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Comment by Dr. Krishna Kumari Challa on April 27, 2023 at 8:32am

Astronomers solve the 60-year mystery of quasars, the most powerful objects in the universe

Scientists have unlocked one of the biggest mysteries of quasars—the brightest, most powerful objects in the universe—by discovering that they are ignited by galaxies colliding.

First discovered 60 years ago, quasars can shine as brightly as a trillion stars packed into a volume the size of our solar system. In the decades since they were first observed, what could trigger such powerful activity has remained a mystery. New work by scientists has now revealed that it is a consequence of galaxies crashing together.

The collisions were discovered when researchers, using deep imaging observations from the Isaac Newton Telescope in La Palma, observed the presence of distorted structures in the outer regions of the galaxies that are home to quasars.

Most galaxies have supermassive black holes at their centers. They also contain substantial amounts of gas—but most of the time this gas is orbiting at large distances from the galaxy centers, out of reach of the black holes. Collisions between galaxies drive the gas towards the black hole at the galaxy center; just before the gas is consumed by the black hole, it releases extraordinary amounts of energy in the form of radiation, resulting in the characteristic quasar brilliance.

The ignition of a quasar can have dramatic consequences for entire galaxies—it can drive the rest of the gas out of the galaxy, which prevents it from forming new stars for billions of years into the future.

This is the first time that a sample of quasars of this size has been imaged with this level of sensitivity. By comparing observations of 48 quasars and their host galaxies with images of over 100 non-quasar galaxies, researchers concluded that galaxies hosting quasars are approximately three times as likely to be interacting or colliding with other galaxies.

J C S Pierce et al, Galaxy interactions are the dominant trigger for local type 2 quasars, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad455

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 12:08pm

Earpiece that speeds up recovery after a stroke

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 11:40am

 How NASA is planning to protect Earth from asteroids and comets

NASA just released a new planetary defense strategy and action plan, describing its efforts to find and identify potentially hazardous objects to provide an advanced warning, and then even push them off an impact trajectory.

This 10-year strategy looks to advance efforts to protect the Earth from a devastating encounter with a Near Earth asteroid or comet.

The 46-page "NASA Planetary Defense Strategy and Action Plan" (pdf document) was released on April 18, 2023 and follows another document that was put out on April 3 by the White House Office of Science and Technology Policy, "National Preparedness Strategy and Action Plan for Near-Earth Object Hazards and Planetary Defense" (pdf document).

Each of the reports focuses on enhancing the detection, characterization and responses to impact threats as well as improving international cooperation for coordinating strategies among government agencies.

NASA wants to focus on six key areas for planetary defense over the next decade:

• Improving NEO survey, detection, and characterization efforts to work toward a completed catalog of all NEOs that might pose an impact hazard to Earth
• Developing and demonstrating NEO mitigation technologies similar to the agency's Double Asteroid Redirection Test (DART) mission, the world's first planetary defense test mission, which successfully demonstrated one method of asteroid deflection using a kinetic impactor spacecraft
• Fostering international collaboration related to NEO surveying and mitigation to leverage international capabilities
• Strengthening interagency coordination between NASA and other U.S. government agencies to enhance and streamline U.S. government NEO preparedness and response planning
• Review the agency's internal planning to maximize the benefits obtained from limited resources
• Better integrate messaging regarding planetary defense work with the agency's strategic communications

Each of the strategy objectives are defined into short-term, medium-term, long-term, and ongoing timelines with the goal of meeting all objectives within the next 10 years.

https://www.nasa.gov/feature/nasa-releases-agency-strategy-for-plan...

https://www.universetoday.com/161058/heres-how-nasa-is-planning-to-...

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 10:53am

How to land on a planet safely using a computational model

Understanding the interaction between the rocket plume and the surface is important for the safety and success of space missions in terms of contamination and erosion, landing accuracy, planetary protection, and engineering design, as well as for scientific understanding and future exploration.

When a lander descends toward the moon—or a rocky planet, asteroid, or comet—the exhaust plume of the rocket interacts with the surface, causing erosion and kicking up regolith particles. The resulting blanket of dusty debris can create a dangerous brownout effect, limiting visibility and potentially damaging the spacecraft or nearby equipment.

Researchers developed a model to describe the interaction between a rocket plume and the surface of a planetary body in near-vacuum conditions. The results can be used to evaluate the safety and feasibility of a proposed landing site and to optimize the design of spacecraft and rocket engines for planetary landings.

The computational framework takes in information about the rocket, its engines, and the surface composition and topography, as well as the atmospheric conditions and gravitational forces at the landing site.

By considering the interaction of the gas with solid particles as a system of equations, the simulation estimates the shape and size of the plume, the temperature and pressure of the plume and surface, and the amount of material eroded or displaced. It does so in a way that is more computationally efficient than previous methods.

In the model, small regolith particles reached high altitudes and caused severe brownout effects during ascent and descent. In contrast, larger particles with increased bed height led to a more favorable brownout status.

The insights gained from this study of the effects of different parameters on plume-surface interaction can inform the development of more effective and efficient landing technologies.

The researchers plan to improve the capabilities of the framework to include more complex physics, such as chemical reactions and solid particle collisions. They think the model can be applied to other physics scenarios including needle-free drug delivery systems.

Omid Ejtehadi et al, Full continuum approach for simulating plume-surface interaction in planetary landings, Physics of Fluids (2023). DOI: 10.1063/5.0143398

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 9:21am

The ongoing research aligns with the mission  where chemists are trying to discover the chemical "languages" of micro-organisms. Microbes use chemicals to communicate with each other, and then they use other chemicals to cooperate with or compete with each other. The researchers are applying chemical tools like

mass spectrometry and nuclear magnetic resonance spectroscopy  to decipher which molecules trigger cooperative and competitive responses in microbes.

Ultimately, they hope to use this knowledge to devise new approaches to defeat pathogens and promote the microbiomes that help humans.

 Núria Ros-Rocher et al, Chemical factors induce aggregative multicellularity in a close unicellular relative of animals, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2216668120

Part 2

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 9:18am

Earliest animal likely used chemical signaling to evolve into multicellular organism

The earliest animal likely used chemical signaling to evolve from a single cell to a multicellular organism, according to a study by scientists. The findings provide new information about how one of the biggest transitions in the history of life on Earth likely occurred.

The general view is that animals evolved from a unicellular organism, and this research helps explain how that may have happened and how those cells chose whether to be together or on their own.

The study focused on one of the closest living relatives of animals, Capsaspora owczarzaki, which lives in snails. Capsaspora can form multicellular aggregates—cells that cluster together and adhere to each other—in a way that is similar to sponges or hydra.

To conduct their study, researchers systematically added and removed components of a liquid growth media to Capsaspora to determine which components regulated the cells adhering together. They discovered that calcium ions and lipids spurred multicellular aggregation. They also found that the process was reversible, and that when lipoproteins decreased, the cells separated.

The transition from being a single cell to a multicellular organism is a really big step. We now have a better understanding of how the ancestors of animals could have made that change using chemical cues.

Researchers are working on additional studies involving Capsaspora. The snail that Capsaspora resides in transmits a parasitic disease, and Capsaspora can kill the worm that causes the disease. If researchers can determine how the organism does that, there could be future medical applications.

Part 1

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 8:50am

For this paper, the researchers modified those particles by adding a chemical group that would react with a tag placed on the second component in the system, which they call the crosslinker. Those crosslinkers, made of either PEG or PEG-PLGA, bind to the targeting particles that have accumulated at a wound site and form clumps that mimic blood clots. 

The idea is that with both of these components circulating inside the bloodstream, if there is a wound site, the targeting component will start accumulating at the wound site and also bind the crosslinker. When both components are at high concentration, you get more cross-linking, and they begin forming that glue and helping the clotting process.

To test the system, the researchers used a mouse model of internal injury. They found that after being injected into the body, the two-component system was highly effective at stopping bleeding, and it worked about twice as well as the targeting particle on its own.

Another important advantage of the clots is that they don't degrade as fast as naturally occurring clots do. When patients lose a lot of blood, they are usually given saline intravenously to keep up their blood pressure, but this saline also dilutes the existing platelets and fibrinogen, leading to weaker clots and faster degradation. However, the artificial clots are not as susceptible to this kind of degradation, the researchers found.

The researchers also found that their nanoparticles did not induce any significant immune reaction in the mice compared to a glucose control. They now plan to test the system in a larger animal model.

Celestine Hong et al, Engineering a Two‐Component Hemostat for the Treatment of Internal Bleeding through Wound‐Targeted Crosslinking, Advanced Healthcare Materials (2023). DOI: 10.1002/adhm.202202756

Part 2

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 8:47am

Two-component system could offer a new way to halt internal bleeding

Blood loss from traumatic events such as car crashes contributes to more than 2.5 million deaths per year worldwide. This kind of blunt trauma can cause internal bleeding from organs such as the liver, which is difficult to detect and treat. In such cases, it's critical to stop the bleeding as soon as possible, until a patient can be transported to the hospital for further treatment. Finding ways to prevent internal bleeding could have an especially significant impact in the armed services, where delayed treatment for internal hemorrhage is one of the largest causes of preventable death.

Engineers have now designed a two-component system that can be injected into the body and help form blood clots at the sites of internal injury. These materials, which mimic the way that the body naturally forms clots, could offer a way to keep people with severe internal injuries alive until they can reach a hospital.

When internal injuries occur, platelets are attracted to the site and initiate the blood clotting cascade, which eventually forms a sticky plug of platelets and clotting proteins, including fibrinogen. However, if patients are losing a lot of blood, they don't have enough platelets or fibrinogen to form clots. The engineer team wanted to create an artificial system that could help save people's lives by replacing both of those clotting components.

In a mouse model of internal injury, the researchers showed that these components—a nanoparticle and a polymer—performed significantly better than hemostatic nanoparticles that were developed earlier.

What was especially remarkable about these results was the level of recovery from severe injury they saw in the animal studies.

Unlike previously developed hemostatic systems, the new technology mimics the actions of both platelets—the cells that initiate blood clotting—and fibrinogen, a protein that helps forms clots. The idea of using two components allows selective gelation of the hemostatic system as the concentration is enhanced in the wound, mimicking the end effect of the natural clotting cascade.

What researchers in this area have been doing in the past is trying to either recapture the therapeutic effects of platelets or recapture the function of fibrinogen. This new one tried to capture the way they interact with each other.

To achieve that, the researchers created a system with two types of materials: a nanoparticle that recruits platelets and a polymer that mimics fibrinogen.

Part 1

Comment by Dr. Krishna Kumari Challa on April 25, 2023 at 1:36pm

The network "remembered" previous signals for at least seven steps. Curiously, seven is often regarded as the average number of items humans can keep in working memory at one time.

When researchers used reinforcement learning, they saw dramatic improvements in the network's memory performance.

In tehir nanowire networks, they found the formation of synaptic pathways depends on how those synapses have been activated in the past. This is also the case for synapses in the brain, where neuroscientists call it "metaplasticity".

Synthetic intelligence

Human intelligence is still likely a long way from being replicated.

Nonetheless, this research on neuromorphic nanowire networks shows it is possible to implement features essential for intelligence – such as learning and memory – in non-biological, physical hardware.

Nanowire networks are different from the artificial neural networks used in AI. Still, they may lead to so-called "synthetic intelligence".

Perhaps a neuromorphic nanowire network could one day learn to have conversations that are more human-like than ChatGPT, and remember them.

https://www.science.org/doi/10.1126/sciadv.adg3289

https://theconversation.com/networks-of-silver-nanowires-seem-to-le...

Part 3

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Comment by Dr. Krishna Kumari Challa on April 25, 2023 at 1:34pm

New work uses this nanowire system to explore the question of human-like intelligence. Central to the investigation are two features indicative of high-order cognitive function: learning and memory.

This study demonstrates we can selectively strengthen (and weaken) synaptic pathways in nanowire networks. This is similar to "supervised learning" in the brain.

In this process, the output of synapses is compared to a desired result. Then the synapses are strengthened (if their output is close to the desired result) or pruned (if their output is not close to the desired result).

Researchers expanded on this result by showing they could increase the amount of strengthening by "rewarding" or "punishing" the network. This process is inspired by "reinforcement learning" in the brain.

Part 2

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