Entocytherid ostracods were collected on crayfishes inhabiting the James and York River basins of Virginia. Of the seventeen species encountered, only one (Donnaldsoncythere ardis) seems to be endemic. Ankylocythere ancyla, Dactylocythere banana, Dt. falcata, Dt. suteri, Donnaldsoncythere ardis, Dn. hiwasseensis, Dn. truncata, Entocythere sp. A, E. internotalus and Phymocythere phyma occur on the crayfishes Cambarus acuminatus, C. b. bartonii, C. longulus and Orconectes juvenilis in the streams of the Valley and Ridge Province. In the Coastal Plain where sluggish streams are encountered, Ankylocythere telmoecea and Ank. tiphophila are associated with Procambarus a. acutus. Cambarus acuminatus is also found in the Coastal Plain in moderately flowing streams and it is infested with Dactylocythere suteri and Donnaldsoncythere hiwasseensis. The primary burrowing crayfish of the Alleghany Mountains (Cambarus dubius) is host to Ascetocythere asceta and Dactylocythere chalaza whereas its ecological similar Cambarus d. diogenes of the Piedmont and Coastal Plain is the only host known with certainty for Dactylocythere jeanae, Okriocythere cheia and Ornithocythere waltonae. Ankylocythere tiphophila is associated with Fallicambarus uhleri, an inhabitant of swampy areas and marshes and may ocassionally construct simple burrows in the Coastal Plain. / Master of Science

The 1972 amendments to the Federal Water Pollution Control Act provide for major changes to reduce and eventually eliminate water pollution by 1985. In contrast, projections indicate that the volume of wastes generated by population and economic growth in the near future will be very large and the cost of treating it by standard methods will be extremely high. Hence, all possible systems and methods of waste disposal must be considered and ways of reducing the amount of waste discharges sought. In attempting to reach the goal of zero waste discharges, one alternative which must be considered in certain situations is the employment of deep well waste disposal (DWWD). This method accomplishes long term isolation of highly toxic liquid industrial wastes in confined subsurface geologic strata. This study undertakes a preliminary investigation of the potential of DWWD as a waste management tool. The analysis is conducted from an economic standpoint with the relevant economic concepts and issues being identified and examined as they apply to both users and regulators of the method as well as the general public. The direct cost for the system and its operation was discussed with particular attention paid to its derivation. Numerous site specific variables prevent generalizations concerning the cost of DWWD relative to surface treatment methods. On occasions, however, the method appears to have a greater initial capital outlay requirement but a much less operating and maintenance cost than alternative forms of wastewater management achieving the same effect. The social costs and benefits of deep well waste disposal were viewed in detail. Suggestions were made as how society might compensate the firm for the creation of social benefits in excess of social costs, and how they may be internalized into the firm's decision making process. Finally, the industrial potential for employing DWWD in the study area, designated as the Mid and South Atlantic states, is derived and discussed. / Master of Science

In this thesis the applicability of a hospital patient flow model is used in addressing hospital resource allocation problems. Three separate but interrelated models are presented. First, the hospital patient flow model is discussed. The main feature of the hospital patient flow model is the matrix of technical coefficients, which gives the probability of patient transfers throughout the hospital. Given the hospital system's daily patient input, the model provides the patient demands upon the different hospital services. Results from the patient flow model are used in the development of a staff allocation model. The staffing model involves the minimization of a weighted quadratic penalty function. The weighting factors are based on the proportion of patients in each of three carelevels in the wards. The weights are also dependent upon whether overstaffing or understaffing is the situation. Constraints to the model include a desirable mix and number of the available nursing staff. Solution of the allocation model is obtained by using SUMT with a pattern search. A third model concerned with predicting hospital revenues is presented. Again, results from the hospital patient flow model are used to present estimates of the expected values and variance of a hospital's revenue. To illustrate the use of the models, results from a two-week study period of the Montgomery County Hospital are presented and discussed. / Master of Science

The objective of this thesis is to develop and implement a power systems analysis package for use on minicomputers and programmable calculators. Algorithms for four different load flow techniques are developed and tested on the HP9830A programmable calculator. The transient stability analysis problem is reviewed, with special attention being given to the solution of the system performance equations by either the bus impedance matrix approach or the bus admittance matrix approach. Also attention is focused on the solution of the machine swing equations by the state transition method and by the technique of fourth-order Runge-Kutta. Comparisons are made between the different load flow methods to possibly determine the 'best' method to be used in the analysis package. Comparisons are also made between the methods of solving the swing equations in order to select a preferred technique for use in the stability program. / Master of Science

This research investigated the effects of age, sex, male vs female voice, and unfamiliar vs familiar voice upon the infants body movements. The sample consisted of 40 middle-class infants, balanced according to sex, at four age levels -- 3, 6, 9, 12 months. Four tape-recorded stimulus conditions -- mother's voice, father's voice, female stranger’s voice, and male stranger's voice -- were presented to each infant. The body movements of the infants were recorded at one frame per second by an 8mm. camera. Analyses of variance were performed to determine any differences among the four stimulus conditions and control periods. The 12-month-old infants showed more activity to the father's voice than to the male stranger's voice or to the mother's voice. These subjects also showed more activity to the female stranger's voice than to the male stranger's voice. Female subjects were more active than male subjects to the unfamiliar voices on Trial 1. On Trial 2 females showed greater activity than males to the familiar voice. Females exhibited greater activity than males overall. Males showed greater activity than females to the cessation of the female voice and to the initiation of their father's voice. Results were discussed in terms of the infant's development as affected by sex of the infant and the cross-over effect found by Friedlander (1970). / Master of Science

Video tape records were made of seventy-seven infants, ranging in age from one to 24 months, as each was exposed for three minutes to four different levels of mirror distortion. A mirror behavior checklist (Amsterdam 1968, 1972) was used to identify 34 possible behaviors. The range and complexity of mirror related activities increases significantly during the first two years of life, culminating in self-recognition by 52% of the subjects aged 19 to 24 months. All subjects responded equivalently to both the plain and distorted mirror images, suggesting that it is the general configuration of the face that holds intrinsic interest at these age levels. The prevailing view that the infant's perception is qualitatively similar to that of the adult was supported by this study. / Master of Science

Ph. D.

A digital model reference scheme is presented for the control of the longitudinal modes of an EBF-STOL aircraft. The method used is based on Liapunov's direct method and is used to update feedback and feedthrough matrices. An equilibrium point of the EBF-STOL is chosen about which to constrain performance to follow that of a linearized decoupled DC-9 model. The change of control matrix elements is controlled by (1) an error vector equal to the difference between state variables of the model and those of the STOL, (2) the present values of the pilot inputs and STOL state variables, (3) a P matrix obtained from the equation A_mᵀPA_m - P = - I where z(k + 1) = A_m z(k) + B_m u_p is the equation of motion for the model, (4) selected gains, and (5) a matrix B₋ᵤʳ⁻¹ whose elements are determined by the inverse of an n x n partition of the linearized input matrix B₋ᵤ of the STOL. A method for smoothing control action is discussed. / Master of Science

Duodenal, jejunal and ileal sections from sheep were used to study <i>in vitro</i> absorption of valine, threonine and methionine. Everted sacs were incubated for 45 minutes at 39 C under an atmosphere of 95% O₂ - 5% CO₂ in Krebs-Ringer bicarbonate buffer (mucosal and serosal fluid) containing 5 μmoles per ml of the test amino acid. The hydrolyzed tissue and mucosal and serosal fluids were analyzed for amino acid content. The duodenum absorbed smaller quantities of amino acids from the mucosal fluid than the jejunum and significantly (P<.01) less than the ileum. The release of amino acids from duodenal tissue was small for threonine and methionine and negative for valine. Accumulation of amino acids by duodenal tissue was not significantly different from the ileum, but this represented a larger part of the amount absorbed from the mucosal fluid. The duodenum appears to be of limited importance as a site of amino acid absorption. The jejunum readily absorbed valine and methionine, but absorbed only a small amount of threonine from the mucosal fluid. The release of amino acids into the serosal fluid by the jejunum was very slight in comparison to the ileum (P<.01). Tissue accumulation of amino acids was significantly less (P<.05) than in either the duodenum or ileum. While the jejunum generally absorbed large amounts of amino acids from the mucosal fluid, it did not release or accumulate amino acids in large amounts. The ileum maximized movement of all amino acids. It absorbed significantly more (P<.01) amino acids from the mucosal fluid and released significantly more (P<.01) amino acids into the serosal fluid. The accumulation of valine and threonine by ileal tissue was significantly greater (P<.05) than the jejunum. The ileum, therefore, appears to be the most active and efficient site of valine, threonine and methionine absorption in the sheep. / Master of Science

An experimental comparison has been made of the behavior of thermal effluents released by two different basic discharge methods. First, a multiple port diffuser, which acts to enhance mixing of the discharge with the receiving, water, was studied. Second, a single jet discharge, which is simpler, but achieves less rapid dispersion and dilution, was investigated for discharge at the surface and submerged. The study consisted of three experimental phases. First, dye tests were conducted and photographs of the dyed, heated discharges were taken to record flow patterns. Second, the temperature field in the receiving stream was measured with thermocouple probes. Third, thermographic color patterns were developed with sheets of liquid crystals, and photographed in color. The results showed that the multiple port diffuser minimized temperature gradients in the receiving stream, but resulted in greater heat storage within the stream. Also, the single jet located at the water surface, tended to maximize temperature gradients, but allowed better heat dissipation to the atmosphere. / Master of Science