diff --git a/vignettes/articles/model-description.Rmd b/vignettes/articles/model-description.Rmd
index 6d3f882ee77fbbc0cea1249813df959c7a45d512..57a64f947c342efc31a7db64abf742064018fd56 100644
--- a/vignettes/articles/model-description.Rmd
+++ b/vignettes/articles/model-description.Rmd
@@ -211,7 +211,7 @@ net_Ur <- sum(p$Ur_a_ss)
 | \(\gamma \cdot T_n\) | Normoblast population (bone marrow)   | \(`r net_n`\)   |
 | \(\rss(a)\)  | Reticulocyte population (bone marrow) | \(`r net_r`\)   |
 | \(\Rss(a)\)  | Reticulocyte population (circulation) | \(`r net_R`\)   |
-| \(\Nss(a)\)  | Normoblast population (circulation)   | \(`r net_N`\)   |
+| \(\Nss(a)\)  | Normocyte population (circulation)    | \(`r net_N`\)   |
 | \(\Urss(a)\) | RBC population (spleen)               | \(`r net_Ur`\)  |
 | \(M_0\)      | Initial macrophage population         | \(`r p$M_t_1`\) |
 | \(I_0\)      | Initial infected RBC population       | \(`r p$I_t_1`\) |
@@ -271,7 +271,7 @@ df_u0 <- data.frame(
   where = rep(c("Circulation", "Spleen"),
               each = p$T_urbc)
 )
-df_u0$category <- ifelse(df_u0$age <= (3.5 * 24), "Young", "Old")
+df_u0$category <- ifelse(df_u0$age <= p$T_R, "Young", "Old")
 df_u0$category <- factor(df_u0$category, levels = c("Young", "Old"),
                          ordered = TRUE)
 ggplot(df_u0[df_u0$value > 0, ],