect on P-wave dispersion. Due to the fact that anorexia nervosa has a high mortality rate we believe that cardiac pathologies such as atrial fibrillation must also be considered in the medical evaluation.
Han, Song; Zhang, Wei; Zhang, Jie
2017-09-01
A fast sweeping method (FSM) determines the first arrival traveltimes of seismic waves by sweeping the velocity model in different directions meanwhile applying a local solver. It is an efficient way to numerically solve Hamilton-Jacobi equations for traveltime calculations. In this study, we develop an improved FSM to calculate the first arrival traveltimes of quasi-P (qP) waves in 2-D tilted transversely isotropic (TTI) media. A local solver utilizes the coupled slowness surface of qP and quasi-SV (qSV) waves to form a quartic equation, and solve it numerically to obtain possible traveltimes of qP-wave. The proposed quartic solver utilizes Fermat's principle to limit the range of the possible solution, then uses the bisection procedure to efficiently determine the real roots. With causality enforced during sweepings, our FSM converges fast in a few iterations, and the exact number depending on the complexity of the velocity model. To improve the accuracy, we employ high-order finite difference schemes and derive the second-order formulae. There is no weak anisotropy assumption, and no approximation is made to the complex slowness surface of qP-wave. In comparison to the traveltimes calculated by a horizontal slowness shooting method, the validity and accuracy of our FSM is demonstrated.
Shiina, Takahiro; Nakajima, Junichi; Matsuzawa, Toru
2018-05-01
We investigate P-wave attenuation, Qp-1, in the Pacific slab beneath northeastern (NE) Japan, adopting for the first time the spectral ratio technique for intraslab earthquakes. When seismograms of two earthquakes are recorded at a station and their ray paths to the station are largely overlapped, station-dependent amplification and structural effects on the overlapped rays can be canceled out from the ratio of the spectral amplitudes of the seismograms. Therefore, adopting the spectral ratio technique for intraslab earthquakes has a great advantage for the precise evaluation of Qp-1 in the slab because the structural effects above the slab, including the high-attenuation mantle wedge, are removed. For estimating the intraslab Qp-1, we determined corner frequency of the intraslab earthquakes using the S-coda wave spectral ratio as the first step. Then, we evaluated the inter-event path attenuation, Δt*, from the ratio of the spectral amplitudes of P waves. The obtained result shows that P-wave attenuation in the Pacific slab marks Qp-1 of 0.0015 (Qp of ∼670) at depths of 50-250 km. This indicates that the P-wave attenuation in the Pacific slab is weaker than that in the mantle wedge. The relatively high-Qp-1 is correlated with the distributions of intraslab earthquakes, suggesting that the P-wave amplitude is more attenuated around active seismicity zones in the slab. Therefore, our observations likely indicate the presence of fractures, hydrous minerals, and dehydrated fluid around seismogenic zones in the slab at intermediate depths.
International Nuclear Information System (INIS)
Badea, A.F.; Brancus, I.M.; Rebel, H.; Haungs, A.; Oehlschlaeger, J.; Zazyan, M.
1999-01-01
The average depth of the maximum X m of the EAS (Extensive Air Shower) development depends on the energy E 0 and the mass of the primary particle, and its dependence from the energy is traditionally expressed by the so-called elongation rate D e defined as change in the average depth of the maximum per decade of E 0 i.e. D e = dX m /dlog 10 E 0 . Invoking the superposition model approximation i.e. assuming that a heavy primary (A) has the same shower elongation rate like a proton, but scaled with energies E 0 /A, one can write X m = X init + D e log 10 (E 0 /A). In 1977 an indirect approach studying D e has been suggested by Linsley. This approach can be applied to shower parameters which do not depend explicitly on the energy of the primary particle, but do depend on the depth of observation X and on the depth X m of shower maximum. The distribution of the EAS muon arrival times, measured at a certain observation level relatively to the arrival time of the shower core reflect the pathlength distribution of the muon travel from locus of production (near the axis) to the observation locus. The basic a priori assumption is that we can associate the mean value or median T of the time distribution to the height of the EAS maximum X m , and that we can express T = f(X,X m ). In order to derive from the energy variation of the arrival time quantities information about elongation rate, some knowledge is required about F i.e. F = - ∂ T/∂X m ) X /∂(T/∂X) X m , in addition to the variations with the depth of observation and the zenith-angle (θ) dependence, respectively. Thus ∂T/∂log 10 E 0 | X = - F·D e ·1/X v ·∂T/∂secθ| E 0 . In a similar way the fluctuations σ(X m ) of X m may be related to the fluctuations σ(T) of T i.e. σ(T) = - σ(X m )· F σ ·1/X v ·∂T/∂secθ| E 0 , with F σ being the corresponding scaling factor for the fluctuation of F. By simulations of the EAS development using the Monte Carlo code CORSIKA the energy and angle
3D elastic full-waveform inversion for OBC data using the P-wave excitation amplitude
Oh, Juwon
2017-08-17
We suggest a fast and efficient 3D elastic full waveform inversion (FWI) algorithm based on the excitation amplitude (maximum energy arrival) of the P-wave in the source wavefield. It evaluates the gradient direction significantly faster than its conventional counterpart. In addition, it removes the long-wavelength artifacts from the gradient, which are often originated from SS correlation process. From these advantages, the excitation approach offers faster convergence not only for the S wave velocity, but also for the entire process of multi-parameter inversion, compared to the conventional FWI. The feasibility of the proposed method is demonstrated through the synthetic Marmousi and a real OBC data from North Sea.
3D elastic full-waveform inversion for OBC data using the P-wave excitation amplitude
Oh, Juwon; Kalita, Mahesh; Alkhalifah, Tariq Ali
2017-01-01
We suggest a fast and efficient 3D elastic full waveform inversion (FWI) algorithm based on the excitation amplitude (maximum energy arrival) of the P-wave in the source wavefield. It evaluates the gradient direction significantly faster than its conventional counterpart. In addition, it removes the long-wavelength artifacts from the gradient, which are often originated from SS correlation process. From these advantages, the excitation approach offers faster convergence not only for the S wave velocity, but also for the entire process of multi-parameter inversion, compared to the conventional FWI. The feasibility of the proposed method is demonstrated through the synthetic Marmousi and a real OBC data from North Sea.
Mitilineos, Stelios A.; Argyreas, Nick D.; Thomopoulos, Stelios C. A.
2009-05-01
A fusion-based localization technique for location-based services in indoor environments is introduced herein, based on ultrasound time-of-arrival measurements from multiple off-the-shelf range estimating sensors which are used in a market-available localization system. In-situ field measurements results indicated that the respective off-the-shelf system was unable to estimate position in most of the cases, while the underlying sensors are of low-quality and yield highly inaccurate range and position estimates. An extensive analysis is performed and a model of the sensor-performance characteristics is established. A low-complexity but accurate sensor fusion and localization technique is then developed, which consists inof evaluating multiple sensor measurements and selecting the one that is considered most-accurate based on the underlying sensor model. Optimality, in the sense of a genie selecting the optimum sensor, is subsequently evaluated and compared to the proposed technique. The experimental results indicate that the proposed fusion method exhibits near-optimal performance and, albeit being theoretically suboptimal, it largely overcomes most flaws of the underlying single-sensor system resulting in a localization system of increased accuracy, robustness and availability.
On the resolution of ECG acquisition systems for the reliable analysis of the P-wave
International Nuclear Information System (INIS)
Censi, Federica; Calcagnini, Giovanni; Mattei, Eugenio; Triventi, Michele; Bartolini, Pietro; Corazza, Ivan; Boriani, Giuseppe
2012-01-01
The analysis of the P-wave on surface ECG is widely used to assess the risk of atrial arrhythmias. In order to provide reliable results, the automatic analysis of the P-wave must be precise and reliable and must take into account technical aspects, one of those being the resolution of the acquisition system. The aim of this note is to investigate the effects of the amplitude resolution of ECG acquisition systems on the P-wave analysis. Starting from ECG recorded by an acquisition system with a less significant bit (LSB) of 31 nV (24 bit on an input range of 524 mVpp), we reproduced an ECG signal as acquired by systems with lower resolution (16, 15, 14, 13 and 12 bit). We found that, when the LSB is of the order of 128 µV (12 bit), a single P-wave is not recognizable on ECG. However, when averaging is applied, a P-wave template can be extracted, apparently suitable for the P-wave analysis. Results obtained in terms of P-wave duration and morphology revealed that the analysis of ECG at lowest resolutions (from 12 to 14 bit, LSB higher than 30 µV) could lead to misleading results. However, the resolution used nowadays in modern electrocardiographs (15 and 16 bit, LSB <10 µV) is sufficient for the reliable analysis of the P-wave. (note)
P-wave dispersion: relationship to left ventricular function in sickle cell anaemia.
Oguanobi, N I; Onwubere, B J; Ike, S O; Anisiuba, B C; Ejim, E C; Ibegbulam, O G
2011-01-01
The prognostic implications of P-wave dispersion in patients with a variety of cardiac disease conditions are increasingly being recognised. The relationship between P-wave dispersion and left ventricular function in sickle cell anaemia is unknown. This study was aimed at evaluating the relationship between P-wave dispersion and left ventricular function in adult Nigerian sickle cell anaemia patients. Between February and August 2007, a total of 62 sickle cell anaemia patients (aged 18-44 years; mean 28.27 ± 5.58) enrolled in the study. These were drawn from patients attending the adult sickle cell clinic of the University of Nigeria Teaching Hospital, Ituku-Ozalla, Enugu. An equal number of age- and gender-matched normal subjects served as controls. All the participants were evaluated with electrocardiography and echocardiography. P-wave dispersion was defined as the difference between the maximum and minimum P-wave duration measured in a 12-lead electrocardiogram. P-wave duration and P-wave dispersion were significantly higher in patients than in controls. Significant correlation was demonstrated between P-wave dispersion and age in the patients (r = 0.387; p = 0.031). A comparison of subsets of sickle cell anaemia patients and controls with comparable haematocrit values (30-35%) showed significantly higher P-wave duration and P-wave dispersion in the patients than in the controls. The P-wave duration in patients and controls, respectively, was 111.10 ± 14.53 ms and 89.14 ± 16.45 ms (t = 3.141; p = 0.006). P-wave dispersion was 64.44 ± 15.86 ms in the patients and 36.43 ± 10.35 ms in the controls (t = 2.752; p = 0.013). Significant negative correlation was found between P-wave dispersion and left ventricular transmitral E/A ratio (r = -0.289; p = 0.023). These findings suggest that P-wave dispersion could be useful in the evaluation of sickle cell patients with left ventricular diastolic dysfunction. Further prospective studies are recommended to evaluate
Anomalous incident-angle and elliptical-polarization rotation of an elastically refracted P-wave
Fa, Lin; Fa, Yuxiao; Zhang, Yandong; Ding, Pengfei; Gong, Jiamin; Li, Guohui; Li, Lijun; Tang, Shaojie; Zhao, Meishan
2015-08-01
We report a newly discovered anomalous incident-angle of an elastically refracted P-wave, arising from a P-wave impinging on an interface between two VTI media with strong anisotropy. This anomalous incident-angle is found to be located in the post-critical incident-angle region corresponding to a refracted P-wave. Invoking Snell’s law for a refracted P-wave provides two distinctive solutions before and after the anomalous incident-angle. For an inhomogeneously refracted and elliptically polarized P-wave at the anomalous incident-angle, its rotational direction experiences an acute variation, from left-hand elliptical to right-hand elliptical polarization. The new findings provide us an enhanced understanding of acoustical-wave scattering and lead potentially to widespread and novel applications.
An efficient hybrid pseudospectral/finite-difference scheme for solving the TTI pure P-wave equation
Zhan, Ge
2013-02-19
The pure P-wave equation for modelling and migration in tilted transversely isotropic (TTI) media has attracted more and more attention in imaging seismic data with anisotropy. The desirable feature is that it is absolutely free of shear-wave artefacts and the consequent alleviation of numerical instabilities generally suffered by some systems of coupled equations. However, due to several forward-backward Fourier transforms in wavefield updating at each time step, the computational cost is significant, and thereby hampers its prevalence. We propose to use a hybrid pseudospectral (PS) and finite-difference (FD) scheme to solve the pure P-wave equation. In the hybrid solution, most of the cost-consuming wavenumber terms in the equation are replaced by inexpensive FD operators, which in turn accelerates the computation and reduces the computational cost. To demonstrate the benefit in cost saving of the new scheme, 2D and 3D reverse-time migration (RTM) examples using the hybrid solution to the pure P-wave equation are carried out, and respective runtimes are listed and compared. Numerical results show that the hybrid strategy demands less computation time and is faster than using the PS method alone. Furthermore, this new TTI RTM algorithm with the hybrid method is computationally less expensive than that with the FD solution to conventional TTI coupled equations. © 2013 Sinopec Geophysical Research Institute.
An efficient hybrid pseudospectral/finite-difference scheme for solving the TTI pure P-wave equation
International Nuclear Information System (INIS)
Zhan, Ge; Pestana, Reynam C; Stoffa, Paul L
2013-01-01
The pure P-wave equation for modelling and migration in tilted transversely isotropic (TTI) media has attracted more and more attention in imaging seismic data with anisotropy. The desirable feature is that it is absolutely free of shear-wave artefacts and the consequent alleviation of numerical instabilities generally suffered by some systems of coupled equations. However, due to several forward–backward Fourier transforms in wavefield updating at each time step, the computational cost is significant, and thereby hampers its prevalence. We propose to use a hybrid pseudospectral (PS) and finite-difference (FD) scheme to solve the pure P-wave equation. In the hybrid solution, most of the cost-consuming wavenumber terms in the equation are replaced by inexpensive FD operators, which in turn accelerates the computation and reduces the computational cost. To demonstrate the benefit in cost saving of the new scheme, 2D and 3D reverse-time migration (RTM) examples using the hybrid solution to the pure P-wave equation are carried out, and respective runtimes are listed and compared. Numerical results show that the hybrid strategy demands less computation time and is faster than using the PS method alone. Furthermore, this new TTI RTM algorithm with the hybrid method is computationally less expensive than that with the FD solution to conventional TTI coupled equations. (paper)
Teleseismic P-wave tomography of the Sunda-Banda Arc subduction zone
Harris, C. W.; Miller, M. S.; Widiyantoro, S.; Supendi, P.; O'Driscoll, L.; Roosmawati, N.; Porritt, R.
2017-12-01
The Sunda-Banda Arc is the site of multiple ongoing tectonic deformation processes and is perhaps the best example of the transition from subduction of oceanic lithosphere to an active arc-continent collision. Investigating the mantle structure that has resulted from the collision of continental Australia, as well as the concurrent phenomena of continental subduction, slab-rollback, lithospheric tearing, and subduction polarity reversal is possible through seismic tomography. While both regional scale and global tomographic models have previously been constructed to study the tectonics this region, here we use 250 seismic stations that span the length of this convergent margin to invert for P-wave velocity perturbations in the upper mantle. We combine data from a temporary deployment of 30 broadband instruments as part of the NSF-funded Banda Arc Project, along with data from permanent broadband stations maintained by the Meteorological, Climatological, and Geophysical Agency of Indonesia (BMKG) to image mantle structure, in particular the subducted Indo-Australian plate. The BMKG dataset spans 2009-2017 and includes >200 broadband seismometers. The Banda Arc array (network YS) adds coverage and resolution to southeastern Indonesia and Timor-Leste, where few permanent seismometers are located but the Australian continent-Banda Arc collision is most advanced. The preliminary model was computed using 50,000 teleseismic P-wave travel-time residuals and 3D finite frequency sensitivity kernels. Results from the inversion of the combined dataset are presented as well as resolution tests to assess the quality of the model. The velocity model shows an arcuate Sunda-Banda slab with morphological changes along strike that correlate with the tectonic collision. The model also features the double-sided Molucca Sea slab and regions of high velocity below the bottom of the transition zone. The resolution added by the targeted USC deployment is clear when comparing models that
Xu, Yang; Luo, Mingzhang; Hei, Chuang; Song, Gangbing
2018-03-01
Owing to its light weight and corrosion resistance, the concrete-filled fiber-reinforced polymer tube (CFFT) structure has a broad application prospect; the concrete compactness is key to the strength of CFFTs. To meet the urgent requirement of compactness monitoring of CFFTs, a quantitative method, which uses an array of four equally spaced piezoceramic patches and an ultrasonic time difference of arrival (TDOA) algorithm, is developed. Since the velocity of the ultrasonic wave propagation in fiber-reinforced polymer (FRP) material is about half of that in concrete material, the compactness condition of CFFT impacts the piezoceramic-induced wave propagation in the CFFT, and differentiates the TDOA for different receivers. An important condition is the half compactness, which can be judged by the Half Compactness Indicator (HCI) based on the TDOAs. To characterize the difference of stress wave propagation durations from the emitter to different receivers, which can be utilized to calculate the concrete infill compactness, the TDOA ratio (TDOAR) is introduced. An innovative algorithm is developed in this paper to estimate the compactness of the CFFT using HCI and TDOAR values. Analytical, numerical, and experimental studies based on a CFFT with seven different states of compactness (empty, 1/10, 1/3, 1/2, 2/3, 9/10, and full) are carried out in this research. Analyses demonstrate that there is a good agreement among the analytical, numerical, and experimental results of the proposed method, which employs a piezoceramic transducer array and the TDOAR for quantitative estimating the compactness of concrete infill in a CFFT.
Directory of Open Access Journals (Sweden)
Unal Guntekin
2009-09-01
Full Text Available Background: Prolonged P wave duration and P wave dispersion (PWD have been associated with an increased risk for atrial fibrillation (AF. Hyperthytodism is a frequent cause of atrial fibrillation (AF. Methods: Forty-two patients with newly diagnosed overt hyperthyroidism and 20 healthy people were enrolled in the study. Transthoracic echocardiography, 12 lead surface ECG and thyroid hormone levels were studied at the time of enrollment and after achievement of euthyroid state with propylthiouracil treatment. Results: Maximum P wave duration (Pmax (97.4±14.6 vs. 84.2±9.5 msec, p<0.001, PWD (42.9±10.7 vs. 31.0±6.2 msec, p<0.001, deceleration (DT (190.7±22.6 vs. 177.0±10.2 msec, p=0.013 and isovolumetric relaxation times (IVRT (90.9±11.2 vs. 79.6±10.5 msec, p<0.001 were significantly higher in hyperthyroid patients compared to control group. Pmax and PWD were significantly correlated with the presence of hyperthyroidism. Pmax (97.4±14.6 to 84.3±8.6 msec, p<0,001 Pmin (54.1±8.6 to 48.1±8.5 msec, p=0.002, PWD (42.9±10.7 to 35.9±8.1 msec, p=0.002 and DT (190.7±22.6 to 185.5±18.3, p=0.036 were significantly decreased after achievement of euthyroid state in patients with hyperthyroidism. Diastolic dyfunction was seen in 5 patients at hyperthroid state but only in one patient at euthyroid state. Conclusions: Hyperthyroidism is associated with prolonged P wave duration and dispersion. Achievement of euthyroid state with propylthiouracil treatment results in shortening of P wave variables. Diastolic function may have a partial effect for the increased Pmax and PWD. Shortening of Pmax and PWD may be a marker for the prevention of AF with the anti-thyroid treatment.
Military jet pilots have higher p-wave dispersions compared to the transport aircraft aircrew
Directory of Open Access Journals (Sweden)
Mustafa Çakar
2016-08-01
Full Text Available Objectives: For the purpose of flight safety military aircrew must be healthy. P-wave dispersion (PWD is the p-wave length difference in an electrocardiographic (ECG examination and represents the risk of developing atrial fibrillation. In the study we aimed at investigating PWD in healthy military aircrew who reported for periodical examinations. Material and Methods: Seventy-five asymptomatic military aircrew were enrolled in the study. All the subjects underwent physical, radiologic and biochemical examinations, and a 12-lead electrocardiography. P-wave dispersions were calculated. Results: The mean age of the study participants was 36.15±8.97 years and the mean p-wave duration was 100.8±12 ms in the whole group. Forty-seven subjects were non-pilot aircrew, and 28 were pilots. Thirteen study subjects were serving in jets, 49 in helicopters, and 13 were transport aircraft pilots. Thirty-six of the helicopter and 11 of the transport aircraft aircrew were non-pilot aircrew. P-wave dispersion was the lowest in the transport aircraft aircrew, and the highest in jet pilots. P-wave dispersions were similar in the pilots and non-pilot aircrew. Twenty-three study subjects were overweight, 19 had thyroiditis, 26 had hepatosteatosis, 4 had hyperbilirubinemia, 2 had hypertension, and 5 had hyperlipidemia. The PWD was significantly associated with thyroid-stimulating hormone (TSH levels. Serum uric acid levels were associated with p-wave durations. Serum TSH levels were the most important predictor of PWD. Conclusions: When TSH levels were associated with PWD, uric acid levels were associated with p-wave duration in the military aircrew. The jet pilots had higher PWDs. These findings reveal that military jet pilots may have a higher risk of developing atrial fibrillation, and PWD should be recorded during periodical examinations.
Temperature effect on microstructure and P-wave propagation in Linyi sandstone
International Nuclear Information System (INIS)
Sun, Hui; Sun, Qiang; Deng, Wenni; Zhang, Weiqiang; Lü, Chao
2017-01-01
Highlights: • Mass loss rate, P-wave velocity change rate and damage factor increase exponentially as temperatures rise. • The damage threshold temperature of sandstone samples is 300 °C and limit temperature is 900 °C. • P-wave velocity change rate of sandstone exhibits excellent linearity with mass loss rate. • Damage factor can be well expressed by mass loss rate. - Abstract: In order to study the effect of high temperature on the sandstone, scanning electron microscope (SEM) experiments and primary wave (P-wave) velocity tests have been carried out on sandstone specimens heated to different temperature. The results showed that: (1) the mass loss rate increases exponentially with the increase of temperature and reaches 2.97% at 900 °C; (2) the P-wave velocity change rate increases exponentially with the increase of temperature while there is some fluctuation before 500 °C; (3) the damage threshold temperature of sandstone samples is 300 °C and the limit temperature is 900 °C; (4) there is a good linear relationship between the mass loss rate and the P-wave velocity change rate, and the correlation coefficient (R) of the fitting line is 0.989; (5) the damage caused by high temperature can be reflected better by the mass loss rate than P-wave velocity change rate. The results obtained in this paper will be good for predicting the properties of sandstone when exposed to high temperature.
Penrod, Bruce; Funderburk, Richard; Dana, Peter
1990-01-01
The results from this survey clearly indicate that the Global Positioning System (GPS) time transfer capability is superior to that of the Loran-C system for absolute timing accuracy, and that even with the most careful calibration of the Loran-C receiver delay and propagation path, inexplicable time of arrival (TOA) biases remain which are larger than the variations across all of the transmitters. Much more data covering years would be needed to show that these biases were stable enough to be removed with a one time site calibration. The synchronization of the transmissions is excellent, all showing low parts in 10(exp 13) offsets versus the United States Naval Observatory (USNO) master clock. With the exception of the Searchlight transmitter, all of the transmissions exhibit timing stabilities over the entire period of less than 300 ns RMS which is at the observed levels of GPS under selective availability (SA). The Loran-C phase instabilities take place over a much greater time interval than those being forced onto the GPS signals under SA, providing for better medium to short term frequency stability. Data show that all but the most distant transmitters offer better than three parts in 10(exp 11) stability at this averaging time. It is in the frequency control area where GPS/Loran-C interoperation will offer some synergistic advantages over GPS alone under SA.
P-Wave Velocity Tomography from Local Earthquakes in Western Mexico
Ochoa-Chávez, Juan A.; Escudero, Christian R.; Núñez-Cornú, Francisco J.; Bandy, William L.
2016-10-01
In western Mexico, the subduction of the Rivera and Cocos plates beneath the North America plate has deformed and fragmented the overriding plate, forming several structural rifts and crustal blocks. To obtain a reliable subsurface image of the continental crust and uppermost mantle in this complex area, we used P-wave arrivals of local earthquakes along with the Fast Marching Method tomography technique. We followed an inversion scheme consisting of (1) the use of a high-quality earthquake catalog and corrected phase picks, (2) the selection of earthquakes using a maximum location error threshold, (3) the estimation of an improved 1-D reference velocity model, and (4) the use of checkerboard testing to determine the optimum configuration of the velocity nodes and inversion parameters. Surprisingly, the tomography results show a very simple δVp distribution that can be described as being controlled by geologic structures formed during two stages of the separation of the Rivera and Cocos plates. The earlier period represents the initial stages of the separation of the Rivera and Cocos plates beneath western Mexico; the later period represents the more advanced stage of rifting where the Rivera and Cocos plates had separated sufficiently to allow melt to accumulate below the Colima Volcanic complex. During the earlier period (14 or 10-1.6 Ma), NE-SW-oriented structures/lineaments (such as the Southern Colima Rift) were formed as the two plates separated. During the second period (1.6 Ma to the present), the deformation is attributed to magma, generated within and above the tear zone between the Rivera and Cocos plates, rising beneath the region of the Colima Volcanic Complex. The rising magma fractured the overlying crust, forming a classic triple-rift junction geometry. This triple-rift system is confined to the mid- to lower crust perhaps indicating that this rifting process is still in an early stage. This fracturing, along with fluid circulation and associated
Testing T-odd, p-even interactions with gamma-rays from neutron p-wave resonances
International Nuclear Information System (INIS)
Barabanov, A.L.
1992-01-01
A new method for the study of time reversal violation is described. It consists of measurements of the forward-backward asymmetry in individual gamma-ray transitions resulting from unpolarized neutron capture in p-wave resonance. An experiment with a 113 Cd target performed at the Dubna pulsed neutron source has been analyzed and a limit on the time reversal odd, parity even interaction extracted. The possibilities of experiments using the powerful pulsed neutron source at Los Alamos are considered. 23 refs.; 2 figs
Li, Zefeng; Peng, Zhigang
2016-06-01
Fault zone head waves (FZHWs) are observed along major strike-slip faults and can provide high-resolution imaging of fault interface properties at seismogenic depth. In this paper, we present a new method to automatically detect FZHWs and pick direct P waves secondary arrivals (DWSAs). The algorithm identifies FZHWs by computing the amplitude ratios between the potential FZHWs and DSWAs. The polarities, polarizations and characteristic periods of FZHWs and DSWAs are then used to refine the picks or evaluate the pick quality. We apply the method to the Parkfield section of the San Andreas Fault where FZHWs have been identified before by manual picks. We compare results from automatically and manually picked arrivals and find general agreement between them. The obtained velocity contrast at Parkfield is generally 5-10 per cent near Middle Mountain while it decreases below 5 per cent near Gold Hill. We also find many FZHWs recorded by the stations within 1 km of the background seismicity (i.e. the Southwest Fracture Zone) that have not been reported before. These FZHWs could be generated within a relatively wide low velocity zone sandwiched between the fast Salinian block on the southwest side and the slow Franciscan Mélange on the northeast side. Station FROB on the southwest (fast) side also recorded a small portion of weak precursory signals before sharp P waves. However, the polarities of weak signals are consistent with the right-lateral strike-slip mechanisms, suggesting that they are unlikely genuine FZHW signals.
Improved modified energy ratio method using a multi-window approach for accurate arrival picking
Lee, Minho; Byun, Joongmoo; Kim, Dowan; Choi, Jihun; Kim, Myungsun
2017-04-01
To identify accurately the location of microseismic events generated during hydraulic fracture stimulation, it is necessary to detect the first break of the P- and S-wave arrival times recorded at multiple receivers. These microseismic data often contain high-amplitude noise, which makes it difficult to identify the P- and S-wave arrival times. The short-term-average to long-term-average (STA/LTA) and modified energy ratio (MER) methods are based on the differences in the energy densities of the noise and signal, and are widely used to identify the P-wave arrival times. The MER method yields more consistent results than the STA/LTA method for data with a low signal-to-noise (S/N) ratio. However, although the MER method shows good results regardless of the delay of the signal wavelet for signals with a high S/N ratio, it may yield poor results if the signal is contaminated by high-amplitude noise and does not have the minimum delay. Here we describe an improved MER (IMER) method, whereby we apply a multiple-windowing approach to overcome the limitations of the MER method. The IMER method contains calculations of an additional MER value using a third window (in addition to the original MER window), as well as the application of a moving average filter to each MER data point to eliminate high-frequency fluctuations in the original MER distributions. The resulting distribution makes it easier to apply thresholding. The proposed IMER method was applied to synthetic and real datasets with various S/N ratios and mixed-delay wavelets. The results show that the IMER method yields a high accuracy rate of around 80% within five sample errors for the synthetic datasets. Likewise, in the case of real datasets, 94.56% of the P-wave picking results obtained by the IMER method had a deviation of less than 0.5 ms (corresponding to 2 samples) from the manual picks.
Energy Technology Data Exchange (ETDEWEB)
Frabboni, Stefano [Department of Physics, University of Modena and Reggio Emilia, Via G. Campi 213/a, 41125 Modena (Italy); CNR-Institute of Nanoscience-S3, Via G. Campi 213/a, 41125 Modena (Italy); Gabrielli, Alessandro [Department of Physics, University of Bologna, Viale B. Pichat 6/2, 40127 Bologna (Italy); INFN, Viale B. Pichat 6/2, 40127 Bologna (Italy); Carlo Gazzadi, Gian [CNR-Institute of Nanoscience-S3, Via G. Campi 213/a, 41125 Modena (Italy); Giorgi, Filippo [Department of Physics, University of Bologna, Viale B. Pichat 6/2, 40127 Bologna (Italy); INFN, Viale B. Pichat 6/2, 40127 Bologna (Italy); Matteucci, Giorgio [Department of Physics, University of Bologna, Viale B. Pichat 6/2, 40127 Bologna (Italy); Pozzi, Giulio, E-mail: giulio.pozzi@unibo.it [Department of Physics, University of Bologna, Viale B. Pichat 6/2, 40127 Bologna (Italy); Cesari, Nicola Semprini; Villa, Mauro; Zoccoli, Antonio [Department of Physics, University of Bologna, Viale B. Pichat 6/2, 40127 Bologna (Italy); INFN, Viale B. Pichat 6/2, 40127 Bologna (Italy)
2012-05-15
The two-slits experiment for single electrons has been carried out by inserting in a conventional transmission electron microscope a thick sample with two nano-slits fabricated by Focused Ion Beam technique and a fast recording system able to measure the electron arrival-time. The detector, designed for experiments in future colliders, is based on a custom CMOS chip equipped with a fast readout chain able to manage up to 10{sup 6} frames per second. In this way, high statistic samples of single electron events can be collected within a time interval short enough to measure the distribution of the electron arrival-times and to observe the build-up of the interference pattern. -- Highlights: Black-Right-Pointing-Pointer We present the first results obtained regarding the two-slits Young-Feynman experiment with single electrons. Black-Right-Pointing-Pointer We use two nano-slits fabricated by Focused Ion Beam technique. Black-Right-Pointing-Pointer We insert in the transmission electron microscope a detector, designed for experiments in future colliders. Black-Right-Pointing-Pointer We record the build-up of high statistic single electron interference patterns. Black-Right-Pointing-Pointer We measure the time distribution of electron arrivals.
Scattering amplitude of ultracold atoms near the p-wave magnetic Feshbach resonance
International Nuclear Information System (INIS)
Zhang Peng; Naidon, Pascal; Ueda, Masahito
2010-01-01
Most of the current theories on the p-wave superfluid in cold atomic gases are based on the effective-range theory for the two-body scattering, where the low-energy p-wave scattering amplitude f 1 (k) is given by f 1 (k)=-1/[ik+1/(Vk 2 )+1/R]. Here k is the incident momentum, V and R are the k-independent scattering volume and effective range, respectively. However, due to the long-range nature of the van der Waals interaction between two colliding ultracold atoms, the p-wave scattering amplitude of the two atoms is not described by the effective-range theory [J. Math. Phys. 4, 54 (1963); Phys. Rev. A 58, 4222 (1998)]. In this paper we provide an explicit calculation for the p-wave scattering of two ultracold atoms near the p-wave magnetic Feshbach resonance. We show that in this case the low-energy p-wave scattering amplitude f 1 (k)=-1/[ik+1/(V eff k 2 )+1/(S eff k)+1/R eff ] where V eff , S eff , and R eff are k-dependent parameters. Based on this result, we identify sufficient conditions for the effective-range theory to be a good approximation of the exact scattering amplitude. Using these conditions we show that the effective-range theory is a good approximation for the p-wave scattering in the ultracold gases of 6 Li and 40 K when the scattering volume is enhanced by the resonance.
Liu, T.; Klemperer, S. L.; Yu, C.; Ning, J.
2017-12-01
In the past decades, P wave receiver functions (PRF) have been routinely used to image the Moho, although it is well known that PRFs are susceptible to contamination from sedimentary multiples. Recently, Virtual Deep Seismic Sounding (VDSS) emerged as a novel method to image the Moho. However, despite successful applications of VDSS on multiple datasets from different areas, how sedimentary basins affect the waveforms of post-critical SsPmp, the Moho reflection phase used in VDSS, is not widely understood. Here, motivated by a dataset collected in the Ordos plateau, which shows distinct effects of sedimentary basins on SsPmp and Pms waveforms, we use synthetic seismograms to study the effects of sedimentary basins on SsPmp and Pms, the phases used in VDSS and PRF respectively. The results show that when the sedimentary thickness is on the same order of magnitude as the dominant wavelength of the incident S wave, SsPmp amplitude decreases significantly with S velocity of the sedimentary layer, whereas increasing sedimentary thickness has little effect in SsPmp amplitude. Our explanation is that the low S velocity layer at the virtual source reduces the incident angle of S wave at the free surface, thus decreases the S-to-P reflection coefficient at the virtual source. In addition, transmission loss associated with the bottom of sedimentary basins also contributes to reducing SsPmp amplitude. This explains not only our observations from the Ordos plateau, but also observations from other areas where post-critical SsPmp is expected to be observable, but instead is too weak to be identified. As for Pms, we observe that increasing sedimentary thickness and decreasing sedimentary velocities both can cause interference between sedimentary multiples and Pms, rendering the Moho depths inferred from Pms arrival times unreliable. The reason is that although Pms amplitude does not vary with sedimentary thickness or velocities, as sedimentary velocities decrease and thickness
Three-dimensional modeling of the Nevada Test Site and vicinity from teleseismic p-wave residuals
International Nuclear Information System (INIS)
Monfort, M.E.; Evans, J.R.
1982-01-01
A teleseismic P-wave travel-time residual study is described which reveals the regional compressional-velocity structure of southern Nevada and neighboring parts of California to a depth of 280 km. During 1980, 98 teleseismic events were recorded at 53 sites. P-wave residuals were calculated relative to a network-wide average residual for each event and are displayed on maps of the stations for each of four event-azimuth quadrants. Fluctuations in these map-patterns of residuals with approach azimuth combined with results of linear, three-dimensional inversions of some 2887 residuals indicate the following characteristics of the velocity structure of the southern Nevada region: (1) a low-velocity body exists in the upper crust 50 km northeast of Beatty, Nevada, near the Miocene Timber Mountain-Silent Canyon caldera complex. Another highly localized low-velocity anomaly occurs near the southwest corner of the Nevada Test Site (NTS). These two anomalies seem to be part of a low-velocity trough extending from Death Valley, California, to about 50 km north of NTS; (2) there is a high-velocity body in the mantle between 81 and 131 km deep centered about 10 km north of the edge of the Timber Mountain caldera; (3) a broad low-velocity body is delineated between 81 and 131 km deep centered about 30 km north of Las Vegas; (4) there is a monotonic increase in travel-time delays from west to east across the region, probably indicating an eastward decrease in velocity, and lower than average velocities in southeastern Nevada below 31 km; and (5) considerable complexity in three-dimensional velocity structure exists in this part of the southern Great Basin. Inversions of teleseismic P-wave travel-time residuals were also performed on data from 12 seismometers in the immediate vicinity of the NTS to make good use of the closer station spacing in that area
Spontaneous Hall effect in a chiral p-wave superconductor
Furusaki, Akira; Matsumoto, Masashige; Sigrist, Manfred
2001-08-01
In a chiral superconductor with broken time-reversal symmetry a ``spontaneous Hall effect'' may be observed. We analyze this phenomenon by taking into account the surface properties of a chiral superconductor. We identify two main contributions to the spontaneous Hall effect. One contribution originates from the Bernoulli (or Lorentz) force due to spontaneous currents running along the surfaces of the superconductor. The other contribution has a topological origin and is related to the intrinsic angular momentum of Cooper pairs. The latter can be described in terms of a Chern-Simons-like term in the low-energy field theory of the superconductor and has some similarities with the quantum Hall effect. The spontaneous Hall effect in a chiral superconductor is, however, nonuniversal. Our analysis is based on three approaches to the problem: a self-consistent solution of the Bogoliubov-de Gennes equation, a generalized Ginzburg-Landau theory, and a hydrodynamic formulation. All three methods consistently lead to the same conclusion that the spontaneous Hall resistance of a two-dimensional superconducting Hall bar is of order h/(ekFλ)2, where kF is the Fermi wave vector and λ is the London penetration depth; the Hall resistance is substantially suppressed from a quantum unit of resistance. Experimental issues in measuring this effect are briefly discussed.
Acoustic VTI wavefield tomography of P-wave surface and VSP data
Li, Vladimir; Tsvankin, Ilya; Guitton, Antoine; Alkhalifah, Tariq Ali
2017-01-01
Transversely isotropic (TI) models have become standard in depth imaging and are often used in waveform inversion. Here, we develop a robust wave-equation-based tomographic algorithm for building acoustic VTI (transversely isotropic with a vertical symmetry axis) velocity models from P-wave surface reflection and vertical seismic profiling (VSP) data. Wavefield extrapolation is performed with an integral operator to avoid generating shear-wave artifacts. Focusing energy in extended images produced by reverse-time migration (RTM) makes it possible to update the zero-dip NMO velocity Vnmo and the anellipiticity parameter η. To constrain the anisotropy coefficient δ and improve the accuracy in Vnmo and η, we employ borehole information by introducing an additional objective-function term designed to fit VSP data. Image-guided smoothing is applied to both data- and image-domain gradients to steer the inversion towards geologically plausible solutions. Testing on the VTI Marmousi model shows that the joint inversion of surface and VSP data helps estimate all three relevant medium parameters.
Acoustic VTI wavefield tomography of P-wave surface and VSP data
Li, Vladimir
2017-08-17
Transversely isotropic (TI) models have become standard in depth imaging and are often used in waveform inversion. Here, we develop a robust wave-equation-based tomographic algorithm for building acoustic VTI (transversely isotropic with a vertical symmetry axis) velocity models from P-wave surface reflection and vertical seismic profiling (VSP) data. Wavefield extrapolation is performed with an integral operator to avoid generating shear-wave artifacts. Focusing energy in extended images produced by reverse-time migration (RTM) makes it possible to update the zero-dip NMO velocity Vnmo and the anellipiticity parameter η. To constrain the anisotropy coefficient δ and improve the accuracy in Vnmo and η, we employ borehole information by introducing an additional objective-function term designed to fit VSP data. Image-guided smoothing is applied to both data- and image-domain gradients to steer the inversion towards geologically plausible solutions. Testing on the VTI Marmousi model shows that the joint inversion of surface and VSP data helps estimate all three relevant medium parameters.
Investigation of Semileptonic {ital B} Meson Decays to {ital p} -Wave Charm Mesons
Energy Technology Data Exchange (ETDEWEB)
Anastassov, A.; Duboscq, J.E.; Fujino, D.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Spencer, M.B.; Sung, M.; Undrus, A.; Wanke, R.; Wolf, A.; Zoeller, M.M. [Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Skubic, P. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P.; Yurko, M. [Purdue University, West Lafayette, Indiana 47907 (United States); Glenn, S.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.P.; Lingel, K.; Marsiske, H.; Perl, M.L.; Savinov, V.; Ugolini, D.; Wang, R.; Zhou, X. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Coan, T.E.; Fadeyev, V.; Korolkov, I.; Maravin, Y.; Narsky, I.; Shelkov, V.; Staeck, J.; Stroynowski, R.; Volobouev, I.; Ye, J. [Southern Methodist University, Dallas, Texas 75275 (United States); Artuso, M.; Efimov, A.; Goldberg, M.; He, D.; Kopp, S.; Moneti, G.C.; Mountain, R.; Schuh, S.; Skwarnicki, T.; Stone, S.; Viehhauser, G.; Xing, X. [Syracuse University, Syracuse, New York 13244 (United States); Bartelt, J.; Csorna, S.E.; Jain, V.; McLean, K.W.; Marka, S. [Vanderbilt University, Nashville, Tennessee 37235 (United States); Godang, R.; Kinoshita, K.; Lai, I.C.; Pomianowski, P.; Schrenk, S. [Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P.; Zhou, G.J. [Wayne State University, Detroit, Michigan 48202 (United States); Barish, B.; Chadha, M.; Chan, S.; Eigen, G.; Miller, J.S.; OGrady, C.; Schmidtler, M.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F. [California Institute of Technology, Pasadena, California 91125 (United States); Bliss, D.W.; Masek, G.; Paar, H.P.; Prell, S.; Sharma, V. and others
1998-05-01
We have studied semileptonic B meson decays with a p -wave charm meson in the final state using 3.29{times}10{sup 6} B{ovr B} events collected with the CLEOII detector at the Cornell Electron-Positron Storage Ring. We find a value for the exclusive semileptonic product branching fraction B(B{sup {minus}}{r_arrow}D{sup 0}{sub 1} {ell}{sup {minus}}{ovr {nu}}{sub {ell}}) B(D{sup 0}{sub 1}{r_arrow}D{sup {asterisk}+} {pi}{sup {minus}})=(0.373{plus_minus}0.085{plus_minus} 0.052{plus_minus}0.024){percent} and an upper limit for B(B{sup {minus}}{r_arrow}D{sup {asterisk}0}{sub 2} {ell}{sup {minus}}{ovr {nu}}{sub {ell}}) B(D{sup {asterisk}0}{sub 2}{r_arrow}D{sup {asterisk}+ }{pi}{sup {minus}}){lt}0.16{percent} (90{percent} C.L.). Furthermore, we present the first measurement of the q{sup 2} spectrum for B{sup {minus}}{r_arrow}D{sup 0}{sub 1}{ell}{sup {minus}} {ovr {nu}}{sub {ell}} . {copyright} {ital 1998} {ital The American Physical Society}
Shifts and widths of p-wave confinement induced resonances in atomic waveguides
International Nuclear Information System (INIS)
Saeidian, Shahpoor; Melezhik, Vladimir S; Schmelcher, Peter
2015-01-01
We develop and analyze a theoretical model to study p-wave Feshbach resonances of identical fermions in atomic waveguides by extending the two-channel model of Lange et al (2009 Phys. Rev. A 79 013622) and Saeidian et al (2012 Phys. Rev. A 86 062713). The experimentally known parameters of Feshbach resonances in free space are used as input of the model. We calculate the shifts and widths of p-wave magnetic Feshbach resonance of 40 K atoms emerging in harmonic waveguides as p-wave confinement induced resonance (CIR). Particularly, we show a possibility to control the width and shift of the p-wave CIR by the trap frequency and the applied magnetic field which could be used in corresponding experiments. Our analysis also demonstrates the importance of the inclusion of the effective range in the computational schemes for the description of the p-wave CIRs contrary to the case of s-wave CIRs where the influence of this term is negligible. (paper)
What Do s- and p-Wave Neutron Average Radiative Widths Reveal
Energy Technology Data Exchange (ETDEWEB)
Mughabghab, S.F.
2010-04-30
A first observation of two resonance-like structures at mass numbers 92 and 112 in the average capture widths of the p-wave neutron resonances relative to the s-wave component is interpreted in terms of a spin-orbit splitting of the 3p single-particle state into P{sub 3/2} and P{sub 1/2} components at the neutron separation energy. A third structure at about A = 124, which is not correlated with the 3p-wave neutron strength function, is possibly due to the Pygmy Dipole Resonance. Five significant results emerge from this investigation: (i) The strength of the spin-orbit potential of the optical-model is determined as 5.7 {+-} 0.5 MeV, (ii) Non-statistical effects dominate the p-wave neutron-capture in the mass region A = 85 - 130, (iii) The background magnitude of the p-wave average capture-width relative to that of the s-wave is determined as 0.50 {+-} 0.05, which is accounted for quantitatively in tenns of the generalized Fermi liquid model of Mughabghab and Dunford, (iv) The p-wave resonances arc partially decoupled from the giant-dipole resonance (GDR), and (v) Gamma-ray transitions, enhanced over the predictions of the GDR, are observed in the {sup 90}Zr - {sup 98}Mo and Sn-Ba regions.
s- and p-wave neutron spectroscopy. Xc. Intermediate structure: 88Sr
International Nuclear Information System (INIS)
Malan, J.G.; Pineo, W.F.E.; Divadeenam, M.; Choi, B.H.; Bilpuch, E.G.; Newson, H.W.
1975-01-01
Neutron total cross section measurements of natural Sr were made from 50-875 keV using a high resolution proton beam and the 7 Li(p,n) reaction as a neutron source. These data were analyzed with the help of an R-Matrix code to extract resonance (energies and other) parameters up to about 850 keV. 2p-1h and particle-vibration doorway interpretation of the s-,p- and d-wave resonances is attempted in terms of the sum rule Σγ/subn/ 2 =γ/subd/ 2 . Predictions based on both of these models agree with the experimental results. As expected the p-wave resonances are stronger than either s- and d-wave structure. Theory accounts for the p-wave strength remarkably well. Possible location of the p-wave s.p. resonance is reproduced with a real potential and its damping due to the imaginary potential is calculated. More fragmentation of the strong p-wave doorways is observed than was expected for a compound nucleus so near 90 Zr, but a larger strength function is observed, apparently due to the p-wave giant resonance. (U.S.)
Relativistic corrections to the form factors of Bc into P-wave orbitally excited charmonium
Zhu, Ruilin
2018-06-01
We investigated the form factors of the Bc meson into P-wave orbitally excited charmonium using the nonrelativistic QCD effective theory. Through the analytic computation, the next-to-leading order relativistic corrections to the form factors were obtained, and the asymptotic expressions were studied in the infinite bottom quark mass limit. Employing the general form factors, we discussed the exclusive decays of the Bc meson into P-wave orbitally excited charmonium and a light meson. We found that the relativistic corrections lead to a large correction for the form factors, which makes the branching ratios of the decay channels B (Bc ± →χcJ (hc) +π± (K±)) larger. These results are useful for the phenomenological analysis of the Bc meson decays into P-wave charmonium, which shall be tested in the LHCb experiments.
Directory of Open Access Journals (Sweden)
F. M. Mele
1995-06-01
Full Text Available A tomographic experiment was performed in the Italian region using local and regional arrivaI times of p and S seismological phases selected from the Italian National Bulletin in the time interval 1984-1991. We deter- mined a 3-D crustal P-wave velocity model using a simultaneous inversion method that iteratively re1ocates the hypocenters and computes the unknown model parameters. A fast two-point ray tracing algorithm was adopted to compute the ray paths and travel times of P", S", P g' Sg phases with good accuracy. Synthetic tests were performed using the "true" hypocenter and station distribution to rough1y evaluate the extension of the areas most densely spanned by the ray paths; the agreement between synthetic and computed models is more satisfactory at Moho depths than in the upper crust. The qua1ity of the model resulting from inversion of real data is examined by the ca1culation of the Spread Function (Toomey and Foulger, 1989. The 3-D crustal P-wave velocity mode1 of the Italian region shows remarkab1e trends at Moho depths: the areas east of the Apennines call for positive adjustments of the initial velocity va1ue, while the west region shows negative ad- justments. The correspondence among the main features of the velocity field, the map of Moho isobaths and the map of the gravity anoma1ies is also outlined.
Dogan, Yuksel; Soylu, Aliye; Eren, Gulay A; Poturoglu, Sule; Dolapcioglu, Can; Sonmez, Kenan; Duman, Habibe; Sevindir, Isa
2011-01-01
In inflammatory bowel disease (IBD) number of thromboembolic events are increased due to hypercoagulupathy and platelet activation. Increases in mean platelet volume (MPV) can lead to platelet activation, this leads to thromboembolic events and can cause acute coronary syndromes. In IBD patients, QT-dispersion and P-wave dispersion are predictors of ventricular arrhythmias and atrial fibrilation; MPV is accepted as a risk factor for acute coronary syndromes, we aimed at evaluating the correlations of these with the duration of disease, its localization and activity. The study group consisted of 69 IBD (Ulcerative colitis n: 54, Crohn's Disease n: 15) patients and the control group included 38 healthy individuals. Disease activity was evaluated both endoscopically and clinically. Patients with existing cardiac conditions, those using QT prolonging medications and having systemic diseases, anemia and electrolyte imbalances were excluded from the study. QT-dispersion, P-wave dispersion and MPV values of both groups were compared with disease activity, its localization, duration of disease and the antibiotics used. The P-wave dispersion values of the study group were significantly higher than those of the control group. Duration of the disease was not associated with QT-dispersion, and MPV levels. QT-dispersion, P-wave dispersion, MPV and platelet count levels were similar between the active and in mild ulcerative colitis patients. QT-dispersion levels were similar between IBD patients and the control group. No difference was observed between P-wave dispersion, QT-dispersion and MPV values; with regards to disease duration, disease activity, and localization in the study group (p>0.05). P-wave dispersion which is accepted as a risk factor for the development of atrial fibirilation was found to be high in our IBD patients. This demonstrates us that the risk of developing atrial fibrillation may be high in patients with IBD. No significant difference was found in the QT
Contribution from S and P waves in pp annihilation at rest
Bendiscioli, G; Fontana, A; Montagna, P; Rotondi, A; Salvini, P; Bertin, A; Bruschi, M; Capponi, M; De Castro, S; Donà, R; Galli, D; Giacobbe, B; Marconi, U; Massa, I; Piccinini, M; Cesari, N S; Spighi, R; Vecchi, S; Vagnoni, V M; Villa, M; Vitale, A; Zoccoli, A; Bianconi, A; Bonomi, G; Lodi-Rizzini, E; Venturelli, L; Zenoni, A; Cicalò, C; De Falco, A; Masoni, A; Puddu, G; Serci, S; Usai, G L; Gorchakov, O E; Prakhov, S N; Rozhdestvensky, A M; Tretyak, V I; Poli, M; Gianotti, P; Guaraldo, C; Lanaro, A; Lucherini, V; Petrascu, C; Kudryavtsev, A E; Balestra, F; Bussa, M P; Busso, L; Cerello, P G; Denisov, O Yu; Ferrero, L; Grasso, A; Maggiora, A; Panzarasa, A; Panzieri, D; Tosello, F; Botta, E; Bressani, Tullio; Calvo, D; Costa, S; D'Isep, D; Feliciello, A; Filippi, A; Marcello, S; Mirfakhraee, N; Agnello, M; Iazzi, F; Minetti, B; Tessaro, S
2001-01-01
The annihilation frequencies of 19 pp annihilation reactions at rest obtained in different target densities are analysed in order to determine the values of the P-wave annihilation percentage at each target density and the average hadronic branching ratios from P- and S-states. Both the assumptions of linear dependence of the annihilation frequencies on the P-wave annihilation percentage of the protonium state and the approach with the enhancement factors of Batty (1989) are considered. Furthermore the cases of incompatible measurements are discussed. (55 refs).
Control and synchronisation in switched arrival systems
Rem, B.; Armbruster, H.D.
2003-01-01
A chaotic model of a production flow called the switched arrival system is extended to include switching times and maintenance. The probability distribution of the chaotic return times is calculated. Scheduling maintenance, loss of production due to switching, and control of the chaotic dynamics is
The effect of instanton-induced interaction on P-wave meson spectra ...
Indian Academy of Sciences (India)
possible to reproduce the observed spectra as the tensor and spin-orbit terms of. OGEP are attractive, and hence naturally triplet states masses will be lower than the corresponding singlet states. Hence, to reproduce the full P-wave spectra it is essential to include the hyperfine interaction term of III to have a consistent. 76.
Tunneling current into the vortex lattice states of s-and p- wave superconductors
International Nuclear Information System (INIS)
Kowalewski, L.; Nogala, M.M.; Thomas, M.; Wojciechowski, R.J.
2000-01-01
The tunneling current between the metallic tip of a scanning microscope and s- and p-wave superconductors in quantizing magnetic field is investigated. The differential conductance is calculated both as a function of bias voltage at the centre of the vortex line and for varying position of the scanning tunneling microscope tip at a stable voltage. (author)
Higher P-Wave Dispersion in Migraine Patients with Higher Number of Attacks
Directory of Open Access Journals (Sweden)
A. Koçer
2012-01-01
Full Text Available Objective and Aim. An imbalance of the sympathetic system may explain many of the clinical manifestations of the migraine. We aimed to evaluate P-waves as a reveal of sympathetic system function in migraine patients and healthy controls. Materials and Methods. Thirty-five episodic type of migraine patients (complained of migraine during 5 years or more, BMI < 30 kg/m2 and 30 controls were included in our study. We measured P-wave durations (minimum, maximum, and dispersion from 12-lead ECG recording during pain-free periods. ECGs were transferred to a personal computer via a scanner and then used for magnification of x400 by Adobe Photoshop software. Results. P-wave durations were found to be similar between migraine patients and controls. Although P WD (P-wave dispersion was similar, the mean value was higher in migraine subjects. P WD was positively correlated with P max (P<0.01. Attacks number per month and male gender were the factors related to the P WD (P<0.01. Conclusions. Many previous studies suggested that increased sympathetic activity may cause an increase in P WD. We found that P WD of migraine patients was higher than controls, and P WD was related to attacks number per month and male gender. Further studies are needed to explain the chronic effects of migraine.
P wave detector with PP rhythm tracking: evaluation in different arrhythmia contexts
International Nuclear Information System (INIS)
Portet, François
2008-01-01
Automatic detection of atrial activity (P waves) in an electrocardiogram (ECG) is a crucial task to diagnose the presence of arrhythmias. The P wave is difficult to detect and most of the approaches in the literature have been evaluated on normal sinus rhythms and rarely considered arrhythmia contexts other than atrial flutter and fibrillation. A novel knowledge-based P wave detector algorithm is presented. It is self-adaptive to the patient and able to deal with certain arrhythmias by tracking the PP rhythm. The detector has been tested on 12 records of the MIT-BIH arrhythmia database containing several ventricular and supra-ventricular arrhythmias. On the overall records, the detector demonstrates Se = 96.60% and Pr = 95.46%; for the normal sinus rhythm, it reaches Se = 97.76% and Pr = 96.80% and, in the case of Mobitz type II, it demonstrates Se = 72.79% and Pr = 99.51%. It also shows good performance for trigeminy and bigeminy, and outperforms some more sophisticated techniques. Although the results emphasize the difficulty of P wave detection in difficult arrhythmias (supra and ventricular tachycardias), it shows that domain knowledge can efficiently support signal processing techniques
Signal-averaged P wave duration and the dimensions of the atria
DEFF Research Database (Denmark)
Dixen, Ulrik; Joens, Christian; Rasmussen, Bo V
2004-01-01
Delay of atrial electrical conduction measured as prolonged signal-averaged P wave duration (SAPWD) could be due to atrial enlargement. Here, we aimed to compare different atrial size parameters obtained from echocardiography with the SAPWD measured with a signal-averaged electrocardiogram (SAECG)....
Dispersion durations of P-wave and QT interval in children treated with a ketogenic diet.
Doksöz, Önder; Güzel, Orkide; Yılmaz, Ünsal; Işgüder, Rana; Çeleğen, Kübra; Meşe, Timur
2014-04-01
Limited data are available on the effects of a ketogenic diet on dispersion duration of P-wave and QT-interval measures in children. We searched for the changes in these measures with serial electrocardiograms in patients treated with a ketogenic diet. Twenty-five drug-resistant patients with epilepsy treated with a ketogenic diet were enrolled in this study. Electrocardiography was performed in all patients before the beginning and at the sixth month after implementation of the ketogenic diet. Heart rate, maximum and minimum P-wave duration, P-wave dispersion, and maximum and minimum corrected QT interval and QT dispersion were manually measured from the 12-lead surface electrocardiogram. Minimum and maximum corrected QT and QT dispersion measurements showed nonsignificant increase at month 6 compared with baseline values. Other previously mentioned electrocardiogram parameters also showed no significant changes. A ketogenic diet of 6 months' duration has no significant effect on electrocardiogram parameters in children. Further studies with larger samples and longer duration of follow-up are needed to clarify the effects of ketogenic diet on P-wave dispersion and corrected QT and QT dispersion. Copyright © 2014 Elsevier Inc. All rights reserved.
P-wave holographic superconductor/insulator phase transitions affected by dark matter sector
International Nuclear Information System (INIS)
Rogatko, Marek; Wysokinski, Karol I.
2016-01-01
The holographic approach to building the p-wave superconductors results in three different models: the Maxwell-vector, the SU(2) Yang-Mills and the helical. In the probe limit approximation, we analytically examine the properties of the first two models in the theory with dark matter sector. It turns out that the effect of dark matter on the Maxwell-vector p-wave model is the same as on the s-wave superconductor studied earlier. For the non-Abelian model we study the phase transitions between p-wave holographic insulator/superconductor and metal/superconductor. Studies of marginally stable modes in the theory under consideration allow us to determine features of p-wave holographic droplet in a constant magnetic field. The dependence of the superconducting transition temperature on the coupling constant α to the dark matter sector is affected by the dark matter density ρ_D. For ρ_D>ρ the transition temperature is a decreasing function of α. The critical chemical potential μ_c for the quantum phase transition between insulator and metal depends on the chemical potential of dark matter μ_D and for μ_D=0 is a decreasing function of α.
Constraining P-wave velocity variations in the upper mantle beneath Southeast Asia
Li, Chang; Hilst, R.D. van der; Toksöz, M. Nafi
2006-01-01
We have produced a P-wave model of the upper mantle beneath Southeast (SE) Asia from reprocessed short period International Seismological Centre (ISC) P and pP data, short period P data of the Annual Bulletin of Chinese Earthquakes (ABCE), and long period PP-P data.We used 3D sensitivity kernels
Constraining spatial variations in P-wave velocity in the upper mantle beneath SE Asia
Li, C.; Hilst, R.D. van der; Toksoz, N.M.
2006-01-01
We have produced a P-wave model of the upper mantle beneath Southeast (SE) Asia from reprocessed short period International Seismological Centre (ISC) P and pP data, short period P data of the Annual Bulletin of Chinese Earthquakes (ABCE), and long period PP-P data.We used 3D sensitivity kernels
P-wave velocity test for assessment of geotechnical properties of ...
Indian Academy of Sciences (India)
Administrator
P-wave velocity test, a non-destructive and easy method to apply in both field ... ditions, has increasingly been conducted to determine the geotechnical properties of rock materials. .... nent elements in the study area and rich in molds of reed ... Kocabas crystals 5–10 μm in size with no internal architecture ... organic matter.
Angle of arrival estimation using spectral interferometry
International Nuclear Information System (INIS)
Barber, Z.W.; Harrington, C.; Thiel, C.W.; Babbitt, W.R.; Krishna Mohan, R.
2010-01-01
We have developed a correlative signal processing concept based on a Mach-Zehnder interferometer and spatial-spectral (S2) materials that enables direct mapping of RF spectral phase as well as power spectral recording. This configuration can be used for precise frequency resolved time delay estimation between signals received by a phased antenna array system that in turn could be utilized to estimate the angle of arrival. We present an analytical theoretical model and a proof-of-principle demonstration of the concept of time difference of arrival estimation with a cryogenically cooled Tm:YAG crystal that operates on microwave signals modulated onto a stabilized optical carrier at 793 nm.
Angle of arrival estimation using spectral interferometry
Energy Technology Data Exchange (ETDEWEB)
Barber, Z.W.; Harrington, C.; Thiel, C.W.; Babbitt, W.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Krishna Mohan, R., E-mail: krishna@spectrum.montana.ed [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States)
2010-09-15
We have developed a correlative signal processing concept based on a Mach-Zehnder interferometer and spatial-spectral (S2) materials that enables direct mapping of RF spectral phase as well as power spectral recording. This configuration can be used for precise frequency resolved time delay estimation between signals received by a phased antenna array system that in turn could be utilized to estimate the angle of arrival. We present an analytical theoretical model and a proof-of-principle demonstration of the concept of time difference of arrival estimation with a cryogenically cooled Tm:YAG crystal that operates on microwave signals modulated onto a stabilized optical carrier at 793 nm.
Lizurek, Grzegorz; Marmureanu, Alexandru; Wiszniowski, Jan
2017-03-01
Bucharest, with a population of approximately 2 million people, has suffered damage from earthquakes in the Vrancea seismic zone, which is located about 170 km from Bucharest, at a depth of 80-200 km. Consequently, an earthquake early warning system (Bucharest Rapid earthquake Early Warning System or BREWS) was constructed to provide some warning about impending shaking from large earthquakes in the Vrancea zone. In order to provide quick estimates of magnitude, seismic moment was first determined from P-waves and then a moment magnitude was determined from the moment. However, this magnitude may not be consistent with previous estimates of magnitude from the Romanian Seismic Network. This paper introduces the algorithm using P-wave spectral levels and compares them with catalog estimates. The testing procedure used waveforms from about 90 events with catalog magnitudes from 3.5 to 5.4. Corrections to the P-wave determined magnitudes according to dominant intermediate depth events mechanism were tested for November 22, 2014, M5.6 and October 17, M6 events. The corrections worked well, but unveiled overestimation of the average magnitude result of about 0.2 magnitude unit in the case of shallow depth event ( H < 60 km). The P-wave spectral approach allows for the relatively fast estimates of magnitude for use in BREWS. The average correction taking into account the most common focal mechanism for radiation pattern coefficient may lead to overestimation of the magnitude for shallow events of about 0.2 magnitude unit. However, in case of events of intermediate depth of M6 the resulting M w is underestimated at about 0.1-0.2. We conclude that our P-wave spectral approach is sufficiently robust for the needs of BREWS for both shallow and intermediate depth events.
Can P wave wavelet analysis predict atrial fibrillation after coronary artery bypass grafting?
Vassilikos, Vassilios; Dakos, George; Chouvarda, Ioanna; Karagounis, Labros; Karvounis, Haralambos; Maglaveras, Nikolaos; Mochlas, Sotirios; Spanos, Panagiotis; Louridas, George
2003-01-01
The purpose of this study was the evaluation of Morlet wavelet analysis of the P wave as a means of predicting the development of atrial fibrillation (AF) in patients who undergo coronary artery bypass grafting (CABG). The P wave was analyzed using the Morlet wavelet in 50 patients who underwent successful CABG. Group A consisted of 17 patients, 12 men and 5 women, of mean age 66.9 +/- 5.9 years, who developed AF postoperatively. Group B consisted of 33 patients, 29 men and 4 women, mean age 62.4 +/- 7.8 years, who remained arrhythmid-free. Using custom-designed software, P wave duration and wavelet parameters expressing the mean and maximum energy of the P wave were calculated from 3-channel digital recordings derived from orthogonal ECG leads (X, Y, and Z), and the vector magnitude (VM) was determined in each of 3 frequency bands (200-160 Hz, 150-100 Hz and 90-50 Hz). Univariate logistic-regression analysis identified a history of hypertension, the mean and maximum energies in all frequency bands along the Z axis, the mean and maximum energies (expressed by the VM) in the 200-160 Hz frequency band, and the mean energy in the 150-100 Hz frequency band along the Y axis as predictors for post-CABG AF. Multivariate analysis identified hypertension, ejection fraction, and the maximum energies in the 90-50 Hz frequency band along the Z and composite-vector axes as independent predictors. This multivariate model had a sensitivity of 91% and a specificity of 65%. We conclude that the Morlet wavelet analysis of the P wave is a very sensitive method of identifying patients who are likely to develop AF after CABG. The occurrence of post-CABG AF can be explained by a different activation pattern along the Z axis.
Xu, Yan; Koper, Keith D.; Sufri, Oner; Zhu, Lupei; Hutko, Alexander R.
2009-04-01
The Mw 7.9 Wenchuan earthquake of 12 May 2008 was the most destructive Chinese earthquake since the 1976 Tangshan event. Tens of thousands of people were killed, hundreds of thousands were injured, and millions were left homeless. Here we infer the detailed rupture process of the Wenchuan earthquake by back-projecting teleseismic P energy from several arrays of seismometers. This technique has only recently become feasible and is potentially faster than traditional finite-fault inversion of teleseismic body waves; therefore, it may reduce the notification time to emergency response agencies. Using the IRIS DMC, we collected 255 vertical component broadband P waves at 30-95° from the epicenter. We found that at periods of 5 s and greater, nearly all of these P waves were coherent enough to be used in a global array. We applied a simple down-sampling heuristic to define a global subarray of 70 stations that reduced the asymmetry and sidelobes of the array response function (ARF). We also considered three regional subarrays of seismometers in Alaska, Australia, and Europe that had apertures less than 30° and P waves that were coherent to periods as short as 1 s. Individual ARFs for these subarrays were skewed toward the subarrays; however, the linear sum of the regional subarray beams at 1 s produced a symmetric ARF, similar to that of the groomed global subarray at 5 s. For both configurations we obtained the same rupture direction, rupture length, and rupture time. We found that the Wenchuan earthquake had three distinct pulses of high beam power at 0, 23, and 57 s after the origin time, with the pulse at 23 s being highest, and that it ruptured unilaterally to the northeast for about 300 km and 110 s, with an average speed of 2.8 km/s. It is possible that similar results can be determined for future large dip-slip earthquakes within 20-30 min of the origin time using relatively sparse global networks of seismometers such as those the USGS uses to locate
Xu, Y.; Koper, K.D.; Sufri, O.; Zhu, L.; Hutko, Alexander R.
2009-01-01
[1] The Mw 7.9 Wenchuan earthquake of 12 May 2008 was the most destructive Chinese earthquake since the 1976 Tangshan event. Tens of thousands of people were killed, hundreds of thousands were injured, and millions were left homeless. Here we infer the detailed rupture process of the Wenchuan earthquake by back-projecting teleseismic P energy from several arrays of seismometers. This technique has only recently become feasible and is potentially faster than traditional finite-fault inversion of teleseismic body waves; therefore, it may reduce the notification time to emergency response agencies. Using the IRIS DMC, we collected 255 vertical component broadband P waves at 30-95?? from the epicenter. We found that at periods of 5 s and greater, nearly all of these P waves were coherent enough to be used in a global array. We applied a simple down-sampling heuristic to define a global subarray of 70 stations that reduced the asymmetry and sidelobes of the array response function (ARF). We also considered three regional subarrays of seismometers in Alaska, Australia, and Europe that had apertures less than 30?? and P waves that were coherent to periods as short as 1 s. Individual ARFs for these subarrays were skewed toward the subarrays; however, the linear sum of the regional subarray beams at 1 s produced a symmetric ARF, similar to that of the groomed global subarray at 5 s. For both configurations we obtained the same rupture direction, rupture length, and rupture time. We found that the Wenchuan earthquake had three distinct pulses of high beam power at 0, 23, and 57 s after the origin time, with the pulse at 23 s being highest, and that it ruptured unilaterally to the northeast for about 300 km and 110 s, with an average speed of 2.8 km/s. It is possible that similar results can be determined for future large dip-slip earthquakes within 20-30 min of the origin time using relatively sparse global networks of seismometers such as those the USGS uses to locate
Directory of Open Access Journals (Sweden)
Rehab F. Khalaf
2011-01-01
Full Text Available We study a queuing system which is equipped with a stand-by server in addition to the main server. The stand-by server provides service to customers only during the period of absence of the main server when either the main server is on a vacation or it is in the state of repairs due to a sudden failure from time to time. The service times, vacation times, and repair times are assumed to follow general arbitrary distributions while the stand-by service times follow exponential distribution. Supplementary variables technique has been used to obtain steady state results in explicit and closed form in terms of the probability generating functions for the number of customers in the queue, the average number of customers, and the average waiting time in the queue while the MathCad software has been used to illustrate the numerical results in this work.
In-medium P-wave quarkonium from the complex lattice QCD potential
International Nuclear Information System (INIS)
Burnier, Yannis; Kaczmarek, Olaf; Rothkopf, Alexander
2016-01-01
We extend our lattice QCD potential based study http://dx.doi.org/10.1007/JHEP12(2015)101 of the in-medium properties of heavy quark bound states to P-wave bottomonium and charmonium. Similar to the behavior found in the S-wave channel their spectra show a characteristic broadening, as well as mass shifts to lower energy with increasing temperature. In contrast to the S-wave states, finite angular momentum leads to the survival of spectral peaks even at temperatures, where the continuum threshold reaches below the bound state remnant mass. We elaborate on the ensuing challenges in defining quarkonium dissolution and present estimates of melting temperatures for the spin averaged χ b and χ c states. As an application to heavy-ion collisions we further estimate the contribution of feed down to S-wave quarkonium through the P-wave states after freezeout.
Covariant trace formalism for heavy meson s-wave to p-wave transitions
International Nuclear Information System (INIS)
Balk, S.; Koerner, J.G.; Thompson, G.; Hussain, F.
1992-06-01
Heavy meson, s- to p-wave, weak transitions are studied in the context of the Heavy Quark Effective Theory using covariant meson wave functions. We use the trace formalism to evaluate the weak transitions. As expected from heavy quark symmetry, the eight transitions between s- and p-wave states are described in terms of only two universal form factors which are given in terms of explicit wave function overlap integrals. We present our results in terms of both invariant and helicity amplitudes. Using our helicity amplitude expressions we discuss rate formulae, helicity structure functions and joint angular decay distributions in the decays B-bar→D**(→(D,D*)+π)+W - (→l - ν l ). The heavy quark symmetry predictions for the one-pion transitions D**→(D,D*)+π are similarly worked out by using trace techniques. (author). 35 refs, 3 figs, 2 tabs
Electron-He+ P-wave elastic scattering and photoabsorption in two-electron systems
International Nuclear Information System (INIS)
Bhatia, A. K.
2006-01-01
In a previous paper [A. K. Bhatia, Phys. Rev. A 69, 032714 (2004)], electron-hydrogen P-wave scattering phase shifts were calculated using the optical potential approach based on the Feshbach projection operator formalism. This method is now extended to the singlet and triplet electron-He + P-wave scattering in the elastic region. Phase shifts are calculated using Hylleraas-type correlation functions with up to 220 terms. Results are rigorous lower bounds to the exact phase shifts, and they are compared to phase shifts obtained from the method of polarized orbitals and close-coupling calculations. The continuum functions calculated here are used to calculate photoabsorption cross sections. Photoionization cross sections of He and photodetachment cross sections of H - are calculated in the elastic region--i.e., leaving He + and H in their respective ground states--and compared with previous calculations. Radiative attachment rates are also calculated
In-medium P-wave quarkonium from the complex lattice QCD potential
Energy Technology Data Exchange (ETDEWEB)
Burnier, Yannis [Institute of Theoretical Physics, EPFL,CH-1015 Lausanne (Switzerland); Kaczmarek, Olaf [Fakultät für Physik, Universität Bielefeld,D-33615 Bielefeld (Germany); Rothkopf, Alexander [Institute for Theoretical Physics, Heidelberg University,Philosophenweg 16, 69120 Heidelberg (Germany)
2016-10-07
We extend our lattice QCD potential based study http://dx.doi.org/10.1007/JHEP12(2015)101 of the in-medium properties of heavy quark bound states to P-wave bottomonium and charmonium. Similar to the behavior found in the S-wave channel their spectra show a characteristic broadening, as well as mass shifts to lower energy with increasing temperature. In contrast to the S-wave states, finite angular momentum leads to the survival of spectral peaks even at temperatures, where the continuum threshold reaches below the bound state remnant mass. We elaborate on the ensuing challenges in defining quarkonium dissolution and present estimates of melting temperatures for the spin averaged χ{sub b} and χ{sub c} states. As an application to heavy-ion collisions we further estimate the contribution of feed down to S-wave quarkonium through the P-wave states after freezeout.
Effects of Single Dose Energy Drink on QT and P-Wave Dispersion
Directory of Open Access Journals (Sweden)
Huseyin Arinc
2013-12-01
Full Text Available INTRODUCTION: Aim of this study is to evaluate the cardiac electrophysiological effects of energy drink (Red Bull on QT and P duration and dispersion on surface electrocardiogram. METHODS: Twenty healthy volunteers older than 17 years of age were included the study. Subjects with a cardiac rhythm except sinus rhythm, history of atrial or ventricular arrhythmia, family history of premature sudden cardiac death, palpitations, T-wave abnormalities, QTc interval greater than 440 milliseconds, or those P-waves and QT intervals unavailable in at least eight ECG leads were excluded. Subjects having insomnia, lactose intolerance, caffeine allergy, recurrent headaches, depression, any psychiatric condition, and history of alcohol or drug abuse, pregnant or lactating women were also excluded from participation. 12 lead ECG was obtained before and after consumption of 250 cc enegry drink. QT and P-wave dispersion was calculated. RESULTS: No significant difference have occurred in heart rate (79 ± 14 vs.81 ±13, p=0.68, systolic pressure (114 ± 14 vs.118 ± 16,p=0.38, diastolic blood pressure (74 ± 12 vs.76 ± 14, p=0.64, QT dispersion (58 ± 12 vs. 57 ± 22, p= 0.785 and P-wave dispersion (37 ± 7 vs. 36 ± 13, p= 0.755 between before and 2 hours after consumption of energy drink. DISCUSSION AND CONCLUSION: Consumption of single dose energy drink doesn't affect QT dispersion and P-wave dispersion, heart rate and blood pressure in healthy adults.
Hyperfine structure of the S- and P-wave states of muonic deuterium
International Nuclear Information System (INIS)
Martynenko, A. P.; Martynenko, G. A.; Sorokin, V. V.; Faustov, R. N.
2016-01-01
Corrections of order α"5 and α"6 to the hyperfine structure of the S- and P-wave states of muonic deuteriumwere calculated on the basis of the quasipotential approach in quantum electrodynamics. Relativistic corrections, vacuum-polarization and deuteron-structure effects, and recoil corrections were taken into account in this calculation. The resulting hyperfine-splitting values can be used in a comparison with experimental data obtained by the CREMA Collaboration.
ESTIMA, Neutron Width Level Spacing, Neutron Strength Function of S- Wave, P-Wave Resonances
International Nuclear Information System (INIS)
Fort, E.
1982-01-01
1 - Description of problem or function: ESTIMA calculates level spacing and neutron strength function of a mixed sequence of s- and p-wave resonances given a set of neutron widths as input parameters. Three algorithms are used, two of which calculate s-wave average parameters and assume that the reduced widths obey a Porter-Thomas distribution truncated by a minimum detection threshold. The third performs a maximum likelihood fit to a truncated chi-squared distribution of any specified number of degrees of freedom, i.e. it can be used for calculating s-wave or p-wave average parameters. Resonances of undeclared angular orbital momentum are divided into groups of probable s-wave and probable p-wave by a simple application of Bayes' Theorem. 2 - Method of solution: Three algorithms are used: i) GAMN method, based on simple moments properties of a Porter-Thomas distribution. ii) Missing Level Estimator, a simplified version of the algorithm used by the program BAYESZ. iii) ESTIMA, a maximum likelihood fit. 3 - Restrictions on the complexity of the problem: A maximum of 400 resonances is allowed in the version available from NEADB, however this restriction can be relaxed by increasing array dimensions
BAYESZ, S-Wave, P-Wave Resonance Level Spacing and Strength Functions
International Nuclear Information System (INIS)
Moore, M.S.
1982-01-01
A - Description of problem or function: BAYESZ calculates average s- and p-wave level spacings, strength functions, and average radiation widths of a mixed sequence of s- and p-wave resonances whose parameters are supplied as input. The code is based on two physical assumptions: 1) The neutron reduced width distribution for each open channel is a chi-squared distribution with one degree of freedom, i.e. Porter-Thomas. 2) The spacing distribution follows the Gaussian Orthogonal Ensemble. This property is used, however, only to fix the s- to p-wave level density ratio as proportional to (2J+1) with a spin cut-off correction. B - Method of solution: The method used is an extension of that described by Moore et al. in reference (1), and is based on the method of moments of a truncated Porter-Thomas distribution. C - Restrictions on the complexity of the problem: Parameters for a maximum of 500 individual resonances can be specified. This restriction can be relaxed by increasing array dimensions
Modeling of pseudoacoustic P-waves in orthorhombic media with a low-rank approximation
Song, Xiaolei
2013-06-04
Wavefield extrapolation in pseudoacoustic orthorhombic anisotropic media suffers from wave-mode coupling and stability limitations in the parameter range. We use the dispersion relation for scalar wave propagation in pseudoacoustic orthorhombic media to model acoustic wavefields. The wavenumber-domain application of the Laplacian operator allows us to propagate the P-waves exclusively, without imposing any conditions on the parameter range of stability. It also allows us to avoid dispersion artifacts commonly associated with evaluating the Laplacian operator in space domain using practical finite-difference stencils. To handle the corresponding space-wavenumber mixed-domain operator, we apply the low-rank approximation approach. Considering the number of parameters necessary to describe orthorhombic anisotropy, the low-rank approach yields space-wavenumber decomposition of the extrapolator operator that is dependent on space location regardless of the parameters, a feature necessary for orthorhombic anisotropy. Numerical experiments that the proposed wavefield extrapolator is accurate and practically free of dispersion. Furthermore, there is no coupling of qSv and qP waves because we use the analytical dispersion solution corresponding to the P-wave.
P-wave pulse analysis to retrieve source and propagation effects in the case of Vrancea earthquakes
International Nuclear Information System (INIS)
Popescu, E.; Popa, M.; Placinta, A.; Grecu, B.; Radulian, M.
2004-01-01
Seismic source parameters and attenuation structure properties are obtained from the first P-wave pulse analysis and empirical Green's function deconvolution. The P pulse characteristics are combined effects of source and path properties. To reproduce the real source and structure parameters it is crucial to apply a method able to distinguish between the different factors affecting the observed seismograms. For example the empirical Green's function deconvolution method (Hartzell, 1978) allows the retrieval of the apparent source time function or source spectrum corrected for path, site and instrumental effects. The apparent source duration is given by the width of the deconvoluted source pulse and is directly related to the source dimension. Once the source time function established, next we can extract the parameters related to path effects. The difference between the pulse recorded at a given station and the source pulse obtained by deconvolution is a measure of the attenuation along the path from focus to the station. On the other hand, the pulse width variations with azimuth depend critically on the fault plane orientation and source directivity. In favourable circumstances (high signal/noise ratio, high resolution and station coverage), the method of analysis proposed in this paper allows the constraint of the rupture plane among the two nodal planes characterizing the fault plane solution, even for small events. P-wave pulse analysis was applied for 25 Vrancea earthquakes recorded between 1999 and 2003 by the Romanian local network to determine source parameters and attenuation properties. Our results outline high-stress drop seismic energy release with relatively simple rupture process for the considered events and strong lateral variation of attenuation of seismic waves across Carpathians Arc. (authors)
Gialafos, Elias J; Dilaveris, Polychronis E; Synetos, Andreas G; Tsolakidis, George F; Papaioannou, Theodoros G; Andrikopoulos, George K; Richter, Dimitris J; Triposkiadis, Filippos; Gialafos, John E
2003-01-01
P wave analysis from the 12-lead ECG is a recent contribution of noninvasive electrocardiology. P wave analysis indices (maximum and minimum P wave duration, P wave dispersion [Pdis = Pmax-Pmin], adjusted P wave dispersion [APdis = Pdis/square root of measured leads], summated P wave duration [Psum], standard deviation of P wave duration [Psd], mean P wave duration [Pmean]) can predict atrial arrhythmias. However, the definitions of all these indices are based on few studies. The aim of this analysis was to define normal values of these indices and the examine possible associations between P wave indices and clinical variables. The study included 1,353 healthy men, 24 +/- 3 years of age, who answered a questionnaire and underwent a detailed physical examination and a digitized 12-lead surface ECG. All P wave indices were analyzed by two independent investigators. Mean values of the ECG indices were: Pmax: 96 +/- 11 ms, Pmin: 57 +/- 9 ms, Pdis: 38 +/- 10 ms, Psum: 924 +/- 96 ms, Psd: 12 +/- 3, APdis: 11 +/- 3 ms, and Pmean: 77 +/- 8 ms. Age was significantly related with Pmax (r = 0.277, P < 0.01), Pmin (r = 0.255, P < 0.001), Psum (r = 0.074, P < 0.01), and Pmean (r = 0.074, P < 0.01). All ECG indices were significantly associated with the R-R interval, and among each other. This study defined normal indices of wave duration and correlations among them. These markers may play an important predictive role in patients with atrial conduction abnormalities.
Fujimoto, Yuhi; Yodogawa, Kenji; Takahashi, Kenta; Tsuboi, Ippei; Hayashi, Hiroshi; Uetake, Shunsuke; Iwasaki, Yu-Ki; Hayashi, Meiso; Miyauchi, Yasushi; Shimizu, Wataru
2017-11-01
Atrial fibrillation (AF) itself creates structural and electrophysiological changes such as atrial enlargement, shortening of refractory period and decrease in conduction velocity, called "atrial remodeling", promoting its persistence. Although the remodeling process is considered to be reversible, it has not been elucidated in detail. The aim of this study was to assess the feasibility of P wave dispersion in the assessment of reverse atrial remodeling following catheter ablation of AF. Consecutive 126 patients (88 males, age 63.0 ± 10.4 years) who underwent catheter ablation for paroxysmal AF were investigated. P wave dispersion was calculated from the 12 lead ECG before, 1 day, 1 month, 3 months and 6 months after the procedure. Left atrial diameter (LAD), left atrial volume index (LAVI), left ventricular ejection fraction (LVEF), transmitral flow velocity waveform (E/A), and tissue Doppler (E/e') on echocardiography, plasma B-type natriuretic peptide (BNP) concentrations, serum creatinine, and estimated glomerular filtration rate (eGFR) were also measured. Of all patients, 103 subjects remained free of AF for 1 year follow-up. In these patients, P wave dispersion was not changed 1 day and 1 month after the procedure. However, it was significantly decreased at 3 and 6 months (50.1 ± 14.8 to 45.4 ± 14.4 ms, p < 0.05, 45.2 ± 9.9 ms, p < 0.05, respectively). Plasma BNP concentrations, LAD and LAVI were decreased (81.1 ± 103.8 to 44.8 ± 38.3 pg/mL, p < 0.05, 38.2 ± 5.7 to 35.9 ± 5.6 mm, p < 0.05, 33.3 ± 14.2 to 29.3 ± 12.3 mL/m 2 , p < 0.05) at 6 months after the procedure. There were no significant changes in LVEF, E/A, E/e', serum creatinine, and eGFR during the follow up period. P wave dispersion was decreased at 3 and 6 months after catheter ablation in patients without recurrence of AF. P wave dispersion is useful for assessment of reverse remodeling after catheter ablation of AF.
Energy Technology Data Exchange (ETDEWEB)
McKenna-Lawlor, S.M.P. [National Univ. of Ireland, Maynooth, Co. Kildare (Ireland). Space Technology Ireland; Fry, C.D. [Exploration Physics International, Inc., Huntsville, AL (United States); Dryer, M. [Exploration Physics International, Inc., Huntsville, AL (United States); NOAA Space Environment Center, Boulder, CO (United States); Heynderickx, D. [D-H Consultancy, Leuven (Belgium); Kecskemety, K. [KFKI Research Institute for Particle and Nuclear Physics, Budapest (Hungary); Kudela, K. [Institute of Experimental Physics, Kosice (Slovakia); Balaz, J. [National Univ. of Ireland, Maynooth, Co. Kildare (Ireland). Space Technology Ireland; Institute of Experimental Physics, Kosice (Slovakia)
2012-07-01
The performance of the Hakamada Akasofu-Fry, version 2 (HAFv.2) numerical model, which provides predictions of solar shock arrival times at Earth, was subjected to a statistical study to investigate those solar/interplanetary circumstances under which the model performed well/poorly during key phases (rise/maximum/decay) of solar cycle 23. In addition to analyzing elements of the overall data set (584 selected events) associated with particular cycle phases, subsets were formed such that those events making up a particular sub-set showed common characteristics. The statistical significance of the results obtained using the various sets/subsets was generally very low and these results were not significant as compared with the hit by chance rate (50 %). This implies a low level of confidence in the predictions of the model with no compelling result encouraging its use. However, the data suggested that the success rates of HAFv.2 were higher when the background solar wind speed at the time of shock initiation was relatively fast. Thus, in scenarios where the background solar wind speed is elevated and the calculated success rate significantly exceeds the rate by chance, the forecasts could provide potential value to the customer. With the composite statistics available for solar cycle 23, the calculated success rate at high solar wind speed, although clearly above 50 %, was indicative rather than conclusive. The RMS error estimated for shock arrival times for every cycle phase and for the composite sample was in each case significantly better than would be expected for a random data set. Also, the parameter ''Probability of Detection, yes'' (PODy) which presents the Proportion of Yes observations that were correctly forecast (i.e. the ratio between the shocks correctly predicted and all the shocks observed), yielded values for the rise/maximum/decay phases of the cycle and using the composite sample of 0.85, 0.64, 0.79 and 0.77, respectively. The
Directory of Open Access Journals (Sweden)
S. M. P. McKenna-Lawlor
2012-02-01
Full Text Available The performance of the Hakamada Akasofu-Fry, version 2 (HAFv.2 numerical model, which provides predictions of solar shock arrival times at Earth, was subjected to a statistical study to investigate those solar/interplanetary circumstances under which the model performed well/poorly during key phases (rise/maximum/decay of solar cycle 23. In addition to analyzing elements of the overall data set (584 selected events associated with particular cycle phases, subsets were formed such that those events making up a particular sub-set showed common characteristics. The statistical significance of the results obtained using the various sets/subsets was generally very low and these results were not significant as compared with the hit by chance rate (50%. This implies a low level of confidence in the predictions of the model with no compelling result encouraging its use. However, the data suggested that the success rates of HAFv.2 were higher when the background solar wind speed at the time of shock initiation was relatively fast. Thus, in scenarios where the background solar wind speed is elevated and the calculated success rate significantly exceeds the rate by chance, the forecasts could provide potential value to the customer. With the composite statistics available for solar cycle 23, the calculated success rate at high solar wind speed, although clearly above 50%, was indicative rather than conclusive. The RMS error estimated for shock arrival times for every cycle phase and for the composite sample was in each case significantly better than would be expected for a random data set. Also, the parameter "Probability of Detection, yes" (PODy which presents the Proportion of Yes observations that were correctly forecast (i.e. the ratio between the shocks correctly predicted and all the shocks observed, yielded values for the rise/maximum/decay phases of the cycle and using the composite sample of 0.85, 0.64, 0.79 and 0.77, respectively. The statistical
Some performance measures for vacation models with a batch Markovian arrival process
Directory of Open Access Journals (Sweden)
Sadrac K. Matendo
1994-01-01
Full Text Available We consider a single server infinite capacity queueing system, where the arrival process is a batch Markovian arrival process (BMAP. Particular BMAPs are the batch Poisson arrival process, the Markovian arrival process (MAP, many batch arrival processes with correlated interarrival times and batch sizes, and superpositions of these processes. We note that the MAP includes phase-type (PH renewal processes and non-renewal processes such as the Markov modulated Poisson process (MMPP.
Jang, Soojeong; Moon, Y.-J.; Lee, Jae-Ok; Na, Hyeonock
2014-09-01
We have made a comparison between coronal mass ejection (CME)-associated shock propagations based on the Wang-Sheeley-Arge (WSA)-ENLIL model using three cone types and in situ observations. For this we use 28 full-halo CMEs, whose cone parameters are determined and their corresponding interplanetary shocks were observed at the Earth, from 2001 to 2002. We consider three different cone types (an asymmetric cone model, an ice cream cone model, and an elliptical cone model) to determine 3-D CME cone parameters (radial velocity, angular width, and source location), which are the input values of the WSA-ENLIL model. The mean absolute error of the CME-associated shock travel times for the WSA-ENLIL model using the ice-cream cone model is 9.9 h, which is about 1 h smaller than those of the other models. We compare the peak values and profiles of solar wind parameters (speed and density) with in situ observations. We find that the root-mean-square errors of solar wind peak speed and density for the ice cream and asymmetric cone model are about 190 km/s and 24/cm3, respectively. We estimate the cross correlations between the models and observations within the time lag of ± 2 days from the shock travel time. The correlation coefficients between the solar wind speeds from the WSA-ENLIL model using three cone types and in situ observations are approximately 0.7, which is larger than those of solar wind density (cc ˜0.6). Our preliminary investigations show that the ice cream cone model seems to be better than the other cone models in terms of the input parameters of the WSA-ENLIL model.
Erdoğan, Sinem B; Tong, Yunjie; Hocke, Lia M; Lindsey, Kimberly P; deB Frederick, Blaise
2016-01-01
Resting state functional connectivity analysis is a widely used method for mapping intrinsic functional organization of the brain. Global signal regression (GSR) is commonly employed for removing systemic global variance from resting state BOLD-fMRI data; however, recent studies have demonstrated that GSR may introduce spurious negative correlations within and between functional networks, calling into question the meaning of anticorrelations reported between some networks. In the present study, we propose that global signal from resting state fMRI is composed primarily of systemic low frequency oscillations (sLFOs) that propagate with cerebral blood circulation throughout the brain. We introduce a novel systemic noise removal strategy for resting state fMRI data, "dynamic global signal regression" (dGSR), which applies a voxel-specific optimal time delay to the global signal prior to regression from voxel-wise time series. We test our hypothesis on two functional systems that are suggested to be intrinsically organized into anticorrelated networks: the default mode network (DMN) and task positive network (TPN). We evaluate the efficacy of dGSR and compare its performance with the conventional "static" global regression (sGSR) method in terms of (i) explaining systemic variance in the data and (ii) enhancing specificity and sensitivity of functional connectivity measures. dGSR increases the amount of BOLD signal variance being modeled and removed relative to sGSR while reducing spurious negative correlations introduced in reference regions by sGSR, and attenuating inflated positive connectivity measures. We conclude that incorporating time delay information for sLFOs into global noise removal strategies is of crucial importance for optimal noise removal from resting state functional connectivity maps.
Relation between the behaviors of P-wave and QT dispersions in elderly patients with heart failure
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Szlejf Cláudia
2002-01-01
Full Text Available OBJECTIVE: To assess the relation between P-wave and QT dispersions in elderly patients with heart failure. METHODS: Forty-seven elderly patients (75.6±6 years with stable heart failure in NYHA functional classes II or III and with ejection fractions of 37±6% underwent body surface mapping to analyze P-wave and QT dispersions. The degree of correlation between P-wave and QT dispersions was assessed, and P-wave dispersion values in patients with QT dispersion greater than and smaller than 100 ms were compared. RESULTS: The mean values of P-wave and QT dispersions were 54±14 ms and 68±27 ms, respectively. The correlation between the 2 variables was R=0.41 (p=0.04. In patients with QT dispersion values > 100 ms, P-wave dispersion was significantly greater than in those with QT dispersion values < 100 ms (58±16 vs 53±12 ms, p=0.04 . CONCLUSION: Our results suggest that, in elderly patients with heart failure, a correlation between the values of P-wave and QT dispersions exists. These findings may have etiopathogenic, pathophysiologic, prognostic, and therapeutic implications, which should be investigated in other studies.
Directory of Open Access Journals (Sweden)
José Miguel Gil-García
2017-09-01
Full Text Available Safety and performance of the turbo-engine in an aircraft is directly affected by the health of its blades. In recent years, several improvements to the sensors have taken place to monitor the blades in a non-intrusive way. The parameters that are usually measured are the distance between the blade tip and the casing, and the passing time at a given point. Simultaneously, several techniques have been developed that allow for the inference—from those parameters and under certain conditions—of the amplitude and frequency of the blade vibration. These measurements are carried out on engines set on a rig, before being installed in an airplane. In order to incorporate these methods during the regular operation of the engine, signal processing that allows for the monitoring of those parameters at all times should be developed. This article introduces an architecture, based on a trifurcated optic sensor and a hardware processor, that fulfills this need. The proposed architecture is scalable and allows several sensors to be simultaneously monitored at different points around a bladed disk. Furthermore, the results obtained by the electronic system will be compared with the results obtained by the validation of the optic sensor.
Knowledge-based scheduling of arrival aircraft
Krzeczowski, K.; Davis, T.; Erzberger, H.; Lev-Ram, I.; Bergh, C.
1995-01-01
A knowledge-based method for scheduling arrival aircraft in the terminal area has been implemented and tested in real-time simulation. The scheduling system automatically sequences, assigns landing times, and assigns runways to arrival aircraft by utilizing continuous updates of aircraft radar data and controller inputs. The scheduling algorithms is driven by a knowledge base which was obtained in over two thousand hours of controller-in-the-loop real-time simulation. The knowledge base contains a series of hierarchical 'rules' and decision logic that examines both performance criteria, such as delay reduction, as well as workload reduction criteria, such as conflict avoidance. The objective of the algorithms is to devise an efficient plan to land the aircraft in a manner acceptable to the air traffic controllers. This paper will describe the scheduling algorithms, give examples of their use, and present data regarding their potential benefits to the air traffic system.
Waveform inversion for orthorhombic anisotropy with P-waves: feasibility & resolution
Kazei, Vladimir; Alkhalifah, Tariq Ali
2018-01-01
Various parameterizations have been suggested to simplify inversions of first arrivals, or P −waves, in orthorhombic anisotropic media, but the number and type of retrievable parameters have not been decisively determined. We show that only six
Chávez-González, Elibet; González-Rodríguez, Emilio; Llanes-Camacho, María Del Carmen; Garí-Llanes, Merlin; García-Nóbrega, Yosvany; García-Sáez, Julieta
2014-01-01
Increased P wave dispersion are identified as a predictor of atrial fibrillation. There are associations between hypertension, P wave dispersion, constitutional and echocardiographic variables. These relationships have been scarcely studied in pediatrics. The aim of this study was to determine the relationship between P wave dispersion, blood pressure, echocardiographic and constitutional variables, and determine the most influential variables on P wave dispersion increases in pediatrics. In the frame of the PROCDEC II project, children from 8 to 11 years old, without known heart conditions were studied. Arterial blood pressure was measured in all the children; a 12-lead surface electrocardiogram and an echocardiogram were done as well. Left ventricular mass index mean values for normotensive (25.91±5.96g/m(2.7)) and hypertensive (30.34±8.48g/m(2.7)) showed significant differences P=.000. When we add prehypertensive and hypertensive there are 50.38% with normal left ventricular mass index and P wave dispersion was increased versus 13.36% of normotensive. Multiple regression demonstrated that the mean blood pressure, duration of A wave of mitral inflow, weight and height have a value of r=0.88 as related to P wave dispersion. P wave dispersion is increased in pre- and hypertensive children compared to normotensive. There are pre- and hypertensive patients with normal left ventricular mass index and increased P wave dispersion. Mean arterial pressure, duration of the A wave of mitral inflow, weight and height are the variables with the highest influence on increased P wave dispersion. Copyright © 2013 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.
Okamoto, Kyosuke; Tsuno, Seiji
2015-10-01
In the earthquake early warning (EEW) system, the epicenter location and magnitude of earthquakes are estimated using the amplitude growth rate of initial P-waves. It has been empirically pointed out that the growth rate becomes smaller as epicentral distance becomes far regardless of the magnitude of earthquakes. So, the epicentral distance can be estimated from the growth rate using this empirical relationship. However, the growth rates calculated from different earthquakes at the same epicentral distance mark considerably different values from each other. Sometimes the growth rates of earthquakes having the same epicentral distance vary by 104 times. Qualitatively, it has been considered that the gap in the growth rates is due to differences in the local heterogeneities that the P-waves propagate through. In this study, we demonstrate theoretically how local heterogeneities in the subsurface disturb the relationship between the growth rate and the epicentral distance. Firstly, we calculate seismic scattered waves in a heterogeneous medium. First-ordered PP, PS, SP, and SS scatterings are considered. The correlation distance of the heterogeneities and fractional fluctuation of elastic parameters control the heterogeneous conditions for the calculation. From the synthesized waves, the growth rate of the initial P-wave is obtained. As a result, we find that a parameter (in this study, correlation distance) controlling heterogeneities plays a key role in the magnitude of the fluctuation of the growth rate. Then, we calculate the regional correlation distances in Japan that can account for the fluctuation of the growth rate of real earthquakes from 1997 to 2011 observed by K-NET and KiK-net. As a result, the spatial distribution of the correlation distance shows locality. So, it is revealed that the growth rates fluctuate according to the locality. When this local fluctuation is taken into account, the accuracy of the estimation of epicentral distances from initial P-waves
Shan, Zhendong; Ling, Daosheng
2018-02-01
This article develops an analytical solution for the transient wave propagation of a cylindrical P-wave line source in a semi-infinite elastic solid with a fluid layer. The analytical solution is presented in a simple closed form in which each term represents a transient physical wave. The Scholte equation is derived, through which the Scholte wave velocity can be determined. The Scholte wave is the wave that propagates along the interface between the fluid and solid. To develop the analytical solution, the wave fields in the fluid and solid are defined, their analytical solutions in the Laplace domain are derived using the boundary and interface conditions, and the solutions are then decomposed into series form according to the power series expansion method. Each item of the series solution has a clear physical meaning and represents a transient wave path. Finally, by applying Cagniard's method and the convolution theorem, the analytical solutions are transformed into the time domain. Numerical examples are provided to illustrate some interesting features in the fluid layer, the interface and the semi-infinite solid. When the P-wave velocity in the fluid is higher than that in the solid, two head waves in the solid, one head wave in the fluid and a Scholte wave at the interface are observed for the cylindrical P-wave line source.
1999-11-01
First Images from FORS2 at VLT KUEYEN on Paranal The first, major astronomical instrument to be installed at the ESO Very Large Telescope (VLT) was FORS1 ( FO cal R educer and S pectrograph) in September 1998. Immediately after being attached to the Cassegrain focus of the first 8.2-m Unit Telescope, ANTU , it produced a series of spectacular images, cf. ESO PR 14/98. Many important observations have since been made with this outstanding facility. Now FORS2 , its powerful twin, has been installed at the second VLT Unit Telescope, KUEYEN . It is the fourth major instrument at the VLT after FORS1 , ISAAC and UVES.. The FORS2 Commissioning Team that is busy installing and testing this large and complex instrument reports that "First Light" was successfully achieved already on October 29, 1999, only two days after FORS2 was first mounted at the Cassegrain focus. Since then, various observation modes have been carefully tested, including normal and high-resolution imaging, echelle and multi-object spectroscopy, as well as fast photometry with millisecond time resolution. A number of fine images were obtained during this work, some of which are made available with the present Press Release. The FORS instruments ESO PR Photo 40a/99 ESO PR Photo 40a/99 [Preview - JPEG: 400 x 345 pix - 203k] [Normal - JPEG: 800 x 689 pix - 563kb] [Full-Res - JPEG: 1280 x 1103 pix - 666kb] Caption to PR Photo 40a/99: This digital photo shows the twin instruments, FORS2 at KUEYEN (in the foreground) and FORS1 at ANTU, seen in the background through the open ventilation doors in the two telescope enclosures. Although they look alike, the two instruments have specific functions, as described in the text. FORS1 and FORS2 are the products of one of the most thorough and advanced technological studies ever made of a ground-based astronomical instrument. They have been specifically designed to investigate the faintest and most remote objects in the universe. They are "multi-mode instruments" that
International Nuclear Information System (INIS)
Kambara, H.; Kashiwaya, S.; Yaguchi, H.; Asano, Y.; Tanaka, Y.; Maeno, Y.
2010-01-01
We report on novel local transport characteristics of naturally formed p-wave superconducting junctions of Sr 2 RuO 4 -Ru eutectic system by using microfabrication technique. We observed quite anomalous voltage-current (differential resistance-current) characteristics for both I//ab and I//c directions, which are not seen in conventional Josephson junctions. The anomalous features suggest the internal degrees of freedom of the superconducting state, possibly due to chiral p-wave domain. The dc current acts as a driving force to move chiral p-wave domain walls and form larger critical current path to cause the anomalous hysteresis.
Stravitz, R Todd; Ilan, Yaron
2017-03-01
The progression of liver disease may be unique among organ system diseases in that progressive fibrosis compromises not only the sufficiency of hepatocyte mass but also impairs blood flow to the liver, resulting in porto-systemic shunting. Although liver biopsy as an assessment of fibrosis has become the key biomarker of and target for new therapies, it is invasive and subject to sampling error, and cannot quantify metabolic function or porto-systemic shunting. Measurement of the hepatic venous pressure gradient accommodates some of the deficiencies of biopsy but requires expertise not widely available and misses minor changes in hepatocellular mass and thereby information about metabolic function. Thus, an unmet need in clinical hepatology remains unfulfilled: a noninvasive biomarker which quantitates both the hepatocellular insufficiency and porto-systemic shunting inherent in progressive hepatic fibrosis. Ideally, such a biomarker should correlate with clinical endpoints including liver-related survival and cirrhotic complications, be performed at the point-of-care, and be affordable and easy to use. This review, an expert opinion, summarizes background and recent data suggesting that metabolic breath tests may now meet these requirements and have a valid place in clinical hepatology to supplant the time-honoured assessment of hepatic fibrosis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Evasion of HSR in S-wave charmonium decaying to P-wave light hadrons
Energy Technology Data Exchange (ETDEWEB)
Li, Gang [Qufu Normal University, Department of Physics, Qufu (China); Liu, Xiao-Hai [Peking University, Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Beijing (China); Zhao, Qiang [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China); CAS, Theoretical Physics Center for Science Facilities, Beijing (China)
2013-09-15
The S-wave charmonium decaying to a P-wave and S-wave light hadron pairs are supposed to be suppressed by the helicity selection rule in the perturbative QCD framework. With an effective Lagrangian method, we show that the intermediate charmed meson loops can provide a possible mechanism for the evasion of the helicity selection rule, and result in sizeable decay branching ratios in some of those channels. The theoretical predictions can be examined by the forthcoming BES-III data in the near future. (orig.)
How a change in the interaction potential affects the p-wave scattering volume
International Nuclear Information System (INIS)
Jamieson, M J; Dalgarno, A
2012-01-01
We derive a simple expression for the change in the s-wave scattering length in terms of zero-energy wavefunctions, we generalize it to obtain an expression for the change in the p-wave scattering volume and we use both expressions to derive the first order differential equations of variable phase theory that are satisfied by the closely related accumulated scattering length and volume. We provide numerical demonstrations for the example of a pair of hydrogen atoms interacting via the X 1 Σ + g molecular state. (fast track communication)
Fermionic spectral functions in backreacting p-wave superconductors at finite temperature
Energy Technology Data Exchange (ETDEWEB)
Giordano, G.L.; Grandi, N.E.; Lugo, A.R. [Instituto de Física de La Plata - CONICET & Departamento de Física - UNLP,C.C. 67, 1900 La Plata (Argentina)
2017-04-14
We investigate the spectral function of fermions in a p-wave superconducting state, at finite both temperature and gravitational coupling, using the AdS/CFT correspondence and extending previous research. We found that, for any coupling below a critical value, the system behaves as its zero temperature limit. By increasing the coupling, the “peak-dip-hump” structure that characterizes the spectral function at fixed momenta disappears. In the region where the normal/superconductor phase transition is first order, the presence of a non-zero order parameter is reflected in the absence of rotational symmetry in the fermionic spectral function at the critical temperature.
Physical modeling and analysis of P-wave attenuation anisotropy in transversely isotropic media
Digital Repository Service at National Institute of Oceanography (India)
Zhu, Y.; Tsvankin, I.; Dewangan, P.; Van Wijk, K.
here H20849Figures 1 and 2aH20850 was to verify the accuracy of the parameter-esti- mation results obtained by Dewangan et al. H208492006H20850. The P-wave source H20849a flat-faced, cylindrical, piezoelectric-contact transducerH20850 was fixed... are assumed to be constant. Receivers 10.8 cm 60 cm Source 70? symmetry axis Figure 1. Physical model of a TI layer with the symmetry axis tilted at 70? H20849from Dewangan et al., 2006H20850. The transmitted wavefield is excited by an ultrasonic contact...
Parity violation effects in the Josephson junction of a p-wave superconductor
International Nuclear Information System (INIS)
Belov, Nikolay A.; Harman, Zoltán
2016-01-01
The phenomenon of the parity violation due to weak interaction may be studied with superconducting systems. Previous research considered the case of conventional superconductors. We here theoretically investigate the parity violation effect in an unconventional p-wave ferromagnetic superconductor, and find that its magnitude can be increased by three orders of magnitude, as compared to results of earlier studies. For potential experimental observations, the superconductor UGe_2 is suggested, together with the description of a possible experimental scheme allowing one to effectively measure and control the phenomenon. Furthermore, we put forward a setup for a further significant enhancement of the signature of parity violation in the system considered.
Effect of Floquet engineering on the p-wave superconductor with second-neighbor couplings
Li, X. P.; Li, C. F.; Wang, L. C.; Zhou, L.
2018-06-01
The influence of the Floquet engineering on a particular one-dimensional p-wave superconductor, Kitaev model, with second-neighbor couplings is investigated in this paper. The effective Hamiltonians in the rotated reference frames have been obtained, and the convergent regions of the approximated Hamiltonian as well as the topological phase diagrams have been analyzed and discussed. We show that by modulating the external driving field amplitude, frequency as well as the second-neighbor hopping amplitude, the rich phase diagrams and transitions between different topological phases can be obtained.
Holographic s-wave and p-wave Josephson junction with backreaction
Energy Technology Data Exchange (ETDEWEB)
Wang, Yong-Qiang; Liu, Shuai [Institute of Theoretical Physics, Lanzhou University,Lanzhou 730000, People’s Republic of (China)
2016-11-22
In this paper, we study the holographic models of s-wave and p-wave Josephoson junction away from probe limit in (3+1)-dimensional spacetime, respectively. With the backreaction of the matter, we obtained the anisotropic black hole solution with the condensation of matter fields. We observe that the critical temperature of Josephoson junction decreases with increasing backreaction. In addition to this, the tunneling current and condenstion of Josephoson junction become smaller as backreaction grows larger, but the relationship between current and phase difference still holds for sine function. Moreover, condenstion of Josephoson junction deceases with increasing width of junction exponentially.
Directory of Open Access Journals (Sweden)
E. Bernal
2002-10-01
Full Text Available Las personas que ocupan una lista de espera sufren a menudo un riesgo adicional derivado del tiempo que pasa hasta que obtienen tratamiento; sin embargo, en otras ocasiones, las personas en lista no tienen necesidad del tratamiento por el que esperan. Ambos argumentos, contrastables con evidencias empíricas, serían suficientes para afirmar que debe llegar la gestión a las listas de espera dejando a un lado políticas más o menos oportunistas. Por políticas oportunistas se entiende mantener la mala información sobre listas o su "maquillaje", utilizar programas de autoconcertación sin más horizonte que llegar a final de año sin lista de más de seis meses, etcétera. El panorama no es del todo oscuro. Algunas iniciativas de gestión (incluso de Política con mayúscula se van abriendo paso y pueden entrar en la agenda de los próximos años. Así, cabe destacar la aplicación de tiempos de atención garantizada o la priorización de las listas en función de criterios explícitos. En todo caso, conviene recordar que, con la excepción de las colas producidas en las salas de espera de los centros de salud y aquéllas que se producen en las puertas de urgencias, el resto de colas del sistema están mediadas por la decisión de un médico. Así que una estrategia ineludible para gestionar las listas de espera consiste en atenuar los problemas derivados de la incertidumbre (o ignorancia con respecto al diagnóstico o al pronóstico de los pacientes.Individuals on the waiting list frequently suffer an additional risk caused by the mean time until they receive treatment; however, other individuals do not need the treatment for which they are waiting. Both arguments, which can be contrasted with empirical evidence, would be sufficient to affirm that waiting list management should be implemented, leaving aside policies that are more of less opportunistic. Opportunistic policies are understood as those providing misinformation on waiting lists or
Chang, Chao-Hsi; Wang, Jian-Xiong; Wu, Xing-Gang
2006-02-01
hadronic production of (cb¯)-quarkonium in S-wave and P-wave states via the mechanism of gluon-gluon fusion are given by the 'complete calculation' approach of the leading order QCD. The contributions from the other mechanisms for P-wave production which are small comparatively are not included. Typical running time: Generally speaking, it depends on which option is used to drive PYTHIA when generating the B events. Typically, for the hadronic production of the S-wave (cb¯)-quarkonium, if the PYTHIA parameter IDWTUP = 1, then it takes about 20 hours on a 1.8 GHz Intel P4-processor machine to generate 1000 events; however if IDWTUP = 3, to generate 10 6 events, it takes only about 40 minutes. For the hadronic production of the P-wave (cb¯)-quarkonium, the necessary time will be almost two times longer than the S-wave quarkonium production.
Data on the electromagnetic pion form factor and p-wave
International Nuclear Information System (INIS)
Dubnicka, S.; Meshcheryakov, V.A.; Milko, J.
1980-01-01
The pion form factor absolute value data (free of the omega meson contribution) are unified with the P-wave isovector ππ phase shift. The resultant real and imaginary parts of the pion form factor are described by means of the Pade approximation. All the data, which involve the pion form factor experimental points from the range of momenta - 0.8432 GeV 2 2 , the pion charge radius, and the P-wave isovector ππ phase shift in the elastic region (including also the generally accepted value of the scattering length) are mutually consistent. The data themselves through the Pade approximation reveal that the aforementioned consistency can be achieved only if the pion form factor left-hand cut from the second Riemann sheet is taken into account. Almost in all of the considered Pade approximations one stable pion form factor zero is found in the space-like region, which might indicate the existence of a diffraction minimum in the differential cross section for elastic e - π scattering as a consequence of the constituent structure of the pion like in the case of the electron elastic scattering on nuclei
Experimental study on p-wave neutron strength functions for light nuclei
International Nuclear Information System (INIS)
Koester, L.; Waschkowski, W.; Meier, J.; Rau, G.; Salehi, M.
1988-01-01
Broad energy distributions in fast neutron beams have been achieved by appropriate filtering of the 236 U fission radiation provided from the RENT converter facility at the FRM research reactor. Transmission measurements in such beams result in average cross sections to which resonance reactions and shape elastic scattering contribute. We used a silicon (124.5 cm) filtered beam with a median energy of 143 keV (width 20 keV) and beams with 1.3 MeV (0.55 to 3 MeV) and 2.1 MeV (1 to 5.5 MeV) obtained through different filter combinations of lead and polyethylene. The relative high energies and the broad spectra made it possible to determine experimentally the contributions of s- and p-wave resonance reactions to the average cross section even for light nuclei. Using the three different beams we determined the average cross sections for the elements in the mass region A = 9 to 65. Analysing the measured cross sections by means of the R matrix formalism provided a complete set of p-wave strength functions and distant level parameters. Moreover, single particle shell effects in the cross sections were observed. In conclusion we obtained information on the 2P and the 3S size resonances and about the validity of the optical model for neutron reactions with light nuclei. (orig.)
Dynamic Response of Underground Circular Lining Tunnels Subjected to Incident P Waves
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Hua Xu
2014-01-01
Full Text Available Dynamic stress concentration in tunnels and underground structures during earthquakes often leads to serious structural damage. A series solution of wave equation for dynamic response of underground circular lining tunnels subjected to incident plane P waves is presented by Fourier-Bessel series expansion method in this paper. The deformation and stress fields of the whole medium of surrounding rock and tunnel were obtained by solving the equations of seismic wave propagation in an elastic half space. Based on the assumption of a large circular arc, a series of solutions for dynamic stress were deduced by using a wave function expansion approach for a circular lining tunnel in an elastic half space rock medium subjected to incident plane P waves. Then, the dynamic response of the circular lining tunnel was obtained by solving a series of algebraic equations after imposing its boundary conditions for displacement and stress of the circular lining tunnel. The effects of different factors on circular lining rock tunnels, including incident frequency, incident angle, buried depth, rock conditions, and lining stiffness, were derived and several application examples are presented. The results may provide a good reference for studies on the dynamic response and aseismic design of tunnels and underground structures.
Speaker Localisation Using Time Difference of Arrival
2008-04-01
School of Electrical and Electronic Engineering of the University of Adelaide. His area of expertise and interest is in Signal Processing including audio ...support of Theatre intelligence capabilities. His recent research interests include: information visualisation , text and data mining, and speech and...by: steering microphone arrays to improve the quality of audio pickup for recording, communication and transcription; enhancing the separation – and
Shturman, Alexander; Bickel, Amitai; Atar, Shaul
2012-08-01
The prognostic value of P-wave duration has been previously evaluated by signal-averaged ECG (SAECG) in patients with various arrhythmias not associated with acute myocardial infarction (AMI). To investigate the clinical correlates and prognostic value of P-wave duration in patients with ST elevation AMI (STEMI). The patients (n = 89) were evaluated on the first, second and third day after admission, as well as one week and one month post-AMI. Survival was determined 2 years after the index STEMI. In comparison with the upper normal range of P-wave duration ( 40% (128.79 +/- 28 msec) (P = 0.001). P-wave duration above 120 msec was significantly correlated with increased complication rate; namely, sustained ventricular tachyarrhythmia (36%), congestive heart failure (41%), atrial fibrillation (11%), recurrent angina (14%), and re-infarction (8%) (P = 0.012, odds ratio 4.267, 95% confidence interval 1.37-13.32). P-wave duration of 126 msec on the day of admission was found to have the highest predictive value for in-hospital complications including LVEF 40% (area under the curve 0.741, P < 0.001). However, we did not find a significant correlation between P-wave duration and mortality after multivariate analysis. P-wave duration as evaluated by SAECG correlates negatively with LVEF post-STEMI, and P-wave duration above 126 msec can be utilized as a non-invasive predictor of in-hospital complications and low LVEF following STEMI.
Tsai, Wei-Chung; Lee, Kun-Tai; Wu, Ming-Tsang; Chu, Chih-Sheng; Lin, Tsung-Hsien; Hsu, Po-Chao; Su, Ho-Ming; Voon, Wen-Chol; Lai, Wen-Ter; Sheu, Sheng-Hsiung
2013-07-01
The 12-lead electrocardiogram (ECG) is a commonly used tool to access left atrial enlargement, which is a marker of left ventricular diastolic dysfunction (LVDD). The aim of this study was to evaluate any association of the P-wave measurements in ECG with left atrial volume (LAV) index and LVDD. This study enrolled 270 patients. In this study, 4 ECG P-wave parameters corrected by heart rate, that is, corrected P-wave maximum duration (PWdurMaxC), corrected P-wave dispersion (PWdisperC), corrected P-wave area (PWareaC) and corrected mean P-wave duration (meanPWdurC), were measured. LAV and left ventricular diastolic parameters were measured from echocardiography. LVDD was defined as a pseudonormal or restrictive mitral inflow pattern. The 4 P-wave parameters were significantly correlated with the LAV index after adjusting for age, sex, diabetes, hypertension, coronary artery disease, body mass index and diastolic blood pressure in multivariate analysis. The standardized β coefficients of PWdurMaxC, PWdisperC, meanPWdurC and PWareaC were 0.338, 0.298, 0.215 and 0.296, respectively. The 4 P-wave parameters were also significantly correlated with LVDD after multivariate logistic regression analysis. The odds ratios (95% confidence intervals) of PWdurMaxC, PWdisperC, meanPWdurC and PWareaC were 1.03 (1.01-1.04), 1.02 (1.04-1.04), 1.04 (1.02-1.07) and 1.01 (1.00-1.02), respectively. This study demonstrated that PWdurMaxC, PWdisperC, meanPWdurC and PWareaC were important determinants of the LAV index and LVDD. Therefore, screening patients by means of the 12-lead ECG may be helpful in identifying a high-risk group of increased LAV index and LVDD.
Overview of contaminant arrival distributions as general evaluation requirements
International Nuclear Information System (INIS)
Anon.
1977-01-01
The environmental consequences of subsurface contamination problems can be completely and effectively evaluated by fulfilling the following five requirements: Determine each present or future outflow boundary of contaminated groundwater; provide the location/arrival-time distributions; provide the location/outflow-quantity distributions; provide these distributions for each individual chemical or biological constituent of environmental importance; and use the arrival distributions to determine the quantity and concentration of each contaminant that will interface with the environment as time passes. The arrival distributions on which these requirements are based provide a reference point for communication among scientists and public decision makers by enabling complicated scientific analyses to be presented as simple summary relationships
Ronen, Simcha
1981-01-01
Examined the effects of a flexible working hours schedule on the arrival and departure times of 162 public sector employees. Results indicated that workers, when scheduling their own workday, deviate only moderately from their preflexitime arrival/departure times; and they tend to develop relatively stable arrival/departure patterns. (Author/RC)
Directory of Open Access Journals (Sweden)
P. De Gori
1997-06-01
Full Text Available High-quality teleseismic data digitally recorded by the National Seismic Network during 1988-1995 have been analysed to tomographically reconstruct the aspherical velocity structure of the upper mantle beneath the Italian region. To improve the quality and the reliability of the tomographic images, both direct (P, PKPdf and secondary (pP,sP,PcP,PP,PKPbc,PKPab travel-time data were used in the inversion. Over 7000 relative residuals were computed with respect to the IASP91 Earth velocity model and inverted using a modified version of the ACH technique. Incorporation of data of secondary phases resulted in a significant improvement of the sampling of the target volume and of the spatial resolution of the heterogeneous zones. The tomographic images show that most of the lateral variations in the velocity field are confined in the first ~250 km of depth. Strong low velocity anomalies are found beneath the Po plain, Tuscany and Eastern Sicily in the depth range between 35 and 85 km. High velocity anomalies dominate the upper mantle beneath the Central-Western Alps, Northern-Central Apennines and Southern Tyrrhenian sea at lithospheric depths between 85 and 150 km. At greater depth, positive anomalies are still observed below the northernmost part of the Apenninic chain and Southern Tyrrhenian sea. Deeper anomalies present in the 3D velocity model computed by inverting only the first arrivals dataset, generally appear less pronounced in the new tomographic reconstructions. We interpret this as the result of the ray sampling improvement on the reduction of the vertical smearing effects.
Doubly excited P-wave resonance states of H− in Debye plasmas
International Nuclear Information System (INIS)
Jiao, L. G.; Ho, Y. K.
2013-01-01
We investigate the doubly excited P-wave resonance states of H − system in Debye plasmas modeled by static screened Coulomb potentials. The screening effects of the plasma environment on resonance parameters (energy and width) are investigated by employing the complex-scaling method with Hylleraas-type wave functions for both the shape and Feshbach resonances associated with the H(N = 2 to 6) thresholds. Under the screening conditions, the H(N) threshold states are no longer l degenerate, and all the H − resonance energy levels are shifted away from their unscreened values toward the continuum. The influence of Debye plasmas on resonance widths has also been investigated. The shape resonance widths are broadened with increasing plasma screening strength, whereas the Feshbach resonance widths would generally decrease. Our results associated with the H(N = 2) and H(N = 3) thresholds are compared with others in the literature
Wong, Jim K; Lobato, Robert L; Pinesett, Andre; Maxwell, Bryan G; Mora-Mangano, Christina T; Perez, Marco V
2014-12-01
To test the hypothesis that including preoperative electrocardiogram (ECG) characteristics with clinical variables significantly improves the new-onset postoperative atrial fibrillation prediction model. Retrospective analysis. Single-center university hospital. Five hundred twenty-six patients, ≥ 18 years of age, who underwent coronary artery bypass grafting, aortic valve replacement, mitral valve replacement/repair, or a combination of valve surgery and coronary artery bypass grafting requiring cardiopulmonary bypass. Retrospective review of medical records. Baseline characteristics and cardiopulmonary bypass times were collected. Digitally-measured timing and voltages from preoperative electrocardiograms were extracted. Postoperative atrial fibrillation was defined as atrial fibrillation requiring therapeutic intervention. Two hundred eight (39.5%) patients developed postoperative atrial fibrillation. Clinical predictors were age, ejection fractionelectrocardiogram variables to the prediction model with only clinical predictors significantly improved the area under the receiver operating characteristic curve, from 0.71 to 0.78 (p<0.01). Overall net reclassification improvement was 0.059 (p = 0.09). Among those who developed postoperative atrial fibrillation, the net reclassification improvement was 0.063 (p = 0.03). Several p-wave characteristics are independently associated with postoperative atrial fibrillation. Addition of these parameters improves the postoperative atrial fibrillation prediction model. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
Anomalous Hall effect in semiconductor quantum wells in proximity to chiral p -wave superconductors
Yang, F.; Yu, T.; Wu, M. W.
2018-05-01
By using the gauge-invariant optical Bloch equation, we perform a microscopic kinetic investigation on the anomalous Hall effect in chiral p -wave superconducting states. Specifically, the intrinsic anomalous Hall conductivity in the absence of the magnetic field is zero as a consequence of Galilean invariance in our description. As for the extrinsic channel, a finite anomalous Hall current is obtained from the impurity scattering with the optically excited normal quasiparticle current even at zero temperature. From our kinetic description, it can be clearly seen that the excited normal quasiparticle current is due to an induced center-of-mass momentum of Cooper pairs through the acceleration driven by ac electric field. For the induced anomalous Hall current, we show that the conventional skew-scattering channel in the linear response makes the dominant contribution in the strong impurity interaction. In this case, our kinetic description as a supplementary viewpoint mostly confirms the results of Kubo formalism in the literature. Nevertheless, in the weak impurity interaction, this skew-scattering channel becomes marginal and we reveal that an induction channel from the Born contribution dominates the anomalous Hall current. This channel, which has long been overlooked in the literature, is due to the particle-hole asymmetry by nonlinear optical excitation. Finally, we study the case in the chiral p -wave superconducting state with a transverse conical magnetization, which breaks the Galilean invariance. In this situation, the intrinsic anomalous Hall conductivity is no longer zero. Comparison of this intrinsic channel with the extrinsic one from impurity scattering is addressed.
Detecting the Elusive P-Wave: A New ECG Lead to Improve the Recording of Atrial Activity.
Kennedy, Alan; Finlay, Dewar D; Guldenring, Daniel; Bond, Raymond R; McLaughlin, James
2016-02-01
In this study, we report on a lead selection method that was developed to detect the optimal bipolar electrode placement for recording of the P-wave. The study population consisted of 117 lead body surface potential maps recorded from 229 healthy subjects. The optimal bipolar lead was developed using the training set (172 subjects) then extracted from the testing dataset (57 subjects) and compared to other lead systems previously reported for improved recording of atrial activity. All leads were assessed in terms of P-wave, QRS, and STT root mean square (RMS). The P/QRST RMS ratio was also investigated to determine the atrioventricular RMS ratio. Finally, the effect of minor electrode misplacements on the P-lead was investigated. The P-lead discovered in this study outperformed all other investigated leads in terms of P-wave RMS. The P-lead showed a significant improvement in median P-wave RMS (93 versus 72 μV, p < 0.001) over the next best lead, Lead II. An improvement in QRS and STT RMS was also observed from the P-lead in comparison to lead II (668 versus 573 μV, p < 0.001) and (327 versus 196 μV, p < 0.001). Although P-wave RMS was reduced by incorrect electrode placement, significant improvement over Lead II was still evident. The P-lead improves P-wave RMS signal strength over all other investigated leads. Also the P-lead does not reduce QRS and STT RMS making it an appropriate choice for atrial arrhythmia monitoring. Given the improvement in signal-to-noise ratio, an improvement in algorithms that rely on P-wave analysis may be achieved.
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Rezzan Deniz Acar
2014-07-01
Full Text Available BACKGROUND: The aim of our study was to investigate the P-wave dispersion from standard electrocardiograms (ECGs in patients with acute myocardial infarction (AMI after cardiac rehabilitation (CR and determine its relation to arterial stiffness. METHODS: This is a prospective study included 33 patients with AMI and successfully re-vascularized by percutaneous coronary intervention (PCI underwent CR. Left ventricular ejection fraction (LVEF was measured by biplane Simpson’s method. Left atrium (LA volume was calculated. The maximum and minimum durations of P-waves (Pmax and Pmin, respectively were detected, and the difference between Pmax and Pmin was defined as P-wave dispersion (Pd = Pmax–Pmin. Aortic elasticity parameters were measured. RESULTS: LVEF was better after CR. The systolic and diastolic blood pressures decreased after CR, these differences were statistically significant. With exercise training, LA volume decreased significantly. Pmax and Pd values were significantly shorter after the CR program. The maximum and minimum P-waves and P-wave dispersion after CR were 97 ± 6 ms, 53 ± 5 ms, and 44 ± 5 ms, respectively. Aortic strain and distensibility increased and aortic stiffness index was decreased significantly. Aortic stiffness index was 0.4 ± 0.2 versus 0.3 ± 0.2, P = 0.001. Aortic stiffness and left atrial volume showed a moderate positive correlation with P-wave dispersion (r = 0.52, P = 0.005; r = 0.64, P = 0.000, respectively. CONCLUSION: This study showed decreased arterial stiffness indexes in AMI patient’s participated CR, with a significant relationship between the electromechanical properties of the LA that may raise a question of the preventive effect of CR from atrial fibrillation and stroke in patients with acute myocardial infarction. Keywords: Cardiac Rehabilitation, P-Wave Dispersion, Aortic Stiffness, Acute Myocardial Infarction
Order of arrival affects competition in two reef fishes.
Geange, Shane W; Stier, Adrian C
2009-10-01
Many communities experience repeated periods of colonization due to seasonally regenerating habitats or pulsed arrival of young-of-year. When an individual's persistence in a community depends upon the strength of competitive interactions, changes in the timing of arrival relative to the arrival of a competitor can modify competitive strength and, ultimately, establishment in the community. We investigated whether the strength of intracohort competitive interactions between recent settlers of the reef fishes Thalassoma hardwicke and T. quinquevittatum are dependent on the sequence and temporal separation of their arrival into communities. To achieve this, we manipulated the sequence and timing of arrival of each species onto experimental patch reefs by simulating settlement pulses and monitoring survival and aggressive interactions. Both species survived best in the absence of competitors, but when competitors were present, they did best when they arrived at the same time. Survival declined as each species entered the community progressively later than its competitor and as aggression by its competitor increased. Intraspecific effects of resident T. hardwicke were similar to interspecific effects. This study shows that the strength of competition depends not only on the identity of competitors, but also on the sequence and timing of their interactions, suggesting that when examining interaction strengths, it is important to identify temporal variability in the direction and magnitude of their effects. Furthermore, our findings provide empirical evidence for the importance of competitive lotteries in the maintenance of species diversity in demographically open marine systems.
Akdag, S; Cim, N; Yildizhan, R; Akyol, A; Ozturk, F; Babat, N
2015-09-01
Polycystic ovary syndrome (PCOS) is a prevalent disease with many potential long-term cardiovascular risks. P-wave dispersion (Pdis) and QT dispersion (QTdis) have been shown to be noninvasive electrocardiographic predictors for development of cardiac arrhythmias. In this study we aimed to search Pdis and QTdis parameters in patients with PCOS. The study included 82 patients with PCOS and 74 age- and sex-matched healthy controls. Baseline 12-lead electrocardiographic and transthoracic echocardiographic measurements were evaluated. P-wave maximum duration (Pmax), P-wave minimum duration (Pmin), Pdis, QT interval, heart rate-corrected QT dispersion and QTdis were calculated by two cardiologists. Patients wirh PCOS had significantly higher QT dispersion (49.5 ± 14.1 vs. 37.9 ± 12.6 ms, p PCOS patients.
Bhatia, A. K.
2012-01-01
The P-wave hybrid theory of electron-hydrogen elastic scattering [Phys. Rev. A 85, 052708 (2012)] is applied to the P-wave scattering from He ion. In this method, both short-range and long-range correlations are included in the Schroedinger equation at the same time, by using a combination of a modified method of polarized orbitals and the optical potential formalism. The short-correlation functions are of Hylleraas type. It is found that the phase shifts are not significantly affected by the modification of the target function by a method similar to the method of polarized orbitals and they are close to the phase shifts calculated earlier by Bhatia [Phys. Rev. A 69, 032714 (2004)]. This indicates that the correlation function is general enough to include the target distortion (polarization) in the presence of the incident electron. The important fact is that in the present calculation, to obtain similar results only a 20-term correlation function is needed in the wave function compared to the 220- term wave function required in the above-mentioned calculation. Results for the phase shifts, obtained in the present hybrid formalism, are rigorous lower bounds to the exact phase shifts. The lowest P-wave resonances in He atom and hydrogen ion have been calculated and compared with the results obtained using the Feshbach projection operator formalism [Phys. Rev. A, 11, 2018 (1975)]. It is concluded that accurate resonance parameters can be obtained by the present method, which has the advantage of including corrections due to neighboring resonances, bound states and the continuum in which these resonance are embedded.
Whole-mantle P-wave velocity structure and azimuthal anisotropy
Yamamoto, Y.; Zhao, D.
2009-12-01
There are some hotspot volcanoes on Earth, such as Hawaii and Iceland. The mantle plume hypothesis was proposed forty years ago to explain hotspot volcanoes (e.g., Wilson, 1963; Morgan, 1971). Seismic tomography is a powerful technique to detect mantle plumes and determine their detailed structures. We determined a new whole-mantle 3-D P-wave velocity model (Tohoku model) using a global tomography method (Zhao, 2004, 2009). A flexible-grid approach with a grid interval of ~200 km is adopted to conduct the tomographic inversion. Our model shows that low-velocity (low-V) anomalies with diameters of several hundreds of kilometers are visible from the core-mantle boundary (CMB) to the surface under the major hotspot regions. Under South Pacific where several hotspots including Tahiti exist, there is a huge low-V anomaly from the CMB to the surface. This feature is consistent with the previous models. We conducted extensive resolution tests in order to understand whether this low-V anomaly shows a single superplume or a plume cluster. Unfortunately this problem is still not resolved because the ray path coverage in the mantle under South Pacific is not good enough. A network of ocean bottom seismometers is necessary to solve this problem. To better understand the whole-mantle structure and dynamics, we also conducted P-wave tomographic inversions for the 3-D velocity structure and azimuthal anisotropy. At each grid node there are three unknown parameters: one represents the isotropic velocity, the other two represent the azimuthal anisotropy. Our results show that in the shallow part of the mantle (Japan trench axis. In the Tonga subduction zone, the FVD is also perpendicular to the trench axis. Under the Tibetan region the FVD is NE-SW, which is parallel to the direction of the India-Asia collision. In the deeper part of the upper mantle and in the lower mantle, the amplitude of anisotropy is reduced. One interesting feature is that the FVD aligns in a radiated fashion
P-wave excited {B}_{c}^{* * } meson photoproduction at the LHeC
Kai, He; Huan-Yu, Bi; Ren-You, Zhang; Xiao-Zhou, Li; Wen-Gan, Ma
2018-05-01
As an important sequential work of the S-wave {B}c(* ) ({}1{S}0({}3{S}1) ) meson production at the large hadron electron collider (LHeC), we investigate the production of the P-wave excited {B}c* * states (1 P 1 and 3 P J with J = 0, 1, 2) via photoproduction mechanism within the framework of nonrelativistic QCD at the LHeC. Generally, the {e}-+P\\to γ +g\\to {B}c* * +b+\\bar{c} process is considered as the main production mechanism at an electron–proton collider due to the large luminosity of the gluon. However, according to our experience on the S-wave {B}c(* ) meson production at the LHeC, the extrinsic production mechanism, i.e., {e}-+P\\to γ +c\\to {B}c* * +b and {e}-+P\\to γ +\\bar{b} \\to {B}c* * +\\bar{c}, could also provide dominating contributions at low p T region. A careful treatment between these channels is performed and the results on total and differential cross sections, together with main uncertainties are discussed. Taking the quark masses m b = 4.90 ± 0.40 GeV and m c = 1.50 ± 0.20 GeV into account and summing up all the production channels, we expect to accumulate ({2.48}-1.75+3.55)× {10}4 {B}c* * ({}1{P}1), ({1.14}-0.82+1.49)× {10}4 {B}c* * ({}3{P}0),({2.38}-1.74+3.39)× {10}4 {B}c* * ({}3{P}1) and ({5.59}-3.93+7.84)× {10}4 {B}c* * ({}3{P}2) events at the \\sqrt{S}=1.30 {{T}}{{e}}{{V}} LHeC in one operation year with luminosity { \\mathcal L }={10}33 cm‑2 s‑1. With such sizable events, it is worth studying the properties of excited P-wave {B}c* * states at the LHeC.
Imaging the 2017 MW 8.2 Tehuantepec intermediate-depth earthquake using Teleseismic P Waves
Brudzinski, M.; Zhang, H.; Koper, K. D.; Pankow, K. L.
2017-12-01
The September 8, 2017 MW 8.1 Tehuantepec, Mexico earthquakes in the middle American subduction zone is one of the largest intermediate-depth earthquake ever recorded and could provide an unprecedented opportunity for understanding the mechanism of intermediate-depth earthquakes. While the hypocenter and centroid depths for this earthquake are shallower than typically considered for intermediate depth earthquakes, the normal faulting mechanism consistent with down-dip extension and location within the subducting plate align with properties of intermediate depth earthquakes. Back-projection of high-frequency teleseismic P-waves from two regional arrays for this earthquake shows unilateral rupture on a southeast-northwest striking fault that extends north of the Tehuantepec fracture zone (TFZ), with an average horizontal rupture speed of 3.0 km/s and total duration of 60 s. Guided by these back-projection results, 47 globally distributed low-frequency P-waves were inverted for a finite-fault model (FFM) of slip for both nodal planes. The FFM shows a slip deficit in proximity to the extension of the TFZ, as well as the minor rupture beyond the TFZ (confirmed by the synthetic tests), which indicates that the TFZ acted as a barrier for this earthquake. Analysis of waveform misfit leads to the preference of a subvertical plane as the causative fault. The FFM shows that the majority of the rupture is above the focal depth and consists of two large slip patches: the first one is near the hypocenter ( 55 km depth) and the second larger one near 30 km depth. The distribution of the two patches spatially agrees with seismicity that defines the upper and lower zones of a double Benioff zone (DBZ). It appears there was single fault rupture across the two depth zones of the DBZ. This is uncommon because a stark aseismic zone is typically observed between the upper and lower zones of the DBZ. This finding indicates that the mechanism for intraslab earthquakes must allow for
P-wave and QT dispersion in patients with conversion disorder
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Izci F
2015-03-01
Full Text Available Filiz Izci,1 Hilal Hocagil,2 Servet Izci,3 Vedat Izci,4 Merve Iris Koc,5 Rezzan Deniz Acar3 1Department of Psychiatry, Istanbul Bilim University, Sisli Florence Nightingale Hospital; 2Department of Emergency, Faculty of Medicine Hospital Zonguldak Bulent Ecevit University, Zonguldak, Turkey; 3Department of Cardiology, Kosuyolu High Specialization Training and Research Hospital, Istanbul, Turkey; 4Department of Emergency, Kartal Training and Research Hospital, Istanbul, Turkey; 5Department of Psychiatry, Erenköy Training and Research Hospital for Psychiatry, Istanbul, Turkey Objective: The aim of this study was to investigate QT dispersion (QTd, which is the noninvasive marker of ventricular arrhythmia and sudden cardiac death, and P-wave dispersion, which is the noninvasive marker of atrial arrhythmia, in patients with conversion disorder (CD.Patients and methods: A total of 60 patients with no known organic disease who were admitted to outpatient emergency clinic and were diagnosed with CD after psychiatric consultation were included in this study along with 60 healthy control subjects. Beck Anxiety Inventory and Beck Depression Scale were administered to patients and 12-lead electrocardiogram measurements were obtained. Pd and QTd were calculated by a single blinded cardiologist.Results: There was no statistically significant difference in terms of age, sex, education level, socioeconomic status, weight, height, and body mass index between CD patients and controls. Beck Anxiety Inventory scores (25.2±10.8 and 3.8±3.2, respectively, P<0.001 and Beck Depression Scale scores (11.24±6.15 and 6.58±5.69, respectively, P<0.01 were significantly higher in CD patients. P-wave dispersion measurements did not show any significant differences between conversion patients and control group (46±5.7 vs 44±5.5, respectively, P=0.156. Regarding QTc and QTd, there was a statistically significant increase in all intervals in conversion patients (416
Expert AE signal arrival detection
Czech Academy of Sciences Publication Activity Database
Chlada, Milan; Převorovský, Zdeněk
2011-01-01
Roč. 6, 3/4 (2011), s. 191-205 ISSN 1741-8410. [NDT in PROGRESS /4./. Praha, 05.11.2007-07.11.2007] R&D Projects: GA MPO(CZ) FR-TI1/274; GA ČR GA101/07/1518 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustic emission * signal arrival detection Subject RIV: BI - Acoustics http://www.inderscience.com/search/index.php?mainAction=search& action =record&rec_id=43215&prevQuery=&ps=10&m=or
1996-01-01
NASA and McDonnell Douglas Corporation (MDC) personnel steady the X-36 Tailless Fighter Agility Research Aircraft following arrival at NASA Dryden Flight Research Center, Edwards, California, on July 2, 1996. The aircraft is being hoisted out of it's shipping crate. The NASA/Boeing X-36 Tailless Fighter Agility Research Aircraft program successfully demonstrated the tailless fighter design using advanced technologies to improve the maneuverability and survivability of possible future fighter aircraft. The program met or exceeded all project goals. For 31 flights during 1997 at the Dryden Flight Research Center, Edwards, California, the project team examined the aircraft's agility at low speed / high angles of attack and at high speed / low angles of attack. The aircraft's speed envelope reached up to 206 knots (234 mph). This aircraft was very stable and maneuverable. It handled very well. The X-36 vehicle was designed to fly without the traditional tail surfaces common on most aircraft. Instead, a canard forward of the wing was used as well as split ailerons and an advanced thrust-vectoring nozzle for directional control. The X-36 was unstable in both pitch and yaw axes, so an advanced, single-channel digital fly-by-wire control system (developed with some commercially available components) was put in place to stabilize the aircraft. Using a video camera mounted in the nose of the aircraft and an onboard microphone, the X-36 was remotely controlled by a pilot in a ground station virtual cockpit. A standard fighter-type head-up display (HUD) and a moving-map representation of the vehicle's position within the range in which it flew provided excellent situational awareness for the pilot. This pilot-in-the-loop approach eliminated the need for expensive and complex autonomous flight control systems and the risks associated with their inability to deal with unknown or unforeseen phenomena in flight. Fully fueled the X-36 prototype weighed approximately 1,250 pounds
What is the difference in the p-wave and s-wave photodetachment in an electric field?
Du, M. L.
2009-01-01
By applying closed-orbit theory to an existing model, a simple formula is derived for the modulation function of s-wave photo-detachment in the presence of a static electric field. We then compare the s-wave modulation function with the p-wave modulation function. We show the maximums (minimums) in the s-wave modulation function correspond to the minimums (maximums) in the p-wave modulation function because of a phase difference of $\\pi$ in their oscillations. The oscillation amplitude in the...
Di-Neutral Pion Production in the Triplet P Wave States of Charmonium
Energy Technology Data Exchange (ETDEWEB)
Vidnovic, Theodore, III [Minnesota U.
2002-12-01
Fermilab experiment E835 has used proton-antiproton annihilations to perform a search for charmonium in the $\\pi^0 \\pi^0$ final state in the triplet P-wave region (3340-3570 MeV). States with even total angular momentum and positive Parity and C-parity have access to the $\\pi^0 \\pi^0$ final state. An enhancement in the $p\\bar{p} \\to \\pi^0 \\pi^0$ cross section was observed at the $X_{c0}$ resonance. The enhancement was found to be a factor of 20 larger than the expected resonant cross section and was attributed to interference between the $X_{c0}$ and the large non-resonant continuum. The general helicity structure of the $\\pi^0 \\pi^0$ differential cross section was studied and the product of the branching fractions, $Br(p\\bar{p}\\to X_{c0}$ ) x Br($X_{c0} \\to \\pi^0 \\pi^0$ ) = (5.09 ± 0.81(stat) ± 0.25 (sys) x $10^{-7}$ was measured.
Finite nuclear size and Lamb shift of p-wave atomic states
International Nuclear Information System (INIS)
Milstein, A.I.; Sushkov, O.P.; Terekhov, I.S.
2003-01-01
We consider corrections to the Lamb shift of the p-wave atomic states due to the finite nuclear size (FNS). In other words, these are radiative corrections to the atomic isotope shift related to the FNS. It is shown that the structure of the corrections is qualitatively different to that for the s-wave states. The perturbation theory expansion for the relative correction for a p 1/2 state starts with a α ln(1/Zα) term, while for the s 1/2 states it starts with a Zα 2 term. Here, α is the fine-structure constant and Z is the nuclear charge. In the present work, we calculate the α terms for that 2p states, the result for the 2p 1/2 state reads (8α/9π){ln[1/(Zα) 2 ]+0.710}. Even more interesting are the p 3/2 states. In this case the 'correction' is several orders of magnitude larger than the 'leading' FNS shift. However, absolute values of energy shifts related to these corrections are very small
Pure Quasi-P-wave calculation in transversely isotropic media using a hybrid method
Wu, Zedong
2018-04-12
The acoustic approximation for anisotropic media is widely used in current industry imaging and inversion algorithms mainly because P-waves constitute the majority of the energy recorded in seismic exploration. The resulting acoustic formulas tend to be simpler, resulting in more efficient implementations, and depend on fewer medium parameters. However, conventional solutions of the acoustic wave equation with higher-order derivatives suffer from shear wave artifacts. Thus, we derive a new acoustic wave equation for wave propagation in transversely isotropic (TI) media, which is based on a partially separable approximation of the dispersion relation for TI media and free of shear wave artifacts. Even though our resulting equation is not a partial differential equation, it is still a linear equation. Thus, we propose to implement this equation efficiently by combining the finite difference approximation with spectral evaluation of the space-independent parts. The resulting algorithm provides solutions without the constrain of ε ≥ δ. Numerical tests demonstrate the effectiveness of the approach.
Hybrid Theory of P-Wave Electron-Hydrogen Elastic Scattering
Bhatia, Anand
2012-01-01
We report on a study of electron-hydrogen scattering, using a combination of a modified method of polarized orbitals and the optical potential formalism. The calculation is restricted to P waves in the elastic region, where the correlation functions are of Hylleraas type. It is found that the phase shifts are not significantly affected by the modification of the target function by a method similar to the method of polarized orbitals and they are close to the phase shifts calculated earlier by Bhatia. This indicates that the correlation function is general enough to include the target distortion (polarization) in the presence of the incident electron. The important fact is that in the present calculation, to obtain similar results only 35-term correlation function is needed in the wave function compared to the 220-term wave function required in the above-mentioned previous calculation. Results for the phase shifts, obtained in the present hybrid formalism, are rigorous lower bounds to the exact phase shifts.
Inclusive decays of {eta}{sub b} into S- and P-wave charmonium states
Energy Technology Data Exchange (ETDEWEB)
He, Zhi-Guo, E-mail: hzgzlh@gmail.co [Institute of High Energy Physics, Chinese Academy of Science, P.O. Box 918(4), Beijing, 100049 (China); Theoretical Physics Center for Science Facilities, Beijing, 100049 (China); Li, Bai-Qing [Department of Physics, Huzhou Teachers College, Huzhou, 313000 (China)
2010-09-20
Inclusive S- and P-wave charmonium productions in the bottomonium ground state {eta}{sub b} decay are calculated at the leading order in the strong coupling constant {alpha}{sub s} and quarkonium internal relative velocity v in the framework of the NRQCD factorization approach. We find the contribution of {eta}{sub b{yields}{chi}c{sub J}}+gg followed by {chi}{sub c{sub J{yields}}}J/{psi}+{gamma} is also very important to inclusive J/{psi} production in the {eta}{sub b} decays, which maybe helpful to the investigation of the color-octet mechanism in the inclusive J/{psi} production in the {eta}{sub b} decays in the forthcoming LHCb and SuperB. As a complementary work, we also study the inclusive production of {eta}{sub c}, and {chi}{sub cJ} in the {eta}{sub b} decays, which may help us understand the X(3940) and X(3872) states.
P-wave and QT dispersion in patients with conversion disorder.
Izci, Filiz; Hocagil, Hilal; Izci, Servet; Izci, Vedat; Koc, Merve Iris; Acar, Rezzan Deniz
2015-01-01
The aim of this study was to investigate QT dispersion (QTd), which is the noninvasive marker of ventricular arrhythmia and sudden cardiac death, and P-wave dispersion, which is the noninvasive marker of atrial arrhythmia, in patients with conversion disorder (CD). A total of 60 patients with no known organic disease who were admitted to outpatient emergency clinic and were diagnosed with CD after psychiatric consultation were included in this study along with 60 healthy control subjects. Beck Anxiety Inventory and Beck Depression Scale were administered to patients and 12-lead electrocardiogram measurements were obtained. Pd and QTd were calculated by a single blinded cardiologist. There was no statistically significant difference in terms of age, sex, education level, socioeconomic status, weight, height, and body mass index between CD patients and controls. Beck Anxiety Inventory scores (25.2±10.8 and 3.8±3.2, respectively, Pconversion patients and control group (46±5.7 vs 44±5.5, respectively, P=0.156). Regarding QTc and QTd, there was a statistically significant increase in all intervals in conversion patients (416±10 vs 398±12, Pdisorders was also observed in CD patients. QTc and QTd were significantly increased compared to the control group in patients with CD. These results suggest a possibility of increased risk of ventricular arrhythmia resulting from QTd in CD patients. Larger samples are needed to evaluate the clinical course and prognosis in terms of arrhythmia risk in CD patients.
Pure Quasi-P-wave calculation in transversely isotropic media using a hybrid method
Wu, Zedong; Liu, Hongwei; Alkhalifah, Tariq Ali
2018-01-01
The acoustic approximation for anisotropic media is widely used in current industry imaging and inversion algorithms mainly because P-waves constitute the majority of the energy recorded in seismic exploration. The resulting acoustic formulas tend to be simpler, resulting in more efficient implementations, and depend on fewer medium parameters. However, conventional solutions of the acoustic wave equation with higher-order derivatives suffer from shear wave artifacts. Thus, we derive a new acoustic wave equation for wave propagation in transversely isotropic (TI) media, which is based on a partially separable approximation of the dispersion relation for TI media and free of shear wave artifacts. Even though our resulting equation is not a partial differential equation, it is still a linear equation. Thus, we propose to implement this equation efficiently by combining the finite difference approximation with spectral evaluation of the space-independent parts. The resulting algorithm provides solutions without the constrain of ε ≥ δ. Numerical tests demonstrate the effectiveness of the approach.
Higher Fock states and power counting in exclusive P-wave quarkonium decays
Bolz, J; Schuler, G A; Bolz, Jan; Kroll, Peter; Schuler, Gerhard A.
1998-01-01
Exclusive processes at large momentum transfer Q factor into perturbatively calculable short-distance parts and long-distance hadronic wave functions. Usually, only contributions from the leading Fock states have to be included to leading order in 1/Q. We show that for exclusive decays of P-wave quarkonia the contribution from the next-higher Fock state |Q Qbar g> contributes at the same order in 1/Q. We investigate how the constituent gluon attaches to the hard process in order to form colour-singlet final-state hadrons and argue that a single additional long-distance factor is sufficient to parametrize the size of its contribution. Incorporating transverse degrees of freedom and Sudakov factors, our results are perturbatively stable in the sense that soft phase-space contributions are largely suppressed. Explicit calculations yield good agreement with data on chi_{c J} decays into pairs of pions, kaons, and etas. We also comment on J/psi decays into two pions.
Soto-Bustos, Ángel; Caro-Vadillo, Alicia; Martínez-DE-Merlo, Elena; Alonso-Alegre, Elisa González
2017-10-07
The purpose of this research was to compare the accuracy of newly described P wave-related parameters (P wave area, Macruz index and mean electrical axis) with classical P wave-related parameters (voltage and duration of P wave) for the assessment of left atrial (LA) size in dogs with degenerative mitral valve disease. One hundred forty-six dogs (37 healthy control dogs and 109 dogs with degenerative mitral valve disease) were prospectively studied. Two-dimensional echocardiography examinations and a 6-lead ECG were performed prospectively in all dogs. Echocardiography parameters, including determination of the ratios LA diameter/aortic root diameter and LA area/aortic root area, were compared to P wave-related parameters: P wave area, Macruz index, mean electrical axis voltage and duration of P wave. The results showed that P wave-related parameters (classical and newly described) had low sensitivity (range=52.3 to 77%; median=60%) and low to moderate specificity (range=47.2 to 82.5%; median 56.3%) for the prediction of left atrial enlargement. The areas under the curve of P wave-related parameters were moderate to low due to poor sensitivity. In conclusion, newly P wave-related parameters do not increase the diagnostic capacity of ECG as a predictor of left atrial enlargement in dogs with degenerative mitral valve disease.
Quasi-Birth-and-Death Processes with Rational Arrival Process Components
DEFF Research Database (Denmark)
Bean, Nigel G.; Nielsen, Bo Friis
to develop an analytic method for such a process, that parallels the analysis of a traditional QBD. We demonstrate the analysis by considering a queue where the arrival process and the sequence of service times are derived from two different RAPs that are not just Markovian Arrival processes. We also...... introduce an element of correlation between the arrival process and the sequence of service times.......In this paper we introduce the concept of a Quasi-Birth-and-Death process (QBD) with Rational Arrival Process components. We use the physical interpretation of a Rational Arrival Process (RAP), developed by Asmussen and Bladt, to consider such a Markov process. We exploit this interpretation...
Locating Microseism Sources Using Spurious Arrivals in Intercontinental Noise Correlations
Retailleau, Lise; Boué, Pierre; Stehly, Laurent; Campillo, Michel
2017-10-01
The accuracy of Green's functions retrieved from seismic noise correlations in the microseism frequency band is limited by the uneven distribution of microseism sources at the surface of the Earth. As a result, correlation functions are often biased as compared to the expected Green's functions, and they can include spurious arrivals. These spurious arrivals are seismic arrivals that are visible on the correlation and do not belong to the theoretical impulse response. In this article, we propose to use Rayleigh wave spurious arrivals detected on correlation functions computed between European and United States seismic stations to locate microseism sources in the Atlantic Ocean. We perform a slant stack on a time distance gather of correlations obtained from an array of stations that comprises a regional deployment and a distant station. The arrival times and the apparent slowness of the spurious arrivals lead to the location of their source, which is obtained through a grid search procedure. We discuss improvements in the location through this methodology as compared to classical back projection of microseism energy. This method is interesting because it only requires an array and a distant station on each side of an ocean, conditions that can be met relatively easily.
Czech Academy of Sciences Publication Activity Database
Farra, V.; Pšenčík, Ivan
2016-01-01
Roč. 60, č. 3 (2016), s. 403-418 ISSN 0039-3169 Institutional support: RVO:67985530 Keywords : weak anisotropy * P-wave * phase velocity * ray velocity Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.764, year: 2016
Irdem, Ahmet; Aydın Sahin, Derya; Kervancioglu, Mehmet; Baspinar, Osman; Sucu, Murat; Keskin, Mehmet; Kilinc, Metin
2016-09-01
This study aimed to evaluate ventricular diastolic dysfunction, inter- and intraatrial conduction delay, and P-wave dispersion in pediatric patients with subclinical hypothyroidism. The study comprised a total of 30 pediatric patients with subclinical hypothyroidism (SH) (mean age 7.8 ± 3.2 years) and 30 healthy children (mean age 8.4 ± 3.6 years) as the control group. A SH diagnosis was made in the event of increased serum thyroid-stimulating hormone (TSH) and decreased serum free triiodothyronine (T3 ) and free thyroxine (T4 ) concentrations. Conventional Doppler imaging (TDI) showed low mitral early diastolic E-wave velocity and E/A ratio (P wave velocity (P = 0.001) in hypothyroidism patients. Moreover, patients with hypothyroidism had significantly lower left ventricular (LV) septal Em velocity and Em /Am ratios compared with the control group (P wave dispersion was significantly different in the pediatric patients with hypothyroidism (P wave dispersion, and ventricle diastolic dysfunction in pediatric patients with hypothyroidism. © 2016, Wiley Periodicals, Inc.
P-wave Velocity Structure Across the Mariana Trench and Implications for Hydration
Eimer, M. O.; Wiens, D.; Lizarralde, D.; Cai, C.
2017-12-01
Estimates of the water flux at subduction zones remain uncertain, particularly the amount of water brought into the trench by the subducting plate. Normal faulting related to the bending of the incoming plate has been proposed to provide pathways for water to hydrate the crust and upper mantle. A passive and active source seismic experiment spanning both the incoming plate and forearc was conducted in 2012 in central Mariana to examine the role of hydration at subduction zones. The active-source component of the survey used the R/V M.G. Langsethairgun array and 68 short period sensors, including suspended hydrophones, deployed on 4 transects. This study at the Mariana trench offers a comparison to related studies of incoming plate hydration in Middle America, where differing thermal structures related to plate age predict different stability fields for hydrous minerals. The forearc structure is also of interest, since Mariana is characterized by large serpentine seamounts and may have a serpentinized mantle wedge. The velocity structure will also be important for the relocation of earthquakes in the incoming plate, since the seismicity can offer a constraint for the depth extent of these bending faults. We examine the P-wave velocity structure along a 400-km long wide-angle refraction transect perpendicular to the trench and spanning both the forearc and incoming plate. Preliminary results indicate a velocity reduction in the crust and uppermost mantle at the bending region of the incoming plate, relative to the plate's structure away from the trench. This reduction suggests that outer-rise faults extend into the upper mantle and may have promoted serpentinization of that material. Mantle Pn refraction phases are not observed in the forearc, consistent with the ambient noise tomography results that show upper-mantle velocities similar to that of the lower crust. The lack of contrast between the upper mantle and crustal velocities from the ambient noise has been
Matonti, C.; Guglielmi, Y.; Viseur, S.; Garambois, S.; Marié, L.
2017-05-01
Fracture properties are important in carbonate reservoir characterization, as they are responsible for a large part of the fluid transfer properties at all scales. It is especially true in tight rocks where the matrix transfer properties only slightly contribute to the fluid flow. Open fractures are known to strongly affect seismic velocities, amplitudes and anisotropy. Here, we explore the impact of fracture evolution on the geophysical signature and directional Vp anisotropy of fractured carbonates through diagenesis. For that purpose, we studied a meter-scale, parallelepiped quarry block of limestone using a detailed structural and diagenetic characterization, and numerous Vp measurements. The block is affected by two en-échelon fracture clusters, both being formed in opening mode (mode 1) and cemented, but only one being reactivated in shear. We compared the diagenetic evolution of the fractures, which are almost all 100% filled with successive calcite cements, with the P-wave velocities measured across this meter-scale block of carbonate, which recorded the tectonic and diagenetic changes of a South Provence sedimentary basin. We found that a directional Vp anisotropy magnitude as high as 8-16% correlates with the reactivated fractures' cluster dip angle, which is explained by the complex filling sequence and softer material present inside the fractures that have been reactivated during the basin's tectonic inversion. We show that although a late karstification phase preferentially affected these reactivated fractures, it only amplified the pre-existing anisotropy due to tectonic shear. We conclude that Vp anisotropy measurements may help to identify the fracture sealing/opening processes associated with polyphased tectonic history, the anisotropy being independent of the current stress-state. This case shows that velocity anisotropies induced by fractures resulted here from a cause that is different from how these features have often been interpreted
Hussain, S.; Davis, T.
2012-12-01
Static and dynamic reservoir characterization was done on high resolution P-wave seismic data in Delhi Field, LA to study the complex stratigraphy of the Holt-Bryant sands and to delineate the CO2 flow path. The field is undergoing CO2 injection for enhanced oil recovery. The seismic data was bandwidth extended by Geotrace to decrease the tuning thickness effect. Once the authenticity of the added frequencies in the data was determined, the interpretation helped map thin Tuscaloosa and Paluxy sands. Cross-equalization was done on the baseline and monitor surveys to remove the non-repeatable noise in the data. Acoustic impedance (AI) inversion was done on the baseline and monitor surveys to map the changes in AI with CO2 injection in the field. Figure 1 shows the AI percentage change at Base Paluxy. The analysis helped identify areas that were not being swept by CO2. Figure 2 shows the CO2 flow paths in Tuscaloosa formation. The percentage change of AI with CO2 injection and pressure increase corresponded with the fluid substitution modeling results. Time-lapse interpretation helped in delineating the channels, high permeability zones and the bypassed zones in the reservoir.; Figure 1: P-impedance percentage difference map with a 2 ms window centered at the base of Paluxy with the production data from June 2010 overlain; the black dashed line is the oil-water contact; notice the negative impedance change below the OWC. The lighter yellow color shows area where Paluxy is not being swept completely. ; Figure 2: P-impedance percentage difference map at TUSC 7 top; the white triangles are TUSC 7 injectors and the white circles are TUSC 7 producers; the black polygons show the flow paths of CO2.
Strengthening economy through tourism sector by tourist arrival prediction
Supriatna, A.; Subartini, B.; Hertini, E.; Sukono; Rumaisha; Istiqamah, N.
2018-03-01
Tourism sector has a tendency to be proposed as a support for national economy to many countries with various of natural resources, such as Indonesia. The number of tourist is very related with the success rate of a tourist attraction, since it is also related with planning and strategy. Hence, it is important to predict the climate of tourism in Indonesia, especially the number of domestic or international tourist in the future. This study uses Seasonal Autoregressive Integrated Moving Average (SARIMA) time series method to predict the number of tourist arrival to tourism strategic areas in Nusa Tenggara Barat. The prediction was done using the international and domestic tourist arrival to Nusa Tenggara Barat data from January 2008 to June 2016. The established SARIMA method was (0,1,1)(0,0,2)12 with MAPE error of 15.76. The prediction for the next six time periods showed that the highest number of tourist arrival is during September 2016 with 330,516 tourist arrivals. Prediction of tourist arrival hopefully might be used as reference for local and national government to make policies to strengthen national economy for a long period of time
Chhabra, Lovely; Chaubey, Vinod K; Kothagundla, Chandrasekhar; Bajaj, Rishi; Kaul, Sudesh; Spodick, David H
2013-01-01
Pulmonary emphysema causes several electrocardiogram changes, and one of the most common and well known is on the frontal P-wave axis. P-axis verticalization (P-axis > 60°) serves as a quasidiagnostic indicator of emphysema. The correlation of P-axis verticalization with the radiological severity of emphysema and severity of chronic obstructive lung function have been previously investigated and well described in the literature. However, the correlation of P-axis verticalization in emphysema with other P-indices like P-terminal force in V1 (Ptf), amplitude of initial positive component of P-waves in V1 (i-PV1), and interatrial block (IAB) have not been well studied. Our current study was undertaken to investigate the effects of emphysema on these P-wave indices in correlation with the verticalization of the P-vector. Unselected, routinely recorded electrocardiograms of 170 hospitalized emphysema patients were studied. Significant Ptf (s-Ptf) was considered ≥40 mm.ms and was divided into two types based on the morphology of P-waves in V1: either a totally negative (-) P wave in V1 or a biphasic (+/-) P wave in V1. s-Ptf correlated better with vertical P-vectors than nonvertical P-vectors (P = 0.03). s-Ptf also significantly correlated with IAB (P = 0.001); however, IAB and P-vector verticalization did not appear to have any significant correlation (P = 0.23). There was a very weak correlation between i-PV1 and frontal P-vector (r = 0.15; P = 0.047); however, no significant correlation was found between i-PV1 and P-amplitude in lead III (r = 0.07; P = 0.36). We conclude that increased P-tf in emphysema may be due to downward right atrial position caused by right atrial displacement, and thus the common assumption that increased P-tf implies left atrial enlargement should be made with caution in patients with emphysema. Also, the lack of strong correlation between i-PV1 and P-amplitude in lead III or vertical P-vector may suggest the predominant role of downward
Liquid Argon Barrel Cryostat Arrived
Pailler, P
Last week the first of three cryostats for the ATLAS liquid argon calorimeter arrived at CERN. It had travelled for 46 days over several thousand kilometers from Japan to CERN. During three years it has been fabricated by Kawasaki Heavy Industries Ltd. at Harima, close to Kobe, under contract from Brookhaven National Laboratory (BNL) of the U.S.. This cryostat consists of two concentric cylinders made of aluminium: the outer vacuum vessel with a diameter of 5.5 m and a length of 7 m, and the inner cold vessel which will contain the electromagnetic barrel calorimeter immersed in liquid argon. The total weight will be 270 tons including the detectors and the liquid argon. The cryostat is now located in building 180 where it will be equipped with 64 feed-throughs which serve for the passage of 122,880 electrical lines which will carry the signals of the calorimeter. After integration of the calorimeter, the solenoidal magnet of ATLAS will be integrated in the vacuum vessel. A final cold test of the cryostat inc...
Mission Specialist Scott Parazynski arrives at KSC
1998-01-01
STS-95 Mission Specialist Scott E. Parazynski notes the time on his watch upon his late arrival aboard a T-38 jet at the Shuttle Landing Facility. Parazynski's first plane experienced problems at the stop at Tyndall AFB and he had to wait for another jet and pilot to finish the flight to KSC. He joined other crewmembers Mission Commander Curtis L. Brown Jr., Pilot Steven W. Lindsey, Mission Specialist Stephen K. Robinson, Payload Specialist John H. Glenn Jr., senator from Ohio, Mission Specialist Pedro Duque, with the European Space Agency (ESA), and Payload Specialist Chiaki Mukai, with the National Space Development Agency of Japan (NASDA), for final pre-launch preparations. STS-95 is expected to launch at 2 p.m. EST on Oct. 29, last 8 days, 21 hours and 49 minutes, and land at 11:49 a.m. EST on Nov. 7.
International Nuclear Information System (INIS)
Bruinsma, J.; Wageningen, R. van
1977-01-01
Nucleon-deuteron breakup calculations at a nucleon bombarding energy of 22.7 MeV have been performed with separable interactions including a tensor force and P-wave interactions. Differential cross sections and a selection of polarization quantities have been computed for special regions of the phase space. The influence of a tensor force and P-wave interactions on the differential cross section is of the order of 20%. Large discrepancies between theory and experiment occur for the vector analyzing powers, both for the kinematically complete and for the incomplete situation. The calculations show that there are kinematical situations in which the differential cross sections and the tensor analyzing powers are sufficiently large to make measurements feasible. (Auth.)
Czech Academy of Sciences Publication Activity Database
Gomes, E.; Zheng, Xuyao; Pšenčík, Ivan; Horne, S.; Leaney, S.
2004-01-01
Roč. 48, č. 1 (2004), s. 215-231 ISSN 0039-3169 R&D Projects: GA AV ČR IAA3012309; GA AV ČR KSK3012103 Grant - others:CHJFSS(CN) No.103021 Institutional research plan: CEZ:AV0Z3012916 Keywords : weak anisotropy * qP waves * walkaway VSP Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.447, year: 2004
Field, Michael E; Donateo, Paolo; Bottoni, Nicola; Iori, Matteo; Brignole, Michele; Kipp, Ryan T; Kopp, Douglas E; Leal, Miguel A; Eckhardt, Lee L; Wright, Jennifer M; Walsh, Kathleen E; Page, Richard L; Hamdan, Mohamed H
2018-04-19
The mechanism of inappropriate sinus tachycardia (IST) remains incompletely understood. We prospectively compared 3 patient groups: 11 patients with IST (IST Group), 9 control patients administered isoproterenol (Isuprel Group), and 15 patients with cristae terminalis atrial tachycardia (AT Group). P-wave amplitude in lead II and PR interval were measured at a lower and higher heart rate (HR1 and HR2, respectively). P-wave amplitude increased significantly with the increase in HR in the IST Group (0.16±0.07 mV at HR1=97±12 beats per minute versus 0.21±0.08 mV at HR2=135±21 beats per minute, P =0.001). The average increase in P-wave amplitude in the IST Group was similar to the Isuprel Group ( P =0.26). PR interval significantly shortened with the increases in HR in the IST Group (146±15 ms at HR1 versus 128±16 ms at HR2, P PR interval was noted in the Isuprel Group ( P =0.6). In contrast, patients in the atrial tachycardia Group experienced PR lengthening during atrial tachycardia when compared with baseline normal sinus rhythm (153±25 ms at HR1=78±17 beats per minute versus 179±29 ms at HR2=140±28 beats per minute, P PR shortening similar to what is seen in healthy controls following isoproterenol infusion. The increase in P-wave amplitude and absence of PR lengthening in IST support an extrinsic mechanism consistent with a state of sympatho-excitation with cephalic shift in sinus node activation and enhanced atrioventricular nodal conduction. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.
DEFF Research Database (Denmark)
Dixen, Ulrik; Wallevik, Laura; Hansen, Maja
2003-01-01
To evaluate the prognostic roles of prolonged signal-averaged P wave duration (SAPWD), raised levels of natriuretic peptides, and clinical characteristics in patients with stable congestive heart failure (CHF).......To evaluate the prognostic roles of prolonged signal-averaged P wave duration (SAPWD), raised levels of natriuretic peptides, and clinical characteristics in patients with stable congestive heart failure (CHF)....
The focusing effect of P-wave in the Moon's and Earth's low-velocity core. Analytical solution
Fatyanov, A. G.; Burmin, V. Yu
2018-04-01
The important aspect in the study of the structure of the interiors of planets is the question of the presence and state of core inside them. While for the Earth this task was solved long ago, the question of whether the core of the Moon is in a liquid or solid state up to the present is debatable up to present. If the core of the Moon is liquid, then the velocity of longitudinal waves in it should be lower than in the surrounding mantle. If the core is solid, then most likely, the velocity of longitudinal waves in it is higher than in the mantle. Numerical calculations of the wave field allow us to identify the criteria for drawing conclusions about the state of the lunar core. In this paper we consider the problem of constructing an analytical solution for wave fields in a layered sphere of arbitrary radius. A stable analytic solution is obtained for the wave fields of longitudinal waves in a three-layer sphere. Calculations of the total wave fields and rays for simplified models of the Earth and the Moon with real parameters are presented. The analytical solution and the ray pattern showed that the low-velocity cores of the Earth and the Moon possess the properties of a collecting lens. This leads to the emergence of a wave field focusing area. As a result, focused waves of considerable amplitude appear on the surface of the Earth and the Moon. In the Earth case, they appear before the first PKP-wave arrival. These are so-called "precursors", which continue in the subsequent arrivals of waves. At the same time, for the simplified model of the Earth, the maximum amplitude growth is observed in the 147-degree region. For the Moon model, the maximum amplitude growth is around 180°.
Sensitivity analysis of P-waves and S-waves to gas hydrate in the Shenhu area using OBS
Xing, Lei; Liu, Xueqin; Zhang, Jin; Liu, Huaishan; Zhang, Jing; Li, Zizheng; Wang, Jianhua
2018-02-01
Compared to towed streamers, ocean-bottom seismometers (OBS) obtain both S-wave data and richer wavefield information. In this paper, the induced polarization method is used to conduct wavefield separation on OBS data obtained from the Shenhu area in the South China Sea. A comparison of the changes in P- and S-waves, and a comprehensive analysis of geological factors within the area, enable analysis and description of the occurrence of natural gas hydrate in the study area. Results show an increase in P-wave velocity when natural gas hydrate exists in the formation, whereas the S-wave velocity remains almost constant, as S-waves can only propagate through the rock skeleton. Therefore, the bottom-simulating reflection (BSR) response of the P-wave is better than that of the S-wave in the frequency analysis profile. In a wide-angle section, the refractive wave of the hydrate layer is evident when using P-wave components but identification is difficult with S-wave components. This velocity model illustrates the sensitivity of P- and S-wave components to gas hydrate. The use of this polarization method and results of analysis provide technical and theoretical support for research on hydrate deposits and other geological features in the Shenhu area.
ON THE ARRIVAL TRAFFIC FLOW ORGANIZATION
Directory of Open Access Journals (Sweden)
Nikita A. Assorov
2017-01-01
Full Text Available This article is about air traffic flow organization, ICAO regulations describe the organizing of traffic flow as one of the purposes of air traffic control, but they don’t state exactly at what point the flow has to be organized and metered. The flight phase, where air traffic controller interferes with his instructions in order to begin organizing of all aircraft landing at a certain airport depends on the actual traffic volume per hour, airspace capacity and design.The example of air traffic situation in Moscow Domodedovo airport is described in the article, with runway 32 right in use, no significant weather, real usage of STARs, considering all the ICAO and Russian Federation regulations regarding speed control with the restrictions mentioned in AIP of Moscow Domodedovo. The purpose of the experiment is to prove the need of metering the air traffic flow on the entry points in Moscow TMA, because in case of unorganized air traffic flow approach controllers will have additional unnecessary workload.The conducted calculations show, that only 3 aircraft entering TMA on the same distance from initial approach point can be handled using only speed control and existing standard arrival procedures, in all other cases vectoring or holding areas should be used.In order to avoid such situations and increase the number of the aircraft that can be handled by the approach controller with less instructions, all the traffic arriving on the TMA entry point has to be metered by area control centre, because the air traffic control unit has much more space and time for long term speed control modifications, e.g. ±0,02 Mach. In conclusion a simple rule comes to mind – the bigger inbound traffic is, the earlier one has to organize it, in order to do it speed control, radar vectors, miles-in-trail can be used. Also new equipment and technology can help air traffic controller with this task, e.g. AMAN (arrival manager, in addition to this, the experience of
Directory of Open Access Journals (Sweden)
Alessandra Soler Bastos
2012-09-01
Full Text Available OBJETIVO: Caracterizar o perfil das pessoas com infarto agudo do miocárdio (IAM atendidas em um serviço de emergência e verificar o tempo de chegada (delta T. Identificar como o paciente foi transportado e correlacionar o delta T com o tratamento e prognóstico do mesmo. MÉTODOS: Pesquisa transversal, incluindo 52 pacientes admitidos na Unidade de Emergência de um Hospital de Ensino com diagnóstico de IAM, no período de julho a dezembro de 2010. A coleta de dados foi realizada por meio do prontuário e entrevista. RESULTADOS: A maioria dos pacientes era do gênero masculino, com idade média de 62,35 ± 14,66 anos, casada, poucos anos de estudo, histórico familiar de doença cardíaca, hipertensão arterial, dislipidemia e sedentarismo. Os sintomas apresentados foram dor no tórax, região epigástrica ou desconforto torácico associado à dispneia e/ou sudorese súbita. A maioria dos pacientes foi transportada por ambulância e submetida a cateterismo cardíaco, seguido de angioplastia. O delta T encontrado foi 9h54min ± 18h9min. A letalidade global do estudo foi de 3,85%. CONCLUSÃO: O reconhecimento dos sinais e sintomas do IAM pelo paciente foi fator determinante para a procura de atendimento especializado e aqueles com menor delta T apresentaram melhor prognóstico.OBJECTIVES: To characterize the profile of patients with acute myocardial infarction (AMI treated at the emergency department and to verify the time of arrival of each patient (ΔT. Identify how the patient was transported and to correlate Delta-T (ΔT with the treatment and the prognosis of each patient. METHODS: Cross-sectional survey involving 52 patients with AMI admitted to the Emergency Department of a Teaching Hospital took part in the study from July to December 2010. Data collection was performed using medical records and interviews. RESULTS: The majority of the patients were male with a mean age of 62.35 ± 14.66 years. The participants were married, with low
8 CFR 232.3 - Arriving aliens.
2010-01-01
... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL AND MENTAL EXAMINATION § 232.3 Arriving aliens. When a district director has reasonable grounds...
Modelling Chinese Inbound Tourism Arrivals into Christchurch
Fieger, Peter; Rice, John
2016-01-01
New data and modelling approaches are improving the usefulness of internet search data for forecasting inbound tourist arrivals. This short paper provides evidence of the usefulness of Baidu search data in predicting Chinese inbound tourist arrivals into a specific region in New Zealand. It also compares three modelling approaches, finding a Vector Autoregressive approach the most useful.
He, T.; Lu, H.; Yelisetti, S.; Spence, G.
2015-12-01
The submarine landslide associated with gas hydrate is a potential risk for environment and engineering projects, and thus from long time ago it has been a hot topic of hydrate research. The study target is Slipstream submarine landslide, one of the slope failures observed on the frontal ridges of the Northern Cascadia accretionary margin off Vancouver Island. The previous studies indicated a possible connection between this submarine landslide feature and gas hydrate, whose occurrence is indicated by a prominent bottom-simulating reflector (BSR), at a depth of ~265-275 m beneath the seafloor (mbsf). The OBS (Ocean Bottom Seismometer) data collected during SeaJade (Seafloor Earthquake Array - Japan Canada Cascadia Experiment) project were used to derive the subseafloor velocity structure for both P- and S-wave using travel times picked from refraction and reflection events. The P-wave velocity structure above the BSR showed anomalous high velocities of about 2.0 km/s at shallow depths of 100 mbsf, closely matching the estimated depth of the glide plane (100 ± 10 m). Forward modelling of S-waves was carried out using the data from the OBS horizontal components. The S-wave velocities, interpreted in conjunction with the P-wave results, provide the key constraints on the gas hydrate distribution within the pores. The hydrate distribution in the pores is important for determining concentrations, and also for determining the frame strength which is critical for controlling slope stability of steep frontal ridges. The increase in S-wave velocity suggests that the hydrate is distributed as part of the load-bearing matrix to increase the rigidity of the sediment.
Bartrand, J.; Abbott, R. E.
2017-12-01
We present data and analysis of a seismic data collect at the site of a historical underground nuclear explosion at Yucca Flat, a sedimentary basin on the Nevada National Security Site, USA. The data presented here consist of active-source, six degree-of-freedom seismic signals. The translational signals were collected with a Nanometrics Trillium Compact Posthole seismometer and the rotational signals were collected with an ATA Proto-SMHD, a prototype rotational ground motion sensor. The source for the experiment was the Seismic Hammer (a 13,000 kg weight-drop), deployed on two-kilometer, orthogonal arms centered on the site of the nuclear explosion. By leveraging the fact that compressional waves have no rotational component, we generated a map of subsurface scattering and compared the results to known subsurface features. To determine scattering intensity, signals were cut to include only the P-wave and its coda. The ratio of the time-domain signal magnitudes of angular velocity and translational acceleration were sectioned into three time windows within the coda and averaged within each window. Preliminary results indicate an increased rotation/translation ratio in the vicinity of the explosion-generated chimney, suggesting mode conversion of P-wave energy to S-wave energy at that location. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.
STS-114: Discovery Crew Arrival
2005-01-01
George Diller of NASA Public Affairs narrates the STS-114 Crew arrival at Kennedy Space Center aboard a Gulf Stream aircraft. They were greeted by Center Director Jim Kennedy. Commander Eileen Collins introduced each of her crew members and gave a brief description of their roles in the mission. Mission Specialist 3, Andrew Thomas will be the lead crew member on the inspection on flight day 2; he is the intravehicular (IV) crew member that will help and guide Mission Specialists Souichi Noguchi and Stephen Robinson during their spacewalks. Pilot James Kelly will be operating the shuttle systems in flying the Shuttle; he will be flying the space station robotic arm during the second extravehicular activity and he will be assisting Mission Specialist Wendy Lawrence during the other two extravehicular activities; he will be assisting on the rendezvous on flight day three, and landing of the shuttle. Commander Collins also mentioned Pilot Kelly's recent promotion to Colonel by the United States Air Force. Mission Specialist 1, Souichi Noguchi from JAXA (The Japanese Space Agency) will be flying on the flight deck for ascent; he will be doing three spacewalks on day 5, 7, and 9; He will be the photo/TV lead for the different types of cameras on board to document the flight and to send back the information to the ground for both technical and public affairs reasons. Mission Specialist 5, Charles Camada will be doing the inspection on flight day 2 with Mission Specialist Thomas and Pilot Kelly; he will be transferring the logistics off the shuttle and onto the space station and from the space station back to the shuttle; He will help set up eleven lap tops on board. Mission Specialist 4, Wendy Lawrence will lead the transfer of logistics to the space station; she is the space station arm operator during extravehicular activities 1 and 3; she will be carrying the 6,000 pounds of external storage platform from the shuttle payload bay over to the space station; she is also
Healthcare system information at language schools for newly arrived immigrants
DEFF Research Database (Denmark)
Tynell, Lena Lyngholt; Wimmelmann, Camilla Lawaetz; Jervelund, Signe Smith
2017-01-01
a language school in Copenhagen in 2012 received either a course or written information on the Danish healthcare system and subsequently evaluated this quantitatively. Results: The evaluation revealed a positive appraisal of the course/information provided. Conclusion: In times of austerity, incorporating......Objective: In most European countries, immigrants do not systematically learn about the host countries’ healthcare system when arriving. This study investigated how newly arrived immigrants perceived the information they received about the Danish healthcare system. Method: Immigrants attending...... healthcare information into an already existing language programme may be pertinent for providing immigrants with knowledge on the healthcare system....
Obtaining and utilizing contaminant arrival distributions in transient flow systems
International Nuclear Information System (INIS)
Anon.
1977-01-01
The versatility of the new contaminant arrival distributions for determining environmental consequences of subsurface pollution problems is demonstrated through application to a transient flow system. Though some of the four phases of the hydrologic evaluations are more complicated because of the time-dependence of the flow and input contaminant concentrations, the arrival distributions still effectively summarize the data required to determine the environmental implications. These arrival distributions yield two graphs or tabular sets of data giving the consequences of the subsurface pollution problems in a simple and direct form. Accordingly, the public control authorities would be able to use these results to choose alternatives or initiate corrective actions, depending on the indicated environmental consequences
Waveform inversion for orthorhombic anisotropy with P-waves: feasibility & resolution
Kazei, Vladimir
2018-01-27
Various parameterizations have been suggested to simplify inversions of first arrivals, or P −waves, in orthorhombic anisotropic media, but the number and type of retrievable parameters have not been decisively determined. We show that only six parameters can be retrieved from the dynamic linearized inversion of P −waves. These parameters are different from the six parameters needed to describe the kinematics of P −waves. Reflection-based radiation patterns from the P − P scattered waves are remapped into the spectral domain to allow for our resolution analysis based on the effective angle of illumination concept. Singular value decomposition of the spectral sensitivities from various azimuths, offset coverage scenarios, and data bandwidths allows us to quantify the resolution of different parameterizations, taking into account the signal-to-noise ratio in a given experiment. According to our singular value analysis, when the primary goal of inversion is determining the velocity of the P −waves, gradually adding anisotropy of lower orders (isotropic, vertically transversally isotropic, orthorhombic) in hierarchical parameterization is the best choice. Hierarchical parametrization reduces the tradeoff between the parameters and makes gradual introduction of lower anisotropy orders straightforward. When all the anisotropic parameters affecting P −wave propagation need to be retrieved simultaneously, the classic parameterization of orthorhombic medium with elastic stiffness matrix coefficients and density is a better choice for inversion. We provide estimates of the number and set of parameters that can be retrieved from surface seismic data in different acquisition scenarios. To set up an inversion process, the singular values determine the number of parameters that can be inverted and the resolution matrices from the parameterizations can be used to ascertain the set of parameters that can be resolved.
Tsunami Arrival Detection with High Frequency (HF Radar
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Donald Barrick
2012-05-01
Full Text Available Quantitative real-time observations of a tsunami have been limited to deep-water, pressure-sensor observations of changes in the sea surface elevation and observations of sea level fluctuations at the coast, which are essentially point measurements. Constrained by these data, models have been used for predictions and warning of the arrival of a tsunami, but to date no system exists for local detection of an actual incoming wave with a significant warning capability. Networks of coastal high frequency (HF-radars are now routinely observing surface currents in many countries. We report here on an empirical method for the detection of the initial arrival of a tsunami, and demonstrate its use with results from data measured by fourteen HF radar sites in Japan and USA following the magnitude 9.0 earthquake off Sendai, Japan, on 11 March 2011. The distance offshore at which the tsunami can be detected, and hence the warning time provided, depends on the bathymetry: the wider the shallow continental shelf, the greater this time. We compare arrival times at the radars with those measured by neighboring tide gauges. Arrival times measured by the radars preceded those at neighboring tide gauges by an average of 19 min (Japan and 15 min (USA The initial water-height increase due to the tsunami as measured by the tide gauges was moderate, ranging from 0.3 to 2 m. Thus it appears possible to detect even moderate tsunamis using this method. Larger tsunamis could obviously be detected further from the coast. We find that tsunami arrival within the radar coverage area can be announced 8 min (i.e., twice the radar spectral time resolution after its first appearance. This can provide advance warning of the tsunami approach to the coastline locations.
Computing angle of arrival of radio signals
Borchardt, John J.; Steele, David K.
2017-11-07
Various technologies pertaining to computing angle of arrival of radio signals are described. A system that is configured for computing the angle of arrival of a radio signal includes a cylindrical sheath wrapped around a cylindrical object, where the cylindrical sheath acts as a ground plane. The system further includes a plurality of antennas that are positioned about an exterior surface of the cylindrical sheath, and receivers respectively coupled to the antennas. The receivers output measurements pertaining to the radio signal. A processing circuit receives the measurements and computes the angle of arrival of the radio signal based upon the measurements.
Velmala, William; Helle, Samuli; Ahola, Markus P.; Klaassen, M.R.J.; Lehikoinen, Esa; Rainio, Kalle; Sirkia, Paivi M.; Laaksonen, Toni
2015-01-01
For migratory birds, the earlier arrival of males to breeding grounds is often expected to have fitness benefits. However, the selection differential on male arrival time has rarely been decomposed into the direct effect of male arrival and potential indirect effects through female traits. We
Directory of Open Access Journals (Sweden)
Chhabra L
2013-05-01
Full Text Available Lovely Chhabra,1 Vinod K Chaubey,1 Chandrasekhar Kothagundla,1 Rishi Bajaj,1 Sudesh Kaul,1 David H Spodick2 1Department of Internal Medicine, 2Department of Cardiovascular Diseases, University of Massachusetts Medical School, Worcester, MA, USA Introduction: Pulmonary emphysema causes several electrocardiogram changes, and one of the most common and well known is on the frontal P-wave axis. P-axis verticalization (P-axis > 60° serves as a quasidiagnostic indicator of emphysema. The correlation of P-axis verticalization with the radiological severity of emphysema and severity of chronic obstructive lung function have been previously investigated and well described in the literature. However, the correlation of P-axis verticalization in emphysema with other P-indices like P-terminal force in V1 (Ptf, amplitude of initial positive component of P-waves in V1 (i-PV1, and interatrial block (IAB have not been well studied. Our current study was undertaken to investigate the effects of emphysema on these P-wave indices in correlation with the verticalization of the P-vector. Materials and methods: Unselected, routinely recorded electrocardiograms of 170 hospitalized emphysema patients were studied. Significant Ptf (s-Ptf was considered ≥40 mm.ms and was divided into two types based on the morphology of P-waves in V1: either a totally negative (- P wave in V1 or a biphasic (+/- P wave in V1. Results: s-Ptf correlated better with vertical P-vectors than nonvertical P-vectors (P = 0.03. s-Ptf also significantly correlated with IAB (P = 0.001; however, IAB and P-vector verticalization did not appear to have any significant correlation (P = 0.23. There was a very weak correlation between i-PV1 and frontal P-vector (r = 0.15; P = 0.047; however, no significant correlation was found between i-PV1 and P-amplitude in lead III (r = 0.07; P = 0.36. Conclusion: We conclude that increased P-tf in emphysema may be due to downward right atrial position caused by
Hayashi, Shuji; Yamada, Hirotsugu; Bando, Mika; Saijo, Yoshihito; Nishio, Susumu; Hirata, Yukina; Klein, Allan L; Sata, Masataka
2015-08-01
Left atrial (LA) strain analysis using speckle tracking echocardiography is useful for assessing LA function. However, there is no established procedure for this method. Most investigators have determined the electrocardiographic R-wave peak as the starting point for LA strain analysis. To test our hypothesis that P-wave onset should be used as the starting point, we measured LA strain using 2 different starting points and compared the strain values with the corresponding LA volume indices obtained by three-dimensional (3D) echocardiography. We enrolled 78 subjects (61 ± 17 years, 25 males) with and without various cardiac diseases in this study and assessed global longitudinal LA strain by two-dimensional speckle tracking strain echocardiography using EchoPac software. We used either R-wave peak or P-wave onset as the starting point for determining LA strains during the reservoir (Rres, Pres), conduit (Rcon, Pcon), and booster pump (Rpump, Ppump) phases. We determined the maximum, minimum, and preatrial contraction LA volumes, and calculated the LA total, passive, and active emptying fractions using 3D echocardiography. The correlation between Pres and LA total emptying fraction was better than the correlation between Rres and LA total emptying fraction (r = 0.458 vs. 0.308, P = 0.026). Pcon and Ppump exhibited better correlation with the corresponding 3D echocardiographic parameters than Rcon (r = 0.560 vs. 0.479, P = 0.133) and Rpump (r = 0.577 vs. 0.345, P = 0.003), respectively. LA strain in any phase should be analyzed using P-wave onset as the starting point rather than R-wave peak. © 2014, Wiley Periodicals, Inc.
Imai, Yoshiki; Sigrist, Manfred
2018-05-01
Motivated by recent experiments on Sr2RuO4, the effect of uniaxial strain on the chiral p-wave superconductor is discussed. We study particularly the relation between the topological indices and different pairing states in the superconducting phase through the thermal Hall conductivity, which is proportional to temperature and the Chern number in the very low-temperature limit. We show that the temperature-dependence of the thermal Hall conductivity under uniaxial strain depends strongly on the form of the pairing state. The obtained result may provide a possible experimental probe for the pairing structure in Sr2RuO4.
Masmoudi, Nabil; Pšenčí k, Ivan
2014-01-01
We present an approximate, but efficient and sufficiently accurate P-wave ray tracing and dynamic ray tracing procedure for 3D inhomogeneous, weakly orthorhombic media with varying orientation of symmetry planes. In contrast to commonly used approaches, the orthorhombic symmetry is preserved at any point of the model. The model is described by six weak-anisotropy parameters and three Euler angles, which may vary arbitrarily, but smoothly, throughout the model. We use the procedure for the calculation of rays and corresponding two-point traveltimes in a VSP experiment in a part of the BP benchmark model generalized to orthorhombic symmetry.
Strategic Arrivals Recommendation Tool, Phase I
National Aeronautics and Space Administration — During the conduct of a NASA Research Announcement (NRA) in 2012 and 2013, the Mosaic ATM team first developed the Strategic Arrivals Recommendation Tool concept, or...
Two parallel finite queues with simultaneous services and Markovian arrivals
Directory of Open Access Journals (Sweden)
S. R. Chakravarthy
1997-01-01
Full Text Available In this paper, we consider a finite capacity single server queueing model with two buffers, A and B, of sizes K and N respectively. Messages arrive one at a time according to a Markovian arrival process. Messages that arrive at buffer A are of a different type from the messages that arrive at buffer B. Messages are processed according to the following rules: 1. When buffer A(B has a message and buffer B(A is empty, then one message from A(B is processed by the server. 2. When both buffers, A and B, have messages, then two messages, one from A and one from B, are processed simultaneously by the server. The service times are assumed to be exponentially distributed with parameters that may depend on the type of service. This queueing model is studied as a Markov process with a large state space and efficient algorithmic procedures for computing various system performance measures are given. Some numerical examples are discussed.
TOURIST ARRIVALS AND ECONOMIC GROWTH IN SARAWAK
Lau, Evan; Oh, Swee-Ling; Hu, Sing-Sing
2008-01-01
This study empirically investigates the comovements and the causality relationship between tourist arrivals and economic growth in Sarawak during the period of 1972 to 2004. The empirical evidence clearly shows that the long run causality running from tourist arrivals to economic growth in the estimation period. As one of the income generator for Sarawak, the findings are consistent with economic theory and proffer important policy conclusions.
A Maxwell-vector p-wave holographic superconductor in a particular background AdS black hole metric
Directory of Open Access Journals (Sweden)
Dan Wen
2018-05-01
Full Text Available We study the p-wave holographic superconductor for AdS black holes with planar event horizon topology for a particular Lovelock gravity, in which the action is characterized by a self-interacting scalar field nonminimally coupled to the gravity theory which is labeled by an integer k. As the Lovelock theory of gravity is the most general metric theory of gravity based on the fundamental assumptions of general relativity, it is a desirable theory to describe the higher dimensional spacetime geometry. The present work is devoted to studying the properties of the p-wave holographic superconductor by including a Maxwell field which nonminimally couples to a complex vector field in a higher dimensional background metric. In the probe limit, we find that the critical temperature decreases with the increase of the index k of the background black hole metric, which shows that a larger k makes it harder for the condensation to form. We also observe that the index k affects the conductivity and the gap frequency of the holographic superconductors.
A Maxwell-vector p-wave holographic superconductor in a particular background AdS black hole metric
Wen, Dan; Yu, Hongwei; Pan, Qiyuan; Lin, Kai; Qian, Wei-Liang
2018-05-01
We study the p-wave holographic superconductor for AdS black holes with planar event horizon topology for a particular Lovelock gravity, in which the action is characterized by a self-interacting scalar field nonminimally coupled to the gravity theory which is labeled by an integer k. As the Lovelock theory of gravity is the most general metric theory of gravity based on the fundamental assumptions of general relativity, it is a desirable theory to describe the higher dimensional spacetime geometry. The present work is devoted to studying the properties of the p-wave holographic superconductor by including a Maxwell field which nonminimally couples to a complex vector field in a higher dimensional background metric. In the probe limit, we find that the critical temperature decreases with the increase of the index k of the background black hole metric, which shows that a larger k makes it harder for the condensation to form. We also observe that the index k affects the conductivity and the gap frequency of the holographic superconductors.
Does pet arrival trigger prosocial behaviors in individuals with autism?
Directory of Open Access Journals (Sweden)
Marine Grandgeorge
Full Text Available Alteration of social interactions especially prosocial behaviors--an important aspect of development--is one of the characteristics of autistic disorders. Numerous strategies or therapies are used to improve communication skills or at least to reduce social impairments. Animal-assisted therapies are used widely but their relevant benefits have never been scientifically evaluated. In the present study, we evaluated the association between the presence or the arrival of pets in families with an individual with autism and the changes in his or her prosocial behaviors. Of 260 individuals with autism--on the basis of presence or absence of pets--two groups of 12 individuals and two groups of 8 individuals were assigned to: study 1 (pet arrival after age of 5 versus no pet and study 2 (pet versus no pet, respectively. Evaluation of social impairment was assessed at two time periods using the 36-items ADI-R algorithm and a parental questionnaire about their child-pet relationships. The results showed that 2 of the 36 items changed positively between the age of 4 to 5 (t(0 and time of assessment (t(1 in the pet arrival group (study 1: "offering to share" and "offering comfort". Interestingly, these two items reflect prosocial behaviors. There seemed to be no significant changes in any item for the three other groups. The interactions between individuals with autism and their pets were more--qualitatively and quantitatively--reported in the situation of pet arrival than pet presence since birth. These findings open further lines of research on the impact of pet's presence or arrival in families with an individual with autism. Given the potential ability of individuals with autism to develop prosocial behaviors, related studies are needed to better understand the mechanisms involved in the development of such child-pet relationship.
Does pet arrival trigger prosocial behaviors in individuals with autism?
Grandgeorge, Marine; Tordjman, Sylvie; Lazartigues, Alain; Lemonnier, Eric; Deleau, Michel; Hausberger, Martine
2012-01-01
Alteration of social interactions especially prosocial behaviors--an important aspect of development--is one of the characteristics of autistic disorders. Numerous strategies or therapies are used to improve communication skills or at least to reduce social impairments. Animal-assisted therapies are used widely but their relevant benefits have never been scientifically evaluated. In the present study, we evaluated the association between the presence or the arrival of pets in families with an individual with autism and the changes in his or her prosocial behaviors. Of 260 individuals with autism--on the basis of presence or absence of pets--two groups of 12 individuals and two groups of 8 individuals were assigned to: study 1 (pet arrival after age of 5 versus no pet) and study 2 (pet versus no pet), respectively. Evaluation of social impairment was assessed at two time periods using the 36-items ADI-R algorithm and a parental questionnaire about their child-pet relationships. The results showed that 2 of the 36 items changed positively between the age of 4 to 5 (t(0)) and time of assessment (t(1)) in the pet arrival group (study 1): "offering to share" and "offering comfort". Interestingly, these two items reflect prosocial behaviors. There seemed to be no significant changes in any item for the three other groups. The interactions between individuals with autism and their pets were more--qualitatively and quantitatively--reported in the situation of pet arrival than pet presence since birth. These findings open further lines of research on the impact of pet's presence or arrival in families with an individual with autism. Given the potential ability of individuals with autism to develop prosocial behaviors, related studies are needed to better understand the mechanisms involved in the development of such child-pet relationship.
Jolly, A.D.; Moran, S.C.; McNutt, S.R.; Stone, D.B.
2007-01-01
The three-dimensional P-wave velocity structure beneath the Katmai group of volcanoes is determined by inversion of more than 10,000 rays from over 1000 earthquakes recorded on a local 18 station short-period network between September 1996 and May 2001. The inversion is well constrained from sea level to about 6??km below sea level and encompasses all of the Katmai volcanoes; Martin, Mageik, Trident, Griggs, Novarupta, Snowy, and Katmai caldera. The inversion reduced the average RMS travel-time error from 0.22??s for locations from the standard one-dimensional model to 0.13??s for the best three-dimensional model. The final model, from the 6th inversion step, reveals a prominent low velocity zone (3.6-5.0??km/s) centered at Katmai Pass and extending from Mageik to Trident volcanoes. The anomaly has values about 20-25% slower than velocities outboard of the region (5.0-6.5??km/s). Moderately low velocities (4.5-6.0??km/s) are observed along the volcanic axis between Martin and Katmai Caldera. Griggs volcano, located about 10??km behind (northwest of) the volcanic axis, has unremarkable velocities (5.0-5.7??km/s) compared to non-volcanic regions. The highest velocities are observed between Snowy and Griggs volcanoes (5.5-6.5??km/s). Relocated hypocenters for the best 3-D model are shifted significantly relative to the standard model with clusters of seismicity at Martin volcano shifting systematically deeper by about 1??km to depths of 0 to 4??km below sea level. Hypocenters for the Katmai Caldera are more tightly clustered, relocating beneath the 1912 scarp walls. The relocated hypocenters allow us to compare spatial frequency-size distributions (b-values) using one-dimensional and three-dimensional models. We find that the distribution of b is significantly changed for Martin volcano, which was characterized by variable values (0.8 < b < 2.0) with standard locations and more uniform values (0.8 < b < 1.2) after relocation. Other seismic clusters at Mageik (1.2 < b
Analysis on the Impact of Pop-Up Flight Occurrence when Extending the Arrival Management Horizon
Ellerbroek, J.; Hoekstra, J.M.; Westerveld, E
2017-01-01
The occurrence of pop-up flights negatively affects the (extended) arrival manager. This issue is known already for a long time by operational experts, but the extent thereof has now been assessed during experiments. An arrival manager research model was developed and integrated in BlueSky, an
Directory of Open Access Journals (Sweden)
Nicpoń Józef
2011-03-01
Full Text Available Abstract Background P-wave dispersion (Pd is a new ECG index used in human cardiology and veterinary medicine. It is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different ECG leads. So far no studies were performed assessing the importance of P-wave dispersion in dogs. Methods The current study was aimed at determining proper value of Pd in healthy dogs (group I, dogs with chronic valvular disease (group II and dogs with disturbances of supraventricular conduction (group III. The tests were carried out in 53 healthy dogs, 23 dogs with chronic valvular disease and 12 dogs with disturbances of supraventricular conduction of various breeds, sexes and body weight from 1,5 to 80 kg, aged between 0,5 and 17 years, submitted to the ECG examination. ECG was acquired in dogs in a standing position with BTL SD-8 electrocardiographic device and analyzed once the recording was enlarged. P-wave duration was calculated in 9 ECG leads (I, II, III, aVR, aVL, aVF, V1, V2, V4 from 5 cardiac cycles. Results The proper P-wave dispersion in healthy dogs was determined at up to 24 ms. P-wave dispersion was statistically significant increased (p Conclusions The P-wave dispersion is a constant index in healthy dogs, that is why it can be used for evaluating P wave change in dogs with chronic valvular disease and in dogs with disturbances of supraventricular conduction.
Glaab, Patricia C.
2012-01-01
The first phase of this study investigated the amount of time a flight can be delayed or expedited within the Terminal Airspace using only speed changes. The Arrival Capacity Calculator analysis tool was used to predict the time adjustment envelope for standard descent arrivals and then for CDA arrivals. Results ranged from 0.77 to 5.38 minutes. STAR routes were configured for the ACES simulation, and a validation of the ACC results was conducted comparing the maximum predicted time adjustments to those seen in ACES. The final phase investigated full runway-to-runway trajectories using ACES. The radial distance used by the arrival scheduler was incrementally increased from 50 to 150 nautical miles (nmi). The increased Planning Horizon radii allowed the arrival scheduler to arrange, path stretch, and speed-adjust flights to more fully load the arrival stream. The average throughput for the high volume portion of the day increased from 30 aircraft per runway for the 50 nmi radius to 40 aircraft per runway for the 150 nmi radius for a traffic set representative of high volume 2018. The recommended radius for the arrival scheduler s Planning Horizon was found to be 130 nmi, which allowed more than 95% loading of the arrival stream.
Anaïs Schaeffer
2012-01-01
In 1970, CERN and ESO signed a collaboration agreement for the construction of the Observatory’s first telescope. That same year, ESO’s Telescope Division and Sky Atlas laboratory settled on the CERN site in Meyrin. Let’s turn back to the beginnings of this lasting and fruitful alliance. Martin Cullum, ESO physicist from 1973 to 2009 In 1974, when I attended my first international conference on behalf of ESO, the first thing people asked was: “Where are you from?” “ESO,” I would say. The response: ‘'What on Earth is ESO?” Nowadays, people I meet seem to know more about ESO than I do! It is clear that ESO profited enormously from its sojourn at CERN. The wise decision of the ESO Director General at the time, Adriaan Blaauw, to move to Geneva allowed ESO to build up its technical expertise to be able to build world-beating projects like the VLT, which has undoubtedly been the most exciting scientif...
Energy Technology Data Exchange (ETDEWEB)
Mensch, Th.
2000-01-12
The seismic anisotropy causes in the Earth are known. The anisotropy characterization can provide valuable informations on the structure, lithology or eventual deformation processes in geological media. The orthorhombic symmetry allows a more complete description and representation of the anisotropy than the transversely isotropy symmetry usually assumed. Moreover this symmetry is potentially common in sedimentary basins, and particularly in fractured reservoir. In anisotropic media of arbitrary symmetry (triclinic), there is no simple analytic expressions on the phase slowness surface. The weak anisotropy assumption, often reasonable in geological media, makes perturbation techniques relevant. An approximate first order analytical expression of the qP-wave slowness surface is obtained. Using an adequate parameterization, the forward problem is solved by the ray theory. The Hamiltonian formulation introduces by a simple way ray equations in anisotropic media. The rays, travel time and its Fruchet derivatives expressions, valid to first order, are given for orthorhombic inhomogeneous media. Perturbation method applied to the ray theory allows the development of fast ray tracing in these media. Synthetic examples illustrate the accuracy and efficiency of the proposed approach. A tomographic method is developed. The travel time are inverted by minimizing, in term of least-square, the misfit between the observed and calculated travel times. The solution is approached iteratively by using a singular value decomposition algorithm. The inversion stability is assured by introducing a priori constraints. Synthetics examples show the need of an acquisition geometry well conceived to take account of anisotropy. (author)
A Model of Bus Bunching under Reliability-based Passenger Arrival Patterns
Fonzone, Achille; Schmöcker, Jan-Dirk; Liu, Ronghui
2015-01-01
If bus service departure times are not completely unknown to the passengers, non-uniform passenger arrival patterns can be expected. We propose that passengers decide their arrival time at stops based on a continuous logit model that considers the risk of missing services. Expected passenger waiting times are derived in a bus system that allows also for overtaking between bus services. We then propose an algorithm to derive the dwell time of subsequent buses serving a stop in order to illustr...
[Getting qi and arrival of qi].
Liu, Nong-Yu
2014-08-01
In order to clarify the inter-relationship between getting qi and arrival of qi, the relevant theory in the Inner Canon of Yellow Emperor is re-considered, and then the relationship of the two concepts by combining with some opinions from scholars is compared and analyzed. Getting qi is the signal of acupuncture at an acupoint; also it is a sign of arrival of qi at an acupoint; what's more, it is the premise for reinforcing or reducing manipulation. The sensation of arrival of qi comes from both doctors and patients, characterized with explicit symptoms including "tight and swift", "sunken, sticky and tight", "light, loose and slow", "warm at the acupoint" or "cold at the acupoint" as well as implicit symptom including "qi moving along the meridians"; also there is the condition of qi regulation that is characterized with "paced and harmony" stomach qi. The arrival of qi could be divided into "qi moving to the needles" and "qi traveling to the diseases". The "qi moving to the needles" has similar meaning to getting qi. The "qi traveling to the diseases" is reflected as "qi arrival with efficacy" and characterized as an immediate effect or a delayed effect. There are differences between the concepts of getting qi and arrival of qi. Getting qi focuses on the importance of the doctor during acupuncture processes (differentiate the nature of qi, guard qi, manipulate qi), which also suggests the clinical significance of implicit getting qi. "Arrival of qi" emphasizes "qi arrival with efficacy", and indicates that during treatment the differences of the exterior or interior and deficit or surplus should be distinguished. For external and shallow diseases involving myofascia-related diseases, miu needling and shallow needling can achieve an immediate treatment effect; for deep, internal and deficient diseases, reinforcing or reducing manipulation should be used to achieve stomach qi, which has delayed effects but can be used as an indicator. It is believed that pulse
International Nuclear Information System (INIS)
Armour, E.A.G.; Beker, C.A.; Farina, J.E.G.
1981-01-01
P-wave phaseshifts for positron-hydrogen elastic scattering are calculated using a new adiabatic approximation in which the length of the radius vector from the proton to the positron is fixed but its direction is allowed to vary. This adiabatic approximation makes possible the full inclusion in the calculation of virtual states in which angular momentum is transferred to the target H atom. The results obtained agree qualitatively with the highly accurate results of Bhatia and co-workers (Phys. Rev.; A9:219 (1974)) and are much closer to them than the results obtained using the usual adiabatic approximation in which the radius vector from the proton to the positron is fixed. (author)
Design Principles and Algorithms for Air Traffic Arrival Scheduling
Erzberger, Heinz; Itoh, Eri
2014-01-01
This report presents design principles and algorithms for building a real-time scheduler of arrival aircraft based on a first-come-first-served (FCFS) scheduling protocol. The algorithms provide the conceptual and computational foundation for the Traffic Management Advisor (TMA) of the Center/terminal radar approach control facilities (TRACON) automation system, which comprises a set of decision support tools for managing arrival traffic at major airports in the United States. The primary objective of the scheduler is to assign arrival aircraft to a favorable landing runway and schedule them to land at times that minimize delays. A further objective of the scheduler is to allocate delays between high-altitude airspace far away from the airport and low-altitude airspace near the airport. A method of delay allocation is described that minimizes the average operating cost in the presence of errors in controlling aircraft to a specified landing time. This report is a revision of an earlier paper first presented as part of an Advisory Group for Aerospace Research and Development (AGARD) lecture series in September 1995. The authors, during vigorous discussions over the details of this paper, felt it was important to the air-trafficmanagement (ATM) community to revise and extend the original 1995 paper, providing more detail and clarity and thereby allowing future researchers to understand this foundational work as the basis for the TMA's scheduling algorithms.
International Nuclear Information System (INIS)
Mizushima, T.; Machida, K.
2010-01-01
We investigate how the vortex-vortex separation changes Majorana zero modes in the vicinity of the BCS-BEC (Bose-Einstein condensation) topological phase transition of p-wave resonant Fermi gases. By analytically and numerically solving the Bogoliubov-de Gennes equation for spinless p-wave superfluids with plural vortices, it is demonstrated that the quasiparticle tunneling between neighboring vortices gives rise to the quantum oscillation of the low-lying spectra on the scale of the Fermi wavelength in addition to the exponential splitting. This rapid oscillation, which appears in the weak-coupling regime as a consequence of quantum oscillations of quasiparticle wave functions, disappears in the vicinity of the BCS-BEC topological phase transition. This is understandable from that the wave function of the Majorana zero modes is described by the modified Bessel function in the strong-coupling regime, and thus it becomes spread over the vortex core region. Due to the exponential divergence of the modified Bessel function, the concrete realization of the Majorana zero modes near the topological phase transition requires the neighboring vortices to be separated beyond the length scale defined by the coherence length and the dimensionless coupling constant. All these behaviors are also confirmed by carrying out the full numerical diagonalization of the nonlocal Bogoliubov-de Gennes equation in a two-dimensional geometry. Furthermore, this argument is expanded into the case of three-vortex systems, where a pair of core-bound and edge-bound Majorana states survive at zero-energy state regardless of the vortex separation.
Inner core boundary topography explored with reflected and diffracted P waves
deSilva, Susini; Cormier, Vernon F.; Zheng, Yingcai
2018-03-01
The existence of topography of the inner core boundary (ICB) can affect the amplitude, phase, and coda of body waves incident on the inner core. By applying pseudospectral and boundary element methods to synthesize compressional waves interacting with the ICB, these effects are predicted and compared with waveform observations in pre-critical, critical, post-critical, and diffraction ranges of the PKiKP wave reflected from the ICB. These data sample overlapping regions of the inner core beneath the circum-Pacific belt and the Eurasian, North American, and Australian continents, but exclude large areas beneath the Pacific and Indian Oceans and the poles. In the pre-critical range, PKiKP waveforms require an upper bound of 2 km at 1-20 km wavelength for any ICB topography. Higher topography sharply reduces PKiKP amplitude and produces time-extended coda not observed in PKiKP waveforms. The existence of topography of this scale smooths over minima and zeros in the pre-critical ICB reflection coefficient predicted from standard earth models. In the range surrounding critical incidence (108-130 °), this upper bound of topography does not strongly affect the amplitude and waveform behavior of PKIKP + PKiKP at 1.5 Hz, which is relatively insensitive to 10-20 km wavelength topography height approaching 5 km. These data, however, have a strong overlap in the regions of the ICB sampled by pre-critical PKiKP that require a 2 km upper bound to topography height. In the diffracted range (>152°), topography as high as 5 km attenuates the peak amplitudes of PKIKP and PKPCdiff by similar amounts, leaving the PKPCdiff/PKIKP amplitude ratio unchanged from that predicted by a smooth ICB. The observed decay of PKPCdiff into the inner core shadow and the PKIKP-PKPCdiff differential travel time are consistent with a flattening of the outer core P velocity gradient near the ICB and iron enrichment at the bottom of the outer core.
A discontinuous Galerkin method for P-wave modeling in tilted TI media
Amler, Thomas; Alkhalifah, Tariq Ali; Hoteit, Ibrahim
2014-01-01
The acoustic approximation is an efficient alternative to the equations of elastodynamics for modeling Pwave propagation in weakly anisotropic media. We present a stable discontinuous Galerkin (DG) method for solving the acoustic approximation in tilted TI media (acoustic TI approximation). The acoustic TI approximation is considered as a modification of the equations of elastodynamics from which a modified energy is derived. The modified energy is obtained by eliminating the shear stress in the coordinates determined by the tilt angle and finding an energy for the remaining unknowns. This construction is valid if the medium is not elliptically anisotropic, a requirement frequently found in the literature. In the fully discrete setting, the modified energy is also conserved in time the presence of sharp contrasts in material parameters. By construction, the scheme can be coupled to the (fully) acoustic wave equation in the same way as the equations of elastodynamics. Hence, the number of unknowns can be reduced in acoustic regions. Our numerical examples confirm the conservation of energy in the discrete setting and the stability of the scheme.
Large teleseismic P-wave residuals observed at the Alban Hills volcano, Central Italy
Directory of Open Access Journals (Sweden)
H. Mahadeva Iyer
1994-06-01
Full Text Available We collected teleseismic waveforms from a digital microseismic network deployed by the Istituto Nazionale di Geofisica (ING in collaboration with the U.S. Geological Survey (USGS, on the Alban Hills Quaternary volcano during the 1989-1990 seismic swann. About 50 events were recorded by the network, 30 of them by at least 4 stations. We analysed the data in order to image crustal heterogeneities beneath the volcano. The results show large delay time residuals up to - 1 second for stations located on the volcano with respect to station CP9 of the National Seismic Network located about 20 km to the east, on the Apennines. This suggests that the whole area overlies a broad low-velocity region. Although the ray coverage is not very dense, we model the gross seismic structure beneath the volcano by inverting the teleseismic relative residuals with the ACH technique. The main features detected by tbc inversion are a low-velocity zone beneath the southwestern fiank of tbc volcano, and a high-velocity region beneath the center. The depth extension of these anomalous zones ranges between 5 and 16 km. The correspondence between the low-velocity region and the most recent activity of the volcano (- 0.027 Ma leads us to infer the presence of a still hot magmatic body in the crust beneath the southwestern side of the volcano, whereas the central part overlies the older and colder high-velocity volcanic roots related to the previous central activity (0.7 to 0.3 Ma.
A finite capacity queue with Markovian arrivals and two servers with group services
Directory of Open Access Journals (Sweden)
S. Chakravarthy
1994-01-01
Full Text Available In this paper we consider a finite capacity queuing system in which arrivals are governed by a Markovian arrival process. The system is attended by two exponential servers, who offer services in groups of varying sizes. The service rates may depend on the number of customers in service. Using Markov theory, we study this finite capacity queuing model in detail by obtaining numerically stable expressions for (a the steady-state queue length densities at arrivals and at arbitrary time points; (b the Laplace-Stieltjes transform of the stationary waiting time distribution of an admitted customer at points of arrivals. The stationary waiting time distribution is shown to be of phase type when the interarrival times are of phase type. Efficient algorithmic procedures for computing the steady-state queue length densities and other system performance measures are discussed. A conjecture on the nature of the mean waiting time is proposed. Some illustrative numerical examples are presented.
Kim, Seyong; Petreczky, Peter; Rothkopf, Alexander
2015-03-01
We investigate the properties of S - and P -wave bottomonium states in the vicinity of the deconfinement transition temperature. The light degrees of freedom are represented by dynamical lattice quantum chromodynamics (QCD) configurations of the HotQCD collaboration with Nf=2 +1 flavors. Bottomonium correlators are obtained from bottom quark propagators, computed in nonrelativistic QCD under the background of these gauge field configurations. The spectral functions for the 3S1 (ϒ ) and 3P1 (χb 1) channel are extracted from the Euclidean time correlators using a novel Bayesian approach in the temperature region 140 MeV ≤T ≤249 MeV and the results are contrasted to those from the standard maximum entropy method. We find that the new Bayesian approach is far superior to the maximum entropy method. It enables us to study reliably the presence or absence of the lowest state signal in the spectral function of a certain channel, even under the limitations present in the finite temperature setup. We find that χb 1 survives up to T =249 MeV , the highest temperature considered in our study, and put stringent constraints on the size of the medium modification of ϒ and χb 1 states.
Amplitude and angle of arrival measurements on a 28.56 GHz Earth-space path
Devasirvatham, D. M. J.; Hodge, D. B.
1981-01-01
The amplitude and angle of arrival measurements on an Earth-space path using the 28.56 GHz COMSTAR D3 satellite beacon are described. These measurements were made by the Ohio State University ElectroScience Laboratory during the period September 1978 to September 1979. Monthly, quarterly, and annual distributions of attenuation, angle of arrival, and variance of both these parameters are reported. During this period, fades exceeding 29 dB for .00% of the time and angle of arrival fluctuations exceeding .12 degrees for .01% of the time were observed.
T20 measurements for 1H(d searrow,γ)3He and the P-wave component of the nucleon-nucleon force
International Nuclear Information System (INIS)
Schmid, G.J.; Chasteler, R.M.; Weller, H.R.; Tilley, D.R.; Fonseca, A.C.; Lehman, D.R.
1996-01-01
Measurements of T 20 (θ lab =90 degree) for 1 H(d searrow,γ) 3 He, in the energy range E d (lab)=12.7 endash 19.8 MeV, have been compared with the results of new exact three-body Faddeev calculations using the Paris and Bonn-A nucleon-nucleon (NN) potentials. This comparison indicates a strong sensitivity of the T 20 observable to the p-wave part of the NN force. In particular, we find that the 3 P 1 component of the P-wave interaction is the dominant P-wave term affecting the value of T 20 (θ lab =90 degree) at these energies. This contrasts with the results of polarized N-D scattering studies where the 3 P 0 component has been found to dominate. cents 1996 The American Physical Society
Prediction of late/early arrivals in container terminals - A qualitative approach
Pani, C.; Vanelslander, T.; Fancello, G.; Cannas, M.
2015-01-01
Vessel arrival uncertainty in ports has become a very common problem worldwide. Although ship operators have to notify the Estimated Time of Arrival (ETA) at predetermined time intervals, they frequently have to update the latest ETA due to unforeseen circumstances. This causes a series of inconveniences that often impact on the efficiency of terminal operations, especially in the daily planning scenario. Thus, for our study we adopted a machine learning approach in order to provide a qualita...
Method for Establishing Direction of Arrival by Use of Signals of Opportunity
2017-08-29
digital converter (ADC). The analog-to-digital converter sampling process that locks the relative time features of the digital signal processing...path and is sampled by the ADC. The ADC sampling process locks the relative time properties of the individual signals components arriving at...that signal. For each wave vector, the angles that define the direction of arrival are assumed to be identical at each RF port phase center in the
NASA's ATM Technology Demonstration-1: Integrated Concept of Arrival Operations
Baxley, Brian T.; Swenson, Harry N.; Prevot, Thomas; Callantine, Todd J.
2012-01-01
This paper describes operations and procedures envisioned for NASA s Air Traffic Management (ATM) Technology Demonstration #1 (ATD-1). The ATD-1 Concept of Operations (ConOps) demonstration will integrate three NASA technologies to achieve high throughput, fuel-efficient arrival operations into busy terminal airspace. They are Traffic Management Advisor with Terminal Metering (TMA-TM) for precise time-based schedules to the runway and points within the terminal area, Controller-Managed Spacing (CMS) decision support tools for terminal controllers to better manage aircraft delay using speed control, and Flight deck Interval Management (FIM) avionics and flight crew procedures to conduct airborne spacing operations. The ATD-1 concept provides de-conflicted and efficient operations of multiple arrival streams of aircraft, passing through multiple merge points, from top-of-descent (TOD) to touchdown. It also enables aircraft to conduct Optimized Profile Descents (OPDs) from en route altitude to the runway, using primarily speed control to maintain separation and schedule. The ATD-1 project is currently addressing the challenges of integrating the three technologies, and implantation into an operational environment. Goals of the ATD-1 demonstration include increasing the throughput of high-density airports, reducing controller workload, increasing efficiency of arrival operations and the frequency of trajectory-based operations, and promoting aircraft ADS-B equipage.
Kang, S. G.; Hong, J. K.; Jin, Y. K.; Jang, U.; Niessen, F.; Baranov, B.
2017-12-01
2016 IBRV ARAON Arctic Cruise Leg-2, Expedition ARA07C was a multidisciplinary undertaking carried out in the East Siberian Sea (ESS) from August 25 to September 10, 2016. The program was conducted as a collaboration between the Korea Polar Research Institute (KOPRI), P.P. Shirshov Institute of Oceanology (IORAS), and Alfred Wegener Institute (AWI). During this expedition, the multi-channel seismic (MCS) data were acquired on the continental shelf and the upper slope of the ESS, totaling 3 lines with 660 line-kilometers. The continental shelf of ESS is one of the widest shelf seas in the world and it is believed to cover the largest area of sub-sea permafrost in the Arctic. According to the present knowledge of the glacial history of the western Arctic Ocean, it is likely that during the LGM with a sea level approximately 120 m below present, the entire shelf area of the ESS was exposed to very cold air temperatures so that thick permafrost should have formed. Indeed, in water depths shallower than 80 m, sub-bottom profiles in the ESS recorded from the shelf edge to a latitude of 74°30' N in 60 m water depth exhibited acoustic facies, suggesting that at least relicts of submarine permafrost are present. In order to identify the existence and/or non-existence of subsea permafrost in our study area, we analyze the MCS data using the Laplace domain full waveform inversion (FWI). In case of the Canadian continental shelf of the Beaufort Sea, subsea permafrost has high seismic velocity values (over 2.6 km/sec) and strong refraction events were found in the MCS shotgathers. However, in the EES our proposed P-wave velocity models derived from FWI have neither found high velocity structures (over 2.6 km/sec) nor indicate strong refraction events by subsea permafrost. Instead, in 300 m depth below sea floor higher P-wave velocity structures (1.8 2.2 km/s) than normal subsea sediment layers were found, which are interpreted as cemented strata by glaciation activities.
Does the arrival index predict physiological stress reactivity in children.
de Veld, Danielle M J; Riksen-Walraven, J Marianne; de Weerth, Carolina
2014-09-01
Knowledge about children's stress reactivity and its correlates is mostly based on one stress task, making it hard to assess the generalizability of the results. The development of an additional stress paradigm for children, that also limits stress exposure and test time, could greatly advance this field of research. Research in adults may provide a starting point for the development of such an additional stress paradigm, as changes in salivary cortisol and alpha-amylase (sAA) over a 1-h pre-stress period in the laboratory correlated strongly with subsequent reactivity to stress task (Balodis et al., 2010, Psychoneuroendocrinology 35:1363-73). The present study examined whether such strong correlations could be replicated in 9- to 11-year-old children. Cortisol and sAA samples were collected from 158 children (83 girls) during a 2.5-h visit to the laboratory. This visit included a 1-h pre-stress period in which children performed some non-stressful tasks and relaxed before taking part in a psychosocial stress task (TSST-C). A higher cortisol arrival index was significantly and weakly correlated with a higher AUCg but unrelated to cortisol reactivity to the stressor. A higher sAA arrival index was significantly and moderately related to lower stress reactivity and to a lower AUCi. Children's personality and emotion regulation variables were unrelated to the cortisol and sAA arrival indices. The results of this study do not provide a basis for the development of an additional stress paradigm for children. Further replications in children and adults are needed to clarify the potential meaning of an arrival index.
FORECASTING TOURIST ARRIVALS TO LANGKAWI ISLAND MALAYSIA
Directory of Open Access Journals (Sweden)
Kamarul Ariffin MANSOR
2015-06-01
Full Text Available Tourism is the act of travelling for a person or group of people from their own locality to a specific destination in a short term or long term period either for leisure or business purposes. Tourism is an important sector in the Malaysian economy where tourism development will lead to the positive economic development of the country and in general improve the quality of life for all citizens. Therefore, forecasting tourist arrivals with high accuracy becomes important since it may ensure the development and the readiness of all tourism related industries such as hotels, transportation, food and services industries and their best shape. This study focuses on tourist arrivals in Langkawi Island as one of the major tourist attractions situated in the northerly region of Peninsular Malaysia. Importantly, this paper attempts to measure and compare the performance of forecasting with Exponential Smoothing, ARIMA and ARFIMA models using the R software package.
FORECASTING TOURIST ARRIVALS TO LANGKAWI ISLAND MALAYSIA
Kamarul Ariffin MANSOR; Wan Irham ISHAK
2015-01-01
Tourism is the act of travelling for a person or group of people from their own locality to a specific destination in a short term or long term period either for leisure or business purposes. Tourism is an important sector in the Malaysian economy where tourism development will lead to the positive economic development of the country and in general improve the quality of life for all citizens. Therefore, forecasting tourist arrivals with high accuracy becomes important since it may ensure t...
The first American magnet has arrived!
2003-01-01
On 21 January the first US-built LHC magnet arrived at CERN, after a journey of 6000 km by land and sea, an event hailed on both sides of the Atlantic. This 10-m long, 4.7-tonne dipole magnet was manufactured over a period of nine months by Brookhaven National Laboratory (BNL). Single-aperture magnets of this type will be installed on either side of the ALICE and LHCb experiments and will deviate the beams in order to provoke their interaction and subsequent separation. Brookhaven will be supplying 19 other dipoles for the insertion regions, including four of the same type as the one which has just arrived. «These magnets are based on a technology developed by Brookhaven Laboratory for its own RHIC accelerator,» explains Ranko Ostojic. LHC Project Leader Lyn Evans adds «our Brookhaven colleagues have done a fantastic job in completing the USA's first superconducting magnet for the LHC to specification and on schedule. Other deliveries will shortly be arriving from Brookhaven but also from Fermilab and the ...
Lee, Kwang Jin; Kim, Kihong
2011-10-10
We study theoretically the propagation and the Anderson localization of p-polarized electromagnetic waves incident obliquely on randomly stratified dielectric media with weak uncorrelated Gaussian disorder. Using the invariant imbedding method, we calculate the localization length and the disorder-averaged transmittance in a numerically precise manner. We find that the localization length takes an extremely large maximum value at some critical incident angle, which we call the generalized Brewster angle. The disorder-averaged transmittance also takes a maximum very close to one at the same incident angle. Even in the presence of an arbitrarily weak disorder, the generalized Brewster angle is found to be substantially different from the ordinary Brewster angle in uniform media. It is a rapidly increasing function of the average dielectric permittivity and approaches 90° when the average relative dielectric permittivity is slightly larger than two. We make a remarkable observation that the dependence of the generalized Brewster angle on the average dielectric permittivity is universal in the sense that it is independent of the strength of disorder. We also find, surprisingly, that when the average relative dielectric permittivity is less than one and the incident angle is larger than the generalized Brewster angle, both the localization length and the disorder-averaged transmittance increase substantially as the strength of disorder increases in a wide range of the disorder parameter. In other words, the Anderson localization of incident p waves can be weakened by disorder in a certain parameter regime.
Hugdal, Henning G.; Sudbø, Asle
2018-01-01
We study the superconducting order in a two-dimensional square lattice Hubbard model with weak repulsive interactions, subject to a Zeeman field and weak Rashba spin-orbit interactions. Diagonalizing the noninteracting Hamiltonian leads to two separate bands, and by deriving an effective low-energy interaction we find the mean field gap equations for the superconducting order parameter on the bands. Solving the gap equations just below the critical temperature, we find that superconductivity is caused by Kohn-Luttinger-type interaction, while the pairing symmetry of the bands is indirectly affected by the spin-orbit coupling. The dominating attractive momentum channel of the Kohn-Luttinger term depends on the filling fraction n of the system, and it is therefore possible to change the momentum dependence of the order parameter by tuning n . Moreover, n also determines which band has the highest critical temperature. Rotating the magnetic field changes the momentum dependence from states that for small momenta reduce to a chiral px±i py type state for out-of-plane fields, to a nodal p -wave-type state for purely in-plane fields.
Replacement policy in a system under shocks following a Markovian arrival process
International Nuclear Information System (INIS)
Montoro-Cazorla, Delia; Perez-Ocon, Rafael; Carmen Segovia, Maria del
2009-01-01
We present a system subject to shocks that arrive following a Markovian arrival process. The system is minimally repaired. It is replaced when a certain number of shocks arrive. A general model where the replacements are governed by a discrete phase-type distribution is studied. For this system, the Markov process governing the system is constructed, and the interarrival times between replacements and the number of replacements are calculated. A special case of this system is when it can stand a prefixed number of shocks. For this new system, the same performance measures are calculated. The systems are considered in transient and stationary regime
Replacement policy in a system under shocks following a Markovian arrival process
Energy Technology Data Exchange (ETDEWEB)
Montoro-Cazorla, Delia [Department of Statistics and Operational Research, University of Jaen (Spain); Perez-Ocon, Rafael [Department of Statistics and Operational Research, University of Granada, Granada (Spain)], E-mail: rperezo@ugr.es; Carmen Segovia, Maria del [Departamento de Estadistica e I.O., University of Granada, Granada (Spain)
2009-02-15
We present a system subject to shocks that arrive following a Markovian arrival process. The system is minimally repaired. It is replaced when a certain number of shocks arrive. A general model where the replacements are governed by a discrete phase-type distribution is studied. For this system, the Markov process governing the system is constructed, and the interarrival times between replacements and the number of replacements are calculated. A special case of this system is when it can stand a prefixed number of shocks. For this new system, the same performance measures are calculated. The systems are considered in transient and stationary regime.
GMTI Direction of Arrival Measurements from Multiple Phase Centers.
Energy Technology Data Exchange (ETDEWEB)
Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bickel, Douglas L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2015-03-01
Ground Moving Target Indicator (GMTI) radar attempts to detect and locate targets with unknown motion. Very slow-moving targets are difficult to locate in the presence of surrounding clutter. This necessitates multiple antenna phase centers (or equivalent) to offer independent Direction of Arrival (DOA) measurements. DOA accuracy and precision generally remains dependent on target Signal-to-Noise Ratio (SNR), Clutter-toNoise Ratio (CNR), scene topography, interfering signals, and a number of antenna parameters. This is true even for adaptive techniques like Space-Time-AdaptiveProcessing (STAP) algorithms.
Post-arrival health screening in Karen refugees in Australia.
Paxton, Georgia A; Sangster, Katrina J; Maxwell, Ellen L; McBride, Catherine R J; Drewe, Ross H
2012-01-01
To document the prevalence of nutritional deficiencies, infectious diseases and susceptibility to vaccine preventable diseases in Karen refugees in Australia. Retrospective audit of pathology results. Community based cohort in Melbourne over the period July 2006-October 2009. 1136 Karen refugee children and adults, representing almost complete local area settlement and 48% of total Victorian Karen humanitarian intake for the time period. Prevalence of positive test results for refugee health screening, with breakdown by age group (Karen refugees have high rates of nutritional deficiencies and infectious diseases and may be susceptible to vaccine preventable diseases. These data support the need for post-arrival health screening and accessible, funded catch-up immunisation.
Directory of Open Access Journals (Sweden)
Emily C. O'Brien
2011-01-01
Full Text Available Background. Recent studies report that acute stroke patients who present to the hospital on weekends have higher rates of 28-day mortality than similar patients who arrive during the week. However, how this association is related to clinical presentation and stroke type has not been systematically investigated. Methods and Results. We examined the association between day of arrival and 28-day mortality in 929 validated stroke events in the ARIC cohort from 1987–2004. Weekend arrival was defined as any arrival time from midnight Friday until midnight Sunday. Mortality was defined as all-cause fatal events from the day of arrival through the 28th day of followup. The presence or absence of thirteen stroke signs and symptoms were obtained through medical record review for each event. Binomial logistic regression was used to estimate odds ratios and 95% confidence intervals (OR; 95% CI for the association between weekend arrival and 28-day mortality for all stroke events and for stroke subtypes. The overall risk of 28-day mortality was 9.6% for weekday strokes and 10.1% for weekend strokes. In models controlling for patient demographics, clinical risk factors, and event year, weekend arrival was not associated with 28-day mortality (0.87; 0.51, 1.50. When stratified by stroke type, weekend arrival was not associated with increased odds of mortality for ischemic (1.17, 0.62, 2.23 or hemorrhagic (0.37; 0.11, 1.26 stroke patients. Conclusions. Presence or absence of thirteen signs and symptoms was similar for weekday patients and weekend patients when stratified by stroke type. Weekend arrival was not associated with 28-day all-cause mortality or differences in symptom presentation for strokes in this cohort.
Automated Conflict Resolution, Arrival Management and Weather Avoidance for ATM
Erzberger, H.; Lauderdale, Todd A.; Chu, Yung-Cheng
2010-01-01
The paper describes a unified solution to three types of separation assurance problems that occur in en-route airspace: separation conflicts, arrival sequencing, and weather-cell avoidance. Algorithms for solving these problems play a key role in the design of future air traffic management systems such as NextGen. Because these problems can arise simultaneously in any combination, it is necessary to develop integrated algorithms for solving them. A unified and comprehensive solution to these problems provides the foundation for a future air traffic management system that requires a high level of automation in separation assurance. The paper describes the three algorithms developed for solving each problem and then shows how they are used sequentially to solve any combination of these problems. The first algorithm resolves loss-of-separation conflicts and is an evolution of an algorithm described in an earlier paper. The new version generates multiple resolutions for each conflict and then selects the one giving the least delay. Two new algorithms, one for sequencing and merging of arrival traffic, referred to as the Arrival Manager, and the other for weather-cell avoidance are the major focus of the paper. Because these three problems constitute a substantial fraction of the workload of en-route controllers, integrated algorithms to solve them is a basic requirement for automated separation assurance. The paper also reviews the Advanced Airspace Concept, a proposed design for a ground-based system that postulates redundant systems for separation assurance in order to achieve both high levels of safety and airspace capacity. It is proposed that automated separation assurance be introduced operationally in several steps, each step reducing controller workload further while increasing airspace capacity. A fast time simulation was used to determine performance statistics of the algorithm at up to 3 times current traffic levels.
Macmynowski, Dena P.; Root, Terry L.
2007-05-01
The intra- and inter-season complexity of bird migration has received limited attention in climatic change research. Our phenological analysis of 22 species collected in Chicago, USA, (1979 2002) evaluates the relationship between multi-scalar climate variables and differences (1) in arrival timing between sexes, (2) in arrival distributions among species, and (3) between spring and fall migration. The early migratory period for earliest arriving species (i.e., short-distance migrants) and earliest arriving individuals of a species (i.e., males) most frequently correlate with climate variables. Compared to long-distance migrant species, four times as many short-distance migrants correlate with spring temperature, while 8 of 11 (73%) of long-distance migrant species’ arrival is correlated with the North Atlantic Oscillation (NAO). While migratory phenology has been correlated with NAO in Europe, we believe that this is the first documentation of a significant association in North America. Geographically proximate conditions apparently influence migratory timing for short-distance migrants while continental-scale climate (e.g., NAO) seemingly influences the phenology of Neotropical migrants. The preponderance of climate correlations is with the early migratory period, not the median of arrival, suggesting that early spring conditions constrain the onset or rate of migration for some species. The seasonal arrival distribution provides considerable information about migratory passage beyond what is apparent from statistical analyses of phenology. A relationship between climate and fall phenology is not detected at this location. Analysis of the within-season complexity of migration, including multiple metrics of arrival, is essential to detect species’ responses to changing climate as well as evaluate the underlying biological mechanisms.
A key component of the Globe arrives
2003-01-01
The first component of the Palais de l'Equilibre arrived at CERN last week. Renamed the Globe of Innovation, this elegant wooden sphere will be inaugurated in October 2004. The convoy transporting the first component of the Palais de l'Equilibre, the keystone of the famous wooden globe, arrived at CERN on the night of 28th August in the middle of a violent storm and dramatic flashes of lightning. Erected in Neuchâtel last year for the EXPO.02 exhibition, the Palais de l'Equilibre was a gift to the Laboratory from the Swiss Confederation (see Bulletin 25/2003). The gift of the structure and 4 million Swiss francs, together with help from the Swiss army for the reassembly work, received the final approval of the Swiss Federal Council on 20th August 2003. Renamed the Globe of Innovation, the 27-metre-high sphere measuring 40 metres in diameter will house the Laboratory's new exhibition centre in 2005. The keystone, known as the "central vertex", is a crown measuring 6.5 m in diameter and 4.5 m high, located a...
First SCT Barrel arrives at CERN
Apsimon, R
Mid-January saw the arrival at CERN of Barrel #3, the first of four SCT barrels. The barrels are formed as low-mass cylinders of carbon fibre skins on a honeycomb carbon core. They are manufactured in industry and then have all the final precision supports added and the final geometric metrology carried out at Geneva University. Barrel #3, complete with its 384 silicon detector modules, arrived by road from Oxford University in England where the modules were mounted using a purpose-built robot. The modules had been selected from the output of all four barrel module building clusters (in Japan, Scandinavia, USA and the UK). Since Barrel #3 will be exposed to high radiation levels within the tracker volume, these modules, representing over half a million readout channels, have been extensively tested at their operational temperature of around -25 degrees Celcius and at voltages of up to 500V. The dangers of shipping such a fragile component of ATLAS were apparent to all and considerable attention was focused...
LHCb Calorimeter modules arrive at CERN
2002-01-01
Two of the three components of the LHCb Calorimeter system have started to arrive from Russia. Members of the LHCb Calorimeter group with the ECAL and HCAL modules that have just arrived at CERN. The first two of the 56 Hadron Calorimeter (HCAL) modules and 1200 of the 3300 modules of the Electromagnetic Calorimeter (ECAL) have reached CERN from Russia. The third part of the system, the Preshower detector, is still being prepared in Russia. The calorimeter system identifies and triggers on high-energy particles, namely electrons, hadrons and photons by measuring their positions and energies. The HCAL is going to be a pure trigger device. The ECAL will also be used in the triggering, but in addition it will reconstruct neutral pions and photons from B meson decays. One of the major aims of the LHCb experiment is to study CP violation through B meson decays including Bs mesons with high statistics in different decay modes. CP violation (violation of charge and parity) is necessary to explain why the Universe...
Quasi-Birth-and-Death Processes with Rational Arrival Process Components
DEFF Research Database (Denmark)
Bean, Nigel G.; Nielsen, Bo Friis
2010-01-01
This paper introduces the concept of a Quasi-Birth-and-Death process (QBD) with Rational Arrival Process (RAP) components. We use the physical interpretation of the prediction process of the RAP, developed by Asmussen and Bladt, and develop an analysis that parallels the analysis of a traditional...... QBD. Further, we present an algorithm for the numerical evaluation of the matrix G. As an example, we consider two queues where the arrival process and the sequence of service times are taken from two dependent RAPs, that are not Markovian Arrival Processes......This paper introduces the concept of a Quasi-Birth-and-Death process (QBD) with Rational Arrival Process (RAP) components. We use the physical interpretation of the prediction process of the RAP, developed by Asmussen and Bladt, and develop an analysis that parallels the analysis of a traditional...
AE source location by neural networks with arrival time profiles
Czech Academy of Sciences Publication Activity Database
Chlada, Milan; Blaháček, Michal; Převorovský, Zdeněk
2009-01-01
Roč. 19, č. 2 (2009), s. 4-4 ISSN 1213-3825. [NDT in PROGRESS. 12.11.2009-14.11.2009, Praha] R&D Projects: GA ČR GA101/07/1518; GA ČR GA106/07/1393 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustic emission * source location * artificial neural networks Subject RIV: BI - Acoustics www.cndt.cz
Original Research Factors associated with hospital arrival time after ...
African Journals Online (AJOL)
This work is licensed under the Creative Commons Attribution 4.0 International License. .... Employment status ... Hospital based study bias which favours more .... confidence interval). P-value. Late. (> 3 hours). Early. (≤ 3 hours). Gender.
A Contract That Manages Itself: The Time Has Arrived
2015-02-01
technology inspires contracting. The Smart Contract The paradigm of a contract as a static document is about to change. The days of a contract being read...efficiency is of paramount importance in order for an organization to perform its mission. The Smart Contract as an Object In discussions about...the contract object ( smart contract ) exists, the contract will be able to interact with other objects. That will enable the contract to know how
Timing the arrival at 2340m altitude for aerobic performance
DEFF Research Database (Denmark)
Schuler, B; Thomsen, JJ; Gassmann, M
2007-01-01
This study tested the hypothesis that maximal oxygen uptake (VO2max) and performance increase upon altitude acclimatization at moderate altitude. Eight elite cyclists were studied at sea level, and after 1 (Day 1), 7 (Day 7), 14 (Day 14) and 21 (Day 21) days of exposure to 2340 m. Capillary blood...
STRONG FIELD EFFECTS ON PULSAR ARRIVAL TIMES: GENERAL ORIENTATIONS
International Nuclear Information System (INIS)
Wang Yan; Creighton, Teviet; Price, Richard H.; Jenet, Frederick A.
2009-01-01
A pulsar beam passing close to a black hole can provide a probe of very strong gravitational fields even if the pulsar itself is not in a strong field region. In the case that the spin of the hole can be ignored, we have previously shown that all strong field effects on the beam can be understood in terms of two 'universal' functions: F(φ in ) and T(φ in ) of the angle of beam emission φ in ; these functions are universal in that they depend only on a single parameter, the pulsar/black hole distance from which the beam is emitted. Here we apply this formalism to general pulsar-hole-observer geometries, with arbitrary alignment of the pulsar spin axis and arbitrary pulsar beam direction and angular width. We show that the analysis of the observational problem has two distinct elements: (1) the computation of the location and trajectory of an observer-dependent 'keyhole' direction of emission in which a signal can be received by the observer; and (2) the determination of an annulus that represents the set of directions containing beam energy. Examples of each are given along with an example of a specific observational scenario.
Performance of Real-time Earthquake Information System in Japan
Nakamura, H.; Horiuchi, S.; Wu, C.; Yamamoto, S.
2008-12-01
Horiuchi et al. (2005) developed a real-time earthquake information system (REIS) using Hi-net, a densely deployed nationwide seismic network, which consists of about 800 stations operated by NIED, Japan. REIS determines hypocenter locations and earthquake magnitudes automatically within a few seconds after P waves arrive at the closest station and calculates focal mechanisms within about 15 seconds. Obtained hypocenter parameters are transferred immediately by using XML format to a computer in Japan Meteorological Agency (JMA), who started the service of EEW to special users in June 2005. JMA also developed EEW using 200 stations. The results by the two systems are merged. Among all the first issued EEW reports by both systems, REIS information accounts for about 80 percent. This study examines the rapidity and credibility of REIS by analyzing the 4050 earthquakes which occurred around the Japan Islands since 2005 with magnitude larger than 3.0. REIS re-determines hypocenter parameters every one second according to the revision of waveform data. Here, we discuss only about the results by the first reports. On rapidness, our results show that about 44 percent of the first reports are issued within 5 seconds after the P waves arrives at the closest stations. Note that this 5-second time window includes time delay due to data package and transmission delay of about 2 seconds. REIS waits till two stations detect P waves for events in the network but four stations outside the network so as to get reliable solutions. For earthquakes with hypocentral distance less than 100km, 55 percent of earthquakes are warned in 5 seconds and 87 percent are warned in 10 seconds. Most of events having long time delay are small and triggered by S wave arrivals. About 80 percent of events have difference in epicenter distances less than 20km relative to JMA manually determined locations. Because of the existence of large lateral heterogeneity in seismic velocity, the difference depends
Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media
Pestana, Reynam C; Ursin, Bjø rn; Stoffa, Paul L
2012-01-01
In isotropic media, we use the scalar acoustic wave equation to perform reverse time migration (RTM) of the recorded pressure wavefield data. In anisotropic media, P- and SV-waves are coupled, and the elastic wave equation should be used for RTM. For computational efficiency, a pseudo-acoustic wave equation is often used. This may be solved using a coupled system of second-order partial differential equations. We solve these using a pseudo spectral method and the rapid expansion method (REM) for the explicit time marching. This method generates a degenerate SV-wave in addition to the P-wave arrivals of interest. To avoid this problem, the elastic wave equation for vertical transversely isotropic (VTI) media can be split into separate wave equations for P- and SV-waves. These separate wave equations are stable, and they can be effectively used to model and migrate seismic data in VTI media where |ε- δ| is small. The artifact for the SV-wave has also been removed. The independent pseudo-differential wave equations can be solved one for each mode using the pseudo spectral method for the spatial derivatives and the REM for the explicit time advance of the wavefield. We show numerically stable and high-resolution modeling and RTM results for the pure P-wave mode in VTI media. © 2012 Sinopec Geophysical Research Institute.
Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media
Pestana, Reynam C
2012-04-24
In isotropic media, we use the scalar acoustic wave equation to perform reverse time migration (RTM) of the recorded pressure wavefield data. In anisotropic media, P- and SV-waves are coupled, and the elastic wave equation should be used for RTM. For computational efficiency, a pseudo-acoustic wave equation is often used. This may be solved using a coupled system of second-order partial differential equations. We solve these using a pseudo spectral method and the rapid expansion method (REM) for the explicit time marching. This method generates a degenerate SV-wave in addition to the P-wave arrivals of interest. To avoid this problem, the elastic wave equation for vertical transversely isotropic (VTI) media can be split into separate wave equations for P- and SV-waves. These separate wave equations are stable, and they can be effectively used to model and migrate seismic data in VTI media where |ε- δ| is small. The artifact for the SV-wave has also been removed. The independent pseudo-differential wave equations can be solved one for each mode using the pseudo spectral method for the spatial derivatives and the REM for the explicit time advance of the wavefield. We show numerically stable and high-resolution modeling and RTM results for the pure P-wave mode in VTI media. © 2012 Sinopec Geophysical Research Institute.
Energy Technology Data Exchange (ETDEWEB)
Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh
2007-06-06
Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (V), all S-wave measurements are presented that were performed in Borehole C4996 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.
Energy Technology Data Exchange (ETDEWEB)
Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh
2007-06-06
Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (VI), all S-wave measurements are presented that were performed in Borehole C4997 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.
Scholz, John-Robert; Barruol, Guilhem; Fontaine, Fabrice R.; Sigloch, Karin
2016-04-01
sensor orientations. In this study, we analyzed particle motions of P-waves (P-pol) and of Rayleigh waves (R-pol) to quantify the orientation of each of the 57 OBS. We performed 213 polarization measurements based on 35 earthquakes for P-pol, and 381 polarization measurements based on 48 earthquakes for R-pol. This allowed us to successfully determine the North/South orientations for 40 out of 57 OBS: 13 stations were devoid of usable data and 4 stations were too noisy. From twice the standard deviation (95% confidence interval), we estimate the errors between 1° and 20°.
Bai, Y.; Ai, Y.; Jiang, M.; He, Y.; Chen, Q.
2017-12-01
The deep structure of the southeastern Tibetan plateau is of great scientific importance to a better understanding of the India-Eurasia collision as well as the evolution of the magnificent Tibetan plateau. In this study, we collected 566 permanent and temporary seismic stations deployed in SE Tibet, with a total of 77853 high quality P-wave receiver functions been extracted by maximum entropy deconvolution method. On the basis of the Common Conversion Point (CCP) stacking technique, we mapped the topography of the 410km and 660km discontinuities (hereinafter called the `410' and the `660'), and further investigated the lateral variation of the mantle transition zone (MTZ) thickness beneath this region. The background velocity model deduced from H-κ stacking results and a previous body-wave tomographic research was applied for the correction of the crustal and upper mantle heterogeneities beneath SE Tibet for CCP stacking. Our results reveal two significantly thickened MTZ anomalies aligned nearly in the south-north direction. The magnitude of both anomalies are 30km above the global average of 250km. The southern anomaly located beneath the Dianzhong sub-block and the Indo-China block is characterized by a slightly deeper `410' and a greater-than-normal `660', while the northern anomaly beneath western Sichuan has an uplifted `410' and a depressed `660'. Combining with previous studies in the adjacent region, we suggest that slab break-off may occurred during the eastward subduction of the Burma plate, with the lower part of the cold slab penetrated into the MTZ and stagnated at the bottom of the `660' which may cause the southern anomaly in our receiver function images. The origin of the Tengchong volcano is probably connected to the upwelling of the asthenospheric material caused by the slab break-off or to the ascending of the hot and wet material triggered by the dehydration of stagnant slab in the MTZ. The anomaly in the north, on the other hand, might be
The Stardust spacecraft arrives at KSC
1998-01-01
After arrival at the Shuttle Landing Facility in the early morning hours, the crated Stardust spacecraft waits to be unloaded from the aircraft. Built by Lockheed Martin Astronautics near Denver, Colo., for the Jet Propulsion Laboratory (JPL) NASA, the spacecraft Stardust will use a unique medium called aerogel to capture comet particles flying off the nucleus of comet Wild 2 in January 2004, plus collect interstellar dust for later analysis. Stardust will be launched aboard a Boeing Delta 7426 rocket from Complex 17, Cape Canaveral Air Station, targeted for Feb. 6, 1999. The collected samples will return to Earth in a re- entry capsule to be jettisoned from Stardust as it swings by in January 2006.
Reuter; Ward; Blanckenhorn
1998-12-07
In most previous work on the yellow dung fly Scathophaga stercoraria (L.), as on other species, adaptive explanations have been sought for male behaviour whereas female behaviour has not been examined in similar detail. Here, the arrival of females at the mating site, fresh cattle droppings, is investigated. While almost all males are present shortly after pat deposition females arrive at a low, decreasing rate over an interval of about 5 hours. We propose that the distribution of female arrival times represents a mixed Evolutionarily Stable Strategy (ESS), formed by different trade-offs between costs and benefits of early and late arrival. Early arrival could be favoured by advantages due to better conditions for oviposition, faster egg development of reduced larval competition. Late arrival could be favoured by negative effects on females of male-male competition being weaker later after deposition. Computer simulations with distributions of arrival times deviating from the natural one were performed to "measure" the costs for females arriving at different times. These costs were compared with estimated benefits corresponding to the females' arrival times. This procedure revealed that females coming to the pat later in a population of females arriving shortly after deposition would be favoured. In a population arriving according to a uniform distribution, early females would have fitness advantages. Thus, evolution should lead to an intermediate distribution of arrival times, as in nature, i.e. female arrival behaviour is probably adaptive. The simulations also revealed that the intensity of sexual selection though male-male competition is highest with the natural pattern of female arrival. Therefore, natural selection generating this pattern amplifies the intensity of male-male interaction as a by-product. Copyright 1998 Academic Press
International Nuclear Information System (INIS)
Gastaldi, U.; Ahmad, S.; Amsler, C.
1984-01-01
This chapter discusses an experiment designed to study the general features of p - p interactions at rest, to extend work done in the spectroscopy of light mesons produced in p - p annihilations at rest, and to search with high sensitivity for gluonium, qq - qq baryonium structures and NN states bound by strong interactions. The effect of using a gas target and a large acceptance X-ray detector is examined. The rate and the signature of antiprotons stopping in the gas target are investigated. Topics covered include the protonium cascade and spectroscopy; a comparison of S-wave and P-wave p - p annihilations at rest; - p stop and the formation of p - p atoms; the x-ray detector (projection chamber, electronics, tests); and examples of estimations of signal and background (protonium spectroscopy, search of resonances in P-wave annihilations, search of resonances in S-wave annihilations). The distinctive features of the ASTERIX experiment are the use of a gaseous H 2 target instead of a conventional liquid H 2 one; an X-ray detector of large overall detection efficiency, low energy threshold and low background rate that enables identification of P-wave and S-wave annihilation events from 2P and 1S levels of protonium; a detection system for the products of p - p annihilations; and a trigger system that enables filtration of the acquisition of events by means of two independent chains of processors working in parallel
Simple approximations for the batch-arrival MX/G/1 queue
van Ommeren, Jan C.W.
1990-01-01
In this paper we consider the MX/G/I queueing system with batch arrivals. We give simple approximations for the waiting-time probabilities of individual customers. These approximations are checked numerically and they are found to perform very well for a wide variety of batch-size and service-timed
A descriptive study on public transport user behaviour from Live Bus Arrivals
Dell’Amico, M.; Hadjidimitriou, S.; Kaparias, I.
2014-01-01
In order to offer public transport that meet citizens’ needs for transport and further increase the use of bus services, Public Authorities need to analyse and understand travellers behaviour. Automatic Vehicle Location (AVL) data provide information on the observed time of arrival and departure of a bus at each stop. These data are fed into an algorithm to provide information to users on the expected time of arrival at the bus stop by an on-line service. In the city of London this service is...
Tourist Arrivals to Sabah by Using Fuzzy Forecasting
Directory of Open Access Journals (Sweden)
Tarmudi Zamali
2014-01-01
Full Text Available The aim of this paper is to investigate the existing tourist trend arrival in Sabah based on fuzzy approach. It focuses on the latest 12 years (2002 – 2013 visitors arrival based on their nationality for forecasting purposes. Based on Sabah Tourism Board’s data, the tourist arrival continue to grow annually but with an inconsistent number of arrival. This can be seen from the trend of tourist arrival from 2011 to 2012. There is an increase in the number of arrival but only at 1.1 % compared to the other years which are in the rank of 10 – 18% increase in number of arrival per year. Therefore, the purpose of this study is to predict the number of tourist arrival to Sabah. The study employs the modification of Fuzzy Delphi Method (FDM and utilizes the flexibility of triangular fuzzy numbers (TFNs as well as fuzzy averaging to deal with the yearly inconsistency numbers of visitor’s arrival. Then, the trio levels of alpha (α-cut was used via linguistic variables to assess the confidence of decision made and to overcome the uncertainty of the input data sets. The analysis was carried out using fully data sets obtained from the official website of Sabah tourism board. Results show that our proposed forecasting approach offers a new dimension technique as compared to the traditional statistical method. It also derived more confident decision and precision forecast for Sabah tourism authority planning purposes.
Forecasting tourist arrivals to balearic islands using genetic programming
Directory of Open Access Journals (Sweden)
Rosselló-Nadal, Jaume
2007-01-01
Full Text Available Traditionally, univariate time-series models have largely dominated forecasting for international tourism demand. In this paper, the ability of a Genetic Program (GP to predict monthly tourist arrivals from UK and Germany to Balearic Islands (Spain is explored. GP has already been employed satisfactorily in different scientific areas, including economics. The technique shows different advantages regarding to other forecasting methods. Firstly, it does not assume a priori a rigid functional form of the model. Secondly, it is more robust and easy-to-use than other non-parametric methods. Finally, it provides explicitly a mathematical equation which allows a simple ad hoc interpretation of the results. Comparing the performance of the proposed technique against other method commonly used in tourism forecasting (no-change model, Moving Average and ARIMA, the empirical results reveal that GP can be a valuable tool in this field.
Airborne Precision Spacing (APS) Dependent Parallel Arrivals (DPA)
Smith, Colin L.
2012-01-01
The Airborne Precision Spacing (APS) team at the NASA Langley Research Center (LaRC) has been developing a concept of operations to extend the current APS concept to support dependent approaches to parallel or converging runways along with the required pilot and controller procedures and pilot interfaces. A staggered operations capability for the Airborne Spacing for Terminal Arrival Routes (ASTAR) tool was developed and designated as ASTAR10. ASTAR10 has reached a sufficient level of maturity to be validated and tested through a fast-time simulation. The purpose of the experiment was to identify and resolve any remaining issues in the ASTAR10 algorithm, as well as put the concept of operations through a practical test.
Predictors of early arrival at the emergency department in acute ischaemic stroke.
LENUS (Irish Health Repository)
Curran, C
2012-01-31
BACKGROUND: A requirement of an effective acute stroke service is the early arrival of patients to the hospital emergency department (ED). This will allow the possible use of thrombolytic therapy or other acute interventions within a limited time window. AIMS: We investigated the predictors of early arrival in a single hospital serving a mixed urban and rural catchment area. METHODS: A retrospective review of all case notes for 1 year was performed. RESULTS: Of 105 acute strokes, 91 were cerebral infarcts and a total of 71 cases presenting initially to the ED had timing available for analysis. 39.4% presented within 3 h, and 12.7% were potentially suitable for thrombolysis. Those living closer to the hospital were not more likely to arrive within 3 h (Z = -0.411, p = 0.68). Presenting directly to the hospital by emergency services (or private transport) was significantly associated with early arrival in a univariate comparison (p < 0.001), and in a multivariate model. CONCLUSION: The only independent predictor of early arrival to the ED is direct presentation. Improved public education of the importance of recognition of stroke symptoms and rapid contact with the emergency services will improve the early attendance following acute stroke, allowing increased use of acute stroke treatments.
Directory of Open Access Journals (Sweden)
Ben L Phillips
Full Text Available Pathogen spread can cause population declines and even species extinctions. Nonetheless, in the absence of tailored monitoring schemes, documenting pathogen spread can be difficult. In the case of worldwide amphibian declines the best present understanding is that the chytrid fungus Batrachochytrium dendrobatidis (Bd has recently spread, causing amphibian declines and extinction in the process. However, good evidence demonstrating pathogen arrival followed by amphibian decline is rare, and analysis of putative evidence is often inadequate. Here we attempt to examine the relationship between Bd arrival and amphibian decline across north-eastern Australia, using sites where a wave-like pattern of amphibian decline was first noticed and at which intensive research has since been conducted. We develop an analytical framework that allows rigorous estimation of pathogen arrival date, which can then be used to test for a correlation between the time of pathogen arrival and amphibian decline across sites. Our results show that, with the current dataset, the earliest possible arrival date of Bd in north-eastern Australia is completely unresolved; Bd could have arrived immediately before sampling commenced or may have arrived thousands of years earlier, the present data simply cannot say. The currently available data are thus insufficient to assess the link between timing of pathogen arrival and population decline in this part of the world. This data insufficiency is surprising given that there have been decades of research on chytridiomycosis in Australia and that there is a general belief that the link between Bd arrival and population decline is well resolved in this region. The lack of data on Bd arrival currently acts as a major impediment to determining the role of environmental factors in driving the global amphibian declines, and should be a major focus of future research.
Graeber, Frank M.; Asch, Günter
1999-09-01
The PISCO'94 (Proyecto de Investigatión Sismológica de la Cordillera Occidental, 1994) seismological network of 31 digital broad band and short-period three-component seismometers was deployed in northern Chile between the Coastal Cordillera and the Western Cordillera. More than 5300 local seismic events were observed in a 100 day period. A subset of high-quality P and S arrival time data was used to invert simultaneously for hypocenters and velocity structure. Additional data from two other networks in the region could be included. The velocity models show a number of prominent anomalies, outlining an extremely thickened crust (about 70 km) beneath the forearc region, an anomalous crustal structure beneath the recent magmatic arc (Western Cordillera) characterized by very low velocities, and a high-velocity slab. A region of an increased Vp/Vs ratio has been found directly above the Wadati-Benioff zone, which might be caused by hydration processes. A zone of lower than average velocities and a high Vp/Vs ratio might correspond to the asthenospheric wedge. The upper edge of the Wadati-Benioff zone is sharply defined by intermediate depth hypocenters, while evidence for a double seismic zone can hardly be seen. Crustal events between the Precordillera and the Western Cordillera have been observed for the first time and are mainly located in the vicinity of the Salar de Atacama down to depths of about 40 km.
7 CFR 319.8-4 - Notice of arrival.
2010-01-01
... for the Plant Protection and Quarantine Programs, a notice of such arrival, on a form provided for... 7 Agriculture 5 2010-01-01 2010-01-01 false Notice of arrival. 319.8-4 Section 319.8-4 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE...
7 CFR 319.75-6 - Arrival notification.
2010-01-01
... Plant Protection and Quarantine of the arrival by such means as a manifest, Customs entry document... 7 Agriculture 5 2010-01-01 2010-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION...
Arrival first queueing networks with applications in kanban production systems
Boucherie, R.J.; Chao, X.; Miyazawa, M.
2001-01-01
In this paper we introduce a new class of queueing networks called {\\it arrival first networks}. We characterise its transition rates and derive the relationship between arrival rules, linear partial balance equations, and product form stationary distributions. This model is motivated by production
Arrival first queueing networks with applications in kanban production systems
Boucherie, Richardus J.; Chao, X.; Miyazawa, M.
2003-01-01
In this paper, we introduce a new class of queueing networks called arrival first networks. We characterise its transition rates and derive the relationship between arrival rules, linear partial balance equations, and product form stationary distributions. This model is motivated by production
Forecasting Tourist Arrivals and Supply and Demand Gap Analysis ...
African Journals Online (AJOL)
This paper aims to forecast the long term behavior of tourist arrivals and analyze the gap between supply and demand for the hotel/accommodation sector of the city of Addis Ababa. It also intends to provide vital information in regards to the sparse knowledge in the subject of forecasting tourist arrivals in Ethiopia.
14 CFR 93.29 - International Arrival Authorizations.
2010-01-01
... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false International Arrival Authorizations. 93.29... at Chicago O'Hare International Airport § 93.29 International Arrival Authorizations. (a) Except as... marketing arrangement unless the flight was predominately marketed, by contract, under the control of...
9 CFR 93.804 - Declaration upon arrival.
2010-01-01
... FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93.804 Declaration upon arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a..., rhinoceros, or tapir was shipped; (h) The number, species, and purpose of importation of the elephant...
Causes and Consequences of Late Arrival in Labour | Aziken ...
African Journals Online (AJOL)
Background: The outcome of labour depends to a large extent on the quality of intrapartum care given. Prompt arrival in hospital is essential for optimal care of parturient women. The causes and consequences of late arrival in labour have not been analysed in our setting. Objective: To determine the causes and ...
Factors Delaying Hospital Arrival Aftr Acute Stroke Onset
Directory of Open Access Journals (Sweden)
Ghiasian M
2017-03-01
Full Text Available Introduction: Optimal time of referral aftr stroke and the use of new therapies, such as r-tPA and blood pressure control, could accelerate symptoms recovery aftr stroke. Th aim of this study was to investigate factors contributing to the delay in referral to hospitals aftr the occurrence of acute stroke. Methods: Ths analytic-descriptive study included 425 patients, who had referred to the Hamadan Farshchian hospital during years 2015 and 2016. Demographic data, time of referring to medical center, the time of occurrence of stroke, risk factors, clinical symptoms of stroke, way of referring, distance from medical center and type of stroke by using a questionnaire and checklist were recorded. Th SPSS (version 16 softare was used for all calculations. Results: Th mean age of patients in this study was 70.12 years old. Overall, 260 patients (61.2% were male and 85.6% had ischemic stroke. Mean time of referral to fist treatment center and Farshchian hospital was 2.06 and 4.77 hours, respectively. A total of 36.2% patients arrived to Farshchian hospital, within less than 2 hours. Factors that prolonged time to presentation were male gender, ischemic stroke, low education, being at a location far from the medical center, referral from other medical centers, being single, having no witness during stroke, and having a stroke at home, and during night. Th most common symptoms in patients who were referred within less than two hours were confusion and loss of consciousness with frequency of 29.2%. Th most common risk factor in 61.4% of patients, who were referred within less than 2 hours, was high blood pressure. Conclusion: Ths study showed mean time of referral for treatment aftr stroke was high. Inflential elements that could possibly delay hospital arrival include, being at a location far from the medical center, no adequate knowledge about stroke symptom, having stroke at night, not referring directly to the medical center, being single, and no
Niranjan, S. P.; Chandrasekaran, V. M.; Indhira, K.
2017-11-01
The objective of this paper is to analyse state dependent arrival in bulk retrial queueing system with immediate Bernoulli feedback, multiple vacations, threshold and constant retrial policy. Primary customers are arriving into the system in bulk with different arrival rates λ a and λ b . If arriving customers find the server is busy then the entire batch will join to orbit. Customer from orbit request service one by one with constant retrial rate γ. On the other hand if an arrival of customers finds the server is idle then customers will be served in batches according to general bulk service rule. After service completion, customers may request service again with probability δ as feedback or leave from the system with probability 1 - δ. In the service completion epoch, if the orbit size is zero then the server leaves for multiple vacations. The server continues the vacation until the orbit size reaches the value ‘N’ (N > b). At the vacation completion, if the orbit size is ‘N’ then the server becomes ready to provide service for customers from the main pool or from the orbit. For the designed queueing model, probability generating function of the queue size at an arbitrary time will be obtained by using supplementary variable technique. Various performance measures will be derived with suitable numerical illustrations.
Cancellation of spurious arrivals in Green's function extraction and the generalized optical theorem
Snieder, R.; Van Wijk, K.; Haney, M.; Calvert, R.
2008-01-01
The extraction of the Green's function by cross correlation of waves recorded at two receivers nowadays finds much application. We show that for an arbitrary small scatterer, the cross terms of scattered waves give an unphysical wave with an arrival time that is independent of the source position. This constitutes an apparent inconsistency because theory predicts that such spurious arrivals do not arise, after integration over a complete source aperture. This puzzling inconsistency can be resolved for an arbitrary scatterer by integrating the contribution of all sources in the stationary phase approximation to show that the stationary phase contributions to the source integral cancel the spurious arrival by virtue of the generalized optical theorem. This work constitutes an alternative derivation of this theorem. When the source aperture is incomplete, the spurious arrival is not canceled and could be misinterpreted to be part of the Green's function. We give an example of how spurious arrivals provide information about the medium complementary to that given by the direct and scattered waves; the spurious waves can thus potentially be used to better constrain the medium. ?? 2008 The American Physical Society.
Optimal control of arrival and service rates in tandem queues
International Nuclear Information System (INIS)
Moustafa, M.S.
1995-08-01
We consider n M/M/1 queues in series. At queue one the arrival and service rates are chosen in pair from a finite set whenever there are arrivals or service completions at any queue. Customers arriving to queue L (L=1,2,...,n-1) must go on to queue L+1 after finishing service at server L. Customers arriving to queue n leave the system after finishing service at the last server. At queues 2 to n arrival and service rates are fixed. The objective is to minimize the expected discounted cost of the system over finite and infinite horizons. We show that the optimal policy is of threshold type. In order to establish the result, we formulate the optimal control problem as a Linear Programming. (author). 9 refs
Yushkanov, A. A.; Zverev, N. V.
2018-03-01
An influence of quantum and spatial dispersion properties of the non-degenerate electron plasma on the interaction of electromagnetic P-waves with one-dimensional photonic crystal consisting of conductor with low carrier electron density and transparent dielectric matter, is studied numerically. It is shown that at the frequencies of order of the plasma frequency and at small widths of the conducting and dielectric layers of the photonic crystal, optical coefficients in the quantum non-degenerate plasma approach differ from the coefficients in the classical electron gas approach. And also, at these frequencies one observes a temperature dependence of the optical coefficients.
Advanced spring arrival of avian migrants on Tipperne, western Denmark, during 1929-2008
DEFF Research Database (Denmark)
Petersen, Troels Leuenhagen; Meltofte, Hans; Tøttrup, Anders Peter Them
2012-01-01
to specific species groups. In the present study, we analysed temporal patterns in spring arrival of 43 taxonomically diverse Fennoscandian bird species based on a long-term data series covering 80 years (1929-2008) from the Tipperne reserve in westernmost Denmark. Furthermore, we assessed how spring arrival......During the last decade, phenological studies have increased our knowledge on climate-induced changes in timing of avian migration. Much work has been done using long-term, standardised data. However, the vast majority of previous studies have focused on data covering 3-4 decades and limited...
Zhang, Yong; Meerschaert, Mark M.; Baeumer, Boris; LaBolle, Eric M.
2015-08-01
This study develops an explicit two-step Lagrangian scheme based on the renewal-reward process to capture transient anomalous diffusion with mixed retention and early arrivals in multidimensional media. The resulting 3-D anomalous transport simulator provides a flexible platform for modeling transport. The first step explicitly models retention due to mass exchange between one mobile zone and any number of parallel immobile zones. The mobile component of the renewal process can be calculated as either an exponential random variable or a preassigned time step, and the subsequent random immobile time follows a Hyper-exponential distribution for finite immobile zones or a tempered stable distribution for infinite immobile zones with an exponentially tempered power-law memory function. The second step describes well-documented early arrivals which can follow streamlines due to mechanical dispersion using the method of subordination to regional flow. Applicability and implementation of the Lagrangian solver are further checked against transport observed in various media. Results show that, although the time-nonlocal model parameters are predictable for transport with retention in alluvial settings, the standard time-nonlocal model cannot capture early arrivals. Retention and early arrivals observed in porous and fractured media can be efficiently modeled by our Lagrangian solver, allowing anomalous transport to be incorporated into 2-D/3-D models with irregular flow fields. Extensions of the particle-tracking approach are also discussed for transport with parameters conditioned on local aquifer properties, as required by transient flow and nonstationary media.
An Approximate Dynamic Programming Approach to Urban Freight Distribution with Batch Arrivals
van Heeswijk, W.J.A.; Mes, Martijn R.K.; Schutten, Johannes M.J.; Corman, Francesco; Voβ, Stefan; Negenborn, Rudy R.
2015-01-01
We study an extension of the delivery dispatching problem (DDP) with time windows, applied on LTL orders arriving at an urban consolidation center. Order properties (e.g., destination, size, dispatch window) may be highly varying, and directly distributing an incoming order batch may yield high
International Nuclear Information System (INIS)
Nelson, R.W.
1978-01-01
The versatility of the new contaminant arrival distributions for determining environmental consequences of subsurface pollution problems is demonstrated through application to a transient flow system. Though some of the four phases of the hydrologic evaluations are more complicated because of the time dependence of the flow and input contaminant concentrations, the arrival distributions still effectively summarize the data required to determine the environmental implications. These arrival distributions yield two graphs or tabular sets of data giving the consequences of the subsurface pollution problems in a simple and direct form. 4 refs
DEFF Research Database (Denmark)
Andersen, Christian Walther; Bulava, John; Hörz, Ben
2018-01-01
We present the first direct determination of meson-baryon resonance parameters from a scattering amplitude calculated using lattice QCD. In particular, we calculate the elastic I=3/2, p-wave nucleon-pion amplitude on a single ensemble of Nf=2+1 Wilson-clover fermions with mπ=280 MeV and mK=460 Me......V. At these quark masses, the Δ(1232) resonance pole is found close to the N-π threshold and a Breit-Wigner fit to the amplitude gives gΔNπBW=19.0(4.7) in agreement with phenomenological determinations.......We present the first direct determination of meson-baryon resonance parameters from a scattering amplitude calculated using lattice QCD. In particular, we calculate the elastic I=3/2, p-wave nucleon-pion amplitude on a single ensemble of Nf=2+1 Wilson-clover fermions with mπ=280 MeV and mK=460 Me...
International Nuclear Information System (INIS)
Matsui, Yoshiko
1999-01-01
In order to investigate the p-wave contribution from the 3+1-subamplitude in the S-wave phase shift for boson-triboson elastic scattering when the Yamaguchi potential for the two-body interaction is assumed, the Faddeev-Osborn equation for a system of four identical bosons in solved numerically by extending the previous calculation to include the p-wave component for the 3+1-subamplitude. The results obtained closely resemble the previous results. The calculated phase shift generally has the standard behavior of the two-body phase shift for a loosely bound state and has further characteristic behavior represented by a valley witha peak as fine structure. The phase shift obtained in the present calculation has a higher peak and a deeper valley than the previous one, while the positions of the peak and the valley in the two sets of results agree precisely. Thus the calculated resonance energies are the same as those obtained in the previous result. (author)
Rhode, A.; Lay, T.
2017-12-01
Determining the up-dip rupture extent of large megathrust ruptures is important for understanding their tsunami excitation, frictional properties of the shallow megathrust, and potential for separate tsunami earthquake occurrence. On land geodetic data have almost no resolution of the up-dip extent of faulting and teleseismic observations have limited resolution that is strongly influenced by typically poorly known shallow seismic velocity structure near the toe of the accretionary prism. The increase in ocean depth as slip on the megathrust approaches the trench has significant influence on the strength and azimuthal distribution of water reverberations in the far-field P wave coda. For broadband P waves from large earthquakes with dominant signal periods of about 10 s, water reverberations generated by shallow fault slip under deep water may persist for over a minute after the direct P phases have passed, giving a clear signal of slip near the trench. As the coda waves can be quickly evaluated following the P signal, recognition of slip extending to the trench and associated enhanced tsunamigenic potential could be achieved within a few minutes after the P arrival, potentially contributing to rapid tsunami hazard assessment. We examine the broadband P wave coda at distances from 80 to 120° for a large number of recent major and great earthquakes with independently determined slip distributions and known tsunami excitation to evaluate the prospect for rapidly constraining up-dip rupture extent of large megathrust earthquakes. Events known to have significant shallow slip, at least locally extending to the trench (e.g., 2016 Illapel, Chile; 2010 Maule, 2010 Mentawai) do have relatively enhanced coda levels at all azimuths, whereas events that do not rupture the shallow megathrust (e.g., 2007 Sumatra, 2014 Iquique, 2003 Hokkaido) do not. Some events with slip models lacking shallow slip show strong coda generation, raising questions about the up-dip resolution of
Urban sprawl and delayed ambulance arrival in the U.S.
Trowbridge, Matthew J; Gurka, Matthew J; O'Connor, Robert E
2009-11-01
Minimizing emergency medical service (EMS) response time is a central objective of prehospital care, yet the potential influence of built environment features such as urban sprawl on EMS system performance is often not considered. This study measures the association between urban sprawl and EMS response time to test the hypothesis that features of sprawling development increase the probability of delayed ambulance arrival. In 2008, EMS response times for 43,424 motor-vehicle crashes were obtained from the Fatal Analysis Reporting System, a national census of crashes involving > or =1 fatality. Sprawl at each crash location was measured using a continuous county-level index previously developed by Ewing et al. The association between sprawl and the probability of a delayed ambulance arrival (> or =8 minutes) was then measured using generalized linear mixed modeling to account for correlation among crashes from the same county. Urban sprawl is significantly associated with increased EMS response time and a higher probability of delayed ambulance arrival (p=0.03). This probability increases quadratically as the severity of sprawl increases while controlling for nighttime crash occurrence, road conditions, and presence of construction. For example, in sprawling counties (e.g., Fayette County GA), the probability of a delayed ambulance arrival for daytime crashes in dry conditions without construction was 69% (95% CI=66%, 72%) compared with 31% (95% CI=28%, 35%) in counties with prominent smart-growth characteristics (e.g., Delaware County PA). Urban sprawl is significantly associated with increased EMS response time and a higher probability of delayed ambulance arrival following motor-vehicle crashes in the U.S. The results of this study suggest that promotion of community design and development that follows smart-growth principles and regulates urban sprawl may improve EMS performance and reliability.
Energy Technology Data Exchange (ETDEWEB)
Julia, J; Nyblade, A; Hansen, S; Rodgers, A; Matzel, E
2009-07-06
In this project, we are developing models of lithospheric structure for a wide variety of tectonic regions throughout Eurasia and the Middle East by regionalizing 1D velocity models obtained by jointly inverting P-wave and S-wave receiver functions with Rayleigh wave group and phase velocities. We expect the regionalized velocity models will improve our ability to predict travel-times for local and regional phases, such as Pg, Pn, Sn and Lg, as well as travel-times for body-waves at upper mantle triplication distances in both seismic and aseismic regions of Eurasia and the Middle East. We anticipate the models will help inform and strengthen ongoing and future efforts within the NNSA labs to develop 3D velocity models for Eurasia and the Middle East, and will assist in obtaining model-based predictions where no empirical data are available and for improving locations from sparse networks using kriging. The codes needed to conduct the joint inversion of P-wave receiver functions (PRFs), S-wave receiver functions (SRFs), and dispersion velocities have already been assembled as part of ongoing research on lithospheric structure in Africa. The methodology has been tested with synthetic 'data' and case studies have been investigated with data collected at an open broadband stations in South Africa. PRFs constrain the size and S-P travel-time of seismic discontinuities in the crust and uppermost mantle, SRFs constrain the size and P-S travel-time of the lithosphere-asthenosphere boundary, and dispersion velocities constrain average S-wave velocity within frequency-dependent depth-ranges. Preliminary results show that the combination yields integrated 1D velocity models local to the recording station, where the discontinuities constrained by the receiver functions are superimposed to a background velocity model constrained by the dispersion velocities. In our first year of this project we will (i) generate 1D velocity models for open broadband seismic stations
Concept of Operations for Interval Management Arrivals and Approach
Hicok, Daniel S.; Barmore, Bryan E.
2016-01-01
This paper presents the concept of operations for interval management operations to be deployed in the US National Airspace System (NAS) by the Federal Aviation Administration (FAA) after 2020. The use of interval management operations is described that begin in en route airspace and continue to a termination point inside the arrival terminal area, in a terminal environment that includes other arrival management tools such as arrival metering, Ground-based Interval Management - Spacing (GIM-S), and Terminal Sequencing and Spacing (TSAS). The roles of Air Traffic Controllers and Flight Crews and the ground automation tools that are used by Air Traffic Controllers to enable the primary operation and variations are described.
Narrowband direction of arrival estimation for antenna arrays
Foutz, Jeffrey
2008-01-01
This book provides an introduction to narrowband array signal processing, classical and subspace-based direction of arrival (DOA) estimation with an extensive discussion on adaptive direction of arrival algorithms. The book begins with a presentation of the basic theory, equations, and data models of narrowband arrays. It then discusses basic beamforming methods and describes how they relate to DOA estimation. Several of the most common classical and subspace-based direction of arrival methods are discussed. The book concludes with an introduction to subspace tracking and shows how subspace tr
Alkhalifah, Tariq Ali
2016-01-01
The leading component of the high-frequency asymptotic description of the wavefield, given by the travel time, is governed by the eikonal equation. In anisotropic media, traveltime measurements from seismic experiments conducted along one surface
First impression at stroke onset plays an important role in early hospital arrival.
Iguchi, Yasuyuki; Wada, Kuniyasu; Shibazaki, Kensaku; Inoue, Takeshi; Ueno, Yuji; Yamashita, Shinji; Kimura, Kazumi
2006-01-01
Treatment for acute ischemic stroke should be administered as soon as possible after symptom onset. The aim of this study was to investigate whether or not the patient's and bystander's first impression at stroke onset was associated with hospital arrival time. To investigate the factors influencing the prehospital delay, we prospectively interviewed consecutive stroke patients and bystanders about their first impression at the stroke onset and assessed the methods of transportation, and clinical characteristics. Early arrival was defined as a hospital arrival of within 2 h from stroke onset. One hundred thirty patients were enrolled: 82% were ischemic stroke and 18% were cerebral hemorrhage. The median interval between symptom onset and the hospital arrival was 7.5 h and 30% of patients presented within 2 h of stroke onset. First impression of stroke (odds ratios [OR] 4.56, 95% confidence interval [CI] 1.54-13.5, p=0.006), presence of consciousness disturbance (OR 4.29, CI 1.39-13.3, p=0.011), arrival through other facilities (OR 0.25, CI 0.08-0.76, p=0.015), a history of diabetes (OR 0.23, CI 0.06-0.80, p=0.028) and nocturnal onset (OR 0.19, CI 0.04-0.88, p=0.042) independently contributed to the early arrival. The first impression of patients and bystanders at stroke onset is important in order to reach hospital earlier in Japan. Public educational systems such as those, which advertise stroke warning signs, are necessary.
Directory of Open Access Journals (Sweden)
K. Lesley eSzostek
2015-04-01
Full Text Available Changes in the timing of migratory events have been observed recently in many migratory species, most likely in response to climatic change. In the common tern Sterna hirundo we examined such changes in spring arrival date and body mass based on a 19 year individual-based longitudinal data from a transponder marked colony from 1994 - 2012. Although no long-term trend was observed in either trait, strong inter-annual and age-specific variation in arrival date and mass was evident. We investigated whether environmental factors such as (i global climate phenomena North Atlantic and Southern Oscillation Indices NAOI and SOI, or (ii local factors, such as food abundance in the wintering and breeding area, represented by fish stock or marine primary productivity, could explain this variation. We found that 2-year-old birds on their first spring migration advanced arrival relative to spring NAOI and delayed arrival relative to sprat Sprattus sprattus abundance. The arrival date of 3-year-olds also advanced in relation to NAOI and delayed in relation to winter SOI. In contrast, adults delayed arrival with NAOI and advanced relative to SOI. Within age groups, earlier annual arrival coincided with higher mass, indicating that a fast and/or early migration did not come at a cost to body condition. Changes in arrival mass relative to environmental covariates were found only in 2-year-olds on their first spring migration: in these birds arrival mass was positively related to herring Clupea harengus and sprat abundance in the breeding area as well as spring NAOI and negatively related to SOI. In conclusion, traits related to migration of common terns were linked with environmental conditions, but showed no long-term trends over the past two decades. Age-related differences were marked, suggesting that common terns might be subject to differing environmental constraints or respond differently to conditions during their annual cycle depending on age.
U.S. Environmental Protection Agency — This database processes approximately 3,000 Notice of Arrival (NOA) reporting forms from importers and exporters of pesticide products. This is an electronic version...
Obtaining contaminant arrival distributions for steady flow in heterogeneous systems
International Nuclear Information System (INIS)
Anon.
1977-01-01
The versatility of the new contaminant arrival distributions for determining environmental consequences of subsurface pollution problems is demonstrated through application to a field example involving land drainage in heterogeneous porous materials. Though the four phases of the hydrologic evaluations are complicated because of the material heterogeneity encountered in the field problem, the arrival distributions still effectively summarize the minimal amount of data required to determine the environmental implications. These arrival distributions yield a single graph or tabular set of data giving the consequences of the subsurface pollution problems. Accordingly, public control authorities would be well advised to request that the results of subsurface pollution investigations be provided in the form of arrival distributions and the resulting simpler summary curve or tabulation. Such an objective is most easily accomplished through compliance with the requirements for assuring a complete subsurface evaluation
Astronauts Armstrong and Scott arrive at Hickam Field, Hawaii
1966-01-01
Astronauts Neil A. Armstrong (center), command pilot, and David R. Scott, pilot, arrive at Hickam Field, Hawaii on their way from Naha, Okinawa, to Cape Kennedy, Florida. Astronaut Walter M. Schirra Jr. is at extreme left.
Onchocerciasis in the Americas: from arrival to (near) elimination
Sauerbrey Mauricio; Hopkins Adrian; Gustavsen Ken
2011-01-01
Abstract Onchocerciasis (river blindness) is a blinding parasitic disease that threatens the health of approximately 120 million people worldwide. While 99% of the population at-risk for infection from onchocerciasis live in Africa, some 500,000 people in the Americas are also threatened by infection. A relatively recent arrival to the western hemisphere, onchocerciasis was brought to the New World through the slave trade and spread through migration. The centuries since its arrival have seen...
19 CFR 123.61 - Baggage arriving in baggage car.
2010-04-01
... 19 Customs Duties 1 2010-04-01 2010-04-01 false Baggage arriving in baggage car. 123.61 Section... car. An inward foreign manifest on Customs Form 7533 shall be used for all baggage arriving in baggage cars. [T.D. 70-121, 35 FR 8215, May 26, 1970, as amended by T.D. 82-145, 47 FR 35478, Aug. 16, 1982] ...
Tang, Tie-Qiao; Wang, Tao; Chen, Liang; Huang, Hai-Jun
2018-01-01
In this paper, we introduce the fuel cost into each commuter's trip cost, define a new trip cost without late arrival and its corresponding equilibrium state, and use a car-following model to explore the impacts of the fuel cost on each commuter's departure time, departure interval, arrival time, arrival interval, traveling time, early arrival time and trip cost at the above equilibrium state. The numerical results show that considering the fuel cost in each commuter's trip cost has positive impacts on his trip cost and fuel cost, and the traffic situation in the system without late arrival, i.e., each commuter should explicitly consider the fuel cost in his trip cost.
Alkhalifah, Tariq Ali
2016-12-17
The leading component of the high-frequency asymptotic description of the wavefield, given by the travel time, is governed by the eikonal equation. In anisotropic media, traveltime measurements from seismic experiments conducted along one surface cannot constrain the long-wavelength attribute of the medium along the orthogonal-to-the-surface direction, as anisotropy introduces an independent parameter controlling wave propagation in the orthogonal direction. Since travel times measured on the Earth\\'s surface in transversely isotropic media with a vertical symmetry axis are mainly insensitive to the absolute value of the anisotropic parameter responsible for relating these observations to depth δ, the travel time was perturbed laterally to investigate the traveltime sensitivity to lateral variations in δ. This formulation can be used to develop inversion strategies for lateral variations in δ in acoustic transversely isotropic media, as the surface-recorded data are sensitive to it even if the model is described by the normal moveout velocity and horizontal velocity, or the anellipticity parameter η. Numerical tests demonstrate the enhanced sensitivity of our data when the model is parameterised with a lateral change in δ.