The Higgs boson has been spotted bottoming out — but that’s a good thing.

Physicists have detected the elementary particle decaying into two bottom quarks, exotic, short-lived particles that often appear in the aftermath of high-energy particle collisions. The elusive process was finally observed six years after the Higgs boson’s initial discovery, by physicists working at the Large Hadron Collider at CERN in Geneva. Researchers from two LHC experiments, ATLAS and CMS, reported their results simultaneously in a seminar held at CERN on August 28.
Scientists don’t detect the Higgs boson directly. Instead, they spot the debris produced when the Higgs disintegrates into less massive particles. The Higgs boson is expected to decay to two bottom quarks more than half of the time. But scientists hadn’t been able to tease out the process until now, because other mechanisms can produce bottom quarks and mimic the Higgs decay (SN: 9/3/16, p. 13). Scientists previously saw the Higgs break down into other types of particles, including particles of light called photons, a process which has fewer issues with Higgs impersonators.

With the Higgs boson’s unveiling in 2012, physicists filled in the last missing piece of the standard model, the theory of the fundamental constituents of matter (SN: 7/28/12, p. 5). But physicists still want to know more about the Higgs’ inner workings.

The standard model makes predictions of how often the Higgs should decay into different types of particles. Bottom quarks are one of six types of quarks in the standard model, each of which has different properties, such as mass and electric charge. While the lightest quarks make up commonplace particles like protons and neutrons, bottom quarks are relatively heavy and rare.

Physicists want to measure the various ways the Higgs boson decays to see if the rates match expectations. If not, that could mean something is wrong with the theory. But the new results upheld the standard model.

Gun deaths occur worldwide, but a new survey reveals the hot spots for those that occur outside of war zones.

In 2016, firearm-related homicides, suicides and accidental deaths were highly concentrated. For example, just six countries — the United States, Brazil, Mexico, Colombia, Venezuela and Guatemala — accounted for about half of the estimated number of gun deaths unrelated to armed conflict, even though the nations together contributed less than 10 percent of the world’s population.
That’s just one takeaway from the first look at the global impact of interpersonal and self-inflicted gun violence on public health, published online August 28 in JAMA. Here’s the big picture:

Total global gun deaths rose from 1990 to 2016
Worldwide, an estimated 251,000 people died from guns due to homicide, suicide or unintentional injury in 2016. That’s up from an estimated 209,000 such firearm deaths in 1990, the team found by analyzing data from 195 countries and territories from 1990 to 2016.

In 2016, 64 percent of gun-related deaths were homicides, 27 percent were suicides and 9 percent were accidental deaths.
But the rate of gun deaths dipped a bit
The researchers looked at the global rate of firearm deaths, adjusted for differences in the distribution of ages in a population. The rate decreased slightly, from 4.2 deaths per 100,000 in 1990 to 3.4 deaths per 100,000 in 2016, because the global population grew.

Even so, “we can see the number of deaths due to gun violence — homicide, suicide, unintentional injury — is very high,” says study coauthor and global health researcher Mohsen Naghavi of the University of Washington in Seattle. “Gun violence is a public health problem.”
More gun deaths occur outside of war zones than inside
Globally, for every year studied save one, gun deaths due to homicide, suicide and unintentional injury exceeded those due to conflict and terrorism. The exception: 1994, the year of the Rwandan genocide. That year, the death toll from global conflict reached 551,000, compared with 232,000 deaths from gun homicides, suicides and unintentional injuries.

The United States and Brazil are hot spots of gun violence
These two countries accounted for 32 percent of the total number of estimated deaths in 2016. In Brazil and the other top four Latin America countries, most gun deaths were homicides. The high rate of gun homicide in these countries is associated with drug and weapon trafficking, research has found. One-fourth of all global gun-related homicides in 2016 took place in Brazil.
But in the United States, as in some other wealthy countries, such as France and Germany, suicide accounted for the majority of gun deaths in 2016. Thirty-five percent of all global firearm suicides that year occurred in the United States, the researchers estimate.

Suicide rates have risen across the United States since 1999 (SN: 7/7/18, p. 13). Previous research has shown that having guns in the house is linked to higher use of the weapons to commit suicide and to a larger number of unintentional gun-related deaths.

A new experiment gives rubidium atoms a certain je ne sais quoi.

Scientists arranged individual atoms of the element rubidium into a variety of 3-D shapes, including the Eiffel Tower. The team used a laser to trap atoms in the arrangements, performing a hologram-style technique to encode the complex positions. And moveable, laser-based “tweezers” (SN: 5/12/18, p. 24) shifted atoms that were in the wrong position, researchers from the Institut d’Optique Graduate School in Palaiseau, France, report in the Sept. 6 Nature.

In addition to the Parisian landmark, the researchers sculpted a cone, a doughnut and a Möbius strip — a twisted ring with the unusual property of having only one side (SN Online: 7/24/07). The technique may be helpful for creating atomic quantum computers, which could make calculations by manipulating the interactions between individual atoms (SN: 7/8/17, p. 28).

If Earth’s magnetic field resembles that of a bar magnet, Jupiter’s field looks like someone took a bar magnet, bent it in half and splayed it at both ends.

The field emerges in a broad swath across Jupiter’s northern hemisphere and re-enters the planet both around the south pole and in a concentrated spot just south of the equator, researchers report in the Sept. 6 Nature.

“We were baffled” at the finding, says study coauthor Kimberly Moore, a graduate student at Harvard University.
The new look at Jupiter’s magnetic field comes courtesy of NASA’s Juno spacecraft, which has been orbiting the planet since July 2016 (SN: 6/25/16, p. 16). Relying on nearly 2,000 measurements of the field outside the planet, Moore and colleagues created maps detailing how the field emerges by calculating how it extends to roughly 10,000 kilometers below the cloud tops.
The results “complicate our picture of Jupiter’s interior,” Moore says. Planetary magnetism arises from electrically conductive fluids within a planet. Typical simulations for how these fluids generate magnetism can explain a field that resembles that of a bar magnet, such as Earth’s or Saturn’s, as well as those that are messy all over, like the ones at Uranus and Neptune. Jupiter’s split personality is harder to explain.

One possibility is that the extreme temperature and pressure near Jupiter’s core create a soup of rock and ice partly dissolved in liquid metallic hydrogen. Here, the interplay of turbulent layers might generate a convoluted magnetic field. Or perhaps squalls of helium rain closer to the clouds stir up conductive layers below, contorting the field before it emerges from the clouds.

The ghost catfish transforms from glassy to glam when white light passes through its mostly transparent body. Now, scientists know why.

The fish’s iridescence comes from light bending as it travels through microscopic striped structures in the animal’s muscles, researchers report March 13 in the Proceedings of the National Academy of Sciences.

Many fishes with iridescent flair have tiny crystals in their skin or scales that reflect light (SN: 4/6/21). But the ghost catfish (Kryptopterus vitreolus) and other transparent aquatic species, like eel larvae and icefishes, lack such structures to explain their luster.

The ghost catfish’s see-through body caught the eye of physicist Qibin Zhao when he was in an aquarium store. The roughly 5-centimeter-long freshwater fish is a popular ornamental species. “I was standing in front of the tank and staring at the fish,” says Zhao, of Shanghai Jiao Tong University. “And then I saw the iridescence.”

To investigate the fish’s colorful properties, Zhao and colleagues first examined the fish under different lighting conditions. The researchers determined its iridescence arose from light passing through the fish rather than reflecting off it. By using a white light laser to illuminate the animal’s muscles and skin separately, the team found that the muscles generated the multicolored sheen.
The researchers then characterized the muscles’ properties by analyzing how X-rays scatter when traveling through the tissue and by looking at it with an electron microscope. The team identified sarcomeres — regularly spaced, banded structures, each roughly 2 micrometers long, that run along the length of muscle fibers — as the source of the iridescence.

The sarcomeres’ repeating bands, comprised of proteins that overlap by varying amounts, bend white light in a way that separates and enhances its different wavelengths. The collective diffraction of light produces an array of colors. When the fish contracts and relaxes its muscles to swim, the sarcomeres slightly change in length, causing a shifting rainbow effect.
The purpose of the ghost catfish’s iridescence is a little unclear, says Heok Hee Ng, an independent ichthyologist in Singapore who was not involved in the new study. Ghost catfish live in murky water and seldom rely on sight, he says. But the iridescence might help them visually coordinate movements when traveling in schools, or it could help them blend in with shimmering water to hide from land predators, like some birds, he adds.

Regardless of function, Ng is excited to see scientists exploring the ghost catfish’s unusual characteristics.

“Fishes actually have quite a number of these interesting structures that serve them in many ways,” he says. “And a lot of these structures are very poorly studied.”

Tiny particles of plastic have been found everywhere — from the deepest place on the planet, the Mariana Trench, to the top of Mount Everest. And now more and more studies are finding that microplastics, defined as plastic pieces less than 5 millimeters across, are also in our bodies.

“What we are looking at is the biggest oil spill ever,” says Maria Westerbos, founder of the Plastic Soup Foundation, an Amsterdam-based nonprofit advocacy organization that works to reduce plastic pollution around the world. Nearly all plastics are made from fossil fuel sources. And microplastics are “everywhere,” she adds, “even in our bodies.”
In recent years, microplastics have been documented in all parts of the human lung, in maternal and fetal placental tissues, in human breast milk and in human blood. Microplastics scientist Heather Leslie, formerly of Vrije Universiteit Amsterdam, and colleagues found microplastics in blood samples from 17 of 22 healthy adult volunteers in the Netherlands. The finding, published last year in Environment International, confirms what many scientists have long suspected: These tiny bits can get absorbed into the human bloodstream.

“We went from expecting plastic particles to be absorbable and present in the human bloodstream to knowing that they are,” Leslie says.
The findings aren’t entirely surprising; plastics are all around us. Durable, versatile and cheap to manufacture, they are in our clothes, cosmetics, electronics, tires, packaging and so many more items of daily use. And the types of plastic materials on the market continues to increase. “There were around 3,000 [plastic materials] when I started researching microplastics over a decade ago,” Leslie says. “Now there are over 9,600. That’s a huge number, each with its own chemical makeup and potential toxicity.”

Though durable, plastics do degrade, by weathering from water, wind, sunlight or heat — as in ocean environments or in landfills — or by friction, in the case of car tires, which releases plastic particles along roadways during motion and braking.

In addition to studying microplastic particles, researchers are also trying to get a handle on nanoplastics, particles which are less than 1 micrometer in length. “The large plastic objects in the environment will break down into micro- and nanoplastics, constantly raising particle numbers,” says toxicologist Dick Vethaak of the Institute for Risk Assessment Sciences at Utrecht University in the Netherlands, who collaborated with Leslie on the study finding microplastics in human blood.

Nearly two decades ago, marine biologists began drawing attention to the accumulation of microplastics in the ocean and their potential to interfere with organism and ecosystem health (SN: 2/20/16, p. 20). But only in recent years have scientists started focusing on microplastics in people’s food and drinking water — as well as in indoor air.

Plastic particles are also intentionally added to cosmetics like lipstick, lip gloss and eye makeup to improve their feel and finish, and to personal care products, such as face scrubs, toothpastes and shower gels, for the cleansing and exfoliating properties. When washed off, these microplastics enter the sewage system. They can end up in the sewage sludge from wastewater treatment plants, which is used to fertilize agricultural lands, or even in treated water released into waterways.

What if any damage microplastics may do when they get into our bodies is not clear, but a growing community of researchers investigating these questions thinks there is reason for concern. Inhaled particles might irritate and damage the lungs, akin to the damage caused by other particulate matter. And although the composition of plastic particles varies, some contain chemicals that are known to interfere with the body’s hormones.

Currently there are huge knowledge gaps in our understanding of how these particles are processed by the human body.

How do microplastics get into our bodies?
Research points to two main entry routes into the human body: We swallow them and we breathe them in.

Evidence is growing that our food and water is contaminated with microplastics. A study in Italy, reported in 2020, found microplastics in everyday fruits and vegetables. Wheat and lettuce plants have been observed taking up microplastic particles in the lab; uptake from soil containing the particles is probably how they get into our produce in the first place.

Sewage sludge can contain microplastics not only from personal care products, but also from washing machines. One study looking at sludge from a wastewater treatment plant in southwest England found that if all the treated sludge produced there were used to fertilize soils, a volume of microplastic particles equivalent to what is found in more than 20,000 plastic credit cards could potentially be released into the environment each month.

On top of that, fertilizers are coated with plastic for controlled release, plastic mulch film is used as a protective layer for crops and water containing microplastics is used for irrigation, says Sophie Vonk, a researcher at the Plastic Soup Foundation.

“Agricultural fields in Europe and North America are estimated to receive far higher quantities of microplastics than global oceans,” Vonk says.
A recent pilot study commissioned by the Plastic Soup Foundation found microplastics in all blood samples collected from pigs and cows on Dutch farms, showing livestock are capable of absorbing some of the plastic particles from their feed, water or air. Of the beef and pork samples collected from farms and supermarkets as part of the same study, 75 percent showed the presence of microplastics. Multiple studies document that microplastic particles are also in fish muscle, not just the gut, and so are likely to be consumed when people eat seafood.

Microplastics are in our drinking water, whether it’s from the tap or bottled. The particles may enter the water at the source, during treatment and distribution, or, in the case of bottled water, from its packaging.

Results from studies attempting to quantify levels of human ingestion vary dramatically, but they suggest people might be consuming on the order of tens of thousands of microplastic particles per person per year. These estimates may change as more data come in, and they will likely vary depending on people’s diets and where they live. Plus, it is not yet clear how these particles are absorbed, distributed, metabolized and excreted by the human body, and if not excreted immediately, how long they might stick around.

Babies might face particularly high exposures. A small study of six infants and 10 adults found that the infants had more microplastic particles in their feces than the adults did. Research suggests microplastics can enter the fetus via the placenta, and babies could also ingest the particles via breast milk. The use of plastic feeding bottles and teething toys adds to children’s microplastics exposure.

Microplastic particles are also floating in the air. Research conducted in Paris to document microplastic levels in indoor air found concentrations ranging from three to 15 particles per cubic meter of air. Outdoor concentrations were much lower.

Airborne particles may turn out to be more of a concern than those in food. One study reported in 2018 compared the amount of microplastics present within mussels harvested off Scotland’s coasts with the amount of microplastics present in indoor air. Exposure to microplastic fibers from the air during the meal was far higher than the risk of ingesting microplastics from the mussels themselves.

Extrapolating from this research, immunologist Nienke Vrisekoop of the University Medical Center Utrecht says, “If I keep a piece of fish on the table for an hour, it has probably gathered more microplastics from the ambient air than it has from the ocean.”
What’s more, a study of human lung tissue reported last year offers solid evidence that we are breathing in plastic particles. Microplastics showed up in 11 of 13 samples, including those from the upper, middle and lower lobes, researchers in England reported.

Perhaps good news: Microplastics seem unable to penetrate the skin. “The epidermis holds off quite a lot of stuff from the outside world, including [nano]particles,” Leslie says. “Particles can go deep into your skin, but so far we haven’t observed them passing the barrier, unless the skin is damaged.”

What do we know about the potential health risks?
Studies in mice suggest microplastics are not benign. Research in these test animals shows that lab exposure to microplastics can disrupt the gut microbiome, lead to inflammation, lower sperm quality and testosterone levels, and negatively affect learning and memory.

But some of these studies used concentrations that may not be relevant to real-world scenarios. Studies on the health effects of exposure in humans are just getting under way, so it could be years before scientists understand the actual impact in people.

Immunologist Barbro Melgert of the University of Groningen in the Netherlands has studied the effects of nylon microfibers on human tissue grown to resemble lungs. Exposure to nylon fibers reduced both the number and size of airways that formed in these tissues by 67 percent and 50 percent, respectively. “We found that the cause was not the microfibers themselves but rather the chemicals released from them,” Melgert says.

“Microplastics could be considered a form of air pollution,” she says. “We know air pollution particles tend to induce stress in our lungs, and it will probably be the same for microplastics.”

Vrisekoop is studying how the human immune system responds to microplastics. Her unpublished lab experiments suggest immune cells don’t recognize microplastic particles unless they have blood proteins, viruses, bacteria or other contaminants attached. But it is likely that such bits will attach to microplastic particles out in the environment and inside the body.

“If the microplastics are not clean … the immune cells [engulf] the particle and die faster because of it,” Vrisekoop says. “More immune cells then rush in.” This marks the start of an immune response to the particle, which could potentially trigger a strong inflammatory reaction or possibly aggravate existing inflammatory diseases of the lungs or gastrointestinal tract.
Some of the chemicals added to make plastic suitable for particular uses are also known to cause problems for humans: Bisphenol A, or BPA, is used to harden plastic and is a known endocrine disruptor that has been linked to developmental effects in children and problems with reproductive systems and metabolism in adults (SN: 7/18/09, p. 5). Phthalates, used to make plastic soft and flexible, are associated with adverse effects on fetal development and reproductive problems in adults along with insulin resistance and obesity. And flame retardants that make electronics less flammable are associated with endocrine, reproductive and behavioral effects.

“Some of these chemical products that I worked on in the past [like the polybrominated diphenyl ethers used as flame retardants] have been phased out or are prohibited to use in new products now [in the European Union and the United States] because of their neurotoxic or disrupting effects,” Leslie says.
Concerning chemicals
Bits of plastic floating in the world’s air and water contain chemicals that may pose risks to human health. A 2021 study identified more than 2,400 chemicals of potential concern found in plastics or used in their processing. Here are a few of the most worrisome.

Short-chain chlorinated paraffins are used as lubricants, flame retardants and plasticizers. They can cause cancer in lab rodents, but the mechanisms may not be relevant for human health.
The chlorinated compound mirex was once used as a flame retardant and can persist in the environment. It’s suspected of being a human carcinogen and may affect fertility.
2,4,6-Tri-tert-butylphenol is an antioxidant and ultraviolet stabilizer, added to plastics to prevent degradation. There’s evidence that it causes liver damage in lab animals with prolonged or repeated exposure.
Benzo(a)pyrene is a polyaromatic hydrocarbon that can be released when organic matter such as coal or wood burns. It is also produced in grilled meats. It has been shown to cause cancer, damage fertility and affect development in lab animals.
Dibutyl phthalate is a plasticizer that is known to cause endocrine disruption, may interfere with male fertility and has been shown to affect fetal development in lab animals.
Tetrabromobisphenol-A is a flame retardant that can cause cancer in lab animals and may be an endocrine disruptor. It is chemically related to bisphenol A, which has been linked to developmental effects in children.
SOURCE: H. WIESINGER, Z. WANG AND S. HELLWEG/ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021
What are the open questions?
The first step in determining the risk of microplastics to human health is to better understand and quantify human exposure. Polyrisk — one of five large-scale research projects under CUSP, a multidisciplinary group of researchers and experts from 75 organizations across 21 European countries studying micro- and nanoplastics — is doing exactly that.

Immunotoxicologist Raymond Pieters, of the Institute for Risk Assessment Sciences at Utrecht University and coordinator of Polyrisk, and colleagues are studying people’s inhalation exposure in a number of real-life scenarios: near a traffic light, for example, where cars are likely to be braking, versus a highway, where vehicles are continuously moving. Other scenarios under study include an indoor sports stadium, as well as occupational scenarios like the textile and rubber industry.

Melgert wants to know how much microplastic is in our houses, what the particle sizes are and how much we breathe in. “There are very few studies looking at indoor levels [of microplastics],” she says. “We all have stuff in our houses — carpets, insulation made of plastic materials, curtains, clothes — that all give off fibers.”

Vethaak, who co-coordinates MOMENTUM, a consortium of 27 research and industry partners from the Netherlands and seven other countries studying microplastics’ potential effects on human health, is quick to point out that “any measurement of the degree of exposure to plastic particles is likely an underestimation.” In addition to research on the impact of microplastics, the group is also looking at nanoplastics. Studying and analyzing these smallest of plastics in the environment and in our bodies is extremely challenging. “The analytical tools and techniques required for this are still being developed,” Vethaak says.

Vethaak also wants to understand whether microplastic particles coated with bacteria and viruses found in the environment could spread these pathogens and increase infection rates in people. Studies have suggested that microplastics in the ocean can serve as safe havens for germs.

Alongside knowing people’s level of exposure to microplastics, the second big question scientists want to understand is what if any level of real-world exposure is harmful. “This work is confounded by the multitude of different plastic particle types, given their variations in size, shape and chemical composition, which can affect uptake and toxicity,” Leslie says. “In the case of microplastics, it will take several more years to determine what the threshold dose for toxicity is.”

Several countries have banned the use of microbeads in specific categories of products, including rinse-off cosmetics and toothpastes. But there are no regulations or policies anywhere in the world that address the release or concentrations of other microplastics — and there are very few consistent monitoring efforts. California has recently taken a step toward monitoring by approving the world’s first requirements for testing microplastics in drinking water sources. The testing will happen over the next several years.

Pieters is very pragmatic in his outlook: “We know ‘a’ and ‘b,’” he says. “So we can expect ‘c,’ and ‘c’ would [imply] a risk for human health.”

He is inclined to find ways to protect people now even if there is limited or uncertain scientific knowledge. “Why not take a stand for the precautionary principle?” he asks.

For people who want to follow Pieters’ lead, there are ways to reduce exposure.

“Ventilate, ventilate, ventilate,” Melgert says. She recommends not only proper ventilation, including opening your windows at home, but also regular vacuum cleaning and air purification. That can remove dust, which often contains microplastics, from surfaces and the air.

Consumers can also choose to avoid cosmetics and personal care products containing microbeads. Buying clothes made from natural fabrics like cotton, linen and hemp, instead of from synthetic materials like acrylic and polyester, helps reduce the shedding of microplastics during wear and during the washing process.

Specialized microplastics-removal devices, including laundry balls, laundry bags and filters that attach to washing machines, are designed to reduce the number of microfibers making it into waterways.

Vethaak recommends not heating plastic containers in the microwave, even if they claim to be food grade, and not leaving plastic water bottles in the sun.

Perhaps the biggest thing people can do is rely on plastics less. Reducing overall consumption will reduce plastic pollution, and so reduce microplastics sloughing into the air and water.

Leslie recommends functional substitution: “Before you purchase something, think if you really need it, and if it needs to be plastic.”

Westerbos remains hopeful that researchers and scientists from around the world can come together to find a solution. “We need all the brainpower we have to connect and work together to find a substitute to plastic that is not toxic and doesn’t last [in the environment] as long as plastic does,” she says.

LAS VEGAS – Chia seeds sprouted in trays have experimentally confirmed a mathematical model proposed by computer scientist and polymath Alan Turing decades ago. The model describes how patterns might emerge in desert vegetation, leopard spots and zebra stripes.

These and other blotchy and stripy features in nature are examples of what are called Turing patterns, so named because in 1952, Turing presented equations for how simple interactions between competing factors can lead to surprisingly complex surface patterns. In the case of arid regions, the competition for moisture among plants would drive the intricate distribution of vegetation.
But proving that Turing’s model explains patterns in the real world has been challenging (SN: 10/21/15). It wasn’t clear whether Turing’s idea is really behind natural distributions of vegetation. It could be that the idea is a mathematical just-so story that happens to produce similar shapes in a computer, says physicist Flavio Fenton of Georgia Tech in Atlanta.

In research presented at the American Physical Society meeting, Brendan D’Aquino, who studied in Fenton’s lab during the summer of 2022, described an experiment that seems to confirm that Turing’s model truly underlies patterns in vegetation.

The team grew chia seeds in even layers in trays and then adjusted the available moisture. In essence, the researchers were experimentally tweaking the factors that appear in the Turing equations. Sure enough, patterns resembling those seen in natural environments emerged. The patterns also strongly resembled computer simulations of the Turing model.
“In previous studies,” said D’Aquino, who is an undergraduate computer science student at Northeastern University, “people kind of retroactively fit models to observe Turing patterns that they found in the world. But here we were actually able to show that changing the relevant parameters in the model produces experimental results that we would expect.”

Although Turing patterns have been produced in some chemistry experiments and other artificial systems, the team believes this is the first time that experiments with living vegetation have verified Turing’s mathematical insight.