Young stellar jets are a common by-product of star formation and are thought to be caused by the interplay between the magnetic fields of rotating young stars and the disks of gas surrounding them. These interactions eject twin torrents of ionized gas in opposite directions, such as those pictured in two images captured by astronomers using the Gemini South telescope on Cerro Pachón on the edge of the Chilean Andes. Gemini South is one half of the international Gemini Observatory, a Program of NSF’s NOIRLab, that comprises twin 8.1-meter optical/infrared telescopes on two of the best observing sites on the planet. Its counterpart, Gemini North, is located near the summit of Maunakea in Hawai’i.

The jet in the first image, named MHO 2147, is roughly 10,000 light-years from Earth, and lies in the galactic plane of the Milky Way, close to the boundary between the constellations Sagittarius and Ophiuchus. MHO 2147 snakes across a starry backdrop in the image — an appropriately serpentine appearance for an object close to Ophiuchus. Like many of the 88 modern astronomical constellations, Ophiuchus has mythological roots — in ancient Greece it represented a variety of gods and heroes grappling with a serpent. MHO 1502, the jet pictured in the second image, is located in the constellation of Vela, approximately 2000 light-years away.

Most stellar jets are straight but some can be wandering or knotted. The shape of the uneven jets is thought to be related to a characteristic of the object or objects that created them. In the case of the two bipolar jets MHO 2147 and MHO 1502, the stars which created them are obscured from view.

In the case of MHO 2147, this young central star, which has the catchy identifier IRAS 17527-2439, is embedded in an infrared dark cloud — a cold, dense region of gas that is opaque at the infrared wavelengths represented in this image [1]. The sinuous shape of MHO 2147 is caused because the direction of the jet has changed over time, tracing out a gentle curve on either side of the central star. These almost unbroken curves suggest that MHO 2147 has been sculpted by continuous emission from its central source. Astronomers found that the changing direction (precession) of the jet may be due to the gravitational influence of nearby stars acting on the central star. Their observations suggest that IRAS 17527-2439 could belong to a triple star system separated by more than 300 billion kilometers (almost 200 billion miles).

MHO 1502, on the other hand, is embedded in a totally different environment — an area of star formation known as an HII region. The bipolar jet is composed of a chain of knots, suggesting that its source, thought to be two stars, has been intermittently emitting material.

These detailed images were captured by the Gemini South Adaptive Optics Imager (GSAOI), an instrument on the 8.1-meter-diameter Gemini South telescope. Gemini South is perched on the summit of Cerro Pachón, where dry air and negligible cloud cover provide one of the best observing sites on the planet. Even atop Cerro Pachón, however, atmospheric turbulence causes the stars to blur and twinkle.

GSAOI works with GeMs, the Gemini Multi-Conjugate Adaptive Optics System, to cancel out this blurring effect using a technique called adaptive optics. By monitoring the twinkling of natural and artificial guide stars up to 800 times a second, GeMs can determine how atmospheric turbulence is distorting Gemini South’s observations [2]. A computer uses this information to minutely adjust the shape of deformable mirrors, canceling out the distortions caused by turbulence. In this case, the sharp adaptive optics images have made it possible to recognize more details in each knot of the young stellar jets than in previous studies.

Notes

[1] Astronomical objects can appear very different at different wavelengths. For example, the dust surrounding newborn stars blocks visible light but is transparent at infrared wavelengths. Something similar also happens here on Earth — doctors can see right through you with an X-ray machine even though human bodies are not transparent at visible wavelengths. Astronomers therefore study the Universe across the electromagnetic spectrum to learn as much as possible about the Universe.

[2] Adaptive optics systems on telescopes often make use of “natural guide stars” which are bright stars that lie close to the target of an astronomical observation. Their brightness makes it easy to measure how atmospheric turbulence is distorting their appearance. Gemini South also uses artificial guide stars produced by shining powerful lasers into the upper atmosphere.

The new analysis provides an alternative to the hypothesis that the movement of tectonic plates is related to convection currents in the Earth’s mantle. Convection involves buoyant rise of heated fluids, which Hofmeister and her colleagues argue does not apply to solid rocks. They argue that force, not heat, moves large objects. The new research is published in a special paper of the Geological Society of America, as part of a forthcoming collection assembled in honor of geologist Warren B. Hamilton.

Earth’s internal workings are popularly modeled as dissipating heat generated by internal radioactivity and from leftover energy created during collisions when our planet formed. But even mantle convection proponents recognize that that amount of internal heat-energy is insufficient to drive large-scale tectonics. And there are other problems with using convection to explain observed plate motions.

Instead, Earth’s plates might be shifting because the sun exerts such a strong gravitational pull on the moon that it has caused the moon’s orbit around Earth to become elongated.

Over time, the position of the barycenter — the center of mass between the orbiting bodies of the Earth and the moon — has moved closer to Earth’s surface and now oscillates 600 km per month relative to the geocenter, Hofmeister said. This sets up internal stresses, as the Earth continues to spin.

“Because the oscillating barycenter lies ~4600 km from the geocenter, Earth’s tangential orbital acceleration and solar pull are imbalanced except at the barycenter,” Hofmeister said. “The planet’s warm, thick and strong interior layers can withstand these stresses, but its thin, cold, brittle lithosphere responds by fracturing.”

Daily spin flattens the Earth from a perfect spherical shape, which contributes to this brittle failure of the lithosphere. These two independent stresses create the mosaic of plates observed in the outer shell, the authors suggest. The variety of plate motions comes from the changes in size and direction of the imbalanced gravitational forces with time.

But how to test this alternative? Hofmeister suggested: “One test would be a detailed examination of the tectonics of Pluto, which is too small and cold to convect, but has a giant moon and a surprisingly young surface.”

The study includes a comparison of rocky planets that shows that the presence and longevity of volcanism and tectonism depend on the particular combination of moon size, moon orbital orientation, proximity to the sun and rates of body spin and cooling.

Earth is the only rocky planet with all the factors needed for plate tectonics, Hofmeister noted.

“Our uniquely large moon and particular distance from the sun are essential,” she said.

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Materials provided by Washington University in St. Louis. Original written by Talia Ogliore. Note: Content may be edited for style and length.

The findings are published this week in Cell, one of the scientific journals of Cell Press. Alexandra Walls and David Veesler in the Department of Biochemistry at the University of Washington in Seattle led the project.

Characteristics of the Delta and Omicron coronavirus variants of concern include enhanced transmissibility and immune evasion even in non-immunologically naïve individuals, compared to the ancestral pandemic coronavirus.

These characteristics, and the waning of immunity from vaccines, have led to breakthrough infections in vaccinated individuals. For the most part, otherwise healthy people who are vaccinated against the SARS-CoV-2 usually do not have severe symptoms if they do end up contracting the virus.

The researchers wanted to understand what effect catching the virus after being vaccinated has on neutralizing antibodies, and to see how durable and broad these responses are. Their hope is that advancing such knowledge will help guide vaccination policies and pandemic mitigation strategies.

Through their project the researchers learned that the degree of antibody response depended on whether a person has had one, two, three, or four exposures to the spike protein through infection, vaccination, or a mixture of the two. The scientists also checked antibody responses in groups of individuals who had been vaccinated after having COVID-19, those who were previously vaccinated and experienced a breakthrough infection, those who were vaccinated only, and those who were boosted and therefore vaccinated three times.

Among their study subjects, those who had completed a three-vaccination protocol, and those who had been vaccinated after recovering from COVID-19, and those with a breakthrough infection after vaccination launched almost comparable neutralizing antibody responses, in terms of magnitude and breadth. Their serum binding and antibody neutralizing responses to the spike protein in the current pandemic coronavirus variants were much more potent and lasting than those generated by people who had received only two doses of COVID-19 vaccine or who had a previous infection not followed by vaccination.

This observation suggested that the increased number of exposures to SARS-CoV-2 antigens, either through infection and vaccination or triple vaccination, enhanced the quality of antibody responses.

The researchers also looked at how broad the elicited antibodies could be. They investigated neutralization of the divergent Omicron SARS-CoV-2 variant of concern, currently responsible for the majority of cases in the United States. Their findings showed that boosted individuals (or those that have a mixture of infection and double vaccination) have neutralizing antibodies at similar levels to subjects vaccinated twice against the original ancestral strain. This suggests a large amount of immune evasion, but that vaccine boosters can help close the neutralizing antibody gap caused by Omicron.

Looking outside of the SARS-CoV-2 family shows a similar pattern, where repeated and multiple exposures improves the otherwise weak neutralizing antibody response to SARS-CoV. Finally, the authors did not identify improvements in antibody binding to common cold causing coronavirus spike proteins like OC43 or HKU1. This suggests that repeated SARS-CoV-2 exposure does not improve spike reactivity to more divergent coronaviruses. These findings support the development of broader sarbecovirus or coronavirus vaccines to be prepared in the event of a future spillover event.

The study groups consisted of about 15 people, from the Hospitalized or Ambulatory Adults with Respiratory Viral Infections, or HAARVI, project at the UW in Seattle. HAARVI, led by UW Medicine infectious disease physician Helen Chu, looks at recovered COVID-19 patients to study immune responses over time, to understand the long-term consequences of the infection, and to compare immune responses from vaccines and natural infections.

Researchers from the Department of Medicine and the Department of Laboratory Medicine and Pathology at the UW School of Medicine, and from Humabs Biomed SA, a subsidiary of Vir Biotechnology, also helped conduct the study.

The findings help explain how the new variant can escape pre-existing antibodies present in the human body, either from vaccination or naturally from a recent COVID-19 infection.

“We know that viruses evolve over time and acquire mutations, so when we first heard of the new Omicron variant, we wanted to identify the mutations specific to this variant,” said Kamlendra Singh, a professor in the MU College of Veterinary Medicine, assistant director of the MU Molecular Interactions Core and Bond Life Sciences Center investigator.

Singh collaborated with Saathvik Kannan, a freshman at Hickman High School in Columbia, Missouri, and Austin Spratt, an undergraduate student at MU, and Sid Byrareddy of the University of Nebraska Medical Center, to analyze protein sequences of Omicron samples from around the world, including South Africa, Botswana and the United States. The team identified 46 highly prevalent mutations specific to Omicron, including several located in the region of the virus’ spike protein where antibodies bind to the virus in order to prevent infection.

“The purpose of antibodies is to recognize the virus and stop the binding, which prevents infection,” Singh said. “However, we found many of the mutations in the Omicron variant are located right where the antibodies are supposed to bind, so we are showing how the virus continues to evolve in a way that it can potentially escape or evade the existing antibodies, and therefore continue to infect so many people.”

As antiviral treatments for individuals infected with COVID-19 continue to be developed, Singh explained that having a better understanding of how the virus is evolving will help ensure future antiviral treatments will be targeted toward the specific parts of the virus to produce the most effective outcomes.

In a recent trip to his native India, Singh met with Manish Sisodia, the deputy chief minister of Delhi, to discuss the launch of CoroQuil-Zn, a supplement that can be taken while infected with COVID-19 to help reduce one’s viral load. The supplement, which Singh helped to develop, is now being used by patients in Tamil Nadu, a state in India. The manufacturer will soon seek FDA approval for its distribution in the United States.

“The first step toward solving a problem is getting a better understanding of the specific problem in the first place,” Singh said. “It feels good to be contributing to research that is helping out with the pandemic situation, which has obviously been affecting people all over the world.”

“Omicron SARS-CoV-2 variant: Unique features and their impact on pre-existing antibodies” was recently published in Journal of Autoimmunity. Funding for the study was provided by the Bond Life Sciences Center, the National Institute of Allergy and Infectious Diseases and the National Strategic Research Institute at the University of Nebraska. Siddappa Byrareddy of the University of Nebraska Medical Center, Hitendra Chand of Florida International University and Kalicharan Sharma of Delhi Pharmaceutical Sciences and Research University were co-authors on the study.

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The researchers investigated how water flows in the Nicola watershed affect early summer-run Chinook salmon. The team used an advanced time-series model to understand 22 years of variation in Chinook salmon productivity. After accounting for ocean survival and density dependence, they discovered that the flow during August, when Chinook are rearing as juveniles, was the most important predictor of productivity. Higher August flows during adult spawning and migration also likely boost productivity, while lower flows during this time are linked to decline.

The results could help to inform water management given watershed activities and climate change in the region. The findings are newly published in the journal Ecological Solutions and Evidence.

“We found that August flows during juvenile rearing had the greatest impact on Chinook productivity out of any factor; the effect was very large,” says the study’s lead author, Luke Warkentin, who carried out the project as part of his masters research in SFU’s Salmon Watersheds Lab, in collaboration with scientists from Fisheries and Oceans Canada. “If there isn’t enough water during the summer, Chinook populations tend to decline.” On average, cohorts that experienced 50 per cent below average flows in the August of spawning and rearing had 29 per cent lower productivity.

Changing flows and cumulative effects

Over the past 100 years, Nicola River flows in August have decreased by 26 per cent, on average, based on analyses of long-term flow data.

“These long-term changes are probably the cumulative effect of climate change, water withdrawals for agricultural and other uses, and land use such as forestry,” says SFU biological sciences professor Jonathan Moore, the paper’s co-author.

Managing flows for people and fish

Water flows in rivers are controlled by many different human activities, such as water withdrawals for agriculture, dam operations, and forestry, as well as climate variability. The seasonal patterns of water flow can impact the survival and productivity of fishes. Yet, it can be difficult to know how much water particular rivers need in order to sustain or recover fish and their fisheries. The findings from this study can help guide management of environmental flows in systems with multiple demands on water systems, such as the Nicola River, and elsewhere.

In 2021, this region of B.C. suffered catastrophic floods and a heat dome that broke records and caused substantial harm to people and property.

“This data is helping to inform ongoing watershed planning and on-the-ground action in the Nicola by the five Nicola Bands and the Province,” says Leona Antoine who helps lead the Nicola Watershed Governance Project, and is associated with the Scw’exmx Tribal Council, not involved in the study. “Science such as this, as well as traditional knowledge and other sources of expertise, are guiding real change on the ground to steward this watershed.”

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