No abstract

The 2016 U.S. presidential primary election, characterized by unexpected results, provides an interesting context to study how citizens are influenced in deciding whether to vote and whom to support. Our aim is to determine which of those changes in voting behavior have the largest impact on the election outcome. We address this question by developing a class of models driven either by the effect of mass media or by social interaction among voters and non-voting members of two parties. The dynamics are modeled using four compartments with a transition matrix describing the evolution of a discrete-time Markov chain. Each model is studied and fit to poll data from the 2012 and 2016 U.S. presidential elections using numerical methods. A comparison across elections indicates that the social influence of each group changes from one election to another, but response to media is similar in both cases.

No abstract

Objective:To use Internet search data to compare duration of compliance for various diets.Design:Using a passive surveillance digital epidemiological approach, we estimated the average duration of diet compliance by examining monthly Internet searches for recipes related to popular diets. We fit a mathematical model to these data to estimate the time spent on a diet by new January dieters (NJD) and to estimate the percentage of dieters dropping out during the American winter holiday season between Thanksgiving and the end of December.Setting:Internet searches in the USA for recipes related to popular diets over a 15-year period from 2004 to 2019.Participants:Individuals in the USA performing Internet searches for recipes related to popular diets.Results:All diets exhibited significant seasonality in recipe-related Internet searches, with sharp spikes every January followed by a decline in the number of searches and a further decline in the winter holiday season. The Paleo diet had the longest average compliance times among NJD (5.32 ± 0.68 weeks) and the lowest dropout during the winter holiday season (only 14 ± 3 % dropping out in December). The South Beach diet had the shortest compliance time among NJD (3.12 ± 0.64 weeks) and the highest dropout during the holiday season (33 ± 7 % dropping out in December).Conclusions:The current study is the first of its kind to use passive surveillance data to compare the duration of adherence with different diets and underscores the potential usefulness of digital epidemiological approaches to understanding health behaviours.

AbstractPrion diseases are lethal neurodegenerative disorders such as mad cow disease in bovines, chronic wasting disease in cervids, and Creutzfeldt-Jakob disease in humans. They are caused when the prion protein PrPC misfolds into PrPSc, which is capable of inducing further misfolding in healthy PrPC proteins. Recent in vivo experiments show that pharmacological chaperones can temporarily prevent this conversion by binding to PrPC molecules, and thus constitute a possible treatment. A second strategic approach uses interferons to decrease the concentration of PrPSc. In order to study the quantitative effects of these treatments on prion proliferation, we develop a model using a non-linear system of ordinary differential equations. By evaluating their efficacy and potency, we find that interferons act at lower doses and achieve greater prion decay rates. However, there are benefits in combining them with pharmacological chaperones in a two-fold therapy. This research is crucial to guide future prion experiments and inform potential treatment protocols.