Arctic patterned-ground ecosystems: A synthesis of field studies and models along a North American Arctic Transect

Arctic landscapes have visually striking patterns of small polygons, circles, and hummocks. The linkages between the geophysical and biological components of these systems and their responses to climate changes are not well understood. The "Biocomplexity of Patterned Ground Ecosystems" project examined patterned-ground features (PGFs) in all five Arctic bioclimate subzones along an 1800-km trans-Arctic temperature gradient in northern Alaska and northwestern Canada. This paper provides an overview of the transect to illustrate the trends in climate, PGFs, vegetation, n-factors, soils, active-layer depth, and frost heave along the climate gradient. We emphasize the thermal effects of the vegetation and snow on the heat and water fluxes within patterned-ground systems. Four new modeling approaches build on the theme that vegetation controls microscale soil temperature differences between the centers and margins of the PGFs, and these in turn drive the movement of water, affect the formation of aggradation ice, promote differential soil heave, and regulate a host of system propel-ties that affect the ability of plants to colonize the centers of these features. We conclude with an examination of the possible effects of a climate wan-ning on patterned-ground ecosystems.

Understanding Impediments and Enablers to Physical Activity among African American Adults: A Systematic Review of Qualitative Studies

Objective: To systematically assess and summarize impediments and facilitating factors impacting physical activity participation among African American Adults. ^ Method: A systematic search of the literature was conducted, which included electronic databases, as well as reference list of relevant papers. Only qualitative studies which measured race and ethnicity and had African American as adult participants were included. The main themes and categories from the qualitative studies pertaining to impediments and facilitators to physical activity were identified and summarized, through descriptive meta-synthesis. ^ Result: Twenty nine qualitative studies were included. Twenty-one of the studies only focused on adult African American women, and the barriers and facilitators to physical activity as perceived by them. The biggest individual enabler towards physical activity was the positive health benefits associated with regular physical activity. Social support and easy access to parks and facilities were also identified as enablers. Barriers toward physical activity were lack of time, lack of motivation, long work hours, and physical disabilities. ^ Conclusions: The findings of this review study should be useful to those planning an intervention in African American communities. There is also a need for qualitative studies conducted only among African American men, to better understand their perspective on the facilitators and barriers to physical activity.^

The American way of business;

Mode of access: Internet.

The Afro-American school speaker and gems of literature : for school commencements, literary circles, debating clubs, and rhetoricals generally /

Includes index.

The American Indian in graduate studies; a bibliography of theses and dissertations.

Mode of access: Internet.

The American school geography : embracing a general view of mathematical, physical, and civil geography ; adapted to the capacities of children ; with an atlas /

Mode of access: Internet.

The American school geography, embracing a general view of mathematical, physical, and civil geography ... With an atlas.

Mode of access: Internet.

Ten years of American opera design at the Juilliard school of music;

Mode of access: Internet.

The common school and the Negro American; report of a social study made by Atlanta University under the patronage of the Trustees of the John F. Slater Fund, with the proceedings of the 16th annual Conference for the Study of the Negro Problems, held at Atlanta University, on Tuesday, May 30th, 1911,

"A select bibliography of common school education for Negro Americans": p. [9]-12.