3,602 research outputs found
Study of flight management requirements during SST low visibility approach and landing operations. Volume 2 - Delineation of potential problems in supporting the performance of flight management tasks
Potential flight management problems during low visibility landing of supersonic transport
Study of flight management requirements during SST low visibility approach and landing operations Final summary report
Flight management operational problems and task requirements for low visibility approach and landing of supersonic transport
Study of flight management requirements during SST low visibility approach and landing operations. Volume 1 - Definition of baseline SST landing system
Baseline instrument landing system for low visibility approach and landing of supersonic transport
Molecular Mapping of a Male-Sterile Gene in Soybean
A newly identified genie male-sterile mutant in soybean [Glycine max (L.) Merr.] has high seed set under natural field conditions and is potentially useful in breeding programs. Meiosis is normal in the mutant line. Sterility in this mutant is caused by failure of cailose dissolution at the tetrad stage, which results in microspore abortion; however, little is known about the male-sterile gene at the molecular level. The objective of this study was to identify molecular markers linked with the male-sterile gene (ms) and to place the ms gene onto the soybean molecular genetic map. An F2 population of 107 individuals was constructed from a cross between the mutant msMOS (ms ms) and the cultivar Minsoy (Ms Ms). Two hundred seventy markers, including 219 RFLP and 51 SSRs, were evaluated. Of these, 102 RFLP probes and 31 SSR markers detected polymorphisms between the parents. The F2 population was screened for segregation of these polymorphic molecular markers. Analyses revealed that the male-sterile locus, designated ‘ms’, was located on linkage group D1b of the USDA/ISU soybean molecular genetic map. The availability of linked DNA markers will facilitate the genetic analysis of this male-sterility gene in relation to soybean breeding programs, and will be a starting point for the isolation of the ms gene by map-based cloning
Fr1 (root fluorescence) locus is located in a segregation distortion region on linkage group K of soybean genetic map
We report the use of bulked segregant SSR analysis for rapid identification of DNA markers linked to the Fr1 locus in soybean. Pooled DNA extracts from 10 homozygous Fr1 Fr1 and 10 fr1 fr1 F2 plants, derived from a msMOS x Minsoy cross, were analyzed using 65 SSR markers. Five SSRs produced repeatable polymorphisms between paired bulks. Linkage with the Fr1 locus was tested using these five SSR primers and DNA from individual plants of each bulk. DNA polymorphisms generated by these five primers were linked to the Fr1 locus. Linkage of SSR loci with the Fr1locus was verified by using an F2 population segregating for Fr1. The five SSR markers and Fr1 are on linkage group K of the USDA ARS/ISU molecular genetic map. The markers flanking Fr1 are Satt337 (11.0 cM) and Satt044 (0.6 cM). Fr1 previously was mapped on linkage group 12 of the classical genetic map. Thus classical genetic linkage group 12 has been correlated to linkage group K of the molecular genetic map. Six SSR markers were chosen on linkage group K to test the segregation ratio. All six SSRs tested were skewed toward the Minsoy genotype, one chi-square value was statistically significant. This suggested that a gametophyte factor may lie in the region close to Fr1 and most likely close to Satt046
Protective coatings for chromium alloys Final summary report, 31 May 1965 - 30 Jun. 1966
Protective coatings for chromium-5 tungsten allo
Locating Boosted Kerr and Schwarzschild Apparent Horizons
We describe a finite-difference method for locating apparent horizons and
illustrate its capabilities on boosted Kerr and Schwarzschild black holes. Our
model spacetime is given by the Kerr-Schild metric. We apply a Lorentz boost to
this spacetime metric and then carry out a 3+1 decomposition. The result is a
slicing of Kerr/Schwarzschild in which the black hole is propagated and Lorentz
contracted. We show that our method can locate distorted apparent horizons
efficiently and accurately.Comment: Submitted to Physical Review D. 12 pages and 22 figure
Analysis of ``Gauge Modes'' in Linearized Relativity
By writing the complete set of (ADM) equations for linearized waves,
we are able to demonstrate the properties of the initial data and of the
evolution of a wave problem set by Alcubierre and Schutz. We show that the
gauge modes and constraint error modes arise in a straightforward way in the
analysis, and are of a form which will be controlled in any well specified
convergent computational discretization of the differential equations.Comment: 11pages LaTe
Long term study of the seismic environment at LIGO
The LIGO experiment aims to detect and study gravitational waves using ground
based laser interferometry. A critical factor to the performance of the
interferometers, and a major consideration in the design of possible future
upgrades, is isolation of the interferometer optics from seismic noise. We
present the results of a detailed program of measurements of the seismic
environment surrounding the LIGO interferometers. We describe the experimental
configuration used to collect the data, which was acquired over a 613 day
period. The measurements focused on the frequency range 0.1-10 Hz, in which the
secondary microseismic peak and noise due to human activity in the vicinity of
the detectors was found to be particularly critical to interferometer
performance. We compare the statistical distribution of the data sets from the
two interferometer sites, construct amplitude spectral densities of seismic
noise amplitude fluctuations with periods of up to 3 months, and analyze the
data for any long term trends in the amplitude of seismic noise in this
critical frequency range.Comment: To be published in Classical and Quantum Gravity. 24 pages, 15
figure
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