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This dissertation is an exhibition of applied microeconomic theory in political and resource economics. As three examples, I investigate three different questions, respectively: Does polarization of beliefs always intensify political gridlock in collective decision making? Will input-efficiency improvement in water use, e.g., adoption of more-efficient irrigation technologies and investment in water-conveyance systems, definitely decrease the demand for water-storage capacities, e.g., dams and reservoirs? Is collectivism, rather than individualism, generally helping society overcome the collective action problem? Using the game-theory or stochastic-control approach, I theoretically challenge conventional wisdoms about these questions, and illustrate the empirical relevance of my challenges, qualitatively or quantitatively, in different contexts, e.g., the Chinese transition from the planned economy, World War II and Operation Market--Garden, the irrigation water-inventory management of the California State Water Project, and the histories of collective action in China and Europe.

AbstractWe model how corruption erodes state power, that is, the state's ability to keep its apparatus under control in crises. Under a general assumption about fat-tailed risk of crisis, we show that given strong fiscal capacity, the head of the state will control local corruption at such a level that its power is secured; given weaker capacity, the state will over-tolerate corruption to retain officials, risking control in crises; moreover, a state may be trapped with too weak fiscal capacity, rampant corruption, and the state losing control in any real crisis, while having little incentive to invest in fiscal capacity. By developing historical narratives, we show that these theoretical results are consistent with experience from the Roman Empire, New Kingdom of Egypt, Ming China and many other powerful states in history.

How do corruption and the state apparatus interact, and how are they connected to the political and economic dimensions of state capacity? Motivated by historians' analysis of powerful empires, we build a model that emphasizes the corrosive effect of corruption on state power. Under general assumptions about fat-tailed risk, we show that, if fiscal capacity is strong, then the optimal response for the head of the state apparatus will be an endogenous lexicographic rule whereby local corruption is maintained at such a level that no erosion of state power is tolerated. Comparative statics shows the impacts of additional risk of crisis on corruption tolerance as well as the complementarity between personalistic rule and corruption. Implications of corruption at the head of the state apparatus are also analyzed. If fiscal capacity is not sufficiently strong, however, the state will have to over-tolerate corruption to retain its affiliates, risking its control in crises. Our model predicts that the correlation between state's political stability and corruption is non-monotonic across different levels of fiscal capacity, and this prediction is robustly consistent with recent cross-country panel-data.

Predictive risk models using general practice (GP) data to predict the risk of hospitalisation have the potential to identify patients for targeted care. Effective use can help deliver significant reductions in the incidence of hospitalisation, particularly for patients with chronic conditions, the highest consumers of hospital resources. There are currently no published validated risk models for the Australian context using GP data to predict hospitalisation. In addition, published models for other contexts typically rely on a patient's history of prior hospitalisations, a field not commonly available in GP information systems, as a predictor. We present a predictive risk model developed for use by GPs to assist in targeting coordinated healthcare to patients most in need. The algorithm was developed and validated using a retrospective primary care cohort, linked to records of hospitalisation in Victoria, Australia, to predict the risk of hospitalisation within one year. Predictors employed include demographics, prescription history, pathology results and disease diagnoses. Prior hospitalisation information was not employed as a predictor. Our model shows good performance and has been implemented within primary care practices participating in Health Care Homes, an Australian Government initiative being trialled for providing ongoing comprehensive care for patients with chronic and complex conditions.

Yan Xia,1,* Panyu Zhou,1,* Xiaosong Cheng,1,* Yang Xie,1,* Chong Liang,2 Chao Li,1 Shuogui Xu1,2 1Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai, People's Republic of China; 2Department of Neurosurgery, The 81 Hospital of People's Liberation Army of China, Nanjing, People's Republic of China *These authors contributed equally to this work Abstract: The regeneration of functional tissue in osseous defects is a formidable challenge in orthopedic surgery. In the present study, a novel biomimetic composite scaffold, here called nano-hydroxyapatite (HA)/poly-ε-caprolactone (PCL) was fabricated using a selective laser sintering technique. The macrostructure, morphology, and mechanical strength of the scaffolds were characterized. Scanning electronic microscopy (SEM) showed that the nano-HA/PCL scaffolds exhibited predesigned, well-ordered macropores and interconnected micropores. The scaffolds have a range of porosity from 78.54% to 70.31%, and a corresponding compressive strength of 1.38 MPa to 3.17 MPa. Human bone marrow stromal cells were seeded onto the nano-HA/PCL or PCL scaffolds and cultured for 28 days in vitro. As indicated by the level of cell attachment and proliferation, the nano-HA/PCL showed excellent biocompatibility, comparable to that of PCL scaffolds. The hydrophilicity, mineralization, alkaline phosphatase activity, and Alizarin Red S staining indicated that the nano-HA/PCL scaffolds are more bioactive than the PCL scaffolds in vitro. Measurements of recombinant human bone morphogenetic protein-2 (rhBMP-2) release kinetics showed that after nano-HA was added, the material increased the rate of rhBMP-2 release. To investigate the in vivo biocompatibility and osteogenesis of the composite scaffolds, both nano-HA/PCL scaffolds and PCL scaffolds were implanted in rabbit femur defects for 3, 6, and 9 weeks. The wounds were studied radiographically and histologically. The in vivo results showed that both nano-HA/PCL composite scaffolds and PCL scaffolds exhibited good biocompatibility. However, the nano-HA/PCL scaffolds enhanced the efficiency of new bone formation more than PCL scaffolds and fulfilled all the basic requirements of bone tissue engineering scaffolds. Thus, they show large potential for use in orthopedic and reconstructive surgery. Keywords: osseous defects, orthopedic surgery, biomimetic composite scaffold, reconstructive surgery