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Groundwater Interaction and Surface Water Impacts on the Ground- Coupled Geothermal Heat Exchanger at Carleton College
No full textGround-coupled closed-loop geothermal heat exchangers are highly efficient alternatives to fossil fuels to reduce emissions for building heating and cooling systems. Implementing geothermal heat exchangers increases efficiency when deployed at a district scale, but risks altering the geochemistry of the groundwater due to elevated subsurface temperature. In 2018, Carleton College (Northfield, MN) installed a district-scale closed-loop geothermal heat exchanger with 95 horizontal 155 m long bores beneath Ordovician sedimentary rocks. The temperature of groundwater was measured in 5 observation wells installed between the edge of the borefield and Spring Creek—a small deep-aquifer-sourced spring-fed tributary of the Cannon River that runs around the perimeter of the borefield. The temperature of the creek was recorded to distinguish the thermal inputs from springs, and potential infiltration from shallow geothermally heated groundwater flowing from the borefield. Clear heat signatures from the heat exchanger in Spring Creek indicate substantive groundwater flow, consistent with prior studies at Carleton. However, spring inputs mitigate the heating and cooling effects on creek temperature by the heat exchanger. Consequently, the resulting creek temperature profile does not appear to have an environmentally concerning temperature change. Groundwater temperature does increase downstream of the borefield, but groundwater flow is rapid enough to avoid thermal buildup across seasons. Further monitoring is required to evaluate if the subsurface groundwater temperature increases on an annual basis
Understanding the ATP-Mediated CFTR Gating Mechanism Using Biophysical Chemical Techniques
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Ghosts
No full textI think we all have ghosts, whether or not we believe in life after death. A ghost can be a hollow where someone once was, or a memory twisted by time. They are made up of both desire and fear; they are dreams woven into the fabric of our lives. Through clay, I put language to the ghosts in my life using horses as a motif. These strange, magical creatures were a fixture in the folklore of my childhood. Hanging from the skeletons of mattresses, they cluster to form the shadow silhouettes of people when viewed from a certain angle
A Horizontal Leg Up: Skewed Incidence and Advantage of Horizontal Gene Transfer between Eukaryotic Parasite and Host
No full textHost and parasite present as potential donors of HGT to the other, and in the far majority of cases, I observe parasites benefiting from this new avenue of HGT. Primarily we will consider what host-derived novel genes and functions make parasites so likely to conserve HGT from their hosts. In addition, although the specific mechanisms involved in eukaryotic HGT are largely unknown, some trends in transmission are clear and may inform the observed skew of directionality towards parasites. In concert with transmission factors, eukaryotic parasites gain a relatively high incidence of HGT from their hosts due to host-derived genes\u27 unique parasitic fitness advantages
Investigating the Role of PPAR�� in Peroxisome-Mediated Sebum Production and the Pathophysiology of Acne Vulgaris
No full textThe Long Road: Comparison of Approximation Heuristics for Traveling Salesperson Problem
No full textThe Traveling Salesperson Problem is a fundamental problem in graph theory. The problem statement says given a set of cities, what is the shortest possible route visiting each city exactly once before returning to the initial city . As it is a NP-hard problem, there are no known algorithms that solve it in polynomial time. However, different approximation algorithms can generate results to some degree of accuracy and satisfactory computational efficiency. In this study, we implemented and analyzed three algorithms for approximating solutions to the Traveling Salesperson Problem: the Nearest Neighbor heuristic, the Smallest Insertion heuristic, and the Christofides algorithm. The first two are fast greedy approaches, that are conceptually simple and easy to implement but generate solutions which are far from optimal. The third, Christofides algorithm, is close to state of the art, yields a solution within 1.5 times the optimal distance but has a higher computational cost. We evaluated these algorithms on a number of datasets, including country maps, electrical grids, protein interaction networks, and synthetic data. Our analysis compared the solution accuracy and runtime of each heuristic across graphs ranging from 10 to 16,862 nodes. The results offer insight in how each approximation algorithm fares in terms of computational cost and accuracy, helping make more informed decisions in problem solving
The Experience Machine
No full textThe Experience Machine is a two player game where one player can control the parameters of the world, and the other moves around it and takes pictures. Each world is randomly generate