Publications by authors named "W A Clyde"

We investigate the effectiveness of seven government containment and policy closure interventions against the novel coronavirus (SARS-COV-2) pandemic in the OECD countries, at several different time horizons. Our results indicate that only school closings and public transportation closings have a persistently significant impact. Stay-at-home policies only show a significant impact after 70 days.

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We report a time-calibrated stratigraphic section in Colorado that contains unusually complete fossils of mammals, reptiles, and plants and elucidates the drivers and tempo of biotic recovery during the poorly known first million years after the Cretaceous-Paleogene mass extinction (KPgE). Within ~100 thousand years (ka) post-KPgE, mammalian taxonomic richness doubled, and maximum mammalian body mass increased to near pre-KPgE levels. A threefold increase in maximum mammalian body mass and dietary niche specialization occurred at ~300 ka post-KPgE, concomitant with increased megafloral standing species richness.

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Article Synopsis
  • Abrupt changes in the global carbon cycle during the early Eocene led to significant global warming events similar to today's climate change.
  • During these warming events, specifically the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM2), mammalian dwarfing was observed as a response to climate shifts.
  • The study found that during ETM2, certain mammal groups, especially early horses, showed a notable decrease in size, indicating that the degree of dwarfing correlates with the intensity of these warming events.
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Early anthropoid evolution in Afro-Arabia is poorly documented, with only a few isolated teeth known from before approximately 35 million years ago. Here we describe craniodental remains of the primitive anthropoid Biretia from approximately 37-million-year-old rocks in Egypt. Biretia is unique among early anthropoids in exhibiting evidence for nocturnality, but derived dental features shared with younger parapithecids draw this genus, and possibly >45-million-year-old Algeripithecus, into a morphologically and behaviorally diverse parapithecoid clade of great antiquity.

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