One form of Brazilian Advertising

In my recent trip to centro, I was enthralled by the advertising I encountered. The most frequent one was the person standing on the sidewalk yelling, "dentista!" I heard probably 4 or 5 of these within a 3 block radius, which leads me to believe that either a) people in Belo Horizonte are really in need of dentists or b) this must be a really effective form of advertising. At one point, I had to stop and watch a guy. He was wearing headphones, and totally rocking out to the music, and every 16 counts or so, he would yell "DENTISTA!" I really think he was making the most of a monotonous job.
I told my husband that it must be hard for the shop owners in the vicinity, but then again I think that Brazilians have some magical power to block out annoying noise, which perhaps is accompanied by the ability to produce it....hmmmm....

Other advertising encountered:

-the people yelling "cellularcellularcellular" selling cell phones.

-the cell phone accessory seller (two different products, two different sounds), yelling many things I couldn't understand.

-and my personal favorite, the man selling "widgeo gaymes" or video games.

Yelling and loud noise in advertising is not exclusive to downtown. Just 2 weeks ago I finally was able to figure out a certain sound that I'd been hearing for months in my neighborhood. It was a loud, high pitched whistle followed by shouting. I was walking Sebastian to futsal practice, and I heard it and saw the man! He's the knife sharpener! He sets up his machine on the sidewalk, blows his whistle and yells, and people come for business. I think that there is also a recycling guy that yells, and there are "picole" (popsicle) vendors (they usually have little bells on their carts), and I hear other noises, but I've yet to identify what it is that these people are selling.

I wonder if there are any vendors selling earplugs...