Science.gov

Sample records for p-wave arrival times

  1. P wave velocity tomography of the Venezuelan region from local arrival times

    NASA Astrophysics Data System (ADS)

    Bosch, Miguel

    1997-03-01

    Arrival times from the local seismological network of Venezuela were used to estimate a three-dimensional P wave velocity model for the region between longitude 60°-74° W and latitude 6°-14° N to a depth of more than 80 km. The inversion was carried out by damped least squares, describing the media by homogeneous velocity blocks. The resolved lateral velocity variations in the first layer (0-30 km depth) showed a correlation with the main stratigraphic features of the area, while second layer (30-50 km depth) showed the influence of Moho depth variations through the region, generating a pattern well correlated to the Bouguer Anomaly Map. Lithospheric seismic velocities below the Moho appear to be influenced by the major crustal fault systems. An important low-velocity zone is present below the triple junction of the fault systems of Oca, Boconó, and Morón in northwestern Venezuela. Farther south, a similar low-velocity zone is present below the junction of the Boconó and the Santa Marta fault systems. Those are the two continental corners of the triangular Maracaibo Block. Below 80 km depth (the fourth layer) the low velocity zones show a connected pattern that follows or is adjacent to the crustal fault zones. The presence of subducted Atlantic lithosphere below the Eastern Venezuelan Basin could explain the high-velocity zone at this location. A similar interpretation emerges from the tectonic wedging model, previously proposed to explain the pronounced minimum of the gravity anomaly.

  2. A non-parametric method for automatic determination of P-wave and S-wave arrival times: application to local micro earthquakes

    NASA Astrophysics Data System (ADS)

    Rawles, Christopher; Thurber, Clifford

    2015-08-01

    We present a simple, fast, and robust method for automatic detection of P- and S-wave arrivals using a nearest neighbours-based approach. The nearest neighbour algorithm is one of the most popular time-series classification methods in the data mining community and has been applied to time-series problems in many different domains. Specifically, our method is based on the non-parametric time-series classification method developed by Nikolov. Instead of building a model by estimating parameters from the data, the method uses the data itself to define the model. Potential phase arrivals are identified based on their similarity to a set of reference data consisting of positive and negative sets, where the positive set contains examples of analyst identified P- or S-wave onsets and the negative set contains examples that do not contain P waves or S waves. Similarity is defined as the square of the Euclidean distance between vectors representing the scaled absolute values of the amplitudes of the observed signal and a given reference example in time windows of the same length. For both P waves and S waves, a single pass is done through the bandpassed data, producing a score function defined as the ratio of the sum of similarity to positive examples over the sum of similarity to negative examples for each window. A phase arrival is chosen as the centre position of the window that maximizes the score function. The method is tested on two local earthquake data sets, consisting of 98 known events from the Parkfield region in central California and 32 known events from the Alpine Fault region on the South Island of New Zealand. For P-wave picks, using a reference set containing two picks from the Parkfield data set, 98 per cent of Parkfield and 94 per cent of Alpine Fault picks are determined within 0.1 s of the analyst pick. For S-wave picks, 94 per cent and 91 per cent of picks are determined within 0.2 s of the analyst picks for the Parkfield and Alpine Fault data set, respectively. For the Parkfield data set, our method picks 3520 P-wave picks and 3577 S-wave picks out of 4232 station-event pairs. For the Alpine Fault data set, the method picks 282 P-wave picks and 311 S-wave picks out of a total of 344 station-event pairs. For our testing, we note that the vast majority of station-event pairs have analyst picks, although some analyst picks are excluded based on an accuracy assessment. Finally, our tests suggest that the method is portable, allowing the use of a reference set from one region on data from a different region using relatively few reference picks.

  3. Detection of anomalous features in an earthen dam using inversion of P-wave first-arrival times and surface-wave dispersion curves

    NASA Astrophysics Data System (ADS)

    Kim, K. Y.; Jeon, K. M.; Hong, M. H.; Park, Young-gyu

    2011-02-01

    To locate anomalous features including seepage pathways through the Daeryong earth-fill dam, P and Rayleigh waves were recorded along a 250-m profile on the crest of the dam. Seismic energy was generated using a 5-kg sledgehammer and detected by 24 4.5-Hz vertical-axis geophones installed at 3-m intervals. P-wave and apparent S-wave velocities of the reservoir dam and underlying bedrock were then inverted from first-arrival traveltimes and dispersion curves of Rayleigh waves, respectively. Apparent dynamic Poisson's ratios as high as 0.46 were obtained at the base of the dam near its north-east end, where an outlet conduit occurs, and in the clay core body near the south-west end of the profile where the dam was repeatedly grouted to abate seepage before our survey. These anomalies of higher Poisson's ratios in the upper part of clay core were also associated with effusion of grout on the downstream slope of the dam during post-survey grouting to abate leakage. Combining P-wave traveltime tomography and inversion of Rayleigh wave velocities was very effective in detecting potential pathways for seepage and previous grouted zones in this earthen dam.

  4. Microseismic event location using an inverse method of joint P-S phase arrival difference and P-wave arrival difference in a borehole system

    NASA Astrophysics Data System (ADS)

    Zhou, Wen; Wang, Liangshu; Guan, Luping; Guo, Quanshi; Cui, Shuguo; Yu, Bo

    2015-04-01

    The accuracy of hypocenter location is the essential issue for microseismic monitoring, and is the basis for evaluating the effect of fracture. Although the signal obtained from a borehole monitoring system has a higher signal to noise ratio (SNR) than the surface system, a narrow monitoring aperture makes the location sensitive to noise and tends to be a misguided shape. In order to overcome this disadvantage and obtain a more accurate estimation of the source, we develop a ‘jointing method’, which combines the P-S phase arrival difference and P-wave arrival difference of each receiver pair (PSP) in the objective function. In the synthetic example, we compare the noise responses of three different location methods which are based on P-wave arrival time difference, P-S wave arrival time difference and the PSP method, respectively. This analysis shows that the P-wave arrival difference method is more sensitive to arrival time error than the others and the location results tend to be in a misleading line directed to the receivers. The P-S arrival difference method is more robust than the method using P-wave and its error distribution is perpendicular to the ray-path direction. The PSP method, as expected, is the most stable and accurate. When the P-S method and PSP method are applied to field data of a coal bed methane hydro-fracture process monitoring, the results indicate that the PSP method is preferable. The successful location with the PSP method proves that it is suitable for field data.

  5. Time corrections to teleseismic P delays derived from SKS splitting parameters and implications for western U.S. P-wave tomography

    NASA Astrophysics Data System (ADS)

    O'Driscoll, Leland J.; Humphreys, Eugene D.; Schmandt, Brandon

    2011-10-01

    Upper mantle anisotropy will affect teleseismic P-wave arrival times and create artifacts in isotropic travel-time tomography. Compiled SKS splitting results indicate variations in the strength and orientation of azimuthal anisotropy beneath the western U.S. We use SKS splitting parameters and a hexagonally anisotropic elastic tensor (fast symmetry axis) to estimate azimuthal anisotropy contributions to P-wave delay times and evaluate the effects on isotropic P-wave tomography. Estimated anisotropy correction times have a root-mean-square (RMS) value of 0.16 s, which is 37% of P-wave delay time RMS. The magnitude of azimuthal anisotropy, rather than its azimuth, has the strongest effect on P delay times; however, if the anisotropy symmetry axis has a plunge, P-wave travel times may be strongly affected by both magnitude and azimuth. Applying azimuthal anisotropy corrections significantly increases tomographic P-wave velocity beneath the High Lava Plains and central California coast, and decreases velocity beneath the Great Basin.

  6. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume II P-Wave Measurements in Borehole C4996 Seismic Records, Wave-Arrival Identifications and Interpreted P-Wave Velocity Profile.

    SciTech Connect

    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.

  7. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume I P-Wave Measurements in Borehole C4993 Seismic Records, Wave-Arrival Identifications and Interpreted P-Wave Velocity Profile.

    SciTech Connect

    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.

  8. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume III P-Wave Measurements in Borehole C4997 Seismic Records, Wave-Arrival Identifications and Interpreted P-Wave Velocity Profile.

    SciTech Connect

    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.

  9. Walk -Run Activity --An S and P Wave Travel Time ("S minus P" Earthquake Location Method)

    E-print Network

    Smith-Konter, Bridget

    Walk - Run Activity --An S and P Wave Travel Time Simulation ("S minus P" Earthquake Location between distance and time of travel of seismic waves (a travel time-curve). To use the constructed time-travel pencils) Procedure: Part One: Constructing the Travel-Time Graph To model how earthquake waves travel

  10. Quantum arrival time for open systems

    SciTech Connect

    Yearsley, J. M.

    2010-07-15

    We extend previous work on the arrival time problem in quantum mechanics, in the framework of decoherent histories, to the case of a particle coupled to an environment. The usual arrival time probabilities are related to the probability current, so we explore the properties of the current for general open systems that can be written in terms of a master equation of the Lindblad form. We specialize to the case of quantum Brownian motion, and show that after a time of order the localization time of the current becomes positive. We show that the arrival time probabilities can then be written in terms of a positive operator-valued measure (POVM), which we compute. We perform a decoherent histories analysis including the effects of the environment and show that time-of-arrival probabilities are decoherent for a generic state after a time much greater than the localization time, but that there is a fundamental limitation on the accuracy {delta}t, with which they can be specified which obeys E{delta}t>>({h_bar}/2{pi}). We confirm that the arrival time probabilities computed in this way agree with those computed via the current, provided there is decoherence. We thus find that the decoherent histories formulation of quantum mechanics provides a consistent explanation for the emergence of the probability current as the classical arrival time distribution, and a systematic rule for deciding when probabilities may be assigned.

  11. Travel time delays and slowness vector deviations interpretation of multiply reflected P waves

    NASA Astrophysics Data System (ADS)

    Foundotos, M.; Nolet, G.

    2013-12-01

    From a previous study we have shown that it was possible to observe multiply reflected P waves such as PPP, PPPP, PPPPP, PPPPPP. Despite the ray theoretical prediction that at a certain distance most of their compressional energy is converted to shear waves. A 1D P-velocity model for the pacific region was also proposed. The purpose of this new study is to make measurements of travel time delay and slowness vector deviation of these waves. We used about 400 events of magnitude Mw > 6.1 recorded from the dense network of US ARRAY, which allows us to make a very large number of travel time delays and slowness vector perturbation measurements of multiply reflected P waves. These measurements show that multiply reflected P wave are of great interests when studying the Upper mantle structure.

  12. Resolving P-wave travel-time anomalies using seismic array observations of oceanic storms

    E-print Network

    Gerstoft, Peter

    Resolving P-wave travel-time anomalies using seismic array observations of oceanic storms Jian body-wave tomography storm Array analysis of seismic noise has the potential to be very useful proven successful in surface-wave tomography. Beamforming of seismic noise recorded in southern

  13. HELCATS Prediction of Planetary CME arrival times

    NASA Astrophysics Data System (ADS)

    Boakes, Peter; Moestl, Christian; Davies, Jackie; Harrison, Richard; Byrne, Jason; Barnes, David; Isavnin, Alexey; Kilpua, Emilia; Rollett, Tanja

    2015-04-01

    We present the first results of CME arrival time prediction at different planetary locations and their comparison to the in situ data within the HELCATS project. The EU FP7 HELCATS (Heliospheric Cataloguing, Analysis & Techniques Service) is a European effort to consolidate the exploitation of the maturing field of heliospheric imaging. HELCATS aims to catalogue solar wind transients, observed by the NASA STEREO Heliospheric Imager (HI) instruments, and validate different methods for the determination of their kinematic properties. This validation includes comparison with arrivals at Earth, and elsewhere in the heliosphere, as well as onsets at the Sun (http://www.helcats-fp7.eu/). A preliminary catalogue of manually identified CMEs, with over 1000 separate events, has been created from observations made by the STEREO/HI instruments covering the years 2007-2013. Initial speeds and directions of each CME have been derived through fitting the time elongation profile to the state of the art Self-Similar Expansion Fitting (SSEF) geometric technique (Davies et al., 2012). The technique assumes that, in the plane corresponding to the position angle of interest, CMEs can be modelled as circles subtending a fixed angular width to Sun-center and propagating anti-sunward in a fixed direction at a constant speed (we use an angular width of 30 degrees in our initial results). The model has advantages over previous geometric models (e.g. harmonic mean or fixed phi) as it allows one to predict whether a CME will 'hit' a specific heliospheric location, as well as to what degree (e.g. direct assault or glancing blow). We use correction formulae (Möstl and Davies, 2013) to convert CME speeds, direction and launch time to speed and arrival time at any in situ location. From the preliminary CME dataset, we derive arrival times for over 400 Earth-directed CMEs, and for over 100 Mercury-, Venus-, Mars- and Saturn-directed CMEs predicted to impact each planet. We present statistics of predicted CME arrival properties. In addition, we independently identify CME arrival at in situ locations using magnetic field data from the Venus Express, Messenger, and Ulysses spacecraft and show first comparisons to predicted arrival times. The results hold important implications for space weather prediction at Earth and other locations, allowing model and predicted CME parameters to be compared to their in situ counterparts.

  14. Target tracking and Estimated Time of Arrival (ETA) Prediction for Arrival Aircraft

    E-print Network

    Zakhor, Avideh

    Target tracking and Estimated Time of Arrival (ETA) Prediction for Arrival Aircraft Kaushik Roy Benjamin Levy Claire J. Tomlin§ The problem of developing a unified algorithm for arrival aircraft target. One bottleneck in the flow of aircraft is traffic on the surface of and in the air surrounding

  15. Acceleration of stable TTI P-wave reverse-time migration with GPUs

    NASA Astrophysics Data System (ADS)

    Kim, Youngseo; Cho, Yongchae; Jang, Ugeun; Shin, Changsoo

    2013-03-01

    When a pseudo-acoustic TTI (tilted transversely isotropic) coupled wave equation is used to implement reverse-time migration (RTM), shear wave energy is significantly included in the migration image. Because anisotropy has intrinsic elastic characteristics, coupling P-wave and S-wave modes in the pseudo-acoustic wave equation is inevitable. In RTM with only primary energy or the P-wave mode in seismic data, the S-wave energy is regarded as noise for the migration image. To solve this problem, we derive a pure P-wave equation for TTI media that excludes the S-wave energy. Additionally, we apply the rapid expansion method (REM) based on a Chebyshev expansion and a pseudo-spectral method (PSM) to calculate spatial derivatives in the wave equation. When REM is incorporated with the PSM for the spatial derivatives, wavefields with high numerical accuracy can be obtained without grid dispersion when performing numerical wave modeling. Another problem in the implementation of TTI RTM is that wavefields in an area with high gradients of dip or azimuth angles can be blown up in the progression of the forward and backward algorithms of the RTM. We stabilize the wavefields by applying a spatial-frequency domain high-cut filter when calculating the spatial derivatives using the PSM. In addition, to increase performance speed, the graphic processing unit (GPU) architecture is used instead of traditional CPU architecture. To confirm the degree of acceleration compared to the CPU version on our RTM, we then analyze the performance measurements according to the number of GPUs employed.

  16. Alternative stable qP wave equations in TTI media with their applications for reverse time migration

    NASA Astrophysics Data System (ADS)

    Zhou, Yang; Wang, Huazhong; Liu, Wenqing

    2015-10-01

    Numerical instabilities may arise if the spatial variation of symmetry axis is handled improperly when implementing P-wave modeling and reverse time migration in heterogeneous tilted transversely isotropic (TTI) media, especially in the cases where fast changes exist in TTI symmetry axis’ directions. Based on the pseudo-acoustic approximation to anisotropic elastic wave equations in Cartesian coordinates, alternative second order qP (quasi-P) wave equations in TTI media are derived in this paper. Compared with conventional stable qP wave equations, the proposed equations written in stress components contain only spatial derivatives of wavefield variables (stress components) and are free from spatial derivatives involving media parameters. These lead to an easy and efficient implementation for stable P-wave modeling and imaging. Numerical experiments demonstrate the stability and computational efficiency of the presented equations in complex TTI media.

  17. Cascadia tremor located near plate interface constrained by S minus P wave times.

    PubMed

    La Rocca, Mario; Creager, Kenneth C; Galluzzo, Danilo; Malone, Steve; Vidale, John E; Sweet, Justin R; Wech, Aaron G

    2009-01-30

    Nonvolcanic tremor is difficult to locate because it does not produce impulsive phases identifiable across a seismic network. An alternative approach to identifying specific phases is to measure the lag between the S and P waves. We cross-correlate vertical and horizontal seismograms to reveal signals common to both, but with the horizontal delayed with respect to the vertical. This lagged correlation represents the time interval between vertical compressional waves and horizontal shear waves. Measurements of this interval, combined with location techniques, resolve the depth of tremor sources within +/-2 kilometers. For recent Cascadia tremor, the sources locate near or on the subducting slab interface. Strong correlations and steady S-P time differences imply that tremor consists of radiation from repeating sources. PMID:19179527

  18. Fast determination of earthquake magnitude and fault extent from real-time P-wave recordings

    NASA Astrophysics Data System (ADS)

    Colombelli, Simona; Zollo, Aldo

    2015-08-01

    This work is aimed at the automatic and fast characterization of the extended earthquake source, through the progressive measurement of the P-wave displacement amplitude along the recorded seismograms. We propose a straightforward methodology to quickly characterize the earthquake magnitude and the expected length of the rupture, and to provide an approximate estimate of the average stress drop to be used for Earthquake Early Warning and rapid response purposes. We test the methodology over a wide distance and magnitude range using a massive Japan earthquake, accelerogram data set. Our estimates of moment magnitude, source duration/length and stress drop are consistent with the ones obtained by using other techniques and analysing the whole seismic waveform. In particular, the retrieved source parameters follow a self-similar, constant stress-drop scaling (median value of stress drop = 0.71 MPa). For the M 9.0, 2011 Tohoku-Oki event, both magnitude and length are underestimated, due to limited, available P-wave time window (PTWs) and to the low-frequency cut-off of analysed data. We show that, in a simulated real-time mode, about 1-2 seconds would be required for the source parameter determination of M 4-5 events, 3-10 seconds for M 6-7 and 30-40 s for M 8-8.5. The proposed method can also provide a rapid evaluation of the average slip on the fault plane, which can be used as an additional discriminant for tsunami potential, associated to large magnitude earthquakes occurring offshore.

  19. A 1D P wave velocity model under the pacific region using multiply reflected P waves

    NASA Astrophysics Data System (ADS)

    Foundotos, M.; Nolet, G.

    2012-12-01

    In order to constrain the shallow structure of the Earth in global tomography, Love and Rayleigh waves are often used. However these waves are mostly sensitive to the S wave velocity structure. P-wave energy is either evanescent, or leaking away at every surface reflection that generates an S wave which travels much deeper into the mantle. For that reason, to study the shallow P velocity structure of the Earth, we need to study P-waves at regional distances if a good seismic station coverage is available. Otherwise we can use multiply reflected P waves at teleseismic distance when regional data are not available (as in the oceans for instance). We used 203 events of magnitude Mw > 6.0 recorded from the dense network of US ARRAY, which allows us to make a very large number of group arrival and slowness measurements of multiply reflected P waves . Our study shows that two times reflected PPP and three times reflected PPPP waves are very well observed despite the ray- theoretical prediction that at certain distances almost all of their compressional energy is converted to shear waves. We also observed Four times reflected 5P and five times reflected 6P which show a strong interference for epicentral distances larger than 80 degree. These observations of multiply reflected P waves allow us to inferred a 1D P wave model for the shallow structure under the pacific region.

  20. Three-dimensional seismic tomography from P wave and S wave microearthquake travel times and rock physics characterization of the Campi Flegrei Caldera

    NASA Astrophysics Data System (ADS)

    Vanorio, T.; Virieux, J.; Capuano, P.; Russo, G.

    2005-03-01

    The Campi Flegrei (CF) Caldera experiences dramatic ground deformations unsurpassed anywhere in the world. The source responsible for this phenomenon is still debated. With the aim of exploring the structure of the caldera as well as the role of hydrothermal fluids on velocity changes, a multidisciplinary approach dealing with three-dimensional delay time tomography and rock physics characterization has been followed. Selected seismic data were modeled by using a tomographic method based on an accurate finite difference travel time computation which simultaneously inverts P wave and S wave first-arrival times for both velocity model parameters and hypocenter locations. The retrieved P wave and S wave velocity images as well as the deduced Vp/Vs images were interpreted by using experimental measurements of rock physical properties on CF samples to take into account steam/water phase transition mechanisms affecting P wave and S wave velocities. Also, modeling of petrophysical properties for site-relevant rocks constrains the role of overpressured fluids on velocity. A flat and low Vp/Vs anomaly lies at 4 km depth under the city of Pozzuoli. Earthquakes are located at the top of this anomaly. This anomaly implies the presence of fractured overpressured gas-bearing formations and excludes the presence of melted rocks. At shallow depth, a high Vp/Vs anomaly located at 1 km suggests the presence of rocks containing fluids in the liquid phase. Finally, maps of the Vp*Vs product show a high Vp*Vs horseshoe-shaped anomaly located at 2 km depth. It is consistent with gravity data and well data and might constitute the on-land remainder of the caldera rim, detected below sea level by tomography using active source seismic data.

  1. Final Arrival Location: Final Arrival Date: Final Arrival Time: FOREIGN TRAVEL

    E-print Network

    Bigelow, Stephen

    obtain a Travel Advance for this trip? No Yes Was there any personal time during this trip? No Yes From Registration: Telephone/Fax: Other (explain): Foreign Exchange Fees: Exchange Rate Used: Comments: Account

  2. An Exploratory Study of Runway Arrival Procedures: Time Based Arrival and Self-Spacing

    NASA Technical Reports Server (NTRS)

    Houston, Vincent E.; Barmore, Bryan

    2009-01-01

    The ability of a flight crew to deliver their aircraft to its arrival runway on time is important to the overall efficiency of the National Airspace System (NAS). Over the past several years, the NAS has been stressed almost to its limits resulting in problems such as airport congestion, flight delay, and flight cancellation to reach levels that have never been seen before in the NAS. It is predicted that this situation will worsen by the year 2025, due to an anticipated increase in air traffic operations to one-and-a-half to three times its current level. Improved arrival efficiency, in terms of both capacity and environmental impact, is an important part of improving NAS operations. One way to improve the arrival performance of an aircraft is to enable the flight crew to precisely deliver their aircraft to a specified point at either a specified time or specified interval relative to another aircraft. This gives the flight crew more control to make the necessary adjustments to their aircraft s performance with less tactical control from the controller; it may also decrease the controller s workload. Two approaches to precise time navigation have been proposed: Time-Based Arrivals (e.g., required times of arrival) and Self-Spacing. Time-Based Arrivals make use of an aircraft s Flight Management System (FMS) to deliver the aircraft to the runway threshold at a given time. Self-Spacing enables the flight crew to achieve an ATC assigned spacing goals at the runway threshold relative to another aircraft. The Joint Planning and Development Office (JPDO), a multi-agency initiative established to plan and coordinate the development of the Next Generation Air Transportation System (NextGen), has asked for data for both of these concepts to facilitate future research and development. This paper provides a first look at the delivery performance of these two concepts under various initial and environmental conditions in an air traffic simulation environment.

  3. Final Arrival Location: Final Arrival Date: Final Arrival Time: FOREIGN TRAVEL

    E-print Network

    Bigelow, Stephen

    obtain a Travel Advance for this trip? No Yes Was there any personal time during this trip? No Yes From Registration: Telephone/Fax: Other (explain): Foreign Exchange Fees: Exchange Rate Used: Comments: Account DATE Print name and title: RESET UCSB TripID: #12;

  4. Shear wave arrival time estimates correlate with local speckle pattern.

    PubMed

    Mcaleavey, Stephen A; Osapoetra, Laurentius O; Langdon, Jonathan

    2015-12-01

    We present simulation and phantom studies demonstrating a strong correlation between errors in shear wave arrival time estimates and the lateral position of the local speckle pattern in targets with fully developed speckle. We hypothesize that the observed arrival time variations are largely due to the underlying speckle pattern, and call the effect speckle bias. Arrival time estimation is a key step in quantitative shear wave elastography, performed by tracking tissue motion via cross-correlation of RF ultrasound echoes or similar methods. Variations in scatterer strength and interference of echoes from scatterers within the tracking beam result in an echo that does not necessarily describe the average motion within the beam, but one favoring areas of constructive interference and strong scattering. A swept-receive image, formed by fixing the transmit beam and sweeping the receive aperture over the region of interest, is used to estimate the local speckle pattern. Metrics for the lateral position of the speckle are found to correlate strongly (r > 0.7) with the estimated shear wave arrival times both in simulations and in phantoms. Lateral weighting of the swept-receive pattern improved the correlation between arrival time estimates and speckle position. The simulations indicate that high RF echo correlation does not equate to an accurate shear wave arrival time estimate-a high correlation coefficient indicates that motion is being tracked with high precision, but the location tracked is uncertain within the tracking beam width. The presence of a strong on-axis speckle is seen to imply high RF correlation and low bias. The converse does not appear to be true-highly correlated RF echoes can still produce biased arrival time estimates. The shear wave arrival time bias is relatively stable with variations in shear wave amplitude and sign (-20 ?m to 20 ?m simulated) compared with the variation with different speckle realizations obtained along a given tracking vector. We show that the arrival time bias is weakly dependent on shear wave amplitude compared with the variation with axial position/ local speckle pattern. Apertures of f/3 to f/8 on transmit and f/2 and f/4 on receive were simulated. Arrival time error and correlation with speckle pattern are most strongly determined by the receive aperture. PMID:26670847

  5. Constraining dark matter late-time energy injection: decays and p-wave annihilations

    SciTech Connect

    Diamanti, Roberta; Mena, Olga; Palomares-Ruiz, Sergio; Vincent, Aaron C.; Lopez-Honorez, Laura E-mail: llopezho@vub.ac.be E-mail: sergio.palomares.ruiz@ific.uv.es

    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–? 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 ?} = 100 MeV. This bound becomes lower by an order of magnitude at m{sub ?} = 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.

  6. Estimated time of arrival and debiasing the time saving bias.

    PubMed

    Eriksson, Gabriella; Patten, Christopher J D; Svenson, Ola; Eriksson, Lars

    2015-12-01

    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. PMID:26230872

  7. Time-of-arrival probabilities for general particle detectors

    E-print Network

    Charis Anastopoulos; Ntina Savvidou

    2012-07-16

    We develop a general framework for the construction of probabilities for the time of arrival in quantum systems. The time of arrival is identified with the time instant when a transition in the detector's degrees of freedom takes place. Thus, its definition is embedded within the larger issue of defining probabilities with respect to time for general quantum transitions. The key point in our analysis is that we manage to reduce the problem of defining a quantum time observable to a mathematical model where time is associated to a transition from a subspace of the Hilbert space of the total system to its complementary subspace. This property makes it possible to derive a general expression for the probability for the time of transition, valid for any quantum system, with the only requirement that the time of transition is correlated with a definite macroscopic record. The framework developed here allows for the consideration of any experimental configuration for the measurement of the time of arrival and it also applies to relativistic systems with interactions described by quantum field theory. We use the method in order to describe time-of-arrival measurements in high-energy particle reactions and for a rigorous derivation of the time-integrated probabilities in particle oscillations.

  8. A geometrical result regarding time-of-arrival lightning location

    NASA Technical Reports Server (NTRS)

    Solakiewicz, Richard

    1996-01-01

    One reason for investigating Lightning Detection And Ranging (LDAR) is to validate data from the Optical Transient Detector (OTD). A Time-Of-Arrival (TOA) procedure may be used with radio wave portions of lighting signatures. An antenna is in place at KSC.

  9. Arrival Time Distribution by the New Observation System at Taro

    NASA Astrophysics Data System (ADS)

    Sakuyama, H.; Obara, Hitoshi; Kuramochi, Hiroshi; Ono, Shunichi; Origasa, Satoru; Mochida, Akinori; Sakuyama, Hiroshi; Suzuki, Noboru

    2003-07-01

    The arrival time distribution of EAS has been observed by using Ultra Fast Cherenkov detector (UFC) and oscilloscope at Taro observatory since 1995 (sea level 200m). The EAS array is arranged 169 sets of 0.25m2 scintillation detectors in the shape of a lattice at intervals of 1.5m and about 40 scintillation detectors which consists of 1m2 and 0.25m2 is arranged in the peripheral part. Then, it consists of 8 fast timing detectors. The UFC detector is installed in the palce of about 20m from the trigger center. The observation system of a UFC detector was changed from the autumn of 2000. The outline of a new observation system and EAS arrival time distribution are reported.

  10. The arrival time distribution of EAS at Taro

    NASA Astrophysics Data System (ADS)

    Maeda, T.; Kuramochi, H.; Ono, S.; Sakuyama, H.; Suzuki, N.

    The arrival time distribution of EAS has been observed since 1995 at Taro cosmicray laboratory (200m above sea level). The EAS arrays consist of 1m2 and 0.25m2 scintillation detectors, 0.25m2 fast timing counters and ultra fast Cherenkov detectors (UFC). 169 0.25m2 scintillation detectors are arranged in alattice configuration with a unit distance of 1.5m. UFC is placed at 20m from the center of lattice array. The arrival time distribution has been analyzed with distance from EAS core (r=10-60m). One of the results shows that the radius of corvature increases as shower size (Ne), near to the EAS core.

  11. Quantum arrival and dwell times via idealized clocks

    SciTech Connect

    Yearsley, J. M.; Downs, D. A.; Halliwell, J. J.; Hashagen, A. K.

    2011-08-15

    A number of approaches to the problem of defining arrival- and dwell-time probabilities in quantum theory makes use of idealized models of clocks. An interesting question is the extent to which the probabilities obtained in this way are related to standard semiclassical results. In this paper, we explore this question using a reasonably general clock model, solved using path-integral methods. We find that, in the weak-coupling regime, where the energy of the clock is much less than the energy of the particle it is measuring, the probability for the clock pointer can be expressed in terms of the probability current in the case of arrival times, and the dwell-time operator in the case of dwell times, the expected semiclassical results. In the regime of strong system-clock coupling, we find that the arrival-time probability is proportional to the kinetic-energy density, consistent with an earlier model involving a complex potential. We argue that, properly normalized, this may be the generically expected result in this regime. We show that these conclusions are largely independent of the form of the clock Hamiltonian.

  12. Empirical estimation of the arrival time of ICME Shocks

    NASA Astrophysics Data System (ADS)

    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.

  13. Optimal first-arrival times in Lévy flights with resetting

    NASA Astrophysics Data System (ADS)

    Ku?mierz, ?ukasz; Gudowska-Nowak, Ewa

    2015-11-01

    We consider the diffusive motion of a particle performing a random walk with Lévy distributed jump lengths and subject to a resetting mechanism, bringing the walker to an initial position at uniformly distributed times. In the limit of an infinite number of steps and for long times, the process converges to superdiffusive motion with replenishment. We derive a formula for the mean first arrival time (MFAT) to a predefined target position reached by a meandering particle and we analyze the efficiency of the proposed searching strategy by investigating criteria for an optimal (a shortest possible) MFAT.

  14. Optimal first arrival times in Lévy flights with resetting

    E-print Network

    Lukasz Kusmierz; Ewa Gudowska-Nowak

    2015-09-29

    We consider diffusive motion of a particle performing a random walk with L\\'evy distributed jump lengths and subject to resetting mechanism bringing the walker to an initial position at uniformly distributed times. In the limit of infinite number of steps and for long times, the process converges to a super-diffusive motion with replenishment. We derive formula for a mean first arrival time (MFAT) to a predefined target position reached by a meandering particle and analyze efficiency of the proposed searching strategy by investigating criteria for an optimal (a shortest possible) MFAT.

  15. Time of arrival through interacting environments: Tunneling processes

    NASA Astrophysics Data System (ADS)

    Aoki, Ken-Ichi; Horikoshi, Atsushi; Nakamura, Etsuko

    2000-08-01

    We discuss the propagation of wave packets through interacting environments. Such environments generally modify the dispersion relation or shape of the wave function. To study such effects in detail, we define the distribution function PX(T), which describes the arrival time T of a packet at a detector located at point X. We calculate PX(T) for wave packets traveling through a tunneling barrier and find that our results actually explain recent experiments. We compare our results with Nelson's stochastic interpretation of quantum mechanics and resolve a paradox previously apparent in Nelson's viewpoint about the tunneling time.

  16. Early magnitude estimation for the MW7.9 Wenchuan earthquake using progressively expanded P-wave time window

    PubMed Central

    Peng, Chaoyong; Yang, Jiansi; Zheng, Yu; Xu, Zhiqiang; Jiang, Xudong

    2014-01-01

    More and more earthquake early warning systems (EEWS) are developed or currently being tested in many active seismic regions of the world. A well-known problem with real-time procedures is the parameter saturation, which may lead to magnitude underestimation for large earthquakes. In this paper, the method used to the MW9.0 Tohoku-Oki earthquake is explored with strong-motion records of the MW7.9, 2008 Wenchuan earthquake. We measure two early warning parameters by progressively expanding the P-wave time window (PTW) and distance range, to provide early magnitude estimates and a rapid prediction of the potential damage area. This information would have been available 40?s after the earthquake origin time and could have been refined in the successive 20?s using data from more distant stations. We show the suitability of the existing regression relationships between early warning parameters and magnitude, provided that an appropriate PTW is used for parameter estimation. The reason for the magnitude underestimation is in part a combined effect of high-pass filtering and frequency dependence of the main radiating source during the rupture process. Finally we suggest only using Pd alone for magnitude estimation because of its slight magnitude saturation compared to the ?c magnitude. PMID:25346344

  17. The Effects of Predator Arrival Timing on Adaptive Radiation (Invited)

    NASA Astrophysics Data System (ADS)

    Borden, J.; Knope, M. L.; Fukami, T.

    2009-12-01

    Much of Earth’s biodiversity is thought to have arisen by adaptive radiation, the rapid diversification of a single ancestral species to fill a wide-variety of ecological niches. Both theory and empirical evidence have long supported competition for limited resources as a primary driver of adaptive radiation. While predation has also been postulated to be an important selective force during radiation, empirical evidence is surprisingly scant and its role remains controversial. However, two recent empirical studies suggest that predation can promote divergence during adaptive radiation. Using an experimental laboratory microcosm system, we examined how predator arrival timing affects the rate and extent of diversification during adaptive radiation. We varied the introduction timing of a protozoan predator (Tetrahymena thermophila) into populations of the bacteria Pseudomonas flourescens, which is known for its ability to undergo rapid adaptive radiation in aqueous microcosms. While our results show that predator arrival timing may have a significant impact on the rate, but not extent, of diversification, these results are tenuous and should be interpreted with caution, as the protozoan predators died early in the majority of our treatments, hampering our ability for comparison across treatments. Additionally, the abundance of newly derived bacterial genotypes was markedly lower in all treatments than observed in previous experiments utilizing this microbial experimental evolution system. To address these shortcomings, we will be repeating the experiment in the near future to further explore the impact of predator arrival timing on adaptive radiation. Smooth Morph and small-Wrinkly Spreader Pseudomonas flourescens diversification in the 96 hour treatment. Day 10, diluted to 1e-5.

  18. Global-scale P wave tomography optimized for prediction of teleseismic and regional travel times for Middle East events: 1. Data set development

    NASA Astrophysics Data System (ADS)

    Myers, S. C.; Johannesson, G.; Simmons, N. A.

    2011-04-01

    We extend the Bayesloc seismic multiple-event location algorithm for application to global arrival time data sets. Bayesloc is a formulation of the joint probability distribution spanning multiple-event location parameters, including hypocenters, travel time corrections, pick precision, and phase labels. Stochastic priors may be used to constrain any of the Bayesloc parameters. Markov Chain Monte Carlo sampling is used to draw samples from the joint probability distribution, and the posteriori samples are summarized to infer conventional location parameters such as the hypocenter. The first application of the broad area Bayesloc algorithm is to a data set consisting of all well-recorded events in the Middle East and the most well-recorded events with 5° spatial sampling globally. This sampling strategy is designed to provide the ray coverage needed to determine lithospheric-scale P wave velocity structure in the Middle East using the complementary ray geometry provided by regional (subhorizontal) and teleseismic (subvertical) raypaths and to determine a consistent, albeit lower-resolution, image of global mantle structure. The data set consists of 5401 events and 878,535 P, Pn, pP, sP, and PcP arrivals recorded at 4606 stations. Relocated epicenters are an average of 16 km from bulletin locations. The data set included events that are known to an accuracy of 1 km (a.k.a. GT1) based on nonseismic information. The average distance between GT1 epicenters and our relocated epicenters is 5.6 km. For arrivals labeled P, Pn, and PcP, ˜92%, ˜90%, and 96% are properly labeled with probability >0.9, respectively. Incorrect phase labels are found to be erroneous at rates of 0.6%, 0.2%, 1.6%, and 2.5% for P, Pn, PcP, and depth phases (pP and sP), respectively. Labels found to be incorrect, but not erroneous, were reassigned to another phase label. P and Pn residual standard deviation with respect to ak135 travel times are dramatically reduced from 3.45 s to 1.01 s. The differences between travel time residuals for nearly reciprocal raypaths are significantly reduced from the input event locations, suggesting that Bayesloc relocation improves data set consistency. The reciprocity tests suggest that the dominant contribution to travel time residuals calculated from information provided in global bulletins is location and picks errors, not travel time prediction errors due to 3-D structure. Modeling the whole multiple-event system results in accurate locations and an internally consistent data set that is ideal for tomography and other travel time calibration studies. Simmons et al. (2011) (companion paper) use the Bayesloc-processed data set to develop a 3-D tomographic image, which further reduces residual standard deviation to 0.50 s.

  19. S-P wave travel time residuals and lateral inhomogeneity in the mantle beneath Tibet and the Himalaya

    NASA Technical Reports Server (NTRS)

    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.

  20. Location Algorithms and Errors in Time-of-Arrival Systems

    SciTech Connect

    AARONSON, EUGENE A.

    2001-09-01

    This report describes least squares solution methods and linearized estimates of solution errors caused by data errors. These methods are applied to event locating systems which use time-of-arrival (TOA) data. Analyses are presented for algorithms that use the TOA data in a ''direct'' manner and for algorithms utilizing Time-of-arrival Squared (TSQ) methods. Location and error estimation results were applied to a ''typical'' satellite TOA detecting system. Using Monte Carlo methods, it was found that the linearized location error estimates were valid for random data errors with relatively large variances and relatively poor event/sensor geometries. In addition to least squares methods, which use an L{sub 2} norm, methods were described for L{sub 1} and L{sub {infinity}} norms. In general, these latter norms offered little improvement over least squares methods. Reduction of the location error variances can be effected by using information in addition to the TOA data themselves by adding judiciously chosen ''conditioning'' equation(s) to the least squares system. However, the added information can adversely affect the mean errors. Also, conditioned systems may offer location solutions where nonconditioned scenarios may not be solvable. Solution methods and linearized error estimates are given for ''conditioned'' systems. It was found that for significant data errors, the linearized estimates were also close to the Monte Carlo results.

  1. P-wave travel-time tomography reveals multiple mantle upwellings beneath the northern East-Africa Rift

    NASA Astrophysics Data System (ADS)

    Hammond, J. O. S.; Civiero, C.; Goes, S. D. B.; Ahmed, A.; Ayele, A.; Doubre, C.; Goitom, B.; Keir, D.; Kendall, M.; Leroy, S. D.; Ogubazghi, G.; Rumpker, G.; Stuart, G. W.

    2014-12-01

    The East African Rift (EAR) shows evidence for active magmatism from the eruption of flood basalts 30 Ma to active volcanism associated with rifting today. Mantle plumes have been invoked as the likely cause. However, the nature of mantle upwelling is debated, with proposed models ranging from a single broad plume, the African Superplume, connected to the LLSVP beneath Southern Africa, to multiple distinct sources of upwelling along the East-Africa Rift. We present a new relative travel-time tomography model that images detailed P-wave velocities below the northern East-African rift from the surface to lower mantle depths. Data comes from 439 stations that cover the area from Tanzania to Saudi Arabia. The aperture of the integrated dataset allows us to image for the first time low-velocity structures of ~ 100-km length scales down to depths of 900 km beneath this region. Our images provide evidence of at least two separate low-velocity structures with a diameter of ~200 km that continue through the transition zone and into the lower mantle: the first, and most pronounced, is beneath the Afar Depression, which extends to at least 900 km depth and a second is located beneath the Main Ethiopian Rift that extends to at least 750 km. Taking into account seismic sensitivity to temperature and thermally controlled phase boundary topography, we interpret these features as multiple focused upwellings from below the transition zone with excess temperatures of ~ 100-150 K. Such temperatures are also fully consistent with previous petrological and other geophysical estimates. Furthermore, the separate structures could explain differences in geochemistry of erupted magmas along the rift zone, as well as the dynamic topography seen at the surface. Our findings thus support the involvement of multiple plumes in the evolution of the EAR and a direct connection between lower mantle features and the volcanism at the surface.

  2. Uppermost mantle P wave velocities beneath Turkey and Iran

    SciTech Connect

    Chen, C.; Chen, W.; Molnar, P.

    1980-01-01

    The uppermost mantle P wave velocities beneath Turkey and Iran were estimated by applying the conventional travel time-distance relation method to arrival times of well located earthquakes recorded at a few stations. The average uppermost mantle P wave velocity under Turkey is estimated from two stations of the World Wide Standardized Seismograph Network (WWSSN), Istanbul and Tabriz. The data are consistent with a crust of uniform, but poorly determined, thickness and an uppermost mantle P wave velocity of 7.73 +- 0.08 km/s. This velocity is very similar to that for the Aegean Sea and suggests that its structure could be closely related to that beneath Turkey. For Iran, the results calculated from travel times to three WWSSN stations, Meshed, Shiraz, and Tabriz, can be explained by a crust dipping toward the south-southeast at about 1/sup 0/ with an uppermost mantle P wave velocity of 8.0 +- 0.1 km/s. If the crustal thickness were 34 km in the north it would reach about 49 km in the south. Based on these uppermost mantle velocities, the temperature at Moho beneath Turkey is probably close to the melting temperature of peridotite but that beneath Iran is probably lower.

  3. A simple approach to estimate earthquake magnitude from the arrival time of the peak acceleration amplitude

    NASA Astrophysics Data System (ADS)

    Noda, S.; Yamamoto, S.

    2014-12-01

    In order for Earthquake Early Warning (EEW) to be effective, the rapid determination of magnitude (M) is important. At present, there are no methods which can accurately determine M even for extremely large events (ELE) for EEW, although a number of the methods have been suggested. In order to solve the problem, we use a simple approach derived from the fact that the time difference (Top) from the onset of the body wave to the arrival time of the peak acceleration amplitude of the body wave scales with M. To test this approach, we use 15,172 accelerograms of regional earthquakes (most of them are M4-7 events) from the K-NET, as the first step. Top is defined by analyzing the S-wave in this step. The S-onsets are calculated by adding the theoretical S-P times to the P-onsets which are manually picked. As the result, it is confirmed that logTop has high correlation with Mw, especially for the higher frequency band (> 2Hz). The RMS of residuals between Mw and M estimated in this step is less than 0.5. In case of the 2011 Tohoku earthquake, M is estimated to be 9.01 at 150 seconds after the initiation of the event.To increase the number of the ELE data, we add the teleseismic high frequency P-wave records to the analysis, as the second step. According to the result of various back-projection analyses, we consider the teleseismic P-waves to contain information on the entire rupture process. The BHZ channel data of the Global Seismographic Network for 24 events are used in this step. 2-4Hz data from the stations in the epicentral distance range of 30-85 degrees are used following the method of Hara [2007]. All P-onsets are manually picked. Top obtained from the teleseimic data show good correlation with Mw, complementing the one obtained from the regional data. We conclude that the proposed approach is quite useful for estimating reliable M for EEW, even for the ELE.

  4. Semi-coherent time of arrival estimation using regression.

    PubMed

    Apartsin, Alexander; Cooper, Leon N; Intrator, Nathan

    2012-08-01

    Time of arrival (ToA) estimation is essential for many types of remote sensing applications including radar, sonar, and underground exploration. The standard method for ToA estimation employs a matched filter for computing the maximum likelihood estimator (MLE) for ToA. The accuracy of the MLE decreases rapidly whenever the amount of noise in a received signal rises above a certain threshold. This well-known threshold effect is unavoidable in several important applications due to various limitations on the power and the spectrum of a narrowband source pulse. A measurement performed in the presence of the threshold effect employs a receiver which operates in the semi-coherent state. Therefore, the conventional methods assuming a coherent state receiver should be adapted to the semi-coherent case. In this paper, a biosonar-inspired method for the semi-coherent ToA estimation is described. The method abandons the exploration of an echo signal by a single matched filter in favor of the analysis by multiple phase-shifted unmatched filters. Each phase-shifted unmatched filter gives rise to a biased ToA estimator. The described method uses regression for combining these estimators into a single unbiased ToA estimator that outperform the MLE in the presence of the threshold effect. PMID:22894206

  5. A Fast-Time Simulation Tool for Analysis of Airport Arrival Traffic

    NASA Technical Reports Server (NTRS)

    Erzberger, Heinz; Meyn, Larry A.; Neuman, Frank

    2004-01-01

    The basic objective of arrival sequencing in air traffic control automation is to match traffic demand and airport capacity while minimizing delays. The performance of an automated arrival scheduling system, such as the Traffic Management Advisor developed by NASA for the FAA, can be studied by a fast-time simulation that does not involve running expensive and time-consuming real-time simulations. The fast-time simulation models runway configurations, the characteristics of arrival traffic, deviations from predicted arrival times, as well as the arrival sequencing and scheduling algorithm. This report reviews the development of the fast-time simulation method used originally by NASA in the design of the sequencing and scheduling algorithm for the Traffic Management Advisor. The utility of this method of simulation is demonstrated by examining the effect on delays of altering arrival schedules at a hub airport.

  6. A COMPARISON OF COLLAPSING AND PRECISE ARRIVAL-TIME MAPPING OF MICROSEISMICITY

    SciTech Connect

    RUTLEDGE, JAMES T.; JONES, ROB H.

    2007-01-05

    In this paper they compare the improvements in microseismic location images obtained using precise arrival times with that obtained by the collapsing technique. They first collapse the initial locations for a hydraulic-fracture data set from the Carthage Cotton Valley gas field, they then use the precise-arrival-time locations as measure for the effectiveness of the collapsing. Finally, they examine the changes when applying collapsing to the precise-arrival-time locations.

  7. The calculation of mean first arrival time for double mutants, crossing the fitness valley

    NASA Astrophysics Data System (ADS)

    Saakian, David B.

    2015-05-01

    We calculated the mean first arrival time of the new double mutant in the Wright-Fisher and Moran models with selection where N is the population size, the mutation probability scales as 1/N and selection coefficient as 1/\\sqrt{N} . We mapped the mean first arrival time problem into Kummer equation. Our results have a O(1/\\sqrt{N}) relative accuracy. Our analytic result is rather universal, it describes the mean first arrival time in these models.

  8. Grid travel{time tracing: second{order method for the rst arrivals in smooth media

    E-print Network

    Cerveny, Vlastislav

    Grid travel{time tracing: second{order method for the #12;rst arrivals in smooth media Lud#20;ek{arrival travel times on a rectan- gular grid of points is proposed. The new proposed method is of second{order accuracy. This means that the error of the calculated travel time is proportional to the second power

  9. Grid travel{time tracing: second{order method for the rst arrivals in smooth media *

    E-print Network

    Cerveny, Vlastislav

    Grid travel{time tracing: second{order method for the #12;rst arrivals in smooth media * Lud#20;ek the #12;rst{arrival travel times on a rectangular grid of points is proposed. Whereas the former "#12;nite is of the second{order accu- racy. It means that the relative propagation{velocity error of calculated travel time

  10. Timing the Random and Anomalous Arrival of Particles in a Geiger Counter with GPS Devices

    ERIC Educational Resources Information Center

    Blanco, F.; La Rocca, P.; Riggi, F.; Riggi, S.

    2008-01-01

    The properties of the arrival time distribution of particles in a detector have been studied by the use of a small Geiger counter, with a GPS device to tag the event time. The experiment is intended to check the basic properties of the random arrival time distribution between successive events and to simulate the investigations carried out by…

  11. A discrete-time Markov modulated queuing system with batched arrivals

    E-print Network

    Clegg, Richard G.

    to existing work in queuing theory. In section 3 the model is solved to get equations for the expected queueA discrete-time Markov modulated queuing system with batched arrivals Richard G. Clegg Department a discrete-time queuing system with applications to telecom- munications traffic. The arrival process

  12. Joint Inversion of Geoid Anomaly and Teleseismic P-Wave Delay Times: Modeling Density and Velocity Perturbations Beneath the Parana Magmatic Province

    NASA Astrophysics Data System (ADS)

    Chaves, C. A. M.; Ussami, N.; Ritsema, J.

    2014-12-01

    The Parana Magmatic Province (PMP) is one of the largest continental igneous provinces (LIP) on Earth. It is well dated at 133 Ma preceding the opening of the South Atlantic Ocean, but the causative geodynamic processes are still poorly understood. Although a low-velocity anomaly has been imaged by seismic tomography in the northeast region of the PMP and interpreted as a fossil conduct of a mantle plume that is related to the flood basalt eruptions, geochemical data indicate that such magmatism is caused by the melting of a heterogeneous and enriched lithospheric mantle with no deep plume participation. Models of density perturbations in the upper mantle estimated from joint inversion of geoid anomalies and P-wave delay times will offer important constraints on mantle dynamics. A new generation of accurate global geopotential models derived from satellite-missions (e.g. GRACE, GOCE) allows us to estimate density distribution within the Earth from geoid inversion. In order to obtain the residual geoid anomaly related to the density structure of the mantle, we use the EGM2008 model removing estimated geoid perturbations owing to variations in crustal structure (i.e., topographical masses, Moho depth, thickness of sediments and basalts). Using a spherical-Earth approximation, the density model space is represented by a set of tesseroids and the velocity model is parameterized in nodes of a spherical grid where cubic B-splines are utilized as an interpolation function. To constrain the density inversion, we add more than 10,000 manually picked teleseismic P-wave delay times. During the inversion procedure, density and P-wave velocity are linked through the optimization of a constant linear factor correlating density and velocity perturbation. Such optimization will be performed using a probability density function (PDF) [Tarantola, 2005]. We will present the preliminary results of this joint inversion scheme and hypothesize on the geodynamic processes responsible for the flood basalt eruptions.

  13. Perturbation analysis of queueing systems with a time-varying arrival rate

    NASA Technical Reports Server (NTRS)

    Cassandras, Christos G.; Pan, Jie

    1991-01-01

    The authors consider an M/G/1 queuing with a time-varying arrival rate. The objective is to obtain infinitesimal perturbation analysis (IPA) gradient estimates for various performance measures of interest with respect to certain system parameters. In particular, the authors consider the mean system time over n arrivals and an arrival rate alternating between two values. By choosing a convenient sample path representation of this system, they derive an unbiased IPA gradient estimator which, however, is not consistent, and investigate the nature of this problem.

  14. Ready...Go: Amplitude of the fMRI Signal Encodes Expectation of Cue Arrival Time

    E-print Network

    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

  15. Foraging under competition: evolutionarily stable patch-leaving strategies with random arrival times.

    E-print Network

    Nain, Philippe

    as a solution of an implicit equation, independent of the distribution law of arrival times. A digression is applied to a lone forager that has monopoly on resources it finds; it predicts that each patch should

  16. A note on some statistical properties of rise time parameters used in muon arrival time measurements

    NASA Technical Reports Server (NTRS)

    Vanderwalt, D. J.; Devilliers, E. J.

    1985-01-01

    Most investigations of the muon arrival time distribution in EAS during the past decade made use of parameters which can collectively be called rise time parameters. The rise time parameter T sub A/B is defined as the time taken for the integrated pulse from a detector to rise from A% to B% of its full amplitude. The use of these parameters are usually restricted to the determination of the radial dependence thereof. This radial dependence of the rise time parameters are usually taken as a signature of the particle interaction characteristics in the shower. As these parameters have a stochastic nature, it seems reasonable that one should also take notice of this aspect of the rise time parameters. A statistical approach to rise time parameters is presented.

  17. Lithospheric structure of the Illinois Basin from teleseismic P-wave tomography

    NASA Astrophysics Data System (ADS)

    Wilson, B.; Gilbert, H. J.; Hamburger, M. W.; Merrell, T.; Pavlis, G. L.; Sherrill, E.

    2013-12-01

    We examine heterogeneity of the crust and upper mantle associated with a major intracratonic basin, using arrival time data from a regional EarthScope experiment extending across the western margin of the Illinois Basin. We measured 24,062 P-wave residuals associated with 399 teleseismic events recorded from January 2012 to March 2013 by 122 stations in the Illinois Basin region. We used data from the Ozark Illinois INdiana Kentucky (OIINK) Flexible Array, the permanent New Madrid Seismic Network, and a portion of the Earthscope Transportable Array. Precise relative arrival times were determined using array cross-correlation methods. We plotted the measured arrivals as residual maps to identify first order patterns of velocity heterogeneity and to fix outliers. These data were then inverted for P-wave velocity using non-linear tomography code developed by Steven Roecker. Our preliminary results indicate the upper 200 km of the mantle can be characterized by two blocks with a transition zone centered roughly parallel to the Ohio River boundary of Illinois and Kentucky. Estimated P-wave velocities are higher in Kentucky, located southeast of the transition zone compared to Missouri and Illinois, located northwest. We caution that at this stage our tomography model may be biased as we have not accounted for variations in crustal structure or applied corrections associated with the Illinois Basin. Parallel work with receiver functions by our group and the known geometry of the Illinois Basin will be used to calculate these corrections and modify the tomographic model accordingly.

  18. A Fast-Time Study of Aircraft Reordering in Arrival Sequencing and Scheduling

    NASA Technical Reports Server (NTRS)

    Carr, Greg; Neuman, Frank; Tobias, Leonard (Technical Monitor)

    1998-01-01

    In order to ensure that the safe capacity of the terminal area is not exceeded, Air Traffic Management ATM often places restrictions on arriving flights transitioning from en route airspace to terminal airspace. This restriction of arrival traffic is commonly referred to as arrival flow management, and includes techniques such as metering, vectoring, fix-load balancing, and the imposition of miles-in-trail separations. These restrictions are enacted without regard for the relative priority which airlines may be placing on individual flights based on factors such as crew criticality, passenger connectivity, critical turn times, gate availability, on-time performance, fuel status, or runway preference. The development of new arrival flow management techniques which take into consideration priorities expressed by air carriers will likely reduce the economic impact of ATM restrictions on the airlines and lead to increased airline economic efficiency by allowing airlines to have greater control over their individual arrival banks of aircraft. NASA and the Federal Aviation Administration (FAA) have designed and developed a suite of software decision support tools (DSTs) collectively known as the Center TRACON Automation System (CTAS). One of these tools, the Traffic Management Advisor (TMA) is currently being used at the Fort Worth Air Route Traffic Control Center to perform arrival flow management of traffic into the Dallas/Fort Worth airport (DFW). The TMA is a time-based strategic planning tool that assists Traffic Management Coordinators (TMCs) and En Route Air Traffic Controllers in efficiently balancing arrival demand with airport capacity. The primary algorithm in the TMA is a real-time scheduler which generates efficient landing sequences and landing times for arrivals within about 200 no a. from touchdown. This scheduler will sequence aircraft so that they arrive in a first- come - first-served (FCFS) order. While FCFS sequencing establishes a fair order based on estimated times of arrival, it does not take into account individual airline priorities among incoming flights. NASA is exploring the possibility of allowing airlines to express relative arrival priorities to air traffic management through the development of new CTAS scheduling algorithms which take into consideration airline arrival preferences. The accommodation of airline priorities in arrival sequencing and scheduling would under most circumstances result in a deviation from a "natural" or FCFS arrival order. As a First step toward developing airline influenced sequencing algorithms, an investigation was conducted to determine the feasibility of reordering arrival traffic from a strict FCFS sequence. A fast-time simulation has been developed which allows statistical evaluation of sequencing and scheduling algorithms for arrival traffic at the Dallas/Fort Worth Airport. In contrast to real-time simulation or field tests, which would require on the order of ninety minutes to examine a single traffic rush period, the fast-time simulation allows examination of multiple rush periods in a matter of seconds.

  19. The PDV Velocity History and Shock Arrival Time Analyzer

    Energy Science and Technology Software Center (ESTSC)

    2006-08-29

    This software allows the user to analyze heterodyne beat signals generated when a Doppler-shifted laser light interacts with un-shifted laser light. The software analyzes the data in a joint time frequency domain to extract instantaneous velocity.

  20. Scaling Behavior of the First Arrival Time of a Random-Walking Magnetic Domain

    SciTech Connect

    Im, M.-Y.; Lee, S.-H.; Kim, D.-H.; Fischer, P.; Shin, S.-C.

    2008-02-04

    We report a universal scaling behavior of the first arrival time of a traveling magnetic domain wall into a finite space-time observation window of a magneto-optical microscope enabling direct visualization of a Barkhausen avalanche in real time. The first arrival time of the traveling magnetic domain wall exhibits a nontrivial fluctuation and its statistical distribution is described by universal power-law scaling with scaling exponents of 1.34 {+-} 0.07 for CoCr and CoCrPt films, despite their quite different domain evolution patterns. Numerical simulation of the first arrival time with an assumption that the magnetic domain wall traveled as a random walker well matches our experimentally observed scaling behavior, providing an experimental support for the random-walking model of traveling magnetic domain walls.

  1. Scaling behavior of the first arrival time of a random-walking magnetic domain.

    PubMed

    Im, M-Y; Lee, S-H; Kim, D-H; Fischer, P; Shin, S-C

    2008-04-25

    We report a universal scaling behavior of the first arrival time of a traveling magnetic domain wall into a finite space-time observation window of a magneto-optical microscope enabling direct visualization of a Barkhausen avalanche in real time. The first arrival time of the traveling magnetic domain wall exhibits a nontrivial fluctuation and its statistical distribution is described by universal power-law scaling with scaling exponents of 1.34+/-0.07 for CoCr and CoCrPt films, despite their quite different domain evolution patterns. Numerical simulation of the first arrival time with an assumption that the magnetic domain wall traveled as a random walker well matches our experimentally observed scaling behavior, providing an experimental support for the random-walking model of traveling magnetic domain walls. PMID:18518241

  2. Does winter region affect spring arrival time and body mass of king eiders in northern Alaska?

    USGS Publications Warehouse

    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.

  3. Continuous measurement of the arrival times of x-ray photon sequence

    SciTech Connect

    Yan Qiurong; Sheng Lizhi; Zhao Baosheng; Liu Yong'an

    2011-05-15

    In order to record x-ray pulse profile for x-ray pulsar-based navigation and timing, this paper presents a continuous, high-precision method for measuring arrival times of photon sequence with a common starting point. In this method, a high stability atomic clock is counted to measure the coarse time of arrival photon. A high resolution time-to-digital converter is used to measure the fine time of arrival photon. The coarse times and the fine times are recorded continuously and then transferred to computer memory by way of memory switch. The pulse profile is obtained by a special data processing method. A special circuit was developed and a low-level x-ray pulse profile measurement experiment system was setup. The arrival times of x-ray photon sequence can be consecutively recorded with a time resolution of 500 ps and the profile of x-ray pulse was constructed. The data also can be used for analysis by many other methods, such as statistical distribution of photon events per time interval, statistical distribution of time interval between two photon events, photon counting histogram, autocorrelation and higher order autocorrelation.

  4. Multi-Mode Lamb Wave Arrival Time Extraction for Improved Tomographic Reconstruction

    SciTech Connect

    Hinders, Mark K.; Hou Jidong; Leonard, Kevin R.

    2005-04-09

    An ultrasonic signal processing technique is applied to multi-mode arrival time estimation from Lamb waveforms. The basic tool is a simplified time-scale projection called a dynamic wavelet fingerprint (DWFP) which enables direct observation of the variation of features of interest in non-stationary ultrasonic signals. The DWFP technique was used to automatically detect and evaluate each candidate through-transmitted Lamb mode. The area of the dynamic wavelet fingerprint was then used as a feature to distinguish false modes caused by noise and other interference from the true modes of interest. The set of estimated arrival times were then used as inputs for tomographic reconstruction. The Lamb wave tomography images generated with these estimated arrival times were able to indicate different defects in aluminum plates.

  5. EFFECTS OF REFRACTION ON ANGLES AND TIMES OF ARRIVAL OF SOLAR RADIO BURSTS

    SciTech Connect

    Thejappa, G.; MacDowall, R. J.; Gopalswamy, N. E-mail: Robert.MacDowall@nasa.gov

    2011-06-10

    Solar type III and type II radio bursts suffer severe bending and group delay due to refraction while escaping from the source where the refractive index {mu} can be as low as {approx}0 to the observer where {mu} {approx} 1. These propagation effects can manifest themselves as errors in the observed directions and times of arrival at the telescope. We describe a ray-tracing technique that can be used to estimate these errors. By applying this technique to the spherically symmetric density model derived using the data from the WIND/Waves experiment, we show that (1) the fundamental and harmonic emissions escape the solar atmosphere in narrow cones (at 625 kHz the widths of these escape cones are {approx}1.{sup 0}1 and {approx}8{sup 0}, respectively), (2) the errors in the angles as well as the times of arrival increase monotonically with the angle of arrival (at 625 kHz these errors are 0.{sup 0}26 and {approx}17.2 s for the fundamental and {approx}0.{sup 0}52 and {approx}7.6 s for the harmonic at the maximum possible angles of arrival of {approx}0.{sup 0}55 and {approx}4{sup 0}, respectively), and (3) the lower the frequencies are, the higher the errors in both the angles and times of arrival are. This implies that at 625 kHz the measured arrival angles and arrival times of the fundamental and harmonic are off by {approx}50% and {approx}13%, and {approx}3.4% and {approx}1.5%, respectively.

  6. Improvements of the shock arrival times at the Earth model STOA

    E-print Network

    Liu, H -L

    2015-01-01

    Prediction of the shocks' arrival times (SATs) at the Earth is very important for space weather forecast. There is a well-known SAT model, STOA, which is widely used in the space weather forecast. However, the shock transit time from STOA model usually has a relative large error compared to the real measurements. In addition, STOA tends to yield too much `yes' prediction, which causes a large number of false alarms. Therefore, in this work, we work on the modification of STOA model. First, we give a new method to calculate the shock transit time by modifying the way to use the solar wind speed in STOA model. Second, we develop new criteria for deciding whether the shock will arrive at the Earth with the help of the sunspot numbers and the angle distances of the flare events. It is shown that our work can improve the SATs prediction significantly, especially the prediction of flare events without shocks arriving at the Earth.

  7. The prediction of bus arrival time using Automatic Vehicle Location Systems data 

    E-print Network

    Jeong, Ran Hee

    2005-02-17

    , schedule adherence by time period, and traffic congestion which were critical to predict accurate bus arrival times. The test bed was a bus route running in the downtown of Houston, Texas. A historical based model, regression models, and artificial.................................................................5 1.3.2 Collect Data and Define Test Bed......................................................5 1.3.3 Reduce Data and Correct Errors ........................................................5 1...

  8. Scattering by a reflectionless modified Pöschl-Teller potential: Bohmian trajectories and arrival times

    NASA Astrophysics Data System (ADS)

    Mousavi, S. V.

    2015-09-01

    A nonreflecting wavepacket is constructed by the superposition of reflectionless eigenstates of modified Pöschl-Teller potential. Free propagation and propagation in the presence of the above potential of such a wavepacket is considered using the concept of arrival time. Comparison is made with the free evolving Gaussian wavepacket. Mean arrival time at a detector behind the well is given as a function of mass for separate cases. A selection of Bohmian trajectories in the interacting case are computed and compared to the trajectories of a free particle guided by a Gaussian packet.

  9. Time-of-Arrival Lightning Location Retrieval Using an Oblate Spheroidal Earth Model

    NASA Technical Reports Server (NTRS)

    Solakiewicz, Richard

    1999-01-01

    The problem of retrieving lightning ground strike location on an oblate spheroidal Earth using a network of 4 or more time-of-arrival sensors is considered. A recently developed analytic method for obtaining such retrievals on a spherical Earth surface is perturbed resulting in an iterative procedure to get correction terms. The perturbation procedure consists of applying a vector Newton's method to eqs. relating the distances from the lightning location to each sensor along a geodesic and the times of arrival of the wave produced by the lightning source at each sensor.

  10. Changes in the timing of departure and arrival of Irish migrant waterbirds

    PubMed Central

    Geyer, Heather; Yu, Rong

    2015-01-01

    There have been many recent reports across Europe and North America of a change in the timing of arrival and departure of a range of migrant bird species to their breeding grounds. These studies have focused primarily on passerine birds and climate warming has been found to be one of the main drivers of earlier arrival and departure in spring. In Ireland, rising spring temperature has been shown to result in the earlier arrival of sub-Saharan passerine species and the early departure of the Whooper Swan. In order to investigate changes in spring arrival and departure dates of waterbirds to Ireland, we extracted latest dates as an indicator of the timing of departure of winter visitors (24 species) and earliest dates as an indicator of the timing of arrival of spring/summer migrants (2 species) from BirdWatch Ireland’s East Coast Bird reports (1980–2003). Three of the winter visitors showed evidence of later departure and one of earlier departure whereas one of the spring/summer visitors showed evidence of earlier arrival. In order to determine any influence of local temperature on these trends, we analysed data from two synoptic weather stations within the study area and found that spring (average February, March and April) air temperature significantly (P < 0.05) increased at a rate of 0.03 °C per year, which was strongly correlated with changes in latest and earliest records. We also tested the sensitivity of bird departure/arrival to temperature and found that Northern Pintail would leave 10 days earlier in response to a 1 °C increase in spring temperature. In addition, we investigated the impact of a large-scale circulation pattern, the North Atlantic Oscillation (NAO), on the timing of arrival and departure which correlated with both advances and delays in departure and arrival. We conclude that the impact of climate change on earliest and latest records of these birds is, as expected, species specific and that local temperature had less of an influence than large-scale circulation patterns. PMID:25653907

  11. OneBusAway: Results from Providing Real-Time Arrival Information for Public Transit

    E-print Network

    Washington at SeattleUniversity of

    OneBusAway: Results from Providing Real-Time Arrival Information for Public Transit Brian Ferris@cs.washington.edu ABSTRACT Public transit systems play an important role in combating traffic congestion, reducing carbon emissions, and promot- ing compact, sustainable urban communities. The usability of public transit can

  12. Improvements of the shock arrival times at the Earth model STOA

    NASA Astrophysics Data System (ADS)

    Liu, H.-L.; Qin, G.

    2015-07-01

    Prediction of the shocks' arrival times (SATs) at the Earth is very important for space weather forecast. There is a well-known SAT model, Shock Time of Arrival (STOA), which is widely used in the space weather forecast. However, the shock transit time from STOA model usually has a relative large error compared to the real measurements. In addition, STOA tends to yield too much "yes" prediction, which causes a large number of false alarms. Therefore, in this work, we work on the modification of STOA model. First, we give a new method to calculate the shock transit time by modifying the way to use the solar wind speed in STOA model. Second, we develop new criteria for deciding whether the shock will arrive at the Earth with the help of the sunspot numbers and the angle distances of the flare events. It is shown that our work can improve the SATs prediction significantly, especially the prediction of flare events without shocks arriving at the Earth.

  13. HE 2.2.43 1 EAS Muon Arrival Time Distributions Measured in the

    E-print Network

    Hörandel, Jörg R.

    HE 2.2.43 1 EAS Muon Arrival Time Distributions Measured in the KASCADE Experiment I.M. Brancus 1, Lodz, Poland Abstract The temporal structure of the EAS muon component, given by median, first and third quartile of the single distributions is studied with the muon detection facilities of the KASCADE

  14. Robust Tracking of a Mobile Beacon using Time Differences of Arrival with Simultaneous

    E-print Network

    Teschner, Matthias

    Robust Tracking of a Mobile Beacon using Time Differences of Arrival with Simultaneous Calibration. In this paper, we consider calibration-free tracking of a mobile beacon using TDOA, i.e., the positions localize the signal beacon and the receivers. Our method is robust against measurement outliers

  15. Pricing-Based Strategies for Autonomic Control of Web Servers for Time-Varying Request Arrivals

    E-print Network

    Gautam, Natarajan

    automatically tune themselves. As business enterprises and individual users become increasingly dependentPricing-Based Strategies for Autonomic Control of Web Servers for Time-Varying Request Arrivals on the varying conditions, both internally and externally. It has developed revenue-based pricing as well

  16. Optimal Time Advance In Terminal Area Arrivals: Throughput vs. Fuel Savings

    NASA Technical Reports Server (NTRS)

    Sadovsky, Alexander V .; Swenson, Harry N.; Haskell, William B.; Rakas, Jasenka

    2011-01-01

    The current operational practice in scheduling air traffic arriving at an airport is to adjust flight schedules by delay, i.e. a postponement of an aircrafts arrival at a scheduled location, to manage safely the FAA-mandated separation constraints between aircraft. To meet the observed and forecast growth in traffic demand, however, the practice of time advance (speeding up an aircraft toward a scheduled location) is envisioned for future operations as a practice additional to delay. Time advance has two potential advantages. The first is the capability to minimize, or at least reduce, the excess separation (the distances between pairs of aircraft immediately in-trail) and thereby to increase the throughput of the arriving traffic. The second is to reduce the total traffic delay when the traffic sample is below saturation density. A cost associated with time advance is the fuel expenditure required by an aircraft to speed up. We present an optimal control model of air traffic arriving in a terminal area and solve it using the Pontryagin Maximum Principle. The admissible controls allow time advance, as well as delay, some of the way. The cost function reflects the trade-off between minimizing two competing objectives: excess separation (negatively correlated with throughput) and fuel burn. A number of instances are solved using three different methods, to demonstrate consistency of solutions.

  17. Effective evacuation route planning algorithms by updating earliest arrival time of multiple paths

    E-print Network

    Lim, Sunho

    Effective evacuation route planning algorithms by updating earliest arrival time of multiple paths are happening around the globe and in such urgent situations, effective evacuation planning is one of the most critical tools for human safety. Evacuation planning algorithms are different from traditional network

  18. Maximum Likelihood Time-of-Arrival Estimation of Optical Pulses via Photon-Counting Photodetectors

    NASA Technical Reports Server (NTRS)

    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.

  19. Linear Time-of-Arrival Estimation in a Multipath Environment by Inverse Correlation Method

    E-print Network

    Stanford University

    ), the multipath error remains as a single dominant source of the positioning error. Therefore the mitigation of the multipath error is pursued extensively and various efforts have been made to estimate a multipath channelLinear Time-of-Arrival Estimation in a Multipath Environment by Inverse Correlation Method Ju

  20. Techniques for measuring arrival times of pulsar signals 1: DSN observations from 1968 to 1980

    NASA Technical Reports Server (NTRS)

    Downs, G. S.; Reichley, P. E.

    1980-01-01

    Techniques used in the ground based observations of pulsars are described, many of them applicable in a navigation scheme. The arrival times of the pulses intercepting Earth are measured at time intervals from a few days to a few months. Low noise, wide band receivers, amplify signals intercepted by 26 m, 34, and 64 m antennas. Digital recordings of total received signal power versus time are cross correlated with the appropriate pulse template.

  1. From 3-Hz P Waves to 0-S-2: Real-time and deferred estimates of the moment of the Honshu event across the full frequency spectrum

    NASA Astrophysics Data System (ADS)

    Andre, O. E.

    2011-12-01

    In the hours following the 2011 Honshu event, and as part of tsunami warning procedures at the Laboratoire de Geophysique in Papeete, Tahiti, the seismic source of the event was analyzed using a number of real-time procedures. The ultra-long period mantle magnitude algorithm suggests a static moment of 4.2E29 dyn*cm, not signifcantly different from the NEIC value obtained by W-phase inversion. The slowness parameter, THETA = -5.65, is slightly deficient, but characteristic of other large subduction events such as Nias (2005) or Peru (2001); it remains significantly larger than for slow earthquakes such as Sumatra (2004) or Mentawai (2010). Similarly, the duration of high-frequency (2-4 Hz) P waves in relation to seismic moment or estimated energy fails to document any slowness in the seismic source. These results were confirmed in the ensuing weeks by the analysis of the lowest-frequency spheroidal modes of the Earth. A dataset of 109 fits for 8 modes (including the gravest one, 0s2, and the breathing mode, 0s0) yields a remarkably flat spectrum, with an average moment of 3.5E29 dyn*cm (*/1.07). This textbook behavior of the Sendai earthquake explains the generally successful real-time modeling of its teleseismic tsunami, based on available seismic source scaling laws. On the other hand, it confirms the dichotomy, amongst mega-quakes (M sub 0 > 10 sup 29 dyn*cm) between regular events (Nias, 2005; Chile, 2010; Sendai, 2011) and slow ones (Chile, 1960; Alaska, 1964; Sumatra, 2004; and probably Rat Island, 1965), whose origin remains unexplained.

  2. Monitoring molecular interactions using photon arrival-time interval distribution analysis

    DOEpatents

    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.

  3. Multiple mantle upwellings in the transition zone beneath the northern East-African Rift system from relative P-wave travel-time tomography

    NASA Astrophysics Data System (ADS)

    Civiero, Chiara; Hammond, James O. S.; Goes, Saskia; Fishwick, Stewart; Ahmed, Abdulhakim; Ayele, Atalay; Doubre, Cecile; Goitom, Berhe; Keir, Derek; Kendall, J.-Michael; Leroy, Sylvie; Ogubazghi, Ghebrebrhan; Rümpker, Georg; Stuart, Graham W.

    2015-09-01

    Mantle plumes and consequent plate extension have been invoked as the likely cause of East African Rift volcanism. However, the nature of mantle upwelling is debated, with proposed configurations ranging from a single broad plume connected to the large low-shear-velocity province beneath Southern Africa, the so-called African Superplume, to multiple lower-mantle sources along the rift. We present a new P-wave travel-time tomography model below the northern East-African, Red Sea, and Gulf of Aden rifts and surrounding areas. Data are from stations that span an area from Madagascar to Saudi Arabia. The aperture of the integrated data set allows us to image structures of ˜100 km length-scale down to depths of 700-800 km beneath the study region. Our images provide evidence of two clusters of low-velocity structures consisting of features with diameter of 100-200 km that extend through the transition zone, the first beneath Afar and a second just west of the Main Ethiopian Rift, a region with off-rift volcanism. Considering seismic sensitivity to temperature, we interpret these features as upwellings with excess temperatures of 100 ± 50 K. The scale of the upwellings is smaller than expected for lower mantle plume sources. This, together with the change in pattern of the low-velocity anomalies across the base of the transition zone, suggests that ponding or flow of deep-plume material below the transition zone may be spawning these upper mantle upwellings. This article was corrected on 28 SEP 2015. See the end of the full text for details.

  4. High resolution time of arrival estimation for a cooperative sensor system

    NASA Astrophysics Data System (ADS)

    Morhart, C.; Biebl, E. M.

    2010-09-01

    Distance resolution of cooperative sensors is limited by the signal bandwidth. For the transmission mainly lower frequency bands are used which are more narrowband than classical radar frequencies. To compensate this resolution problem the combination of a pseudo-noise coded pulse compression system with superresolution time of arrival estimation is proposed. Coded pulsecompression allows secure and fast distance measurement in multi-user scenarios which can easily be adapted for data transmission purposes (Morhart and Biebl, 2009). Due to the lack of available signal bandwidth the measurement accuracy degrades especially in multipath scenarios. Superresolution time of arrival algorithms can improve this behaviour by estimating the channel impulse response out of a band-limited channel view. For the given test system the implementation of a MUSIC algorithm permitted a two times better distance resolution as the standard pulse compression.

  5. A Detailed Study on the Equal Arrival Time Surface Effect in Gamma-Ray Burst Afterglows

    NASA Astrophysics Data System (ADS)

    Huang, Yong-Feng; Lu, Ye; Wong, Anna Yuen Lam; Cheng, Kwong Sang

    2007-06-01

    Due to the relativistic motion of gamma-ray burst remnant and its deceleration in the circumburst medium, the equal arrival time surfaces at any moment are not spherical, rather, they are distorted ellipsoids. This will leave some imprints in the afterglows. We study the effect of equal arrival time surfaces numerically for various circumstances, i.e., isotropic fireballs, collimated jets, density jumps and energy injection events. For each case, a direct comparison is made between including and not including the effect. For isotropic fireballs and jets viewed on axis, the effect slightly hardens the spectra and postpones the peak time of the afterglows, but does not change the shapes of the spectra and light curves significantly. In the cases of a density jump or an energy injection, the effect smears out the variations in the afterglows markedly.

  6. A Detailed Study on the Equal Arrival Time Surface Effect in Gamma-Ray Burst Afterglows

    E-print Network

    Y. F. Huang; Y. Lu; A. Y. L. Wong; K. S. Cheng

    2007-01-30

    Due to the relativistic motion of gamma-ray burst remnant and its deceleration in the circumburst medium, the equal arrival time surfaces at any moment are not spherical, but should be distorted ellipsoids. This will leave some imprints in the afterglows. In this article, we study the effect of equal arrival time surfaces numerically under various conditions, i.e., for isotropic fireballs, collimated jets, density jump conditions, and energy injection events. For each condition, direct comparison between the two instances when the effect is and is not included, is presented. For isotropic fireballs and jets viewed on axis, the effect slightly hardens the spectra and postpones the peak time of afterglows, but does not change the shapes of the spectra and light curves significantly. In the cases when a density jump or an energy injection is involved, the effect smears the variability of the afterglows markedly.

  7. A Comparison of Center/TRACON Automation System and Airline Time of Arrival Predictions

    NASA Technical Reports Server (NTRS)

    Heere, Karen R.; Zelenka, Richard E.

    2000-01-01

    Benefits from information sharing between an air traffic service provider and a major air carrier are evaluated. Aircraft arrival time schedules generated by the NASA/FAA Center/TRACON Automation System (CTAS) were provided to the American Airlines System Operations Control Center in Fort Worth, Texas, during a field trial of a specialized CTAS display. A statistical analysis indicates that the CTAS schedules, based on aircraft trajectories predicted from real-time radar and weather data, are substantially more accurate than the traditional airline arrival time estimates, constructed from flight plans and en route crew updates. The improvement offered by CTAS is especially advantageous during periods of heavy traffic and substantial terminal area delay, allowing the airline to avoid large predictive errors with serious impact on the efficiency and profitability of flight operations.

  8. Quantitative probing of quantum-classical transition for the arrival time distribution

    E-print Network

    Home, Dipankar; Banerjee, Arka

    2009-01-01

    The classical limit problem of quantum mechanics is revisited on the basis of a scheme that enables a quantitative study of the way the quantum-classical agreement emerges while going through the intermediate mass range between the microscopic and the macroscopic domains. As a specific application of such a scheme, we investigate the classical limit of a quantum time distribution - an area of study that has remained largely unexplored. For this purpose, we focus on the arrival time distribution in order to examine the way the observable results pertaining to the quantum arrival time distribution which is defined in terms of the probability current density gradually approach the relevant classical statistical results for an ensemble that corresponds to a Gaussian wave packet evolving in a linear potential.

  9. Impact of Day of the Week and Time of Arrival on Ischemic Stroke Management

    PubMed Central

    Rodríguez-Rivera, Ingrid V.; Santiago, Fernando; Estapé, Estela S.; Sepúlveda, Lorena González; Brau, Ricardo

    2015-01-01

    Objective The purpose of this study was to evaluate the association between measures of patient arrival day (weekday or weekend day), day part (nighttime vs. daytime) and hour (regular hours vs. off hours) at the stroke unit of the Emergency Department of the Puerto Rico Medical Center and the following time-to-treatment measures: door-to-CT-scan, door-to-needle, and stroke-onset-to-treatment. Methods In this retrospective study, the data of 54 patients was obtained from the stroke unit of the Puerto Rico Medical Center through the Get With The Guidelines-Stroke Registry. Inclusion criteria were as follows: having an ischemic stroke within the period covering from August 2008 through February 2010 and being at least 18 years old. Associations between patient arrival time and timeliness of interventions were assessed using t-tests/Mann–Whitney tests and chi-square tests/Fisher’s exact tests, as appropriate. Results The majority of the patients (74%) were men. The mean and standard deviation of age was 67 ± 14 years. The median of times for door-to-CT-scan and onset to treatment were 15 minutes (interquartile range = 15) and 2.7 hours (interquartile range = 0.6), respectively. The mean and standard deviation for door-to-needle time was 77 ± 18 minutes. No differences were found for any of the variables in terms of arrival date, day part or hour (p>0.05). The median time for door-to-CT- scan was shorter for patients receiving intravenous tissue plasminogen activator treatment than it was for those not receiving such treatment (12 minutes vs. 20 minutes; p = 0.02). Conclusions The timeliness of the stroke management interventions did not differ significantly in terms of arrival day, day part, or hour. PMID:26356742

  10. UNCERTAINTY IN PHASE ARRIVAL TIME PICKS FOR REGIONAL SEISMIC EVENTS: AN EXPERIMENTAL DESIGN

    SciTech Connect

    A. VELASCO; ET AL

    2001-02-01

    The detection and timing of seismic arrivals play a critical role in the ability to locate seismic events, especially at low magnitude. Errors can occur with the determination of the timing of the arrivals, whether these errors are made by automated processing or by an analyst. One of the major obstacles encountered in properly estimating travel-time picking error is the lack of a clear and comprehensive discussion of all of the factors that influence phase picks. This report discusses possible factors that need to be modeled to properly study phase arrival time picking errors. We have developed a multivariate statistical model, experimental design, and analysis strategy that can be used in this study. We have embedded a general form of the International Data Center(IDC)/U.S. National Data Center (USNDC) phase pick measurement error model into our statistical model. We can use this statistical model to optimally calibrate a picking error model to regional data. A follow-on report will present the results of this analysis plan applied to an implementation of an experiment/data-gathering task.

  11. Observation of arrival times of EAS with energies or = 6 x 10 (14) eV

    NASA Technical Reports Server (NTRS)

    Sun, L.

    1985-01-01

    The Earth's atmosphere is continually being bombarded by primary cosmic ray particles which are generally believed to be high-energy nuclei. The fact that the majority of cosmic ray primaries are charged particles and that space is permeated with random magnetic fields, means that the particles do not travel in straight lines. The arrival time distribution of EAS may also transfer some information about the primary particles. Actually, if the particles come to our Earth in a completely random process, the arrival time distribution of pairs of successive particles should fit an exponential law. The work reported here was arried out at Sydney University from May 1982 to January 1983. All the data are used to plot the arrival-time distribution of the events, that is, the distribution of time-separation between consecutive events on a 1 minute bin size. During this period more than 2300 showers were recorded. The results are discussed and compared with that of some other experiments.

  12. Dead on Arrival: Adapting Games to Finish at a Given Time or Location

    NASA Astrophysics Data System (ADS)

    von Öhsen, Arne; Loviscach, Jörn

    Casual and other games often serve as time-killing applications, be it on the commuter train or in the back seat of a shared car. When one arrives at the destination, the game has to be interrupted or aborted, which is annoying or even frustrating. Hence, we propose to continuously adapt the game’s level of difficulty to the estimated remaining time to arrival. This can be preset as a number of minutes or can continuously be estimated from the player’s position in relation to a predefined destination. Our dungeon-style prototype is based on an automated engine for content placement and can also make use of GPS data. We report on preliminary results from user tests.

  13. Application of Clenshaw-Curtis Method in Confined Time of Arrival Operator Eigenvalue Problem

    NASA Astrophysics Data System (ADS)

    Vitancol, Roberto S.; Galapon, Eric A.

    The Clenshaw-Curtis method in discretizing a Fredholm integral operator is applied to solving the confined time of arrival operator eigenvalue problem. The accuracy of the method is measured against the known analytic solutions for the noninteracting case, and its performance compared against the well-known Nystrom method. It is found that Clenshaw-Curtis's is superior to Nystrom's. In particular, Nystrom method yields at most five correct decimal places for the eigenvalues and eigenfunctions, while Clenshaw-Curtis yields eigenvalues correct to 16 decimal places and eigenfunctions up to 15 decimal places for the same number of quadrature points. Moreover, Clenshaw-Curtis's accuracy in the eigenvalues is uniform over a determinable range of the computed eigenvalues for a given number of quadrature abscissas. Clenshaw-Curtis is then applied to the harmonic oscillator confined time of arrival operator eigenvalue problem.

  14. Exploring the Manifold of Seismic Waves: Application to the Estimation of Arrival-Times

    E-print Network

    Kye M. Taylor; Michael J. Procopio; Christopher J. Young; Francois G. Meyer

    2010-07-22

    We propose a new method to analyze seismic time series and estimate the arrival-times of seismic waves. Our approach combines two ingredients: the times series are first lifted into a high-dimensional space using time-delay embedding; the resulting phase space is then parametrized using a nonlinear method based on the eigenvectors of the graph Laplacian. We validate our approach using a dataset of seismic events that occurred in Idaho, Montana, Wyoming, and Utah, between 2005 and 2006. Our approach outperforms methods based on singular-spectrum analysis, waveleta nalysis, and STA/LTA.

  15. Speeds and Arrival Times of Solar Transients Approximated by Self-similar Expanding Circular Fronts

    NASA Astrophysics Data System (ADS)

    Möstl, C.; Davies, J. A.

    2013-07-01

    The NASA Solar TErrestrial RElations Observatory (STEREO) mission offered the possibility to forecast the arrival times, speeds, and directions of solar transients from outside the Sun-Earth line. In particular, we are interested in predicting potentially geoeffective interplanetary coronal mass ejections (ICMEs) from observations of density structures at large observation angles from the Sun (with the STEREO Heliospheric Imager instrument). We contribute to this endeavor by deriving analytical formulas concerning a geometric correction for the ICME speed and arrival time for the technique introduced by Davies et al. ( Astrophys. J., 2012, in press), called self-similar expansion fitting (SSEF). This model assumes that a circle propagates outward, along a plane specified by a position angle ( e.g., the ecliptic), with constant angular half-width ( ?). This is an extension to earlier, more simple models: fixed-? fitting ( ?=0°) and harmonic mean fitting ( ?=90°). In contrast to previous models, this approach has the advantage of allowing one to assess clearly if a particular location in the heliosphere, such as a planet or spacecraft, might be expected to be hit by the ICME front. Our correction formulas are especially significant for glancing hits, where small differences in the direction greatly influence the expected speeds (up to 100 - 200 km s-1) and arrival times (up to two days later than the apex). For very wide ICMEs (2 ?>120°), the geometric correction becomes very similar to the one derived by Möstl et al. ( Astrophys. J. 741, 34, 2011) for the harmonic mean model. These analytic expressions can also be used for empirical or analytical models to predict the 1 AU arrival time of an ICME by correcting for effects of hits by the flank rather than the apex, if the width and direction of the ICME in a plane are known and a circular geometry of the ICME front is assumed.

  16. Crustal parameters estimated from P-waves of earthquakes recorded at a small array

    USGS Publications Warehouse

    Murdock, J.N.; Steppe, J.A.

    1980-01-01

    The P-arrival times of local and regional earthquakes that are outside of a small network of seismometers can be used to interpret crustal parameters beneath the network by employing the time-term technique. Even when the estimate of the refractor velocity is poorly determined, useful estimates of the station time-terms can be made. The method is applied to a 20 km diameter network of eight seismic stations which was operated near Castaic, California, during the winter of 1972-73. The stations were located in sedimentary basins. Beneath the network, the sedimentary rocks of the basins are known to range from 1 to more than 4 km in thickness. Relative time-terms are estimated from P-waves assumed to be propagated by a refractor in the mid-crust, and again from P-waves propagated by a refractor in the upper basement. For the range of velocities reported by others, the two sets of time-terms are very similar. They suggest that both refractors dip to the southwest, and the geology also indicates that the basement dips in this direction. In addition, the P-wave velocity estimated for the refractor of mid-crustal depths, roughly 6.7 km/sec, agrees with values reported by others. Thus, even in this region of complicated geologic structure, the method appears to give realistic results. ?? 1980 Birkha??user Verlag.

  17. Arrival Times of Interplanetary CMEs and Shocks into the Earth's Vicinity: STEREO Observations and Analytical Modeling

    NASA Astrophysics Data System (ADS)

    Ontiveros, V.; Patsourakos, S.; Corona-Romero, P.; Gonzalez-Esparza, J. A.

    2012-01-01

    Interplanetary Coronal Mass Ejections (ICMEs) are one of the largest disturbances in the solar system. ICMEs and their associated shocks are the main cause of intense geomagnetic perturbations, that might affect satellite orbits and telecommunications among other systems. These important repercussions in the Space Weather have lead to a continuous effort to predict the arrival times of the ICMEs and their shocks into the Earth's vicinity, but still the current accuracy in their arrival time to Earth of few hours needs further ramification, in particular for operational purposes. White light images from the STEREO coronagraphs and heliospheric imagers provide an early detection of coronal mass ejections (CMEs) and ICMEs. In February 6, 2011, spacecrafts A and B were 180 degrees apart, each one looking down on a different hemisphere of the Sun and therefore they view from the side Earth-directed events, allowing a better determination of the physical parameters of the events and their kinematics in particular. We take advantage of this configuration and determine the kinematics of the CMEs and ICMEs of Feb 15th (01:56), March 7th (19:43) and June 21st (16:03 UT), 2011. These events have an interplanetary counterpart with Earth arrivals in Feb 18th (00:40 UT), March 10th (05:45 UT) and Jun 23rd (02:18 UT) respectively, as observed by the ACE spacecraft. We perform 3D fittings of the CME-ICME-shock systems viewed by COR1, COR2 HI1 and HI2 to deduce their kinematics and we use our measurements to constrain an analytical model of ICME and shock propagation from the Sun to Earth and compare with the in-situ arrival times to Earth's orbit. This model is applied where the dynamic pressure parameter dominates the solar wind dynamics and it is focused on the role of the transmission of momentum in the ICME-shock system.

  18. Optimal first arrival times in L\\'evy random walk with resetting

    E-print Network

    Kusmierz, Lukasz

    2015-01-01

    We consider diffusive motion of a particle performing a random walk with L\\'evy distributed jump lengths and subject to resetting mechanism bringing the walker to an initial position at uniformly distributed times. In the limit of infinite number of steps and for long times, the process converges to a super-diffusive motion with replenishment. We derive formula for a mean first arrival time (MFAT) to a predefined target position reached by a meandering particle and analyze efficiency of the proposed searching strategy by investigating criteria for an optimal (a shortest possible) MFAT.

  19. Time-dependent solution for the manufacturing line with unreliable machine and batched arrivals

    NASA Astrophysics Data System (ADS)

    Kempa, W. M.; Paprocka, I.; Grabowik, C.; Kalinowski, K.

    2015-11-01

    Time-dependent queue-size distribution in a finite-buffer manufacturing line with unreliable machine is investigated. Successive jobs arrive in batches (groups) with sizes being generally distributed random variables, and are being processed individually with exponential service times. Applying the approach based on the memory less property of exponential distribution and the total probability law, a system of integral equations for the transient queue- size distribution conditioned by the initial level of buffer saturation is derived. The solution of the corresponding system written for Laplace transforms is found via linear-algebraic approach.

  20. Preliminary result of P-wave speed tomography beneath North Sumatera region

    SciTech Connect

    Jatnika, Jajat; Nugraha, Andri Dian; Wandono

    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.

  1. Fast-Time Evaluations of Airborne Merging and Spacing in Terminal Arrival Operations

    NASA Technical Reports Server (NTRS)

    Krishnamurthy, Karthik; Barmore, Bryan; Bussink, Frank; Weitz, Lesley; Dahlene, Laura

    2005-01-01

    NASA researchers are developing new airborne technologies and procedures to increase runway throughput at capacity-constrained airports by improving the precision of inter-arrival spacing at the runway threshold. In this new operational concept, pilots of equipped aircraft are cleared to adjust aircraft speed to achieve a designated spacing interval at the runway threshold, relative to a designated lead aircraft. A new airborne toolset, prototypes of which are being developed at the NASA Langley Research Center, assists pilots in achieving this objective. The current prototype allows precision spacing operations to commence even when the aircraft and its lead are not yet in-trail, but are on merging arrival routes to the runway. A series of fast-time evaluations of the new toolset were conducted at the Langley Research Center during the summer of 2004. The study assessed toolset performance in a mixed fleet of aircraft on three merging arrival streams under a range of operating conditions. The results of the study indicate that the prototype possesses a high degree of robustness to moderate variations in operating conditions.

  2. The function of bilateral odor arrival time differences in olfactory orientation of sharks.

    PubMed

    Gardiner, Jayne M; Atema, Jelle

    2010-07-13

    The direction of an odor signal source can be estimated from bilateral differences in signal intensity and/or arrival time. The best-known examples of the use of arrival time differences are in acoustic orientation. For chemoreception, animals are believed to orient by comparing bilateral odor concentration differences, turning toward higher concentrations. However, time differences should not be ignored, because odor plumes show chaotic intermittency, with the concentration variance several orders of magnitude greater than the concentration mean. We presented a small shark species, Mustelus canis, with carefully timed and measured odor pulses directly into their nares. They turned toward the side stimulated first, even with delayed pulses of higher concentration. This is the first conclusive evidence that under seminatural conditions and without training, bilateral time differences trump odor concentration differences. This response would steer the shark into an odor patch each time and thereby enhance its contact with the plume, i.e., a stream of patches. Animals with more widely spaced nares would be able to resolve smaller angles of attack at higher swimming speeds, a feature that may have contributed to the evolution of hammerhead sharks. This constitutes a novel steering algorithm for tracking odor plumes. PMID:20541411

  3. Analytical arrival and persistence time distributions for flow thresholds in seasonally dry climates

    NASA Astrophysics Data System (ADS)

    Dralle, D.; Thompson, S. E.

    2014-12-01

    Seasonally dry ecosystems, which include Mediterranean, tropical monsoonal and tropical savannah climates, cover approximately 30% of the planet's land area and are globally significant biodiversity hotspots. Due to a highly variable climate, the streamflow available for ecosystems and ecosystems services in these regions is typified by large inter-annual variability. Methods to quantify this variability could shed light on stream ecosystem stress, particularly new stresses imposed by human activity or climate change. This study develops a probabilistic framework to examine controls on dry season flow characteristics in seasonally dry climates. Assuming a typical recession pattern, which is conditioned on an initial value that is sampled from the wet season flows [1,2], analytical PDFs for the arrival time of a given dry season flow threshold can be obtained. Below-flow-threshold persistence time distributions are computed as the difference between an (assumed) normally distributed dry season length and the mean flow threshold arrival time. A number of hypotheses are proposed to explain unexpected sources of variability in the empirical arrival time distributions. The ecologic implications of extended low flow persistence, such as the hydrologic fragmentation of lower order watersheds, are discussed. [1] Müller, M. F., D. N. Dralle, and S. E. Thompson (2014), Analytical model for flow duration curves in seasonally dry climates, Water Resour. Res., 50, doi:10.1002/2014WR015301 [2] Botter, G., A. Porporato, I. Rodriguez-Iturbe, and A. Rinaldo (2007), Basin-scale soil moisture dynamics and the probabilistic characterization of carrier hydrologic flows: Slow, leaching-prone components of the hydrologic response, Water Resour. Res., 43, W02417, doi:10.1029/2006WR005043

  4. Phase sensitive monitoring of electron bunch form and arrival time in superconducting linear accelerators

    SciTech Connect

    Kaya, C.; Schneider, C.; Seidel, W.; Kuntzsch, M.; Bhattacharyya, J.; Mittendorff, M.; Winnerl, S.; Staats, G.; Helm, M.; Michel, P.; Gensch, M.; Al-Shemmary, A.; Stojanovic, N.; Evtushenko, P.

    2012-04-02

    In this Letter, we present a simple approach for monitoring electron bunch form and arrival time combining electro-optic sampling and phase and frequency sensitive signal detection. The sensitivity of the technique has the potential to allow online diagnostics to be performed down to bunch charges in the femto coulomb regime. The concept has high impact for the developments of the next generation of 4th generation x-ray light sources working with long pulse trains or continuous wave mode of operation.

  5. Time-of-arrival analysis applied to ELF/VLF wave generation experiments at HAARP

    NASA Astrophysics Data System (ADS)

    Moore, R. C.; Fujimaru, S.

    2012-12-01

    Time-of-arrival (TOA) analysis is applied to observations performed during ELF/VLF wave generation experiments at the High-frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska. In 2012, a variety of ELF/VLF wave generation techniques were employed to identify the dominant source altitude for each case. Observations were performed for beat-wave modulation, AM modulation, STF modulation, ICD modulation, and cubic frequency modulation, among others. For each of these cases, we identify the dominant ELF/VLF source altitude and compare the experimental results with theoretical HF heating predictions.

  6. VLF long-range lightning location using the arrival time difference technique (ATD)

    NASA Technical Reports Server (NTRS)

    Ierkic, H. Mario

    1996-01-01

    A new network of VLF receiving systems is currently being developed in the USA to support NASA's Tropical Rain Measuring Mission (TRMM). The new network will be deployed in the east coast of the US, including Puerto Rico, and will be operational in late 1995. The system should give affordable, near real-time, accurate lightning locating capabilities at long ranges and with extended coverage. It is based on the Arrival Time Difference (ATD) method of Lee (1986; 1990). The ATD technique is based on the estimation of the time of arrival of sferics detected over an 18 kHz bandwith. The ground system results will be compared and complemented with satellite optical measurements gathered with the already operational Optical Transient Detector (OTD) instrument and in due course with its successor the Lightning Imaging Sensor (LIS). Lightning observations are important to understand atmospheric electrification phenomena, discharge processes, associated phenomena on earth (e.g. whistlers, explosive Spread-F) and other planets. In addition, lightning is a conspicuous indicator of atmospheric activity whose potential is just beginning to be recognized and utilized. On more prosaic grounds, lightning observations are important for protection of life, property and services.

  7. Determination of differential arrival times by cross-correlating worldwide seismological data

    NASA Astrophysics Data System (ADS)

    Godano, M.; Nolet, G.; Zaroli, C.

    2012-12-01

    Cross-correlation delays are the preferred body wave observables in global tomography. Heterogeneity is the main factor influencing delay times found by cross-correlation. Not only the waveform, but also the arrival time itself is affected by differences in seismic velocity encountered along the way. An accurate method for estimating differential times of seismic arrivals across a regional array by cross-correlation was developed by VanDecar and Crosson [1990]. For the estimation of global travel time delays in different frequency bands, Sigloch and Nolet [2006] developed a method for the estimation of body wave delays using a matched filter, which requires the separate estimation of the source time function. Sigloch et al. [2008] found that waveforms often cluster in and opposite the direction of rupture propagation on the fault, confirming that the directivity effect is a major factor in shaping the waveform of large events. We propose a generalization of the VanDecar-Crosson method to which we add a correction for the directivity effect in the seismological data. The new method allows large events to be treated without the need to estimate the source time function for the computation of a matched synthetic waveform. The procedure consists in (1) the detection of the directivity effect in the data and the determination of a rupture model (unilateral or bilateral) explaining the differences in pulse duration among the stations, (2) the determination of an apparent fault rupture length explaining the pulse durations, (3) the removal of the delay due to the directivity effect in the pulse duration , by stretching or contracting the seismograms for directive and anti-directive stations respectively and (4) the application of a generalized VanDecar and Crosson method using only delays between pairs of stations that have an acceptable correlation coefficient. We validate our method by performing tests on synthetic data. Results show that the error between theoretical and measured differential arrival time are significantly reduced for the corrected data. We illustrate our method on data from several real earthquakes.

  8. Comparative Study of Bunch Length And Arrival Time Measurements at FLASH

    SciTech Connect

    Schlarb, H.; Azima, A.; Dusterer, S.; Huning, M.; Knabbe, E.A.; Roehrs, M.; Rybnikov, V.; Schmidt, B.; Steffen, B.; Ross, M.C.; Schmueser, P.; Winter, A.; /Hamburg U.

    2007-04-16

    Diagnostic devices to precisely measure the longitudinal electron beam profile and the bunch arrival time require elaborate new instrumentation techniques. At FLASH, two entirely different methods are used. The bunch profile can be determined with high precision by a transverse deflecting RF structure, but the method is disruptive and does not allow to monitor multiple bunches in a macro-pulse train. It is therefore complemented by two non-disruptive electrooptical devices, called EO and TEO. The EO setup uses a dedicated diagnostic laser synchronized to the machine RF. The longitudinal electron beam profile is encoded in the intensity profile of a chirped laser pulse and analyzed by looking at the spectral composition of the pulse. The second setup, TEO, utilizes the TiSa-based laser system used for pump-probe experiments. Here, the temporal electron shape is encoded into the spatial dimension of the laser pulse by an intersection angle between the laser and the electron beam at the EO-crystal. In this paper, we present a comparative study of bunch length and arrival time measurements performed simultaneously with all three experimental techniques.

  9. Periodic modulation in pulse arrival times from young pulsars: a renewed case for neutron star precession

    NASA Astrophysics Data System (ADS)

    Kerr, M.; Hobbs, G.; Johnston, S.; Shannon, R. M.

    2016-01-01

    In a search for periodic variation in the arrival times of pulses from 151 young, energetic pulsars, we have identified seven cases of modulation consistent with one or two harmonics of a single fundamental with time-scale 0.5-1.5 yr. We use simulations to show that these modulations are statistically significant and of high quality (sinusoidal) even when contaminated by the strong stochastic timing noise common to young pulsars. Although planetary companions could induce such modulation, the large implied masses and 2:1 mean motion resonances challenge such an explanation. Instead, the modulation is likely to be intrinsic to the pulsar, arising from quasi-periodic switching between stable magnetospheric states, and we propose that precession of the neutron star may regulate this switching.

  10. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...departure/arrival dates and times on my travel claim? 301-11.10...departure/arrival dates and times on my travel claim? You must record...record departure/arrival times, but you must annotate your travel claim when your travel...

  11. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...departure/arrival dates and times on my travel claim? 301-11.10...departure/arrival dates and times on my travel claim? You must record...record departure/arrival times, but you must annotate your travel claim when your travel...

  12. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...departure/arrival dates and times on my travel claim? 301-11.10...departure/arrival dates and times on my travel claim? You must record...record departure/arrival times, but you must annotate your travel claim when your travel...

  13. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...departure/arrival dates and times on my travel claim? 301-11.10...departure/arrival dates and times on my travel claim? You must record...record departure/arrival times, but you must annotate your travel claim when your travel...

  14. Timing of initial arrival at the breeding site predicts age at first reproduction in a long-lived migratory bird.

    PubMed

    Becker, Peter H; Dittmann, Tobias; Ludwigs, Jan-Dieter; Limmer, Bente; Ludwig, Sonja C; Bauch, Christina; Braasch, Alexander; Wendeln, Helmut

    2008-08-26

    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

  15. Joint Inversion of Body-Wave Arrival Times and Surface-Wave Dispersion for Three-Dimensional Seismic Structure Around SAFOD

    NASA Astrophysics Data System (ADS)

    Zhang, Haijiang; Maceira, Monica; Roux, Philippe; Thurber, Clifford

    2014-11-01

    We incorporate body-wave arrival time and surface-wave dispersion data into a joint inversion for three-dimensional P-wave and S-wave velocity structure of the crust surrounding the site of the San Andreas Fault Observatory at Depth. The contributions of the two data types to the inversion are controlled by the relative weighting of the respective equations. We find that the trade-off between fitting the two data types, controlled by the weighting, defines a clear optimal solution. Varying the weighting away from the optimal point leads to sharp increases in misfit for one data type with only modest reduction in misfit for the other data type. All the acceptable solutions yield structures with similar primary features, but the smaller-scale features change substantially. When there is a lower relative weight on the surface-wave data, it appears that the solution over-fits the body-wave data, leading to a relatively rough V s model, whereas for the optimal weighting, we obtain a relatively smooth model that is able to fit both the body-wave and surface-wave observations adequately.

  16. Seismicity and arrival-time residuals from the Victoria Earthquake of June 9, 1980

    SciTech Connect

    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.

  17. Relaxing the closure assumption in single-season occupancy models: staggered arrival and departure times

    USGS Publications Warehouse

    Kendall, William L.; Hines, James E.; Nichols, James D.; Grant, Evan H. Campbell

    2013-01-01

    Occupancy statistical models that account for imperfect detection have proved very useful in several areas of ecology, including species distribution and spatial dynamics, disease ecology, and ecological responses to climate change. These models are based on the collection of multiple samples at each of a number of sites within a given season, during which it is assumed the species is either absent or present and available for detection while each sample is taken. However, for some species, individuals are only present or available for detection seasonally. We present a statistical model that relaxes the closure assumption within a season by permitting staggered entry and exit times for the species of interest at each site. Based on simulation, our open model eliminates bias in occupancy estimators and in some cases increases precision. The power to detect the violation of closure is high if detection probability is reasonably high. In addition to providing more robust estimation of occupancy, this model permits comparison of phenology across sites, species, or years, by modeling variation in arrival or departure probabilities. In a comparison of four species of amphibians in Maryland we found that two toad species arrived at breeding sites later in the season than a salamander and frog species, and departed from sites earlier.

  18. Relaxing the closure assumption in occupancy models: staggered arrival and departure times.

    PubMed

    Kendall, William L; Hines, James E; Nichols, James D; Grant, Evan H Campbell

    2013-03-01

    Occupancy statistical models that account for imperfect detection have proved very useful in several areas of ecology, including species distribution and spatial dynamics, disease ecology, and ecological responses to climate change. These models are based on the collection of multiple samples at each of a number of sites within a given season, during which it is assumed the species is either absent or present and available for detection while each sample is taken. However, for some species, individuals are only present or available for detection seasonally. We present a statistical model that relaxes the closure assumption within a season by permitting staggered entry and exit times for the species of interest at each site. Based on simulation, our open model eliminates bias in occupancy estimators and in some cases increases precision. The power to detect the violation of closure is high if detection probability is reasonably high. In addition to providing more robust estimation of occupancy, this model permits comparison of phenology across sites, species, or years, by modeling variation in arrival or departure probabilities. In a comparison of four species of amphibians in Maryland we found that two toad species arrived at breeding sites later in the season than a salamander and frog species, and departed from sites earlier. PMID:23687887

  19. Airborne Evaluation and Demonstration of a Time-Based Airborne Inter-Arrival Spacing Tool

    NASA Technical Reports Server (NTRS)

    Lohr, Gary W.; Oseguera-Lohr, Rosa M.; Abbott, Terence S.; Capron, William R.; Howell, Charles T.

    2005-01-01

    An airborne tool has been developed that allows an aircraft to obtain a precise inter-arrival time-based spacing interval from the preceding aircraft. The Advanced Terminal Area Approach Spacing (ATAAS) tool uses Automatic Dependent Surveillance-Broadcast (ADS-B) data to compute speed commands for the ATAAS-equipped aircraft to obtain this inter-arrival spacing behind another aircraft. The tool was evaluated in an operational environment at the Chicago O'Hare International Airport and in the surrounding terminal area with three participating aircraft flying fixed route area navigation (RNAV) paths and vector scenarios. Both manual and autothrottle speed management were included in the scenarios to demonstrate the ability to use ATAAS with either method of speed management. The results on the overall delivery precision of the tool, based on a target spacing of 90 seconds, were a mean of 90.8 seconds with a standard deviation of 7.7 seconds. The results for the RNAV and vector cases were, respectively, M=89.3, SD=4.9 and M=91.7, SD=9.0.

  20. Spectral encoding method for measuring the relative arrival time between x-ray/optical pulses

    NASA Astrophysics Data System (ADS)

    Bionta, M. R.; Hartmann, N.; Weaver, M.; French, D.; Nicholson, D. J.; Cryan, J. P.; Glownia, J. M.; Baker, K.; Bostedt, C.; Chollet, M.; Ding, Y.; Fritz, D. M.; Fry, A. R.; Kane, D. J.; Krzywinski, J.; Lemke, H. T.; Messerschmidt, M.; Schorb, S.; Zhu, D.; White, W. E.; Coffee, R. N.

    2014-08-01

    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.

  1. Spectral encoding method for measuring the relative arrival time between x-ray/optical pulses

    SciTech Connect

    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.; and others

    2014-08-15

    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.

  2. Sex differences in accuracy and precision when judging time to arrival: data from two Internet studies.

    PubMed

    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. PMID:21125324

  3. Constrained Optimization of Average Arrival Time via a Probabilistic Approach to Transport Reliability

    PubMed Central

    Namazi-Rad, Mohammad-Reza; Dunbar, Michelle; Ghaderi, Hadi; Mokhtarian, Payam

    2015-01-01

    To achieve greater transit-time reduction and improvement in reliability of transport services, there is an increasing need to assist transport planners in understanding the value of punctuality; i.e. the potential improvements, not only to service quality and the consumer but also to the actual profitability of the service. In order for this to be achieved, it is important to understand the network-specific aspects that affect both the ability to decrease transit-time, and the associated cost-benefit of doing so. In this paper, we outline a framework for evaluating the effectiveness of proposed changes to average transit-time, so as to determine the optimal choice of average arrival time subject to desired punctuality levels whilst simultaneously minimizing operational costs. We model the service transit-time variability using a truncated probability density function, and simultaneously compare the trade-off between potential gains and increased service costs, for several commonly employed cost-benefit functions of general form. We formulate this problem as a constrained optimization problem to determine the optimal choice of average transit time, so as to increase the level of service punctuality, whilst simultaneously ensuring a minimum level of cost-benefit to the service operator. PMID:25992902

  4. Analysis of small intestinal transit and colon arrival times of non-disintegrating tablets administered in the fasted state.

    PubMed

    Pišlar, Mitja; Brelih, Hana; Mrhar, Aleš; Bogataj, Marija

    2015-07-30

    In this study individual data on tablet gastrointestinal transit times (i.e. gastric emptying, small intestinal transit, ileocecal junction residence, and colon arrival times) were obtained from literature in order to present and analyze their distributions and relationships. The influence of the time of food intake after tablet administration in fasted state on gastrointestinal transit times was additionally evaluated. There were 114 measurements from subjects who received the first meal at 4h after tablet administration. Approximately 32% of the tablets arrived into the colon before the meal intake at 4h. An evident increase in the frequency of colon arrival of tablets within 40min after the meal intake at 4h post-dose was observed, where approximately 39% of all tablets arrived into the colon. This is in accordance with findings described in literature where a meal ingested several hours post-dose accelerates tablet transit through the terminal ileum and shortens the transit through the small intestine. The median (min, max) of gastric emptying, small intestinal transit, and colon arrival times in the group where the first meal intake was at 4h post-dose is 35 (0,192), 215 (60,544), and 254 (117,604) minutes, respectively. The dependence of colon arrival times on gastric emptying times was described by the nonparametric regression curve, and compared with the presumed interval of colon arrival times, calculated by summation of observed gastric emptying times and frequently cited small intestinal transit time interval, i.e. 3-4h. For shorter gastric emptying times the trend of colon arrival times was within the presumed interval. At short gastric emptying times many observation points are also within the presumed interval since this interval coincides with short period after meal intake at 4h post-dose. Additionally, in numerous occasions relatively long ileocecal junction residence times were obtained, which may be important information from the point of view of drug absorption. The findings of gastrointestinal transit times are important and should be taken into consideration when predicting the in vivo performance of dosage forms after oral administration. PMID:25769525

  5. A Bayesian parameter estimation approach to pulsar time-of-arrival analysis

    E-print Network

    C. Messenger; A. Lommen; P. Demorest; S. Ransom

    2011-03-02

    The increasing sensitivities of pulsar timing arrays to ultra-low frequency (nHz) gravitational waves promises to achieve direct gravitational wave detection within the next 5-10 years. While there are many parallel efforts being made in the improvement of telescope sensitivity, the detection of stable millisecond pulsars and the improvement of the timing software, there are reasons to believe that the methods used to accurately determine the time-of-arrival (TOA) of pulses from radio pulsars can be improved upon. More specifically, the determination of the uncertainties on these TOAs, which strongly affect the ability to detect GWs through pulsar timing, may be unreliable. We propose two Bayesian methods for the generation of pulsar TOAs starting from pulsar "search-mode" data and pre-folded data. These methods are applied to simulated toy-model examples and in this initial work we focus on the issue of uncertainties in the folding period. The final results of our analysis are expressed in the form of posterior probability distributions on the signal parameters (including the TOA) from a single observation.

  6. Priority Effects of Time of Arrival of Plant Functional Groups Override Sowing Interval or Density Effects: A Grassland Experiment

    PubMed Central

    von Gillhaussen, Philipp; Rascher, Uwe; Jablonowski, Nicolai D.; Plückers, Christine; Beierkuhnlein, Carl; Temperton, Vicky M.

    2014-01-01

    Priority effects occur when species that arrive first in a habitat significantly affect the establishment, growth, or reproduction of species arriving later and thus affect functioning of communities. However, we know little about how the timing of arrival of functionally different species may alter structure and function during assembly. Even less is known about how plant density might interact with initial assembly. In a greenhouse experiment legumes, grasses or forbs were sown a number of weeks before the other two plant functional types were sown (PFT) in combination with a sowing density treatment. Legumes, grasses or non-legume forbs were sown first at three different density levels followed by sowing of the remaining PFTs after three or six-weeks. We found that the order of arrival of different plant functional types had a much stronger influence on aboveground productivity than sowing density or interval between the sowing events. The sowing of legumes before the other PFTs produced the highest aboveground biomass. The larger sowing interval led to higher asymmetric competition, with highest dominance of the PFT sown first. It seems that legumes were better able to get a head-start and be productive before the later groups arrived, but that their traits allowed for better subsequent establishment of non-legume PFTs. Our study indicates that the manipulation of the order of arrival can create priority effects which favour functional groups of plants differently and thus induce different assembly routes and affect community composition and functioning. PMID:24497995

  7. Characterizing the nonlinear interaction of S- and P-waves in a rock sample

    NASA Astrophysics Data System (ADS)

    Gallot, Thomas; Malcolm, Alison; Szabo, Thomas L.; Brown, Stephen; Burns, Daniel; Fehler, Michael

    2015-01-01

    The nonlinear elastic response of rocks is known to be caused by the rocks' microstructure, particularly cracks and fluids. This paper presents a method for characterizing the nonlinearity of rocks in a laboratory scale experiment with a unique configuration. This configuration has been designed to open up the possibility of using the nonlinear characterization of rocks as an imaging tool in the field. In our experiment, we study the nonlinear interaction of two traveling waves: a low-amplitude 500 kHz P-wave probe and a high-amplitude 50 kHz S-wave pump in a room-dry 15 × 15 × 3 cm slab of Berea sandstone. Changes in the arrival time of the P-wave probe as it passes through the perturbation created by the traveling S-wave pump were recorded. Waveforms were time gated to simulate a semi-infinite medium. The shear wave phase relative to the P-wave probe signal was varied with resultant changes in the P-wave probe arrival time of up to 100 ns, corresponding to a change in elastic properties of 0.2%. In order to estimate the strain in our sample, we also measured the particle velocity at the sample surface to scale a finite difference linear elastic simulation to estimate the complex strain field in the sample, on the order of 10-6, induced by the S-wave pump. We derived a fourth order elastic model to relate the changes in elasticity to the pump strain components. We recover quadratic and cubic nonlinear parameters: ? ˜ = - 872 and ? ˜ = - 1.1 × 10 10 , respectively, at room-temperature and when particle motions of the pump and probe waves are aligned. Temperature fluctuations are correlated to changes in the recovered values of ? ˜ and ? ˜ , and we find that the nonlinear parameter changes when the particle motions are orthogonal. No evidence of slow dynamics was seen in our measurements. The same experimental configuration, when applied to Lucite and aluminum, produced no measurable nonlinear effects. In summary, a method of selectively determining the local nonlinear characteristics of rock quantitatively has been demonstrated using traveling sound waves.

  8. Ultra-Wideband Time-Difference-of-Arrival High Resolution 3D Proximity Tracking System

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Phan, Chau; Dekome, Kent; Dusl, John

    2010-01-01

    This paper describes a research and development effort for a prototype ultra-wideband (UWB) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being studied for use in tracking of lunar./Mars rovers and astronauts during early exploration missions when satellite navigation systems are not available. U IATB impulse radio (UWB-IR) technology is exploited in the design and implementation of the prototype location and tracking system. A three-dimensional (3D) proximity tracking prototype design using commercially available UWB products is proposed to implement the Time-Difference- Of-Arrival (TDOA) tracking methodology in this research effort. The TDOA tracking algorithm is utilized for location estimation in the prototype system, not only to exploit the precise time resolution possible with UWB signals, but also to eliminate the need for synchronization between the transmitter and the receiver. Simulations show that the TDOA algorithm can achieve the fine tracking resolution with low noise TDOA estimates for close-in tracking. Field tests demonstrated that this prototype UWB TDOA High Resolution 3D Proximity Tracking System is feasible for providing positioning-awareness information in a 3D space to a robotic control system. This 3D tracking system is developed for a robotic control system in a facility called "Moonyard" at Honeywell Defense & System in Arizona under a Space Act Agreement.

  9. Estimating permeability from quasi-static deformation: Temporal variations and arrival time inversion

    SciTech Connect

    Vasco, D.W.; Ferretti, Alessandro; Novali, Fabrizio

    2008-05-01

    Transient pressure variations within a reservoir can be treated as a propagating front and analyzed using an asymptotic formulation. From this perspective one can define a pressure 'arrival time' and formulate solutions along trajectories, in the manner of ray theory. We combine this methodology and a technique for mapping overburden deformation into reservoir volume change as a means to estimate reservoir flow properties, such as permeability. Given the entire 'travel time' or phase field, obtained from the deformation data, we can construct the trajectories directly, there-by linearizing the inverse problem. A numerical study indicates that, using this approach, we can infer large-scale variations in flow properties. In an application to Interferometric Synthetic Aperture (InSAR) observations associated with a CO{sub 2} injection at the Krechba field, Algeria, we image pressure propagation to the northwest. An inversion for flow properties indicates a linear trend of high permeability. The high permeability correlates with a northwest trending fault on the flank of the anticline which defines the field.

  10. Evaluation of Operational Procedures for Using a Time-Based Airborne Inter-arrival Spacing Tool

    NASA Technical Reports Server (NTRS)

    Oseguera-Lohr, Rosa M.; Lohr, Gary W.; Abbott, Terence S.; Eischeid, Todd M.

    2002-01-01

    An airborne tool has been developed based on the concept of an aircraft maintaining a time-based spacing interval from the preceding aircraft. The Advanced Terminal Area Approach Spacing (ATAAS) tool uses Automatic Dependent Surveillance-Broadcast (ADS-B) aircraft state data to compute a speed command for the ATAAS-equipped aircraft to obtain a required time interval behind another aircraft. The tool and candidate operational procedures were tested in a high-fidelity, full mission simulator with active airline subject pilots flying an arrival scenario using three different modes for speed control. The objectives of this study were to validate the results of a prior Monte Carlo analysis of the ATAAS algorithm and to evaluate the concept from the standpoint of pilot acceptability and workload. Results showed that the aircraft was able to consistently achieve the target spacing interval within one second (the equivalent of approximately 220 ft at a final approach speed of 130 kt) when the ATAAS speed guidance was autothrottle-coupled, and a slightly greater (4-5 seconds), but consistent interval with the pilot-controlled speed modes. The subject pilots generally rated the workload level with the ATAAS procedure as similar to that with standard procedures, and also rated most aspects of the procedure high in terms of acceptability. Although pilots indicated that the head-down time was higher with ATAAS, the acceptability of head-down time was rated high. Oculometer data indicated slight changes in instrument scan patterns, but no significant change in the amount of time spent looking out the window between the ATAAS procedure versus standard procedures.

  11. Using all seismic arrivals in shallow seismic investigations

    NASA Astrophysics Data System (ADS)

    Fabien-Ouellet, Gabriel; Fortier, Richard

    2014-04-01

    Near surface seismic investigations are expensive and time-consuming. Moreover, seismic processing usually focuses on one particular type of wave and wastes much of the information contained in seismic records that could be used to make near surface seismic surveys more valuable and cost effective. A workflow is proposed herein that combines seismic refraction tomography, multichannel analysis of surface waves (MASW), and seismic reflection using P-waves and SV-waves, which takes advantage of P-wave first arrivals, Rayleigh waves, and P-wave and SV-wave reflections, respectively. The use of the proposed methodology is shown through three case studies carried out in the Outaouais region, Quebec, Canada, using a 24-channel seismograph, vertical geophones, and a sledgehammer. The results show that it is possible to acquire SV-reflections at sites where a strong velocity reversal is present at the surface using only vertical geophones. Under that condition, or more generally when two component geophones are used, the proposed workflow leads to two complementary stacked sections: 1) an SV-wave section that has a high resolution even at shallow depths but can lack coherency and 2) a P-wave section that has better coherency but is blind at shallow depths. Two velocity models are also produced: an SV-wave model that combines the results from MASW and SV-wave reflections and a P-wave model that combines the results from seismic refraction and P-wave reflections. The workflow uses the frequency variant linear move-out (FV-LMO) surface wave filter, which is much more efficient than band pass or f-k filters to process SV waves. The value of many near surface seismic surveys can thus be enhanced by processing all propagation modes, especially when SV-wave reflections are present due to their high resolution.

  12. Arrival time of solar eruptive CMEs associated with ICMEs of magnetic cloud and ejecta

    NASA Astrophysics Data System (ADS)

    Shanmugaraju, A.; Syed Ibrahim, M.; Moon, Y.-J.; Kasro Lourdhina, K.; Dharanya, M.

    2015-05-01

    The Coronal Mass Ejection (CME) is an eruptive event in which magnetic plasma is ejected from the Sun into space through the solar corona. We considered a set of 51 Interplanetary Coronal Mass Ejections (ICMEs) listed by Kim et al. (Solar Phys. 184:77, 2013) from Coordinated Data Analysis Workshop (CDAW, Gopalswamy et al. in Astrophys. J. 710:1111, 2010). Among the 51 events, 22 events are classified as Magnetic Clouds (MC) and 29 events are classified as Ejecta (EJ) where the MC and EJ are subsets of ICMEs. We have analyzed the physical properties of CMEs and ICMEs associated with MC and EJ, and correlated them with the CME's transit time/arrival time from the Sun to the Earth. Main aims of the present study are to examine (a) dependence of transit time on the properties of CMEs and ICMEs, and (b) differences between MC and EJ. It is found that CME's initial speed decides the transit time which is in support of the known results in literature. Apart from this, some important results from the present study are: (i) transit time predicted using an empirical relation obtained in the present work is found comparable with the observations (correlation coefficient=0.70). (ii) The transit time of MC and EJ-associated CMEs ranges from 20 to 120 hours and IP acceleration lies between -10 m/s2 to 5 m/s2. (iii) There are certain differences between MC and EJ such as: (a) Ejecta takes slightly more time to travel and only 30 % of them are accelerated in the interplanetary medium. Whereas, MC takes less time to travel and nearly 50 % of them are accelerated, (b) The correlations of IP acceleration and speed with transit time are higher for MC than that of EJ, (c) A weak relationship between the deflection and transit time is found for MC, but it is absent in the case of EJ and (d) Only EJ-type CMEs have wider range of direction parameter and acceleration. Further, we checked the solar wind speed as another parameter has any influence on CME acceleration and it shows that there is no clear dependence between the two parameters. While it is observed that the average acceleration of MC-associated CME is larger for lower direction parameter values (<0.2), it is larger for EJ-associated CME for higher direction parameter values (>0.6).

  13. Fault zone structure determined through the analysis of earthquake arrival times

    SciTech Connect

    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.

  14. Combining Analyst and Waveform-Correlation-Based Arrival Time Measurements in the Bayesloc Multiple-Event Location Algorithm

    NASA Astrophysics Data System (ADS)

    Myers, S. C.; Johannesson, G.; Dodge, D. A.; Simmons, N. A.

    2011-12-01

    We implement an efficient waveform-correlation method to determine relative arrival times and we add relative arrival-time measurements to the Bayesloc multiple-event location algorithm. Because the arrival time of seismic phases is a powerful indicator of phase type, we use Bayesloc to probabilistically determine the phase labels for the correlation picks during simultaneous multiple-event location. Bayesloc is a formulation of joint probability over event locations, travel time corrections, phase labels, and arrival-time measurement errors. The Bayesloc formulation is hierarchical with distinct statistical models for each component of the multiple-event system, including prior constraints for any of the parameters. Bayes' Theorem allows calculation of the joint probability for hypothesized configurations of Bayesloc parameters, which facilitates using the Markov-Chain Monte Carlo (MCMC) method to draw samples from the joint probability function. The marginal posteriori distribution for each parameter or covariance between parameters is inferred from MCMC samples. Correlation-based picks are integrated into the Bayesloc formulation by including a new category of arrival time measurement that is derived from correlation of empirical waveforms. Because relative picks are derived from correlation between two waveforms and absolute-time picks are made by analysis of a single waveform - typically an analyst - error processes for relative and absolute arrival time measurements are modeled independently. Relative pick precision is formulated as a function of correlation coefficient and the time-bandwidth product of the correlated waveforms, and absolute arrival times precision - as described in previous work - is formulated as a function phase type, the station, and the individual event. We adopt widely used methodologies for computing differential times based on waveform cross correlation. We first collect all waveforms for a given station and event cluster. A user-specified, phase-specific bandpass filter is applied to each waveform and the phase window is cut from the seismogram based on either analyst picks or a theoretical arrival time. We then compute and save the Fourier transform of each phase-windowed seismogram. Complex multiplication in the frequency domain is used to compute auto correlation and cross correlation spectra. Cross correlation spectra are inverse transformed and normalized based on the average of the autocorrelation amplitudes to produce a normalized, time-domain correlation function. The correlation coefficient is the peak of the correlation function and the time shift is the offset of the peak from the center of the correlation function. The time shift and the correlation coefficient are refined by fitting a parabolic function to the sample points in the neighborhood of the peak in the time-domain correlation function, which allows sub-sample precision for the correlation pick. The difference in time between the arrivals is computed by differencing the start time of the phase windows and adding the correlation-based time shift. Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-CONF-490688.

  15. The Development of a General Associative Learning Account of Skill Acquisition in a Relative Arrival-Time Judgment Task

    ERIC Educational Resources Information Center

    Loft, Shayne; Neal, Andrew; Humphreys, Michael S.

    2007-01-01

    Current theory assumes that individuals only use information from the immediate environment to perform relative arrival-time judgment tasks. This article presents a theoretical analysis of the memory requirements of this task. The authors present an analysis of the inputs to the memory system and the processes that map those inputs onto outputs.…

  16. The effect of small-scale heterogeneity on the arrival time of waves Jesper Spetzler and Roel Snieder*

    E-print Network

    Snieder, Roel

    with a length scale smaller than the width of Fresnel zones. In the regime for which scattering theory prediction of finite frequency arrival times of waves by scattering theory. The regime of scattering theory is relevant when the characteristic length of heterogeneity is smaller than the width of Fresnel zones

  17. Landscape-scale pest suppression is mediated by timing of predator arrival.

    PubMed

    Costamagna, Alejandro C; Venables, William N; Schellhorn, Nancy A

    2015-06-01

    There is increasing evidence that biological control of agricultural pests is affected by the landscape context, although the mechanisms behind this pattern have received little attention. Ecological theory predicts that one key mechanism mediating successful pest suppression is early predator immigration to agricultural fields. However, the importance of this population process under different landscape contexts remains unknown. Here, we elucidate the relative importance of landscape context and timing of predator immigration on aphid suppression by manipulating exposure to predation in agroecosystems located across a gradient of landscape complexity in a subtropical horticultural region in Australia. Aphid suppression varied with landscape context, from populations escaping control to almost complete pest suppression. In general, we found higher aphid suppression when predators were allowed immediate and continuous access to aphids than when predators were delayed or excluded for a week, but responses varied in each landscape. Contrary to previous reports from temperate agricultural landscapes, aphid suppression was neutral or negatively associated with natural and seminatural vegetation, whereas aphid suppression was positively associated with landscapes with a higher proportion of alfalfa. When landscapes were classified according to their levels of complexity, we showed that early predation resulted in similar levels of pest suppression in simplified landscapes (i.e., with low proportions of alfalfa and habitat diversity) as late predation in complex landscapes (i.e., with high proportions of alfalfa and habitat diversity). Our data show that timing of predator arrival to agricultural fields is as important as landscape complexity for mediating pest control in agroecosystems. Furthermore, our results suggest that key distributions of suitable habitats that facilitate natural enemy movement can enhance biological control in simplified landscapes. PMID:26465046

  18. Design and Performance Evaluation on Ultra-Wideband Time-Of-Arrival 3D Tracking System

    NASA Technical Reports Server (NTRS)

    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".

  19. `Inter-Arrival Time' Inspired Algorithm and its Application in Clustering and Molecular Phylogeny

    NASA Astrophysics Data System (ADS)

    Kolekar, Pandurang S.; Kale, Mohan M.; Kulkarni-Kale, Urmila

    2010-10-01

    Bioinformatics, being multidisciplinary field, involves applications of various methods from allied areas of Science for data mining using computational approaches. Clustering and molecular phylogeny is one of the key areas in Bioinformatics, which help in study of classification and evolution of organisms. Molecular phylogeny algorithms can be divided into distance based and character based methods. But most of these methods are dependent on pre-alignment of sequences and become computationally intensive with increase in size of data and hence demand alternative efficient approaches. `Inter arrival time distribution' (IATD) is a popular concept in the theory of stochastic system modeling but its potential in molecular data analysis has not been fully explored. The present study reports application of IATD in Bioinformatics for clustering and molecular phylogeny. The proposed method provides IATDs of nucleotides in genomic sequences. The distance function based on statistical parameters of IATDs is proposed and distance matrix thus obtained is used for the purpose of clustering and molecular phylogeny. The method is applied on a dataset of 3' non-coding region sequences (NCR) of Dengue virus type 3 (DENV-3), subtype III, reported in 2008. The phylogram thus obtained revealed the geographical distribution of DENV-3 isolates. Sri Lankan DENV-3 isolates were further observed to be clustered in two sub-clades corresponding to pre and post Dengue hemorrhagic fever emergence groups. These results are consistent with those reported earlier, which are obtained using pre-aligned sequence data as an input. These findings encourage applications of the IATD based method in molecular phylogenetic analysis in particular and data mining in general.

  20. Arterial spin labelling reveals prolonged arterial arrival time in idiopathic Parkinson's disease

    PubMed Central

    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. PMID:25379411

  1. The Great "Non-Event" of 7 January 2014: Challenges in CME Arrival Time and Geomagnetic Storm Strength Prediction

    NASA Astrophysics Data System (ADS)

    Mays, M. L.; Thompson, B. J.; Jian, L.; Evans, R. M.; Savani, N.; Odstrcil, D.; Nieves-Chinchilla, T.; Richardson, I. G.

    2014-12-01

    We present a case study of the 7 January 2014 event in order to highlight current challenges in space weather forecasting of CME arrival time and geomagnetic storm strength. On 7 January 2014 an X1.2 flare and CME with a radial speed ~2400 km/s was observed from active region 11943. The flaring region was only ten degrees southwest of disk center with extensive dimming south of the active region and preliminary analysis indicated a fairly rapid arrival at Earth (~36 hours). Of the eleven forecasting groups world-wide who participated in CCMC's Space Weather Scoreboard (http://kauai.ccmc.gsfc.nasa.gov/SWScoreBoard), nine predicted early arrivals and six predicted dramatic geomagnetic storm impacts (Kp predictions ranged from 6 to 9). However, the CME only had a glancing blow arrival at Earth - Kp did not rise above 3 and there was no geomagnetic storm. What happened? One idea is that the large coronal hole to the northeast of the active region could have deflected the CME. This coronal hole produced a high speed stream near Earth reaching an uncommon speed of 900 km/s four days after the observed CME arrival. However, no clear CME deflection was observed in the outer coronagraph fields of view (~5-20Rs) where CME measurements are derived to initiate models, therefore deflection seems unlikely. Another idea is the effect of the CME flux rope orientation with respect to Earth orbit. We show that using elliptical major and minor axis widths obtained by GCS fitting for the initial CME parameters in ENLIL would have improved the forecast to better reflect the observed glancing blow in-situ signature. We also explore the WSA-ENLIL+Cone simulations, the background solar wind solution, and compare with the observed CME arrival at Venus (from Venus Express) and Earth.

  2. Three-dimensional P-wave velocity structure of Mt. Etna, Italy

    USGS Publications Warehouse

    Villasenor, A.; Benz, H.M.; Filippi, L.; De Luca, G.; Scarpa, R.; Patane, G.; Vinciguerra, S.

    1998-01-01

    The three-dimensional P-wave velocity structure of Mt. Etna is determined to depths of 15 km by tomographic inversion of first arrival times from local earthquakes recorded by a network of 29 permanent and temporary seismographs. Results show a near-vertical low-velocity zone that extends from beneath the central craters to a depth of 10 km. This low-velocity region is coincident with a band of steeply-dipping seismicity, suggesting a magmatic conduit that feeds the summit eruptions. The most prominent structure is an approximately 8-km-diameter high-velocity body located between 2 and 12 km depth below the southeast flank of the volcano. This high-velocity body is interpreted as a remnant mafic intrusion that is an important structural feature influencing both volcanism and east flank slope stability and faulting.

  3. YO!-A Time-of-Arrival Receiver for Removal of Femtosecond Helicity-Correlated Beam Effects

    SciTech Connect

    John Musson; Trent Allison; Arne Freyberger; Joachim Kuhn; Brian Quinn

    2004-05-02

    The G0 parity violation experiment at Jefferson Lab is based on time-of-flight measurements, and is sensitive to timing effects between the two electron helicity states of the beam. Photon counters triggered by time-of-arrival at the target mandate that timing must be independent of delays associated with different orbits taken by the two helicity states. In addition, the standard 499 MHz beam structure is altered such that 1 of every 16 microbunches are filled, resulting in an arrival frequency of 31.1875 (31) MHz, and an average current of 40 {micro}A. Helicity correction involves identifying and tracking the 31 MHz subharmonic, applying a fast/fine phase correction, and finally producing a clean 31 MHz trigger and a 499 MHz clock train. These signals are phase-matched to the beam arrival at the target on the order of femtoseconds. The 10 kHz output bandwidth is sufficiently greater than the 30 Hz helicity flip settling time (500 {micro}s). This permits the system to correct each helicity bin for any orbit-induced timing inequalities. A sampling phase detection scheme is used in order to eliminate the unavoidable 2n/n phase shifts associated with frequency dividers. Conventional receiver architecture and DSP techniques are combined for maximum sensitivity, bandwidth, and flexibility. Results of bench tests, commissioning and production data will be presented.

  4. P wave anisotropic tomography of the Nankai subduction zone in Southwest Japan

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Zhao, Dapeng

    2012-05-01

    The active subduction of the young Philippine Sea (PHS) plate and the old Pacific plate has resulted in significant seismic heterogeneity and anisotropy in Southwest (SW) Japan. In this work we determined a detailed 3-D P wave anisotropic tomography of the crust and upper mantle beneath SW Japan using ˜540,000 P wave arrival times from 5,249 local earthquakes recorded by 1095 stations. The PHS slab is imaged clearly as a high-velocity (high-V) anomaly which exhibits considerable lateral variations. Significant low-velocity (low-V) anomalies are revealed above and below the PHS slab. The low-V anomalies above the PHS slab may reflect the upwelling flow in the mantle wedge and the PHS slab dehydration, and they form the source zone of the arc volcanoes in SW Japan. The low-V zones under the PHS slab may reflect the upwelling flow in the big mantle wedge above the Pacific slab. The anisotropy in the crust and upper mantle is complex. In Kyushu, the P wave fast velocity direction (FVD) is generally trench-normal in the mantle wedge under the back-arc, which is consistent with the corner flow driven by the PHS slab subduction. The FVD is trench-parallel in the subducting PHS slab under Kyushu. We think that the intraslab seismicity is a potential indicator to the slab anisotropy. That is, the PHS slab with seismicity has kept its original fossil anisotropy formed at the mid-ocean ridge, while the aseismic PHS slab has reproduced the anisotropy according to its current deformation.

  5. P wave tomography and anisotropy beneath Southeast Asia: Insight into mantle dynamics

    NASA Astrophysics Data System (ADS)

    Huang, Zhouchuan; Zhao, Dapeng; Wang, Liangshu

    2015-07-01

    Southeast Asia is surrounded by subduction zones resulting from the interactions of several lithospheric plates. Its evolution has been also influenced by active tectonics due to the Indo-Asian collision in the Cenozoic. In this study, we use a large number of arrival-time data of local and regional earthquakes to determine 3-D P wave tomography and azimuthal anisotropy in the mantle beneath SE Asia. High-velocity (high-V) anomalies representing the subducting slabs are clearly visible in the upper mantle and the mantle transition zone (MTZ). Low-velocity (low-V) zones with trench-normal anisotropy are revealed in the uppermost mantle, which indicate back-arc spreading or secondary mantle-wedge flow induced by the slab subduction. In contrast, trench-parallel anisotropy dominates in the deep upper mantle and reflects structures either in the subducting slab or in the upper mantle surrounding the slab. The trench-parallel anisotropy is also significant in the lower MTZ, which may contribute to shear wave splitting observations. A low-V body extending down to the lower mantle is visible under the Hainan volcano far away from the plate boundaries, suggesting that Hainan is a hot spot fed by a lower-mantle plume. The low-V body under Hainan is connected with low-V zones in the upper mantle under SE Tibet and Vietnam. Our P wave anisotropy results reflect significant mantle flow existing in the asthenosphere from SE Tibet to Hainan and further southwestward to Vietnam. The present study, especially the 3-D P wave anisotropy results, provides important new insight into mantle dynamics in SE Asia.

  6. Dual subduction tectonics and plate dynamics of central Japan shown by three-dimensional P-wave anisotropic structure

    NASA Astrophysics Data System (ADS)

    Ishise, Motoko; Miyake, Hiroe; Koketsu, Kazuki

    2015-07-01

    The central Japanese subduction zone is characterized by a complex tectonic setting affected by the dual subduction of oceanic plates and collisions between the island arcs. To better understand of the subduction system, we performed an anisotropic tomography analysis using P-wave arrival times from local earthquakes to determine the three-dimensional structure of P-wave azimuthal anisotropy in the overriding plate and the Pacific and Philippine Sea (PHS) slabs. The principal characteristics of anisotropy in the subducted and subducting plates are (1) in the overriding plate, the distribution pattern of fast direction of crustal anisotropy coincides with that of the strike of geological structure, (2) in the two oceanic plates, fast propagation directions of P-wave were sub-parallel to the directions of seafloor spreading. Additionally, our tomographic images demonstrate that (1) the bottom of the Median Tectonic Line, the longest fault zone in Japan, reaches to the lower crust, and seems to link to the source region of an inter-plate earthquake along the PHS slab, (2) the segmentation of the PHS slab - the Izu Islands arc, the Nishi-Shichito ridge, and the Shikoku basin - due to the formation history, is reflected in the regional variation of anisotropy. The tomographic study further implies that there might be a fragment of the Pacific slab suggested by a previous study beneath the Tokyo metropolitan area. The overall findings strongly indicate that seismic anisotropy analysis provide potentially useful information to understand a subduction zone.

  7. Time resolved study of light emitted by detonation arrival at the surface of high explosives in various environments

    NASA Astrophysics Data System (ADS)

    Bahl, Kerry L.; Vonholle, William G.

    1988-03-01

    In search of a way to accurately measure time of arrival of detonation fronts, we have been using an electronic streak camera equipped with a light intensifier to record intensity-time histories of the light that is emitted when a detonation front emerges through the surface of high explosives in contact with various environments. Streak records at writing speeds up to 100 mm/microsec were obtained of detonations in air, argon, water and vacuum when the high explosive (HE) was either bare or covered with materials such as: aluminum silicofluoride (Al2(SiF6)3), PETN powder, polymethyl methacrylate (PMM), glass, aluminum foils, transparent tape, black ink, potassium chloride crystals, sodium chloride crystals and lithium fluoride crystals. The result of this study is that we believe that we can measure the time of arrival of a detonation front at a bare HE surface in air to within a few nanoseconds.

  8. Predicting the Arrival Time of Coronal Mass Ejections with the Graduated Cylindrical Shell and Drag Force Model

    NASA Astrophysics Data System (ADS)

    Shi, Tong; Wang, Yikang; Wan, Linfeng; Cheng, Xin; Ding, Mingde; Zhang, Jie

    2015-06-01

    Accurately predicting the arrival of coronal mass ejections (CMEs) to the Earth based on remote images is of critical significance for the study of space weather. In this paper, we make a statistical study of 21 Earth-directed CMEs, specifically exploring the relationship between CME initial speeds and transit times. The initial speed of a CME is obtained by fitting the CME with the Graduated Cylindrical Shell model and is thus free of projection effects. We then use the drag force model to fit results of the transit time versus the initial speed. By adopting different drag regimes, i.e., the viscous, aerodynamics, and hybrid regimes, we get similar results, with a least mean estimation error of the hybrid model of 12.9 hr. CMEs with a propagation angle (the angle between the propagation direction and the Sun-Earth line) larger than their half-angular widths arrive at the Earth with an angular deviation caused by factors other than the radial solar wind drag. The drag force model cannot be reliably applied to such events. If we exclude these events in the sample, the prediction accuracy can be improved, i.e., the estimation error reduces to 6.8 hr. This work suggests that it is viable to predict the arrival time of CMEs to the Earth based on the initial parameters with fairly good accuracy. Thus, it provides a method of forecasting space weather 1-5 days following the occurrence of CMEs.

  9. The NANOGrav Nine-year Data Set: Observations, Arrival Time Measurements, and Analysis of 37 Millisecond Pulsars

    NASA Astrophysics Data System (ADS)

    The NANOGrav Collaboration; Arzoumanian, Zaven; Brazier, Adam; Burke-Spolaor, Sarah; Chamberlin, Sydney; Chatterjee, Shami; Christy, Brian; Cordes, James M.; Cornish, Neil; Crowter, Kathryn; Demorest, Paul B.; Dolch, Timothy; Ellis, Justin A.; Ferdman, Robert D.; Fonseca, Emmanuel; Garver-Daniels, Nathan; Gonzalez, Marjorie E.; Jenet, Fredrick A.; Jones, Glenn; Jones, Megan L.; Kaspi, Victoria M.; Koop, Michael; Lam, Michael T.; Lazio, T. Joseph W.; Levin, Lina; Lommen, Andrea N.; Lorimer, Duncan R.; Luo, Jing; Lynch, Ryan S.; Madison, Dustin; McLaughlin, Maura A.; McWilliams, Sean T.; Nice, David J.; Palliyaguru, Nipuni; Pennucci, Timothy T.; Ransom, Scott M.; Siemens, Xavier; Stairs, Ingrid H.; Stinebring, Daniel R.; Stovall, Kevin; Swiggum, Joseph K.; Vallisneri, Michele; van Haasteren, Rutger; Wang, Yan; Zhu, Weiwei

    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.

  10. Firstorder ray tracing for qP waves in inhomogeneous weakly anisotropic media

    E-print Network

    Cerveny, Vlastislav

    First­order ray tracing for qP waves in inhomogeneous weakly anisotropic media Vâ??eronique Farra 1 Approximate ray tracing and dynamic ray tracing equations for a qP wave propagating in a smooth inhomogeneous tracing and dynamic ray tracing equations are of the first order, travel time correction calculated along

  11. Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

    DOEpatents

    Benjamin, R.F.

    1983-10-18

    An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

  12. Connecting speeds, directions and arrival times of 22 coronal mass ejections from the sun to 1 AU

    SciTech Connect

    Möstl, C.; Veronig, A. M.; Rollett, T.; Temmer, M.; Peinhart, V.; Amla, K.; Hall, J. R.; Liewer, P. C.; De Jong, E. M.; Colaninno, R. C.; Davies, J. A.; Harrison, R. A.; Lugaz, N.; Farrugia, C. J.; Galvin, A. B.; Liu, Y. D.; Luhmann, J. G.; Vršnak, B.

    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-?, 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.

  13. Connecting Speeds, Directions and Arrival Times of 22 Coronal Mass Ejections from the Sun to 1 AU

    NASA Astrophysics Data System (ADS)

    Möstl, C.; Amla, K.; Hall, J. R.; Liewer, P. C.; De Jong, E. M.; Colaninno, R. C.; Veronig, A. M.; Rollett, T.; Temmer, M.; Peinhart, V.; Davies, J. A.; Lugaz, N.; Liu, Y. D.; Farrugia, C. J.; Luhmann, J. G.; Vršnak, B.; Harrison, R. A.; Galvin, A. B.

    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-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-?, 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-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-1. These results are important for Solar Orbiter and a space weather mission positioned away from the Sun-Earth line.

  14. Position surveillance using one active ranging satellite and time-of-arrival of a signal from an independent satellite

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.; Frey, R. L.; Lewis, J. R.

    1980-01-01

    Position surveillance using one active ranging/communication satellite and the time-of-arrival of signals from an independent satellite was shown to be feasible and practical. A towboat on the Mississippi River was equipped with a tone-code ranging transponder and a receiver tuned to the timing signals of the GOES satellite. A similar transponder was located at the office of the towing company. Tone-code ranging interrogations were transmitted from the General Electric Earth Station Laboratory through ATS-6 to the towboat and to the ground truth transponder office. Their automatic responses included digital transmissions of time-of-arrival measurements derived from the GOES signals. The Earth Station Laboratory determined ranges from the satellites to the towboat and computed position fixes. The ATS-6 lines-of-position were more precise than 0.1 NMi, 1 sigma, and the GOES lines-of-position were more precise than 1.6 NMi, 1 sigma. High quality voice communications were accomplished with the transponders using a nondirectional antenna on the towboat. The simple and effective surveillance technique merits further evaluation using operational maritime satellites.

  15. Vortex structure in p-wave superconductors

    NASA Astrophysics Data System (ADS)

    Alama, Stan; Bronsard, Lia; Lamy, Xavier

    2015-11-01

    We study vortices in p-wave superconductors in a Ginzburg-Landau setting. The state of the superconductor is described by a pair of complex wave functions, and the p-wave symmetric energy functional couples these in both the kinetic (gradient) and potential energy terms, giving rise to systems of partial differential equations which are nonlinear and coupled in their second derivative terms. We prove the existence of energy minimizing solutions in bounded domains ? ? ?2 and consider the existence and qualitative properties (such as the asymptotic behavior) of equivariant solutions defined in all of ?2. The coupling of the equations at highest order changes the nature of the solutions, and many of the usual properties of classical Ginzburg-Landau vortices either do not hold for the p-wave solutions or are not immediately evident.

  16. On the possibility to discriminate the mass of the primary cosmic ray using the muon arrival times from extensive air showers: Application for Pierre Auger Observatory

    SciTech Connect

    Arsene, N.; Rebel, H.; Sima, O.

    2012-11-20

    In this paper we study the possibility to discriminate the mass of the primary cosmic ray by observing the muon arrival times in ground detectors. We analyzed extensive air showers (EAS) induced by proton and iron nuclei with the same energy 8 Multiplication-Sign 10{sup 17} eV simulated with CORSIKA, and analyzed the muon arrival times at ground measured by the infill array detectors of the Pierre Auger Observatory (PAO). From the arrival times of the core and of the muons the atmospheric depth of muon generation locus is evaluated. The results suggest a potential mass discrimination on the basis of muon arrival times and of the reconstructed atmospheric depth of muon production. An analysis of a larger set of CORSIKA simulations carried out for primary energies above 10{sup 18} eV is in progress.

  17. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...record departure/arrival dates and times on my travel claim? 301-11.10 Section 301-11...Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES ALLOWABLE TRAVEL EXPENSES...

  18. The energy radiated by the 26 December 2004 Sumatra-Andaman earthquake estimated from 10-minute P-wave windows

    USGS Publications Warehouse

    Choy, G.L.; Boatwright, J.

    2007-01-01

    The rupture process of the Mw 9.1 Sumatra-Andaman earthquake lasted for approximately 500 sec, nearly twice as long as the teleseismic time windows between the P and PP arrival times generally used to compute radiated energy. In order to measure the P waves radiated by the entire earthquake, we analyze records that extend from the P-wave to the S-wave arrival times from stations at distances ?? >60??. These 8- to 10-min windows contain the PP, PPP, and ScP arrivals, along with other multiply reflected phases. To gauge the effect of including these additional phases, we form the spectral ratio of the source spectrum estimated from extended windows (between TP and TS) to the source spectrum estimated from normal windows (between TP and TPP). The extended windows are analyzed as though they contained only the P-pP-sP wave group. We analyze four smaller earthquakes that occurred in the vicinity of the Mw 9.1 mainshock, with similar depths and focal mechanisms. These smaller events range in magnitude from an Mw 6.0 aftershock of 9 January 2005 to the Mw 8.6 Nias earthquake that occurred to the south of the Sumatra-Andaman earthquake on 28 March 2005. We average the spectral ratios for these four events to obtain a frequency-dependent operator for the extended windows. We then correct the source spectrum estimated from the extended records of the 26 December 2004 mainshock to obtain a complete or corrected source spectrum for the entire rupture process (???600 sec) of the great Sumatra-Andaman earthquake. Our estimate of the total seismic energy radiated by this earthquake is 1.4 ?? 1017 J. When we compare the corrected source spectrum for the entire earthquake to the source spectrum from the first ???250 sec of the rupture process (obtained from normal teleseismic windows), we find that the mainshock radiated much more seismic energy in the first half of the rupture process than in the second half, especially over the period range from 3 sec to 40 sec.

  19. Acousto-ultrasonic input-output characterization of unidirectional fiber composite plate by P waves

    NASA Technical Reports Server (NTRS)

    Liao, Peter; Williams, James H., Jr.

    1988-01-01

    The single reflection problem for an incident P wave at a stress free plane boundary in a semi-infinite transversely isotropic medium whose isotropic plane is parallel to the plane boundary is analyzed. It is found that an obliquely incident P wave results in a reflected P wave and a reflected SV wave. The delay time for propagation between the transmitting and the receiving transducers is computed as if the P waves were propagating in an infinite half space. The displacements associated with the P waves in the plate and which may be detected by a noncontact NDE receiving transducer are approximated by an asymptotic solution for an infinite transversely isotropic medium subjected to a harmonic point load.

  20. Decay constants of $P$-wave mesons

    E-print Network

    Guo-Li Wang

    2007-05-18

    Decay constants of $P$-wave mesons are computed in the framework of instantaneous Bethe-Salpeter method (Salpeter method). By analyzing the parity and possible charge conjugation parity, we give the relativistic configurations of wave functions with definite parity and possible charge conjugation parity. With these wave functions as input, the full Salpeter equations for different $P$-wave states are solved, and the mass spectra as well as the numerical values of wave functions are obtained. Finally we compute the leptonic decay constants of heavy-heavy and heavy-light $^3P_0$, $^3P_1$ and $^1P_1$ states.

  1. Gamma-Ray Burst Arrival Time Localizations: Simultaneous Observations by Mars Observer, Compton Gamma Ray Observatory and Ulysses

    NASA Technical Reports Server (NTRS)

    Laros, J. G.; Boynton, W. V.; Hurley, K.; Kouveliotou, C.; McCollough, M. L.; Fishman, G. J.; Meegan, C. A.

    1997-01-01

    Between 1992 October 4 and 1993 August 1, concurrent coverage by the Compton Gamma Ray Observatory (CGRO), Mars Observer (MO), and Ulysses spacecraft was obtained for 78 gamma-ray bursts (GRBs). Although most of these were below the MO and Ulysses thresholds, nine were positively detected by all three spacecraft, with data quality adequate for quantitative localization analysis. All were localized independently to approximately 2 deg accuracy by the CGRO Burst and Transient Source Experiment (BATSE). We computed arrival-time error boxes with larger dimensions ranging from a few arcminutes to the diameters of the BATSE-only boxes and with smaller dimensions in the arcminute range. Three events are of particular interest: GB 930704 (BATSE 2428) has been described as a possible repeater. The arrival-time information is consistent with that hypothesis, but only just so. The GB 930706 (2431) box, at approximately 1 min x 4 min, is the only one this small obtained since Pioneer Venus Orbiter (PVO) entered the Venusian atmosphere in 1992 October. Sensitive radio and optical observations of this location were made within 8 and 9 days of the burst, but no counterpart candidates were identified. GB 930801 (2477) is the first GRB that had its localization improved by taking into account BATSE Earth occultation.

  2. Predicting the Arrival Time of Coronal Mass Ejections with the Graduated Cylindrical Shell and Drag Force Model

    E-print Network

    Shi, Tong; Wan, Linfeng; Cheng, Xin; Ding, Mingde; Zhang, Jie

    2015-01-01

    Accurately predicting the arrival of coronal mass ejections (CMEs) at the Earth based on remote images is of critical significance in the study of space weather. In this paper, we make a statistical study of 21 Earth directed CMEs, exploring in particular the relationship between CME initial speeds and transit times. The initial speed of a CME is obtained by fitting the CME with the Graduated Cylindrical Shell model and is thus free of projection effects. We then use the drag force model to fit results of the transit time versus the initial speed. By adopting different drag regimes, i.e., the viscous, aerodynamics, and hybrid regimes, we get similar results, with the least mean estimation error of the hybrid model of 12.9 hours. CMEs with a propagation angle (the angle between the propagation direction and the Sun-Earth line) larger than its half angular width arrive at the Earth with an angular deviation caused by factors other than the radial solar wind drag. The drag force model cannot be well applied to s...

  3. ESTIMATING THE ARRIVAL TIME OF EARTH-DIRECTED CORONAL MASS EJECTIONS AT IN SITU SPACECRAFT USING COR AND HI OBSERVATIONS FROM STEREO

    SciTech Connect

    Mishra, Wageesh; Srivastava, Nandita

    2013-07-20

    Predicting the arrival time and transit speed of coronal mass ejections (CMEs) near the Earth is critical to understanding the solar-terrestrial relationship. Even though STEREO observations now provide multiple views of CMEs in the heliosphere, the true speeds derived from stereoscopic reconstruction of SECCHI coronagraph data are not quite sufficient for accurate forecasting of the arrival time at Earth of a majority of CMEs. This uncertainty is due to many factors that change CME kinematics, such as the interaction of two or more CMEs or the interaction of CMEs with the pervading solar wind. In order to understand the propagation of CMEs, we have used the three-dimensional triangulation method on SECCHI coronagraph (COR2) images and geometric triangulation on the J-maps constructed from Heliospheric Imagers HI1 and HI2 data for eight Earth-directed CMEs observed during 2008-2010. Based on the reconstruction, and implementing the drag-based model for the distance where the CMEs could not be tracked unambiguously in the interplanetary (IP) medium, the arrival time of these CMEs have been estimated. These arrival times have also been compared with the actual arrival times as observed by in situ instruments. The analysis reveals the importance of heliospheric imaging for improved forecasting of the arrival time and direction of propagation of CMEs in the IP medium.

  4. Constraining the Size and Depth of a Shallow Crustal Magma Body at Newberry Volcano Using P-Wave Tomography and Finite-Difference Waveform Modeling

    NASA Astrophysics Data System (ADS)

    Beachly, M. W.; Hooft, E. E.; Toomey, D. R.; Waite, G. P.

    2011-12-01

    Imaging magmatic systems improves our understanding of magma ascent and storage in the crust and contributes to hazard assessment. Seismic tomography reveals crustal magma bodies as regions of low velocity; however the ability of delay-time tomography to detect small, low-velocity bodies is limited by wavefront healing. Alternatively, crustal magma chambers have been identified from secondary phases including P and S wave reflections and conversions. We use a combination of P-wave tomography and finite-difference waveform modeling to characterize a shallow crustal magma body at Newberry Volcano, central Oregon. Newberry's eruptions are silicic within the central caldera and mafic on its periphery suggesting a central silicic magma storage system. The system may still be active with a recent eruption ~1300 years ago and a drill hole temperature of 256° C at only 932 m depth. A low-velocity anomaly previously imaged at 3-5 km beneath the caldera indicates either a magma body or a fractured pluton. With the goal of detecting secondary arrivals from a magma chamber beneath Newberry Volcano, we deployed a line of densely-spaced (~300 m), three-component seismometers that recorded a shot of opportunity from the High Lava Plains Experiment in 2008. The data record a secondary P-wave arrival originating from beneath the caldera. In addition we combine travel-time data from our 2008 experiment with data collected in the 1980's by the USGS for a P-wave tomography inversion to image velocity structure to 6 km depth. The inversion includes 16 active sources, 322 receivers and 1007 P-wave first arrivals. The tomography results reveal a high-velocity, ring-like anomaly beneath the caldera ring faults to 2 km depth that surrounds a shallow low-velocity region. Beneath 2.5 km high-velocity anomalies are concentrated east and west of the caldera. A central low-velocity body lies below 3 km depth. Tomographic inversions of synthetic data suggest that the central low-velocity body beneath 3 km depth is not well resolved and that, for example, an unrealistically large low-velocity body with a volume up to 72 km3 at 40% velocity reduction (representing 30±7% partial melt) could be consistent with the observed travel-times. We use the tomographically derived velocity structure to construct 2D finite difference models and include synthetic low-velocity bodies in these models to test various magma chamber geometries and melt contents. Waveform modeling identifies the observed secondary phase as a transmitted P-wave formed by delaying and focusing P-wave energy through the low-velocity region. We will further constrain the size and shape of the low-velocity region by comparing arrival times and amplitudes of observed and synthetic primary and secondary phases. Secondary arrivals provide compelling evidence for an active crustal magmatic system beneath Newberry volcano and demonstrate the ability of waveform modeling to constrain the nature of magma bodies beyond the limits of seismic tomography.

  5. Zero-bias anomaly in p-wave superconductor

    NASA Astrophysics Data System (ADS)

    Rosenstein, Baruch; Shapiro, B. Ya.; Shapiro, I.; Li, Dingping

    2015-11-01

    It was shown some time ago that a magnetic field penetrates a triplet non-chiral superconductor described by the (three-dimensional) vector order parameter as an array of magnetic skyrmions, a texture carrying two units of magnetic flux. Magnetic skyrmions do not have a normal core in contrast to Abrikosov vortices. The spectrum of Andreev midgap states of this coreless topological defect in p-wave isotropic superconductors with single parabolic band is calculated. It is shown that a magnetic field can be used to tune the Andreev state energy precisely to zero (these states are not topologically protected). They can be further stabilized and manipulated by pinning of the skyrmions on columnar defects or nanoholes. In contrast to Majorana modes in chiral p-wave superconductor, the tunneling between ZES within neighboring skyrmions is prohibited due to their high angular momentum. Experimental signatures of these states are discussed.

  6. Long range p -wave proximity effect into a disordered metal

    NASA Astrophysics Data System (ADS)

    Keser, Aydin Cem; Stanev, Valentin; Galitski, Victor

    2015-03-01

    We use quasiclassical methods of superconductivity to study the superconducting proximity effect from a topological p -wave superconductor into a disordered quasi-one-dimensional metallic wire. We demonstrate that the corresponding Eilenberger equations with disorder reduce to a closed nonlinear equation for the superconducting component of the matrix Green's function. Remarkably, this equation is formally equivalent to a classical mechanical system (i.e., Newton's equations), with the Green function corresponding to a coordinate of a fictitious particle and the coordinate along the wire corresponding to time. This mapping allows us to obtain exact solutions in the disordered nanowire in terms of elliptic functions. A surprising result that comes out of this solution is that the p -wave superconductivity proximity induced into the disordered metal remains long range, decaying as slowly as the conventional s -wave superconductivity. It is also shown that impurity scattering leads to the appearance of a zero-energy peak.

  7. Development of the town data base: Estimates of exposure rates and times of fallout arrival near the Nevada Test Site

    SciTech Connect

    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.

  8. Interstellar modulation of the flux density and arrival time of pulses from pulsar B 1937+214

    NASA Astrophysics Data System (ADS)

    Lestrade, J.-F.; Rickett, B. J.; Cognard, I.

    1998-06-01

    Observations of the millisecond pulsar B1937+214 made at Nan\\c cay over 6 years show 30% rms flux variations over 13 +/- 4 days due to Refractive Interstellar Scintillations. The arrival times (TOA) also show variations over a similar time scale 16 +/- 10 days with an rms amplitude of about 0.3mu secs. These ``rapid'' TOA variations are anti-correlated ( ~ -40%) with the flux and so are also caused by propagation through the ionized interstellar medium. The correlation is such that weak pulses tend to arrive late. While TOA modulations due to changing geometric delay should be positively correlated with flux, those due to small scale variations in the dispersive delay should be negatively correlated with the flux and so are presumed to be responsible in our observations. The level and time scales are shown to be consistent with expectations based on the Kolmogorov model of the interstellar density spectrum. However, in the data there is a sequence of about 5 discrete events, in which the flux remains low over 10-30 days and the TOA is on average late but also shows rapid variations. Assuming that these are indeed discrete events, we interpret them as due to isolated regions of enhanced plasma density crossing the line of sight. Such ``Extreme Scattering Events'' make a major contribution to the TOA variations and their anti-correlations with the observed flux. They are seen against a background of the normal refractive scintillation. A model is proposed in which discrete sheets of plasma cross the line of sight and cause a ``de-focussing'' event when aligned parallel to the line of sight. The statistics of the events imply a surprisingly large space density of the sheets; an alternative is that by chance we view PSR B1937+214 tangentially through a supernova shell which is fragmented and so causes multiple events.

  9. One dimensional P wave velocity structure of the crust beneath west Java and accurate hypocentre locations from local earthquake inversion

    SciTech Connect

    Supardiyono; Santosa, Bagus Jaya

    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.

  10. Deriving the orbital properties of pulsators in binary systems through their light arrival time delays

    NASA Astrophysics Data System (ADS)

    Murphy, Simon J.; Shibahashi, Hiromoto

    2015-07-01

    We present the latest developments to the phase modulation method for finding binaries among pulsating stars. We demonstrate how the orbital elements of a pulsating binary star can be obtained analytically, that is, without converting time delays to radial velocities by numerical differentiation. Using the time delays directly offers greater precision, and allows the parameters of much smaller orbits to be derived. The method is applied to KIC 9651065, KIC 10990452 and KIC 8264492, and a set of the orbital parameters is obtained for each system. Radial velocity curves for these stars are deduced from the orbital elements thus obtained.

  11. Practical and fast quantum random number generation based on photon arrival time relative to external reference

    SciTech Connect

    Nie, You-Qi; Zhang, Jun Pan, Jian-Wei; Zhang, Hong-Fei; Wang, Jian; Zhang, Zhen; Ma, Xiongfeng

    2014-02-03

    We present a practical high-speed quantum random number generator, where the timing of single-photon detection relative to an external time reference is measured as the raw data. The bias of the raw data can be substantially reduced compared with the previous realizations. The raw random bit rate of our generator can reach 109 Mbps. We develop a model for the generator and evaluate the min-entropy of the raw data. Toeplitz matrix hashing is applied for randomness extraction, after which the final random bits are able to pass the standard randomness tests.

  12. POSITIONING USING TIME-DIFFERENCE OF ARRIVAL MEASUREMENTS Fredrik Gustafsson and Fredrik Gunnarsson

    E-print Network

    Gustafsson, Fredrik

    's (0.4, 0.6 and 0.9 scale units, respectively). · Electronic warfare, where the problem) measurements occurs in a range of ap- plications from wireless communication networks to elec- tronic warfare time is unknown, or it can be unknown, as is the case in electronic war- fare. In either case, i cannot

  13. Predicting spike times of a detailed conductance-based neuron model driven by stochastic spike arrival

    E-print Network

    Gerstner, Wulfram

    models of neuronal activity such as integrate-and-fire models allow a description of neuronal dynamics% of the postsynaptic action potentials can be predicted with the correct timing by the integrate-and-fire-type model. The modified spike response model is based upon a linearized theory of conductance-driven integrate-and-fire

  14. Effect of method and timing of castration on newly arrived stocker cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An experiment was conducted to determine the effects of castration method and timing on the performance and health of newly received stocker cattle. Two hundred and seventy-one crossbred male calves (184 bulls, 87 steers; 210 ± 14.7 kg) were purchased at auction barns and shipped in three groups. ...

  15. Investigating the Dependence of Fractal Dimension on Raindrop Size for Drop Arrival Times As Measured By a Two-Dimensional Video Disdrometer

    NASA Astrophysics Data System (ADS)

    Lemasters, R. D.; Larsen, M.

    2014-12-01

    There is empirical evidence that large raindrop arrival times are not perfectly random. As a way to characterize this behavior, it has been suggested that raindrop arrival times may be well described by fractal statistics. Two-Dimensional Video Disdrometer data with millisecond resolution was used to construct an ensemble of time series, each of which was associated with a small range of drop diameters for an individual storm. The monofractal dimension was determined for each of these time series. It is apparent that the fractal dimension has a clear dependence on drop size. This drop size dependence, as well as storm to storm variabilitiy, is explored.

  16. Smolt Condition and Timing of Arrival at Lower Granite Reservoir, 1984 Annual Report.

    SciTech Connect

    Scully, Richard J.; Buettner, Edwin W.

    1986-02-01

    Hatcheries released 9.3 million chinook salmon and 6.3 million steelhead smolts and presmolts upriver from Lower Granite Reservoir for migration in spring, 1984. Peak passage of yearling chinook salmon occurred the third week in April at both Whitebird and Snake River traps. Passage of steelhead was still increasing when high water stopped trapping in mid-May. Average migration rate between release sites and Snake River (the head of Lower Granite Reservoir) was 13.2 miles/day and from that point on through the reservoir to the dam, 1.9 miles/day. Salmon River discharge, when considered along with other environmental factors, had the greatest effect on migration rate of smolts branded both at hatcheries and at the Whitebird trap and migrating to the head of Lower Granite Reservoir. Migration rate for steelhead released from Dworshak Hatchery and recaptured at the Clearwater trap was 34 miles/day. Survival rates to the Snake River trap of branded chinook salmon smolts released at Hells Canyon Dam, Rapid River, South Fork Salmon and Decker Flat were 52%, 65%, 68% and 35%, respectively. Classical descaling, where at least 40% of the scales are missing from at least two of five areas on the side of a smolt, ranged from 0 to 5.3% at hatcheries for chinook salmon and was less than 1% for steelhead. Scattered descaling, where at least 10% of scales are missing from at least one side of a fish, was always more extensive than was classical descaling, ranging from 2.5 times greater for Clearwater hatchery steelhead to 6.8 times greater for Clearwater wild steelhead. Mean total length of chinook salmon yearlings was the same at all the traps, i.e., 128 mm (117 mm fork length) +- 1 mm.

  17. Landing together: How flocks arrive at a coherent action in time and space in the presence of perturbations

    NASA Astrophysics Data System (ADS)

    Ferdinandy, B.; Bhattacharya, K.; Ábel, D.; Vicsek, T.

    2012-02-01

    Collective motion is abundant in nature, producing a vast amount of phenomena which have been studied in recent years, including the landing of flocks of birds. We investigate the collective decision making scenario where a flock of birds decides the optimal time of landing in the absence of a global leader. We introduce a simple phenomenological model in the spirit of the statistical mechanics-based self-propelled particles (SPPs) approach to interpret this process. We expect that our model is applicable to a larger class of spatiotemporal decision making situations than just the landing of flocks (which process is used as a paradigmatic case). In the model birds are only influenced by observable variables, like position and velocity. Heterogeneity is introduced in the flock in terms of a depletion time after which a bird feels increasing bias to move towards the ground. Our model demonstrates a possible mechanism by which animals in a large group can arrive at an egalitarian decision about the time of switching from one activity to another in the absence of a leader. In particular, we show the existence of a paradoxical effect where noise enhances the coherence of the landing process.

  18. Joint inversion of gravity and arrival time data from Parkfield: New constraints on structure and hypocenter locations near the SAFOD drill site

    USGS Publications Warehouse

    Roecker, S.; Thurber, C.; McPhee, D.

    2004-01-01

    Taking advantage of large datasets of both gravity and elastic wave arrival time observations available for the Parkfield, California region, we generated an image consistent with both types of data. Among a variety of strategies, the best result was obtained from a simultaneous inversion with a stability requirement that encouraged the perturbed model to remain close to a starting model consisting of a best fit to the arrival time data. The preferred model looks essentially the same as the best-fit arrival time model in areas where ray coverage is dense, with differences being greatest at shallow depths and near the edges of the model where ray paths are few. Earthquake locations change by no more than about 100 m, the general effect being migration of the seismic zone to the northeast, closer to the surface trace of the San Andreas Fault. Copyright 2004 by the American Geophysical Union.

  19. ARRIVAL TIME CALCULATION FOR INTERPLANETARY CORONAL MASS EJECTIONS WITH CIRCULAR FRONTS AND APPLICATION TO STEREO OBSERVATIONS OF THE 2009 FEBRUARY 13 ERUPTION

    SciTech Connect

    Moestl, C.; Rollett, T.; Temmer, M.; Veronig, A. M.; Biernat, H. K.; Lugaz, N.; Farrugia, C. J.; Galvin, A. B.; Davies, J. A.; Harrison, R. A.; Crothers, S.; Luhmann, J. G.; Zhang, T. L.; Baumjohann, W.

    2011-11-01

    One of the goals of the NASA Solar TErestrial RElations Observatory (STEREO) mission is to study the feasibility of forecasting the direction, arrival time, and internal structure of solar coronal mass ejections (CMEs) from a vantage point outside the Sun-Earth line. Through a case study, we discuss the arrival time calculation of interplanetary CMEs (ICMEs) in the ecliptic plane using data from STEREO/SECCHI at large elongations from the Sun in combination with different geometric assumptions about the ICME front shape [fixed-{Phi} (FP): a point and harmonic mean (HM): a circle]. These forecasting techniques use single-spacecraft imaging data and are based on the assumption of constant velocity and direction. We show that for the slow (350 km s{sup -1}) ICME on 2009 February 13-18, observed at quadrature by the two STEREO spacecraft, the results for the arrival time given by the HM approximation are more accurate by 12 hr than those for FP in comparison to in situ observations of solar wind plasma and magnetic field parameters by STEREO/IMPACT/PLASTIC, and by 6 hr for the arrival time at Venus Express (MAG). We propose that the improvement is directly related to the ICME front shape being more accurately described by HM for an ICME with a low inclination of its symmetry axis to the ecliptic. In this case, the ICME has to be tracked to >30{sup 0} elongation to obtain arrival time errors < {+-} 5 hr. A newly derived formula for calculating arrival times with the HM method is also useful for a triangulation technique assuming the same geometry.

  20. Connecting speeds, directions and arrival times of 22 coronal mass ejections from the Sun to 1 AU

    E-print Network

    Möstl, C; Hall, J R; Liewer, P C; De Jong, E M; Colaninno, R C; Veronig, A M; Rollett, T; Temmer, M; Peinhart, V; Davies, J A; Lugaz, N; Liu, Y D; Farrugia, C J; Luhmann, J G; Vršnak, B; Harrison, R A; Galvin, A B

    2014-01-01

    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 $2700 \\: km \\: s^{-1}$). We track the CMEs to $34.9 \\pm 7.1$ degrees elongation from the Sun with J-maps constructed using the SATPLOT tool, resulting in prediction lead times of $-26.4 \\pm 15.3$ hours. The geometrical models we use assume different CME front shapes (Fixed-$\\Phi$, Harmonic Mean, S...

  1. Anomalous delays of teleseismic P waves in Yellowstone National Park

    USGS Publications Warehouse

    Iyer, H.M.

    1975-01-01

    TELESEISMIC P waves recorded by a short-period seismic network, comprising 12 stations, in Yellowstone National Park, show anomalous delays of 1-2 s in their travel times in the central region of the park relative to the surrounding area. To explain this phenomenon, I propose that a substantial body of low velocity material is present beneath the park, with horizontal dimensions of several tens of kilometres; it may be the magma chamber associated with the volcanism of Yellowstone (ref. 1, and G. P. Eaton et al., unpublished). ?? 1975 Nature Publishing Group.

  2. P-Wave Electron-Hydrogen Scattering

    NASA Technical Reports Server (NTRS)

    Bhtia, Anand

    2012-01-01

    A variational wave function incorporating short range correlations via Hylleraas type functions plus long-range polarization terms of the polarized orbital type but with smooth cut-off factors has been used to calculate P-wave phase shifts for electron-hydrogen scattering. This approach gives the direct r(exp -4) potential and a non-local optical potential which is definite. The resulting phase shifts have rigorous lower bounds and the convergence is much faster than those obtained without the modification of the target function. Final results will be presented at the conference.

  3. P-wave electron-hydrogen scattering

    NASA Astrophysics Data System (ADS)

    Bhatia, Anand

    2012-06-01

    A variational wave function incorporating short range correlations via Hylleraas type functions plus long-range polarization terms of the polarized orbital type but with smooth cut-off factors has been used to calculate P-wave phase shifts for electron-hydrogen scattering. This approach gives the direct r-4 potential and a non-local optical potential which is negative definite. The resulting phase shifts have rigorous lower bounds and the convergence is much faster than those obtained without the modification of the target function. Final results will be presented at the conference.

  4. P wave dispersion in patients with hypochondriasis.

    PubMed

    Atmaca, Murad; Korkmaz, Hasan; Korkmaz, Sevda

    2010-11-26

    P wave dispersion (Pd), defined as the difference between the maximum and the minimum P wave duration, has been associated with anxiety. Thus, we wondered whether Pd in hypochondriasis which is associated with anxiety differed from that in healthy controls. Pd was measured in 30 hypochondriac patients and same number of physically and mentally healthy age- and gender-matched controls. Hamilton Depression Rating (HDRS) and Hamilton Anxiety Rating Scales (HARS) were scored. The heart rate and left atrium (LA) sizes were not significantly different between groups. However, both Pmax and Pmin values of the patients were significantly higher than those of healthy controls. As for the main variable investigated in the present study, the corrected Pd was significantly longer in the patient group compared to control group. On the basis of this study, we can conclude that Pd may be related to hypochondriasis though our sample is too small to allow us to obtain a clear conclusion. Future studies with larger sample evaluating the effects of treatment are required. PMID:20813155

  5. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... departure/arrival dates and times on my travel claim? 301-11.10 Section 301-11.10 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES ALLOWABLE TRAVEL EXPENSES 11-PER DIEM EXPENSES General Rules § 301-11.10 Am I required to record...

  6. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... departure/arrival dates and times on my travel claim? 301-11.10 Section 301-11.10 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES ALLOWABLE TRAVEL EXPENSES 11-PER DIEM EXPENSES General Rules § 301-11.10 Am I required to record...

  7. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... departure/arrival dates and times on my travel claim? 301-11.10 Section 301-11.10 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES ALLOWABLE TRAVEL EXPENSES 11-PER DIEM EXPENSES General Rules § 301-11.10 Am I required to record...

  8. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... departure/arrival dates and times on my travel claim? 301-11.10 Section 301-11.10 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES ALLOWABLE TRAVEL EXPENSES 11-PER DIEM EXPENSES General Rules § 301-11.10 Am I required to record...

  9. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... departure/arrival dates and times on my travel claim? 301-11.10 Section 301-11.10 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES ALLOWABLE TRAVEL EXPENSES 11-PER DIEM EXPENSES General Rules § 301-11.10 Am I required to record...

  10. Eastern Edge of the Laurentian Cratonic Lithosphere Beneath Southern Quebec from Teleseismic P Waves

    NASA Astrophysics Data System (ADS)

    Menke, W. H.; Neitz, T.; Levin, V. L.; Darbyshire, F. A.; Bastow, I. D.

    2014-12-01

    The eastern margin of Laurentia was deformed by the late-Proterozoic Grenville orogeny, which metamorphosed the original Archean-age cratonic crust and added extensive intrusive rocks. The Laurentian crust clearly extends as far east as the Laurentian Highlands, just north of the St. Laurence River, where Grenville-deformed rocks outcrop. Small outliers of Grenville-deformed rocks amongst west-thrust Paleozoic sediments, 20-50 km east of the Appalachian Front in southern Quebec, suggest that the Laurentian crust extends beneath the shallow thrust sheets of this region, too. On the other hand, Laurentia does not extend east of the Norumbega fault in coastal Maine, for the crust there is derived from the Avalon micro-continent. We search for the eastern edge of Laurentia within this ~250 km wide interval using relative arrival times of teleseismic P waves which ascend sub-vertically through the lithosphere beneath the region. These times are expected to be most sensitive to upper mantle compressional velocity and so to be able to discriminate the cratonic lithosphere on the basis of its faster than average speed. We use signal-correlation techniques to measured delay times for all broadband seismic stations in the region, including the QMIII array, which is especially designed to have high station density near the Appalachian Front. As expected, we observe central Quebec to have anomalously early times and coastal Maine to have anomalously late times, by as much as ±1s, when compared to the predictions of the global AK135 traveltime model. The boundary between the two arrival time regimes is sharp and is collinear with the Appalachian Front, to within the ± 25 km spatial resolution of our study. We hypothesize that it represents the eastern edge of the Laurentian cratonic lithosphere. Tomographic inversion of the data indicates a 0.2 km/s (2.4%) drop in compressional velocity of the shallow (90 km deep) mantle from west to east across the boundary. This is a strong jump in mantle properties, as either a 400 deg C increase in temperature or a 11 decrease in Mg# (or some other as yet unidentified source of heterogeneity) is needed to explain it. Future work will use teleseismic shear waves to further characterize the lithosphere across this boundary.

  11. Chiral p-wave order in Sr2RuO4

    NASA Astrophysics Data System (ADS)

    Kallin, Catherine

    2012-04-01

    Shortly after the discovery in 1994 of superconductivity in Sr2RuO4, it was proposed on theoretical grounds that the superconducting state may have chiral p-wave symmetry analogous to the A phase of superfluid 3He. Substantial experimental evidence has since accumulated in favor of this pairing symmetry, including several interesting recent results related to broken time-reversal symmetry (BTRS) and vortices with half of the usual superconducting flux quantum. Great interest surrounds the possibility of chiral p-wave order in Sr2RuO4, since this state may exhibit topological order analogous to that of a quantum Hall state, and can support such exotic physics as Majorana fermions and non-Abelian winding statistics, which have been proposed as one route to a quantum computer. However, serious discrepancies remain in trying to connect the experimental results to theoretical predictions for chiral p-wave order. In this paper, I review a broad range of experiments on Sr2RuO4 that are sensitive to p-wave pairing, triplet superconductivity and time-reversal symmetry breaking and compare these experiments to each other and to theoretical predictions. In this context, the evidence for triplet pairing is strong, although some puzzles remain. The ‘smoking gun’ experimental results for chiral p-wave order, those which directly look for evidence of BTRS in the superconducting state of Sr2RuO4, are most perplexing when the results are compared with each other and to theoretical predictions. Consequently, the case for chiral p-wave superconductivity in Sr2RuO4 remains unresolved, suggesting the need to consider either significant modifications to the standard chiral p-wave models or possible alternative pairing symmetries. Recent ideas along these lines are discussed.

  12. Investigation of inhomogeneities and anisotropy in the crust and upper mantle of central Europe by means of teleseismic P waves

    NASA Astrophysics Data System (ADS)

    Wylegalla, K.; Bormann, P.; Baumbach, M.

    1988-06-01

    Travel-time residuals from global samples as well as azimuth and slowness deviations of teleseismic P-wave arrivals have been analysed both at the individual seismic stations BRG, CLL, MOX, and PRU, and using the G.D.R. station network. The main results of the analysis are as follows. (1) Azimuth and incidence-angle deviations of short-period P waves have been observed at individual stations by means of three-component measurements. Their transformations into the slowness space reveal a mislocation pattern at all stations, which suggests the superimposition of regional and strong local effects on wave propagation. (2) The mean station residuals, as well as the azimuth dependence of the residuals with a period of 2?, indicate a rising of the upper mantle discontinuities to the north of central Europe to the east European platform. (3) This general trend is confirmed by the mislocation patterns observed at various subnetworks of the telemetric system of seismic stations of the G.D.R. The refined model assumes a dipping of flat discontinuities or isotachs in the upper mantle down to the 20° discontinuity, with a dip angle of about 11° ± 2° north of the network centre and a zero dip south of it. The dip direction is 192° ± 5°. (4) Fourier analysis of the azimuth dependence of travel-time residuals revealed almost the same phase of the second azimuthal term at all individual stations. This fact could be interpreted in terms of an anisotropic layer of some 200 km thickness in the upper mantle assuming a coefficient of anisotropy of 6%. The azimuth of maximum velocity is 10° (+180°) and agrees well with the results derived by Bamford (1977) from Pn-wave measurements.

  13. Crosswell seismic studies in gas hydrate-bearing sediments: P wave velocity and attenuation tomography

    NASA Astrophysics Data System (ADS)

    Bauer, K.; Haberland, Ch.; Pratt, R. G.; Ryberg, T.; Weber, M. H.; Mallik Working Group

    2003-04-01

    We present crosswell seismic data from the Mallik 2002 Production Research Well Program, an international research project on Gas Hydrates in the Northwest Territories of Canada. The program participants include 8 partners; The Geological Survey of Canada (GSC), The Japan National Oil Corporation (JNOC), GeoForschungsZentrum Potsdam (GFZ), United States Geological Survey (USGS), United States Department of the Energy (USDOE), India Ministry of Petroleum and Natural Gas (MOPNG)/Gas Authority of India (GAIL) and the Chevron-BP-Burlington joint venture group. The crosswell seismic measurements were carried out by making use of two 1160 m deep observation wells (Mallik 3L-38 and 4L-38) both 45 m from and co-planar with the 1188 m deep production research well (5L-38). A high power piezo-ceramic source was used to generate sweeped signals with frequencies between 100 and 2000 Hz recorded with arrays of 8 hydrophones per depth level. A depth range between 800 and 1150 m was covered, with shot and receiver spacings of 0.75 m. High quality data could be collected during the survey which allow for application of a wide range of crosswell seismic methods. The initial data analysis included suppression of tube wave energy and picking of first arrivals. A damped least-squares algorithm was used to derive P-wave velocities from the travel time data. Next, t* values were derived from the decay of the amplitude spectra, which served as input parameters for a damped least-squares attenuation tomography. The initial results of the P-wave velocity and attenuation tomography reveal significant features reflecting the stratigraphic environment and allow for detection and eventually quantification of gas hydrate bearing sediments. A prominent correlation between P velocity and attenuation was found for the gas hydrate layers. This contradicts to the apparently more meaningful inverse correlation as it was determined for the gas hydrates at the Blake Ridge but supports the results from the Mallik 2L-38 sonic log data. The P velocities and attenuation values, if combined with other information can be important for the quantitative evaluation of the gas hydrate saturation, and may further constrain petrophysical models of the hydrate bearing sediment formation.

  14. 3D P-wave velocity structure around the rupture area of the 2003 Tokachi-oki earthquake (Mw=8.0) in the margin of the Kuril trench

    NASA Astrophysics Data System (ADS)

    Machida, Y.; Takanami, T.; Murai, Y.; Shinohara, M.; Yamada, T.; Kanazawa, T.; Hirata, N.; Sakai, S.; Mochizuki, K.; Shiobara, H.; Hino, R.; Nishino, M.; Shimizu, H.; Uehira, K.; Kaneda, Y.; Suyehiro, K.; Watanabe, T.; Takahashi, N.; Sato, T.; Araki, E.; Mikada, H.; Uhira, K.

    2006-12-01

    We determined the three dimensional P-wave velocity structure in the rupture area of the 2003 Tokachi-oki earthquake (Mw=8.0) by using P-wave travel time data of the aftershocks and relocated the hypocenters simultaneously. In the area off the southeastern coast of Hokkaido, Japan, the large earthquakes occurred repeatedly because the Pacific plate is subducting beneath Hokkaido island in the North American plate. After Yamanaka and Kikuchi (2003), the 2003 Tokachi-oki earthquake re-ruptured the same asperity on September 26, 2003, as the 1952 Tokachi-oki earthquake (Mw=8.1). In order to investigate the aftershock activity in the rupture area, we deployed 47 Ocean Bottom Seismometers (OBSs) immediately after the main earthquake. By using the travel time data from the OBS network, the accurate aftershock distribution was obtained [Shinohara et al (2004), Yamada et al (2005)]. In this study, we picked P arrival times of the aftershocks selected carefully as the best data set for a seismic tomographic inversion. And then we estimated 3D P-wave velocity structure by applying the P travel time data to the simultaneous inversion method [Thurber (1983, 1993), Eberhart-Phillips (1986, 1990)]. Although we couldn't image the overall structure of the subducting Pacific plate because of the shallow seismicity, the subducting plate is imaged as velocity anomalies dipping toward northwest. It is suggested from the result of the hypocenters relocated in the consequence of the inversion that the dip angle of the subducting plate increases at around the distance of 100km from the trench axis. It is also suggested that the dip angle is larger at the northeastern part than the southwestern part of the study area. The fault slip distribution of the 2003 Tokachi-oki earthquake seems to be unrelated to the P-wave velocity (Vp) structure obtained here. In the meantime, S-wave velocity (Vs) structure was not obtained because of the ambiguous S-wave forms and the undefined S-wave arrival times due to the surficial unconsolidated sedimentary layers at the stations. Vp/Vs structure in the rupture area is considered to be related to the source process of the large earthquake. In order to obtain Vp/Vs structure, we need to merge the arrival data of the OBSs with those of the land stations to lessen influence of sedimentary layers.

  15. Computer program modifications of Open-file report 82-1065; a comprehensive system for interpreting seismic-refraction and arrival-time data using interactive computer methods

    USGS Publications Warehouse

    Ackermann, Hans D.; Pankratz, Leroy W.; Dansereau, Danny A.

    1983-01-01

    The computer programs published in Open-File Report 82-1065, A comprehensive system for interpreting seismic-refraction arrival-time data using interactive computer methods (Ackermann, Pankratz, and Dansereau, 1982), have been modified to run on a mini-computer. The new version uses approximately 1/10 of the memory of the initial version, is more efficient and gives the same results.

  16. Analysis of the source scanning algorithm with a new P-wave picker

    NASA Astrophysics Data System (ADS)

    Zahradník, J.; Janský, J.; Plicka, V.

    2015-04-01

    We analyze the location of earthquakes in near regional networks using complete seismic records. The method is based on the source scanning algorithm (SSA) of Kao and Shan (2004), but similarly to Grigoli et al. (2013), seismograms are substituted by a P-wave picker trace. The picker traces in a network are repeatedly stacked using grid of trial source positions, and hypocenter is identified with the point providing the best stack (the largest brightness). The first innovation of this paper is a new picker, measuring the ratio of the summed absolute values of seismogram in the right and left part of a moving time window, the RPA/LPA picker. The brightness maps based on this picker are clearer than those based on the STA/LTA picker. The second innovation is a simple theoretical model of the brightness maps. It makes it easy to identify how individual stations contribute to form the brightness spot. It is shown on synthetic tests that the performance of the method depends on focal mechanism, progressively improving from normal to reverse and strike-slip events. The method is successfully applied to four events of different mechanisms and depths, recorded at different ranges of epicentral distance by either broad-band sensors or accelerographs. The events have been located close to previously published epicenters. The brightness maps provide an estimate of the relative uncertainty of the (non-linear) location problem. The uncertainty estimate is also applicable without measured arrival times, "without earthquakes", thus useful when designing or upgrading seismic networks for better location performance.

  17. A Holographic P-wave Superconductor Model

    E-print Network

    Rong-Gen Cai; Li Li; Li-Fang Li

    2013-12-09

    We study a holographic p-wave superconductor model in a four dimensional Einstein-Maxwell-complex vector field theory with a negative cosmological constant. The complex vector field is charged under the Maxwell field. We solve the full coupled equations of motion of the system and find black hole solutions with the vector hair. The vector hairy black hole solutions are dual to a thermal state with the U(1) symmetry as well as the spatial rotational symmetry breaking spontaneously. Depending on two parameters, the mass and charge of the vector field, we find a rich phase structure: zeroth order, first order and second order phase transitions can happen in this model. We also find "retrograde condensation" in which the hairy black hole solution exists only for the temperatures above a critical value with the free energy much larger than the black hole without hair. We construct the phase diagram for this system in terms of the temperature and charge of the vector field.

  18. Finite Frequency P-Wave Tomography for French Polynesian Region

    NASA Astrophysics Data System (ADS)

    Obayashi, M.; Yoshimitsu, J.; Sugioka, H.; Ito, A.; Isse, T.; Shiobara, H.; Suetsugu, D.

    2014-12-01

    The French Polynesian region is characterized by positive topographic anomalies of 700 m, a concentration of hotspot chains. Many seismic tomography results show a broad low-velocity anomaly in the lower mantle continued from the base of the mantle. These observations suggest that a large-scale mantle flow rises from the bottom of the mantle beneath the region. Joint Japanese-French broadband seismological observations were performed from 2001 to 2005 with 10 island stations from the Polynesian PLUME project and 10 broadband ocean bottom seismometers (BBOBSs) from the Polynesian BBOBS project. A P-wave tomography using the data from these projects revealed that large-scale low-velocity anomalies (on the order of 1000 km in diameter) from the bottom of the mantle become smaller-scale low-velocity anomalies (on the order of 100 km in diameter) at the depth of about 1000 km. However the connection of the small-scale low-velocity anomalies to the surface hotspots was not unrevealed because of the poor resolution in the upper mantle. A new P-wave tomography with better resolution in the upper mantle was obtained by adding data from BBOSBSs around Society Islands deployed along the TIARES project during 2009 - 2010 and by taking the finite frequency effect into account for the frequency-depended differential travel times. The frequency-depended differential travel times were measured by multi-band cross correlating P waveforms. The new P-wave tomography shows strong low-velocity anomalies beneath the Society Islands and Pitcairn in the upper mantle although they do not extend to the 660-km discontinuity. This model also shows that small-scale low-velocity anomalies in the uppermost lower mantle. The low-velocity anomalies in the depth range about 550 - 900 km are smaller both in lateral area and amplitude than those in most of the upper mantle and the lower mantle. There is no correlation between velocity patterns in that depth range and those in the upper mantle or in the lower mantle, suggesting that the broad slow anomalies in the lower mantle do not connect to the surface directly.

  19. Tomographic inversion of P-wave velocity and Q structures beneath the Kirishima volcanic complex, Southern Japan, based on finite difference calculations of complex traveltimes

    USGS Publications Warehouse

    Tomatsu, T.; Kumagai, H.; Dawson, P.B.

    2001-01-01

    We estimate the P-wave velocity and attenuation structures beneath the Kirishima volcanic complex, southern Japan, by inverting the complex traveltimes (arrival times and pulse widths) of waveform data obtained during an active seismic experiment conducted in 1994. In this experiment, six 200-250 kg shots were recorded at 163 temporary seismic stations deployed on the volcanic complex. We use first-arrival times for the shots, which were hand-measured interactively. The waveform data are Fourier transformed into the frequency domain and analysed using a new method based on autoregressive modelling of complex decaying oscillations in the frequency domain to determine pulse widths for the first-arrival phases. A non-linear inversion method is used to invert 893 first-arrival times and 325 pulse widths to estimate the velocity and attenuation structures of the volcanic complex. Wavefronts for the inversion are calculated with a finite difference method based on the Eikonal equation, which is well suited to estimating the complex traveltimes for the structures of the Kirishima volcano complex, where large structural heterogeneities are expected. The attenuation structure is derived using ray paths derived from the velocity structure. We obtain 3-D velocity and attenuation structures down to 1.5 and 0.5 km below sea level, respectively. High-velocity pipe-like structures with correspondingly low attenuation are found under the summit craters. These pipe-like structures are interpreted as remnant conduits of solidified magma. No evidence of a shallow magma chamber is visible in the tomographic images.

  20. Stereoscopic study of the kinematic evolution of a coronal mass ejection and its driven shock from the sun to the earth and the prediction of their arrival times

    SciTech Connect

    Hess, Phillip; Zhang, Jie

    2014-09-01

    We present a detailed study of the complete evolution of a coronal mass ejection (CME). We have tracked the evolution of both the ejecta and its shock, and further fit the evolution of the fronts to a simple but physics-based analytical model. This study focuses on the CME initiated on the Sun on 2012 July 12 and arriving at the Earth on 2012 July 14. Shock and ejecta fronts were observed by white light images, as well as in situ by the Advanced Composition Explorer satellite. We find that the propagation of the two fronts is not completely dependent upon one another, but can each be modeled in the heliosphere with a drag model that assumes the dominant force of affecting CME evolution to be the aerodynamic drag force of the ambient solar wind. Results indicate that the CME ejecta front undergoes a more rapid deceleration than the shock front within 50 R {sub ?} and therefore the propagation of the two fronts is not completely coupled in the heliosphere. Using the graduated cylindrical shell model, as well as data from time-elongation stack plots and in situ signatures, we show that the drag model can accurately describe the behavior of each front, but is more effective with the ejecta. We also show that without the in situ data, based on measurements out to 80 R {sub ?} combined with the general values for drag model parameters, the arrival of both the shock and ejecta can be predicted within four hours of arrival.

  1. Impact of patients' arrival time on the care and in-hospital mortality in patients with non-ST-elevation myocardial infarction.

    PubMed

    Kim, Sung Soo; Jeong, Myung Ho; Rhew, Shi Hyun; Jeong, Wook Young; Ahn, Young Keun; Cho, Jeong Gwan; Kim, Young Jo; Cho, Myeong Chan; Kim, Chong Jin

    2014-01-15

    Only a few studies have focused on the clinical characteristics and outcomes of non-ST-segment myocardial infarction (NSTEMI) during off-hours. The purpose of this study was to compare the impact of patients' arrival time on the care of NSTEMI and whether this pattern might affect hospital mortality. This study analyzed 4,736 NSTEMI patients included in the Korea Acute Myocardial Infarction Registry from November 2005 to January 2008. Patients' arrival time was classified into regular hours (weekdays, 9:00 a.m. to 6:00 p.m.) and off-hours (weekdays 18:01 p.m. to 8:59 a.m., weekends, and holidays). A subtotal of 2,225 (46.9%) patients was admitted during off hours, compared with 2,511 (53.1%) patients with regular-hour admission. A higher proportion of patients admitted during off-hours had a higher Killip class, had more frequent cardiopulmonary resuscitation, were less likely to receive percutaneous coronary intervention (PCI) (67.7% vs 72.7%, p <0.001), and had longer door-to-balloon times (28 hours, interquartile range: 11 to 63 vs 23 hours, interquartile range 4 to 67, p <0.001). Although unadjusted hospital mortality was associated with admission during off-hours (4.5% vs 3.3%, p = 0.023), after adjusting for all patients covariates, the difference in mortality was attenuated and was no longer statistically significant (odds ratio 0.94, 95% confidence interval 0.59 to 1.48, p = 0.793). In conclusion, despite receiving fewer PCIs and having substantially longer waiting times to PCI, patients admitted during off-hours may not be at risk for increased in-hospital mortality. If patients are treated within an appropriate reperfusion strategy according to their clinical risk, arrival time may not influence on mortality. PMID:24295548

  2. P-wave and S-wave traveltime residuals in Caledonian and adjacent units of Northern Europe and Greenland

    NASA Astrophysics Data System (ADS)

    Hejrani, Babak; Balling, Niels; Holm Jacobsen, Bo; Kind, Rainer; Tilmann, Frederik; England, Richard; Bom Nielsen, Søren

    2014-05-01

    This work combines P-wave and S-wave travel time residuals from in total 477 temporary and 56 permanent stations deployed across Caledonian and adjacent units in Northern Europe and Greenland (Tor, Gregersen et al. 2002; SVEKALAPKO, Sandoval et al., 2003; CALAS, Medhus et al, 2012a; MAGNUS, Weidle et al. 2010; SCANLIPS south, England & Ebbing 2012; SCANLIPS north, Hejrani et al. 2012; JULS Hejrani et al. 2013; plus permanent stations in the region). We picked data from 2002 to 2012 (1221 events) using a cross correlation technique on all waveforms recorded for each event. In this way we achieve maximum consistency of relative residuals over the whole region (Medhus et al. 2012b). On the European side 18362 P-wave travel time residuals was delivered. In East Greenland 1735 P-wave residuals were recovered at the Central Fjord array (13 stations) and 2294 residuals from the sparse GLISN-array (23 stations). Likewise, we picked a total of 6034 residuals of the SV phase (For the Tor and SVEKALAPKO projects we used data from Amaru et al. 2008). Relative residuals within the region are mainly due to sub-crustal uppermost mantle velocity anomalies. A dominant subvertical boundary was detected by Medhus et al. (2012), running along the Tornquist zone, east of the Oslo Graben and crossing under high topography of the southern Scandes. We delineated this boundary in more detail, tracking it towards the Atlantic margin north of Trondheim. Further north (Scanlips north), a similar subvertical upper mantle boundary seems to be present close to the coast, coinciding with the edge of the stretched crust. The North German Caledonides were probed by the new JULS (JUtland Lower Saxony) profile which closes the gap between Tor and CALAS arrays. Mantle structure found by the Tor project was confirmed, and modelling was extended to the eastern edge of the North Sea. References: Amaru, M. L., Spakman, W., Villaseñor, A., Sandoval, S., Kissling, E., 2008, A new absolute arrival time data set for Europe.Geophysical Journal International, 173, 465-472. England, R. W.; Ebbing, J., 2012, Crustal structure of central Norway and Sweden from integrated modelling of teleseismic receiver functions and the gravity anomaly.GEOPHYSICAL JOURNAL INTERNATIONAL, 191, 1-11. Gregersen S., Voss P., TOR Working Group, 2002. Summary of project TOR: delineation of a stepwise, sharp, deep lithosphere transition across Germany-Denmark-Sweden, Tectonophysics, 360, 61-73. Hejrani, B., Jacobsen, B. H., Balling,N. and England, R. W.. 2012, A seismic tomography study of lithospheric structure under the Norwegian Caledonides.Geophysical Research Abstracts, 14, 4334. Hejrani, B.; Jacobsen, B.H.; Balling, N.;Tilmann, F.; Kind, R., 2013, Upper-mantle velocity structure beneathJutland, Denmark and northern Germany:Preliminary results. Joint Assembly Gothenburg Abstract S401S2.01, Medhus, A. B., Balling, N., Jacobsen, B. H., Weidle, C., England, R. W., Kind, R., Thybo, H., Voss, P. (2012a): Upper-mantle structure beneath the Southern Scandes Mountains and the Northern Tornquist Zone revealed by P-wave traveltime tomography. Geophysical Journal International, 189, 3, 1315-1334. Medhus, Jacobsen, B. H.,A. B., Balling, N., 2012b, Bias Problems in Existing Teleseismic Travel Time Databases: Ignore or Repair? Seismological Research Letters, 83, 1030-1037. Sandoval, S., Kissling, E. &Ansorge, J., 2003.High-resolution body wave tomography beneath the SVEKALAPKO array: I. A priori three-dimensional crustal model and associated traveltime effects on teleseismic wave fronts, Geophys. J. Int., 153, 75-87. Weidle, C., Maupin, V., Ritter, J.,Kværna, T., Schweitzer J., Balling, N.,Thybo, H.,Faleide, J. I.,and,Wenzel, F., 2010, MAGNUS-A Seismological Broadband Experiment to Resolve Crustal and Upper Mantle Structure beneath the Southern Scandes Mountains in Norway. SEISMOLOGICAL RESEARCH LETTERS, 81, 76-84.

  3. Arrival Metering Precision Study

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Mercer, Joey; Homola, Jeffrey; Hunt, Sarah; Gomez, Ashley; Bienert, Nancy; Omar, Faisal; Kraut, Joshua; Brasil, Connie; Wu, Minghong, G.

    2015-01-01

    This paper describes the background, method and results of the Arrival Metering Precision Study (AMPS) conducted in the Airspace Operations Laboratory at NASA Ames Research Center in May 2014. The simulation study measured delivery accuracy, flight efficiency, controller workload, and acceptability of time-based metering operations to a meter fix at the terminal area boundary for different resolution levels of metering delay times displayed to the air traffic controllers and different levels of airspeed information made available to the Time-Based Flow Management (TBFM) system computing the delay. The results show that the resolution of the delay countdown timer (DCT) on the controllers display has a significant impact on the delivery accuracy at the meter fix. Using the 10 seconds rounded and 1 minute rounded DCT resolutions resulted in more accurate delivery than 1 minute truncated and were preferred by the controllers. Using the speeds the controllers entered into the fourth line of the data tag to update the delay computation in TBFM in high and low altitude sectors increased air traffic control efficiency and reduced fuel burn for arriving aircraft during time based metering.

  4. Trends of some high quantiles of average and extremes inter-arrival times and rainfall depths at daily scale for an Italian Sub-Alpine area

    NASA Astrophysics Data System (ADS)

    Ferraris, Stefano; Agnese, Carmelo; Baiamonte, Giorgio; Canone, Davide; Previati, Maurizio; Cat Berro, Daniele; Mercalli, Luca

    2015-04-01

    Modeling of rainfall statistical structure represents an important research area in hydrology, meteorology, atmospheric physics and climatology, because of the several theoretical and practical implications. The statistical inference of the alternation of wet periods (WP) and dry periods (DP) in daily rainfall records can be achieved through the modelling of inter-arrival time-series (IT), defined as the succession of times elapsed from a rainy day and the one immediately preceding it. It has been shown previously that the statistical structure of IT can be well described by the 3-parameter Lerch distribution (Lch). In this work, Lch was successfully applied to IT data belonging to a sub-alpine area (Piemonte and Valle d'Aosta, NW Italy); furthermore the same statistical procedure was applied to daily rainfall records to ITs associated. The analysis has been carried out for 26 daily rainfall long-series (? 90 yr of observations). The main objective of this work was to detect temporal trends of some features describing the statistical structure of both inter-arrival time-series (IT) and associated rainfall depth (H). Each time-series was divided on subsets of five years long and for each of them the estimation of the Lch parameter was performed, so to extend the trend analysis to some high quantiles.

  5. Black Hole Window into p -Wave Dark Matter Annihilation

    NASA Astrophysics Data System (ADS)

    Shelton, Jessie; Shapiro, Stuart L.; Fields, Brian D.

    2015-12-01

    We present a new method to measure or constrain p -wave-suppressed cross sections for dark matter (DM) annihilations inside the steep density spikes induced by supermassive black holes. We demonstrate that the high DM densities, together with the increased velocity dispersion, within such spikes combine to make thermal p -wave annihilation cross sections potentially visible in ? -ray observations of the Galactic center (GC). The resulting DM signal is a bright central point source with emission originating from DM annihilations in the absence of a detectable spatially extended signal from the halo. We define two simple reference theories of DM with a thermal p -wave annihilation cross section and establish new limits on the combined particle and astrophysical parameter space of these models, demonstrating that Fermi Large Area Telescope is currently sensitive to thermal p -wave DM over a wide range of possible scenarios for the DM distribution in the GC.

  6. Black Hole Window into p-Wave Dark Matter Annihilation.

    PubMed

    Shelton, Jessie; Shapiro, Stuart L; Fields, Brian D

    2015-12-01

    We present a new method to measure or constrain p-wave-suppressed cross sections for dark matter (DM) annihilations inside the steep density spikes induced by supermassive black holes. We demonstrate that the high DM densities, together with the increased velocity dispersion, within such spikes combine to make thermal p-wave annihilation cross sections potentially visible in ?-ray observations of the Galactic center (GC). The resulting DM signal is a bright central point source with emission originating from DM annihilations in the absence of a detectable spatially extended signal from the halo. We define two simple reference theories of DM with a thermal p-wave annihilation cross section and establish new limits on the combined particle and astrophysical parameter space of these models, demonstrating that Fermi Large Area Telescope is currently sensitive to thermal p-wave DM over a wide range of possible scenarios for the DM distribution in the GC. PMID:26684108

  7. Comparison of the CME-associated shock arrival times at the earth using the WSA-ENLIL model with three cone models

    NASA Astrophysics Data System (ADS)

    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.

  8. Genetic Determinants of P Wave Duration and PR Segment

    PubMed Central

    Verweij, Niek; Leach, Irene Mateo; 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

    Background The PR interval on the electrocardiogram reflects atrial depolarization and AV nodal delay which can be partially differentiated by P wave duration and PR segment, respectively. GWAS have identified a number of genetic loci for PR interval but it remains to be determined whether this is driven by P wave duration, PR segment or both. Methods and Results We replicated 7 of the 9 known PR interval loci in 16,468 individuals of European ancestry. Four loci were unambiguously associated with PR segment while the others were shared for P wave duration and PR segment. Next, we performed a genome-wide analysis on P wave duration and PR segment separately and identified five novel loci. SNPs in KCND3 (P=8.3×10?11) and FADS2 (P=2.7×10?8) were associated with P wave duration, whereas SNPs near IL17D (P=2.3×10?8), in EFHA1 (P=3.3×10?10) and LRCH1 (P=2.1×10?8) were associated with PR segment. Analysis on DNA elements indicated that genome-wide significant SNPs were enriched at genomic regions suggesting active gene transcription in the human right atrium. Quantitative-PCR showed that genes were significantly higher expressed in the right atrium and AV-node compared to left ventricle (P=5.6×10?6). Conclusions Genetic associations of PR interval appear to be mainly driven by genetic determinants of the PR segment. Some of the PR interval associations are strengthened by a directional consistent effect of genetic determinants of P wave duration. Through genome-wide association we also identified genetic variants specifically associated with P wave duration which might be relevant for cardiac biology. PMID:24850809

  9. Longitudinal development of muons in large air showers studies from the arrival time distributions measured at 900m above sea level

    NASA Technical Reports Server (NTRS)

    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.

  10. Engineered p-wave collisions in ultracold Fermionic systems

    NASA Astrophysics Data System (ADS)

    Aycock, Lauren; Genkina, Dina; Stuhl, Benjamin; Spielman, Ian

    2014-05-01

    This experiment demonstrates the p-wave and higher odd partial waves describing interactions in a spin polarized Fermi gas: critical for engineering utlracold Fermi gases to support Majorana fermions. Here, we describe an experiment which combines known experimental techniques for modifying interactions between atoms in a unique way to artificially engineer p-wave collisions in ultracold Fermionic systems. Using s-wave Feshbach resonances to tune interactions in degenerate Fermi gases have been very fruitful in studying many-body quantum physics; however, p-Wave Feshbach resonances are limited in their usefulness by large inelastic loss rates. In combination with an s-Wave Feshbach resonance, we modify the fermionic interaction by laser-dressing. We already demonstrated that this technique introduces d- and g-wave contributions to the s-wave scattering in degenerate Bose gases.

  11. Supercurrent in a p-wave holographic superconductor

    SciTech Connect

    Zeng Huabi; Sun Weimin; Zong Hongshi

    2011-02-15

    The p-wave and p+ip-wave holographic superconductors with fixed DC supercurrent are studied by introducing a nonvanishing vector potential. We find that close to the critical temperature T{sub c} of zero current, the numerical results of both the p-wave model and the p+ip model are the same as those of Ginzburg-Landau (GL) theory; for example, the critical current is j{sub c}{approx}(T{sub c}-T){sup 3/2} and the phase transition in the presence of a DC current is a first-order transition. Beside the similar results between both models, the p+ip superconductor shows isotropic behavior for the supercurrent, while the p-wave superconductor shows anisotropic behavior for the supercurrent.

  12. Detection of the electrocardiogram P-wave using wavelet analysis

    SciTech Connect

    Anant, K.S.; Rodrigue, G.H. |; Dowla, F.U.

    1994-01-01

    Since wavelet analysis is an effective tool for analyzing transient signals, we studied its feature extraction and representation properties for events in electrocardiogram (EKG) data. Significant features of the EKG include the P-wave, the QRS complex, and the T-wave. For this paper the feature that we chose to focus on was the P-wave. Wavelet analysis was used as a pre-processor for a backpropagation neural network with conjugate gradient learning. The inputs to the neural network were the wavelet transforms of EKGs at a particular scale. The desired output was the location of the P-wave. The results were compared to results obtained without using the wavelet transform as a pre-processor.

  13. Embedded Fiber Optic Sensors for Measuring Transient Detonation/Shock Behavior;Time-of-Arrival Detection and Waveform Determination.

    SciTech Connect

    Chavez, Marcus Alexander; Willis, Michael David; Covert, Timothy T.

    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.

  14. The transient analysis of the queue-length distribution in the batch arrival system with N-policy, multiple vacations and setup times

    NASA Astrophysics Data System (ADS)

    Kempa, Wojciech M.

    2010-10-01

    A batch arrival queueing system of the MX/G/1 type with unlimited queue is considered. After each busy period the server begins a multiple vacation period, consisting of independent single vacations, when the service process is blocked. The server begins successive single vacations as far as at the end of one of them the number of customers waiting in the queue equals at least N. The service of the first customer after the vacation period is preceded by a setup time. The analysis of the queue-size distribution on the first vacation cycle is directed to the analysis of the same characteristic in the corresponding "usual" system with unremovable server on its first busy period. The renewal-theory approach is used to obtain results in the general case. As main result the explicit representation for the LT of queue-size distribution is derived for the original system.

  15. Automated determination of P-wave polarization at the GRSN

    NASA Astrophysics Data System (ADS)

    Cristiano, L.; Meier, T.; Weidle, C.; Krüger, F.

    2012-04-01

    Polarization analysis of P-waves has been applied for identification of seismic phases (Earle, 1999), for earthquake location (Dyer et al., 1999), measurements of seismic anisotropy (Schulte-Pelkum, 2001), and determination of velocity models. In isotropic, lateral homogeneous media, P-wave polarization is confined to the vertical-radial plane; deviations of horizontal polarization direction from the great-circle propagation direction can be due to smooth lateral velocity heterogeneities, dipping discontinuities, and seismic anisotropy. In order to distinguish between these different causes, P-wave polarization parameters have to be determined for a large number of events in different source regions. Here we present the results of the polarization analysis of P-waves recorded at the GRSN for events in the distance range between 5° and 90°. For a consistent and efficient processing of a large data set we developed an automated procedure for the determination of the P-wave incidence angle and backazimuth. Details of the algorithm are described and results are shown as a function of backazimuth and frequency. We select events with a SNR > 2 at various epicentral distances and avoid the contamination of the P-wave with depth phases. The P-wave polarization parameters are calculated in a moving window using eigenvectors and eigenvalues of the covariance matrix of 3 component records (Jurkevics,1988). The length of the moving window is dependent on epicentral distance and the corner frequency of the band pass filter applied prior the computation of covariance matrix. We also estimate a quality factor and an uncertainty for the polarization parameters in terms of ratio between the intermediate and smallest eigenvalues. An automated picking of the P-wave polarization has been developed based on a characteristic function, defined in terms of amplitude, signal to noise ratios, polarization parameters and their comparison with the predicted ones calculated for the IASP91 model (Kennett, 2005). Especially for lower frequencies results between the stations are comparable. For higher frequencies and local events the spatial variation of the parameters is larger. Interestingly, indications for a dependency on frequency are found in certain distance ranges for incidence angles as well as azimuthal deviations. For comparison we apply the f-k analysis (Capon, 1969) to determine the propagation direction.

  16. Point process with last-arrival-time dependent intensity and 1-dimensional incompressible fluid system with evaporation.

    E-print Network

    Hattori, Tetsuya

    system with evaporation. Tetsuya Hattori Laboratory of Mathematics, Faculty of Economics, Keio by unbounded and space-time dependent evaporation rates. We prove unique existence of the solution occurs at y = 1. Each fluid component, say , evaporates with rate w which may vary among different

  17. Global P-wave tomography of mantle plumes and subducting slabs

    NASA Astrophysics Data System (ADS)

    Yamamoto, Y.; Zhao, D.

    2008-12-01

    There are many volcanoes on the Earth which can be generally classified into 3 categories: island arc volcanoes, mid-ocean ridge volcanoes, and hotspot volcanoes. Hotspot volcanoes denote intraplate volcanoes like Hawaii, or anomalously large mid-ocean ridge volcanoes like Iceland. So far many researchers have studied the origin of hotspot volcanoes and have used mantle plume hypothesis to explain them. However, we still have little knowledge about mantle plumes yet. In this study, we determined a new model of whole mantle P-wave tomography to understand the origin of hotspot volcanoes. We used the global tomography method of Zhao (2001, 2004). A 3-D grid net was set up in the mantle, and velocity perturbations at every grid nodes were taken as unknown parameters. The iasp91 velocity model (Kennett and Engdahl, 1991) was taken as the 1-D initial model. We selected 9106 earthquakes from the events occurred in the last forty years from the ISC catalog. About 1.6 million arrival-time data of five-type P phases (P, pP, PP, PcP, and Pdiff) were used to conduct the tomographic inversion. In our previous model (Zhao, 2004), the grid interval in the E-W direction is too small in the polar regions. In this study, in order to remedy this problem, we use a flexible-grid approach to make the lateral grid intervals in the polar regions nearly the same as the other portions of the mantle. As a result, the tomographic images in the polar regions are remarkably improved. Our new tomographic model shows huge low-velocity (low-V) zones in the entire mantle under Tahiti and Lake Victoria, which reflect the Pacific and African superplumes, being consistent with the previous studies. A clear low-V zone is revealed under Mt. Erebus volcano in Antarctica. Other major hotspots also exhibit significant low-V zones in the mantle under their surface locations. Beneath Bering Sea, we found that the Pacific slab is subducting from the Aleutian trench and it is stagnant in the mantle transition zone. In Bering Sea, there are several intraplate volcanoes such as St. Paul island. Given the existence of the stagnant Pacific slab and very low-V mantle wedge above the slab, we think that the origin of the intraplate volcanoes in Bering Sea is most likely related to the deep subduction of the Pacific slab and its stagnancy in the mantle transition zone, similar to the Changbai and Wudalianchi volcanoes in Northeast Asia (Zhao, 2004). Zhao, D. (2001) Earth Planet. Sci. Lett. 192, 251-265. Zhao, D. (2004) Phys. Earth Planet. Inter. 146, 3-34.

  18. P-wave residuals at stations in Nepal - Evidence for a high velocity region beneath the Karakorum

    NASA Technical Reports Server (NTRS)

    Pandey, M. R.; Roecker, Steven W.; Molnar, Peter

    1991-01-01

    P-wave residuals recorded at stations in Nepal from events to the northwest and closer than about 20 deg are consistently earlier than those from other directions by about 2.5 sec. These early arrivals are associated with paths confined to the upper 300 km of the earth and suggest that cold material occupies the uppermost mantle beneath the Karakorum, northwest Himalaya, and western Kunlun. Thus, these data suggest that convective downwelling occurs more vigorously in this region than beneath the rest of the Himalaya, Tibet, and their surroundings.

  19. P-wave velocity structure offshore central Sumatra: implications for compressional and strike-slip faulting

    NASA Astrophysics Data System (ADS)

    Karplus, M.; Henstock, T.; McNeill, L. C.; Vermeesch, P. M. T.; Barton, P. J.

    2014-12-01

    The Sunda subduction zone features significant along-strike structural variability including changes in accretionary prism and forearc morphology. Some of these changes have been linked to changes in megathrust faulting styles, and some have been linked to other thrust and strike-slip fault systems across this obliquely convergent margin (~54-58 mm/yr convergence rate, 40-45 mm/yr subduction rate). We examine these structural changes in detail across central Sumatra, from Siberut to Nias Island, offshore Indonesia. In this area the Investigator Fracture Zone and the Wharton Fossil Ridge, features with significant topography, are being subducted, which may affect sediment thickness variation and margin morphology. We present new seismic refraction P-wave velocity models using marine seismic data collected during Sonne cruise SO198 in 2008. The experiment geometry consisted of 57 ocean bottom seismometers, 23 land seismometers, and over 10,000 air gun shots recorded along ~1750 km of profiles. About 130,000 P-wave first arrival refractions were picked, and the picks were inverted using FAST (First Arrivals Refraction Tomography) 3-D to give a velocity model, best-resolved in the top 25 km. Moho depths, crustal composition, prism geometry, slab dip, and upper and lower plate structures provide insight into the past and present tectonic processes at this plate boundary. We specifically examine the relationships between velocity structure and faulting locations/ styles. These observations have implications for strain-partitioning along the boundary. The Mentawai Fault, located west of the forearc basin in parts of Central Sumatra, has been interpreted variably as a backthrust, strike-slip, and normal fault. We integrate existing data to evaluate these hypotheses. Regional megathrust earthquake ruptures indicate plate boundary segmentation in our study area. The offshore forearc west of Siberut is almost aseismic, reflecting the locked state of the plate interface, which last ruptured in 1797. The weakly-coupled Batu segment experiences sporadic clusters of events near the forearc slope break. The Nias segment in the north ruptured in the 2005 M8.7 earthquake. We compare P-wave velocity structure to the earthquake data to examine potential links between lithospheric structure and seismogenesis.

  20. Basement configuration of on-land Kutch basin from seismic refraction studies and modeling of first arrival travel time skips

    NASA Astrophysics Data System (ADS)

    Prasad, B. Rajendra; Venkateswarlu, N.; Prasad, A. S. S. S. R. S.; Murthy, A. S. N.; Sateesh, T.

    2010-10-01

    The Kutch basin is one of the three (Narmada, Cambay and Kutch) major marginal rift basins that are close to each other in mid-western part of the Indian subcontinent. The seismic refraction and wide-angle reflection data were acquired and a first order velocity structure of the Kutch sedimentary basin along Jakhau-Mandvi, Mandvi-Mundra, Mundra-Adesar and Hamirpur-Halvad profiles is derived. The travel time skip phenomenon has been noticed in the travel time plots and record sections indicating presence of low velocity sediments. Derived two-dimensional velocity-depth models revealed a Mesozoic sedimentary sequence sandwiched between Trap and Limestone layers, in some of the profiles. Two thick low velocity layers (that corresponds early to late Mesozoic era) have been identified. These are dipping towards Mandvi along Jakhau-Mandvi profile. The early Mesozoic layer that is thinning towards southeast is completely missing in Mandvi-Mundra profile. It is also noticed that the early Mesozoic Bhuj formation exists in the northern parts of the Mundra-Adesar and Hamirpur-Halvad profiles, where it directly overlies the granitic basement. The derived velocity-depth model suggests that the basement is about 3 km deep near Jakhau and reaches a depth of about 6 km near Mandvi. The layered structure may correspond to the Tertiary, Trap, Late Mesozoic sediments and Mesozoic limestone. The velocity-depth model obtained in Kutch is very similar to earlier derived model for Jamnagar and Dwarka sub-basins of northwestern Saurashtra peninsula suggesting probable continuity/linkage between southern on-land Kutch and, across the Gulf of Kutch to Saurashtra peninunsula. We also conclude that the evolution of Kutch basin, as a peri-cratonic rift basin, is essentially controlled by the four (F1-F4) faults inferred from obvious abrupt changes in layer thickness/velocity along the seismic refraction profiles.

  1. Changes in P-wave velocity with different full waveform sonic transmitter centre frequency

    NASA Astrophysics Data System (ADS)

    Almalki, Majed; Harris, Brett; Dupuis, J. Christian

    2015-05-01

    Full waveform sonic logging, with the transmitter set at different centre frequencies, often provides different compressional wave velocities over the same interval. There may be several reasons why these velocity differences are recovered where the source has different frequency content. Examples include: intrinsic dispersion, scattering dispersion, geometric dispersion, processing artefacts and acquisition artefacts. We acquired and analysed multifrequency monopole full waveform sonic logging data from the cored drill hole intersecting a high-permeability sandy aquifer in the Northern Gnangara Mound, Perth Basin, Western Australia. A key interval of the shallow, sand-dominated Yarragadee Formation was selected and logged four times with transmitter centre frequencies set to 1, 3, 5 and 15 kHz. We compute apparent velocity dispersion as the percentage velocity differences in the P-wave velocity recovered from full waveform sonic logs completed at different dominant transmitter centre frequencies. We find that high-permeability sediments could be placed into broad groups: cross-bedded and non-cross-bedded sandstones. We find a distinctly different relationship between apparent P-wave velocity dispersion and permeability for cross-bedded and non-cross-bedded sandstones. Cross plots for the two sediment types show a general trend of increasing apparent dispersion with increasing permeability. Grouping the sandstone layers based on sediment type, as observed from core samples, illustrates different but positive correlation between the apparent P-wave velocity dispersion and permeability in these shallow, weakly-consolidated sandstones. The cross-bedded sandstone, for its part, has a wider range of permeability than the non-cross-bedded sandstone but a smaller range of apparent P-wave velocity dispersion. Given these results, our hypothesis is that while permeability plays a role, other factors such as geometric dispersion or scattering dispersion likely contribute the net value of P-wave dispersion recovered between any two receivers. Finally the results from these experiments have shown that there exists at least a weak empirical relationship between P-wave velocity dispersion and hydraulic permeability at the field site.

  2. Mantle Attenuation Estimated from Regional and Teleseismic P-waves of Deep Earthquakes and Surface Explosions

    NASA Astrophysics Data System (ADS)

    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 < M w < 5.5) in the Jilin-Heilongjiang, China region that borders with Russia and North Korea. These earthquakes are 200-300 km from the NKTS, within 200 km of the Global Seismic Network seismic station in Mudanjiang, China (MDJ) and the International Monitoring System primary arrays at Ussuriysk, Russia (USRK) and Wonju, Republic of Korea (KSRS). With the deep earthquakes, we split the t*(total) ray path into two segments: a t*(u), that represents the attenuation of the up-going ray from the deep hypocenters to the local-regional receivers, and t*(d), that represents the attenuation along the down-going ray to teleseismic receivers. The sum of t*(u) and t*(d) should be equal to t*(total), because they both share coincident ray paths. We estimated the upper-mantle attenuation t*(u) of 0.1 s at stations MDJ, USRK, and KSRS from individual and stacks of normalized P-wave spectra. We then estimated the average lower-mantle attenuation t*(d) of 0.4 s using stacked teleseismic P-wave spectra. We finally estimated a network average t*(total) of 0.5 s from the stacked teleseismic P-wave spectra from the 2009 nuclear 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 ?2 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.

  3. High frequency P wave attenuation and degradation of detection capability by large earthquakes

    NASA Astrophysics Data System (ADS)

    Bache, T. C.; Bratt, S. R.

    1985-09-01

    This report describes two distinct seismological studies. The first is High Frequency P Wave Attenuation Along Five Teleseismic Paths from Central Asia. P Wave spectra from E. Kazakhstan explosions recorded at five arrays are computed for all five paths using an absorption band model. The Q exhibits strong frequency dependence in the band from 0.5 to 3 Hz, and is nearly the same for all five paths. The second study is, An Investigation of the Degradation of Teleseismic Detection Capability Caused by Large Earthquakes. A ten year global seismicity bulletin is searched to determine the extent to which large earthquakes inhibit the detection of small earthquakes occurring a short time thereafter. Significant degradation of the detection capability of the 115 station global network contributing to the bulletin is seen for periods up to an hour for earthquakes of M sub b 5.8 and larger.

  4. Acoustic Source Localization via Time Difference of Arrival Estimation for Distributed Sensor Networks Using Tera-Scale Optical Core Devices

    DOE PAGESBeta

    Imam, Neena; Barhen, Jacob

    2009-01-01

    For real-time acoustic source localization applications, one of the primary challenges is the considerable growth in computational complexity associated with the emergence of ever larger, active or passive, distributed sensor networks. These sensors rely heavily on battery-operated system components to achieve highly functional automation in signal and information processing. In order to keep communication requirements minimal, it is desirable to perform as much processing on the receiver platforms as possible. However, the complexity of the calculations needed to achieve accurate source localization increases dramatically with the size of sensor arrays, resulting in substantial growth of computational requirements that cannot bemore »readily met with standard hardware. One option to meet this challenge builds upon the emergence of digital optical-core devices. The objective of this work was to explore the implementation of key building block algorithms used in underwater source localization on the optical-core digital processing platform recently introduced by Lenslet Inc. This demonstration of considerably faster signal processing capability should be of substantial significance to the design and innovation of future generations of distributed sensor networks.« less

  5. The Patient Arrival Process in Hospitals

    PubMed Central

    Swartzman, Gordon

    1970-01-01

    The arrival process for emergency patients, impatients, and scheduled and unscheduled outpatients is closely studied by time-series analysis. The hourly variation in weekday arrival rates is examined and a model describing the processes with a considerable degree of predictive accuracy is developed. The model is tested by comparing predicted values with data from a follow-up survey. PMID:5508522

  6. Ratios in Higher Order Statistics (RHOS) values of Seismograms for Improved Automatic P-Phase Arrival Detection

    E-print Network

    Dugda, Mulugeta

    2010-01-01

    In this paper we present two new procedures for automatic detection and picking of P-wave arrivals. The first involves the application of kurtosis and skewness on the vector magnitude of three component seismograms. Customarily, P-wave arrival detection techniques use vertical component seismogram which is appropriate only for teleseismic events. The inherent weakness of those methods stems from the fact that the energy from P-wave is distributed among horizontal and vertical recording channels. Our procedure, however, uses the vector magnitude which accommodates all components. The results show that this procedure would be useful for detecting/picking of P-arrivals from local and regional earthquakes and man-made explosions. The second procedure introduces a new method called "Ratios in Higher Order Statistics (RHOS)." Unlike commonly used techniques that involve derivatives, this technique employs ratios of adjacent kurtosis and skewness values to improve the accuracy of the detection of the P onset. RHOS c...

  7. Crust and upper mantle P wave velocity structure beneath Valles caldera, New Mexico: Results from the Jemez teleseismic tomography experiment

    SciTech Connect

    Steck, Lee K.; Fehler, Michael C.; Roberts, Peter M.; Baldridge, W. Scott; Stafford, Darrik G.; Lutter, William J.; Sessions, Robert

    1998-10-01

    New results are presented from the teleseismic component of the Jemez Tomography Experiment conducted across Valles caldera in northern New Mexico. We invert 4872 relative {ital P} wave arrival times recorded on 50 portable stations to determine velocity structure to depths of 40 km. The three principle features of our model for Valles caldera are: (1) near-surface low velocities of {minus}17{percent} beneath the Toledo embayment and the Valle Grande, (2) midcrustal low velocities of {minus}23{percent} in an ellipsoidal volume underneath the northwest quadrant of the caldera, and (3) a broad zone of low velocities ({minus}15{percent}) in the lower crust or upper mantle. Crust shallower than 20 km is generally fast to the northwest of the caldera and slow to the southeast. Near-surface low velocities are interpreted as thick deposits of Bandelier tuff and postcaldera volcaniclastic rocks. Lateral variation in the thickness of these deposits supports increased caldera collapse to the southeast, beneath the Valle Grande. We interpret the midcrustal low-velocity zone to contain a minimum melt fraction of 10{percent}. While we cannot rule out the possibility that this zone is the remnant 1.2 Ma Bandelier magma chamber, the eruption history and geochemistry of the volcanic rocks erupted in Valles caldera following the Bandelier tuff make it more likely that magma results from a new pulse of intrusion, indicating that melt flux into the upper crust beneath Valles caldera continues. The low-velocity zone near the crust-mantle boundary is consistent with either partial melt in the lower crust or mafic rocks without partial melt in the upper mantle. In either case, this low-velocity anomaly indicates that underplating by mantle-derived melts has occurred. {copyright} 1998 American Geophysical Union

  8. Crustal structure beneath Long Valley caldera from modeling of teleseismic P wave polarizations and Ps converted waves

    SciTech Connect

    Steck, L.K.; Prothero, W.A. Jr.

    1994-04-10

    In this study, the authors present new constraints on the nature of the low-velocity zone beneath Long Valley caldera, based on the measured propagation directions of teleseismic P waves and on modeling of P to S converted waves. The low-velocity body is a large asymmetrical volume which deepens to the east, extending from depths of 7 to 30 km. It contains lower velocities than originally proposed by earlier teleseismic studies. In particular, there is a tabular feature between 7 and 11 km depth that has a reduction in velocity of about 30%. These low velocities imply a much greater percentage of melt in the crust beneath Long Valley caldera than previously estimated. Array analysis of large delayed arrivals identifies them to be Ps converted waves from the shoulders and roof of this tabular zone. These conversions bound the depth to the magma chamber roof to be within about 10 km of the surface. These results are consistent with elements from several other studies, and the authors present an integrated and improved model of crustal structure at Long Valley. The concordance of the deeper low-velocity zones with regional structural trends implies that the shallow low-velocity feature is a cupola on top of an asymmetric diapiric ridge rising up from the migmatized lower crust of the Basin and Range. The authors present two contrasting interpretations of the geometry of low-velocity zones in the crust: one implies a time-invariant magma chamber and conduit system for Long Valley caldera, the other implies an evolution of that system from a simple vertical regime to its current asymmetrical geometry. 37 refs., 19 figs., 1 tab.

  9. Frequency and distance changes in the apparent P-wave radiation pattern: effects of seismic wave scattering in the crust inferred from dense seismic observations and numerical simulations

    NASA Astrophysics Data System (ADS)

    Kobayashi, Manabu; Takemura, Shunsuke; Yoshimoto, Kazuo

    2015-09-01

    Frequency and distance changes in the apparent P-wave radiation pattern (0.75-12 Hz) are investigated using velocity seismograms of shallow strike-slip earthquakes occurring in Chugoku region, southwestern Japan. Data from a dense seismic monitoring network revealed that the four-lobe apparent P-wave radiation pattern was gradually distorted with increasing frequency and propagation distance. Observed features suggest that seismic wave scattering due to small-scale velocity heterogeneity in the crust may be a major cause of this distortion. The effects of seismic wave scattering on apparent P-wave radiation pattern were investigated via 3-D finite difference simulation of seismic wave propagation. Our simulations demonstrated that the scattering of seismic waves modified the apparent P-wave radiation pattern from the original four-lobe shape, and that the small-scale velocity heterogeneity, characterized by the von Kármán-type power spectral density function with correlation distance of 1 km, root-mean-square value of 0.03 and decay rate parameter of 0.5, might be adequate for modelling crustal heterogeneity in the target region. It was also found that the scattering attenuation of P wave expected from this heterogeneity is significantly smaller than the apparent P-wave attenuation and S-wave scattering attenuation reported by Multiple Lapse Time Window Analysis of previous studies in Japan. These results might imply that scattering attenuation is not the dominant mechanism of P-wave attenuation in the crust of Chugoku region.

  10. Estimating Seismic Moment From Broadband P-Waves for Tsunami Warnings.

    NASA Astrophysics Data System (ADS)

    Hirshorn, B. F.

    2006-12-01

    The Richard H. Hagemeyer Pacific Tsunami Warning Center (PTWC), located in Ewa Beach, Oahu, Hawaii, is responsible for issuing local, regional, and distant tsunami warnings to Hawaii, and for issuing regional and distant tsunami warnings to the rest of the Pacific Basin, exclusive of the US West Coast. The PTWC must provide these tsunami warnings as soon as technologically possible, based entirely on estimates of a potentially tsunamigenic earthquake's source parameters. We calculate the broadband P-wave moment magnitude, Mwp, from the P or pP wave velocity seismograms [Tsuboi et al., 1995, 1999]. This method appears to work well for regional and teleseismic events [ Tsuboi et al (1999], Whitmore et al (2002), Hirshorn et al (2004) ]. Following Tsuboi, [1995], we consider the displacement record of the P-wave portion of the broadband seismograms as an approximate source time function and integrate this record to obtain the moment rate function, Mo(t), and the moment magnitude [Hanks and Kanamori, 1972] as a function of time, Mw(t). We present results for Mwp for local, regional, and teleseismic broad band recordings for earthquakes in the Mw 5 to 9.3 range. As large Hawaii events are rare, we tested this local case using other Pacific events in the magnitude 5.0 to 7.5 range recorded by nearby stations. Signals were excluded, however, if the epicentral distance was so small (generally less than 1 degree) that there was contamination by the S-wave too closely following the P-waves. Scatter plots of Mwp against the Harvard Mw for these events shows that Mwp does predict Mw well from seismograms recorded at local, regional, and teleseismic distances. For some complex earthquakes, eg. the Mw 8.4(HRV) Peru earthquake of June 21, 2001, Mwp underestimates Mw if the first moment release is not the largest. Our estimates of Mwp for the Mw 9.3 Summatra-Andaman Island's earthquake of December 26, 2004 and for the Mw 8.7 (HRV) Summatra event of March 28, 2005, were Mwp 8.1, Mwp 8.7 respectively, from p-waves recorded at 15 - 90 degrees from each hypocenter.

  11. Electrocardiographic P-wave characteristics in patients with psoriasis vulgaris

    PubMed Central

    Erdogan, Ercan; Tasal, Abdurrrahman; Vatankulu, Mehmet Akif; Kul, Seref; Sevgili, Emrah; Ertas, Gokhan; Dizman, Didem; Onsun, Nahide; Uysal, Omer

    2013-01-01

    Purpose Psoriasis vulgaris is one of the most common skin disorders. Patients with psoriasis carry an excessive risk of atrial fibrillation (AF). The differences between the maximum (Pmax) and the minimum (Pmin) P-wave duration on ECG are defined as P-wave dispersion (PWD). Prolongation of PWD is an independent risk factor for the development of AF. The aim of this the study was to investigate P-wave duration and PWD in patients with psoriasis. Methods Sixty-one adult patients with psoriasis vulgaris (group 1) and 58 age and sex-matched healthy individuals (group 2) were included in this study. ECG recordings were obtained, and the P-wave variables were calculated. Results were reported as mean ± standard deviation and percentages. Continuous variables were analysed using Student's t test. A value of P < 0.05 was considered statistically signi?cant. Results Pmax and PWD were significantly higher in group 1 than in group 2 (108.8 ± 21.3 ms versus 93.3 ± 13.0 ms, P < 0.001; 67.4 ± 22.9 ms versus 45.0 ± 19.6 ms, P < 0.001, respectively). Also, Pmin was significantly lower in group 1 (41.3 ± 12.3 ms versus 48.3 ± 14.3 ms, P = 0.04). The psoriasis disease activity score and hsCRP correlated with PWD (P < 0.01). Conclusions Atrial conduction of sinus impulses was impaired in patients with psoriasis vulgaris. It was more prominent in patients with severe disease. Physicians caring for patients with psoriasis vulgaris should screen them for AF development. PMID:23153368

  12. p-wave optical Feshbach resonances in {sup 171}Yb

    SciTech Connect

    Goyal, Krittika; Deutsch, Ivan; Reichenbach, Iris

    2010-12-15

    We study the use of an optical Feshbach resonance to modify the p-wave interaction between ultracold polarized {sup 171}Yb spin-1/2 fermions. A laser exciting two colliding atoms to the {sup 1}S{sub 0}+{sup 3}P{sub 1} channel can be detuned near a purely-long-range excited molecular bound state. Such an exotic molecule has an inner turning point far from the chemical binding region, and thus, three-body recombination in the Feshbach resonance will be highly suppressed in contrast to that typically seen in a ground-state p-wave magnetic Feshbach resonance. We calculate the excited molecular bound-state spectrum using a multichannel integration of the Schroedinger equation, including an external perturbation by a magnetic field. From the multichannel wave functions, we calculate the Feshbach resonance properties, including the modification of the elastic p-wave scattering volume and inelastic spontaneous scattering rate. The use of magnetic fields and selection rules for polarized light yields a highly controllable system. We apply this control to propose a toy model for three-color superfluidity in an optical lattice for spin-polarized {sup 171}Yb, where the three colors correspond to the three spatial orbitals of the first excited p band. We calculate the conditions under which tunneling and on-site interactions are comparable, at which point quantum critical behavior is possible.

  13. Revealing the architecture of the upper boundary of the Philippine Sea Plate beneath the northern tip of the Izu-Tanzawa Collision Zone, Central Japan, using later-phase of P waves

    NASA Astrophysics Data System (ADS)

    Shuri, Y.; Tsumura, N.

    2010-12-01

    In Izu-Tanzawa Collision Zone (ITCZ), Izu arc collides with Japan arc due to subduction of the Philippine Sea plate (PHP). Recent studies by Kikuchi (2008) and Arai et al. (2009) have revealed that the upper boundary of PHP has a complex geometry in this area. High seismicity near the top boundary of PHP is reported in the front (northern) edge of the ITCZ, which is the transition zone from collision to subduction of PHP, whereas an aseismic zone is located on the western part of the high seismicity region. This spatial variation of seismicity is probably related to the shape of PHP caused by the difference between collisional vs. subductive movements. To better correlate the spatial distribution of seismicity and the plate configuration, we attempt to find a discontinuous surface near the upper boundary of PHP using later phases of P waves. We used seismic-waveform data from the website of Hi-net seismic network. In the high seismicity region, clear later phases of P waves (X phases) are observed in vertical component seismograms recorded at the stations above the high seismicity region. The X phases arrive 0.5s to 2.0s after P arrivals. Time difference between P and X arrivals (X-P times) increases with distances between the plate boundary and the hypocenters. Similarly, X-P times increase as the distances from the northwestern edge of the high seismicity region to the hypocenters increase. These observations suggest two possibilities for the origin of the X phases: (1) a converted wave at the upper boundary of PHP or (2) a reflected wave from the edge of the high seismicity region. First we searched a suitable plane for which calculated X-P times can match the observed X-P times, by assuming the X phases are converted waves. We found that two converted planes located at different depths would best explain all observed X-P times simultaneously; the depth of the estimated plane in the western side of the high seismicity zone is deeper than that of the eastern side. Next, we determined reflection points for which the observed X-P times can fit: estimated reflection points were concentrated in the northwestern edge of the high seismicity region. In either case, generation points of X phases are located near the top boundary of PHP and it would be expected that the detailed structure near the top boundary of the PHP could be clarified using these later phases. Acknowledgement: We thank the National Research Institute for Earth Science and Disaster Prevention of Japan for providing the Hi-net data.

  14. Memory of the Lake Rotorua catchment - time lag of the water in the catchment and delayed arrival of contaminants from past land use activities

    NASA Astrophysics Data System (ADS)

    Morgenstern, Uwe; Daughney, Christopher J.; Stewart, Michael K.; McDonnell, Jeffrey J.

    2013-04-01

    The transit time distribution of streamflow is a fundamental descriptor of the flowpaths of water through a catchment and the storage of water within it, controlling its response to landuse change, pollution, ecological degradation, and climate change. Significant time lags (catchment memory) in the responses of streams to these stressors and their amelioration or restoration have been observed. Lag time can be quantified via water transit time of the catchment discharge. Mean transit times can be in the order of years and decades (Stewart et al 2012, Morgenstern et al., 2010). If the water passes through large groundwater reservoirs, it is difficult to quantify and predict the lag time. A pulse shaped tracer that moves with the water can allow quantification of the mean transit time. Environmental tritium is the ideal tracer of the water cycle. Tritium is part of the water molecule, is not affected by chemical reactions in the aquifer, and the bomb tritium from the atmospheric nuclear weapons testing represents a pulse shaped tracer input that allows for very accurate measurement of the age distribution parameters of the water in the catchment discharge. Tritium time series data from all catchment discharges (streams and springs) into Lake Rotorua, New Zealand, allow for accurate determination of the age distribution parameters. The Lake Rotorua catchment tritium data from streams and springs are unique, with high-quality tritium data available over more than four decades, encompassing the time when the bomb-tritium moved through the groundwater system, and from a very high number of streams and springs. Together with the well-defined tritium input into the Rotorua catchment, this data set allows for the best understanding of the water dynamics through a large scale catchment, including validation of complicated water mixing models. Mean transit times of the main streams into the lake range between 27 and 170 years. With such old water discharging into the lake, most of the water inflows into the lake are not yet fully representing the nitrate loading in their sub-catchments from current land use practises. These water inflows are still 'diluted' by pristine old water, but over time, the full amount of nitrate load will arrive at the lake. With the age distribution parameters, it is possible to predict the increase in nitrate load to the lake via the groundwater discharges. All sub-catchments have different mean transit times. The mean transit times are not necessarily correlated with observable hydrogeologic properties like hydraulic conductivity and catchment size. Without such age tracer data, it is therefore difficult to predict mean transit times (lag times, memory) of water transfer through catchments. References: Stewart, M.K., Morgenstern, U., McDonnell, J.J., Pfister, L. (2012). The 'hidden streamflow' challenge in catchment hydrology: A call to action for streamwater transit time analysis. Hydrol. Process. 26,2061-2066, Invited commentary. DOI: 10.1002/hyp.9262 Morgenstern, U., Stewart, M.K., and Stenger, R. (2010) Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow, Hydrol. Earth Syst. Sci, 14, 2289-2301

  15. Scattered P'P' waves observed at short distances

    USGS Publications Warehouse

    Earle, Paul; 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 (?t, ?r) 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.

  16. [Approach to recognition of ECG P waves based on approximating functions].

    PubMed

    Yang, Z; Li, L; Ling, J

    1998-06-01

    A new method of recognizing ECG P waves based on approximating function is presented in this paper. The result of experiment demonstrates that the method based on the second order approximating functions to recognize P waves in useful and easy to do. The rate of correctness for recognizing P waves is higher than 99% according to MIT/BIH ECG Datebase. PMID:12548896

  17. Majorana zero modes in the hopping-modulated one-dimensional p-wave superconducting model

    PubMed Central

    Gao, Yi; Zhou, Tao; Huang, Huaixiang; Huang, Ran

    2015-01-01

    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. PMID:26586205

  18. Majorana zero modes in the hopping-modulated one-dimensional p-wave superconducting model.

    PubMed

    Gao, Yi; Zhou, Tao; Huang, Huaixiang; Huang, Ran

    2015-01-01

    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. PMID:26586205

  19. Impact of Phase Transitions on P Wave Velocities

    SciTech Connect

    D Weidner; L Li

    2011-12-31

    In regions where a high pressure phase is in equilibrium with a low pressure phase, the bulk modulus defined by the P-V relationship is greatly reduced. Here we evaluate the effect of such transitions on the P wave velocity. A model, where cation diffusion is the rate limiting factor, is used to project laboratory data to the conditions of a seismic wave propagating in the two-phase region. We demonstrate that for the minimum expected effect there is a significant reduction of the seismic velocity, as large as 10% over a narrow depth range.

  20. Hydrodynamic modes of a holographic p-wave superfluid

    NASA Astrophysics Data System (ADS)

    Arias, Raúl E.; Landea, Ignacio Salazar

    2014-11-01

    In this work we analyze the hydrodynamics of a p- wave superfluid on its strongly coupled regime by considering its holographic description. We obtain the poles of the retarded Green function through the computation of the quasi-normal modes of the dual AdS black hole background finding diffusive, pseudo-diffusive and sound modes. For the sound modes we compute the speed of sound and its attenuation as function of the temperature. For the diffusive and pseudo-diffusive modes we find that they acquire a non-zero real part at certain finite momentum.

  1. Impact of Phase Transitions on P Wave Velocities

    SciTech Connect

    Weidner, D.; Li, L

    2010-01-01

    In regions where a high pressure phase is in equilibrium with a low pressure phase, the bulk modulus defined by the P-V relationship is greatly reduced. Here we evaluate the effect of such transitions on the P wave velocity. A model, where cation diffusion is the rate limiting factor, is used to project laboratory data to the conditions of a seismic wave propagating in the two-phase region. We demonstrate that for the minimum expected effect there is a significant reduction of the seismic velocity, as large as 10% over a narrow depth range.

  2. p-Wave Cold Collisions in an Optical Lattice Clock

    SciTech Connect

    Lemke, N. D.; Sherman, J. A.; Oates, C. W.; Ludlow, A. D.; Stecher, J. von; Rey, A. M.

    2011-09-02

    We study ultracold collisions in fermionic ytterbium by precisely measuring the energy shifts they impart on the atoms' internal clock states. Exploiting Fermi statistics, we uncover p-wave collisions, in both weakly and strongly interacting regimes. With the higher density afforded by two-dimensional lattice confinement, we demonstrate that strong interactions can lead to a novel suppression of this collision shift. In addition to reducing the systematic errors of lattice clocks, this work has application to quantum information and quantum simulation with alkaline-earth atoms.

  3. Association of hematological variables and castration status at the time of arrival at a research facility with the risk of bovine respiratory disease in beef calves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to analyze the association between hematological parameters (CBC) and gender at stocker receiving facility arrival and the risk of subsequent clinical bovine respiratory disease (BRD) diagnosis, and (2) to determine and evaluate the accuracy of CBC parameter threshold...

  4. Derivation of site-specific relationships between hydraulic parameters and p-wave velocities based on hydraulic and seismic tomography

    SciTech Connect

    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.

  5. First high resolution P wave velocity structure beneath Tenerife Island, (Canary Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Garcia-Yeguas, Araceli; Ivan, Koulakov; Ibañez Jesus, M.; Valenti, Sallarès.

    2010-05-01

    3D velocity structure distribution has been imaged for first time using high resolution traveltime seismic tomography of the active volcano of Tenerife Island (Canary Islands, Spain). It is located in the Atlantic Ocean. In this island is situated the Teide stratovolcano (3718 m high) that is part of the Cañadas-Teide-Pico Viejo volcanic complex. Las Cañadas is a caldera system more than 20 kilometers wide where at least four distinct caldera processes have been identified. Evidence for many explosive eruptions in the volcanic complex has been found; the last noticeable explosive eruption (sub-plinean) occurred at Montaña Blanca around 2000 years ago. During the last 300 years, six effusive eruptions have been reported, the last of which took place at Chinyero Volcano on 18 November 1909. In January 2007, a seismic active experiment was carried out as part of the TOM-TEIDEVS project. About 6850 air gun shots were fired on the sea and recorded on a dense local seismic land network consisting of 150 independent (three component) seismic stations. The good quality of the recorded data allowed identifying P-wave arrivals up to offsets of 30-40 km obtaining more than 63000 traveltimes used in the tomographic inversion. The images have been obtained using ATOM-3D code (Koulakov, 2009). This code uses ray bending algorithms in the ray tracing for the forward modelling and in the inversion step it uses gradient methods. The velocity models show a very heterogeneous upper crust that is usual in similar volcanic environment. The tomographic images points out the no-existence of a magmatic chamber near to the surface and below Pico Teide. The ancient Las Cañadas caldera borders are clearly imaged featuring relatively high seismic velocity. Moreover, we have found a big low velocity anomaly in the northwest dorsal of the island. The last eruption took place in 1909 in this area. Furthermore, in the southeast another low velocity anomaly has been imaged. Several resolution and accuracy tests were carried out to quantify the reliability of the final velocity models. Checkerboard tests show that the well-resolved are located up to 6-8 km depth. Also we carried out synthetic tests in which we successfully reproduce single anomalies observed in the velocity models. Especially we have study carefully the low velocity anomalies found in the NW and SE, which have been recovered successfully. The jack-knife technique have been used and our results are stable if we remove the 50% of the data for different stations, but if we reject all the data for some stations, the velocity models can change. These tests assure the uniqueness of the first 3D velocity model that characterizes the internal structure of the Tenerife Island. As main conclusions of our work we can remark: a) This is the first 3-D velocity image of the area; b) we have observed low velocity anomalies near to surface that could be associated to the presence of magma, water reservoirs and volcanic landslides; c) high velocity anomalies could be related to ancient volcanic episodes or basement structures; d) our results could help to resolve many questions relate to the evolution of the volcanic system, as the presence or not of big landslides, calderic explosions or others; e) this image is a very important tool to improve the knowledge of the volcanic hazard, and therefore volcanic risk. We would like to highlight the importance of take into account the risk of eruption in other areas besides Pico Teide-Las Cañadas system.

  6. Relationship between macro-fracture density, P-wave velocity, and permeability of coal

    NASA Astrophysics Data System (ADS)

    Wang, Haichao; Pan, Jienan; Wang, Sen; Zhu, Haitao

    2015-06-01

    This study was undertaken to determine the quantitative relationship between macro-fracture density, P-wave velocity, porosity and permeability of different coal rank samples from mining areas in North China. The coal sample permeability shows an exponential growth with increasing fracture density. The relation between P-wave velocity and porosity is power function and P-wave velocity decreases with the increasing porosity. P-wave velocity linearly or nonlinearly decreases with the increase of fracture density in the selected coal samples (0.73-3.59% Ro). However, the overall trend is that P-wave velocity decreases with an increase in macro-fracture density. The permeability of coal samples linearly decreases with the increase of P-wave velocity. The quantitative relationship between P-wave velocity and permeability could provide reference for the further study of permeability predicting.

  7. Skyrmion Flux Lattices in p,-wave Superconductors

    NASA Astrophysics Data System (ADS)

    Li, Qi; Toner, John; Belitz, Dietrich

    2007-03-01

    In p,-wave superconductors, topological excitations known as skyrmions are allowed, in addition to the usual vortices. In strongly type-II materials in an external magnetic field, a skyrmion flux lattice is expected to be energetically favored compared to a vortex flux lattice [1]. We analytically calculate the energy, magnetization curves (B(H)), and elasticity of skyrmion flux lattices in p,-wave superconductors near the lower critical field Hc1, and use these results with the Lindemann criterion to predict their melting curve [2]. In striking contrast to vortex flux lattices, which always melt at an external field H > Hc1, skyrmion flux lattices never melt near Hc1. This provides a simple and unambiguous test for the presence of skyrmions. In addition, the internal magnetic field distributions (which are measurable by muon spin rotation techniques [3]) of skyrmion and vortex lattices are very different. [1] A. Knigavko, B. Rosenstein, and Y.F. Chen, Phys. Rev. B 60, 550 (1999). [2] Qi Li, John Toner, and D. Belitz, cond-mat/0607391 [3] J.E. Sonier, J. Phys. Cond. Matt. 16, S4499 (2004)

  8. A New P-wave Frequency Dependent Magnitude Estimation Technique

    NASA Astrophysics Data System (ADS)

    Veith, K. F.; Rivers, W.; Wagner, R.

    2005-12-01

    A new procedure for estimating Mb is suggested which is analogous to the new procedure being proposed by Russell and Bonner (2005) for the estimation of surface wave magnitudes. The measurement process involves the use of narrow pass band Butterworth filters on broad band station data that isolate the amplitude of the P waves at each particular frequency. The amplitude-period data are then used to estimate magnitudes with corrections for both the filtering process and frequency dependent attenuation. The magnitudes generally vary smoothly with frequency and the maximum value is selected for each station's Mb. The technique offers a number of advantages over tradition Mb measurement procedures. These include an inherently increasing window length with increasing period. This allows the technique to utilize longer period data for large events. In selecting the maximum Mb from the frequency-magnitude data the effects of the corner frequency on the event magnitude are also avoided. New work by Veith (2005) defines both the frequency dependent attenuation for P waves and an improved worldwide regional magnitude correction curve. While the need for region specific correction curves is evident, the worldwide average curve together with the frequency dependent attenuation corrections offers significantly improved regional Mb estimates, particularly when combined with this new analysis technique.

  9. Induced p-wave superconductivity without spin-orbit interactions

    NASA Astrophysics Data System (ADS)

    Deus, Fernanda; Continentino, Mucio A.; Caldas, Heron

    2015-11-01

    The study of Majorana fermions is of great importance for the implementation of a quantum computer. These modes are topologically protected and very stable. It is now well known that a p-wave superconducting wire can sustain, in its topological non-trivial phase, Majorana quasi-particles at its ends. Since this type of superconductor is not found in nature, many methods have been devised to implement it. Most of them rely on the spin-orbit interaction. In this paper we study the superconducting properties of a two-band system in the presence of antisymmetric hybridization. We consider inter-band attractive interactions and also an attractive interaction in one of the bands. We show that superconducting fluctuations with p-wave character are induced in the non-interacting band due to the combined effects of inter-band coupling and hybridization. In the case of a wire, this type of induced superconductivity gives rise to four Majorana modes at its ends. The long range correlation between the different charge states of these modes offers new possibilities for the implementation of protected q-bits.

  10. Joint Inversion of Body-Wave Arrival Times and Surface-Wave Dispersion Data in the Wavelet Domain Constrained by Sparsity Regularization

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Fang, H.; Yao, H.; Maceira, M.; van der Hilst, R. D.

    2014-12-01

    Recently, Zhang et al. (2014, Pure and Appiled Geophysics) have developed a joint inversion code incorporating body-wave arrival times and surface-wave dispersion data. The joint inversion code was based on the regional-scale version of the double-difference tomography algorithm tomoDD. The surface-wave inversion part uses the propagator matrix solver in the algorithm DISPER80 (Saito, 1988) for forward calculation of dispersion curves from layered velocity models and the related sensitivities. The application of the joint inversion code to the SAFOD site in central California shows that the fault structure is better imaged in the new model, which is able to fit both the body-wave and surface-wave observations adequately. Here we present a new joint inversion method that solves the model in the wavelet domain constrained by sparsity regularization. Compared to the previous method, it has the following advantages: (1) The method is both data- and model-adaptive. For the velocity model, it can be represented by different wavelet coefficients at different scales, which are generally sparse. By constraining the model wavelet coefficients to be sparse, the inversion in the wavelet domain can inherently adapt to the data distribution so that the model has higher spatial resolution in the good data coverage zone. Fang and Zhang (2014, Geophysical Journal International) have showed the superior performance of the wavelet-based double-difference seismic tomography method compared to the conventional method. (2) For the surface wave inversion, the joint inversion code takes advantage of the recent development of direct inversion of surface wave dispersion data for 3-D variations of shear wave velocity without the intermediate step of phase or group velocity maps (Fang et al., 2014, Geophysical Journal International). A fast marching method is used to compute, at each period, surface wave traveltimes and ray paths between sources and receivers. We will test the new joint inversion code at the SAFOD site to compare its performance over the previous code. We will also select another fault zone such as the San Jacinto Fault Zone to better image its structure.

  11. Global P wave tomography of Earth's lowermost mantle from partition modeling

    NASA Astrophysics Data System (ADS)

    Young, M. K.; Tkal?i?, H.; Bodin, T.; Sambridge, M.

    2013-10-01

    Determining the scale-length, magnitude, and distribution of heterogeneity in the lowermost mantle is crucial to understanding whole mantle dynamics, and yet it remains a much debated and ongoing challenge in geophysics. Common shortcomings of current seismically derived lowermost mantle models are incomplete raypath coverage, arbitrary model parameterization, inaccurate uncertainty estimates, and an ad hoc definition of the misfit function in the optimization framework. In response, we present a new approach to global tomography. Apart from improving the existing raypath coverage using only high-quality cross-correlated waveforms, the problem is addressed within a Bayesian framework where explicit regularization of model parameters is not required. We obtain high-resolution images, complete with uncertainty estimates, of the lowermost mantle P wave velocity structure using a hand-picked data set of PKPab-df, PKPbc-df, and PcP-P differential travel times. Most importantly, our results demonstrate that the root mean square of the P wave velocity variations in the lowermost mantle is approximately 0.87%, which is 3 times larger than previous global-scale estimates.

  12. Rupture history of the 1997 Cariaco, Venezuela, earthquake from teleseismic P waves

    USGS Publications Warehouse

    Mendoza, C.

    2000-01-01

    A two-step finite-fault waveform inversion scheme is applied to the broadband teleseismic P waves recorded for the strike-slip, Cariaco, Venezuela, earthquake of 9 July 1997 to recover the distribution of mainshock slip. The earthquake is first analyzed using a long narrow fault with a maximum rise time of 20 sec. This line-source analysis indicates that slip propagated to the west with a constant rupture velocity and a relatively short rise time. The results are then used to constrain a second inversion of the P waveforms using a 60-km by 20-km two-dimensional fault. The rupture shows a zone of large slip (1.3-m peak) near the hypocenter and a second, broader source extending updip and to the west at depths shallower than 5 km. The second source has a peak slip of 2.1 meters and accounts for most of the moment of 1.1 × 1026 dyne-cm (6.6 Mww) estimated from the P waves. The inferred rupture pattern is consistent with macroseismic effects observed in the epicentral area.

  13. Lifshitz effects on holographic $p$-wave superfluid

    E-print Network

    Ya-Bo Wu; Jun-Wang Lu; Cheng-Yuan Zhang; Nan Zhang; Xue Zhang; Zhuo-Qun Yang; Si-Yu Wu

    2014-12-11

    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 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.

  14. Layer stripping of azimuthal anisotropy from P-wave reflection moveout in orthogonal survey lines

    NASA Astrophysics Data System (ADS)

    Wang, Shangxu; Li, Xiang-Yang

    2006-03-01

    This paper presents a layer-stripping procedure to determine interval measurements of fracture parameters in multi-layered fractured media with vertically varying strike directions. The procedure is based on the P-wave travel time difference between two orthogonal seismic survey lines, and this difference is referred to as the P-wave azimuthal moveout response (AMR). The interval AMR of a fracture target for a fixed offset is a function of cos 2(? - phivi) with respect to the line azimuth ? and the fracture-strike azimuth phivi. Consequently two pairs of orthogonal survey lines can be used to determine the local fracture strike phivi if the interval AMR of the target is known. In the case of a weakly fractured overburden underlain by a fractured target, layer stripping can be achieved through the alignment of the top-target event by performing NMO correction separately for all survey lines. The interval AMR of the target layer may then be calculated from the residual moveout of the bottom-target event, if any. In the general case, a ray-tracing procedure, similar to that used in AVO analysis, is required to perform effective layer stripping. Full-wave modelling is used to verify and illustrate these procedures.

  15. ARRIVAL OF NORTHERN FUR SEALS, CALWRHINUS URSINUS, ON S'I PAUL ISLAND, ALASKA

    E-print Network

    ARRIVAL OF NORTHERN FUR SEALS, CALWRHINUS URSINUS, ON S'I PAUL ISLAND, ALASKA MICHAEL A. BIGG' ABSTRACT The age-specific arrival times and relative numbers of northern fur seals, Callorhinus ltrsinus-82, and a review of the fur seal literature. Arrival times differed by sex, age, and reproductive state. Arrival

  16. The P-wave boundary of the Large-Low Shear Velocity Province beneath the Pacific

    NASA Astrophysics Data System (ADS)

    Frost, Daniel A.; Rost, Sebastian

    2014-10-01

    The Large Low Shear Velocity Provinces (LLSVPs) in the lower mantle represent volumetrically significant thermal or chemical or thermo-chemical heterogeneities. Their structure and boundaries have been widely studied, mainly using S-waves, but much less is known about their signature in the P-wavefield. We use an extensive dataset recorded at USArray to create, for the first time, a high-resolution map of the location, shape, sharpness, and extent of the boundary of the Pacific LLSVP using P(Pdiff)-waves. We find that the northern edge of the Pacific LLSVP is shallow dipping (26° relative to the horizontal) and diffuse (?120 km wide transition zone) whereas the eastern edge is steeper dipping (70°) and apparently sharp (?40 km wide). We trace the LLSVP boundary up to ?500 km above the CMB in most areas, and 700 km between 120° and 90°W at the eastern extent of the boundary. Apparent P-wave velocity drops are ?1-3% relative to PREM, indicating a strong influence of LLSVPs on P-wave velocity, at least in the high-frequency wavefield, in contrast to previous studies. A localised patch with a greater velocity drop of ?15-25% is detected, defined by large magnitude gradients of the travel-time residuals. We identify this as a likely location of an Ultra-Low Velocity Zone (ULVZ), matching the location of a previously detected ULVZ in this area. The boundary of a separate low velocity anomaly, of a similar height to the LLSVP, is detected in the north-west Pacific, matching tomographic images. This outlier appears to be connected to the main LLSVP through a narrow channel close to the CMB and may be in the process of joining or splitting from the main LLSVP. We also see strong velocity increases in the lower mantle to the east of the LLSVP, likely detecting subducted material beneath central America. The LLSVP P-wave boundary is similar to that determined in high-resolution S-wave studies and follows the -0.4% ?VS iso-velocity contour in the S40RTS tomography model. Additionally, the LLSVP boundary roughly matches the shape of the -0.4% ?VP iso-velocity contour of the P-wave model GyPSuM but defines an area more similar to that defined by the 0.0% VP iso-velocity contour. High resolution P-wave velocity determination allows for estimation of the ratio of P- and S-wave velocity anomalies (RS,P) which can be used to indicate dominantly thermal or chemical control of seismic velocities. Although the RS,P is found here to be approximately 2.4, which is indicative of a thermo-chemical anomaly. However, this result contains a large amount of uncertainty and the implications for the origin of LLSVPs likely remain inconclusive. Nonetheless, other observations of the Pacific LLSVP are consistent with a thermo-chemical anomaly whose shape and boundary sharpness are controlled by proximity to active and past subduction.

  17. Simultaneous Determination of Average Thickness and P-wave Speed of the Crust by Virtual Deep Seismic Sounding (VDSS)

    NASA Astrophysics Data System (ADS)

    Kang, D.; Yu, C.; Ning, J.; TAO, K.; Chen, W. P.

    2014-12-01

    Using teleseismic S-waves, VDSS treats the SV-to-P conversion under the free surface (on the station-side) as a virtual source to generate strong, post-critical reflection off the Moho (SsPmp phase). With just a single, good-quality earthquake, arrival-time difference between SsPmp and the direct S-phase (TSsPmp-Ss) can effectively determine the crustal thickness (H) near the receiver. However, there is a strong trade-off between H and P-wave speed (Vp) in the crust. Here we extend VDSS to constrain both H and Vp by taking advantage of the variation in ray-parameters, or incident angles, as a function of epicentral distance. Note that in conventional receiver functions, information contained in data of different ray-parameters is usually lost, because stacking over move-out corrected data is required to get a clear signal. At a given station, we collect data from many events, each with a different ray-parameter of the direct S-phase (ps­). For each event, we 1) estimate the source wavelet of the direct S-wave through particle motion analysis; 2) deconvolve this wavelet from the vertical- and radial-component seismograms (Yu et al., GJI, 2013); and then 3) determine TSsPmp-Ss through waveform modeling. Finally, we analyze data pairs (ps2, T2SsPmp-Ss) to find the best-fitting values of H and Vp. Synthetic tests verify the robustness of the method even with 15% of white noise. Moreover, we applied the method to public domain data from Forrest (FORT), located in the Eucla basin of western Australia. Based on 30 earthquakes from a narrow back-azimuth range (105±15°) but with ps changing from 0.1221 to 0.1349 s/km, we estimate that near FORT, H and Vp are about 44±2 km and 6.67±0.35 km/s, respectively. This crustal thickness is consistent with previous reports - a surprisingly high value for a region where the elevation is less than 200 m. Together with the high Vp, our results imply that the crust has a dense, mafic component.

  18. The correlations between the saturated and dry P-wave velocity of rocks.

    PubMed

    Kahraman, S

    2007-11-01

    Sometimes engineers need to estimate the wet-rock P-wave velocity from the dry-rock P-wave velocity. An estimation equation embracing all rock classes will be useful for the rock engineers. To investigate the predictability of wet-rock P-wave velocity from the dry-rock P-wave velocity, P-wave velocity measurements were performed on 41 different rock types, 11 of which were igneous, 15 of which were sedimentary and 15 of which was metamorphic. In addition to the dry- and wet-rock P-wave velocity measurements, the P-wave velocity changing as a function of saturation degree was studied. Moreover, dry-rock S-wave velocity measurements were conducted. The test results were modeled using Gassmann's and Wood's theory and it was seen that the measured data did not fit the theories. The unconformity is due to the fact that the theories are valid for high-porosity unconsolidated sediments at low frequencies. Gassmann's equation was modified for the rocks except high-porosity unconsolidated sediments. The dry- and wet-rock P-wave velocity values were evaluated using regression analysis. A strong linear correlation between the dry- and wet-rock P-wave velocities was found. Regression analyses were repeated for the rock classes and it was shown that correlation coefficients were increased. Concluding remark is that the derived equations can be used for the prediction of wet-rock P-wave velocity from the dry-rock P-wave velocity. PMID:17624388

  19. [A P-wave detection method based on multi-feature].

    PubMed

    Song, Lixin; Guan, Lili; Wang, Qian; Wang, Yuhong

    2014-04-01

    Generally, P-wave is the wave of low-frequency and low-amplitude, and it could be affected by baseline drift, electromyography (EMG) interference and other noises easily. Not every heart beat contains the P-wave, and it is also a major problem to determine the P-wave exist or not in a heart beat. In order to solve the limitation of suiting the diverse morphological P-wave using wavelet-amplitude-transform algorithm and the limitation of selecting the pseudo-P-wave sample using the wavelet transform and neural network, we presented new P-wave detecting method based on wave-amplitude threshold and using the multi-feature as the input of neural networks. Firstly, we removed the noise of ECG through the wavelet transform, then determined the position of the candidate P-wave by calculating modulus maxima of the wavelet transform, and then determine the P-wave exist or not by wave-amplitude threshold method initially. Finally we determined whether the P-wave existed or not by the neural networks. The method is validated based on the QT database which is supplied with manual labels made by physicians. We compared the detection effect of ECG P-waves, which was obtained with the method developed in the study, with the algorithm of wavelet threshold value and the method based on "wavelet-amplitude-slope", and verified the feasibility of the proposed algorithm. The detected ECG signal, which is recorded in the hospital ECG division, was consistent with the doctor's labels. Furthermore, after detecting the 13 sets of ECG which were 15 min long, the detection rate for the correct P-wave is 99.911%. PMID:25039128

  20. A finite-frequency P-wave tomographic model: images of subducted slabs stagnant above, penetrating through and trapped below the 660-km discontinuity

    NASA Astrophysics Data System (ADS)

    Fukao, Y.; Obayashi, M.

    2012-12-01

    We constructed a new P-wave tomographic model of the mantle using more than ten millions of travel time data. The finite frequency effect of seismic ray was taken into account by calculating banana-donut kernels at 2 Hz for all the first arrival data and at 0.1 Hz for the broadband differential travel time data. Based on this model, a systematic survey was made for subducted slab images around the circum Pacific including Kurile, Honshu, Izu-Bonin, Mariana, Java, Tonga-Kermadec, southern and northern South America, and Central America. This survey clarified a progressive lateral variation of slab configuration along the arc or through the arc to arc, where a subducted slab is in general in one or two of the following four stages: I. slab stagnant above the 660, II. slab penetrating the 660, III. slab trapped in the uppermost lower mantle (660 to ˜1000 km in depth), and IV. slab descending well into the deep lower mantle. The majority of the slab images are either at stage I or III. We interpret I to IV as the successive stages of slab subduction through the transition region with the 660 at the middle, where I and III are relatively stable or neutral stages and II and IV are relatively unstable, transient stages. In particular, we emphasize III as a distinct stage of slab subduction, through which the slab once softened by the phase transition may progressively recover its hardness. Alternatively, the mantle viscosity may not increase stepwise across the 660 but increase gradually throughout the uppermost lower mantle. Plots of hypocentral distribution on tomographic slab images show that deep shocks at depths greater than ˜620 km are a good measure of slab penetration at stage either II or III.

  1. Lithosphere-asthenosphere P-wave reflectivity across Australia

    NASA Astrophysics Data System (ADS)

    Kennett, B. L. N.

    2015-12-01

    A direct image of P-wave reflectivity in the lithosphere and asthenosphere beneath seismic stations is extracted from stacked autocorrelograms of continuous component records. The autocorrelograms emphasise near vertically travelling waves, so that multiples are more muted than in receiver function studies and it is possible to work at higher frequencies than for receiver functions. Across a wide range of geological environments in Australia, in the 0.5-4.0 Hz frequency band, distinct reflections are seen in the crust underlain by weaker reflectivity in the lithosphere and asthenosphere. The base of crustal reflectivity fits well with Moho estimates from other classes of information. Few mantle reflectors have been seen in conventional reflection profiling at frequencies above 10 Hz; the presence of reflections in the 0.5-4.0 Hz band suggests variations on vertical scales of a few hundred metres with amplitudes of the order of 1%. There are slight indications of a change of reflection character in the lower part of the lithosphere in the transition to the asthenosphere. At a few stations there is a very clear lamination at asthenospheric depth, as well as reflections from the base of the S wave low velocity zone. Reflection bands often occur at depths where discontinuities have been inferred from S wave receiver function work at the same station, but would not by themselves be distinctive of a mid-lithosphere discontinuity.

  2. Two-band model of ferromagnetic p-wave superconductors

    NASA Astrophysics Data System (ADS)

    Lörscher, Christopher; Zhang, Jingchuan; Gu, Qiang; Klemm, Richard

    2014-03-01

    We present results on the full angular and temperature dependencies of the upper critical induction, Bc 2(? , ? , T) , for a ferromagnetic p-wave completely broken symmetry state (CBS), in which parallel-spin electron pairing is pinned to only one crystal axis direction, V(k& circ; ,kcirc;') =V0kzkz' , normal to the spontaneuous magnetization direction. We show that the angular dependence of Bc 2 exhibits an anomalous peak at ?* <90° , due to a competition between order parameter anisotropy and effective mass anisotropy. We also propose a two-band model for ferromagnetic superconductors, where we have two ellipsoidal Fermi surfaces (FSs). Using this model, and by assuming a field-dependent anisotropic effective mass on one of the FSs, m? , i(B) , we can fit the experimental data for the low-temperature specific heat ?(B) of URhGe, which exhibits a peak at ?0 H ~ 12 T in the b-axis direction. We provide quantitative fits to experiment, and propose that this model of a field-dependent effective mass can help to understand the reentrant phase of the ferromagnetic superconductor URhGe, and the upward curvature observed in Bc 2 of UCoGe

  3. P-wave tomography and relation between shallow and deep structures beneath the Songliao basin

    NASA Astrophysics Data System (ADS)

    Yang, Qiyan; Wu, Qingju; Ma, Xiaojun; Zhang, Fengxue; Sheng, Yanrui

    2015-08-01

    We selected relative travel-time residuals from teleseismic waveform data using the waveform correction method and imaged the P wave velocity structure beneath Northeast China. In combination with other geophysical data, we discussed the relation between the shallow and deep structures of the area. The results show that there is a primary high-velocity zone with some high- and low-velocity distribution characters beneath the Songliao basin. The low-velocity anomalies may extend down to the upper mantle, and may be the result of material upwelling. The low-velocity anomaly beneath the southern part of the Songliao basin is connected to those beneath the Changbaishan and A'ershan volcanic areas. It may be an upwelling channel from the mantle beneath the Songliao basin and adjacent area. This finding indicates the Songliao basin was a result of asthenospheric upwelling caused by subduction of the Pacific plate under the Eurasian plate.

  4. Coupled ??, KK¯ scattering in P-wave and the ? resonance from lattice QCD

    DOE PAGESBeta

    Wilson, David J.; Briceño, Raúl A.; Dudek, Jozef J.; Edwards, Robert G.; Thomas, Christopher E.

    2015-11-02

    In this study, we determine elastic and coupled-channel amplitudes for isospin-1 meson-meson scattering in $P$-wave, by calculating correlation functions using lattice QCD with light quark masses such that $m_\\pi = 236$ MeV in a cubic volume of $\\sim (4 \\,\\mathrm{fm})^3$. Variational analyses of large matrices of correlation functions computed using operator constructions resembling $\\pi\\pi$, $K\\overline{K}$ and $q\\bar{q}$, in several moving frames and several lattice irreducible representations, leads to discrete energy spectra from which scattering amplitudes are extracted. In the elastic $\\pi\\pi$ scattering region we obtain a detailed energy-dependence for the phase-shift, corresponding to a $\\rho$ resonance, and we extend themore »analysis into the coupled-channel $K\\overline{K}$ region for the first time, finding a small coupling between the channels.« less

  5. Coupled ? ? , K K ¯ scattering in P -wave and the ? resonance from lattice QCD

    NASA Astrophysics Data System (ADS)

    Wilson, David J.; Briceño, Raúl A.; Dudek, Jozef J.; Edwards, Robert G.; Thomas, Christopher E.; Hadron Spectrum Collaboration

    2015-11-01

    We determine elastic and coupled-channel amplitudes for isospin-1 meson-meson scattering in P wave, by calculating correlation functions using lattice QCD with light quark masses such that m?=236 MeV in a cubic volume of ˜(4 fm )3 . Variational analyses of large matrices of correlation functions computed using operator constructions resembling ? ? , K K ¯ and q q ¯, in several moving frames and several lattice irreducible representations, lead to discrete energy spectra from which scattering amplitudes are extracted. In the elastic ? ? scattering region we obtain a detailed energy dependence for the phase shift, corresponding to a ? resonance, and we extend the analysis into the coupled-channel K K ¯ region for the first time, finding a small coupling between the channels.

  6. High-frequency P-wave seismic noise driven by ocean winds Jian Zhang,1

    E-print Network

    Shearer, Peter

    High-frequency P-wave seismic noise driven by ocean winds Jian Zhang,1 Peter Gerstoft,1 and Peter M, J., P. Gerstoft, and P. M. Shearer (2009), High-frequency P-wave seismic noise driven by ocean winds; Gerstoft and Tanimoto, 2007]. Most studies focus on surface-wave energy in seismic noise, although body

  7. Magnitude determination using initial P waves: A single-station Yih-Min Wu,1

    E-print Network

    Wu, Yih-Min

    Magnitude determination using initial P waves: A single-station approach Yih-Min Wu,1 Hsin-Yi Yen,1 the magnitudes of earthquakes and the properties of the first three seconds of the P waves at a single station within 100-km epicentral distance, we found a linear correlation between the magnitudes

  8. Finite-fault source inversion using teleseismic P waves: simple parameterization and rapid analysis

    USGS Publications Warehouse

    Mendoza, C.; Hartzell, S.

    2013-01-01

    We examine the ability of teleseismic P waves to provide a timely image of the rupture history for large earthquakes using a simple, 2D finite?fault source parameterization. We analyze the broadband displacement waveforms recorded for the 2010 Mw~7 Darfield (New Zealand) and El Mayor?Cucapah (Baja California) earthquakes using a single planar fault with a fixed rake. Both of these earthquakes were observed to have complicated fault geometries following detailed source studies conducted by other investigators using various data types. Our kinematic, finite?fault analysis of the events yields rupture models that similarly identify the principal areas of large coseismic slip along the fault. The results also indicate that the amount of stabilization required to spatially smooth the slip across the fault and minimize the seismic moment is related to the amplitudes of the observed P waveforms and can be estimated from the absolute values of the elements of the coefficient matrix. This empirical relationship persists for earthquakes of different magnitudes and is consistent with the stabilization constraint obtained from the L?curve in Tikhonov regularization. We use the relation to estimate the smoothing parameters for the 2011 Mw 7.1 East Turkey, 2012 Mw 8.6 Northern Sumatra, and 2011 Mw 9.0 Tohoku, Japan, earthquakes and invert the teleseismic P waves in a single step to recover timely, preliminary slip models that identify the principal source features observed in finite?fault solutions obtained by the U.S. Geological Survey National Earthquake Information Center (USGS/NEIC) from the analysis of body? and surface?wave data. These results indicate that smoothing constraints can be estimated a priori to derive a preliminary, first?order image of the coseismic slip using teleseismic records.

  9. Anomalous incident-angle and elliptical-polarization rotation of an elastically refracted P-wave

    PubMed Central

    Fa, Lin; Fa, Yuxiao; Zhang, Yandong; Ding, Pengfei; Gong, Jiamin; Li, Guohui; Li, Lijun; Tang, Shaojie; Zhao, Meishan

    2015-01-01

    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. PMID:26244284

  10. Anomalous incident-angle and elliptical-polarization rotation of an elastically refracted P-wave.

    PubMed

    Fa, Lin; Fa, Yuxiao; Zhang, Yandong; Ding, Pengfei; Gong, Jiamin; Li, Guohui; Li, Lijun; Tang, Shaojie; Zhao, Meishan

    2015-01-01

    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. PMID:26244284

  11. Anomalous incident-angle and elliptical-polarization rotation of an elastically refracted P-wave

    NASA Astrophysics Data System (ADS)

    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.

  12. P-wave tomography of eastern North America: Evidence for mantle evolution from Archean to Phanerozoic, and modification during subsequent hot spot tectonism

    NASA Astrophysics Data System (ADS)

    Villemaire, M.; Darbyshire, F. A.; Bastow, I. D.

    2012-12-01

    The unique physical and chemical properties of cratonic lithosphere are thought to be key to its long-term survival and its resistance to pervasive modification by tectonic processes. Study of mantle structure in southeast Canada and the northeast US offers an excellent opportunity to address this issue because the region spans 3 billion years of Earth history, including Archean formation of the Superior craton and younger accretion of terranes to eastern Laurentia during the Proterozoic Grenville and Phanerozoic Appalachian orogenies. Trending NW-SE through each of these terranes is the track of the Great Meteor hot spot, which affected the region during the Mesozoic. Here we study mantle seismic velocity structure beneath this region of eastern North America using tomographic inversion of teleseismic P-wave relative arrival-times recorded by a large-aperture seismograph network. There are no large-scale systematic differences between Superior and Grenville mantle wave speed structure, which may suggest that tectonic stabilization of cratons occurred in a similar fashion during the Archean and Proterozoic. Cratonic lithosphere is largely thought to be resistant to modification by hot spot processes, in contrast to younger terranes where lithospheric erosion and significant magmatism are expected. Low velocities beneath the regions affected by the Great Meteor hot spot are broadest beneath the Paleozoic Appalachian terranes, indicating pervasive modification of the lithosphere during magmatism. The zone of modification narrows considerably into the Proterozoic Grenville province before disappearing completely in the Archean Superior craton, where the surface signature of Mesozoic magmatism is limited to kimberlite eruptions.

  13. Usefulness of the Electrocardiographic P-Wave Axis as a Predictor of Atrial Fibrillation.

    PubMed

    Rangel, Maria Octavia; O'Neal, Wesley T; Soliman, Elsayed Z

    2016-01-01

    The association between abnormal electrocardiographic P-wave axis with atrial fibrillation (AF) has not been systematically studied in community-based populations. We examined the association between abnormal P-wave axis and AF in 4,274 participants (41% men and 95% white) from the Cardiovascular Health Study. Axis values between 0° and 75° were considered normal. AF cases were identified from study electrocardiograms and from hospitalization discharge data. During a median follow-up of 12.1 years, a total of 1,274 participants (30%) developed AF. The incidence rate of AF was 26 cases per 1,000 person-years for those with abnormal P-wave axis and 24 cases per 1,000 person-years for subjects with normal P-wave axis. Abnormal P-wave axis was associated with a 17% increased risk of AF (95% confidence interval 1.03 to 1.33) after adjustment for age, gender, race, education, income, smoking, diabetes, coronary heart disease, stroke, heart failure, heart rate, systolic blood pressure, body mass index, total cholesterol, high-density lipoprotein cholesterol, antihypertensive medications, aspirin, and statins. The results were consistent in subgroup analyses stratified by age, gender, and race. In conclusion, abnormal P-wave axis, a routinely reported electrocardiographic measurement, is associated with an increased risk of AF. This finding suggests a potential role for P-wave axis in AF risk assessment. PMID:26552511

  14. Complex seismic amplitude inversion for P-wave and S-wave quality factors

    NASA Astrophysics Data System (ADS)

    Zong, Zhaoyun; Yin, Xingyao; Wu, Guochen

    2015-07-01

    Stratum quality factors (P-wave and S-wave quality factors, Qp and Qs) have gradually been utilized in the study of physical state of crust and uppermost mantle, tectonic evolution, hydrogeololgy, gas hydrates, petroleum exploration, etc. Different opinions of the seismic attenuation mechanism result in various approaches to estimate the P-wave and S-wave quality factors. Considering the viscoelasticity of the underground medium, the constitutive matrix of the Earth medium is written as the superposition of homogeneous background medium, elastic perturbation medium and viscoelastic perturbation medium. Under the hypothesis of Born integral and stationary phase approximation, the seismic reflectivity is initially raised in terms of P-wave and S-wave moduli, density, P-wave and S-wave quality factors. Furthermore, incorporating the complex seismic traces with the seismic wavelets at different offsets, a two-step inversion approach is proposed to estimate the P-wave and S-wave quality factors. The AVO/AVA Bayesian inversion approach is suggested to estimate the P-wave modulus and S-wave modulus with the real component of the pre-stack seismic data initially. Taking the estimated P-wave and S-wave moduli as prior information, the P-wave and S-wave quality factors are further estimated with the imaginary component of the complex pre-stack seismic data, which is the quadrature of the original data. Finally, synthetic examples demonstrate that the proposed approach is able to estimate P-wave and S-wave quality factors stably and properly, and two field data examples demonstrate that the proposed approach may work as an efficient approach to fluid identification.

  15. Multicomponent seismic data, combining P-wave and converted P-to-SV wave (C-wave) wavefields, provide inde-

    E-print Network

    Texas at Austin, University of

    Multicomponent seismic data, combining P-wave and converted P-to-SV wave (C-wave) wavefields of P-wave and C-wave seismic data for shallow marine sediment characterization, Gulf of Mexico MICHAEL, provide inde- pendent measurements of rock and fluid properties. Unlike P waves, C waves are minimally

  16. Evolution of upper mantle beneath East Asia and the Tibetan Plateau from P-wave tomography

    E-print Network

    Li, Chang, Ph.D.

    2007-01-01

    The main objective of the research presented in this thesis is to improve our understanding for the evolution of the upper mantle beneath East Asia and the Tibetan Plateau through high resolution P-wave tomography. The ...

  17. High-frequency P-wave seismic noise driven by ocean winds

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Gerstoft, Peter; Shearer, Peter M.

    2009-05-01

    Earth's background vibrations at frequencies below about 0.5 Hz have been attributed to ocean-wave energy coupling into the ground and propagating as surface waves and P-waves (compressional waves deep within the Earth). However, the origin and nature of seismic noise on land at frequencies around 1 Hz has not yet been well studied. Using array beamforming, we analyze the seismic noise fields at two remote sites (Parkfield and the Mojave Desert) in California, for durations of one and six months respectively. We find that (1) the seismic background noise at about 0.6-2 Hz consists of a significant amount of continuous P-waves originating offshore, and (2) the power of the P-wave noise is highly correlated with the offshore wind speed, demonstrating that these high-frequency P-waves are excited by distant ocean winds. Our result suggests a land-based seismological proxy for monitoring oceanic weather.

  18. Analysis of P-wave seismic response for fracture detection: modelling and case studies 

    E-print Network

    Xu, Yungui

    2012-06-25

    This thesis addresses a few specific issues in the use of wide azimuth P-wave seismic data for fracture detection based on numerical modelling and real data. These issues include the seismic response of discrete fractures, ...

  19. Mariscope: Observing P Waves (and much more) Everywhere in the Oceans

    NASA Astrophysics Data System (ADS)

    Nolet, G.; Hello, Y.; Bonnieux, S.; Sukhovich, A.; Simons, F. J.

    2014-12-01

    The lack of stations on islands or the ocean bottom deprives seismic tomographers of almost 2/3 of the information potentially available for global seismic tomography. The "Mermaid", developed at Geoazur, is an underwater seismograph, based on a TWR Apex float. P wave signals are automatically identified and transmitted using the detection algorithm from Sukhovich et al. (GRL, 2011), GPS is used to locate the sensor at the time of transmission. We have studied the performance of Mermaids under different noise conditions in the Mediterranean, Indian Ocean and most recently near the Galapagos islands and will show a selection of observations. In the Mediterranean, we regularly detect P waves at teleseismic distances of earthquakes with magnitude 6, occasionally below that. Local and regional earthquakes of much lower magnitude, such as a M 4.9 earthquake near Barcelonette (figure), yield seismograms with a high signal to noise ratio.In the much noisier environment of the Indian Ocean the threshold for useful seismograms is close to magnitude 6.5. Yet we were also able to record 235 low magnitude events when a Mermaid was close to a swarm near the Indian Ocean triple junction, with the lowest magnitude estimated to be 2.1; this sequence also enabled us to put an upper limit of about 250 m to the error in sensor location at the time of recording. Preliminary data from the Galapagos indicate low noise conditions similar to those in the Mediterranean, with good recordings of events in the magnitude 5 range.A new prototype of a spherical "MultiMermaid" is currently being tested. It allows for multidisciplinary observations (seismic and kHz acoustics, magnetic field, temperature, bathymetry) and will function about five years with lithium batteries. A global deployment of such instruments in a five-year program is affordable: project MariScope aims for at least 300 floating seismometers in the world's oceans. At the time of writing of this abstract, a proposal is being prepared that involves geophysicists and biologists from France, Germany, Italy and Greece and should result in a first installment of MariScope. We shall discuss the possibility of a local rapid response network in which the instruments locate themselves while under water.

  20. Pelagic and coastal sources of P-wave microseisms: Generation under tropical cyclones

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Gerstoft, Peter; Bromirski, Peter D.

    2010-08-01

    Nonlinear wave-wave interactions generate double-frequency (DF) microseisms, which include both surface waves (mainly Rayleigh-type) and compressional (P) waves. Although it is unclear whether DF surface waves generated in deep oceans are observed on land, we show that beamforming of land-based seismic array data allows detection of DF P waves generated by ocean waves from Super Typhoon Ioke in both pelagic and coastal regions. Two distinct spectral bands associated with different P-wave source locations are observed. The short-period DF band (0.16-0.35 Hz) is dominated by P waves generated in the deep ocean by local wind seas under the storm. In contrast, P waves in the long-period DF band (0.1-0.15 Hz) are weaker and generated closer to the coast of Japan from swell interactions. The accurate identification of DF P-wave microseism source areas is useful to monitor ocean wave-wave interactions due to tropical cyclones and to image Earth structure using ambient seismic noise.

  1. Model input and output files for the simulation of time of arrival of landfill leachate at the water table, Municipal Solid Waste Landfill Facility, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Frenzel, Peter F.

    1999-01-01

    This report contains listings of model input and output files for the simulation of the time of arrival of landfill leachate at the water table from the Municipal Solid Waste Landfill Facility (MSWLF), about 10 miles northeast of downtown El Paso, Texas. This simulation was done by the U.S. Geological Survey in cooperation with the U.S. Department of the Army, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas. The U.S. Environmental Protection Agency-developed Hydrologic Evaluation of Landfill Performance (HELP) and Multimedia Exposure Assessment (MULTIMED) computer models were used to simulate the production of leachate by a landfill and transport of landfill leachate to the water table. Model input data files used with and output files generated by the HELP and MULTIMED models are provided in ASCII format on a 3.5-inch 1.44-megabyte IBM-PC compatible floppy disk.

  2. Universal High-Momentum Asymptote and Thermodynamic Relations in a Spinless Fermi Gas with a Resonant p -Wave Interaction

    NASA Astrophysics Data System (ADS)

    Yoshida, Shuhei M.; Ueda, Masahito

    2015-09-01

    We investigate universal relations in a spinless Fermi gas near a p -wave Feshbach resonance, and show that the momentum distribution nk has an asymptote proportional to k-2 with the proportionality constant—the p -wave contact—scaling with the number of closed-channel molecules. We prove the adiabatic sweep theorem for a p -wave resonance which reveals the thermodynamic implication of the p -wave contact. In contrast to the unitary Fermi gas in which Tan's contact is universal, the p -wave contact depends on the short-range details of the interaction.

  3. Deep seafloor arrivals: An unexplained set of arrivals in long-range ocean acoustic propagation

    E-print Network

    Frandsen, Jannette B.

    Deep seafloor arrivals: An unexplained set of arrivals in long-range ocean acoustic propagation to predicted ocean acoustic arrivals and deep shadow zone arrivals leaking below turning points , "deep on the hydrophone array, are observed. These deep seafloor arrivals are an unexplained set of arrivals in ocean

  4. Biphasic P wave in inferior leads and the development of atrial fibrillation

    PubMed Central

    Hayashi, Hideki; Horie, Minoru

    2015-01-01

    Background Anisotropic and slow conduction in the atrium underlie the development of atrial fibrillation (AF). This study aimed to investigate the P wave characteristics associated with the development of AF in patients with a biphasic P wave in the inferior leads. Methods Digital analysis of retrospectively recorded 12-lead electrocardiograms was performed to select patients with a biphasic P wave (positive/negative) in lead II from a database of 114,334 patients. Characteristics of the P wave in the inferior leads associated with incidence of AF were determined. Receiver operating characteristic curves dichotomized P wave variables were measured in each lead. Results A total of 141 patients (77 men; mean age, 64±19 years) were enrolled in this study. Twenty-nine (20.6%) patients developed AF (AF group) vs. 112 (79.6%) who did not (non-AF group) during a follow-up period of 50±62 months. The amplitude of the initial P wave portion in lead II was significantly larger in the AF group when compared with the non-AF group (77.3±77.0 µV vs. 51.0±30.1 µV, p=0.003), while the amplitude of the terminal P wave portion in lead III was significantly decreased in the AF group when compared with the non-AF group (?70.6±41.3 µV vs. ?89.1±38.1 µV, p=0.024). The duration of the initial P wave portion in lead III was significantly longer in the AF group when compared with the non-AF group (52.7±34.6 ms vs. 35.8±30.4 ms, p=0.011). Multivariate Cox proportional-hazards analysis confirmed that the increased duration of the initial P wave portion in lead III (?71 ms) was independently associated with AF development (hazard ratio 2.90, 95% confidence interval 1.16–7.11, p=0.02). Conclusion The analyses of the biphasic P wave in the inferior leads suggest that the development of AF could be attributed to increased atrial slow conduction. PMID:26702318

  5. Exploiting the time of arrival of Cherenkov photons at the 28 m H.E.S.S. telescope for background rejection: Methods and performance

    E-print Network

    Chalmé-Calvet, Raphaël; de Naurois, Mathieu; Tavernet, Jean-Paul

    2015-01-01

    In 2012, the High Energy Stereoscopic System (H.E.S.S.) was expanded by a fifth telescope (CT5). With an effective mirror diameter of 28m, CT5 is able to detect the Cherenkov light of very faint gamma-ray air showers, thereby significantly lowering the energy threshold of this telescope compared to the other four telescopes. Extracting as much information as possible from the recorded shower image is crucial for background rejection and to reach an energy threshold of a few tens of GeV. The camera of CT5 is conceived to register the time of the charge pulse maximum with respect to the beginning of the 16 ns integration window of each pixel. This information can be utilised to improve the event reconstruction. It also helps to reduce the background contamination at low energies. We present new techniques for background rejection based on CT5 timing information and evaluate their performance.

  6. Fluid pressure arrival time tomography: Estimation and assessment in the presence of inequality constraints, with an application to a producing gas field at Krechba, Algeria

    SciTech Connect

    Rucci, A.; Vasco, D.W.; Novali, F.

    2010-04-01

    Deformation in the overburden proves useful in deducing spatial and temporal changes in the volume of a producing reservoir. Based upon these changes we estimate diffusive travel times associated with the transient flow due to production, and then, as the solution of a linear inverse problem, the effective permeability of the reservoir. An advantage an approach based upon travel times, as opposed to one based upon the amplitude of surface deformation, is that it is much less sensitive to the exact geomechanical properties of the reservoir and overburden. Inequalities constrain the inversion, under the assumption that the fluid production only results in pore volume decreases within the reservoir. We apply the formulation to satellite-based estimates of deformation in the material overlying a thin gas production zone at the Krechba field in Algeria. The peak displacement after three years of gas production is approximately 0.5 cm, overlying the eastern margin of the anticlinal structure defining the gas field. Using data from 15 irregularly-spaced images of range change, we calculate the diffusive travel times associated with the startup of a gas production well. The inequality constraints are incorporated into the estimates of model parameter resolution and covariance, improving the resolution by roughly 30 to 40%.

  7. Flame Arrival Measurement By Instrumented Spark Plug or Head Gasket

    Energy Science and Technology Software Center (ESTSC)

    1995-04-10

    PLUGBIN was developed to support Sandia technologies involving instrumented head gaskets and spark plugs for engine research and development. It acquires and processes measurements of flame arrival and pressure from a spark ignition. Flame arrival is determined from analog ionization-probe or visible-emission signals, and/or digitial signals from a dedicated flame arrival measurement processor. The pressure measurements are analyzed to determine the time of peak pressure and the time to burn 10 and 90 percent ofmore »the charge. Histograms are then calculated and displayed for each measurement.« less

  8. Application of P-wave hybrid theory to the scattering of electrons from He+ and resonances in He and H-

    NASA Astrophysics Data System (ADS)

    Bhatia, A. K.

    2012-09-01

    The P-wave hybrid theory of electron-hydrogen elastic scattering [Bhatia, Phys. Rev. A10.1103/PhysRevA.85.052708 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 Schrödinger equation at the same time, by using a combination of a modified method of polarized orbitals and the optical potential formalism. The short-range-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. A10.1103/PhysRevA.69.032714 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 also been calculated and compared with the results obtained using the Feshbach projection operator formalism [Bhatia and Temkin, Phys. Rev. A10.1103/PhysRevA.11.2018 11, 2018 (1975)] and also with the results of other calculations. 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 resonances are embedded.

  9. Electric car arrives - again

    SciTech Connect

    Dunn, S.

    1997-03-01

    The first mass-produced electric cars in modern times are here, although they are expensive, limited in capability and unfamiliar to most prospective consumers. This article presents a brief history of the reintroduction of the modern electric car as well as discussions of the limitations of development, alternative routes to both producing and selling electric cars or some modified version of electric cars, economic incentives and governmental policies, and finally a snapshot description of the future for electric cars. 6 refs., 1 tab.

  10. Comparison of interplanetary CME arrival times and solar wind parameters based on the WSA-ENLIL model with three cone types and observations

    NASA Astrophysics Data System (ADS)

    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.

  11. Evaluation of the P Wave Axis in Patients With Systemic Lupus Erythematosus

    PubMed Central

    Acar, Rezzan Deniz; Bulut, Mustafa; Acar, ?encan; Izci, Servet; Fidan, Serdar; Yesin, Mahmut; Efe, Suleyman Cagan

    2015-01-01

    Introduction: P wave axis is one of the most practical clinical tool for evaluation of cardiovascular disease. The aim of our study was to evaluate the P wave axis in electrocardiogram (ECG), left atrial function and association between the disease activity score in patients with systemic lupus erythematosus (SLE). Methods: Standard 12-lead surface ECGs were recorded by at a paper speed of 25 m/s and an amplifier gain of 10 mm/mV. The heart rate (HR), the duration of PR, QRS, QTd (dispersion), the axis of P wave were measured by ECG machine automatically. Results: The P wave axis was significantly increased in patients with SLE (49 ± 20 vs. 40 ± 18, P = 0.037) and the disease activity score was found positively correlated with P wave axis (r: 0.382, P = 0.011). The LA volume and the peak systolic strain of the left atrium (LA) were statistically different between the groups (P = 0.024 and P = 0.000). The parameters of the diastolic function; E/A and E/e’ were better in the control group than the patients with SLE (1.1 ± 0.3 vs. 1.3 ± 0.3, P = 0.041 and 6.6 ± 2.8 vs. 5.4 ± 1.4, P = 0.036, respectively). Conclusion: P wave axis was found significantly increased in patients with SLE and positively correlated with SELENA-SLEDAI score. As the risk score increases in patients with SLE, P wave axis changes which may predict the risk of all-cause and cardiovascular mortality. PMID:26702344

  12. Recording of anomalous shear energy in the teleseismic P-wave coda at Long Valley Caldera, California, on a small aperture array

    SciTech Connect

    Zucca, J.J.; Zandt, G. ); Steck, L.K.; Prothero, W.A. . Dept. of Geology)

    1990-03-01

    Anomalous energy in the coda of teleseismic P-waves at Long Valley caldera has been suggested to be a P to S converted arrival, perhaps with the conversion occurring at the boundaries of magma bodies beneath the caldera. We have collected new data with a small-aperture, three-component array located in the northwestern quadrant of the caldera with the purpose of testing this hypothesis. An examination of three teleseismic events using array and particle motion techniques shows that converted P- to S-waves comprise a significant fraction of the early arriving anomalous energy. In volcanic areas such as Long Valley, the scattered energy could originate at a high velocity contrast feature such as magma body interface. In addition, later arriving energy was detected with slow phase velocity and is tentatively identified as body wave to surface wave scattering. Our interpretation is illustrated with waveforms of two earthquakes from the Kuril Islands and one in northern Peru. Our results show that a small-aperture, three-component array can be used to perform detailed analysis of the coda. 12 refs., 8 figs., 1 tab.

  13. Upper mantle and crustal P-wave attenuation beneath the North Korea region

    NASA Astrophysics Data System (ADS)

    Cleveland, M.; Randall, G. E.; Patton, H. J.; Phillips, W. S.

    2014-12-01

    Accurate estimation of the magnitude of crustal seismic sources is dependent upon a strong understanding of the anelastic P-wave attenuation in the crust and upper mantle. In this study, we estimate the crustal/upper mantle average attenuation (t*) for the region around North Korea by expanding upon methods described by Ichinose et al. [2013]. We estimate t* by modeling the observed spectra and spectral ratio of regional and teleseismic P- and pP-phases of large, deep (> 500 km) earthquakes rupturing beneath the North Korea region. We use seismograms, acquired from the IRIS data archive, from operational stations at the time of each earthquake. Because of a trade-off between the variables, we use multi-variable optimization to estimate the best-fitting corner frequency (fc) and t* for each spectrum. In addition to using a more quantitative and global approach than earlier studies, we introduce new measurement approaches enabling a better understanding of the uncertainty in the measured t* value and its trade-off with fc.

  14. Fracture density estimates in glaciogenic deposits from P-wave velocity reductions

    SciTech Connect

    Karaman, A.; Carpenter, P.J.

    1997-01-01

    Subsidence-induced fracturing of glaciogenic deposits over coal mines in the southern Illinois basis alters hydraulic properties of drift aquifers and exposes these aquifers to surface contaminants. In this study, refraction tomography surveys were used in conjunction with a generalized form of a seismic fracture density model to estimate the vertical and lateral extent of fracturing in a 12-m thick overburden of loess, clay, glacial till, and outwash above a longwall coal mine at 90 m depth. This generalized model accurately predicted fracture trends and densities from azimuthal P-wave velocity variations over unsaturated single- and dual-parallel fractures exposed at the surface. These fractures extended at least 6 m and exhibited 10--15 cm apertures at the surface. The pre- and postsubsidence velocity ratios were converted into fracture densities that exhibited qualitative agreement with the observed surface and inferred subsurface fracture distribution. Velocity reductions as large as 25% were imaged over the static tension zone of the mine where fracturing may extend to depths of 10--15 m. Finally, the seismically derived fracture density estimates were plotted as a function of subsidence-induced drawdown across the panel to estimate the average specific storage of the sand and gravel lower drift aquifer. This value was at least 20 times higher than the presubsidence (unfractured) specific storage for the same aquifer.

  15. Acoustic Source Localization via Time Difference of Arrival Estimation for Distributed Sensor Networks using Tera-scale Optical-Core Devices

    SciTech Connect

    Imam, Neena; Barhen, Jacob

    2009-01-01

    For real-time acoustic source localization applications, one of the primary challenges is the considerable growth in computational complexity associated with the emergence of ever larger, active or passive, distributed sensor networks. These sensors rely heavily on battery-operated system components to achieve highly functional automation in signal and information processing. In order to keep communication requirements minimal, it is desirable to perform as much processing on the receiver platforms as possible. However, the complexity of the calculations needed to achieve accurate source localization increases dramatically with the size of sensor arrays, resulting in substantial growth of computational requirements that cannot be readily met with standard hardware. One option to meet this challenge builds upon the emergence of digital optical-core devices. The objective of this work was to explore the implementation of key building block algorithms used in underwater source localization on the optical-core digital processing platform recently introduced by Lenslet Inc. This demonstration of considerably faster signal processing capability should be of substantial significance to the design and innovation of future generations of distributed sensor networks.

  16. What Do s- and p-Wave Neutron Average Radiative Widths Reveal

    SciTech Connect

    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.

  17. 3D image of an active magma chamber beneath Montserrat, Lesser Antilles, from first-arrival travel-time tomography (Invited)

    NASA Astrophysics Data System (ADS)

    Paulatto, M.; Annen, C.; Henstock, T.; Kiddle, E. J.; Minshull, T. A.; Sparks, R. S.; Foroozan, R.

    2010-12-01

    Andesitic magma erupted at island arc strato-volcanoes is stored in the shallow crust prior to eruption. Constraining the size, location and characteristics of magma reservoirs is key to forecasting the likelihood and characteristics of future eruptions. The island of Montserrat, in the Lesser Antilles, has been the subject of an active-source seismic tomography experiment (the SEA-CALIPSO experiment) with the main aim of studying the magmatic system of the active Soufriere Hills Volcano (SHV). We present the results of the three-dimensional travel-time inversion of the dataset. We are able to image the main features of the volcanic system of the island including SHV and the two older and extinct volcanoes. The shallow structure is dominated by the presence of high-velocity cores beneath the three volcanic centres. Beneath SHV at depth between 5 and 8 km we observe a negative velocity anomaly (NVA) roughly 4 km across. Checkerboard tests show that a pattern with wavelength similar to the size of the anomaly is well resolved at up to 7 km depth therefore the lower limit of the low velocity region is not constrained by our data. We show that in this case the resolution limit is in part determined by the bandwidth of the illuminating seismic source, as well as the experiment geometry. Temperature estimates at the centre of the NVA calculated with respect to the average velocity structure of the island indicate that a significant region is at temperature above the solidus of andesite and thus require the presence of melt. To further constrain the nature of the NVA we compare the observed seismic velocities with those predicted by thermal and geochemical models of melt intrusions in the upper crust. The thermal models show that the observed NVA is compatible with the presence of a magma storage region of 20-40 cubic kilometers, formed by repeated emplacement of horizontal sills over thousands of years. This shallow magma storage region is likely to correspond to the source of andesitic magma in the shallow crust feeding the current eruption.

  18. Scheduling and Separating Departures Crossing Arrival Flows in Shared Airspace

    NASA Technical Reports Server (NTRS)

    Chevalley, Eric; Parke, Bonny K.; Lee, Paul; Omar, Faisal; Lee, Hwasoo; Beinert, Nancy; Kraut, Joshua M.; Palmer, Everett

    2013-01-01

    Flight efficiency and reduction of flight delays are among the primary goals of NextGen. In this paper, we propose a concept of shared airspace where departures fly across arrival flows, provided gaps are available in these flows. We have explored solutions to separate departures temporally from arrival traffic and pre-arranged procedures to support controllers' decisions. We conducted a Human-in-the-Loop simulation and assessed the efficiency and safety of 96 departures from the San Jose airport (SJC) climbing across the arrival airspace of the Oakland and San Francisco arrival flows. In our simulation, the SJC tower had a tool to schedule departures to fly across predicted gaps in the arrival flow. When departures were mistimed and separation could not be ensured, a safe but less efficient route was provided to the departures to fly under the arrival flows. A coordination using a point-out procedure allowed the arrival controller to control the SJC departures right after takeoff. We manipulated the accuracy of departure time (accurate vs. inaccurate) as well as which sector took control of the departures after takeoff (departure vs. arrival sector) in a 2x2 full factorial plan. Results show that coordination time decreased and climb efficiency increased when the arrival sector controlled the aircraft right after takeoff. Also, climb efficiency increased when the departure times were more accurate. Coordination was shown to be a critical component of tactical operations in shared airspace. Although workload, coordination, and safety were judged by controllers as acceptable in the simulation, it appears that in the field, controllers would need improved tools and coordination procedures to support this procedure.

  19. Effect of a low-velocity sedimentary cover on the 3-D velocity models derived from inversion of local arrival times. An example from the New Madrid seismic zone.

    NASA Astrophysics Data System (ADS)

    Pujol, J. M.; Chiu, J. M.

    2014-12-01

    When applying seismic tomography to local arrival times from an area with a low-velocity sedimentary cover, the effect of the sediments on travel times should be taken into account. If that is not done, the resulting velocity model(s) cannot be assumed to be correct. This fairly obvious statement has been challenged recently by Powell et al. (JGR, 2010), who claimed that the sediments that cover the New Madrid seismic zone (NMSZ, central United States) can be ignored. This claim is examined here and shown to be incorrect. The NMSZ is covered by low-velocity, poorly consolidated sediments (Vp=1.8 km/s, Vs=3), which are underlain by Paleozoic rocks of much higher velocity. In the central NMSZ the sediment thickness varies between about 0.1 and 0.7 km. The JHD analysis of the data collected in that area by a portable network (PANDA) showed that the P- and S-wave station corrections spanned large ranges (0.35 and 0.63 s, respectively, Pujol et al., Eng. Geol., 1997). This study also showed that a Vp/Vs of 3 for the sediments would be too high if the lateral velocity variations were confined to the sedimentary cover. Here we generate synthetic traveltimes for a model with a sedimentary cover having variable depth (as determined from boreholes) underlain by the high-velocity layers in the 1-D model used for the JHD analysis. The synthetic data were generated for the station and event distributions corresponding to the Panda data. The tomographic inversion of the synthetic times produces spurious anomalies in Vp, Vs, and Vp/Vs, from the surface to a depth of 10 km. In addition, the events are mislocated in depth, with errors between 0 and 1 km for most of them. These results should dispel the notion that the effect of the unconsolidated sediments can be ignored. On the other hand, the inversion of the actual Panda data results in velocity anomalies similar to the synthetic anomalies, although larger, which is consistent with the conclusions of Pujol et al. (1997). Unfortunately, extricating the effects of the sediments from those of deeper velocity anomalies will not be possible with seismic tomography unless in-situ determinations of Vp/Vs for the sediments in the network area become available. Alternatively, analysis techniques that make use of more than just P- and S-wave arrivals (such as S-to-P converted waves) may have to be designed.

  20. A Powerful Twin Arrives

    NASA Astrophysics Data System (ADS)

    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 may be used in several different observation modes. FORS2 is largely identical to FORS1 , but there are a number of important differences. For example, it contains a Mask Exchange Unit (MXU) for laser-cut star-plates [1] that may be inserted at the focus, allowing a large number of spectra of different objects, in practice up to about 70, to be taken simultaneously. Highly sophisticated software assigns slits to individual objects in an optimal way, ensuring a great degree of observing efficiency. Instead of the polarimetry optics found in FORS1 , FORS2 has new grisms that allow the use of higher spectral resolutions. The FORS project was carried out under ESO contract by a consortium of three German astronomical institutes, the Heidelberg State Observatory and the University Observatories of Göttingen and Munich. The participating institutes have invested a total of about 180 man-years of work in this unique programme. The photos below demonstrate some of the impressive possibilities with this new instrument. They are based on observations with the FORS2 standard resolution collimator (field size 6.8 x 6.8 armin = 2048 x 2048 pixels; 1 pixel = 0.20 arcsec). In addition, observations of the Crab pulsar demonstrate a new observing mode, high-speed photometry. Protostar HH-34 in Orion ESO PR Photo 40b/99 ESO PR Photo 40b/99 [Preview - JPEG: 400 x 444 pix - 220kb] [Normal - JPEG: 800 x 887 pix - 806kb] [Full-Res - JPEG: 2000 x 2217 pix - 3.6Mb] The Area around HH-34 in Orion ESO PR Photo 40c/99 ESO PR Photo 40c/99 [Preview - JPEG: 400 x 494 pix - 262kb] [Full-Res - JPEG: 802 x 991 pix - 760 kb] The HH-34 Superjet in Orion (centre) PR Photo 40b/99 shows a three-colour composite of the young object Herbig-Haro 34 (HH-34) , now in the protostar stage of evolution. It is based on CCD frames obtained with the FORS2 instrument in imaging mode, on November 2 and 6, 1999. This object has a remarkable, very complicated appearance that includes two opposite jets that ram into the surrounding interstellar matter. This structure is produced by a machine-gu

  1. Collaborative Arrival Planning: Data Sharing and User Preference Tools

    NASA Technical Reports Server (NTRS)

    Zelenka, Richard E.; Edwards, Thomas A. (Technical Monitor)

    1998-01-01

    Air traffic growth and air carrier economic pressures have motivated efforts to increase the flexibility of the air traffic management process and change the relationship between the air traffic control service provider and the system user. One of the most visible of these efforts is the U.S. government/industry "free flight" initiative, in which the service provider concentrates on safety and cross-airline fairness, and the user on their business objectives and operating preferences, including selecting their own path and speed in real-time. In the terminal arrival phase of flight, severe restrictions and rigid control are currently placed on system users, typically without regard for individual user operational preferences. Airborne delays applied to arriving aircraft into capacity constrained airports are imposed on a first-come, first-serve basis, and thus do not allow the system user to plan for or prioritize late arrivals, or to economically optimize their arrival sequence. A central tenant of the free-flight operating paradigm is collaboration between service providers and users in reaching air traffic management decisions. Such collaboration would be particularly beneficial to an airline's "hub" operation, where off-schedule arrival aircraft are a consistent problem, as they cause serious air-port ramp difficulties, rippling airline scheduling effects, and result in large economic inefficiencies. Greater collaboration can also lead to increased airport capacity and decrease the severity of over-capacity rush periods. In the NASA Collaborative Arrival Planning (CAP) project, both independent exchange of real-time data between the service provider and system user and collaborative decision support tools are addressed. Data exchange of real-time arrival scheduling, airspace management, and air carrier fleet data between the FAA service provider and an air carrier is being conducted and evaluated. Collaborative arrival decision support tools to allow intra-airline arrival preferences are being developed and simulated. The CAP project is part of and leveraged from the NASA/FAA Center TRACON Automation System (CTAS), a fielded set of decision support tools that provide computer generated advisories for both enroute and terminal area controllers to manage and control arrival traffic more efficiently. In this paper, the NASA Collaborative Arrival Planning project is outlined and recent results detailed, including the real-time use of CTAS arrival scheduling data by a major air carrier and simulations of tactical and strategic user preference decision support tools.

  2. Universal Relations for a Fermi Gas Close to a p -Wave Interaction Resonance

    NASA Astrophysics Data System (ADS)

    Yu, Zhenhua; Thywissen, Joseph H.; Zhang, Shizhong

    2015-09-01

    We investigate the properties of a spinless Fermi gas close to a p -wave interaction resonance. We show that the effects of interaction near a p -wave resonance are captured by two contacts, which are related to the variation of energy with the p -wave scattering volume v and with the effective range R in two adiabatic theorems. Exact pressure and virial relations are derived. We show how the two contacts determine the leading and subleading asymptotic behavior of the momentum distribution (˜1 /k2 and ˜1 /k4) and how they can be measured experimentally by radio-frequency and photoassociation spectroscopies. Finally, we evaluate the two contacts at high temperature with a virial expansion.

  3. Competition between the s-wave and p-wave superconductivity phases in a holographic model

    E-print Network

    Zhang-Yu Nie; Rong-Gen Cai; Xin Gao; Hui Zeng

    2013-11-22

    We build a holographic superconductor model with a scalar triplet charged under an SU(2) gauge field in the bulk. In this model, the s-wave and p-wave condensates can be consistently realized. We find that there are totally four phases in this model, namely, the normal phase without any condensate, s-wave phase, p-wave phase and the s+p coexisting phase. By calculating Gibbs free energy, the s+p coexisting phase turns out to be thermodynamically favored once it can appear. The phase diagram with the dimension of the scalar operator and temperature is drawn. The temperature range for the s+p coexisting phase is very narrow, which shows the competition between the s-wave and p-wave orders in the superconductor model.

  4. P-wave-enhanced spin field effect transistor and recent patents.

    PubMed

    Gau, Ming-Hong; Lo, Ikai; Wang, Wan-Tsang; Chiang, Jih-Chen; Chou, Mitch Ming-Chi

    2007-01-01

    P-wave-enhanced spin field-effect transistor made of AlGaN/GaN heterostructure was designed for the spintronic devices operated at high power and high temperature. The operation theory is based on the spin-polarized field-effect transistor designed by Datta and Das [Appl. Phys. Lett. 56, 665 (1990)]. The mechanism of the p-wave enhancement in AlGaN/GaN heterostructure was investigated. The recent development and related patents in the spin-polarized field-effect transistor were reviewed. In particular, we will focus on the recent patents which could enhance p-wave probability and control of spin precession of 2DEG in the AlGaN/GaN transistor structure. PMID:19076030

  5. Finite-momentum superfluidity and phase transitions in a p-wave resonant Bose gas

    SciTech Connect

    Choi, Sungsoo; Radzihovsky, Leo

    2011-10-15

    We study a degenerate two-species gas of bosonic atoms interacting through a p-wave Feshbach resonance as, for example, realized in a {sup 85}Rb-{sup 87}Rb mixture. We show that, in addition to a conventional atomic and a p-wave molecular spinor-1 superfluidity at large positive and negative detunings, respectively, the system generically exhibits a finite-momentum atomic-molecular superfluidity at intermediate detuning around the unitary point. We analyze the detailed nature of the corresponding phases and the associated quantum and thermal phase transitions.

  6. Proximity effect in ferromagnet/triplet p-wave superconductor structures

    NASA Astrophysics Data System (ADS)

    Li, Hong; Yang, Wei; Yang, Xinjian; Qin, Minghui

    2007-02-01

    The superconducting proximity effect in normal metal/insulator/ferromagnet/triplet p-wave superconductor (N/I/FP) structures is studied based on an extended Blonder Tinkham Klapwijk (BTK) theory. Three kinds of pairings for the P side are chosen: p, p, p+ip waves. The transition from the “0” to “?” state is found in the conductance spectra with increasing the thickness of F or the ferromagnetic exchange energy. The large amplitude of the normalized conductance suggests the possible coexistence of the ferromagnetism and p-wave superconductivity in a small region near the F/P interface induced by the proximity effect.

  7. Rupture imaging of the Mw 7.9 12 May 2008 Wenchuan earthquake from back projection of teleseismic P waves

    USGS Publications Warehouse

    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 earthquakes in near-real time. Copyright 2009 by the American Geophysical Union.

  8. Geohydrology of the unsaturated zone and simulated time of arrival of landfill leachate at the water table, municipal solid waste landfill facility, US Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Frenzel, Peter F.; Abeyta, Cynthia G.

    1999-01-01

    The U.S. Air Defense Artillery Center and Fort Bliss Municipal Solid Waste Landfill Facility (MSWLF) is located about 10 miles northeast of downtown El Paso, Texas. The landfill is built on the Hueco Bolson, a deposit that yields water to five public-supply wells within 1.1 miles of the landfill boundary on all sides. The bolson deposits consist of lenses and mixtures of sand, clay, silt, gravel, and caliche. The unsaturated zone at the landfill is about 300 feet thick. The Hydrologic Evaluation of Landfill Performance (HELP) and the Multimedia Exposure Assessment Model for Evaluating the Land Disposal of Wastes (MULTIMED) computer models were used to simulate the time of first arrival of landfill leachate at the water table. Site-specific data were collected for model input. At five sites on the landfill cover, hydraulic conductivity was measured by an in situ method; in addition, laboratory values were obtained for porosity, moisture content at field capacity, and moisture content at wilting point. Twenty-seven sediment samples were collected from two adjacent boreholes drilled near the southwest corner of the landfill. Of these, 23 samples were assumed to represent the unsaturated zone beneath the landfill. The core samples were analyzed in the laboratory for various characteristics required for the HELP and MULTIMED models: initial moisture content, dry bulk density, porosity, saturated hydraulic conductivity, moisture retention percentages at various suction values, total organic carbon, and pH. Parameters were calculated for the van Genuchten and Brooks-Corey equations that relate hydraulic conductivity to saturation. A reported recharge value of 0.008 inch per year was estimated on the basis of soil- water chloride concentration. The HELP model was implemented using input values that were based mostly on site-specific data or assumed in a conservative manner. Exceptions were the default values used for waste characteristics. Flow through the landfill was assumed to be at steady state. The HELP-estimated landfill leakage rate was 101.6 millimeters per year, approximately 500 times the estimated recharge rate for the area near the landfill. The MULTIMED model was implemented using input values that were based mainly on site-specific data and some conservatively assumed values. Landfill leakage was assumed to begin when the landfill was established and to continue at a steady-state rate of 101.6 millimeters per year as estimated by the HELP model. By using an assumed solute concentration in the leachate of 1 milligram per liter and assuming no delay or decay of solute, the solute serves as a tracer to indicate the first arrival of landfill leachate. The simulated first arrival of leachate at the water table was 204 to 210 years after the establishment of the landfill.

  9. Gamma-Ray Burst Arrival Time Localizations: Simultaneous Observations by {ital Pioneer} {ital V}{ital enus} {ital Orbiter}, {ital Compton} {ital Gamma}-{ital Ray} {ital Observatory}, and {ital Ulysses}

    SciTech Connect

    Laros, J.G.; Hurley, K.C.; Fenimore, E.E.; Klebesadel, R.W.; Briggs, M.S.; Kouveliotou, C.; McCollough, M.L.

    1998-10-01

    Between the {ital Compton} {ital Gamma} {ital Ray} {ital Observatory} ({ital CGRO}) launch in 1991 April and the {ital Pioneer} {ital V}{ital enus} {ital Orbiter} ({ital PVO}) demise in 1992 October, concurrent coverage by {ital CGRO}, {ital PVO}, and {ital Ulysses} was obtained for several hundred gamma-ray bursts (GRBs). Although most of these were below the {ital PVO} and {ital Ulysses} thresholds, 37 were positively detected by all three spacecraft, with data quality adequate for quantitative localization analysis. All were localized independently to {approximately}2{degree} accuracy by the {ital 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{prime} to several degrees and whose smaller dimensions are in the arcminute range. Twelve have areas less than 10 arcmin{sup 2}, and only four have areas greater than 1 deg{sup 2}. The area of the smallest box is 0.44 arcmin{sup 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 {ital 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} {ital {copyright} 1998.} {ital The American Astronomical Society}

  10. Field comparison of shallow P-Wave seismic sources near Houston, Texas

    E-print Network

    Miller, Richard D.; Pullan, Susan E.; Steeples, Don W.; Hunter, James A.

    1994-11-01

    A shallow P?wave seismic source comparison was conducted at a site near Houston, Texas where the depth to the water table was approximately 7 m, and near?surface materials consisted of clays, sands, and gravels. Data from twelve different sources...

  11. P-wave holographic superconductor/insulator phase transitions affected by dark matter sector

    E-print Network

    Marek Rogatko; Karol I. Wysokinski

    2015-08-12

    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 one. In the probe limit approximation, we analytically examine the properties of the first two models in the theory with {\\it 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 superconducting transition temperature increases with the growth of the {\\it dark matter} sector coupling constant $\\alpha$, while the critical chemical potential $\\mu_c$ for the quantum phase transition between insulator and metal is a decreasing function of $\\alpha$.

  12. Magnitude estimation using the first three seconds P-wave amplitude in earthquake early warning

    E-print Network

    Wu, Yih-Min

    Magnitude estimation using the first three seconds P-wave amplitude in earthquake early warning Yih as a function of magnitude M, and obtained the following relationship: log (Pd) = À3.463 + 0.729 Â M À 1.374 Â to the epicenter, this relationship can be used to define a so-called ``Pd magnitude'' of earthquakes. Our result

  13. Pelagic and coastal sources of P wave microseisms: Generation under tropical cyclones

    E-print Network

    Gerstoft, Peter

    Pelagic and coastal sources of P wave microseisms: Generation under tropical cyclones Jian Zhang,1 wave wave interactions due to tropical cyclones and to image Earth structure using ambient seismic wave microseisms: Generation under tropical cyclones, Geophys. Res. Lett., 37, L15301, doi:10

  14. Anisotropic changes in P-wave velocity and attenuation during deformation and fluid infiltration of granite

    USGS Publications Warehouse

    Stanchits, S.A.; Lockner, D.A.; Ponomarev, A.V.

    2003-01-01

    Fluid infiltration and pore fluid pressure changes are known to have a significant effect on the occurrence of earthquakes. Yet, for most damaging earthquakes, with nucleation zones below a few kilometers depth, direct measurements of fluid pressure variations are not available. Instead, pore fluid pressures are inferred primarily from seismic-wave propagation characteristics such as Vp/Vs ratio, attenuation, and reflectivity contacts. We present laboratory measurements of changes in P-wave velocity and attenuation during the injection of water into a granite sample as it was loaded to failure. A cylindrical sample of Westerly granite was deformed at constant confining and pore pressures of 50 and 1 MPa, respectively. Axial load was increased in discrete steps by controlling axial displacement. Anisotropic P-wave velocity and attenuation fields were determined during the experiment using an array of 13 piezoelectric transducers. At the final loading steps (86% and 95% of peak stress), both spatial and temporal changes in P-wave velocity and peak-to-peak amplitudes of P and S waves were observed. P-wave velocity anisotropy reached a maximum of 26%. Transient increases in attenuation of up to 483 dB/m were also observed and were associated with diffusion of water into the sample. We show that velocity and attenuation of P waves are sensitive to the process of opening of microcracks and the subsequent resaturation of these cracks as water diffuses in from the surrounding region. Symmetry of the orientation of newly formed microcracks results in anisotropic velocity and attenuation fields that systematically evolve in response to changes in stress and influx of water. With proper scaling, these measurements provide constraints on the magnitude and duration of velocity and attenuation transients that can be expected to accompany the nucleation of earthquakes in the Earth's crust.

  15. Fluorescence assay for polymerase arrival rates

    E-print Network

    Che, Austin, 1979-

    2004-01-01

    To engineer complex synthetic biological systems will require modular design, assembly, and characterization strategies. The RNA polymerase arrival rate (PAR) is defined to be the rate that RNA polymerases arrive at a ...

  16. Fluorescence Assay for Polymerase Arrival Rates

    E-print Network

    Che, Austin

    2003-08-31

    To engineer complex synthetic biological systems will require modular design, assembly, and characterization strategies. The RNA polymerase arrival rate (PAR) is defined to be the rate that RNA polymerases arrive at a ...

  17. The rupture process and asperity distribution of three great earthquakes from long-period diffracted P-waves

    NASA Technical Reports Server (NTRS)

    Ruff, L.; Kanamori, H.

    1983-01-01

    The variation of maximum earthquake size along the subduction zones has been interpreted as a variation in the seismic coupling ostensibly related to the mechanical conditions of the fault zone. Great differences are noted between the seismographs of the three great earthquakes whose rupture processes are presently considered: in the Kurile Islands (1963), The Rat Islands (1965) and Alaska (1964). On-scale long period P waves were recorded in all cases. Source time functions are deconvolved from the observed periods. It is concluded that maximum earthquake size is related to the asperity distribution on the fault. The subduction zones with the largest earthquakes have very large asperities, as in the Alaskan case, while the zones with the smaller great earthquakes, such as the Kurile Islands, have smaller scattered asperities.

  18. Approximate P-wave ray tracing and dynamic ray tracing in weakly orthorhombic media of varying symmetry orientation

    E-print Network

    Cerveny, Vlastislav

    Approximate P-wave ray tracing and dynamic ray tracing in weakly orthorhombic media of varying, but efficient and sufficiently accurate P-wave ray tracing and dynamic ray tracing procedure for 3D symmetry planes have drawn increased attention. Ray tracing in such media has many potential applications

  19. In-situ, high-frequency P-Wave velocity measurements within 1 m of the Earth’s surface

    E-print Network

    Baker, Gregory S.; Steeples, Don W.; Schmeissner, Chris M.

    1999-03-01

    Seismic P-wave velocities in near?surface materials can be much slower than the speed of sound waves in air (normally 335 m/s or 1100 ft/s). Difficulties often arise when measuring these low?velocity P-waves because of interference by the air wave...

  20. P-wave velocity structure of the crust and uppermost mantle beneath Iceland from local earthquake tomography

    E-print Network

    Shen, Yang

    P-wave velocity structure of the crust and uppermost mantle beneath Iceland from local earthquake develop a three-dimensional P-wave velocity model of the Icelandic crust and uppermost mantle from a broad low-velocity anomaly in the middle and lower crust underlying a high velocity body in the shallow

  1. Deep seafloor arrivals in long range ocean acoustic propagation.

    PubMed

    Stephen, Ralph A; Bolmer, S Thompson; Udovydchenkov, Ilya A; Worcester, Peter F; Dzieciuch, Matthew A; Andrew, Rex K; Mercer, James A; Colosi, John A; Howe, Bruce M

    2013-10-01

    Ocean bottom seismometer observations at 5000 m depth during the long-range ocean acoustic propagation experiment in the North Pacific in 2004 show robust, coherent, late arrivals that are not readily explained by ocean acoustic propagation models. These "deep seafloor" arrivals are the largest amplitude arrivals on the vertical particle velocity channel for ranges from 500 to 3200 km. The travel times for six (of 16 observed) deep seafloor arrivals correspond to the sea surface reflection of an out-of-plane diffraction from a seamount that protrudes to about 4100 m depth and is about 18 km from the receivers. This out-of-plane bottom-diffracted surface-reflected energy is observed on the deep vertical line array about 35 dB below the peak amplitude arrivals and was previously misinterpreted as in-plane bottom-reflected surface-reflected energy. The structure of these arrivals from 500 to 3200 km range is remarkably robust. The bottom-diffracted surface-reflected mechanism provides a means for acoustic signals and noise from distant sources to appear with significant strength on the deep seafloor. PMID:24116525

  2. Investigation on relationship between epicentral distance and growth curve of initial P-wave propagating in local heterogeneous media for earthquake early warning system

    NASA Astrophysics Data System (ADS)

    Okamoto, Kyosuke; Tsuno, Seiji

    2015-12-01

    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 can improve, which will in turn improve the accuracy of the EEW system.

  3. Transverse spin current in the s-wave/p-wave Josephson junction

    NASA Astrophysics Data System (ADS)

    Zhang, Huan; Chan, K. S.; Lin, Zijing; Wang, J.

    2011-10-01

    We report a theoretical study on spin transport in the hybrid Josephson junction composed of singlet s-wave and triplet p-wave superconductor. The node of the triplet pair potential is considered perpendicular to the interface of the junction. Based on a symmetry analysis, we predict that there is no net spin density at the interface of the junction but instead a transverse mode-resolved spin density can exist and a nonzero spin current can flow transversely along the interface of the junction. The predictions are numerically demonstrated by means of the lattice Matsubara Green’s function method. It is also shown that, when a normal metal is sandwiched in between two superconductors, both spin current and transverse mode-resolved spin density are only residing at two interfaces due to the smearing effect of the multimode transport. Our findings are useful for identifying the pairing symmetry of the p-wave superconductor and generating spin current.

  4. Properties of skyrmions and multi-quanta vortices in chiral p-wave superconductors

    PubMed Central

    Garaud, Julien; Babaev, Egor

    2015-01-01

    Chiral p-wave superconducting state supports a rich spectrum of topological excitations different from those in conventional superconducting states. Besides domain walls separating different chiral states, chiral p-wave state supports both singular and coreless vortices also interpreted as skyrmions. Here, we present a numerical study of the energetic properties of isolated singular and coreless vortex states as functions of anisotropy and magnetic field penetration length. In a given chiral state, single quantum vortices with opposite winding have different energies and thus only one kind is energetically favoured. We find that with the appropriate sign of the phase winding, two-quanta (coreless) vortices are always energetically preferred over two isolated single quanta (singular) vortices. We also report solutions carrying more flux quanta. However those are typically more energetically expensive/metastable as compared to those carrying two flux quanta. PMID:26631985

  5. Electron-He(+) P-wave Elastic Scattering and Photoabsorption in Two-electron Systems

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.

    2006-01-01

    In a previous paper [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.

  6. Q for P waves in the sediments of the Virginia Coastal Plain

    USGS Publications Warehouse

    Chapman, M.C.; Beale, J.N.; Catchings, R.D.

    2008-01-01

    The seismic quality factor Q for P waves in Atlantic Coastal Plain sediments is estimated using data from the 2004 U.S. Geological Survey seismic survey in eastern Virginia. The estimates are based on spectral ratios derived from reflections and sediment-guided P waves in Late Cretaceous and Tertiary sediments within the annular trough of the Late Eocene Chesapeake Bay impact structure. The estimates of Q for the frequency range of 10-150 Hz are from 75 to 100, with the best estimate of 80 based on multichannel stacking of spectral ratios from receivers in the offset range of 200-2000 m. This result is approximately a factor of 2 larger than the results previously reported for the Charleston, South Carolina, area, and it is approximately one-half of that recently reported for the Mississippi Embayment.

  7. Anisotropic characteristics of mesoscale fractures and applications to wide azimuth 3D P-wave seismic data

    NASA Astrophysics Data System (ADS)

    Wang, Yaojun; Chen, Shuangquan; Li, Xiang-Yang

    2015-06-01

    Mesoscale fractures of length on the order of centimeters to meters play a crucial role in fluid flow and hydrocarbon production in fractured reservoirs, and are of great interest to reservoir engineers. Therefore, we need to find a method for obtaining information on mesoscale fractures. Most information on fractures comes from seismic data, specifically through the study of fracture-induced azimuthal anisotropic attributes, such as velocity variation with azimuth (VVAZ), amplitude variation with azimuth (AVAZ) and Q (quality factor for attenuation) variation with azimuth (QVAZ). Using these anisotropic attributes to characterize fracture orientations and densities has been performed for a long time. However, it has not been reported whether these methods can be used to detect mesoscale fractures. In this study, through analysis of the anisotropic response to different lengths of fractures based on a mesoscale fracture model, we find that azimuthal anisotropic attenuation is only sensitive to mesoscale fractures, while the anisotropic velocity represents the response for overall scale fractures. Two models, containing mesoscale fractures of length 1?m and microscale fractures of length 0.01?m, are used to calculate synthetic seismograms. Through analysis of the azimuthal anisotropic attributes (VVAZ, AVAZ and QVAZ) from the synthetic seismograms, the identification ability for microscale and mesoscale fractures is compared. It is observed that QVAZ can be used to invert mesoscale fractures while VVAZ and AVAZ cannot. Finally, the QVAZ method is applied in a wide azimuth 3D P-wave seismic dataset to detect mesoscale fractures and the results are confirmed by imaging loggings. Thus, synthetic seismograms, rock physics analysis and field seismic application demonstrates that anisotropic attenuation is the most effective method to detect mesoscale fractures in wide azimuth 3D P-wave seismic data.

  8. Variation of P-wave velocity before the Bear Valley, California, earthquake of 24 February 1972

    USGS Publications Warehouse

    Robinson, R.; Wesson, R.L.; Ellsworth, W.L.

    1974-01-01

    Residuals for P-wave traveltimes at a seismograph station near Bear Valley, California, for small, precisely located local earthquakes at distances of 20 to 70 kilometers show a sharp increase of nearly 0.3 second about 2 months before a magnitude 5.0 earthquake that occurred within a few kilometers of the station. This indicates that velocity changes observed elsewhere premonitory to earthquakes, possibly related to dilatancy, occur along the central section of the San Andreas fault system.

  9. Variation of P-Wave Velocity before the Bear Valley, California, Earthquake of 24 February 1972.

    PubMed

    Robinson, R; Wesson, R L; Ellsworth, W L

    1974-06-21

    Residuals for P-wave traveltimes at a seismnograph station near Bear Valley, California, for small, precisely located local earthquakes at distances of 20 to 70 kilometers show a sharp increase of nearly 0.3 second about 2 months before a magnitude 5.0 earthquake that occurred within a few kilometers of the station. This indicates that velocity changes observed elsewhere premonitory to earthquakes, possibly related to dilatancy, occur along the central section of the San Andreas fault system. PMID:17784227

  10. Testable Signatures of Quantum Nonlocality in a Two-Dimensional Chiral p-Wave Superconductor

    SciTech Connect

    Tewari, Sumanta; Zhang Chuanwei; Das Sarma, S.; Nayak, Chetan; Lee, Dung-Hai

    2008-01-18

    A class of topological excitations--the odd-winding number vortices--in a spinless 2D chiral p-wave (p{sub x}+ip{sub y}) superconductor traps Majorana fermion states in the vortex cores. For a dilute gas of such vortices, the lowest energy fermionic eigenstates are intrinsically nonlocal. We predict two testable signatures of this unusual quantum nonlocality in quasiparticle tunneling experiments. We discuss why the associated teleportationlike phenomenon does not imply the violation of causality.

  11. HFER duration and displacement amplitudes from regional P waves as a possible tsunami earthquake discriminant

    NASA Astrophysics Data System (ADS)

    Hara, T.

    2014-12-01

    Hara (2007) showed that tsunami earthquakes could be characterized by long high frequency energy radiation (HFER) durations and small displacement amplitudes of P-waves in his analysis of tele-seismic data and suggested the possibility to discriminate tsunami earthquakes by measurements of HFER durations and displacement amplitudes. In this study, we investigated this possibility using waveform data recorded in a regional distance range (up to 30 degrees). We used a dataset compiled to develop a formula of Mhdd (Hara, 2013) for regional distance range (Hara, 2014, submitted). It consists of BHZ channel waveform data retrieved from the IRIS Data Management Center for 93 large shallow earthquakes that occurred between 1994 and July, 2013. Two tsunami earthquakes, the July 17, 2006 Java and October 25, 2010 Mentawai, were included. The distance correction for P wave displacements was done simply by a common logarithm of epicentral distance, although a slight different correction is adopted in the Mhdd formula. As was observed in the analysis of tele-seismic data, the tsunami earthquakes were characterized by long HFER durations and small displacement amplitudes measured from P waves. This suggests that it is possible to discriminate tsunami earthquakes by simple measurements of HFER durations and displacement amplitudes from regional P waves more rapidly than those from tele-seismic data. Since some strike slip events have the similar characteristics as tsunami earthquakes in terms of these measurements, rapid focal mechanism determination such as W phase source inversion would be helpful to distinguish tsunami earthquakes from these strike slip events.

  12. P-wave velocity structure of the uppermost mantle beneath Hawaii from traveltime tomography

    USGS Publications Warehouse

    Tilmann, F.J.; Benz, H.M.; Priestley, K.F.; Okubo, P.G.

    2001-01-01

    We examine the P-wave velocity structure beneath the island of Hawaii using P-wave residuals from teleseismic earthquakes recorded by the Hawaiian Volcano Observatory seismic network. The station geometry and distribution of events makes it possible to image the velocity structure between ~ 40 and 100 km depth with a lateral resolution of ~ 15 km and a vertical resolution of ~ 30 km. For depths between 40 and 80 km, P-wave velocities are up to 5 per cent slower in a broad elongated region trending SE-NW that underlies the island between the two lines defined by the volcanic loci. No direct correlation between the magnitude of the lithospheric anomaly and the current level of volcanic activity is apparent, but the slow region is broadened at ~ 19.8??N and narrow beneath Kilauea. In the case of the occanic lithosphere beneath Hawaii, slow seismic velocities are likely to be related to magma transport from the top of the melting zone at the base of the lithosphere to the surface. Thermal modelling shows that the broad elongated low-velocity zone cannot be explained in terms of conductive heating by one primary conduit per volcano but that more complicated melt pathways must exist.

  13. Suppression of surface p-wave superconductivity in disordered topological insulators

    NASA Astrophysics Data System (ADS)

    Tkachov, G.

    2013-06-01

    The paper proposes a self-consistent Green function description of the induced surface superconductivity in a disordered three-dimensional topological insulator (TI) coupled to an s-wave superconductor. We recover earlier results regarding the induced spin-triplet p-wave pairing, showing that a mixture of p- and s-wave pair correlations appears as a result of broken spin-rotation symmetry on the helical surface of the TI. Unlike the s-wave pairing, the p-wave component is found to be suppressed in dirty TIs in which the elastic mean-free path is much smaller than the superconducting coherence length. The suppression is due to the generic nonlocality of the spin-triplet correlations, which makes them strongly dependent on the mean-free path in a disordered system. In dirty TIs the induced superconductivity is predicted to be predominantly s-wave like. In cleaner TIs, however, the p-wave component may reach a magnitude comparable to (but not larger than) the s-wave pairing.

  14. Multifrequency measurements of core-diffracted P waves (Pdiff) for global waveform tomography

    NASA Astrophysics Data System (ADS)

    Hosseini, Kasra; Sigloch, Karin

    2015-10-01

    The lower third of the mantle is sampled extensively by body waves that diffract around the earth's core (Pdiff and Sdiff phases), which could deliver highly resolved tomographic images of this poorly understood region. But core-diffracted waves-especially Pdiff waves-are not often used in tomography because they are difficult to model adequately. Our aim is to make core-diffracted body waves usable for global waveform tomography, across their entire frequency range. Here we present the data processing part of this effort. A method is demonstrated that routinely calculates finite-frequency traveltimes of Pdiff waves by cross-correlating large quantities of waveform data with synthetic seismograms, in frequency passbands ranging from 30.0 to 2.7 s dominant period. Green's functions for 1857 earthquakes, typically comprising thousands of seismograms, are calculated by theoretically exact wave propagation through a spherically symmetric earth model, up to 1 Hz dominant period. Out of 418 226 candidates, 165 651 (39.6 per cent) source-receiver pairs yielded at least one successful passband measurement of a Pdiff traveltime anomaly, for a total of 479 559 traveltimes in the eight passbands considered. Measurements of teleseismic P waves yielded 448 178 usable source-receiver paths from 613 057 candidates (73.1 per cent success rate), for a total of 2 306 755 usable teleseismic dT in eight passbands. Observed and predicted characteristics of Pdiff traveltimes are discussed and compared to teleseismic P for this very large data set. Pdiff measurements are noise-limited due to severe wave attenuation with epicentral distance and frequency. Measurement success drops from 40-60 per cent at 80° distance, to 5-10 per cent at 140°. Frequency has a 2-3 times stronger influence on measurement success for Pdiff than for P. The fewest usable dT measurements are obtained in the microseismic noise band, whereas the fewest usable teleseismic P measurements occur at the highest frequencies. dT anomalies are larger for Pdiff than for P, and frequency dependence of dT due to 3-D heterogeneity (rather than just diffraction) is larger for Pdiff as well. Projecting the Pdiff traveltime anomalies on their core-grazing segments, we retrieve well-known, large-scale structural heterogeneities of the lowermost mantle, such as the two Large Low Shear Velocity Provinces, an Ultra-Low Velocity Zone west of Hawaii, and subducted slab accumulations under East Asia and Central America.

  15. P wave velocity of the uppermost mantle of the Rio Grande rift region of North Central New Mexico

    SciTech Connect

    Murdock, J.N.; Jaksha, L.H.

    1981-08-10

    A network of seismograph stations has operated in north-central New Mexico since 1975. The network is approximtely 200 by 300 km in size and encompasses the Rio Grande rift there. Several seismic refraction experiments have been reported in the literature for the region of the network and adjacent areas. Because all of the seismic refraction lines are unreversed, P/sub n/ velocities reported were mainly of the inverse travel time slope for the direction of the corresponding line. The values of the inverse slope for those studies range from 7.6 to 8.2 km/s. The purpose of our study is to estimate the P wave velocity of the uppermost mantle by using the time term method. First, we timed the P/sub n/ waves of strong signals from five explosions and eight shallow earthquakes recorded by the network. The main data set, which contains 87 time-distance pairs, was processed by using the time term method. The P/sub n/ velocity estimated by this method is 8.0 +- 0.1 km/s. To corroborate this estimate, we then processed 10 subsets of the main data set in the same way. Almost allof the solutions show velocities 7.9--8.1 km/s, in agreement with the velocity determined for the main data set. The station time terms of the main data set also are substantied, and they suggest that the base of the crust dips northward by a few degrees in the region of the survey. The smallest value reported by other investigators for the inverse slope (7.6 km/s) appears to be related to the dip. The normal P wave velocity of the uppermost mantle of north-central New Mexico places restrictions on thermal models of the rift. For instance, the results exlude the likelihood of a wide zone of asthenosphere at the base of the crust beneath the rift, but they do not exclude a narrow such zone.

  16. 19 CFR 122.31 - Notice of arrival.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...22 of this part. (ii) Aircraft arriving from Cuba. Aircraft arriving from Cuba must follow the advance notice of arrival procedures...from areas south of the United States (other than Cuba) must follow the advance notice of arrival...

  17. 19 CFR 122.31 - Notice of arrival.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...22 of this part. (ii) Aircraft arriving from Cuba. Aircraft arriving from Cuba must follow the advance notice of arrival procedures...from areas south of the United States (other than Cuba) must follow the advance notice of arrival...

  18. 19 CFR 122.31 - Notice of arrival.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...22 of this part. (ii) Aircraft arriving from Cuba. Aircraft arriving from Cuba must follow the advance notice of arrival procedures...from areas south of the United States (other than Cuba) must follow the advance notice of arrival...

  19. 19 CFR 122.31 - Notice of arrival.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...22 of this part. (ii) Aircraft arriving from Cuba. Aircraft arriving from Cuba must follow the advance notice of arrival procedures...from areas south of the United States (other than Cuba) must follow the advance notice of arrival...

  20. 19 CFR 122.31 - Notice of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...22 of this part. (ii) Aircraft arriving from Cuba. Aircraft arriving from Cuba must follow the advance notice of arrival procedures...from areas south of the United States (other than Cuba) must follow the advance notice of arrival...

  1. Teleseismic travel times, the Isabella anomaly, and the missing Moho, from the Sierra Nevada EarthScope experiment

    NASA Astrophysics Data System (ADS)

    Thomas, A.; Jones, C.; Reeg, H.; Gilbert, H.; Zandt, G.; Owens, T.

    2005-12-01

    Seismic studies of the southern and central Sierra Nevada revealed a region within the western foothills where the teleseismic P to S Moho conversion is very weak or absent (Zandt et al., Nature, 2004; Burdick et al., this meeting). The conversion could be destroyed by a downward pointing cusp on the Moho produced as crust is entrained in the foundering of the garnet-rich Sierran lower crustal root. The first phase of the recently deployed Sierra Nevada Earthscope Project (SNEP) consists of an array of over 40 broadband seismometers spanning the central Sierra Nevada for a ~15-month period. Initial examination of the new teleseismic travel times from the SNEP stations reveal earlier P-wave arrivals above the "missing" Moho than in the surrounding area. These P-arrivals appear to be inconsistent with the concept of the downward cusp on the Moho: if there were a thicker crust where the Moho is "missing" then the P-wave arrivals in that area should be later than in surrounding areas. P-wave residuals, some of which are more than a second early, indicate that a subsurface high wavespeed body is instead present; these residuals are in part due to the previously described "Isabella anomaly" under the southwestern Sierra. By evaluating the P-wave arrival times from 30 different teleseisms to the SNEP,1997 Sierran Paradox, and 1988 Southern Sierra experiments, we can approximate the spatial geometry of the body or bodies as an elongated body plunging toward the southeast. A preliminary cross section of teleseismic P-residuals using events from the northwest and southeast suggests that the anomaly extends from less than 30 km to as much as 250 km depth. Quite possibly two anomalies exist: one near the Moho in the northwest and one closer to 200 km depth to the southeast. The shallow level of the upper, northwestern end of the body suggests that the "Moho hole" might instead reflect a region where high-wavespeed material exists in the crust, diminishing the contrast at the Moho and thus disrupting the Ps conversion, or that high-wavespeed material overwhelms the effect of thickened crust in this area. The lower bound on the bottom of the Isabella anomaly suggests that the entire foundering body remains in the uppermost mantle and that completed imaging from the combined 1988, 1997, and SNEP experiments will finally complete our picture of this enigmatic body.

  2. Mission Specialist Scott Parazynski arrives at KSC

    NASA Technical Reports Server (NTRS)

    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.

  3. Velocity Structure of the Tibetan Lithosphere: Constraints from P-Wave Travel Times of Regional Earthquakes

    E-print Network

    Nowack, Robert L.

    here. 0 2 4 -700 -500 6 8 -2 -600 -400 -300 -200 Distance (km) T-X/8-Tmin S N average pick error 0 2 4 100 300 6 8 -2 200 400 500 600 Distance (km) T-X/8-Tmin S N average pick error 700 0 2 4 200 400 6 8 -2 300 500 600 700 Distance (km) T-X/8-Tmin S N Event L1a Compared with 3D Model average pick error

  4. P-waves from cross-correlation of seismic noise Philippe Roux, Karim G. Sabra, Peter Gerstoft, and W. A. Kuperman

    E-print Network

    Gerstoft, Peter

    P-waves from cross-correlation of seismic noise Philippe Roux, Karim G. Sabra, Peter Gerstoft. Kuperman, and M. C. Fehler (2005), P-waves from cross- correlation of seismic noise, Geophys. Res. Lett Processing and Experimental Results [5] To demonstrate that P-waves can be extracted from seismic noise data

  5. P wave material anisotropy of a tectono-metamorphic terrane: An active source seismic experiment at the KTB super-deep

    E-print Network

    Okaya, David

    P wave material anisotropy of a tectono-metamorphic terrane: An active source seismic experiment deep drill hole in southeast Germany reveals seismic P wave anisotropy to exist within a tectono. Hasenclever (2004), P wave material anisotropy of a tectono-metamorphic terrane: An active source seismic

  6. Anchorage Arrival Scheduling Under Off-Nominal Weather Conditions

    NASA Technical Reports Server (NTRS)

    Grabbe, Shon; Chan, William N.; Mukherjee, Avijit

    2012-01-01

    Weather can cause flight diversions, passenger delays, additional fuel consumption and schedule disruptions at any high volume airport. The impacts are particularly acute at the Ted Stevens Anchorage International Airport in Anchorage, Alaska due to its importance as a major international portal. To minimize the impacts due to weather, a multi-stage scheduling process is employed that is iteratively executed, as updated aircraft demand and/or airport capacity data become available. The strategic scheduling algorithm assigns speed adjustments for flights that originate outside of Anchorage Center to achieve the proper demand and capacity balance. Similarly, an internal departure-scheduling algorithm assigns ground holds for pre-departure flights that originate from within Anchorage Center. Tactical flight controls in the form of airborne holding are employed to reactively account for system uncertainties. Real-world scenarios that were derived from the January 16, 2012 Anchorage visibility observations and the January 12, 2012 Anchorage arrival schedule were used to test the initial implementation of the scheduling algorithm in fast-time simulation experiments. Although over 90% of the flights in the scenarios arrived at Anchorage without requiring any delay, pre-departure scheduling was the dominant form of control for Anchorage arrivals. Additionally, tactical scheduling was used extensively in conjunction with the pre-departure scheduling to reactively compensate for uncertainties in the arrival demand. For long-haul flights, the strategic scheduling algorithm performed best when the scheduling horizon was greater than 1,000 nmi. With these long scheduling horizons, it was possible to absorb between ten and 12 minutes of delay through speed control alone. Unfortunately, the use of tactical scheduling, which resulted in airborne holding, was found to increase as the strategic scheduling horizon increased because of the additional uncertainty in the arrival times of the aircraft. Findings from these initial experiments indicate that it is possible to schedule arrivals into Anchorage with minimal delays under low-visibility conditions with less disruption to high-cost, international flights.

  7. Decays, contact P-wave interactions and hyperfine structure in Omega- exotic atoms

    E-print Network

    M. I. Krivoruchenko; Amand Faessler

    2008-04-05

    Contact $P$-wave interactions connected to the Larmor interaction of a magnetic dipole and Thomas spin precession in the filed of an electric quadrupole are described and their implications for spectroscopy of exotic $\\Omega^{-}$-atoms are studied. In order to evaluate the magnitude of the contact $P$-wave interactions as compared to the conventional long-range interactions and the sensitivity of spectroscopic data to the $\\Omega^{-}$-hyperon quadrupole moment, we consider $2P$ states of $\\Omega ^{-}$ atoms formed with light stable nuclei with spins $I \\geq 1/2$ and atomic numbers $Z \\leq 10$. The energy level splitting caused by the contact interactions is 2-5 orders of magnitude smaller than the conventional long-range interactions. Strong decay widths of $p\\Omega ^{-}$ atoms due to reactions $p\\Omega^{-} \\to \\Lambda \\Xi^{0}$ and $p\\Omega^{-} \\to \\Sigma \\Xi$, induced by $t$-channel kaon exchanges, are calculated. $\\Omega ^{-}$ atoms formed with the light nuclei have strong widths 5-6 orders of magnitude higher than splitting caused by the contact interactions. The low-$L$ pattern in the energy spectra of intermediate- and high-$Z$ $\\Omega ^{-}$ atoms thus cannot be observed. The $\\Omega ^{-}$ quadrupole moment can be measured by observing $X$-rays from circular transitions between high-$L$ levels in $\\Omega^{-}$ exotic atoms. The effect of strong interactions in $^{208}$Pb$\\Omega ^{-}$ atoms is negligible starting from $L \\sim 10$. The contact $P$-wave interactions exist in ordinary atoms and $\\mu$-meson atoms.

  8. Spin-polarization transport in ferromagnetic semiconductor/ferromagnetic p-wave superconductor junctions

    NASA Astrophysics Data System (ADS)

    Li, Hong; Yang, Xinjian; Chen, Wenjuan

    2010-05-01

    An extended Blonder-Tinkham-Klapwijk (BTK) approach is applied to study the spin polarized transport in ferromagnetic semiconductor/ferromagnetic p-wave superconductor ( FS/FpS) junctions. It is demonstrated that the normalization conductance strongly depends not only on the kinds of holes (heavy or light) in the FS and pairings for the FpS but also on the relative orientations of the effective exchange field in the FS and FpS. In triplet superconductor junctions zero-energy Andreev bound states (ABS) and proximity effect can coexist with each other. This property may serve as a method to identify the triplet symmetry of ferromagnetic superconductors.

  9. Effective field theory for a p -wave superconductor in the subgap regime

    NASA Astrophysics Data System (ADS)

    Hansson, T. H.; Kvorning, T.; Nair, V. P.; Sreejith, G. J.

    2015-02-01

    We construct an effective field theory for the 2 d spinless p -wave paired superconductor that faithfully describes the topological properties of the bulk state, and also provides a model for the subgap states at vortex cores and edges. In particular, it captures the topologically protected zero modes and has the correct ground-state degeneracy on the torus. We also show that our effective field theory becomes a topological field theory in a well defined scaling limit and that the vortices have the expected non-Abelian braiding statistics.

  10. Pion-nucleon scattering in the Skyrme model and the P-wave Born amplitudes

    NASA Astrophysics Data System (ADS)

    Hayashi, A.; Saito, S.; Uehara, M.

    1991-03-01

    We treat fluctuating pion fields around a rotating Skyrmion by means of Dirac's quantization method. The rotational collective motion of the Skyrmion is described by collective coordinates, and conventional gauge-fixing conditions are imposed. Taking into account all the relevant terms at the tree level appearing in the Hamiltonian, we show that pion-nucleon scattering amplitudes exhibit the P-wave Born amplitudes attributed to the Yukawa coupling of order ?Nc , which is consistent with the prediction of chiral symmetry such as the Adler-Weisberger relation. This resolves the difficulty that the Skyrme model predicts a wrong Nc dependence for the coupling of order N-3/2c.

  11. A Split of Direction of Propagation and Attenuation of P Waves in the Po Valley

    NASA Astrophysics Data System (ADS)

    Daminelli, R.; Tento, A.; Marcellini, A.

    2013-12-01

    On July 17, 2011 a ML 4.8 earthquake occurred in the PO valley at a 48 km epicentral distance from a seismic station located at Palazzo Te (Mantova). The station is situated on deep quaternary sediments: the uppermost layers are mainly composed of clay and silty clay with interbedded sands; the Robertson index is 1.4P wave particle motion, that appears rather difficult to explain if we assume the homogeneity of the P waves (that means attenuation is scalar). Note that the degree of nonlinearity is very low given that the maximum strain can be roughly estimated as 10-5 on the basis of maximum ground velocity of the P wave train considered and the Vp. On the contrary we show that P wave particle motion can be fully (and easily) described by a Homogeneous Isotropic Linear Viscoelastic model (HILV). HILV, as in the 2009 Borcherdt formulation adopted here, allows two different directions of propagation and attenuation; in other words attenuation becomes a vector that is not necessarily parallel to the propagation vector. The results evidence that the incidence angle and the inhomogeneity angle (it is the angle between propagation and attenuation vectors and it is closely related to Q factor) are in good agreement with the geological conditions of the site. Finally, we observed that these results are very similar to the ones obtained when we analyzed two explosions recorded by a seismic station in Milano, also situated in the Po valley at some 140 km from Mantova (Marcellini & Tento, 2011). Borcherdt, R.D. (2009) 'Viscoelastic Waves in Layered Media', Cambridge University Press, Cambridge, United Kingdom, 305 pp. Marcellini, A. and A. Tento (2011) ' Explosive Sources Prove the Validity of Homogeneous Isotropic Linear Viscoelastic Models', BSSA, Vol. 101, No. 4, pp. 1576-1583.

  12. Condensates of p-wave pairs are exact solutions for rotating two-component Bose gases.

    PubMed

    Papenbrock, T; Reimann, S M; Kavoulakis, G M

    2012-02-17

    We derive exact analytical results for the wave functions and energies of harmonically trapped two-component Bose-Einstein condensates with weakly repulsive interactions under rotation. The isospin symmetric wave functions are universal and do not depend on the matrix elements of the two-body interaction. The comparison with the results from numerical diagonalization shows that the ground state and low-lying excitations consist of condensates of p-wave pairs for repulsive contact interactions, Coulomb interactions, and the repulsive interactions between aligned dipoles. PMID:22401222

  13. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2010 CFR

    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...

  14. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 8 Aliens and Nationality 1 2014-01-01 2014-01-01 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...

  15. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 8 Aliens and Nationality 1 2011-01-01 2011-01-01 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...

  16. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 8 Aliens and Nationality 1 2012-01-01 2012-01-01 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...

  17. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 8 Aliens and Nationality 1 2013-01-01 2013-01-01 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...

  18. High-resolution 3-D P-wave tomographic imaging of the shallow magmatic system of Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Zandomeneghi, D.; Aster, R. C.; Barclay, A. H.; Chaput, J. A.; Kyle, P. R.

    2011-12-01

    Erebus volcano (Ross Island), the most active volcano in Antarctica, is characterized by a persistent phonolitic lava lake at its summit and a wide range of seismic signals associated with its underlying long-lived magmatic system. The magmatic structure in a 3 by 3 km area around the summit has been imaged using high-quality data from a seismic tomographic experiment carried out during the 2008-2009 austral field season (Zandomeneghi et al., 2010). An array of 78 short period, 14 broadband, and 4 permanent Mount Erebus Volcano Observatory seismic stations and a program of 12 shots were used to model the velocity structure in the uppermost kilometer over the volcano conduit. P-wave travel times were inverted for the 3-D velocity structure using the shortest-time ray tracing (50-m grid spacing) and LSQR inversion (100-m node spacing) of a tomography code (Toomey et al., 1994) that allows for the inclusion of topography. Regularization is controlled by damping and smoothing weights and smoothing lengths, and addresses complications that are inherent in a strongly heterogeneous medium featuring rough topography and a dense parameterization and distribution of receivers/sources. The tomography reveals a composite distribution of very high and low P-wave velocity anomalies (i.e., exceeding 20% in some regions), indicating a complex sub-lava-lake magmatic geometry immediately beneath the summit region and in surrounding areas, as well as the presence of significant high velocity shallow regions. The strongest and broadest low velocity zone is located W-NW of the crater rim, indicating the presence of an off-axis shallow magma body. This feature spatially corresponds to the inferred centroid source of VLP signals associated with Strombolian eruptions and lava lake refill (Aster et al., 2008). Other resolved structures correlate with the Side Crater and with lineaments of ice cave thermal anomalies extending NE and SW of the rim. High velocities in the summit area possibly constitute the seismic image of an older caldera, solidified intrusions or massive lava flows. REFERENCES: Aster et al., (2008) Moment tensor inversion of very long period seismic signals from Strombolian eruptions of Erebus volcano. J. Volcanol. Geotherm. Res., 177, 635-647. Toomey et al., (1994), Tomographic imaging of the shallow crustal structure of the East Pacific Rise at 9°30'N. J. Geophys. Res., 99 (B12), 24,135-24,157. Zandomeneghi et al., (2010), Seismic Tomography of Erebus Volcano, Antarctica, Eos, 91, 6, 53-55.

  19. Collective modes of p-wave superfluid Fermi gases in BEC phase

    E-print Network

    Francesco Matera; Matthias F. Wagner

    2015-06-08

    The low-energy modes of a superfluid atomic Fermi gas at zero temperature are investigated. The Bose-Einstein-condensate (BEC) side of the superfluid phase is studied in detail. The atoms are assumed to be in only one internal state, so that for a sufficiently diluted gas the pairing of fermions can be considered effective in the l=1 channel only. In agreement with previous works on p-wave superfluidity in Fermi systems, it is found that the $p_x+ip_y$ phase represents the lowest energy state in both the Bardeen-Cooper-Schrieffer (BCS) and BEC sides. Our calculations show that at low energy three branches of collective modes can emerge, with different species of dispersion relations: a phonon-like mode, a single-particle-like mode and a gapped mode. A comparison with the Bogoliubov excitations of the corresponding spinor Bose condensate is made. They reproduce the dispersion relations of the excitation modes of the p-wave superfluid Fermi gas to a high accuracy.

  20. Seismic effects of incident P waves on an embedded foundation in poroelastic half-space

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Cai, Yuan-qiang; Ding, Guang-ya; Wang, Li-zhong

    2012-03-01

    Dynamic vibrations of a circular rigid foundation, which is embedded in poroelastic soil and subjected to incident P waves, are studied by semi-analytical methods in this present work. The motion of the soil is governed by Biot's dynamic poroelastic theory. A set of potentials are introduced to represent the incident waves, and the scattering waves caused by the foundation are considered based on the decomposition of the total wave field in soil. The soil along the vertical side of the foundation is assumed to be composed of series of infinitesimally thin poroelastic layers, while the soil under the foundation base is regarded as the poroelastic half-space and to be independent of the overlying soil. The interaction problem is solved by Hankel transforms. Then, combining the boundary conditions along the contact surface between the soil and the foundation and the dynamic equilibrium equation of the foundation, expressions of the vertical and rocking vibration amplitudes of the embedded foundation excited by the incident P waves are acquired. Numerical results are presented to demonstrate the influences of embedded depth, foundation mass, pore water in the soil and incident angle on the vibrations of the foundation.

  1. Holographic model of hybrid and coexisting s-wave and p-wave Josephson junction

    NASA Astrophysics Data System (ADS)

    Liu, Shuai; Wang, Yong-Qiang

    2015-10-01

    In this paper the holographic model for a hybrid and coexisting s-wave and p-wave Josephson junction is constructed by a triplet charged scalar field coupled with a non-Abelian SU(2) gauge field in (3+1)-dimensional AdS spacetime. Depending on the value of chemical potential ? one can show that there are four types of junctions (s+p-N-s+p, s+p-N-s, s+p-N-p and s-N-p). We show that the DC currents of all the hybrid and coexisting s-wave and p-wave junctions are proportional to the sine of the phase difference across the junction. In addition, the maximum current and the total condensation decay with the width of junction exponentially, respectively. For the s+p-N-s and s-N-p junctions, the maximum current decreases with growing temperature. Moreover, we find that the maximum current increases with growing temperature for the s+p-N-s+p and s+p-N-p junctions, which is different from the behavior of the s+p-N-s and s-N-p junctions.

  2. A QCD sum rule calculation for P-wave bottom baryons

    E-print Network

    Mao, Qiang; Chen, Wei; Hosaka, Atsushi; Liu, Xiang; Zhu, Shi-Lin

    2015-01-01

    We study the P-wave bottom baryons using the method of QCD sum rule and heavy quark effective theory. Our results suggest that Lambda_b(5912) and Lambda_b(5920) can be well described by the baryon doublet [3F_bar, 1, 1, rho], and they belong to the SU(3) 3F_bar multiplets of J(P)=1/2(-) and 3/2(-). Their SU(3) flavor partners, Xi_b(1/2-) and Xi_b(3/2-), have masses 6.06 \\pm 0.13 GeV and 6.07 \\pm 0.13 GeV, respectively, with mass splitting 9 \\pm 4 MeV. The results obtained using baryon doublet [3F_bar, 1, 0, lambda] are similar and also consistent with the experimental data. We also study the SU(3) 6F multiplets by using the baryon multiplets [6F, 0, 1, lambda], [6_F, 1, 0, rho] and [6F, 2, 1, lambda], and our results suggest that the $P$-wave bottom baryons Sigma_b, Xi'_b and Omega_b have (averaged) masses about 6.0 GeV, 6.2 GeV and 6.4 GeV, respectively.

  3. Detailed rupture imaging of the 25 April 2015 Nepal earthquake using teleseismic P waves

    NASA Astrophysics Data System (ADS)

    Fan, Wenyuan; Shearer, Peter M.

    2015-07-01

    We analyze the rupture process of the 25 April 2015 Nepal earthquake with globally recorded teleseismic P waves. The rupture propagated east-southeast from the hypocenter for about 160 km with a duration of ˜55 s. Backprojection of both high-frequency (HF, 0.2 to 3 Hz) and low-frequency (LF, 0.05 to 0.2 Hz) P waves suggest a multistage rupture process. From the low-frequency images, we resolve an initial slow downdip (northward) rupture near the nucleation area for the first 20 s (Stage 1), followed by two faster updip ruptures (20 to 40 s for Stage 2 and 40 to 55 s for Stage 3), which released most of the radiated energy northeast of Kathmandu. The centroid rupture power from LF backprojection agrees well with the Global Centroid Moment Tensor solution. The spatial resolution of the backprojection images is validated by applying similar analysis to nearby aftershocks. The overall rupture pattern agrees well with the aftershock distribution. A multiple-asperity model could explain the observed multistage rupture and aftershock distribution.

  4. Preliminary Results for Crustal Structure in Southeastern Africa from P-wave Receiver Functions

    NASA Astrophysics Data System (ADS)

    Kachingwe, M.; Nyblade, A.; Mulibo, G.; Mulowezi, A.; Kunkuta, E.; De Magalhães, V.; Wysession, M. E.; Wiens, D. A.; Julia, J.

    2012-12-01

    The crustal structure of southeastern Africa is investigated by modeling P-wave receiver functions using H-k stacking and joint inversion methods. P-wave receiver functions are analyzed for 29 broadband seismic stations in Zambia, Malawi and Mozambique. Estimates for the Moho depth and Poisson's ratio are determined from H-k stacking, and estimates for the shear wave velocity are determined by the joint inversion of receiver functions and surface wave dispersion. Preliminary results show that Moho depths beneath southeastern Africa range from 32 km to 51 km. Thicker crust is found in Proterozoic terrains, such as the Irumide Belt, while thinner crust is found in reworked Archean terrains, such as the Bangweulu Block. These results are consistent with previous studies and global averages for Precambrian terrains. The preliminary results also show a range of Poisson's ratios from 0.2 to 0.3. These new results for southeastern Africa are being combined with similar results from elsewhere in eastern and southern Africa to improve our understanding of African crustal structure.

  5. Preliminary Results for Crustal Structure in Southeastern Africa from P-wave Receiver Functions

    NASA Astrophysics Data System (ADS)

    Kachingwe, M.; Nyblade, A.; Mulibo, G. D.; Mulowezi, A.; Kunkuta, E.; De Magalhães, V.; Wiens, D. A.; Wysession, M. E.; Julia, J.

    2013-12-01

    The crustal structure of southeastern Africa is investigated by modeling P-wave receiver functions using H-k stacking and joint inversion methods. P-wave receiver functions are analyzed for 29 broadband seismic stations in Zambia, Malawi and Mozambique. Estimates for the Moho depth and Poisson's ratio are determined from H-k stacking, and estimates for the shear wave velocity are determined by the joint inversion of receiver functions and surface wave dispersion. Preliminary results show that Moho depths beneath southeastern Africa range from 32 km to 51 km. Thicker crust is found in Proterozoic terrains, such as the Irumide Belt, while thinner crust is found in reworked Archean terrains, such as the Bangweulu Block. These results are consistent with previous studies and global averages for Precambrian terrains. The preliminary results also show a range of Poisson's ratios from 0.2 to 0.3. These new results for southeastern Africa are being combined with similar results from elsewhere in eastern and southern Africa to improve our understanding of African crustal structure.

  6. Application of P-wave Hybrid Theory to the Scattering of Electrons from He+ and Resonances in He and H ion

    NASA Technical Reports Server (NTRS)

    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.

  7. Crustal P-wave velocity structure from Altyn Tagh to Longmen mountains along the Taiwan-Altay geoscience transect

    USGS Publications Warehouse

    Wang, Y.-X.; Mooney, W.D.; Han, G.-H.; Yuan, X.-C.; Jiang, M.

    2005-01-01

    Based upon the seismic experiments along Geoscience Transect from the Altyn Tagh to the Longmen Mountains, the crustal P-wave velocity structure was derived to outline the characteristics of the crustal structure. The section shows a few significant features. The crustal thickness varies dramatically, and is consistent with tectonic settings. The Moho boundary abruptly drops to 73km depth beneath the southern Altyn Tagh from 50km below the Tarim basin, then rises again to about 58km depth beneath the Qaidam basin. Finally, the Moho drops again to about 70km underneath the Songpan-Garze Terrane and rises to 60km near the Longmen Mountains with a step-shape. Further southeast, the crust thins to 52km beneath the Sichuan basin in the southeast of the Longmen Mountains. In the north of the Kunlun fault, a low-velocity zone, which may be a layer of melted rocks due to high temperature and pressure at depth, exists in the the bottom of the middle crust. The two depressions of the Moho correlate with the Qilian and Songpan-Garze terranes, implying that these two mountains have thick roots. According to our results, it is deduced that the thick crust of the northeastern Tibetan Plateau probably is a result of east-west and northwest-southeast crustal shortening since Mesozoic time during the collision between the Asian and Indian plates.

  8. Dependence of P-wave dispersion on mean arterial pressure as an independent hemodynamic variable in school children

    PubMed Central

    González, Emilio F.; Llanes, María del Carmen; Llanes, Merlin Garí; García, Yosvany

    2013-01-01

    Introduction: The relationship between diastolic dysfunction and P-wave dispersion (PWD) in the electrocardiogram has been studied for some time. In this regard, echocardiography is emerging as a diagnostic tool to improve risk stratification for mild hypertension. Objective: To determine the dependence of PWD on the electrocardiogram and on echocardiographic variables in a pediatric population. Methods: 515 children from three elementary schools were studied from a total of 565 children. Those whose parents did not want them to take part in the study, as well as those with known congenital diseases, were excluded. Tests including 12-lead surface ECGs and 4 blood pressure (BP) measurements were performed. Maximum and minimum P-values were measured, and the PWD on the electrocardiogram was calculated. Echocardiography for structural measurements and the pulsed Doppler of mitral flow were also performed. Results: A significant correlation in statistical variables was found between PWD and mean BP for pre-hypertensive and hypertensive children, i.e., r = 0.32, p <0.01 and r = 0.33, p <0.01, respectively. There was a significant correlation found between PWD and the left atrial area (r = 0.45 and p <0.01). Conclusions: We highlight the dependency between PWD, the electrocardiogram and mean blood pressure. We also draw attention to the dependence of PWD on the duration of the mitral inflow A-wave. This result provides an explanation for earlier changes in atrial electrophysiological and hemodynamic characteristics in pediatric patients. PMID:24892616

  9. Improvement to Airport Throughput Using Intelligent Arrival Scheduling and an Expanded Planning Horizon

    NASA Technical Reports Server (NTRS)

    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.

  10. 19 CFR 122.31 - Notice of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... advance notice of arrival in accordance with § 122.22 of this part. (ii) Aircraft arriving from Cuba. Aircraft arriving from Cuba must follow the advance notice of arrival procedures set forth in § 122.154 in... aircraft arriving from areas south of the United States (other than Cuba) must follow the advance notice...

  11. Does Pet Arrival Trigger Prosocial Behaviors in Individuals with Autism?

    PubMed Central

    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 (t0) and time of assessment (t1) 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. PMID:22870246

  12. Does pet arrival trigger prosocial behaviors in individuals with autism?

    PubMed

    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. PMID:22870246

  13. P-wave superfluid in a quasi-two-dimensional dipolar Bose-Fermi quantum gas mixture

    NASA Astrophysics Data System (ADS)

    Kain, Ben; Ling, Hong

    2013-03-01

    The p-wave (px + ipy) superfluid has attracted significant attention in recent years mainly because its vortex core supports a Majorana fermion which, due to its non-Abelian statistics, can be explored for implementing topological quantum computation (TQC). Mixing in bosons may lead to p-wave pairing in a Fermi gas. In a dipolar condensate, the dipole-dipole interaction represents a control knob inaccessible to nondipolar Bosons. Thus, mixing dipolar bosons with fermions opens up new possibilities. We consider a mixture of a spin-polarized Fermi gas and a dipolar Bose-Einstein condensate in a quasi-two-dimensional trap setting. We take the Hartree-Fock-Bogoliubov mean-field approach and develop a theory for studying the stability of the mixture and estimating the critical temperature of the p-wave superfluid. We use this theory to identify the experimentally accessible parameter space in which the mixture is stable against phase separation and the p-wave superfluid pairing can be resonantly enhanced. An enhanced p-wave superfluid order parameter can make the fault tolerant TQC less susceptible to thermal fluctuations. This work aims to stimulate experimental activity in creating dipolar Bose-Fermi mixtures. This work is supported by the US National Science Foundation and the US Army Research Office

  14. 14 CFR 93.23 - Arrival Authorizations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction at Chicago O'Hare International Airport § 93.23 Arrival Authorizations. (a) Except as otherwise established by the...

  15. 14 CFR 93.23 - Arrival Authorizations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction at Chicago O'Hare International Airport § 93.23 Arrival Authorizations. (a) Except as otherwise established by the...

  16. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    8 Aliens and Nationality 1 2012-01-01 2012-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL...

  17. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    8 Aliens and Nationality 1 2011-01-01 2011-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL...

  18. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2010 CFR

    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...

  19. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    8 Aliens and Nationality 1 2014-01-01 2014-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL...

  20. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    8 Aliens and Nationality 1 2013-01-01 2013-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL...

  1. Prediction of Building Limestone Physical and Mechanical Properties by Means of Ultrasonic P-Wave Velocity

    PubMed Central

    Concu, Giovanna; De Nicolo, Barbara; Valdes, Monica

    2014-01-01

    The aim of this study was to evaluate ultrasonic P-wave velocity as a feature for predicting some physical and mechanical properties that describe the behavior of local building limestone. To this end, both ultrasonic testing and compressive tests were carried out on several limestone specimens and statistical correlation between ultrasonic velocity and density, compressive strength, and modulus of elasticity was studied. The effectiveness of ultrasonic velocity was evaluated by regression, with the aim of observing the coefficient of determination r2 between ultrasonic velocity and the aforementioned parameters, and the mathematical expressions of the correlations were found and discussed. The strong relations that were established between ultrasonic velocity and limestone properties indicate that these parameters can be reasonably estimated by means of this nondestructive parameter. This may be of great value in a preliminary phase of the diagnosis and inspection of stone masonry conditions, especially when the possibility of sampling material cores is reduced. PMID:24511286

  2. Spin polarization and Zeeman effects in ferromagnet/ferromagnetic p-wave superconductor junctions

    NASA Astrophysics Data System (ADS)

    Li, Hong; Yang, Xinjian

    2011-01-01

    An extended Blonder-Tinkham-Klapwijk (BTK) approach is applied to study the spin polarization and Zeeman effects in ferromagnet/ferromagnetic p-wave superconductor ( FM/FpS) junctions. Three kinds of pairings for F pS are chosen: px,py,px+ipy waves. It is found that the normalized conductance strongly depends on both kinds of pairings and the relative orientations of the effective exchange field in the FM and FpS. In triplet superconductor junctions the multiplication of zero-energy Andreev bound states (ABSs) with the Zeeman effect induces an additional peak splitting. This property may serve as a method to identify triplet symmetry of ferromagnetic superconductors.

  3. Tunneling conductance in topological insulator ferromagnet/p-wave superconductor junctions

    NASA Astrophysics Data System (ADS)

    Li, Hong; Yang, Xinjian

    2012-09-01

    The tunneling conductance in topological insulator (TI) ferromagnet/p-wave superconductor (FM/pS) junction is studied based on the Blonder-Tinkham-Klapwijk (BTK) theory. The Fermi energy mismatch between FM and pS as well as the finite quasiparticle lifetime are considered. Three kinds of pairings px, py, and px+ipy-waves for pS are chosen. It is found that the spectrum strongly depend on the magnetic gap, the gate potential, the quasiparticle lifetime as well as the type of the pair potential symmetry. The pair potential symmetry drastically affects the formation of the zero-energy bound states dependent on the magneto effect or the Fermi energy mismatch effect. The finite quasiparticle lifetime effect can suppress the Andreev resonant scattering process at eV=?0 and smear the dips in the conductance.

  4. How do shear wave events affect normal P-wave records

    SciTech Connect

    Ameely, L.; Edelmann, H.A.K.; Fertig, J.

    1985-04-01

    It has been known since the beginning of reflection seismics that several disturbing events seen in seismic records are caused by waves with S-wave velocities instead of P-wave velocity. When using dynamite and recording with vertical geophones these events are primarily caused by converted waves. On the basis of known P- and S-wave velocities Carboniferous strata in the Ruhr area in NW Germany a theoretical seismogram is calculated, displaying traveltime as well as energy relation for different wave configurations. By comparison with seismograms recorded in the same area it can be shown that converted wave events can be clearly recognized. These events can be described theoretically. Thus, either more effective computer programs can be applied to eliminate these disturbing events, or these events can be evaluated to get additional information about specific strata.

  5. Hybrid calculation of P-wave e-Li ion scattering and photoabsorption

    NASA Astrophysics Data System (ADS)

    Bhatia, Anand

    2013-05-01

    A variational wave function incorporating short range correlations via Hylleraas type functions plus long-range polarization terms of the polarized orbital type but with smooth cut-off factors has been used to calculate P-wave phase shifts for electron-Li+2 scattering. This approach gives the direct r-4 potential and a non-local optical potential which is negative definite. The resulting phase shifts have rigorous lower bonds and the convergence is much faster than those obtained without the modification of the target function. The continuum functions obtained in such calculation have been used to calculate photoabsorption cross sections of ground and metastable states in H-, He, and Li+1. These cross sections have been used to calculate recombination rate coefficients. Final results will be presented at the conference.

  6. Multiparticle content of Majorana zero modes in the interacting p -wave wire

    NASA Astrophysics Data System (ADS)

    Kells, G.

    2015-10-01

    In the topological phase of p -wave superconductors, zero-energy Majorana quasiparticle excitations can be well defined in the presence of local density-density interactions. Here, we examine this phenomenon from the perspective of matrix representations of the commutator H =[H ,•] , with the aim of characterizing the multiparticle content of the many-body Majorana mode. To do this we show that, for quadratic fermionic systems, H can always be decomposed into subblocks that act as multiparticle generalizations of the Bogoliubov-de Gennes/Majorana forms that encode single-particle excitations. In this picture, density-density-like interactions will break this exact excitation-number symmetry, coupling different subblocks and lifting degeneracies so that the eigenoperators of the commutator H take the form of individual eigenstate transitions |n >p -wave lattice model. We find that the multiparticle content of the Majorana zero-mode operators is significant even at modest interaction strengths. This has important consequences for the stability of Majorana-based qubits when they are coupled to a heat bath. We will also discuss how these findings differ from previous work regarding the structure of the many-body Majorana operators and point out that this should affect how certain experimental features are interpreted.

  7. P-wave and QT dispersion in patients with conversion disorder

    PubMed Central

    Izci, Filiz; Hocagil, Hilal; Izci, Servet; Izci, Vedat; Koc, Merve Iris; Acar, Rezzan Deniz

    2015-01-01

    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±10 vs 398±12, P<0.001, and 47±4.8 vs 20±6.1, P<0.001, respectively). Conclusion A similar relation to that in literature between QTd and anxiety and somatoform disorders 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. PMID:25848293

  8. SERAPIS project - 3D imaging of the Campi Flegrei caldera (southern Italy) : high resolution P-wave velocity tomography

    NASA Astrophysics Data System (ADS)

    Judenherc, S.; Zollo, A.; Auger, E.; Boschi, L.; Satriano, C.; Serapis Working Group

    2003-04-01

    In September 2001, the SERAPIS project was carried out as an extended active seismic survey in the gulfs of Naples and Pozzuoli. A dense array of 60 three-component on-land stations and 72 sea bottom seismographs (OBS) have been deployed to record more than 5000 air gun shots at a spacing of about 125~m. As a preliminary analysis, the first P-arrival times of a the small offset data in the central part of the region has been inverted using the codes of H.M. Benz. The linearized iterative inversion of 38000 arrival times provided a >80% variance reduction with a node spacing of 250m. At the first order, our model shows a 2-layer structure : low velocity volcanic sediments (2.5-3.5km/s) lying on an inclined high velocity limestone platform (>6km/s). The caldera itself is very well identified, the rim is characterized by a 500-1000m upward shift of the velocity isolines. The whole dataset is expected to provide a wider image with the same resolution (250m). It includes the detailed shape of the refractor beneath the caldera as well as its irregularities out of the bay which have been observered in the seismic sections.

  9. The relationship between gas hydrate saturation and P-wave velocity of pressure cores obtained in the Eastern Nankai Trough

    NASA Astrophysics Data System (ADS)

    Konno, Y.; Yoneda, J.; Jin, Y.; Kida, M.; Suzuki, K.; Nakatsuka, Y.; Fujii, T.; Nagao, J.

    2014-12-01

    P-wave velocity is an important parameter to estimate gas hydrate saturation in sediments. In this study, the relationship between gas hydrate saturation and P-wave velocity have been analyzed using natural hydrate-bearing-sediments obtained in the Eastern Nankai Trough, Japan. The sediment samples were collected by the Hybrid Pressure Coring System developed by Japan Agency for Marine-Earth Science and Technology during June-July 2012, aboard the deep sea drilling vessel CHIKYU. P-wave velocity was measured on board by the Pressure Core Analysis and Transfer System developed by Geotek Ltd. The samples were maintained at a near in-situ pressure condition during coring and measurement. After the measurement, the samples were stored core storage chambers and transported to MHRC under pressure. The samples were manipulated and cut by the Pressure-core Non-destructive Analysis Tools or PNATs developed by MHRC. The cutting sections were determined on the basis of P-wave velocity and visual observations through an acrylic window equipped in the PNATs. The cut samples were depressurized to measure gas volume for saturation calculations. It was found that P-wave velocity correlates well with hydrate saturation and can be reproduced by the hydrate frame component model. Using pressure cores and pressure core analysis technology, nondestructive and near in-situ correlation between gas hydrate saturation and P-wave velocity can be obtained. This study was supported by funding from the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) planned by the Ministry of Economy, Trade and Industry (METI), Japan.

  10. Research Of Airborne Precision Spacing to Improve Airport Arrival Operations

    NASA Technical Reports Server (NTRS)

    Barmore, Bryan E.; Baxley, Brian T.; Murdoch, Jennifer L.

    2011-01-01

    In September 2004, the European Organization for the Safety of Air Navigation (EUROCONTROL) and the United States Federal Aviation Administration (FAA) signed a Memorandum of Cooperation to mutually develop, modify, test, and evaluate systems, procedures, facilities, and devices to meet the need for safe and efficient air navigation and air traffic control in the future. In the United States and Europe, these efforts are defined within the architectures of the Next Generation Air Transportation System (NextGen) Program and Single European Sky Air Traffic Management Research (SESAR) Program respectively. Both programs have identified Airborne Spacing as a critical component, with Automatic Dependent Surveillance Broadcast (ADS-B) as a key enabler. Increased interest in reducing airport community noise and the escalating cost of aviation fuel has led to the use of Continuous Descent Arrival (CDA) procedures to reduce noise, emissions, and fuel usage compared to current procedures. To provide these operational enhancements, arrival flight paths into terminal areas are planned around continuous vertical descents that are closer to an optimum trajectory than those in use today. The profiles are designed to be near-idle descents from cruise altitude to the Final Approach Fix (FAF) and are typically without any level segments. By staying higher and faster than conventional arrivals, CDAs also save flight time for the aircraft operator. The drawback is that the variation of optimized trajectories for different types and weights of aircraft requires the Air Traffic Controller to provide more airspace around an aircraft on a CDA than on a conventional arrival procedure. This additional space decreases the throughput rate of the destination airport. Airborne self-spacing concepts have been developed to increase the throughput at high-demand airports by managing the inter-arrival spacing to be more precise and consistent using on-board guidance. It has been proposed that the additional space needed around an aircraft performing a CDA could be reduced or eliminated when using airborne spacing techniques.

  11. Predicted signatures of p-wave superfluid phases and Majorana zero modes of fermionic atoms in rf absorption

    SciTech Connect

    Grosfeld, Eytan; Stern, Ady; Ilan, Roni; Cooper, Nigel R.

    2007-09-01

    We study the superfluid phases of quasi-two-dimensional atomic Fermi gases interacting via a p-wave Feshbach resonance. We calculate the absorption spectra of these phases under a hyperfine transition for both nonrotating and rotating superfluids. We show that one can identify the different phases of the p-wave superfluid from the absorption spectrum. The absorption spectrum shows clear signatures of the existence of Majorana zero modes at the cores of vortices of the weakly pairing p{sub x}+ip{sub y} phase.

  12. Amplitude and angle of arrival measurements on a 28.56 GHz Earth-space path

    NASA Technical Reports Server (NTRS)

    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.

  13. NASA's SOFIA Arrives in Christchurch, New Zealand, July 14, 2013 - Duration: 101 seconds.

    NASA Video Gallery

    NASA's Stratospheric Observatory for Infrared Astronomy airborne observatory arrived at Christchurch International Airport, New Zealand, July 14 at 12:14 p.m. (New Zealand Standard Time) to investi...

  14. Approximate Analysis of Queueing Networks with Markovian Arrival Processes and Phase Type Service

    E-print Network

    Strelen, Christoph

    networks with Markovian arrival processes and phase type ser­ vice times are considered. A technique is subject to a combinatorial explosion law. Therefore exact methods will never suffice for all models

  15. An Analysis of the Relationship Between the Heat Index and Arrivals in the Emergency Department

    PubMed Central

    Levy, Matthew; Broccoli, Morgan; Cole, Gai; Jenkins, J Lee; Klein, Eili Y.

    2015-01-01

    Background: Heatwaves are one of the most deadly weather-related events in the United States and account for more deaths annually than hurricanes, tornadoes, floods, and earthquakes combined. However, there are few statistically rigorous studies of the effect of heatwaves on emergency department (ED) arrivals. A better understanding of this relationship can help hospitals plan better and provide better care for patients during these types of events. Methods: A retrospective review of all ED patient arrivals that occurred from April 15 through August 15 for the years 2008 through 2013 was performed. Daily patient arrival data were combined with weather data (temperature and humidity) to examine the potential relationships between the heat index and ED arrivals as well as the length of time patients spend in the ED using generalized additive models. In particular the effect the 2012 heat wave that swept across the United States, and which was hypothesized to increase arrivals was examined. Results: While there was no relationship found between the heat index and arrivals on a single day, a non-linear relationship was found between the mean three-day heat index and the number of daily arrivals. As the mean three-day heat index initially increased, the number of arrivals significantly declined. However, as the heat index continued to increase, the number of arrivals increased. It was estimated that there was approximately a 2% increase in arrivals when the mean heat index for three days approached 100°F. This relationship was strongest for adults aged 18-64, as well as for patients arriving with lower acuity. Additionally, a positive relationship was noted between the mean three-day heat index and the length of stay (LOS) for patients in the ED, but no relationship was found for the time from which a patient was first seen to when a disposition decision was made. No significant relationship was found for the effect of the 2012 heat wave on ED arrivals, though it did have an effect on patient LOS. Conclusion: A single hot day has only a limited effect on ED arrivals, but continued hot weather has a cumulative effect. When the heat index is high (~90°F) for a number of days in a row, this curtails peoples activities, but if the heat index is very hot (~100°F) this likely results in an exacerbation of underlying conditions as well as heat-related events that drives an increase in ED arrivals. Periods of high heat also affects the length of stay of patients either by complicating care or by making it more difficult to discharge patients. PMID:26579329

  16. San Andreas Fault Branching at SAFOD From Fault Guided Wave Mapping and P-wave Tomography

    NASA Astrophysics Data System (ADS)

    Malin, P. E.; Shalev, E.

    2005-12-01

    In 2004, drilling in the San Andreas Fault Observatory at Depth Main Hole (MH) stopped at ~2.5 km underground and ~0.7 m short of the SAF surface trace. A seismograph temporarily placed there recorded fault zone guided waves from SAF earthquakes, but only from events more than ~2 km northwest and ~3 km southeast of the seismograph. P-wave tomography of seismograms recorded in the SAFOD Pilot Hole (PH) show the seismograph was near the bottom of a synclinal low velocity zone, which also extends across the surface trace. Evidently, the seismograph was in a branch of the SAF that bounds a sliver of sedimentary rock. Our observations were take with a 3-component, 4.5 Hz seismograph temporarily locked in near the bottom of the MH. The seismograph's position was on the southwestern edge of a structure previously imaged using scattered microearthquake waves as recorded on the PH array. It is also near a highly fractured lithological contact seen in the drill core recovered from the end of the 2004 drilling. Seismograms from SAF microearthquakes originating several km to the northwest and southeast of the seismograph appear to contain large fault zone guided waves ("Fg" waves). These data imply that the structure seen in the migration image and drill core is a significant fault zone with a low velocity core that can trap seismic waves. They further suggest that the fault at the end of the 2004 drilling maybe connected to the active trace of the SAF to the north and south of the SAFOD site. Since the SAFOD site is situated on the flower structure of the Middle Mountain segment of the SAF, this branch may still connect to the surface trace fault but at a depth greater than the target events. Previous geological mapping show that the SAFOD site sits above the Middle Mountain syncline. Our P-wave velocity tomography also suggests that its structure extends deeper than indicated by the surface geology. Further, both the 2004 branch and surface-trace-fault cut through this structure, possibly trapping a sliver of sediments that related to the Great Valley side of the SAF zone. The presence of the branch fault has implications not only for the geology of the SAFOD site but for the mechanics of this fault zone and the drilling of multilateral cores in the MH in 2007.

  17. STS-93 Mission Specialist Coleman arrives at SLF for launch

    NASA Technical Reports Server (NTRS)

    1999-01-01

    STS-93 Mission Specialist Catherine G. 'Cady' Coleman (Ph.D.) shows her sense of humor upon arriving at KSC's Shuttle Landing Facility aboard a T-38 jet aircraft. She and other crew members Commander Eileen Collins, Pilot Jeffrey S. Ashby, and Mission Specialists Steven A. Hawley (Ph.D.) and Michel Tognini of France, with the Centre National d'Etudes Spatiales (CNES), are arriving for pre-launch activities. Coleman is making her second Shuttle flight. The primary mission of STS-93 is the release of the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The new telescope is 20 to 50 times more sensitive than any previous X-ray telescope and is expected to unlock the secrets of supernovae, quasars and black holes.

  18. Experimental study on monitoring CO2 sequestration by conjoint analysis of the P-wave velocity and amplitude.

    PubMed

    Chen, Hao; Yang, Shenglai; Huan, Kangning; Li, Fangfang; Huang, Wei; Zheng, Aiai; Zhang, Xing

    2013-09-01

    CO2 sequestration has been considered to be one of the most straightforward carbon management strategies for industrial CO2 emission. Monitoring of the CO2 injection process is one of the best ways to make sure the safety storage but is also a major challenge in CO2 geological sequestration. Previous field and laboratory researches have shown that seismic methods are among the most promising monitoring methods because of the obvious reduction in P-wave velocities caused by CO2 injection. However, as CO2 injection continues, the P-wave velocity becomes increasingly insensitive according to the pilot projects when CO2 saturation is higher than 20-40%. Therefore, the conventional seismic method needs improvement or replacement to solve its limitations. In this study, P-wave velocity and amplitude responses to supercritical CO2 injection in brine-saturated core samples from Jilin oilfield were tested using core displacement and an ultrasonic detection integrated system. Results showed that neither the P-wave velocity nor amplitude could simply be used to monitor the CO2 injection process because of the insensitive or nonmonotonous response. Consequently, a new index was established by synthetically considering these two parameters to invert and monitor the CO2 process, which can be thought of as a newer and more effective assessment criterion for the seismic method. PMID:23915233

  19. Static and Dynamic Reservoir Characterization Using High Resolution P-Wave Velocity Data in Delhi Field, la

    NASA Astrophysics Data System (ADS)

    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.

  20. [Getting qi and arrival of qi].

    PubMed

    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 diagnosis shall not be neglected in clinical treatment of acupuncture. PMID:25335272

  1. BCS and BEC p-wave pairing in Bose-Fermi gases

    E-print Network

    F. Matera; A. Dellafiore

    2011-09-13

    The pairing of fermionic atoms in a mixture of atomic fermion and boson gases at zero temperature is investigated. The attractive interaction between fermions, that can be induced by density fluctuations of the bosonic background, can give rise to a superfluid phase in the Fermi component of the mixture. The atoms of both species are assumed to be in only one internal state, so that the pairing of fermions is effective only in odd-l channels. No assumption about the value of the ratio between the Fermi velocity and the sound velocity in the Bose gas is made in the derivation of the energy gap equation. The gap equation is solved without any particular "ansatz" for the pairing field or the effective interaction. The p-wave superfluidity is studied in detail. By increasing the strength and/or decreasing the range of the effective interaction a transition of the fermion pairing regime, from the Bardeen-Cooper-Schrieffer state to a system of tightly bound couples can be realized. These composite bosons behave as a weakly-interacting Bose-Einstein condensate.

  2. P-wave velocity in granulites from South India: implications for the continental crust

    NASA Astrophysics Data System (ADS)

    Ramachandran, C.

    1992-01-01

    P-wave velocities ( Vp) were measured in 160 high-grade metamorphic rocks from the South Indian granulite terrain (SGT). The wide variations observed in the Vp of charnockites and gneisses could be due to the complex prograde and retrograde metamorphic histories of the two major rock types of the SGT. The velocity-density relation showed distinct trends for charnockites and gneisses. Initial stages of retrograde metamorphism in charnockites significantly affected their magnetic properties, however, its effect on velocity and density is not diagnostic. Contrasting physical properties on either side of the Palghat-Cauvery (P-C) shear zone lends support for the contention that the P-C shear zone is a major paleosuture. The laboratory mean Vpof the rocks from the northern SGT are comparable with the mid-crustal DSS velocity in the adjacent granite greenstone terrain (GGT), suggesting that the GGT is possibly underlain by a felsic granulite basement. The physical properties of the high-grade metamorphic rocks from SGT are significantly lower than that of the lower crust. The physical properties and tectonic considerations show that the granulites of South India may not be of lower crustal origin and hence not representative of the lower crust, as generally thought. A simplified two-layer crustal model with a predominantly felsic granulite upper crust and a mafic granulite lower crust, is suggested for the SGT.

  3. Annihilation Rate of Heavy 0^{++} P-wave Quarkonium in Relativistic Salpeter Method

    E-print Network

    Guo-Li Wang

    2007-08-26

    Two-photon and two-gluon annihilation rates of P-wave scalar charmonium and bottomonium up to third radial excited states are estimated in the relativistic Salpeter method. We solved the full Salpeter equation with a well defined relativistic wave function and calculated the transition amplitude using the Mandelstam formalism. Our model dependent estimates for the decay widths: $\\Gamma(\\chi_{c0} \\to 2\\gamma)=3.78$ keV, $\\Gamma(\\chi'_{c0} \\to 2\\gamma)=3.51$ keV, $\\Gamma(\\chi_{b0} \\to 2\\gamma)=48.8$ eV and $\\Gamma(\\chi'_{b0} \\to 2\\gamma)=50.3$ eV. We also give estimates of total widths by the two-gluon decay rates: $\\Gamma_{tot}(\\chi_{c0})=10.3$ MeV, $\\Gamma_{tot}(\\chi'_{c0})=9.61$ MeV, $\\Gamma_{tot}(\\chi_{b0})=0.887$ MeV and $\\Gamma_{tot}(\\chi'_{b0})=0.914$ MeV.

  4. Crustal Structure across the Appalachian Orogen in Pennsylvania from P-wave receiver functions

    NASA Astrophysics Data System (ADS)

    Arroyo, G.; Nyblade, A.; Homman, K.

    2014-12-01

    Crustal structure across the Appalachian Orogen from eastern Ohio to New Jersey is investigated using P-wave receiver functions to estimate Moho depths and crustal Vp/Vs ratios. Data for this study comes from the PASEIS and the USArray Transportable Array. The PASEIS seismic network includes 22 broadband seismic stations throughout Pennsylvania that were in installed in February 2013. Preliminary results from H-K stacking show that Moho depth varies greatly across the Appalachians, ranging from 53 km in northern Pennsylvania to only 32 km just west of the New Jersey border. The thickest crust can be found nearest to Lake Erie, and a relatively thick crust is maintained in northeastern Pennsylvania and along the Pennsylvania-Ohio border. Crustal thickness decreases to the southeast, and a rather sharp decrease can be seen well before the start of the Allegheny Front. Crustal thickness remains relatively uniform between 43 and 45km in the Appalachian Mountains, and decreases to 33-38km in the Piedmont province. Vp/Vs values range from 1.75 to 1.83, with no observable pattern to the variation.

  5. Hybrid Theory of P-Wave Electron-Hydrogen Elastic Scattering

    NASA Technical Reports Server (NTRS)

    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.

  6. Effect of p-wave resonances on the threshold behavior of ultracold chemical reactions

    NASA Astrophysics Data System (ADS)

    Côté, R.; Simbotin, I.; Wang, J.; Ghosal, S.

    2013-05-01

    In previous work we have studied the effects of s-wave resonances on the threshold behavior for ultracold chemical reactions, and we now extend our analysis to higher partial waves. Although s-wave is dominant in the limit k --> 0 , p-wave or d-wave contributions can be resonantly enhanced at ultralow energy. If the corresponding partial wave has a resonance pole very close to the threshold, the ultracold regime is divided in two separate domains. The Wigner regime will be displaced towards much lower energies, while the remaining part of the ultracold regime is characterized by an anomalous k-dependence for the inelastic and reaction cross sections; the newly found behavior, ?l (k) ~k 2 l - 5 . For kpole << k <

  7. Hybrid theory of P-wave electron-hydrogen elastic scattering

    NASA Astrophysics Data System (ADS)

    Bhatia, A. K.

    2012-05-01

    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, except at the very lowest energies, they are close to the phase shifts calculated earlier by Bhatia [A. K. Bhatia, Phys. Rev. A10.1103/PhysRevA.69.032714 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 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. Accurate values for the effective range parameters are also calculated.

  8. Analyzing trip cost allowing late arrival under car-following model

    NASA Astrophysics Data System (ADS)

    Tang, Tie-Qiao; Yu, Qiang; Yang, Shi-Chun; Ding, Chuan

    2015-09-01

    In this paper, we use car-following model to explore each commuter’s trip cost and the system’s total trip cost in the commuter’s system allowing late arrival. The numerical results show that each commuter’s trip cost and the system’s total trip cost are related to each commuter’s time headway at the origin and the proportion of the commuters’ late arrival, but the system’s total trip cost has the minimum value that is irrelevant to the proportion of the commuters’ late arrival.

  9. Wake Turbulence Mitigation for Arrivals (WTMA)

    NASA Technical Reports Server (NTRS)

    Williams, Daniel M.; Lohr, Gary W.; Trujillo, Anna C.

    2008-01-01

    The preliminary Wake Turbulence Mitigation for Arrivals (WTMA) concept of operations is described in this paper. The WTMA concept provides further detail to work initiated by the Wake Vortex Avoidance System Concept Evaluation Team and is an evolution of the Wake Turbulence Mitigation for Departure concept. Anticipated benefits about reducing wake turbulence separation standards in crosswind conditions, and candidate WTMA system considerations are discussed.

  10. Practical Living Guide Before Arriving in Israel

    E-print Network

    Jackson, Daniel

    MIT-Israel Practical Living Guide Index Before Arriving in Israel Taking a course on Israel 2 Purchasing airline tickets 2 Visa 3 Housing 3 Stipend 4 Language 4 Practicalities While in Israel Money in Israel 4 Cell phones and other phones 5 Getting around 6 Budget 6 Health insurance and doctors 7 Security

  11. Energy Harvesting Communications with Continuous Energy Arrivals

    E-print Network

    Yener, Aylin

    Energy Harvesting Communications with Continuous Energy Arrivals Burak Varan Kaya Tutuncuoglu Aylin--This work considers an energy harvesting transmit- ter that gathers a continuous flow of energy from intermittent sources, thus relaxing the modeling assumption of discrete amounts of harvested energy present

  12. New Accessions Arriving at Field Records

    USGS Multimedia Gallery

    Materials arrive from across the country to be accessioned and processed at the Denver Library, Field Records Collection. Geologic Discipline scientists are encouraged to deposit their project materials and with the Field Records Collection. Materials in the collection are managed as Federal records...

  13. DNA computing: the arrival of biological mathematics

    E-print Network

    Kari, Lila

    DNA computing: the arrival of biological mathematics Lila Kari1 "Come forth into the light solely by manipulating DNA strings. This marks the first instance of the connection being reversed, instead of categorizing the research in DNA computing as belonging to mathematical biology, we should

  14. DNA computing: the arrival of biological mathematics

    E-print Network

    Kari, Lila

    DNA computing: the arrival of biological mathematics Lila Kari1 "Come forth into the light by manipulating DNA strings. This marks the first instance of the connection being reversed: a mathematical of categorizing the research in DNA computing as belonging to mathematical biology, we should be employing

  15. Automated Measurement of P- and S-Wave Differential Times for Imaging Spatial Distributions of Vp/Vs Ratio, with Moving-Window Cross-Correlation Technique

    NASA Astrophysics Data System (ADS)

    Taira, T.; Kato, A.

    2013-12-01

    A high-resolution Vp/Vs ratio estimate is one of the key parameters to understand spatial variations of composition and physical state within the Earth. Lin and Shearer (2007, BSSA) recently developed a methodology to obtain local Vp/Vs ratios in individual similar earthquake clusters, based on P- and S-wave differential times. A waveform cross-correlation approach is typically employed to measure those differential times for pairs of seismograms from similar earthquakes clusters, at narrow time windows around the direct P and S waves. This approach effectively collects P- and S-wave differential times and however requires the robust P- and S-wave time windows that are extracted based on either manually or automatically picked P- and S-phases. We present another technique to estimate P- and S-wave differential times by exploiting temporal properties of delayed time as a function of elapsed time on the seismograms with a moving-window cross-correlation analysis (e.g., Snieder, 2002, Phys. Rev. E; Niu et al. 2003, Nature). Our approach is based on the principle that the delayed time for the direct S wave differs from that for the direct P wave. Two seismograms aligned by the direct P waves from a pair of similar earthquakes yield that delayed times become zero around the direct P wave. In contrast, delayed times obtained from time windows including the direct S wave have non-zero value. Our approach, in principle, is capable of measuring both P- and S-wave differential times from single-component seismograms. In an ideal case, the temporal evolution of delayed time becomes a step function with its discontinuity at the onset of the direct S wave. The offset in the resulting step function would be the S-wave differential time, relative to the P-wave differential time as the two waveforms are aligned by the direct P wave. We apply our moving-window cross-correlation technique to the two different data sets collected at: 1) the Wakayama district, Japan and 2) the Geysers geothermal field, California. The both target areas are characterized by earthquake swarms that provide a number of similar events clusters. We use the following automated procedure to systematically analyze the two data sets: 1) the identification of the direct P arrivals by using an Akaike Information Criterion based phase picking algorithm introduced by Zhang and Thurber (2003, BSSA), 2) the waveform alignment by the P-wave with a waveform cross-correlation to obtain P-wave differential time, 3) the moving-time window analysis to estimate the S-differential time. Kato et al. (2010, GRL) have estimated the Vp/Vs ratios for a few similar earthquake clusters from the Wakayama data set, by a conventional approach to obtain differential times. We find that the resulting Vp/Vs ratios from our approach for the same earthquake clusters are comparable with those obtained from Kato et al. (2010, GRL). We show that the moving-window cross-correlation technique effectively measures both P- and S-wave differential times for the seismograms in which the clear P and S phases are not observed. We will show spatial distributions in Vp/Vs ratios in our two target areas.

  16. Measurement of parity-nonconserving rotation of neutron spin in the 0.734-eV p-wave resonance of $^{139}La$

    E-print Network

    T. Haseyama; K. Asahi; J. D. Bowman; P. P. J. Delheij; H. Funahashi; S. Ishimoto; G. Jones; A. Masaike; Y. Masuda; Y. Matsuda; K. Morimoto; S. Muto; S. I. Penttilä; V. R. Pomeroy; K. Sakai; E. I. Sharapov; D. A. Smith; V. W. Yuan

    2001-11-21

    The parity nonconserving spin rotation of neutrons in the 0.734-eV p-wave resonance of $^{139}La$ was measured with the neutron transmission method. Two optically polarized $^3He$ cells were used before and behind a a 5-cm long $^{139}La$ target as a polarizer and an analyzer of neutron spin. The rotation angle was carefully measured by flipping the direction of $^3He$ polarization in the polarizer in sequence. The peak-to-peak value of the spin rotation was found to be $ (7.4 \\pm 1.1) \\times 10^{-3} $ rad/cm which was consistent with the previous experiments. But the result was statisticallly improved. The s-p mixing model gives the weak matrix element as $xW = (1.71 \\pm 0.25)$ meV. The value agrees well with the one deduced from the parity-nonconserving longitudinal asymmetry in the same resonance.

  17. NASA's ATM Technology Demonstration-1: Integrated Concept of Arrival Operations

    NASA Technical Reports Server (NTRS)

    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.

  18. Does the arrival index predict physiological stress reactivity in children.

    PubMed

    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. PMID:24930802

  19. Natural selection for earlier male arrival to breeding grounds through direct and indirect effects in a migratory songbird.

    PubMed

    Velmala, William; Helle, Samuli; Ahola, Markus P; Klaassen, Marcel; Lehikoinen, Esa; Rainio, Kalle; Sirkiä, Päivi M; Laaksonen, Toni

    2015-03-01

    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 measured the directional selection differential on male arrival time in the pied flycatcher (Ficedula hypoleuca) using data from 6 years and annual number of fledglings as the fitness proxy. Using structural equation modeling, we were able to take into account the temporal structure of the breeding cycle and the hierarchy between the examined traits. We found directional selection differentials for earlier male arrival date and earlier female laying date, as well as strong selection differential for larger clutch size. These selection differentials were due to direct selection only as indirect selection for these traits was nonsignificant. When decomposing the direct selection for earlier male arrival into direct and indirect effects, we discovered that it was almost exclusively due to the direct effect of male arrival date on fitness and not due to its indirect effects via female traits. In other words, we showed for the first time that there is a direct effect of male arrival date on fitness while accounting for those effects that are mediated by effects of the social partner. Our study thus indicates that natural selection directly favored earlier male arrival in this flycatcher population. PMID:25859326

  20. Natural selection for earlier male arrival to breeding grounds through direct and indirect effects in a migratory songbird

    PubMed Central

    Velmala, William; Helle, Samuli; Ahola, Markus P; Klaassen, Marcel; Lehikoinen, Esa; Rainio, Kalle; Sirkiä, Päivi 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 measured the directional selection differential on male arrival time in the pied flycatcher (Ficedula hypoleuca) using data from 6 years and annual number of fledglings as the fitness proxy. Using structural equation modeling, we were able to take into account the temporal structure of the breeding cycle and the hierarchy between the examined traits. We found directional selection differentials for earlier male arrival date and earlier female laying date, as well as strong selection differential for larger clutch size. These selection differentials were due to direct selection only as indirect selection for these traits was nonsignificant. When decomposing the direct selection for earlier male arrival into direct and indirect effects, we discovered that it was almost exclusively due to the direct effect of male arrival date on fitness and not due to its indirect effects via female traits. In other words, we showed for the first time that there is a direct effect of male arrival date on fitness while accounting for those effects that are mediated by effects of the social partner. Our study thus indicates that natural selection directly favored earlier male arrival in this flycatcher population. PMID:25859326

  1. Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media

    NASA Astrophysics Data System (ADS)

    Pestana, Reynam C.; Ursin, Bjørn; Stoffa, Paul L.

    2012-06-01

    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 |? - ?| 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.

  2. Modeling warning times for the Israel's earthquake early warning system

    NASA Astrophysics Data System (ADS)

    Pinsky, Vladimir

    2015-01-01

    In June 2012, the Israeli government approved the offer of the creation of an earthquake early warning system (EEWS) that would provide timely alarms for schools and colleges in Israel. A network configuration was chosen, consisting of a staggered line of ˜100 stations along the main regional faults: the Dead Sea fault and the Carmel fault, and an additional ˜40 stations spread more or less evenly over the country. A hybrid approach to the EEWS alarm was suggested, where a P-wave-based system will be combined with the S-threshold method. The former utilizes first arrivals to several stations closest to the event for prompt location and determination of the earthquake's magnitude from the first 3 s of the waveform data. The latter issues alarms, when the acceleration of the surface movement exceeds a threshold for at least two neighboring stations. The threshold will be chosen to be a peak acceleration level corresponding to a magnitude 5 earthquake at a short distance range (5-10 km). The warning times or lead times, i.e., times between the alarm signal arrival and arrival of the damaging S-waves, are considered for the P, S, and hybrid EEWS methods. For each of the approaches, the P- and the S-wave travel times and the alarm times were calculated using a standard 1D velocity model and some assumptions regarding the EEWS data latencies. Then, a definition of alarm effectiveness was introduced as a measure of the trade-off between the warning time and the shaking intensity. A number of strong earthquake scenarios, together with anticipated shaking intensities at important targets, namely cities with high populations, are considered. The scenarios demonstrated in probabilistic terms how the alarm effectiveness varies depending on the target distance from the epicenter and event magnitude.

  3. Modeling warning times for the Israel's earthquake early warning system

    NASA Astrophysics Data System (ADS)

    Pinsky, Vladimir

    2014-09-01

    In June 2012, the Israeli government approved the offer of the creation of an earthquake early warning system (EEWS) that would provide timely alarms for schools and colleges in Israel. A network configuration was chosen, consisting of a staggered line of ˜100 stations along the main regional faults: the Dead Sea fault and the Carmel fault, and an additional ˜40 stations spread more or less evenly over the country. A hybrid approach to the EEWS alarm was suggested, where a P-wave-based system will be combined with the S-threshold method. The former utilizes first arrivals to several stations closest to the event for prompt location and determination of the earthquake's magnitude from the first 3 s of the waveform data. The latter issues alarms, when the acceleration of the surface movement exceeds a threshold for at least two neighboring stations. The threshold will be chosen to be a peak acceleration level corresponding to a magnitude 5 earthquake at a short distance range (5-10 km). The warning times or lead times, i.e., times between the alarm signal arrival and arrival of the damaging S-waves, are considered for the P, S, and hybrid EEWS methods. For each of the approaches, the P- and the S-wave travel times and the alarm times were calculated using a standard 1D velocity model and some assumptions regarding the EEWS data latencies. Then, a definition of alarm effectiveness was introduced as a measure of the trade-off between the warning time and the shaking intensity. A number of strong earthquake scenarios, together with anticipated shaking intensities at important targets, namely cities with high populations, are considered. The scenarios demonstrated in probabilistic terms how the alarm effectiveness varies depending on the target distance from the epicenter and event magnitude.

  4. P-wave and s-wave imaging from drill bit seismic data at SAFOD

    NASA Astrophysics Data System (ADS)

    Taylor, S. T.; Miller, D.; Haldorsen, J. B.; Coates, R.; Malin, P.; Shalev, E.

    2005-12-01

    We have used the drill bit seismic technique to develop preliminary images of fracture and shear zones associated with the San Andreas Fault at the SAFOD site, Parkfield, California. Our study included the interpretation of the USGS PSINE surface seismic profile and the drill bit seismic data recorded by three different geophone arrays. Three-component geophones were used in two of the arrays, one of which consisted of a 1.2 km string of geophones in the SAFOD Pilot Hole. The multi-component data allowed us to use both p-wave and s-wave imaging techniques for delineating subsurface structure after updating the velocity models for the site. Our interpretation of the locations and dips of linear features imaged in the migrated drill bit seismic data correlates very well with locations and dips of faults in the PSINE profile. Using the available seismic datasets, we interpret numerous faults to cut the Cenozoic sedimentary cover, the Salinian block, and an apparent wedge of metasediments at the SAFOD site. Based on the structural pattern of downward converging faults and fracture zones, we interpret the fault system to comprise a flower structure that is directly related to the tectonic regime of the San Andreas Fault. The interpretation of a flower structure at SAFOD, which is located 1.8 km SW of the SAF, fits well with the surface geological mapping that has been conducted at the site. This mapping and our data indicates that a pervasive system of fractures and faults trend subparallel to the SAF in a zone up to 3 km SW of the main trace of the fault.

  5. Majorana bands, Berry curvature, and thermal Hall conductivity in the vortex state of a chiral p -wave superconductor

    NASA Astrophysics Data System (ADS)

    Murray, James M.; Vafek, Oskar

    2015-10-01

    Majorana quasiparticles localized in vortex cores of a chiral p -wave superconductor hybridize with one another to form bands in a vortex lattice. We begin by solving a fully microscopic theory describing all quasiparticle bands in a chiral p -wave superconductor in a magnetic field, then use this solution to build localized Wannier wave functions corresponding to Majorana quasiparticles. A low-energy tight-binding theory describing the intervortex hopping of these is then derived, and its topological properties—which depend crucially on the signs of the imaginary intervortex hopping parameters—are studied. We show that the energy gap between the Majorana bands may be either topologically trivial or nontrivial, depending on whether the Chern number contributions from the Majorana bands and those from the background superconducting condensate add constructively or destructively. This topology directly affects the temperature-dependent thermal Hall conductivity, which we also calculate.

  6. Optimal Integration of Departure and Arrivals in Terminal Airspace

    NASA Technical Reports Server (NTRS)

    Xue, Min; Zelinski, Shannon Jean

    2012-01-01

    Coordination of operations with spatially and temporally shared resources such as route segments, fixes, and runways improves the efficiency of terminal airspace management. Problems in this category include scheduling and routing, thus they are normally difficult to solve compared with pure scheduling problems. In order to reduce the computational time, a fast time algorithm formulation using a non-dominated sorting genetic algorithm (NSGA) was introduced in this work and applied to a test case based on existing literature. The experiment showed that new method can solve the whole problem in fast time instead of solving sub-problems sequentially with a window technique. The results showed a 60% or 406 second delay reduction was achieved by sharing departure fixes (more details on the comparison with MILP results will be presented in the final paper). Furthermore, the NSGA algorithm was applied to a problem in LAX terminal airspace, where interactions between 28% of LAX arrivals and 10% of LAX departures are resolved by spatial segregation, which may introduce unnecessary delays. In this work, spatial segregation, temporal segregation, and hybrid segregation were formulated using the new algorithm. Results showed that spatial and temporal segregation approaches achieved similar delay. Hybrid segregation introduced much less delay than the other two approaches. For a total of 9 interacting departures and arrivals, delay reduction varied from 4 minutes to 6.4 minutes corresponding flight time uncertainty from 0 to 60 seconds. Considering the amount of flights that could be affected, total annual savings with hybrid segregation would be significant.

  7. STS-76 crew after arrival at SLF

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-76 Mission Commander Kevin P. Chilton (left); Mission Specialists Linda M. Godwin and Shannon W. Lucid; Pilot Richard A. Searfoss and Mission Specialist Michael 'Rich' Clifford chat shortly after their arrival at KSC's Shuttle Landing Facility. Not shown is Payload Commander Ronald M. Sega. The astronauts' late-night arrival allows them to maintain the shift in their waking and sleeping hours, altered in preparation for their upcoming spaceflight. The Space Shuttle Atlantis is scheduled to lift off on STS-76 around 3:35 a.m. EST, March 21, with one of the primary mission objectives being the third docking between the U.S. Shuttle and the Russian Space Station Mir.

  8. Geographic Variation in Tsunami Warning Center Response Time: Identifying Areas of Greatest Concern

    NASA Astrophysics Data System (ADS)

    Becker, N. C.; Sardiña, V.; Cessaro, R. K.; Fryer, G. J.; Weinstein, S.

    2010-12-01

    Close to a tsunami source, people who feel an earthquake can self-evacuate to higher ground if they understand the significance of severe ground shaking. Far from a tsunami source, or even in the case of nearby “slow” earthquakes, people can only evacuate coastal areas if they receive a timely warning from a local civil defense agency or a dedicated tsunami warning center (TWC). This reality requires a TWC to operate differently from a typical seismic observatory, since a TWC must estimate the earthquake source parameters as fast as possible with a minimum of seismic data, then use these estimated source parameters to assess the tsunami-generating potential of the earthquake and issue warnings when appropriate. Using known constraints for likely tsunamigenic earthquakes such as location, tsunami and P-wave travel time, and the amount of data and time required to analyze an earthquake, we can predict how rapidly a TWC can issue a warning for the coastlines it is charged to protect. In our analysis we use the digitized convergent margins from the UTIG plate boundary data set as a proxy for subduction-zone earthquakes. We then calculate P-wave travel time on the surface of the earth using the IASPEI P-wave travel time table for shallow (33 km) sources. We also use these proxy sources to calculate tsunami travel time from these sources to coastlines with a 64-node Huygens construction method and GEBCO 2-minute global bathymetery. We estimate the warning center's analysis time for these proxy sources by summing the time required for a specific number of seismic stations to register the P-waves, the data transmission latency time from the stations to the warning center, and the typical time required to process these data. We apply this method to the Pacific Tsunami Warning Center (PTWC), which mitigates tsunami hazards in the Pacific Ocean, the Indian Ocean, and the Caribbean Sea. For this purpose PTWC collects and analyzes teleseismic data from a global seismic network. We estimate the time required for P-waves generated by subduction zone earthquakes to reach the number of stations typically needed to produce a tsunami warning. We then project these data to the nearest coastlines to produce a table of P-wave reception times for earthquakes affecting these coastlines. Next, we subtract these reception time values from the travel time of tsunamis from these earthquakes to the coastlines. The resulting data sets and corresponding maps reveal the time window of opportunity for populations to act upon PTWC's warnings and safely evacuate these coastal areas. Our maps show that while most of the world's coastal populations have an hour or more to evacuate after receiving a warning from PTWC, certain coastlines have less than an hour, and in the worst cases, the first tsunami wave will arrive before PTWC can warn the affected areas. While our analysis reveals response problems for a given tsunami warning center, it also highlights the solutions by indicating where to install and monitor additional seismic stations, and where data outages could have the greatest negative impact, thus showing where redundancy in station deployment is most critical.

  9. STS-85 Crew Arrival for TCDT

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Space Shuttle Mission STS-85 crew arrives at the Shuttle Landing Facility for their mission's Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. They are (from left): Mission Specialist Stephen K. Robinson; Payload Commander N. Jan Davis; Mission Specialist Robert L. Curbeam; Commander Curtis L. Brown, Jr.; Pilot Kent V. Rominger; and Payload Specialist Bjarni V. Tryggvason. The liftoff for STS-85 is targeted for August 7, 1997.

  10. STS-76 crew after arrival at SLF

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-76 Mission Commander Kevin P. Chilton (second from left) chats with Mission Specialist Shannon W. Lucid (left); Pilot Richard A. Searfoss and Mission Specialist Michael 'Rich' Clifford shortly after their arrival at KSC's Shuttle Landing Facility. The Space Shuttle Atlantis is scheduled to lift off on STS-76 around 3:35 a.m. EST, March 21, with one of the primary mission objectives being the third docking between the U.S. Shuttle and the Russian Space Station Mir.

  11. Forecasting interplanetary ejecta arrival at 1 AU

    NASA Astrophysics Data System (ADS)

    dal Lago, A.; Vieira, L. E.; Echer, E.; Gonzalez, W. D.; Clua de Gonzalez, A. L.; Guarnieri, F. L.; Santos, J.; Schwenn, R.; Schuch, N. J.

    A big challenge in space weather forecasting is the prediction of arrival of an interplanetary disturbance at earth. Many attempts have been done, and some forecasting models have been proposed. We focus on the subset of solar-interplanetary events which have shown interplanetary ejecta at 1 AU. To identify interplanetary ejecta at 1 AU we use visual inspection of the cases, based on the criterion of intense and smooth magnetic field, observed by the Advanced Composition Explorer (ACE). For forecasting the arrival of the interplanetary ejecta at 1 AU we used the lateral expansion speed of the coronal mass ejection, measured approximately perpendicular to the single plane-of-sky CME speed, as defined by Schwenn et al (2001), using observations from the Large Angle and Spectroscopic Coronagraph (LASCO), aboard the Solar and Heliospheric Observatory (SOHO). The data set is from January 1997 to mid April 2001, and a number of 38 LASCO CMEs were identified to be correlated with interplanetary ejecta at 1 AU. Results indicate that forecasting the arrival at 1 AU of the sub set of interplanetary ejecta is very well done by LASCO CME speed observations, being much better than the predictions for the complete set of interplanetary disturbances, like shocks/sheath structures.

  12. Resummation of in-medium ladder diagrams: s-wave effective range and p-wave interaction

    E-print Network

    N. Kaiser

    2012-10-02

    A recent work on the resummation of fermionic in-medium ladder diagrams to all orders is extended by considering the effective range correction in the s-wave interaction and a (spin-independent) p-wave contact-interaction. A two-component recursion generates the in-medium T-matrix at any order when off-shell terms spoil the factorization of multi-loop diagrams. The resummation to all orders is achieved in the form of a geometrical series for the particle-particle ladders, and through an arctangent-function for the combined particle-particle and hole-hole ladders. One finds that the effective range correction changes the results in the limit of large scattering length considerably, with the effect that the Bertsch parameter $\\xi_n$ nearly doubles. Applications to the equation of state of neutron matter at low density are also discussed. For the p-wave contact-interaction the resummation to all orders is facilitated by decomposing tensorial loop-integrals with a transversal and a longitudinal projector. The enhanced attraction provided by the p-wave ladder series has its origin mainly in the coherent sum of Hartree and Fock contributions.

  13. Dispersion durations of P-wave and QT interval in children with congenital heart disease and pulmonary arterial hypertension.

    PubMed

    Sap, Fatih; Karata?, Zehra; Altin, Hakan; Alp, Hayrullah; Oran, Bülent; Baysal, Tamer; Karaarslan, Sevim

    2013-03-01

    This study aimed to investigate homogeneity disorders of ventricular repolarization and atrial conduction via QT dispersion and P-wave dispersion in children with congenital heart disease (CHD) and pulmonary arterial hypertension (PAH). Three groups of 20 each were generated and involved in this study. The first group included 20 children with both CHD and PAH. The second group consisted of 20 children with CHD but no PAH, and the third group was composed of 20 age- and sex-matched healthy children. Electrocardiographic records were used to determine P-wave, QT, and corrected QT (QTc) dispersions. The pulmonary hypertension group compared with the group having no pulmonary hypertension and the control group showed a significantly longer P-wave dispersion duration (39.10 ± 9.54 vs. 26.30 ± 4.99 ms, p < 0.001; and 24.80 ± 6.94 ms, p < 0.001, respectively) and QT dispersion duration (52.80 ± 15.11 vs. 37.60 ± 6.00 ms, p < 0.001; and 35.00 ± 7.77 ms, p < 0.001, respectively). In addition, the durations of maximum QTc and QTc dispersion were significantly longer in pulmonary hypertension group than in the other two groups. The risk of atrial and ventricular arrhythmia was found to be increased in the patients with both CHD and PAH. Physicians should pay close attention to possible atrial and ventricular arrhythmias during the treatment and follow-up evaluation of these patients. PMID:22972516

  14. GMTI Direction of Arrival Measurements from Multiple Phase Centers.

    SciTech Connect

    Doerry, Armin W.; Bickel, Douglas L.

    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.

  15. Solar energetic particle arrival at Mars due to the 27 January 2012 solar storm

    NASA Astrophysics Data System (ADS)

    Frahm, R. A.; Sharber, J. R.; Winningham, J. D.; Elliott, H. A.; Howard, T. A.; DeForest, C. E.; Odstr?il, D.; Kallio, E.; McKenna-Lawlor, S.; Barabash, S.

    2013-06-01

    On January 27, 2012, an X-class flare brightened on the Sun at 18:15 UT. This event was associated with the generation of a high-energy stream of Solar Energetic Particles (SEPs) advancing along the Interplanetary Magnetic Field (IMF) which arrived at Mars in about 39 minutes. A Coronal Mass Ejection (CME) arrived at Mars several days later. The Electron Spectrometer (ELS), a part of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) experiment on the European Mars Express (MEx) Spacecraft, associatively detected elevated background levels of penetrating particle radiation which abruptly increased above the baseline level by two orders of magnitude within several hours after first arrival, allowing the particle arrival time to be accurately determined from this gradual SEP. As Mars reacted to the SEP, the atmosphere heated driving expansion of the ionosphere.

  16. Automated Conflict Resolution, Arrival Management and Weather Avoidance for ATM

    NASA Technical Reports Server (NTRS)

    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.

  17. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume VI S-Wave Measurements in Borehole C4997 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

    SciTech Connect

    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.

  18. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume V S-Wave Measurements in Borehole C4996 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

    SciTech Connect

    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.

  19. 7 CFR 352.7 - Notice of arrival.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... § 352.7 Notice of arrival. Immediately upon arrival of any shipment of plants or plant products (including noxious weeds) subject to this part and covered by a specific permit, the importer shall submit in duplicate through the...

  20. 19 CFR 122.154 - Notice of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... AIR COMMERCE REGULATIONS Flights to and From Cuba § 122.154 Notice of arrival. (a) Application. All aircraft entering the U.S. from Cuba must give advance notice of arrival, unless it is an Office of...

  1. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93...arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a port...The region from which the elephant, hippopotamus, rhinoceros, or tapir was...

  2. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93...arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a port...The region from which the elephant, hippopotamus, rhinoceros, or tapir was...

  3. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93...arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a port...The region from which the elephant, hippopotamus, rhinoceros, or tapir was...

  4. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93...arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a port...The region from which the elephant, hippopotamus, rhinoceros, or tapir was...

  5. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93...arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a port...The region from which the elephant, hippopotamus, rhinoceros, or tapir was...

  6. 19 CFR 122.118 - Exportation from port of arrival.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Exportation from port of arrival. 122.118 Section... Exportation from port of arrival. (a) Application. Transit air cargo may be transferred for exportation from any port of arrival under this section. The port director may require any supervision necessary...

  7. 19 CFR 122.118 - Exportation from port of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Exportation from port of arrival. 122.118 Section... Exportation from port of arrival. (a) Application. Transit air cargo may be transferred for exportation from any port of arrival under this section. The port director may require any supervision necessary...

  8. Bridging over p-wave pi-production and weak processes in few-nucleon systems with chiral perturbation theory

    E-print Network

    Satoshi X. Nakamura

    2008-05-13

    I study an aspect of chiral perturbation theory (\\chi PT) which enables one to ``bridge'' different reactions. That is, an operator fixed in one of the reactions can then be used to predict the other. For this purpose, I calculate the partial wave amplitude for the p-wave pion production (pp\\to pn\\pi^+) using the pion production operator from the lowest and the next nonvanishing orders. The operator includes a contact operator whose coupling has been fixed using a matrix element of a low-energy weak process (pp\\to de^+\

  9. Fast computation of arrival times in heterogeneous media Inga Berrea

    E-print Network

    Karlsen, Kenneth Hvistendahl

    that was initiated in (K.H. Karlsen, K.-A. Lie, and N.H. Risebro. A fast marching method for reservoir simulation with a porous medium. In reservoir simulation, these fluids are typically oil and water. Computational for different flow resistance of the two fluids. A complete model must also include an equation for the fluid

  10. Automatic recognition of T and teleseismic P waves by statistical analysis of their spectra: An application to continuous records of moored hydrophones

    NASA Astrophysics Data System (ADS)

    Sukhovich, Alexey; Irisson, Jean-Olivier; Perrot, Julie; Nolet, Guust

    2014-08-01

    A network of moored hydrophones is an effective way of monitoring seismicity of oceanic ridges since it allows detection and localization of underwater events by recording generated T waves. The high cost of ship time necessitates long periods (normally a year) of autonomous functioning of the hydrophones, which results in very large data sets. The preliminary but indispensable part of the data analysis consists of identifying all T wave signals. This process is extremely time consuming if it is done by a human operator who visually examines the entire database. We propose a new method for automatic signal discrimination based on the Gradient Boosted Decision Trees technique that uses the distribution of signal spectral power among different frequency bands as the discriminating characteristic. We have applied this method to automatically identify the types of acoustic signals in data collected by two moored hydrophones in the North Atlantic. We show that the method is capable of efficiently resolving the signals of seismic origin with a small percentage of wrong identifications and missed events: 1.2% and 0.5% for T waves and 14.5% and 2.8% for teleseismic P waves, respectively. In addition, good identification rates for signals of other types (iceberg and ship generated) are obtained. Our results indicate that the method can be successfully applied to automate the analysis of other (not necessarily acoustic) databases provided that enough information is available to describe statistical properties of the signals to be identified.

  11. Real-time processing of earthquake information in Iceland.

    NASA Astrophysics Data System (ADS)

    Kjartansson, E.; Vogfjord, K. S.; Hjaltadottir, S.; Sveinbjornsson, H.; Armannsdottir, S.; Gudmundsson, G. B.

    2009-04-01

    Tools for real-time analysis have been implemented at seismic stations in the SIL system in Iceland, as a part of the Icelandic Meteorological Office participation in the SAFER and TRANSFER projects. These tools include processes to support alert maps and Shake Maps, first steps towards fast magnitude determination based on dominant frequency, and the development of procedures to map faults in near-real-time. Data for alert maps and Shake Maps is obtained using a real-time process that monitors both ground velocity and acceleration in 4 separate frequency bands at each station: 4-50 Hz, 1-10 Hz, 0.25-2.5 Hz and 0.05-0.5 Hz. A reference level is maintained for horizontal and vertical components in each frequency band, such that it is exceeded a few times per hour. When signals exceed this level by more than 50%, a report is sent to the processing center. When 5 or more stations send reports within a time interval of 20 seconds, alert maps are generated. The alert maps show observed values for each station, including peak ground velocity and arrival times for peaks in ground motion and first break. An attempt is also made to solve for the location of the event. The location solution is based on the assumption that time when the vertical component first exceeds the reference level by a certain amount indicate the arrival of the P wave from an earthquake. Before searching for a location solution, the arrival times for different stations are compared and stations are dropped so that no time differences are greater than the time that it takes a P wave to travel from one station to another. The location calculation uses a fixed depth ( 4 km ) and uses a parametric travel time curve that is based on observations from South Iceland. All possible combinations of 3 stations are used to compute potential solutions; the location that yields the lowest sum of absolute residuals is then found. Once the location has been determined, conventional magnitude can be calculated, using recently refined magnitude-distance relations for Icelandic earthquakes. When a good fit is obtained for at least 5 stations, for both arrival times and amplitudes, and the magnitude indicated is greater than 2.0, a Shake Map is generated and placed online automatically. The Shake Maps are usually ready within 2 minutes of the earthquake. The maps can be accessed at http://hraun.vedur.is/ja/alert. This real-time analysis has been operational on over 40 stations in the SIL system since early September 2008. These tools have yielded accurate magnitude estimations for nearly all earthquakes that have been felt in Iceland during this period. In order to extend coverage to surrounding ocean areas, we are working on having access to real-time data from a few seismic stations around the North-Atlantic. This should enable early warning for large offshore earthquakes. Mapping of faults in near-real-time fault is performed by using double-difference relocation of automatically located microearthquakes, relative to a library of events already located with high precision. Thus, taking advantage of the tens of thousands of earthquakes in South Iceland that have been relatively located. Automation of the relocation process is under development. When completed, the process will enable near-real-time delineation of activated faults by the distribution of microearthquakes.

  12. The stratospheric arrival pair in infrasound propagation.

    PubMed

    Waxler, Roger; Evers, Läslo G; Assink, Jelle; Blom, Phillip

    2015-04-01

    The ideal case of a deep and well-formed stratospheric duct for long range infrasound propagation in the absence of tropospheric ducting is considered. A canonical form, that of a pair of arrivals, for ground returns of impulsive signals in a stratospheric duct is determined. The canonical form is derived from the geometrical acoustics approximation, and is validated and extended through full wave modeling. The full caustic structure of the field of ray paths is found and used to determine phase relations between the contributions to the wavetrain from different propagation paths. Finally, comparison with data collected from the 2005 fuel gas depot explosion in Buncefield, England is made. The correspondence between the theoretical results and the observations is shown to be quite good. PMID:25920837

  13. P-1 truss arrival at KSC

    NASA Technical Reports Server (NTRS)

    2000-01-01

    On July 26, 2000 the P-1 truss arrived at Kennedy Space Center's Shuttle Landing Facility aboard its 'Super Guppy' transport. The transport's cargo bay was opened showing the American flag and NASA logo as the P-1 truss was off loaded in preparation for movement to the Operations and Checkout Building for processing. The P-1 truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, SO, during the spring assembly flight. The 33,000- pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the International Space Station's radiators away form the sun to increase their maximum cooling efficiency.

  14. P-1 truss arrival at KSC

    NASA Technical Reports Server (NTRS)

    2000-01-01

    On July 26, 2000 the P-1 truss arrived at Kennedy Space Center's Shuttle Landing Facility aboard its 'Super Guppy' transport. The transport's cargo bay was opened showing the American flag and NASA logo as the P-1 truss was off loaded in preparation for movement to the Operations and Checkout Building for processing. The P-1 truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, SO, during the spring assembly flight. The 33,000- pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the International Space Station's radiators away from the sun to increase their maximum cooling efficiency.

  15. Pore-Scale Modeling of Pore Structure Effects on P-Wave Scattering Attenuation in Dry Rocks

    PubMed Central

    Li, Tianyang; Qiu, Hao; Wang, Feifei

    2015-01-01

    Underground rocks usually have complex pore system with a variety of pore types and a wide range of pore size. The effects of pore structure on elastic wave attenuation cannot be neglected. We investigated the pore structure effects on P-wave scattering attenuation in dry rocks by pore-scale modeling based on the wave theory and the similarity principle. Our modeling results indicate that pore size, pore shape (such as aspect ratio), and pore density are important factors influencing P-wave scattering attenuation in porous rocks, and can explain the variation of scattering attenuation at the same porosity. From the perspective of scattering attenuation, porous rocks can safely suit to the long wavelength assumption when the ratio of wavelength to pore size is larger than 15. Under the long wavelength condition, the scattering attenuation coefficient increases as a power function as the pore density increases, and it increases exponentially with the increase in aspect ratio. For a certain porosity, rocks with smaller aspect ratio and/or larger pore size have stronger scattering attenuation. When the pore aspect ratio is larger than 0.5, the variation of scattering attenuation at the same porosity is dominantly caused by pore size and almost independent of the pore aspect ratio. These results lay a foundation for pore structure inversion from elastic wave responses in porous rocks. PMID:25961729

  16. Two-Photon and Two-gluon Decays of $0^{++}$ and $2^{++}$ P-wave Heavy Quarkonium States

    E-print Network

    Pham, T N

    2010-01-01

    By neglecting the relative quark momenta in the propagator term, the two-photon and two-gluon decay amplitude of heavy quarkonia states can be written as a local heavy quark field operator matrix element which could be obtained from other processes or computed with QCD sum rules technique or lattice simulation, as shown in a recent work on $\\eta_{c,b}$ two-photon decays. In this talk, I would like to discuss a similar calculation on $P$-wave $\\chi_{c0,2}$ and $\\chi_{b0,2}$ two-photon decays. We show that the effective Lagrangian for the two-photon decays of the $P$-wave $\\chi_{c0,2}$ and $\\chi_{b0,2}$ is given by the heavy quark energy-momentum tensor local operator and its trace, the $\\bar{Q}Q$ scalar density. A simple expression for $\\chi_{c0}$ two-photon and two-gluon decay rate in terms of the $f_{\\chi_{c0}}$ decay constant, similar to that of $\\eta_{c}$ is obtained. From the existing QCD sum rules value for $f_{\\chi_{c0}}$, we get $5\\rm\\,keV$ for the $\\chi_{c0}$ two-photon width, somewhat larger than mea...

  17. Broad band estimates of the seismic source functions of Nevada explosions from far-field observations of P waves

    NASA Astrophysics Data System (ADS)

    Douglas, Alan

    One widely used method of obtaining information on the seismic source functions of underground explosions is to compute seismograms using models of the earth, source and seismograph and try and match these to the observed. This process is essentially one of testing the compatibility of the models with observations. An alternative method of obtaining source information is to analyse broad band P seismograms corrected for anelastic attenuation. The main pulses contributing to the signal can be observed on such seismograms and the parameters of the pulses measured. In this paper examples are shown of broad band P seismograms for Nevada explosions. The data are from 39 Nevada explosions (38 fired at the Nevada Test Site proper and one, FAULTLESS, fired at Hot Creek Valley to the north of the test site) recorded at Eskdalemuir, Scotland, supplemented for a few of the explosions with seismograms recorded at stations of the Long Range Seismic Measurements network. To correct for anelastic attenuation requires an estimate of the variation of t* with frequency, t* being the ratio of travel time to specific quality factor. Two models are investigated: for one, t* = 0.35 s and is independent of frequency; for the other t* is frequency-dependent. The frequency-dependent model, however, is rejected as it appears to result in overcorrection of frequencies around 2 Hz. The deconvolved seismograms derived using the frequency-independent t* show significant variability between explosions. However, most of the explosions at the Pahute Mesa fired at depths greater than 819 m are broadly similar and show a roughly systematic move to longer duration with increasing depth—which presumably correlates with increasing yield (ignoring the explosion SCOTCH which was overburied). The shallowest explosion of this sequence, HALFBEAK, has a yield of 365 kt and the largest yield of the deeper explosions is greater than 1000 kt. From this yield information it would appear that the duration scales roughly as (yield) V which is the scaling law predicted by the Mueller-Murphy (M-M) model. The rise times of the P pulses are, however, larger than those predicted by the M-M model and scale roughly as (yield)1/3 although the scatter in the observations is large. Most of the seismograms show P closely followed by an arrival (App) of negative polarity which might be interpreted as pP. Following ApP there is usually a positive arrival which may be larger than P and which has been attributed to the effects of spalling at the free surface above the source. The ApP-P time for most explosions is significantly longer than predicted from the known depth of firing. The deconvolved seismograms show that the P radiation from explosions is not well described by idealised point compressional source models and that a dynamic model of the explosion source needs to be developed that takes account of the observations from such seismograms.

  18. Recent Depth determination of Moderate Earthquakes in Brazil Using Teleseismic P-wave Modeling and pP and sP phases

    NASA Astrophysics Data System (ADS)

    Dias, F.; Assumpcao, M.

    2013-05-01

    We determined depths of shallow ( depth < 25 km) recent earthquakes with moderate magnitude (range of 3 to 5 mb) in Brazil using teleseismic P-waves modeling of P, pP and sP phases The events are located in the Pantanal Basin, São Francisco Craton and Amazon river fan. The stations (delta > 25 °) were grouped according to distance and azimuth and every record was visually inspected; those with a good signal/noise ratio (SNR) were divided in windows of ten degrees distance and stacked. We usually consider groups with at least two stations, but sometimes, a good record of single station with different azimuth was also used to improve the focal depth. We used the hudson96 program of Herrmann seismology package (Herrmann, 2002) to do the modeling. One advantage of the program is the possibility of using different velocity models for the source, the path and the receiver. We used the dispersion of Rayleigh and Loves waves record in closer stations to build a velocity model of the source, and the ak135 model for the path and the receiver. The modeling is especially useful for the shallowest events (less than ~ 1 km) where the P, pP, sP phases are so close that is not possible to separate them. For three earthquakes in the Amazon Fan: 5.3 mb in 1998, 4.8 mb in 2006 and 5.1 mb in 2007, we identified the depth phase pP by stacking teleseismic records grouped by distance and azimuth. Using refraction seismic models in the region (Watts et al., 2009) we determined a depth of 14 km for the 2007 event and 26 km for 1998 event. In the event of 2006, closer to the coast, it was not possible see the pP phase, indicating that it was a shallow earthquake. Synthetic seismograms were calculated to constrain 2 km depth. For the event in the Pantanal basin (4.8 mb) the pP-P time difference indicates a 5.7 km depth, while teleseismic P-wave modeling gives a 6.0 km depth. This shows that the earthquake occurred in basement beneath the sedimentary basin. The 3.3 Mw event of Brasilia (central region) in 2000 resulted in 3 km depth by waveform-modelling. The depth of the 2007 event in the São Francisco craton was modelled as 1.3 km. It was the main event (4.9 mb) of a sequence started in May 2007, studied by Chimpliganond et al.(2010) who determined a focal depth of 0.7 km using local stations, consistent with our results. By modeling the teleseismic P waves we determined focal depths and compared with some previous determination available. It was shown that this technique is capable of recovering focal depth from shallow events when P, pP, sP are difficult to identify. Also, it is a useful technique to retrieve focal depth when local stations are not available, as in most cases studied in Brazil.

  19. Modelling the arrival of invasive organisms via the international marine shipping network: a Khapra beetle study.

    PubMed

    Paini, Dean R; Yemshanov, Denys

    2012-01-01

    Species can sometimes spread significant distances beyond their natural dispersal ability by anthropogenic means. International shipping routes and the transport of shipping containers, in particular are a commonly recognised pathway for the introduction of invasive species. Species can gain access to a shipping container and remain inside, hidden and undetected for long periods. Currently, government biosecurity agencies charged with intercepting and removing these invasive species when they arrive to a county's border only assess the most immediate point of loading in evaluating a shipping container's risk profile. However, an invasive species could have infested a container previous to this point and travelled undetected before arriving at the border. To assess arrival risk for an invasive species requires analysing the international shipping network in order to identify the most likely source countries and the domestic ports of entry where the species is likely to arrive. We analysed an international shipping network and generated pathway simulations using a first-order Markov chain model to identify possible source ports and countries for the arrival of Khapra beetle (Trogoderma granarium) to Australia. We found Kaohsiung (Taiwan) and Busan (Republic of Korea) to be the most likely sources for Khapra beetle arrival, while the port of Melbourne was the most likely point of entry to Australia. Sensitivity analysis revealed significant stability in the rankings of foreign and Australian ports. This methodology provides a reliable modelling tool to identify and rank possible sources for an invasive species that could arrive at some time in the future. Such model outputs can be used by biosecurity agencies concerned with inspecting incoming shipping containers and wishing to optimise their inspection protocols. PMID:22970258

  20. Modelling the Arrival of Invasive Organisms via the International Marine Shipping Network: A Khapra Beetle Study

    PubMed Central

    Paini, Dean R.; Yemshanov, Denys

    2012-01-01

    Species can sometimes spread significant distances beyond their natural dispersal ability by anthropogenic means. International shipping routes and the transport of shipping containers, in particular are a commonly recognised pathway for the introduction of invasive species. Species can gain access to a shipping container and remain inside, hidden and undetected for long periods. Currently, government biosecurity agencies charged with intercepting and removing these invasive species when they arrive to a county’s border only assess the most immediate point of loading in evaluating a shipping container’s risk profile. However, an invasive species could have infested a container previous to this point and travelled undetected before arriving at the border. To assess arrival risk for an invasive species requires analysing the international shipping network in order to identify the most likely source countries and the domestic ports of entry where the species is likely to arrive. We analysed an international shipping network and generated pathway simulations using a first-order Markov chain model to identify possible source ports and countries for the arrival of Khapra beetle (Trogoderma granarium) to Australia. We found Kaohsiung (Taiwan) and Busan (Republic of Korea) to be the most likely sources for Khapra beetle arrival, while the port of Melbourne was the most likely point of entry to Australia. Sensitivity analysis revealed significant stability in the rankings of foreign and Australian ports. This methodology provides a reliable modelling tool to identify and rank possible sources for an invasive species that could arrive at some time in the future. Such model outputs can be used by biosecurity agencies concerned with inspecting incoming shipping containers and wishing to optimise their inspection protocols. PMID:22970258

  1. Velocity and Attenuation Structure of the Tibetan Lithosphere using Seismic Attributes of P-waves from Regional Earthquakes Recorded by the Hi-CLIMB Array

    NASA Astrophysics Data System (ADS)

    Nowack, R. L.; Bakir, A. C.; Griffin, J.; Chen, W.; Tseng, T.

    2010-12-01

    Using data from regional earthquakes recorded by the Hi-CLIMB array in Tibet, we utilize seismic attributes from crustal and Pn arrivals to constrain the velocity and attenuation structure in the crust and the upper mantle in central and western Tibet. The seismic attributes considered include arrival times, Hilbert envelope amplitudes, and instantaneous as well as spectral frequencies. We have constructed more than 30 high-quality regional seismic profiles, and of these, 10 events have been selected with excellent crustal and Pn arrivals for further analysis. Travel-times recorded by the Hi-CLIMB array are used to estimate the large-scale velocity structure in the region, with four near regional events to the array used to constrain the crustal structure. The travel times from the far regional events indicate that the Moho beneath the southern Lhasa terrane is up to 75 km thick, with Pn velocities greater than 8 km/s. In contrast, the data sampling the Qiangtang terrane north of the Bangong-Nujiang (BNS) suture shows thinner crust with Pn velocities less than 8 km/s. Seismic amplitude and frequency attributes have been extracted from the crustal and Pn wave trains, and these data are compared with numerical results for models with upper-mantle velocity gradients and attenuation, which can strongly affect Pn amplitudes and pulse frequencies. The numerical modeling is performed using the complete spectral element method (SEM), where the results from the SEM method are in good agreement with analytical and reflectivity results for different models with upper-mantle velocity gradients. The results for the attenuation modeling in Tibet imply lower upper mantle Q values in the Qiangtang terrane to the north of the BNS compared to the less attenuative upper mantle beneath the Lhasa terrane to the south of the BNS.

  2. STS-93 crew leaves SLF after arrival for launch

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The STS-93 crew leave the Shuttle Landing Facility after answering questions for the media and posing for photographers, whose shadows stretch across the SLF. From left are Mission Specialists Michel Tognini of France, who is with the Centre National d'Etudes Spatiales (CNES) and Steven A. Hawley (Ph.D.), Commander Eileen M. Collins (waving), Mission Specialist Catherine G. 'Cady' Coleman (Ph.D.), and Pilot Jeffrey S. Ashby. The crew arrived at KSC for pre-launch activities. Collins is the first woman to serve as mission commander. The primary mission of STS-93 is the release of the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The new telescope is 20 to 50 times more sensitive than any previous X-ray telescope and is expected to unlock the secrets of supernovae, quasars and black holes.

  3. Airborne Precision Spacing (APS) Dependent Parallel Arrivals (DPA)

    NASA Technical Reports Server (NTRS)

    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.

  4. Using coprime microphone arrays for direction-of-arrival estimation

    NASA Astrophysics Data System (ADS)

    Nichols, John Paul

    Direction-of-arrival estimation using microphone arrays requires many sensors to reduce beam width in order to achieve precise location estimation in a noisy environment. Coprime linear microphone arrays allow for narrow beams with fewer sensors. Coprime sensing is a type of sparse sensing, meaning that the microphone elements are fewer and more spaced out than in a traditional array without sacrificing resolution, but requiring more post-processing. A coprime microphone array is made up of two overlapping uniform linear arrays with M and N sensors, where M and N are coprime. By applying spatial filtering with both arrays and combining their outputs, M+N sensors can yield MN directional bands. In this work, the coprime array theory is implemented experimentally for the first time with a microphone array to estimate the location of multiple uncorrelated sources in a noisy environment. Both simulated and measured results will be discussed.

  5. the P-wave upper mantle structure beneath an active spreading center: The Gulf of California

    NASA Technical Reports Server (NTRS)

    Walck, M. C.

    1983-01-01

    Detailed analysis of short period travel time, and waveform data reveals the upper mantle structure beneath an oceanic ridge to depths of 900 km. More than 1400 digital seismograms from earthquakes in Mexico and central America recorded at SCARLET yield 1753 travel times and 58 direct measurements of short period travel time as well as high quality, stable waveforms. The 29 events combine to form a continuous record section from 9 deg to 40 deg with an average station spacing of less than 5 km. First the travel times are inverted. Further constraints arise from the observed relative amplitudes of mantle phases, which are modeled by trial and error.

  6. Interactions between a Candidate Gene for Migration (ADCYAP1), Morphology and Sex Predict Spring Arrival in Blackcap Populations

    PubMed Central

    2015-01-01

    Avian research has begun to reveal associations between candidate genes and migratory behaviors of captive birds, yet few studies utilize genotypic, morphometric, and phenological data from wild individuals. Previous studies have identified an association between ADCYAP1 polymorphism and autumn migratory behavior (restlessness, or zugunruhe), but little is known about the relationship between ADCYAP1 and spring migratory behavior. The timing of spring migration and arrival to the breeding ground are phenological traits which could be particularly favorable for establishing territories and acquiring mates, thus important to fitness and reproductive success. Here, we investigated how individual genotypic ADCYAP1 variation and phenotypic variation (wing length and shape) of blackcaps (Sylvia atricapilla) affect spring arrival date across nine natural populations in Europe. We hypothesized that longer alleles should be associated with earlier spring arrival dates and expected the effect on arrival date to be stronger for males as they arrive earlier. However, we found that longer wings were associated with earlier spring arrival to the breeding grounds for females, but not for males. Another female-specific effect indicated an interaction between ADCYAP1 allele size and wing pointedness on the response of spring arrival: greater allele size had a positive effect on spring arrival date for females with rounder wings, while a negative effect was apparent for females with more pointed wings. Also, female heterozygotes with pointed wing tips arrived significantly earlier than both homozygotes with pointed wings and heterozygotes with round wings. Stable isotope ratios (?2H) of a subset of blackcaps captured in Freiburg in 2011 allowed us also to assign individuals to their main overwintering areas in northwest (NW) and southwest (SW) Europe. NW males arrived significantly earlier to the Freiburg breeding site than both SW males and females in 2011. NW females had more pointed wing tips compared to SW females, but no difference in ADCYAP1 allele size was found between the different migration routes. PMID:26684459

  7. Optimal Integration of Departures and Arrivals in Terminal Airspace

    NASA Technical Reports Server (NTRS)

    Xue, Min; Zelinski, Shannon Jean

    2013-01-01

    Coordination of operations with spatially and temporally shared resources, such as route segments, fixes, and runways, improves the efficiency of terminal airspace management. Problems in this category are, in general, computationally difficult compared to conventional scheduling problems. This paper presents a fast time algorithm formulation using a non-dominated sorting genetic algorithm (NSGA). It was first applied to a test problem introduced in existing literature. An experiment with a test problem showed that new methods can solve the 20 aircraft problem in fast time with a 65% or 440 second delay reduction using shared departure fixes. In order to test its application in a more realistic and complicated problem, the NSGA algorithm was applied to a problem in LAX terminal airspace, where interactions between 28% of LAX arrivals and 10% of LAX departures are resolved by spatial separation in current operations, which may introduce unnecessary delays. In this work, three types of separations - spatial, temporal, and hybrid separations - were formulated using the new algorithm. The hybrid separation combines both temporal and spatial separations. Results showed that although temporal separation achieved less delay than spatial separation with a small uncertainty buffer, spatial separation outperformed temporal separation when the uncertainty buffer was increased. Hybrid separation introduced much less delay than both spatial and temporal approaches. For a total of 15 interacting departures and arrivals, when compared to spatial separation, the delay reduction of hybrid separation varied between 11% or 3.1 minutes and 64% or 10.7 minutes corresponding to an uncertainty buffer from 0 to 60 seconds. Furthermore, as a comparison with the NSGA algorithm, a First-Come-First-Serve based heuristic method was implemented for the hybrid separation. Experiments showed that the results from the NSGA algorithm have 9% to 42% less delay than the heuristic method with varied uncertainty buffer sizes.

  8. Cancellation of spurious arrivals in Green's function extraction and the generalized optical theorem

    USGS Publications Warehouse

    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.

  9. A conflict analysis of 4D descent strategies in a metered, multiple-arrival route environment

    NASA Technical Reports Server (NTRS)

    Izumi, K. H.; Harris, C. S.

    1990-01-01

    A conflict analysis was performed on multiple arrival traffic at a typical metered airport. The Flow Management Evaluation Model (FMEM) was used to simulate arrival operations using Denver Stapleton's arrival route structure. Sensitivities of conflict performance to three different 4-D descent strategies (clear-idle Mach/Constant AirSpeed (CAS), constant descent angle Mach/CAS and energy optimal) were examined for three traffic mixes represented by those found at Denver Stapleton, John F. Kennedy and typical en route metering (ERM) airports. The Monte Carlo technique was used to generate simulation entry point times. Analysis results indicate that the clean-idle descent strategy offers the best compromise in overall performance. Performance measures primarily include susceptibility to conflict and conflict severity. Fuel usage performance is extrapolated from previous descent strategy studies.

  10. Marrying after arriving: The role of individuals' networks for immigrant choice of partner's origin.

    PubMed

    del Rey Poveda, Alberto; Vono de Vilhena, Daniela

    2014-03-01

    This paper analyses the impact of social networks on the transition to marriage among recently arrived, single, immigrants in Spain. Our hypothesis states that the existence of individual networks at the moment of arrival strongly influences partner selection. Using the 2007 Spanish National Immigration Survey we apply competing risk models to estimate the likelihood of endogamous or exogamous marriage, for men and women separately. The analysis shows that among immigrant men and women, the presence of relatives or friends from their home-country at the time of arrival increases the probability of marriage to a co-national. Correspondingly, immigrants who obtained Spanish citizenship before migrating present higher chances of intermarriage, as they are likely to have more contact with the host society. PMID:24796876

  11. Variation in climate warming along the migration route uncouples arrival and breeding dates

    E-print Network

    Laaksonen, Toni

    Variation in climate warming along the migration route uncouples arrival and breeding dates M A R K and at the breeding grounds. Here we show that migration and breeding times of a trans-Saharan migrant, the pied and at the breeding grounds. Because of differences in long-term temperature trends of short within-spring periods

  12. Analysis of delay reducing and fuel saving sequencing and spacing algorithms for arrival traffic

    NASA Technical Reports Server (NTRS)

    Neuman, Frank; Erzberger, Heinz

    1991-01-01

    The air traffic control subsystem that performs sequencing and spacing is discussed. The function of the sequencing and spacing algorithms is to automatically plan the most efficient landing order and to assign optimally spaced landing times to all arrivals. Several algorithms are described and their statistical performance is examined. Sequencing brings order to an arrival sequence for aircraft. First-come-first-served sequencing (FCFS) establishes a fair order, based on estimated times of arrival, and determines proper separations. Because of the randomness of the arriving traffic, gaps will remain in the sequence of aircraft. Delays are reduced by time-advancing the leading aircraft of each group while still preserving the FCFS order. Tightly spaced groups of aircraft remain with a mix of heavy and large aircraft. Spacing requirements differ for different types of aircraft trailing each other. Traffic is reordered slightly to take advantage of this spacing criterion, thus shortening the groups and reducing average delays. For heavy traffic, delays for different traffic samples vary widely, even when the same set of statistical parameters is used to produce each sample. This report supersedes NASA TM-102795 on the same subject. It includes a new method of time-advance as well as an efficient method of sequencing and spacing for two dependent runways.

  13. Modeling mixed retention and early arrivals in multidimensional heterogeneous media using an explicit Lagrangian scheme

    NASA Astrophysics Data System (ADS)

    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.

  14. Holographic Phase Transitions of P-wave Superconductors in Gauss-Bonnet Gravity with Back-reaction

    E-print Network

    Rong-Gen Cai; Zhang-Yu Nie; Hai-Qing Zhang

    2011-01-14

    We investigate the phase transitions of holographic p-wave superconductors in (4+1)-dimensional Einstein-Yang-Mills-Gauss-Bonnet theories, in a grand canonical ensemble. Turning on the back-reaction of the Yang-Mills field, it is found that the condensations of vector order parameter become harder if the Gauss-Bonnet coefficient grows up or the back-reaction becomes stronger. In particular, the vector order parameter exhibits the features of first order and second order phase transitions, while only the second order phase transition is observed in the probe limit. We discuss the roles that the Gauss-Bonnet term and the back-reaction play in changing the order of phase transition.

  15. Automated measurement of differential P and S times for imaging near-source Vp/Vs ratio with moving-window cross-correlation analysis

    NASA Astrophysics Data System (ADS)

    Kato, Aitaro; Taira, Taka'aki

    2014-05-01

    A high-resolution imaging of Vp/Vs ratio is crucial to understand fluid content in active faults and volcanoes. Lin & Shearer (2007, BSSA) recently developed a methodology to obtain near-source Vp/Vs ratios in individual similar earthquake clusters, based on differential P and S wave measurements. We here present an automated procedure to estimate differential P and S times by exploiting temporal properties of delayed time for pairs of seismograms with a moving-window cross-correlation analysis (e.g., Snieder, 2002, Phys. Rev. E; Niu et al. 2003, Nature). Our approach is based on the principle that the delayed time for the direct S wave differs from that for the direct P wave. After two waveforms are aligned by the direct P wave (i.e., differential P time), the temporal evolution of delayed time shows a step function and the onset time of its discontinuity corresponds to the arrival time of the direct S wave, in an ideal case. The offset of the step function represents the differential S-P time, and the differential S time is thus calculated from the differential P and S-P times. We perform a numerical experiment with the 3-D finite-difference code, SOFI3D (Bohlen, 2002, Computers & Geosciences) to address the effects of coda waves in the differential time measurement. We find that the differential S time measurement with the direct S-wave part is perturbed due to P coda, introducing a bias in the resulting Vp/Vs measurement. Our numerical experiment shows that the differential time measurement is more robust with the S coda. We apply our automated procedure for seismic data recorded at the Geysers geothermal field, California, and present a spatial variation of Vp/Vs ratio at this geothermal field.

  16. Estimated Moho Temperature from Observed Heat Flow and Comparison with P-Wave Velocity in the East Sea, Korea

    NASA Astrophysics Data System (ADS)

    Jung, W. Y.; Wood, W. T.

    2014-12-01

    We have estimated temperatures at the Moho surface by employing a published empirical relationship of Perry et al's work (JGR, doi:10.1029/2005JB003921) to the observed heat flow measurements in the East Sea (Sea of Japan), Korea. We assumed in our computation that the parameter values are all the same although the Perry et al's relationship between crustal thickness and heat flows to compute Moho temperature was derived for the Canadian Shield. For the heat flow data, we used the published global heat flow data (http://www.heatflow.und.edu) augmented with some recent heat flow measurements from Korea, and the LLN3_G3Dv3 for P-wave tomography model (JGR, doi:10.1029/2012JB009525). Preliminary results do not show a significant correlation between the computed Moho temperature and the P-wave velocity model perhaps due to uncertainty in the parameter values used in the computation as well as the empirical relation. An empirical relationship between the observed heat flow and the Moho temperature for the Canadian shield might be different for a backarec basin area like the East Sea, Korea. However, we noted that there exists a moderate negative correlation between the total crustal thickness and heat flow - less heat flows with increasing crustal thickness with a relation of Heat_Flow (mW/m2) = 205 - 18.3 * Crustal_Thickness (km). The modeled Moho temperature displays a trend of higher values (900o K -1400o K) from Japan toward the beneath of Yamato Basin and Rise in the NW direction, and beneath the Ulleung Basin area. Another higher Moho temperature (>1000o K) contour band is observed in the area north of Japan Basin, approximately centered along the 139.5o E.

  17. A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate Change

    PubMed Central

    Wilson, W. Herbert

    2013-01-01

    Using an 18-year dataset of arrival dates of 65 species of Maine migratory breeding birds, I take a deeper view of the data to ask questions about the shapes of the distribution. For each year, most species show a consistent right-skewed pattern of distribution, suggesting that selection is stronger against individuals that arrive too early compared to those that arrive later. Distributions are consistently leptokurtic, indicating a narrow window of optimal arrival dates. Species that arrive earlier in the spring show higher skewness and kurtosis values. Nectarivorous species showed more pronounced skewness. Wintering area did not explain patterns of skewness or kurtosis. Deviations from average temperatures and the North Atlantic Oscillation index explained little variation in skewness and kurtosis. When arrival date distributions are broken down into different medians (e.g., 5% median and 75% median), stronger correlations emerge for portions of the distribution that are adjacent, suggesting species fine-tune the progress of their migration. Interspecific correlations for birds arriving around the same time are stronger for earliest migrants (the 25% median) compared to the true median and the 75% median. PMID:24832806

  18. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  19. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  20. Transverse horizontal spatial coherence of deep arrivals at megameter ranges

    E-print Network

    Frandsen, Jannette B.

    Transverse horizontal spatial coherence of deep arrivals at megameter ranges Rex K. Andrew, Bruce M; accepted 10 November 2004 Predictions of transverse horizontal spatial coherence from path integral theory to about 1° in horizontal arrival angle variability using a simple, extended, spatially incoherent source

  1. 19 CFR 123.61 - Baggage arriving in baggage car.

    Code of Federal Regulations, 2010 CFR

    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....

  2. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  3. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  4. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  5. 19 CFR 123.61 - Baggage arriving in baggage car.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Baggage arriving in baggage car. 123.61 Section 123.61 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY CBP RELATIONS WITH CANADA AND MEXICO Baggage § 123.61 Baggage arriving in baggage car. An inward foreign manifest on Customs Form...

  6. 19 CFR 122.154 - Notice of arrival.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...DEPARTMENT OF THE TREASURY AIR COMMERCE REGULATIONS Flights to and From Cuba § 122.154 Notice of arrival. (a) Application. All aircraft entering the U.S. from Cuba must give advance notice of arrival, unless it is an Office of...

  7. 19 CFR 122.154 - Notice of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...DEPARTMENT OF THE TREASURY AIR COMMERCE REGULATIONS Flights to and From Cuba § 122.154 Notice of arrival. (a) Application. All aircraft entering the U.S. from Cuba must give advance notice of arrival, unless it is an Office of...

  8. 19 CFR 122.154 - Notice of arrival.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...DEPARTMENT OF THE TREASURY AIR COMMERCE REGULATIONS Flights to and From Cuba § 122.154 Notice of arrival. (a) Application. All aircraft entering the U.S. from Cuba must give advance notice of arrival, unless it is an Office of...

  9. 19 CFR 122.154 - Notice of arrival.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...DEPARTMENT OF THE TREASURY AIR COMMERCE REGULATIONS Flights to and From Cuba § 122.154 Notice of arrival. (a) Application. All aircraft entering the U.S. from Cuba must give advance notice of arrival, unless it is an Office of...

  10. 19 CFR 122.154 - Notice of arrival.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...DEPARTMENT OF THE TREASURY AIR COMMERCE REGULATIONS Flights to and From Cuba § 122.154 Notice of arrival. (a) Application. All aircraft entering the U.S. from Cuba must give advance notice of arrival, unless it is an Office of...

  11. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  12. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  13. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  14. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  15. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  16. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  17. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2010 CFR

    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...

  18. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  19. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 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...

  20. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...