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This paper focuses on the use of the provision of public housing in Israel as a political measure, in addition to its benign role of providing shelter. In the early stages of Jewish settlement in the country the Right controlled most towns and cities, while Labour was engaged in building a rural base. As urban growth attracted many of the newly arrived workers, Labour found it necessary to become politically active in the urban sphere. This has been done through the provision of a variety of services, among which was the provision of housing with a view to recruiting their political support. Two strategies were adopted. One was the penetration of existing towns by building public housing estates, the other was the establishment of new urban centres. These strategies have enabled Labour to attain local political hegemony in many cities, but while the provision of public housing proved to be as effective political tool in the short run, it has failed to secure a lasting impact. 相似文献
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Enzo Branchini Amiram Eldar Adi Nusser 《Monthly notices of the Royal Astronomical Society》2002,335(1):53-72
We present extensive tests of the fast action method (FAM) for recovering the past orbits of mass tracers in an expanding universe from their redshift-space coordinates at the present epoch. The tests focus on the reconstruction of present-day peculiar velocities using mock catalogues extracted from high-resolution N -body simulations. The method allows for a self-consistent treatment of redshift-space distortions by direct minimization of a modified action for a cosmological gravitating system. When applied to ideal, volume-limited catalogues, FAM recovers unbiased peculiar velocities with a one-dimensional, 1σ error of ∼220 km s−1 , if velocities are smoothed on a scale of 5 h −1 Mpc. Alternatively, when no smoothing is applied, FAM predicts nearly unbiased velocities for objects residing outside the highest density regions. In this second case the 1σ error decreases to a level of ∼150 km s−1 . The correlation properties of the peculiar velocity fields are also correctly recovered on scales larger than 5 h −1 Mpc. Similar results are obtained when FAM is applied to flux-limited catalogues mimicking the IRAS PSC z survey. In this case FAM reconstructs peculiar velocities with similar intrinsic random errors, while velocity–velocity correlation properties are well reproduced beyond scales of ∼8 h −1 Mpc. We also show that FAM provides better velocity predictions than other, competing methods based on linear theory or the Zel'dovich approximation. These results indicate that FAM can be successfully applied to presently available galaxy redshift surveys such as IRAS PSC z . 相似文献
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Amiram Roffman 《Pure and Applied Geophysics》1972,97(1):175-182
Summary An instrument for use with a captive balloon has been developed for the investigation of the vertical distribution of222Rn and its daughter ions of high mobility. The system consists of a light weight ion collector of the Gerdien type and an automatic air sampler. Simultaneous collections of222Rn and its daughter ions having mobilities of known limits makes it possible to determine the concentration of the radioactive ions relative to the ambient concentration of222Rn in different atmospheric conditions in the air layer adjacent to the ground where aircraft and tower measurements are not practicable. Vertical profiles taken over a mountain ridge in a well-mixed atmosphere show almost constant concentrations of222Rn and its daughter ions with altitude. In some cases a slight increase in the concentrations of222Rn and its daughter ions with altitude has been observed. The radioactive ion concentration relative to the ambient concentration of222Rn in the boundary layer is of the order of 3%. 相似文献
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