15,261 research outputs found

    Eye-controlled ''teletypewriter''

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    Oculometer provides dynamic measurement of subject's look direction, and its outputs can be used to generate visual display of his look pattern and/or to cause equipment operation associated with his lookpoint at given times. Measured eye-direction information could be used as control input at man/machine interface

    Apparent movement phenomena on CRT displays - Threshold determinations of apparent movements of pulsed light sources

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    Apparent movement phenomena on cathode ray tube displays - threshold determinations of apparent movements of pulsed light source

    Current and future graphics requirements for LaRC and proposed future graphics system

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    The findings of an investigation to assess the current and future graphics requirements of the LaRC researchers with respect to both hardware and software are presented. A graphics system designed to meet these requirements is proposed

    Collisions of boosted black holes: perturbation theory prediction of gravitational radiation

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    We consider general relativistic Cauchy data representing two nonspinning, equal-mass black holes boosted toward each other. When the black holes are close enough to each other and their momentum is sufficiently high, an encompassing apparent horizon is present so the system can be viewed as a single, perturbed black hole. We employ gauge-invariant perturbation theory, and integrate the Zerilli equation to analyze these time-asymmetric data sets and compute gravitational wave forms and emitted energies. When coupled with a simple Newtonian analysis of the infall trajectory, we find striking agreement between the perturbation calculation of emitted energies and the results of fully general relativistic numerical simulations of time-symmetric initial data.Comment: 5 pages (RevTex 3.0 with 3 uuencoded figures), CRSR-107

    Improving teleportation of continuous variables by local operations

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    We study a continuous-variable (CV) teleportation protocol based on a shared entangled state produced by the quantum-nondemolition (QND) interaction of two vacuum states. The scheme utilizes the QND interaction or an unbalanced beam splitter in the Bell measurement. It is shown that in the non-unity gain regime the signal transfer coefficient can be enhanced while the conditional variance product remains preserved by applying appropriate local squeezing operation on sender's part of the shared entangled state. In the unity gain regime it is demonstrated that the fidelity of teleportation can be increased with the help of the local squeezing operations on parts of the shared entangled state that convert effectively our scheme to the standard CV teleportation scheme. Further, it is proved analytically that such a choice of the local symplectic operations minimizes the noise by which the mean number of photons in the input state is increased during the teleportation. Finally, our analysis reveals that the local symplectic operation on sender's side can be integrated into the Bell measurement if the interaction constant of the interaction in the Bell measurement can be adjusted properly.Comment: 10 pages, 1 figure, discussion of the non-unity gain teleportation is adde

    The role of attitude, control and intention to explain fruit and vegetable intake among racial/ethnic minority women with low socioeconomic status

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    OBJECTIVE: Fruit and Vegetable (FV) intake-a modi able risk factor for chronic diseases-is lower among racial/ethnic minorities and low Socio- Economic Status (SES) groups when compared to other populations. The Theory of Planned Behavior (TPB) is one theoretical model studied to explain and in uence individual health behaviors, including FV intake, in middle class populations, but not exclusively in diverse, low SES groups. This cross-sectional study evaluated the utility of select TPB variables to explain intention to consume and intake of FV in this population. DESIGN: Demographics, BMI, select TPB variables, and FV intake were measured via survey. Bivariate analyses were conducted to explore relationships between variables. Hierarchical regression analyses were used to t two models: one to explain intention and one to explain behavior with regard to FV vegetable intake. RESULTS: Participants (n=114) age 25-69 years and were mostly African American/Black and Hispanic (21.9% and 73%, respectively). The TPB variable perceived behavioral control was the only signi cant predictor of intention to consume FV (OR=2.55, 95% CI OR: 1.23, 5.27), and with BMI, FV intake (R2=0.08; F [2,130] =5.72, p=0.0042). CONCLUSION: Perceived behavioral control and BMI are the most signi cant predictors of FV intake but explain only 8% of the variability in intake in our cohort. Our results support prior research which suggests an attenuation of the intention-behavior relationship by SES, and may question the utility of the TPB as it is currently operationalized as a foundational model for future health behavior change research and programs in low SES racial/ethnic minorities

    Pilot and feasibility test of an implementation intention intervention to improve fruit and vegetable intake among women with low socioeconomic status

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    Fruit and vegetable intake (FVI), a modifiable risk factor for chronic diseases, is lower in low socioeconomic status (SES) populations. Implementation intentions (a specific type of planning that extends the Theory of Planned Behavior) has been studied to improve FVI, but not exclusively with low SES groups. Using mixed methods, we evaluated the feasibility, acceptability, and preliminary efficacy of an implementation intention intervention (versus a general plan) to increase FVI in women with low SES. For the pilot randomized controlled trial, demographics, body mass index, attitude, perceived behavioral control, goal intention strength, and FVI were measured at baseline and FVI again 1-month following the intervention. Feasibility data were collected for recruitment, randomization, retention, and assessment procedures and compared to predetermined targets. Semi-structured interview data was analyzed for emergent themes regarding acceptability of the trial. Preliminary efficacy of the intervention to improve FVI was analyzed descriptively. Feasibility targets were met for randomization (100% vs. ≥80% target), retention (93.5% vs. ≥70% target) and the assessment metrics missing data points (2% vs. ≤10% target) and days from intervention to follow up (mean=69.2, sd=42.6 vs.days). Targets for recruitment were not met with the exception of participants giving informed consent (100% vs. ≥70% target). Participants described the intervention as enjoyable and reported behavioral constructs outside of those measured as important to improve FVI. Limited efficacy analysis suggested that both groups increased their FVI (experimental: +0.17 servings per day, 95% CI: -0.85, 1.20; control: +0.50 servings per day, 95% CI: -0.56, 1.58). Further research which examines interventions based upon behavior change models to improve dietary health behaviors in marginalized groups is needed

    Statistical mechanics of damage phenomena

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    This paper applies the formalism of classical, Gibbs-Boltzmann statistical mechanics to the phenomenon of non-thermal damage. As an example, a non-thermal fiber-bundle model with the global uniform (meanfield) load sharing is considered. Stochastic topological behavior in the system is described in terms of an effective temperature parameter thermalizing the system. An equation of state and a topological analog of the energy-balance equation are obtained. The formalism of the free energy potential is developed, and the nature of the first order phase transition and spinodal is demonstrated.Comment: Critical point appeared to be a spinodal poin
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