Spatiotemporal thermal variation drives diversity trends in experimental landscapes.

Temperature is a fundamental driver of species' vital rates and thus coexistence, extinctions and community composition. While temperature is neither static in space nor in time, little work has incorporated spatiotemporal dynamics into community-level investigations of thermal variation. We conducted a microcosm experiment using ciliate protozoa to test the effects of temperatures fluctuating synchronously or asynchronously on communities in two-patch landscapes connected by short or long corridors. We monitored the abundance of each species for 4 weeks-equivalent to ~28 generations-measuring the effects of four temperature regimes and two corridor lengths on community diversity and composition. While corridor length significantly altered the trajectory of diversity change in the communities, this did not result in different community structures at the end of the experiment. The type of thermal variation significantly affected both the temporal dynamics of diversity change and final community composition, with synchronous fluctuation causing deterministic extinctions that were consistent across replicates and spatial variation causing the greatest diversity declines. Our results suggest that the presence and type of thermal variation can play an important role in structuring ecological communities, especially when it interacts with dispersal between habitat patches.

Analysis of the infra-acetabular corridor: sex-specific differences in the secure area and insertion angle in infra-acetabular screw placement.

OBJECTIVES: A majority of older adult acetabular fracture patients have a fracture of the anterior component, and repair of the acetabular anterior component with infra-acetabular screw (IAS) fixation is crucial. The aim of this study was to clarify the sex-specific differences in the secure infra-acetabular corridor for safe IAS placement. METHODS: Three-dimensional pelvic computed tomography (CT) images of 50 males and 50 females with an average age of 77.5 years were analyzed. The secure insertion path of IAS was simulated on the ZedHip system (Lexi Co., Ltd., Japan), and length, angle, and diameters of the infra-acetabular corridor were measured. RESULTS: The lengths of the corridors were 99.0±4.6 mm in males and 91.5±5.3 mm in females (p<0.01). The angle of the corridor to Y axis in the axial plane on the functional pelvic plane (FPP) was 5.1±4.9° in males and 8.6±5.3° in females (p<0.01). However, in 32% of the cases it was deemed that a IAS could not be inserted because the diameters of the corridor were too narrow to insert the screw. CONCLUSIONS: On simulation, the corridor length was shorter and corridor angle was larger in females. In one third of cases the infra-acetabular corridor simulation showed it was impossible to insert the IAS, so it is crucial to scrutinize the infra-acetabular corridor on CT images during preoperative planning for IAS insertion in acetabular fractures.