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Current understanding of global late Quaternary fire history is largely drawn from sedimentary charcoal data. Since publication, CharAnalysis increasingly has been relied upon as a robust method for analyzing these data. However, several underlying assumptions of the algorithm have not been tested. This study uses replicated charcoal count data to examine the assumption of Poisson distribution and reproducibility of peak detection. Results show <10% of the replicate counts are Poisson distributed, a maximum peak replication rate of 60%, and, for >90% of the data, intra-level count differences were larger than the threshold used to identify significance in inter-level differences. A pronounced “edge effect” was observed at the beginning and end of the records, cautioning against validation of results based on sections corresponding to the historical period. The proximal cause for low reproducibility is likely a lack of spatial randomness of charcoal particles at the scale of a core diameter. Until and unless decomposition methods can be developed that accommodate the observed limitations inherent in particle count data, best practices for interpreting charcoal records may be to rely on qualitative interpretations based on smoothed influx values and minimum particle count values in the hundreds.
Microvascular health is a main determinant of coronary blood flow reserve and myocardial vascular resistance. Extracardiac capillary abnormality has been reported in subjects at increased coronary heart disease risk, such as prehypertension, hypertension, diabetes, hyperlipidemia, and atherosclerosis. We have reported cardiovascular dysfunction in a cohort of maternal nutrient reduction (MNR)-induced intrauterine growth restriction (IUGR) baboon offspring. Here we test the hypothesis that there is oral capillary rarefaction associated with MNR-induced IUGR. Capillary density was quantified using in vivo high-power capillaroscopy on seven middle-aged (~10.7 yr; human equivalent ~40 yr) male IUGR baboons and seven male age-matched controls in the lateral buccal and inferior labial mucosa. While no difference was found between groups in either area by fraction area or optical density for these vascular beds derived from fetal preductal vessels, further studies are needed on post-ductal vascular beds, retina, and function.
The objective of this study was to investigate whether different staffing models are associated with variation in radiograph use for children seen for bronchiolitis, croup, and asthma and discharged home from emergency departments (EDs) in Ontario.
Methods:
We surveyed all Ontario EDs regarding physician staffing models and use of clinical protocols. We used a population-based ED database to determine radiograph rates and patient characteristics. Regression techniques that controlled for patient factors and clustering within EDs were applied.
Results:
From April 2004 to March 2006, 5,186, 10,408, and 35,150 children were discharged home from an ED with bronchiolitis, croup, and asthma, respectively. Radiograph rates were 42.7% for bronchiolitis, 10.1% for croup, and 25.9% for asthma. Over 50% of children were treated in EDs with nonpediatric front-line care but with consultant pediatricians available. Compared to children in these settings, those seen in EDs with front-line pediatric staff were less likely to have radiographs for all three conditions (adjusted odds ratios [ORs] 0.47 [95% CI 0.24–0.95], 0.47 [95% CI 0.27–0.82], 0.13 [95% CI 0.02–0.66] for bronchiolitis, croup, and asthma, respectively). Children in community hospitals with pediatricians were significantly more likely to have a radiograph if seen by a consultant pediatrician (OR 1.40, 95% CI 1.20–1.63 [bronchiolitis]; OR 2.76, 95% CI 2.16–3.53 [croup]; and OR 1.97, 95% CI 1.64–2.36 [asthma]). We found no association between clinical protocol use and radiograph rates.
Conclusions:
High rates of discretionary radiograph use exist for common respiratory problems of children seen across ED settings. Quality improvement efforts should be focused in this area, and radiograph use in EDs staffed by front-line pediatrics-trained staff could serve as an initial benchmark target for other institutions.
The evaluation of emergency department (ED) quality of care is hampered by the absence of consensus on appropriate measures. We sought to develop a consensus on a prioritized and parsimonious set of evidence-based quality of care indicators for EDs.
Methods:
The process was led by a nationally representative steering committee and expert panel (representatives from hospital administration, emergency medicine, health information, government, and provincial quality councils). A comprehensive review of the scientific literature was conducted to identify candidate indicators. The expert panel reviewed candidate indicators in a modified Delphi panel process using electronic surveys; final decisions on inclusion of indicators were made by the steering committee in a guided nominal group process with facilitated discussion. Indicators in the final set were ranked based on their priority for measurement. A gap analysis identified areas where future indicator development is needed. A feasibility study of measuring the final set of indicators using current Canadian administrative databases was conducted.
Results:
A total of 170 candidate indicators were generated from the literature; these were assessed based on scientific soundness and their relevance or importance. Using predefined scoring criteria in two rounds of surveys, indicators were coded as “retained” (53), “discarded” (78), or “borderline” (39). A final set of 48 retained indicators was selected and grouped in nine categories (patient satisfaction, ED operations, patient safety, pain management, pediatrics, cardiac conditions, respiratory conditions, stroke, and sepsis or infection). Gap analysis suggested the need for new indicators in patient satisfaction, a healthy workplace, mental health and addiction, elder care, and community-hospital integration. Feasibility analysis found that 13 of 48 indicators (27%) can be measured using existing national administrative databases.
Discussion:
A broadly representative modified Delphi panel process resulted in a consensus on a set of 48 evidencebased quality of care indicators for EDs. Future work is required to generate technical definitions to enable the uptake of these indicators to support benchmarking, quality improvement, and accountability efforts.
We consider a model for the solidification of an ideal ternary alloy in a mushy layer that incorporates the effects of thermal and solutal diffusion, convection and solidification. Our results reveal that although the temperature and solute fields are constrained to the liquidus surface of the phase diagram, the system still admits double-diffusive modes of instability. Additionally, modes of instability exist even in situations in which the thermal and solute fields are each individually stable from a static point of view. We identify these instabilities for a general model in which the base-state solution and its linear stability are computed numerically. We then highlight these instabilities in a much simpler model that admits an analytical solution.
This paper investigates factors affecting the distribution of psychiatric morbidity in the community. It identifies a close relationship between mean Chronic General Health Questionnaire (CGHQ) scores in subdivisions of a large random sample of the community (the Health and Lifestyle Survey, N = 6317) and the prevalence in these groups of abnormal, above-threshold CGHQ scores. The frequency distributions of CGHQ scores in these different populations move up and down as a whole: like other physiological and behavioural attributes, these mental health outcomes in individuals are associated with characteristics of the populations in which they arise. Populations thus carry a collective responsibility for their own mental health and well-being. This implies that explanations for the differing prevalence rates of psychiatric morbidity must be sought in the characteristics of their parent populations; and control measures are unlikely to succeed if they do not involve population-wide changes.
We develop a complete set of equations governing the evolution of a sharp interface separating two fluid phases undergoing transformation. In addition to the conventional balances for mass, linear momentum and energy these equations include also a counterpart of the Gibbs–Thomson equation familiar from theories for crystal growth. This additional equation arises from a consideration of configurational forces within a thermodynamical framework. Although the notion of configurational forces is well-developed and understood for the description of materials, such as crystalline solids, that possess natural reference configurations, little has been done regarding their role in materials, such as viscous fluids, that do not possess preferred reference states. We therefore provide a comprehensive discussion of configurational forces, the balance of configurational momentum, and configurational thermodynamics that does not require a choice of reference configuration. The general evolution equations arising from our theory account for the thermodynamic structure of the bulk phases and the interface and for viscous and thermal dissipation in the bulk phases and for viscous dissipation on the interface. Because of the complexity of these equations, we provide a reduced system of equations based on simplified constitutive assumptions and approximations common in the literature on phase transformations. Using these reduced equations, we apply the theory to the radially symmetric problem for the condensation of a liquid drop into the vapour phase.