658 research outputs found

    Remote lightning monitor system

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    An apparatus for monitoring, analyzing and accurately determining the value of peak current, the peak rate of change in current with respect to time and the rise time of the electrical currents generated in an electrical conductive mast that is located in the vicinity where lightning is to be monitored is described. The apparatus includes an electrical coil for sensing the change in current flowing through the mast and generating a voltage responsive. An on-site recorder and a recorder control system records the voltages produced responsive to lightning strikes and converts the voltage to digital signals for being transmitted back to the remote command station responsive to command signals. The recorder and the recorder control system are carried within an RFI proof environmental housing into which the command signals are fed by means of a fiber optic cable so as to minimize electrical interference

    Examining the Effectiveness of a Nutrition Education Intervention for Hispanic Participants

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    Background: The Expanded Food and Nutrition Education Program (EFNEP) Food Talk nutrition education curriculum in the state of Georgia was specifically tailored towards Hispanic EFNEP participants in order to test the effectiveness of the intervention in the Hispanic population. Methods: 455 Hispanic EFNEP individuals ages 18-61 in the state of Georgia participated in the data collection. Measures collected include a 24 hour diet recall, and a food behavior checklist to compare consumption and food behavior practices both before and after nutrition education intervention. Results: Measurable objectives of the study include statistically significant (p\u3c.001) in fruit, vegetable and milk consumption and consumption of fruits, vegetables and milk group foods closer to the recommended levels of USDA MyPlate guidelines for the nutrition education intervention group. Results also showed statistically significant (p\u3c.0001) improvements in nutrition-related behaviors. Conclusion: This study supports a nutrition intervention developed to improve dietary behaviors for EFNEP participants will be effective in the Hispanic population of Georgia with modifications to the nutrition education curriculum

    The Relationship Between X-ray Luminosity and Duty Cycle for Dwarf Novae and their Specific Frequency in the Inner Galaxy

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    We measure the duty cycles for an existing sample of well observed, nearby dwarf novae using data from AAVSO, and present a quantitative empirical relation between the duty cycle of dwarf novae outbursts and the X-ray luminosity of the system in quiescence. We have found that logDC=0.63(±0.21)×(logLX(ergs1)31.3)0.95(±0.1)\log DC=0.63(\pm0.21)\times(\log L_{X}({\rm erg\,s^{-1}})-31.3)-0.95(\pm0.1), where DC stands for duty cycle. We note that there is intrinsic scatter in this relation greater than what is expected from purely statistical errors. Using the dwarf nova X-ray luminosity functions from \citet{Pretorius12} and \citet{Byckling10}, we compare this relation to the number of dwarf novae in the Galactic Bulge Survey which were identified through optical outbursts during an 8-day long monitoring campaign. We find a specific frequency of X-ray bright (LX>1031ergs1L_{X}>10^{31}\,{\rm erg\,s^{-1}}) Cataclysmic Variables undergoing Dwarf Novae outbursts in the direction of the Galactic Bulge of 6.6±4.7×105M16.6\pm4.7\times10^{-5}\,M_{\odot}^{-1}. Such a specific frequency would give a Solar neighborhood space density of long period CVs of ρ=5.6±3.9×106\rho=5.6\pm3.9\times10^{-6}\,pc3^{-3}. We advocate the use of specific frequency in future work, given that projects like LSST will detect DNe well outside the distance range over which ρconst\rho\approx{\textrm const}.Comment: 9 pagers, 4 figures Accepted for publication in MNRA

    Constraining the nature of the accreting binary in CXOGBS J174623.5-310550

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    We report optical and infrared observations of the X-ray source CXOGBS J174623.5-310550. This Galactic object was identified as a potential quiescent low-mass X-ray binary accreting from an M-type donor on the basis of optical spectroscopy and the broad Halpha emission line. The analysis of X-shooter spectroscopy covering 3 consecutive nights supports an M2/3-type spectral classification. Neither radial velocity variations nor rotational broadening is detected in the photospheric lines. No periodic variability is found in I- and r'-band light curves. We derive r' = 20.8, I = 19.2 and Ks = 16.6 for the optical and infrared counterparts with the M-type star contributing 90% to the I-band light. We estimate its distance to be 1.3-1.8 kpc. The lack of radial velocity variations implies that the M-type star is not the donor star in the X-ray binary. This could be an interloper or the outer body in a hierarchical triple. We constrain the accreting binary to be a < 2.2 hr orbital period eclipsing cataclysmic variable or a low-mass X-ray binary lying in the foreground of the Galactic Bulge.Comment: (9 pages, 5 figures, accepted for publication in MNRAS

    Passive sorting of asteroid material using solar radiation pressure

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    Understanding dust dynamics in asteroid environments is key for future science missions to asteroids and, in the long-term, also for asteroid exploitation. This paper proposes a novel way of manipulating asteroid material by means of solar radiation pressure (SRP). We envisage a method for passively sorting material as a function of its grain size where SRP is used as a passive in-situ ‘mass spec-trometer’. The analysis shows that this novel method allows an effective sorting of regolith material. This has immediate applications for sample return, and in-situ resource utilisation to separate different regolith particle sizes

    The Multifragmentation Freeze--Out Volume in Heavy Ion Collisions

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    The reduced velocity correlation function for fragments from the reaction Fe + Au at 100 A~MeV bombarding energy is investigated using the dynamical--statistical approach QMD+SMM and compared to experimental data to extract the Freeze--Out volume assuming simultaneous multifragmentation.Comment: 8 pages; 3 uuencoded figures available with figures command, LateX, UCRL-J-1157

    An arcsecond view at 1-2 GHz into the Galactic Bulge

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    We present the results of a high angular resolution (1.1") and sensitivity (maximum of ~0.1 mJy) radio survey at 1-2 GHz in the Galactic Bulge. This complements the X-ray Chandra Galactic Bulge Survey, and investigates the full radio source population in this dense Galactic region. Radio counterparts to sources at other wavelengths can aid in classification, as there are relatively few types of objects that are reasonably detectable in radio at kiloparsec distances, and even fewer that are detected in both X-rays and radio. This survey covers about 3 square degrees of the Galactic Bulge Survey area (spanning the Galactic coordinate range of -3deg < l < +3deg and +1.6deg < b < +2.1deg as a first look into this region of the Galaxy with this combination of frequency, resolution, and sensitivity. Spectral indices within the observed band of 1-2 GHz were calculated for each source to assist in determining its emission mechanism. We find 1617 unique sources in the survey, 25 of which are radio counterparts to X-ray sources, and about 100 of which are steep-spectrum (alpha <~ -1.4) point sources that are viable pulsar candidates. Four radio sources are of particular interest: a compact binary; an infrared transient with an inverted radio spectrum; a potential transitional millisecond pulsar candidate; and a very steep spectrum radio source with an X-ray and bright infrared counterpart. We discuss other notable sources, including possible radio transients, potential new planetary nebulae, and active galactic nuclei.Comment: 20 pages, 13 figures. Accepted for publication in MNRA
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