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71.
This study aims to evaluate soil climate quantitatively under present and projected climatic conditions across Central Europe (12.1°–18.9° E and 46.8°–51.1° N) and the U.S. Central Plains (90°–104° W and 37°–49° N), with a special focus on soil temperature, hydric regime, drought risk and potential productivity (assessed as a period suitable for crop growth). The analysis was completed for the baselines (1961–1990 for Europe and 1985–2005 for the U.S.) and time horizons of 2025, 2050 and 2100 based on the outputs of three global circulation models using two levels of climate sensitivity. The results indicate that the soil climate (soil temperature and hydric soil regimes) will change dramatically in both regions, with significant consequences for soil genesis. However, the predicted changes of the pathways are very uncertain because of the range of future climate systems predicted by climate models. Nevertheless, our findings suggest that the risk of unfavourable dry years will increase, resulting in greater risk of soil erosion and lower productivity. The projected increase in the variability of dry and wet events combined with the uncertainty (particularly in the U.S.) poses a challenge for selecting the most appropriate adaptation strategies and for setting adequate policies. The results also suggest that the soil resources are likely be under increased pressure from changes in climate.  相似文献   
72.
Summary In order to obtain basic palaeomagnetic data on Upper Carboniferous, Permian and Triassic sediments collected from the NW Bulgaria, laboratory stability tests were extended from A.C. and thermal treatments to studies of mineral phase changes and to investigations of changes of magnetic anisotropy during laboratory procedures. Laboratory criteria were found which permitted to distinguish samples suitable for palaeomagnetic analyses from those representing rocks totally or almost totally chemically reworked during their history. Palaeomagnetic directions and pole positions derived from Stephanian, Lower Permian and Triassic rocks from the southern margin of the Moesian Platform are compatible with the values obtained for the tectonically stable North-European Platform.  相似文献   
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Summary Statistical evaluation of palaeomagnetic data from the Early Carboniferous to the Middle Triassic rocks in Europe, north of the Alpine tectonic belt, confirmed previously defined palaeotectonic stability of the whole European Plate since the Early Permian. The Trans-European Suture Zone represents a plate boundary, SW of which the Early Variscan and pre-Variscan formations show different degrees of palaeotectonic rotations, predominantly rotations of clockwise sense. A theoretical model simulating the translation and rotation movements was proposed showing that the West European Variscides underwent Hercynian palaeotectonic rotations comparable with the rotations derived for the Alpine tectonic belt.  相似文献   
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The joint article is concerned with derivation of equations of dynamics of the expansive nondecelerative universe and determination of its basic properties, relations, and parameters with the state equationp=–1/3.  相似文献   
76.
We present moderate-resolution (<5 Å) long-slit optical spectra of 51 nebular objects in the nearby Sculptor Group galaxy NGC 300 obtained with the 2.3 meter Advanced Technology Telescope at Siding Spring Observatory, Australia. Adopting the criterion of [S?ii]Total:Hα≥0.4 to confirm supernova remnants (SNRs) from optical spectra, we find that of 28 objects previously proposed as SNRs from optical observations, 22 meet this criterion with six showing [S?ii]Total:Hα of less than 0.4. Of 27 objects suggested as SNRs from radio data, four are associated with the 28 previously proposed SNRs. Of these four, three (included in the 22 above) meet the criterion. In all, 22 of the 51 nebular objects meet the [S ii]Total:Hα criterion as SNRs while the nature of the remaining 29 objects remains undetermined by these observations.  相似文献   
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Summary The Dinarides, the Eastern Alps and the Western Carpathians being situated at the borders of the Pannonian basin, are of very similar origin. Therefore, the results obtained in the investigation of correlations between Earth gravity field parameters (absolute geoid undulations, gravity anomalies), the surface topography and the shape of the Mohorovičić discontinuity, were compared. It was found that these three regions have the same basic characteristics, but also their own specific features. While the similarities follow clearly from these investigations, the found differences might partly be a consequence of non-uniformity and unmatched quality of data sets used for the three regions. A short version of this paper, entitled "Kindredness of three mountain belts at the border of the Pannonian basin — deduced from the behavior of the Mohorovičić discontinuity" was presented at the 7th International Symposium "Geodesy and Physics of the Earth", Potsdam, October 5–10, 1992 and published in the Proceedings. Presently a visiting professor at the Graz University of Technology, Institute for Theoretical Geodesy, Department for Physical Geodesy, Austria. Presently at the Berlin University of Technology, Germany, as an Alexander von Humboldt Foundation Research Fellow.  相似文献   
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