Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

Investigation of Materials used by Edvard Munch

The pigments and paint binders used by Edvard Munch have been investigated in several studies. Munch used a mixture of media in his works of art. The two versions of The Scream studied here were found to include oil paints and oil paints thickened with beeswax and also oil crayons containing beeswax and Japan wax, as well as casein pastels, a paraffin wax crayon and at least one gum-bound paint. His sketches on canvas make use of oil paints and tempera paints including egg and casein, as well as casein pastels in at least one instance. His oil paintings on canvas seem to have been executed using a more conventional technique, with most having one or a few paint layers bound with linseed oil on a ground formed from lead white in oil on top of a ground made of chalk in glue. Munch's palette is not extensive, though he was reasonably willing to introduce new materials, such as his use of a petroleum-based wax crayon in 1893, oil pastel - possibly as early as 1893 and certainly by 1910, and his use of cadmium red by 1927-1929. The identification of materials has informed conservators who are planning and carrying out conservation treatment

Pore Formation During Solidification of Aluminum: Reconciliation of Experimental Observations, Modeling Assumptions, and Classical Nucleation Theory

An in-depth discussion of pore formation is presented in this paper by first reinterpreting in situ observations reported in the literature as well as assumptions commonly made to model pore formation in aluminum castings. The physics of pore formation is reviewed through theoretical fracture pressure calculations based on classical nucleation theory for homogeneous and heterogeneous nucleation, with and without dissolved gas, i.e., hydrogen. Based on the fracture pressure for aluminum, critical pore size and the corresponding probability of vacancies clustering to form that size have been calculated using thermodynamic data reported in the literature. Calculations show that it is impossible for a pore to nucleate either homogeneously or heterogeneously in aluminum, even with dissolved hydrogen. The formation of pores in aluminum castings can only be explained by inflation of entrained surface oxide films (bifilms) under reduced pressure and/or with dissolved gas, which involves only growth, avoiding any nucleation problem. This mechanism is consistent with the reinterpretations of in situ observations as well as the assumptions made in the literature to model pore formation