298 research outputs found
Equity in education: Assessing policy efforts in us schools
No full textSchools are in a unique position to identify and address student need in order to ensure all children can fully engage in the classroom learning experience, and it is critical to understand policy efforts aimed at addressing these needs and how they might contribute to valued student outcomes. This dissertation consists of two distinct papers using quantitative policy analysis to examine efforts to provide student support and access to classroom learning.
In Paper 1, I compare several different approaches (e.g., English as a Second Language, bilingual, dual language) to helping English Learners (ELs) achieve proficiency in English and access core curriculum content, as demonstrated by achievement on reading and mathematics standardized assessments. I use two nationally representative longitudinal data sets, the Early Childhood Longitudinal Studies, kindergarten classes of both 1998 and 2010, and utilize propensity score matching to perform a careful comparison of both the groups’ academic performance at each wave of data collection as well as achievement trajectories from kindergarten through third grade. I then perform sensitivity analyses to further ensure the robustness of the findings. I find that students in all settings generally demonstrate similar achievement in early elementary grades as well as similar growth trajectories, and findings are robust to the presence of all but the most extreme of possible omitted variables. Importantly, students in programs involving instruction in students’ first language did not demonstrate lower achievement than those in English-only settings. Finally, I discuss the implications of this work for informing policy decisions regarding services provided to ELs.
In Paper 2, I examine a new federal policy expanding free school breakfast and lunch offerings, the Community Eligibility Provision of the Healthy, Hunger-Free Kids Act of 2010, which has particular importance for children from low-income families, and its relationship with student attendance. Specifically, I focus on the first three years the program was available in Illinois, one of the first states eligible for participation. I use a difference-in-differences ordinary least-squares regression approach to estimate the relationship between program participation and student attendance amongst eligible schools, and I then use an instrumental variables approach to examine the relationships between participation and attendance amongst all schools in the state. Findings indicate that expanded access to free school breakfast and lunch is associated with increased attendance at participating schools both overall and for several student subgroups in particular. As attendance is positively associated with other valued student outcomes, such as academic achievement and attainment, these findings are promising in highlighting how students can be positively affected by this federal policy effort.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-05-01The student, Jennifer Timmer, accepted the attached license on 2018-04-15 at 23:11.The student, Jennifer Timmer, submitted this Dissertation for approval on 2018-04-15 at 23:15.This Dissertation was approved for publication on 2018-04-17 at 12:18.DSpace SAF Submission Ingestion Package generated from Vireo submission #12260 on 2018-08-31 at 17:29:08Made available in DSpace on 2018-09-04T20:47:15Z (GMT). No. of bitstreams: 3
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Blowin' in the wind
No full textThe new Open Jet Facility wind tunnel, which is scheduled to blow its first wind on 24 October, has been a project in the mind of designer Nando Timmer for over twenty years. "I have had moments when I thought it was never going to happen.
Relationship of lesser prairie-chicken density to landscape characteristics in Texas
No full textGround-based lek surveys have traditionally been used to index trends in prairie
grouse populations (Centrocercus and Tympanuchus spp.). However, indices of
abundance or density can be fundamentally flawed and techniques that account for
incomplete detection should be used. Distance sampling is a common technique used to
estimate the density and abundance of animal populations and has been used with aerial
surveys to monitor avian populations. With an increase in renewable energy
development in native prairies and sagebrush steppe, there is a greater need to effectively
monitor prairie grouse populations. One such species, the lesser prairie-chicken (LPC; T.
pallidicinctus), has faced significant population declines and is thus, a species of
conservation concern. In addition, much of the current and proposed wind energy
development in the Great Plains overlaps some of the extant LPC distribution and few
peer-reviewed studies have been conducted to investigate this potential threat to LPCs.
Hierarchical distance sampling models can relate LPC lek density to landscape features
and help predict the potential impact from wind and other energy development on lek
density. Thus, the main objectives of our study were to estimate lek density in the LPC
range in Texas and model anthropogenic and landscape features associated with lek
density. We accomplished this by flying helicopter lek surveys for 2 field seasons and
employing a line-transect method developed at Texas Tech University.
We inventoried 208, 7.2 km × 7.2 km survey blocks and detected 71 new leks, 25
known leks, and observed 5 detections outside the current LPC range. We estimated 2.0
leks/100 km2 (90% CI = 1.5–2.8 leks/100 km2) and 12.3 LPCs/100 km2 (90% CI = 8.5–
17.9 LPCs/100 km2) for our sampling frame. Our state-wide abundance estimates were
Texas Tech University, Jennifer M. Timmer, May 2012
vii
301.9 leks (90% CI = 219.4–415.4 leks) and 1,822.4 LPCs (90% CI = 1,253.7–2,649.1
LPCs). Our best model indicated lek size and lek type (wi = 0.360) influenced lek
detectability. Lek detectability was greater for larger leks and natural leks rather than
man-made leks. We used hierarchical distance sampling to build spatially-explicit
models of lek density and landscape features. The 2 most competitive models included
percent shrubland + transmission line (>69kv) density and only percent shrubland (AIC=
943.817, wi = 0.486; AIC = 945.098, wi = 0.256, respectively). We model-averaged our
most competitive models and estimated the number of leks in our sampling frame at
245.7 leks (cv = 0.137). Lek density peaked at lower levels of transmission line density
and where ≈60% of the landscape was composed of shrubland patches (shrubs <5 m tall
comprising ≥20% of the total vegetation). Our state-wide survey efforts provide wildlife
managers and biologists with population estimates, new lek locations, and identified
spatially-explicit predictions of lek density. Our spatially-explicit models predicted lek
density based on percent shrubland and transmission line density, which can be used to
predict how lek density may change in response to transmission line development and
changes in habitat conditions.
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Targeting FPR1 and CXCR4 in cancer and the contribution of the tumor microenvironment
No full textSolid tumors can be primarily resistant or could become resistant to therapy, due to the protective effect of their direct tumor environment, which is called the microenvironment. UMCG-researcher Jennifer Boer studied the interaction of glioblastoma (GBM) and prostate cancer cells with their tumor microenvironment. In this context she investigated the role of two membrane bound proteins (receptors) called formyl peptide receptor-1 (FPR1) and chemokine receptor-4 (CXCR4). From laboratory research it became evident that both receptors are involved in the migration and possible dissemination of tumor cells, which migrate towards their ligands present in the microenvironment. The ligands for FPR1 are formyl-methionil-leucine-lysine-isoleucine-valine (fMLKLIV) and formyl-methionil-methionil-tyrosine-alanine-leucine-phenylalanine (fMMYALF), which are released when unregulated cell death occurs. Jennifer Boer used the chemotaxis inhibitory protein of S. aureus (CHIPS), in order to inhibit the migration of FPR1-positive tumor cells. In a preclinical setting the use of this bacterial derived protein led to a slight survival improvement. When CXCR4 is activated by its ligand CXCL12, the receptor contributes to tumor cell mobility but also to therapy resistance mediated by the tumor microenvironment. The CXCR4 inhibitor AMD3100 transiently sensitizes prostate cancer cells to radiation therapy but eventually leads to an increase of circulating tumor cells. According to Jennifer Boer this is an important aspect that should be taken in consideration when designing future clinical trials that involve the use of CXCR4 inhibitors. She concludes that therapies targeting FPR1 and CXCR4 may contribute to the development of new cancer treatments
Achieving energy neutrality: is it gender neutral? The consideration of gender in the policymaking processes of the energy transition in the municipality of Nijmegen
No full textWith the energy transition being one of the most important tools to take action on the climate crisis, it becomes increasingly important that it’s done in a just and equitable way. This is not always easy to achieve: energy transition policymaking processes are not neutral, but influenced by power structures and thus inequalities might persist in these processes. The existence of gender norms leads to gendered energy needs and creates barriers to participate in the energy transition policymaking process, thus breeding inequality when this is not acknowledged. This research aims to find out if a gendered dimension of the energy transition is taken into consideration in policymaking processes of energy transition policies in the municipality of Nijmegen. Through semi-structured interviews with policymakers and a content analysis on policy documents, it was established that the municipality of Nijmegen does not really consider gender an important aspect in their energy transition policymaking process. While having gender diverse institutional representation and plans that describe wanting to include everyone, gendered energy needs are barely acknowledged and participation processes in the municipality lack diversity. These may become more inclusive through the consideration of gender in communication strategies, leading to more just energy transition policymaking processes
Study on aerodynamic imbalance of wind turbine rotors: An investigation of effects due to blade pitch assymetry.
No full textEWEMWind EnergyAerospace Engineerin
An overview of NACA 6-digit airfoil series characteristics with reference to airfoils for large wind turbine blades
No full textThis paper investigates the NACA 63 and 64 6-digit series of airfoils tested in the NACA LTPT in view to verify the RFOIL calculated airfoil characteristics for high Reynolds numbers. Some anomalies in the zero-lift angles of 15% and 18% thick airfoils from these series are identified, both in the airfoil clean case and in case of wrap-around roughness. It is found that RFOIL predicts the maximum lift coefficient at a Reynolds number of 3 million well, but consistently under predicts the Cl,max for Reynolds numbers of 6 and 9 million. It is, however, based on other comparisons at high Reynolds numbers unclear if this is due to an inability of the prediction code or to a deviation in the test results. The drag coefficient is under predicted with about 9% for a wide range of airfoils and Reynolds numbers. Due to wrap-around roughness the maximum lift coefficient decreases with 18% to 20%.Aerospace Design, Integration and OperationsAerospace Engineerin
Aerodynamic and Aeroelastic Design of Low Wind Speed Wind Turbine Blades
No full textA large number of wind energy installations exist on rich wind resource sites. Nevertheless, estimates show that about 50% of the world’s wind energy resource has a wind speed of 7 m/s or less. For these low wind speed resource areas, low wind turbine technology is required. For this reason, this DTU Wind Energy master project, in cooperation with Ming Yang Wind Power European R&D Centre ApS, looks into the design of a low wind speed wind turbine blade. The project’s goal is to design a wind turbine blade for a 2 MW wind turbine, with a rotor diameter of 115 meters. A site, in China, is also proposed for the wind turbine design. The project focuses on the design of a blade for low wind speed wind turbine applications, on sites with a mean wind speed of about 7 m/s. The project includes several stages. First an introduction to the blade design and blade optimisation methods are introduced. Afterwards, the provided site in China is assessed and key parameters are selected for the next project stages. The next step, involves the wind turbine design, provided by Ming Yang Wind Power. This one is reviewed by doing an aerodynamic and aero-elastic performance analysis. With a cost of energy approach, a new wind turbine blade, for a wind turbine with a rated power of 2MW, is designed. Finally, an aerodynamic and aero-elastic performance analysis of the new blade, under different wind conditions, is performed to assess its feasibility. The framework is carried out with HAWC2, developed by DTU, and compared to GH Bladed, at some of the design stages.European Wind EnergyDUWINDAerospace Engineerin
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