alone, five interdisciplinary research centers were created or substantially expanded; these include the Center for Health-care Financing, the Center for Global Women's Health at the Nursing School, the $13 million Morris Arboretum's Horticulture Center, the $15 million Jay H. Baker Retailing Center at Wharton and the $13 million Translational Research Center at Penn Medicine. With these additions, Penn now counts 165 research centers hosting a research community of over 4,300 faculty and over 1,100 postdoctoral fellows, 5,500 academic support staff and graduate student trainees. To further assist the advancement of interdisciplinary research President Amy Gutmann established the "Penn Integrates Knowledge" title awarded to selected Penn professors "whose research and teaching exemplify the integration of knowledge". These professors hold endowed professorships and joint appointments between Penn's schools. Penn is also among the most prolific producers of doctoral students. With 487 PhDs awarded in 2009, Penn ranks third in the Ivy League, only behind Columbia and Cornell (Harvard did not report data). It also has one of the highest numbers of post-doctoral appointees (933 in number for 2004–2007), ranking third in the Ivy League (behind Harvard and Yale) and tenth nationally. In most disciplines Penn professors' productivity is among the highest in the nation and first in the fields of epidemiology, business, communication studies, comparative literature, languages, information science, criminal justice and criminology, social sciences and sociology. According to the National Research Council nearly three-quarters of Penn's 41 assessed programs were placed in ranges including the top 10 rankings in their fields, with more than half of these in ranges including the top five rankings in these fields. Penn's research tradition has historically been complemented by innovations that shaped higher education. In addition to establishing the first medical school, the first university teaching hospital, the oldest continuously operating degree-granting program in chemical engineering, the first business school, and the first student union, Penn was also the cradle of other significant developments. In 1852, Penn Law was the first law school in the nation to publish a law journal still in existence (then called The American Law Register, now the Penn Law Review, one of the most cited law journals in the world). Under the deanship of William Draper Lewis, the law school was also one of the first schools to emphasize legal teaching by full-time professors instead of practitioners, a system that is still followed today. The Wharton School was home to