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We explore the properties of interferometric data from high-redshift 21 cm measurements using the Murchison Widefield Array (MWA). These data contain the redshifted 21 cm signal, contamination from continuum foreground sources, and radiometric noise. The 21 cm signal from the Epoch of Reionization (EoR) is expected to be highly Gaussian, which motivates the use of the power spectrum as an effective statistical tool for extracting astrophysical information. We find that foreground contamination introduces non-Gaussianity into the distribution of measurements and then use this information to separate Gaussian from the non-Gaussian signal. We present improved upper limits on the 21 cm EoR power spectrum from the MWA using a Gaussian component of the data, based on the existing analysis from C. D. Nunhokee et al. 2025. This is extracted as the best-fitting Gaussian to the measured data. Our best 2σ (thermal+sample variance) limit for 268 hr of data improves from (30.2 mK)2 to (23.0 mK)2 at z = 6.5 for the East–West polarization, and from (39.2 mK)2 to (21.7 mK)2 = 470 mK2 in North–South. The best limits at z = 6.8 (z = 7.0) improve to P < (25.9 mK)2 (P < (32.0 mK)2) and k = 0.18h Mpc‑1 (k = 0.21h Mpc‑1). Results are compared with realistic simulations, which indicate that leakage from foreground contamination is a source of the non-Gaussian behavior. 

This paper presents the spherically averaged 21 cm power spectrum derived from Epoch of Reionization (EoR) observations conducted with the Murchison Widefield Array (MWA). The analysis uses EoR0-field data, centered at (R.A. = 0h, decl. = ‑27∘), collected between 2013 and 2023. Building on the improved methodology described in C. M. Trott et al. (2024), we incorporate additional data quality control techniques introduced in C. D. Nunhokee (2020). We report the lowest-power-level limits on the EoR power spectrum at redshifts z = 6.5, z = 6.8, and z = 7.0. These power levels, measured in the east–west polarization, are (30.2)2 mK2 at k = 0.18 h Mpc‑1, (31.2)2 mK2 at k = 0.18 h Mpc‑1, and (39.1)2 mK2 at k = 0.21 h Mpc‑1, respectively. The total integration time amounts to 268 hr. These results represent the deepest upper limits achieved by the MWA to date and provide the first evidence of the heated intergalactic medium at redshifts z = 6.5 to 7.0. 

Students from underrepresented populations—females, working class, and youth from marginalized racial/ethnic groups—are less likely than their middle-class Asian and White male peers to study computer science (CS) in college. The dearth of CS undergraduates from these groups contributes to projected labor force shortages. Sources of the dilemma include weak or absent inspiration and CS preparation in middle schools and negative stereotypes suggesting certain groups do not belong in CS. This case study describes three years of a community collaboration between a local university and a nearby middle school attended by primarily low-income students of color. The University of North Carolina Charlotte/Wilson STEM Academy Partnership focused on undergraduates majoring in CS teaching monthly workshops designed to inspire and academically prepare the middle schoolers for college and CS majors by teaching them coding and computational thinking while also challenging stereotypes about who belongs in CS. Post-workshop assessments, reflective essays, interviews, and administrative data were thematically coded. Findings suggest the workshops sparked interest in college and CS, undermined toxic stereotypes, and nurtured the academic self-confidence of middle schoolers. The Partnership provided the undergraduates with opportunities to meet their own academic goals while “paying it forward.” Results suggest that the Partnership can serve as a model starting point for disrupting the disproportionalities in female and underrepresented minority students in CS. 

The geographical ranges of many mammals and their associated parasites are dynamic. Comprehensive documentation of these communities over time provides a foundation for interpreting how changing environmental conditions, driven by accelerating climate change, other anthropogenic disturbances, and natural events, may influence host-parasite interactions. Fleas (Order Siphonaptera) are obligate, hematophagous parasites of birds and mammals with medical interest because of their role in transmitting pathogens. From 2016 to 2019, we sampled the small mammal and associated flea communities in El Malpais National Conservation Area (El Malpais) in Cibola County, New Mexico. Among 898 mammalian specimens, 925 fleas representing 29 species were collected from 18 host species. Pleochaetis exilis was the most abundant flea species, composing 27% of the total fleas collected, whereas Aetheca wagneri was the most prevalent flea species, parasitizing 8% of the community sampled. Across a total of 284 hosts recorded with fleas, A. wagneri, Malaraeus eremicus, and Peromyscopsylla hesperomys adelpha parasitized the most host species (n = 6 each). Onychomys leucogaster (Wied-Neuwied, 1841), the northern grasshopper mouse, a rodent highly implicated in plague dynamics, was host for the highest number of flea species (n = 15), followed by Peromyscus truei (Shufeldt, 1885) (n = 10). Our aims are to (a) describe the flea-mammal assemblage of a central New Mexico site, creating a baseline for diversity against which changing patterns of association can be assessed over time; (b) identify previously unrecognized host associations; and (c) examine infestation parameters, including the relationships of flea prevalence and mean abundance to host sex, host abundance, and seasonality. As such, our study exemplifies the Documentation and Assessment phases of the DAMA protocol (Document, Assess, Monitor, Act), a central component of exploring distribution and diversity of complex pathogen-host communities across space and time that are essential to a proactive understanding of emerging disease.