[phenixbb] question on merging multiple data

[fn1 at rice.edu]

Hi all,

Sorry to post here. I tried to post to CCP4BB, but it takes me one day  
to subscribe, confirm and doing again and again, but i still could not  
email to the list. Hope someone could help me. Thanks!

I have to merge several datasets from different crystals because the  
crystals suffer from severe radiation damage.

I read some previous posts and follow the protocol as described,
1) individually process the data;
2) scaleit to compare the Rfactors between different datasets;
3) renumber the batch number;
4) for those with low R-factor files (below 0.25), sort them;
5) scala the sorted file.

the script i used for the SCALA is,
scales batch brotaion spacing 5

which is the one in CCP4 example script that recommended for  
synchrontron data.

For the first four dataset that are all cutoff to about 3.0A based on  
I/sigI, and the statistics are like this,


    N 1/d^2 Dmin(A) Rmrg  Rfull   Rcum  Av_I   SIGMA I/sigma
  $$
   1 0.0111  9.49  0.038  0.030  0.038   1934   125.2  15.5
   2 0.0222  6.71  0.050  0.009  0.044   1182    92.4  12.8
   3 0.0333  5.48  0.086  0.018  0.055    565    71.0   8.0
   4 0.0444  4.74  0.093  0.166  0.065    724   100.2   7.2
   5 0.0556  4.24  0.105  0.139  0.074    746   116.9   6.4
   6 0.0667  3.87  0.143  0.058  0.085    522   105.4   5.0
   7 0.0778  3.59  0.217  0.142  0.098    358   107.8   3.3
   8 0.0889  3.35  0.365  0.265  0.115    216   109.5   2.0
   9 0.1000  3.16  0.634  2.509  0.134    126   110.0   1.1
  10 0.1111  3.00  0.965 10.157  0.154     81   109.8   0.7



For the fifth data cutoff to 2.76A, the stastics for the single data  
is like this,


    N 1/d^2 Dmin(A) Rmrg  Rfull   Rcum  Av_I   SIGMA I/sigma
  $$
   1 0.0131  8.73  0.031  0.036  0.031   6866   416.2  16.5
   2 0.0263  6.17  0.034  0.036  0.032   2994   185.5  16.1
   3 0.0394  5.04  0.039  0.040  0.034   2327   185.5  12.5
   4 0.0525  4.36  0.039  0.045  0.036   3358   249.6  13.5
   5 0.0656  3.90  0.047  0.048  0.038   2226   184.2  12.1
   6 0.0788  3.56  0.064  0.059  0.041   1390   151.7   9.2
   7 0.0919  3.30  0.101  0.084  0.045    787   118.0   6.7
   8 0.1050  3.09  0.145  0.114  0.048    482    98.8   4.9
   9 0.1181  2.91  0.271  0.234  0.053    259    96.5   2.7
  10 0.1313  2.76  0.398  0.333  0.058    183   102.8   1.8


Then i merge this fifth data with the other four and get the stastics  
like this,


    N 1/d^2 Dmin(A) Rmrg  Rfull   Rcum   Av_I   SIGMA I/sigma
  $$
   1 0.0131  8.73  0.072  0.048  0.072    7545   954.4   7.9
   2 0.0263  6.17  0.100  0.057  0.085    3417   528.8   6.5
   3 0.0394  5.04  0.145  0.072  0.103    2497   543.6   4.6
   4 0.0525  4.36  0.158  0.089  0.121    3308   790.6   4.2
   5 0.0656  3.90  0.200  0.091  0.138    2374   710.3   3.3
   6 0.0788  3.56  0.299  0.128  0.158    1496   663.8   2.3
   7 0.0919  3.30  0.462  0.173  0.177     848   644.7   1.3
   8 0.1050  3.09  0.577  0.144  0.187     483   414.7   1.2
   9 0.1181  2.91  0.720  0.265  0.192     311   358.2   0.9
  10 0.1312  2.76  0.392  0.342  0.192     217   122.7   1.8


My question is that after why the SIG_I becomes very large at  
different resolution shells merging the five data. Say, at 8.73A,  
merging the four low-resolution files give about SIG_I of 125; the  
single high-resolution file give 416, but after merging, they give up  
to 954, is this normal? or i made something wrong?

Thank you very much in advance!
Fengyun