Tag Archives: bridge

Ancient 185,000-Year-Old Bridge of Neutral Hydrogen Gas Links Two D-Star Galaxies

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An international team of astronomers, as part of the Widefield Askap L-Band Legacy All-Sky Survey (Wallaby), observed DDO 137 (Wallaby J123424+062511). Their findings uncovered a vast bridge of neutral hydrogen, measuring 185,000 light-years, connecting the two galaxies, along with various arms and clouds that link to a longer gas tail (1.6 million light-years) previously identified by the Arecibo telescope.

Radio (left) and light (right) images of NGC 4532/DDO 137. Image credits: ICRAR/D. Lang, Perimeter Institute.

“This discovery marks a significant advance in our understanding of galaxy interactions,” stated Professor Lister Starley Smith from the University of Western Australia Node at the International Centre for Radio Astronomy Research (ICRAR).

“Our simulations indicate that the tidal forces between these galaxies play a crucial role in the observed gas dynamics in close vicinity to the massive Virgo clusters of galaxies.”

“As the galaxies approached the hot gas clouds surrounding the Virgo clusters—temperatures 200 times that of the sun—we experienced what is termed RAM pressure, resulting in gas being stripped away from the galaxy.”

“This phenomenon is analogous to atmospheric burn-up when a satellite reenters Earth’s upper atmosphere, albeit extended over a billion years.”

“The electron density and the velocity at which galaxies descend into these hot gas clouds sufficiently clarify why they were drawn from the galaxy toward the bridge and surrounding regions.”

This observation formed part of the Wallaby Survey, a comprehensive project aimed at mapping the sky and examining the hydrogen gas distribution across galaxies using CSIRO’s Askap Radio telescope.

“Neutral hydrogen is vital for star formation, making this discovery pivotal in understanding how galaxies interact and evolve, particularly in densely packed environments,” remarked Professor Kenji Bekki of ICRAR.

“This system exhibits striking similarities to our Milky Way and Magellanic Clouds, offering a unique opportunity for a detailed examination of such interactions,” noted Professor Stavely-Smith.

“Grasping the dynamics of these gas bridges is crucial for understanding galaxy evolution over time, the redistribution of galactic gases, and the various conditions impacting star formation within galaxies.”

“This enhances our overall understanding of the universe’s largest structures and their lifecycle.

result will be published in Monthly Notices from the Royal Astronomical Society.

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L. Stavely-Smith et al. 2025. WallabyPilot Survey: Extensive interaction between NGC 4532 and DDO 137 and Virgo clusters. mnras 543(1): 526-539; doi: 10.1093/mnras/staf1443

Source: www.sci.news

This New Experiment Could Bridge the Gaps in Our Theories

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Humanity is now closer to developing an inclusive “all theories” framework to explain the physical universe. A new paper has been published in PRX Quantum.

Three scientists from the US have designed an experiment they believe can bridge the gap between quantum mechanics and Einstein’s general theory of relativity.

Quantum Mechanics elucidates the physics of the subatomic realm, while General Relativity addresses the large-scale universe, encompassing the physics of space, time, and gravity. Unfortunately, the two theories do not align.

“Both quantum theory and Einstein’s gravity theory have undergone rigorous testing and perform exceptionally well,” stated Dr. Igor Pikovsky, an assistant professor of physics at the Stevens Institute in New Jersey, as reported by BBC Science Focus.

“However, one of the greatest challenges in modern physics is to unify these two theories into a single coherent framework. So far, such a joint theory remains elusive.”

Pikovsky, along with Dr. Jacob Coby from the University of Illinois, Urbana-Champaign, and Dr. Johannes Borlegaard from Harvard University, has conceived an experiment to elucidate how these two theories can coexist—an achievement that has never been accomplished before.

The goal? To uncover how quantum effects respond to the curvature of space-time.

The curvature of space-time, as described by Einstein, posits that gravity results from the bending of space and time around massive objects (like planets), causing time to pass more slowly closer to these objects.

Scientists have engineered atomic clock systems interconnected within quantum networks, demonstrating how they are influenced by curved space-time.

Atomic clocks are capable of measuring time with remarkable precision. Through a phenomenon known as entanglement, these quantum states can be interconnected, and the superposition principle allows clocks to experience multiple timeframes simultaneously, due to the unique property of existing in various states at once.

By situating these clocks in diverse locations, the quantum network can identify minute variations in time movement caused by the gravitational distortion of space-time.

“If successful, such a test would represent the inaugural assessment of the ‘quantum theory of curved space-time,’ shedding light on how quantum systems behave within the framework of Einstein’s gravity,” Pikovsky remarked.

Scientists are racing to develop quantum networks to enable future quantum internets that can connect quantum computers globally – credit: via Sakkmesterke

This experiment marks a crucial initial step in testing how these theories might be unified, relying on existing technology.

Pikovsky expressed hope that the paper would kindle “interest and excitement about the numerous mysteries that nature still holds.”

He added:

“Our findings indicate that quantum technology can be harnessed to address some of these questions through real-world experiments for the first time.”

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About our experts

Dr. Igor Pikovsky is an assistant professor of physics at the Stevens Institute in New Jersey, USA. He earned his PhD in Quantum Mechanics from the University of Vienna in 2014. His current research focuses on quantum phenomena, quantum fundamentals, and quantum information science.

Source: www.sciencefocus.com

Efforts to Bridge the Gap Between Teens and Phone Experts Conclude in Debate

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Are teenagers at risk of harm from their smartphones? Experts disagree

Drazen Zigic/Getty Images

Efforts to achieve a scientific agreement concerning the potential risks associated with smartphones and social media among youth have sparked ongoing debates among researchers. This lack of consensus highlights the challenges policymakers face in relying on current evidence to regulate these technologies.

Valerio Capraro from Italy’s University of Milano Bicocca, alongside over 100 colleagues from various disciplines, has launched a “consensus statement” addressing the adverse effects of smartphone usage on teenagers. “Instead of prolonging the debate, we aimed to find common ground among different viewpoints,” Capraro explains.

The team evaluated 26 specific assertions concerning the impact of smartphone use on teens’ mental health. These included concerns that extensive mobile phone use may result in sleep deprivation and behavioral addiction, drawn from the book Anxious Generation by Jonathan Haidt. While this work has significantly shaped discussions surrounding smartphones at New York University, it has also faced substantial criticism. Haidt is a co-author of the statement.

Researchers individually rated their agreement with each assertion and evaluated the robustness of the supporting evidence. Notably, 99% concurred that adolescent mental health has worsened significantly in the US, with similar trends observed in other Western nations. Additionally, 98% acknowledged a strong correlation between heavy smartphone use and sleep disorders. Over 94% identified specific challenges faced by young girls, such as peer comparison, pressure to appear perfect, and exposure to online sexual harassment.

Despite high agreement on these points, experts noted that the evidence merely indicates correlation and not causation. Many believe that further rigorous research, including longitudinal studies tracking smartphone users over time, is necessary to establish causality. In total, over 90% affirmed that there are issues affecting young people, yet only 52% supported implementing policy measures like age restrictions or limitations in schools.

Nevertheless, researchers argue that this does not justify inaction from policymakers. “While obtaining high-quality causal evidence for effective policymaking may take years, decision-makers often need to act quickly in a rapidly evolving landscape with limited data,” they emphasize.

However, scholars not involved in the consensus statement are challenging its findings. It has also drawn backlash over its stance on social media. For instance, Pete Etchells from Bath Spa University in the UK highlighted that out of the 288 invited experts, only approximately 120 engaged in the process. He suggests that those inclined to believe in the negative impact of smartphones are more likely to participate, potentially skewing the results. “I want to clarify the biases present in the expert dataset,” he notes. “I don’t believe this is intentional.”

Etchells, who has also authored a book on the topic, questions the selection process for the invited experts. Sonia Livingstone from the London School of Economics criticizes the chosen researchers for the consensus. “The extensive list was meant to ensure balance, but it predominantly reflects one side of the debate. If science lacks balance, it loses its integrity,” she argues.

Capraro defended the diversity of the panel, stating that “countless individuals are researching these topics worldwide,” making it impractical to reach out to all of them.

Concerns regarding participation have also arisen from Livingstone’s critiques. “The problem lies in the biased nature of the questions posed. They don’t consider,” she points out, “[whether] social media can enhance mental health, friendships, or a sense of belonging?” Capraro maintains that the study aimed to present as many perspectives as possible on this “highly debated topic.”

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Source: www.newscientist.com

An ancient stone bridge dating back 5,600 years signals the early settlement of humans on the Spanish island of Mallorca

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Archaeologists say Genovesa Cave Discovered in Mallorca, the main Balearic island and the Mediterranean's sixth largest, the find suggests that humans settled in the western Mediterranean much earlier than previously thought.

5,600-year-old underwater stone bridge in Genovesa Cave, Mallorca, Spain. Image courtesy of R. Landreth.

Limited archaeological evidence makes it difficult to reconstruct early human colonization of the Balearic Islands in the western Mediterranean.

By studying the 7.7-metre (25-foot) submerged bridge, Professor Bogdan Onak of the University of South Florida and his colleagues were able to provide compelling evidence of prior human activity within Genovesa Cave.

“The presence of this underwater bridge and other artefacts indicates a high level of activity and suggests that early settlers were aware of the cave's water resources and strategically built infrastructure to navigate through them,” Prof Onak said.

Genovesa Cave, located near the coast of Mallorca, has had parts of its passage flooded by rising sea levels and has clear calcite deposits when sea levels were higher.

These layers, along with the light-colored bands on the submerged bridge, act as markers to precisely track historical sea-level changes and pinpoint the date of the bridge's construction.

Previous studies had suggested a human presence at the site as far back as 9,000 years ago, but inconsistencies in nearby carbon-dated bones, pottery and other evidence, as well as poor preservation, had left the findings in doubt.

Recent studies have used charcoal, ash and bones found on the island to create a timeline of human settlement dating back about 4,400 years ago.

This allows the timeline of human presence to coincide with important environmental events, such as the extinction of the goat antelope. Myotragus balearix.

By analysing the bridge's mineral overgrowths and the height of the bridge's colour bands, the authors found that the bridge was built around 6,000 years ago – more than 2,000 years older than previous estimates, narrowing the gap in the timelines between eastern and western Mediterranean settlements.

“The history of the bridge's construction appears to be closely linked to the rapid Holocene sea-level rise just before 6,000 years ago and the brief period of sea-level stillness that caused parts of the upper part of the cave to be flooded,” the researchers said.

“Our chronology shows that sea-level rise stopped and stabilized for several hundred years, between 5,964 and 5,359 years ago. During this time, so-called phreatic expansions of speleothems (POS) formed in the cave lake and the characteristic 'bathtub ring' formed on the bridge.”

“Construction of the bridge probably began early in this period, as it was needed to cross the 0.25 metre deep lake, but it must have been completed before 5,600 years ago, when the upper part of the bridge was submerged.”

“Evidence suggests that humans constructed a cobblestone path and a sturdy bridge leading to the cave's water pool, facilitating access to the only dry part of the cave, located in the Sala d'Entrada across the lake.”

“The exact reason these structures in Genovesa Cave were built remains unclear.”

“However, the dating constraints imposed by the depth of the bridge, and the similar depths at which the POS and colour marks are found, support the idea that early humans were present on the island by 5,600 years ago, potentially extending the date back to 6,000 years ago.”

a paper A paper describing the findings was published in the journal Neurology today. Communication Earth and the Environment.

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BP Onac others2024. An underwater bridge built at least 5,600 years ago marks early human arrival on the Spanish island of Mallorca. Community Global Environment 5, 457; doi: 10.1038/s43247-024-01584-4

Source: www.sci.news

‘Refining Bridge Editing: A Potential Improvement Over CRISPR for DNA Modification’

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Bridge editing physically links two DNA strands

Visual Science

A powerful DNA-editing mechanism discovered in bacteria has the potential to enable much larger genome modifications than are currently possible with CRISPR-based techniques, but it is not yet clear whether it would work in human cells.

Patrick Shue Researchers at the Ark Institute in California call their new genome editing system the “bridge editing” system because it physically links, or bridges, two strands of DNA. “Using this system, we can modify large parts of the genome,” says Su. Su's team has figured out how bacterial “parasitic” DNA sequences naturally replicate using this system and how it can be applied to genome editing.

“We're excited about the possibility of making much broader genome modifications that go far beyond what we can do today with CRISPR,” he says, “and we see this as an important step toward a broader vision for genome design.”

CRISPR gene editing has revolutionized biology since it was introduced in 2012. It is used for a variety of purposes, and the first CRISPR-based therapeutic was approved last year. However, the basic form of CRISPR, which uses the Cas9 protein, is gene disruption rather than gene editing.

A standard CRISPR Cas9 protein has two parts: one part binds to a guide RNA molecule and looks for DNA that matches a specific section of the guide RNA. Custom guide RNAs are easy to create, so CRISPR Cas9 can be “programmed” to look for any part of the genome.

The second part of CRISPR Cas9 is a cutter that cuts the DNA when Cas9 binds to the target site. Once the cell has repaired the damage, Cas9 cuts it again. This action continues until an error is made during repair, resulting in the intended mutation of the target site.

While being able to mutate specific sites is useful, biologists want to make more precise changes, so they are modifying CRISPR proteins to edit DNA directly rather than relying on cellular repair mechanisms. For example, base editors can change one DNA letter to another without cutting the DNA, while prime editors can convert an extra section of guide RNA into DNA and add it to the target site.

These improved versions of CRISPR have the potential to treat a wide range of diseases, with several clinical trials already underway, but to address some diseases, more sophisticated genome modifications are needed. Many teams around the world are working on ways to achieve this. Some have realized that the mechanism by which genetic parasites cut and paste from one part of the genome to another, called IS110 elements, has potential because, like CRISPR, it is RNA-guided, but Hsu's team is the first to fully understand how it works.

The bridge-editing system consists of a so-called recombinase protein that binds to a guide RNA, such as the CRISPR Cas9 protein. What's unique about this system is that the guide RNA specifies two DNA sequences to seek out, not just one, Hsu's team found.

One sequence specifies the target site in the genome to modify, similar to CRISPR, and the other specifies the DNA to change. Using this system, DNA sequences of virtually any length can be added, deleted, or inverted.

There are already ways to do this, but they typically require multiple steps and leave behind a piece of extra DNA called a scar. “Bridge editing leaves virtually no scar,” Hsu says. “It offers an unprecedented level of control in engineering the genome.”

This means that it could be used for more than just replacing faulty genes, he says: It could also be useful for completely remaking the genomes of plants and animals. “What we want to do is go from inserting individual genes to doing chromosome-scale genome engineering,” Su says.

“The findings reported are certainly exciting and the underlying biology is truly surprising.” Steven Tang Bridge editing is being done at Columbia University in New York, but so far it has only been demonstrated to work in bacterial cells or in test tubes. Tang says it remains to be seen whether and to what extent bridge editing will work in complex cells like humans. But even if bridge editing doesn't work in initial tests in human cells, it may be possible to modify the system to work over time.

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Source: www.newscientist.com