Comment

Comment by Dr. Krishna Kumari Challa on November 16, 2024 at 3:17pm

Environmental health of waste explained in 101 seconds 

Comment by Dr. Krishna Kumari Challa on November 16, 2024 at 3:13pm

The decline in global freshwater reported in the study began with a massive drought in northern and central Brazil, and was followed shortly by a series of major droughts in Australasia, South America, North America, Europe, and Africa. Warmer ocean temperatures in the tropical Pacific from late 2014 into 2016, culminating in one of the most significant El Niño events since 1950, led to shifts in atmospheric jet streams that altered weather and rainfall patterns around the world.

However, even after El Niño subsided, global freshwater failed to rebound. In fact, Rodell and team report that 13 of the world's 30 most intense droughts observed by GRACE occurred since January 2015. Researchers suspect that global warming might be contributing to the enduring freshwater depletion.
Global warming leads the atmosphere to hold more water vapor, which results in more extreme precipitation. While total annual rain and snowfall levels may not change dramatically, long periods between intense precipitation events allow the soil to dry and become more compact. That decreases the amount of water the ground can absorb when it does rain.
"Warming temperatures increase both the evaporation of water from the surface to the atmosphere, and the water-holding capacity of the atmosphere, increasing the frequency and intensity of drought conditions.

Matthew Rodell et al, An Abrupt Decline in Global Terrestrial Water Storage and Its Relationship with Sea Level Change, Surveys in Geophysics (2024). DOI: 10.1007/s10712-024-09860-w

Part 2

Comment by Dr. Krishna Kumari Challa on November 16, 2024 at 3:11pm

NASA satellites reveal abrupt drop in global freshwater levels

An international team of scientists using observations from NASA-German satellites found evidence that Earth's total amount of freshwater dropped abruptly starting in May 2014 and has remained low ever since. Reporting in Surveys in Geophysics, the researchers suggested the shift could indicate Earth's continents have entered a persistently drier phase.

From 2015 through 2023, satellite measurements showed that the average amount of freshwater stored on land—that includes liquid surface water like lakes and rivers, plus water in aquifers underground—was 290 cubic miles (1,200 cubic km) lower than the average levels from 2002 through 2014.

That's two and a half times the volume of Lake Erie lost.

During times of drought, along with the modern expansion of irrigated agriculture, farms and cities must rely more heavily on groundwater, which can lead to a cycle of declining underground water supplies: freshwater supplies become depleted, rain and snow fail to replenish them, and more groundwater is pumped.

The reduction in available water puts a strain on farmers and communities, potentially leading to famine, conflicts, poverty, and an increased risk of disease when people turn to contaminated water sources, according to a UN report on water stress published in 2024.

The team of researchers identified this abrupt, global decrease in freshwater using observations from the Gravity Recovery and Climate Experiment (GRACE) satellites, operated by the German Aerospace Center, German Research Centre for Geosciences, and NASA. GRACE satellites measure fluctuations in Earth's gravity on monthly scales that reveal changes in the mass of water on and under the ground. The original GRACE satellites flew from March 2002 to October 2017. The successor GRACE–Follow On (GRACE–FO) satellites launched in May 2018.

Part 1

Comment by Dr. Krishna Kumari Challa on November 16, 2024 at 3:06pm

How stress changes our memories: Engrams and the endocannabinoid system may inform new PTSD treatments

Researchers have uncovered that stress changes how our brain encodes and retrieves aversive memories, and discovered a promising new way to restore appropriate memory specificity in people with post-traumatic stress disorder (PTSD).

If you stumble during a presentation, you might feel stressed the next time you have to present because your brain associates your next presentation with that one poor and aversive experience. This type of stress is tied to one memory.

But stress from traumatic events like violence or generalized anxiety disorder can spread far beyond the original event, known as stress-induced aversive memory generalization, where fireworks or car backfires can trigger seemingly unrelated fearful memories and derail your entire day. In the case of PTSD, it can cause much greater negative consequences.

In a study published in Cell, researchers identify the biological processes behind stress-induced aversive memory generalization and highlight an intervention which could help restore appropriate memory specificity for people with PTSD.

People with PTSD show fearful responses to safe situations or environments. Researchers  have found a way to limit this fearful response to specific situations and potentially reduce the harmful effects of PTSD. the research team was able to block endocannabinoid  receptors on interneurons, and limit stress-induced aversive memory generalization to the specific, appropriate memory.

Stress disrupts engram ensembles in lateral amygdala to generalize threat memory in mice, Cell (2024). DOI: 10.1016/j.cell.2024.10.034. www.cell.com/cell/fulltext/S0092-8674(24)01216-9

Comment by Dr. Krishna Kumari Challa on November 16, 2024 at 2:58pm

Genes of ancient animal relatives used to grow a mouse

An international team of researchers has achieved an unprecedented milestone: the creation of mouse stem cells capable of generating a fully developed mouse using genetic tools from a unicellular organism, with which we share a common ancestor that predates animals.

This breakthrough reshapes our understanding of the genetic origins of stem cells, offering a new perspective on the evolutionary ties between animals and their ancient single-celled relatives. The research is published in the journal Nature Communications.

In an experiment that sounds like science fiction,  researchers used a gene found in choanoflagellates, a single-celled organism related to animals, to create stem cells which they then used to give rise to a living, breathing mouse.

Choanoflagellates are the closest living relatives of animals, and their genomes contain versions of the genes Sox and POU, known for driving pluripotency—the cellular potential to develop into any cell type—within mammalian stem cells. This unexpected discovery challenges a longstanding belief that these genes evolved exclusively within animals.

By successfully creating a mouse using molecular tools derived from our single-celled relatives, we're witnessing an extraordinary continuity of function across nearly a billion years of evolution. The study implies that key genes involved in stem cell formation might have originated far earlier than the stem cells themselves, perhaps helping pave the way for the multicellular life we see today.

Ya Gao et al, The emergence of Sox and POU transcription factors predates the origins of animal stem cells, Nature Communications (2024). DOI: 10.1038/s41467-024-54152-x

Comment by Dr. Krishna Kumari Challa on November 16, 2024 at 2:47pm

Astronomers discover two galaxies aligned in a way where their gravity acts as a compound lens

An international team of astronomers has discovered an instance of two galaxies aligned in a way where their gravity acts as a compound lens. The group has written a paper describing the findings and posted it on the arXiv preprint server.

Prior research has led to many findings of galaxies, or clusters of them, bending light in ways that were predicted by Einstein's theory of general relativity. Astronomers have noted that some of them work as imperfect lenses, distorting the light behind them in interesting ways.

Some researchers have also noted that elliptical galaxies can serve as a lens, serving to brighten the light behind them. In this new effort, the research team has found, for the first time, two galaxies that align in a way that allows their gravity to work as a compound lens.

A compound lens, as its name suggests, is made up of two lenses. Those made artificially are cemented together and work to correct each other's dispersion. In the astronomical case, a compound lens can be made by the dual effects of two galaxies lined up next to one another just right.

The researchers note that when the system, J1721+8842, was first discovered, it was believed that there was just one elliptical galaxy bending the light from a quasar behind it. In analyzing data over a two-year period, the researchers of this new effort found variations in the quasar imagery. They also found small bits of light that, at first glance, appeared to be duplicates from a single source.

A closer look revealed that they matched the light from the main quartet of lights—a finding that showed that all six bits of light were from the same source. Prior research had suggested such an image could be the result of a natural compound lens.

When adding data from the James Webb Space Telescope, the team found that a reddish ring that was mixed with the other lights and was thought to be an Einstein ring was, in reality, a second lensing galaxy. The researchers next built a computer model and used it to confirm that the observation they had made was indeed that of a compound lens.

F. Dux et al, J1721+8842: The first Einstein zig-zag lens, arXiv (2024). DOI: 10.48550/arxiv.2411.04177

Comment by Dr. Krishna Kumari Challa on November 16, 2024 at 2:41pm

Physicists create the first fully mechanical qubit

A team of physicists  has built the first-ever working mechanical qubit. In their paper published in the journal Science, the group describes their novel idea for creating such a qubit and how well it has worked during testing.

Researchers think quantum computers will be able to solve many types of problems that are beyond the ability of classical computers. And while much progress has been made, the goal has still not been fully realized. One of the major sticking points is the problem of virtual qubits, such as those made using electromagnetics, which produce errors that must be corrected. The research team found another way around the problem—using mechanical qubits instead.

Instead of representing data with only ones and zeroes, qubits are able to store data in a superposition of both states. For this new study, the researchers built what they describe as a membrane similar to a drum skin that can hold information as a steady state, a vibrating state or a state that is both at once.

Noting that the real problem with virtual qubits is their short duration (they pop into existence and are gone in a flash), the researchers turned to something that would last much longer—a piezoelectric disk fixed to a sapphire base. They used it as a mechanical resonator. They then attached a qubit made of a superconducting material fixed to its own sapphire base, using a special fabrication technique they developed.

The result was a qubit with coherence times that were based on the type of superconductor used and were on average better than hybrid or virtual qubits used in other systems.

Yu Yang et al, A mechanical qubit, Science (2024). DOI: 10.1126/science.adr2464

Comment by Dr. Krishna Kumari Challa on November 14, 2024 at 11:15am

Comment by Dr. Krishna Kumari Challa on November 14, 2024 at 10:34am

Human induced evolution

A native New Zealand insect that once mimicked its toxic neighbor has changed color in deforested areas, in a striking example of human-induced evolution.

The long-tailed stonefly, Zelandoperla, had a clever strategy to avoid predation from birds: it mimicked the appearance of a uniquely toxic stonefly, Austroperla, a forest dweller that deters predators by producing cyanide.

Researchers  have found that in deforested areas without Austroperla in the picture, and with fewer bird predators, some Zelandoperla have given up their guise.
The findings highlight "the possibility for populations to adapt rapidly in the wake of sudden environmental change," the team writes in their published paper.

While the long-tailed stonefly has no toxins of its own, it has managed to pull off a convincing impersonation of Austroperla using its genetic toolkit, which colored some of the insects a dark shade of ebony.

The disguise worked to deter their feathered predators, which, unable to tell the difference, steered clear of both the toxic stonefly and its mimic.

But Austroperla is a forest creature: it lives in streams where it feeds on leaves and woody debris. In deforested areas, its preferred food sources are lacking, and Austroperla has become less common.

The removal of forests since humans arrived has removed the poisonous species. 
As a result, in deforested regions the mimicking species has abandoned this strategy – as there is nothing to mimic – instead evolving into a different colour.

The scientists used a combination of field observations, predation experiments, and gene map analysis to show the insect's response to human-driven change.

https://www.science.org/doi/10.1126/science.ado5331

Comment by Dr. Krishna Kumari Challa on November 14, 2024 at 10:05am

The numbers from the United States are far more disturbing, with a 2020 report showing that between 2013 and 2017, younger-onset dementia in 30- to 44-year-olds had spiked by 373%.

All age groups recorded an increase, with a 311% rise in the 45–54 age group, and a 143% rise for 55–64s, but it was the Millennials and Gen Xers who were the hardest hit.

Some people cite the improvement in diagnostic techniques as being behind this change, but if that were the case, we would be seeing a similar increase across all ages. We aren't.
The report did not speculate on the cause for this dramatic increase in younger-onset dementia. Still, there is nothing else that has happened in the past 10 years that can explain this change apart from the global rise to dominance of the smartphone from about 2012.

We know that people with lower cognitive capacity are more susceptible to dementia.

We know overusing smartphones can result in lower cognitive capacity.

We may argue that correlation is not causation, but the correlation between lead in water and problems with children's brain development seen across the world from the mid-20th century was enough for governments to spend the equivalent of millions of dollars to replace all our water pipes.

Younger-onset dementia rates have risen at the same time as smartphones have taken over every part of our lives, and dismissing this as a coincidence will not address the problem.

Screen use may or may not be the original cause of the problem, but the fact that excessive and ongoing screen use leads to changes in the brain means there is a relationship that warrants urgent further investigation.

https://lighthouse.mq.edu.au/article/november-2024/opinion-we-need-...

Part 2

**

• ‹ Previous
• 1
• …
• 140
• 141
• 142
• 143
• 144
• …
• 1111
• Next ›
• Page