Researchers reveal how wildfire accelerates forest changes

Stanford researchers identified tree species that are shifting their ranges toward cooler, wetter sites – an expected response to the recent warming and drying.
Image credit: Intricate Explorer/Unsplash

As climate conditions change, tree species are shifting their ranges. Wildfire is accelerating this process, likely by reducing competition from established species – a finding that raises questions about how to manage land in an era of shifting ecosystems.

Refugees are on the move in forests across the western U.S. As climate conditions change, the ranges of tree species are shifting, especially toward cooler or wetter sites. A new Stanford analysis provides some of the first empirical evidence that wildfire is accelerating this process, likely by reducing competition from established species. The study, published Nov. 15 in Nature Communications, raises questions about how to manage land in an era of shifting ecosystems – a key issue as President Biden prepares to sign into law an infrastructure bill that allocates more than $5 billion for forest restoration and wildfire risk reduction.

“Complex, interdependent forces are shaping the future of our forests,” said study lead author Avery Hill, a graduate student in biology at Stanford’s School of Humanities & Sciences. “We leveraged an immense amount of ecological data in the hopes of contributing to a growing body of work aimed at managing these ecosystem transitions.”

Research explores origins of blood feeding in mosquitoes

An interdisciplinary team of Virginia Tech researchers is seeking to understand the physiological and biomechanical characteristics of blood feeding in mosquitoes and their evolutionary transition from sugar to blood feeding — knowledge that may help future work to stop disease transmission.

“Mosquitoes are the deadliest animals on the planet due to the pathogens they transmit to humans and other animals,” said Chloé Lahondère, an assistant professor of biochemistry in the College of Agriculture and Life Sciences and an affiliate faculty member of the Center for Emerging, Zoonotic, and Arthropod-borne Pathogens in the Fralin Life Sciences Institute.

“Female mosquitoes transmit pathogens while biting a host,” she continued. "Females can also feed on plants, so food sources include blood, nectar, and plant fluids, which differ widely in viscosity and temperature. One of the key objectives of our project is to understand the specific adaptations that allow certain species of female mosquitoes to feed on such a wide range of fluids.”

Lahondère and Clément Vinauger, also an assistant professor in biochemistry in the College of Agriculture and Life Sciences and an affiliate faculty of the Center for Emerging, Zoonotic, and Arthropod-borne Pathogens, will work with Jake Socha, the Samuel Herrick Professor in biomedical engineering and mechanics, and Mark Stremler, professor in biomedical engineering and mechanics in the College of Engineering, to analyze the biomechanical constraints and trade-offs between sugar and blood feeding in mosquitoes, thanks to a $1 million grant from the National Science Foundation.

Safe Thanksgiving playbook as new COVID surge expected

As the U.S. braces for a new surge of COVID-19 cases expected to start hitting around Thanksgiving, Northwestern Medicine experts offer a playbook to a safe holiday gathering.

Vaccines are paramount for a safe Thanksgiving in 2021, which will be less restricted than last year. But Christmas will be even better once children five and over are fully vaccinated, experts say.

“Vaccines are a game changer, but we can’t let the pendulum swing too far and pretend we are back to pre-COVID normalcy,” said Dr. Sadiya Khan, assistant professor of medicine in epidemiology at Northwestern University Feinberg School of Medicine.

Special caution has to be taken around older adults who are most vulnerable to having a severe outcome from COVID-19, if they have not yet had a booster or have underlying conditions including cancer, cardiovascular diseases, chronic kidney disease, diabetes, severe obesity or uncontrolled hypertension.

Khan, and Mercedes Carnethon, vice chair of preventive medicine at Northwestern, offer a roadmap for a safe celebration in two weeks and how that will change for Christmas.

Mercedes Carnethon

“This year celebrations can expand somewhat, but your vaccinated older adult is still at higher risk than your unvaccinated child. Children over five will not have completed the vaccination series by Nov. 25, so it’s risky if you are bringing semi-vaccinated children in front of older adults, some of whom are still at risk for severe illness and breakthrough infections.

“Older adults are still vulnerable during indoor family celebrations, even if they have received the booster. It’s worth a discussion about comfort levels of older adults and their risk status and whether they received a booster shot. Individuals who are immunocompromised still may not have a very robust response to a booster, so I would hate for someone to put too much reliance on a booster. Nothing is risk free here.

“Everyone at the event is safest if everyone has received a vaccine. If they haven’t, disinvite them from the meal part when masks have to be off.”

Climate change will destroy familiar environments, create new ones and undermine efforts to protect sea life

 A healthy coral reef in 2012 in the Northern Mariana Islands. A year later, the reef was dead. The reef is a symbol of how climate change is already transforming ocean environments.
Credit: Steven Mana‘oakamai Johnson

Climate change is altering familiar conditions of the world’s oceans and creating new environments that could undermine efforts to protect sea life in the world’s largest marine protected areas, new research from Oregon State University shows.

The changing conditions also have cultural and economic implications for the people whose traditions and livelihoods are dependent on ocean resources, said James Watson, an assistant professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences and the paper’s co-author.

“What we’re looking at here is the potential extinction of a whole environment,” said Watson, who specializes in marine social-ecological systems and understanding complex adaptive systems. “In some places, the environments we have today are not going to exist in the future. We won’t be able to go visit them or experience them. It is an environmental, cultural and economic loss we can’t replace.”

The researchers’ analysis of multiple climate scenarios showed:

• 60% to 87% of the ocean is expected to experience multiple biological and chemical changes, such as increases in water temperature, higher levels of acidity and changes in oxygen levels, by the year 2060.
• The rate of change is expected to be even higher, 76% to 97%, in very large marine protected areas such as Australia’s Great Barrier Reef Marine Park and the Galapagos Marine Reserve in Ecuador.
• Increases in pH, which measures ocean acidity, are expected as soon as 2030. Ocean acidification reduces the amount of carbonate in seawater, which is necessary for marine organisms, such as corals and mollusks like oysters, to develop their shells and skeletons.

Simulations provide clue to missing planets mystery

A protoplanetary disk as observed by ALMA (left), and a protoplanetary disk during planetary migration, as obtained from the ATERUI II simulation (right). The dashed line in the simulation represents the orbit of a planet, and the gray area indicates a region not covered by the computational domain of the simulation.

Cerdit: Kazuhiro Kanagawa, ALMA(ESO/NAOJ/NRAO) 

Forming planets are one possible explanation for the rings and gaps observed in disks of gas and dust around young stars. But this theory has trouble explaining why it is rare to find planets associated with rings. New supercomputer simulations show that after creating a ring, a planet can move away and leave the ring behind. Not only does this bolster the planet theory for ring formation, the simulations show that a migrating planet can produce a variety of patterns matching those actually observed in disks.

Young stars are encircled by protoplanetary disks of gas and dust. One of the world’s most powerful radio telescope arrays, ALMA (Atacama Large Millimeter/submillimeter Array), has observed a variety of patterns of denser and less dense rings and gaps in these protoplanetary disks. Gravitational effects from planets forming in the disk are one theory to explain these structures, but follow-up observations looking for planets near the rings have largely been unsuccessful.

Is New Finding an Asteroid or a Comet? It’s Both

Composite image of (248370) 2005 QN173 taken with Palomar Observatory’s Hale Telescope in California on July 12, 2021. The head, or nucleus, of the comet is in the upper left corner, with the tail stretching down and to the right, getting progressively fainter farther from the nucleus. Stars in the field of view appear as short dotted lines due to the apparent motion of Solar System objects against background stars and the process of adding together multiple images to increase the visibility of the tail. 
Credit: Henry H. Hsieh (PSI), Jana Pittichová (NASA/JPL-Caltech)

The newest known example of a rare type of object in the Solar System – a comet hidden among the main-belt asteroids – has been found and studied, according to a new paper by Planetary Science Institute Senior Scientist Henry Hsieh.

Discovered to be active on July 7, 2021 by the Asteroid Terrestrial-Impact Last Alert System (ATLAS) survey, asteroid (248370) 2005 QN137 is just the eighth main-belt asteroid, out of more than half a million known main-belt asteroids, confirmed to not only be active, but to have been active on more than one occasion. “This behavior strongly indicates that its activity is due to the sublimation of icy material,” said Hsieh, lead author of the paper “Physical Characterization of Main-Belt Comet (248370) 2005 QN173” that he presented at a press conference today at the 53rd annual meeting of the American Astronomical Society’s Division for Planetary Sciences. “As such, it is considered a so-called main-belt comet, and is one of just about 20 objects that have currently been confirmed or are suspected to be main-belt comets, including some that have only been observed to be active once so far.

“248370 can be thought of as both an asteroid and a comet, or more specifically, a main-belt asteroid that has just recently been recognized to also be a comet. It fits the physical definitions of a comet, in that it is likely icy and is ejecting dust into space, even though it also has the orbit of an asteroid,” Hsieh said. “This duality and blurring of the boundary between what were previously thought to be two completely separate types of objects – asteroids and comets – is a key part of what makes these objects so interesting.”

Artificial intelligence predicts eye movements

© pexels.com

Scientists develop a software that can be used in combination with MRI data for research and diagnosis

Viewing behavior provides a window into many central aspects of human cognition and health, and it is an important variable in many functional magnetic resonance imaging (fMRI) studies. Researchers from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig and the Kavli Institute for Systems Neuroscience in Trondheim have now developed software that uses artificial intelligence to directly predict eye position and eye movements from MRI images. The method opens up rapid and cost-effective research and diagnostic possibilities, for example, in neurological diseases that often manifest as changes in eye-movement patterns.

To record eye movements, research institutions typically use a so-called eye tracker - a sensor technology in which infrared light is projected onto the retina, reflected, and eventually measured. "Because an MRI has a very strong magnetic field, you need special MRI-compatible equipment, which is often not feasible for clinics and small laboratories", says study author Matthias Nau, who developed the new alternative together with Markus Frey and Christian Doeller. The high cost of these cameras and the experimental effort involved in their use have so far prevented the widespread use of eye tracking in MRI examinations. That could now change. The scientists from Leipzig and Trondheim developed the easy-to-use software "DeepMReye" and provide it for free.

Breaking down fungal biofilm defenses provides potential path to treating sticky infections

David Andes is a professor of medicine at the
University of Wisconsin School of Medicine and Public Health.

The microbes that make us sick often have ways to evade our attacks against them. Perhaps chief among these strategies is a sticky, armor-like goo, called the biofilm matrix, that encases clusters of disease-causing organisms.

This defense works, sometimes in tragic ways. For example, biofilms form readily and invisibly on medical devices like catheters and implants and are highly resistant to drugs that might otherwise treat them. The infections they cause cost tens of thousands of lives and billions of dollars a year in the U.S.

“There are no approved antimicrobials to treat biofilms. The only way to treat a biofilm is to physically remove it from the body,” says David Andes, a professor of medicine at the University of Wisconsin School of Medicine and Public Health.

In a new study designed to better understand and combat these structures, Andes and his collaborators identified some of the key proteins in biofilms of the fungus Candida albicans that control both how they resist antifungal drugs and how they become dispersed throughout the body.

While more work is necessary, the newly identified proteins provide potential drug targets to impair a pathogen’s antimicrobial defenses. In fact, the study found that Candida that could not make some of these proteins were much more sensitive to the existing antifungal fluconazole.

However, interfering with some of these same proteins made the biofilms more likely to spread to the kidney in a rat model of infection. This is a shortcoming that further research will need to address.

Could liposomes be the unsung heroes of the pandemic?

UC Berkeley engineers attached SARS-CoV-2 “spike” proteins to the surface of liposomes, creating lab-made mimics of the deadly virus called “spike-liposomes,” which, when paired with a new DNA-patterning technique, could enable efficient testing of antibody therapies. This microscope image of their technique shows that mixing spike-liposomes (top right, tagged with green fluorescent protein) with ACE2 receptor (bottom red, tagged with red fluorescent protein), results in a composite of both proteins (left), indicating that their spike-liposomes bind to ACE2 receptor in the same way as SARS-CoV-2 virus.
Image by Molly Kozminsky

Liposomes may be the unsung heroes of the COVID-19 pandemic. Without the protection of these microscopic vesicles, the delicate strands of messenger RNA (mRNA) that lie at the heart of the Pfizer and Moderna COVID-19 vaccines would be quickly destroyed by enzymes in the body, making it nearly impossible for their genetic instructions to reach the insides of human cells.

But vaccine delivery isn’t the only way that these particles can be used in the battle against COVID-19. In a new study, a team of engineers at the University of California, Berkeley, attached SARS-CoV-2 “spike” proteins to the surface of liposomes, creating lab-made mimics of the deadly virus which the researchers call “spike-liposomes.” These spike-lipsomes can be used to test the efficacy of neutralizing antibodies that could potentially be used to treat COVID-19 patients.

The study also demonstrates how a new DNA-patterning technique, developed by the team last year, can help scientists rapidly characterize and conduct experiments on a variety of different types of liposomes, and their cousins, lipid nanoparticles.

Tiny chip provides a big boost in precision optics

A 1 mm by 1 mm integrated photonic chip developed by Jaime Cardenas, assistant professor of optics, and PhD student Meiting Song (lead author) will make interferometers—and therefore precision optics—even more powerful. Potential applications include more sensitive devices for measuring tiny flaws on mirrors, or dispersion of pollutants in the atmosphere, and ultimately, quantum applications. University of Rochester photo / J. Adam Fenster

By merging two or more sources of light, interferometers create interference patterns that can provide remarkably detailed information about everything they illuminate, from a tiny flaw on a mirror, to the dispersion of pollutants in the atmosphere, to gravitational patterns in far reaches of the Universe.

“If you want to measure something with very high precision, you almost always use an optical interferometer, because light makes for a very precise ruler,” says Jaime Cardenas, assistant professor of optics at the University of Rochester.

Now, the Cardenas Lab has created a way to make these optical workhorses even more useful and sensitive. Meiting Song, a PhD student, has for the first time packaged an experimental way of amplifying interferometric signals—without a corresponding increase in extraneous, unwanted input, or “noise”—on a 1 mm by 1 mm integrated photonic chip. The breakthrough, described in Nature Communications, is based on a theory of weak value amplification with waveguides that was developed by Andrew Jordan, a professor of physics at Rochester, and students in his lab.