A Study of Stock Market Fluctuations and their Relations to Business Conditions

Most research on stock prices is based on the present value model or the more general consumption-based model. When applied to real economic data, both of them are found unable to account for both the stock price level and its volatility. Three essays here attempt to both build a more realistic model, and to check whether there is still room for bubbles in explaining fluctuations in stock prices. In the second chapter, several innovations are simultaneously incorporated into the traditional present value model in order to produce more accurate model-based fundamental prices. These innovations comprise replacing with broad dividends the more narrow traditional dividends that are more commonly used, a nonlinear artificial neural network (ANN) forecasting procedure for these broad dividends instead of the more common linear forecasting models for narrow traditional dividends, and a stochastic discount rate in place of the constant discount rate. Empirical results show that the model described above predicts fundamental prices better, compared with alternative models using linear forecasting process, narrow dividends, or a constant discount factor. Nonetheless, actual prices are still largely detached from fundamental prices. The bubble-like deviations are found to coincide with business cycles. The third chapter examines possible cointegration of stock prices with fundamentals and non-fundamentals. The output gap is introduced to form the non-fundamental part of stock prices. I use a trivariate Vector Autoregression (TVAR) model and a single equation model to run cointegration tests between these three variables. Neither of the cointegration tests shows strong evidence of explosive behavior in the DJIA and S&P 500 data. Then, I applied a sup augmented Dickey-Fuller test to check for the existence of periodically collapsing bubbles in stock prices. Such bubbles are found in S&P data during the late 1990s. Employing econometric tests from the third chapter, I continue in the fourth chapter to examine whether bubbles exist in stock prices of conventional economic sectors on the New York Stock Exchange. The ‘old economy’ as a whole is not found to have bubbles. But, periodically collapsing bubbles are found in Material and Telecommunication Services sectors, and the Real Estate industry group.

Global factors affecting women's participation in leadership

This dissertation is a multi-level, cross-cultural study of women in leadership conducted with both macro-society data and individual-level data aggregated to the country level. The research questions are, “What macro and micro forces are hindering or advancing women into business or political leadership?” “How do these forces impact the level of women's involvement in business and political leadership in a particular country?” Data was collected from 10 secondary sources, available for 213 countries, and includes about 300 variables for business leadership (N=115) and political leadership (N=181). To date, most women in leadership research has been Western- or US-based, and little rigorous empirical, multi-level research has been done across countries. The importance of cross-cultural studies on women in leadership stems from the potential to better understand why some countries have more women in positions of both business and political leadership; and the factors that affect women's involvement in such positions in different countries. A “Levels of Women's Participation in Leadership” country model is tested using cluster and discriminant analyses. Results indicate that the factors that affect women?s participation in leadership in countries with fewer women leaders are different from the factors that affect women's participation in countries with high levels of participation. This dissertation proposes that initiatives to increase participation of women in leadership need to consider the relevant factors that significantly affect countries at certain Levels of Women's Participation in Leadership. ^

Characterization of the Anti-Quorum Sensing Activity Exhibited by Marine Macro algae of South Florida

Quorum sensing is a communication mechanism employed by many bacteria. The bacteria secrete signal molecules known as acyl homoseriene lactones (AHLs) that cue to population size/density. Bacteria can be alerted of this optimum population by the concentration of these signal molecules. When the concentration of AHLs exceed a threshold valve, they enter the bacterial cell and causes the transcription of genes encoding virulence factors necessary for their colonization and survival. The marine algae Delise a pulchra, found off the coast of Australia is thought to produce compounds that inhibit the activity of the AHLs. The algae employ these compounds, known as furanones, as an anti-fouling agent. We postulated that marine algae of South Florida might contain similar activity; we screened 30 different algal species and found 22 species had the activity. Algal extracts were made from Halimeda incrassata using hexane, chloroform, ethyl acetate and methanol as solvents. The extracts were assayed for anti-quorum sensing activity. The results showed many of the South Florida green algae to possess anti-quorum sensing activity, however extracts of H incrassata did not show quorum sensing inhibition.

Global Factors Affecting Women's Participation in Leadership

This dissertation is a multi-level, cross-cultural study of women in leadership conducted with both macro-society data and individual-level data aggregated to the country level. The research questions are, “What macro and micro forces are hindering or advancing women into business or political leadership?” “How do these forces impact the level of women’s involvement in business and political leadership in a particular country?” Data was collected from 10 secondary sources, available for 213 countries, and includes about 300 variables for business leadership (N=115) and political leadership (N=181). To date, most women in leadership research has been Western- or US- based, and little rigorous empirical, multi-level research has been done across countries. The importance of cross-cultural studies on women in leadership stems from the potential to better understand why some countries have more women in positions of both business and political leadership; and the factors that affect women’s involvement in such positions in different countries. A “Levels of Women’s Participation in Leadership” country model is tested using cluster and discriminant analyses. Results indicate that the factors that affect women’s participation in leadership in countries with fewer women leaders are different from the factors that affect women’s participation in countries with high levels of participation. This dissertation proposes that initiatives to increase participation of women in leadership need to consider the relevant factors that significantly affect countries at certain Levels of Women’s Participation in Leadership.