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671.
Labour shortage was an integral feature of the communist system of economic management and one that seemed most unlikely to
persist in the face of systemic transformation. A casual examination of the unemployment rates that have emerged throughout
most of Central and Eastern Europe (CEE) during the course of the past decade might suggest that this early assumption was
correct. However, within the region the aggregate rate of joblessness, as well as the behaviour of national output, mask the
fact that certain, major urban centres appear to have weathered well the storms caused by exposure to western markets and
stringent fiscal and monetary policies. In these centres transformation has meant, to a greater or lesser degree, industrial
modernisation and this begs the question of whether the human capital portfolios of the inherited labour force match up to
the requirements of the new environment. This paper examines the meaning of the concept of labour shortage and presents the
findings from a survey of employers in four leading cities of three major CEE economies designed to elicit if, and how, manpower
requirements are being met in the present climate. The results indicate that, somewhat paradoxically, labour shortage persists
in the more flexible markets of the post-communist era and that firms do not expect the situation to change radically in the
near future.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
672.
R. Meerkötter U. Schumann D. R. Doelling P. Minnis T. Nakajima Y. Tsushima 《Annales Geophysicae》1999,17(8):1080-1094
A parametric study of the instantaneous radiative impact of contrails is presented using three different radiative transfer models for a series of model atmospheres and cloud parameters. Contrails are treated as geometrically and optically thin plane parallel homogeneous cirrus layers in a static atmosphere. The ice water content is varied as a function of ambient temperature. The model atmospheres include tropical, mid-latitude, and subarctic summer and winter atmospheres. Optically thin contrails cause a positive net forcing at top of the atmosphere. At the surface the radiative forcing is negative during daytime. The forcing increases with the optical depth and the amount of contrail cover. At the top of the atmosphere, a mean contrail cover of 0.1% with average optical depth of 0.2 to 0.5 causes about 0.01 to 0.03 Wm−2 daily mean instantaneous radiative forcing. Contrails cool the surface during the day and heat the surface during the night, and hence reduce the daily temperature amplitude. The net effect depends strongly on the daily variation of contrail cloud cover. The indirect radiative forcing due to particle changes in natural cirrus clouds may be of the same magnitude as the direct one due to additional cover. 相似文献
673.
High-resolution seismic studies of gas hydrates west of Svalbard 总被引:2,自引:0,他引:2
A strong bottom-simulating reflection (BSR) with high-amplitude variations is detectable in high- resolution reflection seismic
profiles west of Svalbard. Above the BSR, anomalously high velocities up to 1840 m/s, calculated from high-frequency ocean-bottom
hydrophone (HF-OBH) data, indicate the existence of gas-hydrated sediments. Below the BSR, a low-velocity layer, interpreted
as gas-bearing sediments, shows thickness variations from 12 to 25 m. In addition, two other low-velocity layers clearly containing
free gas are detected within the classic hydrate stability zone (HSZ) where, a theoretical viewpoint, free gas cannot exist.
Received: 6 August 1997 / Revision received: 26 January 1998 相似文献
674.
Hart-Davis Michael G. Laan Stendert Schwatke Christian Backeberg Björn Dettmering Denise Zijl Firmijn Verlaan Martin Passaro Marcello Seitz Florian 《Ocean Dynamics》2023,73(8):475-491
Ocean Dynamics - With the continued rise in global mean sea level, operational predictions of tidal height and total water levels have become crucial for accurate estimations and understanding of... 相似文献
675.
When drawing up a database for sunspots from a large collection of white-light films, a need for the automation of the process arises. The concepts used at the automation of the area measurements of sunspots are described. As an example, sunspot groups NOAA 5521 and 5528 are processed and the areas obtained are compared to the measurements published in the literature. Similar values are obtained, except umbral areas published by Steinegger et al. (1996) which are significantly larger than ours. We find that the differences may be attributed to the fact that the definition proposed by Steinegger et al. (1996) for the penumbra–umbra border of a sunspot is not equivalent to those used for the measurements of others of the umbral area. 相似文献
676.
T. Kılıç L. Ottemöller J. Havskov K. Yanık Ö. Kılıçarslan F. Alver M. Özyazıcıoğlu 《Journal of Seismology》2017,21(1):35-46
Based on the earthquake event data accumulated by the Turkish National Seismic Network between 2007 and 2013, the local magnitude (Richter, Ml) scale is calibrated for Turkey and the close neighborhood. A total of 137 earthquakes (Mw?>?3.5) are used for the Ml inversion for the whole country. Three Ml scales, whole country, East, and West Turkey, are developed, and the scales also include the station correction terms. Since the scales for the two parts of the country are very similar, it is concluded that a single Ml scale is suitable for the whole country. Available data indicate the new scale to suffer from saturation beyond magnitude 6.5. For this data set, the horizontal amplitudes are on average larger than vertical amplitudes by a factor of 1.8. The recommendation made is to measure Ml amplitudes on the vertical channels and then add the logarithm scale factor to have a measure of maximum amplitude on the horizontal. The new Ml is compared to Mw from EMSC, and there is almost a 1:1 relationship, indicating that the new scale gives reliable magnitudes for Turkey. 相似文献
677.
In 1991, a digital seismic monitoring network was installed in Iceland with a digital seismic system and automatic operation. After 20 years of operation, we explore for the first time its nationwide performance by analysing the spatiotemporal variations of the completeness magnitude. We use the Bayesian magnitude of completeness (BMC) method that combines local completeness magnitude observations with prior information based on the density of seismic stations. Additionally, we test the impact of earthquake location uncertainties on the BMC results, by filtering the catalogue using a multivariate analysis that identifies outliers in the hypocentre error distribution. We find that the entire North-to-South active rift zone shows a relatively low magnitude of completeness Mc in the range 0.5–1.0, highlighting the ability of the Icelandic network to detect small earthquakes. This work also demonstrates the influence of earthquake location uncertainties on the spatiotemporal magnitude of completeness analysis. 相似文献
678.
Jeffrey B. Ross Greg A. Ludvigson Andreas Möller Luis A. Gonzalez J. D. Walker 《中国科学:地球科学(英文版)》2017,60(1):44-57
Understanding of the role of atmospheric moisture and heat transport in the climate system of the Cretaceous greenhouse world represents a major challenge in Earth system science.Stable isotopic paleohydrologic data from mid-Cretaceous paleosols in North America,from paleoequatorial to paleoArctic latitudes,have been used to constrain the oxygen isotope mass balance of the Albian hydrologic cycle.Over the range from 40°-50°N paleolatitude,sideritic paleosols predominate,indicating paleoenvironments with positive precipitation-evaporation(P-E)balances.Local exceptions occur on leeward side of the Sevier Orogen,where calcic paleosols in the wedge-top depozone record paleoenvironments with negative P-E balances in the orographic rain shadow.Stratigraphic sections in the Wayan Formation of Idaho(WF)were sampled from the wedge-top depozone.The units consist of stacked m-scale mudstone paleosols separated by m-scale sandstone-siltstone beds.Sections were sampled for organic carbon isotope profiles,and B-horizons from 6 well-developed paleosols were sampled for detrital zircons to determine maximum depositional ages.The first of these from the WF has produced a U-Pb concordia age of 101.0±1.1 Ma.This same WF section has produced a stratigraphic trend of upwardly decreasingδ~(13)C values ranging from-24‰upwards to-27‰VPDB,suggesting correlation to the late Albian C15 C-isotope segment.Pedogenic carbonates from the WF principally consist of micritic calcite,with carbon-oxygen isotope values that array along meteoric calcite lines(MCLs)withδ~(18)O values that range from-9.47‰up to-8.39‰VPDB.At approximately 42°N paleolatitude,these MCL values produce calculated paleoprecipitation values of-8.12‰to-7.04‰VSMOW,a range that is consistent with the estimates produced from other proxies at the same paleolatitudes across North America.These results indicate that despite the orographic rain shadow effect,the processes of meridional atmospheric moisture transport in this locale were similar to those in more humid mid-latitude paleoenvironments elsewhere in the continent. 相似文献
679.
Forty-six mining-induced seismic events with moment magnitude between ?1.2 and 2.1 that possibly caused damage were studied. The events occurred between 2008 and 2013 at mining level 850–1350 m in the Kiirunavaara Mine (Sweden). Hypocenter locations were refined using from 6 to 130 sensors at distances of up to 1400 m. The source parameters of the events were re-estimated using spectral analysis with a standard Brune model (slope ?2). The radiated energy for the studied events varied from 4.7 × 10?1 to 3.8 × 107 J, the source radii from 4 to 110 m, the apparent stress from 6.2 × 102 to 1.1 × 106 Pa, energy ratio (E s/E p) from 1.2 to 126, and apparent volume from 1.8 × 103 to 1.1 × 107 m3. 90% of the events were located in the footwall, close to the ore contact. The events were classified as shear/fault slip (FS) or non-shear (NS) based on the E s/E p ratio (>10 or <10). Out of 46 events 15 events were classified as NS located almost in the whole range between 840 and 1360 m, including many events below the production. The rest 31 FS events were concentrated mostly around the production levels and slightly below them. The relationships between some source parameters and seismic moment/moment magnitude showed dependence on the type of the source mechanism. The energy and the apparent stress were found to be three times larger for FS events than for NS events. 相似文献
680.
Hèou Maléki Badjana Manfred Fink Jörg Helmschrot Bernd Diekkrüger Sven Kralisch Abel Akambi Afouda 《水文科学杂志》2017,62(7):1094-1113
This paper discusses the analysis and modelling of the hydrological system of the basin of the Kara River, a transboundary river in Togo and Benin, as a necessary step towards sustainable water resources management. The methodological approach integrates the use of discharge parameters, flow duration curves and the lumped conceptual model IHACRES. A Sobol sensitivity analysis is performed and the model is calibrated by applying the shuffled complex evolution algorithm. Results show that discharge generation in three nested catchments of the basin is affected by landscape physical characteristics. The IHACRES model adequately simulates the rainfall–runoff dynamics in the basin with a mean modified Nash-Sutcliffe efficiency measure of 0.6. Modelling results indicate that parameters controlling rainfall transformation to effective rainfall are more sensitive than those routing the streamflow. This study provides insights into understanding the catchment’s hydrological system. Nevertheless, further investigations are required to better understand detailed runoff generation processes.
EDITOR M.C. Acreman; ASSOCIATE EDITOR N Verhoest 相似文献