background: effect of seasonal changes in human reproduction has been intensively researched. some studies acknowledge influences of seasonal variation on natural conception, while others can not confirm them. the aim of this study was to investigate the effect of seasonal changes on different stages of assisted reproductive technology (art) in tehran. materials and methods: this study was carr...

In the paper we consider the role of seasonal intercepts in seasonal cointegration analysis. For the nonseasonal unit root, such intercepts can generate a stochastic trend with a drift common to all observations. For the seasonal unit roots, however, we show that unrestricted seasonal intercepts generate trends that are diierent across the seasons. Since such seasonal trends may not appear in e...

The planning of production capacity for a company has been extensively discussed in literature. Seasonal demand of products or seasonal availability of input materials can make the problem even more challenging, as due to a constant need for capacity adjustments. For example, in contrast to conventional chemical processes, the use of biomass has several distinct characteristics like a time depe...

The species composition of plankton, insect and annual plant communities may vary markedly from year to year. Such interannual variability is usually thought to be driven by year-to-year variation in weather conditions. Here we examine an alternative explanation. We studied the effects of regular seasonal forcing on a multi-species predator-prey model consisting of phytoplankton and zooplankton...

Many health conditions, ranging from psychiatric disorders to cardiovascular disease, display notable seasonal variation in severity and onset. In order to understand the molecular processes underlying this phenomenon, we have examined seasonal variation in the transcriptome of 606 healthy individuals. We show that 74 transcripts associated with a 12-month seasonal cycle were enriched for proce...

Many species of songbirds exhibit dramatic seasonal variation in song output. Recent evidence suggests that seasonal changes in auditory processing are coincident with seasonal variation in vocal output. Here, we show, for the first time, that frequency selectivity and temporal resolution of the songbird auditory periphery change seasonally and in a sex-specific manner. Male and female house sp...

To cope with variations in the environment, most mammalian species exhibit seasonal cycles in physiology and behaviour. Seasonal plasticity during the lifetime contributes to seasonal physiology. Over the years, our ideas regarding adult brain plasticity and, more specifically, hypothalamic plasticity have greatly evolved. Along with the two main neurogenic regions, namely the hippocampal subgr...

In this paper, we present a new time series model, which describes self-exciting threshold autoregressive (SETAR) nonlinearity and seasonality simultaneously. The model is termed multiplicative seasonal SETAR (SEASETAR). It can be viewed as a special case of a general non-multiplicative SETAR model by imposing certain restrictions on the parameters of the latter model. Related to these restrict...

Intervention: The intervention consisted of five weeks of daily sessions of light treatment in the participant’s home. Participants were advised to complete their session before 10:00 each morning, sitting at a distance of 40 cm with the head directed towards the light. The treatment sessions lasted for one hour a day (intensity: 10000 lux at 40 cm) while the placebo involved dim red light for ...

Migratory bird populations are often limited by food during the non-breeding season. Correlative evidence suggests that food abundance on territories varies among years in relation to rainfall, which affects plant productivity and arthropod biomass. At the Font Hill Nature Preserve in Jamaica, we used an irrigation experiment to test the hypothesis that rainfall affects the condition of winteri...