In Section 3, we analyze the case ofindirect government control, i.e., state subsidization of privately owned media. We endoge-nize government control in Section 4, asking when the government would choose to take overprivately owned media. Section 5 extends the model to multiple media outlets.
Small Angle Gradient Echo Methods. The gradient echo technique is generally used in combination with an RF excitation pulse that has a small flip angle of less than 90Ë. We will discover that the advantage of this is that it permits the use of shorter TR values and this, in turn, produces faster image acquisition.
Gradient descent. Gradient descent is a first-order iterative optimization algorithm for finding the minimum of a function. To find a local minimum of a function using gradient descent, one takes steps proportional to the negative of the gradient (or of the approximate gradient) of the function at the current point. If instead one takes steps proportional to the positive of the gradient, one approaches a local maximum of that function; the procedure is then known as gradient ascent.