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However, Vaccaro and Barnett have shown that an energy cost can be fully avoided by using a reservoir based on something other than energy, such as spin angular momentum. Subatomic particles have spin angular momentum, a quantity that, like energy, must be conserved. Basically, instead of heat being exchanged between a qubit and thermal reservoir, discrete quanta of angular momentum are exchanged between a qubit and spin reservoir. The scientists described how repeated logic operations between the qubit’s spin and a secondary spin in the zero state eventually result in both spins reaching the logical zero state. Most importantly, the scientists showed that the cost of erasing the qubit’s memory is given in terms of the quantity defining the logic states, which in this case is spin angular momentum and not energy.

The results could also apply to hypothetical Carnot heat engines, which operate at maximum efficiency. If these engines use angular momentum reservoirs instead of thermal reservoirs, they could generate angular momentum effort instead of mechanical work.

Reversible computing is a model of computing where the computational process to some extent is reversible, i.e., time-invertible. A necessary condition for reversibility of a computational model is that the relation of the mapping states of transition functions to their successors should at all times be one-to-one. Reversible computing is generally considered an unconventional form of computing.

Landauer's Principle describes the Landauer limit, which is the minimum possible amount of energy required to change one bit of information, as follows:

The Change.org petition was not responsible for attracting national media attention to the case, but I might argue that it helped sustain the story online. The petition gave news consumers a place to act on the sense of injustice the story stoked within them. It also gave celebrities a reason to tweet about the story. Almost half of the 5 million visits to the Change.org petition over this time period were referred by social media.

Given the scale of social media traffic, it's entirely possible that having an action to link to actually increased the rates of people sharing the story online. It's hard to measure the conversation independent of mainstream media coverage, but Pew's Research Center for Excellence in Journalism has found that, as Trayvon Martin became the number one topic discussed on Twitter between March 26-30, "calls for justice (21% of the conversation) and sympathy for the victim (19%) were the top themes on Twitter," both sentiments that lend themselves to including a link to take action.

We can measure conversion rate. Thirty-seven percent of the peop

Here’s how it works: An AmEx cardholder can sign in with Twitter to sync her account — a must-complete first step for savings. The customer is then eligible to tweet any of the current hashtag offers to receive savings that are automatically applied with each eligible purchase. No coupon, print or otherwise, is required.

Should you tweet with the “#AmexWholeFoods” hashtag, for instance, you’d get $20 back on your next trip to Whole Foods, as long as you spend $75 or more at the high-end grocery store before April 30.

This is a question about the future of capitalism, the economic system that arose from scarcity. Ours is the era of expanded copyright systems and enormous portfolios of dubious patents, of trade secrecy, the privatisation of the fruits of publicly funded research, and other phenomena that we collectively term "intellectual property". As technology has made a new abundance of knowledge possible, politicians, lawyers, corporations and university administrations have become more and more determined to preserve its scarcity.

Take the open access movement, which has campaigned to ensure that scientific articles are freely available to the public, who ultimately paid for the research with their taxes. Historically, most scientific writing was confined to expensive scholarly journals and essentially available only to people with university affiliations. Some publishers resisted the open access movement, but trends are against them. In March this year, for example, the US Congress made permanent a requirement that all research funded by the National Institutes of Health be openly accessible, and other countries are following. Within a decade or two, it is safe to say that all scientific literature will be online, free and searchable. Journal publishers will still be paid, but at a different point in the chain.

• Today Cisco announced the results of the Cisco® Visual Networking Index (VNI) Forecast and Methodology, 2008-2013 that confirms consumer broadband usage and global IP network traffic continues to climb at an overwhelming pace due to new forms and expanded usage of interactive media, and the explosion of video content across multiple devices. The study projects that global IP traffic will increase fivefold by 2013. There are key consumer and service provider implications to the forecast that compares regions around the globe including North America, Western Europe, AsiaPac, Middle East and more.

• Global IP traffic is expected to increase fivefold from 2008 to 2013, approaching 56 exabytes per month in 2013, up from approximately 9 exabytes per month in 2008.

In engineering terms, it is easy to see qualitative similarities between the human brain and the internet's complex network of nodes, as they both hold, process, recall and transmit information. "The internet behaves a fair bit like a mind," says Ben Goertzel, chair of the Artificial General Intelligence Research Institute, an organisation inevitably based in cyberspace. "It might already have a degree of consciousness".

The internet's network structure is similar to that of the human brain (Image: ImageSource / Getty)