1,472 research outputs found

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

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    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

    Twisting arms and sending messages: Terrorist tactics in civil war

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    We examine the strategic rationale for terrorist tactics in civil war. We identify conditions that favor terrorism as a tactic in armed civil conflicts as well as the specific targets as a function of rebel characteristics, goals, and government responses to political demands. Terrorist tactics can be helpful as an instrument to coerce the government in asymmetric conflicts, as rebels are typically weak relative to the government. But terrorism can also help communicate the goals and resolve of a group when there is widespread uncertainty. We consider the strategic importance and rationale for terrorism in terms of the frequency of attacks and specific targets, and analyze our propositions using new data linking actors from the Uppsala/PRIO Armed Conflict Data and the Global Terrorism Database. Consistent with our expectations, we find that terrorism is used more extensively in civil conflicts by weaker groups and when attacks can help the group convey its goals without undermining popular support. Groups with more inclusive audiences are more likely to focus on ‘hard’ or official targets, while groups with more sectarian audiences are more likely to attack ‘soft’ targets and civilians

    Systematic review and consensus definitions for the Standardised Endpoints in Perioperative Medicine initiative: patient-centred outcomes

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    BACKGROUND: Patient-centred outcomes are increasingly used in perioperative clinical trials. The Standardised Endpoints in Perioperative Medicine (StEP) initiative aims to define which measures should be used in future research to facilitate comparison between studies and to enable robust evidence synthesis. METHODS: A systematic review was conducted to create a longlist of patient satisfaction, health-related quality of life, functional status, patient well-being, and life-impact measures for consideration. A three-stage Delphi consensus process involving 89 international experts was then conducted in order to refine this list into a set of recommendations. RESULTS: The literature review yielded six patient-satisfaction measures, seven generic health-related quality-of-life measures, eight patient well-being measures, five functional-status measures, and five life-impact measures for consideration. The Delphi response rates were 92%, 87%, and 100% for Rounds 1, 2, and 3, respectively. Three additional measures were added during the Delphi process as a result of contributions from the StEP group members. Firm recommendations have been made about one health-related quality-of-life measure (EuroQol 5 Dimension, five-level version with visual analogue scale), one functional-status measure (WHO Disability Assessment Schedule version 2.0, 12-question version), and one life-impact measure (days alive and out of hospital at 30 days after surgery). Recommendations with caveats have been made about the Bauer patient-satisfaction measure and two life-impact measures (days alive and out of hospital at 1 yr after surgery, and discharge destination). CONCLUSIONS: Several patient-centred outcome measures have been recommended for use in future perioperative studies. We suggest that every clinical study should consider using at least one patient-centred outcome within a suite of endpoints

    Development of an international standard set of outcome measures for patients with atrial fibrillation: a report of the International Consortium for Health Outcomes Measurement (ICHOM) atrial fibrillation working group.

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    AIMS: As health systems around the world increasingly look to measure and improve the value of care that they provide to patients, being able to measure the outcomes that matter most to patients is vital. To support the shift towards value-based health care in atrial fibrillation (AF), the International Consortium for Health Outcomes Measurement (ICHOM) assembled an international Working Group (WG) of 30 volunteers, including health professionals and patient representatives to develop a standardized minimum set of outcomes for benchmarking care delivery in clinical settings. METHODS AND RESULTS: Using an online-modified Delphi process, outcomes important to patients and health professionals were selected and categorized into (i) long-term consequences of disease outcomes, (ii) complications of treatment outcomes, and (iii) patient-reported outcomes. The WG identified demographic and clinical variables for use as case-mix risk adjusters. These included baseline demographics, comorbidities, cognitive function, date of diagnosis, disease duration, medications prescribed and AF procedures, as well as smoking, body mass index (BMI), alcohol intake, and physical activity. Where appropriate, and for ease of implementation, standardization of outcomes and case-mix variables was achieved using ICD codes. The standard set underwent an open review process in which over 80% of patients surveyed agreed with the outcomes captured by the standard set. CONCLUSION: Implementation of these consensus recommendations could help institutions to monitor, compare and improve the quality and delivery of chronic AF care. Their consistent definition and collection, using ICD codes where applicable, could also broaden the implementation of more patient-centric clinical outcomes research in AF

    Prognostic significance of IL-6 and IL-8 ascites levels in ovarian cancer patients

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    <p>Abstract</p> <p>Background</p> <p>The acellular fraction of epithelial ovarian cancer (EOC) ascites promotes <it>de novo </it>resistance of tumor cells and thus supports the idea that tumor cells may survive in the surrounding protective microenvironment contributing to disease recurrence. Levels of the pro-inflammatory cytokines IL-6 and IL-8 are elevated in EOC ascites suggesting that they could play a role in tumor progression.</p> <p>Methods</p> <p>We measured IL-6 and IL-8 levels in the ascites of 39 patients with newly diagnosed EOC. Commercially available enzyme-linked immunosorbent assay (ELISA) was used to determine IL-6 and IL-8 ascites levels. Ascites cytokine levels were correlated with clinicopathological parameters and progression-free survival.</p> <p>Results</p> <p>Mean ascites levels for IL-6 and IL-8 were 6419 pg/ml (SEM: 1409 pg/ml) and 1408 pg/ml (SEM: 437 pg/ml) respectively. The levels of IL-6 and IL-8 in ascites were significantly lower in patients that have received prior chemotherapy before the surgery (Mann-Whitney U test, <it>P </it>= 0.037 for IL-6 and <it>P </it>= 0.008 for IL-8). Univariate analysis revealed that high IL-6 ascites levels (<it>P </it>= 0.021), serum CA125 levels (<it>P </it>= 0.04) and stage IV (<it>P </it>= 0.009) were significantly correlated with shorter progression-free survival. Including these variables in a multivariate analysis revealed that elevated IL-6 levels (<it>P </it>= 0.033) was an independent predictor of shorter progression-free survival.</p> <p>Conclusion</p> <p>Elevated IL-6, but not IL-8, ascites level is an independent predictor of shorter progression-free survival.</p

    Attribution of extreme events to climate change in the Australian region – A review

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    Extreme event attribution is a rapidly growing field of climate science with important implications for public and government understanding of human-induced climate change. However, there is substantial variation in how well events can be attributed to human-induced climate change, depending on the nature of the event. Focusing on Australia: at one end of the scale, large-scale heat events on both the land and in the ocean are well suited to attribution studies because climate models simulate them reasonably well, there are high-quality observations available and our understanding of the processes that lead to extreme heat events is reasonably well developed. At the other end of the scale, very important phenomenon such as changes in east coast lows, severe convective storms and long-term droughts are less well observed, are beyond our current capability to robustly simulate in climate models and the complex mechanisms that lead to intensification are not well understood. Thus, some important extreme events can be linked to human-induced climate change, with a high degree of confidence, while others cannot. We review the state of the science relevant to event attribution with a focus on Australia. We highlight where progress can be made, focusing on observations, physical understanding, and realistic climate modelling

    Current quark mass dependence of nucleon magnetic moments and radii

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    A calculation of the current-quark-mass-dependence of nucleon static electromagnetic properties is necessary in order to use observational data as a means to place constraints on the variation of Nature's fundamental parameters. A Poincare' covariant Faddeev equation, which describes baryons as composites of confined-quarks and -nonpointlike-diquarks, is used to calculate this dependence The results indicate that, like observables dependent on the nucleons' magnetic moments, quantities sensitive to their magnetic and charge radii, such as the energy levels and transition frequencies in Hydrogen and Deuterium, might also provide a tool with which to place limits on the allowed variation in Nature's constants.Comment: 23 pages, 2 figures, 4 tables, 4 appendice
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