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Articles 74101 - 74130 of 78684
Full-Text Articles in Entire DC Network
Particle Simulation Of Biological Sorting On A Supercomputer, Donald Greenspan
Particle Simulation Of Biological Sorting On A Supercomputer, Donald Greenspan
Mathematics Technical Papers - Archive
Cell sorting, or, self reorganization, is modelled by means of particles which obey classical molecular dynamical equations. A system of N second order, nonlinear, ordinary differential equations results when the number of particles is N. Applications and examples are described and discussed, with N > 1000, for both double layer and triple layer self reorganization.
The Effect Of Grass Carp Introduction On Aquatic Vegetation And Existing Fish Populations In Two Small Prairie Lakes, David L. Bauer
The Effect Of Grass Carp Introduction On Aquatic Vegetation And Existing Fish Populations In Two Small Prairie Lakes, David L. Bauer
Electronic Theses and Dissertations
Within two years after triploid grass carp introduction in 2.3 hectare Prior Lake in South Dakota, aquatic vegetation coverage and height in the water column were significantly lower (P<0.005). During the same two year period, triploid grass carp did not significantly reduce aquatic vegetation coverage or height in the water column in 11.4 hectare East Lake Eureka, also in South Dakota. Stocking densities were 49 fish/hectare and 61 fish/hectare (229 mm mean total length) in Prior Lake and East Lake Eureka, respectively. The biomass of prey fish in East Lake Eureka in 1986 was quite high with 88.3, 85.3 and 17.3 kg/hectare for black bullhead (Ictalurus melas), yellow perch (Perea flavescens), and bluegill (Lepomis macrochirus), respectively. The biomass of northern pike (Esox lucius) was also high at 13.8 kg/hectare. A Proportional Stock Density (PSD) of 11 and Relative Weight (WK) of 117 indicated a relatively healthy bluegill population in East Lake Eureka. However, the PSD value for black bullheads was lower (8) while their condition was relatively good (K=l.58). The yellow perch population appeared to be over-populated in East Lake Eureka with a PSD of only 5 and a relatively low condition factor (K=l.14). The northern pike population in East Lake Eureka had a PSD value of 53, but a slightly low Wr of 94. Available prey/predator ratio indicated that there was an excess of prey fish for most size classes of predators. Because no significant vegetation reduction occurred in East Lake Eureka, no changes in existing fish populations could be attributed to grass carp introduction or aquatic vegetation reduction. Data gathered on existing fish populations in East Lake Eureka will serve as a pre-treatment data set to be compared to future conditions if aquatic vegetation is reduced. Fish sampling in Prior Lake was greatly reduced due to a winterkill which occurred in the late winter of 1986. Bluegill and largemouth bass (Micropterus salmoides) were the most abundant fish species found in Prior Lake in 1987. Bluegill appeared to be overpopulated as their PSD value was 1; a high Wr of 109 may have indicated improved conditions immediately following the winterkill. Results for the largemouth bass in Prior Lake were similar with a low PSD (7) and a high w~ (112). Winterkill (Prior Lake) and lack of aquatic vegetation control by grass carp (East Lake Eureka) prohibited making conclusions about the effect of grass carp introduction on the existing fish populations in the two lakes. Further research needs to be conducted in South Dakota to determine appropriate grass carp stocking rates for South Dakota waters, and to evaluate what effect grass carp introduction and aquatic vegetation reduction has on existing fish populations.
Growth, Survival, And Vulnerability To Predation Of Stocked Walleye (Stizostedion Vitreum) Fingerlings, James D. Wolters
Growth, Survival, And Vulnerability To Predation Of Stocked Walleye (Stizostedion Vitreum) Fingerlings, James D. Wolters
Electronic Theses and Dissertations
In laboratory tanks, largemouth bass (Micropterus salmoides) and northern pike (Esox Lucius consumed fathead minnows (Pimephales promelas) 2.6 times more frequently than walleye (Stizostedion vitreum) and 5.7 times more than lepomids. Prey were more vulnerable in circular than rectangular tanks. In field studies, walleye fingerlings averaging 35 mm and 53 mm (mean total length) were stocked in two ponds (3- and 7- hectares) respectively: both contained largemouth bass, northern pike, yellow perch (Perca flavescenes), green sunfish (Lepomis cyanellus), and fathead minnows. Aquatic insects dominated the diet of largemouth bass for 3 days after walleye were stocked, indicating that walleye fingerlings …
A Mass Mortality Of Fishes In Lake Titicaca (Peru-Bolivia) Associated With The Protozoan Parasite Ichthyophthirius Multifiliis, Wayne A. Wurtsbaugh, R. Alfaro
A Mass Mortality Of Fishes In Lake Titicaca (Peru-Bolivia) Associated With The Protozoan Parasite Ichthyophthirius Multifiliis, Wayne A. Wurtsbaugh, R. Alfaro
Watershed Sciences Faculty Publications
In December 1981 , an epizootic of the protozoan parasite Ichthyophthirius multifiliis killed an estimated 18 million killifish Orestias spp. in Lake Titicaca, a high-altitude tropical system. Of the dead fish collected, 93% were adult O. agassii, a commercially important species that is abundant in the littoral zone. Juvenile Orestias spp., pelagic species, and some other littoral zone fis hes were slightly affected. lchthyophthirius multifiliis was probably introduced with exotic fishes brought to Lake Titicaca in the 1940s and 1950s.
Conservation Of Least Terns And Piping Plovers Along The Missouri River And Its Major Western Tributaries In South Dakota, Monica Jean Schwalbach
Conservation Of Least Terns And Piping Plovers Along The Missouri River And Its Major Western Tributaries In South Dakota, Monica Jean Schwalbach
Electronic Theses and Dissertations
Interior least terns (Sterna antillarum) and piping plovers (Charadrius melodus) are listed as endangered or threatened over all of their breeding range, including South Dakota (SD). Investigations were made into the status, distribution, production, habitat characteristics, and factors limiting productivity of least terns and piping plovers in SD. The study area included the Missouri River from the North Dakota state line to Ponca State Park, Nebraska, and the lower 1/3 of the Grand, Moreau, Cheyenne, and White rivers. Least tern numbers increased substantially (253; 367) between 1986 and 1987, but plover numbers increased only slightly (187; 197). Terns and plovers …
Wetland Characteristics Of Avian Cholera Outbreaks And Surface Water Transfer In The Nebraska Rainwater Basin Area, Brian J. Smith
Wetland Characteristics Of Avian Cholera Outbreaks And Surface Water Transfer In The Nebraska Rainwater Basin Area, Brian J. Smith
Electronic Theses and Dissertations
Avian Cholera (Pateurella multocida) has infected and killed thousands of migrating waterfowl each year since 1975 in Nebraska’s rainwater basin area. Disease outbreaks in migrating waterfowl populations just prior to the nesting season are of concern to biologists. Feedlots and itner-wetland basin surface water transfer mechanisms of the avian cholera causative agent, P. multocida, were investigated using remote sensing techniques. Wetland basin characteristics (classification type, adjacent landuse, basin landuse, and basin densities) were also investigated for relationships to 1981 avian cholera outbreaks. No surface drainage relationships were found that would permit the transfer of P. multocida from one wetland basin …
Characterization And Utilization Of High- And Low-Sodium Lignite Of The Beulah-Zap Bed (Paleocene), Indian Head Mine, Southwestern North Dakota, Gale G. Mayer
Theses and Dissertations
A study of high- and low-sodium lignite of the Beulah-Zap bed sampled at the Indian Head Mine, Pit 11 and 12, respectively, in Mercer County, North Dakota and fly ash derived from utilization tests on the lignite, indicates the fly-ash composition and related utilization potential can be correlated to coal geochemistry.
Average lithotype abundances for each of the sampling sites were estimated to be vitrain 50%, attritus 45%, and fusain 5%. Attritus occurs more frequently in the upper part and vitrain in the middle and lower parts of the seam. Maceral groups, identified microscopically, were (in order of decreasing abundance): …
Winter 1988, Nsu Oceanographic Center
Summer 1988, Nsu Oceanographic Center
Spring 1988, Nsu Oceanographic Center
Fall 1988, Nsu Oceanographic Center
Evolutionary Genetics And Morphometrics Of A Cave Crayfish Population From Chiapas (Mexico), Valerio Sbordoni, Giuliana Allegrucci, Fabiola Baldari, Donatella Cesaroni
Evolutionary Genetics And Morphometrics Of A Cave Crayfish Population From Chiapas (Mexico), Valerio Sbordoni, Giuliana Allegrucci, Fabiola Baldari, Donatella Cesaroni
International Journal of Speleology
The recently explored Cueva de Los Camarones, in the remote village of Constitucion, Chiapas, Mexico, houses a unique highly variable population of Procambarus crayfish (Crustacea, Decapoda). Morphologically, a more or less clinal variation is revealed at several features such as the degree of rudimentation in both pigmentation and eye, and the elongation of body and appendages. Extremes are quite different, ranging from typical dark, thick, eyed individuals to light, elongated, microphtalmic phenotypes. Evolutionary relationships among individuals were investigated electrophoretically (25 structural gene loci) and morphometrically (12 characters) by means of multivariate analyses. Results from analysis of individual allozymic multilocus profiles …
Paleoenvironment And Speciation In The Cave Beetle Complex Speonomus Delarouzeei (Coleoptera, Bathysciinae), Christian Juberthie
Paleoenvironment And Speciation In The Cave Beetle Complex Speonomus Delarouzeei (Coleoptera, Bathysciinae), Christian Juberthie
International Journal of Speleology
In the eastern part of the Pyrenees (France) the author describes a scenario of speciation in the cave species complex Speonomus delarouzeei (Coleoptera Bathysciinae); the speciation processes have been initiated by a breakdown of the ecological equilibrium induced during three glacial-interglacial episodes. The scenario is the following: — during the first glaciation (2.3-2.1 MY), psychrophilic populations ancestral to S. brucki were selected over the highest elevation of the range, by means of cold effect which produced an adaptive demographic advantage; adaptive characters of troglobitic species (K strategy) take place presumably in relation to colonization of caves and M.S.S.; — during …
Digital Neural Networks, Tony R. Martinez
Digital Neural Networks, Tony R. Martinez
Faculty Publications
Demands for applications requiring massive parallelism in symbolic environments have given rebirth to research in models labeled as neural networks. These models are made up of many simple nodes which are highly interconnected such that computation takes place as data flows amongst the nodes of the network. To present, most models have proposed nodes based on simple analog functions, where inputs are multiplied by weights and summed, the total then optionally being transformed by an arbitrary function at the node. Learning in these systems is accomplished by adjusting the weights on the input lines. This paper discusses the use of …
University Of Texas At Tyler Catalog, 1988-1990, University Of Texas At Tyler
University Of Texas At Tyler Catalog, 1988-1990, University Of Texas At Tyler
Catalogs
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. In addition, no permission is required from the rights-holder(s) for educational uses. For other uses, you need to obtain permission from the rights-holder(s).
Lake Apopka Trophic Structure Manipulation, Thomas Crisman, John R. Beaver
Lake Apopka Trophic Structure Manipulation, Thomas Crisman, John R. Beaver
School of Geosciences Faculty and Staff Publications
No abstract provided.
Variability Of Surface Pigment Concentrations In The South Atlantic Bight, Charles R. Mcclain, James A. Yoder, L. P. Atkinson, J. O. Blanton, T. N. Lee, J. J. Singer, Frank Muller-Karger
Variability Of Surface Pigment Concentrations In The South Atlantic Bight, Charles R. Mcclain, James A. Yoder, L. P. Atkinson, J. O. Blanton, T. N. Lee, J. J. Singer, Frank Muller-Karger
CCPO Publications
A 1‐year time sequence (November 1978 through October 1979) of surface pigment images from the South Atlantic Bight (SAB) was derived from the Nimbus 7 coastal zone color scanner. This data set is augmented with in situ observations of hydrographic parameters, freshwater discharge, sea level, coastal winds, and currents for the purpose of examining the coupling between physical processes and the spatial and temporal variability of the surface pigment fields. The SAB is divided into three regions: the east Florida shelf, the Georgia‐South Carolina shelf and the Carolina Capes. Six‐month "seasonal" mean pigment fields and time series of mean values …
Stratigraphy, Paleontology And Paleobiogeography Of Lower Vertebrates From The Cedar Mountain Formation (Lower Cretaceous), Emery County, Utah, Michael L. Pomes
Stratigraphy, Paleontology And Paleobiogeography Of Lower Vertebrates From The Cedar Mountain Formation (Lower Cretaceous), Emery County, Utah, Michael L. Pomes
Master's Theses or Doctor of Nursing Practice
Where present, the basal Buckhorn Member of the Cedar Mountain Formation (Aptian-Albian) separates the overlying main member from the mudrocks of the Tithonian Brushy Basin Member of the Morrison Formation. Without the Buckhorn, the mudrocks of the Cedar Mountain Formation appear to grade into those of the Morrison, so one is apt to call the entire sequence Morrison. Where the Cedar Mountain Formation appears to grade in to the Morrison, use of lower vertebrate teeth can provide an additional means to separate the Morrison from the Cedar Mountain Formation. Lower vertebrate teeth and associated microvertebrate remains (eggshell and bone fragments) …
Evaluation Of Possible Reproductively Mediated Character Displacement In The Crayfishes, Orconectes Rusticus And O. Sanbornii, Mark J. Butler Iv
Evaluation Of Possible Reproductively Mediated Character Displacement In The Crayfishes, Orconectes Rusticus And O. Sanbornii, Mark J. Butler Iv
Biological Sciences Faculty Publications
Orconectes rusticus is replacing several species of crayfishes in north-central and northeastern North America, including O. sanbornii in Ohio. Recent evidence suggests that the species replacements may be driven by asymmetrical reproductive success favoring O. rusticus. Nonetheless, some sympatric associations appear locally persistent. Because crayfish demonstrate size assortative mating and there is a disparity in the sizes of the species, further divergence in the sizes of the species in sympatry could enhance reproductive isolation, ultimately providing a mechanism for character displacement. To test this hypothesis the size differentials between crayfish collected from allopatric and sympatric populations in east-central Ohio …
Production Effects Of Biotechnology In The Dairy Industry: An Exploratory Study, Kenneth L. Schurter
Production Effects Of Biotechnology In The Dairy Industry: An Exploratory Study, Kenneth L. Schurter
Theses
Genetically engineered products are being produced at an economical level. products is bovine sornatotropin. One of these Injections of bovine sornatotropin increase milk yield in dairy cattle. This increase in production per cow is consistent with the thirty year trend of fewer dairy farms, fewer cows, and more milk per cow.
Starting in the 1950's in the mechanical era, farmers went from horses to tractors. In the chemical era, herbicides and fertilizers started being used. Now in the 1980's the technical era is coming in to existence . Through all of these era's there was controversy. Each of these era's …
A Study Of Surface Dynamics Of Polymers. Ii. Investigation By Plasma Surface Implantation Of Fluorine–Containing Moieties, T. Yasuda, T. Okuno, K. Yoshida, H. Yasuda
A Study Of Surface Dynamics Of Polymers. Ii. Investigation By Plasma Surface Implantation Of Fluorine–Containing Moieties, T. Yasuda, T. Okuno, K. Yoshida, H. Yasuda
Chemistry Faculty Research & Creative Works
Macromolecules at the surface of a polymeric solid have considerable mobility, and the specific arrangement of functional groups of macromolecules at the surface is dictated by the environmental conditions in which the surface is placed. Consequently, the change of environmental conditions, such as immersion in water or placement in a biological surrounding, could cause a considerable degree of change in the surface characteristics of a polymer from those evaluated in the laboratory against ambient air. The mobile nature of a polymer surface can be investigated by surface‐implanting fluorine‐containing moieties, mainly—CF3, by the plasma implantation technique and following the disappearance and …
Hydrogeology Of The Hillsboro Landfill, Hillsboro, North Dakota, Jeffrey D. Maletzke
Hydrogeology Of The Hillsboro Landfill, Hillsboro, North Dakota, Jeffrey D. Maletzke
Theses and Dissertations
Landfills are the primary means for land disposal of solid wastes, and as such, they represent potential sources of groundwater contamination. This potential for contamination is exemplified by the Hillsboro landfill, which was emplaced above the Hillsboro aquifer, within permeable surface materials, and under shallow water-table conditions. Burial of refuse in trenches 15-feet (4.57 m) deep ensure that at least portions of the refuse are below the water table, which varied from 5.4 to 13.2 feet (1.7 to 4.0 m) below the surface. Concern over these factors led to the present study.
Subsurface conditions were investigated by electrical, earth-resistivity surveying. …
Proceedings Of The 1987 Airlie House Conference On The Resources Planning Act, Clark S. Binkley, Ed, Garry D. Brewer, Ed., V. Alaric Sample, Ed.
Proceedings Of The 1987 Airlie House Conference On The Resources Planning Act, Clark S. Binkley, Ed, Garry D. Brewer, Ed., V. Alaric Sample, Ed.
Yale School of the Environment Bulletin Series
No abstract provided.
Response Of Fish Communities To Habitat Alteration In A Small Ozark Stream, Danny J. Ebert, Stephen P. Filipek
Response Of Fish Communities To Habitat Alteration In A Small Ozark Stream, Danny J. Ebert, Stephen P. Filipek
Journal of the Arkansas Academy of Science
From 1984 to 1986, the Arkansas Highway and Transportation Department reconstructed and upgraded a portion of St. Hwy. 123 west of St. Hwy.7 at Pelsor, Arkansas. As a result of the construction, portions of Haw Creek, Johnson County, Arkansas, a third order stream in the Boston Mountains Ecoregion, were straightened and channelized. In reconstructing specific stream reaches, stream banks were riprapped and vegetated, gabions constructed and positioned, stream substrates and pool-riffle ratios altered. Instream and riparian habitat and fish biomass and diversity in altered reaches were radically altered. Channelized reaches became wide and shallow, lacking overstory cover and pools. Substrate …
Equations Of Variation For Ordinary Differential Equations On Manifolds, J. B. Bennett
Equations Of Variation For Ordinary Differential Equations On Manifolds, J. B. Bennett
Journal of the Arkansas Academy of Science
No abstract provided.
The Effects Of Siltation On Recruitment Of Spiny Lobsters, Panulirus Argus, William F. Herrnkind, Mark J. Butler, Richard A. Tankersley
The Effects Of Siltation On Recruitment Of Spiny Lobsters, Panulirus Argus, William F. Herrnkind, Mark J. Butler, Richard A. Tankersley
Biological Sciences Faculty Publications
Fewer juvenile pinry lobsters were found in areas of the Florida Keys where their primary habitat was heavily silted as compared with similar, less silted habitat. Several hypotheses explaining this relationship were tested, and the time-to-metamorphosis was compared for settling pueruli within silted and nonsilted algae stands. Limited postlarval settlement and avoidance of silted algal habitats by juveniles, probably accounts for the paucity of young lobsters in heavily silted sites. In addition, although juvenile lobsters are nonselective predators, lower prey availability in silted algae probably promotes transciency which, in turn, causes increased mortality by predation while juveniles are exposed.
Magnetite And Magnetotaxis In Microorganisms, Richard B. Frankel, R. P. Blakemore
Magnetite And Magnetotaxis In Microorganisms, Richard B. Frankel, R. P. Blakemore
Physics
No abstract provided.
Fractals With Arbitrary Segment Lengths, Daniel Michael Doerer
Fractals With Arbitrary Segment Lengths, Daniel Michael Doerer
Masters Theses
"Work in the area of fractal geometry has generally focused on a specific facet of the discipline at the expense of other interesting features. This approach often generates more questions than answers for the general audience due to the lack of unification across all views. It appears that a common thread to relate all aspects of fractal characteristics is missing. This paper addresses this question and presents some new and fascinating results. For example, in-depth mathematical analysis often defers to the intriguing and attractive graphical displays produced by mapping the complex plane to the pixel field on a CRT. Both …
Looking At Lupins - Lupin Management In The South Eastern Wheatbelt, W. L. Smart, M. M. Ralph, J. M. Liddle, R.. D. Ramm, C. J. Robinson, E. W. Armstrong
Looking At Lupins - Lupin Management In The South Eastern Wheatbelt, W. L. Smart, M. M. Ralph, J. M. Liddle, R.. D. Ramm, C. J. Robinson, E. W. Armstrong
Grain and other field crops research reports
In the past couple of years research into lupins has increased substantially particularly in the fields of weed control, seeding rates, and control of diseases such as brown leaf spot and pleiochaeta root rot. This report is a summary of the lupin trials in the Lake Grace advisory area as well as a guide to better lupin farming.
Oligocene Calcareous-Nannofossil Biostratigraphy From Leg 101, Site 628, Little Bahama Bank Slope, Michael J. Moran, David K. Watkins
Oligocene Calcareous-Nannofossil Biostratigraphy From Leg 101, Site 628, Little Bahama Bank Slope, Michael J. Moran, David K. Watkins
Department of Earth and Atmospheric Sciences: Faculty Publications
Drilling at Hole 628A, Leg 101 of the Ocean Drilling Program, recovered a thick, relatively complete Oligocene section of nannofossil-foraminifer chalk and ooze. Sediments from Cores 101-628A-16H through 101-628A-29X were examined using the light microscope to provide information about biostratigraphy of calcareous nannofossils. Several authors noted a problem in distinguishing the first appearance of species within the Sphenolithus predistentus-S. ciperoensis lineage of the mid-Oligocene, particularly Sphenolithus ciperoensis, because of the gradual evolution of its members. Successful separation of species in this lineage is critical for accurately dating relative age of mid- and upper-Oligocene nannofossil sediments. Length and taper of …