Long-life mission reliability for outer planet atmospheric entry probes

The results of a literature analysis on the effects of prolonged exposure to deep space environment on the properties of outer planet atmospheric entry probe components are presented. Materials considered included elastomers and plastics, pyrotechnic devices, thermal control components, metal springs and electronic components. The rates of degradation of each component were determined and extrapolation techniques were used to predict the effects of exposure for up to eight years to deep space. Pyrotechnic devices were aged under accelerated conditions to an equivalent of eight years in space and functionally tested. Results of the literature analysis of the selected components and testing of the devices indicated that no severe degradation should be expected during an eight year space mission

Tropical belt width proportionately more sensitive to aerosols than greenhouse gases

The tropical belt has widened during the last several decades, and both internal variability and anthropogenic forcings have contributed. Although greenhouse gases and stratospheric ozone depletion have been implicated as primary anthropogenic drivers of tropical expansion, the possible role of other drivers remains uncertain. Here, we analyze the tropical belt width response to idealized perturbations in multiple models. Our results show that absorbing black carbon (BC) aerosol drives tropical expansion, and scattering sulfate aerosol drives contraction. BC, especially from Asia, is more efficient per unit radiative forcing than greenhouse gases in driving tropical expansion, particularly in the Northern Hemisphere. Tropical belt expansion (contraction) is associated with an increase (decrease) in extratropical static stability induced by absorbing (scattering) aerosol. Although a formal attribution is difficult, scaling the normalized expansion rates to the historical time period suggests that BC is the largest driver of the Northern Hemisphere tropical widening but with relatively large uncertainty

Processing The Interspecies Quorum-Sensing Signal Autoinducer-2 (AI-2) Characterization Of Phospho-(S)-4,5-Dihydroxy-2,3-Pentanedione Isomerization By LsrG Protein

The molecule (S)-4,5-dihydroxy-2,3-pentanedione (DPD) is produced by many different species of bacteria and is the precursor of the signal molecule autoinducer-2 (AI-2). AI-2 mediates interspecies communication and facilitates regulation of bacterial behaviors such as biofilm formation and virulence. A variety of bacterial species have the ability to sequester and process the AI-2 present in their environment, thereby interfering with the cell-cell communication of other bacteria. This process involves the AI-2-regulated lsr operon, comprised of the Lsr transport system that facilitates uptake of the signal, a kinase that phosphorylates the signal to phospho-DPD (P-DPD), and enzymes (like LsrG) that are responsible for processing the phosphorylated signal. Because P-DPD is the intracellular inducer of the lsr operon, enzymes involved in P-DPD processing impact the levels of Lsr expression. Here we show that LsrG catalyzes isomerization of P-DPD into 3,4,4-trihydroxy-2-pentanone-5-phosphate. We present the crystal structure of LsrG, identify potential catalytic residues, and determine which of these residues affects P-DPD processing in vivo and in vitro. We also show that an lsrG deletion mutant accumulates at least 10 times more P-DPD than wild type cells. Consistent with this result, we find that the lsrG mutant has increased expression of the lsr operon and an altered profile of AI-2 accumulation and removal. Understanding of the biochemical mechanisms employed by bacteria to quench signaling of other species can be of great utility in the development of therapies to control bacterial behavior

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

Space Station Engineering Design Issues

Space Station Freedom topics addressed include: general design issues; issues related to utilization and operations; issues related to systems requirements and design; and management issues relevant to design

Antibiofilm Efficacies of Flavonoid-Rich Sweet Orange Waste Extract against Dual-Species Biofilms

The current study evaluated the antibacterial properties of industrial sweet orange waste extracts (ISOWEs), which are a rich source of flavonoids. The ISOWEs exhibited antibacterial activity towards the dental cariogenic pathogens Streptococcus mutans and Lactobacillus casei with 13.0 ± 2.0 and 20.0 ± 2.0 mg/mL for MIC (minimum inhibitory concentration) and 37.7 ± 1.5 and 43.3 ± 2.1 mg/mL for MBC (minimum bactericidal concentration), respectively. When evaluated in a 7-day dual-species oral biofilm model, ISOWEs dose-dependently reduced the viable bacteria count, and demonstrated strong synergistic effects when combined with the anti-septic chlorhexidine (at 0.1 and 0.2%). Similarly, confocal microscopy confirmed the anti-cariogenic properties of ISOWEs, alone and in combination with chlorhexidine. The citrus flavonoids contributed differently to these effects, with the flavones (nobiletin, tangeretin and sinensetin) demonstrating significantly lower MICs and MBCs compared to the flavanones hesperidin and narirutin. In conclusion, our study demonstrated the potential of citrus waste as a currently underutilised source of flavonoids for antimicrobial applications, such as in dental health

Drivers of changes in stratospheric and tropospheric ozone between year 2000 and 2100

A stratosphere-resolving configuration of the Met Office’s Unified Model (UM) with the United Kingdom Chemistry and Aerosols (UKCA) scheme is used to investigate the atmospheric response to changes in a) greenhouse gases and climate, b) ozone-depleting substances (ODSs) and c) non-methane ozone precursor emissions. A suite of time-slice experiments show the separate, as well as pairwise, impacts of these perturbations between the years 2000 and 2100. Sensitivity to uncertainties in future greenhouse gases and aerosols is explored through the use of the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. The results highlight an important role for the stratosphere in determining the annual mean tropospheric ozone response, primarily through stratosphere-troposphere exchange of ozone (STE). Under both climate change and reductions in ODSs, increases in STE offset decreases in net chemical production and act to increase the tropospheric ozone burden. This opposesthe effects of projected decreases in ozone precursors through measures to improve air quality, which act to reduce the ozone burden. The global tropospheric lifetime of ozone (τO3) does not change significantly under climate change at RCP4.5, but it decreases at RCP8.5. This opposes the increases in τO3 simulated under reductions in both ODSs and ozone precursor emissions. The additivity of the changes in ozone is examined by comparing the sum of the responses in the single-forcing experiments to those from equivalent combined-forcing experiments. Whilst the ozone responses to most forcing combinations are found to be approximately additive, non-additive changes are found in both the stratosphere and troposphere when a large climate forcing (RCP8.5) is combined with the effects of ODSs

Cardiovascular disease risk score prediction models for women and its applicability to Asians

Purpose: Although elevated cardiovascular disease (CVD) risk factors are associated with a higher risk of developing heart conditions across all ethnic groups, variations exist between groups in the distribution and association of risk factors, and also risk levels. This study assessed the 10-year predicted risk in a multiethnic cohort of women and compared the differences in risk between Asian and Caucasian women. Methods: Information on demographics, medical conditions and treatment, smoking behavior, dietary behavior, and exercise patterns were collected. Physical measurements were also taken. The 10-year risk was calculated using the Framingham model, SCORE (Systematic COronary Risk Evaluation) risk chart for low risk and high risk regions, the general CVD, and simplified general CVD risk score models in 4,354 females aged 20–69 years with no heart disease, diabetes, or stroke at baseline from the third Australian Risk Factor Prevalence Study. Country of birth was used as a surrogate for ethnicity. Nonparametric statistics were used to compare risk levels between ethnic groups. Results: Asian women generally had lower risk of CVD when compared to Caucasian women. The 10-year predicted risk was, however, similar between Asian and Australian women, for some models. These findings were consistent with Australian CVD prevalence. Conclusion: In summary, ethnicity needs to be incorporated into CVD risk assessment. Australian standards used to quantify risk and treat women could be applied to Asians in the interim. The SCORE risk chart for low-risk regions and Framingham risk score model for incidence are recommended. The inclusion of other relevant risk variables such as obesity, poor diet/nutrition, and low levels of physical activity may improve risk estimation

Sustained intensification of the Aleutian Low induces weak tropical Pacific sea surface warming

It has been proposed that externally forced trends in the Aleutian Low can induce a basin-wide Pacific sea surface temperature (SST) response that projects onto the pattern of the Pacific Decadal Oscillation (PDO). To investigate this hypothesis, we apply local atmospheric nudging in an intermediate-complexity climate model to isolate the effects of an intensified winter Aleutian Low sustained over several decades. An intensification of the Aleutian Low produces a basin-wide SST response with a similar pattern to the model's internally generated PDO. The amplitude of the SST response in the North Pacific is comparable to the PDO, but in the tropics and southern subtropics the anomalies induced by the imposed Aleutian Low anomaly are a factor of 3 weaker than for the internally generated PDO. The tropical Pacific warming peaks in boreal spring, though anomalies persist year-round. A heat budget analysis shows the northern subtropical Pacific SST response is predominantly driven by anomalous surface turbulent heat fluxes in boreal winter, while in the equatorial Pacific the response is mainly due to meridional heat advection in boreal spring. The propagation of anomalies from the extratropics to the tropics can be explained by the seasonal footprinting mechanism, involving the wind–evaporation–SST feedback. The results show that low-frequency variability and trends in the Aleutian Low could contribute to basin-wide anomalous Pacific SST, but the magnitude of the effect in the tropical Pacific, even for the extreme Aleutian Low forcing applied here, is small. Therefore, external forcing of the Aleutian Low is unlikely to account for observed decadal SST trends in the tropical Pacific in the late 20th and early 21st centuries