Arizona State University

About: Arizona State University is a education organization based out in Tempe, Arizona, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 40425 authors who have published 109662 publications receiving 4488331 citations. The organization is also known as: Arizona State & ASU Tempe.

Isoetalean Lycopsid Evolution: from the Devonian to the Present

Abstract: The evolution of the isoetalean lycopsids spans much of the history of vascular plants, from Late, (or possibly Middle), Devonian to the current day genus Isoetes. The best known fossil members of this group are the arborescent lepidodendrids that dominated the Late Carboniferous coal swamps. Simpler unbranched isoetaleans with elongate stems also predated, coexisted with, and postdated the coal swamp trees, extending well into the Mesozoic. Whereas certain synapomorphies such as stigmarian rootlets, bipolar growth and secondary tissues unite the clade, other features characterize smaller subgroups of differing age, growth form and possibly, evolutionary lineage. Although some of these features are well known for plants of given time periods, particularly the Carboniferous, trends in character evolution have never been adequately documented for the group as a whole. A better understanding of such trends throughout the isoetalean fossil record could be valuable in distinguishing evolutionary lineages from convergence. It is interesting that several morphological characters of modern Isoetes are present as early as the Triassic: monolete microspores, sunken sporangia and elaborate ligules with glossopodia occur within elongate-stemmed Triassic forms. The dominant plant habit of modern Isoetes, a reduced cormose form that lacks appreciable stem elongation, originated at least by the Jurassic and typifies late Mesozoic and Cenozoic isoetaleans.

The Effects of Positive and Negative Parenting Practices on Adolescent Mental Health Outcomes in a Multicultural Sample of Rural Youth

Abstract: The quality of parent–child relationships has a significant impact on adolescent developmental outcomes, especially mental health. Given the lack of research on rural adolescent mental health in general and rural parent–child relationships in particular, the current longitudinal study explores how rural adolescents’ (N = 2,617) perceptions of parenting practices effect their mental health (i.e., anxiety, depression, aggression, self-esteem, future optimism, and school satisfaction) over a 1 year period. Regression models showed that current parenting practices (i.e., in Year 2) were strongly associated with current adolescent mental health outcomes. Negative current parenting, manifesting in parent–adolescent conflict, was related to higher adolescent anxiety, depression, and aggression and lower self-esteem, and school satisfaction. Past parent–adolescent conflict (i.e., in Year 1) also positively predicted adolescent aggression in the present. Current positive parenting (i.e., parent support, parent–child future orientation, and parent education support) was significantly associated with less depression and higher self-esteem, future optimism, and school satisfaction. Past parent education support was also related to current adolescent future optimism. Implications for practice and limitations were discussed.

Efficiency of the neighbor-joining method in reconstructing deep and shallow evolutionary relationships in large phylogenies

Abstract: The neighbor-joining (NJ) method is widely used in reconstructing large phylogenies because of its computational speed and the high accuracy in phylogenetic inference as revealed in computer simulation studies. However, most computer simulation studies have quantified the overall performance of the NJ method in terms of the percentage of branches inferred correctly or the percentage of replications in which the correct tree is recovered. We have examined other aspects of its performance, such as the relative efficiency in correctly reconstructing shallow (close to the external branches of the tree) and deep branches in large phylogenies; the contribution of zero-length branches to topological errors in the inferred trees; and the influence of increasing the tree size (number of sequences), evolutionary rate, and sequence length on the efficiency of the NJ method. Results show that the correct reconstruction of deep branches is no more difficult than that of shallower branches. The presence of zero-length branches in realized trees contributes significantly to the overall error observed in the NJ tree, especially in large phylogenies or slowly evolving genes. Furthermore, the tree size does not influence the efficiency of NJ in reconstructing shallow and deep branches in our simulation study, in which the evolutionary process is assumed to be homogeneous in all lineages.

How Much Physical Activity is Enough

Abstract: (1996). How Much Physical Activity is Enough? Journal of Physical Education, Recreation & Dance: Vol. 67, No. 4, pp. 33-37.