72 research outputs found
A Survey of the Student Attitudes Toward Woodworking Technology at F. E. Kellam High School
The problems of this study was to determine the reason or reasons behind the selection of woods technology by those students who were fulfilling an elective course credit at Kellam High School. Among those ideas that were being examined were 1) the student\u27s attraction to the material and the product that results from the material; 2) other influences such as parents, peers, and school counselors; 3) to what degree does occupational or vocational intent interest the student
Awareness, interest, and preferences of primary care providers in using point-of-care cancer screening technology
Well-developed point-of-care (POC) cancer screening tools have the potential to provide better cancer care to patients in both developed and developing countries. However, new medical technology will not be adopted by medical providers unless it addresses a population’s existing needs and end-users’ preferences. The goals of our study were to assess primary care providers’ level of awareness, interest, and preferences in using POC cancer screening technology in their practice and to provide guidelines to biomedical engineers for future POC technology development. A total of 350 primary care providers completed a one-time self-administered online survey, which took approximately 10 minutes to complete. A $50 Amazon gift card was given as an honorarium for the first 100 respondents to encourage participation. The description of POC cancer screening technology was provided in the beginning of the survey to ensure all participants had a basic understanding of what constitutes POC technology. More than half of the participants (57%) stated that they heard of the term “POC technology” for the first time when they took the survey. However, almost all of the participants (97%) stated they were either “very interested” (68%) or “somewhat interested” (29%) in using POC cancer screening technology in their practice. Demographic characteristics such as the length of being in the practice of medicine, the percentage of patients on Medicaid, and the average number of patients per day were not shown to be associated with the level of interest in using POC. These data show that there is a great interest in POC cancer screening technology utilization among this population of primary care providers and vast room for future investigations to further understand the interest and preferences in using POC cancer technology in practice. Ensuring that the benefits of new technology outweigh the costs will maximize the likelihood it will be used by medical providers and patients
HD 209621: Abundances of neutron-capture elements
High resolution spectra obtained from the Subaru Telescope High Dispersion
Spectrograph have been used to update the stellar atmospheric parameters and
metallicity of the star HD 209621. We have derived a metallicity of [Fe/H] =
-1.93 for this star, and have found a large enhancement of carbon and of heavy
elements, with respect to iron. Updates on the elemental abundances of four
s-process elements (Y, Ce, Pr, Nd) along with the first estimates of abundances
for a number of other heavy elements (Sr, Zr, Ba, La, Sm, Eu, Er, Pb) are
reported. The stellar atmospheric parameters, the effective temperature, Teff,
and the surface gravity, log g (4500 K, 2.0), are determined from LTE analysis
using model atmospheres. Estimated [Ba/Eu] = +0.35, places the star in the
group of CEMP-(r+s) stars; however, the s-elements abundance pattern seen in HD
209621 is characteristic of CH stars; notably, the 2nd-peak s-process elements
are more enhanced than the first peak s-process elements. HD 209621 is also
found to show a large enhancement of the 3rd-peak s-process element lead (Pb)
with [Pb/Fe] = +1.88. The relative contributions of the two neutron-capture
processes, r- and s- to the observed abundances are examined using a parametric
model based analysis, that hints that the neutron-capture elements in HD 209621
primarily originate in s-process.Comment: 16 pages,8 figures. Accepted for publication in MNRA
Abundance analysis of cool extreme helium star: LSS 3378
Abundance analysis of the cool extreme helium (EHe) star LSS 3378 is
presented. The abundance analysis is done using LTE line formation and LTE
model atmospheres constructed for EHe stars.
The atmosphere of LSS 3378 shows evidence of H-burning, He-burning, and
s-process nucleosynthesis. The derived abundances of iron-peak and
alpha-elements indicate absence of selective fractionation or any other
processes that can distort chemical composition of these elements. Hence, the
Fe abundance (log epsilon(Fe) = 6.1) is adopted as an initial metallicity
indicator. The measured abundances of LSS 3378 are compared with those of R
Coronae Borealis (RCB) stars and with rest of the EHe stars as a group.Comment: 7 pages, 4 figures, 3 tables, MNRAS format, accepted for publication
in MNRA
Abundances of Post-Iron-Peak Elements in HD 35155: A Symbiotic Star of Spectral Type S
We present abundances of Ti, Fe, and Ni as well as 10 post-iron-peak elements in the extrinsic, Galactic S star HD 35155. This star is of interest because it shows many characteristics of symbiotic stars and displays the same pattern of abundance enhancements observed in yellow symbiotic stars. It is clear that HD 35155 is associated with the symbiotic stars and provides an important link between the symbiotic phenomena and chemically peculiar stars. In addition, the abundance ratio of heavy to light s-process elements correlates with the metallicity of HD 35155, as is expected if the 13C neutron source drives the s-process. Our models predict that the abundance of lead should be enhanced by a factor of between 50 to 500 in HD 35155
HE 1015-2050: Discovery of a Hydrogen-deficient carbon star at high galactic latitude
Medium resolution spectral analysis of candidate Faint High Latitude Carbon
(FHLC) stars from Hamburg/ESO survey has given us the potential to discover
objects of rare types. Two primary spectral characteristics of R Coroanae
Borealis (RCB) stars are hydrogen deficiency and weaker CN bands relative to
C_{2} bands. They are also characterized by their characteristic location in
the J-H, H-K plane with respect to cool carbon stars. From a spectral analysis
of a sample of 243 candidate FHLC stars, we have discovered a
hydrogen-deficient carbon (HdC) star HE 1015-2050, at high Galactic latitude. A
differential analysis of its spectrum with that of the spectrum of U Aquarii (U
Aqr), a well-known cool HdC star of RCB type, provides sufficient evidence to
put this object in a group same as that of U Aqr. Further, it is shown that HE
1015-2050 does not belong to any of the C-star groups CH, C-R, C-N or C-J. Cool
RCB stars form a group of relatively rare astrophysical objects; approximately
51 are known in the Galaxy and some 18 in the Large Magellanic Clouds (LMC) and
five in Small Magellanic Cloud (SMC). The present discovery adds a new member
to this rare group. Although its spectral characteristics and its location in
the J-H vs H-K plane places HE 1015-2050 in the same group to which U Aqr
belongs, extended photometric observations would be useful to learn if there is
any sudden decline in brightness, this being a characteristic property of HdC
stars of RCB type.Comment: 5 pages,3 figure
More lead stars
The standard model for the operation of the s-process in asymptotic giant
branch (AGB) stars predicts that low-metallicity ([Fe/H] <= -1) AGB stars
should exhibit large overabundances of Pb and Bi as compared to other
s-elements. Eight CH stars (with [Fe/H] ranging from -1.5 to -2.5) are studied
in the present paper using high-resolution spectra (R = lambda/Delta lambda =
135 000), and five of them appear to be enriched in lead (with [Pb/Ce] ~ 0.7).
Abundances of heavy elements in these `lead stars' (defined as stars enriched
in s-elements and with [Pb/hs] >= 1, hs being any of Ba, La or Ce) are
consistent with the predictions for the s-process operating in low-metallicity
AGB stars as a consequence of the `partial mixing' of protons below the
convective hydrogen envelope. Two among the studied stars (HD 189711 and V Ari)
add to a growing number of low-metallicity stars which do not conform to these
predictions, however. Variations on the canonical proton-mixing scenario for
the operation of the s-process in low-metallicity stars, that could account for
these discrepant stars, are briefly discussed.Comment: 9 pages, 6 figures, accepted for publication in Astronomy &
Astrophysics. Also available at http://www-astro.ulb.ac.be/Html/ps.html#PR
Abundances of neutron-capture elements in G 24-25. A halo-population CH subgiant
The differences between the neutron-capture element abundances of halo stars
are important to our understanding of the nucleosynthesis of elements heavier
than the iron group. We present a detailed abundance analysis of carbon and
twelve neutron-capture elements from Sr up to Pb for a peculiar halo star
G24-25 with [Fe/H] = -1.4 in order to probe its origin. The equivalent widths
of unblended lines are measured from high resolution NOT/FIES spectra and used
to derive abundances based on Kurucz model atmospheres. In the case of CH, Pr,
Eu, Gd, and Pb lines, the abundances are derived by fitting synthetic profiles
to the observed spectra. Abundance analyses are performed both relative to the
Sun and to a normal halo star G16-20 that has similar stellar parameters as
G24-25. We find that G24-25 is a halo subgiant star with an unseen component.
It has large overabundances of carbon and heavy s-process elements and mild
overabundances of Eu and light s-process elements. This abundance distribution
is consistent with that of a typical CH giant. The abundance pattern can be
explained by mass transfer from a former asymptotic giant branch component,
which is now a white dwarf.Comment: 11 pages, 9 figures, accepted for publication in A&
Correlation between technetium and lithium in a sample of oxygen-rich AGB variables
The aims of this paper are: 1) to revisit the Tc content of a sample of
oxygen-rich asymptotic giant branch (AGB) variables and 2) to increase the
number of such stars for which the Li abundance has been measured to provide
constraints on theoretical models of extra-mixing processes. To this end, we
analysed high-resolution spectra of 18 sample stars for the presence of
absorption lines of Tc and Li. The abundance of the latter was determined by
comparing the observed spectra to hydrostatic MARCS model spectra. Bolometric
magnitudes were established from near-IR photometry and pulsation periods. We
reclassify the star V441 Cyg as Tc-rich, and the unusual Mira star R Hya, as
well as W Eri, as Tc-poor. The abundance of Li, or an upper limit to it, was
determined for all of the sample stars. In all stars with Tc we also detected
Li. Most of them have a Li content slightly below the solar photospheric value,
except for V441 Cyg, which has ~1000 times the solar abundance. We also found
that, similar to Tc, a lower luminosity limit seems to exist for the presence
of Li. We conclude that the higher Li abundance found in the cooler and higher
luminosity objects could stem from a Li production mechanism operating on the
AGB. The stellar mass might have a crucial influence on this (extra-mixing)
production mechanism. It was speculated that the declining pulsation period of
R Hya is caused by a recent thermal pulse (TP). While not detecting Tc does not
rule out a TP, it indicates that the TPs are not strong enough to drive
dredge-up in R Hya. V441 Cyg, on the other hand, could either be a low-mass,
intrinsic S-star that produced its large amount of Li by extra-mixing
processes, or an intermediate-mass star (M>=M_sun) undergoing Li production due
to hot bottom burning.Comment: 12 pages, 7 figures, accepted for publication in A&
Near-Infrared photometry and spectroscopy of NGC 6539 and UKS 1: two intermediate metallicity Bulge Globular Clusters
Using the SofI imager at ESO/NTT and NIRSPEC spectrograph at KeckII, we have
obtained J,K images and echelle spectra covering the range 1.5 - 1.8 micron for
the intermediate metallicity Bulge globular clusters NGC6539 and UKS1. We find
[Fe/H]=-0.76 and -0.78, respectively, and an average alpha-enhancement of +0.44
dex and +0.31 dex, consistent with previous measurements of metal rich Bulge
clusters, and favoring the scenario of rapid chemical enrichment. We also
measure very low 12C/13C=4.5 +/-1 isotopic ratios in both clusters, suggesting
that extra-mixing mechanisms due to cool bottom processing are at work during
the evolution along the Red Giant Branch. Finally, we measure accurate radial
velocities of =+31 +/-4Km/s and =+57 +/-6Km/s and velocity dispersion
of about 8 Km/s and 11 Km/s for NGC6539 and UKS1, respectively.Comment: 10 pages, 7 figures, accepted for publication at MNRA
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