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Comment by Dr. Krishna Kumari Challa on December 22, 2020 at 8:37am

Current food production systems could mean far-reaching habitat loss

The global food system could drive rapid and widespread biodiversity loss if not changed, new research has found.

The findings show that the global food system will need to be transformed to prevent habitat loss across the world. It shows that what we eat and how it is produced will need to change rapidly and dramatically to prevent widespread and severe biodiversity losses.

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The study estimated how food systems would affect biodiversity at a finer spatial scale than previous research (2.25 km²), making the results more relevant to conservation action by highlighting exactly which species and landscapes are likely to be threatened.

It did so by linking projections of how much agricultural land each country will need with a new model that estimates where agricultural expansion and abandonment are most likely to occur.

Proactive conservation to prevent habitat losses to agricultural expansion, Nature Sustainability (2020). DOI: 10.1038/s41893-020-00656-5 , www.nature.com/articles/s41893-020-00656-5

https://phys.org/news/2020-12-current-food-production-far-reaching-...

Comment by Dr. Krishna Kumari Challa on December 22, 2020 at 8:05am

When T-cells of our immune system become active, tiny traction forc...

When T-cells of our immune system become active, tiny traction forces at the molecular level play an important role. They have now been studied at TU Wien.

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Brazilian forests found to be transitioning from carbon sinks to ca...

A team of researchers affiliated with several institutions in Brazil has found that some non-Amazonian forests in Brazil have already begun to transition from carbon sinks to carbon sources. In their paper published in the journal Science Advances, the group describes their 33-year study of deciduous, semi-deciduous and evergreen forests in Brazil's state of Minas Gerais.

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Comment by Dr. Krishna Kumari Challa on December 22, 2020 at 8:02am

Evolution of a killer: How African Salmonella made the leap from gut to bloodstream

Scientists have exploited the combined power of genomics and epidemiology to understand how a type of Salmonella bacteria evolved to kill hundreds of thousands of immunocompromised people.

Bloodstream infections caused by a drug-resistant type of Salmonella Typhimurium called ST313 are a major public health concern in Africa, where the disease is endemic and causes ~50,000 deaths each year. What was missing was an understanding of the timing of the major evolutionary events that equipped African Salmonella to cause bloodstream infections in humans.

A team of researchers  sampled two comprehensive collections of Salmonella isolates from African patients with bloodstream infections, spanning 1966 to 2018, to piece together the evolutionary journey of the Salmonella over 50 years of human infections in Africa, including the discovery of a new lineage of antibiotic-susceptible ST313.

In the study, scientists sequenced the genomes of 680 Salmonella isolates, from archives kept by the Malawi Liverpool Wellcome Trust (MLW) clinical research programme and the Institute Pasteur, and used them to uncover the timeline of crucial genetic events responsible for the infection of immunocompromised humans by S. Typhimurium ST313. Mutations that influenced gene function during the evolution of ST313 were identified for the first time.

The team also discovered a new antibiotic-susceptible lineage of ST313 that emerged in Malawi in 2016 and is closely related to Salmonella variants that cause stomach infections in the United Kingdom and Brazil. The researchers speculate that changes in antibiotic usage in Malawi between 2002 and 2015 could have created a window of opportunity for the emergence of this new antibiotic-susceptible ST313 lineage.

Stepwise evolution of Salmonella Typhimurium ST313 causing bloodstream infection in Africa, Nature Microbiology (2020). DOI: 10.1038/s41564-020-00836-1 , www.nature.com/articles/s41564-020-00836-1

https://phys.org/news/2020-12-evolution-killer-african-salmonella-g...

Comment by Dr. Krishna Kumari Challa on December 21, 2020 at 10:40am

AI-powered microscope could check cancer margins in minutes

When surgeons remove cancer, one of the first questions is, “Did they get it all?” Researchers from Rice University and the University of Texas MD Anderson Cancer Center have created a new microscope that can quickly and inexpensively image large tissue sections, potentially during surgery, to find the answer. The microscope can rapidly image relatively thick pieces of tissue with cellular resolution, and could allow surgeons to inspect the margins of tumors within minutes of their removal. It was created by engineers and applied physicists at Rice and is described in a study published this week in the Proceedings of the National Academy of Sciences.

http://news.rice.edu/2020/12/17/ai-po...

Comment by Dr. Krishna Kumari Challa on December 21, 2020 at 10:08am

Fast walking in narrow corridors can increase COVID-19 transmission risk

Computational simulations have been used to accurately predict airflow and droplet dispersal patterns in situations where COVID-19 might be spread. In the journal Physics of Fluids, results show the importance of the shape of the space in modeling how virus-laden droplets move through the air.

The simulations are used to determine flow patterns behind a walking individual in spaces of different shape. The results reveal a higher transmission risk for children in some instances, such as behind quickly moving people in a long narrow hallway.

Previous investigations using this simulation technique have helped scientists understand the influence of objects, like glass barriers, windows, air conditioners, and toilets, on airflow patterns and virus spread. The previous simulations have usually assumed a large, open indoor space but have not considered the effect of nearby walls, like those that might exist in a narrow corridor.

If a person walking in a corridor coughs, their breath expels droplets that travel around and behind their body, forming a wake in the way a boat forms a wake in water as it travels. The investigation revealed the existence of a "re-circulation bubble" directly behind the person's torso and a long wake streaming out behind them at approximately waist height.

The flow patterns found are strongly related to the shape of the human body. At 2 meters downstream, the wake is almost negligible at mouth height and leg height but is still visible at waist height. 

Once the airflow patterns were determined, the investigation modeled the dispersal of a cloud of droplets expelled from the simulated person's mouth. The shape of the space surrounding the moving person is particularly critical for this part of the calculation.

Two types of dispersal modes were found. In one mode, the cloud of droplets detaches from the moving person and floats far behind that individual, creating a floating bubble of virus-laden droplets. In the other mode, the cloud is attached to the person's back, trailing behind them like a tail as they move through the space.

For the detached mode, the droplet concentration is much higher than for the attached mode, five seconds after a cough. This poses a great challenge in determining a safe social distance in places like a very narrow corridor, where a person may inhale viral droplets even if the patient is far in front of him or her.

The danger is particularly great for children, since in both modes, the cloud of droplets hovers at a distance above the ground that is about half the height of the infected person—in other words, at mouth level for children.

"Effects of space sizes on the dispersion of cough-generated droplets from a walking person," Physics of Fluids (2020). aip.scitation.org/doi/10.1063/5.0034874

https://phys.org/news/2020-12-fast-narrow-corridors-covid-transmiss...

Comment by Dr. Krishna Kumari Challa on December 20, 2020 at 12:29pm

Quantum Experiment Reveals Particles Can Form Collectives Out of Almost Nothing

How many particles do you need before individual atoms start behaving collectively? According to new research, the number is incredibly low. As few as six atoms will start transitioning into a macroscopic system, under the right conditions.

Using a specially designed ultra-cold laser trap, physicists observed the quantum precursor of the transition from a normal to a superfluid phase – offering a way to study the emergence of collective atomic behaviour and the limits of macroscopic systems.

Many-body physics is the field that seeks to describe and understand the collective behaviour of large numbers of particles: a bucket of water, for example, or a canister of gas. We can describe these substances in terms of their density, or their temperature – the way the substance is acting as a whole.

These are called macroscopic or many-body systems, and we can't understand them by just studying the behaviour of individual atoms or molecules. Rather, their behaviour emerges from the interactions between particles that individually do not have the same properties of the system as a whole.

Some examples of macroscopic behaviours that can't be described microscopically include collective excitations, such as the phonons that oscillate atoms in a crystal lattice. Phase transitions are another example – when a substance transitions from one phase to another – such as when ice melts into liquid, for example, or when liquid evaporates into a gas.

https://www.nature.com/articles/s41586-020-2936-y

https://www.sciencealert.com/quantum-simulator-reveals-that-phase-t...

 Here we observe the few-body precursor of a quantum phase transition from a normal to a superfluid phase. The transition is signalled by the softening of the mode associated with amplitude vibrations of the order parameter, usually referred to as a Higgs mode⁷. We achieve fine control over ultracold fermions confined to two-dimensional harmonic potentials and prepare closed-shell configurations of 2, 6 and 12 fermionic atoms in the ground state with high fidelity. 

Comment by Dr. Krishna Kumari Challa on December 19, 2020 at 12:38pm

Comment by Dr. Krishna Kumari Challa on December 19, 2020 at 12:35pm

Colorful, magnetic Janus balls could help foil counterfeiters

Counterfeiters who sell knockoffs of popular shoes, handbags and other items are becoming increasingly sophisticated, forcing manufacturers to find new technologies to stay one step ahead. Now, researchers reporting in ACS Nano have developed tiny Janus balls that show their colored side under a magnetic field. These microparticles could be useful in inks for anti-counterfeiting tags, which could be verified with an ordinary magnet, the researchers say. 

Janus balls are microspheres that have two sides with distinct properties. Researchers wanted to make Janus balls out of two unmixable resins: one that contained magnetic nanoparticles, and another that contained silica particles. The magnetic side of the ball would also contain carbon black, causing that hemisphere to appear dark, whereas the silica particles on the other side of the ball would self-assemble into a crystalline lattice, producing structural colors. The result would be tiny balls that normally have their black sides facing up, except when a magnetic field causes them to flip to their colorful sides.

To make Janus balls, the researchers used a microfluidic device to unite drops of the two resins, with a surfactant added to stabilize the joined drops into a spherical shape. Because the silica-containing colored side of the drops was heavier than the black magnetic side, the force of gravity caused the black side to spontaneously face upward, like a roly-poly toy, when the balls were placed in water. Then, the researchers permanently aligned the magnetic nanoparticles in the balls in the same direction. By applying a magnetic field in the opposite direction, they could flip the balls to their colored sides. The researchers made red and green Janus balls by using different sizes of silica particles, with their magnetic nanoparticles aligned in opposite directions. By changing the direction of the applied magnetic field, they could change the colors of 3D-printed chameleon and butterfly shapes. Using different colors and orientations of Janus balls in inks could produce sophisticated, user-interactive anti-counterfeiting tags, the researchers say.

https://www.acs.org/content/acs/en/pressroom/presspacs/2020/acs-pre...

Comment by Dr. Krishna Kumari Challa on December 19, 2020 at 12:19pm

 Kangaroos really can 'talk' to us, study finds

Kangaroos can intentionally communicate with humans, research reveals

Animals that have never been domesticated, such as kangaroos, can intentionally communicate with humans, challenging the notion that this behavior is usually restricted to domesticated animals like dogs, horses or goats, a new study has found.

The research which involved kangaroos, marsupials that were never domesticated, at three locations across Australia, revealed that kangaroos gazed at a human when trying to access food which had been put in a closed box. The kangaroos used gazes to communicate with the human instead of attempting to open the box themselves, a behaviour that is usually expected for domesticated animals.

1. Alan G. McElligott, Kristine H. O'Keeffe, Alexandra C. Green. Kangaroos display gazing and gaze alternations during an unsolvable problem task. Biology Letters, 2020; 16 (12): 20200607 DOI: 10.1098/rsbl.2020.0607

https://www.sciencedaily.com/releases/2020/12/201217135258.htm

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https://theconversation.com/coronavirus-new-variant-genomics-resear...

Coronavirus new variant – genomics researcher answers key questions

Comment by Dr. Krishna Kumari Challa on December 19, 2020 at 12:04pm

Forensic science: laser technique distinguishes human and animal blood

New research published recently could soon offer law enforcement another valuable crime scene tool—a quick and accurate way to distinguish human blood from animal blood.

In a proof-of-concept study researchers used laser technology to rapidly differentiate human blood samples from nearly a dozen animal species.

This could prove to be key in car crash investigations when the suspect is unsure if a human or animal was struck.

technique relies on Raman spectroscopy, which works by shining a laser on a dry blood sample and measuring the interaction. No two samples produce the same results, offering a unique measurement (similar to a fingerprint). The results are instantaneous and do not destroy the sample, preserving it for future testing.

In the new study researchers used attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy, a complementary technique to Raman spectroscopy, on 15 human blood samples and a total of 89 cat, dog, rabbit, horse, cow, pig, opossum and raccoon blood samples. Although each sample  appeared nearly identical to the naked eye, the ATR FT-IR spectroscopy analysis, coupled with advanced statistics, was able to classify them as human or animal with 100 percent accuracy.

Samples from three other species—deer, elk and ferret—were included to further test the statistical model, and were all correctly classified.

Ewelina Mistek-Morabito et al. Discrimination between human and animal blood by attenuated total reflection Fourier transform-infrared spectroscopy, Communications Chemistry (2020). DOI: 10.1038/s42004-020-00424-8

https://phys.org/news/2020-12-forensic-chemist-laser-technique-dist...

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