Science’s Top Ten
Showing a clear departure from the year 2005, the world’s leading scientific research journal Science has dubbed an outstanding work of mathematics as the most significant breakthrough of the year 2006. It is worth mentioning that a work in the field of organic evolution had been accorded the same pride of place in the year 2005 for which the journal had invited criticism from several corners. Taking cognizance of that fact, the Editorial has aptly noted, “Our readers can relax this year; Religion and politics are off the table, and n-dimensional geometry is on instead”.
Solution of A Century-old Mathematical Riddle
The work of Russia’s Publicity shy mathematician Grigori Perelman has topped the Science’s Top Ten Breakthroughs of the Year 2006’. As the Editorial says, “To mathematicians, Grigori Perelman’s proof of the Poincare Conjecture qualifies at least as the Breakthrough of the Decade. But it has taken them a good part of that decade to convince themselves that it was for real”.
Poincare Conjecture, which deals with abstract shapes in three-dimensional space, has finally been solved. The Poincare Conjecture is part of a branch of mathematics called topology, informally known as ‘rubber sheet geometry’ because it involves surfaces that can undergo arbitrary amounts of stretching. Proposed in 1904 by Henri Poincare, the conjecture describes a test for showing that a space is equivalent to a ‘hypersphere’, the three-dimensional surface of a four-dimensional ball.
In 2002, Russian mathematician Grigori Perelman, posted on the Interner the first of three papers that outlined a proof of Poincare`s conjecture as part of an even more ambitious result. Though many lacunae still existed, it appeared that Perelman had indeed solved one of the most difficult problems in mathematics. The year 2006 saw three teams filling in the gaps of Perelman’s proof.
Tracking the Trail Of Neanderthal-Homo Sapien Divergence
The two groups that published their results in 2006 concluded that Neanderthals diverged from our own ancestors at least 4,50,000 years ago- approximately the time suggested by fossil and mitochondrial DNA studies.
While one group decoded 65,000 Neanderthal bases the other decoded a million bases. Together these two groups showed that researchers could now find sequence changes between modern and ancient humans. The works provide us a very rough draft of the complete Neanderthal genome sequence. This discovery coincided with the 150th anniversary of the discovery of the Neanderthal type specimen celebrated in 2006.
Depletion of Great Ice Sheets
While climate change and its effects on ice sheets is now accepted, the observation by glaciologists that the two great ice sheets covering Greenland and Antarctica are melting and losing ice to the oceans proved beyond doubt the effect of climate change. The scientists also showed that the ice sheets are being lost at an accelerating pace.
The observation has in turn brought out the effect of how the sensitive ice sheets react to ‘an as-yet modest warming of air and ocean water”. Both Greenland and Antarctica have been losing ice over the past 5 to 10 years with Greenland shedding at least 100 gigatons each year and Antarctica in the range of tens of gigatons per year or more.
Evolutionary Feat Of a Fossil Fuel Discovery
If glaciologists showed the effect of melting ice sheets on low lying coastal areas, paleontologists dug out evidence of a fossil fish that long ago took a deep breath and made some tentative but ultimately far-reaching steps onto land. “The 375-million-year-old specimen with its sturdy jointed fins fills and evolutionary gap and provides a glimpse of the features that helped later creatures conquer the continents”, Science reports. The fish have been named Tiktaalik roseae for ‘large freshwater fish’ in the Inuktitut language and a donor who helped fund the expedition, respectively.
“All limbed vertebrates, known as tetrapods, evolved from lobe-finned fishes some 370 million to 360 million years ago. The new species is the most tetrapod-like fish yet discovered”.
The First Rudimentary Invisibility Cloak
Physicists also share their own claim for fame in 2006 by cobbling together the first ‘rudimentary invisibility cloak’ – Scientists developed this year the first rudimentary device for shielding objects from view. The device guides incoming microwaves in such a way that they produce neither a reflection nor a shadow. Although far from perfect – the ring shaped cloak is invisible only when viewed in microwaves of a certain wavelength travelling parallel to the plane of the ring – the device could usher in a potentially revolution approach to manipulating electromagnetic waves.
The First Ray Of Hope For AMD Patients
The battle against Age-related Macular Degeneration (AMD), which is one of the leading causes of blindness in people, appears to be won. The results of two clinical trials showed that treatment with the drug ranibizumab improves the vision of roughly one-third of patients with the more serious wet form of AMD and stabilizes the condition of most of the others. Other approved treatments can only slow the progression of AMD.
Vision loss in the wet form of AMD is caused by the growth and leakage of abnormal blood vessels in the macula, the central region of the retina. The drug ranibizumab targets the protein that stimulates the vessel growth.
Detecting Genetic Changes To Develop New Species
How does speciation start? Several genetic changes make a group of individuals become a separate species by giving them the extra advantage to survive in a new environment. And understanding these have come, thanks to genomics, in helping scientists understand one of the most fundamental questions of biology on biodiversity.
From Florida beach mice to cactus finches, the effect of a single gene to help them become, a separate species has been brought out.
Genes can help drive speciation in other ways as well. Researchers have long ago realized that as two incipient species diverge, “the sequences of two or more interacting genes can evolve along different paths until the proteins they encode no longer work together in any crossbred offspring”. Scientists now have been able to pinpoint the first such pair of incompatible genes in Drosophila melanogaster and a sister species, D. simulan.
“In June, evolutionary biologists detailed the most convincing case yet of a species that arose through hybridization. They bred two species of passion vine butterflies and got the red and yellow stripe pattern of a third species”.
New Insight into Cellular Structure
Biologists have for the first time managed to get a clearer view of the fine structure of cells and proteins. This was possible as they used a microscopy technique that sidestepped a fundamental limit of optics – inability to study features smaller than half the wavelength of the light used to illuminate an object – about 200 nanometres for visible light.
Researchers in Germany using a technique known as Stimulated Emission Depletion (STED) and another simpler technique known as photoactivated localization microscopy (PALM) have used fluorescent dye/tag effectively with some light manipulations to study biological specimens that was not possible using conventional optical techniques.
Verification of Brain’s Memory Retention Capability
How does the brain record new memories? A process called Long Term Potentiation (LTP) that strengthens connections between neurons was long suspected by neurologists to be the answer but there was no way of proving it.
Several findings reported in 2006 strongly bolstered the case. “LTP is based on the fact that synaptic connections between neurons in the hippocampus, a brain region tied to memory, are bolstered under certain conditions”.
Scientists discovered LTP is the early 1970s, when experiments with rabbits showed that a brief barrage of electrical zaps could holster synaptic connections between neurons in the hippocampus, a brain region tied to memory.
Observing LTP in the hippocampus when an animal learns something was essential to prove LTP. In January, Spanish scientists reported such an observation in mice conditioned to blink upon hearing a tone. In August, another research team described LTP in the hippocampus of rats that had learned to avoid an area where they had previously received a shock.
Discovery of A New RNA Type
After DNA, it has been the turn of small RNA molecules to hog the limelight. The number of small RNA being discovered seems unending with Piwi-interacting RNAs (piRNAs) joining the elite club. piRNAs made their grand entrance last summer.
piRNAs are abundant in the rests of several animals, including humans and are distinctly different from their small RNA cousins. They appear to regulate the development and maintenance of sperm cells in many species. But much is unknown about them.
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