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51.
The effects of air transportation on the movement of labor 总被引:1,自引:0,他引:1
The effects of the deregulation of airlines markets and the new technologies that have been introduced into air transportation
have been heavily studied. Much of this analysis has been on the impacts on the industry and the immediate welfare implications
for passengers and, to a lesser extent, cargo consignors. This study looks at the longer-term effects of the modern air transportation
system on labor markets and labor migration. The growth of the service sector, the emergence of more flexible manufacturing
techniques, the reduction in trade-barriers, and the creation of more sophisticated financial markets have led to greater
mobility in production and in capital movement. This has been explored to some extent. Labor is, however, also more mobile
- for example, since the admission of Poland to the European Union some 465,000 Polish workers have joined the UK labor market.
Air transportation facilitates easier migration, makes short-term, long-distance migration viable, and allows migrants to
maintain contact with their home country. Within larger countries, such as the US, there has also been a growth in long distance
“week-day” migration as spouses work in different parts of the country to be reunited at weekends. The study makes use of
aggregate data to look at trends in international labor movements particularly concerning the European situation, and, to
a lesser extent, at recent developments within the US. It is concerned both with what is going on in terms of the use being
made of air transportation by migrants and the light that this may shed on migration theory.
相似文献
Kenneth John ButtonEmail: |
52.
Abstract. Using principal component analysis, the zooplanktonic communities of the divergence zone in the northwestern sector of the Alboran Sea were studied. The study was based on 35 vertical trawls in the 200 metres superficial level. The two first components account for 65 % of the total variance. The first component is a contrast between a warm water coastal community (characterized by low specific diversity and the abundance of Cladocera and Copepoda such as Acartia clausi, Centropages chierchiae and Temora stylifera) and a community of cold subsuperficial water distinguished by high specific diversity and a low number of individuals, one of its most characteristic elements being the eggs and larval stages of the Conostomasidae Maurolicus muelleri. The second component appears to be associated with an ecotone between the communities previously cited, and with a specific grouping (Rhincalanus nasutus, Eucalanus monachiis, Pseudocalanus elongatus, Temora longicornis , etc.) resulting from the peripheral displacement of subsuperficial elements brought to the surface by the cyclonic circulation of water masses between the Atlantic current and the Spanish coast. 相似文献
53.
A high sensitivity, low volume HPLC method to determine soluble reactive phosphate in freshwater and saltwater 总被引:1,自引:0,他引:1
A reverse phase High Performance Liquid Chromatography (HPLC) method was developed to detect soluble reactive phosphate (SRP) in marine and freshwater samples. This technique is scalable over a range of sample volumes from 10 μl to 10 ml, requires minimal sample preparation, and responds linearly from 1 nM to 100 μM (R2>0.964). Standard Murphy–Riley molybdenum blue reagents were used to react with phosphate in samples for analysis. Solid phase extraction tubes were used to clean the mixed complexing reagent prior to combining the reagent with samples. The method was applied to freshwater samples collected in July 2001 along an Andean mountain stream located in the Eastern Cordillera (2400 m) of Peru and marine samples collected in January 2002 within the low marsh of the estuarine Nueces Delta System, Texas Coastal Bend. For method comparison, field samples were analyzed using a standard manual spectrophotometric method. Field sample phosphate concentrations produced from each method were nearly identical. This method offers the advantages of low sample volume (1 ml or less) with high sensitivity, precision, and potential automation. 相似文献
54.
Jaime Klapp 《Astrophysics and Space Science》1984,106(2):215-229
In a previous paper (Klapp, 1983) we have described the evolution of metal-free mass-losing very massive stars (VMS) in the 500–10 000M
range. The present paper concerns to the nucleosynthesis and mass loss aspects of the hydrogen- and helium-burning phase. Through radiation driven winds, the star losses 20–40% of its mass as helium and 1% as carbon and oxygen. The results show that VMS cannot produce the cosmological helium abundance without overproducing heavier elements. The high oxygen yield of VMS makes them the best candidates for producing an oxygen overabundance in old Population II stars. 相似文献
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ABSTRACT Changes in growing season length (GSL) are of concern for agricultural, phenological, economic, epidemiological, and bioclimatological reasons. This research identifies spatial and temporal changes over the last several decades in GSL, along with the day-of-year of the last spring freeze and first autumn freeze, for the northeastern United States – a region particularly susceptible to such changes due to the large population and intense economic activities. Results suggest that growing season has significantly increased in length since 1980 as compared to prior to 1980, and both spatial and temporal variation in GSL has decreased for the region over time. Changes to GSL for this region are driven more by a shift in the first autumn freeze date than the last spring freeze date. The areas of greatest increase in GSL in the pre- vs. post-1980 period tend to be in the high elevations, near large water bodies, and near the largest cities. Results will assist environmental planners as they prepare mitigation and adaptation strategies amid a changing environment. 相似文献
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59.
Vega Anthony J. Miller Paul W. Rohli Robert V. Heavilin Jason 《Natural Hazards》2021,105(2):1281-1297
Natural Hazards - Nuisance flooding (NF; also known as high-tide, or “sunny day” flooding) is an increasingly prevalent phenomenon afflicting coastal developments worldwide. NF often... 相似文献
60.
de Luna Rejane Maria Rodrigues dos Anjos Garnés Silvio Jacks da Silva Pereira Cabral Jaime Joaquim dos Santos Sylvana Melo 《Natural Hazards》2021,106(3):1821-1837
Natural Hazards - Recife Metropolitan Region, in the northeast of Brazil, is formed by a coastal plain bounded by hills and by the Atlantic Ocean. Recife Metropolitan Region has about 4 million... 相似文献