Ciprofloxacin and Levaquin (Levofloxacin) are in the same drug class (fluroquinolones). It makes sense that you would be allergic to both. You probably are allergic to other drugs in the same class such as moxifloxacinI, Ofloxacin, etc.s a fluoroquinolone, it is in the same class of agents as ciprofloxacin, enoxacin, levofloxacin, lomefloxacin, norfloxacin, and ofloxacin. Nalidixic acid is also a quinolone drug.
STC is calculated by taking the Transmission Loss (TL) values tested at 16 standard frequencies over the range of 125 Hz to 4000 Hz and plotted on a graph. Your curve (what you actually measured) is compared to standard STC reference curves (see appendix).
STCs, or Small-scale Technology Certificates, are a commodity that you can use for trade. You can obtain these certificates when you purchase a renewable energy system. Currently, when you install one of these pieces of equipment, solar hot water systems included, you can claim STCs.