Puckering Coordinates of Monocyclic Rings by Triangular Decomposition

We describe a new method of describing the pucker of an N-member monocyclic ring using N−3 parameters. To accomplish this, three ring atoms define a reference plane, and the remainder of the ring is decomposed into triangular flaps. The angle of incidence for each flap upon the reference plane is then measured. The combination of these angles is characteristic of the ring\u27s pucker. This puckering coordinate system is compared to existing reduced parameter systems to describe rings using a cyclohexane molecule. We show that this method has the same descriptive power of previous systems while offering advantages in molecular simulations

Long-range correlation energy calculated from coupled atomic response functions

An accurate determination of the electron correlation energy is essential for describing the structure, stability, and function in a wide variety of systems, ranging from gas-phase molecular assemblies to condensed matter and organic/inorganic interfaces. Even small errors in the correlation energy can have a large impact on the description of chemical and physical properties in the systems of interest. In this context, the development of efficient approaches for the accurate calculation of the long-range correlation energy (and hence dispersion) is the main challenge. In the last years a number of methods have been developed to augment density functional approximations via dispersion energy corrections, but most of these approaches ignore the intrinsic many-body nature of correlation effects, leading to inconsistent and sometimes even qualitatively incorrect predictions. Here we build upon the recent many-body dispersion (MBD) framework, which is intimately linked to the random-phase approximation for the correlation energy. We separate the correlation energy into short-range contributions that are modeled by semi-local functionals and long-range contributions that are calculated by mapping the complex all-electron problem onto a set of atomic response functions coupled in the dipole approximation. We propose an effective range-separation of the coupling between the atomic response functions that extends the already broad applicability of the MBD method to non-metallic materials with highly anisotropic responses, such as layered nanostructures. Application to a variety of high-quality benchmark datasets illustrates the accuracy and applicability of the improved MBD approach, which offers the prospect of first-principles modeling of large structurally complex systems with an accurate description of the long-range correlation energy.Comment: 15 pages, 3 figure

Organizational Change: The Experiences of Practitioners Transitioning to a Fee-for-Service Model

Many human service agencies are in the midst of a transition for a fee-for-service model. Through the midst of the transition, organizations must shift the culture of their agency and adapt to the new service delivery approach. Some organizational changes can create feelings of insecurity among staff, fewer resources, and greater potential for employee burnout. Though there is some research that provides valuable information, it often fails to highlight the individual experiences of the worker. This phenomenological study begins to explore the experiences and perceptions of practitioners working in supported housing agencies during the transition to a fee-for-service approach. The researchers utilized two focus groups to collect data and conducted thematic analysis to highlight specific themes to address the benefits and areas of improvements of a fee-for-service model. By understanding the experiences and perspectives from practitioners, other human service providers may have a greater understanding of implications for their practice

Electrodynamic Response and Stability of Molecular Crystals

We show that electrodynamic dipolar interactions, responsible for long-range fluctuations in matter, play a significant role in the stability of molecular crystals. Density functional theory calculations with van der Waals interactions determined from a semilocal "atom-in-a-molecule" model result in a large overestimation of the dielectric constants and sublimation enthalpies for polyacene crystals from naphthalene to pentacene, whereas an accurate treatment of non-local electrodynamic response leads to an agreement with the measured values for both quantities. Our findings suggest that collective response effects play a substantial role not only for optical excitations, but also for cohesive properties of non-covalently bound molecular crystals

Perceptions of Recovery While Delivering Medicaid Covered Rehabilitation Services

Many states have shifted to Medicaid reimbursement methods to cover behavioral health services. In doing so, state mental health authorities have incorporated the concept of recovery into mental health policy. Thus, gaining a better understanding of practitioners’ perceptions of recovery in a new fiscal environment is warranted. This qualitative study explores how New Jersey practitioners transitioning to a new state-wide Medicaid payment structure perceive recovery from mental illness. Four themes emerged following a thematic analysis. Future studies that explore perspectives of individuals receiving services could provide useful information for policy makers, agencies, and community stakeholders

Experimental equilibrium structures of solids and gases

In the past sixty years, X-ray, neutron and electron dffraction have emerged as the structural techniques of choice in the solid state. However, despite many advances in theory and instrumentation, these diffraction methods are still reliant on a number of assumptions. Chief amongst these is that the atoms in the crystal vibrate in a harmonic fashion. This thesis is concerned with understanding the effects of anharmonic motion on crystal structure determination and developing new ways of moving beyond the harmonic approximation used in crystallography. A method has been developed, using molecular dynamics simulations, to correct experimental structures to equilibrium structures. This has been applied to the crystal structures of phase-I deutero-ammonia, deutero-nitromethane and benzophenone. Path-integral molecular dynamics simulations have been used to obtain meaningful comparison with experimental data collected at low temperatures. The simulations also offer information on the probability density functions that describe thermal motion in solids. Using data from simulations of nitromethane and other compounds it has been demonstrated that the molecular dynamics-derived data can be used to assess and develop new functions for modelling thermal motion in crystal structure refinements. Finally, similar molecular dynamics techniques have been applied to determine the equilibrium structures of some polyhedral oligomeric silsesquioxanes in the gas phase. Some members of this class of compounds feature such strong anharmonic motion that refinement of the structures using gas electron diffraction is impossible without taking into account the effects of the anharmonicity

Which Police Departments Make Black Lives Matter, Which Don’t, and Why Don’t Most Social Scientists Care?

In part via skillful use of social media, Black Lives Matter (BLM) has become among the most influential social movements of the past half century, with support across racial lines, and considerable financial backing (Fisher, 2019). Will this translate into public policy reforms which save Black lives? After all, higher education is a key institutional backer of BLM, and a considerable literature dating back decades (e.g., Lindblom & Cohen, 1979) casts doubt on the effectiveness of social science in solving social problems, for numerous reasons. Often, the best social science is simple counting. This paper makes two unique contributions. First, using scholarly citations, we show empirically that social scientists focus far more attention on research regarding BLM related activism than on research regarding how to improve policing in ways that might save Black lives. Second, to encourage more research regarding saving Black lives, we update and enlarge a prior peer reviewed study (Bearfield, Maranto, & Wolf, 2020) which ranks big city police departments by their effectiveness in keeping Black (and non-Black) citizens safe. We conclude with ideas for future research and policy reform. Police commissioners and other policymakers need to be asked the right questions to drive reform and enact better policies to enable reforms to succeed. Currently, social science is failing to contribute much to either