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 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...

Abstract. In this work, we used a nonlinear, reduced gravity model of the Gulf of Mexico to study the effect of a seasonal variation of the reduced gravity parameter on ring-shedding behaviour. When small amplitudes of the seasonal variation are used, the distributions of ring-shedding periods are bi-modal. When the amplitude of the seasonal variation is large enough, the ring-shedding events s...

BACKGROUND Seasonal variation in suicidal death has been observed in many countries. In particular, a cyclic variation was found for both men and women in England and Wales in the 1960s and 1970s. Men showed a single 12-month cycle whereas women showed two cycles. AIMS To re-examine the seasonal variation in suicides in England and Wales for the period 1982-1996. METHOD A harmonic analysis ...

OBJECTIVES Eosinophilic esophagitis is a disease associated with dysphagia and has a seasonal variation in incidence. The primary aim of this study was to search for a potential seasonal variation in the incidence of esophageal foreign bodies or food impaction. In addition, after exclusion of structural or accidental causes, the authors sought to explore if such a variation would differ between...

Several recent studies show that seasonal variation and cyclical variation in unemployment are correlated. A common nding is that seasonality tends to diier across the business cycle stages of recessions and expansions. Since seasonal adjustment methods assume that the two sources of variation can somehow be separated, the present study examines the impact of seasonal adjustment on the analysis...

Whether the functional structure of ecological communities is deterministic or historically contingent is still quite controversial. However, recent experimental tests did not find effects of species composition variation on trait convergence and therefore the environmental constraints should play the major role on community convergence into functional groups. Seasonal cerrados are characterize...

this study investigates skull variation in persian jird, meriones persicus (blanford, 1875) in relation to the geoclimatical conditions across its distribution range. the pattern of correlations between geoclimatical variables and geometric shape descriptors for 221 ventral crania was studied by landmark-based geometric morphometric techniques. the covariation between shape and geoclimatical va...

BACKGROUND Previous studies indicate that seasonal variation affects daily physical activity (PA), but none have investigated this relationship in individuals with heart failure (HF) who also have implanted cardioverter defibrillators and cardiac resynchronization therapy (ICD/CRT) devices. The purpose of the present study was to determine if seasonal variation in temperature affects daily PA i...