1,147 research outputs found

    The Thermal Properties of Solar Flares Over Three Solar Cycles Using GOES X-ray Observations

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    Solar flare X-ray emission results from rapidly increasing temperatures and emission measures in flaring active region loops. To date, observations from the X-Ray Sensor (XRS) onboard the Geostationary Operational Environmental Satellite (GOES) have been used to derive these properties, but have been limited by a number of factors, including the lack of a consistent background subtraction method capable of being automatically applied to large numbers of flares. In this paper, we describe an automated temperature and emission measure-based background subtraction method (TEBBS), which builds on the methods of Bornmann (1990). Our algorithm ensures that the derived temperature is always greater than the instrumental limit and the pre-flare background temperature, and that the temperature and emission measure are increasing during the flare rise phase. Additionally, TEBBS utilizes the improved estimates of GOES temperatures and emission measures from White et al. (2005). TEBBS was successfully applied to over 50,000 solar flares occurring over nearly three solar cycles (1980-2007), and used to create an extensive catalog of the solar flare thermal properties. We confirm that the peak emission measure and total radiative losses scale with background subtracted GOES X-ray flux as power-laws, while the peak temperature scales logarithmically. As expected, the peak emission measure shows an increasing trend with peak temperature, although the total radiative losses do not. While these results are comparable to previous studies, we find that flares of a given GOES class have lower peak temperatures and higher peak emission measures than previously reported. The resulting TEBBS database of thermal flare plasma properties is publicly available on Solar Monitor (www.solarmonitor.org/TEBBS/) and will be available on Heliophysics Integrated Observatory (www.helio-vo.eu)

    A Qualitative Study on Pharmacy Policies toward Over-the-Counter Syringe Sales in a Rural Epicenter of US Drug-Related Epidemics

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    BACKGROUND: Expanding access to sterile syringes in rural areas is vital, as injection-related epidemics expand beyond metropolitan areas globally. While pharmacies have potential to be an easily accessible source of sterile syringes, research in cities has identified moral, legal and ethical barriers that preclude over-the-counter (OTC) sales to people who inject drugs (PWID). The current study builds on prior urban-based research by elucidating (1) pharmacy OTC policies and (2) pharmacists\u27 rationale for, and barriers and facilitators to, OTC syringe sales in a US rural area hard hit by drug-related epidemics. METHODS: We conducted 14 semi-structured interviews with pharmacists recruited from two Eastern Kentucky health districts. Interview domains included experiences with, and attitudes toward, selling OTC syringes to PWID. Constructivist grounded theory methods were used to analyze verbatim transcripts. RESULTS: Most pharmacists operated restrictive OTC pharmacies (n = 8), where patients were required to have a prescription or proof of medical need to purchase a syringe. The remainder (n = 6) operated open OTC pharmacies, which allowed OTC syringe sales to most patients. Both groups believed their pharmacy policies protected their community and pharmacy from further drug-related harm, but diverging policies emerged because of stigma toward PWID, perceptions of Kentucky law, and belief OTC syringe sales were harmful rather than protective to the community. CONCLUSION: Our results suggest that restrictive OTC pharmacy policies are rooted in stigmatizing views of PWID. Anti-stigma education about substance use disorder (SUD), human immunodeficiency virus (HIV), and Hepatitis C (HCV) is likely needed to truly shift restrictive pharmacy policy

    Regular exercise during haemodialysis promotes an anti-inflammatory leucocyte profile

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    Background Cardiovascular disease (CVD) is the most common cause of mortality in haemodialysis (HD) patients and is highly predicted by markers of chronic inflammation. Regular exercise may have beneficial anti-inflammatory effects, but this is unclear in HD patients. This study assessed the effect of regular intradialytic exercise on soluble inflammatory factors and inflammatory leukocyte phenotypes. Methods Twenty-two HD patients from a centre where intradialytic cycling was offered thrice-weekly and 16 HD patients receiving usual care volunteered. Exercising patients aimed to cycle for 30 min at RPE of “somewhat hard”. Baseline characteristic were compared with 16 healthy age-matched individuals. Physical function, soluble inflammatory markers and leukocyte phenotypes were assessed again after 6 months of regular exercise. Results Patients were less active than their healthy counterparts and had significant elevations in measures of inflammation (IL-6, CRP, TNF-α, intermediate and non-classical monocytes; all P<0.001). Six months of regular intradialytic exercise improved physical function (sit-to-stand 60). After 6 months the proportion of intermediate monocytes in the exercising patients reduced compared to non-exercisers (7.58±1.68 to 6.38±1.81% vs. 6.86±1.45 to 7.88±1.66%; P<0.01). Numbers (but not proportion) of regulatory T cells decreased in the non-exercising patients only (P<0.05). Training had no significant effect on circulating IL-6, CRP or TNF-α concentrations. Conclusions These findings suggest regular intradialytic exercise is associated with an anti-inflammatory effect at a circulating cellular level but not in circulating cytokines. This may be protective against the increased risk of CVD and mortality that is associated with chronic inflammation and elevated numbers of intermediate monocytes

    DNA hypomethylation during MSC chondrogenesis occurs predominantly at enhancer regions

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    Regulation of transcription occurs in a cell type specific manner orchestrated by epigenetic mechanisms including DNA methylation. Methylation changes may also play a key role in lineage specification during stem cell differentiation. To further our understanding of epigenetic regulation in chondrocytes we characterised the DNA methylation changes during chondrogenesis of mesenchymal stem cells (MSCs) by Infinium 450 K methylation array. Significant DNA hypomethylation was identified during chondrogenic differentiation including changes at many key cartilage gene loci. Integration with chondrogenesis gene expression data revealed an enrichment of significant CpGs in upregulated genes, while characterisation of significant CpG loci indicated their predominant localisation to enhancer regions. Comparison with methylation profiles of other tissues, including healthy and diseased adult cartilage, identified chondrocyte-specific regions of hypomethylation and the overlap with differentially methylated CpGs in osteoarthritis. Taken together we have associated DNA methylation levels with the chondrocyte phenotype. The consequences of which has potential to improve cartilage generation for tissue engineering purposes and also to provide context for observed methylation changes in cartilage diseases such as osteoarthritis

    Repeat bleaching of a central Pacific coral reef over the past six decades (1960–2016)

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    © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Communications Biology 1 (2018): 177, doi:10.1038/s42003-018-0183-7.The oceans are warming and coral reefs are bleaching with increased frequency and severity, fueling concerns for their survival through this century. Yet in the central equatorial Pacific, some of the world’s most productive reefs regularly experience extreme heat associated with El Niño. Here we use skeletal signatures preserved in long-lived corals on Jarvis Island to evaluate the coral community response to multiple successive heatwaves since 1960. By tracking skeletal stress band formation through the 2015-16 El Nino, which killed 95% of Jarvis corals, we validate their utility as proxies of bleaching severity and show that 2015-16 was not the first catastrophic bleaching event on Jarvis. Since 1960, eight severe (>30% bleaching) and two moderate (<30% bleaching) events occurred, each coinciding with El Niño. While the frequency and severity of bleaching on Jarvis did not increase over this time period, 2015–16 was unprecedented in magnitude. The trajectory of recovery of this historically resilient ecosystem will provide critical insights into the potential for coral reef resilience in a warming world.Funding for this study was provided by National Science Foundation awards OCE 1537338, OCE 1605365, and OCE 1031971 to A.L.C., and the Robertson Foundation to A.L.C., National Science Foundation Graduate Research Fellowships to T.M.D. and A.E.A., and a National Defense Science and Engineering Graduate Fellowship to H.E.R
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