6,725 research outputs found

    Productivity of Florida Springs: final report to Biology Branch, Office of Naval Research progress from December 31, 1955 to May 31, 1956

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    CONTENTS: Factors that control species numbers in Silver Springs, by James L. Yount. Study of the biomass of parasites in the stumpknockers, by Wanda Hunter. Macrophytic communities in Florida inland waters, by Delle N. Swindale. Comment in retrospect, by Howard T. Odum. (15pp.

    Phase separation on a hyperbolic lattice

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    We report a preliminary numerical study by kinetic Monte Carlo simulation of the dynamics of phase separation following a quench from high to low temperature in a system with a single, conserved, scalar order parameter (a kinetic Ising ferromagnet) confined to a hyperbolic lattice. The results are compared with simulations of the same system on two different, Euclidean lattices, in which cases we observe power-law domain growth with an exponent near the theoretically known value of 1/3. For the hyperbolic lattice we observe much slower domain growth, consistent to within our current accuracy with power-law growth with a much smaller exponent near 0.13. The paper also includes a brief introduction to non-Euclidean lattices and their mapping to the Euclidean plane.Comment: Computer Simulation Studies in Condensed Matter Physics 26 (CSP13), Edited by D.P. Landau, S.P. Lewis, H.-B. Schuttle

    Clinostomum marginatum metacercaria: Incidence in Smallmouth Bass from a North Arkansas Stream and in vitro Oxygen Consumption Studies

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    Small mouth bass (Micropterus dolomieui) captured from Crooked Creek (Marion Co., Arkansas) in the summers of 1977 and 1987 were found to have a high incidence of infection with the metacercaria of Clinostomum marginatum (yellow grub). Of 41 fish collected in 1977, 32 (78%) were found infected with metacercariae with some fish containing large numbers of parasites. The number of larvae per fish ranged from 1 to 184, with an average of 23.2 ± 38 per smallmouth. Eighty-six percent of the bass collected in 1987 were found positive for C. marginatum. The number of metacercariae per fish ranged from 1 to 227 with an average of 32.7 ± 54 per fish. Fish from both collection groups ranged in size from 12 to 34 cm. No significant correlation could be found between the number of metacercariae per fish and the length of the host. Using metacercariae removed from host tissue, the effect on oxygen consumption by glucose, serotonin and insulin, singularly or in combination, was measured by manometric methods. Glucose alone did not stimulate oxygen utilization, serotonin alone and with glucose was stimulatory, and insulin with glucose also increased oxygen consumption

    What You Should Know About Brucellosis.

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    Productivity of Florida Springs: Second annual report to Biology Branch, Office of Naval Research progress from January 1 to December 31, 1954

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    Production measurements at different times of the year indicate a linear relationship of light intensity and overall production at about 8% of the visible light energy reaching plant level. Measurements of a coral reef at Eniwetok indicate 6%. Further evidence of breeding at all seasons but with a quantitative pulse in the seasons of maximum light indicates that the seasonal fluctuation in primary production is routed through reproduction rather than through major changes in populations. The succession of plants and anmals of the aufwuchs has been shown with glass slides and counts from Sagittaria blades. Losss of oxygen bubbles during the day and emergence of aquatic insects at night have been measured with funnels. Bell jar measurements are reported for bacterial metabolism on mud surfaces. pH determined CO2 uptake agrees with titration determinations. A few rough estimates of herbivore production have been made from caged snails, aufwuchs succession, and fish tagging. Nitrate uptake a night by aufwuchs communities has been confirmed in a circulating microcosm experiment as well as in bell jars in the springs. Distributions of oxygen and organisms have been used to criticize the saprobe stream classification system. Theoretical consideration of maximum photosynthetic rates in teh literature data indicates logarithmic rate variation inversely with organismal size just as for respiratory metabolism. Extreme pyramid shapes are thus shown for communities in which organismal size decreases up the food chain and for other communities with the same energy influx but with organismal size increasing up the food chain. Literature data is used to further demonstrate the validity of the optimum efficiency-maximum power principle for photosynthesis. Work on plants by Dr. Delle Natelson indicates essential stability of aquatic plant communities after 3 years and about 10-20% reproducibility in previous biomass estimates by Davis. Work on an animal picture of the fishery characteristics by Caldwell, Barry, and Odum is half completed. The study of aquatic insects in relationship to spring gradients by W.C. Sloan has been completed an an M.S. thesis. J. Yount has begun a study of affect of total productivity on community composition using aufwuchs organisms on glass slides placed in different current and light conditions in Silver Springs. (49pp.

    Chromospheric Activity of HAT-P-11: an Unusually Active Planet-Hosting K Star

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    Kepler photometry of the hot Neptune host star HAT-P-11 suggests that its spot latitude distribution is comparable to the Sun's near solar maximum. We search for evidence of an activity cycle in the CaII H & K chromospheric emission SS-index with archival Keck/HIRES spectra and observations from the echelle spectrograph on the ARC 3.5 m Telescope at APO. The chromospheric emission of HAT-P-11 is consistent with a 10\gtrsim 10 year activity cycle, which plateaued near maximum during the Kepler mission. In the cycle that we observed, the star seemed to spend more time near active maximum than minimum. We compare the logRHK\log R^\prime_{HK} normalized chromospheric emission index of HAT-P-11 with other stars. HAT-P-11 has unusually strong chromospheric emission compared to planet-hosting stars of similar effective temperature and rotation period, perhaps due to tides raised by its planet.Comment: 16 pages, 8 figures; accepted to the Astrophysical Journa

    Iron mineralogy of a Hawaiian palagonitic soil with Mars-like spectral and magnetic properties

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    Visible and near-IR spectral data for some palagonitic soils from Mauna Kea, Hawaii, are similar to corresponding spectral data for Mars. It is important to understand the composition, distribution, and mineralogy of the ferric-bearing phases for the best spectral analogues because the correspondence in spectral properties implies that the nature of their ferric-bearing phases may be similar to those on Mars. In order to constrain interpretations of the Martian data, a variety of palagonitic soils should be studied in order to establish to what extent differences in their spectral data correspond to differences in the mineralogy of their ferric-bearing phases. Spectral (350-2100 nm), Mossbauer, magnetic, and some compositional data for one of a suite of Hawaiian palagonitic soils are presented. The soil (HWMK1) was collected below the biologically active zone from the sides of a gully cut at 9000 ft elevation on Mauna Kea. The soil was wet sieved with freon into seven size fractions less than 1 mm

    Development of a unique polyurethane primer/topcoat

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    USBI Company, a Division of Pratt & Whitney Government Engines and Space Propulsion, is involved in corrosion and environmental research and development activities both at their headquarters in Huntsville, Alabama and their Florida Operations at Kennedy Space Center, Florida. The programs involve the development of environmentally compatible materials that improve the corrosion protection of expensive Solid Rocket Boosters (SRB) that are part of the Space Shuttle systems developed and managed by Marshall Space Flight Center in Huntsville, Alabama. Coatings For Industry, a paint manufacturer in Souderton, PA helped formulate and produce the first lot of BOOSTERCOAT paint. High strength aluminum aerospace flight hardware exposed to harsh seacoast environments and seawater immersion presently uses high volatile organic compound (VOC) chromated and lead bearing primers and epoxy topcoats for corrosion protection. Epoxy paint tends to be brittle and has relatively low ultraviolet (UV) exposure resistance. A unique, environmentally compatible, non-leaded/non-chromated, low VOC polyurethane single coat (primer/topcoat) trade named BOOSTERCOAT has been developed for excellent corrosion protection, flexibility, adhesion, chemical and solvent resistance properties. This report will discuss the development of BOOSTERCOAT and the potential opportunities for commercial use in the energy, transportation, chemical, maritime, structural fields
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