Thesis (MSc (Viticulture and Oenology. Wine Biotechnology))--University of Stellenbosch, 2002. / Pathogen devastation of food products has been the topic of extensive research efforts worldwide. Fungal infections are foremost amongst these pests, contributing not only to losses in product yield, but also significantly affecting the quality thereof. It is not surprising then that producers of these foodstuffs and their derived products continually strive towards the highest possible product quality. Therefore, it remains imperative that satisfactory methods are implemented to control these fungal pathogens. The current strategies are all hampered by drawbacks, and severe crop losses are still experienced. New technologies are being explored; one such technology is the genetic transformation of plant species. This method has enabled scientists to introduce foreign genes, with known functions and predictable outcomes, into plants. Genes identified to be involved in disease resistance have become the focus of numerous research efforts concerned with the improvement of the plant's innate defence response. This study aimed to enhance disease resistance to fungal pathogens by means of the genetic transformation of two genes previously shown to be involved in disease resistance. These genes encode polygalacturonase-inhibiting proteins (PGIPs) from Phaseolus vulgaris and resveratrol synthase from Vitis vinifera. PGIPs specifically inhibit the action of fungal polygalacturonases (PGs), which are enzymes responsible for the hydrolytic breakdown of plant cell walls. These enzymes were also found to be the first enzymes that are secreted by fungal pathogens during infection of the host plant. Additionally, PGIP-PG interaction results in the existence of molecules involved in the activation of plant defence responses. Resveratrol, the product of resveratrol synthase, exerts its antifungal action by destruction of the microbial cellular membranes. These mentioned genes were transformed alone, and in combination, into Nicotiana tabacum and the resultant transgenic lines were evaluated for enhanced disease resistance and for possible synergistic effects between the transgenes. Several independent transgenic lines were regenerated with genes integrated into the tobacco genome. Almost all the plants harbouring only pgip or vst1 genes also expressed these genes at a high frequency. Some non-expressing lines were identified from the transgenic plants that had integrated both genes, but several lines were obtained expressing both transgenes. Good correlations were observed between transgene product activity and enhanced resistance to the fungus Botrytis cinerea in an antifungal in planta assay. Lines showing the highest PGIP activity and resveratrollevels were more resistant to the pathogen, leading to disease resistance of up to 80% seven days after inoculation in comparison to an untransformed control. These lines maintained their strong inhibition, even three weeks post-inoculation, showing a complete halt in disease development and fungal growth. These results provide good indications of the efficacy of these transgenes in the upregulation of plant defence. However, the study will have to be expanded to include even more transgenic lines to elucidate the possible synergistic effects of these genes. In an additional pilot study, genes encoding for precursors and for the formation of resveratrol were introduced into the yeast Saccharomyces cerevisiae. The resultant recombinant yeast strains were evaluated for their ability to produce the phenolic substance, resveratrol. This compound has been implicated in beneficial aspects relating to human health, including positive effects on atherosclerosis and platelet aggregation as a direct result of its antioxidant and anti-inflammatory activities. Recombinant yeast strains were constructed that expressed genes coding for coenzyme A ligase and resveratrol synthase. These strains were shown to be able to produce the phenolic compound resveratrol from the precursors present in the yeast as well as from the products introduced with the transformation. The resveratrol was complexed with an added glucose moiety. These results are extremely positive, considering the possibility of manipulating wine yeasts to produce resveratrol during the wine fermentation, thereby adding to the health aspects of both red and white wine. This is the first report of the production of this compound by the introduction of genes necessary for its biosynthesis in a foreign host. This study has confirmed the importance of PGIPs and resveratrol in the effort to enhance disease resistance in plants through genetic transformation technology. It has also shown that the health benefits of resveratrol could be exploited more optimally in the wine industry, by producing wine yeasts with the ability to synthesise this important antioxidant.

Approved for public release, distribution is unlimited / Many potential adversaries seek, or already have theater ballistic missiles capable of threatening targets of interest to the United States. The U.S. Missile Defense Agency and armed forces are developing and fielding missile interceptors carried by many different platforms, including ships, aircraft, and ground units. Given some exigent threat, the U.S. must decide where to position defensive platforms and how they should engage potential belligerent missile attacks. To plan such defenses, the Navy uses its Area Air Defense Commander (AADC) system afloat and ashore, the Air Force has its Theater Battle Management Core Systems (TBMCS) used in air operations centers, and the Missile Defense Agency uses the Commander's Analysis and Planning Simulation (CAPS). AADC uses a server farm to exhaustively enumerate potential enemy launch points, missiles, threatened targets, and interceptor platform positions. TBMCS automates a heuristic cookie-cutter overlay of potential launch fans by defensive interceptor envelopes. Given a complete missile attack plan and a responding defense, CAPS assesses the engagement geometry and resulting coverage against manually prepared attack scenarios and defense designs. We express the enemy courses of action as a mathematical optimization to maximize expected damage, and then show how to optimize our defensive interceptor pre-positioning to minimize the maximum achievable expected damage. We can evaluate exchanges where each of our defending platform locations and interceptor commitments are hidden from, or known in advance by the attacker. Using a laptop computer we can produce a provably optimal defensive plan in minutes. / Lieutenant, United States Navy

Approved for public release, distribution is unlimited / Disc carving is an essential element of computer forensic analysis. However the high cost of commercial solutions coupled with the lack of availability of open source tools to perform disc analysis has become a hindrance to those performing analysis on UNIX computers. In addition even expensive commercial products offer only a fairly limited ability to "carve" for various files. In this thesis, an open source tool known as Foremost is modified in such a way as to address the need for such a carving tool in a UNIX environment. An implementation of various heuristics for recognizing file formats will be demonstrated as well as the ability to provide some file system specific support. As a result of these implementations a revision of Foremost will be provided that will be made available as an open source tool to aid analysts in their forensic investigations. / Civilian, Federal Cyber Corps

This study investigates the effects of insider entrenchment on Chief Executive Officer (CEO) compensation in firms conducting an initial public offering (IPO). The sample comprises 220 US firms that went public between 1996 and 2002. Corporate governance choices regarding entrenchment are captured by six provisions in the corporate charter and bylaws, as well as five anti-takeover statutes, which may or may not be in effect in the state of incorporation. Firm-level items are supermajority requirements for charter amendments, bylaws amendments, and merger approvals, along with the presence or absence of a staggered board of directors, poison pills, and golden parachute agreements. The anti-takeover laws examined are Business Combination, Control Share Acquisition, Fair Price, Poison Pill Endorsement, and Constituencies Statutes. A factor analysis reveals three distinct components of entrenchment: firm- and state-level external entrenchment and firm-level internal entrenchment. External entrenchment is related to market control over management by means of corporate takeovers; internal entrenchment relates to shareholder control over management by means of their voting power. Evidence is found for a positive association between entrenchment at IPO and subsequent CEO cash and total compensation. These relationships are driven by firm-level external entrenchment. Firm-level external entrenchment is also significantly and positively associated with CEO stock-based compensation. The positive effects of entrenchment at IPO on CEO compensation appear not to be transitory and remain constant for at least five years post-IPO. Furthermore, entrenchment at IPO is shown to affect CEO pay-for-performance sensitivity. On balance, entrenchment reduces the sensitivity of CEO compensation to stock returns and returns on assets. The results of this study underscore the crucial importance of insiders' governance decisions made at the time of the IPO. Little support is found for a re-balancing of components of the CEO's compensation contract in response to entrenchment as predicted under the optimal contracting theory of compensation contracts. The findings of this study are almost entirely consistent with the managerial power theory, according to which entrenchment at IPO causes a permanent shift in bargaining power, which enables CEOs to influence compensation contracts in their favor.

This qualitative study explores the unconscious life of four children diagnosed with Obsessive-Compulsive Disorder (OCD) specifically related to selfconcept, personality, and psychopathology using a case study approach. A review of literature on childhood OCD is presented and the study is located within a psychodynamic theoretical framework. Findings indicate that the children are emotionally maladjusted, with high levels of anxiety and psychopathology. They have low self-esteem and poor body images, mostly tending towards immaturity. Two of the children have personality disturbances (neurotic, hysterical personalities). All the children have disturbed superegos (harsh or neurotic). Although their symptoms are currently mild, and some have ceased, analysis suggests they have been repressed and continue to affect them. They are sexually preoccupied and conflicted due to the unsuccessful resolution of the Oedipus complex. They have poor impulse control and considerable anger and aggression (mostly overt). They experience their environment as unstable and frightening and have anxieties about physical injury and being watched. The boys have regressed sex drives and homosexual tendencies, and have not identified with their fathers. The girls have identified with their mothers but experience masturbation guilt and blocked sexual drives, causing anxiety and moodiness. The children are all highly defended and escape from feelings of helplessness, inadequacy, and isolation, and discharge anxiety and aggressive instincts by using the defenses of undoing, reaction formation, acting-out, fantasy (sometimes violent), projection, displacement, and intellectualisation. Their strong dependency needs suggest fixation in the oral stage of psychosexual development. They tend towards self-directed aggression and depression. Most have family histories of mood disorders (particularly depression), and obsessions linked to fears of economic hardship due to parental illness or death. Most have histories of anxiety disorders or anxiety-related problems, and family histories of anxiety disorders and/paternal OCD. They all experienced a personally traumatic event precipitating the onset of OCD.

As plantas, produtores da base das cadeias tróficas, apresentam diversos tipos de defesas contra a ação de consumidores, os herbívoros, podendo ser defesas físicas, químicas e bióticas. Nas defesas bióticas, plantas fornecem recursos alimentares (e.g. néctar extrafloral) e/ou moradia para predadores que em troca podem fornecer proteção contra herbívoros. Assim, a partir de comportamentos agressivos e/ou de patrulha, formigas são consideradas os principais protetores de plantas. Nessa perspectiva, a presente dissertação buscou investigar a influência que o néctar extrafloral tem sob a interação formiga-planta em uma área de Cerrado. O estudo foi realizado na Reserva Ecológica do Clube Caça e Pesca Itororó de Uberlândia, no município de Uberlândia, MG, em uma área com fitofisionomia de cerrado sentido restrito. A espécie de planta utilizada neste estudo foi Qualea multiflora (Vochysiaceae), uma das espécies mais abundantes do Cerrado, a qual apresenta nectários extraflorais (NEFs) na base do pecíolo foliar e nas inflorescências. Nossas hipóteses principais foram: a) que formigas visitantes dos NEFs de Q. multiflora impactam positivamente a planta, reduzindo a ação de herbívoros; b) que essas interações formigas-plantas são modificadas ao longo do desenvolvimento fenológico das folhas das plantas; c) que diferentes níveis de herbivoria nas plantas produzem também diferentes reações nas formigas visitantes; e d) que diferentes estruturas das plantas apresentam diferentes níveis de defesas. Os resultados demonstrados no Capítulo 1 comprovam que a herbivoria foliar em Q. multiflora foi baixa e similar nos diferentes estágios de desenvolvimento da folha, mostrando que as defesas expressas pela planta são eficientes. Das três defesas foliares avaliadas durante o desenvolvimento foliar, observou-se que a densidade de tricomas apresenta pico de efetividade no início do desenvolvimento, a defesa biótica (produtividade dos NEFs) apresenta pico de efetividade no período intermediário do desenvolvimento, e a dureza foliar apresenta pico de efetividade no período em que a folha já está adulta. Esses resultados comprovam a eficiência da variação temporal nas defesas foliares de Q. multiflora, o que interfere diretamente na interação formiga-planta. No Capítulo 2, foi mostrado que NEFs localizados em inflorescências produzem néctar mais volumoso e energético que atrai maior quantidade de formigas comparado ao néctar produzido pelos NEFs foliares. A produtividade e a atratividade dos NEFs, assim como o forrageamento de formigas, também foram afetados por variações na herbivoria (simulada experimentalmente). Esses resultados demonstram que Q. multiflora sincroniza suas defesas foliares ao longo do tempo garantindo a proteção contra herbívoros e que essas defesas (como evidenciado para defesa biótica) podem ser alteradas de acordo com o valor e probabilidade de ataque de suas estruturas. / Plants, producers of food chains, have different types of defenses against action of consumers, herbivores, which can be physical, chemical and biotic defenses. In biotic defenses, plants provide food resources (e.g. extrafloral nectar) and/or shelter for predators, which in turn may provide protection against herbivores. Thus, from patrol and/or aggressive behavior, ants are considered main plants protectors. From this perspective, the present work aimed to investigate the influence that extrafloral nectar has under ant-plant interaction in an area of Cerrado. The study was conducted in Reserva Ecológica do Clube Caça e Pesca Itororó de Uberlândia, in Uberlândia, MG, in an area with cerrado stricto sensu vegetation. The plant species used was Qualea multiflora (Vochysiaceae), one of the most abundant species of Cerrado, which has extrafloral nectaries (EFNs) at the base of leaf petiole and in inflorescences. Our main assumptions were: a) EFNs visitors ants of Q. multiflora positively impact the plant reducing the herbivore action; b) these ants-plants interactions are modified along the phenological development of plant leaves; c) different herbivory levels in plants produce different reactions in visitors ants; and d) different plant structures have different defenses levels. Results presented in Chapter 1 show that foliar herbivore in Q. multiflora was low and similar to different stages of leaf development, showing that expressed plant defenses are effective. Of the three foliar defenses evaluated during leaf development, it was observed that density of trichomes presents effectiveness peak in early development, biotic defense (EFNs productivity) in intermediated period of development and leaf toughness in the period in which the leaf is adult. These results show the efficacy of temporal variation in foliar defenses in Q. multiflora, which directly affects ant-plant interaction. In Chapter 2, it was shown that EFNs located in inflorescences produce nectar more quantitative and qualitative, which attract large amount of ants, than EFNs located in leaves. EFNs productivity and attractiveness, as well as ants foraging, were also influenced by herbivory variation (experimentally simulated). These results show that Q. multiflora synchronizes its leaf defenses over time ensuring protection against herbivores and that these defenses (as evidenced for biotic defense) can be changed according to value and attack probability of their structures.

As sessile organisms, plants evolved a plethora of defenses against their attackers. Given the role of plants as a primary food source for many organisms, plant defense has important implications for community ecology. Surprisingly, despite the potential to alter entire food webs and communities, the factors determining plant investment in defense are not well-understood, and are even less understood considering the numerous symbiotic interactions in the same plant. Legume-rhizobia symbioses engineer ecosystems by fixing nitrogen from the atmosphere in trade for plant photosynthates, yet connecting symbiotic resource exchange to food web interactions has yet to be established. Here I test how rhizobia influence plant defense and tritrophic interactions in lima bean (Fabaceae - Phaseolus lunatus L.): a model plant in chemical ecology research characterized by a broad range of different defenses. Examining suites of traits among lima bean genotypes, highly cyanogenic cultivars and wild type plants (high cyanotypes) produce more hook-shaped trichomes, as a putative combined approach of chemical and mechanical defenses, forming defense syndromes to protect against multiple feeding guilds (Chapter 2). Testing costs that may have contributed to forming tradeoffs among strategies, high cyanotypes show reduced fitness under plant-plant competition relative to low cyanotypes, but when challenged with herbivory, high cyanotypes fitness reductions are no longer evident (Chapter 3). Young leaves, not reproductive organs, are the most cyanogenic lima bean organ, and removal quantitatively decreases fitness, supporting assumptions that the most valuable tissues will be most highly defended (Chapter 4). Testing the degree to which nitrogen-fixing rhizobia contribute to cyanogenesis, high cyanotypes form more nodules than low cyanotypes. Quantitative relationships between nodule number and plant traits highlight the role symbiotic investment plays a role in plant defense and nutritive phenotype, while simultaneously, genotypically-determined levels of defense shape plant investment in symbiosis (Chapter 5). Interestingly, traits that trade off by cyanotype (i.e. high cyanogenesis but low indirect defense) reflect the patterns in plants with nitrogen-fixing rhizobia. Rhizobia-inoculated lima beans show reduced indirect defenses, recruiting fewer parasitoid wasps (Chapter 6) and predatory ants (Chapter 7). Examining plant-ant attraction in greater detail, ants prefer headspace regions above EFN droplets, corresponding with species-specific differences in suites of volatiles, indicating EFN, like floral nectar, can be scented to manipulate insect behavior (Chapter 8). Overall, understanding when investing in traits to recruit predators is more effective than investing in defensive chemistry, and how particular ecological contexts, such as symbioses can influence the outcome of defense allocation strategies remains a fascinating area of research. Determining the mechanisms underlying why rhizobia and other belowground microbial symbionts influence their host plants' above ground interactions, whether plants traits affected by symbiotic microbes are simply a function of the costs and benefits from resource exchange, or whether symbionts can influence the success of primarily direct versus indirectly defended plants is an important question for understanding complex trophic systems and connecting to agricultural implications for more effective biological pest control.

Climate change is ecologically and socially complex, deemed the most important issue of our generation. Through this dissertation I have approached climate change research through an interdisciplinary perspective, investigating how this phenomenon will affect marine ecological systems, how we can better develop experimental systems to answer ecological questions, and how we can effectively educate about this issue. In Chapter 2, I provided accessible alternatives for researching the effects of climate change (elevated temperatures and pCO2) on marine ecosystems. I designed, built, and troubleshooted two accurate and inexpensive climate-controlled experimental systems capable of maintaining target conditions: a temperature-controlled system and an ocean acidification system. The temperature-controlled system was designed to manipulate experimental tank temperatures indirectly by controlling the temperature in a surrounding water bath, which buffered fluctuations and resulted in a high level of control. The ocean acidification experimental system was designed to elevate normally fluctuating pCO2 levels by a constant factor, which allowed pCO2 to fluctuate as expected in natural environments and made it more ecologically relevant than active pCO2-controlled systems. In Chapter 3, I experimentally tested the morphological responses of southern ribbed mussels Geukensia granosissima to two simultaneous stressors (elevated temperatures and the presence of water-borne predation cues from blue crab Callinectes sapidus) and if any effects of these treatments led to differences in handling times by predatory crabs. Bivalves may become more susceptible to predation as increased temperatures decrease the protection afforded by their shells, but few studies have tested the effects of elevated temperatures on inducible defenses in bivalves. Results showed that chronic heat stress can have detrimental morphological effects on intertidal mussels. Mussels reared in elevated temperatures manifested elongated shell shapes, exhibited a disruption of the predator effect on inducible defenses, and experienced decreased predator handling times. The observed responses to elevated temperatures could make southern ribbed mussels more vulnerable to predation. In Chapter 4, I experimentally tested the morphological responses of southern ribbed mussels to elevated pCO2 levels and the presence of water-borne predation cues from blue crabs, and if these effects led to differences in handling times by predatory crabs. Elevated pCO2 can have negative effects on bivalves’ morphology and physiology, but the consequences of these effects on predator-prey interactions are still unclear. I found that adult southern ribbed mussels’ inducible defenses were not affected by a medium-term exposure to elevated pCO2. Mussels grew more in shell length and width as a response to predation cues, independent of pCO2 conditions. However, and unexpectedly, mussels reared under elevated pCO2 exhibited greater growth in shell width independent of predator treatment, driving mussels reared in the presence of a predator under elevated pCO2 conditions to develop rounder shapes. On average, these effects on mussel morphometrics did not affect crab handling times, but mussels reared in the presence of a predator under elevated pCO2 conditions had highly variable handling times. It is important to consider the complexity of animal physiology, morphology, and interspecies relationships when making deductions on predator-prey relationships in a changing ocean. In Chapter 5, I analyzed the effectiveness of using an interdisciplinary approach to climate change education. Literature suggests that an interdisciplinary instructional framework in an outdoor setting, using tools from the experiential, active, and inquiry- and place-based learning approaches, as well as the socioscientific issues pedagogical framework, would be an excellent approach for climate change education. I found that students: increased their content knowledge on climate change causes and consequences, exhibited a deeper understanding of climate change through the words they used to describe it, and corrected common climate change misconceptions. This work can serve as an example for the development of effective climate change programs that uses already available instructional materials with intentional interdisciplinary goals. Our search to understand how marine ecosystems will cope with a changing climate has emphasized emerging issues in the way we gather data, the questions we seek to answer through research, and how we translate science of social importance to the public. Through this dissertation I strove to seek the answers to some of these questions and provide feasible solutions to some of the problems in climate change research and education through an interdisciplinary approach. As science continues to move towards answering questions of concern for both science and society, science research is moving towards more interdisciplinary approaches. This dissertation is an example of how this can be an efficient and comprehensive approach.

Despite the role played by the South East Treaty Organisation (SEATO) in the defence of Western interests in that region during the Cold War, there has to date been no scholarly attempt to examine the development and performance of the organisation as a military alliance. This thesis is thus the first attempt to do so and as such seeks to take advantage of the recent release of much SEATO-related official material into the public domain by Western governments. This material throws new light upon SEATO???s aims and achievements, particularly in regard to the first ten years of its existence. Because SEATO was eventually rendered irrelevant by the events of the Second Indochina War (1965-1975) a popular perception has arisen that it was always a ???Paper Tiger??? lacking in substance, and thus easily dismissed. This thesis challenges this assumption by examining SEATO???s development in the decade before that conflict. The thesis analyses SEATO???s place in the wider Cold War and finds that it was part of a rational and consistent response within the broader Western strategy of containment to deter, and if need be, defeat, the threat of communist aggression. That threat was a very real one for Southeast Asia in the aftermath of the First Indochina War and one that was initially perceived in terms of the conventional military balance of power. This focus dominated SEATO???s strategic concepts and early contingency planning and rightly so, as an examination of the strength and development of the PLA and PAVN during this period demonstrates. SEATO developed a dedicated military apparatus, principally the Military Planning Office (MPO), that proved itself to be perfectly capable of providing the level of co-ordination and planning needed to produce a credible SEATO deterrent in this regard. SEATO enjoyed less success with its attempts to respond to the emergence of a significant communist insurgent threat, first in Laos then in South Vietnam, but the alliance did nonetheless recognise this threat and the failure of SEATO in this regard was one of political will rather than military doctrine. Indeed this thesis confirms that it was the increasingly disparate political agendas of a number of SEATO???s members that ultimately paralysed its ability to act and thus ensured its failure to meet its aims, at least insofar as the so-called ???Protocol States??? were concerned. But this failure should not be allowed to completely overshadow SEATO???s earlier achievements in providing a modicum of Western-backed stability and security to the region from 1955-1965.

For decades scientists believed that herbivory had minimal impact on freshwater ecosystems. We now know that herbivory in freshwater systems equals or exceeds herbivory in terrestrial and marine systems. In extreme cases, herbivores can change clear, macrophyte dominated ecosystems into turbid plankton dominated ecosystems. Even though research on plant-herbivore interactions in freshwater systems has increased, there is still much that is unknown. This thesis is comprised of four studies investigating freshwater plant-herbivore interactions across multiple spatial scales. The first study investigated how induced chemical defenses in Cabomba caroliniana suppress herbivore consumption and growth as well as how this herbivore-generated change in plant chemistry affects the growth of plant associated microbes. At the spatial scale of individual ponds or lakes, consumers that induce their host plants may also be indirectly affecting other consumers and microbial pathogens via changes in this shared resource. The second study moves to an ecosystem scale and investigates how exotic versus native apple snails may impact Everglades' habitats. We investigated plant preference, consumption, growth and conversion efficiencies in the singly native apple snail to occur in the U.S. (Pomacea paludosa) versus four introduced species (P. canaliculata, P. insularum, P. haustrum and P. diffusa). We found that even though plant preferences are similar, invasive snails tend to eat more, grow more rapidly, and sometimes more efficiently than natives. This suggests that invasive species could have a large impact on the environment, especially the abundance of submerged plants. The third study investigated how palatability of freshwater plants varies with latitude (i.e. geographic scale). Increased herbivory at lower latitudes is hypothesized to select for increased plant defenses, which has been shown to be true for tropical forests, salt marshes, and seaweeds. When we contrasted eight confamilial plants collected in Indiana versus Southern Florida, three of four herbivores significantly preferred northern plants. When we evaluated a second set of plants collected from Indiana versus Central Florida, only one of three herbivores preferred the northern plants. Overall, our results suggest a preference for northern plants, but the strength of this relationship was variable. We hypothesize that this variability may be driven by 1) local variance in herbivore pressure that creates variance in plant defenses, and/or 2) the effect of winter length on the survival and feeding rate of herbivores. The final study expanded to a world scale, and investigated herbivore preference for native vs exotic plants. We found that both N. American crayfish and S. American snails preferred exotic plants over confamilial natives, despite responding to different plant characteristics. The single species of apple snail that occurs in N. American showed no preference for native or exotic plants from a N. American perspective, but instead exhibited preferences that correlated with its history of evolution in S. America. As the N. American species is a sister species of the S. American snails, feeding by the N. American snail appears more affected by its S. American lineage than its recent history in N. America. This suggests that phylogenetic legacy will affect choices of the herbivore as well as resistance or susceptibility of plants.