Registry for Radiation Workers, and combined cohort ofnuclear workers in United States future analysis of the registry, which will incorporate all registered cohorts and updated dose histories (in-National cluding internal doses) and have a longer follow up, Atomic homb survivors"0 Registry for Radiation American will provide a firmer basis for deriving risk estimates Whole cohort Doses <_500 mSv Workers workers* from low dose and low dose rate exposures. Cohort size 75 991 95 217 35 933 Person years 2 185 000 1 218 000 705 000 From its inception the registry has been guided by an Collective dose (man Sv) 18 000 3 198 1 140 a Range of doses 0-4 or more 0-0-5 0-0-5 or more 0-0-5 or more avisory committee of eminent epidemiologists. We are Excess relative risk per Sv grateful to themi for their guidance over many years, to Sir

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We report the results of a study with 30 teachers designed to examine the effects of teacher knowledge on the achievement of struggling readers. We worked with teachers of grades three, four, and five during a 10-day intervention focused on literacy instruction and related linguistic knowledge, and we assessed their students' learning across the year. Hierarchical models of student outcomes indicated that lower-performing students in intervention classrooms showed significantly higher levels of performance at year end on all literacy measures, compared with their peers in control classrooms (n = 140). In addition, teacher's linguistic knowledge was related to improved student performance, regardless of condition. Additional analyses including all students (n = 718) indicated that benefits for the lower performing students in intervention classrooms were shared by their classmates, but to a more limited extent.

A test may be unfair when students with the same knowledge but from different demographic groups perform differently on its items. Identifying and addressing this differential item functioning (DIF) helps ensure a fair, unbiased test. This Research Methods paper will help biology education researchers identify DIF items in their assessments.