Making the most of clade selection

Clade selection is unpopular with philosophers who otherwise accept multilevel selection theory. Clades cannot reproduce, and reproduction is widely thought necessary for evolution by natural selection, especially of complex adaptations. Using microbial evolutionary processes as heuristics, I argue contrariwise, that (1) clade growth (proliferation of contained species) substitutes for clade reproduction in the evolution of complex adaptation, (2) clade-level properties favoring persistence – species richness, dispersal, divergence, and possibly intraclade cooperation – are not collapsible into species-level traits, (3) such properties can be maintained by selection on clades, and (4) clade selection extends the explanatory power of the theory of evolution

Improving the Economic and Life Outcomes of At-Risk Youth, Spring 2003

Outlines ideas and strategies for designing programs to engage alienated and disaffected young people in activities designed to help them acquire skills, gain work experience, and improve their lives. Proposes a specific major experimental program

Improving the Economic and Life Outcomes of At-Risk Youth, Fall 2002

This paper outlines ideas and strategies to engage alienated and disaffected young people and help them acquire skills, gain work experience, and improve their lives. Based on lessons learned from three decades of demonstrations and evaluations concerning at-risk youth, the paper presents ideas that government agencies and private foundations could consider when working to fill important service and knowledge gaps. It offers suggestions about how to change the public discourse about young people at risk and how to strengthen the public will to capitalize on this population's strengths and potential. The paper recommends three program strategies, all of which leverage youth-serving institutions and existing funding streams and lay the groundwork to expand programs whose effectiveness has stood the test of evaluation. The fundamental premise of this paper is how to increase youth engagement as a prerequisite to success. It draws upon existing research, the experiences of youth programs that have had unusual success in attracting and retaining enrollees, insights from a youth development perspective, and the observations of youth program practitioners and young people themselves. Recommendations are presented in the areas of goals and framework for action, program design, and broadening public support and building capacity

Origin and evolution of the slime molds (Mycetozoa)

The Mycetozoa include the cellular (dictyostelid), acellular (myxogastrid), and protostelid slime molds. However, available molecular data are in disagreement on both the monophyly and phylogenetic position of the group. Ribosomal RNA trees show the myxogastrid and dictyostelid slime molds as unrelated early branching lineages, but actin and ß-tubulin trees place them together as a single coherent (monophyletic) group, closely related to the animal–fungal clade. We have sequenced the elongation factor-1a genes from one member of each division of the Mycetozoa, including Dictyostelium discoideum, for which cDNA sequences were previously available. Phylogenetic analyses of these sequences strongly support a monophyletic Mycetozoa, with the myxogastrid and dictyostelid slime molds most closely related to each other. All phylogenetic methods used also place this coherent Mycetozoan assemblage as emerging among the multicellular eukaryotes, tentatively supported as more closely related to animals + fungi than are green plants. With our data there are now three proteins that consistently support a monophyletic Mycetozoa and at least four that place these taxa within the ‘‘crown’’ of the eukaryote tree. We suggest that ribosomal RNA data should be more closely examined with regard to these questions, and we emphasize the importance of developing multiple sequence data sets

Syntactic annotation of non-canonical linguistic structures

This paper deals with the syntactic annotation of corpora that contain both ‘canonical’ and ‘non-canonical’ sentences

How Children Used to Work

Discusses the changing role of children in the United States from 1800-1970, focusing on the increasing conflict between child rearing and other activities of parents, the curtailment of child labor, and the decreasing importance of children as a source of old-age financial support for their parents

The root of the universal tree and the origin of eukaryotes based on elongation factor phylogeny

The genes for the protein synthesis elongation factors Tu (EF-Tu) and G (EF-G) are the products of an ancient gene duplication, which appears to predate the divergence of all extant organismal lineages. Thus, it should be possible to root a universal phylogeny based on either protein using the second protein as an outgroup. This approach was originally taken independently with two separate gene duplication pairs, (i) the regulatory and catalytic subunits of the proton ATPases and (ii) the protein synthesis elongation factors EF-Tu and EF-G. Questions about the orthology of the ATPase genes have obscured the former results, and the elongation factor data have been criticized for inadequate taxonomic representation and alignment errors. We have expanded the latter analysis using a broad representation of taxa from all three domains of life. All phylogenetic methods used strongly place the root of the universal tree between two highly distinct groups, the archaeons/eukaryotes and the eubacteria. We also find that a combined data set of EF-Tu and EF-G sequences favors placement of the eukaryotes within the Archaea, as the sister group to the Crenarchaeota. This relationship is supported by bootstrap values of 60-89% with various distance and maximum likelihood methods, while unweighted parsimony gives 58% support for archaeal monophyly

A Review of the Physics of Comets and Its Experimental Investigation by an Instrumented Space Probe

Physics, chemistry, and cosmology review of comets and proposed space probe experiment