Order-Disorder Transitions in (Ca_{x}Sr_{1-x})_{3}Rh_{4}Sn_{13}.

The classification of structural phase transitions as displacive or order-disorder in character is usually based on spectroscopic data above the transition. We use single crystal x-ray diffraction to investigate structural correlations in the quasiskutterudites, (Ca_{x}Sr_{1-x})_{3}Rh_{4}Sn_{13}, which have a quantum phase transition at x∼0.9.

A Fast Algorithm for Maximum Likelihood Estimation of Mixture Proportions Using Sequential Quadratic Programming.

≈ 10 ≈ 10 https://CRAN.R-project.org/package=mixsqp).

Bounding the electrostatic free energies associated with linear continuum models of molecular solvation.

The importance of electrostatic interactions in molecular biology has driven extensive research toward the development of accurate and efficient theoretical and computational models. Linear continuum electrostatic theory has been surprisingly successful, but the computational costs associated with solving the associated partial differential equations (PDEs) preclude the theory's use in most dynamical simulations. Modern generalized-Born models for electrostatics can reproduce PDE-based calculations to within a few percent and are extremely computationally efficient but do not always faithfully reproduce interactions between chemical groups.

Quasicontinuum-like reduction of density functional theory calculations of nanostructures.

Density functional theory can accurately predict chemical and mechanical properties of nanostructures, although at a high computational cost. A quasicontinuum-like framework is proposed to substantially increase the size of the nanostructures accessible to simulation. It takes advantage of the near periodicity of the atomic positions in some regions of nanocrystalline materials to establish an interpolation scheme for the electronic density in the system.