Solar charge times are determined by the total area and efficiency of the solar cells -- the Spark uses high-efficiency monocristalline cells which will charge an iPad from about 10 hours of sunshine.

ENGADGET: Voltaic Spark Tablet Case powers your pad with the Sun's rays

The new tablet snaps easily and securely into existing IT environments to help improve IT efficiency and decrease total cost-of-ownership.

ENGADGET: Dell Latitude 10 essentials trim pushes pro Windows 8 tablets down to $499 (video)

With paper-based systems you cannot have the types of efficiency we associate with Deming or the total production system.

FORBES: Newt Gingrich

In the residential sector, combined with the home Energy Efficiency Scheme and Boiler Scrappage Scheme, a total of 25, 000 Welsh homes were improved and made cheaper to heat during 2010-11.

BBC: Debate on climate change

Total could also take the mantle, but while ExxonMobile has a history of timely efficiency in its projects, the Kazhak government probably fears a loss of bargaining power by letting the biggest oil and gas company in the world take control of its gas field.

FORBES: Kazakhstan Not Doing Eni Good

Existing techniques and technologies in energy efficiency retrofitting can reduce energy use by up to 40 percent per home and lower total associated greenhouse gas emissions by up to 160 million metric tons annually.

WHITEHOUSE: THE WHITE HOUSE

By comparing the number of graduates from accredited teacher-training programmes with the total number in the teaching workforce in public primary schools, it is possible to assess the efficiency of education systems to train teachers while attempting to meet the rising demand for teachers.

UNESCO: MEDIA SERVICES