World's Fastest Supercomputer' Crowned in US

'World's Fastest Supercomputer' Crowned in US - In the clash of the world's supercomputing titans, a new U.S. supercomputer named "Titan" is king.

The $100-million Titan seized the No. 1 supercomputer ranking on the Top500 List with a performance record of 17.59 petaflops per second (quadrillions of calculations per second). The supercomputer, a Cray XK7 system based at Tennessee's Oak Ridge National Laboratory, leaped past the former champion, the Sequoia supercomputer at California's Lawrence Livermore National Laboratory.

 

The Titan supercomputer at Oak Ridge National Laboratory was crowned the fastest in the world just a few weeks after its debut.

The top five supercomputers in the world are:

1. Titan Cray XK47 at Oak Ridge National Laboratory (17.59 petaflops/s)
2. Sequoia BlueGene/Q at Lawrence Livermore National Laboratory (16.33 petaflops/s)
3. Fujitsu's K computer at the RIKEN Advanced Institute for Computational Science in Kobe, Japan (10.51 petaflops/s)
4. The Mira BlueGene/Q computer at Argonne National Laboratory in Lemont, Ill. (8.16 petaflops/s)
5. The JUQUEEN BlueGene/Q computer at the Forschungszentrum Juelich in Germany. (4.14 petaflops/s)

U.S. supercomputers had fallen behind China's Tianhe-1A supercomputer and Japan's Fujitsu K Computer starting in 2009, but staged a comeback with Sequoia's rise in 2012.

Sequoia's 1,572,864 computing cores actually outnumber Titan's 560,640 cores, but not all computing cores are created equal. Titan draws 90 percent of its performance from having 261,632 of NVIDIA's new K20x accelerator cores.

The NVIDIA accelerator cores use the same graphics processing unit (GPU) technology that drives graphics cards for displaying video games. GPUs run tasks on many different "threads" that may run slower than traditional threads on central processing units (CPUs), but GPUs make up for that by running many more threads simultaneously.

GPU-driven supercomputers will become even more crucial in building the next generation of "exascale" supercomputers that would work 1,000 times faster than today's supercomputers. That's because GPUs use far less energy than the CPUs that have traditionally driven computing.

Titan used the new Tesla K20x accelerators to achieve an energy efficiency of 2,142.77 megaflops per watt (million calculations per second per watt), enough to also rank Titan No. 1 on the Green500 list of the world's most energy-efficient supercomputers. ( LiveScience.com )

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Obesity Gene May Shield Against Depression

Obesity Gene May Shield Against Depression — Perhaps there is a bit of truth to the stereotype about being fat and happy — new research finds that people who have a gene linked with obesity may have a slightly lower risk of depression.

People who had a version of a gene called the FTO gene were 8 percent less likely to have depression, researchers found. In 2007, scientists discovered this version of the FTO gene was a major contributor to genetic obesity among people of European descent.

The finding "suggests that the FTO gene may have a broader role than initially thought, with an effect on depression and other common psychiatric disorders," the researchers wrote in their study published today (Nov. 20) in the journal Molecular Psychiatry.

The researchers said the findings challenge the idea that obesity and depression are generally linked. Some have suggested that obese people become depressed because of their appearance and discrimination, while people with depression may become less active and change their eating habits to cope with their illness.

"The difference of 8 percent is modest, and it won't make a big difference in the day-to-day care of patients," study researcher David Meyre, associate professor in clinical epidemiology and biostatistics at McMaster University in Canada, said in a statement. "But, we have discovered a novel molecular basis for depression," Meyre said.

The researchers looked at data gathered on more than 17,000 people who participated in a genetics study between 2001 and 2003. About 3,200 of the participants had depression. The researchers further supported the link they found by analyzing data on genes of patients in three additional large international studies.

Still, further studies are needed to confirm the findings, they said.

Previous studies of families have suggested that 40 percent of the risk of depression comes from genetics, the researchers said. However, attempts to find specific genes associated with depression have not produced convincing evidence so far, according to the study.

This finding is important because about 9 percent of U.S. adults have depression at any given time, according to estimates from the Centers for Disease Control and Prevention.

Pass it on: A gene linked with obesity may help protect people against depression. ( LiveScience.com )

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We mated with Neanderthals. Can we breed with other animals, too?

We mated with Neanderthals. Can we breed with other animals, too? - Last week, scientists announced that the human gene pool seems to include DNA from Neanderthals. That suggests that humans interbred with their primate cousins at some point before the Neanderthals went extinct about 30,000 years ago. Could we mate with other animals today?

Probably not. Ethical considerations preclude definitive research on the subject, but it's safe to say that human DNA has become so different from that of other animals that interbreeding would likely be impossible. Groups of organisms tend to drift apart genetically when they get separated by geographical barriers—one might leave to find new food sources, or an earthquake could force them apart. When the two groups come back into contact with each other many, many years later, they may each have evolved to the point where they can no longer mate.

In general, two types of changes prevent animals from interbreeding. The first includes all those factors—called "pre-zygotic reproductive isolating mechanisms"—that would make fertilization impossible. After so many generations apart, a pair of animals might look so different from one another that they're not inclined to have sex. (If we're not even trying to mate with monkeys, we'll never have half-human, half-monkey babies. *) If the animals do try to get it on despite changed appearances, incompatible genitalia or sperm motility could pose another problem: A human spermatozoon may not be equipped to navigate the reproductive tract of a chimpanzee, for example.

The second type of barrier includes "post-zygotic reproductive isolating mechanisms," or those factors that would make it impossible for a hybrid animal fetus to grow into a reproductive adult. If a human were indeed inclined and able to impregnate a monkey, post-zygotic mechanisms might result in a miscarriage or sterile offspring. The further apart two animals are in genetic terms, the less likely they are to produce viable offspring. At this point, humans seem to have been separate from other animals for far too long to interbreed. We diverged from our closest extant relative, the chimpanzee, as many as 7 million years ago. (For comparison, our apparent tryst with the Neanderthals occurred less than 700,000 years after we split off from them.)

Researchers haven't pinned down exactly which mechanisms prevent interbreeding under most circumstances. Some closely related species can mate even if they have different numbers of chromosomes. Przewalski's horse, for example, has 33 pairs of chromosomes instead of the 32 most horses have, but it can interbreed with regular equines anyway—the offspring takes the average and ends up with 65 chromosomes.

Neanderthals weren't our ancestors' only dalliance with other primates. "Pre-humans" and "pre-chimpanzees" interbred and gave birth to hybrids millions of years ago. In the 1920s, Soviet dictator Joseph Stalin sent an animal-breeding expert to Africa in hopes of creating an army of half-man, half-monkey soldiers. Attempts both to inseminate women with monkey sperm and impregnate female chimpanzees with human sperm failed.

That doesn't mean that tales of humans interbreeding with other animals haven't endured. Rumored animal-human crosses from the past few hundred years have included a man-pig, a monkey-girl, and a porcupine man. ( slate.com )

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