## What is the basis for the rhythmicity observed in the SCN?

1.Why do you think animals, including humans, would evolve a system in which their testosterone levels would fluctuate with winning and losing in competitive situations?

2. How do shift work, jet lag, and daylight saving time affect our normal circadian rhythms?

3. What is the basis for the rhythmicity observed in the SCN?

4.What can we learn from the EEG recordings taken from different stages of waking and sleep?

5. In what ways should sleep be considered an active, as opposed to a passive, process?

### Design a rectangular pre-stressed beam section (on allowable stress basis) that supports a live load of 2.5 k/ft on a span of 30 ft. Pre-stress losses = 22%. fc 6000 psi, ftt = -208 psi, fct = 2880 psi, fcs = 3600 psi, fts = -465 psi.

1.A rectangular beam of 12 in. width and 18 in. depth is pre-stressed by a force of 20 kip applied through a tendon of wires of 2 in. diameter located….

### Determine the maximum unbraced length of beam to satisfy the requirement of adequate lateral support.

1. For the braced column section and the loading shown in Figure P10.20, determine the limit states for which the column should be designed. Use A992 steel 2. Design a….

### Design a beam of A992 steel for the loading shown in Figure P11.2.

1.Design a beam of A992 steel for the loading shown in Figure P11.2. The compression flange bracing is provided at each concentrated load. The selected section should be such that….