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Experimental tracts heterogeneity
Posted: Sat Jul 12, 2008 7:42 am
In phase 2, the appearance of experimental tracts has become rather heterogeneous: it now spans from the typical large or minute rosette pattern to single dots, sometimes associated, at deep focus, with what looks like a bubble or dwelling at the tip of fan like heterogeneity in the gel. On occasion, tracts are literally framed in a square-like area. Does only the new magnification account for that ? And how do these experimental patterns relate to "real" tracts ?
All the best
Posted: Sun Jul 20, 2008 12:08 pm
bernard wrote:In phase 2, the appearance of experimental tracts has become rather heterogeneous: it now spans from the typical large or minute rosette pattern to single dots, sometimes associated, at deep focus, with what looks like a bubble or dwelling at the tip of fan like heterogeneity in the gel. On occasion, tracts are literally framed in a square-like area. Does only the new magnification account for that ? And how do these experimental patterns relate to "real" tracts ?
All the best
I've been waiting for Bryan Mendez or one of the Mods to answer your query, but since none have so far been forthcoming, this is how I see it:
All CM tracks have been derived from a small number of pre-phase 1 experimental tracks and potential phase 1 candidates. The team said long ago that they have been artificially placed by computer program into otherwise negative movies, randomly rotated and re-sized to make them appear different, and have deliberately been made more subtle for phase 2. The square-like frame you mention is evidence of unsophisticated pasting via Photoshop, or whatever program it is they use. There are many previous postings about these issues to be found via the forum Search facility.
Presumably, until the project finishes and putative tracks analysed, no one (including the team) can be absolutely sure what "real" ones might actually look like, that being the point and fascination of this project - it's a first!
Posted: Mon Jul 21, 2008 6:32 pm
John is absolutely correct. The calibration tracks are based on only a few of the pre-project test particle firings and phase 1 candidates. They are randomly resized and rotated to create a few thousand possible calibration movies. I believe MatLab is the program used to insert them into empty frames. We know they are empty, because they are from the flight spare collector, that never flew in space, but only sat in storage at Johnson Space center to be used as a comparison to the collector flown in space.
The occasional square pattern is a result of poor insertion into the empty frames. We've tried to eliminate the bad ones as we have been made aware of them in the FAQ thread: http://stardustathome.ssl.berkeley.edu/ ... php?t=1094
The one thing to be aware of is that the calibration frames are not meant to teach you what to look for, so much as to measure how sensitive you are to features that are of interest to us. None of the candidates have turned out to look like any of the original calibration movies. If people had only looked for things that look like those, we would have never found some of the very promising candidates that we are now investigating.
Posted: Mon Aug 11, 2008 6:37 pm
So many questions, sometimes it's frustrating spending so much time on this project but not getting to see what's really going on.
First of all I don't understand how a candidate can be very promising if it doesn't look like the original calibration movies. What else is there to base a candidate's promisity on? (yes it's a word) If you're basing it on how many votes it gets from dusters solely and not if it looks like a track, that's a problem. Dusters are suppose to judge candidates on how much it looks like a track. That is to say, does it look like a hole that extends from the surface down into the gel? Which is what the calibration movies look like, (the well made ones anyway, which most are) and really is the only way a hole can look. When lots of dusters vote on movies like one of the extracted
http://stardustathome.ssl.berkeley.edu/ ... =4589365V1
it is because they confuse holes with stuff on the surface that looks like a hole. That does not make it a promising candidate just because many people vote for it.
Ok I guess some of that was mildly sarcastic. I know that by "very promising" you meant "the most promising thing next to something that looks like a calibration movie", which we don't have. So I know you're doing the best with what you've got.
Next more serious question. After reviewing the first six extractions do you know more about their source as far as how they got in the gel? For example is there evidence of high speed impacts or were they there from the gel manufactoring or did they kind of slowly work themselves in? I think this info, while trivia to you, would be exciting for dusters to know since all we do is look for impact tracks and not the particle. I don't care what caused it, if someone sneezed on the gel and I found the track I'll name it. Plus it'd be nice to have more concrete feedback on "promising candidates" that turned out not to be IS so dusters can avoid voting on those types of features in phase III.