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Comment by Dr. Krishna Kumari Challa on December 11, 2024 at 9:53am

Tourism leads the pack in growing carbon emissions, study shows

A University of Queensland-led study shows greenhouse gas emissions from tourism have been growing more than two times faster than those from the rest of the global economy. The research is published in Nature Communications.

Rapid expansion in travel demand has meant carbon  from tourism activities accounts for 9% of the world's total emissions.

Without urgent interventions in the global tourism industry, we anticipate annual increases in emissions of 3 to 4%, meaning they will double every 20 years, say scientists.

This does not comply with the Paris Agreement which requires the sector to reduce its emissions by more than 10% annually.

"The major drivers behind the increasing emissions are slow technology improvements and a rapid growth in demand.

The study involved researchers from UQ, Griffith University, the University of Sydney and Linnaeus University (Sweden), and tracked international and domestic travel for 175 countries.

It found tourism's global carbon footprint increased from 3.7 gigatons (Gt) to 5.2 Gt between 2009 and 2019. The most net emissions were reported in aviation, utilities and private vehicle use for travel.

The emissions growth rate for tourism was 3.5% per annum during the decade while global emissions increased by 1.5% per annum from 50.9 Gt to 59.1 Gt.

The United States, China, and India dominated the list and were responsible for 60% of the total increase in tourism emissions across the study period. Australia ranked in the top 20 countries that together contributed three quarters of the total tourism carbon footprint in 2019.

The biggest carbon challenge in tourism is air travel.

Reducing long-haul flights is one of the recommendations scientists have put forward to help the industry lower its emissions.

Cutting back on marketing long-haul travel and identifying a national growth threshold would also help rein in the rapid expansion of emissions.

At a local level, tourism operators could look to renewable electricity for accommodation, food and recreational activities and switch to electric vehicles for transport.

Ya-Yen Sun, Drivers of global tourism carbon emissions, Nature Communications (2024). DOI: 10.1038/s41467-024-54582-7. www.nature.com/articles/s41467-024-54582-7

Comment by Dr. Krishna Kumari Challa on December 11, 2024 at 9:36am

The team conducted their experiments at the National High Magnetic Field Laboratory in Florida. The lab's hybrid magnet creates the most powerful sustained magnetic field in the world, roughly 900,000 times stronger than the Earth's magnetic field. The field is so strong it can levitate small objects such as water droplets.

The researchers cooled down a piece of ZrSiS to -452°F—only a few degrees above absolute zero, the lowest possible temperature—and then exposed it to the lab's powerful magnetic field while hitting it with infrared light to see what it revealed about the quantum interactions inside the material.
When a magnetic field is applied to any material, the energy levels of electrons inside that material become quantized into discrete levels called Landau levels.
The levels can only have fixed values, like climbing a set of stairs with no little steps in between. The spacing between these levels depends on the mass of the electrons and the strength of the magnetic field, so as the magnetic field increases, the energy levels of the electrons should increase by set amounts based entirely on their mass—but in this case, they didn't.

Using the high-powered magnet in Florida, the researchers observed that the energy of the Landau level transitions in the ZrSiS crystal followed a completely different pattern of dependence on the magnetic field strength. Years ago, theorists had labeled this pattern the "B2/3 power law," the key signature of semi-Dirac fermions.

Yinming Shao et al, Semi-Dirac Fermions in a Topological Metal, Physical Review X (2024). DOI: 10.1103/PhysRevX.14.041057
Part 2

Comment by Dr. Krishna Kumari Challa on December 11, 2024 at 9:35am

Particle that only has mass when moving in one direction observed for first time

For the first time, scientists have observed a collection of particles, also known as a quasiparticle, that's massless when moving one direction but has mass in the other direction. The quasiparticle, called a semi-Dirac fermion, was first theorized 16 years ago, but was only recently spotted inside a crystal of semi-metal material called ZrSiS. The observation of the quasiparticle opens the door to future advances in a range of emerging technologies from batteries to sensors, according to the researchers.

The researchers  recently published their discovery in the journal Physical Review X.

A particle can have no mass when its energy is entirely derived from its motion, meaning it is essentially pure energy traveling at the speed of light. For example, a photon or particle of light is considered massless because it moves at light speed. According to Albert Einstein's theory of special relativity, anything traveling at the speed of light cannot have mass.

In solid materials, the collective behavior of many particles, also known as quasiparticles, can have different behavior than the individual particles, which in this case gave rise to particles having mass in only one direction.

The team's analysis showed the presence of semi-Dirac fermions at the crossing points. Specifically, they appeared massless when moving in a linear path but switched to having mass when moving in a perpendicular direction.

Semi-Dirac fermions were first theorized in 2008 and 2009 by several teams of researchers, including scientists from the Université Paris Sud in France and the University of California, Davis. The theorists predicted there could be quasiparticles with mass-shifting properties depending on their direction of movement—that they would appear massless in one direction but have mass when moving in another direction.

Sixteen years later, researchers accidentally observed the hypothetical quasiparticles through a method called magneto-optical spectroscopy. The technique involves shining infrared light on a material while it's subjected to a strong magnetic field and analyzing the light reflected from the material.

Part 1

Comment by Dr. Krishna Kumari Challa on December 10, 2024 at 12:20pm

Scientists discover more mitochondria-like symbionts with surprising metabolic capacities

In 2021, scientists at the Max Planck Institute for Marine Microbiology in Bremen, Germany, reported an astonishing new form of symbiosis: They found a unique bacterium that lives inside a ciliate—a unicellular eukaryote—and provides it with energy. The symbiont's role is thus strongly reminiscent of mitochondria, with the key difference that the endosymbiont derives energy from the respiration of nitrate, not oxygen.

Now the researchers  set out to learn more about the environmental distribution and diversity of these peculiar symbionts.

The scientists set out to look for molecular signatures of the symbiont in huge public sequencing databases, which contain vast amounts of genetic data from all kinds of environmental samples. And indeed, they detected these symbionts in about 1,000 different datasets.

The scientists were surprised how ubiquitous they are. They could find them on every inhabited continent. They learned  that they can live not only in lakes and other freshwater habitats but also in groundwater and even wastewater.

The scientists discovered not only the original symbiont in these datasets, but also some new close relatives.

The scientists  were in for another surprise—these respiratory symbionts can do new tricks. 

Unlike the original symbiont species, which can only perform anaerobic respiration (i.e., denitrification), all new symbiont species actually encode a terminal oxidase—an enzyme that enables them to also respire oxygen in addition to nitrogen. This can explain why we find these symbionts also in environments that are fully or partially toxic.

Daan R. Speth et al, Genetic potential for aerobic respiration and denitrification in globally distributed respiratory endosymbionts, Nature Communications (2024). DOI: 10.1038/s41467-024-54047-x

Comment by Dr. Krishna Kumari Challa on December 10, 2024 at 12:11pm

Blue-throated macaws have advanced motor imitation capabilities, study shows

Blue-throated macaws, a critically endangered parrot species, have demonstrated automatic imitation of intransitive (goal-less) actions—a phenomenon previously documented only in humans.

In a study conducted by an international team of researchers, scientists reveal that macaws involuntarily copy intransitive movements.

This finding, in addition to the well-known vocal mimicry skills of parrots, highlights their remarkable motor imitation abilities. The research also suggests the possibility of a mirror-neuron system in parrots, akin to that found in humans.

Imitation of goal-less intransitive actions is a cornerstone of human cultural evolution. A large part of human culture comprises the transmission of technical skills, usually involving tools. Another substantial part is the learning of cultural conventions, which encompasses high-fidelity copying of gestures or movements and fosters social bonding and prosocial behaviors.

Previous studies have shown that humans mimic gestures involuntarily—what is known as automatic imitation. Until now, evidence of such automatic imitation in non-human animals was limited to transitive (object-directed) actions, such as grasping objects, as observed in dogs and budgerigars.

In their study, now published in iScience, the researchers trained macaws to perform two distinct actions ("lift leg" and "spread wings") in response to specific hand signals. Birds were then divided into two groups: Macaws in the compatible group received a reward when they mimicked the action of another macaw (demonstrator). Birds in the incompatible group received a reward when they did not imitate the action, but performed exactly the opposite one.

The incompatible group struggled to suppress their automatic tendency to mimic the demonstrator's action. This resulted in more incorrect responses and longer reaction times compared to the compatible group.

The findings are remarkable because they show, for the first time, a non-human animal involuntary imitation of intransitive actions.

In humans, this behavior is linked to neural circuits involving mirror neurons, which activate during both the observation and execution of the same action. While this study does not directly prove the presence of mirror neurons in parrots, it strongly suggests their involvement in motor imitation.

 Esha Haldar et al, Automatic imitation of intransitive actions in macaws, iScience (2024). DOI: 10.1016/j.isci.2024.111514

Comment by Dr. Krishna Kumari Challa on December 10, 2024 at 10:11am

Using the Spectral Mapping Atmospheric Radiative Transfer (SMART) model, they proposed specific wavelengths to look for among the emission lines for of HDO and H2O. HDO has strong lines in the infrared and near-infrared part of the electromagnetic spectrum, and in 2019 scientists first detected water vapor in the atmosphere of a potentially habitable planet.

Two missions in development, NASA's Habitable Worlds Observatory (HWO) that would follow the James Webb Space Telescope, and the European-led Large Interferometer For Exoplanets (LIFE), could possibly measure D/H.

It's up to the engineers and scientists designing [HWO] and [LIFE] to see if measuring D/H on exoplanets might be an achievable goal.
Looking for D/H from LIFE appears to be feasible for exoplanets with plenty of atmospheric water vapor in a region of the spectrum around 8 microns wavelength, say the researchers.

David C. Catling et al, Potential technosignature from anomalously low deuterium/hydrogen (D/H) in planetary water depleted by nuclear fusion technology, arXiv (2024). DOI: 10.48550/arxiv.2411.18595

Part 3

Comment by Dr. Krishna Kumari Challa on December 10, 2024 at 10:09am

On Earth, where humanity is currently at 0.73 on the Kardashev scale, natural deuterium in the ocean accounts for about one atom in every 6,240 atoms of hydrogen, or 35 grams of deuterium for every ton of seawater. (That's a collective 4.85 × 1013 tons of deuterium.) The D/H ratio is nearly the same in our atmosphere. Deuterium can fuse with itself and, in a chain of nuclear reactions, ultimately produces 335 gigajoules of energy per gram of deuterium.

Using Earth as a model for an exoplanet with advanced life, researchers calculated fusion power of roughly 10 times that projected for humans next century, about 100 TW in 2100 for a population of 10.4 billion (five times more than today). That 1,000 terawatts (TW)—which could be a low amount for an advanced species (or their robotic descendants!)—would deplete an Earth-like ocean's D/H value to a value found in the local interstellar medium, about 16 parts per million, in about 170 million years.

If the D/H ratio in the water of an exoplanet was found to be substantially below [interstellar medium] values...it would be strange and anomalous," the researchers write in their paper.
If, by chance, their exoplanet had an ocean only a few percent of Earth's—a so-called "land planet"—D/H would reach anomalously low values in roughly 1 to 10 million years. That's on the order of the average lifetime of a mammalian species since the Chicxulub impact ended the dinosaurs, about 3 million years.
Other planets have higher D/H values, like Venus and Mars, but processes like Venus's runaway greenhouse effect and physical escape processes on Mars have left both uninhabitable. Thus a higher D/H than Earth's "probably indicates a planet that is problematic for habitability on geologic timescales."

Calculations like these led the group to propose looking for unusually low D/H in planetary water vapor as a potential technosignature, which they call "potentially remotely detectable."
Part 2

Comment by Dr. Krishna Kumari Challa on December 10, 2024 at 9:59am

A technosignature that could detect an extraterrestrial civilization's reliance on nuclear fusion

Extraterrestrial civilizations need a great deal of energy as they advance up the Kardashev scale. Fossil fuels are finite, wind and solar energy are carbon free but not as efficient as fossil fuels, and traditional nuclear fission power depends on a supply of fissionable material and has a waste problem. Thus, any advanced alien species may well turn to nuclear fusion for their ever-increasing energy needs (unless they've discovered even better energy processes we don't yet know about).

Deuterium (D) fusion is one of the simplest forms of nuclear fusion, where D fuses with tritium or another D. As life needs water as far as we know, oceans on an advanced world could supply plenty of it in ocean water.
On Earth, water contains a natural miniscule amount of heavy water, with deuterium replacing one or both hydrogen atoms to exist as HOD or DOH and rarely as D2O. Extracting deuterium from an ocean would decrease its ratio of deuterium-to-hydrogen, D/H, including in atmospheric water vapor, while the helium produced in the nuclear reactions would escape to space. Could low values of D/H in an exoplanet's atmosphere be a technosignature of long-lived, uber-advanced extraterrestrial life?

Measuring the D/H ratio in water vapor on exoplanets is certainly not a piece of cake, though. It is not impossible either. 

One big advantage of looking for low D/H values in an exoplanet's atmosphere is that it would persist even if advanced life died out on their planet or migrated away, increasing the chances of detecting this technosignature.

Part 1

Comment by Dr. Krishna Kumari Challa on December 10, 2024 at 9:11am

I received this from RG centre for Biotechnology, Thiruvananthapuram, Kerala, (Biotechnology and disease Biology, Ministry of Science and Technology, Dept. of Biotechnology, Government of India) requesting me to share it with the general public :

Dr. Jackson James who headed the team from BRIC-Rajiv Gandhi Centre for Biotechnology (RGCB) which came up with the finding that gene mutation can cause autism.

Gene mutation likely cause for developing autism in early childhood: RGCB study

Thiruvananthapuram, Dec. 09: Autism, a developmental disorder that causes functional abnormalities in brain development, is caused by a combination of environmental and genetic factors with its symptoms manifesting in childhood as early as the age of two years. Complexities of ASD (Autism Spectrum Disorder) include single gene mutations in early development genes.

A recent RGCB study linked a novel mutation in Tlx3 gene with abnormal development of the cerebellum (a major region of the hind brain that controls balance, motor movement, and other complex functions) and autism.

The study, conducted by Dr. Jackson James and his team from BRIC-Rajiv Gandhi Centre for Biotechnology (RGCB) here, has been published in the prestigious journal iScience.

Deleting Tlx3 gene from the cerebellum of a transgenic mouse (a mouse with its DNA altered through genetic engineering techniques) embryo potentially affects coordination of cerebellum function. When these mice embryos were allowed to grow until adulthood, they developed hallmarks of autistic behavior, including abnormalities in social skills, repetitive behaviour, and motor/movement function.

The RGCB team, in collaboration with CSIR-IGIB (Council Of Scientific And Industrial Research–Institute Of Genomics And Integrative Biology (CSIR–IGIB), New Delhi, also assessed the potential for this mutation to occur in the human population and identified TLX3 mutation variants that are linked to nine ASD cases and other co-morbid neurodevelopmental conditions.

Dr. James, however, stated that a genome-wide global cohort analysis is necessary to assess the frequency of this TLX3 mutation and the extent to which the variation is linked to specific populations, such as Indians and others. Together, these results indicate how erroneous regulation of this early embryonic gene manifests into ASDs during early childhood.

RGCB Director Prof. Chandrabhas Narayana said, “Autism is a serious childhood problem across the world. In India also, it has emerged as a significant challenge for researchers and medical fraternity as autism has wide social and medical ramifications. The RGCB study will offer new insights into this behavioural disorder.”

ASDs lead to behavioural deficits, including lack of social cognition and restricted/repetitive behaviours, desires, communication, or actions in individuals.

Comment by Dr. Krishna Kumari Challa on December 9, 2024 at 10:27am

Scientists produce world's first carbon-14 diamond battery with potential lifespan of thousands of years

Scientists and engineers have successfully created the world's first carbon-14 diamond battery.

This new type of battery has the potential to power devices for thousands of years, making it an incredibly long-lasting energy source. The battery leverages the radioactive isotope, carbon-14, known for its use in radiocarbon dating, to produce a diamond battery.

Several game-changing applications are possible. Bio-compatible diamond batteries can be used in medical devices such as ocular implants, hearing aids, and pacemakers, minimizing the need for replacements and distress to patients.

Diamond batteries could also be used in extreme environments—both in space and on earth—where it is not practical to replace conventional batteries. The batteries could power active radio frequency (RF) tags where there is a need to identify and track devices either on Earth or in space, such as spacecraft or payloads, for decades at a time, thus reducing costs and extending operational lifespan.

The carbon-14 diamond battery works by using the radioactive decay of carbon-14, which has a half-life of 5,700 years, to generate low levels of power. It functions similarly to solar panels, which convert light into electricity, but instead of using light particles (photons), they capture fast-moving electrons from within the diamond structure.

Diamond batteries offer a safe, sustainable way to provide continuous microwatt levels of power. 

https://www.bristol.ac.uk/news/2024/december/diamond-battery-media-...

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