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Summary Research carried out on a favourable site in the Pre-Alps of Savoy has allowed the development of risk cartography where avalanche phenomena are defined according to three criteria: maximum extension, type of avalanche, and frequency of avalanche. The maps, composed of simple symbols, allowing easy updating, could be a useful tool for mountain professionals.With 4 Figures  相似文献   
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Satellite observations, fromEinstein,IUE, andIRAS, have been combined with ground-based observations to derive the quiescent energy distribution of the symbiotic star AG Draconis. A detailed comparison is made between the combined observations and various steady-state composite models, including blackbody accretion disks.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986.  相似文献   
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High-resolution spectra near 4 m of the four red giants— Peg,o 1 Ori, 10 Dra, and HR 1105—have been analysed to obtain estimates of the28Si/29Si and28Si/30Si abundance ratios. For Peg and the S star HR 1105, the28Si/29Si ratio is close to the solar ratio (28Si/29Si=20).29Si appears to be underabundant in the MS staro 1 Ori (28Si/29Si=40) and the M star 10 Dra (28Si/29Si53). The30Si isotope appears to be underabundant by, perhaps, about a factor of 2 in all four stars.  相似文献   
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From high-resolution spectra a non-local thermodynamic equilibrium analysis of the Mg  ii 4481.2-Å  feature is implemented for 52 early and medium local B stars on the main sequence (MS). The influence of the neighbouring line Al  iii 4479.9-Å  is considered. The magnesium abundance is determined; it is found that  log ɛ(Mg) = 7.67 ± 0.21  on average. It is shown that uncertainties in the microturbulent parameter Vt are the main source of errors in  log ɛ(Mg)  . When using 36 stars with the most reliable Vt values derived from O  ii and N  ii lines, we obtain the mean abundance  log ɛ(Mg) = 7.59 ± 0.15  . The latter value is precisely confirmed for several hot B stars from an analysis of the Mg  ii 7877-Å  weak line. The derived abundance  log ɛ(Mg) = 7.59 ± 0.15  is in excellent agreement with the solar magnesium abundance  log ɛ (Mg) = 7.55 ± 0.02  , as well as with the proto-Sun abundance  log ɛ ps (Mg) = 7.62 ± 0.02  . Thus, it is confirmed that the Sun and the B-type MS stars in our neighbourhood have the same metallicity.  相似文献   
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Natural Hazards - Human settlements in coastal areas are highly vulnerable to extreme events, especially in the Mediterranean area, which houses a large number of tourists during the summer and...  相似文献   
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The energy cycle characterizes basic aspects of the physical behaviour of the climate system. Terms in the energy cycle involve first and second order climate statistics (means, variances, covariances) and the intercomparison of energetic quantities offers physically motivated “second order” insight into model and system behaviour. The energy cycle components of 12 models participating in AMIP2 are calculated, intercompared and assessed against results based on NCEP and ERA reanalyses. In general, models simulate a modestly too vigorous energy cycle and the contributions to and reasons for this are investigated. The results suggest that excessive generation of zonal available potential energy is an important driver of the overactive energy cycle through “generation push” while excessive dissipation of eddy kinetic energy in models is implicated through “dissipation pull‘’. The study shows that “ensemble model” results are best or among the best in the comparison of energy cycle quantities with reanalysis-based values. Thus ensemble approaches are apparently “best” not only for the simulation of 1st order climate statistics as in Lambert and Boer (Clim Dyn 17:83–106, 2001) but also for the higher order climate quantities entering the energy cycle.  相似文献   
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