A Simple Model of Epidemics with Pathogen Mutation

We study how the interplay between the memory immune response and pathogen mutation affects epidemic dynamics in two related models. The first explicitly models pathogen mutation and individual memory immune responses, with contacted individuals becoming infected only if they are exposed to strains that are significantly different from other strains in their memory repertoire. The second model is a reduction of the first to a system of difference equations. In this case, individuals spend a fixed amount of time in a generalized immune class. In both models, we observe four fundamentally different types of behavior, depending on parameters: (1) pathogen extinction due to lack of contact between individuals, (2) endemic infection (3) periodic epidemic outbreaks, and (4) one or more outbreaks followed by extinction of the epidemic due to extremely low minima in the oscillations. We analyze both models to determine the location of each transition. Our main result is that pathogens in highly connected populations must mutate rapidly in order to remain viable.Comment: 9 pages, 11 figure

Chicago Alliance For Equity in Computer Science

Each year, about 14,000 Chicago Public Schools (CPS) students graduate with one year of high school computer science (CS) in fulfillment of the district’s CS graduation requirement. This accomplishment was the culmination of a decade of work by the Chicago Alliance for Equity in Computer Science (CAFÉCS), which includes CPS teachers and administrators, university CS faculty, and educational researchers. CAFÉCS research indicates that CPS significantly increased the capacity of schools to offer the Exploring Computer Science (ECS) introductory course, resulting in a rapid, equitable increase in students’ participation in CS. Making CS mandatory did not negatively impact performance in ECS. Students after the graduation requirement were also equally likely to be inspired to take additional CS coursework, thus doubling the number of students pursuing CS pathways. A large number of these students are now attending the City Colleges of Chicago with increased interest in CS. Recently, CAFÉCS launched a collaboration with Wright College (one of the City Colleges) and Mentor Collective to support students as they transition from CPS to the city colleges. A pilot group of 17 Wright College students are receiving peer mentoring from students at UIC and DePaul

Chicago Alliance For Equity in Computer Science

CAFECS is committed to ensuring that all students in Chicago participate in engaging, relevant, and rigorous computing experiences by addressing problems of practice through research and development that increases opportunities for all students to pursue computing pathways and prepares all students for the future of work

Chicago Alliance For Equity in Computer Science

In 2016, CPS enacted a high school computer science graduation requirement as a means to broaden participation in computer science. ECS is the primary course that supports enactment of this policy. With limited numbers of certified computer science teachers, CPS relied on teachers from a variety of disciplines to teach ECS. The ECS professional development program is designed to prepare teachers from all backgrounds to support student success in ECS. This study examines how the profile of ECS teachers changed and the impact of that change on teachers\u27 experiences with ECS professional development

The Changing Profile of ECS Teachers

This study compares the characteristics and professional development (PD) experiences between teachers who began teaching Exploring Computer Science before and after the enactment of a CS graduation requirement in the Chicago Public Schools. The post-requirement teachers were less likely to have a CS background, but their experience in the ECS PD and their level of confidence at the end of the PD were equivalent to the early adopters

Study of access and outcomes from advanced computer science coursework in the Chicago Public Schools\u27\u27 poster in Structured Poster Session CS for All: An intersectional approach to unpacking equity in computer science education

The Chicago Public Schools (CPS) has taken a unique approach to broadening participation of low-income students, students of color, and girls by establishing Computer Science (CS) as a high school graduation requirement. This policy ensures that all CPS high school students will take a CS course, starting with the class of 2020. However, equity is more than just access. We define equity as equivalence in both the quality and outcomes of CS experiences. Exploring Computer Science (ECS) is the foundational course that fulfills the CPS requirement. Through ECS professional development, the number of qualified ECS teachers has grown. Two years into policy implementation, three-fourths of the schools offered ECS. Our prior research has shown that ECS participation rates by race, gender, and income closely reflect representation of the corresponding populations in CPS. In addition, student performance on the ECS end-of-course assessment was equivalent by race, gender, and income level. This evidence suggests that the CPS graduation policy is contributing towards equitable access to introductory CS with equitable course outcomes. Another outcome of interest is the equitable pursuit of advanced CS. Our primary research question for this poster is the extent to which there is equitable representation and outcomes of students who pursue advanced CS coursework in CPS. In particular, we focused on enrollment in the AP Computer Science A (CSA) and AP Computer Science Principles (CSP) courses from the 2014--15 to the 2017--18 school year. The 2014--15 school year was the first year that the CSP course was pilot tested in CPS, and the 2016--17 school year was the first year that the CSP exam was available. For every student enrolled in either AP CS course, the dataset included race, gender, special education status, English language learner status, free and reduced lunch status, overall GPA, AP course grade, and AP exam score. During the target period, enrollment in CSA declined from a high of 220 to a low of 136 students, while CSP enrollment increased from a pilot of 29 students to 693 students. The combined representation of students by race and gender in both courses was not reflective of the district\u27s student demographics. However, student representation by race and gender was closer to the district representation for CSP than for CSA. We conducted a multiple regression of the factors that correlated with the AP exam performance. The students\u27 overall GPA and the grade in the course were significantly correlated with exam scores. Girls scored statistically lower than boys and Latinx students scored statistically lower than Caucasian, Asian, and African-American students. Students who took ECS prior to CSP scored statistically higher on the CSP exam. These results show promise that using ECS as a foundation course is helpful for students who go on to pursue AP CSP. However, more work needs to be done to capitalize on the success of ECS to encourage CPS schools to offer AP CS courses and to encourage girls and students from underrepresented minority groups to pursue advanced CS coursework

Aggregate Demand and Micro Behavior: A New Perspective on Keynesian Macroeconomics

We analyze the microfoundations for Keynesian aggregate demand effects by considering the link between aggregate demand and firm production decisions under monopolistic competition. Macroeconomic equilibrium is characterized in a simple graphical framework that facilitates comparison of several major approaches to modeling Keynesian microfoundations, including equilibrium theories, "new Keynesian" sticky price models, and more traditional sticky wage approaches. We use this framework to develop an original perspective on aggregate demand effects according to which aggregate demand shocks directly affect the demand conditions and production choices of individual firms. The results require neither nominal rigidity nor expectation errors. Nominal disinflation is ineffective in offsetting the real effects of demand shocks if aggregate demand is insensitive to nominal prices.