186 research outputs found

    The Relation of After-image Duration to Certain Aspects of Personality

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    Ph.D. University of Kansas, Psychology 1952In this study, consequently, to explore the relationship of personality characteristics to after-image duration, the Minnesota Multiphasic Personality Inventory (19) was used. In addition, the Otis Self Administering Intelligence Test, Higher Form, was used to provide a check on previous reports (42,49) that intelligence, too, is an important factor in after-image perception. To explore possible relationships between after-image duration and visual discrimination tasks flicker-fusion thresholds and brightness thresholds for the appearance and disappearance of the negative after-image were determined

    A modeling study on the response of Chesapeake Bay to hurricane events of Floyd and Isabel

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    The response of Chesapeake Bay to forcing from two hurricanes is investigated using an unstructured-grid three-dimensional hydrodynamic model SELFE. The model domain includes Chesapeake Bay, its tributaries, and the extended continental shelf in the mid-Atlantic Bight. The hurricanes chosen for the study are Hurricane Floyd (1999) and Hurricane Isabel (2003), both of which made landfall within 100 km of the mouth of the Bay. The model results agree reasonably well with field observations of water level, velocity, and salinity. From the Bay\u27s water level response to the hurricanes, it was found that the storm surge in the Bay has two distinct stages: an initial stage set up by the remote winds and the second stage - a primary surge induced by the local winds. For the initial stage, the rising of the coastal sea level was setup by the remote wind of both hurricanes similarly, but for the second stage, the responses to the two hurricanes\u27 local winds are significantly different. Hurricane Floyd was followed by down-Bay winds that canceled the initial setup and caused a set-down from the upper Bay. Hurricane Isabel, on the other hand, was followed by up-Bay winds, which reinforced the initial setup and continued to rise up against the head of the Bay. From the perspective of volume and salt fluxes, it is evident that an oceanic saltwater influx is pushed into the Bay from the continental shelf by the remote wind fields in the initial stages of the storm surge for both Floyd and Isabel. In the second stage after the hurricane made landfall, the Bay\u27s local wind plays a key role in modulating the salinity and velocity fields through vertical mixing and longitudinal salt transport. Controlled numerical experiments are conducted in order to identify and differentiate the roles played by the local wind in stratified and destratified conditions. Down-estuary local wind stress (of Hurricane Floyd-type) tends to enhance stratification under moderate winds, but exhibits an increasing-then-decreasing stage when the wind stress increases. The up-estuary local wind stress (of Hurricane Isabel-type) tends to penetrate deeper into the water column, which reduces stratification by reversing gravitational circulation. To characterize mixing conditions in the estuary, a modified horizontal Richardson number that incorporates wind stress, wind direction, horizontal salinity gradient, and vertical eddy viscosity is used for both hurricanes. Finally, the direct precipitation of rainfall into the Bay during Hurricane Floyd appears to create not only a thin surface layer of low salinity but also a seaward barotropic pressure gradient that affects the subsequent redistribution of salinity after the storm. (C) 2012 Elsevier Ltd. All rights reserved

    A 3D unstructured-grid model for Chesapeake Bay: importance of bathymetry

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    We extend the 3D unstructured-grid model previously developed for the Upper Chesapeake Bay to cover the entire Bay and its adjacent shelf, and assess its skill in simulating saltwater intrusion and the coastal plume. Recently developed techniques, including a flexible vertical grid system and a 2nd-order, monotone and implicit transport solver are critical in successfully capturing the baroclinic responses. Most importantly, good accuracy is achieved through an accurate representation of the underlying bathymetry, without any smoothing. The model in general exhibits a good skill for all hydrodynamic variables: the averaged root-mean-square errors (RMSE‟s) in the Bay are 9 cm for sub-tidal frequency elevation, 17 cm/s for 3D velocity time series, 1.5 PSU and 1.9 PSU for surface and bottom salinity respectively, 1.1 °C and 1.6 °C for surface and bottom temperature respectively. On the shelf, the average RMSE for the surface temperature is 1.4 °C. We highlight, through results from sensitivity tests, the central role played by bathymetry in this estuarine system and the detrimental effects, from a common class of bathymetry smoothers, on volumetric and tracer fluxes as well as key processes such as the channel-shoal contrast in the estuary and plume propagation in the coast. Associated Data is available: https://doi.org/10.21220/V5HK5

    Gravitational radiation from gamma-ray bursts as observational opportunities for LIGO and VIRGO

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    Gamma-ray bursts are believed to originate in core-collapse of massive stars. This produces an active nucleus containing a rapidly rotating Kerr black hole surrounded by a uniformly magnetized torus represented by two counter-oriented current rings. We quantify black hole spin-interactions with the torus and charged particles along open magnetic flux-tubes subtended by the event horizon. A major output of Egw=4e53 erg is radiated in gravitational waves of frequency fgw=500 Hz by a quadrupole mass-moment in the torus. Consistent with GRB-SNe, we find (i) Ts=90s (tens of s, Kouveliotou et al. 1993), (ii) aspherical SNe of kinetic energy Esn=2e51 erg (2e51 erg in SN1998bw, Hoeflich et al. 1999) and (iii) GRB-energies Egamma=2e50 erg (3e50erg in Frail et al. 2001). GRB-SNe occur perhaps about once a year within D=100Mpc. Correlating LIGO/Virgo detectors enables searches for nearby events and their spectral closure density 6e-9 around 250Hz in the stochastic background radiation in gravitational waves. At current sensitivity, LIGO-Hanford may place an upper bound around 150MSolar in GRB030329. Detection of Egw thus provides a method for identifying Kerr black holes by calorimetry.Comment: to appear in PRD, 49

    An Open Letter to Congressman Gingrich

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    We urge you to reconsider your proposal to amend the House Rules to require a three-fifths vote for enactment of laws that increase income taxes. This proposal violates the explicit intentions of the Framers. It is inconsistent with the Constitution\u27s language and structure. It departs sharply from traditional congressional practice. It may generate constitutional litigation that will encourage Supreme Court intervention in an area best left to responsible congressional decision. Unless the proposal is withdrawn now, it will serve as an unfortunate precedent for the proliferation of supermajority rules on a host of different subjects in the future. Over time, we will see the continuing erosion of our central constitutional commitments to majority rule and deliberative democracy

    D-cycloserine augmentation of exposure-based cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders: a systematic review and meta-analysis of individual participant data

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    Importance: Whether and under which conditions D-cycloserine (DCS) augments the effects of exposure-based cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders is unclear. Objective: To clarify whether DCS is superior to placebo in augmenting the effects of cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders and to evaluate whether antidepressants interact with DCS and the effect of potential moderating variables. Data Sources: PubMed, EMBASE, and PsycINFO were searched from inception to February 10, 2016. Reference lists of previous reviews and meta-analyses and reports of randomized clinical trials were also checked. Study Selection: Studies were eligible for inclusion if they were (1) double-blind randomized clinical trials of DCS as an augmentation strategy for exposure-based cognitive behavior therapy and (2) conducted in humans diagnosed as having specific phobia, social anxiety disorder, panic disorder with or without agoraphobia, obsessive-compulsive disorder, or posttraumatic stress disorder. Data Extraction and Synthesis: Raw data were obtained from the authors and quality controlled. Data were ranked to ensure a consistent metric across studies (score range, 0-100). We used a 3-level multilevel model nesting repeated measures of outcomes within participants, who were nested within studies. Results: Individual participant data were obtained for 21 of 22 eligible trials, representing 1047 of 1073 eligible participants. When controlling for antidepressant use, participants receiving DCS showed greater improvement from pretreatment to posttreatment (mean difference, -3.62; 95% CI, -0.81 to -6.43; P = .01; d = -0.25) but not from pretreatment to midtreatment (mean difference, -1.66; 95% CI, -4.92 to 1.60; P = .32; d = -0.14) or from pretreatment to follow-up (mean difference, -2.98, 95% CI, -5.99 to 0.03; P = .05; d = -0.19). Additional analyses showed that participants assigned to DCS were associated with lower symptom severity than those assigned to placebo at posttreatment and at follow-up. Antidepressants did not moderate the effects of DCS. None of the prespecified patient-level or study-level moderators was associated with outcomes. Conclusions and Relevance: D-cycloserine is associated with a small augmentation effect on exposure-based therapy. This effect is not moderated by the concurrent use of antidepressants. Further research is needed to identify patient and/or therapy characteristics associated with DCS response.2018-05-0
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