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This study aims: 1) To quantify the factors affecting the changes of site water status of the high sand tailings, 2) To investigate the growth and physiological responses of <I>Acacia mangium </I>and <I>A. auriculiformis </I>to the fluctuations of site water status on high sand dunes, and 3) To identify characteristics which may allow the trees to adapt to and survive on high sand tailings. In both shade and open plots on sand tailings, diurnal air water deficits would be anticipated particularly in sunny days and late afternoon in cloudy days. The results from dipwell showed that the main source of soil water supply to the sand tailings is solely dependent on the rainfall and not from surrounding mining pools. Furthermore, at 6 d after rainfall <37 mm, sand tailings at 0-15 cm depth had low sand suction showing soil water deficit to plant uptake. Hence, the rainfall distribution would determine the growth of acacias in sand tailings. Dry periods significantly reduced (P<0.05) the shoot length and stem diameter growth rates and leaf area of both acacias. Dry periods also significantly increased leaf and branch number shedding rates of both acacias. Generally, shading did not improve the growth rates of both acacias in dry periods but significantly delayed leaf shedding of the two acacias in dry periods. <I>A. auriculiformis </I>had significantly higher shoot length and stem diameter growth rates as the result of higher leaf and shoot numbers. The superiority of <I>A. auriculiformis</I> compared to <I>A. mangium </I>in adapting to high sand tailings was explained by its growth patterns that had characteristics of drought avoidance, and/or tolerance. Greater vegetative growth was observed in <I>A. auriculiformis </I>than <I>A. mangium </I>in wet periods. The effects of atmospheric and soil water fluctuations on some physiological responses of the two species were also examined.

The main aim of this work was to investigate the nature, distribution and transmissibility of tetracycline resistance (Tc^R) genes among ruminant anaerobic bacteria. Two Tc^R rumen strains of <I>Butyrivibrio fibrisolvens,</I> 1.230 and 1.23, were able to transfer the resistance phenotype to the type strain, 2221^R although a third Tc^R strain, 1.210, could not. PCR amplification of 16S rDNA sequences showed that the three isolates were phylogenetically distinct from the recipient strain, but related to each other. Hybridisation work suggested the presence of two chromosomal Tc^R determinants among the <I>B. fibrisolvens </I>isolates. All three strains contained a non-transferable <I>tet</I>(O) gene, 100% identical at the nucleotide level with <I>tet</I>(O) from <I>S. pneumoniae. </I>The mobile Tc^R determinant present in strains 1.230 and 1.23, proved to be a novel ribosome protection <I>tet </I>gene, <I>tet</I>(V), whose gene product shares only 68% amino acid identity with its closest relatives, TetO/TetM and has G+C content considerably higher than that of other <I>B. fibrisolvens </I>genes. <I>tet</I>(V) was also identified in two Australian rumen <I>B. fibrisolvens </I>strains, in the rumen anaerobes <I>Selenomonas ruminantium </I>and <I>Mitsuokella multiacidus, </I>and in a pig isolate of <I>M. multiacidus. </I>These results provide evidence for gene transfer between obligate and facultative anaerobes from different gut ecosystems and different geographical locations. PFGE demonstrated that mobile chromosomal elements 40-50 kb in size, Tn<I>B1230 </I>and Tn<I>B123, </I>with preferred insertion sites in the recipient genome mediated the transfer of <I>tet</I>(V) in <I>B. fibrisolvens. </I>No homology was found between Tn<I>B1230</I> and regions from Tn<I>916</I> and Tn<I>5253. </I>Tn<I>B1230</I> is not associated with <I>tet</I>(V) in the other bacterial strains, suggesting that a diverse range of elements carry the gene in different bacteria. Although <I>tet</I>(V) is chromosomally encoded in the majority of the strains examined, there is some evidence that the gene may be located in a plasmid in <I>S. ruminantium </I>FB32 and FB34.

In the first year, two upland rice varieties (Azucena and Bala), were screened for root response to drought at the West Africa Rice Development Association (WARDA), Cote d’Ivoire, in two fields of slightly different soil penetration resistance (PR) characteristics.  Changes in soil PR and soil water content were monitored during the drought period.  Root density and depth were significantly greater for Azucena than Bala, and on the irrigated plots compared to the droughted plots, although no consistent site differences in root density were observed.  At each site, on the droughted subplot, soil PR quickly increased near the surface (0-30 cm) in response to reduction in soil water content and soil matrix potential caused by root water extraction.  It is likely that this increase in PR would have either prevented or reduced the rate of downward growth of new roots entering or growing within this layer.  Under these conditions, varietal differences in root response to impedance would be important for drought avoidance. In the second year, also at WARDA, a mapping population based on a cross between Azucena and Bala were tested in two fields of contrasting soil physical properties and QTL for root density at 35 cm were identified.  There was no agreement between sites.  Site characterisation prior to field screening revealed the two sites to be very different in terms of soil texture and water relations.  These site differences would have restricted root growth in different ways and are likely to be reasons behind the lack of agreement in root density QTL between sites. In the third year, near-isogenic lines (NILs) differing only in single or multiple root growth QTL were screened in fields at the International Rice Research Institute (IRRI), Philippines, in soils of lower mechanical impedance than sites used at WARDA.  No major differences were observed for root density indicating the importance of interaction between root traits and the environment when considering contribution to drought resistance.

The following key words were used: resistance, change, renewal, conflict, change management, resistance management, restructuring. All economies, and especially an economy like that of The New South Africa, depend on a well-educated, adaptable and continuously teaching work force to generate and implement change and innovation in schools. This requires a high quality and standard of education. Furthermore, education has a critical role to play in attempts to develop and maintain successful democratic societies. To address these objectives, order in the practical teaching situation is a prerequisite. Educators play a key role in creating quality and order in the practical teaching situation. Quality and order in education mean that the education process and outcomes must realise the best potential of the learners and meet the expectations of the community. Other factors such as resources may also contribute, but educators are mainly responsible for such quality and order since these aspects are rooted in their knowledge, skills and dedication. At present large numbers of pupils leave school with a school record of failure and without sufficient knowledge, understanding and competence to pursue successful careers. One of the reasons for this sense of failure is the almost complete absence of order in some schools since educators are resisting change which is brought about in the education system. There are many reasons for the apparent resistance to change. It is believed that educators can, to a certain extent, be regarded as a significant factor (perhaps a key factor) causing lack of order and discipline in schools, because of lack of support from the education department in meeting the needs of educators to enable educators to be productive. The management of resistance to change by school principals in Sedibeng-West (D8) was investigated in this study. Changes are continually occurring on all levels of a rapidly developing community. The school principal, as education manager, should be trained in a firm variety of skills, whlch will enable him to implement the management of resistance to change efficiently. Examples of large-scale changes that occurred in education during the past six years are the implementation of Curriculum 2005 and the transformation of Model C schools. It would therefore appear that it might be sensible to focus on reducing educators' resistance to change as part of a strategy to re-establish and promote order in education. The aim of this research centred on the following questions: How can the concept "resistance" be interpreted to create positive attitudes amongst educators to accept change in the education system? What is the role of principals as managers of resistance to change? Firstly, a literature study was undertaken to ascertain the nature of resistance to change, as well as methods and models according to which resistance to change can be managed. Findings from the literature study point to a number of aspects of resistance to change that play a decisive role in the management of change. These include factors giving rise to resistance to change, types of resistance to change, manifestation of resistance to change and reaction phases of resistance to change. Secondly, an empirical investigation was undertaken to investigate the degree and way in which school principals manage resistance to change and how educators' attitudes can be changed to accept change positively. For this purpose structured questionnaires were used. / Thesis (M.Ed.)--North-West University, Vaal Triangle Campus, 2004.

There are currently more than 33 million people worldwide who are infected with HIV-1 despite development of novel treatments and knowledge of prevention strategies. Within the Pumwani area of Nairobi, Kenya there is a group of commercial sex workers who are highly exposed to HIV-1. A small subset of these women have been classified as resistant to HIV-1 infection as they remain HIV un-infected despite as many as 60 unprotected sexual exposures to HIV each year. A better understanding of such a natural model of HIV resistance would be invaluable to inform the development of a protective HIV vaccine or microbicide. Globally, heterosexual transmission of HIV across mucosal surfaces is responsible for the bulk of new infections and thus it is important to examine both the macro and the micro environments of the vaginal mucosa in efforts to determine what enhances and what thwarts HIV-infection. Previous studies have shown elevated levels of RANTES, a natural ligand for the dominant HIV co-receptor CCR5, in cervicovaginal secretions of HIV-resistant women. Additionally, a novel HIV-inhibitor, Trappin-2 was previously shown to be elevated in cervicovaginal secretions of HIV-resistant women. To test the hypothesis that RANTES and Trappin-2 in cervicovaginal fluid are important mediators of HIV resistance we will: 1) measure RANTES in a much larger group of women from the Pumwani cohort, and 2) measure Trappin-2 levels in samples taken at different time points, and 3) correlate Trappin-2 levels in cervicovaginal fluid with biological confounding variables, and 4) investigate whether SDF-1 plays a role in HIV-disease progression in HIV-positive women.

Inducible chomosomal AmpC β-lactamase (AmpC) is present in many Gram-negative opportunistic human pathogens. Expressed in response to β-lactam antibiotics, AmpC is an enzyme that can deactivate an extended spectrum of β-lactam antibiotics and thereby promote bacterial survival. Inducible chromosomal ampC is associated with ampR, a gene that encodes a LysR-type transcriptional regulator that suppresses ampC expression in the absence of β-lactam exposure. Together, ampR and ampC form a divergent operon with overlapping promoters to which the AmpR protein binds and regulates the transcription of both genes. AmpR induces ampC expression by interacting with 1,6-anhydro-N-acetylmuramyl peptide, an intermediate of peptidoglycan recycling that is generated by a glycoside hydrolase encoded by nagZ. Given the role of NagZ and AmpR in the AmpC induction pathway, the structure and function of these proteins were investigated to understand the molecular basis for how they participate in AmpC production. The crystal structure of NagZ from Vibrio cholerae was determined in complex with the glycoside hydrolase inhibitor PUGNAc (O-(2-Deoxy-2-N-2-ethylbutyryl-D-glucopyranosylidene)amino-N-phenylcarbamate) to 1.8 Å resolution. Since PUGNAc also inhibits functionally related human enzymes, the structure of the enzyme was also determined in complex with the NagZ selective PUGNAc derivatives N-butyryl-PUGNAc (2.3 Å resolution) and N-valeryl-PUGNAc (2.4 Å resolution). These structural studies revealed the molecular basis for how 2-N-acyl derivatives of PUGNAc selectively inhibit the bacterial enzyme NagZ. The effector binding domain of AmpR from Citrobacter Spp. was determined to 1.83 Å resolution and lead to the identification of a putative effector molecule binding site. In vivo functional analysis of site directed mutants of AmpR containing amino acid substitutions at the base of the putative binding pocket verified its role in AmpR function. A protocol was subsequently devised to purify milligram quantities of soluble full-length AmpR. Biochemical and biophysical analysis, including non-denaturing mass spectrometry and small angle X-ray scattering, revealed that the purified full-length protein is tetrameric and specifically binds ampC promoter DNA. In summary, this research provides the basis for the development of small-molecules that could specifically block the activity of these proteins to suppress AmpC β-lactamase production during β-lactam therapy.

During the 19th century, British imperialism and Canadian colonialism aspired to subdue, subjugate and assimilate the Plains Cree (cf. Tobias 1992:148). This particular brand of colonialism employed Indian policy – a form of structural violence—rather than military force. I argue that structural violence was both legitimized and supported by cultural violence. The distortion of history is a prime example of cultural violence. That Canada followed an honorable and just policy in its dealings with Plains Indians (cf. Tobias 1983:519) is the contemporary residue of a myth created during colonial times in political circles to justify the dispossession of Aboriginal lands and resources. In the 19th Century, Cree leaders, Piapot and Big Bear, who were perceived as threats to Canadian “progress,” were routinely publicly maligned. The “official” historical literature often uncritically reflected these prevalent ethnocentric views of the day. Critical historical theorists, however, have offered a number of opposing views. This thesis focuses attention on the literature which takes a more critical and culturally informed approach to Canadian nation-building. It places a discussion of structural constraints at the centre of an exploration of the strategies Plains leaders used to resist a variety of Indian policies including reserve settlement.

This thesis is a phenomenological, qualitative study of student resistance and seeks to contribute to an understanding of the relationship between community, communication, and resistance by exploring the social contexts that provide meaning to the resistant behaviours of six graduates of an independent Christian school. In doing so, this thesis takes a transactional perspective of resistance – a perspective that recognises students as having multiple and shifting identities, and schools as being complex, social settings which contextualises student resistant behaviours. Integral to this perspective is a communicative potential of resistance that can be used as a means of signalling, generating, and building dialogue among the various groups of people who make up the school community. This study suggest that school need to go beyond seeing resistance as purely an expression of political statements or an engagement in power struggles and consider how resistance can be a potential communicative act. Specifically, resistance signals a need for reflection and dialogue on the ways in which the ideals of that community are both intended and experienced.