114 research outputs found

    Coral-reef-derived dimethyl sulfide and the climatic impact of the loss of coral reefs

    Get PDF
    Dimethyl sulfide (DMS) is a naturally occurring aerosol precursor gas which plays an important role in the global sulfur budget, aerosol formation and climate. While DMS is produced predominantly by phytoplankton, recent observational literature has suggested that corals and their symbionts produce a comparable amount of DMS, which is unaccounted for in models. It has further been hypothesised that the coral reef source of DMS may modulate regional climate. This hypothesis presents a particular concern given the current threat to coral reefs under anthropogenic climate change. In this paper, a global climate model with online chemistry and aerosol is used to explore the influence of coral-reef-derived DMS on atmospheric composition and climate. A simple representation of coral-reef-derived DMS is developed and added to a common DMS surface water climatology, resulting in an additional flux of 0.3 Tg yr−1 S, or 1.7 % of the global sulfur flux from DMS. By comparing the differences between both nudged and free-running ensemble simulations with and without coral-reef-derived DMS, the influence of coral-reef-derived DMS on regional climate is quantified. In the Maritime Continent–Australian region, where the highest density of coral reefs exists, a small decrease in nucleation- and Aitken-mode aerosol number concentration and mass is found when coral reef DMS emissions are removed from the system. However, these small responses are found to have no robust effect on regional climate via direct and indirect aerosol effects. This work emphasises the complexities of the aerosol–climate system, and the limitations of current modelling capabilities are highlighted, in particular surrounding convective responses to changes in aerosol. In conclusion, we find no robust evidence that coral-reef-derived DMS influences global and regional climate

    Entrepreneurial sons, patriarchy and the Colonels' experiment in Thessaly, rural Greece

    Get PDF
    Existing studies within the field of institutional entrepreneurship explore how entrepreneurs influence change in economic institutions. This paper turns the attention of scholarly inquiry on the antecedents of deinstitutionalization and more specifically, the influence of entrepreneurship in shaping social institutions such as patriarchy. The paper draws from the findings of ethnographic work in two Greek lowland village communities during the military Dictatorship (1967–1974). Paradoxically this era associated with the spread of mechanization, cheap credit, revaluation of labour and clear means-ends relations, signalled entrepreneurial sons’ individuated dissent and activism who were now able to question the Patriarch’s authority, recognize opportunities and act as unintentional agents of deinstitutionalization. A ‘different’ model of institutional change is presented here, where politics intersects with entrepreneurs, in changing social institutions. This model discusses the external drivers of institutional atrophy and how handling dissensus (and its varieties over historical time) is instrumental in enabling institutional entrepreneurship

    Theorems on existence and global dynamics for the Einstein equations

    Get PDF
    This article is a guide to theorems on existence and global dynamics of solutions of the Einstein equations. It draws attention to open questions in the field. The local-in-time Cauchy problem, which is relatively well understood, is surveyed. Global results for solutions with various types of symmetry are discussed. A selection of results from Newtonian theory and special relativity that offer useful comparisons is presented. Treatments of global results in the case of small data and results on constructing spacetimes with prescribed singularity structure or late-time asymptotics are given. A conjectural picture of the asymptotic behaviour of general cosmological solutions of the Einstein equations is built up. Some miscellaneous topics connected with the main theme are collected in a separate section.Comment: Submitted to Living Reviews in Relativity, major update of Living Rev. Rel. 5 (2002)

    Young people’s awareness of the timing and placement of gambling advertising on traditional and social media platforms: a study of 11–16-year-olds in Australia

    Get PDF
    Background Research has demonstrated that the promotion of gambling, particularly within sport, may have a significant impact on positively shaping young people’s attitudes towards gambling. While some governments have implemented restrictions to limit young people’s exposure to gambling advertising, few studies have investigated where young people recall seeing gambling advertising, and whether they perceive that advertising restrictions have gone far enough in reducing exposure to these promotions. Method Mixed methods, interviewer-assisted surveys were conducted with n = 111 young people aged 11–16 years, who were self-reported fans of basketball in Victoria, Australia. Interviews were conducted at basketball stadiums between May and July 2018. The study assessed media viewing patterns; recall and awareness of the timing, placement, and content of gambling advertising; the impact of gambling advertising restrictions; and attitudes towards sporting organisations’ roles in the promotion of gambling. Results The majority of young people recalled seeing gambling advertising on television (n = 101, 91.0%), with most recalling advertising within sporting matches or games (n = 79, 71.2%). Most young people recalled seeing gambling advertising in the early evening before 8:30 pm (n = 75, 67.6%). Just over half of young people described seeing gambling advertisements on social media (n = 61, 55.0%), and over a third (n = 40, 36.0%) recalled gambling advertising on YouTube, predominantly before watching sporting or gaming videos. The majority stated that they continued to watch sport after 8:30 pm (n = 93, 83.7%), which is when restrictions on advertising in live sport in Australia end. The majority (n = 88, 79.3%) stated that there were too many gambling advertisements in sport. Three quarters believed that sporting codes should do more to prevent young people from being exposed to advertising for gambling in sport (n = 84, 75.7%). Conclusions There is now a clear body evidence that current regulatory systems for gambling advertising are ineffective, with further restrictions urgently needed across a range of media channels to prevent exposure to promotions that may encourage young people’s interest and involvement in gambling

    Understanding ‘saturation’ of radar signals over forests

    Get PDF
    There is an urgent need to quantify anthropogenic influence on forest carbon stocks. Using satellite-based radar imagery for such purposes has been challenged by the apparent loss of signal sensitivity to changes in forest aboveground volume (AGV) above a certain ‘saturation’ point. The causes of saturation are debated and often inadequately addressed, posing a major limitation to mapping AGV with the latest radar satellites. Using ground- and lidar-measurements across La Rioja province (Spain) and Denmark, we investigate how various properties of forest structure (average stem height, size and number density; proportion of canopy and understory cover) simultaneously influence radar backscatter. It is found that increases in backscatter due to changes in some properties (e.g. increasing stem sizes) are often compensated by equal magnitude decreases caused by other properties (e.g. decreasing stem numbers and increasing heights), contributing to the apparent saturation of the AGV-backscatter trend. Thus, knowledge of the impact of management practices and disturbances on forest structure may allow the use of radar imagery for forest biomass estimates beyond commonly reported saturation points

    Short-Lived Trace Gases in the Surface Ocean and the Atmosphere

    Get PDF
    The two-way exchange of trace gases between the ocean and the atmosphere is important for both the chemistry and physics of the atmosphere and the biogeochemistry of the oceans, including the global cycling of elements. Here we review these exchanges and their importance for a range of gases whose lifetimes are generally short compared to the main greenhouse gases and which are, in most cases, more reactive than them. Gases considered include sulphur and related compounds, organohalogens, non-methane hydrocarbons, ozone, ammonia and related compounds, hydrogen and carbon monoxide. Finally, we stress the interactivity of the system, the importance of process understanding for modeling, the need for more extensive field measurements and their better seasonal coverage, the importance of inter-calibration exercises and finally the need to show the importance of air-sea exchanges for global cycling and how the field fits into the broader context of Earth System Science

    Thoracic dysfunction in whiplash associated disorders: A systematic review

    Get PDF
    © 2018 Heneghan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background Research investigating Whiplash Associated Disorder (WAD) has largely focused on the cervical spine yet symptoms can be widespread. Thoracic spine pain prevalence is reported ~66%; perhaps unsurprising given the forceful stretch/eccentric loading of posterior structures of the spine, and the thoracic spine’s contribution to neck mobility/function. Approximately 50% WAD patients develop chronic pain and disability resulting in high levels of societal and healthcare costs. It is time to look beyond the cervical spine to fully understand anatomical dysfunction in WAD and provide new directions for clinical practice and research. Purpose To evaluate the scope and nature of dysfunction in the thoracic region in patients with WAD. Methods A systematic review and data synthesis was conducted according to a pre-defined, registered (PROSPERO, CRD42015026983) and published protocol. All forms of observational study were included. A sensitive topic-based search strategy was designed from inception to 1/06/16. Databases, grey literature and registers were searched using a study population terms and key words derived from scoping search. Two reviewers independently searched information sources, assessed studies for inclusion, extracted data and assessed risk of bias. A third reviewer checked for consistency and clarity. Extracted data included summary data: sample size and characteristics, outcomes, and timescales to reflect disorder state. Risk of bias was assessed using the Newcastle-Ottawa Scale. Data were tabulated to allow enabling a semi-qualitative comparison and grouped by outcome across studies. Strength of the overall body of evidence was assessed using a modified GRADE. Results Thirty eight studies (n>50,000) which were conducted across a range of countries were included. Few authors responded to requests for further data (5 of 9 contacted). Results were reported in the context of overall quality and were presented for measures of pain or dysfunction and presented, where possible, according to WAD severity and time point post injury. Key findings include: 1) high prevalence of thoracic pain (>60%); higher for those with more severe presentations and in the acute stage, 2) low prevalence of chest pain
    • …
    corecore