We study implications of complexity and seasonality in vector-host epidemiological models exhibiting backward bifurcation. Vector-host diseases represent complex infection systems that can vary in the transmission processes and population stages involved in disease progression. Seasonal fluctuations in external forcing factors can also interact in a complex way with internal host factors to gov...

One definition of atypical depression has emphasized the reversed vegetative symptoms (hypersomnia and hyperphagia) (Aarons et al 1985) in the context of a nonendogenous (or mood reactive) depressive state (Ravaris et al 1980). This clinical picture overlaps with Seasonal Affective Disorder (SAD) (Rosenthal et ai 1984), which is a syndrome of recurrent depressions associated with fatigue, hyper...

Previous research has shown that seasonal factors provide one of the most important ways to improve forecast accuracy. For example, in forecasts over an 18-month horizon for 68 monthly economic series from the MCompetition, Makridakis et al. (1984, Table 14) found that seasonal adjustments reduced the MAPE from 23.0 to 17.7 percent, an error reduction of 23%. On the other hand, research has als...

Humans retain neurobiological responses to circadian day-night cycles and seasonal changes in daylength in spite of a life-style usually independent of dawn-dusk signals. Seasonality has been documented in many functions, from mood to hormones to gene expression. Research on seasonal affective disorder initiated the first use of timed bright light as therapy, a treatment since extended to non-s...

Affluent, technically advanced societies have escaped from the effects of nutritional seasonality by means of a cash economy, modern food processing and storage techniques, and worldwide transportation of foodstuffs. However, there remain many areas of the world which are still vulnerable to seasonal food shortages caused by winters or dry seasons when crops cannot be grown. Seasonality is of i...