Australian researchers, who spent years towing seal-shaped decoys through waters infested with great white sharks, have determined that wrapping the lures in very bright lights — sort of like aquatic Christmas trees — seems to turn sharks away.

That’s because, from below, sharks are accustomed to seeing the dark silhouettes of their prey backlighted by the sun.

So wrapping the body of a fake seal in bright, horizontally striped LED lights seems to break the silhouette into smaller pieces that no longer look like a seal, said researcher Nathan Hart, head of the School of Natural Sciences at Macquarie University in Sydney.

Hart and one of his co-authors on a study recently published in Current Biology, biologist Laura Ryan, are planning to install similarly patterned LED lights on the bottoms of surfboards to see whether that can help reduce the risk of shark attacks.

“Surfing for me is a really peaceful place. It’s about being in nature; it’s about doing something I love,” Ryan said. She’s hoping the technology might help make it just a little more peaceful.

This is not the first time scientists have looked for a technological fix for a threat that, although incredibly rare, still plays in a loop — like the ominous theme from “Jaws” — in the back of many oceangoers’ minds.

Previous researchers have tried using devices that emit electromagnetic fields to disrupt sharks’ electroreceptors. Others have tried bracelets that emit smells that sharks, theoretically, would find repulsive. Still others have marketed black-and-white striped wetsuits based on a theory similar to that behind the LED lights: disrupting the prey-like silhouette.

But for decades, the data on all such shark repellents have been “ambiguous,” said Chris Lowe, a marine biologist and director of the Shark Lab at Cal State Long Beach, who had not read the new Australian study.

The previous devices seemed to work about 40% to 50% of the time. “If your goal is to feel more confident in the water, and you can afford it, great,” Lowe said.

But he worries that some people put these things on and feel invincible, like they’re wearing “Superman’s cape.” And then they go surfing in places where sharks normally feed, putting themselves at much higher risk.

“I always put the old birth control litmus test to it,” Lowe said. “Would you be satisfied with a birth control device that only worked 40% of the time?”

One of the problems with devices designed to make people essentially invisible to sharks is that eyesight isn’t the only tool they use to detect prey: They also use their sense of smell and their ability to detect vibrations in the water.

“How important is it that a shark can’t see you if it can still smell you and feel you,” Lowe asked.

Whatever sensory input sharks use to track us down, the truth is, they’re not that interested in humans. Since 2000, millions of people have splashed around in the waters off the California coast, but there have been only 127 shark incidents recorded by the state Department of Fish and Wildlife. An “incident” is when someone is approached and touched by a shark, or the shark touches their surfboard, paddleboard or similar mode of transport.

Although it’s safe to assume everyone who experienced such an incident was well and truly freaked out, only 51 reported a physical injury. And only eight people were killed by the shark. At least seven of those deaths were caused by great whites; in the other case, the species is unknown.

You have a better chance of being killed by lightning.

To conduct their six-year study, the Australian scientists traveled to Seal Island off the coast of South Africa, the setting for countless “Shark Week” episodes and YouTube videos celebrating the sheer spectacle, and jaw-dropping violence, of great whites rocketing up from the depths and breaching the surface with doomed seals clutched in their mighty jaws.

Through the course of their research, the team learned that the arrangement and intensity of the lighting is critical. If strung vertically, along the length of the fake seal’s body, the lights don’t do enough to disrupt the silhouette visible from below. And the lights need to shine brightly enough to counteract the effect of the sun shining from above.

For optimal “counterillumination,” the scientists found, the artificial light has to be brighter than the background light.

“If you don’t get this right, it might not have the effect,” Hart said.

NASA’s Jet Propulsion Laboratory is preparing to lay off hundreds of employees this week, director Laurie Leshin said in a memo to staff sent Tuesday afternoon.

The La Cañada Flintridge research institution will let go of approximately 325 employees across the organization on Wednesday, or roughly 5% of its total staff, the memo stated.

“With lower budgets and based on the forecasted work ahead, we had to tighten our belts across the board,” Leshin wrote. “This is a message I had hoped not to have to write.”

This is the third round of layoffs at JPL this year, a reduction spurred primarily by major budgetary cuts to the Mars Sample Return mission, which is managed by JPL.

NASA directed $310 million this year to the effort to bring Mars rocks back to Earth, a steep drop from the $822.3 million it spent on the program the previous year.

In January, 100 on-site contractors at JPL were let go after NASA instructed the lab to reduce spending in anticipation of a much tighter budget. In February, the lab laid off 530 employees — approximately 8% of its workforce — and another 40 contractors.

This week’s staff reduction will bring JPL’s total workforce to about 5,500 employees, a number that managers expect will remain stable “for the foreseeable future,” Leshin told staff.

The reduction had been in the works prior to the U.S. presidential election, she wrote, and “would be happening regardless of the recent election outcome.”

The memo instructed staff to work from home on Wednesday. Employees will be notified of their job status by email.

Last year was a crisis point for Mars Sample Return, whose goal is to fetch rocks from the Red Planet’s Jezero crater and bring them back to Earth for study.

In July 2023, the U.S. Senate presented NASA with an ultimatum in its proposed budget: Either present a plan for completing the mission within the $5.3 billion budgeted, or risk cancellation.

A sobering independent review two months later determined there was “near zero probability” of Mars Sample Return making its proposed 2028 launch date, and “no credible” way to fulfill the mission within its current budget. As designed, the review board found, the mission would probably cost up to $11 billion and not return samples to Earth until at least 2040.

In response, NASA put out a request for alternative proposals to all of its centers and the private sector, essentially putting JPL in a position of having to compete for its own project.

Lawmakers lobbied to preserve JPL’s funding, citing the need to protect jobs and keep the U.S. space program competitive. China has announced a sample return mission of its own to launch in 2028 or 2030.

But funding across NASA, adjusted for inflation, has plummeted from its Apollo-era high and remained essentially flat for decades.

NASA’s budget for years has hovered around 0.1% of total U.S. gross domestic product — less than one-eighth of its allowance during the mid-1960s.

The National Academies of Sciences, Engineering, and Medicine said earlier this year that the agency is suffering under budgets that fall far short of what’s needed to support its ambitions.

In a September report commissioned by Congress, experts from the National Academies identified a number of the agency’s technological resources in decline from a lack of funds, including the Deep Space Network — an international collection of giant radio antennas overseen by JPL.

Either the U.S. must increase funding for NASA, or the agency must cut some missions, the authors concluded.

“For NASA, this is not a time for business as usual,” lead author Norman Augustine, a former executive at Lockheed Martin, said in September. “The concerns it faces are ones that have built up over decades.”

A prominent neuroscientist at USC is on leave nearly a year after allegations of research misconduct cast doubt on his published work and derailed trials for an experimental stroke treatment.

USC Keck School of Medicine Dean Carolyn Meltzer sent an email to faculty in the department of physiology and neuroscience on Oct. 22, disclosing that professor Berislav V. Zlokovic was on leave “for an indefinite period.”

In the email, Meltzer said that professor Steve Kay would serve as acting director of both the Zilkha Neurogenetic Institute and the department of physiology and neuroscience, positions that Zlokovic formerly held.

A spokesperson confirmed Zlokovic’s leave and Kay’s acting appointments on Monday but declined to provide further details, citing confidentiality surrounding personnel matters. Zlokovic didn’t immediately respond to requests for comment Monday.

Late last year, a group of whistleblowers submitted a report to the National Institutes of Health questioning the integrity of Zlokovic’s research and the safety of an experimental stroke treatment developed by ZZ Biotech, the company he co-founded.

The report identified allegedly doctored images and data in 35 research papers in which Zlokovic was the sole common author. It also questioned findings in the Phase II clinical trials of 3K3A-APC, a drug intended to reduce post-stroke brain bleeds.

The whistleblowers’ findings and news of Zlokovic’s leave were first reported in the journal Science.

On Sept. 26, Houston-based ZZ Biotech officially canceled 3K3A-APC’s clinical trial, according to a notice of withdrawal filed on the government’s database of clinical research studies.

“Any decisions on the future development pathway of 3K3A-APC in stroke will need to wait until the investigations of Dr. Zlokovic are complete,” ZZ Biotech Chief Executive Kent Pryor said Monday. Zlokovic no longer has any managerial or scientific affiliation with the company but remains a minority equity holder as co-founder, Pryor said.

NIH paused the trial in November 2023. It also launched an investigation into Zlokovic and instructed USC to return $1.9 million in funding already supplied for the study, Science reported.

A spokesperson for USC didn’t immediately respond to questions about the university’s obligations to return any federal money related to the study.

Zlokovic is a leading researcher on the blood-brain barrier, with particular interest in its role in stroke and dementia. After joining the USC faculty in 1989, he left and spent 11 years at the University of Rochester before returning to USC in 2011. He was appointed director of USC’s Zilkha Neurogenetic Institute the following year.

He retained his department chair and institute director titles as USC launched an investigation after the whistleblower report.

Since the allegations became public, three of Zlokovic’s hundreds of published research papers have been retracted. Eight more have been issued corrections or expressions of concern, a note journals append to articles when they believe there may be a problem with a paper but have not proved so.

Dr. Matthew Schrag, an assistant professor of neurology at Vanderbilt who co-authored the whistleblower report independently of his work at the university, previously told The Times that he and his colleagues did not find evidence of manipulated data in the drug trial. But given the degree of concern surrounding Zlokovic’s earlier work, he said, a clinical trial relying on his research to treat patients in life-threatening situations deserved further scrutiny.

“When you’re seeing a red flag or a trend in the clinical trial, I would tend to give that more weight in the setting of serious ethical concerns around the pre-clinical data,” Schrag said earlier this year. Schrag didn’t immediately respond to requests for comment Monday.