36 research outputs found
WASP 1628+10-an EL CVn-type binary with a very low mass stripped red giant star and multiperiodic pulsations
The star 1SWASP J162842.31+101416.7 (WASP 1628+10) is one of several EL CVn-type
stars recently identified using the Wide Angle Search for Planets (WASP) data base, i.e. an
eclipsing binary star in which an A-type dwarf star (WASP 1628+10 A) eclipses the remnant
of a disrupted red giant star (WASP 1628+10 B). We have measured the masses, radii and
luminosities of the stars in WASP 1628+10 using photometry obtained in three bands (u
,
g
, r
) with the ULTRACAM instrument and medium-resolution spectroscopy. The properties
of the remnant are well matched by models for stars in a rarely observed state evolving to
higher effective temperatures at nearly constant luminosity prior to becoming a very low mass
white dwarf composed almost entirely of helium, i.e. we confirm that WASP 1628+10 B
is a precursor of a helium white dwarf (pre-He-WD). WASP 1628+10 A appears to be a
normal A2 V star with a mass of 1.36 ± 0.05 M. By fitting models to the spectrum of this
star around the Hγ line we find that it has an effective temperature Teff, A = 7500 ± 200 K
and a metallicity [Fe/H] = −0.3 ± 0.3. The mass of WASP 1628+10 B is only 0.135 ±
0.02 M. The effective temperature of this pre-He-WD is approximately 9200 K. The ULTRACAM
photometry of WASP 1628+10 shows variability at several frequencies around
40 cycles d−1, which is typical for δ Sct-type pulsations often observed in early A-type stars
like WASP 1628+10 A. We also observe frequencies near 114 and 129 cycles d−1, much
higher than the frequencies normally seen in δ Sct stars. Additional photometry through the
primary eclipse will be required to confirm that these higher frequencies are due to pulsations
in WASP 1628+10 B. If confirmed, this would be only the second known example of a
pre-He-WD showing high-frequency pulsations
Genome-wide association meta-analysis of corneal curvature identifies novel loci and shared genetic influences across axial length and refractive error.
Corneal curvature, a highly heritable trait, is a key clinical endophenotype for myopia - a major cause of visual impairment and blindness in the world. Here we present a trans-ethnic meta-analysis of corneal curvature GWAS in 44,042 individuals of Caucasian and Asian with replication in 88,218 UK Biobank data. We identified 47 loci (of which 26 are novel), with population-specific signals as well as shared signals across ethnicities. Some identified variants showed precise scaling in corneal curvature and eye elongation (i.e. axial length) to maintain eyes in emmetropia (i.e. HDAC11/FBLN2 rs2630445, RBP3 rs11204213); others exhibited association with myopia with little pleiotropic effects on eye elongation. Implicated genes are involved in extracellular matrix organization, developmental process for body and eye, connective tissue cartilage and glycosylation protein activities. Our study provides insights into population-specific novel genes for corneal curvature, and their pleiotropic effect in regulating eye size or conferring susceptibility to myopia
Multi-trait genome-wide association study identifies new loci associated with optic disc parameters
A new avenue of mining published genome-wide association studies includes the joint analysis of related traits. The power of this approach depends on the genetic correlation of traits, which reflects the number of pleiotropic loci, i.e. genetic loci influencing multiple traits. Here, we applied new meta-analyses of optic nerve head (ONH) related traits implicated in primary open-angle glaucoma (POAG); intraocular pressure and central corneal thickness using Haplotype reference consortium imputations. We performed a multi-trait analysis of ONH parameters cup area, disc area and vertical cup-disc ratio. We uncover new variants; rs11158547 in PPP1R36-PLEKHG3 and rs1028727 near SERPINE3 at genome-wide significance that replicate in independent Asian cohorts imputed to 1000 Genomes. At this point, validation of these variants in POAG cohorts is hampered by the high degree of heterogeneity. Our results show that multi-trait analysis is a valid approach to identify novel pleiotropic variants for ONH
Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017
A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4 (62.3 (55.1�70.8) million) to 6.4 (58.3 (47.6�70.7) million), but is predicted to remain above the World Health Organization�s Global Nutrition Target of <5 in over half of LMICs by 2025. Prevalence of overweight increased from 5.2 (30 (22.8�38.5) million) in 2000 to 6.0 (55.5 (44.8�67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic. © 2020, The Author(s)
Author Correction: Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017 (Nature Medicine, (2020), 26, 5, (750-759), 10.1038/s41591-020-0807-6)
An amendment to this paper has been published and can be accessed via a link at the top of the paper. © 2020, The Author(s)
Author Correction: Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017 (Nature Medicine, (2020), 26, 5, (750-759), 10.1038/s41591-020-0807-6)
An amendment to this paper has been published and can be accessed via a link at the top of the paper. © 2020, The Author(s)