Continent-wide tree fecundity driven by indirect climate effects.

Indirect climate effects on tree fecundity that come through variation in size and growth (climate-condition interactions) are not currently part of models used to predict future forests. Trends in species abundances predicted from meta-analyses and species distribution models will be misleading if they depend on the conditions of individuals. Here we find from a synthesis of tree species in North America that climate-condition interactions dominate responses through two pathways, i) effects of growth that depend on climate, and ii) effects of climate that depend on tree size. Because tree fecundity first increases and then declines with size, climate change that stimulates growth promotes a shift of small trees to more fecund sizes, but the opposite can be true for large sizes. Change the depresses growth also affects fecundity. We find a biogeographic divide, with these interactions reducing fecundity in the West and increasing it in the East. Continental-scale responses of these forests are thus driven largely by indirect effects, recommending management for climate change that considers multiple demographic rates.

Accuracy of Component Positioning in 1980 Total Hip Arthroplasties: A Comparative Analysis by Surgical Technique and Mode of Guidance.

The purpose of this multi-surgeon study was to assess and compare the accuracy of acetabular component placement, leg length discrepancy (LLD), and global offset difference (GOD) between six different surgical techniques and modes of guidance in total hip arthroplasty (THA). A total of 1980 THAs met inclusion criteria. Robotic- and navigation-guided techniques were more consistent than other techniques in placing the acetabular cup into Lewinnek's safe zone (P<0.005 and P<0.05, respectively). Robotic-guided surgery was more consistent than other techniques in placing the acetabular component within Callanan's safe zone (P<0.005). No statistically significant differences were found between groups in the frequency of patients with excessive LLD. Clinically significant differences between groups were not found in the frequency of patients with excessive GOD. Level of Evidence: IV.

Hip Arthroplasty or Medical Management: A Challenging Treatment Decision for Younger Patients.

The two main treatment options for total hip arthroplasty (THA), medical management and surgical intervention, have advantages and disadvantages, creating a challenging decision. Treatment decisions are further complicated in a younger population (≤50) as the potential need for revision surgery is probable. We examined the relationship of selected variables to the decision-making process for younger patients with symptomatic OA. Thirty-five participants chose surgical intervention and 36 selected medical management for their current treatment. Pain, activity restrictions, and total WOMAC scores were statistically significant (P < .05) for patients selecting surgical intervention. No difference in quality of life was shown between groups. Pain was the only predictor variable identified, however, activity restrictions were also influential variables as these were highly correlated with pain.

Factors influencing hydride formation in a Pd/TiO2 catalyst.

A sample containing Pd nanoparticles deposited on TiO(2) was subjected to a series of different thermal pretreatments. The range of these treatments was selected to provide a palladium surface in a number of different states, including a form where TiO(x) overlayers had been formed. Experiments were conducted to determine how the state of the Pd surface influenced the formation of Pd hydride. The amount of hydrogen released during a temperature-programmed experiment was used to quantify the extent of Pd beta-hydride formation following room-temperature exposure to hydrogen. Samples were characterized by HAADF (high-angle annular dark-field) electron microscopy with EDX (energy-dispersive X-ray) analysis and CO pulse chemisorption and FTIR (Fourier transform infrared spectroscopy) of adsorbed CO. The amount and the ease with which Pd beta-hydride was formed was found to be dependent on the metal surface area, the presence of titania overlayers, and the Pd surface roughness/defect concentration.