Electronic levels and electrical response of periodic molecular structures from plane-wave orbital-dependent calculations

Plane-wave electronic-structure predictions based upon orbital-dependent density-functional theory (OD-DFT) approximations, such as hybrid density-functional methods and self-interaction density-functional corrections, are severely affected by computational inaccuracies in evaluating electron interactions in the plane-wave representation. These errors arise from divergence singularities in the plane-wave summation of electrostatic and exchange interaction contributions. Auxiliary-function corrections are reciprocal-space countercharge corrections that cancel plane-wave singularities through the addition of an auxiliary function to the point-charge electrostatic kernel that enters into the expression of interaction terms. At variance with real-space countercharge corrections that are employed in the context of density-functional theory (DFT), reciprocal-space corrections are computationally inexpensive, making them suited to more demanding OD-DFT calculations. Nevertheless, there exists much freedom in the choice of auxiliary functions and various definitions result in different levels of performance in eliminating plane-wave inaccuracies. In this work, we derive exact point-charge auxiliary functions for the description of molecular structures of arbitrary translational symmetry, including the yet unaddressed one-dimensional case. In addition, we provide a critical assessment of different reciprocal-space countercharge corrections and demonstrate the improved accuracy of point-charge auxiliary functions in predicting the electronic levels and electrical response of conjugated polymers from plane-wave OD-DFT calculations.Comment: 11 pages, 7 figure

Solving Vlasov Equations Using NRxx Method

In this paper, we propose a moment method to numerically solve the Vlasov equations using the framework of the NRxx method developed in [6, 8, 7] for the Boltzmann equation. Due to the same convection term of the Boltzmann equation and the Vlasov equation, it is very convenient to use the moment expansion in the NRxx method to approximate the distribution function in the Vlasov equations. The moment closure recently presented in [5] is applied to achieve the globally hyperbolicity so that the local well-posedness of the moment system is attained. This makes our simulations using high order moment expansion accessible in the case of the distribution far away from the equilibrium which appears very often in the solution of the Vlasov equations. With the moment expansion of the distribution function, the acceleration in the velocity space results in an ordinary differential system of the macroscopic velocity, thus is easy to be handled. The numerical method we developed can keep both the mass and the momentum conserved. We carry out the simulations of both the Vlasov-Poisson equations and the Vlasov-Poisson-BGK equations to study the linear Landau damping. The numerical convergence is exhibited in terms of the moment number and the spatial grid size, respectively. The variation of discretized energy as well as the dependence of the recurrence time on moment order is investigated. The linear Landau damping is well captured for different wave numbers and collision frequencies. We find that the Landau damping rate linearly and monotonically converges in the spatial grid size. The results are in perfect agreement with the theoretic data in the collisionless case

Chinese Canadian Librarians: Leadership Roles and Career Barriers

Based on the data from the Visible Minority Librarians of Canada Network (ViMLoC) 2021 Survey, this research examined the leadership roles held by Chinese Canadian librarians and their perceptions of inclusivity of work climate, job satisfaction, and race as a career barrier. Their encounters with racial microaggressions and mentorship experience were also explored. Of the 38 respondents, 79% (n=30) were in non-management positions. 82% (n=31) felt very satisfied or satisfied with their jobs; however, their work climate was not found to be inclusive to all respondents. 87% (n=33) indicated that race was a barrier to their career. Fisher’s exact tests were run to compare the management group and non-management group. The results showed that those in management positions were less satisfied with their jobs and less likely to feel free to express their views openly. They experienced various forms of racial microaggressions. Nearly half of the respondents sought mentoring support and two-thirds of them found mentorship extremely helpful or very helpful. To increase representation in librarianship, library school students and first-generation immigrants of Chinese descent need to be inspired to enter librarianship and reach higher professional goals. Chinese librarians would benefit from leadership programs tailored to minority librarians in Canada

Sources of COVID-19 Information Seeking and their Associations with Self-Perceived Mental Health among Canadians

Using two datasets from the Canadian Perspectives Survey Series (CPSS), this study provides a longitudinal analysis of information sources Canadians consulted regarding COVID-19 and their associations with poor self-perceived mental health (SPMH) during March and July 2020. Nearly 20% of Canadians who were surveyed reported poor SPMH. The logistic regression results revealed that at Time 2 (July 2020), after controlling for demographic, socio-economic, and psychobehavioural factors, using social media was significantly associated with higher odds of poor SPMH than using six other information sources including news outlets, federal health agencies, provincial health agencies, provincial daily announcements, places of employment, and other sources (for example, schools, colleges, universities). Checking the accuracy of online information more frequently was also associated with lower odds of poor SPMH

Racial Pay Gap: An Analysis of CARL Libraries

Using data from the 8Rs CARL Libraries Practitioner Survey in 2014, this study assesses the impact of race on the earnings attainment process based on a sample of 392 CARL library practitioners. It determines that there is a significant salary disparity between visible minorities and non-visible minorities. Racial differences in job characteristics account for a larger portion of the explained racial salary gap than individual and labor market characteristics. The effect of race on salary is shown to be weaker for librarians than for support staff

Using New Venture Competitions to Link the Library and Business Students

New venture competitions are designed to motivate university students to develop business plans and to present them to a panel of judges including business community members. Wilfrid Laurier University has integrated the new venture competition into its business school curriculum.This paper intends to share the experience of a new business librarian at Laurier Library in working with faculty to assist students to prepare for the new venture competition. A short survey is conducted to evaluate how students use the library resources and services for completing their projects. The results show that course guides and databases are the most used library resources. Marketline, Passport and Financial Performance Data are three databases found most useful by the students. Expectations of the liaison librarian include creating a tailored guide for the competition, delivering instruction sessions and providing research consultations on a continuing basis. It is critical to build close partnerships with faculty and to provide tailored services after fully assessing students’ needs

Using New Venture Competitions to Link the Library and Business Students

New venture competitions are designed to motivate university students to develop business plans and to present them to a panel of judges including business community members. Wilfrid Laurier University has integrated the new venture competition into its business school curriculum.This paper intends to share the experience of a new business librarian at Laurier Library in working with faculty to assist students to prepare for the new venture competition. A short survey is conducted to evaluate how students use the library resources and services for completing their projects. The results show that course guides and databases are the most used library resources. Marketline, Passport and Financial Performance Data are three databases found most useful by the students. Expectations of the liaison librarian include creating a tailored guide for the competition, delivering instruction sessions and providing research consultations on a continuing basis. It is critical to build close partnerships with faculty and to provide tailored services after fully assessing students’ needs