Now an international team of astronomers, co-led by Laura Sales, an astronomer at the University of California, Riverside, reports in Nature Astronomythat it has used sophisticated simulations to detect a few “quenched” UDGs in low-density environments in the universe. A quenched galaxy is one that does not form stars.

“What we have detected is at odds with theories of galaxy formation since quenched dwarfs are required to be in clusters or group environments in order to get their gas removed and stop forming stars,” said Sales, an associate professor of physics and astronomy. “But the quenched UDGs we detected are isolated. We were able to identify a few of these quenched UDGs in the field and trace their evolution backward in time to show they originated in backsplash orbits.”

Here, “in the field” refers to galaxies isolated in quieter environments and not in a group or cluster environment. Sales explained that a backsplash galaxy is an object that looks like an isolated galaxy today but in the past was a satellite of a more massive system — similar to a comet, which visits our sun periodically, but spends the bulk of its journey in isolation, far from most of the solar system.

“Isolated galaxies and satellite galaxies have different properties because the physics of their evolution is quite different,” she said. “These backsplash galaxies are intriguing because they share properties with the population of satellites in the system to which they once belonged, but today they are observed to be isolated from the system.”

Dwarf galaxies are small galaxies that contain anywhere from 100 million to a few billion stars. In contrast, the Milky Way has 200 billion to 400 billion stars. While all UDGs are dwarf galaxies, all dwarf galaxies are not UDGs. For example, at similar luminosity, dwarfs show a very large range of sizes, from compact to diffuse. UDGs are the tail end of most extended objects at a given luminosity. A UDG has the stellar content of a dwarf galaxy, 10-100 times smaller than the Milky Way. But its size is comparable to the Milky Way, giving it the extremely low surface brightness that makes it special.

Sales explained that the dark matter halo of a dwarf galaxy has a mass at least 10 times smaller than the Milky Way, and the size scales similarly. UDGs, however, break this rule and show a radial extension comparable to that of much larger galaxies.

“One of the popular theories to explain this was that UDGs are ‘failed Milky Ways,’ meaning they were destined to be galaxies like our own Milky Way but somehow failed to form stars,” said José A. Benavides, a graduate student at the Institute of Theoretical and Experimental Astronomy in Argentina and the first author of the research paper. “We now know that this scenario cannot explain all UDGs. So theoretical models are arising where more than one formation mechanism may be able to form these ultradiffuse objects.”

According to Sales, the value of the new work is twofold. First, the simulation used by the researchers, called TNG50, successfully predicted UDGs with characteristics similar to observed UDGs. Second, the researchers found a few rare quenched UDGs for which they have no formation mechanism.

“Using TNG50 as a ‘time machine’ to see how the UDGs got to where they are, we found these objects were satellites several billion years before but got expelled into a very elliptical orbit and look isolated today,” she said.

The researchers also report that according to their simulations, quenched UDGs can commonly make up 25% of an ultradiffuse population of galaxies. In observations, however, this percentage is much smaller.

“This means a lot of dwarf galaxies lurking in the dark may have remained undetected to our telescopes,” Sales said. “We hope our results will inspire new strategies for surveying the low-luminosity universe, which would allow for a complete census of this population of dwarf galaxies.”

The study is the first to resolve the myriad of environments — from isolated dwarfs to dwarfs in groups and clusters — necessary to detect UDGs, and with high-enough resolution to study their morphology and structure.

Next, the research team will continue its study of UDGs in TNG50 simulations to better understand why these galaxies are so extended compared to other dwarf galaxies with the same stellar content. The researchers will use the Keck Telescope in Hawaii, one of the most powerful telescopes in the world, to measure the dark matter content of UDGs in the Virgo cluster, the closest galaxy cluster to Earth.

“Future telescopes, such as the Large Synoptic Survey Telescope or the Roman Space Telescope, come online in the next five to 10 years with capabilities of detecting many more of these intriguing UDGs,” Sales said.

The study was partially funded by a National Science Foundation CAREER award and a NASA Astrophysics Theory Program grant to Sales.

Currently in the early stages of development, the actuator will become a key part of research contributing to the future of robotic, bioelectronic and biomedical science.

“Electrochemical devices that transform electrical energy to mechanical energy have potential use in numerous applications, ranging from soft robotics and micropumps to autofocus microlenses and bioelectronics,” said Mohammad Reza Abidian, associate professor of biomedical engineering in the UH Cullen College of Engineering. He’s the corresponding author of the article “Organic Semiconductor Nanotubes for Electrochemical Devices,” published in the journal Advanced Functional Materials, which details the discovery.

Significant movement (which scientists define as actuation and measure as deformation strain) and fast response time have been elusive goals, especially for electrochemical actuator devices that operate in liquid. This is because the drag force of a liquid restricts an actuator’s motion and limits the ion transportation and accumulation in electrode materials and structures. In Abidian’s lab, he and his team refined methods of working around those two stumbling blocks.

“Our organic semiconductor nanotube electrochemical device exhibits high actuation performance with fast ion transport and accumulation and tunable dynamics in liquid and gel-polymer electrolytes. This device demonstrates an excellent performance, including low power consumption/strain, a large deformation, fast response and excellent actuation stability,” Abidian said.

This outstanding performance, he explained, stems from the enormous effective surface area of the nanotubular structure. The larger area facilitates the ion transport and accumulation, which results in high electroactivity and durability.

“The low power consumption/strain values for this OSNT actuator, even when it operates in liquid electrolyte, mark a profound improvement over previously reported electrochemical actuators operating in liquid and air,” Abidian said. “We evaluated long-term stability. This organic semiconductor nanotube actuator exhibited superior long-term stability compared with previously reported conjugated polymer-based actuators operating in liquid electrolyte.”

Joining Abidian on the project were Mohammadjavad Eslamian, Fereshtehsadat Mirab, Vijay Krishna Raghunathan and Sheereen Majd, all from the Department of Biomedical Engineering at the UH Cullen College of Engineering.

The organic semiconductors used, called conjugated polymers, were discovered in the 1970s by three scientists — Alan J. Heeger, Alan MacDiarmid and Hideki Shirakawa — who won a Nobel prize in 2000 for the discovery and development of conjugated polymers.

For a new type of actuator to outshine the status quo, the end product must prove not only to be highly effective (in this case, in both liquid and gel polymer electrolyte), but also that it can last.

“To demonstrate potential applications, we designed and developed a micron-scale movable neural probe that is based on OSNT microactuators. This microprobe potentially can be implanted in the brain, where neural signal recordings that are adversely affected, by either damaged tissue or displacement of neurons, may be enhanced by adjusting the position of the movable microcantilevers,” said Abidian.

The next step is animal testing, which will be undertaken soon at Columbia University. Early results are expected by the end of 2021, with longer term tests to follow.

“Considering the achievements so far, we anticipate these new OSNT-based electrochemical devices will help advance the next generation of soft robotics, artificial muscles, bioelectronics and biomedical devices,” Abidian said.

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Materials provided by University of Houston. Original written by Sally Strong. Note: Content may be edited for style and length.

While many parrot owners clip their birds’ wings to reduce their flight abilities, free-flight involves training an intact parrot to come when called, follow basic commands, recognize natural dangers, and otherwise safely fly in open areas.

In a recently published paper in Diversity 2021, Constance Woodman, a doctoral graduate student of the Texas A&M College of Veterinary Medicine & Biomedical Sciences (CVMBS), and Donald Brightsmith, a CVMBS associate professor, shared their findings from a project with Chris Biro, a globally recognized free-flight trainer, that included documenting Biro’s training process step by step so that conservationists can apply his methods when releasing birds into the wild.

Biro, one of the most experienced free-flight trainers, has trained more than 400 students from more than 30 countries on how to free-fly their birds, but his process had previously only been captured via video.

“We have colleagues up and down the Americas raising and releasing birds, but their main objective is conservation and they don’t have the chance to write up a lot of the science,” Brightsmith said. “A&M’s role in this project is to make sure that this information gets put into a place and a format so the rest of the world can read it, criticize it, use it, and improve it. If information hasn’t made it into scientific literature, it’s not improving the future of the science of macaw and parrot conservation, it’s just helping one or two populations.”

Woodman, supported by a National Science Foundation fellowship, and Biro spent several years training three different flocks of multiple parrot species using Biro’s techniques, thoroughly documenting every step of the process.

These 37 birds, which collectively spent 500 months in free-flight, were hand-raised from chicks to build a strong bond with the trainer before being gradually taught new commands and introduced to increasingly complex environments to learn the skills necessary to safely fly in open, uncontrolled areas.

“As scientists, one of the most important things we can do for conservation is offer ready-to-use solutions for practitioners on the ground who are trying to save animals and ecosystems,” said Woodman, who now serves as program manager for the CVMBS’ Conservation Innovation Grant program. “By learning from communities that already work with the target species, in this case parrot owners and trainers, we can take their knowledge and transform it into a conservation tool.”

The birds learned to recognize, evade, and even intimidate predators; forage for food and recognize safe vs. unsafe options; fly in flocks; navigate and mentally map the environment; and avoid unsafe situations, like dogs and cars.

During the entire training process, Biro’s methods were proven successful by the fact that neither trainer lost a single bird to predators or had a bird leave the training area.

Taking Flight

As the next step in this process, the team will work to adapt the training in support of parrot conservation.

Texas A&M and Biro’s nonprofit, Bird Recovery International, will be among the first to test free-flight as a conservation tool through collaborative projects in Brazil and Honduras.

Traditionally, attempting to release hand-reared parrots has resulted in birds that show little fear of humans, which increases their chances of being trapped by poachers or killed by people.

By using a “kernel flock” — human-socialized birds trained in free-flight — to teach survival behaviors to other parrots, conservationists should be able to release wild birds without having to train them themselves.

“The idea of using a kernel flock is a way to cut the difference when human socialization is not desirable in your wild birds,” Woodman said.

After the kernel flock trains the non-socialized birds, the kernel flock could be recalled and moved to another location, leaving behind a well-established colony of wild parrots.

“This is a really, really important project,” Biro said. “For example, the Spix’s macaw is extinct in the wild and there are only about 150 or so left in captivity. One of the problems of putting the Spix’s macaw back into Brazil is that there are limited options for introducing birds into environments where no flock exists. This project produces a flock where there isn’t one.”

Woodman said there are many groups of animal keepers, fanciers and breeders with specialty knowledge, “but they may not be plugged into conservation communities.”

“The work we’ve done — spending years working with a group to learn how they do what they do and then translating that into something useful for scientists and practitioners — is critically important to moving conservation forward,” Woodman said.

For parrot owners who are interested in learning free-flight, Woodman recommends finding a local free-flight community to learn more.

“Free-flight is highly technical and it almost requires an apprenticeship-type learning system to do well, just like with falconry,” Woodman said. “To free-fly a parrot safely, you’ve got to be involved in the free-flight community, because there’s always a risk of losing an animal and that risk goes up without proper training.”

However, studying how brain networks interact with each other is complicated. Brain networks can be explored by delivering brief pulses of electrical current in one area of a patient’s brain while measuring voltage responses in other areas. In principle, one should be able to infer the structure of brain networks from these data. However, with real-world data, the problem is difficult because the recorded signals are complex, and a limited amount of measurements can be made.

To make the problem manageable, Mayo Clinic researchers developed a set of paradigms, or viewpoints, that simplify comparisons between effects of electrical stimulation on the brain. Because a mathematical technique to characterize how assemblies of inputs converge in human brain regions did not exist in the scientific literature, the Mayo team collaborated with an international expert in artificial intelligence (AI) algorithms to develop a new type of algorithm called “basis profile curve identification.”

In a study published in PLOS Computational Biology, a patient with a brain tumor underwent placement of an electrocorticographic electrode array to locate seizures and map brain function before a tumor was removed. Every electrode interaction resulted in hundreds to thousands of time points to be studied using the new algorithm.

“Our findings show that this new type of algorithm may help us understand which brain regions directly interact with one another, which in turn may help guide placement of electrodes for stimulating devices to treat network brain diseases,” says Kai Miller, M.D., Ph.D., a Mayo Clinic neurosurgeon and first author of the study. “As new technology emerges, this type of algorithm may help us to better treat patients with epilepsy, movement disorders like Parkinson’s disease, and psychiatric illnesses like obsessive compulsive disorder and depression.”

“Neurologic data to date is perhaps the most challenging and exciting data to model for AI researchers,” says Klaus-Robert Mueller, Ph.D., study co-author and member of the Google Research Brain Team. Dr. Mueller is co-director of the Berlin Institute for the Foundations of Learning and Data and director of the Machine Learning Group — both at Technical University of Berlin.

In the study, the authors provide a downloadable code package so others may explore the technique. “Sharing the developed code is a core part of our efforts to help reproducibility of research,” says Dora Hermes, Ph.D., a Mayo Clinic biomedical engineer and senior author.

This research was supported by National Institutes of Health’s National Center for Advancing Translational Science Clinical and Translational Science Award, National Institute of Mental Health Collaborative Research in Computational Neuroscience, and the Federal Ministry of Education and Research.

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Materials provided by Mayo Clinic. Original written by Susan Barber Lindquist. Note: Content may be edited for style and length.