Descriptive Analysis of Orthopaedic Surgery Residency Program Directors.

The purpose of this study was to analyze the demographics and backgrounds of U.S. orthopaedic surgery residency program directors (PDs).

Periodic Coulomb Tree Method: An Alternative to Parallel Particle Mesh Ewald.

Particle mesh Ewald (PME) is generally the method of choice for handling electrostatics in simulations with periodic boundary conditions. The excellent efficiency of PME on low processor counts is largely due to the use of the fast Fourier transform (FFT). However, due to the FFT's high communication cost, PME scales poorly in parallel.

Advanced Potential Energy Surfaces for Molecular Simulation.

Advanced potential energy surfaces are defined as theoretical models that explicitly include many-body effects that transcend the standard fixed-charge, pairwise-additive paradigm typically used in molecular simulation. However, several factors relating to their software implementation have precluded their widespread use in condensed-phase simulations: the computational cost of the theoretical models, a paucity of approximate models and algorithmic improvements that can ameliorate their cost, underdeveloped interfaces and limited dissemination in computational code bases that are widely used in the computational chemistry community, and software implementations that have not kept pace with modern high-performance computing (HPC) architectures, such as multicore CPUs and modern graphics processing units (GPUs). In this Feature Article we review recent progress made in these areas, including well-defined polarization approximations and new multipole electrostatic formulations, novel methods for solving the mutual polarization equations and increasing the MD time step, combining linear-scaling electronic structure methods with new QM/MM methods that account for mutual polarization between the two regions, and the greatly improved software deployment of these models and methods onto GPU and CPU hardware platforms.

Development of Clostridium septicum gas gangrene as an adverse effect of clindamycin-induced Clostridium difficile infection in a pediatric patient.

Clostridium myonecrosis or gas gangrene is a life-threatening infection characterized by either traumatic or atraumatic etiology. It has been widely described in patients with traumatic open wounds and in immunocompromised patients, including malignancy. A third source can result from natural flora in the gastrointestinal tract after bowel ischemia.

Comparison of treecodes for computing electrostatic potentials in charged particle systems with disjoint targets and sources.

In molecular simulations, it is sometimes necessary to compute the electrostatic potential at M target sites due to a disjoint set of N charged source particles. Direct summation requires O(MN) operations, which is prohibitively expensive when M and N are large. Here, we consider two alternative tree-based methods that reduce the cost.