Yes, nosebleeds do tend to occur more often during pregnancy. Pregnancy can cause the blood vessels in your nose to expand, and your increased blood supply puts more pressure on those delicate vessels, causing them to rupture more easily. Although it's unpleasant and inconvenient, an occasional minor nosebleed is generally harmless.
The higher the energy of the gamma rays, the thicker the shielding made from the same shielding material is required. Materials for shielding gamma rays are typically measured by the thickness required to reduce the intensity of the gamma rays by one half (the half value layer or HVL).
I can't see through my skin, but x-rays can easily pass through me, and gamma rays can fcking melt my brain and such. What accounts for the fact that both long-wavelength waves (radio) and short-wavelength waves (x-rays, etc.) can pass through solid objects, but medium-wavelength waves (visible light) cannot?