What does "Activation" refer to in the context of the symptoms of Schizophrenia and Schizoaffective Disorder?
The authors use the Positive and Negative Syndrome Scale (PANSS) to assess symptoms.  One of its cluster scores is activation factor.

Summary:
http://en.wikipedia.org/wiki/Positive_and_Negative_Syndrome_Scale

Original publication of the article, which doesn't list activation factors:
http://schizophreniabulletin.oxfordjournals.org/content/13/2/261.long

Marketed currently here:
http://www.mhs.com/product.aspx?gr=cli&amp;id=overview&amp;prod=panss

None of the sources I saw specified what is meant by activation factor, and many didn't even mention it. It's possible that it's the hyperactivity mentioned in the original publication.  Also, it's possible that it's a modified category in the version sold at the last link. Hopefully this is enough information to get you started, if you want to hunt down the details.