21 research outputs found

    The TropD software package (v1): standardized methods for calculating tropical-width diagnostics

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    Observational and modeling studies suggest that Earth's tropical belt has widened over the late 20th century and will continue to widen throughout the 21st century. Yet, estimates of tropical-width variations differ significantly across studies. This uncertainty, to an unknown degree, is partly due to the large variety of methods used in studies of the tropical width. Here, methods for eight commonly used metrics of the tropical width are implemented in the Tropical-width Diagnostics (TropD) code package in the MATLAB programming language. To consolidate the various methods, the operations used in each of the implemented methods are reduced to two basic calculations: finding the latitude of a zero crossing and finding the latitude of a maximum. A detailed description of the methods implemented in the code and of the code syntax is provided, followed by a method sensitivity analysis for each of the metrics. The analysis provides information on how to reduce the methodological component of the uncertainty associated with fundamental aspects of the calculations, such as monthly vs. seasonal averaging biases, grid dependence, sensitivity to noise, and sensitivity to threshold criteria

    Regional Widening of Tropical Overturning: Forced Change, Natural Variability, and Recent Trends

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    The width of the tropical Hadley circulation (HC) has garnered intense interest in recent decades, owing to the emerging evidence for its expansion in observations and models and to the anticipated impacts on surface climate in its descending branches. To better clarify the causes and impacts of tropical widening, this work generalizes the zonal mean HC to the regional level by defining meridional overturning cells (RC) using the horizontally divergent wind. The edges of the RC are more closely connected to surface hydroclimate than more traditional metrics of regional tropical width (such as the sea level pressure ridge) or even than the zonal mean HC. Simulations reveal a robust weakening of the RC in response to greenhouse gas increases, along with a widening of the RC in some regions. For example, simulated widening of the zonal mean HC in the Southern Hemisphere appears to arise in large part from regional overturning anomalies over the Eastern Pacific, where there is no clear RC. Unforced interannual variability in the position of the zonal mean HC edge is associated with a more general regional widening. These distinct regional signatures suggest that the RCs may be well suited for the attribution of observed circulation trends. The spatial pattern of regional meridional overturning trends in reanalyses corresponds more closely to the pattern associated with unforced interannual variability than to the pattern associated with CO2 forcing, suggesting a large contribution of natural variability to the recent observed tropical widening trends

    Mitochondrial DNA induces Foley catheter related bladder inflammation via Toll-like receptor 9 activation

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    Abstract Bladder instrumentation engages the innate immune system via neutrophil activation, promoting inflammation and pain. Elevated levels of mitochondrial DNA (mtDNA) have been associated with tissue damage and organ dysfunction. We hypothesized that local bladder trauma induced by a Foley catheter (FC) will result in mtDNA release, migration of neutrophils into the bladder lumen, and activation of the Toll-like receptor 9 (TLR9) and nuclear factor kappa B (NF-κB) pathway leading to bladder tissue damage. We randomized 10 swine into two groups receiving uncoated, or chloroquine/N-Acetylcysteine (CQ/NAC)-coated FCs. Urine samples were analyzed for mtDNA activation of TLR9/NF-κB as demonstrated by indicators of neutrophil adhesion, migration, and activation. We found that uncoated FCs resulted in a unique active neutrophil phenotype that correlated with bladder epithelial injury, neutrophilia, necrosis, mtDNA release, TLR9/NF-κB activation, transcription and secretion of pro-inflammatory cytokines, and enhanced respiratory burst. In our study we observed that the high levels of mtDNA and elevated TLR9/NF-κB activity were ameliorated in the CQ/NAC-coated FC group. These findings suggest that post-migrated bladder luminal neutrophils are involved in local tissue damage and amelioration of the mtDNA/TLR9/NF-κB inflammatory axis may represent a therapeutic target to prevent inflammation, and bladder tissue injury

    Design and Implementation of the Diabetes Impact Project: A Multisector Partnership to Reduce Diabetes Burden in Indianapolis Communities

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    Context: Community-level health disparities have not arisen suddenly but are the result of long-term systemic inequities. This article describes the design and implementation of a community-engaged multisector partnership to address health disparities by reducing the diabetes burden in 3 Indianapolis communities through the implementation of evidence-based strategies across the prevention continuum. Program: The project has 5 foundational design principles: engage partners from multiple sectors to address community health, focus on geographic communities most affected by the health disparity, practice authentic community engagement, commit for the long term, and utilize a holistic approach spanning the prevention continuum. Implementation: The design principles are incorporated into the following project components in each community: (1) health system community health workers (hCHWs), (2) neighborhood CHWs (nCHWs), (3) community health promotion initiatives, and (4) resident steering committees, as well as a backbone organization responsible for overall coordination, project communication, evaluation, and partnership coordination. Evaluation: This complex multilevel intervention is being evaluated using data sources and methodologies suited to each project component and its purpose overall. Each component is being evaluated independently and included holistically to measure the impact of the project on the health and culture of health in the communities. Key Performance Indicators were established upon project initiation as our common metrics for the partnership. Because complex interventions aiming at population-level change take time, we evaluate Diabetes Impact Project-Indianapolis Neighborhoods (DIP-IN), assuming its impact will take many years to achieve. Discussion: Health disparities such as the diabetes prevalence in project communities have not arisen suddenly but are the result of long-term systemic inequities. This complex issue requires a complex holistic solution with long-term commitment, trusted partnerships, and investment from diverse sectors as seen in this project. Implications for policy and practice include the need to identify stable funding mechanisms to support these types of holistic approaches

    Tropical widening: From global variations to regional impacts

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    Over the past 15 years, numerous studies have suggested that the sinking branches of Earth’s Hadley circulation and the associated subtropical dry zones have shifted poleward over the late twentieth century and early twenty-first century. Early estimates of this tropical widening from satellite observations and reanalyses varied from 0.25° to 3° latitude per decade, while estimates from global climate models show widening at the lower end of the observed range. In 2016, two working groups, the U.S. Climate Variability and Predictability (CLIVAR) working group on the Changing Width of the Tropical Belt and the International Space Science Institute (ISSI) Tropical Width Diagnostics Intercomparison Project, were formed to synthesize current understanding of the magnitude, causes, and impacts of the recent tropical widening evident in observations. These working groups concluded that the large rates of observed tropical widening noted by earlier studies resulted from their use of metrics that poorly capture changes in the Hadley circulation, or from the use of reanalyses that contained spurious trends. Accounting for these issues reduces the range of observed expansion rates to 0.25°–0.5° latitude decade‒1^{‒1}—within the range from model simulations. Models indicate that most of the recent Northern Hemisphere tropical widening is consistent with natural variability, whereas increasing greenhouse gases and decreasing stratospheric ozone likely played an important role in Southern Hemisphere widening. Whatever the cause or rate of expansion, understanding the regional impacts of tropical widening requires additional work, as different forcings can produce different regional patterns of widening
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