Peat decomposition records in three pristine ombrotrophic bogs in southern Patagonia

Ombrotrophic bogs in southern Patagonia have been examined with regard to paleoclimatic and geochemical research questions but knowledge about organic matter decomposition in these bogs is limited. Therefore, we examined peat humification with depth by Fourier Transformed Infrared (FTIR) measurements of solid peat, C/N ratio, and δ<sup>13</sup>C and δ<sup>15</sup>N isotope measurements in three bog sites. Peat decomposition generally increased with depth but distinct small scale variation occurred, reflecting fluctuations in factors controlling decomposition. C/N ratios varied mostly between 40 and 120 and were significantly correlated (<i>R</i><sup>2</sup> > 0.55, <i>p</i> < 0.01) with FTIR-derived humification indices. The degree of decomposition was lowest at a site presently dominated by <i>Sphagnum</i> mosses. The peat was most strongly decomposed at the driest site, where currently peat-forming vegetation produced less refractory organic material, possibly due to fertilizing effects of high sea spray deposition. Decomposition of peat was also advanced near ash layers, suggesting a stimulation of decomposition by ash deposition. Values of δ<sup>13</sup>C were 26.5 ± 2‰ in the peat and partly related to decomposition indices, while δ<sup>15</sup>N in the peat varied around zero and did not consistently relate to any decomposition index. Concentrations of DOM partly related to C/N ratios, partly to FTIR derived indices. They were not conclusively linked to the decomposition degree of the peat. DOM was enriched in <sup>13</sup>C and in <sup>15</sup>N relative to the solid phase probably due to multiple microbial modifications and recycling of N in these N-poor environments. In summary, the depth profiles of C/N ratios, δ<sup>13</sup>C values, and FTIR spectra seemed to reflect changes in environmental conditions affecting decomposition, such as bog wetness, but were dominated by site specific factors, and are further influenced by ash deposition and possibly by sea spray input

Iodine speciation in rain, snow and aerosols and possible transfer of organically bound iodine species from aerosol to droplet phases

International audienceIodine oxides, such as iodate, should theoretically be the only stable sink species for iodine in the troposphere. However, field observations have increasingly found very little iodate and significant amounts of iodide and organically bound iodine in precipitation and aerosols. The aim of this study was to investigate iodine speciation, including the organic fraction, in rain, snow, and aerosols in an attempt to further clarify aqueous phase iodine chemistry. Diurnal aerosol samples were taken with a 5 stage cascade impactor and a virtual impactor (PM2.5) from the Mace Head research station, Ireland, during summer 2006. Rain was collected from Australia, New Zealand, Patagonia, Germany, Ireland, and Switzerland while snow was obtained from Greenland, Germany, Switzerland, and New Zealand. All samples were analysed for total iodine by inductively coupled plasma mass spectrometry (ICP-MS) and speciation was determined by coupling an ion chromatography unit to the ICP-MS. Total iodine in the aerosols from Mace Head gave a median concentration of 50 pmol m?3 of which the majority was associated with the organic fraction (median day: 91±7%, night: 94±6% of total iodine). Iodide exhibited higher concentrations than iodate (median 5% vs. 0.8% of total iodine), and displayed significant enrichment during the day compared to the night. Interestingly, up to 5 additional, presumably anionic organic peaks were observed in all IC-ICP-MS chromatograms, composing up to 15% of the total iodine. Organically bound iodine was also the dominant fraction in all rain and snow samples, with lesser amounts of iodide and iodate (iodate was particularly low in snow). Two of the same unidentified peaks found in aerosols were also observed in precipitation from both Southern and Northern Hemispheres, suggesting that these species are transferred from the aerosol phase into precipitation. It is suggested that organo-I is formed by reactions between HOI and organic matter derived from the ocean surface layer. This may then photolytically decompose to give iodide and the unidentified species. The data in this study show that iodine oxides are the least abundant species in rain, snow, and aerosols and therefore considerably more effort is required on aqueous phase iodine chemistry for a holistic understanding of the iodine cycle

Long-term trends at the Time Series Station Boknis Eck (Baltic Sea), 1957–2013: does climate change counteract the decline in eutrophication?

The Boknis Eck (BE) time series station, initiated in 1957, is one of the longest-operated time series stations worldwide. We present the first statistical evaluation of a data set of nine physical, chemical and biological parameters in the period of 1957–2013. In the past three to five decades, all of the measured parameters underwent significant long-term changes. Most striking is an ongoing decline in bottom water oxygen concentration, despite a significant decrease of nutrient and chlorophyll a concentrations. Temperature-enhanced oxygen consumption in the bottom water and a prolongation of the stratification period are discussed as possible reasons for the ongoing oxygen decline despite declining eutrophication. Observations at the BE station were compared with model output of the Kiel Baltic Sea Ice Ocean Model (BSIOM). Reproduced trends were in good agreement with observed trends for temperature and oxygen, but generally the oxygen concentration at the bottom has been overestimated

Understanding the Operative Experience of the Practicing Pediatric Surgeon: Implications for Training and Maintaining Competency

Importance The number of practicing pediatric surgeons has increased rapidly in the past 4 decades, without a significant increase in the incidence of rare diseases specific to the field. Maintenance of competency in the index procedures for these rare diseases is essential to the future of the profession. Objective To describe the demographic characteristics and operative experiences of practicing pediatric surgeons using Pediatric Surgery Board recertification case log data. Design, Setting, and Participants We performed a retrospective review of 5 years of pediatric surgery certification renewal applications submitted to the Pediatric Surgery Board between 2009 and 2013. A surgeon’s location was defined by population as urban, large rural, small rural, or isolated. Case log data were examined to determine case volume by category and type of procedures. Surgeons were categorized according to recertification at 10, 20, or 30 years. Main Outcome and Measure Number of index cases during the preceding year. Results Of 308 recertifying pediatric surgeons, 249 (80.8%) were men, and 143 (46.4%) were 46 to 55 years of age. Most of the pediatric surgeons (304 of 308 [98.7%]) practiced in urban areas (ie, with a population >50 000 people). All recertifying applicants were clinically active. An appendectomy was the most commonly performed procedure (with a mean [SD] number of 49.3 [35.0] procedures per year), nonoperative trauma management came in second (with 20.0 [33.0] procedures per year), and inguinal hernia repair for children younger than 6 months of age came in third (with 14.7 [13.8] procedures per year). In 6 of 10 “rare” pediatric surgery cases, the mean number of procedures was less than 2. Of 308 surgeons, 193 (62.7%) had performed a neuroblastoma resection, 170 (55.2%) a kidney tumor resection, and 123 (39.9%) an operation to treat biliary atresia or choledochal cyst in the preceding year. Laparoscopy was more frequently performed in the 10-year recertification group for Nissen fundoplication, appendectomy, splenectomy, gastrostomy/jejunostomy, orchidopexy, and cholecystectomy (P < .05) but not lung resection (P = .70). It was more frequently used by surgeons recertifying in the 10-year group (used in 11 375 of 14 456 procedures [78.7%]) than by surgeons recertifying in the 20-year (used in 6214 of 8712 procedures [71.3%]) or 30-year group (used in 2022 of 3805 procedures [53.1%]). Conclusions and Relevance Practicing pediatric surgeons receive limited exposure to index cases after training. With regard to maintaining competency in an era in which health care outcomes have become increasingly important, these results are concerning

In Vitro Studies Evaluating Leaching of Mercury from Mine Waste Calcine Using Simulated Human Body Fluids

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almadén, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 μg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 μg of Hg leached/g), serum-based fluid (as much as 1600 μg of Hg leached/g), and water of pH 5 (as much as 880 μg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway

Statistical Multiplicity in Systematic Reviews of Anaesthesia Interventions: A Quantification and Comparison between Cochrane and Non-Cochrane Reviews

BACKGROUND: Systematic reviews with meta-analyses often contain many statistical tests. This multiplicity may increase the risk of type I error. Few attempts have been made to address the problem of statistical multiplicity in systematic reviews. Before the implications are properly considered, the size of the issue deserves clarification. Because of the emphasis on bias evaluation and because of the editorial processes involved, Cochrane reviews may contain more multiplicity than their non-Cochrane counterparts. This study measured the quantity of statistical multiplicity present in a population of systematic reviews and aimed to assess whether this quantity is different in Cochrane and non-Cochrane reviews. METHODS/PRINCIPAL FINDINGS: We selected all the systematic reviews published by the Cochrane Anaesthesia Review Group containing a meta-analysis and matched them with comparable non-Cochrane reviews. We counted the number of statistical tests done in each systematic review. The median number of tests overall was 10 (interquartile range (IQR) 6 to 18). The median was 12 in Cochrane and 8 in non-Cochrane reviews (difference in medians 4 (95% confidence interval (CI) 2.0-19.0). The proportion that used an assessment of risk of bias as a reason for doing extra analyses was 42% in Cochrane and 28% in non-Cochrane reviews (difference in proportions 14% (95% CI -8 to 36). The issue of multiplicity was addressed in 6% of all the reviews. CONCLUSION/SIGNIFICANCE: Statistical multiplicity in systematic reviews requires attention. We found more multiplicity in Cochrane reviews than in non-Cochrane reviews. Many of the reasons for the increase in multiplicity may well represent improved methodological approaches and greater transparency, but multiplicity may also cause an increased risk of spurious conclusions. Few systematic reviews, whether Cochrane or non-Cochrane, address the issue of multiplicity

Effect of predicted low suspend pump treatment on improving glycaemic control and quality of sleep in children with type 1 diabetes and their caregivers: the QUEST randomized crossover study.

BACKGROUND: In attempting to achieve optimal metabolic control, the day-to-day management is challenging for a child with type 1 diabetes (T1D) and his family and can have a major negative impact on their quality of life. Augmenting an insulin pump with glucose sensor information leads to improved outcomes: decreased haemoglobin A1c levels, increased time in glucose target and less hypoglycaemia. Fear of nocturnal hypoglycaemia remains pervasive amongst parents, leading to chronic sleep interruption and lack of sleep for the parents and their children. The QUEST study, an open-label, single-centre randomized crossover study, aims to evaluate the impact on time in target, in hypoglycaemia and hyperglycaemia and the effect on sleep and quality of life in children with T1D, comparing a sensor-augmented pump (SAP) with predictive low glucose suspend and alerts to the use of the same insulin pump with a flash glucose measurement (FGM) device not interacting with the pump. METHODS/DESIGN: Subjects meeting the inclusion criteria are randomized to treatment with the SAP or treatment with an insulin pump and independent FGM for 5 weeks. Following a 3-week washout period, the subjects cross over to the other study arm for 5 weeks. During the week before and in the last week of treatment, the subjects and one of their caregivers wear a sleep monitor in order to obtain sleep data. The primary endpoint is the between-arm difference in percentage of time in glucose target during the final 6 days of each treatment arm, measured by a blinded continuous glucose measurement (CGM). Additional endpoints include comparison of quantity and quality of sleep as well as quality of life perception of the subjects and one of their caregivers in the two different treatment arms. Recruitment started in February 2017. A total of 36 patients are planned to be randomized. The study recruitment was completed in April 2018. DISCUSSION: With this study we will provide more information on whether insulin pump treatment combined with more technology (SmartGuard® feature and alerts) leads to better metabolic control. The inclusion of indicators on quality of sleep with less sleep interruption, less lack of sleep and perception of quality of life in both children and their primary caregivers is essential for this study and might help to guide us to further treatment improvement. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03103867 . Registered on 6 April 2017

Isotopic Variability of Mercury in Ore, Mine-Waste Calcine, and Leachates of Mine-Waste Calcine from Areas Mined for Mercury

The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that δ202Hg values relative to NIST 3133 of calcine (up to 1.52‰) in the Terlingua district, Texas, are as much as 3.24‰ heavier than cinnabar (−1.72‰) prior to retorting. In addition, δ202Hg values obtained from leachates of Terlingua district calcines are isotopically similar to, or as much as 1.17‰ heavier than associated calcines, most likely due to leaching of soluble, byproduct Hg compounds formed during ore retorting that are a minor component in the calcines. As a result of the large fractionation found between cinnabar and calcine, and because calcine is the dominant source of Hg contamination from the mines studied, δ202Hg values of calcine may be more environmentally important in these mined areas than the primary cinnabar ore. Measurement of the Hg isotopic composition of calcine is necessary when using Hg isotopes for tracing Hg sources from areas mined for Hg, especially mine water runoff

Clinical targets for continuous glucose monitoring data interpretation : recommendations from the international consensus on time in range

Improvements in sensor accuracy, greater convenience and ease of use, and expanding reimbursement have led to growing adoption of continuous glucose monitoring (CGM). However, successful utilization of CGM technology in routine clinical practice remains relatively low. This may be due in part to the lack of clear and agreed-upon glycemic targets that both diabetes teams and people with diabetes can work toward. Although unified recommendations for use of key CGM metrics have been established in three separate peer-reviewed articles, formal adoption by diabetes professional organizations and guidance in the practical application of these metrics in clinical practice have been lacking. In February 2019, the Advanced Technologies & Treatments for Diabetes (ATTD) Congress convened an international panel of physicians, researchers, and individuals with diabetes who are expert in CGM technologies to address this issue. This article summarizes the ATTD consensus recommendations for relevant aspects of CGM data utilization and reporting among the various diabetes populations