alternative_right shares a report from Phys.org: Now, for the first time, quantum scientists at the Quantum Control Laboratory at the University of Sydney Nano Institute have demonstrated a type of quantum logic gate that drastically reduces the number of physical qubits needed for its operation. To do this, they built an entangling logic gate on a single atom using an error-correcting code nicknamed the "Rosetta stone" of quantum computing. It earns that name because it translates smooth, continuous quantum oscillations into clean, digital-like discrete states, making errors easier to spot and fix, and importantly, allowing a highly compact way to encode logical qubits. The curiously named Gottesman-Kitaev-Preskill (GKP) code has for many years offered a theoretical possibility for significantly reducing the physical number of qubits needed to produce a functioning "logical qubit." Albeit by trading efficiency for complexity, making the codes very difficult to control. Research published in Nature Physics demonstrates this as a physical reality, tapping into the natural oscillations of a trapped ion (a charged atom of ytterbium) to store GKP codes and, for the first time, realizing quantum entangling gates between them. Led by Sydney Horizon Fellow Dr. Tingrei Tan at the University of Sydney Nano Institute, scientists have used their exquisite control over the harmonic motion of a trapped ion to bridge the coding complexity of GKP qubits, allowing a demonstration of their entanglement. "Our experiments have shown the first realization of a universal logical gate set for GKP qubits," Dr. Tan said. "We did this by precisely controlling the natural vibrations, or harmonic oscillations, of a trapped ion in such a way that we can manipulate individual GKP qubits or entangle them as a pair." [...] Across three experiments described in the paper, Dr. Tan's team used a single ytterbium ion contained in what is known as a Paul trap. This uses a complex array of lasers at room temperature to hold the single atom in the trap, allowing its natural vibrations to be controlled and utilized to produce the complex GKP codes. This research represents an important demonstration that quantum logic gates can be developed with a reduced physical number of qubits, increasing their efficiency.

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Reviewers are more likely to approve a manuscript if their own work is cited in subsequent versions than are reviewers who are not cited, according to an analysis of 18,400 articles from four open-access publications. From a report: The study, which is yet to be peer reviewed, was posted online as a preprint earlier this month. The study was inspired by anecdotes from authors who cited articles only because reviewers asked them to, says study author Adrian Barnett, who researches peer review and meta-research at Queensland University of Technology in Brisbane, Australia. Sometimes, these requests are fine, he says. But if reviewers ask for too many citations or the reason to cite their work is not justified, the peer-review process can become transactional, says Barnett. Citations increase a researcher's h-index, a metric reflecting the impact of their publications.

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An anonymous reader quotes a report from Reuters: Serbian scientists have been experimenting with mealworms as a way to break down polystyrene. Larisa Ilijin, a principal research fellow at Belgrade's Institute for Biology, said the scientists had discovered that mealworms can digest various plastics, including polystyrene, which is used in packaging, insulation and food containers. In the project endorsed by the government and the United Nations' agency for international development, UNDP, and other international donors, they have been including the polystyrene in the regular food of the larval form of the yellow mealworm beetle, or Tenebrio molitor. They habitually eat more or less anything, but need the training to eat the plastic products. "We have larvae that have been adapted over a long time to biodegrade plastic, to be as efficient as possible in the process," Ilijin told Reuters. She said the bacteria living in their guts break down the plastic into carbon dioxide and water, and showed no evidence of leaving microplastic residue in their innards or faeces. The work builds on similar research projects in the U.S. and Africa. [...] The institute has given Belgrade-based Belinda Animals several containers of the mealworms. It is now breeding them and hoping to attract a network of similar farms. "When breaking down 1 kg of Styrofoam, larvae emit one to two grams of carbon dioxide ... If we incinerate it ... (Styrofoam) emits over 4,000 times more," owner Boris Vasiljev said. He also envisages the larvae being used as animal feed, should it reach a large commercial scale. The use of mealworms is still in its infancy, Ilijin said, as Serbia still needs to adopt regulations that would allow the use and sale of insect products for animal fodder. "Styrofoam takes over 500 years to decompose in nature ... this would be one of the good ways for solving the problem of plastic waste in nature," Ilijin said.

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A new review of nearly 700 studies on portable air cleaners found that over 90% of them were tested in empty spaces, not on people, leaving major gaps in evidence about whether these devices actually prevent infections or if they might even cause harm by releasing chemicals like ozone or formaldehyde. The Conversation reports: Many respiratory viruses, such as COVID-19 and influenza, can spread through indoor air. Technologies such as HEPA filters, ultraviolet light and special ventilation designs -- collectively known as engineering infection controls -- are intended to clean indoor air and prevent viruses and other disease-causing pathogens from spreading. Along with our colleagues across three academic institutions and two government science agencies, we identified and analyzed every research study evaluating the effectiveness of these technologies published from the 1920s through 2023 -- 672 of them in total. These studies assessed performance in three main ways: Some measured whether the interventions reduced infections in people; others used animals such as guinea pigs or mice; and the rest took air samples to determine whether the devices reduced the number of small particles or microbes in the air. Only about 8% of the studies tested effectiveness on people, while over 90% tested the devices in unoccupied spaces. We found substantial variation across different technologies. For example, 44 studies examined an air cleaning process called photocatalytic oxidation, which produces chemicals that kill microbes, but only one of those tested whether the technology prevented infections in people. Another 35 studies evaluated plasma-based technologies for killing microbes, and none involved human participants. We also found 43 studies on filters incorporating nanomaterials designed to both capture and kill microbes -- again, none included human testing.

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Si vous ne connaissez pas cette série d'animation sur la science, foncez !  C'est scientifiquement exacte et très drôle.
(Il faudra que je prenne le temps de tout télécharger pour ne pas perdre ça.)
(Permalink)

Sunlight becomes energy when plants convert four photons of light. But unfortunately, most attempts at synthetic light-absorbing chemicals can only absorb one photon at a time, write two researchers from the University of Melbourne. "In the Polyzos research group at the School of Chemistry, we have developed a new class of photocatalysts that, like plants, can absorb energy from multiple photons." This breakthrough allows us to harness light energy more effectively, driving challenging and energy-demanding chemical reactions. We have applied this technology to generate carbanions — negatively charged carbon atoms that serve as crucial building blocks in the creation, or synthesis, of carbon- and hydrogen-rich chemicals known as organic chemicals. Carbanions are vital in making drugs, polymers and many other important materials. However, traditional methods to produce carbanions often require lots of energy and dangerous reagents, and generate significant chemical waste, posing environmental and safety challenges... Our new method offers a greener, safer alternative [using visible light and renewable starting materials]... We've used it to synthesize important drug molecules, including antihistamines, in a single step using simple, cheap and commonly available "commodity chemicals" — amines and alkenes. And importantly, the reaction scales well in commercial-scale continuous flow reactors, highlighting its potential for industrial applications. "By learning from the subtle mastery of photosynthesis," the researchers write, their group "is forging a new paradigm for chemical manufacturing — one where sunlight powers sustainable and elegant solutions for the molecules that shape our world."

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New research suggests exposure to some common Pfas or "forever chemical" compounds causes changes to gene activity, and those changes are linked to health problems including multiple cancers, neurological disorders and autoimmune disease. From a report: The findings are a major step toward determining the mechanism by which the chemicals cause disease and could help doctors identify, detect and treat health problems for those exposed to Pfas before the issues advance. The research may also point toward other diseases potentially caused by Pfas that have not yet been identified, the authors said. The study is among the first to examine how Pfas chemicals impact gene activity, called epigenetics. "This gives us a hint as to which genes and which Pfas might be important," said Melissa Furlong, a University of Arizona College of Public Health Pfas researcher and study lead author.

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A countrywide study of smartphone users who relocated between US cities found that moving to more walkable environments increased daily walking by 1,100 steps on average. Stanford University researchers analyzed 248,266 days of step data from 5,424 users of the Azumio Argus smartphone app who relocated 7,447 times among 1,609 cities between March 2013 and February 2016. Participants who moved from cities at the 25th percentile of walkability to those at the 75th percentile sustained the increased activity levels for at least three months after relocation. The additional steps consisted predominantly of moderate-to-vigorous physical activity, with large walkability increases of 49-80 points associated with about one hour per week more of such activity. The study found that 42.5% of participants met national physical activity guidelines for moderate-to-vigorous activity after moving to highly walkable locations, compared to 21.5% before relocation. Computer simulations based on the data suggest that increasing all US cities to the walkability level of Chicago or Philadelphia could result in 36 million more Americans meeting aerobic physical activity guidelines.

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An anonymous reader quotes a report from MIT Technology Review: Physicists have created a new type of radar that could help improve underground imaging, using a cloud of atoms in a glass cell to detect reflected radio waves. The radar is a type of quantum sensor, an emerging technology that uses the quantum-mechanical properties of objects as measurement devices. It's still a prototype, but its intended use is to image buried objects in situations such as constructing underground utilities, drilling wells for natural gas, and excavating archaeological sites. [...] The glass cell that serves as the radar's quantum component is full of cesium atoms kept at room temperature. The researchers use lasers to get each individual cesium atom to swell to nearly the size of a bacterium, about 10,000 times bigger than the usual size. Atoms in this bloated condition are called Rydberg atoms. When incoming radio waves hit Rydberg atoms, they disturb the distribution of electrons around their nuclei. Researchers can detect the disturbance by shining lasers on the atoms, causing them to emit light; when the atoms are interacting with a radio wave, the color of their emitted light changes. Monitoring the color of this light thus makes it possible to use the atoms as a radio receiver. Rydberg atoms are sensitive to a wide range of radio frequencies without needing to change the physical setup... This means a single compact radar device could potentially work at the multiple frequency bands required for different applications. [Matthew Simons, a physicist at the National Institute of Standards and Technology (NIST), who was a member of the research team] tested the radar by placing it in a specially designed room with foam spikes on the floor, ceiling, and walls like stalactites and stalagmites. The spikes absorb, rather than reflect, nearly all the radio waves that hit them. This simulates the effect of a large open space, allowing the group to test the radar's imaging capability without unwanted reflections off walls.The researchers placed a radio wave transmitter in the room, along with their Rydberg atom receiver, which was hooked up to an optical table outside the room. They aimed radio waves at a copper plate about the size of a sheet of paper, some pipes, and a steel rod in the room, each placed up to five meters away. The radar allowed them to locate the objects to within 4.7 centimeters. The team posted a paper on the research to the arXiv preprint server in late June.

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Researchers at Kyushu University have developed a solid-oxide fuel cell that operates at just 300C, less than half the usual operating temperature. The team was able to do this by engineering a "ScO6 highway" in the electrolyte, allowing protons to move quickly without losing performance. "The team expects that their new findings will lead to the development of low-cost, low-temperature SOFCs and greatly accelerate the practical application of these devices," said the researchers in a press release. Interesting Engineering reports: "While SOFCs are promising due to their high efficiency and long lifespan, one major drawback is that they require operation at high temperatures of around 700-800C (1292F-1472F)," added the researchers in a press release. Such heat requires costly, specialized heat-resistant materials, making the technology expensive for many applications. A lower operating temperature is expected to reduce these manufacturing costs. The team's success comes from re-engineering the fuel cell's electrolyte, the ceramic layer that transports protons (hydrogen ions) to generate electricity. Previously, scientists faced a trade-off. Adding chemical dopants to an electrolyte increases the number of available protons but also tends to clog the material's crystal lattice, slowing proton movement and reducing performance. The Kyushu team worked to resolve this issue. "We looked for oxide crystals that could host many protons and let them move freely -- a balance that our new study finally struck," stated Yamazaki. They found that by doping two compounds, barium stannate (BaSnO3) and barium titanate (BaTiO3), with high concentrations of scandium (Sc), they could create an efficient structure. Their analysis showed that the scandium atoms form what the researchers call a "ScO6 highway." This structure creates a wide and softly vibrating pathway through the material. "This pathway is both wide and softly vibrating, which prevents the proton-trapping that normally plagues heavily doped oxides," explained Yamazaki. The resulting material achieves a proton conductivity of more than 0.01 S/cm at 300C, a performance level comparable to conventional SOFC electrolytes that run at more than double the temperature. The research has been published in the journal Nature Materials.

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People who experience nightmares weekly or more frequently face three times higher risk of dying before age 70 compared to those having nightmares less than monthly, according to research by Dr. Abidemi Otaiku at Imperial College London. His analysis of six long-term studies covering more than 180,000 adults and 2,500 children found frequent nightmares predict early death more strongly than smoking, obesity, poor diet, or physical inactivity. Among 174 people who died prematurely, 31 experienced at least weekly nightmares. Otaiku's research shows chromosomes of nightmare-prone individuals display accelerated aging patterns linked to stress hormones, accounting for roughly 40% of their increased mortality risk. Effective nightmare treatment options are currently limited and require more medical research, the report adds.

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Computer scientists at Tsinghua University and Stanford have developed an algorithm that surpasses a fundamental speed limit that has constrained network pathfinding calculations since 1984. The team's approach to the shortest-path problem -- finding optimal routes from one point to all others in a network -- runs faster than Dijkstra's 1956 algorithm and its improvements by avoiding the sorting process that created the decades-old computational barrier. Led by Ran Duan at Tsinghua, the researchers combined clustering techniques with selective application of the Bellman-Ford algorithm to identify influential nodes without sorting all paths by distance. The algorithm divides graphs into layers and uses Bellman-Ford to locate key intersection points before calculating paths to other nodes. The technique works on both directed and undirected graphs with arbitrary weights, solving a problem that stymied researchers after partial breakthroughs in the late 1990s and early 2000s applied only to specific weight conditions.

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alternative_right shares a report from Phys.org: Three nano-glass spheres cling to one another. They form a tower-like cluster, similar to when you pile three scoops of ice cream on top of one another -- only much smaller. The diameter of the nano cluster is ten times smaller than that of a human hair. With the help of an optical device and laser beams, researchers at ETH Zurich have succeeded in keeping such objects almost completely motionless in levitation. This is significant when it comes to the future development of quantum sensors, which, together with quantum computers, constitute the most promising applications of quantum research. As part of their levitation experiment, the researchers, led by adjunct professor of photonics Martin Frimmer, were able to eliminate the gravitational force acting on the glass spheres. However, the elongated nano object still trembled, similar to how the needle on a compass moves when settling into position. In the case of the nano cluster, the trembling motion was very fast but weak: the object made around one million deflections per second, each measuring only a few thousandths of a degree. This tiny rotational oscillation is a fundamental quantum motion exhibited by all objects, which physicists call zero-point fluctuation. To date, no one has been successful in detecting these tiny movements for an object of this size as precisely as the ETH researchers have now done. They achieved this because they were able to largely eliminate all motions that originate from the field of classical physics and obscure the observation of quantum movements. The ETH researchers attribute 92% of the cluster's movements in their experiment to quantum physics and 8% to classical physics; they therefore refer to a high level of quantum purity. And the records do not stop there: The researchers accomplished all of this at room temperature. Quantum researchers usually have to cool their objects to a temperature close to absolute zero (-273 degrees Celsius) using special equipment. This was not required here. The research has been published in the journal Nature Physics.

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Nearly one-third of all retracted papers at PLoS ONE can be traced back to just 45 researchers who served as editors at the journal, an analysis of its publication records has found. Nature: The study, published in Proceedings of the National Academy of Sciences (PNAS), found that 45 editors handled only 1.3% of all articles published by PLoS ONE from 2006 to 2023, but that the papers they accepted accounted for more than 30% of the 702 retractions that the journal issued by early 2024. Twenty-five of these editors also authored papers in PLoS ONE that were later retracted. The PNAS authors did not disclose the names of any of the 45 editors. But, by independently analysing publicly available data from PLoS ONE and the Retraction Watch database, Nature's news team has identified five of the editors who handled the highest number of papers that were subsequently retracted by the journal. Together, those editors accepted about 15% of PLoS ONE's retracted papers up to 14 July.

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For years, whistle-blowers have warned that fake results are sneaking into the scientific literature at an increasing pace. A new statistical analysis backs up the concern. From a report: A team of researchers found evidence of shady organizations churning out fake or low-quality studies on an industrial scale. And their output is rising fast, threatening the integrity of many fields. "If these trends are not stopped, science is going to be destroyed," said LuÃs A. Nunes Amaral, a data scientist at Northwestern University and an author of the study, which was published in the Proceedings of the National Academy of Sciences on Monday. Science has made huge advances over the past few centuries only because new generations of scientists could read about the accomplishments of previous ones. Each time a new paper is published, other scientists can explore the findings and think about how to make their own discoveries. Fake scientific papers produced by commercial "paper mills" are doubling every year and a half, according to the report. Northwestern University researchers examined over one million papers and identified networks of fraudulent studies sold to scientists seeking to pad their publication records. The team estimates the actual scope of fraud may be 100 times greater than currently detected cases. Paper mills charge hundreds to thousands of dollars for fake authorship and often target specific research fields like microRNA cancer studies.

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Slashdot reader ffkom writes: The air around you mostly consists of nitrogen [78%]. And in that air exist happy little monogamous pairs of two nitrogen atoms per molecule, also known as N2. Researchers from the University of Giessen, Germany, recently managed to synthesize N6 molecules, "the first, to our knowledge, experimentally realized neutral molecular nitrogen allotrope beyond N2 that exhibits unexpected stability." And these appear to be pretty angry little molecules, as they detonate at more than twice the energy density than good old TNT: A kiloton of N6 is 1.19×10**7mol, which can release an energy of 2.20×109kcal (9.21terajoules) based on the enthalpy. Considering that the standard kiloton TNT equivalent is 4.184terajoules, N6 can release 2.2 times the energy of TNT of the same weight. On the basis of the documented TNT equivalent based on weight for HMX (1.15) and RDX (1.15), N6 can release 1.9 times the energy of HMX or RDX with the same weight. In interviews the researchers contemplated the possibility of using N6 as rocket fuel, given its superior energy density and that its reaction product is just N2, so basically air, but no smoke, no CO2 or other potentially harmful substances.

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India's national university ranking will start penalizing institutions if a sizable number of papers published by their researchers are retracted -- a first for an institutional ranking system. Nature: The move is an attempt by the government to address the country's growing number of retractions due to misconduct. Many retractions correct honest mistakes in the literature, but others arise because of misconduct. India has had more papers retracted than any country apart from China and the United States, according to an analysis of the public database maintained by Retraction Watch of retractions over the past three decades. But whereas less than 1 paper is retracted for every 1,000 papers published in the United States, more than 3 are retracted for every 1,000 published in China, and the figure is 2 per 1,000 in India. The majority in India and China are withdrawn because of misconduct or research-integrity concerns.

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alternative_right shares a report from Phys.org: Researchers have created a microphone that listens with light instead of sound. Unlike traditional microphones, this visual microphone captures tiny vibrations on the surfaces of objects caused by sound waves and turns them into audible signals. In the journal Optics Express, the researchers describe the new approach, which applies single-pixel imaging to sound detection for the first time. Using an optical setup without any expensive components, they demonstrate that the technique can recover sound by using the vibrations on the surfaces of everyday objects such as leaves and pieces of paper. [...] To demonstrate the new visual microphone, the researchers tested its ability to reconstruct Chinese and English pronunciations of numbers as well as a segment from Beethoven's Fur Elise. They used a paper card and a leaf as vibration targets, placing them 0.5 meters away from the objects while a nearby speaker played the audio. The system was able to successfully reconstruct clear and intelligible audio, with the paper card producing better results than the leaf. Low-frequency sounds (1 kHz) showed slight distortion that improved when a signal processing filter was applied. Tests of the system's data rate showed it produced 4 MB/s, a rate sufficiently low to minimize storage demands and allow for long-term recording. "Currently, this technology still only exists in the laboratory and can be used in special scenarios where traditional microphones fail to work," said research team leader Xu-Ri Yao from Beijing Institute of Technology in China. "We aim to expand the system into other vibration measurement applications, including human pulse and heart rate detection, leveraging its multifunctional information sensing capabilities."

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Brazil has launched a massive program to release millions of laboratory-bred mosquitoes engineered to carry Wolbachia bacteria, which prevents them from transmitting dengue virus. The initiative aims to protect 140 million Brazilians across 40 municipalities over the next decade. The approach has already demonstrated significant results in Niteroi, where officials documented a roughly 90% drop in dengue cases when comparing the 10 years prior to the modified mosquitoes' introduction to the five years afterward. Nearly all mosquitoes in the city now carry the Wolbachia bacteria. Cases of chikungunya and Zika also fell by over 96% and 99% respectively. The World Mosquito Program operates high-tech breeding facilities, including one in Rio de Janeiro that produces mosquitoes by the millions. A new factory in Curitiba will produce 5 billion mosquitoes in its first year. The Wolbachia bacteria, naturally present in roughly half of all insect species, creates conditions where dengue virus cannot replicate inside mosquitoes, effectively breaking the transmission cycle when these modified insects bite humans.

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A Nature survey of more than 1,100 physicists reveals fundamental disagreements about quantum mechanics' relationship to reality, despite the theory's century-long track record as one of science's most successful frameworks. The survey, conducted to mark quantum mechanics' 100th anniversary, found 36% of researchers favor the Copenhagen interpretation while 17% prefer epistemic approaches that treat quantum states as information rather than physical reality. Another 15% support the many-worlds interpretation. Researchers split evenly on whether a boundary exists between quantum and classical worlds -- 45% said yes, 45% said no. When asked about the wavefunction's nature, 47% called it a mathematical tool while 36% considered it a representation of physical reality. Only 24% of respondents expressed confidence their chosen interpretation was correct, with others viewing their preference as merely adequate or useful in certain circumstances. The survey contacted over 15,000 researchers whose recent papers involved quantum mechanics, plus attendees of a centenary meeting on Heligoland island. Despite quantum mechanics enabling technologies from computer chips to medical imaging, physicists remain divided on the physical reality underlying the mathematics.

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