Is Response-to-Intervention Good Policy for Specific Learning Disability?

The reauthorized Individuals with Disabilities Education Improvement Act (IDEA, 2004) established new provisions for specific learning disability (SLD) identification, including: (a) no longer requiring consideration of IQ-achievement discrepancy, and (b) permitting response-to-intervention (RTI) as part of SLD evaluation procedures. We discuss several policy implications of these new regulations by considering the original construct of SLD, the still “experimental” status and implementation of RTI, the closer alignment of RTI objectives with No Child Left Behind (NCLB, 2001) than former IDEA regulations, and the shift in focus from serving as a special education identification procedure to a general education instructional procedure. We conclude by proposing several recommendations for the appropriate inclusion of both RTI and psychometric evaluation within the continuum of SLD identification procedures

A Time to Define: Making the Specific Learning Disability Definition Prescribe Specific Learning Disability

Unlike other special education categories defined in U.S. law (Individuals with Disabilities Education Act), the definition of specific learning disability (SLD) has not changed since first proposed in 1968. Thus, although the operational definition of SLD has responded to new knowledge and understanding about the construct, the formal definition has remained static for 40 years, creating a schism between theory and practice. Using concepts gleaned from the scientific study of formal and operational definitions as well as the history of another special education category (i.e., mental retardation), in this article we demonstrate why change in the SLD definition is necessary. Finally, we propose a change in the SLD definition in federal regulations to redress the disconnect between theory and practice and restore integrity to the SLD field

Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers

Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers

A New Technique for Firn Grain-Size Measurement Using SEM Image Analysis

Firn microstructure is accurately characterized using images obtained from scanning electron microscopy (SEM). Visibly etched grain boundaries within images are used to create a skeleton outline of the microstructure. A pixel-counting utility is applied to the outline to determine grain area. Firn grain sizes calculated using the technique described here are compared to those calculated using the techniques of Cow (1969) and Gay and Weiss (1999) on samples of the same material, and are found to be substantially smaller. The differences in grain size between the techniques are attributed to sampling deficiencies (e.g. the inclusion of pore filler in the grain area) in earlier methods. The new technique offers the advantages of greater accuracy and the ability to determine individual components of the microstructure (grain and pore), which have important applications in ice-core analyses. The new method is validated by calculating activation energies of grain boundary diffusion using predicted values based on the ratio of grain-size measurements between the new and existing techniques. The resulting activation energy falls within the range of values previously reported for firn/ice

Hydroacoustic Assessment of Abundance and Diel Distribution of Sockeye Salmon and Kokanee in the Sawtooth Valley Lakes, Idaho

We used dual-beam hydroacoustics and echo integration techniques, combined with midwater trawling and gillnetting, to assess the abundance and distribution of the endangered Snake River juvenile sockeye salmon and resident kokanee (both Oncorhynchus nerka) in Sawtooth Valley lakes of Idaho during September 1991 and 1992. Abundance of O. nerka varied among the four lakes containing this species (12,500–257,000) and varied between years in Redfish Lake (86,400 in 1994 and 241,000 in 1992) and Alturas Lake (230,000 in 1991 and 257,000 in 1992). In Alturas Lake, where piscivore densities were high and zooplankton densities were low, small acoustic targets (≤18 cm long) were nearly absent from the limnetic zone during daylight, and high densities remained in colder intermediate depths (15–30 m) during crepuscular and nocturnal periods. In Redfish Lake, where predator density was much lower and zooplankton density was higher, targets concentrated in schools at 25–30 m during daylight, dispersed into the upper 10 m at dusk, then were broadly distributed over the upper 30 m at night. In Pettit and Stanley lakes, nocturnal distributions of smaller (3–7 cm) and intermediate (7–18 cm) target sizes were skewed toward the epilimnion, and larger targets remained in the metalimnion or upper hypolimnion. The different diel vertical distribution patterns suggested that juvenile O. nerka exposed to limited food and high predation risk consumed smaller rations and maximized bioenergetic efficiency. Populations with higher food supplies and exposed to lower piscivore densities exploited the higher epilimnetic prey densities and temperatures at night and crepuscular periods to maximize growth but deviated further from bioenergetic efficiency. Populations responded differently to the unique combination of constraints that limit potential sockeye salmon smolt production at each lake. Consequently, different management strategies may be needed in each lake

Characterizing Family Physicians Who Refer to Telepsychiatry in Ontario

INTRODUCTION: Telepsychiatry can improve access to psychiatric services for those who otherwise cannot easily access care. Family physicians are gatekeepers to specialized care in Ontario, so it is essential to understand predictors relating to referrals to telepsychiatry to better plan services and increase telepsychiatry adoption. METHODS: This study used an annual retrospective cross-sectional study design to compare physicians who referred their patients to telepsychiatry each year from fiscal year (FY) 2008 to FY 2016. A 1-year (FY 2016) comparison of family physicians who referred to telepsychiatry (FPTs) compared to family physicians who did not refer to telepsychiatry (FPNTs) matched (1:2) by region was also conducted. Finally, we used statistical modeling to understand the predictors of referring to telepsychiatry among physicians. RESULTS: Between FY 2008 and FY 2016, the number of patients receiving telepsychiatry increased from 925 visits to 13,825 visits. Thirty-two percent of Ontario primary care physicians referred to telepsychiatry in 2016. Several characteristics were notably different between FPTs and FPNTs: FPTs were more likely to be from a residence with less than 10,000 people, to have more nurse practitioners in the practice, and to be from a family health team than FPNTs. Rostered patients of FPTs were more likely to reside in rural areas, have more clinical complexity, and to utilize more mental health services compared to FPNTs. CONCLUSIONS: There has been an increase in the use of telepsychiatry by patients and family physicians over the study period, although there remains opportunity for significant growth. Family physicians who live in rural areas, are part of an FHT, have more NPs, with more rural and complex patients were more likely to refer to telepsychiatry. As recent pro-telemedicine policies support the growth of telepsychiatry, this study will serve as an important baseline

A longitudinal and cross-sectional study of plasma neurofilament light chain concentration in Charcot-Marie-Tooth disease

Advances in genetic technology and small molecule drug development have paved the way for clinical trials in Charcot-Marie-Tooth disease (CMT); however, the current FDA-approved clinical trial outcome measures are insensitive to detect a meaningful clinical response. There is, therefore, a need to identify sensitive outcome measures or clinically relevant biomarkers. The aim of this study was to further evaluate plasma neurofilament light chain (NFL) as a disease biomarker in CMT. Plasma NFL was measured using SIMOA technology in both a cross-sectional study of a US cohort of CMT patients and longitudinally over 6 years in a UK CMT cohort. In addition, plasma NFL was measured longitudinally in two mouse models of CMT2D. Plasma concentrations of NFL were increased in a US cohort of patients with CMT1B, CMT1X and CMT2A but not CMT2E compared with controls. In a separate UK cohort, over a 6-year interval, there was no significant change in plasma NFL concentration in CMT1A or HSN1, but a small but significant reduction in patients with CMT1X. Plasma NFL was increased in wild type compared to GARSC201R mice. There was no significant difference in plasma NFL in GARSP278KY compared to wild type mice. In patients with CMT1A, the small difference in cross-sectional NFL concentration vs healthy controls and the lack of change over time suggests that plasma NFL may lack sufficient sensitivity to detect a clinically meaningful treatment response in adulthood