Microscopes and computers combined for analysis of chromosomes

Scanning machine CHLOE, developed for photographic use, is combined with a digital computer to obtain quantitative and statistically significant data on chromosome shapes, distribution, density, and pairing. CHLOE permits data acquisition about a chromosome complement to be obtained two times faster than by manual pairing

Lose the plot: cost-effective survey of the Peak Range, central Queensland

The Peak Range (22˚ 28’ S; 147˚ 53’ E) is an archipelago of rocky peaks set in grassy basalt rolling-plains, east of Clermont in central Queensland. This report describes the flora and vegetation based on surveys of 26 peaks. The survey recorded all plant species encountered on traverses of distinct habitat zones, which included the ‘matrix’ adjacent to each peak. The method involved effort comparable to a general flora survey but provided sufficient information to also describe floristic association among peaks, broad habitat types, and contrast vegetation on the peaks with the surrounding landscape matrix. The flora of the Peak Range includes at least 507 native vascular plant species, representing 84 plant families. Exotic species are relatively few, with 36 species recorded, but can be quite prominent in some situations. The most abundant exotic plants are the grass Melinis repens and the forb Bidens bipinnata. Plant distribution patterns among peaks suggest three primary groups related to position within the range and geology. The Peak Range makes a substantial contribution to the botanical diversity of its region and harbours several endemic plants among a flora clearly distinct from that of the surrounding terrain. The distinctiveness of the range’s flora is due to two habitat components: dry rainforest patches reliant upon fire protection afforded by cliffs and scree, and; rocky summits and hillsides supporting xeric shrublands. Plants endemic to the Peak Range are mainly associated with the latter of these habitats

Rotationally resolved collisional transfer rates in OH

Fluorescence lidar measurements of the hydroxyl radical require detailed information concerning collision induced processes in order to deduce the radical number density from a lidar return. The Goddard SFC OH lidar currently utilizes a broadband detector which precludes the necessity of fully understanding collisional redistribution of rotational energy within the excited state. Numerous advantages result however from the inclusion of a detector with a bandpass only slightly larger that the Doppler width of a rotational line. This however places more stringent requirements on the spectroscopy. Measurements were accordingly made of rotationally resolved quenching rates for collisions with O2, N2, and H2O. Rotational transfer rates were also measured for the same colliders. Quenching rates were measured using a Nd-YAG pumped Rh6G dye laser doubled into the UV. The OH lifetimes were measured as a function of pressure of quenching gas at total pressures of between 50 and 250 microns. Rotational transfer rates were measured by recording the emission spectrum on an intensified diode array and integrating over 10.000 laser shots

Analysis of the trajectory, loads and heating experienced by a body passing through a supersonic flow field

Analytical methods for determination of trajectories, loads, and heating experienced by spacecraft passing through rocket exhaust fiel

Radar Investigation of Mars, Mercury, and Titan

Radar astronomy is the study of the surfaces and near surfaces of Solar System objects using active transmission of modulated radio waves and the detection of the reflected energy. The scientific goals of such experiments are surprisingly broad and include the study of surface slopes, fault lines, craters, mountain ranges, and other morphological structures. Electrical reflectivities contain information about surface densities and, to some extent, the chemical composition of the surface layers. Radar probes the subsurface layers to depths of the order of 10 wavelengths, providing geological mapping and determinations of the object’s spin state. Radar also allows one to study an object’s atmosphere and ionic layers as well as those of the interplanetary medium. Precise measurements of the time delay to surface elements provide topographic maps and powerful information on planetary motions and tests of gravitational theories such as general relativity. In this paper, we limit our discussion to surface and near-surface probing of Mercury, Mars, and Titan and review the work of the past decade, which includes fundamentally new techniques for Earth-based imaging. The most primitive experiments involve just the measurement of the total echo power from the object. The most sophisticated experiments would produce spatially resolved maps of the reflected power in all four Stokes’ parameters. Historically, the first experiments produced echoes from the Moon during the period shortly after World War II (see e.g. Evans 1962), but the subject did not really develop until the early 1960s when the radio equipment was sufficiently sensitive to detect echoes from Venus and obtain the first Doppler strip "maps" of that planet. The first successful planetary radar systems were the Continuous Wave (CW) radar at the Goldstone facility of the Caltech’s Jet Propulsion Laboratory and the pulse radar at the MIT Lincoln Laboratory. All of the terrestrial planets were successfully studied during the following decade, yielding the spin states of Venus and Mercury, a precise value of the astronomical unit, and a host of totally new discoveries concerning the surfaces of the terrestrial planets and the Moon. This work opened up at least a similar number of new questions. Although the early work was done at resolution scales on the order of the planetary radii, very rapid increases in system sensitivities improved the resolution to the order of 100 km, but always with map ambiguities. Recently, unambiguous resolution of 100 m over nearly the entire surface of Venus has been achieved from the Magellan spacecraft using a side-looking, synthetic aperture radar. Reviews of the work up to the Magellan era can be found in Evans (1962), Muhleman et al (1965), Evans & Hagfors (1968, see chapters written by G Pettengill, T Hagfors, and J Evans), and Ostro (1993). The radar study of Venus from the Magellan spacecraft was a tour de force and is well described in special issues of Science (volume 252, April 12, 1991) and in the Journal of Geophysical Research (volume 97, August 25 and October 25, 1992). Venus will not be considered in this paper even though important polarization work on that planet continues at Arecibo, Goldstone, and the Very Large Array (VLA). In this paper we review the most recent work in Earth-based radar astronomy using new techniques of Earth rotation, super synthesis at the VLA in New Mexico (operated by the National Radio Astronomy Observatory), and the recently developed "long-code" techniques at the Arecibo Observatory in Puerto Rico (operated by Cornell University). [Note: It was recently brought to our attention that the VLA software "doubles" the flux density of their primary calibrators. Consequently, it is necessary to half the radar power and reflectivity numerical values in all of our published radar results from the VLA/Goldstone radar.] The symbiotic relationship in these new developments for recent advances in our understanding of Mercury and Mars is remarkable. VLA imaging provides for the first time, unambiguous images of an entire hemisphere of a planet and the long-code technique makes it possible to map Mars and Mercury using the traditional range-gated Doppler strip mapping procedure [which was, apparently, developed theoretically at the Lincoln Laboratory by Paul Green, based on a citation in Evans (1962)]. Richard Goldstein was the first to obtain range-gated planetary maps of Venus as reported in Carpenter & Goldstein (1963). Such a system was developed earlier for the Moon as reported by Pettengill (1960) and Pettengill & Henry (1962). We first discuss the synthesis mapping technique

Advanced development of Pb-salt semiconductor lasers for the 8.0 to 15.0 micrometer spectral region

The technology was studied for producing Pb-salt diode lasers for the 8-51 micron spectral region suitable for use as local oscillators in a passive Laser Heterodyne Spectrometer (LHS). Consideration was given to long range NASA plans for the utilization of the passive LHS in a space shuttle environment. The general approach was to further develop the method of compositional interdiffusion (CID) recently reported, and used successfully at shorter wavelength. This technology was shown to provide an effective and reproducible method of producing a single-heterostructure (SH) diode of either the heterojunction or single-sided configuration. Performance specifications were exceeded in several devices, with single-ended CW power outputs as high as 0.88 milliwatts in a mode being achieved. The majority of the CID lasers fabricated had CW operating temperatures of over 60K; 30% of them operated CW above the boiling temperature of liquid nitrogen. CW operation above liquid nitrogen temperature was possible for wavelengths as long as 10.3 microns. Operation at 77K is significant with respect to space shuttle operations since its allows considerable simplification of cooling method

Particle-size characteristics of the vertical dust profiles of two contrasting dust events in the Channel Country of western Queensland, Australia

Spatial and temporal variations in vegetation and soil surface conditions of rangelands add a level of complexity to wind erosion processes which is often difficult to model or measure. Butler and colleagues have developed a methodology which combines computer simulation and experimental measurement to analyse how spatial and temporal changes in dust source area emission rates and atmospheric conditions affect vertical dust concentration profiles during wind erosion events in the Queensland Channel Country. This methodology has not, however, taken into account how variations in dust source area particle-size can affect vertical dust concentration profiles. The present paper examines how the particle-size characteristics of dust source soils affect both vertical dust concentration profiles and the vertical distribution of particle-sizes in two contrasting wind erosion events in the Queensland Channel Country. Comparisons are made between computer simulations of these events and the results of field measurements (of vertical dust concentration profiles) and laboratory measurements (of dust particle-size). Computer simulations of the particle-size emissions from the different dust source areas during the two events produce vertical distributions of dust particle-sizes which are similar to the measured dust particle-sizes for these events. These results indicate that erodibility-induced spatial and temporal variations in particle-size emissions of dust source areas have important influences upon: dust fluxes, vertical dust concentration profiles and the vertical distribution of dust particle-sizes within these profile

Protective telescoping shield for solar concentrator

An apparatus is described for use with a solar concentrator such as a parabolic dish which concentrates sunlight onto a small opening of a solar receiver, for protecting the receiver in the event of a system failure that could cause concentrated sunlight to damage the receiver. The protective apparatus includes a structure which can be moved to a stowed position where it does not block sunlight, to a deployed position. In this position, the structure forms a tube which substantially completely surrounds an axis connecting the receiver opening to the center of the concentrator at locations between the receiver and the concentrator

Thermal control characteristics of a diffuse bladed specular base louver system Final report

Diffuse bladed specular base louver system for spacecraft temperature contro