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The Perseverance rover landed in Jezero crater, Mars, to investigate ancient lake and river deposits. We report observations of the crater floor, below the crater's sedimentary delta, finding that the floor consists of igneous rocks altered by water. The lowest exposed unit, informally named Séítah, is a coarsely crystalline olivine-rich rock, which accumulated at the base of a magma body. Magnesium-iron carbonates along grain boundaries indicate reactions with carbon dioxide-rich water under water-poor conditions. Overlying Séítah is a unit informally named Máaz, which we interpret as lava flows or the chemical complement to Séítah in a layered igneous body. Voids in these rocks contain sulfates and perchlorates, likely introduced by later near-surface brine evaporation. Core samples of these rocks have been stored aboard Perseverance for potential return to Earth.

Objective: The Small Parts Test Fixture (SPTF) (16 CFR 1501) was developed from cadavers of young children and foreign body (FB) data. Recent FB studies reveal that the SPTF misses outliers. Computerized tomography (CT) provides detailed dimensional data for young children. Our null hypothesis is that the SPTF (31.75 mm) is smaller than relevant portions of the aerodigestive tract., Methods: A 3-year retrospective review (2011-2014) of head/neck CT data for infants and children (N = 106) aged 6 months to 6 years was completed. Six measurements (mm) were recorded: 1) maxillary incisors to posterior edge of hard palate (MI/HP); 2) posterior edge of hard palate to first cervical (C1) vertebra (HP/C1); 3) soft palate to posterior pharyngeal wall; and 4) interpalatine tonsillar distance; 5, 6) larynx diameter, and width. Two ratios were calculated: 1) ratio of lengths (hard palate to soft palate), and 2) laryngeal dimensional ratio., Results: A linear trend of increasing dimensions with increased age was noted. The length measured MI/HP best correlates with known data of potential FBs causing injury or death. This MI/HP length can range from 33.8 to 45.8 mm for all children younger than 3 years of age and exceeds the SPTF diameter (31.75 mm). There were no statistical anatomical differences by gender in any of the age groups., Conclusion: Computed tomography measurements appear larger than SPTF values developed from cadavers. These CT data support enlargement of the SPTF to enhance safety for choking hazards in children., Level of Evidence: 4 Laryngoscope, 129:1468-1476, 2019., (© 2018 The American Laryngological, Rhinological and Otological Society, Inc.)