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Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:42am

Signals from distant stars connect optical atomic clocks across Earth for the first time

Using radio telescopes observing distant stars, scientists have connected optical atomic clocks on different continents.

 Marco Pizzocaro et al, Intercontinental comparison of optical atomic clocks through very long baseline interferometry, Nature Physics (2020). DOI: 10.1038/s41567-020-01038-6

In this new research, highly-energetic extragalactic radio sources replace satellites as the source of reference signals. The group of Sekido Mamoru at NICT designed two special radio telescopes, one deployed in Japan and the other in Italy, to realize the connection using the technique of Very Long Baseline Interferometry (VLBI). These telescopes are capable of observations over a large bandwidth, while antenna dishes of just 2.4 meter diameter keep them transportable.

https://phys.org/news/2020-10-distant-stars-optical-atomic-clocks.h...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:38am

Thinning forests no defence against fires

Having logging machines "thin" forest for fire reduction is largely ineffective, a new peer-reviewed, scientific study has found.

The study compared fire severity in unthinned versus thinned forest burned in the 2009 wildfires. It covered two forest types-mixed species forest and ash forest.

The scientific evidence showed that across almost every forest age and type, thinning made little difference. It actually increased the likelihood of a crown burn in older, mixed species forests, and slightly reduced the chance of crown burn in younger aged, mixed species forest.

The impact of thinning varied with forest type, the age of the forest and fire conditions.

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Across most forest types and ages, thinning had little impact on forest fire severity, although it did worsen severity in mixed species forest aged 70 years plus and did reduce it in mixed species forest aged 20-40 years. Overall, the evidence indicates thinning forests does not reduce fire risk.

Chris Taylor et al. Does forest thinning reduce fire severity in Australian eucalypt forests?, Conservation Letters (2020). DOI: 10.1111/conl.12766

https://phys.org/news/2020-10-thinning-forests-defence.html?utm_sou...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:33am

**New model may explain rarity of certain malaria-blocking mutations

A new computational model suggests that certain mutations that block infection by the most dangerous species of malaria have not become widespread in people because of the parasite's effects on the immune system.

Several protective adaptations to malaria have spread widely among humans, such as the sickle-cell mutation. Laboratory experiments suggest that certain other mutations could be highly protective against the most dangerous human-infecting malaria species, Plasmodium falciparum. However, despite being otherwise benign, these mutations have not become widespread.

To help clarify why some protective mutations may remain rare, Penman and colleagues developed a computational model that simulates the epidemiology of malaria infection, as well the evolution of protective mutations. Importantly, the model also incorporates mechanisms of adaptive immunity, in which the immune system "learns" to recognize and attack specific pathogens, such as P. falciparum.

Analysis of the model's predictions suggests that if people rapidly gain adaptive immunity to the severe effects of P. falciparum malaria, mutations capable of blocking P. falciparum infection are unlikely to spread among the population. The fewer the number of infections it takes for people to become immune to the severe effects of malaria, the less likely it is that malaria infection-blocking mutaions will arise.

understanding how humans have adapted to malaria could help open up new avenues for treatment.

 Penman BS, Gandon S (2020) Adaptive immunity selects against malaria infection blocking mutations. PLoS Comput Biol 16(10): e1008181. doi.org/10.1371/journal.pcbi.1008181

https://phys.org/news/2020-10-rarity-malaria-blocking-mutations.htm...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:30am

Human spatial memory prioritizes high calorie foods

Humans more accurately recall the locations of high calorie than low calorie foods, according to a study . The findings suggest that human spatial memory, which allows people to remember where objects are in relation to each another, has evolved to prioritize the location of high calorie foods.

The findings indicate that human spatial memory is biased towards locating high calorie foods. This bias could have helped human ancestors to survive in environments with fluctuating food availability by enabling them to efficiently locate calorie-dense foods through foraging.

Human spatial memory implicitly prioritizes high-calorie foods, Scientific Reports (2020). DOI: 10.1038/s41598-020-72570-x , www.nature.com/articles/s41598-020-72570-x

https://medicalxpress.com/news/2020-10-human-spatial-memory-priorit...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:20am

Ants adapt tool use to avoid drowning

Researchers have observed black imported fire ants using sand to draw liquid food out of containers, when faced with the risk of drowning. This is the first time this sophisticated tool use has been reported in animals.

Aiming Zhou et al, Ants adjust their tool use strategy in response to foraging risk, Functional Ecology (2020). DOI: 10.1111/1365-2435.13671

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Nanoscale machines convert light into work

Researchers have developed a tiny new machine that converts laser light into work. These optically powered machines self-assemble and could be used for nanoscale manipulation of tiny cargo for applications such as nanofluidics and particle sorting.

The work addresses a long-standing goal in the nanoscience community to create self-assembling nanoscale machines that can perform work in conventional environments such as room temperature liquids.

The machines are based on a type of matter known as optical matter in which metal nanoparticles are held together by light rather than the chemical bonds that hold together the atoms that make up typical matter.

Both the energy for assembling the machine and the power to make it work come from light. Once the laser light is introduced to a solution containing nanoparticles, the entire process occurs on its own. Although the user does not need to actively control or direct the outcome, this could readily be done to tailor the machines for various applications.

In optical matter, a laser light field creates interactions between metal nanoparticles that are much smaller than the wavelength of light. These interactions cause the particles to self-assemble into ordered arrays. This is a similar principle to optical trapping, in which light is used to hold and manipulate particles, biological molecules and cells.

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In the new work, the researchers created an optical matter machine that operates much like a mechanical machine based on interlocking gears. In such machines, when one gear is turned, a smaller interlocking gear will spin in the opposite direction. The optical matter machine uses circularly polarized light from a laser to create a nanoparticle array that acts like the larger gear by spinning in the optical field. This "optical matter gear" converts the circularly polarized light into orbital, or angular, momentum that influences a nearby probe particle to orbit the nanoparticle array (the gear) in the opposite direction.

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In previous work, the researchers discovered that when optical matter is exposed to circularly polarized light, it rotates as a rigid body in the direction opposite the polarization rotation. In other words, when the incident light  rotates one way the optical matter array responds by spinning the other. This is a manifestation of "negative torque". The researchers speculated that a machine could be developed based on this new phenomenon.

John Parker et al, An Optical Matter Machine: Angular Momentum Conversion by Collective Modes in Optically Bound Nanoparticle Arrays, Optica (2020). DOI: 10.1364/OPTICA.396147

https://phys.org/news/2020-10-nanoscale-machines.html?utm_source=nw...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:16am

**Duplications and inversions of DNA segments lead to the masculinization of female moles

Female moles are intersexual while retaining their fertility. Typical for mammals, they are equipped with two X chromosomes, but they simultaneously develop functional ovarian and testicular tissues. In female moles, both tissue types are united in one organ, the ovotestis—a feature unique among mammals.

The testicular tissue of the female mole does not produce sperm, but large amounts of the sex hormone testosterone, meaning the females have similarly high levels as the males. Presumably, this natural "doping" makes the female moles aggressive and muscular, an advantage for life underground, where they have to dig burrows and fight for resources.

Scientists are now reporting on the genetic peculiarities that lead to this characteristic sexual development in moles. According to the study, it is primarily changes in the structure of the genome that lead to altered control of genetic activity. In addition to the genetic program for testicular development, this also stimulates enzymes for male hormone production in the females.

the researchers have completely sequenced the genome of the Iberian mole (Talpa occidentalis) for the first time. Moreover, they examined the three-dimensional structure of the genome within the cell. In the nucleus, genes and their associated control sequences form regulatory domains—relatively isolated "neighborhoods" consisting of large regions where DNA sections interact frequently with each other.

In the course of the moles' evolution, then not only would individual letters of the DNA have changed, also larger pieces of the genome would have shifted.

If segments of DNA move from one location to another, completely new or reorganized regulatory domains can emerge and thus activate new genes and enhance or attenuate their expression.

When comparing the genome to that of other animals and humans, the team discovered an inversion—i.e., an inverted genomic segment—in a region known to be involved in testicular development. The inversion causes additional DNA segments to get included in the regulatory domain of the gene FGF9, which reorganizes the control and regulation of the gene. "This change is associated with the development of testicular tissue in addition to ovarian tissue in female moles.

The team also discovered a triplication of a genomic region responsible for the production of male sex hormones (androgens), more specifically the androgen production gene CYP17A1. "The triplication appends additional regulatory sequences to the gene—which ultimately leads to an increased production of male sex hormones in the ovotestes of female moles, especially more testosterone

 DOI: 10.1126/science.aaz2582 "The mole genome reveals regulatory rearrangements associated with adaptive intersexuality" Science (2020). science.sciencemag.org/cgi/doi … 1126/science.aaz2582

https://phys.org/news/2020-10-duplications-inversions-dna-segments-...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:10am

Generating photons for communication in a quantum computing system

Researchers using superconducting quantum bits connected to a microwave transmission line have shown how the qubits can generate on demand the photons, or particles of light, necessary for communication between quantum processors.

The advance is an important step toward achieving the interconnections that would allow a modular quantum computing system to perform operations at rates exponentially faster than classical computers can achieve.

 B. Kannan et al. Generating spatially entangled itinerant photons with waveguide quantum electrodynamics, Science Advances (2020). DOI: 10.1126/sciadv.abb8780

https://phys.org/news/2020-10-photons-quantum.html?utm_source=nwlet...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:06am

New method can pinpoint cracks in metal long before they cause catastrophes

Fatigue failure plagues all metals and mitigating it is of great importance.

It is the leading cause of cracks in metallic components of aircraft.

That is why it is common practice in the airline industry to adhere to regular—and expensive—replacement schedules for many parts. But the life of those parts could be more accurately determined by better understanding the origins of crack initiation.

Whether it is the pounding of vehicles on bridges or shifts in air pressure on airplanes, such continuous change called "cyclic loading" gradually induces slips in the internal molecular structure of the most durable metals until cracks occur that could have been anticipated long before their perilous appearance.

With the lack of understanding of the mechanisms that lead to crack initiation, it has been difficult to predict with any reasonable accuracy the remaining life of a cyclically loaded material. The component could actually be fine and never fail but they throw it away anyway solely on the bases of statistical arguments. That's a huge waste of money.

Most current tests to understand the origins of crack initiation have focused on the moments just prior to or after cracking to assess what happened in the makeup of the metal. And many of those tests use far larger samples that preclude tracking the initiation of damage, which is a sub-micrometer scale feature. The new method narrows the lens as small as feasible and begins when metals are first exposed to loads that lead to localized damage that could become cracks.

 "The heterogeneity of persistent slip band nucleation and evolution in metals at the micrometer scale" Science (2020). science.sciencemag.org/cgi/doi … 1126/science.abb2690

https://phys.org/news/2020-10-method-metal-catastrophes.html?utm_so...

Comment by Dr. Krishna Kumari Challa on October 8, 2020 at 7:59am

Study Points to Novel Role for Microglia in Down Syndrome

Overactive immune cells identified in a mouse model and in postmortem human brain tissue may offer a potential therapeutic target for cognitive delays associated with the condition, researchers report.

Overactivation of the brain’s immune cells, called microglia, may play a role in cognitive impairments associated with Down syndrome.

Researchers in Italy identified elevated numbers of the cells in an inflammation-promoting state in the brains of mice with a murine version of the syndrome as well as in postmortem brain tissue from people with the condition. The team additionally showed that drugs that reduce the number of activated microglia in juvenile mice could boost the animals’ performance on cognitive tests.

https://www.cell.com/neuron/fulltext/S0896-6273(20)30710-8

https://www.the-scientist.com/news-opinion/study-points-to-novel-ro...

Comment by Dr. Krishna Kumari Challa on October 8, 2020 at 7:36am

Neurobiology of conversation: Brain activity depends on who you're talking to

Our brains respond differently when talking to a person from a different socioeconomic group than during a conversation with someone of a similar background, a novel new imaging study shows.

While neuroscientists have used brain imaging scans to track in great detail neural responses of individuals to a host of factors such as stress, fear, addiction, and even love and lust, new research shows what happens in the brains of two individuals engaged in a simple social interaction.

The study reveals the distinct neurobiology of a conversation between two people of different backgrounds.

When a  professor talks to a homeless person, his or her frontal lobe activates a different neural network than if they were chatting with another colleague. Our brain has apparently designed a frontal lobe system that helps us deal with our diversity.

The researchers found that in both subjects the activity in the left dorsolateral prefrontal cortex, which is involved in control of cognitive processes, was much higher when they talked with someone from a different socioeconomic background than with someone of similar status.

There is a neurobiology of socialness, and neurobiology allows us to modulate our response to diversity.  We want to be inclusive, we want equity, and theoretically, neuroscience can say something about how we can achieve that.

https://news.yale.edu/2020/10/05/neurobiology-conversation-brain-ac...

https://researchnews.cc/news/2902/Neurobiology-of-conversation--Bra...

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