美国城市旅游

美国城市旅游对我国发展都市旅游有借鉴意义。本介绍了美国在散客旅游方式、旅游交通、城市旅游资源开发、旅游宣传资料以及旅馆业经营方式方面的一些做法。     

The maintenance of the night-time ionosphere at mid-latitudes. II. The ionosphere above St. Santin

The total rate of recombination in the night-time ionosphere above St. Santin (at L = 1.8) was estimated using a model atmosphere and the results were compared with the observed rate of change of total electron content to determine the net influx of plasma. Horizontal transport under the influence of electric fields was measured but at the latitude of St. Santin this was always small and averaged over the night as a whole the contribution was negligible. Downward diffusion provided the main source of plasma and the flux predicted was compared with the flux measured at 450 km. The comparison was good provided the model atmosphere was modified to use exospheric temperatures based on actual measurements by the incoherent scatter radar. A comparison with the results obtained at Malvern (Paper I) confirmed that the saturation time for the protonosphere at L = 1.8 is far less than at L = 2.6 and that the downward flux from the saturated protonosphere was also less.     

北美自由贸易协定与美墨关系

北美自由贸易协定(NAFTA)的签定是冷战结束后美墨关系发生变化的一个重要标志,是经济全球化过程中的重要发展趋势。美、加、墨通过建立经济合作关系,实行经济自由化、一体化,既有利于三国经济的互利合作,又促进墨西哥的政治经济体制改革,为墨西哥对外经济开放、发展外向型经济提供机遇。但美墨之间由于历史遗留问题以及墨西哥国内依然存在的强烈民族主义倾向,墨西哥经济对美国经济的过分依赖等,使美墨关系还存在不确定的变数。由于墨西哥积极发展与亚太地区和欧盟的经济合作关系,未来美墨关系的发展,以及建立北美自由贸易区统一货币等问题,是对NAFTA的一个严峻考验。     

The maintenance of the night-time ionosphere at mid-latitudes. I. The ionosphere above Malvern

The total rate of recombination in the night-time ionosphere above Malvern (at L = 2.6) was estimated using a model atmosphere, and the results were compared with the observed rate of change of total electron content to determine the net influx of plasma. Horizontal transport under the influence of electric fields was an important factor on a time-scale of an hour or less but when averaged throughout the night made little contribution. The main influx of plasma was a downward diffusion from the protonosphere, especially before midnight. The average downward flux increased steadily as the protonosphere filled after a magnetic storm, with a saturation time of at least 8 days.     

The Paganism of the Ancient Prussians.

Some contemporary fairytales have antecedents in pre-modern documents. That oral traditions lie behind much medieval literature is likely; this is no less true for the “Constance” tales (ATU 706 and ATU 706C). Through the historic–geographic method, Alexander H. Krappe determined that these plots originated in Eastern Europe. An ahistorical anecdote in The Chronicle of Morea is related to the earliest documented variants of the “Constance” group, two thirteenth-century romances, Mai und Beaflor and Le Roman de la Manekine, and two episodes in historical narratives by Matthew Paris and Jans der Enikel. In addition to the basic outline of events, the common themes of relationship between an imperial centre and outlying districts are shared. The birth of this plot type, under the influence of both western and eastern sources, may then be situated in the historical context of the Fourth Crusade's aftermath in formerly Byzantine territory.