Search

Functional overlap among species (redundancy) is considered important in shaping competitive and mutualistic interactions that determine how communities respond to environmental change. Most studies view functional redundancy as static, yet traits within species—which ultimately shape functional redundancy—can vary over seasonal or spatial gradients. We therefore have limited understanding of how trait turnover within and between species could lead to changes in functional redundancy or how loss of traits could differentially impact mutualistic interactions depending on where and when the interactions occur in space and time. Using an Arctic bumblebee community as a case study, and 1277 individual measures from 14 species over three annual seasons, we quantified how inter- and intraspecific body-size turnover compared to species turnover with elevation and over the season. Coupling every individual and their trait with a plant visitation, we investigated how grouping individuals by a morphological trait or by species identity altered our assessment of network structure and how this differed in space and time. Finally, we tested how the sensitivity of the network in space and time differed when simulating extinction of nodes representing either morphological trait similarity or traditional species groups. This allowed us to explore the degree to which trait-based groups increase or decrease interaction redundancy relative to species-based nodes. We found that (i) groups of taxonomically and morphologically similar bees turn over in space and time independently from each other, with trait turnover being larger over the season; (ii) networks composed of nodes representing species versus morphologically similar bees were structured differently; and (iii) simulated loss of bee trait groups caused faster coextinction of bumblebee species and flowering plants than when bee taxonomic groups were lost. Crucially, the magnitude of these effects varied in space and time, highlighting the importance of considering spatiotemporal context when studying the relative importance of taxonomic and trait contributions to interaction network architecture. Our finding that functional redundancy varies spatiotemporally demonstrates how considering the traits of individuals within networks is needed to understand the impacts of environmental variation and extinction on ecosystem functioning and resilience. Read the free Plain Language Summary for this article on the Journal blog.

© 2019 American Society for Surgery of the Hand Purpose: Current evidence on predictors of outcomes after distal radius fracture is often based on retrospective analyses or may be confounded by fracture type. Using data from the Wrist and Radius Injury Surgical Trial (WRIST), a 24-site randomized study of distal radius fracture treatment, in which all fractures are severe enough to warrant surgery, we set out to perform a secondary data analysis to explore predictors of better or worse hand outcomes. Methods: The primary outcome measure was the Michigan Hand Outcomes Questionnaire (MHQ) summary score 12 months after treatment. We used a regression tree analysis with recursive partitioning to identify subgroups of participants who experienced similar outcomes (ie, MHQ score) and to determine which baseline or treatment factors they had in common. Results: Factors most predictive of 12-month MHQ score were pain at enrollment, education, age, and number of comorbidities. Specifically, participants who had a high school education or less and also reported severe pain had the lowest MHQ scores. Conversely, participants with less pain and more education and who were age 87 years or younger with one or no comorbid condition had the highest MHQ scores. Treatment type or radiographic measurements assessed on post-reduction films did not affect 12-month outcomes. Conclusions: These results identified patient characteristics that can be used by surgeons to identify subgroups of patients who may experience similar hand outcomes. Type of study/level of evidence: Prognostic III.

Launching is a bridge erection method that provides significant advantages when there is difficult underdeck access for falsework, crane and heavy plant. In such cases, assembling the deck in a more accessible position and launching it over the piers may mean a significant saving of resources. In some cases access is simply not possible due to other constraints, for example over environmentally protected areas. This is the case of the north approach viaduct of the new Queensferry Crossing, a major cable-stayed bridge over the Firth of Forth in Scotland, UK. This paper provides a description of the approach viaduct north and its launch process. This viaduct is a single/twin-girder bridge with composite section and two spans of 101·5 m and 104 m. Owing to its particular characteristics and impressive launch weight of 6200 t, the launching process has not been conventional, and particular solutions have been used and combined to ensure full compliance with the strict design constraints. The assembly process was not conventional either, owing to space constraints and the weight and size of the pieces.

Natural enemies of plants have the potential to influence the dynamics of plant populations and the structure of plant communities. In diverse tropical forests, research on the effects of plant enemies has largely focused on the diversity‐enhancing effects of highly specialized enemies, while the community‐level effects of enemies with broader diets have rarely been considered. We investigated the community of insect seed predators interacting with seven tree species in the family Lauraceae on Barro Colorado Island (Panama). We present one of the first quantitative food webs for pre‐dispersal insect seed predators and their host plants, and use the information in the web to assess the potential for indirect interactions between the tree species. Our data suggest that there is high potential for indirect interactions between Lauraceae species via their shared seed predators. The strength and direction of these interactions are largely unrelated to the phylogenetic distance and trait similarity between species but are likely governed by the volume of fruit produced by each tree species.

Purpose To evaluate the clinical and radiographic outcomes of patients who underwent semiconstrained distal radioulnar joint arthroplasty Methods A retrospective analysis was performed on a series of patients who underwent distal radioulnar joint arthroplasty with more than a 23-month follow up. The quantitative outcome variables included the visual analog scale for pain; Disability of the Arm, Shoulder, and Hand (DASH) score; Patient-Rated Wrist Evaluation (PRWE); and Mayo wrist score. The range of motion, grip strength, torque, and lifting capacity were measured at final follow up and compared with that of the nonsurgical extremity. Complications related to the prosthesis were assessed. Results Twenty-one patients (mean age 57 years) were assessed at an average 41-month follow up (23–73 months). Fifteen underwent prior hand, wrist, or elbow procedures. Four patients required 5 reoperations . The postoperative median visual analog scale pain score was 0.6 at rest and 2.1 with activity. The median postoperative DASH score was 26.7, PRWE 41, and Mayo wrist score was 65. Upon comparing the supination torque of the operative and intact sides, the operative side was found to average 87% of the intact side on a work simulator and 77% on the simulator’s D-ring. Eight of 20 patients had lysis around the collar of the ulnar component (40%), as detected using radiography. Three of 21 (14%) radial plates were malpositioned, with 2 resulting in a fracture. The overall complication rate was 29%. Conclusions Distal radioulnar joint arthroplasty using the Scheker prosthesis demonstrated good patient pain scores and the restoration of supination strength. The collar lysis resulted in weaker supination and grip strength. Still, the patients experienced mild levels of pain and moderate disability. A moderate complication rate persisted, as reported by other authors. Accurate radial component placement is important. Type of study/level of evidence Therapeutic IV.

Review editor's note: This review by Alan Ward is being published posthumously. It was completed only a few weeks before he passed away in December 2014. Peter Hempenstall has observed in an obitua...

In the context of high-altitude mountain ridges, harvesting energy with wind turbines presents new challenges. The results of a computer model solving the Reynolds-Averaged Navier–Stokes equations for incompressible flows above such a ridge are presented in the context of a case study. A theoretical blade-element model of a triblade Horizontal-Axis Wind Turbine (HAWT) was implemented. By combining both models we show that a wind turbine placed at such a location may receive less dense incoming air with repercussions on power output, as well as other unforeseen effects due to airflow negative vertical incidence such as the appearance of harmonic cyclic torque both in the turbine main shaft and nacelle yaw-control system.

Correlation of long-term temperature variability and population density was investigated in an isolated mountain environment case study for the sixteenth to eighteenth centuries period. Andorra (Central Pyrenees) was chosen as a case study location due to its harsh environmental conditions and to its historical politically neutral position. Reconstructed temperatures for the eighteenth century, based on dendrochronological data, show strong statistical correlations with death inventories (rs = −0.359, p