Natural environments are characterized by daily and seasonal fluctuations in temperature, and ectotherms are expected to adapt to these fluctuations. Moderate temperature fluctuations often accelerate development rate as a result of the Kaufmann effect and possibly additional physiological adaptations. We examined the adaptive potential of ecotype-specific reaction norms by measuring the effect...

Population extinction is of central interest for population dynamics. It may occur from a large rare fluctuation. We find that, in contrast to related large-fluctuation effects like noise-induced interstate switching, quite generally extinction rates in multipopulation systems display fragility, where the height of the effective barrier to be overcome in the fluctuation depends on the system pa...

A study was made of spontaneous renal adenocarcinoma in Rana pipiens collected from natural populations. Previous studies of prevalence have been made on purchased frogs and it is now well documented that renal tumor rate increases with storage. The present study provides tumor data on unstored R. pipiens taken directly from their native habitat. Collections of over 2,000 frogs were made in spr...

Study results from different geographical areas provide some circumstantial evidences that, when compared to general population, people who later in life develop multiple sclerosis (MS) have a pattern of birth excess in spring and late summer, which may disclose an association with MS-predisposing environmental agents. To identify the presence of season-related cluster of MS birth in Sardinia w...

OBJECTIVE To study the seasonal fluctuation of Aedes aegypti and to correlate its abundance with climate conditions. METHODS Samples were weekly collected in ovitraps in the city of Resistencia, Chaco Province, Argentina, between October 2002 and November 2003. The number of eggs collected was correlated with temperature, relative humidity, evaporation and rainfalls recorded. Pearson's correl...

Landfills have the advantage of meeting energy needs birds quickly. They offer easy access to food and widely available throughout year. In this study, were counted using observation points on an open landfill in restored Souk-Ahras region (north-eastern Algeria) for one year from July 2013 April 2014. Seventeen species (17) bird belonging eleven (11) families found: Ciconidae, Corvidae, Accipi...