120 research outputs found

    Charge Correlation in Near Side Hadron-Hadron Jets at sqrt(sNN)=200GeV in PHENIX

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    We analyze the relative azimuthal (Δϕ\Delta\phi) distribution of same-charge and opposite-charge particle pairs. We then remove elliptic flow background using the ZYAM method. Comparisons between near angle Δϕ\Delta\phi peak widths are presented for various centralities.Comment: Poster Proceedings from 2005 Quark Matter Conference. 4 Pages, 4 Figure

    Simulation and observations of stratospheric aerosols from the 2009 Sarychev volcanic eruption

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    We used a general circulation model of Earth’s climate to conduct simulations of the 12-16 June 2009 eruption of Sarychev volcano (48.1°N, 153.2°E). The model simulates the formation and transport of the stratospheric sulfate aerosol cloud from the eruption and the resulting climate response. We compared optical depth results from these simulations with limb scatter measurements from the Optical Spectrograph and InfraRed Imaging System (OSIRIS), in situ measurements from balloon-borne instruments lofted from Laramie, Wyoming (41.3°N, 105.7°W), and five lidar stations located throughout the Northern Hemisphere. The aerosol cloud covered most of the Northern Hemisphere, extending slightly into the tropics, with peak backscatter measured between 12 and 16 km in altitude. Aerosol concentrations returned to near background levels by Spring, 2010. After accounting for expected sources of discrepancy between each of the data sources, the magnitudes and spatial distributions of aerosol optical depth due to the eruption largely agree. In conducting the simulations, we likely overestimated both particle size and the amount of SO2 injected into the stratosphere, resulting in modeled optical depth values that were a factor of 2-4 too high. Model results of optical depth due to the eruption show a peak too late in high latitudes and too early in low latitudes, suggesting a problem with stratospheric circulation in the model. The model also shows a higher annual decay rate in optical depth than is observed, showing an inaccuracy in seasonal deposition rates. The modeled deposition rate of sulfate aerosols from the Sarychev eruption is higher than the rate calculated for aerosols from the 1991 eruption of Mt. Pinatubo

    Sensitivity of Stratospheric Geoengineering with Black Carbon to Aerosol Size and Altitude of Injection

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    Simulations of stratospheric geoengineering with black carbon (BC) aerosols using a general circulation model with fixed sea surface temperatures show that the climate effects strongly depend on aerosol size and altitude of injection. 1 Tg BC/a injected into the lower stratosphere would cause little surface cooling for large radii but a large amount of surface cooling for small radii and stratospheric warming of over 60 C. With the exception of small particles, increasing the altitude of injection increases surface cooling and stratospheric warming. Stratospheric warming causes global ozone loss by up to 50% in the small radius case. The Antarctic shows less ozone loss due to reduction of polar stratospheric clouds, but strong circumpolar winds would enhance the Arctic ozone hole. Using diesel fuel to produce the aerosols is likely prohibitively expensive and infeasible. Although studying an absorbing aerosol is a useful counterpart to previous studies involving sulfate aerosols, black carbon geoengineering likely carries too many risks to make it a viable option for deployment

    Comparing subjective and objective neighbourhood deprivation and their association with health over time among older adults in England

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    The importance of neighbourhood on individual health is widely documented. Less is known about the relative role of objective and subjective reports of neighbourhood conditions, how their effect on health changes as people age, and whether they moderate each other’s impact on health. This study uses the English Longitudinal Study of Ageing (ELSA) to determine whether older adults report worse self-rated health as they age, and whether this differs between objective and subjective measures of neighbourhood. ELSA data contain 53,988 person-years across six waves collected biannually between 2002 and 03 and 2012 and 13. Objective neighbourhood conditions are measured by the 2004 Index of Multiple Deprivation, and subjective neighbourhood conditions are captured by a summative neighbourhood dissatisfaction score. We find both objective and subjective neighbourhood composite scores independently predict poor health. There is no change over time in the probability of reporting poor health by baseline objective or subjective neighbourhood scores, suggesting neighbourhood effects do not compound as older adults age. There is no moderating effect of area dissatisfaction on the relationship between neighbourhood deprivation and health. The findings provide little support for causal neighbourhood effects operating in later life and indicate different causal pathways through which objective and subjective neighbourhood deprivation impact on health

    Opinion: The scientific and community-building roles of the Geoengineering Model Intercomparison Project (GeoMIP) – past, present, and future

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    The Geoengineering Model Intercomparison Project (GeoMIP) is a coordinating framework, started in 2010, that includes a series of standardized climate model experiments aimed at understanding the physical processes and projected impacts of solar geoengineering. Numerous experiments have been conducted, and numerous more have been proposed as “test-bed” experiments, spanning a variety of geoengineering techniques aimed at modifying the planetary radiation budget: stratospheric aerosol injection, marine cloud brightening, surface albedo modification, cirrus cloud thinning, and sunshade mirrors. To date, more than 100 studies have been published that used results from GeoMIP simulations. Here we provide a critical assessment of GeoMIP and its experiments. We discuss its successes and missed opportunities, for instance in terms of which experiments elicited more interest from the scientific community and which did not, and the potential reasons why that happened. We also discuss the knowledge that GeoMIP has contributed to the field of geoengineering research and climate science as a whole: what have we learned in terms of intermodel differences, robustness of the projected outcomes for specific geoengineering methods, and future areas of model development that would be necessary in the future? We also offer multiple examples of cases where GeoMIP experiments were fundamental for international assessments of climate change. Finally, we provide a series of recommendations, regarding both future experiments and more general activities, with the goal of continuously deepening our understanding of the effects of potential geoengineering approaches and reducing uncertainties in climate outcomes, important for assessing wider impacts on societies and ecosystems. In doing so, we refine the purpose of GeoMIP and outline a series of criteria whereby GeoMIP can best serve its participants, stakeholders, and the broader science community

    G6-1.5K-SAI: a new Geoengineering Model Intercomparison Project (GeoMIP) experiment integrating recent advances in solar radiation modification studies

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    The Geoengineering Model Intercomparison Project (GeoMIP) has proposed multiple model experiments during the phases 5 and 6 of the Climate Model Intercomparison Project (CMIP), with the latest set of model experiment proposed in 2015. With phase 7 of CMIP in preparation, and with multiple efforts ongoing to better explore the potential space of outcomes for different Solar Radiation Modification (SRM) both in terms of deployment strategies and scenarios and in terms of potential impacts, the GeoMIP community has identified the need to propose and conduct a new experiment that could serve as a bridge between past iterations and future CMIP7 experiments. Here we report the details of such a proposed experiment, named G6-1.5K-SAI, to be conducted with the current generation of scenarios and models from CMIP6, and clarify the reasoning behind many of the new choices introduced. Namely, compared to the CMIP6 GeoMIP scenario G6sulfur, here we decided on: 1) an intermediate emission scenario as baseline (the Shared Socioeconomic Pathway 2-4.5); 2) a start date set in the future that includes both considerations around the likelihood of exceeding 1.5 ºC above preindustrial and some considerations around a likely start date for an SRM implementation; 3) a deployment strategy for Stratospheric Aerosol Injection that does not inject in the tropical pipe in order to obtain a more latitudinally uniform aerosol distribution. We also offer more details over the preferred experiment length and number of ensemble members, and include potential options for second-tier experiments some modeling groups might want to run. The specifics of the proposed experiment will further allow for a more direct comparison between results obtained with CMIP6 models and those obtained with future scenarios for CMIP7

    Part II, Provider perspectives: should patients be activated to request evidence-based medicine? a qualitative study of the VA project to implement diuretics (VAPID)

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    <p>Abstract</p> <p>Background</p> <p>Hypertension guidelines recommend the use of thiazide diuretics as first-line therapy for uncomplicated hypertension, yet diuretics are under-prescribed, and hypertension is frequently inadequately treated. This qualitative evaluation of provider attitudes follows a randomized controlled trial of a patient activation strategy in which hypertensive patients received letters and incentives to discuss thiazides with their provider. The strategy prompted high discussion rates and enhanced thiazide-prescribing rates. Our objective was to interview providers to understand the effectiveness and acceptability of the intervention from their perspective, as well as the suitability of patient activation for more widespread guideline implementation.</p> <p>Methods</p> <p>Semi-structured phone interviews were conducted with 21 primary care providers. Interviews were transcribed verbatim and reviewed by the interviewer before being analyzed for content. Interviews were coded, and relevant themes and specific responses were identified, grouped, and compared.</p> <p>Results</p> <p>Of the 21 providers interviewed, 20 (95%) had a positive opinion of the intervention, and 18 of 20 (90%) thought the strategy was suitable for wider use. In explaining their opinions of the intervention, many providers discussed a positive effect on treatment, but they more often focused on the process of patient activation itself, describing how the intervention facilitated discussions by informing patients and making them more pro-active. Regarding effectiveness, providers suggested the intervention worked like a reminder, highlighted oversights, or changed their approach to hypertension management. Many providers also explained that the intervention 'aligned' patients' objectives with theirs, or made patients more likely to accept a change in medications. Negative aspects were mentioned infrequently, but concerns about the use of financial incentives were most common. Relevant barriers to initiating thiazide treatment included a hesitancy to switch medications if the patient was at or near goal blood pressure on a different anti-hypertensive.</p> <p>Conclusions</p> <p>Patient activation was acceptable to providers as a guideline implementation strategy, with considerable value placed on the activation process itself. By 'aligning' patients' objectives with those of their providers, this process also facilitated part of the effectiveness of the intervention. Patient activation shows promise for wider use as an implementation strategy, and should be tested in other areas of evidence-based medicine.</p> <p>Trial registration</p> <p>National Clinical Trial Registry number NCT00265538</p

    Is Fairness in the Eye of the Beholder? An Impartial Spectator Analysis of Justice

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    A popular sentiment is that fairness is inexorably subjective and incapable of being determined by objective standards. This study, on the other hand, seeks to establish evidence on unbiased justice and to propose and demonstrate a general approach for measuring impartial views empirically. Most normative justice theories associate impartiality with limited information and with consensus, i.e., a high level of agreement about what is right. In both the normative and positive literature, information is usually seen as the raw material for self-serving bias and disagreement. In contrast, this paper proposes a type of impartiality that is associated with a high level of information. The crucial distinction is the emphasis here on the views of impartial spectators, rather than implicated stakeholders. I describe the quasi-spectator method, i.e., an empirical means to approximate the views of impartial spectators that is based on a direct relationship between information and consensus, whereby consensus refers to the level of agreement among actual evaluators of real world situations. Results of surveys provide evidence on quasi-spectator views and support this approach as a means to elicit moral preferences. By establishing a relationship between consensus and impartiality, this paper seeks to help lay an empirical foundation for welfare analysis, social choice theory and practical policy applications
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