On the linear approximation of mixture internal energies of departure

Direct Monte Carlo simulation of internal energies of departure for binary mixtures of geological interest are gathered and compared to those calculated using a linear mixing rule. Simulation results for gas–oil, oil–oil, and oil–water mixtures show that the linear mixing rule used in the Gibbs–Helmholtz Constrained (GHC) equation of state framework gives accurate approximations of binary mixture internal energies of departure. A flowchart for computing internal energies of departure using Monte Carlo simulation is included along with a sensitivity analysis for the GHC mixture energy parameter with respect to uncertainty in internal energies of departure

Skeletal Muscle PGC-1β Signaling is Sufficient to Drive an Endurance Exercise Phenotype and to Counteract Components of Detraining in Mice

Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α and -1β serve as master transcriptional regulators of muscle mitochondrial functional capacity and are capable of enhancing muscle endurance when overexpressed in mice. We sought to determine whether muscle-specific transgenic overexpression of PGC-1β affects the detraining response following endurance training. First, we established and validated a mouse exercise-training-detraining protocol. Second, using multiple physiological and gene expression end points, we found that PGC-1β overexpression in skeletal muscle of sedentary mice fully recapitulated the training response. Lastly, PGC-1β overexpression during the detraining period resulted in partial prevention of the detraining response. Specifically, an increase in the plateau at which O2 uptake (V̇o2) did not change from baseline with increasing treadmill speed [peak V̇o2 (ΔV̇o2max)] was maintained in trained mice with PGC-1β overexpression in muscle 6 wk after cessation of training. However, other detraining responses, including changes in running performance and in situ half relaxation time (a measure of contractility), were not affected by PGC-1β overexpression. We conclude that while activation of muscle PGC-1β is sufficient to drive the complete endurance phenotype in sedentary mice, it only partially prevents the detraining response following exercise training, suggesting that the process of endurance detraining involves mechanisms beyond the reversal of muscle autonomous mechanisms involved in endurance fitness. In addition, the protocol described here should be useful for assessing early-stage proof-of-concept interventions in preclinical models of muscle disuse atrophy

The Communication Patterns Questionnaire-Short Form: A Review and Assessment

The Communication Patterns Questionnaire-Short Form (CPQ-SF) is an 11-item self-assessment of spouses’ perceptions of marital interactions. A cited reference review of the CPQ-SF literature revealed no formal assessment of its psychometric properties and that researchers are imprecise in their use, reporting, and referencing of the assessment. Toward improving the use of the CPQ-SF in research and practice, the factor structure and psychometric properties of this scale were examined with data collected from a diverse sample of married individuals. Three latent constructs were identified: criticize/defend, discuss/avoid, and positive interaction patterns. Support for the original two-factor structure, demand/withdrawal and positive interaction, was also found. Suggestions for a more precise use of the CPQ-SF in research and practice conclude the paper

Pediatric interfacility transport effects on mortality and length of stay

BackgroundWe aimed to evaluate the effects of interfacility pediatric critical care transport response time, physician presence during transport, and mode of transport on mortality and length of stay (LOS) among pediatric patients. We hypothesized that a shorter response time and helicopter transports, but not physician presence, are associated with lower mortality and a shorter LOS.MethodsRetrospective, single-center, cohort study of 841 patients (< 19 years) transported to a quaternary pediatric intensive care unit and cardiovascular intensive care unit between 2014 and 2018 utilizing patient charts and transport records. Multivariate linear and logistic regression analyses adjusted for age, diagnosis, mode of transport, response time, stabilization time, return duration, mortality risk (pediatric index of mortality-2 and pediatric risk of mortality-3), and inotrope, vasopressor, or mechanical ventilation presence on admission.ResultsFour hundred and twenty-eight (50.9%) patients were transported by helicopter, and 413 (49.1%) were transported by ambulance. Physicians accompanied 239 (28.4%) transports. The median response time was 2.0 (interquartile range 1.4-2.9) hours. Although physician presence increased the median response time by 0.26 hours (P = 0.020), neither physician presence nor response time significantly affected mortality, ICU length of stay (ILOS) or hospital length of stay (HLOS). Helicopter transports were not significantly associated with mortality or ILOS, but were associated with a longer HLOS (3.24 days, 95% confidence interval 0.59-5.90) than ambulance transports (P = 0.017).ConclusionsThese results suggest response time and physician presence do not significantly affect mortality or LOS. This may reflect the quality of pre-transport care and medical control communication. Helicopter transports were only associated with a longer HLOS. Our analysis provides a framework for examining transport workforce needs and associated costs

Generation of Laminar Vortex Rings by an Impulsive Body Force

It is shown that laminar vortex rings can be generated by impulsive body forces having particular spatial and temporal characteristics. The method produces vortex rings in a fluid initially at rest, and once generated, the flow field automatically satisfies the boundary conditions and is divergence-free. Numerical simulations and analytical models show that the strength of these rings can be accurately predicted by considering diffusion alone, despite the nonlinear nature of the generation process. A particularly simple model, which approximates the source of vorticity within vertical slabs, is proposed. This model predicts the ring circulation almost as accurately as a model which uses the exact geometry of the source of vorticity. It is found that when the duration of the force is less than a time scale based on the force radius and fluid viscosity, the ring circulation can be predicted accurately using an inviscid model.Comment: 37 pages, 11 figure

Geographic disparities in the risk of perforated appendicitis among children in Ohio: 2001–2003

<p>Abstract</p> <p>Background</p> <p>Rural-urban disparities in health and healthcare are often attributed to differences in geographic access to care and health seeking behavior. Less is known about the differences between rural locations in health care seeking and outcomes. This study examines how commuting patterns in different rural areas are associated with perforated appendicitis.</p> <p>Results</p> <p>Controlling for age, sex, insurance type, comorbid conditions, socioeconomic status, appendectomy rates, hospital type, and hospital location, we found that patient residence in a rural ZIP code with significant levels of commuting to metropolitan areas was associated with higher risk of perforation compared to residence in rural areas with commuting to smaller urban clusters. The former group was more likely to seek care in an urbanized area, and was more likely to receive care in a Children's Hospital.</p> <p>Conclusion</p> <p>To our knowledge, this is the first study to differentiate rural dwellers with respect to outcomes associated with appendicitis as opposed to simply comparing "rural" to "urban". Risk of perforated appendicitis associated with commuting patterns is larger than that posed by several individual indicators including some age-sex cohort effects. Future studies linking the activity spaces of rural dwellers to individual patterns of seeking care will further our understanding of perforated appendicitis and ambulatory care sensitive conditions in general.</p

Medical Transport of Children with Complex Chronic Conditions

One of the most notable trends in child health has been the increase in the number of children with special health care needs, including those with complex chronic conditions. Care of these children accounts for a growing fraction of health care resources. We examine recent developments in health care, especially with regard to medical transport and prehospital care, that have emerged to adapt to this remarkable demographic trend. One such development is the focus on care coordination, including the dissemination of the patient-centered medical home concept. In the prehospital setting, the need for greater coordination has catalyzed the development of the emergency information form. Training programs for prehospital providers now incorporate specific modules for children with complex conditions. Another notable trend is the shift to a family-centered model of care. We explore efforts toward regionalization of care, including the development of specialized pediatric transport teams, and conclude with recommendations for a research agenda

Cosmology and Astrophysics from Relaxed Galaxy Clusters II: Cosmological Constraints

We present cosmological constraints from measurements of the gas mass fraction, $f_{gas}$, for massive, dynamically relaxed galaxy clusters. Our data set consists of Chandra observations of 40 such clusters, identified in a comprehensive search of the Chandra archive, as well as high-quality weak gravitational lensing data for a subset of these clusters. Incorporating a robust gravitational lensing calibration of the X-ray mass estimates, and restricting our measurements to the most self-similar and accurately measured regions of clusters, significantly reduces systematic uncertainties compared to previous work. Our data for the first time constrain the intrinsic scatter in $f_{gas}$, $(7.4\pm2.3)$% in a spherical shell at radii 0.8-1.2 $r_{2500}$, consistent with the expected variation in gas depletion and non-thermal pressure for relaxed clusters. From the lowest-redshift data in our sample we obtain a constraint on a combination of the Hubble parameter and cosmic baryon fraction, $h^{3/2}\Omega_b/\Omega_m=0.089\pm0.012$, that is insensitive to the nature of dark energy. Combined with standard priors on $h$ and $\Omega_b h^2$, this provides a tight constraint on the cosmic matter density, $\Omega_m=0.27\pm0.04$, which is similarly insensitive to dark energy. Using the entire cluster sample, extending to $z>1$, we obtain consistent results for $\Omega_m$ and interesting constraints on dark energy: $\Omega_\Lambda=0.65^{+0.17}_{-0.22}$ for non-flat $\Lambda$CDM models, and $w=-0.98\pm0.26$ for flat constant-$w$ models. Our results are both competitive and consistent with those from recent CMB, SNIa and BAO data. We present constraints on models of evolving dark energy from the combination of $f_{gas}$ data with these external data sets, and comment on the possibilities for improved $f_{gas}$ constraints using current and next-generation X-ray observatories and lensing data. (Abridged)Comment: 25 pages, 14 figures, 8 tables. Accepted by MNRAS. Code and data can be downloaded from http://www.slac.stanford.edu/~amantz/work/fgas14/ . v2: minor fix to table 1, updated bibliograph

The Replication of Bacteriophage MS2: IX. Structure and Replication of the Replicative Intermediate

Experiments are described to determine whether the ribonuclease-sensitive component of the replicative intermediate formed during RNA bacteriophage infection is the nascent strand (conservative replication), or is a displaced portion of the viral strand of the RNA duplex (semi-conservative replication). Appropriate labeling experiments indicate that this component arises in each replicative intermediate molecule, with equal probability, from either origin. Those replicative intermediate molecules in which the nascent strand is ribonuclease-sensitive are more readily denatured than those in which the viral strand is partially displaced. The two types of replicative intermediate can be distinguished on this basis. It is proposed that each replicative intermediate molecule replicates both conservatively and semi-conservatively, equally often