5,837 research outputs found

    Collecting Data from Children Ages 9-13

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    Provides a summary of literature on common methods used to collect data, such as diaries, interviews, observational methods, and surveys. Analyzes age group-specific considerations, advantages, and drawbacks, with tips for improving data quality

    SOCIAL IMPLICATIONS OF THE INTERNET

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    The Internet is a critically important research site for sociologists testing theories of technology diffusion and media effects, particularly because it is a medium uniquely capable of integrating modes of communication and forms of content. Current research tends to focus on the Internetā€™s implications in five domains: 1) inequality (the ā€œdigital divideā€); 2) community and social capital; 3) political participation; 4) organizations and other economic institutions; and 5) cultural participation and cultural diversity. A recurrent theme across domains is that the Internet tends to complement rather than displace existing media and patterns of behavior. Thus in each domain, utopian claims and dystopic warnings based on extrapolations from technical possibilities have given way to more nuanced and circumscribed understandings of how Internet use adapts to existing patterns, permits certain innovations, and reinforces particular kinds of change. Moreover, in each domain the ultimate social implications of this new technology depend on economic, legal, and policy decisions that are shaping the Internet as it becomes institutionalized. Sociologists need to study the Internet more actively and, particularly, to synthesize research findings on individual user behavior with macroscopic analyses of institutional and political-economic factors that constrain that behavior.World Wide Web, communications, media, technology

    Discovery of Strong Lensing by an Elliptical Galaxy at z=0.0345

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    We have discovered strong gravitational lensing by the galaxy ESO325-G004, in images obtained with the Advanced Camera for Surveys on the Hubble Space Telescope. The lens galaxy is a boxy group-dominant elliptical at z=0.0345, making this the closest known galaxy-scale lensing system. The lensed object is very blue (B-I = 1.1), and forms two prominent arcs and a less extended third image. The Einstein radius is R_Ein=1.9 kpc (~3 arcsec on the sky, cf. 12 arcsec effective radius of the lens galaxy). Assuming a high redshift for the source, the mass within R_Ein is 1.4x10^11 M_sun, and the I-band mass-to-light ratio is 1.8 (M/L)_sun. The equivalent velocity dispersion is sigma_lens=310 km/s, in excellent agreement with the measured stellar dispersion sigma_v=320 km/s. Modeling the lensing potential with a singular isothermal ellipse (SIE), we find close agreement with the light distribution. The best fit SIE model reproduces the ellipticity of the lens galaxy to ~10%, and its position angle within 1 degree. The model predicts the broad features of the arc geometry as observed; the unlensed magnitude of the source is estimated at I ~ 23.75. We suggest that one in ~200 similarly-massive galaxies within z<0.1 will exhibit such a luminous multiply-imaged source.Comment: Five pages, three figures; accepted by Astrophysical Journal Letter

    Charged Higgs bosons from the 3-3-1 models and the R(D(āˆ—))\mathcal{R}(D^{(*)}) anomalies

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    Several anomalies in the semileptonic B-meson decays such as R(D(āˆ—))\mathcal{R}(D^{(*)}) have been reported by BABARBABAR, Belle, and LHCb collaborations recently. In this paper, we investigate the contributions of the charged Higgs bosons from the 3-3-1 models to the R(D(āˆ—))\mathcal{R}(D^{(*)}) anomalies. We find that, in a wide range of parameter space, the 3-3-1 models might give reasonable explanations to the R(D(āˆ—))\mathcal{R}(D^{(*)}) anomalies and other analogous anomalies of the B meson's semileptonic decays.Comment: Accpeted by Physical Review

    Economic phases of erosion control in southern Iowa and northern Missouri

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    The Soil Erosion Service of the United States Department of Agriculture has 32 Erosion Control Projects under way in 31 states. More projects will be initiated in the near future. One of these demonstrational and experimental projects embraces about 152,000 acres of the Big Creek watershed area in Ringgold and Decatur counties, Iowa, and Harrison County, Missouri. The headquarters for this project of the Soil Erosion Service are at Bethany, Mo. The government invites the farmers of this area to enter a cooperative agreement, under which the Soil Erosion Service agrees to assist the farmer in controlling erosion, and the farmer agrees to follow an erosion control program for 5 years. This program is worked out individually, for each cooperating farmer, by the farmer himself and the soil erosion experts. The government furnishes special equipment for terracing and gully control, as well as a portion of the seed, fertilizer and limestone necessary for an erosion control program

    Multi-Wavelength Implications of the Companion Star in Eta Carinae

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    Eta Carinae is considered to be a massive colliding wind binary system with a highly eccentric (e \sim 0.9), 5.54-yr orbit. However, the companion star continues to evade direct detection as the primary dwarfs its emission at most wavelengths. Using three-dimensional (3-D) SPH simulations of Eta Car's colliding winds and radiative transfer codes, we are able to compute synthetic observables across multiple wavebands for comparison to the observations. The models show that the presence of a companion star has a profound influence on the observed HST/STIS UV spectrum and H-alpha line profiles, as well as the ground-based photometric monitoring. Here, we focus on the Bore Hole effect, wherein the fast wind from the hot secondary star carves a cavity in the dense primary wind, allowing increased escape of radiation from the hotter/deeper layers of the primary's extended wind photosphere. The results have important implications for interpretations of Eta Car's observables at multiple wavelengths.Comment: 5 pages, 4 figures, To be published in the proceedings of the meeting 'Four Decades of Research on Massive Stars' in honor of Tony Moffat, 11-15 July 2011, Saint-Michel-des-Saints, Quebe
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