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At room temperature, metal-free organic molecules demonstrate strong phosphorescence

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A metal-free organic 3-bromo-2-thienyl diketone exhibits fast and efficient room-temperature phosphorescence with high color purity under a variety of conditions, according to a new study led by chemists at Osaka University.

Artist's impression of fast phosphorescence. A beam of blue light enters the molecule, producing a thick yellow pillar, illustrating the acceleration of phosphorescence due to the mixing of singlet states. Image courtesy of YAP Co Ltd.

“Phosphorescence is a valuable optical feature used in applications such as OLEDs and cancer diagnostics,” said chemist Yosuke Tani of Osaka University and his colleagues.

“Until now, achieving highly efficient phosphorescence without using rare metals such as iridium or platinum has been a major challenge.”

“Phosphorescence, which occurs when a molecule goes from a high-energy state to a low-energy state, often competes with non-radiative processes where the molecule loses energy as heat,” the researchers added.

“This competition can slow down phosphorescence and make it less efficient.”

“Previous studies have shown that incorporating certain structural elements into organic molecules could make them phosphoresce faster, but these efforts have not matched the speed and efficiency of rare-metal-based materials.”

“Our breakthrough with thienyl diketones represents a major advance in this field.”

Dr. Tani and his co-authors were able to observe efficient narrowband room-temperature phosphorescence from 3-bromo-2-thienyl diketone in solution, amorphous polymer matrices, and crystalline solids.

“We discovered these molecules by chance and initially didn't understand why they performed so well,” Dr. Tani said.

“But as the research progressed, the pieces started to come together and we began to understand more.”

“Our work has led to a clearer understanding of the mechanisms behind the molecule's performance than any other organic phosphorescent material to date.”

“Still, we believe there is much more to explore and are excited about the potential applications.”

“This work provides new design guidelines for developing rare-metal-free organic phosphorescent materials, which have the potential to surpass and replace these materials in a variety of applications,” the authors conclude.

“The results of this research are expected to lead to major advances in areas such as OLEDs, lighting and medical diagnostics.”

This discovery paper In the journal Chemical Sciences.

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Yosuke Tani othersFast and efficient narrowband room-temperature phosphorescence from metal-free 1,2-diketones: rational design and mechanism. Chemical SciencesPublished online June 3, 2024; doi: 10.1039/D4SC02841D

Source: www.sci.news

Fruit bats demonstrate episodic memory and mental time travel capabilities, study reveals

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Episodic memory and mental time travel have been considered uniquely human traits. This view has begun to change with the development of behavioral criteria to assess what is called episodic memory in animals. Key findings range from evidence of “what, where, when” memory in jays, mice and bees to episodic memory and future-oriented behavior in wild, free-foraging animals. In a new study, scientists investigated episodic memory and future-oriented behavior in wild, free-foraging animals. Egyptian fruit bat (Rusetus aegyptiacus)The team found that fruit bats rely on mental time maps to display future-oriented behaviour when foraging, and that time-mapping ability requires experience and is lacking in inexperienced bats.

Egyptian fruit bat (Rusetus aegyptiacus) track tree phenology and estimate fruit availability since their previous visit. Bats exhibit future-oriented behavior, flying to trees rich in specific proteins, while flying past many familiar sugar-rich trees. Young bats must learn tree phenology through experience. Image courtesy of Harten others., doi:10.1016/j.cub.2024.05.046.

“For many years, the cognitive abilities to recall and plan personal experiences (episodic memory) have been thought to be uniquely human,” Tel Aviv University.

“However, a growing body of research suggests that various animals also have such abilities, although nearly all of these studies have been carried out in laboratory settings, as field studies on this issue are difficult to conduct.”

“To test these capabilities in wildlife, we designed a unique experiment using a wild colony of flying foxes.”

The researchers surmised that bats that depend on fruit trees for survival need to develop the ability to track food availability both spatially (where are the fruit trees?) and temporally (when does each tree bear fruit?).

As you navigate a landscape with numerous fruit and nectar trees, you'll need to mentally keep track of resources in order to revisit them at the right time.

To test this hypothesis, they fitted each bat with a small, high-resolution GPS tracker, allowing them to record their flight routes and the trees they visited over several months.

The vast amount of data collected in this way was thoroughly analyzed, yielding surprising results.

“Our first research question was: do bats form mental maps of time?” says Dr Lee Harten from Tel Aviv University.

“To investigate this issue, we confined bats to their colonies for various periods of time, ranging from one day to a week.”

“We wanted to see if the bats would recognise that time had passed and behave accordingly.”

“We found that after one day in captivity, the bats would return to the trees they had visited the previous night. But after a full week, the older bats, based on their past experience, began to avoid trees that had stopped bearing fruit in the meantime.”

“In other words, they could estimate how much time had passed since they last visited each tree, and thus know which trees only bore fruit for a short time and were no longer worth visiting.”

“Younger, inexperienced bats were unable to do this, suggesting that this is an acquired skill that must be mastered.”

“The first research question was about past experience, but the second question was about the future. Do bats exhibit future-oriented behavior? Can they plan for the future?”

“To address this issue, the researchers observed the route each bat took to reach the first tree in the evening, which could indicate a plan made before leaving the colony.”

“We found that bats usually fly directly to specific trees they know, sometimes up to 20-30 minutes away,” said Dr Chen Xin from Tel Aviv University.

“They're hungry, so they fly faster the further away the trees are, which suggests they're planning where they're going.”

“Furthermore, because they are so focused on their chosen target, they pass by other trees and even good sources of information that they only visited yesterday, demonstrating their ability to postpone gratification.”

“We also found that the first bats to leave the colony chose trees with fruits high in sugar, while those who left later sought out fruits with protein.”

The findings suggest that bats plan their foraging before they leave the colony, knowing exactly where they'll be flying and what nutrients they'll be looking for.

“The gap between human and animal cognition is one of the most fascinating questions in science,” Professor Yobel said.

“Our study demonstrates that flying foxes are able to carry out highly complex decision-making processes involving three questions that demonstrate cognitive capabilities: 'where?' (the location of each tree), 'when?' (when the trees will bear fruit) and 'what?' (what nutrients the trees provide, sugars or proteins).”

“Once again, the gap wasn't clearly carved out, and we find that humans are not as special as some think.”

“Apparently, humans and animals all lie on a spectrum, and almost all human abilities can also be found in animals.”

a paper The findings were published in the journal. Current Biology.

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Lee Harten othersTime mapping and future-oriented behavior in free-ranging wild fruit bats. Current BiologyPublished online June 20, 2024; doi: 10.1016/j.cub.2024.05.046

This article is a version of a Tel Aviv University press release.

Source: www.sci.news

Photos demonstrate the utilization of AI to reinterpret ancient graffiti

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Reinterpretation of etching

Matthew Attard and Galeria Michela Rizzo

Maltese artists at the 60th Venice Biennale Matthew Attard Through the prism of AI-driven technology, we address our nation's maritime heritage, along with concepts of faith and progress. His work focuses on images of ships graffitied by sailors on the stone facades of Maltese chapels from the 16th century to his 19th century, one of his is pictured below.

Boat graffiti in the Chapel of the Visitation of Our Lady in Weed Kilda, Malta

Elise Tonna

Attard, pictured below, used his line of sight to follow notches in the ship's hull, rigging, and billowing sails, a process facilitated by line-of-sight trackers and generative algorithms. “This line of sight was converted by technology into data points, which were further interpreted to produce lines and drawings,” he says.

A database of digital images generated from the data points captured the sculpture from different perspectives, from which works of art such as 3D scans and video works were created.

Matthew Attard wearing an eye tracking device.

Elise Tonna

Marine graffiti resonates with cultures where the relationship with the sea has been and continues to be important, and ships remain a metaphor for hope and survival. Similarly, the Maltese chapels have long been sanctuaries. Attard said he wanted to explore “parallels to the current 'blind faith' in digital technology.”

A reinterpretation of his etching is the impression of a ghostly skeleton, as shown in the main image. “Some would argue that even the most traditional mediums, such as pencil or charcoal, can be considered a form of drawing technique,” he points out. His exhibition, commissioned by the Malta Arts Council, will run at the Malta Pavilion at the Venice Biennale in Italy until 24 November.

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Source: www.newscientist.com

Mathematicians conclusively demonstrate Bach’s greatness as a composer

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According to information theory, Johann Sebastian Bach was a great composer

Granger Collection / Alamy Stock Photo

Johann Sebastian Bach is considered one of the great composers of Western classical music. Researchers are currently trying to find out why by analyzing his music using information theory.

Suman Kulkarni Researchers at the University of Pennsylvania wanted to understand how the ability to recall and predict music is related to its structure. They decided to analyze Bach's works because he produced a huge number of works with a variety of structures, including religious hymns called chorales and the fast-paced masterpiece Toccata.

First, the researchers transformed each configuration into an information network by representing each note as a node and each transition between notes as an edge and connecting them. Using this network, we compared the amount of information in each work. Intended to entertain and surprise, toccatas contain more information than chorales, which are composed for more contemplative settings such as churches.

Kulkarni and her colleagues also used information networks to compare listeners' perceptions of Bach's music. They started with an existing computer model based on an experiment in which participants responded to a series of images on a screen. The researchers then measured how surprising the elements of the array were. They adapted an information network based on this model to music, where the links between each node are used to determine how likely a listener thinks two connected notes are to be played in succession, or how likely they actually are. It expresses how surprised you would be if that happened to you. Because humans don't learn information perfectly, a network that shows people's estimated sonic changes to a song is unlikely to accurately match a network based directly on that song. Researchers can quantify that discrepancy.

In this case, the discrepancy is low, suggesting that Bach's works convey information fairly effectively. But Kulkarni wants to fine-tune computer models of human perception to better match actual brain scans of people listening to music.

“More than just knowing frequencies, neuroscience has the missing link between complex structures like music and the brain's response to them. [of sounds]. This study could provide an exciting step forward.” randy mackintosh At Simon Fraser University, Canada. However, there are many other factors that influence how a person perceives music. For example, how long the person listens to songs, whether they have musical training, etc. These still need to be explained, he says.

Even in information theory, it is still not clear whether Bach's compositional style was exceptional compared to other types of music. McIntosh said his own previous research has found some general similarities between the musicians, similar to the differences between Bach and rock guitarist Eddie Van Halen, but more detailed analysis is needed. It states that.

“I would like to perform the same analysis for different composers and non-Western music,” Kulkarni says.

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Source: www.newscientist.com