Li do not use 'baseline offset' whilst collecting data. The 'baseline offset' algorithm will work against your voltage adjustments as you make them - it is possible to be fooled into bringing your voltage down so afar as to make positive and negatives look exactly alike! If you want to use the 'baseline offset' to make your data look "pretty" then do so post acquisition. All the algorithm does is to take 'zero' off axis events and place them in the first decade as a "pretty" gaussian. 'Baseline offset' is recorded as a flag setting in the file header to tell the application whether to use the 'baseline offset' algorithm or not. 'Baseline offset' is still selectable post acquisiton and during any subsquent analysis. However if you use 'baseline offset' during acquisiton you may set your fluorescence gains incorrectly and collect incorrect data. You can toggle it on and off whilst setting up to see what your results can look like when it is on but I seriously recommend you leave it off for actual acquisition. It is a very dangerous toy, I have had several users destroy their data using this function incorrectly even after they were warned not too. I have a large warning sign on all our Beckman Coulter flow cytometers NOT to use the 'Baseline Offset' during acquisition. Beckman Coulter have provided a liitle information about 'baseline offset' in the CXP help file under Workspace Preferences - Plot Display - Baseline Offset. Its probably in a similar place with Expo32. Alan ############################################################################ E-mail:alan.bishop@imvs.sa.gov.au Tel: +61 8 82223602 Fax: +61 8 82323139 Mail: Alan Bishop, MA cantab. Senior Flow Cytometrist Detmold Flow Cytometry Facility PO Box 14 Rundle Mall IMVS ADELAIDE SA 5000 AUSTRALIA > -----Original Message----- > From: chen li [mailto:chen_li3@yahoo.com] > Sent: Wednesday, 20 June 2007 03:29 > To: Cytometry Mailing List > Subject: baseline offset in FC500 > > > Dear all, > > I just wonder what the purpose of baseline offset is > in FC500. What are the differences between using and > without using this feature when collect Flow data? > > Thanks, > > > Li > > > __________________________________________________________________ > __________________ > Building a website is a piece of cake. Yahoo! Small Business > gives you all the tools to > get online. > http://smallbusiness.yahoo.com/webhosting >Received on Thu Jun 21 13:18:00 2007
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