A jet airliner with 54 persons aboard was delayed on the ground for three hours because of engine failure during a takeoff attempt. Most passengers stayed on the airplane during the delay. Within 72 hours, 72 per cent of the passengers became ill with symptoms of cough, fever, fatigue, headache, sore throat and myalgia. One passenger, the apparent index case, was ill on the airplane, and the clinical attack rate among the others varied with the amount of time spent aboard. Virus antigenically similar to A/Texas/1/77(H3N2) was isolated from 8 of 31 passengers cultured, and 20 of 22 ill persons tested had serologic evidence of infection with this virus. The airplane ventilation system was inoperative during the delay and this may account for the high attack rate.

We have developed a new Monte Carlo code called ATMOCOSMICS based on GEANT 4 that simulates the interaction of cosmic rays with the Earth's atmosphere. The code allows to compute the flux of secondaries (e-, e+, protons, neutrons, gammas, muons, pions, …) at user-defined atmospheric depths and/or altitudes. Profiles of the energy deposited by atmospheric shower particles into the atmosphere vs depth and/or altitude can be calculated. We present examples of simulation results obtained with the code, and compare them with experimental data.

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Abstract.A total of more than 140 000 kg of smallmagnitude rockfall deposits was measured in eight rockfall collectors of altogether 940 m 2 in size between 1999-2003 below a 400-600 m high rock face in the Reintal, German Alps. Measurements were conducted with a temporal resolution up to single days to attribute rockfall intensity to observed triggering events. Precipitation was assessed by a rain gauge and high-resolution precipitation radar. Intense rainstorms triggered previously unreported rockfall intensities of up to 300 000 g/(m 2 h) that we term "secondary rockfall event." In comparison to dry periods without frost (10 −2 g/(m 2 h)), rockfall deposition increased by 2-218 times during wet freeze-thaw cycles and by 56-thousand to 40-million times during secondary rockfall events. We obtained three nonlinear logistic growth models that relate rockfall intensity [g/(m 2 h)] to rainfall intensity [mm/h]. The models account for different rock wall intermediate storage volumes, triggering thresholds and storage depletion. They apply to all rockfall collector positions with correlations from R 2 =0.89 to 0.99. Thus, the timing of more than 90% of the encountered rockfall is explained by the triggering factor rainfall intensity. A combination of rockfall response models with radar-supported storm cell forecast could be used to anticipate hazardous rockfall events, and help to reduce the exposure of individuals and mobile structures (e.g. cable cars) to the hazard. According to meteorological recordings, the frequency of these intense rockfall events is likely to increase in response to global warming.

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