Second-order Shape Optimization for Geometric Inverse Problems in Vision

We develop a method for optimization in shape spaces, i.e., sets of surfaces modulo re-parametrization. Unlike previously proposed gradient flows, we achieve superlinear convergence rates through a subtle approximation of the shape Hessian, which is generally hard to compute and suffers from a series of degeneracies. Our analysis highlights the role of mean curvature motion in comparison with first-order schemes: instead of surface area, our approach penalizes deformation, either by its Dirichlet energy or total variation. Latter regularizer sparks the development of an alternating direction method of multipliers on triangular meshes. Therein, a conjugate-gradients solver enables us to bypass formation of the Gaussian normal equations appearing in the course of the overall optimization. We combine all of the aforementioned ideas in a versatile geometric variation-regularized Levenberg-Marquardt-type method applicable to a variety of shape functionals, depending on intrinsic properties of the surface such as normal field and curvature as well as its embedding into space. Promising experimental results are reported

Electronic double-excitations in quantum wells: solving the two-time Kadanoff-Baym equations

For a quantum many-body system, the direct population of states of double-excitation character is a clear indication that correlations importantly contribute to its nonequilibrium properties. We analyze such correlation-induced transitions by propagating the nonequilibrium Green's functions in real-time within the second Born approximation. As crucial benchmarks, we compute the absorption spectrum of few electrons confined in quantum wells of different width. Our results include the full two-time solution of the Kadanoff-Baym equations as well as of their time-diagonal limit and are compared to Hartree-Fock and exact diagonalization data

Electronic correlations in double ionization of atoms in pump-probe experiments

The ionization dynamics of a two-electron atom in an attosecond XUV-infrared pump-probe experiment is simulated by solving the time-dependent two-electron Schr\"odinger equation. A dramatic change of the double ionization (DI) yield with variation of the pump-probe delay is reported and the governing role of electron-electron correlations is shown. The results allow for a direct control of the DI yield and of the relative strength of double and single ionization

A Quality Improvement Project to Evaluate Auditor Satisfaction with Different Data Collection Methods for Auditing Compliance with Catheter Associated Urinary Tract Infection (CAUTI) Prevention Standards

Executive Summary A Quality Improvement Project to Evaluate Auditor Satisfaction with Different Data Collection Methods for Auditing Compliance with (CAUTI) Prevention Standards Problem Catheter-associated urinary tract infections (CAUTIs) are among the most common healthcare-associated infection (HAI) in the United States, representing about 40% of all HAIs (Palmer, Lee, Dutta-Linn, Wroe & Hartmann, 2013). Approximately 25% of indwelling urinary catheters are unnecessary and may potentially lead to CAUTIs if not maintained, cleaned, and cared for appropriately (Nazarko, 2012). Literature suggests that preventing CAUTIs is possible by implementing evidence based prevention standards. The PICO research question for CAUTI prevention and prevention standard data collection is: In a sampling of clinical auditors (P) does implementation of an electronic audit tool to collect data on compliance with CAUTI prevention care standards in addition to education on the electronic audit tool (I) differ from paper form auditing for CAUTI prevention care standards (C) and does it impact auditor satisfaction and/or data collected using the new tool (O). Goal The goal of this project was to assess if there were differences in paper versus electronic audit collection methods by evaluating pre- and post-implementation auditor satisfaction. In addition, an assessment of the two collection methods was completed to evaluate consistency related to number of audits collected and notable changes in compliance, thereby providing insight into if electronic data capture (EDC) is a reliable and efficient method. Objectives Project objectives included determining auditor satisfaction with paper versus electronic data collection methods and evaluation of implications of reliability with data collection methods by maintaining consistency with data. Plan Following Institutional Review Board approval from Regis University, the project was implemented and data were collected retro- and prospectively. There was an organizational transition to EDC, a questionnaire was distributed eliciting feedback from auditors on their satisfaction level, and compliance with the prevention standards was assessed for consistency pre- and post-implementation of the EDC tool. Questionnaire data were coded and entered into a spreadsheet and statistical software was used to determine if there were significant changes in auditor satisfaction. Finally, an assessment of differences in processes used to collect CAUTI prevention standard data was completed. Outcomes and Results Nine clinical auditors and one data analyst were exposed to both paper and EDC tools and completed the questionnaire. While there was not a statistically significant increase in satisfaction, there was a clinically significant increase in auditor satisfaction. There was a statistically significant difference noted between pre- and post- implementation compliance data, but this does not prove a causal relationship due to other confounding factors. There was also a statistically significant decrease in average time it took for auditors to collect audit data

Morphology of Stylops advarians (Strepsiptera) and the Effects of Parasitization on its Host, Andrena milwaukeensis (Hymenoptera)

Strepsiptera is an enigmatic order of endoparasitic insects known for the extreme sexual dimorphism of the adults, which results in a unique lifecycle. Adult males are free-living, whereas adult females of most of the order’s taxa are neotenic and permanently endoparasitic. Stylops advarians Pierce, a parasite of Andrena milwaukeensis Graenicher, was collected in central Saskatchewan, Canada and verified to species according to the DNA sequencing analysis of a mitochondrial cytochrome oxidase I. The morphology of the adult male, and the structure of the adult female and first-instar larva, were examined. The adult male was described for the first time from the puparia of a single host. Notable features were the metathoracic scutellum, which reaches close to the prescutum, the antennae, with the fourth antennomere being less than twice as long as the fifth, and the hook-like aedeagus. Like other Stylops species, the adult female of S. advarians lacked many adult characteristics, with only her cephalothorax having identifiable features. Impact of the female parasite on her host was examined. Female bees that were stylopized by one or more parasitic females did not have any eggs, nor reproductive organs, within their abdomens, as opposed to non-stylopized bees. Internally within the host gaster, the foregut and partial midgut of bees with one female parasite were shifted away from the parasite. If two or three parasites were present, then the gaster’s components of the digestive tract were shifted below the parasites. The crop was heavily reduced in volume when parasitism occurred, but the hindgut was not greatly affected. The female parasites were found to reside above an air sac within their host’s gaster. First-instar larvae have several sensory structures on their head, including eye spots, olfactory pits, and numerous pairs of setae. On the legs, the pro- and mesothoracic tarsi are modified as adhesive structures, whereas those of the metathoracic legs are likely only used for movement. Similarly, the tips of the caudal filaments likely have an adhesive function, and the coarse hairs (spinulae) covering the thorax and abdomen on both dorsal and ventral surfaces likely help these larvae phoretically attach onto a host. For the first time, first-instars were reported on the surface of a non-stylopized host of A. milwaukeensis, as well as inside the crop of a non-stylopized A. milwaukeensis, likely as phoronts. Field-collection data for foraging bees of A. milwaukeensis was also recorded to determine seasonal occurrence of stylopization and different parameters of the parasite’s life history, including prevalence, intensity, and abundance, within this bee population. From greater than 450 bees taken over three consecutive years (2016–2018), from early May to late June, the prevalence of stylopized bees was found to be around 22% (21–24%). Despite attempts, males were not collected consistently, so their data are not included in this prevalence. The mean intensity of parasite infection was 1.2 (1.167–1.244) and parasite abundance was 0.27 (0.258–¬0.276), strongly suggesting that the current relationship of S. advarians parasitizing A. milwaukeensis, at this study site, is in balance. Stylopized female bees were found to emerge earlier than non-stylopized bees, possibly due to manipulation by the parasite. Mating of the parasites evidently occurred during this emergence, which was around May 2 each year. First-instar larvae began to emerge around May 22, suggesting mating takes place at similar times each year, and that the developmental period of the first-instars is short

Non-equilibrium Green's function approach to inhomogeneous quantum many-body systems using the Generalized Kadanoff Baym Ansatz

In non-equilibrium Green's function calculations the use of the Generalized Kadanoff-Baym Ansatz (GKBA) allows for a simple approximate reconstruction of the two-time Green's function from its time-diagonal value. With this a drastic reduction of the computational needs is achieved in time-dependent calculations, making longer time propagation possible and more complex systems accessible. This paper gives credit to the GKBA that was introduced 25 years ago. After a detailed derivation of the GKBA, we recall its application to homogeneous systems and show how to extend it to strongly correlated, inhomogeneous systems. As a proof of concept, we present results for a 2-electron quantum well, where the correct treatment of the correlated electron dynamics is crucial for the correct description of the equilibrium and dynamic properties