6,063 research outputs found
Binary Central Stars of Planetary Nebulae Discovered Through Photometric Variability III: The Central Star of Abell 65
A growing number of close binary stars are being discovered among central
stars of planetary nebulae. Recent and ongoing surveys are finding new systems
and contributing to our knowledge of the evolution of close binary systems. The
push to find more systems was largely based on early discoveries which
suggested that 10 to 15% of all central stars are close binaries. One goal of
this series of papers is confirmation and classification of these systems as
close binaries and determination of binary system parameters. Here we provide
time-resolved multi-wavelength photometry of the central star of Abell 65 as
well as further analysis of the nebula and discussion of possible
binary--nebula connections. Our results for Abell 65 confirm recent work
showing that it has a close, cool binary companion, though several of our model
parameters disagree with the recently published values. With our longer time
baseline of photometric observations from 1989--2009 we also provide a more
precise orbital period of 1.0037577 days.Comment: Accepted for publication in the Astronomical Journa
Transport processes of particles in dilute suspensions in turbulent water flow—phase III
Understanding the basic mechanisms and predicting the behavior of particles suspended in turbulent fluid flow are essential to environmental conservation and to multiphase system design. Air and water pollution, sedimentation and erosion of river beds and coastal shorelines, and atmospheric fallout are some of the areas in which particle suspensions are of key importance. Detailed experimental measurements of dilute particle suspensions have been performed which examined the effects of particle size, shape and relative density on the statistical response of such particles in a turbulent fluid. Shape was found to be of minor importance for spheres, cubes and tetrahedrons. However, size was found to be important when the particle dimension was as large or larger than the fluid turbulence structure. Relative density influenced both free fall and inertial effects. An analytical model was developed which included these latter effects. It agrees well with observed particle dispersion measurements.U.S. Department of the InteriorU.S. Geological SurveyOpe
Qualitative process evaluation of an Australian alcohol media literacy study: recommendations for designing culturally responsive school-based programs
Background: Alcohol media literacy programs seek to mitigate the potentially harmful effects of alcohol advertising on children\u27s drinking intentions and behaviours through equipping them with skills to challenge media messages. In order for such programs to be effective, the teaching and learning experiences must be tailored to their specific cultural context. Media in the Spotlight is an alcohol media literacy program aimed at 9 to 12 year old Australian children. This study evaluates the process and implementation of the program, outlining the factors that facilitated and inhibited implementation. From this evaluation, a pedagogical framework has been developed for health professionals implementing culturally responsive programs in school settings. Methods: Process measures included: semi-structured interviews with teachers before and after the program was implemented (n = 11 interviews), program evaluation questionnaires completed by children (n = 166), lesson observations completed by teachers (n = 35 observations), and reflective journal entries completed by the researcher (n = 44 entries). A thematic analysis approach was used to analyse all of the data sets using NVivo. Inductive coding was used, whereby the findings were derived from the research objectives and multiple readings and interpretations of the data. Results: Five key pedagogical considerations were identified that facilitated implementation. These were: connecting to the students\u27 life worlds to achieve cultural significance; empowering students with real-world skills to ensure relevance; ensuring programs are well structured with strong connections to the school curriculum; creating developmentally appropriate activities while providing a range of assessment opportunities; and including hands-on and interactive activities to promote student engagement. Three potential inhibitors to implementing the alcohol media literacy program in upper-elementary school classrooms were identified. These included topic sensitivities, classroom management challenges, and fitting new programs into already busy school schedules. Conclusion: Overall, the program content and individual lessons were well received by the teachers and students. The lessons learned from the development, implementation and evaluation of this program can provide health professionals with key pedagogical strategies for designing culturally responsive educational programs. Culturally responsive programs are critical for ensuring interventions are effective for their specific context
Obesity and the food environment: income and ethnicity differences among people with diabetes: the Diabetes Study of Northern California (DISTANCE).
ObjectiveIt is unknown whether any association between neighborhood food environment and obesity varies according to individual income and/or race/ethnicity. The objectives of this study were to test whether there was an association between food environments and obesity among adults with diabetes and whether this relationship differed according to individual income or race/ethnicity.Research design and methodsSubjects (n = 16,057) were participants in the Diabetes Study of Northern California survey. Kernel density estimation was used to create a food environment score for each individual's residence address that reflected the mix of healthful and unhealthful food vendors nearby. Logistic regression models estimated the association between the modeled food environment and obesity, controlling for confounders, and testing for interactions between food environment and race/ethnicity and income.ResultsThe authors found that more healthful food environments were associated with lower obesity in the highest income groups (incomes 301-600% and >600% of U.S. poverty line) among whites, Latinos, and Asians. The association was negative, but smaller and not statistically significant, among high-income blacks. On the contrary, a more healthful food environment was associated with higher obesity among participants in the lowest-income group (<100% poverty threshold), which was statistically significant for black participants in this income category.ConclusionsThese findings suggest that the availability of healthful food environments may have different health implications when financial resources are severely constrained
IMBES pre-conference: using insight from research to improve education
In September 2016, the International Mind, Brain, and Education Society (IMBES) biennial conference took place in Toronto, Canada. The pre-conference (organized by the Wellcome Trust) was designed to share new findings, lessons learned, and inspirational innovation within the field, and to encourage the community to not only identify current challenges, but to start planning potential ways to address them. This article provides a brief summary of the discussions from the day, and suggests steps that members of the community, conference organizers, and funders can take in helping to move the field forward. Finally, it outlines new work Wellcome has commissioned since the conference in response to some of the challenges defined on the day
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Assessing rotation-invariant feature classification for automated wildebeest population counts
Accurate and on-demand animal population counts are the holy grail for wildlife conservation organizations throughout the world because they enable fast and responsive adaptive management policies. While the collection of image data from camera traps, satellites, and manned or unmanned aircraft has advanced significantly, the detection and identification of animals within images remains a major bottleneck since counting is primarily conducted by dedicated enumerators or citizen scientists. Recent developments in the field of computer vision suggest a potential resolution to this issue through the use of rotation-invariant object descriptors combined with machine learning algorithms. Here we implement an algorithm to detect and count wildebeest from aerial images collected in the Serengeti National Park in 2009 as part of the biennial wildebeest count. We find that the per image error rates are greater than, but comparable to, two separate human counts. For the total count, the algorithm is more accurate than both manual counts, suggesting that human counters have a tendency to systematically over or under count images. While the accuracy of the algorithm is not yet at an acceptable level for fully automatic counts, our results show this method is a promising avenue for further research and we highlight specific areas where future research should focus in order to develop fast and accurate enumeration of aerial count data. If combined with a bespoke image collection protocol, this approach may yield a fully automated wildebeest count in the near future
A Hot Uranus Orbiting the Super Metal-rich Star HD77338 and the Metallicity - Mass Connection
We announce the discovery of a low-mass planet orbiting the super metal-rich
K0V star HD77338 as part of our on-going Calan-Hertfordshire Extrasolar Planet
Search. The best fit planet solution has an orbital period of 5.7361\pm0.0015
days and with a radial velocity semi-amplitude of only 5.96\pm1.74 m/s, we find
a minimum mass of 15.9+4.7-5.3 Me. The best fit eccentricity from this solution
is 0.09+0.25-0.09, and we find agreement for this data set using a Bayesian
analysis and a periodogram analysis. We measure a metallicity for the star of
+0.35\pm0.06 dex, whereas another recent work (Trevisan et al. 2011) finds
+0.47\pm0.05 dex. Thus HD77338b is one of the most metal-rich planet host stars
known and the most metal-rich star hosting a sub-Neptune mass planet. We
searched for a transit signature of HD77338b but none was detected. We also
highlight an emerging trend where metallicity and mass seem to correlate at
very low masses, a discovery that would be in agreement with the core accretion
model of planet formation. The trend appears to show that for Neptune-mass
planets and below, higher masses are preferred when the host star is more
metal-rich. Also a lower boundary is apparent in the super metal-rich regime
where there are no very low-mass planets yet discovered in comparison to the
sub-solar metallicity regime. A Monte Carlo analysis shows that this, low-mass
planet desert, is statistically significant with the current sample of 36
planets at around the 4.5\sigma\ level. In addition, results from Kepler
strengthen the claim for this paucity of the lowest-mass planets in super
metal-rich systems. Finally, this discovery adds to the growing population of
low-mass planets around low-mass and metal-rich stars and shows that very
low-mass planets can now be discovered with a relatively small number of data
points using stable instrumentation.Comment: 25 pages, 15 figures, 5 tables, accepted for publication in Ap
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