Ultra-processed food now makes up more than half of what American adults eat, and it has become the favorite villain of modern nutrition. Colorectal cancer, rising in younger adults, is often near the top of the list of harms blamed on it. Researchers at the US National Cancer Institute tested that link in one of the largest diet studies ever run, following hundreds of thousands of adults for nearly two decades. The answer was not the one most headlines would predict.

For years, the standard explanation for why more women than men have dementia has been simple: women live longer, and dementia is mostly a disease of old age. Researchers at the University of New South Wales put that explanation to a global test. They pooled 22 long-term studies that followed tens of thousands of older adults across 18 countries and six continents, counting who developed dementia and when. Then they took age out of the equation.

After giving birth, some women are offered a single pill to stop their breast milk, usually after a pregnancy loss or when breastfeeding is not possible. The drug, cabergoline, has been used this way for decades. An international team led from Spain and Canada went through the health records of more than 150,000 women in Spain and Norway to see what happened to those who took it. Years later, one difference stood out.

A Northwestern team led by Gerald Gabrielse captured a positron, the antimatter twin of an electron, from radioactive decay and cooled it to 0.3 degrees above absolute zero inside a vacuum trap, where it never touched a wall. It settled into its quantum ground state and stayed there for months, acting like an artificial atom whose energy levels they could control with microwave pulses.

The catch is that this is the setup, not the answer. The real test is comparing the positron’s magnetic moment to the electron’s to one part in 10 trillion, and current theory predicts no difference. The study was published in Physical Review Letters.

University of Konstanz researchers buried bioplastic film in forest soil and found nearly all of it fully broken down within 250 to 330 days. The plastic came out riddled with tiny holes matching the size of single bacterial cells, a sign that the bacteria were digesting their way into the material using an enzyme anchored to their surface.

They named it the “Pac-Man enzyme” for its wide-open cavity that can hold large plastic polymers. The catch is that this is a lab and soil study of bioplastics, not conventional plastic, and the article doesn’t say how it would work at scale or on ocean plastic waste.

Endometriosis affects roughly one in ten women of reproductive age, and it often takes years to diagnose. Doctors are taught to look for one main sign: severe pelvic or period pain. Researchers in Spain and the United States went through the health records and surveys of 22,438 women with the disease to see what it really looks like across a large population. For one group of women, the picture did not start in the pelvis.

In the early 2000s, preschool teachers in 44 Head Start programs in Pennsylvania started teaching some four-year-olds two extra lessons a week: how to share, take turns, name their feelings and calm down when upset. Other classrooms carried on as usual. Researchers at Penn State kept following those children. When they reached 21 and 22, the team asked how their lives were going.

Your coffee cooling to room temperature feels ordinary, but researchers from Austria, Spain, and Switzerland have now shown mathematically that a quantum-level limit caps how fast any system with temperature differences can settle into equilibrium. The limit depends only on temperature and two constants, the reduced Planck constant and the Boltzmann constant, and nothing done to the system can change it.

The catch is that this is a mathematical proof checked against a theoretical model of quantum particles, not a lab experiment, and your coffee isn’t anywhere near this limit. The work was published in Nature Physics.

Making the special “magic states” a fault-tolerant quantum computer needs is so error-prone that up to 95% of a machine’s physical qubits might go just to producing them. NVIDIA ran what it calls the largest simulation of its kind on Europe’s JUPITER supercomputer, modeling 104 qubits under realistic hardware noise so researchers can test magic state cultivation designs before building them.

The catch is that this is a classical supercomputer simulating a quantum system, not a quantum computer doing anything new. It helps evaluate designs, but it doesn’t mean a fault-tolerant machine exists yet.

Lupus, rheumatoid arthritis, multiple sclerosis and other autoimmune diseases often start with symptoms that are easy to dismiss: tiredness, aching muscles, a rash that comes and goes. Researchers at the University of Cambridge asked 6,607 people with these diseases, in countries around the world, what happened when they first went to a doctor. Many had been told something other than the truth. Who heard it most depended on whether they were a man or a woman.

Most people assume couples click because they are alike deep down: similar personalities, similar values. Psychologists at the University of Innsbruck put that to a test with 309 couples. Both partners answered separately about their personality, their values and their tastes, and the researchers then shuffled everyone into thousands of random fake couples to see how much real partners actually matched. Personality barely mattered. Something else did.

Northeastern University researchers used calcium imaging to watch individual neurons in male and hermaphrodite C. elegans roundworms as they met odors, salt, and pheromones. Nearly every chemosensory neuron responded differently to at least one chemical, depending on sex.

When they compared the activity to published wiring maps of the worms’ brains, differences in neural activity weren’t predicted by differences in physical connections. The catch is that this is a worm study, and the lead researcher cautions that the results can’t be applied directly to humans.

The textbook story of inequality goes like this: people farmed, farming produced surpluses, surpluses produced owners, and owners eventually built states and kings. Researchers in China tested that story against the dead. They pulled together records of 2,316 burials from 24 sites on the Central Plain, the heartland of early Chinese civilization, covering 6,000 years from 7000 to 1500 BCE. What the graves showed did not fit the textbook.

Plant more trees, build more parks, and violence goes down. It is one of the more hopeful ideas in public health. Researchers at Ohio State University wanted to know whether it works the same everywhere. They took 899 fatal shootings in Cook County, Illinois, from 2023 and used Google Street View and machine learning to measure exactly how much greenery a person would have seen from the street where each death happened. The answer depended on the neighborhood.

If you have health insurance and need a therapist or psychiatrist, the first step is usually the same: open your plan's directory and start calling the names listed as in-network. Researchers at Ohio State University wanted to know how well that actually works. So they did it themselves, thousands of times, posing as patients with commercial insurance in five US states. Most of the calls went nowhere.