Unraveling the Roles of Crayfish Ectosymbionts

Undergraduate Basi

Implementing the STARS Program to Improve Reading Comprehension

The purpose of this action research project was to determine if there is a correlation between the implementation of specific reading comprehension strategies and analysis and practice of specific aspects of reading passages with scores in reading comprehension. The curriculum Strategies To Achieve Reading Success (STARS) was Implemented over an eight week period. To gather baseline data and to assess student progress over the course of the study, the researcher used the Comprehensive Assessment of Reading Strategies (CARS). Analysis of the data collected suggests that the students who were put through the STARS program showed greater gains in reading comprehension than the students in the control group

Was 49b: An Overmassive AGN in a Merging Dwarf Galaxy?

We present a combined morphological and X-ray analysis of Was 49, an isolated, dual AGN system notable for the presence of a dominant AGN Was 49b in the disk of the primary galaxy Was 49a, at a projected radial distance of 8 kpc from the nucleus. Using X-ray data from Chandra, NuSTAR, and Swift, we find that this AGN has a bolometric luminosity of L_bol ~ 2 x 10^45 erg/s, with a black hole mass of M_BH=1.3^{+2.9}_{-0.9} x 10^8 M_Sol. Despite its large mass, our analysis of optical data from the Discovery Channel Telescope shows that the supermassive black hole is hosted by a stellar counterpart with a mass of only 5.6^{+4.9}_{-2.6} x 10^9 M_Sol, making the SMBH potentially larger than expected from SMBH-galaxy scaling relations, and the stellar counterpart exhibits a morphology that is consistent with dwarf elliptical galaxies. Our analysis of the system in the r and K bands indicates that Was 49 is a minor merger, with a mass ratio of Was 49a to Was 49b between 1:7 and 1:15. This is in contrast with findings that the most luminous merger-triggered AGNs are found in major mergers, and that minor mergers predominantly enhance AGN activity in the primary galaxy.Comment: 11 pages, 6 figures, accepted for publication in Ap

Assessing the association between pre-course metrics of student preparation and student performance in introductory statistics: Results from early data on simulation-based inference vs. nonsimulation based inference

The recent simulation-based inference (SBI) movement in algebra-based introductory statistics courses (Stat 101) has provided preliminary evidence of improved student conceptual understanding and retention. However, little is known about whether these positive effects are preferentially distributed across types of students entering the course. We consider how two metrics of Stat 101 student preparation (pre-course performance on concept inventory and math ACT score) may or may not be associated with end of course student performance on conceptual inventories. Students across all preparation levels tended to show improvement in Stat 101, but more improvement was observed across all student preparation levels in early versions of a SBI course. Furthermore, students' gains tended to be similar regardless of whether students entered the course with more preparation or less. Recent data on a sample of students using a current version of an SBI course showed similar results, though direct comparison with non-SBI students was not possible. Overall, our analysis provides additional evidence that SBI curricula are effective at improving students' conceptual understanding of statistical ideas post-course regardless student preparation. Further work is needed to better understand nuances of student improvement based on other student demographics, prior coursework, as well as instructor and institutional variables.Comment: 16 page

Revisiting the vortex-core tunnelling spectroscopy in YBa2_2Cu3_3O7−δ_{7-\delta}

The observation by scanning tunnelling spectroscopy (STS) of Abrikosov vortex cores in the high-temperature superconductor YBa$_2$Cu$_3$O$_{7-\delta}$ (Y123) has revealed a robust pair of electron-hole symmetric states at finite subgap energy. Their interpretation remains an open question because theory predicts a different signature in the vortex cores, characterised by a strong zero-bias conductance peak. We present STS data on very homogeneous Y123 at 0.4 K revealing that the subgap features do not belong to vortices: they are actually observed everywhere along the surface with high spatial and energy reproducibility, even in the absence of magnetic field. Detailed analysis and modelling show that these states remain unpaired in the superconducting phase and belong to an incoherent channel which contributes to the tunnelling signal in parallel with the superconducting density of states.Comment: Final version with supplementary materia

Microbial Assemblages in Association with Crayfish Ectosymbionts

Undergraduat

The Relative Importance of Macroeconomic Shocks, Regional Shocks and Idiosyncratic Risk on Large and Small Banks

Mandatory stress testing has been acclaimed by banking regulators as a key response to preventing future financial crises. Each year banks in the United States with over $50 Billion in assets must perform a Comprehensive Capital Analysis and Review (CCAR) . Banks with over$10 Billion are subject to Dodd-Frank Act Stress Testing (DFAST). This study examne the relative importance of international or national macroeconomic shocks, state-level shocks, and idiosyncratic shocks on mortgage rate charge-offs for the universe of all banks for the 2002-2014 period. We find tha banks with over $10 billion in assets have charge-off rates that are very sensitive to macroeconomic shocks, while those aggregate shocks have almost no power to explain the charge-off rates of smaller banks. The results suggests that bank stress tests are appropriately targeted at only the largest banks whose assets are most responsive to macroeconomic shocks. Smaller bank portfolio performance is driven by idiosyncratic shocks of the sort identified in traditional bank examination. State-level shocks are as or more important in explaining small bank charge-off rates as are national shocks. The findings also support the view that the largest banks are subject to added risk compared to small banks because of the high correlation between large bank loan performance and aggregate shocks, implying that large banks require larger capital reserves

A Method to Estimate Climate-Critical Construction Materials Applied to Seaport Protection

Climate adaptation for coastal infrastructure projects raises unique challenges because global-scale environmental changes may require similar projects to be completed in many locations over the same time frame. Existing methods to forecast resource demand and capacity do not consider this phenomenon of a global change affecting many localities and the resulting increased demand for resources. Current methods do not relate to the most up-to-date climate science information, and they are too costly or too imprecise to generate global, regional, and local forecasts of “climate-critical resources” that will be required for infrastructure protection. They either require too much effort to create the many localized designs or are too coarse to consider information sources about local conditions and structure-specific engineering knowledge. We formalized the concept of a “minimum assumption credible design” (MACD) to leverage available local information (topography/bathymetry and existing infrastructure) and the essential engineering knowledge and required construction materials (i.e., a design cross-section template). The aggregation of the resources required for individual local structures then forecasts the resource demand for global adaptation projects. We illustrate the application of the MACD method to estimate the demand for construction materials critical to protect seaports from sea-level-rise-enhanced storm surges. We examined 221 of the world’s 3,300+ seaports to calculate the resource requirements for a coastal storm surge protection structure suited to current upper-bound projections of two meters of sea level rise by 2100. We found that a project of this scale would require approximately 436 million cubic meters of construction materials, including cement, sand, aggregate, steel rebar, and riprap. For cement alone, ∼49 million metric tons would be required. The deployment of the MACD method would make resource forecasts for adaptation projects more transparent and widely accessible and would highlight areas where current engineering knowledge or material, engineering workforce, and equipment capacity fall short of meeting the demands of adaptation projects

Microbial Assemblages in Association with Crayfish Ectosymbionts

Undergraduate Basi