Statistical diagnostic and correction of a chemistry-transport model for the prediction of total column ozone

International audienceIn this paper, we introduce a statistical method for examining and adjusting chemical-transport models. We illustrate the findings with total column ozone predictions, based on the University of Illinois at Urbana-Champaign 2-D (UIUC 2-D) chemical-transport model of the global atmosphere. We propose a general diagnostic procedure for the model outputs in total ozone over the latitudes ranging from 60° South to 60° North to see if the model captures some typical patterns in the data. The method proceeds in two steps to avoid possible collinearity issues. First, we regress the measurements given by a cohesive data set from the SBUV(/2) satellite system on the model outputs with an autoregressive noise component. Second, we regress the residuals of this first regression on the solar flux, the annual cycle, the Antarctic or Arctic Oscillation, and the Quasi Biennial Oscillation. If the coefficients from this second regression are statistically significant, then they mean that the model did not simulate properly the pattern associated with these factors. Systematic anomalies of the model are identified using data from 1979 to 1995, and statistically corrected afterwards. The 1996?2003 validation sample confirms that the combined approach yields better predictions than the direct UIUC 2-D outputs

Levels of α7 integrin and laminin-α2 are increased following prednisone treatment in the mdx mouse and GRMD dog models of Duchenne muscular dystrophy

SUMMARY Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disease for which there is no cure and limited treatment options. Prednisone is currently the first line treatment option for DMD and studies have demonstrated that it improves muscle strength. Although prednisone has been used for the treatment of DMD for decades, the mechanism of action of this drug remains unclear. Recent studies have shown that the α7β1 integrin is a major modifier of disease progression in mouse models of DMD and is therefore a target for drug-based therapies. In this study we examined whether prednisone increased α7β1 integrin levels in mdx mouse and GRMD dog models and myogenic cells from humans with DMD. Our results show that prednisone promotes an increase in α7 integrin protein in cultured myogenic cells and in the muscle of mdx and GRMD animal models of DMD. The prednisone-mediated increase in α7 integrin was associated with increased laminin-α2 in prednisone-treated dystrophin-deficient muscle. Together, our results suggest that prednisone acts in part through increased merosin in the muscle basal lamina and through sarcolemmal stabilization of α7β1 integrin in dystrophin-deficient muscle. These results indicate that therapies that target an increase in muscle α7β1 integrin, its signaling pathways and/or laminin could be therapeutic in DMD

Halocarbon ozone depletion and global warming potentials

Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H atom, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen atom in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global warming)

U.S. GLOBAL CHANGE RESEARCH PROGRAM CLIMATE SCIENCE SPECIAL REPORT (CSSR)

Fifth-Order Draft Table of Contents Front Matter About This Report........................................................................................ 1 Guide to the Report......................................................................................4 Executive Summary ................................................................................... 12 Chapters 1. Our Globally Changing Climate .......................................................... 38 2. Physical Drivers of Climate Change ................................................... 98 3. Detection and Attribution of Climate Change .................................... 160 4. Climate Models, Scenarios, and Projections .................................... 186 5. Large-Scale Circulation and Climate Variability ................................ 228 6. Temperature Changes in the United States ...................................... 267 7. Precipitation Change in the United States ......................................... 301 8. Droughts, Floods, and Hydrology ......................................................... 336 9. Extreme Storms ....................................................................................... 375 10. Changes in Land Cover and Terrestrial Biogeochemistry ............ 405 11. Arctic Changes and their Effects on Alaska and the Rest of the United States..... 443 12. Sea Level Rise ....................................................................................... 493 13. Ocean Acidification and Other Ocean Changes .............................. 540 14. Perspectives on Climate Change Mitigation .................................... 584 15. Potential Surprises: Compound Extremes and Tipping Elements .......... 608 Appendices A. Observational Datasets Used in Climate Studies ............................. 636 B. Weighting Strategy for the Fourth National Climate Assessment ................ 642 C. Detection and Attribution Methodologies Overview ............................ 652 D. Acronyms and Units ................................................................................. 664 E. Glossary ...................................................................................................... 66

U.S. GLOBAL CHANGE RESEARCH PROGRAM CLIMATE SCIENCE SPECIAL REPORT (CSSR)

Fifth-Order Draft Table of Contents Front Matter About This Report........................................................................................ 1 Guide to the Report......................................................................................4 Executive Summary ................................................................................... 12 Chapters 1. Our Globally Changing Climate .......................................................... 38 2. Physical Drivers of Climate Change ................................................... 98 3. Detection and Attribution of Climate Change .................................... 160 4. Climate Models, Scenarios, and Projections .................................... 186 5. Large-Scale Circulation and Climate Variability ................................ 228 6. Temperature Changes in the United States ...................................... 267 7. Precipitation Change in the United States ......................................... 301 8. Droughts, Floods, and Hydrology ......................................................... 336 9. Extreme Storms ....................................................................................... 375 10. Changes in Land Cover and Terrestrial Biogeochemistry ............ 405 11. Arctic Changes and their Effects on Alaska and the Rest of the United States..... 443 12. Sea Level Rise ....................................................................................... 493 13. Ocean Acidification and Other Ocean Changes .............................. 540 14. Perspectives on Climate Change Mitigation .................................... 584 15. Potential Surprises: Compound Extremes and Tipping Elements .......... 608 Appendices A. Observational Datasets Used in Climate Studies ............................. 636 B. Weighting Strategy for the Fourth National Climate Assessment ................ 642 C. Detection and Attribution Methodologies Overview ............................ 652 D. Acronyms and Units ................................................................................. 664 E. Glossary ...................................................................................................... 66