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This study uses contingent valuation to determine consumer’s willingness-to-pay (WTP) for reducing hydrilla in two alternative spring-fed river systems in Northwest Florida - the Wacissa River (an open access park) and the Wakulla Springs (a gated park). Two dissimilar payment vehicles -gate and power bill fees- are used to assess the economic value of reducing the density of this aquatic weed. A total sample of 317 recreational users was used to estimate their WTP for a 50% reduction in the density of hydrilla. Our results show a favorable response from consumers to pay for a hydrilla reduction program. Specifically, at Wakulla Springs, the average WTP is $1.63 for monthly power bill surcharge and $3.76 for per trip gate fee. Conversely, at the Wacissa River the average WTP is $1.49 power bill surcharge. This study also analyzes the determinants affecting consumer’s WTP. Our results show that respondents who are from the local surrounding area are more likely to participate and pay a program to reduce hydrilla. In addition, the amenities available in the park also influence consumer’s WTP. Policy implications stemming from these results are also discussed.

Choice of payment vehicle (PV) is important to contingent-valuation practitioners. They are often left using scenarios that may elicit bias responses; for example hypothetical gate fees in open access areas. Utility bills may avoid bias, but introduce a scaling problem. A survey of north-Florida spring-based recreation calibrates these two dissimilar PVs.

Poster was presented at the Purdue Libraries One Book Higher Poster Session. Focus is on the activities and experimentation within the virtual world Second Life by the Purdue Libraries. Key projects were the virtual presentation of Amelia Earhart photographs and a simulation in a restaurant setting for hospitality & tourism management research.

The mechanism by which antigens are processed and presented to T cells exerts a powerful influence on all immune responses, including those directed against pathogens. Knowledge of the peptides produced by antigen presenting cells for presentation to T cells is important in understanding why individuals have different abilities to combat infection and may prove critical in the design of new vaccines. The aim of this project was to attempt to use a novel metabolic labelling technique to enable biochemical identification of potential T cell epitopes in bacterial antigens. The technique is based upon labelling antigens with the stable isotope carbon-13, and subsequent identification of antigen-derived peptides using mass spectrometric isotopic composition analysis. The ultimate goal of the work was to pulse antigen presenting cells with labelled bacteria and identify MHC class II-associated bacteriaderived peptides with the objective of identifying potential vaccine candidates. Towards this goal, outer membrane proteins were prepared and analysed by polyacrylamide gel electrophoresis and immunoblotted with serum from healthy individuals. The results showed that the serum antibodies bound to a number of outer membrane proteins, confirming that they contained B cell epitopes. As a first step to demonstrate that the outer membrane proteins also contained T cell epitopes, it was shown that whole bacteria and bacterial antigens can be successfully labelled with carbon-13 such that all derived peptide fragments may be distinguished by isotopic analysis. However, due to the complexity of the peptide mixture generated by a tryptic digest of the outer membrane proteins, it was critical to combine isotope analysis with excellent chromatographic resolution in order to identify carbon-13 labelled peptides. To address this problem, a new high sensitivity 2D nanoflow liquid chromatography system was developed and its capabilities compared with conventional ID reverse phase chromatographic techniques. Two dimensional separation prior to mass spectral analysis substantially improved the separation of complex biological mixtures leading to an improvement in the identification of carbon-13 labelled peptides in such mixtures. Two dimensional chromatography and carbon-13 labelling was then applied to investigate the processing of tetanus toxin C fragment (TTCF) by lysosomes isolated from EBV transformed B lymphoblastoid cell lines. Whilst large TTCF fragments were demonstrably generated during processing, small (