Emerging Challenges and Opportunities in Infectious Disease Epidemiology.

Much of the intellectual tradition of modern epidemiology stems from efforts to understand and combat chronic diseases persisting through the 20th century epidemiologic transition of countries such as the United States and United Kingdom. After decades of relative obscurity, infectious disease epidemiology has undergone an intellectual rebirth in recent years amid increasing recognition of the threat posed by both new and familiar pathogens. Here, we review the emerging coalescence of infectious disease epidemiology around a core set of study designs and statistical methods bearing little resemblance to the chronic disease epidemiology toolkit. We offer our outlook on challenges and opportunities facing the field, including the integration of novel molecular and digital information sources into disease surveillance, the assimilation of such data into models of pathogen spread, and the increasing contribution of models to public health practice. We next consider emerging paradigms in causal inference for infectious diseases, ranging from approaches to evaluating vaccines and antimicrobial therapies to the task of ascribing clinical syndromes to etiologic microorganisms, an age-old problem transformed by our increasing ability to characterize human-associated microbiota. These areas represent an increasingly important component of epidemiology training programs for future generations of researchers and practitioners

N = 7 On-shell diagrams and supergravity amplitudes in momentum twistor space

We derive an on-shell diagram recursion for tree-level scattering amplitudes in N = 7 supergravity. The diagrams are evaluated in terms of Grassmannian integrals and momentum twistors, generalising previous results of Hodges in momentum twistor space to non-MHV amplitudes. In particular, we recast five and six-point NMHV amplitudes in terms of N = 7 R-invariants analogous to those of N = 4 super-Yang-Mills, which makes cancellation of spurious poles more transparent. Above 5-points, this requires defining momentum twistors with respect to different orderings of the external momenta

The Phantom Burster Model for Pancreatic β-Cells

Abstract Pancreatic β-cells exhibit bursting oscillations with a wide range of periods. Whereas periods in isolated cells are generally either a few seconds or a few minutes, in intact islets of Langerhans they are intermediate (10–60 s). We develop a mathematical model for β-cell electrical activity capable of generating this wide range of bursting oscillations. Unlike previous models, bursting is driven by the interaction of two slow processes, one with a relatively small time constant (1–5 s) and the other with a much larger time constant (1–2 min). Bursting on the intermediate time scale is generated without need for a slow process having an intermediate time constant, hence phantom bursting. The model suggests that isolated cells exhibiting a fast pattern may nonetheless possess slower processes that can be brought out by injecting suitable exogenous currents. Guided by this, we devise an experimental protocol using the dynamic clamp technique that reliably elicits islet-like, medium period oscillations from isolated cells. Finally, we show that strong electrical coupling between a fast burster and a slow burster can produce synchronized medium bursting, suggesting that islets may be composed of cells that are intrinsically either fast or slow, with few or none that are intrinsically medium

Unleash Physical Limitations: Virtual Emergency Preparedness Planning Simulation Training, Methodology and a Case Study

Simulation is perhaps the most widely used method for training emergency management workers. Despite its wide application, traditional simulation suffers from several constraints and limitations, which motivate us to pursue a different way – virtual simulation, as an alternative and supplement for the traditional training method. Utilization of groupware, network, and other information technologies makes virtual simulation more flexible and easier to prepare. Although virtual simulation can overcome some of the constraints related to physical simulation, so far there are little evidences that this new method can achieve similar or even better training effects compared with traditional simulation training method. To test the effects of this new training approach and the methodology to run it, several pilot trials have been conducted in the U.S. and Europe. This article is an exploratory study of a pilot emergency preparedness planning virtual simulation conducted in NJIT in late 2004. This study will help us understand the nature of virtual simulation, and help us improve the theories and designs of virtual simulation for emergency preparedness

Book Reviews

THE IMPEACHMENT AND TRIAL OF ANDREW JOHNSON. By Michael Les Benedict. New York: W.W. Norton and Company, 1973. Pp. x, 212. $6.95. 1973 LEGAL MEDICINE ANNUAL. Edited by Cyril H. Wecht. New York: Appleton-Century Crofts, 1973. Pp. xv, 522.$19.25. CASE HISTORIES IN CONSTRUCTION LAW-A GUIDE FOR ARCHITECTS, ENGINEERS, CONTRACTORS, BUILDERS. By William Jabine. Boston: Cahners Books, 1973. Pp. vi, 233. $12.50. COURTS ON TRIAL-MYTH AND REALITY IN AMERICAN JUSTICE. By Jerome Frank. Princeton: Princeton University Press, 1973. Pp. xii, 441.$15.00 cloth. ($3.45 paperback)

Temporal trends in symptom experience predict the accuracy of recall PROs

Objective - Patient-reported outcome measures with reporting periods of a week or more are often used to evaluate the change of symptoms over time, but the accuracy of recall in the context of change is not well understood. This study examined whether temporal trends in symptoms that occur during the reporting period impact the accuracy of 7-day recall reports. Methods - Women with premenstrual symptoms (n = 95) completed daily reports of anger, depression, fatigue, and pain intensity for 4 weeks, as well as 7-day recall reports at the end of each week. Latent class growth analysis was used to categorize recall periods based on the direction and rate of change in the daily reports. Agreement (level differences and correlations) between 7-day recall and aggregated daily scores was compared for recall periods with different temporal trends. Results - Recall periods with positive, negative, and flat temporal trends were identified and they varied in accordance with weeks of the menstrual cycle. Replicating previous research, 7-day recall scores were consistently higher than aggregated daily scores, but this level difference was more pronounced for recall periods involving positive and negative trends compared with flat trends. Moreover, correlations between 7-day recall and aggregated daily scores were lower in the presence of positive and negative trends compared with flat trends. These findings were largely consistent for anger, depression, fatigue, and pain intensity. Conclusion - Temporal trends in symptoms can influence the accuracy of recall reports and this should be considered in research designs involving change

Psychometric characteristics of daily diaries for the Patient-Reported Outcomes Measurement Information System (PROMIS®): a preliminary investigation

Purpose - The Patient-Reported Outcomes (PRO) Measurement Information System (PROMIS®) has developed assessment tools for numerous PROs, most using a 7-day recall format. We examined whether modifying the recall period for use in daily diary research would affect the psychometric characteristics of several PROMIS measures. Methods - Daily versions of short-forms for three PROMIS domains (pain interference, fatigue, depression) were administered to a general population sample (n = 100) for 28 days. Analyses used multilevel item response theory (IRT) models. We examined differential item functioning (DIF) across recall periods by comparing the IRT parameters from the daily data with the PROMIS 7-day recall IRT parameters. Additionally, we examined whether the IRT parameters for day-to-day within-person changes are invariant to those for between-person (cross-sectional) differences in PROs. Results - Dimensionality analyses of the daily data suggested a single dimension for each PRO domain, consistent with PROMIS instruments. One-third of the daily items showed uniform DIF when compared with PROMIS 7-day recall, but the impact of DIF on the scale level was minor. IRT parameters for within-person changes differed from between-person parameters for 3 depression items, which were more sensitive for measuring change than between-person differences, but not for pain interference and fatigue items. Notably, mean scores from daily diaries were significantly lower than the PROMIS 7-day recall norms. Conclusions - The results provide initial evidence supporting the adaptation of PROMIS measures for daily diary research. However, scores from daily diaries cannot be directly interpreted on PROMIS norms established for 7-day recall