This thesis is a collection of essays on the problem of overfishing in multifirm fisheries with a common property fish stock. We focus on the case of marine industrial fisheries, where the costs of preventing free riding tend to preclude cooperative harvesting. We study the overfishing problem by analysing harvesting incentives that stem from variations in (i) technological (cost, production and biological growth) functions, (ii) institutional factors (access schemes, regulatory agencies' instruments and their monitoring and enforcement powers, harvesting competition), and (iii) objective functions (private firms' planning horizons, welfare functions). Chapter 2 discusses conditions under which a fishing collapse can occur and examines the commonly held argument that fishing collapse is a public bad. Chapter 3 studies Chilean fishing regulations over the last five decades. The regulator's persistent inability to enforce annual quotas is analysed. Distributive disputes and triggered lobbying powers are examined. The late 1980s controversies over a new Chilean fishing law are analysed in-depth from this perspective. Chapter 4 explains the main motivations and key assumptions leading us to the oligopoly harvesting models of chapters 5 (static setting) and 6 (dynamic setting). These models focus on a deterministic single fish species and a single sector harvesting fishery composed of profit maximizing and price taking private firms that compete with each other by following non-cooperative harvesting strategies. These models examine the overfishing rankings that result from comparing Cournot-Nash and Stackelberg equilibria. First best and second best welfare benchmarks are considered. The Cournot-Nash setting is intended to illustrate a large number oligopolistic fishery, while the Stackelberg equilibrium is meant to be a first approximation to analyse the implications of harvesting fisheries subject to industrial concentration. Empirical evidence suggesting the presence of industrial concentration in a series of important marine industrial fisheries is described in chapters 3 and 4.

Among the core concerns with the extraordinary proliferation of land deals in Africa - often referred to as "land grabs" - is that the signing of contracts between host states and foreign companies and/or other states for large swaths of territory and associated agribusinesses could represent an erosion of the host state's sovereignty powers. This concern reveals a double characterisation of the state, as weak in its sovereignty and, yet, as very able to negotiate and implement deals. Host states have been shown to be able to exercise sovereignty in those deals, what type of sovereignty - and whose -, however, remains in dispute. This thesis seeks to address this issue through a case study that focuses on the question how sovereignties are shaping and being shaped by land deals in Mozambique's Limpopo Valley. It specifically investigates the rice and sugar projects in areas of the Chokwe and Xai-Xai regadios. It considers land deals as a set of processes for international-domestic negotiation of goals and funding, followed by processes in the areas of decision-making, policy-making, and project implementation. Based on critical reappraisals of the concept of sovereignty, the thesis understands sovereignty as a set of powers that a state effectively has, beyond mere legal sovereignty, rather than an a priori attribute that a state does or does not possess, in zero-sum terms. As such it is an outcome of relational, inter-subjective processes and, thus, dynamic and historically contingent. Consequently, rather than absolute power over its territory and population, sovereignty is considered in terms of degrees of two types of political power practices, "command" power and "infrastructural" power, according to multiple and not always congruent state functions. To this, the thesis brings a notion of socially constructed state such that it is never neutral because a part of society and, thus socially embedded and produced. This allows me to move past the assumption of 'common good' and the moralist discussions of 'elite capture' and corruption. Based on this theoretical and analytical framework, the thesis posits irrigated agriculture and the state schemes hosting foreign projects as "sites" where actors' interests and powers are shaped relationally: the state (in different capacities), other states and their development agencies, foreign private sector actors and multiple domestic groups. The processes are studied at two levels. The first concerns how state "command" power is used to harness and/or defend against different international developments, negotiating international narratives and domestic needs, resulting in agricultural and water regulations, with ODA dependence for budgets. A subset of regulatory activity is the revisions to by-laws of management irrigation-scheme companies, as new representatives of central power locally. At the second level, the research focuses on interaction with Western equity and Chinese cooperation projects, two of the main types of investors, which come with different foreign management and funding models. Further, processes are embedded in historical trajectories of elite groups' moving away from agriculture since the 1980s, yet holding on to land entitlements, and of producers' displacement. This analytical framework allows research to effectively go beyond the notion of the state as either weak or able, considering it as polymorphous and acting in specific dimensions that no longer seem contradictory. Further, it illuminates the mutually constitutive nature of (sub)national and international dimensions of sovereignty, which tend to be exiled from each other in mainstream approaches to the notion, as well as the inextricability of political and economic powers in the 'sovereignty frontier' of post-conditionality states.

Detailed analysis of the physical, chemical, pollen and diatom stratigraphy of sediment cores from Bull Run Lake, Oregon reveals that the lake has been subject to repeated episodes of disruption by volcanic ash fall, fire and other disturbance over the past 4300 years. With the exception of fire, these disruptions have not resulted in long term changes in the watershed or in the characteristics of Bull Run Lake. A major fire in the watershed about 750 years ago altered the vegetation. Since that time the forest has been returning to its former condition.

In this thesis, heat and moisture transfer between supply and exhaust air streams are investigated for a run-around system in which the coupling material is a desiccant coated solid that is transported between two exchangers. The finite difference method is used to solve the governing partial differential equations of the cross-flow heat exchangers in the supply and exhaust ducts. The outlet air properties are calculated for several inlet air operating conditions and desiccant properties. The accuracy of the heat transfer model is verified by comparing the simulations with well-known theoretical solutions for a single cross flow heat exchanger and a liquid coupled run-around system. The difference between the analytical predictions and the numerical model for sensible effectiveness for each exchanger and the run-around system were found to be less than 1% over a range of operating conditions. The model is also verified by modifying the boundary conditions to represent a counter flow energy wheel and comparing the calculated sensible, latent, and total effectiveness values with correlations in the literature. <p>Using the verified model for energy exchangers and the run-around energy recovery system, the sensible, latent and overall effectiveness are investigated in each exchanger and the run-around system during simultaneous heat and moisture transfer. The overall effectiveness of the run-around energy recovery system is dependent on the air flow rate, the solid desiccant flow rate, the desiccant properties, specific surface area, the size of each exchanger, and the inlet air operating conditions. The run-around system can achieve a high overall effectiveness when the flow rates and exchangers properties are properly chosen. Comparisons between the solid desiccant and salt solution run-around system effectiveness (Fan, 2005 and Fan et al, 2006) shows they are in good agreement. In a sensitivity study, the thickness of desiccant on the fibre is investigated in the solid run-around system. It was found that good performance is obtained with very thin desiccant coatings (1 or 2 micron). During the practical use of this system, a desiccant coated fibre could be inserted into very porous balls or cages that protect the desiccant coated fiber from mechanical wear. The performance sensitivity for this kind of run-around system is demonstrated.

A child’s level of physical activity is an important component of that child’s health. Our understanding of physical activity patterns in children is limited in rural settings, and virtually absent for climates with snow cover. Opportunities for physical activity intervention need to be identified. PURPOSE: Investigation of the relationships between pedometer-measured physical activity, body composition and aerobic performance in rural children in the winter and examination of within-day variation in stepping behavior using interval pedometry. METHODS: Aerobic performance (20 m shuttle run) with “talk test” validation and body composition (BMI, BF) were measured during mid-winter during the school year in 8 to 10 year old children. Pedometer step counts were recorded at 6 intervals throughout the day for 7 days. RESULTS: Fifty-six subjects (22 males and 34 females, mean age 9.09 (0.49), had the following measurements; BMI 17.9 (3.3), BF% 24.3 (9.5) (tricep/calf), 10,465 (±2506) steps/day, VO2 45.12 ml/kg/min (±2.87), shuttle run stage 3.0 (±1.34). Weekday steps/day (11,422 ±2573) were greater than weekend (8,112, ±3499) steps/day for both boys and girls (p<0.01). Town children recorded 1800 more steps/day than out of town children (p<0.01). All measures of body composition were found to be significantly related to aerobic power (p<0.01). Weekday steps were related to aerobic performance. The fittest (upper 1/3) children were leaner and had more afternoon school steps, and higher afternoon school step rates. CONCLUSION: Daily step counts were 2000-4000 steps lower than other studies and may be an impact of winter in Manitoba or the rural setting. This was consistent with overall low aerobic performance and higher adiposity of the children. Interval pedometry was capable of identifying differences in activity patterns between most and least fit children in rural Manitoba providing for targeted intervention strategies. / October 2006

In this thesis, heat and moisture transfer between supply and exhaust air streams are investigated for a run-around system in which the coupling material is a desiccant coated solid that is transported between two exchangers. The finite difference method is used to solve the governing partial differential equations of the cross-flow heat exchangers in the supply and exhaust ducts. The outlet air properties are calculated for several inlet air operating conditions and desiccant properties. The accuracy of the heat transfer model is verified by comparing the simulations with well-known theoretical solutions for a single cross flow heat exchanger and a liquid coupled run-around system. The difference between the analytical predictions and the numerical model for sensible effectiveness for each exchanger and the run-around system were found to be less than 1% over a range of operating conditions. The model is also verified by modifying the boundary conditions to represent a counter flow energy wheel and comparing the calculated sensible, latent, and total effectiveness values with correlations in the literature. <p>Using the verified model for energy exchangers and the run-around energy recovery system, the sensible, latent and overall effectiveness are investigated in each exchanger and the run-around system during simultaneous heat and moisture transfer. The overall effectiveness of the run-around energy recovery system is dependent on the air flow rate, the solid desiccant flow rate, the desiccant properties, specific surface area, the size of each exchanger, and the inlet air operating conditions. The run-around system can achieve a high overall effectiveness when the flow rates and exchangers properties are properly chosen. Comparisons between the solid desiccant and salt solution run-around system effectiveness (Fan, 2005 and Fan et al, 2006) shows they are in good agreement. In a sensitivity study, the thickness of desiccant on the fibre is investigated in the solid run-around system. It was found that good performance is obtained with very thin desiccant coatings (1 or 2 micron). During the practical use of this system, a desiccant coated fibre could be inserted into very porous balls or cages that protect the desiccant coated fiber from mechanical wear. The performance sensitivity for this kind of run-around system is demonstrated.

<p>The central puzzles in financial economics commonly include</p><p>violations of the expectations hypotheses, predictability of excess returns, and the levels and volatilities of nominal bond yields, in addition to well-known equity premium and the risk-free rate puzzles.</p><p>Equally surprising is the recent evidence on large moves in asset prices, and the over-pricing of the out-of-the-money index put options relative to standard models. In this work, I argue that the long-run risks type model can successfully explain these features of financial markets. I present robust empirical evidence which supports the main economic channels in the model. Finally, I develop econometric methods to estimate and test the model, and find that it delivers plausible preference and model parameters and provides a good fit to the asset-price and macroeconomic data.</p><p>In the first chapter, which is co-authored with Ravi Bansal, we present a long-run risks based equilibrium model that can quantitatively explain the violations of expectations hypotheses and predictability of returns in bond and currency markets. The key ingredients of the model include a low-frequency predictable component in consumption, time-varying consumption volatility and investor's preferences for early resolution of uncertainty. In this model, varying consumption volatility in the presence of the predictable consumption component leads to appropriate variation in bond yields and the risk premia to provide an explanation for the puzzling violations of the expectations hypothesis. Using domestic and foreign consumption and asset markets data we provide direct empirical support for the economic channels highlighted in the paper.</p><p>In the second chapter, co-authored with Ravi Bansal, we develop a general equilibrium model in which income and dividends are smooth, but asset prices are subject to large moves (jumps). A prominent feature of the model is that the optimal decision of investors to learn the unobserved state triggers large asset-price jumps. We show that the learning choice is critically determined by preference parameters and the conditional volatility of income process. An important prediction of the model is that income volatility predicts future jumps, while the variation in the level of income does not. We find that indeed in the data large moves in returns are predicted by consumption volatility, but not by the changes in the consumption level. In numerical calibrations, we show that the model can quantitatively capture these novel features of the data.</p><p>In the third chapter, I present a long-run risks type model where consumption shocks are Gaussian, and the agent learns about unobserved expected growth from the cross-section of signals. The uncertainty about expected growth (confidence measure), as in the data, is time-varying and subject to jump-like risks. I show that the confidence jump risk channel can quantitatively account for the option price puzzles and large moves in asset prices, without hard-wiring jumps into consumption. Based on two estimation approaches, the model provides a good fit to the option price, confidence measure, returns and consumption data, at the plausible preference and model parameter values.</p> / Dissertation

¡@¡@The research on collection or reflection of solitary waves mainly focus on numerical model and theoretical analytics, there are few study on experiment. due to the process on reaction of solitary waves are very short in times, and the waveform is also hardly to measure quantifiable. ¡@¡@The method present in this paper that we setup a high speed camera at a fixed position, and a grid-point board is located in the water tank and out of the tank after pictured, then we capture the process on reflection of solitary wave at a wall by high speed camera, so that the waveform and the grid surface coincide. finally, we analyze the waveform within the grid by using image techniques. ¡@¡@The results of this paper that present several important parameters in several relative wave height, such as maximal run-up, residual time, phase shift..et.al. the other hand, this paper compare the result of experiment with available evidences likes numerical model and theoretical analytics that found to be in quantitative agreement. ¡@¡@In addition, this paper also present the result of experiment that could compare with the new phenomenon "residual falling jet¡¨, it`s published by Chambarel.et.al (2009) numerical model.

Shewhart X bar control charts with estimated control limits are widely used in practice. When the sample size is not fixed,we propose seven statistics to estimate the standard deviation sigma . These estimators are applied to estimate the control limits of Shewhart X bar control chart. The estimated results through simulated computation are given and discussed. Finally, we investigate the performance of the Shewhart X bar control charts based on the seven estimators of sigma via its simulated average run length (ARL).

The rollers of run out table in Hot Strip Mill are operated with variable high rotational speed under a severe environment of high temperature and much cooling water around. And the table takes long space about 128 meters of length with over 330 rollers. The rollers of this area often break down, and it takes long to make urgent repair. So it costs about ten million NT dollars per year for mill shut-down. Although some improvements have been made before, the troubles still happens frequently. Then the temporary countermeasures of shortening the maintenance cycle and increasing the grease supply have been applied to prevent the break-down frequency from aggravation . But it wastes the cost and does not meet the environmental policy. This study analyzes many damage phenomena. Then it assumes that the 75% of roller running break-down is bearing damage resulting from bad lubrication condition and abnormal axial load. The cooling water which penetrates into bearing housing will result in grease emulsification and its consistency diluting. This certainly causes the bad lubrication condition and bearing rusting. In the meantime, if the floating function of roller bearing is inactive, the bearings will be operated under abnormal high axial load and without appropriate lubrication. Then the bearing will be damaged rapidly and must be repaired quickly. In order to improve bad lubrication and bearing rusting, this study modifies sealing arrangement and grease feeding circuit for bearing housing with the special functions of water obstruction, drainage and resistance to prevent water penetration. In addition, the overflow of grease will be collected to meet the environmental needs. Meanwhile, to look for better water resistance and mechanical stability for greasing, the study also discusses the relationship between consistency variation and thickening soap base after grease emulsification. During a three-month running of the new design , the water contents are stably under 1.5% which has greatly advanced. And the quantity of grease supply is under 10% of existing one. In order to improve the inactive floating function of roller bearings, this study not only analyzes the derivation of problems but also modifies the dimensional tolerance and adds cylindricity of geometric tolerance for the bore of bearing housing. This will ensure complete loose fit and shape accuracy to prevent the interference fit between the bore and bearing caused by manufacturing inaccuracy or other mistakes