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Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 12:37pm

With this information to hand, the simulations can be put to work to provide real insights into how neutron stars throw their tremendous tantrums.

"We're close to modeling the flame spread across the whole star from pole to pole.

https://iopscience.iop.org/article/10.3847/1538-4357/ace04e

Part 4

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Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 12:37pm

That sounds simple, but the physics of neutron stars is really complicated; simulating their behavior requires a lot of computing power.

In previous work, the researchers used the Summit supercomputer at Oak Ridge National Laboratory to simulate the thermonuclear flames in two dimensions. Now they've built on that work, and scaled their simulations up to a third dimension.

The model 3D neutron star had a temperature several million times hotter than the Sun, and a spin speed of 1,000 rotations per second, which is pretty close to the theoretical upper limit of neutron star spin speed. Then, they simulated the early evolution of the thermonuclear flame.

Although the flame in the 2D simulation spread slightly faster than the 3D version, the growth trends in both models were very similar. This agreement means that the 2D simulation remains a good tool for studying these hectic explosions, but there are still some things it can't do.

For example, turbulence behaves differently in two and three dimensions; but being able to use the 2D sim for the parts it can do will free up computing power for other things, like increasing the fidelity of the burning

Part 3

Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 12:36pm

Neutron stars are some of the densest objects in the Universe. They're what's left over after a massive star has lived its life, run out of fuel, and exploded in a supernova.

While the outer material blasts off into space, though, the core of the star collapses under gravity, forming a super dense ball around 20 kilometers (12 miles) across, packing as much mass into that tiny sphere as up to 2.3 Suns or so.

Matter that is squished so densely is expected to be a bit wacky, to put it mildly. But scientists can study their thermonuclear bursts to place constraints on their size, which in turn can help model their interiors.

We can't exactly go cozy up to a neutron star to look at them more closely, for a number of reasons (distance, danger, that sort of thing), but we can collect all the information we can about neutron star X-ray bursts, and try to put together a simulation whose results match the observational data.

Part 2

Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 12:35pm

Scientists Ignited a Thermonuclear Explosion Inside a Supercomputer

Computer simulations are giving us new insight into the riotous behavior of cannibal neutron stars.

When a neutron star slurps up material from a close binary companion, the unstable thermonuclear burning of that accumulated material can produce a wild explosion that sends X-radiation bursting across the Universe.

How exactly these powerful eruptions evolve and spread across the surface of a neutron star is something of a mystery. But by trying to replicate the observed X-ray flares using simulations, scientists are learning more about their ins and outs – as well as the ultra-dense neutron stars that produce them.

Part 1

Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 12:33pm

"What makes our recent finding so special is that it shows how individual particles behave in a coupled resonance," Bartosik says. "We can demonstrate that the experimental findings agree with what had been predicted based on theory and simulation."

The next step is to develop a theory that describes how individual particles behave in the presence of an accelerator resonance. This, the researchers say, will ultimately give them a new way to mitigate beam degradation, and achieve the high-fidelity beams required for ongoing and future particle acceleration experiments.

The team's research has been published in Nature Physics.

https://www.nature.com/articles/s41567-023-02338-3

Part 4

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Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 12:33pm

"In accelerator physics, the thinking is often in only one plane," Franchetti says. In order to map a resonance, however, the particle beam needs to be measured across both the horizontal and the vertical planes.

It sounds pretty straightforward, but if you're used to thinking about something a specific way, it might take an effort to think outside the box. Understanding the effects of resonance on a particle beam took quite a few years, and some hefty computer simulations.

However, that information opened the way for Franchetti, along with physicists Hannes Bartosik and Frank Schmidt of CERN, to finally measure the magnetic anomaly.

Using beam position monitors along the Super Proton Synchrotron, they measured the position of the particles for approximately 3,000 beams. By carefully measuring where the particles were centered, or skewed to one side, they were able to generate a map of the resonance haunting the accelerator.

Part 3

Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 12:32pm

Resonance occurs when two systems interact and sync up. It could be a resonance emerging between planetary orbits as they gravitationally interact in their journey around a star, or a tuning fork that starts to sympathetically ring when sound waves from another tuning fork hit its tines.

Particle accelerators use powerful magnets that generate electromagnetic fields to guide and accelerate beams of particles to where physicists want them to go. Resonances can occur in the accelerator due to imperfections in the magnets, creating a magnetic structure that interacts with particles in problematic ways.

The more degrees of freedom a dynamic system exhibits, the more complex it is to describe mathematically. Particles moving through a particle accelerator are usually described using just two degrees of freedom, reflecting the two coordinates needed to define a point on a flat grid.

To describe structures therein requires mapping them using additional features in phase space beyond just the up-down, left-right dimensions; that is, four parameters are needed to map each point in the space.

This, the researchers say, is something that could very easily "elude our geometric intuition".

Part 2

Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 12:31pm

Physicists Capture Elusive 4D 'Ghost' in CERN Particle Accelerator

There's a specter haunting the tunnels of a particle accelerator at CERN.

In the Super Proton Synchrotron, physicists have finally measured and quantified an invisible structure that can divert the course of the particles therein, and create problems for particle research.

It's described as taking place in phase space, which can represent one or more states of a moving system. Since four states are required to represent the structure, the researchers view it as four-dimensional.

This structure is the result of a phenomenon known as resonance, and being able to quantify and measure it takes us a step closer to solving a problem universal to magnetic particle accelerators.

"With these resonances, what happens is that particles don't follow exactly the path we want and then fly away and get lost," says physicist Giuliano Franchetti of GSI in Germany. "This causes beam degradation and makes it difficult to reach the required beam parameters."

Part 1

Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 11:32am

Pregnancy advances a woman's ‘biological’ age — but giving birth turns it back

Carrying a baby creates some of the same epigenetic patterns on DNA seen in older people.

Carrying a baby in the womb leads to changes in the distribution of certain chemical markers on a pregnant person’s DNA — changes similar to those that are a hallmark of getting older. But new research shows that, several months after a person gives birth, the chemical patterns revert to an earlier state. The results strengthen previous work in mice and preliminary results in humans.

The chemical tags analysed in the study are called methyl groups, and they are added to DNA in a process called methylation. They are one example of the ‘epigenome’, features of DNA that change gene activity without altering the genetic code.
DNA-methylation patterns can be used to estimate a person’s ‘biological age’, which reflects the physiological stresses that a person’s body has accrued over time. Some research has found that biological age is a better predictor of health problems such as cardiovascular disease3 and dementia4 than a person’s chronological age.
But unlike chronological age, “biological age is quite flexible; it’s a fluid parameter. It can go up and down”.

Comment by Dr. Krishna Kumari Challa on March 26, 2024 at 11:29am

Pregnancy advances ‘biological age’
Studies in mice and humans suggest that being pregnant can increase a person’s ‘biological age’ by a couple of years — but giving birth reverses these changes. Biological age can be estimated from patterns of DNA methylation, which occurs when chemical methyl groups are added to DNA. The patterns reflect the stresses that a body accrues over time. The work supports the idea that “biological age is quite flexible; it’s a fluid parameter. It can go up and down”, says biomedical scientist Vadim Gladyshev.

https://www.nature.com/articles/d41586-024-00843-w?utm_source=Live+...

https://www.sciencedirect.com/science/article/abs/pii/S155041312400...

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