Continued Progress: Promising Evidence on Personalized Learning

The findings are grouped into four sections. The first section on student achievement finds that there were positive effects on student mathematics and reading performance and that the lowest-performing students made substantial gains relative to their peers. The second section on implementation and the perceptions of stakeholders finds that adoption of personalized learning practices varied considerably. Personalized learning practices that are direct extensions of current practice were more common, but implementation of some of the more challenging personalized learning strategies was less common. The third section relates implementation features to outcomes and identifies three elements of personalized learning that were being implemented in tandem in the schools with the largest achievement effects. Finally, the fourth section compares teachers' and students' survey responses to a national sample and finds some differences, such as teachers' greater use of practices that support competency-based learning and greater use of technology for personalization in the schools in this study with implementation data

Subjective assessments of comorbidity correlate with quality of life health outcomes: Initial validation of a comorbidity assessment instrument

BACKGROUND: Interventions to improve care for persons with chronic medical conditions often use quality of life (QOL) outcomes. These outcomes may be affected by coexisting (comorbid) chronic conditions as well as the index condition of interest. A subjective measure of comorbidity that incorporates an assessment of disease severity may be particularly useful for assessing comorbidity for these investigations. METHODS: A survey including a list of 25 common chronic conditions was administered to a population of HMO members age 65 or older. Disease burden (comorbidity) was defined as the number of self-identified comorbid conditions weighted by the degree (from 1 to 5) to which each interfered with their daily activities. We calculated sensitivities and specificities relative to chart review for each condition. We correlated self-reported disease burden, relative to two other well-known comorbidity measures (the Charlson Comorbidity Index and the RxRisk score) and chart review, with our primary and secondary QOL outcomes of interest: general health status, physical functioning, depression screen and self-efficacy. RESULTS: 156 respondents reported an average of 5.9 chronic conditions. Median sensitivity and specificity relative to chart review were 75% and 92% respectively. QOL outcomes correlated most strongly with disease burden, followed by number of conditions by chart review, the Charlson Comorbidity Index and the RxRisk score. CONCLUSION: Self-report appears to provide a reasonable estimate of comorbidity. For certain QOL assessments, self-reported disease burden may provide a more accurate estimate of comorbidity than existing measures that use different methodologies, and that were originally validated against other outcomes. Investigators adjusting for comorbidity in studies using QOL outcomes may wish to consider using subjective comorbidity measures that incorporate disease severity

Predicting declines in physical function in persons with multiple chronic medical conditions: what we can learn from the medical problem list

BACKGROUND: Primary care physicians are caring for increasing numbers of persons with comorbid chronic illness. Longitudinal information on health outcomes associated with specific chronic conditions may be particularly relevant in caring for these populations. Our objective was to assess the effect of certain comorbid conditions on physical well being over time in a population of persons with chronic medical conditions; and to compare these effects to that of hypertension alone. METHODS: We conducted a secondary analysis of 4-year longitudinal data from the Medical Outcomes Study. A heterogeneous population of 1574 patients with either hypertension alone (referent) or one or more of the following conditions: diabetes, coronary artery disease, congestive heart failure, respiratory illness, musculoskeletal conditions and/or depression were recruited from primary and specialty (endocrinology, cardiology or mental health) practices within HMO and fee-for-service settings in three U.S. cities. We measured categorical change (worse vs. same/better) in the SF-36(R) Health Survey physical component summary score (PCS) over 4 years. We used logistic regression analysis to determine significant differences in longitudinal change in PCS between patients with hypertension alone and those with other comorbid conditions and linear regression analysis to assess the contribution of the explanatory variables. RESULTS: Specific diagnoses of CHF, diabetes and/or chronic respiratory disease; or 4 or more chronic conditions, were predictive of a clinically significant decline in PCS. CONCLUSIONS: Clinical recognition of these specific chronic conditions or 4 or more of a list of chronic conditions may provide an opportunity for proactive clinical decision making to maximize physical functioning in these populations

The evolution of GX 339-4 in the low-hard state as seen by NuSTAR and Swift

We analyze eleven NuSTAR and Swift observations of the black hole X-ray binary GX 339-4 in the hard state, six of which were taken during the end of the 2015 outburst, five during a failed outburst in 2013. These observations cover luminosities from 0.5%-5% of the Eddington luminosity. Implementing the most recent version of the reflection model relxillCp, we perform simultaneous spectral fits on both datasets to track the evolution of the properties in the accretion disk including the inner edge radius, the ionization, and temperature of the thermal emission. We also constrain the photon index and electron temperature of the primary source (the "corona"). We find the disk becomes more truncated when the luminosity decreases, and observe a maximum truncation radius of $37R_g$. We also explore a self-consistent model under the framework of coronal Comptonization, and find consistent results regarding the disk truncation in the 2015 data, providing a more physical preferred fit for the 2013 observations.Comment: 15 pages, 8 figures, 6 tables, accepted for publication in The Astrophysical Journa

Component integration strategies in metamorphic 4-junction III-V concentrator solar cells

Progressing beyond 3-junction inverted-metamorphic multijunction solar cells grown on GaAs substrates, to 4-junction devices, requires the development of high quality metamorphic 0.7 eV GaInAs solar cells. Once accomplished, the integration of this subcell into a full, Monolithic, series connected, 4J-IMM structure demands the development of a metamorphic tunnel junction lattice matched to the 1eV GaInAs subcell. Moreover, the 0.7 eV junction adds about 2 hours of growth time to the structure, implying a heavier annealing of the subcells and tunnel junctions grown first. The final 4J structure is above 20 Pm thick, with about half of this thickness used by the metamorphic buffers required to change the lattice constant throughout the structure. Thinning of these buffers would help reduce the total thickness of the 4J structure to decrease its growth cost and the annealing time. These three topics: development of a metamorphic tunnel junction for the 4th junction, analysis of the annealing, and thinning of the structure, are tackled in this work. The results presented show the successful implementation of an antimonide-based tunnel junction for the 4th junction and of pathways to mitigate the impact of annealing and reduce the thickness of the metamorphic buffers

Experimental and modeling analysis of internal luminescence in III-V solar cells

In high quality solar cells, the internal luminescence can be harnessed to enhance the overall performance. Internal confinement of the photons can lead to an increased open-circuit voltage and short-circuit current. Alternatively, in multijunction solar cells the photons can be coupled from a higher bandgap junction to a lower bandgap junction for enhanced performance. We model the solar cell as an optical cavity and compare calculated performance characteristics with measurements. We also describe how very high luminescent coupling alleviates the need for top-cell thinning to achieve current-matching

Metamorphic III-V solar cells: recent progress and potential

Metamorphic semiconductor devices are commonly considered to have inferior electronic quality. However, recent development of compositionally graded buffers and junction structures have led to the achievement of high quality metamorphic solar cells exhibiting internal luminescence efficiencies over 90%. Optimizing the optical design of the solar cell becomes important in order to enhance photon recycling and open circuit voltage in these cells. In this paper we first present recent performance results for 1eV and 0.7eV GaInAs solar cells grown on GaAs substrates. Then an electro-optical model is used to assess the potential performance improvements in current metamorphic solar cells under different realizable design scenarios. The results show that significant improvements can be achieved by improving both the electronic quality and optics of these cells