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Abstract We report the detection of 21 cm emission at an average redshift $\overline{z}=2.3$in the cross-correlation of data from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) with measurements of the Lyαforest from eBOSS. Data collected by CHIME over 88 days in the 400–500 MHz frequency band (1.8 <z< 2.5) are formed into maps of the sky and high-pass delay filtered to suppress the foreground power, corresponding to removing cosmological scales withk_∥≲ 0.13 Mpc⁻¹at the average redshift. Line-of-sight spectra to the eBOSS background quasar locations are extracted from the CHIME maps and combined with the Lyαforest flux transmission spectra to estimate the 21 cm–Lyαcross-correlation function. Fitting a simulation-derived template function to this measurement results in a 9σdetection significance. The coherent accumulation of the signal through cross-correlation is sufficient to enable a detection despite excess variance from foreground residuals ∼6–10 times brighter than the expected thermal noise level in the correlation function. These results are the highest-redshift measurement of 21 cm emission to date, and they set the stage for future 21 cm intensity mapping analyses atz> 1.8. 

Abstract Localizing fast radio bursts (FRBs) to their host galaxies is an essential step to better understanding their origins and using them as cosmic probes. The Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB Outriggers program aims to add very long baseline interferometry localization capabilities to CHIME, such that FRBs may be localized to tens of milliarcsecond precision at the time of their discovery, more than sufficient for host galaxy identification. The first-built outrigger telescope is theOutrigger (KKO), located 66 km west of CHIME. Cross-correlating KKO with CHIME can achieve arcsecond precision along the baseline axis while avoiding the worst effects of the ionosphere. Since the CHIME–KKO baseline is mostly east/west, this improvement is mostly in right ascension. This paper presents measurements of KKO’s performance throughout its commissioning phase, as well as a summary of its design and function. We demonstrate KKO’s capabilities as a standalone instrument by producing full-sky images, mapping the angular and frequency structure of the primary beam, and measuring feed positions. To demonstrate the localization capabilities of the CHIME–KKO baseline, we collected five separate observations each, for a set of 20 bright pulsars, and aimed to measure their positions to within 5″. All of these pulses were successfully localized to within this specification. The next two outriggers are expected to be commissioned in 2024 and will enable subarcsecond localizations for approximately hundreds of FRBs each year. 

Abstract COVID‐19 has highlighted a brutal reality known for decades, that Black, Indigenous, and People of Color bear a disproportionate burden of US annual sepsis cases. While plentiful research funds have been spent investigating genetic reasons for racial disparities in sepsis, an abundance of research shows that sepsis incidence and mortality maps to indicators of colonial practices including residential segregation, economic and marginalization sepsis, and denial of care. Here we argue that sepsis risk is an immunological embodiment of racism in colonial states, that the factors contributing to sepsis disparities are insidious and systemic. We show that regardless of causative pathogen, or host ancestry, racialized people get and die of sepsis most frequently in a pattern repeatedly reiterated worldwide. Lastly, we argue that while alleviation of sepsis disparities requires radical, multiscale intervention, biological anthropologists have a responsibility in this crisis. While some of us can harness our expertise to take on the ground action in sepsis prevention, all of us can leverage our positions as the first point of contact for in depth human biology instruction on most college campuses. As a leading cause of death worldwide, and a syndrome that exhibits the interplay between human physiology, race and environment, sepsis is at the nexus of major themes in biological anthropology and is a natural fit for the field's curriculum. In adopting a discussion of race and sepsis in our courses, we not only develop new research areas but increase public awareness of both sepsis and the factors contributing to uneven sepsis burden.