Mathematical Approaches to Stable Investing

Zachariah Sinkala Publishing
Zachariah Sinkala Publishing  ·  Mathematics for Investors, Health & Living Systems

Structure before
speculation.

Books, workbooks, and analytical tools applying mathematical systems thinking to cardiovascular physiology, portfolio stability, investor behavior, and health biomarker tracking.

19
Physiology chapters
18+
Biomarkers tracked
58%
NIH diabetes risk reduction
0–100
Portfolio diagnostic range
Book · In Development

Volume 2: Respiratory
& Renal Physiology

The Mathematics of the Living Body

Ventilation-perfusion matching, renal tubular transport, acid-base regulation, and the feedback architecture shared between lung and kidney.

In Development
Coming 2026
Live Now Digital  ·  PDF Workbook

Stoic Investing:
Stability Reflection Workbook

Companion to the annotated Meditations

18 modules in investor discipline, behavioral analysis, and the Stability Score framework. Behavioral reflection structured around a quantitative diagnostic. Not a journal — a system.

90 pages 1,274 fillable fields AcroForm PDF Immediate download
$19
Digital fillable edition
Get the workbook  →
82 STABLE
Sample Stability Score
Live Now Book  ·  Paperback + Kindle

Stoic Investing:
Stability Under Market Stress

An annotated edition of Marcus Aurelius’s Meditations

18 parts covering drawdown discipline, noise and narrative, time horizon, and the Stability Score framework. Public domain text, original commentary.

Annotated Meditations 18 parts Kindle + Paperback
Available on Amazon
Paperback · Kindle
View on Amazon  →
Live Now Book  ·  Paperback + Ebook

The Algorithm
of Life

BioFlywheel Series

A mathematical systems framework that applies the governing algorithms of biological life — homeostasis, feedback control, and adaptive stability — to the design of a resilient financial and personal life. Structure over speculation, at every scale.

264 pages Paperback + Ebook BioFlywheel framework IngramSpark · D2D
$9.99 ebook
Paperback · Ebook · Available now
Get the book  →
Tool · Web App

Stability Score
Calculator

Quantitative portfolio diagnostic

Input four portfolio parameters. Receive a Stability Score from 0 to 100 with structural diagnosis and indicated actions. Designed for quarterly recalibration.

Four inputs 0–100 diagnostic Quarterly calibration
Coming Soon
In development
Live Now PDF + Excel  ·  Digital Bundle

Math-Optimized Life Dashboard

A quantitative health ledger for the long game

Track 18+ biomarkers — blood pressure, A1C, cholesterol, kidney, thyroid, and more — with a simple slope formula that tells you whether each metric is rising, falling, or stable. The same trend-slope logic used in computational biology, applied to your own labs.

10-page printable PDF Excel workbook 18+ biomarkers Auto-slope calculator Google Sheets compatible Conditional formatting
$17 / $37 bundle
PDF only · PDF + Excel bundle
Get the ledger  →
Annual Trend Analysis · Slope = (last − first) ÷ years
Fasting Glucose
+2.8/yr
HbA1c
+0.18/yr
LDL Cholesterol
+4.1/yr
Systolic BP
−1.2/yr
eGFR (Kidney)
+0.3/yr
Slope = (most recent − oldest) ÷ years · positive = rising · negative = falling
Live Now PDF + Excel  ·  Digital Bundle

DASH Diet
Math Planner

Quantitative compliance tracker for blood pressure control

NIH / NHLBI · DASH reduces systolic BP by 5.5 mmHg · #1 Heart-Healthy Diet 2025

Weekly compliance scorer with auto-slope. Tracks both sodium targets (2,300 mg & 1,500 mg) and both calorie plans (2,000 & 1,600 cal). Links diet compliance to blood pressure outcomes.

10-page PDF 6-sheet Excel Auto-compliance score BP correlation
$17
PDF + Excel · Instant download
Get the planner  →
Live Now PDF + Excel  ·  Digital Bundle

Diabetes Prevention
Tracker

NIH DPP lifestyle goal tracker with slope analysis

NIH / NIDDK · 58% diabetes risk reduction · 71% for adults 60+ · 22-year follow-up

Tracks the two NIH DPP goals — 7% weight loss and 150 min/week activity — with auto-computed slopes. Includes the 16-week NIH Lifestyle Balance program session tracker.

10-page PDF 6-sheet Excel 219 formulas 16-week program
$17
PDF + Excel · Instant download
Get the tracker  →
Live Now Book  ·  Paperback + Ebook

Connected
Health

Mathematical frameworks for personal health optimization

Applies the quantitative systems thinking behind the BioFlywheel methodology to personal health — connecting biomarker trends, lifestyle inputs, and long-term outcomes through mathematical frameworks grounded in clinical evidence.

Paperback + Ebook Systems framework Evidence-based
$9.99 print / $2.99 ebook
Paperback · Ebook · Available now
Get the book  →

One equation.
One living system.

A bi-weekly newsletter applying mathematical systems thinking to physiology, cancer biology, and quantitative finance. Each issue: one equation, the molecular biology behind it, one worked number with a range, and one product or read.

Free. Published every two weeks. No speculation.

Subscribe free  →
bioflywheel.beehiiv.com · by Zachariah Sinkala
The BioFlywheel Letter — Issue 1 · April 2026
The Equation
MAP = CO × TPR
Mean arterial pressure equals cardiac output times total peripheral resistance. Not a simplification — an exact identity that organises everything in cardiovascular medicine.
The Biology
CO is driven by the troponin complex gating calcium access to actin-myosin. TPR is driven by myosin light chain kinase phosphorylation, modulated by NO → cGMP and AngII → AT₁ → PKC. Two proteins. One equation.
The Number
Patient: MAP ≈ 71 mmHg (88/62, HR 118). At the lower limit. Compensated by elevated CO against falling TPR. Restoring MAP = fixing CO, TPR, or both.

A structural diagnostic,
not a market call.

The Stability Score answers one question: how stable is the structure of this portfolio? It does not predict returns — it measures whether your portfolio is designed to hold through stress, or amplify it.

Four inputs, each scored 0–25, summed to 100. Recalculate quarterly.

25
Concentration Risk
Top-3 position weight. Single-position override above 30%.
25
Drawdown Recovery
Years to recover from max drawdown at average return rate.
25
Volatility Coherence
Portfolio volatility vs. your real behavioral time horizon.
25
Liquidity Reserve
Capital convertible to cash within 72 hours.
75–100
Stable
Monitor. No structural adjustment required.
50–74
Watchlist
Plan adjustment. Not yet urgent.
25–49
Fragile
Structural review indicated now.
0–24
Critical
Action required regardless of market direction.
Compute your score in the workbook  →
About

Zachariah Sinkala Publishing is the applied mathematics imprint of Zachariah Sinkala — computational cancer biologist, mathematician, and author of The Mathematics of the Living Body series.

The BioFlywheel methodology originated in research on biological homeostasis and metastatic dormancy. It is now applied across three domains: cardiovascular physiology (the MLB book series), portfolio stability (the Stability Score and Stoic Investing line), and personal health biomarker analysis (the NIH-based health trackers). The slope methodology used in the health trackers is the same longitudinal trend analysis used in computational oncology.

All physiology content is grounded in peer-reviewed literature with landmark citations per chapter. All health products are grounded in NIH/NIDDK and NIH/NHLBI published clinical evidence. All finance products are grounded in quantitative risk frameworks. Nothing relies on hype, prediction, or speculation.

Anti-hype. Structure-first. Mathematical verification over speculation.