Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Contributing student pedagogy

<p>A Contributing Student Pedagogy (CSP) is a pedagogy that encourages students to contribute to the learning of others and to value the contributions of others. CSP in formal education is anticipatory of learning processes found in industry and research, in which the roles and responsibilities of 'teacher' and 'student' are fluid. Preparing students for this shift is one motivation for use of CSP. Further, CSP approaches are linked to constructivist and community theories of learning, and provide opportunities to engage students more deeply in subject material.</p> <p>In this paper we advance the concept of CSP and relate it to the particular needs of computer science. We present a number of characteristics of this approach, and use case studies from the available literature to illustrate these characteristics in practice. We discuss enabling technologies, provide guidance to instructors who would like to incorporate this approach in their teaching, and suggest some future directions for the study and evaluation of this technique. We conclude with an extensive bibliography of related research and case studies which exhibit elements of CSP.</p&gt

“Astonishing successes” and “bitter disappointment”: The specific heat of hydrogen in quantum theory

The specific heat of hydrogen gas at low temperatures was first measured in 1912 by Arnold Eucken in Walther Nernst’s laboratory in Berlin, and provided one of the earliest experimental supports for the new quantum theory. Even earlier, Nernst had developed a quantum theory of rotating diatomic gas molecules that figured in the discussions at the first Solvay conference in late 1911. Between 1913 and 1925, Albert Einstein, Paul Ehrenfest, Max Planck, Fritz Reiche, and Erwin Schrödinger, among many others, attempted theoretical descriptions of the rotational specific heat of hydrogen, with only limited success. Quantum theory also was central to the study of molecular spectra, where initially it was more successful. Moreover, the two problems interacted in sometimes surprising ways. Not until 1927, following Werner Heisenberg’s discovery of the behavior of indistinguishable particles in modern quantum mechanics, did American theorist David Dennison find a successful theory of the specific heat of hydrogen