83 research outputs found
Three-Phased Wake Vortex Decay
A detailed parametric study is conducted that examines vortex decay within turbulent and stratified atmospheres. The study uses a large eddy simulation model to simulate the out-of-ground effect behavior of wake vortices due to their interaction with atmospheric turbulence and thermal stratification. This paper presents results from a parametric investigation and suggests improvements for existing fast-time wake prediction models. This paper also describes a three-phased decay for wake vortices. The third phase is characterized by a relatively slow rate of circulation decay, and is associated with the ringvortex stage that occurs following vortex linking. The three-phased decay is most prevalent for wakes imbedded within environments having low-turbulence and near-neutral stratification
Extragalactic millimeter-wave point source catalog, number counts and statistics from 771 square degrees of the SPT-SZ Survey
We present a point source catalog from 771 square degrees of the South Pole
Telescope Sunyaev Zel'dovich (SPT-SZ) survey at 95, 150, and 220 GHz. We detect
1545 sources above 4.5 sigma significance in at least one band. Based on their
relative brightness between survey bands, we classify the sources into two
populations, one dominated by synchrotron emission from active galactic nuclei,
and one dominated by thermal emission from dust-enshrouded star-forming
galaxies. We find 1238 synchrotron and 307 dusty sources. We cross-match all
sources against external catalogs and find 189 unidentified synchrotron sources
and 189 unidentified dusty sources. The dusty sources without counterparts are
good candidates for high-redshift, strongly lensed submillimeter galaxies. We
derive number counts for each population from 1 Jy down to roughly 9, 5, and 11
mJy at 95, 150, and 220 GHz. We compare these counts with galaxy population
models and find that none of the models we consider for either population
provide a good fit to the measured counts in all three bands. The disparities
imply that these measurements will be an important input to the next generation
of millimeter-wave extragalactic source population models.Comment: 23 pages, 8 figures, submitted to Ap
Zoonotic Viruses Associated with Illegally Imported Wildlife Products
The global trade in wildlife has historically contributed to the emergence and spread of infectious diseases. The United States is the world's largest importer of wildlife and wildlife products, yet minimal pathogen surveillance has precluded assessment of the health risks posed by this practice. This report details the findings of a pilot project to establish surveillance methodology for zoonotic agents in confiscated wildlife products. Initial findings from samples collected at several international airports identified parts originating from nonhuman primate (NHP) and rodent species, including baboon, chimpanzee, mangabey, guenon, green monkey, cane rat and rat. Pathogen screening identified retroviruses (simian foamy virus) and/or herpesviruses (cytomegalovirus and lymphocryptovirus) in the NHP samples. These results are the first demonstration that illegal bushmeat importation into the United States could act as a conduit for pathogen spread, and suggest that implementation of disease surveillance of the wildlife trade will help facilitate prevention of disease emergence
Trust, benefit, satisfaction, and burden: A randomized controlled trial to reduce cancer risk through African-American churches
Community-based participatory research (CBPR) approaches that actively engage communities in a study are assumed to lead to relevant findings, trusting relationships, and greater satisfaction with the research process
Angular Power Spectra of the Millimeter Wavelength Background Light from Dusty Star-forming Galaxies with the South Pole Telescope
We use data from the first 100 square-degree field observed by the South Pole
Telescope (SPT) in 2008 to measure the angular power spectrum of temperature
anisotropies contributed by the background of dusty star-forming galaxies
(DSFGs) at millimeter wavelengths. From the auto and cross-correlation of 150
and 220 GHz SPT maps, we significantly detect both Poisson distributed and, for
the first time at millimeter wavelengths, clustered components of power from a
background of DSFGs. The spectral indices between 150 and 220 GHz of the
Poisson and clustered components are found to be 3.86 +- 0.23 and 3.8 +- 1.3
respectively, implying a steep scaling of the dust emissivity index beta ~ 2.
The Poisson and clustered power detected in SPT, BLAST (at 600, 860, and 1200
GHz), and Spitzer (1900 GHz) data can be understood in the context of a simple
model in which all galaxies have the same graybody spectrum with dust
emissivity index of beta = 2 and dust temperature T_d = 34 K. In this model,
half of the 150 GHz background light comes from redshifts greater than 3.2. We
also use the SPT data to place an upper limit on the amplitude of the kinetic
Sunyaev-Zel'dovich power spectrum at l = 3000 of 13 uK^2 at 95% confidence.Comment: 18 pages, 9 figure
Extragalactic millimeter-wave sources in South Pole Telescope survey data: source counts, catalog, and statistics for an 87 square-degree field
We report the results of an 87 square-degree point-source survey centered at
R.A. 5h30m, decl. -55 deg. taken with the South Pole Telescope (SPT) at 1.4 and
2.0 mm wavelengths with arc-minute resolution and milli-Jansky depth. Based on
the ratio of flux in the two bands, we separate the detected sources into two
populations, one consistent with synchrotron emission from active galactic
nuclei (AGN) and one consistent with thermal emission from dust. We present
source counts for each population from 11 to 640 mJy at 1.4 mm and from 4.4 to
800 mJy at 2.0 mm. The 2.0 mm counts are dominated by synchrotron-dominated
sources across our reported flux range; the 1.4 mm counts are dominated by
synchroton-dominated sources above ~15 mJy and by dust-dominated sources below
that flux level. We detect 141 synchrotron-dominated sources and 47
dust-dominated sources at S/N > 4.5 in at least one band. All of the most
significantly detected members of the synchrotron-dominated population are
associated with sources in previously published radio catalogs. Some of the
dust-dominated sources are associated with nearby (z << 1) galaxies whose dust
emission is also detected by the Infrared Astronomy Satellite (IRAS). However,
most of the bright, dust-dominated sources have no counterparts in any existing
catalogs. We argue that these sources represent the rarest and brightest
members of the population commonly referred to as sub-millimeter galaxies
(SMGs). Because these sources are selected at longer wavelengths than in
typical SMG surveys, they are expected to have a higher mean redshift
distribution and may provide a new window on galaxy formation in the early
universe.Comment: 35 emulateapj pages, 12 figures, 5 table
Molecular Ecology and Natural History of Simian Foamy Virus Infection in Wild-Living Chimpanzees
Identifying microbial pathogens with zoonotic potential in wild-living primates can be important to human health, as evidenced by human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2) and Ebola virus. Simian foamy viruses (SFVs) are ancient retroviruses that infect Old and New World monkeys and apes. Although not known to cause disease, these viruses are of public health interest because they have the potential to infect humans and thus provide a more general indication of zoonotic exposure risks. Surprisingly, no information exists concerning the prevalence, geographic distribution, and genetic diversity of SFVs in wild-living monkeys and apes. Here, we report the first comprehensive survey of SFVcpz infection in free-ranging chimpanzees (Pan troglodytes) using newly developed, fecal-based assays. Chimpanzee fecal samples (n = 724) were collected at 25 field sites throughout equatorial Africa and tested for SFVcpz-specific antibodies (n = 706) or viral nucleic acids (n = 392). SFVcpz infection was documented at all field sites, with prevalence rates ranging from 44% to 100%. In two habituated communities, adult chimpanzees had significantly higher SFVcpz infection rates than infants and juveniles, indicating predominantly horizontal rather than vertical transmission routes. Some chimpanzees were co-infected with simian immunodeficiency virus (SIVcpz); however, there was no evidence that SFVcpz and SIVcpz were epidemiologically linked. SFVcpz nucleic acids were recovered from 177 fecal samples, all of which contained SFVcpz RNA and not DNA. Phylogenetic analysis of partial gag (616 bp), pol-RT (717 bp), and pol-IN (425 bp) sequences identified a diverse group of viruses, which could be subdivided into four distinct SFVcpz lineages according to their chimpanzee subspecies of origin. Within these lineages, there was evidence of frequent superinfection and viral recombination. One chimpanzee was infected by a foamy virus from a Cercopithecus monkey species, indicating cross-species transmission of SFVs in the wild. These data indicate that SFVcpz (i) is widely distributed among all chimpanzee subspecies; (ii) is shed in fecal samples as viral RNA; (iii) is transmitted predominantly by horizontal routes; (iv) is prone to superinfection and recombination; (v) has co-evolved with its natural host; and (vi) represents a sensitive marker of population structure that may be useful for chimpanzee taxonomy and conservation strategies
The GuideLine Implementability Appraisal (GLIA): development of an instrument to identify obstacles to guideline implementation
BACKGROUND: Clinical practice guidelines are not uniformly successful in influencing clinicians' behaviour toward best practices. Implementability refers to a set of characteristics that predict ease of (and obstacles to) guideline implementation. Our objective is to develop and validate a tool for appraisal of implementability of clinical guidelines. METHODS: Indicators of implementability were identified from the literature and used to create items and dimensions of the GuideLine Implementability Appraisal (GLIA). GLIA consists of 31 items, arranged into 10 dimensions. Questions from 9 of the 10 dimensions are applied individually to each recommendation of the guideline. Decidability and Executability are critical dimensions. Other dimensions are Global, Presentation and Formatting, Measurable Outcomes, Apparent Validity, Flexibility, Effect on Process of Care, Novelty/Innovation, and Computability. We conducted a series of validation activities, including validation of the construct of implementability, expert review of content for clarity, relevance, and comprehensiveness, and assessment of construct validity of the instrument. Finally, GLIA was applied to a draft guideline under development by national professional societies. RESULTS: Evidence of content validity and preliminary support for construct validity were obtained. The GLIA proved to be useful in identifying barriers to implementation in the draft guideline and the guideline was revised accordingly. CONCLUSION: GLIA may be useful to guideline developers who can apply the results to remedy defects in their guidelines. Likewise, guideline implementers may use GLIA to select implementable recommendations and to devise implementation strategies that address identified barriers. By aiding the design and operationalization of highly implementable guidelines, our goal is that application of GLIA may help to improve health outcomes, but further evaluation will be required to support this potential benefit
Millimeter-wave Point Sources from the 2500-square-degree SPT-SZ Survey: Catalog and Population Statistics
We present a catalog of emissive point sources detected in the SPT-SZ survey,
a contiguous 2530-square-degree area surveyed with the South Pole Telescope
(SPT) from 2008 - 2011 in three bands centered at 95, 150, and 220 GHz. The
catalog contains 4845 sources measured at a significance of 4.5 sigma or
greater in at least one band, corresponding to detections above approximately
9.8, 5.8, and 20.4 mJy in 95, 150, and 220 GHz, respectively. Spectral behavior
in the SPT bands is used for source classification into two populations based
on the underlying physical mechanisms of compact, emissive sources that are
bright at millimeter wavelengths: synchrotron radiation from active galactic
nuclei and thermal emission from dust. The latter population includes a
component of high-redshift sources often referred to as submillimeter galaxies
(SMGs). In the relatively bright flux ranges probed by the survey, these
sources are expected to be magnified by strong gravitational lensing. The
survey also contains sources consistent with protoclusters, groups of dusty
galaxies at high redshift undergoing collapse. We cross-match the SPT-SZ
catalog with external catalogs at radio, infrared, and X-ray wavelengths and
identify available redshift information. The catalog splits into 3980
synchrotron-dominated and 865 dust-dominated sources and we determine a list of
506 SMGs. Ten sources in the catalog are identified as stars. We calculate
number counts for the full catalog, and synchrotron and dusty components, using
a bootstrap method and compare our measured counts with models. This paper
represents the third and final catalog of point sources in the SPT-SZ survey.Comment: 43 pages, 19 figures, 7 tables. Submitted to AAS Journals 03/05/2020.
03/23/2020 co-author affiliation and acknowledgments update
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