During which month should high-risk patients be vaccinated for influenza?

Which of the following conditions are associated with central apnea? 1. Congestive heart failure 2. Primary central nervous system lesions 3. High-altitude hypoxemia 4. Obesity

a. 1 and 4 only b. 2 and 3 only c. 1, 2, and 3 only d. 1, 2, 3, and 4

To determine the vertical angulation when using the bisecting technique, the central rays of the x-ray beam should be directed:

a. perpendicular to the image receptor. b. parallel to the image receptor. c. perpendicular to the imaginary bisector. d. parallel to the imaginary bisector.