[pstricks] pstricks problem after upgrading to MacTex 2021

[Norberto Moreno Quiben]

Dear friends member:

After upgrading to MacTex 2021 and running the attached example I get 
the following message:

%%%% WARNING: Transparency operations ignored - need to use 
-dALLOWPSTRANSPARENCY

Error: /undefined in .setstrokeconstantalpha
Operand stack:
    -39.9045   -27.7565   0.0   -13.5066   1.0
Execution stack:
    %interp_exit   .runexec2   --nostringval--   --nostringval--   
--nostringval--   2   %stopped_push   --nostringval--   --nostringval--  
  --nostringval--   false   1   %stopped_push   1974   1   3   
%oparray_pop   1973   1   3   %oparray_pop   1961   1   3   %oparray_pop 
   1817   1   3   %oparray_pop   --nostringval--   %errorexec_pop   
.runexec2   --nostringval--   --nostringval--   --nostringval--   2   
%stopped_push   --nostringval--
Dictionary stack:
    --dict:729/1123(ro)(G)--   --dict:0/20(G)--   --dict:147/200(L)--   
--dict:182/300(L)--   --dict:38/200(L)--   --dict:131/200(L)--
Current allocation mode is local
Current file position is 148497
GPL Ghostscript 9.53.3: Unrecoverable error, exit code 1
### FAILED to generate 
/tmp/altpdflatex.2561-1617639517/carefully-examined-bad.pdf ()

And the expected pdf is not obtain. I know there must be a problem with 
ghostscript, but I am not able to identify.

Thanks in advance

Attached example:

\documentclass[10pt]{article}
\usepackage[utf8]{inputenc} %useful to type directly diacritic 
characters
\usepackage[T1]{fontenc}
\usepackage{textcomp}
\usepackage{pstricks,pst-jtree,pst-node}
%\usepackage[usenames]{color} %for the color
\usepackage{amssymb} %maths
\usepackage{amsmath} %maths
\usepackage[normalem]{ulem}
\usepackage{graphicx}
\usepackage{expex}
\begin{document}
*
\jtree[xunit=2.8em,yunit=1em]
\def\\{[labelgapb=-1.2ex]}%\@1
\def\Vi{V$\mskip-5mu _i$}
\! = {ST}
:[scaleby=1.5]{SN$\mskip-5mu _k$}(<vartri>{The student}) 
[scaleby=1.5]{T'}
:!b [scaleby=1.5]{SV}
:{h$\mskip-5mu _k$}{V'}
:{SAdv}(<vartri>{carefully})   [scaleby=1.5]{V'}
: {$h_i$}@A2  [scaleby=1.5]{SN}
  : {D}({the}) {N'}(<vert>{N}({test})) .
\psset{scaleby=.6 .6}
\!b = {T}
:!c {Conc}\\({$\scriptstyle [3sg]$}) .
\!c = {T}
:{\Vi}({examined}@B2 )  {T}\\({$\scriptstyle [pas]$})  .
\nccurve[angleB=-90,nodesepB=.5ex, 
nodesepA=.5ex,angleA=-90,ncurv=1]{<-}{B2}{A2}
\endjtree
\end{document}

<><><><><><><><><><><><><><><><><><><><><><><><><><>
Norberto Moreno Quibén
TELING (grupo de lingüística teórica de la UAH)
Coordinador de primer curso del grado de Humanidades
Dpto. Filología, Comunicación y Documentación
Área de Lengua Española
Universidad de Alcalá
C/ Trinidad, 5
28801, Alcalá de Henares (Madrid)
http://www.quiben.net
ORCID ID: https://orcid.org/0000-0002-7524-7636
"Much is uncertain, and must remain so." Mental Reality, Galen Strawson
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