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Comment by Dr. Krishna Kumari Challa on March 13, 2024 at 10:00am

How invisible presences hijack the social counting brain in Parkinson's disease

If you had to estimate the number of people in a room, without counting them one by one, by nature you would overcount them. That's because—simply put from a Darwinian perspective of how we have evolved—it's better to overcount potentially harmful agents and predators than to underestimate them. This overcounting social behavior is shown to be true in humans as well as animals. It's certainly better to detect too many tigers (even if absent) during a jungle excursion than to miss a hungry one.

Now,  neuroscientists show that if you experience hallucinations, especially when related to an illness like Parkinson's disease, then you will overestimate the number of people in a room to a greater degree. They also show that if you have hallucinations but are asked to estimate the number of boxes in a room, which are inanimate control objects, then no extra overestimation occurs, shedding light on the social nature of this overcounting.

The results are published in Nature Communications.

The fact that patients of Parkinson's disease have a much higher over-estimation in counting people is mind-blowing because Parkinson's disease is classically viewed as a movement disorder.

This new work shows that Parkinson's may also be a perceptual disorder, especially of social stimuli, and that invisible presences in Parkinson's disease may impair even more the counting social brain.

The category of hallucinations investigated by the neuroscientists is called presence hallucinations, for which people report an invisible presence next to them, even though no one is there. Such hallucinations are considered to be minor compared to visual hallucinations, for instance. They may be experienced early on in patients with Parkinson's disease, sometimes even before diagnosis. Presence hallucinations are also a known early marker of cognitive decline in Parkinson's disease.

The results of the study support the idea that the invisible presence (and related brain mechanisms) are responsible for this overcounting of people. When presence hallucinations are experienced—either due to disease or induced artificially—this extra presence gets subconsciously translated into an over-estimation of the number of people we think we see. In essence, the invisible presence gets added in the counting process, but only in counting people.

Nature Communications (2024).

https://www.nature.com/articles/s41467-024-45912-w

Comment by Dr. Krishna Kumari Challa on March 13, 2024 at 9:47am

Age-related changes in skin may contribute to melanoma metastases

Age-related changes that cause the skin to stiffen and become less elastic may also contribute to higher rates of metastatic skin cancer in older people, according to research by investigators.

 The study, published March 12 in Nature Aging, shows that increased stiffness in aging skin increases the release of a protein called ICAM1. Increased ICAM1 levels stimulate blood vessel growth in the tumor, helping it grow. It also makes the blood vessels "leaky," enabling tumor cells to escape and spread throughout the body more easily.

The discoveries might also lead to new approaches to treating other age-related cancers. Previous therapies targeting growth factors that contribute to angiogenesis have failed in many tumor types, including melanoma. But ICAM1 provides a promising new target.

Nature Aging (2024).

• Age-Related Lung Changes Provide Pathway for Metastatic Growth of D...
• Age is a primary determinant of melanoma treatment resistance, two ...

Comment by Dr. Krishna Kumari Challa on March 13, 2024 at 9:40am

Spring irrigation can reduce summer heat wave events

Heat waves are becoming more extreme as climate change exacerbates, with susceptible locations experiencing more frequent, prolonged and higher intensity events. As such, they pose a hazard to agricultural practices that rely upon sufficient water to ensure sustainable food supplies.

Irrigation is used to help alleviate warm, dry climates by maintaining soil moisture levels to promote growth as well as exerting a cooling effect on the immediate local climate (within a few meters of the surface), but extracts freshwater from resources that may also be threatened by shrinkage with more evaporation in a warmer world.

New research, published in Geophysical Research Letters, has investigated the dampening effect irrigating land in spring can have on the intensity of summer heat waves by retaining higher soil moisture levels between seasons, known as soil moisture memory.

The researchers  analyzed models of root-zone soil moisture data from 1980 to 2018 and combined this with a forecasting model to simulate the effect of irrigation on extreme summer heat wave events from 2004 to 2018. They ran three tests, one with no irrigation, one with both spring and summer irrigation, and the last solely with spring irrigation.

The researchers found that spring irrigation reduced the intensity of summer heat waves by 0.29°C and 2.5 days, and when combined with summer irrigation this extends to a reduction of 1°C and 6.5 days. With the simulated regional means of extreme heat waves being temperatures of 35.8°C and lasting 21.7 days, the combined impact of spring and summer irrigation can have a significant effect, especially on the longevity of the event.

This research is important as it suggests applying a surplus of water in spring helps to alleviate water stress in the following summer months, and is less wasteful of water resources that evaporate more in summer (especially from the top 1 m of soil), while also supporting regions that experience an imbalance in precipitation through the year.

Though the intensity of extreme heat wave events may be reduced, these climatic challenges will persist in the future, so it is important to apply these results in water resource management and adaptation planning strategies.

Guoshuai Liu et al, Spring Irrigation Reduces the Frequency and Intensity of Summer Extreme Heat Events in the North China Plain, Geophysical Research Letters (2024). DOI: 10.1029/2023GL107094

Comment by Dr. Krishna Kumari Challa on March 13, 2024 at 9:15am

False GPS signal surge makes life hard for pilots

False GPS signals that deceive on-board plane systems and complicate the work of airline pilots are surging near conflict zones.

A ground collision alert sounds in the cockpit, for instance, even though the plane is flying at high altitude—a phenomenon affecting several regions and apparently of military origin.

This includes the vicinity of Ukraine following the Russian invasion two years ago, the eastern Mediterranean and the air corridor running above Iraq, according to pilots and officials.

Disruptions which were previously limited to jamming preventing access to signals from geolocation satellites are now also taking a more dangerous form making it difficult to counter spoofing.

This sees a plane receive false coordinates, times and altitudes.

By comparing this data to the geographical maps in its memory banks, its systems can conclude there is imminent danger ahead. There were some untimely alarms ordering people to pull back as far as possible on the stick and apply full power to avoid an obstacle, while the plane was in cruise... and in any case no mountain reaches so high.

The problem  is that this adulterated information enters the navigation system and can cause false alerts hours afterwards as the flight nears its destination.

At first, crews quickly see that it is a false alarm. But as it is an alarm warning of immediate danger, control towers ask the crews to still carry out the emergency maneuver, to make a return and an analysis. If the problem occurs a second time and the analysis has not revealed any danger, then the only way is to turn off this alarm, knowing other systems remain active to detect possible risk.

Since the start of the war in Ukraine, the European Union Aviation Safety Agency (EASA) has been warning that GNSS signal disruptions have intensified, affecting relatively remote regions beyond the conflict zone such as Finland and the Mediterranean.

In certain cases, this can lead to a modified trajectory or even a changed destination as it was impossible to carry out a landing in secure conditions, the EASA says.

Source: AFP and other news agencies

Comment by Dr. Krishna Kumari Challa on March 13, 2024 at 7:18am

For people who speak many languages, there's something special about their native tongue

A new study of people who speak many languages has found that there is something special about how the brain processes their native language.

In the brains of these polyglots—people who speak five or more languages ( I am one of them too!)—the same language regions light up when they listen to any of the languages that they speak. In general, this network responds more strongly to languages in which the speaker is more proficient, with one notable exception: the speaker's native language. When listening to one's native language, language network activity drops off significantly.

The findings suggest there is something unique about the first language one acquires, which allows the brain to process it with minimal effort, the researchers say.

Something makes it a little bit easier to process—maybe it's that you've spent more time using that language—and you get a dip in activity for the native language compared to other languages that you speak proficiently.

The brain's language processing network, located primarily in the left hemisphere, includes regions in the frontal and temporal lobes. In a 2021 study, researchers found that in the brains of polyglots, the language network was less active when listening to their native language than the language networks of people who speak only one language.

In the new study, the researchers wanted to expand on that finding and explore what happens in the brains of polyglots as they listen to languages in which they have varying levels of proficiency. Studying polyglots can help researchers learn more about the functions of the language network, and how languages learned later in life might be represented differently than a native language or languages.

With polyglots, you can do all of the comparisons within one person. You have languages that vary along a continuum, and you can try to see how the brain modulates responses as a function of proficiency.

Saima Malik-Moraleda et al, Functional characterization of the language network of polyglots and hyperpolyglots with precision fMRI, Cerebral Cortex (2024). DOI: 10.1093/cercor/bhae049

Comment by Dr. Krishna Kumari Challa on March 10, 2024 at 12:49pm

A look inside the Harvard Herbaria

Comment by Dr. Krishna Kumari Challa on March 9, 2024 at 12:00pm

Listen to a star ‘twinkle’

Comment by Dr. Krishna Kumari Challa on March 9, 2024 at 11:08am

Australia's Great Barrier Reef in grip of 'mass bleaching event'

A "mass bleaching event" is unfolding on Australia's famed Great Barrier Reef, authorities said recently, as warming seas threaten the spectacular home to thousands of marine species.

Often dubbed the world's largest living structure, the Great Barrier Reef is a 2,300 kilometre (1,400 mile) expanse of tropical corals that house a stunning array of biodiversity.
But repeated mass bleaching events have threatened to rob the tourist drawcard of its wonder, turning banks of once-vibrant corals into a sickly shade of white.

"We know the biggest threat to coral reefs worldwide is climate change. The Great Barrier Reef is no exception.
The damaging mass bleaching event—the seventh since 1998—was confirmed by government scientists following aerial surveys of 300 shallow reefs.

The Australian Reef Authority said it would now need to conduct further surveys to assess the severity and extent of bleaching.

Coral bleaching occurs when underwater temperatures are more than 1 degree warmer than the long-term average.

As corals come under heat stress, they expel algae living within their tissues—draining them of their vibrant colours.
Ocean temperatures along the Great Barrier Reef have approached record levels in the past few weeks, according to official monitoring.
This bleaching event is unfolding in an area where corals have not been previously exposed to these extreme temperatures.
Undoubtedly climate change was "putting tremendous pressure" on the Great Barrier Reef.
The reef is no longer capable of recovering to the mix of coral species and the sizes of corals that were there 20 years ago, according to scientists.
The fate of the reef has been a recurrent source of tension between the Australian government and the United Nations' World Heritage Committee.

The World Heritage Committee has threatened to put the reef on a list of "in danger" global heritage sites, a move that would likely damage its allure for international tourists.
Before this event, Australia's Great Barrier Reef suffered mass coral bleaching in 1998, 2002, 2016, 2017, 2020 and 2022.
Source: AFP and other news agencies

Comment by Dr. Krishna Kumari Challa on March 9, 2024 at 10:46am

For the study, the 5-carbon sugar deoxyribose, which forms the backbone of DNA, was replaced by a 4-carbon sugar. In addition, the number of nucleobases was increased from four to six. By exchanging the sugar, the TNA is not recognized by the cell's own degradation enzymes. This has been a problem with nucleic acid-based therapeutics, as synthetically produced RNA that is introduced into a cell is rapidly degraded and loses its effect.

The introduction of TNAs into cells that remain undetected could now maintain the effect for longer. "In addition, the built-in unnatural base pair enables alternative binding options to target molecules in the cell.

TNAs could also be used for the targeted transport of drugs to specific organs in the body (targeted drug delivery) as well as in diagnostics; they could also be useful for the recognition of viral proteins or biomarkers.

Hannah Depmeier et al, Expanding the Horizon of the Xeno Nucleic Acid Space: Threose Nucleic Acids with Increased Information Storage, Journal of the American Chemical Society (2024). DOI: 10.1021/jacs.3c14626

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Comment by Dr. Krishna Kumari Challa on March 9, 2024 at 10:45am

Researchers develop artificial building blocks of life

For the first time, scientists  have developed artificial nucleotides, the building blocks of DNA, with several additional properties in the laboratory, which could be used as artificial nucleic acids for therapeutic applications.

DNA carries the genetic information of all living organisms and consists of only four different building blocks, the nucleotides. Nucleotides are composed of three distinctive parts: a sugar molecule, a phosphate group, and one of the four nucleobases adenine, thymine, guanine, and cytosine.

The nucleotides are lined up millions of times and form the DNA double helix, similar to a spiral staircase. Scientists have now shown that the structure of  nucleotides can be modified to a great extent in the laboratory. The researchers developed so-called threofuranosyl nucleic acid (TNA) with a new, additional base pair.

But artificial nucleic acids differ in structure from their originals. These changes affect their stability and function.  However,  threofuranosyl nucleic acid is more stable than the naturally occurring nucleic acids DNA and RNA, which brings many advantages for future therapeutic use.

These are the first steps on the way to fully artificial nucleic acids with enhanced chemical functionalities. The study "Expanding the Horizon of the Xeno Nucleic Acid Space: Threose Nucleic Acids with Increased Information Storage' was published in the Journal of the American Chemical Society.

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