Thesis (M.Sc)--University of Limpopo, 2010. / Black tea (Camellia sinensis) and black tea combined with bush tea (Athrixia phylicoides) were analyzed for their polyphenol content, antioxidant activity and tannin content. Solvent extraction methods were used for extracting polyphenols, antioxidant activity and tannin content. Total phenols were determined using the Folin-Ciocalteu method, antioxidant activity using Trolox Equivalent Antioxidant Capacity (TEAC) assay and tannin content using vanillin-HCl method. Polyphenol content, antioxidant activity and tannin content were calculated using regression equation Y=MX+C, where C=intercept, Y= Absorbance of the sample and M= Gradient. Results of black tea in this study showed that total polyphenols, antioxidant activity and tannin content decreased with decrease in temperature and time and this was attributed to the release of polysaccharides at 90°C. At 90°C for 3 minutes 7.68mg/100g of total polyphenol, 3.85μmol/g of antioxidants and 2.81mg/100g of tannin were obtained and this amount decreased to 5.50mg/100mg for total polyphenols, 1.31μmol/g for antioxidant activity and 0.72mg/100mg for tannin content at 30°C for 10 minutes. Combining the two tea types (50:50) resulted in a significant (p<0.005) decrease in total polyphenols, antioxidant and tannin content. Results of this study showed that at high temperature of 90°C for 3 minutes 2.64mg/100g for total polyphenol, 2.48μmol/g for antioxidants and 1.8mg/100g for tannin were obtained and these amounts decreased to 1.39mg/100mg for total polyphenols, 0.35μmol/g for antioxidant activity and 0.64mg/100mg for tannin content at 30°C for 10 minutes. Thus high brewing temperature causes increase in total polyphenols, antioxidant activity and tannin content of the combined teas. This study showed that black tea and combined black tea and bush tea solutions had large TEAC radical scavenging activity which can be related to total polyphenols and catechins. The antioxidant activity of the tea solution increased with increase in extraction temperature and duration of soaking. It is recommended that 3-min soaking temperature of 90 °C of black tea and combined bush tea and black tea can be used due to the highest total polyphenols and antioxidant activity obtained.

Globally, changes in plant community structure have occurred in ecosystems where humans have altered natural disturbance regimes. Many plants have adaptive life histories and morphological traits that have coevolved with fire and herbivory, which allows them to thrive despite repeated tissue losses. Therefore, altering the type, frequency, or severity of disturbance affects individual plant growth and competition among species. When these changes benefit or disadvantage different plant functional groups (i.e., grasses, shrubs, trees) it alters ecosystem structure and function. Understanding and predicting these vegetation changes, is critical for conservation and management of biodiversity, wildlife habitat, livestock forage, and water. Savannas are characterized by the codominance of grasses and trees, but the proportion of tree cover responds dynamically to changes in precipitation, fire, and herbivory. These factors often cause a ‘demographic bottleneck,’ which delays transitions from sapling size (1 m). In this dissertation, I investigated several fire × herbivory interactions to gain a mechanistic understanding of sapling recruitment processes that ultimately affect savanna structure. I made use of a long-term experiment that used semi-permeable fencing to manipulate presence and absence of different types of herbivores, to explore how fire and different combinations of domestic cattle, meso-wildlife, and megaherbivores (elephant and giraffe) affect sapling recruitment. First, I found clear evidence that a wide range of tree height classes resprout after being top-killed by fire, but they were all subsequently kept short by meso-wildlife browsing. Elephants played a key role in suppressing the largest resprouts after fire possibly because fire had reduced the presence of ant mutualists that defend the trees. Second, I found that in the absence of fire, cattle and wildlife indirectly affected saplings by altering competition with neighboring vegetation. Saplings competed with grass and trees during above-average rainfall years. Bare ground—a condition often caused by overgrazing—was positively associated with sapling growth. The highest sapling growth, however, occurred where large neighbor trees were absent, a condition maintained primarily by elephants browsing and damaging large neighbor trees. Finally, I found that saplings conditioned by pre-fire wildlife “browsing legacies” had high tolerance to combined fire and wildlife browsing. These results help explain how saplings tolerate repeated tissue loss to disturbance. Understanding how interactions between fire and herbivory affect sapling recruitment will help managers effectively use natural disturbance processes to manage savanna structure and function.

No description available.

Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2008.

No description available.

This thesis examines the extent to which sugar bush management in Eastern Ontario might contribute to biodiversity maintenance and conservation and therefore be promoted as a form of rural sustainable development. Ontario government policy seeks to actively promote actions that strengthen the province’s rural communities and protect biodiversity. Therefore sustainable development is an important concept to encourage in rural areas. The production of maple syrup on sugar bushes has already been demonstrated to be economically, socially, and in some aspects ecologically sustainable. This study seeks to determine how the operation of sugar bushes might also contribute to ecological sustainability through the maintenance and conservation of forest biodiversity. I identified three documents published by the Eastern Ontario Model Forest (EOMF): a set of management principles for conserving biodiversity on private woodlots, a list of biodiversity indicators, and a manual for monitoring them. I monitored three of the biodiversity indicators (spring ephemerals, birds, and frogs) on three of the larger sugar bushes in the Eastern Ontario and established that the EOMF biodiversity monitoring practices and guidelines were suitable for working sugar bushes. Using the management principles for biodiversity conservation developed by the EOMF, I interviewed 22 sugar bush operators in Eastern Ontario. With these interviews I addressed two objectives: 1. To generate empirical information regarding the management practices of maple sugar bush operators in Eastern Ontario and to compare these with established management principles for forest biodiversity conservation in the region 2. To generate suggestions for woodlot operators and government policymakers alike about future opportunities for research and management decision-making. The results of the study show that although most operators do not have a formal management plan for their sugar bush, many of their management practices are consistent with prescribed biodiversity conservation principles. Sugar bush operators are receptive to conserving biodiversity on their properties. The findings suggest that through sound management and planning, small-scale commercial sugar bush operations generally can be made environmentally sustainable, and become important components in broader rural development strategies. This study provides new insights into how small-scale sugar bush management, when practiced well, is consistent with conservation principles and with sustainable development principles more generally. It shows how sugar bush operators in Eastern Ontario can help the province reach its goals of biodiversity conservation and rural development set out in Ontario’s Biodiversity Strategy (2005) and Ontario’s Rural Plan (2004).

This is a rhetorical study of President George W. Bush’s use of the - ideographic dialectic in his appeals for support for war in Afghanistan and Iraq, as well as reelection in 2004. I argue that President Bush’s use of the - dialectic in each case provided him with specific rhetorical resources that enhanced his ability to seek support from the four discourse communities that constitute the foreign policy public: unilateralists, multilateralists, regionalists and coalition builders. The terministic flexibility of the ideographic dialectic worked well enough to encourage meanings in each foreign policy discourse community that were consonant with that group’s worldview. This allowed Bush to appeal to the disparate groups and appear as though he advocated their desired policies, when in fact, he did not promote any specific policy. This project contributes to the theoretical understanding of the ideograph by complicating the concept of the public. Further, it adds credence to claims that the War on Terror is a never-ending war.

The efficacy of the 2001 and 2003 Bush tax cuts was a major topic of discussion in the 2010 midterm elections. I investigate the effect of the possible expiration and eventual extension of the dividend tax cut on US stock market performance in 2010 based on the methodology used by Amronin, Harrison and Sharpe (2008). I compare aggregate performance of US common stocks relative to foreign stocks using equity indices, and examine cross-sectional performance amongst US stocks by creating different stock portfolios based on their dividend yield. This comparison is done over two event windows, (1) 20-24 September 2010 and (2) 3-8 December 2010. Consistent with previous studies, I find that the US stock market did respond to negative and positive news on the extension of the Bush-era dividend tax cuts, with stock prices falling and rising, respectively. My findings also suggest that this aggregate effect was probably muted by the redistribution of funds by investors from lower-yield to higher-yield stocks. Unlike in 2003, however, in the post-financial crisis context of 2010, the redistribution seemed to particularly favor stocks with medium-dividend yield, rather than smaller, higher-risk stocks with the highest dividend yield.

This thesis examines the extent to which sugar bush management in Eastern Ontario might contribute to biodiversity maintenance and conservation and therefore be promoted as a form of rural sustainable development. Ontario government policy seeks to actively promote actions that strengthen the province’s rural communities and protect biodiversity. Therefore sustainable development is an important concept to encourage in rural areas. The production of maple syrup on sugar bushes has already been demonstrated to be economically, socially, and in some aspects ecologically sustainable. This study seeks to determine how the operation of sugar bushes might also contribute to ecological sustainability through the maintenance and conservation of forest biodiversity. I identified three documents published by the Eastern Ontario Model Forest (EOMF): a set of management principles for conserving biodiversity on private woodlots, a list of biodiversity indicators, and a manual for monitoring them. I monitored three of the biodiversity indicators (spring ephemerals, birds, and frogs) on three of the larger sugar bushes in the Eastern Ontario and established that the EOMF biodiversity monitoring practices and guidelines were suitable for working sugar bushes. Using the management principles for biodiversity conservation developed by the EOMF, I interviewed 22 sugar bush operators in Eastern Ontario. With these interviews I addressed two objectives: 1. To generate empirical information regarding the management practices of maple sugar bush operators in Eastern Ontario and to compare these with established management principles for forest biodiversity conservation in the region 2. To generate suggestions for woodlot operators and government policymakers alike about future opportunities for research and management decision-making. The results of the study show that although most operators do not have a formal management plan for their sugar bush, many of their management practices are consistent with prescribed biodiversity conservation principles. Sugar bush operators are receptive to conserving biodiversity on their properties. The findings suggest that through sound management and planning, small-scale commercial sugar bush operations generally can be made environmentally sustainable, and become important components in broader rural development strategies. This study provides new insights into how small-scale sugar bush management, when practiced well, is consistent with conservation principles and with sustainable development principles more generally. It shows how sugar bush operators in Eastern Ontario can help the province reach its goals of biodiversity conservation and rural development set out in Ontario’s Biodiversity Strategy (2005) and Ontario’s Rural Plan (2004).

This dissertation examined the presidential elections of 1992, 1996 and 2000 for the narrative tools used to persuade Latino voters. Using Walt Fisher's narrative theory, I evaluated the various parts of the American Dream myth, looking specifically at the characters and settings used in the candidate's narrative. Then, I evaluated the values in those narratives through the lens of the Plan of Delano, specifically looking for ways these candidates actually reinforced important Latino values. The new tellings of the American Dream myth valued specific characters- characters that had been blessed by the American Dream. Clinton's 1992 character had to work to gain success, but he was also blessed. George P. Bush (George W. Bush's nephew) was another character blessed by the American Dream. As a first-generation American, he represented the hope that brings many to America; the idea that their children could have opportunities the parents could not. The settings of the American Dream story were also important. These settings varied greatly-from the decrepit and desolate to the fanciful and idyllic-but they represented all the different places where the American Dream is possible. Hope, Arkansas is not a place where much hope seems to exist. But even a community as impoverished as Hope can be the birthplace of a President, because of the amazing ability of the Dream to permeate even the darkest corners of America. The barrios of the Southwest appear to be hopeless, but as Clinton's telling of the myth reminded Latinos, even people growing up in the barrios should have hope-because the American Dream can exist anywhere. These values, these characters, these settings have added to the rich rhetorical history of the American Dream myth. These presidential candidates expanded the places where that hope could reach, and the people who could be blessed by the Dream. All of this culminated in a story that Latinos could relate to, that they shared in and that rhetorically persuaded them to believe in these candidates.