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Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.
Using especially designed laboratory experiments, we demonstrate that the flow-driven deformation of sufficiently porous, wall-mounted, flexible plates can exhibit positive Vogel exponent
, i.e. drag proportional to the
power of the incoming flow velocity. High-resolution force balance, planar particle image velocimetry and particle tracking velocimetry are used to measure the drag force, flow characteristics and plate bending. For a flexible plate with relatively high porosity given by an array of regularly spaced square openings, we derive a simple analytical argument that accounts for the sub-quadratic trends of the drag in a range of flow velocities spanning one order of magnitude. There, the drag experienced by the structure is modulated by the contributions of the local structure containing an open area. The effective approach velocity for each of these sections appears to increase monotonically with increased structure deformation due to the reduced effect of local wakes produced by adjacent areas. The uncovered aerodynamic behaviour may help to understand the complex flow–structure interaction of perforated structures in nature and engineering.
Enterococcus causes clinically significant bloodstream infections (BSIs). In centers with a higher prevalence of vancomycin resistant enterococcus (VRE) colonization, a common clinical question is whether empiric treatment directed against VRE should be initiated in the setting of a suspected enterococcal BSI. Unfortunately, VRE treatment options are limited, and relatively expensive, and subject patients to the risk of adverse reactions. We hypothesized that the results of VRE colonization screening could predict vancomycin resistance in enterococcal BSI.
We reviewed 370 consecutive cases of enterococcal BSI over a 7-year period at 2 tertiary-care hospitals to determine whether vancomycin-resistant BSIs could be predicted based on known colonization status (ie, patients with swabs performed within 30 days, more remotely, or never tested). We calculated sensitivity and specificity, and we plotted negative predictives values (NPVs) and positive predictive values (PPVs) as a function of prevalence.
A negative screening swab within 30 days of infection yielded NPVs of 90% and 95% in settings where <27.0% and 15.0% of enterococcal BSI are resistant to vancomycin, respectively. In patients with known VRE colonization, the PPV for VRE in enterococcal BSI was >50% at any prevalence exceeding 25%.
The results of a negative VRE screening test result performed within 30 days can help eliminate unnecessary empiric therapy in patients with suspected enterococcal BSI. Conversely, patients with positive VRE screening swabs require careful consideration of empiric VRE-directed therapy when enterococcal BSI appears likely.
To describe an outbreak of bacteremia caused by vancomycin-sensitive Enterococcus faecalis (VSEfe).
An investigation by retrospective case control and molecular typing by whole-genome sequencing (WGS).
A tertiary-care neonatal unit in Melbourne, Australia.
Risk factors for 30 consecutive neonates with VSEfe bacteremia from June 2011 to December 2014 were analyzed using a case control study. Controls were neonates matched for gestational age, birth weight, and year of birth. Isolates were typed using WGS, and multilocus sequence typing (MLST) was determined.
Bacteremia for case patients occurred at a median time after delivery of 23.5 days (interquartile range, 14.9–35.8). Previous described risk factors for nosocomial bacteremia did not contribute to excess risk for VSEfe. WGS typing results designated 43% ST179 as well as 14 other sequence types, indicating a polyclonal outbreak. A multimodal intervention that included education, insertion checklists, guidelines on maintenance and access of central lines, adjustments to the late onset sepsis antibiotic treatment, and the introduction of diaper bags for disposal of soiled diapers after being handled inside the bed, led to termination of the outbreak.
Typing using WGS identified this outbreak as predominately nonclonal and therefore not due to cross transmission. A multimodal approach was then sought to reduce the incidence of VSEfe bacteremia.
Free surface oscillations in a narrow gap between elongated parallel bodies are studied numerically. As this represents both a highly resonant system and an arrangement of relevance to offshore operations, the nature of the damping is of primary interest, and has a critical role in determining the response. Previous experimental work has suggested that the damping could be attributed to laminar boundary layers; here our numerical wave tank successfully resolves both wave and boundary layer scales to provide strong numerical evidence in support of this conclusion. The simulations follow the experiments in using wave groups so that the computation is tractable, and both linear and second harmonic excitation of the gap are demonstrated.
The anatomy of the membranous labyrinth within the vestibule has direct implications for surgical intervention. The anatomy of the otoliths has been studied, but there is limited information regarding their supporting connective tissue structures such as the membrana limitans in humans.
One guinea pig and 17 cadaveric human temporal bones were scanned using micro computed tomography, after staining with 2 per cent osmium tetroxide and preservation with Karnovsky's solution, with a resolution from 1 µm to 55 µm. The data were analysed using VGStudio Max software, rendered in three-dimensions and published in augmented reality.
In 50 per cent of ears, the membrana limitans attached directly to the postero-superior part of the stapes footplate. If attachments were present in one ear, they were present bilaterally in 100 per cent of cases.
Micro computed tomography imaging allowed three-dimensional assessment of the inner ear. Such assessments are important as they influence the surgical intervention and the evolution of future innovations.
We sought to assess the presence and reporting quality of peer-reviewed literature concerning the accuracy, precision, and reliability of home monitoring technologies for vital signs and glucose determinations in older adult populations.
A narrative literature review was undertaken searching the databases Medline, Embase, and Compendex. Peer-reviewed publications with keywords related to vital signs, monitoring devices and technologies, independent living, and older adults were searched. Publications between the years 2012 and 2018 were included. Two reviewers independently conducted title and abstract screening, and four reviewers independently undertook full-text screening and data extraction with all disagreements resolved through discussion and consensus.
Two hundred nine articles were included. Our review showed limited assessment and low-quality reporting of evidence concerning the accuracy, precision, and reliability of home monitoring technologies. Of 209 articles describing a relevant device, only 45 percent (n = 95) provided a citation or some evidence to support their validation claim. Of forty-eight articles that described the use of a comparator device, 65 percent (n = 31) used low-quality statistical methods, 23 percent (n = 11) used moderate-quality statistical methods, and only 12 percent (n = 6) used high-quality statistical methods.
Our review found that current validity claims were based on low-quality assessments that do not provide the necessary confidence needed by clinicians for medical decision-making purposes. This narrative review highlights the need for standardized health technology reporting to increase health practitioner confidence in these devices, support the appropriate adoption of such devices within the healthcare system, and improve health outcomes.
The response of soil microbial communities to soil quality changes is a sensitive indicator of soil ecosystem health. The current work investigated soil microbial communities under different fertilization treatments in a 31-year experiment using the phospholipid fatty acid (PLFA) profile method. The experiment consisted of five fertilization treatments: without fertilizer input (CK), chemical fertilizer alone (MF), rice (Oryza sativa L.) straw residue and chemical fertilizer (RF), low manure rate and chemical fertilizer (LOM), and high manure rate and chemical fertilizer (HOM). Soil samples were collected from the plough layer and results indicated that the content of PLFAs were increased in all fertilization treatments compared with the control. The iC15:0 fatty acids increased significantly in MF treatment but decreased in RF, LOM and HOM, while aC15:0 fatty acids increased in these three treatments. Principal component (PC) analysis was conducted to determine factors defining soil microbial community structure using the 21 PLFAs detected in all treatments: the first and second PCs explained 89.8% of the total variance. All unsaturated and cyclopropyl PLFAs except C12:0 and C15:0 were highly weighted on the first PC. The first and second PC also explained 87.1% of the total variance among all fertilization treatments. There was no difference in the first and second PC between RF and HOM treatments. The results indicated that long-term combined application of straw residue or organic manure with chemical fertilizer practices improved soil microbial community structure more than the mineral fertilizer treatment in double-cropped paddy fields in Southern China.
Recent studies indicate that early postnatal period is a critical window for gut microbiota manipulation to optimise the immunity and body growth. This study investigated the effects of maternal faecal microbiota orally administered to neonatal piglets after birth on growth performance, selected microbial populations, intestinal permeability and the development of intestinal mucosal immune system. In total, 12 litters of crossbred newborn piglets were selected in this study. Litter size was standardised to 10 piglets. On day 1, 10 piglets in each litter were randomly allotted to the faecal microbiota transplantation (FMT) and control groups. Piglets in the FMT group were orally administrated with 2ml faecal suspension of their nursing sow per day from the age of 1 to 3 days; piglets in the control group were treated with the same dose of a placebo (0.1M potassium phosphate buffer containing 10% glycerol (vol/vol)) inoculant. The experiment lasted 21 days. On days 7, 14 and 21, plasma and faecal samples were collected for the analysis of growth-related hormones and cytokines in plasma and lipocalin-2, secretory immunoglobulin A (sIgA), selected microbiota and short-chain fatty acids (SCFAs) in faeces. Faecal microbiota transplantation increased the average daily gain of piglets during week 3 and the whole experiment period. Compared with the control group, the FMT group had increased concentrations of plasma growth hormone and IGF-1 on days 14 and 21. Faecal microbiota transplantation also reduced the incidence of diarrhoea during weeks 1 and 3 and plasma concentrations of zonulin, endotoxin and diamine oxidase activities in piglets on days 7 and 14. The populations of Lactobacillus spp. and Faecalibacterium prausnitzii and the concentrations of faecal and plasma acetate, butyrate and total SCFAs in FMT group were higher than those in the control group on day 21. Moreover, the FMT piglets have higher concentrations of plasma transforming growth factor-β and immunoglobulin G, and faecal sIgA than the control piglets on day 21. These findings indicate that early intervention with maternal faecal microbiota improves growth performance, decreases intestinal permeability, stimulates sIgA secretion, and modulates gut microbiota composition and metabolism in suckling piglets.
Introduction: Survival from cardiac arrest has been linked to the quality of resuscitation care. Unfortunately, healthcare providers frequently underperform in these critical scenarios, with a well-documented deterioration in skills weeks to months following advanced life support courses. Improving initial training and preventing decay in knowledge and skills are a priority in resuscitation education. The spacing effect has repeatedly been shown to have an impact on learning and retention. Despite its potential advantages, the spacing effect has seldom been applied to organized education training or complex motor skill learning where it has the potential to make a significant impact. The purpose of this study was to determine if a resuscitation course taught in a spaced format compared to the usual massed instruction results in improved retention of procedural skills. Methods: EMS providers (Paramedics and Emergency Medical Technicians (EMT)) were block randomized to receive a Pediatric Advanced Life Support (PALS) course in either a spaced format (four 210-minute weekly sessions) or a massed format (two sequential 7-hour days). Blinded observers used expert-developed 4-point global rating scales to assess video recordings of each learner performing various resuscitation skills before, after and 3-months following course completion. Primary outcomes were performance on infant bag-valve-mask ventilation (BVMV), intraosseous (IO) insertion, infant intubation, infant and adult chest compressions. Results: Forty-eight of 50 participants completed the study protocol (26 spaced and 22 massed). There was no significant difference between the two groups on testing before and immediately after the course. 3-months following course completion participants in the spaced cohort scored higher overall for BVMV (2.2 ± 0.13 versus 1.8 ± 0.14, p=0.012) without statistically significant difference in scores for IO insertion (3.0 ± 0.13 versus 2.7± 0.13, p= 0.052), intubation (2.7± 0.13 versus 2.5 ± 0.14, p=0.249), infant compressions (2.5± 0.28 versus 2.5± 0.31, p=0.831) and adult compressions (2.3± 0.24 versus 2.2± 0.26, p=0.728) Conclusion: Procedural skills taught in a spaced format result in at least as good learning as the traditional massed format; more complex skills taught in a spaced format may result in better long term retention when compared to traditional massed training as there was a clear difference in BVMV and trend toward a difference in IO insertion.
Introduction: The purpose of this study is to determine if the introduction of a pre-arrival and pre-departure Trauma Checklist as a cognitive aid, coupled with an educational session, will improve clinical performance in a simulated environment. The Trauma Checklist was developed in response to a quality assurance review of high-acuity trauma activations. It focuses on pre-arrival preparation and a pre-departure review prior to patient transfer to diagnostic imaging or the operating room. We conducted a pilot, randomized control trial assessing the impact of the Trauma Checklist on time to critical interventions on a simulated pediatric patient by multidisciplinary teams. Methods: Emergency department teams composed of 2 physicians, 2 nurses and 2 confederate actors were enrolled in our study. In the intervention arm, participants watched a 10-minute educational video modelling the use of the trauma checklist prior to their simulation scenario and were provided a copy of the checklist. Teams participated in a standardized simulation scenario caring for a severely injured adolescent patient with hemorrhagic shock, respiratory failure and increased intracranial pressure. Our primary outcome of interest was time measurement to initiation of key clinical interventions, including intubation, first blood product administration, massive transfusion protocol activation, initiation of hyperosmolar therapy and others. Secondary outcome measures included a Trauma Task Performance score and checklist completion scores. Results: We enrolled 14 multidisciplinary teams (n=56 participants) into our study. There was a statistically significant decrease in median time to initiation of hyperosmolar therapy by teams in the intervention arm compared to the control arm (581 seconds, [509-680] vs. 884 seconds, [588-1144], p=0.03). Time to initiation of other clinical interventions was not statistically significant. There was a trend to higher Trauma Task Performance scores in the intervention group however this did not reach statistical significant (p=0.09). Pre-arrival and pre-departure checklist scores were higher in the intervention group (9.0 [9.0-10.0] vs. 7.0 [6.0-8.0], p=0.17 and 12.0 [11.5-12.0] vs. 7.5 [6.0-8.5], p=0.01). Conclusion: Teams using the Trauma Checklist did not have decreased time to initiation of key clinical interventions except in initiating hyperosmolar therapy. Teams in the intervention arm had statistically significantly higher pre-arrival and pre-departure scores, with a trend to higher Trauma Task Performance scores. Our study was a pilot and recruitment did not achieve the anticipated sample size, thus underpowered. The impact of this checklist should be studied outside tertiary trauma centres, particularly in trainees and community emergency providers, to assess for benefit and further generalizability.
Introduction: Inspired by the Choosing Wisely® campaign, St. Michaels Hospital (SMH) launched an initiative to reduce unnecessary tests, treatments and procedures that may cause patient harm. Stakeholder engagement identified inappropriate ordering of urine culture & sensitivities (C&S) in the emergency department (ED) as a focus area. Inappropriate urine C&S increase workload, healthcare costs and detection of asymptomatic bacteriuria which can lead to unnecessary antibiotics. The project’s purposes were to describe the scope of inappropriately ordered urine C&S in the SMH ED and to conduct a root-cause analysis to inform future quality improvement interventions. Methods: Criteria for determining appropriateness was developed a priori using evidence-based guidelines from the University Health Network together with additional literature review. A retrospective chart review was performed on all urine C&S ordered in the ED from Jun 1 Aug 30, 2016. Each chart was reviewed for order appropriateness, demographic information and ordering provider. All inappropriate urine C&S were reviewed to identify root causes which were then grouped into common themes. A pareto chart was constructed to analyze the frequency of causes. Results: Of 425 urine C&S ordered, 75 (17.7%) were inappropriate. The top 3 reasons were: inappropriate urosepsis work-ups (53%), order processing errors (17%) and inappropriate work-ups for weakness (16%). Inappropriate urosepsis work-ups were defined as urine C&S that were ordered empirically despite there being a clear focus for infection elsewhere (i.e. cough, cellulitis) and in the absence of urinary symptoms. Order processing errors were defined as urine C&S which were sent despite there being no documented order. Inappropriate testing was more likely to occur overnight, in females and when a urine routine and microscopy was not ordered prior to C&S. 29% of patients with inappropriate C&S received antibiotics. Conclusion: 17.7% of urine C&S ordered in the SMH ED during the 3-month study period were inappropriate. The top cause was septic patients who were empirically tested despite having another source for infection identified from the outset. A possible reason for this is the recent ED emphasis on early recognition of sepsis which may encourage early use of antibiotics and empiric urine C&S. One question to resolve is whether a 17.7% overutilization rate is sufficient to make it a target for change. Interventions designed to reduce inappropriate urine C&S may inadvertently increase the number of missed cultures in patients admitted with sepsis not yet diagnosed. Next steps involve discussions between the ED, Internal Medicine, Infectious Disease and Microbiology, and patient partners to identify patient-centered change ideas and sustainable strategies. This may involve establishing guidelines for ordering urine C&S and incorporating lab services to provide oversight into urine C&S processing.
Little is known about terrestrial climate dynamics in the Levant during the penultimate interglacial-glacial period. To decipher the palaeoclimatic history of the Marine Oxygen Isotope Stage (MIS) 6 glacial period, a well-dated stalagmite (~194 to ~154 ka) from Kanaan Cave on the Mediterranean coast in Lebanon was analyzed for its petrography, growth history, and stable isotope geochemistry. A resolved climate record has been recovered from this precisely U–Th dated speleothem, spanning the late MIS 7 and early MIS 6 at low resolution and the mid–MIS 6 at higher resolution. The stalagmite grew discontinuously from ~194 to ~163 ka. More consistent growth and higher growth rates between ~163 and ~154 ka are most probably linked to increased water recharge and thus more humid conditions. More distinct layering in the upper part of the speleothem suggests strong seasonality from ~163 ka to ~154 ka. Short-term oxygen and carbon isotope excursions were found between ~155 and ~163 ka. The inferred Kanaan Cave humid intervals during the mid–MIS 6 follow variations of pollen records in the Mediterranean basins and correlate well with the synthetic Greenland record and East Asian summer monsoon interstadial periods, indicating short warm/wet periods similar to the Dansgaard-Oeschger events during MIS 4–3 in the eastern Mediterranean region.
Animal proteins are naturally 15N enriched relative to the diet and the extent of this difference (Δ15Nanimal-diet or N isotopic fractionation) has been correlated to N use efficiency (NUE; N gain or milk N yield/N intake) in some recent ruminant studies. The present study used meta-analysis to investigate whether Δ15Nanimal-diet can be used as a predictor of NUE across a range of dietary conditions, particularly at the level of between-animal variation. An additional objective was to identify variables related to N partitioning explaining the link between NUE and Δ15Nanimal-diet. Individual values from eight publications reporting both NUE and Δ15Nanimal-diet for domestic ruminants were used to create a database comprising 11 experimental studies, 41 treatments and individual animal values for NUE (n=226) and Δ15Nanimal-diet (n=291). Data were analyzed by mixed-effect regression analysis taking into account experimental factors as random effects on both the intercept and slope of the model. Diets were characterized according to the INRA feeding system in terms of N utilization at the rumen, digestive and metabolic levels. These variables were used in a partial least squares regression analysis to predict separately NUE and Δ15Nanimal-diet variation, with the objective of identifying common variables linking NUE and Δ15Nanimal-diet. For individuals reared under similar conditions (within-study) and at the same time (within-period), the variance of NUE and Δ15Nanimal-diet not explained by dietary treatments (i.e. between-animal variation plus experimental error) was 35% and 55%, respectively. Mixed-effect regression analysis conducted with treatment means showed that Δ15Nanimal-diet was significantly and negatively correlated to NUE variation across diets (NUE=0.415 −0.055×Δ15Nanimal-diet). When using individual values and taking into account the random effects of study, period and diet, the relationship was also significant (NUE=0.358 −0.035×Δ15Nanimal-diet). However, there may be a biased prediction for animals close to zero, or in negative, N balance. When using a novel statistical approach, attempting to regress between-animal variation in NUE on between-animal variation in Δ15Nanimal-diet (without the influence of experimental factors), the negative relationship was still significant, highlighting the ability of Δ15Nanimal-diet to capture individual variability. Among the studied variables related to N utilization, those concerning N efficiency use at the metabolic level contributed most to predict both Δ15Nanimal-diet and NUE variation, with rumen fermentation and digestion contributing to a lesser extent. This study confirmed that on average Δ15Nanimal-diet can predict NUE variation across diets and across individuals reared under similar conditions.
The Megamaser Cosmology Project (MCP) measures the Hubble Constant by determining geometric distances to circumnuclear 22 GHz H2O megamasers in galaxies at low redshift (z < 0.05) but well into the Hubble flow. In combination with the recent, exquisite observations of the Cosmic Microwave Background by WMAP and Planck, these measurements provide a direct test of the standard cosmological model and constrain the equation of state of dark energy. The MCP is a multi-year project that has recently completed observations and is currently working on final analysis. Based on distance measurements to the first four published megamasers in the sample, the MCP currently determines H0 = 69.3 ± 4.2 km s−1 Mpc−1. The project is finalizing analysis for five additional galaxies. When complete, we expect to achieve a ~4% measurement. Given the tension between the Planck prediction of H0 in the context of the standard cosmological model and astrophysical measurements based on standard candles, the MCP provides a critical and independent geometric measurement that does not rely on external calibrations or a distance ladder.