Diaphragm (optics) curved blades improve the roundness of the iris opening. In a photograph, the number of blades that the iris diaphragm has can be guessed by counting the number of diffraction spikes converging from a light source or bright reflection. For an odd number of blades, there are twice as many spikes as there are blades. In case of an even number of blades, the two spikes per blade will overlap each other, so the number of spikes visible will be the number of blades in the diaphragm used. This is most apparent in pictures taken in the dark with small
Thoracic diaphragm more consistently lower position of the diaphragm increases intra-abdominal pressure which strengthens the lumbar spine. The key to real core stabilization is to maintain the increased IAP while going through normal breathing cycles. […] The diaphragm then performs its breathing function at a lower position to facilitate a higher IAP. Therefore, if a person more consistently lowers their diaphragm, through deep breathing, this can assist strengthening of the core during that period. This can be an aid in strength training and other forms of athletic endeavour. For this reason, taking a deep breath, or adopting a deeper breathing pattern, is