The halogen gas inside a halogen lamp causes the evaporated tungsten to redeposit on the filament. This process, along with high pressure inside the capsule, slows down deterioration of the filament, improves lumen maintenance and extends the lampâs service life.
The mean heart rate as obtained in this study (246 beats min â1, with a range of 207â314 beats min â1) is within the range given by several authors in chicken embryos. In a previous study () we reported heart rate values ranging between 250 and 270 beats min â1 on days 19 and 20 of incubation.
The approximate fetal heart rate for weeks 5 to 9 (assuming a starting rate of 80): 1  Week 5 starts at 80 and ends at 103 bpm. 2  Week 6 starts at 103 and ends at 126 bpm. 3  Week 7 starts at 126 and ends at 149 bpm. 4  Week 8 starts at 149 and ends at 172 bpm. 5  At week 9 the embryonic heart tends to beat within a range of 155 to 195 bpm.