The Danielson Evaluation System in Two Mid- South High Schools: A Case Study

The purpose of this study is to answer the question: How do pilot users of the Danielson Evaluation System perceive this model in two mid-south high schools? The study describes the perceptions of teachers and administrators who implemented the Danielson Teacher Evaluation Model. The primary focus was on teachers and administrators experience with the pilot of the new Arkansas Teacher Excellence Support System. In an effort to meet requirements under the ESEA flexibility waiver Arkansas developed a comprehensive evaluation model to meet state and federal accountability standards. Arkansas Department of Education developed a pilot school program in which they were afforded the opportunity to explore the teacher evaluation tool in a lived experience in four pilots across the state. The researcher conducted structured open-ended interviews with teachers and building principals. Observations were conducted with research participants. Documents were collected throughout the study to meet triangulation of this phenomenological study. The significant themes (axial codes) that emerged from the data collected were (a) role of the students, (b) teacher evaluation system, (c) emotions of teachers, and (d) reflection of the process. This qualitative study adds new research to the field on the perceptions, experiences, and essence of piloting the Danielson Framework for Teaching Evaluation Model. This research will be instrumental in facilitating more long term research on the perceptions of the framework as a teacher evaluation model. Through this study, readers can gain new insight on the struggle of teachers and administrators as they shift their thinking from the Danielson Framework which guides teacher practices to an evaluation tool. This study provides new research of the everyday challenges of teachers and their effort to improve student achievement

Three-dimensional low Reynolds number flows near biological filtering and protective layers

Mesoscale filtering and protective layers are replete throughout the natural world. Within the body, arrays of extracellular proteins, microvilli, and cilia can act as both protective layers and mechanosensors. For example, blood flow profiles through the endothelial surface layer determine the amount of shear stress felt by the endothelial cells and may alter the rates at which molecules enter and exit the cells. Characterizing the flow profiles through such layers is therefore critical towards understanding the function of such arrays in cell signaling and molecular filtering. External filtering layers are also important to many animals and plants. Trichomes (the hairs or fine outgrowths on plants) can drastically alter both the average wind speed and profile near the leaf's surface, affecting the rates of nutrient and heat exchange. In this paper, dynamically scaled physical models are used to study the flow profiles outside of arrays of cylinders that represent such filtering and protective layers. In addition, numerical simulations using the Immersed Boundary Method are used to resolve the 3D flows within the layers. The experimental and computational results are compared to analytical results obtained by modeling the layer as a homogeneous porous medium with free flow above the layer. The experimental results show that the bulk flow is well described by simple analytical models. The numerical results show that the spatially averaged flow within the layer is well described by the Brinkman model. The numerical results also demonstrate that the flow can be highly 3D with fluid moving into and out of the layer. These effects are not described by the Brinkman model and may be significant for biologically relevant volume fractions. The results of this paper can be used to understand how variations in density and height of such structures can alter shear stresses and bulk flows.Comment: 28 pages, 10 figure

Coordinating Team Tactics for Swarm-vs.-Swarm Adversarial Games

While swarms of UAVs have received much attention in the last few years, adversarial swarms (i.e., competitive, swarm-vs.-swarm games) have been less well studied. In this dissertation, I investigate the factors influential in team-vs.-team UAV aerial combat scenarios, elucidating the impacts of force concentration and opponent spread in the engagement space. Specifically, this dissertation makes the following contributions: (1) Tactical Analysis: Identifies conditions under which either explicitly-coordinating tactics or decentralized, greedy tactics are superior in engagements as small as 2-vs.-2 and as large as 10-vs.-10, and examines how these patterns change with the quality of the teams' weapons; (2) Coordinating Tactics: Introduces and demonstrates a deep-reinforcement-learning framework that equips agents to learn to use their own and their teammates' situational context to decide which pre-scripted tactics to employ in what situations, and which teammates, if any, to coordinate with throughout the engagement; the efficacy of agents using the neural network trained within this framework outperform baseline tactics in engagements against teams of agents employing baseline tactics in N-vs.-N engagements for N as small as two and as large as 64; and (3) Bio-Inspired Coordination: Discovers through Monte-Carlo agent-based simulations the importance of prioritizing the team's force concentration against the most threatening opponent agents, but also of preserving some resources by deploying a smaller defense force and defending against lower-penalty threats in addition to high-priority threats to maximize the remaining fuel within the defending team's fuel reservoir.Ph.D

IB2d : a Python and MATLAB implementation of the immersed boundary method

The development of fluid-structure interaction (FSI) software involves trade-offs between ease of use, generality, performance, and cost. Typically there are large learning curves when using low-level software to model the interaction of an elastic structure immersed in a uniform density fluid. Many existing codes are not publicly available, and the commercial software that exists usually requires expensive licenses and may not be as robust or allow the necessary flexibility that in house codes can provide. We present an open source immersed boundary software package, IB2d, with full implementations in both MATLAB and Python, that is capable of running a vast range of biomechanics models and is accessible to scientists who have experience in high-level programming environments. IB2d contains multiple options for constructing material properties of the fiber structure, as well as the advection-diffusion of a chemical gradient, muscle mechanics models, and artificial forcing to drive boundaries with a preferred motion

Topographic, Bioclimatic, and Vegetation Characteristics of Three Ecoregion Classification Systems in North America: Comparisons Along Continent-wide Transects

Ecoregion classification systems are increasingly used for policy and management decisions, particularly among conservation and natural resource managers. A number of ecoregion classification systems are currently available, with each system defining ecoregions using different classification methods and different types of data. As a result, each classification system describes a unique set of ecoregions. To help potential users choose the most appropriate ecoregion system for their particular application, we used three latitudinal transects across North America to compare the boundaries and environmental characteristics of three ecoregion classification systems [Küchler, World Wildlife Fund (WWF), and Bailey]. A variety of variables were used to evaluate the three systems, including woody plant species richness, normalized difference in vegetation index (NDVI), and bioclimatic variables (e.g., mean temperature of the coldest month) along each transect. Our results are dominated by geographic patterns in temperature, which are generally aligned north–south, and in moisture, which are generally aligned east–west. In the west, the dramatic changes in physiography, climate, and vegetation impose stronger controls on ecoregion boundaries than in the east. The Küchler system has the greatest number of ecoregions on all three transects, but does not necessarily have the highest degree of internal consistency within its ecoregions with regard to the bioclimatic and species richness data. In general, the WWF system appears to track climatic and floristic variables the best of the three systems, but not in all regions on all transects

Occupation and workplace policies predict smoking behaviors: Analysis of national data from the current population survey

OBJECTIVE: Describe differences in smoking behaviors associated with occupation, workplace rules against smoking, and workplace smoking cessation programs. METHODS: We analyzed data from the Current Population Survey- Tobacco Use Supplement surveys from 1992 through 2007. RESULTS: After adjusting for demographic factors, blue-collar workers were at higher risk than white-collar workers for ever smoking, current smoking, and persistent smoking (current smoking among ever smokers). Construction workers were more likely to be current daily smokers than other blue-collar workers. Among ever smokers, current daily smoking was more common in the absence of both workplace rules against smoking and workplace smoking cessation programs. CONCLUSIONS: Social or cultural effects related to occupation are important determinants of smoking. More aggressive promotion of smoking cessation programs and workplace rules prohibiting smoking could have a significant public health impact

Lessons from Laparoscopic Liver Surgery: A Nine-Year Case Series

Objective. This series describes a developing experience in laparoscopic liver surgery presenting results from 40 procedures including right hemihepatectomy, left lateral lobectomy, and microwave ablation therapy. Methods. Forty patients undergoing laparoscopic liver surgery between September 1997 and November 2006 were included. The data set includes: operative procedure and duration, intraoperative blood loss, conversion to open operation rates, length of hospital stay, complications, mortality, histology of lesions/resection margins, and disease recurrence. Results. Mean age of patient: 59 years, 17/40 male, 23/40 female, 23/40 of lesions were benign, and 17/40 malignant. Operations included: laparoscopic anatomical resections n = 15, nonanatomical resections n = 11, microwave ablations n = 8 and deroofing of cysts n = 7. Median anaesthetic time: 120 minutes (range 40–240), mean blood loss 78 mL and 1/40 conversions to open. Median resection margins were 10 mm (range 1–14) and median length of stay 3 days (range 1–10). Operative and 30-day mortality were zero with no local disease recurrence. Conclusion. Laparoscopic liver surgery appears safe and effective and is associated with reduced hospital stay. Larger studies are required to confirm it is oncologically sound

Reifying discrimination on the path to school leadership: Black female principals’ experiences of district hiring/promotion practices

Using intersectionality as a guiding framework, this qualitative study focuses on the hiring/promotion experiences of 20 Black female principals and explores how their hiring/promotion practices reified and/or interrupted traditional discriminatory pathways to school leadership. We find that gendered racism operated across all facets of the principal recruitment and hiring processes in which these women participated. First, relationships and political connections with those already in power (e.g., predominately White men) seemed to be a key mechanism for entering the applicant pool and, later, accessing leadership opportunities. Opportunities were often explicitly racialized such that considerations for leadership positions were stated as being based on the participants being Black. Second, interview processes were frequently described as more performative than substantive with many of the women highlighting questions and comments that reinforced problematic tropes about Black women. Questions also abounded about whether interview panels were reflective of the community and/or if the questions were standardized to ensure fairness and transparency. Finally, district level hiring decisions were frequently disconnected from the interview process and lacked transparency with superintendents, in particular, who overrode or ignored prior steps in, or recommendation from, the school-based part of the process. In this way, findings suggest a hiring/promotion system desperately in need of revision starting with the most basic design features (e.g., standardized interview questions, transparent performance indicators, process accountability via decision-making) and including disrupting discrimination across all facets of the system

Loss of Stathmin-2, a hallmark of TDP-43-associated ALS, causes motor neuropathy

TDP-43 mediates proper Stathmin-2 (STMN2) mRNA splicing, and STMN2 protein is reduced in the spinal cord of most patients with amyotrophic lateral sclerosis (ALS). To test the hypothesis that STMN2 loss contributes to ALS pathogenesis, we generated constitutive and conditional STMN2 knockout mice. Constitutive STMN2 loss results in early-onset sensory and motor neuropathy featuring impaired motor behavior and dramatic distal neuromuscular junction (NMJ) denervation of fast-fatigable motor units, which are selectively vulnerable in ALS, without axon or motoneuron degeneration. Selective excision of STMN2 in motoneurons leads to similar NMJ pathology. STMN2 knockout heterozygous mice, which better model the partial loss of STMN2 protein found in patients with ALS, display a slowly progressive, motor-selective neuropathy with functional deficits and NMJ denervation. Thus, our findings strongly support the hypothesis that STMN2 reduction owing to TDP-43 pathology contributes to ALS pathogenesis