Arsenic is present in the environment as a naturally occurring substance or as a result of contamination from human activity. It is found in water, air, food, and soil in organic and inorganic forms.
Latent Semantic Analysis (LSA), sometimes referred to as Latent Semantic Indexing (LSI), is an information modeling and analysis technology. It enables you to organize and examine large collections of information based on meaning (semantics), not just matching the words or items being used.
First, LSA Shell is the friendly name for our old pal lsass.exe. As you've seen, we typically hear of it in conjunction with the Sasser worm and other viruses. For various reasons many viruses cause issues that appear to manifest as problems with lsass.exe.