2,938 research outputs found

    CO and C_2 Absorption Toward W40 IRS 1a

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    The H II region W40 harbors a small group of young, hot stars behind roughly 9 magnitudes of visual extinction. We have detected gaseous carbon monoxide (CO) and diatomic carbon (C_2) in absorption toward the star W40 IRS 1a. The 2-0 R0, R1, and R2 lines of 12CO at 2.3 micron were measured using the CSHELL on the NASA IR Telescope Facility (with upper limits placed on R3, R4, and R5) yielding an N_CO of (1.1 +/- 0.2) x 10^18 cm^-2. Excitation analysis indicates T_kin > 7 K. The Phillips system of C_2 transitions near 8775 Ang. was measured using the Kitt Peak 4-m telescope and echelle spectrometer. Radiative pumping models indicate a total C_2 column density of (7.0 +/- 0.4) x 10^14 cm^-2, two excitation temperatures (39 and 126 K), and a total gas density of n ~ 250 cm^-3. The CO ice band at 4.7 micron was not detected, placing an upper limit on the CO depletion of delta < 1 %. We postulate that the sightline has multiple translucent components and is associated with the W40 molecular cloud. Our data for W40 IRS 1a, coupled with other sightlines, shows that the ratio of CO/C_2 increases from diffuse through translucent environs. Finally, we show that the hydrogen to dust ratio seems to remain constant from diffuse to dense environments, while the CO to dust ratio apparently does not.Comment: To appear in The Astrophysical Journal 17 pages total, 5 figures Also available at http://casa.colorado.edu/~shuping/research/w40/w40.htm

    Conserved Charges in the Principal Chiral Model on a Supergroup

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    The classical principal chiral model in 1+1 dimensions with target space a compact Lie supergroup is investigated. It is shown how to construct a local conserved charge given an invariant tensor of the Lie superalgebra. We calculate the super-Poisson brackets of these currents and argue that they are finitely generated. We show how to derive an infinite number of local charges in involution. We demonstrate that these charges Poisson commute with the non-local charges of the model

    Making COVID-19-Related Decisions: A Qualitative Study of University Students

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    Background: SARS-Cov-2 (Coronavirus Disease or COVID-19) has impacted society greatly since its arrival to the United States. More specifically, college students have had to modify their behaviors on campus to minimize the spread of the virus.Purpose: The purpose of this study was to identify benefits and barriers to testing, reporting, and quarantining of undergraduate college students attending a large southeastern university.Methods: Undergraduate students were asked to complete an open-ended Qualtrics survey to share their perceived benefits and barriers to engage in behaviors to detect and prevent the spread of COVID-19. Data was analyzed via Grounded Theory techniques to determine codes and subsequent themes related to the probes.Results: Themes emerged in the categories of (a) Influencing Factors, and (b) Outcomes of the Health Behavior with 12 in the former and six in the latter. Emphasis on disclosure of COVID-19 status could be beneficial in preventing the spread of the virus on large college and university campuses.Conclusion: The data collected in this study can be used to inform COVID-19-related policies and health communication campaigns at similar colleges and universities

    Space Station Engineering Design Issues

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    Space Station Freedom topics addressed include: general design issues; issues related to utilization and operations; issues related to systems requirements and design; and management issues relevant to design

    Nitrogen Production in Starburst Galaxies Detected by GALEX

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    We investigate the production of nitrogen in star-forming galaxies with ultraviolet (UV) radiation detected by the Galaxy Evolution Explorer Satellite (GALEX). We use a sample of 8745 GALEX emission-line galaxies matched to the Sloan Digital Sky Survey (SDSS) spectroscopic sample. We derive both gas-phase oxygen and nitrogen abundances for the sample and apply stellar population synthesis models to derive stellar masses and star formation histories of the galaxies. We compare oxygen abundances derived using three different diagnostics. We derive the specific star formation rates of the galaxies by modeling the seven-band GALEX+SDSS photometry. We find that galaxies that have log (SFR/M_*) ≳ − 10.0 typically have values of log (N/O) ~ 0.05 dex less than galaxies with log (SFR/M_*) ≾ − 10.0 and similar oxygen abundances

    Design and fabrication of instrumented composite airfoils for a cryogenic wind tunnel model

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    Two instrumented horizontal stabilizers and one instrumented vertical stabilizer were designed and fabricated for testing on the Pathfinder 1 (PF-1) Transport Model in the NASA Langley Research Center's National Transonic Facility (NTF). Two different designs were employed: the horizontal stabilizer utilized a metal spar and fiberglass overwrap and the vertical stabilizer was made of all fiberglass. All design requirements were met in terms of design loads, airfoil tolerances, surface finish, orifice hole quality, and proof-of-concept tests. Pressure tubing installation was found to be easier for these concepts as compared to methods used in conventional metallic models. Ease of repair was found to be a principal advantage in that some fabrication problems were overcome by reapplying fiberglass cloth and/or epoxy to damaged areas. Also, fabrication costs were judged to be lower when compared to the more conventional design fabrication costs

    Формування законодавчої і нормативної бази архівної справи в республіці Казахстан

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    Аналізується законодавство Республіки Казахстан, спрямоване на забезпечення збереження документальної спадщини, регулювання діяльності архівної системи в умовах державного суверенітету. Визначаються особливості архівного законодавства кінця 1990-х рр., прослідковуються його зміни та напрями удосконалення в 2000-х рр., процеси формування нормативної бази архівної справи.Анализируется законодательство Республики Казахстан, направленное на обеспечение сохранности документального наследия, регулирование деятельности архивной системы в условиях государственного суверенитета. Определяются особенности архивного законодательства конца 1990-х гг., прослеживаются его изменения и направления усовершенствования в 2000- х гг., процессы формирования нормативной базы архивного дела.The legislation of Republic of Kazakhstan, directed on providing of safety of documentary legacy, adjusting of activity of the archival system in the conditions of the state sovereignty is analysed in the article. The features of the archival legislation the end of 1990-th are determined, its changes and directions of improvement in the 2000-th, the processes of forming of normative base of the archival affairs are traced

    Injury Scores and Spatial Responses of Wolves Following Capture: Cable Restraints Versus Foothold Traps

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    Wolves (Canis lupus) have been captured with foothold traps for several decades to equip them with radiocollars for population monitoring. However, trapping in most areas is limited to spring, summer, and autumn as cold winter temperatures can lead to frozen appendages in trapped animals. In addition, conflicts arise when domestic dogs encounter these traps in nonwinter seasons. An alternative capture method is the use of cable restraint devices (modified neck snares) in the winter. We evaluated injury scores, movement patterns, and space use of wolves captured in cable restraint devices and foothold traps in north‐central Minnesota, USA, during 2012–2016. Injury scores did not differ between capture techniques; however, movement patterns and space use were different. We found that the movement away from the capture site appeared to plateau by approximately 8–10 days for wolves captured by either foothold traps or cable restraints, but wolves captured in traps travelled farther away. Daily movement rates reached an asymptote approximately 14 days earlier for wolves captured with cable restraints as compared with wolves caught with foothold traps. We found the space use among wolves caught with cable restraint devices plateaued in a shorter time frame than wolves caught with foothold traps whether using days since capture (38 days earlier) or number of locations (149 locations earlier). When we controlled for seasonal effects and the presence of a capture using locational data collected 6 months later, there was no difference in space use. We concluded that wolves captured in cable restraints recovered more quickly from the capture and resumed space use and activity patterns more rapidly than wolves captured with foothold traps. Published 2019. This article is a U.S. Government work and is in the public domain in the USA

    The Diverse Properties of the Most Ultraviolet Luminous Galaxies Discovered by the Galaxy Evolution Explorer

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    We report on the properties of a sample of ultraviolet luminous galaxies (UVLGs) selected by matching the Galaxy Evolution Explorer (GALEX) Surveys with the Sloan Digital Sky Survey Third Data Release. Out of 25362 galaxies between 0.02x10^10 L_solar at 1530 Angstroms (observed wavelength). The properties of this population are well correlated with ultraviolet surface brightness. We find that the galaxies with low UV surface brightness are primarily large spiral systems with a mixture of old and young stellar populations, while the high surface brightness galaxies consist primarily of compact starburst systems. In terms of the behavior of surface brightness with luminosity, size with luminosity, the mass-metallicity relation, and other parameters, the compact UVLGs clearly depart from the trends established by the full sample of galaxies. The subset of compact UVLGs with the highest surface brightness (``supercompact UVLGs'') have characteristics that are remarkably similar to Lyman Break Galaxies at higher redshift. They are much more luminous than typical local ultraviolet-bright starburst galaxies and blue compact dwarf galaxies. They have metallicities that are systematically lower than normal galaxies of the same stellar mass, indicating that they are less chemically evolved. In all these respects, they are the best local analogs for Lyman Break Galaxies.Comment: Fixed error in ObjID column of Table 1. 30 pages, 12 figures. Accepted for the GALEX special issue of ApJS. Abstract abridge
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