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Evaluation of a Constructed Wetland to Reduce Toxicity from Diazinon at the Pecan Creek Wastewater Treatment Plant, Denton, TX

Description: The City of Denton Pecan Creek Wastewater Treatment Facility has periodically failed effluent toxicity testing. A Toxicity Identification Evaluation has determined that Diazinon in the effluent is contributing to the observed toxicity. Chlorpyrifos is also implicated as a factor. The City of Denton constructed a half acre experimental wetland to remove Diazinon related toxicity. Results from spiking and microcosm experiments indicate that the wetland can reduce the Diazinon.
Date: May 1996
Creator: Baerenklau, Amy L. (Amy Lyn)
Partner: UNT Libraries
open access

The Influence of a Return of Native Grasslands upon the Ecology and Distribution of Small Rodents in Big Bend National Park

Description: In the southwestern United States there is a delicate balance between the existing grasslands and the rodent fauna. The purpose of this investigation was to determine the influence of secondary succession of native grasslands upon the ecology and distribution of small rodents. Two methods of determining the rodent species were plot quadrates and trap lines using Sherman live traps.
Date: August 1971
Creator: Baccus, John T.
Partner: UNT Libraries
open access

A Comparison of Predicted and Actual Trophic Status of Lake Ray Roberts, Texas Based on Chlorophyll A

Description: Two years before impoundment, the trophic status of Lake Ray Roberts was predicted by applying the total phosphorus input into the Organization for Economic Cooperation and Development (OECD) eutrophication model. Predicted mean summer epilimnetic (MSE) chlorophyll a of Elm Fork arm, Isle duBois arm and Main Body were in the eutrophic category of the OECD model. Observed MSE chlorophyll a two years after impoundment of Elm Fork arm, Isle duBois and Main Body had not reached their predicted mean… more
Date: May 1999
Creator: Lytle, Lili Lisa
Partner: UNT Libraries
open access

A Two Semester Life Science Syllabus for Use in Texas Public Schools with Seventh Grade Students

Description: The problem of using a state adopted textbook written to apply to a large body of students with varying interests and needs was overcome by using a detailed syllabus that arranged course content in a meaningful sequence that appealed to student interest. The outlined syllabus prepared a two semester life science curriculum to be used by the teacher to guide lesson planning. Both semesters were divided into three units each. Materials included in the syllabus were given to actual student groups … more
Date: May 1995
Creator: Edwards, Gail G. (Gail Graham)
Partner: UNT Libraries
open access

Primary Productivity and Nutrient Relationships in Garza-Little Elm Reservoir

Description: A large, multi-basin, reservoir (Garza-Little Elm Reservoir) in north central Texas was studied to determine the relative effects of various parameters on primary productivity. The basins were impounded several years apart,thus allowing the influence of age on water chemistry and biota to be considered. Another principal influence on water quality was secondary sewage effluent that entered one basin from a nearby source.
Date: May 1973
Creator: Smith, Jerry Allen
Partner: UNT Libraries
open access

Underwater Optical Properties of Lake Texoma (Oklahoma-Texas) Using Secchi Disk, Submarine Photometer, and High-Resolution Spectroscopy

Description: The underwater optical climate of Lake Texoma was measured at eleven fixed stations from August 1996 to August 1997. Secchi transparency and submarine photometry characterized seasonal and spatial values of secchi depth (SD), vertical attenuation coefficient (η''), and depth of euphotic zone (Zeu). Indices of Zeu:SD and η'' × SD were compared with universally applied values derived from inland and coastal waters. Turbidity explained 76% of the variation (p = 0.0001) of η'' among water quality p… more
Date: August 1998
Creator: Rolbiecki, David A. (David Alan)
Partner: UNT Libraries
open access

Temporal and Spatial Comparisons of Ambient Toxicity of the Trinity River in Relationship to an Effluent

Description: A toxicological study was initiated because of concerns about allegations that the Texas Water Commission that effluent from the Dallas Central Wastewater Treatment Plant, which discharges into the Trinity River, was affecting downstream water quality. Monthly, flow-weighted composite effluent samples were collected. Grab samples were also collected upstream and downstream from the effluent from April 1989 to August 1991. Toxicity tests were conducted on these samples using Ceriodaphnia dubia a… more
Date: December 1993
Creator: Hall, David B., 1958-
Partner: UNT Libraries
open access

Fitness-Related Alterations in Blood Pressure Control: The Role of the Autonomic Nervous System

Description: Baroreflex function and cardiovascular responses to lower body negative pressure during selective autonomic blockade were evaluated in endurance exercise trained (ET) and untrained (UT) men. Baroreflex function was evaluated using a progressive intravenous infusion of phenylephrine HCL (PE) to a maximum of 0.12 mg/min. Heart rate, arterial blood pressure, cardiac output and forearm blood flow were measured at each infusion rate of PE. The reduction in forearm blood flow and concomitant rise in … more
Date: December 1986
Creator: Smith, Michael Lamar, 1957-
Partner: UNT Libraries
open access

Life History Energetics of The Red-Eared Turtle, Pseudemys scripta in North Central Texas

Description: A population of the red-eared slider, Pseudemys scripta, in north central Texas was studied from 1975 to 1980. A life history energy budget was developed for a typical individual in the population and the population dynamics were estimated. A growth model relating growth rate to mean plastron length (PL) was developed from recapture data and used to 1) establish age classes and 2) age individuals. Growth rate was highly variable in both sexes. Females grew more rapidly than males and attained a… more
Date: December 1984
Creator: Glidewell, Jerry Ray, 1945-
Partner: UNT Libraries
open access

Biology and Production of Net-Spinning Caddisflies (Hydropsychidae And Philopotamidae) in a Regulated Portion Of The Brazos River, Texas

Description: Four species of net-spinning caddisflies, Hydropsyche simulans Ross, Cheumatopsyche lasia Ross, Cheumatopsyche campyla Ross and Chimarra obscura (Walker) are common in the regulated portions of the Brazos River. Hydropsyche simulans spun capture nets with the largest meshdimensions; the two Cheumatopsyche species' nets had the next largest meshes, and Chimarra obscura spun nets with the smallest dimensions. Cheumatopsyche lasia and C. campyla constructed nets with similar sized meshes. The numb… more
Date: May 1984
Creator: Malas, Diane M. (Diane Mary)
Partner: UNT Libraries
open access

A Limnological Study of Lake Worth

Description: This thesis presents the results of a three year study devoted to discovering the life and phenomena found in Lake Worth near Fort Worth, Texas.
Date: August 1939
Creator: Johns, William Barnette
Partner: UNT Libraries
open access

Multivariate Analyses of Amphibian and Reptilian Distribution in Texas

Description: Presence-absence data for amphibians, chelonians, saurians, ophidians, and the terrestrial and aquatic ecological guilds of reptilians were analyzed using multivariate analyses. Geographically consistant distributional patterns were found for all faunal groupings. The correspondence between analyses of the different taxa and guilds was not perfect, but similarities were found. All analyses agreed on the presence of a distinctive region in east Texas. Most analyses also agreed on the presence of… more
Date: August 1988
Creator: Ward, Rocky
Partner: UNT Libraries
open access

Systematics of Coccidian Parasites (Apicomplexa) from Amphibians and Reptiles in Northcentral Texas

Description: Between February 1986 and October 1988, 863 amphibians and reptiles were collected in northcentral Texas and examined for coccidial parasites. Thirteen percent of amphibians <26% salamanders, 11% frogs and toads) and 28% of reptiles (54% turtles, 25% snakes) harbored 20 previously described and 16 new species of coccidia; overall prevalence of infection was 176/863 < 20%). Sixteen Ambvstoma texanum were infected with Eimeria ambystomae which represents new host and geographic locality records f… more
Date: December 1989
Creator: McAllister, Chris Thomas
Partner: UNT Libraries
open access

Toxicological Characterization of Trinity River Sediments

Description: Sediments in the Trinity River were chemically, physically and biologically characterized and assessed for toxicity. Laboratory bioassays were conducted to identify sediments which induced toxic responses in test organisms and to document these responses through time. Metal and organic contaminant concentrations in bottom sediments were measured. Relationships between these concentrations and biological responses observed in laboratory bioassays were determined. Toxicity identification / reduct… more
Date: December 1989
Creator: Hall, Jerry F. (Jerry Fowler)
Partner: UNT Libraries
open access

An Analysis of the Seasonal Food Habits of Two Species of Texas Centrarchids

Description: This thesis explores the feeding habits of sunfish and bluegill in Texas lakes. Data gathered for this study is aimed to aid conservation of these pan fish by making a contribution toward a greater life history understanding of each species.
Date: August 1940
Creator: Faggard, John M.
Partner: UNT Libraries
open access

Development of a Watershed Prioritization Strategy Using Remote Sensing and the Geographic Resource Analysis Support System. Case study: City of Carrollton, Texas

Description: This study used a geographic information system (GIS) and an empirical pollutant load model to estimate average annual pollutant loads contained in storm water charges from the City of Carrollton, Texas. The Geographic Resource Analyses Support System (GRASS) was used to create a number of spatial data layers as input variables to a model that estimates loads in Kilograms/Hectare/Year, and Kilogram/Basin/Year. Average annual pollutant loads for twelve pollutants were derived from average annual… more
Date: December 1996
Creator: Coffey, Jeffery M. (Jeffery Morgan)
Partner: UNT Libraries
open access

Bottom Fauna of Lake Worth

Description: This thesis describes the vertical distribution, quality, and quantity of the fauna found at the bottom of Lake Worth in Texas.
Date: August 1940
Creator: Jenkins, Jesse Denney
Partner: UNT Libraries
open access

A Net Plankton Survey of a Small Perennial Pond

Description: This thesis resulted from an examination of Lake Worth plankton in comparison to plankton found in similar bodies of water throughout the United States.
Date: August 1940
Creator: Legett, Jesse Harrison
Partner: UNT Libraries
open access

Assessment of Changes in Aquatic Macrophyte Occurrence Following Introduction of Triploid Grass Carp in a North Texas Reservoir

Description: The objectives of this project were to measure changes in frequency of occurrence of submerged macrophytes over the first two growing seasons following stocking with triploid grass carp at two fish per acre and to measure differences in macrophyte biomass between areas excluded from herbivory and adjacent control sites after 16 months following establishment of exclosures. The project also seeks to measure concentrations of fluridone following the herbicide treatment, and to compare two methods… more
Date: August 1997
Creator: Bickel, Ken (Kenneth E.)
Partner: UNT Libraries
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