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FRAGMENT FROM NATURE for this and next weekend focuses on a stunning Russian publication documenting microorganisms collected from the outside of the International Space Station during a spacewalk. Unlike their American counterparts, the Russians have maintained a strong public interest in exploring life in space, and this is an extremely important publication. The samples were collected in 2013, and the publication came out in 2018. View in LinkedIn

STRATOSPHERIC ORGANISMS. “Aerobiological studies have also shown the existence of active and dormant forms of bacterial and fungal spores in the stratosphere, for example, Micrococcus luteum, Mycobacterium albus, Circinella muscae, Aspergillus niger, Papulaspora anomala, Penicillium notatum; Bacillus simplex, Staphylococcus pasteuri, Engyodontium album; Deinococcus aetherius; and Bacillus isronensis.” https://lnkd.in/dNHWs6R View in LinkedIn

Limestone marker of lost significance near the Girona cathedral. View in LinkedIn

LICHENS SURVIVED 1.5 YEARS IN SPACE. “Thus Antarctic rocks colonized by lichens and fungi (Stihosotskus sp. and Acarospora sp.) were placed for 1.5 years on the ISS, simulating conditions on Mars, and then investigated by molecular methods. It was determined that extraterrestrial ultraviolet (UV) emission of sun (λ ≥ 110 nm) and also Martian UV (λ ≥ 200 nm) are the most harmful factors. However, even after such treatment, there remained a small percentage of live spores.” https://lnkd.in/dNHWs6R View in LinkedIn

INHERITABILITY. “Phenotypic traits like body size and shape typically exhibit a substantial degree of “phylogenetic signal,” meaning that they are inherited, and the phenotypes of closely related species are strongly correlated.” https://lnkd.in/dwfZQzE View in LinkedIn

PROBABILITY CURVES. “By using a Brownian motion model for the evolution of continuous traits, the maximum-likelihood value was estimated for each neural network parameter at each node. The neural network model was used to produce the shells using the estimated parameters for each node. Color is not part of the neural network model, so it was added independently to the models of living shells, and then mapped onto the phylogeny (using maximum likelihood) as a binary trait (black/white or brown/white).” https://lnkd.in/dwfZQzE View in LinkedIn

COMPUTER MODEL. “Fig. 4. Maximum-likelihood estimates of ancestral shell patterns. Shells of living species are displayed at the tips; to the right of these are shells “grown” in the computer by using the neural-network model and the fitted parameters. https://lnkd.in/dwfZQzE View in LinkedIn

THE ISSUE OF PATTERN MEMORY. “Morphogen models described by diffusion-reaction dynamics unfold with no “memory” of the system state other than the current state. The neural model, however, is a sensory feedback system in which the current secretion depends on sensing the history of the pattern before the current state.” https://lnkd.in/dwfZQzE View in LinkedIn

NEURAL MODELS. “Also, as the neural models are more general, they can generate a wider variety of patterns than can diffusible morphogen models. One other difference is fundamental.” https://lnkd.in/dwfZQzE View in LinkedIn

FRAGMENT FROM NATURE. Due to a computer malfunction, this second part of the weekend cone shell patterning fragment from a week ago was not available, so it will be inserted here to complete the series. View in LinkedIn