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).

The standard relation between these moduli is $\frac{9}{Y} = \frac{3}{\eta} + \frac{1}{K}$.

• Rearranging for $K$: $\frac{1}{K} = \frac{9}{Y} - \frac{3}{\eta} = \frac{9\eta - 3Y}{Y\eta}$
• $K = \frac{Y\eta}{9\eta - 3Y}$.

The correct behaviour of $g$:

• Inside the Earth ($d < R$): $g = \frac{GM}{R^3}d$ — linear increase from $g=0$ at centre to $g_{surface}$ at $d=R$.
• Outside the Earth ($d > R$): $g = \frac{GM}{d^2}$ — decreases as $1/d^2$.

The graph shows a straight line from origin to $(R, g_{max})$, then a smooth $1/d^2$ curve decreasing afterward. This is a linear rise inside and inverse-square fall outside, meeting at a sharp peak at $d = R$.

According to widely cited educational research on learning modalities, approximately 75% of knowledge is gained through the sense of sight (observation/visual learning). This underscores the importance of visual aids, demonstrations, and observational learning in the classroom.

Correct Answer: A — 75%.

The Schramm-Osgood Interactive Model (1954) was a major improvement over Shannon-Weaver: it added the field of experience, made encoding/decoding simultaneous and reciprocal, incorporated feedback, and acknowledged that meaning is interpreted, not merely decoded. However, the textbook explicitly identifies its key limitation: “Schramm's model, though less linear, still accounts for only bilateral communication between two parties. The complex, multiple levels of communication between several sources is beyond this model.” In mass communication, one source (a broadcaster) communicates simultaneously with millions of receivers with varying fields of experience, and feedback is delayed and indirect (ratings, letters, viewer surveys). The dyadic (two-party) assumption of the Schramm-Osgood model does not capture this complexity adequately, which is why later mass communication models were needed.