Browsing by Author "Bell, Elizabeth A."

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    A failed search for concordancy across multiple isotopic systems in lunar impactites: Implications for testing the Late Heavy Bombardment hypothesis
    (Elsevier, 2024) Harrison, T. Mark; Zhang, Bidong; Parisi, Andrew F.; Bell, Elizabeth A.
    Investigations of Apollo-returned samples radically altered our understanding of lunar history which has important implications for terrestrial habitability and Solar System evolution. Radiometric dating of those samples inspired the hypothesis that Moon experienced a Late Heavy Bombardment (LHB) at ∼3.9 Ga. The LHB concept has come under several recent challenges, including the concern that 40Ar/39Ar step-heating dates of Apollo impactites had been misinterpreted. Ultraviolet laser ablation (UVLAMP) 40Ar/39Ar dates – with their capacity for much higher spatial resolution and thus potential to avoid dating near-ubiquitous clasts in impact melt rocks – should in principle provide more interpretable results. Here we compare new ion microprobe 207Pb/206Pb accessory mineral dates for two Apollo 17 impactites for which UVLAMP 40Ar/39Ar dates had been previously obtained. Our results are consistent with a single accessory phase growth event for each sample, though the two samples yielded statistically different mean ages of ca. 3.974±0.013 and 3.928±0.003 Ga. Both can reasonably be interpreted as dating an impact event, but the 207Pb/206Pb dates are older than the associated 40Ar/39Ar dates by several hundred million years. We interpret that the age differences result from subsequent thermal disturbances. The discordancy between impact ages inferred from lunar impactites using two different radiometric systems suggests caution in acceptance of the LHB hypothesis without the benefit of both larger lunar datasets and more multichronometric studies. Even with such information, our capacity to know the lunar bombardment history is likely limited by compositional and thermal effects which appear to restrict growth of impact-produced accessory minerals to a small fraction of the lunar surface. Using currently available datasets, the LHB hypothesis may be effectively untestable.
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    Enhancing team success in the neonatal intensive care unit: challenges and opportunities for fluid teams
    (Frontiers Media S.A., 2023) Bell, Elizabeth A.; Rufrano, Gabrielle A.; Traylor, Allison M.; Ohning, Bryan L.; Salas, Eduardo
    Fluid teams, characterized by frequent changes in team membership, are vital in the neonatal intensive care unit (NICU) due to high patient acuity and the need for a wide range of specialized providers. However, many challenges can hinder effective teamwork in this setting. This article reviews the challenges related to fluid teamwork in the NICU and discusses recommendations from team science to address each challenge. Drawing from the current literature, this paper outlines three challenges that can hinder fluid teamwork in the NICU: incorporating patient families, managing hierarchy among team members, and facilitating effective patient handoffs. The review concludes with recommendations for managing NICU teamwork differently using strategies from team science.