To determine if preserved museum fish specimens could be used evaluate mercury contamination through time, we preserved largemouth bass (Micropterus salmoides) in formalin-ethanol and formalin-isopropanol and found no significant change in mercury concentration over 160 days. To evaluate how mercury contamination of two rivers in southeastern Oklahoma may have changed through time, we determined mercury concentrations in preserved longear sunfish (Lepomis megalotis) from the Sam Noble Oklahoma Museum of Natural History. Longear sunfish had been collected over 41- and 79-year periods from Glover and Mountain Fork Rivers, respectively. Glover River is unimpounded, whereas Mountain Fork River was impounded upstream from the sampling sites in 1968. Mercury concentrations in longear sunfish from Glover River showed no temporal trend from 1963 to 2004. Mercury concentrations in longear sunfish from Mountain Fork River showed no temporal trend from 1925 to 1993 but then declined from 1993 to 2003.

Aquaporin-9 (AQP9) is a neutral channel, permeable to water, glycerol, and a number of solutes. The presence of AQP9 in retinal ganglion cells (RGCs) was confirmed. AQP9 and a number of proteins responded differently to two animal models of glaucoma. Inhibition of AQP9 may protect RGCs under hypoxia conditions. The expression of AQP9 responded to hypotonic shock in a time-dependent matter. Aquaporin in the RGCs and astrocytes may play a role in cell survival or death, depending on the stimulus. Under some conditions, increasing AQP4 may also be protective, such as in vasogenic edema, whereas under cytotoxic edema it becomes detrimental. This work describes possible physiological and pathophysiological roles of AQP9. Aquaporin-4 is expressed in astrocytes, which are considered RGCs supportive cells. AQP4 may be targeted by the proteasome system, so inhibition of this pathway may be protective in vasogenic brain edema.

College students report stress as a factor hindering academic success. They often engage in non-productive rumination and worry. Problem-based writing, which involves expressing thoughts and feelings related to a distressing event, has been offered as a solution, particularly for rumination. The present research explored the effects of problem-based writing vs. problem-based writing enhanced by a multiple perspective-taking strategy, the Thought Team. This imagined team, formed to assist in problem solving, serves as a connection to a virtual group of advisors, real or imaginary. Participants in the treatment conditions reported that the experimental session had greater meaning, value, and depth than a no treatment control group, yet reported feeling less session smoothness than controls. College students using the Thought Team strategy also reported increased problem solvability (i.e., new perspective and understanding of problems and their elements). This improved solvability may increase motivation to engage in the writing.

This study surveyed mercury concentrations of aquatic macroinvertebrates collected from ephemeral ponds on the Lyndon B. Johnson National Grassland, Texas. Macroinvertebrates representing eight taxonomic groups were collected from 13 ponds in June 2006. Significant differences in mercury concentrations were detected among the taxonomic groups, with the omnivore Hydrophilidae and the predator Notonectidae containing the lowest and highest concentrations of mercury, respectively. I also detected significant differences in mercury concentrations of macroinvertebrates in the different ponds. The mercury concentrations of some macroinvertebrates were above recommended thresholds for consumption by bird species. This study suggests that ephemeral ponds can produce large populations of mercury-contaminated macroinvertebrates that could be harmful to aquatic and terrestrial consumers.

Previous research on college students decision-making has shown they sometimes make impulsive, emotionally influenced, risk-taking and sensation-seeking decisions without fully understanding their decisions or the consequences. Utilizing decision-making components, this study addresses questions of group differences in response to training for decision description, decision mapping, multiple social perspective-taking (SPT), and incubation. The study was conducted in the fall of 2007 with a sample of Texas Christian University undergraduates (n = 283; males = 77, females = 206) enrolled in Psychology coursework. Findings for participants whose intervention included SPT were significantly better able to develop and evaluate decision options, and develop coherent plans for effective decision-making advice than students who did not receive SPT training. Theoretically, it seems likely that SPT participants viewed the strategy as a priming device, bringing out what was already known, rather than providing a new learning experience. Participants receiving decision mapping reported they learned from the intervention and found it useful, but that learning did not translate into being able to enhance their ability to give decision-making advice. Additionally, neither SPT nor mapping contributed to the students decision-making confidence levels. The study addresses a major gap in the college student decision-making literature and provides some preliminary evidence to suggest that the effectiveness of college students decision-making ability will likely increase when provided with simple, yet powerful strategies. Implications and future research needs are also discussed.

The characterization of the vibrational spectra and structures of small metalcarbon (MnCm) clusters is important to the detection of astrophysical species and may elucidate the bonding and growth mechanisms of metallocarbohedrenes, or metcars. Additionally, transition metalcarbon clusters have applications in modern materials science as catalysts for nanomaterial formation. A new experimental apparatus for the preparation of MnCm clusters has been designed and constructed , incorporating a new closed cycle refrigeration system, a chamber for the deposition of samples, associated vacuum system, and a fully automated mechanism to simultaneously translate and rotate carbon and metal rods during laser ablation. A new technique for fabricating carbon rods has been developed to expedite carbon rod production and to facilitate the formation of the MnCm clusters studied. Fourier transform infrared (FTIR) investigations have been done for the first time on transition metalcarbon clusters. The molecular clusters were formed by trapping the products from dual laser ablation of metal and carbon rods in solid Ar at ~10 K. Comparing FTIR measurements of vibrational fundamentals and 13C isotopic shifts with the predictions of density functional theory (DFT) calculations has enabled the identification of five novel metalcarbon molecules, establishing their ground state geometries and permitting the assignment of vibrational fundamentals, including the í1(ó) modes of (5Ð) linear CrC3, (2Ä) linear CoC3, and (2Ð) linear CuC3 at 1789.5, 1918.2, and 1830.0 cm-1, respectively, the í3(óu) =1624.0 and í4(óu)=528.3 cm -1 modes of (1Óg+) linear AlC3Al, and the í2(ó) =1210.9 cm-1 mode of linear AlC3. Evidence for the tentative identification of the í1(a1)=1554.3 cm-1 mode of (3B1) fanlike CrC4 and the í4(óu)=1987.3 cm-1 mode of (1Óg+) linear AlC4Al is also presented. All FTIR measurements of vibrational frequencies and 13C shifts are in very good agreement with DFT predictions, resulting in the first identification of vibrational fundamentals and the characterization of molecular geometries for these species specifically and for transition metalcarbon clusters in general. A catalog of potential VnCm absorptions has also been developed to aid in future vanadium-carbon studies.

This thesis uses Ground Penetrating Radar (GPR) and traditional coring methods to quantify Holocene sedimentation rates in the Trinity River Delta, Texas. Results showed that, while GPR is useful in determining subsurface stratigraphy in coarse-grained environments such as sand bars, it is not useful for subsurface investigations in marshes, where high clay and water content of the sediments attenuate the GPR signal. Radiocarbon dating of shell fragments recovered from sediment cores (292-536cm) ranged from 2.8 to 3.2 Ka. Mean sediment accumulation rates varied between 1.2 and 1.8 mm yr-1 for two areas of the delta, consistent with previous research. At these rates, modern sediment input from the Trinity River is inadequate to account for sediment accretion in the delta. Therefore, other non-fluvial sediment sources must be contributing to the accretion of sediment within the delta.

Hydrilla verticillata is an invasive, aquatic weed that ranges from Florida to California. Hydrilla is believed to only spread vegetatively. Invasive clonal plants are expected to have low genetic variation limiting their ability to develop resistance to herbicides. Contrary to expectations, hydrilla has recently developed resistance to the herbicide used to control the plant. We used microsatellite loci to determine whether hydrilla is a single clone with low genetic diversity. We found high levels of genetic variation within populations of hydrilla. Spatial patterns of genetic diversity, patterns of genetic differences between individuals, and tests for sexual reproduction, indicate that hydrilla has originated from a single clone. Patterns of genetic diversity suggest that somatic mutations arising during vegetative growth are the main source of genetic diversity. Our study provides an example of how a clonally reproducing organism can potentially develop resistance to herbicides by effectively creating its own genetic diversity.

Grassland birds are the most threatened group of birds in North America. Expanding wind energy in the U.S. may be contributing to habitat fragmentation and loss of suitable habitat for grassland birds. I estimated grassland bird density and diversity at three different study sites: grazed grassland with turbines, grazed grassland without wind turbines, and managed grassland (no turbines) interspersed between forest fragments. My study focused on Dickcissels (Spiza americana) and Eastern Meadowlarks (Sturnella magna). Dickcissel density was highest in grazed grasslands without turbines, while Eastern Meadowlark density was highest at the site with turbines. Dickcissels exhibited a complex interaction between turbine and grass height: in the presence of turbines they were denser in tall grasses, which coincided with increasing distance, but in the absence of turbines they were distributed uniformly. In contrast, the density of Eastern Meadowlarks appeared relatively unaffected by either vegetation height or presence of turbines.

This paper explores the impact of organizational attributes on client engagement within substance abuse treatment. While previous research has identified organizational features, including small size, accreditation, and workplace efficacy, that impact client engagement (Broome et al., 2007), the current study sought to explore the impact of staff stress, burnout, and satisfaction. The sample included 89 programs with 445 counseling staff and directors as well as 5,013 clients who completed surveys regarding their work environment or their evaluation of treatment. Conducting moderation and mediation regression analyses, the current study found that staff stress negatively predicted client participation in treatment. Workload and staff influence were found to moderate the positive relationship between staff stress and burnout. Suggestions for future research are discussed.