San Francisco Chronicle: Venture investments in clean technology hit a record $2 billion in the second quarter, up nearly 60 percent from a year ago, according to a new report. The investments defy trends seen in other parts of the venture industry, where the amount of money invested in startups is falling and opportunities for companies to go public have dried up. But startups that can enable new sources of energy, clean water and sustainable agriculture will continue to be hot targets for venture …