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Campbell, D. B.

Publications and source records attributed to Campbell, D. B..

81 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Pulsar fluctuation spectra and the generalized drifting-subpulse phenomenon. II

Pulsar observations at meter wavelengths have been analyzed to investigate pulse-to-pulse variations and to identify regions of the pulse profile which display distinct statistical properties. Fluctuation spectra of eight recently discovered pulsars are presented along with a description of the drifting-subpulse phenomenon in several objects with quasiperiodic responses in their fluctuation spectra. A quantitative analysis of the drifting-subpulse phenomenon in PSR 0031-07 and PSR 0809+74 is given which emphasizes the broad-band nature of the phenomenon. A summary of the memory exhibited by pulsars with time scales of about 50 periods is given.

Backer, D. C.↗
NASA NTRS1974

Individual pulse polarization properties of three pulsars

Both average and individual pulse polarization measurements at 430 MHz are presented for three pulsars: PSR 0823 + 26, PSR 0834 + 06, and PSR 2303 + 30. In each case, the average Stokes parameter waveformes are found to depend on the individual pulse polarization properties in a complicated manner. The average waveforms are in general depolarized by pulse-to-pulse fluctuations in polarization state at a given longitude. Two of the three objects exhibit variations of both linear and circular polarization which are associated with quasi-periodic subpulse modulation phenomena in a manner similar to that reported for linear polarization in PSR 0809 + 74 by Taylor et al. (1971.).

Rankin, J. M.↗
NASA NTRS1973

A program to reduce coronary heart disease risk by altering job stresses

This study reports the design, implementation, and evaluation of a program attempting to reduce job stress by improving person-environment fit with respect to job aspects such as work load, responsibility, and interpersonal relationships. In order to assess the effects of the program, measures of both stress and strain were collected at three points in time--just prior to the program, immediately after the program, and three months after completion of the program. Measures of strain included systolic and diastolic blood pressure, determinations of glucose, cholesterol, and uric acid in the plasma, job satisfaction, and job related self-esteem. The findings were interpreted in light of both program incidents within specific experimental groups and general aspects of the program common to the experimental groups. Additional analyses indicated that both good person-environment fit with respect to participation predicts to good fit with respect to other job aspects over a three month interval and that stress causes strain, rather than the reverse.

Campbell, D. B.↗
NASA NTRS1972

Mercury's perihelion advance - Determination by radar.

Measurement of echo delays of radar signals transmitted from earth to Mercury, yielding an accurate value for the advance of the latter's perihelion position. Given that the sun's gravitational quadrupole moment is negligible, the result in terms of the Eddington-Robertson parameters is (2 + 2 gamma-beta)/3 approximately equal to 1.005 plus or minus 0.007, where gamma = beta = 1 in general relativity, and where 0.007 represents the statistical standard error. Inclusion of the probable contribution of systematic errors raises the uncertainty to about 0.02.

Shapiro, I. I.↗
NASA NTRS1972

Venus - Topography revealed by radar data.

Surface height variations over the entire equatorial region on Venus have been estimated from extended series of measurements of interplanetary radar echo delays. Most notable is a mountainous section of about 3-kilometer peak height located at a longitude of 100 degrees (International Astronomical Union coordinate system). The eastern edge has an average inclination of about 0.5 degrees, which is unusually steep for a large-scale slope on Venus. The resolution of the radar measurements along the surface of Venus varied between about 200 and 400 kilometers with a repeatability in altitude determination generally between 200 and 500 meters. The mean equatorial radius was found to be 6050.0 plus or minus 0.5 kilometers.

Campbell, D. B.↗