Recent calls for reform in teacher education have included improving the clinical experience of preservice teachers (Boyer, 1983; The Holmes Group, 1986). Research on student teaching indicates that the role of the cooperating teacher is of critical importance to the clinical experience (Tabachnick, 1980; Haberaan, 1978). Problems exist, however, in communication gaps between higher education and the public schools (O'Shea, 1984); in the selection of cooperating teachers (Griffin, 1981); and in their preparation for assisting novices in the development of knowledge about teaching and learning (Griffin, 1983; Kleinsasser, 1988). Early clinical supervision models (Cogan, 1973); Goldhammer, 1969) have been presented through top-down approaches. Literature on teachers as a cultural group (Lortie, 1975) provides some insight into why such approaches have not been successful and why cooperating teachers have not come to see themselves as teacher educators. / Ed. D.

Thin-walled beam structures are adopted as structural members in various fields of modem technology including aeronautical/aerospacial, naval, mechanical and civil ones. With the advent of advanced composite material systems, there is a vital need to reformulate the classical theory of thin-walled beams in a wider framework. This dissertation is intended to incorporate several essential effects which have a considerable importance for the rational design of composite thin-walled beam structures. These effects are the transverse shear deformation, the warping constraint, the secondary warping as well as the hygrothennal and the dynamic ones. The field equations of laminated composite thin-walled beams of either open or closed single and multicell cross-sections are derived through the application of Hamilton's variational principle. The Laplace Transform technique is used to obtain exact solutions. In this dissertation, the aero elastic divergence instability of aircraft wings modelled as thin-walled beams as well as the eigenfrequency problem of cantilevered composite thin-walled beams of closed cross-section are considered in the framework of a reformed theory incorporating non-classical effects. The numerical results reveal the great role played by non-classical effects as well as by the tailoring technique applied to the problems studied in this dissertation. / Ph. D.

The object of this research was the development of on-line methods for the determination of the degree of substitution of cellulose esters. The focus of the effort was on the application of a Fourier transform infrared spectrometer (FT-IR) as an in-line detector for quantitative gel permeation chromatography (GPC). GPC/FT-IR has been used in the analysis of polymeric materials in the past, but not for quantifying the substituent content of cellulosics. This work has identified the infrared asymmetric nitrate absorptions of cellulose nitrates observed in THF and acetonitrile solutions. Independent absorptions for the primary nitrate at C₆ and secondary nitrate at C₃ were observed at 1651 cm⁻¹ and 1639 cm⁻¹ respectively. In addition, a third absorption at 1667 cm⁻¹ was observed to be dependent upon the degree of nitration of the cellulose nitrate. This absorption was found to be due to steric hindrance between secondary nitrate groups on the C₂ and C₃ sites. The infrared absorptions of cellulose acetate butyrates in THF, acetonitrile, and methylene chloride were also characterized. Separate absorptions for the acetyl and butyryl C-O-C asymmetric stretch were observed at 1235 cm⁻¹ and 1176 cm⁻¹ respectively. In acetonitrile and methylene chloride the carbonyl asymmetric stretching mode frequency observed at ≈1753 cm⁻¹ was found to be dependent upon the extent of acetyl substitution. This work developed a method for the quantitative determination of the degree of nitration of cellulose nitrates as a function of the polymer molecular weight using the asymmetric nitrate stretch. Methods for the determination of the acetyl and butyryl substitution of cellulose acetate butyrates were developed as well. Examples of each method applied to real world samples were carried out. / Ph. D.

Five studies were conducted to elucidate a possible mode of action of dietary organic acids in weanling pigs (n=536). The effect of feeding 1.5% fumaric or citric acid on growth performance, intestinal digesta pH, chloride ion concentration (Cl-), VFA profile and microflora populations was studied. In study 1, feeding citric acid improved ADG and feed conversion (F:G), whereas fumaric acid only numerically improved ADG and F:G. No significant dietary effect on intestinal pH, Cl- or VFA profile was observed. In study 2, feeding organic acids with and without a microbial supplement (Lactobacillus acidophilus) resulted in no interactive effects, but fumaric acid and the microbial supplement each improved ADG and F:G. In study 3, pigs fed organic acids were killed at -2, 0, 3, 7, 14 and 21 d postweaning. Organic acids had no significant effect on intestinal pH, Cl-, VFA profile or microflora populations. Postweaning age affected intestinal digesta measurements in these ways: pH decreased; VFA concentrations increased; lactobacillus decreased to d 3 postweaning; E. coli increased to d 7 postweaning; and clostridia decreased to d 21 postweaning. In study 4, pigs were fed organic acids and orally challenged with 10¹⁰ enterotoxigenic E. coli (0157:K88) (ETEC) at d 3, 7 and 14 postweaning. Organic acids had no measurable effect on intestinal pH, Cl- or VFA profile. ETEC challenge increased jejunum lactic acid concentration, lower colon VFA concentration and severity of scouring. Postweaning age affected these intestinal digesta measurements: cecum pH decreased; jejunum Cl- increased; jejunum lactobacillus count decreased; lower colon lactobacillus count increased; and E. coli count decreased in all intestinal sections. In study 5, pigs were fed organic acids and challenge with ETEC on d 3 postweaning. Organic acids had no significant effect on severity of scouring or protection against reduced growth performance from the ETEC challenge. The ETEC challenge resulted in an increased severity of scouring and a reduction in ADG of 20% and F:G of 19%. In summary, feeding organic acids generally improved weanling pig growth performance and had little effect on intestinal digesta measurements. Postweaning age did have an effect on intestinal digesta measurements. The primary mechanism of action of dietary organic acids does not seem to be the lowering of intestinal pH or modifications to the intestinal microflora, but may act as an additional energy source. / Ph. D.

During the 1984-85 school year, a metropolitan school system investigated the research on effective schools to determine which program, once put into place, would serve the system in the remediation of low academic achievement. The program chosen for implementation was the Teacher Expectations and Student Achievement (TESA) Program. This study examined the relationships between the frequency of use of TESA-prescribed behaviors in the classroom and (a) time lapse since TESA training, (b) who taught the TESA classes, (c) training type, (d) training quality, and (e) principal support. A teacher survey was developed to collect data on the five predictor variables. One hundred percent of the teachers responded. The TESA observation technique was employed to measure the criterion variable--the frequency of use of the TESA-prescribed behaviors in the classroom. Data were collected during the months of May and June in the 1988-89 school year. Correlations, t-tests, and stepwise regression analysis were employed to analyze the data. Who taught the TESA classes, time lapse since taking TESA training, and training type were found not to significantly predict the frequency of use of TESA behaviors in the classroom. However, statistically significant relationships were found between specific TESA behaviors and certain factors within the multi-item predictor variables of training quality and principal support. / Ed. D.

For one-dimensional uninmodal maps hλ(x) a binary tree which includes all the periodic windows in the chaotic regime is constructed. By associating each element in the tree with the superstable parameter value of the corresponding periodic interval we define a different unimodal map. After applying a certain renormalization procedure to this new unimodal map, we find the period doubling fixed point g(x) which depends on the details of the map hλ(x) and the scaling constant α. The thermodynamics and the scaling function of the resulting dynamical system are also discussed. In addition, the total measure of the periodic windows is calculated with results in basic agreement with those obtained previously by Farmer. Up to 13 levels of the tree have been included, and the convergence of the partial sums of the measure is shown explicitly. It is conjectured that the asymptotic behavior of the partial sum of the measure as the number of levels goes to 00 is universal for the class of maps that have the same order of maximum. A new scaling law has been observed, i.e., the product of the length of a periodic interval characterized by sequence Q and the scaling constant of Q is found to be approximately 1. We also study two three-dimensional volume-preserving quadratic maps. There is no period doubling bifurcation in either case. We have also developed an algorithm to construct the symbolic alphabet for some given superstable symbolic sequences for one-dimensional unimodal maps. Using this symbolic alphabet and the approach of cycle expansion the topological entropy can be easily computed. Furthermore, the scaling properties of the measure of constant topological entropy are studied. Our results support the conjectures that for the maps with the same order of maximum, the asymptotic behavior of the partial sum of the measure as the level of the binary goes to infinity is universal and the corresponding 'fatness' exponent is universal. Numerical computations and analysis are also carried out for the clipped Bernoulli shift. / Ph. D.

This dissertation presents a one-dimensional thermomechanical constitutive model for shape memory alloys based on basic concepts of thermodynamics and phase transformation kinetics. Compared with other developed constitutive relations, this thermomechanical constitutive relation not only reflects the physical essence of shape memory alloys, i.e., the martensitic phase transformation involved, but also provides an easy-to-use design tool for engineers. It can predict and describe the behavior of SMA quantitatively. A multi-dimensional constitutive relation for shape memory alloys is further developed based on the one-dimensional model. It can be used to study the mechanical behavior including shape memory effect of complex SMA structures that have never been analytically studied, and provide quantitative analysis for many diverse applications of shape memory alloys. A general design method for shape memory alloy actuators has also been developed based on the developed constitutive relation and transient thermal considerations. The design methodology provides a quantitative approach to determine the design parameters of shape memory alloy force actuators, including both bias spring SMA force actuators and differential SMA force actuators. / Ph. D.

Microwave spectroscopy was used to determine whether sulphonyl chloride isocyanate (SO₂CINCO) exists as a mixture of 71° and 110° isomers or as a single 94° isomer where the angle is the dihedral angle between the S-Cl bond and N = C bond, and whether the NCO group is linear or not. The microwave spectrum of SO₂CINCO was assigned for two isotopic species, SO₂³⁵CINCO and SO₂³⁷CINCO, by considering the Stark effect and the nuclear quadrupole splittings due to chlorine and nitrogen. Rotational constants and nuclear quadrupole coupling constants were determined from the assigned peaks. The bond angles and dihedral angles were derived from the six rotational constants of the two isotopes by imposing some constraints based on the electron diffraction study. The dihedral angle C = N-S-CI obtained in this study was 93.86 ± 0.04 ° and ∠NCO was 175.68 ± 0.02° . The results indicate that SO₂CINCO exists as the 94° form at the temperature (4° K) where the microwave spectrum was recorded and that the NCO group is not linear. / Ph. D.

The concept of subcortical dementia predicts higher rates of depressive symptomatology in dementia syndromes with predominant subcortical pathology. This hypothesis was evaluated by comparing the frequency and severity of depressive symptomatology in three diagnostic conditions: Alzheimer's disease (AD) (n=30) I subcortical vascular disease (SVD) (n=30), and Parkinson's disease (PD) (n=30). While AD and PD are prototypical exemplars of cortical and subcortical dementia syndromes respectively, SVD provides a test of the generality of the hypothesis as a subcortical neurodegenerative condition whose pathology is not confined to a single subcortical nucleus. A secondary aim of the study was to compare assessment methods for the ascertainment of depressive symptomatology. Assessment methods included the Hamilton Rating Scale for depression derived from interview with the patient's primary caregiver (HRSCG) and from interview with the patient (HRSEX), and the self-report Geriatric Depression Scale. The severity of current depressive symptomatology across the three neurodegenerative disorders followed a consistent pattern across each method of assessment. Specifically, scores on self-report (GDS) , examiner ratings (HRSEX), and caregiver ratings (HRSCG) of depression were most severe in patients with Parkinson's disease (PD), intermediate in subcortical vascular disease (SVD), and least severe in Alzheimer's the ascertainment of depressive symptomatology. Assessment methods included the Hamilton Rating Scale for depression derived from interview with the patient's primary caregiver (HRSCG) and from interview with the patient (HRSEX), and the self-report Geriatric Depression Scale. The severity of current depressive symptomatology across the three neurodegenerative disorders followed a consistent pattern across each method of assessment. Specifically, scores on self-report (GDS), examiner ratings (HRSEX), and caregiver ratings (HRSCG) of depression were most severe in patients with Parkinson's disease (PD) , intermediate in subcortical vascular disease (SVD), and least severe in Alzheimer's / Ph. D.

The biochemical pathway for the anaerobic degradation of gallate, pyrogallol and phloroglucinol by Eubacterium oxidoreducens was investigated. Phloroglucinol reductase was purified 90-fold, from the soluble fraction of cell extract, to electrophoretic homogeneity. The enzyme was an α₂ homodimer with a native M_r of 78,000, did not contain metals or cofactors and was specific for phloroglucinol and NADPH with a K_m of 800 μM and 6.7 μM respectively at pH 6.8. The Km for phloroglucinol decreased with increasing pH. The enzyme catalyzed reaction was reversible and the equilibrium constant was 9.6. Dihydroresorcinol was a competitive inhibitor of the reverse reaction (K_i = 756 μM). Dihydrophloroglucinol produced in cell extract with H₂ as the reductant was identical to the compound produced by sodium borohydride reduction of phloroglucinol as shown by ¹H NMR spectroscopy. The ¹³C NMR spectrum was consistent with the structural assignment of dihydrophloroglucinol. The mechanism of the proposed enzymatically catalyzed reaction is proposed to involve transfer of a hydride equivalent from NADPH to the carbonyl carbon of the phloroglucinol dianion. Mutant strains of E. oxidoreducens that showed no gallate decarboxylase or dihydrophloroglucinol hydrolase activity were isolated after mutagenesis with ethylmethane sulfonate and emichment with ampicillin. The decarboxylase deficient mutants were unable to grow on gallate while pyrogallol and phloroglucinol supported growth. The hydrolase deficient mutants were unable to grow on any aromatic substrates and converted gallate to pyrogallol and dihydrophloroglucinol. The conversion of gallate to non-aromatic intermediates by cell extract of the wild-type stain was dependent on the presence of 1,2,3,5-benzenetetrol for the conversion of pyrogallol to phloroglucinol and on formate for the reduction of phloroglucinol to dihydrophloroglucinol. Transhydroxylase activity involved in the conversion of pyrogallol to phloroglucinol was induced by growth on aromatic substrates. The formate dehydrogenase was located in the soluble fraction of cell extract, and activity was protected from oxygen inactivation by sodium azide. The Km for formate and NADP was 290 μM and 140 μM respectively at pH 7.5. The pH optimum for activity was 7.5 and maximum activity was observed at a temperature of 50°C. / Ph. D.