Browsing by Author "Paterson, Robert A."

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    An analysis of palustrine forested wetland compensation effectiveness in Virginia
    Atkinson, Robert B. (Virginia Tech, 1991-09-03)
    Plans to construct a wetland to replace wetland losses has become a common feature of permit requests. The purpose of this project is to suggest a methodology for quantifying the effectiveness of palustrine forested wetland construction in Virginia. Wetlands constructed by ~ne Virginia Department of Transportation and the U.S. Army Corps of Engineers were surveyed and Wagner Road constructed wetland in Petersburg, Virginia was selected as the primary study site. Chapter One of the present study suggests a method for early assessment of revegetation success utilizing weighted averages of colonizing vegetation. An adjacent reference site was chosen that was in close proximity to the constructed site and was used for comparison. Results from the Wagner Road site and the reference wetland indicated that colonizing vegetation weighted averages provide a more sensitive measure of revegetation success than the methods described in the federal wetland delineation manual.
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    Aquatic fungi in rivers, their distribution and response to pollutants
    Farr, David F.; Paterson, Robert A. (Water Resources Research Center, Virginia Polytechnic Institute and State University, 1974)
    Two lotic habitats in the vicinity of Blacksburg, Virginia were selected for field investigations. The New River represented a river with a high nutrient load. Little Stony Creek, a tributary of the New River, has no sources of man-made effluent which might contribute nutrients to the stream. Collecting sites on the New River were located above, just below, and some distance farther downstream from the effluent outfall of a munitions plant. The effect of this effluent on the number of taxa was not conspicuous. However, there was a reduction in the number of taxa per collection at the station near the effluent when compared with the other stations. Filamentous aquatic Phycomycetes such as Achlya, Sapro/egnia, and Pythium were commonly found in both habitats. However, a greater diversity of the chytrid type of aquatic Phycomycete was found in Little Stony Creek as compared to the New River. Twelve chytrid taxa were found in Little Stony Creek and two in the New River. Two fungi, Achlya caroliniana from the New River and Rhizidium sp. from Little Stony Creek, were studied in pure culture in terms of the effect of common pollutants on their growth and reproduction. The A. caroliniana had higher tolerances to zinc, cyanide, and mannitol as compared to the Rhizidium sp. The Rhizidium was more tolerant to higher concentrations of detergents than the Achlya.
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    Biological and chemical monitoring of three streams in the area of Blacksburg, Virginia
    Hayles, Virginia Mosby (Virginia Tech, 1973-03-15)
    This study compares the sensitivity of biological and chemical parameters for monitoring water quality, examines several methods of analyzing diversity of the aquatic organisms and attempts to assess water quality in the three streams investigated. The Cairns-Dickson DIT diversity index was applied to two trophic levels of aquatic organisms and the results were compared to ascertain whether this diversity index is applicable to all levels of the trophic\structure or of greater use for a particular level. Two diversity indices, Cairns-Dickson DIT and Wilhm-Dorris d̅, were used to analyze the same component of the biological community and the results of these two indices were compared. A correlation test was performed among chemical and biological data and among chemical parameters.
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    Chromosome identification and analysis in selected lines of laboratory mice
    Schmitt, Athanasia Nancy Panos (Virginia Tech, 1976-06-05)
    Chromosome preparations from 102 ICR albino mice were examined using a modified trypsin Giemsa staining technique. The mice were from four lines selected for maximum rate of post-weaning gain (28 generations), one line selected for minimum rate of post-weaning gain (25 generations), and two unselected control lines. Mitotic metaphase chromosome preparations were obtained from bone marrow cells of adult male and female mice. Two similar treatments were utilized in obtaining the chromosome preparations. The first treatment consisted of: 50 minute colchicine pretreatment, 30 minute hypotionic pretreatment, four-glacial acetic acid-methnanol fixation periods, 15 second trypsin period and 15 minute Giemsa staining period. The second treatment varied from the first, basically, in the length of hypotonic pretreatment, and length and number of fixation periods. A mean number of 40 telocentric chromosomes with very similar banding patterns was observed in all lines. Relative chromosome lengths for each chromosome were obtained. The lengths for the various lines, control, high and low, were compared by means of a pooled "t" test. Non-significant a₂ levels were obtained for the pairwise comparisons of the lines. Significant a₂ levels were obtained for the effects of the two treatments, trypsin and no trypsin. Karyotypes for each line were made with no chromosomal abnormalities detected in any of the lines. The selection regime followed has produced significant genetic change in several characteristics of these mice. However, these changes have apparently not been accompanied by observable alterations at the chromosomal level.
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    Conceptualizing technological change: technology transfer in the green revolution
    Parayil, Govindan (Virginia Tech, 1990)
    Technological change, and technology transfer as an aspect of this process, is examined by providing a comparative assessment of models of this phenomenon from economics, history, sociology, and neo-Schumpeterian-evolutionary studies. The Green Revolution, which is used as the empirical basis for testing these models, is generally referred to as the change in agricultural technology observed in some Third World countries in the 1960s and 70s as a result of the transfer of high-yielding varieties (HYVs) of seeds and a new culture of agricultural practice resulting in high productivity of the land. It is found that most of the examined models of technological change do not completely account for this process. It is argued that technological change should be conceptualized as a process of knowledge change. Artifactual change, which the examined models accentuate, should be viewed as the manifestation of the knowledge change at a secondary level. With the Green Revolution as the empirical basis, arguments are presented for a comprehensive model of technological change within the framework of "technology as knowledge."
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    Development of defined media for motility and for growth of Spirillum volutans, with special reference to biological monitoring of pollutants and to obligate microaerophilism of bacteria
    Bowdre, Jean Handy (Virginia Tech, 1975-05-05)
    Two investigations were pursued in this study. One was a possible application of the motility of Spirillum volutans to detection of pollutants in industrial effluent for the purpose of in-plant biological monitoring. The other was a nutritional study of the organism with emphasis on its obligate microaerophilism. In the pollution monitoring project, flagellar uncoordination in S. volutans was studied as a bioindicator of toxicity. Uncoordination is produced by a variety of agents. Cells displaying normal motility show frequent reversal of direction, accompanied by reversal of orientation of their bipolar fascicles of flagella. In uncoordinated cells, the flagella at opposite poles oppose each other and the cell cannot swim, although the flagella remain active. A defined motility test medium was devised in an attempt to maximize the sensitivity of the uncoordination response to potential pollutants. Suspensions of S. volutans in this medium responded to a variety of agents, including metal ions (1-3 ppm), cetyl pyridinium chloride (1 ppm), hydrazine (10 ppm), i-naphthol (3 ppm), and others. Effective concentrations ranged up to several per cent for the alcohols tested. The response was immediate.
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    Distributional analysis of the freshwater mussel fauna of the Tennessee River system, with special reference to possible limiting effects of siltation
    Dennis, Sally D. (Virginia Polytechnic Institute and State University, 1984)
    Mussel studies in the Tennessee River drainage (1973 - 1982) examined ecology and distribution and investigated factors limiting to distribution. This river system presently supports 71 freshwater mussel species, 25% of which are endemic to the Cumberlandian Region. Species have been extirpated from this drainage within the past 60 years, however the number of extant species remains high. The major impact of man's activities has been reduction of available habitat. Past and present distribution records indicate that mussel species assemblages are determined by geologic history and stream size. Although some overlap of species exists among stream size categories, there is no longer a continuous gradation from one category to the next; mussels exist in isolated communities separated by nonproductive river reaches. Productive reaches supporting more than 60 mussel species once existed in habitats spanning the transition from medium to large rivers; reaches now altered by impoundment. The maximum number of species reported in recent collections from any one site in the Tennessee drainage is less than 40, which seems to be the maximum number of species niches available. Quantitative sampling reveals characteristic patterns of species dominance. Changes in species dominance and age class structure provide a better basis for evaluating changes over time than do species composition or diversity alone. Mussel density was found to be more variable than species composition, and was unrelated to species abundance. Experiments on effects of siltation indicated that silt can be a significant limiting factor to mussel distribution. Transplant studies showed that mussels transplanted into heavily silted areas exhibited poor survival over a one year period compared to mussels moved to unsilted habitats. Results indicate that siltation may interfere with reproductive activity. Laboratory experiments testing the effect of suspended silt on the uptake of C-14 tagged algae by freshwater mussels showed that suspended silt can interfere with feeding. Food uptake was reduced to approximately 50% (of control) at silt levels of 211 to 820 mg/l, and to 80% at silt levels over 1000 mg/l. It was concluded that the limiting mechanism is one of dilution of food rather than direct interference with filtration or respiration.
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    Ecology of algal mats and their role in the formation of stromatolites in Antarctic dry valley lakes
    Wharton, Robert A. (Virginia Polytechnic Institute and State University, 1982)
    Algal mats comprised primarily of Phormidium frigidum Fritsch, Lyngbya martensiana Menegh., and several species of pennate diatoms are found in the below-ice benthic regions of Lakes Bonney, Chad, Hoare, Fryxell, and Vanda, southern Victoria Land, Antarctica. Mats are also found in the littoral moats and ice-covers of several lakes, and in cryoconite holes on Canada Glacier. Variations in temperature, light, oxygen, salinity, and nutrient levels between lakes and different habitats in the same lake result in differences in species composition, morphology, biomass, and photosynthetic pigment content of the mats. Algal mats are trapping and binding sediment, and precipitating minerals, particularly calcite. Mats are removing organic and inorganic matter from the arheic lakes via transfer through the icecovers or by incorporation into the sediments. Some of the algal mats are laminated, organosedimentary structures and can be considered stromatolitic. Depending upon ambient and subsequent environmental conditions non-columnar, columnar, and pinnacle-shaped stromatolites are forming, some of which are partially lithified. If environmental variables (i.e. low light intensity, lack of burrowers or browsers, and relative lack of turbulence) associated with these stromatolites do not vary significantly, it is probable that they may result in a lacustrine carbonate sedimentary deposit.
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    Effect of a heavy metal on ecto- and vesicular-arbuscular mycorrhizal fungi: the physiology, ultrastructure, and ecology of copper stress and tolerance
    Gruhn, Christine Mae (Virginia Polytechnic Institute and State University, 1989)
    This work consists of an introduction, six chapters dealing with various aspects of the response of mycorrhizal fungi to copper, and a brief conclusion. The first chapter examines the enzyme tyrosinase in several ectomycorrhizal fungi and shows that its activity is altered in these fungi in response to copper. Polyamines are also examined in this chapter, and it is shown that their levels are altered in some ectomycorrhizal fungi due to copper stress but not in others. The second chapter uses transmission electron microscopy to demonstrate that copper is bound to the hyphae of ectomycorrhizal fungi grown on solid media, but the location of the binding varies between fungal species. In vitro copper tolerances of a number of ectomycorrhizal species are compared in this chapter and differences in tolerance are evident between species and between different isolates of the same species. In the third chapter, four ectomycorrhizal fungi and one nonmycorrhizal fungus are evaluated for their ability to improve the growth of Japanese Red Pine under conditions of copper stress. Improvement of pine seedling growth is not correlated with in vitro copper tolerance of the fungus, but is related to the degree of compatibility between host and fungus. Despite differences in in vitro tolerance between three isolates of the same species, there are no differences in the effect of the isolates on the tree host under conditions of copper stress. Ectomycorrhizal fungi were also inoculated in pairs on pine seedlings and the competitive abilities of the fungi are compared under stressed and nonstressed conditions. The fourth chapter discusses the results of inoculation of pine with a nonhost fungus which stimulates dichotomous branching of the root system. The compound responsible for the branching is demonstrated to be indole-3-acetic acid (IAA), a plant growth hormone. The final two chapters deal with endomycorrhizal fungi. In the first of the two, inoculation of onion with an endomycorrhizal fungus demonstrates that the fungus probably plays no direct role in the response of the plant to heavy metals, based on biomass production, nutrient uptake, and photosynthetic rate. The last chapter demonstrates that the vascular plants found on abandoned mines in Virginia and North Carolina are well colonized by endomycorrhizal fungi; thus, an absence of these fungi is not a reason for the limited natural recolonization of the mine spoils.
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    Effects of copper on benthic communities in artificial microcosms
    Comeaux, Jay Louis (Virginia Tech, 1996-04-05)
    Due to perceived shortcomings in some aspects of hazard assessment for chemicals administered to aquatic systems, experiments were conducted to determine the effects of copper on various ecological parameters in artificial streams and microcosms. Effects investigated were colonization and growth of periphyton communities in artificial streams, community composition and nutritional content of periphyton in these streams, leaf conditioning and nutritional content in laboratory microcosms, and nutritional suitability of these leaves to a shredding macroinvertebrate. Main effects observed in periphyton growth experiments were significant reduction in substrate colonization due to copper treatment, which led to significantly lower standing biomass in treated streams. Observed growth rates were generally similar between control streams and copper treated streams. Light treatments did not affect periphyton responses to copper. Community composition of the periphyton was affected by 2.5 μg/L copper. Periphyton phosphorus and nitrogen contents were not affected by copper treatment. Conditioning rate of leaves was significantly decreased by 50 μg/L copper treatments in some cases. Leaf phosphate and nitrogen contents were not significantly affected by copper treatment. Significant differences in nutritional suitability of copper-treated leaves to a shredding macroinvertebrate were not detected. These experiments suggest that aquatic primary producers are more sensitive to copper than heterotrophs. Additionally, adverse effects on periphyton were observed at concentrations well below measures of chronic toxicity to organisms dependent on periphyton as a trophic resource and the chronic criteria for copper. As such, greater emphasis should be placed on the sensitivities of periphyton communities in future copper criteria determination.
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    Environment risk assessment for toxic chemicals and genetically-engineered microorganisms: a microcosm approach
    Scanferlato, Vjera Sostarec (Virginia Tech, 1990)
    Microcosms were used in this research to assess the environmental risk associated with two types of stressors: genetically-engineered microorganisms (GEMs) and toxic chemicals. Approaches used to evaluate the potential environmental impact of these two stressors are fundamentally different, and arise mainly from the fact that the GEMs are living and capable of replication. Risk assessment for genetically-engineered Erwinia carotovora strain L-864 included investigations of its persistence and effect on structure and function of aquatic microcosms. Densities of genetically-engineered and wild type E. carotovora declined at the same rate in water or in sediment, falling in 32 days below the level of detection by viable counts. Selective media, antibiotic resistance, and most probable number analysis were used to enumerate genetically-engineered E. carotovora in environmental samples. This technique was able to detect as few as 1 to 10 target cells/10 g soil. In thermally-perturbed aquatic microcosms, genetically-engineered E. carotovora persisted significantly longer than in unperturbed microcosms, suggesting the vulnerability of stressed ecosystems to colonization by GEMs. Competition study showed that the genetically-engineered E. carotovora did not displace the wild type strain. Effects of genetically-engineered and wild type strain on indigenous bacteria belonging to specific functional groups important in nutrient cycling were similar: inoculation of either strain caused a temporary increase in densities of total and proteolytic bacteria, while it did not affect amylolytic and pectolytic bacteria. Treatment with engineered bacteria did not change biomass values of the receiving community, but caused a transitory increase in its metabolic activity. The inability of genetically-engineered E. carotovora to persist, displace resident species, and affect metabolic activity of a community indicates a low risk of adverse ecological effects in aquatic systems. Microcosms were also used to assess environmental risk for toxic chemicals. A study was conducted to assess the fate of sediment-associated copper and to investigate its effects on the structure and function of the aquatic community. Most of the added copper was bound to sediment particles. In microcosms containing 100 µg Cu/kg sediment, chlorophyll a content and respiration significantly decreased compared to the control. Addition of 1000 µg Cu/kg sediment caused a decrease in production, respiration, respiration/biomass ratio, ATP, and chlorophyll a. The last study compared responses of Simocephalus exspinosus (Daphniidae) to copper during a single-species test to responses of S. exspinosus populations in a microcosm test. Responses of S. exspinosus were similar in both test systems: there was an increased production of young at 30-46 µg Cu/l, while the organisms did not survive exposure to concentrations > 100 µg Cu/l. In these studies, microcosms showed a potential to predict fate and effects of chemical and biological contaminants released into the biosphere.
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    Environmental risk assessment of a genetically-engineered microorganism, Erwinia carotovora
    Orvos, David R. (Virginia Polytechnic Institute and State University, 1989)
    Environmental use of genetically-engineered microorganisms (GEMs) has raised concerns over potential ecological impact. Development of microcosm systems useful in preliminary testing for risk assessment will provide useful information for predicting potential structural, functional, and genetic effects of GEM release. This study was executed to develop techniques that may be useful in risk assessment and microbial ecology, to ascertain which parameters are useful in determining risk and to predict risk from releasing an engineered strain of Erwinia carotovora. A terrestrial microcosm system for use in GEM risk assessment studies was developed for use in assessing alterations of microbial structure and function that may be caused by introducing the engineered strain of E. carotovora. This strain is being developed for use as a biological control agent for plant soft rot. Parameters that were monitored included survival and intraspecific competition of E. carotovora, structural effects upon both total bacterial populations and numbers of selected bacterial genera, effects upon activities of dehydrogenase and alkaline phosphatase, effects upon soil nutrients, and potential for gene transfer into or out of the engineered strain. No significant difference was found in survival of the engineered strain as compared to its wildtype parent. Both strains survived for over two months in microcosms. The effects of both strains upon populations of total bacteria and selected bacterial genera were determined; while some effects upon community structure were observed, they were not significant. The engineered strain was not found to be a superior competitor compared to its parent; three different doses of engineered and wildtype strains were used. ln addition, neither strain affected activities of dehydrogenase or alkaline phosphatase in soil. Likewise, no effects were observed upon the nutrients monitored. However, transfer of the kanamycin resistance gene that had been inserted into the engineered E. carotovora strain may have occurred. Five species of indigenous bacteria displayed kanamycin resistance 15 days after being exposed to the engineered Erwinia. DNA from these strains was isolated, purified, and hybridization experiments executed to determine if any homology existed between these DNAs and the kanamycin resistance gene that had been inserted into E. carotovora. Using biotin-Iabeled probes and Iow-stringency washing conditions, homology was observed. However, before gene transfer can be proven, additional studies, including amplification and sequencing, may be required. Although a simple microcosm design was employed, it yielded sufficient information to conclude that release of the engineered Erwinia carotovora will not affect any of the microbial measures of integrity that were studied in a manner different from that of the wildtype. Effects upon plant material and other higher taxa will be the focus of future studies.
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    The evolution and ecological genetics of pupal color dimorphism in swallowtail butterflies (Lepidoptera: Papilioninae)
    Hazel, Wade Nelson (Virginia Tech, 1980-06-05)
    Data bearing on the evolution, environmental control and genetic basis of pupal color dimorphism was presented or discussed for six species of swallowtail betterflies. Papilla glauces and P. cresphontes produce only brown pupae while P. polyxenes, P. troilus, Battus philenor and Eurytides marcellus produce both green and brown pupae. Natural pupation sites of the species were located and results were generally consistent with the hypothesis of Sheppard (1958) which relates the evolution of the environmentally-cued dimorphism to environmental variation. The relative importance of texture, color and photo-period as environmental cues controlling the expression of pupal color was investigated and the results were discussed in relation to differences in the pupation sites of the species. The genetic basis of pupal color was investigated in E. marcellus by selecting for an increase in the tendency of larvae to produce green or brown pupae. The results were found to be consistent with the genetic basis of the trait as proposed by Hazel (1977). It was concluded that the primary factor responsible for the evolution of the dimorphism and the environmental cues which control its expression is nature of the pupation sites that a species utilizes.
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    Experiment as rhetoric in the cold fusion controversy
    Curfs, Garrit Thomas (Virginia Tech, 1990-04-05)
    An examination of the role of experiment in the cold fusion controversy is offered. It is argued that experimental results served as rhetorical tools in the service of actors in the controversy. Discourse analysis informed by actor network theory is employed to analyze the verbal and textual discourse of scientists involved in the construction of experimentally-based scientific knowledge. The practices actors employed to structure their discourse for rhetorical effectiveness are investigated. I conclude that if experiments are to retain their traditional role as arbiters of knowledge claims, the unit of analysis pertaining to "experiment" must be broadened to include not only experimental practices within the laboratory, but also the multitude of practices scientists perform outside the laboratory walls in order to increase the likelihood that their knowledge claims will be adopted by their disciplinary matrix.
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    Genetic analysis and phenotypic characterization of Lon mutants of Escherichia coli K-12
    Torres-Cabassa, Angel S. (Virginia Polytechnic Institute and State University, 1982)
    A systematic study of a collection of Lon⁻ mutants has been made in order to determine whether their pleiotropic phenotype is due to mutations affecting one or more genes. A fine structure map of the lon locus was constructed by Pl mediated generalized transduction. The lon⁻ mutations were found to map in two "clusters" within the region. Phenotypic characterization of a set of isogenic Lon⁻ strains derived from these experiments indicated that all Lon-associated phenotypes (e.g. sensitivity to UV irradiation, decreased ability to inherit plasmid and prophage, abnormal polypeptide degradation and regulation of capsular polysaccharide biosynthesis) are differentially expressed in Lon⁻ strains. A direct correlation exists between the intracistronic ordering of the lon⁻ alleles and the degree of expression the Lon⁻ phenotypes in each strain. All isogenic Lon⁻ strains exhibit conditional lethality upon a nutritional shift-up. However, some filamenting Lon⁻ mutants are not able to overcome this defect when exposed to growth conditions known to promote cell division in Lon⁻ strains. Evidence was obtained that suggest a role for nucleotide pools in the control of cell division and capsular polysaccharide production. Reversion studies indicated that all lon⁻ mutations studied are point mutations. The failure to generate deletions of the lon region in χ573, an F' strain carrying the lac to minE region on the plasmid, and the inability to cure F' strains carrying a lon⁻ mutation on the plasmid suggest that the lon gene product may be indispensable for the cell's survival. From transductional crosses, two intermediate phenotypic classes: UV-resistant, mucoid (UVRMuc), (Class A) and UV-sensitive, nonmucoid (UVSRou) (Class B), were obtained that did not segregate colonies of the opposite morphology. Genetic analysis of these strains by back-transduction into a proC⁻ lon⁺ background, indicated that complete genetic separation of all Lon-associated phenotypes tested was not achieved, although differences in the expression of some of these persisted. Data obtained from complementation analysis ruled out the presence of two genes at the lon locus. The patterns of complementation observed were compatible with the existence of one lon gene, having at least two distinct domains, and whose product is a multifunctional polypeptide.
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    The genetic basis of pupal color dimorphism in Papilio polyxenes and its maintenance by natural selection
    Hazel, Wade Nelson (Virginia Tech, 1976-06-05)
    A survey of the genetic variation in the ability to produce brown pupae was conducted using 23 broods reared from wild caught females. In addition a selection experiment was designed to investigate the genetic basis of the dimorphism. It was concluded that the genetic basis of the dimorphism is a threshold trait with quantitative genetic variation underlying the two phenotypes of green and brown pupal color. It was further concluded that the dimorphism is maintained in nature by weak stabilizing selection, thus explaining the occurrence of mismatches in pupal and background color.
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    Grass-counters, stock-feeders, and the dual orientation of applied science: the history of range science, 1895-1960
    Heyboer, Maarten (Virginia Tech, 1992-04-05)
    According to the predominant image, applied science is a linear, sequential process, the application of science. First scientists or applied scientists develop knowledge that satisfies the epistemic criteria of science, and applied scientists then find ways to use this certified knowledge to solve society's problems. There is, therefore, a sharp distinction between epistemic or scientific criteria and social criteria. The historical development of the applied ecological discipline called range science or range management demonstrates instead that applied science is a simultaneous process. Range science developed at a time when America increasingly looked to science to solve social, political, and economic problems in the hope that science's ability to predict could provide the basis for organization and rational management. The institutionalization of range science industrialized ranching. Ranchers appealed to a variety of traditional American values in response to this industrialization, but in the new context surrounding ranching those values had become illegitimate. From the outset, range science acquired a dual orientation toward both the epistemic criteria of science and the social criteria of society. That dual orientation introduced a tension into range science because it was not obvious how range scientists should satisfy both sets of criteria simultaneously. Researchers in different institutional contexts developed distinct resolutions to that tension. The most significant difference between the institutions were their political objectives and a difference in the power relations between range researchers and their audiences. Those institutional contexts defined the social criteria and provided the background to judge the acceptability of particular resolutions of the tension, in the process providing the motivation and justification for range science. Nevertheless, range science was not just politics by another means because range scientists also satisfied the epistemic criteria of science. The distinction between epistemic and social criteria therefore did not exist in the historical development of range science because range scientists simultaneously satisfied the epistemic criteria of science and the social criteria that flowed from different political objectives and different power relations between researchers and ranchers.
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    Human chromosomes: structure, abnormalities and birth defects
    Goradia, Ranjan Y. (Virginia Tech, 1977-08-05)
    The research presented in this dissertation consists of four papers that revolve around the structure of human chromosomes and their relationship to birth defects. A new technique is described to produce spiralization of human metaphase chromosomes. The important feature is heat followed by trypsin treatment. By varying conditions, it is possible to produce bands, spirals and intermediate states. An investigation of human metaphase chromosomes reveals identical lateral bands in sister chromatids when stained with Quinacrine mustard or Giemsa-trypsin. A hybrid of these two methods produces banding patterns which are different in sister chromatids yet may be repeated in homologous chromatids. A case study is presented in which a 3l-year old white female with a history of ovarian dysfunction and infertility delivered a male infant with trisomy 13. Her cultured leucocytes were mosaic for trisomy X. The natures of trisomy X and trisomy 13 are discussed with particular emphasis on the genetic transmission. In another case study of a family, it is found that some individuals who completely lack dermal ridges are mosaic for an extra X chromosome with deletions in both arms. A mechanism is proposed to account for the extra chromosome.
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    The identification of behavioral objectives for a human anatomy and physiology course supportive to the associate degree nursing programs in Virginia community colleges
    Eanes, Dolores Dove (Virginia Tech, 1978-07-15)
    The purpose of this study was to determine appropriate content objectives for a human anatomy and physiology course for associate degree nursing students. To accomplish the purpose,of the study, it was necessary to achieve the following goals: 1. Starting with an initial set of objectives for a course in human-anatomy and physiology for associate degree nursing students, obtain the opinions of three groups of nurse educators in regard to the importance value of each objective. 2. Rank order the objectives according to mean value of importance, based on the ratings given by each group of nurse educators. 3. Determine the extent of agreement of ranking across the three groups of nurse educators. 4. Use the mean ratings of the objectives produced by the three groups of nurse educators to make recommendations concerning the selection of objectives for a course in human anatomy and physiology for associate degree nursing students.
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    Industrial drug development: application of the theoretical framework of Abernathy, Clark, and Kantrow (1983) in an analysis of factors which determine productivity
    Griffiths, Robert Ian (Virginia Tech, 1988-05-31)
    This study identifies and analyzes factors which determine productivity in the drug industry. It shares a general concern about recent decline in industrial productivity in the United States with Abernathy, Clark, and Kantrow (1983), who developed a theoretical framework for analyzing the causes of lackluster industrial performance. According to Abernathy, et al. (1983), performance is determined by government fiscal and monetary policy, production capability, socioeconomic environment,(of which regulation is a subset), and corporate management. This study finds that the theoretical framework of Abernathy et al (1983) can be used as a context for analyzing productivity in the drug industry. In a recent case of drug development, socioeconomic and managerial problems caused costly delays in development, hampering the company's capacity to be productive. The study also finds that the strategy for industrial revitalization developed by Abernathy et al. (1983) is applicable to the drug industry. Specifically, corporate management must integrate the development activities of innovation, production, finance, and marketing more efficiently. More efficient integration will help management to consider the impact of one activity on the others, and to identify deficiencies which can delay development. This will help management cut development time and increase profits, which will help revitalize the drug industry.