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Comment by Dr. Krishna Kumari Challa on October 8, 2020 at 5:42am

Scientists clarify how the brain separates present from past dangers

A team of neuroscientists has identified processes the brain undergoes to distinguish real and present dangers from those linked to past experiences in mice. The findings have implications for our understanding of post-traumatic stress disorder (PTSD)—an affliction marked by the inability to distinguish between past and present dangers or to recognize "safe" situations.

Memories of a traumatic episode can last for a long time. But we are able to use such memories selectively: to predict and respond to a subsequent, related danger while also recognizing when threats do not exist. This is especially important for survival behaviour in an uncertain environment such as a conflict zone or at times of social unrest.

This has significant implications for memory disorders such as PTSD, where patients have difficulty distinguishing between safety and threat cues.

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Learning to identify and appropriately respond to cues in an uncertain environment is crucial for animal survival, the researchers note. Specifically, cues that reliably predict danger prompt behaviors such as freezing in order to escape detection. However, along with the threat-predicting cues, an uncertain environment can present cues that predict safety—or, specifically, lack of danger. Animals, then, need to respond to the threat-predicting cue with defensive behaviors and, conversely, to safety cues by ceasing a threat response and resuming normal behaviors.

 the scientists sought to identify the cellular molecules, or substrates, for long-term storage of threat and safety-cue-associated memories.

It has been long established that a region of the brain, the amygdala, plays a fundamental role in the processing and storing of emotion-related information. Less understood, however, are the cellular engines and architecture that underlie it—specifically, the identity of cell types that store cue-related information and allow animals to respond appropriately even after considerable time has elapsed after the initial threat exposure.

Also well understood are the formation and consolidation of long-lasting memories, which occur through changes in the cellular landscape of proteins—a dynamic that captures significant features of an event, in part by synthesis of new proteins.

In the new work, the scientists aimed to better understand these mechanisms by disrupting key steps in protein synthesis in specific cell types—a maneuver that would reveal their significance. This procedure allowed the researchers to identify key players in this intricate process.

Amygdala inhibitory neurons as loci for translation in emotional memories, Nature (2020). DOI: 10.1038/s41586-020-2793-8 , www.nature.com/articles/s41586-020-2793-8

https://medicalxpress.com/news/2020-10-scientists-brain-dangers.htm...

Comment by Dr. Krishna Kumari Challa on October 8, 2020 at 5:33am

2 scientists win Nobel chemistry prize for gene-editing tool

The Nobel Prize in chemistry went to two researchers Wednesday for a gene-editing tool that has revolutionized science by providing a way to alter DNA, the code of life—technology already being used to try to cure a host of diseases and raise better crops and livestock.

Emmanuelle Charpentier  and Jennifer A. Doudna  won for developing CRISPR-cas9, a very simple technique for cutting a gene at a specific spot, allowing scientists to operate on flaws that are the root cause of many diseases.

Announcement of the 2020 Nobel Prize in Chemistry

https://phys.org/news/2020-10-nobel-prize-chemistry-awarded-charpen...

Comment by Dr. Krishna Kumari Challa on October 8, 2020 at 5:28am

Quantum heat engine behaviour observed in a qubit

Although many of today's accepted theories of classical thermodynamics predate even the industrial revolution they helped to propel, many open questions remain around how these ideas translate to the level of single quantum systems. In particular, the potential for superposition of states has as yet unexplored implications for thermodynamic behavior. Now, a collaboration of researchers has produced a quantum device that can not only behave analogously to a heat engine and a refrigerator, but also a superposition of both at the same time.

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They came together to examine the behavior of qubits based on impurities in silicon for quantum interferometry before turning their attention to how the behavior of these systems might resemble classical heat engines.

 K. Ono et al. Analog of a quantum heat engine using a single-spin qubit, Physical Review Letters (2020). Accepted manuscript: journals.aps.org/prl/accepted/ … b682605ce40bdae2719c

https://phys.org/news/2020-10-quantum-behaviour-qubit.html?utm_sour...

Comment by Dr. Krishna Kumari Challa on October 7, 2020 at 9:01am

Himalayan glaciers melting because of high-altitude dust

Desert dust from as far away as Saudi Arabia gets picked up by winds that carry it to the snowpack of the Himalayas, where it accelerates glacial warming and snowmelt, scientists say. 

Himalayan glaciers melting because of high-altitude dust

Dust, climate change and air pollution are triple threat to water source for a billion people

https://newsroom.ucla.edu/releases/dust-in-the-wind-is-making-himal...

https://researchnews.cc/news/2886/Himalayan-glaciers-melting-becaus...

Comment by Dr. Krishna Kumari Challa on October 7, 2020 at 8:54am

Study solves an HIV mystery

In some patients with HIV who take medication, the virus still shows up in their blood. A study  has found “repliclones”—large clones of HIV-infected cells that produce infectious virus particles—are to blame.

A patient with HIV who insists they are adhering to the daily medication regimen meant to keep the virus in check, but testing says otherwise. It seems the virus is still showing up in the patient’s blood, which clinicians thought couldn’t happen when the infection is controlled with medication. scientists report that they’ve solved the mystery—and the answer has clinical implications.

In a study  infectious disease researchers show that the issue isn’t nonadherence to medication or resistance to the drugs. Instead, the patients are victims of what the scientists have dubbed “repliclones”—large clones of HIV-infected cells that produce infectious virus particles.

Repliclones can grow large enough and produce enough virus to make it appear that antiretroviral therapy isn’t working completely even when it is.--

In short, rather than the virus infecting new cells, already infected HIV-producing cells are growing into large clones that make and release virus. Current medications for HIV infection block the virus from infecting new cells but don’t affect virus production from cells or clones of cells that are already infected.

HIV replicates by taking over a cell’s machinery and using it to produce more virus, which can then go on to infect other cells. Antiretroviral therapy, which is taken daily, prevents the virus from infecting new cells. So, even though HIV can’t yet be cured, it can be controlled to the point that it isn’t detectable in blood tests.

https://www.upmc.com/media/news/100520-mellors-replicones

https://researchnews.cc/news/2885/Study-solves-an-HIV-mystery#.X31H...

Comment by Dr. Krishna Kumari Challa on October 7, 2020 at 8:27am

Scientists unravel the mystery behind new plant species found in the Swiss Alps, which only took 150 years to evolve

A new plant species in Swiss alps Cardamine insueta

took only 150years to evolve. Scientists think this is because of traits C. insueta inherited from its parent plants - each with its own distinct habitat. Depending on the environmental situation, the plant activates a different set of genes it inherited from its two parent species.

ORIGINAL RESEARCH ARTICLE

Front. Genet., 06 October 2020 | https://doi.org/10.3389/fgene.2020.567262

https://www.frontiersin.org/articles/10.3389/fgene.2020.567262/full
https://www.businessinsider.in/science/biology/news/new-swiss-alps-...

Comment by Dr. Krishna Kumari Challa on October 7, 2020 at 7:11am

Researchers crack quantum physics puzzle

Scientists have re-investigated a sixty-year-old idea by an American physicist and provided new insights into the quantum world.

The research could lead to improved spectroscopic techniques, laser techniques, interferometric high-precision measurements and atomic beam applications.

Quantum physics is the study of everything around us at the atomic level, atoms, electrons and particles. Atoms and electrons which are so small, one billion placed side by side could fit within a centimeter. Because of the way atoms and electrons behave, scientists describe their behaviour as like waves.

Waves, unlike particles which travel in straight lines, can go around obstacles, but if there are enough random obstacles, the waves cannot get through because they interfere with each other and cancel themselves out.

At low temperatures, matter, which is made up of atoms and particles, can be made to behave much like light; that is, light behaves the same way all waves do whether it be light waves or ocean waves. In its interaction with matter, light can behave like it is composed of particles which don't go around objects but instead travel in a straight line.

In the Quantum Information Lab researchers took this one step further and added an ultra-cold atom experiment to the mix. With the aid of high tech lasers, they manipulated these ultra-cold atoms until they were so cold, their wave behaviour became visible to the eye.

This is about a billionth of a degree above absolute zero (-273.15 degrees C) so that is pretty chilly. Physicists have created customized patterns of obstacles to stop the waves, and when they take a picture, they can find out where these atoms are. This way, they can see what exactly is required to get their quantum-mechanical waves to reflect off obstacles, and why the waves do not get in.

Donald H. White et al. Observation of two-dimensional Anderson localisation of ultracold atoms, Nature Communications (2020). DOI: 10.1038/s41467-020-18652-w

https://phys.org/news/2020-10-quantum-physics-puzzle.html?utm_sourc...

 

Comment by Dr. Krishna Kumari Challa on October 7, 2020 at 6:35am

**A new interpretation of quantum mechanics suggests that reality does not depend on the person measuring it

Quantum mechanics arose in the 1920s, and since then scientists have disagreed on how best to interpret it. Many interpretations, including the Copenhagen interpretation presented by Niels Bohr and Werner Heisenberg, and in particular, von Neumann-Wigner interpretation, state that the consciousness of the person conducting the test affects its result. On the other hand, Karl Popper and Albert Einstein thought that an objective reality exists. Erwin Schrödinger put forward the famous thought experiment involving the fate of an unfortunate cat that aimed to describe the imperfections of quantum mechanics.

In their most recent article, Finnish civil servants Jussi Lindgren and Jukka Liukkonen, who study quantum mechanics in their free time, take a look at the uncertainty principle that was developed by Heisenberg in 1927. According to the traditional interpretation of the principle, location and momentum cannot be determined simultaneously to an arbitrary degree of precision, as the person conducting the measurement always affects the values.

However, in their study Lindgren and Liukkonen concluded that the correlation between a location and momentum, i.e., their relationship, is fixed. In other words, reality is an object that does not depend on the person measuring it. Lindgren and Liukkonen utilized stochastic dynamic optimization in their study. In their theory's frame of reference, Heisenberg's uncertainty principle is a manifestation of thermodynamic equilibrium, in which correlations of random variables do not vanish.

"The results suggest that there is no logical reason for the results to be dependent on the person conducting the measurement. According to our study, there is nothing that suggests that the consciousness of the person would disturb the results or create a certain result or reality

This interpretation supports such interpretations of quantum mechanics that support classical scientific principles.

"The interpretation is objective and realistic, and at the same time as simple as possible. We like clarity and prefer to remove all mysticism

Jussi Lindgren et al. The Heisenberg Uncertainty Principle as an Endogenous Equilibrium Property of Stochastic Optimal Control Systems in Quantum Mechanics, Symmetry (2020). DOI: 10.3390/sym12091533

https://phys.org/news/2020-10-quantum-mechanics-reality-person.html...

Comment by Dr. Krishna Kumari Challa on October 7, 2020 at 6:26am

**Individual suicide risk can be dramatically altered by social 'sameness,' study finds

Similarities among individuals living in the same communities can dramatically change their risk of dying by suicide, according to a new study

Bernice A. Pescosolido et al, Cross-level sociodemographic homogeneity alters individual risk for completed suicide, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2006333117

https://phys.org/news/2020-10-individual-suicide-social-sameness.ht...

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Safeguarding iconic buildings from bomb explosions

 Researchers have developed a technique to prevent glass facades on iconic buildings from shattering if the building is targeted by terrorists in a bomb explosion.

In the study researchers looked at the "maximum credible load" of an explosion and how to minimize the problem of a deadly wave of shattered glass which can cause traumatic injury and death.

The study went beyond previous research in the field with a sophisticated coupling analysis, which did not just look at the way the glass responds to an explosion but also modeled the explosive source, the pressure wave transmission and fluid-structure interaction.

The researchers modeled the shock waves that traveled through the air and then they studied how it hit the structures.

The solution is to absorb the energy of the blast with a shock absorbing layer between the glass panels in the laminated glass and through the members of the supporting system as well as to make the cable trusses stronger. The glass is certainly going to crack, but this interlayer holds the particles together.

 R.R.C. Piyasena et al. Fully coupled modeling technique for blast analysis of cable truss facades, Engineering Failure Analysis (2020). DOI: 10.1016/j.engfailanal.2020.104771

https://techxplore.com/news/2020-10-safeguarding-iconic-explosions....

Comment by Dr. Krishna Kumari Challa on October 7, 2020 at 6:20am

Deciphered: evolution of the Y chromosome in great apes 

New analysis of the DNA sequence of the male-specific Y chromosomes from all living species of the great ape family helps to clarify our understanding of how this enigmatic chromosome evolved. A clearer picture of the evolution of the Y chromosome is important for studying male fertility in humans as well as our understanding of reproduction patterns and the ability to track male lineages in the great apes, which can help with conservation efforts for these endangered species.

A team of biologists and computer scientists sequenced and assembled the Y chromosome from orangutan and bonobo and compared those sequences to the existing human, chimpanzee, and gorilla Y sequences. From the comparison, the team were able to clarify patterns of evolution that seem to fit with behavioural differences between the species and reconstruct a model of what the Y chromosome might have looked like in the ancestor of all great apes.

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The Y chromosome is important for male fertility and contains the genes critical for sperm production, but it is often neglected in genomic studies because it is so difficult to sequence and assemble . The Y chromosome contains a lot of repetitive sequences, which are challenging for DNA sequencing, assembling sequences, and aligning sequences for comparison. There aren't out-of-the-box software packages to deal with the Y chromosome, so we had to overcome these hurdles and optimize our experimental and computational protocols, which allowed us to address interesting biological questions.

The Y chromosome is unusual. It contains relatively few genes, many of which are involved in male sex determination and sperm production; large sections of repetitive DNA, short sequences repeated over and over again; and large DNA palindromes, inverted repeats that can be many thousands of letters long and read the same forwards and backwards.

Previous work by the team comparing human, chimpanzee, and gorilla sequences had revealed some unexpected patterns. Humans are more closely related to chimpanzees, but for some characteristics, the human Y was more similar to the gorilla Y.

Monika Cechova et al, Dynamic evolution of great ape Y chromosomes, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2001749117

https://phys.org/news/2020-10-evolution-chromosome-great-apes-decip...

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