Composition and characteristics of particles in the ocean : evidence for present day resuspension

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 1980This study of particulate matter in the water column and the underlying surface sediments verifies the occurrence of local, present-day resuspension in the deep sea. The location of the major portion of this work was the South Iceland Rise, a region influenced by the flow of Norwegian Sea Overflow Water. Measured current velocities exceeded 20 cm/sec in the axis of the bottom current for the duration of the deployments, approximately two weeks. Particulate matter was sampled with Niskin bottles, to obtain the standing crop of suspended matter and with sediment traps, to obtain the material in flux through the water column. Box cores were taken to obtain surface sediment samples for comparison with the trap samples. Suspended particulate matter (SPM) and light-scattering studies demonstrate that in the Iceland Rise area the correlation of the L-DGO nephelometer to concentration of SPM differs between clear water and the nepheloid layer. Correlations of light scattering to SPM concentration also differ regionally, but for predicting concentration from light scattering, regression lines at two locations are indistinguishable. Particle size distributions have lower variance in the nepheloid layer than those in clear water which have roughly equal volumes of material in logarithmically increasing size grades from 1-20 μm. Apparent density differences between SPM in clear water and the nepheloid layer are not distinguishable in the Iceland Rise study; apparent densities increase in the nepheloid layer in the western North Atlantic. An apparent density of 1.1 g/cm3 adequately separates clear water from nepheloid layer samples in this region. Compositional variations seen between clear water and the nepheloid layer include a decrease in small coccoliths and an increase in clays and mineral matter. These compositional variations are more dramatic in the western North Atlantic region, due to dissolution of carbonate at the seafloor, later resuspended into the nepheloid layer. Sedimentological evidence of resuspension and redistribution of material are: 1) presence of sediment drifts throughout the Iceland Basin; 2) occurrence of coarse, glacial age sediments beneath the axis of the bottom current; and 3) differences in mineralogy, carbonate and organic carbon contents between surface sediments beneath the bottom current and those in a channel. A comparison of the vertical flux of material measured by sediment traps at 500 meters above bottom (mab) with the accumulation rate in cores, shows that the present-day surface input is an order of magnitude smaller than the accumulation rate. This observation suggests transport of material into some sections of the region by bottom currents or by turbidity currents. The horizontal flux of particulate matter into and out of the region by the bottom current is 100 kg/sec. This material may contribute to the formation of Gardar sediment drift downstream. The trends in % CaC03 and % organic carbon through the water column and in the surface sediments suggest that dissolution of carbonate and decomposition and consumption of organic carbon occurs primarily at the seafloor. These data also suggest preferential preservation at channel stations and/or preferential erosion beneath the bottom current. A comparison of sediment-trap samples with box-core surface samples further supports present-day resuspension. Benthic foraminifera, iron-oxidicoated planktonic foraminifera and the glacial, subpolar planktonic foraminifera (Neogloboquadrina pachyderma (sinistral)) in traps at 10,100 and a few specimens at 500 mab, provide conclusive evidence for local resuspension. The coarse fraction (>125 μm) of the sediment trap material collected at 10 mab comprises 21-34% of the samples Calculations indicate that this material is locally derived (few kilometers) resuspended material.This work was financially supported by the Woods Hole Oceanographic Institution, ONR through contracts N00014-79-C-00-7l NR 083-004, N00014-74-C0262 NR 083-004, and N00014-75-C-029l and ERDA through contracts 13-7923 and 13-2559

Benthic storms, nepheloid layers, and linkage with upper ocean dynamics in the western North Atlantic

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Geology 385 (2017): 304–327, doi:10.1016/j.margeo.2016.12.012.Benthic storms are episodic periods of strong abyssal currents and intense, benthic nepheloid (turbid) layer development. In order to interpret the driving forces that create and sustain these storms, we synthesize measurements of deep ocean currents, nephelometer-based particulate matter (PM) concentrations, and seafloor time-series photographs collected during several science programs that spanned two decades in the western North Atlantic. Benthic storms occurred in areas with high sea-surface eddy kinetic energy, and they most frequently occurred beneath the meandering Gulf Stream or its associated rings, which generate deep cyclones, anticyclones, and/or topographic waves; these create currents with sufficient bed-shear stress to erode and resuspend sediment, thus initiating or enhancing benthic storms. Occasionally, strong currents do not correspond with large increases in PM concentrations, suggesting that easily erodible sediment was previously swept away. Periods of moderate to low currents associated with high PM concentrations are also observed; these are interpreted as advection of PM delivered as storm tails from distal storm events. Outside of areas with high surface and deep eddy kinetic energy, benthic nepheloid layers are weak to non-existent, indicating that benthic storms are necessary to create and maintain strong nepheloid layers. Origins and intensities of benthic storms are best identified using a combination of time-series measurements of bottom currents, PM concentration, and bottom photographs, and these should be coupled with water-column and surface-circulation data to better interpret the specific relations between shallow and deep circulation patterns. Understanding the generation of benthic nepheloid layers is necessary in order to properly interpret PM distribution and its influence on global biogeochemistry.Funding for construction of the Bottom Ocean Monitor was provided by Lamont-Doherty Geological Observatory (now Lamont-Doherty Earth Observatory). BOM and mooring deployments and data analysis were funded by the Office of Naval Research (contracts N00014-75-C-0210 and N00014-80-C-0098 to Biscaye and Gardner at Lamont-Doherty; Contracts N00014-79-C-0071 and N00014-82-C-0019 at Woods Hole Oceanographic Institution and ONR Contracts N00014-75-C-0210 and N00014-80-C-0098 at Lamont-Doherty Geological Observatory to Tucholke), Sandia National Laboratories (contract SL-16-5279 to Gardner), the National Science Foundation (contract OCE 1536565 to Gardner and Richardson), Earl F. Cook Professorship (Gardner), and the Department of Energy (contract DE-FG02-87ER-60555 to Biscaye)

Development of a UK core dataset for geriatric medicine research: : a position statement and results from a Delphi consensus process

Funding AS and MW are funded by the Newcastle National Institute for Health (NIHR) Biomedical Research Centre, which also funded the initial meeting of academic clinicians in geriatric medicine during the Delphi process. The views expressed in this article are those of the authors and not necessarily those of the NIHR, the NHS, or the Department of Health. Acknowledgements The authors acknowledge the contributions of members of the UK Geriatric Medicine Core Dataset Extended Working Group.Peer reviewedPublisher PD

Fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin with gemtuzumab ozogamicin improves event-free survival in younger patients with newly diagnosed aml and overall survival in patients with npm1 and flt3 mutations

Purpose To determine the optimal induction chemotherapy regimen for younger adults with newly diagnosed AML without known adverse risk cytogenetics. Patients and Methods One thousand thirty-three patients were randomly assigned to intensified (fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin [FLAG-Ida]) or standard (daunorubicin and Ara-C [DA]) induction chemotherapy, with one or two doses of gemtuzumab ozogamicin (GO). The primary end point was overall survival (OS). Results There was no difference in remission rate after two courses between FLAG-Ida + GO and DA + GO (complete remission [CR] + CR with incomplete hematologic recovery 93% v 91%) or in day 60 mortality (4.3% v 4.6%). There was no difference in OS (66% v 63%; P = .41); however, the risk of relapse was lower with FLAG-Ida + GO (24% v 41%; P < .001) and 3-year event-free survival was higher (57% v 45%; P < .001). In patients with an NPM1 mutation (30%), 3-year OS was significantly higher with FLAG-Ida + GO (82% v 64%; P = .005). NPM1 measurable residual disease (MRD) clearance was also greater, with 88% versus 77% becoming MRD-negative in peripheral blood after cycle 2 (P = .02). Three-year OS was also higher in patients with a FLT3 mutation (64% v 54%; P = .047). Fewer transplants were performed in patients receiving FLAG-Ida + GO (238 v 278; P = .02). There was no difference in outcome according to the number of GO doses, although NPM1 MRD clearance was higher with two doses in the DA arm. Patients with core binding factor AML treated with DA and one dose of GO had a 3-year OS of 96% with no survival benefit from FLAG-Ida + GO. Conclusion Overall, FLAG-Ida + GO significantly reduced relapse without improving OS. However, exploratory analyses show that patients with NPM1 and FLT3 mutations had substantial improvements in OS. By contrast, in patients with core binding factor AML, outcomes were excellent with DA + GO with no FLAG-Ida benefit

Effect of remote ischaemic conditioning on clinical outcomes in patients with acute myocardial infarction (CONDI-2/ERIC-PPCI): a single-blind randomised controlled trial.

BACKGROUND: Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months. METHODS: We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed. FINDINGS: Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed. INTERPRETATION: Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI. FUNDING: British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden

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

Search for Bc+→π+μ+μ−B_c^+\to\pi^+\mu^+\mu^- decays and measurement of the branching fraction ratio B(Bc+→ψ(2S)π+)/B(Bc+→J/ψπ+){\cal B}(B_c^+\to\psi(2S)\pi^+)/{\cal B}(B_c^+\to J/\psi \pi^+)

International audienceThe first search for nonresonant $B_c^+\to\pi^+\mu^+\mu^-$ decays is reported. The analysis uses proton-proton collision data collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb$^{-1}$. No evidence for an excess of signal events over background is observed and an upper limit is set on the branching fraction ratio ${\cal B}(B_c^+\to\pi^+\mu^+\mu^-)/{\cal B}(B_c^+\to J/\psi \pi^+) < 2.1\times 10^{-4}$ at $90\%$ confidence level. Additionally, an updated measurement of the ratio of the $B_c^+\to\psi(2S)\pi^+$ and $B_c^+\to J/\psi \pi^+$ branching fractions is reported. The ratio ${\cal B}(B_c^+\to\psi(2S)\pi^+)/{\cal B}(B_c^+\to J/\psi \pi^+)$ is measured to be $0.254\pm 0.018 \pm 0.003 \pm 0.005$, where the first uncertainty is statistical, the second systematic, and the third is due to the uncertainties on the branching fractions of the leptonic $J/\psi$ and $\psi(2S)$ decays. This measurement is the most precise to date and is consistent with previous LHCb results