THE IMPORTANCE OF THE MARKET AREA DETERMINATION FOR ESTIMATING AGGREGATE BENEFITS OF PUBLIC GOODS: TESTING DIFFERENCES IN RESIDENT AND NONRESIDENT WILLINGNESS TO PAY

A combined telephone contact-mail booklet-telephone interview of California and New England households regarding their willingness to pay for fire management in California and Oregon's old-growth forests was performed to test hypotheses regarding the spatial extent of the public goods market. Using a multiple-bounded contingent valuation question, the study found that New England households' annual willingness to pay for the California and Oregon programs was statistically different from zero. This analysis points out that households receive benefits from fire protection of old-growth forests in states other than their own. In this case study, limiting the survey sample to state residents where the National Forest is located would reflect about 20% of the national benefits. However, using resident values as a proxy for nonresidents would overstate the national benefits by 75%, since the values per household are significantly different. This finding suggests more emphasis in future surveys on selecting an institutionally and economically relevant sample frame rather than an expedient one.Consumer/Household Economics,

Spatial Limits of the TCM revisited: Island Effects

The purpose of this paper is to address a problem that may arise with the assumption of a continuous spatial market in the TCM model. We find that this assumption can be challenged by geographical limitations that an area of study might have. Particularly for islands (or isolated island-like areas) that have a valuable non-market resource or good, the spatial market characteristic of the TCM model might be limited or truncated. The geographical truncation limits the observed maximum travel cost of the demand curve falsely implying a lower WTP than otherwise. The study uses a dichotomous choice CVM to confirm that the resulting demand schedules from the TCM underestimates WTP for day trips to the Caribbean National Forest in Puerto Rico. This results in a considerably smaller TCM WTP for the value of recreation sites at $17 to$29 versus $109 per day trip from the dichotomous choice CVM.Marketing,

TESTING FOR DIFFERENTIAL EFFECTS OF FOREST FIRES ON HIKING AND MOUNTAIN BIKING DEMAND AND BENEFITS

Surveys of visitors to National Forests in Colorado were conducted to determine whether different fire ages and presence of crown fires have different effects on hiking and mountain biking recreation visits and benefits. Actual and intended behavior data were combined using a count-data travel cost model. The intended behavior trip questions asked about changes in number of trips due to the presence of a high-intensity crown fire, prescribed fire, and a 20-year-old high-intensity fire at the area respondents were visiting. Using the estimated recreation demand function, years since a non-crown fire had statistically significant positive effect on the trip demand of hikers. In contrast, presence of crown fires had no statistically significant effect on the quantity of hiker trips, but had a significant and negative effect on mountain biking trips. Crown fires also had a large effect on the value per trip, with crown fires increasing the value per hiking trip but lowering the value per mountain biking trip.Resource /Energy Economics and Policy,

Microstructure Evolution During Powder Compaction

The process of powder compaction consists of the synthesis of loose powders into a solid material. The applications of compaction of granular systems extend to pharmaceuticals, detergents, food, ceramic and metallurgical processes. It is indispensable to have a thorough understanding of the behavior of confined granular systems during compaction because the performance of the final desired product is related to the microstructural features that develop during the compaction process. To have a more realistic description of the compaction, it is also important to include the packing process of granular systems. However, there are different particle packing algorithms that account for the particle filling process. The Discrete Element Method (DEM) had been used to obtain a dynamic solution to this problem but requires high computational power. As an alternative to the computationally expensive DEM approach, a static based algorithm has recently been developed for the modelling and simulation of the particle packing process. The algorithm allows for the modelling of the packing process by placing spheres inside different shapes and sizes of containers. In this study, we present a new version of the nanoHUB Powder Compaction tool. It currently simulates the microstructure evolution of monodisperse, compressible granular systems up to high relative densities. The tool also models the plastic and elastic deformation of single particles described by different contact mechanics models. The new features use a general particle packing algorithm and thus allow the user to choose a particle size distribution in a specified range for the mean, standard deviation and number of particles to fill the die. The information is passed to the solver that in turn simulates the compaction in Purdue’s high-performance computer cluster

Calcium/calmodulin kinase1 and its relation to thermotolerance and HSP90 in Sporothrix schenckii: an RNAi and yeast two-hybrid study

<p>Abstract</p> <p>Background</p> <p><it>Sporothrix schenckii </it>is a pathogenic dimorphic fungus of worldwide distribution. It grows in the saprophytic form with hyaline, regularly septated hyphae and pyriform conidia at 25°C and as the yeast or parasitic form at 35°C. Previously, we characterized a calcium/calmodulin kinase in this fungus. Inhibitors of this kinase were observed to inhibit the yeast cell cycle in <it>S. schenckii</it>.</p> <p>Results</p> <p>The presence of RNA interference (RNAi) mechanism in this fungus was confirmed by the identification of a Dicer-1 homologue in <it>S. schenckii </it>DNA. RNAi technology was used to corroborate the role of calcium/calmodulin kinase I in <it>S. schenckii </it>dimorphism. Yeast cells were transformed with the pSilent-Dual2G (pSD2G) plasmid w/wo inserts of the coding region of the calcium/calmodulin kinase I (<it>sscmk1</it>) gene. Transformants were selected at 35°C using resistance to geneticin. Following transfer to liquid medium at 35°C, RNAi transformants developed as abnormal mycelium clumps and not as yeast cells as would be expected. The level of <it>sscmk1 </it>gene expression in RNAi transformants at 35°C was less than that of cells transformed with the empty pSD2G at this same temperature. Yeast two-hybrid analysis of proteins that interact with SSCMK1 identified a homologue of heat shock protein 90 (HSP90) as interacting with this kinase. Growth of the fungus similar to that of the RNAi transformants was observed in medium with geldanamycin (GdA, 10 μM), an inhibitor of HSP90.</p> <p>Conclusions</p> <p>Using the RNAi technology we silenced the expression of <it>sscmk1 </it>gene in this fungus. RNAi transformants were unable to grow as yeast cells at 35°C showing decreased tolerance to this temperature. The interaction of SSCMK1 with HSP90, observed using the yeast two-hybrid assay suggests that this kinase is involved in thermotolerance through its interaction with HSP90. SSCMK1 interacted with the C terminal domain of HSP90 where effector proteins and co-chaperones interact. These results confirmed SSCMK1 as an important enzyme involved in the dimorphism of <it>S. schenckii</it>, necessary for the development of the yeast phase of this fungus. Also this study constitutes the first report of the transformation of <it>S. schenckii </it>and the use of RNAi to study gene function in this fungus.</p

THE IMPORTANCE OF THE MARKET AREA DETERMINATION FOR ESTIMATING AGGREGATE BENEFITS OF PUBLIC GOODS: TESTING DIFFERENCES IN RESIDENT AND NONRESIDENT WILLINGNESS TO PAY

A combined telephone contact-mail booklet-telephone interview of California and New England households regarding their willingness to pay for fire management in California and Oregon's old-growth forests was performed to test hypotheses regarding the spatial extent of the public goods market. Using a multiple-bounded contingent valuation question, the study found that New England households' annual willingness to pay for the California and Oregon programs was statistically different from zero. This analysis points out that households receive benefits from fire protection of old-growth forests in states other than their own. In this case study, limiting the survey sample to state residents where the National Forest is located would reflect about 20% of the national benefits. However, using resident values as a proxy for nonresidents would overstate the national benefits by 75%, since the values per household are significantly different. This finding suggests more emphasis in future surveys on selecting an institutionally and economically relevant sample frame rather than an expedient one

Testing Welfare Measurement Gains of Combining Stated and Revealed Preferences Methods Using Count Data Models

This research updates the joint estimation of revealed and stated preference data of Cameron (1992) to allow for joint estimation of the Travel Cost Method (TCM) portion using count data models. Further these count data models reflect correction for truncation and endogenous stratification associated with commonly used on-site recreation sampling. Our updated modeling framework also allows for testing of consistency of behavior between revealed and stated preference data rather than imposing it. Our empirical example is river recreation visitors to the Caribbean National Forest in Puerto Rico. For this data set we find consistency between revealed preference and stated preference data. We also find little gain in estimation efficiency in our data. This may be due to our contingent valuation question eliciting willingness to pay for existing site conditions, a benefit measure conceptually very similar to what is estimated with TCM. However, our updated joint estimation may make a significant improvement in estimation efficiency when the contingent valuation scenarios involve major changes in site quality not reflected in the TCM data