The most obvious effect of a recession is that some businesses go away. Weak business plans, poor management or just being in the wrong industry at the wrong time can force companies under.

But a recession also offers strong businesses large and small an opportunity to expand and to grab market share and offer customers more services. Santa Barbara-based small business Jensen Audio Visual has done just that, acquiring a closed-circuit-television surveillance company called TKBIT on Oct. 21.

And Jensen is not alone. Yardi Systems, a Goleta software company with $165   million in 2008 revenue, said Oct.  26 that it acquired another firm. Here’s a closer look at each deal.

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