New Measurement of Exclusive Decays of the chi_c0 and chi_c2 to Two-Meson Final States

Using a sample of 2.59 times 10^7 psi(2S) decays collected by the CLEO--c detector, we present results of a study of chi_{c0} and chi_{c2} decays into two-meson final states. We present the world's most precise measurements of the chi_{cJ,(J=0,2)} -> pi^+pi^-, pi^0 pi^0, K^+K^-, K^0_S K^0_S, eta eta and eta^{prime} eta^{prime} branching fractions, and a search for chi_c decays into eta eta^{prime}. These results shed light on the mechanism of charmonium decays into pseudoscalar mesons.Comment: 7 pages, available through http://www.lns.cornell.edu/public/CLNS/, submitted to Phys. Rev.

Observation of chi_cJ radiative decays to light vector mesons

Using a total of 2.74 x 10^7 decays of the psi(2S) collected with the CLEO-c detector, we present a study of chi_cJ -> gamma V, where V = rho^0, omega, phi. The transitions chi_c1 -> gamma rho^0 and chi_c1 -> gamma omega are observed with B(chi_c1 -> gamma rho^0) = (2.43 +- 0.19 +- 0.22) x 10^-4 and B(chi_c1 -> gamma omega) = (8.3 +- 1.5 +- 1.2) x 10^-5. In the chi_c1 -> gamma rho^0 transition, the final state meson is dominantly longitudinally polarized. Upper limits on the branching fractions of other chi_cJ states to light vector mesons are presented.Comment: 10 pages, available through http://www.lns.cornell.edu/public/CLNS

Search for psi(2S) -> gamma eta_c(2S) via fully reconstructed eta_c(2S) decays

We report a search for the decay psi(2S) -> gamma eta_c(2S) in a sample of 25.9 million psi(2S) events collected with the CLEO-c detector. No signals are observed in any of the 11 exclusive eta_c(2S) decay modes studied, or in their sum. Product branching fraction upper limits are determined as a function of Gamma[eta_c(2S)] for the 11 individual modes.Comment: 21 pages, 7 figures, updated to published version (PRD 81, 052002 (2010)

Modeling the impacts of wood pellet demand on forest dynamics in southeastern United States

The export of wood pellets from the southeastern United States (USA) has grown significantly in recent years, following rising demand from Europe. Increased wood pellet demand could lead to spatially variable changes in timberland management and area in the USA. This study presents an assessment of the impacts of increasing wood pellet demand (an additional 11.6 Mt by 2030) on land-use dynamics, taking into account developments in other wood product markets as well as expected changes in other land uses. An economic model for the forest sector of the southeastern USA (SRTS) was linked to a land-use change model (PLUC) to identify potential locations of land-use change following scenarios of demand for pellets and other wood products. Projections show that in the absence of additional demand for wood pellets, natural timberland area is projected to decline by 450–15 000 km2 by 2030, mainly through urbanization and pine plantation establishment. Under the high wood pellet demand scenario, more (2000–7500 km2) natural timberland area is retained and more (8000–20 000 km2) pine plantation is established. Shifts from natural timberland to pine plantation occur predominantly in the Atlantic coastal region. Future work will assess the impact of projected transitions in natural timberland and pine plantations on biodiversity and carbon storage. This modeling framework can be applied for multiple scenarios and land-use projections to identify locations of timberland area changes for the whole southeastern USA, thereby informing the debate about potential impacts of wood pellet demand on land-use dynamics and environmental services

Wood pellets, what else? : Greenhouse gas parity times of European electricity from wood pellets produced in the south-eastern United States using different softwood feedstocks

Several EU countries import wood pellets from the south-eastern United States. The imported wood pellets are (co-)fired in power plants with the aim of reducing overall greenhouse gas (GHG) emissions from electricity and meeting EU renewable energy targets. To assess whether GHG emissions are reduced and on what timescale, we construct the GHG balance of wood-pellet electricity. This GHG balance consists of supply chain and combustion GHG emissions, carbon sequestration during biomass growth and avoided GHG emissions through replacing fossil electricity. We investigate wood pellets from four softwood feedstock types: small roundwood, commercial thinnings, harvest residues and mill residues. Per feedstock, the GHG balance of wood-pellet electricity is compared against those of alternative scenarios. Alternative scenarios are combinations of alternative fates of the feedstock materials, such as in-forest decomposition, or the production of paper or wood panels like oriented strand board (OSB). Alternative scenario composition depends on feedstock type and local demand for this feedstock. Results indicate that the GHG balance of wood-pellet electricity equals that of alternative scenarios within 0–21 years (the GHG parity time), after which wood-pellet electricity has sustained climate benefits. Parity times increase by a maximum of 12 years when varying key variables (emissions associated with paper and panels, soil carbon increase via feedstock decomposition, wood-pellet electricity supply chain emissions) within maximum plausible ranges. Using commercial thinnings, harvest residues or mill residues as feedstock leads to the shortest GHG parity times (0–6 years) and fastest GHG benefits from wood-pellet electricity. We find shorter GHG parity times than previous studies, for we use a novel approach that differentiates feedstocks and considers alternative scenarios based on (combinations of) alternative feedstock fates, rather than on alternative land uses. This novel approach is relevant for bioenergy derived from low-value feedstocks

Managing dependencies in forest offset projects: toward a more complete evaluation of reversal risk

Carbon offsets, Climate policy, Forestry, Natural disturbance, Risk,