An overview of the petrography and petrology of particles from aggregate sample from asteroid Bennu

The OSIRIS‐REx mission returned a sample of regolith from the carbonaceous asteroid Bennu in September 2023. We present preliminary in situ investigations of the petrology and petrography of selected particles ranging in size from 0.5 to 3 mm. Using a combination of optical and electron beam techniques, we investigate whole specimens and polished sections belonging to morphologically and visually distinct categories of particles. We find that morphological differences in the particles are reflective of petrographic and petrologic differences, leading to the conclusion that we have at least two distinct major lithologies in the bulk sample. Our findings support predictions from remote sensing, suggesting that the morphological differences observed in the boulder population of Bennu correspond to petrologic differences. Our data provide insight into the geologic activity on Bennu's parent body and the petrographic framework needed to contextualize the detailed analyses of this pristine asteroidal material

Virtual reality experience in haemato-oncology patients—technical evaluation (ViREB-TE)

Abstract Purpose Virtual reality (VR) is increasingly being used in health care. However, its use as part of therapy during prolonged inpatient treatments is less well established. This study assessed the experience of hemato-oncology inpatients, their caregivers or relatives and staff of a 20-min VR expedition to assess acceptability, safety, and opportunities to improve inpatient experience. Methods Through several familiarisation days, participants took part in a supervised 20-min trial of a 3-dimensional (3-D) VR escape using Google Wander™ delivered via an Oculus Quest 2 VR Headset™. Participants completed a validated survey of their VR experiences. Results Thirty-one patients, 10 staff members and 9 relatives or patient friends visited 55 unique countries, with 19 participants (38%) wishing to visit home, family, or friends. All participants enjoyed the experience, felt energised or had a sense of well-being following the immersion. One participant felt fatigued by the experience. No one found the experience disagreeable nor had difficulty in navigating within the device. No participant complained of nausea, with two patients experiencing dizziness and one developing a headache. Nine participants (18%) complained of eyestrain, while 12 participants (24%) complained of a sense of “head fullness”. None of the symptoms were perceived to need to shorten the immersion experience nor lasted beyond the immersion. Conclusion 3D-VR “holiday from hospital” can be used safely in acute inpatients with little supervised training. The broad acceptance of the technology, potentially providing a distraction from clinical care routines

Bidirectional bedform fields at the head of a submarine canyon (NE Atlantic)

Submarine canyons are known to force ocean mesoscale circulation and local hydrodynamics. Alternate up- and down-canyon near-bottom flows have been widely documented along the upper reaches, connecting the canyon heads with the contiguous outer shelves and vice versa. Nonetheless, we still miss clear evidence of bedform fields expressing these complex patterns. In this study, through a multi-scale analysis in both space and time, we document rare asymmetric bedforms, up to 880 m long and 10 m high, developing within a depth range of 168-220 m at the head of the Whittard Canyon (NE Atlantic). One field of well-developed sandwaves has an atypical up-slope asymmetry, with the steeper slope facing the shallower regions of the shelf, and contrasting with surrounding down-slope sandwaves facing the canyon. The bedforms are interpreted to represent both up-slope and down-slope bottom currents connecting the upper reaches of the canyon to the outer shelf on the southern Celtic Margin, in the Bay of Biscay. The sandwaves were surveyed with shipboard Multibeam bathymetry (5 m grid cell resolution), AUV sidescan sonar (0.15 m grid cell resolution) and ROV footage, and sampled with three ROV-mounted vibro-cores and two box-cores. Sidescan sonar mosaics groundtruthed by sediment samples and ROV footage show with unprecedented detail spectacular trains of fresh overprinting megaripples, previously undocumented sand peaks and bowl-shaped depressions on the crests of the tallest sandwaves. Differences in sedimentary settings and benthic habitats indicate that these features are currently active in particularly dynamic areas, allowing for very slow migration of sandwaves. Numerical modelling together with concurrent hydrographic observations suggest large-amplitude semi-diurnal internal tides, possibly transitioning to asymmetric internal bores, as the main mechanism maintaining the mapped up-slope sandwaves. This work highlights the importance of uncommon sediment dynamics in canyon head environments and adds insight to the traditional notions of gravity-driven processes, being dominant in these environments, envisaging implications for improving geo-hazard assessment of mobile substrates and quantification of offshore sediment and carbon fluxes