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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

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

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

Degradation of Phenolic Acids by Azotobacter Species Isolated from Sorghum Fields

Description: Sorghum plants excrete phenolic acids which reduce subsequent crop yields. These acids accumulate in field soil by combining with soil and clay particles to form stable complexes which remain until degraded by bacterial metabolism. The amount of phenolic acids in soil samples were obtained by gas chromatography measurements, while Azotobacter populations were obtained by plate counts in 40 sorghum field samples from Denton County, Texas. One can conclude that increasing the Azotobacter populati… more
Date: August 1989
Creator: Al-Hadhrami, Mohamed N. (Mohamed Nasser)
Partner: UNT Libraries
open access

Physiological Ecology, Population Genetic Responses and Assemblage Stability of Fishes in Two Southwestern Intermittent Stream Systems

Description: Six sites within the Denton and Hickory Creek watersheds were sampled over three years to assess the impact of seasonal intermittent stream conditions on the ichthyofauna. An integrated approach using field and laboratory techniques was employed to evaluate the responses of the fishes.
Date: December 1991
Creator: Rutledge, Charles Jerry, 1941-
Partner: UNT Libraries
open access

The Effects of Organic Surface Amendments on Soil Nutrients and Initial Tree Establishment

Description: This study examined the effects of replicating woodland soil surface horizonation on the nutrient status of underlying soils and the initial establishment and growth of trees. A total of 283 container grown trees were planted in a bufferzone around a future landfill site. Control amendments consisted of an 8 cm layer (0.5 m3) of wood chips applied in a circular area of 4.6 m2 around the trees' planting pit. For the treatment, a 2.5 cm layer of composted biosolids (0.15 m3 or 80 Mg/ha) was appli… more
Date: May 1999
Creator: Thuesen, Kevin (Kevin Andrew)
Partner: UNT Libraries
open access

Seasonal Variations in Microflora of Four Denton County, Texas, Clay Soils

Description: This investigation has for its aim the confirmation of the correlation between soil moisture and the microflora of soils, and a lesser relation between the soil temperature and the microflora. The soils used in this study are typical clay soils of Denton County, Texas. The samples were taken from virgin pasture lands and analyses made monthly or semimonthly. The wide seasonal variation of temperature and rainfall afford a good opportunity for this study.
Date: 1941
Creator: Manire, Philip
Partner: UNT Libraries
open access

The Phototropic Properties of Lactuca Ludoviciana (Nutt.) DC. and Silphium Laciniatum L.

Description: This paper deals with certain phases of phototropic properties of two exceptional plants, the pertinent behavior of each being decidedly individualistic and in remarkable contrast to that of herbaceous plants in general. The prickly lettuce, Lactuca ludoviciana (Nutt.) DC. and the rosinweed, Silphium laciniatum L., two common Denton County, Texas, plants, have been selected for this study.
Date: 1941
Creator: Neal, George C.
Partner: UNT Libraries
open access

Sanitary Aspects of the Swimming Pool of North Texas State Teachers College, Denton, Texas

Description: This investigation was conducted in order to show that insanitary conditions may exist in the swimming pool at North Texas State Teachers College provided the proper precautions are not taken; and, in contrast that this pool can be sanitary and entirely safe when operated and used according to the necessary sanitary specifications.
Date: 1943
Creator: Self, Louise
Partner: UNT Libraries
open access

The Dynamics of a Planktonic Microcrustacean Community in a Small North Central Texas Pond Ecosystem

Description: Seven species of planktonic microcrustacea were identified from the North Texas State University Golf Course Pond. Total adult microcrustacean community density, biomass and biocontent, and seasonal cycles of each species were compared with northern populations. Species diversity and evenness indices were highest in summer and lowest in spring. Variations in microcrustacean density showed a positive correlation with density of phytoplankton. Temperature had a direct effect on metabolic rates of… more
Date: December 1976
Creator: Smith, George Arthur
Partner: UNT Libraries
open access

Microflora Found in a Selected Group of Food Products Enclosed in a Protective Wrapper

Description: The purposes of this study are, first, to determine relative numbers and predominant types of bacterial organisms in the various food products studied; second, to evaluate the efficiency of the paper coverings of these foods; and third, to determine whether these products are potential sources of food poisoning.
Date: 1949
Creator: Ogden, William H.
Partner: UNT Libraries
open access

Population Dynamics and Community Structure of Mosquitoes (Diptera: Culicidae) Recorded in Denton, Texas from 2005 to 2015

Description: A population survey was conducted on the mosquito species recorded in Denton, Texas for the years of 2005 to 2015. Data used in this project were obtained from an ongoing, long-term surveillance program led by the City of Denton and conducted through the University of North Texas. Research focused on the population dynamics and community structure of mosquitoes collected within urban areas of Denton, Texas in relation to certain environmental variables. A total of 80,837 female mosquitoes were … more
Date: May 2018
Creator: Hambrick, Bethany Lynn
Partner: UNT Libraries
open access

Studies of Fungal Antagonism in a Norfolk Fine Sand, Denton County, Texas

Description: This investigation has had for its primary purpose the noting of the incidence of antagonists as occurring in a Denton County, Texas, Norfolk Fine Sand. A further interest has been the determination of the effect of these antagonists upon known beneficial soil organisms.
Date: 1948
Creator: Frenzel, Louis D., Jr.
Partner: UNT Libraries
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