Wave radiation in simple geophysical models

Wave radiation is an important process in many geophysical flows. In particular, it is by wave radiation that flows may adjust to a state for which the dynamics is slow. Such a state is described as “balanced”, meaning there is an approximate balance between the Coriolis force and horizontal pressure gradients, and between buoyancy and vertical pressure gradients. In this thesis, wave radiation processes relevant to these enormously complex flows are studied through the use of some highly simplified models, and a parallel aim is to develop accurate numerical techniques for doing so. This thesis is divided into three main parts. 1. We consider accurate numerical boundary conditions for various equations which support wave radiation to infinity. Particular attention is given to discretely non-reflecting boundary conditions, which are derived directly from a discretised scheme. Such a boundary condition is studied in the case of the 1-d Klein-Gordon equation. The limitations concerning the practical implementation of this scheme are explored and some possible improvements are suggested. A stability analysis is developed which yields a simple stability criterion that is useful when tuning the boundary condition. The practical use of higher-order boundary conditions for the 2-d shallow water equations is also explored; the accuracy of such a method is assessed when combined with a particular interior scheme, and an analysis based on matrix pseudospectra reveals something of the stability of such a method. 2. Large-scale atmospheric and oceanic flows are examples of systems with a wide timescale separation, determined by a small parameter. In addition they both undergo constant random forcing. The five component Lorenz-Krishnamurthy system is a system with a timescale separation controlled by a small parameter, and we employ it as a model of the forced ocean by further adding a random forcing of the slow variables, and introduce wave radiation to infinity by the addition of a dispersive PDE. The dynamics are reduced by deriving balance relations, and numerical experiments are used to assess the effects of energy radiation by fast waves. 3. We study quasimodes, which demonstrate the existence of associated Landau poles of a system. In this thesis, we consider a simple model of wave radiation that exhibits quasimodes, that allows us to derive some explicit analytical results, as opposed to physically realistic geophysical fluid systems for which such results are often unavailable, necessitating recourse to numerical techniques. The growth rates obtained for this system, which is an extension of one considered by Lamb, are confirmed using numerical experiments

Government revenue, quality of governance and child and maternal survival

Funding: Global Challenges Research Fund / Prof Sonia Buist Global Child Health Research Fund / Scottish Funding Council.This paper considers the effect of government revenue and the quality of governance on the under-five and maternal survival rates. A non-linear panel data study was undertaken using annual data for every country in the world. The study's broad conclusion is that while government resources, measured as total revenue received by a country's government, is essential, the quality of governance is even more critical in determining a good outcome for both mother and child.Publisher PDFPeer reviewe

Tax expenditures and progress to the Sustainable Development Goals

Action Aid International Professor Sonia Buist Global Child Health Research Fund Scottish Funding CounciThis study reports the impact of governments having additional revenue equivalent to tax expenditures on achieving the Sustainable Development Goals in 97 countries. The study draws data on revenue foregone from the Global Tax Expenditure Database. To analyze the potential of an increase in government revenue equivalent to the revenue foregone, the study uses the Government Revenue and Development Estimations modeling. The study finds that if governments had additional revenue equivalent to tax expenditures: an additional 17 million children would attend school (13.62% currently out of school), an additional 70 million people would use basic water (23% of those without access), 146 million would use basic sanitation (20% of those without access), 181,000 children would survive (13% of children who currently die), and 12,000 mothers would survive (16% of mothers who currently die). Critically, there would be improvements in governance indicators in all regions. Foregone revenue from tax expenditures could increase access to public services for millions, which is the most effective tool for reducing inequality and driving progress toward sustainable development. The massive opportunity costs reported here require all governments to report and justify their annual tax expenditure.Peer reviewe

Tax abuse – the potential for the Sustainable Development Goals

Funding: The Scottish Funding Council, the Global Challenges Research Fund, and the Professor Sonia Buist Global Child Health Research Fund provide funding for the GRADE project.Governments generally provide the services that allow people to access the critical determinants of health: water, sanitation, and education. These are also Sustainable Development Goals and fundamental economic and social human rights. Studies show that governments spend more on public services and health determinants with more revenue. However, governments in low and lower-middle-income countries have small budgets, and tax abuse (avoidance and evasion) contributes to revenue leaks. Researchers have estimated that four countries enable more than half of global tax abuse. We used estimates on tax abuse with a model of the relationship between government revenue and the determinants of health to quantify the potential for progress towards the Sustainable Development Goals 3, 4, 5, and 6. The increase in government revenue equivalent to global tax abuses is associated with 36 million people having access to basic sanitation and 18 million having access to basic drinking water. Additionally, over a ten year period, this increase would be associated with over 600,000 children and almost 80,000 mothers surviving. Thus, curtailing tax abuses would significantly contribute to progress towards the Sustainable Development Goals. Countries that enable tax abuses must review and modify policies to ensure progress towards these goals.Publisher PDFPeer reviewe

Government revenue and child and maternal mortality

Funding: The Global Challenges Research Fund, the Scottish Funding Council and the Professor Sonia Buist Global Health Research Fund.Most maternal and child deaths result from inadequate access to the critical determinants of health: clean water, sanitation, education and healthcare, which are also among the Sustainable Development Goals. Reasons for poor access include insufficient government revenue for essential public services. In this paper, we predict the reductions in mortality rates — both child and maternal — that could result from increases in government revenue, using panel data from 191 countries and a two-way fixed-effect linear regression model. The relationship between government revenue per capita and mortality rates is highly non-linear, and the best form of non-linearity we have found is a version of an inverse function. This implies that countries with small per-capita government revenues have a better scope for reducing mortality rates. However, as per-capita revenue rises, the possible gains decline rapidly in a non-linear way. We present the results which show the potential decrease in mortality and lives saved for each of the 191 countries if government revenue increases. For example, a 10% increase in per-capita government revenue in Afghanistan in 2002 ($24.49 million) is associated with a reduction in the under-5 mortality rate by 12.35 deaths per 1000 births and 13,094 lives saved. This increase is associated with a decrease in the maternal mortality ratio of 9.3 deaths per 100,000 live births and 99 maternal deaths averted. Increasing government revenue can directly impact mortality, especially in countries with low per- capita government revenues. The results presented in this study could be used for economic, social and governance reporting by multinational companies and for evidence-based policymaking and advocacy.Publisher PDFPeer reviewe

The NASA Time-Resolved Observations of Precipitation Structure and Storm Intensity with a Constellation of Smallsats (TROPICS) Mission: Results from the Pathfinder Demonstration and Look Ahead to the Constellation Mission

The NASA Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission will provide nearly all-weather observations of 3-D temperature and humidity, as well as cloud ice and precipitation horizontal structure, at high temporal resolution to conduct high-value science investigations of tropical cyclones. TROPICS will provide rapid-refresh microwave measurements (median refresh rate of approximately 50 minutes for the baseline mission) over the tropics that can be used to observe the thermodynamics of the troposphere and precipitation structure for storm systems at the mesoscale and synoptic scale over the entire storm lifecycle. The TROPICS constellation mission comprises six CubeSats in three low-Earth orbital planes. Each CubeSat will host a high-performance radiometer to provide temperature profiles using seven channels near the 118.75 GHz oxygen absorption line, water vapor profiles using three channels near the 183 GHz water vapor absorption line, imagery in a single channel near 90 GHz for precipitation measurements (when combined with higher resolution water vapor channels), and a single channel at 205 GHz that is more sensitive to precipitation-sized ice particles. TROPICS spatial resolution and measurement sensitivity is comparable with current state-of-the-art observing platforms. Launches for the TROPICS constellation mission are planned in 2022. NASA’s Earth System Science Pathfinder (ESSP) Program Office approved the separate TROPICS Pathfinder mission, which launched into a sun-synchronous orbit (2:00pm LTDN, 530 km) on June 30, 2021, in advance of the TROPICS constellation mission as a technology demonstration and risk reduction effort. The TROPICS Pathfinder mission has provided an opportunity to checkout and optimize all mission elements prior to the primary constellation mission. In this paper, we describe the instrument checkout and calibration/validation plans and progress for the TROPICS Pathfinder mission and discuss first light mission results. All spacecraft and radiometer systems are fully operational as of Launch + 11 months

Impact of fatigue as the primary determinant of functional limitations among patients with post-COVID-19 syndrome: a cross-sectional observational study

OBJECTIVES: To describe self-reported characteristics and symptoms of treatment-seeking patients with post-COVID-19 syndrome (PCS). To assess the impact of symptoms on health-related quality of life (HRQoL) and patients' ability to work and undertake activities of daily living. DESIGN: Cross-sectional single-arm service evaluation of real-time user data. SETTING: 31 post-COVID-19 clinics in the UK. PARTICIPANTS: 3754 adults diagnosed with PCS in primary or secondary care deemed suitable for rehabilitation. INTERVENTION: Patients using the Living With Covid Recovery digital health intervention registered between 30 November 2020 and 23 March 2022. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the baseline Work and Social Adjustment Scale (WSAS). WSAS measures the functional limitations of the patient; scores of ≥20 indicate moderately severe limitations. Other symptoms explored included fatigue (Functional Assessment of Chronic Illness Therapy-Fatigue), depression (Patient Health Questionnaire-Eight Item Depression Scale), anxiety (Generalised Anxiety Disorder Scale, Seven-Item), breathlessness (Medical Research Council Dyspnoea Scale and Dyspnoea-12), cognitive impairment (Perceived Deficits Questionnaire, Five-Item Version) and HRQoL (EQ-5D). Symptoms and demographic characteristics associated with more severe functional limitations were identified using logistic regression analysis. RESULTS: 3541 (94%) patients were of working age (18-65); mean age (SD) 48 (12) years; 1282 (71%) were female and 89% were white. 51% reported losing ≥1 days from work in the previous 4 weeks; 20% reported being unable to work at all. Mean WSAS score at baseline was 21 (SD 10) with 53% scoring ≥20. Factors associated with WSAS scores of ≥20 were high levels of fatigue, depression and cognitive impairment. Fatigue was found to be the main symptom contributing to a high WSAS score. CONCLUSION: A high proportion of this PCS treatment-seeking population was of working age with over half reporting moderately severe or worse functional limitation. There were substantial impacts on ability to work and activities of daily living in people with PCS. Clinical care and rehabilitation should address the management of fatigue as the dominant symptom explaining variation in functionality

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy