We present ~ 126 new spectroscopically identified members of the GD-1 tidal
stream obtained with the 5000-fiber Dark Energy Spectroscopic Instrument
(DESI). We confirm the existence of a ``cocoon'' ...which is broad
(FWHM~2.932deg~460pc) and kinematically hot (velocity dispersion,
sigma~5-8km/s) component that surrounds a narrower (FWHM~0.353deg~55pc) and
colder (sigma~ 2.2-2.6km/s) thin stream component (based on a median per star
velocity precision of 2.7km/s). The cocoon extends over at least a ~ 20deg
segment of the stream observed by DESI. The thin and cocoon components have
similar mean values of Fe/H: -2.54+/- 0.04dex and -2.45+/-0.06dex suggestive
of a common origin. The data are consistent with the following scenarios for
the origin of the cocoon. The progenitor of the GD-1 stream was an accreted
globular cluster (GC) and: (a) the cocoon was produced by pre-accretion tidal
stripping of the GC while it was still inside its parent dwarf galaxy; (b) the
cocoon is debris from the parent dwarf galaxy; (c) an initially thin GC tidal
stream was heated by impacts from dark subhalos in the Milky Way; (d) an
initially thin GC stream was heated by a massive Sagittarius dwarf galaxy; or a
combination of some these. In the first two cases the velocity dispersion and
mean metallicity are consistent with the parent dwarf galaxy having a halo mass
of ~0^9\msun. Future DESI spectroscopy and detailed modeling may enable us to
distinguish between these possible origins.
The discovery of very distant stars in the halo of the Milky Way provides valuable tracers on the Milky Way mass and its formation. Beyond 100 kpc from the Galactic center, most of the stars are ...likely to be in faint dwarf galaxies or tidal debris from recently accreted dwarfs, making the outer reaches of the Galaxy important for understanding the Milky Way's accretion history. However, distant stars in the halo are scarce. In that context, RR Lyrae are ideal probes of the distant halo as they are intrinsically bright and thus can be seen at large distances, follow well-known period-luminosity relations that enable precise distance measurements, and are easily identifiable in time-series data. Therefore, a detailed study of RR Lyrae will help us understand the accreted outskirts of the Milky Way. In this contribution, we present the current state of our systematic search for distant RR Lyrae stars in the halo using the DECam imager at the 4m telescope on Cerro Tololo (Chile). The total surveyed area consists of more than 110 DECam fields (~ 350 sq. deg) and includes two recent independent campaigns carried out in 2017 and 2018 with which we have detected > 650 candidate RR Lyrae stars. Here we describe the methodology followed to analyze the two latest campaigns. Our catalog contains a considerable number of candidate RR Lyrae beyond 100 kpc, and reaches out up to ~ 250 kpc. The number of distant RR Lyrae found is consistent with recent studies of the outer halo. These stars provide a set of important probes of the mass of the Milky Way, the nature of the halo, and the accretion history of the Galactic outskirts.
We aim at clarifying the nature of the emission of two spatially related unidentified X-ray sources detected with XMM-Newton telescope at intermediate-low Galactic latitude. Observations reveal a ...point-like source aligned with elongated diffuse emission. The X-ray spectra are best-fitted by absorbed power laws with photon indices ~1.7 for the point-like and ~2.0 for the extended one. Both sources show nonthermal radio-continuum counterparts that might indicate a physical association. From the available data, we did not detect variability on the point-like source in several timescales. Two possible scenarios are analyzed: first, based on HI line absorption, assuming a Galactic origin, we infer a distance upper bound of <2 kpc, which poses a constraint on the height over the Galactic plane of <200 pc and on the linear size of the system of <2.3 pc. In this case, the X-ray luminosities are >10^32 erg/s and >7.5 x 10^32 erg/s, for the point-like and extended sources, respectively; second, an extra-Galactic nature is discussed, where the point-like source might be the core of a radio galaxy and the extended source its lobe. In this case, we compare derived fluxes, spectral indices, and spatial correlation with those typical from the radio galaxy population, showing the feasibility of this alternative astrophysical scenario. From the available observational evidence, we suggest that the most promising scenario to explain the nature of these sources is a system consisting of a one-sided radio galaxy, where the point-like source is an active galactic nucleus and the extended source corresponds to the emission from its lobe. Other possibilities include a PSR/PWN origin, where the radio/X-ray emission originates from the synchrotron cooling of relativistic particles in the PSR magnetic field or a casual alignment between two unrelated sources, such as an AGN core and a Galactic X-ray blob.
During the analysis of RR Lyrae stars discovered in the High cadence Transient Survey (HiTS) taken with the Dark Energy Camera at the 4-m telescope at Cerro Tololo Inter-American Observatory, we ...found a group of three very distant, fundamental mode pulsator RR Lyrae (type ab). The location of these stars agrees with them belonging to the Leo V ultra-faint satellite galaxy, for which no variable stars have been reported to date. The heliocentric distance derived for Leo V based on these stars is 173 +/- 5 kpc. The pulsational properties (amplitudes and periods) of these stars locate them within the locus of the Oosterhoff II group, similar to most other ultra-faint galaxies with known RR Lyrae stars. This serendipitous discovery shows that distant RR Lyrae stars may be used to search for unknown faint stellar systems in the outskirts of the Milky Way.
We study the production of VHE emission in blazars as a superposition of a steady component from a baryonic jet and a time- dependent contribution from an inner e-e+ beam launched by the black hole. ...Both primary relativistic electrons and protons are injected in the jet, and the particle distributions along it are found by solving a one-dimensional transport equation that accounts for convection and cooling. The short-timescale variability of the emission is explained by local pair injections in turbulent regions of the inner beam. For illustration, we apply the model to the case of PKS 2155-304, reproducing a quiescent state of emission with inverse Compton and synchrotron radiation from primary electrons, as well as proton-proton interactions in the jet. The latter also yield an accompanying neutrino flux that could be observed with a new generation km-scale detector in the northern hemisphere such as KM3NeT.
In this paper we describe QUBIC, an experiment that will observe the polarized microwave sky with a novel approach, which combines the sensitivity of state-of-the art bolometric detectors with the ...systematic effects control typical of interferometers. QUBIC unique features are the so-called "self-calibration", a technique that allows us to clean the measured data from instrumental effects, and its spectral imaging power, i.e. the ability to separate the signal in various sub-bands within each frequency band. QUBIC will observe the sky in two main frequency bands: 150 GHz and 220 GHz. A technological demonstrator is currently under testing and will be deployed in Argentina during 2019, while the final instrument is expected to be installed during 2020.
The effect of high-flow oxygen therapy vs conventional oxygen therapy has not been established in the setting of severe COVID-19.
To determine the effect of high-flow oxygen therapy through a nasal ...cannula compared with conventional oxygen therapy on need for endotracheal intubation and clinical recovery in severe COVID-19.
Randomized, open-label clinical trial conducted in emergency and intensive care units in 3 hospitals in Colombia. A total of 220 adults with respiratory distress and a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen of less than 200 due to COVID-19 were randomized from August 2020 to January 2021, with last follow-up on February 10, 2021.
Patients were randomly assigned to receive high-flow oxygen through a nasal cannula (n = 109) or conventional oxygen therapy (n = 111).
The co-primary outcomes were need for intubation and time to clinical recovery until day 28 as assessed by a 7-category ordinal scale (range, 1-7, with higher scores indicating a worse condition). Effects of treatments were calculated with a Cox proportional hazards model adjusted for hypoxemia severity, age, and comorbidities.
Among 220 randomized patients, 199 were included in the analysis (median age, 60 years; n = 65 women 32.7%). Intubation occurred in 34 (34.3%) randomized to high-flow oxygen therapy and in 51 (51.0%) randomized to conventional oxygen therapy (hazard ratio, 0.62; 95% CI, 0.39-0.96; P = .03). The median time to clinical recovery within 28 days was 11 (IQR, 9-14) days in patients randomized to high-flow oxygen therapy vs 14 (IQR, 11-19) days in those randomized to conventional oxygen therapy (hazard ratio, 1.39; 95% CI, 1.00-1.92; P = .047). Suspected bacterial pneumonia occurred in 13 patients (13.1%) randomized to high-flow oxygen and in 17 (17.0%) of those randomized to conventional oxygen therapy, while bacteremia was detected in 7 (7.1%) vs 11 (11.0%), respectively.
Among patients with severe COVID-19, use of high-flow oxygen through a nasal cannula significantly decreased need for mechanical ventilation support and time to clinical recovery compared with conventional low-flow oxygen therapy.
ClinicalTrials.gov Identifier: NCT04609462.
Background
Right dorsal colitis (RDC) is a nonsteroidal anti‐inflammatory drug (NSAID) induced, protein losing enteropathy in horses associated with a high case fatality rate.
Objectives
To describe ...signalment, NSAID usage, clinical presentations, clinical pathology, ultrasonographic findings, treatments, outcomes, and factors associated with survival in horses diagnosed with RDC.
Animals
Thirty‐five horses from 7 Australian equine hospitals diagnosed with RDC.
Methods
Retrospective case series. Clinical records of cases were accepted if definitively or presumptively diagnosed by an internist with RDC and had ≥3 of: hypoproteinemia or hypoalbuminemia; diarrhea with negative test results for infectious diseases; colic for which other diseases were excluded or right dorsal colon thickening on ultrasound. Descriptive data analysis was performed for categorical and continuous variables. Univariate binominal logistic regressions were used to assess factors associated with survival.
Results
An overdose of NSAIDs occurred in 84% (21/25) cases where dose was known. Common clinical presentations included diarrhea (69%; 22/32), colic (61%; 20/33), and tachycardia (53%, 17/32). Common clinicopathological findings included hypoalbuminemia (83%; 26/31), hypocalcaemia (79%, 23/29), and hyperlactatemia (77%, 14/18). The right dorsal colon wall appeared subjectively thickened in 77% (24/31) cases using ultrasonography. Case fatality rate was 43% (15/35). Odds of survival significantly decreased with increasing heart rate (odds 0.84, 95% CI = 0.71‐0.92, P = .01), packed cell volume (odds 0.91, 95% CI 0.82‐0.98, P = .05) and abnormal appearance of mucous membranes (odds 0.05, 95% CI 0.005‐0.28, P = .001) on hospital presentation.
Conclusions and Clinical Importance
An overdose of NSAIDs is common in horses diagnosed with RDC. Serum albumin concentrations should be monitored in horses receiving a prolonged course of NSAIDs. Overall prognosis for RDC remains fair.
We report the synthesis and biological evaluation of a ternary copper complex, Cu(5HTP)(phen)(H2O)(NO3).2H2O, with the antioxidant agent 5-hydroxytryptophan (5-HTP) and phenanthroline (phen, added to ...improve its lipophilicity and membrane transport). The crystal structure of the complex was determined by X-ray diffraction methods. The complex showed antioxidant, antimicrobial, antitumor and antimetastatic properties with an adequate safety profile. The interaction of the metal with phen promotes cellular copper accumulation and cytotoxicity on human lung A549 cell line (IC50 = 3.6 μM). Furthermore, the viability of the normal human fetal lung fibroblast cell line (MRC-5) is not altered by the complex. An oxidative stress mechanism for the anticancer effect has been determined: cellular increase of reactive oxygen species (ROS), decrease of the glutathione (GSH) and oxidized GSH (GSSG) ratio and alteration of the mitochondrial potential. The complex also displays antimetastatic activities with inhibition of cell adhesion, invasion and migration. It has not mutagenic behavior and no toxicity on Artemia salina indicating its potential to act as an effective and safety antimicrobial and antitumor drug.
Enhancement of lipophilicity and improvement of the biological effects of the binary copper(II)-5 hyrdoxytryptophan complex by phenanthroline complexation Display omitted
•Phenanthroline enhances lipophilicity of copper(II) 5-hydroxytryptophan complex.•Copper and reactive oxygen species (ROS) accumulation inside cells•Antioxidant, antimicrobial, anticancer and antimetastatic•No toxic against Artemia salina and normal lung cell lines; no mutagenicity•Effective and safety antimicrobial and antitumor drug
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