Drug use and misuse among young people in Australia has caused concern throughout the community and has prompted nationwide action to address the problem. One component of intervention strategies with young people is drug education. Drug education in Australia represents an international philosophy of prevention and takes a harm minimisation approach to intervention. One strategy that has had international success in the area of drug education with young people, and that has been used effectively in health education in Australia since the 1970s, is peer education. Peer drug education involves young people conducting drug education sessions with their peers. An example of peer drug education in Australia is the Teenagers Teaching Teenagers' (Triple T) program, conducted in the Australian Capital Territory (ACT). Evaluations and descriptions of peer drug education programs tend to focus more on outcomes pertaining to program recipients and fail to explore in detail the specific experience of peer leaders. Existing research on the experience of peer leadership does not explore in detail the personal experience of leaders, that being the effect of peer leadership training and duties on leaders' personal perceptions of drugs, their behaviour with drugs and their own feelings and skills. This thesis explores the personal experience of a group of peer leaders who participated in the Triple T program in 1994. It considers their perceptions of the program at the time of training and then goes on to explore the impact of this experience on their formulation of ideas about drugs to the present day. The thesis is a qualitative project which utilises in-depth interviewing and focus groups to gather data and then presents a thematic analysis of participant response. The thesis asks two research questions, 1. What do young men and women involved in the Triple T program take from the experience of peer leadership training and duties? 2. In what way does the Triple T' experience appear to contribute to the development of drug related ideas of these young people in the two years following involvement in the program? The findings suggest that the participants gained information, skills and personal development from the training and generally found it to be a positive experience. However, participants distanced themselves personally from a substantial amount of the training content and did not personally reflect on the training content to any great extent at the time of training. Training processes and some aspects of leadership duties more personally affected them, although again there was personal distancing from this part of the program. In exploring the findings there was difficulty determining the influence of the training experience due to participant reluctance to attribute influence to any one source on the formulation of ideas. Instead, participants describe a complex interaction of influences on the formulation of ideas about drugs and a process which involves maintaining control, upholding the notion of informed choice and incorporating ideas about drugs into the formation of an adult identity. Influences on these ideas include the training, actual experiences with drugs and observations of others. The thesis exploration suggests that being involved in peer drug education does impact on peer leaders but this experience was not personalised to any great degree at the time of training. However, in the following two years, participants called on the training information as well as other influences as they formed their ideas about drugs. The thesis raises some issues of how to maximise leaders' personal connection to the peer drug education process, if this is in fact a desired outcome of peer education. It also suggests the need for further research into the experience of peer leaders who seem to have remained the least considered party in the peer education movement.

Drug use and misuse by young people is a problem and concern in the Australian and Australian Capital Territory (ACT) communities. There are concerns regarding illicit and licit drugs but licit drug use has been identified as the major area of concern. Young people in the ACT reflect the drug use/misuse patterns and trends of other states. Commonly used drugs by young people are alcohol, tobacco, cannabis and analgesics. Strategies to address the problem of drug use/misuse by young people include intervention and community drug education programs. Peer drug education (as an example of community drug education), trains young people as peer educators to implement drug education programs with younger age groups. A case study analysis based on qualitative, naturalistic and new paradigm research is the research method used in this thesis. An eclectic model of drug education including key components from a variety of drug education models provides a comprehensive overview of peer drug education. The literature review showed the complexity of influences on drug use/misuse. These influences relate to individual, peer, parental and family, community and societal factors. Peer drug education is generally recognised as an effective drug education strategy. Peer drug education programs (Triple T: Teenagers Teaching Teenagers) were conducted in the ACT from 1988-1990. Reports documenting these programs (including evaluation data) and a literative review are the main data analysed for the case study. The case study analysis of five ACT peer drug education programs and one interstate program showed the key planning issues for effective peer drug education were: collaborative decision making as a central concept; detailed planning and liaison with target groups; established structures within schools and communities to support the trained peer educators; team work and small group work as intrinsic and extrinsic factors within the program; clarification of responsibilities and roles of all personnel involved in the program; and facilitators/leaders with attributes and qualities that encourage peer drug educators as social change agents. Analysis of data from the case study reports showed young people can be effective peer drug educators. Residential programs are preferred over non-residential programs. Peer drug education programs are effective in both school and community agencies. The literature review and analysis of reports also indicated that peer drug education needs to focus on establishing positive norms in groups of young people. Collaborative decision making and positive role modelling assist in the establishment of these norms. Peer drug education links to the wider changes occurring in education and health settings. Peer drug education is about collaborative decision making, social justice, development of key competencies and social change. This thesis confirmed the complexity and dynamic nature of peer drug education and there were many questions raised for further research from the literature review and analysis of program reports.

Approximation theory is a fundamental tool in order to study the representation theory of a ring R. Roughly speaking, it consists in determining suitable additive or abelian subcategories of the whole module category Mod-R with nice enough functorial properties. For example, torsion theory is a well suited incarnation of approximation theory. Of course, such an idea has been generalised to the additive setting itself, so that both Mod-R and other interesting categories related with R may be linked functorially. By the seminal work of Beilinson, Bernstein and Deligne (1982), the derived category of the ring turns out to admit useful torsion theories, called t-structures: they are pairs of full subcategories of D(R) whose intersection, called the heart, is always an abelian category. The so-called standard t-structure of D(R) has as its heart the module category Mod-R itself. Since then a lot of results devoted to the module theoretic characterisation of the hearts have been achieved, providing evidence of the usefulness of the t-structures in the representation theory of R. In 2020, following a research line promoted by many other authors, Saorin and Stovicek proved that the heart of any compactly generated t-structure is always a locally finitely presented Grothendieck categories (actually, this is true for any t-structure in a triangulated category with coproducts). Essentially, this means that the hearts of D(R) come equipped with a finiteness condition miming that one valid in Mod-R. In the present thesis we tackle the problem of characterising when the hearts of certain compactly generated t-structures of a commutative ring are even locally coherent. In this commutative context, after the works of Neeman and Alonso, Jeremias and Saorin, compactly generated t-structures turned out to be very interesting over a noetherian ring, for they are in bijection with the Thomason filtrations of the prime spectrum. In other words, they are classified by geometric objects, moreover their constituent subcategories have a precise cohomological description. However, if the ascending chain condition lacks, such classification is somehow partial, though provided by Hrbek. The crucial point is that the constituents of the t-structures have a different description w.r.t. that available in the noetherian setting, yet if one copies the latter for an arbitrary ring still obtains a t-structure, but it is not clear whether it must be compactly generated. Consequently, pursuing the study of the local coherence of the hearts given by a Thomason filtration, we ended by considering two t-structures. Our technique in order to face the lack of the ascending chain condition relies on a further approximation of the hearts by means of suitable torsion theories. The main results of the thesis are the following: we prove that for the so-called weakly bounded below Thomason filtrations the two t-structures have the same heart (therefore it is always locally finitely presented), and we show that they coincide if and only they are both compactly generated. Moreover, we achieve a complete characterisation of the local coherence for the hearts of the Thomason filtrations of finite length.