On the spectra of certain diatomic hydride and deuteride molecules

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Fractal spectral triples on Kellendonk's C∗C^*-algebra of a substitution tiling

We introduce a new class of noncommutative spectral triples on Kellendonk's $C^*$-algebra associated with a nonperiodic substitution tiling. These spectral triples are constructed from fractal trees on tilings, which define a geodesic distance between any two tiles in the tiling. Since fractals typically have infinite Euclidean length, the geodesic distance is defined using Perron-Frobenius theory, and is self-similar with scaling factor given by the Perron-Frobenius eigenvalue. We show that each spectral triple is $\theta$-summable, and respects the hierarchy of the substitution system. To elucidate our results, we construct a fractal tree on the Penrose tiling, and explicitly show how it gives rise to a collection of spectral triples.Comment: Updated to agree with published versio

Charged stripes from alternating static magnetic field

We motivate and perform a calculation of the energy of a cold fluid of charged fermions in the presence of a striped magnetic background. We find that a non-trivial value for the doping density on the walls is preferredComment: RevTeX, 3 pages, 3 encapsulated PostScript figure

Orthogonal Polynomial Representation of Imaginary-Time Green's Functions

We study the expansion of single-particle and two-particle imaginary-time Matsubara Green's functions of quantum impurity models in the basis of Legendre orthogonal polynomials. We discuss various applications within the dynamical mean-field theory (DMFT) framework. The method provides a more compact representation of the Green's functions than standard Matsubara frequencies and therefore significantly reduces the memory-storage size of these quantities. Moreover, it can be used as an efficient noise filter for various physical quantities within the continuous-time quantum Monte Carlo impurity solvers recently developed for DMFT and its extensions. In particular, we show how to use it for the computation of energies in the context of realistic DMFT calculations in combination with the local density approximation to the density functional theory (LDA+DMFT) and for the calculation of lattice susceptibilities from the local irreducible vertex function.Comment: 14 pages, 11 figure

Hidden in plain sight:Using administrative data to conduct a longitudinal cohort study of children exposed to opioids in pregnancy

Objectives: Children of women who use substances are difficult to research at a population-level using traditional research methods due to the complexity of their lives. Resultingly, we have little robust evidence on their outcomes. This study developed an administrative data cohort of children exposed to opioids and explored health outcomes.Methods: Using data from birth records, antenatal records, prescription data, hospital/psychiatric hospital admissions, and drug and alcohol service data, we identified 6,408 children (born 2009-2019) in Scotland who were exposed to opioids through illicit use and/or medication assisted treatment (i.e. methadone/buprenorphine). A control group (n. 19,089) of children not exposed to opioids were matched on age of mother and Scottish Index of Multiple Deprivation. Data were described and linear and logistic regression models were used to examine the relationship between risk factors (such as drug and alcohol use in pregnancy, gestation at booking and at birth), and key early outcomes.Results: Although the majority of women had their substance use recorded in antenatal records, 28.9\% did not, demonstrating the importance of using multiple administrative datasets to form the cohort. Children in the cohort were more likely to experience a range of adverse outcomes including being born early (17\% born prematurely, compared with 6.5\% in control group), having a below normal Apgar score (the scoring system used to assess newborns shortly after birth) (2.9\% in cohort vs. 1.5\% in controls), having significantly lower birthweight, length and head circumference, and more likely to be removed from their mother prior hospital discharge. Differences between the cohorts remained after controlling for other risk factors including alcohol use, and gestation.Conclusion: This feasibility study brought together a cohort of children usually excluded from traditional forms of research. The research demonstrated early differences in outcomes between exposed children and others from similar socio-economic groups. The next stage of this research is exploring health and development outcomes in the preschool period

Inventory methods for sea asparagus in the Salish Sea: working with indigenous communities to integrate UAV technology and aquatic plant management

On the west coast of British Columbia, licences for the harvesting of sea asparagus are issued annually, requiring information on the baseline distribution and available biomass of the resource. While previous research has documented the biomass of sea asparagus in saltwater marshes of Boundary Bay and Cowichan Bay, this inventory is limited in geographic scope. Traditional ground transect survey methods are expensive and not feasible for expansion of inventory work across the Strait of Georgia. The use of small Unmanned Aerial Vehicles (UAVs) has gained recognition as a highly effective and accessible approach for mapping coastal vegetation. In this study, we developed and piloted a cost-effective methodology using UAV technology for the inventory of sea asparagus within a high priority area on the east coast of Vancouver Island. We combined field sampling methods with UAV surveys to provide ground-verified image coverage of saltwater marsh habitat. Photo-orthomosaics were used to produce a digital elevation model, from which area-based calculations for sea asparagus were developed. Area estimates were then converted to biomass based on ground-verification data. A key component of our approach was the involvement and participation of K’ómoks First Nation Guardian Watchmen. As stewards of their lands and waters, First Nation communities have a central interest in the management of commercial resources within their traditional territory. Indigenous-led UAV research provides the potential for new technology to benefit both ecosystems and communities