We present a new Y dwarf, WISE J030449.03−270508.3, confirmed from a candidate sample designed to pick out low-temperature objects from the Wide-field Infrared Survey Explorer (WISE) data base. The ...new object is typed Y0pec following a visual comparison with spectral standards, and lies at a likely distance of 10–17 pc. Its tangential velocity suggests thin disc membership, but it shows some spectral characteristics that suggest that it may be metal poor and/or older than previously identified Y0 dwarfs. Based on trends seen for warmer late-type T dwarfs, the Y-band flux peak morphology is indicative of sub-solar metallicity, and the enhanced red wing of the J-band flux peak offers evidence for high gravity and/or low metallicity (with associated model trends suggesting an age closer to ∼10 Gyr and mass in the range 0.02–0.03 M⊙). This object may thus be extending the population parameter space of the known Y0 dwarfs.
We identify 806 ultracool dwarfs (of which 34 are newly discovered L dwarfs) from their Sloan Digital Sky Survey (SDSS) riz photometry and obtain proper motions through cross-matching with the United ...Kingdom Infrared Telescope Infrared Deep Sky Survey (UKIDSS) and Two-Micron All-Sky Survey (2MASS). Proper-motion and distance constraints show that nine of our ultracool dwarfs are members of widely separated binary systems: SDSS 0101 (K5V+M9.5V), SDSS 0207 (M1.5V+L3V), SDSS 0832 (K3III+L3.5V), SDSS 0858 (M4V+L0V), SDSS 0953 (M4V+M9.5V), SDSS 0956 (M2V+M9V), SDSS 1304 (M4.5V+L0V), SDSS 1631 (M5.5V+M8V) and SDSS 1638 (M4V+L0V). One of these (SDSS 0832) is shown to be a companion to the bright K3 giant η Cancri. Such primaries can provide age and metallicity constraints for any companion objects, yielding excellent benchmark objects. η Cancri AB is the first wide ultracool dwarf + giant binary system identified. We present new observations and analysis that constrain the metallicity of η Cancri A to be near-solar, and use recent evolutionary models to constrain the age of the giant to be 2.2–6.1 Gyr. If η Cancri B is a single object, we estimate its physical attributes to be mass = 63–82 MJup, Teff= 1800 ± 150 K, log g= 5.3–5.5, M/H= 0.0 ± 0.1. Its colours are non-typical when compared with other ultracool dwarfs, and we also assess the possibility that η Cancri B is itself an unresolved binary, showing that the combined light of an L4 + T4 system could provide a reasonable explanation for its colours.
ABSTRACT
We present an ultra‐cool dwarf (UCD) catalogue compiled from low southern Galactic latitudes and mid‐plane, from a cross‐correlation of the Two Micron All‐Sky Survey (2MASS) and the ...SuperCOSMOS survey. The catalogue contains 246 members identified from 5042 deg2 within 220° ≤ ℓ ≤ 360° and 0° < ℓ ≤ 30°, for |b| ≤ 15°. Sixteen candidates are spectroscopically confirmed in the near‐infrared as UCDs with spectral types from M7.5V to L9, the latest being the unusual blue L dwarf 2MASS J11263991−5003550. Our catalogue selection method is presented enabling UCDs from ∼M8V to the L–T transition to be selected down to a 2MASS limiting magnitude of Ks≃14.5 mag (for S/N ≥ 10). This method does not require candidates to have optical detections for catalogue inclusion. An optimal set of optical/near‐IR and reduced proper‐motion selection criteria have been defined that includes: an RF and IN photometric surface gravity test; a dual RF‐band variability check and an additional photometric classification scheme to selectively limit numbers of potential contaminants in regions of severe overcrowding. We identify four candidates as possible companions to nearby Hipparcos stars – observations are needed to identify these as potential benchmark UCD companions. We also identify 12 UCDs within a possible distance 20 pc, three are previously unknown of which two are estimated within 10 pc, complementing the nearby volume‐limited census of UCDs. An analysis of the catalogue spatial completeness provides estimates for distance completeness over three UCD MJ ranges, while Monte Carlo simulations provide an estimate of catalogue areal completeness at the 75 per cent level. We estimate a UCD space density of ρ(total) = (6.41 ± 3.01) × 10−3 pc−3 over the range of 10.5≤MJ≲14.9, similar to values measured at higher Galactic latitudes (|b|≳10∘) in the field population and obtained from more robust spectroscopically confirmed UCD samples.
Background
Trichomoniasis commonly affects women of childbearing age and has been linked to several adverse birth outcomes.
Objective
To elucidate the association between trichomoniasis in pregnant ...women and adverse birth outcomes, including preterm delivery, prelabour rupture of membranes and low birthweight.
Search strategy
MEDLINE, EMBASE and ClinicalTrials.gov were systematically searched in December 2020 without time or language restrictions.
Selection criteria
Original research studies were included if they assessed at least one of the specified adverse birth outcomes in pregnant women with laboratory‐diagnosed trichomoniasis.
Data collection and analysis
Estimates from included articles were either extracted or calculated and then pooled to produce a combined estimate of the association of trichomoniasis with each adverse birth outcome using the random effects model. Heterogeneity was assessed using the I2 statistic and Cochran's Q test.
Main results
Literature search produced 1658 publications after removal of duplicates (n = 770), with five additional publications identified by hand search. After screening titles and s for relevance, full text of 84 studies was reviewed and 19 met inclusion criteria for meta‐analysis. Significant associations were found between trichomoniasis and preterm delivery (OR 1.27; 95% CI 1.08–1.50), prelabour rupture of membranes (OR 1.87; 95% CI 1.53–2.29) and low birthweight (OR 2.12; 95% CI 1.15–3.91).
Conclusions
Trichomoniasis in pregnant women is associated with preterm delivery, prelabour rupture of membranes and low birthweight. Rigorous studies are needed to determine the impact of universal trichomoniasis screening and treatment during pregnancy on reducing perinatal morbidity.
Tweetable
This systematic review and meta‐analysis found that in the setting of pregnancy, trichomoniasis is significantly associated with multiple adverse birth outcomes, including preterm delivery, low birthweight, and prelabour rupture of membranes.
Tweetable
This systematic review and meta‐analysis found that in the setting of pregnancy, trichomoniasis is significantly associated with multiple adverse birth outcomes, including preterm delivery, low birthweight, and prelabour rupture of membranes.
Over 30 mutations of the
B-RAF gene associated with human cancers have been identified, the majority of which are located within the kinase domain. Here we show that of 22 B-RAF mutants analyzed, 18 ...have elevated kinase activity and signal to ERK in vivo. Surprisingly, three mutants have reduced kinase activity towards MEK in vitro but, by activating C-RAF in vivo, signal to ERK in cells. The structures of wild type and oncogenic
V599EB-RAF kinase domains in complex with the RAF inhibitor BAY43-9006 show that the activation segment is held in an inactive conformation by association with the P loop. The clustering of most mutations to these two regions suggests that disruption of this interaction converts B-RAF into its active conformation. The high activity mutants signal to ERK by directly phosphorylating MEK, whereas the impaired activity mutants stimulate MEK by activating endogenous C-RAF, possibly via an allosteric or transphosphorylation mechanism.
Older adults with diabetes are at high risk of severe hypoglycemia (SH). Many machine-learning (ML) models predict short-term hypoglycemia are not specific for older adults and show poor ...precision-recall. We aimed to develop a multidimensional, electronic health record (EHR)-based ML model to predict one-year risk of SH requiring hospitalization in older adults with diabetes.
We adopted a case-control design for a retrospective territory-wide cohort of 1,456,618 records from 364,863 unique older adults (age ≥65 years) with diabetes and at least 1 Hong Kong Hospital Authority attendance from 2013 to 2018. We used 258 predictors including demographics, admissions, diagnoses, medications, and routine laboratory tests in a one-year period to predict SH events requiring hospitalization in the following 12 months. The cohort was randomly split into training, testing, and internal validation sets in a 7:2:1 ratio. Six ML algorithms were evaluated including logistic-regression, random forest, gradient boost machine, deep neural network (DNN), XGBoost, and Rulefit. We tested our model in a temporal validation cohort in the Hong Kong Diabetes Register with predictors defined in 2018 and outcome events defined in 2019. Predictive performance was assessed using area under the receiver operating characteristic curve (AUROC), area under the precision-recall curve (AUPRC) statistics, and positive predictive value (PPV). We identified 11,128 SH events requiring hospitalization during the observation periods. The XGBoost model yielded the best performance (AUROC = 0.978 95% CI 0.972 to 0.984; AUPRC = 0.670 95% CI 0.652 to 0.688; PPV = 0.721 95% CI 0.703 to 0.739). This was superior to an 11-variable conventional logistic-regression model comprised of age, sex, history of SH, hypertension, blood glucose, kidney function measurements, and use of oral glucose-lowering drugs (GLDs) (AUROC = 0.906; AUPRC = 0.085; PPV = 0.468). Top impactful predictors included non-use of lipid-regulating drugs, in-patient admission, urgent emergency triage, insulin use, and history of SH. External validation in the HKDR cohort yielded AUROC of 0.856 95% CI 0.838 to 0.873. Main limitations of this study included limited transportability of the model and lack of geographically independent validation.
Our novel-ML model demonstrated good discrimination and high precision in predicting one-year risk of SH requiring hospitalization. This may be integrated into EHR decision support systems for preemptive intervention in older adults at highest risk.
Osteosarcoma (OS) is the most frequent pediatric malignant bone tumor that has a high propensity for metastases. Through osteoblast-specific alteration of p53 status, we developed a genetically ...engineered mouse model of localized and metastatic OS to gain an understanding into the molecular pathogenesis of OS. Microarray analysis of both localized tumors and metastatic tumors identified the downregulation of the naked cuticle homolog 2 (NKD2) gene, a negative regulator of Wnt signaling. Overexpression of NKD2 in metastatic human and mouse OS cells significantly decreases cell proliferation, migration and invasion ability in vitro and drastically diminishes OS tumor growth and metastasis in vivo, whereas downregulation enhances migratory and invasive potential. Evaluation of NKD2-overexpressing tumors revealed upregulation of tumor-suppressor genes and downregulation of molecules involved in blood vessel formation and cell migration. Furthermore, assessment of primary human OS revealed downregulation of NKD2 in metastatic and recurrent OS. Finally, we provide biological evidence that use of small-molecule inhibitors targeting the Wnt pathway can have therapeutic efficacy in decreasing metastatic properties in OS. Our studies provide compelling evidence that downregulation of NKD2 expression and alterations in associated regulated pathways have a significant role in driving OS tumor growth and metastasis.
ABSTRACT
During a 2018 outburst, the black hole X-ray binary MAXI J1820 + 070 was comprehensively monitored at multiple wavelengths as it underwent a hard to soft state transition. During this ...transition, a rapid evolution in X-ray timing properties and a short-lived radio flare were observed, both of which were linked to the launching of bi-polar, long-lived relativistic ejecta. We provide a detailed analysis of two Very Long Baseline Array observations, using both time binning and a new dynamic phase centre tracking technique to mitigate the effects of smearing when observing fast-moving ejecta at high angular resolution. We identify a second, earlier ejection, with a lower proper motion of 18.0 ± 1.1 mas d−1. This new jet knot was ejected 4 ± 1 h before the beginning of the rise of the radio flare, and 2 ± 1 h before a switch from type-C to type-B X-ray quasi-periodic oscillations (QPOs). We show that this jet was ejected over a period of ∼6 h and thus its ejection was contemporaneous with the QPO transition. Our new technique locates the original, faster ejection in an observation in which it was previously undetected. With this detection, we revised the fits to the proper motions of the ejecta and calculated a jet inclination angle of (64 ± 5)°, and jet velocities of $0.97_{-0.09}^{+0.03}c$ for the fast-moving ejecta (Γ > 2.1) and (0.30 ± 0.05)c for the newly identified slow-moving ejection (Γ = 1.05 ± 0.02). We show that the approaching slow-moving component is predominantly responsible for the radio flare, and is likely linked to the switch from type-C to type-B QPOs, while no definitive signature of ejection was identified for the fast-moving ejecta.
Global peatlands store more carbon than is naturally present in the atmosphere
. However, many peatlands are under pressure from drainage-based agriculture, plantation development and fire, with the ...equivalent of around 3 per cent of all anthropogenic greenhouse gases emitted from drained peatland
. Efforts to curb such emissions are intensifying through the conservation of undrained peatlands and re-wetting of drained systems
. Here we report eddy covariance data for carbon dioxide from 16 locations and static chamber measurements for methane from 41 locations in the UK and Ireland. We combine these with published data from sites across all major peatland biomes. We find that the mean annual effective water table depth (WTD
; that is, the average depth of the aerated peat layer) overrides all other ecosystem- and management-related controls on greenhouse gas fluxes. We estimate that every 10 centimetres of reduction in WTD
could reduce the net warming impact of CO
and CH
emissions (100-year global warming potentials) by the equivalent of at least 3 tonnes of CO
per hectare per year, until WTD
is less than 30 centimetres. Raising water levels further would continue to have a net cooling effect until WTD
is within 10 centimetres of the surface. Our results suggest that greenhouse gas emissions from peatlands drained for agriculture could be greatly reduced without necessarily halting their productive use. Halving WTD
in all drained agricultural peatlands, for example, could reduce emissions by the equivalent of over 1 per cent of global anthropogenic emissions.
The rest-frame ultraviolet properties of galaxies during the first three billion years of cosmic time (redshift z > 4) indicate a rapid evolution in the dust obscuration of such galaxies. This ...evolution implies a change in the average properties of the interstellar medium, but the measurements are systematically uncertain owing to untested assumptions and the inability to detect heavily obscured regions of the galaxies. Previous attempts to measure the interstellar medium directly in normal galaxies at these redshifts have failed for a number of reasons, with two notable exceptions. Here we report measurements of the forbidden C ii emission (that is, C II) from gas, and the far-infrared emission from dust, in nine typical star-forming galaxies about one billion years after the Big Bang (z ≈ 5-6). We find that these galaxies have thermal emission that is less than 1/12 that of similar systems about two billion years later, and enhanced C II emission relative to the far-infrared continuum, confirming a strong evolution in the properties of the interstellar medium in the early Universe. The gas is distributed over scales of one to eight kiloparsecs, and shows diverse dynamics within the sample. These results are consistent with early galaxies having significantly less dust than typical galaxies seen at z < 3 and being comparable in dust content to local low-metallicity systems.
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