Most flowering plant species contain at least two copies of the DEFECTIVE EMBRYO AND MERISTEMS (DEM) gene with the encoded DEM proteins lacking homology to proteins of known biochemical function. In ...tomato (Sl; Solanum lycopersicum), stable mutations in the SlDEM1 locus result in shoot and root meristem defects with the dem1 mutant failing to progress past the cotyledon stage of seedling development. Generation of a Somatic Mutagenesis of DEM1 (SMD) transformant line in tomato allowed for the characterization of SlDEM1 gene function past the seedling stage of vegetative development with SMD plants displaying a range of leaf development abnormalities. Further, the sectored or stable in planta expression of specific regions of the SlDEM1 coding sequence also resulted in the generation of tomato transformants that displayed a range of vegetative development defects, which when considered together with the dem1 mutant seedling and SMD transformant line phenotypic data, allowed for the assignment of SlDEM1 gene function to early embryo development, adaxial epidermis cell development, lateral leaf blade expansion, and mesophyll cell proliferation and differentiation.
This prospective placebo-controlled trial was designed to determine whether intravenous immune globulin (IVIG) improves left ventricular ejection fraction (LVEF) in adults with recent onset of ...idiopathic dilated cardiomyopathy or myocarditis.
Sixty-two patients (37 men, 25 women; mean age +/-SD 43.0+/-12.3 years) with recent onset (</=6 months of symptoms) of dilated cardiomyopathy and LVEF </=0.40 were randomized to 2 g/kg IVIG or placebo. All underwent an endomyocardial biopsy before randomization, which revealed cellular inflammation in 16%. The primary outcome was change in LVEF at 6 and 12 months after randomiz. Overall, LVEF improved from 0.25+/-0.08 to 0.41+/-0.17 at 6 months (P<0.001) and 0.42+/-0.14 (P<0.001 versus baseline) at 12 months. The increase was virtually identical in patients receiving IVIG and those given placebo (6 months: IVIG 0.14+/-0.12, placebo 0.14+/-0.14; 12 months: IVIG 0.16+/-0.12, placebo 0.15+/-0.16). Overall, 31 (56%) of 55 patients at 1 year had an increase in LVEF >/=0.10 from study entry, and 20 (36%) of 56 normalized their ejection fraction (>/=0.50). The transplant-free survival rate was 92% at 1 year and 88% at 2 years.
These results suggest that for patients with recent-onset dilated cardiomyopathy, IVIG does not augment the improvement in LVEF. However, in this overall cohort, LVEF improved significantly during follow-up, and the short-term prognosis remains favorable.
Up to now our understanding of the 11 year ozone solar cycle signal (SCS) in the upper stratosphere has been largely based on the Stratospheric Aerosol and Gas Experiment (SAGE) II (v6.2) data ...record, which indicated a large positive signal which could not be reproduced by models, calling into question our understanding of the chemistry of the upper stratosphere. Here we present an analysis of new v7.0 SAGE II data which shows a smaller upper stratosphere ozone SCS, due to a more realistic ozone‐temperature anticorrelation. New simulations from a state‐of‐art 3‐D chemical transport model show a small SCS in the upper stratosphere, which is in agreement with SAGE v7.0 data and the shorter Halogen Occultation Experiment and Microwave Limb Sounder records. However, despite these improvements in the SAGE II data, there are still large uncertainties in current observational and meteorological reanalysis data sets, so accurate quantification of the influence of solar flux variability on the climate system remains an open scientific question.
Key Points
Updated SAGE v7.0 data shows improved O3‐T anti‐correlation in the upper stratosphere
Reduced solar signal in the upper stratosphere in SAGE v7.0 data is consistent with model and HALOE data
Large uncertainties in observational (and reanalysis) data, hinders establishing the true nature of solar signal in the stratospheric ozone
Up to now our understanding of the 11year ozone solar cycle signal (SCS) in the upper stratosphere has been largely based on the Stratospheric Aerosol and Gas Experiment (SAGE) II (v6.2) data record, ...which indicated a large positive signal which could not be reproduced by models, calling into question our understanding of the chemistry of the upper stratosphere. Here we present an analysis of new v7.0 SAGE II data which shows a smaller upper stratosphere ozone SCS, due to a more realistic ozone-temperature anticorrelation. New simulations from a state-of-art 3-D chemical transport model show a small SCS in the upper stratosphere, which is in agreement with SAGE v7.0 data and the shorter Halogen Occultation Experiment and Microwave Limb Sounder records. However, despite these improvements in the SAGE II data, there are still large uncertainties in current observational and meteorological reanalysis data sets, so accurate quantification of the influence of solar flux variability on the climate system remains an open scientific question.
Aerosols and their effect on the radiative properties of clouds are one of the largest sources of uncertainty in calculations of the Earth's energy budget. Here the sensitivity of aerosol‐cloud ...albedo effect forcing to 31 aerosol parameters is quantified. Sensitivities are compared over three periods; 1850–2008, 1978–2008, and 1998–2008. Despite declining global anthropogenic SO2 emissions during 1978–2008, a cancelation of regional positive and negative forcings leads to a near‐zero global mean cloud albedo effect forcing. In contrast to existing negative estimates, our results suggest that the aerosol‐cloud albedo effect was likely positive (0.006 to 0.028Wm−2) in the recent decade, making it harder to explain the temperature hiatus as a forced response. Proportional contributions to forcing variance from aerosol processes and natural and anthropogenic emissions are found to be period dependent. To better constrain forcing estimates, the processes that dominate uncertainty on the timescale of interest must be better understood.
Key Points
Forcing sensitivity to aerosol parameters is strongly period dependentUnderstanding near‐future climate is limited if a single period is consideredIn recent decades, parametric uncertainty is smaller than model diversity
Tropospheric aerosol radiative forcing has persisted for many years as one of the major causes of uncertainty in global climate model simulations. To sample the range of plausible aerosol and ...atmospheric states and perform robust statistical analyses of the radiative forcing, it is important to account for the combined effects of many sources of model uncertainty, which is rarely done due to the high computational cost. This paper describes the designs of two ensembles of the Met Office Hadley Centre Global Environment Model‐U.K. Chemistry and Aerosol global climate model and provides the first analyses of the uncertainties in aerosol radiative forcing and their causes. The first ensemble was designed to comprehensively sample uncertainty in the aerosol state, while the other samples additional uncertainties in the physical model related to clouds, humidity, and radiation, thereby allowing an analysis of uncertainty in the aerosol effective radiative forcing. Each ensemble consists of around 200 simulations of the preindustrial and present‐day atmospheres. The uncertainty in aerosol radiative forcing in our ensembles is comparable to the range of estimates from multimodel intercomparison projects. The mean aerosol effective radiative forcing is −1.45 W/m2 (credible interval of −2.07 to −0.81 W/m2), which encompasses but is more negative than the −1.17 W/m2 in the 2013 Atmospheric Chemistry and Climate Model Intercomparison Project and −0.90 W/m2 in the Intergovernmental Panel on Climate Change Fifth Assessment Report. The ensembles can be used to reduce aerosol radiative forcing uncertainty by challenging them with multiple measurements as well as to isolate potential causes of multimodel differences.
Plain Language Summary
Atmospheric aerosol particles such as dust, pollutants, and smoke interfere with light from the Sun and modify the properties of clouds and thereby affect Earth's climate. However, the effect that aerosols have on climate is one of the major causes of uncertainty in global climate model simulations. We performed a large number of climate model simulations (called an ensemble), with many parts of the model slightly varied, in order to understand the complex behavior of the model and to explore the causes of uncertainty in model outputs. This paper describes the designs of two climate model ensembles and provides the first analyses of the causes of model uncertainty. The first ensemble was designed to comprehensively understand the behavior of aerosols in the atmosphere, while the other includes more general uncertainties in atmospheric processes that can affect aerosols. Each ensemble consists of around 200 simulations. The ranges of the aerosol climate effect in our ensembles are comparable to the ranges of previous estimates from studies that analyzed multiple climate models. These ensembles can be used to reduce uncertainty in how aerosols affect climate by comparing with satellite and ground‐based measurements.
Key Points
Two ensembles of atmospheric simulations were performed perturbing aerosol and physical parameters under different model setups
Thousands of Gaussian process emulators sampling parameter spaces enabled statistical analyses of model's parametric uncertainty.
Fully explored parametric uncertainty of aerosol radiative forcing in a model was found to be comparable to that in multimodel studies
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