Spectral shift function for a discretized continuum

A spectral shift function (SSF) is an important object in the scattering theory which is related both to the spectral density and to the scattering matrix. In the paper, it is shown how to employ the SSF formalism to solve scattering problems when the continuum is discretized, e.g. when solving a scattering problem in a finite volume or in the representation of some finite square-integrable basis. A new algorithm is proposed for reconstructing integrated densities of states and the SSF using a union of discretized spectra corresponding to a set of Gaussian bases with the shifted scale parameters. The examples given show that knowledge of the discretized spectra of the total and asymptotic Hamiltonians is sufficient to find the scattering partial phase shifts at any required energy, as well as the resonances parameters.

Research Data Services: Partnerships

The Association of Research Libraries (ARL)/Canadian Association of Research Libraries (CARL) Joint Task Force on Research Data Services (RDS) formed in 2020 with a two-fold purpose: (1) to demonstrate and commit to the roles research libraries have in stewarding research data and as part of institution-wide research support services and (2) to guide the development of resources for the ARL and CARL memberships in advancing their organizations as collaborative partners with respect to research data services in the context of FAIR (findable, accessible, interoperable, and reusable) data principles and the US National Academies’ Open Science by Design framework. Research libraries will be successful in meeting these objectives if they act collectively and are deeply engaged with disciplinary communities. The task force formed three working groups of data practitioners, representing a wealth of expertise, to research the institutional landscape and policy environment in both the US and Canada. This report of the ARL/CARL RDS task force’s working group on partnerships highlights library RDS programs’ work with partners and stakeholders. The report provides a set of tools for libraries to use when assessing their RDS partnerships, including assessing partnerships using a partnership life cycle, defining the continuum of possible partnerships, and creating a catalog. Not all partnerships will last the entirety of a librarian’s career, and having clear parameters for when to continue or sunset a partnership can reduce ambiguity and free up resources. Recognizing the continuum of possible partnerships can provide the framework by which librarians can understand the nature of each group. From cyclical to seasonal to sporadic, understanding the needs of a type of partnership can help libraries frame their understanding and meet a group where they are. Finally, creating a catalog of partnerships can help libraries see the landscape of the organization, as well as areas for growth. This approach also aligns with OCLC’s 2020 report on Social Interoperability in Research Support: Cross-Campus Partnerships and the University Research Enterprise, which highlights the necessity of building and stewarding partnerships. Developing and providing services in a decentralized organization relies on the ability to build trusted relationships. These tools will help libraries achieve sustainable growth that is in concert with their partners, generating robust, clearly aligned initiatives that benefit all parties, their campuses, and their communities.

Re-Thinking the Roles of Pathogens and Mutualists: Exploring the Continuum of Symbiosis in the Context of Microbial Ecology and Evolution

Systems of classification are important for guiding research activities and providing a common platform for discussion and investigation. One such system is assigning microbial taxa to the roles of mutualists and pathogens. Yet, there are often challenges and even inconsistencies in reports of research findings when microbial taxa display behaviors outside of these two static conditions (e.g. commensal). Over the last two decades, there has been some effort to highlight a continuum of symbiosis, wherein certain microbial taxa may exhibit mutualistic or pathogenic traits depending on environmental contexts, life stages, and plant host associations. However, gaps remain in understanding how to apply the continuum approach to host-microbe pairs across a range of environmental and ecological factors. This commentary presents an alternative framework for evaluating the continuum of symbiosis using dominant archetypes that define symbiotic ranges. We focus particularly on fungi and bacteria, though we recognize that archaea and other microeukaryotes play important roles in host-microbe interactions that may be described by this approach. This framework is centered in eco-evolutionary theory and aims to enhance communication among researchers, as well as prioritize holistic consideration of the factors shaping microbial life strategies. We discuss the influence of plant-mediated factors, habitat constraints, co-evolutionary forces, and the genetic contributions which shape different microbial lifestyles. Looking to the future, using a continuum of symbiosis paradigm will enable greater flexibility in defining the roles of target microbes and facilitate a more holistic view of the complex and dynamic relationship between microbes and plants.

Unifying polar and nematic active matter: Emergence and co-existence of half-integer and full-integer topological defects

The presence and significance of active topological defects is increasingly realised in diverse biological and biomimetic systems. We introduce a continuum model of polar active matter, based on conservation laws and symmetry arguments, that recapitulates both polar and apolar (nematic) features of topological defects in active turbulence. Using numerical simulations of the continuum model, we demonstrate the emergence of both half- and full-integer topological defects in polar active matter. Interestingly, we find that crossover from active turbulence with half- to full-integer defects can emerge with the coexistence region characterized by both defect types. These results put forward a minimal, generic framework for studying topological defect patterns in active matter which is capable of explaining the emergence of half-integer defects in polar systems such as bacteria and cell monolayers, as well as predicting the emergence of coexisting defect states in active matter.

Integration of Medication Safety Training and Development of a Culture of Safety in Pharmacy Education

Medication safety events with the potential for patient harm do occur in health care settings. Pharmacists are regularly tasked with utilizing their medication knowledge to optimize the medication use process and reduce the likelihood of error. To prepare for these responsibilities in professional practice, it is important to introduce patient safety principles during educational experiences. The Accreditation Council for Pharmacy Education (ACPE) and the American Society of Health-System Pharmacists (ASHP) have set forth accreditation standards focused on the management of medication use processes to ensure these competencies during pharmacy didactic learning and postgraduate training. The experience described here provides perspective on educational and experiential opportunities across the continuum of pharmacy education, with a focus on a relationship between a college of pharmacy and healthcare system. Various activities, including discussions, medication event reviews, audits, and continuous quality improvement efforts, have provided the experiences to achieve standards for these pharmacy learners. These activities support a culture of safety from early training.

Symmetries of Thirring Models on 3D Lattices

We review some recent developments about strongly interacting relativistic Fermi theories in three spacetime dimensions. These models realize the asymptotic safety scenario and are used to describe the low-energy properties of Dirac materials in condensed matter physics. We begin with a general discussion of the symmetries of multi-flavor Fermi systems in arbitrary dimensions. Then we review known results about the critical flavor number $N_\mathrm{crit}$ of Thirring models in three dimensions. Only models with flavor number below $N_\mathrm{crit}$ show a phase transition from a symmetry-broken strong-coupling phase to a symmetric weak-coupling phase. Recent simulations with chiral fermions show that $N_\mathrm{crit}$ is smaller than previously extracted with various non-perturbative methods. Our simulations with chiral SLAC fermions reveal that for four-component flavors $N_\mathrm{crit}=0.80(4)$. This means that all reducible Thirring models with $\Nr=1,2,3,\dots$ show no phase transition with order parameter. Instead we discover footprints of phase transitions without order parameter. These new transitions are probably smooth and could be used to relate the lattice Thirring models to Thirring models in the continuum. For a single irreducible flavor, we provide previously unpublished values for the critical couplings and critical exponents.