Castes, migration, immunogenetics and infectious diseases in south India

It has been said that the grandest genetic experiment of nature has been conducted in south India in the name of the caste system. One can expect the frequency of an infectious disease to be equal to the product of the frequencies of various indicated loci/alleles, whether physiological, hormonal or immunological, in an endemic area. The sympatrically isolated caste and sub-caste populations of southern India, with differing origins, migration patterns and breeding habits, differ significantly in their HLA and other immune repertoire and are ideal models to study and test this hypothesis. The prevalence of a number of major infectious diseases, including TB and leprosy, are reviewed in different communities in the light of their genetic history.     

Excitation of Van Kampen-case waves

The response of a fluid with a shear flow having a slightly curved profile to an external vertical impact force, harmonic with respect to the horizontal coordinate and concentrated in a narrow layer, is calculated. The cases of an ideal and a viscous fluid are considered.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 115–119, January–February, 1987.The author wishes to thank G. I. Barenblatt, M. A. Mironov, and S. A. Rybak for useful discussions.     

Boundary kinetic effects in the problem of slow flow over an evaporating heat-conducting spherical particle

It is shown that for sufficiently large values of the thermal conductivity of the condensed phase' as compared with the thermal conductivity of the vapor (/' Kn) the effects associated with the presence of a Knudsen layer on the evaporating surface must be taken into account in order to obtain a solution of the problem of a spherical particle in a slow (Re, 1) continuum (Knudsen number Kn 1) flow of its own vapor. The drag is calculated for various types of boundary conditions on the particle surface.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 134–139, March–April, 1987.In conclusion the authors wish to thank V. S. Galkin and M. N. Kogan for useful discussions.     

Stretching of squeezed liquid under the action of its own weight

The stretching of a liquid sample, squeezed out in the vertical direction from an aperture of an arbitrary form, is investigated. The problem of controlling the dimensions of the aperture or the rate of squeezing for obtaining samples of a given configuration is discussed.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 10–14, September–October, 1975.     

Oscillations of a wedge in a free stream with particular reference to parachutes

The phenomenon of coupled breathing and longitudinal oscillations of a wedge-mass system in a free stream is examined. As a first step the unsteady pressure distribution on the surface of the oscillating wedge is calculated. For dynamic equilibrium of the wedge-mass system, the moment about the apex of the wedge must be zero. This condition establishes the amplitude and phase relation between breathing and longitudinal oscillations. As a final step the equation of motion of the store is used to calculate the frequency of the breathing oscillations. This frequency is shown to be dependent on four parameters. These parameters include the Froude number, the rigging line length to wedge breadth ratio and the rigging line stiffness and damping. Current results are compared with Hume and Stevens [1] experimental results.     

Limiting energy characteristics of pulsed tea co2 lasers

The article presents the results of experimental studies on the determination of the characteristics of the process of absorption of large specific electrical energy densities in a wide range of pressures (0.1–0.5 atm CO₂?2N₂?0.5H₂). The presence of limitations (E₀/p ≥45 V/cm · torr, Q/p=? 1 J/cm³ · atm) which are responsible for the region of existence of a diffusional discharge was established, which made it possible to determine the relationship between the limiting electrical energy density which can be absorbed in the discharge, the initial parameters of the system, and the amount of radiated energy.     

Diffusion in multicomponent gaseous mixtures in a model of local thermodynamic equilibrium

Diffusion of chemical elements into an ionized multicomponent gaseous mixture is considered in a model of local thermodynamic equilibrium. A linear dependence of the mass flows of chemical elements and the heat flow on the temperature gradient, mass fractions of the chemical elements, and the electric field is obtained. An example is given of a calculation of the effective diffusion coefficients for a hydrogen-helium mixture.     

Conductor destruction in electrical explosion

Conductor damage has been examined when the current is switched off at various stages in electrical explosion. If the switching is fairly rapid, kink instability growth is accompanied by formation of vapor bubbles at the kinks within the volume of the liquid metal. Later switching results in vapor bubbles uniformly distributed along the conductor. Cumulative ejection occurs under certain conditions. A qualitative interpretation is given.     

Axisymmetric vortex source (sink)

A vortex analog is found for a potential three-dimensional source. The possibility of extending the known method of superposition to the case of axisymmetric vortex flows is indicated. Considered as an illustration is the axisymmetric homogeneous helical flow around a half-body. It is shown that the pressure is constant in an axisymmetric vortex stream without a circumferential velocity.