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INCREASING STEM PARTICIPATION AND STUDENT SUCCESS OF DEVELOPMENTAL MATHEMATICS STUDENTS AT AN URBAN COMMUNITY COLLEGE
This mixed method, quantitative and qualitative, study explores the effects of a curriculum with an emphasis on scientific, technological, and engineering focused problems and careers on student success and interest in Science, Technology, Engineering, and Mathematics (STEM). The setting is an urban community college where in the spring of 2016, 71% of the students tested into developmental mathematics (STCC, 2017).
The course of study was Algebra one, a developmental, non-college credit bearing, mathematics course. Students had the option of two paths for the subsequent course, a terminal college level mathematics class, or a STEM pathway developmental algebra two course. Pass rates, pre/posttests, pre/post interest surveys, and subsequent math course were recorded and analyzed. Furthermore, implications and limitations of the study were examined with recommendations for future research presented. The findings were that there was an increase in both path rates, and STEM interest
Sulphur in the Sculptor dwarf spheroidal galaxy - Including NLTE corrections
In Galactic halo stars, sulphur has been shown to behave like other
-elements, but until now, no comprehensive studies have been done on
this element in stars of other galaxies. Here, we use high-resolution ESO
VLT/FLAMES/GIRAFFE spectra to determine sulphur abundances for 85 stars in the
Sculptor dwarf spheroidal galaxy, covering the metallicity range . The abundances are derived from the S~I triplet at
9213, 9228, and 9238~\AA. These lines have been shown to be sensitive to
departure from local thermodynamic equilibrium, i.e. NLTE effects. Therefore,
we present new NLTE corrections for a grid of stellar parameters covering those
of the target stars. The NLTE-corrected sulphur abundances in Sculptor show the
same behaviour as other -elements in that galaxy (such as Mg, Si, and
Ca). At lower metallicities () the abundances are
consistent with a plateau at , similar to what is
observed in the Galactic halo, . With increasing
[Fe/H], the [S/Fe] ratio declines, reaching negative values at
. The sample also shows an increase in [S/Mg] with
[Fe/H], most probably because of enrichment from Type Ia supernovae.Comment: 9 pages, 11 figures, 2 tables + 3 online tables, accepted in A&
Nucleosynthesis And The Inhomogeneous Chemical Evolution Of The Carina Dwarf Galaxy
The detailed abundances of 23 chemical elements in nine bright red giant branch stars in the Carina dwarf spheroidal galaxy are presented based on high-resolution spectra gathered at the Very Large Telescope (VLT) and Magellan telescopes. A spherical model atmospheres analysis is applied using standard methods (local thermodynamic equilibrium and plane-parallel radiative transfer) to spectra ranging from 380 to 680 nm. Stellar parameters are found to be consistent between photometric and spectroscopic analyses, both at moderate and high resolution. The stars in this analysis range in metallicity from -2.9 < [Fe/H] < -1.3, and adopting the ages determined by Lemasle et al., we are able to examine the chemical evolution of Carina's old and intermediate-aged populations. One of the main results from this work is the evidence for inhomogeneous mixing in Carina and therefore for a poor statistical sampling of the supernova contributions when forming stars; a large dispersion in [Mg/Fe] indicates poor mixing in the old population, an offset in the [alpha/Fe] ratios between the old and intermediate-aged populations (when examined with previously published results) suggests that the second star formation event occurred in alpha-enriched gas, and one star, Car-612, seems to have formed in a pocket enhanced in SN Ia/II products. This latter star provides the first direct link between the formation of stars with enhanced SN Ia/II ratios in dwarf galaxies to those found in the outer Galactic halo (Ivans et al.). Another important result is the potential evidence for SNII driven winds. We show that the very metal-poor stars in Carina have not been enhanced in asymptotic giant branch or SN Ia products, and therefore their very low ratios of [Sr/Ba] suggests the loss of contributions from the early SNe II. Low ratios of [Na/Fe], [Mn/Fe], and [Cr/Fe] in two of these stars support this scenario, with additional evidence from the low [Zn/Fe] upper limit for one star. It is interesting that the chemistry of the metal-poor stars in Carina is not similar to those in the Galaxy, most of the other dwarf spheroidal galaxies, or the ultra faint dwarfs, and suggests that Carina may be at the critical mass where some chemical enrichments are lost through SN II driven winds.NSERCNSF AST 99-84073McDonald Observator
Belonging: A Phenomenological Study of Systemic Racism Experienced Among Black Students in Occupational Therapy Programs
Belonging, a crucial aspect of humanity and justice, is negated by racism. Formal analyses have shown that racial and ethnic minorities experience significantly higher rates of racial discrimination, with the greatest disparity being among Blacks. Incidences of racism toward healthcare professionals of color indicate that comprehensive and unbiased academic content is warranted in occupational therapy education. This study explored the lived experiences of systemic racism among Black occupational therapy students and their preparation to deal with racism and bias within didactic and clinical settings. This study featured a phenomenological design with data collection through semi-structured interviews and focus groups. Transcripts were coded and inductively analyzed using Qualitative Data Analysis (QDA) Miner software, and intercoder agreement was established. Themes were organized using Wilcock\u27s Occupational Perspective of Health (OPH) framework (Doing, Being, Becoming, and Belonging). The results revealed that the prevailing themes that emerged were Anxiety from Lack of Black Representation, Education through Lived Experience, including family, media, and self-education, and Initiating Change as the Diversity Person. Participants’ sense of Belonging was most affected of all the constructs in the OPH. In conclusion, the tapestry of occupational therapy curricula may benefit from incorporating explicit threads addressing the lasting effects of historic and current systemic racism, thus severely limiting students’ awareness and comprehension of occupational injustices. Recommendations are outlined to identify gaps in current occupational therapy curricula and to guide occupational therapy administrators (Chairs/Program Directors) in developing programs that acknowledge, educate, and combat the effects of systemic racism, thereby enhancing the sense of belonging for all
Oxygen Abundance in the Template Halo Giant HD 122563
HD 122563 is a well-known bright (V ¼ 6:2) halo giant of low metallicity ((Fe/H ��� 2:7). We have observed HD 122563 for infrared OH lines at 1.5-1.7 lm in the H band with the NIRSPEC high-resolution spectrograph at the 10 m Keck Telescope. Optical spectra were obtained with the UVES spectrograph at the 8 m VLT UT2 telescope at ESO (Paranal) and the FEROS spectrograph at ESO (La Silla). Based on the opti- cal high-resolution data, a detailed analysis has been carried out, and data on the forbidden (O i) 6300 Aline, unblended by telluric or sky lines, was obtained with the FEROS spectrograph. Signal-to-noise ratios of 200- 400 were obtained at resolutions of 37,000 in the H band and 45,000 in the optical. For the analysis we have adopted a photometric effective temperature Teff ¼ 4600 K. Two values for the gravity were adopted: a value deduced from ionization equilibrium, log g ¼ 1:1, with corresponding metallicity (Fe/H �¼� 2:8 and micro- turbulence velocity vt ¼ 2: 0k m s � 1 ; and log g ¼ 1:5, derived from the Hipparcos parallax, implying (Fe/H �¼� 2:71 and vt ¼ 2: 0k m s � 1 . The forbidden (O i) 6300 Aand the permitted O i 7771 Alines give O/Fe ratios essentially insensitive to model parameter variations, whereas the oxygen abundances from OH lines are sensitive to gravity, giving (O/Fe �¼þ 0:9 and +0.7, respectively, for log g ¼ 1:1 and 1.5. We derive the following oxygen abundances: for model 1, (O/Fe �¼þ 0:6, +1.1, and +0.9; and for model 2, (O/Fe �¼þ 0:6, +1.1, and +0.7, based on the (O i) 6300 A ˚ ,O i 7771 A ˚ , and IR OH 1.6 lm lines, respectively. The different oxygen abundance indicators give different oxygen abundances, illustrating the problem of oxy- gen abundance derivation in metal-poor giants. This is important because the age of globular clusters and the production of Li, Be, and B from spallation of C, N, and O atoms in the early Galaxy depend on the oxygen abundance adopted for the metal-poor stars. Subject headings: stars: abundances — stars: individual (HD 122563) — stars: Population II On-line material: machine-readable tabl
Coronary-artery bypass surgery in patients with ischemic cardiomyopathy
BACKGROUND
The survival benefit of a strategy of coronary-artery bypass grafting (CABG) added to
guideline-directed medical therapy, as compared with medical therapy alone, in patients
with coronary artery disease, heart failure, and severe left ventricular systolic
dysfunction remains unclear.
METHODS
From July 2002 to May 2007, a total of 1212 patients with an ejection fraction of 35%
or less and coronary artery disease amenable to CABG were randomly assigned to
undergo CABG plus medical therapy (CABG group, 610 patients) or medical therapy
alone (medical-therapy group, 602 patients). The primary outcome was death from any
cause. Major secondary outcomes included death from cardiovascular causes and death
from any cause or hospitalization for cardiovascular causes. The median duration of
follow-up, including the current extended-follow-up study, was 9.8 years.
RESULTS
A primary outcome event occurred in 359 patients (58.9%) in the CABG group and in
398 patients (66.1%) in the medical-therapy group (hazard ratio with CABG vs. medical
therapy, 0.84; 95% confidence interval [CI], 0.73 to 0.97; P=0.02 by log-rank test). A
total of 247 patients (40.5%) in the CABG group and 297 patients (49.3%) in the
medical-therapy group died from cardiovascular causes (hazard ratio, 0.79; 95% CI,
0.66 to 0.93; P=0.006 by log-rank test). Death from any cause or hospitalization for
cardiovascular causes occurred in 467 patients (76.6%) in the CABG group and in 524
patients (87.0%) in the medical-therapy group (hazard ratio, 0.72; 95% CI, 0.64 to 0.82;
P<0.001 by log-rank test).
CONCLUSIONS
In a cohort of patients with ischemic cardiomyopathy, the rates of death from any
cause, death from cardiovascular causes, and death from any cause or hospitalization
for cardiovascular causes were significantly lower over 10 years among patients who
underwent CABG in addition to receiving medical therapy than among those who received
medical therapy alone. (Funded by the National Institutes of Health; STICH [and
STICHES] ClinicalTrials.gov number, NCT00023595.
Fucoidan Inhibition of Osteosarcoma Cells Is Species and Molecular Weight Dependent.
Fucoidan is a brown algae-derived polysaccharide having several biomedical applications. This study simultaneously compares the anti-cancer activities of crude fucoidans from Fucus vesiculosus and Sargassum filipendula, and effects of low (LMW, 10-50 kDa), medium (MMW, 50-100 kDa) and high (HMW, >100 kDa) molecular weight fractions of S. filipendula fucoidan against osteosarcoma cells. Glucose, fucose and acid levels were lower and sulphation was higher in F. vesiculosus crude fucoidan compared to S. filipendula crude fucoidan. MMW had the highest levels of sugars, acids and sulphation among molecular weight fractions. There was a dose-dependent drop in focal adhesion formation and proliferation of cells for all fucoidan-types, but F. vesiculosus fucoidan and HMW had the strongest effects. G1-phase arrest was induced by F. vesiculosus fucoidan, MMW and HMW, however F. vesiculosus fucoidan treatment also caused accumulation in the sub-G1-phase. Mitochondrial damage occurred for all fucoidan-types, however F. vesiculosus fucoidan led to mitochondrial fragmentation. Annexin V/PI, TUNEL and cytochrome c staining confirmed stress-induced apoptosis-like cell death for F. vesiculosus fucoidan and features of stress-induced necrosis-like cell death for S. filipendula fucoidans. There was also variation in penetrability of different fucoidans inside the cell. These differences in anti-cancer activity of fucoidans are applicable for osteosarcoma treatment
Stellar Chemical Signatures And Hierarchical Galaxy Formation
ABRIDGED: To compare the chemistries of stars in the Milky Way dSph galaxies
with stars in the Galaxy, we have compiled a large sample of Galactic stellar
abundances from the literature. As found in previous studies, the [alpha/Fe]
ratios of most stars in the dSph galaxies are generally lower than similar
metallicity Galactic stars in this extended sample. Our kinematically selected
stars confirm that this is true for all major stellar components of the Galaxy,
including the halo, thin disk, and thick disk. There is marginal overlap in the
low [alpha/Fe] ratios between dSph stars and Galactic halo stars on extreme
retrograde orbits, but this is not supported by other element ratios, like
[Ba/Y]. Thus, the full chemical signature of most of the dSph stars are
distinct from the main components of the Galaxy. This result rules out
continuous merging of low mass galaxies similar to these dSph satellites during
the formation of the Galaxy, which is discuss further. The new environments
offered by the dSph galaxies also allow us to examine fundamental assumptions
related to nucleosynthesis. The metal-poor stars ([Fe/H] < -1.8) in the dSph
galaxies have [alpha/Fe] ratio that are consistent with predictions from the
alpha-process (alpha-rich freeze out). This may also explain the very low Y
abundances, and could suggest a separate r-process site for this light (first
peak r-process) element. In stars with higher metallicities ([Fe/H] > -1.8),
contributions from the s-process are expected; [Ba/Y] is still much higher in
the dSph stars than similar metallicity Galactic stars though, consistent with
s-process contributions from only the low metallicity AGB stars in dSph
galaxies. Finally, the Na-Ni trend in Galactic halo stars is confirmed, but
discuss this in terms of nucleosynthesis, and not the accretion of dSphs.Comment: Accepted for Sept 2004 Astronomical Journal; 26 pages, 9 figures, 3
table
Swift XRT Observations of the Afterglow of XRF 050416A
Swift discovered XRF 050416A with the BAT and began observing it with its
narrow field instruments only 64.5 s after the burst onset. Its very soft
spectrum classifies this event as an X-ray flash. The afterglow X-ray emission
was monitored up to 74 days after the burst. The X-ray light curve initially
decays very fast, subsequently flattens and eventually steepens again, similar
to many X-ray afterglows. The first and second phases end about 172 and 1450 s
after the burst onset, respectively. We find evidence of spectral evolution
from a softer emission with photon index Gamma ~ 3.0 during the initial steep
decay, to a harder emission with Gamma ~ 2.0 during the following evolutionary
phases. The spectra show intrinsic absorption in the host galaxy. The
consistency of the initial photon index with the high energy BAT photon index
suggests that the initial phase of the X-ray light curve may be the low-energy
tail of the prompt emission. The lack of jet break signatures in the X-ray
afterglow light curve is not consistent with empirical relations between the
source rest-frame peak energy and the collimation-corrected energy of the
burst. The standard uniform jet model can give a possible description of the
XRF 050416A X-ray afterglow for an opening angle larger than a few tens of
degrees, although numerical simulations show that the late time decay is
slightly flatter than expected from on-axis viewing of a uniform jet. A
structured Gaussian-type jet model with uniform Lorentz factor distribution and
viewing angle outside the Gaussian core is another possibility, although a full
agreement with data is not achieved with the numerical models explored.Comment: Accepted for publication on ApJ; replaced with revised version: part
of the discussion moved in an appendix; 11 pages, 6 figures; abstract
shortened for posting on astro-p
Could very low-metallicity stars with rotation-dominated orbits have been shepherded by the bar?
The most metal-poor stars (e.g. [Fe/H] ) are the ancient fossils
from the early assembly epoch of our Galaxy, very likely before the formation
of the thick disc. Recent studies have shown that a non-negligible fraction of
them have prograde planar orbits, which makes their origin a puzzle. It has
been suggested that a later-formed rotating bar could have driven these old
stars from the inner Galaxy outward, and transformed their orbits to be more
rotation-dominated. However, it is not clear if this mechanism can explain
these stars as observed in the solar neighborhood. In this paper, we explore
the possibility of this scenario by tracing these stars backwards in an
axisymmetric Milky Way potential with a bar perturber. We integrate their
orbits backward for 6 Gyr under two bar models: one with a constant pattern
speed and another one with a decelerating speed. Our experiments show that,
under the constantly-rotating bar model, the stars of interest are little
affected by the bar and cannot have been shepherded from a spheroidal inner
Milky Way to their current orbits. In the extreme case of a rapidly
decelerating bar, some of the very metal-poor stars on planar and prograde
orbits can be brought from the inner Milky Way, but of them were
nevertheless already rotation-dominated ( 1000 km s
kpc) 6 Gyr ago. The chance of these stars having started with spheroid-like
orbits with small rotation ( 600 km s kpc) is very
low ( 3). We therefore conclude that, within the solar neighborhood, the
bar is unlikely to have shepherded a significant fraction of inner Galaxy
spheroid stars to produce the overdensity of stars on prograde, planar orbits
that is observed today.Comment: submitted to A&A, comments are welcom
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