There is considerable concern that the majority of adolescents do not develop the competence in writing they need to be successful in school, the workplace, or their personal lives. A common explanation for why youngsters do not write well is that schools do not do a good job of teaching this complex skill. In an effort to identify effective instructional practices for teaching writing to adolescents, the authors conducted a meta-analysis of the writing intervention literature (Grades 4 -12), focusing their efforts on experimental and quasi-experimental studies. They located 123 documents that yielded 154 effect sizes for quality of writing. The authors calculated an average weighted effect size (presented in parentheses) for the following 11 interventions: strategy instruction (0.82), summarization (0.82), peer assistance (0.75), setting product goals (0.70), word processing (0.55), sentence combining (0.50), inquiry (0.32), prewriting activities (0.32), process writing approach (0.32), study of models (0.25), grammar instruction (-0.32).

The authors used multiple-group structural equation modeling to analyze structural relationships between latent factors underlying separate measures of handwriting, spelling, and composing in Grades 1-6. For compositional fluency, the paths from both handwriting and spelling were significant in the primary grades, but only the path from handwriting was significant in the intermediate grades. For compositional quality, only the path from handwriting was significant at the primary and intermediate grades. The contribution of spelling to compositional quality was indirect through its correlation with handwriting. Handwriting and spelling accounted for a sizable proportion of the variance in compositional fluency (41 % to 66%) and compositional quality (25% to 42%). These findings show that the mechanical skills of writing may exert constraints on amount and quality of composing. Theoretical and educational implications of the findings are discussed.Mechanical requirements for producing text have been hypothesized to contribute to individual differences in writing performance in several important ways (Berninger et al., 1992;Graham, 1990;Scardamalia, Bereiter, & Goleman, 1982). For persons who have not yet mastered the mechanics of writing, having to attend to the lower level skills of getting language onto paper may "tax" a writer's processing capacity in working memory, interfering with higher order skills such as planning and content generation. Having to switch attention during composing to mechanical demands, such as figuring out how to spell a word, may lead the writer to forget already developed ideas and plans. Simultaneously allocating attention to mechanical concerns while trying to plan the next unit of text may further interfere with the planning process, affecting the complexity and coherence of content integration. If attention is occupied with mechanical concerns, the writer may also have less opportunity to make expressions more precisely fit intentions at the point of translation. Finally, the writer's fluency with handwriting (or typing) may not be fast enough to keep up with his or her thoughts, interfering with content generation and recall of ideas or text already planned and held in working memory. However, the empirical research on the relationship between the mechanics of production and the composing process has yielded mixed results, depending on age and

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We have established Meloidogyne hapla as a tractable model plant-parasitic nematode amenable to forward and reverse genetics, and we present a complete genome sequence. At 54 Mbp, M. hapla represents not only the smallest nematode genome yet completed, but also the smallest metazoan, and defines a platform to elucidate mechanisms of parasitism by what is the largest uncontrolled group of plant pathogens worldwide. The M. hapla genome encodes significantly fewer genes than does the freeliving nematode Caenorhabditis elegans (most notably through a reduction of odorant receptors and other gene families), yet it has acquired horizontally from other kingdoms numerous genes suspected to be involved in adaptations to parasitism. In some cases, amplification and tandem duplication have occurred with genes suspected of being acquired horizontally and involved in parasitism of plants. Although M. hapla and C. elegans diverged >500 million years ago, many developmental and biochemical pathways, including those for dauer formation and RNAi, are conserved. Although overall genome organization is not conserved, there are areas of microsynteny that may suggest a primary biological function in nematodes for those genes in these areas. This sequence and map represent a wealth of biological information on both the nature of nematode parasitism of plants and its evolution.compaction ͉ dauer ͉ development ͉ horizontal gene transfer ͉ gene N ematodes are an abundant and species-rich animal phylum.They share a common body plan on which various adaptations have evolved, enabling Nematoda to occupy essentially all ecological niches, including being parasites of many other organisms (1). Parasitism of plants appears to have arisen independently in three of the major 12 nematode clades (2) and results in annual losses to world agriculture estimated to exceed $US100 billion (3, 4). The majority of damage is caused by sedentary endoparasitic forms in the order Tylenchida, which includes the root-knot nematodes (Meloidogyne spp., RKN). RKN have a cosmopolitan distribution and a host range that spans most crops, although individual RKN species exhibit a more restricted host range. Mature female RKN release hundreds of eggs onto the surface of the root that hatch in the soil as second-stage larvae (L2) and typically reinfect the same plant. RKN L2 are similar in function to dauer larvae (5), which were first described as an adaptation to parasitism to overcome adverse environmental conditions and facilitate dispersal (6), but have been best studied in the free-living nematode Caenorhabditis elegans (7). These larvae are developmentally arrested, motile, nonfeeding, nonaging, and long-lived. Like C. elegans dauers, RKN L2 are detergent-resistant (5), use the glyoxylate pathway (8), and exhibit intestinal morphology with sparse luminal microvilli and numerous lipid storage vesicles that permit long-term survival in the soil. RKN L2 penetrate the root and migrate intercellularly into the vascular cylinder. Migration is accompanied by extensive ...

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Almost 700 children were screened to identify 144 1st graders at risk for handwriting problems who were randomly assigned to 1 of 6 treatment conditions. Treatment was delivered to groups of 3 that met twice a week in 20-min sessions until they completed 24 lessons. Five groups received 10 min of different kinds of handwriting instruction. The contact control group received 10 min of phonological awareness training. All 6 groups composed and shared their writing for 10 min. Converging evidence across multiple measures showed that combining numbered arrows and memory retrieval was the most effective treatment for improving both handwriting and compositional fluency (composing with time limits). Thus instruction aimed at improving transcription transfers to improved text generation in beginning writers.

Writing development involves changes that occur in children’s strategic behavior, knowledge, and motivation. The authors examined the effectiveness of self-regulated strategy development (SRSD), a strategy instructional model designed to promote development in each of these areas. Instruction focused on planning and writing stories and persuasive essays. The addition of a peer support component to SRSD instruction aimed at facilitating maintenance and generalization effects was also examined. SRSD had a positive impact on the writing performance and knowledge of struggling second-grade writers attending urban schools serving a high percentage of low-income families. In comparison with children in the Writers’ Workshop condition, SRSD-instructed students were more knowledgeable about writing and evidenced stronger performance in the two instructed genres (story and persuasive writing) as well as two uninstructed genres (personal narrative and informative writing). Moreover, the peer support component augmented SRSD instruction by enhancing specific aspects of students’ performance in both the instructed and uninstructed genres.

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