Impacts of deforestation and burning, and the role of bracken fern, on the properties of surficial or buried soil A-horizons

Bracken fern (Pteridium spp.) is an aggressive plant that commonly invades disturbed sites. Its success as an invader is attributable, in part, to its ability to produce abundant growth, both below ground in the form of rhizomes and fine roots and above ground as fronds and stems. This biomass production has been shown to affect numerous soil properties. In describing soils of the „Pumice Lands‟ (Pumice Soils or Vitrands mainly) in New Zealand, Molloy and Christie (1998) attributed black A horizons „to bracken fern, which replaced much of the forest‟. Analyses of humus and phytoliths in the A horizons of soils developed especially on Kaharoa and Taupo tephras in central North Island (buried beneath 1886 Tarawera eruptives in the Rerewhakaaitu area) showed that type-A humic acids predominated and that fernland and grassland had replaced the pre-existing forests (Birrell et al., 1971; Sase et al., 1988; Hosono et al., 1991; Sase and Hosono, 1996). Pollen, phytolith and associated studies, together with tephrochronology, have shown that human-induced deforestation by burning began in New Zealand soon after Polynesian settlers arrived (e.g. McGlone, 1989; Clarkson et al., 1992; Kondo et al., 1994; McGlone et al., 1994; Newnham et al., 1998; McGlone and Wilmshurst, 1999; Watanabe and Sakagami, 1999; see also article on Polynesian settlement by Lowe, this volume). The repeated burning resulted in the formation of extensive fernlands (McGlone et al., 2005)

Flowfield measurements in a model scramjet combustion using laser-induced iodine fluorescence

Preliminary designs were completed for an iodine mixing chamber and the optical setup to be used with a modified wind tunnel in obtaining accurate, spatially resolved measurements of variables in the flowfield of a model nonreacting scramjet combustor. Schematics of the iodine-seeded wind tunnel and a sketch of the charcoal filter for removing the iodine are included along with a cutaway section of the laboratory

Investigating the Feasibility of Integrating Pavement Friction and Texture Depth Data in Modeling for INDOT PMS

Under INDOT’s current friction testing program, the friction is measured annually on interstates but only once every three years on non-interstate roadways. The state’s Pavement Management System, however, would require current data if friction were to be included in the PMS. During routine pavement condition monitoring for the PMS, texture data is collected annually. This study explored the feasibility of using this pavement texture data to estimate the friction during those years when friction is not measured directly. After multi0ple approaches and a wide variety of ways of examining the currently available data and texture measuring technologies, it was determined that it is not currently feasible to use the texture data as a surrogate for friction testing. This is likely because the lasers used at this time are not capable of capturing the small-scale pavement microtexture. This situation may change, however, with advances in laser or photo interpretation technologies and improved access to materials data throughout the INDOT pavement network

Mission and surface infrastructure concepts

Several types of manned Mars surface missions, including sorties, fixed-base, and hybrid missions, which can be envisioned as potentially desirable approaches to the exploration and utilization of Mars are identified and discussed. Some of the advantages and disadvantages of each type are discussed briefly. Also, some of the implications of the types of missions on the surface elements' design are discussed briefly. Typical sets of surface elements are identified for each type of mission, and weights are provided for each element and set

A Discussion on Armington Trade Substitution Elasticities

Applied partial and general equilibrium models used to examine trade policy are almost universally sensitive to trade elasticities. Indeed, the Armington elasticity, the degree of substitution between domestic and imported goods, is a key behavioral parameter that drives the quantitative, and sometimes the qualitative, results that policymakers use. While standard transparent approaches to econometric estimation of these elasticities have been offered for the last 30 years, the estimates are viewed as too small by many trade economists. A few robust findings emerge from the econometric literature: (1) more disaggregate analyses find higher elasticities, (2) long-run estimates are higher than short-run estimates, and (3) time series analyses generally find lower elasticities relative to cross-sectional studies. We offer simulation results to illustrate the sensitivity of general equilibrium models to Armington elasticites. We conclude with remarks on the current challenges that remain in determining these important parameters.International Relations/Trade,

A Discussion on Armington Trade Substitution Elasticities

Applied partial and general equilibrium models used to examine trade policy are almost universally sensitive to trade elasticities. Indeed, the Armington elasticity, the degree of substitution between domestic and imported goods, is a key behavioral parameter that drives the quantitative, and sometimes the qualitative, results that policymakers use. While standard transparent approaches to econometric estimation of these elasticities have been offered for the last 30 years, the estimates are viewed as too small by many trade economists. A few robust findings emerge from the econometric literature: (1) more disaggregate analyses find higher elasticities, (2) long-run estimates are higher than short-run estimates, and (3) time series analyses generally find lower elasticities relative to cross-sectional studies. We offer simulation results to illustrate the sensitivity of general equilibrium models to Armington elasticites. We conclude with remarks on the current challenges that remain in determining these important parameters.Computable general equilibrium; International Trade; Armington; elasticity