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Trees need a certain number of warm days in their growing seasons to grow properly; otherwise, the cell walls of new growth don’t lignify properly, creating blue rings that appear when wood samples are dyed.

Since trees and shrubs can live for hundreds of years, identifying these blue rings allows us to spot cold summers in the past. By looking at pine trees and juniper shrubs from northern Norway, scientists identified two extremely cold summers in 1902 and 1877, possibly caused by the eruptions of Mount Pelée on the island of Martinique and Cotopaxi in Ecuador.

“Blue rings look like unfinished growth rings, and are associated with cold conditions during the growing season,” said Dr. Agata Buchwal of Adam Mickiewicz University, Poland, lead author of the article in Frontiers in Plant Science.

Continue reading “Curious blue rings in trees and shrubs reveal cold summers of the past—potentially caused by volcanic eruptions” | >

Do speakers of different languages build sentence structure in the same way? In a neuroimaging study published in PLOS Biology, scientists from the Max Planck institute for Psycholinguistics, Donders Institute and Radboud University in Nijmegen recorded the brain activity of participants listening to Dutch stories. In contrast to English, sentence processing in Dutch was based on a strategy for predicting what comes next rather than a “wait-and-see” approach, showing that strategies may differ across languages.

While listening to spoken , people need to link abstract knowledge of grammar to the words they actually hear. Theories on how people build grammatical structure in real time are often based on English. In sentences such as “I have watched a documentary,” the noun “documentary” immediately follows the verb. However, in Dutch sentences, the may be reversed: “Ik heb een documentaire gezien” (“I have a documentary watched.”).

“To find out whether speakers of different languages build grammatical structure in the same way, it is important to look at languages that differ from English in such interesting respects,” says first author Cas Coopmans. “Findings based on English may not generalize to languages that have different grammatical properties, such as Dutch.”

Continue reading “Building sentence structure may be language-specific, brain activity study finds” | >

The experimental configuration is shown schematically in Fig. 1. Sensitive detection of the THG signal requires the use of a lowpass filter (LPF), reducing the spectral width of the pump pulse and eliminating any residual pump at the third harmonic frequency. After the generation of the THG inside the graphene-based sample, a highpass filter (HPF) is used to limit the incident pump reaching the detection scheme. Although the HPF used in our experiment does not completely eliminate the pump, it still reduces the pump-induced noise at the third harmonic frequency to a value close to the noise floor. This technique relying on a HPF significantly increases the sensitivity of time-resolved detection to monitor the creation of new spectral components24,29. The general design of these filters are described in previous work31 and their spectral transmission properties are shown in Section 2 of the Supplementary Information. In brief, the LPF transmits multicycle THz pump pulse centered at the frequency, ω = 0.8 THz, and strongly attenuates (∼ 50 dB) spectral components beyond 1.5 THz. The HPF attenuates the pump pulse by 30 dB while transmitting the third harmonic at 3ω

We investigate six nonlinear samples consisting of stacked graphene sheets, from 1 to 15 layers, allowing us to vary the nonlinear interaction length. Figure 2a shows the spectrum of the THz pulse (blue line) transmitted through the LPF and used as the pump at the fundamental frequency ω. This graph only contains spectral measurements collected with the 1-, 3-, and 6-layer graphene samples (purple, green and red lines, respectively) for enhanced clarity of the display. A distinct THG spectral peak at 3ω = 2.4 THz can be observed with an intensity increasing roughly quadratically with the number of graphene layers (see Sections 1 and 3 in the Supplementary Information). The HPF, which role is to decrease the residual pump, allows the noise level at frequencies beyond 1.5 THz to settle close to the noise floor (grey shaded area), enabling sensitive monitoring of the nonlinear effects. Figure 2b shows the time-resolved multicycle pump pulse (blue line) with a peak amplitude of 32 kV/cm.

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Phonons, the quantum mechanical vibrations of atoms in solids, are often sources of noise in solid-state quantum systems, including quantum technologies, which can lead to decoherence and thus adversely impact their performance.

Strategies to reliably control phonons and their interactions with quantum systems could help to mitigate the adverse effects of these vibrations on the systems.

Researchers at Harvard University and other institutes have introduced a new approach to control the interactions between high-frequency phonons and single solid-state quantum systems. Their proposed method, outlined in a paper published in Nature Physics, relies on new diamond phononic crystals that they designed and fabricated, which can be used to engineer the local density of states in a host material.

Continue reading “Newly fabricated crystals control interactions between high-frequency phonons and single quantum systems” | >

Microscale light-emitting diodes (micro-LEDs) are emerging as a next-generation display technology for optical communications, augmented and virtual reality, and wearable devices. Metal-halide perovskites show great potential for efficient light emission, long-range carrier transport, and scalable manufacturing, making them potentially ideal candidates for bright LED displays.

However, manufacturing thin-film perovskites suitable for micro-LED displays faces serious challenges. For example, thin-film perovskites may exhibit inhomogeneous light emission, and their surfaces may be unstable when subjected to lithography. For these reasons, solutions are needed to make thin-film perovskites compatible with micro-LED devices.

Recently, a team of Chinese researchers led by Professor Wu Yuchen at the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences has made significant strides in overcoming these challenges. The team has developed a novel method for the remote epitaxial growth of continuous crystalline perovskite thin films. This advance allows for seamless integration into ultrahigh-resolution micro-LEDs with pixels less than 5 μm.

Continue reading “Plastic supercapacitors could solve energy storage problems” | >

It’s become increasingly clear that the gut microbiome can affect human health, including mental health. Which bacterial species influence the development of disease and how they do so, however, is only just starting to be unraveled.

For instance, some studies have found compelling links between one species of gut bacteria, Morganella morganii, and major depressive disorder. But until now, no one could tell whether this bacterium somehow helps drive the disorder, the disorder alters the microbiome, or something else is at play.

Harvard Medical School researchers have now pinpointed a biologic mechanism that strengthens the evidence that M. morganii influences brain health and provides a plausible explanation for how it does so.

Continue reading “Drawing a line from the gut microbiome to inflammation and depression” | >

A team of chemists and agriculture specialists has developed a way to transform urea in wastewater, into percarbamide, which can be used as a fertilizer. In their paper published in the journal Nature Catalysis, the group describes their process and how well the resulting product worked in growing edible crops.

Urine is seen as a source of because it is high in nitrogen and other rich compounds that are good for . Many home gardeners know that urine can be used as a fertilizer both for flower and vegetable gardens—the key is to mix it with a lot of water to prevent burning the plants.

Prior efforts to use urine as a source of fertilizer on a larger scale, however, have proven to be unfeasible due to industrial inefficiencies; it is much easier to use standard methods that involve extracting nitrogen from the air. In this new effort, the researchers have developed a way to use human and animal as a fertilizer for growing edible crops.

Continue reading “Innovative process converts urine into slow-release crystal fertilizer” | >

Surprise is a key human emotion that is typically felt when something that we are witnessing or experiencing differs from our expectations. This natural human response to the unexpected has been the focus of numerous psychology studies, which uncovered some of its underlying neural processes.

Researchers at the University of Chicago have developed a brain network model that can predict people’s surprise. In a paper published in Nature Human Behaviour, they showed that this model generalized well across various tasks, predicting the surprise of individuals who were performing a task or watching different videos containing unexpected elements.

The study carried out by these researchers builds on previous research focusing on surprise. Earlier work found that humans experience surprise when reality clashes with their expectations in many different situations. Some of these past works discovered patterns of brain activity associated with each specific experience of surprise.

Continue reading “Brain network model can predict when people will feel surprised” | >

Ferroelectrics at the nanoscale exhibit a wealth of polar and sometimes swirling (chiral) electromagnetic textures that not only represent fascinating physics, but also promise applications in future nanoelectronics. For example, ultra-high-density data storage or extremely energy-efficient field-effect transistors. However, a sticking point has been the stability of these topological textures and how they can be controlled and steered by an external electrical or optical stimulus.

A team led by Prof. Catherine Dubourdieu (HZB and FU Berlin) has now published a paper in Nature Communications that opens up new perspectives. Together with partners from the CEMES-CNRS in Toulouse, the University of Picardie in Amiens and the Jozef Stefan Institute in Ljubljana, they have thoroughly investigated a particularly interesting class of nanoislands on silicon and explored their suitability for electrical manipulation.

“We have produced BaTiO3 nanostructures that form tiny islands on a silicon substrate,” explains Dubourdieu. The nano-islands are trapezoidal in shape, with dimensions of 30–60 nm (on top), and have stable polarization domains.

Continue reading “Nanoislands on silicon enable switchable topological textures for new electronic applications” | >

In a pioneering approach to achieve fusion energy, the SMART device has successfully generated its first tokamak plasma. This step brings the international fusion community closer to achieving sustainable, clean, and virtually limitless energy through controlled fusion reactions.

The work is published in the journal Nuclear Fusion.

The SMART tokamak, a state-of-the-art experimental fusion device designed, constructed and operated by the Plasma Science and Fusion Technology Laboratory of the University of Seville, is a unique spherical tokamak due to its flexible shaping capabilities. SMART has been designed to demonstrate the unique physics and engineering properties of Negative Triangularity shaped plasmas towards compact fusion power plants based on Spherical Tokamaks.

Continue reading “SMART: One step closer to nuclear fusion with its first plasma” | >