2,448 research outputs found
A differential chemical abundance scale for the globular cluster M5
We present LTE chemical abundances for five red giants and one AGB star in
the Galactic globular cluster (GC) M5 based on high resolution spectroscopy
using the MIKE spectrograph on the Magellan 6.5-m Clay telescope. Our results
are based on a line-by-line differential abundance analysis relative to the
well-studied red giant Arcturus. The stars in our sample that overlap with
existing studies in the literature are consistent with published values for
[Fe/H] and agree to within typically 0.04 dex for the alpha-elements. Most
deviations can be assigned to varying analysis techniques in the literature.
This strengthens our newly established differential GC abundance scale and
advocates future use of this method. In particular, we confirm a mean [Fe I/H]
of -1.33 +- 0.03 (stat.) +- 0.03 (sys.) dex and also reproduce M5's enhancement
in the alpha-elements (O,Mg,Si,Ca,Ti) at +0.4 dex, rendering M5 a typical
representative of the Galactic halo. Over-ionization of Fe I in the atmospheres
of these stars by non-LTE effects is found to be less than 0.07 dex. Five of
our six stars show O-Na-Al-Mg abundance patterns consistent with pollution by
proton-capture nucleosynthesis products.Comment: 12 pages, 7 figures, accepted for publication in the A
Technology survey of computer software as applicable to the MIUS project
Existing computer software, available from either governmental or private sources, applicable to modular integrated utility system program simulation is surveyed. Several programs and subprograms are described to provide a consolidated reference, and a bibliography is included. The report covers the two broad areas of design simulation and system simulation
Alpha Enhancement and the Metallicity Distribution Function of Plaut's Window
We present Fe, Si, and Ca abundances for 61 giants in Plaut's Window
(l=-1,b=-8.5) and Fe abundances for an additional 31 giants in a second, nearby
field (l=0,b=-8) derived from high resolution (R~25,000) spectra obtained with
the Blanco 4m telescope and Hydra multifiber spectrograph. The median
metallicity of red giant branch (RGB) stars in the Plaut field is ~0.4 dex
lower than those in Baade's Window, and confirms the presence of an iron
abundance gradient along the bulge minor axis. The full metallicity range of
our (biased) RGB sample spans -1.5<[Fe/H]<+0.3, which is similar to that found
in other bulge fields. We also derive a photometric metallicity distribution
function for RGB stars in the (l=-1,b=-8.5) field and find very good agreement
with the spectroscopic metallicity distribution. The radial velocity and
dispersion data for the bulge RGB stars are in agreement with previous results
of the BRAVA survey, and we find evidence for a decreasing velocity dispersion
with increasing [Fe/H]. The [alpha/Fe] enhancement in Plaut field stars is
nearly identical to that observed in Baade's window, and suggests that an
[alpha/Fe] gradient does not exist between b=-4 and -8. Additionally, a subset
of our sample (23 stars) appear to be foreground red clump stars that are very
metal--rich, exhibit small metallicity and radial velocity dispersions, and are
enhanced in alpha elements. While these stars likely belong to the Galactic
inner disk population, they exhibit [alpha/Fe] ratios that are enhanced above
the thin and thick disk.Comment: Accepted for publication in ApJ. 38 pages, 11 figures, and 2 tables.
Requests for higher resolution figures and electronic versions of tables 1
and/or 2 in advance of publication may be sent to cijohnson[at]astro.ucla.ed
On the Augmentation of Cognitive Accuracy and Cognitive Precision in Human/Cog Ensembles
Whenever humans use tools human performance is enhanced. Cognitive systems
are a new kind of tool continually increasing in cognitive capability and are
now performing high level cognitive tasks previously thought to be explicitly
human. Usage of such tools, known as cogs, are expected to result in ever
increasing levels of human cognitive augmentation. In a human cog ensemble, a
cooperative, peer to peer, and collaborative dialog between a human and a
cognitive system, human cognitive capability is augmented as a result of the
interaction. The human cog ensemble is therefore able to achieve more than just
the human or the cog working alone. This article presents results from two
studies designed to measure the effect information supplied by a cog has on
cognitive accuracy, the ability to produce the correct result, and cognitive
precision, the propensity to produce only the correct result. Both cognitive
accuracy and cognitive precision are shown to be increased by information of
different types (policies and rules, examples, and suggestions) and with
different kinds of problems (inventive problem solving and puzzles). Similar
effects shown in other studies are compared.Comment: 12 pages, 7 figures, 4 table
Structural Racism and Youth Development
Youth of color have experienced poor outcomes relative to their white counterparts historically, and these disparities persist today. Researchers have offered a number of explanations for these disparities, some of the more popular of which have focused on individual deficiencies. If one elucidates the underlying theories of change of dominant practices and public policies in the youth field, it appears that, despite variation in approach and emphasis, they too have focused on individual behavior. While behavior is clearly an important contributor to the outcomes that individuals experience, it is not the sole determinant. Rather, we contend that there are larger, structural factors that contribute to the racial disparities between youth of color and their white counterparts that deserve systematic and sustained attention
Review of Cardiotoxicity in Pediatric Cancer Patients: During and after Therapy
With the improvement in survival from childhood cancer, late effects of therapy are becoming more apparent. Cardiac disease, one of these late effects, has a significant impact on the life of survivors of childhood cancers. Most survivors are followed by primary care doctors and adult subspecialists after they have graduated from pediatric centers. Since much of the cardiac toxicity of therapy occurs years off of therapy, it is important for these physicians to be aware of how to monitor survivors for the development of cardiac toxicities. In this paper we will discuss the incidence of cardiac disease during treatment and in survivors, what treatment modalities contribute to its development and modalities utilized to screen for cardiac disease. Recommendations for posttherapy monitoring will be emphasized
Low altitude temperature and humidity profile data for application to aircraft noise propagation
A data search of the weather statistics from 11 widely dispersed geographical locations within the continental United States was conducted. The sites, located long both sea-coasts and in the interior, span the northern, southern, and middle latitudes. The weather statistics, retrieved from the records of these 11 sites, consist of two daily observations taken over a 10-year period. The data were sorted with respect to precipitation and surface winds and classified into temperature intervals of 5 C and relative humidity intervals of 10 percent for the lower 1400 meters of the atmosphere. These data were assembled in a statistical format and further classified into altitude increments of 200 meters. The data are presented as sets of tables for each site by season of the year and include both daily observations
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