Walter Sizer, mathematics, attended the Progress on Difference Equations Conference in Honor of Prof. Jerry Ladas, held in Bedlewo, Poland, May 25-29. He presented the paper, “Further Instances of Periodicity in May’s Host Parasitoid Equation.” Also this summer his earlier paper, “Periodicity in May’s Host Parasitoid Equation”, was published in the book Advances in Discrete Dynamical Systems edited by S. Elaydi et al. and published by the Mathematical Society of Japan.