K2-265 b: a transiting rocky super-Earth Lam, K. W. F.; Santerne, A.; Sousa, S. G. ...
Astronomy and astrophysics (Berlin),
12/2018, Letnik:
620
Journal Article
Recenzirano
Odprti dostop
We report the discovery of the super-Earth K2-265 b detected with K2 photometry. The planet orbits a bright (Vmag = 11.1) star of spectral type G8V with a period of 2.37 days. We obtained ...high-precision follow-up radial velocity measurements from HARPS, and the joint Bayesian analysis showed that K2-265 b has a radius of 1.71 ± 0.11 R⊕ and a mass of 6.54 ± 0.84 M⊕, corresponding to a bulk density of 7.1 ± 1.8 g cm−3. Composition analysis of the planet reveals an Earth-like, rocky interior; this object has a rock mass fraction of ~80%. The short orbital period and small radius of the planet puts it below the lower limit of the photoevaporation gap, where the envelope of the planet could have eroded owing to strong stellar irradiation, leaving behind an exposed core. Knowledge of the planet core composition allows us to infer the possible formation and evolution mechanism responsible for its current physical parameters.
A broad range of viral and bacterial pathogens can cause acute respiratory tract infection. For rapid detection of a broad respiratory pathogen spectrum, multiplex real-time PCR is ideal. This study ...evaluated the performance of the new Luminex NxTAG Respiratory Pathogen Panel (NxTAG-RPP) in comparison with the BioFire FilmArray Respiratory Panel (FA-RP) or singleplex real-time PCR as reference. A total of 284 clinical respiratory specimens and 3 influenza A/H7N9 viral culture samples were tested. All clinical specimens were processed and analyzed in parallel using NxTAG-RPP and the reference standard method. The H7N9 viral culture samples were tested using NxTAG-RPP only. Overall, the NxTAG-RPP demonstrated ≥93% sensitivity and specificity for all respiratory targets except human coronavirus OC43 (HCoV-OC43) and HCoV-HKU1. The H7N9 virus was detected by the influenza A virus matrix gene target, while other influenza A virus subtyping gene targets in the panel remained negative. Complete concordance between NxTAG-RPP and FA-RP was observed in 98.8% (318/322) of positive results (kappa = 0.92). Substantial agreement was found for most respiratory targets, but significant differences were observed in human metapneumovirus (P = 0.001) and parainfluenza virus type 3 (P = 0.031). NxTAG-RPP has a higher sample throughput than FA-RP (96 samples versus 1 sample per run) while the turnaround times for NxTAG-RPP and FA-RP were 5 h (up to 96 samples) and 1 h (for one sample), respectively. Overall, NxTAG-RPP demonstrated good diagnostic performance for most respiratory pathogens. The high sample throughput with reasonable turnaround time of this new assay makes it a suitable multiplex platform for routine screening of respiratory specimens in hospital-based laboratories.
ABSTRACT
The chemical abundances of exoplanet atmospheres may provide valuable information about the bulk compositions, formation pathways, and evolutionary histories of planets. Exoplanets with ...large, relatively cloud-free atmospheres, and which orbit bright stars provide the best opportunities for accurate abundance measurements. For this reason, we measured the transmission spectrum of the bright (V ∼ 10.2), large (1.37 RJ), sub-Saturn mass (0.19 MJ) exoplanet WASP-127b across the near-UV to near-infrared wavelength range (0.3–5 μm), using the Hubble and Spitzer Space Telescopes. Our results show a feature-rich transmission spectrum, with absorption from Na, H2O, and CO2, and wavelength-dependent scattering from small-particle condensates. We ran two types of atmospheric retrieval models: one enforcing chemical equilibrium, and the other which fit the abundances freely. Our retrieved abundances at chemical equilibrium for Na, O, and C are all supersolar, with abundances relative to solar values of 9$^{+15}_{-6}$, 16$^{+7}_{-5}$, and 26$^{+12}_{-9}$, respectively. Despite giving conflicting C/O ratios, both retrievals gave supersolar CO2 volume mixing ratios, which adds to the likelihood that WASP-127b’s bulk metallicity is supersolar, since CO2 abundance is highly sensitive to atmospheric metallicity. We detect water at a significance of 13.7σ. Our detection of Na is in agreement with previous ground-based detections, though we find a much lower abundance, and we also do not find evidence for Li or K despite increased sensitivity. In the future, spectroscopy with James Webb Space Telescope will be able to constrain WASP-127b’s C/O ratio, and may reveal the formation history of this metal-enriched, highly observable exoplanet.
Aims. We have created a catalogue of variable stars found from a search of the publicly available K2 mission data from Campaigns 1 and 0. This catalogue provides the identifiers of 8395 variable ...stars, including 199 candidate eclipsing binaries with periods up to 60 d and 3871 periodic or quasi-periodic objects, with periods up to 20 d for Campaign 1 and 15 d for Campaign 0. Methods. Lightcurves are extracted and detrended from the available data. These are searched using a combination of algorithmic and human classification, leading to a classifier for each object as an eclipsing binary, sinusoidal periodic, quasi periodic, or aperiodic variable. The source of the variability is not identified, but could arise in the non-eclipsing binary cases from pulsation or stellar activity. Each object is cross-matched against variable star related guest observer proposals to the K2 mission, which specifies the variable type in some cases. The detrended lightcurves are also compared to lightcurves currently publicly available. Results. The resulting catalogue gives the ID, type, period, semi-amplitude, and range of the variation seen. We also make available the detrended lightcurves for each object.
Aims
To assess whether a structured diabetes education programme, the Patient Empowerment Programme (PEP), was associated with a lower risk of first cardiovascular disease (CVD) event and all‐cause ...mortality in a population‐based cohort of patients with type 2 diabetes mellitus (T2DM) in primary care.
Methods
A Chinese cohort of 27 278 patients with T2DM and without previous CVD events on or before the baseline study recruitment date was linked to the Hong Kong administrative database from 2008 to 2013. The PEP was provided to patients with T2DM treated at primary care outpatient clinics through community trained professional educators. PEP non‐participants were matched one‐to‐one with the PEP participants using a propensity score method with respect to their baseline covariates. Cox proportional hazard regression was performed to estimate the associations of the PEP with the occurrence of first CVD event, coronary heart disease, stroke, heart failure and death from any cause, controlling for baseline characteristics.
Results
During a median of 21.5 months follow‐up, 795 (352 PEP participants and 443 PEP non‐participants) patients experienced a first CVD event. After adjusting for confounding variables, PEP participants had a lower rate of all‐cause mortality hazard ratio (HR) 0.564, 95% confidence interval (CI) 0.445–0.715; p < 0.001, first CVD (HR 0.807, 95% CI 0.696–0.935; p = 0.004) and stroke (HR 0.702; 95% CI 0.569–0.867; p = 0.001) than those without PEP.
Conclusions
Enrolment in the PEP was associated with lower all‐cause mortality and a lower number of first CVD events among patients with T2DM. The CVD benefit of PEP might be attributable to improving metabolic control through empowerment of self‐care and the enhancement of quality of diabetes care in primary care.
While dromedaries are the immediate animal source of Middle East Respiratory Syndrome (MERS) epidemic, viruses related to MERS coronavirus (MERS-CoV) have also been found in bats as well as ...hedgehogs. To elucidate the evolution of MERS-CoV-related viruses and their interspecies transmission pathway, samples were collected from different mammals in China. A novel coronavirus related to MERS-CoV,
hedgehog coronavirus HKU31 (
-HedCoV HKU31), was identified from two Amur hedgehogs. Genome analysis supported that
-HedCoV HKU31 represents a novel species under
, being most closely related to
CoV from European hedgehogs in Germany, with 79.6% genome sequence identity. Compared to other members of
,
-HedCoV HKU31 possessed unique non-structural proteins and putative cleavage sites at ORF1ab. Phylogenetic analysis showed that
-HedCoV HKU31 and BetaCoV Erinaceus/VMC/DEU/2012 were closely related to NeoCoV and BatCoV PREDICT from African bats in the spike region, suggesting that the latter bat viruses have arisen from recombination between CoVs from hedgehogs and bats. The predicted HKU31 receptor-binding domain (RBD) possessed only one out of 12 critical amino acid residues for binding to human dipeptidyl peptidase 4 (hDPP4), the MERS-CoV receptor. The structural modeling of the HKU31-RBD-hDPP4 binding interphase compared to that of MERS-CoV and
bat CoV HKU4 (
-BatCoV HKU4) suggested that HKU31-RBD is unlikely to bind to hDPP4. Our findings support that hedgehogs are an important reservoir of
, with evidence of recombination with viruses from bats. Further investigations in bats, hedgehogs and related animals are warranted to understand the evolution of MERS-CoV-related viruses.
The Forkhead box transcription factor FoxM1 is expressed in proliferating cells. When it was depleted in mice and cell lines, cell cycle defects and chromosomal instability resulted. Premature ...senescence was observed in embryonic fibroblasts derived from FoxM1 knock-out mice, but the underlying cause has remained unclear. To investigate whether FoxM1 can protect cells against stress-induced premature senescence, we established NIH3T3 lines with doxycycline-inducible overexpression of FoxM1c. Treatment of these lines with sublethal doses (20 and 100 μm) of H2O2 induced senescence with senescence-associated β-galactosidase expression and elevated levels of p53 and p21. Induction of FoxM1c expression markedly suppressed senescence and expression of p53 and p21. Consistent with down-regulation of the p19Arf-p53 pathway, p19Arf levels decreased while expression of the Polycomb group protein Bmi-1 was induced. That Bmi-1 is a downstream target of FoxM1c was further supported by the dose-dependent induction of Bmi-1 by FoxM1c at both the protein and mRNA levels, and FoxM1 and Bmi-1 reached maximal levels in cells at the G2/M phase. Depletion of FoxM1 by RNA interference decreased Bmi-1 expression. Using Bmi-1 promoter reporters with wild-type and mutated c-Myc binding sites and short hairpin RNAs targeting c-Myc, we further demonstrated that FoxM1c activated Bmi-1 expression via c-Myc, which was recently reported to be regulated by FoxM1c. Our results reveal a functional link between FoxM1c, c-Myc, and Bmi-1, which are major regulators of tumorigenesis. This link has important implications for the regulation of cell proliferation and senescence by FoxM1 and Bmi-1.
We report the discovery of a super-Earth and a sub-Neptune transiting the star HD 15337 (TOI-402, TIC 120896927), a bright (V = 9) K1 dwarf observed by the Transiting Exoplanet Survey Satellite ...(TESS) in Sectors 3 and 4. We combine the TESS photometry with archival High Accuracy Radial velocity Planet Searcher spectra to confirm the planetary nature of the transit signals and derive the masses of the two transiting planets. With an orbital period of 4.8 days, a mass of and a radius of 1.64 0.06 R⊕, HD 15337 b joins the growing group of short-period super-Earths known to have a rocky terrestrial composition. The sub-Neptune HD 15337 c has an orbital period of 17.2 days, a mass of , and a radius of 2.39 0.12 R⊕, suggesting that the planet might be surrounded by a thick atmospheric envelope. The two planets have similar masses and lie on opposite sides of the radius gap, and are thus an excellent testbed for planet formation and evolution theories. Assuming that HD 15337 c hosts a hydrogen-dominated envelope, we employ a recently developed planet atmospheric evolution algorithm in a Bayesian framework to estimate the history of the high-energy (extreme ultraviolet and X-ray) emission of the host star. We find that at an age of 150 Myr, the star possessed on average between 3.7 and 127 times the high-energy luminosity of the current Sun.
TOI-1416 (BD+42 2504, HIP 70705) is a
V
=10 late G- or early K-type dwarf star. TESS detected transits in its Sectors 16, 23, and 50 with a depth of about 455 ppm and a period of 1.07 days. Radial ...velocities (RVs) confirm the presence of the transiting planet TOI-1416
b
, which has a mass of 3.48 ± 0.47
M
⊕
and a radius of 1.62 ± 0.08
R
⊕
, implying a slightly sub-Earth density of 4.50
−0.83
+0.99
g cm
−3
. The RV data also further indicate a tentative planet,
c
, with a period of 27.4 or 29.5 days, whose nature cannot be verified due to strong suspicions of contamination by a signal related to the Moon’s synodic period of 29.53 days. The nearly ultra-short-period planet TOI-1416
b
is a typical representative of a short-period and hot (
T
eq
≈ 1570 K) super-Earth-like planet. A planet model of an interior of molten magma containing a significant fraction of dissolved water provides a plausible explanation for its composition, and its atmosphere could be suitable for transmission spectroscopy with JWST. The position of TOI-1416
b
within the radius-period distribution corroborates the idea that planets with periods of less than one day do not form any special group. It instead implies that ultra-short-period planets belong to a continuous distribution of super-Earth-like planets with periods ranging from the shortest known ones up to ≈30 days; their period-radius distribution is delimited against larger radii by the Neptune Desert and by the period-radius valley that separates super-Earths from sub-Neptune planets. In the abundance of small, short-periodic planets, a notable plateau has emerged between periods of 0.6–1.4 days, which is compatible with the low-eccentricity formation channel. For the Neptune Desert, its lower limits required a revision due to the increasing population of short-period planets; for periods shorter then 2 days, we establish a radius of 1.6
R
⊕
and a mass of 0.028
M
jup
(corresponding to 8.9
M
⊕
) as the desert’s lower limits. We also provide corresponding limits to the Neptune Desert against the planets’ insolation and effective temperatures.
Long non-coding RNAs (lncRNAs) play a pivotal role in tumorigenesis, exemplified by the recent finding that lncRNA maternally expressed gene 3 (MEG3) inhibits tumor growth in a p53-dependent manner. ...Acute myeloid leukemia (AML) is the most common malignant myeloid disorder in adults, and TP53 mutations or loss are frequently detected in patients with therapy-related AML or AML with complex karyotype. Here, we reveal that MEG3 is significantly downregulated in AML and suppresses leukemogenesis not only in a p53-dependent, but also a p53-independent manner. In addition, MEG3 is proven to be transcriptionally activated by Wilms' tumor 1 (WT1), dysregulation of which by epigenetic silencing or mutations is causally involved in AML. Therefore MEG3 is identified as a novel target of the WT1 molecule. Ten-eleven translocation-2 (TET2) mutations frequently occur in AML and significantly promote leukemogenesis of this disorder. In our study, TET2, acting as a cofactor of WT1, increases MEG3 expression. Taken together, our work demonstrates that TET2 dysregulated WT1-MEG3 axis significantly promotes AML leukemogenesis, paving a new avenue for diagnosis and treatment of AML patients.
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