diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index d114f87b..e6c8423b 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -17,7 +17,7 @@ jobs:
       matrix:
         # don't run on macos-latest; it can't install pytables
         os: [ubuntu-latest, windows-latest]
-        python-version: ["3.10"]
+        python-version: ["3.12"]
 
     steps:
       - uses: actions/checkout@v2
diff --git a/ModSimPyNotebooks.zip b/ModSimPyNotebooks.zip
index 2d5f007d..6f62baed 100644
Binary files a/ModSimPyNotebooks.zip and b/ModSimPyNotebooks.zip differ
diff --git a/chapters/chap22.ipynb b/chapters/chap22.ipynb
index 0a5f28ee..fd0badd1 100644
--- a/chapters/chap22.ipynb
+++ b/chapters/chap22.ipynb
@@ -32,7 +32,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 8,
    "id": "electoral-turkey",
    "metadata": {
     "tags": []
@@ -53,7 +53,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 9,
    "id": "formal-context",
    "metadata": {
     "tags": []
@@ -77,7 +77,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 10,
    "id": "progressive-typing",
    "metadata": {
     "tags": []
@@ -155,7 +155,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 11,
    "id": "handy-terrain",
    "metadata": {},
    "outputs": [],
@@ -175,7 +175,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": 12,
    "id": "vocal-latino",
    "metadata": {},
    "outputs": [],
@@ -185,7 +185,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": 13,
    "id": "controversial-shower",
    "metadata": {},
    "outputs": [],
@@ -193,34 +193,6 @@
     "A.y"
    ]
   },
-  {
-   "cell_type": "markdown",
-   "id": "earlier-contemporary",
-   "metadata": {},
-   "source": [
-    "You can also access them by index using brackets, like this:"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 7,
-   "id": "digital-channels",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "A[0]"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 8,
-   "id": "automated-drove",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "A[1]"
-   ]
-  },
   {
    "cell_type": "markdown",
    "id": "grave-burst",
@@ -232,7 +204,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 14,
    "id": "conditional-latitude",
    "metadata": {},
    "outputs": [],
@@ -251,7 +223,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 10,
+   "execution_count": 15,
    "id": "encouraging-cabinet",
    "metadata": {},
    "outputs": [],
@@ -278,7 +250,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 11,
+   "execution_count": 16,
    "id": "peripheral-tattoo",
    "metadata": {},
    "outputs": [],
@@ -303,7 +275,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 12,
+   "execution_count": 17,
    "id": "strange-cleaning",
    "metadata": {},
    "outputs": [],
@@ -324,7 +296,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 13,
+   "execution_count": 18,
    "id": "cellular-community",
    "metadata": {},
    "outputs": [],
@@ -348,7 +320,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 14,
+   "execution_count": 19,
    "id": "monetary-firmware",
    "metadata": {},
    "outputs": [],
@@ -371,7 +343,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 15,
+   "execution_count": 20,
    "id": "explicit-piano",
    "metadata": {},
    "outputs": [],
@@ -389,7 +361,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 16,
+   "execution_count": 21,
    "id": "relative-republic",
    "metadata": {},
    "outputs": [],
@@ -421,7 +393,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 17,
+   "execution_count": 22,
    "id": "narrative-latest",
    "metadata": {
     "tags": []
@@ -459,7 +431,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 18,
+   "execution_count": 23,
    "id": "bored-billy",
    "metadata": {
     "tags": []
@@ -509,7 +481,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 19,
+   "execution_count": 24,
    "id": "ethical-donna",
    "metadata": {},
    "outputs": [],
@@ -527,7 +499,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 20,
+   "execution_count": 25,
    "id": "legitimate-gossip",
    "metadata": {},
    "outputs": [],
@@ -547,7 +519,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 21,
+   "execution_count": 26,
    "id": "legal-terminal",
    "metadata": {
     "tags": []
@@ -583,7 +555,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 22,
+   "execution_count": 27,
    "id": "frank-chick",
    "metadata": {},
    "outputs": [],
@@ -606,7 +578,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 23,
+   "execution_count": 28,
    "id": "suitable-salem",
    "metadata": {
     "tags": []
@@ -666,7 +638,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 24,
+   "execution_count": 29,
    "id": "closing-simon",
    "metadata": {},
    "outputs": [],
@@ -696,7 +668,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 25,
+   "execution_count": 30,
    "id": "brief-level",
    "metadata": {
     "tags": []
@@ -720,7 +692,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 26,
+   "execution_count": 31,
    "id": "threatened-alberta",
    "metadata": {},
    "outputs": [],
@@ -738,7 +710,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 27,
+   "execution_count": 32,
    "id": "special-background",
    "metadata": {},
    "outputs": [],
@@ -761,7 +733,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 28,
+   "execution_count": 33,
    "id": "prospective-external",
    "metadata": {},
    "outputs": [],
@@ -779,7 +751,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 29,
+   "execution_count": 34,
    "id": "medieval-calvin",
    "metadata": {},
    "outputs": [],
@@ -798,7 +770,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 30,
+   "execution_count": 35,
    "id": "gorgeous-survey",
    "metadata": {},
    "outputs": [],
@@ -817,7 +789,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 31,
+   "execution_count": 36,
    "id": "failing-bangkok",
    "metadata": {},
    "outputs": [],
@@ -836,7 +808,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 32,
+   "execution_count": 37,
    "id": "copyrighted-highway",
    "metadata": {},
    "outputs": [],
@@ -855,7 +827,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 33,
+   "execution_count": 38,
    "id": "structured-adams",
    "metadata": {},
    "outputs": [],
@@ -883,7 +855,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 34,
+   "execution_count": 39,
    "id": "spare-burst",
    "metadata": {},
    "outputs": [],
@@ -908,7 +880,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 35,
+   "execution_count": 40,
    "id": "dated-browse",
    "metadata": {},
    "outputs": [],
@@ -941,7 +913,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 36,
+   "execution_count": 41,
    "id": "resistant-vegetation",
    "metadata": {},
    "outputs": [],
@@ -964,7 +936,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 37,
+   "execution_count": 42,
    "id": "starting-fabric",
    "metadata": {},
    "outputs": [],
@@ -1011,7 +983,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 38,
+   "execution_count": 43,
    "id": "prescription-boutique",
    "metadata": {
     "tags": []
@@ -1060,7 +1032,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 39,
+   "execution_count": 44,
    "id": "optical-weather",
    "metadata": {},
    "outputs": [],
@@ -1072,7 +1044,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 40,
+   "execution_count": 45,
    "id": "acknowledged-belgium",
    "metadata": {},
    "outputs": [],
@@ -1082,7 +1054,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 41,
+   "execution_count": 46,
    "id": "spatial-ensemble",
    "metadata": {},
    "outputs": [],
@@ -1092,7 +1064,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 42,
+   "execution_count": 47,
    "id": "domestic-apparatus",
    "metadata": {},
    "outputs": [],
@@ -1102,7 +1074,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 43,
+   "execution_count": 48,
    "id": "correct-pittsburgh",
    "metadata": {},
    "outputs": [],
@@ -1122,7 +1094,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 44,
+   "execution_count": 49,
    "id": "global-referral",
    "metadata": {},
    "outputs": [],
@@ -1134,7 +1106,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 45,
+   "execution_count": 50,
    "id": "appointed-sugar",
    "metadata": {},
    "outputs": [],
@@ -1144,7 +1116,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 46,
+   "execution_count": 51,
    "id": "specialized-mediterranean",
    "metadata": {},
    "outputs": [],
@@ -1178,7 +1150,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 47,
+   "execution_count": 52,
    "id": "directed-moisture",
    "metadata": {
     "tags": []
@@ -1201,7 +1173,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 48,
+   "execution_count": 53,
    "id": "fuzzy-register",
    "metadata": {
     "tags": []
@@ -1225,7 +1197,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 49,
+   "execution_count": 54,
    "id": "returning-fellowship",
    "metadata": {
     "tags": []
@@ -1247,7 +1219,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 50,
+   "execution_count": 55,
    "id": "reasonable-swaziland",
    "metadata": {
     "tags": []
@@ -1270,7 +1242,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 51,
+   "execution_count": 56,
    "id": "attached-shower",
    "metadata": {
     "tags": []
@@ -1290,7 +1262,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 64,
+   "execution_count": 57,
    "id": "christian-camcorder",
    "metadata": {},
    "outputs": [],
@@ -1312,7 +1284,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 53,
+   "execution_count": 58,
    "id": "heated-belfast",
    "metadata": {
     "tags": []
@@ -1333,7 +1305,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 54,
+   "execution_count": 59,
    "id": "engaged-provision",
    "metadata": {},
    "outputs": [],
@@ -1343,7 +1315,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 55,
+   "execution_count": 60,
    "id": "directed-fiber",
    "metadata": {},
    "outputs": [],
@@ -1353,7 +1325,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 56,
+   "execution_count": 61,
    "id": "framed-dealer",
    "metadata": {},
    "outputs": [],
@@ -1363,7 +1335,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 57,
+   "execution_count": 62,
    "id": "accomplished-elizabeth",
    "metadata": {},
    "outputs": [],
@@ -1373,7 +1345,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 58,
+   "execution_count": 63,
    "id": "going-techno",
    "metadata": {},
    "outputs": [],
@@ -1383,7 +1355,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 59,
+   "execution_count": 64,
    "id": "brief-saying",
    "metadata": {},
    "outputs": [],
@@ -1393,7 +1365,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 60,
+   "execution_count": 65,
    "id": "spare-pregnancy",
    "metadata": {},
    "outputs": [],
@@ -1403,7 +1375,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 61,
+   "execution_count": 66,
    "id": "catholic-staff",
    "metadata": {},
    "outputs": [],
@@ -1413,7 +1385,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 62,
+   "execution_count": 67,
    "id": "broad-sequence",
    "metadata": {},
    "outputs": [],
@@ -1433,7 +1405,7 @@
  "metadata": {
   "celltoolbar": "Tags",
   "kernelspec": {
-   "display_name": "Python 3 (ipykernel)",
+   "display_name": "ModSimPy",
    "language": "python",
    "name": "python3"
   },
@@ -1447,7 +1419,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.10.13"
+   "version": "3.13.11"
   }
  },
  "nbformat": 4,
diff --git a/environment.yml b/environment.yml
index 56d42fc4..628e539e 100644
--- a/environment.yml
+++ b/environment.yml
@@ -2,7 +2,8 @@ name: ModSimPy
 channels:
   - conda-forge
 dependencies:
-  - python
+  # Core dependencies for users
+  - python=3.13
   - jupyter
   - numpy
   - matplotlib
@@ -16,6 +17,5 @@ dependencies:
   - pytables
   - pip
 
-# pip install pytest nbmake
-# pip install jupyter-book ghp-import
-# pip install pypandoc fastdoc
+# For development dependencies, use environment-dev.yml
+# Install with: mamba env create -f environment-dev.yml