John Marshall

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Satellite altimetric observations of the ocean reveal surface pressure patterns in the core of the Antarctic Circumpolar Current (ACC) that propagate downstream (eastward) but slower than the mean surface current by about 25%. The authors argue that these observations are suggestive of baroclinically unstable waves that have a steering level at a depth of(More)
BACKGROUND & AIMS Postinfectious irritable bowel syndrome (PI-IBS) is a common clinical phenomenon. To better define its incidence and epidemiology, a large cohort study was initiated after the contamination of a municipal water supply led to a large outbreak of acute Escherichia coli 0157:H7 and Campylobacter jejuni gastroenteritis. METHODS Local(More)
An observational, modeling, and theoretical study of the scales, growth rates, and spectral fluxes of baro-clinic instability in the ocean is presented, permitting a discussion of the relation between the local instability scale; the first baroclinic deformation scale R def ; and the equilibrated, observed eddy scale. The geography of the large-scale,(More)
BACKGROUND The management of patients with acute nonvariceal upper gastrointestinal bleeding has evolved substantially over the past 10 years amid a paucity of published consensus guidelines. PURPOSE To provide evidence-based management recommendations that address clinically relevant issues. REVIEW AND CONSENSUS PROCESSES: A multidisciplinary consensus(More)
[1] The interpretation of surface altimetric signals in terms of Rossby waves is revisited. Rather than make the long-wave approximation, the horizontal scale of the waves is adjusted to optimally fit the phase speed predicted by linear theory to that observed by altimetry, assuming a first baroclinic mode vertical structure. It is found that in the(More)
We present a physical, laboratory-scale analog of large-scale atmospheric circulation and develop an observatory for it. By combining observations of a hydro-dynamically unstable flow with a 3D numerical fluid model, we obtain a real-time estimate of the state of the evolving fluid which is better than either model or observations alone. To the best of our(More)
Within basins that exhibit open-ocean convection, convectively mixed fluid is often observed in regions of upward-doming isopycnal surfaces, preconditioned by either cyclonic circulation and/or bottom topography. Here, an equilibrium statistical theory for open-ocean convection, developed in the context of two-layer heton models, is adapted to study the(More)
BACKGROUND A discrete choice experiment (DCE) is a preference survey which asks participants to make a choice among product portfolios comparing the key product characteristics by performing several choice tasks. Analyzing DCE data needs to account for within-participant correlation because choices from the same participant are likely to be similar. In this(More)
Evidence of enhanced oceanic convection over Maud Rise in the Weddell Sea indicates that bottom topography may play a role in selecting the location and scale of deep convecting oceanic chimneys below large scale atmospheric negative buoyancy forcing. Topographic preconditioning of open ocean deep convection is studied using an ide-alized,(More)