The notions of the penumbra and umbra are important in considering eclipses (q.v.).
In the neighbourhood surrounding the penumbra the granules appear to be packed more closely, forming brilliant patches called faculae.
It is surrounded by the penumbra that receives some light from the light source.
A partial lunar eclipse occurs when the Moon passes into the penumbra, or partial shadow.
Group differences in average volume of ischaemic penumbra salvaged will be analyzed by t-test, adjusting for baseline differences in prognostic variables.