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821.
In the following paper we argue that each wind-driving star in relative motion with respect to the ambient interstellar medium experiences a force exerted on its central wind-generating body. The exact magnitude of this force depends on the actual geometry of the counterflow configuration of stellar and interstellar winds for a particular kinematic situation which is especially sensitive to whether the interstellar flow is subsonic or supersonic. It will, however, be demonstrated here that this force is of an accelerating nature, i.e., it operates like a rocket-motor, as long as the peculiar motion of the wind-driving star with respect to the ambient interstellar medium remains subsonic.Here we use a specific analytical model to describe theoretically the specific counterflow configuration for the case of the solar system in a subsonic peculiar motion with respect to the local interstellar medium assuming irrotational and incompressible flows. We can work out a quantitative number for the accelerating force governing the Sun's motion at present. The net reaction force exerted on the solar body is then mediated by the asymmetric boundary conditions to which the distant solar wind field has to adapt.Next we study the indirect action of such a force on orbiting Keplerian objects like planets, planetesimals and comets. Since this force only influences the central solar body, but not the planets themselves, the problem is different from the treatment of a constant perturbation force perturbing the Keplerian orbits. We present a perturbation analysis treating the action of a corresponding position-dependent perturbation force resulting in secular changes of the orbital elements of Keplerian objects. It is found that changes are accumulating more rapidly in time the closer to the sun the orbiting bodies are. Main axis and perihelion distances are systematically increasing. Especially pronounced are changes in the perihelion position angle of the objects. For solar wind mass losses larger than the Sun's present value by a factor of 1000 (T-Tauri phase of the Sun,) the migration periods calculated for the planet Mercury are of the same order of magnitude as that for corresponding general relativistic migration.  相似文献   
822.
The predominant 1480 Ma granites and rhyolites of the St. Francois Mountains, southeastern Missouri, are intruded by mafic rocks. A 40Ar—39Ar study of some of these, the Skrainka Mafic Group, indicates an age of ~ 1240 Ma, significantly younger than the host rocks, significantly older than Grenville/Keweenawan age, and close to the age of similar rocks in Labrador.  相似文献   
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Between 1 January 1980 and 28 July 1981, a series of large earthquakes with body-wave magnitudes around 7, took place along the western segment of the Alpide belt. The sequence started in the Azores and migrated eastward along the belt at a rate of about 4400 km/yr with consecutive large events in northern Algeria, southern Italy, southern Greece and Iran. Two different methods are employed to identify similar series and corresponding migration velocities during earlier time periods of this century. The data set used contains all earthquakes with body-wave magnitudes larger than 6.3 and covers the time interval 1901–81. The concept of linear migration is tested for eastward and/or westward propagation, considering high migration velocities from 1600 to 11 000 km/yr. Results obtained are not homogeneous with respect to the two opposite migration directions, west-east and east-west, and we interpret this as a net drift of earthquake activity from the west to the east. Our efforts here are concentrated on analysis of observational data and on estabilishing the uniqueness of migration patterns. Because of the complexity of the tectonic system in question, we did not attempt to establish a mechanism explaining the migration of the observed earthquake sequences.  相似文献   
827.
In the Mediterranean area modern economic development is concentrating more and more on the favourably situated coastal plains. The coastal plains of Calabria, which are examined on the basis of land utilization mapping, form, in this backward S Italian region, individually characteristic areas of different levels of agrarian development. Areas with insufficient aid and stagnating development and those with a strong initial developmental impulse and hesitant further development, stand face-to-face with areas with a continuous upward trend. The latter fit into the ranks of those consolidated agricultural regions of S Italy in which government aid and private initiative are multifariously intertwined and together support the process of development. Up to now, however, the different non-agricultural interests have impeded the continuing progress of the process more and more and given rise to awkward land utilization conflicts. Through settlement expansion, the building of transport facilities and ports for industrial zones as well as tourism, the use of land for agriculture is, to an increasing extent, being taken away so that regional planning seems imperative.  相似文献   
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Summary Vertical temperature traces in the north-western Mediteranean show remarkably leafy structures at depths between 100 m and 300 m. The individual layers are stable over several days. Their horizontal extension is larger than 20 nm. The thickness amounts to 25–50 m. It is suggested that these interleavings of slightly different water masses are due to lateral mixing processes in the vicinity of the working area.
Inversionen unterhalb der Sprungschicht im nordwestlichen Mittelmeer
Zusammenfassung Temperaturprofile im nordwestlichen Mittelmeer weisen eine auffällig blättrige Struktur in Tiefen von 100–300 m auf. Die einzelnen Schichten sind über mehrere TAge stabil. Ihre horizontale Ausdehnung ist größer als 20 sm. Die vertikale Mächtigkeit beträgt 25–50 m. Es wird angenommen, daß die schichtförmigen Einschübe schwach unterschiedlicher Wassermassen durch Vermischung in der Umgebung des Arbeitsgebietes entstanden sind.

Inversions du gradient de température au-dessous de la thermocline dans le Nord Ouest de la Méditerranée
Résumé Les tracés verticaux de la température, dans le Nord Ouest de la Méditerranée ont des structures remarquablement superposées en minces feuillets, à des profondeurs comprises entre 100 et 300 mètres. Les couches individuelles sont stables pendant plusieurs jours. Elles s'étendent horizontalement sur plus de 20 milles nautiques. Leur épaisseur atteint 25 à 50 mètres. On suppose que ces superpositions de masses d'eau légèrement différentes sont dues à des processus de mélange latéral au voisinage de la région d'opération.
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