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The retentive power of selected dental luting cements has been investigated in-vitro with regard to the effects of taper, temporary cementation and recementation. A standard test method has been developed from measurements of clinically observed tapers and cementation pressures achieved, and account has been taken of the dimensions of human teeth. These observations have indicated a mean clinical taper of 17^o to 30^o and an initial pressure of 6 kg typically reduced to 3 kg. The order of retention of the various cements has been found to be composites> glass-ionomers/polycarboxylates > zinc phosphate> EBA cement. Prior use of eugenol-based temporary cements appears to have no adverse effect, except possibly in the case of resin-based composites in conjunction with a volatile cleaning/drying agent. These studies indicate that the effect of taper may be more complex than the literature suggests. In contrast to the accepted view of a monotonic relationship between retention and taper, the current study indicates that for most cements there may in fact be an optimum taper in the range 7^o to 15^o. The reason for this is unclear. Recementation appears to have no adverse effect on retention. A separate clinical survival study ranked the cements in the order glass-ionomer/polycarboxylate> zinc phosphate> EBA, in full agreement with the in-vitro data.

Through the Convention on Biological Diversity and the various approaches of governments and NGOs, Species Action Plans (SAPs) have become key in framing conservation action for threatened species. Despite their wide deployment in conservation, there have been no global comparative studies of SAP structure and content and how they are created, reviewed, and utilised. Species reintroductions often form a key part of SAPs and species recovery actions. Although species reintroductions are frequently assessed in terms of their outcomes, it is often unclear what 'success' or 'failure' mean and what factors might drive them. I aimed to establish (1) the key components and outputs of Species Action Plans, and how they compare across regions, taxa, and time; (2) how conservation practitioners utilise and perceive Species Action Plans; and (3) the factors that are influencing species reintroduction successes and failures. I did this by applying a mixed method approach utilising questionnaires and analysing case studies to establish practitioner perceptions, and patterns and relationships within the data. Results highlight the variation in SAP content across regions and time, finding that SAPs vary in structure and components across regions but less so across taxa, and that SAPs have evolved across time in line with scientific evidence, practice, and the associated development of guidance. Of note were the increased inclusion in recent years of success criteria and indicators, and that post-SAP reviews and evaluations were scarce and contained little information on SAP implementation or the success of actions in relation to indicators or monitoring. The development, value, utilization, and evaluation of SAPs was researched using data from an online questionnaire targeted at conservation practitioners. Conservation practitioners' perceptions of SAPs were positive, indicating that SAPs are highly valued and utilised widely. In relation to SAP content and structure, four principal components considered core to a SAP were identified. These were: (1) Strategic action and threats; (2) Species status; (3) Implementation, monitoring, and financial plans; and (4) Project vision. An evaluation of species reintroduction success was undertaken based on a global analysis of 341 case studies. It identified geographical and taxonomic variations in success rates and factors relating to partnerships and support, and habitat and release site as influential in success or failure. Having too many programme goals also appeared to be linked to a negative outcome. In summary, SAPs are extremely valuable but could be improved by having more focussed components that include priority actions, and separate implementation and monitoring plans. Having clear outcomes, measurable indicators or success criteria within SAPs and seeking practitioner feedback allows actions to be assessed and adapted. A stronger focus on partnerships and support, and habitat may improve reintroduction success.

Nature conservation is a challenging profession. Professionals may face many obstacles before reaching their goals. Conservation work has been described as cognitively challenging, emotionally demanding, and physically straining and, at times, open to dangerous encounters caused by wildlife and people. Furthermore, the field of conservation is ever-changing, both by advances in its or associated disciplines and by rapid changes at a global political, social, and ecological level. Therefore, this doctoral research had as central research question: which role can capacity development have in optimising the work performance of conservation professionals? This study's results, arising from a mixed methods investigation, show that job resources, especially those provided by the organisation, are crucial for professional development and resilience building processes, and for optimising work performance. By thematically analysing the data of 22 interviews and 2 focus groups, organisational resources that were found to be linked to positive psychological states (e.g. experiences of energy, work engagement) were recognition and appreciation, and opportunities for growth and development. Results concerning work resources that were associated with positive psychological states were related to autonomy (i.e. freedom in work) and task significance (i.e. meaningful work). The strengths of these relationships were tested on a dataset obtained through 561 questionnaire respondents and by means of structural equation modelling. Quantitative data results confirmed the central role of job resources in reducing stress and burnout and increasing work engagement, which, in turn, positively influenced work performance. Overall, the results have highlighted the importance of considering both job demands and job resources when optimising work design and work environment for conservationists to maintain energy and perform their jobs well. Furthermore, individual processes of professional learning and resilience building can enhance thriving in the workplace in uncertain and rapidly changing environments.