5,578 research outputs found

    Slow carbon and nutrient accumulation in trees established following fire exclusion in the southwestern United States.

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    Increasing tree density that followed fire exclusion after the 1880s in the southwestern United States may have also altered nutrient cycles and led to a carbon (C) sink that constitutes a significant component of the U.S. C budget. Yet, empirical data quantifying century-scale changes in C or nutrients due to fire exclusion are rare. We used tree-ring reconstructions of stand structure from five ponderosa pine-dominated sites from across northern Arizona to compare live tree C, nitrogen (N), and phosphorus (P) storage between the 1880s and 1990s. Live tree biomass in the 1990s contained up to three times more C, N, and P than in 1880s. However, the increase in C storage was smaller than values used in recent U.S. C budgets. Furthermore, trees that had established prior to the 1880s accounted for a large fraction (28-66%) of the C, N, and P stored in contemporary stands. Overall, our century-scale analysis revealed that forests of the 1880s were on a trajectory to accumulate C and nutrients in trees even in the absence of fire exclusion, either because growing conditions became more favorable after the 1880s or because forests in the 1880s included age or size cohorts poised for accelerated growth. These results may lead to a reduction in the C sink attributed to fire exclusion, and they refine our understanding of reference conditions for restoration management of fire-prone forests

    "Personality and Earnings"

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    This paper studies personality as a potential explanation for wage differentials between apparently similar workers. This follows initial studies by Jencks (1979) that suggest that certain personality traits, such as industriousness and leadership, have an impact on earnings. The paper aims to provide a theoretical framework within which these effects may be analyzed. The study begins by outlining four issues as a backdrop to the model: rationality, the industry, firms, and workers. A crucial factor to the model is the memeÑa mental gene that affects personality. Taking these four factors into consideration, the Contested Exchange model from Bowles and Gintis (1990) is used. Then, it is adapted to study memetic effects on the wage rate. This is followed by an analysis of how memes may affect personality and thus earnings. The issues that require further study and resolution are 1) which traits create wage differentials, and 2) two-way causality: does personality affect the wage, or does a wage premium become an incentive for a person to adopt new memes?

    The Campaign To Establish A Last Great Wilderness: The Arctic National Wildlife Range

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    Thesis (Ph.D.) University of Alaska Fairbanks, 2005In 1960, after nearly a decade of controversy and failed legislative attempts, the Arctic National Wildlife Range was established by an executive order "for the purpose of preserving unique wildlife, wilderness, and recreational values." This is the story of the transformation of this little-known expanse of mountains, forest, and tundra into a place internationally recognized as one of the finest examples of wilderness. This dissertation is a political history of the conflict, examining the roles of key proponents and opponents and the sequence of actions that finally brought the Secretary of Interior to issue the order. More important, it is an exploration of the historic, cultural, philosophical, and scientific underpinnings of the campaign. It focuses upon the beliefs and values, the ideas and idealism, and the hopes and concerns for the future that inspired leaders of the effort, captured the public imagination, and galvanized the political support necessary to overcome powerful opposition. The immediate context of the campaign was the post-World War II transformation of American society. More than in any previous period, postwar America was receptive to the idea of setting an area aside for a unique combination of tangible and intangible values---cultural, symbolic, and spiritual values as well as wildlife, ecological, and recreational values. The controversy reflected growing concerns about the era's unprecedented rate of population growth; economic, industrial, and technological expansion; and consequent environmental alteration. For proponents, it came to symbolize the conflict between seemingly unbridled progress and the need to more carefully consider the environmental consequences of these trends. For opponents, the nine-million acre reservation represented a threat to the new state's economic prosperity, resented federal control of natural resources, and a restriction of the opportunity and freedom they came to Alaska seeking. Rooted in the progressive era split between utilitarian conservation and nature preservation, the campaign was, to a large degree, a contest between competing views of the appropriate relationship between postwar American society and its changing landscape. The view that prevailed reflects the successful integration of the emerging ecologically-based "environmental" perspective into the wilderness movement

    Silverwire Newsletter

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    The Silverwire Newsletter is a triannual publication that highlights the work of the UMaine Center on Aging. The topics covered in this edition of the Silverwire Newsletter include successful aging for LGBT adults, research on local elder housing needs, and new Center on Aging staff

    Silverwire Newsletter

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    The Silverwire Newsletter is a triannual publication that highlights the work of the UMaine Center on Aging. The topics covered in this edition of the Silverwire Newsletter include the visiting Geriatric Scholar program, the Maine Gerontological society annual meeting, and recent research publications by the Center of Aging and it\u27s affiliate programs

    Silverwire

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    The Silverwire Newsletter is a quarterly publication that highlights the work of the UMaine Center on Aging. The topics covered in this edition of the Silverwire Newsletter include Dr. Len Kaye\u27s congressional testimony on the subject of social isolation, the Age Friendly Bangor final report, and recent projects undertaken by the Retired Senior Volunteer Corps

    Silverwire Newsletter

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    The Silverwire Newsletter is a triannual publication that highlights the work of the UMaine Center on Aging. The topics covered in this edition of the Silverwire Newsletter include initial results from the Maine Medication disposal program, sexuality and aging, and the success of the Encorps summit

    Space processes for extended low-G testing

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    Results of an investigation of verifying the capabilities of space processes in ground based experiments at low-g periods are presented. Limited time experiments were conducted with the processes. A valid representation of the complete process cycle was achieved at low-g periods ranging from 40 to 390 seconds. A minimum equipment inventory, is defined. A modular equipment design, adopted to assure low cost and high program flexibility, is presented as well as procedures and data established for the synthesis and definition of dedicated and mixed rocket payloads

    Silverwire Newsletter

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    The Silverwire Newsletter is a triannual publication that highlights the work of the UMaine Center on Aging. The topics covered in this edition of the Silverwire Newsletter include the ME prescription medication disposal program, chronic pain in older adults, and upcoming events hosted by the University of Maine Center on Aging

    Silverwire

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    he Silverwire Newsletter is a triannual publication that highlights the work of the UMaine Center on Aging. The topics covered in this edition of the Silverwire Newsletter include the publication of findings from a year long study on substance abuse assessment, updates around the senior college program, and a summary of the Center on Aging\u27s volunteer work within the Bangor community
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