Race-focused teacher education has centered on changing preservice teachers’ racial beliefs and attitudes. In this article, we build on this work by exploring how preservice teachers identify and ...address issues of race and racism in the everyday work of teaching and learning. To conceptualize these processes, we propose the theoretical framework of “racial noticing,” which extends the literature on teacher noticing to the consideration of racial phenomena. Using a comparative case study design, this study focuses on three elementary preservice teachers (two identifying as White, one identifying as Black) with antiracist inclinations. Findings show that they demonstrated generally strong competencies with racial noticing during a mathematics methods course, but that contextual factors influenced shifts in racial noticing during student teaching. We argue that race-focused teacher education centered on noticing the impact of race and racism in learning settings can make the practice of antiracist teaching more tractable for preservice teachers.
Equity in mathematics classroom discourse is a pressing concern, but analyzing issues of equity using observational tools remains a challenge. In this article, the authors propose
equity analytics as ...a quantitative approach to analyzing aspects of equity and inequity in classrooms. They introduce a classroom observation tool that focuses on relatively
low-inference dimensions of classroom discourse, which are cross-tabulated with demographic markers (e.g., gender, race) to identify patterns of more and less equitable
participation within and across lessons.
When considering a cylindrical, time-encoded imaging system, if the detector is small relative to the mask radius, we can directly apply the analytical models derived for spatial coded aperture to ...cylindrical, time-encoded imaging systems. But when the detector is large relative to the mask radius, the mask pattern observed by the edge of the detector will differ from that of the center, and the system’s imaging performance will deteriorate. This paper derives a large detector model to predict the system response in such cases. Using this model, we vary the design parameters such as detector diameter, mask radius, and mask thickness to assess their impact on angular resolution and contrast-to-noise ratio. Based on those findings, we built a 1-D, dual-particle, cylindrical, time-encoded imaging system to use in nuclear non-proliferation applications. Reconstructed images of a Cf-252 point source have a full width at half maximum of 7.7° for both gamma-ray and fast neutron signals when using maximum likelihood expectation maximization. We experimentally verify the large detector model and quantitatively show when the small detector assumption breaks down.
Improving equity in undergraduate STEM is a national imperative. Although there is a rapidly growing body of research in this area, there is still a need to generate empirical evidence for equitable ...teaching techniques. We ground our work in Complex Instruction, an extensively researched pedagogical approach based on sociological theories and the malleability of status. This approach has been applied primarily in K-12 classrooms. In this manuscript, we explore the application of one strategy from Complex Instruction-assigning competence-to undergraduate STEM classrooms. We provide an analysis of three instructors' implementation of assigning competence and track the impact on student participation. This work makes a unique contribution to the field, as the first study that directly documents changes in student participation resulting from assigning competence in undergraduate STEM.
Background/Context: There is evidence that race affects students' learning experiences in mathematics, a subject typically thought of as "race-neutral" and "culture-free." Research in psychology and ...sociology has shown that racial narratives (e.g., "Asians are good at math") are pervasive in U.S. culture and play a critical role in shaping people's lived experiences. However, racial narratives have received little explicit attention in the mathematics education literature. Purpose: The purpose of this study was to examine the racial ideological context of mathematics education, specifically in terms of how students made sense of racial narratives about academic ability. Participants: Thirty-five students identifying as Asian, Black or African American, Latinx, Polynesian, White, and mixed race were interviewed. These students were recruited from four mathematics classrooms observed by the author at a racially diverse high school in Northern California. Research Design: This qualitative study employed an ethnographic research design to gather data on the meanings students constructed around issues of race in the context of mathematics. Data Collection and Analysis: A semi-structured interview protocol was used to conduct individual interviews with each student participant. Field notes were taken during 130 hours of participant observation over the course of a school year. Interview transcripts and field notes were analyzed for instances in which participants invoked racial narratives. Each of these narratives was first coded by topic and by the racial group to which the narrative referred. Narrative clusters were then identified and analyzed in order to understand how the narratives were related to each other. Findings: Students invoked a variety of racial narratives about both mathematical and nonmathematical topics (e.g., athletic ability, general intelligence, parenting practices). Importantly, students did not invoke these narratives in isolation. Instead, nearly all of these narratives were invoked in conjunction with at least one other narrative. This relationality among racial narratives shows how the academic abilities of learners from diverse racial backgrounds are constructed in relation to each other, often in ways that position non-Asian students of color as inferior in mathematics. Conclusions/Recommendations: This article suggests the need for study designs and analytical approaches that theorize race as a relational construct that transcends the Black-White paradigm. Further, this article challenges researchers and practitioners to reconsider boundaries between what is deemed "mathematical" and "nonmathematical" in classroom discourse, specifically with respect to sociopolitical phenomena like race.
In this conceptual article, Niral Shah critically analyzes how the narrative that "Asians are good at math" positions Asian people as racial subjects. Despite being false, the "Asians are good at ...math" narrative is prominent in STEM education and is also familiar to the general public. To analyze the narrative's discursive impact on Asian personhood, Shah uses poststructural race theory and Mills's notion of the racial contract, focusing on the interaction between discourses of STEM and discourses of race. Rather than a harmless compliment, Shah argues that the type of mathematical success implied in the narrative dehumanizes Asian people and perpetuates White supremacy, and calls for racial equity and justice work in STEM education to account for ontological questions of personhood alongside traditional concerns about academic content learning and economic access to STEM careers.
In hyperpolarized xenon magnetic resonance imaging (HP (129)Xe MRI), the inhaled spin-1/2 isotope of xenon gas is used to generate the MR signal. Because hyperpolarized xenon is an MR signal source ...with properties very different from those generated from water-protons, HP (129)Xe MRI may yield structural and functional information not detectable by conventional proton-based MRI methods. Here we demonstrate the differential distribution of HP (129)Xe in the cerebral cortex of the rat following a pain stimulus evoked in the animal's forepaw. Areas of higher HP (129)Xe signal corresponded to those areas previously demonstrated by conventional functional MRI (fMRI) methods as being activated by a forepaw pain stimulus. The percent increase in HP (129)Xe signal over baseline was 13-28%, and was detectable with a single set of pre and post stimulus images. Recent innovations in the production of highly polarized (129)Xe should make feasible the emergence of HP (129)Xe MRI as a viable adjunct method to conventional MRI for the study of brain function and disease.
To describe the details and experience of implementing a MR-only workflow in the clinic for simulation and planning of prostate cancer patients.
Forty-eight prostate cancer patients from June 2016 - ...Dec 2016 receiving external beam radiotherapy were scheduled to undergo MR-only simulation. MR images were acquired for contouring (T2w axial, coronal, sagittal), synthetic-CT generation (3D FFE-based) and fiducial identification (3D bFFE-based). The total acquisition time was 25 min. Syn-CT was generated at the console using commercial software called MRCAT. As part of acceptance testing of the MRCAT package, external laser positioning system QA (< 2 mm) and geometric fidelity QA (< 2 mm within 50 cm LR and 30 cm AP) were performed and baseline values were set. Our current combined CT + MR simulation process was modified to accommodate a MRCAT-based MR-only simulation workflow. An automated step-by-step process using a MIM™ workflow was created for contouring on the MR images. Patient setup for treatment was achieved by matching the MRCAT DRRs with the orthogonal KV radiographs based on either fiducial ROIs or bones. 3-D CBCTs were acquired and compared with the MR/syn-CT to assess the rectum and bladder filling compared to simulation conditions.
Forty-two patients successfully underwent MR-only simulation and met all of our institutional dosimetric objectives that were developed based on a CT + MR-based workflow. The remaining six patients either had a hip prosthesis or their large body size fell outside of the geometric fidelity QA criteria and thus they were not candidates for MR-only simulation. A total time saving of ~15 min was achieved with MR-based simulation as compared to CT + MR-based simulation. An automated and organized MIM workflow made contouring on MR much easier, quicker and more accurate compared with combined CT + MR images because the temporal variations in normal structure was minimal. 2D and 3D treatment setup localization based on bones/fiducials using a MRCAT reference image was successfully achieved for all cases.
MR-only simulation and planning with equivalent or superior target delineation, planning and treatment setup localization accuracy is feasible in a clinical setting. Future work will focus on implementing a robust 3D isotropic acquisition for contouring.
To the first order, the localization precision and angular resolution of a cylindrical, time-encoded imaging (c-TEI) system is governed by the geometry of the system. Improving either measure ...requires increasing the mask radius or decreasing the detector diameter, both of which are undesirable. We propose an alternative option of repositioning the detector within the mask to increase the detector-to-mask distance in the direction of a source, thereby improving the localization precision and angular resolution in that direction. Since the detector-to-mask distance only increases for a small portion of the field of view (FOV), we propose implementing adaptive imaging where one leverages data collected during the measurement to optimize the system configuration. This article utilizes both simulations and experiments to set upper bounds on the potential gain from adaptive detector movements for one and two sources in the FOV. When only one source is present, adaptive detector movements can improve the localization precision and angular resolution by 20% for a source at 90 cm and by 32% for a far-field source. When two sources are present, adaptive detector movements can improve localization precision and angular resolution by up to 50% for sources that are ~10° apart (90 cm from the system). We experimentally verify these results through maximum likelihood estimation of the source position(s) and image reconstruction of point sources that are close together. As a demonstration of an adaptive imaging algorithm, we image a complex arrangement of special nuclear material at the Zero Power Physics Reactor facility at Idaho National Laboratory.
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