Summary. 1  Algae are a necessary component of any healthy natural pond ecosystem. 2  However, excessive inputs of nutrients can lead to an overabundance of algae. 3  Excessive growth of filamentous algae, referred to as mats, moss, or scum, is one of the most common problems encountered by pond owners.
From Wikipedia, the free encyclopedia. The history of radiation therapy or radiotherapy can be traced back to experiments made soon after the discovery of x-rays (1895), when it was shown that exposure to radiation produced cutaneous burns.ases sprung up of the development of carcinoma in patients who had used conventional radium therapy up to 40 years after the original treatments. Robley D. Evans made the first measurements of exhaled radon and radium excretion from a former dial painter in 1933.
Palliative radiation therapy is one form of comfort care. This form of radiation isn't used to cure cancer but to treat the symptoms caused by inoperable tumors. This radiation can shrink tumors and alleviate symptoms such as bleeding, spinal cord compressions or obstructions in the throat.