Abstract
We report the discovery of a circumplanetary disk (CPD) candidate embedded in the circumstellar disk of the T Tauri star AS 209 at a radial distance of about 200 au (on-sky separation of ...1.″4 from the star at a position angle of 161°), isolated via
13
CO
J
= 2−1 emission. This is the first instance of CPD detection via gaseous emission capable of tracing the overall CPD mass. The CPD is spatially unresolved with a 117 × 82 mas beam and manifests as a point source in
13
CO, indicating that its diameter is ≲14 au. The CPD is embedded within an annular gap in the circumstellar disk previously identified using
12
CO and near-infrared scattered-light observations and is associated with localized velocity perturbations in
12
CO. The coincidence of these features suggests that they have a common origin: an embedded giant planet. We use the
13
CO intensity to constrain the CPD gas temperature and mass. We find that the CPD temperature is ≳35 K, higher than the circumstellar disk temperature at the radial location of the CPD, 22 K, suggesting that heating sources localized to the CPD must be present. The CPD gas mass is ≳0.095
M
Jup
≃ 30
M
⊕
adopting a standard
13
CO abundance. From the nondetection of millimeter continuum emission at the location of the CPD (3
σ
flux density ≲26.4
μ
Jy), we infer that the CPD dust mass is ≲0.027
M
⊕
≃ 2.2 lunar masses, indicating a low dust-to-gas mass ratio of ≲9 × 10
−4
. We discuss the formation mechanism of the CPD-hosting giant planet on a wide orbit in the framework of gravitational instability and pebble accretion.
ABSTRACT
We study the morphology of the stellar periphery of the Magellanic Clouds in search of substructure using near-infrared imaging data from the Visible and Infrared Survey Telescope for ...Astronomy Hemisphere Survey. Based on the selection of different stellar populations using the (J − Ks, Ks) colour–magnitude diagram, we confirm the presence of substructures related to the interaction history of the Clouds and find new substructures on the eastern side of the LMC disc, which may be owing to the influence of the Milky Way, and on the northern side of the SMC, which is probably associated with the ellipsoidal structure of the galaxy. We also study the luminosity function of red clump stars in the SMC and confirm the presence of a bi-modal distance distribution, in the form of a foreground population. We find that this bi-modality is still detectable in the eastern regions of the galaxy out to a 10○ distance from its centre. Additionally, a background structure is detected in the North between 7○ and 10○ from the centre that might belong to the Counter Bridge, and a foreground structure is detected in the South between 6○ and 8○ from the centre that might be linked to the Old Bridge.
Background. Each year, Bordetella pertussis infection causes an estimated 294,000 deaths worldwide, primarily among young, nonvaccinated children. Approximately 90% of all deaths due to pertussis in ...the Unites States occur in young infants. These children often develop intractable pulmonary hypertension; however, the pathophysiologic mechanism responsible for this complication has not been well characterized, and there have been no detailed descriptions of the pathology of this disease since the 1940s. Methods. Respiratory tissue samples obtained at autopsy from 15 infants aged ⩽4 months who had polymerase chain reaction- or culture-confirmed B. pertussis pneumonia were evaluated by multiple histochemical stains, immunohistochemical evaluation, and electron microscopic examination. Results. The pulmonary histopathologic examination of the samples revealed a descending infection dominated by necrotizing bronchiolitis, intra-alveolar hemorrhage, and fibrinous edema. All samples had marked leukocytosis, and most showed luminal aggregates of abundant leukocytes in small pulmonary arteries, veins, and lymphatics. A novel immunohistochemical stain for B. pertussis revealed abundant extracellular bordetellae in cilia of the trachea, bronchi, and bronchioles, as well as intracellular bacteria and antigens in alveolar macrophages and ciliated epithelium. Conclusions. Pertussis should be suspected in any infant death associated with marked leukocytosis, bronchopneumonia, or refractory pulmonary hypertension, particularly in children aged ⩽4 months. The pathologic findings identified in the respiratory tracts of these children, in addition to recognized physiologic responses of the infant lung to hypoxia, suggest that B. pertussis pneumonia triggers a cascade of events that includes acute pulmonary vasoconstriction and pertussis toxin-mediated increases in circulating leukocyte mass. These responses ultimately compromise pulmonary blood flow, exacerbate hypoxemia, and create a vicious cycle of refractory pulmonary hypertension.
Przewalski’s horses (PHs, Equus ferus ssp. przewalskii) were discovered in the Asian steppes in the 1870s and represent the last remaining true wild horses. PHs became extinct in the wild in the ...1960s but survived in captivity, thanks to major conservation efforts. The current population is still endangered, with just 2,109 individuals, one-quarter of which are in Chinese and Mongolian reintroduction reserves 1. These horses descend from a founding population of 12 wild-caught PHs and possibly up to four domesticated individuals 2–4. With a stocky build, an erect mane, and stripped and short legs, they are phenotypically and behaviorally distinct from domesticated horses (DHs, Equus caballus). Here, we sequenced the complete genomes of 11 PHs, representing all founding lineages, and five historical specimens dated to 1878–1929 CE, including the Holotype. These were compared to the hitherto-most-extensive genome dataset characterized for horses, comprising 21 new genomes. We found that loci showing the most genetic differentiation with DHs were enriched in genes involved in metabolism, cardiac disorders, muscle contraction, reproduction, behavior, and signaling pathways. We also show that DH and PH populations split ∼45,000 years ago and have remained connected by gene-flow thereafter. Finally, we monitor the genomic impact of ∼110 years of captivity, revealing reduced heterozygosity, increased inbreeding, and variable introgression of domestic alleles, ranging from non-detectable to as much as 31.1%. This, together with the identification of ancestry informative markers and corrections to the International Studbook, establishes a framework for evaluating the persistence of genetic variation in future reintroduced populations.
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•Complete genomes were sequenced for 21 domesticated and 17 Przewalski’s horses•Selection signatures and variants specific to Przewalski’s horses were detected•Domesticated and Przewalski’s horse ancestors mixed post-divergence ∼45,000 years ago•Captivity increased inbreeding and domestic introgression in Przewalski’s horses
Der Sarkissian et al. characterized complete genomes of modern and historical Przewalski’s horses, a wild and endangered population distinct from domesticated horses. Comparative analyses revealed specific signatures of selection, increased inbreeding, and variable introgression from domesticated horses in the last 110 years in captivity.
ABSTRACT The rate of image acquisition in modern synoptic imaging surveys has already begun to outpace the feasibility of keeping astronomers in the real-time discovery and classification loop. Here ...we present the inner workings of a framework, based on machine-learning algorithms, that captures expert training and ground-truth knowledge about the variable and transient sky to automate (1) the process of discovery on image differences, and (2) the generation of preliminary science-type classifications of discovered sources. Since follow-up resources for extracting novel science from fast-changing transients are precious, self-calibrating classification probabilities must be couched in terms of efficiencies for discovery and purity of the samples generated. We estimate the purity and efficiency in identifying real sources with a two-epoch image-difference discovery algorithm for the Palomar Transient Factory (PTF) survey. Once given a source discovery, using machine-learned classification trained on PTF data, we distinguish between transients and variable stars with a 3.8% overall error rate (with 1.7% errors for imaging within the Sloan Digital Sky Survey footprint). At >96% classification efficiency, the samples achieve 90% purity. Initial classifications are shown to rely primarily on context-based features, determined from the data itself and external archival databases. In the first year of autonomous operations of PTF, this discovery and classification framework led to several significant science results, from outbursting young stars to subluminous Type IIP supernovae to candidate tidal disruption events. We discuss future directions of this approach, including the possible roles of crowdsourcing and the scalability of machine learning to future surveys such as the Large Synoptic Survey Telescope (LSST).
Phytochemicals exert antiviral activity and may play a potential therapeutic role in hepatitis C virus (HCV) infection. In this work, we aimed to isolate NS3 inhibitors from traditional Indian ...medicinal plants that were found, in our earlier study, to inhibit HCV NS3 protease activity and to evaluate their potential to inhibit HCV replication. A potent inhibitory effect of NS3 catalytic activity was obtained with Embelia ribes plant extracts. Quercetin, a ubiquitous plant flavonoid, was identified as the active substance in the fractioned extract. It was found to inhibit NS3 activity in a specific dose‐dependent manner in an in vitro catalysis assay. Quercetin inhibited HCV RNA replication as analysed in the subgenomic HCV RNA replicon system. It also inhibited HCV infectious virus production in the HCV infectious cell culture system (HCVcc), as analysed by the focus‐forming unit reduction assay and HCV RNA real‐time PCR. The inhibitory effect of quercetin was also obtained when using a model system in which NS3 engineered substrates were introduced in NS3‐expressing cells, providing evidence that inhibition in vivo could be directed to the NS3 and do not involve other HCV proteins. Our work demonstrates that quercetin has a direct inhibitory effect on the HCV NS3 protease. These results point to the potential of quercetin as a natural nontoxic anti‐HCV agent reducing viral production by inhibiting both NS3 and heat shock proteins essential for HCV replication.
ABSTRACT
We present a sample of 14 hydrogen-rich superluminous supernovae (SLSNe II) from the Zwicky Transient Facility (ZTF) between 2018 and 2020. We include all classified SLSNe with peaks Mg < ...−20 mag with observed broad but not narrow Balmer emission, corresponding to roughly 20 per cent of all hydrogen-rich SLSNe in ZTF phase I. We examine the light curves and spectra of SLSNe II and attempt to constrain their power source using light-curve models. The brightest events are photometrically and spectroscopically similar to the prototypical SN 2008es, while others are found spectroscopically more reminiscent of non-superluminous SNe II, especially SNe II-L. 56Ni decay as the primary power source is ruled out. Light-curve models generally cannot distinguish between circumstellar interaction (CSI) and a magnetar central engine, but an excess of ultraviolet (UV) emission signifying CSI is seen in most of the SNe with UV data, at a wide range of photometric properties. Simultaneously, the broad H α profiles of the brightest SLSNe II can be explained through electron scattering in a symmetric circumstellar medium (CSM). In other SLSNe II without narrow lines, the CSM may be confined and wholly overrun by the ejecta. CSI, possibly involving mass lost in recent eruptions, is implied to be the dominant power source in most SLSNe II, and the diversity in properties is likely the result of different mass loss histories. Based on their radiated energy, an additional power source may be required for the brightest SLSNe II, however – possibly a central engine combined with CSI.
The use of copper intrauterine contraceptive devices is currently limited to 2-3 years, mainly due to wire fragmentation, which was observed as early as after 8 months of use. In the resulting search ...for a long-lasting device, two new systems of duplex wire, with gold and platinum cores electrolytically coated with copper, were devised and studied. Initially, duplex wires and controls were exposed to physiological solution. Copper dissolution rate, and corrosion morphology were studied by weight-loss measurements and optical metallography. Similar systems were then surgically implanted in rat uteri for varying periods up to 26 weeks. Electron microanalysis of corrosion products in addition to weight-loss measurements and metallography was performed. The results showed that a uniform and ductile copper coating is obtainable by electroplating on gold and platinum wires. The rate of copper dissolution is similar to that of solid copper wire. No dissolution of gold and platinum in the controls or coated wires was detected by weight loss, metallography or atomic absorption measurements. Microanalysis of the deposits and corrosion products on the wires in the uterine environment showed the presence of compounds containing sulphur, chlorine, calcium and copper. The results of this study suggest that supplementing IUDs with copper-coated gold or platinum wires may result in significant prolongation of the life-span of the device by preventing uncontrolled loss of copper caused by wire fragmentation.
Objective To examine the incidence of pediatric congenital hearing loss and the timing of diagnosis in a rural region of hearing healthcare disparity. Study design Data from the Kentucky newborn ...hearing-screening program was accessed to determine the incidence of congenital hearing loss in Kentucky, both in the extremely rural region of Appalachia and non-Appalachian region of Kentucky. We also performed a retrospective review of records of children with congenital hearing loss at our institution to determine the timing of diagnostic testing. Results In Kentucky, during 2009-2011, there were 6970 newborns who failed hearing screening; the incidence of newborn hearing loss was 1.71 per 1000 births (1.28/1000 in Appalachia and 1.87/1000 in non-Appalachia); 23.8% of Appalachian newborns compared with 17.3% of non-Appalachian children failed to obtain follow-up diagnostic testing. Children from Appalachia were significantly delayed in obtaining a final diagnosis of hearing loss compared with children from non-Appalachian regions ( P = .04). Conclusion Congenital hearing loss in children from rural regions with hearing healthcare disparities is a common problem, and these children are at risk for a delay in the timing of diagnosis, which has the potential to limit language and social development. It is important to further assess the causative factors and develop interventions that can address this hearing healthcare disparity issue.
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