Biomedical subjects
Publications and source records attributed to D Cordoba.
We give conditions that rule out formation of sharp fronts for certain two-dimensional incompressible flows. We show that a necessary condition of having a sharp front is that the flow has to have uncontrolled velocity growth. In the case of the quasi-geostrophic equation and two-dimensional Euler equation, we obtain estimates on the formation of semi-uniform fronts.
We study ideal incompressible magnetohydrodynamics in two dimensions. We obtain an exponential estimate on the closing of the angle at hyperbolic saddle points of the magnetic stream function under the assumption that the velocity remains bounded. The analytic results are supported by numerical simulations. These results give evidence against a standard scenario for singularity formation for these equations.
We study solutions of the two-dimensional quasi-geostrophic thermal active scalar equation involving simple hyperbolic saddles. There is a naturally associated notion of simple hyperbolic saddle breakdown. It is proved that such breakdown cannot occur in finite time. At large time, these solutions may grow at most at a quadruple-exponential rate. Analogous results hold for the incompressible three-dimensional Euler equation.
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We injected technical quality DDVP ip into 13 dogs at a dose of 30 mg/kg, a dose 100% lethal in 27 minutes. We monitored blood pH, arterial gases, and cholinesterase activity before and during the intoxication and found acidosis. We used iv sodium bicarbonate and achieved recovery of acid-base balance, improvement in the poisoned state, and survival of 84.6% of the patients.
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