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Articles 901 - 930 of 985
Full-Text Articles in Entire DC Network
An Economic Valuation Of South Dakota Wetlands As A Recreation Resource For Resident Hunters, Craig W. Johnson
An Economic Valuation Of South Dakota Wetlands As A Recreation Resource For Resident Hunters, Craig W. Johnson
Electronic Theses and Dissertations
In spite of efforts to conserve wetlands, intensified agriculture, water projects, and urban development annually diminish the quantity and quality of wetland resources (Weller 1981). Leitch and Danielson (1979) noted that when the discounted value of the returns to drainage exceed drainage costs there is an economic incentive to drain. If present drainage rates continue, Weller (1981) estimated that most wetlands will disappear by the year 2140. Research has only recently focused attention on the need to estimate the public value of wetland benefits and the social costs of drainage (Leitch and Danielson 1979). The disparity between private and social …
Food Selectivity Of Bluegill And Green Sunfish Fry, Aaron Barkoh
Food Selectivity Of Bluegill And Green Sunfish Fry, Aaron Barkoh
Electronic Theses and Dissertations
Four genera of zooplankton and cladoceran egg cases, collected from a municipal sewage lagoon, were made available as food to green sunfish (Lepomis cyanellus) and bluegill (Lepomis macrochirus) fry, to examine their food selectivity. Green sunfish and bluegill fry ranged in size from 8.5-11.0 mm and 8.0-10.5 mm at stocking and were reared for 31 and 30 days, respectively. The gut contents of 1488 green sunfish and 1440 bluegill fry, representing day and night samples were examined. Diet composition was evaluated using the linear food selection index. Both green sunfish and bluegill fry selected for Cvclops vernalis and consistently selected …
Factors Affecting Water Quality And Microinvertebrate Distribution Within A Small Black Hills Stream, Henry G. Drewes
Factors Affecting Water Quality And Microinvertebrate Distribution Within A Small Black Hills Stream, Henry G. Drewes
Electronic Theses and Dissertations
A comparative evaluation of the benthic macroinvertebrate fauna was conducted concurrently with a physiochemical investigation on Slate Creek, Pennington County, South Dakota in the Black Hills. Water quality differences between years and among stations were detected in Slate Creek from both physiochemical and macroinvertebrate evaluations. The primary sources of disturbance to the Slate Creek study site during the sampling period were landscaping activities within the Deerfield Park Resort development and livestock activity. Increased runoff and elevated stream flows in 1982 were responsible for the variation in water quality between years. Water quality differences among stations indicated significantly (P < 0.05) higher turbidity and temperature immediately below the development site in 1981 and 1982. Significantly (P < 0.05) higher fecal coliform bacteria counts were observed at station 5 for both years, resulting from increased livestock activity. Phosphates and nitrates were highest at stations 4 and 5 but were not significantly (P > 0.05) different …
Crop Oil Additives To Herbicides, R Madin, A Lindsay
Crop Oil Additives To Herbicides, R Madin, A Lindsay
Experimental Summaries - Plant Research
Crop oil additives to herbicides - 84LG42.
Umbrella grass (Cyperus eragrostis) control in irrigated pasture - 85HA1.
Stinkwort control - 85NO5, 85PE14.
Ice plant (Mesembryanthem nodiflorum) control in crop and pasture - 83SG20, 83SG21.
Hoegrass, Herbicide, Plant Growth And Soil Activity Of Glyphosate, T Piper
Hoegrass, Herbicide, Plant Growth And Soil Activity Of Glyphosate, T Piper
Experimental Summaries - Plant Research
Hoegrass tolerant ryegrass. Herbicide incorporation. Plant growth one season after herbicide use. Soil activity of glyphosate. Growth of lupins on plots treated with herbicide for each of the two previous seasons - Trials carried out at Geraldton, Wongan Hills and Wickepin measured the amount of pasture produced on plots that had been treated with herbicides while in crop the previous season.
High Valent Chromium (V) And Chromium (Vi) Complexes, Harry Bennett Davis
High Valent Chromium (V) And Chromium (Vi) Complexes, Harry Bennett Davis
Dissertations and Theses
A new preparative route to the only neutral chromium (V) oxide fluoride, chromium oxide trifluoride, has been accomplished by the reaction of xenon difluoride with chromyl fluoride at high temperature. The chromium oxide trifluoride is produced as crystals which are suitable for single crystal studies. In reactions of chromium oxide trifluoride with alkali and alkaline metal fluorides in anhydrous hydrogen fluoride, new chromium(V) oxide fluoride salts were obtained; these salts were not of high purity due to unknown problems. An attempt to prepare chromium oxide tetrafluoride by the reaction of xenon difluoride with chromyl fluoride in anhydrous hydrogen fluoride failed …
Effect Of Temperature On The Association Constants Of Some Divalent Metal Ions With Chloride In Sea Water-Like Solutions, Jose Vinicio Macias Zamora
Effect Of Temperature On The Association Constants Of Some Divalent Metal Ions With Chloride In Sea Water-Like Solutions, Jose Vinicio Macias Zamora
University of the Pacific Theses and Dissertations
Association constants for the formation of lead (II) chloride complexes were studies in aqueous solutions also containing copper (II) and cadmium (II) ions.
The ionic strength was adjusted with sodium perchlorate to resemble that of sea water. The temperature was set at fixed values between 5° and 35° C to determine the effect on the equilibria in these systems. The total metal concentration was less than 10-8 M.
Differential pulse anodic striping voltammetry was used with a conventional three electrode system and a thin-film working electrode of Pt/Hg. Complex formation was followed as a function of the ligand concentration …
Synthesis Of 2-Alkylidene-1,3-Cyclohexanediones, Mary Virginia Manson
Synthesis Of 2-Alkylidene-1,3-Cyclohexanediones, Mary Virginia Manson
Dissertations, Theses, and Masters Projects
No abstract provided.
A Method For Evaluating The Long-Term, Cumulative Impacts Of Tidal Marsh Alterations: The York River System, A Case Study, Andrew W. Zacherle
A Method For Evaluating The Long-Term, Cumulative Impacts Of Tidal Marsh Alterations: The York River System, A Case Study, Andrew W. Zacherle
Dissertations, Theses, and Masters Projects
No abstract provided.
Nanoplankton Dynamics In A Salt Marsh-Mudflat Ecosystem, Helena Maria Galvaeo
Nanoplankton Dynamics In A Salt Marsh-Mudflat Ecosystem, Helena Maria Galvaeo
Dissertations, Theses, and Masters Projects
No abstract provided.
Electron Detachment In Negative Ion-Molecule Collisions, Mohammed Saiful Huq
Electron Detachment In Negative Ion-Molecule Collisions, Mohammed Saiful Huq
Dissertations, Theses, and Masters Projects
Absolute total cross sections for electron detachment, reactive scattering, charge transfer and dissociative charge transfer have been measured for collisions of hydrogen and halogen negative ions with various molecular targets. The reactants investigated involve H('-), D('-), F('-), Cl('-), Br('-) and I('-) ions as projectiles and H(,2), D(,2), HD, N(,2), CO, O(,2), CO(,2), CH(,4) and Cl(,2) molecules as targets. The energy range of these experiments extended from about 1 eV to about 300 eV in the lab.;The threshold behavior of the detachment cross sections for the reactants H('-)(D('-)) + H(,2),D(,2) and HD has been determined. The thresholds for detachment for both …
Soil Improvement With Bauxite Residues, W H. Tacey, S. C. Ward, K. J. Summers, N. J. Barrow
Soil Improvement With Bauxite Residues, W H. Tacey, S. C. Ward, K. J. Summers, N. J. Barrow
Journal of the Department of Agriculture, Western Australia, Series 4
The sandy soils of the Peel-Harvey catchment hold water and nutrients very poorly. The Gavin ridges dry out quickly during rainless periods and this severely limits pasture growth. These ridges and the lower lying Joel and Coolup sands also lose a large proportion of the phosphorus, sulfer and potash fertilisers applied to them. Normally the sands lack clay materials to bind and hold the nutrients so rainfall leaches them out.
The Peel-Harvey Study Group, CSIRO, Alcoa and Murdock University have studied the use of a residue from bauxite mining to help overcome these problems. The treated residue has a texture …
Soil Types And Drainage, Eric Bettenay, N. J. Schofield
Soil Types And Drainage, Eric Bettenay, N. J. Schofield
Journal of the Department of Agriculture, Western Australia, Series 4
At least 90 per cent of the phosphorus entering the Peel-Harvey estuarine system comes from land cleared for agriculture, most of it from the coastal plain. These soils are naturally deficient on phosphorus and sulfur and this is supplied in superphosphate, which contains about 10 per cent phosphorus and 1 percent sulphur.
However, rain leaches some of this applied phosphorus from the land into drains and rivers which flow into the estuary. In 1981, farmers in the Harvey River-Mayfields Drain catchment lost the equivalent of 1,300 tonnes of superphosphate into the estuary. Between them they have in effect spent $120,000 …
Alternative Pasture Species For Deep Sands, D A. Nicholas
Alternative Pasture Species For Deep Sands, D A. Nicholas
Journal of the Department of Agriculture, Western Australia, Series 4
Although the climate of the swan coastal plain between Perth and Bunbury is suitable for growing a range of pasture species, some soil types greatly limit this range.
Pasture species commonly grown in the South-West, such as subteranean clover and annual ryegrass, can only be grown successfully on the better soils of the coastal plain - the loams, yellow sands and Joel sands. On the freely drained, deep, infertile Gavin sands such species rarely persist because of the soil's poor water holding capacity, and its water repellency and its poor ability to retain nutrients.
Alternative Land Uses, D A. Morrison, B. C. Mattinson
Alternative Land Uses, D A. Morrison, B. C. Mattinson
Journal of the Department of Agriculture, Western Australia, Series 4
One aproach to minimise the high nutrient content and associated algal pollution of the Peel-Harvey estuarine system is to reduce phosphorus losses at their source. Farmers can do this by changing land use is such a way thar phosphorus run-off fromthe catchment soils into drainage is prevented or at least reduced.
The department of Agriculture is investigating the economics of alternative uses, particularly substituting forestry with Pinus pinaster or Eucalyptus globulus (Tasmanian blue gum) for present beef and sheep enterprises. P. pinaster is used for logging and E. globulus for pulping.
Research Objectives In Vertebrate Pest Control, A J. Oliver
Research Objectives In Vertebrate Pest Control, A J. Oliver
Journal of the Department of Agriculture, Western Australia, Series 4
The European rabbit, introduced into Australia in 856 by an early settler for hunting, caused massive losses to agricultural production in Western Australia in 1940s and 1950s.
In those years most of the country's recources and efforts allocated to vertebrate pest problems were aimed at controlling this animal.
Research and control measures by Commonwealth and State agencies, including the introduction of myxomatosis, were largely responsible for reducing the rabbit problem to the comparatively minor one it is now.
Today, the Agricultural Protection Board is involved in the control of a much wider range of mammals and birds which cause losses …
Lower Chesapeake Bay Surface Turbidity Variations As Detected From Landsat Images, Michael S. Fedosh
Lower Chesapeake Bay Surface Turbidity Variations As Detected From Landsat Images, Michael S. Fedosh
Dissertations, Theses, and Masters Projects
Landsat images are analyzed to investigate the causes of turbidity variations in lower Chesapeake Bay surface water. Visual analysis and image enhancement are used in association with optical film density data obtained along selected Bay transects. The optical density data of all images, inversely related to surface turbidity, are used to produce residual turbidity profiles showing turbidity above and below average conditions. meteorological conditions have Images with similar tidal or their residual optical density data averaged to identify probable causes of above average turbidity levels. Freshwater discharge does not directly contribute suspended sediment to Chesapeake Bay, except from the Potomac …
The Response Of Benthic Respiration To Nutrient Levels, Laurence E. Gadbois
The Response Of Benthic Respiration To Nutrient Levels, Laurence E. Gadbois
Dissertations, Theses, and Masters Projects
No abstract provided.
A New Method For The Quantitative Determination Of Radon-222 In Natural Waters, Charles Whitlow
A New Method For The Quantitative Determination Of Radon-222 In Natural Waters, Charles Whitlow
Honors Theses
Several studies in the past have shown radon to be present in many natural waters including mineral springs, hot springs, rivers, lakes, and rainwater. A compilation of tables of radon concentration in mineral and hot springs all over the world was published by Kuroda in 1953. Most of this radon comes from radium and uranium minerals which the springs flow over. The radon concentration in lakes is from two major souces [sic]. One source is dissolved radium and the other is the inflow of high radon concentration groundwaters [sic].
Totally Empirical Wavefunctions From X-Ray Diffraction Data, Martin Jeffry Goldberg
Totally Empirical Wavefunctions From X-Ray Diffraction Data, Martin Jeffry Goldberg
Dissertations, Theses, and Capstone Projects
The interpretation of coherent x-ray diffraction experiments by a quantum model is described. Adjusting the coefficients of an LCAO expansion to best fit measured Bragg intensities results in a totally empirical quantum wavefunction. The quantum model is compared to a multipole expansion. The constraints imposed by quantum mechanics are examined, and several methods of satisfying these constraints while best fitting a wavefunction to measured Bragg intensities are detailed. Application is made to beryllium metal, with a resultant fit R(,1) = .00249. Similar applications to graphite and diamond are outlined. The formalism is extended to explicitly include solid-state effects, and this …
A Theoretical F Region Study Of Ion Compositional And Temperature Variations In Response To Magnetospheric Storm Inputs, Jan Josef Sojka, Robert W. Schunk
A Theoretical F Region Study Of Ion Compositional And Temperature Variations In Response To Magnetospheric Storm Inputs, Jan Josef Sojka, Robert W. Schunk
All Physics Faculty Publications
The response of the polar ionosphere to magnetospheric storm inputs was modeled. During the “storm,” the spatial extent of the auroral oval, the intensity of the precipitating auroral electron energy flux, and the plasma convection pattern were varied with time. The convection pattern changed from a symmetric two-cell pattern with a 20-kV cross-tail potential to an asymmetric two-cell pattern with enhanced plasma flow in the dusk sector and a total cross-tail potential of 90 kV. During the storm there were significant changes in the ion temperature, ion composition, and molecular/atomic ion transition height. The storm time asymmetric convection pattern produced …
Nighttime Thermospheric Winds Over Sondre Stromfjord, Greenland, J W. Meriwether Jr., P Shih, T L. Killeen, Vincent B. Wickwar, R G. Roble
Nighttime Thermospheric Winds Over Sondre Stromfjord, Greenland, J W. Meriwether Jr., P Shih, T L. Killeen, Vincent B. Wickwar, R G. Roble
All Physics Faculty Publications
Observations of nighttime thermospheric neutral winds made at Sondre Stromfjord, Greenland, with optical and radar instrumentation, showed an occasional abatement in the equatorward meridional wind at a magnetic local time corresponding to the nighttime division between the evening and morning convection cells. This abatement appeared primarily in the poleward observations. In contrast, however, the characteristic midnight “surge” was usually seen in the equatorward set of observations. The apparent acceleration of about 250 m/s or greater within 4.6° latitude we attribute, in part, to a merging of neutral jet streams generated by polar cap ion drag adjacent to the auroral zone …
Ionospheric Currents And F-Region Plasma Boundaries Near The Dayside Cusp, S Vennerstrom, E Friis-Christensen, T S. Jorgensen, C. E. Rasmussen, C R. Clauer, Vincent B. Wickwar
Ionospheric Currents And F-Region Plasma Boundaries Near The Dayside Cusp, S Vennerstrom, E Friis-Christensen, T S. Jorgensen, C. E. Rasmussen, C R. Clauer, Vincent B. Wickwar
All Physics Faculty Publications
Observational evidence of the location of a dayside high‐latitude ionospheric current (DPY current) with respect to the different regimes of the high‐latitude magnetosphere is obtained by analyzing data from the magnetometer chain along the west coast of Greenland in conjunction with simultaneous measurements from the newly established incoherent‐scatter radar facility at Sondre Stromfjord. The latitudinal location of the DPY current is compared with the location of the maximum F‐region electron temperature and with the location of the plasma convection reversal from sunward to antisunward. The maximum in the F‐region electron temperature roughly coincides with the velocity reversal boundary, while the …
Dayside Red Auroras At Very High Latitudes: The Importance Of Thermal Excitation, Vincent B. Wickwar, W Kofman
Dayside Red Auroras At Very High Latitudes: The Importance Of Thermal Excitation, Vincent B. Wickwar, W Kofman
All Physics Faculty Publications
Extensive radar observations have been made from Sondrestrom of the F region in the daytime sector between 70 and 79° Λ. Regions of enhanced electron temperature and electron density are found in close association with the velocity reversal in the morning and afternoon convection cells. From the radar measurements, calculations are made of the contributions to the atomic oxygen emission at 6300A from dissociative recombination and thermal excitation. The latter mechanism, in particular, in the enhancement regions gives rise to intensities that are comparable to those observed at very high latitudes during the past decade.
Observations Of Interplanetary Magnetic Field And Of Ionospheric Plasma Convection In The Vicinity Of The Dayside Polar Cleft, C R. Clauer, P M. Banks, A Q. Smith, T S. Jorgensen, E Friis-Christensen, S Vennerstrom, Vincent B. Wickwar
Observations Of Interplanetary Magnetic Field And Of Ionospheric Plasma Convection In The Vicinity Of The Dayside Polar Cleft, C R. Clauer, P M. Banks, A Q. Smith, T S. Jorgensen, E Friis-Christensen, S Vennerstrom, Vincent B. Wickwar
All Physics Faculty Publications
Dayside ionospheric convection at high latitudes has been examined during a series of experiments using the Sondrestrom radar together with ancillary observations of the interplanetary magnetic field (IMF) by the IMP‐8 spacecraft. The radar experiments obtained a latitude coverage of 67.6° Λ to 81.30° Λ and a temporal resolution of between 14 to 25 minutes. A total of 17 rotations through the dayside cleft region during April, June and July, 1983 have been examined. The observations show two convection cells with sunward flow at lower latitudes and antisunward flow at higher latitudes. The flow commonly rotates through a 180° angle …
The Development And Testing Of Soil Wetting Agents, Douglas Alexander Mcghie
The Development And Testing Of Soil Wetting Agents, Douglas Alexander Mcghie
Conference papers and presentations
Water repellent (non wetting) soils in Western Australia affect pasture and crop establish 7cent and growth, the erosion of particular land classes, and water use and turf health in urban areas. Experimental materials were synthesised to give a range of properties, some of which should optimise the performance as soil wetting agents. The soil wetting and rewetting properties of the experimental and many commerically available wetting agents were evaluated on a coarse, water repellent Bassendean sand using plastic ring infiltrometers. A rainfall simulator was used to study effective rates of the various materials for improving the penetration of rainfall into …
Probability Densities And The Random Variable Transformation Theorem, John D. Ramshaw
Probability Densities And The Random Variable Transformation Theorem, John D. Ramshaw
Physics Faculty Publications and Presentations
D. T. Gillespie has recently derived and discussed a random variable transformation (RVT) theorem relating the joint probability densities of functionally dependent sets of random variables.....
It is hoped that the present discussion will help to disseminate this basic relation among a wider circle of nonspecialists.
Cenozoic Calcareous Nannofossils From Deep Sea Drilling Project Leg 77: Biostratigraphy And Delineation Of Hiatuses, Thomas H. Lang, David K. Watkins
Cenozoic Calcareous Nannofossils From Deep Sea Drilling Project Leg 77: Biostratigraphy And Delineation Of Hiatuses, Thomas H. Lang, David K. Watkins
Department of Earth and Atmospheric Sciences: Faculty Publications
Three of the six Deep Sea Drilling Project (DSDP) Leg 77 sites drilled in the western approaches to the Straits of Florida yielded thick sequences of Cenozoic sediment rich in calcareous nannofossils. Hiatuses are prominent in each of these continuously cored intervals. A prominent upper Oligocene hiatus, observed at each of these three sites, can be correlated to a large-scale "global" regression event. Other disconformable horizons present in the study area cannot be positively related to sealevel fluctuations and may be caused by a number of factors including local tectonic activity. Paleogene sections are generally marked by thick accumulations within …
Paleontological Synthesis, Leg 77, David K. Watkins, Charles L. Mcnulty
Paleontological Synthesis, Leg 77, David K. Watkins, Charles L. Mcnulty
Department of Earth and Atmospheric Sciences: Faculty Publications
Biostratigraphic age assignment and paleoecological analysis of the sedimentary material recovered on Deep Sea Drilling Project Leg 77 provide a temporal and paleoenvironmental framework for the reconstruction of the Cretaceous and Cenozoic geologic history of the deep southeastern Gulf of Mexico. Planktonic foraminiferal and calcareous nannofossil biostratigraphy, in conjunction with sedimentologic evidence, indicates the sporadic nature of sedimentation during the Türonian through Holocene throughout the study area. This trend is especially well developed within the Upper Cretaceous, which is largely represented only by a thin, condensed section at a single site. The Cenozoic is somewhat better represented, although the thin, …
Miocene Burrows Of Extinct Bear Dogs: Indication Of Early Denning Behavior Of Large Mammalian Carnivores, Robert M. Hunt Jr., Xue Xiang-Xu, Joshua Kaufman
Miocene Burrows Of Extinct Bear Dogs: Indication Of Early Denning Behavior Of Large Mammalian Carnivores, Robert M. Hunt Jr., Xue Xiang-Xu, Joshua Kaufman
Department of Earth and Atmospheric Sciences: Faculty Publications
Partial skeletons of four species of extinct carnivores have been found in their dens excavated in the floodplain of an early Miocene ephemeral braided stream at Agate Fossil Beds National Monument, Nebraska. Bear dogs (Carnivora: Amphicyonidae) were the principal occupants; their den dimensions and body size are similar to those of living wolves and hyenas. Discovery of this predator community extends the record of denning behavior of large mammalian carnivores to the early Miocene, 20 million years ago.