The authors examine the modernist underpinnings of traditional adult learning and development theories and evaluate elements of those theories through more contemporary lenses. Drawing on recent literature focused on "public pedagogy," the authors argue that much learning takes place outside of formal educational institutions. They look beyond modernist narratives of adult development and consider the possible implications for critical adult learning occurring in and through contemporary fragmented, digital, media-saturated culture.
To assess the effects of advanced age on the nonspecific antimicrobial activity of resident alveolar macrophages (AM), superoxide anion (O2-) release and the phagocytic and bactericidal capacity of cells from three genetically distinct murine strains were evaluated. In initial experiments, resident AM, obtained by bronchoalveolar lavage of pathogen-free adult female CD-1 mice and studied in suspension, were found to produce O2- spontaneously and in response to phorbol myristate acetate (PMA) snd unopsonized zymosan. Maximum quantities of O2- were released following stimulation with 1 microgram/ml PMA and by a particle-to-cell ratio of 100:1 with zymosan; responses to the agonists peaked between 60 and 90 min. Resident AM obtained from pathogen and disease-free senescent (18-26-month-old) female C57BL/6, BALB/c, and DBA/2 mice released significantly more O2- in response to both PMA and zymosan than did cells secured from adult (4-8-month-old) animals. In vivo, the capacity of AM from adult and senescent animals to phagocytose Streptococcus pneumoniae (unencapsulated strain) and Staphylococcus aureus was comparable, and although the cells from the senescent mice tended to be more efficient in their ability to kill internalized bacteria, statistically significant differences between the two groups were not observed. The results of these studies indicate that the enhanced susceptibility of the senescent host to infection of the lower respiratory tract cannot be attributed to age-related changes in the nonspecific antimicrobial activity of resident AM.
This is a taxonoinic revision of thv grass genus Dichanihclium as roproscntccl in the United States and Canada. Keys and descriptions are pnn'ided for the 45 taxa (26 species and 19 varieties) of the United States and Canada recognized by the writers. A total of 26 now conihinations and changes of status are proposed. Many species of the genns Dichanthehum {Panicum sul^genns DichanthcUum Hitchc. & Cliase) arc widespread through the eastern half of the United States and the center of diversity appears to be in southeastern North America. At least some species are present almost throughout the cool, subtropical and tropical regions of North America and the Caribbean, and a few species range throughout much of South America. The genus also is represented in the Hawaiian Islands. This publication represents the first major revision of the DichanthcUum grass group since the monograph of Panicum by Hitchcock and Chase in 1910. Linnaeus (1753), in Species Planiarum, described the first three species tliat arc included in tlie DichantheVium group, Paiucum (lichofomum, P, chndestinum, and P. htifoUum, Panicum dichotomum L, was designatc^d as tlie typtŝ pecies of Panicum subgenus DichanthcUum by Hitchcock & Chase (1910) and is herein accepted as the type of the genus DichanthcUum. Lamarck in 1798 described Panicum scoparium, P. hixifh)rum, P. nitidum, and P. nodifJorum\ the last two species are now submerged in synonymy under DichanthcUum dichotomum. Most of tlie subsequent naming of dichanthelia taxa was done by the following workers: Elliott 8, Vasey 14, Scribner 22, Ashe 48, Nash 44, and Hitchcock 15. Among tlie other early botanists who contributed names were Swartz, Pursh, Poiret, Schultes, Sprengel, Michaux, Kunth, Nees, Desvaux, A. Gray, Cluipman, Trinius, Torrey, Steudcl, Criscbach, and Fournicx In 1885, in a catalogue of tlie grasses of the United States, George Vasey listed 12 species of rosette-forming panicums. Four years later, in the first monograph of Panicum^ Vasey (1889) recognized 20 species and 18 varieties in this group. In Grasses of North America. Beal (1896), recognized only 13 species and 6 varieties. During the period 1893-1900, G. V. Nash and W. W. Ashe collected extensively throughout the Carolinas and Florida and named a total of 92 new rosette-forming panicums. In 1901 Scribner and Merrill prepared an amiotated list of the New England species of Panicum, and in this list most of the species of Nash and Ashe wt^e put in synonymy or retained as varieties.
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