Study could help solve mystery of the disappearing twins

An image of the binary stars Alpha Centauri A (left) and Alpha Centauri B, taken by the Hubble Space Telescope.
Image Credit: NASA

When supermassive stars are born, they’re almost always paired with a twin, and the two stars normally orbit one another.

But astronomers at UCLA’s Galactic Center Group and the Keck Observatory have analyzed over a decade’s worth of data about 16 young supermassive stars orbiting the supermassive black hole at the center of the Milky Way galaxy. Their findings, published today in the Astrophysical Journal, reveal a startling conclusion: All of them are singletons.

But why? Are the stars, which are about 10 times larger than our sun, being formed alone in the hostile environment around the black hole? Have their “twins” been kicked out by the black hole? Or have pairs of stars merged to form single stars?

The findings support a scenario in which the central supermassive black hole drives nearby stellar binaries to merge or be disrupted, with one of the pair being ejected from the system.

Like ancient mariners, ancestors of Prochlorococcus microbes rode out to sea on exoskeleton particles

New research suggests the Prochlorococcus microbe’s ancient coastal ancestors colonized the ocean by rafting out on chitin particles.
Illustration Credit: Jose-Luis Olivares/MIT
(CC BY-NC-ND 3.0)

Throughout the ocean, billions upon billions of plant-like microbes make up an invisible floating forest. As they drift, the tiny organisms use sunlight to suck up carbon dioxide from the atmosphere. Collectively, these photosynthesizing plankton, or phytoplankton, absorb almost as much CO2 as the world’s terrestrial forests. A measurable fraction of their carbon-capturing muscle comes from Prochlorococcus — an emerald-tinged free-floater that is the most abundant phytoplankton in the oceans today.

But Prochlorococcus didn’t always inhabit open waters. Ancestors of the microbe likely stuck closer to the coasts, where nutrients were plentiful and organisms survived in communal microbial mats on the seafloor. How then did descendants of these coastal dwellers end up as the photosynthesizing powerhouses of the open oceans today?

MIT scientists believe that rafting was the key. In a new study they propose that ancestors of Prochlorococcus acquired an ability to latch onto chitin — the degraded particles of ancient exoskeletons. The microbes hitched a ride on passing flakes, using the particles as rafts to venture further out to sea. These chitin rafts may have also provided essential nutrients, fueling and sustaining the microbes along their journey.

A multiomics approach provides insights into flu severity

Photo Credit: Andrea Piacquadio

Have you ever wondered why some people might get sicker than others, even when they catch the same virus? It is not yet clear why this is. Viral factors (such as differences in the strain of a virus) play a role in this variability, but they cannot account for the wide range of responses in different individuals infected by the same virus. A number of host factors have also been considered, including pre-existing immunity, age, sex, weight, and the microbiome.

Another important factor is the molecular biology within your cells. DNA is shown as one long double-helical strand. So, you might expect that the cell would always read genetic information in order, starting at one end and going to the other. But this isn’t the case. DNA contains transposable elements, sometimes called “junk DNA,” which can change the regions of the genome that are being read at a given time.

The work published in Cell Genomics by an international team led by Dr. Guillaume Bourque, who studied the role of these transposable elements on the severity of illness after influenza A virus infection.

Singing humpback whales respond to wind noise, but not boats

UQ researchers recorded humpback whales off the Queensland coast for the study.
Photo Credit: Mike Doherty

A University of Queensland study has found humpback whales sing louder when the wind is noisy, but don’t have the same reaction to boat engines.

Research lead Dr Elisa Girola from UQ’s Faculty of Science said this quirk of whale evolution could have consequences for breeding and behavior.

“Humpback whales evolved over millions of years with noise from natural sources but noise from man-made vessels is foreign to their instincts,” Dr Girola said.

“It’s a surprising finding given engine noise has a similar frequency range to the wind.

“It’s possible the whales are picking out other differences such as wind noise being broadband and the same over large areas, while vessel noise is generated by a single-point source with specific peaks in frequency.

“We don’t know yet if this lack of response to boat noise is making whales communicate less effectively or making breeding practices more difficult.

Testing a theory of supermassive black holes with 100 newly described 'blazars'

For some supermassive black holes, matter outside the event horizon is propelled at high speed in a jet that can be detected across the universe. When the jet is pointed in the direction of the Earth, it is typically called a blazar. Penn State researchers have characterized more than a hundred relatively dim blazars and used them to test a contentious theory of blazar emissions.
Illustration Credit: NASA/JPL-Caltech/GSFC

More than a hundred blazars — distant and active galaxies with a central supermassive black hole that drives powerful jets — have been newly characterized by Penn State researchers from a catalog of previously unclassified high-energy cosmic emissions. The new blazars, which are dim relative to more typical blazars, have allowed the researchers to test a controversial theory of blazar emissions, informing our understanding of black hole growth and even theories of general relativity and high-energy particle physics.

A paper describing the blazars and the theory has been accepted for publication in the Astrophysical Journal, and the peer-reviewed accepted version appears online on the preprint server arXiv.

Supermassive black holes can be millions or billions of times the mass of our sun. In some cases, matter outside of the black hole’s event horizon is propelled in a jet, accelerating to nearly the speed of light and sending emissions across the universe. When the jet happens to be pointed directly at the Earth, the system is typically called a blazar.

NUS scientists develop a novel light-field sensor for 3D scene construction with unprecedented angular resolution

Prof Liu Xiaogang (right) and Dr Yi Luying from the NUS Department of Chemistry capturing a 3D image of a model using the light-field sensor.
Photo Credit: Courtesy of National University of Singapore

Color-encoding technique for light-field imaging has potential applications in fields such as autonomous driving, virtual reality and biological imaging

A research team from the National University of Singapore (NUS) Faculty of Science, led by Professor Liu Xiaogang from the Department of Chemistry, has developed a 3D imaging sensor that has an extremely high angular resolution, which is the capacity of an optical instrument to distinguish points of an object separated by a small angular distance, of 0.0018o. This innovative sensor operates on a unique angle-to-color conversion principle, allowing it to detect 3D light fields across the X-ray to visible light spectrum.  

A light field encompasses the combined intensity and direction of light rays, which the human eyes can process to precisely detect the spatial relationship between objects. Traditional light sensing technologies, however, are less effective. Most cameras, for instance, can only produce two-dimensional images, which is adequate for regular photography but insufficient for more advanced applications, including virtual reality, self-driving cars, and biological imaging. These applications require precise 3D scene construction of a particular space.

Ancestral mitoviruses discovered in mycorrhizal fungi

Arbuscular mycorrhizal (AM) fungi in the Glomeromycotina colonize plant roots (left, micrograph) and deliver water and nutrients from soil (right).
Image Credit: Tatsuhiro Ezawa

A new group of mitochondrial viruses confined to the arbuscular mycorrhizal fungi Glomeromycotina may represent an ancestral lineage of mitoviruses.

Mitochondria are organelles in the cells of almost all eukaryotes — organisms with cells that have a nucleus. They were originally free-living bacteria capable of generating energy in the presence of oxygen; then engulfed by an ancestral eukaryotic cell where they became mitochondria, the site of cellular respiration and many important metabolic processes. In humans, dysfunctions of mitochondria are associated with aging and many diseases.

Bacteriophages are viruses that infect bacteria. As former bacteria, there are also viruses that infect mitochondria, known as mitoviruses, which evolved from bacteriophages. While mitoviruses have been found in fungi, plants, and invertebrates, they are not well studied.

Associate Professor Tatsuhiro Ezawa at Hokkaido University, Professor Luisa Lanfranco at University of Torino, and Dr. Massimo Turina at National Research Council of Italy (CNR) Torino led an international team to discover a new group of mitoviruses, called large duamitoviruses. Their findings were published in the journal mBio.

Celestial monsters at the origin of globular clusters

Scientists have found strong evidence that supermassive stars existed within globular clusters when they formed 13 billion years ago. Here, an image of the globular cluster M13, 22 000 light years from Earth, consisting of a million stars squeezed into a space 150 light years across.
Image Credits: HST STScI NASA ESA

A team from the universities of Geneva, Paris and Barcelona has found strong evidence that supermassive stars can explain the anomalies observed in large clusters of stars.

Globular clusters are the most massive and oldest star clusters in the Universe. They can contain up to 1 million of them. The chemical composition of these stars, born at the same time, shows anomalies that are not found in any other population of stars. Explaining this specificity is one of the great challenges of astronomy. After having imagined that supermassive stars could be at the origin, a team from the Universities of Geneva and Barcelona, and the Institut d’Astrophysique de Paris (CNRS and Sorbonne University) believes it has discovered the first chemical trace attesting to their presence in globular proto-clusters, born about 440 million years after the Big Bang. These results, obtained thanks to observations by the James-Webb space telescope, are to be found in Astronomy and Astrophysics.

Globular clusters are very dense groupings of stars distributed in a sphere, with a radius varying from a dozen to a hundred light years. They can contain up to 1 million stars and are found in all types of galaxies. Ours is home to about 180 of them. One of their great mysteries is the composition of their stars: why is it so varied? For instance, the proportion of oxygen, nitrogen, sodium and aluminum varies from one star to another. However, they were all born at the same time, within the same cloud of gas. Astrophysicists speak of "abundance anomalies".

Cancer may lurk in ‘normal looking’ skin

Researchers say reducing skin mutations in 'normal looking' skin could reduce the risk of skin cancers.
Photo Credit: Anna Nekrashevich

A University of Queensland study has found skin with few visible freckles or blemishes may still carry sun-damaged DNA mutations that can trigger cancer.

Researchers from UQ’s Frazer Institute Dermatology Research Centre investigated the relationship between the number of mutations found in ‘normal looking’ skin and the number of a person’s past skin cancers.

Lead author and PhD candidate Ms. Ho Yi Wong said the findings show Australians can still have a high number of mutations in skin they think looks normal.

“We took skin samples from the forearms of 37 skin cancer patients which were frequently sun exposed,” Ms. Wong said.

“They had an average of 4-5 times more mutations in normal looking skin compared to similar studies overseas.

Jellybeans – a sweet solution for overcrowded circuitry in quantum computer chips

Engineers show that a jellybean-shaped quantum dot creates more breathing space in a microchip packed with qubits.

The silicon microchips of future quantum computers will be packed with millions, if not billions of qubits – the basic units of quantum information – to solve the greatest problems facing humanity. And with millions of qubits needing millions of wires in the microchip circuitry, it was always going to get cramped in there.

But now engineers at UNSW Sydney have made an important step towards solving a long-standing problem about giving their qubits more breathing space -- and it all revolves around jellybeans.

Not the kind we rely on for a sugar hit to get us past the 3pm slump. But jellybean quantum dots –elongated areas between qubit pairs that create more space for wiring without interrupting the way the paired qubits interact with each other.

As lead author Associate Professor Arne Laucht explains, the jellybean quantum dot is not a new concept in quantum computing, and has been discussed as a solution to some of the many pathways towards building the world’s first working quantum computer.