Assessing the utility of SoilGrids250 for biogeographic inference of plant populations.

Inclusion of edaphic conditions in biogeographical studies typically provides a better fit and deeper understanding of plant distributions. Increased reliance on soil data calls for easily accessible data layers providing continuous soil predictions worldwide. Although SoilGrids provides a potentially useful source of predicted soil data for biogeographic applications, its accuracy for estimating the soil characteristics experienced by individuals in small-scale populations is unclear. We used a biogeographic sampling approach to obtain soil samples from 212 sites across the midwestern and eastern United States, sampling only at sites where there was a population of one of the 22 species in Lobelia sect. Lobelia. We analyzed six physical and chemical characteristics in our samples and compared them with predicted values from SoilGrids. Across all sites and species, soil texture variables (clay, silt, sand) were better predicted by SoilGrids (R 2: .25-.46) than were soil chemistry variables (carbon and nitrogen, R 2 ≤ .01; pH, R 2: .19). While SoilGrids predictions rarely matched actual field values for any variable, we were able to recover qualitative patterns relating species means and population-level plant characteristics to soil texture and pH. Rank order of species mean values from SoilGrids and direct measures were much more consistent for soil texture (Spearman r S = .74-.84; all p < .0001) and pH (r S = .61, p = .002) than for carbon and nitrogen (p > .35). Within the species L. siphilitica, a significant association, known from field measurements, between soil texture and population sex ratios could be detected using SoilGrids data, but only with large numbers of sites. Our results suggest that modeled soil texture values can be used with caution in biogeographic applications, such as species distribution modeling, but that soil carbon and nitrogen contents are currently unreliable, at least in the region studied here.

Computational homogenisation based extraction of transverse tensile cohesive responses of cortical bone tissue.

The numerical assessment of fracture properties of cortical bone is important in providing suggestions on patient-specific clinical treatments. We present a generic finite element modelling framework incorporating computational fracture approaches and computational homogenisation techniques. Finite element computations for statistical volume elements (SVEs) at the microscale are performed for different sizes with random osteon packing with a fixed volume fraction. These SVEs are loaded in the transverse direction under tension. The minimal SVE size in terms of ensuring a representative effective cohesive law is suggested to be 0.6 mm. Since cement lines as weak interfaces play a key role in bone fracture, the effects of their fracture properties on the effective fracture strength and toughness are investigated. The extracted effective fracture properties can be used as homogenised inputs to a discrete crack simulation at macroscopic or structural scale. The extrinsic toughening mechanisms observed in the SVE models are discussed with a comparison against experimental observations from the literature, giving beneficial insights to cortical bone failure.

Cumulative Incidence of Revision for a Balanced Knee System at a Mean 8-Year Follow-Up: A Retrospective Review of 500 Consecutive Total Knee Arthroplasties.

PURPOSE: The primary purpose of this study was to evaluate mid-term survival of a Balanced Knee System in the first 500 total knee arthroplasty (TKA) cases using a fully cemented, posterior stabilized TKA at a high-volume private practice. PATIENTS AND METHODS: In this IRB approved retrospective cohort study, data were extracted from a surgical registry at a high-volume orthopaedic practice for the first 500 total knee arthroplasty (TKA) cases performed using the Balanced Knee® System (BKS, Ortho Development®, Draper, Utah, USA). Procedures were performed between June 2000 and September 2003 by one of two orthopaedic surgeons. Follow-up was performed at 6 weeks, 6 months, 1 year, 5 years, and 10 years. 48 patients (9.6%) were considered lost to follow-up. A competing risk analysis was performed to evaluate the cumulative incidence of revision while accounting for the competing risk of death. In the model, failure was defined as revision of any BKS component. Those who failed prior to two years remained in the analysis. RESULTS: The mean age of the population was 69 years (range: 40-94) and 73% were female. The cumulative incidence of revision of any component was approximately 1% at a mean 8-year follow-up (range: 0.11-14.1 years) when accounting for the competing risk of death. When considering all those lost to follow-up as failures, the cumulative incidence of failure at 8 years was approximately 10%. CONCLUSION: Based on the results of the current study, a posterior stabilized primary TKA, implanted using a flexion and extension gap balancing technique, had excellent survivorship and outcomes at a mean 8-year follow-up.

Contracting to improve your revenue cycle performance.

The following key drivers of commercial contract variability can have a material effect on your hospital's revenue cycle: Claim form variance. Benefit design. Contract complexity. Coding variance. Medical necessity. Precertification/authorization. Claim adjudication/appeal requirements. Additional documentation requirements. Timeliness of payment. Third-party payer activity.

Getting on the soapbox: views of an innovator in consumer-directed care.

Consumer-directed health care (CDHC) is often thought of solely as a demand-side solution to the health care cost crisis. One could argue that CDHC is a financing and service revolution that seeks to develop more-efficient financial services products with consumer information to bring about market-based changes in the U.S. health care system. Developing a balanced review of CDHC's potential will help construct future implementations of consumer-directed products and services and advance policy recommendations that improve the cost and quality of health care services.