Science.gov

Sample records for strike point position

  1. Strike Point Control on EAST Using an Isoflux Control Method

    NASA Astrophysics Data System (ADS)

    Xing, Zhe; Xiao, Bingjia; Luo, Zhengping; L. Walker, M.; A. Humphreys, D.

    2015-09-01

    For the advanced tokamak, the particle deposition and thermal load on the divertor is a big challenge. By moving the strike points on divertor target plates, the position of particle deposition and thermal load can be shifted. We could adjust the Poloidal Field (PF) coil current to achieve the strike point position feedback control. Using isoflux control method, the strike point position can be controlled by controlling the X point position. On the basis of experimental data, we establish relational expressions between X point position and strike point position. Benchmark experiments are carried out to validate the correctness and robustness of the control methods. The strike point position is successfully controlled following our command in the EAST operation. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2012GB105000 and 2014GB103000)

  2. Strike Point Control for the National Spherical Torus Experiment (NSTX)

    SciTech Connect

    Kolemen, E.; Gates, D. A.; Rowley, C. W.; Kasdin, N. J.; Kallman, J.; Gerhardt, S.; Soukhanovskii, V.; Mueller, D.

    2010-07-09

    This paper presents the first control algorithm for the inner and outer strike point position for a Spherical Torus (ST) fusion experiment and the performance analysis of the controller. A liquid lithium divertor (LLD) will be installed on NSTX which is believed to provide better pumping than lithium coatings on carbon PFCs. The shape of the plasma dictates the pumping rate of the lithium by channeling the plasma to LLD, where strike point location is the most important shape parameter. Simulations show that the density reduction depends on the proximity of strike point to LLD. Experiments were performed to study the dynamics of the strike point, design a new controller to change the location of the strike point to desired location and stabilize it. The most effective PF coils in changing inner and outer strike points were identified using equilibrium code. The PF coil inputs were changed in a step fashion between various set points and the step response of the strike point position was obtained. From the analysis of the step responses, PID controllers for the strike points were obtained and the controller was tuned experimentally for better performance. The strike controller was extended to include the outer-strike point on the inner plate to accommodate the desired low outer-strike points for the experiment with the aim of achieving "snowflake" divertor configuration in NSTX.

  3. Cellular nonlinear networks for strike-point localization at JET

    NASA Astrophysics Data System (ADS)

    Arena, P.; Fortuna, L.; Bruno, M.; Vagliasindi, G.; Murari, A.; Andrew, P.; Mazzitelli, G.

    2005-11-01

    At JET, the potential of fast image processing for real-time purposes is thoroughly investigated. Particular attention is devoted to smart sensors based on system on chip technology. The data of the infrared cameras were processed with a chip implementing a cellular nonlinear network (CNN) structure so as to support and complement the magnetic diagnostics in the real-time localization of the strike-point position in the divertor. The circuit consists of two layers of complementary metal-oxide semiconductor components, the first being the sensor and the second implementing the actual CNN. This innovative hardware has made it possible to determine the position of the maximum thermal load with a time resolution of the order of 30 ms. Good congruency has been found with the measurement from the thermocouples in the divertor, proving the potential of the infrared data in locating the region of the maximum thermal load. The results are also confirmed by JET magnetic codes, both those used for the equilibrium reconstructions and those devoted to the identification of the plasma boundary.

  4. Equilibrium and vertical-instability considerations for vertical strike-point shifts on the ITER divertor targets

    NASA Astrophysics Data System (ADS)

    Kolesnikov, R. A.; Bulmer, R. H.; LoDestro, L. L.; Casper, T. A.; Pitts, R. A.

    2013-08-01

    The study of operation with raised strike points on the first ITER divertor target plates is motivated by the need to gain experience with operation with strike points on tungsten (W) surfaces during the non-active phases (in the case of an initial carbon fibre composite (CFC)/W divertor); or (if ITER begins with a full-W divertor), to gain experience with plasma control and transients while operating with raised strike points to avoid damaging the baseline strike regions in preparation for the nuclear phase, and to provide a means for operation should damage occur in the baseline strike zone. For operation with raised strike points, we use the Corsica code to investigate the range of possible H- and L-mode equilibria, with emphasis on the maximum plasma current, achievable shapes, etc. With raised strike points the maximum achievable plasma current is close to 14 MA. The operating space (βp - li) for raised strike points has been studied. The size of the βp - li operating space shrinks (compared to using standard strike-point positions) at 14 MA. For 12 MA, however, the operating space is not affected when using raised strike points. For equilibria with elevated strike points (at roughly the CFC/W transitions, following the 2007 ITER Design Review) the vertical-instability growth-rates at high plasma current (14 MA) are somewhat high but are within the 20 s-1 which studies indicate are controllable in ITER. At lower currents (12 MA) in H-mode, the vertical-instability growth rates stay below 10.0 s-1 for most of βp - li space. At 12 MA in H-mode, multiple equilibria which meet our constraints have been found in overlapping regions of the βp - li operating space.

  5. Inertial Pointing and Positioning System

    NASA Technical Reports Server (NTRS)

    Yee, Robert (Inventor); Robbins, Fred (Inventor)

    1998-01-01

    An inertial pointing and control system and method for pointing to a designated target with known coordinates from a platform to provide accurate position, steering, and command information. The system continuously receives GPS signals and corrects Inertial Navigation System (INS) dead reckoning or drift errors. An INS is mounted directly on a pointing instrument rather than in a remote location on the platform for-monitoring the terrestrial position and instrument attitude. and for pointing the instrument at designated celestial targets or ground based landmarks. As a result. the pointing instrument and die INS move independently in inertial space from the platform since the INS is decoupled from the platform. Another important characteristic of the present system is that selected INS measurements are combined with predefined coordinate transformation equations and control logic algorithms under computer control in order to generate inertial pointing commands to the pointing instrument. More specifically. the computer calculates the desired instrument angles (Phi, Theta. Psi). which are then compared to the Euler angles measured by the instrument- mounted INS. and forms the pointing command error angles as a result of the compared difference.

  6. Patterned charring along the contact points of a metallic locket due to lightning strike.

    PubMed

    Adil, Md Tanveer; Rahman, Rumana; Das, Soumen

    2016-06-01

    Superficial cutaneous burns following lightning strike may vary in patterns ranging from linear burns, punctate burns, feathering burns, and thermal burns. Contact with an extrinsic object in the pathway of lightning current can lead to disastrous consequences. The lucky who survive may show bizarre and interesting burn patterns to tell their story. PMID:27398211

  7. Precise Point Positioning in the Airborne Mode

    NASA Astrophysics Data System (ADS)

    El-Mowafy, Ahmed

    2011-01-01

    The Global Positioning System (GPS) is widely used for positioning in the airborne mode such as in navigation as a supplementary system and for geo-referencing of cameras in mapping and surveillance by aircrafts and Unmanned Aerial Vehicles (UAV). The Precise Point Positioning (PPP) approach is an attractive positioning approach based on processing of un-differenced observations from a single GPS receiver. It employs precise satellite orbits and satellite clock corrections. These data can be obtained via the internet from several sources, e.g. the International GNSS Service (IGS). The data can also broadcast from satellites, such as via the LEX signal of the new Japanese satellite system QZSS. The PPP can achieve positioning precision and accuracy at the sub-decimetre level. In this paper, the functional and stochastic mathematical modelling used in PPP is discussed. Results of applying the PPP method in an airborne test using a small fixed-wing aircraft are presented. To evaluate the performance of the PPP approach, a reference trajectory was established by differential positioning of the same GPS observations with data from a ground reference station. The coordinate results from the two approaches, PPP and differential positioning, were compared and statistically evaluated. For the test at hand, positioning accuracy at the cm-to-decimetre was achieved for latitude and longitude coordinates and doubles that value for height estimation.

  8. Point Positioning Service for Natural Hazard Monitoring

    NASA Astrophysics Data System (ADS)

    Bar-Sever, Y. E.

    2014-12-01

    In an effort to improve natural hazard monitoring, JPL has invested in updating and enlarging its global real-time GNSS tracking network, and has launched a unique service - real-time precise positioning for natural hazard monitoring, entitled GREAT Alert (GNSS Real-Time Earthquake and Tsunami Alert). GREAT Alert leverages the full technological and operational capability of the JPL's Global Differential GPS System [www.gdgps.net] to offer owners of real-time dual-frequency GNSS receivers: Sub-5 cm (3D RMS) real-time, absolute positioning in ITRF08, regardless of location Under 5 seconds turnaround time Full covariance information Estimates of ancillary parameters (such as troposphere) optionally provided This service enables GNSS networks operators to instantly have access to the most accurate and reliable real-time positioning solutions for their sites, and also to the hundreds of participating sites globally, assuring inter-consistency and uniformity across all solutions. Local authorities with limited technical and financial resources can now access to the best technology, and share environmental data to the benefit of the entire pacific region. We will describe the specialized precise point positioning techniques employed by the GREAT Alert service optimized for natural hazard monitoring, and in particular Earthquake monitoring. We address three fundamental aspects of these applications: 1) small and infrequent motion, 2) the availability of data at a central location, and 3) the need for refined solutions at several time scales

  9. Striking responsibilities.

    PubMed

    Brecher, R

    1985-06-01

    It is commonly held that National Health Service (NHS) workers are under a moral obligation not to go on strike, because doing so might well result in people's dying. Unless sainthood is demanded, however, this position is untenable: indeed, those most vociferously pursuing it are often those who bear the greatest responsibility, on their own grounds, for needless death and suffering. PMID:4009635

  10. Studying the Formation Mechanism of New Ground Strike Points in Natural Negative Cloud-to-Ground Lightning

    NASA Astrophysics Data System (ADS)

    Campos, L. Z. D. S.; Cummins, K. L.; Pinto, O., Jr.

    2015-12-01

    Data from three-dimensional VHF mapping, high-speed video and slow electric field antenna of multiple ground contact flashes (MGCFs) have been analyzed in an attempt to characterize the process through which new ground terminations in natural lightning are formed. The three-dimensional VHF mapping data (obtained by a Lightning Mapping Array, LMA) provided valuable information on the processes that occurred inside the cloud during the interval between strokes. Detailed case studies of over 30 MGCFs observed in the vicinity of a wind farm in Kansas, USA, have allowed the identification and qualitative description of three mechanisms through which a given flash may touch ground at different locations. In events of Type I, the dart leader that initiates the subsequent stroke starts in the original channel and then diverges from the original path of the first stroke, ionizing a new channel and reaching ground at a different location. In high-speed video records, these events eventually have their "diverging" point visible below cloud base and their strike locations are separated by a few hundreds of meters. Type II, on the other hand, comprises flashes in which the subsequent stroke is initiated in an in-cloud branch that is farther from the inception region of the first return stroke, moving in another direction and touching ground at farther distances (up to more than 10 km from the initial strike location). Finally, Type III flashes typically gave rise to several return strokes, each with different ground strike points. Stepped leaders initiated in the same general region in the cloud give rise to these strokes with typical interstroke intervals below 100 milliseconds but no common channel branches among them could be conclusively identified. Representative events of each type are discussed in detail.

  11. Precise Point Positioning with Partial Ambiguity Fixing.

    PubMed

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate. PMID:26067196

  12. Precise Point Positioning with Partial Ambiguity Fixing

    PubMed Central

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate. PMID:26067196

  13. Robot positioning based on point-to-point motion capability

    SciTech Connect

    Park, Y. S.; Cho, H. S.; Koh, K. C.

    2000-03-20

    This paper presents an optimal search method for determining the base location of a robot manipulator so that the robot can have a designated point-to-point (PTP) motion capabilities. Based on the topological characterization of the manipulator workspace and the definitions of various p-connectivity, a computational method is developed for enumerating various PTP motion capabilities into quantitative cost functions. Then an unconstrained search by minimizing the cost function yields the task feasible location of the robot base. This methodology is useful for placement of mobile manipulators and robotic workcell layout design.

  14. Coseismic strike slip at a point during the last four earthquakes on the Wellington fault near Wellington, New Zealand

    NASA Astrophysics Data System (ADS)

    Little, Timothy A.; van Dissen, Russ; Rieser, Uwe; Smith, Euan G. C.; Langridge, Rob M.

    2010-05-01

    We analyze progressively displaced late Quaternary (<12 ka) fluvial terraces along the Wellington fault, near Wellington, New Zealand. Optically stimulated luminescence dating indicates that degradational terraces were produced at a rate of about one terrace per 1000 years, similar to the rate of earthquake surface rupturing. Along the Hutt River near Te Marua, we measured the strike slip of 15 terrace risers and paleochannels on the lowest 8 of these terraces, of Holocene age. The river, after earthquakes, was generally capable of smoothing its faulted riverbanks. The dextral offsets appear to fall into several groupings that record slip accumulation during the last four earthquakes. We calculate a mean single-event slip of 5.0 ± 0.24 m (95% confidence) with an RMS scatter (1σ) of slips about the mean of ±1.5 m. The coefficient of variation (CV) of single-event slip is thus 0.30. This CV is slightly less than a recently compiled global average for point measurements on strike-slip faults, suggesting that the southernmost Wellington fault has behaved in a more nearly characteristic way. We speculate that recent large earthquake ruptures have been bounded on their southern end by the Wellington fault's offshore fault termination and perhaps on their northern end by a ˜2 km wide releasing step over. Such persistent sources of rupture arrest might have led to a relative uniformity of rupture dimensions and slip amounts. We infer a late Holocene dextral slip rate of ≥4.5 ± 0.4 mm/yr (1σ) and <8.2 mm/yr, and a mean earthquake recurrence interval of ˜610-1100 years.

  15. Investigation on the pinch point position in heat exchangers

    NASA Astrophysics Data System (ADS)

    Pan, Lisheng; Shi, Weixiu

    2016-06-01

    The pinch point is important for analyzing heat transfer in thermodynamic cycles. With the aim to reveal the importance of determining the accurate pinch point, the research on the pinch point position is carried out by theoretical method. The results show that the pinch point position depends on the parameters of the heat transfer fluids and the major fluid properties. In most cases, the pinch point locates at the bubble point for the evaporator and the dew point for the condenser. However, the pinch point shifts to the supercooled liquid state in the near critical conditions for the evaporator. Similarly, it shifts to the superheated vapor state with the condensing temperature approaching the critical temperature for the condenser. It even can shift to the working fluid entrance of the evaporator or the supercritical heater when the heat source fluid temperature is very high compared with the absorbing heat temperature. A wrong position for the pinch point may generate serious mistake. In brief, the pinch point should be founded by the iterative method in all conditions rather than taking for granted.

  16. Physician strikes.

    PubMed

    Thompson, Stephen L; Salmon, J Warren

    2014-11-01

    Throughout medical history, physicians have rarely formed unions and/or carried out strikes. In a profession faced with the turmoil of health reform and increasing pressure to change their practices and lifestyles, will physicians resort to unionization for collective bargaining, and will a strike weapon be used to fight back against the array of corporate and government powers involved in the transformation of the American health-care system? This article examines the question of whether there could be such a thing as an ethical physician strike. Although physicians have not historically used collective bargaining or the strike weapon, the rapidly changing practice environment in the United States might push physicians and other health-care professionals toward unionization. This article considers the ethical questions that would arise if physicians started taking advantage of labor laws, and it lays out criteria for an ethical strike. PMID:25367473

  17. Lightning Often Strikes Twice

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Contrary to popular misconception, lightning often strikes the same place twice. Certain conditions are just ripe for a bolt of electricity to come zapping down; and a lightning strike is powerful enough to do a lot of damage wherever it hits. NASA created the Accurate Location of Lightning Strikes technology to determine the ground strike point of lightning and prevent electrical damage in the immediate vicinity of the Space Shuttle launch pads at Kennedy Space Center. The area surrounding the launch pads is enmeshed in a network of electrical wires and components, and electronic equipment is highly susceptible to lightning strike damage. The accurate knowledge of the striking point is important so that crews can determine which equipment or system needs to be retested following a strike. Accurate to within a few yards, this technology can locate a lightning strike in the perimeter of the launch pad. As an added bonus, the engineers, then knowing where the lightning struck, can adjust the variables that may be attracting the lightning, to create a zone that will be less susceptible to future strikes.

  18. Radial arm strike rail

    DOEpatents

    McKeown, Mark H.; Beason, Steven C.

    1991-01-01

    The radial arm strike rail assembly is a system for measurement of bearings, directions, and stereophotography for geologic mapping, particularly where magnetic compasses are not appropriate. The radial arm, pivoting around a shaft axis, provides a reference direction determination for geologic mapping and bearing or direction determination. The centerable and levelable pedestal provide a base for the radial arm strike rail and the telescoping camera pedestal. The telescoping feature of the radial arm strike rail allows positioning the end of the rail for strike direction or bearing measurement with a goniometer.

  19. Obtaining Glenoid Positioning Data from Scapular Palpable Points In Vitro

    PubMed Central

    Trafimow, Jordan H.; Aruin, Alexander S.

    2013-01-01

    Both clinical and biomechanical problems affecting the shoulder joint suggest that investigators should study force transmission into and out from the scapula. To analyze force transmission between the humeral head and the glenoid, one must know the position of the glenoid. Studies have analyzed the position of the scapula from the positions of three palpable points, but the position of the glenoid relative to three palpable points has not been studied. Dry scapulae (N = 13) were subjected to X-rays and a critical angle, Θ (which relates the plane determined by the three palpable points on the scapula to a plane containing the glenoid center and the first two palpable points) was calculated. The mean value for Θ was 28.5 ± 5.60 degrees. The obtained Θ allows us to determine the position of the glenoid from three palpable points. This information could be used in calculation of forces across the shoulder joint, which in turn would allow optimizing the choice of strengthening exercises. PMID:23653863

  20. Striking Clepsydras

    NASA Astrophysics Data System (ADS)

    Nam, Moon-Hyon

    The term "Striking Clepsydra" is a shortened translation of the Korean name Jagyeongnu (自擊漏, tzu-chi lou in Chinese, literally "automatic-striking water-clock"). It was given to the two monumental time-keeping installations built by chief court engineer Yeong-sil Jang in AD 1432-38 under King Sejong (r. AD 1418-50) of the Joseon dynasty (1392-1910) in Seoul. These were housed separately in the Gyeongbok palace complex as major installations of the Royal Observatory Ganuidae equipped during 1432-38. One was the Striking Palace Clepsydra Borugangnu that was employed as the standard time-keeper from 1434, and the other was the Striking Heavenly Clepsydra Heumgyeonggangnu that was put into use not only as the symbol of Neo-Confucian ideology from 1438, but also as a demonstrational orrery and time-keeper. These were restored several times through the dynasty after loss by fires and warfare, and clepsydra-making technologies were succeeded by the development of armillary clocks in 1669. The National Palace Museum of Korea recreated the 1434 Striking Palace Clepsydra of King Sejong, and the replica was installed for permanent exhibition from November 2007.

  1. Generic parabolic points are isolated in positive characteristic

    NASA Astrophysics Data System (ADS)

    Lindahl, Karl-Olof; Rivera-Letelier, Juan

    2016-05-01

    We study analytic germs in one variable with a parabolic fixed point at the origin, over an ultrametric ground field of positive characteristic. It is conjectured that for such a germ the origin is isolated as a periodic point. Our main result is an affirmative solution of this conjecture in the case of a generic germ with a prescribed multiplier. The genericity condition is explicit: the power series is minimally ramified, i.e. the degree of the first nonlinear term of each of its iterates is as small as possible. Our main technical result is a computation of the first significant terms of a minimally ramified power series. From this we obtain a lower bound for the norm of nonzero periodic points, from which we deduce our main result. As a by-product we give a new and self-contained proof of a characterization of minimally ramified power series in terms of the iterative residue.

  2. Code Single Point Positioning Using Nominal GNSS Constellations (Future Perception)

    NASA Astrophysics Data System (ADS)

    Farah, A. M. A.

    Global Navigation Satellite Systems (GNSS) have an endless number of applications in industry, science, military, transportation and recreation & sports. Two systems are currently in operation, namely GPS (the USA Global Positioning System) and GLONASS (the Russian GLObal NAvigation Satellite System), and a third is planned, the European satellite navigation system GALILEO. The potential performance improvements achievable through combining these systems could be significant and expectations are high. The need is inevitable to explore the future of positioning from different nominal constellations. In this research paper, Bernese 5.0 software could be modified to simulate and process GNSS observations from three different constellations (GPS, GLONASS and Galileo) using different combinations. This study presents results of code single point positioning for five stations using the three constellations and different combinations.

  3. GPS and Glonass Combined Static Precise Point Positioning (ppp)

    NASA Astrophysics Data System (ADS)

    Pandey, D.; Dwivedi, R.; Dikshit, O.; Singh, A. K.

    2016-06-01

    With the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs), satellite navigation is undergoing drastic changes. Presently, more than 70 satellites are already available and nearly 120 more satellites will be available in the coming years after the achievement of complete constellation for all four systems- GPS, GLONASS, Galileo and BeiDou. The significant improvement in terms of satellite visibility, spatial geometry, dilution of precision and accuracy demands the utilization of combining multi-GNSS for Precise Point Positioning (PPP), especially in constrained environments. Currently, PPP is performed based on the processing of only GPS observations. Static and kinematic PPP solutions based on the processing of only GPS observations is limited by the satellite visibility, which is often insufficient for the mountainous and open pit mines areas. One of the easiest options available to enhance the positioning reliability is to integrate GPS and GLONASS observations. This research investigates the efficacy of combining GPS and GLONASS observations for achieving static PPP solution and its sensitivity to different processing methodology. Two static PPP solutions, namely standalone GPS and combined GPS-GLONASS solutions are compared. The datasets are processed using the open source GNSS processing environment gLAB 2.2.7 as well as magicGNSS software package. The results reveal that the addition of GLONASS observations improves the static positioning accuracy in comparison with the standalone GPS point positioning. Further, results show that there is an improvement in the three dimensional positioning accuracy. It is also shown that the addition of GLONASS constellation improves the total number of visible satellites by more than 60% which leads to the improvement of satellite geometry represented by Position Dilution of Precision (PDOP) by more than 30%.

  4. Positive deconvolution for superimposed extended source and point sources

    NASA Astrophysics Data System (ADS)

    Giovannelli, J.-F.; Coulais, A.

    2005-08-01

    The paper deals with the construction of images from visibilities acquired using aperture synthesis instruments: Fourier synthesis, deconvolution, and spectral interpolation/extrapolation. Its intended application is to specific situations in which the imaged object possesses two superimposed components: (i) an extended component together with (ii) a set of point sources. It is also specifically designed to the case of positive maps, and accounts for a known support. Its originality lies within joint estimation of the two components, coherently with data, properties of each component, positivity and possible support. We approach the subject as an inverse problem within a regularization framework: a regularized least-squares criterion is specifically proposed and the estimated maps are defined as its minimizer. We have investigated several options for the numerical minimization and we propose a new efficient algorithm based on augmented Lagrangian. Evaluation is carried out using simulated and real data (from radio interferometry) demonstrating the capability to accurately separate the two components.

  5. Assessing the Accuracy of the Precise Point Positioning Technique

    NASA Astrophysics Data System (ADS)

    Bisnath, S. B.; Collins, P.; Seepersad, G.

    2012-12-01

    The Precise Point Positioning (PPP) GPS data processing technique has developed over the past 15 years to become a standard method for growing categories of positioning and navigation applications. The technique relies on single receiver point positioning combined with the use of precise satellite orbit and clock information and high-fidelity error modelling. The research presented here uniquely addresses the current accuracy of the technique, explains the limits of performance, and defines paths to improvements. For geodetic purposes, performance refers to daily static position accuracy. PPP processing of over 80 IGS stations over one week results in few millimetre positioning rms error in the north and east components and few centimetres in the vertical (all one sigma values). Larger error statistics for real-time and kinematic processing are also given. GPS PPP with ambiguity resolution processing is also carried out, producing slight improvements over the float solution results. These results are categorised into quality classes in order to analyse the root error causes of the resultant accuracies: "best", "worst", multipath, site displacement effects, satellite availability and geometry, etc. Also of interest in PPP performance is solution convergence period. Static, conventional solutions are slow to converge, with approximately 35 minutes required for 95% of solutions to reach the 20 cm or better horizontal accuracy. Ambiguity resolution can significantly reduce this period without biasing solutions. The definition of a PPP error budget is a complex task even with the resulting numerical assessment, as unlike the epoch-by-epoch processing in the Standard Position Service, PPP processing involving filtering. An attempt is made here to 1) define the magnitude of each error source in terms of range, 2) transform ranging error to position error via Dilution Of Precision (DOP), and 3) scale the DOP through the filtering process. The result is a deeper

  6. Precise Point Positioning Based on BDS and GPS Observations

    NASA Astrophysics Data System (ADS)

    Gao, ZhouZheng; Zhang, Hongping; Shen, Wenbin

    2014-05-01

    BeiDou Navigation Satellite System (BDS) has obtained the ability applying initial navigation and precise point services for the Asian-Pacific regions at the end of 2012 with the constellation of 5 Geostationary Earth Orbit (GEO), 5 Inclined Geosynchronous Orbit (IGSO) and 4 Medium Earth Orbit (MEO). Till 2020, it will consist with 5 GEO, 3 IGSO and 27 MEO, and apply global navigation service similar to GPS and GLONASS. As we known, GPS precise point positioning (PPP) is a powerful tool for crustal deformation monitoring, GPS meteorology, orbit determination of low earth orbit satellites, high accuracy kinematic positioning et al. However, it accuracy and convergence time are influenced by the quality of pseudo-range observations and the observing geometry between user and Global navigation satellites system (GNSS) satellites. Usually, it takes more than 30 minutes even hours to obtain centimeter level position accuracy for PPP while using GPS dual-frequency observations only. In recent years, many researches have been done to solve this problem. One of the approaches is smooth pseudo-range by carrier-phase observations to improve pseudo-range accuracy. By which can improve PPP initial position accuracy and shorten PPP convergence time. Another sachems is to change position dilution of precision (PDOP) with multi-GNSS observations. Now, BDS has the ability to service whole Asian-Pacific regions, which make it possible to use GPS and BDS for precise positioning. In addition, according to researches on GNSS PDOP distribution, BDS can improve PDOP obviously. Therefore, it necessary to do some researches on PPP performance using both GPS observations and BDS observations, especially in Asian-Pacific regions currently. In this paper, we focus on the influences of BDS to GPS PPP mainly in three terms including BDS PPP accuracy, PDOP improvement and convergence time of PPP based on GPS and BDS observations. Here, the GPS and BDS two-constellation data are collected from

  7. Local troposphere augmentation for real-time precise point positioning

    NASA Astrophysics Data System (ADS)

    Shi, Junbo; Xu, Chaoqian; Guo, Jiming; Gao, Yang

    2014-12-01

    The IGS real-time service (RTS) enables real-time precise point positioning (PPP) at a global scale. A long convergence time however is still a challenging factor. In order to reduce the convergence time, external troposphere corrections could be introduced to remove the troposphere effects on the coordinate solution. This paper proposes the use of a local troposphere model to augment real-time PPP. First, undifferenced observations from a network of multiple stations are processed to estimate the station-based troposphere zenith wet delay (ZWD). A set of local troposphere fitting coefficients are then derived using a proposed optimal fitting model. Finally, the determined troposphere fitting coefficients are broadcast to users to reduce the convergence time in the user solution. A continuous operating reference station (CORS) network is utilized to assess the performance of the proposed approach under quiet and active troposphere conditions. The numerical results show that the overall fitting precisions of the local troposphere model can reach 1.42 and 1.05 cm under the two troposphere conditions. The convergence time of the positioning solutions, especially the height solution, can be greatly reduced using the local troposphere model. The horizontal accuracy of 9.2 cm and the vertical accuracy of 10.1 cm are obtainable under the quiet troposphere condition after 20 min of initialization time, compared to the 14.7 cm horizontal and 21.5 cm vertical accuracies in the conventional troposphere estimation approach. Moreover, the horizontal accuracies of 13.0 cm and the vertical accuracies of 12.4 cm have also been obtained after 20 min under the active troposphere condition.

  8. Deterministic and Stochastic Receiver Clock Modeling in Precise Point Positioning

    NASA Astrophysics Data System (ADS)

    Orliac, E.; Dach, R.; Wang, K.; Rothacher, M.; Voithenleitner, D.; Hugentobler, U.; Heinze, M.; Svehla, D.

    2012-04-01

    The traditional GNSS (Global Navigation Satellite System) data analysis assumes an independent set of clock corrections for each epoch. This introduces a huge number of parameters that are highly correlated with station height and troposphere parameters. If the number of clock parameters can be reduced, the GNSS processing procedure may be stabilized. Experiments with kinematic solutions for stations equipped with H-Maser clocks have confirmed this. On the other hand, static coordinates do not significantly benefit from changing the strategy in handling the clock parameter. In the current GNSS constellation only GIOVE-B and the GPS Block IIF satellite clocks seem to be good enough to be modeled instead of freely estimated for each epoch without losing accuracy at the level of phase measurements. With the Galileo constellation this will change in future. In this context, ESA (European Space Agency) funded a project on "Satellite and Station Clock Modelling for GNSS". In the frame of this project, various deterministic and stochastic clock models have been evaluated, implemented and assessed for both, station and satellite clocks. In this paper we focus on the impact of modeling the receiver clock in the processing of GNSS data in static and kinematic precise point positioning (PPP) modes. Initial results show that for stations connected to an H-Maser clock the stability of the vertical position for kinematic PPP could be improved by up to 60%. The impact of clock modeling on the estimation of troposphere parameters is also investigated, along with the role of the tropospheric modeling itself, by testing various sampling rates and relative constraints for the troposphere parameters. Finally, we investigate the convergence time of PPP when deterministic or stochastic clock modeling is applied to the receiver clock.

  9. GLONASS ionosphere-free ambiguity resolution for precise point positioning

    NASA Astrophysics Data System (ADS)

    Banville, Simon

    2016-05-01

    Current GLONASS satellites transmit signals based on the frequency division multiple access (FDMA) technology. Due to equipment delays occurring within GNSS receivers, GLONASS carrier phase and code observations are contaminated by inter-frequency biases. As a consequence, GLONASS ambiguity parameters in long-baseline processing are typically estimated as float values. In this paper, a strategy is investigated which benefits from the frequency spacing of GLONASS frequencies on the L1 and L2 bands, allowing for an ionosphere-free ambiguity with a wavelength of approximately 5 cm to be defined; therefore, avoiding the problematic wide-lane ambiguity resolution. Based on 12 independent baselines with a mean inter-station distance of about 850 km over a 1-week period, it is demonstrated that close to 95 % of the estimated double-differenced ionosphere-free ambiguities are within 0.15 cycles of an integer, thereby suggesting that long-baseline ambiguity resolution can be achieved for GLONASS. Applying between-station ambiguity constraints in precise point positioning (PPP) solutions was found to improve longitudinal repeatability in static mode by more than 20 % for sessions between 2 and 6 h in duration. In kinematic mode, only limited improvements were made to the initial convergence period since the short wavelength of GLONASS ionosphere-free ambiguities requires the solution to be nearly converged before successful ambiguity resolution can be achieved.

  10. Precise Point Positioning Using Triple GNSS Constellations in Various Modes

    PubMed Central

    Afifi, Akram; El-Rabbany, Ahmed

    2016-01-01

    This paper introduces a new dual-frequency precise point positioning (PPP) model, which combines the observations from three different global navigation satellite system (GNSS) constellations, namely GPS, Galileo, and BeiDou. Combining measurements from different GNSS systems introduces additional biases, including inter-system bias and hardware delays, which require rigorous modelling. Our model is based on the un-differenced and between-satellite single-difference (BSSD) linear combinations. BSSD linear combination cancels out some receiver-related biases, including receiver clock error and non-zero initial phase bias of the receiver oscillator. Forming the BSSD linear combination requires a reference satellite, which can be selected from any of the GPS, Galileo, and BeiDou systems. In this paper three BSSD scenarios are tested; each considers a reference satellite from a different GNSS constellation. Natural Resources Canada’s GPSPace PPP software is modified to enable a combined GPS, Galileo, and BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets collected at four different IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the International GNSS Service Multi-GNSS Experiment (IGS-MGEX) network are used to correct the GPS, Galileo, and BeiDou measurements in the post-processing PPP mode. A real-time PPP solution is also obtained, which is referred to as RT-PPP in the sequel, through the use of the IGS real-time service (RTS) for satellite orbit and clock corrections. However, only GPS and Galileo observations are used for the RT-PPP solution, as the RTS-IGS satellite products are not presently available for BeiDou system. All post-processed and real-time PPP solutions are compared with the traditional un-differenced GPS-only counterparts. It is shown that combining the GPS, Galileo, and BeiDou observations in the post-processing mode improves the PPP convergence

  11. Precise Point Positioning Using Triple GNSS Constellations in Various Modes.

    PubMed

    Afifi, Akram; El-Rabbany, Ahmed

    2016-01-01

    This paper introduces a new dual-frequency precise point positioning (PPP) model, which combines the observations from three different global navigation satellite system (GNSS) constellations, namely GPS, Galileo, and BeiDou. Combining measurements from different GNSS systems introduces additional biases, including inter-system bias and hardware delays, which require rigorous modelling. Our model is based on the un-differenced and between-satellite single-difference (BSSD) linear combinations. BSSD linear combination cancels out some receiver-related biases, including receiver clock error and non-zero initial phase bias of the receiver oscillator. Forming the BSSD linear combination requires a reference satellite, which can be selected from any of the GPS, Galileo, and BeiDou systems. In this paper three BSSD scenarios are tested; each considers a reference satellite from a different GNSS constellation. Natural Resources Canada's GPSPace PPP software is modified to enable a combined GPS, Galileo, and BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets collected at four different IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the International GNSS Service Multi-GNSS Experiment (IGS-MGEX) network are used to correct the GPS, Galileo, and BeiDou measurements in the post-processing PPP mode. A real-time PPP solution is also obtained, which is referred to as RT-PPP in the sequel, through the use of the IGS real-time service (RTS) for satellite orbit and clock corrections. However, only GPS and Galileo observations are used for the RT-PPP solution, as the RTS-IGS satellite products are not presently available for BeiDou system. All post-processed and real-time PPP solutions are compared with the traditional un-differenced GPS-only counterparts. It is shown that combining the GPS, Galileo, and BeiDou observations in the post-processing mode improves the PPP convergence

  12. Single-frequency precise point positioning: an analytical approach

    NASA Astrophysics Data System (ADS)

    Sterle, Oskar; Stopar, Bojan; Pavlovčič Prešeren, Polona

    2015-08-01

    An analytical approach to single-frequency precise point positioning (PPP) is discussed in this paper. To obtain highest precision results, all biases must be eliminated or modelled to centimetre level. The use of the GRAPHIC ionosphere-free linear combination that is based on single-frequency phase and code observations eliminates the ionosphere bias; however, the rank deficient Gauss-Markov model is obtained. We explicitly determine rank deficiency of a Gauss-Markov model as a number of all ambiguity clusters, each of them defined as a set of all ambiguities overlapping in time. On the basis of S-transformation we prove that the single-frequency PPP represents an unbiased estimator for station coordinates and troposphere parameters, while it presents a biased estimator for ambiguities and receiver-clock error parameters. Additionally we describe the estimable parameters in each ambiguity cluster as the differences between ambiguity parameters and the sum of receiver-clock parameters with one of the ambiguities. We also show that any other particular solution on the basis of S-transformation is obtained only when the common least-squares estimation in single step is applied. The recursive least-squares estimation with parameter pre-elimination only determines the vector of unknowns as possible to transform through S-transformation, whereas the same does not hold for the cofactor matrix of unknowns. For a case study, we present our method on GPS data from 19 permanent stations (14 IGS and 5 EPN) in Europe, for 89 consecutive days in the beginning of 2013. The static case study revealed the precision of daily coordinates as 7.6, 11.7 and 19.6 mm for , and , respectively. The accuracies of the , and components were determined as 6.9, 13.5 and 31.4 mm, respectively, and were calculated using the Helmert transformation of weighted-mean daily single-frequency PPP and IGb08 coordinates. The estimated convergence times were relatively diverse, expanding from 1.75 h (CAGL

  13. Impact of selected troposphere models on Precise Point Positioning convergence

    NASA Astrophysics Data System (ADS)

    Kalita, Jakub; Rzepecka, Zofia

    2016-04-01

    The Precise Point Positioning (PPP) absolute method is currently intensively investigated in order to reach fast convergence time. Among various sources that influence the convergence of the PPP, the tropospheric delay is one of the most important. Numerous models of tropospheric delay are developed and applied to PPP processing. However, with rare exceptions, the quality of those models does not allow fixing the zenith path delay tropospheric parameter, leaving difference between nominal and final value to the estimation process. Here we present comparison of several PPP result sets, each of which based on different troposphere model. The respective nominal values are adopted from models: VMF1, GPT2w, MOPS and ZERO-WET. The PPP solution admitted as reference is based on the final troposphere product from the International GNSS Service (IGS). The VMF1 mapping function was used for all processing variants in order to provide capability to compare impact of applied nominal values. The worst case initiates zenith wet delay with zero value (ZERO-WET). Impact from all possible models for tropospheric nominal values should fit inside both IGS and ZERO-WET border variants. The analysis is based on data from seven IGS stations located in mid-latitude European region from year 2014. For the purpose of this study several days with the most active troposphere were selected for each of the station. All the PPP solutions were determined using gLAB open-source software, with the Kalman filter implemented independently by the authors of this work. The processing was performed on 1 hour slices of observation data. In addition to the analysis of the output processing files, the presented study contains detailed analysis of the tropospheric conditions for the selected data. The overall results show that for the height component the VMF1 model outperforms GPT2w and MOPS by 35-40% and ZERO-WET variant by 150%. In most of the cases all solutions converge to the same values during first

  14. Should junior doctors strike?

    PubMed

    Toynbee, Mark; Al-Diwani, Adam Aj; Clacey, Joe; Broome, Matthew R

    2016-03-01

    An impasse in negotiations between the Department of Health (DoH) and the British Medical Association in November this year led to an overwhelming vote for industrial action (IA) by junior doctors. At the time of writing, a last minute concession by DoH led to a deferment of IA to allow further negotiations mediated by the Advisory, Conciliation and Arbitration Service. However, IA by junior doctors remains a possibility if these negotiations stall again. Would the proposed action be ethically justifiable? Furthermore, is IA by doctors ever ethically defendable? Building on previous work, we explore important ethical considerations for doctors considering IA. The primary moral objection to doctors striking is often claimed to be risk of harm to patients. Other common arguments against IA by doctors include breaching their vocational responsibilities and possible damage to their relationship with patients and the public in general. These positions are in turn countered by claims of a greater long-term good and the legal and moral rights of employees to strike. Absolute restrictions appear to be hard to justify in the modern context, as does an unrestricted right to IA. We review these arguments, find that some common moral objections to doctors striking may be less relevant to the current situation, that a stronger contemporary objection to IA might be from a position of social justice and suggest criteria for ethically permissible doctor IA. PMID:26758366

  15. Three-Point Gear/Lead Screw Positioning

    NASA Technical Reports Server (NTRS)

    Calco, Frank S.

    1993-01-01

    Triple-ganged-lead-screw positioning mechanism drives movable plate toward or away from fixed plate and keeps plates parallel to each other. Designed for use in tuning microwave resonant cavity. Other potential applications include adjustable bed plates and cantilever tail stocks in machine tools, adjustable platforms for optical equipment, and lifting platforms.

  16. Effect of different head positions on the jaw closing point during tapping movements.

    PubMed

    Yamamoto, T; Nishigawa, K; Bando, E; Hosoki, M

    2009-01-01

    This study aimed to investigate the effects of different head positions on jaw closing points during tapping movements. The jaw movements of 20 adult volunteers were assessed using a new jaw-tracking device. All subjects had stable maximal intercuspation with their natural dentitions. The subjects were asked to seat on a dental chair with their head upright, and tapping movements were recorded for 5 s without any further instructions. After the chair was reclined to the horizontal position, tapping movements were also recorded with the head in the supine position. The location of the tapping point was defined as the jaw position which was the most closed to the maximum intercuspal position during each tapping stroke. Fifteen tapping points were obtained from the upright and supine head positions of each subject. Six-hundred tapping points were compared to evaluate the effects of different head positions. With the head upright, tapping points were relatively stable and close to the jaw position at the maximum intercuspation. However, in the supine position, tapping points varied widely and shifted forward. The average distance between the positions of the incisal point at the maximum intercuspation and at the tapping points was 0.11 mm (SD, 0.10) in the upright position and 0.30 mm (SD, 0.08) in the supine position. A Wilcoxon signed rank test showed a significant difference (P < 0.01) between these distances. We conclude that tapping points shift anteriorly in the supine position. PMID:18976269

  17. Does pointing facilitate the recall of serial positions in visuospatial working memory?

    PubMed

    Spataro, Pietro; Marques, Valeria R S; Longobardi, Emiddia; Rossi-Arnaud, Clelia

    2015-09-01

    The present study examined the question of whether pointing enhances the serial recall of visuospatial positions. Thirty-six participants were presented with 40 target arrays varying in length from five to eight items, with each position appearing sequentially in red for 1 s. The task was to reproduce the order of presentation of the positions on a blank matrix. Results showed that, for five-, six-, and seven-item arrays, order memory was significantly better in the passive view than in the pointing condition, and the serial position curves displayed both recency and priority effects. Interestingly, the advantage of the passive-view condition was more pronounced in the early than in the late positions. For eight-item arrays, no significant differences were found between the passive view and the pointing conditions. Overall, the present data provide no evidence in support of the view that pointing facilitates the recall of serial positions. PMID:26224261

  18. The Sudbury School Strike.

    ERIC Educational Resources Information Center

    Wilkinson, Derek

    1989-01-01

    Although the deleterious effects of teacher strikes on students have been proclaimed in the new media, scant research exists. This study detects no effects whatever in subsequent university performance of a cohort whose last year of high school was interrupted by a three-month strike. The strike did influence the non-college-bound student dropout…

  19. Rattlesnake strike behavior: kinematics

    PubMed

    Kardong; v

    1998-03-01

    The predatory behavior of rattlesnakes includes many distinctive preparatory phases leading to an extremely rapid strike, during which venom is injected. The rodent prey is then rapidly released, removing the snake's head from retaliation by the prey. The quick action of the venom makes possible the recovery of the dispatched prey during the ensuing poststrike period. The strike is usually completed in less than 0.5 s, placing a premium on an accurate strike that produces no significant errors in fang placement that could result in poor envenomation and subsequent loss of the prey. To clarify the basis for effective strike performance, we examined the basic kinematics of the rapid strike using high-speed film analysis. We scored numerous strike variables. Four major results were obtained. (1) Neurosensory control of the strike is based primarily upon sensory inputs via the eyes and facial pits to launch the strike, and upon tactile stimuli after contact. Correction for errors in targeting occurs not by a change in strike trajectory, but by fang repositioning after the jaws have made contact with the prey. (2) The rattlesnake strike is based upon great versatility and variation in recruitment of body segments and body postures. (3) Forces generated during acceleration of the head are transferred to posterior body sections to decelerate the head before contact with the prey, thereby reducing impact forces upon the snake's jaws. (4) Body acceleration is based on two patterns of body displacement, one in which acute sections of the body open like a gate, the other in which body segments flow around postural curves similar to movements seen during locomotion. There is one major implication of these results: recruitment of body segments, launch postures and kinematic features of the strike may be quite varied from strike to strike, but the overall predatory success of each strike by a rattlesnake is very consistent.

    PMID:9464964

  20. Constraints on arm position when pointing in three dimensions: Donders' law and the Fick gimbal strategy.

    PubMed

    Hore, J; Watts, S; Vilis, T

    1992-08-01

    1. While making saccades between targets with the head stationary, eye positions are constrained to two of the possible three degrees of freedom. Classically this constraint has been described by Donders' and Listing's laws. The objective was to determine whether these laws also apply for the straight arm when pointing between different targets. Thus we determined whether the arm adopts only one angular position for every pointing direction (Donders' law) and whether these positions can be described by rotations from a reference position about axes that lie in a plane (Listing's law). 2. The angular positions (orientations) of the arm in three-dimensional space were studied as subjects pointed with a straight arm at different targets. Arm position was measured with the search coil technique by means of coils attached to the back of the hand. Pointing was studied over a range of +/- 45 degrees in all directions from a central target located 45 degrees to the right of the straight-ahead position. 3. The positions of the arm in space were described by quaternion vectors, i.e., a particular position was described in terms of the axis and amplitude of a rotation from a reference position to that position. Using this description, it was found that the straight arm adopted a similar orientation (standard deviations ranged from 2.8 to 4.8 degrees) when pointing at a particular target irrespective of which target from which it had moved. 4. The angular position vectors for arm positions associated with relatively small movements (e.g., less than +/- 30 degrees) lay in a flat surface with minimal torsion. At first sight, this surface appeared to be similar to Listing's plane of the eye. However, for positions associated with larger movements (e.g., +/- 45 degrees) it became apparent that, unlike the eye, the surface deviated from one obeying Listing's law, i.e., it was twisted and showed torsion like that produced by rotations around the horizontal and vertical axes of a

  1. An Integer Precise Point Positioning technique for sea surface observations using a GPS buoy

    NASA Astrophysics Data System (ADS)

    Fund, F.; Perosanz, F.; Testut, L.; Loyer, S.

    2013-04-01

    GPS data dedicated to sea surface observation are usually processed using differential techniques. Unfortunately, the precision of resulting kinematic positions is baseline-length dependent. So, high precision sea surface observations using differential GPS techniques are limited to coasts, lakes, and rivers. Recent improvements in GPS satellite products (orbits, clocks, and phase biases) make phase ambiguity fixing at the zero difference level achievable and opens up the observation of the sea surface without geographical constraints. This paper recalls the concept of the Integer Precise Point Positioning technique and discusses the precision of GPS buoy positioning. A sequential version of the GINS software has been implemented to achieve single epoch GPS positioning. We used 1 Hz data from a two week GPS campaign conducted in the Kerguelen Islands. A GPS buoy has been moored close to a radar gauge and 90 m away from a permanent GPS station. This infrastructure offers the opportunity to compare both kinematic Integer Precise Point Positioning and classical differential GPS positioning techniques to in situ radar gauge data. We found that Precise Point Positioning results are not significantly biased with respect to radar gauge data and that horizontal time series are consistent with differential processing at the sub-centimetre precision level. Nevertheless, standard deviations of height time series with respect to radar gauge data are typically [4-5] cm. The dominant driver for noise at this level is attributed to errors in tropospheric estimates which propagate into position solutions.

  2. GPS-based orbit determination and point positioning under selective availability

    NASA Astrophysics Data System (ADS)

    Bar-Sever, Yoaz E.; Yunck, Thomas P.; Wu, Sien-Chong

    Selective availability (SA) degrades the positioning accuracy for nondifferential users of the GPS Standard Positioning Service (SPS). The often quoted SPS accuracy available under normal conditions is 100 m 2DRMS. In the absence of more specific information, many prospective SPS users adopt the 100 m value in their planning, which exaggerates the error in many cases. SA error is examined for point positioning and dynamic orbit determination for an orbiting user. To minimize SA error, nondifferential users have several options: expand their field of view; observe as many GPS satellites as possible; smooth the error over time; and employ precise GPS ephemerides computed independently, as by NASA and the NGS, rather than the broadcast ephemeris. Simulations show that 3D point position error can be kept to 30 m, and this can be smoothed to 3 m in a few hours.

  3. GPS-based orbit determination and point positioning under selective availability

    NASA Technical Reports Server (NTRS)

    Bar-Sever, Yoaz E.; Yunck, Thomas P.; Wu, Sien-Chong

    1990-01-01

    Selective availability (SA) degrades the positioning accuracy for nondifferential users of the GPS Standard Positioning Service (SPS). The often quoted SPS accuracy available under normal conditions is 100 m 2DRMS. In the absence of more specific information, many prospective SPS users adopt the 100 m value in their planning, which exaggerates the error in many cases. SA error is examined for point positioning and dynamic orbit determination for an orbiting user. To minimize SA error, nondifferential users have several options: expand their field of view; observe as many GPS satellites as possible; smooth the error over time; and employ precise GPS ephemerides computed independently, as by NASA and the NGS, rather than the broadcast ephemeris. Simulations show that 3D point position error can be kept to 30 m, and this can be smoothed to 3 m in a few hours.

  4. On the Choice of Access Point Selection Criterion and Other Position Estimation Characteristics for WLAN-Based Indoor Positioning.

    PubMed

    Laitinen, Elina; Lohan, Elena Simona

    2016-01-01

    The positioning based on Wireless Local Area Networks (WLAN) is one of the most promising technologies for indoor location-based services, generally using the information carried by Received Signal Strengths (RSS). One challenge, however, is the huge amount of data in the radiomap database due to the enormous number of hearable Access Points (AP) that could make the positioning system very complex. This paper concentrates on WLAN-based indoor location by comparing fingerprinting, path loss and weighted centroid based positioning approaches in terms of complexity and performance and studying the effects of grid size and AP reduction with several choices for appropriate selection criterion. All results are based on real field measurements in three multi-floor buildings. We validate our earlier findings concerning several different AP selection criteria and conclude that the best results are obtained with a maximum RSS-based criterion, which also proved to be the most consistent among the different investigated approaches. We show that the weighted centroid based low-complexity method is very sensitive to AP reduction, while the path loss-based method is also very robust to high percentage removals. Indeed, for fingerprinting, 50% of the APs can be removed safely with a properly chosen removal criterion without increasing the positioning error much. PMID:27213395

  5. On the Choice of Access Point Selection Criterion and Other Position Estimation Characteristics for WLAN-Based Indoor Positioning

    PubMed Central

    Laitinen, Elina; Lohan, Elena Simona

    2016-01-01

    The positioning based on Wireless Local Area Networks (WLAN) is one of the most promising technologies for indoor location-based services, generally using the information carried by Received Signal Strengths (RSS). One challenge, however, is the huge amount of data in the radiomap database due to the enormous number of hearable Access Points (AP) that could make the positioning system very complex. This paper concentrates on WLAN-based indoor location by comparing fingerprinting, path loss and weighted centroid based positioning approaches in terms of complexity and performance and studying the effects of grid size and AP reduction with several choices for appropriate selection criterion. All results are based on real field measurements in three multi-floor buildings. We validate our earlier findings concerning several different AP selection criteria and conclude that the best results are obtained with a maximum RSS-based criterion, which also proved to be the most consistent among the different investigated approaches. We show that the weighted centroid based low-complexity method is very sensitive to AP reduction, while the path loss-based method is also very robust to high percentage removals. Indeed, for fingerprinting, 50% of the APs can be removed safely with a properly chosen removal criterion without increasing the positioning error much. PMID:27213395

  6. Strike Manual: Related to Potential School Employee Strike Action.

    ERIC Educational Resources Information Center

    Paterson, Lee T., Ed.

    This manual is designed to help school boards and administrators avoid strikes, survive them, and recover from them when they are over. Chapter 1 distinguishes between public and private sector strikes; defines different kinds of strike strategies, negotiation goals, and strike goals; and provides a strike evaluation checklist for the employee…

  7. Some aspects of improving Multi-GNSS real-time precise point positioning services

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Ge, Maorong; Li, Xingxing; Schuh, Harald

    2016-04-01

    Multi-GNSS is expected to achieve a real-time precise point positioning service with better accuracy and reliability than GPS-only service. In this contribution, we address several critical challenges in implementing a GPS+GLONASS+BeiDou+Galileo service to provide global users with centimeter-level positioning in real-time based on the software system developed at GFZ. The specific issues of improving GLONASS orbit quality by resolving ambiguity over long baselines, estimation of inter-system/frequency biases, ambiguity resolution in real-time clock estimation and positioning, and computation efficiency are discussed and investigated in detail. Experimental validation is carried out based on the data streams of the IGS/MGEX network. The real-time orbit and clock products are assessed by comparison with the IGS/MGEX final products, and orbits are also assessed by overlapping day boundaries and satellite laser ranging. The phase bias (uncalibrated phase delay) products are evaluated by comparison with the post-processing results. It is demonstrated that multi-GNSS can contribute significantly to improving the global real-time precise point positioning service in terms of convergence time and accuracy. Keywords: Multi-GNSS, Real-Time, Precise Orbit Determination, Precise Point Positioning, Ambiguity Resolution, Inter-System/Frequency Bias, Algorithm Efficiency

  8. Patterns of variation in feeding strike kinematics of juvenile ghost praying mantis (Phyllocrania paradoxa): are components of the strike stereotypic?

    PubMed

    Oufiero, Christopher E; Nguyen, Tammy; Sragner, Annie; Ellis, Angelah

    2016-09-01

    Functional systems, such as feeding mechanics, often involve the evolution of several components of the musculoskeletal system that are moved in coordination to capture prey. Because these systems often involve the quick movement of several structures, some feeding systems have been hypothesized to be stereotypic. While the motor activity patterns are often stereotyped, the subsequent kinematics can be variable, many times in response to variation in prey stimulus (e.g. prey position). Patterns of feeding kinematics have been well studied among vertebrates, with less attention on invertebrate systems. The goal of this study was to examine the amount of stereotypy in the feeding strike kinematics of praying mantises. We filmed eight juvenile ghost praying mantises (Phyllocrania paradoxa) at 1000 Hz across several days within instar 7. We digitized several points that represent the movement of the coxa, trochanter-femur and tibia of the raptorial foreleg to obtain a set of kinematics including angles and angular velocities of the joint, as well as body lunge. Using the coefficient of variation, we found less stereotypy in the approach stage of the strike compared with the sweep. Using Bonferroni-corrected Pearson's correlations of kinematics with prey position, we found few traits related to prey position with the exception of some kinematics of the coxa joint and the amount of lunge used during the strike. Our results suggest that several components of the praying mantis strike are stereotypic, while others exhibit flexibility to ensure successful capture of the prey. PMID:27358472

  9. X-point position dependence of edge intrinsic toroidal rotation on the Tokamak à Configuration Variable

    SciTech Connect

    Stoltzfus-Dueck, T.; Karpushov, A. N.; Sauter, O.; Duval, B. P.; Labit, B.; Reimerdes, H.; Vijvers, W. A. J.; Camenen, Y.

    2015-05-15

    Recent theoretical work predicts intrinsic toroidal rotation in the tokamak edge to depend strongly on the normalized major radial position of the X-point. With this motivation, we conducted a series of Ohmic L-mode shots on the Tokamak à Configuration Variable, moving the X-point from the inboard to the outboard edge of the last closed flux surface in both lower and upper single null configurations. The edge toroidal rotation evolved from strongly co-current for an inboard X-point to either vanishing or counter-current for an outboard X-point, in agreement with the theoretical expectations. The whole rotation profile shifted roughly rigidly with the edge rotation, resulting in variation of the peak core rotation by more than a factor of two. Core rotation reversals had little effect on the edge rotation. Edge rotation was slightly more counter-current for unfavorable than favorable ∇B drift discharges.

  10. X-point position dependence of edge intrinsic toroidal rotation on the Tokamak à Configuration Variablea)

    NASA Astrophysics Data System (ADS)

    Stoltzfus-Dueck, T.; Karpushov, A. N.; Sauter, O.; Duval, B. P.; Labit, B.; Reimerdes, H.; Vijvers, W. A. J.; Camenen, Y.

    2015-05-01

    Recent theoretical work predicts intrinsic toroidal rotation in the tokamak edge to depend strongly on the normalized major radial position of the X-point. With this motivation, we conducted a series of Ohmic L-mode shots on the Tokamak à Configuration Variable, moving the X-point from the inboard to the outboard edge of the last closed flux surface in both lower and upper single null configurations. The edge toroidal rotation evolved from strongly co-current for an inboard X-point to either vanishing or counter-current for an outboard X-point, in agreement with the theoretical expectations. The whole rotation profile shifted roughly rigidly with the edge rotation, resulting in variation of the peak core rotation by more than a factor of two. Core rotation reversals had little effect on the edge rotation. Edge rotation was slightly more counter-current for unfavorable than favorable ∇B drift discharges.

  11. Strikingly high false positivity of surveillance FDG-PET/CT scanning among patients with diffuse large cell lymphoma in the rituximab era.

    PubMed

    Avivi, Irit; Zilberlicht, Ariel; Dann, Eldad J; Leiba, Ronit; Faibish, Tal; Rowe, Jacob M; Bar-Shalom, Rachel

    2013-05-01

    Predictive value (PV) of surveillance fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with diffuse large B-cell lymphoma (DLBCL) treated with chemotherapy-rituximab (R) versus chemotherapy only, remains unclear. The aim of the current study was to compare the performance of surveillance PET in DLBCL patients receiving CHOP (cyclophosphamide, hydroxydaunorubicin hydrochloride, vincristine, and prednisone) alone versus CHOP-R. Institutional database was retrospectively searched for adults with newly diagnosed DLBCL, receiving CHOP or CHOP-R, who achieved complete remission and underwent surveillance PETs. Follow-up (FU) PET was considered positive for recurrence in case of an uptake unrelated to physiological or known benign process. Results were confirmed by biopsy, imaging and clinical FU. One hundred nineteen patients, 35 receiving CHOP and 84 CHOP-R, who underwent 422 FU-PETs, were analyzed. At a median PET-FU of 3.4 years, 31 patients relapsed (17 vs. 14, respectively; P = 0.02). PET detected all relapses, with no false-negative studies. Specificity and positive PV (PPV) were significantly lower for patients receiving CHOP-R vs. CHOP (84% vs. 87%, P = 0.023; 23% vs. 74%, P < 0.0001), reflecting a higher false-positive (FP) rate in subjects receiving CHOP-R (77% vs. 26%, P < 0.001). In the latter group, FP-rate remained persistently high up to 3 years post-therapy. Multivariate analysis confirmed rituximab to be the most significant predictor for FP-PET. In conclusion, routine surveillance FDG-PET is not recommended in DLBCL treated with rituximab; strict criteria identifying patients in whom FU-PET is beneficial are required. PMID:23423884

  12. Development of Electronics for the ATF2 Interaction Point Region Beam Position Monitor

    SciTech Connect

    Kim, Youngim; Heo, Ae-young; Kim, Eun-San; Boogert, Stewart; Honda, Yosuke; Tauchi, Toshiaki; Terunuma, Nobuhiro; May, Justin; McCormick, Douglas; Smith, Tonee; /SLAC

    2012-08-14

    Nanometer resolution beam position monitors have been developed to measure and control beam position stability at the interaction point region of ATF2. The position of the beam has to be measured to within a few nanometers at the interaction point. In order to achieve this performance, electronics for the low-Q IP-BPM was developed. Every component of the electronics have been simulated and checked on the bench and using the ATF2 beam. We will explain each component and define their working range. Then, we will show the performance of the electronics measured with beam signal. ATF2 is a final focus test beam line for ILC in the framework of the ATF international collaboration. The new beam line was constructed to extend the extraction line at ATF, KEK, Japan. The first goal of ATF2 is the acheiving of a 37 nm vertical beam size at focal point (IP). The second goal is to stabilize the beam at the focal point at a few nanometer level for a long period in order to ensure the high luminosity. To achieve these goals a high resolution IP-BPM is essential. In addition for feedback applications a low-Q system is desirable.

  13. Should doctors strike?

    PubMed

    Park, John J; Murray, Scott A

    2014-05-01

    Last year in June, British doctors went on strike for the first time since 1975. Amidst a global economic downturn and with many health systems struggling with reduced finances, around the world the issue of public health workers going on strike is a very real one. Almost all doctors will agree that we should always follow the law, but often the law is unclear or does not cover a particular case. Here we must appeal to ethical discussion. The General Medical Council, in its key guidance document for practising doctors, Good Medical Practice, claims that 'Good doctors make the care of their patients their first concern'. Is this true? And if so, how is this relevant to the issue of striking? One year on since the events, we carefully reflect and argue whether it was right for doctors to pursue strike action, and call for greater discussion of ethical issues such as the recent strikes, particularly among younger members of the profession. PMID:23788560

  14. A device to improve the SNR of the measurement of the positional floating reference point

    NASA Astrophysics Data System (ADS)

    Jiang, Jingying; Rong, Xuzheng; Zhang, Hao; Xu, Kexin

    2013-02-01

    Previous studies have preliminarily validated the floating reference method and shown that it has the potential to improve the accuracy of non-invasive blood glucose sensing by Near-Infrared Spectroscopy. In order to make this method practical, it is necessary to precisely verify and measure the existence and variation features of the positional floating reference point. In this talk, a device which can precisely verify and measure the positional floating reference point is built. Since the light intensity of diffuse reflectance from the tested sample is very weak, a multipath detecting fibers system was built to improve signal-to-noise ratio. In this system, the fibers encircle the light source fiber which is regarded as the reference center of detecting fibers while they are moving. In addition, the position of each fiber is accurately controlled by manual translation stage to keep all detecting fibers always in the same radius around light source fiber. This ensures that received signal is coming from the same radial distance of light source. The variation of signal-to-noise ratio along with the different radial distance was investigated based on experiments. Results show that the application of this device could improve signal-to-noise ratio, and provide a new experimental method for the further study of positional floating reference point.

  15. Research on acupuncture points and cortical functional activation position in cats by infrared imaging detection

    NASA Astrophysics Data System (ADS)

    Chen, Shuwang; Sha, Zhanyou; Wang, Shuhai; Wen, Huanming

    2007-12-01

    The research of the brain cognition is mainly to find out the activation position in brain according to the stimulation at present in the world. The research regards the animals as the experimental objects and explores the stimulation response on the cerebral cortex of acupuncture. It provides a new method, which can detect the activation position on the creatural cerebral cortex directly by middle-far infrared imaging. According to the theory of local temperature situation, the difference of cortical temperature maybe associate with the excitement of cortical nerve cells, the metabolism of local tissue and the local hemal circulation. Direct naked detection of temperature variety on cerebral cortex is applied by middle and far infrared imaging technology. So the activation position is ascertained. The effect of stimulation response is superior to other indirect methods. After removing the skulls on the head, full of cerebral cortex of a cat are exposed. By observing the infrared images and measuring the temperatures of the visual cerebral cortex during the process of acupuncturing, the points are used to judge the activation position. The variety in the cortical functional sections is corresponding to the result of the acupuncture points in terms of infrared images and temperatures. According to experimental results, we know that the variety of a cortical functional section is corresponding to a special acupuncture point exactly.

  16. X-Point-Position-Dependent Intrinsic Toroidal Rotation in the Edge of the TCV Tokamak.

    PubMed

    Stoltzfus-Dueck, T; Karpushov, A N; Sauter, O; Duval, B P; Labit, B; Reimerdes, H; Vijvers, W A J; Camenen, Y

    2015-06-19

    Edge intrinsic rotation was investigated in Ohmic L-mode discharges on the Tokamak à Configuration Variable, scanning the major radial position of the X point, R(X). Edge rotation decreased linearly with increasing R(X), vanishing or becoming countercurrent for an outboard X point, in agreement with theoretical expectations. The core rotation profile shifted fairly rigidly with the edge rotation, changing the central rotation speed by more than a factor of two. Core rotation reversals had little effect on the edge rotation velocity. Edge rotation was modestly more countercurrent in unfavorable than favorable ∇B shots. PMID:26196980

  17. Analytical expressions for position error in triangulation solution of point in space for several station configurations

    NASA Technical Reports Server (NTRS)

    Long, S. A. T.

    1974-01-01

    Analytical expressions are derived to first order for the rms position error in the triangulation solution of a point object in space for several ideal observation-station configurations. These expressions provide insights into the nature of the dependence of the rms position error on certain of the experimental parameters involved. The station geometries examined are: (1) the configuration of two arbitrarily located stations; (2) the symmetrical circular configuration of two or more stations with equal elevation angles; and (3) the circular configuration of more than two stations with equal elevation angles, when one of the stations is permitted to drift around the circle from its position of symmetry. The expressions for the rms position error are expressed as functions of the rms line-of-sight errors, the total number of stations of interest, and the elevation angles.

  18. Driver's eye position relative to the 'H' point for trucks and buses.

    PubMed

    Ruffell Smith, H P

    1973-09-01

    The eye position of subjects has been measured while they were driving the prototype of a bus intended for public service and in a static mock-up of this prototype. The average eye position observed in these tests was confirmed by photographing professional drivers while they drove an existing public service bus. With seat backs inclined at 10 degrees , the average eye position was found to be between 10 and 11 cms (4 and 4.5 in) in advance of the hip hinge point. The eye position found in this way agrees with an SAE recommendation but differs in its fore and aft dimension relative to the hip joint from that specified in some national and international regulations. PMID:15677123

  19. Effect of the 24 September 2011 solar radio burst on precise point positioning service

    NASA Astrophysics Data System (ADS)

    Sreeja, V.; Aquino, M.; Jong, Kees; Visser, Hans

    2014-03-01

    An intense solar radio burst occurred on 24 September 2011, which affected the tracking of Global Navigation Satellite Systems' (GNSS) signals by receivers located in the sunlit hemisphere of the Earth. This manuscript presents for the first time the impacts of this radio burst on the availability of Fugro's real-time precise point positioning service for GNSS receivers and on the quality of the L band data link used to broadcast this service. During the peak of the radio burst (12:50-13:20 UT), a reduction in the L band signal-to-noise ratio (SNR) is observed. For some receiver locations, a reset in the position filter is observed, which can be either due to the reduction in the L band SNR or the reduction in the number of tracked GNSS satellites. This reset in the position filter is accompanied by degradation in the positioning accuracy, which is also discussed herein.

  20. Stochastic Modeling Considering Ionospheric Scintillation Effects on GNSS Relative and Point Positioning

    NASA Astrophysics Data System (ADS)

    Silva, H. A.; Camargo, P. D.; Monico, J. F.; Aquino, M.; Marques, H. A.; de Franceschi, G.

    2008-12-01

    Nowadays, Global Navigation Satellite Systems (GNSS), especially the Global Positioning System (GPS), represent one of the most used techniques for geodetic positioning. The functional models related with the GNSS observables are better understood than the stochastic models, considering that the development of the latter is more complex. Usually, the stochastic models are used in a simplified form, as the standard models, which assume that all the GNSS observables are statistically independent and have the same variance. However, the stochastic models may be investigated in more detail, considering for example, the effects of ionospheric scintillation. The high latitudes regions experiment strong influence of the ionospheric effects, in particular ionospheric scintillation. Considering the availability of specially designed GNSS receivers that provide ionospheric scintillation parameters, these effects can be mitigated through improved stochastic models. This paper presents the methodology and results from GPS relative and point positioning considering ionospheric scintillation in the stochastic modeling. Two programs have been developed to obtain the results from relative and point positioning: "GPSeq" (currently under development at the FCT/UNESP Sao Paulo State University - Brazil) and "pp_sc" (developed in a collaborative project between FCT/UNESP and Nottingham University - UK). The point positioning approach can be realized considering an epoch by epoch solution and the relative positioning using a Kalman Filter and the LAMBDA method to solve the Double Differences ambiguities. Both programs have the option to estimate the ionospheric residuals as one stochastic process using the white noise or random walk correlation models. In both cases it is also possible to use the L1/L2 ion-free linear combination. The stochastic modeling considering ionospheric scintillation has been implemented based in the models of Conker et al. (2003), following the approach

  1. Position Estimation of Access Points in 802.11 Wireless Networks

    SciTech Connect

    Kent, C A; Dowla, F U; Atwal, P K; Lennon, W J

    2003-12-05

    We developed a technique to locate wireless network nodes using multiple time-of-flight range measurements in a position estimate. When used with communication methods that allow propagation through walls, such as Ultra-Wideband and 802.11, we can locate network nodes in buildings and in caves where GPS is unavailable. This paper details the implementation on an 802.11a network where we demonstrated the ability to locate a network access point to within 20 feet.

  2. Tunable band gap near the Dirac point in nonlinear negative-zero-positive index metamaterial waveguide

    SciTech Connect

    Shen Ming; Ruan Linxu; Shi Jielong; Wang Qi; Wang Xinglin

    2011-04-15

    We make theoretical investigations of the nonlinear guided modes near the Dirac point (DP) in nonlinear negative-zero-positive index metamaterial (NZPIM) waveguide. When the nonlinearity is self-focusing, an asymmetric forbidden band exists near the DP that can be modulated by the strength of the nonlinearity. However, the self-defocusing nonlinearity can completely eliminate the asymmetric band gap. We also study the nonlinear surface waves in such nonlinear NZPIM waveguide. These results may predict analogous phenomena in nonlinear graphene.

  3. Bowl breakout: Escaping the positive region when searching for saddle points

    SciTech Connect

    Pedersen, Andreas; Luiser, Mathieu

    2014-07-14

    We present a scheme improving the minimum-mode following method for finding first order saddle points by confining the displacements of atoms to the subset of those subject to the largest force. By doing so it is ensured that the displacement remains of a local character within regions where all eigenvalues of the Hessian matrix are positive. However, as soon as a region is entered where an eigenvalue turns negative all atoms are released to maintain the ability of determining concerted moves. Applying the proposed scheme reduces the required number of force calls for the determination of connected saddle points by a factor two or more compared to a free search. Furthermore, a wider distribution of the relevant low barrier saddle points is obtained. Finally, the dependency on the initial distortion and the applied maximal step size is reduced making minimum-mode guided searches both more robust and applicable.

  4. [Variations in the position and point of origin of the vermiform appendix].

    PubMed

    Delić, Jasmin; Savković, Admedina; Isaković, Eldar

    2002-01-01

    There were investigated variations of appendix vermiformis in the place of origin and position. The investigations were carried out on 50 human preparations of adults of both sexes, unintentional choice. The position and relation between intestinum caecum and appendix vermiformis were determined by forensic medical and pathoanatomical autopsy. Place of origin of appendix vermiformis, from wall of intestinum caecum is determined by anatomical dissection. Intestinum caecum has a variable shape and it occurs in two forms: conical, which dominates (56%) and square (44%). It has constant position in fossa iliaca dextra in 100% of 50 investigated cases. Appendix vermiformis is fully variable organ as for position and the place of origin from the wall of intestinum caecum. Dominantly (52%) it has rising position, and two subtypes are present: retrocecal (more expressed-38%) related to the retrocolic subtype (14%). Very frequent position of appendix vermiformis is a falling one (32%), in which pelvic position is more frequent (26%) related to descendent position (6%). Appendix vermifirmis is located subcaecaly in 8% of total number of investigated cases, found in three subtypes. It is found out that ostium appendicis vermiformis has a variable position in the wall of intestinum caecum. It is predominantly placed in the middle of the lower pole of the intestinum caecum (58%), in medial wall it is present in 32%, of all investigated, and in the lateral wall in the least number case 10%. The results of these investigations point out how important is to know variable anatomies of appendix vermiformis, for the clinical image of acute appendicitis is undoubtedly caused by the variable anatomical relations. PMID:11917693

  5. Flight Evaluation of GPS Precise Point Positioning Software for Helicopter Navigation

    NASA Astrophysics Data System (ADS)

    Shimizu, Yutaka; Murata, Masaaki

    In 2007 development and assessment of a precise point positioning (PPP) software for land vehicular navigation have been reported. This paper presents one phase of the continued study at NDA for further extension of the software to helicopter navigation. For 3D users, the height-dependent tropospheric delay is a critical factor, and so the sophisticated correction models and parameter estimation strategies have to be investigated to mitigate the delay effect. Since the precise positioning results become available only after the filter convergence and the filter generally converges rather slowly, speeding up the convergence has to be taken into special attention. In this paper we propose some new ideas to cope with this problem, and report the test using GPS helicopter flight data in post-processing. With proposed techniques including the variable Q and pseudo-observation concept, we show that point positioning accuracy at about decimeter level both horizontally and vertically can be achieved with improved convergence within about half an hour. We also show that the use of the high-rate (30-second) satellite clocks rather than the 5-minute clocks further improves positioning accuracy at sub-decimeter level in each 3D coordinate.

  6. Real-Time IGS products verification in the context of their use in Precise Point Positioning

    NASA Astrophysics Data System (ADS)

    Hadas, Tomasz; Bosy, Jaroslaw; Kaplon, Jan; Sierny, Jan

    2013-04-01

    Precise Point Positioning (PPP) is a positioning technique of single GNSS receiver which applies high quality products from permanent GNSS observations to utilize the computational potential of global network analysis. Estimated satellite orbits and clocks corrections are introduced into equation system as known parameters. PPP requires the application of precise products, since their quality directly reflects the positioning accuracy. In June 2007 IGS Real-time Pilot Project has started in order to satisfy real-time users, which is especially important for Precise Point Positioning. Currently available streams including precise orbits, clocks and code biases are standardized on RTCM-SC 104 formats and may be used as a substitute for ultra-rapid products. The target combination product performances are 0.3ns for satellite clock accuracy and orbit accuracy at the level of the IGS Ultra predictions with maximum latency of 10s. This study presents the quality assessment of currently available Real-Time IGS products. Long-term test include comparisons of disseminated information with final and high-rate products, stability assessment over time, as well as latency validation of available RTCM streams.

  7. Accelerating the Convergence Speed of Precise Point Positioning by Using Multi-mode GNSS

    NASA Astrophysics Data System (ADS)

    Chao, Song; Jin-ming, Hao

    2016-04-01

    The Precise Point Positioning (PPP) does not need the support of base stations, and it has broad application prospects. However, the convergence time of PPP is long. In order to accelerate the convergence speed of PPP, the PPP model using multi-mode GNSS (Global Navigation Satellite System) is discussed. The experiments show that the convergence speed becomes faster by using the multi-mode GNSS, the mean percentage of time reduction for converging to different precisions (10 cm, 15 cm, and 20 cm) is 42%, 78%, and 74%, respectively; meanwhile, in the severe regions, such as in the mountainous regions, the number of observable satellites becomes fewer, and the PPP sometimes cannot achieve positioning using a simple system. But the PPP using multi-mode GNSS can achieve positioning and accelerate the convergence.

  8. Accelerating the Convergence Speed of Precise Point Positioning by Using Multi-GNSS

    NASA Astrophysics Data System (ADS)

    Song, C.; Hao, J. M.

    2015-07-01

    The Precise Point Positioning (PPP) does not need the support of base station, and it has broad application prospects. However, the convergence time of PPP is long. In order to accelerate the convergence speed of PPP, the PPP model using multi-GNSS (Global Navigation Satellite System) is discussed. The experiments show that the convergence speed becomes faster by using the multi-GNSS, the mean percentage of time reduction for converging to different precisions (10 cm, 15 cm, and 20 cm) is 42%, 78%, and 74%, respectively; meanwhile, in the severe regions, such as in the mountainous regions, the number of observed satellites becomes fewer, and the PPP sometimes cannot achieve positioning using single system. But PPP using multi-GNSS can achieve positioning and accelerate the convergence.

  9. Precise Point Positioning for the Efficient and Robust Analysis of GPS Data from Large Networks

    NASA Technical Reports Server (NTRS)

    Zumberge, J. F.; Heflin, M. B.; Jefferson, D. C.; Watkins, M. M.; Webb, F. H.

    1997-01-01

    Networks of dozens to hundreds of permanently operating precision Global Positioning System (GPS) receivers are emerging at spatial scales that range from 10(exp 0) to 10(exp 3) km. To keep the computational burden associated with the analysis of such data economically feasible, one approach is to first determine precise GPS satellite positions and clock corrections from a globally distributed network of GPS receivers. Their, data from the local network are analyzed by estimating receiver- specific parameters with receiver-specific data satellite parameters are held fixed at their values determined in the global solution. This "precise point positioning" allows analysis of data from hundreds to thousands of sites every (lay with 40-Mflop computers, with results comparable in quality to the simultaneous analysis of all data. The reference frames for the global and network solutions can be free of distortion imposed by erroneous fiducial constraints on any sites.

  10. Precise Point Positioning for the Efficient and Robust Analysis of GPS Data From Large Networks

    NASA Technical Reports Server (NTRS)

    Zumberge, J. F.; Heflin, M. B.; Jefferson, D. C.; Watkins, M. M.; Webb, F. H.

    1997-01-01

    Networks of dozens to hundreds of permanently operating precision Global Positioning System (GPS) receivers are emerging at spatial scales that range from 10(exp 0) to 10(exp 3) km. To keep the computational burden associated with the analysis of such data economically feasible, one approach is to first determine precise GPS satellite positions and clock corrections from a globally distributed network of GPS receivers. Then, data from the local network are analyzed by estimating receiver specific parameters with receiver-specific data; satellite parameters are held fixed at their values determined in the global solution. This "precise point positioning" allows analysis of data from hundreds to thousands of sites every day with 40 Mflop computers, with results comparable in quality to the simultaneous analysis of all data. The reference frames for the global and network solutions can be free of distortion imposed by erroneous fiducial constraints on any sites.

  11. Estimated results analysis and application of the precise point positioning based high-accuracy ionosphere delay

    NASA Astrophysics Data System (ADS)

    Wang, Shi-tai; Peng, Jun-huan

    2015-12-01

    The characterization of ionosphere delay estimated with precise point positioning is analyzed in this paper. The estimation, interpolation and application of the ionosphere delay are studied based on the processing of 24-h data from 5 observation stations. The results show that the estimated ionosphere delay is affected by the hardware delay bias from receiver so that there is a difference between the estimated and interpolated results. The results also show that the RMSs (root mean squares) are bigger, while the STDs (standard deviations) are better than 0.11 m. When the satellite difference is used, the hardware delay bias can be canceled. The interpolated satellite-differenced ionosphere delay is better than 0.11 m. Although there is a difference between the between the estimated and interpolated ionosphere delay results it cannot affect its application in single-frequency positioning and the positioning accuracy can reach cm level.

  12. A method of undifferenced ambiguity resolution for GPS+GLONASS precise point positioning

    NASA Astrophysics Data System (ADS)

    Yi, Wenting; Song, Weiwei; Lou, Yidong; Shi, Chuang; Yao, Yibin

    2016-05-01

    Integer ambiguity resolution is critical for achieving positions of high precision and for shortening the convergence time of precise point positioning (PPP). However, GLONASS adopts the signal processing technology of frequency division multiple access and results in inter-frequency code biases (IFCBs), which are currently difficult to correct. This bias makes the methods proposed for GPS ambiguity fixing unsuitable for GLONASS. To realize undifferenced GLONASS ambiguity fixing, we propose an undifferenced ambiguity resolution method for GPS+GLONASS PPP, which considers the IFCBs estimation. The experimental result demonstrates that the success rate of GLONASS ambiguity fixing can reach 75% through the proposed method. Compared with the ambiguity float solutions, the positioning accuracies of ambiguity-fixed solutions of GLONASS-only PPP are increased by 12.2%, 20.9%, and 10.3%, and that of the GPS+GLONASS PPP by 13.0%, 35.2%, and 14.1% in the North, East and Up directions, respectively.

  13. Precise Point Positioning technique for short and long baselines time transfer

    NASA Astrophysics Data System (ADS)

    Lejba, Pawel; Nawrocki, Jerzy; Lemanski, Dariusz; Foks-Ryznar, Anna; Nogas, Pawel; Dunst, Piotr

    2013-04-01

    In this work the clock parameters determination of several timing receivers TTS-4 (AOS), ASHTECH Z-XII3T (OP, ORB, PTB, USNO) and SEPTENTRIO POLARX4TR (ORB, since February 11, 2012) by use of the Precise Point Positioning (PPP) technique were presented. The clock parameters were determined for several time links based on the data delivered by time and frequency laboratories mentioned above. The computations cover the period from January 1 to December 31, 2012 and were performed in two modes with 7-day and one-month solution for all links. All RINEX data files which include phase and code GPS data were recorded in 30-second intervals. All calculations were performed by means of Natural Resource Canada's GPS Precise Point Positioning (GPS-PPP) software based on high-quality precise satellite coordinates and satellite clock delivered by IGS as the final products. The used independent PPP technique is a very powerful and simple method which allows for better control of antenna positions in AOS and a verification of other time transfer techniques like GPS CV, GLONASS CV and TWSTFT. The PPP technique is also a very good alternative for calibration of a glass fiber link PL-AOS realized at present by AOS. Currently PPP technique is one of the main time transfer methods used at AOS what considerably improve and strengthen the quality of the Polish time scales UTC(AOS), UTC(PL), and TA(PL). KEY-WORDS: Precise Point Positioning, time transfer, IGS products, GNSS, time scales.

  14. Real-Time Single Frequency Precise Point Positioning Using SBAS Corrections.

    PubMed

    Li, Liang; Jia, Chun; Zhao, Lin; Cheng, Jianhua; Liu, Jianxu; Ding, Jicheng

    2016-01-01

    Real-time single frequency precise point positioning (PPP) is a promising technique for high-precision navigation with sub-meter or even centimeter-level accuracy because of its convenience and low cost. The navigation performance of single frequency PPP heavily depends on the real-time availability and quality of correction products for satellite orbits and satellite clocks. Satellite-based augmentation system (SBAS) provides the correction products in real-time, but they are intended to be used for wide area differential positioning at 1 meter level precision. By imposing the constraints for ionosphere error, we have developed a real-time single frequency PPP method by sufficiently utilizing SBAS correction products. The proposed PPP method are tested with static and kinematic data, respectively. The static experimental results show that the position accuracy of the proposed PPP method can reach decimeter level, and achieve an improvement of at least 30% when compared with the traditional SBAS method. The positioning convergence of the proposed PPP method can be achieved in 636 epochs at most in static mode. In the kinematic experiment, the position accuracy of the proposed PPP method can be improved by at least 20 cm relative to the SBAS method. Furthermore, it has revealed that the proposed PPP method can achieve decimeter level convergence within 500 s in the kinematic mode. PMID:27517930

  15. Precise Point Positioning with the BeiDou Navigation Satellite System

    PubMed Central

    Li, Min; Qu, Lizhong; Zhao, Qile; Guo, Jing; Su, Xing; Li, Xiaotao

    2014-01-01

    By the end of 2012, China had launched 16 BeiDou-2 navigation satellites that include six GEOs, five IGSOs and five MEOs. This has provided initial navigation and precise pointing services ability in the Asia-Pacific regions. In order to assess the navigation and positioning performance of the BeiDou-2 system, Wuhan University has built up a network of BeiDou Experimental Tracking Stations (BETS) around the World. The Position and Navigation Data Analyst (PANDA) software was modified to determine the orbits of BeiDou satellites and provide precise orbit and satellite clock bias products from the BeiDou satellite system for user applications. This article uses the BeiDou/GPS observations of the BeiDou Experimental Tracking Stations to realize the BeiDou and BeiDou/GPS static and kinematic precise point positioning (PPP). The result indicates that the precision of BeiDou static and kinematic PPP reaches centimeter level. The precision of BeiDou/GPS kinematic PPP solutions is improved significantly compared to that of BeiDou-only or GPS-only kinematic PPP solutions. The PPP convergence time also decreases with the use of combined BeiDou/GPS systems. PMID:24406856

  16. Hunger strike for science

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    Lamenting the degenerating working conditions for scientists in Russia, geophysicist Vladimir Strakhov and physicist Igor Naumenko-Bondarenko of the United Institute of Physics of the Earth (UIPE) at the Russian Academy of Sciences (RAS) have begun a hunger strike. Strakhov is General Director of UIPE, and Naumenko-Bondarenko is chairman of the Trade Union Committee of UIPE.In a press statement released on September 30 in Moscow, the geophysicists stated that they are striking to “protest the policy of the Government of the Russian Federation with regard to Russian science in general and to the Russian Academy of Sciences in particular.” They blame governmental neglect and, specifically, “the non-payment of funds that were in the 1996 budget” for the “virtual collapse of Russian science.”

  17. Datum maintenance of the main Egyptian geodetic control networks by utilizing Precise Point Positioning "PPP" technique

    NASA Astrophysics Data System (ADS)

    Rabah, Mostafa; Elmewafey, Mahmoud; Farahan, Magda H.

    2016-06-01

    A geodetic control network is the wire-frame or the skeleton on which continuous and consistent mapping, Geographic Information Systems (GIS), and surveys are based. Traditionally, geodetic control points are established as permanent physical monuments placed in the ground and precisely marked, located, and documented. With the development of satellite surveying methods and their availability and high degree of accuracy, a geodetic control network could be established by using GNSS and referred to an international terrestrial reference frame used as a three-dimensional geocentric reference system for a country. Based on this concept, in 1992, the Egypt Survey Authority (ESA) established two networks, namely High Accuracy Reference Network (HARN) and the National Agricultural Cadastral Network (NACN). To transfer the International Terrestrial Reference Frame to the HARN, the HARN was connected with four IGS stations. The processing results were 1:10,000,000 (Order A) for HARN and 1:1,000,000 (Order B) for NACN relative network accuracy standard between stations defined in ITRF1994 Epoch1996. Since 1996, ESA did not perform any updating or maintaining works for these networks. To see how non-performing maintenance degrading the values of the HARN and NACN, the available HARN and NACN stations in the Nile Delta were observed. The Processing of the tested part was done by CSRS-PPP Service based on utilizing Precise Point Positioning "PPP" and Trimble Business Center "TBC". The study shows the feasibility of Precise Point Positioning in updating the absolute positioning of the HARN network and its role in updating the reference frame (ITRF). The study also confirmed the necessity of the absent role of datum maintenance of Egypt networks.

  18. Precise point positioning with quad-constellations: GPS, BeiDou, GLONASS and Galileo

    NASA Astrophysics Data System (ADS)

    Cai, Changsheng; Gao, Yang; Pan, Lin; Zhu, Jianjun

    2015-07-01

    Multi-constellation GNSS precise point positioning (PPP) first became feasible back to 2007 but with only two constellations, namely GPS and GLONASS. With the availability of more satellites and precise orbit and clock products from BeiDou and Galileo, it is possible now to investigate PPP with four constellations, namely GPS, BeiDou, GLONASS and Galileo. This research aims at investigating the quad-constellation PPP for position determination and analyzing its positioning performance. A quad-constellation PPP model is developed to simultaneously process the observations from all the four GNSS systems. The developed model is also applicable to the PPP processing with observations from single, dual or triple constellations. The analysis on PPP accuracy and convergence time is conducted based on data processing results from both static and kinematic tests of single-constellation and multi-constellations. The three-hour static positioning results indicate that the BeiDou-only PPP accuracy is worse than the GPS-only PPP. The RMSs of position errors for BeiDou-only PPP are 5.2 cm, 2.7 cm and 8.3 cm in east, north and up directions while the ones for GPS-only PPP are 3.9 cm, 1.6 cm and 5.7 cm. The GPS/BeiDou PPP improves the positioning accuracy by 28%, 6% and 7% and reduces the convergence time by 26%, 13% and 14% over the GPS-only PPP in three coordinate components, respectively. The GPS/GLONASS PPP achieves slightly better performance than the GPS/BeiDou PPP. The triple-constellation PPP further increases the positioning accuracy and decreases the convergence time over the dual-constellation PPP. The improvement of positioning performance is not significant after adding Galileo due to currently limited number of satellites. Similar to the static positioning, the quad-constellation kinematic PPP also significantly improves the positioning performance in contrast with single-constellation and dual-constellations. The time varying characteristics of the time differences

  19. Single-point position and transition defects in continuous time quantum walks

    PubMed Central

    Li, Z. J.; Wang, J. B.

    2015-01-01

    We present a detailed analysis of continuous time quantum walks (CTQW) with both position and transition defects defined at a single point in the line. Analytical solutions of both traveling waves and bound states are obtained, which provide valuable insight into the dynamics of CTQW. The number of bound states is found to be critically dependent on the defect parameters, and the localized probability peaks can be readily obtained by projecting the state vector of CTQW on to these bound states. The interference between two bound states are also observed in the case of a transition defect. The spreading of CTQW probability over the line can be finely tuned by varying the position and transition defect parameters, offering the possibility of precision quantum control of the system. PMID:26323855

  20. Satellite- and Epoch Differenced Precise Point Positioning Based on a Regional Augmentation Network

    PubMed Central

    Li, Haojun; Chen, Junping; Wang, Jiexian; Wu, Bin

    2012-01-01

    Precise Point Positioning (PPP) has been demonstrated as a simple and effective approach for user positioning. The key issue in PPP is how to shorten convergence time and improve positioning efficiency. Recent researches mainly focus on the ambiguity resolution by correcting residual phase errors at a single station. The success of this approach (referred to hereafter as NORM-PPP) is subject to how rapidly one can fix wide-lane and narrow-lane ambiguities to achieve the first ambiguity-fixed solution. The convergence time of NORM-PPP is receiver type dependent, and normally takes 15–20 min. Different from the general algorithm and theory by which the float ambiguities are estimated and the integer ambiguities are fixed, we concentrate on a differential PPP approach: the satellite- and epoch differenced (SDED) approach. In general, the SDED approach eliminates receiver clocks and ambiguity parameters and thus avoids the complicated residual phase modeling procedure. As a further development of the SDED approach, we use a regional augmentation network to derive tropospheric delay and remaining un-modeled errors at user sites. By adding these corrections and applying the Robust estimation, the weak mathematic properties due to the ED operation is much improved. Implementing this new approach, we need only two epochs of data to achieve PPP positioning converging to centimeter-positioning accuracy. Using seven days of GPS data at six CORS stations in Shanghai, we demonstrate the success rate, defined as the case when three directions converging to desired positioning accuracy of 10 cm, reaches 100% when the interval between the two epochs is longer than 15 min. Comparing the results of 15 min' interval to that of 10 min', it is observed that the position RMS improves from 2.47, 3.95, 5.78 cm to 2.21, 3.93, 4.90 cm in the North, East and Up directions, respectively. Combining the SDED coordinates at the starting point and the ED relative coordinates thereafter, we

  1. The application of GPS precise point positioning technology in aerial triangulation

    NASA Astrophysics Data System (ADS)

    Yuan, Xiuxiao; Fu, Jianhong; Sun, Hongxing; Toth, Charles

    In traditional GPS-supported aerotriangulation, differential GPS (DGPS) positioning technology is used to determine the 3-dimensional coordinates of the perspective centers at exposure time with an accuracy of centimeter to decimeter level. This method can significantly reduce the number of ground control points (GCPs). However, the establishment of GPS reference stations for DGPS positioning is not only labor-intensive and costly, but also increases the implementation difficulty of aerial photography. This paper proposes aerial triangulation supported with GPS precise point positioning (PPP) as a way to avoid the use of the GPS reference stations and simplify the work of aerial photography. Firstly, we present the algorithm for GPS PPP in aerial triangulation applications. Secondly, the error law of the coordinate of perspective centers determined using GPS PPP is analyzed. Thirdly, based on GPS PPP and aerial triangulation software self-developed by the authors, four sets of actual aerial images taken from surveying and mapping projects, different in both terrain and photographic scale, are given as experimental models. The four sets of actual data were taken over a flat region at a scale of 1:2500, a mountainous region at a scale of 1:3000, a high mountainous region at a scale of 1:32000 and an upland region at a scale of 1:60000 respectively. In these experiments, the GPS PPP results were compared with results obtained through DGPS positioning and traditional bundle block adjustment. In this way, the empirical positioning accuracy of GPS PPP in aerial triangulation can be estimated. Finally, the results of bundle block adjustment with airborne GPS controls from GPS PPP are analyzed in detail. The empirical results show that GPS PPP applied in aerial triangulation has a systematic error of half-meter level and a stochastic error within a few decimeters. However, if a suitable adjustment solution is adopted, the systematic error can be eliminated in GPS

  2. Tightly Coupled Integration of Ionosphere-Constrained Precise Point Positioning and Inertial Navigation Systems

    PubMed Central

    Gao, Zhouzheng; Zhang, Hongping; Ge, Maorong; Niu, Xiaoji; Shen, Wenbin; Wickert, Jens; Schuh, Harald

    2015-01-01

    The continuity and reliability of precise GNSS positioning can be seriously limited by severe user observation environments. The Inertial Navigation System (INS) can overcome such drawbacks, but its performance is clearly restricted by INS sensor errors over time. Accordingly, the tightly coupled integration of GPS and INS can overcome the disadvantages of each individual system and together form a new navigation system with a higher accuracy, reliability and availability. Recently, ionosphere-constrained (IC) precise point positioning (PPP) utilizing raw GPS observations was proven able to improve both the convergence and positioning accuracy of the conventional PPP using ionosphere-free combined observations (LC-PPP). In this paper, a new mode of tightly coupled integration, in which the IC-PPP instead of LC-PPP is employed, is implemented to further improve the performance of the coupled system. We present the detailed mathematical model and the related algorithm of the new integration of IC-PPP and INS. To evaluate the performance of the new tightly coupled integration, data of both airborne and vehicle experiments with a geodetic GPS receiver and tactical grade inertial measurement unit are processed and the results are analyzed. The statistics show that the new approach can further improve the positioning accuracy compared with both IC-PPP and the tightly coupled integration of the conventional PPP and INS. PMID:25763647

  3. Modeling and Assessment of GPS/BDS Combined Precise Point Positioning

    PubMed Central

    Chen, Junping; Wang, Jungang; Zhang, Yize; Yang, Sainan; Chen, Qian; Gong, Xiuqiang

    2016-01-01

    Precise Point Positioning (PPP) technique enables stand-alone receivers to obtain cm-level positioning accuracy. Observations from multi-GNSS systems can augment users with improved positioning accuracy, reliability and availability. In this paper, we present and evaluate the GPS/BDS combined PPP models, including the traditional model and a simplified model, where the inter-system bias (ISB) is treated in different way. To evaluate the performance of combined GPS/BDS PPP, kinematic and static PPP positions are compared to the IGS daily estimates, where 1 month GPS/BDS data of 11 IGS Multi-GNSS Experiment (MGEX) stations are used. The results indicate apparent improvement of GPS/BDS combined PPP solutions in both static and kinematic cases, where much smaller standard deviations are presented in the magnitude distribution of coordinates RMS statistics. Comparisons between the traditional and simplified combined PPP models show no difference in coordinate estimations, and the inter system biases between the GPS/BDS system are assimilated into receiver clock, ambiguities and pseudo-range residuals accordingly. PMID:27455278

  4. Tightly coupled integration of ionosphere-constrained precise point positioning and inertial navigation systems.

    PubMed

    Gao, Zhouzheng; Zhang, Hongping; Ge, Maorong; Niu, Xiaoji; Shen, Wenbin; Wickert, Jens; Schuh, Harald

    2015-01-01

    The continuity and reliability of precise GNSS positioning can be seriously limited by severe user observation environments. The Inertial Navigation System (INS) can overcome such drawbacks, but its performance is clearly restricted by INS sensor errors over time. Accordingly, the tightly coupled integration of GPS and INS can overcome the disadvantages of each individual system and together form a new navigation system with a higher accuracy, reliability and availability. Recently, ionosphere-constrained (IC) precise point positioning (PPP) utilizing raw GPS observations was proven able to improve both the convergence and positioning accuracy of the conventional PPP using ionosphere-free combined observations (LC-PPP). In this paper, a new mode of tightly coupled integration, in which the IC-PPP instead of LC-PPP is employed, is implemented to further improve the performance of the coupled system. We present the detailed mathematical model and the related algorithm of the new integration of IC-PPP and INS. To evaluate the performance of the new tightly coupled integration, data of both airborne and vehicle experiments with a geodetic GPS receiver and tactical grade inertial measurement unit are processed and the results are analyzed. The statistics show that the new approach can further improve the positioning accuracy compared with both IC-PPP and the tightly coupled integration of the conventional PPP and INS. PMID:25763647

  5. Modeling and Assessment of GPS/BDS Combined Precise Point Positioning.

    PubMed

    Chen, Junping; Wang, Jungang; Zhang, Yize; Yang, Sainan; Chen, Qian; Gong, Xiuqiang

    2016-01-01

    Precise Point Positioning (PPP) technique enables stand-alone receivers to obtain cm-level positioning accuracy. Observations from multi-GNSS systems can augment users with improved positioning accuracy, reliability and availability. In this paper, we present and evaluate the GPS/BDS combined PPP models, including the traditional model and a simplified model, where the inter-system bias (ISB) is treated in different way. To evaluate the performance of combined GPS/BDS PPP, kinematic and static PPP positions are compared to the IGS daily estimates, where 1 month GPS/BDS data of 11 IGS Multi-GNSS Experiment (MGEX) stations are used. The results indicate apparent improvement of GPS/BDS combined PPP solutions in both static and kinematic cases, where much smaller standard deviations are presented in the magnitude distribution of coordinates RMS statistics. Comparisons between the traditional and simplified combined PPP models show no difference in coordinate estimations, and the inter system biases between the GPS/BDS system are assimilated into receiver clock, ambiguities and pseudo-range residuals accordingly. PMID:27455278

  6. GPS/GLONASS Combined Precise Point Positioning with Receiver Clock Modeling

    PubMed Central

    Wang, Fuhong; Chen, Xinghan; Guo, Fei

    2015-01-01

    Research has demonstrated that receiver clock modeling can reduce the correlation coefficients among the parameters of receiver clock bias, station height and zenith tropospheric delay. This paper introduces the receiver clock modeling to GPS/GLONASS combined precise point positioning (PPP), aiming to better separate the receiver clock bias and station coordinates and therefore improve positioning accuracy. Firstly, the basic mathematic models including the GPS/GLONASS observation equations, stochastic model, and receiver clock model are briefly introduced. Then datasets from several IGS stations equipped with high-stability atomic clocks are used for kinematic PPP tests. To investigate the performance of PPP, including the positioning accuracy and convergence time, a week of (1–7 January 2014) GPS/GLONASS data retrieved from these IGS stations are processed with different schemes. The results indicate that the positioning accuracy as well as convergence time can benefit from the receiver clock modeling. This is particularly pronounced for the vertical component. Statistic RMSs show that the average improvement of three-dimensional positioning accuracy reaches up to 30%–40%. Sometimes, it even reaches over 60% for specific stations. Compared to the GPS-only PPP, solutions of the GPS/GLONASS combined PPP are much better no matter if the receiver clock offsets are modeled or not, indicating that the positioning accuracy and reliability are significantly improved with the additional GLONASS satellites in the case of insufficient number of GPS satellites or poor geometry conditions. In addition to the receiver clock modeling, the impacts of different inter-system timing bias (ISB) models are investigated. For the case of a sufficient number of satellites with fairly good geometry, the PPP performances are not seriously affected by the ISB model due to the low correlation between the ISB and the other parameters. However, the refinement of ISB model weakens the

  7. GPS/GLONASS Combined Precise Point Positioning with Receiver Clock Modeling.

    PubMed

    Wang, Fuhong; Chen, Xinghan; Guo, Fei

    2015-01-01

    Research has demonstrated that receiver clock modeling can reduce the correlation coefficients among the parameters of receiver clock bias, station height and zenith tropospheric delay. This paper introduces the receiver clock modeling to GPS/GLONASS combined precise point positioning (PPP), aiming to better separate the receiver clock bias and station coordinates and therefore improve positioning accuracy. Firstly, the basic mathematic models including the GPS/GLONASS observation equations, stochastic model, and receiver clock model are briefly introduced. Then datasets from several IGS stations equipped with high-stability atomic clocks are used for kinematic PPP tests. To investigate the performance of PPP, including the positioning accuracy and convergence time, a week of (1-7 January 2014) GPS/GLONASS data retrieved from these IGS stations are processed with different schemes. The results indicate that the positioning accuracy as well as convergence time can benefit from the receiver clock modeling. This is particularly pronounced for the vertical component. Statistic RMSs show that the average improvement of three-dimensional positioning accuracy reaches up to 30%-40%. Sometimes, it even reaches over 60% for specific stations. Compared to the GPS-only PPP, solutions of the GPS/GLONASS combined PPP are much better no matter if the receiver clock offsets are modeled or not, indicating that the positioning accuracy and reliability are significantly improved with the additional GLONASS satellites in the case of insufficient number of GPS satellites or poor geometry conditions. In addition to the receiver clock modeling, the impacts of different inter-system timing bias (ISB) models are investigated. For the case of a sufficient number of satellites with fairly good geometry, the PPP performances are not seriously affected by the ISB model due to the low correlation between the ISB and the other parameters. However, the refinement of ISB model weakens the

  8. Stochastic modelling considering ionospheric scintillation effects on GNSS relative and point positioning

    NASA Astrophysics Data System (ADS)

    da Silva, Heloísa Alves; de Oliveira Camargo, Paulo; Galera Monico, João Francisco; Aquino, Marcio; Marques, Haroldo Antonio; de Franceschi, Giorgiana; Dodson, Alan

    2010-05-01

    a point positioning mode are presented and discussed. Two programs have been developed to enable the analyses: GPSeq (currently under development at the FCT/UNESP Sao Paulo State University - Brazil) and PP_Sc (developed in a collaborative project between FCT/UNESP and Nottingham University - UK). The point positioning approach is based on an epoch by epoch solution, whereas the relative positioning on an accumulated solution using a Kalman Filter and the LAMBDA method to solve the Double Differences ambiguities. Additionally to the use of an improved stochastic model, all data processing in this paper were performed using an option implemented in both programs, to estimate, for each observable, an individual ionospheric parameter modelled as a stochastic process, using either the white noise or the random walk correlation models. Data from a network of GPS Ionospheric Scintillation and TEC Monitor (GISTM) receivers set up in Northern Europe as part of the ISACCO project (De Franceschi et al., 2006) were used in the experiments. The point positioning results have shown improvements of the order of 45% in height accuracy when the proposed stochastic model is applied. In the static relative positioning, improvements of the order of 50%, also in height accuracy, have been reached under moderate to strong scintillation conditions. These and further results are discussed in this paper.

  9. Point detection and positioning system of the target based on surface cluster eyes

    NASA Astrophysics Data System (ADS)

    Guo, Fang; Zhang, Hao; Wang, Keyi

    2010-10-01

    The research of target detection and position is a challenge task in the fields where machine vision was used to develop various systems. However, monocular vision and binocular vision traditionally are difficult to meet the applications for high resolution and high sensitivity. Because compound eye imaging system is capacity of the large field of view for moving target detection with high sensitivity, the optical system has the potential to meet the applications above mentioned. In this paper, a preliminary exploration of the surface imaging system for the characteristics of cluster eyes was made and the optical signal processing methods of cluster eyes were introduced in detail. First the structure of the cluster eyes was described and the imaging channels of cluster eyes were ray traced with Zemax. Then based on the surface imaging mechanism with clusters eyes, the center of gravity of image space for target was extracted. Subsequently by the neural networks training based on LM (Levenberg-Marquardt) algorithm, the non-linear relationship between target and image was effectively calibrated. Finally, the corresponding relationship between target point and its image point among the various channels was established. The experimental results show that the multicast visual imaging systems are capable of providing the information of target azimuth and distance. Some attempts to study the systems were made to achieve high resolution, high sensitivity of target detection and positioning tasks. At the same time the surface imaging system also laid a solid foundation for the large compound eye imaging system from theory to practical application.

  10. [Neurological diseases after lightning strike : Lightning strikes twice].

    PubMed

    Gruhn, K M; Knossalla, Frauke; Schwenkreis, Peter; Hamsen, Uwe; Schildhauer, Thomas A; Tegenthoff, Martin; Sczesny-Kaiser, Matthias

    2016-06-01

    Lightning strikes rarely occur but 85 % of patients have lightning-related neurological complications. This report provides an overview about different modes of energy transfer and neurological conditions related to lightning strikes. Moreover, two case reports demonstrate the importance of interdisciplinary treatment and the spectrum of neurological complications after lightning strikes. PMID:26873252

  11. A method of undifferenced ambiguity resolution for GPS+GLONASS precise point positioning.

    PubMed

    Yi, Wenting; Song, Weiwei; Lou, Yidong; Shi, Chuang; Yao, Yibin

    2016-01-01

    Integer ambiguity resolution is critical for achieving positions of high precision and for shortening the convergence time of precise point positioning (PPP). However, GLONASS adopts the signal processing technology of frequency division multiple access and results in inter-frequency code biases (IFCBs), which are currently difficult to correct. This bias makes the methods proposed for GPS ambiguity fixing unsuitable for GLONASS. To realize undifferenced GLONASS ambiguity fixing, we propose an undifferenced ambiguity resolution method for GPS+GLONASS PPP, which considers the IFCBs estimation. The experimental result demonstrates that the success rate of GLONASS ambiguity fixing can reach 75% through the proposed method. Compared with the ambiguity float solutions, the positioning accuracies of ambiguity-fixed solutions of GLONASS-only PPP are increased by 12.2%, 20.9%, and 10.3%, and that of the GPS+GLONASS PPP by 13.0%, 35.2%, and 14.1% in the North, East and Up directions, respectively. PMID:27222361

  12. Assessment of Integer Precise Point Positioning performances at different temporal scales

    NASA Astrophysics Data System (ADS)

    Fund, F.; Perosanz, F.; Mercier, F.; Loyer, S.

    2012-04-01

    Recent improvements in Precise Point Positioning (PPP) including ambiguity resolution (Integer PPP; IPPP) make this technique a potential alternative to the classical differential approach. Single epoch positioning is also a powerful strategy to make GPS observation data screening. If all local earth deformations are correctly taken into account, residuals of position time series might be used to assess the processing quality in terms of receiver performance and local environment, constellation orbits and clocks error projection, and processing options pertinence. The aim of this presentation is to quantify current performances of PPP and IPPP at various temporal and spatial scales. We present what user should expect with respect to the classical double difference approach and what are the current noise characteristics of residual PPP time series. We use several geodetic GPS receivers located to different latitudes and suffer from different multipath situations and meteorological conditions. First, every situation is evaluated in terms of PPP performance with respect to double differences approach. Results are presented as a function of batch durations from hours to several days. Then, we show that GPS IPPP time series still suffer from various spurious signals (random, periodic, jumps...). Sometimes, errors clearly have a sidereal orbital period and a frequency analysis is provided. Also, artificial "midnight jumps" can be introduced when processing 24-hours batch solutions.

  13. A method of undifferenced ambiguity resolution for GPS+GLONASS precise point positioning

    PubMed Central

    Yi, Wenting; Song, Weiwei; Lou, Yidong; Shi, Chuang; Yao, Yibin

    2016-01-01

    Integer ambiguity resolution is critical for achieving positions of high precision and for shortening the convergence time of precise point positioning (PPP). However, GLONASS adopts the signal processing technology of frequency division multiple access and results in inter-frequency code biases (IFCBs), which are currently difficult to correct. This bias makes the methods proposed for GPS ambiguity fixing unsuitable for GLONASS. To realize undifferenced GLONASS ambiguity fixing, we propose an undifferenced ambiguity resolution method for GPS+GLONASS PPP, which considers the IFCBs estimation. The experimental result demonstrates that the success rate of GLONASS ambiguity fixing can reach 75% through the proposed method. Compared with the ambiguity float solutions, the positioning accuracies of ambiguity-fixed solutions of GLONASS-only PPP are increased by 12.2%, 20.9%, and 10.3%, and that of the GPS+GLONASS PPP by 13.0%, 35.2%, and 14.1% in the North, East and Up directions, respectively. PMID:27222361

  14. Triple positive solutions of three-point boundary value problems for p-Laplacian dynamic equations on time scales

    NASA Astrophysics Data System (ADS)

    Hong, Shihuang

    2007-09-01

    In this paper, we present sufficient conditions for the existence of at least three positive solutions of three-point boundary value problems for p-Laplacian dynamic equations on a time scale. To show our main results, we apply a new fixed point theorem due to Avery and Peterson [Three positive fixed points of nonlinear operators on ordered Banach spaces, Comput. Math. Appl. 42 (2001) 313-322].

  15. Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities

    PubMed Central

    Pan, Lin; Cai, Changsheng; Santerre, Rock; Zhu, Jianjun

    2014-01-01

    Precise point positioning (PPP) technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs) are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA) in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM) is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF). All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF. PMID:25237901

  16. Near-real-time regional troposphere models for the GNSS precise point positioning technique

    NASA Astrophysics Data System (ADS)

    Hadas, T.; Kaplon, J.; Bosy, J.; Sierny, J.; Wilgan, K.

    2013-05-01

    The GNSS precise point positioning (PPP) technique requires high quality product (orbits and clocks) application, since their error directly affects the quality of positioning. For real-time purposes it is possible to utilize ultra-rapid precise orbits and clocks which are disseminated through the Internet. In order to eliminate as many unknown parameters as possible, one may introduce external information on zenith troposphere delay (ZTD). It is desirable that the a priori model is accurate and reliable, especially for real-time application. One of the open problems in GNSS positioning is troposphere delay modelling on the basis of ground meteorological observations. Institute of Geodesy and Geoinformatics of Wroclaw University of Environmental and Life Sciences (IGG WUELS) has developed two independent regional troposphere models for the territory of Poland. The first one is estimated in near-real-time regime using GNSS data from a Polish ground-based augmentation system named ASG-EUPOS established by Polish Head Office of Geodesy and Cartography (GUGiK) in 2008. The second one is based on meteorological parameters (temperature, pressure and humidity) gathered from various meteorological networks operating over the area of Poland and surrounding countries. This paper describes the methodology of both model calculation and verification. It also presents results of applying various ZTD models into kinematic PPP in the post-processing mode using Bernese GPS Software. Positioning results were used to assess the quality of the developed models during changing weather conditions. Finally, the impact of model application to simulated real-time PPP on precision, accuracy and convergence time is discussed.

  17. GPS/GLONASS time offset monitoring based on combined Precise Point Positioning (PPP) approach

    NASA Astrophysics Data System (ADS)

    Huang, G.; Zhang, Q.; Fu, W.; Guo, H.

    2015-06-01

    A new strategy is proposed to monitor GPS/GLONASS time offsets for common navigation users using a combined GPS/GLONASS Precise Point Positioning (PPP) method based on the orbit and clock products of different time scales. The results of the inter-system GPS/GLONASS time offset, the user time offset and the inter-system device delay difference were obtained using the proposed method. The properties of these results were analyzed in terms of the stability, precision and variation characteristics. Moreover, the practicality of the time offset results in an actual navigation application was tested and demonstrated. The results indicate that the monitoring and prediction of the user time offset, but not the inter-system time offset, has important values for navigation users.

  18. Evaluation of single frequency GPS precise point positioning assisted with external ionosphere sources

    NASA Astrophysics Data System (ADS)

    Ghoddousi-Fard, Reza; Lahaye, François

    2016-05-01

    Single frequency code and single frequency code and phase GPS precise point positioning scenarios using various ionospheric sources are evaluated by assessing their performances with respect to dual frequency solutions. These include Canadian regional and global vertical total electron content (VTEC) maps produced by Natural Resources Canada and different International GNSS Service (IGS) coordination or analysis centres. Furthermore, two of the most commonly used single layer ionospheric mapping functions applied for conversion of VTEC to slant TEC are evaluated with each and every one of the ionospheric VTEC sources. Results show that the quality of code only solutions depends on ionospheric activity level, and the TEC map and mapping function selected. Code and phase single frequency solutions are also improved when assisted with an external ionosphere source.

  19. Differences in glenohumeral translations calculated with three methods: Comparison of relative positions and contact point.

    PubMed

    Matsuki, Keisuke; Kenmoku, Tomonori; Ochiai, Nobuyasu; Sugaya, Hiroyuki; Banks, Scott A

    2016-06-14

    Several published articles have reported 3-dimensional glenohumeral kinematics using model-image registration techniques. However, different methods to compute the translations were used in these articles. The purpose of this study was to compare glenohumeral translations calculated with three different methods. Fifteen healthy males with a mean age of 31 years (range, 27-36 years old) were enrolled in this study. Fluoroscopic images during scapular plane elevation were recorded at 30 frames per second for the right shoulder in each subject, and CT-derived models of the humerus and the scapula were matched with the silhouette of the bones in the fluoroscopic images using model-image registration techniques. Glenohumeral translations were computed with three methods: relative position of the origins of the humeral and scapular models, contact points of the two models, and relative positions based upon the calculated glenohumeral center of rotation (CoR). In the supero-inferior direction, translations calculated with the three methods were roughly parallel, with the maximum difference of 1.6mm (P<0.001). In the antero-posterior direction, translations with the origins and CoR were parallel; however, translations computed with the origins and contact point describe arcs that differ by almost 2mm at low humeral elevation angles and converge at higher degrees of humeral elevation (P<0.001). Glenohumeral translations calculated using three methods showed statistically significant differences that may be important when comparing detailed results of different studies. However, these relatively small differences are likely subclinical, so that all three methods can reasonably be used for description of glenohumeral translations. PMID:27083061

  20. The Pullman Strike of 1894.

    ERIC Educational Resources Information Center

    Bassett, Jonathan

    1997-01-01

    Presents a lesson plan focused on the events surrounding the 1894 Pullman railroad car strike. Reviews the particulars of the strike (the federal government used armed force to end the strike) and then presents a simulation where students role play members of the investigating presidential commission. Includes related documents. (MJP)

  1. Clusterless Decoding of Position From Multiunit Activity Using A Marked Point Process Filter

    PubMed Central

    Deng, Xinyi; Liu, Daniel F.; Kay, Kenneth; Frank, Loren M.; Eden, Uri T.

    2016-01-01

    Point process filters have been applied successfully to decode neural signals and track neural dynamics. Traditionally, these methods assume that multiunit spiking activity has already been correctly spike-sorted. As a result, these methods are not appropriate for situations where sorting cannot be performed with high precision such as real-time decoding for brain-computer interfaces. As the unsupervised spike-sorting problem remains unsolved, we took an alternative approach that takes advantage of recent insights about clusterless decoding. Here we present a new point process decoding algorithm that does not require multiunit signals to be sorted into individual units. We use the theory of marked point processes to construct a function that characterizes the relationship between a covariate of interest (in this case, the location of a rat on a track) and features of the spike waveforms. In our example, we use tetrode recordings, and the marks represent a four-dimensional vector of the maximum amplitudes of the spike waveform on each of the four electrodes. In general, the marks may represent any features of the spike waveform. We then use Bayes’ rule to estimate spatial location from hippocampal neural activity. We validate our approach with a simulation study and with experimental data recorded in the hippocampus of a rat moving through a linear environment. Our decoding algorithm accurately reconstructs the rat’s position from unsorted multiunit spiking activity. We then compare the quality of our decoding algorithm to that of a traditional spike-sorting and decoding algorithm. Our analyses show that the proposed decoding algorithm performs equivalently or better than algorithms based on sorted single-unit activity. These results provide a path toward accurate real-time decoding of spiking patterns that could be used to carry out content-specific manipulations of population activity in hippocampus or elsewhere in the brain. PMID:25973549

  2. Ophthalmic manifestations postlightning strike.

    PubMed

    Dhillon, Permesh Singh; Gupta, Mohit

    2015-01-01

    Various ophthalmic complications affecting the anterior and posterior segments have been identified due to lightning strike. We report the first case of an indirect lightning-induced full thickness macular hole formation in the UK as evidenced by slit lamp examination and optical coherence tomography (OCT) scan in a 77-year-old woman presenting with sudden visual loss in her right eye and thermal skin injury affecting her scalp. Her best corrected visual acuities were LogMAR 0.46 and 0.12 in the right and left eyes, respectively. There were no other ocular manifestations observed in either eye. She was initially managed conservatively with non-steroidal anti-inflammatory drug eye drops but surgery was later advised due to minimal changes in the visual acuity and macular hole on follow-up. OCT scanning is important in diagnosing macular holes, which usually warrant surgical intervention. PMID:25827914

  3. Evaluation of Precise Point Positioning accuracy under large total electron content variations in equatorial latitudes

    NASA Astrophysics Data System (ADS)

    Rodríguez-Bilbao, I.; Moreno Monge, B.; Rodríguez-Caderot, G.; Herraiz, M.; Radicella, S. M.

    2015-01-01

    The ionosphere is one of the largest contributors to errors in GNSS positioning. Although in Precise Point Positioning (PPP) the ionospheric delay is corrected to a first order through the 'iono-free combination', significant errors may still be observed when large electron density gradients are present. To confirm this phenomenon, the temporal behavior of intense fluctuations of total electron content (TEC) and PPP altitude accuracy at equatorial latitudes are analyzed during four years of different solar activity. For this purpose, equatorial plasma irregularities are identified with periods of high rate of change of TEC (ROT). The largest ROT values are observed from 19:00 to 01:00 LT, especially around magnetic equinoxes, although some differences exist between the stations depending on their location. Highest ROT values are observed in the American and African regions. In general, large ROT events are accompanied by frequent satellite signal losses and an increase in the PPP altitude error during years 2001, 2004 and 2011. A significant increase in the PPP altitude error RMS is observed in epochs of high ROT with respect to epochs of low ROT in years 2001, 2004 and 2011, reaching up to 0.26 m in the 19:00-01:00 LT period.

  4. Striking Down the Communications Decency Act.

    ERIC Educational Resources Information Center

    Russo, Charles J.

    1998-01-01

    The Supreme Court's decision in "Reno," striking down major portions of the Communications Decency Act of 1996, pits the need to protect children from inappropriate material against the need to maintain free Internet access by adults. Highlights major points in the holding and discusses the meaning of "Reno" for educators. (MLF)

  5. Impact of orbit, clock and EOP errors in GNSS Precise Point Positioning

    NASA Astrophysics Data System (ADS)

    Hackman, C.

    2012-12-01

    Precise point positioning (PPP; [1]) has gained ever-increasing usage in GNSS carrier-phase positioning, navigation and timing (PNT) since its inception in the late 1990s. In this technique, high-precision satellite clocks, satellite ephemerides and earth-orientation parameters (EOPs) are applied as fixed input by the user in order to estimate receiver/location-specific quantities such as antenna coordinates, troposphere delay and receiver-clock corrections. This is in contrast to "network" solutions, in which (typically) less-precise satellite clocks, satellite ephemerides and EOPs are used as input, and in which these parameters are estimated simultaneously with the receiver/location-specific parameters. The primary reason for increased PPP application is that it offers most of the benefits of a network solution with a smaller computing cost. In addition, the software required to do PPP positioning can be simpler than that required for network solutions. Finally, PPP permits high-precision positioning of single or sparsely spaced receivers that may have few or no GNSS satellites in common view. A drawback of PPP is that the accuracy of the results depend directly on the accuracy of the supplied orbits, clocks and EOPs, since these parameters are not adjusted during the processing. In this study, we will examine the impact of orbit, EOP and satellite clock estimates on PPP solutions. Our primary focus will be the impact of these errors on station coordinates; however the study may be extended to error propagation into receiver-clock corrections and/or troposphere estimates if time permits. Study motivation: the United States Naval Observatory (USNO) began testing PPP processing using its own predicted orbits, clocks and EOPs in Summer 2012 [2]. The results of such processing could be useful for real- or near-real-time applications should they meet accuracy/precision requirements. Understanding how errors in satellite clocks, satellite orbits and EOPs propagate

  6. Geodetic point positioning with GPS (Global Positioning System) carrier beat phase data from the CASA (Central and South America) Uno experiment

    SciTech Connect

    Malys, S.; Jensen, P.A. )

    1990-04-01

    The Global Positioning System (GPS) carrier beat phase data collected by the TI4100 GPS receiver has been successfully utilized by the US Defense Mapping Agency in an algorithm which is designed to estimate individual absolute geodetic point positions from data collected over a few hours. The algorithm uses differenced data from one station and two to four GPS satellites at a series of epochs separated by 30 second intervals. The precise GPS ephemerides and satellite clock states, held fixed in the estimation process, are those estimated by the Naval Surface Warfare Center (NSWC). Broadcast ephemerides and clock states are also utilized for comparative purposes. An outline of the data corrections applied, the mathematical model and the estimation algorithm are presented. Point positioning results and statistics are presented for a globally-distributed set of stations which contributed to the CASA Uno experiment. Statistical assessment of 114 GPS point positions at 11 CASA Uno stations indicates that the overall standard deviation of a point position component, estimated from a few hours of data, is 73 centimeters. Solution of the long line geodetic inverse problem using repeated point positions such as these can potentially offer a new tool for those studying geodynamics on a global scale.

  7. Precise Point Positioning with Ionosphere Estimation and application of Regional Ionospheric Maps

    NASA Astrophysics Data System (ADS)

    Galera Monico, J. F.; Marques, H. A.; Rocha, G. D. D. C.

    2015-12-01

    The ionosphere is one of most difficult source of errors to be modelled in the GPS positioning, mainly when applying data collected by single frequency receivers. Considering Precise Point Positioning (PPP) with single frequency data the options available include, for example, the use of Klobuchar model or applying Global Ionosphere Maps (GIM). The GIM contains Vertical Electron Content (VTEC) values that are commonly estimated considering a global network with poor covering in certain regions. For this reason Regional Ionosphere Maps (RIM) have been developed considering local GNSS network, for instance, the La Plata Ionospheric Model (LPIM) developed inside the context of SIRGAS (Geocentric Reference System for Americas). The South American RIM are produced with data from nearly 50 GPS ground receivers and considering these maps are generated for each hour with spatial resolution of one degree it is expected to provide better accuracy in GPS positioning for such region. Another possibility to correct for ionosphere effects in the PPP is to apply the ionosphere estimation technique based on Kalman filter. In this case, the ionosphere can be treated as a stochastic process and a good initial guess is necessary what can be obtained from an ionospheric map. In this paper we present the methodology involved with ionosphere estimation by using Kalman filter and also the application of global and regional ionospheric maps in the PPP as first guess. The ionosphere estimation strategy was implemented in the house software called RT_PPP that is capable of accomplishing PPP either for single or dual frequency data. GPS data from Brazilian station near equatorial region were processed and results with regional maps were compared with those by using global maps. Improvements of the order 15% were observed. In case of ionosphere estimation, the estimated coordinates were compared with ionosphere free solution and after PPP convergence the results reached centimeter accuracy.

  8. Integration of GPS Precise Point Positioning and MEMS-Based INS Using Unscented Particle Filter

    PubMed Central

    Abd Rabbou, Mahmoud; El-Rabbany, Ahmed

    2015-01-01

    Integration of Global Positioning System (GPS) and Inertial Navigation System (INS) integrated system involves nonlinear motion state and measurement models. However, the extended Kalman filter (EKF) is commonly used as the estimation filter, which might lead to solution divergence. This is usually encountered during GPS outages, when low-cost micro-electro-mechanical sensors (MEMS) inertial sensors are used. To enhance the navigation system performance, alternatives to the standard EKF should be considered. Particle filtering (PF) is commonly considered as a nonlinear estimation technique to accommodate severe MEMS inertial sensor biases and noise behavior. However, the computation burden of PF limits its use. In this study, an improved version of PF, the unscented particle filter (UPF), is utilized, which combines the unscented Kalman filter (UKF) and PF for the integration of GPS precise point positioning and MEMS-based inertial systems. The proposed filter is examined and compared with traditional estimation filters, namely EKF, UKF and PF. Tightly coupled mechanization is adopted, which is developed in the raw GPS and INS measurement domain. Un-differenced ionosphere-free linear combinations of pseudorange and carrier-phase measurements are used for PPP. The performance of the UPF is analyzed using a real test scenario in downtown Kingston, Ontario. It is shown that the use of UPF reduces the number of samples needed to produce an accurate solution, in comparison with the traditional PF, which in turn reduces the processing time. In addition, UPF enhances the positioning accuracy by up to 15% during GPS outages, in comparison with EKF. However, all filters produce comparable results when the GPS measurement updates are available. PMID:25815446

  9. Integration of GPS precise point positioning and MEMS-based INS using unscented particle filter.

    PubMed

    Abd Rabbou, Mahmoud; El-Rabbany, Ahmed

    2015-01-01

    Integration of Global Positioning System (GPS) and Inertial Navigation System (INS) integrated system involves nonlinear motion state and measurement models. However, the extended Kalman filter (EKF) is commonly used as the estimation filter, which might lead to solution divergence. This is usually encountered during GPS outages, when low-cost micro-electro-mechanical sensors (MEMS) inertial sensors are used. To enhance the navigation system performance, alternatives to the standard EKF should be considered. Particle filtering (PF) is commonly considered as a nonlinear estimation technique to accommodate severe MEMS inertial sensor biases and noise behavior. However, the computation burden of PF limits its use. In this study, an improved version of PF, the unscented particle filter (UPF), is utilized, which combines the unscented Kalman filter (UKF) and PF for the integration of GPS precise point positioning and MEMS-based inertial systems. The proposed filter is examined and compared with traditional estimation filters, namely EKF, UKF and PF. Tightly coupled mechanization is adopted, which is developed in the raw GPS and INS measurement domain. Un-differenced ionosphere-free linear combinations of pseudorange and carrier-phase measurements are used for PPP. The performance of the UPF is analyzed using a real test scenario in downtown Kingston, Ontario. It is shown that the use of UPF reduces the number of samples needed to produce an accurate solution, in comparison with the traditional PF, which in turn reduces the processing time. In addition, UPF enhances the positioning accuracy by up to 15% during GPS outages, in comparison with EKF. However, all filters produce comparable results when the GPS measurement updates are available. PMID:25815446

  10. Foot-strike pattern and performance in a marathon

    PubMed Central

    Kasmer, Mark E.; Liu, Xue-cheng; Roberts, Kyle G.; Valadao, Jason M.

    2016-01-01

    Purpose To: 1) determine prevalence of heel-strike in a mid-size city marathon, 2) determine if there is an association between foot-strike classification and race performance, and 3) determine if there is an association between foot-strike classification and gender. Methods Foot-strike classification (fore-foot strike, mid-foot strike, heel strike, or split-strike), gender, and rank (position in race) were recorded at the 8.1 kilometer (km) mark for 2,112 runners at the 2011 Milwaukee Lakefront Marathon. Results 1,991 runners were classified by foot-strike pattern, revealing a heel-strike prevalence of 93.67% (n=1,865). A significant difference between foot-strike classification and performance was found using a Kruskal-Wallis test (p < 0.0001), with more elite performers being less likely to heel-strike. No significant difference between foot-strike classification and gender was found using a Fisher’s exact test. Additionally, subgroup analysis of the 126 non-heel strikers found no significant difference between shoe wear and performance using a Kruskal-Wallis test. Conclusions The high prevalence of heel-striking observed in this study reflects the foot-strike pattern of the majority of mid- to long-distance runners and more importantly, may predict their injury profile based on the biomechanics of a heel strike running pattern. This knowledge can aid the clinician in the appropriate diagnosis, management, and training modifications of the injured runner. PMID:23006790

  11. GPS Seismology: Using Precise Point Positioning for Resolving Surface Wave Displacements from Large Earthquakes

    NASA Astrophysics Data System (ADS)

    Dragert, H.; Henton, J. A.; Lahaye, F.; Kouba, J.; Larson, K. M.; Rogers, G. C.

    2010-12-01

    High-rate continuous GPS data can provide direct, high-quality measurements of surface wave displacements generated by large earthquakes (Larson et al., 2003; Bock et al., 2004; Larson, 2009). To achieve high precision, differential positioning is often used in the GPS analysis strategy with distant reference stations held fixed. In this presentation, we examine the use of the Precise Point Positioning (PPP) technique to estimate epoch-by-epoch positions at single stations. Specifically, we use the PPP software developed by Natural Resources Canada (Heroux and Kouba, 2001) to analyze high-rate (5 Hz) GPS data collected at stations of the Plate Boundary Observatory (PBO) in southern California at the time of the M7.2 El Mayor-Cucapah Earthquake of April 4, 2010. The hypocenter for this earthquake was located in northern Baja California, approximately 50 km south of Mexicali on the US-Mexico border, at a depth of ~10 km. Large horizontal displacements were observed at a number of PBO GPS sites, with the largest peak-to-peak displacements exceeding 90 cm in the east-west component for 10-sec period waves observed at El Centro, CA (P496), located about 70 km northeast of the epicenter. The PPP technique clearly resolved surface waves with 1 to 2 cm amplitudes at sites more than 800 km away from the epicenter, illustrating that surface waves eventually reach even distant reference sites within the period of interest and can thereby introduce artifacts for differential GPS positioning. Fine-tuning of PPP methodology revealed the following: 1) Since the quality of a PPP solution will not be optimal until the carrier phase ambiguities have converged (tens of minutes), it is best to begin the analyses well before the arrival of seismic waves. To reduce computations, the data for this convergence period need not be high-rate; 2) The use of 5-second precise satellite clock sampling instead of the nominal 30-second clock sampling minimized clock interpolation errors and

  12. On troposphere delay constraining in real-time GNSS Precise Point Positioning

    NASA Astrophysics Data System (ADS)

    Hadas, Tomasz; Kazmierski, Kamil; Bosy, Jaroslaw

    2015-04-01

    A common procedure in Precise Point Positioning (PPP) is to have the adjustment model accounting for the correction to an a priori value of the total troposphere delay (ZTD) given at the first epoch of data processing, and the troposphere wet delay filter is updated epoch by epoch. This approach requires some time so that a change in satellite geometry allows to efficiently de-correlate among tropospheric delay, receiver clock error and height. Empirical troposphere state models and mapping functions are available, however they may not reflect properly the actual state of the troposphere, especially in severe weather conditions. It might be more appropriate to take advantage on a regional troposphere model derived from near real-time (NRT) processing of GBAS network. To evaluate the impact of troposphere constraining in real-time PPP, one week long period was selected, that was characterized with active troposphere conditions. Using the development version of original GNSS-WARP software, a 1 Hz kinematic positioning was performed for 10 selected Polish GBAS stations using IGS Real-Time Service (RTS) products. Two processing strategies were used, one reflecting the common PPP approach and the second with NRT ZTD to constrain the troposphere delay estimates. GPS only and GPS+GLONASS positioning was performed and analyzed using both strategies. For unconstrained solutions, the convergence time of one hour (GPS only) and 15 minutes (GPS+GLONASS) was reached, providing the sub-decimeter accuracy in horizontal and vertical component. However, for some epochs, and outlying height estimates were observed with the residuals reaching up to 0.5m with the estimated error of 0.2m. At the same time, the unconstrained estimated troposphere delay differs up to 12 cm from the reference NRT ZTD solution. In case the troposphere delay is constrained, all three coordinate components remains accurate and precise for entire processing period after the convergence is reached. From the

  13. The fork in the road: HIV as a potential positive turning point and the role of spirituality.

    PubMed

    Kremer, H; Ironson, G; Kaplan, L

    2009-03-01

    We interviewed 147 HIV-positive people regarding their key life-changing experiences - involving profound changes in attitudes, behaviors, beliefs (including spiritual beliefs), or self-views - to determine the prominence of HIV as the key positive/negative turning point. HIV was the key turning point, for 37% (26% positive, 11% negative), whereas for 63% of our sample it was not. Characteristics associated with perceiving HIV as the most positive turning point included having a near-death experience from HIV, increasing spirituality after HIV diagnosis, and feeling chosen by a Higher Powerto have HIV. Notably, perceived antecedents of viewing HIV as the key positive turning point were hitting rock bottom and calling on a Higher Power. Conversely, viewing HIV as the most negative turning point was associated with declining spirituality after diagnosis. Spirituality can both negatively and positively affect coping with HIV. Promoting positive spiritual coping may offer new counseling approaches. Further, for the majority of the participants, HIV is not the key turning point, which may be an indicator of the normalization of HIV with the advent of effective treatment. PMID:19280412

  14. An Investigation on the Reliability of Deformation Analysis at Simulated Network Depending on the Precise Point Position Technique

    NASA Astrophysics Data System (ADS)

    Durdag, U. M.; Erdogan, B.; Hekimoglu, S.

    2014-12-01

    Deformation analysis plays an important role for human life safety; hence investigating the reliability of the obtained results from deformation analysis is crucial. The deformation monitoring network is established and the observations are analyzed periodically. The main problem in the deformation analysis is that if there is more than one displaced point in the monitoring network, the analysis methods smear the disturbing effects of the displaced points over all other points which are not displaced. Therefore, only one displaced point can be detected successfully. The Precise Point Positioning (PPP) gives opportunity to prevent smearing effect of the displaced points. In this study, we have simulated a monitoring network that consisting four object points and generated six different scenarios. The displacements were added to the points by using a device that the GPS antenna was easily moved horizontally and the seven hours static GPS measurements were carried out. The measurements were analyzed by using online Automatic Precise Positioning Service (APPS) to obtain the coordinates and covariance matrices. The results of the APPS were used in the deformation analysis. The detected points and true displaced points were compared with each other to obtain reliability of the method. According to the results, the analysis still detect stable points as displaced points. For the next step, we are going to search the reason of the wrong results and deal with acquiring more reliable results.

  15. Determination of earthquake magnitude using GPS displacement waveforms from real-time precise point positioning

    NASA Astrophysics Data System (ADS)

    Fang, Rongxin; Shi, Chuang; Song, Weiwei; Wang, Guangxing; Liu, Jingnan

    2014-01-01

    For earthquake and tsunami early warning and emergency response, earthquake magnitude is the crucial parameter to be determined rapidly and correctly. However, a reliable and rapid measurement of the magnitude of an earthquake is a challenging problem, especially for large earthquakes (M > 8). Here, the magnitude is determined based on the GPS displacement waveform derived from real-time precise point positioning (RTPPP). RTPPP results are evaluated with an accuracy of 1 cm in the horizontal components and 2-3 cm in the vertical components, indicating that the RTPPP is capable of detecting seismic waves with amplitude of 1 cm horizontally and 2-3 cm vertically with a confidence level of 95 per cent. In order to estimate the magnitude, the unique information provided by the GPS displacement waveform is the horizontal peak displacement amplitude. We show that the empirical relation of Gutenberg (1945) between peak displacement and magnitude holds up to nearly magnitude 9.0 when displacements are measured with GPS. We tested the proposed method for three large earthquakes. For the 2010 Mw 7.2 El Mayor-Cucapah earthquake, our method provides a magnitude of M7.18 ± 0.18. For the 2011 Mw 9.0 Tohoku-oki earthquake the estimated magnitude is M8.74 ± 0.06, and for the 2010 Mw 8.8 Maule earthquake the value is M8.7 ± 0.1 after excluding some near-field stations. We, therefore, conclude that depending on the availability of high-rate GPS observations, a robust value of magnitude up to 9.0 for a point source earthquake can be estimated within tens of seconds or a few minutes after an event using a few GPS stations close to the epicentre. The rapid magnitude could be as a pre-requisite for tsunami early warning, fast source inversion and emergency response is feasible.

  16. A simplified and unified model of multi-GNSS precise point positioning

    NASA Astrophysics Data System (ADS)

    Chen, Junping; Zhang, Yize; Wang, Jungang; Yang, Sainan; Dong, Danan; Wang, Jiexian; Qu, Weijing; Wu, Bin

    2015-01-01

    Additional observations from other GNSS s can augment GPS precise point positioning (PPP) for improved positioning accuracy, reliability and availability. Traditional multi-GNSS PPP model requires the estimation of inter-system bias (ISB) parameter. Based on the scaled sensitivity matrix (SSM) method, a quantitative approach for assessing parameter assimilation, we theoretically prove that the ISB parameter is not correlated with coordinate parameters and it can be assimilated into clock and ambiguity parameters. Thus, removing ISB from multi-GNSS PPP model does not affect coordinate estimation. Based on this analysis, we develop a simplified and unified model for multi-GNSS PPP, where ISB parameter does not need to be estimated and observations from different GNSS systems are treated in a unified way. To verify the new model, we implement the algorithm to the self-developed software to process 1 year GPS/GLONASS data of 53 IGS (International GNSS Service) worldwide stations and 1 month GPS/BDS data of 15 IGS MGEX (Multi-GNSS Experiment) stations. Two types of GPS/GLONASS and GPS/BDS combined PPP solution are performed, one is based on traditional model and the other implements the new model. RMSs of coordinate differences between the two type of solutions are few μm for daily static PPP and less than 0.02 mm for GPS/GLONASS kinematic PPP in the North, East and Up components, respectively. Considering the millimeter-level precision of current GNSS PPP solutions, these statistics demonstrate equivalent performance of the two solution types.

  17. Ambiguity resolution in precise point positioning with hourly data for global single receiver

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohong; Li, Pan; Guo, Fei

    2013-01-01

    Integer ambiguity resolution (IAR) can improve precise point positioning (PPP) performance significantly. IAR for PPP became a highlight topic in global positioning system (GPS) community in recent years. More and more researchers focus on this issue. Progress has been made in the latest years. In this paper, we aim at investigating and demonstrating the performance of a global zero-differenced (ZD) PPP IAR service for GPS users by providing routine ZD uncalibrated fractional offsets (UFOs) for wide-lane and narrow-lane. Data sets from all IGS stations collected on DOY 1, 100, 200 and 300 of 2010 are used to validate and demonstrate this global service. Static experiment results show that an accuracy better than 1 cm in horizontal and 1-2 cm in vertical could be achieved in ambiguity-fixed PPP solution with only hourly data. Compared with PPP float solution, an average improvement reaches 58.2% in east, 28.3% in north and 23.8% in vertical for all tested stations. Results of kinematic experiments show that the RMS of kinematic PPP solutions can be improved from 21.6, 16.6 and 37.7 mm to 12.2, 13.3 and 34.3 mm for the fixed solutions in the east, north and vertical components, respectively. Both static and kinematic experiments show that wide-lane and narrow-lane UFO products of all satellites can be generated and provided in a routine way accompanying satellite orbit and clock products for the PPP user anywhere around the world, to obtain accurate and reliable ambiguity-fixed PPP solutions.

  18. Integrity monitoring in real-time precise point positioning in the presence of ionospheric disturbances

    NASA Astrophysics Data System (ADS)

    Wezka, K.; Galas, R.

    2013-12-01

    Ionospheric disturbances are characterized as fast and random variability in the ionosphere. Those phenomena are difficult to predict, detect and model. Occurrence of some strong ionospheric disturbances can cause, inter alia degradation and interruption of GNSS signals. Therefore they are especially harmful for real-time applications, as for example Precise Point Positioning (PPP) in real time, where one of the most important requirements is to ensure the high level of reliability. In such applications verification and confirmation of a high trust degree towards the estimated coordinates is a very critical issue. In one of the previous papers (K. Wezka, 2012 -Identification of system performance parameters and their usability) two sets of parameters have been proposed for enhance reliability of the PPP. The first one for data quality control (QC) of the raw GNSS observations and the second one for examination of the quality, robustness and performance of various processing approaches (strategies). To the second group the following parameters has been proposed: accuracy, precision, availability, integrity and convergence time. In consideration of perturbation of GNSS signal resulting from sudden ionospheric disturbances, one of the most important demands is effective autonomous integrity monitoring. The poster presents first preliminary results of the applicability of the proposed parameters in order to ensure the high level of reliability/integrity of GNSS observations and positioning results under the presence of strong ionospheric anomalies. The data-set from continuously operated GNSS station located at high latitude, where ionospheric disturbances occur more frequently, were used for the analysis. Various selected Receiver Autonomous Integrity Monitoring (RAIM) approaches for quality control of the GNSS observables are applied to the data sets recorded under different (low/quite and high) ionospheric activities. Based on those analyses the usability of the

  19. Where Lightning Strikes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Lightning. It avoids the ocean, but likes Florida. It's attracted to the Himalayas and even more so to central Africa. And lightning almost never strikes the north or south poles. These are just a few of the things NASA scientists have learned using satellites to monitor worldwide lightning. 'For the first time, we've been able to map the global distribution of lightning, noting its variation as a function of latitude, longitude and time of year,' says Hugh Christian, project leader for the National Space Science and Technology Center's (NSSTC's) lightning team at NASA's Marshall Space Flight Center. This new perspective on lightning is possible thanks to two satellite-based detectors: the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS). 'The OTD and the LIS are two optical sensors that we've flown in lower Earth orbit,' says Christian, whose team developed the sensors. 'The OTD was launched in 1995 and we got five good years out of it. The LIS was launched on the Tropical Rainfall Measuring Mission satellite in 1997 and it's still going strong.' 'Basically, these optical sensors use high-speed cameras to look for changes in the tops of clouds, changes your eyes can't see,' he explains. By analyzing a narrow wavelength band around 777 nanometers-which is in the near-infrared region of the spectrum-they can spot brief lightning flashes even under daytime conditions. For the full story, visit Science@NASA Image courtesy NSSTC Lightning Team

  20. Ambiguity resolved precise point positioning with GPS and BeiDou

    NASA Astrophysics Data System (ADS)

    Pan, Li; Xiaohong, Zhang; Fei, Guo

    2016-07-01

    This paper focuses on the contribution of the global positioning system (GPS) and BeiDou navigation satellite system (BDS) observations to precise point positioning (PPP) ambiguity resolution (AR). A GPS + BDS fractional cycle bias (FCB) estimation method and a PPP AR model were developed using integrated GPS and BDS observations. For FCB estimation, the GPS + BDS combined PPP float solutions of the globally distributed IGS MGEX were first performed. When integrating GPS observations, the BDS ambiguities can be precisely estimated with less than four tracked BDS satellites. The FCBs of both GPS and BDS satellites can then be estimated from these precise ambiguities. For the GPS + BDS combined AR, one GPS and one BDS IGSO or MEO satellite were first chosen as the reference satellite for GPS and BDS, respectively, to form inner-system single-differenced ambiguities. The single-differenced GPS and BDS ambiguities were then fused by partial ambiguity resolution to increase the possibility of fixing a subset of decorrelated ambiguities with high confidence. To verify the correctness of the FCB estimation and the effectiveness of the GPS + BDS PPP AR, data recorded from about 75 IGS MGEX stations during the period of DOY 123-151 (May 3 to May 31) in 2015 were used for validation. Data were processed with three strategies: BDS-only AR, GPS-only AR and GPS + BDS AR. Numerous experimental results show that the time to first fix (TTFF) is longer than 6 h for the BDS AR in general and that the fixing rate is usually less than 35 % for both static and kinematic PPP. An average TTFF of 21.7 min and 33.6 min together with a fixing rate of 98.6 and 97.0 % in static and kinematic PPP, respectively, can be achieved for GPS-only ambiguity fixing. For the combined GPS + BDS AR, the average TTFF can be shortened to 16.9 min and 24.6 min and the fixing rate can be increased to 99.5 and 99.0 % in static and kinematic PPP, respectively. Results also show that GPS + BDS PPP AR outperforms

  1. On biases in precise point positioning with multi-constellation and multi-frequency GNSS data

    NASA Astrophysics Data System (ADS)

    El-Mowafy, A.; Deo, M.; Rizos, C.

    2016-03-01

    Various types of biases in Global Navigation Satellite System (GNSS) data preclude integer ambiguity fixing and degrade solution accuracy when not being corrected during precise point positioning (PPP). In this contribution, these biases are first reviewed, including satellite and receiver hardware biases, differential code biases, differential phase biases, initial fractional phase biases, inter-system receiver time biases, and system time scale offset. PPP models that take account of these biases are presented for two cases using ionosphere-free observations. The first case is when using primary signals that are used to generate precise orbits and clock corrections. The second case applies when using additional signals to the primary ones. In both cases, measurements from single and multiple constellations are addressed. It is suggested that the satellite-related code biases be handled as calibrated quantities that are obtained from multi-GNSS experiment products and the fractional phase cycle biases obtained from a network to allow for integer ambiguity fixing. Some receiver-related biases are removed using between-satellite single differencing, whereas other receiver biases such as inter-system biases are lumped with differential code and phase biases and need to be estimated. The testing results show that the treatment of biases significantly improves solution convergence in the float ambiguity PPP mode, and leads to ambiguity-fixed PPP within a few minutes with a small improvement in solution precision.

  2. Accuracy improvement techniques in Precise Point Positioning method using multiple GNSS constellations

    NASA Astrophysics Data System (ADS)

    Vasileios Psychas, Dimitrios; Delikaraoglou, Demitris

    2016-04-01

    The future Global Navigation Satellite Systems (GNSS), including modernized GPS, GLONASS, Galileo and BeiDou, offer three or more signal carriers for civilian use and much more redundant observables. The additional frequencies can significantly improve the capabilities of the traditional geodetic techniques based on GPS signals at two frequencies, especially with regard to the availability, accuracy, interoperability and integrity of high-precision GNSS applications. Furthermore, highly redundant measurements can allow for robust simultaneous estimation of static or mobile user states including more parameters such as real-time tropospheric biases and more reliable ambiguity resolution estimates. This paper presents an investigation and analysis of accuracy improvement techniques in the Precise Point Positioning (PPP) method using signals from the fully operational (GPS and GLONASS), as well as the emerging (Galileo and BeiDou) GNSS systems. The main aim was to determine the improvement in both the positioning accuracy achieved and the time convergence it takes to achieve geodetic-level (10 cm or less) accuracy. To this end, freely available observation data from the recent Multi-GNSS Experiment (MGEX) of the International GNSS Service, as well as the open source program RTKLIB were used. Following a brief background of the PPP technique and the scope of MGEX, the paper outlines the various observational scenarios that were used in order to test various data processing aspects of PPP solutions with multi-frequency, multi-constellation GNSS systems. Results from the processing of multi-GNSS observation data from selected permanent MGEX stations are presented and useful conclusions and recommendations for further research are drawn. As shown, data fusion from GPS, GLONASS, Galileo and BeiDou systems is becoming increasingly significant nowadays resulting in a position accuracy increase (mostly in the less favorable East direction) and a large reduction of convergence

  3. Pattern of dynamic displacements in a strike-slip earthquake

    NASA Astrophysics Data System (ADS)

    Saltogianni, V.; Gianniou, M.; Moschas, F.; Stiros, S.

    2016-07-01

    High-rate (1 Hz) records from GPS stations uniformly distributed along the fault ruptures of the 2014 Samothraki-Gökçeada Mw6.9 earthquake in the North Aegean Trough, at the extension of the North Anatolian Fault Zone, were analyzed using the Precise Point Positioning (PPP) technique. Computed dynamic displacements shed light to the pattern of dynamic displacements during shallow strike-slip earthquakes. The area of near-field static seismic displacements bounds ramp-type, long-period dynamic displacements (fling steps) in the sense of static displacements. Along-fault and normal to fault components of dynamic displacement follow typical attenuation laws, but attenuation is higher in the fault-parallel component hence confined to the area of static dislocations. Forward directivity and local, especially topography-controlled amplification effects, consistent with accelerometer evidence, were also observed. The overall pattern seems to characterize shallow strike-slip earthquakes and is expected to prove useful to explain or even predict the near-field damaging potential of strike-slip earthquakes.

  4. Striking Pay Dirt!

    ERIC Educational Resources Information Center

    Conger, George

    1984-01-01

    The conception and development of a plan to lease community college property for oil drilling is described, emphasizing the governing board's role in the process. The risks, uncertainties, relationships with local fuel companies, and positive public perception are discussed. (MSE)

  5. Positions of equilibrium points for dust particles in the circular restricted three-body problem with radiation

    NASA Astrophysics Data System (ADS)

    Pástor, P.

    2014-11-01

    For a body with negligible mass moving in the gravitational field of a star with one planet in a circular orbit (the circular restricted three-body problem), five equilibrium points exist and are known as the Lagrangian points. The positions of the Lagrangian points are not valid for dust particles because in the derivation of the Lagrangian points it is assumed that no other forces besides the gravitation act on the body with negligible mass. Here, we determined positions of the equilibrium points for the dust particles in the circular restricted three-body problem with radiation. The equilibrium points are located on curves connecting the Lagrangian points in the circular restricted three-body problem. The equilibrium points for Jupiter are distributed in large interval of heliocentric distances due to its large mass. The equilibrium points for the Earth explain a cloud of dust particles trailing the Earth observed with the Spitzer Space Telescope. The dust particles moving in the equilibrium points are distributed in interplanetary space according to their properties.

  6. Slant Wet Delays from GNSS observations - Precise Point Positioning vs. Double Difference Approach

    NASA Astrophysics Data System (ADS)

    Moeller, Gregor; Weber, Robert

    2015-04-01

    The tropospheric parameter SWD (Slant Wet Delay) is the path delay caused by the highly variable amount of humidity in the atmosphere at altitudes below 12 km. It can be derived from Numerical Weather Predication data or even more precisely from dual- or multi-frequency observations of a regional GNSS reference network. In order to find the most adequate processing strategy dual GNSS observations of a small network of reference stations were simulated and tropospheric parameters were estimated in Precise Point Positioning (PPP) and in Double Difference (DD) mode. In DD mode the integer character of the phase ambiguities remains which allows to fix them to their true values and to obtain the tropospheric zenith delay as well as north and east (N/E) gradients with highest precision over very short time periods. In PPP mode orbit and clock errors are not cancelled out which affects the quality of the tropospheric estimates. On the other hand it has the advantage that the GNSS observations are processed undifferenced. Latter is important because the Zero Difference Residuals (ZDR) contain the azimuthal-anisotropic part of the tropospheric delay which is not covered by the estimated parameters. From Double Difference Residuals (DDR) the ZDR can be recovered too but only conditionally since common tropospheric effects have been cancelled out in advance by differencing. In this presentation we show how good the anisotropic slant path delays can be obtained from GNSS observations processed using both concepts - the PPP and the DD approach. Therefore tropospheric zenith delays and N/E gradients were estimated and Pseudo-ZDR were reconstructed from DDR and afterwards compared with ZDR derived from the PPP solution. In addition it is shown how good both concepts are applicable for observations at very low elevation angles and under extreme weather conditions. The IGS final and ultra-rapid service products were taken into account to define the best strategy not only for post

  7. Performance Analysis of Several GPS/Galileo Precise Point Positioning Models.

    PubMed

    Afifi, Akram; El-Rabbany, Ahmed

    2015-01-01

    This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada's GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference. PMID:26102495

  8. Performance Analysis of Several GPS/Galileo Precise Point Positioning Models

    PubMed Central

    Afifi, Akram; El-Rabbany, Ahmed

    2015-01-01

    This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada’s GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference. PMID:26102495

  9. [COMPLICATIONS RELATED TO PATIENT POSITIONING: KEY POINTS IN PREVENTION AND MANAGEMENT].

    PubMed

    Gal Rinott, Mizrahi; Bat-Chen, Friedman; Boris, Friedman

    2015-11-01

    Patient positioning during surgery can have profound short and long term implications for the patient. Each position carries some degree of risk to the patient, which is magnified in prolonged operations, surgeries performed under general anesthesia and when position manipulations are required in order to gain best surgical access. Prevention is the mainstay of the management of positioning. Therefore, it is crucial that all operating room personnel will be familiar with the different surgical positions and their general and specific position-related injury potential. It is also important that these complications are diagnosed promptly and managed appropriately in the post-operative period. The purpose of the following review is to summarize the positioning-related complications, in particular peripheral nerve injuries, and emphasize correct positioning recommendations and preventive measures. PMID:26821504

  10. Strike the Right Match.

    ERIC Educational Resources Information Center

    Cook, Diana L.; And Others

    1990-01-01

    The University of Akron's department of development designed a screening instrument to help them in the hiring process. The instrument involves: evaluating the job description, writing down the attributes needed, rating the attributes' importance, advertising the position, conducting the interviews, and using the instrument to evaluate the…

  11. The Speech Focus Position Effect on Jaw-Finger Coordination in a Pointing Task

    ERIC Educational Resources Information Center

    Rochet-Capellan, Amelie; Laboissiere, Rafael; Galvan, Arturo; Schwartz, Jean-Luc

    2008-01-01

    Purpose: This article investigates jaw-finger coordination in a task involving pointing to a target while naming it with a 'CVCV (e.g., /'papa/) versus CV'CV (e.g., /pa'pa/) word. According to the authors' working hypothesis, the pointing apex (gesture extremum) would be synchronized with the apex of the jaw-opening gesture corresponding to the…

  12. Triple-frequency GPS precise point positioning with rapid ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Geng, Jianghui; Bock, Yehuda

    2013-05-01

    At present, reliable ambiguity resolution in real-time GPS precise point positioning (PPP) can only be achieved after an initial observation period of a few tens of minutes. In this study, we propose a method where the incoming triple-frequency GPS signals are exploited to enable rapid convergences to ambiguity-fixed solutions in real-time PPP. Specifically, extra-wide-lane ambiguity resolution can be first achieved almost instantaneously with the Melbourne-Wübbena combination observable on L2 and L5. Then the resultant unambiguous extra-wide-lane carrier-phase is combined with the wide-lane carrier-phase on L1 and L2 to form an ionosphere-free observable with a wavelength of about 3.4 m. Although the noise of this observable is around 100 times the raw carrier-phase noise, its wide-lane ambiguity can still be resolved very efficiently, and the resultant ambiguity-fixed observable can assist much better than pseudorange in speeding up succeeding narrow-lane ambiguity resolution. To validate this method, we use an advanced hardware simulator to generate triple-frequency signals and a high-grade receiver to collect 1-Hz data. When the carrier-phase precisions on L1, L2 and L5 are as poor as 1.5, 6.3 and 1.5 mm, respectively, wide-lane ambiguity resolution can still reach a correctness rate of over 99 % within 20 s. As a result, the correctness rate of narrow-lane ambiguity resolution achieves 99 % within 65 s, in contrast to only 64 % within 150 s in dual-frequency PPP. In addition, we also simulate a multipath-contaminated data set and introduce new ambiguities for all satellites every 120 s. We find that when multipath effects are strong, ambiguity-fixed solutions are achieved at 78 % of all epochs in triple-frequency PPP whilst almost no ambiguities are resolved in dual-frequency PPP. Therefore, we demonstrate that triple-frequency PPP has the potential to achieve ambiguity-fixed solutions within a few minutes, or even shorter if raw carrier-phase precisions are

  13. Real Time Precise Point Positioning: Preliminary Results for the Brazilian Region

    NASA Astrophysics Data System (ADS)

    Marques, Haroldo; Monico, João.; Hirokazu Shimabukuro, Milton; Aquino, Marcio

    2010-05-01

    GNSS positioning can be carried out in relative or absolute approach. In the last years, more attention has been driven to the real time precise point positioning (PPP). To achieve centimeter accuracy with this method in real time it is necessary to have available the satellites precise coordinates as well as satellites clocks corrections. The coordinates can be used from the predicted IGU ephemeris, but the satellites clocks must be estimated in a real time. It can be made from a GNSS network as can be seen from EUREF Permanent Network. The infra-structure to realize the PPP in real time is being available in Brazil through the Brazilian Continuous Monitoring Network (RBMC) together with the Sao Paulo State GNSS network which are transmitting GNSS data using NTRIP (Networked Transport of RTCM via Internet Protocol) caster. Based on this information it was proposed a PhD thesis in the Univ. Estadual Paulista (UNESP) aiming to investigate and develop the methodology to estimate the satellites clocks and realize PPP in real time. Then, software is being developed to process GNSS data in the real time PPP mode. A preliminary version of the software was called PPP_RT and is able to process GNSS code and phase data using precise ephemeris and satellites clocks. The PPP processing can be accomplished considering the absolute satellite antenna Phase Center Variation (PCV), Ocean Tide Loading (OTL), Earth Body Tide, among others. The first order ionospheric effects can be eliminated or minimized by ion-free combination or parameterized in the receiver-satellite direction using a stochastic process, e.g. random walk or white noise. In the case of ionosphere estimation, a pseudo-observable is introduced in the mathematical model for each satellite and the initial value can be computed from Klobuchar model or from Global Ionospheric Map (GIM). The adjustment is realized in the recursive mode and the DIA (Detection Identification and Adaptation) is used for quality control. In

  14. Desperate Measures: Strikes and Wages in Post-Accord America

    ERIC Educational Resources Information Center

    Rosenfeld, Jake

    2006-01-01

    Using previously unreleased data on nearly every authorized work stoppage that occurred between 1984 and 2002, this paper tests whether the positive wage-strike relationship held following the breakdown of the post-war labor-capital accord. Unlike in decades past, these findings indicate a complete decoupling of the wage-strike relationship. Even…

  15. Stability characteristics of a supersonic boundary layer and their relation to the position of the laminar-turbulent transition point

    NASA Technical Reports Server (NTRS)

    Lysenko, V. I.

    1987-01-01

    By comparing the calculated results with experimental data, it is demonstrated that the position of the laminar-boundary transition point of a boundary layer can be estimated by using the e-exp-n method. The effect of the Mach number, pressure gradient, and heat transfer on the laminar-turbulent transition is discussed. It is found that under conditions of strong cooling, the effect of the pressure gradient on the position of the transition point is less pronounced than in the absence of heat transfer.

  16. Positive Thinking & Good Citizenship Culture: From the Jordanian Universities Students' Points of View

    ERIC Educational Resources Information Center

    Jarrar, Amani Ghazi

    2013-01-01

    This study aims at identifying the nature of the relationship between the mode of thinking among the students of Jordanian Universities if positive, and the extent to which that is related to their culture of citizenship, and therefore their positive practices towards the community. A sample of (654) students were selected randomly. And to achieve…

  17. Evaluation of Point Positioning Using the Global Positioning System and the Quasi-Zenith Satellite System as Measured from South Korea

    NASA Astrophysics Data System (ADS)

    Choi, Byung-Kyu; Cho, Chang-Hyun; Cho, Jung Ho

    2015-12-01

    The Quasi-Zenith Satellite System (QZSS), a dedicated regional Japanese satellite system currently under development, was designed to complement the performance of the Global Positioning System (GPS). The high elevation angle of the QZSS satellite is expected to enhance the effectiveness of GPS in urban environments. Thus, the work described in this paper, aimed to investigate the effect of QZSS on GPS performance, by processing the GPS and QZSS measurements recorded at the Bohyunsan reference station in South Korea. We used these data, to evaluate the satellite visibility, carrier-to-noise density (C/No), performance of single point positioning, and Dilution of Precision (DOP). The QZSS satellite is currently available over South Korea for 19 hours at an elevation angle of more than 10 degrees. The results showed that the impact of the QZSS on users' vertical positioning is greatest when the satellite is above 80 degrees of elevation. As for Precise Point Positioning (PPP) performance, the combined GPS/QZSS kinematic PPP was found to improve the positioning accuracy compared to the GPS only kinematic PPP.

  18. Positioning.

    ERIC Educational Resources Information Center

    Conone, Ruth M.

    The key to positioning is the creation of a clear benefit image in the consumer's mind. One positioning strategy is creating in the prospect's mind a position that takes into consideration the company's or agency's strengths and weaknesses as well as those of its competitors. Another strategy is to gain entry into a position ladder owned by…

  19. Modern Protection Against Lightning Strikes

    NASA Astrophysics Data System (ADS)

    Moore, C.

    2005-05-01

    The application of science to provide protection against lightning strikes began around 1750 when Benjamin Franklin who invented the lightning rod in an effort to discharge thunderclouds. Instead of preventing lightning as he expected, his rods have been quite successful as strike receptors, intercepting cloud-to ground discharges and conducting them to Earth without damage to the structures on which they are mounted. In the years since Franklin's invention there has been little attention paid to the rod configuration that best serves as a strike receptor but Franklin's original ideas continue to be rediscovered and promoted. Recent measurements of the responses of variously configured rods to nearby strikes indicate that sharp-tipped rods are not the optimum configuration to serve as strike receptors since the ionization of the air around their tips limits the strength of the local electric fields created by an approaching lightning leader. In these experiments, fourteen blunt-tipped rods exposed in strike-reception competitions with nearby sharp-tipped rods were struck by lightning but none of the sharp-tipped rods were struck.

  20. Physicians' changing attitudes about striking.

    PubMed

    Wassertheil-Smoller, S; Croen, L; Siegel, B

    1979-01-01

    Both interns and residents and practicing physicians express substantial support for physicians' organizing for collective bargaining and striking. These findings, from 1146 respondents to a 1976 survey of the alumni of the Albert Einstein College of Medicine, indicate that profound changes have occurred in physicians' views on these issues. Although the greatest support for striking came from interns and residents, with 67 per cent of them indicating they think physicians should be allowed to strike, the survey found an increasing pattern of militancy commencing with 1964 graduates. Physicians in private practice and those who spent two-thirds or more of their time in direct patient care were the most likely to support strikes by physicians (60 per cent), while the least support came from those fulltime on medical school faculties (39 per cent). No differences in support for striking were found in relation to sex, religion or size of community in which physicians practice. A longitudinal examination of the medical school Class of 1975 at matriculation, at graduation and during internship training reveals that a major growth of support for striking occurred between matriculation and graduation. PMID:759745

  1. Precise angular position measurement of a point source in an optoelectronic system with CCD arrays upon a single readout

    NASA Astrophysics Data System (ADS)

    Lebedko, Evgeny G.; Zvereva, Elena N.

    2015-05-01

    The purpose of this article is to examine the method of angular position measuring of a point source in a system with a CCD array by means of linear dimension - time slot - code transformation and assessment of the potential accuracy of the method, which is determined by instrumental irremovable random errors of measurement in terms of optimal processing of incoming information with a single reading it with CCD - lines. This work introduces an optoelectronic system circuit with CCD arrays with stretched sensing elements and a point of reference for angular position measuring. In this case the arrays have images projections of both the reference point source and the target point source, whose angular position is measured with high precision. From the CCD array output the signals arrive at an optimal (or apt) linear filter, and then to the signal peak position detection circuit, which provides the minimum error due to noise impact. Pulse edges, corresponding to the signals maximum, make a time interval filled with high-frequency counting pulses. The number of pulses in this interval will correspond to the measured angular position of the target point source. In terms of the statistical decision theory this work analyses random errors given the signals spectral function that, in turn, accounts for the transfer function of the optical system and the CCD array as an image analyzer. This article also presents analysis of how measurement accuracy depends on frequency of information readout from the CCD-arrays for different values of signal-to-noise ratio. Error analysis of the proposed optoelectronic circuits showed that measurements can be made upon a single readout with an accuracy of 0.01 and even 0,001 pixels.

  2. Pointing the profession in the right direction: positive ethical movements among dental students and education.

    PubMed

    Loftis, Brooke

    2008-01-01

    The American Student Dental Association has a substantial stake in the future of the dental profession. ASDA is taking a proactive role in addressing recently publicized cases of academic dishonesty and other ethical problems. Some of these initiatives and a sampling of the positive efforts in dental schools to build sound ethical climates are reviewed. PMID:18777888

  3. An Efficient Real-Time Precise Point Positioning (RT-PPP) Solution for Offshore Surveys in Turkey

    NASA Astrophysics Data System (ADS)

    Abdelazeem, Mohamed; Nurhan Çelik, Rahmi

    2016-07-01

    Recently, the international global navigation satellite systems (GNSS) service (IGS) has launched the real-time service (IGS-RTS). The IGS-RTS has shown promise accuracy in precise point positioning applications. Currently, the precise point positioning technique is used extensively in marine applications. In this study, we evaluate the accuracy of the real-time precise point positioning (RT-PPP) solution using the IGS-RTS for offshore surveys in Turkey. Dual-frequency GPS data is collected onboard a vessel and then processed using the Bernese 5.2 PPP module. The IGS-RTS precise orbit and clock products are used in order to account for the satellite orbit and clock products. To investigate the accuracy of the RT-PPP technique, the positioning accuracy is assessed and compared with the traditional double-difference solution. It is shown that the RT-PPP solution has good agreement with the double-difference solution. Also, the proposed solution efficiently fulfills the international maritime organization (IMO) standards for the offshore surveys.

  4. EMAS position statement: The ten point guide to the integral management of menopausal health.

    PubMed

    Neves-E-Castro, Manuel; Birkhauser, Martin; Samsioe, Goran; Lambrinoudaki, Irene; Palacios, Santiago; Borrego, Rafael Sanchez; Llaneza, Placido; Ceausu, Iuliana; Depypere, Herman; Erel, C Tamer; Pérez-López, Faustino R; Schenck-Gustafsson, Karin; van der Schouw, Yvonne T; Simoncini, Tommaso; Tremollieres, Florence; Rees, Margaret

    2015-05-01

    With increased longevity and more women becoming centenarians, management of the menopause and postreproductive health is of growing importance as it has the potential to help promote health over several decades. Women have individual needs and the approach needs to be personalised. The position statement provides a short integral guide for all those involved in menopausal health. It covers diagnosis, screening for diseases in later life, treatment and follow-up. PMID:25757366

  5. Influence of meteorological data and horizontal gradient of tropospheric model on precise point positioning

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Jiang, Nan; Xu, Guochang; Yang, Yuanxi; Schuh, Harald

    2015-12-01

    Using GPT2 derived meteorological data and actual meteorological observations can achieve the same positioning precision in the most areas worldwide except for the Antarctic region. However, the improvement of the actual meteorological observations on the positioning result is significant comparing to using GPT2 derived meteorological data in Antarctic. In the case of 5° elevation cut-off angle, the height precision can be improved by 25%. Furthermore, when the elevation cut-off angle is lower, the effect of the actual meteorological observations on the positioning precision is more significant in Antarctic due to the retention of low elevation angle observations. This study also shows that the influence of tropospheric horizontal gradient correction can improve the PPP precision. Under the lower elevation cut-off angle and higher humidity conditions, especially in summer time and low-latitudes area, the usefulness of the horizontal gradient correction is remarkable. The average improvement of N, E and U directions can reach up to 51%, 15% and 30%, respectively.

  6. First strike: myth or reality

    SciTech Connect

    Anderson, J.E.

    1981-11-01

    Before accepting the military establishment's belief that alleged Soviet first-strike capability makes the MX program urgent, it is worthwhile to examine both the evidence and the conclusion. Using unclassified information, the author examines the arguments in terms of what kind of attack the Soviets might make, how the attack will affect the Soviet Union, missile testing, the real-kill probability, the miss probability, and the perception of a threat and sees little justification for confidence in the results of a first strike. He feels, however, that administration beliefs will be based on intuition and ideology rather than technical assessment. That, coupled with the acknowledged first-strike capability of the US, increases the danger. 12 references. (DCK)

  7. [Physicians' strikes--ethical considerations].

    PubMed

    Glick, Shimon; Schwarzfuchs, Dan

    2012-01-01

    Strikes in general represent a solution based on a form of coercion. Historically, the striker caused direct damage to his employer, who was responsible for the perceived unfair treatment of the employee. In the case of strikes in the public sector, the employer is generally not harmed, but innocent citizens suffer in order to pressure the government agencies, a questionable practice from an ethical viewpoint. Physicians' strikes have more serious ethical problems. They cause suffering and death to innocent citizens. They violate the ethical codes to which physicians have committed themselves as professionals, and they seriously impair the trust of the public in physicians. Better and more ethical ways to provide fair compensation for physicians must be employed, perhaps like those used for judges and members of the IDF. PMID:22670493

  8. Crustal deformation measurements in central Japan determined by a Global Positioning System fixed-point network

    NASA Technical Reports Server (NTRS)

    Shimada, Seiichi; Bock, Yehuda

    1992-01-01

    Results are presented from temporally dense measurements of crustal deformation associated with the convergence of the Eurasian (EUR), Pacific, North American, and Philippine Sea (PHS) plates, carried out in April 1988 by a 10-station GPS fixed-point network established in central Japan. Using regional orbit relaxation methods, the analysis of the first 17-month data revealed significant horizontal deformation across the Suruga trough. Namely, it was found that a site in the northern tip of PHS plate moved nearly westward with a velocity of 28 +/-5 mm per year, and a site at the southeastern tip of EUR plate moved south-southwestward with a velocity of 18 +/-5 mm per year. A significant vertical uplift with a velocity of 20 mm/yr was detected at a site inland of the Tokai district located in the Akaishi uplift zone and at a site on the Hatsushima Island in Sagami Bay.

  9. Real-Time Point Positioning Performance Evaluation of Single-Frequency Receivers Using NASA's Global Differential GPS System

    NASA Technical Reports Server (NTRS)

    Muellerschoen, Ronald J.; Iijima, Byron; Meyer, Robert; Bar-Sever, Yoaz; Accad, Elie

    2004-01-01

    This paper evaluates the performance of a single-frequency receiver using the 1-Hz differential corrections as provided by NASA's global differential GPS system. While the dual-frequency user has the ability to eliminate the ionosphere error by taking a linear combination of observables, the single-frequency user must remove or calibrate this error by other means. To remove the ionosphere error we take advantage of the fact that the magnitude of the group delay in range observable and the carrier phase advance have the same magnitude but are opposite in sign. A way to calibrate this error is to use a real-time database of grid points computed by JPL's RTI (Real-Time Ionosphere) software. In both cases we evaluate the positional accuracy of a kinematic carrier phase based point positioning method on a global extent.

  10. X-ray position detector and implementation in a mirror pointing servo system

    DOEpatents

    Rabedeau, Thomas A.; Van Campen, Douglas G.; Stefan, Peter M.

    2016-04-05

    An X-ray beam position and stability detector is provided having a first metal blade collinear with a second metal blade, where an edge of the first metal blade is opposite an edge of the second metal blade, where the first metal blade edge and the second metal blade edge are disposed along a centerline with respect to each other, where the metal blades are capable of photoelectron emission when exposed to an x-ray beam, a metal coating on the metal blades that is capable of enhancing the photoelectron emission, or suppressing energy-resonant contaminants, or enhancing the photoelectron emission and suppressing energy-resonant contaminants, a background shielding element having an electrode capable of suppressing photoelectron emission from spurious x-rays not contained in an x-ray beam of interest, and a photoelectron emission detector having an amplifier capable of detecting the photoelectron emission as a current signal.

  11. Three point lead screw positioning apparatus for a cavity tuning plate

    NASA Technical Reports Server (NTRS)

    Calco, Frank S. (Inventor)

    1993-01-01

    Three lead screws are provided for adjusting the position of a traversing plate. Each of the three lead screws is threaded through a collar that is press fitted through the center of one of three pinion gears. A sun gear meshes with all three pinion gears and transversely moves the three lead screws upon actuation of a drive gear. The drive gear meshes with the sun gear and is driven by a handle or servomotor. When the handle or servomotor rotates the drive gear, the sun gear rotates causing the three pinion gears to rotate, thus, causing transverse movement of the three lead screws and, accordingly, transverse movement of the transversing plate. When the drive gear rotates, the traversing plate is driven in and out of a microwave cavity. Thus, the length or size of the cavity can be tuned while maintaining the traversing plate in an exact parallel relationship with an opposing plate on another end of the cavity.

  12. The effect of the sulfur position on the melting points of lipidic 1-methyl-3-thiaalkylimidazolium ionic liquids.

    PubMed

    O'Brien, Richard A; Mirjafari, Arsalan; Mattson, Kaila M; Murray, Samuel M; Mobarrez, Niloufar; Salter, E Alan; Wierzbicki, Andrzej; Davis, James H; West, Kevin N

    2014-08-28

    A series of novel lipid-inspired ionic liquids have been synthesized employing the thiol-ene "click" reaction in a single-step process. The thermal properties were determined by differential scanning calorimetry (DSC) and showed observable trends between the C16, C18, and C20 analogues. The minimum melting points for each equivalent chain length series occur at sequential odd sulfur positions, 3, 5, and 7 for the C16, C18, and C20 series, respectively. The magnitude of melting point depression relative to the saturated homologue is observed to have a strong dependence on the position of the sulfur in the side chain. Additionally, the sulfur position corresponding to the lowest melting point for a homologous series shifts further down the chain as the chain length is increased, indicating that the maximum effect takes place near the center of the ion and not the center of the thiaalkyl chain. This synthesis provides tunability and improved thermal stability for 1-methyl-3-thiaalkylimidazolium bistriflimides and insight into structure-property relationships of lipidic ionic liquids. PMID:25134012

  13. Accuracy Assessment of the Precise Point Positioning for Different Troposphere Models

    NASA Astrophysics Data System (ADS)

    Oguz Selbesoglu, Mahmut; Gurturk, Mert; Soycan, Metin

    2016-04-01

    This study investigates the accuracy and repeatability of PPP technique at different latitudes by using different troposphere delay models. Nine IGS stations were selected between 00-800 latitudes at northern hemisphere and southern hemisphere. Coordinates were obtained for 7 days at 1 hour intervals in summer and winter. At first, the coordinates were estimated by using Niell troposphere delay model with and without including north and east gradients in order to investigate the contribution of troposphere delay gradients to the positioning . Secondly, Saastamoinen model was used to eliminate troposphere path delays by using standart atmosphere parameters were extrapolated for all station levels. Finally, coordinates were estimated by using RTCA-MOPS empirical troposphere delay model. Results demonstrate that Niell troposphere delay model with horizontal gradients has better mean values of rms errors 0.09 % and 65 % than the Niell troposphere model without horizontal gradients and RTCA-MOPS model, respectively. Saastamoinen model mean values of rms errors were obtained approximately 4 times bigger than the Niell troposphere delay model with horizontal gradients.

  14. Modeling and assessment of triple-frequency BDS precise point positioning

    NASA Astrophysics Data System (ADS)

    Guo, Fei; Zhang, Xiaohong; Wang, Jinling; Ren, Xiaodong

    2016-06-01

    The latest generation of GNSS satellites such as GPS BLOCK-IIF, Galileo and BDS are transmitting signals on three or more frequencies, thus having more choices in practice. At the same time, new challenges arise for integrating the new signals. This paper contributes to the modeling and assessment of triple-frequency PPP with BDS data. First, three triple-frequency PPP models are developed. The observation model and stochastic model are designed and extended to accommodate the third frequency. In particular, new biases such as differential code biases and inter-frequency biases as well as the parameterizations are addressed. Then, the relationships between different PPP models are discussed. To verify the triple-frequency PPP models, PPP tests with real triple-frequency data were performed in both static and kinematic scenarios. Results show that the three triple-frequency PPP models agree well with each other. Additional frequency has a marginal effect on the positioning accuracy in static PPP tests. However, the benefits of third frequency are significant in situations of where there is poor tracking and contaminated observations on frequencies B1 and B2 in kinematic PPP tests.

  15. Soviet KIROV class strike cruiser

    SciTech Connect

    Kehoe, J.W.; Brower, K.S.; Meier, H.A.

    1981-04-01

    The major design concepts and basic characteristics of the Soviet KIROV Class ship, an impressive nuclear-powered Strike Cruiser which recently appeared while undergoing sea trials in the Baltic Sea and the North Sea, are discussed. Highlights are presented of the KIROV's hull form, the weapons, electronics and aviation systems, machinery, as well as the cruiser's speed and range.

  16. Communicating During Negotiations/Strikes.

    ERIC Educational Resources Information Center

    National School Public Relations Association, Arlington, VA.

    Successful collective bargaining and, if necessary, strike management, requires careful planned communication strategies and programs before, during, and after, if the school system is to maintain the public's confidence. This handbook is designed to provide guidelines for the educational administrative team in developing a communication plan that…

  17. Exchange energy gradients with respect to atomic positions and cell parameters within the Hartree-Fock Gamma-point approximation.

    PubMed

    Weber, Valéry; Daul, Claude; Challacombe, Matt

    2006-06-01

    Recently, linear scaling construction of the periodic exact Hartree-Fock exchange matrix within the Gamma-point approximation has been introduced [J. Chem. Phys. 122, 124105 (2005)]. In this article, a formalism for evaluation of analytical Hartree-Fock exchange energy gradients with respect to atomic positions and cell parameters at the Gamma-point approximation is presented. While the evaluation of exchange gradients with respect to atomic positions is similar to those in the gas phase limit, the gradients with respect to cell parameters involve the accumulation of atomic gradients multiplied by appropriate factors and a modified electron repulsion integral (ERI). This latter integral arises from use of the minimum image convention in the definition of the Gamma-point Hartree-Fock approximation. We demonstrate how this new ERI can be computed with the help of a modified vertical recurrence relation in the frame of the Obara-Saika and Head-Gordon-Pople algorithm. As an illustration, the analytical gradients have been used in conjunction with the QUICCA algorithm [K. Nemeth and M. Challacombe, J. Chem. Phys. 121, 2877 (2004)] to optimize periodic systems at the Hartree-Fock level of theory. PMID:16774396

  18. Exchange energy gradients with respect to atomic positions and cell parameters within the Hartree-Fock Γ-point approximation

    NASA Astrophysics Data System (ADS)

    Weber, Valéry; Daul, Claude; Challacombe, Matt

    2006-06-01

    Recently, linear scaling construction of the periodic exact Hartree-Fock exchange matrix within the Γ-point approximation has been introduced [J. Chem. Phys. 122, 124105 (2005)]. In this article, a formalism for evaluation of analytical Hartree-Fock exchange energy gradients with respect to atomic positions and cell parameters at the Γ-point approximation is presented. While the evaluation of exchange gradients with respect to atomic positions is similar to those in the gas phase limit, the gradients with respect to cell parameters involve the accumulation of atomic gradients multiplied by appropriate factors and a modified electron repulsion integral (ERI). This latter integral arises from use of the minimum image convention in the definition of the Γ-point Hartree-Fock approximation. We demonstrate how this new ERI can be computed with the help of a modified vertical recurrence relation in the frame of the Obara-Saika and Head-Gordon-Pople algorithm. As an illustration, the analytical gradients have been used in conjunction with the QUICCA algorithm [K. Németh and M. Challacombe, J. Chem. Phys. 121, 2877 (2004)] to optimize periodic systems at the Hartree-Fock level of theory.

  19. The Teachers' Strike Study. Sudbury, Ontario, 1980.

    ERIC Educational Resources Information Center

    Radecki, Henry; Evans, Susan

    Focusing on the 1980 strike of public secondary school teachers in Sudbury, Ontario, this study examined attitudes of those involved; ascertained feelings toward the school system that may have emerged since the strike; and examined events, influences, and developments leading to the strike and prolonging the strike. The field study represented…

  20. Follow-up Survey of Strike Impact.

    ERIC Educational Resources Information Center

    Grayson, J. Paul

    During a faculty strike at York University (Ontario), two telephone surveys were undertaken to assess student perceptions of the strike. The first survey was taken during the fifth and sixth weeks of the strike, with the objective of documenting the experiences of students while the strike was on. The questionnaire for this survey was developed…

  1. Joint positioning sense, perceived force level and two-point discrimination tests of young and active elderly adults

    PubMed Central

    Franco, Priscila G.; Santos, Karini B.; Rodacki, André L. F.

    2015-01-01

    Background: Changes in the proprioceptive system are associated with aging. Proprioception is important to maintaining and/or recovering balance and to reducing the risk of falls. Objective: To compare the performance of young and active elderly adults in three proprioceptive tests. Method: Twenty-one active elderly participants (66.9±5.5 years) and 21 healthy young participants (24.6±3.9 years) were evaluated in the following tests: perception of position of the ankle and hip joints, perceived force level of the ankle joint, and two-point discrimination of the sole of the foot. Results: No differences (p>0.05) were found between groups for the joint position and perceived force level. On the other hand, the elderly participants showed lower sensitivity in the two-point discrimination (higher threshold) when compared to the young participants (p < 0.01). Conclusion: Except for the cutaneous plantar sensitivity, the active elderly participants had maintained proprioception. Their physical activity status may explain similarities between groups for the joint position sense and perceived force level, however it may not be sufficient to prevent sensory degeneration with aging. PMID:26443978

  2. Position difference regularity of corresponding R-wave peaks for maternal ECG components from different abdominal points

    NASA Astrophysics Data System (ADS)

    Zhang, Jie-Min; Guan, Qun; Tang, Li-Ming; Liu, Tie-Bing; Liu, Hong-Xing; Huang, Xiao-Lin; Si, Jun-Feng

    2014-01-01

    We collected 343 groups of abdominal electrocardiogram (ECG) data from 78 pregnant women and deleted the channels unable for experts to determine R-wave peaks from them; then, based on these filtered data, the statistics of position difference of corresponding R-wave peaks for different maternal ECG components from different points were studied. The resultant statistics showed the regularity that the position difference of corresponding maternal R-wave peaks between different abdominal points does not exceed the range of 30 ms. The regularity was also proved using the fECG data from MIT—BIH PhysioBank. Additionally, the paper applied the obtained regularity, the range of position differences of the corresponding maternal R-wave peaks, to accomplish the automatic detection of maternal R-wave peaks in the recorded all initial 343 groups of abdominal signals, including the ones with the largest fetal ECG components, and all 55 groups of ECG data from MIT—BIH PhysioBank, achieving the successful separation of the maternal ECGs.

  3. Takotsubo cardiomyopathy following lightning strike.

    PubMed

    Dundon, B K; Puri, R; Leong, D P; Worthley, M I

    2008-07-01

    Lightning strike is the most common environmental cause of sudden cardiac death, but may also be associated with a myriad of injuries to various organ systems. Direct myocardial injury may be manifest as electrocardiographic alterations or elevation in cardiac-specific isoenzymes; however, significant electrical cardiac trauma appears uncommon. A case is presented of severe acute cardiomyopathy in a "Takotsubo" distribution causing cardiogenic shock following lightning strike in a previously healthy 37-year-old woman. Although rarely identified in this context, Takotsubo cardiomyopathy (also known as "transient left ventricular apical ballooning syndrome") is characterised by transient cardiac dysfunction, electrocardiographic changes that may mimic acute myocardial infarction and minimal release of cardiac-specific enzymes in the absence of obstructive coronary artery disease. The condition is associated with a substantial female bias (up to 90% of cases) in reported series, and despite occasionally dramatic presentations recovery of left ventricular function is almost universal over days to weeks. In rare instances, however, the syndrome has been associated with more catastrophic complications such as papillary muscle or cardiac free wall rupture, necessitating emergency surgical intervention to preserve life. In clinical practice, non-lethal lightning strike-induced cardiac injury is frequently associated with small elevations of cardiac isoenzymes without overt clinical sequelae; however, the incidence of silent myocardial mechanical dysfunction remains unknown. Cases such as the one presented highlight the potential for serious, albeit usually transient, cardiac sequelae from lightning strike injury and remind us that our mothers' advice to remain indoors during thunderstorms is probably worth heeding. PMID:18573973

  4. Takotsubo cardiomyopathy following lightning strike.

    PubMed

    Dundon, Benjamin K; Puri, Rishi; Leong, Darryl P; Worthley, Matthew Ian

    2009-01-01

    Lightning strike is the most common environmental cause of sudden cardiac death, but it may also be associated with a myriad of injuries to various organ systems. Direct myocardial injury may be manifest as electrocardiographic alterations or elevation in cardiac-specific isoenzymes; however, significant electrical cardiac trauma appears uncommon. A case is presented of severe acute cardiomyopathy in a "Takotsubo" distribution causing cardiogenic shock following lightning strike in a previously healthy 37-year-old woman. Although rarely identified in this context, Takotsubo cardiomyopathy (also known as "transient left ventricular apical ballooning syndrome") is characterised by transient cardiac dysfunction, electrocardiographic changes that may mimic acute myocardial infarction and minimal release of cardiac-specific enzymes in the absence of obstructive coronary artery disease. The condition is associated with a substantial female bias (up to 90% of cases) in reported series, and despite occasionally dramatic presentations recovery of left ventricular function is almost universal over days to weeks. In rare instances, however, the syndrome has been associated with more catastrophic complications such as papillary muscle or cardiac free wall rupture, necessitating emergency surgical intervention to preserve life. In clinical practice, non-lethal lightning strike-induced cardiac injury is frequently associated with small elevations of cardiac isoenzymes without overt clinical sequelae; however, the incidence of silent myocardial mechanical dysfunction remains unknown. Cases such as the one presented highlight the potential for serious, albeit usually transient, cardiac sequelae from lightning strike injury and remind us that our mothers' advice to remain indoors during thunderstorms is probably worth heeding. PMID:21686980

  5. Real-time GPS sensing of atmospheric water vapor: Precise point positioning with orbit, clock, and phase delay corrections

    NASA Astrophysics Data System (ADS)

    Li, Xingxing; Dick, Galina; Ge, Maorong; Heise, Stefan; Wickert, Jens; Bender, Michael

    2014-05-01

    The recent development of the International Global Navigation Satellite Systems Service Real-Time Pilot Project and the enormous progress in precise point positioning (PPP) techniques provide a promising opportunity for real-time determination of Integrated Water Vapor (IWV) using GPS ground networks for various geodetic and meteorological applications. In this study, we develop a new real-time GPS water vapor processing system based on the PPP ambiguity fixing technique with real-time satellite orbit, clock, and phase delay corrections. We demonstrate the performance of the new real-time water vapor estimates using the currently operationally used near-real-time GPS atmospheric data and collocated microwave radiometer measurements as an independent reference. The results show that an accuracy of 1.0 ~ 2.0 mm is achievable for the new real-time GPS based IWV value. Data of such accuracy might be highly valuable for time-critical geodetic (positioning) and meteorological applications.

  6. On the convergence of ionospheric constrained precise point positioning (IC-PPP) based on undifferential uncombined raw GNSS observations.

    PubMed

    Zhang, Hongping; Gao, Zhouzheng; Ge, Maorong; Niu, Xiaoji; Huang, Ling; Tu, Rui; Li, Xingxing

    2013-01-01

    Precise Point Positioning (PPP) has become a very hot topic in GNSS research and applications. However, it usually takes about several tens of minutes in order to obtain positions with better than 10 cm accuracy. This prevents PPP from being widely used in real-time kinematic positioning services, therefore, a large effort has been made to tackle the convergence problem. One of the recent approaches is the ionospheric delay constrained precise point positioning (IC-PPP) that uses the spatial and temporal characteristics of ionospheric delays and also delays from an a priori model. In this paper, the impact of the quality of ionospheric models on the convergence of IC-PPP is evaluated using the IGS global ionospheric map (GIM) updated every two hours and a regional satellite-specific correction model. Furthermore, the effect of the receiver differential code bias (DCB) is investigated by comparing the convergence time for IC-PPP with and without estimation of the DCB parameter. From the result of processing a large amount of data, on the one hand, the quality of the a priori ionosphere delays plays a very important role in IC-PPP convergence. Generally, regional dense GNSS networks can provide more precise ionosphere delays than GIM and can consequently reduce the convergence time. On the other hand, ignoring the receiver DCB may considerably extend its convergence, and the larger the DCB, the longer the convergence time. Estimating receiver DCB in IC-PPP is a proper way to overcome this problem. Therefore, current IC-PPP should be enhanced by estimating receiver DCB and employing regional satellite-specific ionospheric correction models in order to speed up its convergence for more practical applications. PMID:24253190

  7. On the Convergence of Ionospheric Constrained Precise Point Positioning (IC-PPP) Based on Undifferential Uncombined Raw GNSS Observations

    PubMed Central

    Zhang, Hongping; Gao, Zhouzheng; Ge, Maorong; Niu, Xiaoji; Huang, Ling; Tu, Rui; Li, Xingxing

    2013-01-01

    Precise Point Positioning (PPP) has become a very hot topic in GNSS research and applications. However, it usually takes about several tens of minutes in order to obtain positions with better than 10 cm accuracy. This prevents PPP from being widely used in real-time kinematic positioning services, therefore, a large effort has been made to tackle the convergence problem. One of the recent approaches is the ionospheric delay constrained precise point positioning (IC-PPP) that uses the spatial and temporal characteristics of ionospheric delays and also delays from an a priori model. In this paper, the impact of the quality of ionospheric models on the convergence of IC-PPP is evaluated using the IGS global ionospheric map (GIM) updated every two hours and a regional satellite-specific correction model. Furthermore, the effect of the receiver differential code bias (DCB) is investigated by comparing the convergence time for IC-PPP with and without estimation of the DCB parameter. From the result of processing a large amount of data, on the one hand, the quality of the a priori ionosphere delays plays a very important role in IC-PPP convergence. Generally, regional dense GNSS networks can provide more precise ionosphere delays than GIM and can consequently reduce the convergence time. On the other hand, ignoring the receiver DCB may considerably extend its convergence, and the larger the DCB, the longer the convergence time. Estimating receiver DCB in IC-PPP is a proper way to overcome this problem. Therefore, current IC-PPP should be enhanced by estimating receiver DCB and employing regional satellite-specific ionospheric correction models in order to speed up its convergence for more practical applications. PMID:24253190

  8. [Force-feeding of hunger-striking prisoners].

    PubMed

    Glick, Shimon

    2014-09-01

    In contrast to the position of the World Medical Association and the Ethics Council of the Israel Medical Association, the author argues for forced-feeding of hunger-striking prisoners when their condition reaches a stage of danger of death or permanent injury. This position is based on the priority of human life over autonomy, and of a communitarian ethic. This position is supported by a District Court decision ordering the feeding of a hunger-striking prisoner, by a Supreme Court decision imposing surgery on a non-consenting prisoner, and in line with Israel's Patient's Right Law. PMID:25417495

  9. Angular selection of incident waves by photonic crystals with position-varying Dirac points at the Brillouin zone boundary

    NASA Astrophysics Data System (ADS)

    Xu, Changqing; Fang, Anan; Chu, Hongchen; Luo, Jie; Chan, C. T.; Hang, Zhi Hong; Lai, Yun

    2016-06-01

    We demonstrate the angular selection of incident electromagnetic waves using photonic crystals (PCs) composed of a square lattice of dielectric rods which exhibit position-varying Dirac conical dispersion at the Brillouin zone boundary. At the frequency of the Dirac point, the transmittance can reach unity at a particular incident angle associated with the Dirac dispersion, while for all other incident angles the waves are reflected due to the existence of a directional photonic band gap. By changing the size of the dielectric rods, the position of the Dirac point at the Brillouin zone boundary is variable, which makes the unity transmission angle customizable. Interestingly, we show that such a scheme of angular selection is almost independent of the refractive index of the background medium, as long as it is not too large so that a diffraction effect emerges. By investigating the PC being sandwiched by two different types of media, we find it actually acts as an optical 0 or π phase modulator at that particular incident angle. By attaching a metasurface to the PC, angular selection in the reflection geometry can also be achieved. Our work establishes a systematic and efficient method to achieve angular selection of arbitrary incident waves based on Dirac dispersions.

  10. Three dimensional indoor positioning based on visible light with Gaussian mixture sigma-point particle filter technique

    NASA Astrophysics Data System (ADS)

    Gu, Wenjun; Zhang, Weizhi; Wang, Jin; Amini Kashani, M. R.; Kavehrad, Mohsen

    2015-01-01

    Over the past decade, location based services (LBS) have found their wide applications in indoor environments, such as large shopping malls, hospitals, warehouses, airports, etc. Current technologies provide wide choices of available solutions, which include Radio-frequency identification (RFID), Ultra wideband (UWB), wireless local area network (WLAN) and Bluetooth. With the rapid development of light-emitting-diodes (LED) technology, visible light communications (VLC) also bring a practical approach to LBS. As visible light has a better immunity against multipath effect than radio waves, higher positioning accuracy is achieved. LEDs are utilized both for illumination and positioning purpose to realize relatively lower infrastructure cost. In this paper, an indoor positioning system using VLC is proposed, with LEDs as transmitters and photo diodes as receivers. The algorithm for estimation is based on received-signalstrength (RSS) information collected from photo diodes and trilateration technique. By appropriately making use of the characteristics of receiver movements and the property of trilateration, estimation on three-dimensional (3-D) coordinates is attained. Filtering technique is applied to enable tracking capability of the algorithm, and a higher accuracy is reached compare to raw estimates. Gaussian mixture Sigma-point particle filter (GM-SPPF) is proposed for this 3-D system, which introduces the notion of Gaussian Mixture Model (GMM). The number of particles in the filter is reduced by approximating the probability distribution with Gaussian components.

  11. Principal Component Analysis of the Time- and Position-dependent Point-Spread Function of the Advanced Camera for Surveys

    NASA Astrophysics Data System (ADS)

    Jee, M. J.; Blakeslee, J. P.; Sirianni, M.; Martel, A. R.; White, R. L.; Ford, H. C.

    2007-12-01

    We describe the time- and position-dependent point-spread function (PSF) variation of the wide-field channel (WFC) of the Advanced Camera for Surveys (ACS) with the principal component analysis (PCA) technique. The time-dependent change is caused by the temporal variation of the HST focus, whereas the position-dependent PSF variation in ACS WFC at a given focus is mainly the result of changes in aberrations and charge diffusion across the detector, which appear as position-dependent changes in the elongation of the astigmatic core and blurring of the PSF, respectively. Using ˜ 20 ) of principal components or "eigen-PSFs" per exposure can robustly reproduce the observed variation of the ellipticity and size of the PSF. Our primary interest in this investigation is the application of this PSF library to precision weak-lensing analyses, where accurate knowledge of the instrument's PSF is crucial. However, the high fidelity of the model judged from the nice agreement with observed PSFs suggests that the model is potentially also useful in other applications, such as crowded field stellar photometry, galaxy profile fitting, AGN studies, etc., which similarly demand a fair knowledge of the PSFs at objects' locations. Our PSF models, applicable to any WFC image rectified with the Lanczos3 kernel, are publicly available.

  12. Precise point positioning performance in the presence of the 28 October 2003 sudden increase in total electron content

    NASA Astrophysics Data System (ADS)

    Rodríguez-Bilbao, I.; Radicella, S. M.; Rodríguez-Caderot, G.; Herraiz, M.

    2015-10-01

    Intense disturbances in the ionosphere may produce perturbations in Global Navigation Satellite Systems (GNSS) radio signals that in the most severe cases produce receiver tracking problems, which in turn impact on GNSS positioning accuracy. In this paper we present a case study related to the sudden increase in total electron content (SITEC) induced by the X17.2 solar flare that occurred on 28 October 2003. This is the largest SITEC ever recorded by means of the rate of change of total electron content. A solar radio burst (SRB) occurred in the same period which caused GNSS signal fading and in some cases complete signal loss. Although SITEC contribution to the signal noise cannot be separated from that of SRB, in this paper we show that accuracy degradation may happen in kinematic precise point positioning (PPP) in several stations of the sunlit hemisphere when 30 s sampling rate data are analyzed. The observed errors in the position are the result of the difficulties that cycle slip (CS) detection strategies have to deal with the observables that have been affected by the SITEC.

  13. Lightning strike at Bryan, Ohio

    SciTech Connect

    Nichols, B. E.

    1980-02-01

    A week before the 29 August 1979 dedication of the photovoltaic power system at daytime AM radio station WBNO, in Bryan, Ohio, a lightning superbolt struck the FM radio tower, one of two towers at the station. Minor damage to the station and to components of the photovoltaic system, the latter designed by MIT Lincoln Laboratory under US Department of Energy sponsorship, is described. This rare strike suggested the need for increased protection and more voltage-transient suppressors were added to those already in place as a preventive measure in the event that such a phenomenon reoccurs.

  14. Suppression of strike-slip fault systems

    NASA Astrophysics Data System (ADS)

    Curren, I. S.

    2012-12-01

    In orogens elongated parallel to a great circle about the Euler pole for the two bounding plates, theory requires simple-shear deformation in the form of distributed deformation or velocity discontinuities across strike-slip faults. This type of deformation, however, does not develop at all plate boundaries requiring toroidal motion. Using the global plate boundary model, PB2002 [Bird, 2003], as the basis for identifying areas where expected simple-shear deformation is absent or underdeveloped, it was also possible to identify two potential causes for this behavior: (1) the presence of extensive fracturing at right angles to the shear plane and (2) regional cover of flood basalts or andesites with columnar joints. To test this hypothesis, a new plane-stress finite-strain model was developed to study the effects of such pre-existing structures on the development of simple shear in a clay cake. A homogenous kaolinite-water mixture was poured into a deforming parallelogram box and partially dried to allow for brittle and plastic deformation at and below the surface of the clay, respectively. This was floated on a dense fluid foundation, effectively removing basal friction, and driven by a motor in a sinistral direction from the sides of the box. Control experiments produced classic Riedel model fault assemblages and discrete, through-going primary deformation zones (PDZs); experiments with pre-existing structures developed the same, though subdued and distributed, fault assemblages but did not develop through-going PDZs. Although formation of strike-slip faults was underdeveloped at the surface in clay with pre-existing structures, offset within the clay cake (measured, with respect to a fixed point, by markers on the clay surface) as a fraction of total offset of the box was consistently larger than that of the control experiments. This suggests that while the extent of surface faulting was lessened in clay with pre-existing structures, slip was still occurring at

  15. Centroid Position as a Function of Total Counts in a Windowed CMOS Image of a Point Source

    SciTech Connect

    Wurtz, R E; Olivier, S; Riot, V; Hanold, B J; Figer, D F

    2010-05-27

    We obtained 960,200 22-by-22-pixel windowed images of a pinhole spot using the Teledyne H2RG CMOS detector with un-cooled SIDECAR readout. We performed an analysis to determine the precision we might expect in the position error signals to a telescope's guider system. We find that, under non-optimized operating conditions, the error in the computed centroid is strongly dependent on the total counts in the point image only below a certain threshold, approximately 50,000 photo-electrons. The LSST guider camera specification currently requires a 0.04 arcsecond error at 10 Hertz. Given the performance measured here, this specification can be delivered with a single star at 14th to 18th magnitude, depending on the passband.

  16. Point measurements of mass balance of the Greenland Ice Sheet using precision vertical Global Positioning System (GPS) surveys

    NASA Astrophysics Data System (ADS)

    Hamilton, Gordon S.; Whillans, Ian M.

    2000-07-01

    Rates of ice sheet thickening or thinning in Greenland are measured using the coffee-can technique. This entails computing the difference in the vertical velocity of markers anchored in firn and the long-term rate of snow accumulation. The velocities are obtained from repeat surveys using the Global Positioning System (GPS). With corrections for densification and along-slope flow, this difference is the local mass balance. For two sites in western Greenland (Camp Century and a site just south of the EGIG line (Crawford Point)) results show ice sheet thinning. A third west Greenland site (inland from Upernavik) is close to balance. Two sites, Dye-2 in western Greenland and Summit, are thickening slowly.

  17. Estimation of precipitable water vapour using kinematic GNSS precise point positioning over an altitude range of 1 km

    NASA Astrophysics Data System (ADS)

    Webb, S. R.; Penna, N. T.; Clarke, P. J.; Webster, S.; Martin, I.

    2013-12-01

    The estimation of total precipitable water vapour (PWV) using kinematic GNSS has been investigated since around 2001, aiming to extend the use of static ground-based GNSS, from which PWV estimates are now operationally assimilated into numerical weather prediction models. To date, kinematic GNSS PWV studies suggest a PWV measurement agreement with radiosondes of 2-3 mm, almost commensurate with static GNSS measurement accuracy, but only shipborne experiments have so far been carried out. As a first step towards extending such sea level-based studies to platforms that operate at a range of altitudes, such as airplanes or land based vehicles, the kinematic GNSS estimation of PWV over an exactly repeated trajectory is considered. A data set was collected from a GNSS receiver and antenna mounted on a carriage of the Snowdon Mountain Railway, UK, which continually ascends and descends through 950 m of vertical relief. Static GNSS reference receivers were installed at the top and bottom of the altitude profile, and derived zenith wet delay (ZWD) was interpolated to the altitude of the train to provide reference values together with profile estimates from the 100 m resolution runs of the Met Office's Unified Model. We demonstrate similar GNSS accuracies as obtained from previous shipborne studies, namely a double difference relative kinematic GNSS ZWD accuracy within 14 mm, and a kinematic GNSS precise point positioning ZWD accuracy within 15 mm. The latter is a more typical airborne PWV estimation scenario i.e. without the reliance on ground-based GNSS reference stations. We show that the kinematic GPS-only precise point positioning ZWD estimation is enhanced by also incorporating GLONASS observations.

  18. Doctors' strikes and mortality: a review.

    PubMed

    Cunningham, Solveig Argeseanu; Mitchell, Kristina; Narayan, K M; Yusuf, Salim

    2008-12-01

    A paradoxical pattern has been suggested in the literature on doctors' strikes: when health workers go on strike, mortality stays level or decreases. We performed a review of the literature during the past forty years to assess this paradox. We used PubMed, EconLit and Jstor to locate all peer-reviewed English-language articles presenting data analysis on mortality associated with doctors' strikes. We identified 156 articles, seven of which met our search criteria. The articles analyzed five strikes around the world, all between 1976 and 2003. The strikes lasted between nine days and seventeen weeks. All reported that mortality either stayed the same or decreased during, and in some cases, after the strike. None found that mortality increased during the weeks of the strikes compared to other time periods. The paradoxical finding that physician strikes are associated with reduced mortality may be explained by several factors. Most importantly, elective surgeries are curtailed during strikes. Further, hospitals often re-assign scarce staff and emergency care was available during all of the strikes. Finally, none of the strikes may have lasted long enough to assess the effects of long-term reduced access to a physician. Nonetheless, the literature suggests that reductions in mortality may result from these strikes. PMID:18849101

  19. 14 CFR 35.38 - Lightning strike.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lightning strike. 35.38 Section 35.38... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by... lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller...

  20. 14 CFR 35.38 - Lightning strike.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Lightning strike. 35.38 Section 35.38... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by... lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller...

  1. 31 CFR 0.202 - Strikes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance: Treasury 1 2012-07-01 2012-07-01 false Strikes. 0.202 Section 0.202 Money and Finance: Treasury Office of the Secretary of the Treasury DEPARTMENT OF THE TREASURY EMPLOYEE RULES OF CONDUCT Rules of Conduct § 0.202 Strikes. Employees shall not strike against the Government....

  2. 31 CFR 0.202 - Strikes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance: Treasury 1 2013-07-01 2013-07-01 false Strikes. 0.202 Section 0.202 Money and Finance: Treasury Office of the Secretary of the Treasury DEPARTMENT OF THE TREASURY EMPLOYEE RULES OF CONDUCT Rules of Conduct § 0.202 Strikes. Employees shall not strike against the Government....

  3. 31 CFR 0.202 - Strikes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance: Treasury 1 2011-07-01 2011-07-01 false Strikes. 0.202 Section 0.202 Money and Finance: Treasury Office of the Secretary of the Treasury DEPARTMENT OF THE TREASURY EMPLOYEE RULES OF CONDUCT Rules of Conduct § 0.202 Strikes. Employees shall not strike against the Government....

  4. 31 CFR 0.202 - Strikes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance: Treasury 1 2014-07-01 2014-07-01 false Strikes. 0.202 Section 0.202 Money and Finance: Treasury Office of the Secretary of the Treasury DEPARTMENT OF THE TREASURY EMPLOYEE RULES OF CONDUCT Rules of Conduct § 0.202 Strikes. Employees shall not strike against the Government....

  5. 31 CFR 0.202 - Strikes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Strikes. 0.202 Section 0.202 Money and Finance: Treasury Office of the Secretary of the Treasury DEPARTMENT OF THE TREASURY EMPLOYEE RULES OF CONDUCT Rules of Conduct § 0.202 Strikes. Employees shall not strike against the Government....

  6. 14 CFR 35.38 - Lightning strike.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Lightning strike. 35.38 Section 35.38... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by... lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller...

  7. 14 CFR 35.38 - Lightning strike.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Lightning strike. 35.38 Section 35.38... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by... lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller...

  8. 14 CFR 35.38 - Lightning strike.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Lightning strike. 35.38 Section 35.38... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by... lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller...

  9. Estimation of Damage Preference From Strike Parameters

    SciTech Connect

    Canavan, G.H.

    1998-09-11

    Estimation of an opponent's damage preference is illustrated by discussing the sensitivity of stability indices and strike parameters to it and inverting the results to study the sensitivity of estimates to uncertainties in strikes. Costs and stability indices do not generally have the monotonicity and sensitivity needed to support accurate estimation. First and second strikes do. Second strikes also have proportionality, although they are not unambiguously interpretable. First strikes are observable and have the greatest overall power for estimation, whether linear or numerical solutions are used.

  10. Assessment of precipitable water vapor derived from ground-based BeiDou observations with Precise Point Positioning approach

    NASA Astrophysics Data System (ADS)

    Li, Min; Li, Wenwen; Shi, Chuang; Zhao, Qile; Su, Xing; Qu, Lizhong; Liu, Zhizhao

    2015-01-01

    Precipitable water vapor (PWV) estimation from Global Positioning System (GPS) has been extensively studied and used for meteorological applications. However PWV estimation using the emerging BeiDou Navigation Satellite System (BDS) is very limited. In this paper the PWV estimation strategy and the evaluation of the results inferred from ground-based BDS observations using Precise Point Positioning (PPP) method are presented. BDS and GPS data from 10 stations distributed in the Asia-Pacific and West Indian Ocean regions during the year 2013 are processed using the PANDA (Position and Navigation Data Analyst) software package. The BDS-PWV and GPS-PWV are derived from the BDS-only and GPS-only observations, respectively. The PPP positioning differences between BDS-only and GPS-only show a standard deviation (STD) <1 cm in the east and north components and 1-3 cm in vertical component. The BDS-PWV and GPS-PWV at the HKTU station (Hong Kong, China) is compared with PWV derived from a radiosonde station (about 1 km distance) over a 6-month period. The GPS-PWV shows a good agreement with radiosonde-PWV with a bias of 0.002 mm and a STD of 2.49 mm while BDS-PWV has with a bias of -2.04 mm and STD 2.68 mm with respect to radiosonde-PWV. This indicates that the PWV estimated from the BDS can achieve similar precision as PWV from GPS. The BDS-PWV is compared to GPS-PWV at 10 stations. The mean bias and STD of their differences at 10 stations are 0.78 mm and 1.77 mm, respectively. The mean root mean square (RMS) value is 2.00 mm by considering the GPS-PWV as reference truth. This again confirms that the BDS-PWV has a good agreement with the GPS-PWV. It clearly indicates that the BDS is ready for the high precision meteorological applications in the Asia-Pacific and West Indian Ocean regions and that BDS alone can be used for PWV estimation with an accuracy comparable to GPS.

  11. Rapid earthquake magnitude from real-time GPS precise point positioning for earthquake early warning and emergency response

    NASA Astrophysics Data System (ADS)

    Fang, Rongxin; Shi, Chuang; Song, Weiwei; Wang, Guangxing; Liu, Jingnan

    2014-05-01

    For earthquake early warning (EEW) and emergency response, earthquake magnitude is the crucial parameter to be determined rapidly and correctly. However, a reliable and rapid measurement of the magnitude of an earthquake is a challenging problem, especially for large earthquakes (M>8). Here, the magnitude is determined based on the GPS displacement waveform derived from real-time precise point positioning (PPP). The real-time PPP results are evaluated with an accuracy of 1 cm in the horizontal components and 2-3 cm in the vertical components, indicating that the real-time PPP is capable of detecting seismic waves with amplitude of 1cm horizontally and 2-3cm vertically with a confidence level of 95%. In order to estimate the magnitude, the unique information provided by the GPS displacement waveform is the horizontal peak displacement amplitude. We show that the empirical relation of Gutenberg (1945) between peak displacement and magnitude holds up to nearly magnitude 9.0 when displacements are measured with GPS. We tested the proposed method for three large earthquakes. For the 2010 Mw 7.2 El Mayor-Cucapah earthquake, our method provides a magnitude of M7.18±0.18. For the 2011 Mw 9.0 Tohoku-oki earthquake the estimated magnitude is M8.74±0.06, and for the 2010 Mw 8.8 Maule earthquake the value is M8.7±0.1 after excluding some near-field stations. We therefore conclude that depending on the availability of high-rate GPS observations, a robust value of magnitude up to 9.0 for a point source earthquake can be estimated within 10s of seconds or a few minutes after an event using a few GPS stations close to the epicenter. The rapid magnitude could be as a pre-requisite for tsunami early warning, fast source inversion, and emergency response is feasible.

  12. Numerical Modeling of Hohlraum Radiation Conditions: Spatial and Spectral Variations due to Sample Position, Beam Pointing, and Hohlraum Geometry

    SciTech Connect

    Cohen, D H; Landen, O L; MacFarlane, J J

    2005-01-25

    View-factor simulations are presented of the spatially varying radiation conditions inside double-ended gold hohlraums and single-ended gold hohlraums (''halfraums'') used in inertial confinement fusion (ICF) and high energy density (HED) physics experiments [J. Lindl, Phys. Plasmas 11, 339 (2004); M. D. Rosen, Phys. Plasmas 3, 1803 (1996)]. It is shown that in many circumstances, the common assumption that the hohlraum ''drive'' can be characterized by a single temperature is too simplistic. Specifically, the radiation conditions seen by an experimental package can differ significantly from the wall reemission measured through diagnostic holes or laser entrance holes (LEHs) by absolutely calibrated detectors. Furthermore, even in situations where the radiation temperature is roughly the same for diagnostics and experimental packages, or for packages at different locations, the spectral energy distributions can vary significantly, due to the differing fractions of reemitting wall, laser hot spots, and LEHs seen from different locations. We find that the spatial variation of temperature, and especially the differences between what diagnostics looking in the LEH measure vs. the radiation temperature on wall-mounted experimental packages, is generally greater for double-ended hohlraums than it is for halfraums. View-factor simulations can also be used to explore experimental variables (halfraum length and geometry, sample position, and beam pointing) that can be adjusted in order to, for example, maximize the radiation flux onto a sample, or other package. In this vein, simulations of hohlraums and halfraums with LEH shields are also presented.

  13. BeiDou phase bias estimation and its application in precise point positioning with triple-frequency observable

    NASA Astrophysics Data System (ADS)

    Gu, Shengfeng; Lou, Yidong; Shi, Chuang; Liu, Jingnan

    2015-10-01

    At present, the BeiDou system (BDS) enables the practical application of triple-frequency observable in the Asia-Pacific region, of many possible benefits from the additional signal; this study focuses on exploiting the contribution of zero difference (ZD) ambiguity resolution (AR) to the precise point positioning (PPP). A general modeling strategy for multi-frequency PPP AR is presented, in which, the least squares ambiguity decorrelation adjustment (LAMBDA) method is employed in ambiguity fixing based on the full variance-covariance ambiguity matrix generated from the raw data processing model. Because of the reliable fixing of BDS L1 ambiguity faces more difficulty, the LAMBDA method with partial ambiguity fixing is proposed to enable the independent and instantaneous resolution of extra wide-lane (EWL) and wide-lane (WL). This mechanism of sequential ambiguity fixing is demonstrated for resolving ZD satellite phase bias and performing triple-frequency PPP AR with two reference station networks with a typical baseline of up to 400 and 800 km, respectively. Tests show that about of the EWL and WL phase bias of BDS has a consistency of better than 0.1 cycle, and this value decreases to 80 % for L1 phase bias for Experiment I, while all the solutions of Experiment II have a similar RMS of about 0.12 cycles. In addition, the repeatability of the daily mean phase bias agree to 0.093 cycles and 0.095 cycles for EWL and WL on average, which is much smaller than 0.20 cycles of L1. To assess the improvement of fixed PPP brought by applying the third frequency signal as well as the above phase bias, various ambiguity fixing strategy are considered in the numerical demonstration. It is shown that the impact of the additional signal is almost negligible when only float solution involved. It is also shown that by fixing EWL and WL together, as opposed to the single ambiguity fixing, will leads to an improvement in PPP accuracy by about on average. Attributed to the efficient

  14. Impacts of real-time satellite clock errors on GPS precise point positioning-based troposphere zenith delay estimation

    NASA Astrophysics Data System (ADS)

    Shi, Junbo; Xu, Chaoqian; Li, Yihe; Gao, Yang

    2015-08-01

    Global Positioning System (GPS) has become a cost-effective tool to determine troposphere zenith total delay (ZTD) with accuracy comparable to other atmospheric sensors such as the radiosonde, the water vapor radiometer, the radio occultation and so on. However, the high accuracy of GPS troposphere ZTD estimates relies on the precise satellite orbit and clock products available with various latencies. Although the International GNSS Service (IGS) can provide predicted orbit and clock products for real-time applications, the predicted clock accuracy of 3 ns cannot always guarantee the high accuracy of troposphere ZTD estimates. Such limitations could be overcome by the use of the newly launched IGS real-time service which provides 5 cm orbit and 0.2-1.0 ns (an equivalent range error of 6-30 cm) clock products in real time. Considering the relatively larger magnitude of the clock error than that of the orbit error, this paper investigates the effect of real-time satellite clock errors on the GPS precise point positioning (PPP)-based troposphere ZTD estimation. Meanwhile, how the real-time satellite clock errors impact the GPS PPP-based troposphere ZTD estimation has also been studied to obtain the most precise ZTD solutions. First, two types of real-time satellite clock products are assessed with respect to the IGS final clock product in terms of accuracy and precision. Second, the real-time GPS PPP-based troposphere ZTD estimation is conducted using data from 34 selected IGS stations over three independent weeks in April, July and October, 2013. Numerical results demonstrate that the precision, rather than the accuracy, of the real-time satellite clock products impacts the real-time PPP-based ZTD solutions more significantly. In other words, the real-time satellite clock product with better precision leads to more precise real-time PPP-based troposphere ZTD solutions. Therefore, it is suggested that users should select and apply real-time satellite products with

  15. The differences in the isoelectric points of biofilm-positive and biofilm-negative Candida parapsilosis strains.

    PubMed

    Ruzicka, Filip; Horka, Marie; Hola, Veronika; Kubesova, Anna; Pavlik, Tomas; Votava, Miroslav

    2010-03-01

    The isoelectric points of 39 Candida parapsilosis strains were determined by means of capillary isoelectric focusing. The value of the isoelectric point corresponded well with cell surface hydrophobicity, as well as with the ability to form biofilm in these yeasts. PMID:20079385

  16. Rydberg-Klein-Rees 1-Sigma-positive potential curve turning points for the isotopes of carbon monoxide

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Goorvitch, D.

    1982-01-01

    First order RKR turning points were computed for (C-12)O16, (C-12)O17, (C-13)O16, (C-12)O18, and (C-13)O18 for vibrational levels up to v = 40. These turning points should be useful in the numerical computation of matrix elements of powers of the internuclear separation.

  17. The 1982 direct strike lightning data

    NASA Technical Reports Server (NTRS)

    Thomas, M. E.; Pitts, F. L.

    1983-01-01

    Wideband waveforms data which were obtained during the 1982 direct-strike lightning tests utilizing the NASA F106-B aircraft specially instrumented for lightning electromagnetic measurements. The aircraft was operated in a thunderstorm environment to elicit strikes to the aircraft during this testing period. Electromagnetic field data were recorded to both attached lightning and free field excitation of the aircraft.

  18. 14 CFR 29.631 - Bird strike.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Bird strike. 29.631 Section 29.631... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.631 Bird strike. The... safe landing (for Category B) after impact with a 2.2-lb (1.0 kg) bird when the velocity of...

  19. 14 CFR 29.631 - Bird strike.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Bird strike. 29.631 Section 29.631... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.631 Bird strike. The... safe landing (for Category B) after impact with a 2.2-lb (1.0 kg) bird when the velocity of...

  20. 14 CFR 29.631 - Bird strike.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Bird strike. 29.631 Section 29.631... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.631 Bird strike. The... safe landing (for Category B) after impact with a 2.2-lb (1.0 kg) bird when the velocity of...

  1. The Strike from the Students' Viewpoint.

    ERIC Educational Resources Information Center

    Grayson, J. Paul

    In the fifth and sixth weeks of a faculty strike at York University (Ontario), a survey was undertaken to assess student perceptions of the strike, its benefits, and its costs. Respondents were 502 randomly selected full-time undergraduate students in several disciplines. Survey questions were developed in student focus groups. The report…

  2. 14 CFR 29.631 - Bird strike.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Bird strike. 29.631 Section 29.631... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.631 Bird strike. The... safe landing (for Category B) after impact with a 2.2-lb (1.0 kg) bird when the velocity of...

  3. 14 CFR 29.631 - Bird strike.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bird strike. 29.631 Section 29.631... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.631 Bird strike. The... safe landing (for Category B) after impact with a 2.2-lb (1.0 kg) bird when the velocity of...

  4. GLONASS Precise Point Positioning with Ambiguity Resolution (PPP-AR) and its Integration with GPS for Earthquake Early Warning

    NASA Astrophysics Data System (ADS)

    Bock, Y.; Geng, J.; Avallone, A.; Ganas, A.; Melgar, D.; Riquelme, S.

    2015-12-01

    GPS has been recognized as an essential technique to measure static and dynamic displacements for earthquake early warning (EEW), in particular for near-field large earthquake monitoring where broadband seismometers clip, filtering of strong-motion accelerometer data eliminates the static component, and seismic data are affected by magnitude saturation. We have developed a prototype EEW system for the U.S. West Coast using real-time precise point positioning with ambiguity resolution (PPP-AR). It includes about 200 GPS stations spanning the areas of greatest seismic risk: Cascadia, the San Francisco Bay Area and southern California, using IGS ultra-rapid orbits and a North-America based GPS network well outside the region of expected deformation to estimate satellite clock and fractional cycle biases. We have analyzed, retrospectively in real time, earthquakes from Mw5.1 to Mw9.0; we can detect dynamic displacements with a precision of about one cm, but we've encountered several issues that could improve our operational system. Reinitialization of the integer-cycle phase ambiguities is problematic when a (not unusual) data gap of more than about 5 minutes is encountered. Also, ambiguity resolution is less reliable when there are only a limited number (six or less) of GPS satellites available. Nowadays, GNSS is evolving to a true multi-constellation environment with GLONASS having been restored to a 24-satellite constellation in 2012. We present a method for GNSS (GPS+GLONASS) PPP-AR to improve on the performance of GPS PPP-AR in EEW. We find that GNSS-AR has higher reliability in achieving ambiguity-fixed solutions, improves vertical accuracy by 20%, reduces initialization time to less than 7 minutes from about 20 minutes, and reduces outlier rates from 1.2% to below 0.2%. We use three earthquakes to demonstrate GNSS-AR, the M7.8 2014 Iquique, Chile aftershock, and Mw 6.9 2014 North Aegean, Greece and Mw 6.3 2009 L'Aquila, Italy earthquakes.

  5. Atmosphere Mitigation in Precise Point Positioning Ambiguity Resolution for Earthquake Early Warning in the Western U.S.

    NASA Astrophysics Data System (ADS)

    Geng, J.; Bock, Y.; Reuveni, Y.

    2014-12-01

    Earthquake early warning (EEW) is a time-critical system and typically relies on seismic instruments in the area around the source to detect P waves (or S waves) and rapidly issue alerts. Thanks to the rapid development of real-time Global Navigation Satellite Systems (GNSS), a good number of sensors have been deployed in seismic zones, such as the western U.S. where over 600 GPS stations are collecting 1-Hz high-rate data along the Cascadia subduction zone, San Francisco Bay area, San Andreas fault, etc. GNSS sensors complement the seismic sensors by recording the static offsets while seismic data provide highly-precise higher frequency motions. An optimal combination of GNSS and accelerometer data (seismogeodesy) has advantages compared to GNSS-only or seismic-only methods and provides seismic velocity and displacement waveforms that are precise enough to detect P wave arrivals, in particular in the near source region. Robust real-time GNSS and seismogeodetic analysis is challenging because it requires a period of initialization and continuous phase ambiguity resolution. One of the limiting factors is unmodeled atmospheric effects, both of tropospheric and ionospheric origin. One mitigation approach is to introduce atmospheric corrections into precise point positioning with ambiguity resolution (PPP-AR) of clients/stations within the monitored regions. NOAA generates hourly predictions of zenith troposphere delays at an accuracy of a few centimeters, and 15-minute slant ionospheric delays of a few TECU (Total Electron Content Unit) accuracy from both geodetic and meteorological data collected at hundreds of stations across the U.S. The Scripps Orbit and Permanent Array Center (SOPAC) is experimenting with a regional ionosphere grid using a few hundred stations in southern California, and the International GNSS Service (IGS) routinely estimates a Global Ionosphere Map using over 100 GNSS stations. With these troposphere and ionosphere data as additional

  6. The Verification of Influence of the Point "C" Position from Given Interval to Solving Systems with Highspeed Feedback

    NASA Astrophysics Data System (ADS)

    Bajčičáková, Ingrida; Jurovatá, Dominika

    2015-08-01

    This article deals with the design of effective numerical scheme for solving three point boundary value problems for second-order nonlinear singularly perturbed differential equations with initial conditions. Especially, it is focused on the analysis of the solutions when the point c from given interval is not the centre of this interval. The obtained system of nonlinear algebraic equations is solved by Newthon-Raphson method in MATLAB. It also verifies the convergence of approximate solutions of an original problem to the solution of reduced problem. We discuss the solution of a given problem with the situation when the point c is in the middle of the given interval.

  7. Accuracy analysis on C/A code and P(Y) code pseudo-range of GPS dual frequency receiver and application in point positioning

    NASA Astrophysics Data System (ADS)

    Peng, Xiuying; Fan, Shijie; Guo, Jiming

    2008-10-01

    When the Anti-Spoofing (A-S) is active, the civilian users have some difficulties in using the P(Y) code for precise navigation and positioning. Z-tracking technique is one of the effective methods to acquire the P(Y) code. In this paper, the accuracy of pseudoranges from C/A code and P(Y) code for dual frequency GPS receiver is discussed. The principle of measuring the encrypted P(Y) code is described firstly, then a large data set from IGS tracking stations is utilized for analysis and verification with the help of a precise point positioning software developed by authors. Especially, P(Y) code pseudoranges of civilian GPS receivers allow eliminating/reducing the effect of ionospheric delay and improve the precision of positioning. The point positioning experiments for this are made in the end.

  8. A study on the influence of operating circuit on the position of emission point of fluorescent lamp

    NASA Astrophysics Data System (ADS)

    Uetsuki, Tadao; Genba, Yuki; Kanda, Takashi

    2009-10-01

    High efficiency fluorescent lamp systems driven by high frequency are very popular for general lighting. Therefore it is very beneficial to be able to predict the lamp's life before the lamp dying, because people can buy a new lamp just before the lamp dying and need not have stocks. In order to judge the lifetime of a lamp it is very useful to know where the emission point is on the electrode filament. With regard to a method for grasping the emission point, it has been reported that the distance from the emission point to the end of the filament can be calculated by measuring the voltage across the filament and the currents flowing in both ends of the filament. The lamp's life can be predicted by grasping the movement of the emission point with operating time. Therefore it is very important to confirm whether the movement of the emission point changes or not when the operating circuit is changed. The authors investigated the difference in the way the emission points moved for two lamp systems which are very popular. One system had an electronic ballast having an auxiliary power source for the heating cathode. Another system had an electronic ballast with no power source, but with a capacitor connected to the lamp in parallel. In this presentation these measurement results will be reported.

  9. Collective Bargaining and Strikes Among Physicians

    PubMed Central

    Keith, Stephen N.

    1984-01-01

    Unlike employees in other sectors of the economy, health care workers are directed toward one ultimate goal: making people well and keeping them healthy. The development of collective bargaining and union activities during this century has had a great impact on all industries in the United States and the western world. However, only in recent years have workers in the health care sector been affected by the organized labor movement. The history of collective bargaining and strikes among physicians, the key decision-makers in the health care sector, is even more recent. Because of their central position, physicians' collective activity has had and will continue to have tremendous implications for the viability of the present health care system and the quality of patient care. Even though most physicians continue to function as individual, entrepreneurial service providers and “professionals,” physicians as a group are more frequently being seen as members of a utility like industry. Their importance to individuals and society as a whole, it can be argued, is second to none; if physicians refuse to work there can be no worse set of outcomes. To estimate the potential future impact of growing collective action on the part of physicians, this article explores the general historical developments. PMID:6389889

  10. Be prepared should Legionella strike.

    PubMed

    Steel, Andrew

    2013-03-01

    When measures to prevent Legionella fail, and a positive result is returned from the laboratory, there is an imperative to act fast to stamp infection out, but taking the right action requires a rigorous approach. So says Andrew Steel, managing director of Airmec, a provider of essential air and water services solutions. Here he explains the legal and other obligations of health estates managers in taking all possible steps to prevent a Legionella outbreak, and, when they do face one, sets out the key remedial steps, and outlines what regulators or HSE personnel will expect to see as 'evidence' that sufficient 'duty of care' has been taken. PMID:23573686

  11. Tsunami Hazards From Strike-Slip Earthquakes

    NASA Astrophysics Data System (ADS)

    Legg, M. R.; Borrero, J. C.; Synolakis, C. E.

    2003-12-01

    Strike-slip faulting is often considered unfavorable for tsunami generation during large earthquakes. Although large strike-slip earthquakes triggering landslides and then generating substantial tsunamis are now recognized hazards, many continue to ignore the threat from submarine tectonic displacement during strike-slip earthquakes. Historical data record the occurrence of tsunamis from strike-slip earthquakes, for example, 1906 San Francisco, California, 1994 Mindoro, Philippines, and 1999 Izmit, Turkey. Recognizing that strike-slip fault zones are often curved and comprise numerous en echelon step-overs, we model tsunami generation from realistic strike-slip faulting scenarios. We find that tectonic seafloor uplift, at a restraining bend or"pop-up" structure, provides an efficient mechanism to generate destructive local tsunamis; likewise for subsidence at divergent pull-apart basin structures. Large earthquakes on complex strike-slip fault systems may involve both types of structures. The California Continental Borderland is a high-relief submarine part of the active Pacific-North America transform plate boundary. Natural harbors and bays created by long term vertical motion associated with strike-slip structural irregularities are now sites of burgeoning population and major coastal infrastructure. Significant local tsunamis generated by large strike-slip earthquakes pose a serious, and previously unrecognized threat. We model several restraining bend pop-up structures offshore southern California to quantify the local tsunami hazard. Maximum runup derived in our scenarios ranges from one to several meters, similar to runup observed from the 1994 Mindoro, Philippines, (M=7.1) earthquake. The runup pattern is highly variable, with local extremes along the coast. We only model the static displacement field for the strike-slip earthquake source; dynamic effects of moving large island or submerged banks laterally during strike-slip events remains to be examined

  12. Beyond the basics: lightning-strike injuries.

    PubMed

    Mistovich, Joseph J; Krost, William S; Limmer, Daniel D

    2008-03-01

    It is estimated that a lightning flash occurs approximately 8 million times per day throughout the world. Most strikes are benign and cause little damage to property and physical structures; however, when lightning strikes a person or group of people, it is a significant medical and potentially traumatic event that could lead to immediate death or permanent disability. By understanding some basic physics of lightning and pathophysiology of injuries associated with lightning strikes, EMS providers will be better prepared to identify assessment findings, anticipate complications and provide effective emergency care. PMID:18814638

  13. System and Method of Locating Lightning Strikes

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro J. (Inventor); Starr, Stanley O. (Inventor)

    2002-01-01

    A system and method of determining locations of lightning strikes has been described. The system includes multiple receivers located around an area of interest, such as a space center or airport. Each receiver monitors both sound and electric fields. The detection of an electric field pulse and a sound wave are used to calculate an area around each receiver in which the lighting is detected. A processor is coupled to the receivers to accurately determine the location of the lighting strike. The processor can manipulate the receiver data to compensate for environmental variables such as wind, temperature, and humidity. Further, each receiver processor can discriminate between distant and local lightning strikes.

  14. Lightning Strike in Pregnancy With Fetal Injury.

    PubMed

    Galster, Kellen; Hodnick, Ryan; Berkeley, Ross P

    2016-06-01

    Injuries from lightning strikes are an infrequent occurrence, and are only rarely noted to involve pregnant victims. Only 13 cases of lightning strike in pregnancy have been previously described in the medical literature, along with 7 additional cases discovered within news media reports. This case report presents a novel case of lightning-associated injury in a patient in the third trimester of pregnancy, resulting in fetal ischemic brain injury and long-term morbidity, and reviews the mechanics of lightning strikes along with common injury patterns of which emergency providers should be aware. PMID:27116922

  15. A Case Example of the Implementation of Schoolwide Positive Behavior Support in a High School Setting Using Change Point Test Analysis

    ERIC Educational Resources Information Center

    Bohanon, Hank; Fenning, Pamela; Hicks, Kira; Weber, Stacey; Thier, Kimberly; Aikins, Brigit; Morrissey, Kelly; Briggs, Alissa; Bartucci, Gina; McArdle, Lauren; Hoeper, Lisa; Irvin, Larry

    2012-01-01

    The purpose of this case study was to expand the literature base regarding the application of high school schoolwide positive behavior support in an urban setting for practitioners and policymakers to address behavior issues. In addition, the study describes the use of the Change Point Test as a method for analyzing time series data that are…

  16. Response to the DIAC Discussion Paper: "Review of the General Skilled Migration Points Test". Go8 Position Paper

    ERIC Educational Resources Information Center

    Group of Eight (NJ1), 2010

    2010-01-01

    The Group of Eight (Go8) applauds the government's intention to comprehensively reform the skilled migration program, and it welcomes the opportunity to submit this response to the General Skilled Migration (GSM) Points Test Discussion Paper. The Go8 has argued for some time that it is inappropriate to link international education to the skilled…

  17. Lightning Science: Five Ways Lightning Strikes People

    MedlinePlus

    ... Centers Products and Services Contact Us Glossary Lightning Science: Five Ways Lightning Strikes People It is not ... of a streamer injury. For more on the science of lightning: National Severe Storms Laboratory NWS Colorado ...

  18. Heart Attacks Striking Younger, Fatter Americans

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_157946.html Heart Attacks Striking Younger, Fatter Americans: Study Doctors, patients need ... 24, 2016 THURSDAY, March 24, 2016 (HealthDay News) -- Heart attack victims in the United States are becoming younger ...

  19. Cement mantle stress under retroversion torque at heel-strike.

    PubMed

    Afsharpoya, B; Barton, D C; Fisher, J; Purbach, B; Wroblewski, M; Stewart, T D

    2009-12-01

    The paper presents a theory of fixation failure and loosening in cemented total hip prostheses and proceeds to investigate this using an experimentally validated finite element model and two prosthesis types, namely the Charnley and the C-Stem. The study investigates the effects of retroversion torque occurring at heel-strike in combination with a loss of proximal cement/bone support and distal implant/cement support with a good distal cement/bone interface. A 3D finite element model was validated by comparison of femoral surface strains with those measured in an in vitro experimental simulation using an implanted Sawbone femur loaded in the heel-strike position and including a simplified representation of muscle forces. Results showed that the heel-strike position applies a high retroversion torque to the femoral stem that when combined with proximal debonding of the cement/bone interface and distal debonding of the implant/cement interface increases the strain transfer to the cement that may ultimately lead to the breakdown of the cement mantle leading on to osteolysis and loosening of the prostheses. Experimental fatigue testing of the implanted Charnley stem in a Sawbone femur produced cracks within the cement mantle that were located in positions of maximum stress supporting the finite element analysis results and theory of failure. PMID:19879794

  20. Higher Education-to-Work Transitions in the Knowledge Society: The Initial Transition and Positional Competition Point of View

    ERIC Educational Resources Information Center

    Lindberg, Matti

    2008-01-01

    This article presents an analysis of the higher education-to-work transition from the perspective of the competition for job positions between students and degree holders. The conceptual framework used addresses two factors influencing the success of policies that aim to support higher education-to-work transition of youth in a knowledge society:…

  1. Positive Behavior Supports: Using Class Dojo as a Token Economy Point System to Encourage and Maintain Good Behaviors

    ERIC Educational Resources Information Center

    Garcia, Eliana; Hoang, Dana

    2015-01-01

    The use of positive reinforcement sometimes gets lost in translation because educators forget the importance of acknowledging good behaviors. We instinctively tend to punish and give consequences because we often forget the importance of preventing undesired behaviors from occurring in the first place. More efforts should be spent on maintaining…

  2. Single Station System and Method of Locating Lightning Strikes

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro J. (Inventor); Starr, Stanley O. (Inventor)

    2003-01-01

    An embodiment of the present invention uses a single detection system to approximate a location of lightning strikes. This system is triggered by a broadband RF detector and measures a time until the arrival of a leading edge of the thunder acoustic pulse. This time difference is used to determine a slant range R from the detector to the closest approach of the lightning. The azimuth and elevation are determined by an array of acoustic sensors. The leading edge of the thunder waveform is cross-correlated between the various acoustic sensors in the array to determine the difference in time of arrival, AT. A set of AT S is used to determine the direction of arrival, AZ and EL. The three estimated variables (R, AZ, EL) are used to locate a probable point of the lightning strike.

  3. Issues and Outcomes of Teachers' Strikes, 1955-65.

    ERIC Educational Resources Information Center

    Goergen, Joseph H.; Keough, John J.

    This study analyzes the patterns of 40 teacher strikes between 1955 and 1965 by looking at (1) the issues and demands and (2) the outcomes and settlements. It is hypothesized that (1) teacher strikes fall into discernible patterns, (2) functional relationships exist between certain strike issues and outcomes and the strike itself, (3) strikes can…

  4. An Alternative Empirical Formula for Positive Corona Discharge I-V Characteristics in Point-to-Plate Electrode Geometry

    NASA Astrophysics Data System (ADS)

    A. Azooz, A.; Sabah, I. Waysi

    2014-03-01

    Experimental data are presented for a study on the dependence of the I-V characteristics of the corona discharge on pressure and electrode spacing using point-to-plane electrode configuration. These experimental data are obtained by a fast, automatic computer data-acquisition system. The data are used to suggest an alternative dimensionally self-consistent empirical equation for the parameterization of the I-V curves. The formula eliminates the need for any prior assumptions concerning the inception voltage, as is customary in this type of work.

  5. Video-speed detection of the absolute position of a light point on a large-area photodetector based on luminescent waveguides.

    PubMed

    Koeppe, Robert; Neulinger, Anton; Bartu, Petr; Bauer, S

    2010-02-01

    A large-area photosensor is presented that uses the coupling of light into the planar waveguide mode of a polycarbonate foil by luminescent dyes to extend the active area of silicon photodiodes attached to the surface of the foil in a regular pattern. The photodiode signal is directly related to the distance between the point where light is coupled into the foil and the photodiode, thus enabling a precise recovery of the position of a localized light signal hitting the foil. We present a large-area device that can trace the movement of a light point generated by a laser pointer hitting its surface. PMID:20174049

  6. Development of a GPS-aided motion measurement, pointing, and stabilization system for a Synthetic Aperture Radar. [Global Positioning System (GPS)

    SciTech Connect

    Fellerhoff, J.R.; Kohler, S.M.

    1991-01-01

    An advanced Synthetic Aperture Radar Motion Compensation System has been developed by Sandia National Laboratories (SNL). The system includes a miniaturized high accuracy ring laser gyro inertial measurement unit, a three axis gimbal pointing and stabilization assembly, a differential Global Positioning System (GPS) navigation aiding system, and a pilot guidance system. The system provides several improvements over previous SNL motion compensation systems and is capable of antenna stabilization to less than 0.01 degrees RMS and absolute position measurement to less than 5.0 meters RMS. These accuracies have been demonstrated in recent flight testing aboard a DHC-6-300 Twin Otter'' aircraft.

  7. Geometrical and total efficiencies of CdZnTe rectangular parallelepiped detector using arbitrary positioned point, plane, and volumetric sources.

    PubMed

    Hamzawy, A; Badawi, Mohamed S; Thabet, Abouzeid A; Gouda, Mona M; El-Khatib, Ahmed M; Abbas, Mahmoud I

    2016-02-01

    Gamma-ray detectors are widely used in many fields like environmental measurements, medicine, space science, and industry, where the detector geometrical, total, photopeak efficiencies and peak-to-total ratio could be required. The calculation of the detector efficiency depends mainly on the value of the geometrical efficiency, which depends on the solid angle subtended by the source-detector system. The present work introduces a direct analytical method to calculate the geometrical and total efficiencies of CdZnTe gamma-ray detector using off-axis isotropic radiating γ-ray [point, disk, and cylindrical] sources. To test the validity of the present work, the results are compared with some published data and also to prove how much it is important to determine the efficiency of difficult gamma-ray detection arrangement. PMID:26931896

  8. Geometrical and total efficiencies of CdZnTe rectangular parallelepiped detector using arbitrary positioned point, plane, and volumetric sources

    NASA Astrophysics Data System (ADS)

    Hamzawy, A.; Badawi, Mohamed S.; Thabet, Abouzeid A.; Gouda, Mona M.; El-Khatib, Ahmed M.; Abbas, Mahmoud I.

    2016-02-01

    Gamma-ray detectors are widely used in many fields like environmental measurements, medicine, space science, and industry, where the detector geometrical, total, photopeak efficiencies and peak-to-total ratio could be required. The calculation of the detector efficiency depends mainly on the value of the geometrical efficiency, which depends on the solid angle subtended by the source-detector system. The present work introduces a direct analytical method to calculate the geometrical and total efficiencies of CdZnTe gamma-ray detector using off-axis isotropic radiating γ-ray [point, disk, and cylindrical] sources. To test the validity of the present work, the results are compared with some published data and also to prove how much it is important to determine the efficiency of difficult gamma-ray detection arrangement.

  9. When Push Comes to Shove: Strikes in Higher Education.

    ERIC Educational Resources Information Center

    Magney, John

    2002-01-01

    To provide a better sense of how academic unions handle a strike situation, examines six unions who, between 1996 and 2000, went through strikes. Discusses the key issues and outcomes of the strikes. (EV)

  10. The Effects of Height and Distance on the Force Production and Acceleration in Martial Arts Strikes

    PubMed Central

    Bolander, Richard P.; Neto, Osmar Pinto; Bir, Cynthia A.

    2009-01-01

    Almost all cultures have roots in some sort of self defence system and yet there is relatively little research in this area, outside of a sports related environment. This project investigated different applications of strikes from Kung Fu practitioners that have not been addressed before in the literature. Punch and palm strikes were directly compared from different heights and distances, with the use of a load cell, accelerometers, and high speed video. The data indicated that the arm accelerations of both strikes were similar, although the force and resulting acceleration of the target were significantly greater for the palm strikes. Additionally, the relative height at which the strike was delivered was also investigated. The overall conclusion is that the palm strike is a more effective strike for transferring force to an object. It can also be concluded that an attack to the chest would be ideal for maximizing impact force and moving an opponent off balance. Key Points It has been determined that the palm strike is more effective than the punch for developing force and for transferring momentum, most likely the result of a reduced number of rigid links and joints. A strike at head level is less effective than a strike at chest level for developing force and transferring momentum. Distance plays an effect on the overall force and momentum changes, and most likely is dependent on the velocity of the limb and alignment of the bones prior to impact. The teaching of self defence for novices and law enforcement would benefit from including the palm strike as a high priority technique. PMID:24474886

  11. VARIATION OF STRIKE INCENTIVES WITH DAMAGE PREFERENCES

    SciTech Connect

    G. CANAVAN

    2001-08-01

    For START III level forces, strike allocations and magnitudes vary little with L, but first strike costs vary directly with L, which means that for K reflecting a preference for the survival of high value targets over their destruction and a preference for high value over military targets, the costs of action are far greater than those of inaction for a wide range of values of damage preference L. Thus, if both sides have much greater preferences for the survival of their high value targets than for military targets or destruction, they do not see a net incentive to strike, and crises are terminated by inaction. Recent decades suggest strong preferences for the survival of high value and that this has contributed to the lack of direct conflict during that period.

  12. Point-of-Care Testing in Bathhouses: A Narrative Inquiry into the Experience of Receiving a Positive Preliminary HIV Test Result.

    PubMed

    Genoway, Shyla; Caine, Vera; Singh, Ameeta E; Estefan, Andrew

    2016-01-01

    With a call to increase the accessibility of HIV testing, point-of-care testing for HIV is being readily adopted, but little attention has been paid to the experiences of people being tested at HIV point-of-care sites. Some testing environments, such as bathhouses, promote testing for HIV in higher-risk groups. In this narrative inquiry study we explored the experiences of people testing positive for HIV through point-of-care while at a bathhouse. Three narrative threads for reconsidering the practice were identified: (a) seeing complexities, understanding testing decisions in relation to time, place, and social context; (b) recognizing the impact and significance of secret and silent stories; and (c) tentative and tension-filled connections to care. It is important to understand testing experiences across time, place, and in diverse social contexts. These experiences are embedded within the larger life histories of people and raise questions about adequate support, follow-up, and counseling. PMID:26900014

  13. Position-dependent velocity of an effective temperature point for the estimation of the thermal diffusivity of solids

    NASA Astrophysics Data System (ADS)

    Balachandar, Settu; Shivaprakash, N. C.; Kameswara Rao, L.

    2016-01-01

    A new approach is proposed to estimate the thermal diffusivity of optically transparent solids at ambient temperature based on the velocity of an effective temperature point (ETP), and by using a two-beam interferometer the proposed concept is corroborated. 1D unsteady heat flow via step-temperature excitation is interpreted as a ‘micro-scale rectilinear translatory motion’ of an ETP. The velocity dependent function is extracted by revisiting the Fourier heat diffusion equation. The relationship between the velocity of the ETP with thermal diffusivity is modeled using a standard solution. Under optimized thermal excitation, the product of the ‘velocity of the ETP’ and the distance is a new constitutive equation for the thermal diffusivity of the solid. The experimental approach involves the establishment of a 1D unsteady heat flow inside the sample through step-temperature excitation. In the moving isothermal surfaces, the ETP is identified using a two-beam interferometer. The arrival-time of the ETP to reach a fixed distance away from heat source is measured, and its velocity is calculated. The velocity of the ETP and a given distance is sufficient to estimate the thermal diffusivity of a solid. The proposed method is experimentally verified for BK7 glass samples and the measured results are found to match closely with the reported value.

  14. Determinants of Strike-Related Militancy: An Analysis of a University Faculty Strike.

    ERIC Educational Resources Information Center

    McClendon, John A.; Klaas, Brian

    1993-01-01

    During a 1990 Temple University faculty strike, three types of militancy (voting to strike, voting to defy injunction, picketing) had different determinants; for example, social support and union commitment related to riskier types. Other variables related to militancy included attitudes toward job, union, and militancy. (SK)

  15. Transmission gap, Bragg-like reflection, and Goos-Haenchen shifts near the Dirac point inside a negative-zero-positive index metamaterial slab

    SciTech Connect

    Chen Xi; Wang Ligang; Li Chunfang

    2009-10-15

    Motivated by the realization of the Dirac point (DP) with a double-cone structure for optical field in the negative-zero-positive index metamaterial (NZPIM), the reflection, transmission, and Goos-Haenchen (GH) shifts inside the NZPIM slab are investigated. Due to the linear Dirac dispersion, the transmission as the function of the frequency has a gap, thus, the corresponding reflection has a frequency or wavelength window for the perfect reflection, which is similar to the Bragg reflection in the one-dimensional photonic crystals. Near the DP, the associated GH shifts in the transmission and reflection can be changed from positive to negative with increasing the wavelength. These negative and positive shifts can also be enhanced by transmission resonances when the frequency is far from that at the DP. All these phenomena will lead to some potential applications in the integrated optics and optical devices.

  16. Position-addressable digital laser scanning point fluorescence microscopy with a Blu-ray disk pickup head

    PubMed Central

    Tsai, Rung-Ywan; Chen, Jung-Po; Lee, Yuan-Chin; Huang, Chun-Chieh; Huang, Tai-Ting; Chiang, Hung-Chih; Cheng, Chih-Ming; Lo, Feng-Hsiang; Chang, Sheng-Li; Weng, Kuo-Yao; Chung, Lung-Pin; Chen, Jyh-Chern; Tiao, Golden

    2014-01-01

    A compact and position-addressable blue ray scanning microscope (BSM) based on a commercially available Blu-ray disk pickup head (PUH) is developed for cell imaging with high resolution and low cost. The BSM comprises two objective lenses with numerical apertures (NAs) of 0.85 and 0.6 for focusing blue and red laser beams, respectively, on the sample slide. The blue and red laser beams are co-located adjacent to each other and move synchronously. A specially designed sample slide is used with a sample area and an address-patterned area for sample holding and address recognition, respectively. The blue laser beam is focused on the sample area and is used for fluorescent excitation and image capturing, whereas the red laser beam is focused on the address-patterned area and is used for address recognition and dynamic focusing. The address-patterned area is divided into 310 sectors. The cell image of each sector of the sampling area has a corresponding address pattern. Fluorescence images of monkey-derived kidney epithelial cells and fibroblast cells in which the F-actin is stained with fluorophore phalloidin CF 405 are measured by the BSM, with results comparable to those measured by a Leica TCS CP2 confocal microscope. The cell image of an area of interest can be easily tracked based on the coded address, and a large-area sample image can be accurately reconstructed from the sector images. PMID:24575338

  17. The Chicago Teachers Strike and Its Public

    ERIC Educational Resources Information Center

    Shuffelton, Amy B.

    2014-01-01

    This article considers the 2012 Chicago Teachers Strike in light of John Dewey's "The Public and Its Problems." It engages Dewey's conceptualization of practical reason to challenge the educational reform movement's commitment to technocratic decision-making.

  18. Protecting Your Park When Lightning Strikes.

    ERIC Educational Resources Information Center

    Frydenlund, Marvin M.

    1987-01-01

    A formula for assessing specific risk of lightning strikes is provided. Recent legal cases are used to illustrate potential liability. Six actions park managers can take to minimize danger from lightning are presented, and commonsense rules which should be publicly posted are listed. (MT)

  19. STS-135 Launch Pad Lightning Strike

    NASA Video Gallery

    A pair of lightning strikes occurred near launch pad 39-A at NASA's Kennedy Space Center at 12:31 p.m. and 12:40 p.m. EDT on July 7. The first struck the water tower 515 feet from the pad and the s...

  20. Television News and the Miners' Strike.

    ERIC Educational Resources Information Center

    Cumberbatch, Guy; And Others

    A content analysis was performed on all of the BBC (British Broadcasting Corporation) Nine O'Clock News and ITV (Independent Television) News at Ten programs that were broadcast during Britain's year-long miners' strike--March 1984-March 1985--and a four-month sample of Channel 4 news to examine how television news covered a protracted story of…

  1. What to Expect During a Teachers' Strike.

    ERIC Educational Resources Information Center

    Long, Jerri

    1987-01-01

    This two-page table charts the range of union activities, their adversarial intent, and possible administrative counterstrategies during a typical teacher strike. Twenty-four activities are covered, from peaceful demonstrations (like picketing), marches, and candlelight vigils, to harassments like nails in tires and telephone threats. (MLH)

  2. Endgame Is Eyed in Chicago Strike

    ERIC Educational Resources Information Center

    Sawchuk, Stephen

    2012-01-01

    A strike last week by some 29,000 teachers in Chicago pushed long-simmering tensions over deeply divisive school improvement ideas--including changes in teacher evaluation and the takeover or closure of underperforming schools--into the national spotlight. A framework for a tentative agreement emerged last Friday, and the union's house of…

  3. Registration of 'FirstStrike' Slender Wheatgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'FirstStrike' slender wheatgrass [Elymus trachycaulus (Link) Gould ex Shinners] was developed by a research team at the USDA-ARS-Forage and Range Research Laboratory and collaborators at the United States Army - Engineer Research and Development Center and was released on 16 October 2006. FirstStri...

  4. Teaching Striking/Fielding Concepts in Cricket

    ERIC Educational Resources Information Center

    Turner, Adrian P.

    2004-01-01

    This article presents activities for developing striking/fielding concepts in modified cricket games. Though not as familiar to American children, cricket is emerging as the second (to soccer) most popular game in the world. The novelty of the skills provides an appropriate learning challenge for all students while reinforcing concepts and…

  5. Upward streamers produced by a lightning strike to radio transmission towers

    NASA Technical Reports Server (NTRS)

    Krider, E. Philip; Wetmore, Ralph H.

    1987-01-01

    A lightning strike to the center of three 78-m radio transmission towers produced upward discharges with lengths of 40 and 79 m from each of the neighboring towers. This strike also caused a number of insulators on guy wires that supported the tower to flash over, and the locations of these points and the two-dimensional geometry of the discharge channels are projected onto a vertical plane that is centered on the tower.

  6. Tightly Coupled Integration of GPS Ambiguity Fixed Precise Point Positioning and MEMS-INS through a Troposphere-Constrained Adaptive Kalman Filter

    PubMed Central

    Han, Houzeng; Xu, Tianhe; Wang, Jian

    2016-01-01

    Precise Point Positioning (PPP) makes use of the undifferenced pseudorange and carrier phase measurements with ionospheric-free (IF) combinations to achieve centimeter-level positioning accuracy. Conventionally, the IF ambiguities are estimated as float values. To improve the PPP positioning accuracy and shorten the convergence time, the integer phase clock model with between-satellites single-difference (BSSD) operation is used to recover the integer property. However, the continuity and availability of stand-alone PPP is largely restricted by the observation environment. The positioning performance will be significantly degraded when GPS operates under challenging environments, if less than five satellites are present. A commonly used approach is integrating a low cost inertial sensor to improve the positioning performance and robustness. In this study, a tightly coupled (TC) algorithm is implemented by integrating PPP with inertial navigation system (INS) using an Extended Kalman filter (EKF). The navigation states, inertial sensor errors and GPS error states are estimated together. The troposphere constrained approach, which utilizes external tropospheric delay as virtual observation, is applied to further improve the ambiguity-fixed height positioning accuracy, and an improved adaptive filtering strategy is implemented to improve the covariance modelling considering the realistic noise effect. A field vehicular test with a geodetic GPS receiver and a low cost inertial sensor was conducted to validate the improvement on positioning performance with the proposed approach. The results show that the positioning accuracy has been improved with inertial aiding. Centimeter-level positioning accuracy is achievable during the test, and the PPP/INS TC integration achieves a fast re-convergence after signal outages. For troposphere constrained solutions, a significant improvement for the height component has been obtained. The overall positioning accuracies of the height

  7. Tightly Coupled Integration of GPS Ambiguity Fixed Precise Point Positioning and MEMS-INS through a Troposphere-Constrained Adaptive Kalman Filter.

    PubMed

    Han, Houzeng; Xu, Tianhe; Wang, Jian

    2016-01-01

    Precise Point Positioning (PPP) makes use of the undifferenced pseudorange and carrier phase measurements with ionospheric-free (IF) combinations to achieve centimeter-level positioning accuracy. Conventionally, the IF ambiguities are estimated as float values. To improve the PPP positioning accuracy and shorten the convergence time, the integer phase clock model with between-satellites single-difference (BSSD) operation is used to recover the integer property. However, the continuity and availability of stand-alone PPP is largely restricted by the observation environment. The positioning performance will be significantly degraded when GPS operates under challenging environments, if less than five satellites are present. A commonly used approach is integrating a low cost inertial sensor to improve the positioning performance and robustness. In this study, a tightly coupled (TC) algorithm is implemented by integrating PPP with inertial navigation system (INS) using an Extended Kalman filter (EKF). The navigation states, inertial sensor errors and GPS error states are estimated together. The troposphere constrained approach, which utilizes external tropospheric delay as virtual observation, is applied to further improve the ambiguity-fixed height positioning accuracy, and an improved adaptive filtering strategy is implemented to improve the covariance modelling considering the realistic noise effect. A field vehicular test with a geodetic GPS receiver and a low cost inertial sensor was conducted to validate the improvement on positioning performance with the proposed approach. The results show that the positioning accuracy has been improved with inertial aiding. Centimeter-level positioning accuracy is achievable during the test, and the PPP/INS TC integration achieves a fast re-convergence after signal outages. For troposphere constrained solutions, a significant improvement for the height component has been obtained. The overall positioning accuracies of the height

  8. Assessment of Three Tropospheric Delay Models (IGGtrop, EGNOS and UNB3m) Based on Precise Point Positioning in the Chinese Region.

    PubMed

    Zhang, Hongxing; Yuan, Yunbin; Li, Wei; Li, Ying; Chai, Yanju

    2016-01-01

    Tropospheric delays are one of the main sources of errors in the Global Navigation Satellite System (GNSS). They are usually corrected by using tropospheric delay models, which makes the accuracy of the models rather critical for accurate positioning. To provide references for suitable models to be chosen for GNSS users in China, we conduct herein a comprehensive study of the performances of the IGGtrop, EGNOS and UNB3m models in China. Firstly, we assess the models using 5 years' Global Positioning System (GPS) derived Zenith Tropospheric Delay (ZTD) series from 25 stations of the Crustal Movement Observation Network of China (CMONOC). Then we study the effects of the models on satellite positioning by using various Precise Point Positioning (PPP) cases with different tropospheric delay resolutions, the observation data processed in PPP is from 21 base stations of CMONOC for a whole year of 2012. The results show that: (1) the Root Mean Square (RMS) of the IGGtrop model is about 4.4 cm, which improves the accuracy of ZTD estimations by about 24% for EGNOS and 19% for UNB3m; (2) The positioning error in the vertical component of the PPP solution obtained by using the IGGtrop model is about 15.0 cm, which is about 30% and 21% smaller than those of the EGNOS and UNB3m models, respectively. In summary, the IGGtrop model achieves the best performance among the three models in the Chinese region. PMID:26805834

  9. Assessment of Three Tropospheric Delay Models (IGGtrop, EGNOS and UNB3m) Based on Precise Point Positioning in the Chinese Region

    PubMed Central

    Zhang, Hongxing; Yuan, Yunbin; Li, Wei; Li, Ying; Chai, Yanju

    2016-01-01

    Tropospheric delays are one of the main sources of errors in the Global Navigation Satellite System (GNSS). They are usually corrected by using tropospheric delay models, which makes the accuracy of the models rather critical for accurate positioning. To provide references for suitable models to be chosen for GNSS users in China, we conduct herein a comprehensive study of the performances of the IGGtrop, EGNOS and UNB3m models in China. Firstly, we assess the models using 5 years’ Global Positioning System (GPS) derived Zenith Tropospheric Delay (ZTD) series from 25 stations of the Crustal Movement Observation Network of China (CMONOC). Then we study the effects of the models on satellite positioning by using various Precise Point Positioning (PPP) cases with different tropospheric delay resolutions, the observation data processed in PPP is from 21 base stations of CMONOC for a whole year of 2012. The results show that: (1) the Root Mean Square (RMS) of the IGGtrop model is about 4.4 cm, which improves the accuracy of ZTD estimations by about 24% for EGNOS and 19% for UNB3m; (2) The positioning error in the vertical component of the PPP solution obtained by using the IGGtrop model is about 15.0 cm, which is about 30% and 21% smaller than those of the EGNOS and UNB3m models, respectively. In summary, the IGGtrop model achieves the best performance among the three models in the Chinese region. PMID:26805834

  10. Isoelectric points and surface hydrophobicity of Gram-positive cocci as determined by cross-partition and hydrophobic affinity partition in aqueous two-phase systems.

    PubMed Central

    Miörner, H; Albertsson, P A; Kronvall, G

    1982-01-01

    Thirty-nine streptococcal strains belonging to groups A, C, and G and 12 staphylococcal strains were investigated with respect to surface charge and hydrophobicity. Isoelectric points of the bacteria were determined by cross-partition experiments in dextran-polyethylene glycol two-phase systems containing charged polymers. The results obtained indicate that group A, C, and G streptococci have isoelectric points of pH 3.75 +/- 0.15 standard deviation. Staphylococci show an isoelectric point of around pH 2 and thereby differ markedly from the streptococci. Pretreatment of bacteria with human serum resulted in a significant change in the isoelectric points of streptococci. In a second series of experiments, an aqueous dextran-polyethylene glycol two-phase system containing polyethylene glycol palmitate or stearate was used to study the hydrophobic surface properties of the bacterial cells. The partition of the staphylococci was not influenced by the addition of up to 1% (wt/wt) polyethylene glycol palmitate or stearate, whereas the streptococci showed a large variation in affinity for polyethylene glycol-bound hydrophobic groups. The bacterial strains included in the study were also tested for uptake of human serum proteins. A positive correlation was found between the hydrophobic affinity of group A streptococci and the density of receptors for aggregated beta-2-microglobulin. PMID:7042571

  11. Strike planning against a target base with a value structure

    SciTech Connect

    Chrzanowski, P.L.

    1992-04-21

    With the signing of the Strategic Arms Reduction Treaty (START) and, with the end of the Cold War, two questions arise. How large should force reductions be in a START-II accord How much can the major nuclear powers reduce their nuclear arms and still maintain strategic stability. The results of the analysis presented here are summarized by the following five statements: (1) In the development of target lists, it is important to prioritize. A standard approach is to identify a break-point in the list of installations, to target only those facilities that are above the break-point, and to assign as many weapons as necessary to key installations to achieve damage goals. As an alternative, a systematic method is suggested here that uses the concept of target value. First, an ordinal list of targets must be developed. Then, values can be assigned to targets in a way that leads to reasonable set of targeting priorities and to a useful figure of merit to assess strike effectiveness. (2) Two complementary observations can be made, based on an analysis of optimum attack tactics against a target base with a value structure: It is not practical to size the stockpile based on the number of targets in the target set because a small change in the damage goal for the strike results in large change to the required inventory. By prioritizing targets, it is possible to make large reductions in the force structure while causing only small reductions in the expected target value damaged. (3) Prudence dictates building into strike plans hedges against degraded weapon performance. (4) The impact of defenses on the required offensive inventory depends on details about the management of defensive systems. (5) If timely information can be obtained about damage to targets so that follow-on weapons can be allocated only to undamaged targets, the number of weapons required to achieve the specified damage coal can be reduced significantly.

  12. Strike planning against a target base with a value structure

    SciTech Connect

    Chrzanowski, P.L.

    1992-04-21

    With the signing of the Strategic Arms Reduction Treaty (START) and, with the end of the Cold War, two questions arise. How large should force reductions be in a START-II accord? How much can the major nuclear powers reduce their nuclear arms and still maintain strategic stability. The results of the analysis presented here are summarized by the following five statements: (1) In the development of target lists, it is important to prioritize. A standard approach is to identify a break-point in the list of installations, to target only those facilities that are above the break-point, and to assign as many weapons as necessary to key installations to achieve damage goals. As an alternative, a systematic method is suggested here that uses the concept of target value. First, an ordinal list of targets must be developed. Then, values can be assigned to targets in a way that leads to reasonable set of targeting priorities and to a useful figure of merit to assess strike effectiveness. (2) Two complementary observations can be made, based on an analysis of optimum attack tactics against a target base with a value structure: It is not practical to size the stockpile based on the number of targets in the target set because a small change in the damage goal for the strike results in large change to the required inventory. By prioritizing targets, it is possible to make large reductions in the force structure while causing only small reductions in the expected target value damaged. (3) Prudence dictates building into strike plans hedges against degraded weapon performance. (4) The impact of defenses on the required offensive inventory depends on details about the management of defensive systems. (5) If timely information can be obtained about damage to targets so that follow-on weapons can be allocated only to undamaged targets, the number of weapons required to achieve the specified damage coal can be reduced significantly.

  13. Costs of strikes between vulnerable missile forces

    SciTech Connect

    Canavan, G.H.

    1997-02-01

    This note derives the first and second strike magnitudes and costs for strikes between vulnerable missile forces with multiple warheads. The extension to mixes with invulnerable missiles is performed in a companion note. Stability increases as the number of weapons per missile is reduced. The optimal allocation of weapons between missiles and value is significant in predicting the stability impact of the reduction of the number of weapons per missile at large numbers of missiles, less significant in reducing the number of missiles for fixed weapons per missile. At low numbers of missiles, the stability indices for singlet and triplet configurations are comparable, as are the number of weapons each would deliver on value targets.

  14. Central Hyperadrenergic State After Lightning Strike

    PubMed Central

    Parsaik, Ajay K.; Ahlskog, J. Eric; Singer, Wolfgang; Gelfman, Russell; Sheldon, Seth H.; Seime, Richard J.; Craft, Jennifer M.; Staab, Jeffrey P.; Kantor, Birgit; Low, Phillip A.

    2013-01-01

    Objective To describe and review autonomic complications of lightning strike. Methods Case report and laboratory data including autonomic function tests in a subject who was struck by lightning. Results A 24-year-old man was struck by lightning. Following that, he developed dysautonomia, with persistent inappropriate sinus tachycardia and autonomic storms, as well as posttraumatic stress disorder (PTSD) and functional neurologic problems. Interpretation The combination of persistent sinus tachycardia and episodic exacerbations associated with hypertension, diaphoresis, and agitation were highly suggestive of a central hyperadrenergic state with superimposed autonomic storms. Whether the additional PTSD and functional neurologic deficits were due to a direct effect of the lightning strike on the CNS or a secondary response is open to speculation. PMID:23761114

  15. Overview of cenozoic strike-slip displacement of the caribbean plate

    SciTech Connect

    Mann, P.

    1985-01-01

    Geologic and tectonic studies in the Caribbean region have traditionally focused on Cretaceous and Paleogene arc rocks which, for the most part, record a long period (approx. = 100 Ma) of plate convergence. Since the recognition of the plate structure of the Caribbean by Molnar and Sykes in 1969, there has been steadily increasing interest in mapping widespread ares of Neogene sedimentary and volcanic rocks that generally record a long period (65.-40 Ma) of eastward displacement of the Caribbean plate relative to the Americas. The purpose of this talk is to review different aspects of present knowledge on this strike-slip displacement, namely: 1) location of major strike-slip faults within the northern and southern plate boundary zones; 2) sense, offset, rate of slip of major strike-slip faults; 3) secondary deformational features related to strike-slip displacements; 4) intraplate deformational features related to interplate strike-slip movements; 5) relation of seismicity to major strike-slip faults; and 6) constraints imposed by strike-slip fault systems on plate motion models. Based on these observations, several critical problems which future studies might help resolve are pointed out.

  16. Systems tunnel linear shaped charge lightning strike

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    Simulated lightning strike testing of the systems tunnel linear shaped charge (LSC) was performed at the Thiokol Lightning Test Complex in Wendover, Utah, on 23 Jun. 1989. The test article consisted of a 160-in. section of the LSC enclosed within a section of the systems tunnel. The systems tunnel was bonded to a section of a solid rocket motor case. All test article components were full scale. The systems tunnel cover of the test article was subjected to three discharges (each discharge was over a different grounding strap) from the high-current generator. The LSC did not detonate. All three grounding straps debonded and violently struck the LSC through the openings in the systems tunnel floor plates. The LSC copper surface was discolored around the areas of grounding strap impact, and arcing occurred at the LSC clamps and LSC ends. This test verified that the present flight configuration of the redesigned solid rocket motor systems tunnel, when subjected to simulated lightning strikes with peak current levels within 71 percent of the worst-case lightning strike condition of NSTS-07636, is adequate to prevent LSC ignition. It is therefore recommended that the design remain unchanged.

  17. Preemptive Striking in Individual and Group Conflict.

    PubMed

    Mifune, Nobuhiro; Hizen, Yoichi; Kamijo, Yoshio; Okano, Yoshitaka

    2016-01-01

    In this study, we conducted a laboratory experiment to assess preemptive striking by and towards individuals or groups. In the framework of a preemptive strike game, we set the following four conditions: one person faced another person, one person faced a three-person group, a three-person group faced an individual, and a three-person group faced another three-person group. Previous studies have revealed that greed is activated when participants belong to a group, while fear is activated when participants interact with a group, and further, that attacking behaviors in the preemptive strike game are driven by fear. These observations led to a hypothesis that high attack rates would be realized when participants interact with a group, regardless of whether the participants make decisions as individuals or a group. The results of our experiment, however, rejected this hypothesis. Among the four conditions, the attack rate was highest when a three-person group faced an individual. As possible reasons for our observation, we discuss the potential threat stemming from the imbalance in the effectiveness of attack between individuals and groups, and the (incorrect) belief by groups that single individuals would be more likely to attack out of fear. PMID:27148871

  18. Preemptive Striking in Individual and Group Conflict

    PubMed Central

    Mifune, Nobuhiro; Hizen, Yoichi; Kamijo, Yoshio; Okano, Yoshitaka

    2016-01-01

    In this study, we conducted a laboratory experiment to assess preemptive striking by and towards individuals or groups. In the framework of a preemptive strike game, we set the following four conditions: one person faced another person, one person faced a three-person group, a three-person group faced an individual, and a three-person group faced another three-person group. Previous studies have revealed that greed is activated when participants belong to a group, while fear is activated when participants interact with a group, and further, that attacking behaviors in the preemptive strike game are driven by fear. These observations led to a hypothesis that high attack rates would be realized when participants interact with a group, regardless of whether the participants make decisions as individuals or a group. The results of our experiment, however, rejected this hypothesis. Among the four conditions, the attack rate was highest when a three-person group faced an individual. As possible reasons for our observation, we discuss the potential threat stemming from the imbalance in the effectiveness of attack between individuals and groups, and the (incorrect) belief by groups that single individuals would be more likely to attack out of fear. PMID:27148871

  19. Resistance, mobilization and militancy: nurses on strike.

    PubMed

    Briskin, Linda

    2012-12-01

    Drawing on nurses' strikes in many countries, this paper explores nurse militancy with reference to professionalism and the commitment to service; patriarchal practices and gendered subordination; and proletarianization and the confrontation with healthcare restructuring. These deeply entangled trajectories have had a significant impact on the work, consciousness and militancy of nurses and have shaped occupation-specific forms of resistance. They have produced a pattern of overlapping solidarities--occupational solidarity, gendered alliances and coalitions around healthcare restructuring--which have supported, indeed promoted, militancy among nurses, despite the multiple forces arrayed against them. The professional commitments of nurses to the provision of care have confronted healthcare restructuring, nursing shortages, intensification of work, precarious employment and gendered hierarchies with a militant discourse around the public interest, and a reconstitution and reclamation of 'caring', what I call the politicisation of caring. In fact, nurses' dedication to caring work in the late twentieth and early twenty-first centuries may encourage rather than dissuade them from going on strike. This paper uses a trans-disciplinary methodology, qualitative material in the form of strike narratives constructed from newspaper archives, and references to the popular and scholarly literature on nursing militancy. PMID:22059465

  20. Tracking and stepping control of the tip position of a scanning tunneling microscope by referring to atomic points and arrays on a regular crystalline surface

    NASA Astrophysics Data System (ADS)

    Aketagawa, Masato; Takada, Koji; Minao, Yoshihisa; Oka, Yuki; Lee, Jong-Doo

    1999-04-01

    In this article tracking and stepping control of the tip position of a scanning tunneling microscope (STM) by referring to atomic points and arrays on a regular crystalline surface which is used as a two-dimensional reference scale is described. Highly oriented pyrolytic graphite (HOPG) crystal, whose lattice spacing is approximately 0.25 nm, was used as the reference. To utilize the topographic features on the crystalline surface as a reference, a method for determining two-dimensional lateral gradient signals, i.e., the X, and Y axes gradient signals, of the crystalline surface was applied to the control. A rigid STM consisting of a tip scanner and a sample XY stage, and control instruments were developed. The X and Y axes gradient signals were obtained simultaneously using two-phase lock-in modulations of a tunneling current modulated with circular dither motion applied to the tip XY scanner. Modulation frequency and amplitude of the tip were 1 kHz and less than 0.04 nm, respectively. The sample XY stage was controlled for tip positioning by feedback of the X and Y axis gradient signals. First, the tracking control of the STM tip onto an atomic point of the HOPG surface for a maximum duration of about 10 min was performed. Second, tracking and motion control of the STM tip along a crystalline axis of the HOPG surface was demonstrated. The STM tip continued "back and forth" motion along the crystalline axis of the HOPG surface for a maximum duration of 200 s with a maximum tip speed of 6 nm/s. The maximum displacement deviation from the crystalline axis was less than 1/3 lattice spacing (˜0.08 nm). Third, the quantized stepping of the STM tip with lattice spacing stepping with a repetitive rate of 0.5 Hz along the crystalline axis was examined. The maximum displacement deviation from the crystalline axis was less than 1/2 lattice spacing (˜0.12 nm). The feasibility of tracking and stepping control of the STM tip position by referring to atomic points and arrays

  1. Acute transient hemiparesis induced by lightning strike.

    PubMed

    Rahmani, Seyed Hesam; Faridaalaee, Gholamreza; Jahangard, Samira

    2015-07-01

    According to data from the National Oceanic and Atmospheric Administration,in the years from 1959 to 1994, lightning was responsible for more than 3000 deaths and nearly 10,000 casualties. The most important characteristic features of lightning injuries are multisystem involvement and widely variable severity. Lightning strikes are primarily a neurologic injury that affects all 3 components of the nervous system: central, autonomic,and peripheral. Neurologic complications of lightning strikes vary from transient benign symptoms to permanent disability. Many patients experience a temporary paralysis called keraunoparalysis. Here we reported a 22-year-old mountaineer man with complaining of left sided hemiparesis after being hit by a lightning strike in the mountain 3 hours ago. There was no loss of consciousness at hitting time. On arrival the patient was alert, awake and hemodynamically stable. In neurologic examination cranial nerves were intact, left sided upper and lower extremity muscle force was I/V with a combination of complete sensory loss, and right-sided muscle force and sensory examination were normal. There is not any evidence of significant vascular impairment in the affected extremities. Brain MRI and CT scan and cervical MRI were normal. During 2 days of admission, with intravenous hydration, heparin 5000 unit SC q12hr and physical therapy of the affected limbs, motor and sensory function improved and was normal except mild paresthesia. He was discharged 1 day later for outpatient follow up while vitamin B1 100mg orally was prescribed.Paresthesia improved after 3 days without further sequels. PMID:25650360

  2. Lightning strike-induced brachial plexopathy

    PubMed Central

    Bhargava, Amita N.; Kasundra, Gaurav M.; Khichar, Subhakaran; Bhushan, Bharat S. K.

    2014-01-01

    We describe a patient who presented with a history of lightning strike injury. Following the injury, he sustained acute right upper limb weakness with pain. Clinically, the lesion was located to the upper and middle trunk of the right brachial plexus, and the same confirmed with electrophysiological studies. Nerve damage due to lightning injuries is considered very rare, and a plexus damage has been described infrequently, if ever. Thus, the proposed hypothesis that lightning rarely causes neuropathy, as against high-voltage electric current, due to its shorter duration of exposure not causing severe burns which lead to nerve damage, needs to be reconsidered. PMID:25288846

  3. Neurological complications of prolonged hunger strike.

    PubMed

    Başoğlu, M; Yetimalar, Y; Gürgör, N; Büyükçatalbaş, S; Kurt, T; Seçil, Y; Yeniocak, A

    2006-10-01

    We investigated neurological findings in 41 prisoners (mean age: 28.6) who participated in a hunger strike between 2000 and 2002. All cases were evaluated using neuropsychological, neuroradiological, and electrophysiological methods. The total duration of fasting ranged from 130 to 324 days (mean 199 days). All cases had 200-600 mg/day thiamine orally for 60-294 days (mean 156) during the hunger strike, and had neurological findings consistent with Wernicke-Korsakoff syndrome. All 41 patients exhibited altered consciousness which lasted from 3 to 31 days. All patients also presented gaze-evoked horizontal nystagmus and truncal ataxia. Paralysis of lateral rectus muscles was found in 14. Amnesia was apparent in all cases. Abnormal nerve conduction study parameters were not found in the patient group, but the amplitude of compound muscle action potential of the median and fibular nerves and sensory nerve action potential amplitude of the sural nerve were lower than the control group, and distal motor latency of the posterior tibial nerve was significantly prolonged as compared with the control group. The latency of visual evoked potential was prolonged in 22 cases. Somatosensory evoked potential (P37) was prolonged but not statistically significant. Our most significant finding was that the effect of hunger was more prominent on the central nervous system than on the neuromuscular system, despite the fact that all patients were taking thiamine. In our opinion, partial recovery of neurological, and neurocognitive signs in prolonged hunger could be a result of permanent neurological injury. PMID:16987161

  4. Millimeter-accuracy GPS landslide monitoring using Precise Point Positioning with Single Receiver Phase Ambiguity (PPP-SRPA) resolution: a case study in Puerto Rico

    NASA Astrophysics Data System (ADS)

    Wang, G. Q.

    2013-03-01

    Continuous Global Positioning System (GPS) monitoring is essential for establishing the rate and pattern of superficial movements of landslides. This study demonstrates a technique which uses a stand-alone GPS station to conduct millimeter-accuracy landslide monitoring. The Precise Point Positioning with Single Receiver Phase Ambiguity (PPP-SRPA) resolution employed by the GIPSY/OASIS software package (V6.1.2) was applied in this study. Two-years of continuous GPS data collected at a creeping landslide were used to evaluate the accuracy of the PPP-SRPA solutions. The criterion for accuracy was the root-mean-square (RMS) of residuals of the PPP-SRPA solutions with respect to "true" landslide displacements over the two-year period. RMS is often regarded as repeatability or precision in GPS literature. However, when contrasted with a known "true" position or displacement it could be termed RMS accuracy or simply accuracy. This study indicated that the PPP-SRPA resolution can provide an accuracy of 2 to 3 mm horizontally and 8 mm vertically for 24-hour sessions with few outliers (< 1%) in the Puerto Rico region. Horizontal accuracy below 5 mm can be stably achieved with 4-hour or longer sessions if avoiding the collection of data during extreme weather conditions. Vertical accuracy below 10 mm can be achieved with 8-hour or longer sessions. This study indicates that the PPP-SRPA resolution is competitive with the conventional carrier-phase double-difference network resolution for static (longer than 4 hours) landslide monitoring while maintaining many advantages. It is evident that the PPP-SRPA method would become an attractive alternative to the conventional carrier-phase double-difference method for landslide monitoring, notably in remote areas or developing countries.

  5. 20 CFR 345.402 - Strikes or work stoppages.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Strikes or work stoppages. 345.402 Section... INSURANCE ACT EMPLOYERS' CONTRIBUTIONS AND CONTRIBUTION REPORTS Benefit Charging § 345.402 Strikes or work stoppages. If benefits are payable to an employee for days of unemployment resulting from a strike or...

  6. 20 CFR 345.402 - Strikes or work stoppages.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... INSURANCE ACT EMPLOYERS' CONTRIBUTIONS AND CONTRIBUTION REPORTS Benefit Charging § 345.402 Strikes or work stoppages. If benefits are payable to an employee for days of unemployment resulting from a strike or work... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Strikes or work stoppages. 345.402...

  7. 20 CFR 345.402 - Strikes or work stoppages.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Strikes or work stoppages. 345.402 Section... INSURANCE ACT EMPLOYERS' CONTRIBUTIONS AND CONTRIBUTION REPORTS Benefit Charging § 345.402 Strikes or work stoppages. If benefits are payable to an employee for days of unemployment resulting from a strike or...

  8. 20 CFR 345.402 - Strikes or work stoppages.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Strikes or work stoppages. 345.402 Section 345... INSURANCE ACT EMPLOYERS' CONTRIBUTIONS AND CONTRIBUTION REPORTS Benefit Charging § 345.402 Strikes or work stoppages. If benefits are payable to an employee for days of unemployment resulting from a strike or...

  9. 20 CFR 345.402 - Strikes or work stoppages.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Strikes or work stoppages. 345.402 Section 345... INSURANCE ACT EMPLOYERS' CONTRIBUTIONS AND CONTRIBUTION REPORTS Benefit Charging § 345.402 Strikes or work stoppages. If benefits are payable to an employee for days of unemployment resulting from a strike or...

  10. Late Cretaceous through Cenozoic strike-slip tectonics of southwestern Alaska

    USGS Publications Warehouse

    Miller, M.L.; Bradley, D.C.; Bundtzen, T.K.; McClelland, W.

    2002-01-01

    New geologic mapping and geochronology show that margin-parallel strike-slip faults on the western limb of the southern Alaska orocline have experienced multiple episodes of dextral motion since ~100 Ma. These faults are on the upper plate of a subduction zone ~350-450 km inboard of the paleotrench. In southwestern Alaska, dextral displacement is 134 km on the Denali fault, at least 88-94 km on the Iditarod-Nixon Fork fault, and perhaps tens of kilometers on the Dishna River fault. The strike-slip regime coincided with Late Cretaceous sedimentation and then folding in the Kuskokwim basin, and with episodes of magmatism and mineralization at ~70, ~60, and ~30 Ma. No single driving mechanism can explain all of the ~95 million-year history of strike-slip faulting. Since ~40 Ma, the observed dextral sense of strike slip has run contrary to the sense of subduction obliquity. This may be explained by northward motion of the Pacific plate driving continental margin slivers into and/or around the oroclinal bend. From 44 to 66 Ma, oroclinal rotation, perhaps involving large-scale flexural slip, may have been accompanied by westward escape of crustal blocks along strike-slip faults. However, reconstructions of this period involve unproven assumptions about the identity of the subducting plate, the position of subducting ridges, and the exact timing of oroclinal bending, thus obscuring the driving mechanisms of strike slip. Prior to 66 Ma, oblique subduction is the most plausible driving mechanism for dextral strike slip. Cumulative displacement on all faults of the western limb of the orocline is at least 400 km, about half that on the eastern limb; this discrepancy might be explained by a combination of thrusting and unrecognized strike-slip faulting.

  11. A bird strike handbook for base-level managers

    NASA Astrophysics Data System (ADS)

    Payson, R. P.; Vance, J. D.

    1984-09-01

    To help develop more awareness about bird strikes and bird strike reduction techniques, this thesis compiled all relevant information through an extensive literature search, review of base-level documents, and personal interviews. The final product--A Bird Strike Handbook for Base-Level Managers--provides information on bird strike statistics, methods to reduce the strike hazards, and means to obtain additional assistance. The handbook is organized for use by six major base agencies: Maintenance, Civil Engineering, Operations, Air Field Management, Safety, and Air Traffic Control. An appendix follows at the end.

  12. Ability of photovoltaic modules to withstand lightning strikes

    NASA Astrophysics Data System (ADS)

    Felder, B.; Robb, J. D.

    The ability of glass superstrate and metal/plastic substrate modules to withstand lightning strikes was examined. Each of three different types of modules were exposed to four nearby and one direct strike of high voltage, long arc simulated lightning, and to one direct strike of high current, long duration lightning. Visual and electrical examination demonstrated that the high voltage strikes produced no electrical damage to the glass superstrate modules and little to the plastic substrate module. The high current, long duration strike resulted in varying degrees of physical damage to all modules but little or no loss in electrical performance.

  13. The Distribution of Cloud to Ground Lightning Strike Intensities and Associated Magnetic Inductance Fields Near the Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Burns, Lee; Decker, Ryan

    2005-01-01

    Lightning strike location and peak current are monitored operationally in the Kennedy Space Center (KSC) Cape Canaveral Air Force Station (CCAFS) area by the Cloud to Ground Lightning Surveillance System (CGLSS). The present study compiles ten years worth of CGLSS data into a database of near strikes. Using shuffle launch platform LP39A as a convenient central point, all strikes recorded within a 20-mile radius for the period of record O R ) from January 1, 1993 to December 31,2002 were included in the subset database. Histograms and cumulative probability curves are produced for both strike intensity (peak current, in kA) and the corresponding magnetic inductance fields (in A/m). Results for the full POR have application to launch operations lightning monitoring and post-strike test procedures.

  14. Lightning strikes to a NASA airplane penetrating thunderstorms at low altitudes

    NASA Technical Reports Server (NTRS)

    Mazur, V.; Fisher, B. D.; Gerlach, J. C.

    1986-01-01

    The NASA Storm Hazards program was dedicated during the 1984 storm season to a study of lightning strikes on an instrumented F-106B aircraft, during penetrations of thunderstorms at altitudes lower than the 6-8 km center of lightning flash density. These altitudes coincide with the negative charge region of thunderstorms. An analysis of the correlation between the UHF band radar data obtained and TV images of lightning strikes indicates that, with a known aircraft position relative to the radar, the lightning channel motion can be adequately interpreted on the basis of radar echo evolution.

  15. Displacements and segment linkage in strike-slip fault zones

    NASA Astrophysics Data System (ADS)

    Peacock, D. C. P.

    Small-scale, well exposed strike-slip fault zones near Kirkcudbright, Scotland, cut sub-vertical bedding, so that mapped bed separations allow the displacements, linkage and evolution of fault segments to be assessed. Displacement variations along the segments can be related to lithologic variations, conjugate relationships, offsets, segment linkage and fault bends. High displacement gradients at the tips of conjugate and offset faults produce convex-upwards ( E-type) displacement-distance ( d-x) profiles. Contractional fault bends and linkage points are marked by a decrease in fault displacement, producing partially concave-upwards ( D-type) d-x profiles. Where fault displacement gradients are steep, wallrocks are marked by structures such as synthetic faults, normal drag folding, ductile strain and veining, which transfer displacement. The faults studied tend to have lower r/ dMAX ratios (where r = distance between the point of maximum displacement and the fault tip on a particular profile, and dMAX = maximum displacement on the profile) than are shown by normal faults in map view. This may be because r is measured parallel to the displacement direction and/or because of lithologic variations.

  16. Impact on ART initiation of point-of-care CD4 testing at HIV diagnosis among HIV-positive youth in Khayelitsha, South Africa

    PubMed Central

    Patten, Gabriela EM; Wilkinson, Lynne; Conradie, Karien; Isaakidis, Petros; Harries, Anthony D; Edginton, Mary E; De Azevedo, Virginia; van Cutsem, Gilles

    2013-01-01

    Introduction Despite the rapid expansion of antiretroviral therapy (ART) programmes in developing countries, pre-treatment losses from care remain a challenge to improving access to treatment. Youth and adolescents have been identified as a particularly vulnerable group, at greater risk of loss from both pre-ART and ART care. Point-of-care (POC) CD4 testing has shown promising results in improving linkage to ART care. In Khayelitsha township, South Africa, POC CD4 testing was implemented at a clinic designated for youth aged 12–25 years. We assessed whether there was an associated reduction in attrition between HIV testing, assessment for eligibility and ART initiation. Methods A before-and-after observational study was conducted using routinely collected data. These were collected on patients from May 2010 to April 2011 (Group A) when baseline CD4 count testing was performed in a laboratory and results were returned to the clinic within two weeks. Same-day POC CD4 testing was implemented in June 2011, and data were collected on patients from August 2011 to July 2012 (Group B). Results A total of 272 and 304 youth tested HIV-positive in Group A and Group B, respectively. Group B patients were twice as likely to have their ART eligibility assessed compared to Group A patients: 275 (90%) vs. 183 (67%) [relative risk (RR)=2.4, 95% CI: 1.8–3.4, p<0.0001]. More patients in World Health Organization (WHO) Stage 1 disease (85% vs. 69%), with CD4 counts≥350 cells/µL (58% vs. 35%) and more males (13% vs. 7%) were detected in Group B. The proportion of eligible patients who initiated ART was 50% and 44% (p=0.6) in Groups B and A, respectively; and 50% and 43% (p=0.5) when restricted to patients with baseline CD4 count≤250 cells/µL. Time between HIV-testing and ART initiation was reduced from 36 to 28 days (p=0.6). Discussion POC CD4 testing significantly improved assessment for ART eligibility. The improvement in the proportion initiating ART and the reduction in

  17. Children on hunger strike: child abuse or legitimate protest?

    PubMed

    Mok, A; Nelson, E A; Murphy, J; Hampson, A; Hendriks, J H

    1996-02-24

    The issue of children on hunger strike (voluntary total fasting) has not been reported before. The World Medical Association Declaration of Tokyo 1975 and the Declaration of Malta 1991 (revised 1992) provide clinicians with guidelines for the management of adult patients on hunger strike but do not mention children. We report the management of 14 Vietnamese children, aged 1 to 12 years, who took part in a hunger strike at a refugee detention centre in Hong Kong. PMID:8597690

  18. THE EFFECT OF HAND DOMINANCE ON MARTIAL ARTS STRIKES

    PubMed Central

    Neto, Osmar Pinto; Silva, Jansen Henrique; de Miranda Marzullo, Ana Carolina; Bolander, Richard P.; Bir, Cynthia A.

    2011-01-01

    The main goal of this study was to compare dominant and non-dominant martial arts palm strikes under different circumstances that usually happen during martial arts and combative sports applications. Seven highly experienced (10 ± 5 years) right hand dominant Kung Fu practitioners performed strikes with both hands, stances with left or right lead legs, and with the possibility or not of stepping towards the target (moving stance). Peak force was greater for the dominant hand strikes (1593.76 ± 703.45 N vs. 1042.28 ± 374.16 N; p < .001), whereas no difference was found in accuracy between the hands (p = .141). Additionally, peak force was greater for the strikes with moving stance (1448.75 ± 686.01 N vs. 1201.80 ± 547.98 N; p = .002) and left lead leg stance (1378.06 ± 705.48 N vs.1269.96 ± 547.08 N). Furthermore, the difference in peak force between strikes with moving and stationary stances was statistically significant only for the strikes performed with a left lead leg stance (p = .007). Hand speed was higher for the dominant hand strikes (5.82 ± 1.08 m/s vs. 5.24 ± 0.78 m/s; p = 0.001) and for the strikes with moving stance (5.79 ± 1.01 m/s vs. 5.29 ± 0.90 m/s; p < .001). The difference in hand speed between right and left hand strikes was only significant for strikes with moving stance. In summary, our results suggest that the stronger palm strike for a right-handed practitioner is a right hand strike on a left lead leg stance moving towards the target. PMID:22047701

  19. The 1983 direct strike lightning data, part 1

    NASA Technical Reports Server (NTRS)

    Thomas, Mitchel E.

    1985-01-01

    Data waveforms are presented which were obtained during the 1983 direct strike lightning tests utilizing the NASA F106-B aircraft specially instrumented for lightning electromagnetic measurements. The aircraft was operated in the vicinity of the NASA Langley Research Center, Hampton, Virginia, in a thunderstorm environment to elicit strikes. Electromagnetic field data and conduction currents on the aircraft were recorded for attached lightning. Part 1 contains 435 pages of lightning strike data in chart form.

  20. A decade of U.S. Air Force bat strikes

    USGS Publications Warehouse

    Peurach, Suzanne C.; Dove, Carla J.; Stepko, Laura

    2009-01-01

    From 1997 through 2007, 821 bat strikes were reported to the U.S. Air Force (USAF) Safety Center by aircraft personnel or ground crew and sent to the National Museum of Natural History, Smithsonian Institution, for identification. Many samples were identified by macroscopic and or microscopic comparisons with bat specimens housed in the museum and augmented during the last 2 years by DNA analysis. Bat remains from USAF strikes during this period were received at the museum from 40 states in the United States and from 20 countries. We confirmed that 46% of the strikes were caused by bats, but we did not identify them further; we identified 5% only to the family or genus level, and 49% to the species level. Fifty-five of the 101 bat-strike samples submitted for DNA analysis have been identified to the species level. Twenty-five bat species have been recorded striking USAF planes worldwide. The Brazilian free-tailed bat (Tadarida brasiliensis; n = 173) is the species most commonly identified in USAF strike impacts, followed by the red bat (Lasiurus borealis; n = 83). Bat strikes peak during the spring and fall, with >57% occurring from August through October; 82% of the reports that included time of strike were recorded between 2100 and 0900 hours. More than 12% of the bat strikes were reported at >300 m above ground level (AGL). Although <1% of the bat-strike reports indicated damage to USAF aircraft, cumulative damage for 1997 through 2007 totaled >$825,000 and >50% of this sum was attributable to 5 bat-strike incidents. Only 5 bats from the 10 most damaging bat strikes were identified to the species level, either because we did not receive remains with the reports or the sample was insufficient for identification.

  1. "Thunderstruck": penetrating thoracic injury from lightning strike.

    PubMed

    van Waes, Oscar J F; van de Woestijne, Pieter C; Halm, Jens A

    2014-04-01

    Lightning strike victims are rarely presented at an emergency department. Burns are often the primary focus. This case report describes the improvised explosive device like-injury to the thorax due to lightning strike and its treatment, which has not been described prior in (kerauno)medicine. Penetrating injury due to blast from lightning strike is extremely rare. These "shrapnel" injuries should however be ruled out in all patients struck by lightning. PMID:24054789

  2. Strong Algerian Earthquake Strikes Near Capital City

    NASA Astrophysics Data System (ADS)

    Ayadi, A.; Maouche, S.; Harbi, A.; Meghraoui, M.; Beldjoudi, H.; Oussadou, F.; Mahsas, A.; Benouar, D.; Heddar, A.; Rouchiche, Y.; Kherroubi, A.; Frogneux, M.; Lammali, K.; Benhamouda, F.; Sebaï, A.; Bourouis, S.; Alasset, P. J.; Aoudia, A.; Cakir, Z.; Merahi, M.; Nouar, O.; Yelles, A.; Bellik, A.; Briole, P.; Charade, O.; Thouvenot, F.; Semane, F.; Ferkoul, A.; Deramchi, A.; Haned, S. A.

    On 21 May 2003, a damaging earthquake of Mw 6.8 struck the region of Boumerdes 40 km east of Algiers in northern Algeria (Figure 1). The mainshock, which lasted ~ 36-40 s, had devastating effects and claimed about 2300 victims, caused more than 11,450 injuries, and left about 200,000 people homeless. It destroyed and seriously damaged around 180,000 housing units and 6000 public buildings with losses estimated at $5 billion. The mainshock was widely felt within a radius of ~ 400 km in Algeria. To the north, the earthquake was felt in southeastern Spain, including the Balearic Islands, and also in Sardinia and in southern France. The mainshock location, which was calculated at 36.91°N, 3.58°E (15 km offshore of Zemmouri; Figure 1), and the local magnitude (Md 6.4) are from seismic records of local stations. International seismological centers obtained Mw 6.8 (NEIC) with a thrust focal mechanism solution and 1.83 × 1026 dyne.cm for the seismic moment. A sequence of aftershocks affected the epicentral area with two strong shocks reaching Mw 5.8 on 27 and 29 May 2003. Field investigations allowed us to assign a maximum intensity X (European Macroseismic Scale 98) and to report rockfalls, minor surface cracks, and liquefaction phenomena. The mainshock was not associated with inland surface faulting, but one of the most striking coseismic effects is the coastal uplift and the backwash along the littoral of the Mitidja basin.

  3. [Hunger striking in prisons: ethics and the ethical and legal aspects].

    PubMed

    García-Guerrero, J

    2013-01-01

    Hunger strike is a common form of protest in prisons and is a potential cause of many types of problems, both for the prison administration and the doctors who care for prisoners who participate in one. Issues of conflict of rights and obligations involved, and how to treat people who are subject to the Administration, which in this case takes the position of guarantor, have created major controversies over doctrine. Conscientious objection and the conflict of dual loyalty of doctors working in prisons are also issues closely linked to a prison hunger strike. In this paper we review the solution given to the problem of treatment of a prison hunger strike from three perspectives: ethics, ethical and legal. PMID:23529363

  4. Manifestations of Strike-Slip Faulting on Ganymede

    NASA Technical Reports Server (NTRS)

    DeRemer, Lindsay C.; Pappalardo, Robert T.

    2003-01-01

    Voyager images of Ganymede suggested that strike-slip faulting may have taken place [1, 2], but the role of this process in shaping grooved terrain was uncertain. In Galileo high-resolution images of Ganymede's surface, we recognize three signature features of strike-slip faulting: (1) en echelon structures, (2) strike-slip duplexes, and (3) offset preexisting features. We have undertaken a study to recognize and map these features, and identify any morphological progressions of strike-slip features. This will allow a better understanding of the structural history of Ganymede, and the formation and evolution of grooved terrain.

  5. Debunking the viper's strike: harmless snakes kill a common assumption.

    PubMed

    Penning, David A; Sawvel, Baxter; Moon, Brad R

    2016-03-01

    To survive, organisms must avoid predation and acquire nutrients and energy. Sensory systems must correctly differentiate between potential predators and prey, and elicit behaviours that adjust distances accordingly. For snakes, strikes can serve both purposes. Vipers are thought to have the fastest strikes among snakes. However, strike performance has been measured in very few species, especially non-vipers. We measured defensive strike performance in harmless Texas ratsnakes and two species of vipers, western cottonmouths and western diamond-backed rattlesnakes, using high-speed video recordings. We show that ratsnake strike performance matches or exceeds that of vipers. In contrast with the literature over the past century, vipers do not represent the pinnacle of strike performance in snakes. Both harmless and venomous snakes can strike with very high accelerations that have two key consequences: the accelerations exceed values that can cause loss of consciousness in other animals, such as the accelerations experienced by jet pilots during extreme manoeuvres, and they make the strikes faster than the sensory and motor responses of mammalian prey and predators. Both harmless and venomous snakes can strike faster than the blink of an eye and often reach a target before it can move. PMID:26979562

  6. Risk factors associated with participation in the Ontario, Canada doctors' strike.

    PubMed

    Kravitz, R L; Shapiro, M F; Linn, L S; Froelicher, E S

    1989-09-01

    To identify factors associated with participation in the 1986 Ontario, Canada doctors' strike, we surveyed 1,028 physicians; 69 percent responded, of whom 42 percent participated in the strike. Risk factors for participation included income greater than $135,000, being a surgeon or gynecologist, having previously "opted out" of the Ontario Health Insurance Plan, being professionally dissatisfied, being politically conservative, favoring political activism by physicians, holding a positive view of the social consequences of extrabilling, and perceiving family, associates, patients and the public to favor the strike. Eighty percent of strikers, but 32 percent of non-strikers, met criteria we established for four strike-prone groups: the "economically rational," the "ideologically committed," the "professionally disaffected," and the "socially malleable." Respondents belonging to one or more of these groups were much more likely to have participated in the strike (64 percent vs 17 percent). Strategies to deal with physician militancy should address the multiplicity of motives that appeared to have influenced doctors in Ontario. PMID:2764198

  7. Global strike-slip fault distribution on Enceladus reveals mostly left-lateral faults

    NASA Astrophysics Data System (ADS)

    Martin, E. S.; Kattenhorn, S. A.

    2013-12-01

    Within the outer solar system, normal faults are a dominant tectonic feature; however, strike-slip faults have played a role in modifying the surfaces of many icy bodies, including Europa, Ganymede, and Enceladus. Large-scale tectonic deformation in icy shells develops in response to stresses caused by a range of mechanisms including polar wander, despinning, volume changes, orbital recession/decay, diurnal tides, and nonsynchronous rotation (NSR). Icy shells often preserve this record of tectonic deformation as patterns of fractures that can be used to identify the source of stress responsible for creating the patterns. Previously published work on Jupiter's moon Europa found that right-lateral strike-slip faults predominantly formed in the southern hemisphere and left-lateral strike-slip faults in the northern hemisphere. This pattern suggested they were formed in the past by stresses induced by diurnal tidal forcing, and were then rotated into their current longitudinal positions by NSR. We mapped the distribution of strike-slip faults on Enceladus and used kinematic indicators, including tailcracks and en echelon fractures, to determine their sense of slip. Tailcracks are secondary fractures that form as a result of concentrations of stress at the tips of slipping faults with geometric patterns dictated by the slip sense. A total of 31 strike-slip faults were identified, nine of which were right-lateral faults, all distributed in a seemingly random pattern across Enceladus's surface, in contrast to Europa. Additionally, there is a dearth of strike-slip faults within the tectonized terrains centered at 90°W and within the polar regions north and south of 60°N and 60°S, respectively. The lack of strike-slip faults in the north polar region may be explained, in part, by limited data coverage. The south polar terrain (SPT), characterized by the prominent tiger stripes and south polar dichotomy, yielded no discrete strike-slip faults. This does not suggest that

  8. Four strikes against physical mapping of DNA.

    PubMed

    Goldberg, P W; Golumbic, M C; Kaplan, H; Shamir, R

    1995-01-01

    Physical mapping is a central problem in molecular biology and the human genome project. The problem is to reconstruct the relative position of fragments of DNA along the genome from information on their pairwise overlaps. We show that four simplified models of the problem lead to NP-complete decision problems: Colored unit interval graph completion, the maximum interval (or unit interval) subgraph, the pathwidth of a bipartite graph, and the k-consecutive ones problem for k > or = 2. These models have been chosen to reflect various features typical in biological data, including false-negative and positive errors, small width of the map, and chimericism. PMID:7497116

  9. 14 CFR 25.631 - Bird strike damage.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Bird strike damage. 25.631 Section 25.631... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.631 Bird strike damage. The... airplane after impact with an 8-pound bird when the velocity of the airplane (relative to the bird...

  10. 14 CFR 25.631 - Bird strike damage.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Bird strike damage. 25.631 Section 25.631... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.631 Bird strike damage. The... airplane after impact with an 8-pound bird when the velocity of the airplane (relative to the bird...

  11. 14 CFR 25.631 - Bird strike damage.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Bird strike damage. 25.631 Section 25.631... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.631 Bird strike damage. The... airplane after impact with an 8-pound bird when the velocity of the airplane (relative to the bird...

  12. Gratifications Lost: The 1985 Philadelphia Newspaper Strike and Media Use.

    ERIC Educational Resources Information Center

    Elliott, William R.; Rosenberg, William L.

    A study examined the relationship between newspaper gratifications sought and media use during and after a 1985 strike by unions of two Philadelphia newspapers, and the compensatory media behaviors, if any, people adopted to make up for the loss of their daily newspaper(s). It was hypothesized that during the strike, people would read more…

  13. 14 CFR 25.631 - Bird strike damage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Bird strike damage. 25.631 Section 25.631... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.631 Bird strike damage. The... airplane after impact with an 8-pound bird when the velocity of the airplane (relative to the bird...

  14. 14 CFR 25.631 - Bird strike damage.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bird strike damage. 25.631 Section 25.631... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.631 Bird strike damage. The... airplane after impact with an 8-pound bird when the velocity of the airplane (relative to the bird...

  15. Using Grids to Teach the Skill of Striking

    ERIC Educational Resources Information Center

    Horton, Mel L.

    2006-01-01

    This article discusses the grid system as a strategy for enhancing the skill of striking in physical education. A grid system is a box or rectangle-defined space in which students practice specific skills or strategies in pairs or small groups. Here, the author provides sample activities that can be used with grids to teach striking skills for…

  16. Strikes, Arbitration, and Teacher Salaries: A Behavioral Analysis.

    ERIC Educational Resources Information Center

    Delaney, John Thomas

    1983-01-01

    Using a behavioral theory of bargaining, the authors examined data sets from Illinois and Iowa school districts and from a national sample of teachers. Results suggest that strike use and the availability of arbitration and the right to strike affect teacher salaries, while arbitration use does not. (Author/SK)

  17. Risk Considerations of Bird Strikes to Space Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Hales, Christy; Ring, Robert

    2016-01-01

    Within seconds after liftoff of the Space Shuttle during mission STS-114, a turkey vulture impacted the vehicle's external tank. The contact caused no apparent damage to the Shuttle, but the incident led NASA to consider the potential consequences of bird strikes during a Shuttle launch. The environment at Kennedy Space Center provides unique bird strike challenges due to the Merritt Island National Wildlife Refuge and the Atlantic Flyway bird migration routes. NASA is currently refining risk assessment estimates for the probability of bird strike to space launch vehicles. This paper presents an approach for analyzing the risks of bird strikes to space launch vehicles and presents an example. The migration routes, types of birds present, altitudes of those birds, exposed area of the launch vehicle, and its capability to withstand impacts affect the risk due to bird strike. A summary of significant risk contributors is discussed.

  18. Positive psychotherapy.

    PubMed

    Seligman, Martin E P; Rashid, Tayyab; Parks, Acacia C

    2006-11-01

    Positive psychotherapy (PPT) contrasts with standard interventions for depression by increasing positive emotion, engagement, and meaning rather than directly targeting depressive symptoms. The authors have tested the effects of these interventions in a variety of settings. In informal student and clinical settings, people not uncommonly reported them to be "life-changing." Delivered on the Web, positive psychology exercises relieved depressive symptoms for at least 6 months compared with placebo interventions, the effects of which lasted less than a week. In severe depression, the effects of these Web exercises were particularly striking. This address reports two preliminary studies: In the first, PPT delivered to groups significantly decreased levels of mild-to-moderate depression through 1-year follow-up. In the second, PPT delivered to individuals produced higher remission rates than did treatment as usual and treatment as usual plus medication among outpatients with major depressive disorder. Together, these studies suggest that treatments for depression may usefully be supplemented by exercises that explicitly increase positive emotion, engagement, and meaning. ((c) 2006 APA, all rights reserved). PMID:17115810

  19. The predatory strike of free ranging praying mantises, Sphodromantis lineola (Burmeister). II: Strikes in the horizontal plane.

    PubMed

    Cleal, K S; Prete, F R

    1996-01-01

    The predatory behavior of free ranging praying mantises, Sphodromantis lineola (Burmeister), in response to prey at various positions in the horizontal plane was examined using high speed (200 frames per second) videography. We found that the movements of the meso- and metathoracic legs over the course of the strike were analogous in many respects to those made by the cockroach Periplaneta americana during escape turns. When mantises struck at prey directly ahead of them, they were propelled forward by extensions of the metathoracic femur-tibia, and the meso- and metathoracic coxa-femur joints (changes in the latter were determined indirectly via changes in the femur-pterothorax angles). This pattern of movements is similar to that of cockroach Type 1 turns. However, when prey lay to either side of the pterothorax-abdomen axis, mantises turned toward the prey as they stuck. These turning movements were the result, primarily, of changes in the femur-thorax angles. Specifically, as the mantises turned toward the prey, contralateral mesothoracic femora and metathoracic tibiae and femora extended, and the corresponding ipsilateral joints extended to a lesser degree or flexed. This pattern of movements is similar to that of cockroach Type 2 turns. In addition, these leg movements were accompanied by flexion of the prothorax-abdomen angle which turned the prothorax even further in the direction of the prey. We found a stronger relationship between mantis leg movements and the position of the prey in relationship to the pterothorax than between the leg movements and the position of the prey in the visual field. Our data suggest that the praying mantis' central nervous system integrates proprioceptive and visual information in order to determine the location of prey in "pterothorax-centered' rather than "head-centered' space. PMID:8886390

  20. Strikes by physicians: a historical perspective toward an ethical evaluation.

    PubMed

    Thompson, Stephen L; Salmon, J Warren

    2006-01-01

    Current conditions surrounding the house of medicine-including corporate and government cost-containment strategies, increasing market-penetration schemes in health care, along with clinical scrutiny and the administrative control imposed under privatization by managed care firms, insurance companies, and governments-have spurred an upsurge in physician unionization, which requires a revisiting of the issue of physician strikes. Strikes by physicians have been relatively rare events in medical history. When they have occurred, they have aroused intense debate over their ethical justification among professionals and the public alike, notwithstanding what caused the strikes. As physicians and other health care providers increasingly find employment within organizations as wage-contract employees and their work becomes more highly rationalized, more physicians will join labor organizations to protect both their economic and their professional interests. As a result, these physicians will have to come to terms with the use of the strike weapon. On the surface, many health care strikes may not ever seem justifiable, but in certain defined situations a strike would be not only permissible but an ethical imperative. With an exacerbation of labor strife in the health sector in many nations, it is crucial to explore the question of what constitutes an ethical physician strike. PMID:16878396

  1. [Physicians' strikes and health services: an ethical perspective].

    PubMed

    Goić, A

    1996-07-01

    For the public opinion, medical strikes are a controversial issue; physician's ethical judgments are also different. The present article analyses the requisites to consider legitimate a strike and, based on these, the ethical duties of physicians; the features of medical unionism; the ethical duties of authority; the manipulation of ill people by the strike and the social factors that may cause these conflicts. In a medical strike, universal ethical values based on the Hyppocratic oath and promoted by the profession, are endangered. This article concludes that a medical strike may be explainable due to different reasons, but it is not ethically justifiable beyond any doubt. The health profession that is not prepared to give up strikes as gremial pressure tool, should not choose a profession that takes care of the ill. The best way to avoid medical strike is to prevent them: the society and the authority have the ethical obligation to create work conditions that elude conflicts. To settle disputes between physicians and health institutions, the creation of a permanent arbitral instance agreed by physicians and the authority, i.e. a high level committee integrated by respected individuals and physicians, could be necessary. This committee should send forth veredicts that would be obeyed by the contending parties. PMID:9138378

  2. Local avian density influences risk of mortality from window strikes.

    PubMed

    Sabo, Ann M; Hagemeyer, Natasha D G; Lahey, Ally S; Walters, Eric L

    2016-01-01

    Up to a billion birds die per year in North America as a result of striking windows. Both transparent and reflective glass panes are a cause for concern, misleading birds by either acting as invisible, impenetrable barriers to desired resources, or reflecting those resources over a large surface area. A high number of window strikes occur during migration, but little is known about the factors of susceptibility, or whether particular avian taxa are more vulnerable than others. We report on a study of window strikes and mist-netting data at the Virginia Zoological Park (Norfolk, Virginia, USA), conducted in the autumn of 2013 and 2014. We focused on three factors likely to contribute to an individual's predisposition to collide with windows: (i) taxonomic classification, (ii) age, and (iii) migrant vs. resident status. Thrushes, dominated by the partial migrant American Robin (Turdus migratorius), were significantly less likely to strike glass than be sampled in mist nets (χ(2) = 9.21, p = 0.002), while wood-warblers (Parulidae) were more likely to strike than expected (χ(2) = 13.55, p < 0.001). The proportion of juveniles striking windows (45.4%) was not significantly different (χ(2) = 0.05, p = 0.827) than the population of juvenile birds naturally occurring at the zoo (48.8%). Migrants, however, were significantly more susceptible to window strikes than residents (χ(2) = 6.35, p = 0.012). Our results suggest that resident birds are able to learn to avoid and thus reduce their likelihood of striking windows; this intrinsic risk factor may help explain the apparent susceptibility of certain taxa to window strikes. PMID:27366656

  3. Local avian density influences risk of mortality from window strikes

    PubMed Central

    Sabo, Ann M.; Hagemeyer, Natasha D.G.; Lahey, Ally S.

    2016-01-01

    Up to a billion birds die per year in North America as a result of striking windows. Both transparent and reflective glass panes are a cause for concern, misleading birds by either acting as invisible, impenetrable barriers to desired resources, or reflecting those resources over a large surface area. A high number of window strikes occur during migration, but little is known about the factors of susceptibility, or whether particular avian taxa are more vulnerable than others. We report on a study of window strikes and mist-netting data at the Virginia Zoological Park (Norfolk, Virginia, USA), conducted in the autumn of 2013 and 2014. We focused on three factors likely to contribute to an individual’s predisposition to collide with windows: (i) taxonomic classification, (ii) age, and (iii) migrant vs. resident status. Thrushes, dominated by the partial migrant American Robin (Turdus migratorius), were significantly less likely to strike glass than be sampled in mist nets (χ2 = 9.21, p = 0.002), while wood-warblers (Parulidae) were more likely to strike than expected (χ2 = 13.55, p < 0.001). The proportion of juveniles striking windows (45.4%) was not significantly different (χ2 = 0.05, p = 0.827) than the population of juvenile birds naturally occurring at the zoo (48.8%). Migrants, however, were significantly more susceptible to window strikes than residents (χ2 = 6.35, p = 0.012). Our results suggest that resident birds are able to learn to avoid and thus reduce their likelihood of striking windows; this intrinsic risk factor may help explain the apparent susceptibility of certain taxa to window strikes. PMID:27366656

  4. Physicians' strikes and the competing bases of physicians' moral obligations.

    PubMed

    MacDougall, D Robert

    2013-09-01

    Many authors have addressed the morality of physicians' strikes on the assumption that medical practice is morally different from other kinds of occupations. This article analyzes three prominent theoretical accounts that attempt to ground such special moral obligations for physicians--practice-based accounts, utilitarian accounts, and social contract accounts--and assesses their applicability to the problem of the morality of strikes. After critiquing these views, it offers a fourth view grounding special moral obligations in voluntary commitments, and explains why this is a preferable basis for understanding physicians' moral obligations in general and especially as pertaining to strikes. PMID:24199524

  5. Exhumation and continental strike-slip fault systems: Introduction

    USGS Publications Warehouse

    Roeske, S.M.; Till, A.B.; Foster, D.A.; Sample, J.C.

    2007-01-01

    Metamorphic rocks adjacent to and within strike-slip faultsystems occur in a wide range of tectonic settings. Detailed studies show that for a number of these locales a significant part of the exhumation occurred during strike-slip fault motion, but the specific processes involved are often cryptic. Although some sites share characteristic features, such as metamorphic rocks exhumed in extensional step-overs within overall transtensional systems, no one common theme emerges from all of the studies. Our understanding of the variables that control continental strike-slip faults' interaction with mid- to lower-crustal structures is still primitive.

  6. San Andreas-sized Strike-slip Fault on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    opens the fault and subsequent tidal stress causes it to move lengthwise in one direction. Then tidal forces close the fault again, preventing the area from moving back to its original position. Daily tidal cycles produce a steady accumulation of lengthwise offset motions. Here on Earth, unlike Europa, large strike-slip faults like the San Andreas are set in motion by plate tectonic forces.

    North is to the top of the picture and the sun illuminates the surface from the top. The image, centered at 66 degrees south latitude and 195 degrees west longitude, covers an area approximately 300 by 203 kilometers(185 by 125 miles). The pictures were taken on September 26, 1998by Galileo's solid-state imaging system.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  7. Positive Changes in Perceptions and Selections of Healthful Foods by College Students after a Short-Term Point-of-Selection Intervention at a Dining Hall

    ERIC Educational Resources Information Center

    Peterson, Sharon; Duncan, Diana Poovey; Null, Dawn Bloyd; Roth, Sara Long; Gill, Lynn

    2010-01-01

    Objective: Determine the effects of a short-term, multi-faceted, point-of-selection intervention on college students' perceptions and selection of 10 targeted healthful foods in a university dining hall and changes in their self-reported overall eating behaviors. Participants: 104 college students, (age 18-23) completed pre-I and post-I surveys.…

  8. Electromiographic and kinematic characteristics of Kung Fu Yau-Man palm strike.

    PubMed

    Neto, O P; Magini, Marcio

    2008-12-01

    A kinematic and electromyographic analysis of Kung Fu (KF) Yau-Man palm strikes without impact is presented. An empirical model applied to data obtained by a high-speed camera describes the kinematic characteristics of the movement. The electromyographic patterns of the biceps brachii, brachioradialis and triceps brachii muscles were studied during the strike in the time (root mean square) and frequency (wavelet transform) domains. Eight KF practitioners participated in the investigation. A wooden board was placed in front of the subjects, and they were asked to perform the strike imagining a target above the board. The results show that the Yau-Man KF palm strike has very similar kinematic characteristics to a simple moderate speed elbow extension movement. All practitioners positioned themselves in relation to the wooden board in a way to achieve their highest hand speeds in the instant their hands crossed the board. The analyses of the electromyography data shows a well developed muscle coordination of the practitioners in agreement with kinematic results. The results of this paper are important not only for improving the performance of practitioners but also to demonstrate the applicability of KF in the process of motor control development. PMID:17499517

  9. Concussions Strike 1 in 3 Water Polo Players

    MedlinePlus

    ... fullstory_159634.html Concussions Strike 1 in 3 Water Polo Players Average was just over 2 per ... 2016 WEDNESDAY, June 29, 2016 (HealthDay News) -- Add water polo to the list of sports where concussions ...

  10. Pathognomonic symptom associated with lightning strike: Lichtenberg figure.

    PubMed

    Yigit, Mehmet; Tanrikulu, Nazmiye; Turkdogan, Kenan Ahmet; Yigit, Eda

    2015-02-01

    Lightning strikes especially occur during spring and summer months in the afternoons when there is heavy rain. In deaths resulting from lightning strike, there may either be no evidence on the dead person's clothes or body, or there may be burnt or torn patches on their clothes and lichtenberg figures specific to lightning strikes on their bodies. In such cases that also have a comorbid of cognitive dysfunction, since there is generally amnesia, having these figures during the physical examination has a valuable place in early diagnosis and quick treatment. This paper presents a case of lightning strike that was found to have Lichtenberg figures on the back and right leg after secondary examination. PMID:25842563

  11. Striking nurses and midwives stand united against Hunt's pay freeze.

    PubMed

    Keogh, Kat; Kleebauer, Alistair

    2014-10-21

    Thousands of nurses and midwives in England and Northern Ireland went on strike in protest at the government's decision to deny 70 per cent of NHS nurses a 1 per cent cost of living pay rise. PMID:25315523

  12. Measurements of lightning rod responses to nearby strikes

    NASA Astrophysics Data System (ADS)

    Moore, C. B.; Aulich, G. D.; Rison, W.

    2000-05-01

    Following Benjamin Franklin's invention of the lightning rod, based on his discovery that electrified objects could be discharged by approaching them with a metal needle in hand, conventional lightning rods in the U.S. have had sharp tips. In recent years, the role of the sharp tip in causing a lightning rod to act as a strike receptor has been questioned leading to experiments in which pairs of various sharp-tipped and blunt rods have been exposed beneath thunderclouds to determine the better strike receptor. After seven years of tests, none of the sharp Franklin rods or of the so-called “early streamer emitters” has been struck, but 12 blunt rods with tip diameters ranging from 12.7 mm to 25.4 mm have taken strikes. Our field experiments and our analyses indicate that the strike-reception probabilities of Franklin's rods are greatly increased when their tips are made moderately blunt.

  13. Inferential Model Criticism of the "Empire Strikes Back."

    ERIC Educational Resources Information Center

    Frentz, Thomas F.; Hale, Mary E.

    1983-01-01

    Describes a method of rhetorical criticism to be used in situations where the values of critic and audience differ in significant ways. Uses the method to analyze the responses of children to "The Empire Strikes Back." (PD)

  14. Why You Can Expect Fewer Teacher Strikes This Year

    ERIC Educational Resources Information Center

    American School Board Journal, 1975

    1975-01-01

    The National Education Association and the American Federation of Teachers are facing three realities that might make them reluctant to strike: an army of unemployed teachers, an internecine battle, and a rotten economy. (Author/IRT)

  15. Depression Strikes, Stays with Many Caregivers of Critically Ill

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_158780.html Depression Strikes, Stays With Many Caregivers of Critically Ill ... News) -- Caregivers for the critically ill often suffer depression that lingers long after their loved one's hospital ...

  16. 33. SOUTH, PIER IV, DRAW REST SUPPORT, END LOCK STRIKE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. SOUTH, PIER IV, DRAW REST SUPPORT, END LOCK STRIKE AND JACK PAD. OPEN END OF SHORE BOX. - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

  17. Concussions Strike 1 in 3 Water Polo Players

    MedlinePlus

    ... medlineplus.gov/news/fullstory_159634.html Concussions Strike 1 in 3 Water Polo Players Average was just ... are common. A recent survey of more than 1,500 USA Water Polo members found 36 percent ...

  18. Cancer Strikes Out!/Definitions/ Glossary/ Common Types

    MedlinePlus

    ... Cover Story: Leukemia/Lymphoma Cancer Strikes Out!/ Definitions/ Glossary/ Common Types Past Issues / Summer 2008 Table of ... stage and the type of cancer. Leukemia-Lymphoma Glossary B-cell: A white blood cell that comes ...

  19. Position and velocity sensitivities at the triangular libration points in the restricted problem of three bodies when the bigger primary is an oblate body

    NASA Astrophysics Data System (ADS)

    Hassan, M. R.; Antia, H. M.; Bhatnagar, K. B.

    2013-07-01

    In this paper we have examined the stability of triangular libration points in the restricted problem of three bodies when the bigger primary is an oblate spheroid. Here we followed the time limit and computational process of Tuckness (Celest. Mech. Dyn. Mech. 61, 1-19, 1995) on the stability criteria given by McKenzie and Szebehely (Celest. Mech. 23, 223-229, 1981). In this study it was found that in comparison to other studies the value of the critical mass μ c has been reduced due to oblateness of the bigger primary, i.e. the range of stability of the equilateral triangular libration points reduced with the increase of the oblateness parameter I and hence the order of commensurability was increased.

  20. Enhanced resistive switching phenomena using low-positive-voltage format and self-compliance IrOx/GdOx/W cross-point memories

    PubMed Central

    2014-01-01

    Enhanced resistive switching phenomena of IrOx/GdOx/W cross-point memory devices have been observed as compared to the via-hole devices. The as-deposited Gd2O3 films with a thickness of approximately 15 nm show polycrystalline that is observed using high-resolution transmission electron microscope. Via-hole memory device shows bipolar resistive switching phenomena with a large formation voltage of -6.4 V and high operation current of >1 mA, while the cross-point memory device shows also bipolar resistive switching with low-voltage format of +2 V and self-compliance operation current of <300 μA. Switching mechanism is based on the formation and rupture of conducting filament at the IrOx/GdOx interface, owing to oxygen ion migration. The oxygen-rich GdOx layer formation at the IrOx/GdOx interface will also help control the resistive switching characteristics. This cross-point memory device has also Repeatable 100 DC switching cycles, narrow distribution of LRS/HRS, excellent pulse endurance of >10,000 in every cycle, and good data retention of >104 s. This memory device has great potential for future nanoscale high-density non-volatile memory applications. PMID:24400888

  1. Optimization of stability index versus first strike cost

    SciTech Connect

    Canavan, G.H.

    1997-05-01

    This note studies the impact of maximizing the stability index rather than minimizing the first strike cost in choosing offensive missile allocations. It does so in the context of a model in which exchanges between vulnerable missile forces are modeled probabilistically, converted into first and second strike costs through approximations to the value target sets at risk, and the stability index is taken to be their ratio. The value of the allocation that minimizes the first strike cost for both attack preferences are derived analytically. The former recovers results derived earlier. The latter leads to an optimum at unity allocation for which the stability index is determined analytically. For values of the attack preference greater than about unity, maximizing the stability index increases the cost of striking first 10--15%. For smaller values of the attack preference, maximizing the index increases the second strike cost a similar amount. Both are stabilizing, so if both sides could be trusted to target on missiles in order to minimize damage to value and maximize stability, the stability index for vulnerable missiles could be increased by about 15%. However, that would increase the cost to the first striker by about 15%. It is unclear why--having decided to strike--he would do so in a way that would increase damage to himself.

  2. The influence of striking object characteristics on the impact energy.

    PubMed

    Sprenger, Florian D; Siegenthaler, Lea; Kneubuehl, Beat P; Jackowski, Christian

    2016-05-01

    A common form of violence investigated in legal medicine is blunt trauma caused by striking with different objects. The injuries and medical consequences have been widely examined, whereas the forces and especially the energies acting on impact have rarely been analyzed. This study focuses on how the impact energy of different striking objects depends on their characteristics. A total of 1170 measurements of horizontal strikes against a static and relatively heavy pendulum have been acquired with 13 volunteers. The main focus was laid on how the weight, the length, and the center of mass of the different striking objects influenced the striking energy. The results show average impact energies in the range of 67.3 up to 311.5 J for men with an optimum weight of about 1.3 kg with its center of mass in the far end quarter for a 1-m-long striking object. The average values for women range from 30 to 202.6 J, with an optimum weight between 1.65 and 2.2 kg and similar settings for the center of mass as the men. Also, the impact energies are getting higher with shorter object lengths and reach a maximum at a length of about 0.3 to 0.4 m. The male volunteers' impact energy was on average by 84.2% higher than the values of the female volunteers, where the impact masses were very similar and the impact velocities played the key role. PMID:26449359

  3. Application of converted-wave amplitude for fracture strike delineation - a physical model study

    NASA Astrophysics Data System (ADS)

    Chang, Chih-Hsiung; Chang, Young-Fo Chang; Tseng, Po-Yen; Lin, Chao-Ming

    2013-04-01

    The objective of this study is aiming on directing the fracture strike in a vertically aligned fracture reservoir using the seismic signature of the azimuthal dependence of C-wave amplitude (ADCA). A fractured reservoir has made itself as one of the most important productive zones in petroleum exploration. The existence of fractures not just provides the space for the residence of oils and gases but creates pathways for migration. In terms of seismic anisotropy, reservoirs that possess vertical fractures system (VFS) has its physical properties vary in azimuth and is often grouped as a horizontally transversely isotropy (HTI). Since fracture strike is the priori information in drilling engineering that has to be known to maximize production or to enhance oil recovery (EOR) from a VFS reservoir. Therefore, characterizing a fractured reservoir and orienting the fracture strike has attracted much attention by exploration geophysicists and drilling engineers. To validate our objective, a HTI model was designed to simulate a VFS reservoir. A spherical dome was caved at one side of the HTI model. In laboratory, a pair of S-type transducer was used to carry out our reflection experiments. And constant offset reflections were acquired along principal symmetry directions and diagonal direction of the HTI model at two different offset intervals. In all, two constant offset reflection data sets were obtained and each data set consists of three observations collected at different azimuths. In the acquired seismic profile, a mixture of P-wave, S-wave and C-wave events were recognized. In analyzing the variation of C-wave amplitude in azimuth in the HTI model, reflections that were originated from apex of the dome structure were sorted and displayed as a common-reflection-point (CRP) gather. Our laboratory data show C-wave amplitude decrease with azimuth varying from a strike direction toward a direction transverse to the strike in the HTI model. The phenomenon of ADCA that was

  4. Simulation and measurement of melting effects on metal sheets caused by direct lightning strikes

    NASA Technical Reports Server (NTRS)

    Kern, Alexander

    1991-01-01

    Direct lightning strikes melt metal parts of various systems, like fuel and propellant tanks of rockets and airplanes, at the point of strike. Responsible for this melting are the impulse current and, if occurring, the long duration current, both carrying a remarkable charge Q. For studying these meltings the simulation in the laboratory has to be based on the parameters of natural lightnings. International standards exist defining certain threat levels of natural lightnings and giving possible generator circuits for the simulation. The melting caused by both types of lightning currents show different appearance. Their characteristics, their differences in melting and heating of metal sheets are investigated. Nevertheless the simulation of lightning in the laboratory is imperfect. While natural lightning is a discharge without a counter electrode, the simulation always demands a close counter electrode. The influence of this counter electrode is studied.

  5. A three-dimensional viscoelastic model of a strike slip fault

    NASA Technical Reports Server (NTRS)

    Rundle, J. B.; Jackson, D. D.

    1975-01-01

    An analytic approximation to the Green's function for the displacements due to a strike slip point source in an elastic layer over a viscoelastic half-space is developed. This approximate Green's function is useful because it can be analytically integrated over the fault surface. Comparison with a numerical integration of the exact solution integral indicates that the approximation is quite good. The approximate Green's function is integrated analytically to obtain the displacements due to a finite rectangular strike slip fault in an elastic layer over a viscoelastic half-space. Ground displacements and angle changes from a model survey net are computed to illustrate the viscoelastic relaxation which follows a fracture in the elastic region.

  6. Numerical Assessment of the Diagnostic Capabilities of the Instrumented Calorimeter for SPIDER (STRIKE)

    SciTech Connect

    Dalla Palma, M.; Pasqualotto, R.; Rizzolo, A.; Serianni, G.; Veltri, P.; De Muri, M.

    2011-09-26

    An important feature of the ITER project is represented by additional heating via injection of neutral beams from accelerated negative ions. To study and optimise their production, the SPIDER test facility is under construction in Padova, with the aim of testing beam characteristics and to verify the source proper operation.STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment) is a diagnostic to characterise the SPIDER negative ion beam during short operation (several seconds). During long pulse operations, STRIKE is parked off-beam in the vacuum vessel. The most important measurements are beam uniformity, beamlet divergence and stripping losses. STRIKE is directly exposed to the beam and is formed of 16 tiles, one for each beamlet groups. The measurements are provided by thermal cameras, current sensors, thermocouples and electrostatic sensors. This paper presents the investigation of the influence on the response of STRIKE of: thermal characteristics of the tile material, exposure angle, features of some dedicated diagnostics. The uniformity of the beam will be studied by measurements of the current flowing through each tile and by thermal cameras. Simulations show that it will be possible to verify experimentally whether the beam meets the ITER requirement about the maximum allowed beam non-uniformity (below {+-}10%). In the simulations also the influence of the beam halo has been included; the effect of off-perveance conditions has been studied. To estimate the beamlet divergence, STRIKE can be moved along the beam direction at two different distances from the accelerator. The optimal positions have been defined taking into account design constraints. The effect of stripping on the comparison between currents and heat loads has been assessed; this will allow to obtain an experimental estimate of stripping. Electrostatic simulations have provided the suitable tile biasing voltage in order to reabsorb secondary particles into the same tile as the

  7. Volcano instability induced by strike-slip faulting

    NASA Astrophysics Data System (ADS)

    Lagmay, A. M. F.; van Wyk de Vries, B.; Kerle, N.; Pyle, D. M.

    2000-09-01

    Analogue sand cone experiments were conducted to study instability generated on volcanic cones by basal strike-slip movement. The results of the analogue models demonstrate that edifice instability may be generated when strike-slip faults underlying a volcano move as a result of tectonic adjustment. This instability occurs on flanks of the volcano above the strike-slip shear. On the surface of the volcano this appears as a pair of sigmoids composed of one reverse and one normal fault. In the interior of the cone the faults form a flower structure. Two destabilised regions are created on the cone flanks between the traces of the sigmoidal faults. Bulging, intense fracturing and landsliding characterise these unstable flanks. Additional analogue experiments conducted to model magmatic intrusion show that fractures and faults developed within the volcanic cone due to basal strike-slip motions strongly control the path of the intruding magma. Intrusion is diverted towards the areas where previous development of reverse and normal faults have occurred, thus causing further instability. We compare our model results to two examples of volcanoes on strike-slip faults: Iriga volcano (Philippines), which underwent non-magmatic collapse, and Mount St. Helens (USA), where a cryptodome was emplaced prior to failure. In the analogue and natural examples, the direction of collapse takes place roughly parallel to the orientation of the underlying shear. The model presented proposes one mechanism for strike-parallel breaching of volcanoes, recently recognised as a common failure direction of volcanoes found in regions with transcurrent and transtensional deformation. The recognition of the effect of basal shearing on volcano stability enables prediction of the likely direction of eventual flank failure in volcanoes overlying strike-slip faults.

  8. A Flexure-Based Tool Holder for Sub-(micro)m Positioning of a Single Point Cutting Tool on a Four-axis Lathe

    SciTech Connect

    Bono, M J; Hibbard, R L

    2005-12-05

    A tool holder was designed to facilitate the machining of precision meso-scale components with complex three-dimensional shapes with sub-{micro}m accuracy on a four-axis lathe. A four-axis lathe incorporates a rotary table that allows the cutting tool to swivel with respect to the workpiece to enable the machining of complex workpiece forms, and accurately machining complex meso-scale parts often requires that the cutting tool be aligned precisely along the axis of rotation of the rotary table. The tool holder designed in this study has greatly simplified the process of setting the tool in the correct location with sub-{micro}m precision. The tool holder adjusts the tool position using flexures that were designed using finite element analyses. Two flexures adjust the lateral position of the tool to align the center of the nose of the tool with the axis of rotation of the B-axis, and another flexure adjusts the height of the tool. The flexures are driven by manual micrometer adjusters, each of which provides a minimum increment of motion of 20 nm. This tool holder has simplified the process of setting a tool with sub-{micro}m accuracy, and it has significantly reduced the time required to set a tool.

  9. Reconciling Invariant Topography with Significant Along-Strike Gradients in Climate and Tectonics in the Greater Caucasus

    NASA Astrophysics Data System (ADS)

    Forte, A. M.; Whipple, K. X.; Bookhagen, B.; Rossi, M. W.

    2015-12-01

    The Greater Caucasus mountains (GC), which represent the locus of NE-SW directed convergence in the central Arabia-Eurasia collision, are an E-W striking orogen characterized by significant gradients in climate and tectonics. West of 45ºE the GC are a singly-sided, south-directed orogen with a low modern shortening rate of 1-4 mm/yr and a high mean annual precipitation (MAP) of 1-2 m/yr. Contrastingly, east of 45ºE, the GC are doubly-vergent, underlain by a subducting slab, shortening at 8-12 mm/yr and have a MAP of 0.1-0.5 m/yr. Despite these significant gradients, the topography of the GC is remarkably similar along-strike, suggesting (1) an eastward increase in erosion rate to balance the shortening gradient, (2) a westward increase in uplift rate to balance the MAP gradient, or (3) similar uplift and erosion rates along-strike independent of the MAP and shortening gradients. We utilize established relationships between catchment scale erosion rates and topography (hillslope gradients and channel steepness) developed elsewhere to assess whether an along-strike gradient in erosion rates is likely in the GC. We combine this with an analysis of the modern GC climate from satellite (TRMM and MODIS) and river discharge data. The relationship between channel steepness and mean hillslope gradient is invariant along-strike. Precipitation variability is positively correlated with elevation and constant along-strike, but runoff variability is low throughout the range and does not vary systematically along-strike. Together these results suggest no significant gradient in erosional efficiency along-strike. Invariant topography and erosional efficiency along-strike could imply similar uplift and erosion rates along-strike, but ultimately require quantitative measures of both to confirm. If erosion and uplift rates are similar along-strike, this requires an additional mechanism to explain the invariant topography despite the strong gradient in modern shortening rate.

  10. Isolated Sensorineural Hearing Loss as a Sequela after Lightning Strike.

    PubMed

    Turan, Mahfuz; Kalkan, Ferhat; Bozan, Nazım; Özçalimli, İsa; Zeki Erdem, Mehmet; Yalınkılıç, Abdülaziz; Garca, Mehmet Fatih

    2015-01-01

    In most of the surviving patients after a lightning strike, audiovestibular abnormalities have been reported. The most frequently reported type of abnormalities is a tympanic membrane perforation with hearing loss and external ear canal burn. However a sensor neural hearing loss and mixed type hearing loss can also occur, but these occur rarely. A nineteen-year-old female patient had, after a lightning strike, serious burns on the left ear, behind the ear, and on the chest and neck. She also had in her left ear 108 dB hearing loss with irregular central perforation and in her right ear 52 dB sensorineural hearing loss. There was no hearing loss before the strike. A hearing aid was recommended for the right ear and good care and follow-up were recommended for the left ear. A lightning strike can cause serious audiological damage. Therefore, it is necessary to make a careful audiovestibular evaluation of the patients. Although there exist rarely healed cases from sensorineural hearing loss after lightning strike in literature, in our case hearing loss occurred bilaterally and then it healed unilaterally. This condition is quite rare in literature. PMID:26161278

  11. How Orogen-scale Exhumed Strike-slip Faults Initiate

    NASA Astrophysics Data System (ADS)

    Cao, S.; Neubauer, F.

    2015-12-01

    Orogen-scale strike-slip faults present one the most important geodynamic processes affecting the lithosphere-asthenosphere system. In specific subtypes, faulting is virtually initiated along hot-to-cool boundaries, e.g. at such of hot granite intrusions or metamorphic core complexes to cool country rocks. Such fault zones are often subparallel to mountain ranges and expose a wide variety of mylonitic, cataclastic and non-cohesive fault rocks, which were formed at different structural levels of the crust and are stacked within each other ("telescoping"). Exhumation of rocks is, therefore, a common feature of such strike-slip faults implying major transtensive and/or transpressive processes accompanying pure strike-slip motion. The hot-to-cool thermal structure across the fault zone significantly influences the physical fault rock properties. One major question is how and where a major strike-slip initiates and further development. Here, we propose a model in which major continental exhumed strike-slip faults potentially evolve along rheologically weak zones such as plutons or margins of metamorphic complexes. As an example, we propose a model for the Ailao Shan-Red River (ASRR) fault, SE Asia, which initiated along the edge of a plutonic belt and evolved in response to India-Asia collision with four tectonic phases.

  12. Is There Evidence to Support a Forefoot Strike Pattern in Barefoot Runners? A Review

    PubMed Central

    Lorenz, Daniel S.; Pontillo, Marisa

    2012-01-01

    Context: Barefoot running is a trend among running enthusiasts that is the subject of much controversy. At this time, benefits appear to be more speculative and anecdotal than evidence based. Additionally, the risk of injuries is not well established. Evidence acquisition: A PubMed search was undertaken for articles published in English from 1980 to 2011. Additional references were accrued from reference lists of research articles. Results: While minimal data exist that definitively support barefoot running, there are data lending support to the argument that runners should use a forefoot strike pattern in lieu of a heel strike pattern to reduce ground reaction forces, ground contact time, and step length. Conclusions: Whether there is a positive or negative effect on injury has yet to be determined. Unquestionably, more research is needed before definitive conclusions can be drawn. PMID:24179586

  13. A Preclinical Model for ERα-Positive Breast Cancer Points to the Epithelial Microenvironment as Determinant of Luminal Phenotype and Hormone Response.

    PubMed

    Sflomos, George; Dormoy, Valerian; Metsalu, Tauno; Jeitziner, Rachel; Battista, Laura; Scabia, Valentina; Raffoul, Wassim; Delaloye, Jean-Francois; Treboux, Assya; Fiche, Maryse; Vilo, Jaak; Ayyanan, Ayyakkannu; Brisken, Cathrin

    2016-03-14

    Seventy-five percent of breast cancers are estrogen receptor α positive (ER⁺). Research on these tumors is hampered by lack of adequate in vivo models; cell line xenografts require non-physiological hormone supplements, and patient-derived xenografts (PDXs) are hard to establish. We show that the traditional grafting of ER⁺ tumor cells into mammary fat pads induces TGFβ/SLUG signaling and basal differentiation when they require low SLUG levels to grow in vivo. Grafting into the milk ducts suppresses SLUG; ER⁺ tumor cells develop, like their clinical counterparts, in the presence of physiological hormone levels. Intraductal ER⁺ PDXs are retransplantable, predictive, and appear genomically stable. The model provides opportunities for translational research and the study of physiologically relevant hormone action in breast carcinogenesis. PMID:26947176

  14. Real-time attitude commanding to detect coverage gaps and generate high resolution point clouds for RSO shape characterization with a laser rangefinder

    NASA Astrophysics Data System (ADS)

    Nayak, M.; Beck, J.; Udrea, B.

    This paper expands on previous studies by the authors into 3D imaging with a single-beam laser rangefinder (LRF) by implementing real-time attitude maneuvers of a chaser satellite flying in relative orbit around a resident space object (RSO). Point clouds generated with an LRF are much sparser than those generated with an imaging LIDAR, making it difficult to autonomously distinguish between gaps in coverage and truly empty space. Furthermore, if both the attitude and the shape of the target RSO are unknown, it is particularly difficult to register a collection of LRF strike points together and detect gaps in strike point coverage in realtime. This paper presents the incorporation of a narrow field of-view (NFOV) camera that detects the strike point on the RSO and supplements LRF distance measurements with image data. This data is used to generate attitude command profiles that efficiently fill LRF coverage gaps and generate high density point clouds, thus maximizing coverage of an unknown RSO. Results obtained so far point the way to a real-time implementation of the algorithm. A method to detect and close gaps in LRF strike point coverage is presented first. Coverage gap detection is achieved using Voronoi diagrams, where Voronoi cells are centered at the LRF strike points. A three-part algorithm is used that 1) creates a 3D panoramic map from “ stitched” NFOV camera images; 2) correlates the areas of sparse LRF coverage to the map; and 3) generates attitude commands to close the coverage gaps. The map provides a consistent and reliable method to register positions of strike points relative to each other and to the NFOV image of the RSO without a priori knowledge of the RSO attitude. Using this algorithm, gaps and sparse areas in LRF coverage are covered with strike points, allowing for the generation of a higher-resolution point cloud than that obtained with preprogrammed attitude profiles. Attitude maneuvers can now be designed on-line in real-ti- e such

  15. After the strike: using facilitation in a residency training program.

    PubMed

    Andres, D; Hamoline, D; Sanders, M; Anderson, J

    1998-03-10

    Methods of alternative dispute resolution, including facilitation, can be used to identify and resolve areas of conflict. Facilitation was used by the University of Saskatchewan's Department of Family Medicine (Saskatoon division) after the strike by residents in July and August 1995 so as to allow optimal use of the remaining educational time. Through facilitation, experiences of the strike and areas of potential conflict were explored. Participants had a broad range of responses to the strike. Specific coping strategies were developed to deal with identified concerns. Although outcomes were not measured formally, levels of trust improved and collegial relationships were restored. Because so many changes occur in health care and medical education, conflict inevitably arises. Facilitation offers one way of dealing with change constructively, thereby making possible the optimal use of educational time. PMID:9526479

  16. Structure as a causal factor in nurses' strikes.

    PubMed

    Hibberd, J M

    1988-01-01

    Nurses employed in Alberta's hospitals have earned a reputation of militancy as a result of four province-wide strikes in the 11-year period 1977-1988. Based on a case study of the first three strikes, the principal causes of the labour disputes are discussed: namely, union ideology, economic factors and inherent constraints in the structure of bargaining in the public sector. Interorganizational relationships of the three main players, the United Nurses of Alberta, the Alberta Hospital Association and the provincial government have been contributing factors in all three strikes. Although issues in the disputes were primarily economic, demands associated with the needs of working women, and demands that threatened the traditional prerogatives of management were at the heart of every impasse. PMID:10290776

  17. Comparison of Blade-Strike Modeling Results with Empirical Data

    SciTech Connect

    Carlson, Thomas J.; Ploskey, Gene R.

    2004-05-06

    This study is the initial stage of further investigation into the dynamics of injury to fish during passage through a turbine runner. As part of the study, Pacific Northwest National Laboratory (PNNL) estimated the probability of blade strike, and associated injury, as a function of fish length and turbine operating geometry at two adjacent turbines in Powerhouse 1 of Bonneville Dam. Units 5 and 6 had identical intakes, stay vanes, wicket gates, and draft tubes, but Unit 6 had a new runner and curved discharge ring to minimize gaps between the runner hub and blades and between the blade tips and discharge ring. We used a mathematical model to predict blade strike associated with two Kaplan turbines and compared results with empirical data from biological tests conducted in 1999 and 2000. Blade-strike models take into consideration the geometry of the turbine blades and discharges as well as fish length, orientation, and distribution along the runner.

  18. Improved setup and positioning accuracy using a three-point customized cushion/mask/bite-block immobilization system for stereotactic reirradiation of head and neck cancer.

    PubMed

    Wang, He; Wang, Congjun; Tung, Samuel; Dimmitt, Andrew Wilson; Wong, Pei Fong; Edson, Mark A; Garden, Adam S; Rosenthal, David I; Fuller, Clifton D; Gunn, Gary B; Takiar, Vinita; Wang, Xin A; Luo, Dershan; Yang, James N; Wong, Jennifer; Phan, Jack

    2016-01-01

    The purpose of this study was to investigate the setup and positioning uncertainty of a custom cushion/mask/bite-block (CMB) immobilization system and determine PTV margin for image-guided head and neck stereotactic ablative radiotherapy (HN-SABR). We analyzed 105 treatment sessions among 21 patients treated with HN-SABR for recurrent head and neck cancers using a custom CMB immobilization system. Initial patient setup was performed using the ExacTrac infrared (IR) tracking system and initial setup errors were based on comparison of ExacTrac IR tracking system to corrected online ExacTrac X-rays images registered to treatment plans. Residual setup errors were determined using repeat verification X-ray. The online ExacTrac corrections were compared to cone-beam CT (CBCT) before treatment to assess agreement. Intrafractional positioning errors were determined using prebeam X-rays. The systematic and random errors were analyzed. The initial translational setup errors were -0.8 ± 1.3 mm, -0.8 ± 1.6 mm, and 0.3 ± 1.9 mm in AP, CC, and LR directions, respectively, with a three-dimensional (3D) vector of 2.7 ± 1.4 mm. The initial rotational errors were up to 2.4° if 6D couch is not available. CBCT agreed with ExacTrac X-ray images to within 2 mm and 2.5°. The intrafractional uncertainties were 0.1 ± 0.6 mm, 0.1 ± 0.6 mm, and 0.2 ± 0.5 mm in AP, CC, and LR directions, respectively, and 0.0° ± 0.5°, 0.0° ± 0.6°, and -0.1° ± 0.4° in yaw, roll, and pitch direction, respectively. The translational vector was 0.9 ± 0.6 mm. The calculated PTV margins mPTV(90,95) were within 1.6 mm when using image guidance for online setup correction. The use of image guidance for online setup correction, in combination with our customized CMB device, highly restricted target motion during treatments and provided robust immobilization to ensure minimum dose of 95% to target volume with 2.0 mm PTV margin for HN-SABR. PMID:27167275

  19. Comparison of blade-strike modeling results with empirical data

    SciTech Connect

    Ploskey, Gene R.; Carlson, Thomas J.

    2004-03-01

    This study is the initial stage of further investigation into the dynamics of injury to fish during passage through a turbine runner. As part of the study, Pacific Northwest National Laboratory (PNNL) estimated the probability of blade strike, and associated injury, as a function of fish length and turbine operating geometry at two adjacent turbines in Powerhouse 1 of Bonneville Dam. Units 5 and 6 had identical intakes, stay vanes, wicket gates, and draft tubes, but Unit 6 had a new runner and curved discharge ring to minimize gaps between the runner hub and blades and between the blade tips and discharge ring. We used a mathematical model to predict blade strike associated with two Kaplan turbines and compared results with empirical data from biological tests conducted in 1999 and 2000. Blade-strike models take into consideration the geometry of the turbine blades and discharges as well as fish length, orientation, and distribution along the runner. The first phase of this study included a sensitivity analysis to consider the effects of difference in geometry and operations between families of turbines on the strike probability response surface. The analysis revealed that the orientation of fish relative to the leading edge of a runner blade and the location that fish pass along the blade between the hub and blade tip are critical uncertainties in blade-strike models. Over a range of discharges, the average prediction of injury from blade strike was two to five times higher than average empirical estimates of visible injury from shear and mechanical devices. Empirical estimates of mortality may be better metrics for comparison to predicted injury rates than other injury measures for fish passing at mid-blade and blade-tip locations.

  20. Dynamic Ridges and Valleys in a Strike-Slip Environment

    NASA Astrophysics Data System (ADS)

    Duvall, Alison R.; Tucker, Gregory E.

    2015-10-01

    Strike-slip faults have long been known for characteristic near-fault landforms such as offset rivers and strike-parallel valleys. In this study, we use a landscape evolution model to investigate the longer-term, catchment-wide landscape response to horizontal fault motion. Our results show that strike-slip faulting induces a persistent state of disequilibrium in the modeled landscapes brought about by river lengthening along the fault alternating with abrupt shortening due to stream capture. The models also predict that, in some cases, ridges oriented perpendicular to the fault migrate laterally in conjunction with fault motion. We find that ridge migration happens when slip rate is slow enough and/or soil creep and river incision are efficient enough that the landscape can respond to the disequilibrium brought about by strike-slip motion. Regional rock uplift relative to baselevel also plays a role, as topographic relief is required for ridge migration. In models with faster horizontal slip rates, stronger rocks, or less efficient hillslope transport, ridge mobility is limited or arrested despite the continuance of river lengthening and capture. In these cases, prominent steep, fault-facing facets form along well-developed fault valleys. Comparison of landscapes adjacent to fast-slipping (>30 mm/yr) and slower-slipping (≤1 mm/yr or less) strike-slip faults in California, USA, reveals features that are consistent with model predictions. Our results highlight a potential suite of geomorphic signatures that can be used as indicators of horizontal crustal motion and geomorphic processes in strike-slip settings even after river capture has diminished or erased apparent offset along the fault.

  1. Inhibition of SA Node at Supine Position in Right Atrial Thrombus Complicating Behçet’s Disease – From Cardiac Surgical Point of View

    PubMed Central

    Hijazi, Emad Mohamed; Ibdah, Rasheed Khaled; Rawashdeh, Sukina Ismael; Saadeh, Abdullah Mahmoud; Al-Balas, Hamzeh Ibrahim

    2016-01-01

    Patient: Female, 27 Final Diagnosis: Right atrial thrombus compressing the sinoatrial node Symptoms: Dyspnea • cough and hemoptysis with supine bradycardia reaching 36/min and dizziness Medication: — Clinical Procedure: Cardiac surgical intervention removing the mechanical cause if conservative management failed can be done safely Specialty: Surgery Objective: Rare disease Background: Behçet’s disease (BD) is a chronic multi-systemic disease of unknown cause. Intra-cardiac thrombus (ICT) complicating BD is extremely rare. In general, cardiac manifestations in BD are associated with poor prognosis. Chest computed tomography (CT) scan and echocardiogram are excellent modalities for diagnosis and patient assessment. Cardiac surgical intervention can be done safely using an on-pump technique when medical management has failed. Case Report: We report on a case of a 27-year-old Jordanian woman diagnosed with BD who presented with dyspnea, cough, and hemoptysis, with supine bradycardia reaching 36 beats/minute and dizziness which disappear on sitting or standing position, and with heart rate reaching 76 beats/minute. Right atrial thrombus was identified using transthoracic echocardiogram and chest CT scan. After medical management failed, cardiac surgical intervention became an option and targeted extraction of the right atrial thrombus compressing the sinoatrial node (SA node). Conclusions: In BD, right atrial thrombus compressing the SA node is rare. If conservative management has failed, cardiac surgical intervention removing the mechanical cause can be done safely, either using on-pump with cross clamp or on-pump with beating heart technique. PMID:27311379

  2. Inhibition of SA Node at Supine Position in Right Atrial Thrombus Complicating Behçet's Disease - From Cardiac Surgical Point of View.

    PubMed

    Hijazi, Emad Mohamed; Ibdah, Rasheed Khaled; Rawashdeh, Sukina Ismael; Saadeh, Abdullah Mahmoud; Al-Balas, Hamzeh Ibrahim

    2016-01-01

    BACKGROUND Behçet's disease (BD) is a chronic multi-systemic disease of unknown cause. Intra-cardiac thrombus (ICT) complicating BD is extremely rare. In general, cardiac manifestations in BD are associated with poor prognosis. Chest computed tomography (CT) scan and echocardiogram are excellent modalities for diagnosis and patient assessment. Cardiac surgical intervention can be done safely using an on-pump technique when medical management has failed. CASE REPORT We report on a case of a 27-year-old Jordanian woman diagnosed with BD who presented with dyspnea, cough, and hemoptysis, with supine bradycardia reaching 36 beats/minute and dizziness which disappear on sitting or standing position, and with heart rate reaching 76 beats/minute. Right atrial thrombus was identified using transthoracic echocardiogram and chest CT scan. After medical management failed, cardiac surgical intervention became an option and targeted extraction of the right atrial thrombus compressing the sinoatrial node (SA node). CONCLUSIONS In BD, right atrial thrombus compressing the SA node is rare. If conservative management has failed, cardiac surgical intervention removing the mechanical cause can be done safely, either using on-pump with cross clamp or on-pump with beating heart technique. PMID:27311379

  3. The 1984 direct strike lightning data, part 1

    NASA Technical Reports Server (NTRS)

    Thomas, Mitchel E.; Carney, Harold K.

    1986-01-01

    Data waveforms are presented which were obtained during the 1984 direct-strike lightning tests utilizing the NASA F106-B aircraft specially instrumented for lightning electromagnetic measurements. The aircraft was operated in the vicinity of the NASA Langley Research Center, Hampton, Virginia, in a thunderstorm environment to elicit strikes. Electromagnetic field data and conduction currents on the aircraft were recorded for attached lightning. The entire transient recorder data obtained for 247 uses and 11 nearby flashes in the 1984 campaign are presented. This is part 1, consisting of summary and conclusion.

  4. A Cyclin T1 point mutation that abolishes positive transcription elongation factor (P-TEFb) binding to Hexim1 and HIV tat

    PubMed Central

    2014-01-01

    Background The positive transcription elongation factor b (P-TEFb) plays an essential role in activating HIV genome transcription. It is recruited to the HIV LTR promoter through an interaction between the Tat viral protein and its Cyclin T1 subunit. P-TEFb activity is inhibited by direct binding of its subunit Cyclin T (1 or 2) with Hexim (1 or 2), a cellular protein, bound to the 7SK small nuclear RNA. Hexim1 competes with Tat for P-TEFb binding. Results Mutations that impair human Cyclin T1/Hexim1 interaction were searched using systematic mutagenesis of these proteins coupled with a yeast two-hybrid screen for loss of protein interaction. Evolutionary conserved Hexim1 residues belonging to an unstructured peptide located N-terminal of the dimerization domain, were found to be critical for P-TEFb binding. Random mutagenesis of the N-terminal region of Cyclin T1 provided identification of single amino-acid mutations that impair Hexim1 binding in human cells. Furthermore, conservation of critical residues supported the existence of a functional Hexim1 homologue in nematodes. Conclusions Single Cyclin T1 amino-acid mutations that impair Hexim1 binding are located on a groove between the two cyclin folds and define a surface overlapping the HIV-1 Tat protein binding surface. One residue, Y175, in the centre of this groove was identified as essential for both Hexim1 and Tat binding to P-TEFb as well as for HIV transcription. PMID:24985203

  5. A Climatological Study of Cloud to Ground Lightning Strikes in the Vicinity of the Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Burns, Lee; Decker, Ryan

    2004-01-01

    Lightning strike location and peak current are monitored operationally in the Kennedy Space Center (KSC)/Cape Canaveral Air Force Station (CCAFS) area by the Cloud to Ground Lightning Surveillance System (CGLSS). The present study compiles ten years of CGLSS data into a climatological database of all strikes recorded within a 20-mile radius of space shuttle launch platform LP39A, which serves as a convenient central point. The period of record (POR) for the database runs from January 1, 1993 to December 31, 2002. Histograms and cumulative probability curves are produced to determine the distribution of occurrence rates for the spectrum of strike intensities (given in kA). Further analysis of the database provides a description of both seasonal and interannual variations in the lightning distribution.

  6. Kinematically Coupled Strike-Slip and Normal Faults in the Lake Mead Strike-Slip Fault System, Southeast Nevada

    NASA Astrophysics Data System (ADS)

    Kattenhorn, S. A.; Marshall, S. T.; Cooke, M. L.

    2008-12-01

    The Lake Mead fault system consists of a ~95 km long, northeast-trending zone of strike-slip faults of Miocene age that accommodate a total left-lateral offset of 20-65 km. We use a combination of detailed field mapping and numerical modeling to show that a previously unnamed left-lateral strike-slip segment of the Lake Mead fault system and a dense cluster of dominantly west-dipping normal faults acted in concert to accommodate regional left-lateral offset. We suggest that the strike-slip fault that we refer to as the Pinto Ridge fault: (1) was kinematically related to other faults of the Lake Mead fault system; (2) was responsible for the creation of the normal fault cluster at Pinto Ridge; and (3) utilized these normal faults as linking structures between separate strike-slip fault segments to create a longer, through-going fault. Results from numerical models demonstrate that the observed location and curving strike patterns of the normal fault cluster is consistent with the faults having formed as secondary structures as the result of the perturbed stress field around the slipping Pinto Ridge fault. Comparison of mechanical efficiency of various normal fault geometries within extending terranes suggests that the observed west dip of normal faults reflects a west- dipping anisotropy at depth, such as a detachment. The apparent terminations of numerous strike-slip faults of the Lake Mead fault system into west-dipping normal faults suggest that a west-dipping detachment may be regionally coherent.

  7. [A new method for the disruption of cell walls of gram-positive bacteria and mycobacteria on the point of nucleic acid extraction: sand method].

    PubMed

    Şahin, Fikret; Kıyan, Mehmet; Karasartova, Djursun; Çalgın, M Kerem; Akhter, Shameem; Türegün Atasoy, Buse

    2016-01-01

    Nowadays molecular methods are widely used in the rapid diagnosis of infectious agents. Polymerase chain reaction (PCR) is the most preferred method for this purpose. Obtaining sufficient and pure DNA or RNA is important for the PCR. Different DNA extraction protocols such as phenol-chloroform, proteinase K, glass beads and boiling have been used successfully for DNA isolation from gram-negative bacteria. However since gram-positive bacteria have a thicker layer of peptidoglycan and mycobacteria have complex glycolipids in their cell walls, for the isolation of DNA or RNA from these microorganisms, the complex cell wall structure must be eliminated. For this purpose, the bacterial cell wall must be completely or partially removed forming sferoblast using lysostaphin in the Staphylococcus genus as gram-positive bacteria and using a chemical like cetyltrimethyl ammonium bromide for the Mycobacterium genus. In this study, we planned to use sand particles for the mechanical elimination of the cell wall without any need for chemicals and we called this procedure as "sand method". For the purpose of DNA extraction, the fine-grained sand was washed with ddH(2)O without losing small particles and then sterilized by autoclaving. For the purpose of RNA extraction; the sand was washed with ddH(2)O, incubated for 30 minutes with 10% HCl, and then autoclaved. A methicillin-resistant Staphylococcus aureus (MRSA) strain previously isolated and identified from a clinical specimen was mixed in 100 µl Tris-EDTA buffer with 100 mg sand. The mixture of bacteria and sand was vortexed at the maximum speed for 5 minutes. The MRSA-sand mix was treated with proteinase K and phenol-chloroform, and ethanol precipitation protocol was then followed for obtaining DNA. For comparison of the sand method with the other methods, the same amount of bacteria used in the sand method was incubated for one hour with lysostaphin, and then the proteinase K DNA extraction method were completed in the same

  8. Torts Liability for Strike Action and Third Party Rights.

    ERIC Educational Resources Information Center

    Raday, Frances

    1979-01-01

    Studies the nature of the torts liability incurred in strikes and the extent of existing immunities bestowed on strikers and their organizers, and explores the principles that should govern liability and immunity. Available from Israel Law Review Association, c/o Faculty of Law, Hebrew University of Jerusalem, Mount Scopus, P.O.B. 24100, Jerusalem…

  9. Monte Carlo Simulation to Estimate Likelihood of Direct Lightning Strikes

    NASA Technical Reports Server (NTRS)

    Mata, Carlos; Medelius, Pedro

    2008-01-01

    A software tool has been designed to quantify the lightning exposure at launch sites of the stack at the pads under different configurations. In order to predict lightning strikes to generic structures, this model uses leaders whose origins (in the x-y plane) are obtained from a 2D random, normal distribution.

  10. Second, Unrelated Cancers Strike 1 in 12 Cancer Patients

    MedlinePlus

    ... medlineplus.gov/news/fullstory_159759.html Second, Unrelated Cancers Strike 1 in 12 Cancer Patients Unfortunately, they're often deadly To use ... in 12 -- already diagnosed with one form of cancer end up developing a second type of unrelated ...

  11. Lightning-Strike Disaster: Effects on Children's Fears and Worries.

    ERIC Educational Resources Information Center

    Dollinger, Stephen J.; And Others

    1984-01-01

    Compares fears of lightning-strike victims (N=29) with matched control children (N=58), using fear reports from children and their mothers. Differences between samples were most pronounced for child-reported fears. Correspondence between mothers' and children's reports of intense storm-related fears was markedly larger in the lightning sample than…

  12. Second, Unrelated Cancers Strike 1 in 12 Cancer Patients

    MedlinePlus

    ... gov/medlineplus/news/fullstory_159759.html Second, Unrelated Cancers Strike 1 in 12 Cancer Patients Unfortunately, they're often deadly To use ... in 12 -- already diagnosed with one form of cancer end up developing a second type of unrelated ...

  13. Suicidal protests: self-immolation, hunger strikes, or suicide bombing.

    PubMed

    Lester, David

    2014-08-01

    Following Lankford's persuasive argument that suicide bombers are indeed suicidal, the next question to ask is why individuals choose one form of suicidal protest over others. Why choose suicide bombing rather than a hunger strike or self-immolation? Some suggestions are provided. PMID:25162850

  14. Faculty Strikes in Higher Education: 1966-1994.

    ERIC Educational Resources Information Center

    Annunziato, Frank R.

    1994-01-01

    Over the 29-year period from 1966 to 1994, the number of faculty strikes recorded by the National Center for the Study of Collective Bargaining in Higher Education and the Professions totaled 163. They transpired in 96 two-year and 67 four-year institutions. The vast majority involved faculty members employed at public sector colleges and…

  15. Formation and Suppression of Strike-Slip Fault Systems

    NASA Astrophysics Data System (ADS)

    Curren, Ivy S.; Bird, Peter

    2014-11-01

    Strike-slip faults are a defining feature of plate tectonics, yet many aspects of their development and evolution remain unresolved. For intact materials and/or regions, a standard sequence of shear development is predicted from physical models and field studies, commencing with the formation of Riedel shears and culminating with the development of a throughgoing fault. However, for materials and/or regions that contain crustal heterogeneities (normal and/or thrust faults, joints, etc.) that predate shear deformation, kinematic evolution of strike-slip faulting is poorly constrained. We present a new plane-stress finite-strain physical analog model developed to investigate primary deformation zone evolution in simple shear, pure strike-slip fault systems in which faults or joints are present before shear initiation. Experimental results suggest that preexisting mechanical discontinuities (faults and/or joints) have a marked effect on the geometry of such systems, causing deflection, lateral distribution, and suppression of shears. A lower limit is placed on shear offset necessary to produce a throughgoing fault in systems containing preexisting structures. Fault zone development observed in these experiments provides new insight for kinematic interpretation of structural data from strike-slip fault zones on Earth, Venus, and other terrestrial bodies.

  16. When the Corporate Storm Strikes the Academy: Faculty Response Required

    ERIC Educational Resources Information Center

    DeBoy, James L.

    2015-01-01

    When the corporate storm strikes the academy, faculty must be willing and able to repel administrative assaults upon academic freedom, shared governance, and tenure. This paper will describe the on-going clash between administrators who embrace the corporate mindset and faculty who cherish traditions of shared governance and collegial…

  17. What To Do When Contagious Disease Strikes Your School.

    ERIC Educational Resources Information Center

    American Bar Association, Chicago, IL.

    This publication presents 10 documents collected to accompany a seminar entitled "What To Do When Contagious Disease Strikes Your School," presented at the 31st annual convention of the National Organization on Legal Problems of Education in 1985. The materials include (1) an agenda of the seminar listing the speakers, their topics, and the time…

  18. Strike Four: An Educational Paradigm Servicing Troublesome Behaviour Students.

    ERIC Educational Resources Information Center

    Netolicky, Cecilia

    For chronically troublesome students educational strategies of exclusion currently lead to revolving door syndrome, resulting in ever-increasing learning deficits, and further inappropriate behaviours. Strike Four is an educational paradigm servicing "category three alienated students" (exhibiting significant social and/or emotional difficulties…

  19. Topic 101: Eleven Campuses, One University, Many Strikes

    ERIC Educational Resources Information Center

    Navarro-Rivera, Pablo

    2010-01-01

    Students from the University of Puerto Rico (UPR) went on strike in April, and, soon after, 10 of the 11 campuses of a public system with more than 60,000 students were closed. "Once recintos, una universidad" (eleven campuses, one university) was the maxim students used to emphasize the concept of the UPR as a system unified by similar goals,…

  20. Determinants of Teacher Militancy: Factors Affecting the Decision to Strike.

    ERIC Educational Resources Information Center

    Tomkiewicz, Joseph

    1979-01-01

    Statistical analysis of factors offered as explanations for teacher militancy demonstrates that they possess little value in differentiating striking from nonstriking school districts. Boards cannot depend on objective measures alone in preparing for negotiations and might better aim their efforts in other directions. (Author/IRT)

  1. Using Primary Sources To Teach the Rail Strike of 1877.

    ERIC Educational Resources Information Center

    Lesh, Bruce

    1999-01-01

    Describes a lesson plan that utilizes two primary sources, a handbill announcing the reduction in Baltimore and Ohio rail workers' wages and a list of damages to Baltimore and Ohio Railroad property, in order to determine the causes and effects of the Rail Strike of 1877. Provides the two sources and other handouts. (CMK)

  2. Physicians' strike and general mortality: Croatia's experience of 2003.

    PubMed

    Erceg, Marijan; Kujundzić-Tiljak, Mirjana; Babić-Erceg, Andrea; Coric, Tanja; Lang, Slobodan

    2007-09-01

    The aim of the study was to establish whether the physicians' strike, which took place in Croatia in 2003, had an impact on the mortality of the population. Mortality data from the National Bureau of Statistics relating to the strike period (15 January - 14 February 2003) were selected and compared with the previous and subsequent periods of the same duration in 2001, 2002 and 2004. Of the 52,575 deaths in 2003, Croatia recorded 4,682 (8.9%, 95% Confidence interval 8.4-9.4) in the strike period from the 15th of January to the 14th of February 2003 or 1.1 deaths per 1000. No deviations of the 15th of January to the 14th of February period's share of the death total in relation to other observation periods were noted. It is impossible to associate the strike based on the figures shown in this paper with either an increase or decrease in population mortality. PMID:18041403

  3. Introduction: Mapping Teachers' Strikes--A "Professionalist" Approach

    ERIC Educational Resources Information Center

    Robert, Andre D.; Tyssens, Jeffrey

    2008-01-01

    This article aims to interpret teacher strikes through a multi-level analysis and the identification of a number of relevant factors relative to the professional project (in a neo-Weberian sense) of primary and secondary school teachers. In the first place the authors' interpretation is based on references to contextual and structural elements,…

  4. Recent physician strike in Israel: a health system under stress?

    PubMed Central

    2013-01-01

    In 2011, a series of physician strikes in Israel followed eight months of unsuccessful negotiations with the government (Ministry of Health and the Ministry of Finance). Strikes by physicians may be a warning that all is not well in a health system and protestors have claimed that they signify a system failure. In contrast, others argue that strikes have been a feature of the Israeli health system from its inception and should not be a cause for alarm. This paper analyses the Israeli health system from the perspective of the strikers' demands using the World Health Organisation’s six health system building blocks as a framework, including: service delivery; health workforce; information; medical products, vaccines and technologies; leadership and governance; and financing. While we recognise that the immediate causes of the 2011 strikes were concerns about salaries and working conditions, we argue that a complex set of interacting factors underlie the strikers' demands, resonating with issues relating to five of the WHO building blocks. We argue that of the five, three are most significant and limit progress with all the others: a disgruntled health workforce, many of whom believe that striking is the only way to be heard; a lack of leadership by the government in understanding and responding to physicians' concerns; and a purported information insufficiency, manifest as a lack of critique and analysis that may have prevented those at the top from making a reliable diagnosis of the system’s problems. This paper argues that there are cracks within the Israeli health system but that these are not irresolvable. The Israeli health system is a relatively new and popular health system, but there are no grounds for complacency. PMID:23947638

  5. Structural subprovinces of the Central Basin Platform, west Texas: Strike-slip bounded crustal blocks

    SciTech Connect

    Gardiner, W.B. )

    1990-05-01

    The Central Basin platform (CBP) of west Texas is composed of six structural blocks, which moved independently during the Ouachita orogeny. As the South American plate collided with North America the Wasson uplift on the northwestern shelf of the Permian basin acted as a buttress against which the CBP was compressed. Shear forces transmitted through the crust resulted in buckling, uplifting, and faulting of the greater CBP. Although the platform is dominated by vertical movement, it did not however, uplift as a single tectonic unit. Rather, it splintered into six megablocks, which moved simultaneously along oblique-slip fault systems. A tectonic model for formation of the CBP is useful for predicting the orientation and spacing of fault systems. The three structurally highest blocks on the CBP, the Eunice high, the Sand Hills high, and the Fort Stockton uplift, show three distinct positive gravity and magnetic anomalies. These county-sized blocks (35 x 80 km) share similar characteristics: (1) they are bounded by strike-slip faults that involve basement uplift; (2) they have maximum structural deformation along their margins where bends in the strike-slip fault system enhance compressions; and (3) their oil is trapped in high-angle fault structures (R-shears ) along the clock boundaries, but toward the center of the blocks, oil tends to accumulate at unconformity and fold traps. Strike-slip fault systems in west Texas are subtle, with only about 3-7 km of offset and commonly may be overlooked. However, detailed regional mapping indicates that these individual fault segments are parts of through-going systems, which are distributed in logical patterns based upon models for strike-slip tectonics.

  6. Effect of Acute Alterations in Foot Strike Patterns during Running on Sagittal Plane Lower Limb Kinematics and Kinetics.

    PubMed

    Valenzuela, Kevin A; Lynn, Scott K; Mikelson, Lisa R; Noffal, Guillermo J; Judelson, Daniel A

    2015-03-01

    that acute changes in foot strike patterns during shod running can create alterations in certain lower limb kinematic and kinetic measures that are not dependent on the preferred foot strike pattern of the individual. This research also challenges the contention that the impact transient spike in the vertical ground reaction force curve is only present during a rear foot strike type of running gait. Key pointsFootstrike pattern changes should be individually considered and implemented based on individual histories/abilitiesForefoot strike patterns increase external dorsiflexion momentsRearfoot strike patterns increase external knee flexion momentsRecreational shod runners are able to mimic habitual mechanics of different foot strike patterns. PMID:25729311

  7. Effect of Acute Alterations in Foot Strike Patterns during Running on Sagittal Plane Lower Limb Kinematics and Kinetics

    PubMed Central

    Valenzuela, Kevin A.; Lynn, Scott K.; Mikelson, Lisa R.; Noffal, Guillermo J.; Judelson, Daniel A.

    2015-01-01

    acute changes in foot strike patterns during shod running can create alterations in certain lower limb kinematic and kinetic measures that are not dependent on the preferred foot strike pattern of the individual. This research also challenges the contention that the impact transient spike in the vertical ground reaction force curve is only present during a rear foot strike type of running gait. Key points Footstrike pattern changes should be individually considered and implemented based on individual histories/abilities Forefoot strike patterns increase external dorsiflexion moments Rearfoot strike patterns increase external knee flexion moments Recreational shod runners are able to mimic habitual mechanics of different foot strike patterns PMID:25729311

  8. Update Direct-Strike Lightning Environment for Stockpile-to-Target Sequence

    SciTech Connect

    Uman, M A; Rakov, V A; Elisme, J O; Jordan, D M; Biagi, C J; Hill, J D

    2008-10-01

    The University of Florida has surveyed all relevant publications reporting lightning characteristics and presents here an up-to-date version of the direct-strike lightning environment specifications for nuclear weapons published in 1989 by R. J. Fisher and M. A. Uman. Further, we present functional expressions for current vs. time, current derivative vs. time, second current derivative vs. time, charge transfer vs. time, and action integral (specific energy) vs. time for first return strokes, for subsequent return strokes, and for continuing currents; and we give sets of constants for these expressions so that they yield approximately the median and extreme negative lightning parameters presented in this report. Expressions for the median negative lightning waveforms are plotted. Finally, we provide information on direct-strike lightning damage to metals such as stainless steel, which could be used as components of storage containers for nuclear waste materials; and we describe UF's new experimental research program to add to the sparse data base on the properties of positive lightning. Our literature survey, referred to above, is included in four Appendices. The following four sections (II, III, IV, and V) of this final report deal with related aspects of the research: Section II. Recommended Direct-Strike Median and Extreme Parameters; Section III. Time-Domain Waveforms for First Strokes, Subsequent Strokes, and Continuing Currents; Section IV. Damage to Metal Surfaces by Lightning Currents; and Section V. Measurement of the Characteristics of Positive Lightning. Results of the literature search used to derive the material in Section II and Section IV are found in the Appendices: Appendix 1. Return Stroke Current, Appendix 2. Continuing Current, Appendix 3. Positive Lightning, and Appendix 4. Lightning Damage to Metal Surfaces.

  9. Rocks in a Box: A Three-Point Problem.

    ERIC Educational Resources Information Center

    Leyden, Michael B.

    1981-01-01

    Describes a simulation drilling core activity involving the use of a physical model from which students gather data and solve a three-point problem to determine the strike and dip of a buried stratum. Includes descriptions of model making, data plots, and additional problems involving strike and dip. (DS)

  10. Implications of Incessant Strike Actions on the Implementation of Technical Education Programme in Nigeria

    ERIC Educational Resources Information Center

    Adavbiele, J. A.

    2015-01-01

    This paper was designed to x-ray the implications of incessant strike actions on the implementation of Technical education programme in Nigeria. The paper took an exploratory view on the concept of strike actions in Nigeria with particular references on notable strike actions that have occurred in Nigeria. The types of strike were explained and…

  11. Charge collection and SEU from angled ion strikes

    SciTech Connect

    Dodd, P.E.; Shaneyfelt, M.R.; Sexton, F.W.

    1997-03-01

    Single event upsets (SEUs) are caused in semiconductor microcircuits when charge is deposited in a sensitive volume of the circuit by an incident energetic particle. Collection of this charge causes a loss of information stored at the struck circuit node. Sensitive regions of a microcircuit typically consist of reverse-biased junctions which efficiently collect deposited charge through the influence of drift fields. During laboratory SEU testing, angled ion strikes are often used to conveniently mimic normally incident particles of higher linear energy transfer (LET). This practice is based on ion pathlengths through a thin rectangular parallelepiped (RPP) sensitive volume. Specifically, the authors assume that an angled strike deposits 1/cos{theta} more charge in the sensitive volume, which in turn is assumed to lead to 1/cos{theta} more charge collection at the sensitive node, and an increase in the particle`s effective LET to 1/cos{theta} higher than at normal incidence.

  12. Analysis of direct and nearby lightning strike data for aircraft

    NASA Technical Reports Server (NTRS)

    Giri, D. V.; Noss, R. S.; Phuoc, D. B.; Tesche, F. M.

    1983-01-01

    A method for interpreting direct strike and nearby strike lightning data on aircraft is discussed. The theoretical basis for the interpretation involves a transmission line model for the aircraft, and is discussed. Results of applying this model to the F-106 aircraft are presented and in the natural resonances are computed for several different electrical representations of the aircraft. The signal processing techniques useful for extracting pole (resonance) information from experimental data are discussed, and the use of these techniques on the measured lightning data is illustrated. Finally, the results of a related ground-based lightning experiment are discussed and data are presented. The purpose of this test was to gain additional understanding of the resonance properties of the F-106 aircraft.

  13. Dynamic behavior of elevator compensating sheave during buffer strike

    NASA Astrophysics Data System (ADS)

    Watanabe, S.; Okawa, T.

    2016-05-01

    This paper shows an elevator dynamic model that calculates the compensating sheave motion during a buffer strike. Our equivalent 2-degree-of-freedom vibration model of an elevator system, which consists of a car, a compensating sheave, and compensating ropes, can evaluate the dynamic tension of the compensating ropes caused by a buffer strike. The constraint force, which restricts the upward motion of the compensating sheave, is estimated from the dynamic rope tension. The constraint force is represented by the summation of two vibration modes and is the function of the limited distance of the compensating sheave's upward movement. Our formula, which evaluates the maximum constraint force, shows that a shorter limited distance of the compensating sheave increases the constraint force.

  14. Hunt's 'sincere' words only strike a false note.

    PubMed

    Scott, Graham

    2014-10-21

    The first strike by NHS staff over pay in more than 30 years - and the first by members of the Royal College of Midwives in its history - will hopefully force ministers to rethink their decision to freeze pay rates for 1.3 million health service staff. Those taking part in Monday's four-hour stoppage and this week's 'work-to-rule' deserve great credit for making a sacrifice so that everyone in the NHS may benefit. PMID:25315522

  15. Distribution of strike-slip faults on Europa

    NASA Astrophysics Data System (ADS)

    Hoppa, Gregory; Greenberg, Richard; Tufts, B. Randall; Geissler, Paul; Phillips, Cynthia; Milazzo, Moses

    2000-09-01

    Study of four different regions on Europa imaged by the Galileo spacecraft during its first 15 orbits has revealed 117 strike-slip faults. Europa appears to form preferentially right-lateral faults in the southern hemisphere and left-lateral faults in the northern hemisphere. This observation is consistent with a model where diurnal tides due to orbital eccentricity drive strike-slip motion through a process of ``walking,'' in which faults open and close out of phase with alternating right-and left-lateral shear. Lineaments that record both left-and right-lateral motion (e.g., Agave Linea) may record the accommodation of compression in nearby chaotic zones. Nearly all identified strike-slip faults were associated with double ridges or bands, and few were detected along ridgeless cracks. Thus the depth of cracks without ridges does not appear to have penetrated to the low-viscosity decoupling layer, required for diurnal displacement, but cracks that have developed ridges do extend down to such a level. This result supports a model for ridge formation that requires cracks to penetrate to a decoupling layer, such as a liquid water ocean.

  16. The fast and forceful kicking strike of the secretary bird.

    PubMed

    Portugal, Steven J; Murn, Campbell P; Sparkes, Emily L; Daley, Monica A

    2016-01-25

    The study of animal locomotion has uncovered principles that can be applied to bio-inspired robotics, prosthetics and rehabilitation medicine, while also providing insight into musculoskeletal form and function [1-4]. In particular, study of extreme behaviors can reveal mechanical constraints and trade-offs that have influenced evolution of limb form and function [1,2]. Secretary birds (Sagittarius serpentarius; Figure 1A) are large terrestrial birds of prey endemic to sub-Saharan Africa, which feed on snakes, lizards and small mammals [5]. They frequently kick and stamp on the prey's head until it is killed or incapacitated, particularly when dispatching larger lizards and venomous snakes [5]. The consequences of a missed strike when hunting venomous snakes can be deadly [5], so the kicking strikes of secretary birds require fast yet accurate neural control. Delivery of fast, forceful and accurate foot strikes that are sufficient to stun and kill prey requires precision targeting, demanding a high level of coordination between the visual and neuromuscular systems. PMID:26811886

  17. Further identification and treatment modalities in telephone mediated lightning strike

    NASA Technical Reports Server (NTRS)

    Andrews, Christopher J.; Darveniza, Mat

    1991-01-01

    The results are presented of a prospective survey of people injured by lightning impulses transmitted by the public telephone system. The results are compared with those of a previous retrospective survey. Various deficiencies in the methodology of the latter survey are addressed. A division into a population with severe injury and a population with mild injury is made based on medical history and examination taken immediately after a strike. The best predictors of severe injury were found to be the presence of symptoms beyond one week after the strike, and also the initial presence of musculoskeletal injuries. Psychological upset is also seen to be a significant factor in severe injury. The only physical parameter of strike which could be used as a predictor of severe injury was the presence of concomitant power system damage. The importance of earth bonding between power and telephone system is thus supported in a protection strategy. One author draws on experience in treating patients with these injuries to propose a treatment regimen for those with ongoing symptoms. The importance of evaluating and treating psychological and physical aspects is stressed.

  18. Nucleation and growth of strike slip faults in granite.

    USGS Publications Warehouse

    Segall, P.; Pollard, D.P.

    1983-01-01

    Fractures within granodiorite of the central Sierra Nevada, California, were studied to elucidate the mechanics of faulting in crystalline rocks, with emphasis on the nucleation of new fault surfaces and their subsequent propagation and growth. Within the study area the fractures form a single, subparallel array which strikes N50o-70oE and dips steeply to the S. Some of these fractures are identified as joints because displacements across the fracture surfaces exhibit dilation but no slip. The joints are filled with undeformed minerals, including epidote and chlorite. Other fractures are identified as small faults because they display left-lateral strike slip separations of up to 2m. Slickensides, developed on fault surfaces, plunge 0o-20o to the E. The faults occur parallel to, and in the same outcrop with, the joints. The faults are filled with epidote, chlorite, and quartz, which exhibit textural evidence of shear deformation. These observations indicate that the strike slip faults nucleated on earlier formed, mineral filled joints. Secondary, dilational fractures propagated from near the ends of some small faults contemporaneously with the left-lateral slip on the faults. These fractures trend 25o+ or -10o from the fault planes, parallel to the direction of inferred local maximum compressive stress. The faults did not propagate into intact rock in their own planes as shear fractures. -from Authors

  19. Characteristics of cloud-to-ground lightning strikes in the stratiform regions of mesoscale convective systems

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Zhang, Yijun; Liu, Hengyi; Yao, Wen; Meng, Qing

    2016-09-01

    To better understand the characteristics of cloud-to-ground lightning (CG) strikes in the stratiform regions of mesoscale convective systems (MCSs), radar and CG data from 10 MCS cases in China were comprehensively analyzed. Results show that stratiform CGs have characteristics distinct from those of convective CGs. A significant polarity bias appears in convective CGs, but the polarity bias in stratiform CGs is either undetectable or opposite that of the bias of convective CGs. The medians of the first return stroke current for positive and negative stratiform CGs have mean values of 59.7 kA and - 37.3 kA, respectively; these values are 26% and 24% higher than the corresponding mean values for positive and negative convective CGs, respectively. In contrast to stratiform CGs, the first return strokes of convective CGs have polarized currents. Most convective CGs have relatively low currents, but most CGs with maximum currents in MCSs also fall within convective CGs. In the 10 MCSs studied, most stratiform CGs strike the ground at or near the edge of a region whose maximum reflectivity (≥ 30 dBZ) occurs at 3-6 km height. The characteristics of reflectivity across this region are consistent with the reflectivity characteristics of the brightband; thus, this study provides important evidence for the relationship between the brightband and stratiform CGs. A charging mechanism based on the melting of ice particles is speculated to be the key to initiating stratiform lightning. This mechanism could induce the propagation of lightning from the convective region to the stratiform region, thereby explaining the observed strikes on the ground nearby.

  20. What can we learn from 20 years of interseismic GPS measurements across strike-slip faults?

    NASA Astrophysics Data System (ADS)

    Vernant, Philippe

    2015-03-01

    I use GPS interseismic velocities and classic 2D elastic half-space models with a screw dislocation to estimate the long-term fault slip rate, locking depth, and the offset between the surface fault trace and the location of the dislocation below the seismogenic zone for 13 segments along 8 major strike-slip faults. Using deduced strike-slip rates and the position of the dislocation to normalize the interseismic velocities to facilitate comparison of spatial patterns of deformation, I show that no substantial differences can be detected, ruling out a large asymmetry in interseismic velocities across the 8 faults used in this study. Only the Carrizo Plain segment of the San Andreas Fault shows a significant asymmetry that cannot be explained by shifting the position of the dislocation at depth relative to the fault trace. However, the resulting perturbation is less than 10% of total strike-slip rate. Fault traces are usually curved, defining a concave side. When the dislocation at depth is significantly offset from the fault trace, the shift is always toward the block on the concave side of the fault trace. This suggests that the fault zone in the lower crust may develop a simpler geometry more consistent with relative motion across the fault than its upper seismogenic part constrained by the structural complexity of the brittle crust. Since the faults used in this study are at different times in their interseismic period, comparing the interseismic velocity fields across them allows identification of possible variations of the interseismic velocities with time. When normalized by slip rate and dislocation location, all the faults show the same interseismic strain with no significant differences between deduced locking depths. These comparisons suggest that if temporal variations occur as suggested by some dynamic earthquake cycle models, they are small and below the accuracy of the available geodetic measurements.

  1. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin

    NASA Astrophysics Data System (ADS)

    van Hengstum, Peter J.; Donnelly, Jeffrey P.; Fall, Patricia L.; Toomey, Michael R.; Albury, Nancy A.; Kakuk, Brian

    2016-02-01

    Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval.

  2. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin

    PubMed Central

    van Hengstum, Peter J.; Donnelly, Jeffrey P.; Fall, Patricia L.; Toomey, Michael R.; Albury, Nancy A.; Kakuk, Brian

    2016-01-01

    Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval. PMID:26906670

  3. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin.

    PubMed

    van Hengstum, Peter J; Donnelly, Jeffrey P; Fall, Patricia L; Toomey, Michael R; Albury, Nancy A; Kakuk, Brian

    2016-01-01

    Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval. PMID:26906670

  4. Along-strike translation of a fossil slab

    NASA Astrophysics Data System (ADS)

    Eichenbaum-Pikser, J. M.; Forsyth, D. W.; Hirth, G.

    2011-12-01

    The Isabella anomaly is a high seismic velocity anomaly beneath the southern Central Valley of California. Breaking from previous interpretations of the anomaly as a lithospheric drip (Zandt and Carrigan, 1993) or delaminated Sierra Nevada root (Zandt et al., 2004), Forsyth et al. (2011) propose that it is a remnant slab, left over from Cenozoic subduction, attached to the Monterey microplate and translating along-strike with the Pacific plate underneath the edge of the North American plate. This hypothesis requires the slab to translate hundreds of kilometers along strike while remaining intact and attached to the Pacific plate despite drag from the surrounding asthenosphere and overriding lithosphere. Using COMSOL Multiphysics, we design 3-D finite element fluid flow models to simulate this scenario, and calculate the viscosity ratio required between the slab and the surrounding asthenosphere in order for the slab to translate undeformed. The ratio needed increases with downdip extent of the slab, and decreases with slab dip; for geometries approximating that of our proposed slab, it ranges from 10^2 to 10^4. Given the thermal and hydrological history of the slab, mantle flow laws predict viscosity contrasts greater than or equal to these requirements. As such, we conclude that along-strike translation of a remnant slab is entirely feasible, and serves as possible explanation of the Isabella anomaly. The significance of this finding extends beyond our general understanding of subduction dynamics, in that the presence of such a slab could have interesting implications for the water budget of the San Andreas Fault and its role in aseismic slip.

  5. Pericollisional strike-slip basins in western Cordillera, Canada

    SciTech Connect

    Eisbacher, G.H.

    1984-04-01

    The late Mesozoic-Paleogene evolution of the Canadian Cordillera was dominated by accretion of elongate crustal blocks against the North American craton. Geologic and paleomagnetic evidence suggest that these exotic terranes dispersed from volcanic arcs and oceanic platforms and approached North America along anastomosing right-lateral faults with great cumulative displacement. Obduction of oceanic allochthons was followed by transpressive thickening and regional metamorphism of the cratonic margin in the mid-Jurassic. Strike-slip motion and emplacement of plutonic rocks continued near relict sutures and reactivated deep faults. Sedimentary basins related to strike-slip faults formed by elongation of accreted terranes (''Stikinia'' and ''Wrangellia'') and by shear within the deformed cratonic margin zone (''Rocky Mountain Trench''). Subsidence is reflected by northwest-southeast stretching along pull-apart structures, and by massive influx of turbidites from incipient collision zones and relict are relief. It was interrupted and outlived by rotation of blocks, folding of basin sediments, and vigorous progradation of deltaic-fluvial clastics from rising collision belts. Transition from predominant transtension to prevailing transpression is diachronous from basin to basin. Near the Stikine-Wrangellia collision zone (Bowser basin), it occurred in the Late Jurassic; along the Stikine-Wrangellia border it occurred in the mid to Late Cretaceous. Only small nonmarine basins developed in the Rocky Mountain Trench system, which, in its southern-most part, was closed completely during Paleogene thrust faulting. The strike-slip basins of the western Canadian Cordillera were subject to high regional heat flow and also suffered from widespread intrusion of paleogene granitoids. Therefore, they are generally poor oil and gas prospects.

  6. Biomechanics: deadly strike mechanism of a mantis shrimp.

    PubMed

    Patek, S N; Korff, W L; Caldwell, R L

    2004-04-22

    Stomatopods (mantis shrimp) are well known for the feeding appendages they use to smash shells and impale fish. Here we show that the peacock mantis shrimp (Odontodactylus scyllarus) generates an extremely fast strike that requires major energy storage and release, which we explain in terms of a saddle-shaped exoskeletal spring mechanism. High-speed images reveal the formation and collapse of vapour bubbles next to the prey due to swift movement of the appendage towards it, indicating that O. scyllarus may use destructive cavitation forces to damage its prey. PMID:15103366

  7. Negative ion beam characterisation in BATMAN by mini-STRIKE: Improved design and new measurements

    NASA Astrophysics Data System (ADS)

    Serianni, G.; Bonomo, F.; Brombin, M.; Cervaro, V.; Chitarin, G.; Cristofaro, S.; Delogu, R.; De Muri, M.; Fasolo, D.; Fonnesu, N.; Franchin, L.; Franzen, P.; Ghiraldelli, R.; Molon, F.; Muraro, A.; Pasqualotto, R.; Ruf, B.; Schiesko, L.; Tollin, M.; Veltri, P.

    2015-04-01

    The ITER project requires additional heating provided by two injectors of neutral beams resulting from the neutralisation of accelerated negative ions. To study and optimise negative ion production, the SPIDER test facility (particle energy 100keV; beam current 50A) is under construction in Padova, with the aim of testing beam characteristics and to verify the source proper operation. The SPIDER beam will be characterised by the instrumented calorimeter STRIKE, whose main components are one-directional carbon fibre carbon composite tiles. Some prototype tiles have been employed in 2012 as a small-scale version (mini-STRIKE) of the entire system to investigate the features of the beam from BATMAN at IPP-Garching. As the BATMAN beamlets are superposed at the measurement position, about 1m from the grounded grid, an actively cooled copper mask is located in front of the tiles; holes in the mask create an artificial beamlet structure. Recently the mini-STRIKE has been updated, taking into account the results obtained in the first campaign. In particular the spatial resolution of the system has been improved by increasing the number of the copper mask holes. Moreover a custom measurement system has been realized for the thermocouple signals and employed in BATMAN in view of its use in SPIDER. The present contribution gives a description of the new design of the system as well as of the thermocouple measurements system and its field test. A new series of measurements has been carried out in BATMAN. The BATMAN beam characterisation in different experimental conditions is presented.

  8. Negative ion beam characterisation in BATMAN by mini-STRIKE: Improved design and new measurements

    SciTech Connect

    Serianni, G. Brombin, M.; Cervaro, V.; Chitarin, G.; Delogu, R.; Fasolo, D.; Fonnesu, N.; Franchin, L.; Ghiraldelli, R.; Molon, F.; Pasqualotto, R.; Tollin, M.; Veltri, P.; Bonomo, F.; Cristofaro, S.; De Muri, M.; Franzen, P.; Ruf, B.; Schiesko, L.; Muraro, A.

    2015-04-08

    The ITER project requires additional heating provided by two injectors of neutral beams resulting from the neutralisation of accelerated negative ions. To study and optimise negative ion production, the SPIDER test facility (particle energy 100keV; beam current 50A) is under construction in Padova, with the aim of testing beam characteristics and to verify the source proper operation. The SPIDER beam will be characterised by the instrumented calorimeter STRIKE, whose main components are one-directional carbon fibre carbon composite tiles. Some prototype tiles have been employed in 2012 as a small-scale version (mini-STRIKE) of the entire system to investigate the features of the beam from BATMAN at IPP-Garching. As the BATMAN beamlets are superposed at the measurement position, about 1m from the grounded grid, an actively cooled copper mask is located in front of the tiles; holes in the mask create an artificial beamlet structure. Recently the mini-STRIKE has been updated, taking into account the results obtained in the first campaign. In particular the spatial resolution of the system has been improved by increasing the number of the copper mask holes. Moreover a custom measurement system has been realized for the thermocouple signals and employed in BATMAN in view of its use in SPIDER. The present contribution gives a description of the new design of the system as well as of the thermocouple measurements system and its field test. A new series of measurements has been carried out in BATMAN. The BATMAN beam characterisation in different experimental conditions is presented.

  9. Battlespace weather and EM/EO conditions for joint strike support

    NASA Astrophysics Data System (ADS)

    Rosenthal, Jay; Helvey, Roger A.; McGovern, Matt; Greiman, Paul; Cohenour, Bernie; Ruth, Dennis

    1997-09-01

    Battlespace meteorological and oceanographic (METOC) conditions can be defined and displayed using the Navy's C4ISR architecture for use in strike planning, optimizing weapons performance, and postoperation assessment. Using the Tactical Environmental Support System (TESS), METOC satellite imagery has been exploited to derive estimates of temperature and cloud conditions along Tomahawk flight paths, and integrated with operational geometry to support missile launches conducted during Joint Warrior Interoperability Demonstration (JWID-95). The integrated and fused displays were sent from the Battle Management Interoperability Center (BMIC) at the Naval Air Warfare Center Weapons Division, Point Mugu, and transmitted to fleet units where they were inserted as strike warfare support products on a home page for transmission to other JWID participants. Other support techniques are also being implemented using home page/internet technology. The EMIEO propagation environment is being characterized remotely by application of the "satellite-JR duct technique" which allows duct heights to be displayed over low-cloud regions over subtropical ocean areas. To provide duct height estimates in regions without clouds or in-situ measurements, or predictions of ducting conditions, the "equivalent altitude" and "experduct" techniques are employed to demonstrate additional automated capabilities using synoptic weather considerations.

  10. Is the foot striking pattern more important than barefoot or shod conditions in running?

    PubMed

    Shih, Yo; Lin, Kuan-Lun; Shiang, Tzyy-Yuang

    2013-07-01

    People have advocated barefoot running, claiming that it is better suited to human nature. Humans usually run barefoot using a forefoot strike and run shod using a heel strike. The striking pattern was thought to be a key factor that contributes to the benefit of barefoot running. The purpose of this study is to use scientific data to prove that the striking pattern is more important than barefoot or shod conditions for runners on running injuries prevention. Twelve habitually male shod runners were recruited to run under four varying conditions: barefoot running with a forefoot strike, barefoot running with a heel strike, shod running with a forefoot strike, and shod running with a heel strike. Kinetic and kinematic data and electromyography signals were recorded during the experiments. The results showed that the lower extremity can gain more compliance when running with a forefoot strike. Habitually shod runners can gain more shock absorption by changing the striking pattern to a forefoot strike when running with shoes and barefoot conditions. Habitually shod runners may be subject to injuries more easily when they run barefoot while maintaining their heel strike pattern. Higher muscle activity in the gastrocnemius was observed when running with a forefoot strike, which may imply a greater training load on the muscle and a tendency for injury. PMID:23507028

  11. Evidence and dynamics for the change of strike-slip direction of the Changle Nanao ductile shear zone, southeastern China

    NASA Astrophysics Data System (ADS)

    Zhihong, Wang; Huafu, Lu

    1997-12-01

    The Changle-Nanao ductile shear zone was developed from a suture zone. The evidence from the ductile fabrics and mylonitic microstructures indicates that the strike-slip was sinistral during pre-collision. It became dominantly dextral in the syn-collision stage in late Early Cretaceous. The dextral strike-slip movement continued in the post-collision stage with extension as the dominant process. The strike-slip movement of the zone was strictly controlled by dynamics of collision between the Fujian (Min)-Taiwan (Tai) microcontinent and the Fujian (Min)-Zhejiang (Zhe) Mesozoic volcanic arc during the time interval of 100-120 Ma. The Min-Tai microcontinent in which the ductile shear zone developed might have been located originally to the south of its present position. The northward migration of the microcontinent had contributed to a few hundred kilometers of drift rather than a shear displacement. The real shear displacement is small due to the change of strike-slip direction from sinistral to dextral.

  12. Fast rupture propagation for large strike-slip earthquakes

    NASA Astrophysics Data System (ADS)

    Wang, Dun; Mori, Jim; Koketsu, Kazuki

    2016-04-01

    Studying rupture speeds of shallow earthquakes is of broad interest because it has a large effect on the strong near-field shaking that causes damage during earthquakes, and it is an important parameter that reflects stress levels and energy on a slipping fault. However, resolving rupture speed is difficult in standard waveform inversion methods due to limited near-field observations and the tradeoff between rupture speed and fault size for teleseismic observations. Here we applied back-projection methods to estimate the rupture speeds of 15 Mw ≥ 7.8 dip-slip and 8 Mw ≥ 7.5 strike-slip earthquakes for which direct P waves are well recorded in Japan on Hi-net, or in North America on USArray. We found that all strike-slip events had very fast average rupture speeds of 3.0-5.0 km/s, which are near or greater than the local shear wave velocity (supershear). These values are faster than for thrust and normal faulting earthquakes that generally rupture with speeds of 1.0-3.0 km/s.

  13. Along-strike translation of a fossil slab

    NASA Astrophysics Data System (ADS)

    Pikser, Jacob E.; Forsyth, Donald W.; Hirth, Greg

    2012-05-01

    The Isabella anomaly is a high seismic velocity anomaly beneath the southern Central Valley of California that has previously been interpreted to represent a lithospheric drip or delaminated Sierra Nevada root. However, recent work suggests that the anomaly is a remnant slab, left over from Cenozoic subduction, attached to the Pacific plate underneath the edge of the North American plate. This hypothesis requires the slab to translate hundreds of kilometers along-strike while remaining intact and attached to the Pacific plate despite drag from the surrounding asthenosphere and overriding lithosphere. We use 3-D finite element models to simulate this scenario, and calculate the viscosity ratio between the slab and the surrounding asthenosphere required for the slab to translate undeformed. The required viscosity ratio increases with increasing downdip extent of the slab, and decreases with increasing slab dip; for geometries approximating that of our proposed slab, the required ratio ranges from 102 to 104. Given the thermal and petrologic history of the slab, mantle flow laws predict viscosity contrasts greater than or equal to these requirements. As such, we conclude that along-strike translation of a remnant slab is feasible, and serves as a possible explanation of the Isabella anomaly. The significance of this finding extends beyond our general understanding of subduction dynamics, in that the presence of such a slab could have implications for the water budget of the San Andreas Fault and its role in aseismic slip.

  14. Modeling raindrop strike performance on copper wash-off from vine leaves.

    PubMed

    Pérez-Rodríguez, P; Soto-Gómez, D; López-Periago, J E; Paradelo, M

    2015-03-01

    Copper lost in foliar wash-off from vine leaves treated with Cu-based fungicides was analyzed with a single-drop rainfall simulator. The temporal losses of the particulate Cu (CuP) and the solution Cu (CuS) from raindrop strikes on leaves were modeled using a Poisson point process. This model estimated maximum detachment rates of 0.82 ng CuP and 0.033 ng CuS per raindrop. The total amount of Cu (CuT) in the leaves before rainfall ranged between 0.4 and 4.4 g Cu kg(-1) dry weight. Wash-off reduced the amount of CuT present in the leaves by 0.6 g kg(-1). Particulate losses of CuT ranged from 75 to 90%, while soluble losses of CuT ranged from 10 to 25%. The kinetic energy of the raindrops influenced the loss of CuS but not the loss of CuP. The Poisson point approach can provide an interesting starting point to model non-point source pollution produced from agricultural chemicals washed-off by rain. PMID:25560655

  15. Influence of strike object grounding on close lightning electric fields

    NASA Astrophysics Data System (ADS)

    Baba, Yoshihiro; Rakov, Vladimir A.

    2008-06-01

    Using the finite difference time domain (FDTD) method, we have calculated vertical electric field Ez, horizontal (radial) electric field Eh, and azimuthal magnetic field Hϕ produced on the ground surface by lightning strikes to 160-m- and a 553-m-high conical strike objects representing the Peissenberg tower (Germany) and the CN Tower (Canada), respectively. The fields were computed for a typical subsequent stroke at distances d' from the bottom of the object ranging from 5 to 100 m for the 160-m tower and from 10 to 300 m for the 553-m tower. Grounding of the 160-m object was assumed to be accomplished by its underground basement represented by a 10-m-radius and 8-m-long perfectly conducting cylinder with or without a reference ground plane located 2 m below. The reference ground plane simulates, to some extent, a higher-conducting ground layer that is expected to exist below the water table. The configuration without reference ground plane actually means that this plane is present, but is located at an infinitely large depth. Grounding of the 553-m object was modeled in a similar manner but in the absence of reference ground plane only. In all cases considered, waveforms of Eh and Hϕ are not much influenced by the presence of strike object, while waveforms of Ez are. Waveforms of Ez are essentially unipolar (as they are in the absence of strike object) when the ground conductivity σ is 10 mS/m (the equivalent transient grounding impedance is several ohms) or greater. Thus, for the CN Tower, for which σ ≥ 10 mS/m, the occurrence of Ez polarity change is highly unlikely. For the 160-m tower and for σ = 1 and 0.1 mS/m, waveforms of Ez become bipolar (exhibit polarity change) at d' ≤ 10 m and d' ≤ 50 m, respectively, regardless of the presence of the reference ground plane. The corresponding equivalent transient grounding impedances are about 30 and 50 Ω in the absence of the reference ground plane and smaller than 10 Ω in the presence of the reference

  16. The Right to Strike in Public Employment. Key Issues Series--No. 15. Second Edition, Revised.

    ERIC Educational Resources Information Center

    Sterret, Grace; Aboud, Antone

    Since the 1960s, the number of strikes by public employees, especially local government employees, has increased, and the number of employees belonging to unions or associations has about tripled. Recently, attention has been focused on strikes by public employees as a result of the strike in 1981 by air traffic controllers and their subsequent…

  17. 14 CFR 323.15 - Report to be filed after strikes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Report to be filed after strikes. 323.15 Section 323.15 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... filed after strikes. (a) Within 15 days following resumption of service after a strike, an air...

  18. 48 CFR 1252.222-71 - Strikes or picketing affecting access to a DOT facility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Provisions and Clauses 1252.222-71 Strikes or picketing affecting access to a DOT facility. As prescribed in (TAR) 48 CFR 1222.101-71(b), insert the following clause: Strikes or Picketing Affecting Access to a... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Strikes or...

  19. 48 CFR 1252.222-70 - Strikes or picketing affecting timely completion of the contract work.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Text of Provisions and Clauses 1252.222-70 Strikes or picketing affecting timely completion of the contract work. As prescribed in (TAR) 48 CFR 1222.101-71(a), insert the following clause: Strikes or... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Strikes or...

  20. 48 CFR 1252.222-70 - Strikes or picketing affecting timely completion of the contract work.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Text of Provisions and Clauses 1252.222-70 Strikes or picketing affecting timely completion of the contract work. As prescribed in (TAR) 48 CFR 1222.101-71(a), insert the following clause: Strikes or... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Strikes or...

  1. 48 CFR 3052.222-70 - Strikes or picketing affecting timely completion of the contract work.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Strikes or picketing affecting timely completion of the contract work. As prescribed in (HSAR) 48 CFR 3022.101-71(a), insert the following clause: Strikes or Picketing Affecting Timely Completion of the... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Strikes or...

  2. 48 CFR 3052.222-70 - Strikes or picketing affecting timely completion of the contract work.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Strikes or picketing affecting timely completion of the contract work. As prescribed in (HSAR) 48 CFR 3022.101-71(a), insert the following clause: Strikes or Picketing Affecting Timely Completion of the... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Strikes or...

  3. 48 CFR 1252.222-70 - Strikes or picketing affecting timely completion of the contract work.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Text of Provisions and Clauses 1252.222-70 Strikes or picketing affecting timely completion of the contract work. As prescribed in (TAR) 48 CFR 1222.101-71(a), insert the following clause: Strikes or... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Strikes or...

  4. 48 CFR 1252.222-71 - Strikes or picketing affecting access to a DOT facility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Provisions and Clauses 1252.222-71 Strikes or picketing affecting access to a DOT facility. As prescribed in (TAR) 48 CFR 1222.101-71(b), insert the following clause: Strikes or Picketing Affecting Access to a... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Strikes or...

  5. 48 CFR 3052.222-70 - Strikes or picketing affecting timely completion of the contract work.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Strikes or picketing affecting timely completion of the contract work. As prescribed in (HSAR) 48 CFR 3022.101-71(a), insert the following clause: Strikes or Picketing Affecting Timely Completion of the... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Strikes or...

  6. 48 CFR 1252.222-70 - Strikes or picketing affecting timely completion of the contract work.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Text of Provisions and Clauses 1252.222-70 Strikes or picketing affecting timely completion of the contract work. As prescribed in (TAR) 48 CFR 1222.101-71(a), insert the following clause: Strikes or... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Strikes or...

  7. Industrial Actions in Schools: Strikes and Student Achievement. NBER Working Paper No. 16846

    ERIC Educational Resources Information Center

    Baker, Michael

    2011-01-01

    While many jurisdictions ban teacher strikes on the assumption that they harm students, there is surprisingly little research on this question. The majority of existing studies make cross section comparisons of students who do or do not experience a strike, and report that strikes do not affect student performance. I present new estimates from a…

  8. 48 CFR 3052.222-70 - Strikes or picketing affecting timely completion of the contract work.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Strikes or picketing affecting timely completion of the contract work. As prescribed in (HSAR) 48 CFR 3022.101-71(a), insert the following clause: Strikes or Picketing Affecting Timely Completion of the... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Strikes or...

  9. 14 CFR 323.15 - Report to be filed after strikes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Report to be filed after strikes. 323.15 Section 323.15 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... filed after strikes. (a) Within 15 days following resumption of service after a strike, an air...

  10. 48 CFR 1252.222-71 - Strikes or picketing affecting access to a DOT facility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Provisions and Clauses 1252.222-71 Strikes or picketing affecting access to a DOT facility. As prescribed in (TAR) 48 CFR 1222.101-71(b), insert the following clause: Strikes or Picketing Affecting Access to a... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Strikes or...

  11. 48 CFR 1252.222-71 - Strikes or picketing affecting access to a DOT facility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Provisions and Clauses 1252.222-71 Strikes or picketing affecting access to a DOT facility. As prescribed in (TAR) 48 CFR 1222.101-71(b), insert the following clause: Strikes or Picketing Affecting Access to a... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Strikes or...

  12. 14 CFR 323.15 - Report to be filed after strikes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Report to be filed after strikes. 323.15 Section 323.15 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... filed after strikes. (a) Within 15 days following resumption of service after a strike, an air...

  13. 48 CFR 1252.222-70 - Strikes or picketing affecting timely completion of the contract work.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Text of Provisions and Clauses 1252.222-70 Strikes or picketing affecting timely completion of the contract work. As prescribed in (TAR) 48 CFR 1222.101-71(a), insert the following clause: Strikes or... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Strikes or...

  14. 14 CFR 323.15 - Report to be filed after strikes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Report to be filed after strikes. 323.15 Section 323.15 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... filed after strikes. (a) Within 15 days following resumption of service after a strike, an air...

  15. 48 CFR 1252.222-71 - Strikes or picketing affecting access to a DOT facility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Provisions and Clauses 1252.222-71 Strikes or picketing affecting access to a DOT facility. As prescribed in (TAR) 48 CFR 1222.101-71(b), insert the following clause: Strikes or Picketing Affecting Access to a... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Strikes or...

  16. 14 CFR 323.15 - Report to be filed after strikes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Report to be filed after strikes. 323.15 Section 323.15 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... filed after strikes. (a) Within 15 days following resumption of service after a strike, an air...

  17. Magma storage in a strike-slip caldera

    PubMed Central

    Saxby, J.; Gottsmann, J.; Cashman, K.; Gutiérrez, E.

    2016-01-01

    Silicic calderas form during explosive volcanic eruptions when magma withdrawal triggers collapse along bounding faults. The nature of specific interactions between magmatism and tectonism in caldera-forming systems is, however, unclear. Regional stress patterns may control the location and geometry of magma reservoirs, which in turn may control the spatial and temporal development of faults. Here we provide new insight into strike-slip volcano-tectonic relations by analysing Bouguer gravity data from Ilopango caldera, El Salvador, which has a long history of catastrophic explosive eruptions. The observed low gravity beneath the caldera is aligned along the principal horizontal stress orientations of the El Salvador Fault Zone. Data inversion shows that the causative low-density structure extends to ca. 6 km depth, which we interpret as a shallow plumbing system comprising a fractured hydrothermal reservoir overlying a magmatic reservoir with vol% exsolved vapour. Fault-controlled localization of magma constrains potential vent locations for future eruptions. PMID:27447932

  18. Dynamics of fault interaction - Parallel strike-slip faults

    NASA Astrophysics Data System (ADS)

    Harris, Ruth A.; Day, Steven M.

    1993-03-01

    We use a 2D finite difference computer program to study the effect of fault steps on dynamic ruptures. Our results indicate that a strike-slip earthquake is unlikely to jump a fault step wider than 5 km, in correlation with field observations of moderate to great-sized earthquakes. We also find that dynamically propagating ruptures can jump both compressional and dilational fault steps, although wider dilational fault steps can be jumped. Dilational steps tend to delay the rupture for a longer time than compressional steps do. This delay leads to a slower apparent rupture velocity in the vicinity of dilational steps. These 'dry' cases assumed hydrostatic or greater pore-pressures but did not include the effects of changing pore pressures. In an additional study, we simulated the dynamic effects of a fault rupture on 'undrained' pore fluids to test Sibson's (1985, 1986) suggestion that 'wet' dilational steps are a barrier to rupture propagation. Our numerical results validate Sibson's hypothesis.

  19. A striking reduction of simple loudness adaptation in autism

    PubMed Central

    Lawson, Rebecca P.; Aylward, Jessica; White, Sarah; Rees, Geraint

    2015-01-01

    Reports of sensory disturbance, such as loudness sensitivity or sound intolerance, are ubiquitous in Autism Spectrum Disorder (ASD) but a mechanistic explanation for these perceptual differences is lacking. Here we tested adaptation to loudness, a process that regulates incoming sensory input, in adults with ASD and matched controls. Simple loudness adaptation (SLA) is a fundamental adaptive process that reduces the subjective loudness of quiet steady-state sounds in the environment over time, whereas induced loudness adaptation (ILA) is a means of generating a reduction in the perceived volume of louder sounds. ASD participants showed a striking reduction in magnitude and rate of SLA relative to age and ability-matched typical adults, but in contrast ILA remained intact. Furthermore, rate of SLA predicted sensory sensitivity coping strategies in the ASD group. These results provide the first evidence that compromised neural mechanisms governing fundamental adaptive processes might account for sound sensitivity in ASD. PMID:26537694

  20. Electrical Characterizations of Lightning Strike Protection Techniques for Composite Materials

    NASA Technical Reports Server (NTRS)

    Szatkowski, George N.; Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Mielnik, John J.

    2009-01-01

    The growing application of composite materials in commercial aircraft manufacturing has significantly increased the risk of aircraft damage from lightning strikes. Composite aircraft designs require new mitigation strategies and engineering practices to maintain the same level of safety and protection as achieved by conductive aluminum skinned aircraft. Researchers working under the NASA Aviation Safety Program s Integrated Vehicle Health Management (IVHM) Project are investigating lightning damage on composite materials to support the development of new mitigation, diagnosis & prognosis techniques to overcome the increased challenges associated with lightning protection on composite aircraft. This paper provides an overview of the electrical characterizations being performed to support IVHM lightning damage diagnosis research on composite materials at the NASA Langley Research Center.

  1. A Probabilistic, Facility-Centric Approach to Lightning Strike Location

    NASA Technical Reports Server (NTRS)

    Huddleston, Lisa L.; Roeder, William p.; Merceret, Francis J.

    2012-01-01

    A new probabilistic facility-centric approach to lightning strike location has been developed. This process uses the bivariate Gaussian distribution of probability density provided by the current lightning location error ellipse for the most likely location of a lightning stroke and integrates it to determine the probability that the stroke is inside any specified radius of any location, even if that location is not centered on or even with the location error ellipse. This technique is adapted from a method of calculating the probability of debris collisionith spacecraft. Such a technique is important in spaceport processing activities because it allows engineers to quantify the risk of induced current damage to critical electronics due to nearby lightning strokes. This technique was tested extensively and is now in use by space launch organizations at Kennedy Space Center and Cape Canaveral Air Force Station. Future applications could include forensic meteorology.

  2. Magma storage in a strike-slip caldera

    NASA Astrophysics Data System (ADS)

    Saxby, J.; Gottsmann, J.; Cashman, K.; Gutiérrez, E.

    2016-07-01

    Silicic calderas form during explosive volcanic eruptions when magma withdrawal triggers collapse along bounding faults. The nature of specific interactions between magmatism and tectonism in caldera-forming systems is, however, unclear. Regional stress patterns may control the location and geometry of magma reservoirs, which in turn may control the spatial and temporal development of faults. Here we provide new insight into strike-slip volcano-tectonic relations by analysing Bouguer gravity data from Ilopango caldera, El Salvador, which has a long history of catastrophic explosive eruptions. The observed low gravity beneath the caldera is aligned along the principal horizontal stress orientations of the El Salvador Fault Zone. Data inversion shows that the causative low-density structure extends to ca. 6 km depth, which we interpret as a shallow plumbing system comprising a fractured hydrothermal reservoir overlying a magmatic reservoir with vol% exsolved vapour. Fault-controlled localization of magma constrains potential vent locations for future eruptions.

  3. Stress accumulated mechanisms on strike-slip faults

    NASA Technical Reports Server (NTRS)

    Turcotte, D. L.

    1980-01-01

    The tectonic framework causing seismicity on the San Andreas and North Anatolian faults can be understood in terms of plate tectonics. However, the mechanisms responsible for the distribution of seismicity in space and time on these faults are poorly understood. The upper part of the crust apparently behaves elastically in storing energy that is released during an earthquake. The relatively small distances from the fault in which stress is stored argue in favor of a plate with a thickness of 5-10 km. The interaction of this plate with a lower crust that is behaving as a fluid damps the seismic cycling in distances of the order of 10 km from the fault. Low measured heat flow also argues in favor of a thin plate with a low stress level on the fault. Future measurements of stress, strain, and heat flow should help to provide a better understanding of the basic mechanisms governing the behavior of strike-slip faults.

  4. Reactivated strike slip faults: examples from north Cornwall, UK

    NASA Astrophysics Data System (ADS)

    Kim, Young-Seog; Andrews, Jim R.; Sanderson, David J.

    2001-10-01

    Several strike-slip faults at Crackington Haven, UK show evidence of right-lateral movement with tip cracks and dilatational jogs, which have been reactivated by left-lateral strike-slip movement. Evidence for reactivation includes two slickenside striae on a single fault surface, two groups of tip cracks with different orientations and very low displacement gradients or negative (left-lateral) displacements at fault tips. Evidence for the relative age of the two strike-slip movements is (1) the first formed tip cracks associated with right-lateral slip are deformed, whereas the tip cracks formed during left-lateral slip show no deformation; (2) some of the tip cracks associated with right-lateral movement show left-lateral reactivation; and (3) left-lateral displacement is commonly recorded at the tips of dominantly right-lateral faults. The orientation of the tip cracks to the main fault is 30-70° clockwise for right-lateral slip, and 20-40° counter-clockwise for left-lateral slip. The structure formed by this process of strike-slip reactivation is termed a "tree structure" because it is similar to a tree with branches. The angular difference between these two groups of tip cracks could be interpreted as due to different stress distribution (e.g., transtensional/transpressional, near-field or far-field stress), different fracture modes or fractures utilizing pre-existing planes of weakness. Most of the d- x profiles have similar patterns, which show low or negative displacement at the segment fault tips. Although the d- x profiles are complicated by fault segments and reactivation, they provide clear evidence for reactivation. Profiles that experienced two opposite slip movements show various shapes depending on the amount of displacement and the slip sequence. For a larger slip followed by a smaller slip with opposite sense, the profile would be expected to record very low or reverse displacement at fault tips due to late-stage tip propagation. Whereas for a

  5. Magma storage in a strike-slip caldera.

    PubMed

    Saxby, J; Gottsmann, J; Cashman, K; Gutiérrez, E

    2016-01-01

    Silicic calderas form during explosive volcanic eruptions when magma withdrawal triggers collapse along bounding faults. The nature of specific interactions between magmatism and tectonism in caldera-forming systems is, however, unclear. Regional stress patterns may control the location and geometry of magma reservoirs, which in turn may control the spatial and temporal development of faults. Here we provide new insight into strike-slip volcano-tectonic relations by analysing Bouguer gravity data from Ilopango caldera, El Salvador, which has a long history of catastrophic explosive eruptions. The observed low gravity beneath the caldera is aligned along the principal horizontal stress orientations of the El Salvador Fault Zone. Data inversion shows that the causative low-density structure extends to ca. 6 km depth, which we interpret as a shallow plumbing system comprising a fractured hydrothermal reservoir overlying a magmatic reservoir with vol% exsolved vapour. Fault-controlled localization of magma constrains potential vent locations for future eruptions. PMID:27447932

  6. Evaluating fault rupture hazard for strike-slip earthquakes

    USGS Publications Warehouse

    Petersen, M.; Cao, T.; Dawson, Tim; Frankel, A.; Wills, C.; Schwartz, D.

    2004-01-01

    We present fault displacement data, regressions, and a methodology to calculate in both a probabilistic and deterministic framework the fault rupture hazard for strike-slip faults. To assess this hazard we consider: (1) the size of the earthquake and probability that it will rupture to the surface, (2) the rate of all potential earthquakes on the fault (3) the distance of the site along and from the mapped fault, (4) the complexity of the fault and quality of the fault mapping, (5) the size of the structure that will be placed at the site, and (6) the potential and size of displacements along or near the fault. Probabilistic fault rupture hazard analysis should be an important consideration in design of structures or lifelines that are located within about 50m of well-mapped active faults.

  7. Lightning Strike Induced Damage Mechanisms of Carbon Fiber Composites

    NASA Astrophysics Data System (ADS)

    Kawakami, Hirohide

    Composite materials have a wide application in aerospace, automotive, and other transportation industries, because of the superior structural and weight performances. Since carbon fiber reinforced polymer composites possess a much lower electrical conductivity as compared to traditional metallic materials utilized for aircraft structures, serious concern about damage resistance/tolerance against lightning has been rising. Main task of this study is to clarify the lightning damage mechanism of carbon fiber reinforced epoxy polymer composites to help further development of lightning strike protection. The research on lightning damage to carbon fiber reinforced polymer composites is quite challenging, and there has been little study available until now. In order to tackle this issue, building block approach was employed. The research was started with the development of supporting technologies such as a current impulse generator to simulate a lightning strike in a laboratory. Then, fundamental electrical properties and fracture behavior of CFRPs exposed to high and low level current impulse were investigated using simple coupon specimens, followed by extensive parametric investigations in terms of different prepreg materials frequently used in aerospace industry, various stacking sequences, different lightning intensity, and lightning current waveforms. It revealed that the thermal resistance capability of polymer matrix was one of the most influential parameters on lightning damage resistance of CFRPs. Based on the experimental findings, the semi-empirical analysis model for predicting the extent of lightning damage was established. The model was fitted through experimental data to determine empirical parameters and, then, showed a good capability to provide reliable predictions for other test conditions and materials. Finally, structural element level lightning tests were performed to explore more practical situations. Specifically, filled-hole CFRP plates and patch

  8. Lightning strike density for the contiguous United States from thunderstorm duration records

    SciTech Connect

    MacGorman, D.R.; Maier, M.W.; Rust, W.D.

    1984-05-01

    An improved lightning ground strike climatology has been obtained from thunderstorm duration data recorded by 450 air weather stations. From lightning strike location data collected in Florida and Oklahoma, it was found that strike density could be estimated from thunderstorm duration by the equation N/sub s/ = 0.054H/sup 1/ /sup 1/, where N/sub s/ is the number of strikes per square kilometer and H is thunderstorm duration in hours. This relationship was applied to thunderstorm duration data from the aviation stations to obtain lightning strike density for the contiguous United States.

  9. Cloud-to-ground strikes to the NASA F-106 airplane

    NASA Technical Reports Server (NTRS)

    Mazur, Vladislav; Fisher, Bruce D.; Brown, Philip W.

    1988-01-01

    Cloud-to-ground (CG) lightning strike data on the NASA F-106B research aircraft obtained during the 1984-86 storm seasons in the vicinity of Wallops Island, Virginia, are analyzed. The results suggest that CG strikes may represent a significant portion of the total number of lightning strikes encountered by the aircraft at altitudes below 6 km. It is unlikely that an aircraft encounters the first return stroke of the CG flash. The current values of the CG strikes are not different from currents in other types of strikes.

  10. Precision Strike Training in Lean Manufacturing: A Workplace Literacy Guidebook [and] Final Report on Precision Strike Workplace Literacy Training at CertainTeed Corporation.

    ERIC Educational Resources Information Center

    National Alliance of Business, Inc., Washington, DC.

    CertainTeed's Precision Strike training program was designed to close the gaps between the current status of its workplace and where that work force needed to be to compete successfully in global markets. Precision Strike included Skills and Knowledge in Lifelong Learning (SKILL) customized, computerized lessons in basic skills, one-on-one…

  11. Analysis of electromagnetic fields on an F-106B aircraft during lightning strikes

    NASA Technical Reports Server (NTRS)

    Trost, T. F.; Pitts, F. L.

    1982-01-01

    Information on the exterior electromagnetic environment of an aircraft when it is struck by lightning has been obtained during thunderstorm penetrations with an F-106B aircraft. Electric and magnetic fields were observed, using mainly time-derivative type sensors, with bandwidths to 50 MHz. Lightning pulse lengths ranging from 25 ns to 7 microsec have been recorded. Sufficient high-frequency content was present to excite electromagnetic resonances of the aircraft, and peaks in the frequency spectra of the waveforms in the range 7 to 23 MHz are in agreement with the resonant frequencies determined in laboratory scale-model tests. Both positively and negatively charged strikes were experienced, and most of the data suggest low values of peak current.

  12. Prevalence of HIV-1 Subtypes and Drug Resistance-Associated Mutations in HIV-1-Positive Treatment-Naive Pregnant Women in Pointe Noire, Republic of the Congo (Kento-Mwana Project).

    PubMed

    Bruzzone, Bianca; Saladini, Francesco; Sticchi, Laura; Mayinda Mboungou, Franc A; Barresi, Renata; Caligiuri, Patrizia; Calzi, Anna; Zazzi, Maurizio; Icardi, Giancarlo; Viscoli, Claudio; Bisio, Francesca

    2015-08-01

    The Kento-Mwana project was carried out in Pointe Noire, Republic of the Congo, to prevent mother-to-child HIV-1 transmission. To determine the prevalence of different subtypes and transmitted drug resistance-associated mutations, 95 plasma samples were collected at baseline from HIV-1-positive naive pregnant women enrolled in the project during the years 2005-2008. Full protease and partial reverse transcriptase sequencing was performed and 68/95 (71.6%) samples were successfully sequenced. Major mutations to nucleoside reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, and protease inhibitors were detected in 4/68 (5.9%), 3/68 (4.4%), and 2/68 (2.9%) samples, respectively. Phylogenetic analysis of HIV-1 isolates showed a high prevalence of unique recombinant forms (24/68, 35%), followed by CRF45_cpx (7/68, 10.3%) and subsubtype A3 and subtype G (6/68 each, 8.8%). Although the prevalence of transmitted drug resistance mutations appears to be currently limited, baseline HIV-1 genotyping is highly advisable in conjunction with antiretroviral therapy scale-up in resource-limited settings to optimize treatment and prevent perinatal transmission. PMID:25970260

  13. Stress triggering of the great Indian Ocean strike-slip earthquakes in a diffuse plate boundary zone

    NASA Astrophysics Data System (ADS)

    Wiseman, Kelly; Bürgmann, Roland

    2012-11-01

    On April 11, 2012, two great magnitude 8+ earthquakes occurred within a two-hour period off the west coast of northern Sumatra, Indonesia, in the broadly distributed India-Australia plate boundary zone. The magnitude 8.6 mainshock holds the distinction of being both the largest instrumentally recorded strike-slip earthquake and the largest earthquake away from a recognized plate boundary fault. The mainshock involved sequential ruptures of multiple fault planes oriented nearly perpendicular to each other. The adjacent 2004 megathrust earthquake statically loaded the northern Wharton Basin oceanic lithosphere on both of the 2012 mainshock fault plane orientations, and greatly enhanced the rate of earthquake activity in the region for a year. Viscoelastic relaxation of the asthenosphere following the 2004 and 2005 megathrust earthquakes continued to positively stress the offshore region, correlating with the locations of later strike-slip earthquakes, including two magnitude 7+ and the 2012 magnitude 8+ earthquakes.

  14. Statistical Correlation between Red Wood Ant Sites and Neotectonic Strike-Slip Faults

    NASA Astrophysics Data System (ADS)

    Berberich, G.; Klimetzek, D.; Wöhler, C.; Grumpe, A.

    2012-04-01

    show a lack of possible fault planes striking between 40 and 90 degrees from north (Deichmann 1990). In addition, a NNW-SSE and NS trending fault system exist. We tested the hypothesis that the spatial distribution of RWA mounds would map the neotectonic stress field directly (Berberich et al. 2012). A statistical method for the automatic extraction of linear patterns from point clouds (Hough transform) was applied to the spatial distribution of RWA mounds. The maxima of the resulting histograms denote the preferential alignment directions. In both cases, it could be clearly shown that the spatial distribution of RWA mounds directly map the main stress field and the conjugated shear system in hierarchically succession. In the West Eifel, RWA depict mainly the opening direction of the Quaternary volcanic field (NW-SE), the WSW-ENE extensional regime and the reactivated Variscan fault systems (NNE-SSW, NE-SW). At the Bodanrück, the hypothesized existence of the NNE-SSW strike-slip fault systems (Büchi & Müller 2003) and additionally NE-SW, NNW-SSE and NS directions could be demonstrated. In conclusion, the statistical analyses show that spatial distribution of RWA maps neotectonic, gaspermeable strike-slip faults. This is especially useful in those cases, where information about the neotectonic regime is incomplete or the resolution by technical means is insufficient.

  15. The Deep Structurs which are Transformed From Strike-slip ones into extending ones and Their Composite evolution of The Southern Segment of Tanlu Fault Belt During Yanshanian stage

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Chen, X.; Zhou, Q.; SinoProbe

    2011-12-01

    The Tan-Lu fault is a well-known active fault belt in eastern Asia. After 40 years of study, a series of important scientific results have been achieved. However, its deep structure, activity history and mechanism still remains in debate. A large quantity of geophysical exploration work has been conducted since late 1990's. This paper focuses on the Jiashan- Lujiang section based on the geophysical exploration, magnetotelluric and magnetic sounding and seismic survey. We find the southern part of the Tan-Lu fault belt can be separated into two parts with different characteristics along the Chihe-Taihu sub-fault. In the east, the Tan-Lu fault belt is composed of several sub-faults with a positive flower structure, characterized by strike-slip in the late Middle Jurassic to early Late Jurassic. In the west, the Tan-Lu fault belt is represented by extensional fracture, made of 3 sub-faults near Dingyuan county. Among them, two sub-faults stretch to the south disappearing in the Hefei basin, one sub-fault, i.e., the Chihe-Taihu sub-fault stretches to the east edge of the Hefei basin, showing a half-graben structure with fault depression occurred in the Early Cretaceous. we establish the evolution model in the Jiashan-Lujiang section with active transforming from strike-slip to extension as well as its relationship between adjacent regions.Our study can be better integration of geological phenomena, interpreting the different views.Our model presents more reasonable explanation for the proposed different points of view on "rift valley hypothesis" and "strike-slip hypothesis". It provides new concept for the further study of the Tan-Lu fault belt.

  16. Surface deformation due to a strike-slip fault in an elastic gravitational layer overlying a viscoelastic gravitational half-space

    SciTech Connect

    Yu, T.T.; Rundle, J.B.; Fernandez, J.

    1996-02-10

    This report discusses crustal surface displacements following a dipping strike-slip faulting using a green function model. The solutions for the elastic-gravitational problem are computed also. A comparison between calculated results and the global positioning system measurement of the Landers earthquake is made.

  17. Acute differences in foot strike and spatiotemporal variables for shod, barefoot or minimalist male runners.

    PubMed

    McCallion, Ciara; Donne, Bernard; Fleming, Neil; Blanksby, Brian

    2014-05-01

    This study compared stride length, stride frequency, contact time, flight time and foot-strike patterns (FSP) when running barefoot, and in minimalist and conventional running shoes. Habitually shod male athletes (n = 14; age 25 ± 6 yr; competitive running experience 8 ± 3 yr) completed a randomised order of 6 by 4-min treadmill runs at velocities (V1 and V2) equivalent to 70 and 85% of best 5-km race time, in the three conditions. Synchronous recording of 3-D joint kinematics and ground reaction force data examined spatiotemporal variables and FSP. Most participants adopted a mid-foot strike pattern, regardless of condition. Heel-toe latency was less at V2 than V1 (-6 ± 20 vs. -1 ± 13 ms, p < 0.05), which indicated a velocity related shift towards a more FFS pattern. Stride duration and flight time, when shod and in minimalist footwear, were greater than barefoot (713 ± 48 and 701 ± 49 vs. 679 ± 56 ms, p < 0.001; and 502 ± 45 and 503 ± 41 vs. 488 ±4 9 ms, p < 0.05, respectively). Contact time was significantly longer when running shod than barefoot or in minimalist footwear (211±30 vs. 191 ± 29 ms and 198 ± 33 ms, p < 0.001). When running barefoot, stride frequency was significantly higher (p < 0.001) than in conventional and minimalist footwear (89 ± 7 vs. 85 ± 6 and 86 ± 6 strides·min(-1)). In conclusion, differences in spatiotemporal variables occurred within a single running session, irrespective of barefoot running experience, and, without a detectable change in FSP. Key pointsDifferences in spatiotemporal variables occurred within a single running session, without a change in foot strike pattern.Stride duration and flight time were greater when shod and in minimalist footwear than when barefoot.Stride frequency when barefoot was higher than when shod or in minimalist footwear.Contact time when shod was longer than when barefoot or in minimalist footwear.Spatiotemporal variables when running in minimalist footwear more closely resemble shod

  18. Acute Differences in Foot Strike and Spatiotemporal Variables for Shod, Barefoot or Minimalist Male Runners

    PubMed Central

    McCallion, Ciara; Donne, Bernard; Fleming, Neil; Blanksby, Brian

    2014-01-01

    This study compared stride length, stride frequency, contact time, flight time and foot-strike patterns (FSP) when running barefoot, and in minimalist and conventional running shoes. Habitually shod male athletes (n = 14; age 25 ± 6 yr; competitive running experience 8 ± 3 yr) completed a randomised order of 6 by 4-min treadmill runs at velocities (V1 and V2) equivalent to 70 and 85% of best 5-km race time, in the three conditions. Synchronous recording of 3-D joint kinematics and ground reaction force data examined spatiotemporal variables and FSP. Most participants adopted a mid-foot strike pattern, regardless of condition. Heel-toe latency was less at V2 than V1 (-6 ± 20 vs. -1 ± 13 ms, p < 0.05), which indicated a velocity related shift towards a more FFS pattern. Stride duration and flight time, when shod and in minimalist footwear, were greater than barefoot (713 ± 48 and 701 ± 49 vs. 679 ± 56 ms, p < 0.001; and 502 ± 45 and 503 ± 41 vs. 488 ±4 9 ms, p < 0.05, respectively). Contact time was significantly longer when running shod than barefoot or in minimalist footwear (211±30 vs. 191 ± 29 ms and 198 ± 33 ms, p < 0.001). When running barefoot, stride frequency was significantly higher (p < 0.001) than in conventional and minimalist footwear (89 ± 7 vs. 85 ± 6 and 86 ± 6 strides·min-1). In conclusion, differences in spatiotemporal variables occurred within a single running session, irrespective of barefoot running experience, and, without a detectable change in FSP. Key points Differences in spatiotemporal variables occurred within a single running session, without a change in foot strike pattern. Stride duration and flight time were greater when shod and in minimalist footwear than when barefoot. Stride frequency when barefoot was higher than when shod or in minimalist footwear. Contact time when shod was longer than when barefoot or in minimalist footwear. Spatiotemporal variables when running in minimalist footwear more closely resemble

  19. Tipping Point

    MedlinePlus Videos and Cool Tools

    ... Tipping Point by CPSC Blogger September 22 appliance child Childproofing CPSC danger death electrical fall furniture head ... TV falls with about the same force as child falling from the third story of a building. ...

  20. Chemically striking regions on Mars and Stealth revisited

    NASA Astrophysics Data System (ADS)

    Karunatillake, Suniti; Wray, James J.; Squyres, Steven W.; Taylor, G. Jeffrey; Gasnault, Olivier; McLennan, Scott M.; Boynton, William; El Maarry, M. R.; Dohm, James M.

    2009-12-01

    The Mars Odyssey Gamma Ray Spectrometer Suite has yielded global chemical information for Mars. In this work, we establish regions of unusual chemical composition relative to average Mars primarily on the basis of Ca, Cl, Fe, H, K, Si, and Th. Using data from Mars Odyssey; the Mars Exploration Rovers; the Mars Reconnaissance Orbiter Imaging; and 3.5 cm and 1.35 cm radar observations from Earth, we examine a chemically striking ≈2.E6 km2 region and find it to overlap significantly with a radar Stealth region on Mars. It is remarkably enriched in Cl and depleted in Fe and Si (along with minor variations in H, K, and Th) relative to average Mars. Surface dust observed at the two rover sites mixed with and indurated by Ca/Mg-bearing sulfate salts would be a reasonable chemical and physical analog to meter-scale depths. We describe potential scenarios that may have contributed to the unique properties of this region. The bulk dust component may be an air fall deposit of compositionally uniform dust as observed in situ. Hydrothermal acid fog reactions on the flanks of nearby volcanoes may have generated sulfates with subsequent deflation and transport. Alternatively, sulfates may have been produced by low-temperature, regional-scale activity of ground ice-driven brine and/or regional-scale deposition of acidified H2O snowfall.

  1. Striking a balance between professionalism and strict adherence to procedures

    SciTech Connect

    Leckner, J.M. ); Ghertman, F.

    1991-11-01

    It is frequently a delicate matter to strike the correct balance between reliance on the professionalism of an operating staff and the enforcement of strict procedures. At French nuclear facilities, the initial approach was to use procedures to ensure that instructions were strictly adhered to. A review of incident and accident procedures resulted in restructuring documents to organize operator action. As to general operating procedures in which more initiative is left to those involved the format of the documents and the way that they are arranged has scarcely changed since they were first issued. The trend has been to try to make the documents comprehensive, resulting in a considerable increase in their size and making it increasingly difficult to use them. As the nature of the documents has been the origin of numerous accidents (failure to comply with the documents, erroneous action, and operating incidents), the authors decided to review the form and content of the operating documents to determine what should be covered by rules and what should be left to the operator in terms of responsibility and freedom of action. It is in this perspective, at the request of Golfech power plant and with the participation of the operating department engineers and technicians, that the authors have tried to restructure radioactive release effluent management procedures.

  2. The assessment of lethal propeller strike injuries in sea mammals.

    PubMed

    Byard, Roger W; Winskog, Calle; Machado, Aaron; Boardman, Wayne

    2012-04-01

    Assessment of injuries in marine mammals may be required to help authorities determine whether human activity was involved. Three cases of marine animal deaths involving propeller blade strikes are reported to demonstrate characteristic features of such cases and diagnostic difficulties that may occur. Case 1: A juvenile New Zealand fur seal (Arctocephalus forsteri) suffered two parallel linear incised wounds of the flank and died following small intestinal herniation. Case 2: An Indo-Pacific bottlenose dolphin neonate (Tursiops aduncus) died from a deeply incised wound of the left side of the head with shattering of the skull and laceration of the underlying brain.Case 3: An adult female Indo-Pacific bottlenose dolphin (T. aduncus) died from two parallel chop wounds to the torso with opening of the thoracic and abdominal cavities with fractures of the ribs and vertebrae. Given that some animals may recover, and that the carcasses of those that are killed may simply not be found or reported, it is impossible to provide an estimate of the incidence of this type of injury amongst wild sea mammals. In cases that do come to forensic attention accurate evaluation of the type of injury may potentially have great medicolegal significance. Post-mortem putrefaction and post-mortem feeding by other sea animals may complicate assessments. PMID:22391002

  3. An inward striking free reed coupled to a cylindrical pipe

    NASA Astrophysics Data System (ADS)

    Vines, Justin; Paquette, Ammon; Cottingham, James P.

    2003-10-01

    A number of acoustical measurements have made on a reed-pipe combination consisting of a harmonium-type reed from an American reed organ installed at the closed end of a cylindrical pipe. This configuration, which somewhat resembles the configuration of free-reed organ pipes, differs from the reed-pipe combination occurring in the mouth organs of Asia, which use symmetric (outward striking) free reeds and normally operate on both possible directions of airflow. Measurements have been made of the sounding frequency, amplitude of vibration of the reed tongue, and the sound spectrum. Of particular interest is the degree to which the reed frequency can be altered by altering the pipe length, and hence the pipe resonance frequency. In this case the sounding frequency can be pulled considerably below the natural frequency of the reed. These results can be compared with the results of similar measurements on free-reed organ pipes [J. Braasch, C. Ahrens, J. P. Cottingham, and T. D. Rossing, Fortschr. Akust., DAGA (2000)]. In addition, some interesting ``special effects'' have been studied, which can be obtained using unusual pipe lengths and blowing in the ``wrong'' direction. [Work supported by the NSF from REU Grant No. 0139096.

  4. The geometries and development of late orogenic strike-slip faults

    NASA Astrophysics Data System (ADS)

    Anderson, M. W.; Peacock, D. C. P.

    2003-04-01

    Strike-slip faults are commonly the final phase of contraction in orogenic belts, occurring when the folds have locked-up and the thrusts have become too steep for further displacement to occur. Where the maximum stress axis (sigma1) is perpendicular to the orogenic belt (i.e. pure shear), the strike-slip faults are conjugate and represent strike-perpendicular shortening and necessary strike-parallel extension. An example of such behaviour occurs in the steeply dipping Silurian sandstones and shales in Kirkcudbrightshire, in the Southern Uplands of Scotland. If sigma1 is at ~ 70°; to the strike of the orogenic belt, the conjugate strike-slip faults become asymmetric. One set of strike-slip faults occurs at a high angle to the strike of bedding, and the conjugate set has a ramp-flat trajectory across steeply dipping beds. An example of this behaviour occurs in the steeply dipping Silurian turbidites at Ardglass, in the Longford-Down terrane of Northern Ireland. If sigma1 is at a lower angle to the orogenic belt (i.e. transpression), one set of strike-slip faults tends to dominate. In some cases, the dominant strike-slip fault set is parallel to the strike of the orogenic belt, the Caledonian-age Great Glen Fault of Scotland being such an example. In other cases, block rotation occurs on the set of strike-slip faults that are at a high angle to the orogenic belt, as in the Variscan Orogenic Belt of SW England. An annulus model is presented to illustrate the variations in geometries of late-orogenic strike-slip faults from pure shear to transpression.

  5. Changes of static stress and aftershocks distribution for the strike-slip earthquakes in the West Pilippine Sea Plate

    NASA Astrophysics Data System (ADS)

    Lin, Y.; Lin, J.

    2013-12-01

    Over the last few decades, several strike-slip type earthquakes have been observed within the West Philippine Sea Plate (WPSP), to the east of the Gagua Ridge area. Nearly all of these earthquakes possessed a similar focal mechanism pattern with one fault plane sub-parallel to approximately N35°E. Based on bathymetric and magnetic anomaly data, several obvious NE-SW ancient fracture zones have been identified in the WPSP and considered to be the main rupture plane of these strike-slip earthquakes. However, the aftershocks distributions of these strike-slip earthquakes show NW-SE trending pattern, which is almost in orthogonal with the fracture zones orientation. Thus, the real rupture plane of these events is still undetermined. Otherwise, many researches have provided evidence that stress increase promotes seismicity: the increase of static Coulomb stress is generally correlated to the high occurrence of aftershocks. In our study, we chose three large earthquakes occurred in the WPSP to analyze the relationship between static Coulomb stress changes and seismicity rate changes, in the aim of determining an appropriate rupture plane for these strike-slip events. In our analysis, two fault planes have been used to estimate the static Coulomb stress change. Then, we compared the aftershocks distribution with the Coulomb stress distribution pattern. Our results shows that when the fault plane is trending NW-SE direction, the aftershocks occurred in the region with positive Coulomb stress changes, while the seismicity was decreased in the region of negative Coulomb stress changes. Otherwise, the other fault plane could not at all explain the observed aftershocks distribution. Consequently, the NW-SE fault plane is the preferred rupture plane for the strike-slip events occurred in the WPSP. The 11 April 2012, Mw 8.6 and Mw 8.2 earthquakes occurred off the west coast of northern Sumatra, Indonesia, are also strike-slip fault events within the Indo-Australia plate. These

  6. A tectonic interpretation of NW-SE strike-slip faulting during the 2004 off the Kii peninsula earthquakes, Japan: Probable tear of the Philippine Sea plate

    NASA Astrophysics Data System (ADS)

    Miyoshi, T.; Ishibashi, K.

    2005-11-01

    The 2004 off the Kii peninsula earthquakes (Mw 7.5 for the main shock) occurred within the subducting Philippine Sea (PHS) plate near its boundary, the Nankai trough, southwest Japan. The rupture mode of the foreshock-main shock-aftershock sequence was complicated, a combination of ENE-WSW striking (almost trough parallel) reverse faulting beneath the trough and NW-SE trending (almost trough normal) strike-slip faulting mostly on the landward side of the former. In this paper, we discuss the tectonic meaning of this NW-SE running strike-slip fault. We examined hypocenter distribution and focal mechanisms of slab earthquakes from October 1997 through September 2004 and confirmed a NW-SE striking tear of the PHS slab beneath the middle part of the Kii Peninsula pointed out by Miyoshi and Ishibashi (2004). According to the Earthquake Research Committee (2004) there is a NW-SE trending structural discontinuity in the PHS crust to the southeast of the main shock epicenter. Putting all features together, we interpret that there is a NW-SE striking fracture within the PHS plate continuously from the Nankai trough region to the slab beneath the Kii Peninsula, and that a partial rupture of this fracture occurred during the off the Kii peninsula earthquakes together with trough-parallel reverse faulting. It should be noted that two disastrous M 7-class slab earthquakes seem to have occurred along this tear beneath the peninsula in 1899 and 1952.

  7. Experimental and numerical study of a bird strike against a windshield

    NASA Astrophysics Data System (ADS)

    Plassard, Fabien; Hereil, Pierre-Louis; Joseph, Pierric; Mespoulet, Jérôme

    2015-09-01

    This paper describes a bird strike study performed at THIOT-INGENIERIE laboratory. For aeronautic requirements, the 220 mm version of the gas gun TITAN is used to perform bird strike on instrumented structures. This paper shows a bird strike on a polycarbonate windshield instrumented with high speed cameras, velocity and force sensors. A crossed work with numerical simulation has been performed to design target support and diagnostic tools. It permits also to demonstrate reliability of the numerical tools.

  8. Strike-slip faulting of ridged plains near Valles Marineris, Mars

    NASA Technical Reports Server (NTRS)

    Schultz, Richard A.

    1989-01-01

    This paper identifies and documents several well-preserved examples of Martian strike-slip faults and examines their relationships to wrinkle-ridges. The strike-slip faulting predates or overlaps periods of wrinkle-ridge growth southeast of Valles Marineris, and some wrinkle ridges may have nucleated and grown as a result of strike-slip displacements along the echelon fault arrays. Lateral displacements of several km inferred along these arrays may be related to tectonism in Tharsis.

  9. Paleogene tectonics and forearc strike-slip faulting: southern Chile

    SciTech Connect

    Leslie, R.B.; Cande, S.C.

    1985-01-01

    Several lines of evidence suggest that highly oblique Nazca-South America convergence during the middle to late Paleogene resulted in the development of a dextral strike-slip fault landward of the Chile trench. The Linquine-Ofqui fault (LOF) is nearly 1000 km long and trends approximately N10/sup 0/E between 39/sup 0/S and 47/sup 0/S. It consists of several fault strands with the dominant strand represented by a mylonitic zone approximately 3 km wide. Preliminary field mapping (Herve, 1984) indicates seaward trending splay faults that can be projected offshore in the vicinity of two large embayments along the Chile margin. The Golfo de Guafo embayment occurs between 43/sup 0/S and 44/sup 0/S and is approx.40 km wide in the N-S direction. The Golfo de Penas embayment is approx.75 km wide in the N-S direction and occurs between 47/sup 0/S and 48/sup 0/S at the southern end of the LOF. The authors suggest that these embayments are a consequence of NE-SW extension due to movement on splay faults of the LOF system during the middle to late Paleogene. Convergence during this time was highly oblique. Movement decreased on the northern portion of the LOF prior to a decrease in movement on the southern end. Radiometric dates on rocks from the fault zone (Herve, 1984) provide constraints on the timing of movement along the fault. Marine geophysical data allow you to map the structures in these embayments which support the model of dextral shear along the LOF. Reactivation of the LOF may have occurred 6 Ma when a segment of the actively spreading Chile ridge was subducted at the Chile trench adjacent to the Golfo de Penas.

  10. Fault displacement hazard for strike-slip faults

    USGS Publications Warehouse

    Petersen, M.D.; Dawson, T.E.; Chen, R.; Cao, T.; Wills, C.J.; Schwartz, D.P.; Frankel, A.D.

    2011-01-01

    In this paper we present a methodology, data, and regression equations for calculating the fault rupture hazard at sites near steeply dipping, strike-slip faults. We collected and digitized on-fault and off-fault displacement data for 9 global strikeslip earthquakes ranging from moment magnitude M 6.5 to M 7.6 and supplemented these with displacements from 13 global earthquakes compiled byWesnousky (2008), who considers events up to M 7.9. Displacements on the primary fault fall off at the rupture ends and are often measured in meters, while displacements on secondary (offfault) or distributed faults may measure a few centimeters up to more than a meter and decay with distance from the rupture. Probability of earthquake rupture is less than 15% for cells 200 m??200 m and is less than 2% for 25 m??25 m cells at distances greater than 200mfrom the primary-fault rupture. Therefore, the hazard for off-fault ruptures is much lower than the hazard near the fault. Our data indicate that rupture displacements up to 35cm can be triggered on adjacent faults at distances out to 10kmor more from the primary-fault rupture. An example calculation shows that, for an active fault which has repeated large earthquakes every few hundred years, fault rupture hazard analysis should be an important consideration in the design of structures or lifelines that are located near the principal fault, within about 150 m of well-mapped active faults with a simple trace and within 300 m of faults with poorly defined or complex traces.

  11. Assessment of performing an MST strike in Tank 21H

    SciTech Connect

    Poirier, Michael R.

    2014-09-29

    Previous Savannah River National Laboratory (SRNL) tank mixing studies performed for the Small Column Ion Exchange (SCIX) project have shown that 3 Submersible Mixer Pumps (SMPs) installed in Tank 41 are sufficient to support actinide removal by MST sorption as well as subsequent resuspension and removal of settled solids. Savannah River Remediation (SRR) is pursuing MST addition into Tank 21 as part of the Large Tank Strike (LTS) project. The preliminary scope for LTS involves the use of three standard slurry pumps (installed in N, SE, and SW risers) in a Type IV tank. Due to the differences in tank size, internal interferences, and pump design, a separate mixing evaluation is required to determine if the proposed configuration will allow for MST suspension and strontium and actinide sorption. The author performed the analysis by reviewing drawings for Tank 21 [W231023] and determining the required cleaning radius or zone of influence for the pumps. This requirement was compared with previous pilot-scale MST suspension data collected for SCIX that determined the cleaning radius, or zone of influence, as a function of pump operating parameters. The author also reviewed a previous Tank 50 mixing analysis that examined the ability of standard slurry pumps to suspend sludge particles. Based on a review of the pilot-scale SCIX mixing tests and Tank 50 pump operating experience, three standard slurry pumps should be able to suspend sludge and MST to effectively sorb strontium and actinides onto the MST. Using the SCIX data requires an assumption about the impact of cooling coils on slurry pump mixing. The basis for this assumption is described in this report. Using the Tank 50 operating experience shows three standard slurry pumps should be able to suspend solids if the shear strength of the settled solids is less than 160 Pa. Because Tank 21 does not contain cooling coils, the shear strength could be larger.

  12. Along-Strike and Down-Dip Variations in Subduction Zone Slip Deficit: Persistent or Transient? (Invited)

    NASA Astrophysics Data System (ADS)

    Freymueller, J. T.

    2010-12-01

    The pattern of elastic deformation at subduction zones depends on the along-strike and down-dip variation in the slip deficit on the plate interface. The location and magnitude of contractional strain is controlled mainly by the down-dip transition from locked (high slip rate deficit) to creeping (low slip rate deficit) behavior of the interface. In southern Alaska, there are dramatic along-strike variations in the depth of this transition, including segments where the locked region is more than 150-200 km wide and at least one segment that may be creeping continuously at all depths. Is this pattern is persistent over time, or does it vary substantially with time? The along-strike variations appear to be persistent over the geodetic record (only 10-15 years), and also with the record of slip in great subduction earthquakes (decades to centuries). In contrast, variations in the position of the downdip transition are observed over short timescales. A large slow-slip events in the upper Cook Inlet region occurred from 1998-2001, during which part of the interface that previously had been locked began to creep in slow slip. More recently, the opposite situation has occurred in lower Cook Inlet, near the town of Homer. Since approximately 2004, part of the interface that had been creeping has locked, making the locked zone wider than before (but still narrower than in the neighboring segments along strike). Other changes in the pattern of deformation here may have occurred in the mid-1990s, based on sparse data. Perhaps the period mid-1990s through 2004 represented a very long slow slip event, or perhaps the frictional behavior of the interface at the down-dip end of the locked zone is very sensitive to small stress changes.

  13. The distribution and characterization of strike-slip faults on Enceladus

    NASA Astrophysics Data System (ADS)

    Martin, Emily S.

    2016-03-01

    Strike-slip faulting is typically characterized by lateral offsets on icy satellites of the outer solar system. However, strike-slip faults on Enceladus lack these typical lateral offsets and instead are marked by the presence of tailcracks or en echelon cracks. These features are used here to develop the first near-global distribution of strike-slip faults on Enceladus. Strike-slip faults on Enceladus fall into three broad categories: tectonic terrain boundaries, reactivated linear features, and primary strike-slip faults. All three types of strike-slip faults are found predominantly, or within close proximity to, the antipodal cratered terrains on the Saturnian and anti-Saturnian hemispheres. Stress modeling suggests that strike-slip faulting on Enceladus is not controlled by nonsynchronous rotation, as on Europa, suggesting a fundamentally different process driving Enceladus's strike-slip faulting. The motion along strike-slip faults at tectonic terrain boundaries suggests large-scale northward migration of the ice shell on the leading hemisphere of Enceladus, occurring perpendicular to the opening direction of the tiger stripes in the south polar terrain.

  14. Automatic resolution of the three-points geological problem

    NASA Astrophysics Data System (ADS)

    Martinez-Torres, Luis M.; Lopetegui, Ane; Eguiluz, Luis

    2012-05-01

    The problem of three points, or 3P problem, is the basic geometrical reference of numerous geological structures. We propose a simple Microsoft Excel spreadsheet program that determines from three georeferenced points the strike and dip of the plane that contains them. Practical examples showing the application in Google Earth and LIDAR data are presented.

  15. Strike-parallel and strike-normal coordinate system around geometrically complicated rupture traces: use by NGA-West2 and further improvements

    USGS Publications Warehouse

    Spudich, Paul A.; Chiou, Brian

    2015-01-01

    We present a two-dimensional system of generalized coordinates for use with geometrically complex fault ruptures that are neither straight nor continuous. The coordinates are a generalization of the conventional strike-normal and strike-parallel coordinates of a single straight fault. The presented conventions and formulations are applicable to a single curved trace, as well as multiple traces representing the rupture of branching faults or noncontiguous faults. An early application of our generalized system is in the second round of the Next Generation of Ground-Motion Attenuation Model project for the Western United States (NGA-West2), where they were used in the characterization of the hanging-wall effects. We further improve the NGA-West2 strike-parallel formulation for multiple rupture traces with a more intuitive definition of the nominal strike direction. We also derive an analytical expression for the gradient of the generalized strike-normal coordinate. The direction of this gradient may be used as the strike-normal direction in the study of polarization effects on ground motions.

  16. Optical Pointing Sensor

    NASA Technical Reports Server (NTRS)

    Shields, Joel F.; Metz, Brandon C.

    2010-01-01

    The optical pointing sensor provides a means of directly measuring the relative positions of JPL s Formation Control Testbed (FCT) vehicles without communication. This innovation is a steerable infrared (IR) rangefinder that gives measurements in terms of range and bearing to a passive retroreflector.

  17. The Lagrange Points

    ERIC Educational Resources Information Center

    Lovell, M.S.

    2007-01-01

    This paper presents a derivation of all five Lagrange points by methods accessible to sixth-form students, and provides a further opportunity to match Newtonian gravity with centripetal force. The predictive powers of good scientific theories are also discussed with regard to the philosophy of science. Methods for calculating the positions of the…

  18. Strike Four! Do-Over Policies Institutionalize GPA Distortion

    ERIC Educational Resources Information Center

    Marx, Jonathan; Meeler, David

    2013-01-01

    Purpose: The aim of this paper is to illustrate how universities play an institutional role in inflating student grade point averages (GPA) by modifying academic polices such as course withdraw, repeats, and satisfactory/unsatisfactory grade options. Design/methodology/approach: Three research strategies are employed: an examination of eight…

  19. Squeezing, Striking, and Vocalizing: Is Number Representation Fundamentally Spatial?

    ERIC Educational Resources Information Center

    Nunez, Rafael; Doan, D.; Nikoulina, Anastasia

    2011-01-01

    Numbers are fundamental entities in mathematics, but their cognitive bases are unclear. Abundant research points to linear space as a natural grounding for number representation. But, is number representation fundamentally spatial? We disentangle number representation from standard number-to-line reporting methods, and compare numerical…

  20. A preliminary study on surface ground deformation near shallow foundation induced by strike-slip faulting

    NASA Astrophysics Data System (ADS)

    Wong, Pei-Syuan; Lin, Ming-Lang

    2016-04-01

    According to investigation of recent earthquakes, ground deformation and surface rupture are used to map the influenced range of the active fault. The zones of horizontal and vertical surface displacements and different features of surface rupture are investigated in the field, for example, the Greendale Fault 2010, MW 7.1 Canterbury earthquake. The buildings near the fault rotated and displaced vertically and horizontally due to the ground deformation. Besides, the propagation of fault trace detoured them because of the higher rigidity. Consequently, it's necessary to explore the ground deformation and mechanism of the foundation induced by strike-slip faulting for the safety issue. Based on previous study from scaled analogue model of strike-slip faulting, the ground deformation is controlled by material properties, depth of soil, and boundary condition. On the condition controlled, the model shows the features of ground deformation in the field. This study presents results from shear box experiment on small-scale soft clay models subjected to strike-slip faulting and placed shallow foundations on it in a 1-g environment. The quantifiable data including sequence of surface rupture, topography and the position of foundation are recorded with increasing faulting. From the result of the experiment, first en echelon R shears appeared. The R shears rotated to a more parallel angle to the trace and cracks pulled apart along them with increasing displacements. Then the P shears crossed the basement fault in the opposite direction appears and linked R shears. Lastly the central shear was Y shears. On the other hand, the development of wider zones of rupture, higher rising surface and larger the crack area on surface developed, with deeper depth of soil. With the depth of 1 cm and half-box displacement 1.2 cm, en echelon R shears appeared and the surface above the fault trace elevated to 1.15 mm (Dv), causing a 1.16 cm-wide zone of ground-surface rupture and deformation

  1. Pre/post-strike atmospheric assessment system (PAAS)

    SciTech Connect

    Peglow, S. G., LLNL; Molitoris, J. D., LLNL

    1997-02-03

    The Pre/Post-Strike Atmospheric Assessment System was proposed to show the importance of local meteorological conditions in the vicinity of a site suspected of storing or producing toxic agents and demonstrate a technology to measure these conditions, specifically wind fields. The ability to predict the collateral effects resulting from an attack on a facility containing hazardous materials is crucial to conducting effective military operations. Our study approach utilized a combination of field measurements with dispersion modeling to better understand which variables in terrain and weather were most important to collateral damage predictions. To develop the PAAS wind-sensing technology, we utilized a combination of emergent and available technology from micro-Doppler and highly coherent laser systems. The method used for wind sensing is to probe the atmosphere with a highly coherent laser beam. As the beam probes, light is back-scattered from particles entrained in the air to the lidar transceiver and detected by the instrument. Any motion of the aerosols with a component along the beam axis leads to a Doppler shift of the received light. Scanning in a conical fashion about the zenith results in a more accurate and two-dimensional measurement of the wind velocity. The major milestones in the benchtop system development were to verify the design by demonstrating the technique in the laboratory, then scale the design down to a size consistent with a demonstrator unit which could be built to take data in the field. The micro-Doppler heterodyne system we developed determines absolute motion by optically mixing a reference beam with the return signal and has shown motion sensitivity to better than 1 cm/s. This report describes the rationale, technical approach and laboratory testing undertaken to demonstrate the feasibility and utility of a system to provide local meteorological data and predict atmospheric particulate motion. The work described herein was funded by

  2. Shallow Hydrothermal Flow in a Strike-Slip Fault System, Mt Isa, Australia: A Proterozoic Analog for Modern Geothermal Systems Along Strike-Slip Faults

    NASA Astrophysics Data System (ADS)

    Sibson, R. H.; Ghisetti, F.; Begbie, M.

    2014-12-01

    Strong E-W shortening during the Isan Orogeny (1590-1500 Ma) led to crustal thickening and compressional inversion of former intracontinental rift basins. The resulting metamorphic/plutonic basement complex is disrupted by conjugate, mutually cross-cutting sets of brittle, late-orogenic strike-slip faults. Dextral strike-slip faults (separations < 25 km) strike NE-NNE, while conjugate sinistral faults strike SE-SSE, defining a wrench regime (σv = σ2) with horizontal maximum compression, σ1, trending c. 100°. The strike-slip faults are recessive except in dilational sites where upwelling hydrothermal fluids have silicified the cataclastic shear zones (CSZ) which protrude as blade-like ridges extending for kilometres across the semi-arid terrain. The mineralized fault segments include sinuous releasing bends where the fault trace is deflected <10° as well as more abrupt dilational stepovers with distributed extension fracturing linking en echelon fault segments. Other components of structural permeability include: (1) innumerable fault-parallel quartz-veins (cm to m thickness) within the CSZ; (2) irregular stringer veins; and (3) a regional set of predominantly extensional, subvertical planar quartz veins oriented 080-120° at moderate angles to the main faults. Broad contemporaneity is indicated by mutual cross-cutting relationships between all structural components. Measured strike separations along shear fractures are consistent with seismic slip increments which refreshed fracture permeability and promoted hydrothermal flow. Textures suggest the faults were exhumed from epithermal boiling environments (<1-2 km depth). Restoration of fault cohesive strength by hydrothermal cementation was critical in allowing continued vein formation by hydraulic extension fracturing. The distribution of hydrothermal quartz within the fault system provides a guide to structural localization of upflow zones in geothermal fields developed along strike-slip faults.

  3. Wisdom-Centered Learning: Striking a New Paradigm for Education.

    ERIC Educational Resources Information Center

    Wilson, Kenneth G.

    1994-01-01

    Introduces an education reform model featuring 2 positive feedback loops: a 20-year apprenticeship system for teachers; and a continuous improvement system for classroom materials, curriculum, professional development, and classroom assessment. Continuing teacher education would emphasize deeper understanding of subject matter, mastery of improved…

  4. National Security and Civil Liberty: Striking the Balance

    ERIC Educational Resources Information Center

    Lopach, James J.; Luckowski, Jean A.

    2006-01-01

    After September 11, 2001, the Bush administration initiated large-scale electronic surveillance within the United States to gather intelligence to protect citizens from terrorists. Media commentary, public reaction, and classroom practices regarding this program have tended toward either-or positions: either for presidential power and national…

  5. Motion to strike claim dismissed in HIV defamation suit.

    PubMed

    Gold, J; Elliott, R

    2001-01-01

    On 23 April 2001, the Ontario Superior Court of Justice issued the first Canadian ruling on the issue of whether words inputing that a person is HIV-positive or has AIDS can be the basis of a defamation action per se, in the case of Serdar v Metroland Printing, Publishing and Distributing Ltd. PMID:11837012

  6. The Sudbury School Strike--The Effect on Students One Year After.

    ERIC Educational Resources Information Center

    Wilkinson, Derek

    1989-01-01

    Results are reported from a study that attempted to find the objective effects of a 3-month high school teachers' strike on 134 first year university students. Findings indicate that no important differences existed between strike students and others with regard to grades, failures, or withdrawals. (IAH)

  7. Factors affecting defensive strike behavior in Brown Treesnakes (Boiga irregularis) provoked by humans

    USGS Publications Warehouse

    Spencer, McKayka M.; Lardner, Bjorn; Mazurek, M.J.; Reed, Robert N.

    2015-01-01

    Striking is a typical antipredator defense exhibited by many species of snakes. While trapping Brown Treesnakes (Boiga irregularis) on Guam, we observed that snakes most frequently struck at an approaching person at a site where snakes had been trapped, marked, and handled in the past. Using a combination of between-sites and within-site comparisons, we assessed if the propensity to strike was correlated with capture histories (both recent and long-term), snake size, body condition (a proxy to nutritional stress), sex, or tail condition (broken or intact), while controlling for confounding variables. We confirmed that propensity to strike was higher at the site where we had been conducting capture-mark-recapture for several years. However, we were unable to demonstrate a correlation between striking tendencies and individual recent or long-term capture histories. The only morphological covariate that had an effect on strike propensity was sex, with females striking more often than males. After removing the site effect from our model, we found that snakes missing parts of their tails were more likely to strike than snakes with intact tails. We have yet to identify the factor(s) that cause the pronounced difference across sites in snake propensity to strike, and data from additional sites might help elucidate any geographical patterns.

  8. Effects of Foot Strike and Step Frequency on Achilles Tendon Stress During Running.

    PubMed

    Lyght, Michael; Nockerts, Matthew; Kernozek, Thomas W; Ragan, Robert

    2016-08-01

    Achilles tendon (AT) injuries are common in runners. The AT withstands high magnitudes of stress during running which may contribute to injury. Our purpose was to examine the effects of foot strike pattern and step frequency on AT stress and strain during running utilizing muscle forces based on a musculoskeletal model and subject-specific ultrasound-derived AT cross-sectional area. Nineteen female runners performed running trials under 6 conditions, including rearfoot strike and forefoot strike patterns at their preferred cadence, +5%, and -5% preferred cadence. Rearfoot strike patterns had less peak AT stress (P < .001), strain (P < .001), and strain rate (P < .001) compared with the forefoot strike pattern. A reduction in peak AT stress and strain were exhibited with a +5% preferred step frequency relative to the preferred condition using a rearfoot (P < .001) and forefoot (P=.005) strike pattern. Strain rate was not different (P > .05) between step frequencies within each foot strike condition. Our results suggest that a rearfoot pattern may reduce AT stress, strain, and strain rate. Increases in step frequency of 5% above preferred frequency, regardless of foot strike pattern, may also lower peak AT stress and strain. PMID:26955843

  9. The 1981 direct strike lightning data. [utilizing the F-106 aircraft

    NASA Technical Reports Server (NTRS)

    Pitts, F. L.; Thomas, M. E.

    1982-01-01

    Data waveforms obtained during the 1981 direct strike lightning tests, utilizing the NASA F-106B aircraft specially instrumented for lightning electromagnetic measurements are presented. The aircraft was operated in a thunderstorm environment to elicit strikes. Electromagnetic field data were recorded for both attached lightning and free field excitation of the aircraft.

  10. Variation in Foot Strike Patterns among Habitually Barefoot and Shod Runners in Kenya

    PubMed Central

    Lieberman, Daniel E.; Castillo, Eric R.; Otarola-Castillo, Erik; Sang, Meshack K.; Sigei, Timothy K.; Ojiambo, Robert; Okutoyi, Paul; Pitsiladis, Yannis

    2015-01-01

    Runners are often categorized as forefoot, midfoot or rearfoot strikers, but how much and why do individuals vary in foot strike patterns when running on level terrain? This study used general linear mixed-effects models to explore both intra- and inter-individual variations in foot strike pattern among 48 Kalenjin-speaking participants from Kenya who varied in age, sex, body mass, height, running history, and habitual use of footwear. High speed video was used to measure lower extremity kinematics at ground contact in the sagittal plane while participants ran down 13 meter-long tracks with three variables independently controlled: speed, track stiffness, and step frequency. 72% of the habitually barefoot and 32% of the habitually shod participants used multiple strike types, with significantly higher levels of foot strike variation among individuals who ran less frequently and who used lower step frequencies. There was no effect of sex, age, height or weight on foot strike angle, but individuals were more likely to midfoot or forefoot strike when they ran on a stiff surface, had a high preferred stride frequency, were habitually barefoot, and had more experience running. It is hypothesized that strike type variation during running, including a more frequent use of forefoot and midfoot strikes, used to be greater before the introduction of cushioned shoes and paved surfaces. PMID:26154285

  11. Labor Conflict on the National Stage: Metaphoric Lenses in Israel's Teachers' Strike

    ERIC Educational Resources Information Center

    Shenkar, Miriam; Shenkar, Oded

    2011-01-01

    Teachers often embed their labor demands within a broader context to claim high moral ground and build community support. We analyze a recent teachers' strike in Israel, looking at how the strike played out in a country where the challenges of globalization collided with a socialist legacy in the face of an existential threat. The analysis reveals…

  12. Teacher Strikes, Work Stoppages, and Interruptions of Service, 1969-70. NEA Research Memo.

    ERIC Educational Resources Information Center

    Brant, Elizabeth

    The information in this report reveals that an estimated 118,000 teachers participated in strike action and that an estimated 911,000 man-days of instruction were involved in work stoppages that varied in duration from one-half day to 23 days. Tables provide data on (1) man-days involved; (2) strikes and work stoppages by organization, month, and…

  13. Teacher Strikes, Work Stoppages, and Interruptions of Service, 1970-71. NEA Research Memo.

    ERIC Educational Resources Information Center

    Covington, Richard

    The information in this report reveals that an estimated 89,651 teachers participated in strike action and that an estimated 717,217 man-days of instruction were involved in work stoppages that varied in duration from one day to 12 weeks. Tables provide data on (1) man-days involved; (2) strikes and work stoppages by organization, month, and…

  14. Variation in Foot Strike Patterns among Habitually Barefoot and Shod Runners in Kenya.

    PubMed

    Lieberman, Daniel E; Castillo, Eric R; Otarola-Castillo, Erik; Sang, Meshack K; Sigei, Timothy K; Ojiambo, Robert; Okutoyi, Paul; Pitsiladis, Yannis

    2015-01-01

    Runners are often categorized as forefoot, midfoot or rearfoot strikers, but how much and why do individuals vary in foot strike patterns when running on level terrain? This study used general linear mixed-effects models to explore both intra- and inter-individual variations in foot strike pattern among 48 Kalenjin-speaking participants from Kenya who varied in age, sex, body mass, height, running history, and habitual use of footwear. High speed video was used to measure lower extremity kinematics at ground contact in the sagittal plane while participants ran down 13 meter-long tracks with three variables independently controlled: speed, track stiffness, and step frequency. 72% of the habitually barefoot and 32% of the habitually shod participants used multiple strike types, with significantly higher levels of foot strike variation among individuals who ran less frequently and who used lower step frequencies. There was no effect of sex, age, height or weight on foot strike angle, but individuals were more likely to midfoot or forefoot strike when they ran on a stiff surface, had a high preferred stride frequency, were habitually barefoot, and had more experience running. It is hypothesized that strike type variation during running, including a more frequent use of forefoot and midfoot strikes, used to be greater before the introduction of cushioned shoes and paved surfaces. PMID:26154285

  15. Expert Anticipatory Skill in Striking Sports: A Review and a Model

    ERIC Educational Resources Information Center

    Muller, Sean; Abernethy, Bruce

    2012-01-01

    Expert performers in striking sports can hit objects moving at high speed with incredible precision. Exceptionally well developed anticipation skills are necessary to cope with the severe constraints on interception. In this paper, we provide a review of the empirical evidence regarding expert interception in striking sports and propose a…

  16. Picket Fencing: Amid Fewer Strikes, Some See Waning Sympathy for Educators

    ERIC Educational Resources Information Center

    Sack, Joetta L.

    2006-01-01

    Once as familiar in the back-to-school ritual as falling leaves, teacher strikes seem headed for a winter freeze. According to the nation's largest teacher's union, about 15 of the National Education Association's (NEA) 14,000 local affiliates have gone on strike since the start of this school year. In Pennsylvania--a traditional union…

  17. Recognize the Phases of a School Strike and Use This Knowledge to Avoid Trouble.

    ERIC Educational Resources Information Center

    Shapiro, Arthur; Nicaud, Robert

    1980-01-01

    Outlines the four stages of a teacher strike (individual complaints become group dissatisfaction, general dissatisfaction increases union militancy, increased militancy is expressed through job actions and a strike, and cooling off occurs) and suggests ways in which an understanding of these phases can aid a board. (Author/IRT)

  18. 29 CFR 901.5 - Agreement to refrain from strike or lockout.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 4 2014-07-01 2014-07-01 false Agreement to refrain from strike or lockout. 901.5 Section... refrain from strike or lockout. As part of its conditions for entering the dispute, the Commission may request the parties to continue the terms or conditions of employment without the occurrence of a...

  19. 48 CFR 3052.222-71 - Strikes or picketing affecting access to a DHS facility.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 3052.222-71 Strikes or picketing affecting access to a DHS facility. As prescribed in (HSAR) 48 CFR 3022.101-71(b), insert the following... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Strikes or...

  20. 29 CFR 901.5 - Agreement to refrain from strike or lockout.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Agreement to refrain from strike or lockout. 901.5 Section... refrain from strike or lockout. As part of its conditions for entering the dispute, the Commission may request the parties to continue the terms or conditions of employment without the occurrence of a...

  1. 48 CFR 3052.222-71 - Strikes or picketing affecting access to a DHS facility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 3052.222-71 Strikes or picketing affecting access to a DHS facility. As prescribed in (HSAR) 48 CFR 3022.101-71(b), insert the following... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Strikes or...

  2. 29 CFR 901.5 - Agreement to refrain from strike or lockout.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 4 2013-07-01 2013-07-01 false Agreement to refrain from strike or lockout. 901.5 Section... refrain from strike or lockout. As part of its conditions for entering the dispute, the Commission may request the parties to continue the terms or conditions of employment without the occurrence of a...

  3. 29 CFR 901.5 - Agreement to refrain from strike or lockout.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 4 2011-07-01 2011-07-01 false Agreement to refrain from strike or lockout. 901.5 Section... refrain from strike or lockout. As part of its conditions for entering the dispute, the Commission may request the parties to continue the terms or conditions of employment without the occurrence of a...

  4. 48 CFR 3052.222-71 - Strikes or picketing affecting access to a DHS facility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 3052.222-71 Strikes or picketing affecting access to a DHS facility. As prescribed in (HSAR) 48 CFR 3022.101-71(b), insert the following... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Strikes or...

  5. 48 CFR 3052.222-71 - Strikes or picketing affecting access to a DHS facility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 3052.222-71 Strikes or picketing affecting access to a DHS facility. As prescribed in (HSAR) 48 CFR 3022.101-71(b), insert the following... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Strikes or...

  6. 48 CFR 3052.222-71 - Strikes or picketing affecting access to a DHS facility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 3052.222-71 Strikes or picketing affecting access to a DHS facility. As prescribed in (HSAR) 48 CFR 3022.101-71(b), insert the following... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Strikes or...

  7. 29 CFR 901.5 - Agreement to refrain from strike or lockout.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 4 2012-07-01 2012-07-01 false Agreement to refrain from strike or lockout. 901.5 Section... refrain from strike or lockout. As part of its conditions for entering the dispute, the Commission may request the parties to continue the terms or conditions of employment without the occurrence of a...

  8. Batter's Choice: Lessons for Teaching Tactics in a Modified Striking/Fielding Game

    ERIC Educational Resources Information Center

    Sinclair, Christina

    2004-01-01

    When played in their standard form, striking/fielding games are often a favorite among elementary students; yet they allow for only limited participation, which is contradictory to quality physical education. This article presents a sequence of lessons leading to Batter's Choice, a modified striking/fielding game, designed to maximize the…

  9. Along-strike sequence stratigraphy across the Cretaceous shallow marine to coastal-plain transition, Wasatch Plateau, Utah, U.S.A.

    NASA Astrophysics Data System (ADS)

    Gani, M. Royhan; Ranson, Andrew; Cross, David B.; Hampson, Gary J.; Gani, Nahid D.; Sahoo, Hiranya

    2015-07-01

    Current sequence stratigraphic models deal with stratal packages almost exclusively along depositional-dip. A high-resolution outcrop example detailing sequence stratigraphic architecture along depositional-strike is largely lacking. This outcrop study provides a detailed sequence stratigraphic correlation along depositional-strike for a length of ~ 50 km. Moreover, this study focuses on the facies and stratigraphic relationships particularly at the very transition between coeval marine and nonmarine strata, which is relatively underdocumented. Within the Mesaverde Group of central and eastern Utah, the Upper Cretaceous shallow-marine Star Point Sandstone and paralic Blackhawk Formation are relatively well studied along depositional-dip in the Book Cliffs, but the nature of their spatio-temporal transition particularly along depositional-strike in the NNE-SSW trending Wasatch Plateau remains poorly documented. Facies-scale to stratigraphic-scale data were gathered from ten outcrop "windows" along the eastern margin of the Wasatch Plateau. The vertical and lateral transition between marine and nonmarine strata varies in complexity within the study area. In the southern part of the study area near the central Wasatch Plateau, the shallow-marine Star Point Sandstone passes stratigraphically upward into the nonmarine Blackhawk Formation in one simple transition without any intercalation of marine and nonmarine strata. In the northern part of the study area, however, where the Star Point Sandstone to Blackhawk Formation transition is complex, aggradationally stacked shallow-marine sandbodies (i.e., parasequences) taper and completely pinch-out within coastal-plain mudstones in a paleo-landward direction over short distances (< 1 km), representing potential stratigraphic traps. These marine sandbodies are intercalated with coeval nonmarine strata within the Blackhawk Formation. Fourth-order sequence boundaries and flooding surfaces were correlated along the lower

  10. Positive Functions of Emotions in Achievement Sports

    ERIC Educational Resources Information Center

    Puig, Nuria; Vilanova, Anna

    2011-01-01

    This article presents the results of two research projects on the emotions of men engaged in achievement outdoor sports. The conditions were analyzed under which emotions carry out positive functions. The question strikes us as a fundamental one, because it is of crucial importance when it comes to increasing sportspeople's success. The…

  11. Leap and strike kinetics of an acoustically 'hunting' barn owl (Tyto alba).

    PubMed

    Usherwood, James R; Sparkes, Emily L; Weller, Renate

    2014-09-01

    Barn owls are effective hunters of small rodents. One hunting technique is a leap from the ground followed by a brief flight and a plummeting 'strike' onto an acoustically targeted - and potentially entirely hidden - prey. We used forceplate measurements to derive kinetics of the leap and strike. Leaping performance was similar to reported values for guinea fowl. This is likely achieved despite the owl's considerably smaller size because of its relatively long legs and use of wing upstroke. Strikes appear deliberately forceful: impulses could have been spread over larger periods during greater deflections of the centre of mass, as observed in leaping and an alighting landing measurement. The strike, despite forces around 150 times that of a mouse body weight, is not thought to be crucial to the kill; rather, forceful strikes may function primarily to enable rapid penetration of leaf litter or snow cover, allowing grasping of hidden prey. PMID:24948629

  12. Effects of the Israel physicians' strike on the treatment and outcome of acute appendicitis in Jerusalem.

    PubMed

    Ellencweig, A Y; Ginat-Israeli, T

    1990-10-01

    We sought to determine whether a prolonged physicians' strike causes changes in the delivery of health care and in the behavior of health care seekers? We compared appendectomy patients during the 1983 physicians' strike in Israel and during a control period in 1984, by analyzing the records of 171 patients in two Jerusalem hospitals. Patients had similar demographic characteristics and disease manifestation, but differed in their health care seeking behavior. The 1983 patients tended to postpone their first contact with the health system and frequently failed to present themselves for a follow-up visit after discharge. Control group patients were more likely to receive preoperative antibiotics and less likely to develop postoperative fever than the strike group patients. The findings confirmed that the differences between the strike and control groups were caused by administrative barriers resulting from the strike rather than by differences in actual medical treatment. PMID:2249930

  13. Retrieval-Based Model Accounts for Striking Profile of Episodic Memory and Generalization.

    PubMed

    Banino, Andrea; Koster, Raphael; Hassabis, Demis; Kumaran, Dharshan

    2016-01-01

    A fundamental theoretical tension exists between the role of the hippocampus in generalizing across a set of related episodes, and in supporting memory for individual episodes. Whilst the former requires an appreciation of the commonalities across episodes, the latter emphasizes the representation of the specifics of individual experiences. We developed a novel version of the hippocampal-dependent paired associate inference (PAI) paradigm, which afforded us the unique opportunity to investigate the relationship between episodic memory and generalization in parallel. Across four experiments, we provide surprising evidence that the overlap between object pairs in the PAI paradigm results in a marked loss of episodic memory. Critically, however, we demonstrate that superior generalization ability was associated with stronger episodic memory. Through computational simulations we show that this striking profile of behavioral findings is best accounted for by a mechanism by which generalization occurs at the point of retrieval, through the recombination of related episodes on the fly. Taken together, our study offers new insights into the intricate relationship between episodic memory and generalization, and constrains theories of the mechanisms by which the hippocampus supports generalization. PMID:27510579

  14. Retrieval-Based Model Accounts for Striking Profile of Episodic Memory and Generalization

    PubMed Central

    Banino, Andrea; Koster, Raphael; Hassabis, Demis; Kumaran, Dharshan

    2016-01-01

    A fundamental theoretical tension exists between the role of the hippocampus in generalizing across a set of related episodes, and in supporting memory for individual episodes. Whilst the former requires an appreciation of the commonalities across episodes, the latter emphasizes the representation of the specifics of individual experiences. We developed a novel version of the hippocampal-dependent paired associate inference (PAI) paradigm, which afforded us the unique opportunity to investigate the relationship between episodic memory and generalization in parallel. Across four experiments, we provide surprising evidence that the overlap between object pairs in the PAI paradigm results in a marked loss of episodic memory. Critically, however, we demonstrate that superior generalization ability was associated with stronger episodic memory. Through computational simulations we show that this striking profile of behavioral findings is best accounted for by a mechanism by which generalization occurs at the point of retrieval, through the recombination of related episodes on the fly. Taken together, our study offers new insights into the intricate relationship between episodic memory and generalization, and constrains theories of the mechanisms by which the hippocampus supports generalization. PMID:27510579

  15. A sonic net excludes birds from an airfield: implications for reducing bird strike and crop losses.

    PubMed

    Swaddle, John P; Moseley, Dana L; Hinders, Mark K; Smith, Elizabeth P

    2016-03-01

    Collisions between birds and aircraft cause billions of dollars of damages annually to civil, commercial, and military aviation. Yet technology to reduce bird strike is not generally effective, especially over longer time periods. Previous information from our lab indicated that filling an area with acoustic noise, which masks important communication channels for birds, can displace European Starlings (Sturnus vulgaris) from food sources. Here we deployed a spatially controlled noise (termed a "sonic net"), designed to overlap with the frequency range of bird vocalizations, at an airfield. By conducting point counts, we monitored the presence of birds for four weeks before deployment of our sonic net, and for four weeks during deployment. We found an 82% reduction in bird presence in the sonic net area compared with change in the reference areas. This effect was as strong in the fourth week of exposure as in the first week. We also calculated the potential costs avoided resulting from this exclusion. We propose that spatially controlled acoustic manipulations that mask auditory communication for birds may be an effective long term and fairly benign way of excluding problem birds from areas of socioeconomic importance, such as airfields, agricultural sites, and commercial properties. PMID:27209777

  16. Developing personal values: trainees' attitudes toward strikes by health care providers.

    PubMed

    Li, Su-Ting T; Srinivasan, Malathi; Der-Martirosian, Claudia; Kravitz, Richard L; Wilkes, Michael S

    2011-05-01

    Worldwide, health care providers use strikes and job actions to influence policy. For health care providers, especially physicians, strikes create an ethical tension between an obligation to care for current patients (e.g., to provide care and avoid abandonment) and an obligation to better care for future patients by seeking system improvements (e.g., improvements in safety, to access, and in the composition and strength of the health care workforce). This tension is further intensified when the potential benefit of a strike involves professional self-interest and the potential risk involves patient harm or death. By definition, trainees are still forming their professional identities and values, including their opinions on fair wages, health policy, employee benefits, professionalism, and strikes. In this article, the authors explore these ethical tensions, beginning with a discussion of reactions to a potential 2005 nursing strike at the University of California, Davis, Medical Center. The authors then propose a conceptual model describing factors that may influence health care providers' decisions to strike (including personal ethics, personal agency, and strike-related context). In particular, the authors explore the relationship between training level and attitudes toward taking a job action, such as going on strike. Because trainees' attitudes toward strikes continue to evolve during training, the authors maintain that open discussion around the ethics of health care professionals' strikes and other methods of conflict resolution should be included in medical education to enhance professionalism and systems-based practice training. The authors include sample case vignettes to help initiate these important discussions. PMID:21436671

  17. Nursing Positions

    MedlinePlus

    ... Story" 5 Things to Know About Zika & Pregnancy Nursing Positions KidsHealth > For Parents > Nursing Positions Print A ... and actually needs to feed. Getting Comfortable With Breastfeeding Nursing can be one of the most challenging ...

  18. Improved determination of the position and activity of a radioactive point source inside a bulky medium using several detectors. The special case of a lung counter--a general view.

    PubMed

    Pelled, Omer; Bonardi, Mauro L; German, Uzi; Groppi, Flavia; Alfassi, Zeev B

    2007-02-01

    A method is described to locate a radioactive point source in a lung using a commercial array of lung detectors. The method takes advantage of the fact that modern commercial systems consist of several Ge detectors, each connected to a multi-channel analyzer, and the information from each detector can be analyzed separately. The system is calibrated with point sources placed in various locations in the lungs of a phantom. A vector method is presented for determining which of the calibration locations in the phantom is closest to the location of the unknown point source. It has been shown that the accuracy of the method increases with increasing number of the vector dimensions. A higher dimensionality can be achieved by analyzing counts of several gamma lines or by using more detectors. PMID:16928446

  19. Symphyotrichum ericoides populations from seleniferous and nonseleniferous soil display striking variation in selenium accumulation.

    PubMed

    El Mehdawi, Ali F; Paschke, Mark W; Pilon-Smits, Elizabeth A H

    2015-04-01

    Symphyotrichum ericoides (Asteraceae) from naturally seleniferous habitat (Pine Ridge) was shown previously to have selenium (Se) hyperaccumulator properties in field and glasshouse studies, and to benefit from Se through protection from herbivory. To investigate whether Se hyperaccumulation is ubiquitous in S. ericoides or restricted to seleniferous soils, the S. ericoides Pine Ridge (PR) population was compared with the nearby Cloudy Pass (CP) population from nonseleniferous soil. The S. ericoidesPR and CP populations were strikingly physiologically different: in a common garden experiment, PR plants accumulated up to 40-fold higher Se concentrations than CP plants and had 10-fold higher Se : sulfur (S) ratios. Moreover, roots of S. ericoidesPR plants showed directional growth toward selenate, while CP roots did not. Growth of both accessions responded positively to Se. Each accession grew best on its own soil. Rhizosphere soil inoculum from the S. ericoidesPR population stimulated plant growth and Se accumulation in both S. ericoidesPR and S. ericoidesCP plants, on both PR and CP soils. While the S. ericoidesPR population hyperaccumulates Se, the nearby CP population does not. The capacity of S. ericoidesPR plants to hyperaccumulate Se appears to be a local phenomenon that is restricted to seleniferous soil. Mutualistic rhizosphere microbes of the S. ericoidesPR population may contribute to the hyperaccumulation phenotype. PMID:25406635

  20. Striking Discrepancy of Anomalous Body Experiences with Normal Interoceptive Accuracy in Depersonalization-Derealization Disorder

    PubMed Central

    Michal, Matthias; Reuchlein, Bettina; Adler, Julia; Reiner, Iris; Beutel, Manfred E.; Vögele, Claus; Schächinger, Hartmut; Schulz, André

    2014-01-01

    Background Disembodiment is a core feature of depersonalization disorder (DPD). Given the narratives of DPD patients about their disembodiment and emotional numbing and neurobiological findings of an inhibition of insular activity, DPD may be considered as a mental disorder with specific impairments of interoceptive awareness and body perception. Methods We investigated cardioceptive accuracy (CA) of DPD patients (n = 24) as compared to healthy controls (n = 26) with two different heartbeat detection tasks (“Schandry heartbeat counting task” and “Whitehead heartbeat discrimination task”). Self-rated clearness of body perception was measured by questionnaire. Results Contrary to our hypothesis, DPD patients performed similarly to healthy controls on the two different heartbeat detection tasks, and they had equal scores regarding their self-rated clearness of body perception. There was no correlation of the severity of “anomalous body experiences” and depersonalization with measures of interoceptive accuracy. Only among healthy controls CA in the Schandry task was positively correlated with self-rated clearness of body perception. Depersonalization was unrelated to severity of depression or anxiety, while depression and anxiety were highly correlated. Anxiety and depression did not modify the associations of depersonalization with interoceptive accuracy. Conclusions Our main findings highlight a striking discrepancy of normal interoception with overwhelming experiences of disembodiment in DPD. This may reflect difficulties of DPD patients to integrate their visceral and bodily perceptions into a sense of their selves. This problem may be considered an important target for psychotherapeutic treatment approaches. PMID:24587061