Study objective-The relation between a history of disorders suggestive of acute otitis media, symptoms, and findings of an examination of the tympanic membrane and doctors0 certainty of diagnosis. Also, to examine differences in prescribing habits for acute otitis media among doctors from different countries.Design-Questionnaires were completed by participating doctors for a maximum of 15 consecutive patients presenting with presumed acute otitis media.

At 25 "C and atmospheric pressure, the iodide-catalyzed decomposition of aqueous hydrogen peroxide in an undisturbed solution results in a maximum dissolved oxygen concentration of 0.12 M, or about 100 times the equilibrium solubility. At this concentration loss of gas occurs by homogeneous nucleation of bubbles. The supersaturation is readily destroyed by agitation or by sonication. As the external pressure is increased, the maximum attainable oxygen concentration increases linearly, reaching 0.18 M at 50 atm. In a plot of dissolved gas concentration versus external pressure, the supersaturation line is parallel to the Henry's law (saturation) line. The maximum supersaturation concentration at elevated pressure is independent of the nature of the pressurizing gas. While the pressure dependence of the supersaturation limit can be understood in terms of existing nucleation theory, the theory fails in attempts to calculate that limit quantitatively.

Limiting supersaturations for dissolved gases manifested by gas evolution oscillators and by direct experiments cannot be accounted for by the application of classical nucleation theory (CNT). The theory predicts bubbles containing 104-105 molecules at nucleation, with Helmholtz energies of ca. 104kT per bubble, much too high for homogeneous nucleation to occur spontaneously in a finite time. We investigate alternative unstable structures ('blobs') which do not have well-defined interfaces, which may exist transiently at {he point of nucleation as the precursors of true bubbles and which circumvent the need for a large Helmholtz energy for their formation. Effects due to global or local depletion of the solution concentration at nucleation are also considered.t This paper is Part 100 in the series Chemical Oscillations and

The rate constant for absorption of carbon dioxide into water increases as the stirring rate of the water is increased up to a maximum rate and then stays constant until the stirring is sufficiently vigorous to affect the surface area. At the maximum, the change in absorption rate with gas pressure shows excellent first-order kinetics and can be interpreted in terms of reversible exchange between the gas phase and a uniform solution, without invoking the existence of a surface layer of saturated solution. A general treatment is described for extracting the rate constant for absorption of gas from the kinetic data. By comparing the rate of absorption with the rate predicted by kinetic theory, we obtain an accommodation coefficient (γ) of (5.5 ± 0.5) × 10-8 at 20 °C. Absorption rates measured in solutions of sodium chloride decrease with increasing ionic strength. We note an approximately linear relationship between log γ and log s, where s is the gas solubility at 1 atm.

The method of flash photolysis has been used for direct measurement of the quantum yields of triplet formation in dilute chlorophyll solutions at 23 °C. In ether solution, the triplet yields were found to be 0⋅64 and 0⋅88 for chlorophyll a and b , respectively. In very dry hydro­carbon solution, the yields decrease by at least a factor of 5. It is suggested that the low yields of fluorescence and intersystem crossing in dry solvents are due to dissociation of excited singlet dimer chlorophyll into ground state monomer species.