WorldWideScience

Sample records for polar wander paths

  1. True polar wander on convecting planets

    Science.gov (United States)

    Rose, Ian Robert

    the characteristic size of moment of inertia anomalies decreases with higher Ra, but that the characteristic response time for TPW also decreases. These two effects approximately cancel. However, the orientation of the principal axes of the moment of inertia becomes less stable to perturbations at high Ra, thereby increasing the rate of TPW. Overall, I find that a more vigorously convecting planet is more likely to experience large TPW events. If early Earth had more vigorous convection, it may have experienced more TPW than present-day Earth. Flow induced by density anomalies in the mantle deflects free surfaces at the surface and the CMB, and the mass anomalies due to these deflections contribute to the moment of inertia. A full accounting of the moment of inertia anomalies must include these surface effects. Numerical models of mantle convection with a free surface have suffered from numerical sloshing instabilities. I analyze the sloshing instability by constructing a generalized eigenvalue problem for the relaxation time spectrum. The minimum relaxation time of the spectrum sets the maximum stable timestep. This analysis gives the first quantitative explanation for why existing techniques for stabilizing geodynamic simulations with a free surface work. I also use this perspective to construct an alternative stabilization scheme based on nonstandard finite differences. This scheme has a single parameter, given by an estimate of the minimum relaxation time, and allows for still larger timesteps. Finally, I develop a new method for analyzing apparent polar wander (APW) paths described by sequences of paleomagnetic poles. Existing techniques, such as spline fits and running means, do not fully account for the uncertainties in the position and timing of paleomagnetic pole paths. Furthermore, they impose regularization on the solution, and the resulting uncertainties are difficult to interpret. Our technique is an extension of paleomagnetic Euler pole (PEP) analysis. I

  2. Rapid True Polar Wander Oscillations Preserved In Continuous Orosirian Strata

    Science.gov (United States)

    Mitchell, R. N.; Hoffman, P. F.; Brenner, A.; Xu, X.; Evans, D. A.; Bowring, S. A.; Bleeker, W.

    2014-12-01

    Previous paleomagnetic study of the Orosirian (2050-1800 Ma) Great Slave Supergroup, well exposed on islands in Great Slave Lake on the southeastern margin of the Slave craton, revealed evidence of a regularly reversing, or oscillatory, apparent polar wander path. The paleogeographic utility of paleopoles from the Great Slave Supergroup has been brought into question owing to the possibility of vertical-axis rotations associated with the McDonald transcurrent fault array, but structural corrections can be applied. In a high-resolution paleomagnetic re-sampling of portions of the Great Slave Supergroup, concentrating on the Pethei and Christie Bay Groups in particular, we demonstrate systematic and correlative shifts in declination within structurally uniform homoclinal sections. Positive fold tests further substantiate the primary nature of the paleomagnetic oscillations. Smooth, albeit rapid, declination changes preserved within and between our Great Slave Supergroup sections cannot be trivially explained by structural rotation. True polar wander oscillations (expressed as declination variation locally) may be used to correlate Orosirian strata regionally and globally. Geochronological refinement of the Great Slave Supergroup, both directly and indirectly, should help facilitate any such correlations and those with intrusive rocks both locally and globally. Unconformably overlain by the Et-Then Group that is contemporaneous with the McDonald Fault system, the Great Slave basin and intrusive Compton laccoliths pre-date transcurrent faulting. Increased precision achieved using modern U-Pb (zircon) geochronologic methods on the ca. 1865 Ma Compton laccoliths calibrates the minimum age constraint for Great Slave deposition. Additionally, magnetic susceptibility of a ~350 m-thick section of the Pethei Group reveals a hierarchy of cycles. If interpreted as astronomical cycles, possibly expressed through the effects of insolation on biogenic carbonate precipitation

  3. Apparent Polar Wander of the Pacific Plate and Pacific Hotspots: Implications for True Polar Wander and Hotspot Fixity

    Science.gov (United States)

    Gordon, R. G.; Horner-Johnson, B. C.; Petronotis, K. E.; Acton, G. D.

    2004-05-01

    Whether the apparent polar wander (APW) path of the Indo-Atlantic hotspots is a record of true polar wander could be tested from a detailed APW path of the Pacific plate, the motion of which can be estimated relative to the hotpots independently of reconstructions in the Atlantic and Indian Ocean basins. Such an APW path has previously been lacking because of the difficulty in obtaining fully oriented paleomagnetic samples from oceanic plates. We present an APW path for the Pacific plate and for the hotspots of the Pacific basin. Our Pacific plate APW path from 125 Ma to the present is based mainly on the analysis of the skewness of marine magnetic anomalies due to seafloor spreading and is determined with better accuracy and resolution from 32 Ma to 81 Ma than is the APW path of any continent. Our path is defined by eleven paleomagnetic poles from non-overlapping age windows. Nine of these poles, those with ages from 32 Ma to 81 Ma, are determined from skewness analysis of 1563 crossings of marine magnetic anomalies due to seafloor spreading. They reveal the APW of the Pacific plate over this time interval with an accuracy and age-resolution far superior to other data sets. The skewness-only portion of the path indicates northward motion of the Pacific plate with 3 main swings in declination, clockwise from 81 Ma to 68 Ma, counterclockwise from 68 Ma to 40 Ma, and clockwise from 40 Ma to the present. The older two poles are from combinations of data types. There is no significant motion of the pole from 125 Ma to 88 Ma, but there is a sudden large counterclockwise shift of the pole in the brief interval from 88 to 81 Ma. This large and rapid shift of the pole is strongly supported by paleocolatitude data from azimuthally unoriented vertical cores of igneous rock obtained by deep sea drilling. In a reference frame attached to the Pacific hotspots, the spin axis lay near 80°N, 160°E during mid-Cenozoic time (32-40 Ma), near 80°N, 210°E during early Cenozoic time

  4. Jurassic–Cretaceous low paleolatitudes from the circum-Black Sea region Crimea and Pontides) due to True Polar Wander

    NARCIS (Netherlands)

    Meijers, M.J.M.; Langereis, C.G.; van Hinsbergen, D.J.J.; Kaymakcl, N.; Stephenson, R.A.

    2010-01-01

    In a recent study, paleomagnetic and paleoenvironmental data from Adria (as part of the African plate) suggest a trend toward much lower (~15°) latitudes from Early Jurassic to Earliest Cretaceous at the position of Adria than suggested by the apparent polar wander (APW) paths. The smoothing of

  5. Rotational inertia of continents: A proposed link between polar wandering and plate tectonics

    Science.gov (United States)

    Kane, M.F.

    1972-01-01

    A mechanism is proposed whereby displacement between continents and the earth's pole of rotation (polar wandering) gives rise to latitudinal transport of continental plates (continental drift) because of their relatively greater rotational inertia. When extended to short-term polar wobble, the hypothesis predicts an energy change nearly equivalent to the seismic energy rate.

  6. True Polar Wander of Enceladus From Topographic Data

    Science.gov (United States)

    Tajeddine, Radwan; Soderlund, Krista M.; Thomas, Peter C.; Helfenstein, Paul; Hedman, Matthew M.; Burns, Joseph A.; Schenk, Paul M.

    2016-10-01

    Besides the relative motion of lithospheric plates, the Earth as a whole moves with respect to its rotation pole, as shown by paleomagnetic, astrometric and geodetic measurements [1]. Such so-called true polar wander (TPW) occurs because our planet's moments of inertia change temporally owing to internal thermal convection and to the redistribution of surficial mass during ice ages. Thus, to conserve angular momentum while losing rotational energy, Earth's axis of maximum moment of inertia aligns with its spin axis. Theoreticians suspect similar reorientations of other celestial bodies but supporting evidence is fragmentary, at best [2]. Here we report the discovery of a global series of topographic lows on Saturn's satellite Enceladus indicating that this synchronously locked moon has undergone reorientation by ~55°. We use improved topographic data from spherical harmonic expansion of Cassini limb [3,4,5] and stereogrammetric [5,6,7] measurements to characterize regional topography over the surface of Enceladus. We identify a group of nearly antipodal basins orthogonal to a topographic basin chain tracing a non-equatorial circumglobal belt across Enceladus' surface. We argue that the belt and the antipodal regions are fossil remnants of old equator and poles, respectively. These lows are argued to arise from isostasic compensation [7,8] with their pattern reflecting variations in internal dynamics of the ice shell. Our hypothesis is consistent with many geological features visible in Cassini images [9].References:[1] Mitrovica, J.X. & Wahr, Annual Review of Earth and Planetary Sciences, 39, 577-616 (2011).[2] Matsuyama, I. et al. Annual Review of Earth and Planetary Sciences, 42, 605-634 (2014).[3] Thomas, P.C. et al. Icarus, 190, 573-584 (2007).[4] Thomas, P.C. Icarus, 208, 395-401 (2010).[5] Thomas, P.C. et al. Icarus, 264, 37-47 (2016).[6] Edwards, K. Photogrammetric Engineering and Remote Sensing, 53, 1219-1222 (1987).[7] Schenk, P.M. & McKinnon, W. B

  7. A full-Maxwell approach for large angle polar wander of viscoelastic bodies

    NARCIS (Netherlands)

    Hu, H.; van der Wal, W.; Vermeersen, L.L.A.

    2017-01-01

    For large-angle long-term true polar wander (TPW) there are currently two types of nonlinear methods which give approximated solutions: those assuming that the rotational axis coincides with the axis of maximum moment of inertia (MoI), which simplifies the Liouville equation, and those based on the

  8. Lower Cambrian-Ediacaran Paleogeography and True Polar Wander with New Paleomagnetic Constraints from West African Craton

    Science.gov (United States)

    Robert, B.; Besse, J.; Blein, O.; Greff-Lefftz, M.; Baudin, T.; Fernando, L.; Meslouh, S.; Belbadaoui, M.

    2014-12-01

    Paleomagnetic data from Laurentia and Baltica continents suggest fast large oscillations of the virtual geomagnetic poles (VGP) from high to low latitudes during the Ediacaran (635-542 Ma). These data are interpreted in the literature either as oscillations of the Earth magnetic dipole between polar and equatorial positions, or as True Polar Wander (TPW), implying a very fast tumbling of continents and perhaps, of whole Earth. In this study, we try to test these hypotheses by bringing new paleomagnetic data on volcanic series from another continent, the West African Craton (WAC). We have sampled well dated pyroclastic and lava flows from the Ouarzazate and Taroudant groups in the Anti-Atlas, (Morocco). 480 samples from 105 sites were thermally demagnetized in our laboratory. Our preliminary results highlight two major groups of directions, mainly carried by hematite, magnetite also contributing sometimes to the magnetization. The first group consists of a dual polarity high inclination direction that may represent the original magnetization. The observed paleolatitude is compatible with that predicted by the lower Cambrian-Ediacaran apparent polar wander path (APWP) of Gondwana, assuming that the WAC was already accreted to Gondwana at this age. Nevertheless, a complete agreement between our pole and the APWP needs a local rotation of around 80° on a vertical axis. The second group displays a single polarity direction, with a shallow inclination and a south-east declination. This direction is close to the expected direction derived from the Permo-Carboniferous segment of the Gondwana APWP, and may represent a remagnetization acquired during the Kiaman reversed polarity superchron. Our preliminary paleomagnetic results thus display large changes in the VGP position, as also evidenced by others on Baltica and Laurentia. However, their interpretation does not favor TPW episodes or equatorial Earth magnetic dipole during the lower Cambrian-Ediacaran periods, but

  9. The evolution of climate. [climatic effects of polar wandering and continental drift

    Science.gov (United States)

    Donn, W. L.; Shaw, D.

    1975-01-01

    A quantitative evaluation is made of the climatic effects of polar wandering plus continental drift in order to determine wether this mechanism alone could explain the deterioration of climate that occurred from the warmth of Mesozoic time to the ice age conditions of the late Cenozoic. By way of procedure, to investigate the effect of the changing geography of the past on climate Adem's thermodynamic model was selected. The application of the model is discussed and preliminary results are given.

  10. Scaling rates of true polar wander in convecting planets and moons

    Science.gov (United States)

    Rose, Ian; Buffett, Bruce

    2017-12-01

    Mass redistribution in the convecting mantle of a planet causes perturbations in its moment of inertia tensor. Conservation of angular momentum dictates that these perturbations change the direction of the rotation vector of the planet, a process known as true polar wander (TPW). Although the existence of TPW on Earth is firmly established, its rate and magnitude over geologic time scales remain controversial. Here we present scaling analyses and numerical simulations of TPW due to mantle convection over a range of parameter space relevant to planetary interiors. For simple rotating convection, we identify a set of dimensionless parameters that fully characterize true polar wander. We use these parameters to define timescales for the growth of moment of inertia perturbations due to convection and for their relaxation due to true polar wander. These timescales, as well as the relative sizes of convective anomalies, control the rate and magnitude of TPW. This analysis also clarifies the nature of so called "inertial interchange" TPW events, and relates them to a broader class of events that enable large and often rapid TPW. We expect these events to have been more frequent in Earth's past.

  11. Model of climate evolution based on continental drift and polar wandering

    Science.gov (United States)

    Donn, W. L.; Shaw, D. M.

    1977-01-01

    The thermodynamic meteorologic model of Adem is used to trace the evolution of climate from Triassic to present time by applying it to changing geography as described by continental drift and polar wandering. Results show that the gross changes of climate in the Northern Hemisphere can be fully explained by the strong cooling in high latitudes as continents moved poleward. High-latitude mean temperatures in the Northern Hemisphere dropped below the freezing point 10 to 15 m.y. ago, thereby accounting for the late Cenozoic glacial age. Computed meridional temperature gradients for the Northern Hemisphere steepened from 20 to 40 C over the 200-m.y. period, an effect caused primarily by the high-latitude temperature decrease. The primary result of the work is that the cooling that has occurred since the warm Mesozoic period and has culminated in glaciation is explainable wholly by terrestrial processes.

  12. Strike-Slip Fault Patterns on Europa: Obliquity or Polar Wander?

    Science.gov (United States)

    Rhoden, Alyssa Rose; Hurford, Terry A.; Manga, Michael

    2011-01-01

    Variations in diurnal tidal stress due to Europa's eccentric orbit have been considered as the driver of strike-slip motion along pre-existing faults, but obliquity and physical libration have not been taken into account. The first objective of this work is to examine the effects of obliquity on the predicted global pattern of fault slip directions based on a tidal-tectonic formation model. Our second objective is to test the hypothesis that incorporating obliquity can reconcile theory and observations without requiring polar wander, which was previously invoked to explain the mismatch found between the slip directions of 192 faults on Europa and the global pattern predicted using the eccentricity-only model. We compute predictions for individual, observed faults at their current latitude, longitude, and azimuth with four different tidal models: eccentricity only, eccentricity plus obliquity, eccentricity plus physical libration, and a combination of all three effects. We then determine whether longitude migration, presumably due to non-synchronous rotation, is indicated in observed faults by repeating the comparisons with and without obliquity, this time also allowing longitude translation. We find that a tidal model including an obliquity of 1.2?, along with longitude migration, can predict the slip directions of all observed features in the survey. However, all but four faults can be fit with only 1? of obliquity so the value we find may represent the maximum departure from a lower time-averaged obliquity value. Adding physical libration to the obliquity model improves the accuracy of predictions at the current locations of the faults, but fails to predict the slip directions of six faults and requires additional degrees of freedom. The obliquity model with longitude migration is therefore our preferred model. Although the polar wander interpretation cannot be ruled out from these results alone, the obliquity model accounts for all observations with a value

  13. Paleomagnetism of a well-dated marine succession in South China: A possible Late Cambrian true polar wander (TPW)

    Science.gov (United States)

    Jiao, Wen-Jun; Li, Yong-Xiang; Yang, Zhen-Yu

    2018-04-01

    The Cambrian true polar wander (TPW) hypothesis remains controversial largely because of the uncertainties in the quality and/or fidelity of the paleomagnetic data as well as their chronological control. Testing the TPW hypothesis requires high-quality paleomagnetic data of sufficient spatial and temporal resolutions. Here, we present paleomagnetic results of a continuous Cambrian shallow marine succession from South China where available detailed biostratigraphy provides exceptional chronological constraints. Forty-three sites of paleomagnetic samples were collected from this limestone-dominated succession. Stepwise thermal demagnetization generally reveals three-component magnetizations. Low- and intermediate-temperature components can be cleaned by ∼330 °C, and the high-temperature component (HTC) was isolated typically from ∼350 to ∼450 °C. A positive fold test and the presence of reversed polarity in the strata, together with rock magnetic data as well as the scanning electron microscopic (SEM) and transmission electron microscopic (TEM) results, collectively suggest that the HTCs are likely primary. A directional shift of the HTCs occurs between the lower-middle Cambrian and the upper Cambrian strata in the succession and is tentatively interpreted to indicate a ∼57° polar wander from ∼500.5 to 494 Ma. Because the rate of polar wander is too fast to be a tectonic origin, this polar wander is interpreted to represent a Late Cambrian TPW. This TPW appears coeval with the Steptoean positive carbon isotope excursion (SPICE) and the major trilobite mass extinctions, suggesting a potential link between the TPW and the Late Cambrian biotic and climatic changes. Because the proposed TPW event is exceptionally well-dated, it should be testable through examination of other worldwide sections.

  14. The tidal-rotational shape of the Moon and evidence for polar wander.

    Science.gov (United States)

    Garrick-Bethell, Ian; Perera, Viranga; Nimmo, Francis; Zuber, Maria T

    2014-08-14

    The origin of the Moon's large-scale topography is important for understanding lunar geology, lunar orbital evolution and the Moon's orientation in the sky. Previous hypotheses for its origin have included late accretion events, large impacts, tidal effects and convection processes. However, testing these hypotheses and quantifying the Moon's topography is complicated by the large basins that have formed since the crust crystallized. Here we estimate the large-scale lunar topography and gravity spherical harmonics outside these basins and show that the bulk of the spherical harmonic degree-2 topography is consistent with a crust-building process controlled by early tidal heating throughout the Moon. The remainder of the degree-2 topography is consistent with a frozen tidal-rotational bulge that formed later, at a semi-major axis of about 32 Earth radii. The probability of the degree-2 shape having both tidal-heating and frozen shape characteristics by chance is less than 1%. We also infer that internal density contrasts eventually reoriented the Moon's polar axis by 36 ± 4°, to the configuration we observe today. Together, these results link the geology of the near and far sides, and resolve long-standing questions about the Moon's large-scale shape, gravity and history of polar wander.

  15. Ion Concentration Polarization by Bifurcated Current Path.

    Science.gov (United States)

    Kim, Junsuk; Cho, Inhee; Lee, Hyomin; Kim, Sung Jae

    2017-07-11

    Ion concentration polarization (ICP) is a fundamental electrokinetic process that occurs near a perm-selective membrane under dc bias. Overall process highly depends on the current transportation mechanisms such as electro-convection, surface conduction and diffusioosmosis and the fundamental characteristics can be significantly altered by external parameters, once the permselectivity was fixed. In this work, a new ICP device with a bifurcated current path as for the enhancement of the surface conduction was fabricated using a polymeric nanoporous material. It was protruded to the middle of a microchannel, while the material was exactly aligned at the interface between two microchannels in a conventional ICP device. Rigorous experiments revealed out that the propagation of ICP layer was initiated from the different locations of the protruded membrane according to the dominant current path which was determined by a bulk electrolyte concentration. Since the enhancement of surface conduction maintained the stability of ICP process, a strong electrokinetic flow associated with the amplified electric field inside ICP layer was significantly suppressed over the protruded membrane even at condensed limit. As a practical example of utilizing the protruded device, we successfully demonstrated a non-destructive micro/nanofluidic preconcentrator of fragile cellular species (i.e. red blood cells).

  16. From polar wander to dynamic planet: A tribute to Keith Runcorn

    Science.gov (United States)

    Girdler, R.W.

    1998-01-01

    The evolution of Keith Runcorn's ideas from the static, elastic Earth of Jeffreys to a dynamic, convecting planet are presented based on discussions as his colleague over 25 years from 1963 to his retirement in 1988. Keith reached the concept of a dynamic planet by way of polar wander and continental drift using palaeomagnetism with great zeal. It took some time for Keith to convince himself of the reality of continental drift. Once convinced, he became an evangelist converting others and enthusiastically pursuing possible mechanisms for explaining it, homing in on mantle convection. To establish the nature and history of mantle convection his interests ranged from the world rift system and satellite gravity anomalies to the radiometric age peaks. A great step forward occurred when we realised that a region of uprising convection was not necessary under all the rifts as had been commonly advocated in the 1960s and that the mid-Atlantic, African and Indian Ocean rifts could be equally well explained by one large region of upwelling mantle convection. It was also realised that the plate convergence zones (island arcs, trenches and deep focus earthquakes) were much better correlated with the satellite gravity anomalies and it was much easier to locate the possible regions of downwelling mantle convection. Now, seismic tomography helps to establish the nature of mantle convection and it appears that relations among the Earth's surface features, the geoid anomalies and peturbations of mantle seismic velocities are near to being established. In the next few years a far better and accurate picture of the geometry of mantle convection so enthusiastically advocated by Keith Runcorn is likely to be seen.

  17. Anomalous Late Jurassic motion of the Pacific Plate with implications for true polar wander

    Science.gov (United States)

    Fu, Roger R.; Kent, Dennis V.

    2018-05-01

    True polar wander, or TPW, is the rotation of the entire mantle-crust system about an equatorial axis that results in a coherent velocity contribution for all lithospheric plates. One of the most recent candidate TPW events consists of a ∼30° rotation during Late Jurassic time (160-145 Ma). However, existing paleomagnetic documentation of this event derives exclusively from continents, which compose less than 50% of the Earth's surface area and may not reflect motion of the entire mantle-crust system. Additional paleopositional information from the Pacific Basin would significantly enhance coverage of the Earth's surface and allow more rigorous testing for the occurrence of TPW. We perform paleomagnetic analyses on core samples from Ocean Drilling Program (ODP) Site 801B, which were taken from the oldest available Pacific crust, to determine its paleolatitude during the Late Jurassic and Early Cretaceous (167-133 Ma). We find that the Pacific Plate underwent a steady southward drift of 0.49°-0.74° My-1 except for an interval between Kimmeridgian and Tithonian time (157-147 Ma), during which it underwent northward motion at 1.45° ± 0.76° My-1 (1σ). This trajectory indicates that the plates of the Pacific Basin participated in the same large-amplitude (∼30°) rotation as continental lithosphere in the 160-145 Ma interval. Such coherent motion of a large majority of the Earth's surface strongly supports the occurrence of TPW, suggesting that a combination of subducting slabs and rising mantle plumes was sufficient to significantly perturb the Earth's inertia tensor in the Late Jurassic.

  18. A Full-Maxwell Approach for Large-Angle Polar Wander of Viscoelastic Bodies

    Science.gov (United States)

    Hu, H.; van der Wal, W.; Vermeersen, L. L. A.

    2017-12-01

    For large-angle long-term true polar wander (TPW) there are currently two types of nonlinear methods which give approximated solutions: those assuming that the rotational axis coincides with the axis of maximum moment of inertia (MoI), which simplifies the Liouville equation, and those based on the quasi-fluid approximation, which approximates the Love number. Recent studies show that both can have a significant bias for certain models. Therefore, we still lack an (semi)analytical method which can give exact solutions for large-angle TPW for a model based on Maxwell rheology. This paper provides a method which analytically solves the MoI equation and adopts an extended iterative procedure introduced in Hu et al. (2017) to obtain a time-dependent solution. The new method can be used to simulate the effect of a remnant bulge or models in different hydrostatic states. We show the effect of the viscosity of the lithosphere on long-term, large-angle TPW. We also simulate models without hydrostatic equilibrium and show that the choice of the initial stress-free shape for the elastic (or highly viscous) lithosphere of a given model is as important as its thickness for obtaining a correct TPW behavior. The initial shape of the lithosphere can be an alternative explanation to mantle convection for the difference between the observed and model predicted flattening. Finally, it is concluded that based on the quasi-fluid approximation, TPW speed on Earth and Mars is underestimated, while the speed of the rotational axis approaching the end position on Venus is overestimated.

  19. On the Impact Origin of Phobos and Deimos. II. True Polar Wander and Disk Evolution

    Science.gov (United States)

    Hyodo, Ryuki; Rosenblatt, Pascal; Genda, Hidenori; Charnoz, Sébastien

    2017-12-01

    Phobos and Deimos are the two small Martian moons, orbiting almost on the equatorial plane of Mars. Recent works have shown that they can accrete within an impact-generated inner dense and outer light disk, and that the same impact potentially forms the Borealis basin, a large northern hemisphere basin on the current Mars. However, there is no a priori reason for the impact to take place close to the north pole (Borealis present location), nor to generate a debris disk in the equatorial plane of Mars (in which Phobos and Deimos orbit). In this paper, we investigate these remaining issues on the giant impact origin of the Martian moons. First, we show that the mass deficit created by the Borealis impact basin induces a global reorientation of the planet to realign its main moment of inertia with the rotation pole (True Polar Wander). This moves the location of the Borealis basin toward its current location. Next, using analytical arguments, we investigate the detailed dynamical evolution of the eccentric inclined disk from the equatorial plane of Mars that is formed by the Martian-moon-forming impact. We find that, as a result of precession of disk particles due to the Martian dynamical flattening J 2 term of its gravity field and particle–particle inelastic collisions, eccentricity and inclination are damped and an inner dense and outer light equatorial circular disk is eventually formed. Our results strengthen the giant impact origin of Phobos and Deimos that can finally be tested by a future sample return mission such as JAXA’s Martian Moons eXploration mission.

  20. Anomalous Late Jurassic motion of the Pacific Plate with implications for true polar wander

    Science.gov (United States)

    Fu, R. R.; Kent, D.

    2017-12-01

    True polar wander, or TPW, is the rotation of the entire mantle-crust system that results in simultaneous change in latitude and orientation for all lithospheric plates. One of the most recent candidate TPW events consists of a 30˚ rotation during Late Jurassic time (160 - 145 Ma). However, existing paleomagnetic documentation of this event derives exclusively from continental studies. Because all major landmasses except China were connected directly or via spreading centers in the Late Jurassic, the velocities of these continents were mutually constrained and their motion as a group over the underlying mantle would be indistinguishable from TPW using only continental data. On the other hand, plates of the Pacific Basin constituted a kinematically independent domain, interfacing with continents at subduction zones and slip-strike boundaries. Coherent motion of both Pacific Basin and continental plates would therefore indicate uniform motion of virtually the entire lithosphere, providing a means to distinguish TPW from continental drift. We performed thermal demagnetization on remaining samples from Ocean Drilling Program (ODP) Site 801B, which were cored from the oldest sampled oceanic crust in the Western Pacific, to determine its change in paleolatitude during the Late Jurassic and Early Cretaceous (167 - 134 Ma). We find that the Pacific Plate likely underwent a steady southward drift during this time period, consistent with previous results from magnetic anomalies, except for an episode of northward motion between Oxfordian and Tithonian time (161 - 147 Ma). Although the amplitude of this northward shift is subject to significant uncertainty due to the sparse recovery of core samples, the trajectory of the Pacific Plate is most simply explained by TPW in the 160 - 145 Ma interval as inferred from continental data. Furthermore, such an interpretation is consistent with the sense of shear inferred at the Farallon-North American Plate boundary, whereas uniform

  1. Retracing the path of planar cell polarity.

    Science.gov (United States)

    Schenkelaars, Quentin; Fierro-Constain, Laura; Renard, Emmanuelle; Borchiellini, Carole

    2016-04-02

    The Planar Cell Polarity pathway (PCP) has been described as the main feature involved in patterning cell orientation in bilaterian tissues. Recently, a similar phenomenon was revealed in cnidarians, in which the inhibition of this pathway results in the absence of cilia orientation in larvae, consequently proving the functional conservation of PCP signaling between Cnidaria and Bilateria. Nevertheless, despite the growing accumulation of databases concerning basal lineages of metazoans, very few information concerning the existence of PCP components have been gathered outside of Bilateria and Cnidaria. Thus, the origin of this module or its prevalence in early emerging metazoans has yet to be elucidated. The present study addresses this question by investigating the genomes and transcriptomes from all poriferan lineages in addition to Trichoplax (Placozoa) and Mnemiopsis (Ctenophora) genomes for the presence of the core components of this pathway. Our results confirm that several PCP components are metazoan innovations. In addition, we show that all members of the PCP pathway, including a bona fide Strabismus ortholog (Van gogh), are retrieved only in one sponge lineage (Homoscleromorpha) out of four. This highly suggests that the full PCP pathway dates back at least to the emergence of homoscleromorph sponges. Consequently, several secondary gene losses would have occurred in the three other poriferan lineages including Amphimedon queenslandica (Demospongiae). Several proteins were not retrieved either in placozoans or ctenophores leading us to discuss the difficulties to predict orthologous proteins in basally branching animals. Finally, we reveal how the study of multigene families may be helpful to unravel the relationships at the base of the metazoan tree. The PCP pathway antedates the radiation of Porifera and may have arisen in the last common ancestor of animals. Oscarella species now appear as key organisms to understand the ancestral function of PCP

  2. True Polar Wander and Hotspot Fixity: A Paleomagnetic Investigation of the Skewness of Magnetic Anomaly 12r (32 Ma B.P.) on the Pacific Plate

    Science.gov (United States)

    Gordon, R. G.; Horner-Johnson, B. C.

    2010-12-01

    Prior studies have shown that Pacific hotspots and Indo-Atlantic hotspots have moved in approximate unison relative to the spin axis since 65 Ma B.P. [Morgan, 1981; Gordon and Cape, 1981; Gordon, 1982] and since 56 Ma B.P. [Petronotis et al., 1994], which is most simply interpreted as true polar wander. In contrast, Pacific hotspots and Indo-Atlantic hotspots give conflicting results for 72 Ma B.P. and for 81 Ma B.P., which may indicate motion between Pacific hotspots and Indo-Atlantic hotspots [Tarduno and Cottrell, 1997; Petronotis et al., 1999; Tarduno et al., 2003]. Thus it is important to estimate Pacific plate apparent polar wander (APW) for more time intervals. From such estimates the APW of Pacific hotspots can be inferred and compared with that of Indo-Atlantic hotspots [e.g., Besse and Courtillot 2002]. Here we present a study of the skewness of anomaly 12r between the Galapagos and Clipperton and between the Clipperton and Clarion fracture zones. We chose this region for several reasons: First, numerical experiments, like those conducted by Acton and Gordon [1991], indicate that magnetic profiles between the Galapagos and Clarion fracture zones should contain the most information about the Pacific plate paleomagnetic pole for chron C12r (32 Ma B.P.). Second, in these two spreading rate corridors, spreading half rates range from 72 to 86 mm/a and therefore have negligible anomalous skewness, given that they exceed ≈50 mm/a [Roest et al., 1992; Dyment et al. 1994]. Third, vector aeromagnetic profiles are available for analysis. One of the challenges to interpreting magnetic anomalies in low latitudes where the anomalies strike nearly north-south is the very low amplitude of the signal relative to the noise, the latter of which can be especially intense near the present magnetic equator due to the amplification of diurnal variation by the equatorial electrojet. Previously we showed that vector aeromagnetic profiles record low-latitude Pacific plate

  3. TOVS Pathfinder Path-P Daily and Monthly Polar Gridded Atmospheric Parameters, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The TIROS-N Operational Vertical Sounder (TOVS) Polar Pathfinder (Path-P) data set consists of gridded daily and monthly Arctic and Antarctic atmospheric data...

  4. TOVS Pathfinder Path-P Daily and Monthly Polar Gridded Atmospheric Parameters

    Data.gov (United States)

    National Aeronautics and Space Administration — The TIROS-N Operational Vertical Sounder (TOVS) Polar Pathfinder (Path-P) data set consists of gridded daily and monthly Arctic and Antarctic atmospheric data...

  5. Polarization measurements through space-to-ground atmospheric propagation paths by using a highly polarized laser source in space.

    Science.gov (United States)

    Toyoshima, Morio; Takenaka, Hideki; Shoji, Yozo; Takayama, Yoshihisa; Koyama, Yoshisada; Kunimori, Hiroo

    2009-12-07

    The polarization characteristics of an artificial laser source in space were measured through space-to-ground atmospheric transmission paths. An existing Japanese laser communication satellite and optical ground station were used to measure Stokes parameters and the degree of polarization of the laser beam transmitted from the satellite. As a result, the polarization was preserved within an rms error of 1.6 degrees, and the degree of polarization was 99.4+/-4.4% through the space-to-ground atmosphere. These results contribute to the link estimation for quantum key distribution via space and provide the potential for enhancements in quantum cryptography worldwide in the future.

  6. I. Episodic volcanism of tidally heated satellites with application to Io. II. Polar wander of a synchronously rotating satellite with application to Europa

    International Nuclear Information System (INIS)

    Ojakangas, G.W.

    1988-01-01

    Two examples of planetary bodies that may have coupled thermal and dynamical evolutions are investigated. The work is presented in three individual papers. The first example is that of a tidally heated satellite in an orbital resonance, for which the tidal dissipation rate is a strongly increasing function of the internal temperature. For such a satellite, a feedback mechanism exists between the orbital and thermal energies, which may lead to periodic variations in tidal heating within the satellite and its orbital eccentricity. A simple model of this mechanisms is presented in the first paper and is applied specifically to Io. The second examples is that of an ice shell on Europa, which is decoupled from the silicate core by a layer of liquid water. In the second paper, the spatially varying thickness that such a shell would have in thermal equilibrium with tidal dissipation within it, surface solar insolation and heat flow from the core is calculation for reasonable rheological laws for ice. The contribution of these variations in ice thickness to Europa's inertia tensor is estimated, and the implications for nonsynchronous rotation of Europa are discussed. In the third paper, a detailed dynamical model is developed, which demonstrates that such a shell may exhibit large-scale polar wander as it approaches thermal equilibrium, because of the destabilizing effect of the variations in ice thickness on the inertia tensor of the shell

  7. Dissolution Dynamic Nuclear Polarization capability study with fluid path

    DEFF Research Database (Denmark)

    Malinowski, Ronja Maja; Lipsø, Hans Kasper Wigh; Lerche, Mathilde Hauge

    2016-01-01

    Signal enhancement by hyperpolarization is a way of overcoming the low sensitivity in magnetic resonance; MRI in particular. One of the most well-known methods, dissolution Dynamic Nuclear Polarization, has been used clinically in cancer patients. One way of ensuring a low bioburden of the hyperp......Signal enhancement by hyperpolarization is a way of overcoming the low sensitivity in magnetic resonance; MRI in particular. One of the most well-known methods, dissolution Dynamic Nuclear Polarization, has been used clinically in cancer patients. One way of ensuring a low bioburden...

  8. TRANSPORT CORRIDOR "URAL INDUSTRIAL – URAL POLAR": PROBLEMS, EVOLUTION PATHS

    Directory of Open Access Journals (Sweden)

    N.V. Tabakov

    2007-06-01

    Full Text Available The article deals with the theoretic and methodological questions regarding the formation of a transport corridor "Urals industrial – Urals Polar". Analyzed are the main factors that affect the formation of the transport infrastructure. A big effect is centered around the world-view problem, which has to do with the occupation of a human, and the effect of it on nature. Put forth is the possibility to look upon the question of the formation of ma transport corridor "Urals industrial – Urals Polar" in the frame of the forming of the Ural-West-Siberian TPK, taking into account the global transport web.

  9. Polarity controlled reaction path and kinetics of thermal cis-to-trans isomerization of 4-aminoazobenzene.

    Science.gov (United States)

    Joshi, Neeraj Kumar; Fuyuki, Masanori; Wada, Akihide

    2014-02-20

    Spectral and kinetic behavior of thermal cis-to-trans isomerization of 4-aminoazobenzene (AAB) is examined in various solvents of different polarities. In contrast to azobenzene (AB), it is found the rate of thermal isomerization of AAB is highly dependent on solvent polarity. Accelerated rates are observed in polar solvents as compared to nonpolar solvents. Moreover, a decrease in the barrier height with an increase in medium polarity is observed. Our observations suggest that inversion is the preferred pathway in cis-to-trans thermal isomerization in a nonpolar medium; however, in a polar medium, the isomerization path deviates from the inversion route and rotational behavior is incorporated. Differences in the kinetics and in mechanisms of isomerization in different media are rationalized in terms of modulation in barrier height by polarity of the medium and solute-solvent interaction. It is found that kinetics as well as the mechanism of thermal isomerization in AAB is controlled by the polarity of the medium.

  10. TRANSPORT CORRIDOR "URAL INDUSTRIAL – URAL POLAR": PROBLEMS, EVOLUTION PATHS

    OpenAIRE

    N.V. Tabakov

    2007-01-01

    The article deals with the theoretic and methodological questions regarding the formation of a transport corridor "Urals industrial – Urals Polar". Analyzed are the main factors that affect the formation of the transport infrastructure. A big effect is centered around the world-view problem, which has to do with the occupation of a human, and the effect of it on nature. Put forth is the possibility to look upon the question of the formation of ma transport corridor "Urals industrial – Urals P...

  11. Tonian paleomagnetism of the red beds of Madiyi Formation, lower Banxi Group in South China: implications for pre-Sturtian climate, Rodinia reconstruction and true polar wander

    Science.gov (United States)

    Hanbiao, X.; Zhang, S.; Xiao, Q.; Li, H.; Chang, L.; Fu, H.; Liu, R.

    2017-12-01

    We present a new Tonian paleomagnetic pole from the red beds of ca. 810 Ma Madiyi Formation, lower Banxi Group in the central South China Block (SCB). Detailed thermal demagnetization reveals two distinct magnetic components among the samples. A low temperature component (LTC), removed from almost all the samples below 580°C, yielded a paleopole at 68.0°N, 211.7°E (A95=1.9) that is close to the pole of late Jurassic. The high temperature component (HTC), isolated between 580-690°C, gave a mean direction of D=310.0°, I=57.4°, α95=3.7 (108 samples of 13 sites) after bedding correction, corresponding to a paleomagnetic pole at 47.6°N, 46.7°E (A95=5.6°). The HTC passed a reversal test on 95% and 99% confidence level. Directional distribution of the HTC show significant elongation which may indicate inclination shallowing, and the inclination was corrected to 75.1° using E/I technique, corresponding to a paleolatitude at 60.8±3.4° of research area. The paleopole calculated from the E/I-corrected HTC is at 44.8°N, 80.2°E (A95=3.4°), being significantly distinct from any younger poles of the SCB. This new pole plus existing high quality paleomagnetic poles from the SCB demonstrate that the SCB experienced a polar-equatorial region drifting tendency from 825 Ma to Cambrian. The high-paleolatitude red beds rather than glacial sediments deposited in the SCB, combined with coeval widespread evaporative in other continents, possibly suggest pre-Cryogenian global greenhouse climate. In our reconstruction at 800 Ma, the SCB was placed on the northwest periphery of Rodinia, with its western margin adjacent to the northern India, rather than occupying a central position of Rodinia. The distribution of 825-750 Ma poles of the SCB, East Svalbard, Australia, Laurentia, India along a great arc may be associated with true polar wander around 800 Ma.

  12. Origin of ice diapirism, true polar wander, subsurface ocean, and tiger stripes of Enceladus driven by compositional convection

    Science.gov (United States)

    Freeman, J.; Stegman, D. R.; May, D.

    2009-12-01

    We consider the scenario in which the presence of ammonia in the bulk composition of Enceladus plays a pivotal role in its thermochemical evolution. Because ammonia reduces the melting temperature of the ice shell by 100 K below that of pure water ice, small amounts of tidal dissipation can power an “ammonia feedback” mechansim that leads to secondary differentiation of Enceladus within the ice shell. This leads to compositionally distinct zones at the base of the ice shell arranged such that a layer of lower density (and compositionally buoyant) pure water ice underlies the undifferentiated ammonia-dihydrate ice layer above. We then consider a large scale instability arising from the pure water ice layer, and use a numerical model to explore the dynamics of compositional convection within the ice shell of Enceladus. The instability of the layer can easily account for a diapir that is hemispherical in scale. As it rises to the surface, it co-advects the warm internal temperatures towards the outer layers of the satellite. This advected heat facilitates the generation of a subsurface ocean within the ice shell of Enceladus. This scenario can simultaneously account for the origin of asymmetry in surface deformation observed on Enceladus as well as two global features inferred to exist: the a large density anomaly within the interior and a subsurface ocean underneath the south polar region.

  13. Polar octahedral rotations: A path to new multifunctional materials

    International Nuclear Information System (INIS)

    Benedek, Nicole A.; Mulder, Andrew T.; Fennie, Craig J.

    2012-01-01

    Perovskite ABO 3 oxides display an amazing variety of phenomena that can be altered by subtle changes in the chemistry and internal structure, making them a favorite class of materials to explore the rational design of novel properties. Here we highlight a recent advance in which rotations of the BO 6 octahedra give rise to a novel form of ferroelectricity – hybrid improper ferroelectricity. Octahedral rotations also strongly influence other structural, magnetic, orbital, and electronic degrees of freedom in perovskites and related materials. Octahedral rotation-driven ferroelectricity consequently has the potential to robustly control emergent phenomena with an applied electric field. The concept of ‘functional’ octahedral rotations is introduced and the challenges for materials chemistry and the possibilities for new rotation-driven phenomena in multifunctional materials are explored. - Graphical abstract: A 3 B 2 O 7 and (A/A′)B 2 O 6 are two types of layered perovskites in which octahedral rotations induce ferroelectricity. Highlights: ► Recent progress on achieving ferroelectricity from rotations of the BO 6 octahedra in ABO 3 perovskite oxides is reviewed. ► The atomic scale layering of Pnma perovskites in two different ways leads to alternative structure realizations. ► The concept of ‘functional’ octahedral rotations is introduced as a path to electric-field control of emergent phenomena.

  14. Wandering Motive and Its Appeal on Reluctantly Wandering Franz Schubert

    Directory of Open Access Journals (Sweden)

    Dragana Jeremić-Molnar

    2016-02-01

    Full Text Available Franz Schubert was not generous in commenting his own creative procedures, or in revealing his artistic inspirations. Therefore, it is even today not clear why Wilhelm Müller’s collection of poems entitled Winter journey attracted Schubert so strongly that he was so determined to set it as a whole to the music. In this article the author mentions, and rejects as well, couple of commonly accepted interpretations. The path to the lieder cycle Winter journey was paved neither by Schubert’s identification with the main character – outcast overwhelmed by desperation and anticipation of the approaching death – and his strange ways of experiencing the world; neither by composer’s acceptance of impious beliefs hidden in Müller’s poems. The author argues that both poet and composer of Winter journey shared the affinity for the wandering (and wanderer motive which was one of the central topics in the rising romantic Weltanschauung. Schubert was dealing with this motive from 1815 until his death mainly in his lieder, sometimes in very complex manner. In order to understand the real nature of Schubert’s artistic rapprochement to the motive of wandering, the author was obliged to consider and, at the first place, evaluate the works of scholars (such as Theodor Adorno, David Gramit, and Jeffrey Perry who have been dealing with this problem. After that the author focuses her attention to the narrative entitled My dream, the most extensive and enigmatic writing left behind Schubert; she analyses the role of wandering in it, arguing that Schubert was participating in the spiritual currents of his time even unconsciously and trying to adapt them in order to serve as the solutions to his own existent ional dilemmas. Finally, she concludes that the composer was very sensitive for the complexity of the phenomena of wandering, when romantic Weltanschauung was at its peak, and eager to come to terms with this complexity artistically, paying the most

  15. In-service light path PMD (polarization mode dispersion) monitoring by PMD compensation.

    Science.gov (United States)

    Yao, X Steve; Chen, Xiaojun; Xia, T J; Wellbrock, Glenn; Chen, David; Peterson, Daniel; Zhang, Paul; Belisle, Ansel; Dong, Lei; Yu, Tao

    2010-12-20

    We describe a novel method of measuring PMD (polarization mode dispersion) of an in-service DWDM system by PMD compensation. We successfully demonstrate the method in a 1500-km ultra-long haul DWDM test bed. We further verify the feasibility of the method for in-service light path PMD monitoring in a field trial in a revenue-generating route in Verizon Network, and obtain an accurate PMD value without impacting live network traffic. The discrepancy between the measured and expected PMD values is less than 6% for all cases tested.

  16. [Travelers, mad, wandering].

    Science.gov (United States)

    Vaschetto, Emilio

    2014-01-01

    This article explores the notion of "wandering" through the use of some phenomena enrolled at the dawn of modernity such as the Rousseau dromomanie's philosopher and writer, the origin of the first mad traveler (Albert Dadas), epidemics of mad travelers Europe and romantic tourism (with renewed acquires significance in the "beat generation" of the twentieth century). These historical facts are "mounting" as play contemporary manifestations such as loss, disorientation, to lose one's way, and wandering without reducing them only to clinical psychosis. Readings of classic psychiatrists such as Régis, Foville, Sérieux and Capgras, Tissié, go hand in hand with the current readings of the philosopher Ian Hacking and critics of pop culture as S. Reynolds and D. Diederichsen, illustrating how the travel's phenomenon can make different subjective configurations depending on historical times. In conclusion it is noted that not only psychosis exposes the wandering soul of suffering but there are also subject positions (as will be exemplified in a clinical case) and go no further nesting wandering into human existence.

  17. The Wandering Jew

    Science.gov (United States)

    Woolf, Michael

    2018-01-01

    This essay examines the interaction between the myth of the Wandering Jew, diaspora history and the notion of cosmopolitanism. This is a paradoxical synthesis that points in several directions: towards the ideals embedded in international education; towards the roots of anti-Semitism; in the direction of the notion of cosmopolitanism as a crime…

  18. Paediatric Wandering Spleens in Malawi

    African Journals Online (AJOL)

    by a double layer of peritoneum. The wandering spleen is the rare description of an abnormally positioned spleen, which is thought to occur due to laxity, abnormality or absence of the aforementioned ligaments. The wandering spleen is noted to have a longer than normal pedicle, and because of its intraperitoneal location, ...

  19. A wandering liver

    International Nuclear Information System (INIS)

    Nichols, Brandon W.; Figarola, Maria S.; Standley, Todd B.

    2010-01-01

    A wandering liver has been described throughout modern medical literature as a rare entity. During the last few years, an increasing number of cases have been reported associated with colonic volvulus. We report a 17-year-old with a hypermobile liver seen on multiple radiographs and CT. The intraoperative findings demonstrated the liver in its normal anatomic position. We suggest that this entity is more common than thought, and the rise in incidence is likely secondary to increased utilization of pre-operative imaging of patients with colonic obstruction. Increased suspicion might result in further increased incidence of this exceedingly rare entity. (orig.)

  20. Wandering Between Practices

    DEFF Research Database (Denmark)

    Wallace, Jamie

    a consequence of the reflexive and material nature of art making.  This generally intuitive interaction between artist and work is the essence of ‘material thinking', ways of making in which thoughts and concepts are evolved through the interrelationship with the material handling and physical artwork....... By consciously framing art-making within a formal or ‘managed' structure it is proposed that ‘material thinking' can mediate a 'wandering' of concerns between the organisational sphere and the subjective, individual inquiry of the artist. Addittionally, because of the constantly changing dynamic of its own ways...

  1. Jesus as wandering prophetic wisdom teacher

    African Journals Online (AJOL)

    Jesus as wandering prophclic wisdom Icachcr lowing question needs attention: Is there an 'itinerary' of Jesus' wanderings, or may be a comprehensive plan of the intentions of his wanderings in the gospels? The fol lowing diagram gives an outline of the space, time and narrative according to the. Gospel of Mark. Scenes.

  2. Path Independent Polar Effective Plastic Strain (PEPS) Diagram for Sheet Forming

    Science.gov (United States)

    Yoon, Jeong Whan; Stoughton, Thomas B.

    This paper reviews a pre-strain effect on necking limit of sheet metal, and discusses the importance of this phenomenon to industrial applications. The paper also discusses a solution to this challenge including adaption of the stress diagram. A new type of forming limit diagram, based on a Polar plot of the Effective Plastic Strain (PEPS) is proposed that appears to be an effective solution to the problem of nonlinear effects, with advantages of the familiar strain-based diagram for linear loading, and without the strain-hardening limitations of the stress diagram, or non-intuitive aspects of the alternate Cartesian diagrams based on effective plastic strain. The benefits and limitations of each method are discussed.

  3. Can mind-wandering be timeless? Atemporal focus and aging in mind-wandering paradigms

    Science.gov (United States)

    Jackson, Jonathan D.; Weinstein, Yana; Balota, David A.

    2013-01-01

    Recent research has examined how often mind-wandering occurs about past vs. future events. However, mind-wandering may also be atemporal, although previous investigations of this possibility have not yielded consistent results. Indeed, it is unclear what proportion of mind-wandering is atemporal, and also how an atemporal response option would affect the future-oriented bias often reported during low-demand tasks used to measure mind-wandering. The present study examined self-reported (Experiment 1) and probe-caught (Experiment 2) mind-wandering using the low-demand Sustained Attention to Response Task (SART) in younger (18–30) and older (50–73) adults in an experimental paradigm developed to measure mind-wandering using Amazon's Mechanical Turk (Mturk). Across self-reported and probe-caught mind-wandering, the atemporal response option was used at least as frequently as past or future mind-wandering options. Although older adults reported far fewer mind-wandering events, they showed a very similar temporal pattern to younger adults. Most importantly, inclusion of the atemporal report option affected performance on the SART and selectively eliminated the prospective bias in self-reported mind-wandering, but not in probe-caught mind-wandering. These results suggest that both young and older participants are often not thinking of past or future events when mind-wandering, but are thinking of events that cannot easily be categorized as either. PMID:24137147

  4. Polarization sensitive subcutaneous and muscular imaging based on common path optical coherence tomography using near infrared source.

    Science.gov (United States)

    Han, Jae-Ho; Kang, Jin U; Song, Chul Gyu

    2011-08-01

    In this paper, we describe a polarization sensitive (PS) subcutaneous and muscular imaging system based on common path optical coherence tomography (CP-OCT) using a near infrared source. The axial and lateral resolutions of the PS-OCT system are 9 and 6 μm, respectively. The main goal of this work is to build a high-resolution and minimally invasive optical imager for examining various kinds of cutaneous substructures with intrinsic or form birefringence. The internal structural information is extracted by the real-time signal analysis (Fourier Transform) of the modulated spectral intensity depending on the beam and tissue birefringence. The preliminary results using fresh beef longissimus muscle and in vivo Rattus norvegicus (rat) show that it is possible to visualize the birefringence effect of the tissue collagen fibers in the samples in order to achieve superior image contrast and sensitivity for the detection of hidden dermal structures. Compared to conventional CP-OCT, the proposed PS-OCT system provides depth-resolved images, which reflect the tissue birefringence.

  5. Re-reading after mind wandering.

    Science.gov (United States)

    Varao-Sousa, Trish L; Solman, Grayden J F; Kingstone, Alan

    2017-09-01

    Though much research has been conducted on the causes and processes underlying mind wandering, relatively little has addressed what happens after an episode of mind wandering. We explore this issue in the context of reading. Specifically, by examining re-reading behaviours following mind wandering episodes. Results from 2 studies reveal that after mind wandering, participants re-read nearly half the time. This re-reading occurs whether mind wandering is self-caught or probe-caught, and it typically involves retracing a line or 2 of text. Based on subjective reports, it appears that individuals re-read when they feel that clarification of the text is needed, suggesting that a key concept of the text is missed during a mind wandering episode. Future work aimed at understanding how individuals refocus their attention following mind wandering in different settings should provide additional insights into the fluctuation of attentional focus and the immediate impact of a mind wandering episode. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  6. EXCHANGE OF THE WANDERING ALBATROSS DIOMEDEA ...

    African Journals Online (AJOL)

    The wandering albatrosses of the two island groups form a metapopulation that ideally should be conserved as a single unit. It is suggested that France and South Africa collaborate through the Agreement on the Conservation of Albatrosses and Petrels to effect an improved conservation status for the wandering albatrosses ...

  7. The neurotic wandering mind: An individual differences investigation of neuroticism, mind-wandering, and executive control.

    Science.gov (United States)

    Robison, Matthew K; Gath, Katherine I; Unsworth, Nash

    2017-04-01

    Cognitive psychology and cognitive neuroscience have recently developed a keen interest in the phenomenon of mind-wandering. People mind-wander frequently, and mind-wandering is associated with decreased cognitive performance. But why do people mind-wander so much? Previous investigations have focused on cognitive abilities like working memory capacity and attention control. But an individual's tendency to worry, feel anxious, and entertain personal concerns also influences mind-wandering. The Control Failure × Concerns model of mind-wandering. Psychological Bulletin, 136, 188-197] argues that individual differences in the propensity to mind-wander are jointly determined by cognitive abilities and by the presence of personally salient concerns that intrude on task focus. In order to test this model, we investigated individual differences in mind-wandering, executive attention, and personality with a focus on neuroticism. The results showed that neurotic individuals tended to report more mind-wandering during cognitive tasks, lower working memory capacity, and poorer attention control. Thus the trait of neuroticism adds an additional source of variance in the tendency to mind-wander, which offers support for the Control Failure × Concerns model. The results help bridge the fields of clinical psychology, cognitive psychology, affective neuroscience, and cognitive neuroscience as a means of developing a more complete understanding of the complex relationship between cognition, personality, and emotion.

  8. Wandering Skipper Survey Observations 2010 [ds666

    Data.gov (United States)

    California Department of Resources — The wandering skipper (Panoquina errans) is a small butterfly of the family Hesperiidae. It is identifiable by its rich dark brown color and cream-colored spots on...

  9. Driving with the wandering mind: the effect that mind-wandering has on driving performance.

    Science.gov (United States)

    Yanko, Matthew R; Spalek, Thomas M

    2014-03-01

    The principal objective of the present work was to examine the effects of mind state (mind-wandering vs. on-task) on driving performance in a high-fidelity driving simulator. Mind-wandering is thought to interfere with goal-directed thought. It is likely, then, that when driving, mind-wandering might lead to impairments in critical aspects of driving performance. In two experiments, we assess the extent to which mind-wandering interferes with responsiveness to sudden events, mean velocity, and headway distance. Using a car-following procedure in a high-fidelity driving simulator, participants were probed at random times to indicate whether they were on-task at that moment or mind-wandering. The dependent measures were analyzed based on the participant's response to the probe. Compared to when on-task, when mind-wandering participants showed longer response times to sudden events, drove at a higher velocity, and maintained a shorter headway distance. Collectively, these findings indicate that mind-wandering affects a broad range of driving responses and may therefore lead to higher crash risk. The results suggest that situations that are likely associated with mind-wandering (e.g., route familiarity) can impair driving performance.

  10. Occurrence Locations, Dipole Tilt Angle Effects, and Plasma Cloud Drift Paths of Polar Cap Neutral Density Anomalies

    Science.gov (United States)

    Lin, C. S.; Sutton, E. K.; Huang, C. Y.; Cooke, D. L.

    2018-02-01

    Polar cap neutral density anomaly (PCNDA) with large mass density enhancements over the background has been frequently observed in the polar cap during magnetic storms. By tracing field lines to the magnetosphere from the polar ionosphere, we divide the polar cap into two regions, an open field line (OFL) region with field lines connecting to the magnetopause boundary and a distant tail field line (TFL) region threaded with magnetotail lobe field lines. A statistical study of neutral density observed by the Challenging Minisatellite Payload satellite during major magnetic storms with Dst atmospheric disturbance could be generated in the nightside polar cap. From the PCNDA size and speed of sound at 400 km, we derive an initial energy deposition duration for producing traveling atmospheric disturbance in the range from 0.5 to 2.5 hr.

  11. Wandering spleen with a ten-time twisted vascular pedicle

    Directory of Open Access Journals (Sweden)

    Marta Peretti

    2016-12-01

    Full Text Available Torsion of a wandering spleen is a rare cause of acute abdomen in children, usually diagnosed with color-Doppler ultrasonography and enhanced computed tomography. We report a pediatric case of torsion of wandering spleen.

  12. Polar Expansion Dynamics in the Plant Kingdom: A Diverse and Multifunctional Journey on the Path to Pollen Tubes

    Directory of Open Access Journals (Sweden)

    David S. Domozych

    2013-03-01

    Full Text Available Polar expansion is a widespread phenomenon in plants spanning all taxonomic groups from the Charophycean Green Algae to pollen tubes in Angiosperms and Gymnosperms. Current data strongly suggests that many common features are shared amongst cells displaying polar growth mechanics including changes to the structural features of localized regions of the cell wall, mobilization of targeted secretion mechanisms, employment of the actin cytoskeleton for directing secretion and in many cases, endocytosis and coordinated interaction of multiple signal transduction mechanisms prompted by external biotic and abiotic cues. The products of polar expansion perform diverse functions including delivery of male gametes to the egg, absorption, anchorage, adhesion and photo-absorption efficacy. A comparative analysis of polar expansion dynamics is provided with special emphasis on those found in early divergent plants.

  13. THE OLDEST KNOWN BANDED WANDERING ALBATROSS ...

    African Journals Online (AJOL)

    The oldest known wandering albatross Diomedea exulans at the Prince Edward Islands is estimated to have been approximately half a century old when last recaptured in 2001. Demographic studies need to continue for several more decades before the true maximum longevity of the species becomes evident. Afr. J. mar.

  14. The polar year starts in March. Arctics promises. When the North path will be opened to maritime traffic

    International Nuclear Information System (INIS)

    Lepetit, V.; Remoue, A.

    2007-01-01

    From Greenland to Alaska and from the Barents sea to the Okhotsk sea, oil companies are performing exploratory drillings looking for the North pole black gold. Far away from being an utopia, this new conquest of the great north is organizing yet. The Arctic hydrocarbon reserves may represent 10% of the world reserves. Moreover, with the increasing melting of ice sheets, the Arctic path will be opened to navigation and exploration in less than 25 years. The great north territories are shared between eight countries (USA, Canada, Denmark, Island, Norway, Sweden, Finland and Russia) and leads to disputes about the limits of territorial waters. (J.S.)

  15. Mind Wandering, Sleep Quality, Affect and Chronotype: An Exploratory Study

    Science.gov (United States)

    Carciofo, Richard; Du, Feng; Song, Nan; Zhang, Kan

    2014-01-01

    Poor sleep quality impairs cognition, including executive functions and concentration, but there has been little direct research on the relationships between sleep quality and mind wandering or daydreaming. Evening chronotype is associated with poor sleep quality, more mind wandering and more daydreaming; negative affect is also a mutual correlate. This exploratory study investigated how mind wandering and daydreaming are related to different aspects of sleep quality, and whether sleep quality influences the relationships between mind wandering/daydreaming and negative affect, and mind wandering/daydreaming and chronotype. Three surveys (Ns = 213; 190; 270) were completed with Chinese adults aged 18–50, including measures of sleep quality, daytime sleepiness, mind wandering, daydreaming, chronotype and affect (positive and negative). Higher frequencies of mind wandering and daydreaming were associated with poorer sleep quality, in particular with poor subjective sleep quality and increased sleep latency, night-time disturbance, daytime dysfunction and daytime sleepiness. Poor sleep quality was found to partially mediate the relationships between daydreaming and negative affect, and mind wandering and negative affect. Additionally, low positive affect and poor sleep quality, in conjunction, fully mediated the relationships between chronotype and mind wandering, and chronotype and daydreaming. The relationships between mind wandering/daydreaming and positive affect were also moderated by chronotype, being weaker in those with a morning preference. Finally, while daytime sleepiness was positively correlated with daydream frequency, it was negatively correlated with a measure of problem-solving daydreams, indicating that more refined distinctions between different forms of daydreaming or mind wandering are warranted. Overall, the evidence is suggestive of a bi-directional relationship between poor sleep quality and mind wandering/daydreaming, which may be

  16. Torsion of Wandering Gallbladder following Colonoscopy

    Directory of Open Access Journals (Sweden)

    Sean R. Warfe

    2013-01-01

    Full Text Available Torsion of the gallbladder is an uncommon condition that may present as an acute abdomen. Its preoperative diagnosis can often be challenging due to its variable presentation, with specific sonographic signs seen infrequently. We describe, to our knowledge, the first case of torsion of a wandering gallbladder following a colonoscopy in a 69-year-old female who presented with acute abdominal pain after procedure. This was discovered intraoperatively, and after a subsequent cholecystectomy, she had an uncomplicated recovery.

  17. Young & restless: Validation of the Mind-Wandering Questionnaire (MWQ reveals disruptive impact of mind-wandering for youth

    Directory of Open Access Journals (Sweden)

    Michael D. Mrazek

    2013-08-01

    Full Text Available Mind-wandering is the focus of extensive investigation, yet until recently there has been no validated scale to directly measure trait levels of task-unrelated thought. Scales commonly used to assess mind-wandering lack face validity, measuring related constructs such as daydreaming or behavioral errors. Here we report four studies validating a Mind-Wandering Questionnaire (MWQ across college, high school, and middle school samples. The 5-item scale showed high internal consistency, as well as convergent validity with existing measures of mind-wandering and related constructs. Trait levels of mind-wandering, as measured by the MWQ, were correlated with task-unrelated thought measured by thought sampling during a test of reading comprehension. In both middle school and high school samples, mind-wandering during testing was associated with worse reading comprehension. By contrast, elevated trait levels of mind-wandering predicted worse mood, less life-satisfaction, greater stress, and lower self-esteem. By extending the use of thought sampling to measure mind-wandering among adolescents, our findings also validate the use of this methodology with younger populations. Both the MWQ and thought sampling indicate that mind-wandering is a pervasive – and problematic – influence on the performance and well-being of adolescents.

  18. Ted Irving and the Arc of APW Paths

    Science.gov (United States)

    Kent, D. V.

    2014-12-01

    Ted Irving's last two published papers neatly encapsulate his seminal contributions to the delineation of ever-important apparent polar wander (APW) paths. His final (210th) paper [Creer & Irving, 2012 Earth Sciences History] describes in detail how Ken Creer and he when still graduate students at Cambridge started to generate and assemble paleomagnetic data for the first APW path, for then only the UK; the paper was published 60 years ago and happened to be Ted's first [Creer, Irving & Runcorn, 1954 JGE]. Only 10 years later, there was already a lengthy reference list of paleomagnetic results available from most continents that had been compiled in pole lists he published in GJRAS from 1960 to 1965 and included in an appendix in his landmark book "Paleomagnetism" [Irving, 1964 Wiley] in support of wide ranging discussions of continental drift and related topics in chapters like 'Paleolatitudes and paleomeridians.' A subsequent innovation was calculating running means of poles indexed to a numerical geologic time scale [Irving, 1977 Nature], which with independent tectonic reconstructions as already for Gondwana allowed constructions of more detailed composite APW paths. His 1977 paper also coined Pangea B for an earlier albeit contentious configuration for the supercontinent that refuses to go away. Gliding over much work on APW tracks and hairpins in the Precambrian, we come to Ted's penultimate (209th) paper [Kent & Irving, 2010 JGR] in which individual poles from short-lived large igneous provinces were grouped and most sedimentary poles, many rather venerable, excluded as likely to be biased by variable degrees of inclination error. The leaner composite APW path helped to resurrect the Baja BC scenario of Cordilleran terrane motions virtually stopped in the 1980s by APW path techniques that relied on a few key but alas often badly skewed poles. The new composite APW path also revealed several major features, such as a huge polar shift of 30° in 15 Myr in the

  19. Beam wandering statistics of twin thin laser beam propagation under generalized atmospheric conditions.

    Science.gov (United States)

    Pérez, Darío G; Funes, Gustavo

    2012-12-03

    Under the Geometrics Optics approximation is possible to estimate the covariance between the displacements of two thin beams after they have propagated through a turbulent medium. Previous works have concentrated in long propagation distances to provide models for the wandering statistics. These models are useful when the separation between beams is smaller than the propagation path-regardless of the characteristics scales of the turbulence. In this work we give a complete model for these covariances, behavior introducing absolute limits to the validity of former approximations. Moreover, these generalizations are established for non-Kolmogorov atmospheric models.

  20. Wandering minds and wavering goals: Examining the relation between mind wandering and grit in everyday life and the classroom.

    Science.gov (United States)

    Ralph, Brandon C W; Wammes, Jeffrey D; Barr, Nathaniel; Smilek, Daniel

    2017-06-01

    Here we examined the relation between mind wandering and the personality trait of 'grit.' Our hypothesis was that because mind wandering leads to a disruption of momentary goal completion, the tendency to mind wander might be inversely related to the completion of long-term goals that require sustained interest and effort (i.e., grittiness). In Study 1 we used online questionnaires and found that in everyday life, the propensity to mind wander was negatively correlated with individuals' self-reported grittiness. Interestingly, the relation between mind wandering and grit was strongest for unintentional bouts of mind wandering (as compared with intentional mind wandering). We extended these findings in Study 2 by (a) using a more heterogeneous sample of participants, (b) including a measure of conscientiousness, and (c) including another measure of general perseverance. In addition to replicating our findings from Study 1, in Study 2 we found that the grit measure uniquely predicted spontaneous mind wandering over and above a measure of conscientiousness and an alternative measure of general perseverance. Lastly, in Study 3 we extend the relation between mind wandering and grit to the classroom, finding that mind wandering during university lectures was also related to self-reported grittiness. Taken together, we suggest that the propensity to experience brief lapses of attention is associated with the propensity to stick-with and complete long-term goals. We also provide evidence that when predicting mind wandering and inattention, measures of grit are not redundant with existing measure of conscientiousness and general perseverance. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  1. Polynomial skew-products with wandering Fatou-disks

    NARCIS (Netherlands)

    Peters, H.; Vivas, L.R.

    2016-01-01

    Until recently, little was known about the existence of wandering Fatou components for rational maps in more than one complex variables. In 2014, examples of wandering Fatou components were constructed in Astorg et al. [1] for polynomial skew-products with an invariant parabolic fiber. In 2004 Lilov

  2. Mind Wandering and the Incubation Effect in Insight Problem Solving

    Science.gov (United States)

    Tan, Tengteng; Zou, Hong; Chen, Chuansheng; Luo, Jin

    2015-01-01

    Although many anecdotes suggest that creative insights often arise during mind wandering, empirical research is still sparse. In this study, the number reduction task (NRT) was used to assess whether insightful solutions were related to mind wandering during the incubation stage of the creative process. An experience sampling paradigm was used to…

  3. Modeling mind-wandering: a tool to better understand distraction

    NARCIS (Netherlands)

    van Vugt, Marieke; Taatgen, Niels; Sackur, Jerome; Bastian, Mikael; Taatgen, Niels; van Vugt, Marieke; Borst, Jelmer; Mehlhorn, Katja

    2015-01-01

    When we get distracted, we may engage in mind-wandering, or task-unrelated thinking, which impairs performance on cognitive tasks. Yet, we do not have cognitive models that make this process explicit. On the basis of both recent experiments that have started to investigate mind-wandering and

  4. Detecting and Quantifying Mind Wandering during Simulated Driving.

    Science.gov (United States)

    Baldwin, Carryl L; Roberts, Daniel M; Barragan, Daniela; Lee, John D; Lerner, Neil; Higgins, James S

    2017-01-01

    Mind wandering is a pervasive threat to transportation safety, potentially accounting for a substantial number of crashes and fatalities. In the current study, mind wandering was induced through completion of the same task for 5 days, consisting of a 20-min monotonous freeway-driving scenario, a cognitive depletion task, and a repetition of the 20-min driving scenario driven in the reverse direction. Participants were periodically probed with auditory tones to self-report whether they were mind wandering or focused on the driving task. Self-reported mind wandering frequency was high, and did not statistically change over days of participation. For measures of driving performance, participant labeled periods of mind wandering were associated with reduced speed and reduced lane variability, in comparison to periods of on task performance. For measures of electrophysiology, periods of mind wandering were associated with increased power in the alpha band of the electroencephalogram (EEG), as well as a reduction in the magnitude of the P3a component of the event related potential (ERP) in response to the auditory probe. Results support that mind wandering has an impact on driving performance and the associated change in driver's attentional state is detectable in underlying brain physiology. Further, results suggest that detecting the internal cognitive state of humans is possible in a continuous task such as automobile driving. Identifying periods of likely mind wandering could serve as a useful research tool for assessment of driver attention, and could potentially lead to future in-vehicle safety countermeasures.

  5. A wandering spleen presenting as a hypogastric mass: case report

    African Journals Online (AJOL)

    raoul

    2012-02-21

    Feb 21, 2012 ... Misawa T, Yoshida K, Shiba H, Kobayashi S, Yanaga K. Wandering spleen with chronic torsion. Am J Surg. 2008 Apr;195(4):504-5. This article on PubMed. 7. Fiquet-Francois C, Belouadah M, Ludot H, Defauw B. Wandering spleen in children: multicenter retrospective study. J Pediatr Surg. 2010.

  6. Wandering spleen: a medical enigma, its natural history and rationalization.

    Science.gov (United States)

    Magowska, Anita

    2013-03-01

    Wandering spleen is a rare condition in which the spleen is not located in the left upper quadrant but is found lower in the abdomen or in the pelvic region because of the laxity of the peritoneal attachments. Many patients with wandering spleen are asymptomatic, hence the condition can be discovered only by abdominal examination or at a hospital emergency department if a patient is admitted to hospital because of severe abdominal pain, vomiting or obstipation. This article aims to provide a historical overview of wandering spleen diagnostics and surgical treatment supplemented with an analyses of articles on wandering spleen included in the PubMed database. One of the first clinical descriptions of a wandering spleen was written by Józef Dietl in 1854. The next years of vital importance are 1877 when A. Martin conducted the first splenectomy and in 1895 when Ludwik Rydygier carried out the first splenopexy to immobilize a wandering spleen. Since that time various techniques of splenectomy and splenopexy have been developed. Introducing medical technologies was a watershed in the development and treatment of wandering spleen, which is confirmed by the PubMed database. Despite the increased number of publications medical literature shows that a wandering spleen still remains a misdiagnosed condition, especially among children.

  7. An unusual case of acute wandering paralysis

    Directory of Open Access Journals (Sweden)

    Federico Bianchi

    2016-01-01

    Full Text Available The authors reported on a 63-year-old diabetic male who developed a strange wandering hemiparesis affecting first left side and then right side, not consistent with a right parasagittal meningioma nor with ischemic stroke. The subsequent rapid worsening of clinical picture, with occurrence of paraparesis, urinary incontinence and midthoracic sensory level, together with the evidence of leucocytosis, led to the diagnosis of a T6-T7 spondylodiscitis with spinal cord compression. The authors underlied the difficulties in diagnosing this condition in the setting of general hospital practice and the importance of clinical and neurological examination.

  8. An automated behavioral measure of mind wandering during computerized reading.

    Science.gov (United States)

    Faber, Myrthe; Bixler, Robert; D'Mello, Sidney K

    2018-02-01

    Mind wandering is a ubiquitous phenomenon in which attention shifts from task-related to task-unrelated thoughts. The last decade has witnessed an explosion of interest in mind wandering, but research has been stymied by a lack of objective measures, leading to a near-exclusive reliance on self-reports. We addressed this issue by developing an eye-gaze-based, machine-learned model of mind wandering during computerized reading. Data were collected in a study in which 132 participants reported self-caught mind wandering while reading excerpts from a book on a computer screen. A remote Tobii TX300 or T60 eyetracker recorded their gaze during reading. The data were used to train supervised classification models to discriminate between mind wandering and normal reading in a manner that would generalize to new participants. We found that at the point of maximal agreement between the model-based and self-reported mind-wandering means (smallest difference between the group-level means: M model = .310, M self = .319), the participant-level mind-wandering proportional distributions were similar and were significantly correlated (r = .400). The model-based estimates were internally consistent (r = .751) and predicted text comprehension more strongly than did self-reported mind wandering (r model = -.374, r self = -.208). Our results also indicate that a robust strategy of probabilistically predicting mind wandering in cases with poor or missing gaze data led to improved performance on all metrics, as compared to simply discarding these data. Our findings demonstrate that an automated objective measure might be available for laboratory studies of mind wandering during reading, providing an appealing alternative or complement to self-reports.

  9. Mind-Wandering in People with Hippocampal Damage.

    Science.gov (United States)

    McCormick, Cornelia; Rosenthal, Clive R; Miller, Thomas D; Maguire, Eleanor A

    2018-03-14

    Subjective inner experiences, such as mind-wandering, represent the fundaments of human cognition. Although the precise function of mind-wandering is still debated, it is increasingly acknowledged to have influence across cognition on processes such as future planning, creative thinking, and problem-solving and even on depressive rumination and other mental health disorders. Recently, there has been important progress in characterizing mind-wandering and identifying the associated neural networks. Two prominent features of mind-wandering are mental time travel and visuospatial imagery, which are often linked with the hippocampus. People with selective bilateral hippocampal damage cannot vividly recall events from their past, envision their future, or imagine fictitious scenes. This raises the question of whether the hippocampus plays a causal role in mind-wandering and, if so, in what way. Leveraging a unique opportunity to shadow people (all males) with bilateral hippocampal damage for several days, we examined, for the first time, what they thought about spontaneously, without direct task demands. We found that they engaged in as much mind-wandering as control participants. However, whereas controls thought about the past, present, and future, imagining vivid visual scenes, hippocampal damage resulted in thoughts primarily about the present comprising verbally mediated semantic knowledge. These findings expose the hippocampus as a key pillar in the neural architecture of mind-wandering and also reveal its impact beyond episodic memory, placing it at the heart of our mental life. SIGNIFICANCE STATEMENT Humans tend to mind-wander ∼30-50% of their waking time. Two prominent features of this pervasive form of thought are mental time travel and visuospatial imagery, which are often associated with the hippocampus. To examine whether the hippocampus plays a causal role in mind-wandering, we examined the frequency and phenomenology of mind-wandering in patients with

  10. Tracking arousal state and mind wandering with pupillometry.

    Science.gov (United States)

    Unsworth, Nash; Robison, Matthew K

    2018-04-13

    In four experiments, the association between arousal state and different mind-wandering states was examined. Participants performed a sustained attention task while pupil responses were continuously recorded. Periodically during the task, participants were presented with thought probes to determine if they were on task or mind wandering. Across the four experiments, the results suggested that in situations that promoted on-task behaviors and focused external attention, mind wandering was associated with lowered arousal, as seen by smaller tonic pupil diameters and smaller phasic pupillary responses. However, in situations that promoted a more internal focus of attention, there were no differences between on-task states and mind wandering in tonic pupil diameter (although differences emerged for phasic pupillary responses), suggesting similar arousal levels. Furthermore, across the four experiments, mind blanking and mind wandering dissociated in terms of whether the situation promoted focused external attention or focused internal attention. These results are broadly consistent with the notion that mind wandering is a heterogeneous construct, with different forms of mind wandering being associated with different arousal states, and suggest that a combination of behavioral and pupillary measures can be used to track these various states.

  11. Characterization of Mind Wandering using fNIRS

    Directory of Open Access Journals (Sweden)

    Gautier eDurantin

    2015-03-01

    Full Text Available Assessing whether someone is attending to a task has become importantfor educational and professional applications. Such attentional drifts are usually termed mind wandering. The purpose of the current study is to test to what extent a recent neural imaging modality can be used to detect mind wandering episodes. Functional near infra-red spectroscopy is a non-invasive neuro-imaging technique that has never been studied so far to measure mind wandering. The Sustained Attention to Response Task was used to assess when subjects attention leaves a primary task. 16-channel fNIRS data were collected over frontal cortices. We observed significant activations over the medial prefrontal cortex during mind wandering, a brain region associated with the default mode network. fNIRS data were used to classify mind wandering data above chance level. In line with previous brain-imaging studies of mind wandering, our results confirm the ability of fNIRS to detect Default Network activations in the context of mind wandering.

  12. Children’s Mental Time Travel during Mind Wandering

    Directory of Open Access Journals (Sweden)

    Qun eYe

    2014-08-01

    Full Text Available The prospective bias is a salient feature of mind wandering in healthy adults, yet little is known about the temporal focus of children’s mind wandering. In the present study, (I we developed the Temporal Focus of Mind Wandering Questionnaire for school-age children (TFMWQ-C, a 12-item scale with good test-retest reliability and construct validity. (II The criterion validity was tested by thought sampling in both Choice Reaction Time Task (CRT and Working Memory Task (WMT. A positive correlation was found between the temporal focus measured by the questionnaire and the one adopted during task-unrelated thoughts (TUTs by thought sampling probes, especially in the trait level of future-oriented mind wandering. At the same time, children who experienced more TUTs tended to show worse behavioral performance during tasks. (III The children in both tasks experienced more future-oriented TUTs than past-oriented ones, which was congruent with the results observed in adults; however, in contrast with previous research on adults, the prospective bias was not influenced by task demands. Together these results indicate that the prospective bias of mind wandering has emerged since the school age (9~13 years old, and that the relationship between mental time travel during mind wandering and the use of cognitive resources differs between children and adults. Our study provides new insights into how this interesting feature of mind wandering may adaptively contribute to the development of children’s mental time travel.

  13. Wandering accelerators throughout my life (1)

    International Nuclear Information System (INIS)

    Nakai, Kozi

    2009-01-01

    My wanderings about accelerators started being stimulated by nuclear physics activities of the Kikuchi Laboratory in Osaka University. When the university was founded in 1931, President Nagaoka put emphasis on the nuclear physics programs and called Professor Kikuchi to establish a center of nuclear physics. Since then the laboratory successfully cultivated the new field through studies of the neutron-nucleus interactions with a Cockcroft-Walton accelerator, the beta-decay study with a Cyclotron before the World-War II. Those accelerators were all home made, including the second cyclotron built after the war. Through such experimental programs, the Kikuchi Laboratory brought up many talented physicists in accelerator and nuclear science. (author)

  14. Torsion of a Wandering Spleen Presenting as Acute Abdomen

    International Nuclear Information System (INIS)

    Chauhan, Narvir Singh; Kumar, Satish

    2016-01-01

    Wandering spleen is a rare condition which if uncorrected, can result in torsion and infarction. Clinical presentation of a wandering spleen can vary from asymptomatic abdominal mass to acute abdominal pain. Radiological investigations play a pivotal role in diagnosis as the clinical diagnosis is usually impossible. We present a case of wandering spleen with torsion and complete infarction that occurred in a 32-year-old multiparous female. The diagnosis was established preoperatively on colour Doppler and CT of the abdomen with subsequent confirmation on surgery. Wandering spleen is a rare clinical condition which can present as acute abdomen. An increased awareness of this entity together with the timely use of ultrasound and CT of the abdomen can play an important role in preoperative diagnosis and surgical management

  15. Torsion of a wandering spleen | Carapinha | South African Journal of ...

    African Journals Online (AJOL)

    Abstract. Torsion of a wandering spleen is a rare and difficult diagnosis in the paediatric population, with death a possible outcome. In this paper we present our experience of a single case and discuss the embryology and management thereof.

  16. Detecting and Quantifying Mind Wandering during Simulated Driving

    Directory of Open Access Journals (Sweden)

    Carryl L. Baldwin

    2017-08-01

    Full Text Available Mind wandering is a pervasive threat to transportation safety, potentially accounting for a substantial number of crashes and fatalities. In the current study, mind wandering was induced through completion of the same task for 5 days, consisting of a 20-min monotonous freeway-driving scenario, a cognitive depletion task, and a repetition of the 20-min driving scenario driven in the reverse direction. Participants were periodically probed with auditory tones to self-report whether they were mind wandering or focused on the driving task. Self-reported mind wandering frequency was high, and did not statistically change over days of participation. For measures of driving performance, participant labeled periods of mind wandering were associated with reduced speed and reduced lane variability, in comparison to periods of on task performance. For measures of electrophysiology, periods of mind wandering were associated with increased power in the alpha band of the electroencephalogram (EEG, as well as a reduction in the magnitude of the P3a component of the event related potential (ERP in response to the auditory probe. Results support that mind wandering has an impact on driving performance and the associated change in driver’s attentional state is detectable in underlying brain physiology. Further, results suggest that detecting the internal cognitive state of humans is possible in a continuous task such as automobile driving. Identifying periods of likely mind wandering could serve as a useful research tool for assessment of driver attention, and could potentially lead to future in-vehicle safety countermeasures.

  17. Portal Venous Thrombosis Developing after Torsion of a Wandering ...

    African Journals Online (AJOL)

    2017-03-06

    Mar 6, 2017 ... L, Mullineris B, et al. Laparoscopic transperitoneal left adrenalectomy and wandering spleen risk. JSLS 2014:18-pii: e2014.00278. 5. Koca B, Çınar H, İA Tarım, Güngör BB. Torsion of the wandering spleen: A rare case of acute abdominal causing. Gulhane Med J 2013;55:51-53. 6. Herman TE, Siegel MJ.

  18. Patterns of aging in the long-lived wandering albatross.

    Science.gov (United States)

    Lecomte, Vincent Julien; Sorci, Gabriele; Cornet, Stéphane; Jaeger, Audrey; Faivre, Bruno; Arnoux, Emilie; Gaillard, Maria; Trouvé, Colette; Besson, Dominique; Chastel, Olivier; Weimerskirch, Henri

    2010-04-06

    How does an animal age in natural conditions? Given the multifaceted nature of senescence, identifying the effects of age on physiology and behavior remains challenging. We investigated the effects of age on a broad array of phenotypic traits in a wild, long-lived animal, the wandering albatross. We studied foraging behavior using satellite tracking and activity loggers in males and females (age 6-48+ years), and monitored reproductive performance and nine markers of baseline physiology known to reflect senescence in vertebrates (humoral immunity, oxidative stress, antioxidant defenses, and hormone levels). Age strongly affected foraging behavior and reproductive performance, but not baseline physiology. Consistent with results of mammal and human studies, age affected males and females differently. Overall, our findings demonstrate that age, sex, and foraging ability interact in shaping aging patterns in natural conditions. Specifically, we found an unexpected pattern of spatial segregation by age; old males foraged in remote Antarctica waters, whereas young and middle-aged males never foraged south of the Polar Front. Old males traveled a greater distance but were less active at the sea surface, and returned from sea with elevated levels of stress hormone (corticosterone), mirroring a low foraging efficiency. In contrast to findings in captive animals and short-lived birds, and consistent with disposable soma theory, we found no detectable age-related deterioration of baseline physiology in albatrosses. We propose that foraging efficiency (i.e., the ability of individuals to extract energy from their environment) might play a central role in shaping aging patterns in natural conditions.

  19. Toward a model-based cognitive neuroscience of mind wandering.

    Science.gov (United States)

    Hawkins, G E; Mittner, M; Boekel, W; Heathcote, A; Forstmann, B U

    2015-12-03

    People often "mind wander" during everyday tasks, temporarily losing track of time, place, or current task goals. In laboratory-based tasks, mind wandering is often associated with performance decrements in behavioral variables and changes in neural recordings. Such empirical associations provide descriptive accounts of mind wandering - how it affects ongoing task performance - but fail to provide true explanatory accounts - why it affects task performance. In this perspectives paper, we consider mind wandering as a neural state or process that affects the parameters of quantitative cognitive process models, which in turn affect observed behavioral performance. Our approach thus uses cognitive process models to bridge the explanatory divide between neural and behavioral data. We provide an overview of two general frameworks for developing a model-based cognitive neuroscience of mind wandering. The first approach uses neural data to segment observed performance into a discrete mixture of latent task-related and task-unrelated states, and the second regresses single-trial measures of neural activity onto structured trial-by-trial variation in the parameters of cognitive process models. We discuss the relative merits of the two approaches, and the research questions they can answer, and highlight that both approaches allow neural data to provide additional constraint on the parameters of cognitive models, which will lead to a more precise account of the effect of mind wandering on brain and behavior. We conclude by summarizing prospects for mind wandering as conceived within a model-based cognitive neuroscience framework, highlighting the opportunities for its continued study and the benefits that arise from using well-developed quantitative techniques to study abstract theoretical constructs. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. Polarization feedback laser stabilization

    Science.gov (United States)

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  1. The wandering spleen: CT findings and possible pitfalls in diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Ben Ely, A.; Zissin, R.; Copel, L.; Vasserman, M.; Hertz, M.; Gottlieb, P.; Gayer, G

    2006-11-15

    Aim: To report the CT features of wandering spleen, a rare condition which can be incidentally detected as an abdominal or pelvic mass or can present with torsion, causing an acute abdomen. Materials and methods: The CT studies of seven patients, two children and five adults, with wandering spleen were reviewed. CT was performed urgently in three patients for acute abdomen, and electively in four. Results: CT findings of wandering spleen included absence of the spleen in its normal position and a mass located elsewhere in the abdomen or pelvis, i.e. an ectopic spleen, enhancing homogeneously in four cases and failing partially or completely to enhance in the other three, indicating infarction. A 'whirl' appearance representing the twisted splenic pedicle was seen in the three cases with torsion. Urgent splenectomy confirmed infarction secondary to torsion. Conclusion: The possible diagnosis of wandering spleen should be kept in mind when CT shows the spleen to be absent from its usual position and a mass is found elsewhere in the abdomen or pelvis. When, in addition, a 'whirl' or partial or no enhancement of this mass are seen in a case presenting with acute abdomen, torsion of a wandering spleen is a likely diagnosis.

  2. Mind Wandering and Education: From the Classroom to Online Learning

    Directory of Open Access Journals (Sweden)

    Karl K Szpunar

    2013-08-01

    Full Text Available In recent years, cognitive and educational psychologists have become interested in applying principles of cognitive psychology to education. Here, we discuss the importance of understanding the nature and occurrence of mind wandering in the context of classroom and online lectures. In reviewing the relevant literature, we begin by considering early studies that provide important clues about student attentiveness via dependent measures such as physical markers of inattention, note taking, and retention. We then provide a broad overview of studies that have directly measured mind wandering in the classroom and online learning environments. Finally, we conclude by discussing interventions that might be effective at curbing the occurrence of mind wandering in educational settings, and consider various avenues of future research that we believe can shed light on this well-known but little studied phenomenon.

  3. Mind wandering and education: from the classroom to online learning.

    Science.gov (United States)

    Szpunar, Karl K; Moulton, Samuel T; Schacter, Daniel L

    2013-01-01

    In recent years, cognitive and educational psychologists have become interested in applying principles of cognitive psychology to education. Here, we discuss the importance of understanding the nature and occurrence of mind wandering in the context of classroom and online lectures. In reviewing the relevant literature, we begin by considering early studies that provide important clues about student attentiveness via dependent measures such as physical markers of inattention, note taking, and retention. We then provide a broad overview of studies that have directly measured mind wandering in the classroom and online learning environments. Finally, we conclude by discussing interventions that might be effective at curbing the occurrence of mind wandering in educational settings, and consider various avenues of future research that we believe can shed light on this well-known but little studied phenomenon.

  4. Controlling electron quantum paths for generation of circularly polarized high-order harmonics by H2+ subject to tailored (ω , 2 ω ) counter-rotating laser fields

    Science.gov (United States)

    Heslar, John; Telnov, Dmitry A.; Chu, Shih-I.

    2018-04-01

    Recently, studies of high-order harmonics (HHG) from atoms driven by bichromatic counter-rotating circularly polarized laser fields as a source of coherent circularly polarized extreme ultraviolet (XUV) and soft-x-ray beams in a tabletop-scale setup have received considerable attention. Here, we demonstrate the ability to control the electron recollisions giving three returns per one cycle of the fundamental frequency ω by using tailored bichromatic (ω , 2 ω ) counter-rotating circularly polarized laser fields with a molecular target. The full control of the electronic pathway is first analyzed by a classical trajectory analysis and then extended to a detailed quantum study of H2+ molecules in bichromatic (ω , 2 ω ) counter-rotating circularly polarized laser fields. The radiation spectrum contains doublets of left- and right-circularly polarized harmonics in the XUV ranges. We study in detail the below-, near-, and above-threshold harmonic regions and describe how excited-state resonances alter the ellipticity and phase of the generated harmonic peaks.

  5. Mind Wandering in Chinese Daily Lives – An Experience Sampling Study

    Science.gov (United States)

    Song, Xiaolan; Wang, Xiao

    2012-01-01

    Mind wandering has recently received extensive research because it reveals an important characteristic of our consciousness: conscious experience can arise internally and involuntarily. As the first attempt to examine mind wandering in a non-western population, the present study used experience-sampling method to collect the daily momentary mind wandering episodes in a Chinese sample. The results showed that mind wandering was also a ubiquitous experience among the Chinese population, and, instead of emerging out of nowhere, it was often elicited by external or internal cues. Furthermore, most of the mind wandering episodes involved prospective thinking and were closely related to one’s personal life. Finally, the frequency of mind wandering was influenced by some contextual factors. These results taken together suggest that mind wandering plays an important role in helping people to maintain a continuous feeling of “self” and to prepare them to cope with the upcoming events. PMID:22957071

  6. Mind wandering in Chinese daily lives--an experience sampling study.

    Directory of Open Access Journals (Sweden)

    Xiaolan Song

    Full Text Available Mind wandering has recently received extensive research because it reveals an important characteristic of our consciousness: conscious experience can arise internally and involuntarily. As the first attempt to examine mind wandering in a non-western population, the present study used experience-sampling method to collect the daily momentary mind wandering episodes in a Chinese sample. The results showed that mind wandering was also a ubiquitous experience among the Chinese population, and, instead of emerging out of nowhere, it was often elicited by external or internal cues. Furthermore, most of the mind wandering episodes involved prospective thinking and were closely related to one's personal life. Finally, the frequency of mind wandering was influenced by some contextual factors. These results taken together suggest that mind wandering plays an important role in helping people to maintain a continuous feeling of "self" and to prepare them to cope with the upcoming events.

  7. [Torsion of wandering spleen in a teenager: about a case].

    Science.gov (United States)

    Dème, Hamidou; Akpo, Léra Géraud; Fall, Seynabou; Badji, Nfally; Ka, Ibrahima; Guèye, Mohamadou Lamine; Touré, Mouhamed Hamine; Niang, El Hadj

    2016-01-01

    Wandering or migrating spleen is a rare anomaly which is usually described in children. Complications, which include pedicle torsion, are common and can be life-threatening. We report the case of a 17 year-old patient with a long past medical history of epigastric pain suffering from wandering spleen with chronic torsion of the pedicle. The clinical picture was marked by spontaneously painful epigastric mass, evolved over the past 48 hours. Abdominal ultrasound objectified heterogeneous hypertrophied ectopic spleen in epigastric position and a subcapsular hematoma. Doppler showed a torsion of splenic pedicle which was untwisted 2 turns and a small blood stream on the splenic artery. Abdominal CT scan with contrast injection showed a lack of parenchymal enhancement of large epigastric ectopic spleen and a subcapsular hematoma. The diagnosis of wandering spleen with chronic torsion of the pedicle complicated by necrosis and subcapsular hematoma was confirmed. The patient underwent splenectomy. The postoperative course was uneventful. We here discuss the contribution of ultrasound and CT scan in the diagnosis of wandering spleen with chronic torsion of the pedicle.

  8. Antibodies to Toxoplasma gondii in Backyard and Wandering Pigs ...

    African Journals Online (AJOL)

    The objective of this study was to investigate the occurrence of antibodies to Toxoplasma gondii in backyard and wandering pigs slaughtered for human consumption in Ibadan, Southwestern Nigeria. Serum samples were collected from 100 pigs and tested for the presence of IgG Toxoplasma gondii-specific antibodies ...

  9. People Mind Wander More during Massed than Spaced Inductive Learning

    Science.gov (United States)

    Metcalfe, Janet; Xu, Judy

    2016-01-01

    This article investigates the relation between mind wandering and the spacing effect in inductive learning. Participants studied works of art by different artists grouped in blocks, where works by a particular artist were either presented all together successively (the massed condition), or interleaved with the works of other artists (the spaced…

  10. Wandering spleen: Case report | Mwango | East African Medical ...

    African Journals Online (AJOL)

    Wandering spleens are rare clinical entities found more commonly in women aged 20-40 years. We report one such case found in a 24-year-old nulliparous woman who presented with low abdominal pains of sudden onset and splenomegaly. An emergency abdominal CT scan showed an enlarged spleen located in the ...

  11. Wandering Spleen with Splenic Vein Thrombosis: A Case Report ...

    African Journals Online (AJOL)

    A wandering spleen is a rare clinical occurrence with fewer than 500 cases reported and an incidence of less than 0.2%1, 2. The spleen is an important component of the reticuloendothelial system, which is involved in immunological defence and can serve as a storage site for red blood cells3. The spleen is normally ...

  12. Portal venous thrombosis developing after torsion of a wandering ...

    African Journals Online (AJOL)

    The etiological factors are the congenital absence of the ligaments that hold the spleen in its normal anatomic position, or the relaxation of these ligaments resulting from conditions like trauma and abdominal surgery. We aimed to present a rare case with torsion of wandering spleen that consequently developed thrombosis ...

  13. Reducing dementia related wandering behaviour with an interactive wall

    NARCIS (Netherlands)

    Robben, S.; Bergman, K.; Haitjema, S.; de Lange, Y.; Kröse, B.

    2012-01-01

    People suffering from dementia often have problems with way finding and feel restless. In this paper we present an interactive wall developed for decreasing the amount of wandering behaviour of people suffering from dementia. The installation aims at making these people feel more at home in the

  14. The wandering albatross Diomedea exulans is classified as ...

    African Journals Online (AJOL)

    spamer

    Since their establishment, all fledging chicks and adults .... at a rate of c. 5% per year (Nel et al. 2002c). During the late 1990s the population once again stabilized or started to decrease. Counts of birds breeding in the long-term study colonies ... 0.65. YEAR. Fig. 2: Mean number of chicks fledged per pair for wandering.

  15. A wandering spleen presenting as a hypogastric mass: Case report ...

    African Journals Online (AJOL)

    ... the spleen. A 26-year-old woman was admitted to our hospital with vomiting and abdominal pain. Abdominal examination revealed a large ovoid hypogastric mass. A CT scan showed a wandering spleen in the hypogastric region. Exploratory laparotomy revealed an ischemic spleen. A total splenectomy was performed.

  16. Towards operationalising internal distractibility (Mind Wandering) in adults with ADHD.

    Science.gov (United States)

    Biederman, Joseph; Fitzgerald, Maura; Uchida, Mai; Spencer, Thomas J; Fried, Ronna; Wicks, Jennifer; Saunders, Alexandra; Faraone, Stephen V

    2017-12-01

    To investigate whether specific symptoms of attention deficit hyperactivity disorder (ADHD) can help identify ADHD patients with mind wandering. Subjects were adults ages 18-55 of both sexes (n=41) who completed the Mind-Wandering Questionnaire (MWQ) and the ADHD module of the Schedule for Affective Disorders and Schizophrenia for School-Age Children Epidemiologic Version. We used Spearman's rank correlation and Pearson's χ2 analyses to examine associations between the ADHD module and the MWQ and receiver operator characteristic (ROC) analyses to evaluate the diagnostic efficiency of the ADHD module. Out of the three ADHD domains, the inattentive ADHD scores had the strongest association with the MWQ (total: r s=0.34, df=39, p=0.03; inattentive: r s=0.38, df=39, p=0.02; Hyperactive: r s=0.17, df=39, p=0.28). Correlation analyses between individual items on the ADHD module and the MWQ showed that two inattention items ('failure to pay attention to detail' and 'trouble following instructions') were positively associated with total scores on the MWQ (p=0.02). These two inattention items had the strongest association with the MWQ (r s=0.45, df=38, p=0.004). ROC analyses showed that the combined score of the two significant inattention items had the highest efficiency (AUC=0.71) in classifying high-level mind wanderers as defined by scores greater than the median split on the MWQ. The combined score of the two inattention items best identified high-level mind wanderers. Results suggest a way to operationalise mind wandering using the symptoms of ADHD.

  17. Understanding the role of mind wandering in stress-related working memory impairments.

    Science.gov (United States)

    Banks, Jonathan B; Boals, Adriel

    2017-08-01

    Mind wandering has been identified as a possible cause for stress-related working memory (WM) task impairments following laboratory stressors. The current study attempted to induce mind wandering regarding negative, positive, or neutral events using an expressive writing task and examined the impact on WM task performance. We examined the role of mind wandering in understanding the impact of life stress on WM. Additionally, we explored the role of thought suppression on the relationship between mind wandering and WM. One hundred and fifty participants completed WM measures before (Time 1) and after (Time 2) the writing manipulation. The writing manipulation did not alter mind wandering or WM task performance. Time 1 WM predicted mind wandering during the Time 2 WM task, which subsequently predicted poorer Time 2 WM task performance. The impact of daily life stress on WM was mediated by mind wandering. Trait levels of thought suppression moderated the impact of mind wandering on WM. Specifically, higher levels of suppression resulted in stronger negative impact of mind wandering on WM task performance. Findings are discussed in terms of the impact of mind wandering on WM task performance.

  18. Brief Mindfulness Meditation Training Reduces Mind-Wandering: The Critical Role of Acceptance

    Science.gov (United States)

    Rahl, Hayley A.; Lindsay, Emily K.; Pacilio, Laura E.; Brown, Kirk W.; Creswell, J. David

    2016-01-01

    Mindfulness meditation programs, which train individuals to monitor their present moment experience in an open or accepting way, have been shown to reduce mind-wandering on standardized tasks in several studies. Here we test two competing accounts for how mindfulness training reduces mind-wandering, evaluating whether the attention monitoring component of mindfulness training alone reduces mind-wandering or whether the acceptance training component is necessary for reducing mind-wandering. Healthy young adults (N=147) were randomized to either a 3-day brief mindfulness training condition incorporating instruction in both attention monitoring and acceptance, a mindfulness training condition incorporating attention monitoring instruction only, a relaxation training condition, or a reading control condition. Participants completed measures of dispositional mindfulness and treatment expectancies before the training session on Day 1 and then completed a 6-minute Sustained Attention Response Task (SART) measuring mind-wandering after the training session on Day 3. Acceptance training was important for reducing mind-wandering, such that the monitoring + acceptance mindfulness training condition had the lowest mind-wandering relative to the other conditions, including significantly lower mind-wandering relative to the monitor-only mindfulness training condition. In one of the first experimental mindfulness training dismantling studies to-date, we show that training in acceptance is a critical driver of mindfulness training reductions in mind-wandering. This effect suggests that acceptance skills may facilitate emotion regulation on boring and frustrating sustained attention tasks that foster mind-wandering, such as the SART. PMID:27819445

  19. Flight speed and performance of the wandering albatross with respect to wind.

    Science.gov (United States)

    Richardson, Philip L; Wakefield, Ewan D; Phillips, Richard A

    2018-01-01

    in headwind than tailwind flight but only in wind speeds of up to ~ 7 m/s. Our models predict that wandering albatrosses have oval-shaped airspeed polars, with the fastest airspeeds ~ 20 m/s centered in the across-wind direction. This suggests that in upwind flight in high winds, albatrosses can increase their ground speed by tacking like sailboats.

  20. A closer look at the relationship between the default network, mind wandering, negative mood, and depression.

    Science.gov (United States)

    Konjedi, Shaghayegh; Maleeh, Reza

    2017-08-01

    By a systematic analysis of the current literature on the neural correlates of mind wandering, that is, the default network (DN), and by shedding light on some determinative factors and conditions which affect the relationship between mind wandering and negative mood, we show that (1) mind wandering per se does not necessarily have a positive correlation with negative mood and, on the higher levels, depression. We propose that negative mood as a consequence of mind wandering generally depends on two determinative conditions, that is, whether mind wandering is with or without meta-awareness and whether mind wandering occurs during high or low vigilance states; (2) increased activity of the DN is not necessarily followed by an increase in unhappiness and depression. We argue that while in some kinds of meditation practices we witness an increase in the structure and in the activity of the DN, no increase in unhappiness and depression is observed.

  1. Gastric volvulus associated with wandering spleen in adult: Case report

    Directory of Open Access Journals (Sweden)

    Oktay Büyükaşık

    2012-07-01

    Full Text Available Gastric volvulus associated with wandering spleen is a rare diagnosis in adult ages. So far, only two cases have been reported in the literature. 82 year old male patients admitted to emergency department with complaint of nausea, vomiting and constipation. Physical examination and computerize tomography detected a big solid mass with regular contour which is full filling abdominal left lower quadrant. Exploratory laparotomy revealed a wandering spleen in sizes of 13x13x15 cm in the mentioned region. The spleen which had two masses on was partially ischemic. The stomach had rotated through cardiopyloric axis due to long pedicle of the spleen and adhesions neighborhood to corpoantral junction. Thus gastric passage was partialy obstructed. Splenectomy and anterior gastropexy were applied. The patient was discharged in health at 6th day postoperatively.

  2. Friedrich Nietzsche: the wandering and learned neuropath under Dionisius.

    Science.gov (United States)

    Gomes, Marleide da Mota

    2015-11-01

    Friedrich Nietzsche (1844-1900) was a remarkable philologist-philosopher while remaining in a condition of ill-health. Issues about his wandering/disruptive behavior that might be a consequence and/or protection against his cognitive decline and multifaceted disease are presented. The life complex that raises speculations about its etiology is constituted by: insight, creativity and wandering behavior besides several symptoms and signs of disease(s), mainly neurological one. The most important issue to be considered at the moment is not the disease diagnosis (Lissauer's general paresis or CADASIL, e.g.), but the probable Nietzsche's great cognitive reserve linked to the multifactorial etiology (genetic and environmental), and shared characteristics both to creativity and psychopathology. This makes any disease seems especial regarding Nietzsche, and whichever the diagnostic hypothesis has to consider the Nietzsche's unique background to express any disease(s).

  3. Friedrich Nietzsche: the wandering and learned neuropath under Dionisius

    Directory of Open Access Journals (Sweden)

    Marleide da Mota Gomes

    2015-01-01

    Full Text Available Friedrich Nietzsche (1844-1900 was a remarkable philologist-philosopher while remaining in a condition of ill-health. Issues about his wandering/disruptive behavior that might be a consequence and/or protection against his cognitive decline and multifaceted disease are presented. The life complex that raises speculations about its etiology is constituted by: insight, creativity and wandering behavior besides several symptoms and signs of disease(s, mainly neurological one. The most important issue to be considered at the moment is not the disease diagnosis (Lissauer’s general paresis or CADASIL, e.g., but the probable Nietzsche’s great cognitive reserve linked to the multifactorial etiology (genetic and environmental, and shared characteristics both to creativity and psychopathology. This makes any disease seems especial regarding Nietzsche, and whichever the diagnostic hypothesis has to consider the Nietzsche’s unique background to express any disease(s.

  4. Assessing the associations among trait and state levels of deliberate and spontaneous mind wandering.

    Science.gov (United States)

    Seli, Paul; Risko, Evan F; Smilek, Daniel

    2016-04-01

    Recent research has demonstrated that mind wandering can be subdivided into spontaneous and deliberate types, and this distinction has been found to hold at both the trait and state levels. However, to date, no attempts have been made to link trait-level spontaneous and deliberate mind wandering with state-level assessments of these two subtypes of mind wandering. Here we evaluated whether trait-level deliberate and spontaneous mind wandering map onto state levels of these subtypes of mind wandering. Results showed correspondence between trait-level reports of spontaneous and deliberate mind wandering and their state-level counterparts, indicating that people's reports on the intentionality of their mind wandering in the laboratory correspond to their reports of the intentionality of mind wandering in everyday life. Thus, the trait- and state-level scales of mind wandering were found to validate each other: Whereas the state-level measures provided some construct validity for the trait-level measures, the trait-level measures indicated that the state-level measures may be generalizable to everyday situations. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Linking mind wandering tendency to risky driving in young male drivers.

    Science.gov (United States)

    Albert, Derek A; Ouimet, Marie Claude; Jarret, Julien; Cloutier, Marie-Soleil; Paquette, Martin; Badeau, Nancy; Brown, Thomas G

    2018-02-01

    Risky driving is a significant contributor to road traffic crashes, especially in young drivers. Transient mind wandering states, an internal form of distraction, are associated with faster driving, reduced headway distance, slower response times, reduced driver vigilance, and increased crash risk. It is unclear whether a trait tendency to mind wander predicts risky driving, however. Mind wandering is also associated with poor executive control, but whether this capacity moderates the putative link between mind wandering tendency and risky driving is uncertain. The present study tested whether mind wandering tendency predicts risky driving behaviour in young male drivers aged 18-21 (N=30) and whether this relationship is mediated by driver vigilance and moderated by executive control capacity. Mind wandering was measured with the Sustained Attention to Response Task (SART) and the Daydreaming Frequency Scale (DDFS). Risky driving was assessed by mean speed in a driving simulator and driver vigilance was quantified by horizontal eye movements measured with eye tracking. Results showed that greater mind wandering tendency based on SART performance significantly predicts faster mean speed, confirming the main hypothesis. Neither driver vigilance mediated nor executive control capacity moderated this relationship as hypothesized. These findings speak to the complexity of individual differences in mind wandering. Overall, mind wandering tendency is a significant marker of risky driving in young drivers, which could guide the development of targeted interventions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Path Pascal

    Science.gov (United States)

    Campbell, R. H.; Kolstad, R. B.; Holle, D. F.; Miller, T. J.; Krause, P.; Horton, K.; Macke, T.

    1983-01-01

    Path Pascal is high-level experimental programming language based on PASCAL, which incorporates extensions for systems and real-time programming. Pascal is extended to treat real-time concurrent systems.

  7. Daydreaming Style Moderates the Relation between Working Memory and Mind Wandering: Integrating Two Hypotheses

    Science.gov (United States)

    Marcusson-Clavertz, David; Cardeña, Etzel; Terhune, Devin Blair

    2016-01-01

    Mind wandering--mentation unrelated to one's current activity and surroundings--is a ubiquitous phenomenon, but seemingly competing ideas have been proposed regarding its relation to executive cognitive processes. The control-failure hypothesis postulates that executive processes prevent mind wandering, whereas the global availability hypothesis…

  8. Students' Mind Wandering in Macroscopic and Submicroscopic Textual Narrations and Its Relationship with Their Reading Comprehension

    Science.gov (United States)

    Al-Balushi, Sulaiman M.; Al-Harthy, Ibrahim S.

    2015-01-01

    The aim of the current study was to investigate students' mind wandering while reading different types of textual narrations (macroscopic and submicroscopic) in chemistry. Another goal was to determine the relationship between mind wandering and students' reading comprehension. The participants were 65 female ninth grade students in Oman. Using a…

  9. Distracted by Your Mind? Individual Differences in Distractibility Predict Mind Wandering

    Science.gov (United States)

    Forster, Sophie; Lavie, Nilli

    2014-01-01

    Attention may be distracted from its intended focus both by stimuli in the external environment and by internally generated task-unrelated thoughts during mind wandering. However, previous attention research has focused almost exclusively on distraction by external stimuli, and the extent to which mind wandering relates to external distraction is…

  10. Cognitive and Contextual Correlates of Spontaneous and Deliberate Mind-Wandering

    Science.gov (United States)

    Robison, Matthew K.; Unsworth, Nash

    2018-01-01

    Individuals with greater cognitive abilities generally show reduced rates of mind-wandering when completing relatively demanding tasks (Randall, Oswald, & Beier, 2014). However, it is yet unclear whether elevated rates of mind-wandering among low-ability individuals are manifestations of deliberate, intentional episodes of mind-wandering…

  11. Functional connectivity within and between intrinsic brain networks correlates with trait mind wandering.

    Science.gov (United States)

    Godwin, Christine A; Hunter, Michael A; Bezdek, Matthew A; Lieberman, Gregory; Elkin-Frankston, Seth; Romero, Victoria L; Witkiewitz, Katie; Clark, Vincent P; Schumacher, Eric H

    2017-08-01

    Individual differences across a variety of cognitive processes are functionally associated with individual differences in intrinsic networks such as the default mode network (DMN). The extent to which these networks correlate or anticorrelate has been associated with performance in a variety of circumstances. Despite the established role of the DMN in mind wandering processes, little research has investigated how large-scale brain networks at rest relate to mind wandering tendencies outside the laboratory. Here we examine the extent to which the DMN, along with the dorsal attention network (DAN) and frontoparietal control network (FPCN) correlate with the tendency to mind wander in daily life. Participants completed the Mind Wandering Questionnaire and a 5-min resting state fMRI scan. In addition, participants completed measures of executive function, fluid intelligence, and creativity. We observed significant positive correlations between trait mind wandering and 1) increased DMN connectivity at rest and 2) increased connectivity between the DMN and FPCN at rest. Lastly, we found significant positive correlations between trait mind wandering and fluid intelligence (Ravens) and creativity (Remote Associates Task). We interpret these findings within the context of current theories of mind wandering and executive function and discuss the possibility that certain instances of mind wandering may not be inherently harmful. Due to the controversial nature of global signal regression (GSReg) in functional connectivity analyses, we performed our analyses with and without GSReg and contrast the results from each set of analyses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Transcranial direct current stimulation of the medial prefrontal cortex dampens mind-wandering in men.

    Science.gov (United States)

    Bertossi, Elena; Peccenini, Ludovica; Solmi, Andrea; Avenanti, Alessio; Ciaramelli, Elisa

    2017-12-05

    Mind-wandering, the mind's capacity to stray from external events and generate task-unrelated thought, has been associated with activity in the brain default network. To date, little is understood about the contribution of individual nodes of this network to mind-wandering. Here, we investigated the role of medial prefrontal cortex (mPFC) in mind-wandering, by perturbing this region with transcranial direct current stimulation (tDCS). Young healthy participants performed a choice reaction time task both before and after receiving cathodal tDCS over mPFC, and had their thoughts periodically sampled. We found that tDCS over mPFC - but not occipital or sham tDCS - decreased the propensity to mind-wander. The tDCS-induced reduction in mind-wandering occurred in men, but not in women, and was accompanied by a change in the content of task-unrelated though, which became more related to other people (as opposed to the self) following tDCS. These findings indicate that mPFC is crucial for mind-wandering, possibly by helping construction of self-relevant scenarios capable to divert attention inward, away from perceptual reality. Gender-related differences in tDCS-induced changes suggest that mPFC controls mind-wandering differently in men and women, which may depend on differences in the structural and functional organization of distributed brain networks governing mind-wandering, including mPFC.

  13. Self-Reported Stickiness of Mind-Wandering Affects Task Performance

    NARCIS (Netherlands)

    van Vugt, Marieke K; Broers, Nico

    2016-01-01

    When asked to perform a certain task, we typically spend a decent amount of time thinking thoughts unrelated to that task-a phenomenon referred to as "mind-wandering." It is thought that this mind-wandering is driven at least in part by our unfinished goals and concerns. Previous studies have shown

  14. Are you mind-wandering, or is your mind on task? The effect of probe framing on mind-wandering reports.

    Science.gov (United States)

    Weinstein, Yana; De Lima, Henry J; van der Zee, Tim

    2018-04-01

    The last decade has seen a dramatic rise in the number of studies that utilize the probe-caught method of collecting mind-wandering reports. This method involves stopping participants during a task, presenting them with a thought probe, and asking them to choose the appropriate report option to describe their thought-state. In this experiment we manipulated the framing of this probe, and demonstrated a substantial difference in mind-wandering reports as a function of whether the probe was presented in a mind-wandering frame compared with an on-task frame. This framing effect has implications both for interpretations of existing data and for methodological choices made by researchers who use the probe-caught mind-wandering paradigm.

  15. Thinking one thing, saying another: the behavioral correlates of mind-wandering while reading aloud.

    Science.gov (United States)

    Franklin, Michael S; Mooneyham, Benjamin W; Baird, Benjamin; Schooler, Jonathan W

    2014-02-01

    Although mind-wandering during silent reading is well documented, to date no research has investigated whether similar processes occur during reading aloud. In the present study, participants read a passage either silently or aloud while periodically being probed about mind-wandering. Although their comprehension accuracies were similar for both reading conditions, participants reported more mind-wandering while they were reading aloud. These episodes of mindless reading were associated with nearly normal prosody, but were nevertheless distinguished by subtle fluctuations in volume that were predictive of both overall comprehension accuracy and individual sentence comprehension. Together, these findings reveal that previously hidden within the common activity of reading aloud lies: (1) a demonstration of the remarkable automaticity of speech, (2) a situation that is surprisingly conducive to mind-wandering, (3) subtle vocal signatures of mind-wandering and comprehension accuracy, and (4) the promise of developing useful interventions to improve reading.

  16. Brief mindfulness meditation training reduces mind wandering: The critical role of acceptance.

    Science.gov (United States)

    Rahl, Hayley A; Lindsay, Emily K; Pacilio, Laura E; Brown, Kirk W; Creswell, J David

    2017-03-01

    Mindfulness meditation programs, which train individuals to monitor their present-moment experience in an open or accepting way, have been shown to reduce mind wandering on standardized tasks in several studies. Here we test 2 competing accounts for how mindfulness training reduces mind wandering, evaluating whether the attention-monitoring component of mindfulness training alone reduces mind wandering or whether the acceptance training component is necessary for reducing mind wandering. Healthy young adults (N = 147) were randomized to either a 3-day brief mindfulness training condition incorporating instruction in both attention monitoring and acceptance, a mindfulness training condition incorporating attention monitoring instruction only, a relaxation training condition, or an active reading-control condition. Participants completed measures of dispositional mindfulness and treatment expectancies before the training session on Day 1 and then completed a 6-min Sustained Attention to Response Task (SART) measuring mind wandering after the training session on Day 3. Acceptance training was important for reducing mind wandering, such that the attention-monitoring plus acceptance mindfulness training condition had the lowest mind wandering relative to the other conditions, including significantly lower mind wandering than the attention-monitoring only mindfulness training condition. In one of the first experimental mindfulness training dismantling studies to-date, we show that training in acceptance is a critical driver of mindfulness-training reductions in mind wandering. This effect suggests that acceptance skills may facilitate emotion regulation on boring and frustrating sustained attention tasks that foster mind wandering, such as the SART. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  17. Utterance paths

    NARCIS (Netherlands)

    Zhang, Lei; Hoede, C.

    2002-01-01

    In this paper the concept of utterance path is investigated. In the theory of knowledge graphs sentences are represented by socalled sentence graphs. The sentence graph of a sentence can be obtained by structural parsing of the sentence. Here we study the problem of determining rules for uttering

  18. Accessing Creativity: Jungian Night Sea Journeys, Wandering Minds, and Chaos.

    Science.gov (United States)

    Rosen, Diane

    2016-01-01

    NDS theory has been meaningfully applied to the dynamics of creativity and psychology. These complex systems have much in common, including a broad definition of "product" as new order emerging from disorder, a new whole (etymologically, 'health') out of disintegration or destabilization. From a nonlinear dynamical systems perspective, this paper explores the far-from-equilibrium zone of creative incubation: first in the Jungian night sea journey, a primordial myth of psychological and creative transformation; then in the neuroscience of mind wandering, the well-spring of creative ideation within the larger neural matrix. Finally, chaos theory grounds the elusive subject of creativity, modeling chaotic generation of idea elements that tend toward strange attractors, combine unpredictably, and produce change by means of tension between opposites, particularly notes consciousness (light) and the poetic unconscious (darkness). Examples from my own artwork illustrate this dialectical process. Considered together, the unconscious mythic sea journey, the unknowing wandering mind, and the generative paradigm of deterministic chaos suggest conditions that facilitate creativity across disciplines, providing fresh indications that the darkness of the unknown or irrational is, paradoxically, the illuminative source and strength of creativity.

  19. Reverse polarity magnetized melt rocks from the Chicxulub impact structure, Yucatan Peninsula, Mexico

    Science.gov (United States)

    Urrutia-Fucugauchi, Jaime; Marin, Luis E.; Sharpton, Virgil L.; Quezada, Juan Manuel

    1993-03-01

    Further paleomagnetic data for core samples of melt rock recovered in the Petroleos Mexicanos (PEMEX) exploratory wells within the Chicxulub structure, northern Yucatan peninsula, Mexico are reported. A previous report by Sharpton showed that the rocks studied contain high iridium levels and shocked breccia clasts, and an Ar-40/Ar-39 age of 65.2 plus or minus 0.4 Ma. The geomagnetic polarity determined for two samples is reverse (R) and was correlated with chron 29R that includes the K/T boundary. Our present analysis is based on two samples from each of three clasts of the melt rock from PEMEX well Y6-N17 (1295 to 1299 m b.s.l.). This study concentrates on the vectorial nature and stability of the remanence (NRM), the magnetic mineralogy and remanence carriers (i.e., the reliability and origin of the record), and on the implications (correlation with expected paleolatitude and polarity). The relative orientation of the drill core samples with respect to the horizontal is known. Samples were stable under alternating field (AF) and thermal treatments, and after removal of a small component they exhibited single-vectorial behavior. The characteristic remanence inclinations show small dispersion and a mean value (-43 deg) in close agreement with the expected inclination and paleolatitude (derived from the North American apparent polar wander path). Isothermal remenence (IRM) acquisition experiments, Lowrie-Fuller tests, coercivity and unblocking temperature spectra of NRM and saturation IRM, susceptibility and Q-coefficient analyses, and the single-component nature indicate a dominant mineralogy of iron-rich titanomagnetites with single or pseduo-single domain states. The stable characteristic magnetization may be interpreted as a result of shock heating of the rock at the time of formation of the inpact structure and its polarity, age, and paleolatitude are consistent with a time about the K/T boundary.

  20. Cognitive aging and the distinction between intentional and unintentional mind wandering.

    Science.gov (United States)

    Seli, Paul; Maillet, David; Smilek, Daniel; Oakman, Jonathan M; Schacter, Daniel L

    2017-06-01

    A growing number of studies have reported age-related reductions in the frequency of mind wandering. Here, at both the trait (Study 1) and state (Study 2) levels, we reexamined this association while distinguishing between intentional (deliberate) and unintentional (spontaneous) mind wandering. Based on research demonstrating age-accompanied deficits in executive functioning, we expected to observe increases in unintentional mind wandering with increasing age. Moreover, because aging is associated with increased task motivation, we reasoned that older adults might be more engaged in their tasks, and hence, show a more pronounced decline in intentional mind wandering relative to young adults. In both studies, we found that older adults did indeed report lower rates of intentional mind wandering compared with young adults. However, contrary to our expectations, we also found that older adults reported lower rates of unintentional mind wandering (Studies 1 and 2). We discuss the implications of these findings for theories of age-related declines in mind wandering. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  1. For Whom the Mind Wanders, and When, Varies Across Laboratory and Daily-Life Settings.

    Science.gov (United States)

    Kane, Michael J; Gross, Georgina M; Chun, Charlotte A; Smeekens, Bridget A; Meier, Matt E; Silvia, Paul J; Kwapil, Thomas R

    2017-09-01

    Undergraduates ( N = 274) participated in a weeklong daily-life experience-sampling study of mind wandering after being assessed in the lab for executive-control abilities (working memory capacity; attention-restraint ability; attention-constraint ability; and propensity for task-unrelated thoughts, or TUTs) and personality traits. Eight times a day, electronic devices prompted subjects to report on their current thoughts and context. Working memory capacity and attention abilities predicted subjects' TUT rates in the lab, but predicted the frequency of daily-life mind wandering only as a function of subjects' momentary attempts to concentrate. This pattern replicates prior daily-life findings but conflicts with laboratory findings. Results for personality factors also revealed different associations in the lab and daily life: Only neuroticism predicted TUT rate in the lab, but only openness predicted mind-wandering rate in daily life (both predicted the content of daily-life mind wandering). Cognitive and personality factors also predicted dimensions of everyday thought other than mind wandering, such as subjective judgments of controllability of thought. Mind wandering in people's daily environments and TUTs during controlled and artificial laboratory tasks have different correlates (and perhaps causes). Thus, mind-wandering theories based solely on lab phenomena may be incomplete.

  2. Daydream Believer: Rumination, Self-Reflection and the Temporal Focus of Mind Wandering Content.

    Science.gov (United States)

    Shrimpton, Daisy; McGann, Deborah; Riby, Leigh M

    2017-11-01

    Current research into mind-wandering is beginning to acknowledge that this process is one of heterogeneity. Following on from previous findings highlighting the role of self-focus during mind wandering, the present study aimed to examine individual differences in rumination and self-reflection and the impact such styles of self-focus may have on mind-wandering experiences. Thirty-three participants were required to complete the Sustained Attention Response Task (SART), aimed at inducing mind-wandering episodes, whilst also probing the content of thought in terms of temporal focus. Self-report questionnaires were also administered after the SART to measure dispositional differences in style and beliefs regarding mind-wandering and assessments of individual differences in rumination and self-reflection. Those individuals with reflective self-focus showed a strong positive association with positive and constructive thoughts. Critically, ruminative self-focus was positively associated with a tendency for the mind to wander towards anguished fantasies, failures and aggression, but it was also positively associated with positive and constructive thoughts. Furthermore, while dispositional differences in self-focus showed no relationship with the temporal perspective of thoughts when probed during a cognitive task, performance on the task itself was related to whether participants were thinking about the past, present or future during that activity. Such findings are discussed in line with previous research, and provide a further step towards accounting for the heterogeneous nature of mind-wandering.

  3. Path Creation

    DEFF Research Database (Denmark)

    Karnøe, Peter; Garud, Raghu

    2012-01-01

    This paper employs path creation as a lens to follow the emergence of the Danish wind turbine cluster. Supplier competencies, regulations, user preferences and a market for wind power did not pre-exist; all had to emerge in a tranformative manner involving multiple actors and artefacts. Competenc......This paper employs path creation as a lens to follow the emergence of the Danish wind turbine cluster. Supplier competencies, regulations, user preferences and a market for wind power did not pre-exist; all had to emerge in a tranformative manner involving multiple actors and artefacts....... Competencies emerged through processes and mechanisms such as co-creation that implicated multiple learning processes. The process was not an orderly linear one as emergent contingencies influenced the learning processes. An implication is that public policy to catalyse clusters cannot be based...

  4. A combined experimental and individual-differences investigation into mind wandering during a video lecture.

    Science.gov (United States)

    Kane, Michael J; Smeekens, Bridget A; von Bastian, Claudia C; Lurquin, John H; Carruth, Nicholas P; Miyake, Akira

    2017-11-01

    A combined experimental-correlational study with a diverse sample (N = 182) from 2 research sites tested a set of 5 a priori hypotheses about mind wandering and learning, using a realistic video lecture on introductory statistics. Specifically, the study examined whether students' vulnerability to mind wandering during the lecture would predict learning from, and situational interest in, the video and also whether longhand note-taking would help reduce mind wandering, at least for some students. One half of the participants took notes during the video, and all were subsequently tested on lecture content without notes. Regression and mediation analyses indicated that (a) several individual-differences variables (e.g., pretest score, prior math interest, classroom media multitasking habits) uniquely predicted in-lecture mind wandering frequency; (b) although the note-taking manipulation did not reduce mind wandering at the group level, note-taking still reduced mind wandering for some individuals (i.e., those with lower prior knowledge and those who took notes of high quality and quantity); (c) mind wandering uniquely predicted both learning (posttest) and situational interest outcomes above and beyond all other individual-differences variables; (d) moreover, mind wandering significantly mediated the effects of several individual differences; and, finally, (e) not all types of mind wandering were problematic-in fact, off-task reflections about lecture-related topics positively predicted learning. These results, which were generally robust across the 2 sites, suggest that educationally focused cognitive research may benefit from considering attentional processes during learning as well as cognitive and noncognitive individual differences that affect attention and learning. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. ECG baseline wander correction based on mean-median filter and empirical mode decomposition.

    Science.gov (United States)

    Xin, Yi; Chen, Yu; Hao, Wei Tuo

    2014-01-01

    A novel approach of ECG baseline wander correction based on mean-median filter and empirical mode decomposition is presented in this paper. The low frequency parts of the original signals were removed by the mean median filter in a nonlinear way to obtain the baseline wander estimation, then its series of IMFs were sifted by t-test after empirical mode decomposition. The proposed method, tested by the ECG signals in MIT-BIH Arrhythmia database and European ST_T database, is more effective compared with other baseline wander removal methods.

  6. Utterance paths

    OpenAIRE

    Zhang, Lei; Hoede, C.

    2002-01-01

    In this paper the concept of utterance path is investigated. In the theory of knowledge graphs sentences are represented by socalled sentence graphs. The sentence graph of a sentence can be obtained by structural parsing of the sentence. Here we study the problem of determining rules for uttering the sentence graph. Given a sentence graph there are usually several ways how such a graph can be brought under words, i.e. can be uttered. The sentences arising from these ways of uttering consist o...

  7. Turbulence-induced persistence in laser beam wandering.

    Science.gov (United States)

    Zunino, Luciano; Gulich, Damián; Funes, Gustavo; Pérez, Darío G

    2015-07-01

    We have experimentally confirmed the presence of long-memory correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. A laboratory-controlled experiment was conducted in which coordinate fluctuations of the laser beam were recorded at a sufficiently high sampling rate for a wide range of turbulent conditions. Horizontal and vertical displacements of the laser beam centroid were subsequently analyzed by implementing detrended fluctuation analysis. This is a very well-known and widely used methodology to unveil memory effects from time series. Results obtained from this experimental analysis allow us to confirm that both coordinates behave as highly persistent signals for strong turbulent intensities. This finding is relevant for a better comprehension and modeling of the turbulence effects in free-space optical communication systems and other applications related to propagation of optical signals in the atmosphere.

  8. Wandering tales: evolutionary origins of mental time travel and language

    Science.gov (United States)

    Corballis, Michael C.

    2013-01-01

    A central component of mind wandering is mental time travel, the calling to mind of remembered past events and of imagined future ones. Mental time travel may also be critical to the evolution of language, which enables us to communicate about the non-present, sharing memories, plans, and ideas. Mental time travel is indexed in humans by hippocampal activity, and studies also suggest that the hippocampus in rats is active when the animals replay or pre play activity in a spatial environment, such as a maze. Mental time travel may have ancient origins, contrary to the view that it is unique to humans. Since mental time travel is also thought to underlie language, these findings suggest that language evolved gradually from pre-existing cognitive capacities, contrary to the view of Chomsky and others that language and symbolic thought emerged abruptly, in a single step, within the past 100,000 years. PMID:23908641

  9. Wandering Tales: Evolutionary origins of mental time travel and language

    Directory of Open Access Journals (Sweden)

    Michael Charles Corballis

    2013-07-01

    Full Text Available A central component of mind wandering is mental time travel, the calling to mind of remembered past events and of imagined future ones. Mental time travel may also be critical to the evolution of language, which enables us to communicate about the nonpresent, sharing memories, plans, and ideas. Mental time travel is indexed in humans by hippocampal activity, and studies also suggest that the hippocampus in rats is active when the animals replay or pre play activity in a spatial environment, such as a maze. Mental time travel may have ancient origins, contrary to the view that it is unique to humans. Since mental time travel is also thought to underlie language, these findings suggest that language evolved gradually from pre-existing cognitive capacities, contrary to the view of Chomsky and others that language and symbolic thought emerged abruptly, in a single step, within the past 100,000 years.

  10. Age-related mate choice in the wandering albatross.

    Science.gov (United States)

    Jouventin; Lequette; Dobson

    1999-05-01

    We studied mate choice in the wandering albatross, Diomedea exulans, using data from 32 years of banding returns in the population of the Crozet Islands. We studied mating choices in a single year, when the Crozet Islands population was male biased (8:5, males:females). Thus, we expected that females might show great flexibility of choice of partners. Because age and experience might influence mate choice, we tested the expectation that females would choose the oldest and most experienced males for pair bonding. Pair bonds usually last until one member of the pair dies (0.3% of the birds 'divorce'), so mate choice should be especially important. We found that the ages of males and females in both displaying and bonded (breeding) pairs were significantly correlated. These age-associated pairings were not a passive phenomenon, but appeared to be due to an active process of selection of mates of similar age. First-time breeders sought mates of similar age, but preferred those with the most experience. Remating, experienced birds whose mates had died did not pair with individuals of significantly similar age, but predominantly paired with other widowed birds that, on average, were also relatively old. Mate fidelity in wandering albatrosses may be due to the cost of finding and bonding with a new mate. Pair bonds, and thus breeding, took an average of 3.2 and 2.3 years to establish, for males and females, respectively. Thus, remating exerts a potential average reproductive cost of about 15% of lifetime reproductive success. Copyright 1999 The Association for the Study of Animal Behaviour.

  11. Evidence for olfactory search in wandering albatross, Diomedea exulans.

    Science.gov (United States)

    Nevitt, Gabrielle A; Losekoot, Marcel; Weimerskirch, Henri

    2008-03-25

    Wandering albatrosses (Diomedea exulans) forage over thousands of square kilometers of open ocean for patchily distributed live prey and carrion. These birds have large olfactory bulbs and respond to fishy-scented odors in at-sea trials, suggesting that olfaction plays a role in natural foraging behavior. With the advent of new, fine-scale tracking technologies, we are beginning to explore how birds track prey in the pelagic environment, and we relate these observations to models of odor transport in natural situations. These models suggest that odors emanating from prey will tend to disperse laterally and downwind of the odor source and acquire an irregular and patchy concentration distribution due to turbulent transport. For a seabird foraging over the ocean, this scenario suggests that olfactory search would be facilitated by crosswind flight to optimize the probability of encountering a plume emanating from a prey item, followed by upwind, zigzag flight to localize the prey. By contrast, birds approaching prey by sight would be expected to fly directly to a prey item, irrespective of wind direction. Using high-precision global positioning system (GPS) loggers in conjunction with stomach temperature recorders to simultaneously monitor feeding events, we confirm these predictions in freely ranging wandering albatrosses. We found that initial olfactory detection was implicated in nearly half (46.8%) of all flown approaches preceding prey-capture events, accounting for 45.5% of total prey mass captured by in-flight foraging. These results offer insights into the sensory basis for area-restricted search at the large spatial scales of the open ocean.

  12. Beam wander relieved orbital angular momentum communication in turbulent atmosphere using Bessel beams.

    Science.gov (United States)

    Yuan, Yangsheng; Lei, Ting; Li, Zhaohui; Li, Yangjin; Gao, Shecheng; Xie, Zhenwei; Yuan, Xiaocong

    2017-02-10

    Optical beam wander is one of the most important issues for free-space optical (FSO) communication. We theoretically derive a beam wander model for Bessel beams propagating in turbulent atmosphere. The calculated beam wander of high order Bessel beams with different turbulence strengths are consistent with experimental measurements. Both theoretical and experimental results reveal that high order Bessel beams are less influenced by the turbulent atmosphere. We also demonstrate the Bessel beams based orbital angular momentum (OAM) multiplexing/demultiplexing in FSO communication with atmospheric turbulence. Under the same atmospheric turbulence condition, the bit error rates of transmitted signals carried by high order Bessel beams show smaller values and fluctuations, which indicates that the high order Bessel beams have an advantage of mitigating the beam wander in OAM multiplexing FSO communication.

  13. The Wandering Rash..... An unusual case of Benign Migratory Glossitis that healed with anti fungal treatment

    Directory of Open Access Journals (Sweden)

    Freny Karjodkar

    2004-01-01

    Full Text Available Benign migratory glossitis, also named as Geographic tongue, Wandering rash of tongue, Glossitis Areata Exfoliativa, Erythema migrans is a lesion of unknown etiology and is usually asymptomatic.

  14. Fluorescence confocal polarizing microscopy

    Indian Academy of Sciences (India)

    Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director patterns by ...

  15. Mind-wandering, cognition, and performance: a theory-driven meta-analysis of attention regulation.

    Science.gov (United States)

    Randall, Jason G; Oswald, Frederick L; Beier, Margaret E

    2014-11-01

    The current meta-analysis accumulates empirical findings on the phenomenon of mind-wandering, integrating and interpreting findings in light of psychological theories of cognitive resource allocation. Cognitive resource theory emphasizes both individual differences in attentional resources and task demands together to predict variance in task performance. This theory motivated our conceptual and meta-analysis framework by introducing moderators indicative of task-demand to predict who is more likely to mind-wander under what conditions, and to predict when mind-wandering and task-related thought are more (or less) predictive of task performance. Predictions were tested via a random-effects meta-analysis of correlations obtained from normal adult samples (k = 88) based on measurement of specified episodes of off-task and/or on-task thought frequency and task performance. Results demonstrated that people with fewer cognitive resources tend to engage in more mind-wandering, whereas those with more cognitive resources are more likely to engage in task-related thought. Addressing predictions of resource theory, we found that greater time-on-task-although not greater task complexity-tended to strengthen the negative relation between cognitive resources and mind-wandering. Additionally, increases in mind-wandering were generally associated with decreases in task performance, whereas increases in task-related thought were associated with increased performance. Further supporting resource theory, the negative relation between mind-wandering and performance was more pronounced for more complex tasks, though not longer tasks. Complementarily, the positive association between task-related thought and performance was stronger for more complex tasks and for longer tasks. We conclude by discussing implications and future research directions for mind-wandering as a construct of interest in psychological research. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  16. The influence of time on task on mind wandering and visual working memory.

    Science.gov (United States)

    Krimsky, Marissa; Forster, Daniel E; Llabre, Maria M; Jha, Amishi P

    2017-12-01

    Working memory relies on executive resources for successful task performance, with higher demands necessitating greater resource engagement. In addition to mnemonic demands, prior studies suggest that internal sources of distraction, such as mind wandering (i.e., having off-task thoughts) and greater time on task, may tax executive resources. Herein, the consequences of mnemonic demand, mind wandering, and time on task were investigated during a visual working memory task. Participants (N=143) completed a delayed-recognition visual working memory task, with mnemonic load for visual objects manipulated across trials (1 item=low load; 2 items=high load) and subjective mind wandering assessed intermittently throughout the experiment using a self-report Likert-type scale (1=on-task, 6=off-task). Task performance (correct/incorrect response) and self-reported mind wandering data were evaluated by hierarchical linear modeling to track trial-by-trial fluctuations. Performance declined with greater time on task, and the rate of decline was steeper for high vs low load trials. Self-reported mind wandering increased over time, and significantly varied asa function of both load and time on task. Participants reported greater mind wandering at the beginning of the experiment for low vs. high load trials; however, with greater time on task, more mind wandering was reported during high vs. low load trials. These results suggest that the availability of executive resources in support of working memory maintenance processes fluctuates in a demand-sensitive manner with time on task, and may be commandeered by mind wandering. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Taming a wandering attention: short-form mindfulness training in student cohorts

    OpenAIRE

    Morrison, Alexandra B.; Goolsarran, Merissa; Rogers, Scott L.; Jha, Amishi P.

    2014-01-01

    Mindfulness training (MT) is a form of mental training in which individuals engage in exercises to cultivate an attentive, present centered, and non-reactive mental mode. The present study examines the putative benefits of MT in University students for whom mind wandering can interfere with learning and academic success. We tested the hypothesis that short-form MT (7 h over 7 weeks) contextualized for the challenges and concerns of University students may reduce mind wandering and improve wor...

  18. Single-Incision Laparoscopic Splenectomy and Splenic Autotransplantation for an Enlarged Wandering Spleen with Torsion

    OpenAIRE

    Katsura, Shunsaku; Kawamura, Daichi; Harada, Eijiro; Enoki, Tadahiko; Hamano, Kimikazu

    2013-01-01

    A wandering spleen is a rare condition in which the spleen is not located in the left upper quadrant, but instead is found in the lower abdomen or in the pelvic region because of the laxity of the peritoneal attachments. The unusually long pedicle is susceptible to twisting, which can lead to ischemia, and eventually to necrosis. We herein report a case of an enlarged wandering spleen with torsion, successfully treated by single-incision laparoscopic splenectomy and autotransplantation. The t...

  19. The way we encounter reading material influences how frequently we mind wander

    OpenAIRE

    Trish L Varao Sousa; Jonathan S A Carriere; Dan eSmilek

    2013-01-01

    We examined whether different encounters of reading material influence the likelihood of mind wandering, memory for the material, and the ratings of interest in the material. In a within-subjects design participants experienced three different reading encounters: (1) reading a passage aloud, (2) listening to a passage being read to them, and (3) reading a passage silently. Throughout each reading encounter probes were given in order to identify mind wandering. After finishing the passage part...

  20. Attentional disengagements in educational contexts: a diary investigation of everyday mind-wandering and distraction

    OpenAIRE

    Unsworth, Nash; McMillan, Brittany D.

    2017-01-01

    The present study examined everyday attentional disengagements in educational contexts. Undergraduate students completed various cognitive ability measures in the laboratory and recorded everyday mind-wandering and distraction in a diary over the course of a week. Participants reported mind-wandering and being distracted both in class and while studying and there were a number of different subtypes of attentional disengagements. Individual differences in cognitive abilities were related to so...

  1. How to prevent mind-wandering during an EVA ? Presentation of a mind-wandering detection method using ECG technology in a Mars-analog environment

    Science.gov (United States)

    Gontier, Camille

    2017-11-01

    The purpose of this study is to detect mind-wandering in an Extra-Vehicular Activity (EVA) context during a long supervision task. Detection is realized using an electro-cardiogram and measures of heart rate variability. Experienced by everyone, mind-wandering depicts the state of mind where thoughts are not related to the current action. Its deleterious aspect regarding performance suggests a need to take mind-wandering seriously as an impediment to manned space missions' safety. Previous research confirmed the hypothesis according to which several physiological responses can be used to track down mind-wandering. ECG recordings are both easy to obtain and analyze, statistically related to mind-wandering, and easy to record during extra-vehicular activities. Data analyzed in this paper have been recorded during a Mars-analog mission (MDRS 164), from February 20 to March 6, 2016 at the Mars Desert Research Station (Utah). During various cognitive tasks, the subject had his ECG and awareness levels monitored at the same time to see if a correlation between these two measures can be used in a Mars-mission environment. At different time intervals, the subject was interrupted using the thought probe method to inquire about his thoughts. Heart Rate Variability (HRV, which power in high frequencies is related to the parasympathetic system and is expected to vary with mind-wandering) was then computed from recorded data, and its statistical changes during on-task and off-task thoughts were assessed. Although data revealed no significant differences nor coherent trends in HRV-related metrics between the two conditions, results are paving the way towards a better understanding of ECG-recordings and their use during space-analog missions.

  2. Language facilitates introspection: Verbal mind-wandering has privileged access to consciousness.

    Science.gov (United States)

    Bastian, Mikaël; Lerique, Sébastien; Adam, Vincent; Franklin, Michael S; Schooler, Jonathan W; Sackur, Jérôme

    2017-03-01

    Introspection and language are the cognitive prides of humankind, but their interactions in healthy cognition remain unclear. Episodes of mind-wandering, where personal thoughts often go unnoticed for some time before being introspected, offer a unique opportunity to study the role of language in introspection. In this paper, we show that inner speech facilitates awareness of mind-wandering. In two experiments, we either interfered with verbal working memory, via articulatory suppression (Exp. 1), or entrained it, via presentation of verbal material (Exp. 2), and measured the resulting awareness of mind-wandering. Articulatory suppression decreased the likelihood to spontaneously notice mind-wandering, whereas verbal material increased retrospective awareness of mind-wandering. In addition, an ecological study using smartphones confirmed that inner speech vividness positively predicted mind-wandering awareness (Exp. 3). Together, these findings support the view that inner speech facilitates introspection of one's thoughts, and therefore provides empirical evidence for a positive relation between language and consciousness. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. The way we encounter reading material influences how frequently we mind wander

    Science.gov (United States)

    Varao Sousa, Trish L.; Carriere, Jonathan S. A.; Smilek, Daniel

    2013-01-01

    We examined whether different encounters of reading material influence the likelihood of mind wandering, memory for the material, and the ratings of interest in the material. In a within-subjects design participants experienced three different reading encounters: (1) reading a passage aloud, (2) listening to a passage being read to them, and (3) reading a passage silently. Throughout each reading encounter probes were given in order to identify mind wandering. After finishing the passage participants also rated how interesting it was and completed a content recognition test. Results showed that reading aloud led to the least amount of mind wandering, while listening to the passage led to the most mind wandering. Listening to the passage was also associated with the poorest memory performance and the least interest in the material. Finally, within the silent reading and listening encounters we observed negative relations between mind wandering and both memory performance and interest in the material, replicating previous findings. Taken together, the present findings improve our understanding of the nature of mind wandering while reading, and have potentially important implications for readers seeking to take advantage of the convenience of audiobooks and podcasts. PMID:24348444

  4. The role of the default mode network in component processes underlying the wandering mind.

    Science.gov (United States)

    Poerio, Giulia L; Sormaz, Mladen; Wang, Hao-Ting; Margulies, Daniel; Jefferies, Elizabeth; Smallwood, Jonathan

    2017-07-01

    Experiences such as mind-wandering illustrate that cognition is not always tethered to events in the here-and-now. Although converging evidence emphasises the default mode network (DMN) in mind-wandering, its precise contribution remains unclear. The DMN comprises cortical regions that are maximally distant from primary sensory and motor cortex, a topological location that may support the stimulus-independence of mind-wandering. The DMN is functionally heterogeneous, comprising regions engaged by memory, social cognition and planning; processes relevant to mind-wandering content. Our study examined the relationships between: (i) individual differences in resting-state DMN connectivity, (ii) performance on memory, social and planning tasks and (iii) variability in spontaneous thought, to investigate whether the DMN is critical to mind-wandering because it supports stimulus-independent cognition, memory retrieval, or both. Individual variation in task performance modulated the functional organization of the DMN: poor external engagement was linked to stronger coupling between medial and dorsal subsystems, while decoupling of the core from the cerebellum predicted reports of detailed memory retrieval. Both patterns predicted off-task future thoughts. Consistent with predictions from component process accounts of mind-wandering, our study suggests a 2-fold involvement of the DMN: (i) it supports experiences that are unrelated to the environment through strong coupling between its sub-systems; (ii) it allows memory representations to form the basis of conscious experience. © The Author (2017). Published by Oxford University Press.

  5. Mindfulness and mind wandering: The protective effects of brief meditation in anxious individuals.

    Science.gov (United States)

    Xu, Mengran; Purdon, Christine; Seli, Paul; Smilek, Daniel

    2017-05-01

    Mind wandering can be costly, especially when we are engaged in attentionally demanding tasks. Preliminary studies suggest that mindfulness can be a promising antidote for mind wandering, albeit the evidence is mixed. To better understand the exact impact of mindfulness on mind wandering, we had a sample of highly anxious undergraduate students complete a sustained-attention task during which off-task thoughts including mind wandering were assessed. Participants were randomly assigned to a meditation or control condition, after which the sustained-attention task was repeated. In general, our results indicate that mindfulness training may only have protective effects on mind wandering for anxious individuals. Meditation prevented the increase of mind wandering over time and ameliorated performance disruption during off-task episodes. In addition, we found that the meditation intervention appeared to promote a switch of attentional focus from the internal to present-moment external world, suggesting important implications for treating worrying in anxious populations. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. The way we encounter reading material influences how frequently we mind wander

    Directory of Open Access Journals (Sweden)

    Trish L Varao Sousa

    2013-11-01

    Full Text Available We examined whether different encounters of reading material influence the likelihood of mind wandering, memory for the material, and the ratings of interest in the material. In a within-subjects design participants experienced three different reading encounters: 1 reading a passage aloud, 2 listening to a passage being read to them, and 3 reading a passage silently. Throughout each reading encounter probes were given in order to identify mind wandering. After finishing the passage participants also rated how interesting it was and completed a content recognition test. Results showed that reading aloud led to the least amount of mind wandering, while listening to the passage led to the most mind wandering. Listening to the passage was also associated with the poorest memory performance and the least interest in the material. Finally, within the silent reading and listening encounters we observed negative relations between mind wandering and both memory performance and interest in the material, replicating previous findings. Taken together, the present findings improve our understanding of the nature of mind wandering while reading, and have potentially important implications for readers seeking to take advantage of the convenience of audiobooks and podcasts.

  7. Reported Wandering Behavior among Children with Autism Spectrum Disorder and/or Intellectual Disability

    Science.gov (United States)

    Rice, Catherine E.; Zablotsky, Benjamin; Avila, Rosa M.; Colpe, Lisa J.; Schieve, Laura A.; Pringle, Beverly; Blumberg, Stephen J.

    2016-01-01

    Objective To characterize wandering, or elopement, among children with autism spectrum disorder (ASD) and intellectual disability. Study design Questions on wandering in the previous year were asked of parents of children with ASD with and without intellectual disability and children with intellectual disability without ASD as part of the 2011 Survey of Pathways to Diagnosis and Services. The Pathways study sample was drawn from the much larger National Survey of Children with Special Health Care Needs conducted in 2009-2010. Results For children with special healthcare needs diagnosed with either ASD, intellectual disability, or both, wandering or becoming lost during the previous year was reported for more than 1 in 4 children. Wandering was highest among children with ASD with intellectual disability (37.7%) followed by children with ASD without intellectual disability (32.7%), and then children with intellectual disability without ASD (23.7%), though the differences between these groups were not statistically significant. Conclusions This study affirms that wandering among children with ASD, regardless of intellectual disability status, is relatively common. However, wandering or becoming lost in the past year was also reported for many children with intellectual disability, indicating the need to broaden our understanding of this safety issue to other developmental disabilities. PMID:27157446

  8. Reported Wandering Behavior among Children with Autism Spectrum Disorder and/or Intellectual Disability.

    Science.gov (United States)

    Rice, Catherine E; Zablotsky, Benjamin; Avila, Rosa M; Colpe, Lisa J; Schieve, Laura A; Pringle, Beverly; Blumberg, Stephen J

    2016-07-01

    To characterize wandering, or elopement, among children with autism spectrum disorder (ASD) and intellectual disability. Questions on wandering in the previous year were asked of parents of children with ASD with and without intellectual disability and children with intellectual disability without ASD as part of the 2011 Survey of Pathways to Diagnosis and Services. The Pathways study sample was drawn from the much larger National Survey of Children with Special Health Care Needs conducted in 2009-2010. For children with special healthcare needs diagnosed with either ASD, intellectual disability, or both, wandering or becoming lost during the previous year was reported for more than 1 in 4 children. Wandering was highest among children with ASD with intellectual disability (37.7%) followed by children with ASD without intellectual disability (32.7%), and then children with intellectual disability without ASD (23.7%), though the differences between these groups were not statistically significant. This study affirms that wandering among children with ASD, regardless of intellectual disability status, is relatively common. However, wandering or becoming lost in the past year was also reported for many children with intellectual disability, indicating the need to broaden our understanding of this safety issue to other developmental disabilities. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Polarization Optics

    OpenAIRE

    Fressengeas, Nicolas

    2010-01-01

    The physics of polarization optics *Polarized light propagation *Partially polarized light; DEA; After a brief introduction to polarization optics, this lecture reviews the basic formalisms for dealing with it: Jones Calculus for totally polarized light and Stokes parameters associated to Mueller Calculus for partially polarized light.

  10. Mind wandering and reading comprehension: examining the roles of working memory capacity, interest, motivation, and topic experience.

    Science.gov (United States)

    Unsworth, Nash; McMillan, Brittany D

    2013-05-01

    Individual differences in mind wandering and reading comprehension were examined in the current study. In particular, individual differences in mind wandering, working memory capacity, interest in the current topic, motivation to do well on the task, and topic experience and their relations with reading comprehension were examined in the current study. Using confirmatory factor analysis and structural equation modeling it was found that variation in mind wandering while reading was influenced by working memory capacity, topic interest, and motivation. Furthermore, these same factors, along with topic experience, influenced individual differences in reading comprehension. Importantly, several factors had direct effects on reading comprehension (and mind wandering), while the relation between reading comprehension (and mind wandering) and other factors occurred via indirect effects. These results suggest that both domain-general and domain-specific factors contribute to mind wandering while reading and to reading comprehension.

  11. Mind Wandering in Text Comprehension under Dual-Task Conditions

    Directory of Open Access Journals (Sweden)

    Peter eDixon

    2013-10-01

    Full Text Available In two experiments, subjects responded to on-task probes while reading under dual-task conditions. The secondary task was to monitor the text for occurrences of the letter e. In Experiment 1, reading comprehension was assessed with a multiple-choice recognition test; in Experiment 2, subjects recalled the text. In both experiments, the secondary task replicated the well-known missing-letter effect in which detection of e’s was less effective for the word the. Letter detection was also more effective when subjects were on task, but this effect did not interact with the missing-letter effect. Comprehension was assessed in both the dual-task conditions and in a control single-task conditions. In the single-task conditions, both recognition (Experiment 1 and recall (Experiment 2 was better when subjects were on task, replicating previous research on mind wandering. Surprisingly, though, comprehension under dual-task conditions only showed an effect of being on task when measured with recall; there was no effect on recognition performance. Our interpretation of this pattern of results is that subjects generate their response to on-task probes on the basis of a retrospective assessment of the contents of working memory. Further, we argue that under dual-task conditions, the contents of working memory is not related to the reading processes required for accurate recognition performance. These conclusions have implications for models of text comprehension and for the interpretation of on-task probe responses.

  12. When attention wanders: Pupillometric signatures of fluctuations in external attention.

    Science.gov (United States)

    Konishi, Mahiko; Brown, Kevin; Battaglini, Luca; Smallwood, Jonathan

    2017-11-01

    Attention is not always directed to events in the external environment. On occasion our thoughts wander to people and places distant from the here and now. Sometimes, this lack of external attention can compromise ongoing task performance. In the current study we set out to understand the extent to which states of internal and external attention can be determined using pupillometry as an index of ongoing cognition. In two experiments we found that periods of slow responding were associated with elevations in the baseline pupil signal over three and a half seconds prior to a behavioural response. In the second experiment we found that unlike behavioural lapses, states of off-task thought, particularly those associated with a focus on the past and with an intrusive quality, were associated with reductions in the size of the pupil over the same window prior to the probe. These data show that both states of large and small baseline pupil size are linked to states when attention is not effectively focused on the external environment, although these states have different qualities. More generally, these findings illustrate that subjective and objective markers of task performance may not be equivalent and underscore the importance of developing objective indicators that can allow these different states to be understood. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Driven to distraction: A lack of change gives rise to mind wandering.

    Science.gov (United States)

    Faber, Myrthe; Radvansky, Gabriel A; D'Mello, Sidney K

    2018-04-01

    How does the dynamic structure of the external world direct attention? We examined the relationship between event structure and attention to test the hypothesis that narrative shifts (both theoretical and perceived) negatively predict attentional lapses. Self-caught instances of mind wandering were collected while 108 participants watched a 32.5 min film called The Red Balloon. We used theoretical codings of situational change and human perceptions of event boundaries to predict mind wandering in 5-s intervals. Our findings suggest a temporal alignment between the structural dynamics of the film and mind wandering reports. Specifically, the number of situational changes and likelihood of perceiving event boundaries in the prior 0-15 s interval negatively predicted mind wandering net of low-level audiovisual features. Thus, mind wandering is less likely to occur when there is more event change, suggesting that narrative shifts keep attention from drifting inwards. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Going AWOL in the brain: mind wandering reduces cortical analysis of external events.

    Science.gov (United States)

    Smallwood, Jonathan; Beach, Emily; Schooler, Jonathan W; Handy, Todd C

    2008-03-01

    Converging evidence from neuroscience suggests that our attention to the outside world waxes and wanes over time. We examined whether these periods of "mind wandering" are associated with reduced cortical analysis of the external environment. Participants performed a sustained attention to response task in which they responded to frequent "nontargets" (digits 0-9) and withheld responses for infrequent "targets" (the letter X). Mind wandering was defined both behaviorally, indicated by a failure to withhold a response to a target, and subjectively, via self-report at a thought probe. The P300 event-related potential component for nontargets was reduced prior to both the behavioral and subjective reports of mind wandering, relative to periods of being "on-task." Regression analysis of P300 amplitude revealed significant common variance between behavioral and subjective markers of mind wandering, suggesting that both markers reflect a common underlying mental state. Finally, control analysis revealed that the effect of mind wandering on the P300 could not be ascribed to changes in motor activity nor was it associated with general arousal. Our data suggest that when trying to engage attention in a sustained manner, the mind will naturally ebb and flow in the depth of cognitive analysis it applies to events in the external environment.

  15. Mind wandering via mental contrasting as a tool for behavior change

    Directory of Open Access Journals (Sweden)

    Gabriele eOettingen

    2013-09-01

    Full Text Available When people engage in mind wandering they drift away from a task towards their inner thoughts and feelings. These thoughts often circle around people’s personal futures. One assumed function of mind wandering is that it aids problem solving and planning for the future. We will discuss different forms of mind wandering and their effects on problem solving and behavior change. While solely fantasizing about a desired future leads to poor problem solving and little behavior change, mind wandering in the form of mental contrasting leads to skilled problem solving and substantial behavior change. In mental contrasting, people first envision the desired future and then imagine the obstacles that need to be surmounted to reach said future. Mental contrasting instigates behavior change by modulating the strength of associations between future and reality and between reality and instrumental action. Intervention research shows that mental contrasting can be taught as a cost- and time-effective self-regulation strategy of behavior change. The findings have implications for research on mind wandering, problem solving, and on creating effective interventions of behavior change.

  16. The Clinical Presentation and Outcome of the Institutionalized Wandering Mentally Ill in India.

    Science.gov (United States)

    Singh, Gaurav; Shah, Nilima; Mehta, Ritambhara

    2016-10-01

    There are estimated 400,000 wandering mentally ill persons in India, found in poor physical state wandering on streets and railway stations; mainly treated either by government run Hospitals for Mental Health (HMH) or Psychiatry units of a Government Medical College (GMC). They require psychosocial rehabilitation along with treatment. To study the presentation, clinical profile and rehabilitative outcome of wandering mentally ill admitted in government psychiatric care facilities. The objective was to establish them as a distinct psychiatric inpatient population requiring special attention. The study was a chart review of all wandering mentally ill patients institutionalized during a period of two years in two distinct government facilities. Additionally, clinical staff was interviewed for cross checking the data and for eliciting problems faced in management. The discharged patients were contacted to assess the present status. Forty seven patients in HMH and 35 patients in GMC were studied. Wandering mentally ill patients were brought to mental health facility by helping person (30) and police (23). Majority of them (61) were picked up from streets and railway station. Most of them (56) belonged to mentally ill constitutes a unique patient population with specific challenges different from other inpatients in management and rehabilitation. Provisions to take care of this most vulnerable group of the society and mechanisms to watch for their continuous implementation are required.

  17. Evidence for sex-segregated ocean distributions of first-winter wandering albatrosses at Crozet islands.

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    Susanne Åkesson

    Full Text Available The highly mobile wandering albatrosses (Diomedea exulans are adapted to navigate the extreme environment of the Southern Ocean and return to isolated islands to breed. Each year they cover several hundreds of thousands of kilometers during travels across the sea. Little is known about the dispersal flights and migration of young albatrosses. We tracked, by satellite telemetry, the departure dispersal of 13 juvenile wandering albatrosses from the Crozet Islands and compared them with tracks of 7 unrelated adults during the interbreeding season. We used the satellite tracks to identify different behavioural steps of the inherited migration program used by juvenile wandering albatrosses during their first solo-migration. Our results show that the juvenile wandering albatrosses from Crozet Islands moved to sex-specific foraging zones of the ocean using at departures selectively the wind. The results suggest that the inherited migration program used by the juvenile wandering albatrosses encode several distinct steps, based on inherited preferred departure routes, differences in migration distance between sexes, and selective use of winds. During long transportation flights the albatrosses were influenced by winds and both adult and juveniles followed approximate loxodrome (rhumbline routes coinciding with the foraging zone and the specific latitudes of their destination areas. During the long segments of transportation flights across open seas the juveniles selected routes at more northerly latitudes than adults.

  18. Does Mind Wandering Reflect Executive Function or Executive Failure? Comment on Smallwood and Schooler (2006) and Watkins (2008)

    Science.gov (United States)

    McVay, Jennifer C.; Kane, Michael J.

    2010-01-01

    In this comment, we contrast different conceptions of mind wandering that were presented in 2 recent theoretical reviews: Smallwood and Schooler (2006) and Watkins (2008). We also introduce a new perspective on the role of executive control in mind wandering by integrating empirical evidence presented in Smallwood and Schooler with 2 theoretical…

  19. Mind Wandering and Reading Comprehension: Examining the Roles of Working Memory Capacity, Interest, Motivation, and Topic Experience

    Science.gov (United States)

    Unsworth, Nash; McMillan, Brittany D.

    2013-01-01

    Individual differences in mind wandering and reading comprehension were examined in the current study. In particular, individual differences in mind wandering, working memory capacity, interest in the current topic, motivation to do well on the task, and topic experience and their relations with reading comprehension were examined in the current…

  20. When the Brain Takes a Break: A Model-Based Analysis of Mind Wandering

    Science.gov (United States)

    Boekel, Wouter; Tucker, Adrienne M.; Turner, Brandon M.; Heathcote, Andrew; Forstmann, Birte U.

    2014-01-01

    Mind wandering is an ubiquitous phenomenon in everyday life. In the cognitive neurosciences, mind wandering has been associated with several distinct neural processes, most notably increased activity in the default mode network (DMN), suppressed activity within the anti-correlated (task-positive) network (ACN), and changes in neuromodulation. By using an integrative multimodal approach combining machine-learning techniques with modeling of latent cognitive processes, we show that mind wandering in humans is characterized by inefficiencies in executive control (task-monitoring) processes. This failure is predicted by a single-trial signature of (co)activations in the DMN, ACN, and neuromodulation, and accompanied by a decreased rate of evidence accumulation and response thresholds in the cognitive model. PMID:25471568

  1. Revisiting the wandering womb: Oxytocin in endometriosis and bipolar disorder.

    Science.gov (United States)

    Dinsdale, Natalie L; Crespi, Bernard J

    2017-11-01

    Hippocrates attributed women's high emotionality - hysteria - to a 'wandering womb'. Although hysteria diagnoses were abandoned along with the notion that displaced wombs cause emotional disturbance, recent research suggests that elevated levels of oxytocin occur in both bipolar disorder and endometriosis, a gynecological condition involving migration of endometrial tissue beyond the uterus. We propose and evaluate the hypothesis that elevated oxytocinergic system activity jointly contributes to bipolar disorder and endometriosis. First, we provide relevant background on endometriosis and bipolar disorder, and then we examine evidence for comorbidity between these conditions. We next: (1) review oxytocin's associations with personality traits, especially extraversion and openness, and how they overlap with bipolar spectrum traits; (2) describe evidence for higher oxytocinergic activity in both endometriosis and bipolar disorder; (3) examine altered hypothalamic-pituitary-gonadal axis functioning in both conditions; (4) describe data showing that medications that treat one condition can improve symptoms of the other; (5) discuss fitness-related impacts of endometriosis and bipolar disorder; and (6) review a pair of conditions, polycystic ovary syndrome and autism, that show evidence of involving reduced oxytocinergic activity, in direct contrast to endometriosis and bipolar disorder. Considered together, the bipolar spectrum and endometriosis appear to involve dysregulated high extremes of normally adaptive pleiotropy in the female oxytocin system, whereby elevated levels of oxytocinergic activity coordinate outgoing sociality with heightened fertility, apparently characterizing, overall, a faster life history. These findings should prompt a re-examination of how mind-body interactions, and the pleiotropic endocrine systems that underlie them, contribute to health and disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Behavioral responses to encounter of fishing boats in wandering albatrosses.

    Science.gov (United States)

    Collet, Julien; Patrick, Samantha C; Weimerskirch, Henri

    2017-05-01

    Animals are attracted to human food subsidies worldwide. The behavioral response of individuals to these resources is rarely described in detail, beyond chances of encounters. Seabirds for instance scavenge in large numbers at fishing boats, triggering crucial conservation issues, but how the response to boats varies across encounters is poorly known. Here we examine the behavioral response of wandering albatrosses ( Diomedea exulans ), equipped with GPS tags, to longline fishing boats operating near their colony for which we had access to vessel monitoring system data. We distinguish between encounters (flying within 30 km of a boat) and attendance behavior (sitting on the sea within 3 km of a boat), and examine factors affecting each. In particular, we test hypotheses that the response to encountered boats should vary with sex and age in this long-lived dimorphic species. Among the 60% trips that encountered boats at least once, 80% of them contained attendance (but attendance followed only 60% of each single encounter). Birds were more attracted and remained attending longer when boats were hauling lines, despite the measures enforced by this fleet to limit food availability during operations. Sex and age of birds had low influence on the response to boats, except the year when fewer boats came fishing in the area, and younger birds were attending further from boats compared to older birds. Net mass gain of birds was similar across sex and not affected by time spent attending boats. Our results indicate albatrosses extensively attend this fishery, with no clear advantages, questioning impacts on foraging time budgets. Factors responsible for sex foraging segregation at larger scale seem not to operate at this fleet near the colony and are not consistent with predictions of optimal foraging theory on potential individual dominance asymmetries. This approach complements studies of large-scale overlap of animals with human subsidies.

  3. Intentionality and meta-awareness of mind wandering: Are they one and the same, or distinct dimensions?

    Science.gov (United States)

    Seli, Paul; Ralph, Brandon C W; Risko, Evan F; W Schooler, Jonathan; Schacter, Daniel L; Smilek, Daniel

    2017-12-01

    Researchers have recently demonstrated that mind-wandering episodes can vary on numerous dimensions, and it has been suggested that assessing these dimensions will play an important role in our understanding of mind wandering. One dimension that has received considerable attention in recent work is the intentionality of mind wandering. Although it has been claimed that indexing the intentionality of mind wandering will be necessary if researchers are to obtain a coherent understanding of the wandering mind, one concern is that this dimension might be redundant with another, longstanding, dimension: namely, meta-awareness. Thus, the utility of the argument for assessing intentionality rests upon a demonstration that this dimension is distinct from the meta-awareness dimension. To shed light on this issue, across two studies we compared and contrasted these dimensions to determine whether they are redundant or distinct. In both studies, we found support for the view that these dimensions are distinct.

  4. In pursuit of off-task thought: mind wandering-performance trade-offs while reading aloud and color naming

    Science.gov (United States)

    Thomson, David R.; Besner, Derek; Smilek, Daniel

    2013-01-01

    The present study investigated whether the frequency of probe-caught mind wandering varied by condition and had any impact on performance in both an item-by-item reading aloud task and a blocked version of the classic Stroop task. Across both experiments, mind wandering rates were found to be quite high and were negatively associated with vocal onset latencies and error rates across conditions. Despite this however, we observed poor correspondence between the effects of task demands on mind wandering rates and the effects of mind wandering on primary task performance. We discuss these findings in relation to attentional resource accounts of mind wandering and suggest that individuals can adjust the relative distribution of executive/attentional resources between internal and external goals in a way that maximizes off-task thought while preserving primary task performance. PMID:23785351

  5. A Platform for e-Health Control and Location Services for Wandering Patients

    Directory of Open Access Journals (Sweden)

    Samantha Yasivee Carrizales-Villagómez

    2018-01-01

    Full Text Available Wandering patients frequently have diseases that demand continuous health control, such as taking pills at specific times, constant blood pressure and heart rate monitoring, temperature and stress level checkups, and so on. These could be jeopardized by their wandering behavior. Mobile applications that focus on health care have received special interest from medical specialists. These applications have been widely accepted, due to the availability of smart devices that include sensors. However, sensor-based applications are highly energy demanding and as such, they can be unaffordable in mobile e-health control due to battery constraints. This paper presents the design and implementation of a platform aimed at providing support in e-health control and provision of location services for wandering patients through real-time medical and mobility information analysis. The platform includes a configurable mobile application for heart rate and stress level monitoring based on Bluetooth Low Energy technology (BLE, and a web service for monitoring and control of the wandering patients. Due to battery limitations of smart devices with sensors, the mobile application includes energy-efficient handling and transmission policies to make more efficient the transmission of medical information from the sensor-based smart device to the web service. In turn, the web service provides e-health control services for patients and caregivers. Through the platform functionality, caregivers (and patients can receive notifications and suggestions in response to emergency, contingency situations, or deviations from health and mobility patterns of the wandering patients. This paper describes a platform that conceals continuous monitoring with energy-efficient applications in favor of e-health control of wandering patients.

  6. Persons with dementia missing in the community: Is it wandering or something unique?

    Directory of Open Access Journals (Sweden)

    Fernandez Rachael M

    2011-06-01

    Full Text Available Abstract Background At some point in the disease process many persons with dementia (PWD will have a missing incident and be unable to safely return to their care setting. In previous research studies, researchers have begun to question whether this phenomenon should continue to be called wandering since the antecedents and characteristics of a missing incident are dissimilar to accepted definitions of wandering in dementia. The purpose of this study was to confirm previous findings regarding the antecedents and characteristics of missing incidents, understand the differences between those found dead and alive, and compare the characteristics of a missing incident to that of wandering. Methods A retrospective design was used to analyse 325 newspaper reports of PWD missing in the community. Results The primary antecedent to a missing incident, particularly in community-dwelling PWD, was becoming lost while conducting a normal and permitted activity alone in the community. The other common antecedent was a lapse in supervision with the expectation that the PWD would remain in a safe location but did not. Deaths most commonly occurred in unpopulated areas due to exposure and drowning. Those who died were found closer to the place last seen and took longer to find, but there were no significant differences in gender or age. The key characteristics of a missing incident were: unpredictable, non-repetitive, temporally appropriate but spatially-disordered, and while using multiple means of movement (walking, car, public transportation. Missing incidents occurred without the discernible pattern present in wandering such as lapping or pacing, repetitive and temporally-disordered. Conclusions This research supports the mounting evidence that the concept of wandering, in its formal sense, and missing incidents are two distinct concepts. It will be important to further develop the concept of missing incidents by identifying the differences and similarities

  7. Torsion of a wandering spleen. A rare cause of acute abdomen

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    Nwashilli N. Jude

    2015-12-01

    Full Text Available Wandering spleen is a rare condition that accounts for less than 0.25% of all indications for splenectomy. It is characterized by ectopic localization of the spleen owing to the lack or weakening of its ligaments. Torsion is the most common complication due to its long pedicle and high mobility, which may result in acute abdomen. We report a case of torsion in a wandering spleen in a 28-year-old male presenting with an acute abdomen that was treated by splenectomy.

  8. Polarization-beam-splitter-less integrated dual-polarization coherent receiver.

    Science.gov (United States)

    Alonso-Ramos, C; Reyes-Iglesias, P J; Ortega-Moñux, A; Pérez-Galacho, D; Halir, R; Molina-Fernández, I

    2014-08-01

    Conventional dual-polarization coherent receivers require polarization beam splitters for either the signal or the local oscillator path. This severely hinders monolithic integration, since integrated polarization splitting devices often exhibit stringent fabrication tolerances. Here we propose a dual-polarization monolithically integrated coherent receiver architecture that completely avoids the use of polarization splitting elements. Polarization management is instead achieved by adequately engineering the birefringence of the interconnecting waveguides. The resultant receiver is highly tolerant to fabrication deviations and thus offers a completely new route for monolithic integration of dual-polarization receivers without any type of active tuning.

  9. Feynman's path integrals and Bohm's particle paths

    International Nuclear Information System (INIS)

    Tumulka, Roderich

    2005-01-01

    Both Bohmian mechanics, a version of quantum mechanics with trajectories, and Feynman's path integral formalism have something to do with particle paths in space and time. The question thus arises how the two ideas relate to each other. In short, the answer is, path integrals provide a re-formulation of Schroedinger's equation, which is half of the defining equations of Bohmian mechanics. I try to give a clear and concise description of the various aspects of the situation. (letters and comments)

  10. Path coupling and aggregate path coupling

    CERN Document Server

    Kovchegov, Yevgeniy

    2018-01-01

    This book describes and characterizes an extension to the classical path coupling method applied to statistical mechanical models, referred to as aggregate path coupling. In conjunction with large deviations estimates, the aggregate path coupling method is used to prove rapid mixing of Glauber dynamics for a large class of statistical mechanical models, including models that exhibit discontinuous phase transitions which have traditionally been more difficult to analyze rigorously. The book shows how the parameter regions for rapid mixing for several classes of statistical mechanical models are derived using the aggregate path coupling method.

  11. Absence without leave or leave without absence: Examining the interrelations among mind wandering, metacognition and cognitive control.

    Science.gov (United States)

    Drescher, Leonhard Hakon; Van den Bussche, Eva; Desender, Kobe

    2018-01-01

    Despite the abundance of recent publications about mind wandering (i.e., off-task thought), its interconnection with metacognition and cognitive control has not yet been examined. In the current study, we hypothesized that these three constructs would show clear interrelations. Metacognitive capacity was predicted to correlate positively with cognitive control ability, which in turn was predicted to be positively related to resistance to mind wandering during sustained attention. Moreover, it was expected that participants with good metacognitive capacity would be better at the subjective recognition of behaviorally present mind wandering. Three tasks were used: The Sustained Attention to Response Task (SART) to measure mind wandering, a perceptual decision task with confidence ratings to measure metacognitive efficiency, and a conflict task to measure cognitive control. Structural Equation Modelling was used to test the interrelations among the three constructs. As expected, metacognitive efficiency was positively related to cognitive control ability. Surprisingly, there was a negative relation between metacognitive efficiency and the degree to which subjective mind wandering reports tracked the behavioral index of mind wandering. No relation was found between cognitive control and behavioral mind wandering. The results of the current work are the first to shed light on the interrelations among these three constructs.

  12. Level crossing statistics for optical beam wander in a turbulent atmosphere with applications to ground-to-space laser communications.

    Science.gov (United States)

    Yura, Harold T; Fields, Renny A

    2011-06-20

    Level crossing statistics is applied to the complex problem of atmospheric turbulence-induced beam wander for laser propagation from ground to space. A comprehensive estimate of the single-axis wander angle temporal autocorrelation function and the corresponding power spectrum is used to develop, for the first time to our knowledge, analytic expressions for the mean angular level crossing rate and the mean duration of such crossings. These results are based on an extension and generalization of a previous seminal analysis of the beam wander variance by Klyatskin and Kon. In the geometrical optics limit, we obtain an expression for the beam wander variance that is valid for both an arbitrarily shaped initial beam profile and transmitting aperture. It is shown that beam wander can disrupt bidirectional ground-to-space laser communication systems whose small apertures do not require adaptive optics to deliver uniform beams at their intended target receivers in space. The magnitude and rate of beam wander is estimated for turbulence profiles enveloping some practical laser communication deployment options and suggesting what level of beam wander effects must be mitigated to demonstrate effective bidirectional laser communication systems.

  13. Absence without leave or leave without absence: Examining the interrelations among mind wandering, metacognition and cognitive control.

    Directory of Open Access Journals (Sweden)

    Leonhard Hakon Drescher

    Full Text Available Despite the abundance of recent publications about mind wandering (i.e., off-task thought, its interconnection with metacognition and cognitive control has not yet been examined. In the current study, we hypothesized that these three constructs would show clear interrelations. Metacognitive capacity was predicted to correlate positively with cognitive control ability, which in turn was predicted to be positively related to resistance to mind wandering during sustained attention. Moreover, it was expected that participants with good metacognitive capacity would be better at the subjective recognition of behaviorally present mind wandering. Three tasks were used: The Sustained Attention to Response Task (SART to measure mind wandering, a perceptual decision task with confidence ratings to measure metacognitive efficiency, and a conflict task to measure cognitive control. Structural Equation Modelling was used to test the interrelations among the three constructs. As expected, metacognitive efficiency was positively related to cognitive control ability. Surprisingly, there was a negative relation between metacognitive efficiency and the degree to which subjective mind wandering reports tracked the behavioral index of mind wandering. No relation was found between cognitive control and behavioral mind wandering. The results of the current work are the first to shed light on the interrelations among these three constructs.

  14. Autopilot, Mind Wandering, and the Out of the Loop Performance Problem

    Directory of Open Access Journals (Sweden)

    Jonas Gouraud

    2017-10-01

    Full Text Available To satisfy the increasing demand for safer critical systems, engineers have integrated higher levels of automation, such as glass cockpits in aircraft, power plants, and driverless cars. These guiding principles relegate the operator to a monitoring role, increasing risks for humans to lack system understanding. The out of the loop performance problem arises when operators suffer from complacency and vigilance decrement; consequently, when automation does not behave as expected, understanding the system or taking back manual control may be difficult. Close to the out of the loop problem, mind wandering points to the propensity of the human mind to think about matters unrelated to the task at hand. This article reviews the literature related to both mind wandering and the out of the loop performance problem as it relates to task automation. We highlight studies showing how these phenomena interact with each other while impacting human performance within highly automated systems. We analyze how this proximity is supported by effects observed in automated environment, such as decoupling, sensory attention, and cognitive comprehension decrease. We also show that this link could be useful for detecting out of the loop situations through mind wandering markers. Finally, we examine the limitations of the current knowledge because many questions remain open to characterize interactions between out of the loop, mind wandering, and automation.

  15. The Role of Mind-Wandering in Measurements of General Aptitude

    Science.gov (United States)

    Mrazek, Michael D.; Smallwood, Jonathan; Franklin, Michael S.; Chin, Jason M.; Baird, Benjamin; Schooler, Jonathan W.

    2012-01-01

    Tests of working memory capacity (WMC) and fluid intelligence (gF) are thought to capture variability in a crucial cognitive capacity that is broadly predictive of success, yet pinpointing the exact nature of this capacity is an area of ongoing controversy. We propose that mind-wandering is associated with performance on tests of WMC and gF,…

  16. Schooled in Our Own Minds: Mind-Wandering and Mindfulness in the Makings of the Curriculum

    Science.gov (United States)

    Ergas, Oren

    2018-01-01

    Curriculum discourse focuses understandably, on the formal and enacted curriculum; however, studies demonstrate that much of individuals' waking hours are spent in task-unrelated thinking and mind-wandering. No less, this pervasive phenomenon has been shown to affect us in many ways that can be linked to education. This paper examines this…

  17. Educating the Wandering Mind: Pedagogical Mechanisms of Mindfulness for a Curricular Blind Spot

    Science.gov (United States)

    Ergas, Oren

    2016-01-01

    Educational theory and practice have been focusing on educating students as to "how to think." Yet, contemporary neuroscience and psychological research reveal that many of our waking hours are spent in a state of "mind-wandering" characterized by uncontrolled thoughts that have little to do with our concrete present…

  18. Mind wandering at the fingertips: automatic parsing of subjective states based on response time variability

    Science.gov (United States)

    Bastian, Mikaël; Sackur, Jérôme

    2013-01-01

    Research from the last decade has successfully used two kinds of thought reports in order to assess whether the mind is wandering: random thought-probes and spontaneous reports. However, none of these two methods allows any assessment of the subjective state of the participant between two reports. In this paper, we present a step by step elaboration and testing of a continuous index, based on response time variability within Sustained Attention to Response Tasks (N = 106, for a total of 10 conditions). We first show that increased response time variability predicts mind wandering. We then compute a continuous index of response time variability throughout full experiments and show that the temporal position of a probe relative to the nearest local peak of the continuous index is predictive of mind wandering. This suggests that our index carries information about the subjective state of the subject even when he or she is not probed, and opens the way for on-line tracking of mind wandering. Finally we proceed a step further and infer the internal attentional states on the basis of the variability of response times. To this end we use the Hidden Markov Model framework, which allows us to estimate the durations of on-task and off-task episodes. PMID:24046753

  19. The ARSQ 2.0 reveals age and personality effects on mind-wandering experiences

    NARCIS (Netherlands)

    Diaz, B Alexander; Van Der Sluis, Sophie; Benjamins, Jeroen S; Stoffers, Diederick; Hardstone, Richard; Mansvelder, Huibert D; Van Someren, Eus J W; Linkenkaer-Hansen, Klaus

    2014-01-01

    The human brain frequently generates thoughts and feelings detached from environmental demands. Investigating the rich repertoire of these mind-wandering experiences is challenging, as it depends on introspection and mapping its content requires an unknown number of dimensions. We recently developed

  20. Insight of scent: experimental evidence of olfactory capabilities in the wandering albatross (Diomedea exulans).

    Science.gov (United States)

    Mardon, J; Nesterova, A P; Traugott, J; Saunders, S M; Bonadonna, F

    2010-02-15

    Wandering albatrosses routinely forage over thousands of kilometres of open ocean, but the sensory mechanisms used in the food search itself have not been completely elucidated. Recent telemetry studies show that some spatial behaviours of the species are consistent with the 'multimodal foraging strategy' hypothesis which proposes that birds use a combination of olfactory and visual cues while foraging at sea. The 'multimodal foraging strategy' hypothesis, however, still suffers from a lack of experimental evidence, particularly regarding the olfactory capabilities of wandering albatrosses. As an initial step to test the hypothesis, we carried out behavioural experiments exploring the sensory capabilities of adult wandering albatrosses at a breeding colony. Three two-choice tests were designed to investigate the birds' response to olfactory and visual stimuli, individually or in combination. Perception of the different stimuli was assessed by comparing the amount of exploration directed towards an 'experimental' display or a 'control' display. Our results indicate that birds were able to perceive the three types of stimulus presented: olfactory, visual and combined. Moreover, olfactory and visual cues were found to have additional effects on the exploratory behaviours of males. This simple experimental demonstration of reasonable olfactory capabilities in the wandering albatross supports the 'multimodal foraging strategy' and is consistent with recent hypotheses of the evolutionary history of procellariiforms.

  1. On the relation between reading difficulty and mind-wandering: a section-length account.

    Science.gov (United States)

    Forrin, Noah D; Risko, Evan F; Smilek, Daniel

    2017-11-01

    In many situations, increasing task difficulty decreases thoughts that are unrelated to the task (i.e., mind-wandering). In the context of reading, however, recent research demonstrated that increasing passage reading difficulty actually increases mind-wandering rates (e.g., Feng et al. in Psychon Bull Rev 20:586-592, 2013). The primary goal of this research was to elucidate the mechanism that drives this positive relation. Across Experiments 1-3, we found evidence that the effect of Flesch-Kincaid reading difficulty on mind-wandering is partially driven by hard passages having longer sections of text (i.e., more words per screen) than easy passages when passages are presented one sentence at a time. In Experiment 4, we controlled for reading difficulty, and found that section length was positively associated with mind-wandering rates. We conclude by proposing that individuals may tend to disengage their attention from passages with relatively long sections of text because they appear to be more demanding than passages with shorter sections (even though objective task demands are equivalent).

  2. Exploring the Link between Mind Wandering, Mindfulness, and Creativity: A Multidimensional Approach

    Science.gov (United States)

    Agnoli, Sergio; Vanucci, Manila; Pelagatti, Claudia; Corazza, Giovanni Emanuele

    2018-01-01

    Even if mind wandering (MW) and mindfulness have traditionally been intended as separate and antithetical constructs, the roles of these 2 mental states on creative behavior were jointly explored in this article. In particular, MW was analyzed in light of a recent approach suggesting a differentiation between deliberate and spontaneous MW, whereas…

  3. Dispatching the wandering mind? Toward a laboratory method for cuing "spontaneous" off-task thought

    Directory of Open Access Journals (Sweden)

    Jennifer C. McVay

    2013-09-01

    Full Text Available Cognitive psychologists and neuroscientists study most phenomena of attention by measuring subjects’ overt responses to discrete environmental stimuli that can be manipulated to test competing theories. The mind-wandering experience, however, cannot be locally instigated by cleverly engineered stimuli. Investigators must therefore rely on correlational and observational methods to understand subjects’ flow of thought, which is only occasionally and indirectly monitored. In an effort toward changing this state of affairs, we present four experiments that develop a method for inducing mind-wandering episodes – on demand – in response to task-embedded cues. In an initial laboratory session, subjects described their personal goals and concerns across several life domains (amid some filler questionnaires. In a second session, 48 hours later, subjects completed a go/no-go task in which they responded to the perceptual features of words; unbeknownst to subjects, some stimulus words were presented in triplets to represent the personal concerns they had described in session 1. Thought probes appearing shortly after these personal-goal triplets indicated that, compared to control triplets, priming subjects’ concerns increased mind-wandering rate by about 3 – 4%. We argue that this small effect is, nonetheless, a promising development toward the pursuit of an experimentally informed, theory-driven science of mind wandering.

  4. Involvement in Activities and Wandering in Nursing Home Residents With Cognitive Impairment

    NARCIS (Netherlands)

    Volicer, L.; van der Steen, J.T.; Frijters, D.H.M.

    2013-01-01

    Objectives: Analysis of a relationship between wandering and involvement in meaningful activities in nursing home residents with cognitive impairment. DESIGN:: Cross-sectional analysis of the Minimum Data Set information. SETTING:: The analyses were conducted on 8 nursing homes in the Netherlands.

  5. Analysis of Unbound Aggregate Layer Deformation Behavior from Full Scale Aircraft Gear Loading with Wander

    Science.gov (United States)

    Donovan, Phillip Raymond

    2009-01-01

    This study focuses on the analysis of the behavior of unbound aggregates to offset wheel loads. Test data from full-scale aircraft gear loading conducted at the National Airport Pavement Test Facility (NAPTF) by the Federal Aviation Administration (FAA) are used to investigate the effects of wander (offset loads) on the deformation behavior of…

  6. Wanderers y Valparaíso: Fútbol, imaginarios y cultura urbana en el puerto principal

    Directory of Open Access Journals (Sweden)

    Sebastián Ponce Olmos

    2015-07-01

    Full Text Available Resumen En el artículo se revisan y vislumbran los imaginarios urbanos de la ciudad de Valparaíso que se hacen manifiestos a raíz del estudio de uno de los símbolos más relevantes de la ciudad: la institución deportiva Santiago Wanderers. A través de una estrategia metodológica basada en la investigación documental, observaciones y entrevistas, se da cuenta de la emergencia de imaginarios urbanos de la ciudad durante la época de existencia del club porteño (1892 a la actualidad. Desde la fundación del club hasta el inicio de la participación de Wanderers en el profesionalismo, se aprecia la invención de un mito fundacional y representaciones que llenan al símbolo. Desde 1942 en adelante, se avizora la construcción de tres imaginarios: el imaginario wanderino de Valparaíso, el imaginario de la resistencia porteña y el imaginario patrimonial de Santiago Wanderers. En el presente texto se pone énfasis en el imaginario wanderino de Valparaíso y el imaginario patrimonial de Valparaíso. Abstract In the article are reviewed the urban imaginary of the city of Valparaiso which become manifest from the study of one of the most important symbols of the city: Santiago Wanderers sports institution. Through a methodological strategy based on desk research, observations and interviews, we realize the emergence of urban imagery of the city during the time of existence of the sport team (1892-present. Since the founding of the club until the beginning of the participation of Wanderers in the professionalism, the invention of a founding myth and representations that fill the symbol shown. From 1942 onwards, the construction of three imaginary is looming: imaginary wanderino of Valparaíso, imaginary of resistance of Valparaíso and heritage Imaginary of Santiago Wanderers. Here, the emphasis is placed on the imaginary wanderino of Valparaiso and heritage Imaginary of Santiago Wanderers.

  7. Probe-caught spontaneous and deliberate mind wandering in relation to self-reported inattentive, hyperactive and impulsive traits in adults.

    Science.gov (United States)

    Arabacı, Gizem; Parris, Benjamin A

    2018-03-07

    Research has revealed a positive relationship between types of mind wandering and ADHD at clinical and subclinical levels. However, this work did not consider the relationship between mind wandering and the core symptoms of ADHD: inattention, hyperactivity and impulsivity. Given that the DMS-V attributes mind wandering to inattention only, and that only inattention is thought to result from impairment to the executive function linked to mind wandering, the present research sought to examine this relationship in 80 undiagnosed adults. Using both standard and easy versions of the Sustained Attention to Response Task (SART) we measured both spontaneous and deliberate mind wandering. We found that spontaneous mind wandering was related to self-reported inattentive traits when the task was cognitively more challenging (standard SART). However, hyperactive and impulsive traits were related to spontaneous mind wandering independent of task difficulty. The results suggest inattentive traits are not uniquely related to mind wandering; indeed, adults with hyperactive/impulsive traits were more likely to experience mind wandering, suggesting that mind wandering might not be useful diagnostic criteria for inattention.

  8. Beyond V40.31: Narrative Phenomenology of Wandering in Autism and Dementia.

    Science.gov (United States)

    Solomon, Olga; Lawlor, Mary C

    2018-01-24

    Research on autism spectrum disorder (ASD) and on Alzheimer's Disease (AD) and other types of dementia describes a behaviour called 'wandering', a term that denotes movement through space lacking intention or exact destination, as when a person is disoriented or not self-aware. In the U.S., 'wandering' in both ASD and AD has been examined mostly from a management and prevention perspective. It prioritizes safety while primarily overlooking personal experiences of those who 'wander' and their families, thus limiting the range of potentially effective strategies to address this issue. Communicative challenges faced by many people diagnosed with ASD and AD further obscure the experiential, existential aspects of 'wandering'. This article reflects an increasing concern of social science scholars interested in whether and how the conceptual and practical strategies to address 'wandering' are informed by the situated experiences of people with cognitive and developmental disabilities and their families. We examine 'wandering' at the intersections of personal experience, family life, clinical practice, public health policy, and legislation, as a conceptually rich site where notions of personhood, subjectivity, intentionality, and quality of life powerfully and consequentially converge to impact the lives of many people with ASD and AD, and their families. We draw upon critical autism studies describing how attributions of personhood, subjectivity, intentionality, rational agency, and moral autonomy of people with ASD have been contingent upon the norms and conventions governing movement of the human body through space (Hilton, Afr Am Rev 50(2):221-235, 2017). When this movement is deemed aberrant, the person may be construed as irrational, a danger to self because of a lack of self-awareness, and a danger to others because of a lack of empathy. These attributions put the person at risk of being excluded from the considerations and, more importantly, the obligations of the

  9. Multidetector computed tomography findings of mesenteroaxial gastric volvulus combined with torsion of wandering spleen: A case report and literature review

    Energy Technology Data Exchange (ETDEWEB)

    Youn, In Kyung; Ku, Young Mi; Lee, Su Lim [Dept. of Radiology, Uijeongbu St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu (Korea, Republic of)

    2016-05-15

    Gastric volvulus, defined as an abnormal rotation of stomach, may be idiopathic or secondary to abnormal fixation of intraperitoneal visceral ligaments. Wandering spleen is a movable spleen resulting from absence or underdevelopment of the splenic supporting ligaments that suspend the spleen to its normal position in the left part of the supramesocolic compartment of the abdomen. Wandering spleen increases the risk of splenic torsion. Both gastric volvulus and splenic torsion are potentially life-threatening if not urgently managed with surgery. Prompt and accurate diagnosis based on multidetector computed tomography (MDCT) is crucial to prevent unforeseen complications. Gastric volvulus and coexistent torsion of wandering spleen is a very rare condition. Herein, we described a case of gastric volvulus associated with wandering spleen and intestinal non-rotation in a 15-year-old girl focusing on MDCT findings.

  10. Polarization Techniques for Mitigation of Low Grazing Angle Sea Clutter

    Science.gov (United States)

    2017-01-01

    standard CFAR false alarm rate while maintaining detections on objects of interest. Moreover, PCL is elegant : It exploits fundamental characteristics of both...cannot measure polarization. Polarization is defined by the path traced by the tip of an EM wave’s electric field vector over one period of propagation...vector phasor propagating in the +z direction. Polarization is defined by the path traced by the tip of this electric field vector phasor over one

  11. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  12. Wandering pathways in the regulation of innate immunity and inflammation.

    Science.gov (United States)

    Mantovani, Alberto

    2017-12-01

    Tumor-associated macrophages (TAM) have served as a paradigm of cancer-related inflammation. Moreover, investigations on TAM have led to the dissection of macrophage plasticity and polarization and to the discovery and analysis of molecular pathways of innate immunity, in particular cytokines, chemokines and PTX3 as a prototypic fluid phase pattern recognition molecule. Mechanisms of negative regulation are complex and include decoy receptors, receptor antagonists, anti-inflammatory cytokines and the signalling regulator IL-1R8. In this review, topics and open issues in relation to regulation of innate immunity and inflammation are discussed: 1) how macrophage and neutrophil plasticity and polarization underlie diverse pathological conditions ranging from autoimmunity to cancer and may pave the way to innovative diagnostic and therapeutic approaches; 2) the key role of decoy receptors and negative regulators (e.g. IL-1R2, ACKR2, IL-1R8) in striking a balance between amplification of immunity and resolution versus uncontrolled inflammation and tissue damage; 3) role of humoral innate immunity, illustrated by PTX3, in resistance against selected microbes, regulation of inflammation and immunity and tissue repair, with implications for diagnostic and therapeutic translation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Polarization dynamics of VCSELs in external cavities

    Science.gov (United States)

    Marconi, M.; Javaloyes, J.; Barland, S.; Balle, S.; Giudici, M.

    2014-05-01

    We review the dynamics of VCSELs that experience both Polarization-Selective Feedback (PSF) and Crossed- Polarization Reinjection (XPR). Different regimes of regular pulsation were found. For strong enough XPR levels, the VCSEL emission in each of its linearly-polarized components displays a square-wave modulation which regularity is greatly enhanced by small levels of PSF. Such a square-wave is in antiphase for the two polarizations, and it turns out to be stable and robust over broad intervals of current. The frequency of the square-wave is determined by the length of the XPR arm. For weak levels of PSF and XPR, the VCSEL emits a regular train of short optical pulses arising from the locking of the modes in the PSF cavity. The frequency of the pulse train is stable on short time scales, but it wanders with a characteristic time scale of hundreds of roundtrips in the PSF cavity. The experimental results are successfully explained by an extension of the Spin-Flip Model that incorporates gain saturation and the effects of PSF and XPR.

  14. Quantifying the Statistics of Animal Motion: Lévy Flights of the Wandering Albatross

    Science.gov (United States)

    Viswanathan, Gandhimohan M.

    1998-03-01

    Lévy flights are commonly observed in physical and biological systems(See, e.g., M. F. Shlesinger, G. Zaslavsky and U. Frisch, eds., Lévy flights and Related Topics in Physics) (Springer, Berlin, 1995)., raising the possibility that similar random walks may be used to describe animal motion. Here we discuss recent findings showing that the Wandering Albatross and other animals may perform Lévy flights when foraging( G. M. Viswanathan, V. Afanasyev, S. V. Buldyrev, E. J. Murphy, P. A. Prince and H. E. Stanley, ``Lévy Flight Search Patterns of Wandering Albatrosses,'' Nature) 381, 413--415 (1996). We further examine how such random walks may confer biological advantages and discuss recent findings which suggest that under certain conditions there is a universal power law exponent which characterizes Lévy flight foraging ( G. M. Viswanathan, Sergey V. Buldyrev, Shlomo Havlin, M. G. E. da Luz, E. P. Raposo and H. E. Stanley, preprint.).

  15. Orientation in the wandering albatross: interfering with magnetic perception does not affect orientation performance.

    Science.gov (United States)

    Bonadonna, F; Bajzak, C; Benhamou, S; Igloi, K; Jouventin, P; Lipp, H P; Dell'Omo, G

    2005-03-07

    After making foraging flights of several thousands of kilometers, wandering albatrosses (Diomedea exulans) are able to pinpoint a specific remote island where their nests are located. This impressive navigation ability is highly precise but its nature is mysterious. Here we examined whether albatrosses rely on the perception of the Earth's magnetic field to accomplish this task. We disturbed the perception of the magnetic field using mobile magnets glued to the head of nine albatrosses and compared their performances with those of 11 control birds. We then used satellite telemetry to monitor their behavior. We found that the ability of birds to home specific nest sites was unimpaired by this manipulation. In particular, experimental and control birds did not show significant differences with respect to either foraging trip duration, or length, or with respect to homing straightness index. Our data suggest that wandering albatrosses do not require magnetic cues to navigate back to their nesting birds.

  16. Single-incision laparoscopic splenectomy and splenic autotransplantation for an enlarged wandering spleen with torsion.

    Science.gov (United States)

    Katsura, Shunsaku; Kawamura, Daichi; Harada, Eijiro; Enoki, Tadahiko; Hamano, Kimikazu

    2014-06-01

    A wandering spleen is a rare condition in which the spleen is not located in the left upper quadrant, but instead is found in the lower abdomen or in the pelvic region because of the laxity of the peritoneal attachments. The unusually long pedicle is susceptible to twisting, which can lead to ischemia, and eventually to necrosis. We herein report a case of an enlarged wandering spleen with torsion, successfully treated by single-incision laparoscopic splenectomy and autotransplantation. The transplanted splenic tissues could be identified on a spleen scintigram obtained 3 months after the surgery. Howell-Jolly bodies were not observed in blood specimens. This procedure is able to prevent an overwhelming postsplenectomy infection, and leads to satisfactory cosmetic results.

  17. Wander Lust: Genre, Sexuality and Identity in Ana Kokkinos’s Head On

    Directory of Open Access Journals (Sweden)

    Joe Hardwick

    2011-04-01

    Full Text Available While the road movie has long held a privileged place in Australian cinema, less prevalent, though increasingly present, has been the street movie, which—like its road movie cousin—poses important questions about identity in tracing the trajectory of its wanderer protagonists. The most remarkable recent example of an Australian street movie is Ana Kokkinos’s 1997 feature Head On. The film recounts a day in the life of a late adolescent Greek-Australian male who wanders the streets participating in sexual encounters with mainly, though not exclusively, other men. Whereas reviews and articles have generally read the film as a coming out narrative, this article—with reference to Ross Chambers’ theories on digressive narratives in his book Loiterature—will argue that Head On rejects the simplistic teleology of the coming out story in favour of a much more complex understanding of adolescent male sexuality.

  18. Pindola in Korea and Japan: Is the Wandering Jew Coming from East Asia?

    Directory of Open Access Journals (Sweden)

    Beatrix MECSI

    2014-12-01

    Full Text Available The legend of the Wandering Jew became very popular, especially from the 17th century Western Europe. The story of punishment by eternal life until the next coming of Jesus Christ has parallels with the Buddhist legend of Pindola Bharadvaja, a disciple of Shakyamuni Buddha who was also punished by eternal life until the coming of the Future Buddha, Maitreya. The similarities were dealt with the Japanese polymath, Minakata Kumagusu (1899 and Walter Edwards (1902 in the turn of the 20th century, claiming that the story of the Wandering Jew was influenced by the Asian legends of Pindola. In this paper I show that even if we do not have convincing evidences for proving any historical connections between these legends, the myth of eternal life as a punishment is an interesting idea, which appears in many traditions, forming layers on the existing and ever-growing traditions of myths and pictorial representations.

  19. Attentional disengagements in educational contexts: a diary investigation of everyday mind-wandering and distraction.

    Science.gov (United States)

    Unsworth, Nash; McMillan, Brittany D

    2017-01-01

    The present study examined everyday attentional disengagements in educational contexts. Undergraduate students completed various cognitive ability measures in the laboratory and recorded everyday mind-wandering and distraction in a diary over the course of a week. Participants reported mind-wandering and being distracted both in class and while studying and there were a number of different subtypes of attentional disengagements. Individual differences in cognitive abilities were related to some, but not all, everyday attentional disengagements and motivation and interest in classes were related to specific subtypes of disengagements. Finally, academic performance was related to fluid intelligence and motivation, but not to everyday disengagements. These results provide importance evidence on the different types of attentional disengagements that are prevalent in undergraduate students and for whom disengagements are most likely.

  20. A case of torsion of the wandering spleen presenting as hypersplenism and gastric fundal varices.

    Science.gov (United States)

    Irak, Kader; Esen, Irfan; Keskın, Murat; Emınler, Ahmet Tarık; Ayyildiz, Talat; Kaya, Ekrem; Kiyici, Murat; Gürel, Selim; Nak, Selim Giray; Gülten, Macit; Dolar, Enver

    2011-02-01

    Wandering spleen is the displacement of the spleen from its normal location due to the loss or weakening of ligaments that hold the spleen in the left upper quadrant. The possibility of torsion of the spleen is high due to the long and mobile nature of the vascular pedicle. Generally, cases are asymptomatic. Under conditions of delayed diagnosis, symptoms of splenomegaly, left portal hypertension, gastric fundal varices, and hypersplenism may present as a result of development of vascular congestion associated with chronic torsion. There are only a few cases in the literature reporting the association of wandering spleen and fundal varices. We report herein the case of a 55-year-old female who admitted to our clinic with complaints of fatigue and epigastric pain. She was determined to have gastric fundal varices and hypersplenism secondary to the development of left portal hypertension due to chronic splenic torsion.

  1. A Wandering Mind Does Not Stray Far from Home: The Value of Metacognition in Distant Search

    OpenAIRE

    Kudesia, Ravi S.; Baer, Markus; Elfenbein, Hillary Anger

    2015-01-01

    When faced with a problem, how do individuals search for potential solutions? In this article, we explore the cognitive processes that lead to local search (i.e., identifying options closest to existing solutions) and distant search (i.e., identifying options of a qualitatively different nature than existing solutions). We suggest that mind wandering is likely to lead to local search because it operates by spreading activation from initial ideas to closely associated ideas. This reduces the l...

  2. Is the relationship between mind wandering and attention culture-specific?

    OpenAIRE

    Gonçalves, Óscar F.; Oliveira-Silva, Patrícia; Souza-Queiroz, Julia de; Amaro, Edson; Rêgo, Gabriel; Leite, Jorge; Carvalho, Sandra; Fregni, Felipe; Boggio, Paulo S.

    2017-01-01

    There is increasing evidence that both mind wandering (MW) and attention are influenced by culture. However, studies on the interference between MW and attention across cultures are virtually nonexistent. Here we researched how individuals from 2 cultures (Portuguese, Brazilian) differ in terms of type of thoughts and content of MW during the course of the attention network task (ANT). Additionally, we tested the existence of culture-specific associations between type of thoughts and content ...

  3. Taming a wandering attention: short-form mindfulness training in student cohorts.

    Science.gov (United States)

    Morrison, Alexandra B; Goolsarran, Merissa; Rogers, Scott L; Jha, Amishi P

    2014-01-06

    Mindfulness training (MT) is a form of mental training in which individuals engage in exercises to cultivate an attentive, present centered, and non-reactive mental mode. The present study examines the putative benefits of MT in University students for whom mind wandering can interfere with learning and academic success. We tested the hypothesis that short-form MT (7 h over 7 weeks) contextualized for the challenges and concerns of University students may reduce mind wandering and improve working memory. Performance on the sustained attention to response task (SART) and two working memory tasks (operation span, delayed-recognition with distracters) was indexed in participants assigned to a waitlist control group or the MT course. Results demonstrated MT-related benefits in SART performance. Relative to the control group, MT participants had higher task accuracy and self-reported being more "on-task" after the 7-week training period. MT did not significantly benefit the operation span task or accuracy on the delayed-recognition task. Together these results suggest that while short-form MT did not bolster working memory task performance, it may help curb mind wandering and should, therefore, be further investigated for its use in academic contexts.

  4. Taming a Wandering Attention: Short-Form Mindfulness Training in Student Cohorts

    Directory of Open Access Journals (Sweden)

    Alexandra B. Morrison

    2014-01-01

    Full Text Available Mindfulness training (MT is a form of mental training in which individuals engage in exercises to cultivate an attentive, present centered, and non-reactive mental mode. The present study examines the putative benefits of MT in University students for whom mind wandering can interfere with learning and academic success. We tested the hypothesis that short-form MT (7 hours over 7 weeks contextualized for the challenges and concerns of University students may reduce mind wandering and improve working memory. Performance on the sustained attention response task (SART and two working memory tasks (operation span, delayed-recognition with distracters was indexed in participants assigned to a waitlist control group or the MT course. Results demonstrated MT-related benefits in SART performance. Relative to the control group, MT participants had higher task accuracy and self-reported being more on-task after the 7-week training period. MT did not significantly benefit the operation span task or accuracy on the delayed-recognition task. Together these results suggest that while short-form MT did not bolster working memory task performance, it may help curb mind wandering and should, therefore, be further investigated for its use in academic contexts.

  5. [Acute torsion of wandering spleen: a rare cause of acute abdomen].

    Science.gov (United States)

    de Andrés-Asenjo, Beatriz; Fernández-González, Nuria

    2012-01-01

    Wandering spleen is a rare clinical entity characterized by an anomalous position of the spleen in the abdomen due to impaired splenic ligamentous attachments that produce an elongation of the vascular pedicle. This makes a partial or complete volvulus of the vascular axis more likely. Wandering spleen's clinical presentation is variable--from an asymptomatic patient to one with chronic abdominal pain or an acute abdomen. The most common complication is the acute torsion of the splenic pedicle causing acute abdominal pain. A 30-year-old woman who turned up at the Emergency Department with acute abdominal pain. Diagnostic imaging (ultrasonography and computerized axial tomography) revealed a huge spleen in an abnormal location and without vascularization. An urgent splenectomy was performed. Acute torsion of wandering spleen is a rare cause of acute abdomen, which makes early diagnosis difficult and can result in delayed treatment. This would lead to having to perform a splenectomy. Due to splenic necrosis or infarction, which increases the risk of postsplenectomy sepsis.

  6. Global population structure and taxonomy of the wandering albatross species complex.

    Science.gov (United States)

    Burg, T M; Croxall, J P

    2004-08-01

    A recent taxonomic revision of wandering albatross elevated each of the four subspecies to species. We used mitochondrial DNA and nine microsatellite markers to study the phylogenetic relationships of three species (Diomedea antipodensis, D. exulans and D. gibsoni) in the wandering albatross complex. A small number of samples from a fourth species, D. dabbenena, were analysed using mitochondrial DNA only. Mitochondrial DNA sequence analyses indicated the presence of three distinct groups within the wandering albatross complex: D. exulans, D. dabbenena and D. antipodensis/D. gibsoni. Although no fixed differences were found between D. antipodensis and D. gibsoni, a significant difference in the frequency of a single restriction site was detected using random fragment length polymorphism. Microsatellite analyses using nine variable loci, showed that D. exulans, D. antipodensis and D. gibsoni were genetically differentiated. Despite the widespread distribution of D. exulans, we did not detect any genetic differentiation among populations breeding on different island groups. The lower level of genetic differentiation between D. antipodensis and D. gibsoni should be reclassified as D. antipodensis. Within the context of the current taxonomy, these combined data support three species: D. dabbenena, D. exulans and D. antipodensis. Copyright 2004 Blackwell Publishing Ltd

  7. Being a Grump Only Makes Things Worse: A Transactional Account of Acute Stress on Mind Wandering

    Directory of Open Access Journals (Sweden)

    Melaina T Vinski

    2013-11-01

    Full Text Available The current work investigates the influence of acute stress on mind wandering. Participants completed the Positive and Negative Affect Scale as a measure of baseline negative mood, and were randomly assigned to either the high stress or low stress version of the Trier Social Stress Test. Participants then completed the Sustained Attention to Response Task (SART as a measure of mind wandering behaviour. In Experiment 1, participants reporting a high degree of negative mood that were exposed to the high stress condition were more likely to engage in a variable response time, make more errors, and were more likely to report thinking about the stressor relative to participants that report a low level of negative mood. These effects diminished throughout task performance, suggesting that acute stress induces a temporary mind wandering state in participants with a negative mood. The temporary affect-dependent deficits observed in Experiment 1 were replicated in Experiment 2, with the high negative mood participants demonstrating limited resource availability (indicated by pupil diameter immediately following stress induction. These experiments provide novel evidence to suggest that acute psychosocial stress briefly suppresses the availability of cognitive resources and promotes an internally-oriented focus of attention in participants with a negative mood.

  8. Everyday Attention and Lecture Retention: The Effects of Time, Fidgeting, and Mind Wandering

    Directory of Open Access Journals (Sweden)

    James eFarley

    2013-09-01

    Full Text Available We have all had our thoughts wander from the immediate task at hand. The emerging embodied cognition literature emphasizes the role that the body plays in human thought, and raises the possibility that changes in attentional focus may be associated with changes in body behaviour. Recent research has found that when individuals view a lecture, mind wandering increases as a function of time. In the present study we asked whether this decline in attention during lecture viewing was associated with fidgeting. Participants were filmed while they watched a 40-minute lecture video, and at regular 5 minute intervals provided ratings of their attentiveness. Following the lecture, participant's memory for the material was assessed. Fidgeting behaviour was coded from video recordings of each session. Results indicated that attention to, and retention of, lecture material declined as a function of time on task. Critically, and as predicted, fidgeting also increased with time on task. We also found that the relation between fidgeting and retention was significant even when the role of attention was factored into the equation, suggesting that fidgeting makes a unique contribution to retention of lecture material over and above that contributed by an individual’s attention. We propose a novel non-attentional stress-based account of fidgeting and how this impacts retention for lecture material over and above changes in levels in mind wandering vis-a-vis changes in attention.

  9. Polarization, political

    NARCIS (Netherlands)

    Wojcieszak, M.; Mazzoleni, G.; Barnhurst, K.G.; Ikeda, K.; Maia, R.C.M.; Wessler, H.

    2015-01-01

    Polarization has been studied in three different forms: on a social, group, and individual level. This entry first focuses on the undisputed phenomenon of elite polarization (i.e., increasing adherence of policy positions among the elites) and also outlines different approaches to assessing mass

  10. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  11. Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting polar bears of the Beaufort Sea region are exposed to mineral and petroleum extraction and related human activities such as shipping road-building, and seismic testing (Stirling 1990).Little was known at the start of this project about how polar bears move about in their environment, and although it was understood that many bears travel across political borders, the boundaries of populations had not been delineated (Amstrup 1986, Amstrup et al. 1986, Amstrup and DeMaster 1988, Garner et al. 1994, Amstrup 1995, Amstrup et al. 1995, Amstrup 2000).As human populations increase and demands for polar bears and other arctic resources escalate, managers must know the sizes and distributions of the polar bear populations. Resource managers also need reliable estimates of breeding rates, reproductive intervals, litter sizes, and survival of young and adults.Our objectives for this research were 1) to determine the seasonal and annual movements of polar bears in the Beaufort Sea, 2) to define the boundaries of the population(s) using this region, 3) to determine the size and status of the Beaufort Sea polar bear population, and 4) to establish reproduction and survival rates (Amstrup 2000).

  12. Multi-Dimensional Path Queries

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    1998-01-01

    that connects a pair of paths. A path expression is a function that maps a set of path sets into a path set. Path sets can be joined, filtering conditions can restrict the set of qualifying paths, and aggregation functions can be applied to path elements. In particular, the aggregation function SET can be used...... to create nested path structures. We present an SQL-like query language that is based on path expressions and we show how to use it to express multi-dimensional path queries that are suited for advanced data analysis in decision support environments like data warehousing environments...

  13. Hamiltonian path integrals

    International Nuclear Information System (INIS)

    Prokhorov, L.V.

    1982-01-01

    The properties of path integrals associated with the allowance for nonstandard terms reflecting the operator nature of the canonical variables are considered. Rules for treating such terms (''equivalence rules'') are formulated. Problems with a boundary, the behavior of path integrals under canonical transformations, and the problem of quantization of dynamical systems with constraints are considered in the framework of the method

  14. Zero-Slack, Noncritical Paths

    Science.gov (United States)

    Simons, Jacob V., Jr.

    2017-01-01

    The critical path method/program evaluation and review technique method of project scheduling is based on the importance of managing a project's critical path(s). Although a critical path is the longest path through a network, its location in large projects is facilitated by the computation of activity slack. However, logical fallacies in…

  15. Two dimensional simplicial paths

    International Nuclear Information System (INIS)

    Piso, M.I.

    1994-07-01

    Paths on the R 3 real Euclidean manifold are defined as 2-dimensional simplicial strips which are orbits of the action of a discrete one-parameter group. It is proven that there exists at least one embedding of R 3 in the free Z-module generated by S 2 (x 0 ). The speed is defined as the simplicial derivative of the path. If mass is attached to the simplex, the free Lagrangian is proportional to the width of the path. In the continuum limit, the relativistic form of the Lagrangian is recovered. (author). 7 refs

  16. Path integration quantization

    International Nuclear Information System (INIS)

    DeWitt-Morette, C.

    1983-01-01

    Much is expected of path integration as a quantization procedure. Much more is possible if one recognizes that path integration is at the crossroad of stochastic and differential calculus and uses the full power of both stochastic and differential calculus in setting up and computing path integrals. In contrast to differential calculus, stochastic calculus has only comparatively recently become an instrument of thought. It has nevertheless already been used in a variety of challenging problems, for instance in the quantization problem. The author presents some applications of the stochastic scheme. (Auth.)

  17. Distracted by the Unthought - Suppression and Reappraisal of Mind Wandering under Stereotype Threat.

    Directory of Open Access Journals (Sweden)

    Carolin Schuster

    Full Text Available Previous research has found that subtle reminders of negative stereotypes about one's group can lead individuals to underperform on stereotype-relevant tests (e.g., women in math, ethnic minorities on intelligence tests. This so called stereotype threat effect can contribute to systematic group differences in performance that can obscure the true abilities of certain social groups and thereby sustain social inequalities. In the present study, we examined processes underlying stereotype threat effects on women's math performance, specifically focusing on the role of suppression of mind wandering (i.e., task-irrelevant thinking in stereotype threat (ST and no threat (NT situations. Based on a process model of stereotype threat effects on performance, we hypothesized that women under stereotype threat spontaneously suppress mind wandering, and that this suppression impairs performance. An alternative regulation strategy that prevents suppression (i.e., reappraising task-irrelevant thoughts as normal was predicted to prevent stereotype threat effects on performance. We manipulated stereotype threat (ST vs. NT and cognitive regulation strategy (suppression, reappraisal, or no strategy and measured women's performance on a math and a concentration task (N = 113. We expected three groups to perform relatively more poorly: Those in ST with either no strategy or suppression and those in NT with a suppression strategy. We tested the performance of these groups against the remaining three groups hypothesized to perform relatively better: those in NT with no strategy or reappraisal and those in ST with reappraisal. The results showed the expected pattern for participants' math performance, but not for concentration achievement. This pattern suggests that ineffective self-regulation by suppressing mind wandering can at least partly explain stereotype threat effects on performance, whereas a reappraisal strategy can prevent this impairment. We discuss

  18. Distracted by the Unthought – Suppression and Reappraisal of Mind Wandering under Stereotype Threat

    Science.gov (United States)

    Schuster, Carolin; Martiny, Sarah E.; Schmader, Toni

    2015-01-01

    Previous research has found that subtle reminders of negative stereotypes about one’s group can lead individuals to underperform on stereotype-relevant tests (e.g., women in math, ethnic minorities on intelligence tests). This so called stereotype threat effect can contribute to systematic group differences in performance that can obscure the true abilities of certain social groups and thereby sustain social inequalities. In the present study, we examined processes underlying stereotype threat effects on women’s math performance, specifically focusing on the role of suppression of mind wandering (i.e., task-irrelevant thinking) in stereotype threat (ST) and no threat (NT) situations. Based on a process model of stereotype threat effects on performance, we hypothesized that women under stereotype threat spontaneously suppress mind wandering, and that this suppression impairs performance. An alternative regulation strategy that prevents suppression (i.e., reappraising task-irrelevant thoughts as normal) was predicted to prevent stereotype threat effects on performance. We manipulated stereotype threat (ST vs. NT) and cognitive regulation strategy (suppression, reappraisal, or no strategy) and measured women’s performance on a math and a concentration task (N = 113). We expected three groups to perform relatively more poorly: Those in ST with either no strategy or suppression and those in NT with a suppression strategy. We tested the performance of these groups against the remaining three groups hypothesized to perform relatively better: those in NT with no strategy or reappraisal and those in ST with reappraisal. The results showed the expected pattern for participants’ math performance, but not for concentration achievement. This pattern suggests that ineffective self-regulation by suppressing mind wandering can at least partly explain stereotype threat effects on performance, whereas a reappraisal strategy can prevent this impairment. We discuss

  19. Distracted by the Unthought - Suppression and Reappraisal of Mind Wandering under Stereotype Threat.

    Science.gov (United States)

    Schuster, Carolin; Martiny, Sarah E; Schmader, Toni

    2015-01-01

    Previous research has found that subtle reminders of negative stereotypes about one's group can lead individuals to underperform on stereotype-relevant tests (e.g., women in math, ethnic minorities on intelligence tests). This so called stereotype threat effect can contribute to systematic group differences in performance that can obscure the true abilities of certain social groups and thereby sustain social inequalities. In the present study, we examined processes underlying stereotype threat effects on women's math performance, specifically focusing on the role of suppression of mind wandering (i.e., task-irrelevant thinking) in stereotype threat (ST) and no threat (NT) situations. Based on a process model of stereotype threat effects on performance, we hypothesized that women under stereotype threat spontaneously suppress mind wandering, and that this suppression impairs performance. An alternative regulation strategy that prevents suppression (i.e., reappraising task-irrelevant thoughts as normal) was predicted to prevent stereotype threat effects on performance. We manipulated stereotype threat (ST vs. NT) and cognitive regulation strategy (suppression, reappraisal, or no strategy) and measured women's performance on a math and a concentration task (N = 113). We expected three groups to perform relatively more poorly: Those in ST with either no strategy or suppression and those in NT with a suppression strategy. We tested the performance of these groups against the remaining three groups hypothesized to perform relatively better: those in NT with no strategy or reappraisal and those in ST with reappraisal. The results showed the expected pattern for participants' math performance, but not for concentration achievement. This pattern suggests that ineffective self-regulation by suppressing mind wandering can at least partly explain stereotype threat effects on performance, whereas a reappraisal strategy can prevent this impairment. We discuss implications for

  20. Random wandering of laser beams with orbital angular momentum during propagation through atmospheric turbulence.

    Science.gov (United States)

    Aksenov, Valerii P; Kolosov, Valeriy V; Pogutsa, Cheslav E

    2014-06-10

    The propagation of laser beams having orbital angular momenta (OAM) in the turbulent atmosphere is studied numerically. The variance of random wandering of these beams is investigated with the use of the Monte Carlo technique. It is found that, among various types of vortex laser beams, such as the Laguerre-Gaussian (LG) beam, modified Bessel-Gaussian beam, and hypergeometric Gaussian beam, having identical initial effective radii and OAM, the LG beam occupying the largest effective volume in space is the most stable one.

  1. Path planning in changeable environments

    NARCIS (Netherlands)

    Nieuwenhuisen, D.

    2007-01-01

    This thesis addresses path planning in changeable environments. In contrast to traditional path planning that deals with static environments, in changeable environments objects are allowed to change their configurations over time. In many cases, path planning algorithms must facilitate quick

  2. Does prey capture induce area-restricted search? A fine-scale study using GPS in a marine predator, the wandering albatross.

    Science.gov (United States)

    Weimerskirch, Henri; Pinaud, David; Pawlowski, Frédéric; Bost, Charles-André

    2007-11-01

    In a patchy environment, predators are expected to increase turning rate and start an area-restricted search (ARS) when prey have been encountered, but few empirical data exist for large predators. By using GPS loggers with devices measuring prey capture, we studied how a marine predator adjusts foraging movements at various scales in relation to prey capture. Wandering albatrosses use two tactics, sit and wait and foraging in flight, the former tactic being three times less efficient than the latter. During flight foraging, birds caught large isolated prey and used ARS at scales varying from 5 to 90 km, with large-scale ARS being used only by young animals. Birds did not show strong responses to prey capture at a large scale, few ARS events occurred after prey capture, and birds did not have high rates of prey capture in ARS. Only at small scales did birds increase sinuosity after prey captures for a limited time period, and this occurred only after they had caught a large prey item within an ARS zone. When this species searches over a large scale, the most effective search rule was to follow a nearly straight path. ARS may be used to restrict search to a particular environment where prey capture is more predictable and profitable.

  3. Political polarization

    OpenAIRE

    Dixit, Avinash K.; Weibull, Jörgen W.

    2007-01-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  4. Political polarization.

    Science.gov (United States)

    Dixit, Avinash K; Weibull, Jörgen W

    2007-05-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  5. The wandering mind in borderline personality disorder: Instability in self- and other-related thoughts.

    Science.gov (United States)

    Kanske, Philipp; Schulze, Lars; Dziobek, Isabel; Scheibner, Hannah; Roepke, Stefan; Singer, Tania

    2016-08-30

    Diagnostic criteria for borderline personality disorder (BPD) include instability in identity and interpersonal relationships. Here, we probed whether instability is already present in BPD patients' thoughts about themselves and others. We tested BPD patients (N=27) and healthy controls (N=25) with a mind-wandering task that assesses content and variability of stimulus-independent self-generated thoughts. Multi-level modeling revealed that while BPD patients and healthy controls mind-wander to a similar extent, BPD patients' thoughts are colored predominantly negatively. Most importantly, although their thoughts concerned the self and others as much as in controls, they fluctuated more strongly in the degree to which their thoughts concerned themselves and others and also gave more extreme ratings. Self- and other related thoughts that were more extreme were also more negative in valence. The increased variability supports current conceptualizations of BPD and may account for the instability in identity and interpersonal relationships. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. More mind wandering, fewer original ideas: be not distracted during creative idea generation.

    Science.gov (United States)

    Hao, Ning; Wu, Mengxia; Runco, Mark A; Pina, Jeremy

    2015-10-01

    Several studies suggest that mind wandering (MW) benefits creativity when the MW occurs in the incubation period of creative problem solving. The aim of present study was to examine the effects of MW that occurs in the course of creative idea generation. Participants received an Alternative Uses Task (AUT) and were asked to generate ideas for 20min. Their MW frequencies as time passed were measured by means of probe-caught MW. Comparisons of the AUT performances of high and low MW groups revealed that greater MW was associated with lower fluency and originality scores on the AUT. Furthermore, the high MW group showed greater MW as time passed, while the low MW group's MW was steady during the course of idea generation. Accordingly, the originality of idea generation decreased with time passing for the high MW group but was steady for the low MW group. The findings suggest that the MW during the course of creative idea generation is negatively related to creativity, perhaps because the control processes involved in idea generation are impaired by the mind wandering. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. First report of MRI findings in a case of an autoamputated wandering calcified ovary

    Directory of Open Access Journals (Sweden)

    Mahajan PS

    2014-03-01

    Full Text Available Parag Suresh Mahajan, Nazeer Ahamad, Sheik Akbar Hussain Department of Radiology, Al-Khor Hospital, Hamad Medical Corporation, Doha, Qatar Abstract: An autoamputated wandering calcified ovary (AWCO is an extremely rare cause of abdominal calcification in the pediatric population. We present the magnetic resonance imaging (MRI features of AWCO in a child. To our knowledge, the MRI features of AWCO have not been previously described in the published literature. Our case report indicates that the MRI findings are characteristic in the diagnosis of an AWCO and can completely obviate the need for invasive procedures in this mostly benign disease. An AWCO should be considered in all cases of mobile calcific opacities on radiographs in female patients. We advise that MRI be conducted in all suspected cases of AWCO for accurate and noninvasive diagnosis, and regular follow-up should be performed with ultrasound. The findings in our case report have the potential to change the course of investigations and management in suspected cases. Keywords: magnetic resonance imaging, ovary, adnexa, autoamputation, wandering calcification

  8. Attentional Lapses in Attention-Deficit/Hyperactivity Disorder: Blank Rather Than Wandering Thoughts.

    Science.gov (United States)

    Van den Driessche, Charlotte; Bastian, Mikaël; Peyre, Hugo; Stordeur, Coline; Acquaviva, Éric; Bahadori, Sara; Delorme, Richard; Sackur, Jérôme

    2017-10-01

    People with attention-deficit/hyperactivity disorder (ADHD) have difficulties sustaining their attention on external tasks. Such attentional lapses have often been characterized as the simple opposite of external sustained attention, but the different types of attentional lapses, and the subjective experiences to which they correspond, remain unspecified. In this study, we showed that unmedicated children (ages 6-12) with ADHD, when probed during a standard go/no-go task, reported more mind blanking (a mental state characterized by the absence of reportable content) than did control participants. This increase in mind blanking happened at the expense of both focused and wandering thoughts. We also found that methylphenidate reverted the level of mind blanking to baseline (i.e., the level of mind blanking reported by control children without ADHD). However, this restoration led to mind wandering more than to focused attention. In a second experiment, we extended these findings to adults who had subclinical ADHD. These results suggest that executive functions impaired in ADHD are required not only to sustain external attention but also to maintain an internal train of thought.

  9. Magnetization in the South Pole-Aitken basin: Implications for the lunar dynamo and true polar wander

    Science.gov (United States)

    2016-10-14

    lunar dynamo may have been variable in direction. Published by Elsevier Inc. 1 o a M s u t o F R P b w 1 r l h c i n...i n i t a n H ttp://dx.doi.org/10.1016/j.icarus.2016.09.038 019-1035/ Published by Elsevier Inc. rium and Serenitatis basins has...Bethell a , c a Department of Earth & Planetary Sciences , University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA b Red Sky

  10. Paths correlation matrix.

    Science.gov (United States)

    Qian, Weixian; Zhou, Xiaojun; Lu, Yingcheng; Xu, Jiang

    2015-09-15

    Both the Jones and Mueller matrices encounter difficulties when physically modeling mixed materials or rough surfaces due to the complexity of light-matter interactions. To address these issues, we derived a matrix called the paths correlation matrix (PCM), which is a probabilistic mixture of Jones matrices of every light propagation path. Because PCM is related to actual light propagation paths, it is well suited for physical modeling. Experiments were performed, and the reflection PCM of a mixture of polypropylene and graphite was measured. The PCM of the mixed sample was accurately decomposed into pure polypropylene's single reflection, pure graphite's single reflection, and depolarization caused by multiple reflections, which is consistent with the theoretical derivation. Reflection parameters of rough surface can be calculated from PCM decomposition, and the results fit well with the theoretical calculations provided by the Fresnel equations. These theoretical and experimental analyses verify that PCM is an efficient way to physically model light-matter interactions.

  11. Leavitt path algebras

    CERN Document Server

    Abrams, Gene; Siles Molina, Mercedes

    2017-01-01

    This book offers a comprehensive introduction by three of the leading experts in the field, collecting fundamental results and open problems in a single volume. Since Leavitt path algebras were first defined in 2005, interest in these algebras has grown substantially, with ring theorists as well as researchers working in graph C*-algebras, group theory and symbolic dynamics attracted to the topic. Providing a historical perspective on the subject, the authors review existing arguments, establish new results, and outline the major themes and ring-theoretic concepts, such as the ideal structure, Z-grading and the close link between Leavitt path algebras and graph C*-algebras. The book also presents key lines of current research, including the Algebraic Kirchberg Phillips Question, various additional classification questions, and connections to noncommutative algebraic geometry. Leavitt Path Algebras will appeal to graduate students and researchers working in the field and related areas, such as C*-algebras and...

  12. The Delicate Balance between Parental Protection, Unsupervised Wandering, and Adolescents' Autonomy and Its Relation with Antisocial Behavior: The TRAILS Study

    Science.gov (United States)

    Sentse, Miranda; Dijkstra, Jan Kornelis; Lindenberg, Siegwart; Ormel, Johan; Veenstra, Rene

    2010-01-01

    In a large sample of early adolescents (T2: N = 1023; M age = 13.51; 55.5% girls), the impact of parental protection and unsupervised wandering on adolescents' antisocial behavior 2.5 years later was tested in this TRAILS study; gender and parental knowledge were controlled for. In addition, the level of biological maturation and having antisocial…

  13. Why Does Working Memory Capacity Predict Variation in Reading Comprehension? On the Influence of Mind Wandering and Executive Attention

    Science.gov (United States)

    McVay, Jennifer C.; Kane, Michael J.

    2012-01-01

    Some people are better readers than others, and this variation in comprehension ability is predicted by measures of working memory capacity (WMC). The primary goal of this study was to investigate the mediating role of mind wandering experiences in the association between WMC and normal individual differences in reading comprehension, as predicted by the executive-attention theory of WMC (e.g., Engle & Kane, 2004). We used a latent-variable, structural-equation-model approach, testing skilled adult readers on three WMC span tasks, seven varied reading comprehension tasks, and three attention-control tasks. Mind wandering was assessed using experimenter-scheduled thought probes during four different tasks (two reading, two attention-control tasks). The results support the executive-attention theory of WMC. Mind wandering across the four tasks loaded onto a single latent factor, reflecting a stable individual difference. Most importantly, mind wandering was a significant mediator in the relationship between WMC and reading comprehension, suggesting that the WMC-comprehension correlation is driven, in part, by attention control over intruding thoughts. We discuss implications for theories of WMC, attention control, and reading comprehension. PMID:21875246

  14. Temporal focus, temporal distance, and mind-wandering valence: Results from an experience sampling and an experimental study

    NARCIS (Netherlands)

    Spronken, M.; Holland, R.W.; Figner, B.; Dijksterhuis, A.J.

    2016-01-01

    When mind-wandering, people may think about events that happened in the past, or events that may happen in the future. Using experience sampling, we first aimed to replicate the finding that future-oriented thoughts show a greater positivity bias than past-oriented thoughts. Furthermore, we

  15. The delicate balance between parental protection, unsupervised wandering, and adolescents' autonomy and its relation with antisocial behavior : The TRAILS study

    NARCIS (Netherlands)

    Sentse, M.; Dijkstra, J.K.; Lindenberg, S.; Ormel, J.; Veenstra, R.

    In a large sample of early adolescents (T2: N = 1023; M age = 13.51; 55.5% girls), the impact of parental protection and unsupervised wandering on adolescents' antisocial behavior 2.5 years later was tested in this TRAILS study; gender and parental knowledge were controlled for. In addition, the

  16. Do drives drive the train of thought?-Effects of hunger and sexual arousal on mind-wandering behavior.

    Science.gov (United States)

    Rummel, Jan; Nied, Laura

    2017-10-01

    Physiological needs that are currently unfulfilled are known to affect human cognition and behavior. The present study investigates whether and how the temporary activation of two primary physiological needs, namely hunger and sexual arousal, influence both the frequency and the contents of mind-wandering episodes. To induce hunger, one group of participants fasted for a minimum of five hours whereas another group of participants was exposed to audio material with explicit sexual content to provoke sexual arousal. Both groups as well as an additional control group, which had not received hunger instructions and had not been exposed to arousing material of any kind beforehand, performed a reading task during which mind wandering was assessed using a standard experience-sampling method. Results showed that acute hunger but not elevated sexual arousal renders the occurrence of mind-wandering episodes more likely. Induction of both hunger and sexual arousal rendered the occurrence of need-related off-task thoughts more likely and changed time orientations of mind wandering. The present findings are well in line with the assumption that unfulfilled needs regularly achieve cognitive priority and extend the cognitive-priority idea to self-generated thoughts. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Conducting the Train of Thought: Working Memory Capacity, Goal Neglect, and Mind Wandering in an Executive-Control Task

    Science.gov (United States)

    McVay, Jennifer C.; Kane, Michael J.

    2009-01-01

    On the basis of the executive-attention theory of working memory capacity (WMC; e.g., M. J. Kane, A. R. A. Conway, D. Z. Hambrick, & R. W. Engle, 2007), the authors tested the relations among WMC, mind wandering, and goal neglect in a sustained attention to response task (SART; a go/no-go task). In 3 SART versions, making conceptual versus…

  18. Dispatching the wandering mind? Toward a laboratory method for cuing “spontaneous” off-task thought

    Science.gov (United States)

    McVay, Jennifer C.; Kane, Michael J.

    2013-01-01

    Cognitive psychologists and neuroscientists study most phenomena of attention by measuring subjects' overt responses to discrete environmental stimuli that can be manipulated to test competing theories. The mind wandering experience, however, cannot be locally instigated by cleverly engineered stimuli. Investigators must therefore rely on correlational and observational methods to understand subjects' flow of thought, which is only occasionally and indirectly monitored. In an effort toward changing this state of affairs, we present four experiments that develop a method for inducing mind wandering episodes—on demand—in response to task-embedded cues. In an initial laboratory session, subjects described their personal goals and concerns across several life domains (amid some filler questionnaires). In a second session, 48 h later, subjects completed a go/no-go task in which they responded to the perceptual features of words; unbeknownst to subjects, some stimulus words were presented in triplets to represent the personal concerns they had described in session 1. Thought probes appearing shortly after these personal-goal triplets indicated that, compared to control triplets, priming subjects' concerns increased mind wandering rate by about 3–4%. We argue that this small effect is, nonetheless, a promising development toward the pursuit of an experimentally informed, theory-driven science of mind wandering. PMID:24027542

  19. Why Does Working Memory Capacity Predict Variation in Reading Comprehension? On the Influence of Mind Wandering and Executive Attention

    Science.gov (United States)

    McVay, Jennifer C.; Kane, Michael J.

    2012-01-01

    Some people are better readers than others, and this variation in comprehension ability is predicted by measures of working memory capacity (WMC). The primary goal of this study was to investigate the mediating role of mind-wandering experiences in the association between WMC and normal individual differences in reading comprehension, as predicted…

  20. The Wanderer, the Chameleon, and the Warrior: Experiences of Doctoral Students of Color Developing a Research Identity in Educational Administration

    Science.gov (United States)

    Murakami-Ramalho, Elizabeth; Piert, Joyce; Militello, Matthew

    2008-01-01

    In this article, the authors use their personal narratives and collaborative portraits as methods to shed light on the complexities of developing a research identity while journeying through a doctoral program. Using the metaphors of a wanderer, a chameleon, and a warrior, their narratives represent portraits of experiences faced by doctoral…

  1. Vultures of the seas: hyperacidic stomachs in wandering albatrosses as an adaptation to dispersed food resources, including fishery wastes.

    Directory of Open Access Journals (Sweden)

    David Grémillet

    Full Text Available Animals are primarily limited by their capacity to acquire food, yet digestive performance also conditions energy acquisition, and ultimately fitness. Optimal foraging theory predicts that organisms feeding on patchy resources should maximize their food loads within each patch, and should digest these loads quickly to minimize travelling costs between food patches. We tested the prediction of high digestive performance in wandering albatrosses, which can ingest prey of up to 3 kg, and feed on highly dispersed food resources across the southern ocean. GPS-tracking of 40 wandering albatrosses from the Crozet archipelago during the incubation phase confirmed foraging movements of between 475-4705 km, which give birds access to a variety of prey, including fishery wastes. Moreover, using miniaturized, autonomous data recorders placed in the stomach of three birds, we performed the first-ever measurements of gastric pH and temperature in procellariformes. These revealed surprisingly low pH levels (average 1.50±0.13, markedly lower than in other seabirds, and comparable to those of vultures feeding on carrion. Such low stomach pH gives wandering albatrosses a strategic advantage since it allows them a rapid chemical breakdown of ingested food and therefore a rapid digestion. This is useful for feeding on patchy, natural prey, but also on fishery wastes, which might be an important additional food resource for wandering albatrosses.

  2. Why does working memory capacity predict variation in reading comprehension? On the influence of mind wandering and executive attention.

    Science.gov (United States)

    McVay, Jennifer C; Kane, Michael J

    2012-05-01

    Some people are better readers than others, and this variation in comprehension ability is predicted by measures of working memory capacity (WMC). The primary goal of this study was to investigate the mediating role of mind-wandering experiences in the association between WMC and normal individual differences in reading comprehension, as predicted by the executive-attention theory of WMC (e.g., Engle & Kane, 2004). We used a latent-variable, structural-equation-model approach, testing skilled adult readers on 3 WMC span tasks, 7 varied reading-comprehension tasks, and 3 attention-control tasks. Mind wandering was assessed using experimenter-scheduled thought probes during 4 different tasks (2 reading, 2 attention-control). The results support the executive-attention theory of WMC. Mind wandering across the 4 tasks loaded onto a single latent factor, reflecting a stable individual difference. Most important, mind wandering was a significant mediator in the relationship between WMC and reading comprehension, suggesting that the WMC-comprehension correlation is driven, in part, by attention control over intruding thoughts. We discuss implications for theories of WMC, attention control, and reading comprehension.

  3. Lexicographic Path Induction

    DEFF Research Database (Denmark)

    Schürmann, Carsten; Sarnat, Jeffrey

    2009-01-01

    an induction principle that combines the comfort of structural induction with the expressive strength of transfinite induction. Using lexicographic path induction, we give a consistency proof of Martin-Löf’s intuitionistic theory of inductive definitions. The consistency of Heyting arithmetic follows directly...

  4. MEASURING PATH DEPENDENCY

    Directory of Open Access Journals (Sweden)

    Peter Juhasz

    2017-03-01

    Full Text Available While risk management gained popularity during the last decades even some of the basic risk types are still far out of focus. One of these is path dependency that refers to the uncertainty of how we reach a certain level of total performance over time. While decision makers are careful in accessing how their position will look like the end of certain periods, little attention is given how they will get there through the period. The uncertainty of how a process will develop across a shorter period of time is often “eliminated” by simply choosing a longer planning time interval, what makes path dependency is one of the most often overlooked business risk types. After reviewing the origin of the problem we propose and compare seven risk measures to access path. Traditional risk measures like standard deviation of sub period cash flows fail to capture this risk type. We conclude that in most cases considering the distribution of the expected cash flow effect caused by the path dependency may offer the best method, but we may need to use several measures at the same time to include all the optimisation limits of the given firm

  5. Fluorescence confocal polarizing microscopy: Three-dimensional ...

    Indian Academy of Sciences (India)

    Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director patterns by ...

  6. Fluorescence confocal polarizing microscopy: Three-dimensional ...

    Indian Academy of Sciences (India)

    Abstract. Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director ...

  7. Wandering Scientists

    Indian Academy of Sciences (India)

    As he grew older, he began on his own to study English, modern science and history. So he brought both ancient and modern learning to assist in ..... at the hand of Maulana Azad. More than two hundred thousand citizens of Delhi had signed a peace pledge in response to. Gandhi's desire to restore complete communal ...

  8. Ocean wanderers

    NARCIS (Netherlands)

    Boer, de Marijke N.; Jones, Duncan; Jones, Hannah

    2017-01-01

    Reports of bowhead whales (Balaena mysticetus) outside the Arctic Circle are scarce. On 15 May 2016, a juvenile bowhead whale was recorded in shallow water in Mount's Bay (Cornwall, UK) much further south than the species' normal dis- tribution. Fifteen months earlier, another such sighting was made

  9. Settling the name Diomedea exulans Linnaeus, 1758 for the Wandering Albatross by neotypification.

    Science.gov (United States)

    Schodde, Richard; Tennyson, Alan J D; Groth, Jeff G; Lai, Jonas; Scofield, Paul; Steinheimer, Frank D

    2017-02-21

    On-going conflict in use of the name Diomedea exulans Linnaeus, 1758 for different taxa of the great albatrosses (Wandering Albatross complex) is resolved by neotypification, fixing the name to the large subantarctic form formerly often known as D. chionoptera Salvin, 1896. Application of all scientific names in the complex is reviewed, an annotated synonymy for the large subantarctic form is provided, available names for smaller, temperate-zone forms are listed, and unavailable and otherwise invalid names referable to the complex are identified. Syntypes of D. chionoptera and D. spadicea J.F. Gmelin, 1789 are lectotypified as well, fixing their names as synonyms of D. exulans to prevent possible disturbance to in-use names for the smaller, temperate-zone forms.

  10. Mind Wandering "Ahas" versus Mindful Reasoning: Alternative Routes to Creative Solutions

    Directory of Open Access Journals (Sweden)

    Claire M Zedelius

    2015-06-01

    Full Text Available Based on mixed results linking both mindfulness and its opposing construct mind wandering to enhanced creativity, we predicted that the relationship between mindfulness and creativity might depend on whether creative problems are approached through analytic strategy or through insight (i.e., sudden awareness of a solution. Study 1 investigated the relationship between trait mindfulness and compound remote associates problem solving as a function of participants’ self-reported approach to each problem. The results revealed a negative relationship between mindfulness and problem-solving overall. However, more detailed analysis revealed that mindfulness was associated with impaired problem solving when approaching problems with insight, but increased problem solving when using analysis. In Study 2, we manipulated participants’ problem-solving approach through instructions. We again found a negative relationship between mindfulness and creative performance in general, however, more mindful participants again performed better when instructed to approach problems analytically.

  11. A Few Remarks on the Poetics of Turbulence in Richard Powers’ Operation Wandering Soul

    Directory of Open Access Journals (Sweden)

    Jean-Yves Pellegrin

    2010-02-01

    Full Text Available Dans le roman de Richard Powers Operation Wandering Soul, la linéarité conventionnelle du récit cède le pas à une forme de discontinuité et de circularité qui évoque le mouvement imprévisible d’une turbulence. On propose de montrer ici que cette turbulence met en œuvre une nouvelle manière d’écrire et de lire les récits. Dans le roman, la turbulence apparaît toujours sous l’aspect d’une force désorganisatrice qu’il faut maîtriser, un bruit qui doit être supprimé. Cet impératif, témoin des aspirations du récit au sens et à la clôture, peut se concevoir comme l’indice de la manière dont l’ordre narratif s’efforce de soumettre toute turbulence en dissimulant son chaos sous une linéarité de façade et des dénouements postiches. Cette activité transforme le récit (et le type de lecture qu’elle induit en une sorte d’eschatologie dont Operation Wandering Soul dénonce le mensonge et la fuite en avant. Pour en combattre les effets néfastes, le roman s’emploie à perturber l’ordre narratif et à bousculer nos habitudes de lecture ; il se fait texte turbulent en conformant sa structure la plus intime à celle des systèmes non linéaires.In Richard Powers’ Operation Wandering Soul, the conventional linearity of narrative gives way to a type of discontinuity and circularity that is reminiscent of the unpredictable movement of turbulent flows. This paper suggests that such turbulence enacts a new way of writing and reading narrative. Turbulence is always described in the novel as a disruptive force that must be checked or a noise that must be silenced. This imperative, which testifies to narrative’s desire for closure and meaning, may be construed as an index of the way narrative order attempts to subdue all turbulence by covering up its proliferating chaos with perfunctory linearity and cosmetic endings. Such activity turns narrative—and the type of reading it encourages—into some kind of

  12. A new perspective on the growth pattern of the Wandering Albatross (Diomedea exulans) through DEB theory

    Science.gov (United States)

    Teixeira, Carlos M. G. L.; Sousa, Tânia; Marques, Gonçalo M.; Domingos, Tiago; Kooijman, Sebastiaan A. L. M.

    2014-11-01

    The Wandering Albatross (Diomedea exulans) and other seabirds exhibit a growing pattern that includes a period of body mass decrease before fledging. Several hypotheses have been suggested to explain it without success. We hypothesized that: 1) chicks and adults have similar metabolic traits regulating assimilation, growth and maturation; 2) there is a difference in locomotion effort between chicks and adults, and 3) chicks are exposed to a decline in food availability before fledging. This set of hypotheses allows for an energy surplus to be available and stored in reserve during the first months of development, explaining the mass recession that starts before fledging and the fact that adults keep a lower weight than fledglings, throughout the rest of their life span. To test this set of hypotheses we applied the Dynamic Energy Budget (DEB) theory. Using a small set of life-history traits and growth curves we parameterized the DEB standard model. We confirmed this set of hypotheses and estimated the pattern of decline in food availability that explains mass recession. An assessment of the daily energy intake was also performed. The implications related to that energy flux and diet composition are discussed based on current knowledge. The DEB model for the Wandering Albatross also provided estimates for the adult daily food ingested by adults (464.06 kJ kg- 1 d- 1), fasting capacity (25 d), Field Metabolic Rate (4.29 W kg- 1) and resting metabolic rate (2.87 W kg- 1). These values are consistent with the averages obtained in the field, suggesting that DEB may be useful to provide good estimations on a broader scale.

  13. Linking demographic processes and foraging ecology in wandering albatross - conservation implications.

    Science.gov (United States)

    Weimerskirch, Henri

    2018-02-24

    1.Population dynamics and foraging ecology are two fields of the population ecology that are generally studied separately. Yet foraging determines allocation processes and therefore demography. Studies on Wandering albatrosses Diomedea exulans over the past 50 years have contributed to better understand the links between population dynamics and foraging ecology. This paper reviews how these two facets of population ecology have been combined to better understand ecological processes, but also have contributed fundamentally for the conservation of this long-lived threatened species. 2.Wandering albatross research has combined a 50 year long-term study of marked individuals with two decades of tracking studies that have been initiated on this species, favoured by its large size and tameness. 3.At all stages of their life history the body mass of individuals plays a central role in allocation processes, in particular in influencing adult and juvenile survival, decisions to recruit into the population or to invest into provisioning the offspring or into maintenance. 4.Strong age-related variations in demographic parameters are observed and are linked to age-related differences in foraging distribution and efficiency. Marked sex specific differences in foraging distribution, foraging efficiency and changes in mass over life time are directly related to the strong sex specific investment in breeding and survival trajectories of the two sexes, with body mass playing a pivotal role especially in males. 5.Long-term study has allowed determining the sex specific and age specific demographic causes of population decline, and the tracking studies have been able to derive where and how these impacts occur, in particular the role of long line fisheries. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  14. Strategic Polarization.

    Science.gov (United States)

    Kalai, Adam; Kalai, Ehud

    2001-08-01

    In joint decision making, similarly minded people may take opposite positions. Consider the example of a marriage in which one spouse gives generously to charity while the other donates nothing. Such "polarization" may misrepresent what is, in actuality, a small discrepancy in preferences. It may be that the donating spouse would like to see 10% of their combined income go to charity each year, while the apparently frugal spouse would like to see 8% donated. A simple game-theoretic analysis suggests that the spouses will end up donating 10% and 0%, respectively. By generalizing this argument to a larger class of games, we provide strategic justification for polarization in many situations such as debates, shared living accommodations, and disciplining children. In some of these examples, an arbitrarily small disagreement in preferences leads to an arbitrarily large loss in utility for all participants. Such small disagreements may also destabilize what, from game-theoretic point of view, is a very stable equilibrium. Copyright 2001 Academic Press.

  15. Shortest Paths and Vehicle Routing

    DEFF Research Database (Denmark)

    Petersen, Bjørn

    This thesis presents how to parallelize a shortest path labeling algorithm. It is shown how to handle Chvátal-Gomory rank-1 cuts in a column generation context. A Branch-and-Cut algorithm is given for the Elementary Shortest Paths Problem with Capacity Constraint. A reformulation of the Vehicle R...... Routing Problem based on partial paths is presented. Finally, a practical application of finding shortest paths in the telecommunication industry is shown....

  16. Thoughts and sensations, twin galaxies of the inner space: The propensity to mind-wander relates to spontaneous sensations arising on the hands.

    Science.gov (United States)

    Michael, George A; Tapiero, Isabelle; Gálvez-García, Germán; Jacquot, Laurence

    2017-10-01

    Sensations and thoughts have been described as potentially related to self-awareness. We therefore asked whether sensations that arise in the absence of external triggers, i.e., spontaneous sensations (SPS), which were shown to relate to interoception and perception of the self, vary as a function of the individual propensity to generate spontaneous thoughts, i.e., mind-wandering. The Mind Wandering Questionnaire (MWQ) was used as a specific tool to assess the frequency and propensity to mind-wander several weeks before completing an SPS task. Correlational analyses between the MWQ score and SPS showed that greater propensity to mind-wander coincided with widespread perception of SPS, while lesser propensity to mind-wander coincided with more spatially restricted perception of SPS. The results are interpreted in light of the role of spontaneous thoughts and sensations in self-awareness. The potential psychological processes and the way they might regulate the relation between mind-wandering and the perception of SPS are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Can I get me out of my head? Exploring strategies for controlling the self-referential aspects of the mind-wandering state during reading.

    Science.gov (United States)

    Sanders, Jet G; Wang, Hao-Ting; Schooler, Jonathan; Smallwood, Jonathan

    2017-06-01

    Trying to focus on a piece of text and keep unrelated thoughts at bay can be a surprisingly futile experience. The current study explored the effects of different instructions on participants' capacity to control their mind-wandering and maximize reading comprehension, while reading. Participants were instructed to (a) enhance focus on what was read (external) or (b) enhance meta-awareness of mind-wandering (internal). To understand when these strategies were important, we induced a state of self-focus in half of our participants at the beginning of the experiment. Results replicated the negative association between mind-wandering and comprehension and demonstrated that both internal and external instructions impacted on the efficiency of reading following a period of induced self-focus. Techniques that foster meta-awareness improved task focus but did so at the detriment of reading comprehension, while promoting a deeper engagement while reading improved comprehension with no changes in reported mind-wandering. These data provide insight into how we can control mind-wandering and improve comprehension, and they underline that a state of self-focus is a condition under which they should be employed. Furthermore, these data support component process models that propose that the self-referent mental contents that arise during mind-wandering are distinguishable from those processes that interfere with comprehension.

  18. Tracking the train of thought from the laboratory into everyday life: An experience-sampling study of mind wandering across controlled and ecological contexts

    Science.gov (United States)

    McVay, Jennifer C.; Kane, Michael J.; Kwapil, Thomas R.

    2009-01-01

    In an experience-sampling study that bridged laboratory, ecological, and individual-differences approaches to mind-wandering research, 72 subjects completed an executive-control task with periodic thought probes (reported by McVay & Kane, 2009) and then carried PDAs for a week that signaled them 8 times daily to report immediately whether their thoughts were off-task. Subjects who reported more mind wandering during the laboratory task endorsed more mind-wandering experiences during everyday life (and were more likely to report worries as off-task thought content). We also conceptually replicated laboratory findings that mind wandering predicts task performance: subjects rated their daily-life performance to be impaired when they reported off-task thoughts, with greatest impairment when subjects’ mind wandering lacked meta-consciousness. The propensity to mind-wander appears to be a stable cognitive characteristic and seems to predict performance difficulties in daily life, just as it does in the laboratory. PMID:19815789

  19. Path planning in dynamic environments

    NARCIS (Netherlands)

    Berg, J.P. van den

    2007-01-01

    Path planning plays an important role in various fields of application, such as CAD design, computer games and virtual environments, molecular biology, and robotics. In its most general form, the path planning problem is formulated as finding a collision-free path for a moving entity between a start

  20. Integrating path dependency and path creation in a general understanding of path constitution

    OpenAIRE

    Meyer, Uli; Schubert, Cornelius

    2007-01-01

    Path dependency as it is described by Arthur and David portrays technological developments as historically embedded, emergent processes. In contrast, Garud and Karnøe's notion of path creation emphasises the role of strategic change and deliberate action for the development of new technologies. In this article, we integrate both concepts into a general understanding of path processes which accounts for emergent as well as deliberate modes of path constitution. In addition, we distinguish betw...

  1. Two Generations of Path Dependence

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

      Even if there is no fully articulated and generally accepted theory of Path Dependence it has eagerly been taken up across a wide range of social sciences - primarily coming from economics. Path Dependence is most of all a metaphor that offers reason to believe, that some political, social...... or economic processes have multiple possible paths of outcomes, rather than a unique path of equilibria. The selection among outcomes may depend on contingent choices or events - outcomes of path-dependent processes require a very relevant study - a perception of history....

  2. JAVA PathFinder

    Science.gov (United States)

    Mehhtz, Peter

    2005-01-01

    JPF is an explicit state software model checker for Java bytecode. Today, JPF is a swiss army knife for all sort of runtime based verification purposes. This basically means JPF is a Java virtual machine that executes your program not just once (like a normal VM), but theoretically in all possible ways, checking for property violations like deadlocks or unhandled exceptions along all potential execution paths. If it finds an error, JPF reports the whole execution that leads to it. Unlike a normal debugger, JPF keeps track of every step how it got to the defect.

  3. Path Through the Wheat

    Directory of Open Access Journals (Sweden)

    David Middleton

    2005-01-01

    Full Text Available The hillside’s tidal waves of yellow-green Break downward into full-grown stalks of wheat In which a peasant, shouldering his hoe Passes along a snaking narrow path -- A teeming place through which his hard thighs press And where his head just barely stays above The swaying grain, drunken in abundance, Farm buildings almost floating on the swells Beyond which sea gulls gliding white in air Fly down on out of sight to salty fields, Taking the channel fish off Normandy, A surfeit fit for Eden i...

  4. Path to Prosperity

    OpenAIRE

    Wolfowitz,Paul

    2006-01-01

    Paul Wolfowitz, President of the World Bank, discussed Singapore's remarkable progress along the road from poverty to prosperity which has also been discovered by many other countries in East Asia and around the world. He spoke of how each country must find its own path for people to pursue the same dreams of the chance to go to school, the security of a good job, and the ability to provide a better future for their children. Throughout the world, and importantly in the developing world, ther...

  5. Rocket Flight Path

    Directory of Open Access Journals (Sweden)

    Jamie Waters

    2014-09-01

    Full Text Available This project uses Newton’s Second Law of Motion, Euler’s method, basic physics, and basic calculus to model the flight path of a rocket. From this, one can find the height and velocity at any point from launch to the maximum altitude, or apogee. This can then be compared to the actual values to see if the method of estimation is a plausible. The rocket used for this project is modeled after Bullistic-1 which was launched by the Society of Aeronautics and Rocketry at the University of South Florida.

  6. Hamiltonian path integrals

    International Nuclear Information System (INIS)

    Prokhorov, L.V.

    1982-01-01

    Problems related to consideration of operator nonpermutability in Hamiltonian path integral (HPI) are considered in the review. Integrals are investigated using trajectories in configuration space (nonrelativistic quantum mechanics). Problems related to trajectory integrals in HPI phase space are discussed: the problem of operator nonpermutability consideration (extra terms problem) and corresponding equivalence rules; ambiguity of HPI usual recording; transition to curvilinear coordinates. Problem of quantization of dynamical systems with couplings has been studied. As in the case of canonical transformations, quantization of the systems with couplings of the first kind requires the consideration of extra terms

  7. Precessing deuteron polarization

    International Nuclear Information System (INIS)

    Sitnik, I.M.; Volkov, V.I.; Kirillov, D.A.; Piskunov, N.M.; Plis, Yu.A.

    2002-01-01

    The feasibility of the acceleration in the Nuclotron of deuterons polarized in the horizontal plane is considered. This horizontal polarization is named precessing polarization. The effects of the main magnetic field and synchrotron oscillations are included. The precessing polarization is supposed to be used in studying the polarization parameters of the elastic dp back-scattering and other experiments

  8. A Collision Detection-Based Wandering Method for Equipment Deploy Scene in Land Reclamation Area of Mining Dump

    OpenAIRE

    Ma, Juncheng; Li, Daoliang; Chen, Yingyi; Li, Li; Gao, Fei; Zhang, Lingxian

    2011-01-01

    Part 1: Decision Support Systems, Intelligent Systems and Artificial Intelligence Applications; International audience; Aiming at developing a simple and efficient collision detection method to support the wandering in equipment deploy scene in land reclamation area of mining dump. This paper presents an efficient algorithm for collision detection in the waste dump land reclamation equipment deploy scene using a bounding volume nestification which consists of an oriented bounding boxes (OBBs)...

  9. "A combined experimental and individual-differences investigation into mind wandering during a video lecture": Correction to Kane et al. (2017).

    Science.gov (United States)

    2018-04-01

    Reports an error in "A combined experimental and individual-differences investigation into mind wandering during a video lecture" by Michael J. Kane, Bridget A. Smeekens, Claudia C. von Bastian, John H. Lurquin, Nicholas P. Carruth and Akira Miyake ( Journal of Experimental Psychology: General , 2017[Nov], Vol 146[11], 1649-1674). In the article, the legends for Figure 2 and Figure 4 were erroneous. The correct figures are included in the errata. The online version of this article has been corrected. (The following abstract of the original article appeared in record 2017-48585-001.) A combined experimental-correlational study with a diverse sample (N = 182) from 2 research sites tested a set of 5 a priori hypotheses about mind wandering and learning, using a realistic video lecture on introductory statistics. Specifically, the study examined whether students' vulnerability to mind wandering during the lecture would predict learning from, and situational interest in, the video and also whether longhand note-taking would help reduce mind wandering, at least for some students. One half of the participants took notes during the video, and all were subsequently tested on lecture content without notes. Regression and mediation analyses indicated that (a) several individual-differences variables (e.g., pretest score, prior math interest, classroom media multitasking habits) uniquely predicted in-lecture mind wandering frequency; (b) although the note-taking manipulation did not reduce mind wandering at the group level, note-taking still reduced mind wandering for some individuals (i.e., those with lower prior knowledge and those who took notes of high quality and quantity); (c) mind wandering uniquely predicted both learning (posttest) and situational interest outcomes above and beyond all other individual-differences variables; (d) moreover, mind wandering significantly mediated the effects of several individual differences; and, finally, (e) not all types of mind

  10. World nuclear energy paths

    International Nuclear Information System (INIS)

    Connolly, T.J.; Hansen, U.; Jaek, W.; Beckurts, K.H.

    1979-01-01

    In examing the world nuclear energy paths, the following assumptions were adopted: the world economy will grow somewhat more slowly than in the past, leading to reductions in electricity demand growth rates; national and international political impediments to the deployment of nuclear power will gradually disappear over the next few years; further development of nuclear power will proceed steadily, without serious interruption but with realistic lead times for the introduction of advanced technologies. Given these assumptions, this paper attempts a study of possible world nuclear energy developments, disaggregated on a regional and national basis. The scenario technique was used and a few alternative fuel-cycle scenarios were developed. Each is an internally consistent model of technically and economically feasible paths to the further development of nuclear power in an aggregate of individual countries and regions of the world. The main purpose of this modeling exercise was to gain some insight into the probable international locations of reactors and other nuclear facilities, the future requirements for uranium and for fuel-cycle services, and the problems of spent-fuel storage and waste management. The study also presents an assessment of the role that nuclear power might actually play in meeting future world energy demand

  11. Polare maskuliniteter

    Directory of Open Access Journals (Sweden)

    Marit Anne Hauan

    2012-05-01

    Full Text Available In this paper my aim is to read and understand the journal of Gerrit de Veer from the last journey of William Barents to the Arctic Regions in 1596 and the journal of captain Junge on his hunting trip from Tromsø to Svalbard in 1834.It is nearly 240 years between this to voyages. The first journal is known as the earliest report from the arctic era. Gerrit de Veer adds instructive copper engravings to his text and give us insight in the crews meeting with this new land. Captain Junges journal is found together with his dead crew in a house in a fjord nearby Ny-Ålesund and has no drawings, but word. Both of these journals may be read as sources of the knowledge and understanding of the polar region. They might also unveil the ideas of how to deal with and survive under the challenges that is given. In addition one can ask if the sources can tell us more about how men describe their challenges. Can the way they expressed themselves in the journals give us an understanding of masculinity? And not least help us to create good questions of the change in the ideas of masculinities which is said to follow the change in understanding of the wilderness.

  12. Micromechanical properties of strain-sensitive lyriform organs of a wandering spider (Cupiennius salei).

    Science.gov (United States)

    Young, Seth L; Chyasnavichyus, Marius; Barth, Friedrich G; Zlotnikov, Igor; Politi, Yael; Tsukruk, Vladimir V

    2016-09-01

    Highly sensitive lyriform organs located on the legs of the wandering spider Cupiennius salei allow the spider to detect nanometer-scale strains in the exoskeleton resulting from locomotion or substrate vibrations. Morphological features of the lyriform organs result in their specialization and selective sensitivity to specific mechanical stimuli, which make them interesting for bioinspired strain sensors. Here we utilize atomic force microscopy (AFM)-based force spectroscopy to probe nano-scale mechanical properties of the covering membrane of two lyriform organs found on Cupiennius salei: the vibration sensitive metatarsal lyriform organ (HS10) and the proprioreceptive tibial lyriform organ (HS8). Force distance curves (FDCs) obtained from AFM measurements displayed characteristic multi-layer structure behavior, with calculated elastic moduli ranging from 150MPa to 500MPa for different regions and indentation depths. In addition, we probed the lyriform organs with a large radius tip, which allowed for probing structural deformation by the application of high forces and large scale deformations without damaging the surface. The viscoelastic behavior of the sensor materials observed in this probing suggests mechanical relaxation times potentially playing a role in the time-dependent behavior of the lyriform organs. Highly sensitive lyriform organs located on the legs of the wandering spider Cupiennius salei allow the spider to detect nanometer-scale strains in the exoskeleton resulting from locomotion or substrate vibrations. Morphological features of the lyriform organs result in their specialization and selective sensitivity to specific mechanical stimuli, which make them an interesting for bioinspired strain sensors. Here we utilize atomic force microscopy (AFM)-based force spectroscopy to probe nano-scale mechanical properties of the covering membrane of two lyriform organs found on Cupiennius salei: the vibration sensitive metatarsal lyriform organ (HS10) and

  13. innovation path exploration

    Directory of Open Access Journals (Sweden)

    Li Jian

    2016-01-01

    Full Text Available The world has entered the information age, all kinds of information technologies such as cloud technology, big data technology are in rapid development, and the “Internet plus” appeared. The main purpose of “Internet plus” is to provide an opportunity for the further development of the enterprise, the enterprise technology, business and other aspects of factors combine. For enterprises, grasp the “Internet plus” the impact of the market economy will undoubtedly pave the way for the future development of enterprises. This paper will be on the innovation path of the enterprise management “Internet plus” era tied you study, hope to be able to put forward some opinions and suggestions.

  14. Brief quiet ego contemplation reduces oxidative stress and mind-wandering.

    Science.gov (United States)

    Wayment, Heidi A; Collier, Ann F; Birkett, Melissa; Traustadóttir, Tinna; Till, Robert E

    2015-01-01

    Excessive self-concern increases perceptions of threat and defensiveness. In contrast, fostering a more inclusive and expanded sense of self can reduce stress and improve well-being. We developed and tested a novel brief intervention designed to strengthen a student's compassionate self-identity, an identity that values balance and growth by reminding them of four quiet ego characteristics: detached awareness, inclusive identity, perspective taking, and growth. Students (N = 32) in their first semester of college who reported greater self-protective (e.g., defensive) goals in the first 2 weeks of the semester were invited to participate in the study. Volunteers were randomly assigned to one of three conditions: quiet ego contemplation (QEC), QEC with virtual reality (VR) headset (QEC-VR), and control. Participants came to the lab three times to engage in a 15-min exercise in a 30-days period. The 15-min QEC briefly described each quiet ego characteristic followed by a few minutes time to reflect on what that characteristic meant to them. Those in the QEC condition reported improved quiet ego characteristics and pluralistic thinking, decreases in a urinary marker of oxidative stress, and reduced mind-wandering on a cognitive task. Contrary to expectation, participants who wore the VR headsets while listening to the QEC demonstrated the least improvement. Results suggest that a brief intervention that reduces self-focus and strengthens a more compassionate self-view may offer an additional resource that individuals can use in their everyday lives.

  15. A Wandering Mind Does Not Stray Far from Home: The Value of Metacognition in Distant Search

    Science.gov (United States)

    Kudesia, Ravi S.; Baer, Markus; Elfenbein, Hillary Anger

    2015-01-01

    When faced with a problem, how do individuals search for potential solutions? In this article, we explore the cognitive processes that lead to local search (i.e., identifying options closest to existing solutions) and distant search (i.e., identifying options of a qualitatively different nature than existing solutions). We suggest that mind wandering is likely to lead to local search because it operates by spreading activation from initial ideas to closely associated ideas. This reduces the likelihood of accessing a qualitatively different solution. However, instead of getting lost in thought, individuals can also step back and monitor their thoughts from a detached perspective. Such mindful metacognition, we suggest, is likely to lead to distant search because it redistributes activation away from initial ideas to other, less strongly associated, ideas. This hypothesis was confirmed across two studies. Thus, getting lost in thoughts is helpful when one is on the right track and needs only a local search whereas stepping back from thoughts is helpful when one needs distant search to produce a change in perspective. PMID:25974164

  16. A wandering mind does not stray far from home: the value of metacognition in distant search.

    Directory of Open Access Journals (Sweden)

    Ravi S Kudesia

    Full Text Available When faced with a problem, how do individuals search for potential solutions? In this article, we explore the cognitive processes that lead to local search (i.e., identifying options closest to existing solutions and distant search (i.e., identifying options of a qualitatively different nature than existing solutions. We suggest that mind wandering is likely to lead to local search because it operates by spreading activation from initial ideas to closely associated ideas. This reduces the likelihood of accessing a qualitatively different solution. However, instead of getting lost in thought, individuals can also step back and monitor their thoughts from a detached perspective. Such mindful metacognition, we suggest, is likely to lead to distant search because it redistributes activation away from initial ideas to other, less strongly associated, ideas. This hypothesis was confirmed across two studies. Thus, getting lost in thoughts is helpful when one is on the right track and needs only a local search whereas stepping back from thoughts is helpful when one needs distant search to produce a change in perspective.

  17. Demographic Responses to Oxidative Stress and Inflammation in the Wandering Albatross (Diomedea exulans).

    Science.gov (United States)

    Costantini, David; Goutte, Aurelie; Barbraud, Christophe; Faivre, Bruno; Sorci, Gabriele; Weimerskirch, Henri; Delord, Karine; Chastel, Olivier

    2015-01-01

    One of the major challenges in ecological research is the elucidation of physiological mechanisms that underlie the demographic traits of wild animals. We have assessed whether a marker of plasma oxidative stress (TBARS) and plasma haptoglobin (protein of the acute inflammatory phase response) measured at time t predict five demographic parameters (survival rate, return rate to the breeding colony, breeding probability, hatching and fledging success) in sexually mature wandering albatrosses over the next four years (Diomedea exulans) using a five-year individual-based dataset. Non-breeder males, but not females, having higher TBARS at time t had reduced future breeding probabilities; haptoglobin was not related to breeding probability. Neither TBARS nor haptoglobin predicted future hatching or fledging success. Haptoglobin had a marginally positive effect on female survival rate, while TBARS had a marginally negative effect on return rate. Our findings do not support the role for oxidative stress as a constraint of future reproductive success in the albatross. However, our data point to a potential mechanism underlying some aspects of reproductive senescence and survival. Our results also highlight that the study of the consequences of oxidative stress should consider the life-cycle stage of an individual and its reproductive history.

  18. Classifying the wandering mind: revealing the affective content of thoughts during task-free rest periods.

    Science.gov (United States)

    Tusche, Anita; Smallwood, Jonathan; Bernhardt, Boris C; Singer, Tania

    2014-08-15

    Many powerful human emotional thoughts are generated in the absence of a precipitating event in the environment. Here, we tested whether we can decode the valence of internally driven, self-generated thoughts during task-free rest based on neural similarities with task-related affective mental states. We acquired functional magnetic resonance imaging (fMRI) data while participants generated positive and negative thoughts as part of an attribution task (Session A) and while they reported the occurrence of comparable mental states during task-free rest periods (Session B). With the use of multivariate pattern analyses (MVPA), we identified response patterns in the medial orbitofrontal cortex (mOFC) that encode the affective content of thoughts that are generated in response to an external experimental cue. Importantly, these task driven response patterns reliably predicted the occurrence of affective thoughts generated during unconstrained rest periods recorded one week apart. This demonstrates that at least certain elements of task-cued and task-free affective experiences rely on a common neural code. Furthermore, our findings reveal the role that the mOFC plays in determining the affective tone of unconstrained thoughts. More generally, our results suggest that MVPA is an important methodological tool for attempts to understand unguided subject driven mental states such as mind-wandering and daydreaming based on neural similarities with task-based experiences. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Multiscale permutation entropy analysis of laser beam wandering in isotropic turbulence

    Science.gov (United States)

    Olivares, Felipe; Zunino, Luciano; Gulich, Damián; Pérez, Darío G.; Rosso, Osvaldo A.

    2017-10-01

    We have experimentally quantified the temporal structural diversity from the coordinate fluctuations of a laser beam propagating through isotropic optical turbulence. The main focus here is on the characterization of the long-range correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. To fulfill this goal, a laboratory-controlled experiment was conducted in which coordinate fluctuations of the laser beam were recorded at a sufficiently high sampling rate for a wide range of turbulent conditions. Horizontal and vertical displacements of the laser beam centroid were subsequently analyzed by implementing the symbolic technique based on ordinal patterns to estimate the well-known permutation entropy. We show that the permutation entropy estimations at multiple time scales evidence an interplay between different dynamical behaviors. More specifically, a crossover between two different scaling regimes is observed. We confirm a transition from an integrated stochastic process contaminated with electronic noise to a fractional Brownian motion with a Hurst exponent H =5 /6 as the sampling time increases. Besides, we are able to quantify, from the estimated entropy, the amount of electronic noise as a function of the turbulence strength. We have also demonstrated that these experimental observations are in very good agreement with numerical simulations of noisy fractional Brownian motions with a well-defined crossover between two different scaling regimes.

  20. A wandering mind does not stray far from home: the value of metacognition in distant search.

    Science.gov (United States)

    Kudesia, Ravi S; Baer, Markus; Elfenbein, Hillary Anger

    2015-01-01

    When faced with a problem, how do individuals search for potential solutions? In this article, we explore the cognitive processes that lead to local search (i.e., identifying options closest to existing solutions) and distant search (i.e., identifying options of a qualitatively different nature than existing solutions). We suggest that mind wandering is likely to lead to local search because it operates by spreading activation from initial ideas to closely associated ideas. This reduces the likelihood of accessing a qualitatively different solution. However, instead of getting lost in thought, individuals can also step back and monitor their thoughts from a detached perspective. Such mindful metacognition, we suggest, is likely to lead to distant search because it redistributes activation away from initial ideas to other, less strongly associated, ideas. This hypothesis was confirmed across two studies. Thus, getting lost in thoughts is helpful when one is on the right track and needs only a local search whereas stepping back from thoughts is helpful when one needs distant search to produce a change in perspective.

  1. Demographic Responses to Oxidative Stress and Inflammation in the Wandering Albatross (Diomedea exulans.

    Directory of Open Access Journals (Sweden)

    David Costantini

    Full Text Available One of the major challenges in ecological research is the elucidation of physiological mechanisms that underlie the demographic traits of wild animals. We have assessed whether a marker of plasma oxidative stress (TBARS and plasma haptoglobin (protein of the acute inflammatory phase response measured at time t predict five demographic parameters (survival rate, return rate to the breeding colony, breeding probability, hatching and fledging success in sexually mature wandering albatrosses over the next four years (Diomedea exulans using a five-year individual-based dataset. Non-breeder males, but not females, having higher TBARS at time t had reduced future breeding probabilities; haptoglobin was not related to breeding probability. Neither TBARS nor haptoglobin predicted future hatching or fledging success. Haptoglobin had a marginally positive effect on female survival rate, while TBARS had a marginally negative effect on return rate. Our findings do not support the role for oxidative stress as a constraint of future reproductive success in the albatross. However, our data point to a potential mechanism underlying some aspects of reproductive senescence and survival. Our results also highlight that the study of the consequences of oxidative stress should consider the life-cycle stage of an individual and its reproductive history.

  2. An investigation of the neural substrates of mind wandering induced by viewing traditional Chinese landscape paintings

    Science.gov (United States)

    Wang, Tingting; Mo, Lei; Vartanian, Oshin; Cant, Jonathan S.; Cupchik, Gerald

    2015-01-01

    The present study was conducted to investigate whether the calming effect induced by viewing traditional Chinese landscape paintings would make disengagement from that mental state more difficult, as measured by performance on a cognitive control task. In Experiment 1 we examined the subjective experience of viewing traditional Chinese landscape paintings vs. realistic oil landscape paintings in a behavioral study. Our results confirmed that, as predicted, traditional Chinese landscape paintings induce greater levels of relaxation and mind wandering and lower levels of object-oriented absorption and recognition, compared to realistic oil landscape paintings. In Experiment 2 we used functional Magnetic Resonance Imaging to explore the behavioral and neural effects of viewing traditional Chinese landscape paintings on a task requiring cognitive control (i.e., the flanker task)—administered immediately following exposure to paintings. Contrary to our prediction, the behavioral data demonstrated that compared to realistic oil landscape paintings, exposure to traditional Chinese landscape paintings had no effect on performance on the flanker task. However, the neural data demonstrated an interaction effect such that there was greater activation in the inferior parietal cortex and the superior frontal gyrus on incongruent compared with congruent flanker trials when participants switched from viewing traditional Chinese landscape paintings to the flanker task than when they switched from realistic oil landscape paintings. These results suggest that switching from traditional Chinese landscape paintings placed greater demands on the brain’s attention and working memory networks during the flanker task than did switching from realistic oil landscape paintings. PMID:25610386

  3. An investigation of the neural substrates of mind wandering induced by viewing traditional Chinese landscape paintings.

    Science.gov (United States)

    Wang, Tingting; Mo, Lei; Vartanian, Oshin; Cant, Jonathan S; Cupchik, Gerald

    2014-01-01

    The present study was conducted to investigate whether the calming effect induced by viewing traditional Chinese landscape paintings would make disengagement from that mental state more difficult, as measured by performance on a cognitive control task. In Experiment 1 we examined the subjective experience of viewing traditional Chinese landscape paintings vs. realistic oil landscape paintings in a behavioral study. Our results confirmed that, as predicted, traditional Chinese landscape paintings induce greater levels of relaxation and mind wandering and lower levels of object-oriented absorption and recognition, compared to realistic oil landscape paintings. In Experiment 2 we used functional Magnetic Resonance Imaging to explore the behavioral and neural effects of viewing traditional Chinese landscape paintings on a task requiring cognitive control (i.e., the flanker task)-administered immediately following exposure to paintings. Contrary to our prediction, the behavioral data demonstrated that compared to realistic oil landscape paintings, exposure to traditional Chinese landscape paintings had no effect on performance on the flanker task. However, the neural data demonstrated an interaction effect such that there was greater activation in the inferior parietal cortex and the superior frontal gyrus on incongruent compared with congruent flanker trials when participants switched from viewing traditional Chinese landscape paintings to the flanker task than when they switched from realistic oil landscape paintings. These results suggest that switching from traditional Chinese landscape paintings placed greater demands on the brain's attention and working memory networks during the flanker task than did switching from realistic oil landscape paintings.

  4. Path integral in Snyder space

    International Nuclear Information System (INIS)

    Mignemi, S.; Štrajn, R.

    2016-01-01

    The definition of path integrals in one- and two-dimensional Snyder space is discussed in detail both in the traditional setting and in the first-order formalism of Faddeev and Jackiw. - Highlights: • The definition of the path integral in Snyder space is discussed using phase space methods. • The same result is obtained in the first-order formalism of Faddeev and Jackiw. • The path integral formulation of the two-dimensional Snyder harmonic oscillator is outlined.

  5. Interactive cutting path analysis programs

    Science.gov (United States)

    Weiner, J. M.; Williams, D. S.; Colley, S. R.

    1975-01-01

    The operation of numerically controlled machine tools is interactively simulated. Four programs were developed to graphically display the cutting paths for a Monarch lathe, Cintimatic mill, Strippit sheet metal punch, and the wiring path for a Standard wire wrap machine. These programs are run on a IMLAC PDS-ID graphic display system under the DOS-3 disk operating system. The cutting path analysis programs accept input via both paper tape and disk file.

  6. Path integral in Snyder space

    Energy Technology Data Exchange (ETDEWEB)

    Mignemi, S., E-mail: smignemi@unica.it [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy); Štrajn, R. [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy)

    2016-04-29

    The definition of path integrals in one- and two-dimensional Snyder space is discussed in detail both in the traditional setting and in the first-order formalism of Faddeev and Jackiw. - Highlights: • The definition of the path integral in Snyder space is discussed using phase space methods. • The same result is obtained in the first-order formalism of Faddeev and Jackiw. • The path integral formulation of the two-dimensional Snyder harmonic oscillator is outlined.

  7. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  8. Sustainable Energy Path

    Directory of Open Access Journals (Sweden)

    Hiromi Yamamoto

    2005-12-01

    Full Text Available The uses of fossil fuels cause not only the resources exhaustion but also the environmental problems such as global warming. The purposes of this study are to evaluate paths toward sustainable energy systems and roles of each renewable. In order to realize the purposes, the authors developed the global land use and energy model that figured the global energy supply systems in the future considering the cost minimization. Using the model, the authors conducted a simulation in C30R scenario, which is a kind of strict CO2 emission limit scenarios and reduced CO2 emissions by 30% compared with Kyoto protocol forever scenario, and obtained the following results. In C30R scenario bioenergy will supply 33% of all the primary energy consumption. However, wind and photovoltaic will supply 1.8% and 1.4% of all the primary energy consumption, respectively, because of the limits of power grid stability. The results imply that the strict limits of CO2 emissions are not sufficient to achieve the complete renewable energy systems. In order to use wind and photovoltaic as major energy resources, we need not only to reduce the plant costs but also to develop unconventional renewable technologies.

  9. Errância e normalização social: um estudo sobre andarilhos de estrada Errantes y normalización social: un estudio sobre andariegos de carretera Wandering and social normalization: a study about highway wanderers

    Directory of Open Access Journals (Sweden)

    Eurípedes Costa do Nascimento

    2009-12-01

    Full Text Available O nomadismo contemporâneo associado à migração, pobreza, desemprego e desfiliação social é uma característica marcante de nosso tempo e se expressa com maior radicalidade no fenômeno da errância, compreendida por uma perambulação a pé do indivíduo pelas rodovias, sem rumo certo e destino definido. O presente artigo tem por objetivo analisar a relação entre a errância e a normalização social, tendo como foco de análise o caso dos andarilhos de estrada.El nomadismo contemporáneo articulado con la migración, pobreza, desempleo y desafiliación social es una característica común de nuestro tiempo y puede ser percibido radicalmente en el fenómeno de los errantes, sujetos que son conocidos por caminaren a pie por las carreteras, sin rumbo cierto y destino definido. Ese artículo procura analizar la relación entre los errantes y la normalización social eligiendo como foco de análisis el caso de los andariegos de carretera.The contemporary nomadic life related to migration, poverty, unemployment and social disaffiliation is a common characteristic of our time and it can be seen radically in the wandering phenomenon understood as a displacement on foot of the individual through the highways without certain course and no definite destination. The present paper aims to analyze the relation between the wandering and the social normalization being the highway wanderers the main analysis focus.

  10. Path integrals as discrete sums

    Science.gov (United States)

    Bitar, Khalil; Khuri, N. N.; Ren, H. C.

    1991-08-01

    We present a new formulation of Feynman's path integral, based on Voronin's theorems on the universality of the Riemann zeta function. The result is a discrete sum over ``paths,'' each given by a zeta function. A new measure which leads to the correct quantum mechanics is explicitly given.

  11. On Minc's sheltered middle path

    OpenAIRE

    Repovš, Dušan; Rosicki, Witold; Virk, Žiga; Zastrow, Andreas

    2012-01-01

    This paper shows that a construction, which was introduced by Piotr Minc in connection with a problem that came from Helly type theorems and that allows to replace three PL-arcs with a "sheltered middle path", can in the case of general (non-PL) paths result in the topologist's sine curve.

  12. On Hilbert space of paths

    International Nuclear Information System (INIS)

    Exner, P.; Kolerov, G.I.

    1980-01-01

    A Hilbert space of paths, the elements of which are determined by trigonometric series, was proposed and used recently by Truman. This space is shown to consist precisely of all absolutely continuous paths ending in the origin with square-integrable derivatives

  13. Probabilistic Connections for Bidirectional Path Tracing

    OpenAIRE

    Popov, Stefan; Ramamoorthi, Ravi; Durand, Fredo; Drettakis, George

    2015-01-01

    International audience; Bidirectional Path Tracing Probabilistic Connections for Bidirectional Path Tracing Figure 1: Our Probabilistic Connections for Bidirectional Path Tracing approach importance samples connections to an eye sub-path, and greatly reduces variance, by considering and reusing multiple light sub-paths at once. Our approach (right) achieves much higher quality than bidirectional path-tracing on the left for the same computation time (~8.4 min).. Abstract Bidirectional path tr...

  14. Hard paths, soft paths or no paths? Cross-cultural perceptions of water solutions

    Science.gov (United States)

    Wutich, A.; White, A. C.; White, D. D.; Larson, K. L.; Brewis, A.; Roberts, C.

    2014-01-01

    In this study, we examine how development status and water scarcity shape people's perceptions of "hard path" and "soft path" water solutions. Based on ethnographic research conducted in four semi-rural/peri-urban sites (in Bolivia, Fiji, New Zealand, and the US), we use content analysis to conduct statistical and thematic comparisons of interview data. Our results indicate clear differences associated with development status and, to a lesser extent, water scarcity. People in the two less developed sites were more likely to suggest hard path solutions, less likely to suggest soft path solutions, and more likely to see no path to solutions than people in the more developed sites. Thematically, people in the two less developed sites envisioned solutions that involve small-scale water infrastructure and decentralized, community-based solutions, while people in the more developed sites envisioned solutions that involve large-scale infrastructure and centralized, regulatory water solutions. People in the two water-scarce sites were less likely to suggest soft path solutions and more likely to see no path to solutions (but no more likely to suggest hard path solutions) than people in the water-rich sites. Thematically, people in the two water-rich sites seemed to perceive a wider array of unrealized potential soft path solutions than those in the water-scarce sites. On balance, our findings are encouraging in that they indicate that people are receptive to soft path solutions in a range of sites, even those with limited financial or water resources. Our research points to the need for more studies that investigate the social feasibility of soft path water solutions, particularly in sites with significant financial and natural resource constraints.

  15. Dreaming as mind wandering: evidence from functional neuroimaging and first-person content reports

    Directory of Open Access Journals (Sweden)

    Kieran C. R. Fox

    2013-07-01

    Full Text Available Isolated reports have long suggested a similarity in content and thought processes across mind wandering (MW during waking, and dream mentation during sleep. This overlap has encouraged speculation that both ‘daydreaming’ and dreaming may engage similar brain mechanisms. To explore this possibility, we systematically examined published first-person experiential reports of MW and dreaming and found many similarities: in both states, content is largely audiovisual and emotional, follows loose narratives tinged with fantasy, is strongly related to current concerns, draws on long-term memory, and simulates social interactions. Both states are also characterized by a relative lack of meta-awareness. To relate first-person reports to neural evidence, we compared meta-analytic data from numerous functional neuroimaging (PET, fMRI studies of the default mode network (DMN, with high chances of MW and rapid eye movement (REM sleep (with high chances of dreaming. Our findings show large overlaps in activation patterns of cortical regions: similar to MW/DMN activity, dreaming and REM sleep activate regions implicated in self-referential thought and memory, including medial prefrontal cortex (PFC, medial temporal lobe structures, and posterior cingulate. Conversely, in REM sleep numerous PFC executive regions are deactivated, even beyond levels seen during waking MW. We argue that dreaming can be understood as an ‘intensified’ version of waking MW: though the two share many similarities, dreams tend to be longer, more visual and immersive, and to more strongly recruit numerous key hubs of the DMN. Further, whereas MW recruits fewer PFC regions than goal-directed thought, dreaming appears to be characterized by an even deeper quiescence of PFC regions involved in cognitive control and metacognition, with a corresponding lack of insight and meta-awareness. We suggest, then, that dreaming amplifies the same features that distinguish MW from goal

  16. Prediction of Mind-Wandering with Electroencephalogram and Non-linear Regression Modeling.

    Science.gov (United States)

    Kawashima, Issaku; Kumano, Hiroaki

    2017-01-01

    Mind-wandering (MW), task-unrelated thought, has been examined by researchers in an increasing number of articles using models to predict whether subjects are in MW, using numerous physiological variables. However, these models are not applicable in general situations. Moreover, they output only binary classification. The current study suggests that the combination of electroencephalogram (EEG) variables and non-linear regression modeling can be a good indicator of MW intensity. We recorded EEGs of 50 subjects during the performance of a Sustained Attention to Response Task, including a thought sampling probe that inquired the focus of attention. We calculated the power and coherence value and prepared 35 patterns of variable combinations and applied Support Vector machine Regression (SVR) to them. Finally, we chose four SVR models: two of them non-linear models and the others linear models; two of the four models are composed of a limited number of electrodes to satisfy model usefulness. Examination using the held-out data indicated that all models had robust predictive precision and provided significantly better estimations than a linear regression model using single electrode EEG variables. Furthermore, in limited electrode condition, non-linear SVR model showed significantly better precision than linear SVR model. The method proposed in this study helps investigations into MW in various little-examined situations. Further, by measuring MW with a high temporal resolution EEG, unclear aspects of MW, such as time series variation, are expected to be revealed. Furthermore, our suggestion that a few electrodes can also predict MW contributes to the development of neuro-feedback studies.

  17. An investigation of the neural substrates of mind wandering induced by viewing traditional Chinese landscape paintings

    Directory of Open Access Journals (Sweden)

    Tingting eWang

    2015-01-01

    Full Text Available The present study was conducted to investigate whether the calming effect induced by viewing traditional Chinese landscape paintings would make disengagement from that mental state more difficult, as measured by performance on a cognitive control task. In Experiment 1 we examined the subjective experience of viewing traditional Chinese landscape paintings vs. realistic oil landscape paintings in a behavioral study. Our results confirmed that, as predicted, traditional Chinese landscape paintings induce greater levels of relaxation and mind wandering and lower levels of object-oriented absorption and recognition, compared to realistic oil landscape paintings. In Experiment 2 we used functional Magnetic Resonance Imaging (fMRI to explore the behavioural and neural effects of viewing traditional Chinese landscape paintings on a task requiring cognitive control (i.e., the flanker task—administered immediately following exposure to paintings. Contrary to our prediction, the behavioural data demonstrated that compared to realistic oil landscape paintings, exposure to traditional Chinese landscape paintings had no effect on performance on the flanker task. However, the neural data demonstrated an interaction effect such that there was greater activation in the inferior parietal cortex (IPC and the superior frontal gyrus (SFG on incongruent compared with congruent flanker trials when participants switched from viewing traditional Chinese landscape paintings to the flanker task than when they switched from realistic oil landscape paintings. These results suggest that switching from traditional Chinese landscape paintings placed greater demands on the brain’s attention and working memory networks during the flanker task than did switching from realistic oil landscape paintings.

  18. Small-scale dispersal and survival in a long-lived seabird, the wandering albatross.

    Science.gov (United States)

    Gauthier, Gilles; Milot, Emmanuel; Weimerskirch, Henri

    2010-07-01

    1. Dispersal is a fundamental but still poorly known process in population dynamics and several hypotheses have been proposed to explain its patterns. We studied natal and breeding dispersal and survival in a long-lived seabird, the wandering albatross (Diomedea exulans L.), and examined several hypotheses concerning dispersal patterns in birds. 2. We applied multi-state capture-recapture models to a 36-year data set (1969-2004) collected at three albatross colonies on Ile de Possession, Crozet Islands. Because the species has biennial reproduction, we introduced unobservable states in the model to account for the absence of individuals in those years. 3. Adults were highly faithful to their nesting colony but colony fidelity, as well as survival rate, differed slightly among colonies (fidelity ranged from 0.957 to 0.977). Breeding fidelity was highest in the colony where survival was lowest and individuals were not more likely to change colony following a failed breeding attempt than after a successful one. The colony that attracted most dispersers had the lowest density of nesting birds. 4. Philopatry (the probability that young return to breed at a birth site) was generally high but variable among colonies (ranging from 0.70 to 0.92), and survival of young differed little. Philopatry was highest in the largest colony, where the availability of potential mates was presumably greatest. However, among dispersing individuals, the colony that had the lowest density of nesting individuals, not the largest colony, attracted the most recruits. 5. Although size of the colony influenced the decision to stay or to leave in young, density was most influential in the selection of a new colony among both adult and young dispersers. Our results support the hypothesis that philopatry is the strategy favoured by most recruits and that conspecific attraction can explain variation in the level of philopatry among colonies but not settlement patterns among dispersing individuals.

  19. Dreaming as mind wandering: evidence from functional neuroimaging and first-person content reports.

    Science.gov (United States)

    Fox, Kieran C R; Nijeboer, Savannah; Solomonova, Elizaveta; Domhoff, G William; Christoff, Kalina

    2013-01-01

    Isolated reports have long suggested a similarity in content and thought processes across mind wandering (MW) during waking, and dream mentation during sleep. This overlap has encouraged speculation that both "daydreaming" and dreaming may engage similar brain mechanisms. To explore this possibility, we systematically examined published first-person experiential reports of MW and dreaming and found many similarities: in both states, content is largely audiovisual and emotional, follows loose narratives tinged with fantasy, is strongly related to current concerns, draws on long-term memory, and simulates social interactions. Both states are also characterized by a relative lack of meta-awareness. To relate first-person reports to neural evidence, we compared meta-analytic data from numerous functional neuroimaging (PET, fMRI) studies of the default mode network (DMN, with high chances of MW) and rapid eye movement (REM) sleep (with high chances of dreaming). Our findings show large overlaps in activation patterns of cortical regions: similar to MW/DMN activity, dreaming and REM sleep activate regions implicated in self-referential thought and memory, including medial prefrontal cortex (PFC), medial temporal lobe structures, and posterior cingulate. Conversely, in REM sleep numerous PFC executive regions are deactivated, even beyond levels seen during waking MW. We argue that dreaming can be understood as an "intensified" version of waking MW: though the two share many similarities, dreams tend to be longer, more visual and immersive, and to more strongly recruit numerous key hubs of the DMN. Further, whereas MW recruits fewer PFC regions than goal-directed thought, dreaming appears to be characterized by an even deeper quiescence of PFC regions involved in cognitive control and metacognition, with a corresponding lack of insight and meta-awareness. We suggest, then, that dreaming amplifies the same features that distinguish MW from goal-directed waking thought.

  20. Brief quiet ego contemplation reduces oxidative stress and mind-wandering

    Directory of Open Access Journals (Sweden)

    Heidi A. Wayment

    2015-09-01

    Full Text Available Excessive self-concern increases perceptions of threat and defensiveness. In contrast, fostering a more inclusive and expanded sense of self can reduce stress and improve well-being. We developed and tested a novel brief intervention designed to strengthen a student’s compassionate self-identity, an identity that values balance and growth by reminding them of four quiet ego characteristics: detached awareness, inclusive identity, perspective taking, and growth. Students (N = 32 in their first semester of college who reported greater self-protective (e.g., defensive goals in the first two weeks of the semester were invited to participate in the study. Volunteers were randomly assigned to one of three conditions: quiet ego contemplation (QEC, QEC with virtual reality headset (QEC-VR, and control. Participants came to the lab three times to engage in a 15-minute exercise in a 30-day period. The 15-minute Quiet Ego Contemplation (QEC briefly described each quiet ego characteristic followed by a few minutes time to reflect on what that characteristic meant to them. Those in the QEC condition reported improved quiet ego characteristics and pluralistic thinking, decreases in a urinary marker of oxidative stress, and reduced mind-wandering on a cognitive task. Contrary to expectation, participants who wore the VR headsets while listening to the QEC demonstrated the least improvement. Results suggest that a brief intervention that reduces self-focus and strengthens a more compassionate self-view may offer an additional resource that individuals can use in their everyday lives.

  1. Prediction of Mind-Wandering with Electroencephalogram and Non-linear Regression Modeling

    Directory of Open Access Journals (Sweden)

    Issaku Kawashima

    2017-07-01

    Full Text Available Mind-wandering (MW, task-unrelated thought, has been examined by researchers in an increasing number of articles using models to predict whether subjects are in MW, using numerous physiological variables. However, these models are not applicable in general situations. Moreover, they output only binary classification. The current study suggests that the combination of electroencephalogram (EEG variables and non-linear regression modeling can be a good indicator of MW intensity. We recorded EEGs of 50 subjects during the performance of a Sustained Attention to Response Task, including a thought sampling probe that inquired the focus of attention. We calculated the power and coherence value and prepared 35 patterns of variable combinations and applied Support Vector machine Regression (SVR to them. Finally, we chose four SVR models: two of them non-linear models and the others linear models; two of the four models are composed of a limited number of electrodes to satisfy model usefulness. Examination using the held-out data indicated that all models had robust predictive precision and provided significantly better estimations than a linear regression model using single electrode EEG variables. Furthermore, in limited electrode condition, non-linear SVR model showed significantly better precision than linear SVR model. The method proposed in this study helps investigations into MW in various little-examined situations. Further, by measuring MW with a high temporal resolution EEG, unclear aspects of MW, such as time series variation, are expected to be revealed. Furthermore, our suggestion that a few electrodes can also predict MW contributes to the development of neuro-feedback studies.

  2. High-resolution simulations of unstable cylindrical gravity currents undergoing wandering and splitting motions in a rotating system

    Science.gov (United States)

    Dai, Albert; Wu, Ching-Sen

    2018-02-01

    High-resolution simulations of unstable cylindrical gravity currents when wandering and splitting motions occur in a rotating system are reported. In this study, our attention is focused on the situation of unstable rotating cylindrical gravity currents when the ratio of Coriolis to inertia forces is larger, namely, 0.5 ≤ C ≤ 2.0, in comparison to the stable ones when C ≤ 0.3 as investigated previously by the authors. The simulations reproduce the major features of the unstable rotating cylindrical gravity currents observed in the laboratory, i.e., vortex-wandering or vortex-splitting following the contraction-relaxation motion, and good agreement is found when compared with the experimental results on the outrush radius of the advancing front and on the number of bulges. Furthermore, the simulations provide energy budget information which could not be attained in the laboratory. After the heavy fluid is released, the heavy fluid collapses and a contraction-relaxation motion is at work for approximately 2-3 revolutions of the system. During the contraction-relaxation motion of the heavy fluid, the unstable rotating cylindrical gravity currents behave similar to the stable ones. Towards the end of the contraction-relaxation motion, the dissipation rate in the system reaches a local minimum and a quasi-geostrophic equilibrium state is reached. After the quasi-geostrophic equilibrium state, vortex-wandering or vortex-splitting may occur depending on the ratio of Coriolis to inertia forces. The vortex-splitting process begins with non-axisymmetric bulges and, as the bulges grow, the kinetic energy increases at the expense of decreasing potential energy in the system. The completion of vortex-splitting is accompanied by a local maximum of dissipation rate and a local maximum of kinetic energy in the system. A striking feature of the unstable rotating cylindrical gravity currents is the persistent upwelling and downwelling motions, which are observed for both the

  3. A Logarithmic-Amplitude Polar Diagram

    Directory of Open Access Journals (Sweden)

    Trond Andresen

    2001-04-01

    Full Text Available A polar diagram where the amplitude of the transfer function is on a logarithmic scale, is presented. This gives a one-size-fits-all diagram with no need for zooming in and out, and no need for additional reasoning about infinite-radius encirclements when there are poles on the imaginary axis - as opposed to what is usually neccessary with the standard polar (Nyquist- diagram. All properties needed for stability considerations are upheld, such as encirclements, gain and phase margins. The path for s in the loop transfer function is carefully chosen with regard to possible poles on the imaginary axis. Small excursions into the right half plane in the form of arcs of different-sized logarithmic spirals result in corresponding large but finite arcs that do not overlap in the logarithmic polar plots.

  4. Pathways with PathWhiz.

    Science.gov (United States)

    Pon, Allison; Jewison, Timothy; Su, Yilu; Liang, Yongjie; Knox, Craig; Maciejewski, Adam; Wilson, Michael; Wishart, David S

    2015-07-01

    PathWhiz (http://smpdb.ca/pathwhiz) is a web server designed to create colourful, visually pleasing and biologically accurate pathway diagrams that are both machine-readable and interactive. As a web server, PathWhiz is accessible from almost any place and compatible with essentially any operating system. It also houses a public library of pathways and pathway components that can be easily viewed and expanded upon by its users. PathWhiz allows users to readily generate biologically complex pathways by using a specially designed drawing palette to quickly render metabolites (including automated structure generation), proteins (including quaternary structures, covalent modifications and cofactors), nucleic acids, membranes, subcellular structures, cells, tissues and organs. Both small-molecule and protein/gene pathways can be constructed by combining multiple pathway processes such as reactions, interactions, binding events and transport activities. PathWhiz's pathway replication and propagation functions allow for existing pathways to be used to create new pathways or for existing pathways to be automatically propagated across species. PathWhiz pathways can be saved in BioPAX, SBGN-ML and SBML data exchange formats, as well as PNG, PWML, HTML image map or SVG images that can be viewed offline or explored using PathWhiz's interactive viewer. PathWhiz has been used to generate over 700 pathway diagrams for a number of popular databases including HMDB, DrugBank and SMPDB. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  5. Geographical Income Polarization

    DEFF Research Database (Denmark)

    Azhar, Hussain; Jonassen, Anders Bruun

    inter municipal income inequality. Counter factual simulations show that rising property prices to a large part explain the rise in polarization. One side-effect of polarization is tendencies towards a parallel polarization of residence location patterns, where low skilled individuals tend to live......In this paper we estimate the degree, composition and development of geographical income polarization based on data at the individual and municipal level in Denmark from 1984 to 2002. Rising income polarization is reconfirmed when applying new polarization measures, the driving force being greater...

  6. Yeats, Myth and Mythical Method : A Close Reading of the Representations of Celtic and Catholic Mythology in “The Wanderings of Oisin”

    OpenAIRE

    Sperens, Jenny

    2013-01-01

    “The Wanderings of Oisin” was published in 1889 and is one of W.B Yeats’ earliest poems and is the main focus for this essay. The poem depicts the duality of Irish identity and the transition from one system of belief to another. This essay will demonstrate that W.B Yeats uses Celtic and Catholic mythology in “The Wanderings of Oisin” in order to reflect his contemporary Ireland. The essay begins with a deifintion and a discussion about the words 'myth' and 'mythical method'. The second part ...

  7. Errance identitaire, errance scripturale : Patrick Modiano, W. G. Sebald, Fred Wander et la littérature de l'après

    OpenAIRE

    Julien, Aurélie

    2016-01-01

    The French writer Patrick Modiano (1945-), the German writer W.G. Sebald (1944-2001) and the Austrian writer Fred Wander (1917-2006) consider the relationship between errance and literature after 1945: They are moved by the absence of the witnesses and the disparition of the past after World War II. Their books are haunted by memory lapses and identity disorder and they present a lot of trips accross worlds ; the characters of Modiano, Sebald and Wander are in exile or in transit, far away fr...

  8. Path integrals and quantum processes

    CERN Document Server

    Swanson, Marc S

    1992-01-01

    In a clearly written and systematic presentation, Path Integrals and Quantum Processes covers all concepts necessary to understand the path integral approach to calculating transition elements, partition functions, and source functionals. The book, which assumes only a familiarity with quantum mechanics, is ideal for use as a supplemental textbook in quantum mechanics and quantum field theory courses. Graduate and post-graduate students who are unfamiliar with the path integral will also benefit from this contemporary text. Exercise sets are interspersed throughout the text to facilitate self-

  9. Common Path Side Viewing Monolithic Ball Lens Probe for Optical Coherence Tomography

    OpenAIRE

    Kanwarpal, Singh; Daisuke, Yamada; Guillermo, Tearney

    2015-01-01

    Common path probes are highly desirable for optical coherence tomography as they reduce system complexity and cost by eliminating the need of dispersion compensation and polarization controlling optics. In this work, we demonstrate a monolithic ball lens based, common path, side viewing probe that is suitable for Fourier domain optical coherence tomography. The probe design parameters were simulated in Zemax modeling software and the simulated performance parameters were compared with experim...

  10. Innovation paths in wind power

    DEFF Research Database (Denmark)

    Lema, Rasmus; Nordensvärd, Johan; Urban, Frauke

    Denmark and Germany both make substantial investments in low carbon innovation, not least in the wind power sector. These investments in wind energy are driven by the twin objectives of reducing carbon emissions and building up international competitive advantage. Support for wind power dates back...... paths: government policies, demand conditions, geography, value chains, and the strategies undertaken by firms. It demonstrates that the innovation paths common to both countries have roots in a confluence of determining factors which are mainly due to social and political priorities, preferences...... Denmark and Germany have common national causes, while company-specific strategies also influence the innovation paths in significant ways. This raises important questions about the national specificity of innovation paths in wind power development. Finally, the paper briefly addresses the increasing...

  11. An Introduction to Path Analysis

    Science.gov (United States)

    Wolfe, Lee M.

    1977-01-01

    The analytical procedure of path analysis is described in terms of its use in nonexperimental settings in the social sciences. The description assumes a moderate statistical background on the part of the reader. (JKS)

  12. Polarized Light Corridor Demonstrations.

    Science.gov (United States)

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  13. Paths into Professional School: A Research Note

    Science.gov (United States)

    Helfrich, Margaret L.

    1975-01-01

    The literature of occupations and professions implies that there may be different paths into given work activities. Four different paths into dental school are described and illustrated, and different conditions are associated with each path. (Author/BP)

  14. Path-based Queries on Trajectory Data

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Pelekis, Nikos; Theodoridis, Yannis

    2014-01-01

    In traffic research, management, and planning a number of path-based analyses are heavily used, e.g., for computing turn-times, evaluating green waves, or studying traffic flow. These analyses require retrieving the trajectories that follow the full path being analyzed. Existing path queries cannot...... sufficiently support such path-based analyses because they retrieve all trajectories that touch any edge in the path. In this paper, we define and formalize the strict path query. This is a novel query type tailored to support path-based analysis, where trajectories must follow all edges in the path...... a specific path by only retrieving data from the first and last edge in the path. To correctly answer strict path queries existing network-constrained trajectory indexes must retrieve data from all edges in the path. An extensive performance study of NETTRA using a very large real-world trajectory data set...

  15. Development of PATH Gaming Methodology

    Science.gov (United States)

    1988-06-30

    In open games, on the other hand , the teams are allowed to interact directly (either verbally or in writing) without the control team restricting the...real world this loss is not serious. A path game can consist of as few as one team to as many as four. A color coding scheme is used as a short hand ... Strenghts ---------------------------------- 74 6.4 Weaknesses --------------------------------- 76 7 Extended Path Games ----------------------------- 78

  16. Formal language constrained path problems

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, C.; Jacob, R.; Marathe, M.

    1997-07-08

    In many path finding problems arising in practice, certain patterns of edge/vertex labels in the labeled graph being traversed are allowed/preferred, while others are disallowed. Motivated by such applications as intermodal transportation planning, the authors investigate the complexity of finding feasible paths in a labeled network, where the mode choice for each traveler is specified by a formal language. The main contributions of this paper include the following: (1) the authors show that the problem of finding a shortest path between a source and destination for a traveler whose mode choice is specified as a context free language is solvable efficiently in polynomial time, when the mode choice is specified as a regular language they provide algorithms with improved space and time bounds; (2) in contrast, they show that the problem of finding simple paths between a source and a given destination is NP-hard, even when restricted to very simple regular expressions and/or very simple graphs; (3) for the class of treewidth bounded graphs, they show that (i) the problem of finding a regular language constrained simple path between source and a destination is solvable in polynomial time and (ii) the extension to finding context free language constrained simple paths is NP-complete. Several extensions of these results are presented in the context of finding shortest paths with additional constraints. These results significantly extend the results in [MW95]. As a corollary of the results, they obtain a polynomial time algorithm for the BEST k-SIMILAR PATH problem studied in [SJB97]. The previous best algorithm was given by [SJB97] and takes exponential time in the worst case.

  17. Pigment analysis of a color-leaf mutant in Wandering Jew (Tradescantia fluminensis) irradiated by carbon ions

    International Nuclear Information System (INIS)

    He Jinyu; Lu Dong; Yu Lixia; Li Wenjian

    2011-01-01

    Many mutants of plant induced by heavy ion beam irradiation have been reported in recent years, but leaf anthocyan mutants induced by ion irradiation in evergreen were rarely found. In this study, a color-leaf mutant with purple leaves, stems and petals was isolated from clones of Wandering Jew irradiated by 95.8 MeV/u carbon ion beam. The concentration and histological distribution of leaf pigment were surveyed in wild type and mutant. In mutant, contents of total chlorophylls (Chl), chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoids (Car) decreased significantly, while concentration of the anthocyanins was 6.2-fold higher than that of wild type. Further composition analysis of anthocyanins by electrospray ionization mass spectrometry (ESI-MS) indicated that the purple pigmentation of leaves in mutant was caused by accumulation of petunidin anthocyanin. Microscopic examination showed that most petunidin anthocyanin accumulated in the lower epidermis, and little in vascular parenchyma of mutant, while there was no pigment in wild type. Meanwhile, in spongy parenchyma of mutant we observed little Chl, which the wild type abounds in. In conclusion, the color-leaf mutant of Wandering Jew induced by irradiation of carbon ions was improved in ornamental value, and it could be contribute to variation in level, component and distribution of foliar pigment. The possible mutation mechanisms were discussed. (authors)

  18. Influence of age, sex and breeding status on mercury accumulation patterns in the wandering albatross Diomedea exulans.

    Science.gov (United States)

    Tavares, S; Xavier, J C; Phillips, R A; Pereira, M E; Pardal, M A

    2013-10-01

    Although mercury bio-amplifies through the food chain and accumulates in top predators, mercury concentrations in tissues of the wandering albatross are greater than in any other vertebrate, including closely related species. In order to explore the alternative explanations for this pattern, we measured total mercury concentrations in feathers, plasma and blood cells of wandering albatrosses of known age, sex and breeding status sampled at South Georgia. Mercury concentrations were low in feathers and blood components of chicks, and higher in the feathers of young pre-breeders than in feathers or blood of older pre-breeders and breeding adults. There was no effect of sex on mercury concentrations in the feathers of pre-breeders or breeding adults, whereas levels were significantly higher in blood cells of breeding females than males. The high feather mercury concentrations of young pre-breeders compared with older birds suggest an increase in moult frequency as birds approach maturity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Extreme variation in migration strategies between and within wandering albatross populations during their sabbatical year, and their fitness consequences.

    Science.gov (United States)

    Weimerskirch, Henri; Delord, Karine; Guitteaud, Audrey; Phillips, Richard A; Pinet, Patrick

    2015-03-09

    Migratory behavior, routes and zones used during the non-breeding season are assumed to have been selected to maximize fitness, and can lead to genetic differentiation. Yet, here we show that migration strategies differ markedly between and within two genetically similar populations of wandering albatross Diomedea exulans from the Crozet and Kerguelen archipelagos in the Indian Ocean. Wandering albatrosses usually breed biennially if successful, and during the sabbatical year, all birds from Kerguelen migrate to the Pacific Ocean, whereas most from Crozet are sedentary. Instead of taking the shortest routes, which would involve a return against headwinds, migratory birds fly with the westerly winds, requiring detours of 10,000 s km. In total, migrants circumnavigate Antarctica 2 to 3 times, covering more than 120,000 km in a single sabbatical year. Our results indicate strong links between migratory behavior and fitness; all birds from Kerguelen breed biennially, whereas a significant proportion of those from Crozet, especially females, are sedentary and breed in consecutive calendar years. To breed annually, these females temporarily change mate, but return to their original partner in the following year. This extreme variation in migratory behavior has important consequences in term of life history evolution and susceptibility to climate change and fisheries.

  20. Translation from Chinese of Poems 1–9 from 'Wandering Spirit and Metaphysical Thoughts' by Gao Xingjian

    Directory of Open Access Journals (Sweden)

    Mabel Lee

    2017-05-01

    Full Text Available The 2000 Nobel Laureate for Literature, Gao Xingjian, suffered cardiac arrest while directing rehearsals for his mega-scale opera Snow in August that was due to premiere in late 2002 at the National Opera House, Taipei. He recovered, and the opera premiered as scheduled with the help of a co-director before he returned to Paris to direct the Comédie Français premiere of his Quatre quatuors pour un week-end. He underwent surgery in February and March of 2003, but was soon again back at work. The year 2003 had been designated “Gao Xingjian Year” by the City of Marseille, and he would direct his new play Le Quêteur de la Mort at Théâtre du Gymnase, and then his Snow in August at Opéra de Marseille. It was during rehearsals for the former that he collapsed again, and was hospitalized: the play was co-directed by Romain Bonnin, 23–26 September 2003. Large exhibitions of Gao’s artworks had been held earlier that year, but the performance of Snow in August was postponed. During his recuperation for most of 2004, he sometimes wrote poems, some of which he later polished or rewrote for his collection Wandering Spirit and Metaphysical Thoughts (2012. These translations from the Chinese into English of the first 9 poems in Wandering Spirit and Metaphysical Thoughts (2012 are by acclaimed translator Mabel Lee.

  1. Polarized Moessbauer transitions

    International Nuclear Information System (INIS)

    Barb, D.

    1975-01-01

    Theoretical aspects of the emission, absorption and scattering of polarized gamma rays are reviewed for a general case of combined magnetic and electric hyperfine interactions; various possibilities of obtaining polarized gamma sources are described and examples are given of the applications of Moessbauer spectroscopy with polarized gamma rays in solving problems of solid state physics. (A.K.)

  2. Asteroidal Quadruples in non Rooted Path Graphs

    Directory of Open Access Journals (Sweden)

    Gutierrez Marisa

    2015-11-01

    Full Text Available A directed path graph is the intersection graph of a family of directed subpaths of a directed tree. A rooted path graph is the intersection graph of a family of directed subpaths of a rooted tree. Rooted path graphs are directed path graphs. Several characterizations are known for directed path graphs: one by forbidden induced subgraphs and one by forbidden asteroids. It is an open problem to find such characterizations for rooted path graphs. For this purpose, we are studying in this paper directed path graphs that are non rooted path graphs. We prove that such graphs always contain an asteroidal quadruple.

  3. Drifting from Slow to "D'oh!": Working Memory Capacity and Mind Wandering Predict Extreme Reaction Times and Executive Control Errors

    Science.gov (United States)

    McVay, Jennifer C.; Kane, Michael J.

    2012-01-01

    A combined experimental, individual-differences, and thought-sampling study tested the predictions of executive attention (e.g., Engle & Kane, 2004) and coordinative binding (e.g., Oberauer, Suss, Wilhelm, & Sander, 2007) theories of working memory capacity (WMC). We assessed 288 subjects' WMC and their performance and mind-wandering rates…

  4. Drifting from Slow to “D’oh!” Working Memory Capacity and Mind Wandering Predict Extreme Reaction Times and Executive-Control Errors

    Science.gov (United States)

    McVay, Jennifer C.; Kane, Michael J.

    2012-01-01

    A combined experimental, individual-differences, and thought-sampling study tested the predictions of executive attention (e.g., Engle & Kane, 2004) and coordinative binding (e.g., Oberauer, Süß, Wilhelm, & Sander, 2007) theories of working memory capacity (WMC). We assessed 288 subjects’ WMC and their performance and mind-wandering rates during a sustained-attention task; subjects completed either a go/no-go version requiring executive control over habit, or a vigilance version that did not. We further combined the data with those from McVay and Kane (2009) to: (1) gauge the contributions of WMC and attentional lapses to the worst-performance rule and the tail, or τ parameter, of response time (RT) distributions; (2) assess which parameters from a quantitative evidence-accumulation RT model were predicted by WMC and mind-wandering reports, and (3) consider intra-subject RT patterns – particularly, speeding – as potential objective markers of mind wandering. We found that WMC predicted action and thought control in only some conditions, that attentional lapses (indicated by TUT reports and drift-rate variability in evidence accumulation) contributed to τ, performance accuracy, and WMC’s association with them, and that mind-wandering experiences were not predicted by trial-to-trial RT changes, and so they cannot always be inferred from objective performance measures. PMID:22004270

  5. Working Memory Capacity, Mind Wandering, and Creative Cognition: An Individual-Differences Investigation into the Benefits of Controlled Versus Spontaneous Thought

    Science.gov (United States)

    Smeekens, Bridget A.; Kane, Michael J.

    2015-01-01

    Should executive control, as indicated by working memory capacity (WMC) and mind-wandering propensity, help or hinder creativity? Sustained and focused attention should help guide a selective search of solution-relevant information in memory and help inhibit uncreative, yet accessible, ideas. However, unfocused attention and daydreaming should allow mental access to more loosely relevant concepts, remotely linked to commonplace solutions. Three individual-differences studies inserted incubation periods into one or two divergent thinking tasks and tested whether WMC (assessed by complex span tasks) and incubation-period mind wandering (assessed as probed reports of task-unrelated thought [TUT]) predicted post-incubation performance. Retrospective self-reports of Openness (Experiment 2) and mind-wandering and daydreaming propensity (Experiment 3) complemented our thought-probe assessments of TUT. WMC did not correlate with creativity in divergent thinking, whereas only the questionnaire measure of daydreaming, but not probed thought reports, weakly predicted creativity; the fact that in-the-moment TUTs did not correlate divergent creativity is especially problematic for claims that mind-wandering processes contribute to creative cognition. Moreover, the fact that WMC tends to strongly predict analytical problem solving and reasoning, but may not correlate with divergent thinking, provides a useful boundary condition for defining WMC’s nomological net. On balance, our data provide no support for either benefits or costs of executive control for at least one component of creativity. PMID:28458764

  6. The Physics of Polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    2015-10-01

    The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

  7. Shortest Paths in Multiplex Networks.

    Science.gov (United States)

    Ghariblou, Saeed; Salehi, Mostafa; Magnani, Matteo; Jalili, Mahdi

    2017-05-12

    The shortest path problem is one of the most fundamental networks optimization problems. Nowadays, individuals interact in extraordinarily numerous ways through their offline and online life (e.g., co-authorship, co-workership, or retweet relation in Twitter). These interactions have two key features. First, they have a heterogeneous nature, and second, they have different strengths that are weighted based on their degree of intimacy, trustworthiness, service exchange or influence among individuals. These networks are known as multiplex networks. To our knowledge, none of the previous shortest path definitions on social interactions have properly reflected these features. In this work, we introduce a new distance measure in multiplex networks based on the concept of Pareto efficiency taking both heterogeneity and weighted nature of relations into account. We then model the problem of finding the whole set of paths as a form of multiple objective decision making and propose an exact algorithm for that. The method is evaluated on five real-world datasets to test the impact of considering weights and multiplexity in the resulting shortest paths. As an application to find the most influential nodes, we redefine the concept of betweenness centrality based on the proposed shortest paths and evaluate it on a real-world dataset from two-layer trade relation among countries between years 2000 and 2015.

  8. Path Integrals in Quantum Mechanics

    International Nuclear Information System (INIS)

    Louko, J

    2005-01-01

    Jean Zinn-Justin's textbook Path Integrals in Quantum Mechanics aims to familiarize the reader with the path integral as a calculational tool in quantum mechanics and field theory. The emphasis is on quantum statistical mechanics, starting with the partition function Tr exp(-β H) and proceeding through the diffusion equation to barrier penetration problems and their semiclassical limit. The 'real time' path integral is defined via analytic continuation and used for the path-integral representation of the nonrelativistic S-matrix and its perturbative expansion. Holomorphic and Grassmannian path integrals are introduced and applied to nonrelativistic quantum field theory. There is also a brief discussion of path integrals in phase space. The introduction includes a brief historical review of path integrals, supported by a bibliography with some 40 entries. As emphasized in the introduction, mathematical rigour is not a central issue in the book. This allows the text to present the calculational techniques in a very readable manner: much of the text consists of worked-out examples, such as the quartic anharmonic oscillator in the barrier penetration chapter. At the end of each chapter there are exercises, some of which are of elementary coursework type, but the majority are more in the style of extended examples. Most of the exercises indeed include the solution or a sketch thereof. The book assumes minimal previous knowledge of quantum mechanics, and some basic quantum mechanical notation is collected in an appendix. The material has a large overlap with selected chapters in the author's thousand-page textbook Quantum Field Theory and Critical Phenomena (2002 Oxford: Clarendon). The stand-alone scope of the present work has, however, allowed a more focussed organization of this material, especially in the chapters on, respectively, holomorphic and Grassmannian path integrals. In my view the book accomplishes its aim admirably and is eminently usable as a textbook

  9. The polar year starts in March. Arctics promises. When the North path will be opened to maritime traffic; L'annee polaire commence en mars. Les promesses de l'Arctique. Quand la voie nord s'ouvrira au trafic maritime

    Energy Technology Data Exchange (ETDEWEB)

    Lepetit, V.; Remoue, A

    2007-02-15

    From Greenland to Alaska and from the Barents sea to the Okhotsk sea, oil companies are performing exploratory drillings looking for the North pole black gold. Far away from being an utopia, this new conquest of the great north is organizing yet. The Arctic hydrocarbon reserves may represent 10% of the world reserves. Moreover, with the increasing melting of ice sheets, the Arctic path will be opened to navigation and exploration in less than 25 years. The great north territories are shared between eight countries (USA, Canada, Denmark, Island, Norway, Sweden, Finland and Russia) and leads to disputes about the limits of territorial waters. (J.S.)

  10. [Review] Polarization and Polarimetry

    Science.gov (United States)

    Trippe, Sascha

    2014-02-01

    Polarization is a basic property of light and is fundamentally linked to the internal geometry of a source of radiation. Polarimetry complements photometric, spectroscopic, and imaging analyses of sources of radiation and has made possible multiple astrophysical discoveries. In this article I review (i) the physical basics of polarization: electromagnetic waves, photons, and parameterizations; (ii) astrophysical sources of polarization: scattering, synchrotron radiation, active media, and the Zeeman, Goldreich-Kylafis, and Hanle effects, as well as interactions between polarization and matter (like birefringence, Faraday rotation, or the Chandrasekhar-Fermi effect); (iii) observational methodology: on-sky geometry, influence of atmosphere and instrumental polarization, polarization statistics, and observational techniques for radio, optical, and X/γ wavelengths; and (iv) science cases for astronomical polarimetry: solar and stellar physics, planetary system bodies, interstellar matter, astrobiology, astronomical masers, pulsars, galactic magnetic fields, gamma-ray bursts, active galactic nuclei, and cosmic microwave background radiation.

  11. Polarization in Sagittarius A*

    OpenAIRE

    Bower, Geoffrey C.

    2000-01-01

    We summarize the current state of polarization observations of Sagittarius A*, the compact radio source and supermassive black hole candidate in the Galactic Center. These observations are providing new tools for understanding accretion disks, jets and their environments. Linear polarization observations have shown that Sgr A* is unpolarized at frequencies as high as 86 GHz. However, recent single-dish observations indicate that Sgr A* may have strong linear polarization at frequencies higher...

  12. Investigation on the influence of intensity scintillation and beam wander in space optical uplink DWDM communication system

    Science.gov (United States)

    Li, Mi; Chen, Mengji; Zhang, Xuping; Cong, Hengji; Song, Yuejiang; Lu, Yuangang

    2016-04-01

    Dense wavelength division multiplexing (DWDM) has been widely applied in ground optical communication. However, the technology of DWDM is still not mature enough in the space optical communication system. In order to further advance the use of DWDM into space optical communication, the probability density function (PDF) and the bit-error rate (BER) performance of DWDM is investigated in uplink communications under the influence of atmospheric turbulence, consisting of intensity scintillation and beam wander caused by atmospheric turbulence. Numerical results show that the atmospheric turbulence has a great impact on BER and PDF, and wavelength, divergence angel, and other relevant parameters should be carefully considered in this DWDM system. This work can be conducive for improving DWDM design of space optical uplink communication systems.

  13. Age-related variation in reproductive traits in the wandering albatross: evidence for terminal improvement following senescence.

    Science.gov (United States)

    Froy, Hannah; Phillips, Richard A; Wood, Andrew G; Nussey, Daniel H; Lewis, Sue

    2013-05-01

    The processes driving age-related variation in demographic rates are central to understanding population and evolutionary ecology. An increasing number of studies in wild vertebrates find evidence for improvements in reproductive performance traits in early adulthood, followed by senescent declines in later life. However, life history theory predicts that reproductive investment should increase with age as future survival prospects diminish, and that raised reproductive investment may have associated survival costs. These non-mutually exclusive processes both predict an increase in breeding performance at the terminal breeding attempt. Here, we use a 30-year study of wandering albatrosses (Diomedea exulans) to disentangle the processes underpinning age-related variation in reproduction. Whilst highlighting the importance of breeding experience, we reveal senescent declines in performance are followed by a striking increase in breeding success and a key parental investment trait at the final breeding attempt. © 2013 Blackwell Publishing Ltd/CNRS.

  14. Wandering Fish Bone: a Case of Pelvic Abscess due to Rectum Perforation Resulting from an Accidental Fish Bone Ingestion

    Directory of Open Access Journals (Sweden)

    Sirous Abbasi

    2010-09-01

    Full Text Available Fish bone is the most common foreign body that is ingested accidentally and can be caused gastrointestinal complications such as perforation, abstraction, and abscess. We describe a 75-year-old man who suffered from constipation, diarrhea, and fever and chills for 3 months. He had mild tenderness in hypogasteric region and also mild tenderness and swelling on anterior rectal wall and prostate upon clinical examination. The abdominal and pelvic sonography and CT scan findings suggested existence of abscess in the space of between bladder and rectum. The patient underwent laparotomy to drainage the pelvic abscess. The surgeon found a 6-cm fish bone which was embedded in the abscess. The presented case indicated the importance of accidental fish bone ingestion and its possible complications. In addition, the patients with abdominal pain, GI bleeding, and fever of unknown origin living in the seaside regions, the wandering fish bone as a differential diagnosis should be kept in mind.

  15. Airborne Laser Polarization Sensor

    Science.gov (United States)

    Kalshoven, James, Jr.; Dabney, Philip

    1991-01-01

    Instrument measures polarization characteristics of Earth at three wavelengths. Airborne Laser Polarization Sensor (ALPS) measures optical polarization characteristics of land surface. Designed to be flown at altitudes of approximately 300 m to minimize any polarizing or depolarizing effects of intervening atmosphere and to look along nadir to minimize any effects depending on look angle. Data from measurements used in conjunction with data from ground surveys and aircraft-mounted video recorders to refine mathematical models used in interpretation of higher-altitude polarimetric measurements of reflected sunlight.

  16. Polarization at SLC

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1988-07-01

    The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs

  17. Rainbow paths with prescribed ends

    DEFF Research Database (Denmark)

    Alishahi, Meysam; Taherkhani, Ali; Thomassen, Carsten

    2011-01-01

    It was conjectured in [S. Akbari, F. Khaghanpoor, and S. Moazzeni. Colorful paths in vertex coloring of graphs. Preprint] that, if G is a connected graph distinct from C-7, then there is a chi(G)-coloring of G in which every vertex v is an element of V(G) is an initial vertex of a path P with chi......(G) vertices whose colors are different. In[S. Akbari, V. Liaghat, and A. Nikzad. Colorful paths in vertex coloring of graphs. Electron. J. Combin. 18(1):P17, 9pp, 2011] this was proved with left perpendicular chi(G)/2right perpendicular vertices instead of chi(G) vertices. We strengthen this to chi(G) - 1...... finite, and has finite chromatic number, then the k-coloring exists for every k >= chi(G). In fact, the k-coloring can be chosen such that every vertex is a starting vertex of an infinite path such that the color increases by 1 (mod k) along each edge. The method is based on the circular chromatic number...

  18. Wandering off the centre: a characterization of the random motion of intermediate-mass black holes in star clusters

    Science.gov (United States)

    de Vita, Ruggero; Trenti, Michele; MacLeod, Morgan

    2018-04-01

    Despite recent observational efforts, unequivocal signs for the presence of intermediate-mass black holes (IMBHs) in globular clusters (GCs) have not been found yet. Especially when the presence of IMBHs is constrained through dynamical modelling of stellar kinematics, it is fundamental to account for the displacement that the IMBH might have with respect to the GC centre. In this paper, we analyse the IMBH wandering around the stellar density centre using a set of realistic direct N-body simulations of star cluster evolution. Guided by the simulation results, we develop a basic yet accurate model that can be used to estimate the average IMBH radial displacement (〈rbh〉) in terms of structural quantities as the core radius (rc), mass (Mc), and velocity dispersion (σc), in addition to the average stellar mass (mc) and the IMBH mass (Mbh). The model can be expressed by the equation /r_c=A(m_c/M_bh)^α [σ _c^2r_c/(GM_c)]^β, in which the free parameters A, α, and β are calculated through comparison with the numerical results on the IMBH displacement. The model is then applied to Galactic GCs, finding that for an IMBH mass equal to 0.1 per cent of the GC mass, the typical expected displacement of a putative IMBH is around 1 arcsec for most Galactic GCs, but IMBHs can wander to larger angular distances in some objects, including a prediction of a 2.5 arcsec displacement for NGC 5139 (ω Cen), and >10 arcsec for NGC5053, NGC6366, and ARP2.

  19. Polar-Direct-Drive Experiments on OMEGA

    International Nuclear Information System (INIS)

    Marshall, F.J.; Craxton, R.S.; Bonino, M.J.; Epstein, R.; Glebov, V.Yu.; Jacobs-Perkins, D.; Knauer, J.P.; Marozas, J.A.; McKenty, P.W.; Noyes, S.G.; Radha, P.B.; Seka, W.; Skupsky, S.; Smalyuk

    2006-01-01

    Polar direct drive (PDD), a promising ignition path for the NIF while the beams are in the indirect-drive configuration, is currently being investigated on the OMEGA laser system by using 40 beams in six rings repointed to more uniformly illuminate the target. The OMEGA experiments are being performed with standard, ''warm'' targets with and without the use of an equatorial ''Saturn-like'' toroidally shaped CH ring. Target implosion symmetry is diagnosed with framed x-ray backlighting using additional OMEGA beams and by time-integrated x-ray imaging of the stagnating core

  20. Enzymatic reaction paths as determined by transition path sampling

    Science.gov (United States)

    Masterson, Jean Emily

    Enzymes are biological catalysts capable of enhancing the rates of chemical reactions by many orders of magnitude as compared to solution chemistry. Since the catalytic power of enzymes routinely exceeds that of the best artificial catalysts available, there is much interest in understanding the complete nature of chemical barrier crossing in enzymatic reactions. Two specific questions pertaining to the source of enzymatic rate enhancements are investigated in this work. The first is the issue of how fast protein motions of an enzyme contribute to chemical barrier crossing. Our group has previously identified sub-picosecond protein motions, termed promoting vibrations (PVs), that dynamically modulate chemical transformation in several enzymes. In the case of human heart lactate dehydrogenase (hhLDH), prior studies have shown that a specific axis of residues undergoes a compressional fluctuation towards the active site, decreasing a hydride and a proton donor--acceptor distance on a sub-picosecond timescale to promote particle transfer. To more thoroughly understand the contribution of this dynamic motion to the enzymatic reaction coordinate of hhLDH, we conducted transition path sampling (TPS) using four versions of the enzymatic system: a wild type enzyme with natural isotopic abundance; a heavy enzyme where all the carbons, nitrogens, and non-exchangeable hydrogens were replaced with heavy isotopes; and two versions of the enzyme with mutations in the axis of PV residues. We generated four separate ensembles of reaction paths and analyzed each in terms of the reaction mechanism, time of barrier crossing, dynamics of the PV, and residues involved in the enzymatic reaction coordinate. We found that heavy isotopic substitution of hhLDH altered the sub-picosecond dynamics of the PV, changed the favored reaction mechanism, dramatically increased the time of barrier crossing, but did not have an effect on the specific residues involved in the PV. In the mutant systems

  1. Institutional care paths: Development, implementation, and evaluation.

    Science.gov (United States)

    Leonard, Mandy C; Bauer, Seth R; Ahrens, Christine; Reddy, Anita; Katzan, Irene

    2017-09-15

    The Cleveland Clinic experience with care paths, including their creation and implementation, challenges overcome during development and testing, and outcomes of selected care path evaluations, is described. Care paths are tools to assist healthcare professionals in practicing evidence-based medicine. The Cleveland Clinic health system has implemented or is developing approximately 100 care paths, including care paths designed to optimize management of sepsis and septic shock and to promote timely use of i.v. tissue plasminogen activator and correct dosing of antithrombotics and statins in patients with stroke. Key steps in successful care path initiatives include (1) identifying key stakeholders, (2) achieving stakeholder consensus on a standardized approach to disease or condition management, (3) cultivating provider awareness of care paths, (4) incorporating care path tools into the electronic health record and workflow processes, and (5) securing the resources to develop, implement, and maintain care paths. Electronic health records facilitate the use of and adherence to care paths. After care path implementation, revisions are typically needed due to unexpected issues not initially identified and to optimize care path features and support resources for clinical practice. Ongoing evaluation is required to determine whether an implemented care path is producing the intended patient and quality performance outcomes. Care paths provide a standardized approach to treatment or prevention of a disease or condition, reducing unnecessary variability and expense while promoting optimal, cost-effective patient care. Copyright © 2017 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  2. RHIC Polarized proton operation

    International Nuclear Information System (INIS)

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D'Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R.; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.E.; Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-01-01

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP 4 . A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  3. RHIC Polarized proton operation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D' Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R,; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; J.; Severino, F.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J. Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-03-28

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP{sup 4}. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  4. Direct Entry Minimal Path UAV Loitering Path Planning

    Directory of Open Access Journals (Sweden)

    Jay P. Wilhelm

    2017-04-01

    Full Text Available Fixed Wing Unmanned Aerial Vehicles (UAVs performing Intelligence, Surveillance and Reconnaissance (ISR typically fly over Areas of Interest (AOIs to collect sensor data of the ground from the air. If needed, the traditional method of extending sensor collection time is to loiter or turn circularly around the center of an AOI. Current Autopilot systems on small UAVs can be limited in their feature set and typically follow a waypoint chain system that allows for loitering, but requires that the center of the AOI to be traversed which may produce unwanted turns outside of the AOI before entering the loiter. An investigation was performed to compare the current loitering techniques against two novel smart loitering methods. The first method investigated, Tangential Loitering Path Planner (TLPP, utilized paths tangential to the AOIs to enter and exit efficiently, eliminating unnecessary turns outside of the AOI. The second method, Least Distance Loitering Path Planner (LDLPP, utilized four unique flight maneuvers that reduce transit distances while eliminating unnecessary turns outside of the AOI present in the TLPP method. Simulation results concluded that the Smart Loitering Methods provide better AOI coverage during six mission scenarios. It was also determined that the LDLPP method spends less time in transit between AOIs. The reduction in required transit time could be used for surveying additional AOIs.

  5. Our Polar Past

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2009-01-01

    The study of polar exploration is fascinating and offers students insights into the history, culture, and politics that affect the developing sciences at the farthest ends of Earth. Therefore, the authors think there is value in incorporating polar exploration accounts within modern science classrooms, and so they conducted research to test their…

  6. Terahertz polarization imaging

    NARCIS (Netherlands)

    Van der Valk, N.C.J.; Van der Marel, W.A.M.; Planken, P.C.M.

    2005-01-01

    We present a new method to measure the polarization state of a terahertz pulse by using a modified electrooptic sampling setup. To illustrate the power of this method, we show two examples in which the knowledge of the polarization of the terahertz pulse is essential for interpreting the results:

  7. Polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    The acceleration of polarized proton beams in circular accelerators is complicated by the presence of numerous depolarizing spin resonances. Careful and tedious minimization of polarization loss at each of these resonances allowed acceleration of polarized proton beams up to 22 GeV. It has been the hope that Siberian Snakes, which are local spin rotators inserted into ring accelerators, would eliminate these resonances and allow acceleration of polarized beams with the same ease and efficiency that is now routine for unpolarized beams. First tests at IUCF with a full Siberian Snake showed that the spin dynamics with a Snake can be understood in detail. The author now has results of the first tests of a partial Siberian Snake at the AGS, accelerating polarized protons to an energy of about 25 GeV. These successful tests of storage and acceleration of polarized proton beams open up new possibilities such as stored polarized beams for internal target experiments and high energy polarized proton colliders

  8. Polar Science Is Cool!

    Science.gov (United States)

    Weeks, Sophie

    2012-01-01

    Children are fascinated by the fact that polar scientists do research in extremely cold and dangerous places. In the Arctic they might be viewed as lunch by a polar bear. In the Antarctic, they could lose toes and fingers to frostbite and the wind is so fast it can rip skin off. They camp on ice in continuous daylight, weeks from any form of…

  9. Religious and Pilgrimage Tourism: A Path to Sufism

    OpenAIRE

    Elhadary, Tariq

    2017-01-01

    The paper attempts to shed some light on religious tourism as a broad term which lends itself to cover Muslim tourism, Christian tourism, or any other religion linked with the term ‘tourism’. The paper likens religious tourism to Sufi travel and wander. It inquires about the similarities between Sufi wander and religious tourism, and what they both have in common. Moreover, how far and true religious tourism embodies the essence of Sufism in its search for love, peace, and knowledge. Sufism e...

  10. Precision Polarization of Neutrons

    Science.gov (United States)

    Martin, Elise; Barron-Palos, Libertad; Couture, Aaron; Crawford, Christopher; Chupp, Tim; Danagoulian, Areg; Estes, Mary; Hona, Binita; Jones, Gordon; Klein, Andi; Penttila, Seppo; Sharma, Monisha; Wilburn, Scott

    2009-05-01

    Determining polarization of a cold neutron beam to high precision is required for the next generation neutron decay correlation experiments at the SNS, such as the proposed abBA and PANDA experiments. Precision polarimetry measurements were conducted at Los Alamos National Laboratory with the goal of determining the beam polarization to the level of 10-3 or better. The cold neutrons from FP12 were polarized using optically polarized ^3He gas as a spin filter, which has a highly spin-dependent absorption cross section. A second ^ 3He spin filter was used to analyze the neutron polarization after passing through a resonant RF spin rotator. A discussion of the experiment and results will be given.

  11. Optically polarized 3He

    Science.gov (United States)

    Gentile, T. R.; Nacher, P. J.; Saam, B.; Walker, T. G.

    2018-01-01

    This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements. PMID:29503479

  12. Optically polarized 3He

    Science.gov (United States)

    Gentile, T. R.; Nacher, P. J.; Saam, B.; Walker, T. G.

    2017-10-01

    This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements.

  13. Parallel Polarization State Generation.

    Science.gov (United States)

    She, Alan; Capasso, Federico

    2016-05-17

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

  14. Common path endoscopic probes for optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Singh, Kanwarpal; Gardecki, Joseph A.; Tearney, Guillermo J.

    2017-02-01

    Background: Dispersion imbalance and polarization mismatch between the reference and sample arm signals can lead to image quality degradation in optical coherence tomography (OCT). One approach to reduce these image artifacts is to employ a common-path geometry in fiber-based probes. In this work, we report an 800 um diameter all-fiber common-path monolithic probe for coronary artery imaging where the reference signal is generated using an inline fiber partial reflector. Methods: Our common-path probe was designed for swept-source based Fourier domain OCT at 1310 nm wavelength. A face of a coreless fiber was coated with gold and spliced to a standard SMF-28 single mode fiber creating an inline partial reflector, which acted as a reference surface. The other face of the coreless fiber was shaped into a ball lens for focusing. The optical elements were assembled within a 560 µm diameter drive shaft, which was attached to a rotary junction. The drive shaft was placed inside a transparent sheath having an outer diameter of 800 µm. Results: With a source input power of 30mW, the inline common-path probe achieved a sensitivity of 104 dB. Images of human finger skin showed the characteristic layers of skin as well as features such as sweat ducts. Images of coronary arteries ex vivo obtained with this probe enabled visualization of the characteristic architectural morphology of the normal artery wall and known features of atherosclerotic plaque. Conclusion: In this work, we have demonstrated a common path OCT probe for cardiovascular imaging. The probe is easy to fabricate, will reduce system complexity and overall cost. We believe that this design will be helpful in endoscopic applications that require high resolution and a compact form factor.

  15. Path modeling and process control

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar; Rodionova, O.; Pomerantsev, A.

    2007-01-01

    and having three or more stages. The methods are applied to a process control of a multi-stage production process having 25 variables and one output variable. When moving along the process, variables change their roles. It is shown how the methods of path modeling can be applied to estimate variables......Many production processes are carried out in stages. At the end of each stage, the production engineer can analyze the intermediate results and correct process parameters (variables) of the next stage. Both analysis of the process and correction to process parameters at next stage should...... be performed regarding the foreseeable output property y, and with respect to an admissible range of correcting actions for the parameters of the next stage. In this paper the basic principles of path modeling is presented. The mathematics is presented for processes having only one stage, having two stages...

  16. Smooth paths of conditional expectations

    OpenAIRE

    Andruchow, Esteban; Larotonda, Gabriel

    2010-01-01

    Let A be a von Neumann algebra with a finite trace $\\tau$, represented in $H=L^2(A,\\tau)$, and let $B_t\\subset A$ be sub-algebras, for $t$ in an interval $I$. Let $E_t:A\\to B_t$ be the unique $\\tau$-preserving conditional expectation. We say that the path $t\\mapsto E_t$ is smooth if for every $a\\in A$ and $v \\in H$, the map $$ I\

  17. Career path for operations personnel

    International Nuclear Information System (INIS)

    Asher, J.A.

    1985-01-01

    This paper explains how selected personnel can now obtain a Bachelor of Science degree in Physics with a Nuclear Power Operations option. The program went into effect the Fall of 1984. Another program was worked out in 1982 whereby students attending the Nuclear Operators Training Program could obtain an Associates of Science degree in Mechanical Engineering Technology at the end of two years of study. This paper presents tables and charts which describe these programs and outline the career path for operators

  18. Path selection during wormhole growth

    OpenAIRE

    Yang, Y.; Hakim, S. S.; Bruns, S.; Uesugi, K.; Dalby, K. N.; Stipp, S. L. S.; Sørensen, H. O.

    2017-01-01

    Growth of wormholes in porous media can lead to self-organization of flow networks with an overwhelming geometric complexity. Despite decades of study, the mechanism by which a dominant wormhole develops its path during growth remains elusive. Here we show that the trajectory of a growing wormhole can be predicted by identifying the flowpath with a so-called minimum cumulative surface. Our theoretical analysis indicates that the cumulative surface determines the position of the dissolution fr...

  19. The path of code linting

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Join the path of code linting and discover how it can help you reach higher levels of programming enlightenment. Today we will cover how to embrace code linters to offload cognitive strain on preserving style standards in your code base as well as avoiding error-prone constructs. Additionally, I will show you the journey ahead for integrating several code linters in the programming tools your already use with very little effort.

  20. Path integrals in curvilinear coordinates

    International Nuclear Information System (INIS)

    Prokhorov, L.V.

    1984-01-01

    Integration limits are studied for presenting the path integral curvilinear coordinates. For spherical (and topoloqically equivalent) coordinates it is shown that in formulas involving classical action in the exponent integration over all variables should be carried out within infinite limits. Another peculiarity is associated with appearance of the operator q which provides a complete definition of the wave functions out of the physical region. arguments are given upporting the validity of the cited statament in the general case

  1. Path Integrals in Quantum Mechanics

    International Nuclear Information System (INIS)

    Chetouani, L

    2005-01-01

    By treating path integrals the author, in this book, places at the disposal of the reader a modern tool for the comprehension of standard quantum mechanics. Thus the most important applications, such as the tunnel effect, the diffusion matrix, etc, are presented from an original point of view on the action S of classical mechanics while having it play a central role in quantum mechanics. What also emerges is that the path integral describes these applications more richly than are described traditionally by differential equations, and consequently explains them more fully. The book is certainly of high quality in all aspects: original in presentation, rigorous in the demonstrations, judicious in the choice of exercises and, finally, modern, for example in the treatment of the tunnel effect by the method of instantons. Moreover, the correspondence that exists between classical and quantum mechanics is well underlined. I thus highly recommend this book (the French version being already available) to those who wish to familiarize themselves with formulation by path integrals. They will find, in addition, interesting topics suitable for exploring further. (book review)

  2. Nonperturbative path integral expansion II

    International Nuclear Information System (INIS)

    Kaiser, H.J.

    1976-05-01

    The Feynman path integral representation of the 2-point function for a self-interacting Bose field is investigated using an expansion ('Path Integral Expansion', PIE) of the exponential of the kinetic term of the Lagrangian. This leads to a series - illustrated by a graph scheme - involving successively a coupling of more and more points of the lattice space commonly employed in the evaluation of path integrals. The values of the individual PIE graphs depend of course on the lattice constant. Two methods - Pade approximation and Borel-type extrapolation - are proposed to extract information about the continuum limit from a finite-order PIE. A more flexible PIE is possible by expanding besides the kinetic term a suitably chosen part of the interaction term too. In particular, if the co-expanded part is a mass term the calculation becomes only slightly more complicated than in the original formulation and the appearance of the graph scheme is unchanged. A significant reduction of the number of graphs and an improvement of the convergence of the PIE can be achieved by performing certain sums over an infinity of graph elements. (author)

  3. Accelerating cleanup: Paths to closure

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, C.

    1998-06-30

    This document was previously referred to as the Draft 2006 Plan. As part of the DOE`s national strategy, the Richland Operations Office`s Paths to Closure summarizes an integrated path forward for environmental cleanup at the Hanford Site. The Hanford Site underwent a concerted effort between 1994 and 1996 to accelerate the cleanup of the Site. These efforts are reflected in the current Site Baseline. This document describes the current Site Baseline and suggests strategies for further improvements in scope, schedule and cost. The Environmental Management program decided to change the name of the draft strategy and the document describing it in response to a series of stakeholder concerns, including the practicality of achieving widespread cleanup by 2006. Also, EM was concerned that calling the document a plan could be misconstrued to be a proposal by DOE or a decision-making document. The change in name, however, does not diminish the 2006 vision. To that end, Paths to Closure retains a focus on 2006, which serves as a point in time around which objectives and goals are established.

  4. Vector Monte Carlo simulations on atmospheric scattering of polarization qubits.

    Science.gov (United States)

    Li, Ming; Lu, Pengfei; Yu, Zhongyuan; Yan, Lei; Chen, Zhihui; Yang, Chuanghua; Luo, Xiao

    2013-03-01

    In this paper, a vector Monte Carlo (MC) method is proposed to study the influence of atmospheric scattering on polarization qubits for satellite-based quantum communication. The vector MC method utilizes a transmittance method to solve the photon free path for an inhomogeneous atmosphere and random number sampling to determine whether the type of scattering is aerosol scattering or molecule scattering. Simulations are performed for downlink and uplink. The degrees and the rotations of polarization are qualitatively and quantitatively obtained, which agree well with the measured results in the previous experiments. The results show that polarization qubits are well preserved in the downlink and uplink, while the number of received single photons is less than half of the total transmitted single photons for both links. Moreover, our vector MC method can be applied for the scattering of polarized light in other inhomogeneous random media.

  5. Formation and disruption of current paths of anodic porous alumina films by conducting atomic force microscopy

    International Nuclear Information System (INIS)

    Oyoshi, K.; Nigo, S.; Inoue, J.; Sakai, O.; Kitazawa, H.; Kido, G.

    2010-01-01

    Anodic porous alumina (APA) films have a honeycomb cell structure of pores and a voltage-induced bi-stable switching effect. We have applied conducting atomic force microscopy (CAFM) as a method to form and to disrupt current paths in the APA films. A bi-polar switching operation was confirmed. We have firstly observed terminals of current paths as spots or areas typically on the center of the triangle formed by three pores. In addition, though a part of the current path showed repetitive switching, most of them were not observed again at the same position after one cycle of switching operations in the present experiments. This suggests that a part of alumina structure and/or composition along the current paths is modified during the switching operations.

  6. Robust techniques for polarization and detection of nuclear spin ensembles

    Science.gov (United States)

    Scheuer, Jochen; Schwartz, Ilai; Müller, Samuel; Chen, Qiong; Dhand, Ish; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor

    2017-11-01

    Highly sensitive nuclear spin detection is crucial in many scientific areas including nuclear magnetic resonance spectroscopy, magnetic resonance imaging (MRI), and quantum computing. The tiny thermal nuclear spin polarization represents a major obstacle towards this goal which may be overcome by dynamic nuclear spin polarization (DNP) methods. The latter often rely on the transfer of the thermally polarized electron spins to nearby nuclear spins, which is limited by the Boltzmann distribution of the former. Here we utilize microwave dressed states to transfer the high (>92 % ) nonequilibrium electron spin polarization of a single nitrogen-vacancy center (NV) induced by short laser pulses to the surrounding 13C carbon nuclear spins. The NV is repeatedly repolarized optically, thus providing an effectively infinite polarization reservoir. A saturation of the polarization of the nearby nuclear spins is achieved, which is confirmed by the decay of the polarization transfer signal and shows an excellent agreement with theoretical simulations. Hereby we introduce the polarization readout by polarization inversion method as a quantitative magnetization measure of the nuclear spin bath, which allows us to observe by ensemble averaging macroscopically hidden polarization dynamics like Landau-Zener-Stückelberg oscillations. Moreover, we show that using the integrated solid effect both for single- and double-quantum transitions nuclear spin polarization can be achieved even when the static magnetic field is not aligned along the NV's crystal axis. This opens a path for the application of our DNP technique to spins in and outside of nanodiamonds, enabling their application as MRI tracers. Furthermore, the methods reported here can be applied to other solid state systems where a central electron spin is coupled to a nuclear spin bath, e.g., phosphor donors in silicon and color centers in silicon carbide.

  7. A systematic review of accidental injury from fire, wandering and medication self-administration errors for older adults with and without dementia.

    Science.gov (United States)

    Douglas, Alison; Letts, Lori; Richardson, Julie

    2011-01-01

    The assessment of risk of injury in the home is important for older adults when considering whether they are able to live independently. The purpose of this systematic review is to determine the frequency of injury for persons with dementia and the general older adult population, from three sources: fires/burns, medication self-administration errors and wandering. Relevant articles (n=74) were screened and 16 studies were retained for independent review. The studies, although subject to selection and information bias, showed low proportions of morbidity and mortality from the three sources of injury. Data did not allow direct comparison of morbidity and mortality for persons with dementia and the general older adult population; however, data trends suggested greater event frequencies with medication self-administration and wandering for persons with dementia. Assessment targeting these sources of injury should have less emphasis in the general older adult population compared to persons with dementia. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  8. Path-entangled photon sources on nonlinear chips

    Directory of Open Access Journals (Sweden)

    Alexander S. Solntsev

    2017-11-01

    Full Text Available Photon entanglement has a range of applications from secure communication to the tests of quantum mechanics. Utilizing optical nonlinearity for the generation of entangled photons remains the most widely used approach due to its quality and simplicity. The on-chip integration of entangled light sources has enabled the increase of complexity and enhancement of stability compared to bulk optical implementations. Entanglement over different optical paths is uniquely suited for photonic chips, since waveguides are typically optimized for particular wavelength and polarization, making polarization- and frequency-entanglement less practical. In this review we focus on the latest developments in the field of on-chip nonlinear path-entangled photon sources. We provide a review of recent implementations and compare various approaches to tunability, including thermo-optical, electro-optical and all-optical tuning. We also discuss a range of important technical issues, in particular the on-chip separation of the pump and generated entangled photons. Finally, we review different quality control methods, including on-chip quantum tomography and recently discovered classical-quantum analogy that allows to characterize entangled photon sources by performing simple nonlinear measurements in the classical regime.

  9. Polarization at the SLC

    Energy Technology Data Exchange (ETDEWEB)

    Moffeit, K.C.

    1988-10-01

    The Stanford Linear collider was designed to accommodate polarized electron beams. Longitudinally polarized electrons colliding with unpolarized positrons at a center of mass energy near the Z/sup 0/ mass can be used as novel and sensitive probes of the electroweak process. A gallium arsenide based photon emission source will provide a beam of longitudinally polarized electrons of about 45 percent polarization. A system of bend magnets and a superconducting solenoid will be used to rotate the spins so that the polarization is preserved while the 1.21 GeV electrons are stored in the damping ring. Another set of bend magnets and two superconducting solenoids orient the spin vectors so that longitudinal polarization of the electrons is achieved at the collision point with the unpolarized positrons. A system to monitor the polarization based on Moller and Compton scattering will be used. Nearly all major components have been fabricated and tested. Subsystems of the source and polarimeters have been installed, and studies are in progress. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. 8 refs., 16 figs., 1 tab.

  10. Elastic path controller for assistive devices.

    Science.gov (United States)

    Long, B; Rebsamen, B; Burdet, E; Yu, H; Teo, C L

    2005-01-01

    Robotic assistive devices that constrain motion along pre-defined paths are useful in reducing maneuvering efforts by human. This paper introduces an Elastic Path Controller (EPC) that adds "elasticity" to the path following and enables dynamic modification of the paths. This permits the users to compensate for changes in the environment such as introduction of new obstacles or for errors in position sensing. The experiments performed on a Scooter cobot show that users can learn to use this novel tool to modify and design guiding paths in a relatively simple way. The operators use the EPC by pushing/pulling against the guided paths to produce the desired deformations. Then, by just dropping the forces and trusting the path controller, they will be brought back to the guided paths.

  11. Cooperative path planning of unmanned aerial vehicles

    CERN Document Server

    Tsourdos, Antonios; Shanmugavel, Madhavan

    2010-01-01

    An invaluable addition to the literature on UAV guidance and cooperative control, Cooperative Path Planning of Unmanned Aerial Vehicles is a dedicated, practical guide to computational path planning for UAVs. One of the key issues facing future development of UAVs is path planning: it is vital that swarm UAVs/ MAVs can cooperate together in a coordinated manner, obeying a pre-planned course but able to react to their environment by communicating and cooperating. An optimized path is necessary in order to ensure a UAV completes its mission efficiently, safely, and successfully. Focussing on the path planning of multiple UAVs for simultaneous arrival on target, Cooperative Path Planning of Unmanned Aerial Vehicles also offers coverage of path planners that are applicable to land, sea, or space-borne vehicles. Cooperative Path Planning of Unmanned Aerial Vehicles is authored by leading researchers from Cranfield University and provides an authoritative resource for researchers, academics and engineers working in...

  12. Time optimal paths for high speed maneuvering

    Energy Technology Data Exchange (ETDEWEB)

    Reister, D.B.; Lenhart, S.M.

    1993-01-01

    Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.

  13. On demand polarimetry using a movable microgrid polarizer

    Science.gov (United States)

    King, Page E.; Fest, Eric C.

    2015-09-01

    A movable pixelated filter array is proposed to provide low cost, on demand polarimetry and wavefront sensing. With this concept, an optical system can turn polarimetry on and off by using a shutter to move a microgrid polarizer array in and out of the optical path of the system. This allows an optical system to operate in two modes, a non-polarimetric mode in which sensor range is maintained, and a polarimetric mode in which it is reduced. In implementing this concept, adequate knowledge of the position of the filter in the optical path and calibration procedures become critical topics. This paper discusses simulated and hardware-tested results of this invention.

  14. Accretion-induced spin-wandering effects on the neutron star in Scorpius X-1: Implications for continuous gravitational wave searches

    Science.gov (United States)

    Mukherjee, Arunava; Messenger, Chris; Riles, Keith

    2018-02-01

    The LIGO's discovery of binary black hole mergers has opened up a new era of transient gravitational wave astronomy. The potential detection of gravitational radiation from another class of astronomical objects, rapidly spinning nonaxisymmetric neutron stars, would constitute a new area of gravitational wave astronomy. Scorpius X-1 (Sco X-1) is one of the most promising sources of continuous gravitational radiation to be detected with present-generation ground-based gravitational wave detectors, such as Advanced LIGO and Advanced Virgo. As the sensitivity of these detectors improve in the coming years, so will power of the search algorithms being used to find gravitational wave signals. Those searches will still require integration over nearly year long observational spans to detect the incredibly weak signals from rotating neutron stars. For low mass X-ray binaries such as Sco X-1 this difficult task is compounded by neutron star "spin wandering" caused by stochastic accretion fluctuations. In this paper, we analyze X-ray data from the R X T E satellite to infer the fluctuating torque on the neutron star in Sco X-1. We then perform a large-scale simulation to quantify the statistical properties of spin-wandering effects on the gravitational wave signal frequency and phase evolution. We find that there are a broad range of expected maximum levels of frequency wandering corresponding to maximum drifts of between 0.3 - 50 μ Hz /sec over a year at 99% confidence. These results can be cast in terms of the maximum allowed length of a coherent signal model neglecting spin-wandering effects as ranging between 5-80 days. This study is designed to guide the development and evaluation of Sco X-1 search algorithms.

  15. Path Integral Formulation of Anomalous Diffusion Processes

    OpenAIRE

    Friedrich, Rudolf; Eule, Stephan

    2011-01-01

    We present the path integral formulation of a broad class of generalized diffusion processes. Employing the path integral we derive exact expressions for the path probability densities and joint probability distributions for the class of processes under consideration. We show that Continuous Time Random Walks (CTRWs) are included in our framework. A closed expression for the path probability distribution of CTRWs is found in terms of their waiting time distribution as the solution of a Dyson ...

  16. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    Grueebler, W.

    1984-01-01

    The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

  17. Polarized scintillator targets

    Science.gov (United States)

    van den Brandt, B.; Bunyatova, E. I.; Hautle, P.; Konter, J. A.; Mango, S.

    2000-05-01

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as "live" polarized targets in nuclear physics experiments.

  18. Polarized scintillator targets

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, B. van den E-mail: vandenbrandt@psi.ch; Bunyatova, E.I.; Hautle, P.; Konter, J.A.; Mango, S

    2000-05-21

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as 'live' polarized targets in nuclear physics experiments.

  19. Heidelberg polarized alkali source

    International Nuclear Information System (INIS)

    Kraemer, D.; Steffens, E.; Jaensch, H.; Philipps Universitaet, Marburg, Germany)

    1984-01-01

    A new atomic beam type polarized alkali ion source has been installed at Heidelberg. In order to improve the beam polarization considerably optical pumping is applied in combination with an adiabatic medium field transition which results in beams in single hyperfine sublevels. The m state population is determined by laser-induced fluorescence spectroscopy. Highly polarized beams (P/sub s/ > 0.9, s = z, zz) with intensities of 30 to 130 μA can be extracted for Li + and Na + , respectively

  20. Classical and quantum dynamics from classical paths to path integrals

    CERN Document Server

    Dittrich, Walter

    2016-01-01

    Graduate students who want to become familiar with advanced computational strategies in classical and quantum dynamics will find here both the fundamentals of a standard course and a detailed treatment of the time-dependent oscillator, Chern-Simons mechanics, the Maslov anomaly and the Berry phase, to name a few. Well-chosen and detailed examples illustrate the perturbation theory, canonical transformations, the action principle and demonstrate the usage of path integrals. This new edition has been revised and enlarged with chapters on quantum electrodynamics, high energy physics, Green’s functions and strong interaction.

  1. Polarization measurement in the COMPASS polarized target

    CERN Document Server

    Kondo, K; Baum, G; Berglund, P; Doshita, N; Gautheron, F; Görtz, S; Hasegawa, T; Horikawa, N; Ishimoto, S; Iwata, T; Kisselev, Yu V; Koivuniemi, J H; Le Goff, J M; Magnon, A; Meyer, W; Reicherz, G; Matsuda, T

    2004-01-01

    Continuous wave nuclear magnetic resonance (NMR) is used to determine the target polarization in the COMPASS experiment. The system is made of the so-called Liverpool Q-meters, Yale-cards, and VME modules for data taking and system controlling. In 2001 the NMR coils were embedded in the target material, while in 2002 and 2003 the coils were mounted on the outer surface of the target cells to increase the packing factor of the material. Though the error of the measurement became larger with the outer coils than with the inner coils, we have performed stable measurements throughout the COMPASS run time for 3 years. The maximum polarization was +57% and -53% as the average in the target cells.

  2. Partial Path Column Generation for the ESPPRC

    DEFF Research Database (Denmark)

    Jepsen, Mads Kehlet; Petersen, Bjørn

    This talk introduces a decomposition of the Elementary Shortest Path Problem with Resource Constraints(ESPPRC), where the path is combined by smaller sub paths. We show computational result by comparing different approaches for the decomposition and compare the best of these with existing algorit...

  3. Psychometric Evaluation of Chinese-Language 44-Item and 10-Item Big Five Personality Inventories, Including Correlations with Chronotype, Mindfulness and Mind Wandering.

    Science.gov (United States)

    Carciofo, Richard; Yang, Jiaoyan; Song, Nan; Du, Feng; Zhang, Kan

    2016-01-01

    The 44-item and 10-item Big Five Inventory (BFI) personality scales are widely used, but there is a lack of psychometric data for Chinese versions. Eight surveys (total N = 2,496, aged 18-82), assessed a Chinese-language BFI-44 and/or an independently translated Chinese-language BFI-10. Most BFI-44 items loaded strongly or predominantly on the expected dimension, and values of Cronbach's alpha ranged .698-.807. Test-retest coefficients ranged .694-.770 (BFI-44), and .515-.873 (BFI-10). The BFI-44 and BFI-10 showed good convergent and discriminant correlations, and expected associations with gender (females higher for agreeableness and neuroticism), and age (older age associated with more conscientiousness and agreeableness, and also less neuroticism and openness). Additionally, predicted correlations were found with chronotype (morningness positive with conscientiousness), mindfulness (negative with neuroticism, positive with conscientiousness), and mind wandering/daydreaming frequency (negative with conscientiousness, positive with neuroticism). Exploratory analysis found that the Self-discipline facet of conscientiousness positively correlated with morningness and mindfulness, and negatively correlated with mind wandering/daydreaming frequency. Furthermore, Self-discipline was found to be a mediator in the relationships between chronotype and mindfulness, and chronotype and mind wandering/daydreaming frequency. Overall, the results support the utility of the BFI-44 and BFI-10 for Chinese-language big five personality research.

  4. RELICS OF GALAXY MERGING: OBSERVATIONAL PREDICTIONS FOR A WANDERING MASSIVE BLACK HOLE AND ACCOMPANYING STAR CLUSTER IN THE HALO OF M31

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, Toshihiro [Astronomy Data Center, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Saito, Yuriko [Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), Mitaka, Tokyo 181-8588 (Japan); Miki, Yohei; Mori, Masao, E-mail: ts.kawaguti@nao.ac.jp [Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

    2014-07-01

    Galaxies and massive black holes (BHs) presumably grow via galactic merging events and subsequent BH coalescence. As a case study, we investigate the merging event between the Andromeda galaxy (M31) and a satellite galaxy. We compute the expected observational appearance of the massive BH that was at the center of the satellite galaxy prior to the merger and is currently wandering in the M31 halo. We demonstrate that a radiatively inefficient accretion flow with a bolometric luminosity of a few tens of solar luminosities develops when Hoyle-Lyttleton accretion onto the BH is assumed. We compute the associated broadband spectrum and show that the radio band (observable with EVLA, ALMA, and the Square Kilometre Array) is the best frequency range in which to detect the emission. We also evaluate the mass and the luminosity of the stars bound by the wandering BH and find that such a star cluster is sufficiently luminous that it could correspond to one of the star clusters found by the PAndAS survey. The discovery of a relic massive BH wandering in a galactic halo will provide a direct means of investigating in detail the coevolution of galaxies and BHs. It also means a new population of BHs (off-center massive BHs) and offers targets for clean BH imaging that avoid strong interstellar scattering in the centers of galaxies.

  5. Morphological Adjustment in the Wandering Reach of the Lower Yellow River in Response to the Changes in Water and Sediment Supply over the Recent Decades

    Science.gov (United States)

    Xie, Z.; Huang, H. Q.; Yu, G.

    2017-12-01

    The flow-sediment regime entering into the LYR has changed significantly since the 1970s due to the increasing intensity of human activities. To understand how the wandering reach of the LYR adjusts its channel morphology in response to the change in the flow-sediment regime, this study extracts a series of channel cross-profiles from remote sensing images taken since 1979. It is shown clearly that at one-year timescale, the main flow has shifted significantly, while the sinuosity of the pathways of main flow increased initially, then decreased significantly from 2006 and experienced little variation since 2010. Meanwhile, the width of the wandering belt has been increasing at a very slow stepwise fashion since 2002, and the area of central bars varied with fluctuations before 2009 and yet took a rapidly increasing trend since then. In contrast, the braiding intensity of the wandering reach has shown little change, while the river channel bed and the width/depth ratio of the main channel have taken significant adjustments, with the channel bed being scoured down to a considerable degree and the width/depth ratio varying in a gradually declining trend. These adjustments in the morphology of the Lower Yellow River implicate that the perched situation of the Lower Yellow River can be reversed.

  6. Psychometric Evaluation of Chinese-Language 44-Item and 10-Item Big Five Personality Inventories, Including Correlations with Chronotype, Mindfulness and Mind Wandering

    Science.gov (United States)

    Carciofo, Richard; Yang, Jiaoyan; Song, Nan; Du, Feng; Zhang, Kan

    2016-01-01

    The 44-item and 10-item Big Five Inventory (BFI) personality scales are widely used, but there is a lack of psychometric data for Chinese versions. Eight surveys (total N = 2,496, aged 18–82), assessed a Chinese-language BFI-44 and/or an independently translated Chinese-language BFI-10. Most BFI-44 items loaded strongly or predominantly on the expected dimension, and values of Cronbach's alpha ranged .698-.807. Test-retest coefficients ranged .694-.770 (BFI-44), and .515-.873 (BFI-10). The BFI-44 and BFI-10 showed good convergent and discriminant correlations, and expected associations with gender (females higher for agreeableness and neuroticism), and age (older age associated with more conscientiousness and agreeableness, and also less neuroticism and openness). Additionally, predicted correlations were found with chronotype (morningness positive with conscientiousness), mindfulness (negative with neuroticism, positive with conscientiousness), and mind wandering/daydreaming frequency (negative with conscientiousness, positive with neuroticism). Exploratory analysis found that the Self-discipline facet of conscientiousness positively correlated with morningness and mindfulness, and negatively correlated with mind wandering/daydreaming frequency. Furthermore, Self-discipline was found to be a mediator in the relationships between chronotype and mindfulness, and chronotype and mind wandering/daydreaming frequency. Overall, the results support the utility of the BFI-44 and BFI-10 for Chinese-language big five personality research. PMID:26918618

  7. Limit and frailty: the exercise of chance and self-care in socio-medical training paths

    Directory of Open Access Journals (Sweden)

    Alessandra Augelli

    2014-12-01

    Full Text Available Confronting with the limit and frailty of human existence is inevitable, and in such circumstances, healthcare professionals are often equipped with inadequate theoretical and technical tools. This may result in they having to rely on relational skills, which are by their very nature exposed to the typical risks of the situations they are facing, i.e. unpredictability, misunderstanding, refusal, failure. Criteria of certainty and programmability, which define exact sciences, cannot be transferred into the relationship level, nevertheless, significant resources can result from this gap, through which one can learn how to stay within the limit without hiding or refuting it. The phenomenological perspective, while bringing the focus back to the principle of adherence to the real world and to the transcendence principle, provides a focus on the acceptance of limits, not as sheer elements which cannot be eradicated, but as real spaces for growth and transformation. For this reason, continuing education paths ought to offer spaces where one can consider limit and frailty as chances to reassess experience and become increasingly aware of it together with the others. For their very nature, such paths would promote a productive wandering, intended as an opportunity to open oneself to novelties and to make sense of endless new situations.

  8. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H.B. [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  9. Time Domain Induced Polarization

    DEFF Research Database (Denmark)

    Fiandaca, Gianluca; Auken, Esben; Christiansen, Anders Vest

    2012-01-01

    Time-domain-induced polarization has significantly broadened its field of reference during the last decade, from mineral exploration to environmental geophysics, e.g., for clay and peat identification and landfill characterization. Though, insufficient modeling tools have hitherto limited the use...... of time-domaininduced polarization for wider purposes. For these reasons, a new forward code and inversion algorithm have been developed using the full-time decay of the induced polarization response, together with an accurate description of the transmitter waveform and of the receiver transfer function......%. Furthermore, the presence of low-pass filters in time-domain-induced polarization instruments affects the early times of the acquired decays (typically up to 100 ms) and has to be modeled in the forward response to avoid significant loss of resolution. The developed forward code has been implemented in a 1D...

  10. Polarized proton colliders

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    High energy polarized beam collisions will open up the unique physics opportunities of studying spin effects in hard processes. This will allow the study of the spin structure of the proton and also the verification of the many well documented expectations of spin effects in perturbative QCD and parity violation in W and Z production. Proposals for polarized proton acceleration for several high energy colliders have been developed. A partial Siberian Snake in the AGS has recently been successfully tested and full Siberian Snakes, spin rotators, and polarimeters for RHIC are being developed to make the acceleration of polarized beams to 250 GeV possible. This allows for the unique possibility of colliding two 250 GeV polarized proton beams at luminosities of up to 2 x 10 32 cm -2 s -1

  11. Dual-Polarized Indoor Propagation at 26 GHz

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Pedersen, Gert F.

    2016-01-01

    This work presents results based on wideband radio channel measurements at 26 GHz. Three widely different indoor environments were measured; a cluttered laboratory, a corridor with a bend, and a large entrance hall. Power angular spectra were obtained for both vertical polarization (VP) and horiz......) and horizontal polarization (HP) at many different Rx locations, using both VP or HP for the fixed Tx. The results show that a quite rich channel may exist with several propagation paths. Further, coupling between the VP and HP was found in a non line of sight (NLOS) scenario....

  12. Plasma polarization spectroscopy

    International Nuclear Information System (INIS)

    Iwamae, Atsushi; Horimoto, Yasuhiro; Fujimoto, Takashi; Hasegawa, Noboru; Sukegawa, Kouta; Kawachi, Tetsuya

    2005-01-01

    The electron velocity distribution function (EVDF) in plasma can be anisotropic in laser-produced plasmas. We have developed a new technique to evaluate the polarization degree of the emission lines in the extreme vacuum ultra violet wavelength region. The polarization of the emission lines and the continuums from the lithium-like nitrogen and from helium- and hydrogen-like carbon in recombining plasma is evaluated. Particle simulation in the velocity space gives the time scale for relaxation of anisotropic EVDFs. (author)

  13. Ultracold Polar Molecules

    Science.gov (United States)

    2016-04-01

    AFRL-AFOSR-UK-TR-2016-0005 Ultracold Polar Molecules Jeremy Hutson UNIVERSITY OF DURHAM Final Report 04/01/2016 DISTRIBUTION A: Distribution approved...DATES COVERED (From - To) 15-Jan-2010 to 14-Jul-2015 4. TITLE AND SUBTITLE Final Report on Grant FA8655-10-1-3033 on Ultracold Polar Molecules 5a...formation of ultracold 87RbCs molecules in their rovibrational ground state by magnetoassociation followed by STIRAP, resulting in 14 papers acknowledging

  14. Hsp Polarization Verification

    Science.gov (United States)

    Bless, Robert

    1991-07-01

    This proposal defines the procedure for determining the instrumental polarization of the polarimetric IDT (IDT#1, POL) on the HSP. 1 of 2 unpolarized standard stars wil be observed using various filter-polarizer combinations. These observations will permit the instrumental polarization to be calibrated. The instrumental polarization must be determined to a high precision in order to vectoriallly remove it from HSP polarization observations to determine the actual astronomical polarization. Final run of proposal will look at one of 2 possible stars previously observed to get another look at the throughput. Revision History: Mark H. Slovak 8/30/88 Translated to V2 proposal instructions (RPSS V6.2) S. Laurent 1/20/89 Updated: Sally Laurent 2/24/89, 3/20/89, 4/13/89, 5/12/89 Modified: P. Stanley 1/15/90 - change to use CTA selected targets only; Fixes for aberration problem - SALM 7/30/90; Based on SV/HSP 1386. New submission changed targets and revised scheduling strategy. Revised: 26 Aug 92 J. Dolan, L. Walter, P. Reppert want to re-run the proposal (3985) one last time to bring down errors.

  15. Optical path control in the MAM testbed

    Science.gov (United States)

    Regehr, M. W.; Hines, B.; Holmes, B.

    2003-01-01

    Future space-based optical interferometers will require control of the optical path delay to accomplish some or all of the three objectives: balancing the optical path in the two arms to within a tolerance corresponding to the coherence length of the star light being observed, modulating the optical path in order to observe the phase of the star light interference fringe, and modulating the path length in order to reduce the effect of cyclic errors in the laser metrology system used to measure the optical path length in the two arms of the interferometer.

  16. Two Generations of Path Dependence in Economics?

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

    2010-01-01

    Even if there is no fully articulated and generally accepted theory of Path Dependence it has eagerly been taken up across a wide range of social sciences – primarily coming from economics. Path Dependence is most of all a metaphor that offers reason to believe, that some political, social...... or economic processes have multiple possible paths of outcomes, rather than a unique path of equilibria. The selection among outcomes may depend on contingent choices or events – outcomes of path-dependent processes require a very relevant study – a perception of history....

  17. Path integrals on causal sets

    International Nuclear Information System (INIS)

    Johnston, Steven

    2009-01-01

    We describe a quantum mechanical model for particle propagation on a causal set. The model involves calculating a particle propagator by summing amplitudes assigned to trajectories within the causal set. This 'discrete path integral' is calculated using a matrix geometric series. Amplitudes are given which, when the causal set is generated by sprinkling points into 1+1 or 3+1 Minkowski spacetime, ensure the particle propagator agrees in a suitable sense, with the retarded causal propagator for the Klein-Gordon equation.

  18. Uncommon paths in quantum physics

    CERN Document Server

    Kazakov, Konstantin V

    2014-01-01

    Quantum mechanics is one of the most fascinating, and at the same time most controversial, branches of contemporary science. Disputes have accompanied this science since its birth and have not ceased to this day. Uncommon Paths in Quantum Physics allows the reader to contemplate deeply some ideas and methods that are seldom met in the contemporary literature. Instead of widespread recipes of mathematical physics, based on the solutions of integro-differential equations, the book follows logical and partly intuitional derivations of non-commutative algebra. Readers can directly penetrate the

  19. Welding Robot Collision-Free Path Optimization

    Directory of Open Access Journals (Sweden)

    Xuewu Wang

    2017-02-01

    Full Text Available Reasonable welding path has a significant impact on welding efficiency, and a collision-free path should be considered first in the process of welding robot path planning. The shortest path length is considered as an optimization objective, and obstacle avoidance is considered as the constraint condition in this paper. First, a grid method is used as a modeling method after the optimization objective is analyzed. For local collision-free path planning, an ant colony algorithm is selected as the search strategy. Then, to overcome the shortcomings of the ant colony algorithm, a secondary optimization is presented to improve the optimization performance. Finally, the particle swarm optimization algorithm is used to realize global path planning. Simulation results show that the desired welding path can be obtained based on the optimization strategy.

  20. Polarized Light Microscopy

    Science.gov (United States)

    Frandsen, Athela F.

    2016-01-01

    Polarized light microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarized light microscopy, often

  1. Constrained VPH+: a local path planning algorithm for a bio-inspired crawling robot with customized ultrasonic scanning sensor.

    Science.gov (United States)

    Rao, Akshay; Elara, Mohan Rajesh; Elangovan, Karthikeyan

    This paper aims to develop a local path planning algorithm for a bio-inspired, reconfigurable crawling robot. A detailed description of the robotic platform is first provided, and the suitability for deployment of each of the current state-of-the-art local path planners is analyzed after an extensive literature review. The Enhanced Vector Polar Histogram algorithm is described and reformulated to better fit the requirements of the platform. The algorithm is deployed on the robotic platform in crawling configuration and favorably compared with other state-of-the-art local path planning algorithms.

  2. SSME propellant path leak detection

    Science.gov (United States)

    Crawford, Roger; Shohadaee, Ahmad Ali; Powers, W. T.

    1995-01-01

    The primary objective of this phase of the investigation is the experimental validation of techniques for detecting and analyzing propellant path external leaks which have a high probability of occurring on the SSME. The selection of candidate detection methods requires a good analytic model for leak plumes which would develop from external leaks and an understanding of radiation transfer through the leak plume. One advanced propellant path leak detection technique is obtained by using state-of-art technology of infrared (IR) thermal imaging systems combined with computer, digital image processing and expert systems for the engine protection. The feasibility of the IR leak plume detection will be evaluated on subscale simulated laboratory plumes to determine sensitivity, signal to noise, and general suitability for the application. The theoretical analysis was undertaken with the objective of developing and testing simple, easy-to-use models to predict the amount of radiation coming from a radiation source, background plate (BP), which can be absorbed, emitted and scattered by the gas leaks.

  3. The evolution of tensor polarization

    International Nuclear Information System (INIS)

    Huang, H.; Lee, S.Y.; Ratner, L.

    1993-01-01

    By using the equation of motion for the vector polarization, the spin transfer matrix for spin tensor polarization, the spin transfer matrix for spin tensor polarization is derived. The evolution equation for the tensor polarization is studied in the presence of an isolate spin resonance and in the presence of a spin rotor, or snake

  4. Classical and quantum dynamics from classical paths to path integrals

    CERN Document Server

    Dittrich, Walter

    2017-01-01

    Graduate students who wish to become familiar with advanced computational strategies in classical and quantum dynamics will find in this book both the fundamentals of a standard course and a detailed treatment of the time-dependent oscillator, Chern-Simons mechanics, the Maslov anomaly and the Berry phase, to name just a few topics. Well-chosen and detailed examples illustrate perturbation theory, canonical transformations and the action principle, and demonstrate the usage of path integrals. The fifth edition has been revised and enlarged to include chapters on quantum electrodynamics, in particular, Schwinger’s proper time method and the treatment of classical and quantum mechanics with Lie brackets and pseudocanonical transformations. It is shown that operator quantum electrodynamics can be equivalently described with c-numbers, as demonstrated by calculating the propagation function for an electron in a prescribed classical electromagnetic field.

  5. Temporal focus, temporal distance, and mind-wandering valence: Results from an experience sampling and an experimental study.

    Science.gov (United States)

    Spronken, Maitta; Holland, Rob W; Figner, Bernd; Dijksterhuis, Ap

    2016-04-01

    When mind-wandering, people may think about events that happened in the past, or events that may happen in the future. Using experience sampling, we first aimed to replicate the finding that future-oriented thoughts show a greater positivity bias than past-oriented thoughts. Furthermore, we investigated whether there is a relation between the temporal distance of past- and future-oriented thoughts and the frequency of positive thoughts, a factor that has received little attention in previous work. Second, we experimentally investigated the relation between temporal focus, temporal distance, and thought valence. Both studies showed that future-oriented thoughts were more positive compared to past-oriented thoughts. Regarding temporal distance, thoughts about the distant past and future were more positive than thoughts about the near past and future in the experiment. However, the experience sampling study did not provide clear insight into this relation. Potential theoretical and methodological explanations for these findings are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Efficient algorithm for baseline wander and powerline noise removal from ECG signals based on discrete Fourier series.

    Science.gov (United States)

    Bahaz, Mohamed; Benzid, Redha

    2018-03-01

    Electrocardiogram (ECG) signals are often contaminated with artefacts and noises which can lead to incorrect diagnosis when they are visually inspected by cardiologists. In this paper, the well-known discrete Fourier series (DFS) is re-explored and an efficient DFS-based method is proposed to reduce contribution of both baseline wander (BW) and powerline interference (PLI) noises in ECG records. In the first step, the determination of the exact number of low frequency harmonics contributing in BW is achieved. Next, the baseline drift is estimated by the sum of all associated Fourier sinusoids components. Then, the baseline shift is discarded efficiently by a subtraction of its approximated version from the original biased ECG signal. Concerning the PLI, the subtraction of the contributing harmonics calculated in the same manner reduces efficiently such type of noise. In addition of visual quality results, the proposed algorithm shows superior performance in terms of higher signal-to-noise ratio and smaller mean square error when faced to the DCT-based algorithm.

  7. Heritability of short-scale natal dispersal in a large-scale foraging bird, the wandering albatross.

    Science.gov (United States)

    Charmantier, A; Buoro, M; Gimenez, O; Weimerskirch, H

    2011-07-01

    Natal dispersal is a key life history trait for the evolution and adaptation of wild populations. Although its evolution has repeatedly been related to the social and environmental context faced by individuals, parent-offspring regressions have also highlighted a possible heritable component. In this study, we explore heritability of natal dispersal, at the scale of the sub-Antarctic Possession Island, for a large-scale foraging seabird, the Wandering albatross Diomedea exulans, exploiting a pedigree spanning over four decades and a maximum of four generations. The comparison of three different methods shows that heritability on the liability scale can vary drastically depending on the type of model (heritability from 6% to 86%), with a notable underestimation by restricted maximum likelihood animal models (6%) compared to Bayesian animal models (36%). In all cases, however, our results point to significant additive genetic variance in the individual propensity to disperse, after controlling for substantial effects of sex and natal colony. These results reveal promising evolutionary potential for short-scale natal dispersal, which could play a critical role for the long-term persistence of this species on the long run. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  8. Demographic consequences of heavy metals and persistent organic pollutants in a vulnerable long-lived bird, the wandering albatross.

    Science.gov (United States)

    Goutte, Aurélie; Barbraud, Christophe; Meillère, Alizée; Carravieri, Alice; Bustamante, Paco; Labadie, Pierre; Budzinski, Hélène; Delord, Karine; Cherel, Yves; Weimerskirch, Henri; Chastel, Olivier

    2014-07-22

    Seabirds are top predators of the marine environment that accumulate contaminants over a long life-span. Chronic exposure to pollutants is thought to compromise survival rate and long-term reproductive outputs in these long-lived organisms, thus inducing population decline. However, the demographic consequences of contaminant exposure are largely theoretical because of the dearth of long-term datasets. This study aims to test whether adult survival rate, return to the colony and long-term breeding performance were related to blood mercury (Hg), cadmium (Cd) and persistent organic pollutants (POPs), by using a capture-mark-recapture dataset on the vulnerable wandering albatross Diomedea exulans. We did not find evidence for any effect of contaminants on adult survival probability. However, blood Hg and POPs negatively impacted long-term breeding probability, hatching and fledging probabilities. The proximate mechanisms underlying these deleterious effects are likely multifaceted, through physiological perturbations and interactions with reproductive costs. Using matrix population models, we projected a demographic decline in response to an increase in Hg or POPs concentrations. This decline in population growth rate could be exacerbated by other anthropogenic perturbations, such as climate change, disease and fishery bycatch. This study gives a new dimension to the overall picture of environmental threats to wildlife populations. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  9. Age-related variation in foraging behaviour in the wandering albatross at South Georgia: no evidence for senescence.

    Science.gov (United States)

    Froy, Hannah; Lewis, Sue; Catry, Paulo; Bishop, Charles M; Forster, Isaac P; Fukuda, Akira; Higuchi, Hiroyoshi; Phalan, Ben; Xavier, Jose C; Nussey, Daniel H; Phillips, Richard A

    2015-01-01

    Age-related variation in demographic rates is now widely documented in wild vertebrate systems, and has significant consequences for population and evolutionary dynamics. However, the mechanisms underpinning such variation, particularly in later life, are less well understood. Foraging efficiency is a key determinant of fitness, with implications for individual life history trade-offs. A variety of faculties known to decline in old age, such as muscular function and visual acuity, are likely to influence foraging performance. We examine age-related variation in the foraging behaviour of a long-lived, wide-ranging oceanic seabird, the wandering albatross Diomedea exulans. Using miniaturised tracking technologies, we compared foraging trip characteristics of birds breeding at Bird Island, South Georgia. Based on movement and immersion data collected during the incubation phase of a single breeding season, and from extensive tracking data collected in previous years from different stages of the breeding cycle, we found limited evidence for age-related variation in commonly reported trip parameters, and failed to detect signs of senescent decline. Our results contrast with the limited number of past studies that have examined foraging behaviour in later life, since these have documented changes in performance consistent with senescence. This highlights the importance of studies across different wild animal populations to gain a broader perspective on the processes driving variation in ageing rates.

  10. Demographic consequences of heavy metals and persistent organic pollutants in a vulnerable long-lived bird, the wandering albatross

    Science.gov (United States)

    Goutte, Aurélie; Barbraud, Christophe; Meillère, Alizée; Carravieri, Alice; Bustamante, Paco; Labadie, Pierre; Budzinski, Hélène; Delord, Karine; Cherel, Yves; Weimerskirch, Henri; Chastel, Olivier

    2014-01-01

    Seabirds are top predators of the marine environment that accumulate contaminants over a long life-span. Chronic exposure to pollutants is thought to compromise survival rate and long-term reproductive outputs in these long-lived organisms, thus inducing population decline. However, the demographic consequences of contaminant exposure are largely theoretical because of the dearth of long-term datasets. This study aims to test whether adult survival rate, return to the colony and long-term breeding performance were related to blood mercury (Hg), cadmium (Cd) and persistent organic pollutants (POPs), by using a capture–mark–recapture dataset on the vulnerable wandering albatross Diomedea exulans. We did not find evidence for any effect of contaminants on adult survival probability. However, blood Hg and POPs negatively impacted long-term breeding probability, hatching and fledging probabilities. The proximate mechanisms underlying these deleterious effects are likely multifaceted, through physiological perturbations and interactions with reproductive costs. Using matrix population models, we projected a demographic decline in response to an increase in Hg or POPs concentrations. This decline in population growth rate could be exacerbated by other anthropogenic perturbations, such as climate change, disease and fishery bycatch. This study gives a new dimension to the overall picture of environmental threats to wildlife populations. PMID:24920477

  11. Age-related variation in foraging behaviour in the wandering albatross at South Georgia: no evidence for senescence.

    Directory of Open Access Journals (Sweden)

    Hannah Froy

    Full Text Available Age-related variation in demographic rates is now widely documented in wild vertebrate systems, and has significant consequences for population and evolutionary dynamics. However, the mechanisms underpinning such variation, particularly in later life, are less well understood. Foraging efficiency is a key determinant of fitness, with implications for individual life history trade-offs. A variety of faculties known to decline in old age, such as muscular function and visual acuity, are likely to influence foraging performance. We examine age-related variation in the foraging behaviour of a long-lived, wide-ranging oceanic seabird, the wandering albatross Diomedea exulans. Using miniaturised tracking technologies, we compared foraging trip characteristics of birds breeding at Bird Island, South Georgia. Based on movement and immersion data collected during the incubation phase of a single breeding season, and from extensive tracking data collected in previous years from different stages of the breeding cycle, we found limited evidence for age-related variation in commonly reported trip parameters, and failed to detect signs of senescent decline. Our results contrast with the limited number of past studies that have examined foraging behaviour in later life, since these have documented changes in performance consistent with senescence. This highlights the importance of studies across different wild animal populations to gain a broader perspective on the processes driving variation in ageing rates.

  12. Polarized Electrons at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1997-12-31

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously.initial operational experience with the polarized source will be presented.

  13. Polarized electrons at Jefferson laboratory

    International Nuclear Information System (INIS)

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously. Initial operational experience with the polarized source will be presented

  14. Polar low monitoring

    Science.gov (United States)

    Bobylev, Leonid; Zabolotskikh, Elizaveta; Mitnik, Leonid

    2010-05-01

    Polar lows are intense mesoscale atmospheric low pressure weather systems, developing poleward of the main baroclinic zone and associated with high surface wind speeds. Small size and short lifetime, sparse in-situ observations in the regions of their development complicate polar low study. Our knowledge of polar lows and mesocyclones has come almost entirely during the period of satellite remote sensing since, by virtue of their small horizontal scale, it was rarely possible to analyse these lows on conventional weather charts using only the data from the synoptic observing network. However, the effects of intense polar lows have been felt by coastal communities and seafarers since the earliest times. These weather systems are thought to be responsible for the loss of many small vessels over the centuries, although the nature of the storms was not understood and their arrival could not be predicted. The actuality of the polar low research is stipulated by their high destructive power: they are a threat to such businesses as oil and gas exploration, fisheries and shipping. They could worsen because of global warming: a shrinking of sea ice around the North Pole, which thawed to its record minimum in the summer of 2007, is likely to give rise to more powerful storms that form only over open water and can cause hurricane-strength winds. Therefore, study of polar lows, their timely detection, tracking and forecasting represents a challenge for today meteorology. Satellite passive microwave data, starting from Special Sensor Microwave Imager (SSM/I) onboard Defense Meteorological Satellite Program (DMSP) satellite, remain invaluable source of regularly available remotely sensed data to study polar lows. The sounding in this spectral range has several advantages in comparison with observations in visible and infrared ranges and Synthetic Aperture Radar (SAR) data: independence on day time and clouds, regularity and high temporal resolution in Polar Regions. Satellite

  15. Effectiveness of interactive tutorials in promoting "which-path" information reasoning in advanced quantum mechanics

    Science.gov (United States)

    Maries, Alexandru; Sayer, Ryan; Singh, Chandralekha

    2017-12-01

    Research suggests that introductory physics students often have difficulty using a concept in contexts different from the ones in which they learned it without explicit guidance to help them make the connection between the different contexts. We have been investigating advanced students' learning of quantum mechanics concepts and have developed interactive tutorials which strive to help students learn these concepts. Two such tutorials, focused on the Mach-Zehnder interferometer (MZI) and the double-slit experiment (DSE), help students learn how to use the concept of "which-path" information to reason about the presence or absence of interference in these two experiments in different situations. After working on a pretest that asked students to predict interference in the MZI with single photons and polarizers of various orientations placed in one or both paths of the MZI, students worked on the MZI tutorial which, among other things, guided them to reason in terms of which-path information in order to predict interference in similar situations. We investigated the extent to which students were able to use reasoning related to which-path information learned in the MZI tutorial to answer analogous questions on the DSE (before working on the DSE tutorial). After students worked on the DSE pretest they worked on a DSE tutorial in which they learned to use the concept of which-path information to answer questions about interference in the DSE with single particles with mass sent through the two slits and a monochromatic lamp placed between the slits and the screen. We investigated if this additional exposure to the concept of which-path information promoted improved learning and performance on the DSE questions with single photons and polarizers placed after one or both slits. We find evidence that both tutorials promoted which-path information reasoning and helped students use this reasoning appropriately in contexts different from the ones in which they had learned

  16. Polarized protons at RHIC

    International Nuclear Information System (INIS)

    Tannenbaum, M.J.

    1990-12-01

    The Physics case is presented for the use of polarized protons at RHIC for one or two months each year. This would provide a facility with polarizations of approx-gt 50% high luminosity ∼2.0 x 10 32 cm -2 s -1 , the possibility of both longitudinal and transverse polarization at the interaction regions, and frequent polarization reversal for control of systematic errors. The annual integrated luminosity for such running (∼10 6 sec per year) would be ∫ Ldt = 2 x 10 38 cm -2 -- roughly 20 times the total luminosity integrated in ∼ 10 years of operation of the CERN Collider (∼10 inverse picobarns, 10 37 cm -2 ). This facility would be unique in the ability to perform parity-violating measurements and polarization test of QCD. Also, the existence of p-p collisions in a new energy range would permit the study of ''classical'' reactions like the total cross section and elastic scattering, etc., and serve as a complement to measurements from p-bar p colliders. 11 refs

  17. The Bochum Polarized Target

    International Nuclear Information System (INIS)

    Reicherz, G.; Goertz, S.; Harmsen, J.; Heckmann, J.; Meier, A.; Meyer, W.; Radtke, E.

    2001-01-01

    The Bochum 'Polarized Target' group develops the target material 6 LiD for the COMPASS experiment at CERN. Several different materials like alcohols, alcanes and ammonia are under investigation. Solid State Targets are polarized in magnetic fields higher than B=2.5T and at temperatures below T=1K. For the Dynamic Nuclear Polarization process, paramagnetic centers are induced chemically or by irradiation with ionizing beams. The radical density is a critical factor for optimization of polarization and relaxation times at adequate magnetic fields and temperatures. In a high sensitive EPR--apparatus, an evaporator and a dilution cryostat with a continuous wave NMR--system, the materials are investigated and optimized. To improve the polarization measurement, the Liverpool NMR-box is modified by exchanging the fixed capacitor for a varicap diode which not only makes the tuning very easy but also provides a continuously tuned circuit. The dependence of the signal area upon the circuit current is measured and it is shown that it follows a linear function

  18. Pathfinder: Visual Analysis of Paths in Graphs

    Science.gov (United States)

    Partl, C.; Gratzl, S.; Streit, M.; Wassermann, A. M.; Pfister, H.; Schmalstieg, D.; Lex, A.

    2016-01-01

    The analysis of paths in graphs is highly relevant in many domains. Typically, path-related tasks are performed in node-link layouts. Unfortunately, graph layouts often do not scale to the size of many real world networks. Also, many networks are multivariate, i.e., contain rich attribute sets associated with the nodes and edges. These attributes are often critical in judging paths, but directly visualizing attributes in a graph layout exacerbates the scalability problem. In this paper, we present visual analysis solutions dedicated to path-related tasks in large and highly multivariate graphs. We show that by focusing on paths, we can address the scalability problem of multivariate graph visualization, equipping analysts with a powerful tool to explore large graphs. We introduce Pathfinder (Figure 1), a technique that provides visual methods to query paths, while considering various constraints. The resulting set of paths is visualized in both a ranked list and as a node-link diagram. For the paths in the list, we display rich attribute data associated with nodes and edges, and the node-link diagram provides topological context. The paths can be ranked based on topological properties, such as path length or average node degree, and scores derived from attribute data. Pathfinder is designed to scale to graphs with tens of thousands of nodes and edges by employing strategies such as incremental query results. We demonstrate Pathfinder's fitness for use in scenarios with data from a coauthor network and biological pathways. PMID:27942090

  19. Pathfinder: Visual Analysis of Paths in Graphs.

    Science.gov (United States)

    Partl, C; Gratzl, S; Streit, M; Wassermann, A M; Pfister, H; Schmalstieg, D; Lex, A

    2016-06-01

    The analysis of paths in graphs is highly relevant in many domains. Typically, path-related tasks are performed in node-link layouts. Unfortunately, graph layouts often do not scale to the size of many real world networks. Also, many networks are multivariate, i.e., contain rich attribute sets associated with the nodes and edges. These attributes are often critical in judging paths, but directly visualizing attributes in a graph layout exacerbates the scalability problem. In this paper, we present visual analysis solutions dedicated to path-related tasks in large and highly multivariate graphs. We show that by focusing on paths, we can address the scalability problem of multivariate graph visualization, equipping analysts with a powerful tool to explore large graphs. We introduce Pathfinder (Figure 1), a technique that provides visual methods to query paths, while considering various constraints. The resulting set of paths is visualized in both a ranked list and as a node-link diagram. For the paths in the list, we display rich attribute data associated with nodes and edges, and the node-link diagram provides topological context. The paths can be ranked based on topological properties, such as path length or average node degree, and scores derived from attribute data. Pathfinder is designed to scale to graphs with tens of thousands of nodes and edges by employing strategies such as incremental query results. We demonstrate Pathfinder's fitness for use in scenarios with data from a coauthor network and biological pathways.

  20. In-line Fiber Polarizer

    OpenAIRE

    Perumalsamy, Priya

    1998-01-01

    Polarizers and polarization devices are important components in fiber optic communication and sensor systems. There is a growing need for efficient low loss components that are compatible with optical fibers. An all fiber in-line polarizer is a more desirable alternative that could be placed at appropriate intervals along communication links. An in-line fiber polarizer was fabricated and tested. The in-line fiber polarizer operates by coupling optical energy propagatin...

  1. Integrated assignment and path planning

    Science.gov (United States)

    Murphey, Robert A.

    2005-11-01

    A surge of interest in unmanned systems has exposed many new and challenging research problems across many fields of engineering and mathematics. These systems have the potential of transforming our society by replacing dangerous and dirty jobs with networks of moving machines. This vision is fundamentally separate from the modern view of robotics in that sophisticated behavior is realizable not by increasing individual vehicle complexity, but instead through collaborative teaming that relies on collective perception, abstraction, decision making, and manipulation. Obvious examples where collective robotics will make an impact include planetary exploration, space structure assembly, remote and undersea mining, hazardous material handling and clean-up, and search and rescue. Nonetheless, the phenomenon driving this technology trend is the increasing reliance of the US military on unmanned vehicles, specifically, aircraft. Only a few years ago, following years of resistance to the use of unmanned systems, the military and civilian leadership in the United States reversed itself and have recently demonstrated surprisingly broad acceptance of increasingly pervasive use of unmanned platforms in defense surveillance, and even attack. However, as rapidly as unmanned systems have gained acceptance, the defense research community has discovered the technical pitfalls that lie ahead, especially for operating collective groups of unmanned platforms. A great deal of talent and energy has been devoted to solving these technical problems, which tend to fall into two categories: resource allocation of vehicles to objectives, and path planning of vehicle trajectories. An extensive amount of research has been conducted in each direction, yet, surprisingly, very little work has considered the integrated problem of assignment and path planning. This dissertation presents a framework for studying integrated assignment and path planning and then moves on to suggest an exact

  2. The Chinese path to individualization.

    Science.gov (United States)

    Yan, Yunxiang

    2010-09-01

    This article explores the rise of the individual and the consequential individualization of society which should be viewed as a reflexive part of China's state-sponsored quest for modernity. It traces the origin of the individualization process to the Maoist era, arguing that some collectivist programmes of social engineering and the socialist path of modernization under Maoism ironically resulted in a partial individualization of Chinese society. Examining profound social changes during the three decades of the post-Mao reforms, the article reveals a number of similarities with the individualization process in Western Europe but also demonstrates some important differences. In the last section, the theoretical implications of the Chinese case in light of Ulrich Beck's theory of individualization and second modernity are discussed. © London School of Economics and Political Science 2010.

  3. Counting paths with Schur transitions

    Energy Technology Data Exchange (ETDEWEB)

    Díaz, Pablo [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, Alberta, T1K 3M4 (Canada); Kemp, Garreth [Department of Physics, University of Johannesburg, P.O. Box 524, Auckland Park 2006 (South Africa); Véliz-Osorio, Alvaro, E-mail: aveliz@gmail.com [Mandelstam Institute for Theoretical Physics, University of the Witwatersrand, WITS 2050, Johannesburg (South Africa); School of Physics and Astronomy, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom)

    2016-10-15

    In this work we explore the structure of the branching graph of the unitary group using Schur transitions. We find that these transitions suggest a new combinatorial expression for counting paths in the branching graph. This formula, which is valid for any rank of the unitary group, reproduces known asymptotic results. We proceed to establish the general validity of this expression by a formal proof. The form of this equation strongly hints towards a quantum generalization. Thus, we introduce a notion of quantum relative dimension and subject it to the appropriate consistency tests. This new quantity finds its natural environment in the context of RCFTs and fractional statistics; where the already established notion of quantum dimension has proven to be of great physical importance.

  4. Political Competition and Polarization

    DEFF Research Database (Denmark)

    Schultz, Christian

    This paper considers political competition and the consequences of political polarization when parties are better informed about how the economy functions than voters are. Specifically, parties know the cost producing a public good, voters do not. An incumbent's choice of policy acts like a signa...... for costs before an upcoming election. It is shown that the more polarized the political parties the more distorted the incumbent's policy choice.......This paper considers political competition and the consequences of political polarization when parties are better informed about how the economy functions than voters are. Specifically, parties know the cost producing a public good, voters do not. An incumbent's choice of policy acts like a signal...

  5. Physics of polarized targets

    CERN Document Server

    Niinikoski, Tapio

    2014-01-01

    For developing, building and operating solid polarized targets we need to understand several fields of physics that have seen sub stantial advances during the last 50 years. W e shall briefly review a selection of those that are important today. These are: 1) quantum statistical methods to describe saturation and relaxation in magnetic resonance; 2) equal spin temperature model for dy namic nuclear polarization; 3 ) weak saturation during NMR polarization measurement; 4 ) refrigeration using the quantum fluid properties of helium isotopes. These, combined with superconducting magnet technologies, permit today to reach nearly complete pola rization of almost any nuclear spins. Targets can be operated in frozen spin mode in rather low and inhomogeneous field of any orientation, and in DNP mode in beams of high intensity. Beyond such experiments of nuclear and particle physics, applications a re also emerging in macromolecular chemistry and in magnetic resonance imaging. This talk is a tribute to Michel Borghini...

  6. No More Polarization, Please!

    DEFF Research Database (Denmark)

    Hansen, Mia Reinholt

    The organizational science literature on motivation has for long been polarized into two main positions; the organizational economic position focusing on extrinsic motivation and the organizational behavior position emphasizing intrinsic motivation. With the rise of the knowledge economy...... and the increasing levels of complexities it entails, such polarization is not fruitful in the attempt to explain motivation of organizational members. This paper claims that a more nuanced perspective on motivation, acknowledging the co-existence of intrinsic and extrinsic motivation, the possible interaction...... between the two as well as different types of motivations filling in the gap between the two polar types, is urgently needed in the organizational science literature. By drawing on the research on intrinsic and extrinsic motivation conducted in social psychology and combining this with contributions from...

  7. Polarized source upgrading

    International Nuclear Information System (INIS)

    Clegg, T.B.; Rummel, R.L.; Carter, E.P.; Westerfeldt, C.R.; Lovette, A.W.; Edwards, S.E.

    1985-01-01

    The decision was made this past year to move the Lamb-shift polarized ion source which was first installed in the laboratory in 1970. The motivation was the need to improve the flexibility of spin-axis orientation by installing the ion source with a new Wien-filter spin precessor which is capable of rotating physically about the beam axis. The move of the polarized source was accomplished in approximately two months, with the accelerator being turned off for experiments during approximately four weeks of this time. The occasion of the move provided the opportunity to rewire completely the entire polarized ion source frame and to rebuild approximately half of the electronic chassis on the source. The result is an ion source which is now logically wired and carefully documented. Beams obtained from the source are much more stable than those previously available

  8. A lunar polar expedition

    Science.gov (United States)

    Dowling, Richard; Staehle, Robert L.; Svitek, Tomas

    1992-09-01

    Advanced exploration and development in harsh environments require mastery of basic human survival skill. Expeditions into the lethal climates of Earth's polar regions offer useful lessons for tommorrow's lunar pioneers. In Arctic and Antarctic exploration, 'wintering over' was a crucial milestone. The ability to establish a supply base and survive months of polar cold and darkness made extensive travel and exploration possible. Because of the possibility of near-constant solar illumination, the lunar polar regions, unlike Earth's may offer the most hospitable site for habitation. The World Space Foundation is examining a scenario for establishing a five-person expeditionary team on the lunar north pole for one year. This paper is a status report on a point design addressing site selection, transportation, power, and life support requirements.

  9. Dual-polarization interference microscopy for advanced quantification of phase associated with the image field.

    Science.gov (United States)

    Bouchal, Petr; Chmelík, Radim; Bouchal, Zdeněk

    2018-02-01

    A new concept of dual-polarization spatial light interference microscopy (DPSLIM) is proposed and demonstrated experimentally. The method works with two orthogonally polarized modes in which signal and reference waves are combined to realize the polarization-sensitive phase-shifting, thus allowing advanced reconstruction of the phase associated with the image field. The image phase is reconstructed directly from four polarization encoded interference records by a single step processing. This is a progress compared with common methods, in which the phase of the image field is reconstructed using the optical path difference and the amplitudes of interfering waves, which are calculated in multiple-step processing of the records. The DPSLIM is implemented in a common-path configuration using a spatial light modulator, which is connected to a commercial microscope Nikon E200. The optical performance of the method is demonstrated in experiments using both polystyrene microspheres and live LW13K2 cells.

  10. POLARIZED NEUTRONS IN RHIC

    Energy Technology Data Exchange (ETDEWEB)

    COURANT,E.D.

    1998-04-27

    There does not appear to be any obvious way to accelerate neutrons, polarized or otherwise, to high energies by themselves. To investigate the behavior of polarized neutrons the authors therefore have to obtain them by accelerating them as components of heavier nuclei, and then sorting out the contribution of the neutrons in the analysis of the reactions produced by the heavy ion beams. The best neutron carriers for this purpose are probably {sup 3}He nuclei and deuterons. A polarized deuteron is primarily a combination of a proton and a neutron with their spins pointing in the same direction; in the {sup 3}He nucleus the spins of the two protons are opposite and the net spin (and magnetic moment) is almost the same as that of a free neutron. Polarized ions other than protons may be accelerated, stored and collided in a ring such as RHIC provided the techniques proposed for polarized proton operation can be adapted (or replaced by other strategies) for these ions. To accelerate polarized particles in a ring, one must make provisions for overcoming the depolarizing resonances that occur at certain energies. These resonances arise when the spin tune (ratio of spin precession frequency to orbit frequency) resonates with a component present in the horizontal field. The horizontal field oscillates with the vertical motion of the particles (due to vertical focusing); its frequency spectrum is dominated by the vertical oscillation frequency and its modulation by the periodic structure of the accelerator ring. In addition, the magnet imperfections that distort the closed orbit vertically contain all integral Fourier harmonics of the orbit frequency.

  11. Wavelength Dependence of the Polarization Singularities in a Two-Mode Optical Fiber

    Directory of Open Access Journals (Sweden)

    V. V. G. Krishna Inavalli

    2012-01-01

    Full Text Available We present here an experimental demonstration of the wavelength dependence of the polarization singularities due to linear combination of the vector modes excited directly in a two-mode optical fiber. The coherent superposition of the vector modes excited by linearly polarized Gaussian beam as offset skew rays propagated in a helical path inside the fiber results in the generation of phase singular beams with edge dislocation in the fiber output. The polarization character of these beams is found to change dramatically with wavelength—from left-handed elliptically polarized edge dislocation to right-handed elliptically polarized edge-dislocation through disclinations. The measured behaviour is understood as being due to intermodal dispersion of the polarization corrections to the propagating vector modes, as the wavelength of the input beam is scanned.

  12. Polarization Beam Splitter Based on a Self-Collimation Michelson Interferometer in a Silicon Photonic Crystal

    International Nuclear Information System (INIS)

    Chen Xi-Yao; Lin Gui-Min; Li Jun-Jun; Xu Xiao-Fu; Jiang Jun-Zhen; Qiang Ze-Xuan; Qiu Yi-Shen; Li Hui

    2012-01-01

    A polarization beam splitter based on a self-collimation Michelson interferometer (SMI) in a hole-type silicon photonic crystal is proposed and numerically demonstrated. Utilizing the polarization dependence of the transmission spectra of the SMI and polarization peak matching method, the SMI can work as a polarization beam splitter (PBS) by selecting an appropriate path length difference in the structure. Based on its novel polarization beam splitting mechanics, the polarization extinction ratios (PERs) for TM and TE modes are as high as 18.4 dB and 24.3 dB, respectively. Since its dimensions are only several operating wavelengths, the PBS may have practical applications in photonic integrated circuits. (fundamental areas of phenomenology(including applications))

  13. Dark Polar Dunes

    Science.gov (United States)

    2005-01-01

    20 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image, acquired during northern summer in December 2004, shows dark, windblown sand dunes in the north polar region of Mars. A vast sea of sand dunes nearly surrounds the north polar cap. These landforms are located near 80.3oN, 144.1oW. Light-toned features in the image are exposures of the substrate that underlies the dune field. The image covers an area about 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  14. Imaging with Polarized Neutrons

    Directory of Open Access Journals (Sweden)

    Nikolay Kardjilov

    2018-01-01

    Full Text Available Owing to their zero charge, neutrons are able to pass through thick layers of matter (typically several centimeters while being sensitive to magnetic fields due to their intrinsic magnetic moment. Therefore, in addition to the conventional attenuation contrast image, the magnetic field inside and around a sample can be visualized by detecting changes of polarization in a transmitted beam. The method is based on the spatially resolved measurement of the cumulative precession angles of a collimated, polarized, monochromatic neutron beam that traverses a magnetic field or sample.

  15. The polar mesosphere

    International Nuclear Information System (INIS)

    Morris, Ray; Murphy, Damian

    2008-01-01

    The mesosphere region, which lies at the edge of space, contains the coldest layer of the Earth's atmosphere, with summer temperatures as low as minus 130 °C. In this extreme environment ice aerosol layers have appeared since the dawn of industrialization—whose existence may arguably be linked to human influence—on yet another layer of the Earth's fragile atmosphere. Ground-based and space-based experiments conducted in the Arctic and Antarctic during the International Polar Year (IPY) aim to address limitations in our knowledge and to advance our understanding of thermal and dynamical processes at play in the polar mesosphere

  16. Internal polarized targets

    Energy Technology Data Exchange (ETDEWEB)

    Kinney, E.R.; Coulter, K.; Gilman, R.; Holt, R.J.; Kowalczyk, R.S.; Napolitano, J.; Potterveld, D.H.; Young, L. (Argonne National Lab., IL (USA)); Mishnev, S.I.; Nikolenko, D.M.; Popov, S.G.; Rachek, I.A.; Temnykh, A.B.; Toporkov, D.K.; Tsentalovich, E.P.; Wojtsekhowski, B.B. (AN SSSR, Novosibirsk (USSR). Inst. Yadernoj Fiziki)

    1989-01-01

    Internal polarized targets offer a number of advantages over external targets. After a brief review of the basic motivation and principles behind internal polarized targets, the technical aspects of the atomic storage cell will be discussed in particular. Sources of depolarization and the means by which their effects can be ameliorated will be described, especially depolarization by the intense magnetic fields arising from the circulating particle beam. The experience of the Argonne Novosibirsk collaboration with the use of a storage cell in a 2 GeV electron storage ring will be the focus of this technical discussion. 17 refs., 11 figs.

  17. AGS polarized H- source

    International Nuclear Information System (INIS)

    Kponou, A.; Alessi, J.G.; Sluyters, T.

    1985-01-01

    The AGS polarized H - source is now operational. During a month-long experimental physics run in July 1984, pulses equivalent to 15 μA x 300 μs (approx. 3 x 10 10 protons) were injected into the RFQ preaccelerator. Beam polarization, measured at 200 MeV, was approx. 75%. After the run, a program to increase the H - yield of the source was begun and significant progress has been made. The H - current is now frequently 20 to 30 μA. A description of the source and some details of our operating experience are given. We also briefly describe the improvement program

  18. Strategic Team AI Path Plans: Probabilistic Pathfinding

    Directory of Open Access Journals (Sweden)

    Tng C. H. John

    2008-01-01

    Full Text Available This paper proposes a novel method to generate strategic team AI pathfinding plans for computer games and simulations using probabilistic pathfinding. This method is inspired by genetic algorithms (Russell and Norvig, 2002, in that, a fitness function is used to test the quality of the path plans. The method generates high-quality path plans by eliminating the low-quality ones. The path plans are generated by probabilistic pathfinding, and the elimination is done by a fitness test of the path plans. This path plan generation method has the ability to generate variation or different high-quality paths, which is desired for games to increase replay values. This work is an extension of our earlier work on team AI: probabilistic pathfinding (John et al., 2006. We explore ways to combine probabilistic pathfinding and genetic algorithm to create a new method to generate strategic team AI pathfinding plans.

  19. Crack path morphology in dual phase steel

    International Nuclear Information System (INIS)

    Sarwar, M.

    1995-01-01

    The crack path morphology in low carbon, low alloy dual phase steel has been investigated. Thermomechanical processing and inter critical heat treatments were used to vary proportion, morphology, and distribution of the ferrite and martensite phases. The tortuous morphology of crack path was observed in unrolled material at high delta K. In thermo mechanically processed material, the crack tended to cross martensite frequently and crack path become less circuitous. (author)

  20. Design of Active N-path Filters

    NARCIS (Netherlands)

    Darvishi, M.; van der Zee, Ronan A.R.; Nauta, Bram

    2013-01-01

    A design methodology for synthesis of active N-path bandpass filters is introduced. Based on this methodology, a 0.1-to-1.2 GHz tunable 6th-order N-path channel-select filter in 65 nm LP CMOS is introduced. It is based on coupling N-path filters with gyrators, achieving a “flat‿ passband shape and

  1. The physics of polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    This course is intended to give a description of the basic physical concepts which underlie the study and the interpretation of polarization phenomena. Apart from a brief historical introduction (Sect. 1), the course is organized in three parts. A first part (Sects. 2 - 6) covers the most relevant facts about the polarization phenomena that are typically encountered in laboratory applications and in everyday life. In Sect. 2, the modern description of polarization in terms of the Stokes parameters is recalled, whereas Sect. 3 is devoted to introduce the basic tools of laboratory polarimetry, such as the Jones calculus and the Mueller matrices. The polarization phenomena which are met in the reflection and refraction of a beam of radiation at the separation surface between two dielectrics, or between a dielectric and a metal, are recalled in Sect. 4. Finally, Sect. 5 gives an introduction to the phenomena of dichroism and of anomalous dispersion and Sect. 6 summarizes the polarization phenomena that are commonly encountered in everyday life. The second part of this course (Sects. 7-14) deals with the description, within the formalism of classical physics, of the spectro-polarimetric properties of the radiation emitted by accelerated charges. Such properties are derived by taking as starting point the Liénard and Wiechert equations that are recalled and discussed in Sect. 7 both in the general case and in the non-relativistic approximation. The results are developed to find the percentage polarization, the radiation diagram, the cross-section and the spectral characteristics of the radiation emitted in different phenomena particularly relevant from the astrophysical point of view. The emission of a linear antenna is derived in Sect. 8. The other Sections are devoted to Thomson scattering (Sect. 9), Rayleigh scattering (Sect. 10), Mie scattering (Sect. 11), bremsstrahlung radiation (Sect. 12), cyclotron radiation (Sect. 13), and synchrotron radiation (Sect. 14

  2. Polarized Proton Collisions at RHIC

    CERN Document Server

    Bai, Mei; Alekseev, Igor G; Alessi, James; Beebe-Wang, Joanne; Blaskiewicz, Michael; Bravar, Alessandro; Brennan, Joseph M; Bruno, Donald; Bunce, Gerry; Butler, John J; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Laster, Jonathan S; Lee, Roger C; Luccio, Alfredo U; Luo, Yun; MacKay, William W; Makdisi, Yousef; Marr, Gregory J; Marusic, Al; McIntyre, Gary; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oddo, Peter; Oerter, Brian; Osamu, Jinnouchi; Pilat, Fulvia Caterina; Ptitsyn, Vadim; Roser, Thomas; Satogata, Todd; Smith, Kevin T; Svirida, Dima; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Wilinski, Michelle; Zaltsman, Alex; Zelenski, Anatoli; Zeno, Keith; Zhang, S Y

    2005-01-01

    The Relativistic Heavy Ion Collider~(RHIC) provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC to avoid depolarizing resonances. In 2003, polarized proton beams were accelerated to 100~GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. RHIC polarized proton run experience demonstrates that optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limite...

  3. In-line optical fiber metallic mirror reflector for monolithic common path optical coherence tomography probes.

    Science.gov (United States)

    Singh, Kanwarpal; Reddy, Rohith; Sharma, Gargi; Verma, Yogesh; Gardecki, Joseph A; Tearney, Guillermo

    2018-03-01

    Endoscopic optical coherence tomography probes suffer from various artifacts due to dispersion imbalance and polarization mismatch between reference and sample arm light. Such artifacts can be minimized using a common path approach. In this work, we demonstrate a miniaturized common path probe for optical coherence tomography using an inline fiber mirror. A common path optical fiber probe suitable for performing high-resolution endoscopic optical coherence tomography imaging was developed. To achieve common path functionality, an inline fiber mirror was fabricated using a thin gold layer. A commercially available swept source engine was used to test the designed probe in a cadaver human coronary artery ex vivo. We achieved a sensitivity of 104 dB for this probe using a swept source optical coherence tomography system. To test the probe, images of a cadaver human coronary artery were obtained, demonstrating the quality that is comparable to those obtained by OCT systems with separate reference arms. Additionally, we demonstrate recovery of ranging depth by use of a Michelson interferometer in the detection path. We developed a miniaturized monolithic inline fiber mirror-based common path probe for optical coherence tomography. Owing to its simplicity, our design will be helpful in endoscopic applications that require high-resolution probes in a compact form factor while reducing system complexity. Lasers Surg. Med. 50:230-235, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  4. Path integrals for arbitrary canonical transformations

    International Nuclear Information System (INIS)

    Oliveira, L.A.R. de.

    1980-01-01

    Some aspects of the path integral formulation of quantum mechanics are studied. This formalism is generalized to arbitrary canonical transformations, by means of an association between path integral probalility amplitudes and classical generators of transformations, analogous to the usual Hamiltonian time development phase space expression. Such association turns out to be equivalent to the Weyl quantization rule, and it is also shown that this formalism furnishes a path integral representation for a Lie algebra of a given set of classical generators. Some physical considerations about the path integral quantization procedure and about the relationship between classical and quantum dynamical structures are also discussed. (Author) [pt

  5. Techniques and applications of path integration

    CERN Document Server

    Schulman, L S

    2005-01-01

    A book of techniques and applications, this text defines the path integral and illustrates its uses by example. It is suitable for advanced undergraduates and graduate students in physics; its sole prerequisite is a first course in quantum mechanics. For applications requiring specialized knowledge, the author supplies background material.The first part of the book develops the techniques of path integration. Topics include probability amplitudes for paths and the correspondence limit for the path integral; vector potentials; the Ito integral and gauge transformations; free particle and quadra

  6. Path integrals and geometry of trajectories

    International Nuclear Information System (INIS)

    Blau, M.; Keski-Vakkuri, E.; Niemi, A.J.

    1990-01-01

    A geometrical interpretation of path integrals is developed in the space of trajectories. This yields a supersymmetric formulation of a generic path integral, with the supersymmetry resembling the BRST supersymmetry of a first class constrained system. If the classical equation of motion is a Killing vector field in the space of trajectories, the supersymmetry localizes the path integral to classical trajectories and the WKB approximation becomes exact. This can be viewed as a path integral generalization of the Duistermaat-Heckman theorem, which states the conditions for the exactness of the WKB approximation for integrals in a compact phase space. (orig.)

  7. Symbolic PathFinder v7

    DEFF Research Database (Denmark)

    Luckow, Kasper Søe; Păsăreanu, Corina

    2014-01-01

    We describe Symbolic PathFinder v7 in terms of its updated design addressing the changes of Java PathFinder v7 and of its new optimization when computing path conditions. Furthermore, we describe the Symbolic Execution Tree Extension; a newly added feature that allows for outputting the symbolic...... execution tree that characterizes the execution paths covered during symbolic execution. The new extension can be tailored to the needs of subsequent analyses/processing facilities, and we demonstrate this by presenting SPF-Visualizer, which is a tool for customizable visualization of the symbolic execution...

  8. X-Parameter Based Modelling of Polar Modulated Power Amplifiers

    DEFF Research Database (Denmark)

    Wang, Yelin; Nielsen, Troels Studsgaard; Sira, Daniel

    2013-01-01

    X-parameters are developed as an extension of S-parameters capable of modelling non-linear devices driven by large signals. They are suitable for devices having only radio frequency (RF) and DC ports. In a polar power amplifier (PA), phase and envelope of the input modulated signal are applied...... at separate ports and the envelope port is neither an RF nor a DC port. As a result, X-parameters may fail to characterise the effect of the envelope port excitation and consequently the polar PA. This study introduces a solution to the problem for a commercial polar PA. In this solution, the RF-phase path...... PA for simulations. The simulated error vector magnitude (EVM) and adjacent channel power ratio (ACPR) were compared with the measured data to validate the model. The maximum differences between the simulated and measured EVM and ACPR are less than 2% point and 3 dB, respectively....

  9. Lobbying and political polarization

    OpenAIRE

    Ursprung, Heinrich W.

    2002-01-01

    Standard spatial models of political competition give rise to equilibria in which the competing political parties or candidates converge to a common position. In this paper I show how political polarization can be generated in models that focus on the nexus between pre-election interest group lobbying and electoral competition.

  10. Polarization of Bremsstrahlung

    International Nuclear Information System (INIS)

    Miller, J.

    1957-01-01

    The numerical results for the polarization of Bremsstrahlung are presented. The multiple scattering of electrons in the target is taken into account. The angular-and photon energy dependences are seen on the curves for an incident 25 MeV electron energy. (Author) [fr

  11. DESY: HERA polarization

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization

  12. Titan Polar Landscape Evolution

    Science.gov (United States)

    Moore, Jeffrey M.

    2016-01-01

    With the ongoing Cassini-era observations and studies of Titan it is clear that the intensity and distribution of surface processes (particularly fluvial erosion by methane and Aeolian transport) has changed through time. Currently however, alternate hypotheses substantially differ among specific scenarios with respect to the effects of atmospheric evolution, seasonal changes, and endogenic processes. We have studied the evolution of Titan's polar region through a combination of analysis of imaging, elevation data, and geomorphic mapping, spatially explicit simulations of landform evolution, and quantitative comparison of the simulated landscapes with corresponding Titan morphology. We have quantitatively evaluated alternate scenarios for the landform evolution of Titan's polar terrain. The investigations have been guided by recent geomorphic mapping and topographic characterization of the polar regions that are used to frame hypotheses of process interactions, which have been evaluated using simulation modeling. Topographic information about Titan's polar region is be based on SAR-Topography and altimetry archived on PDS, SAR-based stereo radar-grammetry, radar-sounding lake depth measurements, and superposition relationships between geomorphologic map units, which we will use to create a generalized topographic map.

  13. Graphics of polar figure

    International Nuclear Information System (INIS)

    Macias B, L.R.

    1991-11-01

    The objective of this work, is that starting from a data file coming from a spectra that has been softened, and of the one that have been generated its coordinates to project it in stereographic form, to create the corresponding polar figure making use of the Cyber computer of the ININ by means of the GRAPHOS package. This work only requires a Beta, Fi and Intensity (I) enter data file. It starts of the existence of a softened spectra of which have been generated already with these data, making use of some language that in this case was FORTRAN for the Cyber computer, a program is generated supported in the Graphos package that allows starting of a reading of the Beta, Fi, I file, to generate the points in a stereographic projection and that it culminates with the graph of the corresponding polar figure. The program will request the pertinent information that is wanted to capture in the polar figure just as: date, name of the enter file, indexes of the polar figure, number of levels, radio of the stereographic projection (cms.), crystalline system to which belongs the sample, name the neuter graph file by create and to add the own general data. (Author)

  14. A systematic literature review of the effectiveness of non-pharmacological interventions to prevent wandering in dementia and evaluation of the ethical implications and acceptability of their use.

    Science.gov (United States)

    Robinson, L; Hutchings, D; Corner, L; Beyer, F; Dickinson, H; Vanoli, A; Finch, T; Hughes, J; Ballard, C; May, C; Bond, J

    2006-08-01

    To determine the effectiveness and cost-effectiveness of non-pharmacological interventions (excluding subjective barriers) in the prevention of wandering in people with dementia, in comparison with usual care, and to evaluate through the review and a qualitative study the acceptability to stakeholders of such interventions and identify ethical issues associated with their use. Major electronic databases were searched up until 31 March 2005. Specialists in the field. Selected studies were assessed and analysed. The results of two of the efficacy studies that used similar interventions, designs and outcome measures were pooled in a meta-analysis; results for other studies which reported standard deviations were presented in a forest plot. Owing to a lack of cost-effectiveness data, a modelling exercise could not be performed. Four focus groups were carried out with relevant stakeholders (n = 19) including people with dementia and formal and lay carers to explore ethical and acceptability issues in greater depth. Transcripts were coded independently by two reviewers to develop a coding frame. Analysis was via a thematic framework approach. Ten studies met the inclusion criteria (multi-sensory environment, three; music therapy, one; exercise, one; special care units, two; aromatherapy, two; behavioural intervention, one). There was no robust evidence to recommend any non-pharmacological intervention to reduce wandering in dementia. There was some evidence, albeit of poor quality, for the effectiveness of exercise and multi-sensory environment. There were no relevant studies to determine the cost-effectiveness of the interventions. Findings from the narrative review and focus groups on acceptability and ethical issues were comparable. Exercise and distraction therapies were the most acceptable interventions and raised no ethical concerns. All other interventions were considered acceptable except for physical restraints, which were considered unacceptable. Considerable

  15. Current path in light emitting diodes based on nanowire ensembles

    International Nuclear Information System (INIS)

    Limbach, F; Hauswald, C; Lähnemann, J; Wölz, M; Brandt, O; Trampert, A; Hanke, M; Jahn, U; Calarco, R; Geelhaar, L; Riechert, H

    2012-01-01

    Light emitting diodes (LEDs) have been fabricated using ensembles of free-standing (In, Ga)N/GaN nanowires (NWs) grown on Si substrates in the self-induced growth mode by molecular beam epitaxy. Electron-beam-induced current analysis, cathodoluminescence as well as biased μ-photoluminescence spectroscopy, transmission electron microscopy, and electrical measurements indicate that the electroluminescence of such LEDs is governed by the differences in the individual current densities of the single-NW LEDs operated in parallel, i.e. by the inhomogeneity of the current path in the ensemble LED. In addition, the optoelectronic characterization leads to the conclusion that these NWs exhibit N-polarity and that the (In, Ga)N quantum well states in the NWs are subject to a non-vanishing quantum confined Stark effect. (paper)

  16. Who Is Responsible? A Man With Dementia Wanders From Home, Is Hit by a Train, and Dies.

    Science.gov (United States)

    Young, Yuchi; Papenkov, Maksim; Nakashima, Taeko

    2018-03-27

    The impact of dementia and Alzheimer's disease extends far beyond the healthcare needs of the person with dementia. As the disease progresses, individuals with dementia often require ongoing formal or informal care for their basic daily routine because of behavior changes and continuing loss of cognitive function. Most of the care for people with dementia takes place at home, and the unpaid, informal caregivers are often spouses or other relatives. Providing long-term informal care at home for someone with dementia is psychologically, physically, and financially draining. The tragedy described in this case elucidates the far-reaching societal impact of dementia care and the implicit health policy considerations. In 2007, a 91-year-old Japanese man with dementia was in the care of his wife when he wandered from home, was hit by a train, and died, immediately affecting the Central Japan Railway Company operations and, subsequently, legal practice as well as Japanese elder care policy. The railway sued the man's wife and son for negligence and lost revenue, winning both trials at the local and district courts. This ruling shocked families and caregivers in Japan, where care for elderly parents traditionally falls on the oldest son, and brought attention to the complex issues related to dementia care. A decade later, we revisit this case to provoke a renewed dialogue about the matrix of responsibilities and liabilities associated with caregiving; to illuminate the unmet needs of the person with dementia, as well as his or her informal caregivers; and the financial implications related to long-term care policy. We close with 2 practical suggestions which preserve the dignity of the individual and provide reassurance for caregivers. Copyright © 2018 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

  17. Characterizing the velocity of a wandering black hole and properties of the surrounding medium using convolutional neural networks

    Science.gov (United States)

    González, J. A.; Guzmán, F. S.

    2018-03-01

    We present a method for estimating the velocity of a wandering black hole and the equation of state for the gas around it based on a catalog of numerical simulations. The method uses machine-learning methods based on convolutional neural networks applied to the classification of images resulting from numerical simulations. Specifically we focus on the supersonic velocity regime and choose the direction of the black hole to be parallel to its spin. We build a catalog of 900 simulations by numerically solving Euler's equations onto the fixed space-time background of a black hole, for two parameters: the adiabatic index Γ with values in the range [1.1, 5 /3 ], and the asymptotic relative velocity of the black hole with respect to the surroundings v∞, with values within [0.2 ,0.8 ]c . For each simulation we produce a 2D image of the gas density once the process of accretion has approached a stationary regime. The results obtained show that the implemented convolutional neural networks are able to correctly classify the adiabatic index 87.78% of the time within an uncertainty of ±0.0284 , while the prediction of the velocity is correct 96.67% of the time within an uncertainty of ±0.03 c . We expect that this combination of a massive number of numerical simulations and machine-learning methods will help us analyze more complicated scenarios related to future high-resolution observations of black holes, like those from the Event Horizon Telescope.

  18. Characteristics of volume polarization holography with linear polarization light

    Science.gov (United States)

    Zang, Jinliang; Wu, An'an; Liu, Ying; Wang, Jue; Lin, Xiao; Tan, Xiaodi; Shimura, Tsutomu; Kuroda, Kazuo

    2015-10-01

    Volume polarization holographic recording in phenanthrenequinone-doped poly(methyl methacrylate) (PQ-PMMA) photopolymer with linear polarized light is obtained. The characteristics of the volume polarization hologram are experimentally investigated. It is found that beyond the paraxial approximation the polarization states of the holographic reconstruction light are generally different from the signal light. Based on vector wave theoretical analyses and material properties, the special exposure condition for correctly holographic reconstruction is obtained and experimentally demonstrated.

  19. l-Theanine and caffeine improve target-specific attention to visual stimuli by decreasing mind wandering: a human functional magnetic resonance imaging study.

    Science.gov (United States)

    Kahathuduwa, Chanaka N; Dhanasekara, Chathurika S; Chin, Shao-Hua; Davis, Tyler; Weerasinghe, Vajira S; Dassanayake, Tharaka L; Binks, Martin

    2018-01-01

    Oral intake of l-theanine and caffeine supplements is known to be associated with faster stimulus discrimination, possibly via improving attention to stimuli. We hypothesized that l-theanine and caffeine may be bringing about this beneficial effect by increasing attention-related neural resource allocation to target stimuli and decreasing deviation of neural resources to distractors. We used functional magnetic resonance imaging (fMRI) to test this hypothesis. Solutions of 200mg of l-theanine, 160mg of caffeine, their combination, or the vehicle (distilled water; placebo) were administered in a randomized 4-way crossover design to 9 healthy adult men. Sixty minutes after administration, a 20-minute fMRI scan was performed while the subjects performed a visual color stimulus discrimination task. l-Theanine and l-theanine-caffeine combination resulted in faster responses to targets compared with placebo (∆=27.8milliseconds, P=.018 and ∆=26.7milliseconds, P=.037, respectively). l-Theanine was associated with decreased fMRI responses to distractor stimuli in brain regions that regulate visual attention, suggesting that l-theanine may be decreasing neural resource allocation to process distractors, thus allowing to attend to targets more efficiently. l-Theanine-caffeine combination was associated with decreased fMRI responses to target stimuli as compared with distractors in several brain regions that typically show increased activation during mind wandering. Factorial analysis suggested that l-theanine and caffeine seem to have a synergistic action in decreasing mind wandering. Therefore, our hypothesis is that l-theanine and caffeine may be decreasing deviation of attention to distractors (including mind wandering); thus, enhancing attention to target stimuli was confirmed. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Coupling channel evolution monitoring and RFID tracking in a large, wandering, gravel-bed river: Insights into sediment routing on geomorphic continuity through a riffle-pool sequence

    Science.gov (United States)

    Chapuis, Margot; Dufour, Simon; Provansal, Mireille; Couvert, Bernard; de Linares, Matthieu

    2015-02-01

    Bedload transport and bedform mobility in large gravel-bed rivers are not easily monitored, especially during floods. Large reaches present difficulties in bed access during flows for flow measurements. Because of these logistical issues, the current knowledge about bedload transport processes and bedform mobility lacks field-based information, while this missing information would precisely match river management needs. The lack of information linking channel evolution and particle displacements is even more striking in wandering reaches. The Durance River is a large, wandering, gravel-bed river (catchment area: 14,280 km2; mean width: 240 m), located in the southern French Alps and highly impacted by flow diversion and gravel mining. In order to improve current understanding of the link between sediment transport processes and river bed morphodynamics, we set up a sediment particle survey in the channel using Radio Frequency Identification (RFID) tracking and topographic surveys (GPS RTK and scour chains) for a 4-year recurrence interval flood. By combining topographic changes before and after a flood, intraflood erosion/deposition patterns from scour chains, differential routing of tracer particles, and spatial distribution of bed shear stress through a complex reach, this paper aims to define the critical shear stress for significant sediment mobility in this setting. Gravel tracking highlights displacement patterns in agreement with bar downstream migration and transport of particles across the riffle within this single flood event. Because no velocity measurements were possible during flood, a TELEMAC three-dimensional model helped interpret particle displacements by estimating spatial distribution of shear stresses and flow directions at peak flow. Although RFID tracking in a large, wandering, gravel-bed river does have some technical limitations (burial, recovery process time-consuming), it provides useful information on sediment routing through a riffle

  1. Design of a full-dynamic-range balanced detection heterodyne gyroscope with common-path configuration.

    Science.gov (United States)

    Lin, Chu-En; Yu, Chih-Jen; Chen, Chii-Chang

    2013-04-22

    In this article, we propose an optical heterodyne common-path gyroscope which has common-path configuration and full-dynamic range. Different from traditional non-common-path optical heterodyne technique such as Mach-Zehnder or Michelson interferometers, we use a two-frequency laser light source (TFLS) which can generate two orthogonally polarized light with a beat frequency has a common-path configuration. By use of phase measurement, this optical heterodyne gyroscope not only has the capability to overcome the drawback of the traditional interferometric fiber optic gyro: lack for full-dynamic range, but also eliminate the total polarization rotation caused by SMFs. Moreover, we also demonstrate the potential of miniaturizing this gyroscope as a chip device. Theoretically, if we assume that the wavelength of the laser light is 1550nm, the SMFs are 250m in length, and the radius of the fiber ring is 3.5cm, the bias stability is 0.872 deg/hr.

  2. Experiments with Fermilab polarized proton and polarized antiproton beams

    International Nuclear Information System (INIS)

    Yokosawa, A.

    1990-01-01

    We summarize activities concerning the Fermilab polarized beams. They include a brief description of the polarized-beam facility, measurements of beam polarization by polarimeters, asymmetry measurements in the π degree production at high p perpendicular and in the Λ (Σ degree), π ± , π degree production at large x F , and Δσ L (pp, bar pp) measurements. 18 refs

  3. NUCLEON POLARIZATION IN 3-BODY MODELS OF POLARIZED LI-6

    NARCIS (Netherlands)

    SCHELLINGERHOUT, NW; KOK, LP; COON, SA; ADAM, RM

    1993-01-01

    Just as He-3 --> can be approximately characterized as a polarized neutron target, polarized Li-6D has been advocated as a good isoscalar nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ''alpha + deuteron'' picture of Li-6,

  4. Gerbertian paths for the Jubilee

    Science.gov (United States)

    Sigismondi, Costantino

    2015-04-01

    Gerbert before becoming Pope Sylvester II came several times in Rome, as reported in his Letters and in the biography of Richerus. Eight places in Rome can be connected with Gerbertian memories. 1. The Cathedral of St. John in the Lateran where the gravestone of his tumb is still preserved near the Holy Door; 2. the “Basilica Hierusalem” (Santa Croce) where Gerbert had the stroke on May 3rd 1003 which lead him to death on May 12th; 3. the Aventine hill, with the church of the Knights of Malta in the place where the palace of the Ottonian Emperors was located; 4. the church of St. Bartholomew in the Tiber Island built in 997 under Otto III; 5. the Obelisk of Augustus in Montecitorio to remember the relationship between Gerbert, Astronomy and numbers which led the birth of the legends on Gerbert magician; 6. St. Mary Major end of the procession of August 15, 1000; 7. St. Paul outside the walls with the iconography of the Popes and 8. St. Peter's tumb end of all Romaei pilgrimages. This Gerbertian path in Rome suggests one way to accomplish the pilgrimage suggested by Pope Francis in the Bulla Misericordiae Vultus (14) of indiction of the new Jubilee.

  5. Inked Careers: Tattooing Professional Paths

    Directory of Open Access Journals (Sweden)

    Gabriela DeLuca

    2016-12-01

    Full Text Available The concept of career has an interdisciplinary and historical constitution, which includes persons, groups, organizations and society. Given that, we aim to deepen the interactionist notion of career from the understanding of a deviant path, supported by a theory and a method appropriated to the cited call for interdisciplinary approaches. Dilemmas (Hughes, 1958 and conflicts (Hughes, 1937 emerged as important analytical categories. Although necessary, these two concepts were not sufficient to contemplate analyses in their entirety. For this reason we conceptualized a third possibility of controversy during a career: the inquiries. The study followed the Narrative method to analyze objective and subjective changes during a tattoo artist’s career through interviews and informal conversations carried out over 22 months. The discussion presents three main contributions. Theoretically, a new understanding of the concept of careers, linking past, present and future and the idea of non-linearity of experienced and envisioned careers. Methodologically, suggesting orientations for future career studies such as the use of turning points as a methodological tool and the investigation of deviant fields. Finally, our defense of the interactionist perspective as suitable for career studies, since it allows the investigation of deviant elements.

  6. Geomagnetic polarity transitions

    Science.gov (United States)

    Merrill, Ronald T.; McFadden, Phillip L.

    1999-05-01

    The top of Earth's liquid outer core is nearly 2900 km beneath Earth's surface, so we will never be able to observe it directly. This hot, dense, molten iron-rich body is continuously in motion and is the source of Earth's magnetic field. One of the most dynamic manifestations at Earth's surface of this fluid body is, perhaps, a reversal of the geomagnetic field. Unfortunately, the most recent polarity transition occurred at about 780 ka, so we have never observed a transition directly. It seems that a polarity transition spans many human lifetimes, so no human will ever witness the phenomenon in its entirety. Thus we are left with the tantalizing prospect that paleomagnetic records of polarity transitions may betray some of the secrets of the deep Earth. Certainly, if there are systematics in the reversal process and they can be documented, then this will reveal substantial information about the nature of the lowermost mantle and of the outer core. Despite their slowness on a human timescale, polarity transitions occur almost instantaneously on a geological timescale. This rapidity, together with limitations in the paleomagnetic recording process, prohibits a comprehensive description of any reversal transition both now and into the foreseeable future, which limits the questions that may at this stage be sensibly asked. The natural model for the geomagnetic field is a set of spherical harmonic components, and we are not able to obtain a reliable model for even the first few harmonic terms during a transition. Nevertheless, it is possible, in principle, to make statements about the harmonic character of a geomagnetic polarity transition without having a rigorous spherical harmonic description of one. For example, harmonic descriptions of recent geomagnetic polarity transitions that are purely zonal can be ruled out (a zonal harmonic does not change along a line of latitude). Gleaning information about transitions has proven to be difficult, but it does seem

  7. Path Player Games Analysis and Applications

    CERN Document Server

    Schwarze, Silvia

    2008-01-01

    A path player game is an innovative type of game which considers network flow problems from the viewpoint of network owners. This strategy enables modeling real-world problems and has many practical applications. This book presents an exposition of the theoretical foundations of the concept of a path player game

  8. A Random Walk on a Circular Path

    Science.gov (United States)

    Ching, W.-K.; Lee, M. S.

    2005-01-01

    This short note introduces an interesting random walk on a circular path with cards of numbers. By using high school probability theory, it is proved that under some assumptions on the number of cards, the probability that a walker will return to a fixed position will tend to one as the length of the circular path tends to infinity.

  9. Evaluation of Calcine Disposition Path Forward

    International Nuclear Information System (INIS)

    Birrer, S.A.; Heiser, M.B.

    2003-01-01

    This document describes an evaluation of the baseline and two alternative disposition paths for the final disposition of the calcine wastes stored at the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory. The pathways are evaluated against a prescribed set of criteria and a recommendation is made for the path forward

  10. Cooperative organic mine avoidance path planning

    Science.gov (United States)

    McCubbin, Christopher B.; Piatko, Christine D.; Peterson, Adam V.; Donnald, Creighton R.; Cohen, David

    2005-06-01

    The JHU/APL Path Planning team has developed path planning techniques to look for paths that balance the utility and risk associated with different routes through a minefield. Extending on previous years' efforts, we investigated real-world Naval mine avoidance requirements and developed a tactical decision aid (TDA) that satisfies those requirements. APL has developed new mine path planning techniques using graph based and genetic algorithms which quickly produce near-minimum risk paths for complicated fitness functions incorporating risk, path length, ship kinematics, and naval doctrine. The TDA user interface, a Java Swing application that obtains data via Corba interfaces to path planning databases, allows the operator to explore a fusion of historic and in situ mine field data, control the path planner, and display the planning results. To provide a context for the minefield data, the user interface also renders data from the Digital Nautical Chart database, a database created by the National Geospatial-Intelligence Agency containing charts of the world's ports and coastal regions. This TDA has been developed in conjunction with the COMID (Cooperative Organic Mine Defense) system. This paper presents a description of the algorithms, architecture, and application produced.

  11. The Path of Carbon in Photosynthesis VI.

    Science.gov (United States)

    Calvin, M.

    1949-06-30

    This paper is a compilation of the essential results of our experimental work in the determination of the path of carbon in photosynthesis. There are discussions of the dark fixation of photosynthesis and methods of separation and identification including paper chromatography and radioautography. The definition of the path of carbon in photosynthesis by the distribution of radioactivity within the compounds is described.

  12. Development of a modelling learning path

    NARCIS (Netherlands)

    van Buuren, O.P.M.

    2014-01-01

    A learning path on computational modelling, integrated into the Dutch lower secondary physics curriculum has been developed and tested in school practice. The instructional materials that have been developed cover the first two years of this curriculum. In the learning path, modelling has been

  13. Joint modeling of constrained path enumeration and path choice behavior: a semi-compensatory approach

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2010-01-01

    A behavioural and a modelling framework are proposed for representing route choice from a path set that satisfies travellers’ spatiotemporal constraints. Within the proposed framework, travellers’ master sets are constructed by path generation, consideration sets are delimited according to spatio...... constraints are related to travellers’ socio-economic characteristics and that path choice is related to minimizing time and avoiding congestion....

  14. Polarized electron beams at SLAC

    International Nuclear Information System (INIS)

    Moffeit, K.C.

    1992-11-01

    SLAC has successfully accelerated high energy polarized electrons for the Stanford Linear Collider and fixed polarized nuclear target experiments. The polarized electron beams at SLAC use a gallium arsenide (GaAlAs for E-142) photon emission source to provide the beam of polarized electrons with polarization of approximately 28% (41% for E-142). While the beam emittance is reduced in the damping ring for SLC operation a system of bend magnets and superconducting solenoids preserve and orient the spin direction for maximum longitudinal polarization at the collision point. The electron polarization is monitored with a Compton scattering polarimeter, and was typically 22% at the e+e- collision point for the 1992 run. Improvements are discussed to increase the source polarization and to reduce the depolarization effects between the source and the collision point

  15. Analytical polarization calculations beyond SLIM

    International Nuclear Information System (INIS)

    Barber, D.P.

    1989-01-01

    A comparison is made between the theories of Bell and Leinaas and of Derbenev and Kondratenko for the spin polarization in electron storage rings. A calculation of polarization in HERA using the program SMILE of Mane is presented

  16. Optimization of educational paths for higher education

    Science.gov (United States)

    Tarasyev, Alexandr A.; Agarkov, Gavriil; Medvedev, Aleksandr

    2017-11-01

    In our research, we combine the theory of economic behavior and the methodology of increasing efficiency of the human capital to estimate the optimal educational paths. We provide an optimization model for higher education process to analyze possible educational paths for each rational individual. The preferences of each rational individual are compared to the best economically possible educational path. The main factor of the individual choice, which is formed by the formation of optimal educational path, deals with higher salaries level in the chosen economic sector after graduation. Another factor that influences on the economic profit is the reduction of educational costs or the possibility of the budget support for the student. The main outcome of this research consists in correction of the governmental policy of investment in human capital based on the results of educational paths optimal control.

  17. Proposal for a QND which-path measurement using photons

    International Nuclear Information System (INIS)

    Raymer, M.G.; Yang, S.

    1992-01-01

    A scheme is proposed for experimentally realizing the famous two-slit Gedaenken experiment using photons. As elegantly discussed for electrons by Feynman, a particle's quantum pathways interfere to produce fringes in the probability density for the particle to be found at a particle location. If the path taken by the particle is experimentally determined, the complementarity principle says that the fringes must disappear. To carry out this experiment with photons is difficult because normally the act of determining a photon's location destroys it. We propose to overcome this difficulty by putting a type-2 optical parametric amplifier (OPA) in each arm of a Mach-Zehnder interferometer, and observing fringes at the output. An OPA responds to an input photon by increasing its probability to produce a pair of photons with polarization orthogonal to the input, the detection of which allows partial inference about the path taken by the input photon without destroying it. Thus, the measurement is of the quantum nondemolition (QND) type

  18. On Determinants of Political Polarization

    OpenAIRE

    Grechyna, Daryna

    2015-01-01

    Political polarization has been shown to significantly influence a country's economic performance. However, little is known about the drivers of political polarization. In this article, we aim to identify the main determinants of political polarization using Bayesian Model Averaging to overcome the problem of model uncertainty. We find that the level of trust within a country and the degree of income inequality are the most robust determinants of political polarization.

  19. Investigation of the oxygen exchange mechanism on Pt|yttria stabilized zirconia at intermediate temperatures: Surface path versus bulk path

    International Nuclear Information System (INIS)

    Opitz, Alexander K.; Lutz, Alexander; Kubicek, Markus; Kubel, Frank; Hutter, Herbert; Fleig, Juergen

    2011-01-01

    Highlights: → Oxygen exchange kinetics of Pt on YSZ investigated by means of Pt model electrodes. → Two different geometry dependencies of the polarization resistance identified. → At higher temperatures the oxygen exchange reaction proceeds via a Pt surface path. → At lower temperatures a bulk path through the Pt thin film electrode is discussed. - Abstract: The oxygen exchange kinetics of platinum on yttria-stabilized zirconia (YSZ) was investigated by means of geometrically well-defined Pt microelectrodes. By variation of electrode size and temperature it was possible to separate two temperature regimes with different geometry dependencies of the polarization resistance. At higher temperatures (550-700 deg. C) an elementary step located close to the three phase boundary (TPB) with an activation energy of ∼1.6 eV was identified as rate limiting. At lower temperatures (300-400 deg. C) the rate limiting elementary step is related to the electrode area and exhibited a very low activation energy in the order of 0.2 eV. From these observations two parallel pathways for electrochemical oxygen exchange are concluded. The nature of these two elementary steps is discussed in terms of equivalent circuits. Two combinations of parallel rate limiting reaction steps are found to explain the observed geometry dependencies: (i) Diffusion through an impurity phase at the TPB in parallel to diffusion of oxygen through platinum - most likely along Pt grain boundaries - as area-related process. (ii) Co-limitation of oxygen diffusion along the Pt|YSZ interface and charge transfer at the interface with a short decay length of the corresponding transmission line (as TPB-related process) in parallel to oxygen diffusion through platinum.

  20. Path integration: effect of curved path complexity and sensory system on blindfolded walking.

    Science.gov (United States)

    Koutakis, Panagiotis; Mukherjee, Mukul; Vallabhajosula, Srikant; Blanke, Daniel J; Stergiou, Nicholas

    2013-02-01

    Path integration refers to the ability to integrate continuous information of the direction and distance traveled by the system relative to the origin. Previous studies have investigated path integration through blindfolded walking along simple paths such as straight line and triangles. However, limited knowledge exists regarding the role of path complexity in path integration. Moreover, little is known about how information from different sensory input systems (like vision and proprioception) contributes to accurate path integration. The purpose of the current study was to investigate how sensory information and curved path complexity affect path integration. Forty blindfolded participants had to accurately reproduce a curved path and return to the origin. They were divided into four groups that differed in the curved path, circle (simple) or figure-eight (complex), and received either visual (previously seen) or proprioceptive (previously guided) information about the path before they reproduced it. The dependent variables used were average trajectory error, walking speed, and distance traveled. The results indicated that (a) both groups that walked on a circular path and both groups that received visual information produced greater accuracy in reproducing the path. Moreover, the performance of the group that received proprioceptive information and later walked on a figure-eight path was less accurate than their corresponding circular group. The groups that had the visual information also walked faster compared to the group that had proprioceptive information. Results of the current study highlight the roles of different sensory inputs while performing blindfolded walking for path integration. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Polarized electrogowdy spacetimes censored

    Energy Technology Data Exchange (ETDEWEB)

    Nungesser, Ernesto, E-mail: ernesto.nungesser@aei.mpg.d [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany)

    2010-05-01

    A sketch of the proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  2. PEPPo: Using a Polarized Electron Beam to Produce Polarized Positrons

    Energy Technology Data Exchange (ETDEWEB)

    Adeyemi, Adeleke H. [Hampton Univ., Hampton, VA (United States); et al.

    2015-09-01

    Polarized positron beams have been identified as either an essential or a significant ingredient for the experimental program of both the present and next generation of lepton accelerators (JLab, Super KEK B, ILC, CLIC). An experiment demonstrating a new method for producing polarized positrons has been performed at the Continuous Electron Beam Accelerator Facility at Jefferson Lab. The PEPPo (Polarized Electrons for Polarized Positrons) concept relies on the production of polarized e⁻/e⁺ pairs from the bremsstrahlung radiation of a longitudinally polarized electron beam interacting within a high-Z conversion target. PEPPo demonstrated the effective transfer of spin-polarization of an 8.2 MeV/c polarized (P~85%) electron beam to positrons produced in varying thickness tungsten production targets, and collected and measured in the range of 3.1 to 6.2 MeV/c. In comparison to other methods this technique reveals a new pathway for producing either high-energy or thermal polarized positron beams using a relatively low polarized electron beam energy (~10MeV) .This presentation will describe the PEPPo concept, the motivations of the experiment and high positron polarization achieved.

  3. Polarization induced doped transistor

    Science.gov (United States)

    Xing, Huili; Jena, Debdeep; Nomoto, Kazuki; Song, Bo; Zhu, Mingda; Hu, Zongyang

    2016-06-07

    A nitride-based field effect transistor (FET) comprises a compositionally graded and polarization induced doped p-layer underlying at least one gate contact and a compositionally graded and doped n-channel underlying a source contact. The n-channel is converted from the p-layer to the n-channel by ion implantation, a buffer underlies the doped p-layer and the n-channel, and a drain underlies the buffer.

  4. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  5. Polarized advanced fuel reactors

    International Nuclear Information System (INIS)

    Kulsrud, R.M.

    1987-07-01

    The d- 3 He reaction has the same spin dependence as the d-t reaction. It produces no neutrons, so that if the d-d reactivity could be reduced, it would lead to a neutron-lean reactor. The current understanding of the possible suppression of the d-d reactivity by spin polarization is discussed. The question as to whether a suppression is possible is still unresolved. Other advanced fuel reactions are briefly discussed. 11 refs

  6. On polarization in biomembranes

    DEFF Research Database (Denmark)

    Zecchi, Karis Amata

    close to physiological conditions, making these effects biologically relevant. In this work, we consider the case of asymmetric membranes which can display spontaneous polarization in the absence of a field. Close to the phase transition, we find that the membrane displays piezoelectric, flexoelectric...... on different geometries point in the direction of a flexoelectric mechanism behind current rectification in lipid bilayers. Finally, we suggest that our updated equivalent circuit should be included in the interpretation of elctrophysiological data....

  7. Multifrequency Behaviour of Polars

    Directory of Open Access Journals (Sweden)

    K. Reinsch

    2015-02-01

    Full Text Available Cataclysmic variables emit over a wide range of the electromagnetic spectrum. In this paper I will review observations of polars in relevant passbands obtained during the last decade and will discuss their diagnostical potential to access the physics of the main components within the binary systems. This will include a discussion of intrinsic source variability and the quest for simultaneous multi-frequency observations.

  8. Polar Business Design

    Directory of Open Access Journals (Sweden)

    Sébastien Caisse

    2014-02-01

    Full Text Available Polar business design aims to enable entrepreneurs, managers, consultants, researchers, and business students to better tackle model-based analysis, creation, and transformation of businesses, ventures, and, more generically, collective endeavors of any size and purpose. It is based on a systems-thinking approach that builds on a few interrelated core concepts to create holistic visual frameworks. These core concepts act as poles linked by meaningful dyads, flows, and faces arranged in geometric shapes. The article presents two such polar frameworks as key findings in an ongoing analytic autoethnography: the three-pole Value−Activity−Stakeholder (VAS triquetra and the four-pole Offer−Creation−Character−Stakeholder (OCCS tetrahedron. The VAS triquetra is a more aggregated model of collective endeavors. The OCCS tetrahedron makes a trade-off between a steeper learning curve and deeper, richer representation potential. This article discusses how to use these two frameworks as well as their limits, and explores the potential that polar business design offers for future research.

  9. Multi-AGV path planning with double-path constraints by using an improved genetic algorithm.

    Science.gov (United States)

    Han, Zengliang; Wang, Dongqing; Liu, Feng; Zhao, Zhiyong

    2017-01-01

    This paper investigates an improved genetic algorithm on multiple automated guided vehicle (multi-AGV) path planning. The innovations embody in two aspects. First, three-exchange crossover heuristic operators are used to produce more optimal offsprings for getting more information than with the traditional two-exchange crossover heuristic operators in the improved genetic algorithm. Second, double-path constraints of both minimizing the total path distance of all AGVs and minimizing single path distances of each AGV are exerted, gaining the optimal shortest total path distance. The simulation results show that the total path distance of all AGVs and the longest single AGV path distance are shortened by using the improved genetic algorithm.

  10. Multi-AGV path planning with double-path constraints by using an improved genetic algorithm.

    Directory of Open Access Journals (Sweden)

    Zengliang Han

    Full Text Available This paper investigates an improved genetic algorithm on multiple automated guided vehicle (multi-AGV path planning. The innovations embody in two aspects. First, three-exchange crossover heuristic operators are used to produce more optimal offsprings for getting more information than with the traditional two-exchange crossover heuristic operators in the improved genetic algorithm. Second, double-path constraints of both minimizing the total path distance of all AGVs and minimizing single path distances of each AGV are exerted, gaining the optimal shortest total path distance. The simulation results show that the total path distance of all AGVs and the longest single AGV path distance are shortened by using the improved genetic algorithm.

  11. Theoretical study of built-in-polarization effect on relaxation time and ...

    Indian Academy of Sciences (India)

    It is found that combined relaxation time is enhanced due to built-in-polarization effect and makes phonon mean free path longer, which is required forhigher optical, electrical and thermal transport processes. The result can be used to determine the effect of built-inpolarization field on optical and thermal properties of Al x ...

  12. Theoretical study of built-in-polarization effect on relaxation time and ...

    Indian Academy of Sciences (India)

    tion. The combined relaxation time due to above-mentioned scattering mechanisms has also been computed as a function of phonon frequency for various Al compositions at room temperature. It is found that combined relaxation time is enhanced due to built-in-polarization effect and makes phonon mean free path longer, ...

  13. Dissociable cognitive mechanisms underlying human path integration.

    Science.gov (United States)

    Wiener, Jan M; Berthoz, Alain; Wolbers, Thomas

    2011-01-01

    Path integration is a fundamental mechanism of spatial navigation. In non-human species, it is assumed to be an online process in which a homing vector is updated continuously during an outward journey. In contrast, human path integration has been conceptualized as a configural process in which travelers store working memory representations of path segments, with the computation of a homing vector only occurring when required. To resolve this apparent discrepancy, we tested whether humans can employ different path integration strategies in the same task. Using a triangle completion paradigm, participants were instructed either to continuously update the start position during locomotion (continuous strategy) or to remember the shape of the outbound path and to calculate home vectors on basis of this representation (configural strategy). While overall homing accuracy was superior in the configural condition, participants were quicker to respond during continuous updating, strongly suggesting that homing vectors were computed online. Corroborating these findings, we observed reliable differences in head orientation during the outbound path: when participants applied the continuous updating strategy, the head deviated significantly from straight ahead in direction of the start place, which can be interpreted as a continuous motor expression of the homing vector. Head orientation-a novel online measure for path integration-can thus inform about the underlying updating mechanism already during locomotion. In addition to demonstrating that humans can employ different cognitive strategies during path integration, our two-systems view helps to resolve recent controversies regarding the role of the medial temporal lobe in human path integration.

  14. Quarkonium production in the LHC era: A polarized perspective

    Energy Technology Data Exchange (ETDEWEB)

    Faccioli, Pietro [Laboratório de Instrumentação e Física Experimental de Partículas (LIP), Lisbon (Portugal); Physics Department, Instituto Superior Técnico (IST), Lisbon (Portugal); Knünz, Valentin [Institute of High Energy Physics (HEPHY), Vienna (Austria); Lourenço, Carlos [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Seixas, João [Laboratório de Instrumentação e Física Experimental de Partículas (LIP), Lisbon (Portugal); Physics Department, Instituto Superior Técnico (IST), Lisbon (Portugal); Wöhri, Hermine K. [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

    2014-09-07

    Polarization measurements are usually considered as the most difficult challenge for the QCD description of quarkonium production. In fact, global data fits for the determination of the non-perturbative parameters of bound-state formation traditionally exclude polarization observables and use them as a posteriori verifications of the predictions, with perplexing results. With a change of perspective, we move polarization data to the centre of the study, advocating that they actually provide the strongest fundamental indications about the production mechanisms, even before we explicitly consider perturbative calculations. Considering ψ(2S) and ϒ(3S) measurements from LHC experiments and state-of-the-art next-to-leading order cross sections for the short-distance production of heavy quark–antiquark pairs of relevant colour and angular momentum configurations, we perform a search for a kinematic domain where quarkonium polarizations can be correctly reproduced together with the respective cross sections, by systematically scanning the phase space and accurately treating the experimental uncertainties. This strategy provides a straightforward solution to the “quarkonium polarization puzzle” and reassuring signs that the factorization of short- and long-distance effects works, at least in the high-transverse-momentum region, least affected by limitations in the current fixed-order calculations. The results expose unexpected hierarchies in the phenomenological long-distance parameters that open new paths towards the understanding of bound-state formation in QCD.

  15. Direct observation of hopping induced spin polarization current in oxygen deficient Co-doped ZnO by Andreev reflection technique

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Kung-Shang; Huang, Tzu-Yu; Dwivedi, G.D. [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Lin, Lu-Kuei; Lee, Shang-Fan [Taiwan Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Sun, Shih-Jye [Department of Applied Physics, National Kaohsiung University, Kaohsiung, Taiwan (China); Chou, Hsiung, E-mail: hchou@mail.nsysu.edu.tw [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China)

    2017-07-01

    Highlights: • Co-doped ZnO thin-films were grown with varying V{sub O} concentartion. • PCAR measurements were done to study the SPC. • High spin polarization was observed above a certain V{sub O} concentartion. • High V{sub O} samples provide a high density of completed percolation path. • This complete percolation path gives rise to high SPC. - Abstract: Oxygen vacancy induced ferromagnetic coupling in diluted magnetic oxide (DMO) semiconductors have been reported in several studies, but technologically more crucial spin-polarized current (SPC) is still under-developed in DMOs. Few studies have claimed that VRH mechanism can originate the SPC, but, how VRH mechanism associated with percolation path, is not clearly understood. We used Point-contact Andreev reflection (PCAR) technique to probe the SPC in Co-doped ZnO (CZO) films. Since the high resistance samples cause broadening in conductance(G)-voltage(V) curves, which may result in an unreliable evaluation of spin polarization, we include two extra parameters, (i) effective temperature and (ii) spreading resistance, for the simulation to avoid the uncertainty in extracting spin polarization. The effective G-V curves and higher spin polarization can be obtained above a certain oxygen vacancy concentration. The number of completed and fragmentary percolation paths is proportional to the concentration of oxygen vacancies. For low oxygen vacancy samples, the Pb-tip has a higher probability of covering fragmentary percolation paths than the complete ones, due to its small contact size. The completed paths may remain independent of one another and get polarized in different directions, resulting in lower spin-polarization value. High oxygen vacancy samples provide a high density of completed path, most of them link to one another by crossing over, and gives rise to high spin-polarization value.

  16. Path-Goal Theory of Leadership

    Science.gov (United States)

    1975-04-01

    Leadership and Turnover Among Managers ," Organization Behavior and Human Performance, 10(1973), pp. 184-200; R. J. House, "A Path-Goal Theory of...of Leadership ." 6R. J. House and G. Dessler, "Path-Goal Theory of Leadership " R. M. Stqg- dill. Managers , Employees, Organization (Ohio State...of Control." 23 R. J. House, "Notes on the Path-Goal Theory of Leadership " (University of Toronto, Faculty of Management Studies, May 1974). 24 R

  17. Integrated robust controller for vehicle path following

    International Nuclear Information System (INIS)

    Mashadi, Behrooz; Ahmadizadeh, Pouyan; Majidi, Majid; Mahmoodi-Kaleybar, Mehdi

    2015-01-01

    The design of an integrated 4WS+DYC control system to guide a vehicle on a desired path is presented. The lateral dynamics of the path follower vehicle is formulated by considering important parameters. To reduce the effect of uncertainties in vehicle parameters, a robust controller is designed based on a μ-synthesis approach. Numerical simulations are performed using a nonlinear vehicle model in MATLAB environment in order to investigate the effectiveness of the designed controller. Results of simulations show that the controller has a profound ability to making the vehicle track the desired path in the presence of uncertainties

  18. Path probabilities of continuous time random walks

    International Nuclear Information System (INIS)

    Eule, Stephan; Friedrich, Rudolf

    2014-01-01

    Employing the path integral formulation of a broad class of anomalous diffusion processes, we derive the exact relations for the path probability densities of these processes. In particular, we obtain a closed analytical solution for the path probability distribution of a Continuous Time Random Walk (CTRW) process. This solution is given in terms of its waiting time distribution and short time propagator of the corresponding random walk as a solution of a Dyson equation. Applying our analytical solution we derive generalized Feynman–Kac formulae. (paper)

  19. Integrated robust controller for vehicle path following

    Energy Technology Data Exchange (ETDEWEB)

    Mashadi, Behrooz; Ahmadizadeh, Pouyan, E-mail: p-ahmadizadeh@iust.ac.ir; Majidi, Majid, E-mail: m-majidi@iust.ac.ir [Iran University of Science and Technology, School of Automotive Engineering (Iran, Islamic Republic of); Mahmoodi-Kaleybar, Mehdi, E-mail: m-mahmoodi-k@iust.ac.ir [Iran University of Science and Technology, School of Mechanical Engineering (Iran, Islamic Republic of)

    2015-02-15

    The design of an integrated 4WS+DYC control system to guide a vehicle on a desired path is presented. The lateral dynamics of the path follower vehicle is formulated by considering important parameters. To reduce the effect of uncertainties in vehicle parameters, a robust controller is designed based on a μ-synthesis approach. Numerical simulations are performed using a nonlinear vehicle model in MATLAB environment in order to investigate the effectiveness of the designed controller. Results of simulations show that the controller has a profound ability to making the vehicle track the desired path in the presence of uncertainties.

  20. New framework for the Feynman path integral

    International Nuclear Information System (INIS)

    Shaharir, M.Z.

    1986-01-01

    The well-known Fourier integral solution of the free diffusion equation in an arbitrary Euclidean space is reduced to Feynmannian integrals using the method partly contained in the formulation of the Fresnelian integral. By replacing the standard Hilbert space underlying the present mathematical formulation of the Feynman path integral by a new Hilbert space, the space of classical paths on the tangent bundle to the Euclidean space (and more general to an arbitrary Riemannian manifold) equipped with a natural inner product, we show that our Feynmannian integral is in better agreement with the qualitative features of the original Feynman path integral than the previous formulations of the integral