icosahedral

We decided to consult the office Magic 8-Ball in finding our next raffle prize for the VCU Countdown to Classes contest. Asking if we should give it away it replied, “As I see it, yes.” 

So goodbye, Magic 8-Ball. Thanks for the years. We hope your quirky yes or no answers will help some other lucky Ram with important life decisions. 

Question #22: Will this be a great year at VCU? (Must give a Magic 8 Ball Answer)* #3daysTilVCU

Answer the Question, include the #3daysTilVCU tag and shiny, round, “Allison DuBois” may be perching on your shelf soon.

*Optional answers:

  1. It is certain
  2. It is decidedly so
  3. Without a doubt
  4. Yes - definitely
  5. You may rely on it
  6. As I see it, yes
  7. Most likely
  8. Outlook good
  9. Signs point to yes
  10. Yes
  11. Reply hazy, try again
  12. Ask again later
  13. Better not tell you now
  14. Cannot predict now
  15. Concentrate and ask again
  16. Don’t count on it
  17. My reply is no
  18. My sources say no
  19. Outlook not so good
  20. Very doubtful
Thirty-Three Polyhedra with Icosidodecahedral Symmetry

Note:  icosidodecahedral symmetry, a term coined (as far as I know) by George Hart, means exactly the same thing as icosahedral symmetry. I simply use the term I like better. Also, a few of these, but not many, are chiral.

The images directly above and below show the shape of the most symmetrical 240-carbon-atom fullerene.

The image above is of the compound of five tetrahedra. This…

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Samstag noch ungewiss

Während die Wetterdienste für Sonntag einig sind, dass es regnerisch werden soll, herrscht für Samstag noch Ungewissheit. Nehmen wir Garmisch-Partenkirchen als Beispiel. Die Bandbreite reicht von 8 Stunden Sonne (kein Regen) bei meteomedia bis lediglich 2 Stunden (40% Regenwahrscheinlichkeit) bei wetteronline.

So sind auch die numerischen Wetterprognose-Modelle uneins. Während ICON (icosahedral non-hydrostatic global circulation model) und GFS (Global Forecast System) für Samstag ein Feuchtefeld über Süddeutschland zeigen, taucht dies im neuesten Lauf von ECMW (Europäisches Zentrum für mittelfristige Wettervorhersagen) nicht mehr so ausgeprägt auf. Was den Zug des Tiefs betrifft, das in der Nacht Samstag/ Sonntag von den Britischen Inseln nach Deutschland ziehen soll, berechnet GFS einen schnelleren Ablauf als die beiden anderen Modelle. (Quelle: Deutscher Wetterdienst)

Asymmetric Genome Organization in an #RNA Virus Revealed via Graph-Theoretical Analysis of Tomographic Data

by James A. Geraets, Eric C. Dykeman, Peter G. Stockley, Neil A. Ranson, Reidun Twarock Cryo-electron microscopy permits 3-D structures of viral pathogens to be determined in remarkable detail. In particular, the protein containers encapsulating viral genomes have been determined to high resolution using symmetry averaging techniques that exploit the icosahedral architecture seen in many viruses. By contrast, structure determination of asymmetric components remains a challenge, and novel analysis methods are required to reveal such features and characterize their functional roles during infection. Motivated by the important, cooperative roles of viral genomes in the assembly of single-stranded #RNA viruses, we have developed a new analysis method that reveals the asymmetric structural organization of viral genomes in proximity to the capsid in such viruses. The method uses geometric constraints on genome organization, formulated based on knowledge of icosahedrally-averaged reconstructions and the roles of the #RNA-capsid protein contacts, to analyse cryo-electron tomographic data. We apply this method to the low-resolution tomographic data of a model virus and infer the unique asymmetric organization of its genome in contact with the protein shell of the capsid. This opens unprecedented opportunities to analyse viral genomes, revealing conserved structural features and mechanisms that can be targeted in antiviral drug design.http://bit.ly/1HaohHs #PLoS