Eliminating artificial boundary conditions in time-dependent density functional theory using Fourier contour deformation

We present an efficient method for propagating the time-dependent Kohn-Sham equations in free space, based on the recently introduced Fourier contour deformation (FCD) approach. For potentials which are constant outside a bounded domain, FCD yields a high-order accurate numerical solution of the time-dependent Schrodinger equation directly in free space, without the need for artificial boundary conditions. Of the many existing artificial boundary condition schemes, FCD is most similar to an exact nonlocal transparent boundary condition, but it works directly on Cartesian grids in any dimension, and runs on top of the fast Fourier transform rather than fast algorithms for the application of nonlocal history integral operators. We adapt FCD to time-dependent density functional theory (TDDFT), and describe a simple algorithm to smoothly and automatically truncate long-range Coulomb-like potentials to a time-dependent constant outside of a bounded domain of interest, so that FCD can be used. This approach eliminates errors originating from the use of artificial boundary conditions, leaving only the error of the potential truncation, which is controlled and can be systematically reduced. The method enables accurate simulations of ultrastrong nonlinear electronic processes in molecular complexes in which the inteference between bound and continuum states is of paramount importance. We demonstrate results for many-electron TDDFT calculations of absorption and strong field photoelectron spectra for one and two-dimensional models, and observe a significant reduction in the size of the computational domain required to achieve high quality results, as compared with the popular method of complex absorbing potentials

Admission Requirements and Practices in Entry-Level Occupational Therapy Programs

When establishing admission processes for entry-level doctoral programs, admission requirements for master-level programs provide a comparison for consideration. The purpose of this study was to provide information about admission practices for graduate-level occupational therapy programs. The three aims included: 1) to describe admission requirements of a sample of entry-level master’s programs; 2) to examine the relationship between attrition and admission requirements for the sample; and 3) to provide a summary of admission requirements used by entry-level master and doctoral programs in the United States. Results of the study provided a synthesis of information about admission requirements that included programs’ minimum pre-admission grade point average, Graduate Record Examination (GRE) requirements, and interview processes (e.g., format, time, personnel). A review of the websites for 172 entry-level master’s and doctoral programs across the United States provided a comprehensive description of national admission requirements. Results of a survey of 31 master’s level programs provided information on student demographics (e.g., race/ethnicity, gender), admission requirements, and attrition information for the cohorts admitted in a single year. Survey results also examined the relationship between attrition and admission requirements. Educational programs have opportunities, responsibilities, and challenges associated with the selection of the most qualified applicants to meet academic and professional behavior standards. Periodic examination of admission processes within and across occupational therapy education programs is important for the integrity of the profession

Promoting Self-Management of Breast Cancer-Related Lymphedema Through the Remotivation Process

Background. Lymphedema affects a significant number of women with breast cancer. Self-Management Programs (SMP) are important in the long-term management of chronic conditions such as lymphedema. Motivation is crucial in the daily performance of the SMP. The study explored the effect of the Remotivation Process on the motivation of women with breast cancer-related lymphedema to incorporate an SMP into their daily routine. Methodology. The study was a within-subjects quasi-experimental design that used the Volitional Questionnaire, frequency count of the SMP, and circumferential measurement as outcome measures. Eleven participants (n = 11) with breast cancer-related lymphedema completed the study that used the Remotivation Process as the intervention for 4 weeks with a follow-up session during the 8th week. Results. The participants progressed to a higher state of motivation on the Volitional Questionnaire at the end of the study. There was an increase in the performance of the exercise component of the SMP in 7 days, and a significant decrease in the circumferential measurement of the affected arm. There was also a positive correlation between VQ and circumferential measurements. Conclusion. The study suggests the usefulness of the Remotivation Process in an occupational therapy intervention to promote self-management. It can possibly facilitate motivation, improvement in the manifestation of lymphedema, and the daily performance of the self-management program for lymphedema

Planet Hunters TESS III: Two transiting planets around the bright G dwarf HD 152843

We report on the discovery and validation of a two-planet system around a bright (V = 8.85 mag) early G dwarf (1.43 $R_{\odot}$, 1.15 $M_{\odot}$, TOI 2319) using data from NASA's Transiting Exoplanet Survey Satellite (TESS). Three transit events from two planets were detected by citizen scientists in the month-long TESS light curve (sector 25), as part of the Planet Hunters TESS project. Modelling of the transits yields an orbital period of \Pb\ and radius of $3.41 _{ - 0.12 } ^ { + 0.14 }$ $R_{\oplus}$ for the inner planet, and a period in the range 19.26-35 days and a radius of $5.83 _{ - 0.14 } ^ { + 0.14 }$ $R_{\oplus}$ for the outer planet, which was only seen to transit once. Each signal was independently statistically validated, taking into consideration the TESS light curve as well as the ground-based spectroscopic follow-up observations. Radial velocities from HARPS-N and EXPRES yield a tentative detection of planet b, whose mass we estimate to be $11.56 _{ - 6.14 } ^ { + 6.58 }$ $M_{\oplus}$, and allow us to place an upper limit of $27.5$ $M_{\oplus}$ (99 per cent confidence) on the mass of planet c. Due to the brightness of the host star and the strong likelihood of an extended H/He atmosphere on both planets, this system offers excellent prospects for atmospheric characterisation and comparative planetology

Eliminating Artificial Boundary Conditions in Time-Dependent Density Functional Theory Using Fourier Contour Deformation

We present an efficient method for propagating the time-dependent Kohn-Sham equations in free space, based on the recently introduced Fourier contour deformation (FCD) approach. For potentials which are constant outside a bounded domain, FCD yields a high-order accurate numerical solution of the time-dependent Schrödinger equation directly in free space, without the need for artificial boundary conditions. Of the many existing artificial boundary condition schemes, FCD is most similar to an exact nonlocal transparent boundary condition, but it works directly on Cartesian grids in any dimension, and runs on top of the fast Fourier transform rather than fast algorithms for the application of nonlocal history integral operators. We adapt FCD to time-dependent density functional theory (TDDFT), and describe a simple algorithm to smoothly and automatically truncate long-range Coulomb-like potentials to a time-dependent constant outside of a bounded domain of interest, so that FCD can be used. This approach eliminates errors originating from the use of artificial boundary conditions, leaving only the error of the potential truncation, which is controlled and can be systematically reduced. The method enables accurate simulations of ultrastrong nonlinear electronic processes in molecular complexes in which the interference between bound and continuum states is of paramount importance. We demonstrate results for many-electron TDDFT calculations of absorption and strong field photoelectron spectra for one and two-dimensional models, and observe a significant reduction in the size of the computational domain required to achieve high quality results, as compared with the popular method of complex absorbing potentials