Nassau County Executive Bruce Blakeman signed a new law Monday that places strict limits on tying up dogs and bans outdoor tethering after 11 p.m. — and bad owners could face fines and even jail time. The law — which is believed to be among the strictest in the nation — makes it illegal to chain a dog outside for more than 60 minutes during any 12-hour stretch, and outlaws tethering altogether when temperatures fall below 32 degrees or climb past 90. The law also prohibits tethering any dog that is pregnant, sick, or under 6 months old — and bans keeping any animal tied up outside by itself overnight, from 11 p.m. to 6 a.m. the next morning.