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Despite substantial rural-urban migration, 38.1 percent of the population of Poland still live in the countryside and the
total numbers are only 0.9mln fewer than in 1946. At present the rural population is increasing and the rate of natural increase
(though falling) is higher than in the towns though the productive age group is smaller. However, these human resources are
not being properly used and the results can be seen in terms of economic inefficiency, low living standards and a high level
of state support. Loss of jobs in factories and state farms results in welfare payments by the state and considerable 'hidden
unemployment' on small family farms where profitability is constrained by inefficient use of labour. Poverty among the rural
population is evident through a collapse of house building and considerable domestic overcrowding. However, conditions vary
considerably across the country and this must be reflected in the economic and social policies drawn up for the new administrative
regions introduced in 1999.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Summary Smoothing time series of measurements is usually employed to remove high frequency noise when it is necessary to interpolate
them for dates where no measurements are available, and also in an attempt to free the series from their short-term instability
in order to provide an improved representation of the measured quantity.
Two methods are currently used in connection with the Earth's rotation studies: Vondrak's algorithm and a moving average with
a Gaussian weighting function [Gaussian smoothing). This study describes their behaviour in terms of frequency filtering and
of the response in the time domain. Examples of their application to the Earth Rotation Parameters are given. 相似文献
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Wlodzimierz Kurek Dr. 《GeoJournal》1996,38(2):191-196
The Polish Carpathians is one of the regions with the best rural demographic and economic situation in Poland, as indicated by the growth of population, the very advantageous sex and age structure, the low unemployment rate and good housing standards. However, the situation in agriculture is complicated due to the unfavourable natural conditions of the mountainous terrain, the fragmentation of holdings and the low level of efficiency. On the other hand, tourism is a positive factor in the socio-economic transformation of the Carpathian countryside. Tourism was a significant activity even before the Second World War when lodgings were sought in private houses in many villages of the Sub-Tatra, Podhale Basin and the Silesian and Sacz Beskides. The villages currently active as tourist centres show the most dynamic development and the highest level of the socio-economic infrastructure. 相似文献
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One of the critical technological parameter in operation of aerated submerged fixed‐bed biofilm reactor (ASFBBR) is the control over process of biofilm detachment. Both, an excessive growth of biomass with its accumulation in the bioreactor and an exceeded biofilm detachment rate, cause serious operational and technological problems. The studies presented in this paper demonstrate that in an ASFBBR reactor with a PVC bed carrier media, an effective way to maintain a proper shear stress acting on the biofilm and causing its detachment could be an internal recirculation of wastewater instead of backwashing with wastewater or air flushing. In case of polishing of oil‐refinery wastewater with average COD loading rate equal to 9 g COD/(m2 day), the minimum value of the hydraulic loading rate in such reactor is 1.9 m3/(m2 h), at which there was no excessive growth of biofilms. Despite a significant decrease of the biofilms thickness and amount of biomass in the reactor, there was no significant decline in the efficiency of pollutant removal from oil‐refinery wastewater, which made it possible to obtain the quality of effluent at the outlet of the bioreactor significantly below the water permits and standards. 相似文献
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The focus of this paper is on the analysis of the influence of particles’ velocity distribution and their concentration on the sediment transport rate in bed-load from the Lagrangian perspective.Such aims are addressed by use of the relevant Lagrangian model of spherical saltating particles in which turbulence plays a significant role.The Monte Carlo approach is employed in the simulations to obtain the velocity and concentration of the saltating particles.Numerical simulations using two saltating particle models:(1) with;and(2) without particle-particle collisions are carried out.Based on the numerical results,we address the hypothesis that instead of averaged characteristics,the distributions of particles’ velocity and sediment concentration should be taken into account in the calculation of sediment transport rate.Moreover,our results also show that the interaction between particles during their collisions is the key for better understanding of the physics of sediment transport.All results are compared with well-known experimental formulae i.e.Meyer-Peter and Muller and Fernandez Luque and van Beek. 相似文献
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