[Pruritus in chronic kidney insufficiency]. / Prurito en la insuficiencia renal crónica.

Itching is the dermatologic symptom more often found in patients with chronic renal failure. We have studied 80 patients with end-stage renal disease; itching was present in 56.3% of the cases. We didn't detected in this study any correlation between itching, long term hemodialysis, high calcium, phosphorus, alkaline phosphatase or phosphocalcic product levels. We have seen: 1. Those patients with itching were older than the rest. 2. Itching was important in those patients with residual diuresis less than 500 ml/day (p greater than 0.01). 3. Those men without itching had higher hematocrit levels (p greater than 0.01). 4. Histologic findings on optic and electronic microscopy were more frequent in patients who presented this symptom.

Designing musical structures using a constrained optimization approach.

The paper discusses the application of numerical optimizing techniques to musical structures. It is shown that the natural tendency to emulate the instrument maker by optimizing the characteristic frequencies of the structure is not always the most appropriate strategy, and that in cases where one or more possible solutions exist it is more appropriate to specify the frequency requirements as a constraint. The strategy is illustrated using a xylophone bar.