INTERACTIVE COMPUTER SIMULATION OF THE SPATIAL PROCESS OF SOIL EROSION

The ability to assess the impacts of changes in the physical environment prior to their occurrence has become possible through the development of SOILCART, an interactive computer program. This program evaluates the potential soil loss of an area in both a temporal and spatial framework. SOILCART has proved its usefulness both as a research and a teaching tool.     

Observations related to the possibility that there are different mechanisms of formation for O-type stars and later type stars

Carbon monoxide observations of neutral matter near W3 provide an excellent example of the formative process for O stars. As in other regions where O stars are forming, the young stars in W3 are located in dense cloud fragments that are at the edge of an extended molecular cloud complex. This peculiar formation site is simply explained in terms of a million year old shock that probably surrounds the expanding H II region IC1805. The contrast between this situation for W3 and what is found in other star-forming regions where only low mass stars occur is emphasized.Paper presented at the conference on Protostars and Planets, held at the Planetary Science Institute, University of Arizona, Tucson, Arizona, between January 3 and 7, 1978.     

SUMMARY OF SEVERAL RECENT CHONDRITE FINDS FROM THE TEXAS PANHANDLE

Eleven recent chondrite finds from the Texas Panhandle have been examined and classified according to mineralogical and petrological criteria: five H's, five L's, and one LL chondrite. Five are distinct from nearby finds, while three remain ambiguous and three are related to previously reported chondrites. In addition, data are provided to classify the Muleshoe, Silverton, and Vigo Park chondrites, all of which were previously undescribed in the literature.     

An estimation of the fluctuations in the extreme limb of the Sun

Detailed computations of synthetic solar limb curves are carried out for the purpose of estimating the effects of inhomogeneities in the solar atmosphere upon the observed limb position. Methods of determining the limb position given a solar limb curve are compared. The method of finding the locus of a fixed intensity level with respect to the average disk-center intensity at a given wavelength seems to be the most tractable definition to use on noise free data. It is found that limb fluctuations due to the solar 5-min p-mode oscillations produce a fluctuation in the limb height of about 6 km (0.008 arc sec) rms. Limb fluctuations due to granulation and chromospheric structure are much smaller. The wavelength dependence of the solar H^? opacity causes the height of the limb to increase by about 35 km between 400 and 850 nm, thus leading to a ‘limb reddening’ at the extreme limb of the Sun.     

STREAM POWER TERMINOLOGY

A standardized nomenclature is presented that clarifies the differences among measures of stream power. It is advocated that the term stream power be used in a conceptual context only. The recommended terminology for the various measures of this general concept is total stream power for the power of an entire reach or stream, crosssectional stream power for power per unit length, mean stream power for power per unit wetted area. and unit stream power for power per unit weight of water.     

Variations in air density,satellite drag coefficient and atmospheric rotation rate from analysis of the orbit of 1966-92D

Variations in air density, the satellite drag coefficient, and the atmospheric rotation rate at 60°S lat and 120–130 km height during the period September 1968–June 1969 have been determined from analysis of the high-eccentricity orbit of the 4th Molyniya 1 upper-stage rocket body, 1966-92D. The results show good correlation between density increases and strong geomagnetic activity, although solar flares of equal geomagnetic index value do not consistently produce density changes of equal magnitude. A 30 per cent semi-annual variation was observed, but there was no indication of the 50 per cent lower thermosphere seasonal-latitudinal variation that was predicted from the CIRA 1972 atmosphere. The satellite drag coefficient was observed to begin decreasing with height at an altitude where the molecular mean free path, λ, was twice the satellite's length. The coefficient decreased to a value approaching 1.0 as the satellite's perigee height fell below the altitude where λ was one-half the length. A mean atmospheric rotation rate of 1.1 ± 0.1 Earth rot/day was obtained for the last 20 days of decay. However, variations were observed with west-to-east wind speeds of ?100 m/sec measured for a local time of 13 hr.     

Temperature effects on the embryo development and hatching of the spiny lobster Sagmariasus verreauxi

Factors affecting the development of the embryos and production of larvae of the spiny lobster Sagmariasus verreauxi were investigated. Mature lobsters were collected from the fishery in New Zealand and held in captivity until they moulted, mated, and extruded eggs. For females, moulting took place in winter (July/August) and mating occurred 58–88 days later in early spring. The ovigerous females were then held at three temperatures and embryo development monitored at approximately weekly intervals. Mean times to hatch were 55, 75, and 130 days at 20°C, 17°C, and 13°C respectively. The total number of larvae that hatched from each female ranged from 0.97 to 1.4 million. The theoretical temperature at which embryo development ceases (a biological zero) for S. verreauxi, of 9.4°C, was calculated from data on the appearance of the median eye, the eyes and the chromatophores, and the time to hatch. An eye index formula was also derived to allow prediction of time to hatch at a range of temperatures using the cumulative difference between the rearing temperature and the biological zero. First instar phyllosomas from embryos reared at 20°C were significantly smaller than those from 17°C and 13°C but there was no significant difference in fitness. This study shows that hatching can be spread over a number of months, without significantly affecting larval quality, simply by manipulating holding temperature.