int n_N;
int n_X;
int n_group;
int GROUP_N[3, n_group];
array[3, n_group] int GROUP_X;

// DATA
vector[n_X] time_X;
vector[n_X] conc;

real time_N[n_N];
int Nsurv[n_N] ;
int Nprec[n_N] ;

// PRIORS
real kd_meanlog10;
real kd_sdlog10;
real hb_meanlog10;
real hb_sdlog10;

int HB_FIXED;
real hb_value;

// Parameters for integration of differentiol equations
// real rel_tol;
// real abs_tol;
// int max_num_steps;
