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Google moves closer to 'real-time'search

You can now literally get up-to-the-minute search results from Google, which includes web pages updated as little as 10 seconds before you click onto them.

Google does not necessarily index web pages as soon as they are published, but sites containing feeds and sitemaps are among the quickest to be listed.

The news of the faster-updating Google was released on the unofficial Google news website.

It announced that Google’s date range restrictions had been extended, allowing users to find web pages indexed by Google less than one minute ago, or even less than 10 seconds ago.

With recent advancements such as PubSubHubbub, a forum for web publishers which provides real-time notifications for updates, the delay between publishing pages and finding them using Google will be further reduced.

To locate the most up-to-date pages, click on “show options”, select “past 24 hours” and tweak the URL by replacing “tbs=qdr:d” with “tbs=qdr:n” to find pages indexed in the past minute.

The date restriction feature is quite flexible, but you need to know the syntax used by Google’s URLs:

tbs=qdr:[name][value]

where [name] can be one of these values: s (second), n (minute), h (hour), d (day), w (week), m (month), y (year), while [value] is a number.

To find the web pages indexed less than 45 seconds ago that include the word “flu”, use this URL:

http://www.google.com/search?q=flu&tbs=qdr:s45

Unfortunately, if you restrict the results to very recent web pages, Google shows a small sample and doesn’t list all the results.

So while this should help anyone looking for information on, say, a news story of the day, it may not be quite so effective on stories as they break.

Google’s algorithm for ranking web pages could play a valuable role in sustaining the earth’s ecosystems, by allowing biologists to map eco-systems.

Researchers in America are adapting Google PageRank – the formula by which the giant search engine monitors the internet and catalogues its indices – so that it can map out the complex relationships involved in these eco-systems, and determine which species are essential to sustain individual eco-systems.

Food webs are the complex networks of who eats whom in an ecosystem. And Dr Stefano Allesina of the National Centre for Ecological Analysis and Synthesis says their version of PageRank – outlined in their paper ‘Googling food webs: can an eigenvector measure species’ importance? could be a simple way of working out which extinctions would lead to ecosystem collapse.

Every species is embedded in a complex network of relationships with others. So a single extinction can cascade into the loss of seemingly unrelated species.

Investigating when this might happen using more conventional methods is complicated as, even in simple ecosystems, the number of combinations exceeds the number of atoms in the universe. So it would be impossible to try them all.

Co-author Dr Stefano Allesina realised he could apply PageRank to the problem when he stumbled across an article in a journal of applied mathematics describing the Google algorithm.

The researchers say they had to make minor changes to it to adapt it for ecology.

Dr Allesina, of the University of Chicago’s department of ecology and evolution, told BBC News: “First of all we had to reverse the definition of the algorithm.

“In PageRank, a web page is important if important pages point to it. In our approach a species is important if it points to important species.”

They also had to design in a cyclical element into the food web system in order to make it applicable to the algorithm.

They did this by including what Dr Allesina terms the “detritus pool”. He said: “When an organism dies it goes into the detritus pool and in turn gets cycled back into the food web through the primary producers, the plants.

“Each species points to the detritus and the detritus points only to the plants. This makes the web circular and therefore leads to the application of the algorithm.”

Dr Allesina and co-author Dr Mercedes Pascual of University of Michigan have tested their method against published food webs, using it to rank species according to the damage they would cause if they were removed from the ecosystem.

They also tested algorithms already in use in computational biology to find a solution to the same problem.

They found that PageRank gave them exactly the same solution as these much more complicated algorithms.

Dr Glyn Davies, director of programmes at WWF-UK, welcomed the work. He said: “As the rate of species extinction increases, conservation organisations strive to build political support for maintaining healthy and productive ecosystems which hold a full complement of species.

“Any research that strengthens our understanding of the complex web of ecological processes that bind us all is welcome.”