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This paper extends Brock and Durlauf’s (2001a, 2001b) binary choice complete network (or group interaction) model with homogeneous rational expectations to a general network model with heterogeneous rational expectations. In our model, individuals will form expectations regarding peers’ behaviors taking into account their characteristics. Endogenous, contextual, and correlated effects are all identifiable. This particular study focuses on adolescent smoking behaviors.

Researchers, students, and others in the Models of Infectious Disease Agent Study (MIDAS) create and use computational models to study transmission dynamics of a broad range of infectious diseases. Many MIDAS members are conducting research on COVID-19 and are contributing to an extraordinary international collection of data and information regarding the outbreak. Through its Online Portal for COVID-19 Modeling Research, MIDAS provides access to COVID-19-related data and parameter estimates as well as a software catalog with a list of dashboards and visualizations for following the COVID-19 pandemic.

Preeclampsia, a frequent complication of pregnancy that affects 5%-8% of all gestations, is a leading cause of maternal, and perinatal morbidity and mortality. Over the last decade, it has become clear that preeclampsia is not a single disorder but a syndrome with many etiologies, such as abnormal placentation, utero-placental ischemia, vascular disorders of the placenta, insulin resistance, systemic maternal inflammation, endothelial dysfunction, and imbalance of angiogenic and anti-angiogenic proteins. A case-control longitudinal study was conducted, including 90 patients with normal pregnancies and 76 patients with late-onset preeclampsia (diagnosed at ≥34 weeks of gestation). Maternal plasma samples were collected throughout gestation (normal pregnancy: 2–6 samples per patient, median of 2; late-onset preeclampsia: 2–6, median of 5). The abundance of 1,125 proteins was measured using an aptamers-based proteomics technique. Protein abundance in normal pregnancies was modeled using linear mixed-effects models to estimate mean abundance as a function of gestational age. Data was then expressed as multiples of-the-mean (MoM) values in normal pregnancies. Multi-marker prediction models were built using data from one of five gestational age intervals.

Recent studies suggest the necessity of understanding the interactive effects of predation and productivity on species coexistence and prey diversity. Models predict that coexistence of prey species with different competitive abilities can be achieved if inferior resource competitors are less susceptible to predation and if productivity and/or predation pressure are at intermediate levels. Hence, predator effects on prey diversity are predicted to be highly context dependent: enhancing diversity from low to intermediate levels of productivity or predation and reducing diversity of prey at high levels of productivity or predation. While several studies have examined the interactive effects of herbivory and productivity on primary producer diversity, experimental studies of such effects in predator-prey systems are rare. We tested these predictions using an aquatic field mesocosm experiment in which initial density of the zooplankton predator Notonecta undulata and productivity were manipulated to test their interactive effects on diversity of seven zooplankton, cladoceran species that were common in surrounding ponds. Two productivity levels were imposed via phosphorus enrichment at levels comparable to low and intermediate levels found within neighboring natural ponds. We used open systems to allow for natural dispersal and behaviorally-mediated numerical responses by the flight-capable predator. Effects of predators on zooplankton diversity depended on productivity level. At low and high productivity, prey species richness declined while at high productivity it showed a unimodal relationship with increasing the predator density. Effects of treatments were weaker when using Pielou's evenness index or the inverse Simpson index as measures of prey diversity. Our findings are generally consistent with model predictions in which predators can facilitate prey coexistence and diversity at intermediate levels of productivity and predation intensity. Our work also shows that the functional form of the relationship between prey diversity and predation intensity can be complex and highly dependent on environmental context.