Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1959. / Includes bibliographical references (leaf 291). / by DeWitt Ross Petterson. / Sc.D.

Wethers fitted with double re-entrant cannulae located in either the jejunal or ileal section of the small intestine were used to study the absorption characteristics of threonine, valine and methionine. Perfusions of the cannulated intestine were conducted 4 hr after feeding for a 1 hr period. Absorption of amino acids was measured as the total amount of amino acid removed from the perfusion solution during the 1 hr period. Concentrations of each amino acid ranged from 0.6 to 7.4 millimolar. The experiment design, a three dimensional central composite design, required only 15 different concentration combinations of the three amino acids used to determine their absorption characteristics. Removal of amino acid from the perfusion solution was constant over the 1 hr perfusion period, but absorption did vary with time after feeding at which the wethers were perfused. Four or 8 hr after feeding tended to have higher absorption rates than 2 or 6 hours. Absorption of each amino acid increased with each replication indicating that the cannulae remained healthy and functional. Wethers with cannulae located in the ileum absorbed more (P < .05) threonine, valine and methionine than those with jejunal cannulae. Equations were derived for each amino acid to predict the amount which would be absorbed when the initial concentrations of all three amino acids were known. Site of absorption and effluent volume were also part of the absorption prediction equations. Absorption of threonine and valine was affected by the quadratic component (P < .10) of their own concentrations. The linear and quadratic components of methionine concentration exerted a positive influence (P < .05) on methionine absorption. Site of absorption was not an important (P < .10) component of the prediction equation with the exception of methionine. Effluent volume was a significant (P < .01) component of all three absorption prediction equations. The amounts of each amino acid absorbed was dependent upon the initial concentration of that amino acid. As the initial concentration was increased, the amount absorbed increased, but no saturation points were noted. Absorption, as observed in this experiment, was subject to inhibition and stimulation by the other amino acids present in the perfusion solution. Valine was inhibitory of threonine absorption when present in low concentrations, but increasing the concentration of valine resulted in a stimulatory effect on threonine absorption. Methionine inhibited the absorption of threonine when valine was present at concentrations below 3 mM, but the stimulation of threonine absorption by high concentrations of valine was enough to override the inhibitory effects of methionine. The amount of valine absorbed was decreased by increasing the methionine concentration. Low concentrations of threonine decreased the amount of valine absorbed while high concentrations had a stimulatory effect at high concentrations of valine and low concentrations of methionine. Valine exerted inhibitory effects on methionine absorption when threonine was present in low concentrations and threonine was also inhibitory if valine was present at low concentrations. When the concentration of threonine was increased to 7.4 mM, each increase in valine concentration resulted.in more methionine being absorbed. / Ph. D.

Wethers fitted with double re-entrant cannulae located in either the jejunal or ileal section of the small intestine were used to study the absorption characteristics of threonine, valine and methionine. Perfusions of the cannulated intestine were conducted 4 hr after feeding for a 1 hr period. Absorption of amino acids was measured as the total amount of amino acid removed from the perfusion solution during the 1 hr period. Concentrations of each amino acid ranged from 0.6 to 7.4 millimolar. The experiment design, a three dimensional central composite design, required only 15 different concentration combinations of the three amino acids used to determine their absorption characteristics. Removal of amino acid from the perfusion solution was constant over the 1 hr perfusion period, but absorption did vary with time after feeding at which the wethers were perfused. Four or 8 hr after feeding tended to have higher absorption rates than 2 or 6 hours. Absorption of each amino acid increased with each replication indicating that the cannulae remained healthy and functional. Wethers with cannulae located in the ileum absorbed more (P < .05) threonine, valine and methionine than those with jejunal cannulae. Equations were derived for each amino acid to predict the amount which would be absorbed when the initial concentrations of all three amino acids were known. Site of absorption and effluent volume were also part of the absorption prediction equations, Absorption of threonine and valine was affected by the quadratic component (P < .10) of their own concentrations. The linear and quadratic components of methionine concentration exerted a positive influence (P < .05) on methionine absorption. Site of absorption was not an important (P < .10) component of the prediction equation with the exception of methionine. Effluent volume was a significant (P < .01) component of all three absorption prediction equations. The amounts of each amino acid absorbed was dependent upon the initial concentration of that amino acid. As the initial concentration was increased, the amount absorbed increased, but no saturation points were noted. Absorption, as observed in this experiment, was subject to inhibition and stimulation by the other amino acids present in the perfusion solution. Valine was inhibitory of threonine absorption when present in low concentrations, but increasing the concentration of valine resulted in a stimulatory effect on threonine absorption. Methionine inhibited the absorption of threonine when valine was present at concentrations below 3 mM, but the stimulation of threonine absorption by high concentrations of valine was enough to override the inhibitory effects of methionine. The amount of valine absorbed was decreased by increasing the methionine concentration. Low concentrations of threonine decreased the amount of valine absorbed while high concentrations had a stimulatory effect at high concentrations of valine and low concentrations of methionine. Valine exerted inhibitory effects on methionine absorption when threonine was present in low concentrations and threonine was also inhibitory if valine was present at low concentrations. When the concentration of threonine was increased to 7.4 mM, each increase in valine concentration resulted in more methionine being absorbed. / Ph. D.

The problem addressed in this study was: How do city council members serving cities in Virginia with populations of 50,000 or more perceive Virginia Cooperative Extension Service programs and clientele as they relate to urban concerns? The study determined (1) council members' perception of priorities that should be given to specific agency programs and clientele, (2) whether there was agreement between their perception of current agency priorities and what its priorities should be, (3) their perception of the agency's contribution and how it could be increased, and (4) the influence the variables of size of city and the agency's method of entry had on council members' perception. An ex post facto survey research design was utilized. The study population consisted of the total population of 78 council members serving the ten cities studied. Data were collected through individual structured interviews. The instrument solicited responses on Likert-type scales. One open-ended item solicited suggestions for increasing the agency's contribution. Primary analysis utilized descriptive statistics, Spearman rho rank order correlations, and chi-square tests of independence. Council members were highly unfamiliar with Virginia Cooperative Extension Service programs and clientele. They were most unfamiliar with Technical Resources and Community Resource Development programs. Council members felt the agency was placing proper rank order priority on program content areas and clientele, with the following exceptions: (1) lower priority should be placed on farmers as a client group and on the 4-H content area of providing educational resources for other city youth organizations and (2) higher priority should be placed on the 4-H content area of developing skills through real life experiences with projects in various areas. Members of council indicated that highest clientele priorities should be centered around youth, including problem youngsters, and other individual or social groups, including minorities, low income, homemakers, and senior citizens. High priority programs should center around conservation and concerns of families or family members. Relatively lower priority should be placed on business, industry, and government-related types of programs and clientele. The agency was perceived as making a contribution to urban citizens, but it was felt that the agency could increase its contribution by increasing publicity and public relations. Size of city and method of entry appeared to influence council members' perception of certain clientele and content areas. Size of city most often influenced perception of agricultural clientele and programs. Method of entry appeared to have particular influence on the perceived scope of the agency. Several conclusions were drawn that related to council members' perception of programs, clientele, and contribution. Council members have limited knowledge of the Virginia Cooperative Extension Service. However, they believe the agency and its programs are relevant to meeting the needs of urban residents. The agency seems to be closely identified with its initial method of entry into cities and that identity tends to persist. Council members believed that the agency's highest priorities should be given to assisting city residents with individual and social needs associated with urban living. / Ed. D.

The effect of a periodic source of a NO_x-SO₂ air pollution regime on the growth of forest trees was investigated. Radial increment growth studies were conducted to determine if correlations existed between emission levels of a source (predicted by production levels) and radial increment growth of forest trees. Three stands of loblolly pine, two of white pine, and one of sycamore proximal to the emission source were sampled by obtaining increment cores at d.b.h. (1.37 m from the base of the tree) from 50 trees in the dominant or codominant crown class of each stand. A multiple linear regression analysis utilizing annual radial increment growth as the dependent variable and the independent variables of annual production levels, total annual rainfall, annual seasonal rainfall, and age were used to evaluate all stands. An inverse relationship significant at the 0.001 level was demonstrated between growth and production levels in two loblolly pine stands and one white pine stand. The further analysis of these stands indicated respectively a 45%, 45%, and 10% theoretical reduction in diameter growth which was independent of symptom expression in white pine. Growth and production levels were not significantly correlated in the remaining loblolly pine stand and the sycamore stand; however, a positive relationship was exhibited in the second white pine stand. A field chamber study (utilizing charcoal filtered and nonfiltered air) with seedlings of red oak, sycamore, sweetgum, yellow poplar, white ash, green ash, and Virginia pine indicated significant inhibition of terminal elongation in Virginia pine and red oak in three locations surrounding the emission source. / Master of Science

Cambrian Shady Dolomite facies exposed northwest and southeast of Austinville, southwestern Virginia, apparently formed in a platform-to-basin setting. Northwest of Austinville, the Shady Dolomite (600 m thick) overlies the Lower Cambrian Erwin Formation and is overlain by the Middle Cambrian Rome Formation. Here the unit consists of ribbon-laminated carbonates (Patterson Member) overlain by massive dolomites and fenestral, cryptalgal carbonates (Austinville and Ivanhoe Members) which pass up into Rome Formation red mudcracked clastics and carbonates. Relict textures suggest that northwestern belts of the Shady Dolomite were deposited in an upward-shoaling sequence on the inner part of a carbonate platform. The Shady Dolomite thickens southeast of Austinville where exposed (400 m thick) upper Shady Dolomite beds (partly equivalent to Rome Formation) contain calcareous algal bioherms, limeclast grain-stone, monomictic and polymictic carbonate breccia and black laminated limestone and shale. Algal bioherms, limeclast grain-stones and carbonate breccias of southeastern belts suggest seaward, outer platform environments; black laminated limestone and shale units containing local algal bioherms and breccias may indicate local off-platform "deeper water" deposits. Slopes on the carbonate platform margin were probably low (few degrees) as indicated by interlayering of shallow and deeper water lithologies recording considerable migration of facies bands. This southeasternmost facies of the Shady Dolomite exposed in the Valley and Ridge may give important clues as to the lithologic character of equivalent units in the Virginia Piedmont. / Master of Science

Through treatment of selected interventions and artworks, the thesis investigates relationships between cybernetics, conceptions of intelligence and artistic practice. The works in question are primarily the artist's own, documented in the thesis and a separate portfolio. Specifically, intelligence's downside, the controversial notion of stupidity, has been reappropriated as a means of considering the way artists intervene and how art, as a system, functions. The term ‘artificial stupidity' was invented in reaction to a particular construal of what Artificial Intelligence (AI) meant. The notion has been employed since, and the thesis discusses interpretations and uses of it. One meaning relates to an ability to become, or make oneself, ‘stupid' in order to facilitate discovery. In the conclusions, the arguments are extended to ‘art as a social system' (Niklas Luhmann), suggesting that it survives and reproduces through a wily kind of pretend idiocy combined with occasional acts of generosity to other systems. The research methodology is threefold. Firstly, unapologetically playful approaches, characteristic of the artistic process, were utilised to generate ideas. Thus, art becomes primary research; an equivalent to experimentation. Secondly conventional secondary research; the study of texts; was conducted alongside artistic production. Thirdly the works themselves are treated as raw materials to be discussed and written about as a means of developing arguments. Work was selected on the basis of the weight it carries within the author's practice (in terms of time, effort and resources devoted) and because of its relevance to the thesis themes i.e. contemporary and post-conceptual art, the science of feedback loops and critiquing intelligence and AI. The second chapter divides interventions and outputs into three categories. Firstly, the short looping films termed ‘simupoems', which have been a consistent feature of the practice, are given attention. Then live art, in which a professional clown was often employed, is considered. Lastly a series of interactions with the everyday technological landscape is discussed. One implication, in mapping out this trajectory, is that the clown's skills have been appropriated. ‘Artificial stupidity' permits parking contravention images to be mistaken for art photography, for beauty to be found in courier company point-of-delivery signatures and for the use of supermarket self-checkout machines, but to buy nothing. The nature of the writing in chapter 2 and appendix A (which was a precursor for the approach) is discursive. Works are reviewed and speculations made about the relationship with key themes. The activities of artists like Glenn Lygon, Sophie Calle, Samuel Beckett are drawn upon as well as contemporary groupings Common Culture (David Campbell and Mark Durden) and Hunt and Darton (Jenny Hunt and Holly Darton). Chapter 3 includes a more structured breakdown and taxonomy of methods. Art theories of relevance including the ideas of Niklas Luhmann already mentioned, John Roberts, Avital Ronell, Mikhail Bakhtin, Andrew Pickering and Claire Bishop are called upon throughout the thesis. Interrogation of the work raises certain ethical or political questions. If there are good reasons for the unacceptability of ‘stupid' when applied to other human beings, might it be reasonable to be disparaging about the apparent intellectual capacities of technologies, processes and systems? The period of PhD research provided an opportunity for the relationship between the artist's activities and the techo-industrial landscape to be articulated. The body of work and thesis constitutes a contribution to knowledge on two key fronts. Firstly, the art works themselves, though precedents exist, are original and have been endorsed as such by a wider community. Secondly the link between systems and engineering concepts, and performance-oriented artistic practice is an unusual one, and, as a result, it has been possible to draw conclusions which are pertinent to technological spheres, computational capitalism and systems thinking, as well as art.

A new technique for conversion of carboxylic acids to carbinols under mild conditions has been developed. This technique requires first formation of enol esters by coupling N-ethyl-5-phenylisoxazolium3' -sulfonate with an appropriate carboxylic acid in acetonitrile, followed by reduction with a 10-fold molar excess of NaBH₄. In addition five carboxyl group "specific" reagents were surveyed for their ability to inactivate the sulfhydryl proteinase papain (EC 3.4.4.10). No inactivation of the enzyme was observed with three of the reagents, diazoacetamide, triethyloxonium tetrafluoroborate, and N-ethyl-5-phenylisoxazolium-3'-sulfonate. The remaining two reagents, N-ethoxycarbony1-2-ethoxy-1,2-dihydroquinoline and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide did indeed inactivate papain. Inactivation by N-ethoxycarbony1-2-ethoxy-1,2-dihydroquinoline appears to be the result of reaction of this reagent with the free thiol group of the enzyme. Treatment of papain with l-ethyl-J-(3-dimethylaminopropyl) carbodiimide resulted in modification of the free thiol group, in 6 to 10 of the nineteen tyrosyl groups, and in six of the fifteen free carboxyl groups. The free thiol group could be essentially completely protected from reaction by converting it to its mercuric derivative with HgCl₂, and the tyrosyl modification was shown to have no effect on enzymatic activity. Reaction of active or mercuripapain with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide in the presence of glycine ethyl ester resulted in incorporation of 6 ethyl glycinate residues per molecule of enzyme, with essentially complete inactivation. In the presence of benzamidoacetonitrile, a competitive inhibitor of papain, only four ethyl glycinate residues were incorporated into active papain with retention of ~80% of enzymatic activity, thus establishing that at least one and perhaps two of the six modified carboxyl groups were located in the active site of the enzyme. The identity of one of these carboxyl groups was postulated to be Asp-158, and thus some evidence was provided for the tentative assignment of a direct mechanistic role in catalysis for this amino acid residue. / Ph. D.

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

To what degree is it possible to score an artistic event for which the impetus is a social, rather than aesthetic, effect - and indeed, to what degree are these effects separable? How, in short, can the composer or artist create a blueprint for a relational practice that is fundamentally concerned more with actions within the community than it is with any outcomes or objects presented to the community? This thesis seeks to explore the role of the Other through the composition of a set of participatory scores for social activity. Devised from the perspective of a composer and sound-artist, this practice-led research investigates three strands of social engagement: collaboration, interpretation, and intervention. These strands each revolve around the problems inherent to performing and scoring socially-engaged, site-specific sound works, as well as the reality of their dissemination in the public domain. Each of the methods employed not only feeds back into the score-making process, but also serves to critique existing methods and hierarchies within artistic participation, ultimately arguing for an open-ended and non-linear relationship between the act of sensing, and the (community-influenced) construction of the sensible. Exploring post-structural, ethical, and ontological notions of what it means to share and construct community with Other, this research examines the role of art as a creative movement between self-constructs that are at once individual and indivisible from the community. This work argues that such creativity extends not only to the realisation of artworks, but across the whole gamut of activity within the social event. By undertaking practice-based research into the role of Other within the event of an artwork, this thesis interrogates the socio-political hierarchies inherent to both the specific art-event, and the pre-existing community in which such events unfold. As such, the art-event points not only to the specific creative act of its making, but equally the latent creativity within the community in which the art is disseminated. The spectator, no less than the artist, defines the terms of the community by which such acts are made available to perception as an ontological reading that is not only sensed, but sensible.