There are two models of protein folding that are currently being confirmed: 1  The diffusion collision model, in which a nucleus is formed, then the secondary structure is formed, and finally these secondary structures are collided together and pack tightly together.
ATT Validity Dates. 1  Each ATT is valid for a period of time specified by the BON/RB (the average length of an ATT is 90 days). 2  Once the BON/RB has declared you eligible to test and you receive your ATT, you must test within the validity dates on the ATT.
There are three pass/fail rules for the NCLEX examinations: the Run-Out-Of-Time rule, the Maximum-Length Exam Rule and the 95-Percent Confidence Interval Rule. The first reason that the exam could end is if the five-hour time limit has run out.