1,562 research outputs found
NH3 in IRC plus 10216
Ammonia was detected in the circumstellar envelope of IRC +10216 by means of three infrared absorption lines in the nu sup 2 band around 950/cm. The lines are fully resolved at a resolution of 0.22 km/sec and indicate that most of the circumstellar gas is accelerated to expansion velocities around 14 km/sec within a few stellar radii. The NH3 profiles indicate a rotational temperature between 400 and 700 K, and H2 density between 10 to the 8th power/cu cm and 10 to the 10th power/cu cm, and NH3 column density of 10 to the 17th power/sq cm. The H2 density indicates that the mass of the circumstellar envelope within a 1 arcsec radius is approximately 0.1 solar masses
The brightness distribution of IRC +10216 at 11 microns
The brightness distribution of IRC +10216 at a wavelength of 11 microns was measured in detail using a spatial interferometer. This brightness distribution appears to have azimuthal symmetry; an upper limit of 1.1 may be set to the ellipticity at 11 microns if the object has a major axis oriented either along or perpendicular to the major axis of the optical image. The radial distribution shows both compact and extended emission. The extended component, which is due to thermal emission from circumstellar dust, contributes 91% of the total flux and has a 1/e diameter of 0.90 minutes. The tapered shape of this component is consistent with a l/r squared dust density dependence. The compact component is unresolved (less than 0.2 minutes in diameter) and represents emission from the central star seen through the circumstellar envelope
Spatial heterodyne interferometry of VY Canis Major's, alpha Orionis, alpha Scorpii, and R leonis at 11 microns
Using the technique of heterodyne interferometry, measurements were made of the spatial distribution of 11 micron radiation from four late type stars. The circumstellar shells surrounding VY Canis Majoris, alpha Orionis, and alpha Scorpii were resolved, whereas that of R Leonis was only partially resolved at a fringe spacing of 0.4 sec
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A continuously updated, geospatially rectified database of utility-scale wind turbines in the United States.
Over 60,000 utility-scale wind turbines are installed in the United States as of October, 2019, representing over 97 gigawatts of electric power capacity; US wind turbine installations continue to grow at a rapid pace. Yet, until April 2018, no publicly-available, regularly updated data source existed to describe those turbines and their locations. Under a cooperative research and development agreement, analysts from three organizations collaborated to develop and release the United States Wind Turbine Database (USWTDB) - a publicly available, continuously updated, spatially rectified data source of locations and attributes of utility-scale wind turbines in the United States. Technical specifications and wind facility data, incorporated from five sources, undergo rigorous quality control. The location of each turbine is visually verified using high-resolution aerial imagery. The quarterly-updated data are available in a variety of formats, including an interactive web application, comma-separated values (CSV), shapefile, and application programming interface (API). The data are used widely by academic researchers, engineers and developers from wind energy companies, government agencies, planners, educators, and the general public
Properties of Nucleon Resonances by means of a Genetic Algorithm
We present an optimization scheme that employs a Genetic Algorithm (GA) to
determine the properties of low-lying nucleon excitations within a realistic
photo-pion production model based upon an effective Lagrangian. We show that
with this modern optimization technique it is possible to reliably assess the
parameters of the resonances and the associated error bars as well as to
identify weaknesses in the models. To illustrate the problems the optimization
process may encounter, we provide results obtained for the nucleon resonances
(1230) and (1700). The former can be easily isolated and thus
has been studied in depth, while the latter is not as well known
experimentally.Comment: 12 pages, 10 figures, 3 tables. Minor correction
Open defecation and childhood stunting in India: an ecological analysis of new data from 112 districts.
Poor sanitation remains a major public health concern linked to several important health outcomes; emerging evidence indicates a link to childhood stunting. In India over half of the population defecates in the open; the prevalence of stunting remains very high. Recently published data on levels of stunting in 112 districts of India provide an opportunity to explore the relationship between levels of open defecation and stunting within this population. We conducted an ecological regression analysis to assess the association between the prevalence of open defecation and stunting after adjustment for potential confounding factors. Data from the 2011 HUNGaMA survey was used for the outcome of interest, stunting; data from the 2011 Indian Census for the same districts was used for the exposure of interest, open defecation. After adjustment for various potential confounding factors--including socio-economic status, maternal education and calorie availability--a 10 percent increase in open defecation was associated with a 0.7 percentage point increase in both stunting and severe stunting. Differences in open defecation can statistically account for 35 to 55 percent of the average difference in stunting between districts identified as low-performing and high-performing in the HUNGaMA data. In addition, using a Monte Carlo simulation, we explored the effect on statistical power of the common practice of dichotomizing continuous height data into binary stunting indicators. Our simulation showed that dichotomization of height sacrifices statistical power, suggesting that our estimate of the association between open defecation and stunting may be a lower bound. Whilst our analysis is ecological and therefore vulnerable to residual confounding, these findings use the most recently collected large-scale data from India to add to a growing body of suggestive evidence for an effect of poor sanitation on human growth. New intervention studies, currently underway, may shed more light on this important issue
A Strategic Approach to Public Health Workforce Development and Capacity Building
In February 2010, CDC’s National Center for HIV/AIDS, Viral Hepatitis, Sexually Transmitted Disease (STD), and Tuberculosis (TB) Prevention (NCHHSTP) formally institutionalized workforce development and capacity building (WDCB) as one of six overarching goals in its 2010–2015 Strategic Plan. Annually, workforce team members finalize an action plan that lays the foundation for programs to be implemented for NCHHSTP’s workforce that year. This paper describes selected WDCB programs implemented by NCHHSTP during the last 4 years in the three strategic goal areas: (1) attracting, recruiting, and retaining a diverse and sustainable workforce; (2) providing staff with development opportunities to ensure the effective and innovative delivery of NCHHSTP programs; and (3) continuously recognizing performance and achievements of staff and creating an atmosphere that promotes a healthy work–life balance. Programs have included but are not limited to an Ambassador Program for new hires, career development training for all staff, leadership and coaching for mid-level managers, and a Laboratory Workforce Development Initiative for laboratory scientists. Additionally, the paper discusses three overarching areas—employee communication, evaluation and continuous review to guide program development, and the implementation of key organizational and leadership structures to ensure accountability and continuity of programs. Since 2010, many lessons have been learned regarding strategic approaches to scaling up organization-wide public health workforce development and capacity building. Perhaps the most important is the value of ensuring the high-level strategic prioritization of this issue, demonstrating to staff and partners the importance of this imperative in achieving NCHHSTP’s mission
Oersted Lecture 2014: Physics education research and teaching modern Modern Physics
Citation: Zollman, D. (2016). Oersted Lecture 2014: Physics education research and teaching modern Modern Physics. American Journal of Physics, 84(8), 573-580. doi:10.1119/1.4953824Modern Physics has been used as a label for most of physics that was developed since the discovery of X-rays in 1895. Yet, we are teaching students who would not use the label "modern" for anything that happened before about 1995, when they were born. So, are we and our students in worlds that differ by a century? In addition to content, sometimes our students and we have differing views about methods and styles of teaching. A modern course in any topic of physics should include applications of contemporary research in physics education and the learning sciences as well as research and developments in methods of delivering the content. Thus, when we consider teaching Modern Physics, we are challenged with deciding what the content should be, how to adjust for the ever increasing information on how students learn physics, and the constantly changing tools that are available to us for teaching and learning. When we mix all of these together, we can teach modern Modern Physics or maybe teach Modern Physics modernly. © 2016 American Association of Physics Teachers
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