the final mle estimates are :

Variables

Coefficient

t-test

${\alpha }_0$

−20.53693

−13.31670***

$\ln {\text{GDP}}_{jt}$

2.20121

10.21116***

$\ln {\text{GDP}}_{it}$

0.15218

7.06446***

$\ln {\text{TRADE}}_{it}$

0.69870

5.35523***

$\ln {\text{DIST}}_{it}$

−0.17782

−1.55934

${\text{LANG}}_{it}$

0.98700

0.27270

${\beta }_0$

17.58383

8.13012***

${\text{GA}}_{it}$

0.86799

2.06281*

${\text{PR}}_{it}$

0.08107

6.12466***

${\text{FR}}_{it}$

−0.24202

−15.04025***

${\text{TB}}_{it}$

−4.01392

−2.37312**

${\text{BR}}_{it}$

6.70229

8.82357***

sigma-squared

13.05578

5.31245

gamma

0.73215

21.86390