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Map Challenge FAQ

Below are compiled questions/answers regarding the map challenge that may be of interest to all of the participants.  We'll update this FAQ as needed.

Challenge Phase

1. Is the Cs listed in the target table (2.7) correct for the Apoferritin data?  No. There was an error in the script to generate the metadata requested for the challenge. The manufacturer specified Cs value for the Polara is 2.0 mm, but this has never been measured accurately for the instrument. In practice, this is an somewhat arbitrary fitting parameter that can be input during analysis of the raw data or refined during fitting. Followup question: What Cs do the defocus values provided in the particle stack refer to?  The provided defocus values assume Cs = 2.7. posted Nov 20, 2015, thanks to Niko Grigorieff for questions, and Chris Russo for answers

SDSC Gordon Info

Everyone who applied for SDSC Gordon compute time for the map challenge will receive an initial allocation of 22,000 service units per proposed target. Altogether 14 users plan to perform a total of 45 reconstructions. Some useful links:

Other things to be aware of:

SDSC Offers Supercomputer Resources; Map Challenge Submission Deadline Extended

Nov 9, 2015: We have two major announcements regarding the ongoing EMDataBank Map Challenge.

First, the San Diego Supercomputing Center (SDSC) is generously offering supercomputing resources to support the Map Challenge.  The resources, made available through an SDSC Director’s Discretionary Award, include 1 Million core-hours on SDSC Gordon and 20TB of sandbox data storage on Gordon’s parallel file system Data Oasis.

Announcing the 2nd EMDataBank Model Challenge

EMDataBank is pleased to announce the 2015/2016 Model Challenge.

All members of the Scientific Community--at all levels of experience--are invited to participate as Challengers, and/or as Assessors.

Benchmark targets of varying size and complexity have been selected from recently deposited 3DEM structures based on current state-of-the-art detectors and processing methods, in the resolution range 2.2-4.5 Å.


EMDataBank Validation Challenges are supported by NIH National Institute of General Medical Sciences

Please send your challenge questions, comments and feedback to

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