233 research outputs found
Wide-field dynamic astronomy in the near-infrared with Palomar Gattini-IR and DREAMS
There have been a dramatic increase in the number of optical and radio transient surveys due to astronomical transients such as gravitational waves and gamma ray bursts, however, there have been a limited number of wide-field infrared surveys due to narrow field-of-view and high cost of infrared cameras, we present two new wide-field near-infrared fully automated surveyors; Palomar Gattini-IR and the Dynamic REd All-sky Monitoring Survey (DREAMS). Palomar Gattini-IR, a 25 square degree J-band imager that begun science operations at Palomar Observatory, USA in October 2018; we report on survey strategy as well as telescope and observatory operations and will also providing initial science results. DREAMS is a 3.75 square degree wide-field imager that is planned for Siding Spring Observatory, Australia; we report on the current optical and mechanical design and plans to achieve on-sky results in 2020. DREAMS is on-track to be one of the first astronomical telescopes to use an Indium Galium Arsenide (InGaAs) detector and we report initial on-sky testing results for the selected detector package. DREAMS is also well placed to take advantage and provide near-infrared follow-up of the LSST
: Probing the Milky Way and Magellanic Clouds potentials with the 6-D map of the Orphan-Chenab stream
We present a 6-D map of the Orphan-Chenab (OC) stream by combining the data
from 5 years of Southern Stellar Stream Spectroscopic Survey observations
with Gaia EDR3 data. We reconstruct the proper motion, radial velocity,
distance and on-sky track of stream stars with spline models and extract the
stellar density along the stream. The stream has a total luminosity of
and an average metallicity of , similar to classical MW
satellites like Draco. The stream shows drastic changes in its physical width
varying from 200 pc to 1 kpc, a constant line of sight velocity dispersion of 5
km/s, but an increase in the velocity dispersion along the stream near
pericenter to 10 km/s. Despite the large apparent variation in the
stellar number density along the stream, the flow rate of stars along the
stream is remarkably constant. We model the 6-D stream track by a
Lagrange-point stripping method with a flexible MW potential in the presence of
a moving extended LMC potential. This allows us to constrain the mass profile
of the MW within the distance range 15.6 < r < 55.5 kpc, with the best measured
enclosed mass of within 32.4 kpc. With
the OC stream's closest approach distance to the LMC of kpc, our
stream measurements are highly sensitive to the LMC mass profile with the most
precise measurement of the LMC's enclosed mass being at 32.8 kpc with
. We confidently detect that the LMC
DM halo extends to at least 53 kpc. The fitting of the OC stream allows us to
constrain the past LMC trajectory and the degree of dynamical friction it
experienced. We demonstrate that the stars on the OC stream show large energy
and angular momentum spreads caused by the LMC perturbation and revealing the
limitations of orbital invariants for substructure identification in the MW
halo.Comment: submitted to MNRAS; comments welcome; data released with the paper is
available on Zenodo https://zenodo.org/record/722265
Reduced functional measure of cardiovascular reserve predicts admission to critical care unit following kidney transplantation
Background: There is currently no effective preoperative assessment for patients undergoing kidney transplantation that is
able to identify those at high perioperative risk requiring admission to critical care unit (CCU). We sought to determine if
functional measures of cardiovascular reserve, in particular the anaerobic threshold (VO2AT) could identify these patients.
Methods: Adult patients were assessed within 4 weeks prior to kidney transplantation in a University hospital with a 37-bed
CCU, between April 2010 and June 2012. Cardiopulmonary exercise testing (CPET), echocardiography and arterial
applanation tonometry were performed.
Results: There were 70 participants (age 41.7614.5 years, 60% male, 91.4% living donor kidney recipients, 23.4% were
desensitized). 14 patients (20%) required escalation of care from the ward to CCU following transplantation. Reduced
anaerobic threshold (VO2AT) was the most significant predictor, independently (OR = 0.43; 95% CI 0.27–0.68; p,0.001) and
in the multivariate logistic regression analysis (adjusted OR = 0.26; 95% CI 0.12–0.59; p = 0.001). The area under the receiveroperating-
characteristic curve was 0.93, based on a risk prediction model that incorporated VO2AT, body mass index and
desensitization status. Neither echocardiographic nor measures of aortic compliance were significantly associated with CCU
admission.
Conclusions: To our knowledge, this is the first prospective observational study to demonstrate the usefulness of CPET as a
preoperative risk stratification tool for patients undergoing kidney transplantation. The study suggests that VO2AT has the
potential to predict perioperative morbidity in kidney transplant recipients
Signature of a massive rotating metal-poor star imprinted in the Phoenix stellar stream*
The Phoenix stellar stream has a low intrinsic dispersion in velocity and
metallicity that implies the progenitor was probably a low mass globular
cluster. In this work we use Magellan/MIKE high-dispersion spectroscopy of
eight Phoenix stream red giants to confirm this scenario. In particular, we
find negligible intrinsic scatter in metallicity () and a large peak-to-peak range in [Na/Fe] and [Al/Fe]
abundance ratios, consistent with the light element abundance patterns seen in
the most metal-poor globular clusters. However, unlike any other globular
cluster, we also find an intrinsic spread in [Sr II/Fe] spanning 1 dex,
while [Ba II/Fe] shows nearly no intrinsic spread (). This abundance signature is best interpreted as
slow neutron capture element production from a massive fast-rotating metal-poor
star (, ,
). The low inferred cluster mass suggests the system
would have been unable to retain supernovae ejecta, implying that any massive
fast-rotating metal-poor star that enriched the interstellar medium must have
formed and evolved before the globular cluster formed. Neutron capture element
production from asymptotic giant branch stars or magneto-rotational
instabilities in core-collapse supernovae provide poor fits to the
observations. We also report one Phoenix stream star to be a lithium-rich giant
(). At it is among the
most metal-poor lithium-rich giants known.Comment: Accepted to ApJ 2021-07-0
Broken into Pieces::ATLAS and Aliqa Uma as One Single Stream
We present the first spectroscopic measurements of the ATLAS and Aliqa Uma
streams from the Southern Stellar Stream Spectroscopic Survey (), in
combination with the photometric data from the Dark Energy Survey and
astrometric data from . From the coherence of spectroscopic members in
radial velocity and proper motion, we find out that these two systems are
extremely likely to be one stream with discontinuity in morphology and density
on the sky (the "kink" feature). We refer to this entire stream as the
ATLAS-Aliqa Uma stream, or the AAU stream. We perform a comprehensive
exploration of the effect of baryonic substructures and find that only an
encounter with the Sagittarius dwarf Gyr ago can create a feature
similar to the observed "kink". In addition, we also identify two gaps in the
ATLAS component associated with the broadening in the stream width (the
"broadening" feature). These gaps have likely been created by small mass
perturbers, such as dark matter halos, as the AAU stream is the most distant
cold stream known with severe variations in both the stream surface density and
the stream track on the sky. With the stream track, stream distance and
kinematic information, we determine the orbit of the AAU stream and find that
it has been affected by the Large Magellanic Cloud, resulting in a misalignment
between the proper motion and stream track. Together with the Orphan-Chenab
Stream, AAU is the second stream pair that has been found to be a single stream
separated into two segments by external perturbation.Comment: 33 pages, 22 figures (including 1 movie), 3 tables. Accepted for
publication in Ap
Cardiovascular magnetic resonance imaging of myocardial oedema following acute myocardial infarction: Is whole heart coverage necessary?
© 2016 Hamshere et al. Background: AAR measurement is useful when assessing the efficacy of reperfusion therapy and novel cardioprotective agents after myocardial infarction. Multi-slice (Typically 10-12) T2-STIR has been used widely for its measurement, typically with a short axis stack (SAX) covering the entire left ventricle, which can result in long acquisition times and multiple breath holds. This study sought to compare 3-slice T2-short-tau inversion recovery (T2- STIR) technique against conventional multi-slice T2-STIR technique for the assessment of area at risk (AAR). Methods: CMR imaging was performed on 167 patients after successful primary percutaneous coronary intervention. 82 patients underwent a novel 3-slice SAX protocol and 85 patients underwent standard 10-slice SAX protocol. AAR was obtained by manual endocardial and epicardial contour mapping followed by a semi- automated selection of normal myocardium; the volume was expressed as mass (%) by two independent observers. Results: 85 patients underwent both 10-slice and 3-slice imaging assessment showing a significant and strong correlation (intraclass correlation coefficient = 0.92;p < 0.0001) and a low Bland-Altman limit (mean difference -0.03 ± 3.21 %, 95 % limit of agreement,- 6.3 to 6.3) between the 2 analysis techniques. A further 82 patients underwent 3-slice imaging alone, both the 3-slice and the 10-slice techniques showed statistically significant correlations with angiographic risk scores (3-slice to BARI r = 0.36, 3-slice to APPROACH r = 0.42, 10-slice to BARI r = 0.27, 10-slice to APPROACH r = 0.46). There was low inter-observer variability demonstrated in the 3-slice technique, which was comparable to the 10-slice method (z = 1.035, p = 0.15). Acquisition and analysis times were quicker in the 3-slice compared to the 10-slice method (3-slice median time: 100 seconds (IQR: 65-171 s) vs (10-slice time: 355 seconds (IQR: 275-603 s); p < 0.0001. Conclusions: AAR measured using 3-slice T2-STIR technique correlates well with standard 10-slice techniques, with no significant bias demonstrated in assessing the AAR. The 3-slice technique requires less time to perform and analyse and is therefore advantageous for both patients and clinicians
Sherman, Shakers, and Shenanigans
The first 122 pages of this book relate to Bulloch County and form Book 10: Readings in Bulloch County History. The remainder comprise the Southern Folkways Journal Review No. 3, and relate to Southeast Georgia and to the Southeastern region of the United States. The first collection begins with a poem by Dr. John Ransom Lewis, followed by three articles on Dan Bland and the biographies of prominent African American citizens. Also included are two articles on the Hardy Moore family, student papers on vanishing Bulloch County communities, information on Joseph Jackson, articles on three local churches, and the Muster Roll of Toombs Guards. The second section of this book begins with an article on Western Shakers by Dr. Dale Covington, followed by “Hostau Reminisces,” and several articles on the Cherokee and the Lumbee Indians.https://digitalcommons.georgiasouthern.edu/bchs-pubs/1033/thumbnail.jp
The Bandim TBscore – reliability, further development, and evaluation of potential uses
Background: The tuberculosis (TB) case detection rate has stagnated at 60% due to disorganized case finding and insensitivity of sputum smear microscopy. Of the identified TB cases, 4% die while being treated, monitored with tools that insufficiently predict failure/mortality. Objective: To explore the TBscore, a recently proposed clinical severity measure for pulmonary TB (PTB) patients, and to refine, validate, and investigate its place in case finding. Design: The TBscore's inter-observer agreement was assessed and compared to the Karnofsky Performance Score (KPS) (paper I). The TBscore's variables underlying constructs were assessed, sorting out unrelated items, proposing a more easily assessable TBscoreII, which was validated internally and externally (paper II). Finally, TBscore and TBscoreII's place in PTB-screening was examined in paper III. Results: The inter-observer variability when grading PTB patients into severity classes was moderate for both TBscore (κ
W=0.52, 95% CI 0.46–0.56) and KPS (κ
W=0.49, 95% CI 0.33–0.65). KPS was influenced by HIV status, whereas TBscore was unaffected by it. In paper II, proposed TBscoreII was validated internally, in Guinea-Bissau, and externally, in Ethiopia. In both settings, a failure to bring down the score by ≥25% from baseline to 2 months of treatment predicted subsequent failure (p=0.007). Finally, in paper III, TBscore and TBscoreII were assessed in health-care-seeking adults and found to be higher in PTB-diagnosed patients, 4.9 (95% CI 4.6–5.2) and 3.9 (95% CI 3.8–4.0), respectively, versus patients not diagnosed with PTB, 3.0 (95% CI 2.7–3.2) and 2.4 (95% CI 2.3–2.5), respectively. Had we referred only patients with cough >2 weeks to sputum smear, we would have missed 32.1% of the smear confirmed cases in our cohort. A TBscoreII>=2 missed 8.6%. Conclusions: TBscore and TBscoreII are useful monitoring tools for PTB patients on treatment, as they could fill the void which currently exists in risk grading of patients. They may also have a role in PTB screening; however, this requires our findings to be repeated elsewhere
Wide-field dynamic astronomy in the near-infrared with Palomar Gattini-IR and DREAMS
There have been a dramatic increase in the number of optical and radio transient surveys due to astronomical transients such as gravitational waves and gamma ray bursts, however, there have been a limited number of wide-field infrared surveys due to narrow field-of-view and high cost of infrared cameras, we present two new wide-field near-infrared fully automated surveyors; Palomar Gattini-IR and the Dynamic REd All-sky Monitoring Survey (DREAMS). Palomar Gattini-IR, a 25 square degree J-band imager that begun science operations at Palomar Observatory, USA in October 2018; we report on survey strategy as well as telescope and observatory operations and will also providing initial science results. DREAMS is a 3.75 square degree wide-field imager that is planned for Siding Spring Observatory, Australia; we report on the current optical and mechanical design and plans to achieve on-sky results in 2020. DREAMS is on-track to be one of the first astronomical telescopes to use an Indium Galium Arsenide (InGaAs) detector and we report initial on-sky testing results for the selected detector package. DREAMS is also well placed to take advantage and provide near-infrared follow-up of the LSST
Monocyte Chemotactic Protein-1 (MCP-1) and Growth Factors Called into Question as Markers of Prolonged Psychosocial Stress
BACKGROUND:Psychosocial stress is becoming a major contributor to increased mental ill-health and sick leave in many countries. Valid markers of chronic stress would be valuable for diagnostic and prognostic purposes. A recent study suggested monocyte chemotactic protein-1 (MCP-1), epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) as markers of chronic stress. We aimed to confirm these potential biomarkers of prolonged psychosocial stress in female patients. METHODOLOGY/PRINCIPAL FINDINGS:Circulating levels of MCP-1, EGF and VEGF, along with several other cytokines, were measured in plasma from 42 female patients suffering from exhaustion due to prolonged psychosocial stress and 42 control subjects, using a protein biochip immunoassay. There were no significant differences between patients and controls in any of the cytokines or growth factors analyzed. Furthermore, when using a different protein bioassay and reanalyzing MCP-1 and VEGF in the same samples, markedly different levels were obtained. To further explore if inflammation is present in patients with exhaustion, the classical inflammatory marker C-reactive protein (CRP) was measured in another group of patients (n=89) and controls (n=88) showing a small but significant increase of CRP levels in the patients. CONCLUSIONS/SIGNIFICANCE:MCP-1, EGF and VEGF may not be suitable markers of prolonged psychosocial stress as previously suggested. Furthermore, significant differences were obtained when using two different protein assays measuring the same samples, indicating that comparing studies where different analytic techniques have been used might be difficult. Increased levels of CRP indicate that low-grade inflammation might be present in patients with exhaustion due to prolonged stress exposure but this inflammation does not seem to be reflected by increase in circulating MCP-1 or other cytokines measured
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