Shroom2 regulates endothelial morphogenesis and centrosome duplication through the specific sub-cellular recruitment of Rho-kinase.

The ability of epithelial cells to change shape is essential to the patterning of tissues and organs during development of the vertebrate embryo. Epithelial morphogenesis is mediated by the molecular regulation of cytoskeletal dynamics which underlies cellular adhesion, motility, polarity, and proliferation. The Shroom family of proteins regulates epithelial morphogenesis by promoting MyosinII-dependent changes in epithelial morphology through the ability to bind both F-actin and Rho kinase (Rock). Shroom3 is necessary to induce apical constriction of the neural epithelium and is required for proper neural tube closure during development. However, the roles of other family members are unknown. This work seeks to determine the role and mechanism of action for Shroom2 in epithelial cell biology. Through RNAi, the loss of Shroom2 reduces contractility of endothelial cells. Shroom2 physically interacts with Rock and is necessary for its cortical localization. By impeding Rock localization and reducing contractility, Shroom2 knockdown alters cytoskeletal organization, adhesion, and motility which ultimately affects in vitro angiogenesis. During these studies, it also became clear that Shroom2 localizes to the centrosome where it is required to maintain efficient centrosome duplication in a Rock-dependent manner. The results described here expand a role for the Shroom proteins in the sub-cellular localization of Rock which mediates a subset of Rock functions within epithelial cells

Essays on the economics of education of underserved populations

This dissertation examines how current targeted accountability and funding provisions under federal guidelines impact the academic outcomes of the country's more underserved populations.The first chapter demonstrates that accountability at the race level leads to increased reading and math achievement for students. I investigate the impact of school-level accountability on racial subgroups within a school, using a regression-discontinuity design with student-level Texas panel data on third through eighth graders from 2004 through 2011. The targeted incentives increase passing rates by 1-2 percentage points and the scores by .03 standard deviations in both math and reading. These results persist for two to three years after intervention, but fade out by the fourth year. Furthermore, students outside the targeted group are not hindered, with no effect on passing rates and scores. A deeper analysis suggests that schools are not focusing on high-leverage students but rather implementing wide-ranging interventions. I also find that the majority of gains are due to gains among Black students, though it is not clear whether this is due to racial targeting. In the second chapter, I analyze the impact of federally designed and funded interventions on student achievement, both of targeted students and non-targeted students. Under the No Child Left Behind (NCLB) act of 2001, schools with less than 40% low-income students use federal Title I funds for a Targeted Assistance Program, where schools above 40% are free to use those same funds as general school money. This paper uses a fuzzy regression discontinuity design around the 40% threshold with student-level Texas panel data on third through eighth graders from 2004 through 2011 to investigate. The evidence suggests that there is no difference in student outcomes, on the whole or among subsamples, between the methods of using the federal funding. The third chapter of my dissertation shows that the impact of Title I funding on student achievement is complex, benefiting certain subgroups of students while impacting others negatively. I use an instrumental variable research design in order to estimate impacts while keeping external validity through exploiting the large data set available, which includes student-level panel data on Texas public school students from the years 2004 through 2011. Title I funding increases math passing rates by 3 percentage points and has no impact on neither reading passing rates nor standardized scores for either subject. Elementary school students are impacted negatively by Title I funding in both math and reading, while lower-performing and low-income middle school students show large, though insignificant, effects of the funding on both math and reading exams. Unfortunately, this study cannot speak to the impacts on high school students.Economic

Teachers’ Self-Reported Pedagogical Changes: Are We Preparing Teachers for Online STEM Education?

At the onset of the COVID-19 pandemic in March 2020, K-5 teachers were forced to shift their teaching practices from in-person instruction to an emergency remote teaching (ERT) format. Using the TPACK framework (Koehler et al., 2014), this study explores how teachers’ pedagogical practices for STEM instruction may have changed during and after ERT. The results indicate no significant differences in terms of direct instruction. Still, there were noticeable changes with collaborative learning and teachers’ use of technological tools in STEM classrooms. Teachers’ self-reporting of their pedagogical practices shift highlights the need for further professional development in the practical use of technological tools to meet current needs

Determining the need for nursing home beds

Thesis. 1975. M.C.P.--Massachusetts Institute of Technology. Dept. of Urban Studies and Planning.Includes bibliographical references.by Matthew E. Farber.M.C.P

Accessibility to health care facilities in Montreal Island: an application of relative accessibility indicators from the perspective of senior and non-senior residents

<p>Abstract</p> <p>Background</p> <p>Geographical access to health care facilities is known to influence health services usage. As societies age, accessibility to health care becomes an increasingly acute public health concern. It is known that seniors tend to have lower mobility levels, and it is possible that this may negatively affect their ability to reach facilities and services. Therefore, it becomes important to examine the mobility situation of seniors vis-a-vis the spatial distribution of health care facilities, to identify areas where accessibility is low and interventions may be required.</p> <p>Methods</p> <p>Accessibility is implemented using a cumulative opportunities measure. Instead of assuming a fixed bandwidth (i.e. a distance threshold) for measuring accessibility, in this paper the bandwidth is defined using model-based estimates of average trip length. Average trip length is an all-purpose indicator of individual mobility and geographical reach. Adoption of a spatial modelling approach allows us to tailor these estimates of travel behaviour to specific locations and person profiles. Replacing a fixed bandwidth with these estimates permits us to calculate customized location- and person-based accessibility measures that allow inter-personal as well as geographical comparisons.</p> <p>Data</p> <p>The case study is Montreal Island. Geo-coded travel behaviour data, specifically average trip length, and relevant traveller's attributes are obtained from the Montreal Household Travel Survey. These data are complemented with information from the Census. Health care facilities, also geo-coded, are extracted from a comprehensive business point database. Health care facilities are selected based on Standard Industrial Classification codes 8011-21 (Medical Doctors and Dentists).</p> <p>Results</p> <p>Model-based estimates of average trip length show that travel behaviour varies widely across space. With the exception of seniors in the downtown area, older residents of Montreal Island tend to be significantly less mobile than people of other age cohorts. The combination of average trip length estimates with the spatial distribution of health care facilities indicates that despite being more mobile, suburban residents tend to have lower levels of accessibility compared to central city residents. The effect is more marked for seniors. Furthermore, the results indicate that accessibility calculated using a fixed bandwidth would produce patterns of exposure to health care facilities that would be difficult to achieve for suburban seniors given actual mobility patterns.</p> <p>Conclusions</p> <p>The analysis shows large disparities in accessibility between seniors and non-seniors, between urban and suburban seniors, and between vehicle owning and non-owning seniors. This research was concerned with potential accessibility levels. Follow up research could consider the results reported here to select case studies of actual access and usage of health care facilities, and related health outcomes.</p

Noncrossing partitions, toggles, and homomesies

We introduce n(n-1)/2 natural involutions ("toggles") on the set S of non-crossing partitions π of size n, along with certain composite operations obtained by composing these involutions. We show that for many operations T of this kind, a surprisingly large family of functions f on S (including the function that sends π to the number of blocks of π) exhibits the homomesy phenomenon: the average of f over the elements of a T-orbit is the same for all T-orbits. We can apply our method of proof more broadly to toggle operations back on the collection of independent sets of certain graphs. We utilize this generalization to prove a theorem about toggling on a family of graphs called "2-cliquish." More generally, the philosophy of this "toggle-action," proposed by Striker, is a popular topic of current and future research in dynamic algebraic combinatorics

Aortoesophageal fistula after thoracic endovascular aortic repair and transthoracic embolization

Endografts are more commonly being used to treat thoracic aortic aneurysms and other vascular lesions. Endoleaks are a potential complication of this treatment modality and can be associated with aneurysmal sac expansion and rupture. This case report presents a patient who developed a type IA endoleak after endograft repair of a descending thoracic aneurysm. The endoleak was successfully treated through computed tomographic-guided transthoracic embolization, although the patient experienced lower extremity paraparesis postprocedurally. The patient’s endovascular repair was complicated by the development of an aortoesophageal fistula and endograft infection necessitating operative débridement and endograft explantation

Teacher Roles in Personalized Learning Environments.

As school districts, major cities, and entire states in the United States adopt personalized learning as a reform strategy focused on the co-construction of learning opportunities between teachers and students, educators face shifting roles. This study examined the roles of teachers in personalized learning environments within a policy context of statewide legislation of personalized learning plans, flexible educational pathways, and proficiency-based assessment. The study used data from interviews with a purposefully selected group of 20 elementary and middle school teachers from 11 schools. Findings revealed teachers’ perceptions of their roles as (a) empowerers, (b) scouts, (c) scaffolders, and (d) assessors, as well as associated strategies within each role that participants perceived to be constructive. The use of role theory illuminated the potential for intrarole conflict and role strain between and among these roles along with the cultural dimensions of the shift to personalized learning

BEST Endovascular Versus Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI) Trial

The Best Endovascular versus Best Surgical Therapy in Patients with Critical Limb Ischemia trial (BEST-CLI) is an international, prospective, multicentre, multidisciplinary and pragmatic, open-label, superiority-based, comparative-effectiveness randomised controlled trial designed to address the knowledge gap in choosing the appropriate therapy for the treatment of critical limb ischaemia (CLI). This study compares the effectiveness of the best available surgical treatment with the best available endovascular treatment in adults with CLI who are eligible for both treatment options. The study has completed its enrolment phase and patients included in the study are currently being followed up to 50 months. Results of the study promise to provide us with answers to several questions regarding treatment options for patients with CLI, more recently referred to as chronic limb-threatening ischaemia

An Experimental Comparison of Dispute Rates in Alternative Arbitration Systems

This paper reports the results of a systematic experimental comparison of the effect of alternative arbitration systems on dispute rates. The key to our experimental design is the use of a common underlying distribution of arbitrator "fair" awards in the different arbitration systems. This allows us to compare dispute rates across different arbitration procedures where we hold fixed the amount of objective underlying uncertainty about the arbitration awards. There are three main findings. First, dispute rates are inversely related to the monetary costs of disputes. Dispute rates were much lower in cases where arbitration was not available so that the entire pie was lost in the event of dispute. Second, contrary to conventional wisdom, the dispute rate in a final-offer arbitration system is at least as high as the dispute rate in comparable conventional arbitration system. Third, dispute rates are inversely related to the uncertainty costs of disputes. Dispute rates were lower in conventional arbitration treatments where the variance of the arbitration award was higher and imposed greater costs on risk-averse negotiators. Our results can also be interpreted as providing tentative evidence that the negotiators were risk-averse on average.