North Atlantic Deep Water Production during the Last Glacial Maximum.

Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present neodymium isotope measurements from cores throughout the Atlantic that reveal glacial-interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ(13)C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters.Sample material was provided by the Godwin Laboratory for Paleoclimate Research at the University of Cambridge, the International Ocean Discovery Program, the GeoB Core Repository at the MARUM – Center for Marine Environmental Sciences, University of Bremen and Petrobras. Jo Kerr and Aurora Elmore are thanked for providing additional samples. The data reported in this paper are listed in supplementary information and archived in Pangaea (www.pangaea.de). Thiago Pereira dos Santos is thanked for providing the unpublished age model data for GL1090; Jo Clegg and Vicky Rennie are thanked for technical support and Natalie Roberts for helpful discussions. Radiocarbon analyses were supported by NERC radiocarbon grant 1752.1013 and Nd isotope analyses by NERC grant NERC NE/K005235/1 and NERC NE/F006047/1 to AMP. JNWH was supported by a Rutherford Memorial Scholarship. SM was funded through the DFG Research Center/Cluster of Excellence “The Ocean in the Earth System”. CMC acknowledges financial support from FAPESP (Grant 2012/17517-3).This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Nature Publishing Group

Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report

The authors wish to thank the CSIRO Marine National Facility (MNF) for its support in the form of sea time on RV Investigator, support personnel, scientific equipment and data management. All data and samples acquired on the voyage are made publicly available in accordance with MNF Policy. All raw and processed data acquired by MNF equipment on MNF voyages will be archived by MNF data support staff in the enduring CSIRO Data Access Portal, https://data.csiro.au. Metadata records will be made publicly available at http://www.marlin.csiro.au. Processed data and data products will be made publicly available through Data Trawler http://www.cmar.csiro.au/data/trawler/index.cfm, the MNF web data access tool http://www.cmar.csiro.au/data/underway/, and/or from national or world data centres most suitable for the dissemination of particular data types.Other Australian Program Support Smaller projects have attracted funding to support research activities post-cruise these include the following: 1. Australian and New Zealand IODP Committee (ANZIC) Special Analytical Support Grant. Project Title: Using ancient phytoplankton communities and genes to illuminate future ocean responses. Researchers involved: L. Armand, L. Armbrecht, M. Ostrowski, & S. George. 2. Australian Antarctic Division Australian Antarctic Science Grant (#4320). Project Title: Characterising East Antarctic seabed habitats. Researchers involved: Post, A.L., & Smith, J. 3. Australian Antarctic Division Australian Antarctic Science Grant (#4419). Project Title: Response of the Totten Glacier to past climate warming. Researchers involved: Noble, T., Armand, L., Chase, Z., & Halpin, J.The Sabrina Sea Floor Survey was a major marine geoscience expedition to the Antarctic margin which took place between 14 January and 7 March 2017. It sailed on the Australian Marine National Facility vessel RV Investigator. This document describes survey activities, data collected on the ship and important metadata. Some preliminary results are included and the location of samples and data sets reported for future use. The report also provides information on data ownership and acknowledgement for future use and publication. It is intended as an aid to future research and use of results and has not been rigorously edited and peer-reviewed.Australian Research Council (DP170100557), Australian Antarctic Science Grant Program (AAS #4333), Italian Antarctic program support PNRA TYTAN Project (PdR 14_00119), Spanish Ministry of Economy and Competitivity (MINECO) (CTM2015-60451-C2-1-P & CTM2015-60451-C2-2-P), United States National Science Foundation's Polar Program - Antarctic Integrated System Science. #1143834, 1143836, 1143837, 1143843, 1313826

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Concentrations and isotopic ratios of thorium and uranium in pelagic sediments

The predictable in situ production of 230Th from the decay of uranium in seawater, and its subsequent removal by scavenging onto falling particles, provides a valuable tool for normalizing fluxes to the seafloor. We describe a new application, determination of the 232Th that dissolves in the water column and is removed to the seafloor. 232Th is supplied to the ocean in continental minerals, dissolution of which leads to a measurable standing stock in the water column. Sedimentary adsorbed 232Th/230Th ratios have the potential to provide a proxy for estimating the amount of dissolved material that enters the ocean, both today and in the past. Ten core top samples were treated with up to eight different leaching techniques in order to determine the best method for the separating adsorbed from lattice bound thorium. In addition, separate components of the sediments were analyzed to test whether clay dissolution was an important contribution to the final measurement. There was no systematic correlation between the strength of acid used in the leach and the measured 232Th/230Th ratios. In all cases clean foraminifera produced the same ratio as leaches on bulk sediment. In three out of five samples leaches performed on non-carbonate detritus in the <63 µm size fraction were also identical. Without additional water column data it is not yet clear whether there is a simple one to one correlation between the expected deep-water 232Th/230Th and that produced by leaching, especially in carbonate-rich sediments. However, higher ratios, and associated high 232Th adsorbed fluxes, were observed in areas with high expected detrital inputs. The adsorbed fraction was ~35-50% of the total 232Th in seven out of ten samples. Our 230Th normalized 232Th fluxes are reasonable by comparison to global estimates of detrital inputs to the ocean. In nine cases out of ten, the total 230Th-normalized 232Th flux is greater than predicted from the annual dust fall at each specific location, but lower than the average global detrital input from all sources