Gujba: A new Bencubbin-like meteorite fall from Nigeria

Gujba is a new Bencubbin-like meteorite fall enriched in N-15 and consisting (in vol.%) of 41% metal nodules, 20% large light-colored silicate nodules and 39% dark-colored, C- and silicate-rich matrix

Abundances of the elements in the solar system

A review of the abundances and condensation temperatures of the elements and their nuclides in the solar nebula and in chondritic meteorites. Abundances of the elements in some neighboring stars are also discussed.Comment: 42 pages, 11 tables, 8 figures, chapter, In Landolt- B\"ornstein, New Series, Vol. VI/4B, Chap. 4.4, J.E. Tr\"umper (ed.), Berlin, Heidelberg, New York: Springer-Verlag, p. 560-63

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Lithium in tektites and impact glasses: Implications for sources, histories and large impacts

Lithium (Li) abundances and isotope compositions were determined in a representative suite of tektites (moldavites, Muong Nong-type tektites and an australite, Ivory Coast tektites and bediasites), impact-related glasses (Libyan Desert Glass, zhamanshinites and irghizites), a glass fragment embedded in the suevite from the Ries impact crater and sedimentary materials in order to test a possible susceptibility of Li to fractionation during hypervelocity impact events and to de-convolve links to their potential parental sources. The overall data show a large spread in Li abundance (4.7–58 ppm Li) and δ7Li values (−3.2‰ to 26.0‰) but individual groups of tektites and impact glasses have distinctive Li compositions

Beryllium-10 in Australasian tektites: constraints on the location of the source crater

By using accelerator mass spectrometry we have measured the Be- 10 concentrations of 86 Australasian tektites. Corrected to the time of tektite production similar to0.8 My ago, the Be-10 concentrations (10(6) atom/g) range from 59 for a layered tektite from Huai Sai, Thailand, to 280 for an australite from New South Wales, Australia. The average value is 143 +/- 50. When tektites are sorted by country, their average measured Be- 10, concentrations increase slowly with increasing distance from Southeast Asia, the probable location of the tektite producing event, from 59 +/- 9 for 6 layered tektites from Laos to 136 +/- 20 for 20 splash-form tektites from Australia. The lowest Be-10 concentrations for tektites fall on or within a contour centered off the shore of Vietnam, south of the Gulf of Tonkin (107degreesE; 17degreesN), but also encompassing two other locations in the area of northeastern Thailand previously proposed for the site of a single tektite-producing impact. The Be-10 concentrations of layered tektites show only a weak anticorrelation (R similar to -0.3) with the numbers of relief crystalline inclusions. Loosely consolidated, fine-grained terrestrial sediments or recently consolidated sedimentary rocks are the most likely precursor materials. Dilution of sediments with other kinds of rock raises problems in mixing and is not supported by petrographic data. Sedimentary columns that have the right range of Be-10 concentrations occur off the coasts of places where sedimentation rates are high relative to those in the deep sea. A single impact into such a region, 15 to 300 m thick, could have propelled near-surface, high-Be-10 material farthest-to Australia-while keeping the deeper-lying, low-Be-10 layers closer to home. We do not rule out, however, other proposed mechanisms for tektite formation