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This dissertation investigates the sluggish adjustment process of dividend payment in the stock market. First, I focus on the individual stocks. A casual investigation of observed dividends for individual stocks shows dividend adjustments are sluggish and discrete; this is not consistent with the Lintner??s stylized fact (1956) in which dividend adjustments are assumed to change continuously. Thus, I examine three possible explanations to account for dividend stickiness and discreteness: menu-costs (i.e. a constant adjustment cost), decision-making delays, and dividend adjustment asymmetry. I reject Dixit??s menu-cost model as an appropriate specification for the sluggish adjustment process of dividends. The empirical results imply that decisionmaking delays and dividend adjustment asymmetry might be possible explanations for sticky and discrete dividends on selected individual stocks. Second, I focus on the aggregate stock market. I use a quadratic adjustment cost model to examine whether adjustment costs can explain the slow adjustment of aggregate dividends. The empirical results suggest that adjustment costs might be a significant factor explaining the slow dividend adjustment for S&P 500. The value of relative weigh cost is related to the specification of target dividend. If target dividendsare related to earnings, then the empirical results suggest that the adjustment costs are about forty-fold more important than the deviation cost between the actual dividend and the target level in determining the dynamic dividend adjustment process. If target dividends are specified as proportion to the stock prices, the adjustment costs are about fourteen-fold more important than the deviation cost between actual dividend and target level when managers determine the dividends.

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Management of pest species is ordinarily required in the production of protected crops. Integrated pest management (IPM) is commonly used when controlling insects. The European Union Sustainable Use Directives states that "integrated pest management’ means careful consideration of all available plant protection methods and subsequent integration of appropriate measures that discourage the development of populations of harmful organisms and keep the use of plant protection products and other forms of intervention to levels that are economically and ecologically justified and reduce or minimise risks to human health and the environment. ‘Integrated pest management’ emphasises the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms.” Effectively monitoring pests is a key component of IPM, with decisions to use biological control agents (BCA) and insecticides often based on the presence of pests in traps. A commonly used monitoring tool is the sticky trap; these traps are coloured and rely primarily on their visual attractiveness to the pest. The capture efficiency of sticky traps can potentially be increased with the addition of light emitting diodes (LEDs). The objective of this project was to use LEDs to enhance the efficacy of yellow sticky traps for trapping a range of insect pests, to enable more effective timing of pest management by optimising pest monitoring. The addition of LEDs may also enable more effective mass trapping via yellow sticky traps, and minimize the trapping of beneficial insects. Comparisons between standard yellow sticky traps and those equipped with green (540 nm) or blue (480 nm) LEDs were carried out at four commercial growing facilities. Green (540 nm) LED equipped traps were compared with standard yellow traps in a mass release of the biological control agent Encarsia formosa Gahan (Hymenoptera: Aphelinidae), to determine if there are negative consequences to the addition of green (540 nm) LEDs when using this biological control agent. Relative spectral preferences of western flower thrips (Frankliniella occidentalis Pergande (Thysanoptera: Thripidea)) and Glasshouse whitefly (Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae)) were determined using a choice test comparing a range of wavelengths in 20 nm steps against a control wavelength. Green (540 nm), and blue (480 nm) LED equipped traps captured significantly more dark-winged fungus gnats (Bradysia difformis Frey (Sciaridae: Diptera)) and diamondback moths (Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae)) than those without. No significant differences were found between green (540 nm) LED equipped traps and those without for E. formosa, and a significant decrease in the capture of the shore fly parasitoid Kleidotoma psiloides Westwood (Hymenoptera: Figitidae) was observed. In behavioural experiments F. occidentalis showed a peak spectral preference at 360, 420, and 480 nm, and T. vaporariorum at 320, 340, and 380 nm. The addition of LEDs to yellow sticky traps enhanced their capture efficiency for some key pests in commercial protected crop growing environments, and has the potential to enable pest detection at an early stage, consequently optimising the timing of pest management options.

This thesis described the modification of glassy carbon (GC) electrodes with aminophenyl (AP) films via in situ reduction of aminobenzene diazonium ions. The characterisation of the AP modified GC was conducted electrochemically by oxidation of the AP functionalities in acidic aqueous conditions. Ferricyanide and ruthenium hexamine redox probes were also used to investigate the blocking properties of the AP films. Before electrochemical oxidation of the AP functionalities, AP films were shown to have a nett positive charge at pH 7. After electrochemical oxidation in protic conditions, the film was either neutral or negatively charged. The preparation of diazonium cation terminated surface, which is termed 'sticky surface', by reaction of the AP modified electrodes with NaNO₂ in acidic condition, was investigated and the sticky surface was electrochemically characterised. More than one species was formed in the reaction of the AP film with NaNO₂. The reactions of sticky surface with aniline, citrate- and thiol-capped gold nanoparticles (Au-nps) were also studied. Spontaneous reaction of sticky surface with thiol-capped Au-nps had been achieved, and suggested that the reaction leads to the formation of Au–C bonds, via the loss of nitrogen. However, for the reaction of the sticky surface with citrate-capped Au-nps, it was unclear whether covalent bonding had been achieved. The reason for this was due to the possibility of an electrostatic interaction between the negatively charged citrate-capped Au-nps and the positively charged sticky surface. The stability of the sticky surface in acidic aqueous conditions was studied electrochemically and by reaction with thiol-capped Au-nps. It was found that the diazonium cations on the sticky surface are not stable over one hour in aqueous acidic conditions, or even in low temperature. The electro-catalytic activity of the thiol-capped Au-nps attached to the GC electrode via sticky surface towards the oxidation of ascorbic acid was briefly examined, and the surface was found to catalyse the oxidation reaction.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 221-229).

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