[□ | □] □
[□=□ | □] □
[!□ | □] □
This combinatorial explosion allows the immune system to make potentially 1015 different kinds of receptors , although the actual number of distinct receptors present in the body at any given time is far less than this . Student at any elementary grade level possesses a firearm , the student shall be suspended for five days and shall be recommended for expulsion , regardless of whether there was a threat to use , attempt to use , or actual use of the firearm . As noted in Section IB , expressions of interest in transfer may be submitted at any time during the transfer process . Probably because it is too difficult to evolve receptor structures that are precisely complementary to epitopes that have never been encountered before . This policy does not cover individuals who are independent contractors paid through accounts payable . Models of the convergence of opinion in social systems have been the subject of a considerable amount of recent attention in the physics literature . PerfAnal : A Performance Analysis Tool This is a ( very , very ) basic profiling / performance analysis tool layered on top of hprof . Letters of application may be submitted at any time and shall be kept on file for at least two years from the date of submission .