Which Algorithm Best Propagates the Meyer-Miller-Stock-Thoss Mapping Hamiltonian for Non-Adiabatic Dynamics?

A common strategy to simulate mixed quantum-classical dynamics is by propagating classical trajectories with mapping variables, often using the Meyer-Miller-Stock-Thoss (MMST) Hamiltonian or the related spin-mapping approach. When mapping the quantum subsystem, the coupled dynamics reduce to a set of equations of motion to integrate. Several numerical algorithms have been proposed, but a thorough performance comparison appears to be lacking. Here, we compare three time-propagation algorithms for the MMST Hamiltonian: the Momentum Integral (MInt) (J. Chem. Phys., 2018, 148, 102326), the Split-Liouvillian (SL) (Chem. Phys., 2017, 482, 124-134), and the algorithm in J. Chem. Phys., 2012, 136, 084101 that we refer to as the Degenerate Eigenvalue (DE) algorithm due to the approximation required during derivation. We analyze the accuracy of individual trajectories, correlation functions, energy conservation, symplecticity, Liouville's theorem, and the computational cost. We find that the MInt algorithm is the only rigorously symplectic algorithm. However, comparable accuracy at a lower computational cost can be obtained with the SL algorithm. The approximation implicitly made within the DE algorithm conserves energy poorly, even for small timesteps, and thus leads to slightly different results. These results should guide future mapping-variable simulations.

Exploring the development of professional values in an online RN-to-BSN program.

BACKGROUND: Development of professional nursing values is critical within registered nurse-to-bachelor of science in nursing programs to prepare nurses for increasingly complex and diverse work environments. The results of previous studies have been inconsistent, with few studies focusing on online registered nurse-to-bachelor of science in nursing programs. In addition, little is known regarding the effectiveness of the educational methods used to support advancement of professional values and ethical practice. OBJECTIVE: The object of this study was to gain an understanding of nursing students' attitudes and beliefs about professional values at entry and exit of an online registered nurse-to-bachelor of science in nursing program that includes a standalone ethics course and integrates American Nurses Association Code of Ethics provisions throughout the curriculum. RESEARCH DESIGN: For this one-group pretest-posttest, quasi-experimental design, longitudinal matched-pair data were gathered at program entry and exit using the Nurses Professional Values Scale-Revised. PARTICIPANTS AND RESEARCH CONTEXT: In all, 119 students of an online registered nurse-to-bachelor of science in nursing program at a Midwest public university who completed entry and exit surveys between spring 2015 and spring 2018 were included in this study. ETHICAL CONSIDERATIONS: This study was reviewed and determined to be exempt by the university's institutional review board. FINDINGS: The results showed a significant increase in total posttest scores when considering all participants. However, students who took the ethics course after the pretest demonstrated a significant increase in posttest scores, while students who took the ethics course prior to the pretest demonstrated a small increase that was not statistically significant. Significant increases were also found in the professionalism, activism, and trust factors. DISCUSSION: This study supports previous study findings where students scored higher on caring and lower on activism and professionalism factors. The largest gains were made after completing the ethics course. CONCLUSION: The results suggest that requiring a standalone ethics course in the registered nurse-to-bachelor of science in nursing curriculum had a positive impact on self-reported professional values.

Genome Sequence of Acetomicrobium hydrogeniformans OS1.

Acetomicrobium hydrogeniformans, an obligate anaerobe of the phylum Synergistetes, was isolated from oil production water. It has the unusual ability to produce almost 4 molecules H2/molecule glucose. The draft genome of A. hydrogeniformans OS1 (DSM 22491T) is 2,123,925 bp, with 2,068 coding sequences and 60 RNA genes.

Complete genome sequence of Methanospirillum hungatei type strain JF1.

Methanospirillum hungatei strain JF1 (DSM 864) is a methane-producing archaeon and is the type species of the genus Methanospirillum, which belongs to the family Methanospirillaceae within the order Methanomicrobiales. Its genome was selected for sequencing due to its ability to utilize hydrogen and carbon dioxide and/or formate as a sole source of energy. Ecologically, M. hungatei functions as the hydrogen- and/or formate-using partner with many species of syntrophic bacteria. Its morphology is distinct from other methanogens with the ability to form long chains of cells (up to 100 µm in length), which are enclosed within a sheath-like structure, and terminal cells with polar flagella. The genome of M. hungatei strain JF1 is the first completely sequenced genome of the family Methanospirillaceae, and it has a circular genome of 3,544,738 bp containing 3,239 protein coding and 68 RNA genes. The large genome of M. hungatei JF1 suggests the presence of unrecognized biochemical/physiological properties that likely extend to the other Methanospirillaceae and include the ability to form the unusual sheath-like structure and to successfully interact with syntrophic bacteria.