1. |
- Abozid, Hazim, et al.
(author)
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Prevalence of chronic cough, its risk factors and population attributable risk in the Burden of Obstructive Lung Disease (BOLD) study : a multinational cross-sectional study
- 2024
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In: eClinicalMedicine. - : Elsevier. - 2589-5370. ; 68
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Journal article (peer-reviewed)abstract
- Background Chronic cough is a common respiratory symptom with an impact on daily activities and quality of life. Global prevalence data are scarce and derive mainly from European and Asian countries and studies with outcomes other than chronic cough. In this study, we aimed to estimate the prevalence of chronic cough across a large number of study sites as well as to identify its main risk factors using a standardised protocol and definition. Methods We analysed cross-sectional data from 33,983 adults (>= 40 years), recruited between Jan 2, 2003 and Dec 26, 2016, in 41 sites (34 countries) from the Burden of Obstructive Lung Disease (BOLD) study. We estimated the prevalence of chronic cough for each site accounting for sampling design. To identify risk factors, we conducted multivariable logistic regression analysis within each site and then pooled estimates using random -effects metaanalysis. We also calculated the population attributable risk (PAR) associated with each of the identifed risk factors. Findings The prevalence of chronic cough varied from 3% in India (rural Pune) to 24% in the United States of America (Lexington,KY). Chronic cough was more common among females, both current and passive smokers, those working in a dusty job, those with a history of tuberculosis, those who were obese, those with a low level of education and those with hypertension or airflow limitation. The most influential risk factors were current smoking and working in a dusty job. Interpretation Our findings suggested that the prevalence of chronic cough varies widely across sites in different world regions. Cigarette smoking and exposure to dust in the workplace are its major risk factors.
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2. |
- Amaral, Andre F. S., et al.
(author)
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Chronic airflow obstruction and ambient particulate air pollution
- 2021
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In: Thorax. - : BMJ Publishing Group Ltd. - 0040-6376 .- 1468-3296. ; 76:12, s. 1236-1241
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Journal article (peer-reviewed)abstract
- Smoking is the most well-established cause of chronic airflow obstruction (CAO) but particulate air pollution and poverty have also been implicated. We regressed sex-specific prevalence of CAO from 41 Burden of Obstructive Lung Disease study sites against smoking prevalence from the same study, the gross national income per capita and the local annual mean level of ambient particulate matter (PM2.5) using negative binomial regression. The prevalence of CAO was not independently associated with PM2.5 but was strongly associated with smoking and was also associated with poverty. Strengthening tobacco control and improved understanding of the link between CAO and poverty should be prioritised.
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4. |
- Beaty, D.W, et al.
(author)
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The potential science and engineering value of samples delivered to Earth by Mars sample return : International MSR Objectives and Samples Team (iMOST)
- 2019
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In: Meteoritics and Planetary Science. - : John Wiley & Sons. - 1086-9379 .- 1945-5100. ; 54:S1, s. 3-152
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Journal article (peer-reviewed)abstract
- Executive Summary: Return of samples from the surface of Mars has been a goal of the international Mars science community for many years. Affirmation by NASA and ESA of the importance of Mars exploration led the agencies to establish the international MSR Objectives and Samples Team (iMOST). The purpose of the team is to re-evaluate and update the sample-related science and engineering objectives of a Mars Sample Return (MSR) campaign. The iMOST team has also undertaken to define the measurements and the types of samples that can best address the objectives. Seven objectives have been defined for MSR, traceable through two decades of previously published international priorities. The first two objectives are further divided into sub-objectives. Within the main part of the report, the importance to science and/or engineering of each objective is described, critical measurements that would address the objectives are specified, and the kinds of samples that would be most likely to carry key information are identified. These seven objectives provide a framework for demonstrating how the first set of returned Martian samples would impact future Martian science and exploration. They also have implications for how analogous investigations might be conducted for samples returned by future missions from other solar system bodies, especially those that may harbor biologically relevant or sensitive material, such as Ocean Worlds (Europa, Enceladus, Titan) and others. Summary of Objectives and Sub-Objectives for MSR Identified by iMOST: Objective 1 Interpret the primary geologic processes and history that formed the Martian geologic record, with an emphasis on the role of water. Intent To investigate the geologic environment(s) represented at the Mars 2020 landing site, provide definitive geologic context for collected samples, and detail any characteristics that might relate to past biologic processesThis objective is divided into five sub-objectives that would apply at different landing sites. 1.1 Characterize the essential stratigraphic, sedimentologic, and facies variations of a sequence of Martian sedimentary rocks. Intent To understand the preserved Martian sedimentary record. Samples A suite of sedimentary rocks that span the range of variation. Importance Basic inputs into the history of water, climate change, and the possibility of life 1.2 Understand an ancient Martian hydrothermal system through study of its mineralization products and morphological expression. Intent To evaluate at least one potentially life-bearing “habitable” environment Samples A suite of rocks formed and/or altered by hydrothermal fluids. Importance Identification of a potentially habitable geochemical environment with high preservation potential. 1.3 Understand the rocks and minerals representative of a deep subsurface groundwater environment. Intent To evaluate definitively the role of water in the subsurface. Samples Suites of rocks/veins representing water/rock interaction in the subsurface. Importance May constitute the longest-lived habitable environments and a key to the hydrologic cycle. 1.4 Understand water/rock/atmosphere interactions at the Martian surface and how they have changed with time. Intent To constrain time-variable factors necessary to preserve records of microbial life. Samples Regolith, paleosols, and evaporites. Importance Subaerial near-surface processes could support and preserve microbial life. 1.5 Determine the petrogenesis of Martian igneous rocks in time and space. Intent To provide definitive characterization of igneous rocks on Mars. Samples Diverse suites of ancient igneous rocks. Importance Thermochemical record of the planet and nature of the interior. Objective 2 Assess and interpret the potential biological history of Mars, including assaying returned samples for the evidence of life. Intent To investigate the nature and extent of Martian habitability, the conditions and processes that supported or challenged life, how different environments might have influenced the preservation of biosignatures and created nonbiological “mimics,” and to look for biosignatures of past or present life.This objective has three sub-objectives: 2.1 Assess and characterize carbon, including possible organic and pre-biotic chemistry. Samples All samples collected as part of Objective 1. Importance Any biologic molecular scaffolding on Mars would likely be carbon-based. 2.2 Assay for the presence of biosignatures of past life at sites that hosted habitable environments and could have preserved any biosignatures. Samples All samples collected as part of Objective 1. Importance Provides the means of discovering ancient life. 2.3 Assess the possibility that any life forms detected are alive, or were recently alive. Samples All samples collected as part of Objective 1. Importance Planetary protection, and arguably the most important scientific discovery possible. Objective 3 Quantitatively determine the evolutionary timeline of Mars. Intent To provide a radioisotope-based time scale for major events, including magmatic, tectonic, fluvial, and impact events, and the formation of major sedimentary deposits and geomorphological features. Samples Ancient igneous rocks that bound critical stratigraphic intervals or correlate with crater-dated surfaces. Importance Quantification of Martian geologic history. Objective 4 Constrain the inventory of Martian volatiles as a function of geologic time and determine the ways in which these volatiles have interacted with Mars as a geologic system. Intent To recognize and quantify the major roles that volatiles (in the atmosphere and in the hydrosphere) play in Martian geologic and possibly biologic evolution. Samples Current atmospheric gas, ancient atmospheric gas trapped in older rocks, and minerals that equilibrated with the ancient atmosphere. Importance Key to understanding climate and environmental evolution. Objective 5 Reconstruct the processes that have affected the origin and modification of the interior, including the crust, mantle, core and the evolution of the Martian dynamo. Intent To quantify processes that have shaped the planet's crust and underlying structure, including planetary differentiation, core segregation and state of the magnetic dynamo, and cratering. Samples Igneous, potentially magnetized rocks (both igneous and sedimentary) and impact-generated samples. Importance Elucidate fundamental processes for comparative planetology. Objective 6 Understand and quantify the potential Martian environmental hazards to future human exploration and the terrestrial biosphere. Intent To define and mitigate an array of health risks related to the Martian environment associated with the potential future human exploration of Mars. Samples Fine-grained dust and regolith samples. Importance Key input to planetary protection planning and astronaut health. Objective 7 Evaluate the type and distribution of in-situ resources to support potential future Mars exploration. Intent To quantify the potential for obtaining Martian resources, including use of Martian materials as a source of water for human consumption, fuel production, building fabrication, and agriculture. Samples Regolith. Importance Production of simulants that will facilitate long-term human presence on Mars. Summary of iMOST Findings: Several specific findings were identified during the iMOST study. While they are not explicit recommendations, we suggest that they should serve as guidelines for future decision making regarding planning of potential future MSR missions. The samples to be collected by the Mars 2020 (M-2020) rover will be of sufficient size and quality to address and solve a wide variety of scientific questions. Samples, by definition, are a statistical representation of a larger entity. Our ability to interpret the source geologic units and processes by studying sample sub sets is highly dependent on the quality of the sample context. In the case of the M-2020 samples, the context is expected to be excellent, and at multiple scales. (A) Regional and planetary context will be established by the on-going work of the multi-agency fleet of Mars orbiters. (B) Local context will be established at field area- to outcrop- to hand sample- to hand lens scale using the instruments carried by M-2020. A significant fraction of the value of the MSR sample collection would come from its organization into sample suites, which are small groupings of samples designed to represent key aspects of geologic or geochemical variation. If the Mars 2020 rover acquires a scientifically well-chosen set of samples, with sufficient geological diversity, and if those samples were returned to Earth, then major progress can be expected on all seven of the objectives proposed in this study, regardless of the final choice of landing site. The specifics of which parts of Objective 1 could be achieved would be different at each of the final three candidate landing sites, but some combination of critically important progress could be made at any of them. An aspect of the search for evidence of life is that we do not know in advance how evidence for Martian life would be preserved in the geologic record. In order for the returned samples to be most useful for both understanding geologic processes (Objective 1) and the search for life (Objective 2), the sample collection should contain BOTH typical and unusual samples from the rock units explored. This consideration should be incorporated into sample selection and the design of the suites. The retrieval missions of a MSR campaign should (1) minimize stray magnetic fields to which the samples would be exposed and carry a magnetic witness plate to record exposure, (2) collect and return atmospheric gas sample(s), and (3) collect additional dust and/or regolith sample mass if possible.
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5. |
- Burney, Peter, et al.
(author)
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Prevalence and Population-Attributable Risk for Chronic Airflow Obstruction in a Large Multinational Study
- 2021
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In: American Journal of Respiratory and Critical Care Medicine. - 1073-449X .- 1535-4970. ; 203:11, s. 1353-1365
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Journal article (peer-reviewed)abstract
- Rationale: The Global Burden of Disease program identified smoking and ambient and household air pollution as the main drivers of death and disability from chronic obstructive pulmonary disease (COPD).Objectives: To estimate the attributable risk of chronic airflow obstruction (CAO), a quantifiable characteristic of COPD, due to several risk factors.Methods: The Burden of Obstructive Lung Disease study is a cross-sectional study of adults, aged ≥40, in a globally distributed sample of 41 urban and rural sites. Based on data from 28,459 participants, we estimated the prevalence of CAO, defined as a postbronchodilator FEV1-to-FVC ratio less than the lower limit of normal, and the relative risks associated with different risk factors. Local relative risks were estimated using a Bayesian hierarchical model borrowing information from across sites. From these relative risks and the prevalence of risk factors, we estimated local population attributable risks.Measurements and Main Results: The mean prevalence of CAO was 11.2% in men and 8.6% in women. The mean population attributable risk for smoking was 5.1% in men and 2.2% in women. The next most influential risk factors were poor education levels, working in a dusty job for ≥10 years, low body mass index, and a history of tuberculosis. The risk of CAO attributable to the different risk factors varied across sites.Conclusions: Although smoking remains the most important risk factor for CAO, in some areas, poor education, low body mass index, and passive smoking are of greater importance. Dusty occupations and tuberculosis are important risk factors at some sites.
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6. |
- Černok, Ana, et al.
(author)
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Lunar samples record an impact 4.2 billion years ago that may have formed the Serenitatis Basin
- 2021
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In: Communications Earth & Environment. - : Springer Science and Business Media LLC. - 2662-4435. ; 2:1
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Journal article (peer-reviewed)abstract
- Impact cratering on the Moon and the derived size-frequency distribution functions of lunar impact craters are used to determine the ages of unsampled planetary surfaces across the Solar System. Radiometric dating of lunar samples provides an absolute age baseline, however, crater-chronology functions for the Moon remain poorly constrained for ages beyond 3.9 billion years. Here we present U–Pb geochronology of phosphate minerals within shocked lunar norites of a boulder from the Apollo 17 Station 8. These minerals record an older impact event around 4.2 billion years ago, and a younger disturbance at around 0.5 billion years ago. Based on nanoscale observations using atom probe tomography, lunar cratering records, and impact simulations, we ascribe the older event to the formation of the large Serenitatis Basin and the younger possibly to that of the Dawes crater. This suggests the Serenitatis Basin formed unrelated to or in the early stages of a protracted Late Heavy Bombardment.
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7. |
- Knox-Brown, Ben, et al.
(author)
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Isolated small airways obstruction predicts future chronic airflow obstruction : a multinational longitudinal study
- 2023
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In: BMJ Open Respiratory Research. - : BMJ Publishing Group Ltd. - 2052-4439. ; 10:1
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Journal article (peer-reviewed)abstract
- BACKGROUND: Chronic airflow obstruction is a key characteristic of chronic obstructive pulmonary disease. We investigated whether isolated small airways obstruction is associated with chronic airflow obstruction later in life.METHODS: We used longitudinal data from 3957 participants of the multinational Burden of Obstructive Lung Disease study. We defined isolated small airways obstruction using the prebronchodilator mean forced expiratory flow rate between 25% and 75% of the forced vital capacity (FVC) (FEF25-75) if a result was less than the lower limit of normal (1/FVC). We also used the forced expiratory volume in 3 s to FVC ratio (FEV3/FVC) to define small airways obstruction. We defined chronic airflow obstruction as post-bronchodilator FEV1/FVCRESULTS: Median follow-up time was 8.3 years. Chronic airflow obstruction was more likely to develop in participants with isolated small airways obstruction at baseline (FEF25-75 less than the LLN, OR: 2.95, 95% CI 1.02 to 8.54; FEV3/FVC less than the LLN, OR: 1.94, 95% CI 1.05 to 3.62). FEF25-75 was better than the FEV3/FVC ratio to discriminate future chronic airflow obstruction (AUC: 0.764 vs 0.692). Results were similar among participants of the UK Biobank study.CONCLUSION: Measurements of small airways obstruction can be used as early markers of future obstructive lung disease.
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8. |
- Lozano, Rafael, et al.
(author)
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Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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In: The Lancet. - : Elsevier. - 1474-547X .- 0140-6736. ; 392:10159, s. 2091-2138
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Journal article (peer-reviewed)abstract
- Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59·4 (IQR 35·4–67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6–14·0) to a high of 84·9 (83·1–86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030.
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9. |
- Ratanachina, Jate, et al.
(author)
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Association of respiratory symptoms and lung function with occupation in the multinational Burden of Obstructive Lung Disease (BOLD) study
- 2023
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In: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 61:1
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Journal article (peer-reviewed)abstract
- Background Chronic obstructive pulmonary disease has been associated with exposures in the workplace. We aimed to assess the association of respiratory symptoms and lung function with occupation in the Burden of Obstructive Lung Disease study.Methods We analysed cross-sectional data from 28 823 adults (≥40 years) in 34 countries. We considered 11 occupations and grouped them by likelihood of exposure to organic dusts, inorganic dusts and fumes. The association of chronic cough, chronic phlegm, wheeze, dyspnoea, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1)/FVC with occupation was assessed, per study site, using multivariable regression. These estimates were then meta-analysed. Sensitivity analyses explored differences between sexes and gross national income.Results Overall, working in settings with potentially high exposure to dusts or fumes was associated with respiratory symptoms but not lung function differences. The most common occupation was farming. Compared to people not working in any of the 11 considered occupations, those who were farmers for ≥20 years were more likely to have chronic cough (OR 1.52, 95% CI 1.19–1.94), wheeze (OR 1.37, 95% CI 1.16–1.63) and dyspnoea (OR 1.83, 95% CI 1.53–2.20), but not lower FVC (β=0.02 L, 95% CI −0.02–0.06 L) or lower FEV1/FVC (β=0.04%, 95% CI −0.49–0.58%). Some findings differed by sex and gross national income.Conclusion At a population level, the occupational exposures considered in this study do not appear to be major determinants of differences in lung function, although they are associated with more respiratory symptoms. Because not all work settings were included in this study, respiratory surveillance should still be encouraged among high-risk dusty and fume job workers, especially in low- and middle-income countries.
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10. |
- Reitsma, Marissa B., et al.
(author)
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Smoking prevalence and attributable disease burden in 195 countries and territories, 1990-2015 : a systematic analysis from the Global Burden of Disease Study 2015
- 2017
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In: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 389:10082, s. 1885-1906
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Journal article (peer-reviewed)abstract
- Background The scale-up of tobacco control, especially after the adoption of the Framework Convention for Tobacco Control, is a major public health success story. Nonetheless, smoking remains a leading risk for early death and disability worldwide, and therefore continues to require sustained political commitment. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) offers a robust platform through which global, regional, and national progress toward achieving smoking-related targets can be assessed. Methods We synthesised 2818 data sources with spatiotemporal Gaussian process regression and produced estimates of daily smoking prevalence by sex, age group, and year for 195 countries and territories from 1990 to 2015. We analysed 38 risk-outcome pairs to generate estimates of smoking-attributable mortality and disease burden, as measured by disability-adjusted life-years (DALYs). We then performed a cohort analysis of smoking prevalence by birth-year cohort to better understand temporal age patterns in smoking. We also did a decomposition analysis, in which we parsed out changes in all-cause smoking-attributable DALYs due to changes in population growth, population ageing, smoking prevalence, and risk-deleted DALY rates. Finally, we explored results by level of development using the Socio-demographic Index (SDI). Findings Worldwide, the age-standardised prevalence of daily smoking was 25.0% (95% uncertainty interval [UI] 24.2-25.7) for men and 5.4% (5.1-5.7) for women, representing 28.4% (25.8-31.1) and 34.4% (29.4-38.6) reductions, respectively, since 1990. A greater percentage of countries and territories achieved significant annualised rates of decline in smoking prevalence from 1990 to 2005 than in between 2005 and 2015; however, only four countries had significant annualised increases in smoking prevalence between 2005 and 2015 (Congo [Brazzaville] and Azerbaijan for men and Kuwait and Timor-Leste for women). In 2015, 11.5% of global deaths (6.4 million [95% UI 5.7-7.0 million]) were attributable to smoking worldwide, of which 52.2% took place in four countries (China, India, the USA, and Russia). Smoking was ranked among the five leading risk factors by DALYs in 109 countries and territories in 2015, rising from 88 geographies in 1990. In terms of birth cohorts, male smoking prevalence followed similar age patterns across levels of SDI, whereas much more heterogeneity was found in age patterns for female smokers by level of development. While smoking prevalence and risk-deleted DALY rates mostly decreased by sex and SDI quintile, population growth, population ageing, or a combination of both, drove rises in overall smoking-attributable DALYs in low-SDI to middle-SDI geographies between 2005 and 2015. Interpretation The pace of progress in reducing smoking prevalence has been heterogeneous across geographies, development status, and sex, and as highlighted by more recent trends, maintaining past rates of decline should not be taken for granted, especially in women and in low-SDI to middle-SDI countries. Beyond the effect of the tobacco industry and societal mores, a crucial challenge facing tobacco control initiatives is that demographic forces are poised to heighten smoking's global toll, unless progress in preventing initiation and promoting cessation can be substantially accelerated. Greater success in tobacco control is possible but requires effective, comprehensive, and adequately implemented and enforced policies, which might in turn require global and national levels of political commitment beyond what has been achieved during the past 25 years.
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11. |
- Rothery, David, et al.
(author)
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Mercury's surface and composition to be studied by BepiColombo
- 2010
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In: Planetary and Space Science. - : Elsevier BV. - 0032-0633 .- 1873-5088. ; 58:1-2, s. 21-39
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Journal article (peer-reviewed)abstract
- We describe the contributions that we expect the BepiColombo mission to make towards increased knowledge and understanding of Mercury's surface and composition. BepiColornbo will have a larger and more capable Suite of instruments relevant for determination of the topographic, physical, chemical and mineralogical properties of the surface than carried by NASA's MESSENGER mission. We anticipate that the insights gained into the planet's geological history and its current space weathering environment will enable us to understand the relationships between surface composition and the composition of different types of crust. This will enable estimation of the composition of the mantle from which the crust was derived, and lead to better constraints on models for Mercury's origin and the nature of the material from which it formed.
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12. |
- Snape, Joshua, et al.
(author)
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Ancient volcanism on the Moon: Insights from Pb isotopes in the MIL 13317 and Kalahari 009 lunar meteorites
- 2018
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In: Earth and Planetary Science Letters. - : Elsevier. - 0012-821X .- 1385-013X. ; 502, s. 84-95
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Journal article (peer-reviewed)abstract
- Lunar meteorites provide a potential opportunity to expand the study of ancient (>4000 Ma) basaltic volcanism on the Moon, of which there are only a few examples in the Apollo sample collection. Secondary Ion Mass Spectrometry (SIMS) was used to determine the Pb isotopic compositions of multiple mineral phases (Ca-phosphates, baddeleyite K-feldspar, K-rich glass and plagioclase) in two lunar meteorites, Miller Range (MIL) 13317 and Kalahari (Kal) 009. These data were used to calculate crystallisation ages of 4332 ± 2 Ma (95% confidence level) for basaltic clasts in MIL 13317, and 4369 ± 7 Ma (95% confidence level) for the monomict basaltic breccia Kal 009. From the analyses of the MIL 13317 basaltic clasts, it was possible to determine an initial Pb isotopic composition of the protolith from which the clasts originated, and infer a 238 U/204 Pb ratio (μ-value) of 850 ± 130 (2σ uncertainty) for the magmatic source of this basalt. This is lower than μ-values determined previously for KREEP-rich (an acronym for K, Rare Earth Elements and P) basalts, although analyses of other lithological components in the meteorite suggest the presence of a KREEP component in the regolith from which the breccia was formed and, therefore, a more probable origin for the meteorite on the lunar nearside. It was not possible to determine a similar initial Pb isotopic composition from the Kal 009 data, but previous studies of the meteorite have highlighted the very low concentrations of incompatible trace elements and proposed an origin on the farside of the Moon. Taken together, the data from these two meteorites provide more compelling evidence for widespread ancient volcanism on the Moon. Furthermore, the compositional differences between the basaltic materials in the meteorites provide evidence that this volcanism was not an isolated or localised occurrence, but happened in multiple locations on the Moon and at distinct times. In light of previous studies into early lunar magmatic evolution, these data also imply that basaltic volcanism commenced almost immediately after Lunar Magma Ocean (LMO) crystallisation, as defined by Nd, Hf and Pb model ages at about 4370 Ma.
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13. |
- Snape, Joshua F., et al.
(author)
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The timing of basaltic volcanism at the Apollo landing sites
- 2019
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In: Geochimica et Cosmochimica Acta. - 0016-7037 .- 1872-9533. ; 266, s. 29-53
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Journal article (peer-reviewed)abstract
- Precise crystallisation ages have been determined for a range of Apollo basalts from Pb-Pb isochrons generated using Secondary Ion Mass Spectrometry (SIMS) analyses of multiple accessory phases including K-feldspar, K-rich glass and phosphates. The samples analysed in this study include five Apollo 11 high-Ti basalts, one Apollo 14 high-Al basalt, seven Apollo 15 low-Ti basalts, and five Apollo 17 high-Ti basalts. Together with the samples analysed in two previous similar studies, Pb-Pb isochron ages have been determined for all of the major basaltic suites sampled during the Apollo missions. The accuracy of these ages has been assessed as part of a thorough review of existing age determinations for Apollo basalts, which reveals a good agreement with previous studies of the same samples, as well as with average ages that have been calculated for the emplacement of the different basaltic suites at the Apollo landing sites. Furthermore, the precision of the new age determinations helps to resolve distinctions between the ages of different basaltic suites in more detail than was previously possible. The proposed ages for the basaltic surface flows at the Apollo landing sites have been reviewed in light of these new sample ages. Finally, the data presented here have also been used to constrain the initial Pb isotopic compositions of the mare basalts, which indicate a significant degree of heterogeneity in the lunar mantle source regions, even among the basalts collected at individual landing sites.
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14. |
- Snape, Joshua, 1986-, et al.
(author)
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Lunar basalt chronology, mantle differentiation and implications for determining the age of the Moon
- 2016
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In: Earth and Planetary Science Letters. - : Elsevier BV. - 0012-821X .- 1385-013X. ; 451, s. 149-158
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Journal article (peer-reviewed)abstract
- Despite more than 40 years of studying Apollo samples, the age and early evolution of the Moon remain contentious. Following the formation of the Moon in the aftermath of a giant impact, the resulting Lunar Magma Ocean (LMO) is predicted to have generated major geochemically distinct silicate reservoirs, including the sources of lunar basalts. Samples of these basalts, therefore, provide a unique opportunity to characterize these reservoirs. However, the precise timing and extent of geochemical fractionation is poorly constrained, not least due to the difficulty in determining accurate ages and initial Pb isotopic compositions of lunar basalts. Application of an in situ ion microprobe approach to Pb isotope analysis has allowed us to obtain precise crystallization ages from six lunar basalts, typically with an uncertainty of about +/- 10 Ma, as well as constrain their initial Pb-isotopic compositions. This has enabled construction of a two-stage model for the Pb-isotopic evolution of lunar silicate reservoirs, which necessitates the prolonged existence of high-mu reservoirs in order to explain the very radiogenic compositions of the samples. Further, once firm constraints on U and Pb partitioning behaviour are established, this model has the potential to help distinguish between conflicting estimates for the age of the Moon. Nonetheless, we are able to constrain the timing of a lunar mantle reservoir differentiation event at 4376 +/- 18 Ma, which is consistent with that derived from the Sm-Nd and Lu-Hf isotopic systems, and is interpreted as an average estimate of the time at which the high-mu, urKREEP reservoir was established and the Ferroan Anorthosite (FAN) suite was formed.
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- Wang, Haidong, et al.
(author)
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Estimates of global, regional, and national incidence, prevalence, and mortality of HIV, 1980-2015 : the Global Burden of Disease Study 2015.
- 2016
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In: The lancet. HIV. - : Elsevier. - 2352-3018. ; 3:8, s. e361-e387
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Journal article (peer-reviewed)abstract
- BACKGROUND: Timely assessment of the burden of HIV/AIDS is essential for policy setting and programme evaluation. In this report from the Global Burden of Disease Study 2015 (GBD 2015), we provide national estimates of levels and trends of HIV/AIDS incidence, prevalence, coverage of antiretroviral therapy (ART), and mortality for 195 countries and territories from 1980 to 2015.METHODS: For countries without high-quality vital registration data, we estimated prevalence and incidence with data from antenatal care clinics and population-based seroprevalence surveys, and with assumptions by age and sex on initial CD4 distribution at infection, CD4 progression rates (probability of progression from higher to lower CD4 cell-count category), on and off antiretroviral therapy (ART) mortality, and mortality from all other causes. Our estimation strategy links the GBD 2015 assessment of all-cause mortality and estimation of incidence and prevalence so that for each draw from the uncertainty distribution all assumptions used in each step are internally consistent. We estimated incidence, prevalence, and death with GBD versions of the Estimation and Projection Package (EPP) and Spectrum software originally developed by the Joint United Nations Programme on HIV/AIDS (UNAIDS). We used an open-source version of EPP and recoded Spectrum for speed, and used updated assumptions from systematic reviews of the literature and GBD demographic data. For countries with high-quality vital registration data, we developed the cohort incidence bias adjustment model to estimate HIV incidence and prevalence largely from the number of deaths caused by HIV recorded in cause-of-death statistics. We corrected these statistics for garbage coding and HIV misclassification.FINDINGS: Global HIV incidence reached its peak in 1997, at 3·3 million new infections (95% uncertainty interval [UI] 3·1-3·4 million). Annual incidence has stayed relatively constant at about 2·6 million per year (range 2·5-2·8 million) since 2005, after a period of fast decline between 1997 and 2005. The number of people living with HIV/AIDS has been steadily increasing and reached 38·8 million (95% UI 37·6-40·4 million) in 2015. At the same time, HIV/AIDS mortality has been declining at a steady pace, from a peak of 1·8 million deaths (95% UI 1·7-1·9 million) in 2005, to 1·2 million deaths (1·1-1·3 million) in 2015. We recorded substantial heterogeneity in the levels and trends of HIV/AIDS across countries. Although many countries have experienced decreases in HIV/AIDS mortality and in annual new infections, other countries have had slowdowns or increases in rates of change in annual new infections.INTERPRETATION: Scale-up of ART and prevention of mother-to-child transmission has been one of the great successes of global health in the past two decades. However, in the past decade, progress in reducing new infections has been slow, development assistance for health devoted to HIV has stagnated, and resources for health in low-income countries have grown slowly. Achievement of the new ambitious goals for HIV enshrined in Sustainable Development Goal 3 and the 90-90-90 UNAIDS targets will be challenging, and will need continued efforts from governments and international agencies in the next 15 years to end AIDS by 2030.
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