Peatlands and the carbon cycle: from local processes to global implications - a synthesis

Peatlands cover only 3% of the Earth's land surface but boreal and subarctic peatlands store about 15-30% of the world's soil carbon ( C) as peat. Despite their potential for large positive feedbacks to the climate system through sequestration and emission of greenhouse gases, peatlands are not explicitly included in global climate models and therefore in predictions of future climate change. In April 2007 a symposium was held in Wageningen, the Netherlands, to advance our understanding of peatland C cycling. This paper synthesizes the main findings of the symposium, focusing on (i) small-scale processes, (ii) C fluxes at the landscape scale, and (iii) peatlands in the context of climate change. The main drivers controlling most are related to some aspects of hydrology. Despite high spatial and annual variability in Net Ecosystem Exchange ( NEE), the differences in cumulative annual NEE are more a function of broad scale geographic location and physical setting than internal factors, suggesting the existence of strong feedbacks. In contrast, trace gas emissions seem mainly controlled by local factors. Key uncertainties remain concerning the existence of perturbation thresholds, the relative strengths of the CO2 and CH4 feedback, the links among peatland surface climate, hydrology, ecosystem structure and function, and trace gas biogeochemistry as well as the similarity of process rates across peatland types and climatic zones. Progress on these research areas can only be realized by stronger co-operation between disciplines that address different spatial and temporal scales

Marry & Burn by Rachel Rose

Review of Rachel Rose\u27s Marry & Burn

Search for Supersymmetry Signatures at the LHC

Supersymmetry (SUSY) is one of the most interesting and comprehensively studied models for new physics beyond the Standard Model. If SUSY exists in nature the Large Hadron Collider will provide excellent opportunities to search for SUSY. SUSY discovery strategies of the ATLAS and CMS experiments are presented with a focus on early data. SUSY mass measurement techniques and determination of SUSY model parameters are also demonstrated.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July 2009, eConf C09072

Particle conservation in numerical models of the tokamak plasma edge

The test particle Monte-Carlo models for neutral particles are often used in the tokamak edge modelling codes. The drawback of this approach is that the self-consistent solution suffers from random error introduced by the statistical method. A particular case where the onset of nonphysical solutions can be clearly identified is violation of the global particle balance due to non-converged residuals. There are techniques which can reduce the residuals - such as internal iterations in the code B2-EIRENE - but they may pose severe restrictions on the time-step and slow down the computations. Numerical diagnostics described in the paper can be used to unambiguously identify when the too large error in the global particle balance is due to finite-volume residuals, and their reduction is absolutely necessary. Algorithms which reduce the error while allowing large time-step are also discussed.Comment: Link to journal publication: http://aip.scitation.org/doi/full/10.1063/1.498085

Special Libraries, January 1946

Volume 37, Issue 1https://scholarworks.sjsu.edu/sla_sl_1946/1000/thumbnail.jp

Special Libraries, October 1959

Volume 50, Issue 8https://scholarworks.sjsu.edu/sla_sl_1959/1007/thumbnail.jp

Special Libraries, December 1939

Volume 30, Issue 10https://scholarworks.sjsu.edu/sla_sl_1939/1009/thumbnail.jp