Call number: LD2668 .T4 1966 R923 / Master of Science

Polyribosome aggregation state in growing tissues of barley and wheat leaf or stems of pea and squash was studied in relation to seedling growth and water status of the growing tissue in plants at various levels of osmotic stress. It was found to be highly correlated with water potential and osmotic potential of the growing tissue and with leaf or stem elongation rate. Stress rapidly reduced polyribosome content and water status in growing tissues of barley leaves; changes were slow and slight in the non-growing leaf blade. Membrane-bound and free polyribosomes were equally sensitive to stress-induced disaggregation. Incorporation of ³²PO₄³⁻ into ribosomal RNA was rapidly inhibited by stress, but stability of poly(A) ⁺RNA relative to ribosomal RNA was similar in stressed and unstressed tissues, with a half-life of about 12 hours. Stress also caused progressive loss of poly(A) ⁺RNA from these tissues. Quantitation of poly(A) and in vitro messenger template activity in polysome gradient fractions showed a shift of activity from the polysomal region to the region of 20-60 S in stressed plants. Messenger RNA in the 20-60 S region coded for the same peptides as mRNA found in the polysomal fraction. Nonpolysomal and polysome-derived messenger ribonucleoprotein complexes (mRNP) were isolated, and characteristic proteins were found associated with either fraction. Polysomal mRNP from stressed or unstressed plants were translated with similar efficiency in a wheat germ cell-free system; activity of nonpolysomal mRNP was variable, but usually less than that of polysomal mRNP. Deproteinization of mRNP failed to improve its activity. No inhibition of translation of poly(A) ⁺RNA by nonpolysomal mRNP was observed in mixing experiments with the wheat germ cell-free system. It was concluded that no translational inhibitory activity was associated with nonpolysomal mRNP from barley prepared as described.

Master of Science / Department of Journalism and Mass Communications / Hyunseung Jin / With regards to the third-person effect, the purpose of this paper is to answer the fundamental question ‘who are others?’ when assessing the perceived effects of anti-tobacco advertising and cigarette advertising. The particular interest in this study is investigation of the underlying mechanism of the third-person effect between non-smokers and smokers by applying the social comparison theory to the third-person effect. Findings indicate that, in terms of overall third-person effect judgments, people are inclined to consider as others those persons sharing similar demographic characteristics including gender, race, and age. However, in terms of smoking status, people have a tendency to contrast themselves with other smokers rather than non-smokers, regardless of whether or not they themselves smoke. Moreover, the first-person effect toward an anti-tobacco advertisement was found amongst non-smokers, but it was not found amongst smokers. The magnitude of the third-person toward a cigarette-advertisement effect was greater among non-smokers than it was among smokers.

The purpose of this research was to determine the effects of retinoic acid on bovine papillomavirus (BPV) transformed cells. Since BPV transformed cells are able to form colonies in agar and their untransformed counterparts are not, of particular interest was the effect of retinoic acid on this marker. Retinoic acid inhibited the growth of colony forming cells, but the extent of inhibition varied among several cloned cell lines. Retinoic acid inhibited the proliferation of BPV transformed cells and the extent of this inhibition also varied. The copy number of the virus was determined for each of three cell lines by liquid reassociation experiments. The copy number did not change when the cells were treated with RA for a prolonged period of time. Gel electrophoresis and Southern blotting of extrachromosomal DNA from the cell lines revealed the presence of unit length BPV DNA in all three transformed cell lines. The amount of BPV DNA per cell was decreased when the cells were treated with 10⁻⁵ M RA for three days.

Haloxyfop-methyl 2-[4-[ [3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoate, fluazifop-butyl (±)-2-[4-[ [5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoate, and sethoxydim 2- [1-(ethoxyimino)butyl]-5- [2-(ethylthio)propyl] -3-hydroxy-2-cyclohexen-1-one modified chloroplast pigment, growth, anatomy, and ultrastructure of pre- and postemergent-treated wheat (Triticum aestivum 'Pavon 76') seedlings. Seedlings were grown under 16 h photoperiod (105 μE/M²/S) at 32/24 C day/night temperature. Pigment, growth and anatomical studies were made on pre- and postemergent-treated seedlings. Postemergent treatments were applied to 6-day-old seedlings. Carotenoid levels were reduced by 90 to 94% in preemergent-treated seedlings at 5 x 10⁻⁵ M for each herbicide. Postemergent application of 10⁻³ M haloxyfop-methyl and sethoxydim caused a reduction of 11 and 15% in carotenoid concentration than the control, respectively. Also, they produced a significant reduction in chlorophyll a and total chlorophyll concentration. Preemergent treatment with 5 x 10⁻⁶ M of each herbicide caused a reduction of 78 to 91% in leaf fresh weight and 72 to 84% reduction in root dry weight as compared to the control. Height of the seedlings was reduced by 79 to 86% of the control. Postemergent treatments with 10⁻³ M of each herbicide reduced the length of the second leaf by 98%, whereas length of the first leaf was reduced by 36% following haloxyfop-methyl treatment and 45% following fluazifop-butyl or sethoxydim treatments. Fresh weight of leaf tissue treated with 10⁻³ M of each herbicide was reduced by 40%. Preemergent treatment of the seedlings with 3 x 10⁻⁶ and 5 x 10⁻⁶ M haloxyfop-methyl or with 5 x 10⁻⁶ M fluazifop-butyl or sethoxydim caused 35 to 50% enlargement of mesophyll cells as compared to the control. These cells appeared to contain less cytoplasm. Post- emergent application of 10⁻³ M of each herbicide caused swelling of mesophyll cells. Ultrastructural studies showed that plastids of seedlings germinated in 5 x 10⁻⁶ M of each herbicide were disrupted, swollen, and lacked internal thylakoids but contained masses of plastoglobuli. The chloroplasts of postemergent-treated seedlings had fewer granal and intergranal thylakoids, but the injury to plastids was less severe than in preemergent treatments.

Bilinguals have repeatedly shown to have better results than monolinguals in non-verbal cognitive tasks that require inhibition of distracting stimuli. Evidence suggests that this enhanced performance is due to training effects of non domain specific executive functions, and that this gain in cognitive performance can contribute to a cognitive reserve in old age. One of the most frequently used methods when studying the relationship between second language proficiency and cognitive abilities is the Simon task in the visual sensory modality. The present study aimed to determine if the advantage found in the visual Simon task also could apply to a tactile Simon task. The sample consisted of 40 individuals aged 43 to 64 with different levels in their second language. An operational span test (OSPAN) was used to control for working memory capacity. No significant correlation was found between bilingualism and the Simon effect in either modality. Since the study has low statistical power and a small range in second language proficiency, it was concluded that further research investigating whether the bilingual advantage found in the visual Simon task can be found across modalities is necessary before any conclusions regarding a relationship between bilingualism and cognitive control can be made.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

The well-known field of engineering psychology, also known as human factors engineering, utilizes psychologists to solve Engineering's problems that concern the behavior of humans in their operation and control of engineering systems such as military aircraft. To limit psychology's relation to engineering this way is, however, counterproductive. Psychology requires a broader conceptualization of engineering psychology, a subfield of psychology, within which the psychologist's major concern is with the behavior of psychoengineering systems that affect the reliability, validity and safety of psychological research and practice. In contrast with human-factor systems, the psychoengineering systems include healthy and unhealthy, human and animal subjects. The affiliated problems are not those of the engineering industry. This study in engineering psychology concerned the safety of two electrical stimulation systems that are used on animals, chiefly dogs, in punishment and escape/avoidance conditioning procedures of psychology. The study referenced two safety questions. First, is the electricity, when applied externally to the ventral neck of the animal, capable of stimulating carotide sinus and vagus nerves to the point of dangerously disrupting systemic blood pressure and sinus rhythm? Second, is the electricity capable of damaging the epidermis when it is applied repeatedly to the same two points of contact? Of forty-two anesthetized dogs, half were tested with a punishment system; the remainder were tested with an escape/avoidance system. Each was stimulated for five seconds, five times, at each of five intensities. Inter-stimulus interval was about thirty seconds. Systemic blood pressures and electrocardiograms (ECG) were recorded. Control and experimental biopsies were taken for histological examinations of electrified and unelectrified specimens. Each animal's neck was examined grossly each day for ten days following the stimulation runs. None of the gross examination reports was positive. An exact binomial test supported the hypothesis that tissue samples from control and experimental biopsies did not differ histologically. Repeated measure ANOVAs were used to detect significant differences in systolic pressures, diastolic pressures, and R to R intervals of the ECG throughout stimulation runs. While there were some statistically significant results, there was no clinical significance, especially with regard to safety hazards.

The number of studies estimating neighbourhood effects has increased rapidly during the last two decades. Although results from these studies vary, a majority find at least small effects. But to what extent can we trust these estimates? Neighbourhood effect studies face many serious methodological challenges, of which some are related to the fact that people move. The mobility of individuals may cause neighbourhoods to change over time, result in exposure times that are too short and seriously bias estimates. These methodological problems have not been given enough attention in the neighbourhood effect literature: no study controls for them all, and implications of mobility are rarely included in theoretical discussions of neighbourhood effects. In a comprehensive summary and five different papers, I argue that the two scholarly fields of residential mobility and neighbourhood effect studies are intrinsically connected and that any arbitrary separation between the two is both conceptually problematic and risks leading to erroneous conclusions. Studies of neighbourhood effects must address the problems caused by mobility, before it can be convincingly argued that results actually show neighbourhood effects. To do this, longitudinal data are necessary. Furthermore, the connection between the two fields may also have implications for studies of residential mobility.

This thesis focuses on investigating the stability, dynamics and physical mechanisms of thermocapillary flows undergoing phase change by means of direct numerical simulations and experiments. The novelty of the general approach developed in this work lies in the fact that the problems under consideration are addressed with novel fully-coupled transient two-phase flow models in 3D. Traditional simplifications are avoided by accounting for deformable interfaces and by addressing advection-diffusion mechanisms not only in the liquid but also in the gas. This strategy enables a realistic investigation of the interface energy and mass transfer at a local scale for the first time. Thorough validations of the models against theory and experiments are presented. The thesis encompasses three situations in detail: liquid layers in saturated environments, liquid layers in unsaturated environments and evaporation of liquid droplets. Firstly, a model grounded in the volume-of-fluid method is developed to study the stability of laterally-heated liquid layers under saturated environments. In this configuration, the planar layer is naturally vulnerable to the formation of an oscillatory regime characterized by a myriad of thermal wave-like patterns propagating along the gas-liquid interface, i.e. hydrothermal waves. The nonlinear growth of the instabilities is discussed extensively along with the final bulk flow for both the liquid and gas phases. Previously unknown interface deformations, i.e. physical waves, induced by, and enslaved to, the hydrothermal waves are reported. The mechanism of heat transfer across the interface is found to contradict previous single-phase studies since the travelling nature of the hydrothermal waves leads to maximum heat fluxes not at the points of extreme temperatures but somewhere in between. The model for saturated environments is extended in a second stage to assess the effect of phase change in the hydrothermal waves for the first time. New numerical results reveal that evaporation affects the thermocapillary instabilities in two ways: the latent energy required during the process tends to inhibit the hydrothermal waves while the accompanying level reduction enhances the physical waves by minimizing the role of gravity. Interestingly, the hydrothermal-wave-induced convective patterns in the gas decouple the interface vapour concentration with that in the bulk of the gas leading to the formation of high (low) concentrations of vapour at a certain distance above interface cold (hot) spots. At the interface the behavior is the opposite. The phase-change mechanism for stable layers is also discussed. The Marangoni effect plays a major role in the vapour distribution and local evaporation flux and can lead to the inversion of phase-change process, i.e. the thermocapillary flow can result into local condensation in an otherwise evaporating liquid layer. The third problem discussed in this thesis concerns with the analysis of evaporating sessile droplets by means of both experiments and 3D numerical modeling. An experimental apparatus is designed to study the evaporation process of water droplets on superheated substrates in controlled nitrogen environments. The droplets are simultaneously recorded with a CCD camera from the side and with an infrared camera from top. It is found that the contact line initially remains pinned for at least 70% of the time, period after which its behaviour changes to that of the stick-slip mode and the drop dries undergoing contact line jumps. For lower temperatures an intermediate stage has been observed wherein the drop evaporates according to a combined mode. The experimental work is complemented with numerical simulations. A new model implementing the diffuse-interface method has been developed to solve the more complex problems of this configuration, especially those associated with the intricate contact-line dynamics. Further insights into the two-phase flow dynamics have been provided as well as into the initial transient stage, in which the Marangoni effect has been found to play a major role in the droplet heating. For the first time, a fully-coupled two-phase direct numerical simulations of sessile drops with a moving contact line has been performed. The last part of this work has been devoted to the investigation of three-dimensional phenomena on drops with irregular contact area. Non-sphericity leads to complex three-dimensional drop shapes with intricate contract angle distributions along the triple line. The evaporation rate is found to be affected by 3D features as well as the bulk flow, which become completely non-axisymmetric. To the best of our knowledge, this work is the first time that three-dimensional two-phase direct numerical simulations of evaporating sessile drops have been undertaken.