Holocene history of the 79° N ice shelf reconstructed from epishelf lake and uplifted glaciomarine sediments

Acknowledgements This work was funded by a NERC standard grant (grant no. NE/N011228/1), and some radiocarbon analysis was funded by NEIF (grant NE/S011587/1; allocation number 2169.1118). We thank the Alfred Wegener Institute, particularly Angelika Humbert and Hicham Rafiq, for significant logistic support through the iGRIFF project. Additional support was provided by Station Nord (Jorgen Skafte), Nordlandair, Air Greenland, and the Joint Arctic Command. Naalakkersuisut (government of Greenland) provided scientific survey (VU-00121) and export (046/2017) licences for this work. Finally, we would like to thank our (Nanu Travel) field ranger Isak (and dog Ooni) for keeping us safe in the field and taking great pleasure in beating James A. Smith at cards. Financial support This research has been supported by the Natural Environment Research Council (grant no. NE/N011228/1).Peer reviewedPublisher PD

BedMachine v3: Complete Bed Topography and Ocean Bathymetry Mapping of Greenland From Multibeam Echo Sounding Combined With Mass Conservation

Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine-terminating glaciers. Here we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation approach. A new 150 m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface, yielding major improvements over previous data sets, particularly in the marine-terminating sectors of northwest and southeast Greenland. Our map reveals that the total sea level potential of the Greenland ice sheet is 7.42 ± 0.05 m, which is 7 cm greater than previous estimates. Furthermore, it explains recent calving front response of numerous outlet glaciers and reveals new pathways by which AW can access glaciers with marine-based basins, thereby highlighting sectors of Greenland that are most vulnerable to future oceanic forcing

Airborne radar sounding evidence for deformable sediments and outcropping bedrock beneath Thwaites Glacier, West Antarctica

The geologic and morphologic records of prior ice sheet configurations show evidence of rapid, back-stepping, meltwater intensive retreats. However, the potential for such a retreat in a contemporary glacier depends on the lithology of the current ice sheet bed, which lies beneath kilometers of ice, making its physical properties difficult to constrain. We use radar sounding and marine bathymetry data to compare the bed configuration of Thwaites Glacier to the bed of paleo-Pine Island Glacier. Using observed and modeled radar scattering, we show that the tributaries and upper trunk of Thwaites Glacier are underlain by ice flow-aligned bedforms consistent with deformable sediment and that the lower trunk is grounded on a region of high bed roughness consistent with outcropping bedrock. This is the same configuration as paleo-Pine Island Glacier during its retreat across the inner continental shelf

Cross-sectional study of the prevalence, causes and management of hospital-onset diarrhoea.

BACKGROUND:The National Health Service in England advises hospitals collect data on hospital-onset diarrhoea (HOD). Contemporaneous data on HOD are lacking. AIM:To investigate prevalence, aetiology and management of HOD on medical, surgical and elderly-care wards. METHODS:A cross-sectional study in a volunteer sample of UK hospitals, which collected data on one winter and one summer day in 2016. Patients admitted ≥72 hours were screened for HOD (definition: ≥2 episodes of Bristol Stool Type 5-7 the day before the study, with diarrhoea-onset >48 hours after admission). Data on HOD aetiology and management were collected prospectively. FINDINGS:Data were collected on 141 wards in 32 hospitals (16 acute, 16 teaching). Point-prevalence of HOD was 4.5% (230/5142 patients; 95% CI 3.9-5.0%). Teaching hospital HOD prevalence (5.9%, 95% CI 5.1-6.9%) was twice that of acute hospitals (2.8%, 95% CI 2.1-3.5%; odds ratio 2.2, 95% CI 1.7-3.0). At least one potential cause was identified in 222/230 patients (97%): 107 (47%) had a relevant underlying condition, 125 (54%) were taking antimicrobials, and 195 (85%) other medication known to cause diarrhoea. 9/75 tested patients were Clostridium difficile toxin positive (4%). 80 (35%) patients had a documented medical assessment of the diarrhoea. Documentation of HOD in medical notes correlated with testing for C. difficile (78% of those tested versus 38% not tested, p<0.001). 144 (63%) patients were not isolated following diarrhoea onset. CONCLUSION:HOD is a prevalent symptom affecting thousands of patients across the UK health system each day. Most patients have multiple potential causes of HOD, mainly iatrogenic, but only a third had medical assessment. Most were not tested for C. difficile and were not isolated