Susceptibility of mice and rats to human Lamblia. Experimental study with the use of a cultivation method

The effects of pregnancy on the lymphocyte populations in the mouse have been studied. Though cell numbers decreased in the thymus and increased in the lymph nodes draining the parauterine area, no significant changes were seen in the proportions of thymus derived (theta allo-antigen positive) and bone marrow derived (Fc receptor positive) lymphocytes. The humoral response to sheep erythrocytes was suppressed during both syngeneic and allogeneic pregnancies following a decline coincidental with that of thymic mitotic activity. Though the observed immunosuppression could be explained by a selective lymphocyte depletion, it appears more likely to be a nonspecific effect of the steroid milieu of pregnancy.     

A partial fuel reloading schedule for nuclear reactors

This paper considers the effect of partial reloading of the nuclear fuel on the degree of uranium burn-out in the working fuel rods of a reactor. The condition of minimum cost of electrical energy is used to find the optimum fraction of the nuclear fuel to be renewed periodically in the reactor. Here it is kept in mind that the reloading of fuel rods is done with the reactor shut down.The formulas for determining the optimum reloading fraction are derived for an infinite reactor lattice, with recovery of spent rods. The numerical results are found to be applicable to the reactors of the First Atomic Electric Station and the I. V. Kurchatov Beloyarskoe Atomic Electric Station.     

Abstracts of Papers Deposited at Viniti

Journal of Engineering Physics and Thermophysics -     

Commissioning of the NPDGamma Detector Array: Counting Statistics in Current Mode Operation and Parity Violation in the Capture of Cold Neutrons on B4C and 27Al

The NPDGamma γ-ray detector has been built to measure, with high accuracy, the size of the small parity-violating asymmetry in the angular distribution of gamma rays from the capture of polarized cold neutrons by protons. The high cold neutron flux at the Los Alamos Neutron Scattering Center (LANSCE) spallation neutron source and control of systematic errors require the use of current mode detection with vacuum photodiodes and low-noise solid-state preamplifiers. We show that the detector array operates at counting statistics and that the asymmetries due to B₄C and ²⁷Al are zero to with- in 2 × 10⁻⁶ and 7 × 10⁻⁷, respectively. Boron and aluminum are used throughout the experiment. The results presented here are preliminary.     

Construction of a working area for the manipulation mechanism of simultaneous relative manipulation

Synthesis problems of handling mechanisms of simultaneous relative manipulation have been considered. The direct positional problem for the parallel structure mechanism of simultaneous relative manipulation has been solved. The operating space of the mechanism has been defined.