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There is now solid experimental evidence of at least one supernova explosion within 100 pc of Earth within the last few million years, from measurements of the short-lived isotope 60Fe in widespread deep-ocean samples, as well as in the lunar regolith and cosmic rays. This is the first established example of a specific dated astrophysical event outside the Solar System having a measurable impact on the Earth, offering new probes of stellar evolution, nuclear astrophysics, the astrophysics of the solar neighborhood, cosmic-ray sources and acceleration, multi-messenger astronomy, and astrobiology. Interdisciplinary connections reach broadly to include heliophysics, geology, and evolutionary biology. Objectives for the future include pinning down the nature and location of the established near-Earth supernova explosions, seeking evidence for others, and searching for other short-lived isotopes such as 26Al and 244Pu. The unique information provided by geological and lunar detections of radioactive 60Fe to assess nearby supernova explosions make now a compelling time for the astronomy community to advocate for supporting multi-disciplinary, cross-cutting research programs., Comment: 11 pages, 2 figures. Astro2020 Science White Paper submitted to the 2020 Decadal Survey on Astronomy and Astrophysics

This paper summarizes a 22-month ethnographic study of rural Shandon (California), a community that demonstrates the social and demographic changes resulting from agricultural intensification in rural California. Changes in the Shandon area's agricultural production have produced a demographic shift from the homogeneous Anglo-American farming and ranching community of the 1960s to the current heterogeneous community, where over one-third of the population consists of Mexican-American farm laborers producing high value, labor intensive, specialty crops. This shift was documented by school district records. A strong ethnic boundary separates Shandon's American and Mexican communities, but flagrant systematic discrimination is found only in the rental housing market. Children of both groups readily cross the ethnic boundary, influenced by systematic integration and small class size in Shandon schools. Consequently, Mexican-American children have graduation rates and occupational mobility equivalent to Anglo children. Because of low wages, a prosperous agriculture in California actually has added to the number of local poor, and has done so in the form of an ethnically distinct immigrant population. In areas similar to Shandon, the scale and composition of foreign immigration stimulate a nativist reaction and increase ethnic tensions in the absence of racially divided labor markets, racially based systems of exploitation and discrimination, or economic crises. (RAH)