830 research outputs found
Informatics Metrics and Measures for a Smart Public Health Systems Approach: Information Science Perspective
Public health informatics is an evolving domain in which practices constantly change to meet the demands of a highly complex public health and healthcare delivery system. Given the emergence of various concepts, such as learning health systems, smart health systems, and adaptive complex health systems, health informatics professionals would benefit from a common set of measures and capabilities to inform our modeling, measuring, and managing of health system “smartness.” Here, we introduce the concepts of organizational complexity, problem/issue complexity, and situational awareness as three codependent drivers of smart public health systems characteristics. We also propose seven smart public health systems measures and capabilities that are important in a public health informatics professional’s toolkit
Lithostratigraphy, sedimentation and evolution of the Volta Basin in Ghana
We present a revised lithostratigraphy for the Voltaian Supergroup of Ghana, based on a review of existing literature, interpretations of remotely sensed data and reconnaissance field survey of the Volta Basin. These strata thicken eastwards, to a maximum of between 5 and 6 km adjacent to the Pan-African Dahomeyide orogen. They began to accumulate some time after about 1000 Ma, along the margin of an epicontinental sea. Initial sedimentation, comprising the age-equivalent Kwahu and Bombouaka Groups, shows a cyclical mode of deposition controlled by eustatic changes in sea-level that produced a range of nearshore marine, littoral and terrestrial environments.
A major erosional interval was followed by deposition of the 3–4 km thick Oti-Pendjari Group. Basal tillites and associated sandy diamictons are correlated with the Marinoan (end-Cryogenian) glaciation, indicating a maximum depositional age of about 635 Ma. The overlying cap carbonates and tuffs were deposited within a shallow epeiric sea bordered by a volcanically active rift system. The main part of the group records the transition from a rifted passive margin to a fully developed foreland basin receiving marine flysch in the form of argillaceous strata interbedded with highly immature wacke-type sandstones and conglomerates. Maximum accommodation space was developed within a foredeep adjacent to the Dahomeyide belt. Towards the end of the orogenic phase, the foredeep succession became partially inverted and then was buried under coarse terrestrial, red-bed molasse of the Obosum Group
Willingness To Donate Blood During the Summer
Introduction. Each year donation rates fall in the summer months straining blood banks’ capacities to meet local demands. In hopes of identifying factors to increase summer donations, our study investigated donor reported barriers which influence summer donations habits.Methods. An anonymous 16 question survey investigating various donation factors was administered across multiple American Red Cross (ARC) donation centers in Vermont. Questions addressed donor demographics, frequency of blood donation, preference in appointment making modalities including smartphone app use, summer travel habits, willingness to donate during vacation, and factors that deter donors from donating on vacation.Results. A total of 292 surveys were received. Survey respondents across multiple demographic groups cited similar barriers to summer donation, namely “Too busy” (27.5 %) and “Traveling is a time for me to relax.” (30.6 %). Of the respondents who travel in the summer, very few reported donating while traveling (3.4 %). Summer donation rates between summertime travelers (36.5 %) and non-travelers (36.4 %) were essentially equivalent. The most preferred methods of scheduling appointments were via ARC website (45.6 %) and phone (28.4%). Willingness to use the ARC app was highest among respondents ages of 18 to 34 (45-55%) and lowest among ages 55 and older (13-15%). Of respondents with no prior knowledge of summer seasonal shortages (22 %), 2/3rds indicated newfound motivation to donate.Conclusion. Regardless of travel, increasing awareness of summer shortages may increase summer donations. Use of donor websites and smartphone apps may be instrumented as part of recruitment efforts.https://scholarworks.uvm.edu/comphp_gallery/1239/thumbnail.jp
Black Hole Genealogy: Identifying Hierarchical Mergers with Gravitational Waves
In dense stellar environments, the merger products of binary black hole mergers may undergo additional mergers. These hierarchical mergers are naturally expected to have higher masses than the first generation of black holes made from stars. The components of hierarchical mergers are expected to have significant characteristic spins, imprinted by the orbital angular momentum of the previous mergers. However, since the population properties of first-generation black holes are uncertain, it is difficult to know if any given merger is first-generation or hierarchical. We use observations of gravitational waves to reconstruct the binary black hole mass and spin spectrum of a population including the possibility of hierarchical mergers. We employ a phenomenological model that captures the properties of merging binary black holes from simulations of globular clusters. Inspired by recent work on the formation of low-spin black holes, we include a zero-spin subpopulation. We analyze binary black holes from LIGO and Virgo's first two observing runs, and find that this catalog is consistent with having no hierarchical mergers. We find that the most massive system in this catalog, GW170729, is mostly likely a first-generation merger, having a 4% probability of being a hierarchical merger assuming a 5 × 10⁵ M_⊙ globular cluster mass. Using our model, we find that 99% of first-generation black holes in coalescing binaries have masses below 44 M_⊙, and the fraction of binaries with near-zero component spins is less than 0.16 (90% probability). Upcoming observations will determine if hierarchical mergers are a common source of gravitational waves
Chemical Substructure in the Milky Way Halo: A New Population of Old Stars
We report the results of a coherent study of a new class of halo stars defined on the basis of the chemical compositions of three metal-poor objects ([Fe/H] -2) that exhibit unusually low abundances of α-element (Mg, Si, Ca) and neutron-capture (Sr, Y, Ba) material. Our analyses confirm and expand on earlier reports of atypical α- and neutron-capture abundances in BD +80°245, G4-36, and CS 22966-043. We also find that the latter two stars exhibit unusual relative abundance enhancements within the iron peak (Cr, Mn, Ni, Zn), along with what may be large abundances of Ga, an element not previously reported as being observed in any metal-poor star. These results provide further evidence that chemical enrichment and star formation histories varied from region to region within the Milky Way halo. Comparing the chemical abundances of the newly identified stellar population to supernova model yields, we derive supernova ratios of Type Ia versus Type II events in the range of 0.6 (NIa/NII)New Pop 1.3. For the Sun, we derive 0.18 ± 0.01 < (NIa/NII)☉ < 0.25 ± 0.06, supernova ratios in good agreement with values found in the literature. Given the relatively low metallicity and relatively high NIa/NII ratios of the low-α stars studied here, these objects may have been born from material produced in the yields of the earliest Type Ia supernova events. We also report the results of a preliminary attempt to employ the observed chemical abundances of low-metallicity stars in the identification, and possible cosmic evolution, of Type Ia supernova progenitors, and we discuss the limitations of current model yields
Teologija na tržištu
One task intended to measure sensitivity to temporal fine structure (TFS) involves the discrimination of a harmonic complex tone from a tone in which all harmonics are shifted upwards by the same amount in hertz. Both tones are passed through a fixed bandpass filter centered on the high harmonics to reduce the availability of excitation-pattern cues and a background noise is used to mask combination tones. The role of frequency selectivity in this "TFS1" task was investigated by varying level. Experiment 1 showed that listeners performed more poorly at a high level than at a low level. Experiment 2 included intermediate levels and showed that performance deteriorated for levels above about 57 dB sound pressure level. Experiment 3 estimated the magnitude of excitation-pattern cues from the variation in forward masking of a pure tone as a function of frequency shift in the complex tones. There was negligible variation, except for the lowest level used. The results indicate that the changes in excitation level at threshold for the TFS1 task would be too small to be usable. The results are consistent with the TFS1 task being performed using TFS cues, and with frequency selectivity having an indirect effect on performance via its influence on TFS cues. (C) 2015 Acoustical Society of America
Evidence for hierarchical black hole mergers in the second LIGO--Virgo gravitational-wave catalog
We study the population properties of merging binary black holes in the
second LIGO--Virgo Gravitational-Wave Transient Catalog assuming they were all
formed dynamically in gravitationally bound clusters. Using a phenomenological
population model, we infer the mass and spin distribution of first-generation
black holes, while self-consistently accounting for hierarchical mergers.
Considering a range of cluster masses, we see compelling evidence for
hierarchical mergers in clusters with escape velocities . For our most probable cluster mass, we find that the
catalog contains at least one second-generation merger with credibility.
We find that the hierarchical model is preferred over an alternative model with
no hierarchical mergers (Bayes factor ) and that GW190521
is favored to contain two second-generation black holes with odds
, and GW190519, GW190602, GW190620, and GW190706 are
mixed-generation binaries with . However, our results depend
strongly on the cluster escape velocity, with more modest evidence for
hierarchical mergers when the escape velocity is . Assuming that all binary black holes are formed
dynamically in globular clusters with escape velocities on the order of tens of
, GW190519 and GW190521 are favored to include a
second-generation black hole with odds . In this case, we find
that of black holes from the inferred total population have masses that
are less than , and that this constraint is robust to our choice
of prior on the maximum black hole mass.Comment: 15 pages, 11 figures, 1 appendi
Characterizing the Chemistry of the Milky Way Stellar Halo: Detailed Chemical Analysis of a Metal-Poor Stellar Stream
We present the results of a detailed abundance analysis of one of the
confirmed building blocks of the Milky Way stellar halo, a
kinematically-coherent metal-poor stellar stream. We have obtained high
resolution and high S/N spectra of 12 probable stream members using the MIKE
spectrograph on the Magellan-Clay Telescope at Las Campanas Observatory and the
2dCoude spectrograph on the Smith Telescope at McDonald Observatory. We have
derived abundances or upper limits for 51 species of 46 elements in each of
these stars. The stream members show a range of metallicity (-3.4 < [Fe/H] <
-1.5) but are otherwise chemically homogeneous, with the same star-to-star
dispersion in [X/Fe] as the rest of the halo. This implies that, in principle,
a significant fraction of the Milky Way stellar halo could have formed from
accreted systems like the stream. The stream stars show minimal evolution in
the alpha or Fe-group elements over the range of metallicity. This stream is
enriched with material produced by the main and weak components of the rapid
neutron-capture process and shows no evidence for enrichment by the slow
neutron-capture process.Comment: v2: Removed references to M15 after learning that the source
kinematic data for M15 were incorrect in an earlier paper. M15 is not related
to this stream. (ApJ, accepted; 31 pages, 18 figures, 11 tables
Volume 11
Table of Contents:
Introduction, Dr. Roger A. Byrne, Dean
From the Editor, Dr. Larissa Kat Tracy
From the Designers, Rachel English, Rachel Hanson
Synthesis of 3,5-substituted Parabens and their Antimicrobial Properties, Jacob Coarney, Ryan White
Chernobyl: Putting Perestroika and Glasnot to the Test, Joseph Hyman
Art by Jenny Raven
Watering Down Accessibility: The Issue with Public Access to Alaska\u27s Federal Waterways, Meagan Garrett
Why Has the Democratic Republic of the Congo outsourced its Responsibility to Educate its Citizens? Ibrahim Kante
Art by Summer Meinhard
A Computational Study of Single Molecule Diodes, Lauren Johnson
Satire of the State through Discourse: Applying Althusser and Bakhtin, William Dean Howells Editha , Glen Spencer
Design by Laura Gottschalk
Why did the United Kingdom Vote to Leave the European Union?, Christopher Siefke
Art by Pink Powell
Art by Natasha Woodmany
Method of Detection of PFOA in Water Samples, Katharine Colley
Art by Abbey Mays
The Rhetorical Construction of eSports\u27 Legitimacy, Charlotte Pott
The SEGUE Stellar Parameter Pipeline. III. Comparison with High-Resolution Spectroscopy of SDSS/SEGUE Field Stars
We report high-resolution spectroscopy of 125 field stars previously observed
as part of the Sloan Digital Sky Survey and its program for Galactic studies,
the Sloan Extension for Galactic Understanding and Exploration (SEGUE). These
spectra are used to measure radial velocities and to derive atmospheric
parameters, which we compare with those reported by the SEGUE Stellar Parameter
Pipeline (SSPP). The SSPP obtains estimates of these quantities based on SDSS
ugriz photometry and low-resolution (R = 2000) spectroscopy. For F- and G-type
stars observed with high signal-to-noise ratios (S/N), we empirically determine
the typical random uncertainties in the radial velocities, effective
temperatures, surface gravities, and metallicities delivered by the SSPP to be
2.4 km/s, 130 K (2.2%), 0.21 dex, and 0.11 dex, respectively, with systematic
uncertainties of a similar magnitude in the effective temperatures and
metallicities. We estimate random errors for lower S/N spectra based on
numerical simulations.Comment: 37 pages, 6 tables, 6 figures, submitted to the Astronomical Journa
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