The study was done from November 1993 to December 2000. The researchers analysed records from the ambulance unit at the Charles de Gaulle airport in France, which showed that nearly 135 million passengers had arrived during that time. Fifty-six of these required the airport ambulance because of pulmonary embolism.
The incidence of pulmonary embolism was much higher among passengers travelling more than 5000 km - 1.5 cases per million, as compared with 0.01 case per million among those travelling less than 5000 km. The incidence of pulmonary embolism rose to 4.8 cases per million for those travelling more than 10,000 km.
The vast majority of the patients said that they had not moved during the flight. However the risk of embolism rose significantly in people travelling a greater distance. It was established that the farther people fly, the more likely they are to suffer a potentially fatal blood clot in their lungs. This study underlines the importance of in-flight exercises to maintain the blood circulation and prevent embolism.
विज्ञान की शोध पत्र नेचर केमिकल बायलॉजी में प्रकाशित शोध के अनुसार ब्रिटेन और अमरीका के वैज्ञानिकों ने टीबी बैक्टीरिया के एक ऐसे रसायन का पता लगाया है जो टीबी बैक्टीरिया को स्वंय समाप्त कर देगा.
लेकिन बीबीसी संवाददाता का कहना है कि ये देखना होगा कि अंतरराष्ट्रीय दवा कंपनियाँ इस ओर कितना ध्यान देती हैं क्योंकि शोध की ये प्रक्रिया काफ़ी लंबी है.
ग़ौरतलब है कि टीबी के कारण विश्व में हर साल लाखों लोगों की मौत हो जाती है.
शोधकर्ता इस बीमारी के ऐसे बैक्टीरिया के सामने आने से चिंतित हैं जिन पर दवाओं का असर नहीं होता.
विश्व स्वास्थ्य संगठन के अनुमान के मुताबिक एमडीआर टीबी यानी मल्टी ड्रग रिज़िसटेंट टीबी के लाखों मामले हर साल सामने आते हैं.
इनमें से ज़्यादातर मामले भारत, चीन और पूर्व सोवियत संघ से होते हैं.
मल्टी ड्रग रिज़िसटेंट टीबी बीमारी का वो रूप है जिसमें कम से कम दो मुख्य तरह की टीबी पर दवाओं का असर नहीं होता है.
इस तरह की टीबी के लिए अलग किस्म की दवाओं का इस्तेमाल करना पड़ता है.
ये दवाएँ ज़्यादा नुक़सानदेह और मंहगी होती हैं और साथ ही ठीक होने में समय भी ज़्यादा लगता है.
उल्लेखनीय है कि टीबी की रोकथाम करने वाली मौजूदा दवा सौ फीसदी प्रभावी नहीं है और इसका इस्तेमाल भी लगातार कम से कम छह महीने करना पड़ता है.
इसका मतलब यह है कि बहुत से लोग अगर इस कोर्स को पूरा नहीं करते तो इस रोग का आक्रमण फिर से होने का ख़तरा बना रहता है.
Average citizens are using the Internet and mobile phones to fight violence, and the movement is set to grow. That was the message of a two-day London summit in which social media activists from around the world met to explore ways the Internet and mobile technology tools can be used to combat violent extremism.
Jason Leibman, Co-founder of the Alliance for Youth Movement, which organized the event, says Web sites such as the social networking site Facebook, the video-sharing site YouTube, and the micro-blogging site Twitter have become critical tools for fighting extremism.
But he says extremist groups are also often savvy Internet users. "Groups like al-Qaida are extraordinarily sophisticated in how they're using media, which is everything from setting up popular blogs, being on platforms like YouTube, using platforms like Second Life really effectively - so the quote unquote 'bad guys' are often extraordinarily effective at using these tools - much more effective than those that are trying to fight against them," he said.
Social media, he says, is a natural extension of traditional media sources such as radio and television. But he says by using the Internet people can get global attention for their cause cheaply and easily.
And he says all over the world people are using the Internet to fight what they see as injustices. He says, for example, that the micro-blogging site Twitter has been used to combat media censorship in Iran. "You know, one of the reasons it's been so widely used in Iran is that it's a great tool for people that are being blocked off often times from media coverage, from the Internet even, to get up and broadcast their messages to the world," he said.
Colombian Oscar Morales Guevara set up a Facebook group in January 2008 against the insurgent group Revolutionary Armed Forces of Columbia. Morales called for a massive march against the guerilla organization, and through Facebook rallied over 12 million people who marched in over 200 cities around the world.
Its supporters included Colombia's president, Alvaro Uribe and the country's most influential newspaper El Tiempo - but Morales says the movement was not led by politics. "We had no engagement whatsoever with any political parties, we were just regular citizens expressing ourselves, demanding that our voice be heard," he said.
He says the Internet has given people the power to be independent. "One of the things that Internet has is that we can have our own voice, our own movement, without having to rely on governments, or on traditional media. Facebook itself is a media," he said.
Pastor Kingsley Bangwell, from the Nigeria-based Youngstars Foundation, which gets young people involved in social development projects in Africa, says right now the use of Internet is not sufficiently widespread in Africa to be as useful a tool.
But mobile phones, he says, are changing lives. According to the United Nations, mobile subscriptions in Africa rose from 54 million to almost 350 million between 2003 and 2008, the quickest growth in the world.
And, Kingsley says, mobile phones are used for everything from sending money to buying food in a market.
And he says they're increasingly used by young people for political purposes. He says young people in Nigeria are using their phones to raise awareness about the next election. "Right now as we're talking young people are mobilizing, gathering phone numbers because they want to engage in huge text message mass campaign and all of that, so it's also going to play a very critical role in the forthcoming election. I'm hearing that is happening also in Ghana, I'm hearing that Cameroon is mobilizing around that -- people are beginning to understand the power of using telecoms for campaigns," he said.
According to Internet marketing research firm Miniwatts Group, there are about 1.7 billion Internet users worldwide. In Africa it says there are 67 million, up from only 4.5 million users in 2000.
The development of invisible cloaks are many years away from becoming a reality, but some researchers in Germany are working in a new field that could also lead to more powerful microscopes and harness light to make electricity.
The field is called transformation optics. Researchers are using nanotechnology, in which they create extremely small items from metal, electrons and semiconductors, to bend light from all distances and in many different directions so it becomes invisible to the naked eye.
German researchers Karlsruhe Institute of Technology demonstrated the potential to hide objects from detection by bending light in three dimensions to conceal a small bump on a gold surface that, like a carpet, overlaid a nanostructure made up of particles like a pile of wood. The gold surface also became invisible in nearly visible infrared light.
Vladimir Shalaev is a professor of electrical and computer engineering at Purdue University in Indiana. He says light travels along a single path from one point to another. But transformation optics, according to Shalaev, bends light around objects like water around a rock in a stream.
"What we are trying to do is to bend it, to turn it around the corner, to get sucked in certain area[s] that's just been excluded from certain area[s] that's the idea behind cloaking," said Vladimir Shalaev.
Shalaev says transformation optics could also someday be used to create very powerful microscopes, ten times more powerful than an electron microscope, by focusing it in a particular area, and converting sunlight into electricity.
"When you concentrate it in an extremely small area and that could be just for a very efficient conversion of light into electricity, that's photovoltaics," he said. "And since people are now so keen in energy, that could be a very efficient way to instantly convert light energy into electrical energy."
German scientists say it would take a long time to scale up the technology to completely hide an object although such techniques could be developed in the future.
Until now, cloaks have been developed to conceal objects in two dimensions, but they create a shadow that can be detected with instruments.
This is the first time researchers have hidden an object in three dimensions, according to Purdue University Vladimir Shalaev, who marvels at the accomplishment.
"Their structure is just beautiful in terms of the fabrication," said Shalaev. "It's just spectacularly nice."
The study on transformation optics and its potential uses were published this week in the journal Science.
The Large Hadron Collider, the world's biggest physics experiment, has broken its own particle beam energy record.
On Friday morning, the machine created two beams of protons, each with an energy of 3.5 trillion electron volts. The effort breaks the prior record, set by the LHC in December, of just over a trillion electron volts in each beam.
The LHC will now aim to smash those two beams together, hoping to create new particles that give insight into the most fundamental workings of physics.
The experiment, housed in a 27km-long tunnel under the outskirts of Geneva in Switzerland, has only been back online since November 2009.
A breakdown and helium leak in 2008, shortly after the machine was first switched on, took some 14 months to repair.
"Getting the beams to 3.5 TeV is testimony to the soundness of the LHC's overall design, and the improvements we've made since the breakdown in September 2008," said Steve Myers, director for accelerators and technology at the Swiss laboratory Cern, where the LHC is based.
 The LHC's experiments create showers of particles |
Since coming back online, the machine has exhibited performance that was "remarkable", according to Cern director general Rolf Heuer.
In an announcement of the 3.5 TeV result, he congratulated the LHC team and stressed the cutting-edge nature of its work.
"We must not lose sight of the fact that the LHC is new, and it wasn't bought off the shelf," he wrote.
As with all particle accelerators, the LHC will be periodically shut down for maintenance, but LHC officials recently decided to significantly lengthen the shutdown period.
This is in part because the machine takes so long to reach and return from the low temperatures required for its experiments.
But the shutdown scheduled for late 2010 will also address the joints between the machine's superconducting magnets, which must be strengthened before the LHC can run at even higher energies.
"It is a state of the art prototype that is pushing the limits of technology across a wide range of disciplines, and as such it needs to be treated with the greatest respect," Professor Heuer wrote.
"It takes time, but as we've seen this week, patience pays dividends."