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111.
Kalle Emil Holst Hansen 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2015,115(2):133-141
This paper investigates the mobility of highly skilled labour, using doctors in public hospitals in Denmark as an example. From the perspective of regional development, the concentration of human capital is one of the contributors to regional growth and consequently to inequality between places, being associated most often with differences in economic growth between regions. The decentralisation of highly skilled public jobs to even out the concentration of human capital could be one way to stimulate growth outside city regions. However, such initiatives are somewhat dependent upon the cooperation of the highly skilled public employees, whose preferences have been little studied thus far. Based on data from a survey of 1600 publicly employed doctors, PLUM regression modelling was applied to test the relative significance of four professional preferences influencing choice of workplace. It was found that professional preferences have different influences on doctors’ choices, depending on their place of residence measured in terms of a location’s population density. The paper concludes that opportunities in employment depend on one’s stage in life and can serve to explain choices and mobility among highly skilled public employees. 相似文献
112.
L. Gordon Medaris Jr. Lukáš Ackerman Emil Jelínek Tomáš Magna 《International Journal of Earth Sciences》2015,104(8):1925-1956
113.
The study presents results on the informativity and spatial variation of soil aggregation characteristics in one of the Critical Zone Observatories (CZO) in Europe – Fuchsenbigl, Austria. Water stable aggregates of different size were measured, and strong relationships between soil aggregation estimates were found. The horizontal variation of water stable aggregates at particular depths can be explained by certain vertical heterogeneity of the soil profiles in space. The water stable aggregates in 1–3 mm size dry aggregates in the upper layer vary from 44% to 76% under native vegetation, drop to 1% under intensive cultivation, and comprise 19% in land not tilled for 5 years. The results allow linking the characteristics of soil structure with other biotic and chemical properties for better estimation of the driving forces for soil aggregate formation. 相似文献
114.
115.
This paper evaluates the renaturation activities applying the quantification of vegetation cover (VC), the site suitability analysis (SSA) based on the predefined criteria (slope steepness category (SSC), soil erodibility factor (K) and VC) and soil erosion model (SEM) results within the terrain units (TUs) along pipeline rights-of-way (RoW). Quantification of VC percentage is performed to assess the overall restored VC from 2005 to 2007. The results of the quantitative analysis in 2007 show that the total area of restored VC is 10.7 km2, and 8.9 km2 still needs to be restored to comply with the environmental acceptance criteria. As a result of SSA, TUs were prioritized by erosion vulnerability and this allowed to better understand the landscape behaviour in regards to erosion processes. SEM provided more detailed predictions of erosion classes falling into TUs. SEM identified 40% of erosion sites occurred from 2005 to 2010. 相似文献
116.
Unmanned aerial vehicles (UAV) for assessment of qualitative classification of Norway spruce in temperate forest stands 总被引:1,自引:0,他引:1
AbstractThe study investigates the potential of UAV-based remote sensing technique for monitoring of Norway spruce health condition in the affected forest areas. The objectives are: (1) to test the applicability of UAV visible an near-infrared (VNIR) and geometrical data based on Z values of point dense cloud (PDC) raster to separate forest species and dead trees in the study area; (2) to explore the relationship between UAV VNIR data and individual spruce health indicators from field sampling; and (3) to explore the possibility of the qualitative classification of spruce health indicators. Analysis based on NDVI and PDC raster was successfully applied for separation of spruce and silver fir, and for identification of dead tree category. Separation between common beech and fir was distinguished by the object-oriented image analysis. NDVI was able to identify the presence of key indicators of spruce health, such as mechanical damage on stems and stem resin exudation linked to honey fungus infestation, while stem damage by peeling was identified at the significance margin. The results contributed to improving separation of coniferous (spruce and fir) tree species based on VNIR and PDC raster UAV data, and newly demonstrated the potential of NDVI for qualitative classification of spruce trees. The proposed methodology can be applicable for monitoring of spruce health condition in the local forest sites. 相似文献
117.
Pavla Kováříková Wolfgang Siebel Emil Jelínek Miroslav Štemprok Václav Kachlík František V. Holub Vratislav Blecha 《International Journal of Earth Sciences》2010,99(3):545-565
Mafic and intermediate intrusions occur in the Slavkovsky les as dykes, sills and minor tabular bodies emplaced in metamorphic
rocks or enclosed in late Variscan granites near the SW contact of the Western Krušné hory/Erzgebirge granite pluton. They
are similar in composition and textures to the redwitzites defined in NE Bavaria. Single zircon Pb-evaporation analyses constrain
the age of a quartz monzodiorite at 323.4 ± 4.4 Ma and of a granodiorite at 326.1 ± 5.6 Ma. The P–T range of magma crystallization is estimated at ~1.4–2.2 kbar and ~730–870°C and it accords with a shallow intrusion level
of late Variscan granites but provides lower crystallization temperatures compared to the Bavarian redwitzites. We explain
the heterogeneous composition of dioritic intrusions in the Slavkovsky les by mixing between mafic and felsic magmas with
a minor effect of fractional crystallization. Increased K, Ba, Rb, Sr and REE contents compared to tholeiitic basalts suggest
that the parental mafic magma was probably produced by melting of a metasomatised mantle, the melts being close to lamprophyre
or alkali basalt composition. Diorites and granodiorites originated from mixed magmas derived by addition of about 25–35 and
50 vol.%, respectively, of the acid end-member (granite) to lamprophyre or alkali-basalt magma. Our data stress an important
role of mafic magmas in the origin of late Variscan granitoids in NW Bohemian Massif and emphasize the effect of mantle metasomatism
on the origin of K-rich mafic igneous rocks. 相似文献
118.
Jaromír Ulrych Emil Jelínek Zdeněk Řanda Felicity E. Lloyd Kadosa Balogh Ernst Hegner Jiří K. Novák 《Chemie der Erde / Geochemistry》2010,70(4):319-333
High-Ti melanephelinite (3.8–5.9 wt% TiO2), medium-Ti (phono)tephrite (2.7–3.1 wt% TiO2), and low-Ti olivine melanephelinite/basanite (1.9–2.3 wt.% TiO2) are subordinate rock types in the central European Cenozoic Volcanic Province. A contrasting melanephelinite to (phono)tephrite series occurs in the Lou?ná–Oberwiesenthal Volcanic Centre (37–28 Ma) and also as satellite volcanic bodies (26–12 Ma) together with olivine melanephelinite/basanite (17–20 Ma) on the southwestern periphery of the Kru?né hory mountains (Erzgebirge). The volcanic rocks intrude the Variscan basement of the uplifted shoulder of the Oh?e/Eger Rift in the Kru?né hory mountains of the Bohemian Massif. Low Mg# (44–59) and Cr, Ni contents and enrichment of LILE, Zr, Hf, Nb, Ta, U, Th and LREE in the high-Ti melanephelinites contrast with the composition of primitive low-Ti olivine melanephelinites/basanites displaying high Mg# (63–74) and high contents of compatible elements. The high-Ti melanephelinites reveal a wide range in initial 87Sr/86Sr of ca. 0.7034–0.7038 and εNd of 2.4–4.9. The low-Ti melanephelinites show an overlapping range of initial 87Sr/86Sr of ca. 0.7035–0.7036 and εNd of 4.3–5.5. The large variation in initial 87Sr/86Sr ratios at similar εNd values in those rock types is interpreted as evidence for melting of metasomatized lithospheric mantle sources comprising K-bearing phases with radiogenic Sr. Modification of the olivine-free alkali basaltic magmas by differentiation or crustal contamination could give rise to the medium-Ti (phono) tephrites. The initial isotope ratios of all samples are consistent with HIMU-mantle sources and contributions from lithospheric mantle. The olivine-free melanephelinitic rocks often contain alkali pyroxenite–ijolite xenoliths with initial 87Sr/86Sr ratios of ca. 0.7036 and εNd of 3.0. We interpret these xenoliths as samples of an intra-crustal alkali complex derived from similar mantle sources as those for the basaltic volcanic rocks. 相似文献
119.
Stranded gas is natural gas in discovered fields that is currently not commercially producible for either physical or economic
reasons. This study examines stranded gas from Russia and Central Asia and the role it can play in addressing Europe’s growing
demand for imported natural gas requiring additional volumes of gas in excess of 130 trillion cubic feet. We find sufficient volumes of stranded gas in fields in the Central
Asian state of Turkmenistan in the Amu-Darya Basin and in Russian fields in the West Siberian Basin. The analysis focused
on the estimated cost of extraction and delivery to a single market location for various concentrations of gas in stranded
gas fields in Central Asia and Russia. At import prices of 10 per million British thermal units (MMBTU), there are sufficient gas resources in stranded fields that can be commercially developed and delivered to the European market. If, however, imported gas prices fall below10 per million British thermal units (MMBTU), there are sufficient
gas resources in stranded fields that can be commercially developed and delivered to the European market. If, however, imported
gas prices fall below 7 per MMBTU, most of the stranded gas evaluated from West Siberia will not be commercial. The costs
of delivering gas from the largest stranded gas fields in Turkmenistan and Azerbaijan were calculated to be greater than 30%
below the costs of delivering gas from the largest stranded gas fields in Russia, which are located in the Yamal Peninsula.
Central Asian gas producers, particularly those east of the Caspian Sea, have limited market options due to the near monopoly
position that Gazprom holds in transporting pipeline gas from east of Europe. This study examines several additional options
to supply gas to Europe by reviewing expected delivered costs from North African and Atlantic basin suppliers. 相似文献
120.