Modeling lake conductivity in the contiguous United States using spatial indexing for big spatial data.

Conductivity is an important indicator of the health of aquatic ecosystems. We model large amounts of lake conductivity data collected as part of the United States Environmental Protection Agency's National Lakes Assessment using spatial indexing, a flexible and efficient approach to fitting spatial statistical models to big data sets. Spatial indexing is capable of accommodating various spatial covariance structures as well as features like random effects, geometric anisotropy, partition factors, and non-Euclidean topologies.

Structures and ammonia synthesis activity of hexagonal ruthenium iron nitride phases.

A series of ruthenium iron nitride phases with Ru:Fe ratios of ca. 1:3 were synthesized by ammonolysis. When the ammonolysis temperature was above 500°C, the obtained RuFeN materials had a ε-FeN (622) structure, while two similar phases were present when the ammonolysis was lower than 500°C.

Multiscale Investigation of the Mechanism and Selectivity of CO Hydrogenation over Rh(111).

CO hydrogenation over Rh catalysts comprises multiple reaction pathways, presenting a wide range of possible intermediates and end products, with selectivity toward either CO or methane being of particular interest. We investigate in detail the reaction mechanism of CO hydrogenation to the single-carbon (C1) products on the Rh(111) facet by performing periodic density functional theory (DFT) calculations and kinetic Monte Carlo (kMC) simulations, which account for the adsorbate interactions through a cluster expansion approach. We observe that Rh readily facilitates the dissociation of hydrogen, thus contributing to the subsequent hydrogenation processes.

Exploring the relationship of supernumerary recurrent renal calculi formation and tick-borne infections: a case report.

A 51-year-old male with a history of Cacchi-Ricci disease and long-standing infection with various species of presented with recurrent symptoms of right-sided flank pain. Numerous renal calculi were identified on imaging. The etiology of the calculi had not been previously elucidated.