Organically Overhauling my Occupation

After secretly assassinating a wealthy doctor in the countryside, I found myself with surplus funds. Naturally, the best possible investment is investing in oneself, so I boarded a plane and went out to do research for a new job. The problem is, I was boating down a river when I ran into some pirates and was forcefully de-boated. When I came to, I had a busted lip (messing up my pronunciation), a forgotten job, and a wooden plank I was probably researching:

(Click for white background)

As a wanderer of many talents, I could have been doing research for nearly any occupation, but when I spoke the contents of the wooden plank, I remembered my field of research.

What do I research in my new job?

Hint:

This puzzle can be solved without guessing. There is one unique solution. The "x" denotes an empty cell.

• After reading the correct answer, I am still wondering if (rot13) Pyhrf nobhg pbhagel qbpgbe naq cvengrf whfg erq ureevatf? – Gnudiff Dec 27 '19 at 13:30
• @Gnudiff The first part refers to this question, and the second is just a narrative premise for the busted lip. – Avi Dec 27 '19 at 16:19

As Thomas Markov found in their answer,

the completed nonogram consists of an expression that simplifies to $$\log e,$$ where $$\log$$ represents $$\log_{10},$$ next to a letter O.

This can be taken to mean

the phrase "by O, log e," which sounds like the word "biology" if the pronunciation is mangled up a bit, as indicated in the flavortext. So you were most likely researching biology.

In fact, this answer is quite thematic since

it fits the title (biology involves the study of "organic" things) and the rebus itself ("natural log").

• Correct! Nice job noticing the thematic elements :) – Avi Dec 14 '19 at 0:21