Question: What is the enrollment of undergraduates at the university that employed the person who declared the American frontier "closed" in 1893?

full_context: Document 1: Harvard University: The Harvard Crimson competes in 42 intercollegiate sports in the NCAA Division I Ivy League. Harvard has an intense athletic rivalry with Yale University culminating in The Game, although the Harvard–Yale Regatta predates the football game. This rivalry, though, is put aside every two years when the Harvard and Yale Track and Field teams come together to compete against a combined Oxford University and Cambridge University team, a competition that is the oldest continuous international amateur competition in the world.
Document 2: Education: In time, some ideas from these experiments and paradigm challenges may be adopted as the norm in education, just as Friedrich Fröbel's approach to early childhood education in 19th-century Germany has been incorporated into contemporary kindergarten classrooms. Other influential writers and thinkers have included the Swiss humanitarian Johann Heinrich Pestalozzi; the American transcendentalists Amos Bronson Alcott, Ralph Waldo Emerson, and Henry David Thoreau; the founders of progressive education, John Dewey and Francis Parker; and educational pioneers such as Maria Montessori and Rudolf Steiner, and more recently John Caldwell Holt, Paul Goodman, Frederick Mayer, George Dennison and Ivan Illich.
Document 3: Great Plains: The 100th meridian roughly corresponds with the line that divides the Great Plains into an area that receive 20 inches (510 millimetres) or more of rainfall per year and an area that receives less than 20 in (510 mm). In this context, the High Plains, as well as Southern Alberta, south-western Saskatchewan and Eastern Montana are mainly semi hot steppe land and are generally characterised by rangeland or marginal farmland. The region (especially the High Plains) is periodically subjected to extended periods of drought; high winds in the region may then generate devastating dust storms. The eastern Great Plains near the eastern boundary falls in the humid subtropical climate zone in the southern areas, and the northern and central areas fall in the humid continental climate.
Document 4: The Significance of the Frontier in American History: ``The Significance of the Frontier in American History ''is a seminal essay by the American historian Frederick Jackson Turner which advanced the Frontier Thesis of American history. It was presented to a special meeting of the American Historical Association at the World's Columbian Exposition in Chicago, Illinois in 1893, and published later that year first in Proceedings of the State Historical Society of Wisconsin, then in the Annual Report of the American Historical Association. It has been subsequently reprinted and anthologized many times, and was incorporated into Turner's 1921 book, The Frontier in American History, as Chapter I.
Document 5: Harvard University: Undergraduate admission to Harvard is characterized by the Carnegie Foundation as "more selective, lower transfer-in". Harvard College accepted 5.3% of applicants for the class of 2019, a record low and the second lowest acceptance rate among all national universities. Harvard College ended its early admissions program in 2007 as the program was believed to disadvantage low-income and under-represented minority applicants applying to selective universities, yet for the class of 2016 an Early Action program was reintroduced.
Document 6: Carl Kaestle: Carl Frederick Kaestle (born March 27, 1940) is University Professor and Professor of Education, History, and Public Policy emeritus at Brown University. His historical research has focused on the development of American schools, particularly in the 1800s. He has worked at the University of Chicago and University of Wisconsin–Madison and is a former president of the National Academy of Education.
Document 7: Chalisa famine: Together the two famines may have depopulated many regions of India, including, for example, 17 per cent of the villages in the Sirkali region of present-day Tamil Nadu, 60 per cent of the villages in the middle Doab of present-day Uttar Pradesh, and over 30 per cent of the villages in the regions around Delhi. It is thought that up to 11 million people may have died in the two famines.
Document 8: Harvard University: Established originally by the Massachusetts legislature and soon thereafter named for John Harvard (its first benefactor), Harvard is the United States' oldest institution of higher learning, and the Harvard Corporation (formally, the President and Fellows of Harvard College) is its first chartered corporation. Although never formally affiliated with any denomination, the early College primarily trained Congregationalist and Unitarian clergy. Its curriculum and student body were gradually secularized during the 18th century, and by the 19th century Harvard had emerged as the central cultural establishment among Boston elites. Following the American Civil War, President Charles W. Eliot's long tenure (1869–1909) transformed the college and affiliated professional schools into a modern research university; Harvard was a founding member of the Association of American Universities in 1900. James Bryant Conant led the university through the Great Depression and World War II and began to reform the curriculum and liberalize admissions after the war. The undergraduate college became coeducational after its 1977 merger with Radcliffe College.
Document 9: Oklahoma: During the 1930s, parts of the state began suffering the consequences of poor farming practices, extended drought and high winds. Known as the Dust Bowl, areas of Kansas, Texas, New Mexico and northwestern Oklahoma were hampered by long periods of little rainfall and abnormally high temperatures, sending thousands of farmers into poverty and forcing them to relocate to more fertile areas of the western United States. Over a twenty-year period ending in 1950, the state saw its only historical decline in population, dropping 6.9 percent as impoverished families migrated out of the state after the Dust Bowl.
Document 10: Amazon rainforest: For a long time, it was thought that the Amazon rainforest was only ever sparsely populated, as it was impossible to sustain a large population through agriculture given the poor soil. Archeologist Betty Meggers was a prominent proponent of this idea, as described in her book Amazonia: Man and Culture in a Counterfeit Paradise. She claimed that a population density of 0.2 inhabitants per square kilometre (0.52/sq mi) is the maximum that can be sustained in the rainforest through hunting, with agriculture needed to host a larger population. However, recent anthropological findings have suggested that the region was actually densely populated. Some 5 million people may have lived in the Amazon region in AD 1500, divided between dense coastal settlements, such as that at Marajó, and inland dwellers. By 1900 the population had fallen to 1 million and by the early 1980s it was less than 200,000.
Document 11: Harvard University: The Harvard Business School and many of the university's athletics facilities, including Harvard Stadium, are located on a 358-acre (145 ha) campus opposite the Cambridge campus in Allston. The John W. Weeks Bridge is a pedestrian bridge over the Charles River connecting both campuses. The Harvard Medical School, Harvard School of Dental Medicine, and the Harvard School of Public Health are located on a 21-acre (8.5 ha) campus in the Longwood Medical and Academic Area approximately 3.3 miles (5.3 km) southwest of downtown Boston and 3.3 miles (5.3 km) south of the Cambridge campus.
Document 12: Harvard University: Harvard's 2,400 professors, lecturers, and instructors instruct 7,200 undergraduates and 14,000 graduate students. The school color is crimson, which is also the name of the Harvard sports teams and the daily newspaper, The Harvard Crimson. The color was unofficially adopted (in preference to magenta) by an 1875 vote of the student body, although the association with some form of red can be traced back to 1858, when Charles William Eliot, a young graduate student who would later become Harvard's 21st and longest-serving president (1869–1909), bought red bandanas for his crew so they could more easily be distinguished by spectators at a regatta.
Document 13: Frederick Jackson Turner: Frederick Jackson Turner (November 14, 1861 – March 14, 1932) was an American historian in the early 20th century, based at the University of Wisconsin until 1910, and then at Harvard. He was primarily known for his “Frontier Thesis.” He trained many PhDs who came to occupy prominent places in the history profession. He promoted interdisciplinary and quantitative methods, often with a focus on the Midwest. He is best known for his essay "The Significance of the Frontier in American History", whose ideas formed the Frontier Thesis. He argued that the moving western frontier shaped American democracy and the American character from the colonial era until 1890. He is also known for his theories of geographical sectionalism. In recent years historians and academics have argued strenuously over Turner's work; all agree that the Frontier Thesis has had an enormous impact on historical scholarship and the American soul.
Document 14: Great Plains: The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land.
Document 15: Frederick Winslow Taylor: Frederick Winslow Taylor (March 20, 1856 -- March 21, 1915) was an American mechanical engineer who sought to improve industrial efficiency. He was one of the first management consultants. Taylor was one of the intellectual leaders of the Efficiency Movement and his ideas, broadly conceived, were highly influential in the Progressive Era (1890s - 1920s). Taylor summed up his efficiency techniques in his 1911 book The Principles of Scientific Management, which in 2001 Fellows of the Academy of Management voted the most influential management book of the twentieth century. His pioneering work in applying engineering principles to the work done on the factory floor was instrumental in the creation and development of the branch of engineering that is now known as industrial engineering. Taylor made his name in, and was most proud of his work in, scientific management; however, he made his fortune patenting steel - process improvements. Taylor was also an athlete who competed nationally in tennis and golf.
ground_truth: 7,200
sub_queries: who declated the American frontier "closed" in 1893? Answer: Frederick Jackson Turner
Frederick Jackson Turner >> employer Answer: Harvard
What is the enrollment of undergraduates at Harvard ? Answer: 7,200