233 research outputs found

    Depositional Environments and Petrology of the Felix Coal Interval (Eocene), Powder River Basin, Wyoming

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    A study of a 250 ft. (76.2 m) stratigraphic interval that includes the Eocene-age Felix coal of the Wasatch Formation was undertaken in the Powder River Basin of Wyoming to establish a depositional model based on the interrelations of coal-seam geometry, coal maceral composition, and spatial distribution of adjoining rocks. Regional cross sections and maps of major rock bodies were prepared from 147 measured stratigraphic sections and 56 geophysical logs. Trends in maceral and chemical properties within the Felix coal were identified from petrographic and geochemical analyses of 72 coal channel samples. The combined data sets indicate that the thickest portions of the coal are underlain by widespread, interconnected, sandstone-dominated fining-upward sequences (\u3c 50 ft. or 15 m thick over a 300 sq. mi. or 777 sq. km area) whereas areas of thin or split coal are underlain by stacked predominantly fine grained, coarsening-upward sequences (\u3c 50 ft. or 15 m thick). Above the coal, fining-upward sequences are concentrated over thin coal areas and widespread (\u3e 20 mi., 32 km wide) coarsening-upward sequences overlie thick coal areas. Megascopic and petrographic description of the coal indicates that the brightest coal contains the greatest amount of huminite. This type coal occurs in the lowest portion of the seam and directly above clay partings in thick coal areas and in split benches · on the margin of the deposit. The central and upper portion of the seam is predominantly dull, and inertinite percentages increase towards the top of the seam. The deposits below the Felix resulted from north-northwest flowing meandering rivers. Thick peat represented by thick portions of the Felix coal accumulated upon this sandstone-dominated, poorly compactible platform that was free of sediment influx. Areas of thin and split Felix coal, underlain by fine-grained, more-compactible sediments, attracted water-borne elastics that interrupted peat accumulation. The base and split portions of the seam are the remains of predominantly coniferous trees that grew within a nutrient-rich environment, and the duller central and upper portions of the seam indicate oxidation associated with a raised peat deposit. Ash falls and fires during late stages of peat accumulation may have contributed to the demise of the swamp. After vegetation died large lakes formed and were subsequently filled by crevasse deposits from streams. The final phase of compaction of the fine-grained lake sediments and the thick underlying peat attracted anastomosed alluvial channels

    Sorption of selected radionuclides to clay in the presence of humic acid

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    Within the framework of the FUNMIG programme, Loughborough University is performing work to increase understanding of the sorption behaviour of selected radionuclides with various minerals in the absence and presence of competing complexing ligands, such as humic acid (HA). The determination of the distribution ratios (Rd) of binary (metal- and humic-solid), and ternary (metal-solid-humic) systems using a batch adsorption technique is reported. Four radionuclides have been used; 137Cs, 63Ni, 152Eu and 109Cd, to facilitate modelling. Montmorillonite, kaolinite and α-goethite have been used as solids. Humic acid concentrations (2 - 300 ppm (w/v)) were determined using UV spectrophotometry. Radiometric analysis was used for radionuclide measurement. Construction of sorption isotherms using the Langmuir and Freundlich Equations has allowed characterisation of sorption types, and has provided maximum sorption capacities of the solid surfaces for each of the metals in the binary systems. Distribution relationships between metal and humic acid for each ternary system have been established and correlated

    Pole-to-Pole Connections : Similarities between Arctic and Antarctic Microbiomes and Their Vulnerability to Environmental Change

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    Acknowledgments JK acknowledges the Carl Zeiss foundation for PhD funding, the Marie-Curie COFUND-BEIPD PostDoc fellowship for PostDoc funding, FNRS travel funding and the logistical and financial support by UNIS. JK and FK acknowledge the Natural Environment Research Council (NERC) Antarctic Funding Initiative AFI-CGS-70 (collaborative gearing scheme) and logistic support from the British Antarctic Survey (BAS) for field work in Antarctica. JK and CZ acknowledge the Excellence Initiative at the University of Tübingen funded by the German Federal Ministry of Education and Research and the German Research Foundation (DFG). FH, AV, and PB received funding from MetaHIT (HEALTH-F4-2007-201052), Microbios (ERC-AdG-502 669830) and the European Molecular Biology Laboratory (EMBL). We thank members of the Bork group at EMBL for helpful discussions. We acknowledge the EMBL Genomics Core Facility for sequencing support and Y. P. Yuan and the EMBL Information Technology Core Facility for support with high-performance computing and EMBL for financial support. PC is supported by NERC core funding to the BAS “Biodiversity, Evolution and Adaptation” Team. MB was funded by Helge Ax:son Johnsons Stiftelse and PUT1317. DRD acknowledges the DFG funded project DI698/18-1 Dietrich and the Marie Curie International Research Staff Exchange Scheme Fellowship (PIRSES-GA-2011-295223). Operations in the Canadian High Arctic were supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), ArcticNet and the Polar Continental Shelf Program (PCSP). We are also grateful to the TOTAL Foundation (Paris) and the UK NERC (WP 4.3 of Oceans 2025 core funding to FCK at the Scottish Association for Marine Science) for funding the expedition to Baffin Island and within this context Olivier Dargent and Dr. Pieter van West for sample collection, and the Spanish Ministry of Science and Technology through project LIMNOPOLAR (POL200606635 and CGL2005-06549-C02-01/ANT to AQ as well as CGL2005-06549-C02-02/ANT to AC, the last of these co-financed by European FEDER funds). We are grateful for funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland), funded by the Scottish Funding Council (HR09011) and contributing institutions. Supplementary Material The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fevo.2017.00137/full#supplementary-materialPeer reviewedPublisher PD

    A procedure to assess the importance of chemical kinetics in the humic-mediated transport of radionuclides in radiological performance assessment calculations

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    Previous work has shown that humic substances can bind metal ions in two fractions: the exchangeable, where it is available instantaneously for reaction with other sinks (such as mineral surfaces); and the non-exchangeable, from which it may only dissociate slowly. In the absence of metal ion/humic/mineral surface ternary complexes, if the dissociation rate is slow compared to the solution residence time in the groundwater column, then metal in the non-exchangeable will have a significantly higher mobility than that in the exchangeable. The critical factor is the ratio of the non-exchangeable first order dissociation rate constant and the residence time in the groundwater column, metal ion mobility increasing with decreasing rate constant. Sorption of humic/metal complexes at mineral surfaces may reduce mobility. In addition to direct retardation, sorption also increases the residence time of the non-exchangeable fraction, giving more time for dissociation and immobilisation. The magnitude of the effect depends upon the concentrations of the mineral surface humic binding sites and the humic in solution, along with the magnitudes of the equilibrium constant and the forward and backward rate constants. The non-exchangeable dissociation reaction and the sorption reaction may be classified in terms of two Damkohler numbers, which can be used to determine the importance of chemical kinetics during transport calculations. These numbers could be used to determine when full chemical kinetic calculations are required for a reliable prediction, and when equilibrium may be assumed, or when the reactions are sufficiently slow that they may be ignored completely

    The role of humic non-exchangeable binding in the promotion of metal ion

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    Metal ions form strong complexes with humic substances. When the metal ion is first complexed by humic material, it is bound in an ‘exchangeable’ mode. The metal ion in this fraction is strongly bound, however, if the metal–humic complex encounters a stronger binding site on a surface, then the metal ion may dissociate from the humic substance and be immobilised. However, over time, exchangeably-bound metal may transfer to a ‘non-exchangeable’ mode. Transfer into this mode and dissociation from it are slow, regardless of the strength of the competing sink, and so immobilisation may be hindered. A series of coupled chemical transport calculations has been performed to investigate the likely effects of non-exchangeable binding upon the transport of metal ions in the environment. The calculations show that metal in the nonexchangeable mode will have a significantly higher mobility than that in the exchangeable mode. The critical factor is the ratio of the non-exchangeable first-order dissociation rate constant and the residence time in the groundwater column, metal ion mobility increasing with decreasing rate constant. A second series of calculations has investigated the effect of the sorption to surfaces of humic/metal complexes on the transport of the non-exchangeably bound metal. It was found that such sorption may reduce mobility, depending upon the humic fraction to which the metal ion is bound. For the more weakly sorbing humic fractions, under ambient conditions (humic concentration etc.) the non-exchangeable fraction may still transport significantly. However, for the more strongly sorbed fractions, the non-exchangeable fraction has little effect upon mobility. In addition to direct retardation, sorption also increases the residence time of the nonexchangeable fraction, giving more time for dissociation and immobilisation. The nonexchangeable dissociation reaction, and the sorption reaction have been classified in terms of two Damkohler numbers, which can be used to determine the importance of chemical kinetics during transport calculations. These numbers have been used to develop a set of rules that determine when full chemical kinetic calculations are required for a reliable prediction, and when equilibrium may be assumed, or when the reactions are sufficiently slow that they may be ignored completely

    Sodium bicarbonate to improve physical function in patients over 60 years with advanced chronic kidney disease:the BiCARB RCT

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    Acknowledgements: We would like to acknowledge the support received from the NHS Scotland Support for Science scheme and the NIHR Renal and Ageing Comprehensive Research Networks; the work of all the investigators, research nurses and study teams at the different sites and the Tayside CTU staff; and, most importantly, all those with kidney disease who participated in the trial. In addition, we acknowledge the support and advice that we received from the independent TSC members (Professor David Stott, Professor Patrick Mark, Professor Tahir Masud and Mr Alex Stephen) and the independent DMC members (Professor Alex McConnachie, Professor David Wheeler, Dr Nicosha de Souza and Dr Andrew Clegg). Professor Marion McMurdo and Dr Simon Ogston were co-applicants on the original proposal, but demitted from the project on retirement and were not involved in the creation of this report. Trial registration: Current Controlled Trials ISRCTN09486651 and EudraCT 2011-005271-16. The systematic review is registered as PROSPERO CRD42018112908. Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 27. See the NIHR Journals Library website for further project information.Peer reviewedPublisher PD

    Tourniquet use for knee replacement surgery

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    Background Many surgeons prefer to perform total knee replacement surgery with the aid of a tourniquet. A tourniquet is an occlusive device that restricts distal blood flow to help create a bloodless field during the procedure. A tourniquet may be associated with increased risk of pain and complications. Objectives To determine the benefits and harms of tourniquet use in knee replacement surgery. Search methods We searched MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) up to 26 March 2020. We searched clinicaltrials.gov, the World Health Organization trials portal, and several international registries and joint registries up to March 2020. Selection criteria We included randomised controlled trials (RCTs) comparing knee replacement with use of a tourniquet versus without use of a tourniquet and non‐randomised studies with more than 1000 participants. Major outcomes included pain, function, global assessment of success, health‐related quality of life, serious adverse events (including venous thromboembolism, infection, re‐operation, and mortality), cognitive function, and survival of the implant. Minor outcomes included blood loss, economic outcomes, implant stability, and adverse events. Data collection and analysis Two review authors screened abstracts and full texts, extracted data, performed risk of bias assessments, and assessed the certainty of the evidence using the GRADE approach. Main results We included 41 RCTs with 2819 participants. Trials included from 20 to 199 participants. Mean age ranged between 58 and 84 years. More than half of the RCTs had unclear risk of selection bias and unclear risk of performance and detection bias due to absence of blinding of participants and surgeons. Major outcomes Pain: at postoperative day 1, pain (on a scale from zero to 10, with higher scores indicating worse pain) was ranked at 4.56 points after surgery without a tourniquet and at 1.25 points (MD) higher (95% CI 0.32 higher to 2.19 higher) with a tourniquet (8 studies; 577 participants), for an absolute difference of 12.5% higher pain scores (95% CI 3.2% higher to 21.9% higher) and a relative difference of 19% higher pain scores (95% CI 3.4% higher to 49% higher) with a tourniquet. Evidence for these findings was of moderate certainty, downgraded due to risk of bias. Knee replacement with a tourniquet probably led to higher postoperative pain scores at day 1, although this difference may or may not be noticeable to patients (based on a minimal clinically important difference (MCID) of 1.0). Function: at 12 months, tourniquet use probably makes little or no difference to function, based on an MCID of 5.3 for Knee Society Score (KSS) and 5.0 for Oxford Knee Score (OKS). Mean function (on a scale from 0 to 100, with higher scores indicating better outcomes) was 90.03 points after surgery without a tourniquet and was 0.29 points worse (95% CI 1.06 worse to 0.48 better) on a 0 to 100 scale, absolute difference was 0.29% worse (1.06% worse to 0.48% better), with a tourniquet (5 studies; 611 participants). This evidence was downgraded to moderate certainty due to risk of bias. Global assessment of success: low‐certainty evidence (downgraded due to bias and imprecision) indicates that tourniquet use may have little or no effect on success. At six months, 47 of 50 (or 940 per 1000) reported overall successful treatment after surgery without a tourniquet and 47 of 50 (or 940 per 1000) with a tourniquet (risk ratio (RR) 1.0, 95% CI 0.91 to 1.10) based on one study with 100 participants. Health‐related quality of life: at six months, tourniquet may have little or no effect on quality of life. The 12‐Item Short Form Survey (SF‐12) score (mental component from zero to 100 (100 is best)) was 54.64 after surgery without a tourniquet and 1.53 (MD) better (95% CI 0.85 worse to 3.91 better) with a tourniquet (1 study; 199 participants); absolute difference was 1.53% better (0.85% worse to 3.91% better). Evidence was of low certainty, downgraded due to risk of bias and small number of participants. Serious adverse events: the risk of serious adverse events was probably higher with tourniquet; 26 of 898 (29 per 1000) reported events following surgery without a tourniquet compared to 53 of 901 (59 per 1000) with a tourniquet (RR 1.73, 95% CI 1.10 to 2.73) in 21 studies (1799 participants). Twenty‐nine more per 1000 patients (95% CI 3 to 50 more per 1000 patients) had a serious adverse event with a tourniquet. Forty‐eight (95% CI 20 to 345) participants would need to have surgery without a tourniquet to avoid one serious adverse event. This evidence was downgraded to moderate certainty due to risk of bias. Cognitive function: one study reported cognitive function as an outcome; however the data were incompletely reported and could not be extracted for analysis. Survival of implant: it is uncertain if tourniquet has an effect on implant survival due to very low certainty evidence (downgraded for bias, and twice due to very low event rates); 2 of 107 (19 per 1000) required revision surgery in the surgery with a tourniquet group compared to 1 of 107 (9 per 1000) without a tourniquet group at up to two years' follow‐up (RR 1.44, 95% CI 0.23 to 8.92). This equates to a 0.4% (0.7% lower to 7% more) increased absolute risk in surgery with a tourniquet. Authors' conclusions Moderate certainty evidence shows that knee replacement surgery with a tourniquet is probably associated with an increased risk of serious adverse events. Surgery with a tourniquet is also probably associated with higher postoperative pain, although this difference may or may not be noticeable to patients. Surgery with a tourniquet does not appear to confer any clinically meaningful benefit on function, treatment success or quality of life. Further research is required to explore the effects of tourniquet use on cognitive function and implant survival, to identify any additional harms or benefits. If a tourniquet continues to be used in knee replacement surgery, patients should be informed about the potential increased risk of serious adverse events and postoperative pain.</p

    Linking Auxin with Photosynthetic Rate via Leaf Venation

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    International audienceLand plants lose vast quantities of water to the atmosphere during photosynthetic gas exchange. In angiosperms, a complex network of veins irrigates the leaf, and it is widely held that the density and placement of these veins determines maximum leaf hydraulic capacity and thus maximum photosynthetic rate. This theory is largely based on interspecific comparisons and has never been tested using vein mutants to examine the specific impact of leaf vein morphology on plant water relations. Here we characterize mutants at the Crispoid (Crd) locus in pea (Pisum sativum), which have altered auxin homeostasis and activity in developing leaves, as well as reduced leaf vein density and aberrant placement of free-ending veinlets. This altered vein phenotype in crd mutant plants results in a significant reduction in leaf hydraulic conductance and leaf gas exchange. We find Crispoid to be a member of the YUCCA family of auxin biosynthetic genes. Our results link auxin biosynthesis with maximum photosynthetic rate through leaf venation and substantiate the theory that an increase in the density of leaf veins coupled with their efficient placement can drive increases in leaf photosynthetic capacity

    The future for beef

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    Beef is a fast-growing, multi -billion dollar industry today in the United States. And the outlook for tomorrow is most favorable. Beef consumption has increased by 26 pounds per capita during the past 15 years, hitting an all-time high of 90 pounds per capita in 1962. During the same period quality has improved, and now. beef commands even wider consumer acceptance than in the mid-1940\u27s. New technology has lowered production and marketing costs. But even a strong, healthy industry must be sensitive to change--and take advantage of new opportunities for growth and improvement. The beef industry is no exception.https://lib.dr.iastate.edu/card_reports/1016/thumbnail.jp
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