Exploratory behaviors in the Iowa Gambling Task seem to decline with aging

When it comes to the diagnosis of pigmented skin lesions, artificial intelligence is superior to humans. In a study conducted under the supervision of the MedUni Vienna human experts "competed" against computer algorithms. The algorithms achieved clearly better results, yet their current abilities cannot replace humans. 

The International Skin Imaging Collaboration (ISIC) and the MedUni Vienna organized an international challenge to compare the diagnostic skills of 511 physicians with 139 computer algorithms (from 77 different machine learnings labs). A database of more than 10.000 images, which was established by the team around Harald Kittler at the Department of Dermatology of MedUni Vienna in cooperation with the University of Queensland (Australia), was used as a training set for the machines. This database includes benign (moles, sun spots, senile warts, angiomas, and dermatofibromas) and malignant pigmented lesions (melanomas, basal cell carcinoma, and pigmented squamous cell carcinoma). {module In-article} 

Each participant had to diagnose 30 randomly selected images out of a test-set of 1511 images. The result was unequivocal. While the best humans diagnosed 18.8 out of 30 cases correctly, the best machines achieved 25.4 correct diagnoses. This did not surprise first-author Philipp Tschandl from the MedUni Vienna: "Two-thirds of all participating machines were better than humans; this result had been evident in similar trials during the past years."

Not a substitute for human beings

Although the algorithms were clearly superior in this experiment, this does not mean that the machines will replace humans in the diagnosis of skin cancer. Philipp Tschandl: "The computer only analyzes an optical snapshot and is really good at it. In real life, however, the diagnosis is a complex task. Physicians usually examine the entire patient and not just single lesions. When humans make a diagnosis they also take additional information into account, such as the duration of the disease, whether the patient is at high or low risk, and the age of the patient, which was not provided in this study.

Despite the impressive performance of artificial intelligence, there is still room for improvement. The machines were significantly less accurate in the diagnosis of lesions that came from centers that did not provide training images. With regard to human performance, the experience was important. The most experienced participants with at least ten years of experience in the diagnosis of pigmented skin lesions performed best. The results were published in the journal “The Lancet Oncology."

Researchers at CU Boulder have discovered hints that humanity's favorite star may have a dual personality, with intriguing discrepancies in its magnetic fields that could hold clues to the sun's own "internal clock."

Physicists Loren Matilsky and Juri Toomre developed a supercomputer simulation of the sun's interior as a means of capturing the inner roiling turmoil of the star. In the process, the team spotted something unexpected: On rare occasions, the sun's internal dynamics may jolt out of their normal routines and switch to an alternate state--bit like a superhero trading the cape and cowl for civilian clothes.

While the findings are only preliminary, Matilsky said, they may line up with real observations of the sun dating back to the 19th century.

He added that the existence of such a solar alter-ego could provide physicists with new clues to the processes that govern the sun's internal clock--a cycle in which the sun switches from periods of high activity to low activity about once every 11 years. {module In-article}

"We don't know what is setting the cycle period for the sun or why some cycles are more violent than others," said Matilsky, a graduate student at JILA. "Our ultimate goal is to map what we're seeing in the model to the sun's surface so that we can then make predictions."

He will present the team's findings at a press briefing today at the 234th meeting of the American Astronomical Society in St. Louis.

The study takes a deep look at a phenomenon that scientists call the solar "dynamo," essentially a concentration of the star's magnetic energy. This dynamo is formed by the spinning and twisting of the hot gases inside the sun and can have big impacts--an especially active solar dynamo can generate large numbers of sunspots and solar flares, or globs of energy that blast out from the surface.

But that dynamo isn't easy to study, Matilsky said. That's because it mainly forms and evolves within the sun's interior, far out of range of most scientific instruments.

"We can't dive into the interior, which makes the sun's internal magnetism a few steps removed from real observations," he said.

To get around that limitation, many solar physicists use massive supercomputers to try to recreate what's occurring inside the sun.

Matilsky and Toomre's simulation examines activity in the outer third of that interior, which Matilsky likens to "a spherical pot of boiling water."

And, he said, this model delivered some interesting results. When the researchers ran their simulation, they first found that the solar dynamo formed to the north and south of the sun's equator. Following a regular cycle, that dynamo moved toward the equator and stopped, then reset in close agreement with actual observations of the sun.

But that regular churn wasn't the whole picture. Roughly twice every 100 years, the simulated sun did something different.

In those strange cases, the solar dynamo didn't follow that same cycle but, instead, clustered in one hemisphere over the other.

"That additional dynamo cycle would kind of wander," Matilsky said. "It would stay in one hemisphere over a few cycles, then move into the other one. Eventually, the solar dynamo would return to its original state."

That pattern could be a fluke of the model, Matilsky said, but it might also point to real, and previously unknown, the behavior of the solar dynamo. He added that astronomers have, on rare occasions, seen sunspots congregating in one hemisphere of the sun more than the other, an observation that matches the CU Boulder team's findings.

Matilsky said that the group will need to develop its model further to see if the dual dynamo pans out. But he said that the team's results could, one day, help to explain the cause of the peaks and dips in the sun's activity--patterns that have huge implications for climate and technological societies on Earth.

"It gives us clues to how the sun might shut off its dynamo and turn itself back on again," he said.