Internet browsers use security protocols to protect sensitive messages. An inductive analysis of TLS (a descendant of SSL 3.0) has been performed using the theorem prover Isabelle. Proofs are based on higher-order logic and make no assumptions concerning beliefs or finiteness. All the obvious security goals can be proved; session resumption appears to be secure even if old session keys have been compromised. The proofs suggest minor changes to simplify the analysis.TLS, even at an abstract level, is much more complicated than most protocols that researchers have verified. Session keys are negotiated rather than distributed, and the protocol has many optional parts. Nevertheless, the resources needed to verify TLS are modest: six man-weeks of effort and three minutes of processor time.

Ammonia excretion by brook trout (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri) was measured in relation to nitrogen consumption, body weight (15–154 g for rainbow trout and 50–360 g for brook trout), and temperature (11.2–21.0 °C) under laboratory conditions. Four natural diets, collected from Castle Lake, California, and a commercial pellet diet were fed to the trout in gelatin capsules at feeding rates from 2.5 to 5% body weight∙d−1. Nitrogen consumption was the most important factor influencing ammonia excretion, followed by body weight and temperature. Testing the models with an independent data set revealed good agreement between measured and predicted rates of excretion. The models seem to estimate adequately ammonia excretion by trout in both natural and artificial aquatic systems.Key words: models, ammonia excretion, nitrogen consumption, body weight, temperature, multiple regression, rainbow trout, brook trout

Big Soda Lake has shifted from a partially closed to an open meromictic system, probably due to a progressive depression of the chemocline to a level below that of subsurface inflow. The stability increase initially accompanying that shift has been followed by a gradual decrease in stability. The observed mean annual work done and chemocline descent rate indicate that meromixis in Big Soda Lake is unlikely to persist for longer than another few decades.

SynopsisSpawning of razorback suckers, Xyrauchen texanus, in Lake Mohave occurred from 10-22°C and larvae were collected at water temperatures from 10-15" C in 1982 and 1983. In the laboratory, hatching success was similar from 12-20°C, but reduced hatching success was found at 10°C while none hatched at, 8" C. Development rate and oxygen consumption were positively related to incubation temperature. Direct effects of ambient Lake Mohave water temperatures on hatching success of razorback sucker embryos are considered minimal. Historical spawning temperatures for the species are hypothesized based upon successful incubation temperatures and comparison to the white sucker, Catostomus commersoni.

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