Effects of land markets and land management on ecosystem function: A framework for modelling exurban land-change

This paper presents the conceptual design and application of a new land-change modelling framework that represents geographical, sociological, economic, and ecological aspects of a land system. The framework provides an overarching design that can be extended into specific model implementations to evaluate how policy, land-management preferences, and land-market dynamics affect (and are affected by) land-use and land-cover change patterns and subsequent carbon storage and flux. To demonstrate the framework, we implement a simple integration of a new agent-based model of exurban residential development and land-management decisions with the ecosystem process model BIOME-BGC. Using a stylized scenario, we evaluate the influence of different exurban residential-land-management strategies on carbon storage at the parcel level over a 48-year period from 1958 to 2005, simulating stocks of carbon in soil, litter, vegetation, and net primary productivity. Results show 1) residential parcels with management practices that only provided additions in the form of fertilizer and irrigation to turfgrass stored slightly more carbon than parcels that did not include management practices, 2) conducting no land-management strategy stored more carbon than implementing a strategy that included removals in the form of removing coarse woody debris from dense tree cover and litter from turfgrass, and 3) the removal practices modelled had a larger impact on total parcel carbon storage than our modelled additions. The degree of variation within the evaluated land-management practices was approximately 42,104 kg C storage on a 1.62 ha plot after 48 years, demonstrating the substantial effect that residential land-management practices can have on carbon storag

Direct Numerical Simulation of Turbulent Heat Transfer Modulation in Micro-Dispersed Channel Flow

The object of this paper is to study the influence of dispersed micrometer size particles on turbulent heat transfer mechanisms in wall-bounded flows. The strategic target of the current research is to set up a methodology to size and design new-concept heat transfer fluids with properties given by those of the base fluid modulated by the presence of dynamically-interacting, suitably-chosen, discrete micro- and nano- particles. We run Direct Numerical Simulation (DNS) for hydrodynamically fully-developed, thermally-developing turbulent channel flow at shear Reynolds number Re=150 and Prandtl number Pr=3, and we tracked two large swarms of particles, characterized by different inertia and thermal inertia. Preliminary results on velocity and temperature statistics for both phases show that, with respect to single-phase flow, heat transfer fluxes at the walls increase by roughly 2% when the flow is laden with the smaller particles, which exhibit a rather persistent stability against non-homogeneous distribution and near-wall concentration. An opposite trend (slight heat transfer flux decrease) is observed when the larger particles are dispersed into the flow. These results are consistent with previous experimental findings and are discussed in the frame of the current research activities in the field. Future developments are also outlined.Comment: Pages: 305-32

The International Dosimetry Exchange for BNCT: A Basis for Pooling and Collectively Analyzing Clinical Results

An international collaboration was organized by the Massachusetts Institute of Technology (MIT) to undertake a dosimetry exchange for the eventual purpose of combining results from various clinical centers that employ different methods for measuring and prescribing absorbed dose in the mixed radiation fields used for neutron capture therapy. Treatment plans calculated at NCT centers in the Czech Republic, Finland, The Netherlands and Sweden were normalized to corresponding measurements performed by the MIT dosimetry group in each beam. More than half of the normalizations for individual absorbed dose components (photon, fast neutron, thermal neutron and boron) determined by comparing MIT measurements to the dose specified in treatment plans from the different centers were statistically significant and ranged from 8 to 400%. Each facility had at least one dose component that would require normalization for the specified doses to be accurately compared. These normalizations establish a technical basis to begin collectively analyzing treatment plans between the European and US centers. Simple but pertinent treatment parameters such as the maximum dose to brain can now be properly compared, once the clinical data is available. This could help to more precisely and quickly determine various dose-response relationships as for example those related to adverse events. Future efforts to determine dose normalizations at other centers performing human studies as well as more sophisticated analyses using combined data from several centers should be guided by clearly defined clinical objectives with active participation from clinical BNCT experts.JRC.F.3-High Flux and Future Reactor