Estimating dissolved reactive phosphorus concentration in surface runoff water from major Ontario soils.

Phosphorus (P) loss from agricultural land in surface runoff can contribute to eutrophication of surface water. This study was conducted to evaluate a range of environmental and agronomic soil P tests as indicators of potential soil surface runoff dissolved reactive P (DRP) losses from Ontario soils. The soil samples (0- to 20-cm depth) were collected from six soil series in Ontario, with 10 sites each to provide a wide range of soil test P (STP) values. Rainfall simulation studies were conducted following the USEPA National P Research Project protocol. The average DRP concentration (DRP30) in runoff water collected over 30 min after the start of runoff increased (p < 0.001) in either a linear or curvilinear manner with increases in levels of various STPs and estimates of degree of soil P saturation (DPS). Among the 16 measurements of STPs and DPSs assessed, DPS(M3) 2 (Mehlich-3 P/[Mehlich-3 Al + Fe]) (r2 = 0.90), DPS(M3)-3 (Mehlich-3 P/Mehlich-3 Al) (r2 = 0.89), and water-extractable P (WEP) (r2 = 0.89) had the strongest overall relationship with runoff DRP30 across all six soil series. The DPS(M3)-2 and DPS(M3)-3 were equally accurate in predicting runoff DRP30 loss. However, DPS(M3)-3 was preferred as its prediction of DRP30 was soil pH insensitive and simpler in analytical procedure, ifa DPS approach is adopted.

Scaffolding: a broader view.

To situate the concept of scaffolding within a broader context than that addressed by Stone, I discuss it with respect to (a) the historical context of learning disabilities, (b) the emerging focus on learners' activity, (c) the reification of learning disabilities, and (d) the unintended effects that frequently occur as a by-product of injudicious (and often unintentional) scaffolding. I conclude that the effective practice of special education has been inhibited by our isolation of interventions from the theories that give rise to them, and by the way we structure teacher education. Although scaffolding is not the answer to correcting these problems, it may serve to refocus our attention and efforts in useful ways.

Anna's story: narratives of personal experience about being labeled learning disabled.

The narratives of personal experience of an adolescent named Anna provided insights into two issues: first, how well her discourse conformed to linguistic expectations for the types of narrative traditionally deemed acceptable in school, and second, the themes associated with the presentation of self that Anna and her peers addressed when talking about their personal experiences as students labeled learning disabled. By narrative, we mean the root metaphor for human sense-making that is described in the following epigraph by Bruner. We found that Anna's narrative differed from typical school-based expectations in that its structure was reminiscent of the oral tradition. From the group of students, we heard themes of isolation, undervaluing, and oppression. We recommend a more thoughtful and respectful approach to educational decision making that gives voice to students.

Differences that make a difference: comparisons of metacomponential functioning and knowledge base among groups of high and low IQ learning disabled, mildly mentally retarded, and normally achieving adults.

To determine if cognition among persons with learning disabilities (LD) and mild mental retardation (MMR) is similar, we compared metacomponential functioning and knowledge acquisition across groups of incarcerated adults with LD and high IQ (HIQLD), with LD and low IQ (LIQLD), with normal achievement (NA), and with MMR. The Slosson Intelligence Test Computer Report (Nicholson, 1984) formula established criteria for group inclusion. Metacomponential functioning among 77 males and 26 females was measured by a confidence test (Echternacht, Boldt, & Sellman, 1971) designed for the general knowledge subtest of the SRA Achievement Battery (Naslund, Thorpe, & Lefever, 1982). Knowledge base and group membership were significantly related to metacomponential ability (R2 = .84). Persons with HIQLD and LIQLD performed better than those with MMR on both measures. The HIQLD, however, did not outperform their peers with NA. Results show that (a) knowledge base is the best predictor of metacomponential skill, (b) metacomponential orchestration differentiates persons with HIQLD from those with LIQLD and both groups from persons with MMR, and (c) IQ mediates metacognition, but does not explain it. Education should emphasize knowledge acquisition for people with HIQLD; people with LIQLD and MMR require more attention to metacognition.