9 research outputs found

    Cariaco Basin calibration update; revisions to calendar and 14C chronologies for core PL07-58PC

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    Author Posting. © Arizona Board of Regents on behalf of the University of Arizona, 2004. This article is posted here by permission of Dept. of Geosciences, University of Arizona for personal use, not for redistribution. The definitive version was published in Radiocarbon 46 (2004): 1161-1187.This paper describes the methods used to develop the Cariaco Basin PL07-58PC marine radiocarbon calibration data set. Background measurements are provided for the period when Cariaco samples were run, as well as revisions leading to the most recent version of the floating varve chronology. The floating Cariaco chronology has been anchored to an updated and expanded Preboreal pine tree-ring data set, with better estimates of uncertainty in the wiggle-match. Pending any further changes to the dendrochronology, these results represent the final Cariaco 58PC calibration data set.This work was supported by LLNL (97-ERI-009), DOE (W-7405-Eng-48), and NSF (ATM- 9709563)

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Carbon Transfer from Labeled Leaf Litter into Mineral Soil at the University of Missouri Baskett Research Area, a Deciduous Forest in the Eastern United States

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    We used radiocarbon enriched leaf litter to quantify the transfer of carbon through a soil profile at an eastern deciduous forest in the United States, located at the University of Missouri\u27s Baskett research area in the Ozark mountains. Mineral soil was sampled from five plots before (2007) and after (2008 and 2009). Radiocarbon enriched leaf litter was applied to the soil surface each year and samples of native litter-fall and mineral soil from 0-5 cm, 5-15 cm, and 15-30 cm depths were collected. Soil samples were first put through a 2mm sieve and the particles that passed through the sieve were dried at 70 degrees Celsius for several days until constant mass was reached. The samples were then sent to Lawrence Livermore National Laboratory to be graphitized and subsequently run on the accelerator mass spectrometer. The method for graphitizing the samples was to measure out an amount of soil based on its estimated percent carbon concentration that would yield 1mg of graphite for analysis. The first process was to combust the soil with copper oxide and silver catalyst under vacuum. The gases produced by combustion were put on a graphitization rig and the water vapor and other incondensibles were separated from the carbon dioxide based on each gases physical properties. The carbon dioxide was ultimately separated and sent to a reaction chamber where it was reduced in the presence of hydrogen gas and an iron catalyst that provided a surface for the graphite to adhere to during the reduction reaction. The iron also served as a binder and thermal conductor. The graphite was then pounded into targets and analyzed on the accelerator mass spectrometer. Measurements of the carbon-14 count to carbon-13 current were taken. This information was then used in the mixing model equation to calculate the fraction of carbon in the mineral soil that was transferred from the radiocarbon enriched leaf litter on the surface. The results show that 8% of the carbon from the labeled leaf litter transferred down to the 0-5cm mineral soil depth. The 0-5cm depth was the only depth that showed a statistically significant increase in radiocarbon after 2 years. t-tests also showed the mean differences in radiocarbon in the 2007 versus 2009 5-15cm and 15-30 cm respective depths did not have enough evidence to support a claim at a 25% level of certainty of an increase in radiocarbon. To determine whether there was an increase in radiocarbon with statistical certainty at these depths over time we would need more replicates and/or more time for the transfer to occur before the next sample is taken

    Anomalous elevated radiocarbon measurements of PM2.5

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    Two-component models are often used to determine the contributions made by fossil fuel and natural sources of carbon in airborne particulate matter (PM). The models reduce thousands of actual sources to two end members based on isotopic signature. Combustion of fossil fuels produces PM free of carbon-14 (14C). Wood or charcoal smoke, restaurant fryer emissions, and natural emissions from plants produce PM with the contemporary concentration of 14C approximately 1.2 × 10-1214C/C. Such data can be used to estimate the relative contributions of fossil fuels and biogenic aerosols to the total aerosol loading and radiocarbon analysis is becoming a popular source apportionment method. Emissions from incinerators combusting medical or biological wastes containing tracer 14C can skew the 14C/C ratio of PM, however, so critical analysis of sampling sites for possible sources of elevated PM needs to be completed prior to embarking on sampling campaigns. Results are presented for two ambient monitoring sites in different areas of the United States where 14C contamination is apparent. Our experience suggests that such contamination is uncommon but is also not rare (∼10%) for PM sampling sites

    Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study (Intensive Care Medicine, (2021), 47, 2, (160-169), 10.1007/s00134-020-06234-9)

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    The original version of this article unfortunately contained a mistake. The members of the ESICM Trials Group Collaborators were not shown in the article but only in the ESM. The full list of collaborators is shown below. The original article has been corrected
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