An obstructed atomic phase

In a crystal, at the atomic scale, atoms sit in a repeating lattice, like the repeating tiles of a floor. In most introductory models, electrons associated with a given band are imagined as being centered on the atoms themselves. Their “home base,” so to speak, coincides with the positions of the nuclei. But quantum mechanics allows something subtler. The electronic charge can instead be centered in the empty spaces between atoms, while still respecting the symmetry of the crystal and remaining tightly localized. This is the essence of what physicists call an obstructed atomic phase. It is “atomic” because the electrons remain localized, but “obstructed” because their centers cannot be smoothly moved back onto the atoms without changing the quantum structure of the band.

A new methodology

For years, this idea was theoretically elegant but experimentally frustrating. The challenge was not proving that such bands could exist, but actually measuring where the electronic weight lives in a real material. The breakthrough here ¹ came from combining scanning tunnelling microscopy with first-principles electronic structure calculations. Scanning tunnelling microscopy can measure how electronic states are distributed across a surface with atomic resolution, effectively turning the crystal into a quantum landscape map. By carefully analyzing these real-space spectroscopic images, the researchers reconstructed how different atomic orbitals in the material are correlated with one another. This allowed them to infer the true spatial center of the electronic band that crosses the Fermi level, the energy frontier most relevant for electrical behavior.

In the spaces

What they found is conceptually beautiful. In monolayer niobium diselenide, the relevant electronic band behaves as if its charge center sits not on a niobium or selenium atom, but on an empty symmetry point inside the unit cell. In other words, the most natural description of the electrons places them in the spaces defined by the crystal, rather than on the atoms that build it. This may sound almost philosophical, but it has real physical meaning. The geometry of where electrons are centered shapes how they respond to defects, edges, strain, and even how they may participate in more exotic collective states.

It is as if the electrons have quietly claimed the open spaces of the crystal as their true home.

The broader significance goes beyond one compound. Niobium diselenide belongs to the family of transition metal dichalcogenides, layered materials that have become central to modern quantum materials research because they can host superconductivity, charge ordering, and unusual topological effects. By showing that one of their electronic bands has this obstructed structure, the work opens a new route for understanding how real-space geometry influences electronic phases in two dimensions. The same method should also apply to many other layered compounds where topology is encoded not in edge currents or magnetic responses, but in the quiet geometry of localized electrons.

A band can be localized, compact, and seemingly simple, yet still hide a subtle internal geometry that changes how we classify the material. What makes this advance so exciting is not only that it verifies a beautiful theoretical concept, but that it gives experimentalists a practical way to visualize this hidden electronic geometry directly in real space.

Author: César Tomé López is a science writer and the editor of Mapping Ignorance

Disclaimer: Parts of this article may have been copied verbatim or almost verbatim from the referenced research paper/s.

The post Visualizing obstructed atomic phases in 2D materials appeared first on Mapping Ignorance.

 

In recent years, residents of Spain, France and the UK have looked up to see an eerie sight: deep orange sunrises and skies thick with a yellowish haze. These hazy skies often deposit “blood rain”, rust-colored precipitation that leaves a fine grit on cars and windows.

These events are caused by dust plumes from the Sahara desert that travel thousands of kilometres across the Mediterranean. As climate change alters the world’s largest desert, Europe is finding itself increasingly downwind of a shifting environmental crisis.

The Sahara accounts for more than half of the world’s total dust emissions. Under hot, dry and windy conditions, particles are lifted several kilometres into the atmosphere and transported across continents.

While most travels west toward the Americas, some moves north towards Europe, particularly between February and June. Recent plumes – such as the intense “Calima” that sometimes blankets Spain – have reached as far as the North Sea and Scandinavia.

The relationship between a warming planet and dust is complex.

On one hand, rising temperatures dry out soils and accelerate desertification, making it far easier for wind to dislodge fine particles. Under extreme warming scenarios, the amount of Saharan dust lifted into the atmosphere could rise by 40% to 60% by the end of the century.

However, the “dustiness” of the future also depends on wind patterns. Certain Saharan sand and dust storms have actually become rarer and less intense over the past two decades. Partly, this is due to an increase in vegetation in the Sahel region at the southern border of the Sahara. But it’s also down to a weakening of surface winds in general, and changes in certain large-scale climate patterns.

Health risks and economic consequences

For Europe, the impact is not just aesthetic. Saharan dust can substantially degrade air quality, pushing levels of invisible particulate matter beyond health guidelines. These fine particles, known as PM10, can penetrate deep into the lungs, triggering asthma and cardiovascular issues. In Spain and Italy, modelling studies suggest Saharan dust may account for up to 44% of deaths linked to PM10 pollution.

Dust also carries other costs. When it settles on snow in the Alps it darkens the surface and makes it less able to reflect sunlight, accelerating melting. It can reduce the efficiency of solar panels and disrupt aviation and road traffic by lowering visibility.

What to do about dust from Sahara

Responding to this growing cross-border problem means acting both at the source and in affected areas.

In the Sahara and its margins, preventing the disruption of intact soils is critical. Overgrazing, river damming and land abandonment can all increase dust emissions. To stabilise the ground, measures include restoring vegetation, maintaining river flows and protecting the fragile “biocrust” of bacteria, moss and other organisms that bind the top few millimetres of desert soils and form a natural shield against wind erosion.

In Europe, the focus is on being prepared. Early warning systems now provide predictions up to 15 days in advance, allowing health authorities to issue alerts for vulnerable people to stay indoors. Simple measures, from improved building ventilation to creating more urban green spaces, can also reduce exposure.

In decades to come, the Saharan “dust belt” will remain a visible indicator of our planet’s health. But technology and forecasting alone will not be enough to solve the problem.

Dust does not respect borders, so managing it will require stronger international cooperation – and binding agreements – on everything from managing river basins to stop lake beds from drying out, to public health responses across Europe. Whether orange skies remain a curiosity or become a regular feature of European life, governments throughout Europe and Africa must take this shared risk seriously.

 

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The post Climate change is altering Saharan dust – and Europe is downwind appeared first on Mapping Ignorance.

By comparing ancient burial practices with genetic information gleaned from the remains, researchers show that it’s not uncommon for people who aren’t related by blood to be treated as members of the same family—which means that ancient DNA doesn’t tell the whole story of how families and societies worked.

“Even in prehistory, kinship was more than just blood relations,” says Sabina Cveček, an archaeologist and Marie Skłodowska-Curie Global Fellow at the Field Museum in Chicago.

“Many communities around the world have a concept of family that goes beyond this biological setting. So no matter how hard we push with ancient DNA research, we’ll never know the whole story if we don’t take diversity and cultural anthropological perspectives into account.”

Cveček is one of the lead authors of a special issue of the Cambridge Archaeological Journal ¹ dedicated to how archaeologists, anthropologists, and geneticists determine the relationships between ancient people, and how genetic research plays a role in our understanding of these societies.

This special issue, which Cveček edited with Maanasa Raghavan (University of Chicago) and Penny Bickle (University of York), includes research about the relationship between family and genetic relatedness around the world, over the course of thousands of years.

Rethinking kinship beyond genetics

Cveček, Raghavan, and Bickle emphasized in their introductory piece that kinship cannot be reduced to genetic relatedness, and that recent archaeogenetic work—while powerful—has tended to privilege biological descent and linear pedigrees.

“The piece intervenes by showing that this is only one ‘code’ of relatedness. Instead, ancient kinship research is in need of new approaches by closely considering ethics of sampling human remains, interdisciplinary training, collaborative research design, and new interpretations that consider multiple ways of becoming kin,” says Cveček.

The team reviewed decades’ worth of previous archaeological and genetic studies from sites in Europe and western Asia. For instance, at a site called Çatalhöyük in what’s now Türkiye (sometimes called Turkey), burials were often found below the house floors of ancient houses from 8,000 years ago.

“Archaeologists initially assumed that people buried within the same house would be genetically related,” says Cveček. “But now, it is possible to map those people through ancient DNA analysis on genetic pedigrees, and geneticists often found people buried within the same house who are not at all genetically related, indicating social proximity rather than exclusively blood relations made kin at the site.”

DNA degrades over time, but traces of DNA can remain inside human bones, including small bones such as petrous bone in the inner ear. In the past few decades, scientists have been able to extract DNA from these ancient bones and sequence it.

The resulting genetic sequences are generally patchy, so “geneticists need to do a lot of computational analysis and statistics with genetic signatures from those broken pieces of ancient DNA to actually reconstruct biological relatedness of the past,” says Cveček.

What ancient families can teach today

These findings suggest that in these ancient communities, the concept of family wasn’t only dictated by blood. Since the same is true of many families today, that may not seem like an Earth-shattering discovery. But it could be a critical piece of information for researchers attempting to reconstruct how ancient cultures built and passed down their family ties. DNA doesn’t always tell the whole story.

“One of the aims of this paper is to debunk the Western perceptions of family kinship, which often seems to be based on blood. We cannot have just one proxy for understanding family or kinship around the world,” says Cveček.

This broader concept of family goes beyond archaeological and anthropological research—we run into it every day when we handle health insurance, housing, childcare, and education.

“The old saying, that it takes a village to raise a child, is true,” says Cveček. “We all invest time and labor to build a world that looks after people beyond our biological dependents.” Caring for people who aren’t blood-related to us is part of what makes us human.

The post Ancient graves and DNA uncover family bonds that went beyond genetics appeared first on Mapping Ignorance.

Levels of complexity

To grasp this idea, we must first understand that life itself is characterized by the need to “draw consequences.” This is not a metaphorical claim but a biological fact. Living beings, unlike inanimate objects, face the fundamental challenge of performing actions that are appropriate to their circumstances. A plant turns toward light because light means energy. A bacterium moves away from toxin because toxin means death. In these simplest cases, the drawing of consequences is built into the organism’s structure through natural selection. The plant does not “decide” to seek light; it simply does so, and this ability has been honed over millions of years because it worked for successful reproduction.

This basic imperative unfolds on increasingly complex levels. With the development of nervous systems in the animal kingdom, we encounter a second level of complexity: the creation of internal representations. An animal can build a mental model of its environment, remember past experiences, learn from consequences, and adapt its behavior accordingly. A squirrel that remembers where it buried nuts is drawing consequences from past experience. A chimpanzee that uses a stick to fish for termites is drawing consequences about the relationship between tools and outcomes. These are forms of intelligence that go far beyond mere reflex.

The human leap to a third level of complexity is perhaps the most significant in the history of life on Earth. We developed the capacity to create external representations of our internal representations—symbols, signs, and language that allow us to make our thoughts public, to share them with others, to examine them collectively, and to preserve them across time. An animal cannot tell another animal what she is thinking or what happened yesterday. A human can do both, and this difference has transformed everything.

Language as the fundamental inferential prosthesis

Language, from this perspective, is best understood as the fundamental inferential prosthesis. It is a system superimposed upon our biological cognitive capabilities that has astronomically multiplied our ability to draw consequences from information. Consider what language enables. First, it allows for logical reasoning. Because language has structure—grammar, syntax, rules of inference—we can move from premises to conclusions in ways that are publicly examinable and correctable. We can say “if A then B, and A is true, therefore B” and know that this inference holds for anyone who understands the terms.

Second, language enables the accumulation and transmission of knowledge across generations. The information acquired by one individual through years of experience can be passed to another who has never had that experience. A child born today can learn about the dangers of poisonous plants without ever being poisoned, about the movements of stars without ever staying up all night to watch them, about the structure of atoms without ever seeing one. This cumulative cultural evolution is possible only because language allows information to exist outside individual minds.

Third, language enables collective deliberation. We can reason together, debate competing claims, pool our cognitive resources, and arrive at conclusions that no individual could reach alone. A scientific community, a jury, a legislature—these are all institutions made possible by language, institutions that multiply our inferential capacities beyond anything a solitary mind could achieve.

This understanding of language as a prosthesis directly challenges romantic views of language, including Heidegger’s influential conception. For Heidegger, language is the “house of Being”—the sacred space where reality reveals itself authentically, particularly in poetry and mystical discourse. The language of science, technology, and everyday communication is, for him, a degenerate form that conceals rather than reveals. From the perspective of inferential prostheses, however, this distinction collapses. Poetic language is not more authentic than scientific language; it is simply a different technological tool, suited for different purposes. A poem reveals certain aspects of experience that a chemistry textbook cannot, but a chemistry textbook reveals aspects of reality that a poem cannot. Neither has “ontological primacy”; both are sophisticated, artificial creations built upon the fundamental prosthesis of language.

Technology as an inferential prosthesis

But language is not our only inferential prosthesis. The concept can be extended to all technology. A prosthesis, in the medical sense, is an artificial device that replaces or enhances a missing or damaged body part. An inferential prosthesis, by extension, is any tool or technique that enhances our ability to draw consequences and act effectively. The simplest example is a stick used by a chimpanzee to fish for ants. The stick extends the reach of the chimp’s actions—it can reach ants that would otherwise be inaccessible. But it also provides information: the chimp learns about the relationship between stick length and success, about the behavior of ants, about the properties of different kinds of sticks.

All technology can be understood through this lens. A hammer multiplies the force of your arm and allows you to drive nails that your fist could not. But it also shapes your understanding of materials—you learn what can be hammered and what cannot, what requires a heavier hammer and what requires a lighter one. A computer multiplies your ability to perform calculations, store information, and communicate with others. But it also transforms how you think about problems, what you consider possible, and how you approach intellectual challenges.

This dual aspect of technology—amplifying both our capacity to act and our capacity to know—suggests a useful distinction. We might call “material techniques” those technologies where the primary function is to amplify our ability to do things: hammers, plows, factories, transportation systems. We might call “informational techniques” those whose primary function is to amplify our ability to know things: writing, mathematics, computers, scientific instruments. This is a distinction of emphasis, not a rigid dichotomy. Every material technology provides cognitive shortcuts for its use—a well-designed hammer suggests how to be held, a well-designed interface guides its user. Every informational technology ultimately has material effects—a mathematical equation can lead to a bridge, a scientific discovery can lead to a new medicine.

No going back

The crucial insight of the inferential prosthesis perspective is that there is no going back to a pre-technological state of nature. Language itself, our most fundamental prosthesis, has made us what we are. The choice is not between technology and authenticity, as Heidegger seemed to suggest, but between different ways of designing, using, and relating to our technological extensions. The task is to become conscious of the ways our prostheses shape us, to ask what consequences they enable and what consequences they foreclose, and to wield them with the wisdom that such profound responsibility demands. We are, and always have been, prosthetic creatures. The question is not whether to use prostheses but how to use them well.

References

Zamora Bonilla, Jesús, 2017, Sacando consecuencias, Tecnos.

The post A mini-philosophy of technology (2): Technology as an inferential prosthesis appeared first on Mapping Ignorance.

Neutrinoless

The mystery begins with the neutrino, one of the strangest particles in physics. Neutrinos are everywhere, streaming through your body by the trillions every second, yet they barely interact with anything. One of the biggest open questions in the field is whether the neutrino is its own antiparticle. If it is, a very rare kind of radioactive decay, called neutrinoless double beta decay, should exist. In ordinary double beta decay, two neutrons inside a nucleus transform simultaneously and release two electrons together with two neutrinos. In the neutrinoless version, the neutrinos would somehow cancel each other out internally, leaving only the two electrons. Detecting this would show that a fundamental conservation law of particle physics can be broken, and it might help explain why the universe ended up filled with matter rather than equal parts matter and antimatter.

NEXT-100

NEXT-100 is built ¹ to search for exactly this process in a specific form of xenon gas known as xenon-136. The detector holds about 70.5 kilograms of this isotope, compressed to high pressure inside a large vessel made from a radiopure titanium-steel alloy. The choice of gas is central to the whole design. When particles pass through pressurized xenon, they leave behind two simultaneous signatures: a flash of ultraviolet light and a trail of freed electrons. NEXT-100 reads both with unusual precision.

The heart of the experiment is a time projection chamber, which you can think of as a three-dimensional camera for invisible particle tracks. When a decay happens in the gas, the xenon atoms briefly light up, producing a first faint flash that marks the precise start time of the event. The freed electrons then drift slowly through the chamber under the influence of an electric field. Near one end of the vessel, they enter a narrow region where the field is strong enough to accelerate them into producing a second, much brighter burst of light, but not so strong that it triggers a chaotic avalanche. This gentle, controlled amplification, known as electroluminescence, is the key innovation of the NEXT program, because it preserves an extremely accurate measurement of the total energy deposited in the gas.

A fixed number…

That energy precision matters enormously. If neutrinoless double beta decay exists in xenon-136, it would always deposit energy at one exact value: about 2.46 million electron volts, a fixed number set by the physics of the nucleus. NEXT-100 is designed to measure energy to better than one percent precision, which allows it to pick out a genuine signal from the much broader fog of ordinary radioactive contamination that would otherwise swamp it.

…and a shape

But energy alone is not enough. The detector also records the shape of the electron tracks, and this is where things get particularly elegant. A true neutrinoless double beta decay produces two electrons that fly apart from the same point, each depositing a distinctive blob of energy at the end of its track. Most background events look quite different, typically resembling a single electron with only one such bright endpoint. By checking both the energy and the track shape simultaneously, the detector acts as a kind of double filter, rejecting far more background than either measurement could alone.

Health checks by radon

The collaboration reports that NEXT-100 has already been operating stably during its commissioning phase, first with argon and then with xenon gas. One particularly striking part of the story is how the team uses naturally occurring radioactive decays from radon, a gas that inevitably seeps into the detector in tiny amounts, as an internal health check. By tracking those decays over time, the physicists can confirm that electrons are drifting cleanly across the entire gas volume without being absorbed, a crucial requirement for the detector to work as intended.

Materials science

Another thread running through the whole project is one that might surprise you: much of particle physics turns out to be materials science. Every component of the detector, from the lead bricks forming the outer shield to the ultra-pure copper blocks lining the inside, from the plastic structural supports to the resistors shaping the electric field, has been selected or tested for extremely low levels of natural radioactivity. Even the red paint on the lead shielding had to be stripped away after it was found to contain too many radioactive contaminants during an earlier phase of the experiment. In this kind of search, a carelessly chosen bolt can generate as much unwanted background as hours of real data.

Something much bigger

What makes this experiment particularly exciting is that it is explicitly designed as a proof of concept for something much bigger. NEXT-100 aims to probe neutrinoless double beta decay half-lives on the order of ten thousand trillion trillion years, a number so large it dwarfs the age of the universe by a factor of about a trillion. If it reaches that sensitivity, and if the technology scales as the team expects, it would strengthen the case for a future ton-scale detector that could decisively test whether neutrinos are truly their own antiparticles.

So this detector is a bridge between engineering and cosmology. By watching a carefully purified volume of xenon gas deep underground, physicists are hunting for an event so rare it may happen less than once in ten thousand trillion trillion years per atom. Yet if they ever see it, the consequences would ripple through our understanding of mass, symmetry, and the cosmic origin of matter itself.

Author: César Tomé López is a science writer and the editor of Mapping Ignorance

Disclaimer: Parts of this article may have been copied verbatim or almost verbatim from the referenced research paper/s.

The post Listening for the Universe’s rarest whisper appeared first on Mapping Ignorance.

Imagine you’re in line at your favourite bakery, deciding whether to have a doughnut or a tart. You weigh them up, the doughnut wins, and you settle on that.

By the time you’re at the front of the line, however, only tarts are left. So, you buy one.

These two decisions feel completely different. One involves deliberation based on our unique and personal preferences, while the other involves simply recognising and picking the only available option.

But our latest research published in the journal Imaging Neuroscience shows our brains actually make these decisions in surprisingly similar ways.

What exactly is a free choice?

When we make free decisions, we recognise multiple options exist, weigh them up, and commit to one based on something internal: our preferences, values and goals.

Forced decisions are different. There’s only one possible outcome, and our job is simply to identify the option and take it.

Because free decisions feel so closely tied to who we are, neuroscientists have long assumed they rely on different processes in the brain compared to forced decisions. Some brain imaging studies support this, showing different patterns of neural activity distributed across the brain.

However, knowing where in the brain free choices happen tells us little about how they are formed – and whether this process is any different from forced decisions.

How does the brain form decisions?

Decades of research have shown that, to make decisions, our brains gradually gather evidence for each option over time.

Think of it like a judge evaluating the facts of a case. Once enough evidence has been accumulated in favour of one party, a verdict is reached. For some types of decisions, this happens very quickly (over hundreds of milliseconds), making it feel like the choice just popped into your head.

By measuring electrical brain activity, researchers have identified a brain signal that reflects this accumulation of evidence during simple decisions – such as judging whether a traffic light is red or green.

Like a loading bar building to 100%, the signal gradually rises to a particular level before a decision is made. Because the action of neurons in the brain is noisy, this decision-making process also occurs in a noisy fashion: rather than climbing steadily towards one option, the signal fluctuates back and forth between the alternatives.

This partly explains why we aren’t always consistent with our choices – even when our preferences are stable, some days we will go for the tart and others, the doughnut.

This signal has been identified for forced decisions with a clear correct answer. But what about choices that are open-ended – shaped not just by what’s in front of us, but by something internal like preferences or personal goals?

Tracing brain signals of decision formation

To answer this question, we recorded people’s brain activity while they chose between sets of coloured balloons. They viewed either two balloons of different colours to freely choose between, or a single balloon they were forced to pick.

They pressed a button the moment they made their choice, and we tracked how brain activity unfolded in the lead-up to that moment.

For both free and forced decisions, the brain activity unfolded in a very similar way. Like a loading bar, it climbed steadily to the same peak level just before a choice was made. When people decided quickly, the signal increased faster. When they took longer, it rose more slowly.

That’s exactly what you would expect if the brain were tracking and weighing up evidence over time, rather than simply reacting to a decision at the last moment.

Does this mean our free choices aren’t really free?

From this finding, one might assume the brain forms free and forced decisions in the same way, suggesting decision-making in the brain may be more automatic than it feels.

This echoes famous experiments by neuroscientist Benjamin Libet in the 1980s. He and colleagues found brain activity begins ramping up before people are even consciously aware of their intention to act – suggesting the brain has already begun deciding before the person consciously realises they’ve made a choice.

But while the process may be automatic, what the brain is accumulating tells a different story. The evidence it weighs up is drawn entirely from who you are – your preferences, your goals, your experiences. Two people may go through the same neural process and land on the same choice, and yet arrive there for completely different reasons.

So rather than asking whether our choices are truly free, perhaps the better question is what it really means for a choice to be yours. And the next time you find yourself in line at the bakery, know that your brain has already been quietly gathering evidence toward your baked good of choice, and that choice happens a little faster than you realise.

 

This article is republished from The Conversation under a Creative Commons license. Original article.

The post Are we ever truly free to make decisions? appeared first on Mapping Ignorance.

As global temperatures rise, the incidence of wildfires is increasing in many regions. This is mainly because higher average temperatures and changing weather conditions are drying out land and vegetation, making them more flammable. The study in Nature Climate Change shows that wildfires can break out closer to the poles than before. In some areas, the fire seasons may also double in length. This is under a medium scenario where the emissions don’t sharply increase or get cut till the end of this century.

“Our research shows that wildfires pose an ever-increasing threat to biodiversity. We find that nearly 84% of species vulnerable to wildfires will face a higher risk by the end of this century,” says Xiaoye Yang, a researcher at the University of Gothenburg and the study’s lead author.

13 climate models

Previous research into how biodiversity is affected by global climate change has mainly focused on gradual changes to habitats. Less attention has been paid to how climate-driven wildfires affect the long-term survival of plants and animals.

The research team, including Chalmers University of Technology, combined 13 climate models with a machine learning-based method to forecast changes in the wildfire burned area and the length of the fire season up to the end of this century. They then assessed how these changes affect the risk to species worldwide, based on a Red List from the IUCN (International Union for Conservation of Nature). The Red List includes 9,592 species whose survival is currently threatened by the increasing occurrence and severity of wildfires.

“Species with small ranges are particularly vulnerable. The most affected species are concentrated in South America, South Asia and Australia, and a large proportion of them are already endangered. An increase in the frequency of wildfires could push some of them closer to extinction,” says Yang.

Even species that have previously been spared from wildfires are facing a new threat, but there is a lack of research to assess how serious that threat is.

Global trends of increasing risk

The researchers calculated the increase in wildfires based on the IPCC’s various global warming scenarios. Under a moderate scenario involving a temperature rise of around 2.7 degrees compared with pre-industrial levels, the study shows that:

• The global area affected by wildfires could increase by around 9.3%
• Fire seasons could be extended by 22.8%
• Almost 84% of species vulnerable to fire will face an increased risk of wildfires

The study highlights significant regional differences. While the risk of wildfires is increasing in many parts of the world, certain regions in Africa may see a reduction in the area affected by fires due to a wetter climate in the future.

Climate action can reduce risk

The researchers also show that measures to limit emissions can significantly reduce the occurrence of wildfires. Compared with a high-emissions scenario, a future with moderate emissions could reduce the increase in species’ vulnerability to wildfires by more than 60%. Regions such as New Zealand, South America and areas near the Arctic would benefit most from reduced emissions.

“Current conservation strategies for vulnerable plants and animals risk underestimating future threats if they do not take into account disturbances such as wildfires,” says Yang.

The post Longer wildfire seasons threaten species appeared first on Mapping Ignorance.

DELTA is a 1.5-GeV synchrotron radiation source operated by the TU Dortmund University. This singular university-based facility with emphasis on research and education, offers high degree of flexibility both for user experiments and accelerator physics and technology.

Most of the world’s synchrotrons are designed to provide a continuous supply of radiation to users in a variety of scientific and industrial fields. Even though Bremsstrahlung ¹ is an inherently quantum process, synchrotron radiation of electron beams in a storage ring can be well-described as an electromagnetic wave in the frame of classical electrodynamics. In ordinary electron synchrotrons the radiated power can be calculated using the Larmor formula and its relativistic generalizations describing charged particle radiation under acceleration.

The classical electrodynamics approach for synchrotrons is based on the assumption that radiation is a continuous process, which is well modelled up to very high energies which are not attainable even in the most powerful modern accelerators. However, the discrete nature of radiation includes the recoil of an electron when it emits a photon. Also, the resulting radiation polarization depends on the electron spin. Thus, the statistical properties of photons provide additional information beyond the classical treatment to explain the stochastic emission of quanta by individual electrons.

Single-electron experiments in a storage ring allow us to study in detail the quantum nature of synchrotron light as well as to develop new technology for beam diagnostics in accelerators. To produce a single-electron beam in DELTA, a low single bunch of electron current is first injected in the storage ring and a beam scraper is used to detect and remove the beam halo. Photons emitted by electrons in a dipole magnet or an undulator can be easily detected using a photomultiplier or an avalanche photodiode. At beamline BL 4 in DELTA the single-electron beam is prepared and measured ². The main non-invasive measurement set-up is shown in Figure 1.

The setup was first tested with a moderate single-bunch electron current and a strongly attenuated beam of synchrotron radiation. The scraper is moved close to the electron beam, considering the electron period of 384ns in the ring, to drastically increase the loss rate. In Figure 2 it is shown the radiated photons per second measured in the storage ring by eliminating the last 22 electrons in the injected bunch. Each step marked in red corresponds to the loss of one electron.

The emission of a photon by a single electron at approximately every 100th passage through an undulator is completely different from the classical description. It is remarkable that, unlike typical objects to study quantum mechanical phenomena, an undulator usually extends over several meters. This may allow us to use standard accelerator techniques like radiofrequency and magnetic fields to manipulate non-classical properties.

Note for instance that the recoil gives momentum to the excitation of radial degrees of freedom of an electron when it radiates a photon. Thus, the trajectory of the electron experiments a quantum widening. The electromagnetic radiation by a charged fermion moving in an external magnetic field depends on the spin of the fermion. This effect was first proposed and computed by Sokolov and Ternov, and measurement on a storage ring to develop further QED testing and new quantum diagnostics technology for particle beams are areas of significant current interest.

The post Single-electron Bremsstrahlung in a synchrotron storage ring for quantum experiments appeared first on Mapping Ignorance.

STRAWBERRY fields

A new study ¹, charmingly named STRAWBERRY, offers a fresh answer. Instead of defining a halo by drawing an arbitrary boundary around where the matter density becomes “high enough,” the researchers ask a more physical question: which dark matter particles are truly trapped by the halo’s gravity, and which are only passing through? This may sound like a technical distinction, but it changes the way we think about cosmic structure.

Imagine a mountain valley in fog. Some hikers are clearly inside the valley, unable to leave without climbing over the ridge. Others are simply crossing nearby slopes and will soon move on. Previous methods often counted both groups together because they only looked at how crowded the area was. STRAWBERRY instead studies the shape of the gravitational “landscape” itself, identifying the valleys, the ridges between them, and the particles whose energy is too low to escape.

In practice, the team uses what they call the gravitational potential: a map of “gravitational altitude” that assigns a single number to every point in space, telling you how tightly gravity holds a particle there. A particle belongs to a halo if it does not have enough energy to cross the nearest gravitational pass that leads into a deeper neighbouring valley. This makes the halo boundary a true dynamical edge, defined by motion and energy, not by a human-chosen threshold.

Layered haloes

The most important result is conceptually beautiful. Dark matter haloes appear to be made of two distinct layers.

The inner layer is genuinely bound. These particles orbit the halo for long times, settle into a near equilibrium state, and create a structure with a real finite size. In the simulations, this bound core shows a sharp outer cutoff, meaning the halo mass naturally converges instead of fading ambiguously into space forever.

Outside it lies a second population, particles that are not truly captive. Some are falling in for the first time; others have swung around once and are splashing back outward — cosmologists call these the “splashback” population. They still contribute to the familiar extended halo profile, but physically they are part of the surrounding cosmic traffic rather than the stable heart of the halo.

A dark ecosystem

Thus, a dark matter halo is not just a fuzzy blob. It is more like a living ecosystem with a stable core and a constantly changing environment. After all, almost every major prediction in modern cosmology depends on haloes. We use them to estimate galaxy masses, model galaxy clustering, infer how structure grew after the Big Bang, and compare dark matter theories with observations. If we misunderstand what belongs to a halo, we can bias those results.

This work moves us away from bookkeeping definitions and toward a definition rooted in dynamics, energy, and fate. Instead of asking where matter happens to be dense today, it asks what matter is right now energetically bound to the structure. When astronomers compare theoretical haloes to galaxy surveys, they may now be able to separate the long-lived gravitational skeleton from the transient inflow around it. This new framework may therefore sharpen the bridge between simulations and real observations.

Author: César Tomé López is a science writer and the editor of Mapping Ignorance

Disclaimer: Parts of this article may have been copied verbatim or almost verbatim from the referenced research paper/s.

The post STRAWBERRY fields, where dark matter haloes truly end appeared first on Mapping Ignorance.

The post Why do men sexually harass women at work? appeared first on Mapping Ignorance.

The research team built their “mini-atmosphere” inside a rotating cylindrical tank: an annular ring, like a round moat, with an inner wall and an outer wall. They filled the gap with a water-glycerol mixture roughly 24 centimetres deep and spun the whole apparatus to mimic Earth’s rotation and the deflecting force it exerts on moving air. To reproduce the temperature contrast between the equator and the poles, they heated a ring of fluid at the outer base of the tank (standing in for the sun-warmed tropics) and chilled a plate pressing down on the fluid’s inner surface from above (standing in for the radiative cooling high in the polar atmosphere). Tiny tracer particles seeded in the fluid let cameras track every swirl and eddy, revealing hidden flows across a vast range of scales.

This setup is no toy. It faithfully reproduces the kind of large-scale, rotation-dominated flow (known as geostrophic turbulence) that governs planetary atmospheres and oceans. On Earth, this balance between rotation and pressure keeps high-altitude winds sweeping along pressure contours rather than blowing straight from high to low pressure. The same physics shapes Jupiter’s colourful bands and persistent storm systems, and even the meandering currents in our own oceans.

What the team discovered is striking. In classical two-dimensional turbulence theory, energy tends to flow from small eddies up into giant vortices, while the intensity of rotation (a quantity called enstrophy) cascades in the opposite direction, from large to small, eventually dissipating as heat. The lab experiment confirms this picture but adds a crucial twist: everything depends on how strongly the fluid resists vertical mixing, that is, on how stably it is layered from top to bottom. The strength of this layering, measured by how quickly a parcel of fluid would oscillate if nudged upward and released, turns out to control the overall intensity of the turbulence.

The distribution of energy across different scales of motion follows a precise mathematical relationship, dropping steeply as flows get smaller — a pattern that has been measured directly in the real atmosphere by aircraft but that many models fail to reproduce accurately. The key finding is that the strength of this pattern scales with the square of the layering intensity. In other words, the more stably stratified the fluid, the more pronounced the drop-off at large scales, and the more tightly the energy organises itself into large coherent structures.

Even more intriguing is what the team found about the direction of energy flow. Rather than a single clean cascade in one direction, they observed something more subtle: around a characteristic length scale set by the balance between rotation and stratification, the direction of energy flow reverses. Below that scale, energy moves upward to larger structures; above it, energy moves downward to smaller ones. These two directions coexist simultaneously, driven by the same instability that generates mid-latitude weather systems, the tendency of a rotating, stably layered fluid to develop eddies that tilt against the temperature gradient. Crucially, the intensity of the enstrophy cascade itself is also governed by the stratification, meaning the whole system is ultimately controlled by the vertical temperature structure of the fluid.

Atmospheric models used for weather forecasts and climate projections have long shown discrepancies when compared with global observations. Aircraft sample only narrow slices; satellites see the big picture but miss fine-scale turbulence. By providing a controlled, three-dimensional view of exactly how layering shapes these flows, the experiment gives modellers a new and independent benchmark, one that does not inherit the biases built into the models themselves. The paper points out that while models broadly reproduce the energy distribution near the tropopause, the subtler question of how energy transfers across scales, and at what length scale that transfer changes direction, is far more sensitive to how small-scale processes are approximated. That is precisely where the laboratory results offer the clearest constraint.

The implications stretch to other worlds. The paper plots the relevant parameters for Jupiter, Saturn, Earth, Mars, Titan, and Venus side by side with the experimental data, showing that the same fundamental framework applies across a remarkable range of planetary atmospheres. For gas giants like Jupiter and Saturn, whose powerful jet streams and long-lived vortices persist for centuries, the dynamics fall into a somewhat different regime — one where the jets themselves dominate — and the authors flag this as the focus of future work.

Of course, no tank can capture every complexity of a full planetary atmosphere. Chemistry, radiation, moisture, and three-dimensional convection are all absent. Yet by isolating the pure fluid dynamics, the team has delivered a precise and controlled demonstration of how stratification organises atmospheric chaos. Their work reminds us that even the most familiar sky above us still holds surprises — and that sometimes the best way to understand a planet is to build a small one on a laboratory bench.

The post Planetary atmosphere in a tank appeared first on Mapping Ignorance.

Closing the ancestry data gap

Over the past decade, scientists have identified numerous rare genetic variants that confer substantial risk for autism and other neurodevelopmental disorders. However, most of these discoveries were made in cohorts composed predominantly of individuals of European ancestry, leaving open the question of whether autism’s genetic underpinnings differ across populations. This knowledge gap has contributed to disparities in genetic testing, including higher rates of inconclusive results among non-European individuals due to limited reference data.

To address this issue, the research team analyzed exome and genome sequencing data from more than 15,000 Latin American individuals across North, Central, and South America, including approximately 4,700 individuals diagnosed with autism. Latin American populations represent the largest recent mixed-ancestry group globally, with heritage that frequently includes Indigenous American, West African, and European origins. This rich genetic diversity provides a powerful opportunity to refine gene-disease associations, which can improve health outcomes for all populations.

What the researchers looked for

The study examined more than 18,000 genes for enrichment of rare, deleterious coding variants—genetic changes that can have immediate and profound clinical implications for diagnosis, treatment, and family counseling.

Consistent with prior research, rare, deleterious variants in highly conserved genes—genes that remain similar across species and populations over long periods of time—were disproportionately observed in individuals with autism. Researchers identified 35 genes significantly associated with autism in the Latin American cohort. These genes showed extensive overlap with those previously identified in genome-wide studies of individuals of European ancestry. The findings also provide support for several recently identified “emerging” autism-associated genes.

“Our results indicate that the core genetic architecture of autism is shared across ancestries,” said study senior author Joseph D. Buxbaum, Ph.D., Director of the Seaver Autism Center for Research and Treatment at Mount Sinai. “This suggests that the biology underlying autism is universal and reinforces the importance of ensuring that diverse populations are represented in genetic research.”

Revisiting gene conservation metrics

The study also evaluated widely used metrics that assess evolutionary conservation of genes, an important tool for prioritizing genes in clinical genetic analyses of neurodevelopmental disorders. The researchers found that these metrics, which were again largely derived from European-ancestry datasets, may overestimate conservation overall due to limited ancestral diversity in European populations. However, the metrics remain highly accurate for the most strongly conserved genes—including those most relevant to autism and other neurodevelopmental disorders.

The authors note that continued sequencing of diverse populations will further improve conservation metrics, particularly for less conserved genes, ultimately enhancing the accuracy of clinical genetic testing.

“These findings provide a road map for improving genetic diagnosis across ancestral groups,” said Dr. Buxbaum. “Expanding genomic research in underrepresented populations is essential to reducing health disparities and advancing precision medicine for autism and related conditions across all ancestral populations.”

The study’s results align with growing evidence that both rare and common genetic risk factors for complex disorders are shared across diverse populations. By demonstrating broad overlap in autism risk genes across ancestries, the research supports more inclusive approaches to genomic medicine and reinforces the universal biological foundations of autism.

The post Genetic architecture of autism is consistent across diverse populations appeared first on Mapping Ignorance.