Mapping Sahelian Floodplain Vegetation from Satellite Imagery

Agriculture/Ecological/Environmental Science (The Ohio State University Denman Undergraduate Research Forum)The intimate connection of vegetation growth and flood dynamics is an integral component of the Logone floodplain in the Far North Region of Cameroon. Vegetation temporal and spatial dynamics are important to the migration patterns of pastoralists as they move into the region to graze cattle. This project’s aim was to create vegetation maps of the dominant perennial grass species (Oryza longistaminata and Echinochloa pyramidalis) to plot their spatial distribution and area within the floodplain. ‘One-class’ classification of a October 2014 Landsat satellite image was performed using ground-truthed vegetation transect data from the same period (collected by Dr. Paul Scholte, DGIZ) with 39 sites composed of the focus vegetation species and 8 sites of other species. Visibly identifiable features of river, rice fields, settlements, and areas of no vegetation were also included and contributed a further 111 training sites. ‘Leave-one-out cross’ validation was performed to analyze model error. The model was applied to classify the entire floodplain, and results indicate the dominant perennial species covered 2650.28km2. The model may be applied to other Landsat images, but only those captured during periods of similar flooding as dynamics of vegetation growth introduce large variation in spectral signature in images outside of this timeframe. Collecting more sites specifically for training may improve the model. Classified maps can illustrate the extent of the perennial grass species and inter-annual vegetation dynamics of the floodplain, which can be used along to investigate the relationship of vegetation within the region’s coupled human and natural system.MORSL Lab, NSF grant (BCS-1211986)Academic Major: HistoryAcademic Major: International Studie

Who Decides Whether Clarity is Clear?: An Analysis of TILA’s Clarity of Disclosure Requirement in Actions by Consumers Against Creditor Card Companies

Section 1 begins by discussing credit card usage and the levels of debt of American consumers. Section 2 outlines the history of TILA, which was promulgated by Congress in 1968, as well as the enforcement power bestowed by Congress on the Federal Reserve Board to implement TILA. This exploration also includes descriptions of Regulation Z and the Schumer Box requirements that state exactly what information needs to be clearly and conspicuously displayed in credit card application materials as well as how the information is to be displayed for consumers to review. Section 3 discusses the recent Ninth Circuit case Rubio v. Capital One where the court decided the clarity of disclosure as a question of law. The dissent from Rubio is also analyzed because the position taken is in accord with the Third Circuit opinion of Roberts v. Fleet Bank, where the clarity of disclosure was left as a question of fact for the jury. Section 4 outlines the Roberts case, and the court’s decision to analyze clarity of disclosure as a question of fact, in more detail. The fifth and final Section recommends leaving clarity of disclosure as a question of fact to be decided by a fact-finder

An Exploration of Communities of Practice in the STEM Teacher Context: What Predicts Ties of Retention?

The STEM teacher workforce in the United States has faced a host of pressing challenges, including teacher shortages, pervasive job dissatisfaction, and high turnover, problems largely attributable to working conditions within schools and districts. These problems have been exacerbated in high-needs districts with fewer resources and more students from low-income communities. Since social network research has shown that workplace relationships are vital for retention, this study investigates the demographic and relational antecedents to what we dub ties of retention. We explore how demographic and relational properties affect the likelihood that teachers have “retention-friendly” networks, characterized by connections important for retention. Our analysis of data from a sample of 120 STEM teachers across five geographic regions identifies key demographics (i.e., site, gender, career changer, and prior teaching experience) and relational properties (network size, positive affect, and perceptions of bridging) associated with ties of retention. We discuss the implications of our findings for the STEM teacher workforce and for teacher education programs

Science and Mathematics Teacher Communities of Practice: Social Influences on Discipline-Based Identity and Self-Efficacy Beliefs

Background Teacher communities of practice, identity, and self-efficacy have been proposed to influence positive teacher outcomes in retention, suggesting all three may be related constructs. Qualitative studies of communities of practice can be difficult to empirically link to identity and self-efficacy in larger samples. In this study, we operationalized teacher communities of practice as specific networks related to teaching content and/or pedagogy. This scalable approach allowed us to quantitatively describe communities of practice and explore statistical relationships with other teacher characteristics. We asked whether these community of practice networks were related to identity and self-efficacy, similar to other conceptualizations of communities of practice. Results We analyzed survey data from 165 in-service K-12 teachers prepared in science or mathematics at 5 university sites across the USA. Descriptive statistics and exploratory factor analyses indicated that math teachers consistently reported smaller communities of practice and lower identity and self-efficacy scores. Correlations revealed that communities of practice are more strongly and positively related to identity than self-efficacy. Conclusion We demonstrate that teacher communities of practice can be described as networks. These community of practice networks are correlated with teacher identity and self-efficacy, similar to published qualitative descriptions of communities of practice. Community of practice networks are therefore a useful research tool for evaluating teacher characteristics such as discipline, identity, self-efficacy, and other possible outcomes (e.g., retention). These findings suggest that teacher educators aiming to foster strong teacher identities could develop pre-service experiences within an explicit, energizing community of practice

The Shape of Galaxy Cluster Dark Matter Haloes: Systematics of Its Imprint on Cluster Gas, and Comparison to Observations

(Abridged) We study predictions for galaxy cluster observables that can test the statistics of dark matter halo shapes expected in a flat LCDM universe. We present a simple analytical model for the prediction of cluster-scale X-ray observations, approximating clusters as isothermal systems in hydrostatic equilibrium, and dark matter haloes as ellipsoids with uniform axial ratios. We test the model against high-resolution, hydrodynamic cluster simulations to gauge its reliability. We find that this simple prescription does a good job of predicting the distribution of cluster X-ray ellipticities compared to the simulations as long as one focuses on cluster regions that are less sensitive to recent mergers. Based on this simple model, the distribution of cluster-size halo shapes expected in the concordance LCDM cosmology implies an X-ray ellipticity distribution with a mean of 0.32 +- 0.01 and a scatter of 0.14 +- 0.01 for the mass range (1-4)x10^{14} Msun/h. We find it important to include the mass dependence of halo shape to make comparisons to observational samples that contain many, very massive clusters. We analyse the systematics of four observational samples of cluster ellipticities and find that our results are statistically compatible with observations. In particular, we find remarkably good agreement between two recent ROSAT samples and LCDM predictions that DO NOT include gas cooling. We also test how well our analytical model can predict Sunyaev-Zel'dovich decrement maps and find that it is less successful although still useful; the model does not perform as well as a function of flux level in this case because of the changing triaxiality of dark matter haloes as a function of radial distance. Both this effect and the changing alignment of isodensity shells of dark matter haloes leave an imprint on cluster gas...Comment: 16 pages, 9 figures; corrected typo (no result affected) submitted to MNRA

Nucleosynthetic osmium isotope anomalies in acid leachates of the Murchison meteorite

We present osmium isotopic results obtained by sequential leaching of the Murchison meteorite, which reveal the existence of very large internal anomalies of nucleosynthetic origin. The Os isotopic anomalies are correlated, and can be explained by the variable contributions of components derived from the s, r and p-processes of nucleosynthesis. Much of the s-process rich osmium is released by relatively mild leaching, suggesting the existence of an easily leachable s-process rich presolar phase, or alternatively, of a chemically resistant r-process rich phase. The s-process composition of Os released by mild leaching diverges slightly from that released by aggressive digestion techniques, perhaps suggesting that the presolar phases attacked by these differing procedures condensed in different stellar environments. The correlation between 190Os and 188Os can be used to constrain the s-process 190Os/188Os ratio to be 1.275 pm 0.043. Such a ratio can be reproduced in a nuclear reaction network for a MACS value for 190Os of ~200 pm 22 mbarn at 30 keV. We also present evidence for extensive internal variation of 184Os abundances in the Murchison meteorite. This suggests that p process rich presolar grains (e.g., supernova condensates) may be present in meteorites in sufficient quantities to influence the Os isotopic compositions of the leachates.Comment: 40 pages, 9 figures, 2 tables. Accepted for publication in Earth and Planetary Science Letter

Improving the visibility of energy use in home heating in England: Thermal images and the role of visual tailoring

publisher: Elsevier articletitle: Improving the visibility of energy use in home heating in England: Thermal images and the role of visual tailoring journaltitle: Energy Research & Social Science articlelink: http://dx.doi.org/10.1016/j.erss.2016.01.005 content_type: article copyright: Copyright © 2016 Elsevier Ltd. All rights reserved

Manganese Superoxide Dismutase: Guardian of the Powerhouse

The mitochondrion is vital for many metabolic pathways in the cell, contributing all or important constituent enzymes for diverse functions such as β-oxidation of fatty acids, the urea cycle, the citric acid cycle, and ATP synthesis. The mitochondrion is also a major site of reactive oxygen species (ROS) production in the cell. Aberrant production of mitochondrial ROS can have dramatic effects on cellular function, in part, due to oxidative modification of key metabolic proteins localized in the mitochondrion. The cell is equipped with myriad antioxidant enzyme systems to combat deleterious ROS production in mitochondria, with the mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) acting as the chief ROS scavenging enzyme in the cell. Factors that affect the expression and/or the activity of MnSOD, resulting in diminished antioxidant capacity of the cell, can have extraordinary consequences on the overall health of the cell by altering mitochondrial metabolic function, leading to the development and progression of numerous diseases. A better understanding of the mechanisms by which MnSOD protects cells from the harmful effects of overproduction of ROS, in particular, the effects of ROS on mitochondrial metabolic enzymes, may contribute to the development of novel treatments for various diseases in which ROS are an important component

CMB-S4: Forecasting Constraints on Primordial Gravitational Waves

CMB-S4---the next-generation ground-based cosmic microwave background (CMB) experiment---is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semi-analytic projection tool, targeted explicitly towards optimizing constraints on the tensor-to-scalar ratio, $r$, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2--3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments given a desired scientific goal. To form a closed-loop process, we couple this semi-analytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for $r > 0.003$ at greater than $5\sigma$, or, in the absence of a detection, of reaching an upper limit of $r < 0.001$ at $95\%$ CL.Comment: 24 pages, 8 figures, 9 tables, submitted to ApJ. arXiv admin note: text overlap with arXiv:1907.0447