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Oct 19, 2023

Researchers test seafloor fiber optic cable as an earthquake early warning system

Posted by in category: electronics

One of the biggest challenges for earthquake early warning systems (EEW) is the lack of seismic stations located offshore of heavily populated coastlines, where some of the world’s most seismically active regions are located.

In a new study published in The Seismic Record, researchers show how unused telecommunications fiber can be transformed for offshore EEW.

Jiuxun Yin, a Caltech researcher now at SLB, and colleagues used 50 kilometers of a submarine telecom cable running between the United States and Chile, sampling at 8,960 channels along the cable for four days. The technique, called Distributed Acoustic Sensing or DAS, uses the tiny internal flaws in a long optical fiber as thousands of seismic sensors.

Oct 19, 2023

Vocal functional flexibility in the grunts of young chimpanzees

Posted by in categories: biotech/medical, evolution, genetics

Half a century after its foundation, the neutral theory of molecular evolution continues to attract controversy. The debate has been hampered by the coexistence of different interpretations of the core proposition of the neutral theory, the ‘neutral mutation–random drift’ hypothesis. In this review, we trace the origins of these ambiguities and suggest potential solutions. We highlight the difference between the original, the revised and the nearly neutral hypothesis, and re-emphasise that none of them equates to the null hypothesis of strict neutrality. We distinguish the neutral hypothesis of protein evolution, the main focus of the ongoing debate, from the neutral hypotheses of genomic and functional DNA evolution, which for many species are generally accepted. We advocate a further distinction between a narrow and an extended neutral hypothesis (of which the latter posits that random non-conservative amino acid substitutions can cause non-ecological phenotypic divergence), and we discuss the implications for evolutionary biology beyond the domain of molecular evolution. We furthermore point out that the debate has widened from its initial focus on point mutations, and also concerns the fitness effects of large-scale mutations, which can alter the dosage of genes and regulatory sequences. We evaluate the validity of neutralist and selectionist arguments and find that the tested predictions, apart from being sensitive to violation of underlying assumptions, are often derived from the null hypothesis of strict neutrality, or equally consistent with the opposing selectionist hypothesis, except when assuming molecular panselectionism. Our review aims to facilitate a constructive neutralist–selectionist debate, and thereby to contribute to answering a key question of evolutionary biology: what proportions of amino acid and nucleotide substitutions and polymorphisms are adaptive?

Oct 19, 2023

Moderating the neutralist–selectionist debate: exactly which propositions are we debating, and which arguments are valid?

Posted by in categories: biotech/medical, evolution, genetics

Half a century after its foundation, the neutral theory of molecular evolution continues to attract controversy. The debate has been hampered by the coexistence of different interpretations of the core proposition of the neutral theory, the ‘neutral mutation–random drift’ hypothesis. In this review, we trace the origins of these ambiguities and suggest potential solutions. We highlight the difference between the original, the revised and the nearly neutral hypothesis, and re-emphasise that none of them equates to the null hypothesis of strict neutrality. We distinguish the neutral hypothesis of protein evolution, the main focus of the ongoing debate, from the neutral hypotheses of genomic and functional DNA evolution, which for many species are generally accepted. We advocate a further distinction between a narrow and an extended neutral hypothesis (of which the latter posits that random non-conservative amino acid substitutions can cause non-ecological phenotypic divergence), and we discuss the implications for evolutionary biology beyond the domain of molecular evolution. We furthermore point out that the debate has widened from its initial focus on point mutations, and also concerns the fitness effects of large-scale mutations, which can alter the dosage of genes and regulatory sequences. We evaluate the validity of neutralist and selectionist arguments and find that the tested predictions, apart from being sensitive to violation of underlying assumptions, are often derived from the null hypothesis of strict neutrality, or equally consistent with the opposing selectionist hypothesis, except when assuming molecular panselectionism. Our review aims to facilitate a constructive neutralist–selectionist debate, and thereby to contribute to answering a key question of evolutionary biology: what proportions of amino acid and nucleotide substitutions and polymorphisms are adaptive?

Oct 19, 2023

Fast radio bursts trigger aftershocks resembling earthquakes, but not solar flares

Posted by in categories: energy, space

ABSTRACT. The production mechanism of repeating fast radio bursts (FRBs) is still a mystery, and correlations between burst occurrence times and energies may provide important clues to elucidate it. While time correlation studies of FRBs have been mainly performed using wait time distributions, here we report the results of a correlation function analysis of repeating FRBs in the 2D space of time and energy. We analyse nearly 7,000 bursts reported in the literature for the three most active sources of FRB 20121102A, 20201124A, and 20220912A, and find the following characteristics that are universal in the three sources. A clear power-law signal of the correlation function is seen, extending to the typical burst duration (∼ 10 msec) towards shorter time intervals (Δt). The correlation function indicates that every single burst has about a 10–60 per cent chance of producing an aftershock at a rate decaying by a power law as ∝ (Δt)−p with p = 1.5–2.5, like the Omori–Utsu law of earthquakes. The correlated aftershock rate is stable regardless of source activity changes, and there is no correlation between emitted energy and Δt. We demonstrate that all these properties are quantitatively common to earthquakes, but different from solar flares in many aspects, by applying the same analysis method for the data on these phenomena. These results suggest that repeater FRBs are a phenomenon in which energy stored in rigid neutron star crusts is released by seismic activity. This may provide a new opportunity for future studies to explore the physical properties of the neutron star crust.

Oct 19, 2023

A highly integrated bionic hand with neural control and feedback for use in daily life

Posted by in categories: cyborgs, neuroscience, transhumanism

A neuromusculoskeletal hand prosthesis grants long-term stable neural control, sensory feedback, and skeletal attachment.

Oct 19, 2023

A new view of all objects in the universe

Posted by in categories: cosmology, particle physics

The most comprehensive view of the history of the universe ever created has been produced by researchers at The Australian National University (ANU). The study also offers new ideas about how our universe may have started.

Lead author Honorary Associate Professor Charley Lineweaver from ANU said he set out wanting to understand where all the objects in the universe came from.

“When the universe began 13.8 billion years ago in a hot big bang, there were no objects like protons, atoms, people, planets, stars or galaxies. Now the universe is full of such objects,” he said.

Oct 19, 2023

Scientists propose super-bright light sources powered by quasiparticles

Posted by in categories: cosmology, engineering, particle physics

An international team of scientists is rethinking the basic principles of radiation physics with the aim of creating super-bright light sources. In a new study published in Nature Photonics, researchers from the Instituto Superior Técnico (IST) in Portugal, the University of Rochester, the University of California, Los Angeles, and Laboratoire d’Optique Appliquée in France proposed ways to use quasiparticles to create light sources as powerful as the most advanced ones in existence today, but much smaller.

Quasiparticles are formed by many moving in sync. They can travel at any speed—even faster than light—and withstand intense forces, like those near a black hole.

“The most fascinating aspect of quasiparticles is their ability to move in ways that would be disallowed by the laws of physics governing individual particles,” says John Palastro, a senior scientist at the Laboratory for Laser Energetics, an assistant professor in the Department of Mechanical Engineering, and an associate professor at the Institute of Optics.

Oct 19, 2023

In an ancient hot spring haunt of Inca rulers, scientists discover a new freshwater shrimp-like species

Posted by in category: habitats

In an ancient hot spring haunt of Incan rulers, researchers discovered a new species of tiny, shrimp-like scavengers known as amphipods thriving at record temperatures that can cook other crustaceans to death.

Although called freshwater shrimps, amphipods are not true shrimps. Typically, they dwell in cool aquatic and semi-aquatic habitats. So Japanese and Peruvian researchers were stunned when unidentified Hyalella showed up during a hot spring biota survey of Baños del Inca (Baths of the Inca) near the ancient Inca city of Cajamarca.

“Though the amphipod is a taxon with a great diversity of habitats, the discovery of a from a previously unexpected high-temperature environment is most surprising,” said study corresponding author Ko Tomikawa, professor at Hiroshima University’s (HU) Graduate School of Humanities and Social Sciences.

Oct 19, 2023

How do spacecraft avoid asteroid collision?

Posted by in categories: asteroid/comet impacts, existential risks

How do spacecraft avoid asteroid collision?

Oct 19, 2023

Brain fungal infection produces Alzheimer’s disease-like changes

Posted by in categories: biotech/medical, neuroscience

Previous research has implicated fungi in chronic neurodegenerative conditions such as Alzheimer’s disease, but there is limited understanding of how these common microbes could be involved in the development of these conditions.

Working with animal models, researchers at Baylor College of Medicine and collaborating institutions discovered how the fungus Candida albicans enters the brain, activates two separate mechanisms in brain cells that promote its clearance, and, important for the understanding of Alzheimer’s disease development, generates amyloid beta (Ab)-like peptides, toxic protein fragments from the amyloid precursor protein that are considered to be at the center of the development of Alzheimer’s disease. The study appears in the journal Cell Reports.

“Our lab has years of experience studying fungi, so we embarked on the study of the connection between C. albicans and Alzheimer’s disease in animal models,” said corresponding author Dr. David Corry, Fulbright Endowed Chair in Pathology and professor of pathology and immunology and medicine at Baylor. He also is a member of Baylor’s Dan L Duncan Comprehensive Cancer Center. “In 2019, we reported that C. albicans does get into the brain where it produces changes that are very similar to what is seen in Alzheimer’s disease. The current study extends that work to understand the molecular mechanisms.”