On the management of interconnected wildlife populations

Economic interdependency of wildlife or fish stocks is usually attributed to ecological interdependency, such as predator - prey and competitive relationships, or to density dependent migration of species between different areas. This paper provides another channel for economic interdependency of wildlife where density independent migration and market price interaction affect the management strategies among different landowners. Management is studied under three market conditions for selling hunting licences: price taking behaviour, monopoly market and duopoly market. Harvesting of the Scandinavian moose is used as an example. The paper provides several results on how economic interdependency works through the migration pattern. When a duopoly market is introduced, hunting license price interaction among the landowners plays an additional role in determining the optimal harvesting strategy.

Investigation of functionalized carbon nanotubes as a delivery system for enhanced gene expression with implications in developing DNA vaccines for hepatitis C virus

Hepatitis C virus (HCV) causes a significant health problem worldwide due to the lack of effective vaccines. It has been recognized that a rapid, vigorous, and broadly targeted cell-mediated immune response (Th1-like) is often associated with the clearance of HCV infections. DNA vaccines represent a promising means for HCV vaccination because they tend to induce a Th1-biased cell-mediated response in the host cell. Currently, the delivery of DNA vaccine for HCV in large animals as well as in humans is not as effective as in small animals. Nano delivery systems would be a promising approach to overcome this problem. Carbon nanotubes (CNTs) have been extensively studied for delivering drugs, proteins, peptides, and nucleic acids including plasmid DNA to cells and organs with varying degrees of success, but few of them have been applied to DNA vaccine for HCV. This thesis presents a study of using functionalized CNTs (f-CNTs) to improve the efficacy of plasmid DNA vaccine delivery for HCV. First, CNTs were functionalized via 1,3-dipolar cycloaddition reaction with the appropriate amino acids and aldehydes. NMR and TEM results suggested that the CNTs were successfully functionalized and became soluble in water. Then plasmid DNAs which encode green fluorescence protein reporter gene, luciferase reporter gene, and HCV core protein, respectively, were delivered into human hepatoma cells via calcium phosphate precipitation method, f-CNT delivery system, and a combination of f-CNT and calcium phosphate method, respectively. The result showed that f-CNTs, in combination with the calcium phosphate method, significantly enhanced the gene expression in human hepatoma cells. Consequently, this study concludes that the f-CNT can significantly enhance gene expression in liver cells conferred by a plasmid DNA when combined with calcium phosphate precipitation method. Even though the mechanisms of this enhancement await further investigation, the results of this thesis may have important implications in developing DNA vaccines for infectious diseases in general and for hepatitis C in particular

Estimating the non-market benefit value of deep-sea ecosystem restoration: Evidence from a contingent valuation study of the Dohrn Canyon in the Bay of Naples

Embargo until 21.08.2022.It is increasingly recognized that restoration actions in marine environments are required in order to deal with continued habitat degradation and to support conservation strategies. Restoration success is judged on the ecological outcomes but with limited resources the magnitude of the societal benefits achieved is an important consideration for policy makers. This study demonstrates how the potential non-market benefit value of a deep-sea restoration project might be assessed. The contingent valuation method is employed to elicit the Italian population's willingness to pay for the restoration of the Dohrn deep-sea canyon in the Bay of Naples. Sample selection models that control for the impact of protest zero bidders on benefit value estimation are compared to more traditional modelling approaches. The results indicate a positive willingness to pay for the restoration of the canyon ecosystem and the importance of accounting for protest zero bidders in contingent valuation studies, especially when the environmental good is unfamiliar to respondents. The paper argues that the inclusion of non-market benefit values is particularly important in assessing the potential for marine ecosystem restoration if a true reflection of the value to society of restoring such habitats are to be correctly captured.acceptedVersio

Analytically Pricing Credit Default Swaps under a Regime-Switching Model

In this paper, we consider the valuation of a CDS (credit default swap) contract when the reference asset is assumed to follow a regime-switching model with the volatility allowed to jump among different states. Our motivation originates from empirical evidence demonstrating the existence of regime-switching in real markets. The default probability is analytically derived first, based on which a closed-form formula for the CDS price is obtained so that it can be easily implemented for practical purposes. Finally, numerical experiments are carried out to show quantitatively some properties of the CDS price under the regime-switching model

Biological Invasion and Coexistence in Intraguild Predation

Invasion of an exotic species initiated by its local introduction is considered subject to intraguild predation (IGP). Mathematically, the system dynamics is described by three nonlinear diffusion-reaction equations in two spatial dimensions. The key factors that determine successful invasion are investigated by means of extensive numerical simulations. The results reveal high asymmetry. An exotic species can invade successfully if it acted as the top predator and engaged in IGP, and the IGP interactions of the postinvasion web will be kept. While the exotic species were introduced as the intraguild prey (IGprey), they invade and spread through patchy invasion which corresponds to the invasion at the edge of extinction. Increase of the IGprey's dispersal rate and decrease of the IGpredator's may make the IGprey invade. But the interactions of the postinvasion web will change from IGP to competition, which is absolutely different from the first case. Finally, the common existence of IGP was explored once again from the perspective of biological invasion

The Service Quality Evaluation of Mobile Communication from Quality Improvement Perspective ----a case study on China telecom in Wuchang District Wuhan City

Based on SERVAUAL model, this paper brings in the entropy method to rank quality improvement (QI) priority for service attributes, and a service quality evaluation(SQE) model integrating competitive analyses has been structured to evaluate the mobile communication service quality (SQ) for Wuhan Branch of China Telecom(WBCT). The research shows that the QI priority of 22 service attributes has changed as adopts entropy method comparing with gap-based SERVQUAL. The service attributes that finally should be improved have changed from Q20(Various business charges reasonable) and Q22(Record customer complaints and improve) to Q21(provide customers all kinds of value-added services) and Q11(Staff serves with high efficiency)