Science news digest – 30th April 2013
In the science news this week, a HIV vaccine study is stopped in the US, a voice- activated internet system, an urgent call to clear up space debris, and finally… world’s longest running lab experiment is about ready to drop.
Large HIV vaccine study is halted in US
The US government has halted a large HIV vaccine study last week after initial findings revealed that the vaccinations weren’t successful in preventing infection, reported the Guardian.
The shots also failed to reduce the amount of Aids virus in the blood of people who had been vaccinated and then became infected.
The study involved 2,504 volunteers in 19 cities in the US, and was started in 2009. Half of the participants received placebo shots, while the other half received a two-part vaccine that was developed by the National Institutes of Health (NIH).
All of the participants were given free condoms and extensive counselling on the risks of HIV and Aids.
The vaccine is what is known as a “prime-boost” – a DNA based vaccine made with genetically engineered HIV material which is designed to prime the immune system to attack the virus. Then a different vaccine was given which contains the same material inside a shell made of disabled cold virus, to act as a booster shot to strengthen the response of the vaccine.
The hope was that the vaccine would “train” the T cells in the body’s immune system to attack the very early HIV-infected cells in the body. The idea was that the vaccine would either prevent HIV infection, or at least help those who were already infected to fight it.
However, a safety review has revealed that actually slightly more of the study participants who did receive the vaccine became infected with HIV compared to the group who got the placebo.
It’s not clear why this happened, the difference isn’t large enough to be statistically significant, so could be down to chance.
Overall, there were 41 HIV infections in the vaccinated group and 30 among the control group. However, of the participants who were diagnosed after being in the study for at least 28 weeks, there were 27 HIV infections in the vaccinated group and 21 among the placebo group.
Last week, the NIH said that it would be stopping any further vaccinations in the study, known as HVTN 505, but that the researchers would continue to monitor the volunteers’ health.
"It's disappointing," said Dr Anthony Fauci, head of NIH's National Institute of Allergy and Infectious Diseases. But he said that the study had still allowed for "important information" to be gained about what to try next.
Voice-based internet system helps illiterate get online
A new voice-based web system could help make it easier for illiterate people to browse the internet. The project, which is sponsored by the European Commission, is called Voices and has been set up in Mali as a way to build an information system for farmers and as a platform for citizen journalism.
"The need for knowledge-sharing is universal, not just intrinsic to us in the West," says Anna Bon of VU University in Amsterdam, the Netherlands, one of the project's 14 partners.
The system is based on VoiceXML, a programming language that lets users vocally control specially created web content. Malians can navigate the content by listening to options and then pressing buttons on their phone, reported New Scientist.
Late last year, the system was used by global news network Al Jazeera to get vox pops from some rural communities during the election campaigns in Ghana and Kenya.
Working with Safaricom and Voices, Al Jazeera built a platform where people could call in using a cellphone to contribute their thoughts on the elections, and also to listen to updates from the website.
“We were trying to plug into communities that you didn't hear that much from," says Cynara Vetch, who manages the service for Al Jazeera. "You suddenly get this plethora of voices giving you this wide array of angles."
But it’s not just journalism that could benefit from the system. It could also allow remote villagers to promote the produce they have available and to find a buyer for it.
An older system that used text messages sent by a village representative enabled one farmer go from having a few dozen bee hives to a thousand after he found a market for his honey in a nearby town, for example.
This new system would allow even greater access as it wouldn’t rely on having one representative for each village to send the messages.
Space debris urgently needs to be removed
There is now a hazardous amount of debris in the space environment around the Earth, a major international meeting concluded last week.
Scientists estimate that there are nearly 30,000 items of space debris that are larger than 10cm in size orbiting the Earth. There is now an “urgent need” to remove the redundant objects from space the meeting summarised.
The objects range from whole satellites to smaller fragments that have broken off from previous collisions in space, reported the BBC.
Anything larger than 10cm can be tracked by radar, but there are tens of thousands of smaller pieces that move around completely unseen.
However, it is now the prospect of an increase in catastrophic collisions that worries the experts.
"There is a consensus among debris researchers that the present orbit debris-environment is at the rim of becoming unstable within a few decades, a phenomenon that is commonly known as the Kessler Syndrome, and that only active removal of five to 10 large objects per year can reverse the debris growth," Prof Heiner Klinkrad, the head of the European Space Agency's (Esa) Space Debris Office and chair of the Sixth European Conference on Space Debris held in Darmstadt, Germany last week.
A study presented earlier in the week called for better adherence to best practice guidelines on the use of low-Earth orbits (LEO) – the important altitude where imaging spacecraft reside.
The guidelines urge space operators at LEO to ensure their equipment naturally falls back to Earth within 25 years of the end of a mission.
However, this has not been the case with many of the redundant objects in this orbit, and the panel now believe the best way to solve the problem is to actively remove some of the larger objects.
What is not clear is how much time there is before the situation becomes intolerable.
"We say we want to 'stabilise' the environment. Does that mean we are satisfied with today's situation? Could we live with a situation that is two times worse than today, or do we need to decrease [the debris population]? These are questions which are ongoing at international level," said Christophe Bonnal from the French space agency (CNES).
Active removal of the debris would involve launching new spacecraft specifically for that role, and the design of such spacecraft was debated last week at the meeting, with everything from harpoons, tentacles, ion thrusters, lasers and even nets.
The panel have said that it is vital that these new programmes are piloted as soon as possible to advance the technologies.
Excitement is building around the world’s longest running lab experiment
Started in 1927, Queensland University’s pitch drop study is the world’s oldest laboratory experiment, and probably its slowest too.
Since the apparatus was set up in the foyer of the university’s physics building over 80 years ago, there have been only eight drops from the suspended lump of pitch.
However, excitement is now rising, as the experiment looks set to see another drop in the near future, reported the Guardian.
Pitch is the world’s stickiest substance, with a viscosity at least 230 billion times greater than water, and this experiment was originally set up to determine that figure.
Pitch is brittle enough to be smashed with a hammer, but it also behaves like a fluid.
"No one has actually seen a drop emerge, so it is getting quite nervy round here," said Professor John Mainstone, who has run the experiment since the 1960s.
"The other eight drops happened while people had their backs turned. For the last drop, in 2000, we had a webcam trained on the experiment, but it broke down … in 1988, when the previous drop was about to emerge, I popped out for a coffee and missed it."