Showing papers by "University of Oklahoma published in 1987"

Cardiovascular mortality and noncontraceptive use of estrogen in women: results from the Lipid Research Clinics Program Follow-up Study.

Abstract: A cohort of 2270 white women, aged 40-69 years at baseline, were followed for an average of 8.5 years in the Lipid Research Clinics Program Follow-up Study. There were 44 deaths due to cardiovascular disease among the 1677 nonusers of estrogens and six cardiovascular disease deaths among the 593 estrogen users. The age-adjusted relative risk (RR) of cardiovascular disease deaths in users compared with nonusers was 0.34 (95% confidence limits 0.12 to 0.81). After multivariable adjustment for potential confounding factors (age, blood pressure, and smoking), the estimated RR for estrogen use was 0.37 (95% confidence limits 0.16 to 0.88). Analyses were done to explore whether these results could be due to selection bias for estrogen use. However, the prevalence of cardiovascular disease at baseline was slightly higher in estrogen users (12%) than in nonusers (10%); furthermore, the exclusion of all women with prevalent cardiovascular disease at baseline did not alter the apparent protective effect of estrogen use on cardiovascular disease mortality (RR = 0.42, 95% confidence limits 0.13 to 1.10). Additional analyses examining the complex association between estrogen use, lipoprotein levels, and cardiovascular disease mortality suggest that the protective effect of estrogen is substantially mediated through increased high-density lipoprotein levels.

Estimating Trait, Method, and Error Variance: Generalizing across 70 Construct Validation Studies:

Abstract: The authors examine the construct validation results of 70 published data sets. The analysis shows that, on average, traits account for less than 50% of the variance in construct measures. These fi...

Interaction of disturbances in tallgrass prairie: a field experiment'

Abstract: A field study was conducted to address the roles of fire, cattle grazing, and the interaction of these two disturbances on plant species abundance and community structure in a tallgrass prairie. In 1985 and 1986, species composition was sampled in three replicates of the following grassland treatments: ungrazed + unburned (undisturbed), grazed + unburned, ungrazed + burned, and grazed + burned. Cover of the matrix-forming species Andropogon gerardii was significantly greater, while cover of the nonmatrix species Bromus tectorum was significantly lower, on the burned treatments than on the unburned treatments. The number and cover of annuals were significantly higher on the grazed treatments than on the ungrazed treatments. Species richness increased with increasing disturbance intensity. Diversity, however, was lowest on the ungrazed + burned treatment and highest on the grazed + burned treatment. Burning significantly reduced species diversity on ungrazed treatments, and grazing significantly increased diversity on the burned treatment. This study documented the dissimilar effects of different natural disturbances on grass- land species, growth form characteristics, and community structure. In addition, the results emphasize the important role of interaction among disturbances on plant community structure in grasslands.

Supervising Counselors and Therapists: A Developmental Approach

Abstract: Presents a comprehensive approach to clinical supervision through which entry-level counselors become seasoned professionals. It explains the needs and characteristics of trainees and recommends how and when supervisors may intervene to help trainees handle counseling sessions with clients.

Susceptibility of young-of-the-year fishes to downstream displacement by flooding

Abstract: I examined downstream displacement of young-of-the-year fishes (primarily centrarchids and cyprinids less than 25 mm total length, TL) by field sampling of drift during floods and by an experiment conducted in a 4.9-m-long artificial stream channel. The pattern of drift during a June 1985 flood (stage increase of 3.2 m) in Brier Creek, Oklahoma, indicated that both centrarchids and cyprinids smaller than 10 mm TL were extremely susceptible to downstream displacement. Drift rates of larger fish (10–25 mm) during both the June flood and a smaller flood (stage increase of 0.4 m) in July 1985 suggested that these fishes were much less susceptible to displacement. The rapid decline in susceptibility to displacement with increase in size from the field study coincided with results obtained in the artificial channel. These results suggest that the effects of floods on stream fish communities can depend on small differences in the timing of reproduction and of flooding.

Lipoproteins as mediators for the effects of alcohol consumption and cigarette smoking on cardiovascular mortality: results from the lipid research clinics follow-up study

Abstract: Because alcohol consumption is associated with increased high density lipoprotein (HDL) cholesterol and decreased low density lipoprotein (LDL) cholesterol, and cigarette smoking is associated with lower HDL cholesterol and higher LDL cholesterol, there has been speculation that the protective effect of moderate alcohol consumption and/or the noxious effect of cigarette smoking for cardiovascular disease might be mediated in large part by a lipoprotein mechanism. The authors examined this question in a prospective study of 7,461 men and women in 10 North American populations initially seen in 1972-1976 and followed for an average of 8.5 years. Moderate alcohol consumption was weakly protective for cardiovascular disease, while cigarette smoking was strongly and significantly associated with cardiovascular disease mortality. As expected, LDL cholesterol was positively related and HDL cholesterol was inversely related to cardiovascular disease mortality. However, multivariable analysis of cardiovascular disease mortality alternately excluding and including HDL cholesterol and LDL cholesterol as covariates indicated that the effect of alcohol consumption on cardiovascular disease mortality was independent of an LDL cholesterol pathway and only partially mediated by an HDL cholesterol pathway, while the effect of cigarette smoking was independent of both the HDL cholesterol and LDL cholesterol pathways, suggesting alternative biologic mechanisms of action for both alcohol consumption and cigarette smoking on cardiovascular disease.

Numerical Simulation of Thunderstorm Outflow Dynamics. Part I: Outflow Sensitivity Experiments and Turbulence Dynamics

Abstract: In this first paper of a two-part series, a two-dimensional numerical model is developed and used to investigate the dynamics of thunderstorm outflows. By focusing only on the outflow and using essentially inviscid equations and high spatial resolution, we are able to explicitly represent important physical processes such as turbulent mixing. To simplify interpretation of the results, the model atmosphere used in all experiments is calm and dry adiabatic. This approach allows us to establish basic characteristics of modeled outflows in simple physical settings, and provides a foundation for future studies using more realistic environments. All simulated outflows are initialized by prescribing a (controlled) horizontal flux of cold air into the model domain through a lateral boundary. In a series of sensitivity tests, we examine three parameters of the cold air source region: 1) the vertical temperature deficit profile, 2) the magnitude of the temperature deficit, and 3) the cold-air depth. By hol...

A hierarchical consideration of causes and mechanisms of succession

Abstract: Questions of successional pattern and causality have been central concerns in vegetation ecology. In this paper we address the limits of the overextended models of Connell and Slatyer by discussing problems encountered in field tests. To help prevent such problems, we define the essential concepts needed to understand succession: pathway, cause, mechanism, and model. We then suggest a more complete enumeration of successional causes, and place them in a three-level hierarchy. The highest level in the hierarchy defines the general and universal conditions under which succession occurs: (1) availability of open sites, (2) differential availability of species, and (3) differential performance of species at the site. To provide a more detailed understanding of succession, each of these causes is decomposed into ecological processes. A further decomposition results in the third level of the hierarchy, which is required to elucidate the mechanisms of succession at particular sites and to make detailed predictions. The hierarchy allows the appropriate causes to be chosen to answer questions about succession at the desired level of generality or level of organization. Recognizing the appropriate level(s) in the hierarchy is critical for the successful explanation of succession, design of experiments, statement of predictions, construction of models and development of general theory.

Comparing fuzzy logic with classical controller designs

Abstract: A unified approach for comparing the performance of fuzzy and nonfuzzy controller designs is presented. Relationships are established between the gain parameters for the two classes of controller designs. The methods presented apply equally well to proportional-plus-integral, linear multiband, and multilevel relay controllers.

Ischemia-induced neuronal cell death, calcium accumulation, and glial response in the hippocampus of the Mongolian gerbil and protection by propentofylline (HWA 285).

Abstract: The localization and timing of cellular calcium loading and glial cell reaction in relation to selective death of hippocampal neurons was studied in Mongolian gerbils following transient forebrain ichemia. Two days after a 5-min period of ischemia, heavy calcium staining was histochemically demonstrated in circumscribed groups of nerve cells, located in the transition zone between the CA1 and CA3 areas. This preceded complete neuronal cell death that was quantitatively assessed by measuring the intensity of Nissl staining. After a 12-min period of ischemia, extensive calcium loading was observed in conjunction with severe neuronal damage throughout the CA1 region as well in the dorsal nuclei of the thalamus. The extent of calcium staining decreased with time and was not seen at stages later than 7 days. Already at 2 days after a 5-min period of ischemia, a strong increase of glial fibrillary acidic protein immunoreactivity was seen. This indicates a marked and early hypertrophy of astrocytes that was not ...

Inflammation and Repair

Abstract: Inflammation is the reaction of living tissues to various forms of injurious stimuli. It involves vascular, neurologic, humoral and cellular responses. The inflammatory process is designed to destroy, dilute or contain the injurious agent and pave the way for repair.

Evidence for a relationship between hydrocarbons and authigenic magnetite

Abstract: Establishing a relationship between hydrocarbon migration and the precipitation of authigenic magnetite in sedimentary rocks is of significant interest with respect to (1) elucidating mechanisms for remagnetization and establishing the origin of secondary magnetizations residing in magnetite, (2) developing a method to date hydrocarbon migration events by determining the time of remanence acquisition by palaeomagnetic methods, and (3) evaluating whether searching for anomalous concentrations of diagenetic magnetic minerals and/or aeromagnetic anomalies is justified as a relatively inexpensive exploration tool. The direct association of hydrocarbon migration and the precipitation of authigenic magnetite has, however, not been established. In this paper we report palaeomagnetic, rock magnetic, petrographic and geochemical results of a study of samples from Permian spelebthems and gilsonite found in the Ordovician Arbuckle Group in southern Oklahoma. The results indicate that there is a genetic relationship between hydrocarbon migration and the precipitation of authigenic magnetite.

A guide to rotations in quantum mechanics

Abstract: To lay a foundation for the study and use of rotation operators in graduate quantum mechanics and in research, a thorough discussion is presented of rotations in Euclidean three space (R3 ) and of their effect on kets in the Hilbert space of a single particle. The Wigner D-matrices are obtained and used to rotate spherical harmonics. An extensive ready-reference appendix of the properties of these matrices, expressed in a consistent notation, is provided. Careful attention is paid throughout to various conventions (e.g. active versus passive viewpoints) that are used in the literature.

Congenital pigmented and vascular lesions in newborn infants

Abstract: The incidence of congenital cutaneous lesions was ascertained by a single dermatologist in each of 830 sequential newborn infants over a 3-month period at the Oklahoma Teaching Hospitals. Lesions were observed in 57% of infants (77% of blacks and 49% of nonblacks). Vascular lesions were the most frequent, occurring in 44% of neonates. Pigmented lesions other than mongolian spots were observed in 15.8% of blacks and in 1.6% of whites. Clinical criteria do not readily distinguish nevus cell nevi from other pigmented lesions. Wood's light examination did not enhance the identification of congenital lesions. Inadequate examination of infants and marked underreporting of congenital lesions in newborn infants are widespread.

Microbial ecology of a shallow unconfined ground water aquifer polluted by municipal landfill leachate.

Abstract: The microflora of a shallow anoxic aquifer underlying a municipal landfill in Oklahoma was characterized by direct light microscopy, most probable number determinations of sulfate reducers and methanogens, and measurements of methanogenesis in aquifer samples containing either endogenous or exogenous electron donors and various sulfate concentrations. Acridine orange direct counts of bacteria did not vary significantly with time or between 2 major sampling areas (1.70±0.16×107 to 11.2±2.1×107 cells/gdw). One site (B) was high in organic matter and low in sulfate, and methanogens generally outnumbered sulfate-reducers at most times of the year, whereas the opposite was true for another site (A). Greater than 75% of the theoretical amount of methane was detected within 7 weeks in both site A and B aquifer slurries amended with noncompetitive electron donors like methanol and trimethylamine. However, only site B slurries efficiently converted competitive donors like acetate, H2, and formate to the expected amount of methane. A mapping of sulfate and methane levels indicated that site A is relatively localized. These results suggest that the predominant flow of carbon and energy is through methanogenesis at aquifer site B whereas sulfate reduction predominated at site A. However, both methanogens and sulfate reducers could be isolated from either site.

An Experimental Study of the Effectiveness of Negative Political Advertisements.

Abstract: Negative advertising has become an important factor in political campaign communication. Although previous research has suggested possible boomerang effects from such advertising, this experimental study of negative newspaper and television advertising by an “independent” sponsor shows that negative advertising reduces the image evaluation of the targeted politician. While the negative effect was greater for those in the political party opposite that of the targeted politician, respondents of the politician's own party were also affected.

Physical attractiveness and the personality resemblance of identical twins.

Abstract: The physical attractiveness of 25 pairs of monozygotic (MZ) twins was rated independently for twins A and B. The MZ twins were rated alike in their physical attractiveness (r=0.54; corrected for attenuation,r=0.94). Physical attractiveness was uncorrelated with verbal intelligence but was associated, controlling statistically for the sex difference in attractiveness favoring females, with three of the eight traits in the Comrey inventory: Conformity, Extraversion, and Emotional Stability. In both sexes, greater emotional stability was associated with attractiveness; in males greater extraversion; and in females, greater conformity. When these twin correlations were adjusted for this association with attractiveness, the mean change in the value ofr was only 0.03, indicating that physical attractiveness does not appear to bias conclusions from twin studies.

Growth of Syntrophomonas wolfei in pure culture on crotonate

Abstract: A Synthrophomonas wolfei-Methanospirillum hungatei coculture was adapted to catabolize crotonate. S. wolfei was then isolated in axenic culture using agar spread plates and roll tubes with crotonate as the sole energy source. S. wolfei catabolized crotonate via a disproportionation mechanism similar to that of some Clostridium species. Growth on crotonate was very slow (specific growth rate of 0.029 h−1) but the conversion of energy into cell material was very efficient with cell yields of 14.6 g (dry wt.) per mol of crotonate. S. wolfei alone did not catabolize butyrate, but butyrate was stoichiometrically degraded to acetate and presumably methane when S. wolfei was reassociated with M. hungatei. S. wolfei-M. hungatei cocultures accumulated some butyrate during growth on crotonate indicating that protons were not the sole electron acceptors used for crotonate oxidation by the coculture.

Effect of adrenergic and muscarinic cholinergic agonists on atrial natriuretic peptide secretion by isolated rat atria. Potential role of the autonomic nervous system in modulating atrial natriuretic peptide secretion.

Abstract: Stretching of the atrial wall is a known stimulant for atrial natriuretic peptide (ANP) secretion. Little is known about other factors that may influence ANP secretion. We examined the effects of the neurotransmitters of the autonomic nervous system on ANP secretion from isolated rat left atria. Superfusion with 10 muM norepinephrine produced a biphasic rise in ANP secretion with a peak response 2.5-fold above baseline secretion. To determine whether the response to norepinephrine primarily reflected alpha- or beta-adrenergic receptor stimulation, atria were superfused with 0.1 muM isoproterenol or 10 muM phenylephrine and 1 muM propranolol. ANP secretion in response to isoproterenol was biphasic, similar to the response to norepinephrine. Phenylephrine evoked a monophasic ANP secretory response, which was delayed in onset relative to that of isoproterenol or norepinephrine. Superfusion with 10 muM methacholine alone had no effect on ANP secretion, but rapidly attenuated norepinephrine-stimulated secretion by 67%. From these observations we conclude: (a) Both alpha- and beta-adrenergic agonists directly and distinctively stimulate ANP secretion; (b) Norepinephrine stimulates ANP secretion by both alpha- and beta-adrenergic mechanisms, however the secretory response pattern of norepinephrine reflects a predominence of beta-adrenergic activity; (c) Under basal conditions, methacholine does not influence ANP secretion; and (d) Methacholine inhibits norepinephrine-stimulated ANP secretion. Thus, in vivo, activation of the sympathetic nervous system may enhance ANP secretion, whereas a rise in parasympathetic tone may lower ANP secretion.

Abdomen and Pelvis

Abstract: Portion of thoracoabdominal cavity inferior to respiratory diaphragm, traditionally divided into larger abdominal cavity and smaller pelvic cavity. Plane of division is pelvic brim, i.e., superior inlet of pelvis.

Responses of stream algae to grazing minnows and nutrients: a field test for interactions.

Abstract: Previous studies have shown that an algivorous grazing minnow (Campostoma anomalum) is the major herbivore in Brier Creek, a hardwater stream in south central Oklahoma. In summer and autumn schools of Campostoma virtually eliminate algae from substrate surfaces in deeper areas of some pools. The pool-to-pool distributions of algae and Campostoma reported for this stream could occur if nutrient limitation permits grazing by Campostoma to "outrun" algal growth. To test this hypothesis, mesh pens were built to exclude Campostoma from substrates in each of four typical Campostoma pools. N+P+K lawn fertilizer was added daily to two of the four pools; the other two, which received no fertilizer additions and which were not visibly affected by fertilizer transported downstream from the pools enriched with nutrients, served as controls. Algae accumulated rapidly on natural substrates and on unglazed ceramic tiles in grazer-exclusion pens in pools receiving N+P+K additions and more slowly in pens in both control pools. Periphyton biomass on grazed substrates in all four pools remained low throughout the experiment. Hence, Campostoma at normal densities were able to outrun algal growth even when nutrients were added. Eleven days after the experiment started, I determined biomass, biomass-specific net primary productivity, and areal net primary productivity of periphyton on substrates exposed to all combinations of grazer (+,0) and nutrient (+,0) treatments. Grazing increased biomass-specific primary productivity, prevented accumulation of biomass, and decreased areal primary productivity of periphyton. Additions of N+P+K increased biomass-specific net primary productivity of grazed and ungrazed periphyton and markedly increased biomass of periphyton on substrates protected from Campostoma. Although food supply for Campostoma appeared to be greater with nutrient additions, condition of Campostoma in pools receiving N+P+K was not significantly different from Campostoma collected from control pools 35 days after the experiment started. I conclude that although nutrient supply limits biomass-specific primary productivity of periphyton in Brier Creek, nutrient limitation in this stream exacerbates, rather than causes, the visually conspicuous pool-to-pool complimentary distribution of algae and Campostoma: in this stream, grazing by Campostoma at natural densities can outrun periphyton growth even when nutrients are added.

Operative treatment of Medial epicondyle fractures in children.

Abstract: Thirty-one patients with fractures of the medial epicondyle displaced more than 2 mm were evaluated an average of four years after their injury. Twenty-three patients had good results regardless of the degree of displacement or the presence of an elbow dislocation. One patient, had a poor result due to a technical error in pin placement. The remaining seven patients had the fracture fragment trapped in the joint and did worse, with three poor results. There was no correlation between range of motion and degree of displacement, length of immobilization, time from injury to surgery, presence of a dislocation, or open versus percutaneous treatment. Operative treatment of medial epicondyle fractures displaced greater than 2 mm gave consistently good results with a good range of motion, good stability, no ulnar nerve symptoms, and no deformity.

Siblicide, parent-offspring conflict, and unequal parental investment by egrets and herons

Abstract: O'Connor (1978) generated behavioral predictions from Trivers's (1974) theory of parent-offspring conflict (POC) in relation to avian brood reduction, especially for species using escalated sibling aggression. In general, when daily mortality rates fall between certain values (the “mortality difference thresholds” for parents and surviving offspring: O'Connor 1978), POC is expected. At such times parents and the early-hatching “senior” offspring are expected to disagree on the necessity, or at least timing, of the “victim” chick's death. Because that death is promoted directly by the senior chicks and because parents have realistic means of nullifying those efforts, behavioral conflict is expected. I examined the activities of all family members in one siblicidal (great egrets, Casmerodius albus) and one nonsiblicidal brood-reducing species (great blue herons, Ardea herodias) of ardeidae in Texas nesting colonies. Daily mortality rates over two breeding seasons approximated the predicted POC zone for four-chick (“B/4”) heron broods and three-chick (B/3) egret broods. As predicted, egret sibling aggression was significantly lower in two-chick broods. Herons seldom fought, regardless of brood size. Special attention was paid to the egret B/3 data for behavioral manifestations of POC. Parents did not interfere overtly with sibling fights (99.2% of 2,829), but parents seemed to have a subtle mollifying effect on the aggression (fewer “sever” fights occurred when parents were present). Parents showed no favoritism in food distribution to dying victim chicks. The mixed results are consistent with two rather different POC interpretations: (1) that significant conflict exists and the offspring are “winning” or (2) that there is no significant evolutionary conflict. In the latter case, parents are regarded as creating asymmetries among offspring (e.g., via hatch asynchrony), then leaving competition among siblings to run its course without further intervention (“laissezfaire” policy). This view explicitly recognizes that siblicide and other investment-skewing selfish chick behaviors may serve parental interests well-i.e., that equal allocation of resources is not likely to be the parental optimum. Using the relative reproductive values of each nestling as an index of the parent's unequal parental investment optimum produces a closer fit to the observed food distribution skew, but does not resolve the question of whether conflict remains.