321 research outputs found
Together We Rise: Reaching Inclusivity for Student Excellence
This presentation outlines the BIONIC (Believe It Or Not I Care) Program at Mattoon High School. For the past 10 years, Dr. Larson and a team of counseling interns have partnered with Mattoon High School to implement BIONIC (Believe It Or Not I Care), a school-wide peer mentoring program
Réalisation d’un laser à faible courant de seuil, avec des boites quantiques InAs/InP organisées et couplées latéralement
Nous présentons ici la réalisation d’un laser à faible courant de seuil avec des boites quantiques (QDs) organisées et couplées InAs/InP sur subsstrat (311)B pour une émission à 1.55 m. En effet, pour des hautes densités de QDs, une organisation périodique apparaît dans le plan. Cette organisation renforce le couplage latéral inter-boites. Des expériences de magnéto-photoluminescence permettent de mettre en évidence ces effets de couplage. Ce couplage améliore l’injection des porteurs. Une émission laser avec des faibles courants de seuil est obtenue avec de telles boites
Enhanced light extraction from InGaN/GaN quantum wells with silver gratings
We demonstrate that an extraction enhancement by a factor of 2.8 can be obtained for a GaN quantum well structure using metallic nanostructures, compared to a flat semiconductor. The InGaN/GaN quantum well is inserted into a dielectric waveguide, naturally formed in the structure, and a silver grating is deposited on the surface and covered with a polymer film. The polymer layer greatly improves the extraction compared to a single metallic grating. The comparison of the experiments with simulations gives strong indications on the key role of weakly guided modes in the polymer layer diffracted by the grating.Peer reviewe
Automated quantification of steatosis: agreement with stereological point counting
Background: Steatosis is routinely assessed histologically in clinical practice and research. Automated image analysis can reduce the effort of quantifying steatosis. Since reproducibility is essential for practical use, we have evaluated different analysis methods in terms of their agreement with stereological point counting (SPC) performed by a hepatologist. Methods: The evaluation was based on a large and representative data set of 970 histological images from human patients with different liver diseases. Three of the evaluated methods were built on previously published approaches. One method incorporated a new approach to improve the robustness to image variability. Results: The new method showed the strongest agreement with the expert. At 20Ă— resolution, it reproduced steatosis area fractions with a mean absolute error of 0.011 for absent or mild steatosis and 0.036 for moderate or severe steatosis. At 10Ă— resolution, it was more accurate than and twice as fast as all other methods at 20Ă— resolution. When compared with SPC performed by two additional human observers, its error was substantially lower than one and only slightly above the other observer. Conclusions: The results suggest that the new method can be a suitable automated replacement for SPC. Before further improvements can be verified, it is necessary to thoroughly assess the variability of SPC between human observers
Wet scavenging of soluble gases in DC3 deep convective storms using WRF-Chem simulations and aircraft observations
We examine wet scavenging of soluble trace gases in storms observed during the Deep Convective Clouds and Chemistry (DC3) field campaign. We conduct high-resolution simulations with the Weather Research and Forecasting model with Chemistry (WRF-Chem) of a severe storm in Oklahoma. The model represents well the storm location, size, and structure as compared with Next Generation Weather Radar reflectivity, and simulated CO transport is consistent with aircraft observations. Scavenging efficiencies (SEs) between inflow and outflow of soluble species are calculated from aircraft measurements and model simulations. Using a simple wet scavenging scheme, we simulate the SE of each soluble species within the error bars of the observations. The simulated SEs of all species except nitric acid (HNO_3) are highly sensitive to the values specified for the fractions retained in ice when cloud water freezes. To reproduce the observations, we must assume zero ice retention for formaldehyde (CH_2O) and hydrogen peroxide (H_2O_2) and complete retention for methyl hydrogen peroxide (CH_3OOH) and sulfur dioxide (SO_2), likely to compensate for the lack of aqueous chemistry in the model. We then compare scavenging efficiencies among storms that formed in Alabama and northeast Colorado and the Oklahoma storm. Significant differences in SEs are seen among storms and species. More scavenging of HNO_3 and less removal of CH_3OOH are seen in storms with higher maximum flash rates, an indication of more graupel mass. Graupel is associated with mixed-phase scavenging and lightning production of nitrogen oxides (NO_x), processes that may explain the observed differences in HNO_3 and CH_3OOH scavenging
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