Automated Essay Evaluation (AEE) systems are being increasingly adopted in the United States to support writing instruction. AEE systems are expected to assist teachers in providing increased ...higher-level feedback and expediting the feedback process, while supporting gains in students’ writing motivation and writing quality. The current study explored these claims using a quasi-experimental study. Four eighth-grade English Language Arts (ELA) classes were assigned to a combined feedback condition in which they received feedback on their writing from their teacher and from an automated essay evaluation (AEE) system called PEG Writing®. Four other eighth-grade ELA classes were assigned to a teacher feedback-only condition, in which they received feedback from their teacher via GoogleDocs. Results indicated that teachers gave the same median amount feedback to students in both condition, but gave proportionately more feedback on higher-level writing skills to students in the combined PEG + Teacher Feedback condition. Teachers also agreed that PEG assisted them in saving one-third to half the time it took to provide feedback when they were the sole source of feedback (i.e., the GoogleDocs condition). At the conclusion of the study, students in the combined feedback condition demonstrated increases in writing persistence, though there were no differences between groups with regard to final-draft writing quality.
•We compare the effects of combining teacher feedback with automated feedback.•Teachers using automated feedback gave proportionately more higher-level feedback.•The combined feedback condition was associated with greater student persistence.•Automated feedback helped save time and effort without sacrificing writing quality.•Combining automated teacher and automated feedback benefits teachers and students.
Observation of dynamical fermionization Wilson, Joshua M; Malvania, Neel; Le, Yuan ...
Science (American Association for the Advancement of Science),
03/2020, Letnik:
367, Številka:
6485
Journal Article
Recenzirano
Odprti dostop
The wave function of a Tonks-Girardeau (T-G) gas of strongly interacting bosons in one dimension maps onto the absolute value of the wave function of a noninteracting Fermi gas. Although this ...fermionization makes many aspects of the two gases identical, their equilibrium momentum distributions are quite different. We observed dynamical fermionization, where the momentum distribution of a T-G gas evolves from bosonic to fermionic after its axial confinement is removed. The asymptotic momentum distribution after expansion in one dimension is the distribution of rapidities, which are the conserved quantities associated with many-body integrable systems. Our measurements agree well with T-G gas theory. We also studied momentum evolution after the trap depth is suddenly changed to a new nonzero value, and we observed the theoretically predicted bosonic-fermionic oscillations.
There is growing interest in using PET/CT for evaluating early response to therapy in cancer treatment. Although widely available and convenient to use, standardized uptake value (SUV) measurements ...can be influenced by a variety of biologic and technologic factors. Many of these factors can be addressed with close attention to detail and appropriate quality control. This article will review factors potentially affecting SUV measurements and provide recommendations on ways to minimize when using serial PET to assess early response to therapy.
Scanner and reconstruction parameters can significantly affect SUV measurements. When using serial SUV measurements to assess early response to therapy, imaging should be performed on the same scanner using the same image acquisition and reconstruction protocols. In addition, attention to detail is required for accurate determination of the administered radiopharmaceutical dose.
Abstract
Drone use has increased in the last decade prompting management efforts to regulate flights near vulnerable wildlife; however, these efforts are hindered by a lack of data characterising ...drone‐induced wildlife disturbance. Many shorebird populations are rapidly declining and efforts to survey them can be hampered by the inaccessibility of their habitat. Drone surveys might overcome this barrier, although there is a risk that increased drone use near shorebirds may cause disturbance and exacerbate declines. We characterise drone‐induced disturbance for mixed‐species shorebird flocks to inform the management of drones near shorebirds.
We conducted 240 drone approaches of mixed‐species flocks containing roosting non‐breeding shorebirds in Moreton Bay, eastern Australia. We performed approaches horizontally at varying vertical distances and recorded metrics characterising the drone, flock and environment. This enabled us to estimate the factors influencing disturbance as well as the distance of an approaching drone at which the flock is likely to take flight.
We determined the drone‐induced flight initiation distance for 12 species of waterbird, including seven shorebird species. We could not approach Eastern Curlew
Numenius madagascariensis
at any vertical distance below the recreational drone limit of 120 m without inducing flight; however, for all other species, there was less than 20% probability that they would take flight when approached by a drone at vertical distances above 60 m. We do not recommend approaches below 30 m. We also found that flight initiation of mixed‐species flocks is largely dictated by the most sensitive species present, and that disturbance generally increases with approach velocity, drone noise/size, decreasing distance, and if the drone is obscured by trees.
Policy Implications.
We conclude that (i) drone use needs to be carefully regulated to ensure roosting shorebird flocks are not approached within distances that will disturb the most sensitive species likely to be present, (ii) researchers contemplating drone surveys need to carefully evaluate the risk of disturbance, especially where there are mixed‐species flocks, and (iii) that alternatives to drone surveys should be sought wherever disturbance data for the species potentially encountered are unavailable.
Resumen
El uso de drones ha aumentado en la última década, lo que ha promovido esfuerzos para su gestión con el fin de regular su uso cerca de fauna vulnerable; sin embargo, estos esfuerzos son limitados por la falta de datos que caractericen el nivel de perturbación de la fauna inducida por drones. Muchas poblaciones de aves playeras están disminuyendo rápidamente y la inaccesibilidad de su hábitat puede dificultar los estudios sobre ellas. Los estudios con drones podrían ayudar superar este obstáculo, aunque existe el riesgo de que el aumento del uso de drones cerca de las aves playeras cause molestias y agrave el declive de las mismas. Caracterizamos las perturbaciones de las aves playeras inducidas por drones en bandadas de especies de aves mixtas para informar a la gestión de drones cerca de las aves playeras.
Realizamos 240 acercamientos de drones a bandadas de especies de aves playeras mixtas en estado no reproductivo en un sitio de descanso en la Bahía de Moreton, al este de Australia. Realizamos acercamientos horizontales a varias distancias verticales y registramos las métricas que caracterizaban al dron, la bandada y el entorno. Esto nos permitió estimar los factores que influyen a la perturbación de aves playeras, así como la distancia del acercamiento de dron a la que es probable que la bandada emprenda el vuelo.
Determinamos la distancia de iniciación del vuelo inducida por drones para 12 especies de aves acuáticas, incluyendo 7 especies de aves playeras. No pudimos acercarnos al Zarapito de Siberia (Numenius madagascariensis) a ninguna distancia vertical que este por debajo del límite de vuelo recreativo para drones que es de 120 m sin inducir el vuelo del ave, sin embargo para todas las demás especies había menos de un 20% de probabilidad de que emprendieran el vuelo cuando el dron se les acercaba a distancias verticales superiores a 60 m. No recomendamos acercamientos por debajo de 30 m. También encontramos que el inicio del vuelo de bandadas de especies mixtas viene dictado en gran medida por la especie presente que es más sensible a perturbaciones y la perturbación generalmente aumenta con la velocidad de acercamiento del dron, la disminución de la distancia entre el dron y el ave, el ruido/tamaño del dron, y si el dron está tapado por los árboles.
Implicaciones para políticas
. Concluimos que (i) el uso de drones debe regularse cuidadosamente para garantizar que los mismos no se acerquen a las bandadas de aves playeras en sitios de descanso a distancias que puedan molestar a las especies más sensibles que probablemente estén presentes, (ii) los investigadores que contemplen realizar estudios con drones deben evaluar cuidadosamente el riesgo de perturbación, especialmente cuando haya bandadas de especies mixtas, y (iii) que deben buscarse alternativas a los estudios con drones cuando no se disponga de datos de perturbación para las especies potencialmente encontradas.
Purpose
Phantoms are useful tools in diagnostic CT, but practical limitations reduce phantoms to being only a limited patient surrogate. Furthermore, a phantom with a single cross sectional area ...cannot be used to evaluate scanner performance in modern CT scanners that use dose reduction techniques such as automated tube current modulation (ATCM) and iterative reconstruction (IR) algorithms to adapt x‐ray flux to patient size, reduce radiation dose, and achieve uniform image noise. A new multisized phantom (Mercury Phantom, MP) has been introduced, representing multiple diameters. This work aimed to ascertain if measurements from MP can predict radiation dose and image noise in clinical CT images to prospectively inform protocol design.
Methods
The adult MP design included four different physical diameters (18.5, 23.0, 30.0, and 37.0 cm) representing a range of patient sizes. The study included 1457 examinations performed on two scanner models from two vendors, and two clinical protocols (abdominopelvic with and chest without contrast). Attenuating diameter, radiation dose, and noise magnitude (average pixel standard deviation in uniform image) was automatically estimated in patients and in the MP using a previously validated algorithm. An exponential fit of CTDIvol and noise as a function of size was applied to patients and MP data. Lastly, the fit equations from the phantom data were used to fit the patient data. In each patient distribution fit, the normalized root mean square error (nRMSE) values were calculated in the residuals’ plots as a metric to indicate how well the phantom data can predict dose and noise in clinical operations as a function of size.
Results
For dose across patient size distributions, the difference between nRMSE from patient fit and MP model data prediction ranged between 0.6% and 2.0% (mean 1.2%). For noise across patient size distributions, the nRMSE difference ranged between 0.1% and 4.7% (mean 1.4%).
Conclusions
The Mercury Phantom provided a close prediction of radiation dose and image noise in clinical patient images. By assessing dose and image quality in a phantom with multiple sizes, protocol parameters can be designed and optimized per patient size in a highly constrained setup to predict clinical scanner and ATCM system performance.
Extremely high-gain source-gated transistors Zhang, Jiawei; Wilson, Joshua; Auton, Gregory ...
Proceedings of the National Academy of Sciences,
03/2019, Letnik:
116, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Despite being a fundamental electronic component for over 70 years, it is still possible to develop different transistor designs, including the addition of a diode-like Schottky source electrode to ...thin-film transistors. The discovery of a dependence of the source barrier height on the semiconductor thickness and derivation of an analytical theory allow us to propose a design rule to achieve extremely high voltage gain, one of the most important figures of merit for a transistor. Using an oxide semiconductor, an intrinsic gain of 29,000 was obtained, which is orders of magnitude higher than a conventional Si transistor. These same devices demonstrate almost total immunity to negative bias illumination temperature stress, the foremost bottleneck to using oxide semiconductors in major applications, such as display drivers. Furthermore, devices fabricated with channel lengths down to 360 nm display no obvious short-channel effects, another critical factor for high-density integrated circuits and display applications. Finally, although the channel material of conventional transistors must be a semiconductor, by demonstrating a high-performance transistor with a semimetal-like indium tin oxide channel, the range and versatility of materials have been significantly broadened.
Abstract
Abortion’s centrality to the Christian Right, together with that movement’s importance to Republican Party politics, as well as the policy realities of abortion, have all combined to make ...regulating abortion a fixture within U.S. state politics for decades. While the levels and forms of state activity have varied since the 1980s, the Trump presidency has produced strategic changes in the content and perceived importance of abortion policy. Notably, recent changes in the state politics of abortion have not just been on the side of Republican states restricting abortion access, the most traditional and highest profile form of policy activity in this area, but have also taken the form of Democratic states actively defending abortion access. This article provides an overview of the interrelated changes in party politics, perceptions of political opportunities, and the content of state abortion regulations. It concludes that the frequency of state abortion laws has increased modestly during the Trump presidency, but substantive shifts in recent policies create the potential to fundamentally reorganize state and national abortion politics.
Purpose:
This work involved the development of a phantom-based method to quantify the performance of tube current modulation and iterative reconstruction in modern computed tomography (CT) systems. ...The quantification included resolution, HU accuracy, noise, and noise texture accounting for the impact of contrast, prescribed dose, reconstruction algorithm, and body size.
Methods:
A 42-cm-long, 22.5-kg polyethylene phantom was designed to model four body sizes. Each size was represented by a uniform section, for the measurement of the noise-power spectrum (NPS), and a feature section containing various rods, for the measurement of HU and the task-based modulation transfer function (TTF). The phantom was scanned on a clinical CT system (GE, 750HD) using a range of tube current modulation settings (NI levels) and reconstruction methods (FBP and ASIR30). An image quality analysis program was developed to process the phantom data to calculate the targeted image quality metrics as a function of contrast, prescribed dose, and body size.
Results:
The phantom fabrication closely followed the design specifications. In terms of tube current modulation, the tube current and resulting image noise varied as a function of phantom size as expected based on the manufacturer specification: From the 16- to 37-cm section, the HU contrast for each rod was inversely related to phantom size, and noise was relatively constant (<5% change). With iterative reconstruction, the TTF exhibited a contrast dependency with better performance for higher contrast objects. At low noise levels, TTFs of iterative reconstruction were better than those of FBP, but at higher noise, that superiority was not maintained at all contrast levels. Relative to FBP, the NPS of iterative reconstruction exhibited an ∼30% decrease in magnitude and a 0.1 mm−1 shift in the peak frequency.
Conclusions:
Phantom and image quality analysis software were created for assessing CT image quality over a range of contrasts, doses, and body sizes. The testing platform enabled robust NPS, TTF, HU, and pixel noise measurements as a function of body size capable of characterizing the performance of reconstruction algorithms and tube current modulation techniques.
The 2014 Supreme Court ruling on McCullen v. Coakley striking down a Massachusetts law regulating anti-abortion activism marked the reengagement of the Supreme Court in abortion politics. A throwback ...to the days of clinic- front protests, the decision seemed a means to reinvigorate the old street politics of abortion. The Court's ruling also highlights the success of a decades' long effort by anti-abortion activists to transform the very politics of abortion. The New States of Abortion Politics, written by leading scholar Joshua C. Wilson, tells the story of this movement, from streets to legislative halls to courtrooms. With the end of clinic-front activism, lawyers and politicians took on the fight. Anti-abortion activists moved away from a doomed frontal assault on Roe v. Wade and adopted an incremental strategy—putting anti-abortion causes on the offensive in friendly state forums and placing reproductive rights advocates on the defense in the courts. The Supreme Court ruling on Whole Woman's Health v. Hellerstedt in 2016 makes the stakes for abortion politics higher than ever. This book elucidates how—and why.
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