The biology of Anisota senatoria J. E. Smith (Lepidoptera: Saturniidae) was examined through ecological studies of within-tree distribution and dispersion, and the influence of a tree growth regulator on development and survival. Biological characteristics examined egg mass size and development, pheromone attraction, response to blacklight traps, adult emergence, laboratory development, pupal mortality and comparison of first versus second generation development time, fecundity and amount of infestation. Within-tree distribution of life stages showed significant differences between low (1.7-3.6 min height), middle (3.7-5.5 m) and high (5.6-7.6 m) strata. Dispersion indices generated from Taylor’s power law showed aggregation was greatest among early instars, followed by third instars and late instars. A fixed level precision sampling plan was developed based on the number of eggs and early instars present in low strata. The tree growth regulator paclobutrazol significantly reduced Q. Phellos L., willow oak, growth, especially one and two years posttreatment. One year posttreatment, paclobutrazol treatments significantly slowed development and decreased survival of early instars, but the opposite relationship was found with late instars. Behavior studies showed that increased A. senatoria survival occurred with increased group size. Laboratory and field experiments revealed critical group sizes for survival of 1-3 larvae and between 25-50 larvae. Anisota senatoria defoliation impact and frass were measured. Growth and root starch were significantly reduced with increased defoliation in Quercus palustris Muench., pin oak, but Q. phellos root starch was not reduced. Reduction in starch content in Q. palustris may have been related to additional stress factors. Landscape fabrics were a reliable sampling method for frass. Frass was used as a method for differentiating larval instars and predicted defoliatioonf Q. palustris. An integrated pest management (IPM) program was developed that included information on native parasites, host plant preference, a citizen survey, and aesthetic indicators. Four egg parasite species including an Aprostocetus new species, five larval parasites and eight hyperparasites were collected. Host plant preference experiments indicated that Q. alba L., white oak, was least preferred by A. senatoria. A citizen survey provided a framework for designing an IPM program. Monitoring and establishing an aesthetic injury level of 25% defoliation decreased pesticide volume without an attendant increase in damage. The number of egg masses (threshold) that caused 25% defoliation ranged from one to nine. / Ph. D.

The production control system of a shop consists of three stages: due-date prediction, order release, and job dispatching. The literature has dealt thoroughly with the third stage, but there is a paucity of study on either of the first two stages or on interaction between the stages. This dissertation focuses on the first stage of production control, due-date prediction, by examining methodologies for improved prediction that go beyond either practitioner or published approaches. In particular, artificial neural networks and regression nonlinear in its variables are considered. In addition, interactive effects with the third stage, shop-floor dispatching, are taken into consideration. The dissertation conducts three basic studies. The first examines neural networks and regression nonlinear in its variables as alternatives to conventional due-date prediction. The second proposes a new cost-based criterion and prediction methodology that explicitly includes costs of earliness and tardiness directly in the forecast; these costs may differ in form and/or degree from each other. And third, the benefit of tying together the first and third stages of production control is explored. The studies are conducted by statistically analyzing data generated from simulated shops. Results of the first study conclude that both neural networks and regression nonlinear in its variables are preferred significantly to approaches advanced to date in the literature and in practice. Moreover, in the second study, it is found that the consequences of not using the cost-based criterion can be profound, particularly if a firm's cost function is asymmetric about the due date. Finally, it is discovered that the integrative, interactive methodology developed in the third study is significantly superior to the current non-integrative and non-interactive approaches. In particular, interactive neural network prediction is found to excel in the presence of asymmetric cost functions, whereas regression nonlinear in its variables is preferable under symmetric costs. / Ph. D.

Two studies were conducted to determine if 7-d MGA or PRID treatment initiated on d 17 of the estrous cycle altered: 1) follicular development, 2) estradiol-17β (E2) and progesterone (P4) concentrations, and 3) patterns of release of luteinizing hormone (LH). In both studies, Angus, Angus x Holstein or Holstein cows 2 to 6 yr of age were randomly assigned to receive either MGA (.5 mg⋅hd⁻¹⋅d⁻¹; n = 23) or PRID (n = 26) for 7 d or to serve as untreated controls (n = 14). Real time, B-mode ultrasound, equipped with a 7.5 mHz linear-array transrectal transducer, was used to conduct daily ovarian scans beginning 3 (Study 1) or 9 d (Study 2) after onset of estrus. Jugular venous blood samples (45 ml) were collected coincident with ovarian scans. In study 2, cows were fitted with indwelling jugular catheters 17 (Control, MGA and PRID), 20 and 23 d (MGA and PRID) after onset of estrus and blood samples were collected at 15-min intervals for 6 h for determination of LH. Interestrus interval was extended (P<.05) for 3 to 5 d in MGA-treated cows exhibiting two or three dominant follicles (classified as MGA-2 and MGA-3, respectively) or PRID-treated cows compared to controls exhibiting two or three dominant follicles during the estrous cycle (control-2 and control-3, respectively). Forty-four percent of MGA-treated cows ovulated the dominant follicle present at the beginning of MGA treatment. In both studies, days from detection of the ovulatory follicle until ovulation were greater (P<.01) in MGA-2 and control-2 cows than control-3, MGA-3 and PRID cows. Diameter of the ovulatory follicle was greater (P<.01) 9 d before estrus and growth rate of the ovulatory follicle was less (P<.02) in MGA-2 and control- 2 cows than control-3, MGA-3 and PRID cows. Serum P4 decreased 3 d earlier (P<.02) during the estrous cycle of MGA-2 and control-2 cows than control-3, MGA-3 and PRID cows. Serum E2 was greater (P<.01) 7 d before estrus in MGA-2 cows than all other treatment groups. Changes in mean and baseline LH concentrations and amplitude of LH pulses on d 17, 20 and 23 after onset of estrus did not differ (P>.10) among treatments. Luteinizing hormone pulse frequency was greater (P<.03) on d-20 after onset of estrus in MGA-2 cows than MGA-3 and PRID cows (4.3 ± .6 vs 2.6 ± .3 and 3.2 ± .4, respectively). In addition, LH pulse frequency did not differ (P>.10) 17 or 23 d after onset of estrus among treatments. In conclusion, MGA treatment extended the dominance phase of development of ovulatory follicles, which resulted in the premature increase in serum E2 and frequency of LH release, whereas the dominant follicle present at the beginning of PRID treatment underwent atresia and another preovulatory follicle developed. / Ph. D.

The oxidative addition of H-H to iridium(l) trimethylphosphine complexes was studied and the reactivity of the resulting water soluble dihydrido iridium (III) complexes was investigated. One Dihydrido iridium(III) complex, mer-Ir(H)₂(PMe₃)₃CI <b>(2)</b> was characterized by ¹H, ³¹p and ¹³C NMR spectroscopy, CH analysis and single crystal xray diffraction. <b>(2)</b> reacted with the strong sigma donor PMe₃ to form [IrH2(PMe₃)4]CI <b>(3b)</b> without having to remove the chloride ligand. <b>(2)</b> reacted with monosubstituted acetylenes and an internal diyne in water to form the vinyl complexes Ir(H)(C(R')=C(H)-(R))(PMe₃)₃CI (R = CMe₃, C₆H₅, SiMe₃, R' = H, <b>(4)-(6);</b> R' = CCMe₃, R= Me, <b>(7)). (2)</b> also reacted in water with ethynylpyridine to form an unusual metallacycle "trimer" <b>(8)</b>. A mechanism for tltrimerizationtl is proposed. <b>(2)</b> also reacted with ethylene in water to form the diethyl iridium complex Ir(CH₂CH₃)₂(PMe₃)₃CI <b>(8)</b>. Encouraged by these results, catalytic hydrogenation of unsaturates in water was investigated. It was found that <b>(2)</b> is active as a water soluble catalyst for hydrogenation of unsaturates. A mechanism for catalytic hydrogenation was proposed. / Ph. D.

An experimental analysis was conducted on a bimaterial plate of steel and brass, subjected to a uniform temperature change. The steel and brass portions of the plate were joined along a common edge with a nearly zero thickness medium. Whole-field, in-plane displacement measurements U and V were made by means of high-sensitivity moiré interferometry. The corresponding distributions of stresses, σ_x, σ_y, and τ_xy were determined for the free surface. Near the interface, and along its length, the largest stresses were σ_y, acting perpendicular to the interface. The σ_y peaks occurred very close to the interface, but not on it. These peak values were tensile in the steel and compressive in the brass. The transition between these opposite peak stresses featured an extremely strong gradient in a 50 µm interface zone. The distribution was akin to that of a stress singularity, but the stresses reached finite peak values in the physical experiment. Even larger stresses were found near the corner, where the interface of the two materials intersects the free edge. Both macroscopic and microscopic moiré interferometry were required to determine the stress distribution. / Ph. D.

Solutions of cellulose esters with different concentrations in dimethylacetamide (DMAc) and with different types of substituents were studied in relation to their liquid crystalline (LC) solution behavior. Classical LC behavior was revealed for all solutions. Critical polymer concentration (V_p^c) is highest for cellulose acetate (CA) and lowest for cellulose acetate butyrate (CAB) with highest degree of butyration. This is opposite to the classical model by Flory which predicts an increase in V_p^c with decreasing aspect ratio (L/d). Fibers were spun from isotropic and anisotropic DMAc solutions of cellulose esters by dry jet/wet spinning process. The mechanical properties, orientation, and crystallinity of the fibers increased as spinning progressed from the isotropic to the anisotropic solution state. High butyryl content enhances both overall solubility and the formation of LC solutions at lower concentration, but it results in lower fiber properties. Unmodified cellulose (C) and cellulose hexanoate (CH) also exhibited LC behavior. The V_p^c value for CH was lower than that obtained for CAB with maximum degree of butyration. This indicates that bulky substituents may lower V_p^c values. The formation of high modulus (152 g/d) cellulose fibers from LC solutions is attributed to the air-gap that exists in the dry jet/wet spinning process. Presence of lithium chloride (LiCl) in the LC solutions of CAB exhibited ionic interactions. Mechano-sorptive creep behavior of the fibers spun from these solutions decreases in the presence of residual LiCl salt. Fibers from blends of CAB and of C with lignin (L) were spun from Lc solution. Morphological investigations demonstrate that CAB and L formed intimately mixed blends whereas C and L were partially mixed. The mechanical properties of the fibers with L increased due to good phase mixing of CAB and L molecules in the fiber matrix. / Ph. D.

This study uses the tools of accounting research in an exploratory examination of American Depositary Receipts (ADRs). ADRs are registered certificates that represent specified amounts of foreign stocks held in trust by the banks issuing the ADRs. They are used to avoid the day-to-day problems created by international securities transactions. The empirical portion of this study considers three research areas linking ADRs and accounting. The first question considers whether ADR firms show financial accounting information that is characteristically different from that for non-ADR firms. The major conclusion is that corporate size is the predominant distinguishing factor. The second question is whether the portion of the periodic returns on ADR investments caused by foreign currency exchange effects is significant. The major conclusion to this section is that foreign exchange effects can significantly affect ADR returns, but not in a consistent manner. The third area examines whether ADR returns are more closely correlated with the American markets on which they trade or with the foreign markets on which their underlying shares trade. This portion of the study shows that every possible correlation combination exists among the sample ADRs. In addition to considering these empirical questions, this study includes a thorough historical investigation of the origin and evolution of the ADR as a financial instrument. / Ph. D.

The prevailing purpose of this dissertation is the preparation of an historical account of public schools in Roanoke County from 1870 to 1920. The primary focus rests with the cultural, economic, political, and geographic factors that affected the evolvement of public schools in Virginia relative to Roanoke County Public Schools, a system in southwest Virginia. Within this framework the system is described as part of a valley-wide setting, where citizens, educators, events, funding, curriculum, and other components played an integral part in the shaping of the current system. The methodology employed in this study is qualitative in approach and utilizes recognized historical and ethnographic techniques. The Guba model, which allows for periods of discovery followed by refinement and verification, is suited to the nature of this study. The researcher initially conducts inquiry designed to discover data and generate ideas. After the initial inquiry period, the researcher refines and corroborates data. The cycle of broad inquiry followed by more critical analyses of specific occurrences can repeat itself several times. Verification is accomplished through the validation of sources based on triangulation, a method of cross-checking in which three or more sources are used to corroborate findings. Data is collected in an eclectic fashion, using the nature of the research questions to determine appropriate techniques. Primary sources are used when available, supplemented by secondary sources. Outcomes have not been predetermined but evolved as the research progressed. General interview guidelines have been used, but remained felxible enough to allow for probing and expansion of relevant topics. It is anticipated that the history of Roanoke County Public School from 1870- 1920 will -provide an accounting of historical developments within this time frame; -enrich the legacy it leaves to future generations; -develop an appreciation for the obstacles and trials that people overcame; -create as accurate an interpretation as possible from available data; -develop a sense of the past as a precursor to the present; -provide an avenue for practical use of this knowledge in developing a better future plan; -provide an historical account of public school education in Roanoke County that has heretofore been meager; -contribute to a broader body of historical information on Roanoke County / Ed. D.

The purpose of this study was to examine the rate and reasons for turnover among Virginia elementary school principals over a five year period. Principals responded to a mailed questionnaire examining categories of continuing and departing principals and the factors that influenced their decisions. Personal and professional demographics, extrinsic and intrinsic factors found to be significant in previous mobility studies were compared to those cited by Virginia principals. The five year turnover rate was found to be consistent with earlier predictions, even with the impact of early retirement discounted. Factors contributing to turnover were pressure and stress, financial factors, work demands and factors beyond the principals' control. Although the same factors operate on all principals, departing principals appear to be more influenced by a combination of these factors than continuing principals, who may remain because they feel that they can continue to exert a positive influence. / Ed. D.

Data from 946 Angus and 351 Simmental females were used to quantify relationships between calfhood and early-life traits of females with fertility in the first two breeding seasons, and with calf production in the first, in three and in eleven years of life. These traits were used to develop prediction equations for fertility using logistic regression methodology. For productive performance, three methodologies were compared: least squares, ridge regression and principal components regression. For heifers of both breeds, fertility was associated with birth date, weaning weight ratio and weaning-yearling relative growth rate (RGR). The only calfhood trait that consistently affected fertility in the second breeding season was birth weight of the cow. Fertility of first parity Simmentals was also associated with birth-yearling RGR. First calving season traits explained a higher proportion of variation in second breeding season fertility than calfhood traits of the cow. Among these traits, calving date, calving ease score and sex of the calf were the most important. The combination of birth date and weaning-yearling RGR produced the best models to predict heifer fertility for both breeds. Fertility in the second breeding season was best predicted for Angus cows when calving date, calving ease score and sex of the calf were used as regressors. For Simmental cows, fertility in the second breeding season was best predicted from birth weight of the calf and calving ease score. The regression of weaning weight of the first calf on pre-selected calfhood traits was used to evaluate models produced by least squares, ridge regression and principal components regression. Although biased, the regression coefficient estimates produced by ridge and principal components regression had smaller variances than estimates obtained from least squares. Between the two alternatives to least squares, ridge regression produced better results than principal components regression. Ridge and least squares regression were quite similar in their regression coefficient estimates, in prediction sum of squares (PRESS)-like statistics and, to a lesser extent, in conceptual predictive criteria (C_p)-like statistics. For prediction, the performance of models produced by least squares and by ridge regression were very similar. For analyses of the production traits, least squares regression models for all possible combinations of pre-selected regressor variables were fit. Birth date of the female was negatively associated with the weaning weight of the first calf, and with number of calves weaned, total weaning weight of calves produced and average weaning weight of calves in the first three years of productive life. Age of the dam affected early-life production traits of daughters, as well as the average weaning weight of calves produced per year of productive life and calf survival in eleven years. Heavier females at birth tended to produce smaller number of calves and lower calf weaning weight through their lives than females lighter at birth. Overall female productivity was consistently more positively associated with yearling than with weaning growth traits. Among traits observed in the first calving season, calving date, calving ease score, sex and weaning weight of the calf were associated with subsequent production. Weaning weight of the first calf was always positively associated and it was the most important variable to predict female production, except for survival rate. Prediction equations for production in three years included birth date, birth weight of the female, calving ease in the first parturition, sex of the calf and weaning weight of the first calf. This latter variable was the only one useful to predict production in eleven years. Average calf weaning weights in the first three years of production were best predicted using yearling weight ratio or weaning-yearling ADG and first calf weaning weight. Models including age of the female’s dam best predicted weaning weight of calves per year of productive life in eleven years and calf survival. / Ph. D.