Spruce wood meal (Picea pungens), sequentially solvent pre-extracted with water, ethyl ether, and ethanol were subjected to acidolytic delignification treatments of increasing severity, and the lignin sol fractions were analyzed with regard to chemical structure and molecular architecture. Treatments with 0.2 N HCL in 90% aqueous dioxane ranged between 12 hr. at room temperature and 8 hrs. at reflux. The analysis of the dissolved lignin (sol) fractions indicate significant changes in the chemical structures only with regard to aryl-alkyl ether and phenolic hydroxyl content, and with regard to molecular weights and molecular weight distributions. While alkyl-aryl ether content decreases rapidly with acidolysis treatment under reflex conditions, phenolic hydroxyl content increases conversely. Molecular weight increases as delignification procedes. As crosslink density is a function of alkyl-aryl ether content, these results suggest that the 6 7 crosslink density of the sol fraction decreases while molecular weight increases. This contradicts to the theoretical behavior for the degradation of an infinite network and suggests that lignin in wood exists as a gel (network polymer) of extremely low crosslink density or as an ungelled, branched polymer only. Delignification is therefore not controlled by degelation but rather by interaction with carbohydrates via covalent or hydrogen bonds and/or by physical entrapment in the cell wall matrix. This is in accord with earlier hypothesis on the controlling effects of pore structure by Goring et. al. and transient ether linkages by Glasser. / M.S.

A method for the preparation of polydimethylsiloxane-urea (A-B)n segmented or multiblock copolymers has been investigated. These copolymers were synthesized from 4,4¹-diphenylmethane diisocyanate (MDI) and a,ω-bis(aminopropyl)polydimethylsiloxane (PSX) of different molecular weights by solution polymerization. The conditions needed to synthesize well-defined and high molecular weight siloxane-urea copolymers in high yields were investigated. 2-ethoxyethyl ether (2-EEE) was a better reaction solvent than tetrahydrofuran (THF) because the polymerization kinetics appear to be faster and the molecular weights obtained were higher. The mechanism postulated was based on the fact that THF is a stronger base than 2-EEE and the former should complex, more tightly with the isocyanate groups present in the system, competing with the amine nucleophile and resulting in the decrease in the polymerization kinetics. Penetration studies as a function of temperature using TMA showed the copolymers were multiphase and retained their integrity up to 160-180°C, a temperature range at which softening and consequently thermoplastic flow was observed. Apparently, the urea hard segment domains act as physical or pseudo crosslinks in the rubbery phase and also clearly serve as reinforcing filler materials. Efforts to chain extend siloxane-urea copolymers with 1,6-diaminohexane (HMDA) using several different techniques in the presence of cosolvents such as DMAC or NMP, only resulted in low molecular weight products due to the premature precipitation of the polymer. A polyurethane prepolymer formation study done in either DMAC or o-butyrolactone (BLO) at about 105°C, showed BLO to be the better solvent. Side reactions involving isocyanate (-NCO) groups are less prevalent in BLO. ESCA was used to probe the surface chemical composition of polyether-urethane (Estane C-5), polydimethylsiloxane-urethane (PUS) copolymers and their blends. The topmost surface of the neat Estane is mostly covered with the polyether (PTMO) soft segments mixed with small amounts of the urethane hard segments. The surface of the neat polydimethylsiloxane-urethane (PUS) is almost an overlayer of the polydimethylsiloxane (PSX) segments. ESCA results strongly suggest the PSX layer to be at least 50Å thick. In the hlends studied, the trend towards having greater percentages of the silicon and hence siloxane on the surface starts dramatically at a level of around 1-2 wt. % of siloxane in the bulk. The location of such a transition in a particular blend system is important because it allows one to in a sense "tailor" the surface concentration of siloxane in these blends. / M.S.

The gymnastics manual for student-teachers has been prepared to give the student-teacher the opportunity to get acquainted with gymnastics skills, cognitive information, conditioning exercises, curriculum development, and audiovisual media, needed to teach gymnastics. Student-teachers' responsibilities and student-teachers' program are discussed. Information is also provided concerning basic material in the school curriculum to get started in the student-teaching experience. The gymnastics section presents detailed description of skills for female and male events, spotting techniques and common errors committed by beginners. Addresses of companies where audiovisual materials, gymnastics charts and safety information can be purchased, are provided. The Student-Teacher Gymnastics Manual is the beginning of a new wave of educational literature, seeking well prepared professionals in the school curriculum. / M.S.

Concentrations between 5000 and 15000 mg/liter undecanol applied as foliar sprays were effective in pinching most varieties of chrysanthemum tested. Cultivars varied in their response. Subapical phytotoxicity increased with increasing concentrations and was generally more variable among cultivars than was the pinch response. Concentrations effective in pinching without subapical phytotoxicity resulted in plants similar to manually pinched plants with respect to height and number of branches. Studies conducted in the growth chamber and greenhouse indicate environmental factors exert a major influence on plant response to undecanol. In general, conditions which favor more rapid drying tended to decrease the number of plants pinched and reduce the number of plants showing subapical phytotoxicity. Comparing air temperature, air flow, relative humidity, and light (PAR), temperature was the single most highly correlated environmental variable with both pinching and phytotoxicity in the greenhouse study. Many of these variables are, however, highly interrelated with one another so that a change in one results in a change in others. Prediction equations using concentration and environmental variables were developed for pinching and phytotoxicity. Undecanol foliar sprays of 7500 mg/liter were nearly 100% effective in pinching two cultivars with minimal phytotoxicity when applied 9 to 18 days after planting. Pinching was significantly reduced in plants treated prior to 9 or later than 18 days after planting. Manually pinched plants were generally taller than chemically pinched plants treated the same day. Chemically pinched plants generally produced more branches than manually pinched plants. Day of treatment did not affect flowering of chemically pinched plants; however, chemically pinched plants tended to flower slightly later than manually pinched plants. Finished plants pinched chemically were comparable to those produced by manual pinching. / Ph. D.

The role of gene flow in population differentiation was examined by electrophoretic analysis of populations of two species of goodeid fishes, Goodea atripinnis and Chapalichthys encaustus, from lakes and streams on the Mesa Central of Mexico. Microgeographic differentiation was observed among continuous stream populations of Goodea. Highly significant genic heterogeneity was exhibited among continuous lacustrine populations of both species. Levels of differentiation (based on a genetic distance coefficient) among populations of G. atripinnis in Lake Chapala were similar to levels among populations from a number of isolated drainages. These results suggested that population continuity and gene flow do not necessarily imply genetic continuity and allele frequency homogeneity. Neighborhood effects (population subdivisions due to behavioral constraints such as homing or low vagility) were proposed as contributing to reductions in gene flow among populations from lakes and streams, but at least in the case of Goodea were not of major importance. Data from Lake Chapala for both species lended support to intralacustrine or sympatric models of lacustrine species flock evolution. Population comparisons of Goodea from a number of drainage systems suggested that a simple time-since-divergence model was insufficient to explain the observed patterns of genetic variation. Local effects (drift, bottlenecks, selection) were proposed as important mediators of genetic variation and population differentiation. It is suggested that levels of gene flow much greater than the “one migrant” rule would still permit differentiation of populations in the absence of selection. / Ph. D.

To better understand the genetics of stalk quality in elite Corn Belt germplasm, combining ability estimates for stalk quality as measured by rind puncture were obtained for twelve inbred lines of maize representing elite Corn Belt germplasm. Secondly, an attempt was made to assess the practical utility of the rind penetrometer as a tool to measure stalk quality in an applied maize breeding program. The twelve inbred lines of maize were crossed in a diallel manner to produce the 66 F₁ single cross hybrids. Hybrids were hand planted in single-row plots with three replications at Holland, Virginia on 10 April and 15 and 16 April, 1981 and 1982, respectively. Plots were comprised of four split-plots corresponding to planting densities of 39,536, 49,420, 59,304 and 69,188 plants per hectare. Rind puncture data were collected from five competitive plants in each density for each hybrid at midsi lk and two to three weeks later. Data were also collected on percent erect plants, stalk pinch values, and grain yield. Analyses of variance were performed on the means for each hybrid-density combination for all traits. Model I, Method 4 of Griffing (1956) was followed to obtain estimates of GCA and SCA effects. Highly significant differences were detected among hybrids and densities for rind puncture and grain yield in both years. Significant differences were also detected among hybrids for percent erect plants and stalk pinch value, although no significant difference among densities was evident. No significant difference was detected between dates of measurement for rind puncture. nents were highly significant for all GCA and SCA compotraits. Hybrid by density interaction was significant for grain yield and percent erect plants but not for rind puncture or stalk pinch. Hybrid by date interaction for rind puncture was highly significant in 1982 only. Considerable additive genetic variation associated with GCA was detected for rind strength as measured by rind puncture in elite Corn Belt germplasm. The rind penetrometer appears to be a useful tool to aid the breeder in identifying genotypes with superior rind strength, which in turn is a component of total stalk strength. / Ph. D.

Age and reproductive data from 67 bobcat carcasses and lower jaws were collected during the 1979-80 and 1980-81 trapping seasons. Sex and age data on 41 additional bobcats taken in the 1977-78 and 1978-79 trapping seasons were provided by the Virginia Commission of Game and Inland Fisheries. The mean age from the 4-year pooled sample was 2.83 ± 0.24 (S.E.) years, with 25% juveniles, maximum age 12 years, and sex ratio approximately 1:1. Scent-station survey data did not parallel harvest records except in Region IV (Piedmont) where both were increasing. No correlation between bobcat pelt prices and harvest was established but bobcat harvest was correlated with prices of fox and raccoon pelts (r=0.87 and 0.81 respectively, p ≤ 0.10). License sales were not correlated with bobcat harvests. Bobcat harvests were inversely related to precipitation in 3 regions and to snow and sleet in another region. Mail survey responses indicated that most sportsmen (56%) believed bobcats to be increasing and 20% believed the population to be stable. The majority of Game Wardens (89.7%) reported that they thought the population to be stable or increasing. The survey indicated that 69.1% of the bobcats trapped are taken incidentally to trapping for other species. Taxidermists reported receiving 13-16% of the annual harvest. Survey responses from the Game Wardens and tag records indicated that bobcats occur almost statewide. Northampton Counties and may be increasing their range. Models based on population characteristics suggest that the population is at best stable and probably declining. / M.S.

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No description available.

Si on fait l'historique de la théorie du rêve à travers les penseurs et les diverses croyances et cultures, deux grands courants se dessinent et trouvent à s'exprimer parallèlement: la thèse empathique du rêve d'abord -thèse transcendantale, théories théologiques, théories télépathiques prémonitoires, etc...- et ensuite la thèse psycho-analytique. La th.se empathique altérologique, remontant à l'antiquité., est tombée en défaveur avec l'avènement des théories freudiennes. Elle connait, depuis, une éclipse qui perdure. La thèse psychanalytique, d'une façon générale, tente d'expliquer le rêve par l'examen des scénarios du rêve, en rapport avec l'état psycho-affectif du rêveur. Elle a des précurseurs rationalistes avec les interrogations d'Aristote, Quintus, Saint Albert; elle connaît un puissant développement avec Freud et Jung et les contemporains, en passant par Bergson et une foule d'autres penseurs importants dans le développement de la pensée. Ces deux thèses semblaient fondamentalement s'opposer. On les croyait irréconciliables. Toutefois, en appliquant les méthodes symbologiques d'investigation psycho-analytiques dans la thèse empathique, l'analyste se dote d'un atout précieux pour décrypter et interpréter le langage empathique du rêve. Fondues en une synthèse qui se veut modestement nouvelle et originale, les deux thèses deviennent L'hypothèse psycho-empathique où le message altérologique -venu d'un autre psychisme- est revu par un rêveur, transformé selon le mode onirique, sous un langage égologique propre au rêveur. Il doit être soumis à l'analyse si l'on veut en trouver la langue d'origine ou le sens.