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Comment by Dr. Krishna Kumari Challa on October 29, 2020 at 6:49am

Researchers break magnetic memory speed record

Spintronic devices are attractive alternatives to conventional computer chips, providing digital information storage that is highly energy efficient and also relatively easy to manufacture on a large scale. However, these devices, which rely on magnetic memory, are still hindered by their relatively slow speeds, compared to conventional electronic chips.

Now an international team of researchers has reported a new technique for magnetization switching—the process used to "write" information into magnetic memory—that is nearly 100 times faster than state-of-the-art spintronic devices. The advance could lead to the development of ultrafast magnetic memory for computer chips that would retain data even when there is no power.

In the study, the researchers report using extremely short, 6-picosecond electrical pulses to switch the magnetization of a thin film in a magnetic device with great energy efficiency. A picosecond is one-trillionth of a second.

 Kaushalya Jhuria et al. Spin–orbit torque switching of a ferromagnet with picosecond electrical pulses, Nature Electronics (2020). DOI: 10.1038/s41928-020-00488-3

https://techxplore.com/news/2020-10-magnetic-memory.html?utm_source...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 1:21pm

**'Fireball' meteorite contains pristine extraterrestrial organic compounds

O n the night of January 16, 2018, a fireball meteor streaked across the sky over the Midwest and Ontario before landing on a frozen lake in Michigan. Scientists used weather radar to find where the pieces landed and meteorite hunters were able to collect the meteorite quickly, before its chemical makeup got changed by exposure to liquid water. And, as a new paper in Meteoritics & Planetary Science shows, that gave scientists a glimpse of what space rocks are like when they're still in outer space—including a look at pristine organic compounds that could tell us about the origins of life.

This meteorite is special because it fell onto a frozen lake and was recovered quickly. It was very pristine. Researchers could see the minerals weren't much altered and later found that it contained a rich inventory of extraterrestrial organic compounds. These kinds of organic compounds were likely delivered to the early Earth by meteorites and might have contributed to the ingredients of life.

Scientists aren't sure how the organic (carbon-containing) compounds responsible for life on Earth got here; one theory is that they hitched their way here on meteorites. That doesn't mean that the meteorites themselves contain extraterrestrial life; rather, some of the organic compounds that help make up life might have first formed in an asteroid that later fell to Earth.

As soon as the thing lands, it gets covered with microbes and life from Earth. We have meteorites with lichens growing on them. So the fact that this meteorite was collected so quickly after it fell, and that it landed on ice rather than in the dirt, helped keep it cleaner.

https://phys.org/news/2020-10-fireball-meteorite-pristine-extraterr...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 1:15pm

60-year-old limit to lasers overturned by quantum researchers

A team of Australian quantum theorists has shown how to break a bound that had been believed, for 60 years, to fundamentally limit the coherence of lasers.

The coherence of a laser beam can be thought of as the number of photons (particles of light) emitted consecutively into the beam with the same phase (all waving together). It determines how well it can perform a wide variety of precision tasks, such as controlling all the components of a quantum computer.

Now, in a paper published in Nature Physics, the researchers from Griffith University and Macquarie University have shown that new quantum technologies open the possibility of making this coherence vastly larger than was thought possible.

It 's shown now that  the true limit imposed by quantum mechanics is that the coherence cannot be greater than the fourth power of the number of photons stored in the laser.

 Travis J. Baker et al. The Heisenberg limit for laser coherence, Nature Physics (2020). DOI: 10.1038/s41567-020-01049-3

https://phys.org/news/2020-10-year-old-limit-lasers-overturned-quan...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 1:03pm

Random effects key to containing epidemics

To control an epidemic, authorities will often impose varying degrees of lockdown. In a paper in the journal Chaos, scientists have discovered, using mathematics and computer simulations, why dividing a large population into multiple subpopulations that do not intermix can help contain outbreaks without imposing contact restrictions within those local communities.

The key idea is that, at low infection numbers, fluctuations can alter the course of the epidemics significantly, even if you expect an exponential increase in infection numbers on average. 

When infection numbers are high, random effects can be ignored. But subdividing a population can create communities so small that the random effects matter.

When a large population is divided into smaller communities, these random effects completely change the dynamics of the full population. Randomness causes peak infection numbers to be brought way down.

"Stochastic effects on the dynamics of an epidemic due to population subdivision," Chaos (2020). DOI: 10.1063/5.0028972

https://phys.org/news/2020-10-random-effects-key-epidemics.html?utm...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:59pm

Asymptomatic virus sufferers lose antibodies sooner: study

Asymptomatic coronavirus sufferers appear to lose detectable antibodies sooner than people who have exhibited COVID-19 symptoms, according to one of the biggest studies of its kind

https://medicalxpress.com/news/2020-10-asymptomatic-virus-antibodie...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:43pm

Why do certain chemotherapies increase the likelihood of blood cancer?

One rare complication of cancer treatment is the development of a secondary blood cancer—therapy-related acute myeloid leukemia or myelodysplastic syndrome. These blood cancers are very aggressive and do not respond well to treatment. Historically, doctors thought that cancer treatments such as chemotherapy and radiation caused an accumulation of mutations in the blood that led to these therapy-related cancers.

In recent years, however, researchers have found that these mutations in the blood can also occur spontaneously with increasing age. This phenomenon is called clonal hematopoiesis (CH), and it's found in 10 to 20% of all people over age 70. The presence of CH increases the risk of developing a blood cancer. Using data from MSK-IMPACTTM, Memorial Sloan Kettering's clinical genomic sequencing test, researchers have shown that CH is also frequent in cancer patients.

Focusing on a subset of patients on whom they had more detailed data, the investigators observed increased rates of CH in people who had already received treatment. They made specific connections between cancer therapies such as radiation therapy and particular chemotherapies—for example certain platinum drugs or agents called topoisomerase II inhibitors—and the presence of CH.

Unlike the CH changes found in the general population, the team found that CH mutations after cancer treatment occur most frequently in the genes whose protein products protect the genome from damage. One of these genes is TP53, which is frequently referred to as "the guardian of the genome."

This finding provides a direct link between mutation type, specific therapies, and how these cells progress towards becoming a blood cancer.

 Kelly L. Bolton et al. Cancer therapy shapes the fitness landscape of clonal hematopoiesis, Nature Genetics (2020). DOI: 10.1038/s41588-020-00710-0

https://medicalxpress.com/news/2020-10-chemotherapies-likelihood-bl...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:36pm

Vampire bats social distance when they get sick

 Wild vampire bats that are sick spend less time near others from their community, which slows how quickly a disease will spread.

As a pathogen spreads across a population, changes in social behaviour can alter how the disease spreads. Transmission rates can increase when parasites change host behaviour or decrease when healthy individuals avoid sick ones. In certain social insects, sick ones might self-isolate voluntarily or be excluded by their colony mates. A simpler mechanism causing reduced transmission is that infected animals often show sickness behaviour, which includes increased lethargy and sleep, and reduced movement and sociality. This sickness-induced social distancing does not require cooperation from others and is probably common across species.

 "Tracking sickness effects on social encounters via continuous proximity-sensing in wild vampire bats" Behavioral Ecology (2020). DOI: 10.1093/beheco/araa111

https://phys.org/news/2020-10-vampire-social-distance-sick.html?utm...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:33pm

The experimental demonstration of entanglement between mechanical and spin systems

Quantum entanglement is the basic phenomenon underlying the functioning of a variety of quantum systems, including quantum communication, quantum sensing and quantum computing tools. This phenomenon results from an interaction (i.e., entanglement) between particles. Attaining entanglement between distant and very different objects has  proved highly challenging till now.

Researchers  have recently generated entanglement between a mechanical oscillator and a collective atomic spin oscillator. Their work introduces a strategy for generating entanglement between these two distinct systems.

To generate entanglement between a mechanical and a spin system, Polzik and his colleagues leveraged a key feature of spin oscillators, namely that they can have an effective negative mass. When it is excited, a spin oscillator's energy is reduced, which allows it to become entangled with a more conventional mechanical oscillator that has a positive mass. The researchers experimentally generated this entanglement by performing a joint measurement on both oscillators.

Entanglement between distant macroscopic mechanical and spin systems. Nature Physics (2020). DOI: 10.1038/s41567-020-1031-5.

https://phys.org/news/2020-10-experimental-entanglement-mechanical....

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:11pm

Scientists develop genetic 'monitors' that detect when genes are active
Genetic sensors that can detect the activity from genes, rather than just the genes themselves, have been developed by a team of scientists.

Based on the CRISPR gene editing system, the scientists have developed microscopic machines that use these sensors to detect when genes are ‘on’ or ‘off’ inside a cell, and react to those changes dynamically - making them a potentially ideal monitoring system.

These genetic sensors are detailed in a new paper published in The CRISPR Journal, where the scientists demonstrate a genetic device based on the CRISPR system inside a bacterial cell. The work is the first step in scientists developing genetic devices that can make changes to gene expression after sensing the existing gene activity within a cell.

Cells contain a number of genes that are expressed to perform numerous functions, from sensing their environment and processing food. By having a sensor that can detect when those genes are active, scientists could program a machine to react to a specific process, such as when the cell digests its food.

To generate these novel genetic devices, the scientists used as a scaffold the programmable part of CRISPR which is also responsible for sequence recognition and binding, called guide RNA sequence (gRNA). They were able to redesign the gRNA sequence by introducing in it a sensor so that the CRISPR complex would be able to bind the DNA target only after being activated by a trigger signal, such as short segments of viral RNA sequences. The sensor can be triggered by any chosen RNA sequence and in this way it activates a CRISPR system at any point of the life cycle of a cell or virus.

https://warwick.ac.uk/newsandevents/pressreleases/scientists_develo...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 11:57am

COVID-19

Get the latest information from the MoHFW about COVID-19.

Neuropilin-1 drives SARS-CoV-2 infectivity

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