Tomographic observations of deep convection and the thermal evolution of the Greenland Sea Gyre, 1988-1989

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 February 1994The thermal evolution of the Greenland Sea Gyre is investigated using both historical data and tomographic results from the 1988-89 Greenland Sea Tomography Experiment. Thermal evolution of the gyre center divides naturally into three periods: a preconditioning phase (November-January), during which surface salinity is increased by brine rejection from ice formation and by entrainment but in which the mixed-layer deepens only slowly to a depth of some 150-200m, a deep mixing phase (February-March) during which the surface mixed-layer deepens rapidly to approximately 1500m in the gyre center purely under the influence of local surface cooling, and a restratification phase during which the products of deep mixing are replaced by inflowing Arctic Intermediate Water (AIW). The onset of the deep mixing phase occurs after ice formation in the gyre center stops, resulting in an area of open water where large heat fluxes can occur. In surrounding regions, including the odden region to the south, ice is still being formed, and the mixed layer does not deepen significantly. To the north and west, closer to the steep topography of the continental shelf, the inverse results show significant variability due to advection, and large temperature and heat content fluctuations with a period of about 50 days are seen. The effects of advection are deduced from heat and salt budgets, and appear to be important only during the restratification phase for intermediate depths, and only during the summer for the surface waters. Comparison of the tomographic results with point measurements indicates that deep mixing occurs in a field of small plumes in which dense water sinks downwards, surrounded by larger regions of upwelling. The plume geometry is consistent with that predicted by numerical and laboratory models. Dynamical processes for bringing the AIW to the surface in order to form deep water are not needed in this scenario, rather the surface waters are modified until they match the density of the AIW after which surface cooling drives convection

Tomographic observations of deep convection and the thermal evolution of the Greeland Sea Gyre, 1988-1989

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994.Includes bibliographical references (leaves 167-174).by Ryszard A. Pawlowicz.Ph.D

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Alirocumab and cardiovascular outcomes after acute coronary syndrome

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Alirocumab and Cardiovascular Outcomes after Acute Coronary Syndrome

BACKGROUN