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The stability properties of a natural convection boundary layer adjacent to an isothermally heated vertical wall, with Prandtl number 0.71, are numerically investigated in the configuration of a temporally evolving parallel flow. The instantaneous linear stability of the flow is first investigated by solving the eigenvalue problem with a quasi-steady assumption, whereby the unsteady base flow is frozen in time. Temporal responses of the discrete perturbation modes are numerically obtained by solving the two-dimensional linearized disturbance equations using a ‘frozen’ base flow as an initial-value problem at various
is the Grashof number based on the velocity integral boundary layer thickness
. The resultant amplification rates of the discrete modes are compared with the quasi-steady eigenvalue analysis, and both two-dimensional and three-dimensional direct numerical simulations (DNS) of the temporally evolving flow. The amplification rate predicted by the linear theory compares well with the result of direct numerical simulation up to a transition point. The extent of the linear regime where the perturbations linearly interact with the base flow is thus identified. The value of the transition
, according to the three-dimensional DNS results, is dependent on the initial perturbation amplitude. Beyond the transition point, the DNS results diverge from the linear stability predictions as nonlinear mechanisms become important.
Introduction: Opioid side effects are common when treating chronic pain. However, the rate of opioid side effects for acute pain has rarely been examined, particularly in the post emergency department (ED) setting. The objective of this study was to evaluate the short-term incidence of opioid induced side effects (constipation, nausea/vomiting, dizziness, and drowsiness) in patients discharged from the ED with an opioid prescription. Methods: This was a prospective cohort study of patients aged ≥18 years that visited the ED for an acute pain condition (≤ 2 weeks) and were discharged with an opioid prescription. Patients completed a 14-day diary assessing daily pain medication use and side effects. Results: Mean age of the 386 patients included was 55 ± 16 years; 50% were women. During the 2-week follow-up, 80% of patients consumed at least one dose of opioids. Among the patients who used opioids, 38% (95%CI: 33-48) reported constipation, 27% (95%CI:22-32) nausea/vomiting, 30% (95%CI:25-35) dizziness, 51% (95%CI:45-57) drowsiness, and 77% (95%CI:72-82) reported any side effects. Adjusting for age, sex, and pain condition, patients who used opioids were more likely to report any side effect (OR 7.5, 95%CI:4.3-13.3) and constipation (OR 7.5, 95%CI:3.1-17.9). A significant dose response effect was observed for constipation but not for the other side effects. Nausea/vomiting (OR 2.0, 95%CI:1.1-3.6) and dizziness (OR 1.9, 95%CI:1.1-3.4) were associated with oxycodone compared to morphine. Conclusion: Similar to chronic pain, opioid side effects are highly prevalent during short-term treatment for acute pain. Physicians should be aware and inform patients about those side effects.
Characterising the three-dimensional (3D) distribution of hydraulic conductivity and its variability in the shallow subsurface is fundamental to understanding groundwater behaviour and to developing conceptual and numerical groundwater models to manage the subsurface. However, directly measuring in situ hydraulic conductivity can be difficult and expensive and is rarely carried out with sufficient density in urban environments. In this study we model hydraulic conductivity for 603 sites in the unconsolidated Quaternary deposits underlying Glasgow using particle size distribution and density description widely available from geotechnical investigations. Six different models were applied and the MacDonald formula was found to be most applicable in this heterogeneous environment, comparing well with the few available in situ hydraulic conductivity data. The range of the calculated hydraulic conductivity values between the 5th and 95th percentile was 1.56×10–2–4.38mday–1 with a median of 2.26×10–1 mday–1. These modelled hydraulic conductivity data were used to develop a suite of stochastic 3D simulations conditioned to existing 3D representations of lithology. Ten per cent of the input data were excluded from the modelling process for use in a split-sample validation test, which demonstrated the effectiveness of this approach compared with non-spatial or lithologically unconstrained models. Our spatial model reduces the mean squared error between the estimated and observed values at the excluded data locations over those predicted using a simple homogeneous model by 73 %. The resulting 3D hydraulic conductivity model is of a much higher resolution than would have been possible from using only direct measurements, and will improve understanding of groundwater flow in Glasgow and reduce the spatial uncertainty of hydraulic parameters in groundwater process models. The methodology employed could be replicated in other regions where significant volumes of suitable geotechnical and site investigation data are available to predict ground conditions in areas with complex superficial deposits.
Introduction: Gastroenteritis accounts for 1.7 million emergency department visits by children annually in the United States. We conducted a double-blind trial to determine whether twice daily probiotic administration for 5 days, improves outcomes. Methods: 886 children aged 348 months with gastroenteritis were enrolled in six Canadian pediatric emergency departments. Participants were randomly assigned to twice daily Lactobacillus rhamnosus R0011 and Lactobacillus helveticus R0052, 4.0 x 109 CFU, in a 95:5 ratio or placebo. Primary outcome was development of moderate-severe disease within 14 days of randomization defined by a Modified Vesikari Scale score 9. Secondary outcomes included duration of diarrhea and vomiting, subsequent physician visits and adverse events. Results: Moderate-severe disease occurred in 108 (26.1%) participants administered probiotics and 102 (24.7%) participants allocated to placebo (OR 1.06; 95%CI: 0.77, 1.46; P=0.72). After adjustment for site, age, and frequency of vomiting and diarrhea, treatment assignment did not predict moderate-severe disease (OR, 1.11, 95%CI, 0.80 to 1.56; P=0.53). In the probiotic versus placebo groups, there were no differences in the median duration of diarrhea [52.5 (18.3, 95.8) vs. 55.5 (20.2, 102.3) hours; P=0.31], vomiting [17.7 (0, 58.6) vs. 18.7 (0, 51.6) hours; P=0.18], physician visits (30.2% vs. 26.6%; OR 1.19; 95% CI0.87. 1.62; P=0.27), or adverse events (32.9% vs. 36.8%; OR 0.83; 95%CI 0.62. 1.11; P=0.21). Conclusion: In children presenting to an emergency department with gastroenteritis, twice daily administration of 4.0 x 109 CFU of a Lactobacillus rhamnosus/helveticus probiotic does not prevent development of moderate-severe disease or improvements in other outcomes measured.
Introduction: Outside of key conditions such as cardiac arrest and trauma, little is known about the epidemiology of mortality of all transported EMS patients. The objective of this study is to describe characteristics of EMS patients who after transport die in a health care facility. Methods: EMS transport events over one year (April, 2015-16) from a BLS/ALS system serving an urban/rural population of approximately 2 million were linked with in-hospital datasets to determine proportion of all-cause in-hospital mortality by Medical Priority Dispatch System (MPDS) determinant (911 call triage system), age in years (>=18 yrs. - adult, <=17 yrs. - pediatric), sex, day of week, season, time (in six hour periods), and emergency department Canadian Triage and Acuity Scale (CTAS). The MPDS card, patient chief complaint, and ED diagnosis category (International Classification of Disease v.10 - Canadian) with the highest proportion of mortality are also reported. Analyses included two-sided t-test or chi-square with alpha <0.05. Results: A total of 239,534 EMS events resulted in 159,507 patient transports; 141,114 were included for analysis after duplicate removal (89.1% linkage), with 127,867 reporting final healthcare system outcome. There were 4,269 who died (3.3%; 95%CI 3.2%, 3.4%). The proportion of mortality by MPDS determinant was, from most to least critical 911 call, Echo (7.3%), Delta (37.2%), Charlie (31.3%), Bravo (5.8%), Alpha (18.3%), and Omega (0.3%). For adults the mean age of survivors was less than non-survivors (57.7 vs. 75.8; p<0.001), but pediatric survivors were older than non-survivors (8.7 vs. 2.8; p<0.001). There were more males that died than females (53.0% vs. 47.0%; p<0.001). There was no statistically significant difference in the day of week (p=0.592), but there was by season with the highest mortality in winter (27.1%; p=0.045). The highest mortality occurred with patients presenting to EMS between 0600-1200 hours (34.6%), and the lowest between 0000-0600 hours (11.8%; p<0.001). Mortality by CTAS was category 1 (27.1%), 2 (36.7%), 3 (29.9%), 4 (4.3%), and 5 (0.5%). The highest mortality was seen in MPDS card 26-Sick Person (specific diagnosis) (19.1%), chief complaint shortness of breath (19.3%), and ED diagnoses pertaining to the circulatory system (31.1%). Conclusion: Significant all-cause in-hospital mortality differences were found between event, patient, and clinical characteristics. These data provide foundational and hypothesis generating knowledge regarding mortality in transported EMS patients that can be used to guide research and training. Future research should further explore the characteristics of those that access health care through the EMS system.
Introduction: Community Paramedics (CPs) require access to timely blood analysis in the field to guide treatment and transport decisions. Point of care testing (POCT), as opposed to traditional laboratory analysis, may offer a solution, but limited research exists on CP POCT. The objective of this study is to compare the validity of two POCT devices (Abbott i-STAT® and Alere epoc®) and their use by CPs in the community. Methods: In a CP programme responding to 6,000 annual patient care events, a split sample validation of POCT against traditional laboratory analysis for seven analytes (sodium, potassium, chloride, creatinine, hemoglobin, hematocrit, and glucose) was conducted on a consecutive sample of patients. The difference of proportion of discrepant results between POCT and laboratory was compared using a two sample proportion test. Usability was analysed by survey of CP experience, an expert heuristic evaluation of devices, a review of device-logged errors, coded observations of POCT use during quality control testing, and a linear mixed effects model of Systems Usability Scale (SUS) adjusted for CP clinical and POCT experience. Results: Of 1,649 CP calls for service screened for enrollment, 174 had a blood draw, with 108 patient care encounters (62.1%) enrolled from 73 participants. Participants had a mean age of 58.7 years (SD16.3); 49% were female. In 4 of 646 (0.6%) individual comparisons, POCT reported a critical value that the laboratory did not; with no statistically significant difference in the number of discrepant critical values reported with epoc® compared to i-STAT®. There were no instances of the laboratory reporting a critical value when POCT did not. In 88 of 1,046 (8.4%) individual comparisons, the a priori defined acceptable difference between POCT and the laboratory was exceeded; occurring more often in epoc® (10.7%;95%CI:8.1%,13.3%) compared to i-STAT® (6.1%;95%CI:4.1%,8.2%)(p=0.007). Eighteen of 19 CP surveys were returned, with 11/18 (61.1%) preferring i-STAT® over epoc®. The i-STAT® had a higher mean SUS score (higher usability) compared to the epoc® (84.0/100 vs. 59.6/100; p=0.011). Fewer field blood analysis device-logged errors occurred in i-STAT® (7.8%;95%CI:2.9%,12.7%) compared to epoc® (15.5%;95%CI:9.3%,21.7%) although not statistically significant (p=0.063). Conclusion: CP programs can expect valid results from POCT. Usability assessment suggests a preference for i-STAT.
Acute rheumatic fever (ARF) continues to produce a significant burden of disease in New Zealand (NZ) Māori and Pacific peoples. Serious limitations in national surveillance data mean that accurate case totals cannot be generated. Given the changing epidemiology of ARF in NZ and the major national rheumatic fever prevention programme (2012–2017), we updated our previous likely true case number estimates using capture–recapture analyses. Aims were to estimate the likely true incidence of ARF in NZ and comment on the changing ability to detect cases. Data were obtained from national hospitalisation and notification databases. The Chapman Estimate partially adjusted for bias. An estimated 2342 likely true new cases arose from 1997 to 2015, giving a mean annual incidence of 2·9 per 100 000 (95% CI 2·5–3·5). Compared with the pre-intervention (2009–2011) baseline incidence (3·4 per 100 000, 95% CI 2·9–4·0), the likely true 2015 incidence declined 44%. Large gaps in data completeness are slowly closing. During the period 2012–2015, 723 cases were identified; 83·8% of notifications were matched to hospitalisation data, and 87·2% of hospitalisations matched to notifications. Despite this improvement, clinicians need to remain aware of the need to notify atypical patients. A possible unintended consequence of the national ARF prevention programme is increased misdiagnosis.
An updated compilation of published and new data of major-ion (Ca, Cl, K, Mg, Na, NO3, SO4) and methylsulfonate (MS) concentrations in snow from 520 Antarctic sites is provided by the national ITASE (International Trans-Antarctic Scientific Expedition) programmes of Australia, Brazil, China, Germany, Italy, Japan, Korea, New Zealand, Norway, the United Kingdom, the United States and the national Antarctic programme of Finland. The comparison shows that snow chemistry concentrations vary by up to four orders of magnitude across Antarctica and exhibit distinct geographical patterns. The Antarctic-wide comparison of glaciochemical records provides a unique opportunity to improve our understanding of the fundamental factors that ultimately control the chemistry of snow or ice samples. This paper aims to initiate data compilation and administration in order to provide a framework for facilitation of Antarctic-wide snow chemistry discussions across all ITASE nations and other contributing groups. The data are made available through the ITASE web page (http://www2.umaine.edu/itase/content/syngroups/snowchem.html) and will be updated with new data as they are provided. In addition, recommendations for future research efforts are summarized.
Samples of snow and firn from accumulation zones on Clark, Commonwealth, Blue and Victoria Upper Glaciers in the McMurdo Dry Valleys (∼77–78º S, 161–164º E), Antarctica, are evaluated chemically and isotopically to determine the relative importance of local (site-specific) factors vs regional-scale influences in defining glaciochemistry. Spatial variation in snow and firn chemistry confirms documented trends within individual valleys regarding major-ion deposition relative to elevation and to distance from the coast. Sodium and methylsulfonate (MS–), for example, follow a decreasing gradient with distance from the coast along the axis of Victoria Valley (350–119 µg L−1 for Na+; 33–14 µg L−1 for MS–); a similar pattern exists between Commonwealth and Newall Glaciers in the Asgaard Range. When comparing major-ion concentrations (e.g. Na+, MS−, Ca2+) or trace metals (e.g. Al, Fe) among different valleys, however, site-specific exposures to marine and local terrestrial chemical sources play a dominant role. Because chemical signals at all sites respond to particulates with varying mixtures of marine and terrestrial sources, each of these influences on site glaciochemistry must be considered when drawing temporal climate inferences on regional scales.
Conducting archaeological fieldwork increasingly relies on “high-tech” instruments. These include such technologies as portable X-ray diffraction; ground penetrating radar; high-precision global navigation satellite system (GNSS) receivers; laser scanners; multispectral, thermal, lidar, and hyperspectral instruments on Uncrewed Aerial Vehicles (UAVs); and many others. Using these devices internationally can present complex issues with export regulations and the potential for duties and value-added taxes. In short, there are many regulations affecting the movement of these devices across international borders. In the past, archaeologists had interactions with customs personnel and faced the complexities of import and export laws at the end of a project, as they dealt with the issues of taking samples or artifacts out of a country for study. Today's archaeologists must be prepared before they even begin their travel to ensure that their equipment and software can travel overseas. This article provides a practical overview of the laws, regulations, and practices affecting international transport of the archaeological high-tech tool kit.
We report on an effort to identify further members of the dwarf carbon class and new members of a putative dwarf S group in the general field through determination of proper motions of catalogued stars. Examination of nearly 1500 C stars and over 300 S stars reveals some interesting false alarms but no new dwarf members of these classes.
We describe a program of determining proper motions from digitized scans of Palomar Oschin Schmidt telescope plates at the Space Telescope Science Institute. Our method is most useful over 11 ≲ V ≲ 18 and .
In an attempt to distill what we know about the effects of workplace mindfulness-based training, Hyland, Lee, and Mills (2015) cast a wide net with regard to the array of studies included in their review. For example, they include studies that investigate the benefits associated with workplace mindfulness training (e.g., Wolever et al., 2012) as well as training conducted for patients within primary care settings (e.g., Allen, Bromley, Kuyken, & Sonnenberg, 2009). In addition, their review includes studies based on self-reports of individual differences in mindfulness traits/skills (e.g., Hafenbrack, Kinias, & Barsade, 2014). Reviewing a broad cross-section of research is helpful to illustrate the wide-ranging nature of mindfulness research but also has the potential to obfuscate what we know about mindfulness as it pertains to workers and workplaces.