“We’re lucky to live and work in Panama where nature has set up its own evolutionary experiment,” said Aaron O’Dea, STRI paleontologist. “When the Caribbean Sea was isolated from the Pacific Ocean by the slow uplift of the Isthmus of Panama, nutrient levels fell and Caribbean coral reefs proliferated. We can use the excellent fossil record to observe how Caribbean life responded to this dramatic environmental and ecological transformation.”

The team’s best choice for tracking the change was a peculiar family of marine animals known as the cupuladriid bryozoans. These relatively small animals consist of unusual, free-living, disc-shaped colonies of individuals called zooids. “Colonies form through sexual reproduction or asexually by cloning, as bits of the colony break off and continue to grow,” said STRI post-doc and coauthor Blanca Figuerola. “They abound on the sea floor along the continental shelf across the tropics, filtering plankton from the water via a beautiful waving crown of tentacles. When colonies die, their hard skeletons remain, and are exceptionally abundant as fossils.”

O’Dea’s group collected and identified more than 90,000 cupuladriid colonies from 200 fossil samples and 90 more recent samples collected by dredging the sea floor. The samples contained mud, sand, coral remains and other indicators of the kind of habitats where the bryozoans had lived. The team measured the abundances of the 10 most common species along gradients of these environmental and ecological indicators.

“We were intrigued to find that, even though all species could expand into the new Caribbean habitats created after final formation of the Isthmus, different species did so at different speeds,” said O’Dea. “The patterns were clear — old species that originated before 8 million years ago took 2 million years longer to expand into the new habitats than the younger species.”

“Perhaps younger species, which have smaller populations, are less tied to their history,” said former STRI post-doc and University of Saskatchewan researcher

Santosh Jagadeeshan, another co-author. “Old species, with large, settled populations may be less able to escape from established roles and defined environmental tolerances because they mate with each other creating a high gene flow that makes it hard for genes for new traits to become established. It seems you can’t teach an old dog new tricks in evolution, either.”

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The Rice lab of chemical engineer Sibani Lisa Biswal made a magnetic nanoparticle compound that efficiently separates crude oil droplets from produced water that have proven difficult to remove with current methods.

The research is detailed in a paper in the Royal Society of Chemistry journal Environmental Science: Water Research & Technology.

Produced water comes from production wells along with oil. It often includes chemicals and surfactants pumped into a reservoir to push oil to the surface from tiny pores or cracks, either natural or fractured, deep underground. Under pressure and the presence of soapy surfactants, some of the oil and water form stable emulsions that cling together all the way back to the surface.

While methods exist to separate most of the oil from the production flow, engineers at Shell Global Solutions, which sponsored the project, told Biswal and her team that the last 5 percent of oil tends to remain stubbornly emulsified with little chance to be recovered.

“Injected chemicals and natural surfactants in crude oil can oftentimes chemically stabilize the oil-water interface, leading to small droplets of oil in water which are challenging to break up,” said Biswal, an associate professor of chemical and biomolecular engineering and of materials science and nanoengineering.

The Rice lab’s experience with magnetic particles and expertise in amines, courtesy of former postdoctoral researcher and lead author Qing Wang, led it to combine techniques. The researchers added amines to magnetic iron nanoparticles. Amines carry a positive charge that helps the nanoparticles find negatively charged oil droplets. Once they do, the nanoparticles bind the oil. Magnets are then able to pull the droplets and nanoparticles out of the solution.

“It’s often hard to design nanoparticles that don’t simply aggregate in the high salinities that are typically found in reservoir fluids, but these are quite stable in the produced water,” Biswal said.

The enhanced nanoparticles were tested on emulsions made in the lab with model oil as well as crude oil.

In both cases, researchers inserted nanoparticles into the emulsions, which they simply shook by hand and machine to break the oil-water bonds and create oil-nanoparticle bonds within minutes. Some of the oil floated to the top, while placing the test tube on a magnet pulled the infused nanotubes to the bottom, leaving clear water in between.

Best of all, Biswal said, the nanoparticles can be washed with a solvent and reused while the oil can be recovered. The researchers detailed six successful charge-discharge cycles of their compound and suspect it will remain effective for many more.

She said her lab is designing a flow-through reactor to process produced water in bulk and automatically recycle the nanoparticles. That would be valuable for industry and for sites like offshore oil rigs, where treated water could be returned to the ocean.

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Writing in Science Robotics, scientists say social robots are proving effective in the teaching of certain narrow subjects, such as vocabulary or prime numbers.

But current technical limitations — particularly around speech recognition and the ability for social interaction — mean their role will largely be confined to that of teaching assistants or tutors, at least for the foreseeable future.

The study was led by Professor in Robotics Tony Belpaeme, from the University of Plymouth and Ghent University, who has worked in the field of social robotics for around two decades.

He said: “In recent years scientists have started to build robots for the classroom — not the robot kits used to learn about technology and mathematics, but social robots that can actually teach. This is because pressures on teaching budgets, and calls for more personalised teaching, have led to a search for technological solutions.

“In the broadest sense, social robots have the potential to become part of the educational infrastructure just like paper, white boards, and computer tablets. But a social robot has the potential to support and challenge students in ways unavailable in current resource-limited educational environments. Robots can free up precious time for teachers, allowing the teacher to focus on what people still do best — provide a comprehensive, empathic, and rewarding educational experience.”

The current study, compiled in conjunction with academics at Yale University and the University of Tsukuba, involved a review of more than 100 published articles, which have shown robots to be effective at increasing outcomes, largely because of their physical presence.

However it also explored in detail some of the technical constraints highlighting that speech recognition, for example, is still insufficiently robust to allow the robot to understand spoken utterances from young children.

It also says that introducing social robots into the school curriculum would pose significant logistical challenges and might in fact carry risks, with some children being seen to rely too heavily on the help offered by robots rather than simply using them when they are in difficulty.

In their conclusion, the authors add: “Next to the practical considerations of introducing robots in education, there are also ethical issues. How far do we want the education of our children to be delegated to machines? Overall, learners are positive about their experiences, but parents and teaching staff adopt a more cautious attitude.

“Notwithstanding that, robots show great promise when teaching restricted topics with the effects almost matching those of human tutoring. So although the use of robots in educational settings is limited by technical and logistical challenges for now, it is highly likely that classrooms of the future will feature robots that assist a human teacher.”

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Three years ago, research teams from the University of Chicago and the University of Utah, working separately, began to unravel why. They knew that humans, like all other animals, have one copy of the master tumor suppressor gene p53. This gene enables humans and elephants to recognize unrepaired DNA damage, a precursor of cancer. Then it causes those damaged cells to die.

Unexpectedly, however, the researchers found that elephants have 20 copies of p53. This makes their cells significantly more sensitive to damaged DNA and quicker to engage in cellular suicide.

In the August 14, 2018 issue of the journal Cell Reports, the University of Chicago team describes a second element of this process: an anti-cancer gene that returned from the dead.

“Genes duplicate all the time,” said Vincent Lynch, PhD, assistant professor of human genetics at the University of Chicago and the study’s senior author. “Sometimes they make mistakes, producing non-functional versions known as pseudogenes. We often refer to these dismissively as dead genes.”

While studying p53 in elephants, however, Lynch and colleagues found a former pseudogene called leukemia inhibitory factor 6 (LIF6) that had somehow evolved a new on-switch. LIF6, back from the dead, had become a valuable working gene. Its function, when activated by p53, is to respond to damaged DNA by killing the cell. The LIF6 gene makes a protein that goes, quite rapidly, to the mitochondria, the cell’s main energy source. That protein pokes holes in the mitochondria, causing the cell to die.

“Hence, zombie,” said Lynch. “This dead gene came back to life. When it gets turned on by damaged DNA, it kills that cell, quickly. This is beneficial, because it acts in response to genetic mistakes, errors made when the DNA is being repaired. Getting rid of that cell can prevent a subsequent cancer.”

Elephants have eight LIF genes, but only LIF6 is known to be functional. Although it was only recently described, it appears to have been helping elephants and their relatives for a long time.

“We can use the tricks of evolution to try to figure out when this defunct gene became functional again,” Lynch said. It seems to have emerged around the time when the fossil record indicates that the small groundhog-sized precursors of today’s elephants began to grow bigger. This started about 25 to 30 million years ago. This supplementary method of suppressing cancer may have been a key element enabling enormous growth, which eventually led to modern elephants.

There are significant and lasting benefits to being huge. Small animals, for example — mice, squirrels, groundhogs — get eaten all the time, mostly by larger animals. But “if you are enormous, such as an elephant or a whale, nothing is going to mess with you,” Lynch said.

There are tradeoffs, however. Bigger animals have vastly more cells, and they tend to live longer, which means more time and opportunities to accumulate cancer-causing mutations. When those cells divide, their DNA makes copies of itself. But those copies don’t match the original. Errors get introduced and the repair process can’t catch up.

“Large, long-lived animals must have evolved robust mechanisms to either suppress or eliminate cancerous cells in order to live as long as they do, and reach their adult sizes,” said study co-author Juan Manuel Vazquez, a doctoral candidate in the Lynch laboratory.

These huge animals thus have higher odds of developing cancerous cells. This can also happen on a smaller scale. Taller humans, for example, have a slightly higher incidence of several cancer types than average sized people, and shorter people tend to be at a reduced risk for those cancers.

LIF6, the study authors suggest, was “reanimated sometime before the demands of maintaining a larger body existed.” It helped enable the growth of animals that were the size of a 10-pound groundhog into majestic creatures that can weigh more than 15,000 pounds. It was “permissive for the origin of large bodies,” the authors note, “but not sufficient.”

Exactly how LIF6 induces apoptosis, however, remains unclear. This will be “the focus of continued studies,” the authors wrote.