This study derives a theoretical basis for planning forest regeneration operations and forest regeneration research projects. The purpose of such planning, is to facilitate effective implementation and monitoring of projects so that the forest investment goals of the finn may most easily be met. After discussing three approaches to problem solving, a production economic theory model is developed to derive the optimum production relationships. Regeneration strategies are defined as plans aimed at achieving these optimum results. A concept of regeneration research strategies is limited by the perfect certainty assumption of the model. Due to the uncertain nature of future events and the long period of forest production, the perfect certainty restriction is abandoned. Several methods for dealing with risk are discussed, including expected value, risk-adjusted discount rates, certainty equivalents, and risk measurement. A Markowitz efficient risk-return investment frontier is illustrated. Optimal investment strategies are those which maximize the firms risk-return utility preference subject to the efficient investments frontier. The scope of regeneration and regeneration research strategies is expanded and illustrated through use of the risk-return model. Regeneration strategies are plans aimed at making the highest return from forest production subject to the firms risk-return preferences. Regeneration research strategies are employed to select the optimum methods of research and optimum project selection. Regeneration research should be aimed at increasing the forest production function, learning more about the production relationships, and reducing the risks of production. / Master of Science

The machine requirements planning problem is one which is applicable throughout the manufacturing industry. The use of automation and computer technology makes the use of machine requirements modelling particularly attractive, and the vast capital investment in machining equipment offers significant opportunity for savings through optimization. The machine requirements problem must be modelled as a mixed integer linear program. However, a dynamic programming solution procedure with linear programming postoptimality techniques at each stage of the machining process is utilized to provide an efficient, flexible algorithm. The machine requirements model is capable of optimizing any type of machining system, whether of a discrete or continuous operating mode. Through discretizing the machine parameters problem, by limiting tool changes to between passes of a tool, any continuous mode system is approximated as discrete for optimization purposes and a direct interface with the machine requirements planning model is provided. The dynamic programming solution procedure is compared with a mixed integer procedure. The DP formulation is not only more efficient in both time and core but provides sensitivity information and offers a broad spectrum of further application into more complex aspects of manufacturing systems. / Master of Science

The present information processing research provided a comparison of visual search and memory search processes with respect to search rates and search strategies. An innovative paradigm was evaluated which varied search type (i.e., visual or memory) randomly between trials of a single choice reaction time (RT) task. The following sequence of events for each of the 280 trials occurred. A ''memory" list of letters appeared, which subjects (N = 12) turned off by pulling simultaneously a left and right-hand RT trigger. After 3 sec, a warning buzzer sounded followed by a variable interval ranging from .5 to 1 sec and the "recognition" list. The subject pulled the left or right-hadn trigger as quickly as possible to indicate whether the memory and recognition lists included the same letter. A single target letter appeared as the memory list on the 140 visual search trials and as the recognition list for the 140 memory search trials. The search set (presented either as a memory list or recognition list) contained three, five, or seven letters. Memory Search was faster and less accurate than was Visual Search in the present task, The RT slope and serial position data indicated that Visual Search involved a serial, self-terminating comparison process, whereas the Memory Search data confirmed Sternberg's serial, exhaustive model. It was noted that physical characteristics of the task could have biased Visual Search toward a self-terminating strategy. Suggestions for future research in this area were discussed, as well as the author's plans to apply the paradigm to the study of information processing deficits in learning disabled children. / Master of Science

A serologic survey at Fort Pickett, Virginia was undertaken to determine if tularemia could be a factor in the continued low hunter harvest of cottontail rabbits. Between December 1976 and February 1978, ninety serum samples were collected from 11 species of mammals and 1 avian species, and tested for antibodies against Francisella tularensis. Evidence of infection was found in 5 raccoons, 3 opossums, 1 striped skunk, 1 Norway rat, 1 chipmunk, 1 white-tailed deer, and 1 bobwhite quail. This indicated that tularemia was present at Fort Pickett in a number of species and could be responsible for the low numbers of cottontails present. As the result of an epizootic of cerebrospinal nematodiasis among rabbits caused by Baylisascaris procyonis, a survey of the presence of B. procyonis in its definitive host was undertaken. Between December 1976 and February 1978, 72 raccoons from 11 counties were examined. B. procyonis was found in raccoons from Augusta, Carroll, and Montgomery Counties. It was not found in any raccoons collected from the 6 counties east of the Blue Ridge. This indicates that B. procyonis may only be a cottontail regulatory factor west of the Blue Ridge Mountains. A final phase of the study was to determine the effects of parasitism and nutritive restriction. In a 2x2 factorial design experiment 19 cottontails were placed on an ad libitum or 70 percent ad libitum diet and treated with Atgard^R, an anthelmintic, or untreated control. It was found that Trichostrongylus spp. were the only parasites significantly affected by drug treatment. The animals on the 70 percent ad libitum diet had lower final body weights, carcass weights, liver weights, tibia and femur marrow fat levels, and lower abdominal fat indices. It was concluded that the parasite loads were too light to significantly affect the host. / Master of Science

The nature of data acquisition in a realtime millimeter wave experiment is discussed. Goals for a data reduction system are presented and the available processing environment analyzed. Some currently popular software design methodologies are then reviewed and selectively applied to a complete system design based on modern database methods. / Master of Science

The purpose of this study was to assess the effect of temperature on the sensitivity of mixed age adult Daphnia pulex to a simulated cooling tower blowdown and a simulated refinery effluent. In addition, the metabolic rate compensation capability of Daphnia exposed to temperature was determined. An artificial refinery mixture (ARM) simulated the 1977 guidelines promulgated by EPA. Components of the ARM in mg were: ammonia (10), chromium (0.25), oil (10), phenol (0.1), sulfide (0.17) and suspended solids (20). Components of the simulated blowdown mixture (SBM) in mg 𝓁⁻¹ were: zinc (2), phosphate (25), chromate (15), sulfate (824) and boron (0.5). After 72 hours at 20 C and 120 hours at 10 C, the median apparent threshold LC50s of the SBM were 0.045 at 10 C and 0.026 at 20 C. Similarly, threshold LC50s of the ARM were 0.106 at 10 C and 0.016 at 20 C. Mixed age adult Daphnia were pre-exposed to sublethal levels (LC10) of the SBM and the ARM at both 10 and 20 C and then subjected to t's above ambient of 5.4, 8 and 12 C for one hour. One other group received sublethal exposure only and the controls were maintained only in dilution water. After exposure survival and the number of viable and nonviable young were assessed. Daphnia pre-exposed to both simulated effluents and short-term thermal shock had significantly more nonviable eggs and young. Survival of 20 C Daphnia pre-exposed to both simulated effluents and subjected to a 12 C thermal shock was significantly reduced. Reproductively immature Daphnia showed a noncompensatory temperature acclimation pattern. Several hypotheses were presented to explain the adaptive nature of the noncompensatory pattern observed. / Master of Science

The loss of organisms to cooling water intakes has been identified as having an impact on aquatic biota. Impingement and entrainment of organisms are unavoidable if natural waters are to be used by utilities for cooling water purposes. This study was initiated to determine the effects of operation of the intake of the Glen Lyn Power Station on the fish community of the New River, Glen Lyn, Virginia. Estimates of the numbers of fishes impinged by the Glen Lyn Power Station were made for the period mid-May 1976 through May 1977. The estimated total impingement was 6219 fish of 22 species. The alewife (Alosa pseudoharengus) accounted for 86.6% of the fish; most of these were impinged during the winter probably as a result of cold induced mortality in an upstream reservoir population. The estimated numbers of other species impinged ranged from 6 to 182. Most of the fish were dead prior to impingement. An estimated 30,200,000 larval fish of an estimated 172,000,000 that drifted by the Glen Lyn Power Station during June 1976 through May 1977 were entrained by the power station. Larvae of the carp (Cyprinus carpio) accounted for 94.8% of the ichthyoplankton drift. Estimates of 14.5 to 21.7% of the larvae of selected representative species that drifted by the power station were entrained. The criteria listed by the United States Environmental Protection Agency for assessing the impact of intake operation on aquatic communities were used in conjunction with collected data and information on the fish community of the New River available in the literature. It was concluded that the losses to the intake of the Glen Lyn Power Station were not significant enough to affect the fish community structure of the New River near Glen Lyn, Virginia in its present condition. / Master of Science

A laboratory study was conducted to compare the coliform recovery capabilities of two membrane filter techniques on coliforms exposed to varying chlorine residuals and contact times. An enrichment-step membrane-filter method (E-MF) involved the incubation of a filtered water sample on lauryl tryptose plus 1.5 per cent agar for two hours at 35°C prior to transfer of the filter to LES-Endo agar and a final incubation for 22 hours at 35°C. A single incubation of the membrane filter for 24 hours at 35°C was employed in a non-enrichment membrane filter method (NE-MF). A free chlorine residual was established in a synthetic test water at a neutral pH and constant temperature prior to inoculation of the water from a suspension of bacteria comprised of four coliform genera commonly found in natural waters. Timed samples from 5 seconds to 15 minutes, analyzed for coliform recovery by the E-MF and NE-MF methods revealed an average increase in recovery of the E-MF to NE-MF method of 1.6:1. When the initial inoculum was kept below 1 x 10⁴ cells/100 ml, and the test water was chlorine demand- free no coliforms were recovered by either method after two minutes of contact time with free chlorine residuals greater than 0.12 mg/l. Many of the recovered colonies failed to produce a characteristic sheen but were verified as coliforms. It was concluded that all coliforms were effectively killed at chlorine contact times greater than two minutes and free chlorine residuals greater than 0.13 mg/l, in chlorine demand-free water. Free chlorine residuals of 1.0 mg/l effectively killed all coliforms within five seconds. / Master of Science

Two series of trials were conducted for five weeks to compare the performance of three to four week weaned pigs reared in single, double and triple deck pens. In these trials, the addition to a starter diet of a flavor compound previously fed in the lactation diet was evaluated as a means of stimulating postweaning performance. In the first series, two trials were conducted using 128 pigs each from sows fed flavor and non-flavor lactation diets. Pigs were reared in single, bottom and top deck pens. All pigs were fed flavor starter diets ad libitum. The combined data showed no significant differences in average daily gain, feed consumption and feed per gain between pigs reared in the various decks. Also performance was similar for pigs from the two sow groups. In the second series, three trials were conducted using 48 pigs each from sows fed flavor and non-flavor lactation diets. Half of the pigs from each of the sow groups was fed flavor starter diet and half was fed non-flavor starter diet. Pigs were reared on bottom, middle and top decks of a triple deck system. The combined data revealed no significant differences between pigs reared on the various decks. Also performance was similar for pigs fed flavor and non-flavor diets regardless of whether pigs were from sows fed flavor or non-flavor diets. In this study the double and triple deck systems increased nursery densities by 67 and 200%, respectively. The.use of the flavor compound in the sow lactation and pig starter diet did not improve performance. / Master of Science

Bird utilization of twenty fields was observed at monthly intervals for one year, from May 1977 to April 1978. The 20 fields were located in 2 areas of southeastern Virginia. A total of 30 bird species were observed using the fields. The migratory and movement patterns of some of the species were determined from bird banding data. A small proportion of 6 species recovered in the study area were originally banded to the south of the study area. Fecal material, soil from feet and crop contents were taken from several bird species collected in the field and analysed for Cylindrocladium crotalariae. Soil samples from a blackbird roost in the area were also analysed for C. crotalariae. None of the samples taken showed presence of the fungus. Microsclerotia of the fungus were force fed by different methods to 3 species of captive bird (Canada Geese, Japanese Quail, Bobwhite Quail) to determine viability after passage through the gastrointestinal tract. No viable microsclerotia were detected in fecal material taken from birds force fed loose microsclerotia. A very small number (a total of 5 of 10,000 microsclerotia from 2 geese) proved to be viable after passage through Canadian Geese after being force fed microsclerotia in porous bags. / Master of Science