Measure for Measure: A Critical Consumers' Guide to Reading Comprehension Assessments for Adolescents

A companion report to Carnegie's Time to Act, analyzes and rates commonly used reading comprehension tests for various elements and purposes. Outlines trends in types of questions, stress on critical thinking, and screening or diagnostic functions

Navigating the Middle Grades and Preparing Students for High School Graduation

This brief presents preliminary findings from an exploratory study of New York City students' transitions into, through, and out of the middle grades. Our analysis reveals that students' attendance and achievement in their early schooling (fourth grade) predict whether students are likely to graduate from high school many years later. Further, we find that many students begin the middle grades on-track to graduate high school but fall off this trajectory before the end of eighth grade. These findings suggest that teachers and administrators should pay close attention to students whose attendance and math achievement fall during the middle grades, as these students are particularly at risk for not graduating from high school on time

Substrate-Controlled Magnetism: Fe nanowires on vicinal Cu surfaces

Here we present a novel approach to control magnetic interactions in atomic-scale nanowires. Our ab initio calculations demonstrate the possibility to tune magnetic properties of Fe nanowires formed on vicinal Cu surfaces. Both intrawire and interwire magnetic exchange parameters are extracted from DFT calculations. This study suggests that the effective interwire magnetic exchange parameters exhibit Ruderman--Kittel--Kasuya--Yosida-like (RKKY) oscillations as a function of Fe interwire separation. The choice of vicinal Cu surface offers possibilities for controlling the magnetic coupling. Furthermore, an anisotropic Heisenberg model was used in Monte Carlo simulations to examine the stability of these magnetic configurations at finite temperature. The predicted critical temperatures of the Fe nanowires on Cu(422) and Cu(533) surfaces are well-above room temperature

Navigating the Middle Grades: Evidence from New York City

Educators have long asserted that the middle grade years (typically, grades six through eight) are a time of both great importance and vulnerability in students' K-12 schooling. Anecdotal and empirical evidence suggest that students encounter new social and emotional challenges, increased academic demands, and major developmental transitions during the middle grade years. In this study, we investigate whether and how students' achievement and attendance change between grade four and eight and identified moments during this period when students' achievement and attendance suggest that they will struggle to graduate from high school within four years

Microscale elastic properties of interphases in polymer matrix composites: correlating spatial mapping with cure history

Polymer matrix composites with textile reinforcement are used in a wide range of aerospace and industrial applications. Continuum mechanical predictions of the composite behaviors have been inaccurate and resorted to empirical corrections, because of the lack of polymer materials property information. The length scales involved make experimental measurement of the elastic properties of the matrix within fiber tows and proximity to individual fibers difficult. However, micro-Brillouin and Raman light scattering provide sufficiently high spatial resolution to probe the mechanical properties and chemical composition of the matrix, without interfering with the thermo-mechanical equilibrium of the material. The elastic properties of epoxy resin have been measured between and within the fiber tows of a composite with this technique, and compared to a bulk epoxy resin. Using this approach, the elastic properties have also been monitored in situ, during epoxy cure under different thermal and chemical conditions. To interpret and enhance these results, experiments are complemented with molecular dynamics simulations of the interface extrapolating findings to nanometer length scales. We observe that matrix materials in close proximity to fibers have a diminished elastic modulus compared with both bulk epoxy and material between tows. To explain the underlying reason for this finding we identify the extent to which residual stresses, chemical inhomogeneities, or purely structural rearrangements near the interface contribute to this effect. Finally, we correlate the spatial distribution of mechanical properties with the cure history

Cure kinetics and interfacial phenomena in polymer matrix composites

Polymer matrix composites with textile reinforcement are used in a wide range of aerospace and industrial applications. Continuum mechanical predictions of the composite behaviors have been inaccurate, possibly because of the lack of information with regard to polymer materials properties, especially near the interfaces with the reinforcing fibers. Concurrent micro-Brillouin and Raman light scattering provides sufficiently high spatial resolution to probe the mechanical properties and chemical composition of the interphase regions of the matrix, without interfering with the thermo-mechanical equilibrium of the material. Using this technique, we mapped the elastic properties of epoxy resin in between and within the fiber tows of a composite, revealing that the modulus exhibits a marked spatial inhomogeneity in proximity of fibers, with a decrease of up to 5% compared to that of bulk epoxy resin in the regions of highest fiber density (see Fig. 1).1 We estimate that it would take a deformation of four times the failure strain to cause such a change in modulus based on residual stresses. Hence, the origin must lie elsewhere. Using the same methodology, we then monitored the elastic properties in situ, during epoxy cure under different thermal and chemical conditions. We find that depending on the reaction rate, the elastic modulus evolves differently as a function of the degree of cure: the faster the rate, the more the modulus lags behind of what would be expected from the amount of cross-links that have formed according to the degree of cure. This is because the overall modulus is based on the stiffness resulting from bonded and non-boned network connections, the latter arising the optimization of network packing that ensues after a slow structural relaxation.2 Provided enough time, the same final modulus is reached, unless network formation is impeded by the under-supply of hardener. To interpret and enhance these results, experiments are complemented with molecular dynamics simulations of the interface. Accordingly, the one-sided confinement of polymer adjacent to a fiber surface results in clearly detectable structural features, e.g., layering and densification, as well as changes in the elastic properties within a spatial extent that reaches significantly beyond the region of distinguishable structural features. In conclusion, we attribute the inhomogeneity in mechanical properties to a combination of hardener depletion and an impediment of structural relaxation due to unilateral confinement that lowers the extent and effectiveness of non-bonded interaction

United States v. Robinson

This article provides an overview of fourth amendment litigation that focused on the question of what constitutes an “unreasonable” search. The Supreme Court had previously provided guidance in Terry v. Ohio and Chimel v. California. This article provides a brief overview of these cases, and then it turns to more thoroughly examine the decision in US v. Robinson