Year: 2014

BATH (TIP): Some of the US navy’s futuristic weapons sound like something out of ‘Star Wars’, with lasers meant to shoot down drones and electric guns that fire projectiles at hypersonic speeds. That future is now. The navy plans to deploy its first laser on a ship later this year, and it aims to test an electromagnetic rail gun prototype on a vessel in two years.

For the US navy, it’s not so much about the whiz-bang technology as it is about the economics of such weapons. Both costs pennies on the dollar compared with missiles and smart bombs, and the weapons can be fired continuously, unlike missiles and bombs, which eventually run out. “It changes the way we fight,” said Captain Mike Ziv, programme manager for directed energy and electric weapon systems for the Naval Sea Systems Command.

The technology has evolved to the point that a prototype to be deployed on the USS Ponce this summer can be operated by a single sailor. The solid-state laser weapon system is designed to target what the US navy describes as “asymmetrical threats”. Those include drones, speed boats and swarm boats, all potential threats to warships in the Persian Gulf, where the Ponce is set to be deployed.

Rail guns, which have been tested on land in Virginia, fire a projectile at six or seven times the speed of sound — enough velocity to cause severe damage. The US navy sees them as replacing or supplementing oldschool guns, firing lethal projectiles from long distances. However, both systems have shortcomings. Lasers lose their effectiveness if it’s raining, if it’s dusty or if there’s turbulence in the atmosphere, and the rail gun needs vast amount of electricity, said Loren Thompson, defence analyst at Lexington Institute.

LONDON (TIP): A puzzle that has confounded mathematicians for almost a century is closer than ever to being solved, it has emerged. But there’s one slight problem. The calculations which prove a part of what’s known as “Erdos discrepancy problem” have been worked out by a computer. And the amount of data — more than the entire contents of Wikipedia — is so vast that it would be practically impossible to be checked by a human brain.

The “discrepancy problem” was posed in the 1930s by mathematician Paul Erdos. It revolves around properties of infinite sequences of numbers containing only +1s and -1 s. Patterns in such sequences can be measured by creating finite sub-sequences . Enrico Scalas of University of Sussex explained the premise : “You have a sequence of 1s and -1 s (for instance, generated by tossing a coin) and a constant C. One is looking for a finite subsequence long enough so that sum of elements of the sub-sequence is larger than C.”

The difficulty lies in proving this. That’s where the ability of computers to perform complex calculations comes in. With this aid, Alexei Lisitsa and Boris Konev of the University of Liverpool showed that an infinite sequence will have a discrepancy (the sum of the numbers in a sub-sequence ) larger than two.

They took a sequence 1,161 numbers long and the resulting data was a 13GB file. That’s bigger than the estimated 10GB size of Wikipedia’s written contents. It is the start of solving the puzzle – but while computers have helped, they have not yet taken over from humans. Mathematicians were philosophical about being beaten by a machine. Matt Parker, public engagement in maths fellow at Queen Mary University of London, said: “The computer did the heavylifting , but it was the insight and creativity of its human programmers which made it possible.”

LONDON (TIP): All is not lost for the fastdisappearing Aral Sea, a saline lake in central Asia. Nasa satellites have discovered large amounts of water – almost half of its capacity – hidden in the central part of the watershed, raising hopes of reviving what was once the fourth largest itit in the worldit.

The Aral Sea It has lost 90% of its water volume in the last 50 years. The new data says although the long-term water picture for the Aral Sea watershed in Central Asia is bleak, short-term prospects are better than previously thought. Its watershed – the enormous closed basin around the sea – encompasses Uzbekistan and parts of Tajikistan, Turkmenistan, Kyrgyzstan and Kazakhstan. Kirk Zmijewski and Richard Becker of the University of Toledo, Ohio, wanted to find out whether all of the water was gone for good, or whether some of it might have ended up elsewhere in the watershed, behind dams or in aquifers.

They also wanted to gauge whether decreasing rainfall had contributed to the catastrophic water loss. The researchers used data from Nasa’s Gravity Recovery and Climate Experiment satellites to map monthly changes in mass within the watershed from 2003 to 2012. They mapped the entire Aral Sea watershed and found that each year throughout the decade, the watershed lost an average of 4.6 to 5.4 cubic miles of water or the equivalent of one Lake Mead per year – only about half as much as the rate at which the Aral Sea itself is losing water (5.8 cubic miles or 24 cubic kilometers).

“That means that roughly half the water lost from the Aral Sea has entirely left the watershed, by evaporation or agricultural uses, but half is upstream within the watershed,” said Becker. Decreasing rainfall in the region has been widely reported, and the researchers wanted to quantify its role in the water loss.Unexpectedly, they also found no change in precipitation since 2002.

WASHINGTON (TIP): Scientists have found out why physicist Albert Einstein, who for long believed that the universe was static, changed his mind and accepted the modern cosmological view that the cosmos is expanding. Until 1931, the 20th century genius, Einstein believed that the universe was static rather than expanding.

An urban legend attributes this change of perspective to when American astronomer Edwin Hubble showed Einstein his observations of red shift in the light emitted by far-away nebulae – today known as galaxies. But the reality is more complex, researchers said. The change in Einstein’s viewpoint, in fact, resulted from a tortuous thought process, said researchers in an article published in the European Physical Journal H. Harry Nussbaumer from the Institute of Astronomy at ETH Zurich, Switzerland, explained how Einstein changed his mind following many encounters with some of the most influential astrophysicists of his generation.

In 1917 Einstein applied his theory of general relativity to the universe, and suggested a model of a homogenous, static, spatially curved universe. However, this interpretation has one major problem: If gravitation was the only active force, his universe would collapse – an issue Einstein then addressed by introducing the cosmological constant. He then fiercely resisted the view that the universe was expanding, despite his contemporaries’ suggestions that this was the case.

For example, in 1922, Russian physicist Alexander Friedman showed that Einstein’s equations were viable for dynamical worlds. For instance, in 1927, Georges Lemaitre, a Belgian astrophysicist from the Catholic University of Louvain, concluded that the universe was expanding by combining general relativity with astronomical observations. Yet, Einstein refused to abandon his static universe. However, in an April 1931 report to the Prussian Academy of Sciences, Einstein finally adopted a model of an expanding universe. In 1932, he teamed up with the Dutch theoretical physicist and astronomer, Willem de Sitter, to propose an eternally expanding universe which became the cosmological model generally accepted until the middle of the 1990s.

NEW YORK (TIP): Scientists have found a new way to clean the remaining human immunodeficiency virus (HIV) from the bodies of infected patients after they have been treated with antiretroviral therapy.

Scientists used radioimmunotherapy (RIT) to destroy remaining human immunodeficiency virus (HIV)-infected cells in the blood samples of patients treated with antiretroviral therapy, offering the promise of a strategy for curing HIV infection. Ekaterina Dadachova from Albert Einstein College of Medicine in the Bronx, New York and a team of researchers administered RIT to blood samples from 15 HIV patients treated with highly active antiretroviral therapy (HAART).

RIT, which has historically been employed to treat cancer, uses monoclonal antibodies – cloned cells that are recruited by the immune system to identify and neutralise antigens. “In RIT, the antibodies bind to the infected cells and kill them by radiation. When HAART and RIT are used together, they kill the virus and the infected cells, respectively,” said Dadachova, the study’s lead author.

Dadachova’s team paired the monoclonal antibody (mAb2556) designed to target a protein expressed on the surface of HIV-infected cells with the radionuclide Bismuth-213. Researchers found that RIT was able to kill HIV-infected lymphocytes previously treated with HAART, reducing the HIV infection in the blood samples to undetectable levels.

“The elimination of HIV-infected cells with RIT was profound and specific. The radionuclide we used delivered radiation only to HIVinfected cells without damaging nearby cells,” Dadachova said. An important part of the study tested the ability of the radiolabeled antibody to reach HIV-infected cells in the brain and central nervous system. Using an in vitro human blood brain barrier model, the researchers demonstrated that radiolabeled mAb2556 could cross the blood brain barrier and kill HIV-infected cells without any overt damage to the barrier itself.