About the problem of motion of n gyrostats: I. The first integrals     

R. Cid  A. Vigueras 《Celestial Mechanics and Dynamical Astronomy》1985,36(2):155-162

In this paper, the problem of the motion of n gyrostats in a central field, with relative momenta _k ^r (k=1, 2, ..., n) functions of the time, is considered.In these conditions, the existence of the linear and angular momentum integrals is established.Moreover, a sufficient condition for the existence of the Jacobi's Integral is given. This study generalizes the results given by Duboshin for n rigid bodies.  相似文献   

Northern settlement family-style: labor planning and population policy in Noril'sk     

Bond AR 《Soviet geography》1985,26(1):26-47

This paper reviews labor planning and population policies in Noril'sk, a mining and metallurgical settlement in northern Siberia. When the settlement was established in 1935, planners were lacking in ideas about how to recruit workers to staff the mines and smelters and how to retain the labor force once it was in place. From 1935-79, planners followed a forced labor policy dependent upon the labor of prisoners. However, this solution was not adequate for meeting the manpower needs of an economy undergoing rapid technological sophistication. Northern wage increments were introduced after 1945 to recruit skilled workers from other regions. These increments built up over a 4-year period to a maximum of 80% of base pay. A special cost of living bonus was also awarded. Although these inducements facilitated labor recruitment, labor retention remained a major problem. Surveys indicated that workers would prefer improvements in housing and social services to further wage increases. Thus, policy was directed at the housing shortages, poor medical care, and inadequate child care facilities in Noril'sk. Such improvements facilitated labor retention but also contributed to overpopulation. The population doubled between 1956-80, exceeding 180,000 in the latter year. In the early 1980s, selective measures toward population control were implemented to ensure maintenance of living standards (e.g., encouragement of older workers to leave the area upon retirement, more careful screening of recruits). The goal is to stabilize city size at around 250,000. The Noril'sk case illustrates that quality of life investments can alleviate labor retention problems even in the harshest physical environments. Recent policies have advocated productivity-enriching technologies that do not require increments in the labor force.  相似文献   

Estimating proximate populations for an extensive set of locations in Australia     

Cocks KD  Walker PA 《The Australian geographer》1985,16(4):295-300

"The paper reports the use of Australian Resources Information System to calculate two proximate populations (people living within (i) 150 and (ii) 500 km) for the centroids of each of 3,000 half by half degree geodetic grid cells covering Australia. The use of proximate population data is exemplified by computing a map of the eighteen regions collectively containing a maximum fraction of the Australian population." The data used are from the 1981 census.  相似文献   

Population development in Greater Santiago between 1970 and 1982: an analysis of district census results     

Bahr J  Mertins G 《Erdkunde》1985,39(3):218-238

"An attempt is made in the light of an analysis of population changes occurring in several sub-districts of Greater Santiago in the period between the last population censuses of 1970 and 1982, based on small-area census units (distritos and communas) to draw attention to the effects on the spatial growth of the city resulting from changed conditions in the political and juridical sphere since the change of power in 1973." The effect of changes in government policy concerning the liberalization of the property market and the illegal occupation of land are noted. (summary in ENG)  相似文献   

Nonlinear wave conversion in electron-positron plasmas     

M. E. Gedalin  J. G. Lominadze  L. Stenflo  V. N. Tsytovich 《Astrophysics and Space Science》1985,108(2):393-400

Wave conversion mechanisms causing large-frequency shifts are considered for an electron-positron plasma in a strong magnetic field. In particular, we discuss the effects of the nonlinear erenkov as well as the cyclotron resonances in order to associate pulsar radio-emissions with our present model for nonlinear conversion of high-frequency radiation into the low-frequency region.  相似文献   

A note on the energy loss from pulsars     

A. Čadež 《Astrophysics and Space Science》1985,109(2):399-402

We respond to comments made in a recent letter by Karimet al. (1984), and show that the examples of interstellar absorption at2800 Å that they have presented so far can all be attributed to overexposure of the IUE detectors.  相似文献   

Distance estimate of M31 based on the size distribution of Hii regions and dark clouds     

I. A. Issa 《Astrophysics and Space Science》1985,113(2):317-323

The size distribution of dark clouds and of H II regions were used to derive a distance of 440±22 kpc for M31. Some galactic H II regions and dark clouds were combined with the same ingredients in M31 to study the mass spectrum of both phenomena. A gas to dust ratio of 10001 has been derived for M31. Radii of the classical H II regions as derived in this work using distance of 440 kpc agrees with the galactic classical H II region radii.  相似文献   

Gravitational instability of interstellar magnetic clouds     

K. K. Ghosh  J. C. Bhattacharyya 《Astrophysics and Space Science》1985,117(1):89-94

The gravitational instability of a nonrotating isothermal gaseous disk permeated by a uniform frozen-in magnetic field is investigated using a fourth-order perturbation technique. From the results it is found that the disk is stable whenn/B ₀ < (4/3³ G)^–1/2, wheren andB are the column density of the disk and unperturbed magnetic field, respectively, andG is the gravitational constant. The disk is gravitationally unstable only whenn/B ₀ > (4/3³ G)^–1/2.  相似文献   

On the collision probability for comets with the Sun     

R. A. Serafin 《Celestial Mechanics and Dynamical Astronomy》1985,36(3):273-280

We consider the collision probability for comets with the Sun under the suppositions of different velocity distributions and various initial conditions. We solve the problem applying Laplace's method and using Schiaparelli's hyperboloid of visibility. The probabilities obtained in this manner are given separately for elliptic and hyperbolic orbits.  相似文献   

Propagation of the cosmic-ray iron group at intermediate energies     

C. Baixeras  M. Casas  F. Fernandez  A. Vidal-Quadras  M. Ortega 《Astrophysics and Space Science》1983,96(2):321-331

Elemental abundances of the VH group of cosmic radiation have been measured in the energy interval 250–550 MeV nucl^–1 in a balloon exposure at Sioux Falls (South Dakota) of a plastic detector LeXAN stack. The so obtained abundances have been extrapolated to the sources in the frame of the homogeneous model correcting for energy loss. After taking into account solar modulation, the best fit to model values has led to a escape mean free path _e = 5E ^–0.4 g cm^–2, whereE is the energy in GeV nucl^–1, forE>1 GeV nucl^–1, and a constant _e = 5 g cm^–2 forE1 GeV nucl^–1. When turning to the diffusion model, also including an energy loss term, a diffusion coefficientD=3×10²⁸ cm² s^–1 has been estimated.  相似文献