391 research outputs found

    Characterization of coarse aggregate angularity using digital image processing

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    This thesis involves a comparative analysis between well-established physically performed measurements for coarse aggregate and an image-based system. A thorough literature review was conducted, focusing on the importance of aggregate shape and how it is measured. In addition, state of the art in image-based aggregate measurement was reviewed along with the impacts and difficulties of an image-based methodology. Physical testing, consisting of Uncompacted Void Content, Index of Particle Shape and Texture (Compacted Voids), and Percent of Fractured Particles (fractured face or crush counts), was performed on aggregate control samples prior to testing on bulk aggregate samples. All aggregate samples were then tested with the WipShape imaging system to obtain Minimum Average Curve Radius measurement data. Finally, the results of physical testing and Minimum Average Curve Radius measurements were analyzed to determine if correlations exist between the different methods --Introduction, page 2-3

    Remotely Readable Fiber Optic Compass

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    PatentA remotely readable fiber optic compass. A sheet polarizer is affixed to a magnet rotatably mounted in a compass body, such that the polarizer rotates with the magnet. The optical axis of the sheet polarizer is preferably aligned with the north-south axis of the magnet. A single excitation light beam is divided into four identical beams, two of which are passed through the sheet polarizer and through two fixed polarizing sheets which have their optical axes at right angles to one another. The angle of the compass magnet with respect to a fixed axis of the compass body can be determined by measuring the ratio of the intensities of the two light beams. The remaining ambiguity as to which of the four possible quadrants the magnet is pointing to is resolved by the second pair of light beams, which are passed through the sheet polarizer at positions which are transected by two semicircular opaque strips formed on the sheet polarizer. The incoming excitation beam and the four return beams are communicated by means of optical fibers, giving a remotely readable compass which has no electrical parts

    From the Field

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    These short pieces, written by individuals engaged in sex work-related activism and scholarship, are intended to provide a snapshot of ongoing social justice efforts regarding this highly politicized issue. In the following commentaries, Sienna Baskin documents U.S. efforts to provide legal aid to sex workers and victim-survivors of sex trafficking, Thaddeus Blanchette describes a Brazilian prostitute’s campaign for a seat in Congress, Megan Morgenson speaks to the need to incorporate sex workers’ perspectives into anti-trafficking initiatives, Sarah Jenny Bleviss documents new mobile phone technology designed to help U.S. sex workers navigate the risks they face working in a criminalized profession, and Gregory Mitchell (together with Thaddeus Blanchette) and Jayne Swift detail two events on U.S. campuses designed to promote critical thinking about sex work and trafficking

    Analyzing Math-to-Mastery through Brief Experimental Analysis

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    The current study evaluated the effectiveness of individualized math-to-mastery (MTM) interventions, selected though brief experimental analysis (BEA), at increasing math fluency skills for 3 elementary-aged females. As MTM has only been investigated as a multicomponent intervention, the present study utilized BEA to identify those specific components which led to math skills gains in the most efficient manner possible. BEA results indicated that for 2 of 3 participants only a partial MTM intervention was necessary to prompt fluency gains, while the entire intervention was the most effective for the third. During extended analysis all 3 participants displayed math skills gains above those seen during repeated baseline assessments. Results are discussed in terms of further refining MTM through BEA procedures so as to individually target math skill deficits by considering both intervention effectiveness and efficiency

    Kepler-445, Kepler-446 And The Occurrence Of Compact Multiples Orbiting Mid-M Dwarf Stars

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    We confirm and characterize the exoplanetary systems Kepler-445 and Kepler-446: two mid-M dwarf stars, each with multiple, small, short-period transiting planets. Kepler-445 is a metal-rich ([ Fe/H] = + 0.25 0.10) M4 dwarf with three transiting planets, and Kepler-446 is a metal-poor ([ Fe/H] = -0.30 0.10) M4 dwarf also with three transiting planets. Kepler-445c is similar toGJ 1214b: both in planetary radius and the properties of the host star. The Kepler-446 system is similar to the Kepler-42 system: both are metal-poor with large galactic space velocities and three short-period, likely rocky transiting planets that were initially assigned erroneously large planet-to-star radius ratios. We independently determined stellar parameters from spectroscopy and searched for and fitted the transit light curves for the planets, imposing a strict prior on stellar density in order to remove correlations between the fitted impact parameter and planet-to-star radius ratio for short-duration transits. Combining Kepler-445, Kepler-446, and Kepler-42, and isolating all mid-M dwarf stars observed by Kepler with the precision necessary to detect similar systems, we calculate that 21+ 7 -5 % of mid-M dwarf stars host compact multiples ( multiple planets with periods of less than 10 days) for a wide range of metallicities. We suggest that the inferred planet masses for these systems support highly efficient accretion of protoplanetary disk metals by mid-M dwarf protoplanets.NSF DGE1144152, AST-1005313NASA NAS5-26555NASA Office of Space Science NNX13AC07GAstronom

    Touchstone Stars: Highlights from the Cool Stars 18 Splinter Session

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    We present a summary of the splinter session on "touchstone stars" -- stars with directly measured parameters -- that was organized as part of the Cool Stars 18 conference. We discuss several methods to precisely determine cool star properties such as masses and radii from eclipsing binaries, and radii and effective temperatures from interferometry. We highlight recent results in identifying and measuring parameters for touchstone stars, and ongoing efforts to use touchstone stars to determine parameters for other stars. We conclude by comparing the results of touchstone stars with cool star models, noting some unusual patterns in the differences.Comment: Proceedings of the 18th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Eds G. van Belle & H. Harri

    Risk of vicarious trauma in nursing research:a focused mapping review and synthesis

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    AIMS AND OBJECTIVES: To provide a snapshot of how vicarious trauma is considered within the published nursing research literature. BACKGROUND: Vicarious trauma (secondary traumatic stress) has been the focus of attention in nursing practice for many years. The most pertinent areas to invoke vicarious trauma in research have been suggested as abuse/violence and death/dying. What is not known is how researchers account for the risks of vicarious trauma in research. DESIGN: Focused mapping review and synthesis. Empirical studies meeting criteria for abuse/violence or death/dying in relevant Scopus ranked top nursing journals (n = 6) January 2009 to December 2014. METHODS: Relevant papers were scrutinised for the extent to which researchers discussed the risk of vicarious trauma. Aspects of the studies were mapped systematically to a pre-defined template, allowing patterns and gaps in authors' reporting to be determined. These were synthesised into a coherent profile of current reporting practices and from this, a new conceptualisation seeking to anticipate and address the risk of vicarious trauma was developed. RESULTS: Two thousand five hundred and three papers were published during the review period, of which 104 met the inclusion criteria. Studies were distributed evenly by method (52 qualitative; 51 quantitative; one mixed methods) and by focus (54 abuse/violence; 50 death/dying). The majority of studies (98) were carried out in adult populations. Only two papers reported on vicarious trauma. CONCLUSION: The conceptualisation of vicarious trauma takes account of both sensitivity of the substantive data collected, and closeness of those involved with the research. This might assist researchers in designing ethical and protective research and foreground the importance of managing risks of vicarious trauma. RELEVANCE TO CLINICAL PRACTICE: Vicarious trauma is not well considered in research into clinically important topics. Our proposed framework allows for consideration of these so that precautionary measures can be put in place to minimise harm to staff

    Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664

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    Several low-mass eclipsing binary stars show larger than expected radii for their measured mass, metallicity, and age. One proposed mechanism for this radius inflation involves inhibited internal convection and starspots caused by strong magnetic fields. One particular eclipsing binary, T-Cyg1-12664, has proven confounding to this scenario. Çakırlı et al. measured a radius for the secondary component that is twice as large as model predictions for stars with the same mass and age, but a primary mass that is consistent with predictions. Iglesias-Marzoa et al. independently measured the radii and masses of the component stars and found that the radius of the secondary is not in fact inflated with respect to models, but that the primary is, which is consistent with the inhibited convection scenario. However, in their mass determinations, Iglesias-Marzoa et al. lacked independent radial velocity measurements for the secondary component due to the star's faintness at optical wavelengths. The secondary component is especially interesting, as its purported mass is near the transition from partially convective to a fully convective interior. In this article, we independently determined the masses and radii of the component stars of T-Cyg1-12664 using archival Kepler data and radial velocity measurements of both component stars obtained with IGRINS on the Discovery Channel Telescope and NIRSPEC and HIRES on the Keck Telescopes. We show that neither of the component stars is inflated with respect to models. Our results are broadly consistent with modern stellar evolutionary models for main-sequence M dwarf stars and do not require inhibited convection by magnetic fields to account for the stellar radii

    Low fitness partially explains resting metabolic rate differences between African American and white women

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    Background High levels of obesity among African American women have been hypothesized to be partially resultant from a lower resting metabolic rate compared with white women. The aim of the current study was to determine if differences in cardiorespiratory fitness and moderate-to-vigorous physical activity are associated with differences in resting metabolic rate among free-living young adult African American women and white women. Methods Participants were 179 women (white women n = 141, African American women n = 38, mean age = 27.7 years). Resting metabolic rate was measured using indirect calorimetry, body composition using dual energy x-ray absorptiometry, cardiorespiratory fitness via maximal treadmill test, and moderate-to-vigorous physical activity using an activity monitor. Results African American women had higher body mass index, fat mass, and fat-free mass compared with white women but lower levels of cardiorespiratory fitness. No differences were observed between African American and white women in resting metabolic rate when expressed as kcal/day (1390.8 ± 197.5 vs 1375.7 ± 173.6 kcal/day, P =.64), but African American women had a lower resting metabolic rate when expressed relative to body weight (2.56 ± 0.30 vs 2.95 ± 0.33 mL/kg/min,

    Living with Uncertainty

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    The last few years have seen a major rethinking of some of the hallowed assumptions of range ecology and range management practice. This book examines the management of policy implications of this new ecological thinking for pastoral development in dryland areas. With examples drawn from all over Africa, the contributors examine the consequences of living with uncertainty for pastoral development planning, range and fodder management, drought responses, livestock marketing, resource tenure, institutional development and pastoral administration
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