Kinetic Alfvén waves in extended radio sources

We study a model of extended radio sources (ERS), in particular, extragalactic jets and radio lobes, which are inhomogeneous and where noncompressive Alfvén and surface Alfvén waves (and not shocks and magnetosonic waves) are primarily excited. We assume that a negligible thermal population exists (i.e., the ion density at the low-energy cut-off of the power law distribution is greater than the ion density of the thermal population, if present). Due to internal instabilities and/or the interaction of the ERS with the ambient medium, surface Alfvén waves (SAW) are created. We show that even very small amplitude SAW are mode converted to kinetic Alfvén waves (KAW) which produce large moving accelerating potentials , parallel to the magnetic field. Neglecting nonlinear perturbations, and for typical physical parameters of ERS, we obtaine1 MeV. Wesuggest that these potentials are important in acceleration (e.g., injection energy) and reacceleration of electrons in ERS. We show that energy losses by synchrotron radiation can be compensated by reacceleration by KAW. The relation between KAW acceleration, and previously studied cyclotron-resonance acceleration by Alfvén waves, is discussed.     

Some comments on the asymptotic limit of antiproton-proton flux ratio at the top of the atmosphere

Using the leaky-box model the upper limit of the antiproton-proton flux ratio at the top of the atmosphere has been estimated from the latest primary nucleon spectrum and accelerator data on inclusive reactions. The estimated value of flux ratio comes out to be (3.6±0.3)×10^–4 is in accord with the previous results but still far from the measurements.     

X-ray and ultraviolet observations of AG Draconis during quiescence and outburst

We describe the first X-ray monitoring of a symbiotic star during phases of enhanced activity. AG Dra is a Pop II object with a composite spectrum, characterized by a cool K-type component, prominent high ionization emission lines and a strong UV continuum which is attributed to a hot dwarf companion. Periodic variability of the UV radiation during minimum could be attributed to the orbital motion of the system. In April 1980 HEAO-2 detected an intense, soft X-ray flux from AG Dra, stronger than in other symbiotic stars. After one major outburst of November 1980, which continued until 1983, two more outbursts occurred in February 1985 and January 1986, and coordinated X-ray (EXOSAT) and ultraviolet (IUE) observations were organized to study the behaviour of AG Dra during different activity phases. EXOSAT observations made during decline after the 1985 outburst, revealed a weak X-ray flux in the Thin Lexan filter of the Low Energy dedtector. Observations made during minimum, in June and November 1985, at phases 0.22 and 0.50 of the UV light curve, disclosed the presence of an intense X-ray flux, which was not occulted in November. AG Dra was again observed with EXOSAT in February 1986 when the stellar luminosity was still at maximum. No X-ray flux was detected, in spite of the prominent, high ionization UV spectrum observed with IUE.A detailed discussion of the X-ray and ultraviolet results on AG Dra in the light of possible models is in progress.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986.     

Ultraviolet solar irradiance measurement from 200 to 358 nm during spacelab 1 mission

The paper presents the results obtained from the UV-spectrometer of the Solar Spectrum Experiment during the Spacelab 1 mission in December 1983. The irradiance data concern 492 passbands, which are located between 200 and 358 nm at almost equidistant wavelengths separated by about 0.3 nm. The passbands have a well-defined, bell-shaped profile with a full width at half maximum of about 1.3 nm. The data, which have an error budget between 4 and 5%, agree closely with the spectral distributions observed by Heath (1980) and Mentall et al. (1981) and confirm that the solar irradiance and the fluxes of Sun-like stars show about the same spectral distribution down to at least 240 nm.     

Group Doppler effect in anisotropic plasmas

In anisotropic plasmas, the radiative power emitted and the power observed per unit solid angle should be calculated along the direction of the group velocityv _g . The two power functions referred differ by a product of two factors: one is the group Doppler factor and the other is the squeezing effect of the radiative energy due to the dependence ofv _g on direction. In this paper, the group Doppler factor is derived using two different methods, and the relevant physical concepts are analyzed in details. A number of numerical examples pertaining to astrophysical situations are presented, to illustrate the significance of the group Doppler effect with respect to the wave Doppler effect which is valid in isotropic media.     

Outmigration patterns in development transition of rural areas

Using a broadened concept of migration, which includes circulatory migration and commuting, this paper maintains that the patterns of outmigration vary a great deal when the level of development of a rural area is treated as an independent variable. This study uses a stratified conditional sample of 192 households selected from 3 areas: 53 households from a low developed (LDL) area, 56 from a medium (MDL), and 83 from a high (HDL). Data were collected by personal observation, interview, and genealogical methods at both the household and individual level. The households are divided into 3 main categories: 1) non-migrating, 2) commuting only, and 3) migrating (which is further divided into migrating within and migrating outside the boundaries of the district). Results show that 1) 37.51% of household members neither commute nor have migrated outside the village; 2) using the narrow definition of migration, only 10% of males over age 15 migrate, while including commuting in the definition increases the percentage to 40; 3) proportions of non-migrating households decrease from 58.4% for the LDL, to 35.7% for the MDL, to 25.3% for the HDL area; 4) the proportion of commuting only households increases from 26.4% for the LDL, to 35.7% to the MDL, and 55.4% for the HDL area; 5) 15.2% of households in the LDL, 28.6% in the MDL, and 19.3% in the HDL area experience a permanent change in residence; 6) as development accelerates, the overall volume of outmigration increases; 7) the flow of migration from rural to rural areas is mostly limited to the MDL area, while cityward migration increasingly occurs on both LDL and HDL areas; 8) the median age of commuters increases with rising levels of development; and 9) almost all migrants from the LDL area are employed in low prestige occupations, most from the HDL area have higher prestige jobs, and those from the MDL area have both high and low prestige jobs.     

Education as a determinant of fertility: a case study of Kullu Town

Using a sample of 885 females (1/2 of all married women of reproductive age), this study examines the role of education as a determinant of fertility among couples in Kullu town of Himachol Pradesh, India. Of the 885 respondents, only 149 were illiterate. The average family size was 2.88. Findings reveal that 1) the average family size was largest for illiterate respondents (3.57) and for illiterate males (3.76); 2) average family size declined consistently after the middle level of education to 1.29 for post graduate respondents and 2.33 for post graduate males; 3) a negative correlation exists between fertility and education of both husband and wife, with the wife's education having a stronger negative correlation with fertility; and 4) couples with an educational level of matriculation and above have a distinctly smaller family size than those less educated.     

Distribution and fluxes of metals in the St. Lawrence River from the outflow of Lake Ontario to Québec City

Six anchor stations in the St. Lawrence River from the outflow of Lake Ontario to Quebec City, were occupied for ca. 24 hours in June 1987 during low flow conditions. Samples of water and suspended particulate matter were separated by continuous-flow centrifugation, and were collected every two hours.During this sampling period, fluxes of dissolved forms of zinc, copper and nickel increased in Lac St. François and downstream relative to the sum of the fluxes for the two upstream stations at the outflow of Lake Ontario. Increases in the flux of dissolved zinc and copper were pronounced below Montreal and above Lac St. Pierre. For particulate forms of metals, all five metals show that there are significant inputs in the section of the St. Lawrence River between Lac St. François and the station just above the entrance to Lac St. Pierre.The average concentrations of dissolved cadmium, lead, zinc, copper and nickel ranged from 7–23 ng/l; 9–35 ng/l; 0.434–0.939 g/l; 0.15–0.89 g/l and 0.58–1.12 g/l respectively.Regression analysis of the dissolved and particulate metal concentrations suggests that the concentration of dissolved cadmium, lead, zinc and nickel can be predicted from the regression equation and the determination of particulate metal concentration. This prediction appears to be independent of the suspended particulate matter concentration which varies from ca. 1 to 10 mg/l from the outflow of Lake Ontario to Québec City.     

High pressure experimental calibration of the olivine-orthopyroxene-spinel oxygen geobarometer: implications for the oxidation state of the upper mantle

Synthetic spinel harzburgite and lherzolite assemblages were equilibrated between 1040 and 1300° C and 0.3 to 2.7 GPa, under controlled oxygen fugacity (f _{O 2}). f _{O 2} was buffered with conventional and open double-capsule techniques, using the Fe−FeO, WC-WO₂-C, Ni−NiO, and Fe₃O₄−Fe₂O₃ buffers, and graphite, olivine, and PdAg alloys as sample containers. Experiments were carried out in a piston-cylinder apparatus under fluid-excess conditions. Within the P-T-X range of the experiments, the redox ratio Fe³⁺/ΣFe in spinel is a linear function of f _{O 2} (0.02 at IW, 0.1 at WCO, 0.25 at NNO, and 0.75 at MH). It is independent of temperature at given Δlog(f _{O 2}), but decreases slightly with increasing Cr content in spinel. The Fe³⁺/ΣFe ratio falls with increasing pressure at given Δlog(f _{O 2}), consistent with a pressure correction based on partial molar volume data. At a specific temperature, degree of melting and bulk composition, the Cr/(Cr+Al) ratio of a spinel rises with increasing f _{O 2}. A linear least-squares fit to the experimental data gives the semi-empirical oxygen barometer in terms of divergence from the fayalite-magnetite-quartz (FMQ) buffer:

Geochemical specialization of the tin-bearing granitoid massifs of NW Bohemia

The geochemistry of Hercynian tin-bearing granitoid massifs of the Krune hory Mts. (Erzgebirge), Slavkovský les Forest (Kaiserwald) and Smriny (eastern Fichtelgebirge) is compared by statistical processing of 270 analyses including a wide spectrum of major and trace elements. Seven different types of granites are distinguished. Out of these, five types represent the successive differentiation of the largest massif of NW Bohemia: the Karlovy Vary (Karlsbad) massif. This comprises strongly differentiated peraluminous granites evolving towards extreme Li-Rb-Cs-F-and Sn-enrichment in the youngest members, which are albite-topaz-zinwaldite lithium granites. The sixth and seventh types are different from the former by their location in the eastern Krune hory and tectonic setting, and they display geochemical features of anorogenic granites: they are metaluminous albite-zinwaldite granites with marked enrichment of Nb, Y, and HREE in addition to Li, Rb, Cs, F and Sn, indicating contamination by sub-crustal material. Sn-W mineralizations, including flat peri-contact greisen bodies, steep greisen veins and tourmalinized phyllites, are all intimately associated with the most strongly differentiated granites — the Li-granite and the Cinovec-granite respectively.