John C. “Curlee” Robertson and Maureen Kearns received our annual award for excellent teaching by graduate students.

# Marriott’s doctoral defense

John Marriott, a student of Prof. Monique Chyba, will defend his doctoral dissertation on September 5.

#### Abstract

This work addresses the contrast problem in nuclear magnetic resonance as a Mayer problem in
optimal control. This is a problem motivated by improving the visible contrast in magnetic resonance
imaging, in which the magnetization of the nuclei of the substances imaged are first prepared by
being set to a particular con figuration by an external magnetic field, the control. In particular we
examine the contrast problem by saturation, wherein the magnetization of the first substance is
set to zero. This system is modeled by a pair of Bloch equations representing the evolution of the
magnetization vectors of the nuclei of two di fferent substances, both influenced by the same control
field.
More…

# The zeros of entire functions

Graduate student Rintaro “Yoshi” Yoshida will defend the degree of Ph.D. on Thursday May 2, 2:00pm, in Keller 301.

We invite the reader to consider the entire function
$$\varphi_{_{1/5}}(x) = \sum_{k=0}^\infty \frac{x^k}{(k!)^{(6/5)}}.$$
Do you think this function has any non-real zeros? Does it belong to the Laguerre-Pólya class? See the draft dissertation for answers.