123 research outputs found
The Vegetation of the Paleozoic Plateau, Northeastern Iowa
The present vegetation of the Paleozoic Plateau region of Iowa is a fragmented representation of the original complex of oak-hickory forest mixed with more mesophytic forest, open oak savanna and hill prairie. Because of the topographic variation and the relatively cool, moist environment of the region, the forests are the best developed of those in Iowa, and show the greatest variation, including two types of alluvial forests (Salix thickets and alluvial hardwood forest), and several kinds of upland forests (Tilia, Acer, Quercus borealis, Q, alba and Pinus forests). These types represent points along a more-or-less continuous topographic gradient. Many of the native oak savannas have been eliminated, but oak-juniper glades may be found on cliff faces and steep ridges. The remaining hill prairies are rich in species characteristic of the dry prairies farther to the west. Cold, north-facing slopes ( algific slopes ) are the setting for a unique community containing a large number of rare and disjunct species. Outcrops of sandstones and limestone have characteristic microcommunities, often distinguished by their bryophyte or pteridophyte flora. There is a dearth of quantitative vegetation data from the region, and there are numerous research questions about the communities and their plant species that need answers. Preservation and conservation of plant communities and plant species are extremely important and should be addressed by a landscape approach to inventory and management
Ecological distribution and population physiology defined by proteomics in a natural microbial community
Community proteomics applied to natural microbial biofilms resolves how the physiology of different populations from a model ecosystem change with measured environmental factors in situ.The initial colonists, Leptospirillum Group II bacteria, persist throughout ecological succession and dominate all communities, a pattern that resembles community assembly patterns in some macroecological systems.Interspecies interactions, and not abiotic environmental factors, demonstrate the strongest correlation to physiological changes of Leptospirillum Group II.Environmental niches of subdominant populations seem to be determined by combinations of specific sets of abiotic environmental factors
The importance of understanding individual differences in Down syndrome
In this article, we first present a summary of the general assumptions about Down syndrome (DS) still to be found in the literature. We go on to show how new research has modified these assumptions, pointing to a wide range of individual differences at every level of description. We argue that, in the context of significant increases in DS life expectancy, a focus on individual differences in trisomy 21 at all levels—genetic, cellular, neural, cognitive, behavioral, and environmental—constitutes one of the best approaches for understanding genotype/phenotype relations in DS and for exploring risk and protective factors for Alzheimer’s disease in this high-risk population
The theory of expanded, extended, and enhanced opportunities for youth physical activity promotion
Background Physical activity interventions targeting children and adolescents (≤18 years) often focus on complex intra- and inter-personal behavioral constructs, social-ecological frameworks, or some combination of both. Recently published meta-analytical reviews and large-scale randomized controlled trials have demonstrated that these intervention approaches have largely produced minimal or no improvements in young people\u27s physical activity levels.
Discussion In this paper, we propose that the main reason for previous studies\u27 limited effects is that fundamental mechanisms that lead to change in youth physical activity have often been overlooked or misunderstood. Evidence from observational and experimental studies is presented to support the development of a new theory positing that the primary mechanisms of change in many youth physical activity interventions are approaches that fall into one of the following three categories: (a) the expansion of opportunities for youth to be active by the inclusion of a new occasion to be active, (b) the extension of an existing physical activity opportunity by increasing the amount of time allocated for that opportunity, and/or (c) the enhancement of existing physical activity opportunities through strategies designed to increase physical activity above routine practice. Their application and considerations for intervention design and interpretation are presented.
Summary The utility of these mechanisms, referred to as the Theory of Expanded, Extended, and Enhanced Opportunities (TEO), is demonstrated in their parsimony, logical appeal, support with empirical evidence, and the direct and immediate application to numerous settings and contexts. The TEO offers a new way to understand youth physical activity behaviors and provides a common taxonomy by which interventionists can identify appropriate targets for interventions across different settings and contexts. We believe the formalization of the TEO concepts will propel them to the forefront in the design of future intervention studies and through their use, lead to a greater impact on youth activity behaviors than what has been demonstrated in previous studies
太平洋地域における大陸と島嶼の森林の種多様性
Alpha diversity, or species richness, of East Asian mainland evergreen broadleaved forests, expressed by indices of Fisher\u27s alpha (agr) and S(100), a new index showing species number in a 100-individual sample, is significantly correlated with the climatic favorableness, expressed by Kira\u27s warmth index. On the contrary, diversity values of insular forests studied on Kyushu satellites of Japan, the Bonins, the Eastern Carolines of Micronesia, and the Galapagos in the eastern Pacific, are below those expected from the climate of respective oceanic islands. Species-individual curves, comparing mainland-and insular communities, also support clearly the above conclusion of species poverty in the insular communities studied.The original publication is available at www.springerlink.co
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