Background: Seasonal rhythms in mood and behavior (seasonality) have been reported to occur in the general population. Seasonal affective disorder, a clinically diagnosed syndrome, is believed to represent the morbid extreme of a spectrum of seasonality. Two types of seasonality have been clinically described: one characterized by a winter pattern and a second by a summer pattern of depressive ...

The blacklegged tick, Ixodes scapularis, is of significant public health importance as a vector of Borrelia burgdorferi, the agent of Lyme borreliosis. The timing of seasonal activity of each immature I. scapularis life stage relative to the next is critical for the maintenance of B. burgdorferi because larvae must feed after an infected nymph to efficiently acquire the infection from reservoir...

PURPOSE Understanding seasonal variation in physical activity is important for informing public health surveillance and intervention design. The aim of the current study was to describe seasonal variation in children's objectively measured physical activity and sedentary time. METHODS Data are from the UK Millennium Cohort Study. Participants were invited to wear an accelerometer for 7 d on f...

Puberty is defined as the awakening of the hypothalamic-pituitary gonadal axis. Sheep are seasonal breeders, experiencing an annual period of reproductive quiescence and renaissance that can be utilized as a model for the onset of puberty. Kisspeptin and gonadotropin-inhibitory hormone appear to be important for the seasonal shift in reproductive activity and the former is mandatory for puberty...

Background: Seasonal differences in step counts have been observed in a limited number of studies conducted on US adults. Due to the diverse global climate, assessment and interpretation of seasonal patterns in ambulatory activity may vary between countries, and regionally specific studies are necessary to understand global patterns. Currently, no studies have assessed whether a seasonal trend ...

Seasonal control of reproduction is critical for the perpetuation of species living in temperate zones that display major changes in climatic environment and availability of food resources. In mammals, seasonal cues are mainly provided by the annual change in the 24-h light/dark ratio (i.e., photoperiod), which is translated into the nocturnal production of the pineal hormone melatonin. The ann...

The rapid emergence and subsequent spread of the novel 2009 Influenza A/H1N1 virus (2009 H1N1) has prompted the World Health Organization to declare the first pandemic of the 21st century, highlighting the threat of influenza to public health and healthcare systems. Widespread resistance to both classes of influenza antivirals (adamantanes and neuraminidase inhibitors) occurs in both pandemic a...

From the recognition of the swine flu pandemic in late April 2009, health professionals, politicians and the public needed to know how serious pandemic (H1N1) 2009 influenza (swine flu) was in relation to other seasonal strains of influenza. The Victorian experience suggests that the circulation of pandemic (H1N1) 2009 influenza in the community was at most like influenza circulation in a seaso...

S easonal variation in the incidence of communicable diseases is among the oldest observations in population biology, dating back at least to ancient Greece, yet our understanding of the mechanisms underlying this phenomenon remains hazy at best. Influenza is perhaps the seasonal disease of most profound interest, because it is responsible for much of the seasonal variation in other infectious ...

Grasses of the subfamily Pooideae, including important cereal crops and pasture grasses, are widespread in temperate zones. Seasonal regulation of developmental transitions coordinates the life cycles of Pooideae with the passing seasons so that flowering and seed production coincide with favorable conditions in spring. This review examines the molecular pathways that control the seasonal flowe...