Maturation and spawning of marine finfish

Fish utilized for spawning experiments were taken near Port Aransas, Tex., from estuarine and gulf populations of each species. Red drum, Sciaenops ocellata, were taken by hook-and-line and beach seine. Spotted seatrout, Cynoscion nebulosus, and red snapper, Lutjanus campechanus, were collected by hook-and-line. Southern flounder, Paralichthys lethostigma, were taken by hook-and-line and trammel net. Red drum and southern flounder were taken during their fall spawning period and spotted seatrout in the early spring season. Immature red snappers taken in early fall were placed in the spawning tank. The snapper tank was covered with nylon netting to prevent fish from jumping out of the tank. Red drum (750 mm TL), spotted trout (356 mm TL), and southern flounder (males 254 mm TL, females 305 mm TL) were kept as brood fish. Fish were transferred to the laboratory in fiber glass tanks (300-1,900 1) and placed into 1,000-30,000 l fiber glass spawning tanks. Fish were handled carefully to avoid surface abrasions which could result in infections. External parasites were removed with a 25-50 ppm bath of malachite green and Formalin. After this treatment the fish were placed in spawning tanks. Details of the seawater holding facilities are described by Arnold et al. (1976). Photoperiod and temperature data were gathered from U.S. Coast Guard and U.S. Weather Service records for Port Aransas, Tex. By comparing larval collections or adult spawning records of redfish (Simons and Breuer 1962), southern flounder (Stokes 1975), spotted trout (Miles 1950), and red snapper (Mosely 1966), the photoperiods and temperatures for the natural spawning seasons were determined. The laboratory photoperiod and temperature regimes for induced spawning of these four species were based on these meteorological and hydrological records.Marine Scienc

Electrically Conductive Paints for Satellites

A program was conducted to develop and test electrically conductive paint coatings for spacecraft. A wide variety of organic and inorganic coatings were formulated using conductive binders, conductive pigments, and similar approaches. Z-93, IITRI's standard specification inorganic thermal control coating, exhibits good electrical properties and is a very space-stable coating system. Several coatings based on a conductive pigment (antimony-doped tin oxide) in silicone and silicate binders offer considerable promise. Paint systems using commercially available conductive polymers also appear to be of interest, but will require substantial development. Evaluations were made based on electrical conductivity, paint physical properties, and the stability of spectral reflectance in space environment testing

Larval fish in the vicinity of aquaculture intakes

Texas Parks and Wildlife Department has recently proposed that all facilities pumping water from Texas estuaries be fitted with 0.5 mm screening to prevent larval fish mortality at these facilities. Data on larval fish distributions in Texas estuaries is quite limited (Holt et al. 1990). This report presents the results of a pilot study to examine the impact on larval fishes and shrimps of pumping water into mariculture facilities at three sites on the central and southern Texas Coast. The primary objective of this study was to determine the species composition, density and size structure of ichthyoplankton populations in the vicinity of the intake structures of the three mariculture facilities during their spring and fall pumping seasons. A secondary objective was to determine what organisms were actually being pumped through the system.Final report for contract IAC(90-91)111.5Prepared for Texas A&M Sea Grant, Texas General Land OfficeFebruary 1991Marine Scienc

Spectroscopic study of unique line broadening and inversion in low-pressure microwave generated water plasmas

It was demonstrated that low pressure (~0.2 Torr) water vapor plasmas generated in a 10 mm inner diameter quartz tube with an Evenson microwave cavity show at least two features which are not explained by conventional plasma models. First, significant (> 0.25 nm) hydrogen Balmer_ line broadening, of constant width, up to 5 cm from the microwave coupler was recorded. Only hydrogen, and not oxygen, showed significant line broadening. This feature, observed previously in hydrogen-containing mixed gas plasmas generated with high voltage dc and rf discharges was explained by some researchers to result from acceleration of hydrogen ions near the cathode. This explanation cannot apply to the line broadening observed in the (electrodeless) microwave plasmas generated in this work, particularly at distances as great as 5 cm from the microwave coupler. Second, inversion of the line intensities of both the Lyman and Balmer series, again, at distances up to 5 cm from the coupler, were observed. The line inversion suggests the existence of a hitherto unknown source of pumping of the optical power in plasmas. Finally, it is notable that other aspects of the plasma including the OH* rotational temperature and low electron concentrations are quite typical of plasmas of this type.Comment: 27 pages, 7 figure

Correlations at intermediate pTp_T

Correlations among hadrons in jets produced in heavy-ion collisions are discussed in the framework of the recombination model. The basic correlation at the parton level is among the shower partons arising from kinematical constraint. The resultant correlation between hadrons at intermediate $p_T$ is amazingly rich in characteristics.Comment: 10 pages including 12 figures. Talk presented at the MIT Workshop on Correlations and Fluctuations in Relativistic Nuclear Collisions, April 200

Metric tensor as the dynamical variable for variable cell-shape molecular dynamics

We propose a new variable cell-shape molecular dynamics algorithm where the dynamical variables associated with the cell are the six independent dot products between the vectors defining the cell instead of the nine cartesian components of those vectors. Our choice of the metric tensor as the dynamical variable automatically eliminates the cell orientation from the dynamics. Furthermore, choosing for the cell kinetic energy a simple scalar that is quadratic in the time derivatives of the metric tensor, makes the dynamics invariant with respect to the choice of the simulation cell edges. Choosing the densitary character of that scalar allows us to have a dynamics that obeys the virial theorem. We derive the equations of motion for the two conditions of constant external pressure and constant thermodynamic tension. We also show that using the metric as variable is convenient for structural optimization under those two conditions. We use simulations for Ar with Lennard-Jones parameters and for Si with forces and stresses calculated from first-principles of density functional theory to illustrate the applications of the method.Comment: 10 pages + 6 figures, Latex, to be published in Physical Review

Abundance and distribution of larval fishes and shrimps in the Laguna Madre, Texas : a hypersaline lagoon

To Texas Water Development BoardContract nos. IAC (88-89)1636 and (90-91)0751October 1990Tidal inlets connecting the Gulf of Mexico with estuarine waters are widely spaced and relatively narrow along the Texas coast. These inlets provide the sole route for ingress of larvae to the estuary for estuarine-dependent marine species and the egress of juveniles and sub-adults of these species back to the ocean. This study was an investigation of the abundance and distribution of ichthyoplankton of selected fishes and shrimps in an area where the opening and maintenance of a new tidal pass has been proposed in the Laguna Madre, a sub-tropical, hypersaline lagoon along the southern Texas coast. Surface and bottom ichthyoplankton samples were taken bimonthly in four zones in the Laguna Madre in areas which were directly influenced by tidal inlets from the Gulf of Mexico and areas isolated from such connections. Seasonal composition of the ichthyoplankton was similar to that reported from other Gulf of Mexico and southeastern United States estuaries with winter catches dominated by offshore spawners and summer catches dominated by inshore and estuarine spawners. The pelagic larvae of three species of estuarine spawners, bay anchovy (Anchoa mitchilli), spotted seatrout (Cynoscion nebulosus), and black drum (Pogonias cromis), were common throughout the Laguna Madre at salinities up to 50°/00. Pelagic larvae of offshore spawners were abundant only in the area near the tidal inlet and only a few individuals were found dispersed throughout the lagoon. The majority of these species are distributed throughout the Laguna Madre as juveniles but the dispersion or advection of these species to areas not closely associated with tidal inlets occurs at development stages older than the pelagic larval stage. These data suggest that opening and maintaining a tidal inlet in the upper Laguna Madre would increase the opportunity for recruitment of larvae of offshore spawners into an area currently unoccupied by these life-history stages.Marine Scienc

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Teaching/Communication/Extension/Profession,

The soils of Sullivan County

Caption title.At head of title: University of Missouri, Agricultural Experiment Station ... U. S. Department of Agriculture. Bureau of Soils ... Soil survey of Missouri

Control of the humus supply of certain important Missouri soils

TypescriptM.S. University of Missouri 1908The soils of Missouri, with very few exceptions, are deficient in humus, and the continuous cropping (to corn especially) which is practiced in many parts of the state is rapidly depleting what humus there is in the soil. In many parts of the state the crop yields are rapidly decreasing as a result of this, while in other localities it is not as yet evidenced in the crop yields to a perceptible degree, but in either case it demands attention, for it is much easier to maintain a natural humus supply than it is to build one up, and in the case of the lands where it is now effecting the crop yield it must be built up or the land will soon fail to produce a remunerative crop. In order to study the effect of various crop rotations and fertilizer treatments upon the humus content of Missouri soils two lines of experiment were carried out. First, a study of the effect of crop rotation and manures upon the humus and nitrogen content of soils as evidenced in the rotation plats of the Missouri Experiment Station. And second, a study of the needs of organic matter of some of the more important soils of the state by means of the paraffine wire basket method