Quantifying the combined effects of multiple extreme floods on river channel geometry and on flood hazards

Effects of flood-induced bed elevation and channel geometry changes on flood hazards are largely unexplored, especially in the case of multiple floods from the same site. This study quantified the evolution of river channel and floodplain geometry during a repeated series of hypothetical extreme floods using a 2D full hydro-morphodynamic model (LHMM). These experiments were designed to examine the consequences of channel geometry changes on channel conveyance capacity and subsequent flood dynamics. Our results revealed that extreme floods play an important role in adjusting a river channel to become more efficient for subsequent propagation of floods, and that in-channel scour and sediment re-distribution can greatly improve the conveyance capacity of a channel for subsequent floods. In our hypothetical sequence of floods the response of bed elevation was of net degradation, and sediment transport successively weakened even with floods of the same magnitude. Changes in river channel geometry led to significant impact on flood hydraulics and thereby flood hazards. We found that flood-induced in-channel erosion can disconnect the channel from its floodplain resulting in a reduction of floodwater storage. Thus, the frequency and extent of subsequent overbank flows and floodplain inundation decreased, which reduced downstream flood attenuation and increased downstream flood hazard. In combination and in summary, these results suggest that changes in channel capacity due to extreme floods may drive changes in flood hazard. The assumption of unchanging of river morphology during inundation modelling should therefore be open to question for flood risk management

Body fatness and sex steroid hormone concentrations in US men: results from NHANES III

OBJECTIVE: Obesity is associated with a variety of chronic diseases, including cancer, which may partly be explained by its influence on sex steroid hormone concentrations. Whether different measures of obesity, i.e., body mass index (BMI), waist circumference, and percent body fat were differentially associated with circulating levels of sex steroid hormones was examined in 1,265 men, aged 20-90+ years old, attending the morning examination session of the Third National Health and Nutrition Examination Survey (NHANES III). MATERIALS AND METHODS: Serum hormones were measured by immunoassay. Weight, height, and waist circumference were measured by trained staff. Percent body fat was estimated from bioelectrical impedance. Multivariate linear regression was used to estimate associations between body fatness measures and hormone levels. RESULTS: Total and free testosterone and sex hormone binding globulin concentrations decreased, whereas total and free estradiol increased with increasing BMI, waist circumference, and percent body fat (all p trend < 0.05). The magnitude of change in these hormones was similar for a one-quartile increase in each body fatness measure. CONCLUSION: Measured BMI, waist circumference, and percent body fat led to similar inferences about their association with hormone levels in men

An Overview on Principles for Energy Efficient Robot Locomotion.

Despite enhancements in the development of robotic systems, the energy economy of today's robots lags far behind that of biological systems. This is in particular critical for untethered legged robot locomotion. To elucidate the current stage of energy efficiency in legged robotic systems, this paper provides an overview on recent advancements in development of such platforms. The covered different perspectives include actuation, leg structure, control and locomotion principles. We review various robotic actuators exploiting compliance in series and in parallel with the drive-train to permit energy recycling during locomotion. We discuss the importance of limb segmentation under efficiency aspects and with respect to design, dynamics analysis and control of legged robots. This paper also reviews a number of control approaches allowing for energy efficient locomotion of robots by exploiting the natural dynamics of the system, and by utilizing optimal control approaches targeting locomotion expenditure. To this end, a set of locomotion principles elaborating on models for energetics, dynamics, and of the systems is studied

Impacts of AKST on development and sustainability goals

The International Assessment of Agricultural Knowledge, Science, and Technology for Development (IAASTD) looks realistically at how we could effectively use agriculture/AKST to help us meet development and sustainability goals. An unprecedented three-year collaborative effort, the IAASTD involved more than 400 authors in 110 countries and cost more than $11 million. It reports on the advances and setbacks of the past fifty years and offers options for the next fifty years. The results of the project are contained in seven reports: a Global Report, five regional Sub-Global Assessments, and a Synthesis Report. The Global Report gives the key findings of the Assessment, and the five Sub-Global Assessments address regional challenges. The volumes present options for action. All of the reports have been extensively peer-reviewed by governments and experts and all have been approved by a panel of participating governments. The Sub-Global Assessments all utilize a similar and consistent framework: examining and reporting on the impacts of AKST on hunger, poverty, nutrition, human health, and environmental/social sustainability. The IAASTD was initiated by the World Bank and the United Nations Food and Agricultural Organization, with support from the World Bank, the World Health Organization, and other sponsors. Its goal is to analyze the potential of agricultural knowledge, science, and technology (AKST) for reducing hunger and poverty, improving rural livelihoods, and working toward environmentally, socially, and economically sustainable development

Impacts of AKST on development and sustainability goals

The International Assessment of Agricultural Knowledge, Science, and Technology for Development (IAASTD) looks realistically at how we could effectively use agriculture/AKST to help us meet development and sustainability goals. An unprecedented three-year collaborative effort, the IAASTD involved more than 400 authors in 110 countries and cost more than $11 million. It reports on the advances and setbacks of the past fifty years and offers options for the next fifty years. The results of the project are contained in seven reports: a Global Report, five regional Sub-Global Assessments, and a Synthesis Report. The Global Report gives the key findings of the Assessment, and the five Sub-Global Assessments address regional challenges. The volumes present options for action. All of the reports have been extensively peer-reviewed by governments and experts and all have been approved by a panel of participating governments. The Sub-Global Assessments all utilize a similar and consistent framework: examining and reporting on the impacts of AKST on hunger, poverty, nutrition, human health, and environmental/social sustainability. The IAASTD was initiated by the World Bank and the United Nations Food and Agricultural Organization, with support from the World Bank, the World Health Organization, and other sponsors. Its goal is to analyze the potential of agricultural knowledge, science, and technology (AKST) for reducing hunger and poverty, improving rural livelihoods, and working toward environmentally, socially, and economically sustainable development

Global prevalence, treatment, and prevention of hepatitis B virus infection in 2016: a modelling study

BACKGROUND: The 69th World Health Assembly approved the Global Health Sector Strategy to eliminate viral hepatitis by 2030. Although no virological cure exists for hepatitis B virus (HBV) infection, existing therapies to control viral replication and prophylaxis to minimise mother-to-child transmission make elimination of HBV feasible. We aimed to estimate the national, regional, and global prevalence of HBsAg in the general population and in the population aged 5 years in 2016, as well as coverage of prophylaxis, diagnosis, and treatment. METHODS: In this modelling study, we used a Delphi process that included a literature review in PubMed and Embase, followed by interviews with experts, to quantify the historical epidemiology of HBV infection. We then used a dynamic HBV transmission and progression model to estimate the country-level and regional-level prevalence of HBsAg in 2016 and the effect of prophylaxis and treatment on disease burden. FINDINGS: We developed models for 120 countries, 78 of which were populated with data approved by experts. Using these models, we estimated that the global prevalence of HBsAg in 2016 was 3·9% (95% uncertainty interval [UI] 3·4-4·6), corresponding to 291 992 000 (251 513 000-341 114 000) infections. Of these infections, around 29 million (10%) were diagnosed, and only 4·8 million (5%) of 94 million individuals eligible for treatment actually received antiviral therapy. Around 1·8 (1·6-2·2) million infections were in children aged 5 years, with a prevalence of 1·4% (1·2-1·6). We estimated that 87% of infants had received the three-dose HBV vaccination in the first year of life, 46% had received timely birth-dose vaccination, and 13% had received hepatitis B immunoglobulin along with the full vaccination regimen. Less than 1% of mothers with a high viral load had received antiviral therapy to reduce mother-to-child transmission. INTERPRETATION: Our estimate of HBV prevalence in 2016 differs from previous studies, potentially because we took into account the effect of infant prophylaxis and early childhood vaccination, as well as changing prevalence over time. Although some regions are well on their way to meeting prophylaxis and prevalence targets, all regions must substantially scale-up access to diagnosis and treatment to meet the global targets. FUNDING: John C Martin Foundation.status: publishe

Global prevalence, treatment, and prevention of hepatitis B virus infection in 2016: a modelling study

Background: The 69th World Health Assembly approved the Global Health Sector Strategy to eliminate viral hepatitis by 2030. Although no virological cure exists for hepatitis B virus (HBV) infection, existing therapies to control viral replication and prophylaxis to minimise mother-to-child transmission make elimination of HBV feasible. We aimed to estimate the national, regional, and global prevalence of HBsAg in the general population and in the population aged 5 years in 2016, as well as coverage of prophylaxis, diagnosis, and treatment. Methods: In this modelling study, we used a Delphi process that included a literature review in PubMed and Embase, followed by interviews with experts, to quantify the historical epidemiology of HBV infection. We then used a dynamic HBV transmission and progression model to estimate the country-level and regional-level prevalence of HBsAg in 2016 and the effect of prophylaxis and treatment on disease burden. Findings: We developed models for 120 countries, 78 of which were populated with data approved by experts. Using these models, we estimated that the global prevalence of HBsAg in 2016 was 3·9% (95% uncertainty interval [UI] 3·4–4·6), corresponding to 291 992 000 (251 513 000–341 114 000) infections. Of these infections, around 29 million (10%) were diagnosed, and only 4·8 million (5%) of 94 million individuals eligible for treatment actually received antiviral therapy. Around 1·8 (1·6–2·2) million infections were in children aged 5 years, with a prevalence of 1·4% (1·2–1·6). We estimated that 87% of infants had received the three-dose HBV vaccination in the first year of life, 46% had received timely birth-dose vaccination, and 13% had received hepatitis B immunoglobulin along with the full vaccination regimen. Less than 1% of mothers with a high viral load had received antiviral therapy to reduce mother-to-child transmission. Interpretation: Our estimate of HBV prevalence in 2016 differs from previous studies, potentially because we took into account the effect of infant prophylaxis and early childhood vaccination, as well as changing prevalence over time. Although some regions are well on their way to meeting prophylaxis and prevalence targets, all regions must substantially scale-up access to diagnosis and treatment to meet the global targets. Funding: John C Martin Foundation