Professor Stevens obtained tenure and promotion to full-professor status many years ago. Yet he continues to publish research papers in scholarly journals to satisfy his own curiosity and to maintain his professional prestige and status within the academic community. Publications are also necessary in order for Professor Stevens to receive pay raises at his university. Dr. Stevens publishing activities generate around $10,000 in royalty and other income separate from his university salary. This year, Dr. Stevens spent $750 of his own funds to travel to southern Utah to collect some critical pieces of data for his published work. What is the tax treatment of this expenditure?