Bt maize expressing Cry1Ab was approved for release in South Africa for control of Busseola fusca (Fuller) (Lepidoptera: Noctuidae) and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) in 1998. During 2012, a stacked Bt maize event, expressing Cry2Ab2 + Cry1A.105, was also approved for control of these abovementioned pests. The aim of this study was to determine the effects of two Bt maize events expressing Cry1Ab (MON810 and Bt11) and a Bt maize event expressing Cry2Ab2 + Cry1A.105 (MON89034) on selected lepidopteran non-target pest species and certain lepidopteran stem borer species in South Africa. Results from previous studies and this study will provide information regarding efficacy of Bt maize against pests which have not been evaluated yet. Insects with significance in maize agro-ecosystems in South Africa as well as the rest of Africa, were prioritised and laboratory bioassays were conducted to evaluate the effect of Bt maize against these selected target and non-target pest species. Studies were conducted on three stem borers C. partellus, Eldana saccharina and Sesamia calamistis and three nontarget lepidopteran pest species Agrotis segetum, Helicoverpa armigera and Spodoptera exempta. Results showed that MON810 maize was not effective against A. segetum larvae feeding on maize seedlings. Differential levels of survival were observed between two A. segetum populations on MON89034 with a population from Polokwane showing survival on the stacked maize event. No S. exempta 1st instar larvae survived on MON810 and MON89034 but 3rd instar larvae survived on MON810 maize. Helicoverpa armigera larvae survived on ears of MON810 maize plants but not on events MON89034 or Bt 11. Results further indicated that C. partellus larvae were highly susceptible to these three Bt maize events. Larval survival of S. calamistis was recorded for larvae feeding on MON810 and Bt11 maize ears but not on MON89034 maize ears. Bt maize during the vegetative growth stages therefore effectively controlled C. partellus, S. calamistis and E. saccharina but the latter two species was not effectively controlled when feeding on ear tissue. This study provides important information on the effects of Bt maize on the most important non-target pest species of maize in sub-Saharan Africa. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

We consider modified versions of a cell population model for periodic chemotherapy treatment of tumors. These models contain both proliferating and quiescent cells, and treats the transitions between the two types of cells. Our models are defined by replacing the loss term function, μ(t, c), in Webb's model by a constant. This corresponds to having a constant infusion of the drug rather than having a periodic chemotherapy treatment. We compare our results with those of Webb who shows that shorter periods of treatment are advantageous.

The grammar of modification is highly complex and raises numerous questions about the relation between meaning and form. This dissertation provides a study of how modified noun phrases are interpreted and examines the consequences of these results for the syntax of the nominal domain. The discussion centers on two types of modification: superlatives and stacked modification. The data comes primarily from English, but other languages are also discussed. There is initial evidence that the main claims hold across a wide range of languages. The common view on superlatives is that they have two types of interpretations which are the result of a scope ambiguity and that the contrast between them needs to be captured by means of syntactic devices. Contra this standard approach I propose a saliency theory of superlatives which claims that there is no categorical difference between these two interpretations and where the variation in the meaning of superlatives is purely pragmatic in nature. Under this view the meaning of superlatives is a function of the properties of the surrounding discourse and the context-sensitivity of superlatives is subsumed to the more general phenomenon of context-dependency in the interpretation of natural language quantifiers. The saliency theory differs from other analyses that have adopted a discourse approach in that the so-called comparative reading does not depend on the presence or interpretation of focus. Previous approaches to multiple adjectives analyzed their order in terms of the semantics of individual adjectives. I present a new set of data which shows that this is insufficient and propose an explanation that takes into account the meaning of the whole nominal phrase. This result has consequences for how the architecture of grammar should be conceived. In particular, it shows that principles of syntactic well-formedness can sometimes be sensitive to compositional semantic interpretation, as well as pragmatic information. This is in contradiction to many contemporary approaches to grammar where the semantic component has no influence on the syntactic one. / text

Paraguay has a long history of foreign involvement in its rural economy, dating back to even before the War of the Triple Alliance in the 1880’s. Whether it was yerba mate production or timber extraction, Paraguay’s rural activities were largely funded and run by foreign interests, with little room for participation by smallholders. With the growth in production of Genetically Modified (GM) soy, Paraguay continues to follow the same model for development, one of export-oriented agriculture produced primarily with foreign capital. The expansion GM soy in San Pedro, Paraguay is meeting with considerable resistance, though, as smallholders and landless workers claim that the use of the broad spectrum herbicide, glyphosate, threatens their health, land and livelihoods. The contentious debate that has sprung up around this issue has polarized Paraguayan society and oversimplified the problems facing Paraguay’s rural development society. The over-politicization of the conflict has eliminated the space for nuance in finding solutions and room for dialogue. / text

No description available.

Darbo tikslas: buvo ištirti ekologinių ūkių ūkininkų žinias ir požiūrį į genetiškai modifikuotus organizmus, jų produktus bei galimą riziką aplinkai ir žmonių sveikatai. Metodika: tyrime dalyvavo atsitiktinai atrinkti Lietuvoje sertifikuotų ekologinių ūkių ūkininkai, 18 metų ir vyresni nei 70, turintys įvairią ūkininkavimo patirtį. Apklausoje dalyvavo 188 vyrai ir 114 moterų. Vertinome, kaip atsakymai priklausė nuo ūkininkų amžiaus, ūkininkavimo patirties ir lyties. Skirtumą laikėme reikšmingu, jeigu p <0,05. Rezultatai: darbe buvo tirtos šiandien sparčiai populiarėjančių ekologinių ūkių ūkininkų žinios apie genetiškai modifikuotus produktus, jų poveikį aplinkai ir žmonių sveikatai; palygintas požiūris į GMO su požiūriu į tradicinius ūkius, naudojančius GM pašarus; palyginta ekologiškai ūkininkaujančių žmonių nuomonė su kitų visuomenės apklausų duomenimis apie požiūrį į GM produktus ir jų galimą riziką. Tyrimas parodė, kad 62,5 proc. vyrų ir 51,7 proc. moterų gerai žino kokiuose produktuose yra GMO ingredientų. 60,2 proc. vyrų ir 39,8 proc. moterų teigė, kad pirko tokių maisto produktų. 93 proc. ūkininkų nuomone, GMO ir GM produktai gali būti kenksmingi žmonių sveikatai. 97,3 proc. ūkininkų nuomone, produktai, kurie gaminami iš gyvūnų, šeriamų GM pašarais taip pat turi būti ženklinami. Dalis ūkininkų sutiktų nebesiversti ekologiniu ūkiu ir augintų GM kultūras, jeigu būtų mokamos EB subsidijos. Išvados: apklausa parodė, kad didelė dalis ekologinių ūkių ūkininkų žino... [toliau žr. visą tekstą] / Aim of the study: to explore the organic farming knowledge and attitudes to genetically modified organisms and their products and the potential risk to the environment and human health. Methods: organic farmers of 18 years and older than 70, with a range of farming practices randomly selected from certified organic farms participated in the study. The survey involved 188 men and 114 women. We evaluated how the answer depends on the farmers' age, farming experience, and gender. The difference was considered as meaningful if p <0.05. Results: the knowledge of organic farmers about genetically modified products and their impact on the environment and human health were tested; the knowledge and approach on GMO were compared with attitude to conventional farms using GM feed; the organic farmers approaches were paralleled with other people's opinion polls on public attitudes to the genetic modified products and their potential risks. 62, 5 % of males and 51, 7 % of females know about products containing GMOs ingredients. 60, 2 % of males and 39, 8 % of females argued that they purchased the products containing ingredients of genetically modified organisms. 93 % of organic farmers indicated that the GMOs and GM products can be harmful to human health. Up to 97, 3 % farmers are of the opinion that meat from GM feed feeding animals should also be labeled. The investigation has revealed that EU subsidies could influence farmers to move from organic to conventional farm... [to full text]

The debate around genetically modified food and crops has proved to be complex and far-reaching, involving diverse stakeholder groups and many issues. Although the extent of global uptake of GM crops has been substantial (23 countries and 114.65 million hectares by 2007), it is significant that four countries are responsible for 86% of all GM plantings, and that a number of key food markets (for example the EU and Japan) remain largely "GM-free‟. This suggests that there is reluctance on the part of many countries to embrace GM technology. There are likely many reasons for this, but one significant issue is that of the perception of the risks associated with the technology. There is a distinction between risk that exists in the world and that can be measured (objective risk) and risk that is perceived by an individual to exist and that is constructed by them based on their values and preferences. When technical measurement of actual risks is not possible, peoples‟ own perceptions of risks become important. This thesis aims to investigate the topic of risk perceptions associated with GM food and crops. Different stakeholder groups have been targeted, and a range of methodologies from a variety of disciplines have been employed to investigate what factors can be shown to influence risk perception. A range of factors were identified from existing literature, as having potential impact on risk perceptions. A number of these were investigated, some of which were found to have some influence on levels of risk perception. Results demonstrate that factors influencing peoples‟ perceptions of risk relating to GM food and crops, include the uncertainty associated with the technology, and trust in regulators, policy makers and others with control over the future development of the technology. Other factors found to be important to levels of risk perception held by different stakeholder groups, were a range of socio-demographic and cultural variables, the relationship between perceived risks and benefits, the equity of impacts, and the influence of third parties. There are a number of implications for the development of the GM debate arising from the findings. First, as there are socio-demographic and cultural factors linked to the perceptions of risk associated with GM technologies in food and agriculture, it is important to recognise that different people will react differently to the technology. Specifically, results from this thesis show that it may be that men, those who are more highly educated, those with a less ecocentric worldview, and those living in urban areas, are likely to respond more favourably to targeted promotional campaigns. As regards the farming community, results show that the first farming adopters are likely to be those who are both owners and tenants, not in an urban fringe location, potato growers, and not barley growers. Second, this thesis provides evidence that third parties are particularly important to farmers, thus it is crucial to recognise that there is potentially a long chain of action and reaction amongst many different stakeholders and actors impacting on farmers' levels of risk perception, and hence willingness to adopt the technology. Third, results from this research demonstrate that the linked issues of the relationship between risks and benefits, and the equity of (positive and negative) impacts, require that all stakeholders are content that they will receive a share of the benefits (if any) to be derived from the technology, and that neither they nor any other group of stakeholders are unduly impacted by the risks or negative impacts (if any) of the technology. Important here is the recognition that perceptions are as important as actual impacts. Fourth, the issue of trust has been shown by the results obtained by this research to be extremely important to peoples' perceptions of risk. It can be concluded that trust is of wider social and political importance that relates to the need to ensure greater democratisation of decision-making in order to re-establish trust in authorities. In the case of GM food this may require a rethinking of the EU legislation relating to the technology. This also relates to point below about the delivery of messages and education. Information sources must be trusted by those at whom the messages are aimed. More importantly though, if people are to trust decision making processes, there needs to be stakeholder involvement at an early stage of decision making, that allows some impact on decisions taken. In the case of the GM debate it may indeed be too late as decisions about the technology, its applications, the regulatory processes and its inclusion within the food chain are well established. Perhaps the best that can be hoped for is that lessons will be learnt and applied to future technology developments of relevance to the food chain, such as, nano-technology. Finally, this thesis has shown that uncertainty is central to peoples' perceptions of risk. This could be addressed through a combination of additional research into what is uncertain to people, the impacts and implications of the technology, more effective dissemination of existing knowledge, and impartially delivered messages and education strategies from trusted sources that address the concerns that people have about the technology. Importantly however there must be an acknowledgement that uncertainty is not restricted to "knowledge deficit‟ but encompasses the scientific uncertainties inherent within the technology, and is framed by the social and cultural values of those whose views are considered. This thesis uniquely targeted diverse groups and employed a combination of different methods from a variety of disciplines. By doing this the study has increased understanding of the views of two groups (campaigners and farmers) who are crucial to the uptake of the technology, and who are seldom researched in the area of attitudes to GM technologies. The diversity of groups, methods and disciplines brought together in this thesis is important because the issue of GM has proved to be complex and far-reaching, and previous discussions of risk perceptions have been complex and disjointed. All groups investigated here are stakeholders in the process, and as such their views and concerns relating to risk perceptions of GM technologies ought to be taken into consideration.

Vegetation plays an important role in the partitioning, transport and fate of hydrophobic organic contaminants (HOCs) in the environment. This thesis aimed at addressing two key knowledge gaps in our understanding of how plants exchange HOCs with the atmosphere: (1) To improve our understanding of the uptake of HOCs into, and transfer through, leaves of different plant species which can significantly influence the transport and fate of HOCs in the environment; and (2) To evaluate an experimental approach to measure fluxes of HOCs in the field. The methods presented in papers I, II and III contribute to increasing our understanding of the fate and transport of HOCs in leaves by offering straightforward ways of measuring mass transfer coefficients through leaves and partition ratios of HOCs between leaves, leaf lipids and lipid standards and reference materials like water, air and olive oil. The passive dosing study in paper III in particular investigated the role of the composition of the organic matter extracted from leaves in determining the capacity of the leaves to hold chemicals and found no large differences between 7 different plant species, even though literature data on leaf/air partition ratios (Kleaf/air) varies over 1-3 orders of magnitude. In paper IV we demonstrated that the modified Bowen ratio method can be extended to measure fluxes of persistent organic pollutants (POPs) if the fluxes do not change direction over the course of the sampling period and are large enough to be measured. This approach thus makes it possible to measure fluxes of POPs that usually require sampling times of days to weeks to exceed method detection limits. The experimental methods described in this thesis have the potential to support improved parameterization of multimedia models, which can then be evaluated against fluxes measured in the field using the modified Bowen ratio approach. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.</p>

Bimetric theory is an extension to general relativity that introduces a secondary symmetric rank-two tensor field. This secondary spin-2 field is also dynamical, and to avoid the Boulware-Deser ghost issue, the interaction between the two fields is obtained through a potential that involes the matrix square-root of the tensors. This square-root “quantity” is a linear transformation, herein referred to as the square-root isometry. In this work we explore the conditions for the existence of the square-root isometry and its group properties. Morever we study the conditions for the simultaneous 3+1 decomposition of two fields, and then, in terms of null-cones, give the (local) causal relations between fields coupled by the square-root isometry. Finally, we show the algebraic equivalency of bimetric theory and its vielbein formulation up to a one-to-one map relating the respective parameter spaces over the real numbers. / Den bimetriska teorin är en utökning av den allmänna relativitetsteorin som introducerar ett sekundärt symmetriskt tensorfält av rang-två. Det här sekundära spin-2 fältet är också dynamiskt, och för att undvika Boulware-Deser spöke, erhålls vaxelverkan mellan de två fältena genom en potential som er baserad på kvadratrotsmatris av två tensorfält. Den “kvadratroten” är en linjär avbildning som kallas kvadratrotsisometri. I detta arbete utforskas förutsättningar för existensen av kvadratrotsisometrin och ges dess egenskaper i termer av gruppteori. Därutöver utforskas förutsättningarna för den samtidiga 3+1 dekompositionen av två tensorfält och sedan, i termer av ljuskoner, ges de (lokala) kausala relationerna för tensorfält kopplade genom kvadratrotsisometrin. Slutligen bevisas den algebraiska ekvivalensen mellan den bimetriska teorin och dess vielbein formulering upp till en bijektiv relation mellan respektive parameterutrymmen över de reella talen. / <p>Summarizes the results from the project done between March 2014 and November 2014.</p>

Master of Science / Department of Agricultural Economics / Timothy Dalton / Previous research on small-scale farmers in KwaZulu-Natal, South Africa indicates that certain genetically modified maize seed types improve production efficiencies and increase net returns (Regier 2012). Yet despite the substantiated advantages, not all farmers have adopted genetically modified maize. The purpose of this research is to identify the determinants of adopting certain types of genetically modified maize over traditional or conventional hybrid maize for 184 small-holders in two villages in KwaZulu-Natal, South Africa. Previous adoption studies use socioeconomic characteristics of the farmer as well as farm-level production characteristics to determine the probability that a farmer will implement an improved agricultural technology. While many studies employ a binomial approach to adoption, this study tests the probability of adopting three different GM varieties—the insect resistant Bt maize, the herbicide tolerant Roundup Ready® maize, and the stacked trait BR maize. Furthermore, the model is enhanced by farmers’ open-ended explanations of their perceptions on genetically modified maize and of the major production constraints they face. Following results from previous adoption studies, this research tests three hypotheses in a three different model structures. The first hypothesis tests whether farmers are more likely to adopt if they have greater financial means to cover higher expected production costs. This is tested by variables measuring off-farm employment and expected production costs. The second hypothesis tests whether farmers with less labor availability are more likely to choose maize with the herbicide tolerant technology, either the Roundup Ready® or stacked BR maize, which reduce the need for weeding. The final hypothesis is whether there are differences in the determinants of adoption that differentiate GM adopters into three distinct categories. These hypotheses are tested in three model structures that test the binary probability of adopting GM maize over non-GM, the probabilities of adopting each maize variety separately, and the intensity of adoption. The first finding is that many non-adopters have greater access to income and are more likely to sell a portion of their yield than are many farmers who adopted, especially in comparison to those who plant RR maize. Also, BR farmers are more likely to report input expenses as a major constraint in their adoption decision. Results for the second hypothesis show that those who planted either RR or BR maize did in fact have less family labor available, used less total labor, and used a greater proportion of family to hired labor. Finally, there are differences in the determinants for geographic site, education, self-sufficiency in maize supply, number of family members working off-farm, and whether households planned to sell any of their maize yields. This indicates that adoption should be considered according to each genetically modified trait.