Negotiation in classroom conversations: An examination of teacher and student engagement

Ph.D

Assessment of a statistical AIF extraction method for dynamic PET studies with 15O water and 18F fluorodeoxyglucose in locally advanced breast cancer patients

Blood flow-metabolism mismatch from dynamic positron emission tomography (PET) studies with O-15-labeled water (H2O) and F-18-labeled fluorodeoxyglucose (FDG) has been shown to be a promising diagnostic for locally advanced breast cancer (LABCa) patients. The mismatch measurement involves kinetic analysis with the arterial blood time course (AIF) as an input function. We evaluate the use of a statistical method for AIF extraction (SAIF) in these studies. Fifty three LABCa patients had dynamic PET studies with H2O and FDG. For each PET study, two AIFs were recovered, an SAIF extraction and also a manual extraction based on a region of interest placed over the left ventricle (LV-ROI). Blood flow-metabolism mismatch was obtained with each AIF, and kinetic and prognostic reliability comparisons were made. Strong correlations were found between kinetic assessments produced by both AIFs. SAIF AIFs retained the full prognostic value, for pathologic response and overall survival, of LV-ROI AIFs. (c) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI

Impact of PET/CT system, reconstruction protocol, data analysis method, and repositioning on PET/CT precision:An experimental evaluation using an oncology and brain phantom

Purpose: In longitudinal oncological and brain PET/CT studies, it is important to understand the repeatability of quantitative PET metrics in order to assess change in tracer uptake. The present studies were performed in order to assess precision as function of PET/CT system, reconstruction protocol, analysis method, scan duration (or image noise), and repositioning in the field of view. Methods: Multiple (repeated) scans have been performed using a NEMA image quality (IQ) phantom and a 3D Hoffman brain phantom filled with F-18 solutions on two systems. Studies were performed with and without randomly (<2 cm) repositioning the phantom and all scans (12 replicates for IQ phantom and 10 replicates for Hoffman brain phantom) were performed at equal count statistics. For the NEMA IQ phantom, we studied the recovery coefficients (RC) of the maximum (SUVmax), peak (SUVpeak), and mean (SUVmean) uptake in each sphere as a function of experimental conditions (noise level, reconstruction settings, and phantom repositioning). For the 3D Hoffman phantom, the mean activity concentration was determined within several volumes of interest and activity recovery and its precision was studied as function of experimental conditions. Results: The impact of phantom repositioning on RC precision was mainly seen on the Philips Ingenuity PET/CT, especially in the case of smaller spheres (<17 mm diameter, P <0.05). This effect was much smaller for the Siemens Biograph system. When exploring SUVmax, SUVpeak, or SUVmean of the spheres in the NEMA IQ phantom, it was observed that precision depended on phantom repositioning, reconstruction algorithm, and scan duration, with SUVmax being most and SUVpeak least sensitive to phantom repositioning. For the brain phantom, regional averaged SUVs were only minimally affected by phantom repositioning (<2 cm). Conclusion: The precision of quantitative PET metrics depends on the combination of reconstruction protocol, data analysis methods and scan duration (scan statistics). Moreover, precision was also affected by phantom repositioning but its impact depended on the data analysis method in combination with the reconstructed voxel size (tissue fraction effect). This study suggests that for oncological PET studies the use of SUVpeak may be preferred over SUVmax because SUVpeak is less sensitive to patient repositioning/tumor sampling. (c) 2017 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine

All Our Voices : Developing Critical Literacy and Exploring Identity in a Secondary English Classroom

AOV focuses on building critical literacy skills by using two kinds of writing: narrative reflections and academic criticisms. The writing encourages students to critically analyze their own experiences, and then contextualize those experiences among a greater sociopolitical context. Students read "Their Eyes Were Watching God," a novel about an African-American woman on a search for happiness, and supplementary non-fiction texts in order to define and analyze their own identities, although any number of texts could have been used. When students were discussing and writing about themselves, they wrote for an audience of their peers, and when students were discussing and writing about others' identities, they wrote for a community of academics. This ability to switch registers for specific contexts is a necessary skill in the English classroom. The curriculum culminated in a project in which students created a video exploring their multiple identities. Participating students generally mastered only one register--formal or informal--and approximately half were able to critically analyze their own identities and experiences. However, almost all students complicated their concept of academic identity, defining a scholar as someone who questions and seeks answers rather than someone who merely succeeds in school. Student progress in the academic register after the implementation of the curriculum suggests this changed self-concept could be a precursor to academic achievemen

Oregon\u27s Public Trust Doctrine: Public Rights in Waters, Wildlife, and Beaches

Oregon’s public trust doctrine has been misunderstood. The doctrine has not been judicially interpreted in over thirty years but was the subject of an Oregon Attorney General’s opinion in 2005. That opinion interpreted the scope of the doctrine to be limited to the beds of tidelands and navigable-for-title waters and erected a separate “public use” doctrine protecting public rights in other waters, including recreational waters. However, since Oregon courts have never limited public rights in the state’s waters to those with publicly owned bedlands, the opinion should have recognized that the public trust doctrine provides broad public recreational rights in all waters. Indeed, since early statehood, Oregon courts and the legislature have recognized that water is publicly owned, and the Oregon Supreme Court has ruled consistently in favor of public rights in waterways, based on language in the Statehood Act that declared navigable waters to be public highways that would remain “forever free,” not monopolized by private owners. Moreover, in the early 20th century, the court explicitly ruled that the scope of public rights in publicly-owned waters could and should evolve over time. This Article maintains that the Oregon public trust doctrine is grounded on public ownership of natural resources held in trust by the state in a sovereign capacity. The state has always claimed ownership of water and wildlife within the state, so the courts should recognize both as public trust resources. Although the state can authorize private rights in those resources, all private rights are subject to the state’s sovereign ownership – a public easement – requiring the state to maintain these resources as trustee for the public. Like the Statehood Act’s declaration of public ownership of waterways, courts should interpret the public trust doctrine to be implicit in other statutory declarations of public ownership of natural resources. Similarly, use rights in ocean beaches, claimed by the public under the doctrine of custom, are public trust resources, necessary to enable public use of the adjacent ocean waters. This Article suggests that public ancillary rights exist in other uplands where necessary to provide public access to, or preservation of, public trust water and wildlife resources. sovereign owner of water, wildlife, and ancillary uplands. In an era of widespread skepticism of government management, the venerable public trust doctrine seems an especially appropriate mechanism to give citizens an opportunity to gain review of government action and inaction threatening unsustainable development of natural resources that are central to the state’s identity, culture, and economy