School Reform: Leadership through Shared Decision-Making

Educational reform has a long history and schools have gone through cycles of change. This study, however, focuses on the last ten years of reform, often referred to as the restructuring movement. Shared decision making is one of the fundamental changes promoted by this current reform effort. Restructuring the decision-making process to include teachers and parents is a significant change from the hierarchical process that has been in place in most of today\u27s schools. It is time to recognize that schools are complex social institutions that experience change only through its people. By giving those closest to children a stronger voice, decisions would have a greater impact on making the needed changes. This study explored one school that experienced significant change over the course of ten years. This research examines the changing roles of the principal, teachers, and parents as they participated in a shared decision-making process. The strong sense of community that evolved was the result of relationships that were built on trust and respect. The collective sense of responsibility that existed at Valencia Park Elementary School provided the opportunity for leaders and collaborators to practice Rost\u27s postindustrial theory of leadership. A qualitative methodology was used in this study. The case study included interviews, observations, and a review of district and school documents. Through this methodology it was possible to discover how the strong sense of community evolved and how it brought about significant change. The findings of this study indicate that for significant change to occur as a result of shared decision making, a new organizational structure and belief system must be in place, the scope of authority must be clearly delineated, and the critical role the principal plays in facilitating the process must be understood. The shift from a top-down to a shared model of decision making requires the stakeholders to create relationships that foster a collective sense of responsibility. This strong sense of community provides the opportunity for leaders and collaborators to pursue changes that reflect their mutual purposes which relate to meeting the needs of children

Series arc faults in low-voltage AC electrical installations

This thesis provides a complete analysis of all the topics related to series arc faults in low-voltage electrical installations. The part played by series arc faults in the outbreak of hazardous electrical fires is explained by using fire statistics, performing an electrical and thermal characterization of the phenomenon, and comparing with other electrical faults their ability to ignite an insulation material. The analysis demonstrates that the series arc fault generates a heat stress that largely exceeds the ignition threshold of insulation polymers. Other electrical faults such as bolted short-circuit, overload, earth leakage, and glowing fault result in much lower risks of fire ignition. The principles of arc fault detection are explained and the contribution of the active protection AFDD (arc fault detection device) is taken into account in this analysis. The option of achieving a passive protection using appropriate insulation materials is also explored. The performance requirements described in the product standard of AFDD are reviewed and recommendations for improving the standards are proposed.Diese Dissertation ist eine vollständige Analyse der Problematik des seriellen Störlichtbogens in der Niederspannungselektroinstallation. Der Beitrag von seriellen Störlichtbögen in der Entstehung von Elektrobränden wird mit Hilfe der Brandstatistik, der Durchführung der elektrischen und thermischen Charakterisierung des Phänomens und des Vergleichs der Fähigkeit von den anderen elektrischen Fehlern ein Isolierungspolymer zu entzünden, erklärt. Die Analyse beweist, dass der serielle Störlichtbogen eine thermische Beanspruchung erzeugt, die die Zündgrenzen der Isolierungspolymere weitaus überschreitet. Andere elektrische Fehler wie Kurzschlüsse, Überlast, Erdschlüsse und glühende Kontaktstellen ergeben ein wesentlich niedrigeres Brandrisiko. Die Funktionsweise vom Störlichtbogenschutzschalter (auch Brandschutzschalter oder AFDD genannt) wird erklärt und der Beitrag von diesem aktiven Schutz wird in der Analyse berücksichtigt. Der passive Schutz mit geeigneten Isolationsmaterialien wird auch untersucht. Die Anforderungen, die in der Produktnorm für Störlichtbogenschutzschalter beschrieben sind, werden überprüft und Verbesserungen für diese Normen werden vorgeschlagen

Medidas de protección jurídico registral y la disposición de bienes de la unión de hecho por el concubino titular, en la oficina registral de Huánuco, 2020

La presente investigación trata del estudio de las medidas de protección jurídico registral ante la disposición de bienes muebles e inmuebles adquiridos por una unión de hecho no reconocida notarial ni judicialmente. Ante ello, se procedió a realizar un estudio sistemático de las normas del Código Civil en lo que respecta al artículo 326 y lo referente al contrato de compraventa; así como un estudio de la normativa del notariado y de registros públicos. Entre las conclusiones consecuentes se obtuvo que en el Perú existen parejas que deciden unirse como convivientes para hacer vida en común, pero, por diversos factores (que pueden ser materia de otras investigaciones), no realizan el procedimiento notarial o judicial de reconocimiento de uniones de hecho, y, como tal, a esta unión no le son aplicables las seguridades jurídicas dictadas por el gobierno en mérito al artículo 326 del Código Civil

Characteristics of scattered electron beams shaped with a multileaf collimator

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134775/1/mp8046.pd

Calibration and quality assurance for rounded leaf‐end MLC systems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134970/1/mp3517.pd

Lymphatic vasculature mediates macrophage reverse cholesterol transport in mice

Reverse cholesterol transport (RCT) refers to the mobilization of cholesterol on HDL particles (HDL-C) from extravascular tissues to plasma, ultimately for fecal excretion. Little is known about how HDL-C leaves peripheral tissues to reach plasma. We first used 2 models of disrupted lymphatic drainage from skin — 1 surgical and the other genetic — to quantitatively track RCT following injection of [3H]-cholesterol–loaded macrophages upstream of blocked or absent lymphatic vessels. Macrophage RCT was markedly impaired in both models, even at sites with a leaky vasculature. Inhibited RCT was downstream of cholesterol efflux from macrophages, since macrophage efflux of a fluorescent cholesterol analog (BODIPY-cholesterol) was not altered by impaired lymphatic drainage. We next addressed whether RCT was mediated by lymphatic vessels from the aortic wall by loading the aortae of donor atherosclerotic Apoe-deficient mice with [2H]6-labeled cholesterol and surgically transplanting these aortae into recipient Apoe-deficient mice that were treated with anti-VEGFR3 antibody to block lymphatic regrowth or with control antibody to allow such regrowth. [2H]-Cholesterol was retained in aortae of anti–VEGFR3-treated mice. Thus, the lymphatic vessel route is critical for RCT from multiple tissues, including the aortic wall. These results suggest that supporting lymphatic transport function may facilitate cholesterol clearance in therapies aimed at reversing atherosclerosis

Multiplex immunofluorescence to measure dynamic changes in tumor-infiltrating lymphocytes and PD-L1 in early-stage breast cancer.

BACKGROUND: The H&E stromal tumor-infiltrating lymphocyte (sTIL) score and programmed death ligand 1 (PD-L1) SP142 immunohistochemistry assay are prognostic and predictive in early-stage breast cancer, but are operator-dependent and may have insufficient precision to characterize dynamic changes in sTILs/PD-L1 in the context of clinical research. We illustrate how multiplex immunofluorescence (mIF) combined with statistical modeling can be used to precisely estimate dynamic changes in sTIL score, PD-L1 expression, and other immune variables from a single paraffin-embedded slide, thus enabling comprehensive characterization of activity of novel immunotherapy agents. METHODS: Serial tissue was obtained from a recent clinical trial evaluating loco-regional cytokine delivery as a strategy to promote immune cell infiltration and activation in breast tumors. Pre-treatment biopsies and post-treatment tumor resections were analyzed by mIF (PerkinElmer Vectra) using an antibody panel that characterized tumor cells (cytokeratin-positive), immune cells (CD3, CD8, CD163, FoxP3), and PD-L1 expression. mIF estimates of sTIL score and PD-L1 expression were compared to the H&E/SP142 clinical assays. Hierarchical linear modeling was utilized to compare pre- and post-treatment immune cell expression, account for correlation of time-dependent measurement, variation across high-powered magnification views within each subject, and variation between subjects. Simulation methods (Monte Carlo, bootstrapping) were used to evaluate the impact of model and tissue sample size on statistical power. RESULTS: mIF estimates of sTIL and PD-L1 expression were strongly correlated with their respective clinical assays (p \u3c .001). Hierarchical linear modeling resulted in more precise estimates of treatment-related increases in sTIL, PD-L1, and other metrics such as CD8+ tumor nest infiltration. Statistical precision was dependent on adequate tissue sampling, with at least 15 high-powered fields recommended per specimen. Compared to conventional t-testing of means, hierarchical linear modeling was associated with substantial reductions in enrollment size required (n = 25➔n = 13) to detect the observed increases in sTIL/PD-L1. CONCLUSION: mIF is useful for quantifying treatment-related dynamic changes in sTILs/PD-L1 and is concordant with clinical assays, but with greater precision. Hierarchical linear modeling can mitigate the effects of intratumoral heterogeneity on immune cell count estimations, allowing for more efficient detection of treatment-related pharmocodynamic effects in the context of clinical trials. TRIAL REGISTRATION: NCT02950259

SARS-CoV-2 prevalence associated to low socioeconomic status and overcrowding in an LMIC megacity: A population-based seroepidemiological survey in Lima, Peru.

BACKGROUND: Worldwide, Peru has one of the highest infection fatality rates of COVID-19, and its capital city, Lima, accumulates roughly 50% of diagnosed cases. Despite surveillance efforts to assess the extent of the pandemic, reported cases and deaths only capture a fraction of its impact due to COVID-19's broad clinical spectrum. This study aimed to estimate the seroprevalence of SARS-CoV-2 in Lima, stratified by age, sex, region, socioeconomic status (SES), overcrowding, and symptoms. METHODS: We conducted a multi-stage, population-based serosurvey in Lima, between June 28th and July 9th, 2020, after 115 days of the index case and after the first peak cases. We collected whole blood samples by finger-prick and applied a structured questionnaire. A point-of-care rapid serological test assessed IgM and IgG antibodies against SARS-CoV-2. Seroprevalence estimates were adjusted by sampling weights and test performance. Additionally, we performed RT-PCR molecular assays to seronegatives and estimated the infection prevalence. FINDINGS: We enrolled 3212 participants from 797 households and 241 sample clusters from Lima in the analysis. The SARS-CoV-2 seroprevalence was 20·8% (95%CI 17·2-23·5), and the prevalence was 25·2% (95%CI 22·5-28·2). Seroprevalence was equally distributed by sex (aPR=0·96 [95%CI 0·85-1·09, p = 0·547]) and across all age groups, including ≥60 versus ≤11 years old (aPR=0·96 [95%CI 0·73-1·27, p = 0·783]). A gradual decrease in SES was associated with higher seroprevalence (aPR=3·41 [95%CI 1·90-6·12, p<0·001] in low SES). Also, a gradual increase in the overcrowding index was associated with higher seroprevalence (aPR=1·99 [95%CI 1·41-2·81, p<0·001] in the fourth quartile). Seroprevalence was also associated with contact with a suspected or confirmed COVID-19 case, whether a household member (48·9%, aPR=2·67 [95%CI 2·06-3·47, p<0·001]), other family members (27·3%, aPR=1·66 [95%CI 1·15-2·40, p = 0·008]) or a workmate (34·1%, aPR=2·26 [95%CI 1·53-3·35, p<0·001]). More than half of seropositive participants reported never having had symptoms (56·1%, 95% CI 49·7-62·3). INTERPRETATION: This first estimate of SARS-CoV-2 seroprevalence in Lima shows an intense transmission scenario, despite the government's numerous interventions early established. Susceptibles across age groups show that physical distancing interventions must not be relaxed. SES and overcrowding households are associated with seroprevalence. This study highlights the importance of considering the existing social inequalities for implementing the response to control transmission in low- and middle-income countries

Radiation Dose–Volume Effects in the Lung

The three dimensional dose/volume/outcome data for lung are reviewed in detail. The rate of symptomatic pneumonitis is related to many dosimetric parameters, and there are no evident threshold “tolerance dose/volume” levels. There are strong volume and fractionation effects