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Assessment of Radio-Tagged Grass Carp (Ctenopharnygodon idella) Dispersion, Vegetation, and Temperature Preferences in North Lake Reservoir (open access)

Assessment of Radio-Tagged Grass Carp (Ctenopharnygodon idella) Dispersion, Vegetation, and Temperature Preferences in North Lake Reservoir

Twenty-nine (Group One, June 8,1995) grass carp (Ctenopharyngodon idella) and five (Group Two, April 18, 1996) grass carp were radio-tagged to monitor movement patterns and habitat preferences on North Lake, a 335 hectare multi-use reservoir located in Irving, Texas. Overall fish mean Average Daily Movement (ADM) rates were 49.2 meters/day (during Half One, 6/8/95-11/30/95) and 5.3 meters/day (during Half Two, 12/14/95-6/6/96). Aquatic macrophtye distribution data were obtained. Radio-tagged grass carp were located in Hydrilla verticillata infested areas increasingly throughout the study, however, percent frequency of Hydrilla along 15 transects did not decrease. Radio-transmitters were equipped with temperature-sensors (10-35 Celsius range). Results indicated that radio-tagged grass carp showed no avoidance of areas of North Lake with elevated water temperatures. Radio-tagged grass carp dispersed quickly from stocking point, then moved into littoral areas infested with Hydrilla. After an initial movement period, most fish remained in a localized area.
Date: August 1996
Creator: Lacewell, Jason (Jason Lawrence)
System: The UNT Digital Library
The Use of Similarity Indicies to Assess the Spatial Differences of the Phytoplankton Communities in Lake Ray Roberts, Texas (open access)

The Use of Similarity Indicies to Assess the Spatial Differences of the Phytoplankton Communities in Lake Ray Roberts, Texas

A study of the phytoplankton communities of Lake Ray Roberts was conducted at three sampling sites on two sampling dates during the summer of 1995, assessing both community structure and chlorophyll a concentrations. Eight similarity indices were then used to characterize and compare the communities of these sites. Both community similarity and chlorophyll a concentrations were evaluated using a minimum detectable difference equation to determine the amount of change that must occur in these parameters in order to be deemed statistically significant. The Bray-Curtis Index was shown to be the most adequate index evaluated, and was subsequently used in conjunction with bootstrap analysis to determine the similarity between the three sampling sites.
Date: August 1996
Creator: Banks, Kenneth E. (Kenneth Edward)
System: The UNT Digital Library
Evaluation of a Constructed Wetland to Reduce Toxicity from Diazinon at the Pecan Creek Wastewater Treatment Plant, Denton, TX (open access)

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

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)
System: The UNT Digital Library
Short Term Effects of External Electric Fields on Electrical Activity of the Pineal Gland in Rats (open access)

Short Term Effects of External Electric Fields on Electrical Activity of the Pineal Gland in Rats

The effects of short term exposure (5 minutes) to EEFs at relatively high dosages (10, 25, 39, kV/m) on the electrical activity in rat pineal glands was studied. Daytime and nighttime recordings were taken from an implanted microelectrode in the gland. The data show that (1) both the activity and frequency were enhanced when the animals were exposed to EEFs at 39 kV/m continuously and discontinuously; (2) the later condition yielded a sustained increase (36%) whereas the former a brief (10 sec) increase. This enhancement was statistically significant under both conditions (day and night). The effects observed were thought to be due to membrane alterations either in the pineal gland itself or in the neural inputs to the gland.
Date: May 1996
Creator: Vu, Hung Quoc
System: The UNT Digital Library