385 research outputs found

    Randomly sampling thinking in the natural environment.

    Get PDF

    Pre-traumatic Factors of Career-Related PTSD: A Systematic Review of the Literature

    Full text link
    This paper examined and synthesized the (limited) available literature on the pre-traumatic predictors of PTSD, specifically targeting populations in which traumatic events are experienced frequently because of the requirements of their positions, i.e., firefighters, police, and military personnel. A total of 21 articles were included in the final literature review and were used to assess the current available knowledge of the pre-traumatic traits of career-related PTSD, and address potential gaps in the literature. The culmination of this research was used to create specific risk profiles for each of the high risk careers included in this review, firefighters, police, and military personnel. The research presented here discovered very little literature surrounding these high risk populations. Future research focusing on longitudinal prospective studies should be conducted on high risk populations so that training could better equip officers, firefighters, and military personnel to deal with PTEs, thus lowering the overall development of PTSD

    Exploring the Ecological Validity of Thinking on Demand: Neural Correlates of Elicited vs. Spontaneously Occurring Inner Speech

    Get PDF
    Psychology and cognitive neuroscience often use standardized tasks to elicit particular experiences. We explore whether elicited experiences are similar to spontaneous experiences. In an MRI scanner, five participants performed tasks designed to elicit inner speech (covertly repeating experimenter-supplied words), inner seeing, inner hearing, feeling, and sensing. Then, in their natural environments, participants were trained in four days of random-beep-triggered Descriptive Experience Sampling (DES). They subsequently returned to the scanner for nine 25-min resting-state sessions; during each they received four DES beeps and described those moments (9 × 4 = 36 moments per participant) of spontaneously occurring experience. Enough of those moments included spontaneous inner speech to allow us to compare brain activation during spontaneous inner speech with what we had found in task-elicited inner speech. ROI analysis was used to compare activation in two relevant areas (Heschl’s gyrus and left inferior frontal gyrus). Task-elicited inner speech was associated with decreased activation in Heschl’s gyrus and increased activation in left inferior frontal gyrus. However, spontaneous inner speech had the opposite effect in Heschl’s gyrus and no significant effect in left inferior frontal gyrus. This study demonstrates how spontaneous phenomena can be investigated in MRI and calls into question the assumption that task-created phenomena are often neurophysiologically and psychologically similar to spontaneously occurring phenomena

    Estimating Electric Fields from Vector Magnetogram Sequences

    Full text link
    Determining the electric field (E-field) distribution on the Sun's photosphere is essential for quantitative studies of how energy flows from the Sun's photosphere, through the corona, and into the heliosphere. This E-field also provides valuable input for data-driven models of the solar atmosphere and the Sun-Earth system. We show how Faraday's Law can be used with observed vector magnetogram time series to estimate the photospheric E-field, an ill-posed inversion problem. Our method uses a "poloidal-toroidal decomposition" (PTD) of the time derivative of the vector magnetic field. The PTD solutions are not unique; the gradient of a scalar potential can be added to the PTD E-field without affecting consistency with Faraday's Law. We present an iterative technique to determine a potential function consistent with ideal MHD evolution; but this E-field is also not a unique solution to Faraday's Law. Finally, we explore a variational approach that minimizes an energy functional to determine a unique E-field, similar to Longcope's "Minimum Energy Fit". The PTD technique, the iterative technique, and the variational technique are used to estimate E-fields from a pair of synthetic vector magnetograms taken from an MHD simulation; and these E-fields are compared with the simulation's known electric fields. These three techniques are then applied to a pair of vector magnetograms of solar active region NOAA AR8210, to demonstrate the methods with real data.Comment: 41 pages, 10 figure

    An Interface Region Imaging Spectrograph first view on Solar Spicules

    Full text link
    Solar spicules have eluded modelers and observers for decades. Since the discovery of the more energetic type II, spicules have become a heated topic but their contribution to the energy balance of the low solar atmosphere remains unknown. Here we give a first glimpse of what quiet Sun spicules look like when observed with NASA's recently launched Interface Region Imaging Spectrograph (IRIS). Using IRIS spectra and filtergrams that sample the chromosphere and transition region we compare the properties and evolution of spicules as observed in a coordinated campaign with Hinode and the Atmospheric Imaging Assembly. Our IRIS observations allow us to follow the thermal evolution of type II spicules and finally confirm that the fading of Ca II H spicules appears to be caused by rapid heating to higher temperatures. The IRIS spicules do not fade but continue evolving, reaching higher and falling back down after 500-800 s. Ca II H type II spicules are thus the initial stages of violent and hotter events that mostly remain invisible in Ca II H filtergrams. These events have very different properties from type I spicules, which show lower velocities and no fading from chromospheric passbands. The IRIS spectra of spicules show the same signature as their proposed disk counterparts, reinforcing earlier work. Spectroheliograms from spectral rasters also confirm that quiet Sun spicules originate in bushes from the magnetic network. Our results suggest that type II spicules are indeed the site of vigorous heating (to at least transition region temperatures) along extensive parts of the upward moving spicular plasma.Comment: 6 pages, 4 figures, accepted for publication in ApJ Letters. For associated movies, see http://folk.uio.no/tiago/iris_spic

    Convective quenching of stellar pulsations

    Full text link
    Context: we study the convection-pulsation coupling that occurs in cold Cepheids close to the red edge of the classical instability strip. In these stars, the surface convective zone is supposed to stabilise the radial oscillations excited by the kappa-mechanism. Aims: we study the influence of the convective motions onto the amplitude and the nonlinear saturation of acoustic modes excited by kappa-mechanism. We are interested in determining the physical conditions needed to lead to a quenching of oscillations by convection. Methods: we compute two-dimensional nonlinear simulations (DNS) of the convection-pulsation coupling, in which the oscillations are sustained by a continuous physical process: the kappa-mechanism. Thanks to both a frequential analysis and a projection of the physical fields onto an acoustic subspace, we study how the convective motions affect the unstable radial oscillations. Results: depending on the initial physical conditions, two main behaviours are obtained: (i) either the unstable fundamental acoustic mode has a large amplitude, carries the bulk of the kinetic energy and shows a nonlinear saturation similar to the purely radiative case; (ii) or the convective motions affect significantly the mode amplitude that remains very weak. In this second case, convection is quenching the acoustic oscillations. We interpret these discrepancies in terms of the difference in density contrast: larger stratification leads to smaller convective plumes that do not affect much the purely radial modes, while large-scale vortices may quench the oscillations.Comment: 15 pages, 17 figures, 3 tables, accepted for publication in A&

    GODAE systems in operation

    Get PDF
    During the last 15 years, operational oceanography systems have been developed in several countries around the world. These developments have been fostered primarily by the Global Ocean Data Assimilation Experiment (GODAE), which coordinated these activities, encouraged partnerships, and facilitated constructive competition. This multinational coordination has been very beneficial for the development of operational oceanography. Today, several systems provide routine, real-time ocean analysis, forecast, and reanalysis products. These systems are based on (1) state-of-the-art Ocean General Circulation Model (OGCM) configurations, either global or regional (basin-scale), with resolutions that range from coarse to eddy-resolving, and (2) data assimilation techniques ranging from analysis correction to advanced three- or four-dimensional variational schemes. These systems assimilate altimeter sea level anomalies, sea surface temperature data, and in situ profiles of temperature and salinity, including Argo data. Some systems have implemented downscaling capacities, which consist of embedding higher-resolution local systems in global and basin-scale models (through open boundary exchange of data), especially in coastal regions, where small scale-phenomena are important, and also increasing the spatial resolution for these regional/coastal systems to be able to resolve smaller scales (so-called downscaling). Others have implemented coupling with the atmosphere and/or sea ice. This paper provides a short review of these operational GODAE systems.Published76-914.6. Oceanografia operativa per la valutazione dei rischi in aree marineN/A or not JCRope

    Detection of supersonic downflows and associated heating events in the transition region above sunspots

    Get PDF
    IRIS data allow us to study the solar transition region (TR) with an unprecedented spatial resolution of 0.33 arcsec. On 2013 August 30, we observed bursts of high Doppler shifts suggesting strong supersonic downflows of up to 200 km/s and weaker, slightly slower upflows in the spectral lines Mg II h and k, C II 1336 \AA, Si IV 1394 \AA, and 1403 \AA, that are correlated with brightenings in the slitjaw images (SJIs). The bursty behavior lasts throughout the 2 hr observation, with average burst durations of about 20 s. The locations of these short-lived events appear to be the umbral and penumbral footpoints of EUV loops. Fast apparent downflows are observed along these loops in the SJIs and in AIA, suggesting that the loops are thermally unstable. We interpret the observations as cool material falling from coronal heights, and especially coronal rain produced along the thermally unstable loops, which leads to an increase of intensity at the loop footpoints, probably indicating an increase of density and temperature in the TR. The rain speeds are on the higher end of previously reported speeds for this phenomenon, and possibly higher than the free-fall velocity along the loops. On other observing days, similar bright dots are sometimes aligned into ribbons, resembling small flare ribbons. These observations provide a first insight into small-scale heating events in sunspots in the TR.Comment: accepted by ApJ
    • …
    corecore