624 research outputs found

    Analysis of heating rates and forces on bodies subject to rocket exhaust plume impingement

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    Computer programs and engineering methods for calculating heating rates and forces in jet plume impingement problem

    The Effects of Role Stress Elements on Primary School Counselor\u27s Perceived General Self-Efficacy

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    The authors examined the predictive relationship between role stress elements (role ambiguity and role conflict) and the perceived general self-efficacy of primary school counselors’ ability to effectively implement a comprehensive counseling program. A standard multiple regression technique was computed to test whether a relationship exists between role stress elements (role conflict and role ambiguity) of primary school counselors and their perceived general self-efficacy scores. The predictor variable role ambiguity and role conflict accounted for 8.6% (Adjusted = 6.5%) of the variance in the criterion variable perceived general self-efficacy scores. The results revealed a linear relationship between role stress elements and the general perceived self-efficacy scores of primary school counselors. Role ambiguity, ambiguous and unclear expectations not aligned with the American School Counseling Association (ASCA) National Model, were identified as the independent predictor of primary school counselors\u27 general self-efficacy scores. Findings support the importance of alignment between the American School Counselor Association (ASCA) National Model and assigned roles and responsibilities of primary school counselors to increase perceived self-efficacy and diminish the experiences of role stress

    Resonance between Noise and Delay

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    We propose here a stochastic binary element whose transition rate depends on its state at a fixed interval in the past. With this delayed stochastic transition this is one of the simplest dynamical models under the influence of ``noise'' and ``delay''. We demonstrate numerically and analytically that we can observe resonant phenomena between the oscillatory behavior due to noise and that due to delay.Comment: 4 pages, 5 figures, submitted to Phys.Rev.Lett Expanded and Added Reference

    Creating massive entanglement of Bose condensed atoms

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    We propose a direct, coherent coupling scheme that can create massively entangled states of Bose-Einstein condensed atoms. Our idea is based on an effective interaction between two atoms from coherent Raman processes through a (two atom) molecular intermediate state. We compare our scheme with other recent proposals for generation of massive entanglement of Bose condensed atoms.Comment: 5 pages, 3 figures; Updated figure 3(a), original was "noisy

    Natural images from the birthplace of the human eye

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    Here we introduce a database of calibrated natural images publicly available through an easy-to-use web interface. Using a Nikon D70 digital SLR camera, we acquired about 5000 six-megapixel images of Okavango Delta of Botswana, a tropical savanna habitat similar to where the human eye is thought to have evolved. Some sequences of images were captured unsystematically while following a baboon troop, while others were designed to vary a single parameter such as aperture, object distance, time of day or position on the horizon. Images are available in the raw RGB format and in grayscale. Images are also available in units relevant to the physiology of human cone photoreceptors, where pixel values represent the expected number of photoisomerizations per second for cones sensitive to long (L), medium (M) and short (S) wavelengths. This database is distributed under a Creative Commons Attribution-Noncommercial Unported license to facilitate research in computer vision, psychophysics of perception, and visual neuroscience.Comment: Submitted to PLoS ON

    Visible, EUV, and X-ray Spectroscopy at the NIST EBIT Facility

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    After a brief introduction to the NIST EBIT facility, we present the results of three different types of experiments that have been carried out there recently: EUV and visible spectroscopy in support of the microelectronics industry, laboratory astrophysics using an x-ray microcalorimeter, and charge exchange studies using extracted beams of highly charged ions.Comment: 10 page

    VERITAS and Multiwavelength Observations of the BL Lacertae Object 1ES 1741+196

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    We present results from multiwavelength observations of the BL Lacertae object 1ES 1741+196, including results in the very-high-energy γ\gamma-ray regime using the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The VERITAS time-averaged spectrum, measured above 180 GeV, is well-modelled by a power law with a spectral index of 2.7±0.7stat±0.2syst2.7\pm0.7_{\mathrm{stat}}\pm0.2_{\mathrm{syst}}. The integral flux above 180 GeV is (3.9±0.8stat±1.0syst)×108(3.9\pm0.8_{\mathrm{stat}}\pm1.0_{\mathrm{syst}})\times 10^{-8} m2^{-2} s1^{-1}, corresponding to 1.6% of the Crab Nebula flux on average. The multiwavelength spectral energy distribution of the source suggests that 1ES 1741+196 is an extreme-high-frequency-peaked BL Lacertae object. The observations analysed in this paper extend over a period of six years, during which time no strong flares were observed in any band. This analysis is therefore one of the few characterizations of a blazar in a non-flaring state.Comment: 8 pages, 5 figures. Accepted for publication in MNRA

    Investigating the TeV Morphology of MGRO J1908+06 with VERITAS

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    We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy (VHE) gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14 sigma) and measure a photon index of 2.20 +/- 0.10_stat +/- 0.20_sys. The TeV emission is extended, covering the region near PSR J1907+0602 and also extending towards SNR G40.5--0.5. When fitted with a 2-dimensional Gaussian, the intrinsic extension has a standard deviation of sigma_src = 0.44 +/- 0.02 degrees. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5--0.5, 0.33 degrees away.Comment: To appear in ApJ, 8 page
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