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On 2020 September 18 U.S. Government (USG) sensors detected a bolide with peak bolometric magnitude of −19 over the Western Pacific. The impact was also detected by the Geostationary Lightning Mapper instrument on the GOES-17 satellite and infrasound sensors in Hawaii. The USG measurements reported a steep entry angle of 67° from horizontal from a radiant 13° east of north and an impact speed of 11.7 km s ^−1 . Interpretation of all energy yields produces a preferred energy estimate of 0.4 kt TNT, corresponding to a 23,000 kg, 3 m diameter meteoroid. A postimpact search of telescopic images found that the Asteroid Terrestrial-impact Last Alert System survey captured the object just 10 minutes prior to impact at an Earth-centered distance of nearly 11,900 km with apparent magnitude m = 12.5. The object appears as a 0.44° streak originating on the eastern edge of the image, extending one-third of the USG state-vector-based prediction of 1.26° over the 30 s exposure. The streak shows brightness variability consistent with small asteroid rotation. The position of Earth’s shadow, the object’s size, and its consistency with the reported USG state vector confirm the object is likely natural. This is the eighth preatmospheric detection of a near-Earth asteroid (NEA) impactor and the closest initial telescopic detection prior to impact. The high altitude of peak fireball brightness suggests it was a weak object comparable in many respects with 2008 TC3 (the Almahata Sitta meteorite), with an absolute magnitude H = 32.5 and likely low albedo. Therefore, we suggest the NEA was a C-complex asteroid.

By applying a salt metathesis approach between Ce(OtBu3)2(NO3)2(THF)2 and the potassium salts of mono- and ditrimethylsilyl substituted cyclopentadienes, we were able to isolate two new Ce(IV) metallocenes, including to the best of our knowledge, the first structurally characterized bis-cyclopentadiene Ce(IV) compound.

To quantify the minimum magnetic resonance imaging (MRI) spatial resolution of the visible deoxygenated microscopic vessels of the human brain at 8 T. This study compared 8-T gradient echo (GE) images of a human cadaver brain having an in-plane resolution of 195 × 195 μm to corresponding digital photographs of 205 cryomicrotome sections of the same cadaver brain, along with summed images of 25 contiguous cryomicrotome sections. One-millimeter-thick GE images of a 1-cm-thick unfixed whole coronal brain section were acquired using techniques similar to those commonly utilized for 8-T human imaging in vivo. There was excellent MR visualization of the deoxygenated microscopic vessels within the brain down to a resolution of approximately 100 μm. By taking advantage of magnetic susceptibility-based blood oxygenation level-dependent (BOLD) contrast, deoxygenated microscopic blood vessels smaller than the pixel dimensions used for imaging can be visualized using a whole-body 8-T MRI system. J. Magn. Reson. Imaging 2004;19:303–307. © 2004 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Discusses a work-in-progress on Immanuel Kant's late writings, a part of which reads Kant and Thomas De Quincey alongside each other. De Quincey's response to ways in which Kant had begun to reimagine himself; De Quincey's translation, ventriloquization and recirculation of Ehregott Andreas Christoph Wasianski's first-hand recollections of the life of Kant; Model of an alternative way of knowing.

Historical Research and Cataloging Using a Combination of Portable TRS-80 Model 100 and the Pick Database System on an IBM-XT