8,851 research outputs found
The Effect of Attending a Small Class in the Early Grades on College-Test Taking and Middle School Test Results: Evidence from Project STAR.
Human Factors Engineering Requirements for the International Space Station - Successes and Challenges
Advanced technology coupled with the desire to explore space has resulted in increasingly longer human space missions. Indeed, any exploration mission outside of Earth's neighborhood, in other words, beyond the moon, will necessarily be several months or even years. The International Space Station (ISS) serves as an important advancement toward executing a successful human space mission that is longer than a standard trip around the world or to the moon. The ISS, which is a permanently occupied microgravity research facility orbiting the earth, will support missions four to six months in duration. In planning for the ISS, the NASA developed an agency-wide set of human factors standards for the first time in a space exploration program. The Man-Systems Integration Standard (MSIS), NASA-STD-3000, a multi-volume set of guidelines for human-centered design in microgravity, was developed with the cooperation of human factors experts from various NASA centers, industry, academia, and other government agencies. The ISS program formed a human factors team analogous to any major engineering subsystem. This team develops and maintains the human factors requirements regarding end-to-end architecture design and performance, hardware and software design requirements, and test and verification requirements. It is also responsible for providing program integration across all of the larger scale elements, smaller scale hardware, and international partners
Traumatic Myiasis Caused by an Association of <i>Sarcophaga tibialis</i> (Diptera: Sarcophagidae) and <i>Lucilia sericata</i> (Diptera: Calliphoridae) in a Domestic Cat in Italy
received: 2015-05-07 accepted: 2015-06-30 published: 2015-08-25© 2015, Korean Society for Parasitology and Tropical Medicine
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The attached file is the published version of the article.© 2015, Korean Society for Parasitology and Tropical Medicine
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The attached file is the published version of the article
Accurate photometry of extended spherically symmetric sources
We present a new method to derive reliable photometry of extended spherically
symmetric sources from {\it HST} images (WFPC2, ACS/WFC and NICMOS/NIC2
cameras), extending existing studies of point sources and marginally resolved
sources. We develop a new approach to accurately determine intrinsic sizes of
extended spherically symmetric sources, such as star clusters in galaxies
beyond the Local Group (at distances <~ 20 Mpc), and provide a detailed
cookbook to perform aperture photometry on such sources, by determining
size-dependent aperture corrections (ACs) and taking sky oversubtraction as a
function of source size into account. In an extensive Appendix, we provide the
parameters of polynomial relations between the FWHM of various input profiles
and those obtained by fitting a Gaussian profile (which we have used for
reasons of computational robustness, although the exact model profile used is
irrelevant), and between the intrinsic and measured FWHM of the cluster and the
derived AC. Both relations are given for a number of physically relevant
cluster light profiles, intrinsic and observational parameters. AC relations
are provided for a wide range of apertures. Depending on the size of the source
and the annuli used for the photometry, the absolute magnitude of such extended
objects can be underestimated by up to 3 mag, corresponding to an error in mass
of a factor of 15. We carefully compare our results to those from the more
widely used DeltaMag method, and find an improvement of a factor of 3--40 in
both the size determination and the AC.Comment: The paper is accepted for publication in A&A, Section 13
(Observational Techniques, published electronically). The published version
contains one example table per appendix. A version of the paper containing
all tables as well as all data in electronical form are available
http://www.astro.physik.uni-goettingen.de/~galev/panders/Sizes_AC
Protection of Works of Art From Atmospheric Ozone
Assesses the colorfastness of organic colorants and watercolor pigments tested in atmospheric ozone. A summary of a full report of the Environmental Quality Laboratory, California Institute of Technology, Pasadena
Childhood Disadvantage and Obesity: Is Nurture Trumping Nature?
Obesity has been one of the fastest growing health concerns among children, particularly among disadvantaged children. For children overall, obesity rates have tripled from 5% in the early 1970s to about 15% by the early 2000s. For disadvantaged children, obesity rates are closer to 20%. In this paper, we first examine the impact of various measures of disadvantage on children's weight outcomes over the past 30 years, finding that the disadvantaged have gained weight faster. Over the same period, adult obesity rates have grown, and we expect parental obesity to be closely tied to children's obesity, for reasons of both nature and nurture. Thus, examining changes in the parent-child correlation in BMI should give us some insight into the ways in which the environment that parents and children share has affected children's body mass, or into how the interaction of genes and environment has changed. We find that the elasticity between mothers' and children's BMI has increased since the 1970s, suggesting that shared genetic-environmental factors have become more important in determining obesity. Despite the faster weight gain for the disadvantaged, there appears to be no clear difference for by disadvantaged group in either the parent-child elasticity or in identifiable environmental factors. On average, the increases in parents' BMI between the early 1970s and the early 2000s can explain about 37 percent of the increase in children's BMI. Although common environmental/genetic factors play a larger role now than in earlier time periods, child specific environments such as schools and day care play a potentially important role in determining children's health status.
- …
