Cationic Cellulose Nanocrystals (CNCs) for Organic and Inorganic Colloids Flocculation

Cellulose nanocrystals were modified for use as novel flocculants by taking advantage of the extended cationic polymeric chains on CNCs. They were evaluated using both organic colloids and inorganic bentonite clay particles. For the flocculation of organic colloids, cellulose nanocrystals (CNCs) were grafted with N-N-(dimethylamino) ethyl methacrylate (DMAEMA), 4-vinylpyridine (4VP) and polyamine. The amine-g-CNCs displayed the best flocculation performance from the lowest optimal mixing ratio at pH=4 and wider flocculation window at pH=7. Bridging effect was more obvious for P4VP yielding relatively large flocs. The presence of carbonyl group of PDMA polymer chains promoted hydrogen bonding that contributed to aggregate latex particle in alkaline condition. For the inorganic clays, chitosan was utilized as natural polymer grafted onto CNCs. To enhance its water solubility, GTMAC were conjugated onto chitosan chains (G-chitosan) to produce the polymer flocculants. CNCs was firstly oxidized by sodium periodate to produce aldehyde groups, and G-Chitosan was grafted onto the aldehyde groups on CNCs to form novel polymer/nanoparticle, G-Chitosan/A-CNCs flocculants. For G-chitosan, the optimal dosages at pH 4 and 7 were 10 mg/L and 50 mg/L respectively. For the G-Chitosan/A-CNCs, the OD was 10 mg/L, 50 mg/L and 177 mg/L at pH 4, 7 and 10, respectively. The impact of the polymer was less significant when it was associated with CNCs particle. The role of CNCs in flocculants was related to its high aspect ratio and hydrophobic stiff backbone. Flocs parameters, such as size, shape and fractal dimension were further used to elucidate the significant of incorporating CNCs to the flocculants

Three Essays in Empirical Asset Pricing

This dissertation consists of three essays in empirical asset pricing concerning how investor attention and social interactions impact information diffusion in financial markets. In the first essay, I investigate how different investor attention facilitates information diffusion through the customer-supplier network. I find that retail attention improves information incorporation into asset prices and plays a stabilizing role in financial markets. In contrast, institutional attention exhibits a diminished role if I control for retail attention. In addition, I show that the attention of a potential group of informed retail investors, local retail investors, plays a price-stabilizing role beyond that of uninformed (non-local) retail investors. My results provide a refinement on the view of the role played by retail investors. While the literature argues that retail investors destabilize prices, my findings suggest that at least a group of informed retail investors can stabilize financial markets. In the second essay, I examine how social connectedness affects fund manager stock holdings during the COVID19 pandemic. I exploit the recent outbreak of COVID-19 as an exogenous shock to people's beliefs on the future economic condition to examine how fund managers from different regions make different decisions on stock holdings. By applying a unique dataset from Facebook that measures social interaction among different regions, I am able to identify managers from COVID-19 hotspot counties and those highly socially connected to the hotspot counties. I am also able to identify fund managers that are skilled using standard methodologies exploiting fund alpha and other performance metrics. The results show that managers located in or socially connected to hotspot counties sold more stock holdings during the outbreak of COVID-19 in the first quarter of 2020. However, such reductions appear panic-driven given subsequent behavior and outcomes and in particular given the contrasting behavior and outcomes for skilled versus unskilled fund managers. The evidence suggests that social interaction can intensify salience bias even for institutional investors if they are unskilled, but skilled managers appear relatively impervious to the deleterious effect of social networking. Finally, in the third essay, I explore the role of institutional and retail attention in the context of the media news releases and find nuanced evidence of the costs and benefits to market price adjustments flowing from investor attention to news. I show that retail attention does indeed destabilize financial markets by inducing price overreactions to positive news, but only if it is from uninformed retail investors. I find that when retail attention destabilizes the market, it is when retail investors appear to struggle digesting complex business information and then only if the news is of a positive sentiment; negative sentiment news and retail investor attention are not associated with market instability, possibly a result of the well-known reluctance of retail investors to short sell. I also find that institutional attention plays a stabilizing role in any context I explore, complex or simple news, positive or negative news sentiment, with or without retail investor attention

Management of Complicated Urinary Tract Infection

The management of complicated urinary tract infection (UTI) remains a challenge since the coexisted conditions may significantly decrease the successful rate of treatment. In this chapter, the specific conditions including indwelling catheter, urolithiasis, neurogenic bladder, vesicoureteral reflux and pregnancy are listed. In terms of each condition, the potential influence on UTI and management strategy is discussed. Not only is the current evidence reviewed but also we present our experience on management of complicated UTI

Macroeconomic News and Exchange Rates: Evidence of Unstable Effect

Although the link between macroeconomic news announcements and exchange rates is well documented in recent literature, this connection may be unstable. By using a broad set of macroeconomic news announcements and high frequency forex data for the Euro/Dollar, Pound/Dollar and Yen/Dollar from Nov 1, 2004 to Mar 31, 2014, we obtain two major findings with regards to this instability. First, many macroeconomic news announcements exhibit unstable effects with certain patterns in foreign exchange rates. These news effects may change in magnitude and even in their sign over time, over business cycles and crises within distinctive contexts. This finding is robust because the results are obtained by applying a Two-Regime Smooth Transition Regression Model, a Breakpoints Regression Model, and an Efficient Test of Parameter Instability which are all consistent with each other. Second, when we explore the source of this instability, we find that global risks and the reaction by central bank monetary policy to these risks to be possible factors causing this instability

Three Essays in Empirical Asset Pricing

This dissertation consists of three essays in empirical asset pricing concerning how investor attention and social interactions impact information diffusion in financial markets. In the first essay, I investigate how different investor attention facilitates information diffusion through the customer-supplier network. I find that retail attention improves information incorporation into asset prices and plays a stabilizing role in financial markets. In contrast, institutional attention exhibits a diminished role if I control for retail attention. In addition, I show that the attention of a potential group of informed retail investors, local retail investors, plays a price-stabilizing role beyond that of uninformed (non-local) retail investors. My results provide a refinement on the view of the role played by retail investors. While the literature argues that retail investors destabilize prices, my findings suggest that at least a group of informed retail investors can stabilize financial markets. In the second essay, I examine how social connectedness affects fund manager stock holdings during the COVID19 pandemic. I exploit the recent outbreak of COVID-19 as an exogenous shock to people's beliefs on the future economic condition to examine how fund managers from different regions make different decisions on stock holdings. By applying a unique dataset from Facebook that measures social interaction among different regions, I am able to identify managers from COVID-19 hotspot counties and those highly socially connected to the hotspot counties. I am also able to identify fund managers that are skilled using standard methodologies exploiting fund alpha and other performance metrics. The results show that managers located in or socially connected to hotspot counties sold more stock holdings during the outbreak of COVID-19 in the first quarter of 2020. However, such reductions appear panic-driven given subsequent behavior and outcomes and in particular given the contrasting behavior and outcomes for skilled versus unskilled fund managers. The evidence suggests that social interaction can intensify salience bias even for institutional investors if they are unskilled, but skilled managers appear relatively impervious to the deleterious effect of social networking. Finally, in the third essay, I explore the role of institutional and retail attention in the context of the media news releases and find nuanced evidence of the costs and benefits to market price adjustments flowing from investor attention to news. I show that retail attention does indeed destabilize financial markets by inducing price overreactions to positive news, but only if it is from uninformed retail investors. I find that when retail attention destabilizes the market, it is when retail investors appear to struggle digesting complex business information and then only if the news is of a positive sentiment; negative sentiment news and retail investor attention are not associated with market instability, possibly a result of the well-known reluctance of retail investors to short sell. I also find that institutional attention plays a stabilizing role in any context I explore, complex or simple news, positive or negative news sentiment, with or without retail investor attention