A Theoretical Foundation for Count Data Models

The paper develops a theoretical foundation for using count data models in travel cost analysis. Two micro models are developed: a restricted choice model and a repeated discrete choice model. We show that both models lead to identical welfare measures.

Pedagogical Tool for Usability Science Final Project Report

A Sophomore Research Seminar (SRS) at Union College teaches about usability science, the study of designing interfaces that allow the user to accomplish a given task with less time and frustration. In this context, an interface can be anything that allows interaction with a physical or virtual device such as a web browser or the knobs on a stove. In this SRS, students design interface mockups, called prototypes, out of inexpensive material such as cardboard. Students use these prototypes to test their interfaces on real people, who are asked to perform a task that would be performed on a real appliance. The researcher physically interacts with the prototype to simulate the function of the appliance. The purpose is to gather data, like the amount of time or attempts it takes the user to accomplish their task. The problem with this method of usability testing is that the researcher’s interaction can affect the validity of the data. The goal of my project is to develop a system that allows the students to create prototypes that do not require interaction during testing. This involves building devices called widgets: physical devices such as LEDs or switches that represent components of household appliances. I’m also developing a programming language that defines the interaction between widgets. Using both parts students will be able to design working mockups of household appliances

A Theoretical Foundation for Count Data Models

The paper develops a theoretical foundation for using count data models in travel cost analysis. Two micro models are developed: a restricted choice model and a repeated discrete choice model. We show that both models lead to identical welfare measures

Validation of Oil Trajectory and Fate Modeling of the Deepwater Horizon Oil Spill

Trajectory and fate modeling of the oil released during the Deepwater Horizon blowout was performed for April to September of 2010 using a variety of input data sets, including combinations of seven hydrodynamic and four wind models, to determine the inputs leading to the best agreement with observations and to evaluate their reliability for quantifying exposure of marine resources to floating and subsurface oil. Remote sensing (satellite imagery) data were used to estimate the amount and distribution of floating oil over time for comparison with the model’s predictions. The model-predicted locations and amounts of shoreline oiling were compared to documentation of stranded oil by shoreline assessment teams. Surface floating oil trajectory and distribution was largely wind driven. However, trajectories varied with the hydrodynamic model used as input, and was closest to observations when using specific implementations of the HYbrid Coordinate Ocean Model modeled currents that accounted for both offshore and nearshore currents. Shoreline oiling distributions reflected the paths of the surface oil trajectories and were more accurate when westward flows near the Mississippi Delta were simulated. The modeled movements and amounts of oil floating over time were in good agreement with estimates from interpretation of remote sensing data, indicating initial oil droplet distributions and oil transport and fate processes produced oil distribution results reliable for evaluating environmental exposures in the water column and from floating oil at water surface. The model-estimated daily average water surface area affected by floating oil \u3e1.0 g/m2 was 6,720 km2, within the range of uncertainty for the 11,200 km2 estimate based on remote sensing. Modeled shoreline oiling extended over 2,600 km from the Apalachicola Bay area of Florida to Terrebonne Bay area of Louisiana, comparing well to the estimated 2,100 km oiled based on incomplete shoreline surveys

Bilateral Pedicle and Crossed Translaminar Screws in C2

Multiple techniques exist for the fixation of C2, including axial pedicle screws and bilateral translaminar screws. We describe a novel method of incorporating both the translaminar and pedicle screws within C2 to improve fixation to the subaxial spine in patients requiring posterior cervical instrumentation for deformity correction or instability. We report three cases of patients with cervical spinal instability, who underwent cervical spine instrumentation for stabilization and/or deformity correction. Bilateral C2 pedicle screws were inserted, followed by bilateral crossed laminar screws. The instrumentation method successfully achieved fixation in all three patients. There were no immediate postoperative complications, and hardware positioning was satisfactory. Instrumenting C2 with translaminar and pedicle screws is technically feasible, and it may improve fixation to the subaxial spine in patients with poor bone quality or severe subaxial deformity, which require a stronger instrumentation construct

The Grizzly, March 28, 2019

Alumni Award Winners Announced • Diversity Monologues: A Night of Sharing • Ursinus Honors Dr. Crigler\u27s Legacy • Changing Comic Books One Superhero at a Time • Tess Beck \u2720 Embracing Aussie • Ursinus Students Building Houses in South Carolina • Opinions: College Admissions Scandal is Shocking, but not Surprising; Backlash Against Rep. Omar Underlines Weakness in Democratic Leadership • The Off to an Historic Start Award: Dom Fiorentino • Women\u27s Lacrosse Travels to Nashville and Earns First Win of the Season • UC Baseball Picking up Steam as Season Gets Into Full Swinghttps://digitalcommons.ursinus.edu/grizzlynews/1616/thumbnail.jp