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...

Background There are few quantitative documents about the seasonal incidence of tuberculosis (TB) among immigrant populations. Concerning the significant role of recognizing seasonal changes of TB in improving the TB control program, this study determines the trend and seasonal temporal changes of TB among immigrants entering Iran.   Methods In this longitudinal study, data from the Iranian TB ...

REPLY We thank Kok, Umans, and Arnold for their statistical calculations. Indeed, a large sample size would be required to prove that there is equivalence in clinical outcome between patients directly admitted compared to transferred patients. To demonstrate that the six-month mortality rate would not exceed more than 1% (6% vs. 7%) would require a sample size of even more than 25,000 patients!...

A study was conducted to determine the copper status of different classes of grazing sheep during twodifferent seasons on a farm located in southern Punjab, Pakistan. A complete free-choice supplement wasavailable to all animals throughout the year. Soil, forage and blood plasma from animals were taken eighttimes during the year (2005) (four times in both summer and winter seasons). Soil Cu2+ w...