258 research outputs found
Study and evaluation of electronography Final report
Photographic and electron photographic emulsion efficiencies calculated as function of densit
A spectroscopic study of LMC X-4
The orbital radial velocity semi-amplitude of the binary star system LMC X-4 primary was determined to be 37.9 + or - 2.4 km/s from measurements of the hydrogen absorption lines. The semi-amplitude of the He I and He II absorption lines are consistent with this, namely 44.9 + or - 5.0 and 37.3 + or - 5.3 km/s. The phase and shape of the radial velocity curves of the three ions are consistent with a circular orbit and an ephemeris based upon X-ray measurements of the neutron star, with the exception that the He II absorption line radial velocity curve has detectable shape distortion. Measurements of the He II LAMBOA 4686 emission line velocity are consistent with a phase shifted sine wave of semi-amplitude 535 km/s, a square wave of semi-amplitude 407 km/s, or high order harmonic fits. The spectral type was found to be 08.5 IV-V during X-ray eclipse. Variations to types as early as 07 occur, but not as a function or orbital phase. Absorption line peculiarities were noted on 6 of 58 spectra
On the physical association of the peculiar emission: Line stars HD 122669 and HD 122691
Spectroscopic and photometric observations indicate a physical association between the peculiar early-type emission-line stars HD 122669 and HD 122691. The latter has undergone a drastic change in the strength of its emission lines during the past twenty years. There is some indication that both stars vary with shorter time scales
Physical parameters of the Cen X-3 system
Photographic spectra of Cen X-3 show that the primary star has a spectral type near 06.5 with weak, variable emission at wavelength 4640 and 4686. No orbital motion of the emission or absorption lines is detected; for the latter the upper limit is approximately + or - 50 km/s. Analysis of the available data indicates that the primary is a factor of 2-3 less massive than expected from normal evolutionary models while the X-ray source has a solar mass near 1.5
Photographs of the corona taken during the total eclipse of the Sun on July 9, 1945, at Pine River, Manitoba, Canada
An expedition which went to Pine River, Manitoba, Canada, to observe the total eclipse of the sun on July 9, 1945, is described, and coronal photographs secured during the eclipse are presented
Secretion dynamics of soyasaponins in soybean roots and effects to modify the bacterial composition
Soyasaponins are triterpenoid saponins widely found in legume plants. These compounds have drawn considerable attention because they have various activities beneficial for human health, and their biosynthesis has been actively studied. In our previous study, we found that legume plants including soybean secrete soyasaponins from the roots in hydroponic culture throughout the growth period, but the physiological roles of soyasaponins in the rhizosphere and their fate in soil after exudation have remained unknown. This study demonstrates that soyasaponins are secreted from the roots of field-grown soybean, and soyasaponin Bb is the major soyasaponin detected in the rhizosphere. In vitro analysis of the distribution coefficient suggested that soyasaponin Bb can diffuse over longer distances in the soil in comparison with daidzein, which is a typical isoflavone secreted from soybean roots. The degradation rate of soyasaponin Bb in soil was slightly faster than that of daidzein, whereas no soyasaponin Bb degradation was observed in autoclaved soil, suggesting that microbes utilize soyasaponins in the rhizosphere. Bacterial community composition was clearly influenced by soyasaponin Bb, and potential plant growth-promoting rhizobacteria such as Novosphingobium were significantly enriched in both soyasaponin Bb-treated soil and the soybean rhizosphere. These results strongly suggest that soyasaponin Bb plays an important role in the enrichment of certain microbes in the soybean rhizosphere
Polarization Effects in Reflecting Coronagraphs for White Light Applications in Astronomy
The properties of metal thin films have been largely overlooked in
discussions of the technical limitations and problems that arise in the field
of direct detection of exoplanets. Here, polarization properties and anisotropy
properties of highly reflecting thin metal films are examined within the
context of the requirements for the ultra-low scattered-light system
performance of coronagraphs applied to space and ground-based high-contrast,
white-light astronomy. Wavelength-dependent optical constants for highly
reflecting thin metal films, taken from the literature are used to calculate
the polarization-dependent transmissivity of a typical coronagraph. The effects
of degraded performance on the astronomical science are examined. Suggestions
are made for future work.Comment: 14 Pages, 7 Figures, Accepted to Astrophysical Journa
Results of X-ray and optical monitoring of SCO X-1
Sco X-1 was monitored at optical and X-ray wavelengths from 1970 April 26 to 1970 May 21. The optical observations were made at six observatories around the world and the X-ray observations were made by the Vela satellites. There was a tendency for the object to show greater variability in X-ray when the object is optically bright. A discussion of the intensity histograms is presented for both the optical and X-ray observations. No evidence for optical or X-ray periodicity was detected
The Worst Distortions of Astrometric Instruments and Orthonormal Models for Rectangular Fields of View
The non-orthogonality of algebraic polynomials of field coordinates
traditionally used to model field-dependent corrections to astrometric
measurements, gives rise to subtle adverse effects. In particular, certain
field dependent perturbations in the observational data propagate into the
adjusted coefficients with considerable magnification. We explain how the worst
perturbation, resulting in the largest solution error, can be computed for a
given non-orthogonal distortion model. An algebraic distortion model of full
rank can be converted into a fully orthonormal model based on the Zernike
polynomials for a circular field of view, or a basis of functions constructed
from the original model by a variant of the Gram-Schmidt orthogonalization
process for a rectangular field of view. The relative significance of
orthonormal distortion terms is assessed simply by the numerical values of the
corresponding coefficients. Orthonormal distortion models are easily extendable
when the distribution of residuals indicate the presence of higher order terms.Comment: 1 figure; submitted in PAS
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