118,182 research outputs found
NASA-ARC 91.5-cm airborne infrared telescope
A 91.5 cm aperture telescope installed aboard NASA-Lockheed C-141A aircraft for the performance of infrared astronomy is described. A unique feature of the telescope is that its entire structure is supported by a 41 cm spherical air bearing which effectively uncouples it from aircraft angular motion, and with inertial stabilization and star tracking, limits tracking errors to less than 1 arc second in most applications. A general description of the system, a summary of its performance, and a detailed description of an offset tracking mechanism is presented
Shell model description of the 14C dating beta decay with Brown-Rho-scaled NN interactions
We present shell model calculations for the beta-decay of the 14C ground
state to the 14N ground state, treating the states of the A=14 multiplet as two
0p holes in an 16O core. We employ low-momentum nucleon-nucleon (NN)
interactions derived from the realistic Bonn-B potential and find that the
Gamow-Teller matrix element is too large to describe the known lifetime. By
using a modified version of this potential that incorporates the effects of
Brown-Rho scaling medium modifications, we find that the GT matrix element
vanishes for a nuclear density around 85% that of nuclear matter. We find that
the splitting between the (J,T)=(1+,0) and (J,T)=(0+,1) states in 14N is
improved using the medium-modified Bonn-B potential and that the transition
strengths from excited states of 14C to the 14N ground state are compatible
with recent experiments.Comment: 4 pages, 5 figures Updated to include referee comments/suggestion
Family planning success in two cities in Zaire
Both projects described here, Matadi and Kananga, helped health providers in those two cities offer clinical family planning services. But their approaches differed markedly. The family education program in Matadi concentrated on pioneering community-based distribution of contraceptives, with carefully supervised distributors. The Kanaga Project emphasized clinical supervision and pleasing the clients; introduced social marketing with loose supervision of retailers; and provided an information team skilled in face-to-face group meetings, plus a weekly radio program. Four factors common to both projects seemed to contribute to their success: The single-minded dedication of staff members to making family planning work. An uninterrupted supply of affordable contraceptive methods available through outlets at many locations. Enough organizational autonomy to be able to respond to problems as they arose. Such autonomy made project personnel identify more with project goals and feel responsible for achieving project objectives. Regular and supportive supervision of those responsible for service delivery. Both projects emphasized regular contact with clinic personnel - Matadi also included distributors. These contacts bolstered morale by showing that the project administration was closely following service providers'activities and by transmitting to providers the staff's enthusiam for project activities. Supervisory visits included administrative functions such as collecting service statistics and controlling inventory, but these activities were handled in a friendly, nonthreatening manner that encouraged service providers to perform their tasks well. The fourth factor is adequate funding. Both projects had special funding that allowed them to experiment with approaches for increasing contraceptive prevalence. That funding may partly explain their organizational autonomy and may have contributed to the sense of purpose and esprit de corps that developed among project staff. Larger-scale programs in Zaire have operated with significant financial constraints, so it would be unfair to compare them with these more successful projects. Special funding does not guarantee project success but may make it far more likely, conclude the authors.Health Monitoring&Evaluation,Adolescent Health,ICT Policy and Strategies,Early Child and Children's Health,Reproductive Health
A Search for Resonant Structures in the Zodiacal Cloud with COBE DIRBE: The Mars Wake and Jupiter's Trojan Clouds
We searched the COBE DIRBE Sky and Zodi Atlas for a wake of dust trailing
Mars and for Trojan dust near Jupiter's L5 Lagrange point. We compare the DIRBE
images to a model Mars wake based on the empirical model of the Earth's wake as
seen by the DIRBE and place a 3-sigma upper limit on the fractional overdensity
of particles in the Mars wake of 18% of the fractional overdensity trailing the
Earth. We place a 3-sigma upper limit on the effective emitting area of large
(10-100 micron diameter) particles trapped at Jupiter's L5 Lagrange point of 6
x 10^17 cm^2, assuming that these large dust grains are distributed in space
like the Trojan asteroids. We would have detected the Mars wake if the surface
area of dust in the wake scaled simply as the mass of the planet times the
Poynting-Robertson time scale.Comment: Sixteen pages, and figures 1, 2, 3a, 3b, 4, 5, 6, and 7. Accepted for
publication in Icaru
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