366 research outputs found
Thrombotic microangiopathy as first manifestation of acute human immunodeficiency virus infection: a case report and review of the literature
Spectroscopic Confirmation of a Population of Isolated, Intermediate-Mass YSOs
Wide-field searches for young stellar objects (YSOs) can place useful
constraints on the prevalence of clustered versus distributed star formation.
The Spitzer/IRAC Candidate YSO (SPICY) catalog is one of the largest
compilations of such objects (~120,000 candidates in the Galactic midplane).
Many SPICY candidates are spatially clustered, but, perhaps surprisingly,
approximately half the candidates appear spatially distributed. To better
characterize this unexpected population and confirm its nature, we obtained
Palomar/DBSP spectroscopy for 26 of the optically-bright (G<15 mag) "isolated"
YSO candidates. We confirm the YSO classifications of all 26 sources based on
their positions on the Hertzsprung-Russell diagram, H and Ca II line-emission
from over half the sample, and robust detection of infrared excesses. This
implies a contamination rate of <10% for SPICY stars that meet our optical
selection criteria. Spectral types range from B4 to K3, with A-type stars most
common. Spectral energy distributions, diffuse interstellar bands, and Galactic
extinction maps indicate moderate to high extinction. Stellar masses range from
~1 to 7 , and the estimated accretion rates, ranging from
to yr, are typical for YSOs
in this mass range. The 3D spatial distribution of these stars, based on Gaia
astrometry, reveals that the "isolated" YSOs are not evenly distributed in the
Solar neighborhood but are concentrated in kpc-scale dusty Galactic structures
that also contain the majority of the SPICY YSO clusters. Thus, the processes
that produce large Galactic star-forming structures may yield nearly as many
distributed as clustered YSOs.Comment: Accepted for publication in AJ. 22 pages, 9 figures, and 4 tables.
Figure sets are available from
https://sites.astro.caltech.edu/~mkuhn/SPICY/PaperIII
Changes in SARS-CoV-2 viral load and mortality during the initial wave of the pandemic in New York City
Funding: This work was partially supported by the National Center for Advancing Translational Sciences of the National Institutes of Health (UL1 TR0023484 to Julianne Imperato-McGinley) and the National Institute of Allergy and Infectious Diseases (UM1 AI069470 to M.E.S).Public health interventions such as social distancing and mask wearing decrease the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, but it is unclear whether they decrease the viral load of infected patients and whether changes in viral load impact mortality from coronavirus disease 2019 (COVID-19). We evaluated 6923 patients with COVID-19 at six New York City hospitals from March 15-May 14, 2020, corresponding with the implementation of public health interventions in March. We assessed changes in cycle threshold (CT) values from reverse transcription-polymerase chain reaction tests and in-hospital mortality and modeled the impact of viral load on mortality. Mean CT values increased between March and May, with the proportion of patients with high viral load decreasing from 47.7% to 7.8%. In-hospital mortality increased from 14.9% in March to 28.4% in early April, and then decreased to 8.7% by May. Patients with high viral loads had increased mortality compared to those with low viral loads (adjusted odds ratio 2.34). If viral load had not declined, an estimated 69 additional deaths would have occurred (5.8% higher mortality). SARS-CoV-2 viral load steadily declined among hospitalized patients in the setting of public health interventions, and this correlated with decreases in mortality.Peer reviewe
Search for gravitational wave bursts in LIGO's third science run
We report on a search for gravitational wave bursts in data from the three
LIGO interferometric detectors during their third science run. The search
targets subsecond bursts in the frequency range 100-1100 Hz for which no
waveform model is assumed, and has a sensitivity in terms of the
root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No
gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published
in Classical and Quantum Gravit
Upper limits on the strength of periodic gravitational waves from PSR J1939+2134
The first science run of the LIGO and GEO gravitational wave detectors
presented the opportunity to test methods of searching for gravitational waves
from known pulsars. Here we present new direct upper limits on the strength of
waves from the pulsar PSR J1939+2134 using two independent analysis methods,
one in the frequency domain using frequentist statistics and one in the time
domain using Bayesian inference. Both methods show that the strain amplitude at
Earth from this pulsar is less than a few times .Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo
Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July
200
Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers
We study frequency dependent (FD) input-output schemes for signal-recycling
interferometers, the baseline design of Advanced LIGO and the current
configuration of GEO 600. Complementary to a recent proposal by Harms et al. to
use FD input squeezing and ordinary homodyne detection, we explore a scheme
which uses ordinary squeezed vacuum, but FD readout. Both schemes, which are
sub-optimal among all possible input-output schemes, provide a global noise
suppression by the power squeeze factor, while being realizable by using
detuned Fabry-Perot cavities as input/output filters. At high frequencies, the
two schemes are shown to be equivalent, while at low frequencies our scheme
gives better performance than that of Harms et al., and is nearly fully
optimal. We then study the sensitivity improvement achievable by these schemes
in Advanced LIGO era (with 30-m filter cavities and current estimates of
filter-mirror losses and thermal noise), for neutron star binary inspirals, and
for narrowband GW sources such as low-mass X-ray binaries and known radio
pulsars. Optical losses are shown to be a major obstacle for the actual
implementation of these techniques in Advanced LIGO. On time scales of
third-generation interferometers, like EURO/LIGO-III (~2012), with
kilometer-scale filter cavities, a signal-recycling interferometer with the FD
readout scheme explored in this paper can have performances comparable to
existing proposals. [abridged]Comment: Figs. 9 and 12 corrected; Appendix added for narrowband data analysi
How Typical Are The Local Group Dwarf Galaxies?
We compare the cumulative star formation histories (SFHs) of Local Group (LG)
dwarf galaxies with those in the volume-limited ACS Nearby Galaxy Survey
Treasury (ANGST) sample (D < 4 Mpc), in order to understand how typical the LG
dwarf galaxies are relative to those in the nearby universe. The SFHs were
derived in a uniform manner from high quality optical color-magnitude diagrams
constructed from Hubble Space Telescope imaging. We find that the {\it mean}
cumulative SFHs of the LG dwarfs are comparable to the mean cumulative SFHs of
the ANGST sample for the three different morphological types (dwarf
spheroidals/ellipticals: dSph/dE; dwarf irregulars: dI; transition dwarfs:
dTrans). We also discuss effects such as population gradients and systematic
uncertainties in the stellar models that may influence the derived SFHs. Both
the ANGST and Local Group dwarf galaxies show a consistent and strong
morphology-density relationship, emphasizing the importance of environment in
the evolution of dwarf galaxies. Specifically, we confirm that dIs are found at
lower densities and higher luminosities than dSphs, within this large sample.
We also find that dTrans are located in similar environments to those occupied
by dwarf irregular galaxies, but have systematically lower luminosities that
are more comparable to those of dwarf spheroidals. The similarity of the SFHs
and morphology-density relationships of the LG and ANGST dwarf galaxies
suggests that the LG dwarfs are a good representation of dwarf galaxies in the
local universe.Comment: 10 pages, 4 figures. Accepted to Ap
Plasma fibrin D-dimer levels correlate with tumour volume, progression rate and survival in patients with metastatic breast cancer
Plasma levels of D-dimer are elevated in cancer patients. Activation of the extrinsic coagulation system and the fibrinolytic cascade within a tumour is thought to be related with growth, invasion and metastasis. We have investigated the relationship between these markers of fibrin metabolism, standard clinicopathological variables and serum levels of angiogenic cytokines in three cohorts: group A (n=30) consisted of 30 healthy female volunteers, group B (n=23) of consecutive patients with operable breast cancer and group C (n=84) of patients with untreated or progressive metastatic breast cancer. Plasma D-dimers, fibrinogen, IL-6, vascular endothelial growth factor and calculated vascular endothelial growth factor load in platelets are clearly increased in patients with breast cancer. D-dimers were increased in nearly 89% of patients with progressive metastatic disease. The level of D-dimers was positively correlated with tumour load (P<0.0001), number of metastatic sites (P=0.002), progression kinetics (P<0.0001) and the cytokines related to angiogenesis: serum vascular endothelial growth factor (P=0.0016, Spearman correlation=0.285), calculated vascular endothelial growth factor load in platelets (P<0.0001, Spearman correlation=0.37) and serum interleukin-6 (P<0.0001, Spearman correlation=0.59). Similarly increased D-dimer levels were positively correlated with increased fibrinogen levels (P<0.0001, Spearman correlation=0.38). The association between markers of fibrin degradation in patients with progressive breast cancer suggests that the D-dimer level is a clinically important marker for progression and points towards a relation between haemostasis and tumour progression. A role of interleukin-6, by influencing both angiogenesis and haemostasis, is suggested by these observations
Alexithymia may explain the relationship between autistic traits and eating disorder psychopathology
Background: Autistic people are disproportionately vulnerable to anorexia nervosa and other eating disorders (ED), and within the general population, autistic traits correlate with ED psychopathology. A putative mechanism which may underpin this heightened risk is alexithymia, a difficulty identifying and describing emotional states which is
observed in both autism and ED. In two experiments with independent non-clinical samples, we explored whether alexithymia might mediate the heightened risk of eating psychopathology in individuals high in autistic traits.
Methods: Our first experiment used the PROCESS macro for SPSS to examine relationships between alexithymia (measured by the Toronto Alexithymia Scale (TAS-20)), autistic traits (autism quotient (AQ)), and eating psychopathology (Eating Attitudes Test (EAT-26)) in 121 participants. Our second experiment (n = 300) replicated and furthered this analysis by examining moderating effects of sex and controlling for anxiety and depression as covariates. We also included an additional performance-based measure of alexithymia, the Levels of Emotional
Awareness Scale (LEAS).
Results: Study 1 suggested that TAS-20 scores mediated the relationship between heightened autistic traits and eating psychopathology. Replication and further scrutiny of this finding, in study 2, revealed that this mediation effect was partial and specific to the female participants in this sample. The mediation effect appeared to be carried
by the difficulty identifying feelings subscale of the TAS-20, even when depression and anxiety were controlled for. LEAS scores, however, were not significantly related to autistic traits or eating psychopathology.
Limitations: Cross-sectional data prevents any conclusions around the direction and causality of relationships between alexithymia, autistic traits, and eating psychopathology (alongside depression and anxiety), necessitating longitudinal research. Our non-clinical sample was predominantly Caucasian undergraduate students, so it remains
to be seen if these results would extrapolate to clinical and/or autistic samples. Divergence between the TAS-20 and LEAS raises crucial questions regarding the construct validity of these measures.
Conclusions: Our findings with respect to autistic traits suggest that alexithymia could partially explain the prevalence of ED in autistic people and may as such be an important consideration in the pathogenesis and
treatment of ED in autistic and non-autistic people alike. Further research with clinical samples is critical to explore these ideas. Differences between men and women, furthermore, emphasize the importance of looking for sexspecific as well as generic risk factors in autistic and non-autistic men and women
SEDIGISM: Structure, excitation, and dynamics of the inner Galactic interstellar medium
The origin and life-cycle of molecular clouds are still poorly constrained, despite their importance for understanding the evolution of the interstellar medium. Many large-scale surveys of the Galactic plane have been conducted recently, allowing for rapid progress in this field. Nevertheless, a sub-arcminute resolution global view of the large-scale distribution of molecular gas, from the diffuse medium to dense clouds and clumps, and of their relationshipto the spiral structure, is still missing. Aims. We have carried out a systematic, homogeneous, spectroscopic survey of the inner Galactic plane, in order to complement the many continuum Galactic surveys available with crucial distance and gas-kinematic information. Our aim is to combine this data set with recent infrared to sub-millimetre surveys at similar angular resolutions. © 2017 ESO
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