Thesis (Ph. D.) -- Lincoln University, 2006.

Thesis (MPhil)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The aim and function of this paper is to provide a balanced account of how the media, international and South African, have dealt with the issue of genetically modified organisms (GMOs). A selection of interviews, presentations, articles, transcripts and published reports forms the background of this interpretation, and offers insight into the history of the technology, the major role players, the legislation required and implemented, the question of environmental accountability, and the power of the media's influence. It addresses aspects of the causal relationship between the media and public understanding, and the subsequent power of the consumer as manifested by the perception of risk. The central theme of genetic engineering conjures up a variety of meanings and applications, and the plethora of available information is evaluated in an attempt to develop informed understanding for reporters covering the many dimensions of this development within the arena of science and technology. / AFRIKAANSE OPSOMMING: Die doel van hierdie verhandeling is om 'n ewewigtige oorsig te verstrek van hoe die media - Suid-Afrikaans sowel as internasionaal - die kwessie van geneties gemodifiseerde organismes gehanteer het. 'n Seleksie onderhoude, aanbiedinge, artikels, transkripsies, en gepubliseerde verslae vorm die basis van hierdie interpretasie, en verskaf 'n insig in die geskiedenis van die tegnologie, die belangrike rolspelers, nodige en géimplementeerde wetgewing, die vraag van omgewingstoerekenbaarheid, en die mag van die media se invloed. Dit spreek aspekte aan van die kousale verwantskap tussen die media en begrip deur die algemene publiek, en die daaropvolgende mag van die verbruiker, soos dit duidelik word in hulle insig in en begrip van die risiko-faktor. Die sentrale tema van genetiese modifisering bring te voorskyn 'n verskeidenheid betekenisse en aanwendings; en 'n oorsig van die massa beskikbare inligting word hier aangebied in 'n poging om aan verslaggewers ingeligte begrip aan te bied van die veelsydige omvang van die ontwikkeling van genetiese modifisering in die gebied van wetenskap en tegnologie.

Nos últimos anos, a irradiação por micro-ondas tem sido cada vez mais usada na síntese de varias moléculas orgânicas, devido a uma série de vantagens que essa nova tecnologia apresenta. Até o momento, existem poucos estudos sobre polimerizações assistidas por micro-ondas e menos ainda sobre a modificação de polímeros usando essa nova fonte de energia. Polímeros heterocíclicos contendo anéis azóicos, como o tetrazol possuem interesse acadêmico e comercial devido as suas várias aplicações. Nesta Dissertação foi estuda a modificação química da poliacrilonitrila pela incorporação em sua cadeia polimérica de 10% de grupos tetrazol empregando-se a irradiação de micro-ondas e o método convencional (térmico). Foram utilizados um forno de micro-ondas doméstico e um reator de micro-ondas monomodo nas reações assistidas por micro-ondas. As reações em reator foram realizadas em vaso aberto, em solução (DMF) ou em massa, sendo variado o tempo e a temperatura reacional, bem como a potência do equipamento. Os copolímeros produzidos foram caracterizados por espectroscopia na região do infravermelho (FTIR) e os teores de grupos tetrazol incorporados na PAN foram determinados por titulometria de neutralização. A poliacrilonitrila foi modificada quimicamente com sucesso tanto no forno doméstico quanto no reator de micro-ondas, como foi verificado pela sua análise de FTIR. Pela determinação do grau de incorporação de grupos tetrazol nos polímeros concluiu-se que, para a reação em solução, nas temperaturas mais elevas, bem como em uma potência maior, o teor de heterocíclico incorporado no polímero está muito próximo do valor obtido pelo método convencional. Já as reações conduzidas em massa apresentaram graus de incorporação inferiores as das feitas em solução. / In recent years, microwave irradiation has been increasingly used in the synthesis of various organic molecules, due to a number of advantages that this technology presents. To date, few studies on polymerization assisted by microwave and even less about the modification of polymers using this new source of energy. Polymers containing heterocyclic ring azoles such as tetrazole have academic and commercial interest due to their various applications. This thesis has been studying the chemical modification of polyacrylonitrile by its incorporation into the polymer chain, 10% of tetrazole groups employing the irradiation of microwave and conventional method (thermal). We used a domestic microwave oven and a reactor monomode microwave to assisted reactions in the microwave. The reactions were performed in reactor open cup in solution (DMF) or in bulk, and varied the reaction time and temperature, and power equipment. The copolymers were characterized by infrared spectroscopy (FTIR) and the concentrations of tetrazole groups incorporated into the PAN were determined by neutralization titration. The polyacrylonitrile was chemically modified with success both at home and in the oven microwave reactor, as verified by his analysis of FTIR. By determining the degree of incorporation of tetrazole groups in the polymers it was concluded that, for the reaction in solution at higher temperatures, as well as a higher power, the content of heterocyclic incorporated into the polymer is very close to the value obtained by the conventional method. The reactions were conducted in mass lower degree of incorporation of the solution made.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23453号 / 理博第4747号 / 新制||理||1680(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 向山 信治, 准教授 De Felice Antonio , 教授 萩野 浩一 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

No description available.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24869号 / 理博第4979号 / 新制||理||1711(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 向山 信治, 准教授 樽家 篤史, 教授 橋本 幸士 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

No description available.

We begin by reviewing special and general relativity in such a way as to smoothly transition into current research. We present the variational formalism of general relativity as well as the extension into the palatini formalism. This allows us to develop a theory on a metric affine manifold rather than the standard manifold in general relativity. We present a generalized action intended to replace the Einstein Hilbert action in general relativity and derive some consequences thereof. The modified field equations are derived by varying this action using the Palatini approach. The corresponding differential equations are solved thereby establishing the equivalence between the modified action and the standard action with a cosmological constant. Furthermore the metric due to a spherically symmetric distribution of mass is found and applied in calculating the bending of light in the curved space. It is deduced that no difference between the modified action and the original Einstein Hilbert action is observed thereby implying that the experiment involving the bending of light around the sun in 1919 in no way distinguishes between our modification and the original approach by Einstein and Hilbert.

Yes / In this study, we prepared chitosan (Cs_P) nanofibers (NFs) membrane by electrospinning. The Cs_P NFs membrane was then chemically functionalized (CsF) by a novel stepwise chemical process. The CsF NFs membrane was electrospray with TiO2 nanoparticles (NPs) to prepare the CsF_Coa NFs membrane. A second NFs membrane with embedded TiO2 NPs (Cs_Co) was also prepared by electrospinning. The TiO2 NPs, Cs_P, CsF s, CsF_Coa NFs, and Cs_Co NFs membranes were analyzed by standard spectroscopic, microscopic, X-ray, and thermal methods. Fourier transform infrared (FTIR) analysis confirmed the incorporation of the new functional group into the Cs structure. X-ray photoelectron spectroscopy (XPS) data confirmed the FTIR results and the fabrication of the CsF NFs membrane. Scanning electron microscope (SEM) micrographs showed a smooth morphology for the Cs_P NFs membrane and a denser morphology for the CsF NFs membrane (NFs swelled with functionalization). The SEM micrographs also showed a dense cloud of TiO2 NPs on the surface of the Cs_Coa NFs membrane. Transmission electron microscope (TEM) showed that the particle size of TiO2 NPs varied between 20 and 35 nm and tended to be spherical. The X-ray diffraction (XRD) pattern confirmed the existence of the anatase phase of the TiO2 NPs. The presence of TiO2 in the Cs_Coa and Cs_Co NFs membranes was also confirmed by energy-dispersive x-ray spectroscopy (EDX). Surface profilometry confirmed an increase in the surface roughness of the CsF and Cs_Coa NFs membranes. Brunauer–Emmett–Teller (BET) analysis revealed that the isotherms and hystereses for all NFs membranes were of the IV and H3 types, respectively, corresponding to mesopores and slit pores. The higher photocatalytic activity of the Cs_Coa NFs membrane (89%) compared to the Cs_Co NFs membrane (40%) was attributed to a balance between the short band gap, high surface roughness, and lower surface area.

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