How Do Heterosexual Undergraduate Students Define Having Sex? A New Approach to an Old Question

This study examined how people define having sex utilizing a new approach to this area of research. A total of 267 men and 327 women rated their degree of confidence that engaging in each of 21 physically intimate behaviors (e.g., penile-vaginal intercourse) counted as “having sex” and then qualitatively explained their reasoning. Separate ratings were made for each behavior when engaged in by the respondent and by his or her partner with someone else. Results showed that, as in previous studies, for both sexes, some behaviors (e.g., penile-vaginal intercourse) were far more confidently rated (i.e., “definitely sex”) than were others (e.g., oral-genital stimulation). Further, both men and women were significantly more certain that a behavior counted as “having sex” when considering their partner's behavior outside the relationship than when they considered their own behavior. Finally, the order in which the two scenarios (i.e., self versus partner) was presented significantly affected participants’ certainty. Qualitative results, paired with quantitative findings, suggest that individuals consider a variety of contextual factors when making these definitional decisions. The methodological and sexual health implications of these results are discussed.     

Rationality from a computational standpoint

A computationally viable choice function possesses, in addition to other important properties, adaptability - as new alternatives become feasible the set of best alternatives corresponding to the new feasible set can be located without having to reconsider previously rejected alternatives. Adaptability is shown to be closely related to, in fact characteristic of, the standard notions of rationality (expressed in terms of transitivity properties). Adaptability provides a generalization of conventional rationality and in addition leads to the choice function proposed by Schwartz, albeit from an entirely different route, that of computational viability.     

Joint Beliefs in Conflictual Coordination Games

The traditional solution concept for noncooperative game theory is the Nash equilibrium, which contains an implicit assumption that players probability distributions satisfy t probabilistic independence. However, in games with more than two players, relaxing this assumption results in a more general equilibrium concept based on joint beliefs (Vanderschraaf, 1995). This article explores the implications of this joint-beliefs equilibrium concept for two kinds of conflictual coordination games: crisis bargaining and public goods provision. We find that, using updating consistent with Bayes rule, players beliefs converge to equilibria in joint beliefs which do not satisfy probabilistic independence. In addition, joint beliefs greatly expand the set of mixed equilibria. On the face of it, allowing for joint beliefs might be expected to increase the prospects for coordination. However, we show that if players use joint beliefs, which may be more likely as the number of players increases, then the prospects for coordination in these games declines vis-à-vis independent beliefs.     

Leveraging risk assessment for foodborne outbreak investigations: The Quantitative Risk Assessment-Epidemic Curve Prediction Model

Root cause analysis can be used in foodborne illness outbreak investigations to determine the underlying causes of an outbreak and to help identify actions that could be taken to prevent future outbreaks. We developed a new tool, the Quantitative Risk Assessment-Epidemic Curve Prediction Model (QRA-EC), to assist with these goals and applied it to a case study to investigate and illustrate the utility of leveraging quantitative risk assessment to provide unique insights for foodborne illness outbreak root cause analysis. We used a 2019 Salmonella outbreak linked to melons as a case study to demonstrate the utility of this model (Centers for Disease Control and Prevention [CDC], 2019). The model was used to evaluate the impact of various root cause hypotheses (representing different contamination sources and food safety system failures in the melon supply chain) on the predicted number and timeline of illnesses. The predicted number of illnesses varied by contamination source and was strongly impacted by the prevalence and level of Salmonella contamination on the surface/inside of whole melons and inside contamination niches on equipment surfaces. The timeline of illnesses was most strongly impacted by equipment sanitation efficacy for contamination niches. Evaluations of a wide range of scenarios representing various potential root causes enabled us to identify which hypotheses, were likely to result in an outbreak of similar size and illness timeline to the 2019 Salmonella melon outbreak. The QRA-EC framework can be adapted to accommodate any food–pathogen pairs to provide insights for foodborne outbreak investigations.