2,551 research outputs found

    It's About Cameras, and your Future, and your Life

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    The Effects of Prior Knowledge and Hyperlinks on Learning from a Decision Aid

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    The epistemology of post-implementation evaluation / 1574

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    Bibliography: p. [24-29]

    Decision table for classifying point sources based on FIRST and 2MASS databases

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    With the availability of multiwavelength, multiscale and multiepoch astronomical catalogues, the number of features to describe astronomical objects has increases. The better features we select to classify objects, the higher the classification accuracy is. In this paper, we have used data sets of stars and quasars from near infrared band and radio band. Then best-first search method was applied to select features. For the data with selected features, the algorithm of decision table was implemented. The classification accuracy is more than 95.9%. As a result, the feature selection method improves the effectiveness and efficiency of the classification method. Moreover the result shows that decision table is robust and effective for discrimination of celestial objects and used for preselecting quasar candidates for large survey projects.Comment: 10 pages. accepted by Advances in Space Researc

    Mechanical and hydrologic basis for the rapid motion of a large tidewater glacier 2. Interpretation

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    The data presented in part 1 of this paper (Meier et al., this issue) are here used to assess the role of water input/output, water storage, and basal water pressure in the rapid movement of Columbia Glacier, Alaska. Consistently high basal water pressures, mostly in the range from 300 kPa below to 100 kPa above the ice overburden pressure, are responsible in an overall way for the high glacier flow velocities (3.5–9 m d^−1), which are due mainly to rapid basal sliding caused by the high water pressure. Diurnal fluctuation in basal water pressure is accompanied by fluctuation in sliding velocity in what appears to be a direct causal relation at the upglacier observation site. The water pressure fluctuation tracks the time-integrated water input (less a steady withdrawal), as expected for the diurnally fluctuating storage of water in the glacier far from the terminus. At the downglacier site, the situation is more complex. Diurnal peaks in water level, which are directly related to intraglacial water storage as well as to basal water pressure, are shifted forward in time by 4 hours, probably as a result of the effect of diurnal fluctuation in water output from the glacier, which affects the local water storage fluctuations near the terminus. Because of the forward shift in the basal water pressure peaks, which at the downglacier site lead the velocity peaks by 6 hours, a mechanical connection between water pressure and sliding there would have to involve a 6-hour (quarter period) delay. However, the nearly identical nature of the diurnal fluctuations in velocity at the two sites argues for a single, consistent control mechanism at both sites. The velocity variations in nondiurnal “speed-up events” caused by extra input of water on the longer timescale of several days are only obscurely if at all correlated with variations in basal water pressure but correlate well with water storage in the glacier. It appears that small variations in water pressure (≤100 kPa) sufficient to produce the observed velocity variations (15–30%) are mostly masked by pressure fluctuations caused by spontaneous local reorganizations of the basal water conduit system on a spatial scale much smaller than the longitudinal coupling length over which basal water pressure is effectively averaged in determining the sliding velocity. At the achieved level of observation the clearest (though not complication free) control variable for the sliding velocity variations is basal water storage by cavitation at the glacier bed

    Need depriving effects of financial insecurity: Implications for well-being and financial behaviors

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    Evidence suggests that experiencing financial insecurity lowers well-being and increases problematic financial behaviors. The present article employs a self-determination theory (SDT; R. M. Ryan & Deci, 2000a) perspective to understand the mechanisms by which experiencing financial insecurity contributes to these detrimental outcomes. Informed by SDT, we expected that the basic psychological needs for autonomy, competence, and relatedness would drive these effects. Studies were concerned with individuals’ general experiences of financial insecurity (using community samples; Studies 1 and 2), and employed manipulations involving self-reflection (Study 3) and hypothetical scenarios (Study 4). Findings demonstrated that financially insecure conditions undermined basic psychological needs and lowered well-being (measured in terms of self-esteem, depression, and anxiety). In addition, lower satisfaction of basic psychological needs linked financial insecurity to a greater likelihood of engaging in financial cheating (Studies 2 and 3) and risky financial decisions (Study 4). Importantly, this pattern of effects remained in evidence across socioeconomically diverse samples and income levels. We discuss implications for future interventions to improve the wellness of individuals in financially insecure circumstances

    Panoramic optical and near-infrared SETI instrument: prototype design and testing

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    The Pulsed All-sky Near-infrared Optical Search for ExtraTerrestrial Intelligence (PANOSETI) is an instrument program that aims to search for fast transient signals (nano-second to seconds) of artificial or astrophysical origin. The PANOSETI instrument objective is to sample the entire observable sky during all observable time at optical and near-infrared wavelengths over 300 - 1650 nm1^1. The PANOSETI instrument is designed with a number of modular telescope units using Fresnel lenses (\sim0.5m) arranged on two geodesic domes in order to maximize sky coverage2^2. We present the prototype design and tests of these modular Fresnel telescope units. This consists of the design of mechanical components such as the lens mounting and module frame. One of the most important goals of the modules is to maintain the characteristics of the Fresnel lens under a variety of operating conditions. We discuss how we account for a range of operating temperatures, humidity, and module orientations in our design in order to minimize undesirable changes to our focal length or angular resolution.Comment: 12 pages, 8 figures, 1 tabl

    On Measuring CPCP Violation in Neutral BB-meson Decays at the Υ(4S)\Upsilon (4S) Resonance

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    Within the standard model we carry out an analysis of CPCP-violating observables in neutral BB-meson decays at the Υ(4S)\Upsilon (4S) resonance. Both time-dependent and time-integrated CPCP asymmetries are calculated, without special approximations, to meet various possible measurements at symmetric and asymmetric e+ee^{+}e^{-} BB factories. We show two ways to distinguish between direct and indirect CPCP-violating effects in the CPCP-eigenstate channels such as Bd0/Bˉd0π+πB^{0}_{d}/\bar{B}^{0}_{d}\rightarrow \pi^{+}\pi^{-} and π0KS\pi^{0} K_{S}. Reliable knowledge of the Cabibbo-Kobayashi-Maskawa phase and angles can in principle be extracted from measurements of some non-CPCP-eigenstate channels, e.g. Bd0/Bˉd0D±πB^{0}_{d}/\bar{B}^{0}_{d}\rightarrow D^{\pm}\pi^{\mp} and D()\stackrel{(-)}{D}()0KS^{(*)0}K_{S}, even in the presence of significant final-state interactions.Comment: Latex file 13 pages, CERN-TH.7194/94 and PVAMU-HEP-94-2 (Phys. Lett. B328 (1994) 477). (A few minor typing errors have been corrected.
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