The present study investigated the extent to which movement time and practice influenced usage of feedback by subjects to make corrections in the spatial-temporal movement pattern of coincident timing responses. Twenty-four college males and females watched a .01 sec timer and attempted to knock over a barrier at the precise moment that the sweep hand reached a "target position" (250, 500, and 1000 msec). All subjects were given 100 trials of practice at a particular "target position" on each of four consecutive days. Schmidt's (1972) index of preprogramming was calculated for each subject each day in order to estimate the level of feedback involvement in controlling the movement, while the spatial-temporal pattern of the response was characterized by segmental movement time and variability. The results indicated that the index of preprogramming increased as instructed movement time decreased but remained stable throughout all trials. This suggests that movement time and not practice limits the extent to which a response is programmed, with rapid performance more likely to be pre-programmed than slower performance. Likewise, the spatial-temporal pattern of the movement was found to fluctuate as instructed movement time increased but remained stable over practice. Indeed, the 250 and 500 msec movements appeared to be primarily ballistic while the 1000 msec movement appeared to be adjusted in the terminal phase of the response by accelerating or decelerating the rate of movement. Thus, it was assumed that the index of preprogramming was sensitive to changes, as a result of feedback based corrections, in the spatial-temporal pattern of the movement. / Ph. D.

The purpose of this research was to study whether child-rearing attitudes would differ over time in three different classes in the Department of Management, Housing and Family Development, Virginia Polytechnic Institute and State University. These classes were Creative Expression of Young Children (Class I); Human Development I: Infancy Through Middle Childhood (Class II); and Introductory Household Equipment (Class III). A total of one hundred and twenty-two subjects were given both a pre- and a posttest using the Child-Rearing Attitude Scale developed by Block (1955). Information was gathered on subjects' age, sex, race, year in school, previous child-related courses, education and marital status of parents, and parent's child-rearing behavior. Using the t-test as the statistical method of analysis, results showed significant differences between pretest and posttest means for each individual class. Statistically significant differences were also found between the pretest and posttest means of Classes I and II and Classes I and III. However, when a correction was made for initial pretest differences, no further increase in mean differences on the posttest were found. A much higher percentage of subjects in Class I answered “yes” when asked if they had taken any previous child-related courses and reported having taken more of these courses than subjects in either Classes II or III. Results showed that Class I subjects had the lowest mean scores on the Child-Rearing Attitude Scale, which reflects more democratic, rather than authoritarian, child-rearing attributes. / M. S.

M.S.

The bacteriostatic or bactericidal action of metronidazole, clindamycin, tetracycline, chloramphenicol, cefoxitin and penicillin were determined against sixteen Bacteroides fragilis strains and six B. thetaiotaomicron strains. Drugs were considered bactericidal when minimal bactericidal concentration (MBC) to minimal inhibitory concentration (MIC) ratios were less than or equal to four. As expected, metronidazole, cefoxitin and penicillin were bactericidal. However, clindamycin and chloramphenicol, which other investigators have considered as bacteriostatic antibiotics, were bactericidal. Tetracycline was irregularly bactericidal. When tested against Escherichia coli, tetracycline and chloramphenicol were bacteriostatic as reported by others. The MBCs of metronidazole, clindamycin and tetracycline were well within the clinically achievable levels of each drug. Death rate data confirmed these findings. With tetracycline, chloramphenicol and metronidazole MICs and MBCs increased as inocula sizes increased, however, with clindamycin and cefoxitin only MBCs increased. Clindamycin was administered to mice which had pure B. fragilis abscesses. Over 8 h cell numbers in the pus remained relatively constant even though, during this same period, the concentration of clindamycin in the pus was above the MBC of this drug for the strain used. / M.S.

Throughout the history of public education in the United States religion has been an important factor in the schooling process. From the inception of public schools until the present time the Bible's inclusion is but one indication of the interrelationship of religion and education. The major legal questions that this relationship has raised have generally dealt with the First Amendment clauses dealing with the free exercise of religion and the separation of church and state. One major religious constituency, evangelical Christianity, in recent years has begun to vocalize its concern about this relationship. Evangelicals, although not necessarily wanting to return to the days of the Protestant public schools, do want this relationship corrected and articulated. One method of articulation is through effective public school policies. The major portion of this study specified the relationship between religion and public education and developed a framework for analysis from a historical, evangelical and public policy perspective. A descriptive study was then made of Virginia's public school policies that dealt with religion. A questionnaire, developed by the author, was submitted to all the local school divisions in the state to solicit a policy and information about that policy. Conclusions, recommendations and implications were stated based upon the information provided in the study. Proposed public school policies on religion for local and state school boards were provided as a prescription for partial solution to the problem of the correct relationship between religion and public education. / Ph. D.

The central problem of this study was to identify and compare the basic sex bias beliefs of (1) male and female postsecondary occupational educators; (2) post-secondary occupational educators teaching in male-oriented, nonsex-oriented, and female-oriented programs; and (3) postsecondary occupational educators teaching in small, medium, and large campuses. A secondary problem was to determine (1) if there was a relationship between the biographical variables (sex, age, educational level [highest degree earned], years of teaching experience, and years of occupational experience) and the identified basic sex bias beliefs of post-secondary occupational educators; and (2) if there were differences in the identified basic sex bias beliefs of postsecondary occupational educators who teach in programs of varying sex orientation (male-oriented, nonsex-oriented, and female-oriented) and who teach in campuses of varying sizes (small, medium, and large). The research procedures used in this study consisted of five steps. These steps were: (1) reviewing the literature for basic sex bias beliefs; (2) developing, validating, and pilot testing the instrument; (3) collecting data; (4) analyzing the data; and (5) interpreting and reporting the data. The instrument used to collect data was developed in a scale format by the researcher, and contains a total of 30 items. Eleven of these items measure general sex bias and 19 measure same sex bias/opposite sex bias. A random sample of postsecondary occupational educators (417) from USOE Region Three (Delaware, Maryland, Pennsylvania, Virginia, West Virginia, and the District of Columbia) were potential respondents in this study. The analysis of data consisted of (1) descriptive statistics to provide a respondent profile; (2) descriptive statistics to identify and compare the basic beliefs; and (3) statistical tests of the research questions (Multivariate Analysis of Variance and Pearson correlations). / Ed. D.

Ed. D.

Study of two streams impacted by surface-mining and a similar unimpacted reference stream demonstrated that alkalinity, conductivity, hardness, and sulfate were elevated in the former despite reclamation treatment of the watersheds three to five years earlier. The mined-watershed streams carried a heavy benthic sediment burden, due primarily to the continued erosion from the mined areas and from abandoned haul roads. Inorganic sediment in the mining-impacted streams covered the natural rubble substrate, smoothing the bottom, filling in pools, and impacting the processing of allochthonous organic material, the principal energy source. Fine-particle organic material was trapped in the sediment, but density of larger particles was reduced, possibly due to increased transport over the smoothed substrate. Benthic invertebrate and fish density, biomass, and diversity were consistently lower in the mining-impacted streams. The pattern of fish and benthic invertebrate recovery following a major flood was slow but unique in all streams. The benthic and fish communities of headwater streams are naturally subject to decimation by flooding, but sediment-mediated habitat and food degradation may further limit invertebrate and fish populations in disturbed systems. This study demonstrates that sedimentation can be a severe and long-term after-effect of surface mining, even in the absence of acid drainage. Terrestrial reclamation did not result in lotic reclamation and recovery. The inclusion of water quality criteria in the administration of mined-land reclamation would promote terrestrial management practices conducive to aquatic systems recovery. / Ph. D.

This study was an investigation of the relationship between landscape preference and looking time. In the Original Experiment 100 subjects were unknowingly timed while looking at 10 slides of natural landscapes. They then ranked photographic representations of those slides for their preference of them as scenic vistas. A random sample of 25 of the original subjects participated in a Follow-up Experiment about one month later in which they ranked the same landscape simulations as in the first experiment. The analysis of data was divided into two main aspects. In the first aspect the relationship between looking time and preference rank in the Original Experiment was analyzed through summary statistics, frequency distributions, and correlations. In addition, a test to point out the relationship among the average looking times for the slides computed. The second main aspect was an. investigation of the agreement between the rankings in the Original and Follow-up Experiments for the purpose of determining the reliability of the sample subjects’ preferences for the landscapes used as visual stimuli. The major results of this investigation included: (a) the average time spent looking for all the slides was 7.02 seconds, (b) looking-time frequencies varied greatly with the majority of the 100 subjects looking at each slide for approximately 2 to 11 seconds, (c) the overall estimate of correlation between looking time and landscape preference was r = -.073, and (d) of the 25 sample subjects only 2 ranked at least half of the slides (5) in the Follow-up Experiment exactly the same as they did in the Original Experiment; however, the overall estimate of correlation between the two rankings was calculated to be t = .606 (significant at p≤.0001). The investigator concluded that (a) there appears to be no relationship between looking time and preference rank for natural landscapes, (b) there was very little variability among the average looking times for the slides by all the subjects, a range of 6.58 seconds to 7.75 seconds, (c) the subjects’ preference rankings generally ranged across all the integer value ranks for each slide, (d) for all slides except one (I) no integer value for preference rank had a dominate frequency, (e) preference ranking, as was determined by comparing sample subjects’ rankings in the Original and Follow-up Experiments, is a reliable direct method for determining landscape preference, (f) landscape complexity may be a major indicator for determining variation in looking time, and (g) subjects may unconsciously lapse into a rhythmic time-sequence pattern when operating a slide projector. / Ed. D.

The goal of this dissertation is to investigate the feasibility of using a bivariate Chebyshev polynomial to approximate solutions to the two-dimensional neutron diffusion equation. The two-dimensional two-group neutron diffusion equations are solved by expanding neutron fluxes in a finite series of Chebyshev polynomials over large regions of a fission reactor. All the equations for the expansion coefficients necessary to satisfy the appropriate boundary conditions for the flux and current for a typical region are developed. The resulting system of algebraic equations is solved, using the power iteration method. Since the system of equations is overdetermined, the Gram-Schmidt method of orthogonalization is used. Calculations are done with the aid of a computer code, CDP, developed as part of this dissertation. Two different test problems are solved using a first order finite difference computer code, PDQ-7 as a standard for comparison, and CDP. The first problem is a water-reflected square core with homogeneous material properties in each region. This problem is selected to provide a rather severe test of the CDP method in the calculation of large thermal neutron flux peaking at the core- reflector interface. The second problem is an actual problem solved by a utility for on-line-fuel management in a Pressurized Water Reactor. The reactor core consists of four-different fuel assemblies arranged in a checkerboard pattern in the interior of the core. For the first problem, both PDQ-7 and CDP give about the same fast neutron flux distributions. The eigenvalues calculated by both methods are identical to one part in 4800. Except for a small region near the core-reflector interface, the thermal neutron fluxes within the core differ by less than about 4%. At the core-reflector interface, the difference in thermal fluxes is about 20%. A significant reduction in computer time required for the solution is achieved (0.45 sec for CDP vs 32.6 sec for PDQ-7). It is important to note, however, that the time required to obtain the "standard" solution for comparison, using PDQ-7 is larger than would be needed for a large mesh spacing. Thus, the savings in computer time required to achieve a solution using a PDQ-7 type code giving results comparable to those obtained with the CDP code cannot be inferred directly from these results. In any event, note that the CDP method is indeed. economical in both preparation of input data and computer time. In the second problem, four very large regions are used in the CDP method for the entire reactor. These regions are much larger than those used in a typical finite difference solution for the same problem. Both methods give about the same fast neutron flux distribution. The eigenvalues calculated by the two methods are identical to one part in 2140. Although the CDP method does not show the assembly-to-assembly variation in thermal neutron flux, it gives the Same average thermal neutron flux as calculated with PDQ-7 to within 2%, except near the core boundary. Again, a large reduction in computer time is achieved (0.69 sec vs 101 sec). The feasibility of using Chebyshev polynomial expansions for two-dimensional multi-group diffusion calculations has been demonstrated for these two problems. The method gives, not only very accurate eigenvalues, but also reasonably accurate neutron flux distributions within the reactor core. / Ph. D.