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Sample records for non-circular streaming motions

  1. EFFECTS OF NON-CIRCULAR MOTIONS ON AZIMUTHAL COLOR GRADIENTS

    SciTech Connect

    Martinez-Garcia, Eric E.; Gonzalez-Lopezlira, Rosa A.; Gomez, Gilberto C. E-mail: r.gonzalez@crya.unam.m

    2009-12-20

    Assuming that density waves trigger star formation, and that young stars preserve the velocity components of the molecular gas where they are born, we analyze the effects that non-circular gas orbits have on color gradients across spiral arms. We try two approaches, one involving semianalytical solutions for spiral shocks, and another with magnetohydrodynamic (MHD) numerical simulation data. We find that, if non-circular motions are ignored, the comparison between observed color gradients and stellar population synthesis models would in principle yield pattern speed values that are systematically too high for regions inside corotation, with the difference between the real and the measured pattern speeds increasing with decreasing radius. On the other hand, image processing and pixel averaging result in systematically lower measured spiral pattern speed values, regardless of the kinematics of stellar orbits. The net effect is that roughly the correct pattern speeds are recovered, although the trend of higher measured OMEGA{sub p} at lower radii (as expected when non-circular motions exist but are neglected) should still be observed. We examine the MartInez-GarcIa et al. photometric data and confirm that this is indeed the case. The comparison of the size of the systematic pattern speed offset in the data with the predictions of the semianalytical and MHD models corroborates that spirals are more likely to end at outer Lindblad resonance, as these authors had already found.

  2. Analyzing Non-circular Motions in Spiral Galaxies Through 3D Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fuentes-Carrera, I.; Rosado, M.; Amram, P.

    3D spectroscopic techniques allow the assessment of different types of motions in extended objects. In the case of spiral galaxies, thes type of techniques allow us to trace not only the (almost) circular motion of the ionized gas, but also the motions arising from the presence of structure such as bars, spiral arms and tidal features. We present an analysis of non-circular motions in spiral galaxies in interacting pairs using scanning Fabry-Perot interferometry of emission lines. We show how this analysis can be helpful to differentiate circular from non-circular motions in the kinematical analysis of this type of galaxies.

  3. The power spectra of non-circular motions in disk galaxies

    NASA Astrophysics Data System (ADS)

    Westfall, Kyle; Laws, Anna S. E.; MaNGA Team

    2016-01-01

    Using data from the first year of the SDSS-IV/MaNGA survey, we present a preliminary study of the amplitude of non-circular motions in a sample of disk galaxies. We select galaxies that have either a visual classification as a spiral galaxy by the Galaxy Zoo project (Lintott et al. 2011) and/or a measured Sersic index of less than 2.5 from the NASA-Sloan Atlas (nsatlas.org). We also remove high-inclination systems by selecting galaxies with isophotal ellipticity measurements of less than 0.6, implying an inclination of less than 65 degrees. For each galaxy, we fit a tilted-disk model to the observed line-of-sight velocities (Andersen & Bershady 2013). The geometric projection of the circularly rotating disk is simultaneously fit to both the ionized-gas (H-alpha) and stellar kinematics, whereas the rotation curves of the two dynamical tracers are allowed to be independent. We deproject the residuals of the velocity-field fit to the disk-plane polar coordinates and select a radial region that is fully covered in aziumuth, yet not undersampled by the on-sky spaxel. Similar to the approach taken by Bovy et al. (2015) for the Milky Way, we then compute the two-dimensional power spectrum of this velocity-residual map, which provides the amplitude of non-circular motions at all modes probed by the data. Our preliminary analysis reveals disk-plane non-circular motions in both the stars and ionized-gas with typical peak amplitudes of approximately 20 km/s. Additionally, our initial findings appear to demonstrate that non-circular motions in barred galaxies are stronger in the ionized gas than in the stars, a trend not seen in unbarred galaxies.

  4. Non-circular motion estimation of the grand-design spiral galaxy NGC 628

    NASA Astrophysics Data System (ADS)

    Colombo, D.

    2013-09-01

    I present a harmonic decomposition analysis of the grand-design spiral galaxy NGC 628 using the H I data from The H I Nearby Galaxy Survey (THINGS), Walter et al., Astron. J. 136, 2563 (2008). The harmonic decomposition analysis allows the estimation of the peculiar motion magnitude of the galaxy not counted in the rotation of the disk. The rotation curve is obtained through a tilted ring analysis and reaches a maximum velocity not higher than 200 km s-1. The residual from the velocity field shows a morphology shift from a m = 1 to a m = 3 feature at R = 120", typical of two spiral arms perturbation of the potential. The non-circular motion have a magnitude of ~10 km s-1, in agreement with previous studies of similar Hubble type galaxies.

  5. Exploring the GalMer database: bar properties and non-circular motions

    NASA Astrophysics Data System (ADS)

    Randriamampandry, T. H.; Deg, N.; Carignan, C.; Combes, F.; Spekkens, K.

    2016-10-01

    Context. We use Tree-SPH simulations from the GalMer database to characterize and quantify the non-circular motions induced by the presence of bar-like structures on the observed rotation curve of barred galaxies derived from empirical models of their line-of-sight velocity maps. The GalMer database consists of SPH simulations of galaxies spanning a wide range of morphological types and sizes. Aims: The aim is to compare the intrinsic velocities and bar properties from the simulations with those derived from pseudo-observations. This allows us to estimate the amount of non-circularity and to test the various methods used to derive the bar properties and rotation curves. Methods: The intrinsic velocities in the simulations are calculated from the gravitational forces whereas the observed rotation velocities are derived by applying the ROTCUR and DiskFit algorithms to well-resolved observations of intermediate-inclination, strongly barred galaxies. Results: Our results confirm that the tilted ring method implemented in ROTCUR systematically underestimates or overestimates the rotational velocities by up to 40 percent in the inner part of the galaxy when the bar is aligned with one of the symmetry axes for all the models. For the DiskFit analysis, we find that it produces unrealistic values for all the models used in this work when the bar is within approximately ten degrees of the major or minor axis.

  6. Stochastic non-circular motion and outflows driven by magnetic activity in the Galactic bulge region

    NASA Astrophysics Data System (ADS)

    Suzuki, Takeru K.; Fukui, Yasuo; Torii, Kazufumi; Machida, Mami; Matsumoto, Ryoji

    2015-12-01

    By performing a global magnetohydrodynamical simulation for the Milky Way with an axisymmetric gravitational potential, we propose that spatially dependent amplification of magnetic fields possibly explains the observed noncircular motion of the gas in the Galactic centre region. The radial distribution of the rotation frequency in the bulge region is not monotonic in general. The amplification of the magnetic field is enhanced in regions with stronger differential rotation, because magnetorotational instability and field-line stretching are more effective. The strength of the amplified magnetic field reaches ≳0.5 mG, and radial flows of the gas are excited by the inhomogeneous transport of angular momentum through turbulent magnetic field that is amplified in a spatially dependent manner. In addition, the magnetic pressure-gradient force also drives radial flows in a similar manner. As a result, the simulated position-velocity diagram exhibits a time-dependent asymmetric parallelogram-shape owing to the intermittency of the magnetic turbulence; the present model provides a viable alternative to the bar-potential-driven model for the parallelogram shape of the central molecular zone. This is a natural extension into the central few 100 pc of the magnetic activity, which is observed as molecular loops at radii from a few 100 pc to 1 kpc. Furthermore, the time-averaged net gas flow is directed outward, whereas the flows are highly time dependent, which we discuss from a viewpoint of the outflow from the bulge.

  7. Shock structure in non-circular jets

    NASA Technical Reports Server (NTRS)

    Morris, Philip J.; Bhat, Thonse R. S.

    1989-01-01

    The shock-cell structure of supersonic jets with non-circular exit geometry is modeled using a linearized analysis. The model takes into account the finite thickness of the jet shear layer using realistic velocity and density profiles. The effects of the shear layer turbulence are included by incorporating eddy-viscosity terms. A finite-difference numerical method is used to solve the steady linearized equations of motion. A body-fitted coordinate system is used to describe the shear layer. The variation of the pressure fluctuation with downstream distance is given for circular jets and for an elliptic jet of aspect ratio 2.0. Comparisons with experimental data are made. Difficulties with the numerical technique are also discussed.

  8. Gas streaming motions towards the nucleus of M81

    NASA Astrophysics Data System (ADS)

    Schnorr Müller, Allan; Storchi-Bergmann, Thaisa; Riffel, Rogemar A.; Ferrari, Fabricio; Steiner, J. E.; Axon, David J.; Robinson, Andrew

    2011-05-01

    We present two-dimensional stellar and gaseous kinematics of the inner 120 × 250 pc2 of the LINER/Seyfert 1 galaxy M81, from optical spectra obtained with the Gemini Multi-Object Spectrograph (GMOS) integral field spectrograph on the Gemini-North telescope at a spatial resolution of ≈10 pc. The stellar velocity field shows circular rotation and, overall, is very similar to the published large-scale velocity field, but deviations are observed close to the minor axis which can be attributed to stellar motions possibly associated with a nuclear bar. The stellar velocity dispersion of the bulge is 162 ± 15 km s-1, in good agreement with previous measurements and leading to a black hole mass of MBH= 5.5+3.6-2.0× 107 M⊙ based on the MBH-σ relationship. The gas kinematics is dominated by non-circular motions and the subtraction of the stellar velocity field reveals blueshifts of ≈-100 km s-1 on the far side of the galaxy and a few redshifts on the near side. These characteristics can be interpreted in terms of streaming towards the centre if the gas is in the plane. On the basis of the observed velocities and geometry of the flow, we estimate a mass inflow rate in ionized gas of ≈4.0 × 10-3 M⊙ yr-1, which is of the order of the accretion rate necessary to power the LINER nucleus of M81. We have also applied the technique of principal component analysis (PCA) to our data, which reveals the presence of a rotating nuclear gas disc within ≈50 pc from the nucleus and a compact outflow, approximately perpendicular to the disc. The PCA combined with the observed gas velocity field shows that the nuclear disc is being fed by gas circulating in the galaxy plane. The presence of the outflow is supported by a compact jet seen in radio observations at a similar orientation, as well as by an enhancement of the [O I]/Hα line ratio, probably resulting from shock excitation of the circumnuclear gas by the radio jet. With these observations we are thus resolving both the

  9. Rotatable non-circular forebody flow controller

    NASA Technical Reports Server (NTRS)

    Moskovitz, Cary A. (Inventor)

    1991-01-01

    The invention is a rotatable, non-circular forebody flow controller. The apparatus comprises a small geometric device located at a nose of a forebody of an aircraft and a non-circular cross-sectional area that extends toward the apex of the aircraft. The device is symmetrical about a reference plane and preferably attaches to an axle which in turn attaches to a rotating motor. The motor rotates the device about an axis of rotation. Preferably, a control unit connected to an aircraft flight control computer signals to the rotating motor the proper rotational positioning of the geometric device.

  10. Combustor with non-circular head end

    DOEpatents

    Kim, Won -Wook; McMahan, Kevin Weston

    2015-09-29

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a head end with a non-circular configuration, a number of fuel nozzles positioned about the head end, and a transition piece extending downstream of the head end.

  11. Rectified Motion of Microparticles: Generalizing Streaming and Radiation Forces

    NASA Astrophysics Data System (ADS)

    Raju, David; Agarwal, Siddhansh; Rallabandi, Bhargav; Hilgenfeldt, Sascha

    2016-11-01

    It is well known that a wide variety of oscillating flows gives rise to steady streaming, i.e., rectified motion of fluid elements. Small spherical particles introduced into such a flow have been shown to experience an additional lift force that ultimately leads to particle trajectories that differ systematically from the fluid element pathlines. We demonstrate a systematic derivation of this differential particle motion on the steady streaming time scale, so that time-averaged particle trajectories can be directly predicted without computation on the fast, oscillatory time scale. The resulting dynamics can be interpreted as a generalization of streaming flow, while the closed-form lift force provides a generalization of the secondary radiation force, to which it reduces in appropriate limiting cases. These very general results are validated by comparison with experiments in the context of bubble streaming, but apply to a large class of other flows as well.

  12. Shape and motion from image streams: a factorization method.

    PubMed Central

    Tomasi, C; Kanade, T

    1993-01-01

    Inferring scene geometry and camera motion from a stream of images is possible in principle, but it is an ill-conditioned problem when the objects are distant with respect to their size. We have developed a factorization method that can overcome this difficulty by recovering shape and motion without computing depth as an intermediate step. An image stream can be represented by the 2F x P measurement matrix of the image coordinates of P points tracked through F frames. Under orthographic projection this matrix is of rank 3. Using this observation, the factorization method uses the singular value decomposition technique to factor the measurement matrix into two matrices, which represent object shape and camera motion, respectively. The method can also handle and obtain a full solution from a partially filled-in measurement matrix, which occurs when features appear and disappear in the image sequence due to occlusions or tracking failures. The method gives accurate results and does not introduce smoothing in either shape or motion. We demonstrate this with a series of experiments on laboratory and outdoor image streams, with and without occlusions. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 11 Fig. 12 PMID:11607434

  13. Failure of Non-Circular Composite Cylinders

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.

    2004-01-01

    In this study, a progressive failure analysis is used to investigate leakage in internally pressurized non-circular composite cylinders. This type of approach accounts for the localized loss of stiffness when material failure occurs at some location in a structure by degrading the local material elastic properties by a certain factor. The manner in which this degradation of material properties takes place depends on the failure modes, which are determined by the application of a failure criterion. The finite-element code STAGS, which has the capability to perform progressive failure analysis using different degradation schemes and failure criteria, is utilized to analyze laboratory scale, graphite-epoxy, elliptical cylinders with quasi-isotropic, circumferentially-stiff, and axially-stiff material orthotropies. The results are divided into two parts. The first part shows that leakage, which is assumed to develop if there is material failure in every layer at some axial and circumferential location within the cylinder, does not occur without failure of fibers. Moreover before fibers begin to fail, only matrix tensile failures, or matrix cracking, takes place, and at least one layer in all three cylinders studied remain uncracked, preventing the formation of a leakage path. That determination is corroborated by the use of different degradation schemes and various failure criteria. Among the degradation schemes investigated are the degradation of different engineering properties, the use of various degradation factors, the recursive or non-recursive degradation of the engineering properties, and the degradation of material properties using different computational approaches. The failure criteria used in the analysis include the noninteractive maximum stress criterion and the interactive Hashin and Tsai-Wu criteria. The second part of the results shows that leakage occurs due to a combination of matrix tensile and compressive, fiber tensile and compressive, and inplane

  14. Hubble Space Telescope Proper Motions of Individual Stars in Stellar Streams: Orphan, Sagittarius, Lethe, and the New "Parallel’ Stream"

    NASA Astrophysics Data System (ADS)

    Sohn, Sangmo Tony; van der Marel, Roeland P.; Kallivayalil, Nitya; Majewski, Steven R.; Besla, Gurtina; Carlin, Jeffrey L.; Law, David R.; Siegel, Michael H.; Anderson, Jay

    2016-12-01

    We present a multi-epoch Hubble Space Telescope (HST) study of stellar proper motions (PMs) for four fields along the Orphan Stream. We determine absolute PMs of several individual stars per target field using established techniques that utilize distant background galaxies to define a stationary reference frame. Five Orphan Stream stars are identified in one of the four fields based on combined color-magnitude and PM information. The average PM is consistent with the existing model of the Orphan Stream by Newberg et al. In addition to the Orphan Stream stars, we detect stars that likely belong to other stellar streams. To identify which stellar streams these stars belong to, we examine the 2d bulk motion of each group of stars on the sky by subtracting the PM contribution of the solar motion (which is a function of position on the sky and distance) from the observed PMs, and comparing the vector of net motion with the spatial extent of known stellar streams. By doing this, we identify candidate stars in the Sagittarius and Lethe streams, and a newly found stellar stream at a distance of ˜17 kpc, which we tentatively name the “Parallel Stream.” Together with our Sagittarius stream study, this work demonstrates that even in the Gaia era, HST will continue to be advantageous in measuring PMs of old stellar populations on a star-by-star basis, especially for distances beyond ˜10 kpc.

  15. Airfoil in sinusoidal motion in a pulsating stream

    NASA Technical Reports Server (NTRS)

    Greenberg, J Mayo

    1947-01-01

    The forces and moments on a two-dimensional airfoil executing harmonic motions in a pulsating stream are derived on the basis of non-stationary incompressible potential flow theory, with the inclusion of the effect of the continuous sheet of vortices shed from the trailing edge. An assumption as to the form of the wake is made with a certain degree of approximation. A comparison with previous work applicable only to the special case of a stationary airfoil is made by means of a numerical example, and the excellent agreement obtained shows that the wake approximation is quite sufficient. The results obtained are expected to be useful in considerations of forced vibrations and flutter of rotary wing aircraft.

  16. Drops with non-circular footprints

    NASA Astrophysics Data System (ADS)

    Ravazzoli, Pablo D.; González, Alejandro G.; Diez, Javier A.

    2016-04-01

    In this paper we study the morphology of drops formed on partially wetting substrates, whose footprint is not circular. These drops are consequence of the breakup processes occurring in thin films when anisotropic contact line motions take place. The anisotropy is basically due to the hysteresis of the contact angle since there is a wetting process in some parts of the contact line, while a dewetting occurs in other parts. Here, we obtain a characteristic drop shape from the rupture of a long liquid filament sitting on a solid substrate. We analyze its shape and contact angles by means of goniometric and refractive techniques. We also find a non-trivial steady state solution for the drop shape within the long wave approximation (lubrication theory), and we compare most of its features with experimental data. This solution is presented both in Cartesian and polar coordinates, whose constants must be determined by a certain group of measured parameters. Besides, we obtain the dynamics of the drop generation from numerical simulations of the full Navier-Stokes equation, where we emulate the hysteretic effects with an appropriate spatial distribution of the static contact angle over the substrate.

  17. Development of laser finishing for non-circular profiles

    SciTech Connect

    Liu, K.W.; Sheng, P.S.

    1995-03-01

    A laser-based technique for finishing of non-circular cylindrical parts is presented. In this process, the frequency characteristics of a desired non-circular shape is extracted from a CAD through a Fast Fourier Transform algorithm and implemented through a CO{sub 2} laser machining system. A galvanometer-based scanner is used in the process to achieve programmable beam trajectories and high-speed finishing. An error estimation scheme can be developed to determine the final dimensional error of the non-circular profile. This process can be selected as both a batch production tool and a rapid prototyping tool based on the designated processing rate and precision. Initial experimental results include the production of two- and three-lobed profiles, as well as definition of part feature using higher-order harmonics, in polymethylmethacrylate (PMMA) with corresponding R{sub a} values of less than 1 {mu}m. The machine tool elements and general procedure for non-circular laser finishing are also presented.

  18. Fishing in Tidal Streams: New Radial Velocity and Proper Motion Constraints on the Orbit of the Anticenter Stream

    NASA Astrophysics Data System (ADS)

    Grillmair, C. J.; Carlin, Jeffrey L.; Majewski, Steven R.

    2008-12-01

    We have obtained radial velocity measurements for stars in two widely separated fields in the Anticenter Stream. Combined with SDSS/USNO-B proper motions, the new measurements allow us to establish that the stream is on a nearly circular, somewhat inclined, prograde orbit around the Galaxy. While the orbital eccentricity is similar to that previously determined for the Monoceros stream, the sizes, inclinations, and positions of the orbits for the two systems differ significantly. Integrating our best-fitting Anticenter Stream orbit forward, we find that it is closely aligned along and lies almost on top of a streamlike feature previously designated the "Eastern Banded Structure." The position of this feature coincides with the apogalacticon of the orbit. We tentatively conclude that this feature is the next wrap of the Anticenter Stream.

  19. Two-dimensional single-stream electron motion in a coaxial diode with magnetic insulation

    SciTech Connect

    Fuks, Mikhail I.; Schamiloglu, Edl

    2014-05-15

    One of the most widespread models of electrons drifting around the cathode in magnetrons is the single-stream state, which is the Brillouin stream with purely azimuthal motion. We describe a single-stream state in which electrons not only move in the azimuthal direction, but also along the axial direction, which is useful for consideration, for example, of relativistic magnetrons, MILOs, and coaxial transmission lines. Relations are given for the conditions of magnetic insulation for 2D electron motion, for 1D azimuthal and axial motion, and for synchronism of these streams with the operating waves of M-type microwave sources. Relations are also provided for the threshold of generation in magnetrons with 2D electron motion.

  20. Structural Concepts Study of Non-circular Fuselage Configurations

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, Vivel

    1996-01-01

    A preliminary study of structural concepts for noncircular fuselage configurations is presented. For an unconventional flying-wing type aircraft, in which the fuselage is inside the wing, multiple fuselage bays with non-circular sections need to be considered. In a conventional circular fuselage section, internal pressure is carried efficiently by a thin skin via hoop tension. If the section is non-circular, internal pressure loads also induce large bending stresses. The structure must also withstand additional bending and compression loads from aerodynamic and gravitational forces. Flat and vaulted shell structural configurations for such an unconventional, non-circular pressurized fuselage of a large flying-wing were studied. A deep honeycomb sandwich-shell and a ribbed double-wall shell construction were considered. Combinations of these structural concepts were analyzed using both analytical and simple finite element models of isolated sections for a comparative conceptual study. Weight, stress, and deflection results were compared to identify a suitable configuration for detailed analyses. The flat sandwich-shell concept was found preferable to the vaulted shell concept due to its superior buckling stiffness. Vaulted double-skin ribbed shell configurations were found to be superior due to their weight savings, load diffusion, and fail-safe features. The vaulted double-skin ribbed shell structure concept was also analyzed for an integrated wing-fuselage finite element model. Additional problem areas such as wing-fuselage junction and pressure-bearing spar were identified.

  1. Three-dimensional interplanetary stream magnetism and energetic particle motion

    NASA Technical Reports Server (NTRS)

    Barouch, E.; Burlaga, L. F.

    1976-01-01

    Cosmic rays interact with mesoscale configurations of the interplanetary magnetic field. A technique is presented for calculating such configurations in the inner solar system, which are due to streams and source conditions near the sun, and maps of magnetic field are constructed for some plausible stream and source conditions. One effect of these mesoscale configurations on galactic cosmic rays is shown to be an out-of-the-ecliptic gradient drift sufficient to explain Forbush decreases. The effects on solar energetic particles include small polar drifts due to the field gradients and a possibly large modification of the time-intensity profiles and anisotropy characteristics due to the formation of mirror configurations in space. If a diffusion model is applicable to solar particles, the true diffusion coefficient will be masked by the effects of streams. A conceptual model which incorporates these ideas and those of several other models is presented.

  2. AN ASYMMETRIC STREAMING MOTION IN THE GALACTIC BULGE X-SHAPED STRUCTURE REVEALED BY OGLE-III PROPER MOTIONS

    SciTech Connect

    Poleski, Radosław; Gould, Andrew; Udalski, Andrzej; Szymański, M. K.; Soszyński, I.; Kubiak, M.; Pietrzyński, G.; Ulaczyk, K.; Wyrzykowski, Ł.

    2013-10-20

    The Galactic bulge shows a double red clump in sightlines at |b| ∼> 5° and –3° ∼< l ∼< 4°. This dump is interpreted as the signature of an X-shaped structure seen almost edge-on. We measure the proper motions of the stars belonging to the closer and the further arms of the X-shaped structure. The intrinsic kinematic properties of the two arms are found by incorporating information taken from the luminosity function. At b = –5°, we find that the proper motion difference between the two arms is a linear function of Galactic longitude for –0.°1 < l < 0.°5, which we interpret as a streaming motion of the stars within the X-shaped structure. A streaming motion was previously reported based on radial velocity data, not the proper motions. The proper motion difference in longitude is constant for –0.°8 < l < –0.°1, which provides an estimate of the bulge rotational speed of 87.9 ± 8.2 km s{sup –1} kpc{sup –1}.

  3. Adaptation disrupts motion integration in the primate dorsal stream

    PubMed Central

    Patterson, Carlyn A.; Wissig, Stephanie C.; Kohn, Adam

    2014-01-01

    Summary Sensory systems adjust continuously to the environment. The effects of recent sensory experience—or adaptation—are typically assayed by recording in a relevant subcortical or cortical network. However, adaptation effects cannot be localized to a single, local network. Adjustments in one circuit or area will alter the input provided to others, with unclear consequences for computations implemented in the downstream circuit. Here we show that prolonged adaptation with drifting gratings, which alters responses in the early visual system, impedes the ability of area MT neurons to integrate motion signals in plaid stimuli. Perceptual experiments reveal a corresponding loss of plaid coherence. A simple computational model shows how the altered representation of motion signals in early cortex can derail integration in MT. Our results suggest that the effects of adaptation cascade through the visual system, derailing the downstream representation of distinct stimulus attributes. PMID:24507198

  4. Stream restoration monitoring using Structure-from-Motion photogrammetry, Teton Creek, Idaho

    NASA Astrophysics Data System (ADS)

    Stegman, Tobin K.

    Stream restoration is a rapidly growing field in applied fluvial geomorphology. Monitoring provides an essential tool for tracking restoration project success, and can improve a project's effectiveness, but often is neglected due to budgetary limitations. This research investigates the potential of Structure-from-Motion photogrammetry to provide an inexpensive and accurate method for monitoring river restoration projects. Structure-from-Motion field survey data was collected in the summer of 2014 to evaluate the performance of a recent stream restoration project intended to reduce erosion along a 1.9 km reach of Teton Creek in eastern Idaho. Channel changes were quantified by creating a digital elevation model of difference that compared an initial, as-built Global Positioning System survey to Structure-from-Motion photogrammetry data collected one year after project completion. A morphological sediment budget and a two-dimensional flow model were used to investigate sediment transport within the study reach. We also used high resolution data derived from Structure-from-Motion point clouds to create continuous grain size maps for Teton Creek that in turn were used to estimate critical shear stresses for sediment entrainment. Our findings suggest Structure-from-Motion techniques provide valuable tools for river managers seeking to monitor restoration efforts. For example, we employed terrain products derived via Structure-from-Motion to verify that hardened riffle treatments effectively prevented erosion. Similarly, we demonstrated the utility of Structure-from-Motion for evaluating the sediment mass balance within the project area. This research establishes a framework for conducting Structure-from-Motion surveys of streams for use in restoration design and monitoring.

  5. Minimal cosmic background fluctuations implied by streaming motions

    NASA Technical Reports Server (NTRS)

    Juszkiewicz, Roman; Gorski, Krzysztof; Silk, Joseph

    1987-01-01

    The minimal cosmic background radiation (CBR) anisotropy implied by the presence of peculiar motions of a given amplitude on some specified scale is calculated using a new, power spectrum-independent approach. If the tentative evidence for deviations from the Hubble flow of magnitude delta V/V roughly 0.1 at V roughly 5000 km/s is confirmed, microwave background fluctuations with a coherence scale of about 2 deg and dispersion delta T/T greater than 10 to the -5th are predicted. It is found that the existing upper limits on delta T/T are not inconsistent with v(r) = 500 km/s at r = 50/h Mpc. A reduction of the observational limits on the CBR anisotropy below the authors' minimal predictions for delta T/T would challenge the current interpretation of measurements of deviations from the Hubble flow. Gravitational instability without reheating as a mechanism for generation of the large-scale structure of the universe would be in severe difficulty.

  6. Spiral structure of M51: Streaming motions across the spiral arms

    NASA Technical Reports Server (NTRS)

    Tilanus, R. P. J.; Allen, R. J.

    1990-01-01

    The atomic hydrogen (HI) and the H alpha emission line in the grand-design spiral galaxy M51 have been observed with the Westerbork Synthesis Radio Telescope and the Taurus Fabry-Perot imaging spectrometer, respectively. Across the inner spiral arms significant tangential and radial velocity gradients are detected in the H alpha emission after subtraction of the axi-symmetric component of the velocity field. The shift is positive on the inside and negative on the outside of the northern arm. Across the southern arm this situation is reversed. The direction of the shifts is such that the material is moving inward and faster compared to circular rotation in both arms, consistent with the velocity perturbations predicted by spiral density wave models for gas downstream of a spiral shock. The observed shifts amount to 20 to 30 km (s-1), corresponding to streaming motions of 60 to 90 km (s-1) in the plane of the disk (inclination angle 20 degrees). Comparable velocity gradients have also been observed by Vogel et al. in the CO emission from the inner northern arm of M51. The streaming motions in M51 are about 2 to 3 times as large as the ones found in HI by Rots in M81, and successfully modelled by Visser with a self-consistent density wave model. Researchers have not been able to detect conclusively streaming motions in the HI emission from the arms, perhaps due to the relatively poor angular resolution (approx. 15 seconds) of the HI observations.

  7. Ice stream motion facilitated by a shallow-deforming and accreting bed

    NASA Astrophysics Data System (ADS)

    Spagnolo, Matteo; Phillips, Emrys; Piotrowski, Jan A.; Rea, Brice R.; Clark, Chris D.; Stokes, Chris R.; Carr, Simon J.; Ely, Jeremy C.; Ribolini, Adriano; Wysota, Wojciech; Szuman, Izabela

    2016-02-01

    Ice streams drain large portions of ice sheets and play a fundamental role in governing their response to atmospheric and oceanic forcing, with implications for sea-level change. The mechanisms that generate ice stream flow remain elusive. Basal sliding and/or bed deformation have been hypothesized, but ice stream beds are largely inaccessible. Here we present a comprehensive, multi-scale study of the internal structure of mega-scale glacial lineations (MSGLs) formed at the bed of a palaeo ice stream. Analyses were undertaken at macro- and microscales, using multiple techniques including X-ray tomography, thin sections and ground penetrating radar (GPR) acquisitions. Results reveal homogeneity in stratigraphy, kinematics, granulometry and petrography. The consistency of the physical and geological properties demonstrates a continuously accreting, shallow-deforming, bed and invariant basal conditions. This implies that ice stream basal motion on soft sediment beds during MSGL formation is accommodated by plastic deformation, facilitated by continuous sediment supply and an inefficient drainage system.

  8. Ice stream motion facilitated by a shallow-deforming and accreting bed

    PubMed Central

    Spagnolo, Matteo; Phillips, Emrys; Piotrowski, Jan A.; Rea, Brice R.; Clark, Chris D.; Stokes, Chris R.; Carr, Simon J.; Ely, Jeremy C.; Ribolini, Adriano; Wysota, Wojciech; Szuman, Izabela

    2016-01-01

    Ice streams drain large portions of ice sheets and play a fundamental role in governing their response to atmospheric and oceanic forcing, with implications for sea-level change. The mechanisms that generate ice stream flow remain elusive. Basal sliding and/or bed deformation have been hypothesized, but ice stream beds are largely inaccessible. Here we present a comprehensive, multi-scale study of the internal structure of mega-scale glacial lineations (MSGLs) formed at the bed of a palaeo ice stream. Analyses were undertaken at macro- and microscales, using multiple techniques including X-ray tomography, thin sections and ground penetrating radar (GPR) acquisitions. Results reveal homogeneity in stratigraphy, kinematics, granulometry and petrography. The consistency of the physical and geological properties demonstrates a continuously accreting, shallow-deforming, bed and invariant basal conditions. This implies that ice stream basal motion on soft sediment beds during MSGL formation is accommodated by plastic deformation, facilitated by continuous sediment supply and an inefficient drainage system. PMID:26898399

  9. Spatially resolved streaming potentials of human intervertebral disk motion segments under dynamic axial compression.

    PubMed

    Iatridis, James C; Furukawa, Masaru; Stokes, Ian A F; Gardner-Morse, Mack G; Laible, Jeffrey P

    2009-03-01

    Intervertebral disk degeneration results in alterations in the mechanical, chemical, and electrical properties of the disk tissue. The purpose of this study is to record spatially resolved streaming potential measurements across intervertebral disks exposed to cyclic compressive loading. We hypothesize that the streaming potential profile across the disk will vary with radial position and frequency and is proportional to applied load amplitude, according to the presumed fluid-solid relative velocity and measured glycosaminoglycan content. Needle electrodes were fabricated using a linear array of AgAgCl micro-electrodes and inserted into human motion segments in the midline from anterior to posterior. They were connected to an amplifier to measure electrode potentials relative to the saline bath ground. Motion segments were loaded in axial compression under a preload of 500 N, sinusoidal amplitudes of +/-200 N and +/-400 N, and frequencies of 0.01 Hz, 0.1 Hz, and 1 Hz. Streaming potential data were normalized by applied force amplitude, and also compared with paired experimental measurements of glycosaminoglycans in each disk. Normalized streaming potentials varied significantly with sagittal position and there was a significant location difference at the different frequencies. Normalized streaming potential was largest in the central nucleus region at frequencies of 0.1 Hz and 1.0 Hz with values of approximately 3.5 microVN. Under 0.01 Hz loading, normalized streaming potential was largest in the outer annulus regions with a maximum value of 3.0 microVN. Correlations between streaming potential and glycosaminoglycan content were significant, with R(2) ranging from 0.5 to 0.8. Phasic relationships between applied force and electrical potential did not differ significantly by disk region or frequency, although the largest phase angles were observed at the outermost electrodes. Normalized streaming potentials were associated with glycosaminoglycan content, fluid, and

  10. Perceptual synchrony of audiovisual streams for natural and artificial motion sequences.

    PubMed

    Arrighi, Roberto; Alais, David; Burr, David

    2006-03-16

    We investigated the conditions necessary for perceptual simultaneity of visual and auditory stimuli under natural conditions: video sequences of conga drumming at various rhythms. Under most conditions, the auditory stream needs to be delayed for sight and sound to be perceived simultaneously. The size of delay for maximum perceived simultaneity varied inversely with drumming tempo, from about 100 ms at 1 Hz to 30 ms at 4 Hz. Random drumming motion produced similar results, with higher random tempos requiring less delay. Video sequences of disk stimuli moving along a motion profile matched to the drummer produced near-identical results. When the disks oscillated at constant speed rather than following "biological" speed variations, the delays necessary for perceptual synchrony were systematically less. The results are discussed in terms of real-world constraints for perceptual synchrony and possible neural mechanisms.

  11. Stream/bounce event perception reveals a temporal limit of motion correspondence based on surface feature over space and time.

    PubMed

    Kawachi, Yousuke; Kawabe, Takahiro; Gyoba, Jiro

    2011-01-01

    We examined how stream/bounce event perception is affected by motion correspondence based on the surface features of moving objects passing behind an occlusion. In the stream/bounce display two identical objects moving across each other in a two-dimensional display can be perceived as either streaming through or bouncing off each other at coincidence. Here, surface features such as colour (Experiments 1 and 2) or luminance (Experiment 3) were switched between the two objects at coincidence. The moment of coincidence was invisible to observers due to an occluder. Additionally, the presentation of the moving objects was manipulated in duration after the feature switch at coincidence. The results revealed that a postcoincidence duration of approximately 200 ms was required for the visual system to stabilize judgments of stream/bounce events by determining motion correspondence between the objects across the occlusion on the basis of the surface feature. The critical duration was similar across motion speeds of objects and types of surface features. Moreover, controls (Experiments 4a-4c) showed that cognitive bias based on feature (colour/luminance) congruency across the occlusion could not fully account for the effects of surface features on the stream/bounce judgments. We discuss the roles of motion correspondence, visual feature processing, and attentive tracking in the stream/bounce judgments.

  12. Stream/bounce event perception reveals a temporal limit of motion correspondence based on surface feature over space and time

    PubMed Central

    Kawachi, Yousuke; Kawabe, Takahiro; Gyoba, Jiro

    2011-01-01

    We examined how stream/bounce event perception is affected by motion correspondence based on the surface features of moving objects passing behind an occlusion. In the stream/bounce display two identical objects moving across each other in a two-dimensional display can be perceived as either streaming through or bouncing off each other at coincidence. Here, surface features such as colour (Experiments 1 and 2) or luminance (Experiment 3) were switched between the two objects at coincidence. The moment of coincidence was invisible to observers due to an occluder. Additionally, the presentation of the moving objects was manipulated in duration after the feature switch at coincidence. The results revealed that a postcoincidence duration of approximately 200 ms was required for the visual system to stabilize judgments of stream/bounce events by determining motion correspondence between the objects across the occlusion on the basis of the surface feature. The critical duration was similar across motion speeds of objects and types of surface features. Moreover, controls (Experiments 4a–4c) showed that cognitive bias based on feature (colour/luminance) congruency across the occlusion could not fully account for the effects of surface features on the stream/bounce judgments. We discuss the roles of motion correspondence, visual feature processing, and attentive tracking in the stream/bounce judgments. PMID:23145236

  13. Simultaneous teleseismic and geodetic observations of the stick-slip motion of an Antarctic ice stream.

    PubMed

    Wiens, Douglas A; Anandakrishnan, Sridhar; Winberry, J Paul; King, Matt A

    2008-06-05

    Long-period seismic sources associated with glacier motion have been recently discovered, and an increase in ice flow over the past decade has been suggested on the basis of secular changes in such measurements. Their significance, however, remains uncertain, as a relationship to ice flow has not been confirmed by direct observation. Here we combine long-period surface-wave observations with simultaneous Global Positioning System measurements of ice displacement to study the tidally modulated stick-slip motion of the Whillans Ice Stream in West Antarctica. The seismic origin time corresponds to slip nucleation at a region of the bed of the Whillans Ice Stream that is likely stronger than in surrounding regions and, thus, acts like an 'asperity' in traditional fault models. In addition to the initial pulse, two seismic arrivals occurring 10-23 minutes later represent stopping phases as the slip terminates at the ice stream edge and the grounding line. Seismic amplitude and average rupture velocity are correlated with tidal amplitude for the different slip events during the spring-to-neap tidal cycle. Although the total seismic moment calculated from ice rigidity, slip displacement, and rupture area is equivalent to an earthquake of moment magnitude seven (M(w) 7), seismic amplitudes are modest (M(s) 3.6-4.2), owing to the source duration of 20-30 minutes. Seismic radiation from ice movement is proportional to the derivative of the moment rate function at periods of 25-100 seconds and very long-period radiation is not detected, owing to the source geometry. Long-period seismic waves are thus useful for detecting and studying sudden ice movements but are insensitive to the total amount of slip.

  14. Effects of a Non-Circular Chainring on Sprint Performance During a Cycle Ergometer Test.

    PubMed

    Hintzy, Frédérique; Grappe, Frédéric; Belli, Alain

    2016-06-01

    Non-circular chainrings have been reported to alter the crank angular velocity profile over a pedal revolution so that more time is spent in the effective power phase. The purpose of this study was to determine whether sprint cycling performance could be improved using a non-circular chainring (Osymetric: ellipticity 1.25 and crank lever mounted nearly perpendicular to the major axis), in comparison with a circular chainring. Twenty sprint cyclists performed an 8 s sprint on a cycle ergometer against a 0.5 N/kg(-1) friction force in four crossing conditions (non-circular or circular chainring with or without clipless pedal). Instantaneous force, velocity and power were continuously measured during each sprint. Three main characteristic pedal downstrokes were selected: maximal force (in the beginning of the sprint), maximal power (towards the middle), and maximal velocity (at the end of the sprint). Both average and instantaneous force, velocity and power were calculated during the three selected pedal downstrokes. The important finding of this study was that the maximal power output was significantly higher (+ 4.3%, p < 0.05) when using the non-circular chainring independent from the shoe-pedal linkage condition. This improvement is mainly explained by a significantly higher instantaneous external force that occurs during the downstroke. Non-circular chainring can have potential benefits on sprint cycling performance. Key pointsThe Osymetric non-circular chainring significantly maximized crank power by 4.3% during sprint cycling, in comparison with a circular chainring.This maximal power output improvement was due to significant higher force developed when the crank was in the effective power phase.This maximal power output improvement was independent from the shoe-pedal linkage condition.Present benefits provided by the non-circular chainring on pedalling kinetics occurred only at high cadences.

  15. Effects of a Non-Circular Chainring on Sprint Performance During a Cycle Ergometer Test

    PubMed Central

    Hintzy, Frédérique; Grappe, Frédéric; Belli, Alain

    2016-01-01

    Non-circular chainrings have been reported to alter the crank angular velocity profile over a pedal revolution so that more time is spent in the effective power phase. The purpose of this study was to determine whether sprint cycling performance could be improved using a non-circular chainring (Osymetric: ellipticity 1.25 and crank lever mounted nearly perpendicular to the major axis), in comparison with a circular chainring. Twenty sprint cyclists performed an 8 s sprint on a cycle ergometer against a 0.5 N/kg-1 friction force in four crossing conditions (non-circular or circular chainring with or without clipless pedal). Instantaneous force, velocity and power were continuously measured during each sprint. Three main characteristic pedal downstrokes were selected: maximal force (in the beginning of the sprint), maximal power (towards the middle), and maximal velocity (at the end of the sprint). Both average and instantaneous force, velocity and power were calculated during the three selected pedal downstrokes. The important finding of this study was that the maximal power output was significantly higher (+ 4.3%, p < 0.05) when using the non-circular chainring independent from the shoe-pedal linkage condition. This improvement is mainly explained by a significantly higher instantaneous external force that occurs during the downstroke. Non-circular chainring can have potential benefits on sprint cycling performance. Key points The Osymetric non-circular chainring significantly maximized crank power by 4.3% during sprint cycling, in comparison with a circular chainring. This maximal power output improvement was due to significant higher force developed when the crank was in the effective power phase. This maximal power output improvement was independent from the shoe-pedal linkage condition. Present benefits provided by the non-circular chainring on pedalling kinetics occurred only at high cadences. PMID:27274658

  16. KINEMATICS IN KAPTEYN'S SELECTED AREA 76: ORBITAL MOTIONS WITHIN THE HIGHLY SUBSTRUCTURED ANTICENTER STREAM

    SciTech Connect

    Carlin, Jeffrey L.; Majewski, Steven R.; Casetti-Dinescu, Dana I.; Girard, Terrence M.; Grillmair, Carl J. E-mail: srm4n@virginia.ed E-mail: girard@astro.yale.ed

    2010-12-20

    We have measured the mean three-dimensional kinematics of stars in Kapteyn's Selected Area (SA) 76 (l = 209.{sup 0}3, b = 26.{sup 0}4) that were selected to be Anticenter Stream (ACS) members on the basis of their radial velocities (RVs), proper motions (PMs), and location in the color-magnitude diagram. From a total of 31 stars ascertained to be ACS members primarily from its main-sequence turnoff, a mean ACS RV (derived from spectra obtained with the Hydra multi-object spectrograph on the WIYN 3.5 m telescope) of V{sub helio} = 97.0 {+-} 2.8 km s{sup -1} was determined, with an intrinsic velocity dispersion {sigma}{sub o} = 12.8 {+-} 2.1 km s{sup -1}. The mean absolute PMs of these 31 ACS members are {mu}{sub {alpha}} cos {delta} = -1.20 {+-} 0.34 mas yr{sup -1} and {mu}{sub {delta}} = -0.78 {+-} 0.36 mas yr{sup -1}. At a distance to the ACS of 10 {+-} 3 kpc, these measured kinematical quantities produce an orbit that deviates by {approx}30{sup 0} from the well-defined swath of stellar overdensity constituting the ACS in the western portion of the Sloan Digital Sky Survey footprint. We explore possible explanations for this and suggest that our data in SA 76 are measuring the motion of a kinematically cold sub-stream among the ACS debris that was likely a fragment of the same infalling structure that created the larger ACS system. The ACS is clearly separated spatially from the majority of claimed Monoceros ring detections in this region of the sky; however, with the data in hand, we are unable to either confirm or rule out an association between the ACS and the poorly understood Monoceros structure.

  17. Bedload transport in steep glacier-fed streams: from incipient motion to floods

    NASA Astrophysics Data System (ADS)

    Comiti, Francesco; Dell'Agnese, Andrea; Lucia, Ana; Vignoli, Gianluca; Simoni, Silvia; Bertoldi, Walter; Mao, Luca; Macconi, Pierpaolo; Mazzorana, Bruno; Dinale, Roberto

    2015-04-01

    The current understanding of bedload dynamics in mountain channels is rather scarce, and the capability to predict it over a range of discharges and under different morphological conditions is still very poor despite the headways made during the last decade. Indeed, there has been an increased recognition of the highly stochastic nature of bedload transport in steep streams, especially at low to medium flows (i.e. up to ordinary events). On the other hand, considerable efforts have been made to model the effective energy available for bedload in steep channels, in order to reduce the large overestimation in bedload rates produced by transport capacity equations. Nonetheless, because high-gradient channels are notoriously sediment supply-limited, largely varying bedload rates can be observed at the same stream cross-section under nearly identical morphological and hydraulic conditions, as a consequence of different sediment supply regimes/events. Therefore, the use of a single bedload transport equation even for the same stream is becoming strongly questioned by researchers, whereas most river agencies and consultants - and numerical models - still rely on "classical" transport capacity equations. Remarkably, glacial streams offer the possibility to investigate how seasonal changes in sediment supply at the basin scale - deriving from the periglacial and glacial areas - affects bedload transport rates in the main channel. However, little quantitative bedload data from these systems are available. This contribution intends to share the recent results obtained in two glaciarized basins in the Eastern Italian Alps, which range from about 10 km2 (upper Saldur river basin) to 130 km2 (Sulden river basin) in drainage area. Different monitoring methodologies encompassing PIT-tagged clasts tracking (by both portable and stationary antennas), geophone plates, acoustic pipe sensor and direct sampling by portable traps have been deployed in these two mountain streams. Our

  18. Tidally induced variations in vertical and horizontal motion on Rutford Ice Stream, West Antarctica, inferred from remotely sensed observations

    NASA Astrophysics Data System (ADS)

    Minchew, B. M.; Simons, M.; Riel, B.; Milillo, P.

    2017-01-01

    To better understand the influence of stress changes over floating ice shelves on grounded ice streams, we develop a Bayesian method for inferring time-dependent 3-D surface velocity fields from synthetic aperture radar (SAR) and optical remote sensing data. Our specific goal is to observe ocean tide-induced variability in vertical ice shelf position and horizontal ice stream flow. Thus, we consider the special case where observed surface displacement at a given location can be defined by a 3-D secular velocity vector, a family of 3-D sinusoidal functions, and a correction to the digital elevation model used to process the SAR data. Using nearly 9 months of SAR data collected from multiple satellite viewing geometries with the COSMO-SkyMed 4-satellite constellation, we infer the spatiotemporal response of Rutford Ice Stream, West Antarctica, to ocean tidal forcing. Consistent with expected tidal uplift, inferred vertical motion over the ice shelf is dominated by semidiurnal and diurnal tidal constituents. Horizontal ice flow variability, on the other hand, occurs primarily at the fortnightly spring-neap tidal period (Msf). We propose that periodic grounding of the ice shelf is the primary mechanism for translating vertical tidal motion into horizontal flow variability, causing ice flow to accelerate first and most strongly over the ice shelf. Flow variations then propagate through the grounded ice stream at a mean rate of ˜29 km/d and decay quasi-linearly with distance over ˜85 km upstream of the grounding zone.

  19. Performance limits of ion extraction systems with non-circular apertures

    NASA Astrophysics Data System (ADS)

    Shagayda, A.; Madeev, S.

    2016-04-01

    A three-dimensional computer simulation is used to determine the perveance limitations of ion extraction systems with non-circular apertures. The objective of the study is to analyze the possibilities to improve mechanical strength of the ion optics made of carbon-carbon composite materials. Non-circular grid apertures are better suited to the physical structure of carbon-carbon composite materials, than conventionally used circular holes in a hexagonal pattern, because they allow a fewer number of cut fibers. However, the slit-type accelerating systems, usually regarded as the main alternative to the conventional ion optics, have an intolerably narrow range of operating perveance values at which there is no direct ion impingement on the acceleration grid. This paper presents results of comparative analysis of a number of different ion optical systems with non-circular apertures and conventional ion optical systems with circular apertures. It has been revealed that a relatively wide perveance range without direct ion impingement may be obtained with apertures shaped as a square with rounded corners. Numerical simulations show that this geometry may have equivalent perveance range as the traditional geometry with circular apertures while being more mechanically robust. In addition, such important characteristics, as the effective transparency for both the ions and the neutral atoms, the height of the potential barrier reflecting the downstream plasma electrons and the angular divergence of the beamlet also can be very close to these parameters for the optics with circular apertures.

  20. Dorsal and ventral stream contributions to form-from-motion perception in a patient with form-from motion deficit: a case report.

    PubMed

    Mercier, Manuel R; Schwartz, Sophie; Spinelli, Laurent; Michel, Christoph M; Blanke, Olaf

    2017-03-01

    The main model of visual processing in primates proposes an anatomo-functional distinction between the dorsal stream, specialized in spatio-temporal information, and the ventral stream, processing essentially form information. However, these two pathways also communicate to share much visual information. These dorso-ventral interactions have been studied using form-from-motion (FfM) stimuli, revealing that FfM perception first activates dorsal regions (e.g., MT+/V5), followed by successive activations of ventral regions (e.g., LOC). However, relatively little is known about the implications of focal brain damage of visual areas on these dorso-ventral interactions. In the present case report, we investigated the dynamics of dorsal and ventral activations related to FfM perception (using topographical ERP analysis and electrical source imaging) in a patient suffering from a deficit in FfM perception due to right extrastriate brain damage in the ventral stream. Despite the patient's FfM impairment, both successful (observed for the highest level of FfM signal) and absent/failed FfM perception evoked the same temporal sequence of three processing states observed previously in healthy subjects. During the first period, brain source localization revealed cortical activations along the dorsal stream, currently associated with preserved elementary motion processing. During the latter two periods, the patterns of activity differed from normal subjects: activations were observed in the ventral stream (as reported for normal subjects), but also in the dorsal pathway, with the strongest and most sustained activity localized in the parieto-occipital regions. On the other hand, absent/failed FfM perception was characterized by weaker brain activity, restricted to the more lateral regions. This study shows that in the present case report, successful FfM perception, while following the same temporal sequence of processing steps as in normal subjects, evoked different patterns of

  1. Does a Non-Circular Chainring Improve Performance in the Bicycle Motocross Cycling Start Sprint?

    PubMed Central

    Mateo-March, Manuel; Fernández-Peña, Eneko; Blasco-Lafarga, Cristina; Morente-Sánchez, Jaime; Zabala, Mikel

    2014-01-01

    Maximising power output during the initial acceleration phase of a bicycle motocross (BMX) race increases the chance to lead the group for the rest of the race. The purpose of this study was to investigate the effect of non-circular chainrings (Q-ring) on performance during the initial acceleration phase of a BMX race. Sixteen male cyclists (Spanish National BMX team) performed two counterbalanced and randomized initial sprints (3.95s), using Q- ring vs. circular chainring, on a BMX track. The sample was divided into two different groups according to their performance (Elite; n = 8 vs. Cadet; n = 8). Elite group covered a greater distance using Q-ring (+0.26 m, p = 0.02; D = 0.23), whilst the improvement for the Cadet (+0.04 m) was not significant (p = 0.87; D = -0.02). Also, there was no significant difference in power output for the Elite group, while the Cadet group revealed larger peak power with the circular chainring. Neither lactate level, nor heart rate showed significant differences due to the different chainring used. The non-circular chainring improved the initial acceleration capacity only in the Elite riders. Key Points This work provides novel results demonstrating very significant improvements in the sprint performance of BMX cycling discipline using a non-circular chainring system. This study seeks a practical application from scientific analysis All data are obtained in a real context of high competition using a sample comprised by the National Spanish Team. Some variables influencing performance as subjects’ physical fitness are discussed. Technical equipment approved by International Cycling Union is studied to check its potentially beneficial influence on performance. PMID:24570612

  2. Experiments in dilution jet mixing effects of multiple rows and non-circular orifices

    NASA Technical Reports Server (NTRS)

    Holdeman, J. D.; Srinivasan, R.; Coleman, E. B.; Meyers, G. D.; White, C. D.

    1985-01-01

    Experimental and empirical model results are presented that extend previous studies of the mixing of single-sided and opposed rows of jets in a confined duct flow to include effects of non-circular orifices and double rows of jets. Analysis of the mean temperature data obtained in this investigation showed that the effects of orifice shape and double rows are significant only in the region close to the injection plane, provided that the orifices are symmetric with respect to the main flow direction. The penetration and mixing of jets from 45-degree slanted slots is slightly less than that from equivalent-area symmetric orifices. The penetration from 2-dimensional slots is similar to that from equivalent-area closely-spaced rows of holes, but the mixing is slower for the 2-D slots. Calculated mean temperature profiles downstream of jets from non-circular and double rows of orifices, made using an extension developed for a previous empirical model, are shown to be in good agreement with the measured distributions.

  3. Hubble Space Telescope Proper Motions along the Sagittarius Stream. I. Observations and Results for Stars in Four Fields

    NASA Astrophysics Data System (ADS)

    Sohn, Sangmo Tony; van der Marel, Roeland P.; Carlin, Jeffrey L.; Majewski, Steven R.; Kallivayalil, Nitya; Law, David R.; Anderson, Jay; Siegel, Michael H.

    2015-04-01

    We present a multi-epoch Hubble Space Telescope (HST) study of stellar proper motions (PMs) for four fields spanning 200° along the Sagittarius (Sgr) stream: one trailing arm field, one field near the Sgr dwarf spheroidal tidal radius, and two leading arm fields. We determine absolute PMs of dozens of individual stars per field, using established techniques that use distant background galaxies as the stationary reference frame. Stream stars are identified based on combined color-magnitude diagram and PM information. The results are broadly consistent with the few existing PM measurements for the Sgr galaxy and the trailing arm. However, our new results provide the highest PM accuracy for the stream to date, the first PM measurements for the leading arm, and the first PM measurements for individual stream stars; we also serendipitously determine the PM of the globular cluster NGC 6652. In the trailing-arm field, the individual PMs allow us to kinematically separate trailing-arm stars from leading-arm stars that are 360° further ahead in their orbit. Also, in three of our fields we find indications that two distinct kinematical components may exist within the same arm and wrap of the stream. Qualitative comparison of the HST data to the predictions of the Law & Majewski and Peñarrubia et al. N-body models show that the PM measurements closely follow the predicted trend with Sgr longitude. This provides a successful consistency check on the PM measurements, as well as on these N-body approaches (which were not tailored to fit any PM data).

  4. Experimental procedure for the study of liquid bridges between non-circular disks

    NASA Astrophysics Data System (ADS)

    Cabezas, M. G.; Herrera, J. M.; Montanero, J. M.

    A liquid bridge is a mass of liquid sustained by the action of the surface tension force between two parallel supporting solids. Apart from its intrinsic basic science interest, the study of liquid bridges has an undoubted technological relevance. Indeed, this fluid configuration has traditionally been seen as an idealization of that appearing in the crystal growth technique known as floating-zone melting, which is used in fabricating ultrapure semiconductor crystals. This has conferred to the analysis of liquid bridges great interest not only in fluid mechanics but also in the material engineering field. As far as the static problem is concerned, studies have focused on the calculation of both the liquid bridge equilibrium interface shape and the stability limits. Most of these studies deal with liquid bridges held between two circular disks, though a few theoretical works with non-circular disks have been published recently. In experiments with liquid bridges, the neutral buoyancy technique has frequently been used to simulate microgravity conditions. In this technique, the liquid bridge is surrounded by an outer liquid with similar density to compensate partially for the effect of the hydrostatic pressure over the interface. Here, a crucial aspect is the accurate knowledge of the surface tension value associated to the interface. In the present contribution, an experimental procedure for analysing the behaviour of liquid bridges between non circular disks is presented. The experiments are performed using the buoyancy technique with a cell designed specifically for this purpose. Two liquid bridges are formed inside the cell. The first one is supported by two circular disks and it is used to measure the surface tension associated to the interface between the fluids involved. To this end, a digital image of the liquid bridge is taken using the ideal conditions (gravity and the axis of the liquid bridge are perpendicular to each other, and the view is frontal

  5. A mechanistic model linking insect (Hydropsychidae) silk nets to incipient sediment motion in gravel-bedded streams

    NASA Astrophysics Data System (ADS)

    Albertson, Lindsey K.; Sklar, Leonard S.; Pontau, Patricia; Dow, Michelle; Cardinale, Bradley J.

    2014-09-01

    Plants and animals affect stream morphodynamics across a range of scales, yet including biological traits of organisms in geomorphic process models remains a fundamental challenge. For example, laboratory experiments have shown that silk nets built by caddisfly larvae (Trichoptera: Hydropsychidae) can increase the shear stress required to initiate bed motion by more than a factor of 2. The contributions of specific biological traits are not well understood, however. Here we develop a theoretical model for the effects of insect nets on the threshold of sediment motion, τ*crit, that accounts for the mechanical properties, geometry, and vertical distribution of insect silk, as well as interactions between insect species. To parameterize the model, we measure the tensile strength, diameter, and number of silk threads in nets built by two common species of caddisfly, Arctopsyche californica and Ceratopsyche oslari. We compare model predictions with new measurements of τ*crit in experiments where we varied grain size and caddisfly species composition. The model is consistent with experimental results for single species, which show that the increase in τ*crit above the abiotic control peaks at 40-70% for 10-22 mm sediments and declines with increasing grain size. For the polyculture experiments, however, the model underpredicts the measured increase in τ*crit when two caddisfly species are present in sediments of larger grain sizes. Overall, the model helps explain why the presence of caddisfly silk can substantially increase the forces needed to initiate sediment motion in gravel-bedded streams and also illustrates the challenge of parameterizing the behavior of multiple interacting species in a physical model.

  6. Interface and process for enhanced transmission of non-circular ion beams between stages at unequal pressure

    DOEpatents

    Tang, Keqi; Shvartsburg, Alexandre A.; Smith, Richard D.

    2008-03-04

    The invention discloses a new interface with non-circular conductance limit aperture(s) useful for effective transmission of non-circular ion beams between stages with different gas pressure. In particular, the invention provides an improved coupling of field asymmetric waveform ion mobility spectrometry (FAIMS) analyzers of planar or side-to-side geometry to downstream stages such as mass spectrometry or ion mobility spectrometry. In this case, the non-circular aperture is rectangular; other geometries may be optimum in other applications. In the preferred embodiment, the non-circular aperture interface is followed by an electrodynamic ion funnel that may focus wide ion beams of any shape into tight circular beams with virtually no losses. The jet disrupter element of the funnel may also have a non-circular geometry, matching the shape of arriving ion beam. The improved sensitivity of planar FAIMS/MS has been demonstrated in experiments using a non-contiguous elongated aperture but other embodiments (e.g., with a contiguous slit aperture) may be preferable, especially in conjunction with an ion funnel operated at high pressures.

  7. WE-G-BRF-07: Non-Circular Scanning Trajectories with Varian Developer Mode

    SciTech Connect

    Davis, A; Pearson, E; Pan, X; Pelizzari, C

    2014-06-15

    Purpose: Cone-beam CT (CBCT) in image-guide radiation therapy (IGRT) typicallyacquires scan data via the circular trajectory of the linearaccelerator's (linac) gantry rotation. Though this lends itself toanalytic reconstruction algorithms like FDK, iterative reconstructionalgorithms allow for a broader range of scanning trajectories. Weimplemented a non-circular scanning trajectory with Varian's TrueBeamDeveloper Mode and performed some preliminary reconstructions toverify the geometry. Methods: We used TrueBeam Developer Mode to program a new scanning trajectorythat increases the field of view (FOV) along the gantry rotation axiswithout moving the patient. This trajectory consisted of moving thegantry in a circle, then translating the source and detector along theaxial direction before acquiring another circular scan 19 cm away fromthe first. The linear portion of the trajectory includes an additional4.5 cm above and below the axial planes of the source's circularrotation. We scanned a calibration phantom consisting of a lucite tubewith a spiral pattern of CT spots and used the maximum-likelihoodalgorithm to iteratively reconstruct the CBCT volume. Results: With the TrueBeam trajectory definition, we acquired projection dataof the calibration phantom using the previously described trajectory.We obtained a scan of the treatment couch for log normalization byscanning with the same trajectory but without the phantom present.Using the nominal geometric parameters reported in the projectionheaders with our iterative reconstruction algorithm, we obtained acorrect reconstruction of the calibration phantom. Conclusion: The ability to implement new scanning trajectories with the TrueBeamDeveloper Mode enables us access to a new parameter space for imagingwith CBCT for IGRT. Previous simulations and simple dual circle scanshave shown iterative reconstruction with non-circular trajectories canincrease the axial FOV with CBCT. Use of Developer Mode allowsexperimentally

  8. Beam quality M 2 factor matrix for non-circular symmetric laser beams

    NASA Astrophysics Data System (ADS)

    Du, Yongzhao; Fu, Yuqing; Zheng, Chaoying

    2017-02-01

    It is standard to use Mx2 and My2 to characterize the beam quality of a non-circular symmetrical beam on its x-axis and y-axis orientation. However, we knew that the values of Mx2 and My2 are inconsistent if one selects a different coordinate system or measures beam quality with different experimental conditionals, even when analyzing the same beam. To overcome this, a new beam quality characterization method, the M 2 factor matrix, is developed. It not only contains the beam quality terms, Mx2 and My2 , to characterize the beam quality along x-axis and y-axis orientation for the non-symmetric beam, but also introduces two additional cross terms, M xy and M yx , which are used to characterize the location relationship between the principal axis of the test beam and coordinate system in experiment. Moreover, M 2 factor matrix can be measured with a similar procedure to the traditional M 2 factor whose measurement instructions are described in ISO11146 by adding some additional image and signal processing procedure. The measurement principle and method is present and the experiment system for beam quality M 2 factor matrix is built to demonstrate the performance of M 2 factor matrix with real experiments.

  9. Motion.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    2002-01-01

    This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

  10. Motion.

    ERIC Educational Resources Information Center

    Gerhart, James B.; Nussbaum, Rudi H.

    This monograph was written for the Conference on the New Instructional Materials in Physics held at the University of Washington in summer, 1965. It is intended for use in an introductory course in college physics. It consists of an extensive qualitative discussion of motion followed by a detailed development of the quantitative methods needed to…

  11. Transfrontier macroseismic data exchange in NW Europe: examples of non-circular intensity distributions

    NASA Astrophysics Data System (ADS)

    Van Noten, Koen; Lecocq, Thomas; Hinzen, Klaus-G.; Sira, Christophe; Camelbeeck, Thierry

    2016-04-01

    Macroseismic data acquisition recently received a strong increase in interest due to public crowdsourcing through internet-based inquiries and real-time smartphone applications. Macroseismic analysis of felt earthquakes is important as the perception of people can be used to detect local/regional site effects in areas without instrumentation. We will demonstrate how post-processing macroseismic data improves the quality of real-time intensity evaluation of new events. Instead of using the classic DYFI representation in which internet intensities are averaged per community, we, first, geocoded all individual responses and structure the model area into 100 km2grid cells. Second, the average intensity of all answers within a grid cell is calculated. The resulting macroseismic grid cell distribution shows a less subjective and more homogeneous intensity distribution than the classical irregular community distribution and helps to improve the calculation of intensity attenuation functions. In this presentation, the 'Did You Feel It' (DYFI) macroseismic data of several >M4, e.g. the 2002 ML 4.9 Alsdorf and 2011 ML 4.3 Goch (Germany) and the 2015 ML 4.1 Ramsgate (UK), earthquakes felt in Belgium, Germany, The Netherlands, France, Luxemburg and UK are analysed. Integration of transfrontier DYFI data of the ROB-BNS, KNMI, BCSF and BGS networks results in a particular non-circular, distribution of the macroseismic data in which the felt area for all these examples extends significantly more in E-W than N-S direction. This intensity distribution cannot be explained by geometrical amplitude attenuation alone, but rather illustrates a low-pass filtering effect due to the south-to-north increasing thickness of cover sediments above the London-Brabant Massif. For the studied M4 to M5 earthquakes, the thick sediments attenuate seismic energy at higher frequencies and consequently less people feel the vibrations at the surface. This example of successful macroseismic data exchange

  12. SU-E-I-02: Characterizing Low-Contrast Resolution for Non-Circular CBCT Trajectories

    SciTech Connect

    Davis, A; Pan, X; Pelizzari, C; Pearson, E

    2015-06-15

    Purpose: The use of non-circular scanning trajectories with optimization-basedreconstruction algorithms can be used in conjunction with non-planaracquisition geometries for axial field-of-view (FOV) extension incone-beam CT (CBCT). To evaluate the utility of these trajectories,quantitative image quality metrics should be evaluated. Low-contrastresolution (LCR) and CT number accuracy are significant challenges forCBCT. With unprecedented axial coverage provided by thesetrajectories, measuring such metrics throughout the axial range iscritical. There are currently no phantoms designed to measurelow-contrast resolution over such an extended volume. Methods: The CATPHAN (The Phantom Laboratory, Salem NY) is the current standardfor image quality evaluation. While providing several useful modulesfor different evaluation metrics, each module was designed to beevaluated in a single slice and not for comparison across axialpositions. To characterize the LCR and HU accuracy over an extendedaxial length, we have designed and built a phantom with evaluationmodules at multiple and adjustable axial positions. Results: The modules were made from a cast polyurethane resin. Holes rangingfrom 1/8 to 5/8 inch were added at a constant radius from the modulecenter into which rods of two different plastic materials were pressedto provide two nominal levels of contrast (1.0% and 0.5%). Largerholes were bored to accept various RMI plugs with known electrondensities for HU accuracy evaluation. The modules can be inserted intoan acrylic tube long enough to cover the entire axial FOV and theirpositions adjusted to desired evaluation points. Conclusion: This phantom allows us to measure the LCR and HU accuracy across theaxial coverage within a single acquisition. These metrics can be usedto characterize the impact different trajectories and reconstructionparameters have on clinically relevant image quality performancemetrics. Funding was provided in part by Varian Medical Systems and NIH R01

  13. Comparative Study on Interaction of Form and Motion Processing Streams by Applying Two Different Classifiers in Mechanism for Recognition of Biological Movement

    PubMed Central

    2014-01-01

    Research on psychophysics, neurophysiology, and functional imaging shows particular representation of biological movements which contains two pathways. The visual perception of biological movements formed through the visual system called dorsal and ventral processing streams. Ventral processing stream is associated with the form information extraction; on the other hand, dorsal processing stream provides motion information. Active basic model (ABM) as hierarchical representation of the human object had revealed novelty in form pathway due to applying Gabor based supervised object recognition method. It creates more biological plausibility along with similarity with original model. Fuzzy inference system is used for motion pattern information in motion pathway creating more robustness in recognition process. Besides, interaction of these paths is intriguing and many studies in various fields considered it. Here, the interaction of the pathways to get more appropriated results has been investigated. Extreme learning machine (ELM) has been implied for classification unit of this model, due to having the main properties of artificial neural networks, but crosses from the difficulty of training time substantially diminished in it. Here, there will be a comparison between two different configurations, interactions using synergetic neural network and ELM, in terms of accuracy and compatibility. PMID:25276860

  14. Sediment Mobilization and Storage Dynamics of a Debris Flow Impacted Stream Channel using Multi-Temporal Structure from Motion Photogrammetry

    NASA Astrophysics Data System (ADS)

    Bailey, T. L.; Sutherland-Montoya, D.

    2015-12-01

    High resolution topographic analysis methods have become important tools in geomorphology. Structure from Motion photogrammetry offers a compelling vehicle for geomorphic change detection in fluvial environments. This process can produce arbitrarily high resolution, geographically registered spectral and topographic coverages from a collection of overlapping digital imagery from consumer cameras. Cuneo Creek has had three historically observed episodes of rapid aggradation (1955, 1964, and 1997). The debris flow deposits continue to be major sources of sediment sixty years after the initial slope failure. Previous studies have monitored the sediment storage volume and particle size since 1976 (in 1976, 1982, 1983, 1985, 1986, 1987, 1998, 2003). We reoccupied 3 previously surveyed stream cross sections on Sept 30, 2014 and March 30, 2015, and produced photogrammetric point clouds using a pole mounted camera with a remote view finder to take nadir view images from 4.3 meters above the channel bed. Ground control points were registered using survey grade GPS and typical cross sections used over 100 images to build the structure model. This process simultaneously collects channel geometry and we used it to also generate surface texture metrics, and produced DEMs with point cloud densities above 5000 points / m2. In the period between the surveys, a five year recurrence interval discharge of 20 m3/s scoured the channel. Surface particle size distribution has been determined for each observation period using image segmentation algorithms based on spectral distance and compactness. Topographic differencing between the point clouds shows substantial channel bed mobilization and reorganization. The net decline in sediment storage is in excess of 4 x 10^5 cubic meters since the 1964 aggradation peak, with associated coarsening of surface particle sizes. These new methods provide a promising rapid assessment tool for measurement of channel responses to sediment inputs.

  15. Fabrication of dense non-circular nanomagnetic device arrays using self-limiting low-energy glow-discharge processing.

    PubMed

    Zheng, Zhen; Chang, Long; Nekrashevich, Ivan; Ruchhoeft, Paul; Khizroev, Sakhrat; Litvinov, Dmitri

    2013-01-01

    We describe a low-energy glow-discharge process using reactive ion etching system that enables non-circular device patterns, such as squares or hexagons, to be formed from a precursor array of uniform circular openings in polymethyl methacrylate, PMMA, defined by electron beam lithography. This technique is of a particular interest for bit-patterned magnetic recording medium fabrication, where close packed square magnetic bits may improve its recording performance. The process and results of generating close packed square patterns by self-limiting low-energy glow-discharge are investigated. Dense magnetic arrays formed by electrochemical deposition of nickel over self-limiting formed molds are demonstrated.

  16. Coupling analysis of non-circular-symmetric modes and design of orientation-insensitive few-mode fiber couplers

    NASA Astrophysics Data System (ADS)

    Li, Jiaxiong; Du, Jiangbing; Ma, Lin; Li, Ming-Jun; Jiang, Shoulin; Xu, Xiao; He, Zuyuan

    2017-01-01

    We study the coupling between two identical weakly-coupled few-mode fibers based on coupled-mode theory. The coupling behavior of non-circular-symmetric modes, such as LP11 and LP21, is investigated analytically and numerically. By carefully choosing the fiber core separation and coupler length, we can design orientation-insensitive fiber couplers for non-circular-symmetric modes at arbitrary coupling ratios. Based on the design method, we propose an orientation-insensitive two-mode fiber coupler at 850 nm working as a mode multiplexer/demultiplexer for two-mode transmission using standard single-mode fiber. Within the band from 845 to 855 nm, the insertion losses of LP01 and LP11 modes are less than 0.03 dB and 0.24 dB, respectively. When the two-mode fiber coupler is used as mode demultiplexer, the LP01/LP11 and LP11/LP01 extinction ratios in the separated branches are respectively above 12.6 dB and 21.2 dB. Our design method can be extended to two-mode communication or sensing systems at other wavelengths.

  17. Broadband light source based on highly nonlinear non-circular core photonic crystal fiber for medical applications

    NASA Astrophysics Data System (ADS)

    Islam, M. A.; Hossain, M. A.

    2012-11-01

    We present a highly nonlinear non-circular core photonic crystal fiber (HNL-NCPCF) with all normal group velocity dispersion (GVD) to design a supercontinuum (SC) light source for optical coherence tomography (OCT) system. Nonlinear coefficient γ is increased as large as 66 W-1 km-1 at 1.31 μm by reducing the effective mode area and core is made non-circular to increase birefringence by putting the square lattice of air-holes inside the silica host. About 85 nm 10 dB spectral bandwidths for 2.5 ps input optical pulse and 140 nm 10 dB spectral bandwidths for 1.0 ps input optical pulse have been observed using the same fiber length of 200 m and input optical power of 15 W. Coherent lengths of the generated supercontinuum light sources are found 8.91 μm for 2.5 ps input optical pulse and 5.41 μm for 1.0 ps input optical pulse. Therefore, the highest longitudinal resolution for dental OCT at 1.31 μm is found about 3.28 μm for tooth enamel.

  18. EFFECT OF STREAMING MOTION OF BARYONS RELATIVE TO DARK MATTER ON THE FORMATION OF THE FIRST STARS

    SciTech Connect

    Stacy, Athena; Bromm, Volker; Loeb, Abraham

    2011-03-20

    We evaluate the effect of a supersonic relative velocity between the baryons and dark matter on the thermal and density evolution of the first gas clouds at z {approx}< 50. Through a series of cosmological simulations, initialized at z{sub i} = 100 with a range of relative streaming velocities and minihalo formation redshifts, we find that the typical streaming velocities will have little effect on the gas evolution. Once the collapse begins, the subsequent evolution of the gas will be nearly indistinguishable from the case of no streaming, and star formation will still proceed in the same way, with no change in the characteristic Pop III stellar masses. Reionization is expected to be dominated by halo masses of {approx}>10{sup 8} M{sub sun}, for which the effect of streaming should be negligible.

  19. Structure Damage Simulations Accounting for Inertial Effects and Impact and Optimization of Grid-Stiffened Non-Circular Shells

    NASA Technical Reports Server (NTRS)

    Mei, Chuh; Jaunky, Navin

    1999-01-01

    The goal of this research project is to develop modelling and analysis strategy for the penetration of aluminium plates impacted by titanium impactors. Finite element analysis is used to study the penetration of aluminium plates impacted by titanium impactors in order to study the effect of such uncontained engine debris impacts on aircraft-like skin panels. LS-DYNA3D) is used in the simulations to model the impactor, test fixture frame and target barrier plate. The effects of mesh refinement, contact modeling, and impactor initial velocity and orientation were studied. The research project also includes development of a design tool for optimum design of grid-stiffened non-circular shells or panels subjected to buckling.

  20. Propagation and deposition of non-circular finite release particle-laden currents

    NASA Astrophysics Data System (ADS)

    Zgheib, Nadim; Bonometti, Thomas; Balachandar, S.

    2015-08-01

    The dynamics of non-axisymmetric turbidity currents is considered here for a range of Reynolds numbers of O (104) when based on the initial height of the release. The study comprises a series of experiments and highly resolved simulations for which a finite volume of particle-laden solution is released into fresh water. A mixture of water and polystyrene particles of mean diameter d ˜ p = 300 μ m and mixture density ρ ˜ c = 1012 kg / m 3 is initially confined in a hollow cylinder at the centre of a large tank filled with fresh water. Cylinders with two different cross-sectional shapes, but equal cross-sectional areas, are examined: a circle and a rounded rectangle in which the sharp corners are smoothened. The time evolution of the front is recorded as well as the spatial distribution of the thickness of the final deposit via the use of a laser triangulation technique. The dynamics of the front and final deposits are significantly influenced by the initial geometry, displaying substantial azimuthal variation especially for the rectangular case where the current extends farther and deposits more particles along the initial minor axis of the rectangular cross section. Several parameters are varied to assess the dependence on the settling velocity, initial height aspect ratio, and volume fraction. Even though resuspension is not taken into account in our simulations, good agreement with experiments indicates that it does not play an important role in the front dynamics, in terms of velocity and extent of the current. However, wall shear stress measurements show that incipient motion of particles and particle transport along the bed are likely to occur in the body of the current and should be accounted to properly capture the final deposition profile of particles.

  1. RESONANT STRUCTURE IN THE DISKS OF SPIRAL GALAXIES, USING PHASE REVERSALS IN STREAMING MOTIONS FROM TWO-DIMENSIONAL H{alpha} FABRY-PEROT SPECTROSCOPY

    SciTech Connect

    Font, Joan; Beckman, John E.; Fathi, Kambiz; Gutierrez, Leonel; Hernandez, Olivier E-mail: jeb@iac.es E-mail: kambiz@astro.su.se E-mail: hernandez@astro.umontreal.ca

    2011-11-01

    In this Letter, we introduce a technique for finding resonance radii in a disk galaxy. We use a two-dimensional velocity field in H{alpha} emission obtained with Fabry-Perot interferometry, derive the classical rotation curve, and subtract it off, leaving a residual velocity map. As the streaming motions should reverse sign at corotation, we detect these reversals and plot them in a histogram against galactocentric radius, excluding points where the amplitude of the reversal is smaller than the measurement uncertainty. The histograms show well-defined peaks which we assume to occur at resonance radii, identifying corotations as the most prominent peaks corresponding to the relevant morphological features of the galaxy (notably bars and spiral arm systems). We compare our results with published measurements on the same galaxies using other methods and different types of data.

  2. Estimating statistical isotropy violation in CMB due to non-circular beam and complex scan in minutes

    SciTech Connect

    Pant, Nidhi; Das, Santanu; Mitra, Sanjit; Souradeep, Tarun; Rotti, Aditya E-mail: santanud@iucaa.ernet.in E-mail: sanjit@iucaa.in

    2016-03-01

    Mild, unavoidable deviations from circular-symmetry of instrumental beams along with scan strategy can give rise to measurable Statistical Isotropy (SI) violation in Cosmic Microwave Background (CMB) experiments. If not accounted properly, this spurious signal can complicate the extraction of other SI violation signals (if any) in the data. However, estimation of this effect through exact numerical simulation is computationally intensive and time consuming. A generalized analytical formalism not only provides a quick way of estimating this signal, but also gives a detailed understanding connecting the leading beam anisotropy components to a measurable BipoSH characterisation of SI violation. In this paper, we provide an approximate generic analytical method for estimating the SI violation generated due to a non-circular (NC) beam and arbitrary scan strategy, in terms of the Bipolar Spherical Harmonic (BipoSH) spectra. Our analytical method can predict almost all the features introduced by a NC beam in a complex scan and thus reduces the need for extensive numerical simulation worth tens of thousands of CPU hours into minutes long calculations. As an illustrative example, we use WMAP beams and scanning strategy to demonstrate the easability, usability and efficiency of our method. We test all our analytical results against that from exact numerical simulations.

  3. Kurtosis-based blind source extraction of complex non-circular signals with application in EEG artifact removal in real-time.

    PubMed

    Javidi, Soroush; Mandic, Danilo P; Took, Clive Cheong; Cichocki, Andrzej

    2011-01-01

    A new class of complex domain blind source extraction algorithms suitable for the extraction of both circular and non-circular complex signals is proposed. This is achieved through sequential extraction based on the degree of kurtosis and in the presence of non-circular measurement noise. The existence and uniqueness analysis of the solution is followed by a study of fast converging variants of the algorithm. The performance is first assessed through simulations on well understood benchmark signals, followed by a case study on real-time artifact removal from EEG signals, verified using both qualitative and quantitative metrics. The results illustrate the power of the proposed approach in real-time blind extraction of general complex-valued sources.

  4. A Parametric Computational Study of the Impact of Non-circular Configurations on Bioprosthetic Heart Valve Leaflet Deformations and Stresses: Possible Implications for Transcatheter Heart Valves.

    PubMed

    Duraiswamy, Nandini; Weaver, Jason D; Ekrami, Yasamin; Retta, Stephen M; Wu, Changfu

    2016-06-01

    Although generally manufactured as circular devices with symmetric leaflets, transcatheter heart valves can become non-circular post-implantation, the impact of which on the long-term durability of the device is unclear. We investigated the effects of five non-circular (EllipMajor, EllipMinor, D-Shape, TriVertex, TriSides) annular configurations on valve leaflet stresses and valve leaflet deformations through finite element analysis. The highest in-plane principal stresses and strains were observed under an elliptical configuration with an aspect ratio of 1.25 where one of the commissures was on the minor axis of the ellipse. In this elliptical configuration (EllipMinor), the maximum principal stress increased 218% and the maximum principal strain increased 80% as compared with those in the circular configuration, and occurred along the free edge of the leaflet whose commissures were not on the minor axis (i.e., the "stretched" leaflet). The D-Shape configuration was similar to this elliptical configuration, with the degree to which the leaflets were stretched or sagging being less than the EllipMinor configuration. The TriVertex and TriSides configurations had similar leaflet deformation patterns in all three leaflets and similar to the Circular configuration. In the D-Shape, TriVertex, and TriSides configurations, the maximum principal stress was located near the commissures similar to the Circular configuration. In the EllipMinor and EllipMajor configurations, the maximum principal stress occurred near the center of the free edge of the "stretched" leaflets. These results further affirm recommendations by the International Standards Organization (ISO) that pre-clinical testing should consider non-circular configurations for transcatheter valve durability testing.

  5. Directed swimming of nanoscale swimmers in an array of posts with non-circular section: modelling and shape optimization

    NASA Astrophysics Data System (ADS)

    Tong, Jiajun; Shelley, Michael

    2016-11-01

    It has been shown experimentally that swimming of nanoscale rod-like bi-metallic swimmers can be biased and guided by an array of teardrop shaped posts in the solution, giving rise to a statistically directed motion in long time. This could be useful in many applications like concentrating nanoswimmers, or separating them from non-motile particles. We pose a model to study such directed swimming, taking into account the absorption and desorption of the swimmers to the vertical walls of posts. We emphasize the role of varying curvature along the circumference of a single post on the absorption and desorption. In seeking to enhance directed swimming, we apply shape optimization to find how we can design, based on experimental data, better posts which have higher efficiency of transporting swimmers. This work was partially supported by the National Science Foundation under Award Number DMS-1463962.

  6. The role of independent motion in object segmentation in the ventral visual stream: Learning to recognise the separate parts of the body.

    PubMed

    Higgins, I V; Stringer, S M

    2011-03-25

    This paper investigates how the visual areas of the brain may learn to segment the bodies of humans and other animals into separate parts. A neural network model of the ventral visual pathway, VisNet, was used to study this problem. In particular, the current work investigates whether independent motion of body parts can be sufficient to enable the visual system to learn separate representations of them even when the body parts are never seen in isolation. The network was shown to be able to separate out the independently moving body parts because the independent motion created statistical decoupling between them.

  7. Hartley 2 and Tempel 1 comet nuclei demonstrate shapes and structurizations revealing an action of inertia-gravity forces exited by non-circular orbits

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2011-10-01

    Recently obtained images of Hartley 2 and Tempe l 1 co mets ( NASA's EPOXI and NEXT missions) reveal unprecedented details of the comets shaping and structurizat ion helping understand making them forces. The wave planetology [1-6 & others ] long ago s tated that "orbits make s tructures '. This as s ertion was bas ed on recognition of ine rtiagravity forces aroused in any cosmic body because of its movement in non-circular keplerian orbit. Such an orbit implies periodically changing accelerations causing inertia-gravity forces absorbed by a cosmic body by its warping, undulations. These standing wave warpings in rotating bodies have four interfering ortho- and diagonal direct ions producing uplifted (+), subsided (-) and neutral compensated (0) tectonic blocks. The blocks sizes depend on warping wavelengths the longest and most amplitudinal of which is the fundamental wave 1 long 2πR. Thes e waves produce inevitable tectonic dichotomy - a body division in two opposite segments -hemispheres: one uplifted, another subsided (an example is Earth with its uplifted continental and subsided oceanic hemispheres). In small bodies with a weak gravity one often observes oblong convexoconcave shapes so typical for the Main Belt asteroids.

  8. The SAMI Galaxy Survey: gas streaming and dynamical M/L in rotationally supported systems

    NASA Astrophysics Data System (ADS)

    Cecil, G.; Fogarty, L. M. R.; Richards, S.; Bland-Hawthorn, J.; Lange, R.; Moffett, A.; Catinella, B.; Cortese, L.; Ho, I.-T.; Taylor, E. N.; Bryant, J. J.; Allen, J. T.; Sweet, S. M.; Croom, S. M.; Driver, S. P.; Goodwin, M.; Kelvin, L.; Green, A. W.; Konstantopoulos, I. S.; Owers, M. S.; Lawrence, J. S.; Lorente, N. P. F.

    2016-02-01

    Line-of-sight velocities of gas and stars can constrain dark matter (DM) within rotationally supported galaxies if they trace circular orbits extensively. Photometric asymmetries may signify non-circular motions, requiring spectra with dense spatial coverage. Our integral-field spectroscopy of 178 galaxies spanned the mass range of the Sydney-AAO Multi-object integral field spectrograph (SAMI) Galaxy Survey. We derived circular speed curves (CSCs) of gas and stars from non-parametric fits out to r ˜ 2re. For 12/14 with measured H I profiles, ionized gas and H I maximum velocities agreed. We fitted mass-follows-light models to 163 galaxies by approximating the radial light profile as nested, very flattened mass homeoids viewed as a Sérsic form. Fitting broad-band spectral energy distributions to Sloan Digital Sky Survey images gave median stellar mass/light 1.7 assuming a Kroupa initial mass function (IMF) versus 2.6 dynamically. Two-thirds of the dynamical mass/light measures were consistent with star+remnant IMFs. One-fifth required upscaled starlight to fit, hence comparable mass of unobserved baryons and/or DM distributed like starlight across the SAMI aperture that came to dominate motions as the starlight CSCs declined rapidly. The rest had mass distributed differently from light. Subtracting fits of Sérsic radial profiles to 13 VIKING Z-band images revealed residual weak bars. Near the bar major axis, we assessed m = 2 streaming velocities, and found deviations usually <30 km s-1 from the CSC; three showed no deviation. Thus, asymmetries rarely influenced the CSC despite colocated shock-indicating, emission-line flux ratios in more than 2/3 of our sample.

  9. Occluded motion alters event perception.

    PubMed

    Kawachi, Yousuke; Gyoba, Jiro

    2013-04-01

    We employed audiovisual stream/bounce displays, in which two moving objects with crossing trajectories are more likely to be perceived as bouncing off, rather than streaming through, each other when a brief sound is presented at the coincidence of the two objects. However, Kawachi and Gyoba (Perception 35:1289-1294, 2006b) reported that the presence of an additional moving object near the two objects altered the perception of a bouncing event to that of a streaming event. In this study, we extended this finding and examined whether alteration of the event perception could be induced by the visual context, such as by occluded object motion near the stream/bounce display. The results demonstrated that even when the sound was presented, the continuous occluded motion strongly biased observers' percepts toward the streaming percept during a short occlusion interval (approximately 100 ms). In contrast, when the continuous occluded motion was disrupted by introducing a spatiotemporal gap in the motion trajectory or by removing occlusion cues such as deletion/accretion, the bias toward the streaming percept declined. Thus, we suggest that a representation of object motion generated under a limited occlusion interval interferes with audiovisual event perception.

  10. Sparing of Sensitivity to Biological Motion but Not of Global Motion after Early Visual Deprivation

    ERIC Educational Resources Information Center

    Hadad, Bat-Sheva; Maurer, Daphne; Lewis, Terri L.

    2012-01-01

    Patients deprived of visual experience during infancy by dense bilateral congenital cataracts later show marked deficits in the perception of global motion (dorsal visual stream) and global form (ventral visual stream). We expected that they would also show marked deficits in sensitivity to biological motion, which is normally processed in the…

  11. Consider an Ice Stream.

    NASA Astrophysics Data System (ADS)

    Bindschadler, R.

    2002-12-01

    positions in past millennia conform to radically different flow patterns while on the scale of hours an ice stream's motion is halted completely, then released to move at surge-like speeds, in tempo with the tides. Explaining these complexities constantly reminds us that the rigorous physics applied to ice so effectively by Nye still work.

  12. Unsteady disturbances of streaming motions around bodies

    NASA Technical Reports Server (NTRS)

    Atassi, H. M.; Grzedzinski, J.

    1989-01-01

    The present investigation of flows around bodies with a stagnation point notes that the vortical part of such flows becomes singular along the entire body surface and its wake; as a result, the potential part of the flow will also be singular along the entire surface. A modified splitting of the velocity field is proposed which encompasses: (1) a vortical part having zero streamwise and normal components along the body surface; (2) an entropy-dependent part; and (3) a regular part similar to the potential part which satisfies a linear inhomogeneous wave equation with a modified source term.

  13. stream-stream: Stellar and dark-matter streams interactions

    NASA Astrophysics Data System (ADS)

    Bovy, Jo

    2017-02-01

    Stream-stream analyzes the interaction between a stellar stream and a disrupting dark-matter halo. It requires galpy (ascl:1411.008), NEMO (ascl:1010.051), and the usual common scientific Python packages.

  14. Generation of mock tidal streams

    NASA Astrophysics Data System (ADS)

    Fardal, Mark A.; Huang, Shuiyao; Weinberg, Martin D.

    2015-09-01

    In this paper, we discuss a method for the generation of mock tidal streams. Using an ensemble of simulations in an isochrone potential where the actions and frequencies are known, we derive an empirical recipe for the evolving satellite mass and the corresponding mass-loss rate, and the ejection conditions of the stream material. The resulting stream can then be quickly generated either with direct orbital integration, or by using the action-angle formalism. The model naturally produces streaky features within the stream. These are formed due to the radial oscillation of the progenitor and the bursts of stars emitted near pericentre, rather than clumping at particular oscillation phases as sometimes suggested. When detectable, these streaky features are a reliable diagnostic for the stream's direction of motion and encode other information on the progenitor and its orbit. We show several tests of the recipe in alternate potentials, including a case with a chaotic progenitor orbit which displays a marked effect on the width of the stream. Although the specific ejection recipe may need adjusting when elements such as the orbit or satellite density profile are changed significantly, our examples suggest that model tidal streams can be quickly and accurately generated by models of this general type for use in Bayesian sampling.

  15. Dynamical Properties of Collisionless Star Streams

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.

    2015-02-01

    A sufficiently extended satellite in the tidal field of a host galaxy loses mass to create nearly symmetric leading and trailing tidal streams. We study the case in which tidal heating drives mass loss from a low mass satellite. The stream effectively has two dynamical components, a common angular momentum core superposed with episodic pulses with a broader angular momentum distribution. The pulses appear as spurs on the stream, oscillating above and below the stream centerline, stretching and blurring in configuration space as they move away from the cluster. Low orbital eccentricity streams are smoother and have less differential motion than high eccentricity streams. The tail of a high eccentricity stream can develop a fan of particles that wraps around at apocenter in a shell feature. We show that scaling the essentially stationary action-angle variables with the cube root of the satellite mass allows a low mass satellite stream to accurately predict the features in the stream from a satellite a thousand times more massive. As a practical astrophysical application, we demonstrate that narrow gaps in a moderate eccentricity stream, such as GD-1, blur out to 50% contrast over approximately six radial periods. A high eccentricity stream, such as Pal 5, will blur small gaps in only two radial orbits as can be understood from the much larger dispersion of angular momentum in the stream.

  16. On feathers, bifurcations and shells: the dynamics of tidal streams across the mass scale

    NASA Astrophysics Data System (ADS)

    Amorisco, N. C.

    2015-06-01

    I present an organic description of the spectrum of regimes of collisionless tidal streams and define the orderings between the relevant physical quantities that shape their morphology. Three fundamental dichotomies are identified and described in the form of dimensionless inequalities. These govern (i) the speed of the stream's growth, (ii) the internal coherence of the stream and (iii) its thickness or opening angle, within and outside the orbital plane. The mechanisms through which such main qualitative properties are regulated and the relevant limiting cases are analysed. For example, the slope of the host's density profile strongly influences the speed of the stream's growth, in both length and width, as steeper density profiles enhance differential streaming. Internal coherence is the natural requirement for the appearance of substructure and overdensities in tidal debris, and I concentrate on the characteristic `feathering' typical of streams of star clusters. Overdensities and substructures are associated with minima in the relative streaming velocity of the stream members. For streams with high circularity, these are caused by the epicyclic oscillations of stars; however, for highly non-circular progenitor's orbits, internal substructure is caused by the oscillating differences in energy and actions with which material is shed at different orbital phases of the progenitor. This modulation results in different streaming speeds along the tidal arm: the streakline of material shed between two successive apocentric passages is folded along its length, pulled at its centre by the faster differential streaming of particles released near pericentre, which are therefore more widely scattered. When the stream is coherent enough, the same mechanism is potentially capable of generating a bimodal profile in the density distributions of the longer wraps of more massive progenitors, which I dub `bifurcations'. The conditions that allow streams to be internally coherent

  17. Steady streaming around a cylinder pair

    NASA Astrophysics Data System (ADS)

    Coenen, W.

    2016-11-01

    The steady streaming motion that appears around a pair of circular cylinders placed in a small-amplitude oscillatory flow is considered. Attention is focused on the case where the Stokes layer thickness at the surface of the cylinders is much smaller than the cylinder radius, and the streaming Reynolds number is of order unity or larger. In that case, the steady streaming velocity that persists at the edge of the Stokes layer can be imposed as a boundary condition to numerically solve the outer streaming motion that it drives in the bulk of the fluid. It is investigated how the gap width between the cylinders and the streaming Reynolds number affect the flow topology. The results are compared against experimental observations.

  18. Stream Studies.

    ERIC Educational Resources Information Center

    Hamilton City Board of Education (Ontario).

    This manual provides teachers with some knowledge of ecological study methods and techniques used in collecting data when plants and animals are studied in the field. Most activities deal with the interrelatedness of plant and animal life to the structure and characteristics of a stream and pond. Also included in this unit plan designed for the…

  19. Thermal control of ice-stream margins

    NASA Technical Reports Server (NTRS)

    Raymond, Charles F.

    1993-01-01

    The thermal balance at the base of an ice sheet near an ice-stream margin was investigated theoretically. Specifically, conditions such that the base of the ice sheet would be frozen in the absence of heat generated by the ice motion were investigated. The base of the ice stream is maintained at melting as a result of high dissipation of heat at the base associated with its fast motion over the bed. Heat dissipation in the inter-ice-stream ridge ice is presumed to be too small to maintain melting conditions on the bed there. Two opposing effects can be identified near the shear margin separating the fast and slow motions. Because the velocity of an ice stream falls off toward its margin, there is a near margin heat deficit zone where the heat generated at the bed is not, by itself, sufficient to maintain melting conditions. Without some counteracting process, the base could freeze inward toward the ice stream and cause it to narrow. The marginal shearing generates heat within the ice above the bed. This heat produces a thermal shielding effect that tends to warm the bed on both sides of the boundary between the fast and slow motion. This shielding effect, if strong enough, could produce a thawed zone beyond the fast/slow boundary. If melting at the bed by itself allows fast motion, then the ice stream would be free to widen. A coupled mass and heat flow model is being developed to examine these competing processes. Preliminary calculations using available information for boundary conditions appropriate for Ice Stream B predict that the shielding effect is most important. This tentative result suggests that thermal conditions are such that the ice stream could widen unstably. Other constraints would be required to stabilize the width. Possible factors could be bed morphology beneath ridges that does not allow fast motion even in thawed conditions, or inward advection of cold ice from the ridges across the margin and into the ice stream, which suppresses the

  20. Two-character motion analysis and synthesis.

    PubMed

    Kwon, Taesoo; Cho, Young-Sang; Park, Sang Il; Shin, Sung Yong

    2008-01-01

    In this paper, we deal with the problem of synthesizing novel motions of standing-up martial arts such as Kickboxing, Karate, and Taekwondo performed by a pair of human-like characters while reflecting their interactions. Adopting an example-based paradigm, we address three non-trivial issues embedded in this problem: motion modeling, interaction modeling, and motion synthesis. For the first issue, we present a semi-automatic motion labeling scheme based on force-based motion segmentation and learning-based action classification. We also construct a pair of motion transition graphs each of which represents an individual motion stream. For the second issue, we propose a scheme for capturing the interactions between two players. A dynamic Bayesian network is adopted to build a motion transition model on top of the coupled motion transition graph that is constructed from an example motion stream. For the last issue, we provide a scheme for synthesizing a novel sequence of coupled motions, guided by the motion transition model. Although the focus of the present work is on martial arts, we believe that the framework of the proposed approach can be conveyed to other two-player motions as well.

  1. Plate motion

    SciTech Connect

    Gordon, R.G. )

    1991-01-01

    The motion of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global model of current plate motions, diffuse plate boundaries and the oceanic lithosphere, the relation between plate motions and distributed deformations, accelerations and the steadiness of plate motions, the distribution of current Pacific-North America motion across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.

  2. Feature integration and object representations along the dorsal stream visual hierarchy

    PubMed Central

    Perry, Carolyn Jeane; Fallah, Mazyar

    2014-01-01

    The visual system is split into two processing streams: a ventral stream that receives color and form information and a dorsal stream that receives motion information. Each stream processes that information hierarchically, with each stage building upon the previous. In the ventral stream this leads to the formation of object representations that ultimately allow for object recognition regardless of changes in the surrounding environment. In the dorsal stream, this hierarchical processing has classically been thought to lead to the computation of complex motion in three dimensions. However, there is evidence to suggest that there is integration of both dorsal and ventral stream information into motion computation processes, giving rise to intermediate object representations, which facilitate object selection and decision making mechanisms in the dorsal stream. First we review the hierarchical processing of motion along the dorsal stream and the building up of object representations along the ventral stream. Then we discuss recent work on the integration of ventral and dorsal stream features that lead to intermediate object representations in the dorsal stream. Finally we propose a framework describing how and at what stage different features are integrated into dorsal visual stream object representations. Determining the integration of features along the dorsal stream is necessary to understand not only how the dorsal stream builds up an object representation but also which computations are performed on object representations instead of local features. PMID:25140147

  3. Evidence for the Magellanic Stream's Tidal Origin

    NASA Astrophysics Data System (ADS)

    Putman, Mary E.; Gibson, Brad K.; Staveley-Smith, Lister

    The complete spatial coverage and unique blind nature of the HI Parkes All-Sky Survey (HIPASS) has allowed us to identify new HI features which have implications for the origin of the Magellanic Stream. The data presented here include a 2400 deg^2 mosaic of the HI distribution about the South Celestial Pole, revealing a counter-stream which leads the direction of motion of the Clouds, i.e. opposite in direction to the Stream. This strongly supports the gravitational model for the Stream in which the leading and trailing streams are tidally torn from the body of the Magellanic Clouds. This Leading Arm, as well as other recent results which support a tidal scenario, will be discussed.

  4. Brownian motion

    NASA Astrophysics Data System (ADS)

    Lavenda, B. H.

    1985-02-01

    Brownian motion, the doubly random motion of small particles suspended in a liquid due to molecular collisions, and its implications and applications in the history of modern science are discussed. Topics examined include probabilistic phenomena, the kinetic theory of gases, Einstein's atomic theory of Brownian motion, particle displacement, diffusion measurements, the determination of the mass of the atom and of Avogadro's number, the statistical mechanics of thermodynamics, nonequilibrium systems, Langevin's equation of motion, time-reversed evolution, mathematical analogies, and applications in economics and radio navigation. Diagrams and drawings are provided.

  5. Non-Circular Wheels: Reuleaux and Squares

    ERIC Educational Resources Information Center

    Mills, Allan

    2011-01-01

    Circular wheels are so familiar on vehicles of all types that it is seldom realized that alternatives do exist. This short non-mathematical article describes Reuleaux and square wheels that, rolling along appropriate tracks, can maintain a moving platform at a constant height. Easily made working models lend themselves to demonstrations at science…

  6. Basal melt beneath whillans ice stream and ice streams A and C

    NASA Technical Reports Server (NTRS)

    Joughin, I.; Teluezyk, S.; Engelhardt, H.

    2002-01-01

    We have used a recently derived map of the velocity of Whillans Ice Stream and Ice Streams A and C to help estimate basal melt. Temperature was modeled with a simple vertical advection-diffusion equation, 'tuned' to match temperature profiles. We find that most of the melt occurs beneath the tributaries where larger basal shear stresses and thicker ice favors greater melt (e.g., 10-20 mm/yr). The occurrence of basal freezing is predicted beneath much of the ice plains of Ice Stream C and Whillans Ice Stream. Modelled melt rates for when Ice Stream C was active suggest there was just enough melt water generated in its tributaries to balance basal freezing on its ice plain. Net basal melt for Whillans Ice Stream is positive due to smaller basal temperature gradients. Modelled temperatures on Whillans Ice Stream, however, were constrained by a single temperature profile at UpB. Basal temperature gradients for Whillans B1 and Ice Stream A may have conditions more similar to those beneath Ice Streams C and D, in which case, there may not be sufficient melt to sustain motion. This would be consistent with the steady deceleration of Whillans stream over the last few decades.

  7. Integration and segregation in auditory streaming

    NASA Astrophysics Data System (ADS)

    Almonte, Felix; Jirsa, Viktor K.; Large, Edward W.; Tuller, Betty

    2005-12-01

    We aim to capture the perceptual dynamics of auditory streaming using a neurally inspired model of auditory processing. Traditional approaches view streaming as a competition of streams, realized within a tonotopically organized neural network. In contrast, we view streaming to be a dynamic integration process which resides at locations other than the sensory specific neural subsystems. This process finds its realization in the synchronization of neural ensembles or in the existence of informational convergence zones. Our approach uses two interacting dynamical systems, in which the first system responds to incoming acoustic stimuli and transforms them into a spatiotemporal neural field dynamics. The second system is a classification system coupled to the neural field and evolves to a stationary state. These states are identified with a single perceptual stream or multiple streams. Several results in human perception are modelled including temporal coherence and fission boundaries [L.P.A.S. van Noorden, Temporal coherence in the perception of tone sequences, Ph.D. Thesis, Eindhoven University of Technology, The Netherlands, 1975], and crossing of motions [A.S. Bregman, Auditory Scene Analysis: The Perceptual Organization of Sound, MIT Press, 1990]. Our model predicts phenomena such as the existence of two streams with the same pitch, which cannot be explained by the traditional stream competition models. An experimental study is performed to provide proof of existence of this phenomenon. The model elucidates possible mechanisms that may underlie perceptual phenomena.

  8. Circular Motion.

    ERIC Educational Resources Information Center

    Lee, Paul D.

    1995-01-01

    Provides a period-long activity using battery powered cars rolling in a circular motion on a tile floor. Students measure the time and distance as the car moves to derive the equation for centripetal acceleration. (MVL)

  9. Predicting Early Reading Skills from Pre-Reading Measures of Dorsal Stream Functioning

    ERIC Educational Resources Information Center

    Kevan, Alison; Pammer, Kristen

    2009-01-01

    It is well documented that good reading skills may be dependent upon adequate dorsal stream processing. However, the degree to which dorsal stream deficits play a causal role in reading failure has not been established. This study used coherent motion and visual frequency doubling to examine whether dorsal stream sensitivity measured before the…

  10. Simulation of dust streaming in toroidal traps: Stationary flows

    SciTech Connect

    Reichstein, Torben; Piel, Alexander

    2011-08-15

    Molecular-dynamic simulations were performed to study dust motion in a toroidal trap under the influence of the ion drag force driven by a Hall motion of the ions in E x B direction, gravity, inter-particle forces, and friction with the neutral gas. This article is focused on the inhomogeneous stationary streaming motion. Depending on the strength of friction, the spontaneous formation of a stationary shock or a spatial bifurcation into a fast flow and a slow vortex flow is observed. In the quiescent streaming region, the particle flow features a shell structure which undergoes a structural phase transition along the flow direction.

  11. Cortical dynamics of visual motion perception: short-range and long-range apparent motion.

    PubMed

    Grossberg, S; Rudd, M E

    1992-01-01

    This article describes further evidence for a new neural network theory of biological motion perception. The theory clarifies why parallel streams V1----V2, V1----MT, and V1----V2----MT exist for static form and motion form processing among the areas V1, V2, and MT of visual cortex. The theory suggests that the static form system (Static BCS) generates emergent boundary segmentations whose outputs are insensitive to direction-of-contrast and to direction-of-motion, whereas the motion form system (Motion BCS) generates emergent boundary segmentations whose outputs are insensitive to direction-of-contrast but sensitive to direction-of-motion. The theory is used to explain classical and recent data about short-range and long-range apparent motion percepts that have not yet been explained by alternative models. These data include beta motion, split motion, gamma motion and reverse-contrast gamma motion, delta motion, and visual inertia. Also included are the transition from group motion to element motion in response to a Ternus display as the interstimulus interval (ISI) decreases; group motion in response to a reverse-contrast Ternus display even at short ISIs; speed-up of motion velocity as interflash distance increases or flash duration decreases; dependence of the transition from element motion to group motion on stimulus duration and size, various classical dependencies between flash duration, spatial separation, ISI, and motion threshold known as Korte's laws; dependence of motion strength on stimulus orientation and spatial frequency; short-range and long-range form-color interactions; and binocular interactions of flashes to different eyes.

  12. Inventory of miscellaneous streams

    SciTech Connect

    Haggard, R.D.

    1998-08-14

    Miscellaneous streams discharging to the soil column on the Hanford Site are subject to requirements of several milestones identified in Consent Order No. DE 9INM-177 (Ecology and DOE 1991). The Plan and Schedule for Disposition and Regulatory Compliance for Miscellaneous Stream (DOE/RL-93-94) provides a plan and schedule for the disposition of miscellaneous streams to satisfy one of the Section 6.0 requirements of the Consent Order. One of the commitments (Activity 6-2.2) established in the plan and schedule is to annually update, the miscellaneous streams inventory. This document constitutes the 1998 revision of the miscellaneous streams inventory. Miscellaneous stream discharges were grouped into four permitting categories (Table 1). The first miscellaneous streams Permit (ST 4508) was issued May 30, 1997, to cover wastewater discharges from hydrotesting, maintenance, and construction activities. The second miscellaneous streams Permit (ST4509) covers discharges from cooling water and condensate discharges. The third permit application for category three waste streams was eliminated by recategorizing waste streams into an existing miscellaneous streams permit or eliminating stream discharges. Elimination of the third categorical permit application was approved by Ecology in January 1997 (Ecology 1997). The fourth permit application, to cover storm water, is due to Ecology in September 1998. Table 1 provides a history of the miscellaneous streams permitting activities.

  13. Tributaries of West Antarctic Ice Streams Revealed by RADARSAT Interferometry.

    PubMed

    Joughin; Gray; Bindschadler; Price; Morse; Hulbe; Mattar; Werner

    1999-10-08

    Interferometric RADARSAT data are used to map ice motion in the source areas of four West Antarctic ice streams. The data reveal that tributaries, coincident with subglacial valleys, provide a spatially extensive transition between slow inland flow and rapid ice stream flow and that adjacent ice streams draw from shared source regions. Two tributaries flow into the stagnant ice stream C, creating an extensive region that is thickening at an average rate of 0.49 meters per year. This is one of the largest rates of thickening ever reported in Antarctica.

  14. Two-stream instability with time-dependent drift velocity

    DOE PAGES

    Qin, Hong; Davidson, Ronald C.

    2014-06-26

    The classical two-stream instability driven by a constant relative drift velocity between two plasma components is extended to the case with time-dependent drift velocity. A solution method is developed to rigorously define and calculate the instability growth rate for linear perturbations relative to the time-dependent unperturbed two-stream motions. The stability diagrams for the oscillating two-stream instability are presented over a large region of parameter space. It is shown that the growth rate for the classical two-stream instability can be significantly reduced by adding an oscillatory component to the relative drift velocity.

  15. Brownian Motion.

    ERIC Educational Resources Information Center

    Lavenda, Bernard H.

    1985-01-01

    Explains the phenomenon of Brownian motion, which serves as a mathematical model for random processes. Topics addressed include kinetic theory, Einstein's theory, particle displacement, and others. Points out that observations of the random course of a particle suspended in fluid led to the first accurate measurement of atomic mass. (DH)

  16. Motion Sickness

    MedlinePlus

    ... but it is more common in children, pregnant women, and people taking certain medicines. Motion sickness can start suddenly, with a queasy feeling and cold sweats. It can then lead to dizziness and nausea and vomiting. Your brain senses movement by getting signals from your inner ears, eyes, ...

  17. Regex-Stream

    SciTech Connect

    Goodall, John

    2012-09-01

    Log files are typically semi-or un-structured. To be useable, they need to be parsed into a standard, structured format. Regex-Stream facilitates parsing text files into structured data (JSON) in streams of data.

  18. Prioritized Contact Transport Stream

    NASA Technical Reports Server (NTRS)

    Hunt, Walter Lee, Jr. (Inventor)

    2015-01-01

    A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

  19. Interplanetary stream magnetism - Kinematic effects

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Barouch, E.

    1976-01-01

    The particle density and the magnetic-field intensity and direction are calculated for volume elements of the solar wind as a function of the initial magnetic-field direction and the initial speed gradient. It is assumed that the velocity is constant and radial. These assumptions are approximately valid between about 0.1 and 1.0 AU for many streams. Time profiles of the particle density, field intensity, and velocity are calculated for corotating streams, neglecting effects of pressure gradients. The compression and rarefaction of the magnetic field depend sensitively on the initial field direction. By averaging over a typical stream, it is found that the average radial field intensity is inversely proportional to the square of the heliocentric distance, whereas the average intensity in the direction of the planets' motion does not vary in a simple way, consistent with deep space observations. Changes of field direction may be very large, depending on the initial angle; but when the initial angle at 0.1 AU is such that the base of the field line corotates with the sun, the spiral angle is the preferred direction at 1 AU. The theory is also applicable to nonstationary flows.

  20. Coherent Motion Sensitivity Predicts Individual Differences in Subtraction

    ERIC Educational Resources Information Center

    Boets, Bart; De Smedt, Bert; Ghesquiere, Pol

    2011-01-01

    Recent findings suggest deficits in coherent motion sensitivity, an index of visual dorsal stream functioning, in children with poor mathematical skills or dyscalculia, a specific learning disability in mathematics. We extended these data using a longitudinal design to unravel whether visual dorsal stream functioning is able to "predict"…

  1. Effects of self-motion on auditory scene analysis.

    PubMed

    Kondo, Hirohito M; Pressnitzer, Daniel; Toshima, Iwaki; Kashino, Makio

    2012-04-24

    Auditory scene analysis requires the listener to parse the incoming flow of acoustic information into perceptual "streams," such as sentences from a single talker in the midst of background noise. Behavioral and neural data show that the formation of streams is not instantaneous; rather, streaming builds up over time and can be reset by sudden changes in the acoustics of the scene. Here, we investigated the effect of changes induced by voluntary head motion on streaming. We used a telepresence robot in a virtual reality setup to disentangle all potential consequences of head motion: changes in acoustic cues at the ears, changes in apparent source location, and changes in motor or attentional processes. The results showed that self-motion influenced streaming in at least two ways. Right after the onset of movement, self-motion always induced some resetting of perceptual organization to one stream, even when the acoustic scene itself had not changed. Then, after the motion, the prevalent organization was rapidly biased by the binaural cues discovered through motion. Auditory scene analysis thus appears to be a dynamic process that is affected by the active sensing of the environment.

  2. [Motion sickness].

    PubMed

    Taillemite, J P; Devaulx, P; Bousquet, F

    1997-01-01

    Motion sickness is a general term covering sea-sickness, car-sickness, air-sickness, and space-sickness. Symptoms can occur when a person is exposed to unfamiliar movement whether real or simulated. Despite progress in the technology and comfort of modern transportation (planes, boats, and overland vehicles), a great number of travelers still experience motion sickness. Bouts are characterized by an initial phase of mild discomfort followed by neurologic and gastro-intestinal manifestations. The delay in onset depends on specific circumstances and individual susceptibility. Attacks are precipitated by conflicting sensory, visual, and vestibular signals but the underlying mechanism is unclear. Most medications used for prevention and treatment (e.g. anticholinergics and antihistamines) induce unwanted sedation. Furthermore no one drug is completely effective or preventive under all conditions.

  3. The dorsal visual stream revisited: Stable circuits or dynamic pathways?

    PubMed

    Galletti, Claudio; Fattori, Patrizia

    2017-01-23

    In both macaque and human brain, information regarding visual motion flows from the extrastriate area V6 along two different paths: a dorsolateral one towards areas MT/V5, MST, V3A, and a dorsomedial one towards the visuomotor areas of the superior parietal lobule (V6A, MIP, VIP). The dorsolateral visual stream is involved in many aspects of visual motion analysis, including the recognition of object motion and self motion. The dorsomedial stream uses visual motion information to continuously monitor the spatial location of objects while we are looking and/or moving around, to allow skilled reaching for and grasping of the objects in structured, dynamically changing environments. Grasping activity is present in two areas of the dorsal stream, AIP and V6A. Area AIP is more involved than V6A in object recognition, V6A in encoding vision for action. We suggest that V6A is involved in the fast control of prehension and plays a critical role in biomechanically selecting appropriate postures during reach to grasp behaviors. In everyday life, numerous functional networks, often involving the same cortical areas, are continuously in action in the dorsal visual stream, with each network dynamically activated or inhibited according to the context. The dorsolateral and dorsomedial streams represent only two examples of these networks. Many others streams have been described in the literature, but it is worthwhile noting that the same cortical area, and even the same neurons within an area, are not specific for just one functional property, being part of networks that encode multiple functional aspects. Our proposal is to conceive the cortical streams not as fixed series of interconnected cortical areas in which each area belongs univocally to one stream and is strictly involved in only one function, but as interconnected neuronal networks, often involving the same neurons, that are involved in a number of functional processes and whose activation changes dynamically according

  4. Persistent Temporal Streams

    NASA Astrophysics Data System (ADS)

    Hilley, David; Ramachandran, Umakishore

    Distributed continuous live stream analysis applications are increasingly common. Video-based surveillance, emergency response, disaster recovery, and critical infrastructure protection are all examples of such applications. They are characterized by a variety of high- and low-bandwidth streams as well as a need for analyzing both live and archived streams. We present a system called Persistent Temporal Streams (PTS) that supports a higher-level, domain-targeted programming abstraction for such applications. PTS provides a simple but expressive stream abstraction encompassing transport, manipulation and storage of streaming data. In this paper, we present a system architecture for implementing PTS. We provide an experimental evaluation which shows the system-level primitives can be implemented in a lightweight and high-performance manner, and an application-based evaluation designed to show that a representative high-bandwidth stream analysis application can be implemented relatively simply and with good performance.

  5. The Magellanic Stream: Circumnavigating the Galaxy

    NASA Astrophysics Data System (ADS)

    D'Onghia, Elena; Fox, Andrew J.

    2016-09-01

    The Magellanic Clouds are surrounded by an extended network of gaseous structures. Chief among these is the Magellanic Stream, an interwoven tail of filaments trailing the Clouds in their orbit around the Milky Way. When considered in tandem with its Leading Arm, the Stream stretches over 200° on the sky. The Stream is thought to represent the result of tidal interactions between the Clouds and ram-pressure forces exerted by the Galactic corona, and its kinematic properties reflect the dynamical history of the pair of dwarf galaxies closest to the Milky Way. The Stream is a benchmark for hydrodynamical simulations of accreting gas and cloud/corona interactions. If the Stream survives these interactions and arrives safely in the Galactic disk, its cargo of over a billion solar masses of gas has the potential to maintain or elevate the Galactic star-formation rate. In this article, we review the current state of knowledge of the Stream, including its chemical composition, physical conditions, origin, and fate. We also review the dynamics of the Magellanic System, including the proper motions and orbital history of the Large and Small Magellanic Clouds, the first-passage and second-passage scenarios, and the evidence for a Magellanic Group of galaxies.

  6. The psychophysics of Visual Motion and Global form Processing in Autism

    ERIC Educational Resources Information Center

    Koldewyn, Kami; Whitney, David; Rivera, Susan M.

    2010-01-01

    Several groups have recently reported that people with autism may suffer from a deficit in visual motion processing and proposed that these deficits may be related to a general dorsal stream dysfunction. In order to test the dorsal stream deficit hypothesis, we investigated coherent and biological motion perception as well as coherent form…

  7. Effect of vertical motion on current meters

    USGS Publications Warehouse

    Kallio, Nicholas A.

    1966-01-01

    The effect of vertical motion on the performance of current meters at various stream velocities was evaluated to determine whether accurate discharge measurements can be made from a bobbing boat. Three types of current meters--Ott, Price, and vane types--were tested under conditions simulating a bobbing boat. A known frequency and amplitude of vertical motion were imparted to the current meter, and the related effect on the measured stream velocity was determined. One test of the Price meter was made under actual conditions, using a boat and standard measuring gear. The results of the test under actual conditions verified those obtained by simulating the vertical movements of a boat. The tests show that for stream velocities below 2.5 feet per second the accuracy of all three meters is significantly affected when the meters are subjected to certain conditions of vertical motion that can occur during actual field operations. Both the rate of vertical motion and the frequency of vertical oscillation affect the registration of the meter. The results of these tests, presented in the form of graphs and tables, can be used as a guide to determine whether wind and stream flow are within an acceptable range for a reliable discharge measurement from a boat.

  8. Observations of ion streaming during substorms

    NASA Technical Reports Server (NTRS)

    Lui, A. T. Y.; Williams, D. J.; Eastman, T. E.; Frank, L. A.

    1983-01-01

    The ion beam phenomenon at the plasma sheet boundary is examined for individually identifiable substorms, and the substorm-associated particle phenomena are evaluated in terms of the energy-angle distributions of the plasma population and three-dimensional energetic ion distributions. In all seven cases studied it is found that ion beams streaming earthward and/or tailward are always present at the edge of the plasma sheet adjacent to the tail lobe. Ion beams penetrating into the plasma sheet region with no detectable density gradient are also observed. Beams at tens to hundreds of eV often stream tailward and are often long lasting, suggesting that they may be related to ionospheric sources. Both tailward and earthward streaming beams are detected for ion beams above 1 keV, consistent with an origin from the distant tail, propagation toward earth, and mirroring back under single particle motions.

  9. Cortical Locus of Coherent Motion Deficits in Deaf Poor Readers

    ERIC Educational Resources Information Center

    Samar, Vincent J.; Parasnis, Ila

    2007-01-01

    Samar and Parasnis [Samar, V. J., & Parasnis, I. (2005). Dorsal stream deficits suggest hidden dyslexia among deaf poor readers: correlated evidence from reduced perceptual speed and elevated coherent motion detection thresholds. "Brain and Cognition, 58," 300-311.] reported that correlated measures of coherent motion detection and perceptual…

  10. The Puzzling Ophiuchus Stream

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Dwarf galaxies or globular clusters orbiting the Milky Way can be pulled apart by tidal forces, leaving behind a trail of stars known as a stellar stream. One such trail, the Ophiuchus stream, has posed a serious dynamical puzzle since its discovery. But a recent study has identified four stars that might help resolve this streams mystery.Conflicting TimescalesThe stellar stream Ophiuchus was discovered around our galaxy in 2014. Based on its length, which appears to be 1.6 kpc, we can calculate the time that has passed since its progenitor was disrupted and the stream was created: ~250 Myr. But the stars within it are ~12 Gyr old, and the stream orbits the galaxy with a period of ~350 Myr.Given these numbers, we can assume that Ophiuchuss progenitor completed many orbits of the Milky Way in its lifetime. So why would it only have been disrupted 250 million years ago?Fanning StreamLed by Branimir Sesar (Max Planck Institute for Astronomy), a team of scientists has proposed an idea that might help solve this puzzle. If the Ophiuchus stellar stream is on a chaotic orbit common in triaxial potentials, which the Milky Ways may be then the stream ends can fan out, with stars spreading in position and velocity.The fanned part of the stream, however, would be difficult to detect because of its low surface brightness. As a result, the Ophiuchus stellar stream could actually be longer than originally measured, implying that it was disrupted longer ago than was believed.Search for Fan StarsTo test this idea, Sesar and collaborators performed a search around the ends of the stream, looking for stars thatare of the right type to match the stream,are at the predicted distance of the stream,are located near the stream ends, andhave velocities that match the stream and dont match the background halo stars.Histogram of the heliocentric velocities of the 43 target stars. Six stars have velocities matching the stream velocity. Two of these are located in the main stream; the other

  11. Gas stream purifier

    NASA Technical Reports Server (NTRS)

    Adam, Steven J.

    1994-01-01

    A gas stream purifier has been developed that is capable of removing corrosive acid, base, solvent, organic, inorganic, and water vapors as well as particulates from an inert mixed gas stream using only solid scrubbing agents. This small, lightweight purifier has demonstrated the ability to remove contaminants from an inert gas stream with a greater than 99 percent removal efficiency. The Gas Stream Purifier has outstanding market and sales potential in manufacturing, laboratory and science industries, medical, automotive, or any commercial industry where pollution, contamination, or gas stream purification is a concern. The purifier was developed under NASA contract NAS9-18200 Schedule A for use in the international Space Station. A patent application for the Gas Stream Purifier is currently on file with the United States Patent and Trademark Office.

  12. Inventory of miscellaneous streams

    SciTech Connect

    Lueck, K.J.

    1995-09-01

    On December 23, 1991, the US Department of Energy, Richland Operations Office (RL) and the Washington State Department of Ecology (Ecology) agreed to adhere to the provisions of the Department of Ecology Consent Order. The Consent Order lists the regulatory milestones for liquid effluent streams at the Hanford Site to comply with the permitting requirements of Washington Administrative Code. The RL provided the US Congress a Plan and Schedule to discontinue disposal of contaminated liquid effluent into the soil column on the Hanford Site. The plan and schedule document contained a strategy for the implementation of alternative treatment and disposal systems. This strategy included prioritizing the streams into two phases. The Phase 1 streams were considered to be higher priority than the Phase 2 streams. The actions recommended for the Phase 1 and 2 streams in the two reports were incorporated in the Hanford Federal Facility Agreement and Consent Order. Miscellaneous Streams are those liquid effluents streams identified within the Consent Order that are discharged to the ground but are not categorized as Phase 1 or Phase 2 Streams. This document consists of an inventory of the liquid effluent streams being discharged into the Hanford soil column.

  13. User aware video streaming

    NASA Astrophysics Data System (ADS)

    Kerofsky, Louis; Jagannath, Abhijith; Reznik, Yuriy

    2015-03-01

    We describe the design of a video streaming system using adaptation to viewing conditions to reduce the bitrate needed for delivery of video content. A visual model is used to determine sufficient resolution needed under various viewing conditions. Sensors on a mobile device estimate properties of the viewing conditions, particularly the distance to the viewer. We leverage the framework of existing adaptive bitrate streaming systems such as HLS, Smooth Streaming or MPEG-DASH. The client rate selection logic is modified to include a sufficient resolution computed using the visual model and the estimated viewing conditions. Our experiments demonstrate significant bitrate savings compare to conventional streaming methods which do not exploit viewing conditions.

  14. SAGITTARIUS STREAM THREE-DIMENSIONAL KINEMATICS FROM SLOAN DIGITAL SKY SURVEY STRIPE 82

    SciTech Connect

    Koposov, Sergey E.; Belokurov, Vasily; Evans, N. Wyn

    2013-04-01

    Using multi-epoch observations of the Stripe 82 region from the Sloan Digital Sky Survey (SDSS), we measure precise statistical proper motions of the stars in the Sagittarius (Sgr) stellar stream. The multi-band photometry and SDSS radial velocities allow us to efficiently select Sgr members and thus enhance the proper-motion precision to {approx}0.1 mas yr{sup -1}. We measure separately the proper motion of a photometrically selected sample of the main-sequence turn-off stars, as well as spectroscopically selected Sgr giants. The data allow us to determine the proper motion separately for the two Sgr streams in the south found in Koposov et al. Together with the precise velocities from SDSS, our proper motions provide exquisite constraints of the three-dimensional motions of the stars in the Sgr streams.

  15. Motion Simulator

    NASA Technical Reports Server (NTRS)

    1993-01-01

    MOOG, Inc. supplies hydraulic actuators for the Space Shuttle. When MOOG learned NASA was interested in electric actuators for possible future use, the company designed them with assistance from Marshall Space Flight Center. They also decided to pursue the system's commercial potential. This led to partnership with InterActive Simulation, Inc. for production of cabin flight simulators for museums, expositions, etc. The resulting products, the Magic Motion Simulator 30 Series, are the first electric powered simulators. Movements are computer-guided, including free fall to heighten the sense of moving through space. A projection system provides visual effects, and the 11 speakers of a digital laser based sound system add to the realism. The electric actuators are easier to install, have lower operating costs, noise, heat and staff requirements. The U.S. Space & Rocket Center and several other organizations have purchased the simulators.

  16. Evolution of the Quadrantid meteor stream

    NASA Technical Reports Server (NTRS)

    Jones, James; Jones, William

    1992-01-01

    According to previous orbital calculations, the last close approach of the Quadrantid stream with Jupiter occurred 3200 years ago at which time the parent comet of the stream may have been captured into its present short-period orbit. If this is the case the stream may only be a few thousand years old. We have modeled the evolution of the stream to determine if such a short time scale is consistent with the observed features of the Quadrantid/ delta- Aquarid/Arietid/Ursid complex. A detailed modeling of a stream consisting of 500 test particles released 4000 yr ago and which included the effects of the gravitational perturbations of 6 planets as well as the likely spread in the initial orbital elements resulting from the ejection of the grains from the comet was carried out. Our calculations indicate that an intense shower should be seen a few days before the Quadrantid shower, and that, 4000 yr is too short a period for the branch corresponding to the D-Arietid branch to appear. We have considered the quasi-constants of motion 1/a and J, the Tisserand quantity, and find that the Ursids and the D-Arietids are unlikely to be members of the complex, and that, the complex is probably be less than 4000 yr old.

  17. Three-body resonance in meteoroid streams

    NASA Astrophysics Data System (ADS)

    Sekhar, A.; Asher, D. J.; Vaubaillon, J.

    2016-08-01

    Mean-motion resonances play an important role in the evolution of various meteoroid streams. Previous works have studied the effects of two-body resonances in different comets and streams. These already established two-body resonances were mainly induced either by Jovian or Saturnian effects but not both at the same time. Some of these resonances have led to spectacular meteor outbursts and storms in the past. In this work, we find a new resonance mechanism involving three bodies - i.e. meteoroid particle, Jupiter and Saturn, in the Perseid meteoroid stream. Long-term three-body resonances are not very common in real small bodies in our Solar system although they can mathematically exist at many resonant sweet spots in an abstract sense in any dynamical system. This particular resonance combination in the Perseid stream is such that it is close to the ratio of 1:4:10 if the orbital periods of Perseid particle, Saturn and Jupiter are considered, respectively. These resonant Perseid meteoroids stay resonant for typically about 2 kyr. Highly compact dust trails due to this unique resonance phenomenon are present in our simulations. Some past and future years are presented where three-body resonant meteoroids of different sizes (or subject to different radiation pressures) are computed to come near the Earth. This is the first theoretical example of an active and stable three-body resonance mechanism in the realm of meteoroid streams.

  18. Citrus waste stream utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Waste streams, generated during fruit processing, consist of solid fruit residues in addition to liquid waste streams from washing operations which must be handled in an environmentally acceptable manner. Unsound fruit from packing houses are usually sent off to be processed for juice and the solid ...

  19. Adopt a Stream.

    ERIC Educational Resources Information Center

    Friends of Environmental Education Society of Alberta (Edmonton).

    This environmental education program is designed to increase awareness among junior high school students of stream ecosystems and those habitats which comprise the ecosystems adjacent to streams. The teaching content of the manual is presented in two major sections. The first section provides information and background material for the group…

  20. WADEABLE STREAMS ASSESSMENT

    EPA Science Inventory

    This Wadeable Streams Assessment (WSA) provides the first statistically defensible summary of the condition of the nation’s streams and small rivers, which are so integrally tied to our history. This report brings the results of this ground-breaking study to the American public....

  1. Auditory Motion Elicits a Visual Motion Aftereffect

    PubMed Central

    Berger, Christopher C.; Ehrsson, H. Henrik

    2016-01-01

    The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates. PMID:27994538

  2. Mass streams for spacecraft propulsion and energy generation

    SciTech Connect

    Hammer, J H

    2005-08-31

    A speculative propulsion concept is presented, based on accelerating a spacecraft by impact of a stream of matter in relative motion with respect to the spacecraft. To accelerate the stream to the needed velocity the stream mass is contained in a transit vehicle, launched at low velocity and hence low energy cost, and then sent on a trajectory with near encounters of the planets for gravitational assist. The mass arrives at Earth or wherever the propellant is needed at much higher velocity and kinetic energy, where it is released into an extended stream suitable for propulsion. The stream, moving at a relative velocity in the range of 10 to 30km/s, should be capable of both high thrust and high specific impulse. Means of limiting the transverse expansion of the stream during release and for the {approx}1000 seconds duration of impact are a critical requirement for practicality of the concept. The scheme could potentially lead to a virtually unlimited energy source. One can imagine using a portion of one stream to launch another, larger payload on a similar trajectory. This creates, in effect, an energy amplifier extracting energy from the orbital motions of the planets. The gain of the energy amplifier is only limited by the capacity to prepare mass in transit vehicles.

  3. Modeling ice streams: Derived quantities

    NASA Technical Reports Server (NTRS)

    Fastook, James

    1993-01-01

    The model addressed is a finite-element, map-plane, time-dependent, column-averaged continuity equation solver. The key to the fitting process involves the balance between ice motion dominated by flow in internal layers, and ice motion dominated by sliding at the bed. The fitting process involves an iterative process carried out in the time domain. Beginning with the portion of the ice sheet being modeled identical to the present ice sheet with uniform flow, sliding, and fraction specified at nominal values, the model monitors each nodal point surface elevation. As the calculated surface elevation deviates from the present surface, a correction proportional to the difference is applied to selected parameter sets. This correction is in a sense that would tend to improve the fit at the particular nodal point. A calculated surface elevation that was higher than the present surface would result in an increased fraction, which would tend to lower the calculated surface (if the flow or sliding constant were being used as the fitting parameter, they would be lowered to improve the fit). This process is allowed to proceed as long as is necessary for the situation to stabilize. Typically, this takes tens of thousands of model years, but the rate is dependent on other external forcings such as the accumulation rate. The primary result is that while a typical sample of ice streams from around Antarctica can be fitted quite reasonably using only the fraction of the velocity due to sliding, a different mechanism seems to be in play along the Siple Coast, where reduced sliding constants are required to attain a reasonable fit. Flow is more strongly channelized in this region, and velocities are, in general, higher than are observed in other regions. It is unlikely that the mechanism that controls the ice movement along the Siple Coast is exactly similar to the mechanisms in the other ice streams. The concept of deformable sediments and their contribution to the fast flow along

  4. Collective motion

    NASA Astrophysics Data System (ADS)

    Vicsek, Tamás; Zafeiris, Anna

    2012-08-01

    We review the observations and the basic laws describing the essential aspects of collective motion - being one of the most common and spectacular manifestation of coordinated behavior. Our aim is to provide a balanced discussion of the various facets of this highly multidisciplinary field, including experiments, mathematical methods and models for simulations, so that readers with a variety of background could get both the basics and a broader, more detailed picture of the field. The observations we report on include systems consisting of units ranging from macromolecules through metallic rods and robots to groups of animals and people. Some emphasis is put on models that are simple and realistic enough to reproduce the numerous related observations and are useful for developing concepts for a better understanding of the complexity of systems consisting of many simultaneously moving entities. As such, these models allow the establishing of a few fundamental principles of flocking. In particular, it is demonstrated, that in spite of considerable differences, a number of deep analogies exist between equilibrium statistical physics systems and those made of self-propelled (in most cases living) units. In both cases only a few well defined macroscopic/collective states occur and the transitions between these states follow a similar scenario, involving discontinuity and algebraic divergences.

  5. The need to differentiate the magnocellular system from the dorsal stream in connection with dyslexia.

    PubMed

    Skottun, Bernt C

    2015-04-01

    A number of authors have postulated a "magnocellular-dorsal stream" deficit in dyslexia. Combining the magnocellular system and the dorsal stream into a single entity in this context faces the problem that contrast sensitivity data do not point to a magnocellular deficiency linked to dyslexia, while, on the other hand, motion perception data are largely consistent with a dorsal stream dysfunction. Thus, there are data both for and against a "magnocellular-dorsal stream" deficit in connection with dyslexia. It is here pointed out that this inconsistency is abolished once it is recognized that the magnocellular system and the dorsal stream are separate entities.

  6. Explaining the "Pulse of Protoplasm": the search for molecular mechanisms of protoplasmic streaming.

    PubMed

    Dietrich, Michael R

    2015-01-01

    Explanations for protoplasmic streaming began with appeals to contraction in the eighteenth century and ended with appeals to contraction in the twentieth. During the intervening years, biologists proposed a diverse array of mechanisms for streaming motions. This paper focuses on the re-emergence of contraction among the molecular mechanisms proposed for protoplasmic streaming during the twentieth century. The revival of contraction is a result of a broader transition from colloidal chemistry to a macromolecular approach to the chemistry of proteins, the recognition of the phenomena of shuttle streaming and the pulse of protoplasm, and the influential analogy between protoplasmic streaming and muscle contraction.

  7. Wadeable Streams Assessment Data

    EPA Pesticide Factsheets

    The Wadeable Streams Assessment (WSA) is a first-ever statistically-valid survey of the biological condition of small streams throughout the U.S. The U.S. Environmental Protection Agency (EPA) worked with the states to conduct the assessment in 2004-2005. Data for each parameter sampled in the Wadeable Streams Assessment (WSA) are available for downloading in a series of files as comma separated values (*.csv). Each *.csv data file has a companion text file (*.txt) that lists a dataset label and individual descriptions for each variable. Users should view the *.txt files first to help guide their understanding and use of the data.

  8. Twitter Stream Archiver

    SciTech Connect

    Steed, Chad Allen

    2014-07-01

    The Twitter Archiver system allows a user to enter their Twitter developer account credentials (obtained separately from the Twitter developer website) and read from the freely available Twitter sample stream. The Twitter sample stream provides a random sample of the overall volume of tweets that are contributed by users to the system. The Twitter Archiver system consumes the stream and serializes the information to text files at some predefined interval. A separate utility reads the text files and creates a searchable index using the open source Apache Lucene text indexing system.

  9. Isentropic Analysis of Convective Motions

    NASA Technical Reports Server (NTRS)

    Pauluis, Olivier M.; Mrowiec, Agnieszka A.

    2013-01-01

    This paper analyzes the convective mass transport by sorting air parcels in terms of their equivalent potential temperature to determine an isentropic streamfunction. By averaging the vertical mass flux at a constant value of the equivalent potential temperature, one can compute an isentropic mass transport that filters out reversible oscillatory motions such as gravity waves. This novel approach emphasizes the fact that the vertical energy and entropy transports by convection are due to the combination of ascending air parcels with high energy and entropy and subsiding air parcels with lower energy and entropy. Such conditional averaging can be extended to other dynamic and thermodynamic variables such as vertical velocity, temperature, or relative humidity to obtain a comprehensive description of convective motions. It is also shown how this approach can be used to determine the mean diabatic tendencies from the three-dimensional dynamic and thermodynamic fields. A two-stream approximation that partitions the isentropic circulation into a mean updraft and a mean downdraft is also introduced. This offers a straightforward way to identify the mean properties of rising and subsiding air parcels. The results from the two-stream approximation are compared with two other definitions of the cloud mass flux. It is argued that the isentropic analysis offers a robust definition of the convective mass transport that is not tainted by the need to arbitrarily distinguish between convection and its environment, and that separates the irreversible convective overturning fromoscillations associated with gravity waves.

  10. A physical perspective on cytoplasmic streaming.

    PubMed

    Goldstein, Raymond E; van de Meent, Jan-Willem

    2015-08-06

    Organisms show a remarkable range of sizes, yet the dimensions of a single cell rarely exceed 100 µm. While the physical and biological origins of this constraint remain poorly understood, exceptions to this rule give valuable insights. A well-known counterexample is the aquatic plant Chara, whose cells can exceed 10 cm in length and 1 mm in diameter. Two spiralling bands of molecular motors at the cell periphery drive the cellular fluid up and down at speeds up to 100 µm s(-1), motion that has been hypothesized to mitigate the slowness of metabolite transport on these scales and to aid in homeostasis. This is the most organized instance of a broad class of continuous motions known as 'cytoplasmic streaming', found in a wide range of eukaryotic organisms-algae, plants, amoebae, nematodes and flies-often in unusually large cells. In this overview of the physics of this phenomenon, we examine the interplay between streaming, transport and cell size and discuss the possible role of self-organization phenomena in establishing the observed patterns of streaming.

  11. Self Motion Perception and Motion Sickness

    NASA Technical Reports Server (NTRS)

    Fox, Robert A. (Principal Investigator)

    1991-01-01

    The studies conducted in this research project examined several aspects of motion sickness in animal models. A principle objective of these studies was to investigate the neuroanatomy that is important in motion sickness with the objectives of examining both the utility of putative models and defining neural mechanisms that are important in motion sickness.

  12. Urban Stream Ecology

    EPA Science Inventory

    Urban watersheds characteristically have high impervious surface cover, resulting in high surface runoff and low infiltration following storms. In response, urban streams experience “flashy” stormflows, reduced baseflows, bank erosion, channel widening, and sedimentation. Urban ...

  13. Stochastic ice stream dynamics

    NASA Astrophysics Data System (ADS)

    Mantelli, Elisa; Bertagni, Matteo Bernard; Ridolfi, Luca

    2016-08-01

    Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.

  14. Streaming tearing mode

    NASA Technical Reports Server (NTRS)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  15. Stochastic ice stream dynamics

    PubMed Central

    Bertagni, Matteo Bernard; Ridolfi, Luca

    2016-01-01

    Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution. PMID:27457960

  16. Discontinuous ephemeral streams

    NASA Astrophysics Data System (ADS)

    Bull, William B.

    1997-07-01

    Many ephemeral streams in western North America flowed over smooth valley floors before transformation from shallow discontinuous channels into deep arroyos. These inherently unstable streams of semiarid regions are sensitive to short-term climatic changes, and to human impacts, because hillslopes supply abundant sediment to infrequent large streamflow events. Discontinuous ephemeral streams appear to be constantly changing as they alternate between two primary modes of operation; either aggradation or degradation may become dominant. Attainment of equilibrium conditions is brief. Disequilibrium is promoted by channel entrenchment that causes the fall of local base level, and by deposition of channel fans that causes the rise of local base level. These opposing base-level processes in adjacent reaches are maintained by self-enhancing feedback mechanisms. The threshold between erosion and deposition is crossed when aggradational or degradational reaches shift upstream or downstream. Extension of entrenched reaches into channel fans tends to create continuous arroyos. Upvalley migration of fan apexes tends to create depositional valley floors with few stream channels. Less than 100 years is required for arroyo cutting, but more than 500 years is required for complete aggradation of entrenched stream channels and valley floors. Discontinuous ephemeral streams have a repetitive sequence of streamflow characteristics that is as distinctive as sequences of meander bends or braided gravel bars in perennial rivers. The sequence changes from degradation to aggradation — headcuts concentrate sheetflow, a single trunk channel conveys flow to the apex of a channel fan, braided distributary channels end in an area of diverging sheetflow, and converging sheetflow drains to headcuts. The sequence is repeated at intervals ranging from 15 m for small streams to more than 10 km for large streams. Lithologic controls on the response of discontinuous ephemeral streams include: (1

  17. Android Video Streaming

    DTIC Science & Technology

    2014-05-01

    Android Video Streaming by Jonathan Fletcher, David Doria, and David Bruno ARL-TR-6947 May 2014...the originator. Army Research Laboratory Aberdeen Proving Ground, MD 21005-5067 ARL-TR-6947 May 2014 Android Video Streaming...1. REPORT DATE (DD-MM-YYYY) May 2014 2. REPORT TYPE Final 3. DATES COVERED (From - To) July 2013–September 2013 4. TITLE AND SUBTITLE Android

  18. Gulf stream separation dynamics

    NASA Astrophysics Data System (ADS)

    Schoonover, Joseph

    Climate models currently struggle with the more traditional, coarse ( O(100 km) ) representation of the ocean. In these coarse ocean simulations, western boundary currents are notoriously difficult to model accurately. The modeled Gulf Stream is typically seen exhibiting a mean pathway that is north of observations, and is linked to a warm sea-surface temperature bias in the Mid-Atlantic Bight. Although increased resolution ( O(10 km) ) improves the modeled Gulf Stream position, there is no clean recipe for obtaining the proper pathway. The 70 year history of literature on the Gulf Stream separation suggests that we have not reached a resolution on the dynamics that control the current's pathway just south of the Mid-Atlantic Bight. Without a concrete knowledge on the separation dynamics, we cannot provide a clean recipe for accurately modeling the Gulf Stream at increased resolutions. Further, any reliable parameterization that yields a realistic Gulf Stream path must express the proper physics of separation. The goal of this dissertation is to determine what controls the Gulf Stream separation. To do so, we examine the results of a model intercomparison study and a set of numerical regional terraforming experiments. It is argued that the separation is governed by local dynamics that are most sensitive to the steepening of the continental shelf, consistent with the topographic wave arrest hypothesis of Stern (1998). A linear extension of Stern's theory is provided, which illustrates that wave arrest is possible for a continuously stratified fluid.

  19. The role of human ventral visual cortex in motion perception.

    PubMed

    Gilaie-Dotan, Sharon; Saygin, Ayse P; Lorenzi, Lauren J; Egan, Ryan; Rees, Geraint; Behrmann, Marlene

    2013-09-01

    Visual motion perception is fundamental to many aspects of visual perception. Visual motion perception has long been associated with the dorsal (parietal) pathway and the involvement of the ventral 'form' (temporal) visual pathway has not been considered critical for normal motion perception. Here, we evaluated this view by examining whether circumscribed damage to ventral visual cortex impaired motion perception. The perception of motion in basic, non-form tasks (motion coherence and motion detection) and complex structure-from-motion, for a wide range of motion speeds, all centrally displayed, was assessed in five patients with a circumscribed lesion to either the right or left ventral visual pathway. Patients with a right, but not with a left, ventral visual lesion displayed widespread impairments in central motion perception even for non-form motion, for both slow and for fast speeds, and this held true independent of the integrity of areas MT/V5, V3A or parietal regions. In contrast with the traditional view in which only the dorsal visual stream is critical for motion perception, these novel findings implicate a more distributed circuit in which the integrity of the right ventral visual pathway is also necessary even for the perception of non-form motion.

  20. Self-Motion Perception and Motion Sickness

    NASA Technical Reports Server (NTRS)

    Fox, Robert A.

    1991-01-01

    Motion sickness typically is considered a bothersome artifact of exposure to passive motion in vehicles of conveyance. This condition seldom has significant impact on the health of individuals because it is of brief duration, it usually can be prevented by simply avoiding the eliciting condition and, when the conditions that produce it are unavoidable, sickness dissipates with continued exposure. The studies conducted examined several aspects of motion sickness in animal models. A principle objective of these studies was to investigate the neuroanatomy that is important in motion sickness with the objectives of examining both the utility of putative models and defining neural mechanisms that are important in motion sickness.

  1. Isentropic analysis of polar cold air mass streams

    NASA Astrophysics Data System (ADS)

    Iwasaki, Toshiki; Kanno, Yuki

    2015-04-01

    1. Introduction A diagnostic method is presented of polar cold air mass streams defined below a threshold potential temperature. The isentropic threshold facilitates a Lagrangian view of the cold air mass streams from diabatic generation to disappearance. 2. Mass-weighted isentropic zonal mean (MIM) cold air streams In winter hemispheres, MIM's mass stream functions show a distinct extratropical direct (ETD) cell in addition to the Hadley cell. The mass stream functions have local maxima at around (280K, 45N) for NH winter and, around (280K, 50S) for SH winter. Thus, =280K may be appropriate to a threshold of the polar cold air mass for both hemispheres. The high-latitude downward motion indicates the diabatic generation of cold air mass, whereas the mid-latitude equatorward flow does its outbreak. The strength of equatorward flow is under significant control of wave-mean flow interactions. 3. Geographical distribution of the cold air mass streams in the NH winter In the NH winter, the polar cold air mass flux has two distinct mainstreams, hereafter called as East Asian (EA) stream and the North American (NA) stream. The former grows over the northern part of the Eurasian continent, turns down southeastward toward East Asia and disappears over the western North Pacific Ocean. The latter grows over the Arctic Ocean, flows toward the East Coast of North America and disappears over the western North Atlantic Ocean. These coincide well with main routes of cold surges. 4. Comparison between NH and SH winter streams The cold air mass streams in NH winter are more asymmetric than those in SH winter. The NH total cold air mass below =280K is about 1.5 times greater than the SH one. These come mainly from the topography and land-sea distribution. The mid-latitude mountains steer the cold air mass streams on the northern sides and enhance the residence time over its genesis region.

  2. Coincident vortices in Antarctic wind fields and sea ice motion

    NASA Astrophysics Data System (ADS)

    Wassermann, S.; Schmitt, C.; Kottmeier, C.; Simmonds, I.

    2006-08-01

    This study introduces a method to examine the coincidence of rotational ice drift and winds caused by the forcing of ice motion by Antarctic cyclones. Vortices are automatically detected using the algorithm of Murray and Simmonds (1991) from both ECMWF surface pressures and SSM/I sea ice motions. For compatibility with this algorithm sea ice motion vectors are transformed to a scalar stream function. During a seven-day test period positions of pressure minima and stream function maxima (SFM) of ice drift are within 300 km in 96% of the cases. Lowest pressure minima are related to highest stream function maxima. The results promise the method to provide a complementary tool of detecting and localizing low-pressure systems over sea ice, adding to numerical pressure analyses.

  3. Fully scalable video coding with packed stream

    NASA Astrophysics Data System (ADS)

    Lopez, Manuel F.; Rodriguez, Sebastian G.; Ortiz, Juan Pablo; Dana, Jose Miguel; Ruiz, Vicente G.; Garcia, Inmaculada

    2005-03-01

    Scalable video coding is a technique which allows a compressed video stream to be decoded in several different ways. This ability allows a user to adaptively recover a specific version of a video depending on its own requirements. Video sequences have temporal, spatial and quality scalabilities. In this work we introduce a novel fully scalable video codec. It is based on a motion-compensated temporal filtering (MCTF) of the video sequences and it uses some of the basic elements of JPEG 2000. This paper describes several specific proposals for video on demand and video-conferencing applications over non-reliable packet-switching data networks.

  4. Montana StreamStats

    USGS Publications Warehouse

    2016-04-05

    About this volumeMontana StreamStats is a Web-based geographic information system (http://water.usgs.gov/osw/streamstats/) application that provides users with access to basin and streamflow characteristics for gaged and ungaged streams in Montana. Montana StreamStats was developed by the U.S. Geological Survey (USGS) in cooperation with the Montana Departments of Transportation, Environmental Quality, and Natural Resources and Conservation. The USGS Scientific Investigations Report consists of seven independent but complementary chapters dealing with various aspects of this effort.Chapter A describes the Montana StreamStats application, the basin and streamflow datasets, and provides a brief overview of the streamflow characteristics and regression equations used in the study. Chapters B through E document the datasets, methods, and results of analyses to determine streamflow characteristics, such as peak-flow frequencies, low-flow frequencies, and monthly and annual characteristics, for USGS streamflow-gaging stations in and near Montana. The StreamStats analytical toolsets that allow users to delineate drainage basins and solve regression equations to estimate streamflow characteristics at ungaged sites in Montana are described in Chapters F and G.

  5. Meandering stream reservoirs

    SciTech Connect

    Richardson, J.G.; Sangree, J.B.; Sneider, R.M.

    1987-12-01

    Braided stream deposits, described in a previous article in this series, and meandering stream deposits commonly are excellent reservoirs. Meandering high-sinuousity channels are found on flat alluvial plains with slopes less than 1 1/2/sup 0/ (0.026 rad). These rivers have wide ranges of discharges from low-water flow to flood stage. Two main processes are responsible for development of sand bodies. These are point-bar deposits left by channel migration, and oxbow-lake deposits left in loops of the river course abandoned when the stream cuts a new course during flooding. Extremely high floods spill over the banks and deposit sheets of very fine sand, silt, and clay onto the flood plain.

  6. An Orbit Fit for the Grillmair Dionatos Cold Stellar Stream

    SciTech Connect

    Willett, Benjamin A.; Newberg, Heidi Jo; Zhang, Haotong; Yanny, Brian; Beers, Timothy C.

    2009-01-01

    We use velocity and metallicity information from Sloan Digital Sky Survey and Sloan Extension for Galactic Understanding and Exploration stellar spectroscopy to fit an orbit to the narrow 63{sup o} stellar stream of Grillmair and Dionatos. The stars in the stream have a retrograde orbit with eccentricity e = 0.33 (perigalacticon of 14.4 kpc and apogalacticon of 28.7 kpc) and inclination approximately i {approx} 35{sup o}. In the region of the orbit which is detected, it has a distance of about 7-11 kpc from the Sun. Assuming a standard disk plus bulge and logarithmic halo potential for the Milky Way stars plus dark matter, the stream stars are moving with a large space velocity of approximately 276 km s{sup -1} at perigalacticon. Using this stream alone, we are unable to determine if the dark matter halo is oblate or prolate. The metallicity of the stream is [Fe/H] = -2.1 {+-} 0.1. Observed proper motions for individual stream members above the main sequence turnoff are consistent with the derived orbit. None of the known globular clusters in the Milky Way have positions, radial velocities, and metallicities that are consistent with being the progenitor of the GD-1 stream.

  7. Practical Meteor Stream Forecasting

    NASA Technical Reports Server (NTRS)

    Cooke, William J.; Suggs, Robert M.

    2003-01-01

    Inspired by the recent Leonid meteor storms, researchers have made great strides in our ability to predict enhanced meteor activity. However, the necessary calibration of the meteor stream models with Earth-based ZHRs (Zenith Hourly Rates) has placed emphasis on the terran observer and meteor activity predictions are published in such a manner to reflect this emphasis. As a consequence, many predictions are often unusable by the satellite community, which has the most at stake and the greatest interest in meteor forecasting. This paper suggests that stream modelers need to pay more attention to the needs of this community and publish not just durations and times of maxima for Earth, but everything needed to characterize the meteor stream in and out of the plane of the ecliptic, which, at a minimum, consists of the location of maximum stream density (ZHR) and the functional form of the density decay with distance from this point. It is also suggested that some of the terminology associated with meteor showers may need to be more strictly defined in order to eliminate the perception of crying wolf by meteor scientists. An outburst is especially problematic, as it usually denotes an enhancement by a factor of 2 or more to researchers, but conveys the notion of a sky filled with meteors to satellite operators and the public. Experience has also taught that predicted ZHRs often lead to public disappointment, as these values vastly overestimate what is seen.

  8. Toward Third Stream Evaluation.

    ERIC Educational Resources Information Center

    Della-Piana, Gabriel M.; Endo, George T.

    Third stream evaluation, the fusing of the ecological perspective with experimental or quasi-experimental evaluation design, is described. The ecological perspective necessitates that the conceptualization and analysis of a setting and the design of the study emphasize the interdependent relations among organisms, behavior and environment in…

  9. Visualizing and Quantifying Oceanic Motion.

    PubMed

    Rossby, T

    2016-01-01

    Here I review the use of two highly complementary acoustical technologies for measuring currents in the ocean: acoustically tracked neutrally buoyant floats and vessel-mounted acoustic Doppler current profilers (ADCPs). The beauty of floats lies in their ability to efficiently and accurately visualize fluid motion in fronts and vortices and the dispersion caused by mesoscale eddy processes. Floats complement classical hydrography by articulating mechanisms and pathways by which waters spread out from their source region. Vessel-mounted ADCPs can profile the water column at O(1 km) horizontal resolution to depths greater than 1,000 m. These vessel-based scans capture in detail the cross-stream structure of fronts and eddies as well as the impact of bathymetry on currents. Sustained sampling along selected routes builds up valuable databases both for statistical studies of the submesoscale velocity field and for accurate estimates of fluid transport, as well as how these vary over time.

  10. Visualizing and Quantifying Oceanic Motion

    NASA Astrophysics Data System (ADS)

    Rossby, T.

    2016-01-01

    Here I review the use of two highly complementary acoustical technologies for measuring currents in the ocean: acoustically tracked neutrally buoyant floats and vessel-mounted acoustic Doppler current profilers (ADCPs). The beauty of floats lies in their ability to efficiently and accurately visualize fluid motion in fronts and vortices and the dispersion caused by mesoscale eddy processes. Floats complement classical hydrography by articulating mechanisms and pathways by which waters spread out from their source region. Vessel-mounted ADCPs can profile the water column at O(1 km) horizontal resolution to depths greater than 1,000 m. These vessel-based scans capture in detail the cross-stream structure of fronts and eddies as well as the impact of bathymetry on currents. Sustained sampling along selected routes builds up valuable databases both for statistical studies of the submesoscale velocity field and for accurate estimates of fluid transport, as well as how these vary over time.

  11. ASSESSING HEADWATER STREAMS: LINKING LANDSCAPES TO STREAM NETWORKS

    EPA Science Inventory

    Headwater streams represent a significant land-water boundary and drain 70-80% of the landscape. Headwater streams are vital components to drainage systems and are directly linked to our downstream rivers and lakes. However, alteration and loss of headwater streams have occurre...

  12. A physical perspective on cytoplasmic streaming

    PubMed Central

    Goldstein, Raymond E.; van de Meent, Jan-Willem

    2015-01-01

    Organisms show a remarkable range of sizes, yet the dimensions of a single cell rarely exceed 100 µm. While the physical and biological origins of this constraint remain poorly understood, exceptions to this rule give valuable insights. A well-known counterexample is the aquatic plant Chara, whose cells can exceed 10 cm in length and 1 mm in diameter. Two spiralling bands of molecular motors at the cell periphery drive the cellular fluid up and down at speeds up to 100 µm s−1, motion that has been hypothesized to mitigate the slowness of metabolite transport on these scales and to aid in homeostasis. This is the most organized instance of a broad class of continuous motions known as ‘cytoplasmic streaming’, found in a wide range of eukaryotic organisms—algae, plants, amoebae, nematodes and flies—often in unusually large cells. In this overview of the physics of this phenomenon, we examine the interplay between streaming, transport and cell size and discuss the possible role of self-organization phenomena in establishing the observed patterns of streaming. PMID:26464789

  13. A Simulated Stream Ecology Study.

    ERIC Educational Resources Information Center

    Zampella, Robert A.

    1979-01-01

    Describes a simulated field experience to study stream ecology in the classroom. Secondary students determine the composition of the stream community, describe the distribution of the benthic invertebrates, and design a food web. (Author/MA)

  14. The Debris Streams from Tidal Disruption Events

    NASA Astrophysics Data System (ADS)

    Coughlin, Eric

    2016-01-01

    When a star comes within a critical distance of a supermassive black hole, the tidal force exerted by the hole overcomes the stellar self-gravity. The star is subsequently torn apart, creating a stream of tidally-shredded debris that initially recedes from the hole, eventually returns to pericenter, forms an accretion disk and generates a highly luminous event that can sometimes be accompanied by the production of relativistic jets. This entire process is known as a tidal disruption event (TDE), and dozens of these events have already been observed. I will discuss my most recent work that has analyzed the tidal disruption process, and in particular I will focus on the results of numerical and analytical investigations that show that the streams of debris produced during TDEs can be gravitationally unstable. Specifically, I will describe how compressive motions augment the importance of self-gravity not long after the star is disrupted, resulting in the fragmentation of the debris stream into small-scale clumps. These findings will be discussed in the context of the observational signatures of tidal disruption events, and I will also relate these results to my past investigations concerning accretion disk formation and jet launching during TDEs.

  15. Objects in Motion

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

    One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

  16. Stream Channel Stability.

    DTIC Science & Technology

    1981-04-01

    geometry of the stilling basin and appurtenances for optimum energy dissipation. The hydraulic design, based on a 100-year return period design storm...cases the only viable alternative based on present technology is to let the channel seek its oa equilibrium, but attempt to minimize total losses by...are degrading, resulting in bank caving, land loss , and damage to highway bridges. Many streams have enlarged to the extent that 50 to 100-year runoff

  17. Autonomous Byte Stream Randomizer

    NASA Technical Reports Server (NTRS)

    Paloulian, George K.; Woo, Simon S.; Chow, Edward T.

    2013-01-01

    Net-centric networking environments are often faced with limited resources and must utilize bandwidth as efficiently as possible. In networking environments that span wide areas, the data transmission has to be efficient without any redundant or exuberant metadata. The Autonomous Byte Stream Randomizer software provides an extra level of security on top of existing data encryption methods. Randomizing the data s byte stream adds an extra layer to existing data protection methods, thus making it harder for an attacker to decrypt protected data. Based on a generated crypto-graphically secure random seed, a random sequence of numbers is used to intelligently and efficiently swap the organization of bytes in data using the unbiased and memory-efficient in-place Fisher-Yates shuffle method. Swapping bytes and reorganizing the crucial structure of the byte data renders the data file unreadable and leaves the data in a deconstructed state. This deconstruction adds an extra level of security requiring the byte stream to be reconstructed with the random seed in order to be readable. Once the data byte stream has been randomized, the software enables the data to be distributed to N nodes in an environment. Each piece of the data in randomized and distributed form is a separate entity unreadable on its own right, but when combined with all N pieces, is able to be reconstructed back to one. Reconstruction requires possession of the key used for randomizing the bytes, leading to the generation of the same cryptographically secure random sequence of numbers used to randomize the data. This software is a cornerstone capability possessing the ability to generate the same cryptographically secure sequence on different machines and time intervals, thus allowing this software to be used more heavily in net-centric environments where data transfer bandwidth is limited.

  18. Numerical study of fluid motion in bioreactor with two mixers

    SciTech Connect

    Zheleva, I.; Lecheva, A.

    2015-10-28

    Numerical study of hydrodynamic laminar behavior of a viscous fluid in bioreactor with multiple mixers is provided in the present paper. The reactor is equipped with two disk impellers. The fluid motion is studied in stream function-vorticity formulation. The calculations are made by a computer program, written in MATLAB. The fluid structure is described and numerical results are graphically presented and commented.

  19. Gas stream cleanup

    SciTech Connect

    Bossart, S.J.; Cicero, D.C.; Zeh, C.M.; Bedick, R.C.

    1990-08-01

    This report describes the current status and recent accomplishments of gas stream cleanup (GSCU) projects sponsored by the Morgantown Energy Technology Center (METC) of the US Department of Energy (DOE). The primary goal of the Gas Stream Cleanup Program is to develop contaminant control strategies that meet environmental regulations and protect equipment in advanced coal conversion systems. Contaminant control systems are being developed for integration into seven advanced coal conversion processes: Pressurized fludized-bed combustion (PFBC), Direct coal-fueled turbine (DCFT), Intergrated gasification combined-cycle (IGCC), Gasification/molten carbonate fuel cell (MCFC), Gasification/solid oxide fuel cell (SOFC), Coal-fueled diesel (CFD), and Mild gasification (MG). These advanced coal conversion systems present a significant challenge for development of contaminant control systems because they generate multi-contaminant gas streams at high-pressures and high temperatures. Each of the seven advanced coal conversion systems incorporates distinct contaminant control strategies because each has different contaminant tolerance limits and operating conditions. 59 refs., 17 figs., 5 tabs.

  20. The LHCb Turbo stream

    NASA Astrophysics Data System (ADS)

    Puig, A.

    2016-07-01

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process this data, which limits the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the Turbo stream the trigger will write out a compact summary of physics objects containing all information necessary for analyses. This will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during 2015 with a selection of physics analyses. It is anticipated that the turbo stream will be adopted by an increasing number of analyses during the remainder of LHC Run II (2015-2018) and ultimately in Run III (starting in 2020) with the upgraded LHCb detector.

  1. Stream processing health card application.

    PubMed

    Polat, Seda; Gündem, Taflan Imre

    2012-10-01

    In this paper, we propose a data stream management system embedded to a smart card for handling and storing user specific summaries of streaming data coming from medical sensor measurements and/or other medical measurements. The data stream management system that we propose for a health card can handle the stream data rates of commonly known medical devices and sensors. It incorporates a type of context awareness feature that acts according to user specific information. The proposed system is cheap and provides security for private data by enhancing the capabilities of smart health cards. The stream data management system is tested on a real smart card using both synthetic and real data.

  2. Dual motion valve with single motion input

    NASA Technical Reports Server (NTRS)

    Belew, Robert (Inventor)

    1987-01-01

    A dual motion valve includes two dual motion valve assemblies with a rotary input which allows the benefits of applying both rotary and axial motion to a rotary sealing element with a plurality of ports. The motion of the rotary sealing element during actuation provides axial engagement of the rotary sealing element with a stationary valve plate which also has ports. Fluid passages are created through the valve when the ports of the rotary sealing element are aligned with the ports of the stationary valve plate. Alignment is achieved through rotation of the rotary sealing element with respect to the stationary valve plate. The fluid passages provide direct paths which minimize fluid turbulence created in the fluid as it passes through the valve.

  3. Influence of the Gulf Stream on the troposphere.

    PubMed

    Minobe, Shoshiro; Kuwano-Yoshida, Akira; Komori, Nobumasa; Xie, Shang-Ping; Small, Richard Justin

    2008-03-13

    The Gulf Stream transports large amounts of heat from the tropics to middle and high latitudes, and thereby affects weather phenomena such as cyclogenesis and low cloud formation. But its climatic influence, on monthly and longer timescales, remains poorly understood. In particular, it is unclear how the warm current affects the free atmosphere above the marine atmospheric boundary layer. Here we consider the Gulf Stream's influence on the troposphere, using a combination of operational weather analyses, satellite observations and an atmospheric general circulation model. Our results reveal that the Gulf Stream affects the entire troposphere. In the marine boundary layer, atmospheric pressure adjustments to sharp sea surface temperature gradients lead to surface wind convergence, which anchors a narrow band of precipitation along the Gulf Stream. In this rain band, upward motion and cloud formation extend into the upper troposphere, as corroborated by the frequent occurrence of very low cloud-top temperatures. These mechanisms provide a pathway by which the Gulf Stream can affect the atmosphere locally, and possibly also in remote regions by forcing planetary waves. The identification of this pathway may have implications for our understanding of the processes involved in climate change, because the Gulf Stream is the upper limb of the Atlantic meridional overturning circulation, which has varied in strength in the past and is predicted to weaken in response to human-induced global warming in the future.

  4. Directional motion of liquid under mechanical vibrations

    NASA Astrophysics Data System (ADS)

    Costalonga, Maxime; Brunet, Philippe; Peerhossaini, Hassan

    2014-11-01

    When a liquid is submitted to mechanical vibrations, steady flows or motion can be generated by non-linear effects. One example is the steady acoustic streaming one can observe when an acoustic wave propagates in a fluid. At the scale of a droplet, steady motion of the whole amount of liquid can arise from zero-mean periodic forcing. As It has been observed by Brunet et al. (PRL 2007), a drop can climb an inclined surface when submitted to vertical vibrations above a threshold in acceleration. Later, Noblin et al. (PRL 2009) showed the velocity and the direction of motion of a sessile drop submitted to both horizontal and vertical vibrations can be tuned by the phase shift between these two excitations. Here we present an experimental study of the mean motion of a sessile drop under slanted vibrations, focusing on the effects of drop properties, as well as the inclination angle of the axis of vibrations. It is shown that the volume and viscosity strongly affect the drop mean velocity, and can even change the direction of its motion. In the case of a low viscous drop, gravity can become significant and be modulated by the inclination of the axis of vibrations. Contact line dynamic during the drop oscillations is also investigated.

  5. Attentive Motion Discrimination Recruits an Area in Inferotemporal Cortex.

    PubMed

    Stemmann, Heiko; Freiwald, Winrich A

    2016-11-23

    Attentional selection requires the interplay of multiple brain areas. Theoretical accounts of selective attention predict different areas with different functional properties to support endogenous covert attention. To test these predictions, we devised a demanding attention task requiring motion discrimination and spatial selection and performed whole-brain imaging in macaque monkeys. Attention modulated the early visual cortex, motion-selective dorsal stream areas, the lateral intraparietal area, and the frontal eye fields. This pattern of activation supports early selection, feature-based, and biased-competition attention accounts, as well as the frontoparietal theory of attentional control. While high-level motion-selective dorsal stream areas did not exhibit strong attentional modulation, ventral stream areas V4d and the dorsal posterior inferotemporal cortex (PITd) did. The PITd in fact was, consistently across task variations, the most significantly and most strongly attention-modulated area, even though it did not exhibit signs of motion selectivity. Thus the recruitment of the PITd in attention tasks involving different kinds of motion analysis is not predicted by any theoretical account of attention. These functional data, together with known anatomical connections, suggest a general and possibly critical role of the PITd in attentional selection.

  6. The Phoenix stream: A cold stream in the southern hemisphere

    DOE PAGES

    Balbinot, E.

    2016-03-17

    In this study, we report the discovery of a stellar stream in the Dark Energy Survey (DES) Year 1 (Y1A1) data. The discovery was made through simple color-magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color-magnitude space, we find that a stellar population with agemore » $$\\tau=11.5\\pm0.5$$ Gyr and $[Fe/H]<-1.6$ located 17.5$$\\pm$$0.9 kpc from the Sun gives an adequate description of the stream stellar population. The stream is detected over an extension of 8$$^{\\circ}.$$1 (2.5 kpc) and has a width of $$\\sim$$54 pc assuming a Gaussian profile, indicating that a globular cluster is a probable progenitor. There is no known globular cluster within 5 kpc compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities along the stream, however no obvious counterpart bound stellar system is visible in the coadded images. We also find overdensities along the stream that appear to be symmetrically distributed - consistent with the epicyclic overdensity scenario for the formation of cold streams - as well as a misalignment between the Northern and Southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe overdensity (Li et al. 2016).« less

  7. The Phoenix stream: A cold stream in the southern hemisphere

    SciTech Connect

    Balbinot, E.

    2016-03-17

    In this study, we report the discovery of a stellar stream in the Dark Energy Survey (DES) Year 1 (Y1A1) data. The discovery was made through simple color-magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color-magnitude space, we find that a stellar population with age $\\tau=11.5\\pm0.5$ Gyr and $[Fe/H]<-1.6$ located 17.5$\\pm$0.9 kpc from the Sun gives an adequate description of the stream stellar population. The stream is detected over an extension of 8$^{\\circ}.$1 (2.5 kpc) and has a width of $\\sim$54 pc assuming a Gaussian profile, indicating that a globular cluster is a probable progenitor. There is no known globular cluster within 5 kpc compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities along the stream, however no obvious counterpart bound stellar system is visible in the coadded images. We also find overdensities along the stream that appear to be symmetrically distributed - consistent with the epicyclic overdensity scenario for the formation of cold streams - as well as a misalignment between the Northern and Southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe overdensity (Li et al. 2016).

  8. STREAM2016: Streaming Requirements, Experience, Applications and Middleware Workshop

    SciTech Connect

    Fox, Geoffrey; Jha, Shantenu; Ramakrishnan, Lavanya

    2016-10-01

    The Department of Energy (DOE) Office of Science (SC) facilities including accelerators, light sources and neutron sources and sensors that study, the environment, and the atmosphere, are producing streaming data that needs to be analyzed for next-generation scientific discoveries. There has been an explosion of new research and technologies for stream analytics arising from the academic and private sectors. However, there has been no corresponding effort in either documenting the critical research opportunities or building a community that can create and foster productive collaborations. The two-part workshop series, STREAM: Streaming Requirements, Experience, Applications and Middleware Workshop (STREAM2015 and STREAM2016), were conducted to bring the community together and identify gaps and future efforts needed by both NSF and DOE. This report describes the discussions, outcomes and conclusions from STREAM2016: Streaming Requirements, Experience, Applications and Middleware Workshop, the second of these workshops held on March 22-23, 2016 in Tysons, VA. STREAM2016 focused on the Department of Energy (DOE) applications, computational and experimental facilities, as well software systems. Thus, the role of “streaming and steering” as a critical mode of connecting the experimental and computing facilities was pervasive through the workshop. Given the overlap in interests and challenges with industry, the workshop had significant presence from several innovative companies and major contributors. The requirements that drive the proposed research directions, identified in this report, show an important opportunity for building competitive research and development program around streaming data. These findings and recommendations are consistent with vision outlined in NRC Frontiers of Data and National Strategic Computing Initiative (NCSI) [1, 2]. The discussions from the workshop are captured as topic areas covered in this report's sections. The report discusses

  9. Riparian deforestation, stream narrowing, and loss of stream ecosystem services

    PubMed Central

    Sweeney, Bernard W.; Bott, Thomas L.; Jackson, John K.; Kaplan, Louis A.; Newbold, J. Denis; Standley, Laurel J.; Hession, W. Cully; Horwitz, Richard J.

    2004-01-01

    A study of 16 streams in eastern North America shows that riparian deforestation causes channel narrowing, which reduces the total amount of stream habitat and ecosystem per unit channel length and compromises in-stream processing of pollutants. Wide forest reaches had more macroinvertebrates, total ecosystem processing of organic matter, and nitrogen uptake per unit channel length than contiguous narrow deforested reaches. Stream narrowing nullified any potential advantages of deforestation regarding abundance of fish, quality of dissolved organic matter, and pesticide degradation. These findings show that forested stream channels have a wider and more natural configuration, which significantly affects the total in-stream amount and activity of the ecosystem, including the processing of pollutants. The results reinforce both current policy of the United States that endorses riparian forest buffers as best management practice and federal and state programs that subsidize riparian reforestation for stream restoration and water quality. Not only do forest buffers prevent nonpoint source pollutants from entering small streams, they also enhance the in-stream processing of both nonpoint and point source pollutants, thereby reducing their impact on downstream rivers and estuaries. PMID:15381768

  10. Riparian deforestation, stream narrowing, and loss of stream ecosystem services.

    PubMed

    Sweeney, Bernard W; Bott, Thomas L; Jackson, John K; Kaplan, Louis A; Newbold, J Denis; Standley, Laurel J; Hession, W Cully; Horwitz, Richard J

    2004-09-28

    A study of 16 streams in eastern North America shows that riparian deforestation causes channel narrowing, which reduces the total amount of stream habitat and ecosystem per unit channel length and compromises in-stream processing of pollutants. Wide forest reaches had more macroinvertebrates, total ecosystem processing of organic matter, and nitrogen uptake per unit channel length than contiguous narrow deforested reaches. Stream narrowing nullified any potential advantages of deforestation regarding abundance of fish, quality of dissolved organic matter, and pesticide degradation. These findings show that forested stream channels have a wider and more natural configuration, which significantly affects the total in-stream amount and activity of the ecosystem, including the processing of pollutants. The results reinforce both current policy of the United States that endorses riparian forest buffers as best management practice and federal and state programs that subsidize riparian reforestation for stream restoration and water quality. Not only do forest buffers prevent nonpoint source pollutants from entering small streams, they also enhance the in-stream processing of both nonpoint and point source pollutants, thereby reducing their impact on downstream rivers and estuaries.

  11. Motion through syntactic frames.

    PubMed

    Feist, Michele I

    2010-04-01

    The introduction of Talmy's (1985, 2000) typology sparked significant interest in linguistic relativity in the arena of motion language. Through careful analysis of the conflation patterns evident in the language of motion events, Talmy noted that one class of languages, V-languages, tends to encode path along with the fact of motion in motion verbs, while a second class, S-languages, tends to encode manner. In the experimental literature, it was reasoned that speakers may be expected to extend novel verbs in accordance with the lexicalization patterns of their native languages. However, the results regarding this prediction are mixed. In this paper, I examine the interplay between the meaning encoded in the motion verb itself and the meaning encoded in the motion description construction, offering a Gricean explanation for co-occurrence patterns and, by extension, for the mixed results. I then explore the implications of this argument for research on possible language effects on thought in this domain.

  12. Motion Tracking System

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Integrated Sensors, Inc. (ISI), under NASA contract, developed a sensor system for controlling robot vehicles. This technology would enable a robot supply vehicle to automatically dock with Earth-orbiting satellites or the International Space Station. During the docking phase the ISI-developed sensor must sense the satellite's relative motion, then spin so the robot vehicle can adjust its motion to align with the satellite and slowly close until docking is completed. ISI used the sensing/tracking technology as the basis of its OPAD system, which simultaneously tracks an object's movement in six degrees of freedom. Applications include human limb motion analysis, assembly line position analysis and auto crash dummy motion analysis. The NASA technology is also the basis for Motion Analysis Workstation software, a package to simplify the video motion analysis process.

  13. Absolute Proper Motions and Chemical Abundances of Stars Along the Sagittarius Trailing Tidal Tail

    NASA Astrophysics Data System (ADS)

    Carlin, Jeffrey L.; Majewski, S. R.; Casetti-Dinescu, D. I.; Patterson, R. J.

    2010-01-01

    We show results from our deep proper-motion survey of Kapteyn's Selected Areas (SAs; Casetti-Dinescu et al. 2006, AJ,132,2082), with a focus on fields that intersect the Sagittarius (Sgr) trailing tidal stream. Our data set, derived from matched, deep photographic plate pairs taken nearly 100 years apart, provides a unique window on the motions of stars in these SA fields. We find the signature of a common-motion population among our accurate proper motions of stars in five of these fields, as well as corresponding stellar excesses which are identified as stellar debris from the disrupted Sgr dwarf. Spectroscopic follow-up confirms that these stars are Sgr members, and the resultant radial velocities and spectroscopic parallaxes are combined with proper motions to derive full space motions of 30-100 tidal stream members per field. These kinematical data are compared to the predictions of the Law et al. (2009, ApJL,703,67) models of Sgr disruption, which have thus far reproduced most observed features of the Sgr stream, and have also constrained the triaxial shape of the Milky Way's dark matter halo. We also derive low-resolution spectroscopic abundances along this stretch of the Sgr stream, and explore the stream metallicity gradient reported by Chou et al. (2007, ApJ,670,346). Majewski et al. (2006, ApJL,627,25) showed that because the Sgr debris plane is nearly coincident with the Galactic X-Z Cartesian plane, proper motions in the portion of the Sgr trailing tail in our study almost entirely reflect the solar motion, and can be used to make a direct measurement of the rotation speed at the Solar circle (the "Local Standard of Rest") almost completely independent of the Sun's distance from the Galactic center. Here, we report our derived constraints on the solar motion from absolute proper motions of Sgr debris in our SA fields.

  14. The Southeast Stream Quality Assessment

    USGS Publications Warehouse

    Van Metre, Peter C.; Journey, Celeste

    2014-01-01

    In 2014, the U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) is assessing stream quality across the Piedmont and southern Appalachian Mountains in the southeastern United States. The goal of the Southeast Stream Quality Assessment (SESQA) is to characterize multiple water-quality factors that are stressors to aquatic life—contaminants, nutrients, sediment, and streamflow alteration—and the relation of these stressors to ecological conditions in streams throughout the region. Findings will provide communities and policymakers with information on which human and environmental factors are the most critical in controlling stream quality and, thus, provide insights about possible approaches to protect or improve stream quality. The SESQA study will be the second regional study by the NAWQA program, and it will be of similar design and scope as the Midwest Stream Quality Assessment conducted in 2013 (Van Metre and others, 2012).

  15. The California stream quality assessment

    USGS Publications Warehouse

    Van Metre, Peter C.; Egler, Amanda L.; May, Jason T.

    2017-03-06

    In 2017, the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) project is assessing stream quality in coastal California, United States. The USGS California Stream Quality Assessment (CSQA) will sample streams over most of the Central California Foothills and Coastal Mountains ecoregion (modified from Griffith and others, 2016), where rapid urban growth and intensive agriculture in the larger river valleys are raising concerns that stream health is being degraded. Findings will provide the public and policy-makers with information regarding which human and natural factors are the most critical in affecting stream quality and, thus, provide insights about possible approaches to protect the health of streams in the region.

  16. The Personal Motion Platform

    NASA Technical Reports Server (NTRS)

    Park, Brian Vandellyn

    1993-01-01

    The Neutral Body Posture experienced in microgravity creates a biomechanical equilibrium by enabling the internal forces within the body to find their own balance. A patented reclining chair based on this posture provides a minimal stress environment for interfacing with computer systems for extended periods. When the chair is mounted on a 3 or 6 axis motion platform, a generic motion simulator for simulated digital environments is created. The Personal Motion Platform provides motional feedback to the occupant in synchronization with their movements inside the digital world which enhances the simulation experience. Existing HMD based simulation systems can be integrated to the turnkey system. Future developments are discussed.

  17. Measurement of visual motion

    SciTech Connect

    Hildreth, E.C.

    1984-01-01

    This book examines the measurement of visual motion and the use of relative movement to locate the boundaries of physical objects in the environment. It investigates the nature of the computations that are necessary to perform this analysis by any vision system, biological or artificial. Contents: Introduction. Background. Computation of the Velocity Field. An Algorithm to Compute the Velocity Field. The Computation of Motion Discontinuities. Perceptual Studies of Motion Measurement. The Psychophysics of Discontinuity Detection. Neurophysiological Studies of Motion. Summary and Conclusions. References. Author and Subject Indexes.

  18. Stream Lifetimes Against Planetary Encounters

    NASA Technical Reports Server (NTRS)

    Valsecchi, G. B.; Lega, E.; Froeschle, Cl.

    2011-01-01

    We study, both analytically and numerically, the perturbation induced by an encounter with a planet on a meteoroid stream. Our analytical tool is the extension of pik s theory of close encounters, that we apply to streams described by geocentric variables. The resulting formulae are used to compute the rate at which a stream is dispersed by planetary encounters into the sporadic background. We have verified the accuracy of the analytical model using a numerical test.

  19. Stream salamanders as indicators of stream quality in Maryland, USA

    USGS Publications Warehouse

    Southerland, M.T.; Jung, R.E.; Baxter, D.P.; Chellman, I.C.; Mercurio, G.; Volstad, J.H.

    2004-01-01

    Biological indicators are critical to the protection of small, headwater streams and the ecological values they provide. Maryland and other state monitoring programs have determined that fish indicators are ineffective in small streams, where stream salamanders may replace fish as top predators. Because of their life history, physiology, abundance, and ubiquity, stream salamanders are likely representative of biological integrity in these streams. The goal of this study was to determine whether stream salamanders are effective indicators of ecological conditions across biogeographic regions and gradients of human disturbance. During the summers of 2001 and 2002, we intensively surveyed for stream salamanders at 76 stream sites located west of the Maryland Coastal Plain, sites also monitored by the Maryland Biological Stream Survey (MBSS) and City of Gaithersburg. We found 1,584 stream salamanders, including all eight species known in Maryland, using two 15 ? 2 m transects and two 4 m2 quadrats that spanned both stream bank and channel. We performed removal sampling on transects to estimate salamander species detection probabilities, which ranged from 0.67-0.85. Stepwise regressions identified 15 of 52 non-salamander variables, representing water quality, physical habitat, land use, and biological conditions, which best predicted salamander metrics. Indicator development involved (1) identifying reference (non-degraded) and degraded sites (using percent forest, shading, riparian buffer width, aesthetic rating, and benthic macroinvertebrate and fish indices of biotic integrity); (2) testing 12 candidate salamander metrics (representing species richness and composition, abundance, species tolerance, and reproductive function) for their ability to distinguish reference from degraded sites; and (3) combining metrics into an index that effectively discriminated sites according to known stream conditions. Final indices for Highlands, Piedmont, and Non-Coastal Plain

  20. The Phoenix Stream: A Cold Stream in the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Balbinot, E.; Yanny, B.; Li, T. S.; Santiago, B.; Marshall, J. L.; Finley, D. A.; Pieres, A.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; March, M.; Martini, P.; Miquel, R.; Nichol, R. C.; Ogando, R.; Romer, A. K.; Sanchez, E.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Tucker, D.; Walker, A. R.; DES Collaboration

    2016-03-01

    We report the discovery of a stellar stream in the Dark Energy Survey Year 1 (Y1A1) data. The discovery was made through simple color-magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color-magnitude space, we find that a stellar population with age τ = 11.5 ± 0.5 Gyr and [Fe/H] < -1.6, located 17.5 ± 0.9 kpc from the Sun, gives an adequate description of the stream stellar population. The stream is detected over an extension of 8.°1 (2.5 kpc) and has a width of ˜54 pc assuming a Gaussian profile, indicating that a globular cluster (GC) is a probable progenitor. There is no known GC within 5 kpc that is compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities (ODs) along the stream, however, no obvious counterpart-bound stellar system is visible in the coadded images. We also find ODs along the stream that appear to be symmetrically distributed—consistent with the epicyclic OD scenario for the formation of cold streams—as well as a misalignment between the northern and southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe OD.

  1. Analyzing indicators of stream health for Minnesota streams

    USGS Publications Warehouse

    Singh, U.; Kocian, M.; Wilson, B.; Bolton, A.; Nieber, J.; Vondracek, B.; Perry, J.; Magner, J.

    2005-01-01

    Recent research has emphasized the importance of using physical, chemical, and biological indicators of stream health for diagnosing impaired watersheds and their receiving water bodies. A multidisciplinary team at the University of Minnesota is carrying out research to develop a stream classification system for Total Maximum Daily Load (TMDL) assessment. Funding for this research is provided by the United States Environmental Protection Agency and the Minnesota Pollution Control Agency. One objective of the research study involves investigating the relationships between indicators of stream health and localized stream characteristics. Measured data from Minnesota streams collected by various government and non-government agencies and research institutions have been obtained for the research study. Innovative Geographic Information Systems tools developed by the Environmental Science Research Institute and the University of Texas are being utilized to combine and organize the data. Simple linear relationships between index of biological integrity (IBI) and channel slope, two-year stream flow, and drainage area are presented for the Redwood River and the Snake River Basins. Results suggest that more rigorous techniques are needed to successfully capture trends in IBI scores. Additional analyses will be done using multiple regression, principal component analysis, and clustering techniques. Uncovering key independent variables and understanding how they fit together to influence stream health are critical in the development of a stream classification for TMDL assessment.

  2. ASSESSING STREAM BED STABILITY AND EXCESS SEDIMENTATION IN MOUNTAIN STREAMS

    EPA Science Inventory

    Land use and resource exploitation in headwaters catchments?such as logging, mining, and road building?often increase sediment supply to streams, potentially causing excess sedimentation. Decreases in mean substrate size and increases in fine stream bed sediments can lead to inc...

  3. Emittance Growth in Intense Non-Circular Beams

    NASA Astrophysics Data System (ADS)

    Anderson, O. A.

    1997-05-01

    The electrostatic energy of intense beams in linear uniform focusing channels is minimized when the initial beam configuration is both uniform and round.(In the case of quadrupole focusing, this means round on the average.) Deviations from either uniformity or roundness produce free energy and emittance growth. Over the past 25 years, the consequences of beam nonuniformity have been thoroughly investigated for the case of round beams. Recently, there has been interest in more complex beam configurations such as those that occur in Heavy Ion Fusion (HIF) combiners or splitters. We discuss free energy and emittance growth for a variety of cases: (a) square beams, (b) hexagonal beams, (c) beams bounded by a quadrant or sextant of a circle, (d) rectangular beams, (e) elliptical beams, (f) pairs of beamlets, and (g) arrays of many beamlets. Cases (a) and (b) are approximations for large arrays of beamlets as proposed for HIF combiners or for negative-ion sources. Beam splitting, suggested for a particular HIF final focus scheme, leads to (c). The large emittance growth in cases (d)-(f), calculated by a new method,(O.A. Anderson, Proceedings of EPAC 96 conference.) illustrates the importance of maintaining symmetry. Practical examples are given for several cases.

  4. Flow in tubes of non-circular cross-sections

    NASA Astrophysics Data System (ADS)

    Quadir, Raushan Ara

    Laminar, viscous, incompressible flow in tubes of noncircular cross sections is investigated. The specific aims of the investigation are (1) to look at the problems of both developing flow and fully developed flow, (2) to consider noncircular cross sections in a more systematic manner than has been done in the past, and (3) to develop a relatively simple finite element technique for producing accurate numerical solutions of flow in tubes of fairly arbitrary cross sections. Fully developed flow in tubes is governed by a Poisson type equation for the mainstream velocity. Both analytical and numerical solutions are considered. The cross sections studied include elliptic and rectangular cross sections of different aspect ratios, some triangular cross sections, and a series of crescent-shaped cross sections. The physical characteristics of the flow are examined in a systematic manner in order to determine how these characteristics are affected by certain geometrical features of the cross section. Solutions fall into three basic categories depending on the shape of the cross section. In the first category, which includes circular and elliptic cross sections, solutions are possible in closed form. In the second, including rectangular and some triangular cross sections, solutions are in the form of infinite series. In the third, including cross sections of more complicated or irregular shapes, only numerical solutions are possible. Results of calculations of velocity profiles, flow rate, pumping power, and friction factor are presented in a way which can be useful for engineering applications. In numerical studies of both developing and fully developed flow finite element techniques are used. Results are obtained for tubes of rectangular and elliptic cross sections of different aspect ratios, for tubes of crescent-shaped cross sections, and a tube whose cross section is an oval of Cassini. For fully developed flow, results are compared with the corresponding exact solutions, where available. For rectangular and elliptic cross sections results are also compared with those obtained by using a commercial package (FIDAP). For developing flow, finite element results are compared with corresponding theoretical and experimental results from previous work, where available.

  5. Motion compensator for holographic motion picture camera

    NASA Technical Reports Server (NTRS)

    Kurtz, R. L.

    1973-01-01

    When reference beam strikes target it undergoes Doppler shift dependent upon target velocity. To compensate, object beam is first reflected from rotating cylinder that revolves in direction opposite to target but at same speed. When beam strikes target it is returned to original frequency and is in phase with reference beam. Alternatively this motion compensator may act on reference beam.

  6. Human impacts to mountain streams

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen

    2006-09-01

    Mountain streams are here defined as channel networks within mountainous regions of the world. This definition encompasses tremendous diversity of physical and biological conditions, as well as history of land use. Human effects on mountain streams may result from activities undertaken within the stream channel that directly alter channel geometry, the dynamics of water and sediment movement, contaminants in the stream, or aquatic and riparian communities. Examples include channelization, construction of grade-control structures or check dams, removal of beavers, and placer mining. Human effects can also result from activities within the watershed that indirectly affect streams by altering the movement of water, sediment, and contaminants into the channel. Deforestation, cropping, grazing, land drainage, and urbanization are among the land uses that indirectly alter stream processes. An overview of the relative intensity of human impacts to mountain streams is provided by a table summarizing human effects on each of the major mountainous regions with respect to five categories: flow regulation, biotic integrity, water pollution, channel alteration, and land use. This table indicates that very few mountains have streams not at least moderately affected by land use. The least affected mountainous regions are those at very high or very low latitudes, although our scientific ignorance of conditions in low-latitude mountains in particular means that streams in these mountains might be more altered than is widely recognized. Four case studies from northern Sweden (arctic region), Colorado Front Range (semiarid temperate region), Swiss Alps (humid temperate region), and Papua New Guinea (humid tropics) are also used to explore in detail the history and effects on rivers of human activities in mountainous regions. The overview and case studies indicate that mountain streams must be managed with particular attention to upstream/downstream connections, hillslope

  7. Objects in Motion

    ERIC Educational Resources Information Center

    Ashbrook, Peggy

    2008-01-01

    Objects in motion attract children. The following activity helps children explore the motion of bodies riding in a vehicle and safely demonstrates the answer to their questions, "Why do I need a seatbelt?" Children will enjoy moving the cup around, even if all they "see" is a cup rather than understanding it represents a car. They will understand…

  8. Teaching Projectile Motion

    ERIC Educational Resources Information Center

    Summers, M. K.

    1977-01-01

    Described is a novel approach to the teaching of projectile motion of sixth form level. Students are asked to use an analogue circuit to observe projectile motion and to graph the experimental results. Using knowledge of basic dynamics, students are asked to explain the shape of the curves theoretically. (Author/MA)

  9. Making Sense of Motion

    ERIC Educational Resources Information Center

    King, Kenneth

    2005-01-01

    When watching a small child with a toy car, it is seen that interest in motion comes early. Children often suggest speed through sounds such as "RRRrrrRRRooooommMMMmmmm" as the toy car is made to speed up, slow down, or accelerate through a turn. Older children start to consider force and motion studies in more detail, and experiences in school…

  10. Aristotle, Motion, and Rhetoric.

    ERIC Educational Resources Information Center

    Sutton, Jane

    Aristotle rejects a world vision of changing reality as neither useful nor beneficial to human life, and instead he reaffirms both change and eternal reality, fuses motion and rest, and ends up with "well-behaved" changes. This concept of motion is foundational to his world view, and from it emerges his theory of knowledge, philosophy of…

  11. Body Motion and Graphing.

    ERIC Educational Resources Information Center

    Nemirovsky, Ricardo; Tierney, Cornelia; Wright, Tracy

    1998-01-01

    Analyzed two children's use of a computer-based motion detector to make sense of symbolic expressions (Cartesian graphs). Found three themes: (1) tool perspectives, efforts to understand graphical responses to body motion; (2) fusion, emergent ways of talking and behaving that merge symbols and referents; and (3) graphical spaces, when changing…

  12. Naive Conceptions of Motion.

    ERIC Educational Resources Information Center

    McCloskey, Michael

    Two experiments were conducted to characterize the system of beliefs that make up the naive impetus theory of motion and to determine what effects physics instruction has on students' conceptions of motion. Thirteen college students were asked to solve several quantitative problems and were interviewed about their answers in the first experiment.…

  13. Measuring mandibular motions

    NASA Technical Reports Server (NTRS)

    Dimeff, J.; Rositano, S.; Taylor, R. C.

    1977-01-01

    Mandibular motion along three axes is measured by three motion transducers on floating yoke that rests against mandible. System includes electronics to provide variety of outputs for data display and processing. Head frame is strapped to test subject's skull to provide fixed point of reference for transducers.

  14. Object motion analysis study

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The use of optical data processing (ODP) techniques for motion analysis in two-dimensional imagery was studied. The basic feasibility of this approach was demonstrated, but inconsistent performance of the photoplastic used for recording spatial filters prevented totally automatic operation. Promising solutions to the problems encountered are discussed, and it is concluded that ODP techniques could be quite useful for motion analysis.

  15. A Motion-from-Form Mechanism Contributes to Extracting Pattern Motion from Plaids

    PubMed Central

    Optican, Lance M.; Cumming, Bruce G.

    2016-01-01

    Since the discovery of neurons selective for pattern motion direction in primate middle temporal area MT (Albright, 1984; Movshon et al., 1985), the neural computation of this signal has been the subject of intense study. The bulk of this work has explored responses to plaids obtained by summing two drifting sinusoidal gratings. Unfortunately, with these stimuli, many different mechanisms are similarly effective at extracting pattern motion. We devised a new set of stimuli, obtained by summing two random line stimuli with different orientations. This allowed several novel manipulations, including generating plaids that do not contain rigid 2D motion. Importantly, these stimuli do not engage most of the previously proposed mechanisms. We then recorded the ocular following responses that such stimuli induce in human subjects. We found that pattern motion is computed even with stimuli that do not cohere perceptually, including those without rigid motion, and even when the two gratings are presented separately to the two eyes. Moderate temporal and/or spatial separation of the gratings impairs the computation. We show that, of the models proposed so far, only those based on the intersection-of-constraints rule, embedding a motion-from-form mechanism (in which orientation signals are used in the computation of motion direction signals), can account for our results. At least for the eye movements reported here, a motion-from-form mechanism is thus involved in one of the most basic functions of the visual motion system: extracting motion direction from complex scenes. SIGNIFICANCE STATEMENT Anatomical considerations led to the proposal that visual function is organized in separate processing streams: one (ventral) devoted to form and one (dorsal) devoted to motion. Several experimental results have challenged this view, arguing in favor of a more integrated view of visual processing. Here we add to this body of work, supporting a role for form information even in a

  16. Stochastic ground motion simulation

    USGS Publications Warehouse

    Rezaeian, Sanaz; Xiaodan, Sun; Beer, Michael; Kougioumtzoglou, Ioannis A.; Patelli, Edoardo; Siu-Kui Au, Ivan

    2014-01-01

    Strong earthquake ground motion records are fundamental in engineering applications. Ground motion time series are used in response-history dynamic analysis of structural or geotechnical systems. In such analysis, the validity of predicted responses depends on the validity of the input excitations. Ground motion records are also used to develop ground motion prediction equations(GMPEs) for intensity measures such as spectral accelerations that are used in response-spectrum dynamic analysis. Despite the thousands of available strong ground motion records, there remains a shortage of records for large-magnitude earthquakes at short distances or in specific regions, as well as records that sample specific combinations of source, path, and site characteristics.

  17. We All Stream for Video

    ERIC Educational Resources Information Center

    Technology & Learning, 2008

    2008-01-01

    More than ever, teachers are using digital video to enhance their lessons. In fact, the number of schools using video streaming increased from 30 percent to 45 percent between 2004 and 2006, according to Market Data Retrieval. Why the popularity? For starters, video-streaming products are easy to use. They allow teachers to punctuate lessons with…

  18. Industrial-Strength Streaming Video.

    ERIC Educational Resources Information Center

    Avgerakis, George; Waring, Becky

    1997-01-01

    Corporate training, financial services, entertainment, and education are among the top applications for streaming video servers, which send video to the desktop without downloading the whole file to the hard disk, saving time and eliminating copyrights questions. Examines streaming video technology, lists ten tips for better net video, and ranks…

  19. Save Our Streams and Waterways.

    ERIC Educational Resources Information Center

    Indiana State Dept. of Education, Indianapolis. Center for School Improvement and Performance.

    Protection of existing water supplies is critical to ensuring good health for people and animals alike. This program is aligned with the Izaak Walton League of American's Save Our Streams program which is based on the concept that students can greatly improve the quality of a nearby stream, pond, or river by regular visits and monitoring. The…

  20. Motion sickness in migraine sufferers.

    PubMed

    Marcus, Dawn A; Furman, Joseph M; Balaban, Carey D

    2005-12-01

    Motion sickness commonly occurs after exposure to actual motion, such as car or amusement park rides, or virtual motion, such as panoramic movies. Motion sickness symptoms may be disabling, significantly limiting business, travel and leisure activities. Motion sickness occurs in approximately 50% of migraine sufferers. Understanding motion sickness in migraine patients may improve understanding of the physiology of both conditions. Recent literature suggests important relationships between the trigeminal system and vestibular nuclei that may have implications for both motion sickness and migraine. Studies demonstrating an important relationship between serotonin receptors and motion sickness susceptibility in both rodents and humans suggest possible new motion sickness prevention therapies.

  1. Dynamical modelling of meteoroid streams

    NASA Astrophysics Data System (ADS)

    Clark, D. L.; Wiegert, P. A.

    2014-07-01

    Accurate simulations of meteoroid streams permit the prediction of stream interaction with Earth, and provide a measure of risk to Earth satellites and interplanetary spacecraft. Current cometary ejecta and meteoroid stream models have been somewhat successful in predicting some stream observations, but have required significant assumptions and simplifications. Extending on the approach of Vaubaillon et al. 2005, we model dust ejection from the cometary nucleus, and generate sample particles representing bins of distinct dynamical evolution-regulating characteristics (size, density, direction, albedo). Ephemerides of the sample particles are integrated and recorded for later assignment of weights based on model parameter changes. To assist in model analysis we are developing interactive software to permit the "turning of knobs" of model parameters, allowing for near-real-time 3D visualization of resulting stream structure. Using the tool, we will revisit prior assumptions made, and will observe the impact of introducing non-uniform and time-variant cometary surface attributes and processes.

  2. Stream Clustering of Growing Objects

    NASA Astrophysics Data System (ADS)

    Siddiqui, Zaigham Faraz; Spiliopoulou, Myra

    We study incremental clustering of objects that grow and accumulate over time. The objects come from a multi-table stream e.g. streams of Customer and Transaction. As the Transactions stream accumulates, the Customers’ profiles grow. First, we use an incremental propositionalisation to convert the multi-table stream into a single-table stream upon which we apply clustering. For this purpose, we develop an online version of K-Means algorithm that can handle these swelling objects and any new objects that arrive. The algorithm also monitors the quality of the model and performs re-clustering when it deteriorates. We evaluate our method on the PKDD Challenge 1999 dataset.

  3. FireHose Streaming Benchmarks

    SciTech Connect

    Karl Anderson, Steve Plimpton

    2015-01-27

    The FireHose Streaming Benchmarks are a suite of stream-processing benchmarks defined to enable comparison of streaming software and hardware, both quantitatively vis-a-vis the rate at which they can process data, and qualitatively by judging the effort involved to implement and run the benchmarks. Each benchmark has two parts. The first is a generator which produces and outputs datums at a high rate in a specific format. The second is an analytic which reads the stream of datums and is required to perform a well-defined calculation on the collection of datums, typically to find anomalous datums that have been created in the stream by the generator. The FireHose suite provides code for the generators, sample code for the analytics (which users are free to re-implement in their own custom frameworks), and a precise definition of each benchmark calculation.

  4. The role of penetrating gas streams in setting the dynamical state of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Zinger, E.; Dekel, A.; Birnboim, Y.; Kravtsov, A.; Nagai, D.

    2016-09-01

    We utilize cosmological simulations of 16 galaxy clusters at redshifts z = 0 and z = 0.6 to study the effect of inflowing streams on the properties of the X-ray emitting intracluster medium. We find that the mass accretion occurs predominantly along streams that originate from the cosmic web and consist of heated gas. Clusters that are unrelaxed in terms of their X-ray morphology are characterized by higher mass inflow rates and deeper penetration of the streams, typically into the inner third of the virial radius. The penetrating streams generate elevated random motions, bulk flows and cold fronts. The degree of penetration of the streams may change over time such that clusters can switch from being unrelaxed to relaxed over a time-scale of several giga years.

  5. What a Tangled Web We Weave: Hermus as the Northern Extension of the Phoenix Stream

    NASA Astrophysics Data System (ADS)

    Grillmair, Carl J.; Carlberg, Raymond G.

    2016-04-01

    We investigate whether the recently discovered Phoenix stream may be part of a much longer stream that includes the previously discovered Hermus stream. Using a simple model of the Galaxy with a disk, bulge, and a spherical dark matter halo, we show that a nearly circular orbit, highly inclined with respect to the disk, can be found that fits the positions, orientations, and distances of both streams. While the two streams are somewhat misaligned in the sense that they do not occupy the same plane, nodal precession due to the Milky Way disk potential naturally brings the orbit into line with each stream in the course of half an orbit. We consequently consider a common origin for the two streams as plausible. Based on our best-fitting orbit, we make predictions for the positions, distances, radial velocities, and proper motions along each stream. If our hypothesis is borne out by measurements, then at ≈183° (≈235° with respect to the Galactic center) and ≈76 kpc in length, Phoenix-Hermus would become the longest cold stream yet found. This would make it a particularly valuable new probe of the shape and mass of the Galactic halo out to ≈20 kpc.

  6. Impact of baryonic streaming velocities on the formation of supermassive black holes via direct collapse

    NASA Astrophysics Data System (ADS)

    Latif, M. A.; Niemeyer, J. C.; Schleicher, D. R. G.

    2014-06-01

    Baryonic streaming motions produced prior to the epoch of recombination became supersonic during the cosmic dark ages. Various studies suggest that such streaming velocities change the halo statistics and also influence the formation of Population III stars. In this study, we aim to explore the impact of streaming velocities on the formation of supermassive black holes at z>10 via the direct collapse scenario. To accomplish this goal, we perform cosmological large eddy simulations for two haloes of a few times 107M⊙ with initial streaming velocities of 3, 6 and 9 km s-1. These massive primordial haloes illuminated by the strong Lyman-Werner flux are the potential cradles for the formation of direct collapse seed black holes. To study the evolution for longer times, we employ sink particles and track the accretion for 10 000 years. Our findings show that higher streaming velocities increase the circular velocities from about 14 to 16 km s-1. They also delay the collapse of haloes for a few million years, but do not have any significant impact on the halo properties such as turbulent energy, radial velocity, density and accretion rates. Sink particles of about ˜105M⊙ are formed at the end of our simulations and no clear distribution of sink masses is observed in the presence of streaming motions. It is further found that the impact of streaming velocities is less severe in massive haloes compared to the minihaloes as reported in the previous studies.

  7. Visualizing motion in video

    NASA Astrophysics Data System (ADS)

    Brown, Lisa M.; Crayne, Susan

    2000-05-01

    In this paper, we present a visualization system and method for measuring, inspecting and analyzing motion in video. Starting from a simple motion video, the system creates a still image representation which we call a digital strobe photograph. Similar to visualization techniques used in conventional film photography to capture high-speed motion using strobe lamps or very fast shutters, and to capture time-lapse motion where the shutter is left open, this methodology creates a single image showing the motion of one or a small number of objects over time. Based on digital background subtraction, we assume that the background is stationary or at most slowing changing and that the camera position is fixed. The method is capable of displaying the motion based on a parameter indicating the time step between successive movements. It can also overcome problems of visualizing movement that is obscured by previous movements. The method is used in an educational software tool for children to measure and analyze various motions. Examples are given using simple physical objects such as balls and pendulums, astronomical events such as the path of the stars around the north pole at night, or the different types of locomotion used by snakes.

  8. Motion Recognition and Modifying Motion Generation for Imitation Robot Based on Motion Knowledge Formation

    NASA Astrophysics Data System (ADS)

    Okuzawa, Yuki; Kato, Shohei; Kanoh, Masayoshi; Itoh, Hidenori

    A knowledge-based approach to imitation learning of motion generation for humanoid robots and an imitative motion generation system based on motion knowledge learning and modification are described. The system has three parts: recognizing, learning, and modifying parts. The first part recognizes an instructed motion distinguishing it from the motion knowledge database by the continuous hidden markov model. When the motion is recognized as being unfamiliar, the second part learns it using locally weighted regression and acquires a knowledge of the motion. When a robot recognizes the instructed motion as familiar or judges that its acquired knowledge is applicable to the motion generation, the third part imitates the instructed motion by modifying a learned motion. This paper reports some performance results: the motion imitation of several radio gymnastics motions.

  9. Inflation and cyclotron motion

    NASA Astrophysics Data System (ADS)

    Greensite, Jeff

    2017-01-01

    We consider, in the context of a braneworld cosmology, the motion of the Universe coupled to a four-form gauge field, with constant field strength, defined in higher dimensions. It is found, under rather general initial conditions, that in this situation there is a period of exponential inflation combined with cyclotron motion in the inflaton field space. The main effect of the cyclotron motion is that slow roll conditions on the inflaton potential, which are typically necessary for exponential inflation, can be evaded. There are Landau levels associated with the four-form gauge field, and these correspond to quantum excitations of the inflaton field satisfying unconventional dispersion relations.

  10. Generalized compliant motion primitive

    NASA Astrophysics Data System (ADS)

    Backes, Paul G.

    1994-08-01

    This invention relates to a general primitive for controlling a telerobot with a set of input parameters. The primitive includes a trajectory generator; a teleoperation sensor; a joint limit generator; a force setpoint generator; a dither function generator, which produces telerobot motion inputs in a common coordinate frame for simultaneous combination in sensor summers. Virtual return spring motion input is provided by a restoration spring subsystem. The novel features of this invention include use of a single general motion primitive at a remote site to permit the shared and supervisory control of the robot manipulator to perform tasks via a remotely transferred input parameter set.

  11. Electronic Eye: Streaming Video On-Demand.

    ERIC Educational Resources Information Center

    Meulen, Kathleen

    2002-01-01

    Discusses the use of on-demand streaming video in school libraries. Explains how streaming works, considers advantages and technical issues, and describes products from three companies that are pioneering streaming in the educational video market. (LRW)

  12. An application of Galactic parallax: the distance to the tidal stream GD-1

    NASA Astrophysics Data System (ADS)

    Eyre, Andy

    2010-04-01

    We assess the practicality of computing the distance to stellar streams in our Galaxy, using the method of Galactic parallax suggested by Eyre & Binney. We find that the uncertainty in Galactic parallax is dependent upon the specific geometry of the problem in question. In the case of the tidal stream GD-1, the problem geometry indicates that available proper-motion data, with individual accuracy ~4masyr-1, should allow estimation of its distance with about 50 per cent uncertainty. Proper motions accurate to ~1masyr-1, which are expected from the forthcoming Pan-STARRS PS-1 survey, will allow estimation of its distance to about 10 per cent uncertainty. Proper motions from the future Large Synoptic Survey Telescope (LSST) and Gaia projects will be more accurate still, and will allow the parallax for a stream 30 kpc distant to be measured with ~14 per cent uncertainty. We demonstrate the feasibility of the method and show that our uncertainty estimates are accurate by computing Galactic parallax using simulated data for the GD-1 stream. We also apply the method to actual data for the GD-1 stream, published by Koposov, Rix & Hogg. With the exception of one datum, the distances estimated using Galactic parallax match photometric estimates with less than 1 kpc discrepancy. The scatter in the distances recovered using Galactic parallax is very low, suggesting that the proper-motion uncertainty reported by Koposov et al. is in fact overestimated. We conclude that the GD-1 stream is (8 +/- 1)kpc distant, on a retrograde orbit inclined 37° to the plane, and that the visible portion of the stream is likely to be near pericentre.

  13. WADEABLE STREAMS ASSESSMENT | Science Inventory ...

    EPA Pesticide Factsheets

    This Wadeable Streams Assessment (WSA) provides the first statistically defensible summary of the condition of the nation’s streams and small rivers, which are so integrally tied to our history. This report brings the results of this ground-breaking study to the American public.This assessment encompasses the wadeable streams and rivers that account for a vast majority of the length of flowing waters in the United States. To perform this assessment, EPA, the states, and tribes collected chemical, physical, and biological data at more 1,392 wadeable perennial stream locations to determine the biological condition of these waters and the most important factors affecting their water quality. Teams collected samples at sites chosen using an innovative statistical design to ensure representative results. The results of this analysis provide a clear assessment of the biological quality of wadeable, perennial streams and rivers across the country, within each of three major climatic and landform regions, and nine ecological regions. Information provided in this report fills an important gap in meeting the requirements of the CWA. The purpose of this assessment is fourfold: 1. Report on the ecological condition of all wadeable, perennial streams and rivers within the conterminous United States. (Pilot projects are underway in Alaska and Hawaii.) 2. Describe the biological condition of these systems using direct measures of aquatic life. Assessments of stream

  14. The Stream-Catchment (StreamCat) Dataset

    EPA Science Inventory

    Stream environments reflect, in part, the hydrologic integration of upstream landscapes. Characterizing upstream landscape features is critical for effectively understanding, managing, and conserving riverine ecosystems. However, watershed delineation is a major challenge if hund...

  15. CodedStream: live media streaming with overlay coded multicast

    NASA Astrophysics Data System (ADS)

    Guo, Jiang; Zhu, Ying; Li, Baochun

    2003-12-01

    Multicasting is a natural paradigm for streaming live multimedia to multiple end receivers. Since IP multicast is not widely deployed, many application-layer multicast protocols have been proposed. However, all of these schemes focus on the construction of multicast trees, where a relatively small number of links carry the multicast streaming load, while the capacity of most of the other links in the overlay network remain unused. In this paper, we propose CodedStream, a high-bandwidth live media distribution system based on end-system overlay multicast. In CodedStream, we construct a k-redundant multicast graph (a directed acyclic graph) as the multicast topology, on which network coding is applied to work around bottlenecks. Simulation results have shown that the combination of k-redundant multicast graph and network coding may indeed bring significant benefits with respect to improving the quality of live media at the end receivers.

  16. Projectile Motion with Mathematica.

    ERIC Educational Resources Information Center

    de Alwis, Tilak

    2000-01-01

    Describes how to use the computer algebra system (CAS) Mathematica to analyze projectile motion with and without air resistance. These experiments result in several conjectures leading to theorems. (Contains 17 references.) (Author/ASK)

  17. Projectile Motion Details.

    ERIC Educational Resources Information Center

    Schnick, Jeffrey W.

    1994-01-01

    Presents an exercise that attempts to correct for the common discrepancies between theoretical and experimental predictions concerning projectile motion using a spring-loaded projectile ball launcher. Includes common correction factors for student use. (MVL)

  18. Toying with Motion.

    ERIC Educational Resources Information Center

    Galus, Pamela J.

    2002-01-01

    Presents a variety of activities that support the development of an understanding of Newton's laws of motion. Activities use toy cars, mobile roads, and a seat-of-nails. Includes a scoring rubric. (DDR)

  19. Vision and Motion Pictures.

    ERIC Educational Resources Information Center

    Grambo, Gregory

    1998-01-01

    Presents activities on persistence of vision that involve students in a hands-on approach to the study of early methods of creating motion pictures. Students construct flip books, a Zoetrope, and an early movie machine. (DDR)

  20. Motion Sickness: First Aid

    MedlinePlus

    ... soon as the motion stops. The more you travel, the more easily you'll adjust to being ... at least 30 to 60 minutes before you travel. Expect drowsiness as a side effect. Consider scopolamine ( ...

  1. A Projectile Motion Bullseye.

    ERIC Educational Resources Information Center

    Lamb, William G.

    1985-01-01

    Explains a projectile motion experiment involving a bow and arrow. Procedures to measure "muzzle" velocity, bow elastic potential energy, range, flight time, wind resistance, and masses are considered. (DH)

  2. Motion Alters Color Appearance

    PubMed Central

    Hong, Sang-Wook; Kang, Min-Suk

    2016-01-01

    Chromatic induction compellingly demonstrates that chromatic context as well as spectral lights reflected from an object determines its color appearance. Here, we show that when one colored object moves around an identical stationary object, the perceived saturation of the stationary object decreases dramatically whereas the saturation of the moving object increases. These color appearance shifts in the opposite directions suggest that normalization induced by the object’s motion may mediate the shift in color appearance. We ruled out other plausible alternatives such as local adaptation, attention, and transient neural responses that could explain the color shift without assuming interaction between color and motion processing. These results demonstrate that the motion of an object affects both its own color appearance and the color appearance of a nearby object, suggesting a tight coupling between color and motion processing. PMID:27824098

  3. Explanations of Superluminal Motion

    NASA Astrophysics Data System (ADS)

    Scheuer, P. A. G.

    Recent developments in models of core-jet sources with apparent superluminal motions are reviewed. Emphasis is given to new versions of the so-called "Christmas tree" model and the relativistic beaming model.

  4. Motion perception correlates with volitional but not reflexive eye movements.

    PubMed

    Price, N S C; Blum, J

    2014-09-26

    Visually-driven actions and perception are traditionally ascribed to the dorsal and ventral visual streams of the cortical processing hierarchy. However, motion perception and the control of tracking eye movements both depend on sensory motion analysis by neurons in the dorsal stream, suggesting that the same sensory circuits may underlie both action and perception. Previous studies have suggested that multiple sensory modules may be responsible for the perception of low- and high-level motion, or the detection versus identification of motion direction. However, it remains unclear whether the sensory processing systems that contribute to direction perception and the control of eye movements have the same neuronal constraints. To address this, we examined inter-individual variability across 36 observers, using two tasks that simultaneously assessed the precision of eye movements and direction perception: in the smooth pursuit task, observers volitionally tracked a small moving target and reported its direction; in the ocular following task, observers reflexively tracked a large moving stimulus and reported its direction. We determined perceptual-oculomotor correlations across observers, defined as the correlation between each observer's mean perceptual precision and mean oculomotor precision. Across observers, we found that: (i) mean perceptual precision was correlated between the two tasks; (ii) mean oculomotor precision was correlated between the tasks, and (iii) oculomotor and perceptual precision were correlated for volitional smooth pursuit, but not reflexive ocular following. Collectively, these results demonstrate that sensory circuits with common neuronal constraints subserve motion perception and volitional, but not reflexive eye movements.

  5. Experimental and numerical investigation of Acoustic streaming (Eckart streaming)

    NASA Astrophysics Data System (ADS)

    Dridi, Walid; Botton, Valery; Henry, Daniel; Ben Hadid, Hamda

    The application of sound waves in the bulk of a fluid can generate steady or quasi-steady flows reffered to as Acoustic streaming flows. We can distinguish two kind of acoustic streaming: The Rayleigh Streaming is generated when a standing acoustic waves interfere with solid walls to give birth to an acoustic boundary layer. Steady recirculations are then driven out of the boundary layer and can be used in micro-gravity, where the free convection is too weak or absent, to enhance the convective heat or mass transfer and cooling the electronic devises [1]. The second kind is the Eckart streaming, which is a flow generated far from the solid boundaries, it can be used to mix a chemical solutions [2], and to drive a viscous liquids in channels [3-4], in micro-gravity area. Our study focuses on the Eckart streaming configuration, which is investigated both numerical and experimental means. The experimental configuration is restricted to the case of a cylindrical non-heated cavity full of water or of a water+glycerol mixture. At the middle of one side of the cavity, a plane ultrasonic transducer generates a 2MHz wave; an absorber is set at the opposite side of the cavity to avoid any reflections. The velocity field is measured with a standard PIV system. [1] P. Vainshtein, M. Fichman and C. Gutfinger, "Acoustic enhancement of heat transfer between two parallel plates", International Journal of Heat and Mass Transfert, 1995, 38(10), 1893. [2] C. Suri, K. Tekenaka, H. Yanagida, Y. Kojima and K. Koyama, "Chaotic mixing generated by acoustic streaming", Ultrasonics, 2002, 40, 393 [3] O.V. Rudenko and A.A. Sukhorukov, "Nonstationnary Eckart streaming and pumping of liquid in ultrasonic field", Acoustical Physics, 1998, 44, 653. [4] Kenneth D. Frampton, Shawn E. Martin and Keith Minor, "The scaling of acoustic streaming for application in micro-fluidic devices", Applied Acoustics, 2003, 64,681

  6. The motion of bubbles inside drops in containerless processing

    NASA Technical Reports Server (NTRS)

    Shankar, N.; Annamalai, P.; Cole, R.; Subramanian, R. S.

    1982-01-01

    A theoretical model of thermocapillary bubble motion inside a drop, located in a space laboratory, due to an arbitrary axisymmetric temperature distribution on the drop surface was constructed. Typical results for the stream function and temperature fields as well as the migration velocity of the bubble were obtained in the quasistatic limit. The motion of bubbles in a rotating body of liquid was studied experimentally, and an approximate theoretical model was developed. Comparison of the experimental observations of the bubble trajectories and centering times with theoretical predictions lends qualified support to the theory.

  7. Mixing of Supersonic Streams

    NASA Technical Reports Server (NTRS)

    Hawk, C. W.; Landrum, D. B.; Muller, S.; Turner, M.; Parkinson, D.

    1998-01-01

    The Strutjet approach to Rocket Based Combined Cycle (RBCC) propulsion depends upon fuel-rich flows from the rocket nozzles and turbine exhaust products mixing with the ingested air for successful operation in the ramjet and scramjet modes. It is desirable to delay this mixing process in the air-augmented mode of operation present during low speed flight. A model of the Strutjet device has been built and is undergoing test to investigate the mixing of the streams as a function of distance from the Strutjet exit plane during simulated low speed flight conditions. Cold flow testing of a 1/6 scale Strutjet model is underway and nearing completion. Planar Laser Induced Fluorescence (PLIF) diagnostic methods are being employed to observe the mixing of the turbine exhaust gas with the gases from both the primary rockets and the ingested air simulating low speed, air augmented operation of the RBCC. The ratio of the pressure in the turbine exhaust duct to that in the rocket nozzle wall at the point of their intersection is the independent variable in these experiments. Tests were accomplished at values of 1.0, 1.5 and 2.0 for this parameter. Qualitative results illustrate the development of the mixing zone from the exit plane of the model to a distance of about 10 rocket nozzle exit diameters downstream. These data show the mixing to be confined in the vertical plane for all cases, The lateral expansion is more pronounced at a pressure ratio of 1.0 and suggests that mixing with the ingested flow would be likely beginning at a distance of 7 nozzle exit diameters downstream of the nozzle exit plane.

  8. Mixing of Supersonic Streams

    NASA Technical Reports Server (NTRS)

    Hawk, C. W.; Landrum, D. B.; Muller, S.; Turner, M.; Parkinson, D.

    1998-01-01

    The Strutjet approach to Rocket Based Combined Cycle (RBCC) propulsion depends upon fuel-rich flows from the rocket nozzles and turbine exhaust products mixing with the ingested air for successful operation in the ramjet and scramjet modes. It is desirable to delay this mixing process in the air-augmented mode of operation present during low speed flight. A model of the Strutjet device has been built and is undergoing test to investigate the mixing of the streams as a function of distance from the Strutjet exit plane during simulated low speed flight conditions. Cold flow testing of a 1/6 scale Strutjet model is underway and nearing completion. Planar Laser Induced Fluorescence (PLIF) diagnostic methods are being employed to observe the mixing of the turbine exhaust gas with the gases from both the primary rockets and the ingested air simulating low speed, air augmented operation of the RBCC. The ratio of the pressure in the turbine exhaust duct to that in the rocket nozzle wall at the point of their intersection is the independent variable in these experiments. Tests were accomplished at values of 1.0, 1.5 and 2.0 for this parameter. Qualitative results illustrate the development of the mixing zone from the exit plane of the model to a distance of about 19 equivalent rocket nozzle exit diameters downstream. These data show the mixing to be confined in the vertical plane for all cases, The lateral expansion is more pronounced at a pressure ratio of 1.0 and suggests that mixing with the ingested flow would be likely beginning at a distance of 7 nozzle exit diameters downstream of the nozzle exit plane.

  9. National Rivers and Streams Assessment

    EPA Pesticide Factsheets

    The NRSA is a collaborative, statistical survey of the nation's rivers and streams. It is one of four national surveys that EPA and its partners conduct to assess the condition and health of the nation's water resources.

  10. ATLAS Live: Collaborative Information Streams

    NASA Astrophysics Data System (ADS)

    Goldfarb, Steven; ATLAS Collaboration

    2011-12-01

    I report on a pilot project launched in 2010 focusing on facilitating communication and information exchange within the ATLAS Collaboration, through the combination of digital signage software and webcasting. The project, called ATLAS Live, implements video streams of information, ranging from detailed detector and data status to educational and outreach material. The content, including text, images, video and audio, is collected, visualised and scheduled using digital signage software. The system is robust and flexible, utilizing scripts to input data from remote sources, such as the CERN Document Server, Indico, or any available URL, and to integrate these sources into professional-quality streams, including text scrolling, transition effects, inter and intra-screen divisibility. Information is published via the encoding and webcasting of standard video streams, viewable on all common platforms, using a web browser or other common video tool. Authorisation is enforced at the level of the streaming and at the web portals, using the CERN SSO system.

  11. Video streaming into the mainstream.

    PubMed

    Garrison, W

    2001-12-01

    Changes in Internet technology are making possible the delivery of a richer mixture of media through data streaming. High-quality, dynamic content, such as video and audio, can be incorporated into Websites simply, flexibly and interactively. Technologies such as G3 mobile communication, ADSL, cable and satellites enable new ways of delivering medical services, information and learning. Systems such as Quicktime, Windows Media and Real Video provide reliable data streams as video-on-demand and users can tailor the experience to their own interests. The Learning Development Centre at the University of Portsmouth have used streaming technologies together with e-learning tools such as dynamic HTML, Flash, 3D objects and online assessment successfully to deliver on-line course content in economics and earth science. The Lifesign project--to develop, catalogue and stream health sciences media for teaching--is described and future medical applications are discussed.

  12. Streaming in English Primary Schools

    ERIC Educational Resources Information Center

    Acland, H.

    1973-01-01

    This paper seeks to extend our knowledge of ability grouping through the reanalysis of two sets of survey data, the Plowden survey (Peaker, 1967) and the NFER streaming survey (Barker Lunn, 1970). (Editor)

  13. MVSP: multithreaded VLIW stream processor

    NASA Astrophysics Data System (ADS)

    Sardashti, Somayeh; Ghasemi, Hamid Reza; Fatemi, Omid

    2006-02-01

    Stream processing is a new trend in computer architecture design which fills the gap between inflexible special-purpose media architectures and programmable architectures with low computational ability for media processing. Stream processors are designed for computationally intensive media applications characterized by high data parallelism and producer-consumer locality with little global data reuse. In this paper, we propose a new stream processor, named MVSP1. This processor is a programmable stream processor based on Imagine [1]. MVSP exploits TLP2, DLP 3, SP 4 and ILP 5 parallelisms inherent in media applications. Full simulator of MVSP has been implemented and several media workloads composed of EEMBC [2] benchmarks have been applied. The simulation results show the performance and functional unit utilization improvements of more than two times in comparison with Imagine processor.

  14. Cellular Subcompartments through Cytoplasmic Streaming.

    PubMed

    Pieuchot, Laurent; Lai, Julian; Loh, Rachel Ann; Leong, Fong Yew; Chiam, Keng-Hwee; Stajich, Jason; Jedd, Gregory

    2015-08-24

    Cytoplasmic streaming occurs in diverse cell types, where it generally serves a transport function. Here, we examine streaming in multicellular fungal hyphae and identify an additional function wherein regimented streaming forms distinct cytoplasmic subcompartments. In the hypha, cytoplasm flows directionally from cell to cell through septal pores. Using live-cell imaging and computer simulations, we identify a flow pattern that produces vortices (eddies) on the upstream side of the septum. Nuclei can be immobilized in these microfluidic eddies, where they form multinucleate aggregates and accumulate foci of the HDA-2 histone deacetylase-associated factor, SPA-19. Pores experiencing flow degenerate in the absence of SPA-19, suggesting that eddy-trapped nuclei function to reinforce the septum. Together, our data show that eddies comprise a subcellular niche favoring nuclear differentiation and that subcompartments can be self-organized as a consequence of regimented cytoplasmic streaming.

  15. MODELING PLUMES IN SMALL STREAMS

    EPA Science Inventory

    Pesticides accumulate on land surfaces from agricultural, commercial, and domestic application, and wash into streams and rivers during dry and wet weather. Flood water retention basins or structures often collect this contaminated runoff, providing intermediate storage and limit...

  16. Stream Mitigation Protocol Compendium - 2004

    EPA Pesticide Factsheets

    This document is intended as a reference in order to select, adapt, or devise stream assessment methods appropriate for impact assessment and mitigation of fluvial resources in the CWA Section 404 Program.

  17. Geomorphology of ice stream beds: recent progress and future challenges

    NASA Astrophysics Data System (ADS)

    Stokes, Chris R.

    2016-04-01

    Ice sheets lose mass primarily by melting and discharge via rapidly-flowing ice streams. Surface and basal melting (e.g. of ice shelves) are closely linked to atmospheric and oceanic conditions, but the mechanisms that drive changes in ice stream discharge are more complex; and are influenced by conditions at their bed which can sustain, enhance or inhibit their motion. Although explicit comparisons are rare, the ice-bed interface is similar to the 'boundary layer' in fluvial and aeolian environments, where shear stresses (both basal and lateral in the case of ice streams) oppose the flow of the overlying medium. The analogy extends further because processes within the boundary layer create a distinctive geomorphology (and roughness) that is characterised by subglacial bedforms that resemble features in fluvial and aeolian environments. Their creation results from erosion, transport and deposition of sediment which is poorly constrained, but which is intimately linked to the mechanisms through which ice streams are able to flow rapidly. The study of ice stream geomorphology is, therefore, critical to our understanding of their dynamics. Despite difficulty in observing the subglacial environment of active ice streams, our understanding of their geomorphology has grown rapidly in the last three decades, from almost complete ignorance to a detailed knowledge of their geomorphological products. This has been brought about by two main approaches: (i) geophysical investigation of modern (active) ice streams, and (ii) sedimentological and geomorphological investigation of palaeo-ice stream beds. The aim of this paper is to review progress in these two areas, highlight the key questions that remain, and discuss the opportunities that are likely to arise that will enable them to be addressed. It is clear that whilst these two main approaches have led to important advances, they have often been viewed as separate sub-disciplines, with minimal cross-pollination of ideas and

  18. Morphological assessment of reconstructed lowland streams in the Netherlands

    NASA Astrophysics Data System (ADS)

    Eekhout, Joris P. C.; Hoitink, Antonius J. F.; de Brouwer, Jan H. F.; Verdonschot, Piet F. M.

    2015-07-01

    Channelisation measures taken halfway the 20th century have had destructive consequences for the diversity of the ecology in the majority of the lowland streams in countries such as the Netherlands. Re-meandering is the common practice in restoring these lowland streams. Three reconstructed streams were monitored during the initial two years after construction of a new channel. The monitoring program included morphological surveys, sediment sampling, habitat pattern surveys, and discharge and water level measurements. Adjustments of the longitudinal bed profile formed the main morphological response. These adjustments were most likely caused by a lack of longitudinal connectivity of the streams as a whole, interrupting transport of sediment at locations of weirs and culverts. Bank erosion was observed only in a limited number of channel bends, and was often related to floodplain heterogeneity. Longitudinal channel bed adjustments and bank erosion were mainly caused by exogenous influences. In channel bends, the cross-sectional shape transformed from trapezoidal to the typical asymmetrical shape as found in meandering rivers. This behaviour can be attributed to an autogenous response to the prevailing flow conditions. Due to the prevailing fine sediment characteristics, bed material is readily set in motion and is being transported during the entire year. The existing design principles fail to address the initial morphological development after reconstruction. An evaluation of pre-set targets to realise water depth and flow velocity ranges shows the current procedures to be deficient. Based on this unfavourable evaluation, and the two-dimensional nature of habitat patterns needed to improve the conditions for stream organisms, we recommend to predict morphological developments as part of the design procedures for lowland stream restoration in the Netherlands.

  19. Morphological Assessment of Reconstructed Lowland Streams in the Netherlands

    NASA Astrophysics Data System (ADS)

    Hoitink, T.; Eekhout, J.; de Brouwer, J.; Verdonschot, P.

    2014-12-01

    Channelisation measures taken halfway the 20th century have had destructive consequences for the diversity of the ecology in the majority of the lowland streams in countries such as the Netherlands. Re-meandering is the common practice in restoring these lowland streams. Three lowland streams were monitored during the initial two years after construction of a new channel. The monitoring program included morphological surveys, sediment sampling, habitat pattern surveys, and discharge and water level measurements. Adjustments of the longitudinal bed profile formed the main morphological response. These adjustments were most likely caused by a lack of longitudinal connectivity of the streams as a whole, interrupting transport of sediment at locations of weirs and culverts. Bank erosion was observed only in a limited number of channel bends, and was often related to floodplain heterogeneity. Longitudinal channel bed adjustments and bank erosion were mainly caused by exogenous influences. In channel bends, the cross-sectional shape transformed from trapezoidal to the typical asymmetrical shape as found in meandering rivers. This behaviour can be attributed to an autogenous response to the prevailing flow conditions. Due to the prevailing fine sediment characteristics, bed material is readily set in motion and is being transported during the entire year. The existing design principles fail to address the initial morphological development after reconstruction. An evaluation of pre-set targets to realize water depth and flow velocity ranges shows the current procedures to be deficient. Based on this unfavourable evaluation, and the two-dimensional nature of habitat patterns needed to improve the conditions for stream organisms, we recommend to predict morphological developments as part of the design procedures for lowland stream restoration in the Netherlands.

  20. Dragging force on galaxies due to streaming dark matter

    NASA Technical Reports Server (NTRS)

    Hara, Tetsuya; Miyoshi, Shigeru

    1990-01-01

    It has been reported that galaxies in large regions (approx. 10(exp 2) Mpc), including some clusters of galaxies, may be streaming coherently with velocities up to 600 km/sec or more with respect to the rest frame determined by the microwave background radiation. On the other hand, it is suggested that the dominant mass component of the universe is dark matter. Because we can only speculate the motion of dark matter from the galaxy motions, much attention should be paid to the correlation of velocities between the observed galaxies and cold dark matter. So the authors investigated whether such coherent large-scale streaming velocities are due to dark matter or only to baryonic objects which may be formed by piling up of gases due to some explosive events. It seems that, although each galaxy will not follow the motion of dark matter, clusters of galaxies may represent the velocity field of dark matter. The origin of the velocity field of dark matter would be due to the initial adiabatic perturbations and, in fact, the observed peculiar velocities of clusters are within the allowed region constrained from the isotropy of the microwave background radiation.

  1. PROMOTIONS: PROper MOTION Software

    NASA Astrophysics Data System (ADS)

    Caleb Wherry, John; Sahai, R.

    2009-05-01

    We report on the development of a software tool (PROMOTIONS) to streamline the process of measuring proper motions of material in expanding nebulae. Our tool makes use of IDL's widget programming capabilities to design a unique GUI that is used to compare images of the objects from two epochs. The software allows us to first orient and register the images to a common frame of reference and pixel scale, using field stars in each of the images. We then cross-correlate specific morphological features in order to determine their proper motions, which consist of the proper motion of the nebula as a whole (PM-neb), and expansion motions of the features relative to the center. If the central star is not visible (quite common in bipolar nebulae with dense dusty waists), point-symmetric expansion is assumed and we use the average motion of high-quality symmetric pairs of features on opposite sides of the nebular center to compute PM-neb. This is then subtracted out to determine the individual movements of these and additional features relative to the nebular center. PROMOTIONS should find wide applicability in measuring proper motions in astrophysical objects such as the expanding outflows/jets commonly seen around young and dying stars. We present first results from using PROMOTIONS to successfully measure proper motions in several pre-planetary nebulae (transition objects between the red giant and planetary nebula phases), using images taken 7-10 years apart with the WFPC2 and ACS instruments on board HST. The authors are grateful to NASA's Undergradute Scholars Research Program (USRP) for supporting this research.

  2. Global motion perception is independent from contrast sensitivity for coherent motion direction discrimination and visual acuity in 4.5-year-old children

    PubMed Central

    Chakraborty, Arijit; Anstice, Nicola S.; Jacobs, Robert J.; Paudel, Nabin; LaGasse, Linda L.; Lester, Barry M.; Wouldes, Trecia A.; Harding, Jane E.; Thompson, Benjamin

    2015-01-01

    Global motion processing depends on a network of brain regions that includes extrastriate area V5 in the dorsal visual stream. For this reason, psychophysical measures of global motion perception have been used to provide a behavioural measure of dorsal stream function. This approach assumes that global motion is relatively independent of visual functions that arise earlier in the visual processing hierarchy such as contrast sensitivity and visual acuity. We tested this assumption by assessing the relationships between global motion perception, contrast sensitivity for coherent motion direction discrimination (henceforth referred to as contrast sensitivity) and habitual visual acuity in a large group of 4.5-year-old children (n = 117). The children were born at risk of abnormal neurodevelopment because of prenatal drug exposure or risk factors for neonatal hypoglycaemia. Motion coherence thresholds, a measure of global motion perception, were assessed using random dot kinematograms. The contrast of the stimuli was fixed at 100% and coherence was varied. Contrast sensitivity was measured using the same stimuli by fixing motion coherence at 100% and varying dot contrast. Stereoacuity was also measured. Motion coherence thresholds were not correlated with contrast sensitivity or visual acuity. However, lower (better) motion coherence thresholds were correlated with finer stereoacuity (rho=0.38, p=0.004). Contrast sensitivity and visual acuity were also correlated (rho= −0.26, p=0.004) with each other. These results indicate that global motion perception for high contrast stimuli is independent of contrast sensitivity and visual acuity and can be used to assess motion integration mechanisms in children. PMID:26318529

  3. The Northeast Stream Quality Assessment

    USGS Publications Warehouse

    Van Metre, Peter C.; Riva-Murray, Karen; Coles, James F.

    2016-04-22

    In 2016, the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) is assessing stream quality in the northeastern United States. The goal of the Northeast Stream Quality Assessment (NESQA) is to assess the quality of streams in the region by characterizing multiple water-quality factors that are stressors to aquatic life and evaluating the relation between these stressors and biological communities. The focus of NESQA in 2016 will be on the effects of urbanization and agriculture on stream quality in all or parts of eight states: Connecticut, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont.Findings will provide the public and policymakers with information about the most critical factors affecting stream quality, thus providing insights about possible approaches to protect the health of streams in the region. The NESQA study will be the fourth regional study conducted as part of NAWQA and will be of similar design and scope to the first three, in the Midwest in 2013, the Southeast in 2014, and the Pacific Northwest in 2015 (http://txpub.usgs.gov/RSQA/).

  4. Lexical Influences on Auditory Streaming

    PubMed Central

    Billig, Alexander J.; Davis, Matthew H.; Deeks, John M.; Monstrey, Jolijn; Carlyon, Robert P.

    2013-01-01

    Summary Biologically salient sounds, including speech, are rarely heard in isolation. Our brains must therefore organize the input arising from multiple sources into separate “streams” and, in the case of speech, map the acoustic components of the target signal onto meaning. These auditory and linguistic processes have traditionally been considered to occur sequentially and are typically studied independently [1, 2]. However, evidence that streaming is modified or reset by attention [3], and that lexical knowledge can affect reports of speech sound identity [4, 5], suggests that higher-level factors may influence perceptual organization. In two experiments, listeners heard sequences of repeated words or acoustically matched nonwords. After several presentations, they reported that the initial /s/ sound in each syllable formed a separate stream; the percept then fluctuated between the streamed and fused states in a bistable manner. In addition to measuring these verbal transformations, we assessed streaming objectively by requiring listeners to detect occasional targets—syllables containing a gap after the initial /s/. Performance was better when streaming caused the syllables preceding the target to transform from words into nonwords, rather than from nonwords into words. Our results show that auditory stream formation is influenced not only by the acoustic properties of speech sounds, but also by higher-level processes involved in recognizing familiar words. PMID:23891107

  5. It's, Like, Relative Motion at the Mall

    NASA Astrophysics Data System (ADS)

    Robinett, R. W.

    2003-03-01

    Almost all introductory textbooks, both algebra- and calculus-based, include sections on relative motion and relative velocity, in both one and two dimensions. The most popular examples in discussions of 2-D relative velocity in such texts seem to be the motion of airplanes/blimps flying in the presence of wind or the conceptually identical cases of boats/rafts piloted across rivers/streams, including the effects of currents. These and similar cases are rather removed from the everyday experience of some students, and the use of simple lecture demonstrations to illustrate these concepts can be quite useful. For example, the motion of a simple toy "wind-up" car moving at constant speed across a horizontal tabletop, with a plastic sheet underneath providing the "moving frame of reference," can illustrate many aspects of such problems, including the need to "point" the plane/boat in an appropriate direction, just as illustrated in many textbook figures. On the other hand, it is also useful if students can directly experience concepts for themselves, especially in a kinesthetic manner, but there are seemingly far fewer human-sized lecture demonstrations on this topic. In this paper, we will point out one such example which might well be just a short drive away.

  6. Stray, swing and scatter: angular momentum evolution of orbits and streams in aspherical potentials

    NASA Astrophysics Data System (ADS)

    Erkal, Denis; Sanders, Jason L.; Belokurov, Vasily

    2016-09-01

    In aspherical potentials orbital planes continuously evolve. The gravitational torques impel the angular momentum vector to precess, that is to slowly stray around the symmetry axis, and nutate, i.e. swing up and down periodically in the perpendicular direction. This familiar orbital pole motion - if detected and measured - can reveal the shape of the underlying gravitational potential, the quantity only crudely gauged in the Galaxy so far. Here we demonstrate that the debris poles of stellar tidal streams show a very similar straying and swinging behaviour, and give analytic expressions to link the amplitude and the frequency of the pole evolution to the flattening of the dark matter distribution. While these results are derived for near-circular orbits, we show they are also valid for eccentric orbits. Most importantly, we explain how the differential orbital plane precession leads to the broadening of the stream and show that streams on polar orbits ought to scatter faster. We provide expressions for the stream width evolution as a function of the axisymmetric potential flattening and the angle from the symmetry plane and prove that our models are in good agreement with streams produced in N-body simulations. Interestingly, the same intuition applies to streams whose progenitors are on short- or long-axis loops in a triaxial potential. Finally, we present a compilation of the Galactic cold stream data, and discuss how the simple picture developed here, along with stream modelling, can be used to constrain the symmetry axes and flattening of the Milky Way.

  7. Numerical simulation of 3D boundary-driven acoustic streaming in microfluidic devices.

    PubMed

    Lei, Junjun; Hill, Martyn; Glynne-Jones, Peter

    2014-02-07

    This article discusses three-dimensional (3D) boundary-driven streaming in acoustofluidic devices. Firstly, the 3D Rayleigh streaming pattern in a microchannel is simulated and its effect on the movement of microparticles of various sizes is demonstrated. The results obtained from this model show good comparisons with 3D experimental visualisations and demonstrate the fully 3D nature of the acoustic streaming field and the associated acoustophoretic motion of microparticles in acoustofluidic devices. This method is then applied to another acoustofluidic device in order to gain insights into an unusual in-plane streaming pattern. The origin of this streaming has not been fully described and its characteristics cannot be explained from the classical theory of Rayleigh streaming. The simulated in-plane streaming pattern was in good agreement with the experimental visualisation. The mechanism behind it is shown to be related to the active sound intensity field, which supports our previous findings on the mechanism of the in-plane acoustic streaming pattern visualised and modelled in a thin-layered capillary device.

  8. TIDAL STREAM MORPHOLOGY AS AN INDICATOR OF DARK MATTER HALO GEOMETRY: THE CASE OF PALOMAR 5

    SciTech Connect

    Pearson, Sarah; Johnston, Kathryn V.; Price-Whelan, Adrian M.; Küpper, Andreas H. W.

    2015-01-20

    This paper presents an example where the morphology of a single stellar stream can be used to rule out a specific galactic potential form without the need for velocity information. We investigate the globular cluster Palomar 5 (Pal 5), which is tidally disrupting into a cold, thin stream mapped over 22 deg on the sky with a typical width of 0.7 deg. We generate models of this stream by fixing Pal 5's present-day position, distance, and radial velocity via observations, while allowing its proper motion to vary. In a spherical dark matter halo we easily find models that fit the observed morphology. However, no plausible Pal 5 model could be found in the triaxial potential of Law and Majewski, which has been proposed to explain the properties of the Sagittarius stream. In this case, the long, thin, and curved morphology of the Pal 5 stream alone can be used to rule out such a potential configuration. Pal 5-like streams in this potential are either too straight, missing the curvature of the observations, or show an unusual morphology which we dub stream-fanning: a signature sensitive to the triaxiality of a potential. We conclude that the mere existence of other thin tidal streams must provide broad constraints on the orientation and shape of the dark matter halo they inhabit.

  9. Characterization of HIFU transducers designed for sonochemistry application: Acoustic streaming.

    PubMed

    Hallez, L; Touyeras, F; Hihn, J-Y; Bailly, Y

    2016-03-01

    Cavitation distribution in a High Intensity Focused Ultrasound sonoreactors (HIFU) has been extensively described in the recent literature, including quantification by an optical method (Sonochemiluminescence SCL). The present paper provides complementary measurements through the study of acoustic streaming generated by the same kind of HIFU transducers. To this end, results of mass transfer measurements (electrodiffusional method) were compared to optical method ones (Particle Image Velocimetry). This last one was used in various configurations: with or without an electrode in the acoustic field in order to have the same perturbation of the wave propagation. Results show that the maximum velocity is not located at the focal but shifted near the transducer, and that this shift is greater for high powers. The two cavitation modes (stationary and moving bubbles) are greatly affect the hydrodynamic behavior of our sonoreactors: acoustic streaming and the fluid generated by bubble motion. The results obtained by electrochemical measurements show the same low hydrodynamic activity in the transducer vicinity, the same shift of the active focal toward the transducer, and the same absence of activity in the post-focal axial zone. The comparison with theoretical Eckart's velocities (acoustic streaming in non-cavitating media) confirms a very high activity at the "sonochemical focal", accounted for by wave distortion, which induced greater absorption coefficients. Moreover, the equivalent liquid velocities are one order of magnitude larger than the ones measured by PIV, confirming the enhancement of mass transfer by bubbles oscillation and collapse close to the surface, rather than from a pure streaming effect.

  10. Yugoslav strong motion network

    NASA Astrophysics Data System (ADS)

    Mihailov, Vladimir

    1985-04-01

    Data concerning ground motion and the response of structures during strong earthquakes are necessary for seismic hazard evaluation and the definition of design criteria for structures to be constructed in seismically active zones. The only way to obtain such data is the installation of a strong-motion instrument network. The Yugoslav strong-motion programme was created in 1972 to recover strong-motion response data used by the structural engineering community in developing earthquake resistant design. Instruments, accelerographs SMA-1 and seismoscopes WM-1, were installed in free-field stations and on structures (high-rise buildings, dams, bridges, etc.). A total number of 176 accelerographs and 137 seismoscopes have been installed and are operating in Yugoslavia. The strong-motion programme in Yugoslavia consists of five subactivities: network design, network operation, data processing, network management and research as well as application. All these activities are under the responsibility of IZIIS in cooperation with the Yugoslav Association of Seismology. By 1975 in the realisation of this project participated the CALTECH as cooperative institution in the joint American-Yugoslav cooperative project. The results obtained which are presented in this paper, and their application in the aseismic design justify the necessity for the existence of such a network in Yugoslavia.

  11. Space motion sickness

    NASA Technical Reports Server (NTRS)

    Homick, J. L.

    1979-01-01

    Research on the etiology, prediction, treatment and prevention of space motion sickness, designed to minimize the impact of this syndrome which was experienced frequently and with severity by individuals on the Skylab missions, on Space Shuttle crews is reviewed. Theories of the cause of space motion sickness currently under investigation by NASA include sensory conflict, which argues that motion sickness symptoms result from a mismatch between the total pattern of information from the spatial senses and that stored from previous experiences, and fluid shift, based upon the redistribution of bodily fluids that occurs upon continued exposure to weightlessness. Attempts are underway to correlate space motion sickness susceptibility to different provocative environments, vestibular and nonvestibular responses, and the rate of acquisition and length of retention of sensory adaptation. Space motion sickness countermeasures under investigation include various drug combinations, of which the equal combination of promethazine and ephedrine has been found to be as effective as the scopolomine and dexedrine combination, and vestibular adaptation and biofeedback training and autogenic therapy.

  12. The Particle--Motion Problem.

    ERIC Educational Resources Information Center

    Demana, Franklin; Waits, Bert K.

    1993-01-01

    Discusses solutions to real-world linear particle-motion problems using graphing calculators to simulate the motion and traditional analytic methods of calculus. Applications include (1) changing circular or curvilinear motion into linear motion and (2) linear particle accelerators in physics. (MDH)

  13. Miscellaneous streams best management practices (BMP) report

    SciTech Connect

    Lueck, K.J., Westinghouse Hanford

    1996-07-24

    The Washington State Department of Ecology (Ecology) and U.S. Department of Energy Consent Order No. DE 91NM-177 (Consent Order) lists regulatory milestones for liquid effluent streams at the Hanford Site to comply with the permitting requirements of Washington Administrative Code (WAC) 173-216 (`State Waste Discharge Permit Program`) or WAC 173-218 (`Washington Underground Injection Control Program`) where applicable. Hanford Site liquid effluent streams discharging to the soil column are categorized as Phase I and Phase II Streams, and Miscellaneous Streams. There were originally 33 Phase I and Phase II Streams, however some of these streams have been eliminated. Miscellaneous Streams are those liquid effluent streams discharged to the ground that are not categorized as Phase I or Phase II Streams, and are subject to the requirements of several milestones identified in the Consent Order. The three criteria for identifying streams that are potentially affecting groundwater are: (1) streams discharging to surface contaminated areas (referred to as category `b` streams); (2) potentially contaminated streams (referred to as category `c` streams); and (3) streams discharging within 91 meters (300 feet) of a contaminated crib, ditch, or trench (referred to as category `d` streams). Miscellaneous Streams that meet any of these criteria must be evaluated for application of best management practices (BMP). The purpose of this report is to provide the best management practice preferred alternative. The list of BMP streams has been revised since the original submittal. Several streams from the original list of BMP streams have already been eliminated through facility upgrades, reduction of steam usage, and facility shutdowns. This document contains a description of the changes to the list of BMP streams, applicable definitions and regulatory requirements and possible alternatives, and a schedule for implementing the preferred alternatives.

  14. Unique Challenges to (Federal) Enterprise Streaming

    NASA Technical Reports Server (NTRS)

    Walls, Bryan

    2006-01-01

    Enterprise streaming has different parameters than consumer Streaming. The government enterprise has some differences on top of that. I'd like to highlight some issues shared by the Federal government as a whole, with a closer look at streaming within NASA. Then we'll look at NASA's strategy for streaming.

  15. THE DYNAMICS OF STAR STREAM GAPS

    SciTech Connect

    Carlberg, R. G.

    2013-10-01

    A massive object crossing a narrow stream of stars orbiting in the halo of the galaxy induces velocity changes both along and transverse to the stream that can lead to the development of a visible gap. For a stream narrow relative to its orbital radius, the stream crossing time is sufficiently short that the impact approximation can be used to derive the changes in angular momenta and radial actions along the star stream. The epicyclic approximation is used to calculate the evolution of the density of the stream as it orbits around in a galactic potential. Analytic expressions are available for a point mass, however, the general expressions are easily numerically evaluated for perturbing objects with arbitrary density profiles. With a simple allowance for the velocity dispersion of the stream, moderately warm streams can be modeled. The predicted evolution agrees well with the outcomes of simulations of stellar streams for streams with widths up to 1% of the orbital radius of the stream. The angular momentum distribution within the stream shears out gaps with time, further reducing the visibility of streams, although the size of the shear effect requires more detailed simulations that account for the creation of the stream. An illustrative model indicates that shear will set a lower limit of a few times the stream width for the length of gaps that persist. In general, the equations are useful for dynamical insights into the development of stream gaps and their measurement.

  16. Brownian motion of graphene.

    PubMed

    Maragó, Onofrio M; Bonaccorso, Francesco; Saija, Rosalba; Privitera, Giulia; Gucciardi, Pietro G; Iatì, Maria Antonia; Calogero, Giuseppe; Jones, Philip H; Borghese, Ferdinando; Denti, Paolo; Nicolosi, Valeria; Ferrari, Andrea C

    2010-12-28

    Brownian motion is a manifestation of the fluctuation-dissipation theorem of statistical mechanics. It regulates systems in physics, biology, chemistry, and finance. We use graphene as prototype material to unravel the consequences of the fluctuation-dissipation theorem in two dimensions, by studying the Brownian motion of optically trapped graphene flakes. These orient orthogonal to the light polarization, due to the optical constants anisotropy. We explain the flake dynamics in the optical trap and measure force and torque constants from the correlation functions of the tracking signals, as well as comparing experiments with a full electromagnetic theory of optical trapping. The understanding of optical trapping of two-dimensional nanostructures gained through our Brownian motion analysis paves the way to light-controlled manipulation and all-optical sorting of biological membranes and anisotropic macromolecules.

  17. Intrinsic Feature Motion Tracking

    SciTech Connect

    Goddard, Jr., James S.

    2013-03-19

    Subject motion during 3D medical scanning can cause blurring and artifacts in the 3D images resulting in either rescans or poor diagnosis. Anesthesia or physical restraints may be used to eliminate motion but are undesirable and can affect results. This software measures the six degree of freedom 3D motion of the subject during the scan under a rigidity assumption using only the intrinsic features present on the subject area being monitored. This movement over time can then be used to correct the scan data removing the blur and artifacts. The software acquires images from external cameras or images stored on disk for processing. The images are from two or three calibrated cameras in a stereo arrangement. Algorithms extract and track the features over time and calculate position and orientation changes relative to an initial position. Output is the 3D position and orientation change measured at each image.

  18. Motion detector and analyzer

    DOEpatents

    Unruh, W.P.

    1987-03-23

    Method and apparatus are provided for deriving positive and negative Doppler spectrum to enable analysis of objects in motion, and particularly, objects having rotary motion. First and second returned radar signals are mixed with internal signals to obtain an in-phase process signal and a quadrature process signal. A broad-band phase shifter shifts the quadrature signal through 90/degree/ relative to the in-phase signal over a predetermined frequency range. A pair of signals is output from the broad-band phase shifter which are then combined to provide a first side band signal which is functionally related to a negative Doppler shift spectrum. The distinct positive and negative Doppler spectra may then be analyzed for the motion characteristics of the object being examined.

  19. Muscle Motion Solenoid Actuator

    NASA Astrophysics Data System (ADS)

    Obata, Shuji

    It is one of our dreams to mechanically recover the lost body for damaged humans. Realistic humanoid robots composed of such machines require muscle motion actuators controlled by all pulling actions. Particularly, antagonistic pairs of bi-articular muscles are very important in animal's motions. A system of actuators is proposed using the electromagnetic force of the solenoids with the abilities of the stroke length over 10 cm and the strength about 20 N, which are needed to move the real human arm. The devised actuators are based on developments of recent modern electro-magnetic materials, where old time materials can not give such possibility. Composite actuators are controlled by a high ability computer and software making genuine motions.

  20. The Midwest Stream Quality Assessment

    USGS Publications Warehouse

    ,

    2012-01-01

    In 2013, the U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) and USGS Columbia Environmental Research Center (CERC) will be collaborating with the U.S. Environmental Protection Agency (EPA) National Rivers and Streams Assessment (NRSA) to assess stream quality across the Midwestern United States. The sites selected for this study are a subset of the larger NRSA, implemented by the EPA, States and Tribes to sample flowing waters across the United States (http://water.epa.gov/type/rsl/monitoring/riverssurvey/index.cfm). The goals are to characterize water-quality stressors—contaminants, nutrients, and sediment—and ecological conditions in streams throughout the Midwest and to determine the relative effects of these stressors on aquatic organisms in the streams. Findings will contribute useful information for communities and policymakers by identifying which human and environmental factors are the most critical in controlling stream quality. This collaborative study enhances information provided to the public and policymakers and minimizes costs by leveraging and sharing data gathered under existing programs. In the spring and early summer, NAWQA will sample streams weekly for contaminants, nutrients, and sediment. During the same time period, CERC will test sediment and water samples for toxicity, deploy time-integrating samplers, and measure reproductive effects and biomarkers of contaminant exposure in fish or amphibians. NRSA will sample sites once during the summer to assess ecological and habitat conditions in the streams by collecting data on algal, macroinvertebrate, and fish communities and collecting detailed physical-habitat measurements. Study-team members from all three programs will work in collaboration with USGS Water Science Centers and State agencies on study design, execution of sampling and analysis, and reporting.

  1. Fuel-cell engine stream conditioning system

    DOEpatents

    DuBose, Ronald Arthur

    2002-01-01

    A stream conditioning system for a fuel cell gas management system or fuel cell engine. The stream conditioning system manages species potential in at least one fuel cell reactant stream. A species transfer device is located in the path of at least one reactant stream of a fuel cell's inlet or outlet, which transfer device conditions that stream to improve the efficiency of the fuel cell. The species transfer device incorporates an exchange media and a sorbent. The fuel cell gas management system can include a cathode loop with the stream conditioning system transferring latent and sensible heat from an exhaust stream to the cathode inlet stream of the fuel cell; an anode humidity retention system for maintaining the total enthalpy of the anode stream exiting the fuel cell related to the total enthalpy of the anode inlet stream; and a cooling water management system having segregated deionized water and cooling water loops interconnected by means of a brazed plate heat exchanger.

  2. Possible Stick-Slip Mechanism for Whillans Ice Stream

    NASA Technical Reports Server (NTRS)

    Bindschadler, Robert; King, Matt; Vornberger, Patricia

    2003-01-01

    Tidally-induced stick-slip motion in the mouth of Whillans Ice Stream provides a unique natural experiment in ice-stream response behavior and fiom which we might learn a great deal about subglacial till properties and sub-ice-stream conditions. At the IGS Symposium on Fast Glacier Flow (Yakutat, 2002), we reported our observations of stick- slip motion and demonstrated its synchronicity with tidal forcing. Recently, we have completed additional processing of our GPS data in differential mode. It reveals more details of the stick-slip events and illustrates that within 30 seconds, the temporal interval of our data, the ice stream accelerates to a speed corresponding to a completely lubricated bed. While details of individual events vary, there seems to be strong evidence of an elastic rebound on the time scale of one hour following most events. This suggests the event involves the release of stored elastic strain energy in the ice. The similar displacements of events suggest further that till or subglacial hydrologic properties limit the amount of elastic strain released in any single event. We follow a line of reasoning that dilatant strengthening limits the slip displacement and present model of the stick-slip process. To match the observed delay between the peak ocean tide and stick-slip events, our model includes a propagating pressure wave in the subglacial hydrologic system between the grounding line, where the rising tide first increases the subglacial water pressure and regions upstream where stored elastic strain increases the basal shear stress. This high-tide event is released when the increased water pressure reaches the region of increased shear stress. Dilatant strengthening stops the event by increasing pore volume and lowering the water pressure. Following this event, falling tide increases the normal forces, compresses the till and increases pore pressure again, leading to the second falling-tide event we observe every tidal cycle.

  3. Possible Stick-Slip Mechanism for Whillans Ice Stream

    NASA Technical Reports Server (NTRS)

    Bindschadler, Robert; King, Matt; Vornberger, Patricia

    2003-01-01

    Tidally-induced stick-slip motion in the mouth of Whillans Ice Stream provides a unique natural experiment in ice-stream response behavior and from which we might learn a great deal about subglacial till properties and sub-ice-stream conditions. At the IGS Symposium on Fast Glacier Flow (Yakutat, 2002), we reported our observations of stick- slip motion and demonstrated its synchronicity with tidal forcing. Recently, we have completed additional processing of our GPS data in differential mode. It reveals more details of the stick-slip events and illustrates that within 30 seconds, the temporal interval of our data, the ice stream accelerates to a speed corresponding to a completely lubricated bed. While details of individual events vary, there seems to be strong evidence of an elastic rebound on the time scale of one hour following most events. This suggests the event involves the release of stored elastic strain energy in the ice. The similar displacements of events suggest further that till or subglacial hydrologic properties limit the amount of elastic strain released in any single event. We follow a line of reasoning that dilatant strengthening limits the slip displacement and present model of the stick-slip process. To match the observed delay between the peak ocean tide and stick-slip events, our model includes a propagating pressure wave in the subglacial hydrologic system between the grounding line, where the rising tide first increases the subglacial water pressure and regions upstream where stored elastic strain increases the basal shear stress. This high-tide event is released when the increased water pressure reaches the region of increased shear stress. Dilatant strengthening stops the event by increasing pore volume and lowering the water pressure. Following this event, falling tide increases the normal forces, compresses the till and increases pore pressure again, leading to the second falling-tide event we observe every tidal cycle.

  4. A Solar Electron Burst Spanning a Stream Interface: ACE Observations

    NASA Astrophysics Data System (ADS)

    Steinberg, J. T.; Skoug, R. M.; McComas, D. J.

    2009-12-01

    Where coronal hole fast wind runs into slow wind ahead, a compression region forms. The boundary between the compressed slow and fast wind is referred to as the stream interface (SI). Ideally, if the coronal source regions of slow and fast wind are distinct and stationary, and the interplanetary magnetic field (IMF) foot point locations are fixed, the SI is a discontinuous plasma boundary for both solar wind ions and 100eV-1keV suprathermal electrons which stream out from the sun through the ions along the IMF. In the ideal case, IMF lines do not cross the SI. However, field line crossing of the SI may result from IMF foot point motion during the time required for solar wind ions to travel from the sun to 1 AU. On January 29, 2005 ACE encountered a stream interface within a CIR at the leading edge of a coronal hole fast stream. A solar electron burst was observed from 11-15 UT at 0.5-1.3 keV energies. The burst was observed across the SI, indicating magnetic connection to the electron burst source region on both sides of the SI. This could indicate that the electron burst source region spanned a coronal hole boundary. A more likely alternative is that field lines on opposite sides of the SI at 1 AU were no longer connected to different sides of a coronal hole boundary. Instead, footpoint motion occurred during solar wind ion transit to 1 AU, so that field lines on both sides of the SI were connected to a single coronal electron burst source region.

  5. Tornadogenesis Versus Newton's Third Law of Motion

    NASA Astrophysics Data System (ADS)

    Hardwig, R. B.

    2015-12-01

    For over 90 years scientists have tried to explain how tornadoes form and function. The present general consensus is that a tornado is just a function of the thunderstorm. Much research has been done to find the answer and numerous articles and papers have been written, all to no avail. This research explores the fact that a tornado cannot be just a function of a thunderstorm, as there is no opposite force within the thunderstorm to the air drawn up by the tornado, so there must be some external force involved in a tornado's formation. To have compliance with Newton's Third Law of Motion we must see an equal downforce or some other force within the thunderstorm, to that drawn up by the tornado. And if there was a downforce, that force would be virtually as damaging as the tornado itself. But we don't see this downforce or any other opposing force within the thunderstorm. Therefore, we must look for some other force that could cause a tornado's formation. And if that opposing force is not within the thunderstorm we need to be looking for some external force, outside the thunderstorm, that could cause a tornado. Also the fact that we have Waterspouts, Landspouts and Gustnadoes all without a thunderstorm, but since they all look and function just like a tornado, tells us that there must be some other force that is responsible for causing a tornado just like a Waterspout, Landspout or Gustnado. My research shows that there is one other force of energy that could cause all of these vortexes and is most likely the source of energy for a tornado's formation. That force is the High Velocity Overhead Jet Stream. My research shows a direct relationship between the High Velocity Overhead Jet Stream and Tornadogenesis as well as Waterspouts, Landspouts and Gustnadoes. Therefore, with the High Velocity Overhead Jet Stream providing the Action, at its interface with the tornado in the stratosphere, the Reaction is what we see on the ground as a tornado. With this explanation we

  6. Dislocation motion and instability

    NASA Astrophysics Data System (ADS)

    Zhu, Yichao; Chapman, Stephen Jonathan; Acharya, Amit

    2013-08-01

    The Peach-Koehler expression for the stress generated by a single (non-planar) curvilinear dislocation is evaluated to calculate the dislocation self stress. This is combined with a law of motion to give the self-induced motion of a general dislocation curve. A stability analysis of a rectilinear, uniformly translating dislocation is then performed. The dislocation is found to be susceptible to a helical instability, with the maximum growth rate occurring when the dislocation is almost, but not exactly, pure screw. The non-linear evolution of the instability is determined numerically, and implications for slip band formation and non-Schmid behavior in yielding are discussed.

  7. Motion in microfluidic ratchets.

    PubMed

    Caballero, D; Katuri, J; Samitier, J; Sánchez, S

    2016-11-15

    The ubiquitous random motion of mesoscopic active particles, such as cells, can be "rectified" or directed by embedding the particles in systems containing local and periodic asymmetric cues. Incorporated on lab-on-a-chip devices, these microratchet-like structures can be used to self-propel fluids, transport particles, and direct cell motion in the absence of external power sources. In this Focus article we discuss recent advances in the use of ratchet-like geometries in microfluidics which could open new avenues in biomedicine for applications in diagnosis, cancer biology, and bioengineering.

  8. Analysis of swimming motions.

    NASA Technical Reports Server (NTRS)

    Gallenstein, J.; Huston, R. L.

    1973-01-01

    This paper presents an analysis of swimming motion with specific attention given to the flutter kick, the breast-stroke kick, and the breast stroke. The analysis is completely theoretical. It employs a mathematical model of the human body consisting of frustrums of elliptical cones. Dynamical equations are written for this model including both viscous and inertia forces. These equations are then applied with approximated swimming strokes and solved numerically using a digital computer. The procedure is to specify the input of the swimming motion. The computer solution then provides the output displacement, velocity, and rotation or body roll of the swimmer.

  9. Induced motion at texture-defined motion boundaries.

    PubMed Central

    Johnston, A; Benton, C P; McOwan, P W

    1999-01-01

    When a static textured background is covered and uncovered by a moving bar of the same mean luminance we can clearly see the motion of the bar. Texture-defined motion provides an example of a naturally occurring second-order motion. Second-order motion sequences defeat standard spatio-temporal energy models of motion perception. It has been proposed that second-order stimuli are analysed by separate systems, operating in parallel with luminance-defined motion processing, which incorporate identifiable pre-processing stages that make second-order patterns visible to standard techniques. However, the proposal of multiple paths to motion analysis remains controversial. Here we describe the behaviour of a model that recovers both luminance-defined and an important class of texture-defined motion. The model also accounts for the induced motion that is seen in some texture-defined motion sequences. We measured the perceived direction and speed of both the contrast envelope and induced motion in the case of a contrast modulation of static noise textures. Significantly, the model predicts the perceived speed of the induced motion seen at second-order texture boundaries. The induced motion investigated here appears distinct from classical induced effects resulting from motion contrast or the movement of a reference frame. PMID:10643088

  10. Mechanical guidance through cell-cell and cell-surface contact during multicellular streaming

    NASA Astrophysics Data System (ADS)

    Wang, Chenlu; Driscoll, Meghan; Gupta, Satyandra K.; Parent, Carole; Losert, Wolfgang

    2014-03-01

    During collective cell migration, mechanical forces arise from the extracellular matrix (ECM) through cell-surface contact and from other cells through cell-cell contact. These forces regulate the motion of migrating cell groups. To determine how these mechanical interactions balance during cell migration, we measured the shape dynamics of Dictyostelium discoideum cells at the multicellular streaming stage. We found that cells can coordinate their motion by synchronizing protrusion waves that travel along their membranes when they form proper cell-cell adhesion and cell-surface adhesion. In addition, our experiments on live actin labeled cells show that intracellular actin polymerization actively responds to the change of cell-cell/surface adhesion and helps to stabilize multicellular migration streams. Our finding suggests that the coordination of motion between neighboring cells in collective migration requires a balance between cell-cell adhesion and cell-surface adhesion, and that the cell cytoskeleton plays an important role in this balance.

  11. Bedload transport associated with high stream power, Jordan River, Israel

    PubMed Central

    Inbar, Moshe; Schick, Asher P.

    1979-01-01

    During a flood of a magnitude that recurs once in 100 years, boulders up to 1700 mm in size were transported in the Jordan and Meshushim Rivers, northern Israel. Bedload discharge rates were estimated for periods of 3-72 hr of peak flow by a combination of hydrologic and geomorphic methods. Bedload transport rate is proportional to unit stream power in excess of that necessary for initial motion, raised to the power 3/2, as has been shown for data on other rivers. PMID:16592661

  12. Streaming Compression of Hexahedral Meshes

    SciTech Connect

    Isenburg, M; Courbet, C

    2010-02-03

    We describe a method for streaming compression of hexahedral meshes. Given an interleaved stream of vertices and hexahedral our coder incrementally compresses the mesh in the presented order. Our coder is extremely memory efficient when the input stream documents when vertices are referenced for the last time (i.e. when it contains topological finalization tags). Our coder then continuously releases and reuses data structures that no longer contribute to compressing the remainder of the stream. This means in practice that our coder has only a small fraction of the whole mesh in memory at any time. We can therefore compress very large meshes - even meshes that do not file in memory. Compared to traditional, non-streaming approaches that load the entire mesh and globally reorder it during compression, our algorithm trades a less compact compressed representation for significant gains in speed, memory, and I/O efficiency. For example, on the 456k hexahedra 'blade' mesh, our coder is twice as fast and uses 88 times less memory (only 3.1 MB) with the compressed file increasing about 3% in size. We also present the first scheme for predictive compression of properties associated with hexahedral cells.

  13. Quasilinear saturation of the aperiodic ordinary mode streaming instability

    SciTech Connect

    Stockem Novo, A. Schlickeiser, R.; Yoon, P. H.; Lazar, M.; Poedts, S.; Seough, J.

    2015-09-15

    In collisionless plasmas, only kinetic instabilities and fluctuations are effective in reducing the free energy and scatter plasma particles, preventing an increase of their anisotropy. Solar energetic outflows into the interplanetary plasma give rise to important thermal anisotropies and counterstreaming motions of plasma shells, and the resulting instabilities are expected to regulate the expansion of the solar wind. The present paper combines quasilinear theory and kinetic particle-in-cell simulations in order to study the weakly nonlinear saturation of the ordinary mode in hot counter-streaming plasmas with a temperature anisotropy as a follow-up of the paper by Seough et al. [Phys. Plasmas 22, 082122 (2015)]. This instability provides a plausible mechanism for the origin of dominating, two-dimensional spectrum of transverse magnetic fluctuations observed in the solar wind. Stimulated by the differential motion of electron counterstreams the O mode instability may convert their free large-scale energy by nonlinear collisionless dissipation on plasma particles.

  14. A world in motion

    SciTech Connect

    Boynton, J.A.

    1994-12-31

    A World in Motion is a physical science curriculum supplement for grades four, five, and six which responds to the need to promote and teach sound science and mathematics concepts. Using the A World in Motion kits, teachers work in partnership with practicing engineer or scientists volunteers to provide students with fun, exciting, and relevant hands-on science and math experiences. During the A World in Motion experience, students work together in {open_quotes}Engineering Design Teams{close_quotes} exploring physics concepts through a series of activities. Each student is assigned a role as either a facilities engineer, development engineer, test engineer, or project engineer and is given responsibilities paralleling those of engineers in industry. The program culminates in a {open_quotes}Design Review{close_quotes} where students can communicate their results, demonstrate their designs, and receive recognition for their efforts. They are given a chance to take on responsibility and build self-esteem. Since January 1991, over 12,000 volunteers engineers have been involved with the program, with a distribution of 20,000 A World in Motion kit throughout the U.S. and Canada.

  15. Superluminal motion (review)

    NASA Astrophysics Data System (ADS)

    Malykin, G. B.; Romanets, E. A.

    2012-06-01

    Prior to the development of Special Relativity, no restrictions were imposed on the velocity of the motion of particles and material bodies, as well as on energy transfer and signal propagation. At the end of the 19th century and the beginning of the 20th century, it was shown that a charge that moves at a velocity faster than the speed of light in an optical medium, in particular, in vacuum, gives rise to impact radiation, which later was termed the Vavilov-Cherenkov radiation. Shortly after the development of Special Relativity, some researchers considered the possibility of superluminal motion. In 1923, the Soviet physicist L.Ya. Strum suggested the existence of tachyons, which, however, have not been discovered yet. Superluminal motions can occur only for images, e.g., for so-called "light spots," which were considered in 1972 by V.L. Ginzburg and B.M. Bolotovskii. These spots can move with a superluminal phase velocity but are incapable of transferring energy and information. Nevertheless, these light spots may induce quite real generation of microwave radiation in closed waveguides and create the Vavilov-Cherenkov radiation in vacuum. In this work, we consider various paradoxes, illusions, and artifacts associated with superluminal motion.

  16. Linear motion valve

    NASA Technical Reports Server (NTRS)

    Chandler, J. A. (Inventor)

    1985-01-01

    The linear motion valve is described. The valve spool employs magnetically permeable rings, spaced apart axially, which engage a sealing assembly having magnetically permeable pole pieces in magnetic relationship with a magnet. The gap between the ring and the pole pieces is sealed with a ferrofluid. Depletion of the ferrofluid is minimized.

  17. Planets in Motion

    ERIC Educational Resources Information Center

    Riddle, Bob

    2005-01-01

    All the planets in the solar system revolve around the Sun in the same direction, clockwise when viewed from above the North Pole. This is referred to as direct motion. From the perspective on the Earth's surface, the planets travel east across the sky in relation to the background of stars. The Sun also moves eastward daily, but this is an…

  18. Travelers' Health: Motion Sickness

    MedlinePlus

    ... review the actual safety data or call the patient’s obstetric provider for suggestions. Web-based information may be found at the websites www.Motherisk.org and www.Reprotox.org . PREVENTION Nonpharmacologic interventions to prevent or treat motion sickness include the ...

  19. Introducing Simple Harmonic Motion.

    ERIC Educational Resources Information Center

    Roche, John

    2002-01-01

    Explains the origin and significance of harmonic motion which is an important topic that has wide application in the world. Describes the phenomenon by using an auxiliary circle to help illustrate the key relationships between acceleration, displacement, time, velocity, and phase. (Contains 16 references.) (Author/YDS)

  20. Theory of orthodontic motions

    NASA Technical Reports Server (NTRS)

    Pepe, S.; Pepe, W. D.; Strauss, A. M.

    1976-01-01

    A general theory of orthodontic motion is developed that can be applied to determine the forces necessary to induce a given tooth to move to the predetermined desirable position. It is assumed that the natural (nonorthodontic) forces may be represented by a periodic function and the orthodontic forces may be superimposed upon the natural forces. A simple expression is derived for the applied stress.

  1. Solar Motion from Australia

    ERIC Educational Resources Information Center

    Treschman, Keith

    2009-01-01

    At noon throughout the year the Sun has a north-south and east-west motion around the meridian. Earliest/latest sunrises and sunsets do not occur at the solstices and the effect is more pronounced with decreasing latitude. This phenomenon is calculated for 25 Australian cities and the following observations are recorded: (1) The latest sunrise…

  2. Wiimote Experiments: Circular Motion

    ERIC Educational Resources Information Center

    Kouh, Minjoon; Holz, Danielle; Kawam, Alae; Lamont, Mary

    2013-01-01

    The advent of new sensor technologies can provide new ways of exploring fundamental physics. In this paper, we show how a Wiimote, which is a handheld remote controller for the Nintendo Wii video game system with an accelerometer, can be used to study the dynamics of circular motion with a very simple setup such as an old record player or a…

  3. Projectile Motion Revisited.

    ERIC Educational Resources Information Center

    Lucie, Pierre

    1979-01-01

    Analyzes projectile motion using symmetry and simple geometry. Deduces the direction of velocity at any point, range, time of flight, maximum height, safety parabola, and maximum range for a projectile launched upon a plane inclined at any angle with respect to the horizontal. (Author/GA)

  4. Marbles in Motion.

    ERIC Educational Resources Information Center

    Brown, Helen; Meyers, Bernice; Schmidt, William

    1999-01-01

    Marbles were successfully used to help primary students develop concepts of motion. Marble-unit activities began with shaking and rattling inference bags and predicting by listening just how many marbles were in each bag. Students made qualitative and quantitative observations of the marbles, manipulated marbles with a partner, and observed…

  5. Wiimote Experiments: Circular Motion

    NASA Astrophysics Data System (ADS)

    Kouh, Minjoon; Holz, Danielle; Kawam, Alae; Lamont, Mary

    2013-03-01

    The advent of new sensor technologies can provide new ways of exploring fundamental physics. In this paper, we show how a Wiimote, which is a handheld remote controller for the Nintendo Wii video game system with an accelerometer, can be used to study the dynamics of circular motion with a very simple setup such as an old record player or a bicycle wheel.

  6. Choosing a Motion Detector.

    ERIC Educational Resources Information Center

    Ballard, David M.

    1990-01-01

    Examines the characteristics of three types of motion detectors: Doppler radar, infrared, and ultrasonic wave, and how they are used on school buses to prevent students from being killed by their own school bus. Other safety devices cited are bus crossing arms and a camera monitor system. (MLF)

  7. A Harmonic Motion Experiment

    ERIC Educational Resources Information Center

    Gluck, P.; Krakower, Zeev

    2010-01-01

    We present a unit comprising theory, simulation and experiment for a body oscillating on a vertical spring, in which the simultaneous use of a force probe and an ultrasonic range finder enables one to explore quantitatively and understand many aspects of simple and damped harmonic motions. (Contains 14 figures.)

  8. Efficient Generation of Dancing Animation Synchronizing with Music Based on Meta Motion Graphs

    NASA Astrophysics Data System (ADS)

    Xu, Jianfeng; Takagi, Koichi; Sakazawa, Shigeyuki

    This paper presents a system for automatic generation of dancing animation that is synchronized with a piece of music by re-using motion capture data. Basically, the dancing motion is synthesized according to the rhythm and intensity features of music. For this purpose, we propose a novel meta motion graph structure to embed the necessary features including both rhythm and intensity, which is constructed on the motion capture database beforehand. In this paper, we consider two scenarios for non-streaming music and streaming music, where global search and local search are required respectively. In the case of the former, once a piece of music is input, the efficient dynamic programming algorithm can be employed to globally search a best path in the meta motion graph, where an objective function is properly designed by measuring the quality of beat synchronization, intensity matching, and motion smoothness. In the case of the latter, the input music is stored in a buffer in a streaming mode, then an efficient search method is presented for a certain amount of music data (called a segment) in the buffer with the same objective function, resulting in a segment-based search approach. For streaming applications, we define an additional property in the above meta motion graph to deal with the unpredictable future music, which guarantees that there is some motion to match the unknown remaining music. A user study with totally 60 subjects demonstrates that our system outperforms the stat-of-the-art techniques in both scenarios. Furthermore, our system improves the synthesis speed greatly (maximal speedup is more than 500 times), which is essential for mobile applications. We have implemented our system on commercially available smart phones and confirmed that it works well on these mobile phones.

  9. Meteoroid streams and comet disintegration

    NASA Astrophysics Data System (ADS)

    Guliyev, A.

    2016-01-01

    The results of the statistical analysis of the dynamic parameters of 114 comets that have undergone nuclear splitting are presented in the article. The list of the objects contains: comets that have split in the period of the observation; data of twin-comets; lost comets with designation D; comets with large-scale structure in the coma. We will describe these comets as "splitted". Some aspects of the following hypothesis are studied: disintegration of comet nuclei happens as the result of their collision with meteoroid streams. For the verification of this hypothesis, the position of splitted comet orbits relatively to 125 meteor streams from Kronk's list is analyzed. It was found that the total number of comet orbit nodes located close to the meteor stream planes (for the distances up to 0.1 AU) is N = 1041. It is shown that if these comets are replaced by randomly selected different comets, N will be reduced by a factor of approximately three.

  10. Dynamic visualization of data streams

    DOEpatents

    Wong, Pak Chung; Foote, Harlan P.; Adams, Daniel R.; Cowley, Wendy E.; Thomas, James J.

    2009-07-07

    One embodiment of the present invention includes a data communication subsystem to receive a data stream, and a data processing subsystem responsive to the data communication subsystem to generate a visualization output based on a group of data vectors corresponding to a first portion of the data stream. The processing subsystem is further responsive to a change in rate of receipt of the data to modify the visualization output with one or more other data vectors corresponding to a second portion of the data stream as a function of eigenspace defined with the group of data vectors. The system further includes a display device responsive to the visualization output to provide a corresponding visualization.

  11. A Robust Streaming Media System

    NASA Astrophysics Data System (ADS)

    Youwei, Zhang

    Presently, application layer multicast protocols (ALM) are proposed as substitute for IP multicast and have made extraordinary achievements. Integrated with Multi-data-stream mode such as Multiple Description Coding (MDC), ALM becomes more scalable and robust in high-dynamic Internet environment compared with single data stream. Although MDC can provide a flexible data transmission style, the synchronization of different descriptions encoded from one video source is proved to be difficult due to different delay on diverse transmission paths. In this paper, an ALM system called HMDC is proposed to improve accepted video quality of streaming media, hosts can join the separate overlay trees in different layers simultaneously, then the maximum synchronized descriptions of the same layer are worked out to acquire the best video quality. Simulations implemented on Internet-like topology indicate that HMDC achieves better video quality, lower link stress, higher robustness and comparable latency compared with traditional ALM protocols.

  12. THE PROPER MOTION OF PALOMAR 5

    SciTech Connect

    Fritz, T. K.; Kallivayalil, N.

    2015-10-01

    Palomar 5 (Pal 5) is a faint halo globular cluster associated with narrow tidal tails. It is a useful system to understand the process of tidal dissolution, as well as to constrain the potential of the Milky Way. A well-determined orbit for Pal 5 would enable detailed study of these open questions. We present here the first CCD-based proper motion measurement of Pal 5 obtained using SDSS as a first epoch and new Large Binocular Telescope/Large Binocular Camera (LBC) images as a second, giving a baseline of 15 years. We perform relative astrometry, using SDSS as a distortion-free reference, and images of the cluster and also of the Pal 5 stream for the derivation of the distortion correction for LBC. The reference frame is made up of background galaxies. We correct for differential chromatic refraction using relations obtained from SDSS colors as well as from flux-calibrated spectra, finding that the correction relations for stars and for galaxies are different. We obtain μ{sub α} = −2.296 ± 0.186 mas yr{sup −1} and μ{sub δ} = −2.257 ± 0.181 mas yr{sup −1} for the proper motion of Pal 5. We use this motion, and the publicly available code galpy, to model the disruption of Pal 5 in different Milky Way models consisting of a bulge, a disk, and a spherical dark matter halo. Our fits to the observed stream properties (streak and radial velocity gradient) result in a preference for a relatively large Pal 5 distance of around 24 kpc. A slightly larger absolute proper motion than what we measure also results in better matches but the best solutions need a change in distance. We find that a spherical Milky Way model, with V{sub 0} = 220 km s{sup −1} and V{sub 20} {sub kpc}, i.e., approximately at the apocenter of Pal 5, of 218 km s{sup −1}, can match the data well, at least for our choice of disk and bulge parametrization.

  13. Development of motion control method for laser soldering process

    SciTech Connect

    Yerganian, S.S.

    1997-05-01

    Development of a method to generate the motion control data for sealing an electronic housing using laser soldering is described. The motion required to move the housing under the laser is a nonstandard application and was performed with a four-axis system using the timed data streaming mode capabilities of a Compumotor AT6400 indexer. A Microsoft Excel 5.0 spreadsheet (named Israuto.xls) was created to calculate the movement of the part under the laser, and macros were written into the spreadsheet to allow the user to easily create this data. A data verification method was developed for simulating the motion data. The geometry of the assembly was generated using Parametric Technology Corporation Pro/E version 15. This geometry was then converted using Pro/DADS version 3.1 from Computer Aided Design Software Inc. (CADSI), and the simulation was carried out using DADS version 8.0 from CADSI.

  14. Plate motion and deformation

    SciTech Connect

    Minster, B.; Prescott, W.; Royden, L.

    1991-02-01

    Our goal is to understand the motions of the plates, the deformation along their boundaries and within their interiors, and the processes that control these tectonic phenomena. In the broadest terms, we must strive to understand the relationships of regional and local deformation to flow in the upper mantle and the rheological, thermal and density structure of the lithosphere. The essential data sets which we require to reach our goal consist of maps of current strain rates at the earth's surface and the distribution of integrated deformation through time as recorded in the geologic record. Our success will depend on the effective synthesis of crustal kinematics with a variety of other geological and geophysical data, within a quantitative theoretical framework describing processes in the earth's interior. Only in this way can we relate the snapshot of current motions and earth structure provided by geodetic and geophysical data with long-term processes operating on the time scales relevant to most geological processes. The wide-spread use of space-based techniques, coupled with traditional geological and geophysical data, promises a revolution in our understanding of the kinematics and dynamics of plate motions over a broad range of spatial and temporal scales and in a variety of geologic settings. The space-based techniques that best address problems in plate motion and deformation are precise space-geodetic positioning -- on land and on the seafloor -- and satellite acquisition of detailed altimetric and remote sensing data in oceanic and continental areas. The overall science objectives for the NASA Solid Earth Science plan for the 1990's, are to Understand the motion and deformation of the lithosphere within and across plate boundaries'', and to understand the dynamics of the mantle, the structure and evolution of the lithosphere, and the landforms that result from local and regional deformation. 57 refs., 7 figs., 2 tabs.

  15. Morphodynamics of supraglacial streams (Invited)

    NASA Astrophysics Data System (ADS)

    Karlstrom, L.; Manga, M.; Gajjar, P.

    2010-12-01

    Supraglacial hydrologic networks exhibit structure and morphodynamics reminiscent of alluvial channels, in an environment where the primary mechanism of erosion is thermal and timescales of topographic adjustment are days to weeks. Supraglacial stream incision is strongly modulated by solar forcing, at times faster or slower than the large-scale lowering of the glacial surface. This variability, in combination with control by structures within the ice or other surface topography, produces a time-evolving drainage network over the course of the melt season. Near the snow line, porous ice facilitates channel development and abandonment via seepage, whereas near the terminus channels are more stable and larger in scale. Discharge generally increases with drainage area, except in cases where water is lost through moulins or crevasses. We report here on fieldwork at the Mendenhall and Llewellyn glaciers on the Juneau Icefield, aimed at better characterizing flow and incision dynamics of supraglacial streams. Time series of temperature, velocity and isotopic composition reveal diurnal variability in flow processes, with clear discharge dependence. GPS profiles show slope dependence of stream sinuousity, and we observe differential incision of ice surface and streams along with downstream migration of meanders and of ice bedforms. We document drainage density, and identify subsurface water movement near the snow line that facilitates channelization. These field measurements are used to develop and validate a theoretical model of meander formation in supraglacial streams, based on the framework of bend theory in alluvial meanders (Karlstrom et al., in review). We find empirically that meandering in supraglacial streams globally follows the linear wavelength-width power law relation found in alluvial and bedrock rivers, but with a smaller intercept. Our linear theory can reproduce this relation, as well as the observed downstream migration of meanders.

  16. Visual Target Tracking in the Presence of Unknown Observer Motion

    NASA Technical Reports Server (NTRS)

    Williams, Stephen; Lu, Thomas

    2009-01-01

    Much attention has been given to the visual tracking problem due to its obvious uses in military surveillance. However, visual tracking is complicated by the presence of motion of the observer in addition to the target motion, especially when the image changes caused by the observer motion are large compared to those caused by the target motion. Techniques for estimating the motion of the observer based on image registration techniques and Kalman filtering are presented and simulated. With the effects of the observer motion removed, an additional phase is implemented to track individual targets. This tracking method is demonstrated on an image stream from a buoy-mounted or periscope-mounted camera, where large inter-frame displacements are present due to the wave action on the camera. This system has been shown to be effective at tracking and predicting the global position of a planar vehicle (boat) being observed from a single, out-of-plane camera. Finally, the tracking system has been extended to a multi-target scenario.

  17. Temperature of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Gulf Stream is one of the strong ocean currents that carries warm water from the sunny tropics to higher latitudes. The current stretches from the Gulf of Mexico up the East Coast of the United States, departs from North America south of the Chesapeake Bay, and heads across the Atlantic to the British Isles. The water within the Gulf Stream moves at the stately pace of 4 miles per hour. Even though the current cools as the water travels thousands of miles, it remains strong enough to moderate the Northern European climate. The image above was derived from the infrared measurements of the Moderate-resolution Imaging Spectroradiometer (MODIS) on a nearly cloud-free day over the east coast of the United States. The coldest waters are shown as purple, with blue, green, yellow, and red representing progressively warmer water. Temperatures range from about 7 to 22 degrees Celsius. The core of the Gulf Stream is very apparent as the warmest water, dark red. It departs from the coast at Cape Hatteras, North Carolina. The cool, shelf water from the north entrains the warmer outflows from the Chesapeake and Delaware Bays. The north wall of the Gulf Stream reveals very complex structure associated with frontal instabilities that lead to exchanges between the Gulf Stream and inshore waters. Several clockwise-rotating warm core eddies are evident north of the core of the Gulf Stream, which enhance the exchange of heat and water between the coastal and deep ocean. Cold core eddies, which rotate counter clockwise, are seen south of the Gulf Stream. The one closest to Cape Hatteras is entraining very warm Gulf Stream waters on its northwest circumference. Near the coast, shallower waters have warmed due to solar heating, while the deeper waters offshore are markedly cooler (dark blue). MODIS made this observation on May 8, 2000, at 11:45 a.m. EDT. For more information, see the MODIS-Ocean web page. The sea surface temperature image was created at the University of Miami using

  18. Collective cell motion in endothelial monolayers

    PubMed Central

    Szabó, A.; Ünnep, R.; Méhes, E.; Twal, W. O.; Argraves, S. W.; Cao, Y.; Czirók, A.

    2011-01-01

    Collective cell motility is an important aspect of several developmental and pathophysiological processes. Despite its importance, the mechanisms that allow cells to be both motile and adhere to one another are poorly understood. In this study we establish statistical properties of the random streaming behavior of endothelial monolayer cultures. To understand the reported empirical findings, we expand the widely used cellular Potts model to include active cell motility. For spontaneous directed motility we assume a positive feedback between cell displacements and cell polarity. The resulting model is studied with computer simulations, and is shown to exhibit behavior compatible with experimental findings. In particular, in monolayer cultures both the speed and persistence of cell motion decreases, transient cell chains move together as groups, and velocity correlations extend over several cell diameters. As active cell motility is ubiquitous both in vitro and in vivo, our model is expected to be a generally applicable representation of cellular behavior. PMID:21076204

  19. Salamander occupancy in headwater stream networks

    USGS Publications Warehouse

    Grant, E.H.C.; Green, L.E.; Lowe, W.H.

    2009-01-01

    1. Stream ecosystems exhibit a highly consistent dendritic geometry in which linear habitat units intersect to create a hierarchical network of connected branches. 2. Ecological and life history traits of species living in streams, such as the potential for overland movement, may interact with this architecture to shape patterns of occupancy and response to disturbance. Specifically, large-scale habitat alteration that fragments stream networks and reduces connectivity may reduce the probability a stream is occupied by sensitive species, such as stream salamanders. 3. We collected habitat occupancy data on four species of stream salamanders in first-order (i.e. headwater) streams in undeveloped and urbanised regions of the eastern U.S.A. We then used an information-theoretic approach to test alternative models of salamander occupancy based on a priori predictions of the effects of network configuration, region and salamander life history. 4. Across all four species, we found that streams connected to other first-order streams had higher occupancy than those flowing directly into larger streams and rivers. For three of the four species, occupancy was lower in the urbanised region than in the undeveloped region. 5. These results demonstrate that the spatial configuration of stream networks within protected areas affects the occurrences of stream salamander species. We strongly encourage preservation of network connections between first-order streams in conservation planning and management decisions that may affect stream species.

  20. Stream-floodwave propagation through the Great Bend alluvial aquifer, Kansas: Field measurements and numerical simulations

    USGS Publications Warehouse

    Sophocleous, M.A.

    1991-01-01

    The hypothesis is explored that groundwater-level rises in the Great Bend Prairie aquifer of Kansas are caused not only by water percolating downward through the soil but also by pressure pulses from stream flooding that propagate in a translatory motion through numerous high hydraulic diffusivity buried channels crossing the Great Bend Prairie aquifer in an approximately west to east direction. To validate this hypothesis, two transects of wells in a north-south and east-west orientation crossing and alongside some paleochannels in the area were instrumented with water-level-recording devices; streamflow data from all area streams were obtained from available stream-gaging stations. A theoretical approach was also developed to conceptualize numerically the stream-aquifer processes. The field data and numerical simulations provided support for the hypothesis. Thus, observation wells located along the shoulders or in between the inferred paleochannels show little or no fluctuations and no correlations with streamflow, whereas wells located along paleochannels show high water-level fluctuations and good correlation with the streamflows of the stream connected to the observation site by means of the paleochannels. The stream-aquifer numerical simulation results demonstrate that the larger the hydraulic diffusivity of the aquifer, the larger the extent of pressure pulse propagation and the faster the propagation speed. The conceptual simulation results indicate that long-distance propagation of stream floodwaves (of the order of tens of kilometers) through the Great Bend aquifer is indeed feasible with plausible stream and aquifer parameters. The sensitivity analysis results indicate that the extent and speed of pulse propagation is more sensitive to variations of stream roughness (Manning's coefficient) and stream channel slope than to any aquifer parameter. ?? 1991.

  1. Riparian influences on stream fish assemblage structure in urbanizing streams

    USGS Publications Warehouse

    Roy, A.H.; Freeman, B.J.; Freeman, Mary C.

    2007-01-01

    We assessed the influence of land cover at multiple spatial extents on fish assemblage integrity, and the degree to which riparian forests can mitigate the negative effects of catchment urbanization on stream fish assemblages. Riparian cover (urban, forest, and agriculture) was determined within 30 m buffers at longitudinal distances of 200 m, 1 km, and the entire network upstream of 59 non-nested fish sampling locations. Catchment and riparian land cover within the upstream network were highly correlated, so we were unable to distinguish between those variables. Most fish assemblage variables were related to % forest and % urban land cover, with the strongest relations at the largest spatial extent of land cover (catchment), followed by riparian land cover in the 1-km and 200-m reach, respectively. For fish variables related to urban land cover in the catchment, we asked whether the influence of riparian land cover on fish assemblages was dependent on the amount of urban development in the catchment. Several fish assemblage metrics (endemic richness, endemic:cosmopolitan abundance, insectivorous cyprinid richness and abundance, and fluvial specialist richness) were all best predicted by single variable models with % urban land cover. However, endemic:cosmopolitan richness, cosmopolitan abundance, and lentic tolerant abundance were related to % forest cover in the 1-km stream reach, but only in streams that had <15% catchment urban land cover. In these cases, catchment urbanization overwhelmed the potential mitigating effects of riparian forests on stream fishes. Together, these results suggest that catchment land cover is an important driver of fish assemblages in urbanizing catchments, and riparian forests are important but not sufficient for protecting stream ecosystems from the impacts of high levels of urbanization.

  2. Controlling acoustic streaming in an ultrasonic heptagonal tweezers with application to cell manipulation.

    PubMed

    Bernassau, A L; Glynne-Jones, P; Gesellchen, F; Riehle, M; Hill, M; Cumming, D R S

    2014-01-01

    Acoustic radiation force has been demonstrated as a method for manipulating micron-scale particles, but is frequently affected by unwanted streaming. In this paper the streaming in a multi-transducer quasi-standing wave acoustic particle manipulation device is assessed, and found to be dominated by a form of Eckart streaming. The experimentally observed streaming takes the form of two main vortices that have their highest velocity in the region where the standing wave is established. A finite element model is developed that agrees well with experimental results, and shows that the Reynolds stresses that give rise to the fluid motion are strongest in the high velocity region. A technical solution to reduce the streaming is explored that entails the introduction of a biocompatible agar gel layer at the bottom of the chamber so as to reduce the fluid depth and volume. By this means, we reduce the region of fluid that experiences the Reynolds stresses; the viscous drag per unit volume of fluid is also increased. Particle Image Velocimetry data is used to observe the streaming as a function of agar-modified cavity depth. It was found that, in an optimised structure, Eckart streaming could be reduced to negligible levels so that we could make a sonotweezers device with a large working area of up to 13 mm × 13 mm.

  3. Oxygen Sag and Stream Purification.

    ERIC Educational Resources Information Center

    Neal, Larry; Herwig, Roy

    1978-01-01

    Presents a literature review of water quality related to oxygen sag and stream purification, covering publications of 1976-77. This review includes: (1) self-purification models; (2) oxygen demand; and (3) reaeration and oxygen transfer. A list of 60 references is also presented. (HM)

  4. POPULATION DECLINE IN STREAM FISH

    EPA Science Inventory

    Over half of the streams in the Mid-Atlantic Highlands have fish communities that are in fair or poor condition, and the EPA concluded that physical habitat alteration represents the greatest potential stressor across this region. A quantitative method for relating habitat quali...

  5. ALIENS IN WESTERN STREAM ECOSYSTEMS

    EPA Science Inventory

    The USEPA's Environmental Monitoring and Assessment Program conducted a five year probability sample of permanent mapped streams in 12 western US states. The study design enables us to determine the extent of selected riparian invasive plants, alien aquatic vertebrates, and some ...

  6. Video Streaming in Online Learning

    ERIC Educational Resources Information Center

    Hartsell, Taralynn; Yuen, Steve Chi-Yin

    2006-01-01

    The use of video in teaching and learning is a common practice in education today. As learning online becomes more of a common practice in education, streaming video and audio will play a bigger role in delivering course materials to online learners. This form of technology brings courses alive by allowing online learners to use their visual and…

  7. Visible Motion Blur

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B. (Inventor); Ahumada, Albert J. (Inventor)

    2014-01-01

    A method of measuring motion blur is disclosed comprising obtaining a moving edge temporal profile r(sub 1)(k) of an image of a high-contrast moving edge, calculating the masked local contrast m(sub1)(k) for r(sub 1)(k) and the masked local contrast m(sub 2)(k) for an ideal step edge waveform r(sub 2)(k) with the same amplitude as r(sub 1)(k), and calculating the measure or motion blur Psi as a difference function, The masked local contrasts are calculated using a set of convolution kernels scaled to simulate the performance of the human visual system, and Psi is measured in units of just-noticeable differences.

  8. Dynamics of Oceanic Motions

    DTIC Science & Technology

    1988-12-31

    Sciences, Harvard University This project researched the dynamics of oceanic motions: aspects of the theory and mod- eling of fundamental dynamical and...84-C-0461 Published 1. Pinardi, N. (1985) Quasigeostrophic Energetics and Oceanic Mesoscale Dynamics, Harvard University , Cambridge, MA (Ph.D. Thesis...Layer Model to the Harvard Quasigeostrophic Model, Harvard University , Cam- bridge, MA (Ph.D. thesis). 15. Robinson, A.R., M.A. Spell and N. Pinardi

  9. Runoff characteristics of California streams

    USGS Publications Warehouse

    Rantz, S.E.

    1972-01-01

    California streams exhibit a wide range of runoff characteristics that are related to the climatologic, topographic, and geologic characteristics of the basins they drain. The annual volume of runoff of a stream, expressed in inches, may be large or small, and daily discharge rates may be highly variable or relatively steady. The bulk of the annual runoff may be storm runoff, or snowmelt runoff, or a combination of both. The streamflow may be ephemeral, intermittent, or perennial; if perennial, base flow may be well sustained or poorly sustained. In this report the various runoff characteristics are identified by numerical index values. They are shown to be related generally to mean annual precipitation, altitude, latitude, and location with respect to the 11 geomorphic provinces in the California Region. With respect to mean annual precipitation on the watershed, streamflow is generally (1) ephemeral if the mean annual precipitation is less than 10 inches, (2) intermittent if the mean annual precipitation is between 10 and 40 inches, and (3) perennial if the mean annual precipitation is more than 40 inches. Departures from those generalizations are associated with (a) the areal variation of such geologic factors as the infiltration and storage capacities of the rocks underlying the watersheds, and (b) the areal variation of evapotranspiration loss as influenced by varying conditions of climate, soil, vegetal cover, and geologic structure. Latitude and altitude determine the proportion of the winter precipitation that will be stored for subsequent runoff in the late spring and summer. In general, if a watershed has at least 30 percent of its area above the normal altitude of the snowline on April 1, it will have significant snowmelt runoff. Snowmelt runoff in California is said to be significant if at least 30 percent of the annual runoff occurs during the 4 months, April through July. Storm runoff is said to be predominant if at least 65 percent of the annual

  10. Pit disassembly motion control

    SciTech Connect

    Christensen, L.; Pittman, P. C.

    2001-01-01

    A Department of Energy (DOE) Pit Disassembly and Conversion Facility (PDCF) is being designed for the Savannah River Site in South Carolina. The facility will recover plutonium from excess nuclear weapon pits defined in START II and START III treaties. The plutonium will be stored and used to produce mixed oxide reactor fuel at another new DOE facility. Because of radiation dose issues, much of the pit disassembly work and material transfer will be automated. Automated material handling systems will interface with disassembly lathes, conversion reactors that produce oxide for storage, robotic container welding stations, vault retrieval systems, and nondestructive assay (NDA) instrumentation. The goal is to use common motion control hardware for material transfer and possibly common motion controllers for the unique PDCF systems. The latter is complicated by the different directions manufactures are considering for distributed control, such as Firewire, SERCOS, etc., and by the unique control requirements of machines such as lathes compared to controls for an integrated NDA system. The current design approach is to standardize where possible, use network cables to replace wire bundles where possible, but to first select hardware and motion controllers that meet specific machine or process requirements.

  11. Effects of Stream Channel Characteristics on Nitrate Delivery to Streams and In-Stream Denitrification Rates, Raccoon River, Iowa

    NASA Astrophysics Data System (ADS)

    Prestegaard, K. L.; O'Connell, M.

    2004-05-01

    Streams in agricultural areas often exhibit significant channel and sediment modifications; they are often incised and transport more fine sediment than non-agricultural streams. These channel characteristics can influence stream water quality by modifying surface-groundwater interactions. In the Raccoon River basin, channel incision increases the delivery of nitrate from the groundwater to the streams. The sandy in-stream sediments, however, serve as very effective sites for in-stream denitrification. Nitrate delivery and in-stream denitrification was examined in 3 subwatersheds of the Raccoon River. Stream morphology, water quality, and sediment characteristics were measured at 35 sites with varying land uses. Headwater stream nitrate concentration increased with percent row crops and the amount of channel incision. Downstream sites showed a wide variation in nitrate concentration with land use. Stream nitrate concentrations were measured at 6 sites in each of 3 streams with high percentages of row crop land uses during high summer baseflow following the 1993 floods and during average summer baseflow in 1995. Nitrate concentrations were systematically higher for the high baseflow conditions of 1993 than the average year (1995). This change in nitrate concentration is interpreted as the increased effectiveness of nitrate delivery to the stream during periods of high water tables. The effect was most pronounced in incised reaches. All 3 streams show downstream decreases in nitrate concentration. Water samples for all the sites in the watersheds were analyzed for nitrogen isotopic composition. The nitrogen isotopic composition shifts with towards higher d 15N values with decreasing nitrate concentration. This is consistent with denitrification reactions that selectively remove the 14N leaving a higher proportion of 15N in the nitrate. This suggests that most of the downstream decrease in nitrate concentrations is a result of in-stream denitrification. The high rates

  12. Dynamical Modelling of Meteoroid Streams

    NASA Astrophysics Data System (ADS)

    Clark, David; Wiegert, P. A.

    2012-10-01

    Accurate simulations of meteoroid streams permit the prediction of stream interaction with Earth, and provide a measure of risk to Earth satellites and interplanetary spacecraft. Current cometary ejecta and meteoroid stream models have been somewhat successful in predicting some stream observations, but have required questionable assumptions and significant simplifications. Extending on the approach of Vaubaillon et al. (2005)1, we model dust ejection from the cometary nucleus, and generate sample particles representing bins of distinct dynamical evolution-regulating characteristics (size, density, direction, albedo). Ephemerides of the sample particles are integrated and recorded for later assignment of frequency based on model parameter changes. To assist in model analysis we are developing interactive software to permit the “turning of knobs” of model parameters, allowing for near-real-time 3D visualization of resulting stream structure. With this tool, we will revisit prior assumptions made, and will observe the impact of introducing non-uniform cometary surface attributes and temporal activity. The software uses a single model definition and implementation throughout model verification, sample particle bin generation and integration, and analysis. It supports the adjustment with feedback of both independent and independent model values, with the intent of providing an interface supporting multivariate analysis. Propagations of measurement uncertainties and model parameter precisions are tracked rigorously throughout. We maintain a separation of the model itself from the abstract concepts of model definition, parameter manipulation, and real-time analysis and visualization. Therefore we are able to quickly adapt to fundamental model changes. It is hoped the tool will also be of use in other solar system dynamics problems. 1 Vaubaillon, J.; Colas, F.; Jorda, L. (2005) A new method to predict meteor showers. I. Description of the model. Astronomy and

  13. Indiana stream-temperature characteristics

    USGS Publications Warehouse

    Shampine, W.J.

    1977-01-01

    Periodic stream-temperature data have been collected at 280 different sites in Indiana by the U.S. Geological Survey and the Indiana State Board of Health. These data have been analyzed using a simple-harmonic curve-fitting procedure. When the equation coefficients are known, calculations can be made for a given stream to estimate the maximum and minimum temperatures, the temperature on a given day, the day a given temperature is expected, or the length of time temperatures will exceed, or be less than, a specific. The calculated harmonic coefficients were related to 23 topographic, basin, and climatic characteristics, and were analyzed by multiple-regression analysis techniques. The regional regression analysis for the harmonic- mean stream temperature, M, resulted in the following arithmetic function of station latitude (LAT). M = 41.36 - 0.7166 (LAT) The multiple correlation coefficient (r) was .72. Poor correlations were found for the harmonic phase-angle and amplitude coefficients, C and A, respectively. Constants of 4.32 radians for C and 11.27° Celsius for A are suggested as average statewide values in Indiana streams. The mean temperature of the White River at Indianapolis was raised 3.5° Celsius above expected ambient levels caused by climatic conditions alone, primarily as a result of discharges from powerplants. In general, the harmonic coefficients depicting annual variability in stream temperatures, generated from the Indiana State board of Health data collected every 2 weeks, are the same as coefficients generated from the U.S. Geological Survey date collected every 4-6 weeks.

  14. Efficient stream distributions in radiative transfer theory

    NASA Technical Reports Server (NTRS)

    Whitney, C.

    1974-01-01

    This paper discusses a new, computationally-efficient method for approximating the integro-differential equation of radiative transfer with a finite set of coupled differential equations for discrete streams. The method uses recommended spatial distributions of streams that are quite different from those typically used in that they are based on the symmetry of several regular Platonic solids. To facilitate the use of such distributions, an explicit, one-parameter relationship between the physical radiance and the abstract stream is formulated. The parameter is used to determine the minimum number of streams required in the radiative transfer model. Accuracy and computational efficiency are shown to be served best by choosing a stream distribution that is invariant to a large number of three space rotations. For various values of the above-mentioned parameter, the resulting recommended stream distribution is shown to be more computationally efficient than more conventional stream distributions. Finally, the incorporation of polarization in the stream definition is described.

  15. Stream Tables and Watershed Geomorphology Education.

    ERIC Educational Resources Information Center

    Lillquist, Karl D.; Kinner, Patricia W.

    2002-01-01

    Reviews copious stream tables and provides a watershed approach to stream table exercises. Results suggest that this approach to learning the concepts of fluvial geomorphology is effective. (Contains 39 references.) (DDR)

  16. Cytoplasmic Streaming in the Drosophila Oocyte.

    PubMed

    Quinlan, Margot E

    2016-10-06

    Objects are commonly moved within the cell by either passive diffusion or active directed transport. A third possibility is advection, in which objects within the cytoplasm are moved with the flow of the cytoplasm. Bulk movement of the cytoplasm, or streaming, as required for advection, is more common in large cells than in small cells. For example, streaming is observed in elongated plant cells and the oocytes of several species. In the Drosophila oocyte, two stages of streaming are observed: relatively slow streaming during mid-oogenesis and streaming that is approximately ten times faster during late oogenesis. These flows are implicated in two processes: polarity establishment and mixing. In this review, I discuss the underlying mechanism of streaming, how slow and fast streaming are differentiated, and what we know about the physiological roles of the two types of streaming.

  17. Stream Gauges and Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Alsdorf, D. E.

    2010-12-01

    Satellite measurements should not be viewed as a replacement for stream gauges. However, occasionally it is suggested that because satellite-based measurements can provide river discharge, a motivation for satellite approaches is an increasing lack of stream gauges. This is an argument for more stream gauges, but not necessarily for satellite measurements. Rather, in-situ and spaceborne methods of estimating discharge are complementary. Stream gauges provide frequent measurements at one point in the river reach whereas satellites have the potential to measure throughout all reaches but at orbital repeat intervals of days to weeks. The Surface Water and Ocean Topography satellite mission (SWOT) is an opportunity to further develop these complements. The motivation for SWOT, and indeed for any satellite based method of estimating discharge, should not be as a replacement for stream gauges. Scientific and application uses should motivate the measurements. For example, understanding floods with their dynamic water surfaces are best sampled from remote platforms that provide water surface elevations throughout the floodwave. As another example, today’s water and energy balance models are giving outputs at increasing spatial resolution and are making use of water surface elevations throughout the modeled basin. These models require a similar resolution in the calibrating and validating observations. We should also be aware of practical limitations. In addition to providing spatially distributed hydrodynamic measurements on rivers, SWOT will be able to measure storage changes in the estimated 30 million lakes in the world that are larger than a hectare. Knowing the storage changes in these lakes is especially important in certain regions such as the Arctic but gauging even a small fraction of these is impractical. Another motivator for satellite methods is that even in the presence of stream gauges, discharge data is not always well shared throughout all countries

  18. EDITORIAL: Nanotechnology in motion Nanotechnology in motion

    NASA Astrophysics Data System (ADS)

    Demming, Anna

    2012-02-01

    , Toshio Ando from the University of Kanazawa provides an overview of developments that have allowed atomic force microscopy to move from rates of the order of one frame a minute to over a thousand frames per second in constant height mode, as reported by Mervyn Miles and colleagues at Bristol University and University College London [8]. Among the pioneers in the field, Ando's group demonstrated the ability to record the Brownian motion of myosin V molecules on mica with image capture rates of 100 x 100 pixels in 80 ms over a decade ago [9]. The developments unleash the potential of atomic force microscopy to observe the dynamics of biological and materials systems. If seeing is believing, the ability to present real motion pictures of the nanoworld cannot fail to capture the public imagination and stimulate burgeoning new avenues of scientific endeavour. Nearly 350 years on from the publication Micrographia, images in microscopy have moved from the page to the movies. References [1] Binnig G, Quate C F, and Gerber Ch 1986 Phys. Rev. Lett. 56 930-3 [2] Ando T 2012 Nanotechnology 23 062001 [3] J G 1934 Nature 134 635-6 [4] Bharadwaj P, Anger P and Novotny L 2007 Nanotechnology 18 044017 [5] The Nobel Prize in Physics 1986 Nobelprize.org [6] Kim K K, Reina A, Shi Y, Park H, Li L-J, Lee Y H and Kong J 2010 Nanotechnology 21 285205 [7] Phillips D B, Grieve J A, Olof S N, Kocher S J, Bowman R, Padgett M J, Miles M J and Carberry D M 2011 Nanotechnology 22 285503 [8] Picco L M, Bozec L, Ulcinas A, Engledew D J, Antognozzi M, Horton M A and Miles M J 2007 Nanotechnology 18 044030 [9] Ando T, Kodera N, Takai E, Maruyama D, Saito K and Toda A 2001 Proc. Natl. Acad. Sci. 98 12468

  19. Olefin Recovery from Chemical Industry Waste Streams

    SciTech Connect

    A.R. Da Costa; R. Daniels; A. Jariwala; Z. He; A. Morisato; I. Pinnau; J.G. Wijmans

    2003-11-21

    The objective of this project was to develop a membrane process to separate olefins from paraffins in waste gas streams as an alternative to flaring or distillation. Flaring these streams wastes their chemical feedstock value; distillation is energy and capital cost intensive, particularly for small waste streams.

  20. Maximizing Resource Utilization in Video Streaming Systems

    ERIC Educational Resources Information Center

    Alsmirat, Mohammad Abdullah

    2013-01-01

    Video streaming has recently grown dramatically in popularity over the Internet, Cable TV, and wire-less networks. Because of the resource demanding nature of video streaming applications, maximizing resource utilization in any video streaming system is a key factor to increase the scalability and decrease the cost of the system. Resources to…

  1. The Stream Table in Physical Geography Instruction.

    ERIC Educational Resources Information Center

    Wikle, Thomas A.; Lightfoot, Dale R.

    1997-01-01

    Outlines a number of activities to be conducted with a stream table (large wooden box filled with sediment and designed for water to pass through) in class. Activities illustrate such fluvial processes as stream meandering, erosion, transportation, and deposition. Includes a diagram for constructing a stream table. (MJP)

  2. Academic Self-Concepts in Ability Streams: Considering Domain Specificity and Same-Stream Peers

    ERIC Educational Resources Information Center

    Liem, Gregory Arief D.; McInerney, Dennis M.; Yeung, Alexander S.

    2015-01-01

    The study examined the relations between academic achievement and self-concepts in a sample of 1,067 seventh-grade students from 3 core ability streams in Singapore secondary education. Although between-stream differences in achievement were large, between-stream differences in academic self-concepts were negligible. Within each stream, levels of…

  3. Where Did All the Streams Go? Effects of Urbanization on Hydrologic Permanence of Headwater Streams

    EPA Science Inventory

    Headwater streams represent a majority (up to 70%) of the stream length in the United States; however, these small streams are often piped or filled to accommodate residential, commercial, and industrial development. Legal protection of headwater streams under the Clean Water Ac...

  4. Assessing Stream Bed Stability and Excess Sedimentation in Mountain Streams

    NASA Astrophysics Data System (ADS)

    Faustini, J. M.; Kaufmann, P. R.

    2002-12-01

    Land use and resource exploitation in headwaters catchments, such as logging, mining, and road building, often increase sediment supply to streams, potentially causing excess sedimentation. Decreases in mean substrate size and increases in fine stream bed sediments can lead to increased frequency of bed scour, while accumulation of fine sediments in the interstices of coarse bed particles can adversely impact salmon spawning habitat and reduce habitat availability for benthic organisms. We are testing an index of relative bed stability (RBS), based on reach-scale synoptic stream surveys, that is calculated as the ratio of the observed geometric mean particle diameter to the estimated critical diameter at bankfull flow after adjusting for shear stress losses due to channel morphology and large woody debris (LWD). We hypothesize that in watersheds not altered by human disturbances, transport capacity should be in rough equilibrium with sediment supply and RBS should be close to unity. In streams where human activity has substantially augmented sediment supply, we expect that textural fining may occur, leading to lower RBS values. However, downstream trends of decreasing slope and particle size and increasing sediment supply might lead to systematic downstream trends in RBS, and variations in local channel characteristics could cause variability in calculated RBS values. To test whether RBS is useful as an indicator of textural fining in response to anthropogenic disturbance, we sampled streams in watersheds spanning a wide range of disturbance intensity (high, medium and low) in two sub-regions of contrasting lithology in the northern Coast Range of Oregon and in the mid-Atlantic U.S. In each watershed we sampled 3 closely-spaced main stem reaches (30-50 km2 drainage area) and 3 reaches in one or more smaller tributaries (5-10 km2) to assess local variability and within-basin longitudinal trends in RBS relative to variation between watersheds with different land use

  5. Autoadaptive motion modelling for MR-based respiratory motion estimation.

    PubMed

    Baumgartner, Christian F; Kolbitsch, Christoph; McClelland, Jamie R; Rueckert, Daniel; King, Andrew P

    2017-01-01

    Respiratory motion poses significant challenges in image-guided interventions. In emerging treatments such as MR-guided HIFU or MR-guided radiotherapy, it may cause significant misalignments between interventional road maps obtained pre-procedure and the anatomy during the treatment, and may affect intra-procedural imaging such as MR-thermometry. Patient specific respiratory motion models provide a solution to this problem. They establish a correspondence between the patient motion and simpler surrogate data which can be acquired easily during the treatment. Patient motion can then be estimated during the treatment by acquiring only the simpler surrogate data. In the majority of classical motion modelling approaches once the correspondence between the surrogate data and the patient motion is established it cannot be changed unless the model is recalibrated. However, breathing patterns are known to significantly change in the time frame of MR-guided interventions. Thus, the classical motion modelling approach may yield inaccurate motion estimations when the relation between the motion and the surrogate data changes over the duration of the treatment and frequent recalibration may not be feasible. We propose a novel methodology for motion modelling which has the ability to automatically adapt to new breathing patterns. This is achieved by choosing the surrogate data in such a way that it can be used to estimate the current motion in 3D as well as to update the motion model. In particular, in this work, we use 2D MR slices from different slice positions to build as well as to apply the motion model. We implemented such an autoadaptive motion model by extending our previous work on manifold alignment. We demonstrate a proof-of-principle of the proposed technique on cardiac gated data of the thorax and evaluate its adaptive behaviour on realistic synthetic data containing two breathing types generated from 6 volunteers, and real data from 4 volunteers. On synthetic data

  6. HDS: a fast and hierarchical diamond search algorithm in video motion estimation

    NASA Astrophysics Data System (ADS)

    Gong, Sheng-rong; Zhou, Xiang

    2005-10-01

    As the development of the Internet and communication technology, video coding has been more and more important. When the rate of video transmission is high, the correlation between adjacent video frames is high, too. The cost of coding the difference of the frames is litter than that of coding directly video frames. So, when video streams are coding, motion estimation is usually used to reduce the correlation between video streams in temporal axes. Therefore, motion estimation plays an important role in video coding. The present Diamond Search is accepted as one of the most efficient quick search. In this paper, a new motion estimation based on analysis of Diamond Search is proposed, in which video frames fall into two categories: the violent-motion frames and the moderate-motion frames. Based on the new motion estimation method, a quick hierarchical diamond search algorithm is proposed for the majority of moderate-motion frames. The experimental results have showed that the proposed algorithm is much faster than Diamond Search and obtains the same image quality.

  7. Human motion analysis and modeling

    NASA Astrophysics Data System (ADS)

    Prussing, Keith; Cathcart, J. Michael; Kocher, Brian

    2011-06-01

    Georgia Tech has investigated methods for the detection and tracking of personnel in a variety of acquisition environments. This research effort focused on a detailed phenomenological analysis of human physiology and signatures with the subsequent identification and characterization of potential observables. As a fundamental part of this research effort, Georgia Tech collected motion capture data on an individual for a variety of walking speeds, carrying loads, and load distributions. These data formed the basis for deriving fundamental properties of the individual's motion and supported the development of a physiologically-based human motion model. Subsequently this model aided the derivation and analysis of motion-based observables, particularly changes in the motion of various body components resulting from load variations. This paper will describe the data acquisition process, development of the human motion model, and use of the model in the observable analysis. Video sequences illustrating the motion data and modeling results will also be presented.

  8. GROUND MOTION ASSESSMENT BASED ON WEAK MOTION DATA IN TAIWAN Ground Motion Assessment Based on Weak Motion Data in Taiwan

    NASA Astrophysics Data System (ADS)

    Akinci, A.; D'Amico, S.; Malagnini, L.

    2010-12-01

    In this study, we characterize the scaling of the ground motions for frequencies ranging between 0.25 and 5 Hz, obtaining results for seismic attenuation, geometrical spreading, and source parameters in Taiwan. We regressed this large number of weak-motion data in order to characterize the regional propagation and the absolute source scaling. Stochastic simulations are generated for finite-fault ruptures using the obtained parameters to predict the absolute peaks of the ground acceleration and velocity for several magnitude and distance range, as well as beyond the magnitude range of the weak-motion data set on which they are calculated. The predictions are then compared with recorded strong motion data and empirical ground motion prediction equation obtained for the study region. We showed that our regional parameters, obtained from independent weak-motion database, may be applied for evaluation of ground motion parameters for earthquakes of magnitude up to 7.6.

  9. Rotational motion of Vesta

    NASA Astrophysics Data System (ADS)

    Rambaux, N.; Asmar, S. W.; Konopliv, A. S.

    2012-09-01

    Vesta is the second most massive body of the asteroid belt and contains a giant impact and a differentiated interior. Constraints on internal structure can be inferred from various observations such as gravity field measurements [1]. Especially, detailed knowledge of the rotational motion can help constrain the mass distribution inside the body, which in turn can lead to information on its history. Here, we compute the polar motion, precession-nutation, and length-of-day variations of Vesta. The Vesta's Pole position in space has been obtained by Dawn mission [1] and the orbital pole of Vesta at J2000 can be obtained from the Horizons ephemerides [2]. The obliquity, defined as the angle between the normal to the orbital plane and the figure axis, brings information on the moment of inertia if it has reached its equilibrium position [3], the present value from observations is around 27 degrees. That is far from the ˜ 0.03 deg expected for the equilibrium position. In addition, the required timescale to fully damped the obliquity appears to be very long following the same approach developed in [4]. Thus, it appears that the obliquity of Vesta has not yet relaxed in its Cassini state. The figure of Vesta appears to be triaxial and the Sun exerts a non-zero torque. By following the approach developed for the Earth [e.g. 5] and Ceres [4], we compute the nutation of Vesta. The nutational motion of Vesta is dominated by the semi-annual nutation (996 milli-arcseconds or 1.26 m surface displacement) related to the large obliquity of Vesta, and then terms related to harmonics and also to the planet's mean longitude. The detection of such small displacement requires tracking of Vesta's surface with high precision. The precession time of the axis of Vesta is very long, about 179,000 years.

  10. Optimising rigid motion compensation for small animal brain PET imaging

    NASA Astrophysics Data System (ADS)

    Spangler-Bickell, Matthew G.; Zhou, Lin; Kyme, Andre Z.; De Laat, Bart; Fulton, Roger R.; Nuyts, Johan

    2016-10-01

    Motion compensation (MC) in PET brain imaging of awake small animals is attracting increased attention in preclinical studies since it avoids the confounding effects of anaesthesia and enables behavioural tests during the scan. A popular MC technique is to use multiple external cameras to track the motion of the animal’s head, which is assumed to be represented by the motion of a marker attached to its forehead. In this study we have explored several methods to improve the experimental setup and the reconstruction procedures of this method: optimising the camera-marker separation; improving the temporal synchronisation between the motion tracker measurements and the list-mode stream; post-acquisition smoothing and interpolation of the motion data; and list-mode reconstruction with appropriately selected subsets. These techniques have been tested and verified on measurements of a moving resolution phantom and brain scans of an awake rat. The proposed techniques improved the reconstructed spatial resolution of the phantom by 27% and of the rat brain by 14%. We suggest a set of optimal parameter values to use for awake animal PET studies and discuss the relative significance of each parameter choice.

  11. Optimised motion tracking for positron emission tomography studies of brain function in awake rats.

    PubMed

    Kyme, Andre Z; Zhou, Victor W; Meikle, Steven R; Baldock, Clive; Fulton, Roger R

    2011-01-01

    Positron emission tomography (PET) is a non-invasive molecular imaging technique using positron-emitting radioisotopes to study functional processes within the body. High resolution PET scanners designed for imaging rodents and non-human primates are now commonplace in preclinical research. Brain imaging in this context, with motion compensation, can potentially enhance the usefulness of PET by avoiding confounds due to anaesthetic drugs and enabling freely moving animals to be imaged during normal and evoked behaviours. Due to the frequent and rapid motion exhibited by alert, awake animals, optimal motion correction requires frequently sampled pose information and precise synchronisation of these data with events in the PET coincidence data stream. Motion measurements should also be as accurate as possible to avoid degrading the excellent spatial resolution provided by state-of-the-art scanners. Here we describe and validate methods for optimised motion tracking suited to the correction of motion in awake rats. A hardware based synchronisation approach is used to achieve temporal alignment of tracker and scanner data to within 10 ms. We explored the impact of motion tracker synchronisation error, pose sampling rate, rate of motion, and marker size on motion correction accuracy. With accurate synchronisation (<100 ms error), a sampling rate of >20 Hz, and a small head marker suitable for awake animal studies, excellent motion correction results were obtained in phantom studies with a variety of continuous motion patterns, including realistic rat motion (<5% bias in mean concentration). Feasibility of the approach was also demonstrated in an awake rat study. We conclude that motion tracking parameters needed for effective motion correction in preclinical brain imaging of awake rats are achievable in the laboratory setting. This could broaden the scope of animal experiments currently possible with PET.

  12. Motion analysis report

    NASA Technical Reports Server (NTRS)

    Badler, N. I.

    1985-01-01

    Human motion analysis is the task of converting actual human movements into computer readable data. Such movement information may be obtained though active or passive sensing methods. Active methods include physical measuring devices such as goniometers on joints of the body, force plates, and manually operated sensors such as a Cybex dynamometer. Passive sensing de-couples the position measuring device from actual human contact. Passive sensors include Selspot scanning systems (since there is no mechanical connection between the subject's attached LEDs and the infrared sensing cameras), sonic (spark-based) three-dimensional digitizers, Polhemus six-dimensional tracking systems, and image processing systems based on multiple views and photogrammetric calculations.

  13. Space motion sickness

    NASA Technical Reports Server (NTRS)

    Vanderploeg, J. M.; Stewart, D. F.; Davis, J. R.

    1986-01-01

    Space motion sickness clinical characteristics, time course, prediction of susceptibility, and effectiveness of countermeasures were evaluated. Although there is wide individual variability, there appear to be typical patterns of symptom development. The duration of symptoms ranges from several hours to four days with the majority of individuals being symptom free by the end of third day. The etiology of this malady remains uncertain but evidence points to reinterpretation of otolith inputs as being a key factor in the response of the neurovestibular system. Prediction of susceptibility and severity remains unsatisfactory. Countermeasures tried include medications, preflight adaptation, and autogenic feedback training. No countermeasure is entirely successful in eliminating or alleviating symptoms.

  14. Motion dynamics of submersibles

    NASA Astrophysics Data System (ADS)

    Kalske, Seppo

    1991-04-01

    A literature survey of motion dynamics of subsea vehicles of a general shape was performed. Hydrodynamic tests were carried out with an existing tethered remotely operated vehicle and with its full scale model. The experiments give data of maneuvering capabilities, and of hydrodynamic characteristics of small subsea vehicles. A simulation method was developed on this basis to compute the vehicle trajectory in the time domain as a function of different control commands. The method can be applied to any subsea vehicle controlled by thruster units.

  15. Thermal loading of natural streams

    USGS Publications Warehouse

    Jackman, Alan P.; Yotsukura, Nobuhiro

    1977-01-01

    The impact of thermal loading on the temperature regime of natural streams is investigated by mathematical models, which describe both transport (convection-diffusion) and decay (surface dissipation) of waste heat over 1-hour or shorter time intervals. The models are derived from the principle of conservation of thermal energy for application to one- and two-dimensional spaces. The basic concept in these models is to separate water temperature into two parts, (1) excess temperature due to thermal loading and (2) natural (ambient) temperature. This separation allows excess temperature to be calculated from the models without incoming radiation data. Natural temperature may either be measured in prototypes or calculated from the model. If use is made of the model, however, incoming radiation is required as input data. Comparison of observed and calculated temperatures in seven natural streams shows that the models are capable of predicting transient temperature regimes satisfactorily in most cases. (Woodard-USGS)

  16. Metamers of the ventral stream

    PubMed Central

    Freeman, Jeremy; Simoncelli, Eero P.

    2011-01-01

    The human capacity to recognize complex visual patterns emerges in a sequence of brain areas known as the ventral stream, beginning with primary visual cortex (V1). We develop a population model for mid-ventral processing, in which non-linear combinations of V1 responses are averaged within receptive fields that grow with eccentricity. To test the model, we generate novel forms of visual metamers — stimuli that differ physically, but look the same. We develop a behavioral protocol that uses metameric stimuli to estimate the receptive field sizes in which the model features are represented. Because receptive field sizes change along the ventral stream, the behavioral results can identify the visual area corresponding to the representation. Measurements in human observers implicate V2, providing a new functional account of this area. The model explains deficits of peripheral vision known as “crowding”, and provides a quantitative framework for assessing the capabilities of everyday vision. PMID:21841776

  17. Design Automation for Streaming Systems

    DTIC Science & Technology

    2005-12-16

    AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14 . ABSTRACT RTL design methodologies are struggling to...transistor systems— AMD Athlon 64 X2: 233M transistors [Mitchell, 2005], IBM Cell: 241M transistors [Gschwind et al., 2005], nVidia GeForce 7800 GTX: 302M...buffers may be chosen by a compiler to match the resources 14 Chapter 1. Introduction of the target device. A small stream buffer might be implemented

  18. Functional Objectives for Stream Restoration

    DTIC Science & Technology

    2006-09-01

    waterways but do not relate directly to their social context, which is addressed later in the category of beneficial uses. The basic functions that...ecological, economic, or social . Indicators and measures for the primary functions identified in the previous section are summarized in Tables 2...through 6. Beneficial Uses Perspective The social aspects of stream and riparian ecosystems are addressed in this report as beneficial uses. Uses are

  19. Stream biogeochemical and suspended sediment responses to permafrost degradation in stream banks in Taylor Valley, Antarctica

    NASA Astrophysics Data System (ADS)

    Gooseff, Michael N.; Van Horn, David; Sudman, Zachary; McKnight, Diane M.; Welch, Kathleene A.; Lyons, William B.

    2016-03-01

    Stream channels in the McMurdo Dry Valleys are characteristically wide, incised, and stable. At typical flows, streams occupy a fraction of the oversized channels, providing habitat for algal mats. In January 2012, we discovered substantial channel erosion and subsurface thermomechanical erosion undercutting banks of the Crescent Stream. We sampled stream water along the impacted reach and compared concentrations of solutes to the long-term data from this stream ( ˜ 20 years of monitoring). Thermokarst-impacted stream water demonstrated higher electrical conductivity, and concentrations of chloride, sulfate, sodium, and nitrate than the long-term medians. These results suggest that this mode of lateral permafrost degradation may substantially impact stream solute loads and potentially fertilize stream and lake ecosystems. The potential for sediment to scour or bury stream algal mats is yet to be determined, though it may offset impacts of associated increased nutrient loads to streams.

  20. Development of sensitivity to global form and motion in macaque monkeys (Macaca nemestrina).

    PubMed

    Kiorpes, Lynne; Price, Tracy; Hall-Haro, Cynthia; Movshon, J Anthony

    2012-06-15

    To explore the relative development of the dorsal and ventral extrastriate processing streams, we studied the development of sensitivity to form and motion in macaque monkeys (Macaca nemestrina). We used Glass patterns and random dot kinematograms (RDK) to assay ventral and dorsal stream function, respectively. We tested 24 animals, longitudinally or cross-sectionally, between the ages of 5 weeks and 3 years. Each animal was tested with Glass patterns and RDK stimuli with each of two pattern types--circular and linear--at each age using a two alternative forced-choice task. We measured coherence threshold for discrimination of the global form or motion pattern from an incoherent control stimulus. Sensitivity to global motion appeared earlier than to global form and was higher at all ages, but performance approached adult levels at similar ages. Infants were most sensitive to large spatial scale (Δx) and fast speeds; sensitivity to fine scale and slow speeds developed more slowly independently of pattern type. Within the motion domain, pattern type had little effect on overall performance. However, within the form domain, sensitivity for linear Glass patterns was substantially poorer than that for concentric patterns. Our data show comparatively early onset for global motion integration ability, perhaps reflecting early development of the dorsal stream. However, both pathways mature over long time courses reaching adult levels between 2 and 3 years after birth.

  1. Animal models for auditory streaming.

    PubMed

    Itatani, Naoya; Klump, Georg M

    2017-02-19

    Sounds in the natural environment need to be assigned to acoustic sources to evaluate complex auditory scenes. Separating sources will affect the analysis of auditory features of sounds. As the benefits of assigning sounds to specific sources accrue to all species communicating acoustically, the ability for auditory scene analysis is widespread among different animals. Animal studies allow for a deeper insight into the neuronal mechanisms underlying auditory scene analysis. Here, we will review the paradigms applied in the study of auditory scene analysis and streaming of sequential sounds in animal models. We will compare the psychophysical results from the animal studies to the evidence obtained in human psychophysics of auditory streaming, i.e. in a task commonly used for measuring the capability for auditory scene analysis. Furthermore, the neuronal correlates of auditory streaming will be reviewed in different animal models and the observations of the neurons' response measures will be related to perception. The across-species comparison will reveal whether similar demands in the analysis of acoustic scenes have resulted in similar perceptual and neuronal processing mechanisms in the wide range of species being capable of auditory scene analysis.This article is part of the themed issue 'Auditory and visual scene analysis'.

  2. Tidal streams in triaxial systems

    NASA Astrophysics Data System (ADS)

    Price-Whelan, Adrian M.; Johnston, Kathryn V.; Pearson, Sarah; Kupper, Andreas Hans Wilhelm

    2015-01-01

    Tidal streams form from the steady disruption of stellar systems orbiting within the gravitational field of some parent galaxy. Many streams and debris structures have been discovered in the halo of the Milky Way and have been used to model the potential of the Galaxy. However, few of these models have yet explored the properties of tidal debris in triaxial potentials. The existence of a variety of orbits, resonances, and chaotic regions in such potentials suggest that the morphologies and dispersal timescales of debris could differ significantly from the simpler spherical and oblate cases. In this work we use a series of N-body simulations of stellar systems over a range of masses of disruption in triaxial potentials to understand the influence of the nature and types of orbits on debris morphologies. Our results suggest that the mere existence of the multitude of thin streams already known to orbit the Milky Way provides significant constraints on the classes of triaxial potentials that provide a good representation for its dark matter halo.

  3. Streaming potential of superhydrophobic microchannels.

    PubMed

    Park, Hung Mok; Kim, Damoa; Kim, Se Young

    2017-03-01

    For the purpose of gaining larger streaming potential, it has been suggested to employ superhydrophobic microchannels with a large velocity slip. There are two kinds of superhydrophobic surfaces, one having a smooth wall with a large Navier slip coefficient caused by the hydrophobicity of the wall material, and the other having a periodic array of no- shear slots of air pockets embedded in a nonslip wall. The electrokinetic flows over these two superhydrophobic surfaces are modelled using the Navier-Stokes equation and convection-diffusion equations of the ionic species. The Navier slip coefficient of the first kind surfaces and the no-shear slot ratio of the second kind surfaces are similar in the sense that the volumetric flow rate increases as these parameter values increase. However, although the streaming potential increases monotonically with respect to the Navier slip coefficient, it reaches a maximum and afterward decreases as the no-shear ratio increases. The results of the present investigation imply that the characterization of superhydrophobic surfaces employing only the measurement of volumetric flow rate against pressure drop is not appropriate and the fine structure of the superhydrophobic surfaces must be verified before predicting the streaming potential and electrokinetic flows accurately.

  4. Fronto-temporal regions encode the manner of motion in spatial language

    PubMed Central

    Quandt, Lorna C.; Cardillo, Eileen R.; Kranjec, Alexander; Chatterjee, Anjan

    2015-01-01

    When describing spatial events, dynamic actions can be decomposed into the path of motion (where the object moves), and the manner of motion (how the object moves). These components may be instantiated in two processing streams in the human brain, wherein dorsal parietal areas process path-related information, while ventral temporal regions process manner information. Previous research showed this pattern during the observation of videos showing animate characters in motion [15] It is unknown whether reading language describing path and manner information—a level of abstraction beyond the perception of visual motion—relies on similar mechanisms. Here, we use functional neuroimaging to show that the left pMTG processes the manner of motion during reading. We also demonstrate the involvement of other ventral fronto-temporal regions in the understanding of manner of motion in spatial language. PMID:26493606

  5. Lateral inflows, stream-groundwater exchange, and network geometry influence stream water composition

    NASA Astrophysics Data System (ADS)

    Mallard, John; McGlynn, Brian; Covino, Tim

    2014-06-01

    The role of stream networks and their hydrologic interaction with hillslopes and shallow groundwater in modifying and transporting watershed signals is an area of active research. One of the primary ways that stream networks can modify watershed signals is through spatially variable stream gains and losses, described herein as hydrologic turnover. We measured hydrologic gain and loss at the reach scale using tracer experiments throughout the Bull Trout watershed in the Sawtooth Mountains of Idaho. We extended the results of reach scale experiments to the stream network using empirical relationships between (1) watershed area and stream discharge and (2) stream discharge and percent stream water loss to the groundwater system. We thus incorporate linkages between (1) hillslopes and stream networks via lateral inflows and (2) stream networks and shallow groundwater via hydrologic exchange. We implemented these relationships within a concise analytical framework to simulate hydrologic turnover across stream networks and estimate the variable influence exerted by upstream reaches and streamflow source locations on stream water composition across stream networks. Application to six natural Sawtooth watersheds and seven synthetic watersheds with varying topographic structure and stream network geometry indicated that contributions to discharge from any upstream source depend on the magnitude of the initial input, but also on the distribution of hydrologic turnover occurring along the stream network. The evolution of stream water source compositions along stream networks was unique in each watershed due to the combination of watershed structure and stream network geometry. Our results suggest that a distributed representation of hydrologic turnover at the stream network scale can improve understanding of how the stream network can modify source water compositions along the stream.

  6. Algebraic Nonlinear Collective Motion

    NASA Astrophysics Data System (ADS)

    Troupe, J.; Rosensteel, G.

    1998-11-01

    Finite-dimensional Lie algebras of vector fields determine geometrical collective models in quantum and classical physics. Every set of vector fields on Euclidean space that generates the Lie algebra sl(3, R) and contains the angular momentum algebra so(3) is determined. The subset of divergence-free sl(3, R) vector fields is proven to be indexed by a real numberΛ. TheΛ=0 solution is the linear representation that corresponds to the Riemann ellipsoidal model. The nonlinear group action on Euclidean space transforms a certain family of deformed droplets among themselves. For positiveΛ, the droplets have a neck that becomes more pronounced asΛincreases; for negativeΛ, the droplets contain a spherical bubble of radius |Λ|1/3. The nonlinear vector field algebra is extended to the nonlinear general collective motion algebra gcm(3) which includes the inertia tensor. The quantum algebraic models of nonlinear nuclear collective motion are given by irreducible unitary representations of the nonlinear gcm(3) Lie algebra. These representations model fissioning isotopes (Λ>0) and bubble and two-fluid nuclei (Λ<0).

  7. Waves in Motion

    NASA Astrophysics Data System (ADS)

    McGourty, L.; Rideout, K.

    2005-12-01

    "Waves in Motion" This teaching unit was created by Leslie McGourty and Ken Rideout under the Research Experience for Teachers (RET) program at MIT Haystack Observatory during the summer of 2005. The RET program is funded by a grant from the National Science Foundation. The goals of this teaching unit are to deepen students' understanding about waves, wave motion, and the electromagnetic spectrum as a whole. Specifically students will comprehend the role radio waves play in our daily lives and in the investigation of the universe. The lessons can be used in a high school physics, earth science or astronomy curriculum. The unit consists of a series of interlocking lectures, activities, and investigations that can be used as stand alone units to supplement a teacher's existing curriculum, as an independent investigation for a student, or as a long exploration into radio astronomy with a theme of waves in space: how and where they carry their information. Special emphasis is given to the Relativity theories in honor of the "World Year of Physics" to celebrate Einstein's 1905 contributions. The lessons are currently being implemented at the high school level, the preliminary results of which will be presented. At the end of the academic year, the units will be evaluated and updated, reflecting student input and peer review after which they will be posted on the internet for teachers to use in their classrooms.

  8. Live streaming video for medical education: a laboratory model.

    PubMed

    Gandsas, Alejandro; McIntire, Katherine; Palli, Guillermo; Park, Adrian

    2002-10-01

    At the University of Kentucky (UK), we applied streaming video technology to develop a webcast model that will allow institutions to broadcast live and prerecorded surgeries, conferences, and courses in real time over networks (the Internet or an intranet). We successfully broadcast a prerecorded laparoscopic paraesophageal hernia repair to domestic and international clients by using desktop computers equipped with off-the-shelf, streaming-enabled software and standard hardware and operating systems. A web-based user interface made accessing the educational material as simple as a mouse click and allowed clients to participate in the broadcast event via an embedded e-mail/chat module. Three client computers (two connected to the Internet and a third connected to the UK intranet) requested and displayed the surgical film by means of seven common network connection configurations. Significantly, no difference in image resolution was detected with the use of a connection speed faster than 128 kilobytes per second (kbps). At this connection speed, an average bandwidth of 32.7 kbps was used, and although a 15-second delay was experienced from the time of data request to data display, the surgical film streamed continuously from beginning to end at a mean rate of 14.4 frames per second (fps). The clients easily identified all anatomic structures in full color motion, clearly followed all steps of the surgical procedure, and successfully asked questions and made comments by using the e-mail/chat module while viewing the surgery. With minimal financial investment, we have created an interactive virtual classroom with the potential to attract a global audience. Our webcast model represents a simple and practical method for institutions to supplement undergraduate and graduate surgical education and offer continuing medical education credits in a way that is convenient for clients (surgeons, students, residents, others). In the future, physicians may access streaming webcast

  9. Global perspectives on the urban stream syndrome

    USGS Publications Warehouse

    Roy, Allison; Booth, Derek B.; Capps, Krista A.; Smith, Benjamin

    2016-01-01

    Urban streams commonly express degraded physical, chemical, and biological conditions that have been collectively termed the “urban stream syndrome”. The description of the syndrome highlights the broad similarities among these streams relative to their less-impaired counterparts. Awareness of these commonalities has fostered rapid improvements in the management of urban stormwater for the protection of downstream watercourses, but the focus on the similarities among urban streams has obscured meaningful differences among them. Key drivers of stream responses to urbanization can vary greatly among climatological and physiographic regions of the globe, and the differences can be manifested in individual stream channels even through the homogenizing veneer of urban development. We provide examples of differences in natural hydrologic and geologic settings (within similar regions) that can result in different mechanisms of stream ecosystem response to urbanization and, as such, should lead to different management approaches. The idea that all urban streams can be cured using the same treatment is simplistic, but overemphasizing the tremendous differences among natural (or human-altered) systems also can paralyze management. Thoughtful integration of work that recognizes the commonalities of the urban stream syndrome across the globe has benefitted urban stream management. Now we call for a more nuanced understanding of the regional, subregional, and local attributes of any given urban stream and its watershed to advance the physical, chemical, and ecological recovery of these systems.

  10. Compressed domain moving object extraction algorithm for MPEG-2 video stream

    NASA Astrophysics Data System (ADS)

    Yang, Gaobo; Wang, Xiaojing; Zhang, Zhaoyang

    2007-11-01

    In this paper, a compressed domain moving object extraction algorithm is proposed for MPEG-2 video stream. It is mainly based on the histogram analysis of motion vectors, which can be easily obtained by partially decoding the MPEG-2 video stream. The whole algorithm framework can be divided into three key steps: motion vector pre-processing, histogram analysis of motion vector and motion vector similarity based region growing for final mask generation. A piecewise cubic hermit interpolation is utilized to form a dense motion field. The outputs of region growing algorithm based on similarity matching are the final segmentation results of moving object. These final segmentation results are further smoothed and interpolated by B-spline curve estimation. Experimental results on several test sequences demonstrate that desirable segmentation results are obtained. The accuracy of segmentation results is improved obviously, nearly to pixel level accuracy because of B-spline curve representation of segmented object. For segmentation efficiency, the processing speed is about 30ms per frame, which can meet the requirements of real time applications.

  11. Categorizing identity from facial motion.

    PubMed

    Girges, Christine; Spencer, Janine; O'Brien, Justin

    2015-01-01

    Advances in marker-less motion capture technology now allow the accurate replication of facial motion and deformation in computer-generated imagery (CGI). A forced-choice discrimination paradigm using such CGI facial animations showed that human observers can categorize identity solely from facial motion cues. Animations were generated from motion captures acquired during natural speech, thus eliciting both rigid (head rotations and translations) and nonrigid (expressional changes) motion. To limit interferences from individual differences in facial form, all animations shared the same appearance. Observers were required to discriminate between different videos of facial motion and between the facial motions of different people. Performance was compared to the control condition of orientation-inverted facial motion. The results show that observers are able to make accurate discriminations of identity in the absence of all cues except facial motion. A clear inversion effect in both tasks provided consistency with previous studies, supporting the configural view of human face perception. The accuracy of this motion capture technology thus allowed stimuli to be generated that closely resembled real moving faces. Future studies may wish to implement such methodology when studying human face perception.

  12. Stream-temperature characteristics in Georgia

    USGS Publications Warehouse

    Dyar, T.R.; Alhadeff, S. Jack

    1997-01-01

    Stream-temperature measurements for 198 periodic and 22 daily record stations were analyzed using a harmonic curve-fitting procedure. Statistics of data from 78 selected stations were used to compute a statewide stream-temperature harmonic equation, derived using latitude, drainage area, and altitude for natural streams having drainage areas greater than about 40 square miles. Based on the 1955-84 reference period, the equation may be used to compute long-term natural harmonic stream-temperature coefficients to within an on average of about 0.4? C. Basin-by-basin summaries of observed long-term stream-temperature characteristics are included for selected stations and river reaches, particularly along Georgia's mainstem streams. Changes in the stream- temperature regimen caused by the effects of development, principally impoundments and thermal power plants, are shown by comparing harmonic curves and coefficients from the estimated natural values to the observed modified-condition values.

  13. Sub-Kilometer Scale Basal Roughness of the Siple Coast Ice Streams, West Antarctic Ice Sheet

    NASA Astrophysics Data System (ADS)

    Young, D. A.; Blankenship, D. D.; Peters, M. E.

    2006-12-01

    The anastomosing series of dynamic, basally lubricated ice streams found on the Siple Coast of West Antarctica play an important role in regulating the mass balance of the West Antarctic Ice Sheet (WAIS). Geological controls on lubrication, elucidated by gravity, magnetics and seismic data, have proven important in understanding the evolution of these features. An additional indicator of basal properties, the basal roughness of ice sheets, may be an indicator of crustal geology and glacial modification, as well as a controlling parameter on ice dynamics and subglacial hydrology. For the Siple Coast ice streams, Fourier analysis of > 5 kilometer morphology (Siegert et al. 2004) revealed a correlation between ice streams and low bed roughness. Coherent high resolution data allows analysis of along track roughness at tens of meters resolution (Peters et al. 2005), however these data are limited in coverage. We extend roughness estimates into to the hundreds-of-meters length scale, using both frequency domain and autocorrelation methods, using incoherent 60 MHz radio echo sounding data collected between 1991 and 1996 on a five kilometer grid. The data cover the Bentley Subglacial Trench, Bindschadler Ice Stream, Siple Dome and the onset region of Kamb Ice Stream. SAR-processed coherent sounding data collected in 2001 are used to confirm these methods. We test for confinement of ice stream rapid basal motion to distinct morphological provinces; assess the hypothesis that marine sediments blanket much of interior of the basal WAIS; and look for correlation between ice flow and textural anisotropy.

  14. Basal characteristics of the main sticky spot in the ice plain of Whillans Ice Stream

    NASA Astrophysics Data System (ADS)

    Luthra, Tarun; Anandakrishnan, Sridhar; Alley, Richard; Winberry, Paul

    2015-04-01

    Understanding the processes that affect streaming ice flow and the mass balance of glaciers and ice sheets requires sound knowledge of the subglacial environment. Areas of high basal drag along ice streams and glaciers, termed sticky spots, are of particular interest because they inhibit the fast flow of the overriding ice and can act to redirect subglacial water flow. Whillans Ice Stream (WIS), along the Siple Coast of the West Antarctic Ice Sheet, conducts diurnal stick slip motion, largely due to a sticky spot within the main trunk of the ice stream. Previous studies have shown evidence of continuous deformable subglacial sediment presence, which is a prerequisite for fast ice stream flow. We present results from a seismic reflection experiment performed along the flow of the WIS sticky spot to image the subglacial setting related to this basal feature and elucidate its role in ice dynamics. Our results show a presence of a laterally continuous 6 m thick basal till, having P wave velocities of greater than > 1800 m/s and densities upwards of 1900 kg/m3 indicative of a stiff till suggesting the underlying bed is stronger than the overflowing ice, causing drag to the ice stream flow and possibly the main cause of the sticky spot.

  15. The influence of contrast on coherent motion processing in dyslexia.

    PubMed

    Conlon, Elizabeth G; Lilleskaret, Gry; Wright, Craig M; Power, Garry F

    2012-06-01

    The aim of the experiments was to investigate how manipulating the contrast of the signal and noise dots in a random dot kinematogram (RDK), influenced on motion coherence thresholds in adults with dyslexia. In the first of two experiments, coherent motion thresholds were measured when the contrasts of the signal and noise dots in an RDK were manipulated. A significantly greater processing benefit was found for the group with dyslexia than a control group when the signal dots were of higher contrast than the noise dots. However, a significant processing disadvantage was found for the group with dyslexia relative to the control group when the signal dots were of lower contrast than the noise dots. These findings were interpreted as supporting evidence for the noise exclusion hypothesis of dyslexia. In Experiment 2, the effect on coherent motion thresholds of presenting a cue that alerted observers to which stimuli, high or low contrast contained the signals dots was investigated. When the cue directed attention to low contrast signal dots presented in high contrast noise, coherent motion thresholds were only enhanced for the group with dyslexia. This manipulation produced equivalent coherent motion thresholds in the reader groups. In other conditions, the group with dyslexia had significantly higher coherent motion thresholds than the control group. It was concluded that adults with dyslexia who show evidence of a coherent motion deficit (37% of the dyslexia group in each experiment), have a specific difficulty in noise exclusion. This appears to occur as consequence of a sensory processing deficit in the magnocellular or dorsal stream.

  16. New motion illusion caused by pictorial motion lines.

    PubMed

    Kawabe, Takahiro; Miura, Kayo

    2008-01-01

    Motion lines (MLs) are a pictorial technique used to represent object movement in a still picture. This study explored how MLs contribute to motion perception. In Experiment 1, we reported the creation of a motion illusion caused by MLs: random displacements of objects with MLs on each frame were perceived as unidirectional global motion along the pictorial motion direction implied by MLs. In Experiment 2, we showed that the illusory global motion in the peripheral visual field captured the perceived motion direction of random displacement of objects without MLs in the central visual field, and confirmed that the results in Experiment 1 did not stem simply from response bias, but resulted from perceptual processing. In Experiment 3, we showed that the spatial arrangement of orientation information rather than ML length is important for the illusory global motion. Our results indicate that the ML effect is based on perceptual processing rather than response bias, and that comparison of neighboring orientation components may underlie the determination of pictorial motion direction with MLs.

  17. Tvashtar in Motion

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This five-frame sequence of New Horizons images captures the giant plume from Io's Tvashtar volcano. Snapped by the probe's Long Range Reconnaissance Imager (LORRI) as the spacecraft flew past Jupiter earlier this year, this first-ever 'movie' of an Io plume clearly shows motion in the cloud of volcanic debris, which extends 330 kilometers (200 miles) above the moon's surface. Only the upper part of the plume is visible from this vantage point -- the plume's source is 130 kilometers (80 miles) below the edge of Io's disk, on the far side of the moon.

    The appearance and motion of the plume is remarkably similar to an ornamental fountain on Earth, replicated on a gigantic scale. The knots and filaments that allow us to track the plume's motion are still mysterious, but this movie is likely to help scientists understand their origin, as well as provide unique information on the plume dynamics.

    Io's hyperactive nature is emphasized by the fact that two other volcanic plumes are also visible off the edge of Io's disk: Masubi at the 7 o'clock position, and a very faint plume, possibly from the volcano Zal, at the 10 o'clock position. Jupiter illuminates the night side of Io, and the most prominent feature visible on the disk is the dark horseshoe shape of the volcano Loki, likely an enormous lava lake. Boosaule Mons, which at 18 kilometers (11 miles) is the highest mountain on Io and one of the highest mountains in the solar system, pokes above the edge of the disk on the right side.

    The five images were obtained over an 8-minute span, with two minutes between frames, from 23:50 to 23:58 Universal Time on March 1, 2007. Io was 3.8 million kilometers (2.4 million miles) from New Horizons; the image is centered at Io coordinates 0 degrees north, 342 degrees west.

    The pictures were part of a sequence designed to look at Jupiter's rings, but planners included Io in the sequence because the moon was passing behind Jupiter's rings at the time.

  18. Cervical Spinal Motion During Intubation.

    DTIC Science & Technology

    2000-01-01

    Ten fresh human cadavers were intubated while recording cervical motion using a cinefluoroscopic technique. Segmental cervical motion from the...performed using no external stabilization, Gardner-Wells traction and manual in-line cervical immobilization. The data are currently being analyzed. A...paper entitled Segmental cervical spine motion during orotracheal intubation of the intact and injured spine with and without external stabilization was published in the Journal of Neurosurgery.

  19. Collective motion of dimers.

    PubMed

    Penington, Catherine J; Korvasová, Karolína; Hughes, Barry D; Landman, Kerry A

    2012-11-01

    We consider a discrete agent-based model on a one-dimensional lattice and a two-dimensional square lattice, where each agent is a dimer occupying two sites. Agents move by vacating one occupied site in favor of a nearest-neighbor site and obey either a strict simple exclusion rule or a weaker constraint that permits partial overlaps between dimers. Using indicator variables and careful probability arguments, a discrete-time master equation for these processes is derived systematically within a mean-field approximation. In the continuum limit, nonlinear diffusion equations that describe the average agent occupancy of the dimer population are obtained. In addition, we show that multiple species of interacting subpopulations give rise to advection-diffusion equations. Averaged discrete simulation data compares very well with the solution to the continuum partial differential equation models. Since many cell types are elongated rather than circular, this work offers insight into population-level behavior of collective cellular motion.

  20. ANALYSIS OF AIRCRAFT MOTIONS

    NASA Technical Reports Server (NTRS)

    Wingrove, R. C.

    1994-01-01

    This program was developed by Ames Research Center, in cooperation with the National Transportation Safety Board, as a technique for deriving time histories of an aircraft's motion from Air Traffic Control (ATC) radar records. This technique uses the radar range and azimuth data, along with the downlinked altitude data, to derive an expanded set of data which includes airspeed, lift, attitude angles (pitch, roll, and heading), etc. This technique should prove useful as a source of data in the investigation of commercial airline accidents and in the analysis of accidents involving aircraft which do not have onboard data recorders (e.g., military, short-haul, and general aviation). The technique used to determine the aircraft motions involves smoothing of raw radar data. These smoothed results, in combination with other available information (wind profiles and aircraft performance data), are used to derive the expanded set of data. This program uses a cubic least-square fit to smooth the raw data. This moving-arc procedure provides a smoothed time history of the aircraft position, the inertial velocities, and accelerations. Using known winds, these inertial data are transformed to aircraft stability axes to provide true airspeed, thrust-drag, lift, and roll angle. Further derivation, based on aircraft dependent performance data, can determine the aircraft angle of attack, pitch, and heading angle. Results of experimental tests indicate that values derived from ATC radar records using this technique agree favorably with airborne measurements. This program is written in FORTRAN IV to be executed in the batch mode, and has been implemented on a CDC 6000 series computer with a central memory requirement of 64k (octal) of 60 bit words.

  1. Relativistic Brownian motion

    NASA Astrophysics Data System (ADS)

    Dunkel, Jörn; Hänggi, Peter

    2009-02-01

    Over the past one hundred years, Brownian motion theory has contributed substantially to our understanding of various microscopic phenomena. Originally proposed as a phenomenological paradigm for atomistic matter interactions, the theory has since evolved into a broad and vivid research area, with an ever increasing number of applications in biology, chemistry, finance, and physics. The mathematical description of stochastic processes has led to new approaches in other fields, culminating in the path integral formulation of modern quantum theory. Stimulated by experimental progress in high energy physics and astrophysics, the unification of relativistic and stochastic concepts has re-attracted considerable interest during the past decade. Focusing on the framework of special relativity, we review, here, recent progress in the phenomenological description of relativistic diffusion processes. After a brief historical overview, we will summarize basic concepts from the Langevin theory of nonrelativistic Brownian motions and discuss relevant aspects of relativistic equilibrium thermostatistics. The introductory parts are followed by a detailed discussion of relativistic Langevin equations in phase space. We address the choice of time parameters, discretization rules, relativistic fluctuation-dissipation theorems, and Lorentz transformations of stochastic differential equations. The general theory is illustrated through analytical and numerical results for the diffusion of free relativistic Brownian particles. Subsequently, we discuss how Langevin-type equations can be obtained as approximations to microscopic models. The final part of the article is dedicated to relativistic diffusion processes in Minkowski spacetime. Since the velocities of relativistic particles are bounded by the speed of light, nontrivial relativistic Markov processes in spacetime do not exist; i.e., relativistic generalizations of the nonrelativistic diffusion equation and its Gaussian solutions

  2. Earthquake ground motion: Chapter 3

    USGS Publications Warehouse

    Luco, Nicolas; Valley, Michael; Crouse, C.B.

    2012-01-01

    Most of the effort in seismic design of buildings and other structures is focused on structural design. This chapter addresses another key aspect of the design process—characterization of earthquake ground motion. Section 3.1 describes the basis of the earthquake ground motion maps in the Provisions and in ASCE 7. Section 3.2 has examples for the determination of ground motion parameters and spectra for use in design. Section 3.3 discusses and provides an example for the selection and scaling of ground motion records for use in response history analysis.

  3. Diagnostic of plasma streams from ion thrusters for space propulsion using emissive probes

    NASA Astrophysics Data System (ADS)

    Conde, L.; Tierno, S. P.; Domenech-Garret, J. L.; Donoso, J. M.; Castillo, M. A.; Eíriz, I.; Sáez de Ocáriz, I.

    2016-10-01

    The emissive probes are employed for the determination of the local plasma potential of plasma streams produced by ion thrusters. Its operation basically relies on electron collection and emission and are less sensitive to the ion motion than collecting probes. The diagnostic using emissive probes is reviewed with emphasis in low density plasmas. Our results support the conclusion that potential structures around the probe, as virtual cathodes, would be responsible for the operation of emissive probes in low density plasmas.

  4. Assessing stream temperature response to environmental change

    NASA Astrophysics Data System (ADS)

    MacDonald, R. J.; Boon, S.; Byrne, J. M.

    2010-12-01

    Stream temperature controls aquatic ecosystem function by directly influencing water quality, ecosystem productivity, and the physiological functioning of aquatic organisms. To date, there are limited studies of the impacts of environmental disturbance on stream temperature, particularly on the eastern slopes of the Rocky Mountains. This region provides key habitat for native salmonid species such as westslope cutthroat trout (Oncorhynchus clarkii lewisi) and bull trout (Salvelinus confluentus), which are listed as ‘threatened’ and ‘species of special concern’, respectively. Increases in stream temperature could limit habitat availability, reduce competitive advantage, and potentially increase mortality rates for these native species. This study uses field data collected at high spatiotemporal resolution to develop a spatial stream temperature model that simulates the mass and energy balance of the stream system. Preliminary field results demonstrate the high spatial and temporal variability in processes governing stream temperature in three study stream reaches. Groundwater/surface water interactions, topographic setting, and local meteorological conditions all contribute in determining stream thermal regimes. This work discusses how these primary drivers of stream temperature can be incorporated into a physically based spatial model, and demonstrates how depending on the scale of interest, the temperature of a stream can be governed by very different contributing factors.

  5. Ice-Shelf Flexure and Tidal Forcing of Bindschadler Ice Stream, West Antarctica

    NASA Technical Reports Server (NTRS)

    Walker, Ryan T.; Parizek, Bryron R.; Alley, Richard B.; Brunt, Kelly M.; Anandakrishnan, Sridhar

    2014-01-01

    Viscoelastic models of ice-shelf flexure and ice-stream velocity perturbations are combined into a single efficient flowline model to study tidal forcing of grounded ice. The magnitude and timing of icestream response to tidally driven changes in hydrostatic pressure and/or basal drag are found to depend significantly on bed rheology, with only a perfectly plastic bed allowing instantaneous velocity response at the grounding line. The model can reasonably reproduce GPS observations near the grounding zone of Bindschadler Ice Stream (formerly Ice Stream D) on semidiurnal time scales; however, other forcings such as tidally driven ice-shelf slope transverse to the flowline and flexurally driven till deformation must also be considered if diurnal motion is to be matched

  6. Free stream capturing in fluid conservation law for moving coordinates in three dimensions

    NASA Technical Reports Server (NTRS)

    Obayashi, Shigeru

    1991-01-01

    The free-stream capturing technique for both the finite-volume (FV) and finite-difference (FD) framework is summarized. For an arbitrary motion of the grid, the FV analysis shows that volumes swept by all six surfaces of the cell have to be computed correctly. This means that the free-stream capturing time-metric terms should be calculated not only from a surface vector of a cell at a single time level, but also from a volume swept by the cell surface in space and time. The FV free-stream capturing formulation is applicable to the FD formulation by proper translation from an FV cell to an FD mesh.

  7. A Disynaptic Relay from Superior Colliculus to Dorsal Stream Visual Cortex in Macaque Monkey

    PubMed Central

    Lyon, David C.; Nassi, Jonathan J.; Callaway, Edward M.

    2010-01-01

    The superior colliculus (SC) is the first station in a subcortical relay of retinal information to extrastriate visual cortex. Ascending SC projections pass through pulvinar and LGN on their way to cortex, but it is not clear how many synapses are required to complete these circuits or which cortical areas are involved. To examine this relay directly, we injected transynaptic rabies virus into several extrastriate visual areas. We observed disynaptically labeled cells in superficial, retino-recipient SC layers from injections in dorsal stream areas MT and V3, but not the earliest extrastriate area, V2, nor ventral stream area V4. This robust SC-dorsal stream pathway is most likely relayed through the inferior pulvinar and can provide magnocellular-like sensory inputs necessary for motion perception and the computation of orienting movements. Furthermore, by circumventing primary visual cortex, this pathway may also underlie the remaining visual capacities associated with blindsight. PMID:20152132

  8. Simulation Data as Data Streams

    SciTech Connect

    Abdulla, G; Arrighi, W; Critchlow, T

    2003-11-18

    Computational or scientific simulations are increasingly being applied to solve a variety of scientific problems. Domains such as astrophysics, engineering, chemistry, biology, and environmental studies are benefiting from this important capability. Simulations, however, produce enormous amounts of data that need to be analyzed and understood. In this overview paper, we describe scientific simulation data, its characteristics, and the way scientists generate and use the data. We then compare and contrast simulation data to data streams. Finally, we describe our approach to analyzing simulation data, present the AQSim (Ad-hoc Queries for Simulation data) system, and discuss some of the challenges that result from handling this kind of data.

  9. Quantifying and controlling collective motion in externally guided cells

    NASA Astrophysics Data System (ADS)

    Parker, Joshua; Guven, Can; Wang, Chenlu; Ott, Edward; Losert, Wolfgang

    2015-03-01

    Many motile cells use chemical signals to coordinate their motion to aid in performing a larger task, be it healing a wound or aggregating to form a spore. This coordination can vary from subtle variations in overall alignment to broad, visibly structured patterns. Of particular interest of study are two organisms We introduce a model for motion towards a chemical signal and study these spatio-temporal correlations in the context of autocrine relay, such as seen in Dictyostelium discoideum, where we demonstrate that adhesion and chemical degradation both enhance visible ``streaming'' structures. We also study a model of paracrine signal relay relevant to human neutrophil migration and demonstrate how temporally varying chemical signals can be used to coordinate cell migration. We discuss both of these results in the context of their relevance to the survival of the organism and highlight future experimental tests.

  10. Earthquake detection by new motion estimation algorithm in video processing

    NASA Astrophysics Data System (ADS)

    Hong, Chien-Shiang; Wang, Chuen-Ching; Tai, Shen-Chuan; Chen, Ji-Feng; Wang, Chung-Yao

    2011-01-01

    As increasing urbanization is taking place worldwide, earthquake hazards pose serious threats to lives and properties for urban areas. A practical earthquake prediction method appears to be far from realization. Generally, the traditional instruments for earthquake detection have the disadvantages of high cost and size. To solve these problems, this paper presents a new method which can detect earthquake intensity using video capture device. The main method is based on a new proposed motion vector algorithm with simple but effective methods to immediately calculate acceleration of a predefined target object. By estimating the motion vector variation, the movement distance of predefined target object can be computed, and therefore the earthquake amplitude can be defined. The effectiveness of the proposed scheme is demonstrated in a series of experimental simulations. It is shown that the scheme successfully detects the earthquake occurrence and identifies the earthquake amplitude from video streams.

  11. Cash streams: five powerful income streams to increase your net income.

    PubMed

    Means, G B

    1998-01-01

    You can dramatically increase your profits by: Cash stream #1--extending credit and earning interest on the unpaid balance; Cash stream #2--doing all of the undone treatment in your practice; Cash stream #3--providing financing for everyone who deserves it; Cash stream #4--treating bigger cases; Cash stream #5--avoid treating deadbeats. There isn't anything I know of, which will jump start your practice as much as these five cash streams--more new patients, better case acceptance as well as increased cash flow. But you must get good at financing. You must have in place an organized, proven, financing system--just like the finance companies do.

  12. Motion-Matching: A Challenge Game to Generate Motion Concepts

    NASA Astrophysics Data System (ADS)

    Schuster, David; Adams, Betty; Brookes, David; Milner-Bolotin, Marina; Undreiu, Adriana

    2009-10-01

    Motion is a topic that is taught from elementary grades through to university at various levels of sophistication. It is an area that can be challenging for learning in a conceptually meaningful way, and formal kinematics instruction can sometimes seem dry and boring. Thus, the nature of students' initial introduction to motion is important in sparking their interest, shaping their perspective, and developing conceptual understanding of motion. The kinematic concepts we want students to acquire for basic motions are: position, time, speed, direction, velocity, velocity change, change rate, and acceleration, all with respect to a frame of reference. In this article we describe a challenge game used as an "opener" to motion, in which students themselves essentially generate these concepts, in everyday language, from a perceived need for them.

  13. Motion Predicts Clinical Callus Formation

    PubMed Central

    Elkins, Jacob; Marsh, J. Lawrence; Lujan, Trevor; Peindl, Richard; Kellam, James; Anderson, Donald D.; Lack, William

    2016-01-01

    Background: Mechanotransduction is theorized to influence fracture-healing, but optimal fracture-site motion is poorly defined. We hypothesized that three-dimensional (3-D) fracture-site motion as estimated by finite element (FE) analysis would influence callus formation for a clinical series of supracondylar femoral fractures treated with locking-plate fixation. Methods: Construct-specific FE modeling simulated 3-D fracture-site motion for sixty-six supracondylar femoral fractures (OTA/AO classification of 33A or 33C) treated at a single institution. Construct stiffness and directional motion through the fracture were investigated to assess the validity of construct stiffness as a surrogate measure of 3-D motion at the fracture site. Callus formation was assessed radiographically for all patients at six, twelve, and twenty-four weeks postoperatively. Univariate and multivariate linear regression analyses examined the effects of longitudinal motion, shear (transverse motion), open fracture, smoking, and diabetes on callus formation. Construct types were compared to determine whether their 3-D motion profile was associated with callus formation. Results: Shear disproportionately increased relative to longitudinal motion with increasing bridge span, which was not predicted by our assessment of construct stiffness alone. Callus formation was not associated with open fracture, smoking, or diabetes at six, twelve, or twenty-four weeks. However, callus formation was associated with 3-D fracture-site motion at twelve and twenty-four weeks. Longitudinal motion promoted callus formation at twelve and twenty-four weeks (p = 0.017 for both). Shear inhibited callus formation at twelve and twenty-four weeks (p = 0.017 and p = 0.022, respectively). Titanium constructs with a short bridge span demonstrated greater longitudinal motion with less shear than did the other constructs, and this was associated with greater callus formation (p < 0.001). Conclusions: In this study of

  14. Probing the time course of head-motion cues integration during auditory scene analysis.

    PubMed

    Kondo, Hirohito M; Toshima, Iwaki; Pressnitzer, Daniel; Kashino, Makio

    2014-01-01

    The perceptual organization of auditory scenes is a hard but important problem to solve for human listeners. It is thus likely that cues from several modalities are pooled for auditory scene analysis, including sensory-motor cues related to the active exploration of the scene. We previously reported a strong effect of head motion on auditory streaming. Streaming refers to an experimental paradigm where listeners hear sequences of pure tones, and rate their perception of one or more subjective sources called streams. To disentangle the effects of head motion (changes in acoustic cues at the ear, subjective location cues, and motor cues), we used a robotic telepresence system, Telehead. We found that head motion induced perceptual reorganization even when the acoustic scene had not changed. Here we reanalyzed the same data to probe the time course of sensory-motor integration. We show that motor cues had a different time course compared to acoustic or subjective location cues: motor cues impacted perceptual organization earlier and for a shorter time than other cues, with successive positive and negative contributions to streaming. An additional experiment controlled for the effects of volitional anticipatory components, and found that arm or leg movements did not have any impact on scene analysis. These data provide a first investigation of the time course of the complex integration of sensory-motor cues in an auditory scene analysis task, and they suggest a loose temporal coupling between the different mechanisms involved.

  15. Sentiment Knowledge Discovery in Twitter Streaming Data

    NASA Astrophysics Data System (ADS)

    Bifet, Albert; Frank, Eibe

    Micro-blogs are a challenging new source of information for data mining techniques. Twitter is a micro-blogging service built to discover what is happening at any moment in time, anywhere in the world. Twitter messages are short, and generated constantly, and well suited for knowledge discovery using data stream mining. We briefly discuss the challenges that Twitter data streams pose, focusing on classification problems, and then consider these streams for opinion mining and sentiment analysis. To deal with streaming unbalanced classes, we propose a sliding window Kappa statistic for evaluation in time-changing data streams. Using this statistic we perform a study on Twitter data using learning algorithms for data streams.

  16. Transitive closure on the imagine stream processor

    SciTech Connect

    Griem, Gorden; Oliker, Leonid

    2003-11-11

    The increasing gap between processor and memory speeds is a well-known problem in modern computer architecture. The Imagine system is designed to address the processor-memory gap through streaming technology. Stream processors are best-suited for computationally intensive applications characterized by high data parallelism and producer-consumer locality with minimal data dependencies. This work examines an efficient streaming implementation of the computationally intensive Transitive Closure (TC) algorithm on the Imagine platform. We develop a tiled TC algorithm specifically for the Imagine environment, which efficiently reuses streams to minimize expensive off-chip data transfers. The implementation requires complex stream programming since the memory hierarchy and cluster organization of the underlying architecture are exposed to the Imagine programmer. Results demonstrate that limited performance of TC is achieved primarily due to the complicated data-dependencies of the blocked algorithm. This work is an ongoing effort to identify classes of scientific problems well-suited for streaming processors.

  17. Streaming potential measurements of biosurfaces

    NASA Technical Reports Server (NTRS)

    Van Wagenen, R. A.; Andrade, J. D.; Hibbs, J. B., Jr.

    1976-01-01

    A technique based on the measurement of streaming potentials has been developed to evaluate the electrokinetic region of the cell periphery. This approach is feasible for cell lines propagated in in-vitro cell cultures in monolayer form. The advantage of this system is that cells may be evaluated in the living state atttached to a substrate; it is not necessary to subject the cells to enzymatic, chemical, or mechanical trauma required to obtain monodisperse suspensions which are then normally evaluated by microelectrophoresis. In this manner, it should be possible to study the influence of substrate and environmental factors on the charge density and potential at the cell periphery. The apparatus and procedure are described as well as some results concerning the electrokinetic potential of borosilicate capillaries as a function of ionic strength, pH, and temperature. The effect that turbulence and entrance flow conditions have on accurate streaming-potential measurements is discussed. The electrokinetic potential of BALB/c 3T12 fibroblasts has been quantified as a function of pH, ionic strength, glutaraldehyde fixation, and Giemsa staining.

  18. Topographic Structure from Motion

    NASA Astrophysics Data System (ADS)

    Fonstad, M. A.; Dietrich, J. T.; Courville, B. C.; Jensen, J.; Carbonneau, P.

    2011-12-01

    The production of high-resolution topographic datasets is of increasing concern and application throughout the geomorphic sciences, and river science is no exception. Consequently, a wide range of topographic measurement methods have evolved. Despite the range of available methods, the production of high resolution, high quality digital elevation models (DEMs) generally requires a significant investment in personnel time, hardware and/or software. However, image-based methods such as digital photogrammetry have steadily been decreasing in costs. Initially developed for the purpose of rapid, inexpensive and easy three dimensional surveys of buildings or small objects, the "structure from motion" photogrammetric approach (SfM) is a purely image based method which could deliver a step-change if transferred to river remote sensing, and requires very little training and is extremely inexpensive. Using the online SfM program Microsoft Photosynth, we have created high-resolution digital elevation models (DEM) of rivers from ordinary photographs produced from a multi-step workflow that takes advantage of free and open source software. This process reconstructs real world scenes from SfM algorithms based on the derived positions of the photographs in three-dimensional space. One of the products of the SfM process is a three-dimensional point cloud of features present in the input photographs. This point cloud can be georeferenced from a small number of ground control points collected via GPS in the field. The georeferenced point cloud can then be used to create a variety of digital elevation model products. Among several study sites, we examine the applicability of SfM in the Pedernales River in Texas (USA), where several hundred images taken from a hand-held helikite are used to produce DEMs of the fluvial topographic environment. This test shows that SfM and low-altitude platforms can produce point clouds with point densities considerably better than airborne LiDAR, with

  19. Network Characteristics of Video Streaming Traffic

    DTIC Science & Technology

    2011-11-01

    character- istics of this traffic. In this paper, we study the network char- acteristics of the two most popular video streaming services, Netflix and... Netflix and YouTube [9]. YouTube is also the most popular source of video streaming traffic in Europe and Latin America [9, 22]. Despite this...popularity, little is known about the strategies used by YouTube and Netflix to stream their videos. These strategies might have a fundamental im- pact on

  20. The Man Who Mastered Motion.

    ERIC Educational Resources Information Center

    Radetsky, Peter

    1986-01-01

    Explains the principles of the science of motion and examines Thomas Kane's deductive approach to the study of dynamics. Also recounts Kane's advances in explaining classic mechanics and discusses the advantages of his methods in the formulation of equations of motion and in applications to space technology. (ML)

  1. Statistical description of tectonic motions

    NASA Technical Reports Server (NTRS)

    Agnew, Duncan Carr

    1993-01-01

    This report summarizes investigations regarding tectonic motions. The topics discussed include statistics of crustal deformation, Earth rotation studies, using multitaper spectrum analysis techniques applied to both space-geodetic data and conventional astrometric estimates of the Earth's polar motion, and the development, design, and installation of high-stability geodetic monuments for use with the global positioning system.

  2. An open architecture motion controller

    NASA Technical Reports Server (NTRS)

    Rossol, Lothar

    1994-01-01

    Nomad, an open architecture motion controller, is described. It is formed by a combination of TMOS, C-WORKS, and other utilities. Nomad software runs in a UNIX environment and provides for sensor-controlled robotic motions, with user replaceable kinematics. It can also be tailored for highly specialized applications. Open controllers such as Nomad should have a major impact on the robotics industry.

  3. Fast motion prediction algorithm for multiview video coding

    NASA Astrophysics Data System (ADS)

    Abdelazim, Abdelrahman; Zhang, Guang Y.; Mein, Stephen J.; Varley, Martin R.; Ait-Boudaoud, Djamel

    2011-06-01

    Multiview Video Coding (MVC) is an extension to the H.264/MPEG-4 AVC video compression standard developed with joint efforts by MPEG/VCEG to enable efficient encoding of sequences captured simultaneously from multiple cameras using a single video stream. Therefore the design is aimed at exploiting inter-view dependencies in addition to reducing temporal redundancies. However, this further increases the overall encoding complexity In this paper, the high correlation between a macroblock and its enclosed partitions is utilised to estimate motion homogeneity, and based on the result inter-view prediction is selectively enabled or disabled. Moreover, if the MVC is divided into three layers in terms of motion prediction; the first being the full and sub-pixel motion search, the second being the mode selection process and the third being repetition of the first and second for inter-view prediction, the proposed algorithm significantly reduces the complexity in the three layers. To assess the proposed algorithm, a comprehensive set of experiments were conducted. The results show that the proposed algorithm significantly reduces the motion estimation time whilst maintaining similar Rate Distortion performance, when compared to both the H.264/MVC reference software and recently reported work.

  4. Depletion force induced collective motion of microtubules driven by kinesin.

    PubMed

    Inoue, Daisuke; Mahmot, Bulbul; Kabir, Arif Md Rashedul; Farhana, Tamanna Ishrat; Tokuraku, Kiyotaka; Sada, Kazuki; Konagaya, Akihiko; Kakugo, Akira

    2015-11-21

    Collective motion is a fascinating example of coordinated behavior of self-propelled objects, which is often associated with the formation of large scale patterns. Nowadays, the in vitro gliding assay is being considered a model system to experimentally investigate various aspects of group behavior and pattern formation by self-propelled objects. In the in vitro gliding assay, cytoskeletal filaments F-actin or microtubules are driven by the surface immobilized associated biomolecular motors myosin or dynein respectively. Although the F-actin/myosin or microtubule/dynein system was found to be promising in understanding the collective motion and pattern formation by self-propelled objects, the most widely used biomolecular motor system microtubule/kinesin could not be successfully employed so far in this regard. Failure in exhibiting collective motion by kinesin driven microtubules is attributed to the intrinsic properties of kinesin, which was speculated to affect the behavior of individual gliding microtubules and mutual interactions among them. In this work, for the first time, we have demonstrated the collective motion of kinesin driven microtubules by regulating the mutual interaction among the gliding microtubules, by employing a depletion force among them. Proper regulation of the mutual interaction among the gliding microtubules through the employment of the depletion force was found to allow the exhibition of collective motion and stream pattern formation by the microtubules. This work offers a universal means for demonstrating the collective motion using the in vitro gliding assay of biomolecular motor systems and will help obtain a meticulous understanding of the fascinating coordinated behavior and pattern formation by self-propelled objects.

  5. The Equations of Oceanic Motions

    NASA Astrophysics Data System (ADS)

    Müller, Peter

    2006-10-01

    Modeling and prediction of oceanographic phenomena and climate is based on the integration of dynamic equations. The Equations of Oceanic Motions derives and systematically classifies the most common dynamic equations used in physical oceanography, from large scale thermohaline circulations to those governing small scale motions and turbulence. After establishing the basic dynamical equations that describe all oceanic motions, M|ller then derives approximate equations, emphasizing the assumptions made and physical processes eliminated. He distinguishes between geometric, thermodynamic and dynamic approximations and between the acoustic, gravity, vortical and temperature-salinity modes of motion. Basic concepts and formulae of equilibrium thermodynamics, vector and tensor calculus, curvilinear coordinate systems, and the kinematics of fluid motion and wave propagation are covered in appendices. Providing the basic theoretical background for graduate students and researchers of physical oceanography and climate science, this book will serve as both a comprehensive text and an essential reference.

  6. Crowding of biological motion stimuli.

    PubMed

    Ikeda, Hanako; Watanabe, Katsumi; Cavanagh, Patrick

    2013-03-26

    It is difficult to identify a target in the peripheral visual field when it is flanked by distractors. In the present study, we investigated this "crowding" effect for biological motion stimuli. Three walking biological motion stimuli were presented horizontally in the periphery with various distances between them, and observers reported the walking direction of the central figure. When the inter-walker distance was small, discriminating the direction became difficult. Moreover, the reported direction for the central target was not simply noisier, but reflected a degree of pooling of the three directions from the target and two flankers. However, when the two flanking distractors were scrambled walking biological motion stimuli, crowding was not seen. This result suggests that the crowding of biological motion stimuli occurs at a high-level of motion perception.

  7. The Perception of Auditory Motion

    PubMed Central

    Leung, Johahn

    2016-01-01

    The growing availability of efficient and relatively inexpensive virtual auditory display technology has provided new research platforms to explore the perception of auditory motion. At the same time, deployment of these technologies in command and control as well as in entertainment roles is generating an increasing need to better understand the complex processes underlying auditory motion perception. This is a particularly challenging processing feat because it involves the rapid deconvolution of the relative change in the locations of sound sources produced by rotational and translations of the head in space (self-motion) to enable the perception of actual source motion. The fact that we perceive our auditory world to be stable despite almost continual movement of the head demonstrates the efficiency and effectiveness of this process. This review examines the acoustical basis of auditory motion perception and a wide range of psychophysical, electrophysiological, and cortical imaging studies that have probed the limits and possible mechanisms underlying this perception. PMID:27094029

  8. Natural Stream Channel Design Techniques and Review

    EPA Pesticide Factsheets

    Need for a Review Checklist: Stream restoration problems include; design complexity, many different design methodologies, inconsistency in design deliverables, communication difficulties, many failed projects

  9. Motion words selectively modulate direction discrimination sensitivity for threshold motion

    PubMed Central

    Pavan, Andrea; Skujevskis, Māris; Baggio, Giosuè

    2013-01-01

    Can speech selectively modulate the sensitivity of a sensory system so that, in the presence of a suitable linguistic context, the discrimination of certain perceptual features becomes more or less likely? In this study, participants heard upward or downward motion words followed by a single visual field of random dots moving upwards or downwards. The time interval between the onsets of the auditory and the visual stimuli was varied parametrically. Motion direction could be either discriminable (suprathreshold motion) or non-discriminable (threshold motion). Participants had to judge whether the dots were moving upward or downward. Results show a double dissociation between discrimination sensitivity (d′) and reaction times depending on whether vertical motion was above or at threshold. With suprathreshold motion, responses were faster for congruent directions of words and dots, but sensitivity was equal across conditions. With threshold motion, sensitivity was higher for congruent directions of words and dots, but responses were equally fast across conditions. The observed differences in sensitivity and response times were largest when the dots appeared 450 ms after word onset, that is, consistently with electrophysiology, at the time the up/down semantics of the word had become available. These data suggest that word meanings can alter the balance between signal and noise within the visual system and affect the perception of low-level sensory features. PMID:23596407

  10. Assessment of Tidal Stream Energy Potential for the United States

    NASA Astrophysics Data System (ADS)

    Haas, K. A.; Defne, Z.; Jiang, L.; Fritz, H. M.

    2010-12-01

    Tidal streams are high velocity sea currents created by periodic horizontal movement of the tides, often magnified by local topographical features such as headlands, inlets to inland lagoons, and straits. Tidal stream energy extraction is derived from the kinetic energy of the moving flow; analogous to the way a wind turbine operates in air, and as such differs from tidal barrages, which relies on providing a head of water for energy extraction. With the constantly increasing effort in promoting alternative energy, tidal streams have become promising energy sources due to their continuous, predictable and concentrated characteristics. However, the present lack of a full spatial-temporal assessment of tidal currents for the U.S. coastline down to the scale of individual devices is a barrier to the comprehensive development of tidal current energy technology. A methodology for creating a national database of tidal stream energy potential, as well as a GIS tool usable by industry in order to accelerate the market for tidal energy conversion technology has been developed. The tidal flows are simulated using the Regional Ocean Modeling System (ROMS). The model is calibrated and validated using observations and tidal predictions. The calibration includes adjustments to model parameters such as bottom friction coefficient, changed land/water masks, or increased grid resolutions. A systematic validation process has been developed after defining various parameters to quantify the validation results. In order to determine the total tidal stream power resource, a common method frequently proposed is to estimate it as a fraction of the total kinetic energy flux passing through a vertical section; however, this now has been shown to generally underestimate the total available resource. The total tidal energy flux includes not just the kinetic energy but also the energy flux due to the work done by the pressure force associated with the tidal motion on the water column as well

  11. THERMAL HETEROGENEITY, STREAM CHANNEL MORPHOLOGY, AND SALMONID ABUNDANCE IN NORTHEASTERN OREGON STREAMS

    EPA Science Inventory

    Heterogeneity in stream water temperatures created by local influx of cooler subsurface waters into geomorphically complex stream channels was associated with increased abundance of rainbow trout (Oncorhynchus mykiss) and chinook salmon (O. tshawytscha) in northeastern Oregon. Th...

  12. Ghost removing for HDR real-time video stream generation

    NASA Astrophysics Data System (ADS)

    Bouderbane, Mustapha; Dubois, Julien; Heyrman, Barthélémy; Lapray, Pierre-Jean; Ginhac, Dominique

    2016-04-01

    High dynamic range (HDR) imaging generation from a set of low dynamic range images taken in different exposure times is a low cost and an easy technique. This technique provides a good result for static scenes. Temporal exposure bracketing cannot be applied directly for dynamic scenes, since camera or object motion in bracketed exposures creates ghosts in the resulting HDR image. In this paper we describe a real-time ghost removing hardware implementation on high dynamic range video ow added for our HDR FPGA based smart camera which is able to provide full resolution (1280 x 1024) HDR video stream at 60 fps. We present experimental results to show the efficiency of our implemented method in ghost removing.

  13. Towards social interaction detection in egocentric photo-streams

    NASA Astrophysics Data System (ADS)

    Aghaei, Maedeh; Dimiccoli, Mariella; Radeva, Petia

    2015-12-01

    Detecting social interaction in videos relying solely on visual cues is a valuable task that is receiving increasing attention in recent years. In this work, we address this problem in the challenging domain of egocentric photo-streams captured by a low temporal resolution wearable camera (2fpm). The major difficulties to be handled in this context are the sparsity of observations as well as unpredictability of camera motion and attention orientation due to the fact that the camera is worn as part of clothing. Our method consists of four steps: multi-faces localization and tracking, 3D localization, pose estimation and analysis of f-formations. By estimating pair-to-pair interaction probabilities over the sequence, our method states the presence or absence of interaction with the camera wearer and specifies which people are more involved in the interaction. We tested our method over a dataset of 18.000 images and we show its reliability on our considered purpose.

  14. OB stars in the Leading Arm of the Magellanic Stream

    NASA Astrophysics Data System (ADS)

    Moni Bidin, C.; Casetti-Dinescu, D. I.; Méndez, R. A.; Girard, T. M.; Vieira, K.; Korchagin, V. I.; van Altena, W. F.

    2015-05-01

    We present our spectroscopic program aimed to study some new interesting features recently discovered in the Magellanic Cloud System. These were revealed by the spatial distribution of OB-type candidate stars selected based on UV, optical, and IR photometry and proper motions from existing large-area catalogs. As a pilot study of our project, we are studying OB-star candidates in the Leading Arm (LA) of the Magellanic Stream, a gaseous tidal structure with no stellar counterpart known so far. Our targets group in three clumps near regions of high HI density in the LA. If confirmed, these young stars would evidence recent star formation in the LA, and they would help better understand and constrain the formation of the LA and its interactions with the Milky Way.

  15. Collaborating with beaver: An affordable, process-based approach to stream restoration

    NASA Astrophysics Data System (ADS)

    Pollock, M. M.; Jordan, C.; Bouwes, N. W.; Volk, C.; Tattam, I.

    2009-12-01

    We review the initial results of a long-term restoration and monitoring project to restore the lower 32 km of Bridge Creek, an incised and degraded tributary to the John Day River in eastern Oregon, USA. The goal of the project is to cause a detectable population-level benefit to the anadromous steelhead trout (Oncorhynchus mykiss) that use this system. The project takes a process-based restoration approach that involves installing a series of beaver dam support structures designed to mimic beaver dams and to assist beaver (Castor canadensis) in the construction of stable dams. Currently beaver are active in the system, but the lack of structure in the incised stream trench prevents them from establishing dams that last more than one or two years. The lack of stream sinuosity and lack of access to a floodplain concentrates flow forces within the confined incision trench and the dams are regularly breached during high flows in spring or summer. A major goal of this project is to have the beaver do the bulk of the restoration work while we facilitate establishing stable beaver colonies in this degraded stream system such that the small population can expand. As such, the project is not an “engineered” approach to stream restoration with a spatially fixed outcome. Providing some short term assistance to set in motion natural processes by which the stream restores its natural dynamics is the expected outcome. Initial results suggest that increasing the number of beaver dams facilitate stream geomorphic changes that include sediment retention, stream bed aggradation, increased stream sinuosity, pool formation, increased stream length, reduced stream slope, reduced bed shear stress and a shift in the bed composition from cobble towards gravel. The beaver dams also raise water tables in the alluvial aquifer, expand the riparian forest and reduce stream temperatures. Beaver Dam Support Structure colonized by beaver shortly after installation. A plunge pool has formed

  16. Interaction between stream temperature, streamflow, and groundwater exchanges in alpine streams

    USGS Publications Warehouse

    Constantz, J.

    1998-01-01

    Four alpine streams were monitored to continuously collect stream temperature and streamflow for periods ranging from a week to a year. In a small stream in the Colorado Rockies, diurnal variations in both stream temperature and streamflow were significantly greater in losing reaches than in gaining reaches, with minimum streamflow losses occurring early in the day and maximum losses occurring early in the evening. Using measured stream temperature changes, diurnal streambed infiltration rates were predicted to increase as much as 35% during the day (based on a heat and water transport groundwater model), while the measured increase in streamflow loss was 40%. For two large streams in the Sierra Nevada Mountains, annual stream temperature variations ranged from 0??to 25??C. In summer months, diurnal stream temperature variations were 30-40% of annual stream temperature variations, owing to reduced streamflows and increased atmospheric heating. Previous reports document that one Sierra stream site generally gains groundwater during low flows, while the second Sierra stream site may lose water during low flows. For August the diurnal streamflow variation was 11% at the gaining stream site and 30% at the losing stream site. On the basis of measured diurnal stream temperature variations, streambed infiltration rates were predicted to vary diurnally as much as 20% at the losing stream site. Analysis of results suggests that evapotranspiration losses determined diurnal streamflow variations in the gaining reaches, while in the losing reaches, evapotranspiration losses were compounded by diurnal variations in streambed infiltration. Diurnal variations in stream temperature were reduced in the gaining reaches as a result of discharging groundwater of relatively constant temperature. For the Sierra sites, comparison of results with those from a small tributary demonstrated that stream temperature patterns were useful in delineating discharges of bank storage following dam

  17. Polarimetry of motional Stark effect and determination of current profiles in DIII-D

    SciTech Connect

    Wroblewski, D. ); Lao, L.L. )

    1992-05-01

    The motional electric field E = v {times} B, where v is the velocity and B is the tokamak magnetic field, produces a strong Stark effect in spectral lines emitted by hydrogenic neutral beams. The tilt angle of the magnetic field line, a quantity related directly to the distribution of the plasma toroidal current, is deduced from a measurement of the direction of polarization of the Stark components. In the DIII-D tokamak, the Balmer-{alpha} line of deuterium emitted by one of the high-power heating beams is analyzed. A multichord polarimeter measures the magnetic field pitch angle at eight spatial locations covering {approximately}0.6 of the nominal plasma diameter at the midplane outboard side. The diagnostic offers 2 to 8 cm resolution in the major radius and 1 ms integration time. The accuracy of the measurement of the polarization direction necessary for an adequate reconstruction of the current profiles is obtained with the use of active polarizing elements which produce high frequency intensity modulation with an amplitude related to the direction of linear polarization of the plasma radiation. The current profiles in highly shaped (non-circular) plasmas cannot be determined solely from the tilt angle measurements because they do not provide any information about the shape of magnetic surfaces. Thus, the polarization measurement are used in conjunction with a large set of external magnetic measurements (magnetic field and flux probes, diamagnetic loops, and Rogowski coils) by the magnetic field equilibrium code EFIT, and provide a constraint on the possible solutions for the current profile.

  18. Storage requirements for Georgia streams

    USGS Publications Warehouse

    Carter, Robert F.

    1983-01-01

    The suitability of a stream as a source of water supply or for waste disposal may be severely limited by low flow during certain periods. A water user may be forced to provide storage facilities to supplement the natural flow if the low flow is insufficient for his needs. This report provides data for evaluating the feasibility of augmenting low streamflow by means of storage facilities. It contains tabular data on storage requirements for draft rates that are as much as 60 percent of the mean annual flow at 99 continuous-record gaging stations, and draft-storage diagrams for estimating storage requirements at many additional sites. Through analyses of streamflow data, the State was divided into four regions. Draft-storage diagrams for each region provide a means of estimating storage requirements for sites on streams where data are scant, provided the drainage area, mean annual flow, and the 7-day, 10-year low flow are known or can be estimated. These data are tabulated for the 99 gaging stations used in the analyses and for 102 partial-record sites where only base-flow measurements have been made. The draft-storage diagrams are useful not only for estimating in-channel storage required for low-flow augmentation, but also can be used for estimating the volume of off-channel storage required to retain wastewater during low-flow periods for later release. In addition, these relationships can be helpful in estimating the volume of wastewater to be disposed of by spraying on land, provided that the water disposed of in this manner is only that for which streamflow dilution water is not currently available. Mean annual flow can be determined for any stream within the State by using the runoff map in this report. Low-flow indices can be estimated by several methods, including correlation of base-flow measurements with concurrent flow at nearby continuous-record gaging stations where low-flow indices have been determined.

  19. 5 CFR 1201.55 - Motions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... for extension of time, a motion for postponement of a hearing, or any other procedural motion must first contact the other party to determine whether there is any objection to the motion, and must state... motion. Judges, in their discretion, may grant or deny motions for extensions of time to file...

  20. Scaling relationship between rotation and translation motions

    NASA Astrophysics Data System (ADS)

    Chiu, Hung-Chie

    2016-04-01

    Rotation motion and its effects are not well known and our knowledge about translation motions is much better than that of the rotation motions. Since rotation motions show to have a close relationship with translation motions, deriving such relationship might improve our understanding on rotation motions. Rotation motion can be obtained by taking a spatial derivative of translation motion. Therefore, rotation motion is always accompanied by translation motions. Although rotation motion cannot be detected by strong motion record, the rotation-induced centrifugal acceleration and gravity effects are recorded in a strong-motion record. In this study we derive empirical relationships for rotation motion and its effects. Results show that rotation motion and its effects are small and can be ignored in weak motion, but they grow up very fast as the increasing of translation motion and become important in near-fault ground motions. We also found that those abnormal strong-motion records observed in near-fault are closely related to rotation motions.

  1. Multicellular Streaming in Solid Tumours

    NASA Astrophysics Data System (ADS)

    Kas, Josef

    As early as 400 BCE, the Roman medical encyclopaedist Celsus recognized that solid tumours are stiffer than surrounding tissue. However, cancer cell lines are softer, and softer cells facilitate invasion. This paradox raises several questions: Does softness emerge from adaptation to mechanical and chemical cues in the external microenvironment, or are soft cells already present inside a primary solid tumour? If the latter, how can a more rigid tissue contain more soft cells? Here we show that in primary tumour samples from patients with mammary and cervix carcinomas, cells do exhibit a broad distribution of rigidities, with a higher fraction of softer and more contractile cells compared to normal tissue. Mechanical modelling based on patient data reveals that, surprisingly, tumours with a significant fraction of very soft cells can still remain rigid. Moreover, in tissues with the observed distributions of cell stiffnesses, softer cells spontaneously self-organize into lines or streams, possibly facilitating cancer metastasis.

  2. Streaming Analytics and Data Engineering

    SciTech Connect

    2016-06-06

    SADE is a software package for rapidly assembling analytic pipelines to manipulate data. The packages consists of the engine that manages the data and coordinates the movement of data between the tasks performing a function? a set of core libraries consisting of plugins that perform common tasks? and a framework to extend the system supporting the development of new plugins. Currently through configuration files, a pipeline can be defined that maps the routing of data through a series of plugins. Pipelines can be run in a batch mode or can process streaming data? they can be executed from the command line or run through a Windows background service. There currently exists over a hundred plugins, over fifty pipeline configurations? and the software is now being used by about a half-dozen projects.

  3. Mab's orbital motion explained

    NASA Astrophysics Data System (ADS)

    Kumar, K.; de Pater, I.; Showalter, M. R.

    2015-07-01

    We explored the hypothesis that Mab's anomalous orbital motion, as deduced from Hubble Space Telescope (HST) data (Showalter, M.R., Lissauer, J.J. [2006]. Science (New York, NY) 311, 973-977), is the result of gravitational interactions with a putative suite of large bodies in the μ-ring. We conducted simulations to compute the gravitational effect of Mab (a recently discovered Uranian moon) on a cloud of test particles. Subsequently, by employing the data extracted from the test particle simulations, we executed random walk simulations to compute the back-reaction of nearby perturbers on Mab. By generating simulated observation metrics, we compared our results to the data retrieved from the HST. Our results indicate that the longitude residual change noted in the HST data (Δλr,Mab ≈ 1 deg) is well matched by our simulations. The eccentricity variations (ΔeMab ≈10-3) are however typically two orders of magnitude too small. We present a variety of reasons that could account for this discrepancy. The nominal scenario that we investigated assumes a perturber ring mass (mring) of 1 mMab (Mab's mass) and a perturber ring number density (ρn,ring) of 10 perturbers per 3 RHill,Mab (Mab's Hill radius). This effectively translates to a few tens of perturbers with radii of approximately 2-3 km, depending on the albedo assumed. The results obtained also include an interesting litmus test: variations of Mab's inclination on the order of the eccentricity changes should be observable. Our work provides clues for further investigation into the tantalizing prospect that the Mab/μ-ring system is undergoing re-accretion after a recent catastrophic disruption.

  4. Human motion analysis and characterization

    NASA Astrophysics Data System (ADS)

    Cathcart, J. Michael; Prussing, Keith; Kocher, Brian

    2011-06-01

    Georgia Tech has investigated methods for the detection and tracking of personnel in a variety of acquisition environments. This research effort focused on a detailed phenomenological analysis of human physiology and signatures with the subsequent identification and characterization of potential observables. Both aspects are needed to support the development of personnel detection and tracking algorithms. As a fundamental part of this research effort, Georgia Tech collected motion capture data on an individual for a variety of walking speeds, carrying loads, and load distributions. These data formed the basis for deriving fundamental properties of the individual's motion and the derivation of motionbased observables, and changes in these fundamental properties arising from load variations. Analyses were conducted to characterize the motion properties of various body components such as leg swing, arm swing, head motion, and full body motion. This paper will describe the data acquisition process, extraction of motion characteristics, and analysis of these data. Video sequences illustrating the motion data and analysis results will also be presented.

  5. Muon motion in titanium hydride

    NASA Technical Reports Server (NTRS)

    Kempton, J. R.; Petzinger, K. G.; Kossler, W. J.; Schone, H. E.; Hitti, B. S.; Stronach, C. E.; Adu, N.; Lankford, W. F.; Reilly, J. J.; Seymour, E. F. W.

    1988-01-01

    Motional narrowing of the transverse-field muon spin rotation signal was observed in gamma-TiH(x) for x = 1.83, 1.97, and 1.99. An analysis of the data for TiH1.99 near room temperature indicates that the mechanism responsible for the motion of the muon out of the octahedral site is thermally activated diffusion with an attempt frequency comparable to the optical vibrations of the lattice. Monte Carlo calculations to simulate the effect of muon and proton motion upon the muon field-correlation time were used to interpret the motional narrowing in TiH1.97 near 500 K. The interpretation is dependent upon whether the Bloembergen, Purcell, and Pound (BPP) theory or an independent spin-pair relaxation model is used to obtain the vacancy jump rate from proton NMR T1 measurements. Use of BPP theory shows that the field-correction time can be obtained if the rate of motion of the muon with respect to the rate of the motion for the protons is decreased. An independent spin-pair relaxation model indicates that the field-correlation time can be obtained if the rate of motion for the nearest-neighbor protons is decreased.

  6. Open architecture CMM motion controller

    NASA Astrophysics Data System (ADS)

    Chang, David; Spence, Allan D.; Bigg, Steve; Heslip, Joe; Peterson, John

    2001-12-01

    Although initially the only Coordinate Measuring Machine (CMM) sensor available was a touch trigger probe, technological advances in sensors and computing have greatly increased the variety of available inspection sensors. Non-contact laser digitizers and analog scanning touch probes require very well tuned CMM motion control, as well as an extensible, open architecture interface. This paper describes the implementation of a retrofit CMM motion controller designed for open architecture interface to a variety of sensors. The controller is based on an Intel Pentium microcomputer and a Servo To Go motion interface electronics card. Motor amplifiers, safety, and additional interface electronics are housed in a separate enclosure. Host Signal Processing (HSP) is used for the motion control algorithm. Compared to the usual host plus DSP architecture, single CPU HSP simplifies integration with the various sensors, and implementation of software geometric error compensation. Motion control tuning is accomplished using a remote computer via 100BaseTX Ethernet. A Graphical User Interface (GUI) is used to enter geometric error compensation data, and to optimize the motion control tuning parameters. It is shown that this architecture achieves the required real time motion control response, yet is much easier to extend to additional sensors.

  7. Forensics of subhalo-stream encounters: the three phases of gap growth

    NASA Astrophysics Data System (ADS)

    Erkal, Denis; Belokurov, Vasily

    2015-06-01

    There is hope to discover dark matter subhaloes free of stars (predicted by the current theory of structure formation) by observing gaps they produce in tidal streams. In fact, this is the most promising technique for dark substructure detection and characterization as such gaps grow with time, magnifying small perturbations into clear signatures observable by ongoing and planned Galaxy surveys. To facilitate such future inference, we develop a comprehensive framework for studies of the growth of the stream density perturbations. Starting with simple assumptions and restricting to streams on circular orbits, we derive analytic formulae that describe the evolution of all gap properties (size, density contrast, etc.) at all times. We uncover complex, previously unnoticed behaviour, with the stream initially forming a density enhancement near the subhalo impact point. Shortly after, a gap forms due to the relative change in period induced by the subhalo's passage. There is an intermediate regime where the gap grows linearly in time. At late times, the particles in the stream overtake each other, forming caustics, and the gap grows like √{t}. In addition to the secular growth, we find that the gap oscillates as it grows due to epicyclic motion. We compare this analytic model to N-body simulations and find an impressive level of agreement. Importantly, when analysing the observation of a single gap we find a large degeneracy between the subhalo mass, the impact geometry and kinematics, the host potential, and the time since flyby.

  8. Enhanced electroporation in plant tissues via low frequency pulsed electric fields: influence of cytoplasmic streaming.

    PubMed

    Asavasanti, Suvaluk; Stroeve, Pieter; Barrett, Diane M; Jernstedt, Judith A; Ristenpart, William D

    2012-01-01

    Pulsed electric fields (PEF) are known to be effective at permeabilizing plant tissues. Prior research has demonstrated that lower pulse frequencies induce higher rates of permeabilization, but the underlying reason for this response is unclear. Intriguingly, recent microscopic observations with onion tissues have also revealed a correlation between PEF frequency and the subsequent speed of intracellular convective motion, i.e., cytoplasmic streaming. In this paper, we investigate the effect of cytoplasmic streaming on the efficacy of plant tissue permeabilization via PEF. Onion tissue samples were treated with Cytochalasin B, a known inhibitor of cytoplasmic streaming, and changes in cellular integrity and viability were measured over a wide range of frequencies and field strengths. We find that at low frequencies (f < 1 Hz), the absence of cytoplasmic streaming results in a 19% decrease in the conductivity disintegration index compared with control samples. Qualitatively, similar results were observed using a microscopic cell viability assay. The results suggest that at low frequencies convection plays a statistically significant role in distributing more conductive fluid throughout the tissue, making subsequent pulses more efficacious. The key practical implication is that PEF pretreatment at low frequency can increase the rate of tissue permeabilization in dehydration or extraction processes, and that the treatment will be most effective when cytoplasmic streaming is most active, i.e., with freshly prepared plant tissues.

  9. Acoustic streaming produced by a cylindrical bubble undergoing volume and translational oscillations in a microfluidic channel.

    PubMed

    Doinikov, Alexander A; Combriat, Thomas; Thibault, Pierre; Marmottant, Philippe

    2016-09-01

    A theoretical model is developed for acoustic streaming generated by a cylindrical bubble confined in a fluid channel between two planar elastic walls. The bubble is assumed to undergo volume and translational oscillations. The volume oscillation is caused by an imposed acoustic pressure field and generates the bulk scattered wave in the fluid gap and Lamb-type surface waves propagating along the fluid-wall interfaces. The translational oscillation is induced by the velocity field of an external sound source such as another bubble or an oscillatory fluid flow. The acoustic streaming is assumed to result from the interaction of the volume and the translational modes of the bubble oscillations. The general solutions for the linear equations of fluid motion and the equations of acoustic streaming are calculated with no restrictions on the ratio between the viscous penetration depth and the bubble size. Approximate solutions for the limit of low viscosity are provided as well. Simulations of streamline patterns show that the geometry of the streaming resembles flows generated by a source dipole, while the vortex orientation is governed by the driving frequency, bubble size, and the distance of the bubble from the source of translational excitation. Experimental verification of the developed theory is performed using data for streaming generated by bubble pairs.

  10. Basal characteristics of the main sticky spot on the ice plain of Whillans Ice Stream, Antarctica

    NASA Astrophysics Data System (ADS)

    Luthra, Tarun; Anandakrishnan, Sridhar; Winberry, J. Paul; Alley, Richard B.; Holschuh, Nicholas

    2016-04-01

    Understanding the processes that affect streaming ice flow and the mass balance of glaciers and ice sheets requires sound knowledge of their subglacial environments. Previous studies have shown that an extensive deformable subglacial sediment layer favors fast ice-stream flow. However, areas of high basal drag, termed sticky spots, are of particular interest because they inhibit the fast flow of the overriding ice. The stick-slip behavior of Whillans Ice Stream (WIS) is perhaps the most conspicuous manifestation of a subglacial sticky spot. We present new ice-thickness and seismic-reflection measurements collected over the main sticky spot in the ice plain of WIS, allowing us to elucidate its role in the behavior of the ice stream. Ice-thickness and surface-elevation data show that the sticky spot occupies a subglacial topographic high. Water flow in response to the hydrological potential gradient will be routed around the sticky spot if effective pressures are similar on the sticky spot and elsewhere. The seismic experiment imaged a laterally continuous basal layer approximately 6 m thick, having compressional wave velocities of greater than 1800 m s-1 and density greater than 1800 kg m-3, indicative of a till layer that is stiffer than corresponding till beneath well-lubricated parts of the ice stream. This layer likely continues to deform under the higher shear stress of the sticky spot, and some water may be pumped up onto the sticky spot during motion events.

  11. Acoustic streaming produced by a cylindrical bubble undergoing volume and translational oscillations in a microfluidic channel

    NASA Astrophysics Data System (ADS)

    Doinikov, Alexander A.; Combriat, Thomas; Thibault, Pierre; Marmottant, Philippe

    2016-09-01

    A theoretical model is developed for acoustic streaming generated by a cylindrical bubble confined in a fluid channel between two planar elastic walls. The bubble is assumed to undergo volume and translational oscillations. The volume oscillation is caused by an imposed acoustic pressure field and generates the bulk scattered wave in the fluid gap and Lamb-type surface waves propagating along the fluid-wall interfaces. The translational oscillation is induced by the velocity field of an external sound source such as another bubble or an oscillatory fluid flow. The acoustic streaming is assumed to result from the interaction of the volume and the translational modes of the bubble oscillations. The general solutions for the linear equations of fluid motion and the equations of acoustic streaming are calculated with no restrictions on the ratio between the viscous penetration depth and the bubble size. Approximate solutions for the limit of low viscosity are provided as well. Simulations of streamline patterns show that the geometry of the streaming resembles flows generated by a source dipole, while the vortex orientation is governed by the driving frequency, bubble size, and the distance of the bubble from the source of translational excitation. Experimental verification of the developed theory is performed using data for streaming generated by bubble pairs.

  12. The Cross-Stream Structure of the Crests of Breaking Waves

    NASA Astrophysics Data System (ADS)

    Duncan, J. H.; Diorio, J. D.; Liu, X.

    2008-11-01

    Surface profiles and flow fields in the crests of breaking waves are usually measured in vertical stream-wise planes. However, measurements of the turbulent flow in boundary layers along flat rigid walls have indicated the importance of streamwise flow structures. In the present study, breaking waves are examined in a tank that is 12.8 m long and 1.2 m wide with a water depth of 0.91 m. A programmable wave maker is used to generate wave packets (central frequencies 1.15 - 1.42 Hz) that create breakers by dispersive focusing. Different amplitudes of the wave maker motion are used to generate various breaking waves ranging from weakly spilling to plunging breakers. A cinematic 2D LIF technique is used to measure the crest profile histories and the light-sheet plane is oriented to measure both the stream-wise and cross-stream crest profiles in separate experiments. It is found that the development of ripples due to turbulence-free surface interactions is highly repeatable and that even though the waves are two-dimensional before breaking, the amplitude of the cross-stream components quickly reaches 50% of the stream-wise ripple amplitude.

  13. Towards adaptive, streaming analysis of x-ray tomography data

    SciTech Connect

    Thomas, Mathew; Kleese van Dam, Kerstin; Marshall, Matthew J.; Kuprat, Andrew P.; Carson, James P.; Lansing, Carina S.; Guillen, Zoe C.; Miller, Erin A.; Lanekoff, Ingela; Laskin, Julia

    2015-03-04

    Temporal and spatial resolution of chemical imaging methodologies such as x-ray tomography are rapidly increasing, leading to more complex experimental procedures and fast growing data volumes. Automated analysis pipelines and big data analytics are becoming essential to effectively evaluate the results of such experiments. Offering those data techniques in an adaptive, streaming environment can further substantially improve the scientific discovery process, by enabling experimental control and steering based on the evaluation of emerging phenomena as they are observed by the experiment. Pacific Northwest National Laboratory (PNNL)’ Chemical Imaging Initiative (CII - http://imaging.pnnl.gov/ ) has worked since 2011 towards developing a framework that allows users to rapidly compose and customize high throughput experimental analysis pipelines for multiple instrument types. The framework, named ‘Rapid Experimental Analysis’ (REXAN) Framework [1], is based on the idea of reusable component libraries and utilizes the PNNL developed collaborative data management and analysis environment ‘Velo’, to provide a user friendly analysis and data management environment for experimental facilities. This article will, discuss the capabilities established for X-Ray tomography, discuss lessons learned, and provide an overview of our more recent work in the Analysis in Motion Initiative (AIM - http://aim.pnnl.gov/ ) at PNNL to provide REXAN capabilities in a streaming environment.

  14. Flexible flapping wings can exhibit quasi-periodic motion!

    NASA Astrophysics Data System (ADS)

    Bose, Chandan; Sarkar, Sunetra

    2016-10-01

    The dynamics of a flexible flapping wing is investigated by modelling it as a coupled nonlinear fluid-structure interaction (FSI) system in the low Reynolds number flow regime in accordance to the flight of flapping wing micro air vehicles (MAVs). A bifurcation analysis, by varying the free-stream wind velocity (U ∞) as the control parameter, revealed the presence of a new dynamics in the form of a quasi-periodic attractor in the flapping wing motion. The structural and aerodynamic nonlinearities present in the system cause a supercritical Hopf bifurcation, where stable limit cycle oscillation emerges from fixed point response beyond a critical value of the free-stream velocity. Further increasing the control parameter, another bifurcation named Neimark-Sacker bifurcation takes place and as a result, the flapping wing exhibits quasi-periodic motion. The presence of Neimark-Sacker bifurcation in the flapping flow-field dynamics is an interesting find and the present work focuses on it's associated dynamical behaviour. Various dynamical system tools like frequency spectra, phase space, Poincaré section, first return map have been implemented successfully to confirm the presence of quasi-periodicity.

  15. A database of macromolecular motions.

    PubMed Central

    Gerstein, M; Krebs, W

    1998-01-01

    We describe a database of macromolecular motions meant to be of general use to the structural community. The database, which is accessible on the World Wide Web with an entry point at http://bioinfo.mbb.yale.edu/MolMovDB , attempts to systematize all instances of protein and nucleic acid movement for which there is at least some structural information. At present it contains >120 motions, most of which are of proteins. Protein motions are further classified hierarchically into a limited number of categories, first on the basis of size (distinguishing between fragment, domain and subunit motions) and then on the basis of packing. Our packing classification divides motions into various categories (shear, hinge, other) depending on whether or not they involve sliding over a continuously maintained and tightly packed interface. In addition, the database provides some indication about the evidence behind each motion (i.e. the type of experimental information or whether the motion is inferred based on structural similarity) and attempts to describe many aspects of a motion in terms of a standardized nomenclature (e.g. the maximum rotation, the residue selection of a fixed core, etc.). Currently, we use a standard relational design to implement the database. However, the complexity and heterogeneity of the information kept in the database makes it an ideal application for an object-relational approach, and we are moving it in this direction. Specifically, in terms of storing complex information, the database contains plausible representations for motion pathways, derived from restrained 3D interpolation between known endpoint conformations. These pathways can be viewed in a variety of movie formats, and the database is associated with a server that can automatically generate these movies from submitted coordinates. PMID:9722650

  16. Neural mechanisms of motion sickness

    NASA Technical Reports Server (NTRS)

    Crampton, G. H.; Daunton, N. G.

    1983-01-01

    The possibility that there might be a neuro-homoral cerebrospinal fluid link in motion sickness was directly tested by blocking the flow of CSF from the third into the fourth ventricle in cats. Evidence obtained thus far is consistent with the hypothesis. Cats with demonstrably sound plugs did not vomit in response to an accelerative motion sickness stimulus, whereas cats with imperfect 'leaky' plugs vomited with little or no delay in latency. Althoough there are several putative candidates, the identification of a humoral motion sickness substance is a matter of conjecture.

  17. Streaming for Mathematics in Victorian Secondary Schools

    ERIC Educational Resources Information Center

    Forgasz, Helen

    2010-01-01

    Streaming (or ability grouping) for mathematics learning is a contentious issue. It can also be considered an issue of equity or social justice as some students may be adversely affected by the practice. Currently, the Victorian Department of Education and Early Childhood Development (DEECD) does not appear to have clear guidelines on streaming.…

  18. Revealing the dual streams of speech processing

    PubMed Central

    Fridriksson, Julius; Yourganov, Grigori; Bonilha, Leonardo; Basilakos, Alexandra; Rorden, Christopher

    2016-01-01

    Several dual route models of human speech processing have been proposed suggesting a large-scale anatomical division between cortical regions that support motor–phonological aspects vs. lexical–semantic aspects of speech processing. However, to date, there is no complete agreement on what areas subserve each route or the nature of interactions across these routes that enables human speech processing. Relying on an extensive behavioral and neuroimaging assessment of a large sample of stroke survivors, we used a data-driven approach using principal components analysis of lesion-symptom mapping to identify brain regions crucial for performance on clusters of behavioral tasks without a priori separation into task types. Distinct anatomical boundaries were revealed between a dorsal frontoparietal stream and a ventral temporal–frontal stream associated with separate components. Collapsing over the tasks primarily supported by these streams, we characterize the dorsal stream as a form-to-articulation pathway and the ventral stream as a form-to-meaning pathway. This characterization of the division in the data reflects both the overlap between tasks supported by the two streams as well as the observation that there is a bias for phonological production tasks supported by the dorsal stream and lexical–semantic comprehension tasks supported by the ventral stream. As such, our findings show a division between two processing routes that underlie human speech processing and provide an empirical foundation for studying potential computational differences that distinguish between the two routes. PMID:27956600

  19. INDICATORS OF HYDROLOGIC PERMANENCE IN HEADWATER STREAMS

    EPA Science Inventory

    Headwater intermittent streams lie at the aquatic-terrestrial interface and represent much of our nation's stream miles. Recent court cases concerning the definition of jurisdictional waters under the Clean Water Act have illuminated a need to better understand the characteristi...

  20. COHO SALMON DEPENDENCE ON INTERMITTENT STREAMS

    EPA Science Inventory

    In February 2006, the US Supreme Court heard cases that may affect whether intermittent streams are jurisdictional waters under the Clean Water Act. In June 2006, however, the cases were remanded to the circuit court, leaving the status of intermittent streams uncertain once agai...

  1. The Gulf Stream and Density of Fluids

    ERIC Educational Resources Information Center

    Landstrom, Erich

    2006-01-01

    A few kilometers from the shores of Palm Beach County, Florida, is the Gulf Stream current--a remarkable "river" within an ocean. The current's journey across the Atlantic Ocean connects southeast Florida and southwest Great Britain as it streams steadily north at speeds of 97 km a day; moving 100 times as much water as all the rivers on…

  2. COMPARTMENTAL MODEL OF NITRATE RETENTION IN STREAMS

    EPA Science Inventory

    A compartmental modeling approach is presented to route nitrate retention along a cascade of stream reach sections. A process transfer function is used for transient storage equations with first order reaction terms to represent nitrate uptake in the free stream, and denitrifica...

  3. Incomplete Mixing in a Small, Urban stream

    NASA Astrophysics Data System (ADS)

    Ryan, R. J.; Boufadel, M. C.

    2006-05-01

    Conservative solute tracer experiments were conducted in Indian Creek, a small urban stream located in Philadelphia, Pennsylvania, USA. Estimated flow rates were between 46 L s-1 and 81 L s-1, average stream width was 5.5 m and average stream depth was 0.2 m. Given these dimensions, most researchers would think it reasonable to assume that the stream is completely mixed vertically and horizontally. However, we found that the stream was not vertically completely mixed in a 0.95 m deep, 30 m long pool. The limited mixing was demonstrated by the vertical stratification of a tracer cloud which was completely mixed both laterally and vertically across the stream prior to entering the pool. We suggest that the cause of limited mixing is due to a balance between groundwater inflow and transverse dispersion at the cross section. We show that the unsupported assumption of complete mix may result in a wide range, and thus increased uncertainty, of the values of stream flow and longitudinal dispersion coefficient estimated from these data. We conclude that the assumption of complete mix and one-dimensional modeling must be checked against actual field conditions, even in small streams.

  4. Effects of Context on Auditory Stream Segregation

    ERIC Educational Resources Information Center

    Snyder, Joel S.; Carter, Olivia L.; Lee, Suh-Kyung; Hannon, Erin E.; Alain, Claude

    2008-01-01

    The authors examined the effect of preceding context on auditory stream segregation. Low tones (A), high tones (B), and silences (-) were presented in an ABA-pattern. Participants indicated whether they perceived 1 or 2 streams of tones. The A tone frequency was fixed, and the B tone was the same as the A tone or had 1 of 3 higher frequencies.…

  5. Stabilization of tokamak plasma by lithium streams

    SciTech Connect

    L.E. Zakharov

    2000-08-07

    The stabilization theory of free-boundary magnetohydrodynamic instabilities in tokamaks by liquid lithium streams driven by magnetic propulsion is formulated. While the conventional, wall-locked, resistive wall mode can be well suppressed by the flow, a new, stream-locked mode determines the limits of the flow stabilization.

  6. Ecosystem Services Provided by Stream Fishes

    EPA Science Inventory

    Stream fish provide important services to people, including recreation and food, regulation of ecosystem processes, and aesthetic benefits. If the services provided by fish in different streams can be measured, then they can be valued and considered in restoration decisions. We...

  7. National River and Stream Assessment Monitoring Design

    EPA Science Inventory

    The USEPA designed the National River and Stream Assessment (NRSA) in 2007 and field sampling was completed in 2008-9. The objective of the assessment is to estimate the ecological condition of river and streams nationally. This paper describes the national survey design and re...

  8. Method for recovering metal from waste stream

    SciTech Connect

    Greenberg, B.

    1991-09-10

    This patent describes a method for recovering metal from a waste stream to render the waste stream suitable for discharge. It comprises passing a waste stream comprised of heavy metal salts in dilute solution into a cathode chamber of an anion exchange membrane delineated electrolytic cell, wherein the metals are selected from the group having a standard reduction potential more negative than that of hydrogen in the electromotive force series and the heavy metal ion concentration of the solution is less than about 10,000 parts per million of dissolved material; subjecting the waste stream to high current density electrolysis at up to about 25 volts to enhance the controlled regular formation of a noncompressible metal hydrous oxide crystalline precipitate in the cathode chamber; separating the precipitate from the waste stream; and splitting the clarified liquid waste stream so that a portion of the clarified liquid waste stream is discharged and a portion is returned downstream for commingling with the metal ion-containing waste stream for further treatment.

  9. Flooding in ephemeral streams: incorporating transmission losses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stream flow in semiarid lands commonly occurs as a form of flash floods in dry ephemeral stream beds. The goal of this research is to couple hydrological and hydraulic models treats channel transmission losses and test the methodology in the USDA-ARS Walnut Gulch Experimental Watershed (WGEW). For h...

  10. Key stream/sediment exchanges of water and heat near stream mouths

    NASA Astrophysics Data System (ADS)

    Constantz, J. E.; Naranjo, R. C.; Niswonger, R. G.; Neilson, B. T.; Allander, K.; Zamora, C.; Smith, D. W.; Stonestrom, D. A.

    2014-12-01

    The section of stream discharging to a lake or other surface-water body is referred to as the stream mouth, a stream reach with rapidly changing hydrologic conditions, leading to unique aquatic and benthic ecology, as well as a visibly active fishery habitat. Of environmental significance, bridges, control structures, channelization and foot traffic are common near stream mouths, warranting comparisons of natural and channelized stream mouths. The present work completes the first investigation focusing specifically on the hydrology of surface-water/sediment exchanges at stream-mouth reaches discharging to lakes and compares these exchanges to those measured along the nearby shoreline in both a qualitative and quantitative manner. Heat and water exchanges for two common types of stream mouths (a natural stream with a summer barrier bar and a channelized stream mouth) are compared with comparable exchanges along the nearby shoreline on the north shore of Lake Tahoe located in the Central Sierra Nevada Mountain Range (CA/NV, US). The study site was selected partially due the abundance of streams discharging into the lake of both a natural and channelized nature (~30 small streams with a large number of both types of stream mouths). Heat and water exchanges were both qualitatively and quantitatively distinct for the three types of hydrologic settings, with (1) cool, low velocity, longitudinal (hyporheic) flowpaths observed below the channelized stream mouth, discharging beneath the warmer, more buoyant lakeshore water, (2) the nearby shoreline receiving relatively warm, higher velocity discharge and (3) for the natural stream mouth, there was strong diurnal temperature pattern in groundwater discharging through the seasonal barrier beach to the lake. Impacts of strong 2013 wave action on exchanges were also distinct for the three settings, with (1) channelization allowing waves to extend well upstream, (2) a lesser invasive impact in the shoreline swash zone exchanges

  11. Effects of urbanization and urban stream restoration on the physical and biological structure of stream ecosystems.

    PubMed

    Violin, Christy R; Cada, Peter; Sudduth, Elizabeth B; Hassett, Brooke A; Penrose, David L; Bernhardt, Emily S

    2011-09-01

    Streams, as low-lying points in the landscape, are strongly influenced by the stormwaters, pollutants, and warming that characterize catchment urbanization. River restoration projects are an increasingly popular method for mitigating urban insults. Despite the growing frequency and high expense of urban stream restoration projects, very few projects have been evaluated to determine whether they can successfully enhance habitat structure or support the stream biota characteristic of reference sites. We compared the physical and biological structure of four urban degraded, four urban restored, and four forested streams in the Piedmont region of North Carolina to quantify the ability of reach-scale stream restoration to restore physical and biological structure to urban streams and to examine the assumption that providing habitat is sufficient for biological recovery. To be successful at mitigating urban impacts, the habitat structure and biological communities found in restored streams should be more similar to forested reference sites than to their urban degraded counterparts. For every measured reach- and patch-scale attribute, we found that restored streams were indistinguishable from their degraded urban stream counterparts. Forested streams were shallower, had greater habitat complexity and median sediment size, and contained less-tolerant communities with higher sensitive taxa richness than streams in either urban category. Because heavy machinery is used to regrade and reconfigure restored channels, restored streams had less canopy cover than either forested or urban streams. Channel habitat complexity and watershed impervious surface cover (ISC) were the best predictors of sensitive taxa richness and biotic index at the reach and catchment scale, respectively. Macroinvertebrate communities in restored channels were compositionally similar to the communities in urban degraded channels, and both were dissimilar to communities in forested streams. The

  12. Satellite imagery of the onset of streaming flow of ice streams C and D, West Antarctica

    USGS Publications Warehouse

    Hodge, S.M.; Doppelhammer, S.K.

    1996-01-01

    Five overlapping Landsat multispectral scanner satellite images of the interior of the West Antarctic ice sheet were enhanced with principal component analysis, high-pass filtering, and linear contrast stretching and merged into a mosaic by aligning surface features in the overlap areas. The mosaic was registered to geodetic coordinates, to an accuracy of about 1 km, using the five scene centers as control points. The onset of streaming flow of two tributaries of ice stream C and one tributary of ice stream D is visible in the mosaic. The onset appears to occur within a relatively short distance, less than the width of the ice stream, typically at a subglacial topographic feature such as a step or ridge. The ice streams extend farther up into the interior than previously mapped. Ice stream D starts about 150 km from the ice divide, at an altitude of about 1500 m, approximately halfway up the convex-upward dome shape of the interior ice sheet. Ice stream D is relatively much longer than ice stream C, possibly because ice stream D is currently active whereas ice stream C is currently inactive. The grounded portion of the West Antarctic ice sheet is perhaps best conceptualized as an ice sheet in which ice streams are embedded over most of its area, with slow moving ice converging into fast moving ice streams in a widely distributed pattern, much like that of streams and rivers in a hydrologic basin. A relic margin appears to parallel most of the south margin of the tributary of ice stream D, separated from the active shear margin by about 10 km or less for a distance of over 200 km. This means there is now evidence for recent changes having occurred in three of the five major ice streams which drain most of West Antarctica (B, C, and D), two of which (B and D) are currently active.

  13. On the age and formation mechanism of the core of the Quadrantid meteoroid stream

    NASA Astrophysics Data System (ADS)

    Abedin, Abedin; Spurný, Pavel; Wiegert, Paul; Pokorný, Petr; Borovička, Jiří; Brown, Peter

    2015-11-01

    The Quadrantid meteor shower is among the strongest annual meteor showers, and has drawn the attention of scientists for several decades. The stream is unusual, among others, for several reasons: its very short duration around maximum activity (≈12-14 h) as detected by visual, photographic and radar observations, its recent onset (around 1835 AD Quetelet, L.A.J. [1839]. Catalogue des principles apparitions d'etoiles filantes) and because it had been the only major stream without an obvious parent body until 2003. Ever since, there have been debates as to the age of the stream and the nature of its proposed parent body, asteroid 2003 EH1. In this work, we present results on the most probable age and formation mechanism of the narrow portion of the Quadrantid meteoroid stream. For the first time we use data on eight high precision photographic Quadrantids, equivalent to gram-kilogram size, to constrain the most likely age of the core of the stream. Out of eight high-precision photographic Quadrantids, five pertain directly to the narrow portion of the stream. In addition, we also use data on five high-precision radar Quadrantids, observed within the peak of the shower. We performed backwards numerical integrations of the equations of motion of a large number of 'clones' of both, the eight high-precision photographic and five radar Quadrantid meteors, along with the proposed parent body, 2003 EH1. According to our results, from the backward integrations, the most likely age of the narrow structure of the Quadrantids is between 200 and 300 years. These presumed ejection epochs, corresponding to 1700-1800 AD, are then used for forward integrations of large numbers of hypothetical meteoroids, ejected from the parent 2003 EH1, until the present epoch. The aim is to constrain whether the core of the Quadrantid meteoroid stream is consistent with a previously proposed relatively young age (≈200 years).

  14. Modeling Strike-Slip-Driven Stream Capture in Detachment- and Transport-Limited Fluvial Systems

    NASA Astrophysics Data System (ADS)

    Harbert, S.; Duvall, A. R.; Tucker, G. E.

    2014-12-01

    Rivers, especially those in mountainous settings, are known to respond to tectonic and climatic drivers through both gradual and abrupt changes in slope, hydraulic geometry, and planform. Modification of drainage network topology by stream capture, in which drainage area, and therefore water and sediment, is diverted suddenly from one catchment into another, represents the rapid end of the fluvial response spectrum. Such sudden drainage rearrangement affects the river's potential for incision and sediment transport, and thus has implications for the development of topography and for depositional histories in sedimentary basins. Despite recognition of the importance of this process in landscape evolution, the factors controlling the occurrence of stream capture are not well understood. Here we investigate the process of stream capture using strike-slip faults as a natural experiment. Lateral fault motion drives stream capture when offset is enough to juxtapose adjacent fault-perpendicular streams. In the simplest scenario, the capture events should occur regularly in space and time whenever two streams are juxtaposed, the frequency of capture depending only on drainage spacing and fault slip rate. However, in real-world settings such as the San Andreas Fault Zone of California and the Marlborough Fault System of New Zealand, such regularity is not always observed. We use the Channel-Hillslope Integrated Landscape Development Model (CHILD) to investigate the mechanisms and frequency of stream capture in a strike-slip setting. Models are designed to address the connection between the size (i.e. drainage area) of juxtaposed rivers and the likelihood that capture will occur between them. We also explore the role of sediment load in the capture process by modeling both detachment-limited and transport-limited systems. Comparison of these model results to case-study field sites will help us to interpret the landscape signature of strike-slip faulting, and to understand

  15. Stream dynamics at pipeline river crossings

    SciTech Connect

    Beckstead, G.R.E.; Cavers, D.S.

    1996-12-31

    Pipeline crossings of streams, whether large or small, must consider the ability of the stream channel to scour its bed and erode its banks. Case studies are presented to illustrate the kinds of dynamic environments which must be considered in designing pipeline stream crossings. These characteristics may be determined through the use of comparative historical aerial photography and site photographs and surveys. The case studies presented as examples in this paper include gullies, bedrock-lined channels, entrenched meandering streams, multi-channel wandering streams, degrading channels, alluvial fans, and major channels affected by regulation and man-made structures. Natural hazards such as debris jams and beaver dams are also discussed. For each case study, the characteristics of the channels are described, the design approach discussed and site-specific constraints presented which affected the final design.

  16. The ecology and biogeochemistry of stream biofilms.

    PubMed

    Battin, Tom J; Besemer, Katharina; Bengtsson, Mia M; Romani, Anna M; Packmann, Aaron I

    2016-04-01

    Streams and rivers form dense networks, shape the Earth's surface and, in their sediments, provide an immensely large surface area for microbial growth. Biofilms dominate microbial life in streams and rivers, drive crucial ecosystem processes and contribute substantially to global biogeochemical fluxes. In turn, water flow and related deliveries of nutrients and organic matter to biofilms constitute major constraints on microbial life. In this Review, we describe the ecology and biogeochemistry of stream biofilms and highlight the influence of physical and ecological processes on their structure and function. Recent advances in the study of biofilm ecology may pave the way towards a mechanistic understanding of the effects of climate and environmental change on stream biofilms and the biogeochemistry of stream ecosystems.

  17. Describing Story Evolution from Dynamic Information Streams

    SciTech Connect

    Rose, Stuart J.; Butner, R. Scott; Cowley, Wendy E.; Gregory, Michelle L.; Walker, Julia

    2009-10-12

    Sources of streaming information, such as news syndicates, publish information continuously. Information portals and news aggregators list the latest information from around the world enabling information consumers to easily identify events in the past 24 hours. The volume and velocity of these streams causes information from prior days’ to quickly vanish despite its utility in providing an informative context for interpreting new information. Few capabilities exist to support an individual attempting to identify or understand trends and changes from streaming information over time. The burden of retaining prior information and integrating with the new is left to the skills, determination, and discipline of each individual. In this paper we present a visual analytics system for linking essential content from information streams over time into dynamic stories that develop and change over multiple days. We describe particular challenges to the analysis of streaming information and explore visual representations for showing story change and evolution over time.

  18. Comet Machholz and the Quadrantid meteor stream

    NASA Astrophysics Data System (ADS)

    Jones, J.; Jones, W.

    1993-04-01

    Until quite recently, the Quadrantid meteor stream was considered to be an 'orphan'. Because of the difficulty in accounting for the large difference in the longitudes of the ascending nodes, McIntosh (1990) suggested that Comet Machholz and the stream have a sibling rather than a parent-child relationship. Gonczi et al. (1992) proposed that gravitational perturbations by Jupiter may be amplified sufficiently by the 2:1 resonance of the stream with Jupiter to explain the difference in the longitudes of ascending nodes if the stream was born when the comet's perihelion distance was last at its minimum about 4000 yr ago. In this paper, we show by computer simulations that, if the comet was captured at its last close approach with Jupiter about 2200 yr ago, there has been sufficient time for the resulting stream to produce most of the features of the presently observed Quadrantid/Arietid/Southern Delta-Aquarid complex.

  19. Arsenic in stream sediments of northern Alabama

    USGS Publications Warehouse

    Goldhaber, M.B.; Irwin, Elise; Atkins, Brian; Lee, Lopaka; Black, D.D.; Zappia, Humbert; Hatch, Joe; Pashin, Jack; Barwick, L.H.; Cartwright, W.E.; Sanzolone, Rick; Rupert, Leslie; Kolker, Allan; Finkelman, Robert

    2001-01-01

    OVERVIEW OF ARSENIC IN STREAM SEDIMENTS The overall range of arsenic in the NURE stream sediments was from 0.3 to 44 mg/kg sediment (ppm) As in the sample data set. The mean value was 4.3 ppm with a standard deviation of 4.1 ppm. For comparison, the crustal abundance of arsenic is 1.8 ppm (Taylor, 1964). Shale is higher, with average values of 15 ppm. Coal samples from the entire USGS National Coal Resource Data System coal database (Finkelman, 1994) average 24 ppm arsenic. A study of stream sediments from throughout the U.S. by the USGS NAWQA program reported that the 75th percentile for arsenic in 541 stream sediments was 9.5 ppm (Rice, 1999). Given the relatively low crustal abundance of arsenic, a number of stream-sediment samples in this study may be considered geochemically anomalous in this element.

  20. Visual motion integration for perception and pursuit

    NASA Technical Reports Server (NTRS)

    Stone, L. S.; Beutter, B. R.; Lorenceau, J.

    2000-01-01

    To examine the relationship between visual motion processing for perception and pursuit, we measured the pursuit eye-movement and perceptual responses to the same complex-motion stimuli. We show that humans can both perceive and pursue the motion of line-figure objects, even when partial occlusion makes the resulting image motion vastly different from the underlying object motion. Our results show that both perception and pursuit can perform largely accurate motion integration, i.e. the selective combination of local motion signals across the visual field to derive global object motion. Furthermore, because we manipulated perceived motion while keeping image motion identical, the observed parallel changes in perception and pursuit show that the motion signals driving steady-state pursuit and perception are linked. These findings disprove current pursuit models whose control strategy is to minimize retinal image motion, and suggest a new framework for the interplay between visual cortex and cerebellum in visuomotor control.

  1. The velocity dispersion of the caustic network due to random motion of individual stars in the lensing galaxy

    NASA Technical Reports Server (NTRS)

    Kundik, Tomislav; Witt, Hans J.; Chang, Kyongae

    1993-01-01

    We present a method of computing the velocity distribution of the caustic network due to the random motion of stars in the lensing galaxy. This method is illustrated on the example of the two-point mass lens and then applied to a large sample of stars. We conclude that the proper motion of the stars increases significantly the frequency of the high magnification events in comparison with a static lens configuration with constant stream or constant bulk velocity. The stream velocity is the velocity of the star field relative to the global bulk velocity of the galaxy. We show that the global bulk and the stream velocity of the star field have to be considered separately for any microlensing situation. The higher the surface mass density of the stars in the lensing galaxy, the higher the influence of proper motion of stars on the statistics of high magnification events. The influence of a Gaussian velocity distribution of the stars in the lensing galaxy compared with a constant stream velocity of the stars increases the number of high magnification events by a factor 1.30 +/- 0.06 for a normalized surface density of the stars cr = 0.1 and by a factor 1.7 +/- 0.1 for sigma = 0.5. This means that for some microlensing situations the proper motion of the stars in a lensing galaxy has to be considered for exact microlensing predictions.

  2. In-stream Escherichia coli Modeling

    NASA Astrophysics Data System (ADS)

    Pandey, P.; Soupir, M.

    2013-12-01

    Elevated levels of pathogenic bacteria indicators such as Escherichia coli (E. coli) in streams are a serious concern. Controlling E. coli levels in streams requires improving our existing understanding of fate and transport of E. coli at watershed scale. In-stream E. coli concentrations are potentially linked to non-point pollution sources (i.e., agricultural land). Water of a natural stream can receive E. coli by either through overland flow (via runoff from cropland) or resuspension from the streambed to the water column. Calculating in-stream total E. coli loads requires estimation of particle attached bacteria as well free floating E. coli transport. Currently water quality models commonly used for predicting E. coli levels in stream water have limited capability for predicting E. coli levels in the water column as well as in the streambed sediment. The challenges in calculating in-stream E. coli levels include difficulties in modeling the complex interactions between sediment particles and E. coli. Here we have developed a watershed scale model (integrated with Soil and Water Assessment Tool (SWAT)), which involves calculation of particle attached E. coli, to predict in-stream E. coli concentrations. The proposed model predicts E. coli levels in streambed bed sediment as well as in the water column. An extensive in-stream E. coli monitoring was carried out to verify the model predictions, and results indicate that the model performed well. The study proposed here will improve understanding on in-stream bacterial contamination, and help improving existing water quality models for predicting pathogenic bacteria levels in ambient water bodies.

  3. Ebullitive methane emissions from oxygenated wetland streams.

    PubMed

    Crawford, John T; Stanley, Emily H; Spawn, Seth A; Finlay, Jacques C; Loken, Luke C; Striegl, Robert G

    2014-11-01

    Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr(-1) ; over 6400 km(2) ) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

  4. Unionville, Pennsylvania School's Stream Restoration Project

    NASA Astrophysics Data System (ADS)

    Madsen, S. M.

    2004-12-01

    For the past three years, students and Earth Club members of C.F. Patton Middle School and Unionville High School have been involved in a stream restoration and monitoring project along a tributary to the East Branch of the Red Clay Creek in Pennsylvania. The Red Clay is within the larger Christina River Basin watershed which drains to Delaware Bay. Total funding of \\$962.00 was awarded by the Unionville-Chadds Ford Education Foundation to purchase both stream monitoring equipment and native plant species for stream restoration. Nine science teachers in the school district received certification in stream monitoring by the Pennsylvania State Parks Division. Certification enables the science faculty and their students to enter monitoring data in a statewide stream database. The stream data includes: temperature, levels of dissolved oxygen and nutrients, pH, alkalinity, conductivity, and a complete biosurvey of invertebrates. In addition to ongoing monitoring, the Earth Club sponsored a name-the-stream contest. Quartz Creek was chosen for this previously unnamed tributary. Its' name was approved by the East Marlborough Township Supervisor in May, 2004 and was then submitted to the USGS' Board on Geographic Names. The Earth Club has also sponsored a stream restoration contest. Students in the middle school were encouraged to design a habitat along the stream banks that would keep sediment in-place, while encouraging wildlife. The stream was originally crowded with invasive multi-flora rose but this was removed with the help of parents and students over a two year period. The winning student poster was outstanding and native species were purchased and planted following the poster's design. The planting took place in May, 2004 with over 40 persons involved including 25 middle school and 8 high school students, teachers from the schools, administrators and employees of the Brandywine Conservancy, and Red Clay Valley and Brandywine Valley Associations, and graduate

  5. Ebullitive methane emissions from oxygenated wetland streams

    USGS Publications Warehouse

    Crawford, John T.; Stanley, Emily H.; Spawn, Seth A.; Finlay, Jacques C.; Striegl, Robert G.

    2014-01-01

    Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr−1; over 6400 km2) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

  6. A primer on motion visual evoked potentials.

    PubMed

    Heinrich, Sven P

    2007-03-01

    Motion visual evoked potentials (motion VEPs) have been used since the late 1960s to investigate the properties of human visual motion processing, and continue to be a popular tool with a possible future in clinical diagnosis. This review first provides a synopsis of the characteristics of motion VEPs and then summarizes important methodological aspects. A subsequent overview illustrates how motion VEPs have been applied to study basic functions of human motion processing and shows perspectives for their use as a diagnostic tool.

  7. StreamMap: Smooth Dynamic Visualization of High-Density Streaming Points.

    PubMed

    Li, Chenhui; Baciu, George; Yu, Han

    2017-02-13

    Interactive visualization of streaming points for real-time scatterplots and linear blending of correlation patterns is increasingly becoming the dominant mode of visual analytics for both big data and streaming data from active sensors and broadcasting media. To better visualize and interact with inter-stream patterns, it is generally necessary to smooth out gaps or distortions in the streaming data. Previous approaches either animate the points directly or present a sampled static heatmap. We propose a new approach, called StreamMap, to smoothly blend high-density streaming points and create a visual flow that emphasizes the density pattern distributions. In essence, we present three new contributions for the visualization of high-density streaming points. The first contribution is a density-based method called super kernel density estimation that aggregates streaming points using an adaptive kernel to solve the overlapping problem. The second contribution is a robust density morphing algorithm that generates several smooth intermediate frames for a given pair of frames. The third contribution is a trend representation design that can help convey the flow directions of the streaming points. The experimental results on three datasets demonstrate the effectiveness of StreamMap when dynamic visualization and visual analysis of trend patterns on streaming points are required.

  8. Experimental investigation of acoustic streaming in a cylindrical wave guide up to high streaming Reynolds numbers.

    PubMed

    Reyt, Ida; Bailliet, Hélène; Valière, Jean-Christophe

    2014-01-01

    Measurements of streaming velocity are performed by means of Laser Doppler Velocimetry and Particle Image Velociimetry in an experimental apparatus consisting of a cylindrical waveguide having one loudspeaker at each end for high intensity sound levels. The case of high nonlinear Reynolds number ReNL is particularly investigated. The variation of axial streaming velocity with respect to the axial and to the transverse coordinates are compared to available Rayleigh streaming theory. As expected, the measured streaming velocity agrees well with the Rayleigh streaming theory for small ReNL but deviates significantly from such predictions for high ReNL. When the nonlinear Reynolds number is increased, the outer centerline axial streaming velocity gets distorted towards the acoustic velocity nodes until counter-rotating additional vortices are generated near the acoustic velocity antinodes. This kind of behavior is followed by outer streaming cells only and measurements in the near wall region show that inner streaming vortices are less affected by this substantial evolution of fast streaming pattern. Measurements of the transient evolution of streaming velocity provide an additional insight into the evolution of fast streaming.

  9. Stream-subsurface nutrient dynamics in a groundwater-fed stream

    NASA Astrophysics Data System (ADS)

    Rezanezhad, F.; Niederkorn, A.; Parsons, C. T.; Van Cappellen, P.

    2015-12-01

    The stream-riparian-aquifer interface plays a major role in the regional flow of nutrients and contaminants due to a strong physical-chemical gradient that promotes the transformation, retention, elimination or release of biogenic elements. To better understand the effect of the near-stream zones on stream biogeochemistry, we conducted a field study on a groundwater-fed stream located in the rare Charitable Research Reserve, Cambridge, Ontario, Canada. This study focused on monitoring the spatial and temporal distributions of nutrient elements within the riparian and hyporheic zones of the stream. Several piezometer nests and a series of passive (diffusion) water samplers, known as peepers, were installed along longitudinal and lateral transects centered on the stream to obtain data on the groundwater chemistry. Groundwater upwelling along the stream resulted in distinctly different groundwater types and associated nitrate concentrations between small distances in the riparian zone (<4m). After the upstream source of the stream surface water, concentrations of nutrients (NO3-, NH4+, SO42- and carbon) did not significantly change before the downstream outlet. Although reduction of nitrate and sulphate were found in the riparian zone of the stream, this did not significantly influence the chemistry of the adjacent stream water. Also, minimal retention in the hyporheic zones limited reduction of reactive compounds (NO3- and SO42-) within the stream channel. The results showed that the dissolved organic carbon (DOC) and residence time of water in the hyporheic zone and in surface water limited denitrification.

  10. Superdiffusive trajectories in Brownian motion.

    PubMed

    Duplat, Jérôme; Kheifets, Simon; Li, Tongcang; Raizen, Mark G; Villermaux, Emmanuel

    2013-02-01

    The Brownian motion of a microscopic particle in a fluid is one of the cornerstones of statistical physics and the paradigm of a random process. One of the most powerful tools to quantify it was provided by Langevin, who explicitly accounted for a short-time correlated "thermal" force. The Langevin picture predicts ballistic motion, ~t(2) at short-time scales, and diffusive motion ~t at long-time scales, where x is the displacement of the particle during time t, and the average is taken over the thermal distribution of initial conditions. The Langevin equation also predicts a superdiffusive regime, where ~t(3), under the condition that the initial velocity is fixed rather than distributed thermally. We analyze the motion of an optically trapped particle in air and indeed find t(3) dispersion. This observation is a direct proof of the existence of the random, rapidly varying force imagined by Langevin.

  11. Projectile Motion in Special Relativity.

    ERIC Educational Resources Information Center

    Naddy, Cory J.; Dudley, Scott C.; Haaland, Ryan K.

    2000-01-01

    Explains the motion that occurs when a particle with an initial velocity to the right is acted upon by a constant downward force. Considers what happens when the speed of the particle approaches the speed of light in particular. (WRM)

  12. Shaft-Motion-Analyzing System

    NASA Technical Reports Server (NTRS)

    Randall, Richard L.; Collins, John J.; Coleman, Paul T.; Roschak, Edmund J.

    1993-01-01

    Optoelectronic system to monitor motions of turbopump shaft developed. Optical sensors detect passage of reflective triangles on shaft. Optical measurements processed in real time into indications of speed of rotation and of axial and lateral displacements of shaft.

  13. Bayesian estimation of turbulent motion.

    PubMed

    Héas, Patrick; Herzet, Cédric; Mémin, Etienne; Heitz, Dominique; Mininni, Pablo D

    2013-06-01

    Based on physical laws describing the multiscale structure of turbulent flows, this paper proposes a regularizer for fluid motion estimation from an image sequence. Regularization is achieved by imposing some scale invariance property between histograms of motion increments computed at different scales. By reformulating this problem from a Bayesian perspective, an algorithm is proposed to jointly estimate motion, regularization hyperparameters, and to select the most likely physical prior among a set of models. Hyperparameter and model inference are conducted by posterior maximization, obtained by marginalizing out non--Gaussian motion variables. The Bayesian estimator is assessed on several image sequences depicting synthetic and real turbulent fluid flows. Results obtained with the proposed approach exceed the state-of-the-art results in fluid flow estimation.

  14. Is Diaphragm Motion a Good Surrogate for Liver Tumor Motion?

    SciTech Connect

    Yang, Juan; Cai, Jing; Wang, Hongjun; Chang, Zheng; Czito, Brian G.; Bashir, Mustafa R.; Palta, Manisha; Yin, Fang-Fang

    2014-11-15

    Purpose: To evaluate the relationship between liver tumor motion and diaphragm motion. Methods and Materials: Fourteen patients with hepatocellular carcinoma (10 of 14) or liver metastases (4 of 14) undergoing radiation therapy were included in this study. All patients underwent single-slice cine–magnetic resonance imaging simulations across the center of the tumor in 3 orthogonal planes. Tumor and diaphragm motion trajectories in the superior–inferior (SI), anterior–posterior (AP), and medial–lateral (ML) directions were obtained using an in-house-developed normalized cross-correlation–based tracking technique. Agreement between the tumor and diaphragm motion was assessed by calculating phase difference percentage, intraclass correlation coefficient, and Bland-Altman analysis (Diff). The distance between the tumor and tracked diaphragm area was analyzed to understand its impact on the correlation between the 2 motions. Results: Of all patients, the mean (±standard deviation) phase difference percentage values were 7.1% ± 1.1%, 4.5% ± 0.5%, and 17.5% ± 4.5% in the SI, AP, and ML directions, respectively. The mean intraclass correlation coefficient values were 0.98 ± 0.02, 0.97 ± 0.02, and 0.08 ± 0.06 in the SI, AP, and ML directions, respectively. The mean Diff values were 2.8 ± 1.4 mm, 2.4 ± 1.1 mm, and 2.2 ± 0.5 mm in the SI, AP, and ML directions, respectively. Tumor and diaphragm motions had high concordance when the distance between the tumor and tracked diaphragm area was small. Conclusions: This study showed that liver tumor motion had good correlation with diaphragm motion in the SI and AP directions, indicating diaphragm motion in the SI and AP directions could potentially be used as a reliable surrogate for liver tumor motion.

  15. Compressed-domain reverse play of MPEG video streams

    NASA Astrophysics Data System (ADS)

    Wee, Susie J.; Vasudev, Bhaskaran

    1999-01-01

    We present several compressed-domain methods for reverse- play transcoding of MPEG video streams. A reverse-play transcoder takes any original MPEG IPB bitstream as input and creates an output MPEG IPB bitstream which, when decoded by a generic MPEG decoder, displays the original video games in reverse order. A baseline spatial-domain method requires decoding the MPEG bitstream, storing and reordering the decoded video frames, and re-encoding the reordered video. The proposed compressed-domain transcoding methods achieve an order of magnitude reduction in computational complexity over the baseline spatial-domain approach. Much of the savings are achieved by using the forward motion vector fields available in the forward-play MPEG bitstream to efficiently generate the reverse motion vector fields used in the reverse-play MPEG bitstream. Furthermore, the storage requirements of the compressed-domain methods are reduced and the resulting image quality is within 0.6 dB of the baseline spatial-domain approach for a difficult highly detailed computer-generated video sequence. For more typical video sequences, the resulting image quality is even closer to the baseline spatial-domain approach.

  16. Real-time WAMI streaming target tracking in fog

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Blasch, Erik; Chen, Ning; Deng, Anna; Ling, Haibin; Chen, Genshe

    2016-05-01

    Real-time information fusion based on WAMI (Wide-Area Motion Imagery), FMV (Full Motion Video), and Text data is highly desired for many mission critical emergency or security applications. Cloud Computing has been considered promising to achieve big data integration from multi-modal sources. In many mission critical tasks, however, powerful Cloud technology cannot satisfy the tight latency tolerance as the servers are allocated far from the sensing platform, actually there is no guaranteed connection in the emergency situations. Therefore, data processing, information fusion, and decision making are required to be executed on-site (i.e., near the data collection). Fog Computing, a recently proposed extension and complement for Cloud Computing, enables computing on-site without outsourcing jobs to a remote Cloud. In this work, we have investigated the feasibility of processing streaming WAMI in the Fog for real-time, online, uninterrupted target tracking. Using a single target tracking algorithm, we studied the performance of a Fog Computing prototype. The experimental results are very encouraging that validated the effectiveness of our Fog approach to achieve real-time frame rates.

  17. Streaming Seismograms into Earth-Science Classrooms

    NASA Astrophysics Data System (ADS)

    Ammon, C. J.

    2011-12-01

    background motions, interesting and formulate good questions related to the signal details. A few minutes at the beginning of class reviewing the activity between classes and a few minutes when an earthquake occurs provide valuable discussion points related to earthquake science and seismic-wave propagation. Other tools discussed are related to global earthquake geography, with self-updating global maps of earthquakes (Epicentral, a MacOS and iOS application). When a signal first shows up on the EMMA seismogram display, students can invest a few minutes estimating the event's general location (and checking the signal character - relative arrival times, dispersion, etc). When a location is posted by an appropriate authority (e.g. the U. S. Geological Survey) the student's estimates can be checked and discussed. Additionally, Epicentral for MacOS presents a self-updated Twitter stream that can light up substantially when a felt earthquake occurs. Although the language of many of the tweeters can be colorful, the results are interesting and instant. The inclusion of these tools takes some time away from traditional lectures, but helps produce a dynamic, thought-provoking classroom experience.

  18. The Measurement of Visual Motion.

    DTIC Science & Technology

    1982-12-01

    rotates, translates and deforms over time, to yield the dotted curve C2 . The mapping of points from C1 to C2 is much less clear (consider, for example... deforming curve motion; different choices for the velocity field may yield different three-dimensional structures. The computation of a unique velocity...the velocity field, which will allow us to analyze the projected motion of three-dimensional objects 13 L _ allowed to move freely in space, and deform

  19. Tilts in strong ground motion

    USGS Publications Warehouse

    Graizer, V.

    2006-01-01

    Most instruments used in seismological practice to record ground motion are pendulum seismographs, velocigraphs, or accelerographs. In most cases it is assumed that seismic instruments are only sensitive to the translational motion of the instrument's base. In this study the full equation of pendulum motion, including the inputs of rotations and tilts, is considered. It is shown that tilting the accelerograph's base can severely impact its response to the ground motion. The method of tilt evaluation using uncorrected strong-motion accelerograms was first suggested by Graizer (1989), and later tested in several laboratory experiments with different strong-motion instruments. The method is based on the difference in the tilt sensitivity of the horizontal and vertical pendulums. The method was applied to many of the strongest records of the Mw 6.7 Northridge earthquake of 1994. Examples are shown when relatively large tilts of up to a few degrees occurred during strong earthquake ground motion. Residual tilt extracted from the strong-motion record at the Pacoima Dam-Upper Left Abutment reached 3.1?? in N45??E direction, and was a result of local earthquake-induced tilting due to high-amplitude shaking. This value is in agreement with the residual tilt measured by using electronic level a few days after the earthquake. The method was applied to the building records from the Northridge earthquake. According to the estimates, residual tilt reached 2.6?? on the ground floor of the 12-story Hotel in Ventura. Processing of most of the strongest records of the Northridge earthquake shows that tilts, if happened, were within the error of the method, or less than about 0.5??.

  20. Origin and evolution of recent Leonid meteor showers. [perturbed motion of meteor stream

    NASA Technical Reports Server (NTRS)

    Mcintosh, B. A.

    1973-01-01

    The four most prominent returns of the Leonid shower in the past decade fall into two broad classes. The 1966 and 1969 showers were of short duration, had a high proportion of small particles, and occured with the longest apparent delay after the perihelion passage of the parent comet Temple-Tuttle. By contrast, the 1961 and 1965 returns were of long duration, and had more large particles. The 1961 return preceded the comet. There are three major influences on particle orbits: ejection velocity, radiation pressure, and close encounters with planets. The observations are explainable in a qualitative way on the basis of the first two. But some speculation concerning the results of planetary perturbations are invoked.

  1. Motion of Particles in a Gas Stream in the Presence of Tangential and Axial Blowing

    NASA Astrophysics Data System (ADS)

    Teplitskii, Yu. S.; Pitsukha, E. A.; Prokopovich, O. V.

    2016-03-01

    Radial distributions of the velocity components of particles in a vertical vortex chamber in the presence of axial (bottom) blowing under conditions of quasi-solid rotation are considered, and the dependence of the particle rotation frequency on the Stokes number and the fraction of bottom blowing has been established.

  2. Globular Cluster Streams as Galactic High-Precision Scales - The Poster Child Palomar 5

    NASA Astrophysics Data System (ADS)

    Kupper, Andreas Hans Wilhelm; Balbinot, Eduardo; Bonaca, Ana; Johnston, Kathryn V.; Hogg, David W.; Kroupa, Pavel; Santiago, Basilio

    2015-01-01

    We model the tidal stream of the Milky Way globular cluster Palomar 5 (Pal 5), and show that the unique geometry of the problem yields powerful constraints on the model parameters characterizing the Local Standard of Rest (LSR), the Milky Way and Pal 5 itself. Using only SDSS data and a few radial velocities from the literature, we find that the distance of the Sun from the Galactic Center is 8.30+/-0.25 kpc, and the LSR transverse velocity is 242+/-16 km/s. Assuming that the dark halo of the Galaxy follows a NFW density profile, we fit it with a virial mass of (1.6+/-0.4) 1012Msun, a virial radius of 195+/-19 kpc, and hence a rather low concentration of 5+/-2. Moreover, we find it with a flattening of qz = 0.95(+0.16)(-0.12) to be essentially spherical - at least within the inner 25 kpc, which are effectively probed by Pal 5. We also determine Pal 5's mass, distance and proper motions independently from other methods, which enables us to perform vital cross-checks for these methods. We conclude that finding more globular cluster streams is essential for mapping out the structure of the halo of our Galaxy to high precision. Finally, we point out that all our best-fit models yield similar substructure patterns as the ones observed in the Pal 5 stream within about 5 kpc of the cluster. The origin of these substructures is epicylic motion of stars along the stream. Such epicylic substructures have to be taken into account when searching tidal streams for signs of past encounters with dark-matter subhalos

  3. Evaluating the reliability of the stream tracer approach to characterize stream-subsurface water exchange

    USGS Publications Warehouse

    Harvey, J.W.; Wagner, B.J.; Bencala, K.E.

    1996-01-01

    Stream water was locally recharged into shallow groundwater flow paths that returned to the stream (hyporheic exchange) in St. Kevin Gulch, a Rocky Mountain stream in Colorado contaminated by acid mine drainage. Two approaches were used to characterize hyporheic exchange: sub- reach-scale measurement of hydraulic heads and hydraulic conductivity to compute streambed fluxes (hydrometric approach) and reachscale modeling of in- stream solute tracer injections to determine characteristic length and timescales of exchange with storage zones (stream tracer approach). Subsurface data were the standard of comparison used to evaluate the reliability of the stream tracer approach to characterize hyporheic exchange. The reach-averaged hyporheic exchange flux (1.5 mL s-1 m-1), determined by hydrometric methods, was largest when stream base flow was low (10 L s-1); hyporheic exchange persisted when base flow was 10- fold higher, decreasing by approximately 30%. Reliability of the stream tracer approach to detect hyporheic exchange was assessed using first- order uncertainty analysis that considered model parameter sensitivity. The stream tracer approach did not reliably characterize hyporheic exchange at high base flow: the model was apparently more sensitive to exchange with surface water storage zones than with the hyporheic zone. At low base flow the stream tracer approach reliably characterized exchange between the stream and gravel streambed (timescale of hours) but was relatively insensitive to slower exchange with deeper alluvium (timescale of tens of hours) that was detected by subsurface measurements. The stream tracer approach was therefore not equally sensitive to all timescales of hyporheic exchange. We conclude that while the stream tracer approach is an efficient means to characterize surface-subsurface exchange, future studies will need to more routinely consider decreasing sensitivities of tracer methods at higher base flow and a potential bias toward

  4. Slow motion increases perceived intent

    PubMed Central

    Caruso, Eugene M.; Burns, Zachary C.; Converse, Benjamin A.

    2016-01-01

    To determine the appropriate punishment for a harmful action, people must often make inferences about the transgressor’s intent. In courtrooms and popular media, such inferences increasingly rely on video evidence, which is often played in “slow motion.” Four experiments (n = 1,610) involving real surveillance footage from a murder or broadcast replays of violent contact in professional football demonstrate that viewing an action in slow motion, compared with regular speed, can cause viewers to perceive an action as more intentional. This slow motion intentionality bias occurred, in part, because slow motion video caused participants to feel like the actor had more time to act, even when they knew how much clock time had actually elapsed. Four additional experiments (n = 2,737) reveal that allowing viewers to see both regular speed and slow motion replay mitigates the bias, but does not eliminate it. We conclude that an empirical understanding of the effect of slow motion on mental state attribution should inform the life-or-death decisions that are currently based on tacit assumptions about the objectivity of human perception. PMID:27482091

  5. Ecoregions and stream morphology in eastern Oklahoma

    USGS Publications Warehouse

    Splinter, D.K.; Dauwalter, D.C.; Marston, R.A.; Fisher, W.L.

    2010-01-01

    Broad-scale variables (i.e., geology, topography, climate, land use, vegetation, and soils) influence channel morphology. How and to what extent the longitudinal pattern of channel morphology is influenced by broad-scale variables is important to fluvial geomorphologists and stream ecologists. In the last couple of decades, there has been an increase in the amount of interdisciplinary research between fluvial geomorphologists and stream ecologists. In a historical context, fluvial geomorphologists are more apt to use physiographic regions to distinguish broad-scale variables, while stream ecologists are more apt to use the concept of an ecosystem to address the broad-scale variables that influence stream habitat. For this reason, we designed a study using ecoregions, which uses physical and biological variables to understand how landscapes influence channel processes. Ecoregions are delineated by similarities in geology, climate, soils, land use, and potential natural vegetation. In the fluvial system, stream form and function are dictated by processes observed throughout the fluvial hierarchy. Recognizing that stream form and function should differ by ecoregion, a study was designed to evaluate how the characteristics of stream channels differed longitudinally among three ecoregions in eastern Oklahoma, USA: Boston Mountains, Ozark Highlands, and Ouachita Mountains. Channel morphology of 149 stream reaches was surveyed in 1st- through 4th-order streams, and effects of drainage area and ecoregion on channel morphology was evaluated using multiple regressions. Differences existed (?????0.05) among ecoregions for particle size, bankfull width, and width/depth ratio. No differences existed among ecoregions for gradient or sinuosity. Particle size was smallest in the Ozark Highlands and largest in the Ouachita Mountains. Bankfull width was larger in the Ozark Highlands than in the Boston Mountains and Ouachita Mountains in larger streams. Width/depth ratios of the

  6. Self-Motion and the Shaping of Sensory Signals

    PubMed Central

    Jenks, Robert A.; Vaziri, Ashkan; Boloori, Ali-Reza

    2010-01-01

    Sensory systems must form stable representations of the external environment in the presence of self-induced variations in sensory signals. It is also possible that the variations themselves may provide useful information about self-motion relative to the external environment. Rats have been shown to be capable of fine texture discrimination and object localization based on palpation by facial vibrissae, or whiskers, alone. During behavior, the facial vibrissae brush against objects and undergo deflection patterns that are influenced both by the surface features of the objects and by the animal's own motion. The extent to which behavioral variability shapes the sensory inputs to this pathway is unknown. Using high-resolution, high-speed videography of unconstrained rats running on a linear track, we measured several behavioral variables including running speed, distance to the track wall, and head angle, as well as the proximal vibrissa deflections while the distal portions of the vibrissae were in contact with periodic gratings. The measured deflections, which serve as the sensory input to this pathway, were strongly modulated both by the properties of the gratings and the trial-to-trial variations in head-motion and locomotion. Using presumed internal knowledge of locomotion and head-rotation, gratings were classified using short-duration trials (<150 ms) from high-frequency vibrissa motion, and the continuous trajectory of the animal's own motion through the track was decoded from the low frequency content. Together, these results suggest that rats have simultaneous access to low- and high-frequency information about their environment, which has been shown to be parsed into different processing streams that are likely important for accurate object localization and texture coding. PMID:20164407

  7. Method of removing contaminant from a feedstock stream

    SciTech Connect

    Holland, E. O.; Johnson, M. M.

    1981-05-26

    Contaminants such as petroleum sulfonates, anticorrosion amines, and silicone oils are removed from a contaminated feedstock stream by contacting said feedstock stream with an adsorbent comprising bauxite. In a further aspect, a thus purified petroleum feedstock stream is hydrodesulfurized.

  8. Method of removing contaminant from a feedstock stream

    SciTech Connect

    Holland, E.O.; Johnson, M.M.

    1982-08-10

    Contaminants such as petroleum sulfonates, anticorrosion amines, and silicone oils are removed from a contaminated feedstock stream by contacting said feedstock stream with an adsorbent comprising bauxite. In a further aspect, a thus purified petroleum feedstock stream is hydrodesulfurized.

  9. Martian Landscapes in Motion

    NASA Astrophysics Data System (ADS)

    Mattson, Sarah; McEwen, Alfred; Kirk, Randolph; Howington-Kraus, Elpitha; Chojnacki, Matthew; Runyon, Kirby; Cremonese, Gabriele; Re, Cristina

    2014-05-01

    RISE orthorectified image sequences makes it possible to conduct accurate change detection studies of active processes on Mars. Some examples of studies of active landscapes on Mars using HiRISE DTMs and orthoimage sequences include: dune and ripple motion (Bridges et al., 2012, Nature), recurring slope lineae (RSL) (McEwen et al., 2011, Science; McEwen et al., 2013, Nature Geoscience), gully activity (Dundas et al., 2012, Icarus), and polar processes (Hansen et al., 2011, Science; Portyankina et al. 2013, Icarus,). These studies encompass images from multiple Mars years and seasons. Sequences of orthoimages make it possible to generate animated gifs or movies to visualize temporal changes (http://www.uahirise.org/sim/). They can also be brought into geospatial software to quantitatively map and record changes. The ability to monitor the surface of Mars at high spatial resolution with frequent repeat images has opened up our insight into seasonal and interannual changes, further increasing our understanding of Mars as an active planet.

  10. Kinematical Clues to the Origin of the Virgo Stellar Stream

    NASA Astrophysics Data System (ADS)

    Yam, William; Carlin, J. L.; Casetti-Dinescu, D. I.; Willett, B. A.; Newberg, H.; Majewski, S. R.; Girard, T. M.

    2012-01-01

    Milky Way stellar substructure has been detected in the Virgo constellation (the so-called Virgo Stellar Stream, or VSS; and the possibly associated Virgo Overdensity) using a variety of different stellar tracers over a large (perhaps 100-1000 square degrees) area of sky, but the nature of the overdensities has yet to be determined. Fortuitously, one of Kapteyn's Selected Areas (SAs) making up our deep proper motion survey (Casetti-Dinescu et al. 2006) intersects this structure. Our data in this field, denoted SA 103, span 40x40 arcminutes centered at (RA, Dec) = (178.8, -0.6). We supplemented our proper motions with multifiber spectroscopy. VSS members are selected via kinematics (radial velocities and proper motions), as well as position on the CMD. Theoretical isochrones were fitted to the identified members in the CMD to obtain distance. We find 14 candidates with properties consistent with membership in the VSS (based in part on comparison to previous detections), and use the mean 3-D kinematics of these members to derive an orbit for the VSS debris. We show that Virgo debris is near the pericenter of a high-eccentricity, plunging orbit similar to that found by Casetti-Dinescu et al. (2009) based on one VSS RR-Lyrae star. We explore possible progenitors for the VSS by integrating an orbit with the measured kinematics and comparing this to known Milky Way satellites and stellar substructures. At least three structures (a dwarf galaxy, globular cluster, and at least one diffuse stellar overdensity) are identified whose properties suggest that they may be related to the VSS. An n-body simulation of a Sagittarius-sized dwarf galaxy on our derived orbit produces a remnant with similar properties to the extant VSS detections, supporting the idea that the VSS is the remains of a tidally disrupted dwarf galaxy. Supported by NSF grants AST 09-37523, AST 11-15146, AST 10-09670.

  11. Ecological health in the Nation's streams

    USGS Publications Warehouse

    Carlisle, Daren M.; Woodside, Michael D.

    2013-01-01

    Aquatic biological communities, which are collections of organisms, are a direct measure of stream health because they indicate the ability of a stream to support life. This fact sheet highlights selected findings of a national assessment of stream health by the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). The assessment was unique in that it integrated the condition of three biological communities—algae, macroinvertebrates, and fish—as well as measures of streamflow modification, pesticides, nutrients, and other factors. At least one biological community was altered at 83 percent of assessed streams, and the occurrence of altered communities was highest in urban streams. Streamflows were modified at 86 percent of assessed streams, and increasing severity of streamflow modification was associated with increased occurrence of altered biological communities. Agricultural and urban land use in watersheds may contribute pesticides and nutrients to stream waters, and increasing concentrations of these chemicals were associated with increased occurrence of altered biological communities.

  12. Charting the trajectory of the ATLAS stream

    NASA Astrophysics Data System (ADS)

    de Boer, Thomas; Belokurov, Vasily; Koposov, Sergey; Irwin, Mike; Erkal, Denis

    2014-08-01

    Stellar streams provide dramatic confirmation that large systems accrete smaller systems, in the context of a hierarchical merging cosmology, and therefore contain important clues about the formation mechanism of the Galactic halo. By studying the detailed properties of streams we can determine how stars are stripped from their hosts due to the Galactic tidal field and how the formation of the Galactic halo may have proceeded. Here we propose to trace the full visible extent of the recently discovered ATLAS stream using deep, wide-field photometry, to determine its path across the sky in 3 dimensions. By utilising the very wide-field capabilities of DECam, we will determine the deep, MW decontaminated CMD in a 30 degree long portion of the stream, allowing us to determine the distance, density profile and stellar population makeup of the stream. The position and density on the sky of kinematically cold structures like the ATLAS stream provides powerful, unbiased constraints on the distribution of dark matter in the Galaxy. Furthermore, deep photometry of the stellar content of the stream will tell us what type of system was the likely progenitor: globular cluster, ultra-faint dwarf or dSph galaxy.

  13. Acoustic streaming of a sharp edge.

    PubMed

    Ovchinnikov, Mikhail; Zhou, Jianbo; Yalamanchili, Satish

    2014-07-01

    Anomalous acoustic streaming is observed emanating from sharp edges of solid bodies that are vibrating in fluids. The streaming velocities can be orders of magnitude higher than expected from the Rayleigh streaming at similar amplitudes of vibration. Acoustic velocity of fluid relative to a solid body diverges at a sharp edge, giving rise to a localized time-independent body force acting on the fluid. This force results in a formation of a localized jet. Two-dimensional numerical simulations are performed to predict acoustic streaming for low amplitude vibration using two methods: (1) Steady-state solution utilizing perturbation theory and (2) direct transient solution of the Navier-Stokes equations. Both analyses agree with each other and correctly predict the streaming of a sharp-edged vibrating blade measured experimentally. The origin of the streaming can be attributed to the centrifugal force of the acoustic fluid flow around a sharp edge. The dependence of this acoustic streaming on frequency and velocity is examined using dimensional analysis. The dependence law is devised and confirmed by numerical simulations.

  14. The Fornax-Leo-Sculptor stream revisited

    NASA Astrophysics Data System (ADS)

    Majewski, Steven R.

    1994-08-01

    Lynden-Bell first demonstrated that the satellites of the Milky Way appear situated along two great 'streams' in the sky: the 'Magellanic stream' and the 'Fornax-Leo-Sculptor (FLS) stream.' Further exploration of the three-dimensional distribution of Galactic satellites reveals that the recently discovered Sextans and Phoenix dwarf spheroidal galaxies also lie near the plane defined by the FLS galaxies, and therefore strengthens the evidence in favor of the FLS stream. Moreover, a specific group of globular clusters -- those exhibiting the reddest horizontal branches (HBs) among those identified as 'young halo' by Zinn -- appear to populate the FLS stream. As previously demonstrated by Zinn, the spatial distribution of old halo globulars appears to be flattened toward the Galactic plane, and therefore the old halo clusters are typically anti-correlated to the nearly orthogonal FLS stream. A scenario is postulated wherein the Galactic satellites of the FLS stream and the red HB, young halo globular clusters share a common origin in the accretion of a formerly larger, parent satellite galaxy or Searle & Zinn 'fragment.'

  15. The Fornax-Leo-Sculptor stream revisited

    NASA Technical Reports Server (NTRS)

    Majewski, Steven R.

    1994-01-01

    Lynden-Bell first demonstrated that the satellites of the Milky Way appear situated along two great 'streams' in the sky: the 'Magellanic stream' and the 'Fornax-Leo-Sculptor (FLS) stream.' Further exploration of the three-dimensional distribution of Galactic satellites reveals that the recently discovered Sextans and Phoenix dwarf spheroidal galaxies also lie near the plane defined by the FLS galaxies, and therefore strengthens the evidence in favor of the FLS stream. Moreover, a specific group of globular clusters -- those exhibiting the reddest horizontal branches (HBs) among those identified as 'young halo' by Zinn -- appear to populate the FLS stream. As previously demonstrated by Zinn, the spatial distribution of old halo globulars appears to be flattened toward the Galactic plane, and therefore the old halo clusters are typically anti-correlated to the nearly orthogonal FLS stream. A scenario is postulated wherein the Galactic satellites of the FLS stream and the red HB, young halo globular clusters share a common origin in the accretion of a formerly larger, parent satellite galaxy or Searle & Zinn 'fragment.'

  16. Fast algorithm for automatically computing Strahler stream order

    USGS Publications Warehouse

    Lanfear, Kenneth J.

    1990-01-01

    An efficient algorithm was developed to determine Strahler stream order for segments of stream networks represented in a Geographic Information System (GIS). The algorithm correctly assigns Strahler stream order in topologically complex situations such as braided streams and multiple drainage outlets. Execution time varies nearly linearly with the number of stream segments in the network. This technique is expected to be particularly useful for studying the topology of dense stream networks derived from digital elevation model data.

  17. Acoustofluidics 14: Applications of acoustic streaming in microfluidic devices.

    PubMed

    Wiklund, Martin; Green, Roy; Ohlin, Mathias

    2012-07-21

    In part 14 of the tutorial series "Acoustofluidics--exploiting ultrasonic standing wave forces and acoustic streaming in microfluidic systems for cell and particle manipulation", we provide a qualitative description of acoustic streaming and review its applications in lab-on-a-chip devices. The paper covers boundary layer driven streaming, including Schlichting and Rayleigh streaming, Eckart streaming in the bulk fluid, cavitation microstreaming and surface-acoustic-wave-driven streaming.

  18. Traveltime and longitudinal dispersion in Illinois streams

    USGS Publications Warehouse

    Graf, Julia B.

    1986-01-01

    Twenty-seven measurements of traveltime and longitudinal dispersion in 10 Illinois streams made from 1975 to 1982 provide data needed for estimating traveltime of peak concentration of a conservative solute, traveltime of the leading edge of a solute cloud, peak concentration resulting from injection of a given quantity of solute, and passage time of solute past a given point on a stream. These four variables can be estimated graphically for each stream from distance of travel and either discharge at the downstream end of the reach or flow-duration frequency. From equations developed from field measurements, the traveltime and dispersion characteristics also can be estimated for other unregulated streams in Illinois that have drainage areas less than about 1,500 square miles. For unmeasured streams, traveltime of peak concentration and of the leading edge of the cloud are related to discharge at the downstream end of the reach and to distance of travel. For both measured and unmeasured streams, peak concentration and passage time are best estimated from the relation of each to traveltime. In measured streams, dispersion efficiency is greater than that predicted by Fickian diffusion theory. The rate of decrease in peak concentration with traveltime is about equal to the rate of increase in passage time. Average velocity in a stream reach, given by the velocity of the center of solute mass in that reach, can be estimated from an equation developed from measured values. The equation relates average reach velocity to discharge at the downstream end of the reach. Average reach velocities computed for 9 of the 10 streams from available equations that are based on hydraulic-geometry relations are high relative to measured values. The estimating equation developed from measured velocities provides estimates of average reach velocity that are closer to measured velocities than are those computed using equations developed from hydraulic-geometry relations.

  19. Mercury bioaccumulation in a stream network.

    PubMed

    Tsui, Martin Tsz Ki; Finlay, Jacques C; Nater, Edward A

    2009-09-15

    Mercury (Hg) contamination is common in stream and river ecosystems, but factors mediating Hg cycling in the flowing waters are much less understood than inthe lakes and wetlands. In this study, we examined the spatial patterns of methylmercury (MeHg) concentrations in the dominant groups of aquatic insect larvae across a network of streams (drainage area ranging from 0.5 to 150 km2) in northern California during summer baseflow conditions. We found that, with the exception of water striders, all invertebrate groups showed significant (p < 0.05) increases in MeHg concentrations with drainage area. The largest stream in our study watershed, the South Fork Eel River, had the highest aqueous MeHg concentration (unfiltered: 0.13-0.17 ng L(-1)) while most of the upstream tributaries had aqueous MeHg concentrations close to or below the established detection limits (0.02 ng L(-1)). A filamentous alga abundant in South Fork Eel River (Cladophora glomerata) had an exceptionally high fraction of total-Hg as MeHg (i.e., %MeHg from 50-100%). Since other potential hotspots of in-stream Hg methylation (e.g., surface sediment and deep pools) had %MeHg lower than or similar to surface water (approximately 14%), we hypothesize that Cladophora and possibly other autotrophs may serve as hotspots of in-stream MeHg production in this bedrock-dominated stream. Recent studies in other regions concluded that wetland abundance in the watershed is the predominant factor in governing Hg concentrations of stream biota. However, our results show that in the absence of wetlands, substantial spatial variation of Hg bioaccumulation can arise in stream networks due to the influence of in-stream processes.

  20. The Role of Ice Streams in Deglaciation

    NASA Astrophysics Data System (ADS)

    Robel, A.; Schoof, C.; Tziperman, E.

    2014-12-01

    Ice streams are regions of fast flow within ice sheets that can exhibit variability on time scales ranging from years to millennia. Observations and model reconstructions indicate that ice streams likely played a major role in the most recent deglaciation of the Laurentide Ice Sheet. The variability of these ice streams may have dictated the spatiotemporal progression of deglaciation, as some ice sheet domes may have been more sensitive to dynamic changes in ice stream activity. We analyze the behavior of both idealized and realistic ice sheet configurations to determine the role of ice streams in setting ice sheet steady states and the spatiotemporal sequence of deglacial transitions. We also examine the way in which climate feedbacks could have amplified the response of ice streams to Milankovitch forcing, thereby initiating ice sheet collapse. We use the Parallel Ice Sheet Model (PISM), by itself and coupled to an energy balance atmospheric model. The presence of ice streams dramatically alters steady-state ice sheet configurations, allowing for the existence of thin, widely extended margins. There is a marked transition from binge-purge-like ice stream variability (that is believed to have occurred as part of Heinrich events during the last glacial period) to steady ice stream flow as climate (temperature, precipitation) is varied over a range corresponding to glacial variability. This qualitative transition in ice sheet dynamics amplifies small changes in external forcing (e.g. Milankovitch cycles) sufficiently to activate strong climate feedbacks. We discuss how the reorganization of ice sheet configuration, through changes in ice sheet extent and elevation, may favor certain climate feedbacks (e.g. ice-albedo and lapse rate feedbacks). We also relate these analyses to observations of Laurentide deglaciation and discuss implications for the future of the Greenland and Antarctic Ice Sheets.

  1. Resonance and streaming of armored microbubbles

    NASA Astrophysics Data System (ADS)

    Spelman, Tamsin; Bertin, Nicolas; Stephen, Olivier; Marmottant, Philippe; Lauga, Eric

    2015-11-01

    A new experimental technique involves building a hollow capsule which partially encompasses a microbubble, creating an ``armored microbubble'' with long lifespan. Under acoustic actuation, such bubble produces net streaming flows. In order to theoretically model the induced flow, we first extend classical models of free bubbles to describe the streaming flow around a spherical body for any known axisymmetric shape oscillation. A potential flow model is then employed to determine the resonance modes of the armored microbubble. We finally use a more detailed viscous model to calculate the surface shape oscillations at the experimental driving frequency, and from this we predict the generated streaming flows.

  2. Methods of separating particulate residue streams

    DOEpatents

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, J. Richard

    2011-04-05

    A particulate residue separator and a method for separating a particulate residue stream may include an air plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams that are formed by the harvesting device and that travel, at least in part, along the air plenum and in a direction of the second, exhaust end; and a baffle assembly that is located in partially occluding relation relative to the air plenum and that substantially separates the first and second particulate residue air streams.

  3. Imaging of NGC 5907's stellar stream

    NASA Astrophysics Data System (ADS)

    Laine, Seppo; Grillmair, Carl J.; Martínez-Delgado, David; Romanowsky, Aaron J.; Capak, Peter L.; Arendt, Richard G.; Ashby, Matthew L. N.; Davies, James E.; Majewski, Steven R.; Gabany, R. Jay

    2016-08-01

    We have obtained deep g, r, and i-band Subaru and ultra-deep 3.6 μm IRAC images of parts of the multiply-wrapped stellar stream around the nearby edge-on galaxy NGC 5907. We have fitted the surface brightness measurements of the stream with FSPS stellar population synthesis models to derive the metallicity and age of the brightest parts of the stream. The resulting relatively high metallicity ([Fe/H] = -0.3) is consistent with a major merger scenario but a satellite accretion event cannot be ruled out.

  4. Events and Trends in Text Streams

    SciTech Connect

    Engel, David W.; Whitney, Paul D.; Cramer, Nicholas O.

    2010-03-04

    "Text streams--collections of documents or messages that are generated and observed over time--are ubiquitous. Our research and development are targeted at developing algorithms to find and characterize changes in topic within text streams. To date, this research has demonstrated the ability to detect and describe 1) short duration, atypical events and 2) the emergence of longer-term shifts in topical content. This technology has been applied to predefined temporally ordered document collections but is also suitable for application to near-real-time textual data streams."

  5. Benchmarking real-time HEVC streaming

    NASA Astrophysics Data System (ADS)

    Nightingale, James; Wang, Qi; Grecos, Christos

    2012-06-01

    Work towards the standardisation of High Efficiency Video Coding (HEVC), the next generation video coding scheme, is currently gaining pace. HEVC offers the prospect of a 50% improvement in compression over the current H.264 Advanced Video Coding standard (H.264/AVC). Thus far, work on HEVC has concentrated on improvements to the coding efficiency and has not yet addressed transmission in networks other than to mandate byte stream compliance with Annex B of H.264/AVC. For practical networked HEVC applications a number of essential building blocks have yet to be defined. In this work, we design and prototype a real-time HEVC streaming system and empirically evaluate its performance, in particular we consider the robustness of the current Test Model under Consideration (TMuC HM4.0) for HEVC to packet loss caused by a reduction in available bandwidth both in terms of decoder resilience and degradation in perceptual video quality. A NAL unit packetisation and streaming framework for HEVC encoded video streams is designed, implemented and empirically tested in a number of streaming environments including wired, wireless, single path and multiple path network scenarios. As a first step the HEVC decoder's error resilience is tested under a comprehensive set of packet loss conditions and a simple error concealment method for HEVC is implemented. Similarly to H.264 encoded streams, the size and distribution of NAL units within an HEVC stream and the nature of the NAL unit dependencies influences the packetisation and streaming strategies which may be employed for such streams. The relationships between HEVC encoding mode and the quality of the received video are shown under a wide range of bandwidth constraints. HEVC streaming is evaluated in both single and multipath network configuration scenarios. Through the use of extensive experimentation, we establish a comprehensive set of benchmarks for HEVC streaming in loss prone network environments. We show the visual quality

  6. Pose and motion from contact

    SciTech Connect

    Jia, Y.B.; Erdmann, M.

    1999-05-01

    In the absence of vision, grasping an object often relies on tactile feedback from the fingertips. As the finger pushes the object, the fingertip can feel the contact point move. If the object is known in advance, from this motion the finger may infer the location of the contact point on the object, and thereby, the object pose. This paper primarily investigates the problem of determining the pose (orientation and position) and motion (velocity and angular velocity) of a planar object with known geometry from such contact motion generated by pushing. A dynamic analysis of pushing yields a nonlinear system that relates through contact the object pose and motion to the finger motion. The contact motion on the fingertip thus encodes certain information about the object pose. Nonlinear observability theory is employed to show that such information is sufficient for the finger to observe not only the pose, but also the motion of the object. Therefore, a sensing strategy can be realized as an observer of the nonlinear dynamic system. Two observers are subsequently introduced. The first observer, based on the work of Gautheir, Hammouri, and Othman (1992), has its gain determined by the solution of a Lyapunov-like equation; it can be activated at any time instant during a push. The second observer, based on Newton`s method, solves for the initial (motionless) object pose from three intermediate contact points during a push. Under the Coulomb-friction model, the paper deals with support friction in the plane and/or contact friction between the finger and the object. Extensive simulations have been done to demonstrate the feasibility of the two observers. Preliminary experiments (with an Adept robot) have also been conducted. A contact sensor has been implemented using strain gauges.

  7. Quantitative assessment of human motion using video motion analysis

    NASA Technical Reports Server (NTRS)

    Probe, John D.

    1990-01-01

    In the study of the dynamics and kinematics of the human body, a wide variety of technologies was developed. Photogrammetric techniques are well documented and are known to provide reliable positional data from recorded images. Often these techniques are used in conjunction with cinematography and videography for analysis of planar motion, and to a lesser degree three-dimensional motion. Cinematography has been the most widely used medium for movement analysis. Excessive operating costs and the lag time required for film development coupled with recent advances in video technology have allowed video based motion analysis systems to emerge as a cost effective method of collecting and analyzing human movement. The Anthropometric and Biomechanics Lab at Johnson Space Center utilizes the video based Ariel Performance Analysis System to develop data on shirt-sleeved and space-suited human performance in order to plan efficient on orbit intravehicular and extravehicular activities. The system is described.

  8. Digital Motion Imagery, Interoperability Challenges for Space Operations

    NASA Technical Reports Server (NTRS)

    Grubbs, Rodney

    2012-01-01

    With advances in available bandwidth from spacecraft and between terrestrial control centers, digital motion imagery and video is becoming more practical as a data gathering tool for science and engineering, as well as for sharing missions with the public. The digital motion imagery and video industry has done a good job of creating standards for compression, distribution, and physical interfaces. Compressed data streams can easily be transmitted or distributed over radio frequency, internet protocol, and other data networks. All of these standards, however, can make sharing video between spacecraft and terrestrial control centers a frustrating and complicated task when different standards and protocols are used by different agencies. This paper will explore the challenges presented by the abundance of motion imagery and video standards, interfaces and protocols with suggestions for common formats that could simplify interoperability between spacecraft and ground support systems. Real-world examples from the International Space Station will be examined. The paper will also discuss recent trends in the development of new video compression algorithms, as well likely expanded use of Delay (or Disruption) Tolerant Networking nodes.

  9. Embodied learning of a generative neural model for biological motion perception and inference

    PubMed Central

    Schrodt, Fabian; Layher, Georg; Neumann, Heiko; Butz, Martin V.

    2015-01-01

    Although an action observation network and mirror neurons for understanding the actions and intentions of others have been under deep, interdisciplinary consideration over recent years, it remains largely unknown how the brain manages to map visually perceived biological motion of others onto its own motor system. This paper shows how such a mapping may be established, even if the biologically motion is visually perceived from a new vantage point. We introduce a learning artificial neural network model and evaluate it on full body motion tracking recordings. The model implements an embodied, predictive inference approach. It first learns to correlate and segment multimodal sensory streams of own bodily motion. In doing so, it becomes able to anticipate motion progression, to complete missing modal information, and to self-generate learned motion sequences. When biological motion of another person is observed, this self-knowledge is utilized to recognize similar motion patterns and predict their progress. Due to the relative encodings, the model shows strong robustness in recognition despite observing rather large varieties of body morphology and posture dynamics. By additionally equipping the model with the capability to rotate its visual frame of reference, it is able to deduce the visual perspective onto the observed person, establishing full consistency to the embodied self-motion encodings by means of active inference. In further support of its neuro-cognitive plausibility, we also model typical bistable perceptions when crucial depth information is missing. In sum, the introduced neural model proposes a solution to the problem of how the human brain may establish correspondence between observed bodily motion and its own motor system, thus offering a mechanism that supports the development of mirror neurons. PMID:26217215

  10. Riparian and in-stream controls on nutrient concentrations and fluxes in a headwater forested stream

    NASA Astrophysics Data System (ADS)

    Bernal, S.; Lupon, A.; Ribot, M.; Sabater, F.; Martí, E.

    2015-03-01

    Headwater streams are recipients of water sources draining through terrestrial ecosystems. At the same time, stream biota can transform and retain nutrients dissolved in stream water. Yet studies considering simultaneously these two sources of variation in stream nutrient chemistry are rare. To fill this gap of knowledge, we analyzed stream water and riparian groundwater concentrations and fluxes as well as in-stream net uptake rates for nitrate (NO3-), ammonium (NH4+), and soluble reactive phosphorus (SRP) along a 3.7 km reach on an annual basis. Chloride concentrations (used as conservative tracer) indicated a strong hydrological connection at the riparian-stream interface. However, stream and riparian groundwater nutrient concentrations showed a moderate to null correlation, suggesting high in-stream biogeochemical processing. In-stream net nutrient uptake (Fsw) was highly variable across contiguous segments and over time, but its temporal variation was not related to the vegetative period of the riparian forest. For NH4+, the occurrence of Fsw > 0 μg N m-1 s-1 (gross uptake > release) was high along the reach, while for NO3-, the occurrence of Fsw < 0 μg N m-1 s-1 (gross uptake < release) increased along the reach. Within segments and dates, Fsw, whether negative or positive, accounted for a median of 6, 18, and 20% of the inputs of NO3-, NH4+, and SRP, respectively. Whole-reach mass balance calculations indicated that in-stream net uptake reduced stream NH4+ flux up to 90%, while the stream acted mostly as a source of NO3- and SRP. During the dormant period, concentrations decreased along the reach for NO3-, but increased for NH4+ and SRP. During the vegetative period, NH4+ decreased, SRP increased, and NO3- showed a U-shaped pattern along the reach. These longitudinal trends resulted from the combination of hydrological mixing with terrestrial inputs and in-stream nutrient processing. Therefore, the assessment of these two sources of variation in stream

  11. 29 CFR 1603.208 - Motions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... procedural matters, the administrative law judge may not grant a written motion prior to the expiration of the time for filing responses. The administrative law judge may deny a written motion without awaiting... filing of a motion does not stay the proceeding. (e) All motions and responses must comply with...

  12. 22 CFR 224.28 - Motions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Motions. 224.28 Section 224.28 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT IMPLEMENTATION OF THE PROGRAM FRAUD CIVIL REMEDIES ACT § 224.28 Motions. (a) Any application to the ALJ for an order or ruling shall be by motion. Motions...

  13. 10 CFR 13.28 - Motions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Motions. 13.28 Section 13.28 Energy NUCLEAR REGULATORY COMMISSION PROGRAM FRAUD CIVIL REMEDIES § 13.28 Motions. (a) Any application to the ALJ for an order or ruling shall be by motion. Motions shall state the relief sought, the authority relied upon, and...

  14. A dynamically reconfigurable data stream processing system

    SciTech Connect

    Nogiec, J.M.; Trombly-Freytag, K.; /Fermilab

    2004-11-01

    This paper describes a component-based framework for data stream processing that allows for configuration, tailoring, and runtime system reconfiguration. The system's architecture is based on a pipes and filters pattern, where data is passed through routes between components. A network of pipes and filters can be dynamically reconfigured in response to a preplanned sequence of processing steps, operator intervention, or a change in one or more data streams. This framework provides several mechanisms supporting dynamic reconfiguration and can be used to build static data stream processing applications such as monitoring or data acquisition systems, as well as self-adjusting systems that can adapt their processing algorithm, presentation layer, or data persistency layer in response to changes in input data streams.

  15. Reactive solute transport in acidic streams

    USGS Publications Warehouse

    Broshears, R.E.

    1996-01-01

    Spatial and temporal profiles of Ph and concentrations of toxic metals in streams affected by acid mine drainage are the result of the interplay of physical and biogeochemical processes. This paper describes a reactive solute transport model that provides a physically and thermodynamically quantitative interpretation of these profiles. The model combines a transport module that includes advection-dispersion and transient storage with a geochemical speciation module based on MINTEQA2. Input to the model includes stream hydrologic properties derived from tracer-dilution experiments, headwater and lateral inflow concentrations analyzed in field samples, and a thermodynamic database. Simulations reproduced the general features of steady-state patterns of observed pH and concentrations of aluminum and sulfate in St. Kevin Gulch, an acid mine drainage stream near Leadville, Colorado. These patterns were altered temporarily by injection of sodium carbonate into the stream. A transient simulation reproduced the observed effects of the base injection.

  16. Noise Prediction Module for Offset Stream Nozzles

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda S.

    2011-01-01

    A Modern Design of Experiments (MDOE) analysis of data acquired for an offset stream technology was presented. The data acquisition and concept development were funded under a Supersonics NRA NNX07AC62A awarded to Dimitri Papamoschou at University of California, Irvine. The technology involved the introduction of airfoils in the fan stream of a bypass ratio (BPR) two nozzle system operated at transonic exhaust speeds. The vanes deflected the fan stream relative to the core stream and resulted in reduced sideline noise for polar angles in the peak jet noise direction. Noise prediction models were developed for a range of vane configurations. The models interface with an existing ANOPP module and can be used or future system level studies.

  17. Flood-frequency characteristics of Wisconsin streams

    USGS Publications Warehouse

    Walker, John F.; Krug, William R.

    2003-01-01

    Flood-frequency characteristics for 312 gaged sites on Wisconsin streams are presented for recurrence intervals of 2 to 100 years using flood-peak data collected through water year 2000. Equations of the relations between flood-frequency and drainage-basin characteristics were developed by multiple-regression analyses. Flood-frequency characteristics for ungaged sites on unregulated, rural streams can be estimated by use of these equations. The state was divided into five areas with similar physiographic characteristics. The most significant basin characteristics are drainage area, main-channel slope, soil permeability, storage, rainfall intensity, and forest cover. The standard error of prediction for the equation for the 100-year flood discharge ranges from 22 to 44 percent in the state. A graphical method for estimating flood-frequency characteristics of regulated streams was developed from the relation of discharge and drainage area. Graphs for the major regulated streams are presented.

  18. Water Stream "Loop-the-Loop"

    ERIC Educational Resources Information Center

    Jefimenko, Oleg

    1974-01-01

    Discusses the design of a modified loop-the-loop apparatus in which a water stream is used to illustrate centripetal forces and phenomena of high-velocity hydrodynamics. Included are some procedures of carrying out lecture demonstrations. (CC)

  19. A kinetic cross-field streaming instability

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Winske, D.; Papadopoulos, K.; Zhou, Y. M.; Tsai, S. T.; Guo, S. C.

    1983-01-01

    In a high-beta plasma the so-called modified-two-stream instability, which results from strongly magnetized electrons drifting relative to unmagnetized ions across a homogeneous magnetic field, is misnamed because the mode is highly kinetic, particularly when the relative streaming velocity exceeds the Alfven speed of the plasma. This kinetic cross-field streaming instability is investigated in detail, examining the effect of the electromagnetic terms and the stability boundaries in both low- and high-beta plasmas. An approximate dispersion relation showing the relation of this mode to the whistler is derived and solutions of it are compared with those obtained from the exact dispersion relation. The kinetic mode, unlike the usual modified-two-stream instability, is not stabilized by electromagnetic effects when the relative electron-ion drift speed exceeds the Alfven speed.

  20. Salt vulnerability assessment methodology for urban streams

    NASA Astrophysics Data System (ADS)

    Betts, A. R.; Gharabaghi, B.; McBean, E. A.

    2014-09-01

    De-icing agents such as road salts while used for winter road maintenance can cause negative effects on urban stream water quality and drinking water supplies. A new methodology using readily available spatial data to identify Salt Vulnerable Areas (SVAs) for urban streams is used to prioritize implementation of best management practices. The methodology calculates the probable chloride concentration statistics at specified points in the urban stream network and compares the results with known aquatic species exposure tolerance limits to characterize the vulnerability scores. The approach prioritizes implementation of best management practices to areas identified as vulnerable to road salt. The vulnerability assessment is performed on seven sites in four watersheds in the Greater Toronto Area and validated using the Hanlon Creek watershed in Guelph. The mean annual in-stream chloride concentration equation uses readily available spatial data - with province-wide coverage - that can be easily used in any urban watershed.