Replicating analyses of item response curves using data from the Force and Motion Conceptual Evaluation

Ishimoto, Davenport, and Wittmann have previously reported analyses of data from student responses to the Force and Motion Conceptual Evaluation (FMCE), in which they used item response curves (IRCs) to make claims about American and Japanese students’ relative likelihood to choose certain incorrect responses to some questions. We have used an independent dataset of over 6,500 American students’ responses to the FMCE to generate IRCs to test their claims. Converting the IRCs to vectors, we used dot product analysis to compare each response item quantitatively. For most questions, our analyses are consistent with Ishimoto, Davenport, and Wittmann, with some results suggesting more minor differences between American and Japanese students than previously reported. We also highlight the pedagogical advantages of using IRCs to determine the differences in response patterns for different populations to better understand student thinking prior to instruction

Advanced Quantum Poisson Solver in the NISQ era

The Poisson equation has many applications across the broad areas of science and engineering. Most quantum algorithms for the Poisson solver presented so far, either suffer from lack of accuracy and/or are limited to very small sizes of the problem, and thus have no practical usage. Here we present an advanced quantum algorithm for solving the Poisson equation with high accuracy and dynamically tunable problem size. After converting the Poisson equation to the linear systems through the finite difference method, we adopt the Harrow-Hassidim-Lloyd (HHL) algorithm as the basic framework. Particularly, in this work we present an advanced circuit that ensures the accuracy of the solution by implementing non-truncated eigenvalues through eigenvalue amplification as well as by increasing the accuracy of the controlled rotation angular coefficients, which are the critical factors in the HHL algorithm. We show that our algorithm not only increases the accuracy of the solutions, but also composes more practical and scalable circuits by dynamically controlling problem size in the NISQ devices. We present both simulated and experimental solutions, and conclude that overall results on the quantum hardware are dominated by the error in the CNOT gates.Comment: Quantum Week QCE 2022, poster pape

Advancing Algorithm to Scale and Accurately Solve Quantum Poisson Equation on Near-term Quantum Hardware

The Poisson equation has many applications across the broad areas of science and engineering. Most quantum algorithms for the Poisson solver presented so far either suffer from lack of accuracy and/or are limited to very small sizes of the problem, and thus have no practical usage. Here we present an advanced quantum algorithm for solving the Poisson equation with high accuracy and dynamically tunable problem size. After converting the Poisson equation to a linear system through the finite difference method, we adopt the HHL algorithm as the basic framework. Particularly, in this work we present an advanced circuit that ensures the accuracy of the solution by implementing non-truncated eigenvalues through eigenvalue amplification, as well as by increasing the accuracy of the controlled rotation angular coefficients, which are the critical factors in the HHL algorithm. Consequently, we are able to drastically reduce the relative error in the solution while achieving higher success probability as the amplification level is increased. We show that our algorithm not only increases the accuracy of the solutions but also composes more practical and scalable circuits by dynamically controlling problem size in NISQ devices. We present both simulated and experimental results and discuss the sources of errors. Finally, we conclude that though overall results on the existing NISQ hardware are dominated by the error in the CNOT gates, this work opens a path to realizing a multidimensional Poisson solver on near-term quantum hardware.Comment: 13 pages, 11 figures, 1 tabl

Relationship Between Bone Bruise Volume and Patient Outcomes After ACL Reconstruction

BACKGROUND: Subchondral bone injuries, or bone bruises, are commonly observed on magnetic resonance imaging (MRI) after anterior cruciate ligament (ACL) injury. The current relationship between bone bruise volume and postsurgical outcomes remains poorly understood. PURPOSE: To examine the influence of bone bruise volume on self-reported and objective functional outcomes at the time of return to play and 2 years following ACL reconstruction. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Clinical, surgical, and demographic data were obtained for a sample of convenience utilizing a single-surgeon ACL database (n = 1396). For 60 participants, femoral and tibial bone bruise volumes were estimated from preoperative MRI. Data obtained at the time of return to play included International Knee Documentation Committee (IKDC-2000) score, ACL-Return to Sport after Injury (ACL-RSI) score, and performance on an objective functional performance battery. Two-year follow-up data included graft reinjury rate, level of return to sport/activity, and self-reported knee function using the Single Assessment Numeric Evaluation (SANE). The forward stepwise linear regression was used to determine the relationship between bone bruise volume and patient function. RESULTS: The distribution of bone bruise injuries was as follows: lateral femoral condyle (76.7%), lateral tibial plateau (88.3%), medial femoral condyle (21.7%), and medial tibial plateau (26.7%). Mean total bone bruise volume of all compartments was 7065.7 ± 6226.6 mm CONCLUSION: The lateral tibial plateau was the most frequent site to sustain bone bruise injury. Preoperative bone bruise volume was not associated with delayed time to return to sport or self-reported outcomes at time of return to play or at 2 years postoperatively. REGISTRATION: NCT03704376 (ClinicalTrials.gov identifier)

Self-intersecting Regge trajectories in multi-channel scattering

We present a simple direct method for calculating Regge trajectories for a multichannel scattering problem. The approach is applied to the case of two coupled Thomas-Fermi type potentials, used as a crude model for electron-atom scattering below the second excitation threshold. It is shown that non-adiabatic interaction may cause formation of loops in Regge trajectories. The accuracy of the method is tested by evaluating resonance contributions to elastic and inelastic integral cross sections.Comment: 5 pages, 4 figure

Is stemflow a vector for the transport of small metazoans from tree surfaces down to soil?

Ptatscheck C, Milne PC, Traunspurger W. Is stemflow a vector for the transport of small metazoans from tree surfaces down to soil? BMC Ecology. 2018;18(1): 43.Background Stemflow is an essential hydrologic process shaping the soil of forests by providing a concentrated input of rainwater and solutions. However, the transport of metazoans by stemflow has yet to be investigated. This 8-week study documented the organisms (< 2 mm) present in the stemflow of different tree species. Because the texture of the tree bark is a crucial determination of stemflow, trees with smooth bark (Carpinus betulus and Fagus sylvatica) and rough bark (Quercus robur) were examined. Results Up to 1170 individuals per liter of stemflow were collected. For rotifers and nematodes, a highly positive correlation between abundance and stemflow yield was determined. Both taxa were predominant (rotifers: up to 70%, nematodes: up to 13.5%) in the stemflow of smooth-barked trees whereas in that of the oak trees collembolans were the most abundant organisms (77.3%). The mean number of organisms collected per liter of stemflow from the two species of smooth-barked trees was very similar. A higher number of nematode species was found in the stemflow of these trees than in the stemflow of rough-barked oak and all were typical colonizers of soil- and bark-associated habitats. Conclusion This pilot study showed for the first time that stemflow is a transport vector for numerous small metazoans. By connecting tree habitats (e.g., bark, moss, lichens or water-filled tree holes) with soil, stemflow may influence the composition of soil fauna by mediating intensive organismal dispersal