%% auteur : Abidi

15 setxunit
-8 8 setxrange
-5 7 setyrange

/arcangleU 10 def   %% angle au depart de la fleche
/arcangleV 10 def   %% oppose de l'angle a l'arrivee de la fleche
/nodesep 10 def      %% espace en picas separant les points A et B de
                    %% l'extremite de la connexion              

/dx_boxit 3 store
/dy_boxit 3 store
/U {0 2.5} def
/V {0 -2.5} def
/INI {-3 0} def
/ACT {3 0} def
/AUT {0 5} def

%setTimes
%circleit            %% encerclement du prochain label
(U) ovalnode           %% declaration d'un node circulaire (A)
<latex>
\begin{tabular}{c}
$u$\\activateur
\end{tabular}
</latex>
U cctexlabel

(U) /ul nodepoint (U1) enode 
(U) /ur nodepoint (U2) enode

(U) /dl nodepoint (U3) enode 
(U) /dr nodepoint (U4) enode

%circleit            %% encerclement du prochain label
(V) ovalnode           %% declaration d'un node circulaire (B)
<latex>
\begin{tabular}{c}
$v$\\inhibiteur
\end{tabular}
</latex>
V cctexlabel


(V) /ul nodepoint (V3) enode 
(V) /ur nodepoint (V4) enode

/angleA 90 def
/angleB 90 def
(U1) (U2) (->) nccurve
/angleA 135 def
/angleB -135 def
(V3) (U3) (->) nccurve
/angleA -45 def
/angleB 45 def
(U4) (V4) (->) nccurve

<latex>
autocatalyse
</latex>
AUT uctexlabel

<latex>
inhibition
</latex>
INI {90} cctexlabel

<latex>
activation
</latex>
ACT {-90} cctexlabel

/U10 {(U) /cr nodepoint 2 0 addc} def
/U11 {U10 1 0 addc} def
/U12 {U10 2 0 addc} def
/U13 {U10 3 0 addc} def
/angleA -45 def
/angleB 135 def
/nodesep 0 def
U10 U11 (-) pccurve
U11 U12 (-) pccurve
/angleA -45 def
/angleB 180 def
U12 U13 (->) pccurve
<latex>
diffusion
</latex>
U11 U12 addc 0.5 0 mulc uctexlabel

/V10 {(V) /cr nodepoint 2 0 addc} def
/V11 {V10 1 0 addc} def
/V12 {V10 2 0 addc} def
/V13 {V10 3 0 addc} def
/V14 {V10 4 0 addc} def
/angleA -45 def
/angleB 135 def
/nodesep 0 def
V10 V11 (-) pccurve
V11 V12 (-) pccurve
V12 V13 (-) pccurve
/angleA -45 def
/angleB 180 def
V13 V14 (->) pccurve
<latex>
diffusion
</latex>
V12 uctexlabel


/U5 {(U) /cl nodepoint -4 1 addc} def
<latex>
$\gamma a$
</latex>
U5 cltexlabel
/nodesep 5 def
/angleA 30 def
/angleB 150 def
U5 (U) /cl nodepoint -1.5 0 addc (->) pccurve

/U6 {(U) /cl nodepoint -4 -1 addc} def
<latex>
$\gamma u$
</latex>
U6 cltexlabel
/nodesep 5 def
/angleA -150 def
/angleB -30 def
(U) /cl nodepoint -1.5 0 addc U6 (->) pccurve


/V5 {(V) /cl nodepoint -4 1 addc} def
<latex>
$\gamma b$
</latex>
V5 cltexlabel
/nodesep 5 def
/angleA 30 def
/angleB 150 def
V5 (V) /cl nodepoint -1.5 0 addc (->) pccurve

/V6 {(V) /cl nodepoint -4 -1 addc} def
<latex>
$\gamma\alpha v$
</latex>
V6 cltexlabel
/nodesep 5 def
/angleA -150 def
/angleB -30 def
(V) /cl nodepoint -1.5 0 addc V6 (->) pccurve