Selection of a Directional Preference in Drosophila melanogaster

Diverse organisms, including birds, sea turtles, lobsters, and sharks have been shown to use Earth-strength magnetic fields to navigate. We have examined whether the fruit fly Drosophila melanogaster has a directional preference and if this preference has genetic underpinnings. In order to answer these questions we designed a Y-maze in which each fly makes 10 sequential choices to go North or South. To breed a population of North-seeking flies, we recorded the distribution of flies exiting the maze and selected the Northern-most 20% to give rise to the next generation. We used a similar protocol to breed a population of South-seeking flies. Our data showed that wild-type Drosophila do not have a distinct innate preference for either North or South. Moreover, after 12 generations we did not produce a population of flies with a distinct directional preference. As a positive control we ran a similar experiment to look at phototaxis. Our data showed that flies exhibit positive phototaxis and after 12 generations of selective breeding we have produced a strain with a decreased phototaxic response. These experiments will be continued for 15 generations. Our findings will contribute to a better understanding of the magnetic orientation behavior of Drosophila

Building a Typed Scripting Language

Since the 1990s, scripting languages (e.g. Python, Ruby, JavaScript, and many others) have gained widespread popularity. Features such as ad-hoc data manipulation, dynamic structural typing, and terse syntax permit rapid engineering and improve developer productivity. Unfortunately, programs written in scripting languages execute slower and are less scalable than those written in traditional languages (such as C or Java) due to the challenge of statically analyzing scripting languages' semantics. Although various research projects have made progress on this front, corner cases in the semantics of existing scripting languages continue to defy static analysis and software engineers must generally still choose between program performance and programmer performance when selecting a language. We address that dichotomy in this dissertation by designing a scripting language with the intent of statically analyzing it. We select a set of core primitives in which common language features such as object-orientation and case analysis can be encoded and give a sound and decidable type inference system for it. Our type theory is based on subtype constraint systems but is also closely related to abstract interpretation; we use this connection to guide development of the type system and to employ a novel type soundness proof strategy based on simulation. At the heart of our approach is a type indexed record we call the onion which supports asymmetric concatenation and dispatch; we use onions to formally encode a variety of features, including records, operator overloading, objects, and mixins. An optimistic call-site polymorphism model defined herein captures the ad-hoc, case-analysis-based reasoning often used in scripting languages. Although the language in this dissertation uses a particular set of core primitives, the strategy we use to design it is general: we demonstrate a simple, formulaic process for adding features such as integers and state

Directional Preference in Drosophila melanogaster

Diverse organisms have been shown to use the Earth’s magnetic field for orientation and navigation, but the mechanisms underlying magnetoreception are still poorly understood. Recent research on magnetoreception has focused on the fruit fly Drosophila melanogaster primarily because of its role as a model organism for understanding the genetic mechanisms underlying behavioral traits. While current research suggests that Drosophila might be able to detect and orient to magnetic fields, different studies offer contradictory results. In this study, we used a Y-maze and selective breeding to attempt to create a population of fruit flies that display a robust magnetic orientation behavior. We used a Y-maze where each fly made 10 choices of whether to go north or south. Of flies that exited the maze, we selected the top 20% of flies from each run to produce the next generation. This protocol was repeated for 12 generations. Our data shows that wild-type Drosophila have no innate north or south preference, nor an innate east or west preference. Additionally, after 12 generations of selection, we have so far been unable to create populations of fruit flies with a magnetic orientation behavior. Further research includes continued selection on our current populations of flies as well as experimental design modifications that could possibly detect a more subtle magnetic orientation behavior

Camper Conversion

The COVID-19 pandemic of 2020-2021 has seen hundreds of thousands sequestered in quarantine for long periods of time. When quarantined in an urban setting, many cannot leave their respective apartment buildings which only adds to the strain of isolation. In the context of isolation, the design team of Hafler, Nicholas, Owen, Willis, and Zehentbauer personally sought to incorporate their individual enthusiasm for nature with the benefits of living off-grid. After initial research and deliberation, the team discovered the “Skoolie” community and the plans for a mobile tiny home began production. The team outlined the design project as the full design, purchase, and construction of a 54-passenger bus transformed into a mobile tiny home. The team highlights the terms “sustainable” and “off-grid” in the problem statement, this was done intentionally to ensure that all decisions made in the project were centralized back to these two main themes. By completing this project, the team will make a point to include all living amenities of an average student’s apartment such as hot water shower, fridge storage, living and recreation area, sleeping area for 4-5 adults

Better Together: Unifying Datalog and Equality Saturation

We present egglog, a fixpoint reasoning system that unifies Datalog and equality saturation (EqSat). Like Datalog, it supports efficient incremental execution, cooperating analyses, and lattice-based reasoning. Like EqSat, it supports term rewriting, efficient congruence closure, and extraction of optimized terms. We identify two recent applications--a unification-based pointer analysis in Datalog and an EqSat-based floating-point term rewriter--that have been hampered by features missing from Datalog but found in EqSat or vice-versa. We evaluate egglog by reimplementing those projects in egglog. The resulting systems in egglog are faster, simpler, and fix bugs found in the original systems.Comment: PLDI 202

Contribution of hydrogen sulfide to the control of coronary blood flow

This study examined the mechanisms by which H2S modulates coronary microvascular resistance and myocardial perfusion at rest and in response to cardiac ischemia. Experiments were conducted in isolated coronary arteries and in open-chest anesthetized dogs. We found that the H2S substrate L-cysteine (1-10 mM) did not alter coronary tone of isolated arteries in vitro or coronary blood flow in vivo. In contrast, intracoronary (ic) H2S (0.1-3 mM) increased coronary flow from 0.49 ± 0.08 to 2.65 ± 0.13 ml/min/g (P□0.001). This increase in flow was unaffected by inhibition of Kv channels with 4-aminopyridine (P=0.127) but was attenuated (0.23 ± 0.02 to 1.13 ± 0.13 ml/min/g) by the KATP channel antagonist glibenclamide (P□0.001). Inhibition of NO synthesis (L-NAME) did not attenuate coronary responses to H2S. Immunohistochemistry revealed expression of cystathionine gamma-lyase (CSE), an endogenous H2S enzyme, in myocardium. Inhibition of CSE with β-cyano-L-alanine (10 µM) had no effect on baseline coronary flow or responses to a 15 sec coronary occlusion (P=0.82). These findings demonstrate that exogenous H2S induces potent, endothelial-independent dilation of the coronary microcirculation predominantly through the activation of KATP channels, however, our data do not support a functional role for endogenous H2S in the regulation of coronary microvascular resistance

Effect of hyperfine structure on atomic frequency combs in Pr:YSO

Quantum memory will be a key component in future quantum networks, and atomic frequency combs (AFCs) in rare-earth-doped crystals are one promising platform for realizing this technology. We theoretically and experimentally investigate the formation of AFCs in Pr3+:Y2SiO5, with an overall bandwidth of 120 MHz and tooth spacing ranging from 0.1 MHz to 20 MHz, showing agreement between our calculations and measurements. We observe that the echo efficiency depends crucially on the AFC tooth spacing. Our results suggest approaches to developing a high-efficiency AFC quantum memory.Comment: 20 pages, 7 figure

Zero-G Operable Interplanetary Delivery Based Ergonomics Grabber (ZOIDBERG)

The collection and storage of float samples without cross contamination is one of many challenges facing the National Aeronautics and Space Administration (NASA). The proposed tool will be able to retrieve rock samples with a series of sample collection clamshells attached to a rotating belt positioned on a shaft. There will be one clamshell per sample collection sight. The tool will meet all safety requirements and be able to retrieve the samples without compromising the integrity of the surrounding area. After thorough design review, a prototype will be tested at the Neutral Buoyance Lab (NBL) at NASA’s Johnson Spaceflight Center in Houston, TX the first week of June. Feedback from the test will provide a foundation for future improvements to the design and operation of the device. Prior and post testing to the NBL tests will be key for precise design, fabrication, and operation. In the future, NASA may be able to use this tool to collect rock samples during asteroid missions