Hypertrophic Pyloric Stenosis (HPS) — classic presentation:

• Age: 2–8 weeks (peak at 3–6 weeks)
• Gender: Males > females (4:1 ratio)
• Projectile, non-bilious vomiting (post-pyloric, so no bile)
• Hungry after vomiting (not ill-appearing)
• Olive-shaped mass palpable in right epigastrium (hypertrophied pylorus)
• Visible peristaltic waves (left to right)

Electrolyte imbalance:

Repeated vomiting of gastric acid (HCl) causes loss of H⁺ and Cl⁻:

\[\text{Loss of HCl} \Rightarrow \downarrow \text{Cl}^- \Rightarrow \uparrow \text{HCO}_3^- \Rightarrow \text{Metabolic Alkalosis}\]

Kidney compensates by retaining H⁺ and excreting K⁺ → Hypokalemia

Result: Hypochloremic, hypokalemic metabolic alkalosis

Diagnosis: Ultrasound (pyloric muscle thickness \(\geq 4\,\text{mm}\), channel length \(\geq 16\,\text{mm}\))

Treatment: First correct electrolytes and dehydration, then Ramstedt pyloromyotomy (surgical — curative).

Let $T \propto G^x h^y c^z$. Using dimensional formulas:

• $[T] = [T^1]$
• $[G] = [M^{-1} L^3 T^{-2}]$
• $[h] = [M L^2 T^{-1}]$
• $[c] = [L T^{-1}]$

Comparing powers of $M, L, T$:

1. $-x + y = 0 \implies x = y$
2. $3x + 2y + z = 0 \implies 5x + z = 0 \implies z = -5x$
3. $-2x - y - z = 1 \implies -3x - (-5x) = 1 \implies 2x = 1 \implies x = 1/2$

Thus, $x=1/2, y=1/2, z=-5/2$. The expression is $\sqrt{\frac{Gh}{c^5}}$.

Gestational Diabetes Mellitus (GDM) — Diagnosis by OGTT (WHO 2013 / IADPSG criteria):

Initial Management (NICE/ADA guidelines):

1. Medical Nutrition Therapy (MNT): Carbohydrate control (40–45% of calories), low GI foods, 3 meals + 2–3 snacks/day
2. Physical activity: 30 min moderate exercise daily (e.g., walking)
3. Self-monitoring blood glucose (SMBG) 4× daily
4. Reassess in 1–2 weeks

Target glucose levels:

• Fasting: \(\leq 5.3\,\text{mmol/L}\)
• 1-hour post-meal: \(\leq 7.8\,\text{mmol/L}\)
• 2-hour post-meal: \(\leq 6.7\,\text{mmol/L}\)

If targets not met with MNT after 2 weeks → Add insulin (preferred) or metformin. Insulin does not cross placenta; metformin does but is used in many guidelines.

Polarization is one of the key ways in which language fails as a communication tool. The textbook explains that languages typically offer binary or extreme descriptors — good or bad, yes or no, right or wrong — when reality is usually a complex continuum. Examples:

• A person is called “good” or “bad” — but in reality most people have both qualities
• At elections, you vote yes or no to a candidate's entire platform — but you may agree with some policies and disagree with others
• You call a film “good” or “bad” — but you might love the music and hate the direction

Polarized language forces communicators to take extreme positions that do not reflect their actual nuanced views. This distorts communication, causes people to make and then over-defend oversimplified judgments, and is a significant barrier to productive dialogue — especially in political and social discourse in mass media.