Results from the Apollo passive seismic experiment

Recent results from the Apollo seismic network suggest that primitive differentiation occurred in the outer shell of the moon to a depth of approximately 300 km; and the central region of the moon is presently molten to a radius of between 200 and 300 km. If early melting to a depth of 300 to 400 km was a consequence of accretional energy, very short accretion times are required. The best model for the zone of original differentiation appears to be a crust 40 to 80 km thick, ranging in composition from anorthositic gabbro to gabbro; overlying an ultramafic cumulate (olivine-pyroxene) about 250 km thick. The best candidate for the molten core appears to be iron or iron sulphide. A new class of seismic signals has recently been identified that may correspond to shallow moonquakes. These are rare, but much more energetic than the more numerous, deep moonquakes

Results from the Apollo passive seismic experiment

Recent results from the Apollo Seismic Network suggest that primitive differentiation occurred in the outer shell of the moon to a depth of approximately 300 km and the central region of the moon is presently molten to a radius of between 200 and 300 km. If early melting to a depth of 300 to 400 km was a consequence of accretional energy, very short accretion times are required. It was shown that the best model for the zone of original differentiation is a crust 40 to 80 km thick, ranging in composition from anorthositic gabbro to gabbro, and overlying an ultramafic cumulate about 250 km thick. The best candidate for the molten core appears to be iron or iron sulphide. A new class of seismic signals recently were identified that may correspond to shallow moonquakes. These are rare, but much more energetic than the more numerous, deep moonquakes

A guide for performing system safety analysis

A general guide is presented for performing system safety analyses of hardware, software, operations and human elements of an aerospace program. The guide describes a progression of activities that can be effectively applied to identify hazards to personnel and equipment during all periods of system development. The general process of performing safety analyses is described; setting forth in a logical order the information and data requirements, the analytical steps, and the results. These analyses are the technical basis of a system safety program. Although the guidance established by this document cannot replace human experience and judgement, it does provide a methodical approach to the identification of hazards and evaluation of risks to the system

Cosmic ray modulation in a random anisotropic magnetic field

Inhomogeneities of the interplanetary magnetic field can be divided into small scale and large scale ones as may be required by the character of the problem of cosmic ray (CR) propagation. CR propagation in stochastic magnetic fields is of diffusion character. The main contribution into the scattering of CR particles is made by their interaction with inhomogeneities of the magnetic field H which have characteristic dimensions 1 of the order of Larmor radius R=cp/eH of particle (p is the absolute value of particle momentum, e is particle charge, c is velocity of light). Scattering of particles on such inhomogeneities leads to their diffusion mostly along a magnetic field with characteristic dimensions of variation in space exceeding the mean free path

Study of cosmic ray scintillations from 5-minute data of the scintillations telescope Izmran and world-wide network stations

During cosmic ray propagation in interplanetary space there appear characteristic cosmic-ray intensity scintillations which are due to charged particle scattering on random inhomogeneities of the interplanetary magnetic field. The power spectra of cosmic ray scintillations on the Earth during some intervals from 1977 to 1982 (for quiet periods, for solar flares and Forbush decreases due to power shock waves) have been calculated from five-minute, one and two-hour values of the cosmic-ray intensity measured by the scintillator supertelescope IZMIRAN. The spectra were estimated by the methods of spectral analysis and by autoregressive methods which mutually control each other and make it possible not only to analyze scintillation powers at distinguished frequencies, but also to determine the behavior of spectrum slopes in some frequency ranges

Blue Straggler Stars: The Spectacular Population in M80

Using HST-WFPC2 observations in two ultraviolet (UV) filters (F225W and F336W) of the central region of the high density Galactic Globular cluster (GGC) M80 we have identified 305 Blue Straggler Stars (BSS) which represents the largest and most concentrated population of BSS ever observed in a GGC. We also identify the largest, clean sample of evolved BSS yet found. The high stellar density alone cannot explain the BSS, and we suggest that in M80 we are witnessing a transient dynamical state, during which stellar interactions are delaying the core-collapse process leading to an exceptionally large population of collisional-BSS.Comment: 15 pages, 5 figures, Astrophysical Journal Letters, in pres

Cocaine locomotor activation, sensitization and place preference in six inbred strains of mice

<p>Abstract</p> <p>Background</p> <p>The expanding set of genomics tools available for inbred mouse strains has renewed interest in phenotyping larger sets of strains. The present study aims to explore phenotypic variability among six commonly-used inbred mouse strains to both the rewarding and locomotor stimulating effects of cocaine in a place conditioning task, including several strains or substrains that have not yet been characterized for some or all of these behaviors.</p> <p>Methods</p> <p>C57BL/6J (B6), BALB/cJ (BALB), C3H/HeJ (C3H), DBA/2J (D2), FVB/NJ (FVB) and 129S1/SvImJ (129) mice were tested for conditioned place preference to 20 mg/kg cocaine.</p> <p>Results</p> <p>Place preference was observed in most strains with the exception of D2 and 129. All strains showed a marked increase in locomotor activity in response to cocaine. In BALB mice, however, locomotor activation was context-dependent. Locomotor sensitization to repeated exposure to cocaine was most significant in 129 and D2 mice but was absent in FVB mice.</p> <p>Conclusions</p> <p>Genetic correlations suggest that no significant correlation between conditioned place preference, acute locomotor activation, and locomotor sensitization exists among these strains indicating that separate mechanisms underlie the psychomotor and rewarding effects of cocaine.</p