i am new to gromacs(i know nothing about simulations) and i hav the following doubts.

1) When we set temperature in gromacs say 400 K to peroform a simulation. Does the system being simulated is initially at 400 K or gets heated up as the simulation is run??( from 300 k to 330 and 400 K for example)

2)When i performed a simulation for 5 ns at 490 K on a small 40 residue peptide i observed that one of the Beta strands was missing wat could be the possible reason??? is my simulation correct?? pls help

thanks in advance