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On Linear Invariants of Hypergraphs
No full textWe introduce linear invariants of hypergraphs as a way to study hypergraphs by their tensor representations. Our primary research goal is to determine what information linear invariants capture about the hypergraphs they arise from. We first investigate the centroid, which is shown to determine the connected components of a hypergraph. Next, we study the derivations of a hypergraph, and use this linear invariant to define a quotient operator on the collection of all hypergraphs. This operator is shown to be a closure operator in that for any hypergraph . We apply the operator to synthetically generated hypergraphs, exploring what features of a hypergraph it detects, and we discuss how this operator could be applied to hypergraphs arising from real data
Computationally Modeling Standard Space Frames and Origami Inspired Frames: A Comparative Analysis
No full textSpace structures, including space frames or space trusses depending on the type of connections, are a three-dimensional structure made of interconnected members that are often used for roof supporting systems. These structures can distribute loads in three dimensions and support wide spans without the need for many intermediate supports. Deployable structures are systems that can be folded for easy disassembly and transportation, and then can be simply “deployed” for their desired purpose.
A space structure inspired by the geometry of the Miura-Ori origami fold, referred to as the origami frame or truss, was computationally modeled. This was done to create a space structure system that has inherent folding ability, allowing for a wide range of future applications as a deployable structure. This study aimed to compare a standard space truss with the origami truss by evaluating the structural performance of both trusses in terms of geometrical properties, load capacity, and deflection. The goal of this study was to conclude if the origami truss was feasible as compared to the standard space truss, in order to allow for future studies into its fabrication, specifically noting its advantage of deployability.
The origami truss was found to have both advantages and disadvantages as compared to the space truss. Advantages include requiring fewer members to cover a given span, correlating to the self-weight of the structure, and a decrease in complexity of the connections. Additionally, it was found that the total load capacities of the structures are essentially equal. Disadvantages of the origami truss include a greater deflection and number of required connections for a given span. Despite the drawbacks, the origami truss is concluded to be a viable structure that needs further investigations to understand the limitations that would need to be placed on it for use in practice
The Influence of Polycyclic Aromatic Hydrocarbons on the Reactivity of Fatty Acids when Exposed to Chlorine Bleach Vapor
No full textThe COVID-19 pandemic led to an increase in use of disinfectants such as chlorine bleach in indoor environments, which releases hypochlorous acid (HOCl) and chlorine (Cl2) gases when applied to a surface. HOCl and Cl2 can undergo multiphase oxidation and chlorination reactions with olefinic compounds like fatty acids (FAs) that are found on indoor surfaces and human skin. However, the additional components on skin surfaces and in the air could influence the identities of products formed and their formation rates. Due to wildfires and fossil fuel combustion, many people are exposed to combustion-sourced compounds like polycyclic aromatic hydrocarbons (PAHs) and phenolics, which may influence how FAs react with reactive gases. To investigate multicomponent reactions between bleach vapor and FAs, films of oleic acid (OA) with and without PAHs were prepared on glass circle slides that were then placed in a glass flow tube reactor under bleach vapor exposure. Oxidation and chlorination products were characterized using liquid chromatography – mass spectrometry (LC-MS) and relative quantification was performed to compare experimental cases. The effectiveness of the PAH as a photosensitizer in the mixture affected the OA decay rate. At low levels of HOCl/Cl2 exposure, the addition of benzo[a]pyrene to OA films enhanced the formation of dimeric OA esters compared to pure OA films, while the addition of phenanthrene did not. Literature indicates that oxidized PAHs tend to increase the inherent oxidative potential of solutions and surfaces via quinone formation, which we hypothesized would influence OA oxidation to a greater effect than the parent PAHs. Heightened oxidative potential represents a larger volume of reactive oxygen species, yielding additional oxidants in the surface films. Thus, the addition of phenanthrenequinone to the sample was investigated. PhenQuin increased the rate constant of OA decay by roughly 3x more than Phen and pure OA but showed an OA decay rate constant similar to when BaP was added to the surface film. These findings demonstrate that the presence and identity of combustion-sourced compounds modulate the chemical reactivity of a monounsaturated fatty acid under bleach vapor exposure. Oxidized PAHs, like phenanthrenequinone, can enhance secondary oxidant generation within the film and thus fatty acid degradation. PAH influence over OA reactivity highlights the importance of considering complex surface and gas-phase mixtures when evaluating multiphase indoor chemistry because the interaction between certain cleaning agents and pollutants could lead to the formation of unexpected and potentially harmful by-products
Femmephobia & the Mental Load in Academia
No full textIn this article, I extend the existing theoretical foundation on the mental load to the realm of academia. Using autoethnographic analysis paired with femme theory (Hoskin 2017), I argue that my experience of the mental load within academia distinctly illustrates the denigration of femininity and feminine traits while simultaneously relying upon them for the success and functionality of the workplace. As a result of sharing these autoethnographic vignettes and highlighting these experiences, I advocate for mechanisms to intervene into these phenomena, which impact the professional climate and experience for feminized academics. Ultimately, I highlight a few immediate practical applications for examining our own work cultures and advocating for cultures that are less femmephobic and which more readily recognize the value and contributions of feminized labor including the critical role of the mental load
Resilience in African History
Full text linkBetween 1960, when seventeen African countries gained independence from French colonial rule, and 2020, when the global pandemic of Covid-19 emerged, just over five hundred scholarly books or articles were published addressing, to varying degrees, resilience on the African continent. Working toward this special issue has made it clear that there continues to be a great deal of slippage in how scholars describe resilience. This concept is often conflated with terms such as “resistance,” “persistence,” and “endurance.” While these do express ways humans respond to adversity, they are distinct from resilience, which is rooted in adaptation not opposition.1 Some people choose counterviolence or confrontation as the path toward adaptation; however, resilience is not an exact synonym for those other terms. The definitional slippage may result from scholars perceiving resilience to be the inverse of vulnerability and the antidote to collapse or as an answer to the neoliberal need for individual responsibility
Transformer-Based Symbolic Music Generation
Full text linkThis thesis investigates the capacity of transformer-based architectures to learn generalized musical patterns through symbolic generation. To support this exploration, a complete music generation pipeline was developed, beginning with the construction and classification of a large-scale dataset of over 170,000 MIDI files. The dataset was processed using rule-based heuristics and custom neural classifiers to separate tracks by musical function and contour. A novel tokenization scheme, MINTii, was introduced to encode musical information compactly through interval-based representations, reducing redundancy and promoting generalization. Using this infrastructure, a transformer model was trained to generate single-track melodic sequences. Its performance was evaluated through both memorization and generalization tests. While harmonic tendencies such as pitch motion and range were learned with moderate success, rhythmic understanding remained limited. Further analysis revealed that the model could not reproduce even short, repeated sequences under ideal conditions, highlighting structural limitations in learning temporal phrasing. These findings suggest that fully data-driven transformer models lack the inductive bias needed to internalize musical form, and that future systems may benefit from rule-based constraints, structural labeling, or loss functions grounded in music theory
Social Factors Variably Predict Salivary Cortisol Levels in Tufted Capuchins
Full text linkGlucocorticoids (GCs) have become a prime focus in studies involving the relationship between psychosocial factors and physiology. For social animals, determining the social variables that relate to both GC release and buffering can help tease apart the complex interplay between the psychological and physiological dynamics of individuals and their communities. A 2019 study found relationships between social factors and hair cortisol in a group of socially housed tufted capuchin monkeys in which social support correlated negatively with cortisol levels while received aggression correlated positively. The present study examined the relationships between similar social measures and salivary cortisol in the same group of capuchin monkeys to test whether these relationships remain constant over time and in different biological matrices. Salivary samples were collected from the group in 2022 and 2023 and median and standard deviation (SD) of GC release were calculated and compared to four social measures of interest (dominance rank, aggression received, social network centrality, and grooming received) which were derived from long-term behavioral observations of the group. SD in 2022 was predicted by two social measures, social network centrality and aggression received, consistent with the results of the previous study, but neither SD in 2023 nor medians of either year were predicted by any social measures. Though methodological differences between this and the previous study may explain the lack of consistency in findings, I highlight the importance of considering changing social dynamics as a significant factor affecting socio-physiological relationships. Additionally, the potential association between long term cortisol exposure and short term cortisol variability is discussed
The History of Celiac Disease Legislation, and How Public Perception can Impact its Future
No full textThe Impact of Drying Additives on Selective Polymorph Crystallization of Acetaminophen
No full textPharmaceutical drug delivery strongly depends on the solid-state packing of the active pharmaceutical ingredient (API) within a pill or tablet. However, many drugs can form multiple different packing crystal structures, or polymorphs, that are difficult to predict and control. These polymorphs may have different properties such as compressibility, bioavailability, and solubility, which may significantly impact drug pharmacokinetics. Thus, polymorph selectivity has become a vital part of the pharmaceutical development and formulation process. Several factors impact selective polymorph crystallization, including environmental conditions and the use of additives in the polymorph mixture. Acetaminophen, the active ingredient in Tylenol, is an example of a polymorphic compound, with nine polymorphic forms, three of which are well characterized and form at standard temperatures and pressures. Among these three, Form III is of particular interest as it is labeled “elusive” in the literature and has not been prepared as a single crystal to date. Several variables have been proposed to control Form III crystallization, with one recent report highlighting the effectiveness of lactose in promoting Form III. This thesis explores how the model drug acetaminophen crystallizes when different sugar-based additives are present during crystallization. The success of the selective crystallization using heating-cooling cycles was determined via differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). We find that the use of multiple sugar excipients facilitate the crystallization of Form III acetaminophen, although to different extents depending on the sugar used. Fructose and sucrose are observed to have some of the best performance. Additionally, there is a shift in the onset temperature of initial crystallization when sugar additives are used; this effect is most prominent in samples containing monosaccharides. Finally, Form III crystallization with non-sugar additives was demonstrated using silica powder