Clawpack: Building an Open Source Ecosystem for Solving Hyperbolic PDEs

Clawpack is a software package designed to solve nonlinear hyperbolic partial differential equations using high-resolution finite volume methods based on Riemann solvers and limiters. The package includes a number of variants aimed at different applications and user communities. Clawpack has been actively developed as an open source project for over 20 years. The latest major release, Clawpack 5, introduces a number of new features and changes to the code base and a new development model based on GitHub and Git submodules. This article provides a summary of the most significant changes, the rationale behind some of these changes, and a description of our current development model

Student Learning Centers - Key to Transition from Traditional to Open Classroom

It is the purpose of this project to provide a transition from the traditional classroom into an open classroom through the use of modular group-oriented and individualized learning centers. The transitional approach is designed to assist the student to assume responsibilities needed to function successfully and comfortably in a new school environment, the open classroom

Simulating the 1976 Teton Dam Failure using Geoclaw and HEC-RAS and comparing with Historical Observations

Dam failures occur worldwide, often from factors including aging structures, extreme hydrologic loading, and design oversights related to the changing climate. Understanding and mitigating risk to downstream inhabited areas require developing and improving low-cost high-fidelity tools, such as numerical models, which allow emergency managers to predict the consequences of dam failures better. Two-dimensional (2D) depth-averaged hydraulic models can provide valuable insights into the importance of breach parameters or downstream flow characteristics, but historical studies considering historic failures using real topographies are less common in literature. This study compares Geoclaw, a 2D hydraulic model with adaptive mesh refinement capabilities, to an industry-standard software HEC-RAS (Hydrologic Engineering Center - River Analysis System) using the 1976 Teton Dam failure as a case study. The suitability of Geoclaw for dam failure modeling is determined based on its capability to resolve inundation extent and flood wave arrival times. This study performs sensitivity analyses of the HEC-RAS model to compare an instantaneous dam breach assumption with a time-dependent breach formation for quantifying the model uncertainty. We find the 2D Geoclaw dam-break model results compare reasonably with historical gauge and field observational data and HEC-RAS results. The model demonstrates stability and relatively low computational costs. Our findings highlight opportunities for future work, with the Geoclaw software performance supporting continued studies to evaluate performance. Outcomes of this study will assist dam owners, floodplain managers, and emergency managers by providing an additional tool for estimating the impacts of dam failures to protect lives and infrastructure downstream

Numerical simulation of diffusion MRI signals using an adaptive time-stepping method

International audienceThe effect on the MRI signal of water diffusion in biological tissues in the presence of applied magnetic field gradient pulses can be modelled by a multiple compartment Bloch-Torrey partial differential equation. We present a method for the numerical solution of this equation by coupling a standard Cartesian spatial discretization with an adaptive time discretization. The time discretization is done using the explicit Runge-Kutta-Chebyshev method, which is more efficient than the forward Euler time discretization for diffusive-type problems. We use this approach to simulate the diffusion MRI signal from the extra-cylindrical compartment in a tissue model of the brain gray matter consisting of cylindrical and spherical cells and illustrate the effect of cell membrane permeability

GPU Accelerated Adaptive Wave Propagation Algorithm

The GPU performance of the adaptive wave propagation algorithm is critical to its effectiveness in simulating wave propagation in complex media. This algorithm employs adaptive mesh refinement to improve resolution in areas where the wavefield is changing rapidly. The algorithm\u27s performance is significantly improved by the use of graphics processing units (GPUs), which offer faster computation times than traditional central processing units (CPUs). According to the studies in this poster, GPU acceleration of the adaptive wave propagation algorithm provides significant improvements in simulation speed and scalability, as seen in the simulated examples: scalar advection, shallow water equations, euler, and acoustics. When compared to traditional CPU-based algorithms, the algorithm can handle larger models and produce higher resolution results at a faster rate. The algorithm\u27s efficiency and effectiveness are determined by the specific hardware and software configuration of the GPU used; for this study, we used INL Borah

Age-Related Changes in Processing Speed: Unique Contributions of Cerebellar and Prefrontal Cortex

Age-related declines in processing speed are hypothesized to underlie the widespread changes in cognition experienced by older adults. We used a structural covariance approach to identify putative neural networks that underlie age-related structural changes associated with processing speed for 42 adults ranging in age from 19 to 79 years. To characterize a potential mechanism by which age-related gray matter changes lead to slower processing speed, we examined the extent to which cerebral small vessel disease influenced the association between age-related gray matter changes and processing speed. A frontal pattern of gray matter and white matter variation that was related to cerebral small vessel disease, as well as a cerebellar pattern of gray matter and white matter variation were uniquely related to age-related declines in processing speed. These results demonstrate that at least two distinct factors affect age-related changes in processing speed, which might be slowed by mitigating cerebral small vessel disease and factors affecting declines in cerebellar morphology

Money Minute: Using short informational videos during COVID-19

The COVID-19 pandemic has created a money crunch for some families. To help families struggling financially while capitalizing on at-home time, The University of Tennessee (UT) Extension consumer economics leadership team developed a series of money management videos called Money Minute. The primary purpose of the videos was to provide research-based financial education during this time of financial hardships. Filmed using Zoom, each video offers a piece of research-based information, additional resources, and a call to action. The video series proved to be effective in reaching clientele with financial information in the midst of a pandemic

Can asthma control be improved by understanding the patient's perspective?

Clinical trials show that asthma can be controlled in the majority of patients, but poorly controlled asthma still imposes a considerable burden. The level of asthma control achieved reflects the behaviour of both healthcare professionals and patients. A key challenge for healthcare professionals is to help patients to engage in self-management behaviours with optimal adherence to appropriate treatment. These issues are particularly relevant in primary care, where most asthma is managed. An international panel of experts invited by the International Primary Care Respiratory Group considered the evidence and discussed the implications for primary care practice