SELECTED AMERICAN VIOLIN WORKS AND THEIR EUROPEAN CONTEXT

For my dissertation, I did a study and performance of American violin works by Charles Ives, Aaron Copland, Leonard Bernstein, and John Corigliano, along with contemporaneous European works by Paul Hindemith, Bela Bartok, Igor Stravinsky, Sergei Prokofiev, and Francis Poulenc. The selected American violin works display the development of a distinctively American style and cover a significant formative period (1914-1963) of American classical music. I intend that the European works form a backdrop for setting in relief any distinctly American qualities possessed by the American works. This is because they cover a similar time period and have significant stylistic affinities and shared influences. My topic stems from a question, "What defines the American Sound?" I attempted to find the answer by looking at the time when American composers consciously searched for their identities, and declared their music to be distinctly American. I found that those distinctive qualities stemmed from three sources: folk music, jazz and hymns. Ives and Copland can be viewed as American in content for their inclusion of such elements, while Bernstein and Corigliano can also be considered as "ideologically American" for their adventurous and eclectic spirit. The simplicity derived from singing a hymn or crooning a popular song; the freedom inspired by jazz; the optimism of accepting all possibilities-these elements inform the common spirit that I found in the music of these four American composers. FIRST RECITAL Sonatafor Violin Solo Op.3112 (1924), Paul Hindemith (1895-1963) Suite Italiennefor Violin and Piano (1932), Igor Stravinsky (1882-1971) Sonatafor Violin and Piano (1963), John Corigliano (b.1938) SECOND RECITAL Second Sonatafor Violin and Piano (1914-17), Charles Ives (1874-1954) First Rhapsody for Violin and Piano (1928), Bela Bart6k (1881-1971) Violin Sonata No.1 infminor (1938-46), Sergei Prokofiev (1891-1953) THIRD RECITAL Nocturne for Violin and Piano (1926), Aaron Copland (1900-1990)Sonata for Violin and Piano, Op. 119 (1942-3, rev.1949), Francis Poulenc (1899-1963)Serenade (after Plato's "Symposium'') (1954) by Leonard Bernstein (1918-1990) The pianists were Sun Ha Yoon (Bart6k) and Grace Eunae Cho (all other repertoire).

Geography and Genetics of Ecological Speciation in Pea Aphids

During ecological speciation, divergent natural selection drives evolution of ecological specialization and genetic differentiation of populations on alternate environments. Populations diverging onto the same alternate environments may be geographically widespread, so that divergence may occur at an array of locations simultaneously. Spatial variation in the process of divergence may produce a pattern of differences in divergence among locations called the Geographic Mosaic of Divergence. Diverging populations may vary in their degree of genetic differentiation and ecological specialization among locations. My dissertation examines the pattern and evolutionary processes of divergence in pea aphids (Acyrthosiphon pisum) on alfalfa (Medicago sativa) and clover (Trifolium pretense). In Chapter One, I examined differences among North American aphid populations in genetic differentiation at nuclear, sequence-based markers and in ecological specialization, measured as aphid fecundity on each host plant. In the East, aphids showed high host-plant associated ecological specialization and high genetic differentiation. In the West, aphids from clover were genetically indistinguishable from aphids on alfalfa, and aphids from clover were less specialized. Thus, the pattern of divergence differed among locations, suggesting a Geographic Mosaic of Divergence. In Chapter Two, I examined genomic heterogeneity in divergence in aphids on alfalfa and clover across North America using amplified fragment length polymorphisms (AFLPs). The degree of genetic differentiation varied greatly among markers, suggesting that divergent natural selection drives aphid divergence in all geographic locations. Three of the same genetic markers were identified as evolving under divergent selection in the eastern and western regions, and additional divergent markers were identified in the East. In Chapter Three, I investigated population structure of aphids in North America, France, and Sweden using AFLPs. Aphids on the same host plant were genetically similar across many parts of their range, so the evolution of host plant specialization does not appear to have occurred independently in every location. While aphids on alfalfa and clover were genetically differentiated in most locations, aphids from alfalfa and clover were genetically similar in both western North America and Sweden. High gene flow from alfalfa onto clover may constrain divergence in these locations.