9,085 research outputs found
Standardized Consent Forms for Surgical Procedures: An Intervention to Improve the Resident-led Informed Consent Process
Objectives and Goals:
To provide high quality, consistent consent forms for common surgical procedures and improve resident workflow by creating and implementing standardized printed consents for common surgical procedures.
These consents will be used by residents consenting patients in the ED or inpatient setting.
Consents shall include standardized procedure descriptions, risks and benefits of the procedure, and alternative treatment option descriptions, risks and benefitshttps://jdc.jefferson.edu/patientsafetyposters/1057/thumbnail.jp
Rotational transition, domain formation, dislocations and defects in vortex systems with combined six- and 12-fold anisotropic interactions
We introduce a new model for a pairwise repulsive interaction potential of
vortices in a type-II superconductor, consisting of superimposed six- and
12-fold anisotropies. Using numerical simulations we study how the vortex
lattice configuration varies as the magnitudes of the two anisotropic
interaction terms change. A triangular lattice appears for all values, and
rotates through 30 degrees as the ratio of the six- and 12-fold anisotropy
amplitudes is varied. The transition causes the VL to split into domains that
have rotated clockwise or counter-clockwise, with domain boundaries that are
"decorated" by dislocations consisting of five- and seven-fold coordinated
vortices. We also find intra-domain dislocations and defects, and characterize
them in terms of their energy cost. We discuss how this model could be
generalized to other particle-based systems with anisotropic interactions, such
as colloids, and consider the limit of very large anisotropy where it is
possible to create cluster crystal states.Comment: 15 pages, 13 figures; minor revisions throughout tex
M\"ossbauer studies of powdered single crystals of FeTe0.5Se0.5
The M\"ossbauer measurements performed on powdered single crystals of
FeTe0.5Se0.5 (Tc ~ 14.7 K) reveal minor content of two impurity phases,
identified as Fe3O4 and Fe7Se8, among the major tetragonal phase. From the
shape of impurity subspectra it follows that Fe7Se8 behaves in
superparamagnetic manner, most likely because of randomly distributed Fe
vacancies in the lattice structure of Fe Te Se. The magnetite content in the
powdered absorber exposed to ambient air conditions remains unchanged during
period of 16 months. Ageing effects were observed for the samples stored under
argon atmosphere and small increase of the isomer shift of the doublet was
detected. Presented temperature dependence of the hyperfine parameters can be
explained as due to possible orthorhombic distortion or to temperature
behaviour of impurity phases Fe3O4 and Fe7Se8. Strong tendency to formation of
crystalline texture of powdered sample is observed.Comment: 13 pages, 8 figure
Exploring the Chemical Composition and Double Horizontal Branch of the Bulge Globular Cluster NGC 6569
Photometric and spectroscopic analyses have shown that the Galactic bulge
cluster Terzan 5 hosts several populations with different metallicities and
ages that manifest as a double red horizontal branch (HB). A recent
investigation of the massive bulge cluster NGC 6569 revealed a similar, though
less extended, HB luminosity split, but little is known about the cluster's
detailed chemical composition. Therefore, we have used high-resolution spectra
from the Magellan-M2FS and VLT-FLAMES spectrographs to investigate the chemical
compositions and radial velocity distributions of red giant branch and HB stars
in NGC 6569. We found the cluster to have a mean heliocentric radial velocity
of -48.8 km/s (sigma = 5.3 km/s; 148 stars) and a mean [Fe/H] =-0.87 dex (19
stars), but the cluster's 0.05 dex [Fe/H] dispersion precludes a significant
metallicity spread. NGC 6569 exhibits light- and heavy-element distributions
that are common among old bulge/inner Galaxy globular clusters, including clear
(anti)correlations between [O/Fe], [Na/Fe], and [Al/Fe]. The light-element data
suggest that NGC 6569 may be composed of at least two distinct populations, and
the cluster's low mean [La/Eu] = -0.11 dex indicates significant pollution with
r-process material. We confirm that both HBs contain cluster members, but
metallicity and light-element variations are largely ruled out as sources for
the luminosity difference. However, He mass fraction differences as small as
delta Y ~ 0.02 cannot be ruled out and may be sufficient to reproduce the
double HB.Comment: 72 pages, 14 figures, 8 tables; published in The Astronomical
Journal; electronic versions of all tables are available in the published
versio
A Chemical Composition Survey of the Iron-Complex Globular Cluster NGC 6273 (M 19)
Recent observations have shown that a growing number of the most massive
Galactic globular clusters contain multiple populations of stars with different
[Fe/H] and neutron-capture element abundances. NGC 6273 has only recently been
recognized as a member of this "iron-complex" cluster class, and we provide
here a chemical and kinematic analysis of > 300 red giant branch (RGB) and
asymptotic giant branch (AGB) member stars using high resolution spectra
obtained with the Magellan-M2FS and VLT-FLAMES instruments. Multiple lines of
evidence indicate that NGC 6273 possesses an intrinsic metallicity spread that
ranges from about [Fe/H] = -2 to -1 dex, and may include at least three
populations with different [Fe/H] values. The three populations identified here
contain separate first (Na/Al-poor) and second (Na/Al-rich) generation stars,
but a Mg-Al anti-correlation may only be present in stars with [Fe/H] > -1.65.
The strong correlation between [La/Eu] and [Fe/H] suggests that the s-process
must have dominated the heavy element enrichment at higher metallicities. A
small group of stars with low [alpha/Fe] is identified and may have been
accreted from a former surrounding field star population. The cluster's large
abundance variations are coupled with a complex, extended, and multimodal blue
horizontal branch (HB). The HB morphology and chemical abundances suggest that
NGC 6273 may have an origin that is similar to omega Cen and M 54.Comment: Accepted for Publication in The Astrophysical Journal; 50 pages; 18
figures; 8 tables; higher resolution figures are available upon request or in
the published journal articl
Photometry and spectroscopy of faint candidate spectrophotometric standard DA white dwarfs
We present precise photometry and spectroscopy for 23 candidate
spectrophotometric standard white dwarfs. The selected stars are distributed in
the Northern hemisphere and around the celestial equators and are all fainter
than r ~ 16.5 mag. This network of stars, when established as standards,
together with the three Hubble Space Telescope primary CALSPEC white dwarfs,
will provide a set of spectrophotometric standards to directly calibrate data
products to better than 1%. These new faint standard white dwarfs will have
enough signal-to-noise ratio in future deep photometric surveys and facilities
to be measured accurately while still avoiding saturation in such surveys. They
will also fall within the dynamic range of large telescopes and their
instruments for the foreseeable future. This paper discusses the provenance of
the observational data for our candidate standard stars. The comparison with
models, reconciliation with reddening, and the consequent derivation of the
full spectral energy density distributions for each of them is reserved for a
subsequent paper.Comment: 31 pages, 17 figures, 10 tables, ApJ in press (accepted on December
23rd, 2018
Stellar luminosity functions of rich star clusters in the Large Magellanic Cloud
We show the results of deep V and I HST photometry of 6 rich star clusters in
the Large Magellanic Cloud with different ages and metallicities. The number of
stars with measured magnitudes in each cluster varies from about 3000 to 10000.
We build stellar density and surface brightness profiles for the clusters and
extract half-light radii and other structural parameters for each. We also
obtain luminosity functions, Phi (Mv), down to Mv ~ 6 (m/msun > 0.6), and
investigate their dependence with distance from the cluster centre well beyond
their half-light radius. In all clusters we find a systematic increase in the
luminosity function slope with radial distance from the centre. Among the
clusters displaying significant mass segregation are the two youngest in the
sample: NGC 1805 and NGC 1818. For these two clusters we obtain present-day
mass functions. The NGC 1818 mass function is in excellent agreement with that
derived by other authors, also using HST data. They young cluster mass function
slopes differ, that of NCG 1805 being systematically steeper than NGC 1818.
Since these are very young stellar systems (age < 40 Myrs), these variations
may reflect the initial conditions rather than evolution due to internal
dynamics.Comment: 10 pages, 24 figure
- …
