[1] A single-particle soot photometer (SP2) was flown on a NASA WB-57F high-altitude research aircraft in November 2004 from Houston, Texas. The SP2 uses laser-induced incandescence to detect individual black carbon (BC) particles in an air sample in the mass range of $3-300 fg ($0.15-0.7 mm volume equivalent diameter). Scattered light is used to size the remaining non-BC aerosols in the range of $0.17-0.7 mm diameter. We present profiles of both aerosol types from the boundary layer to the lower stratosphere from two midlatitude flights. Results for total aerosol amounts in the size range detected by the SP2 are in good agreement with typical particle spectrometer measurements in the same region. All ambient incandescing particles were identified as BC because their incandescence properties matched those of laboratory-generated BC aerosol. Approximately 40% of these BC particles showed evidence of internal mixing (e.g., coating). Throughout profiles between 5 and 18.7 km, BC particles were less than a few percent of total aerosol number, and black carbon aerosol (BCA) mass mixing ratio showed a constant gradient with altitude above 5 km. SP2 data was compared to results from the ECHAM4/MADE and LmDzT-INCA global aerosol models. The comparison will help resolve the important systematic differences in model aerosol processes that determine BCA loadings. Further intercomparisons of models and measurements as presented here will improve the accuracy of the radiative forcing contribution from BCA.Citation: Schwarz, J. P., et al. (2006), Single-particle measurements of midlatitude black carbon and light-scattering aerosols from the boundary layer to the lower stratosphere,

the Southeast Transportation Workforce Center and the West TN STEM Hub. Her technical research includes focus on journey to school in urban areas, transportation planning (particularly related to freight impacts), livability assessment in urban communities, and strategies to engage citizens in the transportation planning process. She has a strong record of STEM workforce and education research, with special emphasis on transportation workforce development, partnerships between industry and academia, and increasing representation of women and underrepresented minorities in STEM.

In this paper, we study the effect of a new first-year program on student retention rates in engineering. First-year engineering students face unique challenges attending a university. In fact, research shows that the dropout rate among first year students is the highest in engineering programs. To be able to increase retention rates, it is important to understand the reasons engineering students are not completing their programs. This is a rising concern in all engineering programs across the nation. We believe that the lack of hands-on, team-based experiences in a typical first-year engineering curriculum is one of the main reasons students leave the program after completing their first year. Furthermore, it is difficult for the first-year students to connect the concepts of math and science with engineering. Therefore, we need a first-year engineering curriculum that can fill the gap between the fundamentals of abstract math and physics and the application of those fundamentals in solving engineering problems. Thus, we have created a first-year learning community as a solution to low retention rates in engineering. In this learning community, the first-year students take the following courses together: • An interdisciplinary freshman experiences course, in which we teach the concept of "Design-Build-Test-Improve-Collaborate" to the students. The students take the ownership of their group projects, while working together and building friendships that last. • An appropriate Math course (Calculus or Pre-Calculus), which is specifically designed to address the applications of math in engineering. • An English composition class, which focuses on "Writing in Engineering". The main goal of this research is to improve the retention rate of first-year engineering students, by developing a first-year engineering curriculum that can provide additional support and unique learning opportunities in students' entry-level classes. Introduction: Faculty in the College of Engineering and Applied Science (CEAS) at the University of Colorado Denver (CU Denver) have developed a new engineering program for first-year students. The program is titled the Engineering Learning Community (ELC) and is designed to support incoming freshmen engineering and pre-engineering students. In this paper the methods, results and conclusions of the first two academic years of the program are presented. The ELC program was piloted in the fall of 2016 (2016 ELC) and was expanded and run again in the fall of 2017 (2017 ELC).

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In this evidence-based practice paper, we explore the first three years of an Engineering Learning Community (ELC). The research group at our University recognizes the need to increase retention rates at the Engineering College and has created the ELC to support increased retention. Three cohorts of ELC students have been observed to determine the potential success of this project. The results from this study indicate that participation in the ELC is beneficial for first-year college students in engineering. First year grade point average (GPA) is strongly related to first year retention in engineering at our University as shown through a binary logistic regression model. Despite a small sample size for the ELC group, results show that first year freshman students participating in the ELC have a higher average GPA at the end of their first year when compared to the rest of the students in the Engineering College. Our model indicates a higher probability of being retained beyond the first year as a result of having higher GPA, and when ELC participation is included, the model suggests a positive effect on retention as well. We also observe that the ELC students have higher retention rates for the three cohorts in this study, which supports the results from our regression model. Interviews with three students from the sample reveal various positive impacts of ELC participation including: improved social experiences, access to resources and mentoring, and valuable support for the transition from high school to college, all of which may have contributed to higher GPA for this group.