Genome-wide association study identifies a variant in HDAC9 associated with large vessel ischemic stroke

Genetic factors have been implicated in stroke risk but few replicated associations have been reported. We conducted a genome-wide association study (GWAS) in ischemic stroke and its subtypes in 3,548 cases and 5,972 controls, all of European ancestry. Replication of potential signals was performed in 5,859 cases and 6,281 controls. We replicated reported associations between variants close to PITX2 and ZFHX3 with cardioembolic stroke, and a 9p21 locus with large vessel stroke. We identified a novel association for a SNP within the histone deacetylase 9(HDAC9) gene on chromosome 7p21.1 which was associated with large vessel stroke including additional replication in a further 735 cases and 28583 controls (rs11984041, combined P = 1.87×10−11, OR=1.42 (95% CI) 1.28-1.57). All four loci exhibit evidence for heterogeneity of effect across the stroke subtypes, with some, and possibly all, affecting risk for only one subtype. This suggests differing genetic architectures for different stroke subtypes

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb29

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The structure and growth of dykes and dyke-induced normal faults

This was a poster presented at EGU 2018: Dyke intrusion can accommodate extension during continental rifting through to seafloor spreading. To track dykes in active rifts, seismicity and ground deformation data is used to detect faults driven by dyke intrusion. It has particularly been recorded that graben-bounding normal faults develop above dykes that open as the host rock extends. Such dyke-induced normal faults have been observed along active continental rifts and oceanic spreading centres, as well as on volcanoes in various tectonic settings and on other planets. Because the location, structure, and displacement of dyke-induced normal faults reflect the volume, position, and dynamics of dykes, understanding how normal faults grow above and relate to dyke emplacement is fundamental to: (1) determining the role of dykes in continental break-up; (2) identifying dyke-induced faults and dykes along volcanic rifted margins, where they have yet to be observed, thus allowing their impact on ancient breakup events, margin evolution, and petroleum system development to be evaluated; (3) enabling extraction of more accurate dyke properties from monitored dyke-induced fault events, thereby improving eruption forecasting; and (4) deciphering the evolution of other planets. Over the last 40 years, numerous modelling approaches have been employed to assess how faults grow above dykes. Four hypotheses emanating from these models suggest faults either grow downwards from the surface, upwards from the dyke tip, a combination of both, or that they initiate between and grow towards the dyke tip and surface. Whereas final fault geometry is similar across these hypotheses, their growth patterns predict unique fault displacement trends. However, we cannot rigorously test these hypotheses due to a lack of sufficient 3D field exposures or geophysical images that detail dyke-induced fault structure. Furthermore, most models are 2D and only examine vertical fault growth, without considering how faults grow laterally, interact with each other, or respond to different dyke propagation directions and far-field stress conditions. The applicability of the different hypotheses to natural examples therefore remains contentious, compromising how we infer dyke properties from dyke-induced faults. We have identified a suite of dykes and dyke-induced faults, which extend for >100 km, in 3D seismic reflection data from offshore NW Australia. These data present a unique opportunity to quantify fault displacement patterns and thereby test hypotheses concerning fault growth above dykes. Associated with the dykes and dyke-induced faults are a series of pit chain craters, similar to structure observed in modern rifts and on other planetary bodies, allowing us to examine their 3D morphology. Overall, our work will provide new insights into the identification and growth of dykes and dyke-induced normal faults, revealing how they contribute to continental rifting and breakup

Unravelling intrusion-induced forced fold kinematics and ground deformation using 3D seismic reflection data

Sills emplaced at shallow-levels are commonly accommodated by overburden uplift, producing forced folds. We examine ancient forced folds developed above saucer-shaped sills using 3D seismic reflection data from the Canterbury Basin, offshore SE New Zealand. Seismic-stratigraphic relationships indicate sill emplacement occurred incrementally over ~31 Myr between the Oligocene (~35–32 Ma) and Early Pliocene (~5–4 Ma). Two folds display flat-topped geometries and amplitudes that decrease upwards, conforming to expected models of forced fold growth. Conversely, two folds display amplitudes that locally increase upwards, coincident with a transition from flat-topped to dome-shaped morphologies and an across-fold thickening of strata. We suggest these discrepancies between observed and expected forced fold geometry reflect uplift and subsidence cycles driven by sill inflation and deflation. Unravelling these forced fold kinematic histories shows complex intrusion geometries can produce relatively simple ground deformation patterns, with magma transgression corresponds to localisation of uplift

The reward and risk of social media for academics

We are three academics who are active on social media. We explore the motivations for and benefits of engaging with social media, as well as its costs and risks. Overall, we believe this engagement to be a net benefit for us, our employers and for wider society

Cenozoic contourites in the eastern Great Australian Bight, offshore southern Australia: implications for the onset of the Leeuwin Current

Thermohaline oceanic currents influence global heat transfer, controlling local and global variations in climate, biodiversity, and the terrestrial biosphere. Paleoceanographic studies typically use biostratigraphic and geochemical proxies to reconstruct the dynamics of these currents in Earth’s ancient oceans, although seismic reflection data have also been successfully employed, most commonly in the North Atlantic Ocean. Here we use 2D seismic reflection data from the Ceduna Sub-basin, Great Australian Bight, offshore southern Australia to describe middle Eocene-to-Recent contourites deposited within an overall carbonate-dominated succession. These deposits comprise large (100 m wavelength by up to 50 m tall) bedforms and deep (10–90 m), wide (up to 3 km) erosional scours. The scours are particularly well-developed at one specific stratigraphic level, defining moats that encircle Middle Eocene shield volcanoes, which formed syn-depositional bathymetric highs. We suggest that sediment erosion, transport, and deposition record middle Eocene initiation of the Leeuwin Current, one of the most important ocean currents in the southern hemisphere. Deepest seabed scouring occurs within the middle of the middle Eocene-to-Recent sequence, and may reflect middle Miocene waxing of the so-called ‘proto-Leeuwin Current’, possibly driven by changes in ocean circulation patterns caused by the Miocene Global Optimum. The results of this seismic reflection-based study are consistent with results derived from other paleoceanographic proxies, thereby highlighting the continued key role seismic reflection data have in understanding the occurrence, geographical distribution, and significance of ancient ocean currents