The reliability assessment of infrastructure systems providing power, natural gas, and potable water is an integral part of societal preparedness to unforeseen hazards. The topological properties of interface networks connecting electric substations to water pumping stations and natural gas compressors have received little attention, despite the key role these connections play in operation and failure propagation. This work introduces a performance assessment methodology for coupled infrastructures that links physical fragility modeling with the topology of realistic and ideal connecting interfaces. Distinct interfaces based on features such as betweenness, clustering, vertex degree, and Euclidean distance are assessed regarding their role in connecting utility systems and propagating failures from random and hurricane events in Harris County, Texas. The interface minimizing the Euclidean distance between electric substations and other utility nodes exhibits a slow performance decline as random failures i...

Nearly two-thirds of persons who receive an unsolicited ballot in the mail before Election Day choose to return their ballot in person, rather than through the less costly and more convenient U.S. Postal Service. Why? How and when voters choose to return their mail ballot is consequential to the administration of elections and the confidence voters have in the outcome of elections. We offer and test four explanations for how vote by mail voters choose to return their ballot, including the social rewards of voting, the costs of voting, trust in U.S. Postal Service and a preference to cast a ballot after campaigning ends. We find supporting evidence for each explanation conditioned by prior history of voting.