Diss.--Geschichtswissenschaften--Marburg, 1974. / Bibliogr. p. 286-306. Index.

Zugl.: Mainz, Universiẗat, Diss., 1991/92.

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The relationship between the types of construction of high rise caged layer houses and insulation damage produced by the lesser mealworm was examined. Polyurethane insulation which had heavy-weight paper glued to its surface and was installed with tape to seal off the seam between the insulation boards had no infestations. Structures with concrete block pit walls had lower insulation infestations than those houses with wooden walls forming the pits. Houses with a support structure set on top of the concrete block pit wall had lower infestations than houses built with the support structure set directly into the earth. The insulation installed nearest the pit was the most severely infested, and infestation intensity was inversely proportional to insulation height above the manure pit. Damage in extruded polystyrene insulation resulted in a substantial loss of volume of material in the corner areas of the insulation panels, and caused a significant reduction in insulating quality. Observations were made on the effect of manure moisture and poultry house construction materials on lesser mealworm dispersal behavior. Larvae and adults preferred manure habitats of 30 and 40% moisture, and dispersal from the manure significantly increased when manure moisture was increased to levels of 50 and 60%. Larvae climbed a significantly greater distance up a vertical wooden surface than up a vertical concrete block surface under field conditions. Results indicate that structures built with wood pit walls are predisposed to infestations, and that fluctuating manure moisture levels in these houses can indirectly contribute to accelerated infestation by driving the larvae from the manure pits into the insulation. Insecticide sprays, plastic films, paint barriers applied to the surface of extruded polystyrene, and different types of insulation were evaluated for lesser mealworm resistance. In a laboratory study, tetrachlorvinphos and pirimiphos-methyl sprayed on extruded polystyrene produced greater than 90% mortality in larval and adult populations up to 71 weeks postapplication. Larvae were unable to penetrate either chlorpyrifos-impregnated or non-insecticidal polyethylene films. Infestation intensity was inversely proportional to insulation cell size. Effective treatments identified under field conditions were permethrin and pirimiphos-methyl sprays, and two formulations of chlorpyrifos-impregnated latex paint. Insulation materials with a cell size of 1.5 mm were resistant to lesser mealworm field populations. / PH. D. / incomplete_metadata

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Late instar larval Alphitobius diaperinus initiated tunneling damage to polystyrene insulation in search of protected pupation sites. Adult females oviposited upon the surface of the styrofoam but early instar larvae left the styrofoam soon after hatching. Within twenty days, large numbers of adults moved into the styrofoam, expanding the tunnels and depreciating the panels' suitability as pupation sites for the late instar larvae. No oviposition occurred within the tunnels. All lifestages of Alphitobius diaperinus were found to be cannibalistic. Although preliminary tests show that adult mealworms will consume house fly late instar larvae and prepupae, no significant predation of the house fly by A. diaperinus could be detected under simulated natural conditions at the population density tested. Wettable powder formulations of permethrin and carbaryl when sprayed upon styrofoam were comparable in residual activity. Residual activity of both compounds was less when applied to unpainted plywood. The emulsifiable concentrate formulation of permethrin proved to be ineffective. Regression slopes from topical application studies reveal that tetrachlorvinphos may be the material of choice against A. diaperinus because there is less chance of the lesser mealworm developing resistance to tetrachlorvinphos than with either permethrin or carbaryl. Tetrachlorvinphos also showed longer residual effectiveness against A. diaperinus as a surface spray on styrofoam and plywood than did permethrin or carbaryl. / Master of Science

Doctoral thesis submitted in fulfilment of the requirements for the Degree of Doctor of Philosophy to the Department of Development Studies, Faculty of Humanities at the University of the Witwatersrand, Johannesburg, South Africa, 2016. / Abstract This study examines the dynamics of power and the significance of local environmental knowledge in natural resource management in Zimbabwe’s communal areas. It uses a case study of Bulilima District, broken down into into 3 components (Wards) for manageability of the study, to analyse the power configurations and the role played by local environmental knowledge in influencing decision-making processes among actors in the district with regard to mopane worms (Imbrasis beilina is the scientific name while icimbi is the vernacular name) and mopane woodlands (Colophospermum mopane is the scientific name while iphane is the vernacular name). It examines the significance of local environmental knowledge, i.e. indigenous knowledge and knowledge that developed as a result of a combination of knowledges from different ethnic groups and modern science. The study further examines the dynamics of the gendered nature of mopane worms and woodlands tenure regimes by putting under the spotlight the spaces and places where men and women interact, use and exert control over mopane worms and woodlands. It places history at the centre of our understanding of contemporary power dynamics and helps us to appreciate the importance of how local environmental knowledge has changed over time. To this end, the study argues that some of the contemporary conflicts over resources have their roots in the colonial era when the colonial government appropriated land from the locals and introduced discourses and practices such as conservation. Furthermore, it argues and demonstrates that the state is a critical player in determining access, use and control of natural resources. Based on rich ethnographic data collected by means of critical observations, in-depth interviews, narratives, and archival data, as well as aided by a brief survey, the study concluded that natural resource governance is a complex phenomenon in developing states. Power and knowledge play significant roles in influencing access, use and control of mopane worms and woodlands. Furthermore, while some locals still possess indigenous knowledge, practices and belief systems related to natural resource management, these are now less significant in influencing decisions on natural resource management. Indeed, the interplay of knowledge and power in resource management sees scientific culture and outside knowledge taking precedence over local forms of knowledge in the management of natural resources in the district. Key words: power, local environmental knowledge, indigenous knowledge, ZANU PF, natural resource management, access, mopane worms and woodlands, Bulilima, Zimbabwe / GR2017

Student Number : 9607275H - MSc dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / Internet worms are capable of quickly propagating by exploiting vulnerabilities of hosts that have access to the Internet. Once a computer has been infected, the worms have access to sensitive information on the computer, and are able to corrupt or retransmit this information. This dissertation describes a method of predicting Internet instability due to the presence of a worm on the Internet, using data currently available from global Internet routers. The work is based on previous research which has indicated a link between the increase in the number of Border Gateway Protocol (BGP) routing messages and global Internet instability. The type of system used to provide the prediction is known as an autoencoder. This is a specialised type of neural network, which is able to provide a degree of novelty for inputs. The autoencoder is trained to recognise “normal” data, and therefore provides a high novelty output for inputs dissimilar to the normal data. The BGP Update routing messages sent between routers were used as the only inputs to the autoencoder. These intra-router messages provide route availability information, and inform neighbouring routers of any route changes. The outputs from the network were shown to help provide an early warning mechanism for the presence of a worm. An alternative method for detecting instability is a rule-based system, which generates alarms if the number of certain BGP routing messages exceeds a prespecified threshold. This project compared the autoencoder to a simple rule-based system. The results showed that the autoencoder provided a better prediction and was less complex for a network administrator to configure. Although the correlation between the number of BGP Updates and global Internet instability has been shown previously, this work presents the first known application of a neural network to predict the instability using this correlation. A system based on this strategy has the potential to reduce the damage done by a worm’s propagation and payload, by providing an automated means of detection that is faster than that of a human.

As computer and communication networks become prevalent, the Internet has been a battlefield for attackers and defenders. One of the most powerful weapons for attackers is the Internet worm. Specifically, a worm attacks vulnerable computer systems and employs self-propagating methods to flood the Internet rapidly. The objective of this research is to characterize worm attack behaviors, analyze Internet vulnerabilities, and develop effective countermeasures. More specifically, some fundamental factors that enable a worm to be designed with advanced scanning methods are presented and investigated through mathematical modeling, simulations, and real measurements. First, one factor is an uneven vulnerable-host distribution that leads to an optimal scanning method called importance scanning. Such a new method is developed from and named after importance sampling in statistics and enables a worm to spread much faster than both random and routable scanning. The information of vulnerable-host distributions, however, may not be known before a worm is released. To overcome this, worms using two sub-optimal methods are then investigated. One is a self-learning worm that can accurately estimate the underlying vulnerable-host distribution while propagating. The other is a localized-scanning worm that has been exploited by Code Red II and Nimda worms. The optimal localized scanning and three variants of localized scanning are also studied. To fight against importance-scanning, self-learning, and localized-scanning worms, defenders should scatter applications uniformly in the entire IP-address space from the viewpoint of game theory. Next, a new metric, referred to as the non-uniformity factor, is presented to quantify both the unevenness of a vulnerable-host distribution and the spreading ability of network-aware worms. This metric is essentially the Renyi information entropy and better characterizes the non-uniformity of a distribution than the Shannon entropy. Finally, another fundamental factor is topology information that enables topological-scanning worms. The spreading dynamics of topological-scanning worms are modeled through a spatial-temporal random process and simulated with both real and synthesized topologies.

Internet-worms are a major threat to the security of today¡¦s Internet and cause significant worldwide disruptions, a huge number of infected hosts generating overwhelming traffic will impact the performance of the Internet. Network managers have the duty to mitigate this issue . In this paper we propose an automated method for detecting Internet-worm in large network based on NetFlow. We also implement a prototype system ¡V FloWorM which can help network managers to monitor suspect Internet-worms activities and identify their species in their managed networks. Our evaluation of the prototype system on real large and campus networks validates that it achieves pretty low false positive rate and good detecting rate.